An Experimental Investigation on Performance, Emission, and Combustion Characteristics of a Diesel Engine Fueled with Methyl Esters of Waste Pork Lard and Diesel Blends

The aim of this research work is to investigate the possibility of using methyl esters from animal fats as an alternative fuel for diesel. Biodiesel is an alternative fuel produced from different kinds of vegetable oils and animal fats. It is an oxygenated, non-toxic, sulfur free, biodegradable, and renewable fuel which can be used in diesel engines without any significant modification. In this research work, waste pork lard methyl ester (WPLME) is obtained from inedible animal tallow, namely, waste pork lard by base-catalyzed transesterification with methanol in the presence of potassium hydroxide (KOH) as catalyst. Properties of pure diesel, pure biodiesel (B100), and its blends of 25%, 50%, and 75% by volume called B25, B50, and B75 are determined. The effects of waste pork lard methyl ester (biodiesel) addition to pure diesel on the performance, emission, and combustion characteristics of naturally aspirated, direct injection, diesel engine have been experimentally investigated at the maximum torque and constant engine speed of 1500 rpm. The experimental test results showed that the addition of WPLME to diesel slightly decreases the brake thermal efficiency of the engine and increases specific fuel consumption when compared to pure diesel. This is due to lower calorific value of WPLME. The brake thermal efficiency is decreased by 6.2% and specific fuel consumption is increased by 23.5% for pure WPLME (B100) when compared to pure diesel at full load of the engine. However for B25 biodiesel blend, the brake thermal efficiency is very close to pure diesel at full load of the engine. The significant improvement in reduction of carbon monoxide (CO), hydrocarbon (HC), oxides of nitrogen (NOx), and smoke emission is found for WPLME and its blends during higher loading conditions. For pure WPLME, CO, HC, NOx, and smoke emission are decreased by 23.1%, 31.5%, 5.15%, and 64%, respectively, when compared to pure diesel at full load of the engine. WPLME exhibited lower heat release rate and shorter ignition delay when compared to pure diesel at full load conditions. On the whole, methyl esters of waste pork lard and its blends can be used as an alternative fuel for diesel in direct injection diesel engine without any significant engine modification.