Energy and chemical conversion of five Australian lignocellulosic feedstocks into bio-crude through liquefaction

Abstract

Thermal liquefaction of five potential feedstocks namely, banana bunch stems (BBS), pineapple tops (PT), Forage sorghum (FS), bagasse (Ba) and Arundo donax (AD) were examined from an energy perspective at a large laboratory scale. Comparison of oil yield and higher heating value (HHV) of feedstock and bio-crude at this scale enabled analysis of the energy efficiency of the liquefaction of feedstock with varying structural compositions under different reaction conditions. Arundo donax was used to investigate degradation behaviour for bio-crude production at temperatures between 250–350 °C and biomass/solvent ratios of 1/10 to 1/25 (wt/wt). Maximum bio-crude yield of 67.3% was observed for AD at 350 °C and biomass/solvent ratio of 1/15. Liquefaction with recycled solvent in the first run improved energy recovery and the heating value of the bio-crude in comparison with fresh solvent. On the basis of the energy conversion, the feedstocks ranked as follows: BBS (105%) > FS (77%) > Ba (57%) > PT (55%) > AD (40%). GCMS results showed that the chemical composition changed in distribution and relative abundance of the oxygenated compounds, varying significantly depending on the type of biomass. Analysis of energy input and output of varying conditions and feedstock showed energy requirements and the HHV varied with the feedstock.