Simulation and process design of continuous countercurrent ethanolic extraction of rice bran oil

The overwhelming majority of all vegetable oils is extracted using solvent extraction, and the most widely used solvent is hexane. However, the use of ethanol has attractive advantages, including low toxicity, good operational security, as well as being obtained from a biorenewable source. In this study, a multiple-batch solid-liquid extraction system has been successfully employed to simulate continuous countercurrent ethanolic extraction of rice bran oil. Results showed that the extraction process using ethanol as solvent is feasible and facilitated by increases in temperature. The number of equilibrium stages required for rice bran oil extraction was theoretically determined, and it was shown that in the extraction process using hexane the number of ideal stages is lower than the number required when ethanol is used as solvent. Furthermore, a mathematical expression for determining the minimum flow of solvent depending on the equilibrium relationship between the extract and raffinate phases has been developed and implemented for both solvents. Given the potential fire hazard and harmful emissions risks of using hexane as solvent, extraction with ethanol showed to be a promising alternative to conventional extraction, completely exhausting the solid matrix with only five stages.