Improving product quality in pulp mill using statistical process control (SPC)

The paper describes the application of statistical process control (SPC) to enhance product quality at Slave Lake Pulp Corporation, Alberta. The Slave Lake Pulp Corporation started its greenfield bleached chemi-thermo-mechanical pulp (BCTMP) mill in December 1990. Critical pulp quality parameters, such as freeness and brightness, are entered to a computerized mill-wide information system (MOPS) by operators. The MOPS system and the SPC package was developed and supplied by MoDo-Chemetics, Vancouver. Feedback from the SPC alerts the operators to “out-of-control” data points. Corrective action is taken immediately to identify the causes. The SPC control charts have improved operator understanding of the process, and reduced the response time required to return the process to target conditions. The overall result of using SPC at Slave Lake Pulp Corporation has improved in product uniformity of brightness and freeness by 60% and 26%, respectively