Bioenergy II (RIO DE JANEIRO 8-13 March, 2009)
Biofuels Production from Volatile Fatty Acid Platform
Ho Nam Chang Professor of Biochemical Engineering Department of Chemical & Biomolecular Engineering, Korea Advanced Institute of Science and Technology KAIST), 373-1, Guseong-dong, Yuseong-gu, Daejeon, 305-701, Republic of Korea E-mail:
[email protected], Tel: +82-42-350-3912, Fax: +82-42-350-3910
Biofuel
What are VFAs? : Volatile Fatty Acid, carboxylic acid with less than C6 Organic materials with suspended colloidal form
Protein
Carbohydrate
Lipid
Hydrolysis Amino acids
Sugars
Free long chain fatty acids + glycerol
• No need sterilization • No additional hydrolysis enzyme • Mixed culture • Acidogenesis : fast • Methanogenesis : slow
Acidogenesis
O
Ammonia
Volatile fatty acids, alcohol
OH
Acetogenesis
Hydrogen, carbon dioxide
Acetic acid
Acetic acid Propionic acid Butyric acid Valeric acid Caproic acid
(C2) (C3) (C4) (C5) (C6)
O
Methanogenesis
OH
Biogas (Methane, carbon dioxide)
Biofuel
2
VFAVFA-based Biofuels 1. Pretreatment (lignin: little, regular) 2. VFA (slow high rate) 3. Concentration of VFAs (30g/L (30g/L 400g/L) • Evaporation (25kwh/m3 ton of water) • Solvent extraction (efficiency durability) 4. Hydrogenation (catalytic, 200oC, 20 atm) atm) • CH3COOH + 2H2 C2H5OH + H2O • Propionic acid + 2H2propanol + H2O • Butyric acid + 2H2butanol +H2O 5. Separation to ethanol, propanol, propanol, butanol
Biofuel
3
VFA Platform Principle Disintegration Hydrolysis
Application Oct. 2008, presented in International Workshop on Defining Issues in Biofuels R&D
VFAs
Gas, Liquid Biofuels Biochemicals
Biofuel
Acetate
C3
Propionate
C4
Butyrate
C5
Valerate
C6
Caproate
Biological and chemical processes
BioChemicals
Biological & thermochemical process
C2
Methane
Liquid
Anaerobic digestion
Acetogenesis & Hydrogenesis
VFAs
BioFuels
Fermentation & Anaerobic Oxidation
Raw Materials
Gas
extracellular enzymatic process
Ethanol
BioHydrogen
Butanol Microbial Biodiesel
Bioplastics Bulk chemicals(C3 ~C6) Pharmaceuticals Textiles Other value added chemicals 4
Production Routes of Fuel Alcohols Fermentation : one of the key technologies in biological conversion
Acetate Thermal conversion, Catalysis
Fermentation Hydrolysis
Biomass
Sugars Fermentation (80 gal/ton)
Ethanol
(56 gal/ton) (85 gal/ton)
Syngas Catalysis
Biological Process Chemical Process
Mixed alcohol
(120 gal/ton)
VFA
(current yield in pilot-scale) * VFA: volatile fatty acid
Biofuel
5
Liquid Biofuel Costs (2005~2030)
Whole-sale sale Petroleum Product Price ($/L, 2005 2005-2006)
Ethanol
Diesel
Biofuel cost (2006~2030)
$130/bbl
$100/bbl Fischer Tropsch
Wheat Beet
$50/bbl
Corn
Sugar cane
Biofuel
Vegetable oils Anima fats
Ligno cellulose Source:
6
Cost Comparison 1.1 Bioethanol present cost range
Ethanol Production Cost ($/L)
1.0
Bioethanol cost estimation by 2030 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2
(Sugar platform) 1)
Sugarcane 1) Corn 1) 1) Estimated
Biofuel
2)
(VFA platform) 2)
Lignocellulose
by IEA/OECD, 2006
Estimated by M. Holtzapple, 2009
7
Demand for New Process Development Flexible application to various biomass • • • • • •
Organic wastes Agricultural wastes Forest residues Energy crops Marine biomass MSW
Cost effective process • • • • • • • • •
No sterility No GMOs Adaptable No pure cultures Low capital No enzymes High product yields No vitamin addition Co-products not required
Requirement of new biorefinery platform less sensitive to species, composition, and water content of biomass Biofuel
8
Search for New Biofuel Platform 1. Abundant Raw Materials in Korea and in other countries. Materials with negative cost: foodwaste, sewage sludge, fallen leaves and other biodegradable organic wastes
2. Do I have a good technology and experience ? Fermentation with high cell density culture (1982~ ) Foodwaste treatment since 1996 3. The cost of production should be competitive, vs. existing biofuels (sugar cane, grain-based; $100 bbl-oil) Even at a smaller scale, the product should be marketable so that technology development may go on. My group started biofuel research in 2005. We came to a conclusion. VFA-platform
Biofuel
9
Mass
(Alcohol production from lignocellulosic biomass) Composition
Cellulosic Ethanol (Sugar platform)
C6
38%
C5
27%
Lignin Ash Others
20% 3% 12%
→ →
(VFA platform)
C6 C5 Lignin Ash Others
38% 27% 20% 3% 12%
Hydrolysis
90%
90%
90%
90%
C6 ferment. 51%
→ →
90% 90%
→
90%
30%
Pretreat.
C5 Recovery Sum EtOH ferment. 95% 14.91% 51%
Anaerobic digestion 76% 76%
Composition
Mixed Alcohol
Pretreat.
95%
10.60%
95% 95%
Hydrogen Rxn 77% 77%
Sum Alcohol 19.01% 13.51%
95%
77%
2.37%
VFA recovery
Total EtOH
25.51% (319 L/t)
Total Alcohol
34.89% (436 L/t)
Money Cellulosic Ethanol Return $ = $0.3/kg(EtOH) * 0.2551/kg biomass = $ 0.0765/kg biomass (Biomass cost = 52.3%) Mixed Alcohol
Return $ = $0.3/kg(EtOH) * 0.3489/kg biomass = $0.105/kg biomass (Biomass cost = 38.1%) * Biomass price = $40/tonne
Energy Cellulosic Ethanol Y= 25.51% → 26.84 MJ/kg * 0.2749 kg/kg = 7.28 MJ/kg biomass Mixed Alcohol
Y= 34.89% → 30.2 MJ/kg1 * 0.3489 kg/kg = 10.54 MJ/kg biomass (9.28 MJ/kg) 2 1 2
Biofuel
Ethanol:Propanol:Butanol = 6:1:3 H2 consumption = - 120 MJ/kg*0.3489*0.03 g H2/g alcohol = - 1.256 MJ 10
Korean Foodwastes Foodwastes Composition
Amount of producible alcohols
Item
Content
Sugar platform
VFA platform
Total Solid(TS), [%]
21
(% of TS)
(% of TS)
Volatile Solid(VS), [%]
83
Fibers in TS, [%]
7.05
Lipids in TS, [%]
15.5
9.9
Proteins in TS, [%]
17
6.4
Carbohydrates in TS, [%]
40
(Average values of Korean foodwastes)
4.0
3.5
22.5
20 Sum : 23.5
600 psi) (> 40.8 atm) - widely used in industry (e.g., for making detergent alcohols from fatty acids)
• Reduced CuO-ZnO catalyst - low temperature (~150˚C) - low pressure (
