Pilot Scale Study of Vegetable Oil Extraction by Surfactant-Assisted Aqueous Extraction Process

Abstract

A number of aqueous extraction processes (AEP) have been studied as substitutes for hexane in oilseed extraction. In our previous batch-scale work, we have shown that the aqueous surfactant-based method could effectively extract up to 95% peanut and canola oils at 25°C. The goal of this work is to perform a semi-continuous pilot-scale study of the aqueous surfactant-based method for peanut and canola oil extraction. Two extraction strategies were evaluated including (1) a single extraction stage by aqueous surfactant solution and (2) two extraction stages, consisting of one aqueous surfactant wash and one de-ionized water wash. At optimum conditions, 90.6% and 88.1% oil extraction efficiencies of peanut and canola oil, respectively, were achieved in a single-stage extraction, while 94.5% and 92.6% were achieved in the two-stage extraction. At the highest solid/liquid centrifuge speed, the moisture level in the extracted meal was 48%. At the optimum liquid/liquid centrifuge condition, more than 90% of the oil was recovered as free oil from the extracted-oil and surfactant-wash mixture and 39–44% of the oil was recovered from the extracted oil and DI wash mixture. Total free oil recovered after the two-stage extraction was 87.1% and 85.6% for peanut and canola, respectively.