Process for the chemical refining of cellulose pulp

摘要

A process is provided for the chemical refining of cellulose pulp which comprises, in sequence, the steps of: (1) impregnating the cellulose pulp with refining chemicals in an amount selected to effect chemical modification of the pulp; (2) adjusting the pulp consistency to within the range from about 30 to about 70%; and (3) passing the pulp in turbulent flow through an elongated reaction zone from one end to another end thereof in a gaseous atmosphere consisting essentially of steam and preferably containing less than 1% by volume of oxygen at a superatmospheric pressure within the range from about 5 to about 400 kPa and a temperature within the range from about 100 to about 150 DEG C. at which the chemical modification proceeds without a mechanical working sufficient to change the degree of beating of the pulp by more than about 2 DEG (Schopper-Riegler) and the freeness of the pulp by more than about 10 ml, and with less than an 8% change in the pulp dry solids content, at a flow rate such that the impregnated chemicals are substantially completely consumed by the time the pulp reaches the end of the zone.