Energianalys och kartläggning av värmeväxlarsystem i Kvarnsvedens pappersbruks massafabrik

• Main Author: Vendel, Jesper
• Format: Others
• Language: Swedish
• Published: Uppsala universitet, Institutionen för fysik och astronomi 2015
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-265039

When thermo mechanical pulp is produced refiners are used for beating wood to change the fibre structure. The refiners use a lot of electricity and generates a lot of heat. Heat which later on is recovered in a system of heat exchangers in order to be used for heating in different facilities in the mill. When the heat generated by the refiners is not sufficient to cover the heating demand steam is used to cover the needs. Over the years the mill and the heat exchanger system has faced reconstructions. At the moment there is no comprehensive picture of the system and it is uncertain if it works properly. This thesis aims to map the system and examine potential problems connected to the system. Once the malfunctions are discovered suggestions to make the system more efficient are to be made. The thesis is based on the study of four different time periods characterized by a high production of pulp. Information about the system regarding mass flows and temperatures are gathered from the mills process computers. The heat exchanger system has been studied concerning things like energy demand in its different components but also steam consumption and energy losses. The results of the study shows the importance of keeping a high temperature in the container gathering the hot water in the pulp mill. If its temperature is above 40 °C and paper machine 12 is in operation no additional steam is needed in the observed system. There are also reasons to believe the heat exchangers need to be cleaned.