Optimization of Biodiesel Production from Used Cooking Oil: Aspen HYSYS Simulation and Experimental Validation

Abstract

Due to the awareness of adverse effects of conventional fuels to environment and the frequent rise in crude oil price, the need for sustainable and environmentally friendly alternative source of energy has gained importance in recent years. This alternative has been identified to be biofuel, one of which is biodiesel. As such, this work was carried out to contribute to the development of biodiesel. The aim was accomplished by employing Design Expert, based on the chosen operating factors (reaction temperature and methanol-to-oil ratio), to design experiments carried out for the production of biodiesel using used cooking oil and methanol in the presence of alkaline catalyst. After carrying out the experiments using the design parameters generated, the results were analysed, and a model equation was developed for the system. Furthermore, the model equation was used to optimize the process using Excel Solver to obtain a temperature, a methanol-to-oil ratio and a yield of 63.45 °C, 3 and 59.32 as the optimum values, respectively. The optimum parameters estimated were validated experimentally and with the Aspen HYSYS model of the process that was also developed. The results obtained using the design factors showed that the factors considered were having effects on the yield of biodiesel. Also, the results of the experimental validation carried out with the optimum parameters obtained with the aid of Excel Solver were found to compare very well with those obtained from the simulation of the developed Aspen HYSYS model of the biodiesel production because the errors were estimated to be less than 5%. Therefore, the developed Aspen HYSYS model of biodiesel production of this work was able to represent the process very well and can be used for further studies on the process.