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life cycle assessment of biobutanol production integrated to sugarcane biorefineries in Brazil
Lucas G. Pereira Brazilian Center for Research in Energy and Materials - CNPEM Brazilian Bioethanol Science and Technology Laboratory - CTBE
4th International Workshop – Advances in Cleaner Production São Paulo, Brazil, May 22nd – 24th, 2013
Why butanol?
• Butanol 33.4 MJ/kg (Ethanol 26.4; Gasoline 43.5)
• Fuel in gasoline engines – Drop-in (minor engines modifications required)
– Distribution through existing pipelines
– Less corrosion, no cold-start or phase-separation problems
– Higher blend rates than ethanol (gasoline, diesel, ethanol)
– Large potential market
• Widely used in the chemical industry – Solvent, plasticizer, coating, cosmetics, pharmaceuticals, raw material
– Market: US$ 6.5 bi in 2012, projected US$ 9.2 bi in 2015
propylene
Why butanol? • Produced from fossil resources
CRUDE OIL PETROCHEMICAL REFINERY
BIOMASS BIOREFINERY n-butanol acetone
OXO-ALCOHOL REFINERY
n-butanol
- 30-60 % cost advantage - Reduced GHGs in the production chain
(Cobalt Technologies)
Why butanol? • Big players: huge fund raising
Demonstration facility in Brazil (1/10th) R&D of fermentation technologies
Converting ethanol plants to butanol (USA)
[ ] R&D of fermentation technologies Industrial plant in Hull (United Kingdom)
[ ]
Produces and sells n-butanol in China (fermentation, corn)
[ ; ; ; ...]
HOW TO ASSESS THE SUSTAINABILITY?
pre planting operations
soil preparation planting cultivation harvesting sugarcane
transport
CanaSoft
biorefinerysimulation
usage model
economic analysis production cost IRR ...
social analysis manpower wages ...
environmental analysis (life cycle assessment) global warming acidification eutrophication ecotoxicity ozone layer depletion energy balance water use land use ...
AspenPlus®
biorefinery 1G
biorefinery 2G
biorefinery “n”
...
SimaPro®
input-output matrix
economic engineering
transportand use logistics
Virtual Sugarcane Biorefinery - VSB
Life Cycle Assessment
SimaPro Software (version 7.3.3)
CML 2 baseline 2000 v2.05 method
ecoinvent database version 2.2 + CTBE processes
• Production routes
SUGARS FERMENTATION Clostridium
acetone butanol ethanol
DISTILLATION
LIQUID or GASEOUS ETHANOL
CATALYSTS hydroxyapatite
butanol ethanol hexanol mixed alcohols
PURIFICATION
- Sugarchemistry: ABE fermentation (acetone:butanol:ethanol)
- Alcoholchemistry: ethanol to butanol conversion using catalysts
Virtual Sugarcane Biorefinery - VSB
Life Cycle Assessment
Agriculture Productivity: 85 ton/ha (5 year-cycle: 1 plant cane + 4 ratoon) Planting and harvesting: mechanical Straw recovery: 50 % (integral harvesting: tops and dry leaves) Cane stalks and straw transport: “rodotrem” (25.2 km mean transp. distance) Vinasse application: 186.2 m3/ha (6 % trucks, 31 % trucks/aspersion, 63 % channels/aspersion) Fertilizers plant cane: 30 kg N/ha, 180 kg P2O5/ha, 120 kg K2O/ha ratoon with vinasse: 90 kg N/ha ratoon area w/o vinasse: 120 kg N/ha, 150 kg K2O/ha
Life Cycle Assessment
Industrial Processing capacity: 500,000 kg hour-1 of sugarcane (>2,000,000 ton crop season-1 – ~200 days year-1) Arrangement: annexed distillery System: optimized cogeneration with 90-bar boiler integrated consumption of process steam (2.5 bar) reduced in 20% ethanol dehydrated in molecular sieves electric drives used in sugarcane preparation and juice extraction
• RS: regular microorganism (0.20 g butanol / g sugars)
• MS: mutant strain with
improved butanol yield (0.34 g butanol / g sugars)
• 1G Annexed distillery 25:50:25 (sugar:ethanol:butanol)
25 % JUICE
Biobutanol production 1G (ABE fermentation)
Ethanol: Saccharomyces cerevisiae (0.48 g ethanol / g sugars) RS: Clostridium saccharoperbutylacetonicum DSM 2152 MS: Clostridium beijerinckii BA 101
Sugarcane
Cleaning
Extraction of sugars
Juice treatment
Juicetreatment
Cogeneration of heat and power
Bagasse
SteamElectricity
Juice concentration
Juice concentration
Crystallization
Molasses
Drying
VVHPSugar
Fermentation
Distillation and Rectification
Dehydration
AnhydrousEthanol
Acetone
Butanol
Straw
Butanolplant
HydrousEthanol
Sugarcane
Cleaning
Extraction of sugars
Juice treatment
Juicetreatment
Cogeneration of heat and power
Bagasse
SteamElectricity
Juice concentration
Juice concentration
Crystallization
Molasses
Drying
VVHPSugar
Fermentation
Distillation and Rectification
Dehydration
AnhydrousEthanol
Pretreatment Hydrolysis
Glucose liquor
Acetone
Pentosesliquor
Butanol
Straw
Lignocellulose
Butanolplant
HydrousEthanol
Biobutanol production 1G2G (ABE fermentation) • RS: regular microorganism (0.20 g butanol / g sugars) • MS: mutant strain with
improved butanol yield (0.30 g butanol / g sugars)
• 1G2G Annexed distillery 50:50 (sugar:ethanol)
fermentation of pentoses liquor for butanol
Ethanol: Saccharomyces cerevisiae (0.48 g ethanol / g sugars) RS: Clostridium saccharoperbutylacetonicum DSM 2152 MS: Clostridium beijerinckii BA 101
Steam explosion
Hemicellulose
Simulation* results per tonne of processed sugarcane
*Simulation performed in Aspen Plus by Mariano et al. (2013), Bioresource Technology 135:316-323
Challenges in production by ABE fermentation
• Reduced butanol yield (0.34 g vs 0.48 g ethanol)
• Butanol and acetone are toxic to microorganisms
- problem in batch fermentation
- solution: vacuum fermentation (continuous recovery)
• High economic investment (~US$ 25 million)
- separated production plant
- sterile equipment
Product Price Unit Anhydrous ethanol 1 0.66 US$/L VVHP Sugar 1 0.48 US$/kg Electricity 2 60.98 US$/MWh Sugarcane 3 27.26 US$/ton Sugarcane trash 18.29 US$/ton Butanol (fuel) 4 1.03 US$/kg Butanol (chemical) 5 1.65 US$/kg Acetone (chemical) 6 1.16 US$/kg
Prices
1Six-years moving average prices (jan2002-dec2011) (CEPEA, 2012) 2Weighted average of auction based on energy from sugarcane bagasse (2011 value) 3Six-years moving average prices (jan2002-dec2011) (UDOP, 2012) 4Estimated based on the price per MJ of anhydrous ethanol 5Mariano et al. (2013) 6ICIS, 2012
Life Cycle Inventory products anhydrous ethanol, sugar, electricity, butanol, acetone
inputs sugarcane, straw, bagasse, fertilizers, transport, sulphuric acid, oil, enzyme, zeolites, equipment, building, chemicals inorganic, water treatment…(~350 inputs)
emissions ethanol, CO2 (biogenic), CO (biogenic), N2O, NOx, SOx, CH4 (biogenic), VOC, particulates…
LCA results
comparative impacts breakdown by stage LCA results
Ethanol emissions during distillation
Diesel Urea
Fertilizer emissions Diesel Urea Pesticide
emissions
comparative impacts per tonne of processed sugarcane
LCA results
Biobutanol (as chemical) vs Petrochemical
comparative impacts per kilogram of butanol LCA results
Economic allocation (chemical selling price)
Integrating environmental and economic assessments…
Economic parameters
SCENARIOS EBITDAA
US$ TC-1 InvestmentB
mi US$ IRR
% 1G 57.47 225 13.3
1G MS 56.08F / 62.32C 309 12.3F / 14.8C
1G RS 51.78F / 55.71C 309 10.5F / 12.3C
1G2G 59.71 327 11.3
1G2G MS 65.81F / 69.32C 405 13.9F / 15.2C
1G2G RS 63.56F / 65.70C 405 13.1F / 13.9C
A Earnings before interest, taxes, depreciation, and amortization
B From Mariano et al. (2013)
LCA coupled with economic parameters comparative impact per economic return
62.32 US$/TC IRR: 14.8%
69.32 US$/TC IRR: 15.2%
Gasoline
Butanol as fuel
Imported crude oil ~10,400 km
ANP (2011)
Petrol, at refinery, market mix, 2011/CTBE BR U (67 % REPLAN / 33 % REDUC)
300 km
300 km
4 % Imported petrol from the USA
Emissions CO2, CO, CH4, NOx, N2O... (MMA, 2011; GREET, 2010)
Life Cycle Assessment Impact per km with a flex engine vehicle (3.46 MJ/km*)
Gasoline - Gasoline A (75 % v/v) - Ethanol 1G (25 % v/v) - Amount: 79.5 g/km -Total GWP: 224 g CO2/km
* MMA (2011); Engine’s efficiency does not change as function of the type of fuel used (GREET, 2010)
-73%
GAS
Eth 1G
Eth 2G
Ethanol -Amount: 131.2 g/km -Total GWP:
60 g CO2/km (1G) 58 g CO2/km (1G2G)
But 1G MS
Butanol - Amount: 100.8 g/km - Total GWP: 85 g CO2/km (1G MS) 72 g CO2/km (1G2G MS)
-62% -68%
-74%
But 2G MS
Final remarks
• Biobutanol presents advantageous characteristics if compared to ethanol, but there are challenges…
• Most of the LCA environmental impacts of the butanol production are related to the agricultural stage
• Interpretation of LCA results coupled with economic parameters may be valuable
• LCI for the industrial stage must be improved (enzymes, pretreatment, equipment, chemicals…)
• Economic analysis (risk, strategic decision…)
Thank you! [email protected]
Lucas G. Pereira Mateus F. Chagas Marina O. S. Dias
Otavio Cavalett Antonio Bonomi
Financial support by