Energioptimering vid Kvarnsvedens pappersbruk

Sammanfattning: The paper industry is a highly energy consuming process which also facing huge challenges as the global demand of paper products constantly decreasing. Therefore, the importance of energy optimizing the process becomes more and more crucial. The purpose of this work was to contribute to the energy optimization work at Kvarnsveden paper mill in Borlänge by mapping the energy consumption and analyzing particular areas with potential of optimization. Furthermore, analysis of the process parameters tinting colors, moisture profile and the pulp refiners in order to decrease the material losses were performed. The results from the analysis of tinting colors and moisture profiles provided the operators with reference intervals which stated how to run the parameters in order to produce paper of approved quality. The purpose of analyzing the refiners was to investigate if the quality of the mass could be predicted by specific energy instead of Freeness and average fiber length, which is the method used today. The result of this analysis shows that this is not possible today. However, specific energy is a valuable parameter in order to predict process malfunctions. The result of the energy mapping shows that the total specific energy consumption to produce one ton paper is 4,1 MWh/ton. Furthermore the energy mapping shows that every ton of paper that doesn’t clear the quality control and has to be re-produced consumes additional 1,3 MWh/ton of energy, which means that the total amount of energy for reproduced paper is 5,4 MWh. The amount of energy that is necessary to re-produce shows the importance of producing quality approved paper the first time, and since PM12 is capable of producing 1 ton/min at normal operating speed, the amount of paper that has to be re-produced can increase very fast. Hopefully, the results from the analysis of tinting colors and moisture profile will contribute to a decreased amount of papers that has to be re-produced. Furthermore the energy mapping shows some areas with energy optimization potential. Partly by maintenance and repairs of heat exchangers and steam condensers and partly by terminate the heating of buildings that has no use in the production today.