Catalytic Conversion of Biomass to Liquid Fuels and Chemicals
Prof.Dr. James A. Dumesic (Department of Chemical and Biological Engineering University of Wisconsin-Madison)
Environmental and political issues created by our dependence on fossil fuels, such as global warming and national security, combined with diminishing petroleum resources are causing our society to search for new renewable sources of energy and chemicals, and an important sustainable source of organic fuels, chemicals and materials is plant biomass. We outline how heterogeneous catalysts can be used in a cascade mode, where the effluent from the first reactor is fed to the second reactor, to selectively remove oxygen moieties from carbohydrates to produce specific classes of hydrocarbons for use as liquid transportation fuels. In one approach, a bi-metallic catalyst in the first reactor is used to produce mono-functional compounds (such as alcohols, ketones, carboxylic acids, and heterocycles), and acidic zeolite catalysts or bi-functional catalysts containing metal and acid/base sites in a second reactor are used to achieve C-C coupling reactions. This cascade approach can be tuned for production of highly branched hydrocarbons and aromatic compounds in gasoline, or for production of longer chain, less highly branched hydrocarbons in diesel and jet fuels. We also present a catalytic cascade approach for the conversion of solid cellulose to liquid hydrocarbons, involving the intermediate production of levulinic acid.