Combustion of wood pellets in Fittjaveket

Fittjaverket produces heat by firing wood powder. Wood powder is a by-product from forestry industry and the incineration of this product entails no additional input of carbon dioxide to the atmosphere

At the end of 2006, Fittjaverket changed to using wood powder, instead of oil. Wood powder is the result of grounded wood pellets and is basically like firing wood. The difference to solid wood is that wood powder or pellets are three times as efficient. Pellets are manufactured from various by-products from forestry and wood processing industry, such as sawdust. The sawdust is dried and afterwards grounded in a mill, in order to receive a finer fraction. Later, the ground material is pressed at an extremely high pressure and high temperature in the matrix of wood pellets. Finally, the product is cooled down and delivered to the customer. Fittjaverket has a boiler which is equipped with 4 combined burners, built for heating oil, pine pitch oil, and wood powder. In addition, the boiler was fitted with a new smoke gas exhauster and a completely new fuel management system for pellets was installed. The pellets treatment system consists of a reception station for rear tipping trucks. From the reception station, the fuel is transported to a silo, where magnetic materials are separated. Thereafter, the pellets are brought to a mill, where four parallel lines ground the pellets to powder, which is subsequently stored in a powder silo. Eventually, the powder is dosed and blown up to the burners. The carbon dioxide, emitted during the combustion of wood powder entails no additional input of carbon to the atmosphere. Because, it was taken up by the tree during its growth and is therefore part of the natural carbon cycle. The maximum effect of burning tree powder at Fittjaverket is 140 MW.