Coal Asia 2012Coal Asia 2012

Gasification ‐ Developments  in Syngas UtilizationG.S.DangG.S.Dang

gurbax49@gmail.com

3rd Annual International Summit Solution for Sustainable Environment & Energy Supply

27 ‐ 28 February 2012NDCC II Convention Centre NDMC Complex New Delhi IndiaNDCC II Convention Centre, NDMC Complex, New Delhi, India

CONTENTSCONTENTS

• IntroductionIntroduction

• Gasification process / chemistry

d k & f G ifi• Feedstocks & type of Gasifiers

• Gas cleanup

• Gas applications

• DevelopmentsDevelopments

• Summary 

World Energy Outlook

Source: IEA WEO 2007

Supply / Demand “gap”

Coal Production –Consumption in IndiaCoal Production  Consumption in India

As on 30-11-2011 Source : CEA

Indian Power Sector at a Glance

Fuel MW %age

Total Thermal 121805 98 65 66Total Thermal 121805.98 65.66

Coal 102,863.38 55.45

Gas 17 742 85 9 56Gas 17,742.85 9.56

Oil 1,199.75 0.64

Hydro (Renewable) 38 748 40 20 88Hydro (Renewable) 38,748.40 20.88

Nuclear 4,780.00 2.57

RES** (MNRE) 20,162.24 10.86RES (MNRE) 20,162.24 10.86

Total 1,85,496.62 100.00

Renewable Energy Sources(RES) include SHP, BG, BP, U&I and Wind EnergySHP= Small Hydro Project ,BG= Biomass Gasifier ,BP= Biomass Power, U & I=Urban & Industrial Waste Power, RES=Renewable Energy Sources 

Unconventional Oil production

Gasification & Syngas ProductionGasification & Syngas Production

History of Gasification

• Used during World War II to convert coal into transportation fuels (Fischer – Tropsch)transportation fuels (Fischer Tropsch)

• Used extensively in the last 50+ years to convert coal and heavy oil into hydrogen for the production ofand heavy oil into hydrogen – for the production of ammonia / urea fertilizer

Chemical industry (1960’s)• Chemical industry (1960’s)

• Refineries / oil industry (1980’s)

• Global power industry (recent applications)

What is Gasification?

• The gasification process converts any carbon-containing material into a synthesis gas composed primarily of carbon monoxide and hydrogen (CO + H2).

• Syngas can be used as a fuel to generate electricity or steam or used as a basic chemical building block for a largechemical building block for a large number of uses in the petrochemical and refining industries.

• Gasification adds value to low- or negative-value feedstocks by converting them to marketable fuels and products.p

Gasification Chemistry

Gasification with OxygenC + 1/2 O2 CO Gasifier Gas

CompositionCombustion with Oxygen

C + O2 CO2

Gasification with Carbon Dioxide

Residue/ CoalComposition

(Vol %)

H2 25 - 30CO 30 - 60Gasification with Carbon Dioxide

C + CO2 2CO

Gasification with SteamC + H O CO + HOxygen

CO 30 60CO2 5 - 15H2O 2 - 30CH4 0 - 5

C + H2O CO + H2

Gasification with HydrogenC + 2H2 CH4

OxygenH2S 0.2 - 1COS 0 - 0.1N2 0.5 - 4Ar 0.2 - 1

Water-Gas ShiftCO + H2O H2 + CO2

Methanation

Steam

Ar 0.2 1NH3 + HCN 0 -0.3

Ash/Slag/PMMethanation

CO + 3H2 CH4 + H2O

Gasification Technology

A partial oxidation process that can convert any hydrocarbon h d h d

The Basic Chemistry

into hydrogen hydrogen and carbon monoxide (synthesis gas or syngas).

(CH)n + O2 H2 + CO(CH)n + O2 H2 + COFor example:

2 CH4 + O2 4H2 + 2 CO

[ Methane] [Oxygen] [Hydrogen] [Carbon Monoxide]

12

Process Conditions: 1,000 – 1,500 Deg C, 30 – 70 bar

Gasification Process/ProductsGasification  Process/Products 

Products – Fuels/ Chemicals , Hydrogen, power

Gasification Chemistry(Oxidant ; Air or Oxygen )(Oxidant ; Air or Oxygen )

• All gasification processes require an oxidant (air, i h d i ) f th ti l oxygen or oxygen enriched air ) for the partial

oxidation reactions• Gasifiers built for chemical applications (1935

onwards) mostly use oxygen ( >90 mol% purity) ; nitrogen being detrimental to the downstream synthesis process ( also loss of cold gas efficiency;synthesis process ( also loss of cold gas efficiency;82 % at 100% O2 to 61% with air)

• For gasifiers producing syngas for power generationthe choice is in fa o of o gen in case of la ge the choice is in favour of oxygen in case of large scale projects

• For small scale projects (<50 MWe), mostly operating with biomass or waste, air is the choice

Gasification ChemistryGasification Chemistry

• Steam is used as moderator

• Temperature of steam (300-400oC) corresponds to that of saturated steam at pressure (40 atm) to that of saturated steam at pressure (40 atm)

prevailing in the gasifier (to avoid any condensation)

C b d d d l•Carbon dioxide use as moderator is unusual

•When CO2 is used as a transport gas for pulverized 2 p g pcoal in entrained bed gasifiers then it also acts as moderator

Gasifier feedstocks

Biomass/waste, 5%

Natural gas, 10%

Petcoke, 3%

5%

Coal, 49%

Petroleum, 37%

Utilization of gasification capacity in the world (in year 2007)

Gaseous fuel, 6%

Liquid fuels, Power, 19%30%

Chemicals, 45%45%

GasificationGasification

Refinery Application

REFINERY

Crude oil

Steam

Air emissions

Power

Gasoline / Diesel

DistillatesREFINERYPowerHydrogen

HSFO

f

O2/N2 H2 Power Steam

Gasification

Market Drivers for GasificationMarket Drivers for Gasification

Market DriversMarket Drivers

Fossil Fuel Prices

Market Drivers Fossil Fuel AvailabilityFossil Fuel Availability

Proven Technology

Types of Gasifiers

Major Types of Coal/Coke GasifiersMoving Bed Entrained Bed

TransportFluidized BedProduct

Gas,Ash

GasifierTop

TransportFluidized Bed

:

Coal,Sorbent or

Inert

TransportGasifier

Coal, Char Recycle, Gas

Steam,Oxygenor Air

Recycle DriveGas

GasifierBottom

0 500 1000 1500 2000 2500

Transport GasifierTransport Gasifier

Transport reactors  is reported to provide a low‐capital‐cost gasification system uses a state of the art pollution control systemgasification system uses a state‐of‐the‐art pollution control system 

It is has the following  advantagesg g

• High throughput and medium cold gas efficiency

• Simultaneous removal of sulphur

• More suitable for hydrogen /chemical production from syngas

So far the transport reactor gasifier has not been used in  commercial scale widely but it is gradually going to occupy its place in the commercial market as the KBR gasifierp g

Characteristics of Different Categories of Gasification Process (source : Simbeck coal

ifi i id b k 1993)Gasification Process  

Category Moving Bed Fluidized  Bed Entrained  Bed

Ash conditions Dry ash Slagging Dry ash Agglomerating Slagging

gasification guide book 1993)

Ash conditionsTypical processes

Feed

Dry ash            SlaggingLurgi                  BGL

Dry ash     AgglomeratingWinkler      KRW ,U GasHTW,CFB

SlaggingShell, Texeco,E Gas, Noell, KT

CharacteristicsSizeFinesacceptability

6‐50mm         6‐50 mmLimited        Better than 

dry ash

6‐10mm           6‐10 mmGood                  Better

< 100 umUnlimited

acceptabilityPreferred coal rankOperating Characteristics

dry ash  Any                 High Low                     Any Any

Outlet gas temp

Oxidant demandSteam demand

Low                  high‐‐‐‐‐(425‐650 o C)……High                  lowHigh low

…………Moderate ……….       ……..(900‐ 1050 oC)….……….moderate………..……….moderate………..

High1250‐1600 o C

highlowSteam demand

Other characteristics

High                  low…Hydrocarbons in gas…

……….moderate………..….lower carbon conv…..

lowPure gas , high carbon conv.

GasifiersGasifier Technology Typical process conditions Remarks

Fixed bed BGL, Lurgy dry ash

Combustion temp : 1300 oC(slurry feed), 1500‐1800 oC (dry

‐Suitable for high ashdry ash (slurry feed),  1500 1800 oC (dry 

feed) Gas outlet temp: 400 ‐550oC,   Pr.  0.15‐2.45 MPa , Res.Time ; 15‐30min. Feed particle size ; 0‐10mm

high ash content feed; 35%‐Syngas 

t i tcontains tar and phenolic compounds,     ‐more loss of fine particles

Fluidized bed HTW, KRW, Mitsui Babcock

Combustion temp : 900‐1200 oCGas outlet temp: 700 ‐900 oC,   Pr.  

In situ S capture when S 

0.1‐2.94 MPa , Res.Time ; 10‐100 s. Feed particle size ; 0.5‐5.0mm

< 2 wt %, suitable for low reactivity feeds like low ranklike low rank coal ,biomass, no tar, reduce loss of fines

GasifiersGasifier Technology Typical process conditions Remarks

Entrained bed BBP, Hitachi MHI

Combustion temp : 1500 oCGas outlet temp: 900 1400 oC

‐Syngas does not contain tarHitachi,MHI, 

Prenflo,SCGP,  E‐Gas & Texeco

Gas outlet temp: 900 1400 oC, Pr.  2.94‐3.43 MPa , Res.Time ; 1‐10 s. 

not contain tar ‐suitable for low reactivity feeds petcoke‐In situ S removal, no fines loss

T t KBR C b ti t 900 1050 C P tTransport Reactor

KBR Combustion temp :900‐1050 oCGas outlet temp: 590 ‐980 oC,  Pr.  0.29‐1.47 MPa ,,Res.Time ; 1‐10 s. 

Prevents exposure of raw coal to the oxidant ;preventing combustion of  volatile matter, only charonly char combustion,‐Not well proven

Gasifiers for PetCoke• Suitable gasifiers are entrained bed type• Very high temperature to provide good carbon conversion for this low

reactivity fuel• Heavy metals in petcoke can be encapsulated in glass-like slag

GE gasifier E-Gas

• Slurry feed type (GE, E-Gas) and dry feed type (Shell, Prenflow, Noell)

GE gasifier Shell/Prenflow/Noell(WHB) gasifier (quench) gasifier

:

Features of Entrained flow Processes

Process Stages Feed Flow Reactor wall

Syngas Cooling

Oxidant

Kopper‐Totzek

1 Dry Up Jacket  Syngas cooler( SC)

Oxygen

Shell SCGP 1 Dry Up Membrane Gas quench  Oxygen&  SC

Prenflo 1 Dry Up Membrane ‐do‐ Oxygen

Future  Energy (GSP)

1 Dry Down Membrane Water  quench or SC

Oxygen

GE (Texeco) 1 Slurry Down Refractory ‐do‐ OxygenGE (Texeco) 1 Slurry Down Refractory do Oxygen

E‐Gas 2 Slurry Up Refractory Two stage gasification

Oxygen

CCP (Japan) 2 Dry Up ‐ do‐ Air

Eagle 2 Dry Up Membrane ‐do‐ oxygen

Gasification - Feedstocks & ProductsGasifier Section:

Oxygen (95-99%)

N2

•Controlled chemical reaction•Typically > 1250 deg C•Up to 80 Kg/cm2

•Organics Destroyed

Air

g y•Short residence time (seconds)•Reduced O2 Environment

GProducts (syngas):CO Gas

Clean-UpBefore

ProductASU

•CO •H2

By-products:

CO/H2 ratio can be adjustedGasifier

(quench)

Carbonaceous materials:Coal, Petcoke, Petroleum

ProductUse!

By-products:•H2S •CO2

•Ash (slag)•Steam

, ,Residues etc. Quench Section:

•Gas and molten ash quenched in circulating water bathA h/ l di h d i t•Ash/slag discharged as inert, glassy frit (saleable product)

Slag (Inert Minerals/Ash

Entrained Flow Gasifier

• Entrained bed gasifiers have ability to  handle practically  any coal / petcoke as feedstock and to produce a clean,any coal / petcoke as feedstock and to produce a clean, tar free gas (ash is produced as inert slag)

• Oxygen consumption is high specially in case of coal –yg p g p ywater slurries or coals with high moisture content or ash content 

• These gasifiers , developed after 1950,  operate at 20 ‐70 bar pressure and at high temperatures of at least 1400oC

( carbon conversion > 99% )

• These gasifiers are now preferred for hard coals  and have been selected for  most of commercial sized IGCC applications

Optimizing process conditionsOptimizing process conditions

• Entrained flow gasifiers operating with dry coal feed  typically g p g y yp yhave temperatures of the order of 1500oC

• Oxygen consumption is high  under the conditions, still some d t i i dmoderator is required

• The challenge is to operate with close to minimum amount of gasifying agent ( reduces the requirement on expensive oxygen g y g g ( q p ygper unit product gas)

• If less oxygen is used, more steam is needed ( better as steam is h )cheaper)

• Optimization is done on basis of  gasification reactions of C with oxygen and steam ( C+1/2 O2 = CO & C+H2O = CO + H2)oxygen and steam ( C 1/2 O2  CO  &  C H2O   CO   H2)

Syngas ProcessingSyngas Processing

Syngas Cooling and Conditioning‐ steps

Reducing  syngas temperature

– Extract valuable energyExtract valuable energy  

– Permit use of more conventional materials

– Use conventional/commercial processes

Removal of  chemical species that 

– Foul, corrode, or erode system components

– Poison or deactivate chemical processing agents

– Are environmentally unacceptable for release

T t S itTarget Syngas purity

‐ H2S and COS concentration

‐ CO concentration‐ CO2 concentration

Adjustment of H2/CO ratio

Acid Gas (Sulphur) Processing( p ) g

CO2 Gas Compression CO22 Enrichment Compression

CO2

CO2

(Sequestration)

COSHydrolysis

AcidGas

RemovalClean Syngas

Raw Syngas

Gas

(Atmosphere)

(H2, CO, CO2, H2O, H2S, COS, and

trace

COS + H2O ⇔ CO2 + H2SGas

H2S GasEnrichment

SulfurRecovery

TailGas

T t ttrace contaminants)

sulfur

Enrichment Recovery Treatment

Full sulfur processing envelopeFull sulfur processing envelope

AGR Technologies(AGR - Acid Gas Removal)(AGR - Acid Gas Removal)

Major Technology Options:Clean

"Clean Syngas"CO, H2

Major Technology Options:• MDEA (methyldiethanolamine) – Chemical absorption,

98% to 99+% S removal, large CO2 slip (unless use a second stage for CO recovery) moderate operating

Solvent

second stage for CO2 recovery), moderate operating temperature, lowest AGR capital cost

• Selexol tm (primarily dimethyl ethers of polyethylene glycol, DEPE) – Physical absorption, 99+% S removal,glycol, DEPE) Physical absorption, 99 % S removal, variable CO2 slip (based on design), higher AGR cost than MDEA but overall AGR/SRU system costs similar

• Rectisol tm (methanol) - Physical absorption, 99.5% ( ) y p ,to 99.9+% S removal, complete CO2 removal possible, highest AGR cost, coldest operating temperatures

• Warm Syngas Cleanup - New technologies (e.g.,

Dirty Solvent

RTI/Eastman) being developed that operate at high temperatures (> 205-315 C) and at sub-ppm S levels"Dirty Syngas"

CO,H2,CO2,H2S

Compositional Conditioningp g

H2/CO adjustment is required for:

Hydrogen production

SNG production

Ammonia production

Methanol production,p ,

Water Gas Shift Reaction (WGS)

CO + H2O ⇔ CO2 + H22 2 2

CO shift operate with variety of catalysts between 200- 500oC. High temp (300-500oC) shift uses an iron oxide based catalyst promoted typically with Cr or Cu (sulphur tolerence-100 ppmv)promoted typically with Cr or Cu.(sulphur tolerence 100 ppmv)

Low temp shift 200-270oC uses a copper -zinc –aluminum catalyst. CO content is reduces to about 0.3 mol%

Contribution of Various Components on the Overall Construction Cost of IGCC

Process Description

Function Share of construction

costcostFeed-stock (coal) handling system

Receive, prepare and feeding of gasifier

12%

Gasifier, ASU & Syngas cooling

Gasify coal into syngas, produce pure oxygen steam for gasification process and cool raw gas

30%

process and cool raw gas

Gas clean up and piping

Remove particulates and gases from syngas

7%

Combined cycle Generate electricity with 33%Combined cycle power block

Generate electricity with syngas using CT and team turbine cycle

33%

Remaining Cooling water systems 18%Remaining components and control system etc

Cooling water systems, spent ash and sorbent handling, controls and structures

18%

Syngas Utilization:

P d ti f PProduction of Power Hydrogen, Chemicals /Hydrogen, Chemicals /

Fuels

What can you do withWhat can you do with CO and H2 ?

Syngas

FuelGas/

IronReduction

Gas/SNG

Transportation/ Aviation Fuels

Building Blocks for Chemicals

Clean Electricity

Aviation Fuels& Fertilizers

Downstream Utilization of Syngas

- Power Generation

- Hydrogen production

- FT / Chemicals

Poly‐generation with GasificationPower

ElectricitySteam

Power

FuelsFischer-Tropsch Diesel

NaphthaSyngas

pMethanol/Ethanol

Dimethyl Ether and

Hydrogen

ChemicalsWaxes

Coke/Coal

OlefinsAcetates and many

Others

Desired Quality of the treated Syngas for various Downstream Applicationsfor various Downstream Applications

Downstream Sulfur CO2 (Vol.%) COuse (wppm)

2 ( )

Power 10-15 Maximize -

Hydro- <1 <0.1 < 50 yprocessing wppm

Chemical <0.01 0.05 – 2.0 H2/CO 2control

Power Generation

GasifierGas

CleanupCombined

CycleRawGas

CleanG

Residue/Coke/ Powerp CycleGas GasCoal

High efficiency: due to CC

Potential for even higher efficiency: advanced GT

GHG reduction: by high efficiency & easy CO2 removal

Low SOx and NOx : H2S vs SO2, GT has low NOx

:

Low water consumption: 2/3 power from GT

Hydrogen Production

Key Processes

Syngas generation

Water gas shiftWater gas shift 

Desulfurization

H d ifi iHydrogen purification

– CO2 removal

Fi l li hi– Final polishing

Hydrogen PurificationPressure swing adsorption (PSA)Pressure swing adsorption (PSA)– Solid molecular sieve adsorbents

– Regenerated by pressure swing

d– Hydrogen purities >99.99%

– Hydrogen recovery > 90%

MembranesMembranes– Partial pressure separation by polymer membranes

– Effective for recovery dilute H2 from process streams

– Low pressure hydrogen productCryogenic Separations

• Low temperature (-130 to -155ºC) phase separation

• Poor operation in the presence of acid gases

Plugging

H O CO and H SH2O, CO2, and H2S

FT SynthesisFT Synthesis

FT is making a “comeback” in a big wayFT is making a “comeback” in a big way

Hi h C t ( l h f ) di l / th Hi h C t ( l h f ) di l / th High Cetane ( sulphur free) diesel / other High Cetane ( sulphur free) diesel / other

chemicalschemicals

Key Issues

Improving economicsImproving economics

Key IssuesFT Reactor

Catalyst

FT ReactorsFT ReactorsFixed Fixed Fixed Fixed FluidizedFluidizedSlurrySlurrySlurrySlurrySlurry reactors are generally cheaper and more Slurry reactors are generally cheaper and more flexibleflexible

CatalystsIron or cobalt basedIron or cobalt basedIron is fuel flexible; cobalt limited to natural gas

All of the proposed gas to liquids (GTL) plants will use cobalt because it is better suited for high H2/CO ratio  syngas

Gasification of Indian coal

Indian Coal / Petcoke characteristicsIndian Coal / Petcoke characteristics

Indian Coals in general :g• Have high ash content up to 40 %• Are highly reactive

Hi h h t t li it it it bilit f ifi tiHigh ash content limits it suitability for gasification

Petcoke on the contrary:Petcoke on the contrary:• Have very low ash content• Are not highly reactive

Combination of Coal with Petcoke forms a balanced feed for Gasifier

Change of Feed Property with the Mixing of Coal and PetcokeMixing of Coal and Petcoke

Coal Pet coke Mixed feedMoisture 11.8 7.00 9.40Ash(%w) 41.10 0.26 20.68( )C (%w) 36.27 82.21 59.21H (%w) 2.48 3.11 2.80H (%w) 2.48 3.11 2.80N (%w) 0.81 1.90 1.36O (%w) 6 62 0 02 3 32O (%w) 6.62 0.02 3.32S (%w) 0.93 5.50 3.21

LHV (MJ/k ) 13 10 31 99 22 55LHV (MJ/kg) 13.10 31.99 22.55

Some Commercial IGCC Plants based on Pet. Coke /CoalPlant NamePlant Name TechnologyTechnology Feedstocks Feedstocks ProductsProducts Year Year gygyMarifu IGCC Marifu IGCC plant, Japanplant, Japan

TexacoTexaco Pet cokePet coke Electricity Electricity 20042004

Puertollano IGCC Puertollano IGCC PRENFLOPRENFLO Coal and pet cokeCoal and pet coke Electricity (310 Electricity (310 19971997Puertollano IGCC Puertollano IGCC plant, Spainplant, Spain

PRENFLOPRENFLO Coal and pet cokeCoal and pet coke Electricity (310 Electricity (310 MW)MW)

19971997

Wabassh River Wabassh River Energy Ltd., USAEnergy Ltd., USA

EE--GAS GAS (Destec/Dow)(Destec/Dow)

Pet cokePet coke Electricity (262 Electricity (262 MW)MW)

19951995Energy Ltd., USAEnergy Ltd., USA (Destec/Dow)(Destec/Dow) MW)MW)

Delaware clean Delaware clean energy Cogen. energy Cogen. Project, USAProject, USA

TexacoTexaco Fluid pet cokeFluid pet coke Electricity and Electricity and steamsteam

20012001

Project, USAProject, USAEl Dorado IGCC El Dorado IGCC Plant, USAPlant, USA

TexacoTexaco Pet coke, Ref. Pet coke, Ref. Waste and Nat. gasWaste and Nat. gas

Electricity and HP Electricity and HP steamsteam

19961996

D k l (D k l ( Sh llSh ll Bit C lBit C l El t i it ( 253El t i it ( 253 19941994Demkolec (now Demkolec (now Nuon) Buggenum Nuon) Buggenum NetherlandsNetherlands

ShellShell Bit. CoalBit. Coal Electricity ( 253 Electricity ( 253 MW)MW)

19941994

Tampa ElectricTampa Electric EE--GasGas Coal/CokeCoal/Coke Electricity (250Electricity (250 19961996Tampa Electric Tampa Electric Polk power Polk power station, USAstation, USA

EE--GasGas Coal/CokeCoal/Coke Electricity (250 Electricity (250 MW), steamMW), steam

19961996

Coal based Gasification plants

GasifierGasifier ProjectProject

TexacoTexaco 1,300 1,300 tpdtpd Tennessee Eastman coal to chemicals, 1983, USATennessee Eastman coal to chemicals, 1983, USA1,000 1,000 tpdtpd LunanLunan coal to ammonia in Chinacoal to ammonia in China1,000 1,000 tpdtpd LunanLunan coal to ammonia in Chinacoal to ammonia in China900 900 tpdtpd Ube coal to ammonia in JapanUbe coal to ammonia in Japan

ShellShell 900 tpd coal to chemicals at yingcheng, China (2004 startup)900 tpd coal to chemicals at yingcheng, China (2004 startup)p y g g ( p)p y g g ( p)2,000 tpd coal for ammonia/ urea at Donting, China (2004 2,000 tpd coal for ammonia/ urea at Donting, China (2004 startup)startup)1,200 tpd coal for chemical at Liuzhou, China (2005 startup)1,200 tpd coal for chemical at Liuzhou, China (2005 startup)2,000 tpd coal for chemical at Heibei, China (2005 startup) 2,000 tpd coal for chemical at Heibei, China (2005 startup)

LurgiLurgi 16,800 tpd lignite to SNG in North Dakota, 198416,800 tpd lignite to SNG in North Dakota, 1984gg , p g ,, p g ,100,000 tpd coal to liquid fuels and chemicals in South Africa, 100,000 tpd coal to liquid fuels and chemicals in South Africa,

UU--GasGas 800 tpd Wujing trigeneration plant in Shanghai 800 tpd Wujing trigeneration plant in Shanghai

BGLBGL 540 MW IGCC in Kentucky (2009 startup)540 MW IGCC in Kentucky (2009 startup)541 MW IGCC in Ohio (2009 startup)541 MW IGCC in Ohio (2009 startup)

Gasification DevelopmentsGasification‐ Developments

Gasification DevelopmentsGasification  Developments

• Synthetic fuels have been produced from coal gasification using Fisher‐Tropsch technology on a commercial scale in South Africa since 1950s

l f h i f l h b• More recently syngas for synthetic fuels has been generated by partial oxidation of natural gas and a number of gas to liquids (GTL) projects are under waynumber of gas‐to ‐liquids (GTL) projects are under way

• IGCC application is also gaining increasing attention 

• This technology is allowing coal conversion to electric• This technology is allowing coal conversion to electric power at high efficiencies and  greater emissions reductionreduction

Gasification ‐Developments

• Modern day gasification units are mostly based on i t t d ifi ti bi d l (IGCC) dintegrated gasification combined cycle (IGCC) and produce electricity along with  hydrogen/methanol/FT liquid fuels / chemicals / synthetic natural gas or anyliquid fuels  / chemicals / synthetic natural gas  or any combinations of thes

• This concept of poly‐generation is  infusing high research interest as it reduces the emissions  as well as  improves te est as t educes t e e ss o s as e as p o esthe plant economy 

Gasification –Developments..contd.Gasification  Developments..contd.

• Some recent developments in gasification So e ece t de e op e ts gas cat otechnology are catalytic  steam gasification and plasma gasification

• In catalytic steam  gasification a hydrogen/ methane rich gas stream is produced under mild, 

t h i ditinear atmospheric conditions  • Normally some alkali and alkaline earth catalysts are usedare used

• Addition of alkali metal catalysts enables steam gasification to proceed at lower temperaturegasification to proceed at lower temperature

Synthetic Natural Gas(SNG) from SyngasSynthetic Natural Gas(SNG) from Syngas

• One plant already operating at Dacota and two otherOne plant already operating at Dacota  and two other proposed

• Make Syngas from coal and catalytically converted to y g y yMethane – an expensive option

• Great Point Energy company of USA has developed( in gy p y p2009)  a catalyst based gasification process – direct methane and hydrogen are obtained as product ( using 

l )proprietary catalyst)

Synthetic Natural Gas(SNG) from SyngasSynthetic Natural Gas(SNG) from Syngas

• 13000 to 14000 cubic meters of N/G produced at its13000 to 14000 cubic meters of N/G  produced at its pilot plant

• Company claims the technology  more economical/ p y gy /reliable than drilling for new  natural gas or importing LNG

Cheaper Natural Gas from CoalCheaper Natural Gas from Coal http://www.technologyreview.in/business/18119/ 

Plasma GasifierPlasma Gasifier

• In plasma gasification ,fuel or waste is  fed to a reactor vessel h l t i ll t d l t t t f b twhere electrically generated plasma at a temperature of  about 

20,000 °C  is present

• Under the conditions  the fuel or waste is heated to a very  high temperature(>2000 °C), which causes the organic compounds in  h f l di i i i l l l hthe fuel or waste to dissociate into very simple molecules such as   hydrogen, carbon monoxide, carbon dioxide, water vapour and  methane

• These simple gas molecules are allowed to continuously  flow f h l d lfrom the reactor to gas cooling and cleaning equipment 

Plasma GasifierPlasma Gasifier

• Ash and  other inorganic materials  present in fuel or wastes are melted down to a complex liquid silicate that flow to theare melted down to  a complex liquid silicate that flow  to the bottom of the reaction vessel

• Gas composition coming out of a plasma gasifier is lower in• Gas composition coming out of a plasma gasifier is lower in trace  contaminants than with any kind of incinerator or other gasifier

• This  type of gasifier can use wastes containing high amount of moisture(M i hi h f i i i d(Moisture which consumes energy for its vaporization and affects the   economics but does not affect the process) 

Plasma GasifierPlasma Gasifier

Emerging TechnologiesEmerging Technologies

Technological developments are on following lines: 

• Elimination of Air Separation Unit (ASU)

• Low rank, high‐ash, high‐moisture coal  , g , g

compatible

• High Temperature Syngas Clean up• High Temperature Syngas Clean up

• Higher efficiency 

• Lower cost

Large scale up of the technology required, by a f f 30factor of ~30

Gasification ‐ Developments

/ l S ll i lLarge / Mega plants  Vs  Smaller capacity plants

Investing in EnergyInvesting in Energy

• Chemical & Power plants are run for longer period;Chemical & Power plants are run for longer period; say 50 years or more typically

• Investment in such projects is made based on p jfollowing considerations

‐ To ensure that the plant remains competitivep p

for that period

‐ Adaptability  to changing business ,   p y g g ,

environment etc.

Current Approach to Chemical ProcessesCurrent Approach to Chemical Processes

• Currently approach is to build mega / large plantsCurrently approach is to build mega / large plants with higher efficiencies

• Rely on economy of scale for better economicsy y

Constraints in Larger PlantsConstraints in Larger Plants

• Requirement of large capital investment

• Design generally quite conservative ( not trying newDesign generally quite conservative ( not trying new concepts)

• Not easily adaptable to changing businessNot easily adaptable  to changing business

Implications for long term Viability of lLarge Plants

• Plants meet today’s emission normsPlants meet today s emission norms

• Limits of CO2 emissions in next 50 years can be expected to be significantly reduced‐ will the plant p g y pbe managed then !   

Is bigger always better ?

New ApproachNew Approach

• A new approach is to build smaller modular plantsA new approach is to build smaller modular plants with advantages of

‐ lesser investment

‐ higher flexibility

‐ faster implementationfaster implementation

‐ returns on investment much faster

• New Ideas can be incorporated in later modules forNew Ideas can be incorporated in later modules for efficiency improvement

• Risks management can be done effectivelyRisks management can be done effectively 

Developments in Syngas p y gCleanup & F T Process

Syngas cleanup ‐d i ( )Adsorption (warm process) 

• Some adsorbents like ZnO/CuO, Cr2O3, Al2O3 etc. can adsorb acid t I f h d ti H S igas components. In case of such adsorption processes, H2S is 

converted to metal sulphides typically in  the temperature range of 315–530 °C, which produce SO2 during  regeneration through oxidation at 590–680 °C 

• Reactions for the   conversion of sulfur in the above processes using ZnO as adsorbent are:using ZnO as adsorbent  are:  

Desulfurization  

ZnO + H2S→ZnS +H2OZnO  H2S→ZnS   H2O 

Regeneration

ZnS + 2O2→ZnO + SO2 

Syngas cleanup ‐Adsorption (warm process) 

• These metal oxides also adsorb CO2These metal oxides also adsorb CO2

• Research Triangle Institute (RTI) International USAResearch Triangle Institute (RTI) International, USA has developed   zinc titanate sorbent technology for desulfurization of syngas y g

• In addition, RTI has also developed the direct sulphur , p precovery process (DSRP) stream

Direct Sulphur Recovery Process(DSRP)(DSRP)

• The DSRP unit consists of essentially two fixed bedThe DSRP unit consists of essentially two fixed bed catalytic reactors and a condenser follows each reactor

• Approximately 95% of sulphur in the inlet stream of pp y pthe first reactor is converted to elemental sulphur

• Outlet gas of the first DSRP reactor is  cooled for removing sulphur as condensate

Direct Sulphur Recovery Process( )(DSRP)

• The cooled gas is passed to the second DSRP reactor e coo ed gas s passed o e seco d S eac owhere 80–90% of the remaining  sulphur compounds are converted to elemental sulphur at 400 °C by high pressure Cl iClaus reaction

T t l ffi i f th t t f th i f• Total efficiency of the two reactors for the conversion of sulphur compounds to elemental sulphur is about 99.5%

• By using tail gas treatment (TGT) units, even higher sulphur  recovery, up to 99.8%, can be madep y, p ,

Catalysts for F T  Process

Fischer Tropsch Synthesis• Co – Wax and middle distillatesCo  Wax and middle  distillates  • Fe  ‐ Gasoline;• Cu & K added, Cu increases mol wt of HC;Cu & K added, Cu increases mol wt of HC;• Supported Co preferred due to its lower WGS 

activity & consequent lower loss of C as CO2y q 2

Product Work up• Wax Conversion to diesel and gasolineg• Mild Hydro‐cracking/ Isomerization  catalysts( Pt 

metal‐ acidic oxide support )

74

pp )

Syngas to Power and FT FuelsSyngas to Power and FT Fuels

This scheme allows following options:•A peak demand can reduce conversion on the F T reactors and produce more electricity•A low demand can increase fuel production and drop electricity demand

Fisher Tropsch ProcessFisher Tropsch Process 

• A Fisher ‐Tropsch Process produces high pressureA Fisher  Tropsch Process produces high pressure stream

• It must be converted into electricity otherwise the ypotential will be lost

‐ This effectively increases the energy produced from y gy pthe process without increasing the CO2 emissions

Power and fuels from Coal / PetCoke GasificationTexaco EECP Project: Topics Catalysis 26 (2003)13Texaco EECP Project: Topics Catalysis, 26 (2003)13

Feed : 1235 TPD of PetCoke

PC ⇒ SG ⇒ 75% in Power Plant

⇒ 25%  in FT fuel (tail gas ⇒Power)( g )• 55 MW Electricity; Steam

• 20 TPD diesel; 4 TPD Naphtha• 20 TPD diesel; 4 TPD Naphtha

• 82 TPD Wax(⇒60 TPD diesel); 89 TPD Sulphur; • H2: CO = 0.67

• Once‐thru slurry(Fe) FT reactor

77

y( )

About 10 % better Economics of the plant reported

SUMMARYSUMMARY

Gasification process   completely converts  coal / petroleum residues into more l dd d d tvalue added products

Gasification based energy systems/IGCC are becoming stable , affordable for high‐efficiency energy supply with a minimal environmental impact

Feedstock Flexibility – utilization of low‐cost available feedstocks (petroleum 

coke, biomass, municipal and industrial waste, and coal)

Petcoke / Coal mixture is considered a better feedstock as it balances some 

negative aspect of each other 

Higher product flexibility ; electricity, fuels, chemicals, hydrogen, and steam

The most economical technology for CO2 capture

Serious R & D efforts are  being made to make the gasification/ IGCC  

technology more reliable & cost effectivegy