Mechanical-thermal modeling oriented to the design of a compaction chamber for densification of residual biomass

Abstract

The energy transition requires efforts oriented in multiple directions to achieve the sustainable exploitation of the largest amount of renewable energy sources available. Of particular interest for countries located in warm regions and with favorable soil conditions is the use of residual biomass from agricultural and forestry crops. This renewable source of energy has the disadvantage of its low apparent density when it leaves post-harvest processing systems, being necessary its densification to achieve an energy density attractive in economic terms. This article presents the mechanical and thermal modeling of a compaction chamber of a briquetting machine oriented to the design of an experimental prototype. The internal and external diameters of the compaction chamber are considered as independent variables and, as a response, the heating time to achieve a temperature in the biomass, to achieve the activation of the lignin. The preceding, keeping constant the electrical power installed in the compaction chamber, stroke length, compaction pressure, materials choice, among other geometric factors. Finally, a search is made for the minimum use of material for the compaction chamber subject to a condition of mechanical strength and a fixed electrical heating power. As a result of the study, the best geometry of the compaction chamber is obtained to achieve the minimum use of material, ensuring the shortest heating time, and meeting the goal of permissible design stress. This work can be useful as a guide for the optimal design activity of compaction chamber in biomass densification equipment.