Experimental study on moringa oleifera biodiesel fuelled ci engine with fuel modifications and injection strategies

Abstract

Global energy consumption has been increasing daily due to industrialization and population growth. The present energy demand is being fulfilled by fossil fuel based petroleum diesel fuel. Concern over the depletion of fossil fuel, environmental pollution, global warming, and rapid increase in petroleum diesel prices have stimulated research to search for alternative renewable sources. Biodiesel is a promising substitute fuel for diesel engines due to its fuel properties, which are similar to conventional diesel. This work deals with biodiesel production from low feedstock source like moringa oleifera oil. Also, this work evaluates diesel engine performance, combustion and emission characteristics fuelled by conventional diesel and biodiesel. First phase of the work deals with extraction of biodiesel from moringa oleifera oil. Biodiesel process parameters were optimized to achieve a maximum biodiesel yield using D-optimal design. Process parameters are reaction time, reaction temperature, molar ratio of oil and alcohol, catalyst concentration and stirrer speed. Biodiesel is synthesized using sodium methoxide as a catalyst. Experimental results revealed that a maximum biodiesel yield of 96.71 % is acquired with following reaction conditions such as molar ratio 6:1, reaction temperature 60°C, catalyst 1.8 wt%, the reaction time 120 min and a stirrer speed 600 rpm. Second phase of the work deals with the effect of moringa oleifera biodiesel and biodiesel-diesel-carbon black water emulsion blends on diesel engine characteristics. The engine test is carried out at no load, 25%, 50%, 75% and full load conditions and engine running at 1500 rpm. Results reveal that B20-D75-CBWE5 blend acquires the lowest BSFC of 0.381 kg/kWh compared to other tested fuel blends and B100 acquires highest BSFC of 0.425 kg/kWh. Higher BTE of 25.9% is acquired for B20-D75-CBWE5 blend. At full load, the least CO emission of 0.30% vol. is acquired for B100. Maximum NO emission of 965 ppm is acquired for B20-D75-CBWE5. B100 blend has the lowest NO and unburnt hydrocarbon emission of 746 ppm and 38 ppm respectively. Least smoke opacity of 34% is acquired in B100 at 100% load. B20-D75-CBWE5 has a maximum In-cylinder pressure and heat release rate of 37.4 bar and 67 kJ/m3 ºCA. Biodiesel-diesel-carbon black water emulsions blends increase the diesel engine characteristics and lower the engine exhaust emissions compared to conventional diesel. newline