BIOMASS FRACTIONATION PROCESS

摘要

BIOMASS FRACTIONATION PROCESS Disclosed is a process for extracting lignin from lignocellulosic material to recover reactive lignin and to yield high quality cellulosic pulp, which comprises the steps of: (a) impregnating lignocellulosic material with a liquor which comprises an aqueous organic solvent and an acid neutralizing agent; (b) heating the liquor with the impregnated lignocellulosic material submerged therein from a temperature of about 150.degree.C to a maximum temperature in the maximum temperature range of 200.degree.C to 280.degree.C and then cooling the liquor with material submerged therein to a temperature of less than about 150.degree.C; (c) maximizing reactive lignin solvation while suppressing cellulose degradation during step (b) by: i. controlling the amount of neutralizing agent in step (a) to achieve a final pH for step (b) of from 6.0 to 8.0 in the liquor during heating in step (b) from about 150.degree.C to about 175.degree.C, and ii. maximizing the time at which the liquor is within the maximum temperature range during step (b) by rapidly cooling the liquor to terminate step (b); and (d) recovering reactive lignin and high quality cellulose pulp from the cooled liquor.