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Process for high temperature peroxide bleaching of pulp with cool discharge

  • US 7,297,225 B2
  • Filed: 06/22/2004
  • Issued: 11/20/2007
  • Est. Priority Date: 06/22/2004
  • Status: Expired due to Term
First Claim
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1. A process for bleaching cellulosic pulp, comprising:

  • providing a stream of cellulosic pulp;

    adding to the stream of cellulosic pulp at least one composition for bleaching;

    bleaching the stream of cellulosic pulp in a pressure vessel at a temperature at or above about 212°

    F. and the atmospheric flash point of the cellulosic pulp to form a stream of bleached cellulosic pulp;

    cooling the stream of bleached cellulosic pulp prior to discharge from the pressure vessel by adding at least a portion of a cooled filtrate stream to the stream of bleached cellulosic pulp to form a cooled stream of bleached cellulosic pulp that is at a temperature below the atmospheric flash point of the bleached cellulosic pulp,dewatering the cooled stream of bleached cellulosic pulp to obtain a bleached cellulosic pulp residue stream and a hot filtrate stream; and

    forming the cooled filtrate stream by cooling the hot filtrate stream.

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