CARBON BALANCE EVALUATION IN SUGARCANE BIOREFINERIES IN BRAZIL FOR CARBON CAPTURE AND UTILISATION PURPOSES

Transcription

1 CARBON BALANCE EVALUATION IN SUGARCANE BIOREFINERIES IN BRAZIL FOR CARBON CAPTURE AND UTILISATION PURPOSES Larissa de Souza Noel Simas Barbosa, USP/VTT Neo-Carbon 4 th Researchers Seminar October 19-20, 2015 Eemeli Hytönen, VTT Pasi Vainikka, VTT

2 Agenda Motivation Brazilian Sugarcane Biorefineries Objective Considered Scenarios Results Conclusions Appendix 2

3 Motivation 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 CO 2 as a byproduct 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 CO 2 such as Natural Gas (SNG) 3

4 Brazilian Sugarcane Biorefineries 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 TWh Brazil: 23.2 billion L = 139 TWh 4

5 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 bioethanol production Bagasse Stalks Straw 5

6 Brazilian Sugarcane Biorefineries Hypothesis: Most of the carbon harvested from the field is actually converted to CO 2. Large source of renewable CO 2 available: can be converted into valueadded products with (renewable) electricity. 6

7 Objective Establish the carbon balance and CO 2 flows for current and future sugarcane mill configuration Propose carbon capture utilization concept that is able to increase sugarcane energy productivity per hectare Determine the role of CO 2 in the future energy system such as the one showed for South America 100% RE power supply [1] 7 Carbon [1]: Barbosa Balance L.S.N.S., Evaluation Bogdanov in Sugarcane D., Vainikka Biorefineries P., Breyer in C., Brazil Complementarity of hydro, wind and solar power as a base for 100% RE energy Larissa supply: Noel South larissa.noel@usp.br America as an example, Rio 15 World Climate & Energy Event, Rio de Janeiro,

8 Scenarios for a typical 2 Mt cane /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 8

9 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 CO 2 9

10 Results Carbon Mass Balance S-II Key observations Only 17% from the carbon available end up in the final product 69% from the carbon entering the mill form CO 2 10

11 Results Carbon Mass Balance S-III Key observations 22% from the carbon available end up in the final product 57% from the carbon entering the mill form CO % of the CO2 comes from fermentation Larissa Noel

12 Results CO 2 flow and energy ouputs For a typical 2 Mt cane /a mill Results/Scenario S-I S-II S-III CO2 from fermentation (t/h) CO2 from combustion (t/h) Surplus Electricity (MWe) Most of the sugarcane carbon is converted into CO 2 in all the considered scenarios All the considered scenarios represent an opportunity for the use of biogenic CO 2 for carbon capture and utilisation purposes Electricity surplus of sugarcane biorefineries: LP steam can be extacted from the turbine and used for post-combustion CO 2 cleaning process 12

13 Results CO 2 from combustion is captured Post-combustion amine-based (MEA) absorption of CO 2 : Effective for dilute CO 2 streams (Bagasse combustion 12% of CO 2 ) Amine-based CO 2 capture systems are a proven technology commercially available today Major R&D effort to improve the process especially regarding the fate impurities 13 Carbon DiagramBalance source: Evaluation Cau G., Tola in Sugarcane V., Deiana P. Biorefineries Comparative in performance Brazil assessment of USC and IGCC power plants integrated with CO2 Larissa capture Noel systems. larissa.noel@usp.br Fuel 2014, 166:

14 Results CO 2 from combustion is captured Typical bagasse exhausted gases composition: Component CO2 H2O O2 N2 Value 12 %Vol 28%Vol 3 %Vol 57 %Vol Pollutants Particle matter 93 mg/scbm CO 116 mg/scbm NOx 442 mg/scbm SOx 23 mg/nm3 HCl 8 mg/nm3 THC 12 mg/nm3 HF 0.04 mg/nm3 Dioxins and Furans 0.01 ng/nm3 Problem: CO 2 stream in the synthesis should be practically pollutant free To what extent it is economically feasible to clean the combustion gases and CO 2? 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 14

15 Results CO 2 from combustion is captured: MEA Absorption MEA absorption results: MEA concentration in sorbent (wt%): 30% CO 2 capture efficiency: 90% t CO 2 /h captured Total MEA flow rate: kmol/s (L/G = 3.45) Total solvent regeneration heat requirement: 124 MW th Total electricity consumption of MEA absorption process (blower + pump + CO 2 compressor): 12.3 MW e CO 2 purity: 99.5% 15 Carbon Model used: Balance Details Evaluation of a Technical, in Sugarcane Economic Biorefineries and Environmental in Brazil Assessment of Amine-Based CO2 capture Technology for Power Larissa Plant Greenhouse Noel larissa.noel@usp.br Gas Control, National Energy Technology Laboratory, 2002

16 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 16 Carbon Source: Balance BarbosaEvaluation L.S.N.S., Bogdanov in Sugarcane D., Vainikka Biorefineries P., Breyer in Brazil C., Complementarity of hydro, wind and solar power as a base for 100% RE Larissa energy Noel supply: larissa.noel@usp.br South America as an example, Rio 15 World Climate & Energy Event, Rio de Janeiro,

17 Results CO 2 from combustion is captured: Power-to-Gas Power-to-Gas system: Process Input Output Electrolysis* Electricity (MWe) Water (t/h) H 2 (t/h) O 2 (t/h) Methanation** Syngas - LHV (MWth) 617 Methane LHV (MWth) 508 Electricity (MWe) 0.6 Steam (500 C, 94 bar) (MWth) 103 *Electrolysis efficiency (LHV): 62% **Methanation efficiency (LHV): 82%. TREMP high temperature process was considered 17 In one year S-I ethanol biorefinery produces: 927 GWh of Ethanol 2036 GWh of Methane 3 times more energy/ton of sugar cane Reduction on the emission of 403 mi tons of CO 2 /year Carbon Model used: Balance Hannula, Evaluation I. Co-production in Sugarcane of Biorefineries synthetic fuels in Brazil and district heat from biomass residues, carbon dioxide and electricity: Larissa Performance Noel and larissa.noel@usp.br cost analysis. Biomass and Bioenergy 2015,74:26-46 Energy (GWh/a) x 3 S-I Ethanol Biomethane Ethanol + Biomethane

18 Results CO 2 from combustion is captured: Steam and Electricity Balance LP steam and electricity from the mill + steam from methanation > steam and electricity MEA requirements Heat Balance* Electricity Balance** Heat (MWth) Electricity (MWe) Ethanol Mill Methanation MEA Requirements 0 Total Ethanol Mill Surplus 12.3 MEA Requirements Final Net Ethanol Mill * 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 MW e ) 18

19 Results CO 2 from combustion is captured: NG demand in Brazil 444 sugarcane mills in Brazil 653 million tons of sugarcane produced in 2014 (UNICA) If CO 2 from bagasse combustion is captured and used to produce SNG: 665 TWh of SNG would be produced/year Industrial Natural Gas Demand in Brazil (TWh), 2012 (IEA) Transportation Residential Commercial and Public services Others 4 2.2% 3 1.8% % % % 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 19 Sources: UNICA - IEA -

20 Conclusions For all the studied scenarios sugarcane carbon is mainly converted into CO 2 : S-I: 41%, S-II: 53%, S-III: 47% Nowadays, this CO 2 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, what corresponds 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 20

21 Appendix Parameters used for mass flow calculations in 1G and 1G2G integrated biorefineries: Parameter Value Sugarcane processed (wet basis) 500 TC/h Days of operation 167 days/year Bagasse production (dry basis) 140 kg/tc Straw production (dry basis) 140 kg/tc Fraction 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/tc Filter cake sucrose content (wet basis) 1.6% Filter cake moisture 70.0% Electric power demand 1G 30 kwh/tc Electric power demand integrated 1G2G 51 kwh/tc Steam consumption 1G 500 kg/tc 21

22 Appendix Total installed capacity added in Brazil: 22

23 Appendix Total installed capacity in Brazil: 23

24 NEO-CARBON Energy project is one of the Tekes strategy research openings and 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.