Direct Wood Liquefaction with Hydroalcoholic Hydrogen-donor Mixtures at Supercritical Conditions

The shortcomings of currently available systems suggest that a potential giant step in the improvement of conversion technology lies in the development of a single-step biomass conversion process that does not involve molecular hydrogen. The liquefaction of pure cellulose, poplar wood or corn starch with binary hydrogen-donor mixtures such as isopropyl alcohol-water has been studied in a batch autoclave system under inert atmosphere. Reaction conditions involved temperatures between 260 and 350 C, residence times between 30 and 90 minutes and pressures between 0 and 100 atmospheres.The use of homogeneous and heterogeneous hydrogenolysis catalysts has also been investigated. Under optimum reaction conditions conversion of initial cellulose higher than 70% have been observed with oil yields greater than 50%. Furthermore due to the initial presence of water a mixture of sugars and nonfermentable byproducts (0-30 X yield) are obtained which, if converted to liquid fuels, can modify this traditionally undesirable situation into new opportunities. Further work is in progress in order to achieve complete conversion of wood to oil derivatives.