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Continuous Flowing Pre-Treatment System with Steam Recovery

  • US 20080064906A1
  • Filed: 09/30/2005
  • Published: 03/13/2008
  • Est. Priority Date: 09/30/2004
  • Status: Active Grant
First Claim
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1. A continuous process for pre-treating a lignocellulosic feedstock, comprising:

  • (a) providing a feedstock slurry having a solids concentration of 8% to 30% by weight;

    (b) pumping the feedstock slurry through a heating train of two, or more than two heating stages, each heating stage including a pump to increase heating stage pressure and a direct steam injection to heat the feedstock slurry;

    (c) adding acid to the feedstock slurry prior to the heating train, during a heating stage, or after leaving the heating train, the acid added at a concentration of 0% to 12% weight of acid on weight of initial feedstock, to produce a heated, acidified feedstock slurry;

    (d) flowing the heated, acidified feedstock slurry through a pre-treatment reactor at a temperature of 160°

    C. to 280°

    C. for a time sufficient to increase efficiency of conversion of cellulose in the feedstock to glucose using cellulase enzymes;

    (e) cooling the slurry after the slurry exits the pre-treatment reactor, using two, or more than two flashing stages at successively lower pressures, without intermittent increases in pressure;

    (f) using steam energy from two or more than two of the flashing stages, at or near its flash temperature, to heat the feedstock slurry in the heating train.

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