Solubility Characteristics and Selective Extraction of Jatropha Oil by Super- and Subcritical CO₂ Extraction

Abstract

With the aim of promoting bio-fuel production technologies, particularly those using bio-oil as a fuel for thermal power generation, we have developed a technique for bio-fuel extraction from Jatropha. The selective extraction of triglycerides from Jatropha seeds (a mixture of moisture, free fatty acids, and phosphorus) is required for developing new less-costly processes that avoid the oil refining treatment typically used in conventional technologies. The solubilities of Jatropha oil in super- and subcritical CO₂ were measured, and the potential of CO₂ to selectively extract triglycerides from Jatropha seeds by controlling the extraction time was revealed. The Jatropha oil extraction experiments were carried out under both super- and subcritical CO₂ conditions using a flow-type apparatus. The amounts of Jatropha oil extracted by supercritical CO₂from 35 to 50°C were a little bit larger than the amount by subcritical CO₂ (25°C). Judging from the experimental data of the composition of the extract, subcritical CO₂ has a potential to extract triglycerides from Jatropha seeds selectively by controlling the extraction time.