Economic evaluation of the production of oil extracted from pressed sesame seed cake using supercritical CO<inf>2</inf> in Thailand

Abstract

The optimal condition for extracting sesame oil from pressed sesame seed cake using supercritical CO2, previously determined as an extraction temperature of 50 °C, extraction pressure of 220 bar and extraction time of 5 h to obtain the optimal extracted oil yield of 29.8% dry basis, was used to estimate the scale-up and cost of a supercritical CO2 extraction plant. Economic evaluation of the process for extracting oil from pressed sesame seed cake using supercritical CO2 was determined using two 360 L volume extraction vessels with an internal diameter of 0.43 m and height of 2.5 m, a CO2 density of 806.61 kg/m3, a CO2 flow rate to feed mass ratio of about 282.31 kg CO2 per kg feed and a bed diameter (D) to bed height (L) ratio of 0.17. The result showed that the total estimated capital investment required to establish a supercritical CO2 extraction plant with a capacity of 250 tons per year is 80.25 million Baht and the estimated manufacturing cost is 20.78 million Baht per year. The production cost is approximately 277.03 Baht per kg of oil and the selling price of extracted sesame oil is approximately 500 Baht per kg of oil. Thus, the net profit is 16.72 million Baht per year. As a result, the rate of return on investment and the payback period are 20.84 % and 3.56 years, respectively. The sensitivity analysis showed that the profitability of supercritical CO2 extraction plant is highly dependent on selling price and annual production of the extracted sesame oil product. The results imply that the proposed up-scaled supercritical CO2 plant is economically feasible.