Conditioning of so2-ethanol-water spent liquor for fermentation by clostridia
AssigneeAPI Intellectual Property Holdings, LLC
InventorsAdriaan Van Heiningen, Evangelos Sklavounos
Life of this patent
Estimating the term…
Abstract
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.
Claims21
1-5. (canceled)
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.
A process for fractionating biomass to prepare sugars for bacterial fermentation, said process comprising:
- (a) exposing a biomass feedstock to a liquid solution comprising sulfur dioxide, water, and an aliphatic alcohol, under effective cooking conditions to generate pulp;
- (b) pressing and washing said pulp to separate washed pulp from spent liquor, and recover each of said spent liquor and said washed pulp, wherein said spent liquor comprises sulfur dioxide, water, aliphatic alcohol, hemicelluloses, and lignin;
- (c) evaporating and stripping said spent liquor to remove a first amount of sulfur dioxide, thereby generating a stripped liquor;
- (d) increasing the pH of said stripped liquor to precipitate and remove a second amount of sulfur dioxide, in the form of lignosulfonate, thereby generating a pH-adjusted liquor comprising sulfite anions;
- and
- (e) exposing said pH-adjusted 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 containing sugars suitable for bacterial fermentation.
Dependencies are inferred from the claim text.