The effect of hemicellulose on the interparticle frictional behavior of lignocellulosic biomass particulates

Abstract

Lignocellulosic biomass material sourced from plants and herbaceous sources is considered as a prospective feedstock of inexpensive, potentially carbon-neutral energy. Lignocellulosic biomass is structurally built on cellulose, hemicellulose, and lignin, which are present in varying concentrations based on the feedstock type and play distinct and not well understood mechanical functions in the flow behavior. The frictional characteristics of lignocellulosic biomass particulates influence their flow behavior in biorefineries. Thus, it is important to fundamentally investigate the relative contribution of cellulose, hemicellulose, and lignin to the frictional behavior. However, these three biopolymers are interwoven into a complex matrix in the lignocellulosic biomass, thus making it hard to quantify the contribution of each biopolymer. In this study, we selectively remove hemicellulose from switchgrass and investigate the effects of its diminishing concentration on the coefficient of friction.We observed that the angle of repose and, therefore, the coefficient of friction for a loose assembly of the control and treated switchgrass samples decrease with decreasing hemicellulose content. This indicates the frictional resistance to flow for biomass particulate assemblies is at least proportional to the hemicellulose content. We also established that the observed changes in the frictional behavior were not due to particle morphological characteristics.