Model Based Control of High Consistency Refining, 1995 Pulping Conference Proceedings

B.C. Strand

Pacific Simulation

A model based refiner control system has been implemented at Ponderay Newsprint Co. in Usk, Washington on two lines of high consistency refiners producing newsprint quality TMP. The control system uses factor network analysis to predict refiner blowline consistency on-line, in real time. The blowline consistencies are then controlled using refiner dilution water. Since implementation, the control system has reduced variations in refiner consistency by approximately 40%. The mill has also recently installed a pulp quality system for on-line measurement of freeness, fiber size distribution and shives. This information is presently being integrated into the consistency control system and will allow the control system to monitor and control freeness and fiber size distribution. Also planned is an energy optimization system which will be used to reduce the specific energy required to reach a given pulp quality.