The Effect of Particle Size on the Quality and Yield of Batch and Continuous Hydrothermal Liquefaction Products

Abstract

Abstract-In this study, the effect of the biomass particle size on hydrothermal liquefaction in both batch and continuous systems is investigated. Batch and continuous hydrothermal liquefaction was done using sweet sorghum bagasse as feed across a range of particle sizes (+0 to -850µm) at a constant biomass loading (1 wt.%), temperature (280°C) and residence time (20 min). Overall is was found that particle size did not have any significant influence on the product yield or quality. The biochar and bio-oil fraction from the continuous HTL system were found to have lower yields than the batch counterparts however, the quality of these products were superior compared to the batch system. The continuously produced biochar had a quality similar to lignite coal, while the batch produced biochar quality was inferior to that of peat. The true significance of this result is that the continuously produced biochar were produced at a maximum temperature of 215°C and had a calorific value of 30.8 MJ/kg.