DECREASING ECF BLEACHING COSTS WITH ENZYMES IN A MILL WITH OXYGEN DELIGNIFICATION - INCREASE PULP BRIGHTNESS, AS WELL, WITHOUT AFFECTING PLANT-OPERATIONS

The Cariboo Pulp and Paper Mill in Quesnel, BC, has used enzymes since February 1992 to enhance the bleaching of oxygen-delignified kraft pu lp. Initially, xylanase enzymes were used to overcome limitations in C lO2 production capacity. More recently, the mill has not been limited in ClO2 production during ECF campaigns, and enzymes have been used to decrease bleaching costs and increase pulp quality. This paper descri bes how Cariboo achieves these benefits. This also serves as a case st udy of a mill with oxygen delignification and excess ClO2 capacity ach ieving cost savings with enzyme treatment.