Transesterificação etílica do óleo de soja residual de fritura utilizando CaO como catalisador

Abstract

With the increase in world energy demand due to population growth and the limited supply of fossil fuels, the development of research on renewable fuels has gained prominence. Among them, the processing of oils and fats through conversion into alkyl esters, popularly known as biodiesel. In this context, the challenge is to achieve high conversion efficiencies using low added value raw materials such as waste oils. In view of this, the objective of this study is to determine the production efficiency of biodiesel via ethylic route from frying residual soybean oil using calcium oxide (CaO) as a heterogeneous catalyst. The transesterification reaction was investigated trying to evaluate, through experimental planning, the effect of some reaction conditions on the conversion of oil to biodiesel. These are: molar ratio alcohol:oil, temperature and reaction time. The reaction product was analyzed by High Performance Liquid Chromatography (HPLC), and the content of triglycerides, diglycerides and monoglycerides was determined. The reaction yield was determined from material balances. A response surface mathematical model capable of predicting yield as a function of operating conditions as well as determining optimal process conditions was proposed and validated. From the model, the 82.8% yield was determined under the following conditions: alcohol: oil molar ratio of 24:1, temperature of 90 ºC and 6 h of reaction time. Based on the results obtained in this work, residual frying oil is envisioned as an attractive, low cost and environmentally friendly feedstock for biodiesel production, as well as the use of ethanol and the catalyst used (CaO).