Patent ID: 8895265

Claim:
A method of producing C 5 monosaccharides from lignocellulosic biomass, comprising: providing a fractionated lignocellulosic biomass at a first temperature of at least about 200° C. and a first pressure, wherein said fractionated lignocellulosic biomass comprises: a first solid fraction comprising: cellulose; lignin; and hemicellulose; and a first liquid fraction comprising: a soluble C 5 saccharide selected from the group consisting of C 5 oligosaccharides, xylose, arabinose, and mixtures thereof; separating said first solid fraction from said first liquid fraction; forming a slurry comprising said first solid fraction and water; fractionating said slurry at a second temperature of at least about 200° C. and a second pressure to form: a second solid fraction comprising: cellulose; and lignin; and a second liquid fraction, comprising: a soluble C 5 saccharide selected from the group consisting of C 5 oligosaccharides, xylose, arabinose, and mixtures thereof; wherein said second temperature is greater than said first temperature; optionally, separating said second solid fraction from said second liquid fraction; optionally, combining said first liquid fraction and said second liquid fraction to form a third liquid fraction; and optionally, hydrolyzing said second liquid fraction or third liquid fraction at a third temperature and a third pressure to form C 5 saccharides selected from the group consisting of C 5 oligosaccharides having fewer mer units, xylose, arabinose, lyxose, ribose, and mixtures thereof; wherein said fractionating said slurry is conducted substantially free of added acid.