Integrated catalytic process for obtaining liquid fuels from renewable lignocellulosic biomass

An integrated process for obtaining liquid biofuels is reported. The process is based on the separation of a lignocellulosic feedstock into cellulose and low-molecular-weight lignin (LMWL) followed by their conversion into two types of liquid biofuels, namely, hydrocarbon mixtures and bioalcohols. Different methods of wood fractionation into cellulose and LMWL—mechanical, steam explosion, and selective oxidation methods and their combinations—are compared. The amount of cellulose derived from wood and the amount of hydrolysate obtained from this cellulose for ethanol biosynthesis are determined by the efficiency of the method used for the fractionation of the lignocellulosic material. The best results are achieved by combining mechanical activation and subsequent catalytic oxidation of wood. Use of the resulting high-quality glucose solution, which are free of pentoses—sugars inhibiting ethanol biosynthesis—allows the alcohol yield to be increased by 30–35%. Liquid hydrocarbon mixtures enriched with phenols and products of their alkylation with ethanol have been obtained by thermal processing of LMWL in ethanol at an elevated pressure.