Análise experimental energética e exergética da combustão de um grupo gerador usando diesel e mistura biodiesel de soja

Abstract

Energy demand has been for decades in the search of new and alternative sources of fuel for the use in internal combustion engines. Thus it was noticed that the biodiesel of soybean oil has similar properties to the diesel oil as well as it has the advantage of being of vegetal origin, renewable, biodegradable and non-toxic. Therefore, this study brings the energy and exergetic analysis of a generator group operating with different fuels, among them the pure diesel (B0) and the methyl ester mixture transesterified of soybean oil and diesel (B25), both were submitted to different points of load. The tests were performed at steady state and for analyzes it was adopted a control volume. Results were obtained regarding specific fuel consumption, exhaust gas temperature, fuel energy, thermal efficiency, exhaust gas energy and heat transfer losses. Fuel exergies, exergetic efficiency, exhaust gas exergy, destroyed exergy and the exergy of heat transfer losses were also obtained. It was found that the addition of biodiesel in the mixture provided almost the same energy performance as the B0 and the exergetic performance was similar to the energy, thus accompanying the same performances. Therefore, no significant variation of efficiencies was found with the increase of biodiesel (reduction of 0.2 to 3.2% in thermal efficiency and reduction of 2.7 to 5.6% in exergetic efficiency).