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METHOD FOR LOW WATER HYDROLYSIS OR PRETREATMENT OF POLYSACCHARIDES IN A LIGNOCELLULOSIC FEEDSTOCK

  • US 20100056774A1
  • Filed: 08/27/2009
  • Published: 03/04/2010
  • Est. Priority Date: 08/29/2008
  • Status: Active Grant
First Claim
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1. A method for hydrolyzing polysaccharides in a lignocellulosic feedstock to produce monosaccharides, comprising:

  • a) providing interconnected dewatering, plug formation and reaction zones, each of the dewatering, plug formation and reaction zones being provided with an inlet zone and an outlet zone, the outlet zone of the dewatering zone being operationally associated with the inlet zone of the plug formation zone and the outlet zone of the plug formation zone being operationally associated with the inlet zone to the reaction zone, wherein the pressure (Pr) in the reaction zone is from about 90 to about 680 psia;

    b) feeding an aqueous slurry of the lignocellulosic feedstock to the dewatering zone to produce a partially dewatered lignocellulosic feedstock and an aqueous liquid, wherein the pressure (Pdwi) of the aqueous slurry of the lignocellulosic feedstock at the inlet zone of the dewatering zone is related to Pr as follows;

    0≦

    Δ

    P<

    the lesser of [(Pr

    20 psia) and 220 psia], andwhere Δ

    P is the absolute difference in pressure between Pr and Pdwi in psiac) withdrawing, from the dewatering zone, a portion of the aqueous liquid to produce a withdrawn aqueous liquid, the withdrawn aqueous liquid being substantially free of solid lignocellulosic feedstock, and at a pressure which is lower than the pressure of the aqueous slurry of the lignocellulosic feedstock at the inlet zone of the dewatering zone;

    d) moving the partially dewatered lignocellulosic feedstock from the outlet zone of the dewatering zone to the inlet zone of the plug formation zone;

    e) forming a plug of lignocellulosic feedstock within the plug formation zone to provide a pressure seal between the outlet zone of the dewatering zone and the inlet zone of the reaction zone;

    f) feeding the plug of lignocellulosic feedstock from the outlet zone of the plug formation zone to the inlet zone of the reaction zone, wherein the pressure at the outlet zone of the plug formation zone is substantially the same as the pressure at the inlet zone to the reaction zone;

    g) maintaining suitable temperature and pH conditions in the reaction zone to hydrolyze polysaccharides in the lignocellulosic feedstock to produce the monosaccharides; and

    h) recovering the monosaccharides produced in step g).

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