Improvements on Semi Critical Assisted-Solvent Extraction of Biocrude Oil from Spirogyra. sp Macro Algae

Abstract

Here, we report on an improved chemical method to extract hydrocarbons (CH) and Fatty Acid Methyl Esters (FAME) from wild green macro algae, which is higher than that carried out with conventional Soxhlet (Sx) and similar to that of Subcritical (SbC) or supercritical fluid (SCE) extraction methods. Crude oil plus residual biomass gave combined calorific values of 49.05 MJ/kg in agreement with its high-detected hydrocarbons (C, 72.56%; H, 10.59%) as desired for high quality liquid fuels. Oil extraction from macro algae was improved from 13.2% (Sx) to 34.8 % under Semi Critical Assisted-Solvent (SmCA-Sol) conditions. The extraction improvements are associated with an upgraded glassware design that works than in continuous or step-by-step operation under mild or high temperatures (<40, >500°C) as well as under moderate vacuum to above 1.0 atmosphere of pressure. The SmCA-Sol method creates a dynamic steam/solvent phase which exposes algae cell matrices to percolation in two opposite pathways leading to high yields of biomass extraction whether compared with traditional methods. Factors governing cell wall activation under SmCA-Sol conditions are discussed and compared with those carried out using advanced technologies and make recommendations towards future research regardless of macro algae chemical extraction of hydrocarbon and lipids.