Patent ID: 6254723
Filing Date: 2001-07-03
Classification: D21C

Abstract:
A method for continuous cooking of kraft pulp in a single vessel system, comprising:(a) conveying chips and liquor in a transfer line from a high pressure feeder to a first end of a digester;(b) separating a first portion of the liquor from the chips;(c) withdrawing the first portion from an outlet being defined at an upper part of the digester;(d) conveying the first portion in a return line to the high pressure feeder, the return line being in operative engagement with the digester at the outlet;(e) cooking the chips in a concurrent cooking zone disposed in the digester;(f) extracting black liquor from at least one extraction screen section disposed in the digester;(g) discharging cooked pulp at a second end of the digester, the second end being opposite the first end;(h) conducting a constituent flow of liquor away from the return line;(i) heating the constituent flow of liquor in a heating arrangement; and(j) feeding the constituent flow of liquor via an inlet into the digester at a location that is downstream of the outlet at the upper part of the digester.