CONVERSION OF SEAWEED BIOMASS INTO KETONE FUEL INTERMEDIATES THROUGH CARBOXYLATE PLATFORM PROCESSING XIN CHEN, SAMPATH KARUNARATHNE, YANG YU, PAIGE CASE, M. CLAYTON WHEELER, G. PETER VAN WALSUM*, DEPARTMENT OF CHEMICAL AND BIOLOGICAL ENGINEERING FOREST BIOPRODUCTS RESEARCH INSTITUTE UNIVERSITY OF MAINE, ORONO
Motivations High oil price Liquid biofuels from non-foodcompetitive resources Environmental concerns Sustainable energy requirements liquid energy requirements Reduction of resources for food.
SUGAR PLATFORM Organic material Preteatment Fatty acids Hydrogen Sugars Chemical intermediates Hydrocarbons Ethanol
SOME ISSUES Fatty acids: difficult to extract from biomass. Chemical catalysis: complex processes, heterogeneous catalysts Ethanol: blend wall limitations
CARBOXYLATE PLATFORM Organic material Preteatment Organic acids Hydrogen Mixed Carboxylic acids Ketones Alcohols Hydrocarbons Esters
MIXED CULTURE ANAEROBIC FERMENTATION Fermentation Advantages: Wide range of substrates possible No need of additional enzymes: natural CBP No need of sterile operations Adaptability to changes in substrate/operation Naturally available inoculums Inexpensive fermentors: plastic, concerete
ALGEFIBER A waste product of seaweed processing in carrageenan extraction process Alkaline treatment Extraction Carrageenan Red Seaweed (Red algae) Algefiber (Seaweed Sludge) Alkaline pretreated (exclude alkaline pretreatment) Locally available (FMC Biopolymer, Rockland, ME) Continuous production (60 tons /Day) Derived from non-lignocellulosic biomass (seaweed) 7 Does not compete with terrestrial biomass (food crops, forest etc.)
BROWN SEAWEED (KELP) One of the most abundant biomass sources in the world Does not require land or freshwater resources Grows faster than other biofuel feedstocks Easily harvested High carbohydrate content Almost zero lignin
BROWN SEAWEED (KELP) David P. Chynoweth et al., 1980 Carbohydrate: 71% of organics
SACCHARINA LATISSIMA
CARBOXYLATE PLATFORM PROCESSING Kelp, Ca(OH)2, CaCO3, CHI3 1 2 3 5 Hydrogen Pretreatment Fermentation Evaporation Carboxylate Salts 4 Thermal deoxygenation Ketones 7 Hydrogenation CaCO3 6 Alcohols Kelp Anaerobic Fermentation Acetic acid CaCO3 440-480 C H 2 Calcium acetate acetone alcohol
Lime Pretreatment: High or Low Temperature/Pressure 50 to 160, days to minutes, 0.1 g Ca(OH) 2 /g biomass, 5-15 g H 2 O/g biomass.
MIXED CULTURE ANAEROBIC FERMENTATION Measurements: C2~C7 acids concentration. Gas volume Carbon dioxide and methane content. Ethanol and lactic acid content. Solids analysis.
ALGEFIBER FERMENTATION
MIXED CULTURE ANAEROBIC FERMENTATION
PRETREATED KELP IN 20 L BIOREACTORS
Acids conc. (mg/l) Total acids conc. (g/l) KELP FERMENTATION, 20 L SCALE 6000 5000 4000 3000 2000 1000 0 acet prop i-buty n-buty i-vale n-vale i-capr capr 0 5 10 15 20 25 30 35 hept Time (day) 16 14 12 10 8 6 4 2 0 Total Acids in Kelp Fermentation 0 5 10 15 20 25 30 35 Time (day)
PERCOLATION COLUMNS IN SERIES Four columns contained within one temperature controlled box box.
COLUMNS IN SERIES: COUNTER CURRENT Fresh solids Transfer liquid 1 week solid s Transfer liquid 2 week solids Transfer liquid 3 week solids Fresh liquid Spent liquid
ACID PRODUCTION IN SERIAL COLUMNS
COUNTER CURRENT PERCOLATION FERMENTATION Columns 10, 11, 12 achieved max titer of 14 g/l in two weeks
ACIDOGENIC FERMENTATION: TEMPERATURE EFFECTS
FERMENTATION MASS BALANCE: VS
CARBOXYLATE PLATFORM PROCESSING Kelp, Ca(OH)2, CaCO3, CHI3 1 2 3 5 Hydrogen Pretreatment Fermentation Evaporation Carboxylate Salts 4 Thermal deoxygenation Ketones 7 Hydrogenation CaCO3 6 Alcohols Kelp Anaerobic Fermentation Acetic acid CaCO3 440-480 C H 2 Calcium acetate acetone alcohol
THERMAL DEOXYGENATION (TDO) Neutralizing the carboxylic acids into calcium carboxylate salts Evaporating the neutralized solution to obtain dry calcium carboxylate salts Thermal deoxygenating calcium carboxylate salts into mixed ketones
THERMAL DEOXYGENATION EQUIPMENT (TDO)
THERMAL DEOXYGENATION KETONE PRODUCTS
NMR ANALYSIS OF TDO PRODUCTS NMR
KETONIZATION OF FERMENTATION (ALGEFIBER TM ) SALTS
THERMAL DEOXYGENATION (TDO)
SCALING UP TDO: 10 ML 300ML 3 L 2L CONT. 50 L
CONCLUSIONS Fermentations are robust and autohydrolytic. The optimal condition for the fermentation, accounting for downstream processing, is using lime pretreated kelp with CaCO 3 buffer and enriched inoculum at 37. TDO on the kelp fermentation salt successfully produced product with high ketone content and comparatively high energy content. So far, scale up of fermentation and TDO do not appear to present major problems.
ACKNOWLEDGEMENTS Many thanks to: Nick Hill, Diane Smith FMC Biopolymer for Algefiber supply Ocean Approved TM and Gary Arnold for Kelp supply. Work funded by the US DoT Northeast SunGrant Initiative US DOE grant # DE-FG36-08GO18165