Palm kernel oil fractionation using supercritical fluid extraction (SFE) technology

Abstract

A study was conducted to evaluate the performance of palm kernel oil fractionation process using supercritical fluid extraction (SFE) pilot plant at maximum loading capacity of 25 L. The experiments were carried out using 5 kg of grinded palm kernel samples. Various critical pressures of carbon dioxide (CO2) at 30, 35, 40 and 45 MPa were operated at constant temperature of 80 °C. The extraction time was set at 6 hours to ensure completion of the palm kernel extraction process. Grab sampling of fractionated palm kernel oil were taken using time based method. The samples were analysed for fatty acid composition (FAC), free fatty acid (FFA), moisture, dirt, and iodine value (IV). The results showed that lauric acid C12 content had reduced while the oleic acid C18:1 content had increased significantly for testing at 30, 35, 40 and 45 MPa, respectively. The highest reduction of lauric acid and the highest increase of oleic acid were recorded when operating the critical pressure of carbon dioxide (CO2) at 35 MPa. This was supported by the lodine Value (IV) reduction following the reduction of lauric acid content. The FFA had reduced along the extraction process in the range of 30-35% from the original FFA content. The moisture and dirt contents recorded much lower results than that of crude palm kernel oil extracted using mechanical method though slightly higher than RBDPKO quality. It is concluded that the SFE technology can be used to conduct palm kernel oil fractionation and the quality of extracted palm kernel oil was much superior than the mechanical extraction method. However, the refined oil quality targets in term of colour, %FFA and odour are yet to be achieved.