Making biodiesel with SC methanol

A team from the School of Chemical Engineering, Universiti Sains Malaysia (Penang; www.eng.usm.my) has carried out a study for optimizing non-catalytic supercritical (SC) methanol extraction and transesterification of Jatropha curcas seeds to produce biodiesel fuel. Jatropha curcas is a species of flowering plant native to the American tropics. The seeds contain up to 40 wt.% oil that can be processed to produce high-quality biodiesel fuel. Several methods for processing the plants oil to produce biodiesel have been developed. The team says its method promises to be superior to conventional biodiesel processing regarding reaction time, product separation, fatty acid methyl ester yield, and process integration. It used a high-pressure batch reactor with n -hexane as a co-solvent. Methanol was selected due to its mild supercritical condition (513.15K, 8.1 MPa) and low boiling point (338.15K) for easier separation. At higher temperature and pressure (300°C and 24 MPa), the extraction of oil from the seeds was more efficient than in the case of conventional oil extraction, either with chemical solvent or mechanical pressing. Also, no catalyst was required, which greatly simplified downstream processes such as catalyst separation and…