Patent ID: 6280567
Filing Date: 2001-08-28
Classification: D21C

Abstract:
A method for preliminary treatment of a disintegrated cellulose-containing material prior to pulp digestion, comprising:(a) providing a pressure in a process vessel that is substantially similar to an atmospheric pressure;(b) pre-impregnating the cellulose-containing material in the process vessel with a sulphur-containing alkaline liquor, the cellulose-containing material flowing in a downstream flow direction;(c) feeding the pre-impregnated cellulose-containing material to a sloping steaming vessel, the sloping vessel being downstream of the process vessel;(d) separating off an amount of the liquor from the cellulose-containing material in the sloping steaming vessel, the amount being a substantial portion of a total amount of the liquor to be conveyed to a chemical recovery unit;(e) steaming the pre-impregnated cellulose-containing material in the sloping steaming vessel;(f) passing the liquor from step (d) through a heat exchanger;(g) dividing the liquor from step (f) into a first subsidiary stream and a second subsidiary stream;(h) flashing an extraction liquor from pulp digestion to generate a steaming vapor for steaming in step (e); and(i) collecting and condensing foul-smelling gases from steps (b) and (e).