Abstract:
Hydrothermal liquefaction (HTL) is a promising process to convert biomass into liquid fuels, so called biocrude. The objective of this work was to investigate an effect of demineralization using nitric acid and hot water on the liquefaction of sugarcane leaves. Besides, the biocrude production from that process was comprehensively explored in ratio of ethanol/water co-solvent. The operating conditions, temperatures (300, 325, and 350 oC) and ethanol concentration (0 to 100 vol.%), were varied. HTL was performed in a batch reactor and a semi-continuous reactor. Demineralization treatment with nitric acid and hot water was found the effectively reducing the ash content of sugarcane leaves from 10.05 to 8.30 wt.%. The experiments were conducted in a 250 mL autoclave reactor at 300°C, with an initial pressure of 2 MPa and reaction time of 60 minutes. The results indicated that the demineralization by nitric acid at 5wt.% in pure ethanol gave the highest bio-crude yield of 45.92 wt.% while the yield of biocrude by hot water was 42.44 wt.%. The another experiments were carried out in a semi-continuous reactor at the solvent flow rate of 1.0 mL/min at 300oC for 60 minutes. The co-solvent system was found to give higher bio-crude of 32.56 wt.% by nitric acid at 5wt.% while the yield of biocrude was 21.97 wt.%. by using hot water. This indicated a synergistic effect when using ethanol-water mixture in semi-continuous reactor. The GC-MS results found that, before demineralized the biocrude contains mostly phenolic compounds and other oxygenates compounds and after demineralized the biocrude contains anhydrosugars such as Levoglucosan.