Hållbar pappersproduktion : Processoptimering via datasimulering

The purpose with this work is to increase the understanding about the energy consumed in papermaking, by combining existing calculation models and calculations, that gives the outgoing moisture rate and the needed energy for unit operations, vacuum dewatering and wet pressing, as well as a model for frictions that occur when different number of suction boxes are used. The moisture ratio that becomes the best of the first dewatering and then the pressing is then the decisive factor for energy required in the drying section, to dry off the remaining water. Using the vacuum model, in the wire section, the result showed that the dewatering is not dependent on the temperature, because after the stock has travelled for a time in the wire section, the stock will have close value regardless of the initial stock temperature. Vacuum pressure levels of 30 and 40 kPa do not make a big difference during dewatering, but vacuum pressure levels of 50 and 60 kPa give a significant difference in dewatering, which is summarized by the fact that increased vacuum pressure level gives a smaller initial moisture ratio. The decreasing permeability model used in this work (press model), shows that increasing pressure results in less outgoing moisture from press section. With increased pressing pressure, vacuum pressure level becomes less important during dewatering system. The stock temperature parameter affects the dewatering in press section, that increasing temperature give less outgoing moisture. The friction energy increases with increased vacuum pressure and increased number of vacuum suction boxes, but the friction energy does not change with increased speed, which means that you can increase paper production without having to apply more energy