Patent ID: 9012188
Filing Date: 2015-04-21
Classification: C12P,D21C,Y02E

Abstract:
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.