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Cellulose production from lignocellulosic biomass

  • US 20020148575A1
  • Filed: 02/20/2002
  • Published: 10/17/2002
  • Est. Priority Date: 08/16/2000
  • Status: Active Grant
First Claim
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1. A method of treating lignocellulosic biomass containing lignin to produce purified cellulose, said method comprising:

  • providing a lignocellulosic feedstock;

    introducing said feedstock into a pressure vessel having at least two reaction zones;

    heating said feedstock in a first reaction zone to a temperature of from about 180°

    C. to about 240°

    C.;

    removing hydrolized hemicellulose from the heated feedstock;

    transferring said heated feedstock from said first reaction zone to a second reaction zone;

    subjecting said feedstock in said second zone to a counterflow of hot wash water containing dissolved oxygen and having a pH of at least 11 to produce residual solids containing cellulose and a wash water containing lignin and other extractives; and

    separating the residual solids containing purified cellulose from the filtered wash water, wherein the separated cellulose contains less than 10% lignin.

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