Transition control of paper-making processes: paper grade change

Grade change on a paper machine is a transition from one set of operating conditions to another. During the transition, without proper coordination and control, the entire process could have radical fluctuations and produce significant amounts of off-spec paper or even cause sheet break. The production loss and the efforts to recycle off-spec waste are very costly. To address the issue, this paper formulates the dynamic models of paper-making processes and presents an effective control of grade change transitions. The method has been applied to several hundreds of paper machines. A real application example is included here to demonstrate the actual performance of the described approach.