Compensated Kappa Factor Control at Canfor Ltd., Prince George, B.C., 2000 Pulping / Process & Product Quality Conference Proceedings

D. Pryke, S. Fairless, R. Laurendeau, T. Johnson--In October 1999, Canfor Ltd.’s, Prince George, B.C. upgraded the control strategy from Compensated Brightness Control (CBC) to Compensated Kappa Factor Control (CKFC) in the Do stage of their market pulp mill. The pulp mill bleaches oxygen delignified softwood at 20 kappa no. using a DoEopDEpD sequence. The pulp mill produces approximately 290,000 ADt per year at 90% ISO brightness for the international market.

An assessment of the Compensated Kappa Factor Control (CKFC) strategy compared to the prior Compensated Brightness Control (CBC) strategy over both long and short term operating periods showed:

* The Do kappa factor, DoEop kappa factor and overall bleaching sequence kappa factor decreased significantly;

* Overall bleaching costs decreased approximately 5% - 7%;

* Oxidizing chemical consumption decreased 8-9%;

* Bleaching costs (based on oxidizing chemicals) decreased 10%;

* Pulp quality was maintained; and

* Final brightness variability decreased.

The operators readily adopted the new control strategy and availability of the control system has averaged 97%.