Wpływ technologii pozyskania i składu zrębków leśnych na ich wartość opałową i zawartość popiołu

Wood chips composition and abundance of the impurities affecting the ash content are parameter of the chips quality that is important for the power plants. These parameters may be used as criteria in settlements between the supplier and the chipmaker. The determination of calorific value, ash content and share of individual elements in forest chips was undertaken. The wood chips obtained from the fragmentation of sawmill wastes and forest trees residues with various species compositions (Scots pine, multi−species and bundled Norway spruce residues) were investigated. The linear relationship between the ash content and the calorific value of the chips was determined. In all cases, the largest share (over 87%) in the composition of forest chips is assigned to the clean timber and wood particles with bark. The share of mineral impurities is within the range of 0.6−1.6%. The ash content in wood particles ranges 1.04−3.94% and is close to the values reported in the literature. In terms of ash content, the chips produced from bundled coniferous residues were the worst. The obtained results indicate that the best technology for obtaining high calorific value of dry wood chips (17.89−18.11 MJ/kg) with a low proportion of ash is the chipping of wood residues collected directly from the forest surface or from previously prepared piles. The least advantageous technology is the bundling of residues and their storage for several months (16.29 MJ/kg).