Epsilon Open Archive

Abstract

Primary residual forest biomass is an important source of energy in Sweden. The fuel quality of this biomass depends on several factors including its moisture content, ash content, and particle size distribution. Forest biomass terminals provide diverse services to the forest industry, including buffer storage, transfers of material between different modes of transport, and raw material upgrading. To design efficient terminals, it will be essential to understand the current state of forest terminals and the activities that occur within them.

The overall objective of the work presented herein was to obtain a general overview of the current state of forest biomass terminals in Sweden and to determine fuel quality parameters for five different assortments. Terminals were characterized in terms of their area, volume of material handled, equipment, inventory methods and age. The information required for this characterization was acquired by sending a questionnaire out to companies operating forest terminals that handle energy assortments in Sweden.

The properties of the 246 terminals varied widely. In general, the most pronounced differences were observed between terminals with areas of <5 ha and those with areas of >5 ha. Terminals of <5 ha accounted for 65% of the country’s total terminal area, and more than half of the country’s total forest biomass output was handled at terminals of <2 ha. Comminution was performed at 90%
of all terminals.

The chip quality measurements showed that chipped logging residues (tops and branches) contain a high proportion of fine particles (<3.15 mm), amounting to around 17% of the chips’ oven dry (OD) weight. Fines accounted for only 5.3-5.8% of the oven-dry mass of the other assortments, such as bundled tree-parts and roundwood. By screening these fine particles, it was possible to reduce the assortments’ average ash content (AC) to 0.66-2.17% (corresponding to a 20-31% reduction of total AC). Screening could thus be used to divide a chipped material
into a number of quality classes for different applications and with different prices.

This thesis provides a detailed overview of Sweden’s forest terminals and fuel quality improvements that could be achieved by biomass screening at terminals.