Modeling of Densification of Biomass Grinds using Discrete Element Method by PFC

Biomass feedstocks are densified to facilitate easy handling, transportation and storage. Densification is a process of transforming loose biomass into highly densified form by the application of mechanical pressure. The mechanism involved in the process of densification is difficult to understand from existing information. A comprehensive understanding of the densification process for biomass can be attained if a modeling study is conducted. Since no existing compaction models are available to explain the process of densification of biomass, a numerical model was developed using Discrete Element Method (DEM). The main objective of this research was to apply DEM to study the compaction characteristics of biomass during densification. The DEM is an explicit numerical method of modeling the dynamic behavior of particle-particle and particle-wall interactions, and force-deformation relationship during compression. In order to develop a compaction model, a cylindrical geometry (boundary) with biomass particles inside the geometry was developed using Particle Flow Code in 3-Dimension (PFC) software package. The specific properties of biomass particles such as particle size distribution, particle density, particle stiffness, particle-particle friction, and particle-wall friction were incorporated into the model. A simple contact bond model was developed to produce the compacted mass. The model will be validated with experimental results.