Search Results

In this study, the transesterification process of 4 different vegetable oils (sunflower, rapeseed, olive oil and used frying oil) took place utilizing ethanol, in order to characterize the ethyl esters and their blends with diesel fuel obtained as fuels for internal combustion engines. All ethyl esters were synthesized using calcium ethoxide as a heterogeneous solid base 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. The optimal conditions for first stage transesterification were an ethanol/oil molar ratio of 12:1, catalyst amount (3.5%), and 80 °C temperature, whereas the maximum yield of ethyl esters reached 80.5%.

The present paper is an effort to evaluate ethanol in diesel fuel and its main alternatives. The fuels used were an ultra low sulfur diesel fuel containing 15% by volume gas-to-liquid (GTL), JP-5 and JP-8 fuels produced in Greece and biodiesel produced from animal fats. The fuels were tested for compliance to the respective specifications at the Fuels Laboratory of the National Technical University of Athens (NTUA). The test fuel matrix consisted of blends of 5-15 % by volume ethanol with diesel, JP-5, JP-8 and with mixtures of the above with 5% by volume biodiesel. The test fuels were used in a stationary single-cylinder diesel engine with indirect injection, in order to evaluate their performance and emissions under various loads.