Experimental Investigation of Emissions from Biodiesel

Biodiesel from waste cooking oil offers sustainable alternative to diesel. This paper presents an experimental investigation of combustion of biodiesel derived from waste cooking oil to study the characteristics of biodiesel emissions compared to diesel. The combustion of neat biodiesel and biodiesel blended in different ratios with diesel was investigated using continuous combustion rig. The temperature of combustion gases, emissions of un-burnt HC and NO for different airflow rates were evaluated. Differences in the chemical composition between biodiesel and diesel result in different mechanisms of NO and HC formation. The results provide insight into combustion and emission from biodiesel. It was observed that the combustion gas temperature (CGT), adiabatic flame temperature, unburned hydrocarbon (HC) and carbon monoxide (CO) decrease, while nitrogen oxides (NOx) increases when the proportion of biodiesel is increased in the blend. Combustion of biodiesel blends for 2% excess O2 shows the best compromise between the reduction in unburned HC and the lowest increase in NOx. It can be concluded that biodiesel made from waste cooking oil has potential to use as alternative to diesel fuel in internal combustion engine and has significant environmental benefits compare to diesel.