Economic perspectives on quality control in TMP refining processes

Artikel i vetenskaplig tidskrift, 2008

Many Studies have been carried out with the goal of improving pulp quality control in TMP refining processes. While it is intuitively clear that minimizing the deviations from the target quality is desirable, the economic value Of Such reduced quality variations is complicated to estimate. So far not much research has been done in this area related to the pulp and paper industry. This Study has been performed to address this issue and to increase the knowledge, in economic terms, of the different mechanisms involved. The focus lies in controlling the pulp quality stability of the refining stage. Several areas in which economic benefits arise from improved quality control are analyzed in more detail. A generic model for estimating the economic Value of improved quality optimization is developed. Applied to freeness variability reduction, the model indicates notable economic savings, partly in terms of energy. The connection between pulp quality variations and web-breaks in the paper machine has been Studied in a full scale trial. The results indicate that a reduction of web breaks may yield a significant contribution to the profit. Improving the quality control may also enable a production rate increase. In this case there are some energy savings due to improved refiner efficiency at higher throughput. The major economic profit contribution from production increase does however come from the additional Volume of paper.