Patent ID: 8211680
Filing Date: 2012-07-03
Classification: C07C,C12P,Y02E

Abstract:
1. A process for producing fermentable sugars and an alkaline acetate from a biomass-derived extract, said process comprising: (a) providing a liquid extract produced during steam or hot-water cooking of biomass, wherein said liquid extract comprises hemicelluloses, acetic acid, dissolved lignin, and suspended solids; (b) clarifying said liquid extract by sedimentation or centrifugation for removing said suspended solids, to produce a clarified extract; (c) introducing said clarified extract to an ultrafiltration unit for removing said dissolved lignin with a molecular-weight cutoff range of 3,000 g/mol to 10,000 g/mol, to produce an ultrafiltration concentrate comprising said dissolved lignin and an ultrafiltration permeate comprising said hemicelluloses and said acetic acid; (d) introducing said ultrafiltration permeate to a nanofiltration unit for removing said hemicelluloses, to produce a nanofiltration concentrate comprising said hemicelluloses and a nanofiltration permeate comprising said acetic acid; (e) combining said nanofiltration permeate with an alkaline additive for converting said acetic acid to an alkaline acetate, to produce a reverse-osmosis feed stream comprising said alkaline acetate; (f) introducing said reverse-osmosis feed stream to a reverse-osmosis membrane, to produce a reverse-osmosis permeate comprising water and a reverse-osmosis concentrate comprising said alkaline acetate; and (g) introducing said nanofiltration concentrate to a hydrolysis reactor, to produce a hydrolyzate comprising fermentable sugars.