Experimental study of castor biodiesel ternary blends with ethanol, butanol, diethyl ether and dibutyl ether in a diesel engine.

Energy consumption is growing with each passing day. With the declining oil resources and environmental concerns for the power and transport sector, a search for better alternative is desired. Here, biofuels are one potential source in which castor bean plant, being a non-edible crop, has advantage of facile cultivation in Pakistan. However, castor oil biodiesel suffers from poor performance due to its high viscosity. To overcome this challenge, few researchers tested oxygenated additive-based ternary blends especially with castor biodiesel. Moreover, there is no comparative analysis on performance and emissions of these ternary blends among themselves in a single engine. Hence, we investigated, the effect of castor biodiesel–diesel blend with different oxygenated additives in detail. Ethanol, butanol, diethyl ether and dibutyl ether were used as additives. It was observed that the brake thermal efficiency (BTE) for all blends was lower up to 3.3 kW brake power. Upon increasing to 4.24 kW, the four blends showed higher BTE of up to 30% for the first time by addition of 5% diethyl ether. We also report a significant reduction of NOx (minimum value of 550 ppm) and HC emissions (minimum value of 19.5 ppm) for all ternary blends. The key highlights revealed diethyl ether blend with B20 significantly decreased brake-specific energy consumption by 8%, increased brake thermal efficiency by 8.76%, decreased brake-specific fuel consumption by 2.6% and decreased CO and HC emissions by 15.7% and 47.3%, respectively, at highest applied load against brake power of 4.24 kW when compared with diesel. Furthermore, it also showed significant reduction in NOx and CO2 emissions at all loads. Our study would be useful for finding economic as well as environmentally friendly renewable energy sources to substitute diesel with castor-based B20 blends. [ABSTRACT FROM AUTHOR]