Production, combustion and emission impact of bio-mix methyl ester fuel on a stationary light duty diesel engine

Abstract

NOx emissions are the major threat in biodiesel fuelled engines due to fuel bound oxygen and presence of double bonds in their molecular structure. An attempt has been made to reduce the biodiesel NOx emission by varying the saturation level with the help of an approach called “bio-mix”. In this study, bio-mix fuel has been prepared from the waste resources of raw mixture of pig fat and waste cooking oil. Five samples of raw bio-mix oil have been prepared from the different blend ratio of pig fat and waste cooking oil and converted into biomix methyl ester (BMME) samples through transesterification process such as BMME-1, BMME-2, BMME-3, BMME-4 and BMME-5 respectively. All the bio-mix samples have been tested on a single cylinder, light duty stationary diesel engine. Results show that the percentage of saturated fatty acids, cetane number, and calorific values have increased whereas viscosity and iodine values have decreased with an increase in blend ratio. Bio-mix methyl ester fuel shows better combustion, performance compared with waste cooking oil biodiesel (WCOB). Bio-mix methyl esters shows higher in-cylinder pressure and heat release rate which is lower than WCOB at all engine load condition. All the emissions such as NOx, Smoke, CO, and HC have been found lower for BMME compared to WCOB. The non-road diesel engines are also consuming the fossil diesel fuel and hence, this study suggest that bio-mix fuel can be a viable alternative fuel for stationary diesel engines widely used in utility power generation, agriculture and construction equipments.