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1  Department of Biosystems Engineering, Institute of Mechanical Engineering, Warsaw University of Life Sciences – SGGW


The principles of rational management of residues from forest production recommend the use of logging residues, including for energy purposes. The shredded material can undergo compaction to increase the energy value and improve its physical properties This idea is a manifestation of innovation in the world of technology and efforts to protect the natural environment.

It should be remembered that inhomogeneous physical properties of the raw material, and its structure and composition can cause serious problems in its further use. As a result of the research, it was found that the elemental composition of logging residues (low nitrogen and ash content) is suitable for energy raw materials. The correlation between the physical properties of the produced briquettes and the parameters of the raw material subjected to the briquetting process was also determined. The biomass was compacted in a closed chamber at unit pressures of about 60 MPa. The material to be compacted was forest chips with a moisture content of 10, 15, 20%, the process temperature was22 and 73°C. For both temperatures, the best results were obtained for a material with a moisture content of 10%. It was found that the temperature of the chips during agglomeration influences the degree of compaction and durability of the obtained briquettes, and that agglomeration carried out at a higher temperature gives better results. The study also determined the impact of the fractional composition of the briquetted mixture, its humidity and the temperature of the agglomeration process on the durability of the product. The raw material under examination were divided into four independent groups with dimensions: 0 – 1, 1 – 4, 4 – 8 and 8 – 16 mm. The most favorable fractional composition of the briquetted mixture, its moisture and the temperature of the compaction process were determined. The mixture, from which the most durable briquettes were made, contained 50% of fraction 0 – 1; 15% of fraction 1 – 4 and 25% of fraction 4 – 8. Its humidity was 15% and the process temperature was 73°C.

Keywords: forest; biomass; pressure; agglomeration; briquette; durability; logging residues