Exergy and environmental analyses of natural gas and biogas fuels in an internal combustion engine at part load

Abstract

This paper presents an experimental investigation on a single-cylinder diesel engine fuelled with natural gas and biogas. Biogas was obtained by mixing methane and carbon dioxide (CO2). The analyses were carried out by using the results of experiments on different fuel mixtures at constant engine power. As a result of working at partial load, the energy and exergy efficiencies of the engine were relatively low. When the results were compared by CO2 content of the fuel, it was observed that when the CO2 ratio increased, the exergy efficiency decreased. In addition, an economic analysis was performed based on the equivalent CO2 emission and the average carbon tax in the European Union. Accordingly, natural gas had the highest GWP value and tax amount. As the CO2 content in the fuel increased, the global warming potential (GWP) and the carbon tax to be paid decreased.