CARBON BALANCE EVALUATION IN SUGARCANE BIOREFINERIES IN ... · Carbon Balance Evaluation in...

CARBON BALANCE EVALUATION IN SUGARCANE BIOREFINERIES

IN BRAZIL FOR CARBON CAPTURE AND UTILISATION

PURPOSES

Neo-Carbon 4th Researchers’ SeminarOctober 19-20, 2015

Larissa de Souza Noel Simas Barbosa, USP/VTTEemeli Hytönen, VTT

Pasi Vainikka, VTT

Carbon Balance Evaluation in Sugarcane Biorefineries in BrazilLarissa Noel [email protected]

• Motivation

• Brazilian Sugarcane Biorefineries

• Objective

• Considered Scenarios

• Results

• Conclusions

• Appendix

Agenda


• In order to limit the global warming to +2°C, a zero emission energy system has to be launched by 2050

• Yet, carbon is most probably needed for fuels, chemicals, and materials: Sustainable source of carbon in non-fossil energy system.

• Sugarcane biorefineries produce a large amount of CO2 as a by-product of their conversion techniques

• The biggest challenge for the future of bioenergy is to increase the energy yield per same unit of land

• Opportunity to convert a liability into an asset leading sugarcane industry to a negative carbon cycle

• One more product is produced: Synthetic Fuels and Chemicals from CO2 such as Natural Gas (SNG)

Motivation


• Sugarcane production: one of the most important economic activities in Brazil.

• Sugarcane Biorefineries: evolved from a single product industry (sugar) to a polygeneration plant(sugar, ethanol and electricity).

• Global Ethanol Production in 2013:

Global: 87.2 billion L = 522 TWhBrazil: 23.2 billion L = 139 TWh

Brazilian Sugarcane Biorefineries



• Biofuel industry in Brazil: expected to expand:- Increase the capacity of 1G ethanol industry.- Introduce 2G ethanol – Biomass Residues used for industrial

purposes.

• 2G Ethanol: Lignocellulosic Residues as feedstock for bioethanolproduction

StrawStalksBagasse



Hypothesis:

Most of the carbon harvested from the field is actually converted to CO2.

Large source of renewable CO2 available: can be converted into value-added products with (renewable) electricity.


Objective

• Establish the carbon balance and CO2 flows for current and futuresugarcane mill configuration

• Propose carbon capture utilization concept that is able to increasesugarcane energy productivity per hectare

• Determine the role of CO2 in the future energy system such as theone showed for South America 100% RE power supply [1]

[1]: Barbosa L.S.N.S., Bogdanov D., Vainikka P., Breyer C., Complementarity of hydro, wind and solar power as a base for 100% RE energysupply: South America as an example, Rio 15 World Climate & Energy Event, Rio de Janeiro, 04.09.2015


Scenarios for a typical 2 Mtcane/a mill

S-I: Current Scenario• Ethanol, Heat and Electricity production• 100% of bagasse for bioelectricity/heat production

S-II: Current + Scenario – Highest (Surplus) Electricity Production• Ethanol, Heat and additional Electricity production • 100% of bagasse for bioelectricity/heat production• 34% of straw for bioelectricity production

S-III: Future Scenario – Integrated 1G2G plant• Ethanol, Heat and Electricity production • Bagasse: 72% Used for 2G ethanol and 28% for

bioelectricity/heat• Straw: 28% for 2G ethanol and 22% for bioelectricity/heat

production• Lignin and Biogas: Are used for bioelectricity/heat production


Results – Carbon Mass Balance S-I

Key observations• Only 17% from the carbon

available end up in the final product

• 63% from the carbon entering the mill form CO2


Results – Carbon Mass Balance S-II

Key observations• Only 17% from the carbon




Results – Carbon Mass Balance S-III

Key observations• 22% from the carbon



– 23% of the CO2 comes from fermentation


• Most of the sugarcane carbon is converted into CO2 in all the considered scenarios

• All the considered scenarios represent an opportunity for the use of biogenic CO2 for carbon capture and utilisation purposes

• Electricity surplus of sugarcane biorefineries: LP steam can beextacted from the turbine and used for post-combustion CO2 cleaning process

Results – CO2 flow and energy ouputsFor a typical 2 Mtcane/a mill

Results/Scenario S-I S-II S-IIICO2 from fermentation (t/h) 30 30 40CO2 from combustion (t/h) 112 154 126Surplus Electricity (MWe) 41.1 71.6 21.9


Results – CO2 from combustion is captured

Post-combustion amine-based (MEA) absorption of CO2:

• Effective for dilute CO2 streams (Bagasse combustion 12% of CO2)

• Amine-based CO2 capture systems are a proven technology commercially available today

• Major R&D effort to improve the process especially regarding the fate impurities

Diagram source: Cau G., Tola V., Deiana P. Comparative performance assessment of USC and IGCC power plants integrated with CO2 capture systems. Fuel 2014, 166:820-833


Results – CO2 from combustion is captured

Typical bagasse exhausted gases composition:

• Problem: CO2 stream in the synthesis should be practically pollutant free

• To what extent it is economically feasible to clean the combustion gases and CO2?

• There are technologies available for sufficient cleaning

• High NOx concentration: NOx reduction equipment will favor the absorption: SNCR, SCR or wet scrubbing with additives are some options

• Heat Stable Salts (HSS) can degrade the absorbent

Component ValueCO2 12 %VolH2O 28%VolO2 3 %VolN2 57 %Vol

PollutantsParticle matter 93 mg/scbmCO 116 mg/scbmNOx 442 mg/scbmSOx 23 mg/Nm3HCl 8 mg/Nm3THC 12 mg/Nm3HF 0.04 mg/Nm3Dioxins and Furans 0.01 ng/Nm3


Results – CO2 from combustion is captured: MEA Absorption

MEA absorption results:

• MEA concentration in sorbent (wt%): 30%

• CO2 capture efficiency: 90% 100.7 t CO2 /h captured

• Total MEA flow rate: 21.21 kmol/s (L/G = 3.45)

• Total solvent regeneration heat requirement: 124 MWth

• Total electricity consumption of MEA absorption process (blower + pump + CO2 compressor): 12.3 MWe

• CO2 purity: 99.5%

Model used: Details of a Technical, Economic and Environmental Assessment of Amine-Based CO2 capture Technology for Power Plant Greenhouse Gas Control, National Energy Technology Laboratory, 2002


Renewable Energy Potential in Brazil

• Low LCOE for solar PV (optimal titled) in the entire country

• Low LCOE for wind in the NE coast and South

• High availability of RE sources with low seasonal variability

For 2030• PV CAPEX: 550 €/kW

OPEX: 8€/kW• Wind CAPEX: 1000 €/kW

OPEX: 20€/kW

Source: Barbosa L.S.N.S., Bogdanov D., Vainikka P., Breyer C., Complementarity of hydro, wind and solar power as a base for 100% RE energy supply: South America as an example, Rio 15 World Climate & Energy Event, Rio de Janeiro, 04.09.2015


927

2036

2963

0

1000

2000

3000

4000

Ethanol Biomethane Ethanol +Biomethane

Ener

gy (G

Wh/

a)

S-I

Results – CO2 from combustion is captured: Power-to-GasPower-to-Gas system:

• In one year S-I ethanol biorefinery produces:

– 927 GWh of Ethanol– 2036 GWh of Methane

Process Input Output

Electrolysis* Electricity (MWe) 995 H2 (t/h) 1.4Water (t/h) 12.8 O2 (t/h) 11.3

Methanation** Syngas - LHV (MWth) 617 Methane – LHV (MWth) 508Electricity (MWe) 0.6 Steam (500°C, 94 bar) (MWth) 103

*Electrolysis efficiency (LHV): 62%**Methanation efficiency (LHV): 82%. TREMP high temperature process was considered

x 3

3 times more energy/ton of sugar cane

Reduction on the emission of 403 mi tons of CO2/year

Model used: Hannula, I. Co-production of synthetic fuels and district heat from biomass residues, carbon dioxide and electricity: Performance and cost analysis. Biomass and Bioenergy 2015,74:26-46


33.8

12.3

21.5

0Total Ethanol Mill

SurplusMEA Requirements Final Net Ethanol Mill

Elec

tric

ity (M

We)

Electricity Balance**

64

60 124

0Ethanol Mill Methanation MEA Requirements

Heat

(MW

th)

Heat Balance*

Results – CO2 from combustion is captured: Steam and Electricity Balance

LP steam and electricity from the mill + steam from methanation> steam and electricity MEA requirements

* Superheated steam from methanation is able to supply at least 48% of MEA steam requirements (total steam available from methanation = 103 MW th). LP steam can be extracted from ethanol mill due to electricity surplus** Even after LP steam extraction, there is still electricity surplus from ethanol mill (21.5 MWe)


12073.3%

2616.0%

42.2%

31.8% 11

6.7%

Natural Gas Demand in Brazil (TWh), 2012 (IEA)

Industrial

Transportation

Residential

Commercial andPublic servicesOthers

Results – CO2 from combustion is captured: NG demand in Brazil

444 sugarcane mills in Brazil – 653 million tons of sugarcane produced in 2014 (UNICA)

• If CO2 from bagasse combustion is captured and used to produceSNG: 665 TWh of SNG would be produced/year

• In 2012, 164 TWh of NG demand

• PtG would produce 4 times 2012 Brazil’s demand for NG

• Sidenote: energy use in Brazilian transport sector 965 TWh

Sources: UNICA - www.unica.com.br/IEA - www.iea.org/statistics/statisticssearch/


Conclusions

• For all the studied scenarios sugarcane carbon is mainly converted into CO2 : S-I: 41%, S-II: 53%, S-III: 47%

• Nowadays, this CO2 is vented in the air and do not have positive impacts on efforts towards carbon management

• This carbon volume provides an interesting platform to increase the energy bounded to the same amount of carbon harvested from sugarcane fields

• Sugarcane biorefineries would have negative carbon emissions and contribute for GHG mitigation

• PtG technologies can supply 665 TWh/a of synthetic natural gas, whatcorresponds to 4 times of 2012 Brazil’s demand (164 TWh/a)

• Here SNG was considered, diesel, petrol, kerosene (FT), methanol are equally possible end products


Appendix

Parameters used for mass flow calculations in 1G and 1G2G integrated biorefineries:

Parameter ValueSugarcane processed (wet basis) 500 TC/hDays of operation 167 days/yearBagasse production (dry basis) 140 kg/TCStraw production (dry basis) 140 kg/TCFraction of straw recovered from the field 50%Medium Sucrose content in sugarcane juice (wet basis) 13.9 %Bagasse moisture content 50%Straw moisture content 25%Juice extraction efficiency 96%Ethanol yield 89%Cellulose content in bagasse/straw (dry basis) 42.0 %Hemicellulose content in bagasse/straw (dry basis) 30.3 %Lignin content in bagasse/straw (dry basis) 20.8 %Extractives content in bagasse/straw (dry basis) 4.8 %Ash content in bagasse/straw (dry basis) 2.9 %Maximum sugarcane straw for boilers 27%Fraction of bagasse for start-ups of the plant 5%Filter cake production 40 kg/TCFilter cake sucrose content (wet basis) 1.6%Filter cake moisture 70.0%Electric power demand 1G 30 kWh/TCElectric power demand integrated 1G2G 51 kWh/TCSteam consumption 1G 500 kg/TC


Appendix

Total installed capacity added in Brazil:


Appendix

Total installed capacity in Brazil:

NEO-CARBON Energy project is one of the Tekes strategy research openingsand the project is carried out in cooperation with Technical Research Centre of

Finland VTT Ltd, Lappeenranta University of Technology LUT and University of Turku, Finland Futures Research Centre.

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