Dynamic simulation and control of a paper machine wet end

A good simulation model for paper machines can be used to identify deficien cies in the design, bottle-necks during operation, and regions of poor cont rol. It also allows users to test their hypotheses and innovations without potentially causing major upsets and reducing throughput. In this work, a d ynamic model of the wet end system has been developed using the IDEAS(TM) p latform, describing the distribution of fines, fillers and fibres throughou t the system. The model was then tested at steady state with mill data for the low-ash and high-ash production grades, and the results show that over 70% of the predicted values had only 5% deviation. The dynamic simulation w as also used to show that the retention aid controller would react in the w rong direction due to changes in the wire pit consistency and the stock rat io would cause major changes in stream compositions and consistencies of th e wet end.