Experience at Weldwood of Canada Limited, Hinton Division, indicates t
hat reducing the dissolved organics content in the MC zone of a dual v
essel hydraulic Kamyr MCC(R) digester on northern softwood can result
in improved washing and an increase in tear strength. The technology,
Lo-Solids(TM) cooking, was developed by Ahlstrom Kamyr Inc. in 1993, a
nd implemented in Hinton in 1994. The trial involved gradually increas
ing the dilution factor from 1.1 to 2.3 and increasing extraction fact
or from 1.4 to 1.6 by introducing cold blow into the MC zone, and simu
ltaneously extracting cooking liquor off the MC zone. Tear strength in
the finished pulp product was improved by 5 to 7%. Digester column mo
vement was improved both in summer and winter operation. Defoamer usag
e in brownstock was decreased by 18%. Digester K# and liquor usage wer
e unchanged as a result of the trial.