Conditioning of SO2-ethanol-water spent liquor for fermentation by clostridia

摘要

The present invention relates to producing chemicals and biofuels from wood material, e.g. mixed forest biomass. Specifically, the invention concerns a process for conditioning spent liquor produced by SO2-ethanol-water (SEW) fractionation of wood chips for fermentation to butanol, ethanol and acetone/isopropanol (so called ABE process) by Clostridia bacteria.

主权项

1. A method for conditioning of a biomass-derived liquor containing sulfur dioxide, said method comprising:
(a) obtaining a first liquor derived from cooking and washing a biomass feedstock, wherein said first liquor comprises sulfur dioxide, water, hemicelluloses, and lignin; (b) evaporating and stripping said first liquor to remove a first amount of sulfur dioxide, thereby generating a second liquor; (c) increasing the pH of said second liquor to precipitate and remove a second amount of sulfur dioxide, in the form of lignosulfonate, thereby generating a third liquor comprising sulfite anions; and (d) exposing said third liquor to catalytic oxidation in the presence of a ferrous sulfate-based catalyst and an oxidant under effective reaction conditions to oxidize said sulfite anions to sulfate anions, thereby generating a conditioned liquor.