Enhanced production of hydrocarbons from lignin isolated from sugarcane bagasse using formic acid induced supercritical ethanol liquefaction followed by hydrodeoxygenation

Abstract

This study involves the production of hydrocarbons from lignin extracted from sugarcane bagasse using Hydrothermal Liquefaction (HTL) followed by Hydrodeoxygenation (HDO). HTL of the lignin was studied under different solvents-methanol, ethanol and isopropanol in the presence of formic acid as an effective H-donor under varying lignin to solvent ratios (L:S = 1:15,1:30,1:40 g/mL), reaction temperatures (200 °C - 320 °C), reaction times (15, 30, 45,60 min) and ZnCl2 catalyst concentrations (30, 40, 50, 60 wt%). A maximum of 86% lignin derived phenolics was obtained when ethanol was used as solvent at 250 °C under L:S = 1:30 at 30 min reaction time with 60 wt% ZnCl2. The lignin-oil was upgraded by HDO process in the presence of Ni/Al2O3 catalyst and a maximum hydrocarbon yield of 73.5% was obtained with a HHV value of 48 MJ/kg. The hydrocarbons had excellent properties with a carbon range of C6–C12 with a purity of 51.2%.