Energy Efficiency of Conifer Cones and Seed Extraction Residue Biomass

Abstract

Sustainable forest management, which accounts for the multiple roles played by forests, includes seed collection from selected areas for forest renewal and regeneration. The process of harvesting conifer seeds generates considerable amounts of waste biomass that can be used as a source of energy to supplement the local solid fuel market. Therefore, their quality is an important consideration. The mass fraction of Scots pine seed extraction residues was determined in this study. The thermophysical properties and elemental composition of the residues and spent Norway spruce and European larch cones (after seed extraction) were evaluated. An analysis of Scots pine seed extraction residues revealed that only cones had practical application. They accounted for more than 99% of total residue biomass and were characterized by the lowest content of ash, sulfur, and chlorine. The calorific value of cones of the analyzed tree species ranged from 17.08 to 18.29 MJ kg−1, the chlorine content was 0.010–0.041% DM, and the sulfur content was 0.019–0.043% DM. Due to the specificity of the extraction process, the generated waste, including cones, had a very low moisture content of 6.86–10.02%, which significantly increased their value as solid fuel.