Fuel quality assessment of ethyl esters produced from vegetable oils and their blends with petroleum diesel.

Abstract

Ethanolysis of four different vegetable oils (sunflower, soybean, cotton seed, and used frying oil) was studied using sodium ethoxide as a catalyst. The ester preparation involved a two-step transesterification reaction, followed by purification. The effects of the mass ratio of catalyst to oil, the molar ratio of ethanol to oil, and the reaction temperature were studied on conversion of sunflower oil to optimize the reaction conditions in both stages. The rest of the vegetable oils were converted to ethyl esters under optimum reaction parameters. Ethyl esters of four different types of vegetable oils were blended with the diesel fuel at 2 %, 5 %, 10 %, and 20 %, on a volume basis. The experimental results showed that the densities and viscosities of the blends increased with the increase of biodiesel concentration in the fuel blend. Cold flow properties were negatively affected as ethyl ester content was increasing. Distillation characteristics and cetane indexes were not significantly altered. These results are promising, and ethyl esters can be seen as a viable fully renewable alternative to petroleum diesel.