Simulation of Esterification-Transesterification of Waste Cooking Oil to Produce Biodiesel using Ultrasound Assisted Integrated Double Column Reactive Distillation

Abstract

There are some problems arising related to the utilization of fossil-based fuel due to the diminishing of oil reserves. Therefore, energy transition toward the development of new and renewable energy has been set in Indonesia. Biodiesel is a promising renewable energy resource which can be synthesized from vegetable oils as feedstock via transesterification reaction. Waste cooking oil (WCO) is among the economical and abundant raw materials for biodiesel production. It contains triglyceride and free fatty acid (FFA) of 78.16% and 21.84%, respectively. Biodiesel preparation is generally carried out using conventional batch or continuous mixed flow reactors. This configuration encounters challenge related to the high cost for setting up the separation process. To overwhelm this drawback, it is essential to develop reactor which integrates the reaction and separation process. In this work, a novel design of Ultrasound Assisted Integrated Double Column Reactive Distillation (UAIDCRD) was introduced and simulated for biodiesel preparation through a coupling esterification-transesterification reaction. The first column was applied the esterification of Simulation of UAIDCRD for biodiesel production was conducted using ASPEN Plus v10. Model thermodynamic selected for the simulation was UNIQUAC. Sensitivity analysis was performed to examine the effects of reflux ratio, bottom to feed ratio, and methanol to oil ratio on the reaction conversion. Reflux ratio was studied at the range of 0.5 - 200, bottom to feed ratio was evaluated at the range of 0.25 - 0.9, and methanol to oil ratio were 1:3 - 9:8. It was observed that 99.99% reaction conversion in the esterification column was achieved with the reflux ration, bottom to feed ratio, and methanol to oil ratio of 0.5, 0.5, and 4.1, respectively. On the other hand, 99.99% reaction conversion in the transesterification column was obtained with the reflux ration, bottom to feed ratio, and methanol to oil ratio of 0.5, 0.5, and 3:1. The alcohol needed for the esterification and transesterification reaction were much lower than those required for the reaction using conventional reactor.