Development of separation technology for valuable oil mixture of citrus juice waste

The juice processing waste of citrus fruit has high potential because it contains valuable hydrocarbons such as essential oils and triglyceride derived from peel and seed, respectively. In this work, the separation of limonene and triglycerides from the oil mixture as a model waste of citrus fruit by using supercritical carbon dioxide (SC-CO₂) was performed at temperatures of 30 - 65 °C and pressures of 7 - 30 MPa. Two modes of separation apparatus were applied. At first, the mixed flow separation apparatus was used to investigate the tendency of separation behavior. The result showed that the yield of extract increased with increasing operating pressure. However, the triglyceride and limonene components could not be properly separated at each operating temperature. Next, the continuous experiment was carried out using a countercurrent separation method. It was observed that the extract and raffinate have been fractionated in a stable amount at 180 min. The result showed that the limonene content and its recovery rate were 95.04 % and 90 % at 30 °.C and 10 MPa, respectively. Furthermore by applying the temperature gradient in the fractionation column, the limonene component was concentrated more effectively.