Effect of moisture content, forming temperature and structural components on Biocoke solidification from various biomass resources

Abstract

Biocoke (BIC) is a solid fuel made from various types of biomass resources. BIC is expected to be a coal substitute fuel because of its high density and high hardness characteristics. In a previous study, we have indicated the effects of formation conditions on BIC properties. In this study, the main structural components of biomass: cellulose, hemicellulose, and lignin, were investigated to systematically deduce the forming properties from the biomass components. The initial moisture content is a critical parameter due to the solid surface reactions by lignin in the formation of BIC. The initial moisture content affects the thermal softening temperature of hemicellulose and lignin as an adhesive of BIC. Thus, we investigate the effects of biomass components and the initial moisture content on compressive strength of BIC. The raw materials of this study were woody biomass (trunk from conifer trees and bark from conifer trees) and herby biomass (bagasse and rice straw). The result of compressive strength shows that trunk BIC has the highest compressive strength among BIC made from those biomass materials. The maximum compressive strength has a directly proportional relation to cellulose content. Due to the increase of the initial moisture content, the maximum compressive strength decreased. The maximum strength could be approximated by a quadratic curve for hemicellulose content.