The Influence of Chemical Structure of Fatty Acid Alkyl Ester on Properties, Combustion Characteristics, and Emissions: A Review

Alarming situation of world fossil fuel and environment degradation has been stimulating the researchers and engineers to find new sources of fuel, which must be renewable, economically available and environment friendly. In this regard biodiesel has one of the most substantial alternative renewable fuels for diesel engine. Biodiesel has made from different feedstock depending on the availability. This study is related to effect of fatty acid composition on combustion characteristics, properties and emission of biodiesel. The main advantage of biodiesel is that it potentially reduces the key pollutants like CO, HC, PM and smoke opacity but on other hand it has increased NOx and BSFC. The results of the study show that biodiesel with high saturate fatty acid has shorter delay period, low NOx, high CN, high CV and higher oxidation stability, which has favourable aspect but on other hand it has high viscosity and high cold flow properties which is unfavourable. But biodiesel with high unsaturated fatty acid has low viscosity, low cold flow properties, longer delay, high NOx, low CN, low CV and lower oxidation stability. Keywordbiodiesel; chemical structure; fatty acid; properties; emission