REPORT ON HYDROGEN PRODUCTION IN INDIA
Transcript of REPORT ON HYDROGEN PRODUCTION IN INDIA
APPENDIX -IV
REPORT ON
HYDROGEN PRODUCTION IN INDIA
Prepared by the
Sub-Committee on Research, Development & Demonstration
for Hydrogen Energy and Fuel Cells of the
Steering Committee on Hydrogen Energy and Fuel Cells
Ministry of New and Renewable Energy,
Government of India, New Delhi
June, 2016
FOREWORD
Till the end of 20th Century carbonaceous substances like coal, natural
gas, petroleum derived oils and wood were fulfilling the of energy needs of
human society for heat, light and power (both motive and electric). With the
passage of time, the rising world population and urge for better living
standards by the people of developing regions of the world have resulted in
over exploitation of conventional energy resources. This in turn has led to the
increase in the demand for energy and reduction in availability of conventional
fuels. Emission of various types of pollutants (such as particulates, carbon
dioxide, and un-burnt hydrocarbons) as a result of the use of these fuels is not
only affecting the health of living beings adversely but also contributing to
greenhouse effect and climate changes. In view these concerns and ensuring
energy security, the focus in the futuristic energy planning is shifting from
carbon rich to carbon neutral and carbon free new and renewable energy
sources. Hydrogen has been considered and identified as the potential energy
carrier and as a leading contender for the “ideal” energy option of the future.
On combustion it emits only water vapor. It may be produced through natural
gas reforming, coal and biomass gasification, thermo-chemical route using the
heat available at high temperature from nuclear reactors, electrolysis of water
with surplus electricity available from grid or that produced from renewable
sources of energy like hydro, wind, solar etc. Biological (fermentative and bio-
photolysis), photo-catalytic splitting of water (or photolysis), and photo-
electrochemical methods are being considered as futuristic routes of
producing hydrogen. Sufficient amount of hydrogen is also produced as by-
product in Chlor-Alkali units and petroleum refineries
In view of the rising aspiration of the increasing population, India is also
concerned about the climate change and is therefore striving for developing
technologies for harnessing renewable energy sources. Hence, hydrogen
energy and fuel cell technologies are of utmost importance, which India needs
to develop in a mission mode. Though the Ministry of New and Renewable
Energy (MNRE) and several other government agencies at the central and
state government levels are providing support for research, development and
demonstration of hydrogen production and application, yet India is lagging
behind while considering the global scenario. The MNRE, Government of
India constituted a high power Steering Committee to prepare a status report
and suggest the way forward for development of hydrogen energy and fuel
cell technologies in the country. One of the five sub-committees was entrusted
under the chairmanship of the undersigned with the responsibility of preparing
this particular document focusing on the research and development of various
hydrogen production technologies of relevance to the country.
This document is the result of the combined effort of all the members of
the sub-committee, experts working in the area of hydrogen production,
officials and staff of MNRE.
I am indebted to all the Members of the Sub-Committee and Special
Invitees for their contribution, Dr. M. R. Nouni, Scientist ‘G’, Ministry of New
and Renewable Energy and also the officials of the Project Management Unit
– Hydrogen Energy and Fuel Cells at the Ministry, Dr. Jugal Kishor and Dr. S.
K. Sharma in particular for their active role in organizing meetings and
preparing this document.
30th June, 2016
(Prof. S. N. Upadhyay),
Chairman,
Sub-Committee on Research, Development &
Demonstration for Hydrogen Energy and Fuel Cells
CONTENTS
Sl. No.
Subject Page No.
I
Composition of the Sub-Committee on Research,
Development & Demonstration for Hydrogen Energy and
Fuel Cells
i
II Terms of Reference ii
III Details of Meetings iii
1 Executive Summary 1
2 Introduction 25
3 Hydrogen Production using Thermo-chemical Route from
Carbonaceous feed-stocks:
(i) Carbonaceous feed-stock
(ii) Biomass feed-stock
35
37
54
4 Hydrogen Production by Electrolysis of Water 69
5 Bio-Hydrogen and Bio-Methane Production 95
6 Hydrogen Production through Thermochemical Routes
(Iodine-Sulphur and Copper-Chlorine Cycles)
105
7 Hydrogen Production by Photo-electrochemical Water
Splitting
149
8 Hydrogen Production by Other Technologies 163
9 Action Plan 171
10 Financial Projections and Time Schedule of Project
Activities
181
11 Conclusions and Recommendations 189
12 Bibliography 199
13 Annexure 207
i
I Composition of Sub-Committee on Research,
Development & Demonstration for Hydrogen Energy and
Fuel Cells
1. Prof. S. N. Upadhyay, Former Director, Institute of Technology, Banaras
Hindu University, Varanasi and DAE-Raja Ramanna Fellow in the
Department of Chemical Engineering and Technology, Indian Institute of
Technology (Banaras Hindu University), Varanasi - Chairman
2. Ms. Varsha Joshi, Joint Secretary / Shri A. K. Dhussa, Adviser
(December, 2013 to March, 2015) / Dr. Bibek Bandyopadhyay, Adviser
(upto December, 2013), MNRE
3. Dr. Sanjay Bajpai, Scientist ‘G’, Department of Science and Technology,
Ministry of Science and Technology, New Delhi
4. Dr. Ashish Lele, CSIR-National Chemical Laboratory, Pune
5. Dr. S. Aravamuthan, Sci./ Engr.- ‘H’ & Deputy Director, Vikram Sarabhai
Space Centre, Indian Space Research Organisation, Thiruvanthapuram
6. Shri A. Srinivas Rao, SO/G, Chemical Technology Division, Bhabha
Atomic Research Centre, Mumbai
7. Dr. K. S. Dhathathreyan, Head, Centre for Fuel Cell Technology, Chennai
(Retired on 31.01.2016)
8. Prof. O.N. Srivastava, Emeritus Professor, Banaras Hindu University,
Varanasi
9. Prof. B. Viswanathan, Emeritus Professor, Indian Institute of Technology
Madras, Chennai
10. Prof. Debabrata Das, Indian Institute of Technology Kharagpur,
Kharagpur
11. Prof. L. M. Das, currently Emeritus Professor, Indian Institute of
Technology Delhi, New Delhi (Retired on 30.06.2014)
12. Executive Director, Centre for High Technology, Noida
13. Dr. P. K. Tiwari, Desalination Division, Bhabha Atomic Research Centre
as Representative of Principal Scientific Adviser to Govt. of India,
currently Raja Ramanna Fellow at the Prof. Homi Bhabha National
Institute, BARC, Mumbai (Retired on 31.01.2015)
14. Shri Sanjay Bandyopadhyay, National Automotive Testing and R&D
Infrastructure Project (NATRIP), New Delhi / Shri Neeraj Kumar, Deputy
Secretary, Ministry of Heavy Industries & Public Enterprises, (Repatriated
to Parent Department in January, 2015) / Shri Nitin R. Gokarn, NATRIP,
New Delhi (Repatriated in June, 2014 to Parent Cadre)
Special Invitees:
15. Prof. S. Dasappa, Indian Institute of Science, Bangalore
16. Dr (Mrs.) V. Durga Kumari, Indian Institute of Chemical Technology,
Hyderabad
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II Terms of Reference
1. To review national and international status of Research & Development,
Technology Development and Demonstration with a view to identify the
gaps.
2. To suggest the strategy to bridge the identified gaps and the time frame for
the same.
3. To assess R & D infrastructure in the country.
4. To identify projects and prioritize them for support with the result oriented
targets.
5. To identify institutes to be supported for augmenting R&D facilities
including setting-up of Centre(s) of Excellence and suggest specific
support to be provided.
6. To suggest strategy for undertaking collaborative R & D among leading
Indian academic institutions and research organisations and also with
international organisations.
7. To examine setting-up of a National Hydrogen Energy and Fuel Cell
Centre as an apex facility.
8. To suggest strategy to take-up projects in Public-Private Partnership mode
for the development of technologies based on transparency, accountability
and commitment for deliverables.
9. To identify the technologies, which can be adopted for applications with
time line?
10. To re-visit National Hydrogen Energy Road Map with reference to
Research, Development & Demonstration and Technology Development
activities
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III Details of Meetings
The Sub-Committee on Research, Development and Demonstration
(RD&D) met on 09.12.2013 and had detailed presentations and discussions
on the activities relating to RD&D in the areas of hydrogen production, its
storage & applications in power generation and vehicles based on IC engine
& fuel cell technologies. The second meeting of the Sub-Committee was held
on 03.03.2014 for the identification of thrust areas for hydrogen production, its
storage & applications in power generation and vehicles based on IC engine,
so as the Ministry may consider supporting projects in these areas. In the
third meeting held on 18.11.2014 in the Ministry of New and Renewable
Energy, New Delhi, detailed presentations and discussions were made on
hydrogen production. Based on the input received from the expert members
of the Sub-Committee and experts outside the Sub-Committee, a draft report
on Hydrogen Production was prepared. This Draft Report was presented in
the 5th meeting of the Steering Committee on Hydrogen Energy and Fuel
Cells held on 11.08.2015 in MNRE, which gave some suggestions to modify
the report. The draft report was modified incorporating these suggestions. The
Steering Committee further requested that the Chairpersons of all the five
Sub-Committees to meet and discuss uniformity of the reports and alignment
of outcome of the reports. Accordingly, the draft report was again modified
based on the suggestions given / decisions taken in the meetings of the
Chairpersons of the Sub-Committees held on 11.09.2015, 16.12.2015 and
18.01.2016.
Note: Since the Sub-Committees on different aspects (Fuel Cell
Development; Hydrogen Storage & Applications other than Transportation;
Transportation through Hydrogen fuelled Vehicles and IPR, PPP, Safety,
Standards, Awareness & Human Resource Development) of the Steering
Committee on Hydrogen Energy and Fuel Cells, covered activities relating to
Research, Development & Demonstration (RD&D) in their respective areas, it
was decided that the Sub-Committee on Research, Development &
Demonstration (RD&D) would focus only on hydrogen production.
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1.0 Executive Summary
Preamble
1.1 Use of fossil fuels has become a part of daily energy needs and their
requirement is increasing with the passage of time. Consumption of fossil
fuels gives rise to the greenhouse gas emissions in the environment and
causes ambient air pollution, which have now become global concerns. This
coupled with the limited reserves of fossil fuels have encouraged and
promoted the development and use of new and renewable energy sources,
including hydrogen energy as an alternative clean fuel. The technologies for
production of hydrogen from new and renewable sources of energy are not
yet mature and the cost of hydrogen produced through new and renewable
energy sources is still very high and is not competitive to that produced from
fossil fuels. In order to meet the future energy demands in sustainable and
environment friendly manner, technologies are required to be developed for
the production, storage and applications of hydrogen in transportation sector
as well as for portable and stationary distributed & non-distributed power
generation. In some countries governments have started supporting these
efforts.
1.2 Hydrogen is an energy carrier (a secondary source of energy) and is
available in chemically combined forms in water, fossil fuels, biomass etc. It
can be liberated with the electrical or heat energy input (generated from some
primary energy source like fossil fuel, nuclear power or a renewable energy
source such as - solar, wind, hydro-electricity, etc.). Presently the agriculture
sector is the largest user of hydrogen (as nitrogenous fertilizer), with 49% of
hydrogen being used for ammonia production (Konieczny et al., 2008)
1.3 Approximately 95% of the hydrogen produced presently comes from
carbonaceous raw material, primarily of fossil origin. About 4% is produced
through electrolysis of water.
1.4 Hydrogen is also produced as a by-product in Chlor-Alkali industries.
There are around 40 such units in India, which produced nearly 66000 tons of
by-product hydrogen during 2013-14. Around 90% of this by-product
hydrogen is utilized for captive and other uses. Only a fraction of this
hydrogen is currently used for energy purposes. Around 6600 tons of this
hydrogen is still unutilized.
1.5 Hydrogen Production Technologies
a) Reforming of Carbonaceous Sources: Conventional technologies for
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hydrogen production are: i) Steam Methane Reforming ii) Partial Oxidation,
iii) Auto-Thermal Reforming, iv) Methanol Reforming, v) Ammonia Cracking,
vi) Thermo-catalytic Cracking of Methane, and vii) Novel Reformer
Technologies. Steam Methane Reformers are commercially available for
hydrogen production. In the United States, most hydrogen (over 90%) is
manufactured by steam reforming of natural gas presently. High purity
industrial hydrogen with 99.999% purity is produced from commercial
hydrogen by pressure swing adsorption systems or by palladium gas
membranes. Technologies for coal gasification are commercially available
internationally. At national level, hydrogen is produced commercially in
fertilizer plants and petroleum refineries by reformation of natural gas. There
are extensive industry and government programs addressing to particular
technical issues for small-scale reformers, and for syngas production in the
country.
1.5.1 Compact “Fuel Cell Type” Low Pressure and Temperature Steam
Methane Reformers were developed in small sizes to produce 50 to 4000
Nm3 H2/day internationally (Halvorson, et al, 1997).These have recently been
adapted for stand-alone hydrogen production. Energy conversion efficiency
in the range of 70%-80% is possible for these units. Internationally, a novel
gasoline steam reformer with micro-channels was developed to reduce the
size and cost of automotive reformers. Another 1 kW plate reformer, a more
compact, low cost standardized design having better conversion efficiency,
and faster start-up was developed for fuel cell systems. It yielded increased
energy conversion efficiency (from about 70% to 77%) by reducing heat
losses. Its lifetime is also expected to be increased from 5 to 10 years.
1.5.2 Membrane Reactors for Steam Reforming is another promising
technology. Depending on the temperature, pressure and the reactor length,
methane is completely converted, and very pure hydrogen is produced. This
allows its operation at lower temperature and lower cost. A potential
advantage of this system is simplification of the process design and capital
cost reduction. Japan has built and tested a small membrane reactor for
production of pure hydrogen from natural gas (at a rate of 15 Nm3/h).
1.5.3 Partial Oxidation (POX) Reformer: Large-scale partial oxidation
systems have been used commercially to produce hydrogen from
hydrocarbons such as residual oil, for industrial applications. Small-scale
partial oxidation systems have recently become commercially available, but
are still undergoing intensive R&D. These reactors are more compact than a
steam reformer with efficiency of 70-80%. This technology is being used to
install a natural gas reformer filling station to supply hydrogen to fuel cell
buses and Hythane® buses at Thousand Palms, California. Several
companies are involved in developing multi-fuel fuel processors for 50 kW fuel
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cell vehicle power plants and to develop gasoline fuel processors based on
POX technology.
1.5.4 Auto-thermal reformers combine some of the best features of steam
reforming and partial oxidation systems. Several companies are developing
small auto-thermal reformers for converting liquid hydrocarbon fuels to
hydrogen for the use in fuel cell systems. The auto-thermal reformer requires
no external heat source and no indirect heat exchangers. Heat generated by
the partial oxidation is utilized to drive steam reforming reaction. This is more
compact than conventional steam reformers, and will have a lower capital cost
and higher system efficiency than partial oxidation systems. Auto-thermal
reformers are being developed for PEMFC systems by a number of groups
1.5.5 Methanol Reformation takes place with steam at moderate
temperatures (250-350oC). These reformers have been demonstrated by
several automakers in PEM fuel cell vehicles, where methanol is stored on-
board. But no fuel cell vehicle manufacturer is currently using this technology.
The advantages are compactness, better heat transfer, faster start-up and
potentially lower cost. Internationally, units are produced for steam reforming
of alcohols, hydrocarbons, ethers and military fuels. CJB Ltd., a British
company built and tested a plate type steam methanol reformer and
integrated the fuel cell system. A multi-fuel processor was demonstrated for
pure hydrogen production via steam reforming of methanol, using a palladium
membrane and micro-reactor technology to create a portable hydrogen
source for fuel cells.
1.5.6 Ammonia Cracking: Ammonia is widely distributed in the country and
available at low cost. It is relatively easy to transport and store, compared to
hydrogen. It can be cracked at 9000C with up to 85% efficiency. Water is not
required as co-feed. A costly separation unit Pressure Swing Adsorption unit
for separating H2 and N2 would be required. Thermo-catalytic cracking of
methane is still far from commercial application for hydrogen production. The
primary issues are low efficiency of conversion and coking but relatively low
capital costs are projected.
1.5.7 Sorbent-enhanced Catalytic Steam-reforming System: Syngas,
produced using novel reformer technologies, has a substantially higher
fraction of hydrogen than that produced in a catalytic steam-reforming reactor.
Sorbent-enhanced systems are still at the demonstration stage, and show
promise for low cost. Issues to be resolved include catalyst and sorbent
lifetime and system design.
1.5.8 Hydrogen Separation through Ceramic Membrane: Globally, some
research groups are developing ceramic membrane technology for separation
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of hydrogen from syngas. The membranes are non-porous, multi-component
metallic oxides that operate at high temperature (>700oC) and have high
oxygen flux and selectivity. These are known as ion transport membranes
(ITM). Conceptual designs were carried out for a hydrogen-refueling station
dispensing 15000 m3/day hydrogen at 350 bar. This route offers a 27% cost
savings compared to trucked-in liquid hydrogen.
1.5.9 Thermal plasma reformer technology can be used for the production
of hydrogen and hydrogen-rich gases from methane and a variety of liquid
fuels. Thermal plasma is characterized by temperatures of 3000-10000oC,
and can be used to accelerate the kinetics of reforming reactions even without
a catalyst. Plasma-reforming systems have been developed and used for
evaluating the potential of this technology for small-scale hydrogen
production. The best steam reforming results to date showed 95% conversion
of methane and projected that the power required can be reduced by about
half.
1.5.10 Hydrogen is currently produced for industrial applications by cracking
carbonaceous fossil fuels. Natural gas reforming is currently the most
efficient, economical and widely used process for production of hydrogen and
has been utilized globally for many decades in the oil refinery and fertilizer
industries. Steam reforming (SMR) has the lowest capital costs of the
hydrogen production technologies with efficiencies in the range 60%–80%.
1.5.11 In spite of efforts to produce hydrogen by processes involving solar
energy, wind energy, nuclear energy and bio-fuels, fossilized carbonaceous
resources and their products remain the most feasible feedstock in the near
term, and for commercial scale production of pure hydrogen, steam reforming
remains the most economic and efficient route.
b) Pyrolysis of Biomass and reformation of bio-oil and gaseous
products
1.5.12 Biomass is a renewable source of energy and is available almost
everywhere on the earth. Hydrogen content in biomass is roughly 6.5% by wt.
Biomass is thermally decomposed / fast pyrolysed in the temperature range of
600 - 10000C at 1-0.5 MPa in an inert atmosphere to form vapors of dark
brown bio-oil (about 85% oxygenated organics and remaining water), other
gaseous products (H2, CH4, CO & CO2) and solid products(mainly charcoal).
The bio-oil and gaseous products are then reformed to produce hydrogen.
The maximum yield of hydrogen can reach up to 90% with the use of Ni-
catalyst at 750-8500C. Alternatively, the phenolic components of the bio-oil
can be extracted with ethyl acetate to produce an adhesive/phenolic resin co-
product; the remaining components can be reformed as in the first option. The
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product gas from both alternatives is purified using a standard Pressure
Swing Adsorption (PSA) system. National Renewable Energy Laboratory
(NREL) U.S.A. has developed a demonstration scale unit for the production of
hydrogen from pyrolysis oil by steam reformation. The pyrolysis oil is also
generated from biomass (such as peanut shells) in a fluidized bed. Slow
pyrolysis gives high char yield and is generally not considered for hydrogen
production.
c) Gasification of Renewable Biomass and its Reformation
1.5.13 Biomass gasification is a sub-stoichiometric combustion process, in
which pyrolysis, oxidation and reduction take place. Pyrolysis products
(volatile matter) further react with char and are reduced to H2, CO, CO2, CH4
and higher hydrocarbons (HHC). In this process, tar is formed, which may
produce tar aerosols and polymerized compounds. Therefore, tar formation is
undesirable. The gasifier may be so appropriately designed to reduce tar
formation. Injection of secondary air is used to reduce tar formation. Indian
Institute of Science (IISc), Bangalore has developed an open-top downdraft
gasifier, in which effects of various parameters like, equivalence ratio (ER),
steam-to-biomass ratio (SBR) residence time- temperature on efficiency are
studied. Ni-based catalysts and alkaline metal oxides are used as gasification
catalysts to improve gas product quality and conversion efficiency. The
syngas yield increased from 353 g per kg of biomass to 828 g per kg of
biomass by varying the pyrolysis temperature from 600 - 10000C.
1.5.14 Internationally, many countries are involved in the development of
biomass gasification technology. The University of British Colombia, Canada
is working on fluidized bed gasification and sorbent based hydrogen
separation unit. The Gas Technology Institute (GTI), Chicago is working on a
the demonstration project for direct generation of hydrogen from a down draft
gasifier using a membrane reactor, The Energy Research Centre of the
Netherlands has developed a pilot plant scale unit of 800 kW th capacity based
on gasification technology. The Technical University of Vienna is developing a
Fast Internally Circulating Fluidized-bed (FICB) technology for steam-blown
gasification of biomass in cooperation with Austrian Energy and Environment
agency. A combined heat and power (CHP) plant (8MW) is in operation since
2002 in Güssing, Austria. Later on, Synthetic Natural Gas (SNG) production
was also demonstrated in a methanation unit, which took a 1 MW SNG
slipstream from the Güssing plant. The targeted production cost of hydrogen
through this method is around US$ 2.5 to 3.5 /kg of hydrogen at large scale.
The Biomass Gasification project of Gothenburg, Sweden aims to construct a
synthetic natural gas (SNG) plant.
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1.5.15 With the development of fuel cell systems in the country, MNRE
focuses on the generation of hydrogen rich syngas through thermo-chemical
conversion of biomass and its purification to fuel cell grade. IISc has recently
concluded a project addressing these aspects. This encouraged work on the
development of a prototype system to generate hydrogen rich syngas using
oxy-steam gasification. The entire process has been optimized to generate a
maximum of about 100 g of hydrogen per kilo gram of biomass. Syngas
composition, hydrogen yield and performance parameters have been
monitored by varying steam to biomass ratio and equivalence ratio. Results
show that using dry biomass with oxy-steam improves the hydrogen yield,
efficiency and syngas with lower heating value (LHV) compared to direct
usage of wet biomass with oxygen. With the current experience of using
biomass, about 70 g of pure hydrogen can be obtained per kg of biomass,
which results in about 15 kg of biomass for every kg of hydrogen generated.
d) Electrolysis of Water
1.5.16 Hydrogen can be generated through electrolysis of water. The water
electrolysis can be carried out in three different ways viz., alkaline water
electrolysis, acidic water (polymer electrolyte membrane based) electrolysis
and high temperature ceramic membranes (solid oxides membranes) water
electrolysis. Polymer electrolyte membrane (PEM) based water electrolysers
are more advantageous than conventional water-alkali electrolysers due to
their ecologically safe nature, production of hydrogen with high purity
(>99.99%) and possibility to produce at high pressure.
1.5.17 The alkaline water electrolysis is a matured technology and is
commercially available in megawatt range. It has a stack life is <90,000 h and
system life of 20-30 years, energy requirement of around 6 kWh per Nm3
hydrogen and efficiency of 60-70%. In the case of PEM based water
electrolysers stack life is <20,000 h and the system life is estimated to be
around 10-20 years. These electrolysers are smaller, cleaner and more
reliable systems than other electrolysers. Alkaline electrolysers are less
expensive than PEM electrolysers due to use of non-noble metal (nickel
based) catalysts, but consume more electricity. The major challenges of
these electrolysers are related to corrosion and poisoning of the electrolysers
by inadvertent incursion of CO2. The largest existing alkaline electrolysis
plants are 160 MW plant in Aswan, Egypt and 22 MW plant operating in Peru
(pressurized operation). The Brown Boveri electrolyser can produce
hydrogen at a rate of about 4-300 m3/h.
1.5.18 The PEM water electrolyser is being deployed for the applications,
where cost is a secondary issue. The membrane material for these
electrolysers is Nafion from DuPont, USA. Besides Du Pont, Asahi Glass,
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Dow Chemicals and others have also developed similar membranes either
based on fluorinated or non-fluorinated polymers, which are commercially
available. The fluorinated polymers have shown good performance for >5000
hours of operation in the fuel cells. However, there are other issues related to
its operation such as increase of cross-permeation of gases with increase in
pressure. As of now small and medium range PEM water electrolysers are
available for laboratory use and other applications. Currently available PEM
water electrolyser systems have a hydrogen production rate that varies from
0.06 to 75 Nm³/h whereas alkaline electrolysers have reached the hydrogen
production rate of 760 Nm³/h.Siemens, FRG plans to build an electrolyser
system to store wind power as hydrogen. The system will have a peak rating
of up to 6 MW.
1.5.19 High temperature water electrolysis uses solid oxide electrolyte and
offers advantage over alkaline and PEM electrolysers in terms of higher
efficiency and lower capital costs. Solid oxide membranes are prepared from
calcium and yttrium stabilised zirconium oxide. These electrolysers are
operated at high temperatures (900–1000°C), which reduces the consumption
of electricity for production of hydrogen by about 30% in comparison to other
electrolysis processes at room temperature. Electricity consumed is about
2.6-3.5 kWh/Nm3 of hydrogen produced.
1.5.20 The Bhabha Atomic Research Centre (BARC), Mumbai has developed
water electrolysers with high current density (4500 A/m2) based on
indigenously developed advanced electrolytic modules incorporating porous
nickel electrodes. A portable electrolyser of 1.5 Nm3/h hydrogen production
capacity and large units of capacities 10 and 30 Nm3 /h hydrogen production
have been developed. BARC has also planned to develop high temperature
steam electrolyser of 1.0 Nm3/h hydrogen production capacity for technology
demonstration purposes. CSIR-CECRI has developed activated nickel
electrode for alkaline electrolyser. PEM water electrolyser of capacity 1.0 and
5.0 Nm3/h were also developed during 2012 and demonstrated with energy
consumption of about 5.75 kWh/Nm3of hydrogen at 5-10 bar pressure. These
technologies have been transferred to M/s. Eastern Electrolysers, New Delhi
for further development. In addition, CSIR-CECRI has also demonstrated
solar power integrated PEM based water electrolyser system of 0.5 Nm3/h
capacity in 2012.The SPIC Science Foundation (SSF), Chennai has
developed PEM based water electrolysers for hydrogen production at the
rates of 0.5 and 1 Nm3/h. In these electrolysers titanium plate was platinised
and used as bipolar plate. The SSF has also developed and demonstrated a
PEM based water electrolyser system with the hydrogen production capacity
of 60.0 lit/h using methanol as the depolariser. The energy consumption for
hydrogen production was 2.0 kWh/Nm3.The Institute of Science and
Technology, JNTU, Hyderabad has developed PEM based water electrolyser
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to produce hydrogen at the rate of 36 L/h using Nafion membrane. The Centre
of Fuel Cell Technology, Chennai (a project of International Advanced
Research Centre for Powder Metallurgy, Hyderabad) has developed and
demonstrated a 1.0 Nm3/h hydrogen production capacity electrolyser using
similar concept but with much lower energy consumption of 1.40kWh/Nm3. It
also demonstrated for the first time the use of carbon based materials in its
construction and thus redcuing the capaital cost tredomnously. M/s. MVS
Engineering Ltd, New Delhi are offering PEM water electrolyser technology on
turnkey basis in partnership with Proton Onsite (USA) for hydrogen
generation. Recently, such a system has been installed at the Indian Oil’s
R&D Centre, Faridabad. A number of other companies are also reported to
have commercialised alkaline water electrolyser for various industrial
applications. In general, the production of hydrogen through electrolysis of
water is a highly energy intensive (4.5-6.5 kWh/Nm3). High energy
consumption coupled with high capital investment is the reason, why water
electrolysis technology is not preferred in India for commercial purposes.
1.5.21 Acid and alkali based solid polymer electrolytes have been
developed. Alkali based electrolytes use non-noble catalysts, but face
challenges such as chemical stability in the electrochemical system. The
electrolysers using acid based solid polymer electrolyte may be deployed on a
small scale for distributed hydrogen production systems both in industry as
well as remote areas for different applications. It is suggested to setup
hydrogen production plants based on presently available technology, which
can be manufactured in India and then conventional electrolyser may be
replaced by the SPE based electrolysers in a phased manner. This will ensure
the successful deployment of technology in the times to come. The estimated
cost per kg of hydrogen is about $ 8.94, when produced on a 1 MW level.
1.5.22 The strategy to bridge the gap may be planned by identifying projects
and the institutions to work in the relevant specialized areas and demonstrate
their prototypes. Foreign collaborations may be solicited in specific areas.
After successful demonstration of the prototypes, the R&D institutions may
work with the industry through PPP Model for commercialization of the
technology. Except the electrochemical stack, couple of Indian PSUs have
core strength for manufacturing majority of subsystems and are very much
capable in system engineering. Imported electrolyser stacks in different
combinations may also be used and integration can be carried in the country.
e) Bio-Hydrogen Process
1.5.23 The bio-hydrogen production may be an economical way of hydrogen
production on the ground that the process takes place at ambient temperature
and atmospheric pressure; while other processes are carried out at higher
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temperatures & pressures. The major biological processes for hydrogen
production are bio-photolysis of water by algae (if the algae is deprived of
sulphur, it will switch from the production of oxygen, i.e. normal
photosynthesis, to the production of hydrogen), dark and photo-fermentation
of organic materials, usually carbohydrates by bacteria. One of the major
problems faced by photo-fermentative reactors is the light shading effect
generated by accumulation of pigment in the photo-fermentative microbes.
Moreover, the rate of hydrogen production in bio-hydrogen reactors is also
considerably low when compared with dark fermentation. Sequential dark and
photo-fermentation process is a new approach for bio-hydrogen production.
Dark fermentation reactions do not require light energy, so they are capable of
constantly producing hydrogen from organic compounds present in
wastewater throughout the day and night. Among all the biological hydrogen
production processes, dark fermentation shows highest hydrogen production
rates. This process holds promise for commercialization. Carbohydrate rich,
nitrogen deficient solid wastes such as cellulose and starch containing
agricultural and food industry wastes and some food industry wastewaters
such as cheese whey, olive mill and bakers’ yeast industry waste water can
be used for hydrogen production by using suitable bio-process technologies.
Utilization of aforementioned wastes for hydrogen production provides
inexpensive energy generation with simultaneous waste treatment. A
prototype hydrogen bioreactor using waste as a feedstock is in operation at
Welch's grape juice factory in North East Pennsylvania, USA. Another two-
stage process where bio-hydrogen production process was integrated with
bio-methanation is also being considered as a feasible option for improvement
of gaseous energy recovery. This mixture of bio-hydrogen and bio-methane
may be named as “hymet”.
1.5.24 Major contributors in biohydrogen production research are from United
States of America, Canada, Malasiya, Indonesia, Thailand, China and India.
Different microbes have been discovered in different parts of the world, each
having unique hydrogen production ability. Shri AMM Murugappa Chettiar
Research Centre, (MCRC), Chennai was involved in the development of
hydrogen production through biological process from sugar and distillery
wastes (effluents of M/s. E.I.D. Parry Ltd., at Nellikuppam, Tamilnadu). The
Center has designed and developed a 125 m3 bioreactor, which produced
18,000 liters of gas per hour with about 60% hydrogen mixed largely with CO2
and CO. Mesophilic and thermophilic species were identified for hydrogen
production. Indian Institute of Technology Kharagpur and Indian Institute of
Chemical Technology, Hyderabad are currently setting up bio-reactors of
10m3capacity each based on distillery effluent and kitchen waste respectively
and are expected to provide hydrogen yield of 30-50 m3 / day. For bio-
hydrogen to be considered as renewable energy source, it should be
produced from renewable raw materials like waste materials. Internationally
12
very few studies are available on commercial level units for bio-hydrogen
production. Integration of bio-hydrogen with fuel cell was first mooted in 2012.
This concept still needs a serious consideration since this technology is
capable of producing hydrogen in a decentralized manner.
1.5.25 Hydrogen can be recovered equivalent to only 20 to 30 % of total
energy through dark fermentation and therefore has limitations in
commercialization, even though this process can be integrated with photo-
fermentation. Theoretically, 12 moles of hydrogen /mole of glucose can be
recovered from integrated dark and photo fermentation reactors but due to
scaling up problem of photo-fermentation such two-stage process cannot
commercialised. The dark fermentation for hydrogen production can be
commercialised, if it is integrated with biomethantion process. The spent
media of the dark fermentation is rich in volatile fatty acids and would be an
ideal substrate for methanogens. The integration of these two processes
might lead to 50-60% gaseous energy recovery. Most attractive point of such
process is that the reactor used for hydrogen production could be used for
bio-methanation also, thus separate reactors are not required. Biohymet
production could be envisioned as renewable source of energy only, when it
would be produced from renewable sources.
f) Thermochemical splitting of water
1.5.26 Water can be dissociated at very high temperatures into hydrogen and
oxygen through thermochemical splitting of water. A catalyst is required to
make the process operate at feasible temperatures. The required energy can
be either provided by nuclear energy or by solar energy, or by hybrid systems
including solar and nuclear energy. More than 356 thermo-chemical cycles
have been conceived which can be used for water splitting. Around a dozen
of these cycles such as the iron oxide cycle, cerium(IV) oxide-cerium(III) oxide
cycle, zinc-zinc oxide cycle, sulfur-iodine cycle, copper-chlorine cycle and
hybrid sulfur cycle are under research/in testing phase. The iodine-sulphur (I-
S) cycle is one of the most promising and efficient thermo-chemical water
splitting technologies for the mass production of hydrogen, on which BARC,
Trombay, Mumbai is working.
1.5.27 The I-S closed loop glass system has been operated continuously for a
period of 20 hours at hydrogen production rate of 30 Lph. India is the 5th
country to achieve I-S closed loop operation in glass system, after USA
(1980), Japan (2004), China (2010) and South Korea (2009). USA aims to
demonstrate commercial scale production of hydrogen using nuclear energy
by 2017. European Union started working in this direction in 2004 with the
objective to evaluate the potential of thermo-chemical processes, focusing on
the I-S cycle which is to be compared with the Westinghouse hybrid (HyS)
13
cycle in view of the 2015 target for reduction of CO2 emissions from fossil
fuels by more than 25% and hydrogen production cost of less than €2/kg. It
has been found that hydrogen production costs based on small plants is most
favorable using solar energy, while nuclear energy based plants are most
economical at high power levels (> 300 MW th); hybrid systems may have their
niche in the midrange of 100 to 300 MW th. Canada is investigating copper–
chlorine family of thermo-chemical cycles with energy provided by the
Canadian Super Critical Water Reactor and use of direct resistive heating of
catalysts for SO3 decomposition in the I-S process. Japan has recently
initiated R&D activities on the thermo-chemical cycles based on the UT-3 and
I-S processes for hydrogen production and successfully achieved the
operation of a bench-scale facility for hydrogen production at the rate of 30
Nl/h in a continuous closed I-S cycle operation over one week. While the
efficiency was only ~10% for the bench-scale plant, the goal for the pilot plant
is ~40%. In 2005, Japan have already initiated the activity to design and
construct a pilot plant for hydrogen production at the rate of 30 Nm3/h under
the simulated conditions of a nuclear reactor.
1.5.28 The Republic of Korea has targeted for 25 % (3 Mt/year) of the total
hydrogen to be supplied by advanced 50 nuclear reactors by 2040. Korea
launched its nuclear hydrogen program in 2004 targeting (i) generation of
hydrogen for fuel cell applications for electricity generation, passenger
vehicles, and domestic power and heating, and (ii) lowering hydrogen costs
and improving efficiency of the related processes. Under this programme an
underground VHT reactor of 200 MW thermal output is to be coupled with an
I-S cycle to generate hydrogen from water. In 2005 People’s Republic of
China initiated work on a demonstration project on ‘High Temperature Reactor
– Pebble Module’. Both the I-S thermo-chemical cycle and high temperature
steam electrolysis are selected as the potential processes for nuclear
hydrogen production. The target has been set for commercialization of
nuclear hydrogen production by 2020.
1.5.29 The Bhabha Atomic Research Centre has successfully demonstrated I-
S process in closed loop operation in glass/quartz material in the laboratory. It
is further planned to demonstrate closed loop operation in metallic
construction. Other institutes / organisations will also be roped in depending
upon their capabilities. Their broad plan is:
(i) Design and Demonstration of Atmospheric pressure operation all
Metal closed loop system (AMCL).
(ii) High pressure operation Bunsen reactor system has been designed
and its commissioning is underway.
(iii) Design and demonstration of high pressure Sulfuric acid
decomposition system.
14
(iv) Design and demonstration of Hydriodic acid distillation and
decomposition system.
(v) Integration of all three high pressure systems to demonstrate, High
pressure closed loop process.
1.5.30 The ONGC Energy Centre (OEC) started working on the three
thermochemical processes such as Cu-Cl closed loop cycle, I-S closed loop
cycle and I-S open loop cycle at engineering scale and all these processes
will be compared before taking-up at the commercial level. In view of
expensive and corrosive nature of materials used in these processes, OEC
has planned to study and evaluate alternative materials. New plants may
then be designed based on this evaluation of the alternative materials.
CSMCRI, Bhavnagar has been involved in the ‘development of membranes’;
IIP Dehradun is engaged in the ‘development of partially open-loop I-S cycle
involving H2S incineration and experimental studies on Bunsen Reaction & HI
decomposition’; IIT-Delhi is working on “prolonged stability tests of catalysts
for HI decomposition reaction of I-S cycle.
1.5.31 Photo-catalytic and photo-electrochemical routes for hydrogen
production are also being explored globally by several research groups. In
India also some groups, namely, Indian Institute of Chemical Technology,
Hyderabad; Institute of Minerals and Materials Technology, Bhubaneswar;
Yogi Vemana University, Kadapa; SRM University; Kancheepuram, Shiksha
‘O’ Anusandhan University, Bhubaneswar and Centre for Materials for
Electronics Technology, Pune are active in this area. Efforts are being made
to come out with effective and robust photo-catalysts and photo-
electrocatalysts, electrode materials and materials for reactors. Till date no
large scale unit has been successfully designed and demonstrated.
Concerted intensive efforts, however, are required to generate basic
information and knowhow to take this area to the production for decentralized
applications.
1.5.32 In photo-electrochemical water splitting, hydrogen is produced from
water using sunlight and specialized semiconductors called photo-
electrochemical materials. The Institute of Minerals and Materials Technology
Bhubaneswar developed functional hybrid nano-structures for photo-
electrochemical water splitting. The different photo-catalytic materials were
developed for hydrogen production through water splitting. The developed
materials yielded hydrogen e.g. 800-1000 mg hydrogen /batch with CdS
photo-electrodes and CdS nano-crystal powder photo-catalysts, 4087 µmol
hydrogen/h/g with 0.28 wt% Poly (3-hexylthiophene-2,5-diyl) (P3HT) modified
CdS and 11,901 µmol hydrogen/h/g with CdS-NaNbO3 core-shell nano-rods.
Thus, CdS-NaNbO3 core-shell nano-rods was found to give maximum
hydrogen production.
15
g) Other Technologies
1.5.33 Presently, Hydrogen Production by non-thermal plasma assisted direct
decomposition of hydrogen sulphide is at research and development stage
and no commercial technology is available globally. Among the several
techniques tested for the production of hydrogen, Idemitsu Kosan Hybrid
(IKC) electrolysis process consumes 3.6 kWh/Nm3 hydrogen, whereas steam
reforming of methane, (the traditional approach for hydrogen production)
demands still higher energy of 4.3 kWh/Nm3 hydrogen. 40% conversion of
hydrogen sulphide by thermal decomposition can be achieved at temperature
~ 1500K. Most of the research in this area in the country has been focused
on catalytic/ photocatalytic decomposition of hydrogen sulphide. Hydrogen
sulphide under visible light to generate hydrogen is an attractive route of solar
energy conversion, because hydrogen is 100% environmentally clean fuel in
its cycles of generation and utilization. The Indian Institute of Technology
Hyderabad developed the process of non-thermal plasma assisted direct
decomposition of hydrogen sulphide into hydrogen and sulphur. Hydrogen
production of 0.5 litre/minute was achieved in the laboratory. The reaction
conditions can be still improved to decrease the energy consumption.
1.5.34 For the photo-splitting of hydrogen sulphide into hydrogen, extensive
work has been carried out for the development of ultraviolet driven
photocatalyst for water and hydrogen sulphide splitting. There is need to
develop prototype batch photo-reactor for hydrogen production from hydrogen
sulphide using solar energy and their field trials using gas emitted at refinery
site. Internationally, many groups in Japan, Korea, U.S, Europe are working
on development of active photo-catalysts for hydrogen generation under
visible light irradiation. The National Institute of Advanced Industrial Science
and Technology, Japan demonstrated first time in 2001 direct splitting of
water by visible light over an In1.xNixTaO4photocatalyst. Nationally, a few
groups are working on photocatalytic splitting of water and hydrogen and
hydrogen sulphide into hydrogen under visible light. BARC is working on
photocatalytic degradation of nuclear waste as well as water purification. IISc,
Bangalore is working on TiO2 based photocatalysts for organic waste
degradation. IITs, Mumbai and Madras, CECRI, Karaikudi, IICT, Hyderabad
and some universities in India are working on photodecomposition of organic
pollutants. The Centre for Materials for Electronics Technologies (C-MET),
Pune is also working on hydrogen generation by photocatalytic decomposition
of toxic hydrogen sulphide and achieved hydrogen production from hydrogen
sulphide at the rate of 8182.8 and 7616.4 µmol/h/g obtained from
nanostructured ZnIn2S4 and CdIn2S4, respectively in presence of sunlight. This
design is useful for continuous operation at large scale.
16
1.6.0 Suggested Action Plan
1.6.1 Based on the gap analysis undertaken between international and
national state of art of technologies and recommendations to fill the gap by
undertaking the projects as classified in the three broad categories: (a)
Mission Mode (for the technologies, which are mature or near maturity for
commercialization and with the participation of the industry); (b) Research &
Development Mode (for the technologies, which are at the stage of prototype
development, their demonstration as a proof of concept and preferably with
Industry participation); and (c) Basic / Fundamental Research Mode (for
advanced research on new materials and processes), the Action Plan for
hydrogen production in the country has been devised as following:
1.6.2 The unutilized (around 6600 tonnes) by-product hydrogen from the
Chlor-Alkali Units / Refineries may be used directly for the generation of
power / in transportation applications (vehicles) based on IC engine
technology. This hydrogen may further be purified (if required) for stationary
power generation and on-board application in vehicles / material handling
systems based on fuel cell technology. To utilize this hydrogen requisite
power generating system / purification unit / compression system to fill
cylinders for on-board application of hydrogen in vehicles / material handling
vehicles (based on fuel cell technology) need to be set-up. The activity is to
be completed by 2018.
1.6.3 Hydrogen has been produced from the conventional sources i.e.
carbonaceous fuels like natural gas, coal etc. Hydrogen production by
electrolysis, methanol or ammonia cracking is preferred for small, constant or
intermittent requirements of hydrogen in food, electronics and pharmaceutical
industries, while for larger capacities steam reforming of hydrocarbons /syn
gas is preferred. Renewable-based processes like solar- or wind-driven
electrolysis and photo-biological water splitting hold great promise for clean
hydrogen production; however, advances must still be made before these
technologies can be economically competitive. Thus, hydrogen production
may be continued from the conventional (carbonaceous) fuels through the
most competitive process namely auto-thermal reforming (steam reforming
and partial oxidation) process till the technologies for hydrogen production
from renewable sources become economically competitive. Scaling-up of the
process of catalytic decomposition of natural gas for the production of H-CNG
for the use in H-CNG fuelled vehicles (up to 2019), Development &
demonstration of hydrogen production by Auto-thermal Process (up to 2020)
and Basic / Fundamental Research for dissociation of gaseous hydrocarbon
fuels to hydrogen using solar energy (up to 2022) may be carried out.
17
1.6.4 Biomass has been identified as potential source of renewable energy
for hydrogen production. Biomass is gasified to hydrogen rich syngas, which
may be reformed and purified to yield pure / near pure hydrogen. The
technology of oxy-steam gasification of biomass for hydrogen products has
been developed at a small pilot scale (2 kg/h) by the Indian Institute of
Science, Bangalore. This may be promising technology for distributed
hydrogen production. However, there are challenges associated with
purification of hydrogen and scaling up. Research and development for
hydrogen production by gasification of biomass may, therefore, be carried out
including demonstration of technology at pilot scale (up to 2020).
1.6.5 Pure hydrogen may be obtained by electrolysis for fuel cells
applications. The electrolyser system consists of various sub-systems. India is
capable in system engineering and has core strength for manufacturing
majority of sub-systems except electrochemical stack. Imported electrolyser
stacks may be used with the indigenously developed sub-systems. The
Institutions / Industry may be identified to work in PPP Model for
commercialization of the balance of plant and simultaneously, the technology
for the production of stack may be procured or developed indigenously. Solid
polymer electrolyser (SPE) with 20,000 hours of operation is desirable and
may have membranes based alkaline water electrolysis system integrated
with solar photovoltaic system. For the immediate availability of hydrogen
onsite, hydrogen may be produced by deploying solar energy powered Acid /
Alkali based electrolysis systems based on available technology.
Simultanously, development of (i) electrolysers based on indigenous acid
based SPE (ii) alternate alkaline membrane up to 2018 (iii) alkaline 1 & 5
Nm3/h high temperature steam solid polymer water electrolyser (up to 2020)
may be done and demonstrated and replaced old systems by the newly
developed systems. Hydrogen production system by splitting water using
renewable energies such as solar energy, wind energy and hybrid systems
including electrolysis, photo-catalysis and photo-electro-catalysis may also be
developed and demonstrated(up to 2022).
1.6.6 Hydrogen may be produced through dark-fermentation followed by the
photo- fermentation of solid waste from agriculture & food industry and liquid
waste from food industry. The integrated process is difficult to commercialise
in view of the problems associated with the photo-fermentative reactors.
Therefore, dark fermentation followed by bio-methanation may be studied,
which can recover 50 - 60% gaseous energy from the waste. Only one reactor
may be required for both processes – firstly, hydrogen production and
subsequently, bio-methanation. The mixture of hydrogen and methane, so
produced, is known as bio-hymet. The production of bio-hymet could be
envisioned as renewable source of energy. This activity has been proposed
to be taken up in Research, Development and Demonstration Mode up to
18
2019. Energy balance and process economic aspects may also be studied.
Biological hydrogen production projects may also be taken up for
demonstration in niche areas.
1.6.7 Another path for hydrogen economy has been suggested by the
integration of fuel cell system with the bio-hydrogen production system. Such
setups may be put strategically near to those places where supply of
feedstock is easily available in adequate quantities. The electricity generated
by such system may be used to electrify villages in a decentralized manner. It
is suggested to take-up such activities in Mission Mode up to 2022.
1.6.8 The Bhabha Atomic Research Centre is engaged in the development
of I-S technology in-house. This process in closed loop operation has been
successfully demonstrated in glass/quartz reactor. Further, it has been
planned to demonstrate closed loop operation of I-S in metallic reactor.
ONGC Energy Centre is also working on I-S process in collaboration with IIT-
Delhi, ICT Mumbai and CECRI, Karaikudi on both I-S open & closed loop and
Cu-Cl cycles. Hydrogen generation @ 27 LPH has been achieved through
Cu-Cl process under specified operating conditions. It is suggested to
continue these activities using solar / nuclear heat in Mission Mode up to
2022.
1.6.9 Hydrogen production by water splitting through photolysis using solar
energy may be undertaken upto 2022 in Mission Mode.
1.6.10 Other innovative method for hydrogen production, like hydrogen
production by non-thermal plasma assisted direct decomposition of hydrogen
sulphide, Photo-splitting of Hydrogen Sulphide including developmental effort
for reduction in energy consumption for hydrogen production (up to 2022).
1.6.11 The total requirement of budget would be around Rs.285 Crore upto
2022.
1.7 Financial Projections for the Mission Mode, Research and
Development Mode and Basic / Fundamental Research Mode projects are
given as under:
19
S. No.
Name of Project Estimated Cost Rupees in
Crore
A. Mission Mode Projects
1 Setting-up of purification unit / compression system to fill cylinders for power generating system / on-board application of hydrogen in vehicles / material handling vehicles (based on fuel cell technology) to utilize surplus hydrogen from the Chlor-Alkali Units / Refineries (up to 2019).
20
2 Scaling-up of the process of partial reforming of natural gas to produce H-CNG for H-CNG fuelled vehicles (up to 2019)
40
3 Development and demonstration of biological hydrogen production from different kinds of wastes on bench scale, pilot scale and commercial production (up to 2022).
20
4 Hydrogen production by water splitting through photolysis using solar energy (up to 2022).
40
5 Demonstration of closed loop operation of I-S in metallic reactor and both I-S open & closed loop process and Cu-Cl cycle using solar / nuclear heat in Mission Mode (up to 2022).
50
Sub-Total A 170
B. Research and Development Projects
6 Hydrogen production by auto-thermal process (up to 2020)
20
7 Hydrogen production by gasification of biomass including demonstration of technology at pilot scale (up to 2020)
10
8 Development and demonstration of electrolyser based on indigenous acid based SPE and alternate alkaline membrane and its deployment to replace old systems (up to 2019).
10
9 Development and demonstration of alkaline 1 & 5 Nm3/h high temperature steam solid polymer water electrolyser and its deployment to replace old systems (up to 2020)
10
10 Development & demonstration of efficient alkaline water electrolyser (upto 2018)
10
11 Development and demonstration of hydrogen production by splitting water using renewable energies such as solar energy, wind energy and hybrid systems including electrolysis, photo-catalysis and photo-electro-catalysis (up to 2022)
10
12 Hydrogen production by reformation of bio-oil obtained from fast pyrolysis of biomass (up to
5
20
2022).
13 Development of technology for production of syn-gas (CO+H2) and hydrogen from reformation of natural gas / biogas using solar energy (up to 2022).
5
14 Integration of large capacity electrolysers with wind / solar power units, which is not in a position to evacuate power to grid, for generation of hydrogen and its storage (up to 2022).
5
Sub-Total B 85
C. Basic / Fundamental Research Projects
15 Dissociation of gaseous hydrocarbon fuels to hydrogen using solar energy (up to 2022)
10
16 Other innovative method for hydrogen production like hydrogen production by non-thermal plasma assisted direct decomposition of hydrogen sulphide, Photo-splitting of Hydrogen Sulphide including developmental effort for reduction in energy consumption for hydrogen production(up to 2022)
20
Sub-Total C 30
Grand Total
285
21
ACTIVITIES ON HYDROGEN PRODUCTION
MMP: Mission Mode Projects; RD&DP: Research & Development Projects; B/FRP: Basic / Fundamental Research Projects
Sl.
No. Category of Projects
Time Frame (Year) Financial
Outlay
(Rs. in Crore) 2016 2017 2018 2019 2020 2021 2022
1
Mission Mode Projects
20
40
20
40
50
Setting-up of purification unit / compression
system to fill cylinders to utilize surplus
hydrogen from the Chlor-Alkali Units /
Refineries
Scaling-up of the process of partial reforming of
natural gas for the production of H-CNG
Demonstration of closed loop operation of I-S in metallic reactor and both I-S open & closed loop process and Cu-Cl cycle using solar / nuclear heat
SUB-TOTAL 170
Development and demonstration of biological hydrogen production from different kinds of wastes
Phase I Bench Scale
Phase II Pilot Scale
Phase III Commercial Production
Hydrogen production by water splitting through photolysis using solar energy
22
2
Research, Development
& Demonstration
20
10
10
10
10
10 5
5 5
Hydrogen production by gasification of biomass including
demonstration of technology at pilot scale
Development, and demonstration of
electrolyser with indigenous acid based SPE &
alternate alkaline membrane and its
deployment to replace old systems
Development and demonstration of alkaline 1 & 5 Nm3/h high temperature
steam solid polymer water electrolyser and its deployment to replace old
systems
Hydrogen production by Auto-thermal Process
Development of technology for production of syn-gas (CO+H2) and hydrogen from
reformation of natural gas / biogas using solar energy.
Integration of large capacity electrolysers with wind / solar power units, which is not in a
position to evacuate power to grid, for generation of hydrogen and its storage
SUB-TOTAL 85
Development and demonstration of Hydrogen production by splitting water using
renewable energies
Hydrogen production by reformation of bio-oil obtained from fast pyrolysis of biomass
Development & demonstration of
efficient alkaline water electrolyser
23
3.
Basic / Fundamental
Research Projects
10
20
Other innovative method for hydrogen production like hydrogen production by non-
thermal plasma assisted direct decomposition of hydrogen sulphide, Photo-splitting of
Hydrogen Sulphide including developmental effort for reduction in energy consumption
for hydrogen production
SUB-TOTAL 30
GRAND TOTAL 285
Dissociation of gaseous hydrocarbon fuels to hydrogen using solar energy
27
2.0 Introduction
2.1 Human being’s dependence on fossil fuels has made a deep impact on
its reserves and natural climate. This has led to exhaustion of fossil fuels,
emission of pollutants, and greenhouse gases responsible for global warming.
It has been recognized that the crude petroleum oil output by the Organisation
of the Petroleum Exporting Countries (OPEC) would not be able to meet the
energy demands beyond 2045. To address the above issues, hydrogen is
considered as one of the potential energy carrier for the future that is not only
clean but also environmentally sustainable. Hydrogen may replace petrol and
diesel used in the automobiles and even coal for large scale power
generation. Presently, hydrogen is produced for non-energy applications and
‘quantum increase’ in hydrogen production will be required to enable its mass
scale utilization as a fuel. To have sustainable hydrogen production, the
energy and raw materials needed for this purpose ought to be renewable in
nature. There are various methods which may be employed for generating
hydrogen from renewable and non-renewable resources. However, the
challenge lies in the production of hydrogen in a cost effective manner. As per
US DOE, more than 50 million tonnes of hydrogen was produced globally in
2010, of which 46.3% was consumed for petroleum recovery and refining;
44.5% for ammonia production; 3.7% for methanol production; 2.0% for metal
production and fabrication; 1.5% for electronics; 1.0% for food industry and
1.0% for other applications. About 95 % of the current hydrogen requirements
are produced through fossil fuel sources. Currently, the agricultural sector is
the largest user of hydrogen in the form of nitrogenous fertilizers, with 49% of
hydrogen being used for ammonia production. Being a clean energy source,
its future widespread use as fuel is likely to be in the transport and also in
distributed power generation sectors. Hydrogen may indeed emerge to be a
turning point for our nation, which is dependent heavily on the imported
petroleum crude and natural gas for meeting its energy needs. Development,
demonstration and commercialization of appropriate hydrogen production
technologies and systems are, therefore, essential in the country, since these
have advanced significantly world over.
2.2 Molecular hydrogen is not available on the earth in convenient natural
reservoirs. Most hydrogen on the earth is bonded to oxygen in water and to
carbon in live or dead and/or fossilized biomass. Currently manufacture of
elemental hydrogen requires consumption of energy generated from a fossil
or alternative sources. It produces carbon dioxide. Decomposition of water
requires electrical or heat input, generated from some primary energy source
(fossil fuel, nuclear power or a renewable energy- solar, wind, hydro-
electricity, etc.). The energy provided by the energy source essentially
provides all of the energy that is available in the hydrogen fuel.
28
2.3 Hydrogen may be produced from a variety of carbonaceous feed-
stocks and/or water using a variety of technologies. Coal, natural gas,
petroleum fractions and biomass can be converted to hydrogen through
pyrolysis / gasification and reforming using several technologies like steam
methane reforming, partial oxidation / auto-thermal reforming. About 95 % of
the current hydrogen requirements is met from fossil fuel sources.
2.3.1 Steam Methane Reforming (SMR) is the most common, well-
developed and fully commercialised process. It is the least expensive method
of producing hydrogen; almost 48% of the world’s hydrogen is produced from
SMR. The reforming reaction between steam and hydrocarbons is highly
endothermic and is carried out in presence of specially formulated nickel
catalyst contained in vertical tubes situated in the radiant section of the
reformer. The SMR process is popular because natural gas, commonly used
feedstock has high hydrogen content (four hydrogen atoms per carbon atom)
and distribution network for the natural gas already exists. The simplified
chemical reactions are:
CH4 + H2O = CO + 3H2 ∆ H = + 206 kJ/mol (for methane)
CO + H2O = CO2 + H2 ∆ H = - 41 kJ/mol (CO shift reaction)
The Pressure Swing Adsorption (PSA) purification unit separates
hydrogen from mixture of product gases by adsorption of CO, CO2 and CH4.
This process is commonly used to supply large quantities of hydrogen gas to
oil refineries, and ammonia and methanol plants.
Cost of hydrogen production through SMR technology is highly
dependent on the scale of production. Large capacity modern SMR hydrogen
plants have been constructed with hydrogen generation capacities exceeding
480,000 kg hydrogen/day. These large hydrogen plants typically are co-
located with the end users in order to reduce hydrogen gas transportation and
storage costs. In addition, SMR technology is also scalable to smaller end-use
applications. SMR can also be applied to other hydrocarbons such as ethane
and naphtha. Heavier feed-stocks, however, cannot be used, because they
may contain impurities and the feed to the reformer must be in vapour form.
Other processes such as partial oxidation (POX) are more efficient with higher
hydrocarbons.
2.3.2 Hydrogen production from coal gasification is also a well-established
commercial technology, but is only competitive with SMR, where oil and/or
natural gas are expensive. Three primary types of gasifiers are used: fixed
bed, fluidized bed, and entrained flow. Because there are significant coal
reserves in many areas of the world, coal could replace natural gas and oil as
29
the primary feedstock for hydrogen production. However, this technology has
environmental impacts (e.g., feedstock procurement) that may prove to be a
significant impediment in the future.
2.3.3 Non-catalytic partial oxidation of a hydrogen-rich feedstock (such as
natural gas, coal, residue oil, petroleum coke, or biomass) is another pathway
for hydrogen production. With natural gas as a feedstock, the partial oxidation
process typically produces hydrogen at a faster rate than SMR, but it
produces less hydrogen from the same quantity of feedstock. The overall
efficiency of this process (50%) is less than that of SMR (65%-75%) and pure
oxygen is required. Two commercial technologies for this conversion are
available (i) Texaco Gasification Process, and (ii) Shell Gasification Process.
As a result of increasing natural gas prices, further development of natural
gas partial oxidation technology has been slowed down. The use of a solid
fuel like coal is also possible, through gasification, to produce a synthetic gas
(syngas) that can then be used in a partial oxidation process to obtain
hydrogen as product.
2.3.4 Like gasification of coal, biomass may also be gasified using a variety
of methods, primarily indirect and direct gasification. Indirect gasification uses
a medium such as sand to transfer heat from the char combustor to the
gasification vessel. In direct gasification heat is supplied to the gasification
vessel by the combustion of a portion of the feed biomass. In general,
hydrogen produced via direct gasification is expected to cost slightly more
(i.e., 5%) than that from the indirect mode.
2.3.5 In Biomass pyrolysis, biomass may be thermally decomposed at a
high temperature (in the range of 600-10000C) in an inert atmosphere to form
a bio-oil composed of about 85% oxygenated organics and remaining water.
The bio-oil is then steam reformed using conventional technology to produce
hydrogen. Alternatively, the phenolic components of the bio-oil can be
extracted with ethyl acetate to produce an adhesive/phenolic resin as a co-
product; the remaining components can be reformed as in the first option. The
product gas from both alternatives is purified using a standard pressure swing
adsorption (PSA) system.
2.3.6 The Kvaerner-process or Kvaerner carbon black & hydrogen process
(CB&H) is a method, developed in the 1980s by a Norwegian company for the
production of hydrogen from hydrocarbons (CnHm), such as methane, natural
gas and biogas. Of the available energy of the feed, approximately 48% is
contained in the hydrogen, 40% is contained in activated carbon and 10% in
the superheated steam.
30
2.4 Electrolysis of Water
The Electrolysis of water uses electrical energy to split water molecules
into hydrogen and oxygen. Large-scale electrolysis of brine (saltwater) has
been commercialised for chemical applications. Some small-scale electrolysis
systems also supply hydrogen for high-purity chemical applications, although
for most medium- and small-scale applications of hydrogen fuels, electrolysis
is cost-prohibitive. For renewable technologies, the capital costs dominate.
The cost of the electricity is a major concern because it is three to five times
more expensive as “feedstock” than fossil fuels. In fact, the high cost of the
electricity is the driving force behind the development of high-temperature
steam electrolysis. In this process, some of the energy driving the process
can be supplied in the form of steam instead of electricity. For example, at
1000°C, more than 40% of the energy required could be supplied as heat.
Current best process to have an efficiency of 50 - 80% and 1 kg of
hydrogen with specific energy of 143 MJ/kg (about 40 kWh/kg) requires 50 -
79 kWh electricity. At the cost of electricity as $0.08/kWh, hydrogen from
electrolysis would cost $4.00/kg hydrogen, which is 3 to 10 times the price of
hydrogen obtained from steam reforming of natural gas. The price difference
is due to the efficiency of direct conversion of fossil fuels to produce
hydrogen, rather than burning fuel to produce electricity. Hydrogen from
natural gas, used to replace e.g. gasoline, emits more CO2 than the gasoline it
would replace, and so is of no help in reducing greenhouse gases.
2.4.1 High Pressure Electrolysis
High pressure electrolysis is the electrolysis of water by decomposition
of water (H2O) into oxygen (O2) and hydrogen gas (H2) by means of an
electric current being passed through the water. This differs with the standard
electrolyser in terms of the hydrogen output at around 120-200 bar (1740-
2900 psi). By pressurizing the hydrogen in the electrolyser the need for an
external hydrogen compressor is eliminated, the average energy consumption
for internal compression is around 3%.
2.4.2 High Temperature Electrolysis
Hydrogen can be generated from energy supplied in the form of heat
(950–1000 °C) and electricity through High Temperature Electrolysis (HTE).
The electricity and heat generated through a nuclear reactor could be used for
splitting hydrogen from water. Research into high-temperature nuclear
reactors may eventually lead to a hydrogen supply that is cost-competitive
with natural gas-steam reforming. General Atomics predicts that hydrogen
produced in a High Temperature Gas Cooled Reactor (HTGR) would cost
31
$1.53/kg. In 2003, steam reforming of natural gas yielded hydrogen at
$1.40/kg. HTE has been demonstrated for hydrogen production at laboratory
scale (with a product having calorific value of 108 MJ (thermal) per kg) but not
at a commercial scale. This is lower-quality "commercial" grade Hydrogen,
which is unsuitable to use in fuel cells.
2.5 Photo-electrochemical Water Splitting
Using electricity produced by photovoltaic systems offers the cleanest
way to produce hydrogen. Water is broken into hydrogen and oxygen by
electrolysis—a photo-electrochemical cell (PEC) process which is also named
artificial photosynthesis. Research aimed toward developing higher-efficiency
multi-junction cell technology is underway by the photovoltaic industry. If this
process is assisted by photo-catalysts suspended directly in water instead of
using photovoltaic and an electrolytic system, the reaction is in just one step,
which can improve efficiency.
2.6 In photo-electro-catalytic production, a gold electrode is covered in
layers of indium phosphide (InP) nanoparticles and an iron-sulphur complex is
introduced into the layered arrangement, which when submerged in water and
irradiated with light under small electric current, produces hydrogen with an
efficiency of about 60%. The electricity production itself involves large
transformation losses, however, the efficiency of hydrogen production through
electrolysis relative to the primary energy content of the fuel input to
generation would be significantly lower. In certain cases, it may be
economical to use off-peak electricity, if it is priced well below the average
electricity price for the day; however, such market applications would have to
be balanced with other potential electricity supplies, the cost versus benefits
of appropriate metering and rate design, and the implied reduction in
utilization of the electrolysis unit, as described above. The development of
such an application could also support other technologies, such as plug-in
hybrid electric vehicles.
2.7 Hydrogen through Thermal Splitting of Water:
2.7.1 Concentrated Solar Thermal Energy: Very high temperatures are
required to dissociate water into hydrogen and oxygen. A catalyst is required
to make the process operate at feasible temperatures. Heating the water can
be achieved through the use of concentrating solar power. Hydrosol-II is a
100-kilowatt pilot plant in Spain, which uses sunlight to obtain the required
800 - 1,2000C to heat water. It has been in operation since 2008. The design
of this pilot plant is based on a modular concept. As a result, it may be
possible that this technology could be readily scaled up to the megawatt
32
range by multiplying the available reactor units and by connecting the plant to
heliostat fields (fields of sun-tracking mirrors) of a suitable size.
2.7.2 A promising long-term technology is the use of concentrated solar
energy for hydrogen production via electrolysis. Two primary process
configurations are used with this method. In the first, ambient temperature
electrolysis, concentrated solar energy is used to generate alternating current
(AC) electricity, which is supplied to the electrolyser. The second is the high-
temperature electrolysis of steam. In this system, the concentrator supplies
both heat and AC electricity to convert steam (1273 K) to hydrogen and
oxygen. In this system, an SOFC system would be operated in a reverse
mode to generate hydrogen instead of electricity. This technology is in an
early stage of development.
2.8 There are more than 356 thermo-chemical cycles for the production of
hydrogen by splitting water (without using electricity) though only around a
dozen of these cycles such as the iron oxide cycle, cerium(IV) oxide-
cerium(III) oxide cycle, zinc-zinc-oxide cycle, sulphur-iodine cycle, copper-
chlorine cycle and hybrid sulphur cycle are under research and in testing
phase. These processes can be more efficient than high-temperature
electrolysis, typical in the range from 35 - 49% (lower heating value)
efficiency. Thermo-chemical production of hydrogen using chemical energy
from coal or natural gas is generally not considered, because the direct
chemical path is more efficient. None of the thermo-chemical hydrogen
production processes have been demonstrated at production levels, although
several have been demonstrated in laboratories.
2.9 Biological Hydrogen Production
It is the fermentative conversion of organic substrate to bio-hydrogen
manifested by a diverse group bacteria using multi enzyme systems involving
three steps similar to anaerobic conversion. Two different fermentation routes-
dark fermentation and photo-fermentation routes are available. Dark
fermentation reactions do not require light energy, so they are capable of
constantly producing hydrogen from organic compounds throughout the day
and night. Photo-fermentation differs from dark fermentation because it only
proceeds in the presence of light. Biological hydrogen can be produced in an
algae bioreactor. In the late 1990s it was discovered that if the algae is
deprived of sulphur, it will switch from the production of oxygen, i.e. normal
photosynthesis, to the production of hydrogen.
Biological hydrogen can also be produced in bioreactors that use feed-
stocks other than algae, the most common feedstock being waste streams.
The process involves bacteria feeding on hydrocarbons and excreting
33
hydrogen and CO2. The CO2 can be sequestered successfully by several
methods, leaving hydrogen gas. A prototype hydrogen bioreactor using waste
as a feedstock is in operation at Welch's grape juice factory in North East,
Pennsylvania.
2.10 Bio-catalyzed Electrolysis
The electrolysis using microbes provides another possibility of
producing hydrogen besides regular electrolysis of water, with bio-catalyzed
electrolysis, hydrogen is generated after running through the microbial fuel
cell and a variety of aquatic plants can be used. These include reed sweet-
grass, cord-grass, rice, tomatoes, lupines, algae.
37
3.1 Hydrogen Production from Carbonaceous Sources
3.1.1 Introduction:
Hydrogen has been projected as one of the few long-term sustainable
clean energy carriers, emitting only water vapour as a by-product during the
combustion or oxidation process. Approximately 95% of the hydrogen
produced presently comes from carbonaceous raw materials derived primarily
from a fossilized carbonaceous feed-stock. Only a fraction of this hydrogen is
currently used for energy purposes; the bulk serves as a chemical feedstock
for fertilizer, petrochemical, food, electronics and metallurgical processing
industries. Hydrogen share in the energy market is increasing with the
implementation of fuel cell systems and the growing demand for zero-
emission fuels. Hydrogen production will need to keep pace with this growing
market.
The use of hydrogen for petrochemicals, fertilizers and as clean and
renewable energy carrier will increase substantially in the coming years as
even more stringent environmental legislations are enforced. Low sulfur
gasoline and diesel fuels will become mandatory and harmful emissions will
have to be reduced drastically. Hydrogen will be required by refiners and
specialty chemical manufacturers to meet the global need for cleaner
products. The growing fuel cell market will be dependent on hydrogen as a
primary fuel source. The Hydrogen Posture Plan, published by Energy
Efficiency and Renewable Energy (EERE), USA in February 2004, envisaged
a complete transition to a hydrogen economy by 2030–2040.
However, hydrogen is not readily available in sufficient quantities and
the production cost is still high for transportation purpose. The technical
challenges to achieve a stable hydrogen economy include improving process
efficiencies, lowering the cost of production and harnessing renewable
sources for hydrogen production.
3.1.2 International Status & Commercialisation
Conventional technologies for hydrogen production are:
a) Steam Methane Reforming
b) Partial Oxidation
c) Auto-Thermal Reforming
d) Methanol Reforming
e) Ammonia Cracking
f) Thermo-catalytic Cracking of Methane
g) Novel Reformer Technologies
38
A. Steam Methane Reforming
1. Process Description
Catalytic steam reforming of methane is a well-known, commercially
available process for hydrogen production. Hydrogen production is
accomplished in several steps: steam reforming, water gas shift reaction, and
hydrogen purification.
CH4 + H2O ↔ CO + 3 H2 ∆H= +206.16 kJ/mol CH4
The steam reforming reaction is endothermic and requires external
heat input. Economics favors reactor operation at pressures of 3 to 25
atmospheres and temperatures of 700 to 850°C. The external heat needed to
drive the reaction is often provided by the combustion of a fraction of the
incoming natural gas feedstock (up to 25%) or from burning waste gases,
such as purge gas from the hydrogen purification system. Heat transfer to the
reactants is accomplished indirectly through a heat exchanger. Methane and
steam react in catalyst filled tubes. Typically, the mass ratio of steam to
carbon is about 3 or more to avoid "coking" or carbon build-up on the
catalysts.
After reforming, the resulting syngas is sent to one or more shift
reactors, where the hydrogen output is increased via the water-gas shift
reaction which "converts" CO to H2.
CO + H2O ↔ CO2 + H2 ∆H = - 41.15 kJ/mol CO
This reaction is favored at temperatures of less than about 600°C, and
can take place at as low as 200°C, with sufficiently active catalysts. The gas
exiting the shift reactor contains mostly H2 (70-80%) plus CO2, CH4, H2O and
small quantities of CO. For hydrogen production, the shift reaction is often
accomplished in two stages. A high temperature shift reactor operating at
about 350-475°C accomplishes much of the conversion, followed by a lower
temperature (200-250°C) shift reactor, which brings the CO concentration
down to a few percent by volume or less. Hydrogen is then purified. The
degree of purification depends on the application. For industrial hydrogen,
pressure swing absorption (PSA) systems or palladium membranes are used
to produce hydrogen at up to 99.999% purity.
39
2. Status of Various Types of Steam Methane Reformers
a) Conventional Steam Methane Reformers
Steam methane reformers have been built over a wide range of sizes.
For large-scale chemical processes such as oil refining, steam reformers
produce 25 to 100 million standard cubic feet of hydrogen per day (1 scf =
0.02832 m3 or 28.32 L). These systems consist of long (12 meter) catalyst
filled tubes, and operate at temperatures of 850oC and pressures of 15-25
atm, which necessitates the use of expensive alloy steels. Capital costs for a
20 million scf H2/day steam reformer plant (including the reformer, shift reactor
and PSA) are about $200/kW H2 output; for a 200 million scf/day plant capital
costs are estimated to be about $80/kW H2.Refinery-type (high pressure, high
temperature) long tube reformers can be scaled down to as small as 0.1-1.0
million scf/day (the scale needed for producing hydrogen at refueling
stations), but scale economies in the capital cost are significant. The capital
cost is about $750/kW H2 at 1 million scf/day and $4000/kW H2 at 0.1 million
scf/day. Small-scale conventional (long tube, high temperature) steam
methane reformers are commercially available from a number of companies,
which normally produce large steam methane reformers for chemical and oil
industries. The main design constraints for these systems are high
throughput, high reliability and high purity (depending on the application).
The disadvantages of conventional long tube steam reformers for
hydrogen refueling station applications are their large size (12-meter long
catalyst-filled tubes are commonly used), and high cost (which is due to costly
materials requirements for high temperature, high pressure operation, and to
engineering/installation costs for these one of kind units). For these reasons, it
is generally believed in the hydrogen and fuel cell R&D communities that a
more compact, lower cost reformer will be needed for stand-alone hydrogen
production at refueling stations.
b) Compact “Fuel Cell Type” Steam Methane Reformers with
Concentric Annular Catalyst Beds
At small sizes, a more cost effective approach is to use a lower
pressure and temperature reformer, with lower cost materials. Steam
methane reformers in the range of 2000 to 120,000 scf H2/day have been
developed for use with fuel cells, and have recently been adapted for stand-
alone hydrogen production. In these systems, the heat transfer path is
properly engineered to make the device more compact, and the reformer
operates at a lower pressure and temperature (3 atm, 700°C), which relaxes
materials requirements. Estimates of mass produced costs for small .fuel cell
type. steam methane reformers indicates that the capital cost for hydrogen
40
production plants in the 0.1 to 1.0 million scf/day range would be $150-
$180/kW H2 assuming that 1000 units were produced.
The capital costs per unit of hydrogen production ($/kW H2) are similar
for fuel cell type small reformers and conventional, one-of-a-kind large
reformers, assuming that many small units are built. Energy conversion
efficiencies of 70%-80% are possible for these units.
c) Plate-type Steam Methane Reformers
Another innovation in the design of steam methane reformers for fuel
cell systems is the plate-type reformer. Plate-type reformers are more
compact than conventional reformers with long, catalyst-filled tubes or
annular-type reformers with catalyst beds. The reformer plates are arranged
in a stack. One side of each plate is coated with a steam reforming catalyst
and supplied with reactants (methane and steam). On the other side of the
plate, anode exhaust gas from the fuel cell undergoes catalytic combustion,
providing heat to drive the endothermic steam reforming reaction. The
potential advantages of a plate reformer are more compact, standardized
design (and lower cost), better heat transfer (and therefore better conversion
efficiency), and faster start-up (because each plate has a lower thermal inertia
than a packed catalyst bed).
The various reactors in the steam methane reformer system (e.g.
desulfurizer, steam reformer, water gas shift reactor, and CO clean-up stage)
are made up of plates of a standard size, greatly reducing the capital cost.
Heat transfer and heat integration between reactors is facilitated.
Plate-type steam methane reformers have not yet been
commercialised for fuel cell systems, but may allow for future capital cost
reduction by simplifying system design.
d) Membrane Reactors for Steam Reforming
Another promising technology is the .membrane reactor, where the
steam reforming, water gas shift and hydrogen purification steps all take place
in a single reactor. Methane and steam are fed into a catalyst-filled reactor
under pressure. On one side of the reactor is a high selectivity palladium
membrane that is selectively permeable to hydrogen. As the steam reforming
reaction proceeds, the hydrogen is driven across the membrane by the
pressure difference. Depending on the temperature, pressure and the reactor
length, methane can be completely converted, and very pure hydrogen is
produced, which is removed as the reaction proceeds. This allows operation
at lower temperature, and use of lower cost materials. A potential advantage
41
of this system is simplification of the process design and capital cost reduction
due to the need of fewer process vessels.
There is huge spurt in industrial R&D activity on membrane
technologies for syngas and hydrogen production. Interest by major energy
companies in applying membrane technology to large-scale syngas and
hydrogen production may have significant “spin-offs” for small-scale hydrogen
production as well. Recently patents have been issued on membrane reactor
reforming to a number of companies involved in fuel processor design for fuel
cells and on related ion transport membrane technology to oil companies,
Exxon, BP Amoco, Indiana, Standard Oil, USA and other industrial gas
companies like Air Products and Praxair. Recently Praxair and Argonne
National Laboratory launched a programme to develop a compact, low-cost
hydrogen generator based on ceramic membrane technologies. Steam,
natural gas and oxygen are combined in a catalyzed auto-thermal reforming
reaction. Oxygen is derived from air, using an oxygen transport ceramic
membrane (OTM) that operates at about 800-1000oC. High purity hydrogen is
removed using a high selective hydrogen transport membrane, also operating
at 800-1000oC. The OTM has been developed by Praxair and others in the
Oxygen Transport Membrane Syngas Alliance (BP, London, Amoco,Indiana
Statoil, Norway, Sasol, Johannesburg), South Africa, since 1997, and is now
undergoing Phase II pilot demonstration. The hydrogen transport membrane
is being developed at Argonne National Laboratory, and is in an early stage of
development.
In Japan, the Tokyo Gas company has built and tested a small
membrane reactor for production of pure hydrogen from natural gas at a rate
of 15 Nm3/h (about 12,000 scf/d), as well as steam reforming and partial
oxidation systems. Aspen Systems has demonstrated a membrane reactor for
steam reforming methane, ethanol and gasoline.
B. Partial Oxidation
1. Process Description
Another commercially available method for deriving hydrogen from
hydrocarbons is partial oxidation (POX). Here, methane (or some other
hydrocarbon feedstock such as oil) is oxidized to produce carbon monoxide
and hydrogen according to
CH4 + 1/2 O2→ CO + 2 H2 ∆H = -36 MJ/kmol CH4
The reaction is exothermic and no indirect heat exchanger is needed.
Catalysts are not required because of the high temperature. However, the
42
hydrogen yield per mole of methane input (and the system efficiency) can be
significantly enhanced by use of catalysts. A hydrogen plant based on partial
oxidation includes a partial oxidation reactor, followed by a shift reactor and
hydrogen purification equipment. Large-scale partial oxidation systems have
been used commercially to produce hydrogen from hydrocarbons such as
residual oil, for applications in refineries, etc. Large systems generally
incorporate an oxygen plant, because operation with pure oxygen, rather than
air, reduces the size and cost of the reactors.
Small-scale partial oxidation systems have recently become
commercially available, but intensive R&D activities are still underway. Small-
scale partial oxidation systems have a fast response time, making them
attractive for following rapidly varying loads, and can handle a variety of fuels,
including methane, ethanol, methanol, and gasoline.
The POX reactor is more compact than a steam reformer, in which heat
must be added indirectly via a heat exchanger. The efficiency of the partial
oxidation unit is relatively high (70-80%). However, partial oxidation systems
are typically less energy efficient than steam reforming because of the higher
temperatures involved (which exacerbates heat losses) and the problem of
heat recovery. (In a steam methane reforming plant, heat can be recovered
from the flue gas to raise steam for the reaction, and the PSA purge gas can
be used as a reformer burner fuel to help provide heat for the endothermic
steam reforming reaction. In a POX reactor, in which the reaction is
exothermic, the energy in the PSA purge gas cannot be fully recovered).
Because they are more compact, and do not require indirect heat
exchange (as in steam reforming), it has been suggested that partial oxidation
systems could cost less than steam reformers. Although the partial oxidation
reactor is likely to be less expensive than a steam reformer vessel, the
downstream shift and purification stages are likely to be more expensive.
Developing low cost purification technologies is the key, if POX systems are to
be used for stationary hydrogen production. Another approach is using pure
oxygen feed to the POX, which incurs high capital costs for small-scale
oxygen production, but eliminates the need to deal with nitrogen downstream.
Oxygen enrichment of incoming air is another way of reducing, but not
eliminating, the amount of nitrogen. Innovative membrane technologies such
as the Ion Transport Membrane (ITM) may allow lower cost oxygen for POX
reactors. This is being investigated by Air Products in its research related to
ITMs, and by Praxair and partners in its oxygen transport membrane
programme.
43
2. Status of Partial Oxidation Systems
A number of companies are involved in developing small-scale POx
systems. Small POx systems have been developed, for use with fuel cell
systems, by Arthur D. Little and its spin-off companies Epyx and Nuvera. Epyx
is supplying the onboard gasoline reformer for the USDOE’s gasoline fuel cell
vehicle project. Epyx recently formed a joint company with DeNora called
Nuvera, to commercialise POX reformer/PEM fuel cell systems. Nuvera has
reportedly shipped gasoline reformers to automotive companies for testing.
Hydrogen Burner Technology (HBT), Inc., California, USA has
developed a range of hydrogen production systems based on POx. This
includes a reformer that produces very pure H2 for cogeneration in buildings.
HBT, with funding from the California Air Resources Board, is installing a
natural gas reformer filling station for Sunline Transit at Thousand Palms, CA,
to supply hydrogen to fuel cell buses and Hythane® buses. HBT has a joint
venture with Gaz de France to distribute HBT’s products in Europe. Phoenix
Gas Systems (a HBT sub group) develops systems for industrial hydrogen
gas generation.
Argonne National Laboratory, Lemont, Illinois, USA has developed a
POx reformer suitable for use in vehicles. The USDOE is supporting work on
POx systems for onboard fuel processors for fuel cell vehicles through the
Office of Transportation Technologies Fuel Cell Program. Several companies
are involved in developing multi-fuel fuel processors for 50 kW fuel cell vehicle
power plants. These include:
As part of the Arthur D. Little/ Epyx/ Nuvera partnership, a gasoline fuel
processor built by Epyx was demonstrated with a PEM fuel cell. Plug
Power, Latham, New York is building an integrated 50 kW
gasoline/PEMFC system, based on the Epyx reformer.
McDermott Technology Inc., Alliance, Ohio, USA and Catalytica
Energy Systems Inc., Arizona are developing a multi-fuel fuel
processor for a 50 kW fuel cell.
Hydrogen Burner Technologies, Inc. is developing a multi-fuel
processor for a 50 kW fuel cell.
In addition, a number of automotive companies are in joint ventures to
develop gasoline fuel processors based on POX technology. These include:
General Motors. USA has joined with Exxon Mobil, USA to develop an
onboard gasoline fuel processor.
44
International Fuel Cells, South Windsor, USA has partnered with Shell
Hydrogen, Torrance, USA to develop and market a variety of fuel
processors.
Projects to use POx systems in stationary fuel cells include:
Tokyo Gas Company, Japan, has demonstrated a POx system for 1
kW fuel cell cogeneration system.
McDermott Technology, Inc. (MTI), USA and Catalytica Energy
Systems Inc., Tempe, Arizona, United States are working together to
develop compact fuel processors for use with PEMFCs and solid oxide
fuel cells (SOFCs). This system is designed to reform gasoline and
Naval Distillate for PEMFCs.
C. Autothermal Reforming
1. Process Description
Autothermal reformers (ATRs) combine some of the best features of
SMR and POx systems. Several companies are developing small ATRs for
converting liquid hydrocarbon fuels to hydrogen for use in fuel cell systems. In
autothermal reforming, a hydrocarbon feed (methane or a liquid fuel) is
reacted with both steam and air to produce a hydrogen-rich gas. Both the
SMR and POx reactions take place. For example, with methane
CH4 + H2O ↔ CO + 3 H2 ∆H = +206.16 kJ/mol CH4
CH4 + ½ O2→ CO + 2 H2 ∆H = -36 MJ/kmol CH4
With the right mixture of input fuel, air and steam, the POx reaction
supplies all the heat needed to drive the catalytic steam reforming reaction.
Unlike the SMR, the ATR requires no external heat source and no indirect
heat exchangers. This makes ATRs simpler and more compact than SMRs,
and it is likely that ATRs will have a lower capital cost. In an ATR all the heat
generated by the POx reaction is fully utilized to drive the steam reforming
reaction. Thus, ATRs typically offer higher system efficiency than POx
systems, where excess heat is not easily recovered. As with a SMR or POx
system, water gas shift reactors and a hydrogen purification stage are
needed.
2. Status of Autothermal Reformers
ATRs are being developed by a number of groups, mostly for fuel
processors of gasoline, diesel and logistics fuels and for natural gas fueled
45
PEMFC cogeneration systems. These include:
Argonne National Laboratory is testing ATR systems and catalysts
International Fuel Cells (IFC), South Windsor, USA designed an
ATR that runs on logistics fuels. BWX Technologies, Inc.,
Lynchburg, Virginia, and McDermott Technology, Inc. Using the IFC
ATR, a system was designed to reform Naval distillate for shipboard
fuel cells
Fraunhofer Institute for Solar Energy Systems, Freiburg, Germany
is designing ATRs for LPG and diesel fuel.
Degussa Metals Catalyst, Cardec Ag, Hanau, Germany is
developing catalysts for ATRs used with gasoline
Johnson-Matthey, Hamilton Bermuda developed a .Hot-Spot.
autothermal reformer, capable of reforming methanol and methane
Honeywell and Energy Partners, USA are developing a 50 kW
PEMFC system for buildings cogeneration. Both SMR and ATR are
being tried.
Daimler-Chrysler, USA is developing an ATR for gasoline reforming
McDermott Technology, Inc. (MTI), USA and Catalytica Energy
Systems Inc.,Tempe, Arizona, United States are developing a
small autothermal reformer for use with diesel and logistics fuels
on ships, based on an IFC design. A regenerable desulfurization
stage is important for Navy diesel fuel with 1% sulfur. Partners in
this activity are McDermott Technology, Inc. and Catalytica
Advanced Technologies, California, USA Ballard, Burnaby,
Canada,BWX Technologies, Lynchburg, Virginia, USA and Gibbs
& Cox, Arlington, Virginia, USA
The Idaho National Energy. USA and Environment Laboratory
(INEEL), USA with MTI and Pacific Gas and Electric, USA have
recently begun work on developing a 10 kW ATR system for
hydrogen refueling station applications.
Analytic Power, Canada has assessed multi-fuel reformer
technology, including ATR.
IdaTech, Bend, Oregon, United States has developed a multi-fuel
reformer, which produces very pure hydrogen from methane. It is
likely that the reformer is either a POX or ATR type.
Recently, Hydrogen Burner Technologies, Inc., Long Beach,
California, US began development of an autothermal reforming
system for use with fuel cells and for hydrogen production.
46
D. Methanol Steam Reforming
1. Process Description
Methanol is a liquid fuel that can be more easily stored and transported
than hydrogen. Because it can be readily steam reformed at moderate
temperatures (250-350oC), methanol has been proposed as a fuel for fuel cell
vehicles. Experimental fuel cell vehicles with onboard methanol reformers
have been demonstrated by Daimler-Chrysler, USA and Toyota and Nissan,
Japan. Although methanol steam reforming technologies are being developed
for fuel processors onboard fuel cell vehicles, it has also been suggested that
hydrogen might be produced by steam reforming of methanol at refueling
stations (Ledjeff-Hey et al. 1998).
The reactions for production of hydrogen via methanol steam reforming
are as follows:
CH3OH ↔ CO + 2 H2, ∆H = 90.1 kJ/mol; Methanol reforming
CO + H2O ↔ CO2 + H2 ∆H=-41.2 kJ/mol; Water gas shift reaction
or combining these:
CH3OH + H2O ↔ CO2 + 3H2
The reaction takes place in the presence of copper/zinc catalysts in the
temperature range 200- 350°C. Overall the reaction is endothermic, requiring
the application of heat, through an indirect heat exchanger, to a catalyst filled
tube or catalyst plate. Good thermodynamic conversion has been reported for
steam-to-carbon ratios of 1.5 and temperatures of 250-350°C. Various types
of methanol steam reformers have been designed. Earlier designs use
catalyst filled tubes that are indirectly heated via combustion of some of the
incoming methanol fuel. More recently, there has been an effort to develop
plate type reformers for methanol reforming. These have a number of
potential advantages including compactness, better heat transfer, faster start-
up and potentially lower cost. Membrane reactors have also been built for
steam reforming methanol.
For refueling station applications, a hydrogen purification stage, either
pressure swing adsorption unit or a membrane separation type, unit may be
required. The cost of the hydrogen production system might be lower for a
methanol steam reformer because it would operate at much lower
temperatures than a steam methane reformer. The cost of hydrogen produced
from methanol would be higher than hydrogen from small-scale steam
methane reforming, because methanol is a more expensive feedstock than
47
natural gas.
2. Status of Methanol Steam Reformers
Researchers at Los Alamos National Laboratory, USA have conducted
research on methanol steam reforming for PEM fuel cells. Researchers
at Argonne National Laboratory, USA have also simulated and built
methanol steam reformers.
Several automakers demonstrating fuel cell vehicles have developed
onboard steam reformers for methanol. These include Excellis Fuel
Cell Engines (DaimlerChrysler) of USA, and Toyota and Nissan of
Japan.
The European Commission funded two projects to develop onboard
fuel processors for fuel cell vehicles as part of the JOULE II project.
The MERCATOX project had the goal of producing a prototype
integrated methanol reformer and selective oxidation system.
Wellman CJB Ltd., a British company that has produced units for
steam reforming of alcohols, hydrocarbons, ethers and military fuels,
coordinated the MERCATOX project. The reformer consists of a series of
catalytic plates, with combustion of anode off-gas on one side and reforming
on the other side. Loughborough University designed the gas clean-up
system. Wellmann built and tested a plate type steam methanol reformer and
integrated the system, Rover Cars Company addressed manufacturing and
vehicle design issues, and Instituto Superior Technico undertook modeling
work
Northwest Power Systems (now called IdaTech), Thief River Falls,
Minnesota, United States has developed a multi-fuel processor. They
have demonstrated pure hydrogen production via steam reforming of
methanol, using a palladium membrane for the final purification step
Researchers at InnovaTek, Inc., Richland, Washington, USA have
demonstrated microreactor technology to create a portable hydrogen
source for fuel cells by reforming methanol
Researchers at Mitsubishi Electric Corporation, Japan are developing a
compact, plate-type steam methanol reformer
Researchers at the Royal Military College, Ontario, Canada, are
studying the effects of catalyst properties on methanol reforming
Researchers at Honeywell, USA are developing a compact plate-type
steam methanol reformer for automotive applications
Researchers at NTT Telecommunications Laboratory, and Tokyo
University are developing a compact plate-type steam methanol
reformer for automotive applications
48
Researchers at Gerhard-Mercator-Universitat, FRG, are developing
compact membrane reactors for methanol steam reforming
E. Ammonia Cracking
Ammonia is widely distributed to consumers today, is low cost and is
relatively easy to transport and store, compared to hydrogen. These attributes
make it a potential candidate for use as a hydrogen carrier for fuel cell
applications.
Ammonia can be dissociated (or cracked) into nitrogen and hydrogen
via the reaction:
2 NH3 -> N2 + 3 H2
The reaction is endothermic, and ammonia cracking takes place in indirectly
heated catalyst filled tubes. The dissociation rate depends on the
temperature, pressure and catalyst type. The reaction rate is increased by
operating at temperatures of 700oC or above, although dissociation can occur
at temperatures as low as 350oC. The main impurities are traces of un-
reacted ammonia and nitrogen oxides. The concentration of un-reacted
ammonia must be reduced to the ppm level for use in PEM fuel cells, although
alkaline fuel cells are not as sensitive to this. For PEMFC applications, where
low levels of ammonia impurity are required, a recent study recommends
reaction temperatures of 900oC .The overall efficiency of fuel processor
systems based on ammonia cracking has been reported to be up to 85%.
Maximum values of about 60% were reported in another recent study, by
Analytic Power, for small ammonia crackers for PEM fuel cell applications,
where up to 40% of the product hydrogen was combusted to supply heat to
drive the dissociation reaction and to compensate for heat losses.
A potential advantage of ammonia cracking for hydrogen generation in
a fuel cell system is simplicity of reactor. Unlike a steam reformer system,
water is not required as a co-feed with the fuel, and no water gas shift
reactors are needed. When an ammonia cracker is closely coupled to a fuel
cell, no final hydrogen purification stage is needed. Because nitrogen is inert
and has no effect in the fuel cell, it is simply passes through as a diluent. For
pure hydrogen production based on ammonia cracking, however, a costly
separation of H2 and N2 would be required, for example by using a PSA unit
or a hydrogen selective membrane. The cost of pure hydrogen production
through ammonia cracking has not yet been estimated.
49
F. Thermo-catalytic Cracking of Methane
In this approach, methane is broken down into carbon and hydrogen in
the presence of a catalyst at high temperature (850-1200oC), according to the
reaction
CH4 → C + 2 H2 ∆H = 17.8 kcal/mole CH4
This reaction is endothermic, requiring energy input of about 10% of the
natural gas feedstock. Researchers at the Florida Solar Energy Center, USA
have studied thermocatalytic methane cracking. This technology is still far
from commercial application for hydrogen production. The primary issues are
low efficiency of conversion and coking (carbon fouling of the catalyst).
Catalytic cracking of other hydrocarbons has been investigated by
researchers at Gerhard- Mercator-Universitat at Duisburg, Germany. Frequent
regeneration of the catalyst is required to remove accumulated carbon, but
relatively low capital costs are projected because of the system’s simplicity.
G. Novel Reformer Technologies
1. Sorbent Enhanced Reforming
Recently several authors have investigated the possibility of sorbent
enhanced steam methane reforming. Here, an absorbent (such as calcium
oxide) is mixed with the steam reforming catalyst, removing the CO and CO2
as the steam reforming reaction progresses. The resulting syngas has a
substantially higher fraction of hydrogen than that produced in a catalytic
steam-reforming reactor. A syngas composition was recently reported of 90%
H2, 10%CH4, 0.5% CO2 and <50 ppm CO. This reduces the need for
downstream processing and purification, which can be expensive in a small-
scale steam reformer. Moreover, when CO2 is removed by the sorbent, the
reaction can take place at lower temperature (400-500oC vs. 800-1000oC) and
pressure, reducing heat losses and material costs. Sorbent-enhanced
systems are still at the demonstration stage, and show promise because of
their low cost. Issues requiring further research include catalyst and sorbent
lifetime and system design.
2. Ion Transport Membrane (ITM) Reforming
Air Products, in collaboration with the USDOE and other members of
the ITM syngas team (Cerametec, Chevron, Eltron Research, McDermott
Technology, Norsk Hydro, Pacific Northwest Laboratory, Pennsylvania State
University, University of Alaska, and University of Pennsylvania, all from
USA), are developing ceramic membrane technology for generation of H2 and
50
syngas. The membranes are non-porous, multi-component metallic oxides
that operate at high temperature (>700oC) and have high oxygen flux and
selectivity. These are known as ion transport membranes (ITM). Conceptual
designs were carried out for a hydrogen-refueling station dispensing 0.5
million scf/day of 5000 psi hydrogen, following work by Directed Technologies,
Inc. Initial estimates show the potential for a significant reduction in the cost of
high pressure H2 produced via this route at the 0.1 to 1.0 million scf/day size.
For example, compared to trucked-in liquid hydrogen, the ITM route offers a
27% cost savings. Oxygen can be separated from air fed to one side of the
membrane at ambient pressure or moderate pressure (1-5 psig) and reacted
on the other surface with methane and steam at higher pressure (100-500
psig) to form a mixture of H2 and CO. This can then be processed to make
hydrogen or liquid fuels. Various configurations for the ITM reactor were
examined, and a flat-plate system was chosen because it reduced the number
of ceramic-metal seals needed. An independent effort to develop oxygen
transport membranes is ongoing at Praxair in conjunction with the Oxygen
Transport Membrane Syngas Alliance.
3. Plasma Reformers
Thermal plasma technology can be used in the production of hydrogen
and hydrogen-rich gases from methane and a variety of liquid fuels. Thermal
plasma is characterized by temperatures of the order of 3000-10,000oC, and
can be used to accelerate the kinetics reforming reactions even without a
catalyst. The plasma is created by an electric arc. Reactant mixtures (for
example, methane plus steam or diesel fuel plus air and water) are introduced
into the reactor and H2 plus other hydrocarbon products are formed.
Researchers at MIT, USA (Bromberg et al. 1999) have developed plasma-
reforming systems. The plasma is created by an electric arc in a plasmatron.
One set of experiments involved partial oxidation of diesel fuel. Steam
reforming of methane was also investigated. The best steam reforming results
to date have shown 95% conversion of methane and specific energy use (for
electricity for the plasmatron) of 14 MJ/kg H2 (an amount equal to about 10%
of the higher heating value of hydrogen). It is projected that the power
required for the plasmatron can be reduced by about half. With the National
Renewable Energy Laboratory (NREL) and BOC Gases, MIT researchers are
evaluating the potential of this technology for small-scale hydrogen
production. Researchers at Idaho National Energy and Environment
Laboratory (INEEL), USA and DCH are also working on plasma reforming
(DOE Hydrogen R&D Program Annual Operating Plan, March 2000).
4. Micro-channel Reformer
Researchers at Pacific Northwest National Laboratory, USA have
51
developed a novel gasoline steam reformer with micro-channels. The aim of
this work is to reduce the size of automotive reformers.
Over the past ten years, the rapidly growing interest in fuel cell and
hydrogen technologies has led to a variety of efforts to develop low cost
small-scale fuel processors and hydrogen production systems. The trend has
been to develop more compact, simpler and, therefore, lower cost reformers.
From the conventional long tube refinery-type steam methane reformer, fuel
cell developers moved toward more compact heat exchange-type steam
reformers (which are now commercialised as fuel cell components and for
stand-alone hydrogen production). Plate type reformers are now undergoing
development and testing for fuel cell applications and may be the next step in
compactness and simpler design. In plate reformers, each plate has a double
function (on one side, the reforming reaction take place, on the other, catalytic
heating drives the reaction). POx systems and ATRs offer simpler first stages
than steam reformers, but involve more complex purification systems.
Advanced purification systems are being devised for these reformers. Sorbent
enhanced reforming is another approach that combines several steps in one
reactor, with the potential of capital cost reductions. An area of intense
interest in the fuel cell and hydrogen R&D communities is development of
membrane reactors for reforming. Membrane reactors offer further
simplification, because the reforming, water gas shift and purification step
take place in a single reactor. Very pure hydrogen is removed via hydrogen-
selective permeable membranes. Membrane reactor systems are being tested
at small scale.
In parallel with fuel cell developments, there has been a growing
interest in innovative technologies for syngas production among large
chemical and energy producing companies. For example, ion transport and
oxygen transport membranes are under development for syngas applications.
These are now being applied to hydrogen production as well. Application of
membrane technology to syngas and hydrogen systems is an active area of
research in the fuel cell R&D community and among large-scale producers of
syngas such as oil companies. In addition, oil companies such as BP Amoco,
U. K.; Shell, Houston, USA and Exxon/Mobil, Houston, Texas are involved in
joint ventures to develop fuel processors and hydrogen infrastructure
demonstrations, such as hydrogen refueling stations based on methane
reformers. The oil companies are positioning themselves to become suppliers
of hydrogen transportation fuel in the future.
3.1.3 National Status and Commercialisation Efforts by industry
The focus of RD&D in India has been on production of hydrogen from
renewable sources of energy.
52
(a) Status of Hydrogen Production Technologies in India
The Indian Institute of Chemical Technology (IICT), Hyderabad
designed and developed a methanol reformer to produce around 10,000
litres/hour hydrogen for coupling with 10 kW fuel cell. It was operated for 1000
hours and data was collected. Based on this data a scaled up methanol
reformer to produce around 50,000 litres/hour hydrogen was designed and
developed to demonstrate the technology by coupling with 50 kW fuel cell
system. The reformed gas contained around 75% hydrogen with pre-mixed
methanol and water. The product gas was further processed to lower down
CO2 and CO content to the extent less than 10 ppm, which is desirable for use
in PEMFC system for power generation.
IICT, Hyderabad also developed three catalysts viz, Ni/SiO2 (NS), Ni/
Alumina Sol [Ni/Al2O3] Ni/ Alumina Plural (NAP) [Ni/Al2O3] for reformation of
glycerol at 500-650ºC on bench scale for hydrogen production to generate
data of reaction kinetics to scale-up reformer. Based on this data a skid
mounted reactor was fabricated and installed at the institute. The life of these
catalyst lasted for several hours.
The Centre for Energy Research, SPIC Science Foundation, Chennai
(stopped R&D activities on hydrogen energy and fuel cells) designed,
developed and demonstrated a PEM methanol electrolyser for the production
of hydrogen at the rate of 1 Nm3/hour at an operating temp of 50-60oC. The
energy consumption was around 2.02 kWh/Nm3hydrogen produced. The
hydrogen gas obtained from this electrolyser contains considerable amount of
methanol, which can be removed bypassing it through water scrubber and
chiller. This hydrogen is almost free from CO2 and CO.
Central Institute of Mining and Fuel Research (CIMFR), Dhanbad
developed an ovel process for the production of hydrogen from renewable
and fossil fuel based liquid and gaseous hydrocarbons by non-thermal plasma
reformation technique. A non-thermal plasma reactor of 0.5 litre capacity was
developed for reformation of hydrocarbons to produce about 12 litres/minute
hydrogen enriched gas mixture. Conversion of methane to hydrogen has been
studied in a quartz reactor by non-thermal plasma. Experiments have been
conducted for non-thermal plasma reformation of soybean oil, methanol and
ethanol with both conventional cylindrical fuel reformer as well as vortex type
reformer. Appreciable hydrogen production was also achieved with naphtha.
Bio-diesel will also be tried for hydrogen production through this process.
The Indian Institute of Technology Hyderabad is working for the
transformation of greenhouse gases like methane and CO2 into for
53
syngas/H2bylow temperature plasma catalysis. This will be achieved by
optimizing conditions like reactor design, diluting gas, discharge gap,
residence time of the gas, screening of various catalysts, etc. for a hybrid non-
thermal plasma reactor. Heterogeneous catalysts will be searched /
synthesized to arrive at a robust and cost-effective catalytic non-thermal
plasma reactor for syngas production. Earlier IIT Hyderabad had worked on
developing a process for dissociation of hydrogen sulphide into hydrogen and
sulphur using non-thermal plasma process.
b) Gap Analysis & Way Forward
There are already extensive industry and government programmes
addressing particular technical issues for small-scale reformers, and for
syngas production. We have not attempted to list research priorities for each
type of reformer, or select a particular technical area for basic research.
Instead, we suggest that the National/International agencies develop
collaborative projects aimed at enhancing interactions between researchers
engaged in small-scale hydrogen production (fuel cell and hydrogen
researchers) and those engaged in large energy production (oil and chemical
companies). The purpose of the proposed projects would be to examine the
potential impact of recent technical progress for small- and large-scale
hydrogen energy production.
One project could be to identify areas where ongoing research on
large-scale syngas technologies could lead to development of small-
scale hydrogen production systems for vehicles, and vice versa. To
identify such areas, the MNRE could convene a group of industry and
academic researchers from fuel cell, hydrogen and energy producing
communities to discuss issues for small-scale reformers for hydrogen
production. This group might have particular interest in technologies
that could have applications in small- and large-scale hydrogen
production and could ultimately facilitate capture ofCO2 during
hydrogen fuel production. Membrane technology would appear to be a
good candidate for such an information exchange meeting, but other
areas might be identified. If gaps in technical knowledge were
identified, this could help focus future reformer development efforts.
54
3.2 Hydrogen Production through Biomass Gasification
3.2.1 Biomass is a renewable source of energy and can be considered as a
distributed source for hydrogen production. However, out of all different routes
of hydrogen production from biomass, gasification is likely to be the most
economical and sustainable process. The basic steps for getting pure
hydrogen out of biomass through gasification are similar to those for coal,
methane and naphtha reforming based processes.
3.2.2 International Status
Research & development work in the area of production of hydrogen
using biomass is being carried out at the international level by various
organisations. However, till date no commercial technology is available to
generate hydrogen from biomass. The reported hydrogen production is
mainly through fluidized bed gasification or conversion of pyrolytic oil. The
work done at various institutions/ organisations is summarised below:
The University of British Colombia, Canada, is working on fluidized bed
gasification and sorbent based hydrogen separation unit. The National
Renewable Energy Laboratory (NREL), U.S.A. has demonstrated production
of hydrogen from pyrolysis oil by steam reforming. This pyrolysis oil was
obtained from peanut shells in a fluidized bed by pyrolysis process. Some
studies were done on pyrolysis and gasification of rubber, poplar wood, yellow
pinewood and residual branches of oil palm tree as fuel in a thermally
controlled environment and steam was passed at the desired flow rate over a
fixed mass of biomass for gasification. The gasifier was operated in the
temperature ranges of 600-10000C and 800 - 9000C. Maximum yield of
hydrogen was obtained in the temperature range of 600-10000C. The
hydrogen yield was about 20 g per kg of biomass through pyrolysis and 97 g
per kg of biomass through steam gasification, with over 55% volume fraction
of hydrogen in the syngas. The influence of temperature on various
performance parameters was evaluated and analyzed. There were no
significant changes in syngas and hydrogen yield at various gasification
temperatures but the pyrolysis temperature had a considerable effect on the
overall yield. The syngas yield increased from 353 g per kg of biomass to 828
g per kg of biomass by varying the pyrolysis temperature from 600 to 10000C
with a reduction of over 50% in solid residue at the end of the process. The
reaction rates enhanced significantly with increase in temperature, 35 g of
substrate took 200 min for complete gasification at 6000C compared to 29 min
at 10000C for constant flow of steam at 3.1 g/s. The extremely slow rate of the
char-steam reaction is cited as the reason for the slow rate of gasification at
low temperatures. High temperature and long residence time were identified
55
as important parameters that favor higher H2 yields. Over 30% higher energy
yield was reported from gasification compared to pyrolysis due to significant
contribution of the char-steam reaction.
Gas Technology Institute (GTI), Chicago, has been working on
demonstration project for direct generation of hydrogen in a down draft
gasifier using a membrane reactor. The Energy Research Centre of the
Netherlands (ECN) has developed gasification technology, which has
progressed to a pilot plant scale (800 kWth).Currently ECN, with other partners
is planning to construct a 12 MWth synthetic natural gas (SNG) plant in
Alkmaar, the Netherlands. The gasifier has been designed with a tar
scrubbing unit. Methanation of the product gases is done after removing
sulphur, chloride and CO2. The Technical University of Vienna has developed
a fast internally circulating fluidized-bed technology for steam-blown
gasification of biomass in cooperation with Austrian Energy and Environment.
This technology is being employed in the Gothenburg Biomass Gasification
(GoBiGas), project, which aims at constructing a SNG plant in Gothenburg,
Sweden. At Gussing, Austria, an 8 MW combined heat and power plant is in
operation since 2002. Later on, SNG production was demonstrated in a
methanation unit, which took a 1 MW SNG slipstream from the Güssing plant.
There has been no reported work on fixed bed gasification. The targeted cost
of production of hydrogen was around US$ 2.6/kg.
3.2.3 Biomass Pyrolysis
Pyrolysis is the heating of biomass at a temperature of 600-10000C at
0.1–0.5 MPa in the absence of air to convert biomass into gaseous
compounds, liquid oils, and solid charcoal. Pyrolysis can be further classified
into slow and fast pyrolysis. As slow pyrolysis gives high char yield, it is
generally not considered for hydrogen production. Fast pyrolysis is a process
where biomass feedstock is heated rapidly (at 150-250oC/s) in the absence of
air, to form vapour and subsequently condense it to a dark brown bio-liquid.
The following products are obtained from the fast pyrolysis process:
(i) Gaseous products include H2, CH4, CO, CO2 and other Higher Hydro
Carbons (HHC) depending on the organic nature of the biomass.
(ii) Liquid products include tar and oils that remain in liquid form at room
temperature like acetone, acetic acid, etc.
(iii) Solid products are mainly composed of char and almost pure carbon
plus other inert materials.
Although most pyrolysis processes are designed for biofuels
production, hydrogen can be produced directly through fast or flash pyrolysis,
56
if high temperature and sufficient volatile phase residence time are allowed as
follows:
Biomass +heat →H2+ CO +CH4 + HHC + C (char) - - (i)
CO, methane and other hydrocarbons are reformed catalytically in
subsequent stages to get more hydrogen. Besides the gaseous products, the
oily products can also be processed for hydrogen production. The pyrolysis oil
can be separated into two fractions based on water solubility. The water-
soluble fraction is used for hydrogen production while the water-insoluble
fraction for adhesive formulation.
Studies have shown that when Ni-based catalyst is used, the maximum
yield of hydrogen can reach 90%. Bio-oil needs to be steam reformed at 750-
850 0C in presence of nickel based catalyst followed by shift reaction. With
additional steam reforming and water–gas shift reaction, the hydrogen yield
can be increased significantly. Temperature, heating rate, residence time and
type of catalyst used are important pyrolysis process control parameters. In
favor of gaseous products especially in hydrogen production, high
temperature, high heating rate and long volatile phase residence time are
required.
3.2.4 Biomass Gasification
Biomass gasification is sub-stoichiometric combustion process, in
which pyrolysis, oxidation and reduction take place. Pyrolysis products
(volatile matter) further reacts with char and are reduced to H2, CO, CO2, CH4
and HHC.
Biomass + heat + O2 → H2 +CO + CO2 + CH4 + HHC + char - (ii)
Unlike pyrolysis, gasification of solid biomass is carried out in the
presence of oxidiser. Besides, gasification aims to produce gaseous products,
while pyrolysis aims to produce bio-oils and charcoal. One of the major issues
in biomass gasification is to deal with the tar formation that occurs during the
process. The unwanted tar may cause the formation of tar aerosols through
polymerization to a more complex structure, which are not favorable for
hydrogen production through steam reforming. This tar formation may be
minimized by: i) designing gasifier properly, ii) with controlled operation (in
terms of temperature and residence time) of gasifier and iii) with
additives/catalysts.
57
Tar may be thermally cracked at temperature above 10000C. The two-
stage gasification and secondary air injection in the gasifier may also reduce
tar formation.
The use of some additives (dolomite, olivine and char) inside the
gasifier also helps in tar reduction. When dolomite is used, 100% elimination
of tar can be achieved. Catalysts not only reduce the tar content, but also
improve the gas product quality and conversion efficiency. Dolomite, Ni-based
catalysts and alkaline metal oxides are widely used as gasification catalysts.
H2 content in biomass is only around 6.5% (by wt.). But using steam as
the gasifying agent and air/O2 as the oxidizer, enhances the H2 output
considerably. One of the major advantages of the gasification is that the
process is carbon neutral and it has flexibility in using various types of
biomass including agricultural and municipal solid waste.
3.2.5 Thermo-chemical Conversion of Biomass: As a process for
hydrogen generation this route had never been a prime area of research, but
major emphasis was towards standardizing the gasification system for power
generation using reciprocating engines and for thermal applications. Biomass
gasification has been identified as a possible process for producing renewable
hydrogen. Most of the research has been stimulated by the techno-
economics, based on gasifier performance data acquired during proof of
concept testing.
In recent years, many researchers have explored the gasification of
biomass for hydrogen production using different reactor configurations. In a
fluidized bed reactor steam was introduced with oxygen and nitrogen under
temperature controlled conditions. The reactor was externally heated to
control the reactor temperature and the reactant flow rates were varied to
determine the effect of the equivalence ratio and the steam to biomass ratio
on the gas quality. H2 yield showed pronounced improvement with increasing
reactor temperature. Increasing the temperature from 800 to 9500C (at SBR =
1.8 and ER = 0.18) doubled the yield of H2 from 28 to 61 g per kg of biomass.
The effect of increased steam to biomass ratio (SBR) and equivalence ratio
(ER) on the hydrogen yield suggests that increasing the SBR (at an ER = 0)
from 1.1 to 4.7 increased the hydrogen yield from 46 to 83 g per kg of
biomass, whereas reducing the ER from 0.37 to 0 (at SBR = 1.7) enhanced
the H2 yield from 23 to 60 g per kg of biomass. The maximum H2 volume
fraction in syngas is reported as 57% at SBR of 4.7 and ER of 0, while
maintaining the bed temperature at 8000C The reported tar levels are in the
range of 6 g per kg of dry fuel, amounting to about 2500 ppm of tar and can
have serious implications on the downstream elements for hydrogen
separation.
58
Oxygen-steam gasification has been reported using pinewood
(CH1.6O0.6) with 8% moisture as fuel in a fixed bed downdraft gasifier. The 1.3
m high and 35 cm diameter downdraft gasifier was preheated up to 9000C by
igniting the feedstock and circulating the heat by a fan. Later, biomass was
placed over a bed of charcoal and oxygen was injected from multiple points.
Saturated steam at near ambient pressure was used. The oxy-steam
gasification was performed with ER varying between 0.22 and 0.26 and SBR
varying between 0.4 and 0.8 (molar basis). The maximum hydrogen yield
reported is 49 g per kg of dry biomass at ER of 0.25 and SBR of 0.8.A high tar
yield in the range of 3 to 20 g per kg of biomass was reported.
The effect of heating rate, temperature and SBR on H2 yield, tar
reduction and char residue was also studied in a co-current flow using a 1.8 m
long downdraft reactor of 20 mm diameter with legume straw and pine
sawdust as feed-stock. Steam was injected at 3000C, keeping the reactor at
the desired temperature using electrical heating coils. SBR (on mass basis)
was varied from 0 to 1 while working in a temperature range of 700 - 8500C.
Steam and biomass flow rates were simultaneously controlled for different
SBR values keeping residence time constant. At 8000C, using legume straw
as the substrate, H2 yield peaked at SBR (mass basis) 0.6 to 40.3% (volume
fraction), reporting significant reduction in tar from 66.6 g/Nm3 at SBR of 0 to
23.1 g/Nm3 at SBR of 0.6. Reduction in char residue is reported with increase
in SBR keeping temperature constant at 8000C, resulting in 5.5 % char
residue at SBR of 0 and 2.8 % at SBR of 0.6. Increase in syngas and H2 yield
with reduction in tar and char residue is reported with increase in temperature.
Keeping the SBR (mass basis) constant at 0.6, temperature was varied and
significant reduction in tar and char residue is reported. Tar content in syngas
got reduced from 62.8 g/Nm3 at 7500C to 3.7 g/Nm3 at 8500C while char
residue reduced from 7% to less than 2% in the same temperature range.
Dalian University of Technology, China inferred that addition of steam favored
tar and char reduction and subsequent increase in syngas and H2 yield due to
tar steam reforming, cracking and char gasification enhanced by higher
reaction rates at higher temperature.
Results from the previous work suggest the choice of gasification over
pyrolysis for higher hydrogen yield and efficiency. The literature has indeed
provided details on the various thermo-chemical conversion processes,
behavior of different reactor configurations and influence of various process
parameters like SBR, ER and temperature on hydrogen yield and overall
performance. It must be emphasized that the thermochemical conversion of
biomass to syngas, rich in hydrogen is one of the efficient processes. Steam
gasification of biomass has been studied in a batch reactor under the
controlled conditions but less exploited in a fixed bed reactor for continuous
59
hydrogen production. Further, the results from the literature indicate low
hydrogen yield and issues arising from the gas contaminated with higher
molecular weight compounds, i.e., the “tar”, inducing difficulty in separating
hydrogen from the syngas mixture.
Depending upon the type of fuels used, there are different kinds of
gasifier, differing in design. All these processes can be operated at ambient or
increased pressure and serve the purpose of thermo-chemical conversion of
solid biomass. Five major types of gasifiers are- fixed-bed updraft, fixed-bed
downdraft, fixed-bed cross-draft, bubbling fluidized bed, and circulating
fluidized bed gasifiers. This classification is based on the means of supporting
the biomass in the reactor vessel, the direction of flow of both the biomass
and oxidant, and the way heat is supplied to the reactor. Fixed bed gasifiers
are typically simpler, less expensive, and produce a lower heat content
producer gas. Fluidized bed gasifiers are complicated, expensive, and
produce a gas with a higher heating value. Table 3.1 compares the
advantages and limitations of different type of gasifier designs.
Table 3.1: Relative advantages and disadvantages of different types of
gasifier
Gasifier Advantages Disadvantages
Updraft
fixed bed
Mature for small-scale heat
applications
Can handle high moisture
No carbon in ash
Feed size limits
High tar yields
Scale limitations
Low heating value gas
Slag formation
Downdraft
fixed bed
Small-scale applications
Low particulates and low tar
Feed size limits
Scale limitations
Low heating value gas
Moisture-sensitive
Bubbling
fluid bed
Large-scale applications
Feed characteristics
Direct/indirect heating
Higher heating value gas
Medium tar yield
Higher particle loading
Circulating
fluid bed
Large-scale applications
Feed characteristics
Higher heating value gas
Medium tar yield
Higher particle loading
Entrained
flow fluid
Can be scaled up
Low tar formation
Low methane content gas
Higher heating value gas
Large amount of carrier
gas
Higher particle loading
particle size limits
60
The fixed bed gasifiers are broadly classified as updraft, downdraft and
cross draft depending on the direction of air flow. Downdraft type of gasifier, in
which the fuel and air move downwards, is widely used because it generates
combustible gas with low tar content. The reactor design used until recently
was the closed top, with the upper portion of the reactor acting as a storage
bin for the fuel. The air is allowed to enter at the lower part, which generally
contains charcoal. The developmental work at the Indian Institute of Science,
Bangalore (IISc) on wood gasifier has resulted in a design with an open top
with air entering both at the top and at the bottom through air nozzles. This
feature has resulted in a design which can handle wood chips of higher
moisture content up to 25%, and produce gas with low tar levels (< 30 ppm).
The low tar level is due to the stratification of the of the fuel bed helping in
maintaining a large bed volume at high temperature. In steady operation, the
heat from the combustion zone near the air nozzles is transferred by radiation,
conduction and convection upwards causing wood chips to pyrolyse and
loose 70-80% of its weight. These pyrolysed gases burn with air to form CO2
and H2O raising the temperature to 1000-11000C.The product gas from the
combustion zone further undergoes the reduction reactions with char, to
generate combustible products like CO, H2 and CH4.
3.2.6 Exergy and Energy Analysis
Apart from the demand and usefulness, energy efficiency is one of the
most important criteria to assess the performance and sustainability of any
technology. In the gasification process, the first law of thermodynamics
permits conservation of the total energy in the conversion of solid fuel to
gaseous fuel and the second law restricts the availability of energy (exergy)
transformed to useful form. In the case of gasification process, evolution of
gaseous species increases the entropy and introduces irreversibility in the
overall thermo-chemical conversion process. During the conversion of solid
fuel to gaseous fuel, apart from the process irreversibility, the transformation
of chemical energy in the solid fuel partly to thermal energy as sensible heat
cannot be converted to the desired output i.e., chemical enthalpy in the
gaseous species. Evaluating the energy efficiency based on the energy output
to the energy input and identifying the energy loss from the system to the
environment is appropriate while considering the device. This approach may
not be sufficient while evaluating the process and the device together as a
system. Identifying the internal losses arising due to the irreversibility is
important towards understanding any energy conversion process and
probably helps in redesigning the system elements. Exergy analysis thus
helps in evaluating the conversion process and provides an insight towards
optimizing, by minimizing the losses, if any.
61
The exergy efficiency of a fast pyrolysis bio-oil production plant was
analyzed using Aspen Plus software. Based on this analysis it was found that
the exergy efficiency is 71.2% and the components for the exergy losses were
also identified. The areas that had been identified for improvement were
biomass drier, milling process for size reduction and heat exchanger used for
pre-heating the combustion air.
In the area of biomass gasification, researchers have performed exergy
analysis based on equilibrium analysis using Engineering Equation Solver
(EES) software. With the focus on H2 production, from a gasifier reactor of
0.08 m diameter and 0.5 m height using sawdust as the fuel, exergy and
energy efficiencies were estimated. The heat loss from the reactor was
modeled assuming isothermal condition. Tar, generally an issue for
gasification process and its utilization, was considered as a useful product
(fuel) and modeled as benzene molecule in the system. Effects of varying the
SBR (steam to biomass ratio) from 0.2 to 0.6 were studied, by varying steam
flow rate from 4.5 kg/s to 6.3 kg/s and biomass feed rate from 10 kg/s to 32
kg/s was considered. In the analysis, temperature was varied between 700
and 12000C and its influence on the H2 yield, exergy and energy efficiency
was also studied. The maximum exergy efficiency reported is about 65% with
minimum near SBR of 0.4.It has been shown that maximum specific entropy
generation is between 0.37 and 0.42.The lower value of the exergy efficiency
has been argued due to the increase in internal irreversibility with the varying
SBR. H2 yield was saturated at around SBR of 0.7. It is evident that in the
temperature range of 700-12000C, char-steam reaction plays a significant role
and H2 yield increases significantly till carbon boundary point (at SBR of 1.5).
Carbon boundary at SBR of 1.3 has been reported in another study. The
equilibrium values at higher SBR’s are not used in the analysis performed
using EES software.
Extensive analysis was carried out on the availability and irreversibility
of the biomass gasification process. The exergy efficiencies of air and steam
gasification with pyrolysis were compared. Equilibrium studies were employed
using non-stoichiometric method based on minimizing the Gibbs free energy.
Steam gasification proved to be a more efficient process compared to air
gasification and pyrolysis. Steam gasification efficiency was reported as
87.2% compared to 80.5% for air gasification. In the case of pyrolysis, the
efficiency was 76.8%. The physical, chemical exergy and sensible enthalpy
of gas and their variation with SBR and ER were also analyzed. In the case
of air gasification, carbon boundary was identified at ER of 0.25 beyond which
no carbon is available for gasification. Beyond the carbon boundary point, the
efficiency decreased and losses were credited to oxidation of fuel gas to CO2
and H2O leading to higher sensible heat and lower chemical energy in the
product gas. Similarly, in the case of steam gasification, carbon boundary was
62
identified at SBR of 1.3 beyond which introducing extra steam led to loss in
input energy used in steam generation. The coupling of exothermic oxidation
of carbon with endothermic water-gas and Boudouard reaction was argued for
the better efficiency of gasification over pyrolysis. The researchers have not
been ableto clearly identify reasons towards higher efficiency achieved in the
case of steam gasification over air gasification.
Thermodynamic analysis was conducted for oxygen enriched air
gasification of pine wood. The oxygen fraction in gasifying media was
increased from ambient condition (21% O2) to 40% O2 on the mole basis; the
balance being N2. Increase in exergy and energy efficiencies with O2 fraction
was observed. Exergy efficiency of 76% with 21% O2 increased to over 83%
with 40% O2 while H2 and CO mole fractions in the product gas decreased
from 22% to 11% and 19% to 14% respectively. Increase in reaction zone
temperature with increase in O2 fraction was cited as the reason for higher
efficiencies. Specific reasons towards the reduction of H2 and CO with
increase in O2percent were not discussed. The higher efficiencies at higher
O2fractions seems inconsistent based on the analysis of exergy and energy
efficiencies with the variation in temperature.
It is evident from the literature on the exergy and energy analysis of
gasification systems that largely equilibrium analysis based results have been
used. The heterogeneous reaction system during gasification is very complex
and it cannot be approximated with the thermodynamic equilibrium model.
The gas composition, quality and hence the efficiency of a gasification system
depends significantly on the residence time of the reacting species at the
given temperature which inherently depends on the reactor geometry, design
and process parameters. The heterogeneous reactions that occur inside the
reactor are both diffusion and kinetic limited depending upon the reactants.
3.2.7 National Status (Including Commercialization Efforts by Industry)
The development of the technology (internationally), to harness this
route has taken place in spurts. The most intensive efforts were put during the
Second World War to meet the scarcity of petroleum sources for transport
needs of the civilian and military sectors. Some of the most studies on wood
gasifierswere basic as well as developmental related.
In India, during the initial developmental efforts, Department of Non-
conventional Energy Sources (now MNRE) took an important decision to field
test the technology developed by various research and industrial groups. This
was carried out during 1997 to 2000. The major emphasis was on the water
pumping application in the range of 5 to 50 HP. Around 1700 systems (35
63
MW equivalent) were installed in field under the MNRE’s demonstration
program on biomass gasification.
There has been an activity for developing reliable industrial package for
both power generation and thermal application in the later period of the year
2000. In the power generation sector, the emphasis shifted from dual fuel to
pure gas engine mode; in order to compete with the grid costs as the fossil
fuel prices increased. Gas engines could not accept producer gas as a fuel as
it was not commercially available and some of the research groups carried out
the R & D to operate engines on producer gas. While various groups
developed skills to adapt natural gas engine to operate on producer gas,
Indian Institute of Science, working with Cummins India Limited (CIL)
succeeded in developing a package for producer gas engines. Currently, CIL
would be the first Indian engine manufacturer to produce engines using
producer gas as fuel.
Apart from several other factors, MNRE’s role both in research,
development and implementation of the biomass gasification programme has
been very critical. There are only 4 – 5 groups involved both in the
development and implementation of the technology packages either directly or
using licensees. There have been differences in the technology packages
developed among these groups. M/s ASCENT, Sacramento, USA have
developed packages for woody biomass, fine biomass and a combination of
the two. A closed top gasification system has been used for conversion
process. Rice husk gasification system is designed separately to handle rice
husk as received. The Research Group at Tata Energy Research Institute has
developed technology packages for woody and briquetted biomass using
throat-less gasifier with closed top. The Sardar Patel Renewable Energy
Research Institute, Vallabh Vidhyanagar, Gujarat has been involved in the
development of technology packages for dual fuel and thermal application,
using both forced and natural drafts depending upon the requirements. Indian
Institute of Science, Bangalore has developed a multi-fuel gasification system
to accept woody biomass or biomass briquettes. The largest capacity power
plant connected to the grid using gas engines supplied by Cummins India
Limited has been built. Systems of varying capacity (up to 1 to 10 MWth) have
been developed. While there have been large numbers of gasifier systems
implemented by gasifier manufacturers, but very limited operational data is
available in the public domain for analysis and reporting, consolidating the
performance of the system/s and providing an account of operational
experience.
The IISc, Bengaluru has developed an open-top downdraft gasifier,
where residence time of gases increases inside the reactor and high
temperature of the char bed is maintained, which improves conversion
64
efficiency and reduces formation of higher molecular weight compounds.
Figure 3.1 provides an input on the use of dolomite as a bed material for fluid
bed gasification system to reduce the tar levels. It can be seen that the tar
level varies from 10 to 50g/m3 depending upon the bed material used in
typical fluid bed gasification.
Figure 3.1 Average benzene and tar concentration in per kg of dry gas
Use of air gasification system for power generation has been
established and options to biomass for various other outputs as indicated in
the Figure 3.2 which suggests various biomass conversion process to end
use energy efficiency.
It is evident that the biomass gasification based power cycle has the
conversion efficiency in the range of 40 % while the hydrogen generation
could be in the range of 60 %.
As stated earlier, very limited work has been carried out in the area of
hydrogen generation from biomass. Most of the activities are at bench scale
except some of the research carried on the existing steam gasification
platform, where a small portion of the gas is being taken through the gas train
for generating pure hydrogen. The overall yield of hydrogen is about 42 g/kg
of biomass.
The National Institute of Technology, Calicut is engaged in the
research activities of hydrogen production by thermo-chemical method in
fluidized bed gasifier under catalytic support and its utilization. Under this
activity a 7.5 kW capacity bubbling ptimizat fluidised bed biomass gasifier was
65
Figure 3.2: Biomass to fuel efficiency for various outputs from biomass
conversion processes
designed and developed for performance evaluation. The effect of process
parameters on air gasification of rice husk and air-steam gasification of saw
dust and coconut shell were studied. Stoichiometric thermodynamic
equilibrium models for air and air-steam gasification of different biomasses
were developed using MATLAB software validated with experimental data.
The developed models were used to analyse the effect of various process
parameters like gasification temperature, steam to biomass ratio and
equivalence ratio on gas composition, lower heating value and yield of syngas
and first and second law efficiencies. An Eulerian-Eulerian model for air-
steam gasification of sawdust was also developed using Fluent13 software.
The particle motion inside the reactor was optimized using various drag laws
derived from Kinetic Theory of Granular Flow. In these models biomass
pyrolysis was not considered.
3.2.8 Action Plan
3.2.8.1 Gap Analysis & Strategy to Bridge the Gap with Time Frame
In the recent times the focus at MNRE has been on generating
hydrogen rich syngas through thermo-chemical conversion of biomass.
Couple of research projects has been sponsored in this sector with the focus
on hydrogen production. In view of the abundant availability of biomass in the
country, work in this area needs to be consolidated and continued to fill in the
66
existing gaps in R&D and design and demonstrate pilot/full size units within a
reasonable time frame.
As a part of the MNRE supported R&D activity, Indian Institute of
Science, Bangalore has completed a project addressing the above aspects of
hydrogen production through the thermo-chemical conversion of biomass.
This has resulted in developing a prototype to generate hydrogen rich syngas
using oxy-steam gasification.
The entire process has been optimized to generate a maximum of
about 100 g hydrogen/kg biomass. The process has also been studied to look
at possibility of generating the hydrogen rich syngas for FT process as well
with H2:CO ratio of about 2.
Syngas composition, hydrogen yield and performance parameters
were monitored with varying steam to biomass ratio and equivalence ratio.
Experiments were conducted by varying SBR from 0.75-2.7 and ER ranging
from 0.18-0.3. Figure 3.3 shows the gas analysis data of an operation of over
4 hours.
Figure 3.3 : Gas composition using oxygen and superheated steam
(SBR = 1.45, ER = 0.25)
Experiments and kinetic studies in the complex heterogeneous
reacting system have been conducted with wet wood and oxygen as well as
with dry wood and oxy-steam. Table 3.2 summarizes the data from the
experimental results using wet wood with oxygen and dry biomass with
superheated steam. Results show that using dry biomass with oxy-steam
67
improves the H2 yield, efficiency and syngas LHV compared to direct usage
of wet biomass with oxygen.
Table - 3.2 : Results, analysis and comparison while using dry biomass with
superheated steam
Dry biomass with superheated steam
H2O to biomass ratio 0.75 1 1.4 1.5 1.8 2.5 2.7
ER 0.21 0.18 0.21 0.23 0.27 0.3 0.3
H2 yield (volume
fraction, %) on dry
basis
41.8 45.2 43.1 45.2 49.6 51.7 50.5
CO yield (volume
fraction, %) on dry
basis
27.6 24.9 26.5 24.9 17 12.8 13
H2 yield (g kg-1 of
biomass) –
Experimental result
66 68 71 73 94 99 104
H2 yield (g kg-1 of
biomass) – Equilibrium
analysis result
87 88 102 101 99 107 117
Percent of H2 yield from
moisture/steam (%)
(65.5 g H2 in biomass)
21.4 20.2 28 27.7 43.7 44.3 48.1
H2/CO 1.5 1.8 1.6 1.8 2.9 4.0 3.9
LHV (MJ Nm-3) 8.9 8.6 8.8 8.7 8 7.5 7.4
H2O volume fraction in
syngas (%) 0.8 1.4 1.6 2 1.9 2.3 2.4
Fraction of heat
available through
CO+CH4 in syngas for
steam generation
4.2 2.7 2.2 1.9 1.3 0.8 0.8
Hydrogen efficiency (%)
– 73.7 63.2 67.2 63.5 70.5 61.0 63.7
Gasification efficiency
(%) – 82 73 75 74 78 67 66
Exergy efficiency (%) - 85 81 80 77 84 78 70
Using dry wood and oxy-steam as gasifying agents, 104 g hydrogen
was obtained per kg biomass compared to a maximum of 63 g H2 per kg
biomass with wet wood and oxygen. The gasification efficiency with oxy-
steam gasification was found to be 85.8% compared to 61.5% with wet
biomass at H2O to biomass ratio of 0.75. Hydrogen yield in syngas, as high
68
as, 1.3 kg/h was achieved. Syngas with LHV of as high as 8.9 MJ Nm-3 was
obtained, which is almost twice the energy content in producer gas obtained
through air gasification. At lower SBR of 0.75, the low hydrogen yield of 66 g
per kg biomass was achieved with higher gasification efficiency of 85.8%
and higher LHV of 8.9 MJ Nm-3, and with an increase in SBR, H2 yield
increased to 104 g per kg of biomass with lower efficiency of 71.5% and
LHV of 7.4 MJ Nm-3. H2 fraction in syngas and H2/CO ratio is a very critical
parameter for the conversion of syngas to liquid fuel through FT synthesis.
Varying the SBR from 0.75-2.7, hydrogen fraction in syngas has been
obtained ranging from42-52% (molar basis) and H2/CO ratio is found to be
varying from 1.5 to as high as 4. At lower SBR values, the energy content in
CO and CH4 yield is sufficient for raising steam.
With the current experience of using biomass, about 70 g pure
hydrogen can be obtained per kg biomass, which results in about 15 kg
biomass for every kg of hydrogen generated.
Having generated hydrogen rich syn-gas, it is important to utilize this
gas for hydrogen production for applications like PEM fuel cells, SOFC, etc.
This calls for purification of the syngas to various levels depending upon the
end use.
3.2.8.2 Identification of the major institutions / industry for augmenting
R&D facilities including setting-up of Centre(s) of Excellence and
suggest specific support
Indian Institute of Science, which has been carrying out research
activity in the area of bio-energy for over three decades, is well positioned to
take the responsibility of Center for Excellence in the area of biomass to
hydrogen through various routes. IISc is concentrating on thermo-chemical
route of hydrogen production – Oxy–steam gasification of biomass, which has
been demonstrated with hydrogen yield of about 100 gms per kg of biomass
use. Apart from the various thermo-chemical routes that are being
researched, IISc also has groups working in the area of engines, materials,
storage, fuel cell, etc.
71
4.0 Hydrogen Production by Electrolysis
4.1 Introduction
Hydrogen can be generated from water by electrolysis or thermolysis.
There are mainly three types of water electrolysis processes reported in
literature. These are classified as: alkaline, acidic (membrane based) and high
temperature ceramics (solid oxides) on the basis of electrolytes used. Of
these three types, development of the last one is still at the laboratory level. A
highly promising method of hydrogen production is electrolysis of water, using
power from solar photovoltaic cells (Figure 4.1).
Figure 4.1: Hydrogen generation using solar photovoltaic cells
4.1.1 Polymer Electrolyte Membrane based Water Electrolysis
Polymer electrolyte membrane (PEM) based water electrolysis offers a
number of advantages for the electrolytic production of hydrogen and oxygen
in comparison with the conventional water-alkali electrolysers, such as
ecological safety, high gas purity (more than 99.99% for hydrogen), the
possibility of producing compressed gases for direct pressurized storage
without additional power inputs and higher safety level. The membrane used
in these electrolysers is Nafion-brand perfluorinated ion-exchange membrane
of US Company DuPont (Figure 4.2). The PEM electrolysers based on solid
polymer electrolyte (SPE) technology were developed in 1966 by the General
Electric (USA) and designed for special purposes (spaceships, submarines,
72
etc.) as well as for industrial and analytical laboratory applications (in gas
chromatography).
Figure 4.2: Schematic drawing of PEM cell
Membrane based water electrolysis can be classified on the basis of
their electrolytes as alkaline (alkali / anion exchange membrane), or based on
proton / cation exchange membrane. In water electrolysis using cation
exchange membrane the oxygen and proton are generated at anode
(Equation 1), the generated proton then passes through the cation exchange
membrane and combines with electrons at the cathode to generate hydrogen
(Equation 2). The membrane acts as an electrolyte as well as a barrier for
preventing mixing of hydrogen and oxygen generated at cathode and anode
compartments respectively.
Anode (oxidation): 2 H2O(l) → O2(g) + 4 H+(aq) + 4e− --(1)
Cathode (reduction): 2 H+(aq) + 2e− → H2(g) --(2)
73
The electrode reactions in case of alkaline electrolysis are different
from those of acid electrolysis as shown in Equations 3 and 4. Here, cathodic
reduction of water generates hydrogen and hydroxyl ion (Equation 3), which
passes through an anion exchange membrane. At the anode hydroxyl ions
are oxidized (Equation 4) generating oxygen.
Anode (oxidation): 4 OH- (aq) → O2(g) + 2 H2O(l) + 4 e− --(3)
Cathode (reduction): 4 H2O(l) + 4e− → 2H2(g) + 4 OH-(aq) --(4)
The hydrogen thus produced in the process needs to be utilized in a
device that will convert it into electricity, e.g., fuel cells or it can also be utilized
in internal combustion engine.
Specifications of State-of-the-Art Alkaline and PEM Electrolysers as
reported in the NOW-study are given in Table 4.1.
Table 4.1: Specifications of State-of-the-Art Alkaline and PEM Electrolysers
as reported in the NOW-study.
Specifications Alkaline electrolysis PEM electrolysis
Cell temperature (0C) 60-80 50-80
Cell pressure (bar) <30 <30
Current density (mA/cm-2) 0.2-0.4 0.6-2.0
Cell voltage (V) 1.8-2.4 1.8-2.2
Power density (mW cm-2) <1 <4.4
Voltage efficiency HHV (%) 62-82 67-82
Specific energy consumption:
Stack (kW h Nm-3)
4.2-5.9 4.2-5.6
Specific energy consumption:
System (kW h Nm-3)
4.5-7.0 4.5-7.5
Lower partial load range (%) 20-40 0-10
Cell area (m2) >4 <0.03
H2 production rate: Stack-
system (Nm3 h-1)
<760 <10
Lifetime stack (h) <90000 <20000
Lifetime system (y) 20-30 10-20
Degradation rate (mV h-1) <3 <14
74
Advantages and Disadvantages of Alkaline and PEM Electrolysis are
given in Table 4.2.
Table 4.2: Advantages and Disadvantages of Alkaline and PEM Electrolysis.
The PEM electrolysers offer smaller, cleaner and more reliable
systems than competing electrolysis systems based on other technologies.
Alkaline electrolysers are relatively less expensive but consume more
electricity compared to PEM electrolysers wherein highly precious metals are
being used in PEM cell stack.
4.2 Alkaline Water Electrolysis
Electrolysis phenomenon was discovered by Troostwijk and Diemann
in 1789. Alkaline water electrolysis is one of the earliest methods employed
for hydrogen production. Sodium hydroxide or potassium hydroxide are used
75
as electrolytes and the cell is normally operated at about 700C. The alkaline
electrolyser cell consists of two nickel based electrodes separated by a gas-
tight diaphragm. This assembly is immersed in a liquid electrolyte that is
usually a highly concentrated aqueous solution of KOH (25–30 wt.%). It uses
microporous diaphragm to separate cathode and anode chambers. The
product gases are completely prevented from cross diffusing through
diaphragm. This results in the reduction of efficiency of the electrolyser. The
three major issues associated with alkaline electrolysers are i) low partial load
range, ii) limited current density, and iii) low operating pressure. The energy
required to produce 1 nM3 hydrogen /h is around 6 kWh. This is a matured
technology with a large number of industries supplying these electrolyser units
for a wide variety of applications. These electrolysers are less expensive as
non-noble metal catalysts are normally used. Alkaline electrolysis has been
used extensively for hydrogen production commercially up to the megawatt
range.
4.2.1 Challenges
The major challenges with alkaline water electrolyser (AWE) are
corrosion related issues and poisoning of the electrolytes by inadvertent
incursion of CO2. The energy required to produce hydrogen is still high
compared to the theoretical requirements. The other issue is developing high
pressure systems. Present method involves a separate receiver and
compressor sections in the electrolysis plant. This requires development of
polymeric membranes with anion exchange capability.
4.2.2 Current Technology
State of the Art Alkaline Electrolyser, Efficiency: 60-70% (LHV)
Operating temperature: up to 80oC
Operating pressure: 1 – 25 atm
Cost: ~$1000 - 2500/kW
4.2.3 Future Technology: Increasing the Capacity & Efficiency and
Reduction in Cost
System efficiency should reach 70-80% (LHV) by advanced
electrolyser technology
Industrial size electrolyser (MW level)
Cost should be reduced to $300 - 500/kW (Cost of Hydrogen at $2/kg)
76
4.3 Polymer Electrolyte Membrane (PEM) based Water Electrolysis
The drawbacks of alkaline electrolysers were overcome by the
development of solid polymer electrolyte concept by General Electric, USA, in
the 1960’s. The membranes used were sulfonated polystyrene membrane.
This concept is also referred to as proton exchange membrane or polymer
electrolyte membrane (both with the acronym PEM) water electrolysis, and
less frequently as solid polymer electrolyte (SPE) water electrolysis. The
polymeric membrane based water electrolysers till now have used cation
exchange membrane. Water electrolysis with a polymer electrolyte membrane
(PEM) cell possesses certain advantages compared with the classical alkaline
process like increased energy efficiency and specific production capacity and
simplicity in construction with a solid electrolyte operating at a low
temperature. Direct application to water electrolysis was not possible at that
time because available Solid polymer electrolytes (SPEs) were lacking
sufficient chemical stability. This was mainly due to very oxidizing conditions
found at the anode of water electrolyser where oxygen is evolved at high
electrode potential values (close to +2 V vs. NHE). At the end of the sixties,
more stable sulfonated tetrafluoroethylene based fluoropolymer-copolymers,
(E.I. DuPont Co., Nafion®) products were made available for water
electrolysis applications. This membrane exhibits high chemical stability both
in strong oxidizing and reducing conditions up to 1250C.
Ultra-pure water is fed to the anode compartment of the electrolysis
cell, which is made of porous titanium and activated by a mixed noble metal
oxide catalyst. The membrane conducts hydrated protons from the anode to
the cathode side. Appropriate swelling procedures have led to low ohmic
resistances enabling high current density of the cells. The standard
membrane material used in PEM water electrolysis units is Nafion® 117 and
is manufactured by DuPont, USA. The cathode of such an electrolyser
consists of a porous current collector with either Pt or, in more recent designs,
a mixed oxide as electrocatalyst. Individual cells are stacked into bipolar
modules with titanium based separator plates providing the manifolds for
water feed and gas evacuation.
The polymer electrolyte membrane (Nafion, Fumasep) have high
proton conductivity, low gas crossover, compact system design and high
pressure operation. The low membrane thickness (~20-300 m thick) is in part
the reason for many of the advantages of the solid polymer electrolyte.
PEM electrolysers can operate at much higher current densities,
capable of achieving values above 2 A cm-2, this reduces the operational
costs and potentially the overall cost of electrolysis (Tables 4.1 and 4.2).
Ohmic losses limit maximum achievable current densities, with a thin
77
membrane capable of providing good proton conductivity (0.1 - 0.02 S cm-1),
higher current densities can be achieved. The solid polymer membrane allows
for a thinner electrolyte than the alkaline electrolysers.
The low gas crossover rate of the polymer electrolyte membrane
results in yielding hydrogen with high purity, as described in Table 4.2 and
allows for the PEM electrolyser to work under a wide range of power input.
This is due to the fact that the proton transport across the membrane
responds quickly to the power input, not delayed by inertia as in liquid
electrolytes. As discussed above, in alkaline electrolysers operating at low
load, the rate of hydrogen and oxygen production reduces while the hydrogen
permeability through the diaphragm remains constant, yielding a larger
concentration of hydrogen on the anode (oxygen) side thus creating a
hazardous and less efficient conditions. In contrast with the alkaline
electrolysis, PEM electrolysis covers practically the full nominal power density
range (10-100%). PEM electrolysis could reach values over 100% of nominal
rated power density, where the nominal rated power density is derived from a
fixed current density and its corresponding cell voltage. This is due to low
permeability of hydrogen through Nafion (less than 1.25 x 10-4 cm3s-1cm-2 for
Nafion- 117, standard pressure, 800C, 2 mA cm-2).
4.3.1 Drawbacks
Problems related to higher operational pressures in PEM electrolysis
are:
1. Cross-permeation phenomenon, which increases with pressure.
2. PEM membranes being highly acidic are corrosive and require
use of distinct materials. These materials must not only resist the
harsh corrosive low pH condition (pH ~ 2), but also sustain the
high applied over-voltage (~2 V), especially at high current
densities.
3. The catalysts used, current collectors and separator plates also
need to be corrosion resistive.
4. Only a few materials can be selected in this harsh environment,
such as noble catalysts (platinum group metals-PGM e.g. Pt, Ir
and Ru), titanium based current collectors and separator plates
(Figure 4.3).
78
Figure 4.3: Component overview for a typical PEM water electrolyser.
Numbers of publications as a percentage of total publications directly
related to PEM water electrolysis over the years including the percentage
published related specifically to modeling (source: ISI web of knowledge) are
given in Figure 4.4.
79
Figure 4.4 : Number of publications as a percentage of total publications
directly related to PEM water electrolysis over the years
including the percentage published related specifically to
modeling (source: ISI web of knowledge).
Performance range of published polarization performance curves from
2010 to 2012 for a PEM electrolysis single cell operating with Ir anode, Pt
cathode, and Nafion membrane at 800C is given in Figure 4.5.
Figure 4.5 : Performance range of published polarization performance curves
from 2010 to 2012 for a PEM electrolysis single cell operating
with Ir anode, Pt cathode, and Nafion membrane at 80oC
80
4.4 Hydrogen Utilization
Fuel cells have emerged as an alternative source of energy/energy
conversion devices in portable as well as stationary mode. A variety of fuel
cells such as phosphoric acid fuel cell (PAFC), alkaline fuel cell (AFC),
molten carbonate fuel cell (MCFC), solid oxide fuel cell (SOFC) etc. have
been developed and a few of them are commercially available. Other than
PAFC, all the commercially available fuel cells such as MCFC or SOFC
operate at high temperatures and therefore their use remains limited to
stationary power generation applications. Electrolyte leakage is a major
drawback of the liquid electrolyte fuel cells. Proton Exchange
Membrane(PEM) Fuel Cells otherwise known as solid polymer electrolyte fuel
cells can operate at temperatures close to 80oC has large number of
applications in civil, aviation and military areas both in portable and stationary
power generation mode. Constant research and development activities across
different laboratories of the world are in progress to prepare cost effective
eco-friendly membranes to make affordable PEMFCs.
4.5 High Temperature Water Electrolyser (HTWE)
Using solid oxide fuel cells (SOFC) in the reverse mode is a recent
trend in hydrogen generation. The HTWE has an advantage over alkaline and
PEM electrolysers, because they can achieve a higher efficiency and lower
capital costs over a wider range of current densities and cell voltage. The high
temperature electrolysis splits steam at a temperature above 800oC. This
process uses calcium and yttrium stabilised zirconium oxide (YSZ)
membranes. Operation of the cell at high temperatures (900–1000°C) reduces
the amount of electricity needed to produce hydrogen by about 30% as
compared to electrolysis process at room temperature. Electricity consumed
is about 2.6-3.5 kWh/Nm3 of hydrogen produced. Nuclear reactors operating
in the same temperature range are ideally suited for this purpose.
4.6 International Status
International status of the published work available in open literature is
summarized in Table 4.3.
The largest existing alkaline electrolysis plants are: KIMA fertilizer plant
in Aswan, Egypt with a capacity of 160 MW and 132 modules, and a 7 module
22 MW plant in Peru (pressurized operation). Another highly modularised unit
is the Brown Boveri electrolyser, which can produce hydrogen at a rate of
about 4–300 m3/h.
81
Table 4.3: List of Companies Manufacturing Alkaline Electrolysers
Manufacturer Cell Type Rated
production
(Nm3/h)
Location
AccaGen
Avalence
Claind
ELT
ELT
Erredue.
NEL Hydrogen
Hydrogenics
H2 Logic
Idroenergy
Industrie Haute
Technologie
Linde
PIEL, division of ILT
Technology
Sagim
Teledyne Energy
Systems
Norsk Hydro ( 0.5 to1
bar, 61-72 LHV
efficiency)
Stuat Energy ( 1 to 25
bar ; 73-75% LHV
efficiency)
alkaline (bipolar)
alkaline (monopolar)
alkaline (bipolar)
alkaline (bipolar)
alkaline (bipolar)
alkaline (bipolar)
alkaline (bipolar)
alkaline (bipolar)
alkaline (bipolar)
alkaline (bipolar)
alkaline (bipolar)
alkaline (bipolar)
alkaline (bipolar)
alkaline (monopolar)
alkaline (bipolar)
alkaline (bipolar)
alkaline (bipolar)
1-100
0.4-4.6
0.5-30
3-330
100-760
0.6-21
10-500
10-60
0.66-42.62
0.4-80
110-760
5-250
0.4-16
1-5
2.8-56
Upto 485
Upto 50
Switzerland
USA
Italy
Germany
Germany
Italy
Norway
Canada
Denmark
Italy
Switzerland
Germany
Italy
France
USA
Norway
USA
The PEM water electrolyser was developed before 1966 and
introduced by General Electric Corporation, USA. In 1979 the cells operating
at 1A.cm-2 800C at 1.8V was reported. Based on this technology high pressure
electrolysis cells were designed and tested. All these efforts were basically for
NASA, US Navy aircraft carriers and nuclear submarines for hydrogen
generation and oxygen supply for life support systems. Several types of cell
and system configurations were evaluated and an ultimate size of one cell unit
was found to be 0.23 ft2. The Nafion-120 membranes with catalysts of
platinum, platinum-iridium-tantalum etc. were used for the membrane-
electrode assembly. The preparation of the membrane–electrode composites
was very expensive. By the end of this project economic evaluation indicated
a prohibitively high cost of such units. This system was suitable only for
82
specific applications, where cost is secondary and so the technology could not
attain commercial status for large scale hydrogen generation.
Billings Energy Corporation, Provo, Utah, USA also described their
version of PEM electrolyser having Nafion membrane coated with lead-
dioxide anode and nickel cathode catalysts, the performance of which was
very poor. The cell showed about 5.0V at 400mA/cm-2 at 500psig. On using
platinum for both anode and cathode they could improve the performance to
about 3.25V at 600 mA/cm2with an efficiency of efficiency of 45%. Because of
the high loading of the noble-metal catalysts and the higher resistance of the
membranes, the efficiency and economics were far from acceptable standard.
United Technologies Corporation, East Hartford, USA was reported
to be engaged in the development of PEM electrolyser modules, probably with
the GE concept, with 22 cells of 0.23ft2 each for US navy and space
applications and also described a regenerative fuel cell unit of 1-2 kW
capacity.
ABB Switzerland was also active in the PEM electrolyser
development during 1976 to 1998. The ABB technology has been
demonstrated in two commercial versions of 100kW capacity at Stellram SA,
Nyon, Switzerland and Solar-Wasserstoff-Bayern GmbH. The general design
features are: Nafion-117 with platinum cathode catalyst and graphite current
collector and the anode was Ru-Ir mixed oxide with porous titanium anode
current collector. At 1 A.cm-2 and 800C, the cells exhibited 1.75V. Both
plants had to be stooped after three years of operation from 1987 due to the
high level of hydrogen in oxygen (>3%) and the membrane was found to have
been damaged in part of the cells. The cells were refurbished and operated till
1998. The cause of failure of the cells was found to be related to the
assembling faults causing mechanical stresses and also due to the
membrane degradation.
The Electrolysis 2000 project was initiated in France and different
aspects of the system were investigated at various laboratories during the
90’s. Laboratory cells have been tested with typical voltage of 2.1V at 1
A.cm-2. The European Commission (EC) is actively supporting different
projects within the 6th and 7th Framework Programmes. The main deliverable
of the GenHyPEM project was on the development of a PEM water
electrolyser with a hydrogen production capacity ranging from 0 up to 1
Nm3H2/hour, operating in the 0-90oC temperature range and the 1-50 bars
pressure range and this project was carried out by the Institut de
ChimieMole´culaire et des Mate´riaux, France in 2008. Apart from these
developments, many research laboratories and academic institutions and
universities are engaged in studies on both the fundamental and applied
aspects of the PEM water electrolyser system.
83
The recent reports of the commercial availability of small and medium
range PEM water electrolysers for laboratory utility and for other applications
are from three major industries.
Proton Energy Systems, USA is currently offering 0.5, 1 and 10 m3
per hour hydrogen delivery systems, suitable for power generation through
fuel cells. This may be the so called state-of the-art hydrogen generator with a
number of advanced features for safe and efficient generation of hydrogen.
The system delivers hydrogen at a high purity (99.999%) and pressure of 170
to 200 psi with an overall average energy requirement of 5.7 to 6.4 kWh/Nm3
H2 for the 1 Nm3/hr H2 generators. M/s ITM power, UK is also offering PEM
based Water electrolyser system in the range of 11- 75 Nm3 H2/h capacity.
Hamilton Sundstrand, a subsidiary of United Technology Corporation, East
Hartford, USA has reported to be offering a system containing stacks upto 65
cells of 0.23 ft2 active area, operating up to 3 A.cm-2 that can deliver hydrogen
up to 750 psig. This system is intended mainly for strategic applications.
The third report is from Fuji Electric Corporate Research and
Development, Japan is about the development of 25 dm2 PEM water
electrolyser under the WE-NET program. The electrolytic cells were fabricated
with their own experimental membranes with low equivalent weight, low
thickness & high ionic conductivity and reports a test cell performance of
1.555 to 1.58V at 1 A.cm-2 and 80oC. All the cell hardwares are based on the
most improved structure and fabrication techniques.
Siemens, FRG plans to build an electrolyser system to store wind
power as hydrogen. The system will have a peak rating of up to 6 MW. The
project, which will cost 17 million, is being financed with the support of the
German Federal Ministry of Economics and Technology as part of the Energy
Storage Funding Initiative. The system involves highly dynamic PEM high-
pressure electrolysis that is particularly suitable for high current density and
can react within milliseconds to sharp increases in power generation from
wind and solar sources.
Currently available PEM water electrolyser systems have a hydrogen
production rate that varies from 0.06 to 75 Nm³/hr. This is very low in
comparison to alkaline electrolyser production rates that have already
reached 500 Nm³/h. With regard to the lifetime, the membrane represents the
critical component of PEM system. Even though the lifetime of PEM
electrolysis systems were significantly improved in the last 10 years, it is still
limited due to the nature of solid polymer electrolyte membrane, and it is
below 20,000 h. PEM electrolysers are less mature, produced in smaller
quantities, and therefore more expensive than alkaline electrolysers. It is
expected that the lifetime will be prolonged up to 60,000h in the long term
84
predictions. Even though there is no clear relation between operating
conditions and degradation processes of the stack, in some cases operating
conditions can lead to membrane perforation.
The concept of high-temperature electrolysis production of hydrogen
from steam was investigated first in the 1980s by Dornier System GmbH,
Friedrichshafen, Postfach, Germany in the project called ‘‘High Operating
Temperature Electrolysis, HOT ELLY’’. After that Westinghouse Electric Co.
and Japan Atomic Energy Research Institute (JAERI) made efforts to carry
out HTWE experiment through tubular single cells and planar cells. Then the
research and development efforts on HTWE became slow due to the cheap
and sufficient supply of fossil energy. Now once again the HTWE technology
for hydrogen production is becoming popular again, because of two major
context changes the prospects of transition to a hydrogen-based economy
due to the shortage of fossil energy and the prospects for the development of
advanced primary energy to supply highly efficient heat sources. In 2004,
researchers at the U.S. Department of Energy’s Idaho National Laboratory
(INL) and Ceramates, Inc. of Salt Lake City, USA announced a breakthrough
development in hydrogen production from nuclear energy. They have
demonstrated a 15 kW integrated laboratory scale (ILS) facility with a
hydrogen production rate of 0.9 Nm3/h.
They achieved the highest-known production rate of hydrogen by
HTSE with an electrolysis efficiency of almost 100%. This development is
viewed as a crucial first step toward large-scale production of hydrogen from
water, rather than fossil fuels and a milestone in the hydrogen energy
research field. Department of Energy (DOE) of the United States hoped that
INL can commercially produce hydrogen production by HTSE before 2017 to
reduce the dependence of fossil fuel. In Jan, 2005, the news of large-scale
hydrogen production through HTSE by nuclear reactor was voted by 584
Chinese academicians and chosen as one of the ten biggest scientific news of
the world in 2004, which indicated the deep concern about the hydrogen and
nuclear energy development progress in China. Subsequently, GE Company,
a joint effort of University of Nevada, Las Vegas and Argonne National
Laboratory, European Union (the coordinator including European Institute for
Energy Research, Swiss Federal Laboratories for Materials Testing and
Research, Deutsches Zentrum fur Luft- und Raumfahrt and Rise National
Laboratory, the University of Iceland and Icelandic New Energy, French CEA,
Japan and Korea successively initiated HTWE research programs around
2005.
Institute of Nuclear and New Energy Technology (INET), China started
R&D projects for nuclear hydrogen production in 2005. Thermo-chemical
water splitting by an iodine-sulfur (IS) process and HTSE process using
85
SOEC are mainly concerned currently with the heat utilization system of
nuclear reactor (HTR-10). In the last three years, HTWE research group
experienced preliminary investigation, feasibility study, equipment
development and hydrogen production technology.
Cylindrical design was favored for the prototypes model in the 1980s.
Current investigations focus on planar designs. Planar type HTWE technology
is being utilised, because it has the best potential for high efficiency due to
minimised voltage and current losses. These losses also decrease with
increasing temperature.
Perflurosulfonated membranes were synthesized from
tetrafluoroethylene as the starting material. These membranes have a PTFE
like back bone with side chains terminating with sulfonic acid groups. Besides
Du Pont, Asahi Glass and Dow Chemical’s also developed similar
membranes. However, the length of the side chains and the distance between
the side chains were different (Table 4.4). The equivalent weight of these
electrolyte membranes ranged from 800 to 1200g equivalent of protons in dry
form. Thickness was in the range of 50 to 260 m. Apart from
perfluorosulfonated membrane like Nafion there are several other electrolyte
membranes made either from perfluorinated or non-fluorinated chemicals and
are commercially available. Some of these electrolyte membranes are given
in Table 4.5. The hydrophilic region having sulfonic acid groups forms clusters
in the presence of water. The overlapping clusters form a transport channel
responsible for the proton transport in the membrane. Since the proton
transport takes place through the cluster region, the conductivity is highly
sensitive to the water content of the membrane. The fluorinated polymers
have shown the best of the performance in the fuel cells (>5000 hrs of
operation). However, there is a need to develop alternate non fluorinated
polymers. Besides high cost, the fluorinated membranes contribute to
environmental burden during their preparation as well as disposal of the
polymers. It is recently reported that fluorinated compounds such as
hydrofluoric acid and other fluorinated fragments are released in the water
during operation. There has been constant effort to develop alternate
polymers by various researchers around the world and their method of
preparation is tabulated in Table 4.6.
86
Tab
le 4
.4: S
che
ma
tic s
tructu
re o
f pe
rflu
oro
su
lfo
nic
acid
me
mb
rane
s m
an
ufa
ctu
red b
y d
iffe
ren
t co
mp
an
ies.
88
Table 4.6: Different Membranes and their Detailed Description.
Sl.No. Membrane Description
Perfluorinated Membranes/Partially Fluorinated Polymers
1 Gore-Select Membrane Composite membrane; a base
material preferably made of expanded
PTFE that supports perfluorinated
sulfonic acid resin, PVA etc.
2 BAM3G (Ballard Inc) Polymerization of ,,-
trifluorostyrene and subsequent
sulfonation
Grafted Polymers
3 ,, - Trifluorostyrene
grafted membrane
Grafting of ,,-trifluorostyrene and
PTFE/ethylene copolymers
4 Styrene grafted and
sulfonated poly(vinylidene
fluoride) membranes [PVDF-
g-PSSA]
Pre-irradiation grafting of styrene onto
a matrix of PVDF after elec-tron beam
irradiation. The proton conductivity
can be increased by crosslinking with
DVB
Non-fluorinated
5 -methyl styrene blend
PVDF
Partially sulfonated -methyl styrene
composite with PVDF
6 Sulfonated poly(ether
etherketone) (SPEEK)
Direct sulfonation of PEEK in conc.
sulfuric acid medium
7 Sulfonated poly(ether
sulfone)
Partially sulfonated polysulfones
8 Sulfophenylatedpolysulfone Sulfophenylation of polysulfone
9 Methylbenzenesulfonated
PBI/methylbenzenesulfonate
poly(p- phenyleneterephthal
amide) membranes
These alkylsulfonated aromatic
polymer electrolyte posses very good
thermal stability and proton
conductivity when compared to PFSA
membranes, even above 80 ◦C
10 Sulfonated napthalenic
polyimide membrane
Based on sulfonated aromatic
diamines and dihydrides. Its
performance is similar to PFSA
11 Sulfonated poly(4-
phenoxybenzoyl-1,4-
phenylene) (SPPBP)
Derived from poly(p-phenylene) and
structurally similar to PEEK. Direct
sulfonation to produce the electrolyte.
89
12 Poly(2-acrylamido-2-
methylpropanesulfonic acid)
Made from polymerization of AMPS
monomer. AMPS monomer is made
from acrylonitrile, isobutylene and
sulfuric acid
Acid Base Blends
13 Imidazole doped sulfonated
polyetherketone (SPEK)
Complexation with imidazoles to
obtain high proton conductivities
14 Sulfonated poly(ether
etherketone) (SPEEK)-PEI
Sulfonated poly(ether etherketone)
(SPEEK)-Poly ethylene imine (PEI)
blended
15 Sulfonated poly(ether
etherketone) (SPEEK)-PBI
blend
Composite membranes based on
highly sulfonated PEEK and PBI
16 PBI-H3PO4 PBI doped with phosphoric acid
4.7 National Status
R&D on alkaline electrolysers in India dates back to early eighties.
BARC and CECRI were very active in developing materials for this type of
electrolysers as well as stacks. Compact alkaline electrolysers have been
designed and demonstrated in Chemical Engineering Group (ChEG), BARC
in the late eighties. BARC has developed water electrolysers with high
current density based on indigenously developed advanced electrolytic
modules incorporating porous nickel electrodes. A 40-cell electrolysis module
incorporating Porous Nickel Electrode operates at a high current density of
4500 A/m2 which is much higher than conventional cells in the market (1500
A/m2 or below). The electrolyser operates at 550C and 0.16 MPa to produce
10 Nm3/h of hydrogen. They have also now developed alkaline water
electrolyser of 30 Nm3/hr capacity and this technology is available for
production.
In 1990’s CSIR-CECRI had reported a new Lanthanum Barium
Manganate based oxygen evolution catalyst and Nickel-Molybdenum-Iron
based composite based cathode materials for alkaline water electrolysis. They
also developed a monopolar unit alkaline water electrolytic cell and
demonstrated the performance of 1.8 V at 300 mA.cm-2 in 6 M KOH at 303 K.
In 2008, CSIR-CECRI transferred process know-how for development
activated nickel electrode for alkaline water electrolysis to M/s Eastern
electrolyser, Noida.
Energy Research and Development Association (ERDA), Vadadora
has demonstrated the concept of wind hydrogen using commercial alkaline
water electrolyser (AWE) for practical distribution generation system in 2013.
90
This project was financially supported by MNRE. The integrated system
consisted of wind turbine (2X5kw), alkaline water electrolyser (1.1Nm3/hr),
hydrogen storage tank (1Nm3, at 5kg/cm2), battery bank (6x 200Ah at 12 V)
and IC engine (650VA) and it was installed at Savli (about 30 km away from
Vadodara, Gujarat). The battery was used to provide consistent electrical
power output and avoid short term intermittent fluctuations. Hydrogen fuelled
IC engine was operated when wind along with battery is not able to meet the
load demand.
The National Institute of Solar Energy, Gwalpahari, Gurgaon has
installed a 120 kW solar photovoltaic systems to produce electricity for
generation of hydrogen through the water electrolyser and is geared up to
demonstrate and evaluate the performance of various technologies of
hydrogen energy. The hydrogen, so generated will be stored in high pressure
cylinders. As and when required, it would be utilized for stationary power
generation through fuel cell and dispensed through the dispenser unit into
hydrogen fuelled vehicles (3-wheelers & 4-wheelers), meant for
demonstration.
The following companies are reported to be engaged in manufacturing
AWE for various industrial applications:
Company Production capacity
M/s. Sam Gas Projects Pvt. Ltd., Ghaziabad -
201 015, Uttar Pradesh
M/s. Rak Din Engineers, New Delhi
M/s. Vaayu Tech Engineering, Ghaziabad, Uttar
Pradesh
M/s. S. S. Gas Lab Asia, Delhi - 110 095
M/s. Vemag Engineers Private Limited, Baroda,
Gujarat
M/s. Eastern Electrolyser limited, Noida, Uttar
Pradesh 201301
1 to 50 Nm3 / h
0.072Nm3/h
50 Nm3/h
10Nm3/h
1-50 Nm3/h
--
The CSIR-CECRI developed a PEM based hydrogen production
(capacity 40 and 80 litres/h) water electrolyser system under a MNRE funded
project during 2003-2006. Subsequently they have developed 1.0 and 5.0
Nm3/hr capacity PEM water electrolyser under 11th Five year plan CSIR
Network Project during 2012 and demonstrated the same with the energy
consumption of 5.75 kWh/Nm3 of hydrogen. The electrolyser was designed
using circular type platinum coated titanium flow field plate, platinum black
cathode and iridium oxide anode. The developed electrolyser stack can
deliver the hydrogen at 5-10 bar pressure. Recently this technology has been
91
transferred to M/s. Eastern electrolyser, New Delhi and this company has
started to work with CSIR-CECRI for further development. In addition, CSIR-
CECRI has also demonstrated solar power integrated PEM based water
electrolyser system of 0.5 Nm3/h capacity in 2012.
SPIC Science Foundation ( SSF) was also engaged in development of
PEM based water electrolyser for hydrogen generation and developed
electrolyser stacks of capacity 500 lit/hour (0.5 Nm3/hour) Hydrogen and 1000
lit/hour (1 Nm3/hour) Hydrogen, under DST-TIFAC funded project . They used
platinised Titanium plate as bipolar plate. The proto-type 0.5 Nm3/h capacity
hydrogen generator was demonstrated at the Indian Meteorological
Department (IMD), Thiruvananthapuram in Feb’ 2006, to utilise the hydrogen
for lifting the weather balloons used to collect atmospheric data.
Centre for environment, Institute of Science and technology, JNTUH,
Hyderabad has also developed indigenous PEM based water electrolyser of
36 lit/h Hydrogen Production capacity using Nafion 115 under BRNS funded
project in 2010.
Hydrogen generation using PEMWE concepts using depolarisers have
also been reported from some Indian labs. This types of work has also been
reported from some labs in USA. For the first time, SSF developed and
demonstrated PEM based water electrolyser system, which used methanol as
a depolariser. In this method, pure hydrogen can be generated with a much
lower energy consumption compared to water electrolysis. Electrolyser stack
was developed using titanium flow field plate, carbon supported Pt-Ru and
Carbon supported Platinum catalyst for anode and cathode respectively. This
was demonstrated with the hydrogen production capacity of 60.0 lit/h under
MNRE funded project during 2006. The energy consumption for hydrogen
production was 2.0 kWh/Nm3.
In 2012, The Centre of Fuel Cell Technology, Chennai (a project of
International Advanced Research Centre for Powder Metallurgy, Hyderabad)
demonstrated of 1.0 Nm3/h hydrogen production capacity electrolyser using
similar concept but with much lower energy consumption of 1.40 kWh/Nm3. It
also demonstrated for the first time use of carbon based materials in its
construction and thus redcuing the capaital cost tredomnously. ARCI-CFCT is
carrying out a large amount of work in identifying suitable depolarisers, which
can redcue the cost of hydrogen .
Sea water electrolsyis to produce hydrogen is being pursued at CSIR-
CECRI and the Centre of Fuel Cell Technology, Chennai. Novel
electrocatalayts have been developed . However the energy cost remains still
high .
92
M/s. MVS engineering Ltd , New Delhi offer turnkey supply for PEM
technology in partnership with proton onsite (USA) for customers looking for
non-alkaline solution for hydrogen generation by water electrolysis.
Indian Oil’s R&D Centre recently commissioned India’s first Hydrogen
fuel dispensing station at its R&D Centre at Faridabad. The pilot station
provides a hands-on experience with on-site Hydrogen production, storage,
distribution and supply. The hydrogen is being produced by water electrolysis
method using imported PEM electrolyser system.
In general, the production of hydrogen through electrolysis of water is a
highly energy intensive method (4.5-6.5 kWh/Nm3). Because of its high
energy consumption and also of the quite substantial investment, water
electrolysis technology is not widely used in India for commercial purposes.
The challenges for widespread use of water electrolysis are also the
durability.
BARC has a roadmap for development of solid oxide fuel cell and
development of materials and methods are underway for SOFC power packs.
They have a plan to utilise this development for the development of High
temperature steam electrolyser of 1.0 Nm3/h hydrogen production capacity for
technology demonstration purposes. Development of proton conducting high
temperature materials is another major R&D thrust. Besides BARC, CGCRI,
IIT-D has initiated some work in this area recently.
4.8 Gap Analysis & Strategy to Bridge the Gap
Identification of projects and prioritize them for support with the result
oriented targets.
Identification of the major institutions / industry for augmenting R&D
facilities including setting-up of centre(S) of excellence and suggest
specific support.
Partnership with foreign institutions including technology adaption from
abroad.
Identification of the institutions for setting up of demonstration plants.
Identification of institutions / industry to work on PPP model for
commercialization of the developed processes.
Identification of technologies for adoption in specific applications with
time line.
The electrolyser system consists of various subsystems like
electrochemical stack, power rectifiers, control systems, instrumentation for
monitoring various processes, water purification, pumps, multistage
compressors, pressure vessels, and multiple number of other engineering
93
subsystems involved while integration as per customer requirements to
develop complete system. Except for the electrochemical stack, couple of
PSU’s in India has core strength for manufacturing majority of aforementioned
subsystems and very much capable in system engineering. Imported
electrolyser stacks in different combinations may be used and integration can
be carried in the country.
4.9 Action Plan
Development of alternate solid polymer electrolytes that are stable in
the electrolysis cells more than 5000 hours of operation would be of desirable.
The SPE is either acid or alkaline based, the acid based electrolysis system
requires noble metal catalysts, and alkaline membrane based electrolysis
require cheaper electro-catalyst like nickel. It is ideal to have alkaline
membranes based water electrolysis system that works on the solar energy
derived from solar cells. However, presently alkaline based SPE faces
numerous challenges such as chemical stability in the electrochemical device.
These challenges are lesser for either phosphoric acid based electrolysis cells
or alkali based electrolysis systems using diaphragm. Due to this the following
path is suggested with an idea of immediate goals of onsite hydrogen
production using presently available technology and replacement of the
traditional technology with the membrane based electrolyser in a phase wise
manner. Following steps are envisaged.
(i) Solar energy based
(a) Acid based electrolysis system
(b) Alkali based electrolysis system
(ii) Development of electrolysers based on indigenous acid based SPE
(iii) Development of alternate alkaline membrane
(iv) Development of alkaline SPE based electrolyte system
(v) Replacement of traditional systems as in 1 by the new membrane
based system
4.10 Possible Incentives to Promote Industry Participation
Industry participation is the most essential factor for the successful
implementation as well as utilisation of the hydrogen produced using the
electrolysis method. Currently industry uses other methods for the production
of hydrogen; such industries can earn carbon credits by use of electrolysis
based hydrogen production.
(i) To begin with government can set up few demonstration plants in
an industrial area to augment the hydrogen produced by these
industries for their own production.
94
(ii) A comparative study of this method with the age old methods can
carried out and an educative program can be undertaken to show
the techno-economic feasibility of the electrolysis method.
(iii) Subsidy may be provided or the industry may earn carbon credits
for putting up such plants.
4.11 Summary & Conclusions
Solid polymer electrolyte (SPE) based electrolysis process is a clean
process of hydrogen production when coupled with photovoltaic based solar
cells. Development of solid polymer electrolytes both acid and alkali based
would be the key for successful development of these systems. Alkali based
electrolytes are preferred over the acid based ones due to the use of non-
noble catalysts, however alkali based SPE faces challenges such as chemical
stability in the electrochemical system. The acid SPE based electrolyser may
be deployed on a small scale in a distributed hydrogen production systems
both in industry as well as for remote areas. It is suggested to setup hydrogen
production plants based on presently available electrolysers which can be
manufactured in India and then replace these conventional electrolyser with
the SPE based electrolysers in a phase wise manner. This will ensure the
successful deployment of technology in time to come.
4.12 Cost Estimate of Hydrogen Generation
Hydrogen Generation on a 1 MW system
Assumptions
Utilization
factor
75% Plug
Cost of
Electricity ($/kW) $ 0.12 Plug
Efficiency % 77% Calculated
Efficiency kWh/kg 51.0 Plug
CapEx
10 year program
kg / Day Cost kg of H2 $ / kg
1 MW System 450 $ 1,975,000 1,231,875 1.603247
Opex
Cost Total Cost $ / kg
Maintenance per year $ 35,000 $ 350,000 0.28412
Spare Parts over proyect $ 60,000 $ 600,000 0.487062
Electrical Cost
$ 753,908 $ 7,539,075 $ 6.12
Water Cost
$ 54,750 $ 547,500 $ 0.44
Total Cost of per kg of H2 produced $ 8.94
97
5.0 Bio-Hydrogen and Bio-Methane Production
5.1 Biological Hydrogen production process has gained importance in
recent years. In early 1990s biological hydrogen production came in lime light
in energy policy of many government institutions throughout the world.
Biological H2 production takes place mainly at ambient temperature and
atmospheric pressure which makes this process less energy intensive than
other conventional processes (chemical or electrochemical process).
Microbial species capable of producing H2 belong to different taxonomic and
physiological types. Pivotal enzyme complex involved in H2 production are
hydrogenase or nitrogenase. These enzymes regulate the hydrogen
production process in prokaryotes and some eukaryotic organisms including
green algae. The excess electrons generated during catabolism inside the
cells are disposed in the form of H2 by the action of hydrogenase protein.
The biohydrogen production process can be classified into two broad
group viz. light dependent and light independent process. Light mediated
processes include direct or indirect biophotolysis performed by algal species
and photo-fermentation performed by purple non-sulphur bacteria. Dark
fermentation is performed by heterotrophic organotrophic microbes. The algae
use their photo-synthetic apparatus and solar energy to convert water into
chemical energy. In this process, oxygen is produced as by-product. This
oxygen acts as inhibitor of enzyme system responsible for hydrogen
production.
The coupling of two separate stages of micro-algal metabolism i.e
photosynthesis and fermentation for hydrogen production is termed as indirect
‘bio-photolysis'. The fixation of CO2 into storage carbohydrates (e.g. starch in
green algae, glycogen in cyanobacteria) is coupled with fermentation of these
stored energy reserve for H2 production under anaerobic conditions. This
process is not marred with the problem of oxygen accumulation. Thus it is
considered more efficient than direct photolysis of water. To compete with
alternatives sources of renewable H2 production process, such as photovoltaic
electrolysis, the bio-photolysis processes must achieve close to an overall
10% solar energy conversion efficiency. To achieve high solar conversion
efficiencies, certain biotechnological steps are required. One of such steps
could be reduction of number of light harvesting pigments or use of
metabolically engineered cell that are more efficient in fermentation of stored
carbohydrates to H2.Improvement of bioprocess parameters could lead to the
solution of scaled up operation of photo bioreactor for hydrogen production.
Among all the biological H2 production processes, dark fermentation
shows highest H2 production rates. This process holds promise for
commercialization. If evolution of microbes is considered, as the availability of
98
organic matter on earth varied, the fermentative microbes capable of H2
production i.e. fermentative bacteria evolved with the appearance of organic
material on earth. These microbes adapted themselves to different growth
conditions (mesophilic temperatures, thermophilic temperatures, etc.) and
complexity of the substrate. They are heterotrophic in nature and produce H2
under anaerobic conditions. The metabolism of these microbes involves
utilization of simple sugars and production of electron donors in terms of
NADH. The substrate-level phosphorylation is the only way of ATP production
under anaerobic conditions. The NADH thus produced is used by Fe-Fe
H2ase enzyme complex to produce molecular hydrogen in obligate
anaerobes. In case of facultative anaerobes, the format lyase enzyme breaks
format to molecular hydrogen and carbon dioxide. Format lyase is also known
as Ni-Fe hydrogenase whose turnover number is lower than Fe-Fe H2ase.
Thus obligate anaerobes are reported as highest H2 producing organisms.
Theoretical maximum yield for hydrogen production is 4 moles / mole of
glucose. Fermentative microbes growing at thermophilic temperatures are
reported to produce hydrogen at high rate. There are many advantages of
thermophilic bioH2 production viz. at thermophilic temperature the
thermodynamics of H2 production is more favorable. Moreover, temperatures
greater than 600C lead to pathogen destruction and reduce the chances of
unwanted contaminations. Very few end-metabolites are produced under
thermophilic regime. These end-metabolites are generally composed of
ethanol, acetate, butyrate, propionate, etc. The presence of these molecules
in the spent media leads to extra burden of waste disposal.
The photoheterotrophic process converts the volatile fatty acid rich
spent media of dark fermentation to hydrogen. Photo-fermentative bacteria
such as Rhodopseudomonas, Rhodobactersp, Rhodospirullum sp., etc. are
the major photo-fermentative bacteria. Light intensity, light wavelength and
illumination protocol are the major factors that drive the photo-fermentation.
Theoretically, H2 production from 1 mole of acetate, propionate and butyrate
are 4, 7 and 10 moles, respectively. Thus integration of photo-fermentation
with dark fermentation was considered for the maximization of gaseous
energy recovery (Figure 5.1). But there were many operational challenges of
using photo-fermentative bacteria. One of the major problems faced was the
light shading effect generated by accumulation of pigment in the photo-
fermentative microbes. Moreover, the rate of H2 production was also
considerably low when compared with dark fermentation. Photo-bioreactor
design and scale up challenges have hampered the implementation of
integration of photo-fermentation with dark fermentation. Poor light conversion
efficiency of these organisms and requirement of external light source made
this process energy intensive.
99
Another two-stage process where bioH2 production process was
integrated with bio-methanation was also considered as a feasible option of
improvement of gaseous energy recovery. Since bio-methanation process is a
well-established process, the implementation of such integrated process holds
a lot of promise. Scaling up of biomethantion process is relatively easy and
less costly. Thus the mixture of bio-hydrogen and bio-methane can be
collectively called under the eponym of “HyMet”.
Figure 5.1 Gaseous Energy Recovery in Two-stage Integrated Process.
5.2 International status: First review on bio-hydrogen production was
published in Nature Biotechnology as “Bio-hydrogen production deserves
serious funding”. Subsequently, impetus on bio-hydrogen gained momentum
in early 21st century. Major contributors in bio-hydrogen production research
were from United States of America, Canada, Malaysia, Indonesia, Thailand,
China and India. National Renewable Energy Laboratory (NREL), Oak Ridge
USA, funded initial bio-hydrogen studies in USA. Enzymatic bio-hydrogen
production and bio-hydrogen from waste paper was the major initiative taken
by NREL. Different microbes were discovered in different parts of the world,
each having unique hydrogen production ability. Potential of E. coli in bio-
hydrogen production and its metabolic engineering was explored by
100
Hellenbeck in the year 2006. Many mesophilic species were explored for
hydrogen production. Enterobacteraerogenes was one of the commonly
studied facultative anaerobes. Obligate hydrogen producing microbes were
popular species due to their higher H2 yields. Thermophilic bio-hydrogen
research gained importance by 2004. ThermophilicClostridium thermolacticum
was reported for the first time for bio-hydrogen production. Pusan National
University, Pusan, South Korea studied Thermophilic H2 production from
glucose at 55-64oC using a continuous trickling biofilter reactor (TBR) packed
with a fibrous support matrix. The biogas composition was around 53 % of H2
and 47 +/- 4% of CO2 by volume. The thermophilic TBR is superior to most
suspended or immobilized reactor systems reported thus far. This is the first
report on continuous H2 production by a thermophilic TBR system. As time
passed on, need of renewable feedstock for bio-hydrogen production was
realized, as for bio-hydrogen to be considered as renewable energy source, it
should be produced from renewable raw materials only. The concept of waste
management coupled with energy generation was popularized. In 2003,
Logan et al. first reported the possibility of wastewater management along
with hydrogen production. Major surge in bio-hydrogen research was in the
year 2004. Dark fermentative H2 production using packed bed reactor was
first explored by Logan et al.in 2004. Up till now significant research has been
done on bioH2 production. Many studies were done in pilot scale units.
Internationally very few studies are available for commercial H2 production.
Integration of bio-hydrogen with fuel cell was first mooted by Marta S.
Basualdo in 2012.This concept still needs a serious consideration since this
technology can produce H2 in decentralized manner for low and medium level
electricity needs.
5.3 National Status
In India, first dedicated pilot-scale bio-hydrogen production unit using
distillery effluent was reported by Shri AMM Murugappa Chettiar Research
Centre (MCRC) using defined bacterial co-culture. MCRC has developed a
biological process for generation of hydrogen from sugar and distillery wastes
using the effluents at M/s. E.I.D. Parry Ltd., at Nellikuppam, Tamilnadu.
MCRC has been working on scaling this technology using a 125 m3 bioreactor
which has produced 18,000 liters of total gas per hour with about 60%
hydrogen mixed largely with CO2 and CO. Indian Institute of Technology
Kharagpur was one of the leading institutions involved in bio-hydrogen
research for more than a decade. IIT Kharagpur demonstrated high rate of
hydrogen production in packed bed reactor configuration in a pilot scale unit.
Its main emphasis was on utilization of organic wastes for energy generation.
Under the leadership of IIT Kharagpur an attempt for commercialization of bio-
hydrogen production was envisioned through the mission mode project
“Biohydogen through Biological Routes” sponsored by MNRE. IIT Kharagpur
101
is also involved in development of novel and cheap media composition which
would make the product cost effective. It is mainly focused on the
identification of cheap nitrogen sources that can replace the need of yeast
extract and tryptone in the fermentation media. Moreover, it is also involved in
waste to energy concept. Use of distillery effluent, starchy wastewater and
lingocellulosic biomass as substrates are receiving more attention. Other
collaborators in this group include institutions with varied experiences in bio-
hydrogen production. Indian Institute of Chemical Technology, Hyderabad has
developed rapid screening methodology for selecting organic waste for bio-
hydrogen production. Jawaharlal Nehru Technological Institute, Hyderabad
has developed mixed consortia from mangroves sludge and hot spring for
hydrogen production. The Tata Energy Research Institute (TERI), New Delhi
has a well-established large scale bioreactor facility for bio-hydrogen
production. It is involved in thermophilic H2 production process. Banaras
Hindu University and Allahabad University were chosen for photo-
fermentation studies.
Under a Mission Mode Project on Biological Hydrogen Production
sanctioned by MNRE in 2009, two 10 m3 capacity reactors are under
installation at IIT Kharagpur and IICT Hyderabad using distillery effluent and
kitchen waste respectively. These bio-reactors are expected to produce 30-
50 m3 of hydrogen per day. In addition, technical document for setting up an
industrial level reactor will also be developed under this project. In
collaboration with IIT Kharagpur, Naval Material Research Laboratory
(NMRL), Mumbai has been planning to integrate bio-hydrogen with chemical
fuel cells for electricity generation. Other institutions/universities such as Anna
University, Institute of Genomics and Integrative Biology India, New Delhi, etc
are also actively involved in bio-hydrogen production.
The National Institute of Technology, Raipur recently started working
on the development of Microbial Electrolytic Cellfor economic and energy
efficient bio-hydrogen production from leafy biomass by electro-hydro-
genesis.
Indian Association for the Cultivation of Science, Kolkata is working on
the development of a bio inspired catalyst that would efficiently catalyse
hydrogen evolution and give better understanding about the mechanism of the
hydrogen evolution reaction (HER) by the [Fe-Fe]- Hydrogenase enzymes
which will in turn be helpful in the development of better HER catalyst in terms
of performance and turnovers. Novel hydrogenase model complexes
(catalysts) have been synthesized with a clickable alkyne group. For robust
and successful immobilization of the catalyst onto the electrode surface, the
graphene oxide is modified with aza-amine with azide group to get aza
terminated ITO supported graphene as electrode material and the alkyne end
102
of the catalyst is clicked onto electrode with Cu(I) as the catalyst. The
catalysts so developed will be used for production of H2 from H2O.
5.4 Action Plan and Suggestions
Hydrogen production through dark fermentation has certain limitations.
Gaseous energy recovery in terms of only H2 might not be sufficient to make
this process commercially viable. Only 20 to 30 % of total energy can be
recovered through H2 production. Even though integration with photo-
fermentation, theoretically, 12 moles of H2 /mole of glucose can be recovered
but due to scaling up problem of photo-fermentation such a two-stage process
is difficult to commercialise. To make the dark fermentative hydrogen
production worthy of commercialisation, it should be integrated with the bio-
methantion process. The spent media of the dark fermentation is rich in
volatile fatty acids that would be an ideal substrate for methanogens. Bio-
methantion technologies are well established and are easy to scale up. The
integration of these two processes might lead to 50-60% gaseous energy
recovery (Figure 5.2). Most attractive point of such a process is that the
reactor used for H2 production could be used for bio-methanation. So,
separate reactor is not required. This would lead to decrease in operational
cost of the entire process. Bio-hymet production could be envisioned as
renewable source of energy only when it would be produced from renewable
sources. Any organic compound which is rich in carbohydrates, fats and
proteins could be considered as possible substrate for bio-hymet production.
The advent of technology, such as fuel cell that converts hydrogen to
electricity has infused new life to the implementation of hydrogen based
economy. The path of hydrogen economy would be realized through the
implementation of fuel cell system with the bio-hydrogen production systems.
The efficient fuel cells, that would be able to perform at ambient temperatures
and would require minimum maintenance, are the major advantages towards
their commercialization. Till now very few steps have been taken on
demonstration of integration of bio-hydrogen production with fuel cells. It
would be interesting to see the performance of continuous bio-hydrogen
production when connected to fuel cells.
The bio-hydrogen setup should be put strategically near to those
places where supply of feedstock is cheap and easily available. The electricity
generated by such process could be helpful for rural electrification.
Development of such process would lead to decentralized use of hydrogen.
103
Figure 5.2 Bio-hymet Concept for Maximum Gaseous Energy Recovery
International and National status and gaps of technologies of bio-
hydrogen production routes have been compared in Table 5.1.
Table 5.1 Comparison of Bio-hydrogen Production Routes
Techno
logy
International
Status
National
status
Technology
Gaps
Suggestions
Direct
Biophotolysis
Techno-
logical
advancement
was not
encouraged
Techno-
logical
advancemen
t was not
encourage
Expensive and
difficulty in
scaling up of
photo-
bioreactor,
inhibition of H2
production
due to oxygen
toxicity,
H2 production
rate are not
encouraging
Development of
mutant strains
resistant to O2
toxicity,
Development of
cheap material of
construction for
photobioreactors
104
Indirect
Biophotolysis
Technological
advancement
was not
encouraged
Technologic
al
advancemen
t was not
encourage
Expensive and
difficulty in
scaling up of
photobioreact
ors,
H2 production
rate are not
encouraging
Development of
strains that are
more efficient in
starch
accumulation
and
fermentation,
Development of
cheap material of
construction for
photobioreactors
Photo-
fermentation
Scale up pilot
plant of 100 L
was
developed
Lab scale
stage
Expensive and
difficulty in
scaling up of
photobioreact
ors,
Shading effect
of pigments
produced by
the microbes,
poor
photosynthetic
efficiency,
H2 production
rate are not
encouraging
Development of
mutant strains
having low
pigment content,
heterologous
over expression
of
clostridialH2ase,
Development of
cheap material of
construction for
photobioreactors
Dark
fermentation
Pre
commercial
stage
Pre
commercial
stage
Scale up
problem,
development
of large scale
bioreactors,
screening of
potential
microbes, raw
material
availability,
Storage of H2,
Purity of H2
produced is
not sufficient
to be supplied
to fuel cells
Use of
customized
packed bed
reactor systems
for high rate of
H2 production,
Use of organic
industrial and
household waste
as feedstock,
Development of
cheap gas
scrubbing
technologies
such as water
scrubbing
107
6.0 Hydrogen Production through Thermo-chemical Route
6.1 Introduction
Thermo-chemical splitting of water to produce hydrogen was
considered as one of the potential methods which can be scaled up for large
scale generation. In this context to provide quality heat for the process use of
energy sources such as nuclear and solar etc., was considered, as these
sources were being envisaged by these sources for input heat were
attracting worldwide attention. With regard to the choice of likely process
routes for development the iodine-sulfur (I-S) and copper-chlorine (Cu-Cl)
cycles were considered having potential for scale up hydrogen generation,
however, the process was complex and required multi-disciplinary approach
to develop suitable technology. Currently globally, these cycles are at different
stages of development and are yet to be commercially proven.
The iodine-sulfur (I-S) cycle is one of the most promising and efficient
thermo-chemical water splitting technologies for the massive production of
hydrogen. As competing processes, other options such as HTSE, hybrid
sulfur cycle and Cu-Cl cycle are also being studied for the production of
hydrogen.
Schematic of thermo-chemical water splitting cycle is shown in Figure
6.1.
Figure 6.1: Schematic of thermo-chemical water splitting cycle
Schematic and conditions of a typical Cu-Cl closed loop is shown in
Figure 6.2 and Figure 6.3.
108
Figure 6.2: Schematic of a typical Cu-Cl closed loop
Figure 6.3 Schematic and conditions of a typical I-S closed loop
109
6.2 International Status
Integrated I-S loop cycle has been demonstrated in the following
countries:
Country Year
USA : 1980
European Union : NA
Canada : NA
Japan : 2004
South Korea : 2009
China : 2010
India : 2013
Country wise status and plan on I-S process is discussed below.
6.2.1 United States of America: The Nuclear Energy Research Initiative
(NERI) was established with the goal to demonstrate the commercial scale
production of hydrogen using nuclear energy by 2017. The modular helium
reactor (MHR) has been suggested as the Generation IV reference concept
for nuclear hydrogen generation on the basis of either the I-S thermo-
chemical cycle or HTSE.As part of the national hydrogen research
programme, the US DOE created the Nuclear Hydrogen Initiative (NHI) with
the objective to advance nuclear energy for the support of a future hydrogen
economy. The frame was widened with the start of the International Nuclear
Energy Research Initiative (I-NERI) for bilateral or multilateral international
cooperation supporting R&D activities for Generation IV reference concept of
the NHI and the advanced fuel cycle R&D. The objectives of I-NERI include
the development and demonstration of technologies which enable the nuclear
power based production of hydrogen by non-fossil based water splitting
hydrogen production processes. The I-S cycle development project has been
taken up by an international consortium led by General Atomics and
comprising also the Sandia National Laboratory (SNL), USA and the French
Commissariat of Atomic Energy (CEA). Between 2003 and 2008, the US
DOE promoted nuclear hydrogen programmes in the USA which concentrated
on:
- Hybrid sulphur thermo-chemical cycle development at the Savannah
River National Laboratory (SRNL);
- High temperature electrolysis development at the Idaho National
Laboratory (INL);
110
- I-S process development at the General Atomics.
Through a down selection activity led by INL and carried out in 2009to
systematically evaluate and select the best technology for deployment with
NGNP (Next Generation Nuclear Plant), the HTSE was adjudged as the most
appropriate advanced nuclear hydrogen production technology that presents
the greatest potential for successful deployment and demonstration at NGNP.
But it was also stated that both Westinghouse hybrid (HyS) and I-S processes
exhibit attractive attributes for hydrogen production, which supports not
abandoning either technology for future consideration.
6.2.2 European Union: High Temperature Thermo-chemical Cycles
(HYTHEC) was a STREP (Specific Targeted Research Project) with six
partners starting in 2004 and running over almost four years. Its main
objective was to evaluate the potential of thermo-chemical processes,
focusing on the I-S cycle to be compared with the HyS cycle.
Nuclear and solar were considered as the primary energy sources, with
a maximum temperature of the process limited to 950°C. A preliminary
reference sheet of the I-S cycle has been conceptualized and optimized to a
‘reference’ flow sheet by coupling to a single 600 MW indirect cycle Very-
High-Temperature Reactor (VHTR). The reactor, fully dedicated to hydrogen
production, is designed as a ‘self-sustaining concept” delivering both
electricity to meet the plant’s own total power demand and heat to run the
Hydrogen production process at a rate of 110 t/d and an overall plant
efficiency of ~35%.
A preliminary evaluation of the hydrogen production costs based on
solar, nuclear and hybrid operation led to following results: small plants are
powered most favorably by solar energy, while nuclear plants are most
economical at high power levels (> 300 MW(th)); hybrid systems may have
their niche in the midrange of 100 to 300 MW(th).
The 2015 targets defined for high temperature thermo–electrical–
chemical processes with solar–nuclear heat sources are reduction of CO2
emissions for fossil reforming by more than 25% and hydrogen production
cost of less than €2/kg
HycycleS is a new European project that started in 2008 involving nine
European and four associated international partners. Following in the
footsteps of the HYTHEC project, the three year project HycycleS (2008–
2010) was aimed at the qualification of ceramic materials and reliability of
components for the essential reactions in thermo-chemical cycles. The focus
was on the decomposition of sulphuric acid as the central step of the hybrid-
sulphur (HyS) cycle and the I-S cycle.
111
The final aim was to bring thermochemical water splitting closer to
realization by improving the efficiency, stability, practicability and economic
viability.
6.2.3 Canada: In close cooperation with the Argonne National Laboratory
(ANL) in the USA and the University of Ontario, Institute of Technology (UOIT)
and other universities, Atomic Energy of Canada Limited (AECL) is
investigating the copper–chlorine family of thermo-chemical cycles with
maximum temperatures that can be provided by the CANDU Mark 2 SCWR
(Super Critical Water Reactor). But apart from this cycle, AECL research
includes investigating the use of direct resistive heating of catalysts for SO3
decomposition in the I-S process.
6.2.4 Japan: In recent years, JAEA has undertaken extensive R&D on the
thermo-chemical cycles based on the UT-3 and I-S processes for H2
production. It is most advanced in the study of the I-S cycle, with the
successful operation of a bench-scale facility having achieved a hydrogen
production rate of 30 NL/h in continuous closed cycle operation over one
week. This process is now considered the prime candidate for the
demonstration of nuclear assisted hydrogen generation.
The next step, which started in 2005, is the design and construction of
a pilot plant with a production rate of 30 Nm3/h of H2 under the simulated
conditions of a nuclear reactor. While the efficiency was ~10% for the bench-
scale plant, the goal for the pilot plant is ~40%.
As a backup hydrogen production method, the high temperature
electrolysis has also been investigated, but has not yet gone beyond lab-scale
testing (Figure 6.4)
Figure 6.4: Plan of proposed R&D activities
6.2.5 South Korea: The projected hydrogen economy in the Republic of
Korea requires that 25 % of total hydrogen be supplied by advanced nuclear
112
reactors by 2040. This amount of hydrogen is around 3 Mt/year and it is
expected to be produced in 50 nuclear hydrogen units. The nuclear policy in
Korea is led by its Atomic Energy Commission (AEC) which collaborates with
the Korean Institute of Energy Research (KIER), Korean Atomic Energy
Research Institute (KAERI), and the Korean Institute of Science and
Technology (KIST).
Korea launched its nuclear hydrogen program in 2004 with two targets
as under:
(1) Generation of hydrogen for fuel cell applications such as electricity
generation, passenger vehicles, and residential power and heating,
and
(2) Lowering hydrogen costs and improving efficiency of the related
processes.
The following nuclear hydrogen programs were approved by AEC:
NHDD—“Nuclear Hydrogen Development and Demonstration” program
which started after 2011 and go up to 2030
(Milestones: 2022—prototype construction, 2026—technology
demonstration, 2030—technology commercialization).
Hydrogen production program with two phases:
– I: Hydrogen production from natural gas, petroleum naphtha, and
electricity (ending in 2025)
– II: Hydrogen production from coal, nuclear energy and renewable
energy (ending in 2040)
For the reference case design of the VHTR-H2 system, an underground
VHTR reactor of 200 MW thermal output will be coupled with an I-S
cycle to generate hydrogen from water
I-S cycle development. It runs in parallel with NHDD (Nuclear
Hydrogen Development and Demonstration) and GIF (Generation IV
International Forum) programs and it has two phases:
– I: 2006–2011 for development of key technologies
– II: 2012–2017 for performance improvement and validation
I-NERI-Korea participates in the I-NERI program of DOE with joint
projects with the Idaho Nuclear Laboratory and Argonne National Laboratory.
Korea also established two major joint research agreements, namely:
113
(1) Nuclear Hydrogen Joint Development Centre (NHDC) with General
Atomics,
(2) Nuclear Hydrogen Joint Research Centre with China (via INET).
6.2.6 China: R&D on hydrogen production through water splitting using
HTGR as a process heat source was initiated in 2005 as one component of
China’s HTR-PM (High Temperature Reactor – Pebble Module)
demonstration project. Both the I-S thermo-chemical cycle and high
temperature steam electrolysis have been selected as potential processes for
nuclear hydrogen production.
Beginning with preliminary studies, the R&D programme, now part of
the HTR-PM project, will be conducted in phases as under:
– Phase one (2005–2009): verification of nuclear hydrogen production;
– Phase two (2010–2012): bench-scale testing;
– Phase three (2013–2020): pilot-scale testing, R&D on coupling
technology with reactor, nuclear hydrogen safety;
– Phase four (after 2020): commercialization of nuclear hydrogen
production.
Other countries such as Italy, South Africa and France are also working
on different thermo-chemical cycles including I-S and Cu-Cl processes.
6.3 National Status
6.3.1 Work Done by Bhabha Atomic Research Centre
R & D for the Production of Hydrogen by Splitting Water using
nuclear Heat: Successful feasibility demonstration of cyclic operation of the
process provided fillip to intensify the development effort for tackling variety of
issues like efficient integrated process schemes, equipment, materials and
analytical techniques etc. Efforts are also on to demonstrate the operation
under prototypical conditions to generate data for assessing the viability of the
process for large scale deployment.
The road map for I-S process development is shown in Figure 6.5.
114
Figure 6.5: Road Map for I-S Process
High temperature reactor based iodine-sulfur (I-S) thermo-chemical
cycle offers a promising approach to the high efficiency production of large
volumes of hydrogen from water.
The I-S cycle consists of three sections as expressed in following
equations:
SO2 + I2 + 2H2O = 2HI + H2SO4 (25 – 120oC) -------- (i)
H2SO4 = H2O + SO2 + 0.5O2 (800 – 900 oC) -------- (ii)
2HI = H2 + I2 (350-450 o C) --------- (iii)
Pilot Scale Demonstration
13 M3
H2/Hr
Bench Scale Demonstration
150 Lit H2/Hr
Demonstration with 600 MWth
HTR
80,000 M3
H2/Hr
Experimental
Validation
Material Studies
Design and
Simulation
Research
and Development
115
The Equation (i) is the Bunsen reaction where water is split by sulphur-
dioxide (SO2) & iodine (I2) at relatively low temperature. Equation (ii) is the
highest temperature reaction of the cycle where high temperature is achieved
using Nuclear (High Temperature Reactors) / Solar heat. Equation (iii) is
hydrogen iodide (HI) decomposition reaction, where HI is decomposed into
hydrogen (H2) & iodine by heating at intermediate temperatures. The I-S
process is a closed loop process as the chemicals SO2 & I2 are recycled back
to the system, water & heat are the only input and the output is hydrogen (H2)
as product and oxygen (O2) as the by-product.
Initially Bunsen reaction studies were carried out at Chemical
Technology Division of BARC to study the overall reaction kinetics. A sketch
of the apparatus used in the experiments of SO2 chemical absorption in water
containing iodine is shown in Figure 6.6.
Figure 6.6: Schematic of Bunsen Reactor Setup
The experimental results for the SO2 absorption into aqueous solution
containing iodine are shown in Figures 6.7 & 6.8.
117
Figure 6.8: Batch Time (Experimental) Vs Batch Time (Calculated)
The other reactions of I-S process require catalyst. In house catalysts are
developed and tested in BARC. Chemistry Division, BARC has developed
catalyst for sulfuric acid decomposition and Heavy Water Division, BARC has
developed catalyst for HI decomposition reaction. The test facility and
characterization is shown in the Figure 6.9& 6.10.
118
Figure 6.9: HI Decomposition Test Facility and Catalyst Characterization
Figure 6.10: Catalyst Characterization for Sulfuric Acid Section
HI Catalyst Characterized and tested at 350°C
Catalysttemperature
HI decomposition fraction
423 K%
523 K 3 %
623 K 14 %
0.4
Cr0.2Fe1.8O3 more
active than Fe2O3
SO2 yield: as a function of acid flux
Fresh catalyst
Used catalyst
119
As a first step to demonstrate the I-S process and feasibility of closing
the loop, Chemical Technology Division, BARC has initiated the efforts for the
same. The I-S closed loop system has been worked out in glass/quartz
equipment, operating at atmospheric pressure and prototypical temperature
conditions.
Figure 6.11: Layout of Closed Loop Figure 6.12: Boxed up Arrangement
Glass System (CLGS) for CLGS.
The closed loop glass setup (Figure 6.11 and Figure 6.12) is divided into 3
sections as given below:
1. Bunsen Section
a. Bunsen Reaction
b. Liquid-Liquid Separation
c. Acid Purification
2. Sulfuric Acid Section
a. Sulfuric Acid Concentration
b. Sulfuric Acid Decomposition
3. HI Section
a. HIx Distillation
b. HI Decomposition and HI Recovery
c. Hydrogen Purification
The pictures of various equipment/systems during operation are given in
Figures 6.13 to 6.17.
120
Figure 6.13: Bunsen Reactor during Operation & Liquid- Liquid Phase
Separation
Interface of two phases
122
Fig 6.16: Sulfuric Acid Concentrator and Decomposer
Fig 6.17: HI Decomposition System
The closed loop glass system is operated continuously for a period of
20 hours at the hydrogen production rate of 30 lph. India is the 5th country in
123
the world to achieve I-S closed loop operation in glass system, after USA,
Japan, China and South Korea. The Chemical Technology Division, BARC is
also pursuing the studies on Bunsen reaction and phase separation at high
pressures in Metallic Bunsen System (MBS) and sulfuric acid decomposition
studies in High Pressure Sulfuric acid Decomposition System (HSDS). This
will give substantial inputs for the closed loop metallic system at higher
pressures (Figure 6.18 and Figure 6.19).
Figure 6.18: Reactor & Separation System
124
Figure 6.19: Feed System
Schematic of Operations Envisaged in Integrated Reactor of HSDSis
given in Figure 6.20.
125
Figure 6.20: Schematic of Operations Envisaged in Integrated Reactor
of HSDS
Cut View of Integrated Reactor of HSDSis shown in Figure 6.21.
126
Figure 6. 21: Cut View of Integrated Reactor of HSDS
Heavy Water Division, BARC is working on reactive distillation route to
produce hydrogen by splitting of HI acid. Desalination Division, BARC is
working on alternate route for HI decomposition section studies using electro-
electro dialysis for concentration and membrane reactor for decomposition of
HI to produce hydrogen.Alumina Supported Silica Membraneis shown in
Figure 6.22.
Figure 6.22: Alumina Supported Silica Membrane
Membrane Reactor for HI Decomposition is shown in Figure 6.23.
127
Figure 6.23: Membrane Reactor for HI Decomposition
Chemical Technology Division, BARC has taken the initiative to carry
out the I-S process demonstration in engineering material of construction. For
that purpose Atmospheric Metallic Closed Loop (AMCL) is being taken up by
the division. The P&ID is ready for the setup. Process designing for the setup
is underway.
The Chemical Engineering Division, BARC has started working on 3-
step Copper Chlorine (Cu-Cl) process. The Chemistry Division, BARC along
with Chemical Technology Division, BARC have started working on Hybrid
Sulfur (Hy-S) process.
6.3.2 Work Done by ONGC Energy Centre
ONGCEnergy Centre (OEC) is working on sections of I-S process
through IIT-Delhi, CECRI Karaikudi. ONGC is working on Cu-Cl process
through ICT-Mumbai. They have demonstrated proof of principle experiments
and are going ahead with design to demonstrate 25 NL/h Hydrogen
production capacity lab-scale unit. OEC started several sub-projects in
collaboration with some of the leading research institutions for research on the
initial proof of principle process development, which were to be followed up by
further development work to scale up the process.
128
In case of Cu-Cl cycle, the originally proposed five step cycle by
Argonne National Laboratories, USA has been modified and established.
Several novel designs especially in electrochemical section were made to
improve the system. The energy calculations showed that there is no
additional energy requirement in the modified cycle as compared to originally
reported ANL cycle and also reconfirmed that it is a non-catalytic process.
Efforts made to cross-confirm the data generated in electrochemical cell
parameters generated in the studies at ICT, Mumbai confirmed further that the
data is in the range reported in a parallel project study undertaken at CECRI,
Karaikudi.
Based on proof of concept studies, a conceptual closed-loop Cu-Cl
process for hydrogen generation@ 25L/h was developed to design and
fabricate a metallic lab-scale engineering process facility with indigenous
sources. A model metallic reactor fabricated initially helped freezing the
design and fabrication of hydrogen generation, CuCl2 hydrolysis,
decomposition and oxygen generation reactors. This approach has resulted in
considerable time and cost saving in the project besides instilling confidence
in indigenous capability development. A spray drier system was designed and
fabricated for drying CuCl2 to produce very fine and pure CuCl2 powder. The
electrochemical set up required in the integrated closed-loop operation was
developed using the data generated through series of electrochemical cells of
varying capacities viz., 2A, 5A, 12A finally leading to design/fabrication of 60
A stack with improved designs and indigenous fabrications using
commercially available materials viz., electrodes, membranes, cell materials
etc. During the studies, a novel method was developed for complete
conversion of CuCl after electrolysis reaction based on which a suitable
process gadget was designed to enable trouble free closed-loop operation of
the cycle.
In the integrated facility indigenously developed for closed-loop
operation all reactors viz., hydrogen, oxygen generation, CuCl2-hydrolysis and
decomposition along with electrochemical system were individually checked
for their performance and found to be working as per desired specifications.
Several facilities required for transfer of solids between individual units were
developed with a newly designed and fabricated flexible screw conveyor
along with provision for liquid transportation between various units across the
loop.
The engineering scale process plant, now installed at ICT, Mumbai is
proposed to be shifted to OEC project site in Panvel.
129
In the I-S cycle, electrochemical Bunsen reaction and electro dialysis
technique for HI enrichment were established at lab-scale with minimum
cross-contamination levels across membrane and without any side reactions.
Model codes were developed in simulation work undertaken to address
scaling up and issues related to integration with the remaining sections of the
cycle. In H2SO4 decomposition section of this cycle, a cost-effective, high
performing and highly stable non-Pt-based catalyst system was developed
and tested in an in-house designed, fabricated pilot scale metallic reactor
system equivalent to 150 L/h of H2 generation. Performance of selected
catalyst system under lab stage was evaluated further in this reactor at
900±50°C and 10-15 bars and found to be highly satisfactory. Mechanistic
studies on catalytic decomposition of H2SO4were completed. In HI
decomposition section, a highly performing transition metal based catalyst
system was developed that yields conversion being close to equilibrium
values at 500-550°C. The catalysts were stable for over 100 hrs. Through a
short study techno-economic feasibility of open loop I-S cycle was also
evaluated.
The research work performed by OEC and the collaborating
institutions have thus been able to successfully establish the proof of concept
for developing both Cu-Cl and I-S cycles and has led to setting up metallic
closed loop lab scale engineering facility in Cu-Cl cycle. These
accomplishments are major steps in technology development for these two
processes and achieved for the first time in the country.
ONGC Energy Centre has been able to successfully develop the
indigenous process, several process equipment and trained manpower in the
country. The collaborative R&D on both cycles has resulted in
publications/presentations of 46 technical papers in national / international
conferences and Journals. The research work has also resulted in filing of 7
Indian patents. In addition, keeping in view the recent international
developments in research in Cu-Cl cycle, which is considered most potential
for scale up, OEC has filed 3 international patents related to Cu-Cl cycle in six
countries (UK, USA, Canada, Japan, Korea and China). In the last few
months USA and Japan have accepted our patent application on multi-step
Cu-Cl cycle and patent has been granted in these two countries.
Scheme of R&D activities related to I-S cycle at OEC, Mumbai is given
in Figure 6.24.
130
Figure 6.24 Scheme of R&D activities related to I-S cycle at OEC, Mumbai
6.3.3 Highlights of the R&D Work
The OEC had planned to implement the project work in two distinct
stages viz., establish the proof of concept, followed by the lab-scale
development in association with collaborative research group for the
selected process route and thereafter, setting up of the pilot plant at OEC
premises at appropriate time to transform the developed knowledge and
expertise to further scale up. In this context, a total of 16 collaborative sub-
projects and 1 in-house project were undertaken as per details given below:
8 sub-projects to establish proof of principle of both the Cu-Cl and I-S
cycles
131
3 sub-projects to establish alternate paths for these cycles
1 sub-project to establish closed-loop operation of Cu-Cl cycle
1 sub-project to establish techno-economic feasibility of open-loop
cycle
3 sub-projects to addresses various issues related to simulations /
modeling, scale up / bridging the gaps for achieving closed loop
operations
1 In-house sub-project on simulation of I-S and Cu-Cl Cycle
The details of various collaborative sub-projects / in-house projects
undertaken in line with the scope of the work are given in Table 6.1:
Table 6.1 List of Collaborative Sub- projects in I-S and Cu-Cl Cycles
1 Proof of Principle of Cu-Cl Cycle (3 Sub-projects)
Sl.
No
Title of the Project
Duration / Start
Date / End Date
Institute Amount
committed
(Rs Lakh)
Amount
Released
(Rs Lakh)
Status
1.1 Preliminary process
analysis for copper-
chlorine (Cu-Cl)
thermochemical
hydrogen
production process
42 months /
01.07.07 /
31.12.10
ICT,
Mumbai
80.40 80.40 Completed
1.2 Experimental data
collection on
oxidation of CuCl
and recovery of Cu
10 months /
28.04.08 / 28.02.09
CECRI,
Karaikudi
6.23 6.23 Completed
1.3 Studies on the
electrolysis of CuCl
& recovery of Cu –
Energy
Optimisation –
Phase II
9 months / 27.02.10
CECRI,
Karaikudi
10.70 10.70 Completed
132
/ 26.11.10
Sub Total-1 97.33 97.33
2 Proof of Principle of I-S Cycle (5 Sub-projects)
2.1 Studies on the
catalytic
decomposition of
Sulfuric acid in the
I-S process for
Hydrogen
production
57 months /
11.01.08 / 11.10.12
IIT-Delhi 107.74 107.74 Completed
2.2 Studies on Bunsen
reactor for
production of
sulfuric acid and HI
using
electrochemical
cell48 months /
21.01.08 / 21.01.12
IIT-Delhi 102.77 102.77
Completed
2.3 Concentration of
HIx Solution Using
Electroelectrodialys
is
48 months /
21.01.08 / 21.01.12
IIT-Delhi Completed
2.4 Catalytic
Decomposition of
Hydrogen Iodide
(HI) into I2 and H2
57 months /
29.09.08 / 30.06.13
IIT-Delhi 45.63 45.63 Completed
2.5 Development of
Hydrogen
Transport
Membrane
Reactors for
Hydrogen Iodide
decomposition
followed by
hydrogen removal
36 months /
29.09.08 / 28.09.11
IIT-Delhi 31.64 31.64 Completed
133
Sub Total -2 287.78 287.78
3 Simulation of I-S Cycle (1 Sub-project)
3.1 Simulation studies
on the sulphur-
iodine (I-S cycle)
closed loop
thermochemical
process for
production of
hydrogen using
suitable simulation
and application
software
24 Months /
15.12.09 /15.12.11
Dr.
Babasaheb
Ambedkar
Univ.Loner
e,
Maharashtr
a (BATU)
4.09 4.09 Completed
Sub Total -3 4.09 4.09
4 Design, Installation and Lab Scale Demonstration of Closed Loop
Operation (1 Sub-Project)
4.1 ICT – OEC Process
for Copper-Chlorine
(Cu-Cl) Thermo-
chemical Hydrogen
Production –
Phase-II
30 months /
23.02.12 / 22.08.14
ICT,
Mumbai
767.87 767.87 Completed
Sub Total -4 767.87 767.87
5 Additional Studies / Alternate paths in Cu-Cl Cycle and I-S Cycles
Cu-Cl Cycle (1 Sub-Project)
5.1
Electrolysis of CuCl
– HCl system for
the preparation of
CuCl2& H2 - A
Feasibility Study
23 months /
05.04.10 / 04.03.12
CECRI,
Karaikudi
25.91 25.91 Completed
Sub Total -5 25.91 25.91
I-S Cycle (2 Sub-Projects)
5.2 Experimental
Studies for
Reaction of Metals
with HI 1.5 months
ICT,
Mumbai
2.20 2.20 Completed
134
/ 10.01.11 /
23.02.11
5.3 Experimental
Studies for
Reaction of Metals
with Hydroid Acid
&Detailed Studies
on Decomposition
of Certain
Transition Metal
Iodides
5 months /
14.09.11 / 13.02.12
ICT,
Mumbai
9.85 9.85 Completed
Sub Total -6 12.05 12.05
Techno-economical Studies on Partially Open-loop I-S Cycle (1 Sub-
project)
5.4 Techno Economic
Feasibility of Open
Loop Thermo-
chemical S–I cycle
of H2S split for
Carbon-Free
Hydrogen
Production in
Petroleum Refinery
4 months / 10.01.12
/ 09.05.12
CSIR-IIP,
Dehradun
13.47 13.47 Completed
Sub Total -7 13.47 13.47
Additional studies to address scaling up issues in I-S Cycle (2 Sub-
projects)
5.5 Modeling of
Membrane
Electrolysis Cell for
Bunsen Reaction
and Electro-
Electrodialysis Unit
for concentration of
Hix Solution
9 Months / 08.02.13
/ 07.11.13
IIT, Delhi 10.86 7.61 Completed
135
5.6 Mechanistic
Studies on the
Catalytic
Decomposition of
Sulfuric Acid in the
I-S Cycle for
Hydrogen
Production
12 months /
25.02.13 /
24.02.14
IIT, Delhi 17.48 11.19 Completed
Sub Total -8 28.34 18.80
Grand Total (Sub
Total 1-8)
1236.84 1236.84
6.0 Simulation Studies
on Thermochemical
Iodine-Sulfur&
Copper-Chlorine
Cycle for Hydrogen
Production
5 Years / May
2010 – Sept. 2015)
OEC
(In-house)
- - Completed
The linkage between various sub-projects is shown in Figure 6.25.
136
Figure 6.25 Linkage between various sub-projects
6.3.4 Highlights of the R&D Work
(i) Cu-Cl Cycle
The proof of principle experiments for all reactions of Cu-Cl cycle have
been successfully completed, using a combination of thermo-chemical
and electrochemical routes. This has resulted in development of a ICT-
OEC modified and patented Cu-Cl cycle.
In modified cycle; hydrolysis step was suitably modified to overcome
problems faced in formation and characterization of copper
oxychloride.
Detailed thermo-chemical calculations of the modified route indicated
that there is no excess heat demand in the modified route.
Analytical test methods and procedures to facilitate trouble free
operations during closed-loop operations have been standardized
In the electrochemical reaction, based on a novel cell design 2A cell
has been fabricated. It resulted in low cell voltage of 0.7 ± 0.1V along
137
with >90% current efficiency, 5-10μ particle size of copper generated in
the process under operating conditions that could be directly used as
feed / reactant in the Cu-HCl-Hydrogen generation reaction.
Kinetic studies for all reaction steps of the Cu-Cl cycle have been
performed and from the activation energy value it has been confirmed
that this is a non-catalytic reaction process.
Based on the experimental data generated in the proof of principle
experiments, a basic flow sheet has been initially developed for the
closed-loop experiment to generate hydrogen @ 2.73 liters per hour
(lph), subsequently revised to 5 L/h and finally to @ 25 L/h to align
with market supply of various process gadgets.
Detailed studies on flow simulations, cold flow experiments etc., have
been performed to finalize the reactor configuration.
A 5 Ampere electrochemical cell has been fabricated. The
performance of the cell showed that cathodic current density of
133mA/cm2 at a cell voltage of 0.7 ± 0.1 V.
Further scale up to a 12A electrochemical system was done with
improved design. A cathodic current density of 187 mA/cm2 at 0.7 ±
0.1V could be achieved.
Aerial oxidation of CuCl solutions has been found to be a major issue in
electrochemical step. A novel method has been developed for
complete conversion of CuCl after electrolysis reaction. Accordingly a
suitable process gadget has been designed and fabricated for onsite
application during closed-loop operation.
Based on the outcome of electrochemical studies, a 60A stack has
been developed to integrate with thermal reactors.
Initially a representative metallic model reactor system for hydrogen
generation @ 25 L/h has been designed and fabricated to study all
thermal reactions based on which design /fabrication of all the other
reactors viz., hydrolysis, decomposition and oxygen generation
reactors has been taken up. This approach has helped in reducing the
cost and meeting the project time line.
Hydrogen generation @ 27 L/h in the hydrogen generation reactor has
been achieved under specified operating conditions.
Hydrolysis reactor has been operated at 450°C and the reactor is
behaving ideally. When the oxygen generation reactor was run at
500°C; the experimental data indicated oxygen production @ 13.7 L/h.
CuCl2 decomposition reactor has yielded fine CuO powder and Cl2 gas
at 475oC.
138
Experimental runs on commissioned spray drier system have been
performed for drying CuCl2 at 140°C and the units have delivered
desired results. Data generated on the dryer unit have resulted in
encouraging results in which very fine and pure CuCl2 powder has
been obtained as confirmed by UV-Visible spectroscopy, iodometric
and titrimetric methods.
Simulations / Modeling studies in Cu-Cl cycle have been performed on
Aspen Plus simulator. Flow sheets for individual sections/ process
leading to integrated system / process have been developed. Energy
balance and mass balance has been calculated and compared with
theoretical values.
Proof of principle of alternate electrochemical reaction pathway has
been established at CECRI, Karaikudi. The studies have shown that
100% efficiency at low cell voltage (0.8V) and 250A/m2 current density
at 80°C under ambient pressure conditions could be achieved. Based
on lab studies, a 25A scale electrochemical cell has been designed to
work under specified operating conditions. The study has enabled
further modification in Cu-Cl cycle in reducing number of steps/
processes.
Solid handling problems in various sections for transfer of solid copper
and copper oxide between individual units have been achieved with a
newly fabricated flexible screw conveyor based on a novel ICT- design.
Provision for liquid transportation between various units across the
loop. Facility for Integration of various individual reactors leading to
form a closed-loop has been completed.
The details the reactions in ICT-OEC route of Cu-Cl cycle is given in
Table 6.2:
Table 6.2: The ICT-OEC route of Cu-Cl cycle
S. No. Reactions ICT-OEC route : Cu-Cl Cycle
1 Hydrogen Generation 2Cu(s) + 2HCl(g) → 2CuCl(l) + H2(g)
2 Electrochemical 4CuCl(l) → 2CuCl2(aq) + 2Cu(s)
3 Drying 2CuCl2(aq) → 2CuCl2(s)
4 Hydrolysis CuCl2(s)+H2O(g) → CuO(s)+ 2HCl(g)
5 Decomposition CuCl2(s) → CuCl(l)+½ Cl2(g)
6 Oxygen Generation CuO(s)+½ Cl2(g) → CuCl(l) +½ O2(g)
139
(ii) I-S Cycle
Proof of concept of complete cycle has been established using a
combination of electrochemical and thermo-chemical reactions.
Bunsen reaction has been successfully carried out at lab-scale using a
two-compartment membrane electrolysis cell consisting of graphite
electrodes and Nafion-117 membrane.
Excess iodine used could be reduced by 75% compared to direct
contact mode. The current efficiency close to 100% has been achieved
and absence of side-reactions has been confirmed
Cross-contamination has been found to be much lower than the direct
contact mode; loss of sulfate ions to HIx section (~12%) has been
noticed due to limitation on membranes.
Electro-Electro Dialysis (EED) technique has been established and
demonstrated in lab-scale to concentrate HIx solution beyond its
azeotropic concentration.
Only Nafion membranes have been found useful In electrochemical
work
Model codes for simulation work on electrochemical Bunsen and EED
sections for I-S cycle has been successfully developed to address
scale-up issues and integration with the remaining sections of the
cycle.
In H2SO4 decomposition study, a lab-scale model quartz reactor
system has been designed and assembled to screen various catalysts.
Several transition metal/metal oxide based catalysts viz., Fe2O3/Al2O3,
Fe2O3/ZrO2, CoO/Al2O3, CuO/ZrO2, Fe2O3, Cr2O3, CuFe2O4, ZnCr2O4,
FeCr2O4, NiCr2O4, CuxCr3-xO4 etc. were screened and relative
performance of some of these catalysts were determined.
Detailed kinetic and thermodynamic studies have been performed on
promising catalyst systems. Based on the studies, a cost-effective, high
performing and highly stable non-Pt-based catalyst system for catalytic
decomposition of H2SO4 has been developed.
For the decomposition of H2SO4, High Temperature-High Pressure
(HTHP) bayonet type metallic reactor for pilot scale operation
equivalent to 150 mph in terms of H2 generation was successfully
designed, fabricated & commissioned at IIT-Delhi using in-house
expertise and indigenous resources.
The proven catalyst system under lab-stage evaluation has been
further evaluated under high pressure (10-15 bars) - high temperature
(900±50°C) experimental conditions for 24hrs. Results of this study
140
have indicated encouraging trend with the conversions in the order of
~90%.
The developed catalyst has been found to be stable for longer
durations under the actual operating conditions. It is relatively cost-
effective and superior to the available products reported. Data
generated for high pressure high temperature (HP-HT) operation is
suitable for onsite application and integration in closed loop operation.
Mechanistic studies on catalytic decomposition of H2SO4 have been
completed to address scaling up issues and integrate this step with
remaining sections of the cycle.
A lab-scale model quartz reactor system has been designed and
assembled to screen various catalysts under operating conditions of HI
decomposition.
Several transition metal (Fe, Co, Ni) based catalysts and mixed metal
catalysts like Pt-Ni combinations have been synthesized and screened
over various catalyst beds viz., Alumina, Vanadia, Molybdina, Zirconia,
Activated Carbon, and SiC in the temperature range 400-550°C.
The generated data have indicated that nickel based catalysts worked
better with the conversion being close to equilibrium values (~22%) at
500-550°C.The catalyst deactivation studies performed over 100 hrs
also indicate a marginal decrease of nickel based system activity to
~20% at the end of the test.
Studies on alternate pathways in I-S cycle for HI decomposition
involving Metal – HI reaction has also been established to explore the
possibility of ease of operation by avoiding less energy efficient
distillation processes.
Techno economic feasibility of open loop thermo-chemical I-S cycle
has been successfully evaluated.
Simulation / modeling studies of I-S open/closed-loop cycle and
alternate routes have been successfully carried out using Aspen
simulator. Individual flow-sheets have been developed leading to
Integration of different sections with one another. Energy requirement
based on theoretical basis and efficiency calculations has been
performed.
Cu-Cl Cycle, I-S Cycle and I-S Cycle Open Loop for Hydrogen
Generation are compared in Table 6.3.
141
Table 6.3. Comparison of Cu-Cl Cycle, I-S Cycle and I-S Cycle Open Loop
for Hydrogen Generation
Sl.
No.
Attributes Cu-Cl Cycle I-S Cycle I-S Cycle
Open Loop
1 No. of Steps 6 Step Process
(Combination of
Electrochemical &
Thermochemical
Reactions)
3 Step Process
(Combination of
Electrochemical
&
Thermochemical
Reactions)
2 Step Process
(Combination of
Classical
Bunsen & Hi
Decomposition
of HI with
Reactive
Distillation step)
2 Establishment
of Proof of
Concept
Proof of concept
for all 6 steps
have been
established (OEC
and Collaborators)
Proof of concept
for all 3 steps
have been
established
(OEC and
Collaborators)
Collaborative
Work is in
Progress
3 Maximum
Temperature
Encountered
550°C
(O2 Generation)
900°C
(H2SO4 Section)
500°C
(Oxidation of
H2S)
4 Total Energy
Requirement
668 kJ/molH2 675 kJ/molH2 562 kJ/mol
5 MoC Relatively Lower
Temperature (Max
5500 C)
Higher
Temperature
(Max 9000 C)
Relatively Lower
Temperature
(Max 5000 C)
6 Catalyst Not catalytic
process
Catalysts
required for both
H2SO4 and HI
Decomposition
Catalysts
required for HI
Decomposition
7 Separation Solid – Liquid
Liquid – Liquid
Gases Separation
Liquid – Liquid
Separation of
complex
azeotrope
Separation by
Reactive
distillation in HI
decomposition
step
8 Membranes Imported
(Required in
electrochemical
step)
Imported
(Required for
EBR and EED
steps)
Not Required
(when Classical
Bunsen
Reaction is
followed)
9 Electrodes Required Required Not Required
142
(when Classical
Bunsen
Reaction is
followed)
10 Process
Efficiency
5 Step = 52.57%
4 steps
Nuclear Energy:
Generation IV
Supercritical
Water Cooled
Reactor (SCWR)
= 51%
Solar Energy:
Using molten salt
= 70%
3 Step = 40%
Using Reactive
distillation = 51%
(GA)
EBR & EED
(Ideal case) =
46.5%
51%
11 By-products /
Wastes
No waste as all
products are
recycled
No waste as all
products are
recycled
H2SO4 which
can be sold for
industrial use
7. Indigenous Equipment Development
Hydrogen Generation Reactor System is shown in Figure 6.26.
Figure 6.26: Hydrogen Generation Reactor System
143
12A Electrochemical Cell with perforated Pt plate as anode is shown in
Figure 6.27.
Figure 6.27: 12A Electrochemical Cell with perforated Pt plate as anode
Spray Dryer System is shown in Figure 6.28.
144
Figure 6.28 Spray Dryer System
CuCl2 Decomposition Reactor is shown in Figure 6.29 and Hydrolysis
Reactor is shown in Figure 6.30.
Drying
Chamber
(Borosilicate
glass)
Cyclones
(Borosilicate
glass)
Scrubber
(SS 316)
Control
Panel
Pump
Spray Nozzle:
Hastelloy C
Blower
145
Figure 6.29: CuCl2 Decomposition Reactor
Figure 6.30: Hydrolysis Reactor
Oxygen Generation Reactor is shown in Figure 6.31.
146
Figure 6.31: Oxygen Generation Reactor
Cu-Cl closed loop facilty is shown in Figure 6.32.
Figure 6.32:. Cu-Cl closed loop facilty
High Temperature-High Pressure Reactor for H2SO4 Decomposition is
shown in Figure 6.33.
147
Figure 6.33: High Temperature-High Pressure Reactor for H2SO4
Decomposition
H2SO4 pilot plant facility is shown in Figure 6.34.
Figure 6.34: H2SO4pilot plant facility
151
7.0 Hydrogen Production by Photo-electrochemical Water
Splitting
7.1 Introduction
The ever increasing energy demands and rapid consumption of fossil
fuels has triggered urgent need of sustainable and renewable sources of
energy. A lot of research and its commercialization have already been done in
the areas of solar photovoltaic, however, it requires storage of energy due to
its limited operation in day-time only. Hydrogen is one of the most promising
fuels due to its highest energy density (120 MJ/Kg). Environment and energy
crisis issues can be addressed if Hydrogen can be produced in a clean and
efficient manner. Steam methane reforming is most commonly used for
Hydrogen production in industries. Source for methane reforming is a fossil
fuel and moreover CO2 gas is emitted as shown in reaction 1 & 2.
CH4 + H2O → CO + 3H2 ------- (1)
CO + H2O → CO2 + H2 -------- (2)
Renewable production of Hydrogen through solar energy is essential
considering environmental issues and can also cater to the energy needs.
There are several ways of Hydrogen production through solar energy.
However water splitting is considered as the “Holy Grail” of sustainable
hydrogen economy. Water splitting phenomenon was first observed by
Researchers in Kanagawa University, Yokohamaduring1972 where TiO2
electrode was irradiated with UV light and Hydrogen was produced by
reduction reaction at cathode and oxygen is produced at anode by oxidation
reaction.
University of Notre Dame, Notre Dame, Indiana worked on
photocatalytic water splitting. Photocatalytic water splitting consists of a
powder catalyst dispersed in water or in some suitable solution. Catalyst used
in this process needs to be photoactive and should be capable of generating
necessary charge particles to activate redox reactions. Minimum bandgap
required to split water can be calculated from the relation in between Gibbs
free energy and potential as given below:
ΔG =-nFE
Where ΔG is the change in Gibbs free energy, n is number of electrons
transferred in chemical reaction, F is faraday constant and E is the bandgap.
For water splitting, ΔG = 237KJ/mol, n=2 and F=96500 C/mol. Therefore “E =
1.23V”, is the minimum potential and hence minimum bandgap of 1.23eV is
required to split water. Thermodynamic bandgap requirement for water
splitting
152
Figure 1: Thermodynamic bandgap requirement for water splitting.
Solar hydrogen production from direct photo electrochemical (PEC)
water splitting is the ultimate goal for a sustainable, renewable and clean
hydrogen economy. In PECwater splitting, hydrogen is produced from water
using sunlight and specialized semiconductors called photo electrochemical
materials, which use light energy to directly dissociate water molecules into
hydrogen and oxygen. This is a long-term technology pathway, with the
potential for low or no greenhouse gas emissions. While there are numerous
studies on solving the two main photo-electrode (PE) material issues i.e.
efficiency and stability, there is no standard photocell or photoreactor used in
the study. The main requirement for the photocell or photo-reactor is to allow
maximum light to reach the PE.
The PEC water splitting process uses semiconductor materials to
convert solar energy directly to chemical energy in the form of hydrogen. The
semiconductor materials used in the PEC process are similar to those used in
photovoltaic solar electricity generation, but for PEC applications the
semiconductor is immersed in a water-based electrolyte, where sunlight
energizes the water-splitting process. PEC reactors can be constructed in
panel form (similar to photovoltaic panels) as electrode systems or as slurry-
based particle systems, each approach with its own advantages and
challenges. To date, panel systems have been the most widely studied, owing
to the similarities with established photovoltaic panel technologies.
Photo-electrochemical process consists of an electrode of
semiconductor material, which is photoactive and is capable of generating
electron hole pair when light (photons) is incident on its surface. One of the
advantages of photo-electrochemical cells is reduction and oxidation reaction
happens at different electrodes eliminating the need for separation of gases.
153
However, chemical stability of materials inside electrolyte solution or water is
a challenging issue.
Schematic diagram of a typical photo-electrochemical cell consisting of
n-type semiconductor photoanode, reference (SCE) and metal cathode for
water splitting is shown in Figure 2.
US DoE has set following benchmarks for commercialization of PEC
water splitting technology for hydrogen production.
Criteria 1: 10% Solar to Hydrogen conversion efficiency.
Criteria 2: Stability against Chemical, electrochemical and photo-
corrosion. Working time of at least 1000-hour without significant
degradation.
Criteria 3: Cost of hydrogen production should be economical.
Figure 2: Schematic diagram of a typical photo-electrochemical cell
consisting of n-type semiconductor photoanode, reference
(SCE) and metal cathode for water splitting.
7.2 Process of water splitting
The crux of water splitting process lies in the redox reaction with the
participation of generated charge carriers through solar radiation at catalyst
surface (or active sites). Materials used for catalysts or electrode preparation
are semiconductor in nature. Therefore, they have a defined band gap which
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is a result of the separation of conduction and valence band. Moreover band
edges also play an important role in the selection of the material. Conduction
band edge should be more negative than the reduction potential of the
hydrogen and valence band edge should be more positive than the oxidation
potential of oxygen for water splitting. When light of a particular wavelength is
incident on the catalyst, electron-hole pair is generated only if the photon
energy is more than the band gap of the material. Electron is then migrated to
the conduction band leaving a hole in the valence band.
Next step is separation of charge carriers and their movement to the
surface of the catalyst. For an efficient process, mean life time of the
generated carriers should be high or recombination rate should be low.
Recombination rate in a semiconductor material is affected largely by crystal
defects. Crystal defects acts as electron traps which neutralizes holes. To
inhibit recombination of electron-hole pair, a co-catalyst is generally used.
Generally used co-catalysts are platinum, nickel, ruthenium, rhodium,
palladium, iridium and rhodium. Another requirement of co-catalysts is to
impede the back reaction in between hydrogen and oxygen. However, in
photo-electrochemical, charges are separated by putting a separate electrode
of aforementioned noble metals.
A research group in Kyoto University, Kyoto, Japan worked on the non-
equilibrium interfacial phenomena occurring under microgravity in water
electrolysis. Once separated electron and hole pair is available, redox
reaction can be conducted on the surface of catalyst/co-catalyst. Hydrogen
ion is reduced to hydrogen gas by the transfer of trapped electron and
hydroxyl ion is reduced to oxygen gas by neutralizing the hole in valence
band. Oxidation reaction in water splitting is a 4-electron transfer process and
therefore, valence band has to be deep enough for transfer of charges.
Reduction at cathode: 2 H+(aq) + 2e− → H2(g)
Oxidation at anode: 2 H2O(l) → O2(g) + 4 H+(aq) + 4e−
7.3 Evaluation Parameters
Evaluation of a water splitting system is done on the basis of amount of
gas (hydrogen and oxygen) evolved in due course of time. Amount of gas is
measured in moles and therefore unit for rate of evolution is mol per unit time
(for instance; µmol/hour). Parameter Quantum Yield can be used to compare
different photoactive material under similar operating conditions (Modern
Aspects of Electrochemistry, New York).
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Number of reacted electrons
Quantum Yield = x 100%
Number of absorbed photons
Actual quantum yield is usually more than the quantum yield mentioned
above. This difference can be computed if the incident light spectrum and
absorption spectrum of the material is known. Overall efficiency can be
computed on the basis of total input energy versus total output energy. In
case of solar hydrogen production, input energy is the incident Sun’s energy
and output energy is the energy content of evolved hydrogen gas.
Output energy of hydrogen
Solar to hydrogen efficiency = x 100%
Energy of incident solar light
(mol H2/s) x (237kJ/mol)
= x 100%
(Inc Power W/m2) X Area (m2)
In photo-electrochemical, another term specified as ‘applied bias
photon to current efficiency’ is more suitable as an external source is usually
required for transfer of charge particles from main electrode to counter
electrode.
Applied Bias solar to hydrogen efficiency
Current density (mA / cm2) x (1.23 – Vbias) (V)
= x 100%
Ptotal (mW/cm2) at AM 1.5G
7.4 National and International Status
Photo-electrochemical water splitting for hydrogen generation is based
on solar energy and water, both of which are renewable sources. Energy for
stationary and transportation applications can be retrieved from hydrogen with
low carbon foot print and climate impact. Ever since in the first report,
Researchers in Kanagawa University, Yokohamaduring1972 demonstrated
the feasibility of hydrogen generation via photo-electrochemical splitting of
water, lot of efforts have been made by different workers across the globe to
exploit this process for commercial production of hydrogen. Main focus of this
research has been to search for an ideal semiconductor that can be used as
efficient photo-electrode in this process. However, the long cherished goal of
reaching at least 10% conversion efficiency has so far remained unachieved.
Working at this efficiency, with photo-current generation at the rate 10-15 mA
156
cm-2, would imply that the cost of hydrogen production would be economical.
This would be a cost competitive against the existing costs of conventional
fuels and would make this process commercially viable. Another issue
important in the process is of semiconductor material durability in contact with
PEC cell electrolyte. It is desired that the material should remain stable at
least for 2000 working hours.
Researchers in Yerevan State University, Armeniain2005 has
concluded that among different semiconductors used for PEC water splitting,
the best efficiency is detected in metal oxide photo-electrodes, which were
partially reduced and contained an optimal concentration of impurities. In the
ongoing search for a material with above desired characteristics, in recent
years several new dimensions have been added (plate 1). Use of mixed
oxides, Combinatorial approach and designing of high throughout fast
screening procedures, adoption of density functional theory to screen the
materials, Use of phosphides, Selenides, Graphene and CNT based systems
and layered structure are some recent developments in this field of research.
Besides above mentioned work, research pertaining to geometry orientation
and shaping of nanomaterial (by orthogonalizing direction of light absorption,
charge collection, charge separation/ transportation), exploring bandgap and
band alignment as a function of composition, doping and morphology for
engineering structures, which have features favorable for water photolysis,
are also being explored.
Few of the promising material(s) system for application in PEC water
splitting are given in Plate 1.
The Institute of Minerals and Materials Technology (IMMT),
Bhubaneswar developed functional hybrid nano structures for photo
electrochemical water splitting. The different photo-catalytic materials
developed for hydrogen production through water splitting, which were
continuously operated for 6-7 hours. Among the developed materials like CdS
photo-electrodes and CdS nano-crystal powder photo-catalysts with yield of
800-1000 mg/batch, 0.28 wt% P3HT modified CdS with yield of 4087 µmol/h/g
and CdS-NaNbO3 core-shell nano-rods with yield of 11,901 µmol/h/g, the
CdS-NaNbO3 core-shell nano-rods was found to give maximum hydrogen
production.
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Plate 1: Few of the promising material(s) system for application in PEC
water splitting
7.5 Action Plan
Action plan consists of two main activities: (i) basic R & D towards the
identification, synthesis and laboratory-scale PEC measurements on
prospective materials/material systems; (ii) up-scaling of the
materials/systems found promising with respect to their solar-to-hydrogen
conversion efficiency and stability under longer illumination time. Research
will be conducted under following lines:
I. Laboratory-scale studies on prospective materials and their
performance evaluation
Core activity 1: Exploration on promising semiconductors/systems
Extensive R & D is required to be undertaken concerning the photo-
electrochemical measurements for hydrogen generation via photo-splitting of
water by employing the promising semiconductors. Thin films of the
semiconductors would be converted into electrode by adopting the standard
procedure and used in PEC water splitting studies. For converting films into
electrode, initially an electrical contact would be generated using silver paint
and copper wire. The Ohmic contact so prepared and all the sides of film
Properties required?
Band gap energy ≈ 2 eV
Strong optical absorption
Long life time of charge
carriers
Conduction and Valance
band edges to straddle water
redox potentials
High Stability in electrolytes
Non Toxic & Economical
PEC
Water
Splitting
Material
Issues
Strategies being
tried
Doping
Surface
Modifications
Layered
Structures
Dye
Sensitization
Swift Heavy
Ion irradiation
Mixed Oxides
Systems Investigated:
ResultHighlights
New concepts/ Emerging Trends ………..
Fe2O3-
Graphene
Nano-
composite
Bio-inspired Co-
catalyst CoPi on
the surface
CdSe QD electro-
deposited on α-Fe2O3
films
ZnO modified
with Cu ion
implantation
Nanocomposites Quantum
Dots
Bio inspired
catalysts
Metal Ion
Implantatio
n
158
(except the front side) would be sealed with the coating of an opaque and
non-conducting epoxy. So prepared thin film working electrodes would be
used as photo-sensitive working electrode, in conjunction with platinum
counter electrode and saturated calomel electrode (SCE, as reference
electrode), at varying electrolyte conditions. Nature and concentration of the
electrolyte and its pH would also be varied in order to optimize the conditions
of hydrogen evolution. Current (I) – Voltage (V) characteristics of PEC cell
would be studied, both under darkness and illumination. By observing the I-V
plots, onset voltage for photo-current would be determined, and based on
these measurements the performance of PEC cell would be evaluated. As
mentioned above this constitutes the core activity in the proposal. The
sustained R & D effort in this direction by the investigators for the past 15
years has led to few of the promising material-options in this regard that need
to be tested at the next level, which involves their integration with pilot-scale
hydrogen generation reactor and the performance evaluation of such reactors
both under controlled conditions as well under real-time solar illumination.
However, as is evident from the literature survey and the recent emerging
trends in this vital area of research, the material issue is yet not finally settled.
As a matter of fact, each of the existing material-options has its own
drawbacks and the researchers are trying to crack those issues.
Core Activity 2: Scale-up studies and related issues
Moving towards solar energy fed pilot-scale hydrogen generation
reactors such that it can perform efficiently under field conditions, this core
activity has been chalked out. The above mentioned two semiconductor
systems would be investigated for this purpose in the beginning. However,
any new material/ system that promises to be even better as observed under
core activity 1, would also be incorporated in the work-plan under this activity.
Key work elements involved, especially pertaining to the synthesis of large
area electrodes would be as:
Suitable synthesis methods as described in objectives to be used for
preparation of electrodes.
First-level up-scaling studies with existing facilities at Dyalbagh
Educational Institute, Agra. Electrodes of at least 3 different
dimensions to be fabricated and tested under controlled laboratory
conditions.
Scaling of electrodes from 1cm2 to 150 cm2 active area. Feasibility of
maximum area of electrode (150 cm2) to be determined by conducting
experiments. These experiments will be conducted with state of the art
instruments at IOC-R&D which is a part of the procurement activity of
the present project plan. Two routes of large area electrodes shall be
159
explored – one having single large area electrode and the other –
several small electrodes connected in suitable configuration so as to
result into large area exposure
Empirical modeling of performance versus increase in the area of
electrodes. Determining maximum feasible size of the electrode that
can be incorporated in the reactor.
Study on scaling of counter electrode with respect to increase in the
area of working electrode.
Optimization of interconnection design for working and counter
electrodes.
II. Studies on reactor design and fabrication.
Core Activity 3: Designing the Reactor
Designing reactor: Theoretical modeling and testing
Study of different losses associated with electrode and electrolyte
interfaces.
Qualitative and quantitative study of electrolyte and electrode
resistance components.
Study on feasibility of packaging electrodes in parallel connections,
their associated losses and optimum size possible for a reactor.
Core Activity 4: Fabrication of Reactor
Actual design of the reactor will be taken up after study on electrodes.
Key step of the work planned are mentioned below:
A lab scale reactor will be fabricated to support scale-up activities for
performance evaluation of electrodes of different sizes. Basic design
would be similar to that of a twin compartment reactor. Separate
compartments will be available for working and counter electrode. This
will eliminate need for the separation of evolved gases (hydrogen and
oxygen). Moreover, reactor will be air tight and provision will be made
to sample evolved gases for analysis. Furthermore, an additional
provision will be provided to input feed without opening the reactor or
without interrupting the ongoing process.
An electronics circuit will be designed to supply constant external bias
to the electrodes. Initially battery will be used for supply and
subsequently efforts will be laid to try to use photovoltaic panel for
supplying external bias to electrodes.
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A bigger bench scale reactor will also be fabricated as a part of the
project. This bench scale reactor will exhibit a maximum active area of
~ 900cm2. All the challenges faced in the lab scale reactor will be
addressed in the design of this reactor. Bench scale reactor will also
have the provision of two compartments wherein both the hydrogen
and oxygen gases can be separated. Benchmark data will be
generated by controlled indoor testing with large area illumination
continuous light solar simulator.
Core Activity 5: Fabrication of Reactor
Performance evaluation
Under controlled laboratory conditions
It is proposed to set up a continuous solar simulator in laboratory which
can illuminate electrodes up to a maximum area of~ 900 cm2.
Under real-time solar illumination outdoor field conditions
Real-time testing will be taken up after laboratory testing. Performance
will be evaluated with respect to the real time data obtained from a
weather station already in place at IOC-R&D.
7.6 Summary and Recommendations
Among the various material groups for the photo-electrodes,
semiconductor metal oxides are relatively inexpensive and have a better
photo-chemical stability, many metal oxides have been extensively studied
and significant progress has been achieved in past two decades both
nationally and internationally.
Among the metal oxides; Iron, copper, bismuth vanadium and zinc
have been researched globally for their performance in photo water splitting.
Promising results have been achieved with aforementioned metal oxides;
nano-wire arrays of hematite has shown a promising current density of 3.44
mA/cm2, oxides of Bismuth has been reported with current density up to 2.3
mA/cm2, current density of the order of 2.34 mA/cm2 for Cu2O sample (1 at. %
Ag) under visible light illumination at 0.8 V/SCE has been reported.
While the search for new and more efficient semiconductor
materials/systems for above application would continue, studies are also
needed on up scaling the device by initiating R & D efforts in this direction.
Metal oxides, viz. Fe2O3, TiO2, ZnO, CuO, Cu2O, SrTiO3, BaTiO3 etc are
important class of semiconductors, viewed largely as prospective material
systems for PEC applications. Further, in order to overcome certain limitations
associated with these metal oxides, these were subjected to various
161
modifications viz. doping, swift heavy ion irradiation, dye sensitization etc.,
yielding varied improvements on their performances. Nanocomposites, bio-
inspired systems, quantum dots, and ion implantation are amongst the
different newly emerged concepts that have drawn the attention of
researchers and are being investigated with lot of hope and expectations.
Research on scale-up and reactor is equally important as that of the
material research. Efficient and reliable materials need to be studied further
for scalability. Demonstration at lab scale and pilot scale can be significant
towards realizing the ultimate potential of the technology.
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8.0 Hydrogen Production by Other Technologies
8.1 Hydrogen Production by non-thermal plasma assisted direct
decomposition of hydrogen sulphide
8.1.1 Hydrogen Sulfide is an inorganic compound that causes severe odor
problems. The emission of Hydrogen Sulfide from petroleum industry, coal
gasification and animal industry has to be regulated as the odor threshold for
Hydrogen Sulfide is 1 ppbv. Hydrogen sulphide occurs as a by-product in the
production of coke form sulfur- containing coal, the refining of Sulphur-
containing crude oils, the production of carbon disulphide, the manufacturer of
viscose rayon, and in the Kraft process for producing wood pulp. Hydrogen
sulphide is the most dangerous of the gases produced by the anaerobic
decomposition of manure. Large amounts of Hydrogen Sulfide are produced
worldwide, mostly from natural gas production and oil refining. Yearly
tonnages of H2S can be deprived from sulfur production, 14.4 million tons
from sour gas and 9.6 from refineries, worldwide. This sour gas potentially
contained about 342, 000 tons (3.8 billion cubic meters) of hydrogen. Oil
refineries and upgraders use hydrogen as well as make H2S, and for this
reason constitute a logical location for a H2S dissociation plant.
Conventional methods to controls hydrogen Sulfide include absorption
(wet scrubbing), absorption, incineration (thermal and/or catalytic), and bio-
filtration. The widely employed Claus method is based on partial combustion
of hydrogen sulfide into sulfur dioxide followed by the catalytic conversion of
H2S + SO2 mixture into elemental sulfur and water. Earlier methods were
focused on recovery of elemental sulfur, however the desired reaction would
be the production of hydrogen by direct oxidation of hydrogen Sulfide, which
is endothermic and thermodynamically unfavorable.
An alternative approach is to use Non-thermal Plasma (NTP)
generated at atmospheric pressure and room temperature. NTP, the fourth
state of the matter consists of energetic electrons, radicals, atoms and
molecules. At low consumption of energy, NTP produces highly energetic
electrons that initiate the chemical reaction leaving the background gas nearly
at room temperature. Recently dielectric barrier discharge (DBD) reactor with
catalytic sintered metal fibre (SMF) electrode has been tested for the
abatement of volatile organic compounds. It was demonstrated that the metal
oxide modified SMF electrodes, performance of the NTP technique could be
improved.
8.1.2 International Status
It is known since long that strong healing decomposes hydrogen
sulphide. Thermal decomposition has recently been implemented at the pilot
166
scale at a gas plant in Alberta. Conversions close to equilibrium have been
observed. An economic study showed that costs for thermal decomposition
would be close to those for conventional processes. Improvements in
separation technologies are needed to enable commercial implementation of
thermal decomposition.
As of today there is no commercial technology for the production of
hydrogen from hydrogen sulphide. The conventional method for hydrogen
sulphide removal is the Claus process, which produces sulfur and water
instead of hydrogen and sulfur that are beneficial. Besides sulfur recovery
limitations, major disadvantage of the Claus process is that the valuable
product hydrogen is converted into water. Moreover, the cost of tail gases
cleanup from Claus plant can exceed the value of sulfur recovered if the
environmental regulations become more stringent. Regarding the catalytic
process, only limited information has been reported, where none of the
catalysts was promising. One of the reasons could be the severe reaction
conditions like high operation temperature (>2000K). Among the several
techniques tested for the production of hydrogen, Idemitsu Kosan Hybrid
(IKC) electrolysis process has been considered as feasible. It is based on
absorption of hydrogen sulphide by Ferric chloride aqueous solution followed
by electrolysis to generate hydrogen and sulfur. IKC process consumes 3.6
kWh/Nm3 hydrogen, whereas steam reforming of methane, the traditional
approach for hydrogen production demands still higher energy of 4.3
kWh/Nm3hydrogen. Like-wise, 40% conversion of hydrogen sulphide by
thermal decomposition can be achieved at temperature ~ 1500K, which is
equivalent to 2.76kWh/Nm3 of hydrogen. At this temperature considerable
amount of by-products like SH were produced. Formation of pure Sulphur and
hydrogen was observed only above 2273K. The practical limitation of this
technique is the operating conditions and separation of products at this
temperature. The main advantage of carrying out hydrogen sulphide
decomposition in the novel DBD reactor is the production of hydrogen in an
economically feasible manner under ambient conditions.
8.1.3 National Status
Most of the research in this area has been focused on
catalytic/photocatalytic decomposition of hydrogen sulphide. However, in both
the cases, catalyst deactivation due to the deposition of sulphur decreases
the efficiency. But, photocatalytic decomposition of hydrogen sulphide to
hydrogen and sulphide offers some promise. Hydrogen sulphide under visible
light to generate hydrogen is an attractive route of solar energy conversion,
because hydrogen is 100% environmentally clean chemical fuel in its cycles
of generation and utilization. Although hydrogen generation from water in
visible light represents a potentially viable route of solar energy conversion, till
date only marginal conversion efficiency has been achieved (5.1% quantum
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yield with sacrificial agents and 2.5 % from pure water. Obviously, the
difficulty in achieving high efficiency is attributed to the involvement of many
high energetic reactive species in the thermodynamically uphill water spilling
reaction.
The Indian Institute of Technology Hyderabad developed the process
of non-thermal plasma assisted direct decomposition of hydrogen sulphide
into hydrogen and sulphur. This process is feasible and advantageous over
Claus process where sulphur alone is recovered from hydrogen sulphide. It is
possible to achieve hydrogen production at about 160 kJ/mole that
corresponds to energy conversion of 2 kWh/Nm3 of hydrogen, which is less
than the energy required for hydrogen production from SMR (about 346
kJ/mole of hydrogen). A packed bed configuration with glass tubes reactor
showed best performance of the reactor which was attributed to the change in
discharge properties. MoOx supported on Al2O3 catalysts showed better
conversion compared to CoOx and NiO due to deactivation of CoOx and NiO
quickly due to sulphur poisoning. Hydrogen production of 0.5 litre/minute was
achieved in the laboratory.
The NTP technology is environmentally friendly and operationally
simple. Another advantage of the suggested process is that the hydrogen
produced is free from impurities, hence secondary purification can be
avoided. The reaction conditions can be still improved to decrease the energy
consumption.
8.2 Hydrogen Production by Photo-splitting of Hydrogen Sulphide
8.2.1 Hydrogen sulphide is a toxic gas occurs widely in natural gas fields and
is produced in large quantities as a byproduct in the coal and petroleum
industry. Currently this toxic gas is converted into sulphur using Claus’s
process or released into the atmosphere. Photo-splitting of hydrogen sulphide
into hydrogen can be an attractive option by conventional the Claus’s process.
Hydrogen sulphide Cleavage process might be used in industrial procedures
where hydrogen sulphide or sulphides are formed as a waste whose rapid
removal and conversion into hydrogen is desired. Currently, for this
application oxide catalysts have been studied but due to certain limitations,
researchers are trying to develop catalyst which can absorb maximum part of
solar radiation and are active under natural solar light. Extensive work has
been carried out for the development of ultraviolet driven photocatalyst for
water and hydrogen sulphide splitting. However, there is a demand for highly
efficient photocatalyst for production of hydrogen under visible light irradiation.
Stability and efficiency of these catalysts still low and need improvement.
There is need to develop prototype photo reactor for hydrogen production
from hydrogen sulphide using solar energy and field trials using gas emitted at
refinery sites using a batch type photoreactor.
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8.2.2 International Status
Semiconductors mediated heterogeneous photocatalysis has become
an attractive technology for environmental pollution remedy, particularly due
to its potential to degrade a wide range of inorganic and organic compounds
in both waste gases and water. The initial reaction step consists of of
electron-hole pair’s production by irradiating the semiconductor with light
having an energy content equal to or higher than the band-gap of
semiconductor. After separation of photogenerated electrons and holes due to
trapping by species adsorbed on the semiconductor, redox reactions occur
between trapped electrons and holes and adsorbate. Most of the
semiconductor photocatalysts investigated are metal oxides (e.g. TiO2, ZnO,
SnO2, WO3) and chalcogenides (e.g. CdS, ZnS, CdSe, ZnSe, CdTe) [1-5]. As
hydrogen-based power and transportation technologies develop the need for
an effective hydrogen source to power fuel cells in the hydrogen economy.
Hydrogen from photo-electrochemical cells is believed to offer the prospect of
such a source. Photocatalytic splitting of water using n-type TiO2 under UV
illumination was first reported over 30 years ago by Researchers in Kanagawa
University, Yokohama. Since then a number of photocatalytic compounds
have been investigated with the aim of improving catalyst activity and stability
in the irradiated aqueous environment. In 2001 Zou et al. first demonstrated
the direct splitting of water by visible light over an In1.xNixTaO4 photocatalyst.
As energy conversion devices, water-splitting photo-electrochemical cells
convert photon energy to the Gibbs free energy of hydrogen and Oxygen via
excited electron states in the photocatalyst. These excited electron states
result from the promotion of valance band electron to a level above the
conduction band edge on the absorption of an incident photon. In practice,
any energy in the excess of the bandgap energy will be dissipated as heat
since electrons promoted to higher states readily thermalise to the conduction
band edge. Internationally, the research on hydrogen generation from
hydrogen sulfide and water is still at academic level. No commercial process
has been developed yet. Many groups in Japan, Korea, U.S, Europe is
working on development of active photocatalysts for hydrogen generation
under visible light irradiation. University of Tokyo, Japan has done extensive
work on photocatalysts for water splitting and recently has reported many UV
and visible light catalysts.
Considering the depletion of other energy sources, it is quite essential
to develop new sources of energy. Development of active photocatalyst for
photo-hydrogen generation will be advantageous for future energy demand.
169
8.2.3 National Status
In India, large number of groups is working on photocatalytic
decomposition of organic waste and toxic materials. Very few groups are
working on photocatalytic splitting of water and hydrogen and hydrogen
sulphide into hydrogen under visible light. Few research group in BARC are
working on photocatalytic degradation of nuclear waste as well as water
purification. Some research teams in IISc, Bangalore are working on TiO2
based photocatalysts for organic waste degradation. In addition to this, some
researchers in IIT, Mumbai and Madras, CECRI, Karaikudi, IICT, Hyderabad
and few universities in India are working on photodecomposition of organic
pollutants. But the photo catalysis work has not crossed the development of
other possible new active photocatalyst other than TiO2andCdS. The current
trend in the country is only the degradation of waste or organic using TiO2/Cds
photocatalyst. Only C-MET Pune is working on hydrogen generation by
photocatalytic decomposition of toxic hydrogen sulphide. In India, the
development of active photocatalyst for pure hydrogen generation by water
and hydrogen sulphide splitting is still at academic level. It is essential to
develop catalysts useful under solar light for the decomposition of
water/hydrogen sulphide into hydrogen. The hydrogen sulphide from the
refinaries and mines is continuously emitted into the atmosphere as a result
air in the bin such areas is highly polluted. C-MET is developing new class of
photocatalysts which are stable and active under sunlight.
The Centre for Materials for Electronics Technologies (C-MET), Pune
has developed the prototype photo reactor for hydrogen production from
hydrogen sulphide at the rate of 8182.8 and 7616.4 µmol/h/g was obtained
from nanostructured ZnIn2S4 and CdIn2S4, respectively under Natural Sunlight
(UV optical absorption edge at 557nm for ZnIn2S4 and 576nm for CdIn2S4).
The reactor has been designed for the facile operation and considering the
safety aspects. The sparger was fixed as a H2S distributer, which also acts as
a particle disperser. This design is useful for continuous operation at large
scale.
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9.0 Action Plan
9.1 Hydrogen is a byproduct along with the production of caustic soda and
chlorine in the Chlor-Alkali units. These units are continuously working
towards better utilization of hydrogen and have succeeded in achieving 90%
utilization during 2014-15. The remaining hydrogen amounting to around
6600 tonnes may be utilized in energy related applications, since it emits no
pollution except water and heat. This hydrogen may be used directly for the
generation of power / in transportation applications (vehicles) based on IC
engine technology. For fuel cell application, hydrogen may further be purified
(if required), for use in stationary power generation and on-board application
in vehicles / material handling systems (based on fuel cell technology), etc.
9.2 Hydrogen has been produced from the conventional sources i.e.
carbonaceous fuels like natural gas, coal etc. For small capacities hydrogen
production by electrolysis, methanol or ammonia cracking for small, constant
or intermittent requirements of hydrogen in food, electronics and
pharmaceutical industries and for larger capacities steam reforming of
hydrocarbons / syngas are preferred. These sources release CO2 in the
atmosphere. The average rate of growth of CO2 in the atmosphere is around
2.1 ppm per year and its concentration in air has increased from 381.90 ppm
in 2006 to 398.55 ppm in 2014. India has proposed to reduce emissions by
33-35% by 2030 over the 2005 levels by boosting clean (non-fossil &
including renewable) energy in electricity generation to 40% (at least another
150GW) and by adding sinks through trees and forests. Renewable-based
processes like solar- or wind-driven electrolysis and photo-biological water
splitting hold great promise for clean hydrogen production; however,
advances must still be made before these technologies can be economically
competitive. Thus, hydrogen production may be continued from the
conventional (carbonaceous) fuels through the most competitive process
namely auto-thermal reforming (steam reforming and partial
oxidation)process till the technologies for hydrogen production from
renewable sources become economically competitive.
9.3 Biomass has been identified as potential renewable source for
hydrogen production. It is carbonaceous source and produce CO2, which is
released to the atmosphere. Biomass is gasified to hydrogen rich syngas,
which may be reformed and purified to yield pure / near pure hydrogen. The
technology is being developed in the country by IISc, Bangalore. Some other
institutes like NIT, Rourkela and NIT Cochin have also been engaged in R&D
work for hydrogen production through gasification of biomass. IISc developed
a prototype for production of 2 kg/h hydrogen through Oxy-steam gasification
process with hydrogen yield of 100 gm/kg of biomass used.
174
9.4 Electrolysis is a method by which hydrogen may be obtained in pure
form. This hydrogen may be used directly in the fuel cells applications. The
cost of hydrogen production by this method is high due to high capital
investment and operating cost (i.e. electricity consumption). Electricity
generated by the solar energy / wind energy / hydro resource may be used to
nullify carbon emission in the atmosphere, but these technologies require high
capital investment. The electrolyser system consists of various subsystems
like electrochemical stack, power rectifiers, control systems, instrumentation
for monitoring various processes, water purification, pumps, multistage
compressors, pressure vessels, and multiple number of other engineering
subsystems involved and requires integration as per customer requirements
to develop complete system. Except an electrochemical stack, India has core
strength for manufacturing majority of aforementioned subsystems and very
much capable in system engineering. Imported electrolyser stacks in different
combinations may be used and integration can be carried in the country. The
institutions / industry may be identified to work in PPP Model for
commercialization of the balance of plant and simultaneously, the technology
for the production of stack may be procured or developed indigenously.
9.5 Solid polymer electrolyser (SPE) with 20,000 hours of operation are
desirable. SPE is either acid or alkali based, the acid based electrolysis
system requires noble metal catalysts, and alkaline membrane based
electrolysis require cheaper electro catalyst like Nickel. It is ideal to have
membranes based alkaline water electrolysis system integrated with solar
photovoltaic system. However, alkaline based SPE faces numerous
challenges such as chemical stability in the electrochemical device. These
challenges are lesser for either phosphoric acid based electrolysis cells or
alkali based electrolysis systems using diaphragm. Due to these problems,
the following steps are suggested in the sequential order:
(i) Deployment of solar energy powered
a. Acid based electrolysis system
b. Alkali based electrolysis system
for immediate onsite hydrogen production using available technology.
(ii) Development of ectrolysers based on indigenous acid based SPE
(iii) Development of alternate alkaline membrane
(iv) Development of alkaline SPE based electrolyte system
(v) Replacement of old systems by the newly developed systems
9.6 Hydrogen may be produced through dark and photo-fermentation
process. The dark fermentation has certain limitations and can yield hydrogen
in terms of energy recovery ranging 20 to 30 % of total energy. This process
175
may be integrated with photo fermentation, but such a two-stage process is
difficult to commercialise. However, theoretically, 12 moles of H2 /mole of
glucose can be recovered. If the dark fermentation followed by bio-methantion
process may lead to gaseous energy recovery ranging from 50 to 60%. In this
process the same reactor may be used for H2 production and later for bio-
methanation, which would curtail the operational cost. The mixture of
hydrogen and methane so produced is called bio-hymet. The production bio-
hymet could be envisioned as renewable source of energy only when it would
be produced from renewable sources. Any organic compound which is rich in
carbohydrates, fats and proteins could be considered as possible substrate
for bio-hymet production. Another path of hydrogen economy has been
suggested by the integration of fuel cell system with the bio-hydrogen
production system. Such setups may be put strategically near to those places
where supply of feedstock is easily available in adequate quantities. The
electricity generated by such system may electrify villages in a decentralized
manner.
9.7 Bhabha Atomic Research Centre has successfully demonstrated I-S
process in closed loop operation in glass/quartz material in the laboratory. It is
further planned to demonstrate closed loop operation in metallic construction.
Other institutes / organisations will also be roped in depending upon their
capabilities. The broad plan is given below:
(i) Design and demonstration of atmospheric pressure operation all metal
closed loop system (AMCL).
(ii) High pressure operation Bunsen reactor system has been designed
and its commissioning is underway.
(iii) Design and demonstration of high pressure sulfuric acid
decomposition system.
(iv) Design and demonstration of hydroiodic acid distillation and
decomposition system.
(v) Integration of all three high pressure systems to demonstrate, high
pressure closed loop process.
The following challenges have been envisaged for the metallic system,
which are to be dealt with in this endeavor:
(i) Fabrication of exotic material based equipment, such as Tantalum,
Hastelloy, Silicon Carbide etc.
(ii) Development of special seals, compatible for high temperature, high
pressure and corrosive chemicals for metallic system.
(iii) Development of special instrumentation and controls for metallic
system.
176
9.8 ONGC Energy Centre (OEC) is of the view that three potential thermo-
chemical processes (Cu-Cl closed loop cycle, I-S closed loop cycle and I-S
open loop cycle) first be studied at engineering scale and compared before
deciding to take up at the commercial level. The OEC has planned to study
and evaluate alternative materials used in process and plant design, keeping
in view the corrosive nature and use of expensive materials in the process.
The following work has been undertaken by the Centre:
(i) Indigenous membranes are being developed with CSMCRI, Bhavnagar
and expected to be completed by January, 2018.
(ii) Development of partially open-loop I-S cycle involving H2S incineration,
experimental studies on Bunsen reaction and HI decomposition would
be completed within two years with IIP Dehradun.
(iii) Work on “Prolonged stability tests of catalysts for HI decomposition
reaction of I-S cycle have recently been taken-up jointly with IIT-Delhi.
(iv) Suitable materials for design and development of process reactors for
I-S cycle are being identified. The work is in progress.
The OEC has planned to start research on identification, development
and testing of suitable materials for design and construction of large size
indigenous reactors for Cu-Cl process, keeping in view the corrosive nature of
materials used in the Cu-Cl process.
9.9 Photo-electrochemical Water Splitting
Indian Oil Corporation Limited Research and Development Centre,
Faridabad made a plan to conduct laboratory-scale studies on prospective
materials and their performance evaluation. The details are given below:
Core activity 1: Exploration on promising semiconductors/systems:
Extensive R & D is required to be undertaken concerning the photo-
electrochemical measurements for hydrogen generation via photo-splitting of
water by employing the promising semiconductors. Thin films of the
semiconductors would be converted into electrode by adopting the standard
procedure and to be used in PEC water splitting studies. These thin film
working electrodes would be used as photo-sensitive working electrode, in
conjunction with platinum counter electrode and saturated calomel electrode
(SCE, as reference electrode), at varying electrolyte conditions. Current (I) –
Voltage (V) characteristics of PEC cell would be studied, both under darkness
and illumination. The performance of PEC cell would be evaluated. Promising
material-options in this regard that need to be tested at the next level, which
would be involved their integration with pilot-scale hydrogen generation
reactor and the performance evaluation of such reactors both under controlled
conditions as well under real-time solar illumination.
177
Core Activity 2: Scale-up studies and related issues: Solar energy fed
pilot-scale hydrogen generation reactors to perform efficiently under field
conditions will be developed. The above mentioned two semiconductor
systems would be investigated. New promising material/ system would also
be incorporated in the work-plan under this activity. Key work elements
involved the synthesis of large area electrodes including suitable synthesis
methods for preparation of electrodes. First-level up-scaling studies with
existing facilities at Dyalbagh Educational Institute, Agra will be done.
Electrodes of different dimensions need to be fabricated and tested.
Feasibility for scaling of electrodes from 1cm2 to 150 cm2 active area is to be
determined by conducting experiments with state of the art instruments at
IOCL - R&D. Two routes of large area electrodes shall be explored – one
having single large area electrode and the other – several small electrodes
connected in suitable configuration. Empirical modeling of performance
versus increase in the area of electrodes will be done. Maximum feasible size
electrode will be determined that can be incorporated in the reactor. Study on
scaling of counter electrode with respect to increase in the area of working
electrode and optimization of interconnection design for working and counter
electrodes would be done.
III. Studies on reactor design and fabrication.
Core Activity 3: Designing the Reactor: Theoretical modeling of reactor will
be designed and tested. Different losses associated with electrode and
electrolyte interfaces will be studied. Qualitative and quantitative study of
electrolyte and electrode resistance components will be taken up. Feasibility
of packaging electrodes in parallel connections, their associated losses and
optimum size possible for a reactor will be studied.
Core Activity 4: Fabrication of Reactor: Actual design of the reactor will be
taken up after study on electrodes. A lab scale reactor with a twin
compartment reactor will be fabricated to support scale-up activities for
performance evaluation of electrodes of different sizes. Separate
compartments will separate the evolved gases (hydrogen and oxygen).An
electronics circuit will be designed to supply constant external bias to the
electrodes. Initially battery will be used for supply and subsequently efforts will
be laid to try to use photovoltaic panel for supplying external bias to
electrodes. A bigger bench scale reactor having the provision of two
compartments will also be fabricated with a maximum active area of ~
900cm2. Benchmark data will be generated by controlled indoor testing with
large area illumination continuous light solar simulator.
Core Activity 5: Fabrication of Reactor: Performance is to be evaluated
under controlled laboratory conditions. It is planned to set up a continuous
178
solar simulator in laboratory which can illuminate electrodes up to a maximum
area of~ 900 cm2.
Under real-time solar illumination outdoor field conditions testing will be
taken up after laboratory testing. Performance will be evaluated with respect
to the real time data obtained from a weather station at IOCL-R&D.
9.10 Presently, Hydrogen Production by non-thermal plasma assisted direct
decomposition of hydrogen sulphide is at research and development stage
and no commercial technology is available. Electrolysis process consumes
3.6 kWh/Nm3 hydrogen, whereas steam reforming of methane, the traditional
approach for hydrogen production demands still higher energy of 4.3
kWh/Nm3 hydrogen. 40% conversion of hydrogen sulphide by thermal
decomposition can be achieved at temperature ~ 1500K. Nationally, most of
the research in this area has been focused on catalytic/ photocatalytic
decomposition of hydrogen sulphide. Hydrogen sulphide under visible light to
generate hydrogen is an attractive route of solar energy conversion, because
hydrogen is 100% environmentally clean chemical fuel. The Indian Institute of
Technology Hyderabad developed the process of non-thermal plasma
assisted direct decomposition of hydrogen sulphide into hydrogen and
sulphur. Hydrogen production of 0.5 litre/minute was achieved in the
laboratory. The reaction conditions can be still improved to decrease the
energy consumption. Further R&D is required in this area.
9.11 For the photo-splitting of hydrogen sulphide into hydrogen, extensive
work has been carried out in the development of ultraviolet driven
photocatalyst for water and hydrogen sulphide splitting. There is need to
develop prototype photo reactor for hydrogen production from hydrogen
sulphide using solar energy and field trials using gas emitted at refinery sites
using a batch type photoreactor. The research on hydrogen generation from
hydrogen sulfide and water is still at research level. No commercial process
has been developed yet. Nationally, very few groups are working on
photocatalytic splitting of water and hydrogen and hydrogen sulphide into
hydrogen under visible light. Few research group in BARC are working on
photocatalytic degradation of nuclear waste as well as water purification.
Some research teams in IISc, Bangalore are working on TiO2 based
photocatalysts for organic waste degradation. In addition to this, some
researchers in IIT, Mumbai and Madras, CECRI, Karaikudi, IICT, Hyderabad
and few universities in India are working on photodecomposition of organic
pollutants. The Centre for Materials for Electronics Technologies (C-MET),
Pune is working on hydrogen generation by photocatalytic decomposition of
toxic hydrogen sulphide. C-MET is developing new class of photocatalysts
which are stable and active under sunlight. C-MET, Pune has developed the
prototype photo reactor for hydrogen production from hydrogen sulphide at
179
the rate of 8182.8 and 7616.4 µmol/h/g was obtained from nanostructured
ZnIn2S4 and CdIn2S4, respectively under Natural Sunlight. This design is useful
for continuous operation at large scale. There is a scope to carry R& D in this
area.
9.12 The Institute of Minerals and Materials Technology (IMMT),
Bhubaneswar developed functional hybrid nano structures for photo
electrochemical water splitting. The different photo-catalytic materials
developed for hydrogen production through water splitting, which were
continuously operated for 6-7 hours. Among the developed materials like CdS
photo-electrodes and CdS nano-crystal powder photo-catalysts with yield of
800-1000 mg/batch, 0.28 wt% P3HT modified CdS with yield of 4087 µmol/h/g
and CdS-NaNbO3 core-shell nano-rods with yield of 11,901 µmol/h/g, the
CdS-NaNbO3 core-shell nano-rods was found to give maximum hydrogen
production. Research & Development may be continued in this area.
183
10.0 Financial Projections
10.1 Hydrogen Production from Carbonaceous Feed-stock like Natural Gas,
Coal etc. using Thermo-chemical Route
(i) Mission Mode Projects: Scaling-up of the process of partial
reforming of natural gas for the production of H-CNG for the use in
vehicles (upto 2019) - Rs.40 Crore
(ii) Research and Development Projects: Development &
demonstration of hydrogen production by auto-thermal process
(upto 2020) - Rs. 20 Crore
(iii) Basic / Fundamental Research Projects: Dissociation of
gaseous hydrocarbon fuels to hydrogen using solar energy (upto
2022) - Rs. 10 Crore
10.2 Hydrogen Production from Carbonaceous Source like Biomass Feed-
stock as Renewable Source using Thermochemical Route
(i) Mission Mode Projects: Research and development for hydrogen
production by gasification of biomass, including demonstration of
technology at pilot scale (upto 2020) - Rs. 10 Crore
(ii) Research and Development Projects: Hydrogen production by
reformation of bio-oil obtained from fast pyrolysis of biomass (upto
2022) - Rs.5 Crore
10.3 Hydrogen Production using Electrolytic Processes - Low and High
Temperature Electrolysers
(i) Research and Development Projects: Development &
demonstration of 1 Nm3/hr high temperature steam electrolyser
and 5 Nm3/hr indigenously developed solid polymer water
electrolyser (upto 2020) - Rs. 10 Crore
(ii) Research and Development Projects: Development &
demonstration of efficient alkaline water electrolyser (upto 2018)
- Rs. 10 Crore
(iii) Research and Development Projects: Development and
demonstration of clean and sustainable hydrogen production by
splitting water using renewable energies such as solar energy,
wind energy and hybrid systems. This also includes electrolysis,
photo-catalysis and photo-electro-catalysis (upto 2022)
-Rs. 10 Crore
iv) Integration of large capacity electrolysers with wind / solar power
units when there are not in a position to evacuate power to grid for
providing hydrogen (upto 2022). -Rs. 5 Crore
184
10.4 Bio-Hydrogen Production
i) Mission Mode Projects: Development and demonstration of
biological hydrogen production from different kinds of wastes like
effluents from distillery, brewery, paper mills, wastewater from city,
dairy, tannery, slaughter house, chemical & pharmaceutical
industries, agro / food processing industry residues like cane
molasses, noodle and potato processing, poultry litter, de-oiled
algal cakes, food (canteen) waste through dark or/and photo
fermentation. Demonstration of prototypes at various levels
followed by bench scale and pilot plant. After successful
demonstration commercial production may be commenced (Upto
2022) -Rs.20 Crore
ii) Mission Mode Projects: Hydrogen production by water splitting
using photolysis using solar energy (Upto 2022) -Rs.40 Crore
iii) Research and Development Projects: Hydrogen production
together with methane through biological processes from different
kinds of organic wastes, including industrial effluent. Energy
balance and process economic aspects may also be studied (Upto
2019) - Rs.10 Crore
iv) Research and Development Projects:Development of
technology for production of syn-gas (CO+H2)and hydrogen from
reformation of natural gas / biogas using solar energy (up to 2022.
- Rs.5 Crore
10.5 Hydrogen Production through Thermochemical Cycles
Mission Mode Projects: Hydrogen production by water splitting using
thermo-chemical route (open / closed loop Iodine-Sulphur cycle and
Copper – Chlorine cycle) using solar / nuclear heat (upto 2022)
- Rs.50 Crore
10.6 Other innovative method for hydrogen production such as hydrogen
production by non-thermal plasma assisted direct decomposition of
hydrogen sulphide, Photo-splitting of Hydrogen Sulphide including
developmental effort for reduction in energy consumption for hydrogen
production (up to 2022). -Rs.20 Crore
10.7 Projects for utilization of byproduct hydrogen at Chlor-Alkali units /
refineries: Development and demonstration of prototype systems for
purification of by-product hydrogen from Chlor-Alkali units / refineries
for the use in fuel cells to generate power for captive use or its
185
compression for filing in cylinders to use them on-board in hydrogen
fueled vehicles / material handling systems (based on fuel cell
technology) (Upto 2019) - Rs.20 Crore
_______________
Total requirement (Upto 2022) -Rs.285 Crore
______________
186
ACTIVITIES ON HYDROGEN PRODUCTION
MMP: Mission Mode Projects; RD&DP: Research & Development Projects; B/FRP: Basic / Fundamental Research Projects
Sl.
No. Category of Projects
Time Frame (Year) Financial
Outlay
(Rs. in Crore) 2016 2017 2018 2019 2020 2021 2022
1
Mission Mode Projects
20
40
20
40
50
Setting-up of purification unit / compression
system to fill cylinders to utilize surplus
hydrogen from the Chlor-Alkali Units /
Refineries
Scaling-up of the process of partial reforming of
natural gas for the production of H-CNG
Demonstration of closed loop operation of I-S in metallic reactor and both I-S open & closed loop process and Cu-Cl cycle using solar / nuclear heat
SUB-TOTAL 170
Development and demonstration of biological hydrogen production from different kinds of wastes
Phase I Bench Scale
Phase II Pilot Scale
Phase III Commercial Production
Hydrogen production by water splitting through photolysis using solar energy
187
2
Research, Development
& Demonstration
20
10
10
10
10
10 5
5 5
Hydrogen production by gasification of biomass including
demonstration of technology at pilot scale
Development, and demonstration of
electrolyser with indigenous acid based SPE &
alternate alkaline membrane and its
deployment to replace old systems
Development and demonstration of alkaline 1 & 5 Nm3/h high temperature
steam solid polymer water electrolyser and its deployment to replace old
systems
Hydrogen production by Auto-thermal Process
Development of technology for production of syn-gas (CO+H2) and hydrogen from
reformation of natural gas / biogas using solar energy.
Integration of large capacity electrolysers with wind / solar power units, which is not in a
position to evacuate power to grid, for generation of hydrogen and its storage
SUB-TOTAL 85
Development and demonstration of Hydrogen production by splitting water using
renewable energies
Hydrogen production by reformation of bio-oil obtained from fast pyrolysis of biomass
Development & demonstration of
efficient alkaline water electrolyser
188
3.
Basic / Fundamental
Research Projects
10
20
Other innovative method for hydrogen production like hydrogen production by non-
thermal plasma assisted direct decomposition of hydrogen sulphide, Photo-splitting of
Hydrogen Sulphide including developmental effort for reduction in energy consumption
for hydrogen production
SUB-TOTAL 30
GRAND TOTAL 285
Dissociation of gaseous hydrocarbon fuels to hydrogen using solar energy
191
11.0 Conclusions and Recommendations
11.1 Conclusions
11.1.1 Hydrogen has been widely used in chemical industries to manufacture
fertilizers, chemicals, ammonia, saturated fatty acids (vanaspati ghee), etc. Its
use in non-energy applications is expected to increase further in coming years
substantially. It is an energy career and not a primary source of energy. It is
gaining importance as a futuristic clean (pollution free) and sustainable (on
the basis of its production from renewable sources of energy) fuel for
stationary power generation and transportation. Hydrogen may be produced
from direct or indirect source of energy and hydrocarbon. The fossilized
carbonaceous feed stocks, like natural gas, naphtha or coal, etc., (source of
hydrocarbon and chemical energy) are being used for producing hydrogen
through steam reforming, plasma reforming, coal gasification, partial
oxidation, and co-conversion using steam. Hydrogen is also being produced
from electrolysis of water.
11.1.2 The conventional carbonaceous feed stocks are limited. The non-
fossilized renewable carbonaceous materials, such as biomass, agro-waste,
rubber wastes, urban solid waste, de-oiled seed cakes, waste cooking oil etc.
contain carbon and may be used for producing hydrogen. All these feed-
stocks emit CO2 (a greenhouse gas) and other polluting gases. Hydrogen is
also produced through low or high temperature electrolysis of water, which is
abundantly available on earth. The electricity used for this process may be
generated using fossil fuels or through the use of solar energy / wind energy.
11.1.3 In view of the current developments and efforts at the national level for
the deployment of fuel cells as the back-up power system for the telecom
towers and demonstration of vehicles based on the hydrogen IC engine
technology as well as fuel cells, it is the right time to set-up hydrogen
production facilities on small, medium and large scales to derive meaningful
insights regarding realisation and management of hydrogen energy
infrastructure in the country.
11.1.4 Substantial quantity of surplus hydrogen is available as byproduct
hydrogen. It may be tapped to meet immediate requirement for research,
development and demonstration of various hydrogen based projects. The
Government may consider extending support to create facilities for tapping
this hydrogen. In India, currently the byproduct hydrogen amounting to around
6600 tonnes hydrogen (10% of total byproduct hydrogen) is available as
unutilized with the Chlor-Alkali units. This hydrogen may be further purified (if
required), compressed, bottled and transported to the sites for use in
stationary power generation and on-board application in vehicles / material
192
handling systems, etc. This surplus volume of by-production hydrogen is,
however, quite small to meet the future needs of the gas for energetic uses. A
concerted effort is required to transform the laboratory results into hydrogen
production facilities.
11.1.5 Biomass can be processed (pyrolysed / gasified) for obtaining
hydrogen rich syn-gas. The hydrogen needs to be separated out and purified
to different levels of purity depending on the application needs from the
hydrogen rich syn-gas. The biomass is considered to be easily available in
large quantities. The research outcome of biomass gasification suggests
addressing to the need of hydrogen generation from biomass through the
thermo-chemical conversion process. The R&D experience in the country on
the biomass gasification is rich and can be utilized for technology
development of hydrogen production. Internationally, hydrogen generation by
gasification is being pursued and shortlisted as an economical way to address
to hydrogen production problem.
11.1.6 Water can be decomposed into hydrogen and oxygen through
electrolysis. It is an energy intensive process. The available technologies in
the world’s market are alkaline and solid polymer electrolyte (SPE) based
water electrolyser. Alkaline water electrolysis is cheaper due to use of nickel
catalysts, but efficiency is lower (60-75%) than that (65–90%) of SPE water
electrolysers, which are expensive due to the use of noble metal catalyst (e.
g. platinum) and are operated at higher current densities. The SPE water
electrolysers are possibly, capable of producing cheaper hydrogen, if its
production is taken up on large scale. The efficiency of SPE water electrolyser
is more at higher temperature and pressure (around 120-200 bar). In high
pressure electrolysis external hydrogen compressor is eliminated and hence
around 3 % as average energy consumption for compression of hydrogen is
saved. This SPE based electrolysis process can also be operated with the
electricity generated from the solar photovoltaic systems or wind mills, which
have large potential. Several large installations coupling solar energy or wind
farms with water electrolysers have come up world over. Most of these are
implemented through consortium of several companies. SPE technology up
to 1 Nm3/h has been developed indigenously and its technology has been
transferred to industry.
11.1.7 The thermo-chemical cycles are processes, where water is
decomposed into hydrogen and oxygen via a series of chemical reactions
using intermediates, which are recycled. As the heat can be directly used,
these cycles have the potential of a better efficiency than alkaline electrolysis.
The required energy can be either provided by nuclear energy / solar energy.
The iodine-sulfur closed & open loop (I-S) cycle and Cu-Cl closed loop cycle
are most promising and efficient thermo-chemical water splitting technologies
193
for the massive production of hydrogen. BARC has successfully demonstrated
in the I-S closed loop operation in glass / quartz materials in the country. It
has been planned to take-up demonstration of the same process in metal
construction. The ONGC Energy Centre (OEC) has set-up an engineering
scale plant for Cu-Cl closed loop cycle process, which will be operated for one
year and alternative materials for platinum as electrode has been undertaken
for development at this plant. OEC is also working with CSMCRI, Bhavnagar
on indigenous development of polymeric charged membranes for
thermochemical hydrogen generation processes; with IIP, Dehradun for the
development of partially open-loop I-S cycle involving H2S incineration &
experimental studies on Bunsen reaction and HI decomposition and with IIT
Delhi on prolonged stability tests of catalysts for HI decomposition reaction of
I-S cycle. OEC has also planned to carry out research on identification,
development and testing of suitable materials for design and construction of
large size indigenous reactors for Cu-Cl process, keeping in view the
corrosive nature of materials used in the Cu-Cl process.
11.1.8 Hydrogen can be produced from dark fermentation (equivalent to 20 to
30% of the total energy content of the feed). This process followed by photo
fermentation, 12 moles of H2 /mole of glucose can be recovered theoretically,
but it is difficult to integrate the two processes for commercialization. The
dark fermentation can be integrated with the bio-methantion process (to yield
50-60% gaseous energy recovery), where methane may be produced from
the spent media of the dark fermentation, which is rich in volatile fatty acids
that is an ideal substrate for methanogens. The most attractive point of such
a process is that both the processes may be carried out one after the other in
the same reactor (H2 production followed by bio-methanation. So, separate
reactor is not required. This would lead to decrease in operational cost of the
entire process. Bio-hythane production may be envisioned as renewable
source of energy only when it would be produced from renewable sources.
Any organic compound which is rich in carbohydrates, fats and proteins could
be considered as possible substrate for bio-hymet production.
11.1.9 Steam-methane reforming (SMR) and coal gasification are the
technologies established globally for hydrogen production. They are
commercially ready, though the cost is high. Still there is scope for carrying
out R&D activities for coming out with cheaper catalysts and efficient
reforming units.
11.1.10 Auto-thermal reformers (ATRs) combine some of the best features of
steam reforming and partial oxidation systems. Several companies are
developing small auto-thermal reformers for converting liquid hydrocarbon
fuels to hydrogen for the use in fuel cell systems. The auto-thermal reformer
requires no external heat source and no indirect heat exchangers. Heat
194
generated by the partial oxidation is utilized to drive steam reforming reaction.
This is more compact than steam reformers, and it will have a lower capital
cost and higher system efficiency than partial oxidation systems. Auto-thermal
reformers are being developed for PEMFC system by a number of groups.
11.1.11Solar hydrogen production from direct photo electrochemical (PEC)
water splitting is the ultimate goal for a sustainable, renewable and clean
hydrogen economy. In PEC water splitting, hydrogen is produced from water
using sunlight and specialized semiconductors called photo electrochemical
materials, which use light energy to directly dissociate water molecules into
hydrogen and oxygen. Indian R & D organisations are engaged in the
extensive R & D of photo-electrochemical technology.
11.1.12 The efforts are required to develop other/new innovative method for
hydrogen production, like hydrogen production by non-thermal plasma
assisted direct decomposition of hydrogen sulphide, Photo-splitting of
Hydrogen Sulphide including developmental effort for reduction in energy
consumption for hydrogen production
11.1.13 To start with, the country may adopt technologies from abroad,
especially to build large installations, for which we may not have the expertise
straightaway. For medium and small installations, Indian R & D organisations
and industries could chip in well.
11.1.14 The Ministry may constitute a group of experts, which may review
from time to time, the plan and actual development and deployment of
hydrogen based systems and devices in the field in order to assess the future
hydrogen requirement. The group will then suggest ways and means to fulfil
hydrogen requirement through various technologies being developed in the
country or to be imported from abroad.
11.2 Recommendations
11.2.1 India has announced its Climate Action Plan for reduction of emissions
by 33-35% by 2030 over the 2005 levels, boosting clean (non-fossil &
including renewable) energy in electricity generation to 40% (at least another
150GW), while adding carbon sinks — tree and forest cover to remove carbon
dioxide from the atmosphere — amounting to 2.5-3 billion tonnes of CO2 by
2030. Thus, the country has targeted to enhance nuclear power from 5 GW
to 63 GW by 2032 and doubling wind capacity to 60 GW by 2022, solar
capacity from 4 GW to 100 GW by 2022.
11.2.2 In view of the India’s Climate Action Plan, the technologies for
hydrogen production may be targeted accordingly. The first target may be
195
focused on the efficient utilization of byproduct hydrogen of the Chlor-Alkali
units. At the end of the financial year 2014-15, only 10% of byproduct
hydrogen is available. Remaining 90% byproduct hydrogen is being utilized,
~40% in chemical industries,~37% as fuel in boiler heating for captive use and
~13% being bottled for sale.After utilization of surplus un-utilized 10%
byproduct hydrogen, next target may be made to utilize ~37% hydrogen
efficiently, which is currently being used as fuel in boiler heating for captive
use. Alternate sources may be used for heating purpose. In-house stationary
power generation may be one of the most effective ways of utilizing hydrogen.
The government may consider incentivizing this application of hydrogen for its
cost effective utilization.
11.2.3 The present facilities of hydrogen production may be utilized to supply
hydrogen for purpose of carrying out the activities on the research,
development and demonstration for hydrogen production and its applications
for stationary power generation and vehicles.
11.2.4 From the gap between international and national state of art of
technologies, it has been visualized that India has to take a leapfrog to come
at par with the international level. This gap is to be planned in time bound
project mode (with foreign collaboration, if required) and therefore, the
projects may be classified in the following three categories viz. National
Mission Projects, Research & Development projects and Basic / Fundamental
Research projects:
11.2.5 The National Mission Projects may cover projects with the participation
of the industry for the technologies, which are mature or near maturity for
commercialization after the short development time and those may be taken
up on large scale demonstration. Such projects would be multi-disciplinary in
nature. These projects may involve more than one institution (with a lead
institution), which are already involved in the implementation of research &
development activities. The outcome of such projects should be a compact,
comprehensive, marketable and user friendly product. The resources and the
infrastructure facilities of the involved institutions may be pooled together to
achieve the common goal.
11.2.6 The Research & Development projects may include the projects in
which the technology is at the stage of prototype development and its
demonstration as a proof of concept. Industry participation should be
preferred for these projects. Such projects may be undertaken on different
subjects like design, research & development of the individual system
components, sub-systems, integration of systems after the basic research has
shown encouraging results. Engineering research and development must be
a part of such projects.
196
11.2.7 The Basic / Fundamental Research projects will cover search /
development of new materials for the development of components, catalysts
and new processes in the area of hydrogen production.
11.2.8 These categories may be further elaborated as under:
a) Mission Mode Projects
(i) Development and demonstration of biological hydrogen
production from different kinds of wastes like effluents from
distillery, brewery, paper mills, wastewater from city, dairy,
tannery, slaughter house, chemical & pharmaceutical
industries, agro / food processing industry residues like cane
molasses, noodle and potato processing, poultry litter, de-
oiled algal cakes, food (canteen) waste through dark or/and
photo fermentation. Demonstration of prototypes at various
levels followed by bench scale and pilot plant. After
successful demonstration commercial production may be
commenced.
(ii) Research and development for hydrogen production by
gasification of biomass, including demonstration of
technology at pilot scale.
(iii) Hydrogen production by water splitting using photolysis and
thermo-chemical route using solar and nuclear heat.
b) Research and Development Projects
(i) Hydrogen production together with methane through
biological processes from different kinds of organic wastes,
including industrial effluent. Energy balance and process
economic aspects may also be studied.
(ii) Development & demonstration of 1 Nm3/h high temperature
steam electrolyser (HTSE) and 5 Nm3/h indigenously
developed solid polymer water electrolyser (SPWE).
(iii) Development & demonstration of efficient alkaline water
electrolyser.
(iv) Development and demonstration of clean and sustainable
hydrogen production by splitting water using renewable
energies such as solar energy, wind energy and hybrid
systems. This also includes electrolysis, photo-catalysis and
photo-electro-catalysis.
197
c) Basic / Fundamental Research Projects
(i) Dissociation of gaseous hydrocarbon fuels to hydrogen using
solar energy.
(ii) Any other innovative method for hydrogen production, like
hydrogen production by non-thermal plasma assisted direct
decomposition of hydrogen sulphide, Photo-splitting of
Hydrogen Sulphide, including developmental effort for
reduction in energy consumption for hydrogen production
(d) Projects for Utilization of Byproduct Hydrogen at Chlor-Alkali
Units / Refineries
Development and demonstration of prototype systems for
purification of by-product hydrogen from Chlor-Alkali units /
refineries for the use in fuel cells to generate power for captive
use or its compression for filing in cylinders to use them on-
board in hydrogen fueled vehicles / material handling systems
(based on fuel cell technology).
201
12.0 Bibliography
12.1 Hydrogen Production from Carbonaceous Biomass Feed-stock
using Thermochemical Route
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12.3 Hydrogen Production using Electrolytic Processes - Low and High
Temperature Electrolysers
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Prentice- Hall, Englewood Cliffs, NJ, USA, p. 425, 1968.
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Science, vol. 259, pp. 10-26, 2005.
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Nishijima, S., Polymer Degradation and Stability, vol. 95, no. 1, pp.
1-5, 2010.
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12.4 Bio-Hydrogen Production
1. Armor, J. N., “The Multiple Roles for Catalysis in the Production of
H2”, Applied Catalysis A: General. 1999; 176: 159-176.
2. Benemann J R. Hydrogen Biotechnology: Progress and Prospects.
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Production by Clostridium thermolacticum during Continuous
Fermentation of Lactose, Int J Hydrogen Energy. 2004; 29(14):
1479-1485.
5. Oh, Y. K., Kim S. H., Kim, M. S., and Park, S., Thermophilic
Biohydrogen Production from Glucose with Trickling Biofilter.
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Fuel Cells and Biological Hydrogen Production. ACS, Division of
Environmental Chemistry - Preprints of Extended Abstracts. 2004;
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Unsaturated, Packed-bed Bioreactor. ACS National Meeting Book
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of Abstracts 2004: 228(1); 300. Abstracts of Papers - 228th ACS
National Meeting; Philadelphia
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Computational Model for Hydrogen Production from Bio-ethanol to
Feed a fuel Cell Stack, Int J Hydrogen Energy. 2012; 37(4): 3108-
3129.
9. Vatsala, T.M., Raj, M., Manimaran, A., A Pilot-scale Study of
Biohydrogen Production from Distillery Effluent using Defined
Bacterial Co-culture. Int J Hydrogen Energy. 2008; 33(20): 5404-
5415.
12.5 Hydrogen Production through Thermochemical Cycles (Iodine-
Sulphur Cycle)
1. Zhang, P., et al., Overview of Nuclear Hydrogen Production
Research through Iodine-Sulfur Process at INET, International
Journal of Hydrogen energy, 35 (2010 ) 2883 – 2887.
2. IAEA Nuclear Energy Series, No. NP-T-4.2 Hydrogen Production
Using Nuclear Energy, 2013
3. Status of HTTR Project in JAEA, Hirofumi OHASHI, Technical
Meeting on the Safety of High Temperature Gas Cooled Reactors in
the Light of the Fukushima Daiichi Accident, 8 - 11 April 2014, IAEA
Headquarters, Vienna, Austria
4. Greg F. Naterer, Ibrahim Dincer, Calin Zamfirescu Hydrogen
Production from Nuclear Energy, Springer, 2013
12.6 Hydrogen Production by Photo-electrochemical Water Splitting
1. Kudo, A., Miseki, Y. Heterogeneous photocatalyst materials for
water splitting. Chem. Soc. Rev. 2009, 38, 253–278.
2. Kamat, P.V. Graphene-based nano architectures. Anchoring
semiconductor and metal nano particles on a two-dimensional
carbon support. J. Phys. Chem. Lett. 2010, 1, 520–527.
3. H. Matsushima, T. Nishida, Y. Konishi, Y. Fukunaka, Y. Ito and K.
Kuribayashi, Electrochim. Acta, 48 (2003) 4119.
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209
ANNEXURE
13.0 Publications and Patents pertaining to Hydrogen
Production through Thermochemical Routes
(I-S & Cu-Cl)
13.1 Publications
1. G. D. Yadav, P.S. Parhad, A. B. Nirukhe and S. B. Kamble. Study of
Hydrogen Generation using Copper and Hydrochloric Acid. Presented at
Chemcon-2008, IIChE Annual congress held in Chandigarh, India
during December 27-30, 2008.
2. D. Parvatalu, A. Bhardwaj and B.N. Prabhu.Technical challenges in
generation of Hydrogen through thermo-chemical processes: ONGC
perspective. Poster paper presented at PETROTECH-2009 held in
Delhi, India during January 11-15, 2009.
3. A. Bhardwaj, D. Parvatalu, and B.N. Prabhu. Closed-loop Thermo-
chemical Cycles for Hydrogen Production: Fuel for Tomorrow. Poster
paper presented PETROTECH-2009 held in Delhi, India during
January 11-15, 2009.
4. A. Bhardwaj, D. Parvatalu, and B.N. Prabhu. Hydrogen Production by
Closed-loop Thermo-chemical Cycles: A Review of S-I Process. Paper
presented at the National Conference on Energy held at Punjab
University, Chandigarh, India during March, 2009.
5. V. Immanuel, K. U. Gokul, S. Sant and A. Shukla. Membrane Electrolysis
of Bunsen Reaction. Presented at CHEMCON-2009, IIChE annual
congress held in Visakhapatnam, India duringDecember 27-30,
2009,
6. D. Parvatalu, A. Bhardwaj and B. N. Prabhu. Electrochemical Routes
Need Better Understanding in Managing Closed- loop Hybrid Thermo-
chemical Hydrogen Generation Cycles. Paper presented at 15th National
convention of Electrochemists held at VIT-University, Vellore, India
during February18-19, 2010.
7. A. Bhardwaj, D. Parvatalu, and B.N. Prabhu. Study of the Alternate
Route in Closed-loop Thermo-chemical Cycles for Hydrogen Production:
fuel for tomorrow. Poster presentation at PETROTECH-2010 held in
Delhi, India during October 31-November 4, 2010.
210
8. A. Bhardwaj, D. Parvatalu, B.N. Prabhu and N.J. Thomas. Future Energy
and Hydrogen. Oral presentation at 17th IORS, held in Mumbai, India
during September 9-10, 2010.
9. D. Parvatalu, Anil Bhardwaj and B.N. Prabhu. Impact of Electrochemical
Routes on thermochemical Hydrogen Generation Technologies. Poster
presentation at ISAEST-9, held in Chennai, India during December 2-
4, 2010.
10. V. Immanuel, K. U. Gokul and A. Shukla. Membrane Electrolysis of
Bunsen Reaction for the Iodine-Sulfur Process for Water Splitting.
Presented at ISAEST-9, held in Chennai, India during December 2-4,
2010.
11. P. K. Sow and A. Shukla. Investigations on Electro-electrodialysis Cell
for Concentration of HIx. Presented at ISAEST-9, held in Chennai, India
during December 2-4, 2010.
12. G. D. Yadav, A. B. Nirukhe and P.S. Parhad. Kinetic Study of Hydrolysis
of Cupric Chloride in Cu-Cl Thermochemical Hydrogen Production.
Presented at CHEMCON-2010, IIChE annual congress held at
Annamalai University, Chidambaram, India during December 27-29,
2010.
13. G. D. Yadav, P.S. Parhad and A. B. Nirukhe. Study of Electrolysis of
Cuprous Chloride. Presented at CHEMCON-2010, IIChE annual
congress held at Annamalai University, Chidambaram during
December 27-29, 2010.
14. P. K. Sow, S. Santand A. Shukla. EIS Studies on Electro-electrodialysis
Cell for Concentration of Hydroiodic Acid. Int J Hydrogen Energy, 2010;
35: 8868–8875.
15. D. Parvatalu, Anil Bhardwaj and B.N. Prabhu. Development of
thermochemical Hydrogen Production by Closed-loop Cycles: ONGC
initiatives. Oral presentation at ICRE-11 held at CNRE, Univ.
Rajasthan, Jaipur, India during January 17-21, 2011.
16. D. Parvatalu, A. Bhardwaj and B.N. Prabhu. Gearing up for Large Scale
Thermochemical Hydrogen Generation Technologies: ONGC Initiatives.
Oral presentation at ICSN 2011 held at Univ. Mumbai, Mumbai, India
during February 14-16, 2011.
17. D. Parvatalu, A. Bhardwaj and B.N. Prabhu. Opportunities and
Challenges Associated with Thermochemical Hydrogen Generation
Technologies: A Perspective in Indian Context. Presented at ICAER
211
2011 held at IIT-Bombay, Mumbai, India during December 9-11,
2011.
18. D. Parvatalu, A. Bhardwaj and B.N. Prabhu. Application of
Electrochemical Technologies in Establishing Closed-loop
Thermochemical Hydrogen Generation Cyclic Processes: ONGC
Initiatives. Oral Presentation at NCE-16 (National Convention of
Electrochemists) held at P.S.G.R.K. College, Coimbatore, India
during December 15-16, 2011.
19. K. Kondamudi, P. Kotari and S. Upadhyayula. Numerical Study of
SulfurtriOxide Decomposition over Complex Catalyst Shapes and Sizes
in S-I Cycle for Hydrogen Production. Presented at Europacat X held at
University of Glasgow, Glasgow, UK during August 28 – September
2, 2011.
20. K. Kondamudi, A.N. Bhaskarwar, S. Upadhyayula, B.N. Prabhu, Anil
Bhardwaj and D. Parvatalu. Kinetic Studies of Sulfuric Acid
Decomposition over Alumina Supported Iron (III) Oxide Catalyst in the SI
Cycle for Hydrogen Production. Presented at ICRE-2011, held in
Jaipur, India during January 17-21, 2011.
21. K. U. Gokul, V. Immanuel, S. Sant and A. Shukla. Membrane Electrolysis
for Bunsen Reaction of S-I Cycle. J. Membr. Sci., 2011, 380, 13-20.
22. V. Immanuel, K. U. Gokul and A. Shukla. Membrane Electrolysis of
Bunsen Reaction in the Iodine – Sulfur Process for Hydrogen Production.
Presented at ICRE-2011 held in Jaipur, India during January 17-21,
2011
23. P. K. Sow and A. Shukla. Electro-Electrodialysis for Concentration of
Hydroidic Acid. Presented at ICRE-2011 held in Jaipur, India during
January 17-21, 2011.
24. K. Kondamudi and S. Upadhyayula. Kinetic Studies of Sulfuric Acid
Decomposition over AL–Fe2O3 Catalyst in the Sulfur-iodine Cycle for
Hydrogen Production. Int. J. Hydrogen Energy, 2012, 37(4), 3586–
3594.
25. P. K. Sow and A. Shukla. A Chronopotentiometry based Identification of
Time-varying Different Transport Resistances of Electro-electrodialysis
Cell used for Concentration of HIx Solution. Int. J. Hydrogen Energy.
2013, 38, 3154-3165
26. P.K. Sow, D. Parvatalu, A. Bhardwaj, B. N. Prabhu and A. N.
Bhaskarwar. Impedance spectroscopic determination of effect of
temperature on the transport resistances of an electro-electrodialysis cell
212
used for concentration of Hydroidic Acid. J. Applied Electrochem, 2012,
43 (11) 31-41.
27. P. K. Sow and A. Shukla. Effect of Asymmetric Variation of Operating
Parameters on EED Cell for HI Concentration in I-S Cycle for Hydrogen
Production. Int. J. Hydrogen Energy, 2012, 37(19), 13958-13970.
28. V. Immanuel, D. Parvatalu, A. Bhardwaj, B. N. Prabhu, A. N.
Bhaskarwar and A. Shukla. Properties of Nafion 117 in Highly Acidic
Environment of Bunsen Reaction of I-S Cycle. J. Membr. Sci., 2012,
409-410, 137-144.
29. V. Immanuel and A. Shukla, “Effect of Operating Variables on
Performance of Membrane Electrolysis Cell for Carrying Out Bunsen
reaction of I-S Cycle” Int. J. Hydrogen Energy, 2012, 37, 4829-4842.
30. P. K. Sow and A. Shukla. Electro-electrodialysis for Concentration of
Hydroidic Acid. Int. J. Hydrogen Energy, 2012, 37, 3931-3937.
31. V. Immanuel, K. U. Gokul and A. Shukla. Membrane Electrolysis of
Bunsen Reaction in the Iodine-Sulfur Process for Hydrogen Production.
Int. J. Hydrogen Energy, 2012, 37, 3595-3601.
32. P. K. Sow and A. Shukla. A Chronopotentiometry based Identification of
Time-varying Different Transport Resistances of Electro-electrodialysis
Cell Used for Concentration of HIx Solution. Int. J. Hydrogen Energy,
2013, 38(8), 3154-3165.
33. D. Parvatalu, S. Banerjee and B.N. Prabhu. Envisaged Technical
Barriers in Converting Electrochemical Solutions to Hybrid-
Thermochemical Technologies: ONGC Perspective. Paper presented at
ISAEST-10held in Chennai, India during January 28-30, 2013.
34. A.B. Nirukhe, P.S. Parhad, A. Bhardwaj, D. Parvatalu and G. D. Yadav.
Hydrogen Production by Non-Catalytic Decomposition of Hydroidic Acid.
Paper accepted for presentation at the International Conference on
Advances in Chemical engineering (ICACE-2013)to be held at NIT,
Raipur, India during March, 8-9, 2013.
35. S. Kamini, S. Banerjee, D. Parvatalu and B.N. Prabhu. Hydrogen
Production by Thermochemical Iodine-Sulfur Cycle: Process Simulation
Studies of Bunsen Section. Paper presented at the International
Conference on Advances in Chemical engineering (ICACE-
2013)held at NIT, Raipur, India during April 5-6, 2013.
36. K. Kondamudi and S. Upadhyayula, “Decomposition of Sulfuric Acid
over Mixed Metallic Oxides - A Comparative Study for Oxygen Evolving
213
Step in S-I Cycle for Hydrogen Production”, EUROPACAT XI
Conference, LYON, France, September 1-6, 2013.
37. D. Parvatalu and B.N. Prabhu. Material Issues Dictate Hydrogen
Generation by Thermochemical Water Splitting Technologies: ONGC
Energy Center Perspective. Presented at CORCON-2013, New Delhi.
38. D. Parvatalu, S. Banerjee and B.N. Prabhu. Recent Developments in
Hydrogen Generation using Iodine- Sulfur Thermochemical Water
Splitting Cycle: ONGC Energy Center efforts, PETROTECH-2014held in
Delhi, India during January 12-15, 2014.
39. D. Parvatalu. Development of Thermochemical Hydrogen Generation
Technologies using Water Splitting Processes: ONGC Energy Center
Perspective. Invited lecture at National workshop on “Fuel Cell
Technology: Basic science to Application” held at MANIT, Bhopal
during March 24-25, 2014
40. D. Parvatalu. Hydrogen is the Key to Success of Renewable Energy
Campaign: ONGC Energy Centre perspective. Invited talk at the
National Seminar during 17-18th November 2014 at Univ. Kerala,
Trivandrum organized by Indian Association for Hydrogen Energy and
Advanced Materials
41. Kamini Shivakumar, S. Banerjee and D. Parvatalu. Simulation studies
on HI Decomposition in Thermochemical Iodine-Sulfur Cycle. Paper
presented at CHEMCON-2014, the 67th Annual Session of the Indian
Institute of Chemical Engineers to be held at Punjab University,
Chandigarh, from 27th – 30th December, 2014.
42. D. Parvatalu, An Overview of Material Requirements for Copper-Chlorine
Thermochemical Cycle: ONGC Energy Centre Perspective. Paper
published in Society for Materials Chemistry Quarterly Bulletin
issued by BARC, 2014
43. D. Parvatalu. Development of Closed-loop Thermochemical Water
splitting Processes for Hydrogen Generation: ONGC Energy Centre
Initiatives. Presentation at 3rd International Conference on Hydrogen
and Fuel Cell during 7-9 December 2014 at Udaipur.
44. D. Parvatalu. Role of Catalysts in the Development of the Iodine-
Sulfur and Copper-Chlorine Thermochemical Hydrogen Generation
Technologies. Presented at 22nd National Symposium on Catalysis
(CATSYMP 22) during 7-9.01.2015 at CSMCRI Bhavnager.
45. N. Sathaiyan, V. Nandakumar, G. Sozhan, J. Ghandhiba Packiaraj, E.T.
Devakumar, D. Parvatalu, Anil Bhardwaj and B.N. Prabhu. Hydrogen
214
Generation through Cuprous Chloride-Hydrochloric Acid
Electrolysis. International Journal of Energy and Power Engineering, 27
January 2015. [Pages 15-22]
13.2 Details of Patents
Sl.
No.
Patent title Institutions Patent Details
1 Hydrogen Production Method by
Multi-Step Copper-Chlorine
Thermochemical Cycle
OEC and ICT,
Mumbai
National and
International*
2 Electrochemical Cell Used for the
Production of Copper Using Cu-Cl
Thermochemical Cycle
OEC and ICT,
Mumbai
National and
International*
3 Effect of Operating Parameters on
the Performance of
Electrochemical Cell in Copper-
Chlorine Cycle
OEC and ICT,
Mumbai
National and
International*
4 High Performance Supported
Metallic/Mixed Metallic Catalyst
for Sulfuric Acid Decomposition in
Sulfur-Iodine (SI) Cycle for
Hydrogen Production
OEC and IIT,
Delhi
National*
5 Process for Catalytic
Decomposition of Sulfuric Acid
over High Performance Supported
Metallic/Mixed Metallic Catalyst in
SI Cycle
OEC and IIT,
Delhi
National*
6 Highly active supported bimetallic
(Ni-Pt) catalyst for hydrogen
iodide (HI) decomposition and
synthesis procedure thereof
OEC and IIT,
Delhi
National*
7 Vanadia supported Pt catalyst
and use thereof for hydrogen-
iodide decomposition in sulfur-
iodine (I-S) cycle for hydrogen
production.
OEC and IIT,
Delhi
National*
The US and Japan patents on “Hydrogen Production Method by Multi-Step
Copper - Chlorine Thermochemical Cycle” have been granted.
*********