Comparative study on the compression characteristics of coal and biomass powder bed

Abstract

Biomass substitution for fossil energy is desirable to achieve carbon emission reductions, and the storage and transportation process of biomass is governed by its compressibility. The compression characteristics of pulverized coal, rice husk and lignocellulose were compared under mechanical and gas pressurization, respectively. The experimental results showed that the descending order of relative packing density (RPD) was lignocellulose > rice husk > pulverized coal under mechanical pressurization, while an opposite trend was observed under gas pressurization. The cohesion properties were rationally correlated with the packing behavior of powder bed, and the differences in RPD order were discussed as the higher cohesion corresponding to a larger void fraction. For mechanical pressurization, biomass had higher void fraction, which was directly linked to larger RPD. On the contrary, gas permeated easily into the biomass powder bed, and the lower pressure drop decreased the compression capacity of gas pressurization. In addition, a model for predicting the RPD was proposed with an error of ± 5 %.