A CFD-based comparative analysis of drying in various single biomass particles

Abstract

The understanding of the behaviour of biomass particles is important, therefore, modelling different sub-processes of biomass thermal conversion is derived during these years. This paper addresses a comparative CFD based analysis of different drying models. Several sub-models are simulated to investigate the evaporation process of different geometries based on standard densified wood pellets. In order to predict the transient evolution (moisture to dry wood) of the wood particles, transport equations (energy and moisture evaporation) are solved considering the reaction heat loss, effective thermal conductivity, specific heat capacity, and radiative and convective heat transfer. These models are compared with the previous experimental and numerical works. The Heat Sink model demonstrates the closest agreement with the reported data based on a cylindrical shape of biomass particle. This model is further analyzed by increasing the moisture content and decreasing the surface area exposed to radiative and convective heat taking into consideration the particle density, effective thermal conductivity and specific heat capacity. The results show a remarkable decrease in drying time when the particle is fully exposed to external radiative and convective heat with the lowest moisture content.