Mathematical Modelling of Pressure Distribution along the Die of a Biomass Briquetting Machine

Abstract

The screw extruder briquetting die is critical to determining the quality of biomass briquettes. In this study, mathematical models were developed to study pressure distribution along the briquetting die using the hot extrusion scheme and assuming a plug flow. Parametric analysis to determine the effects of design variables on die pressure distribution was carried out by simulation using developed mathematical models. Results showed that pressure along the die entry decreases rapidly with high yield strength of compacted biomass and with increased friction coefficient at the briquetting die interface. As friction coefficient at the die interface increases, there is rapid decrease in pressure along the length of the die. Parameters resulting in rapid pressure decrease along the briquetting die length would result in increased die pressure at the end of the screw extruder. The developed mathematical models and the results obtained could significantly contribute to design of briquetting dies.