Thermochemical Liquefaction of Algae for Bio-Oil Production in Supercritical Acetone/Ethanol

Abstract

Thermochemical conversion processes such as supercritical fluid extraction are used for producing bio-fuels from biomass. Supercritical fluid extraction process is decomposition process of lignocellulose or other organic materials thermally under supercritical conditions at 250-400 degrees C temperature range under high pressure (4-5 MPa). In this study, the supercritical fluid extraction was used to produce bio-oils from algae. Supercritical fluid extraction trials were performed in a cylindrical reactor (75 mL) in organic solvents (acetone, ethanol and isopropanol) under supercritical conditions with (ferric chloride, potassium hydroxide) and without catalyst at the temperatures of 255, 275 and 295 degrees C. The effects of process variables including temperature and catalyst on product yields were investigated. The produced liquids at 295 degrees C in supercritical liquefaction were analyzed and characterized by elemental, GC MS and FT-IR. 160, 122 and 108 different types of compounds were identified by GC MS obtained in acetone, ethanol and isopropanol respectively. Bio-oils from supercritical liquefaction were composed of various organics including aromatics, nitrogenated and oxygenated compounds. Bio-oils obtained from supercritical liquefaction were found to have higher calorific values and superior fuel properties compared to feedstock. (C) 2015 Elsevier B.V. All rights reserved.