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Unformatted text preview: Microalgal Biodiesel What is Biodiesel? Alkyl Esters (biodiesel) are produced in simple transesterification reaction of oil and alcohol Reaction usually performed in the presence of a Alkali Catalyst such as Sodium Hydroxide Process is the same for all oil sources Biodiesel can be used in unmodified diesel engines with synthetic fuel lines Biodiesel can be blended with petrodiesel in any proportion Microalgae as Biodiesel Feedstock
Crop Oil Yield L/ha Land Area Mha Corn 172 1540 Soybean 446 594 Cornola 1190 223 Jatropha 1892 140 Coconut 2689 99 Oil Palm 5950 45 Microalgae 70% Oil Yield 136900 2 Microalgae 30% Oil Yield 58700 4.5 Land area Comparison for meeting 50% of all U.S.transport Percent of Existing U.S. Cropping Area 846 326 122 77 54 24 1.1 2.5 fuel needs Oil Yields can vary widely depending on species and growing conditions, most conservative estimates show that 30-50% oil by mass is attainable on a large scale, with some species producing up to 80% oil by mass Microalgae is not a food competing feedstock like corn or soy Unlike oil crops, microalgae can be grown on non fertile land Aquaculture of AlgaeRaceway Ponds Algae is pumped through shallow troughs with paddlewheels Low cost of construction and maintenance Affected by contamination of unwanted organisms Significant evaporative losses of CO2 and water Seminal work for microalgae, Aquatic Species program was performed using this method Aquaculture of AlgaePhotobioreactors Good control of media chemistry Significant build and maintenance costs Closed loop system resists growth of unwanted organisms Moderate evaporative losses Aquaculture of AlgaeFermentation Venture funded biotech company Solazyme, uses a fermenation process through which algae are fed waste products such as corn stover, wood chips, switchgrass, etc. and convert sugar to oils No photosynthesis takes place Solazyme signed agreeement with Chevron Technology Ventures in January 2008 for testing and development Also released Soladiesel in January at Sundance film festival which exceeds ASTM standards for biodiesel Economic Analysis & Competition with Petroleum Economic models of Microalgal Biodiesel varies widely but at present it is not competitive with petroleum based fuels One source puts the price of microalgal oil at about $500 a barrel but assumes needed CO2 is available at zero cost Means of Increasing Economic Feasibility Biorefineries Photobioreactor engineering Genetic modification of microalgae CO2 Capture Biorefineries & MicroAlgae Farms Spent Biomass after oil extraction is rich in protein and carbohydrates Possible markets and uses include agricultural feed, ethanol production via fermentation, and chemical production CH4/CO2 production via anaerobic digestion could provide needed carbon for algae growth as well as power to run refinery Environmental Impacts U.S. D.O.E. study in 1998 showed net lifecycle reduction of 78% in CO2 and 32% in soot emissions using oil crop based biodiesel These conclusions are supported by the U.S. D.O.E.'s Aquatic Species Program conducted from 1978 to 1996 which investigated microalgae growth for purposes of energy production Superior photosynthetic properties of microalgae make it the only biofuel feedstock capable of providing significant quantities of energy sustainably ...
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- Spring '08