Extraction of rice bran oil using supercritical carbon dioxide and propane

Extraction of rice bran lipids was performed using supercritical carbon dioxide (SC-CO2) and liquid propane. To provide a basis for extraction efficiency, accelerated solvent extraction with hexane was performed at 100 degrees C and 10.34 MPa. Extraction pressure was varied for propane and SC-CO2 extractions. Also, the role of temperature in SC-CO2 extraction efficiency was investigated at 45, 65, and 85 degrees C. For the SC-CO2 experiments, extraction efficiencies were proportional to pressure and inversely proportional to temperature, and the maximal yield of oil achieved using SC-CO2 was 0.222 +/- 0.013 kg of oil extracted per kg of rice bran for conditions of 45 degrees C and 35 MPa. The maximal yield achieved with propane was 0.224 +/- 0.016 kg of oil per kg of rice bran at 0.76 MPa and ambient temperature. The maximum extraction efficiencies of both SC-CO2 and propane were found to be significantly different from the hexane extraction baseline yield, which was 0.261 +/- 0.005 kg oil extracted per kg of rice bran. A simulated economic analysis was performed on the possibility of using SC-CO2 and propane extraction technologies to remove oil from rice bran generated in Mississippi.. Although the economic analysis was based on the maximal extraction efficiency for each technology, neither process resulted in a positive rate of return on investment.