Experimental and numerical analysis of the effect of compaction conditions on briquette properties.

This paper determines the effect of compaction process parameters such as compressive stress, process temperature and biomass moisture content on the density of the resulting briquette, its compressive strength, Young's modulus, relaxation, process energy consumption, and the work needed for densification. The research material was pine sawdust from the forests of Puszcza Zielonka located in the west-central region of Poland which was dried to the moisture content of 20% and 10%. It was subjected to the loading–unloading process and the triaxial compression process, and the resulting briquette was subjected to axial compression and shear. The values of the friction coefficient of sawdust against steel – the material of the compaction assembly elements – were determined. The experimental research made it possible to determine the best values for the compaction process parameters in order to obtain the optimal properties of briquettes, taking into account their transport and storage as well as application as an biofuel. The highest strength of the briquette was obtained for the compressive stress of 150 MPa, temperature of 150 °C and sawdust moisture content of 10%. The research enabled the creation of the numerical model for the compaction process using the Drucker-Prager-Cap model. The simulation model and its experimental verification made it possible to reflect the characteristics of changes in compaction force, energy consumption and density, which makes it useful in the context of simulating the compaction process without the need to perform experiments. It also enables the formulation of guidelines for newly developed designs of compaction machinery working units. [ABSTRACT FROM AUTHOR]