Correlation between CO ₂ Emission and Apparent Activation Energy of Renewable Fuels and their Blends

Biofuels have become an alternative to replace the fossil diesel in diesel engine. In this study, CO2 emissions and activation energies(Ea) have been determined for two renewable biofuels (farnesane and biodiesel), a fossil diesel and their blends. CO2 emissions were determined in an European Stationary Cycle (ESC) OM 926 LA Euro 5 diesel engine. Activation energies were determined by means of a mathematical model (Model Free kinetics) using experimental data from Thermogravimetric analysis. The result showed that the lowest values of both CO2 emissions and activation energies were obtained for farnesane/diesel blends when compared with biodiesel/diesel blends. CO2 emissions are described in this study as normalized values considering 100% of CO2 for pure fossil diesel and reduction of 7.5% and 1.9% were obtained for farnesane/diesel and biodiesel/diesel blends respectively. When farnesane was added to the diesel, a CO2 reduction of 7.5% was observed. The lowest values of Ea were also obtained for farnesane/diesel blends. According to our finds, lower values of Ea are correlated with the reduction of the CO2 emissions. The direct correlation between activation energy and CO2 emission can be understood in terms of molecular structure and ease of ignition