Torkning av flis med restvärme
Metoder för att sänka återledningstemperaturen
The purpose of this study has been to evaluate whether a Low temperature bio-mass dryer could be integrated with the local district heating system in Malå. The aim is to increase the thermal efficiency of the cogeneration plant in Malå, by lowering the temperature of the cooling medium. Another benefit that comes from this is improved combustion efficiency at the power plant, since drying the fuel causes an Increase of the heating value.Simulations has been made in Excel, and with use of linear regression, to find out if it is profitable. Data for this purpose has been supplied by the power company Skellefteåkraft and furthermore SMHI.The result of the Calculations shows that a very efficient bio-mass dryer is needed, if yield of investments should be made possible. An Investment of 4,27 Mkr, in a dryer, could at a such criterium return 60000 kr/year, if the price of the biomass is 190kr/MWh. Furthermore this also demands that the time of instalments is set to 25years, and that electrical power can be used at the cost of 0,30kr/kWh.Calculations also shows that it could be quite profitable, If wood chips instead were to be made, with use of the Bio-mass dryer. In a such case the income could be 2,5 Mkr/year even if the investment of the dryer would be 10 Mkr. This demand that the time of instalments is set to 25 years and that biomass can be purchased at he cost of 170kr/MWh.