Energibalanser på och miljöanalys av Mörrums Bruk - med speciell betoning på energieffektiv och miljöriktig användning av barköverskott

At Mörrums Bruk a Kraft pulp mill, which belongs to Södra Cell group, a new BFB boiler was planned to be taken into operation during 2002. A new EU-directive, which forbids continued depositing of biological waste, makes burning the waste in a suitable boiler the only option. The new boiler was designed to increase the steam production to meet future increases in pulp production. Also a reduction of the environmental load of operating the steam boiler was a goal. To investigate how the boiler probably will perform this study, as a diploma work, was done. Actually some measurement data were available from test operation of the boiler at the end of the work. A site energy balance concept was developed, where all energy carrying input/output streams were considered. As a reference the situation during 2000 was used. To foresee the performance of the new boiler a computer model in Extend was created, with which the influence of important parameters under different operating conditions could be studied. The use of excess bark was also examined. From this study it was possible to conclude that the installation of the new steam boiler would be mainly positive. The optimal use of the excess bark is to sell it to a municipal CHP-plant. However if all the bark was to be used a new condensing turbine with a power of 5.5 MW should be installed. This increase in electricity production capacity makes Mörrums Bruk a net producer of electricity, which is economically favorable due to expected increase of electricity prices