Conversion of Algal Biomass to Drop-In Fuels

This project will develop and evaluate a new process for converting algal biomass into renewable drop-in fuels. Renewable fuels are liquid fuels made from biomass that are a direct substitute for the standard, petroleum- derived fuels. For example, renewable diesel has a higher heat of combustion and a lower molecular weight than biodiesel (which is a methyl ester of fatty acids) and better cold flow properties. Of all available biomass, lipids (from oil seeds plants or algae) are the most chemically similar to diesel fuel (both are primarily long chain hydrocarbons). Therefore, lipids are the most efficient feedstock from which to produce renewable diesel. Another good feedstock is the bio-crude made during the hydrothermal liquefaction (HTL) of total algal biomass. This uses all of the algae, not just the lipids, but makes a crude feedstock that is more heterogeneous and has a smaller average molecular weight than algal oil. Bio-crude can be converted to a mixture of gasoline, jet fuel and diesel. The difference between lipids (or bio-crude) and diesel fuel is that lipids contain about 10% oxygen and diesel contains no oxygen. The key is to develop the most efficient method of removing the oxygen content from lipids (and removing oxygen and nitrogen from bio-crude) and to produce a hydrocarbon fractions that are indistinguishable from standard diesel (and naphtha). In this SBIR Phase I project we will demonstrate and evaluate a new catalytic process for converting lipids and bio-crude (algal biomass processed with hydrothermal liquefaction) into renewable diesel in a bench scale unit. The process uses a new approach to deoxygenation that is not dependant on co-processing with sulfur-rich fossil feedstocks and that can use a broad spectrum of natural algal feedstocks while producing a 100% renewable fuel. The liquid fuel will be analyzed by gas chromatography, mass spectroscopy and elemental analysis to determine the degree of oxygen removal and the product distribution. Lastly, an economic analysis will determine the profitability of the process. The commercial application is a new process for converting algal lipids and bio-crude into renewable diesel, jet fuel and gasoline. Renewable, drop-in fuels can be used in standard engines for on-road transportation. The benefits of using renewable fuels such as diesel include reduced CO2 emissions, reduced sulfur emissions and a reduced dependence on petroleum. Renewable diesel (not co-processed with petroleum) helps to meet the requirements of the federal renewable fuels standard.