Adaptive control applications in pulp and paper

Processing kraft pulp poses a set of difficult control problems, because of varying time delays in the process, an incomplete understanding of the bleaching process and lack of instrumentation. Improved control of the bleaching process increases pulp quality and reduces manufacturing costs. The bleaching process is reviewed, and its problems and existing control solutions are described. Field results from applying a new approach to bleach plant control are presented. The main result is a marked decrease in the standard deviation of pulp brightness, about 40 to 50%. This new approach involves an adaptive controller that models the process as a Laguerre polynomial