Patent ID: 8404051

Claim:
A method of preparing lignin from lignocellulosic biomass, comprising: providing lignocellulosic biomass under a first pressure of at least about 220 bar and at a first temperature of at least about 360° C., comprising: a first solid fraction comprising: insoluble lignin; and a first liquid fraction comprising: soluble C 6 saccharides; and soluble lignin; wherein said lignocellulosic biomass is fractionated to remove at least a portion of C 5 saccharides prior to said providing step; gradually reducing said first pressure of said lignocellulosic biomass to a second pressure while substantially simultaneously and gradually reducing said first temperature of said lignocellulosic biomass to a second temperature at least about 1° C. above the glass transition temperature of lignin at said second pressure; wherein said first liquid fraction is not substantially gasified; and substantially simultaneously reducing said second pressure and said second temperature to a third pressure and a third temperature in a time less than about 1 second to precipitate said soluble lignin in said first liquid fraction and form a mixture comprising: a second solid fraction comprising: insoluble lignin; and precipitated lignin; and a second liquid fraction comprising: soluble C 6 saccharides.