Impact of raw material properties and agglomeration pressure on selected parmeters of granulates obtained from willow and black locust biomass

Abstract

Woody biomass is an very important component of contemporary energy policies in many countries. It is mainly used as a raw material for the production of compacted solid biofuels (pellets and briquettes). Biomass, due to the different origin, is characterized by high variability of parameters, which significantly affect the quality of the obtained solid biofuels. Biomass processing technologies also have a significant impact on the final product properties. Therefore, in aglomerated solid biofuel production it is very important to know the impacts of the main factors (material and process) influencing on the granutale parameters. Thanks to this knowledge, it is possible to intensify the influence of the parameters improving the product quality, as well as to eliminate those that are decreasing this quality. Mainly the quality parameters of compacted solid biofuels are connected with a density (bulk, envelope and absolute density, porosity ect.). These parameters are very important from the viewpoint of logistics processes, burning processes, etc. The results of the research were presented, the aim of which was to determine the effect of raw material fragmentation degree (willow and black locust biomass) and agglomeration pressure on the parameters of granulates. The research material was obtained by grinding the willow and black locust biomass on a mill with sieves of hole diameter 8, 6 and 4 mm. Raw material particle size distribution, porosity, envelope and bulk density have been specified. Granulates were made of material with a moisture content of 12 % on the pressing stand by compacting pressure 100, 150 and 200 MPa. Envelope density, compaction degree and index were determined for the granules.