(772e) Effect of Process Parameters and Extractive Solvents on Hydrothermal Liquefaction of Microalgae

Hydrothermal Liquefaction processes proves to be an attractive technology from the view point of energy consumption, renewability and process integration for converting wet biomass into energy dense bio-oil. The yield and quality of bio-crude oil is influenced by process conditions like liquefaction temperature, solid-loading ratio, residence time, type of solvent for extraction. Therefore, we investigated the influence of these parameters on the hydrothermal liquefaction of microalgae Micractinium sp. The temperatures and solid-loading ratios were varied from 200 to 350°C and 0-20 % respectively in a stainless steel batch reactor. Experiments were also performed with residence times varied from 0 to 60 minutes (~15 minutes interval). The maximum bio-oil yield was obtained at 300°C and at a solid loading ratio of 10 % for 30 minutes residence time. Experiments were performed with different solvents including hexane, acetone and dichloromethane for the separation of bio-oil from product phase. Energy recovery calculations were performed with the analysis of the products (bio-oil, biochar, water soluble compounds, and gaseous phase) through ultimate and proximate analysis. Products were also analyzed by Gas Chromatography Mass Spectrometry (GC-MS) and calorimetric techniques.

Keywords: Microalgae, Hydrothermal Liquefaction, Renewability, Bio-oils/fuels, GC-MS