Technical-Economic Study of the Esterification Process of Used Vegetable Oils (UVOs) using Heat Exchange Networks (HENs)

Abstract

The objective in this study was to conduct a technical-economic study of theesterification process of used vegetable oils (UVOs) for the production of biodiesel from the pointof view of energy savings achieved by implementing heat exchange networks (HENs). Usedvegetable oils (UVOs) can be employed as an input in the production of biodiesel by catalytictransesterification. But, previously it is necessary to reduce its level of free fat acids (FFA) by theacid-catalyzed esterification process in order to prevent undesirable saponification reaction. Tocarrying out an optimal design of the technology required in the process, simulation tools have animportant role for process engineering and optimization of resources. Computer programs such asAspen Plus and Aspen Energy Analyzer provide an environment to perform process modelingand network design optimal heat exchange. In this paper, from the Aspen Plus simulation of theprocess of catalytic esterification in acid medium of UVOs, the technical-economic evaluationprocess was conducted with and without network of heat exchange in order to analyze the differentinvestment options. The comparison of the two projects (with and without the implementation ofHENs) was performed by determining the net present value (NPV). On the scale set for the project,the total cost of the equipment of heat exchange for the esterification process designed with HENswas US$ 4,782.50 higher than the corresponding to the process without HENs application.However, it should be noted that the cost of services decreased by 30% annually, and on the otherhand, comparing the process, it was observed that the NPV of the HENs process was 29.5% higher,which leads to the conclusion that the project which includes heat exchange networks is technicallyand economically feasible.