Techno-Economic and Sensitivity Analysis of Biodiesel Production Using Co-Solvent

Abstract Three different continuous homogeneous alkali-catalyzed, heterogeneous alkali-catalyzed and supercritical methanolysis processes with adding tetrahydrofuran as a co-solvent to produce biodiesel from virgin vegetable oil were designed and simulated. An economic assessment was also performed based on the results of the process simulations. Technical assessment of the proposed processes showed that the homogeneous and heterogeneous alkali-catalyzed processes were the simplest with the least amount of process equipment, while for the supercritical methanolysis process; it was more complex with larger sizes of transesterification and separation units. The homogeneous alkali-catalyzed process using tetrahydrofuran was found to have the lowest total capital cost ($2.32 million), the highest aftertax rate of return (513%) and the payback period (0.19 year). However, total manufacturing cost and aftertax net profit, the heterogeneous alkali-catalyzed process using tetrahydrofuran had the lowest operating cost ($82.20 million) and the highest aftertax net profit ($18.20 million). The homogeneous alkali-catalyzed process I is not only technically feasible but also economically viable. Results from the sensitivity analyses indicated that methanol recovery percent, biodiesel purification tower vacuum pressure, price of feedstock oil, price of methanol, price of biodiesel and price of glycerin by-product were the factors that most significantly affected the economic feasibility of biodiesel production.