METHOD OF IMPROVING BLEACHABILITY AND RUNABILITY OF KRAFT PULPS

摘要

A method for use in a batch digesting process is provided which includes the removal (76, 92) of a portion of the hot cooking liquor from the digester (10) prior to the cook creating a liquid-vapor interface (90) in the digester followed by the removal (92) or purging of the vapors disposed above the liquid-vapor interface and the reduction of the pressure in the digester to about the saturation pressure of the hot cooking liquor. The inclusion of these steps in the process helps to eliminate a coating on the pulp fibers which has been found to inhibit the bleachability and runability of the fibers. Accordingly, an apparatus and method for the batch digesting of pulp fibers is provided which provides pulp fibers having improved bleachability and runability characteristics.