High pressure extraction of oil seed

For calculation of phase equilibria of the system seed oil/CO₂, an equation of state published in the literature has been fitted to experimental data of that system. The results thus obtained are of only limited use in designing a supercritical extraction process. The experimental investigation of the mass transfer kinetics is much more significant. Mechanical processing of the oil seed’s cell wall structure has been shown to be of great importance. The best specific yields were achieved with material that had been mechanically pre-deoiled and thereby broken open. Yields are increased considerably by use of the gas mixture CO₂/propane or other special gas mixtures or by the addition of refrigerants. However, the extraction times achieved in batch operation, together with the mass product nature of oil seed, make a continuous supercritical extraction essential if operation is to become economic relative to the conventional hexane extraction. To this end, the energetics of the process have been calculated, and practical possibilities for continuous operation are discussed. Presented at the International Symposium, “High Pressure Chemical Engineering,” Erlangen, in October 1984.