Production, characterization and utilization of second generation biodiesel blend in diesel engine using water and nanoparticles as additives

The rapid burning of fossil fuels and their noxious impact on the environment impelled researchers to explore the alternative fuels. In recent time, biodiesel gained much attention due to its potential ability to mitigate the harmful pollutants emitted from internal combustion (IC) engines. However, elevated NOx emission from biodiesel fueled engine remains a key challenge in the large scale adoption of biodiesel. To address these challenges, a study was aimed on the production of a second generation biodiesel, its characterization and application of biodiesel-diesel blend in diesel engine using water and CeO2 nanoparticles. A total of four test fuels viz. CeO2 nanoparticles doped water-B20 emulsion fuel (NWB20E), water-B20 emulsion fuel (WB20E), biodiesel-diesel blend (B20) and diesel were used in the present study. These test fuels were checked for physico-chemical properties as per ASTM Standards prior to engine application. Thereafter, these were used in a 10 kW diesel engine to assess its working characteristics under variable loading cycle. Adding CeO2 nanoparticles with WB20E improved in-cylinder peak pressure, while reduced peak pressure rise rate as compared to diesel. Water and surfactants used in WB20E caused faster fuel burning under premixed and controlled burning phases, which further improved with NWB20E, shortening the total fuel burning time as compared to diesel. The brake thermal efficiency of engine improved while brake specific energy consumption reduced for NWB20E over diesel. The fuel energy losses with exhaust gases and unaccounted energy were lesser for water emulsified fuels than diesel. The secondary atomization of water droplets and catalytic activity of nanoparticles in NWB20 caused 19.4-55.6%, 6.5-52.8% and 23.2-41.5% lesser HC, CO and NOx emissions, respectively, over diesel. In summary, biodiesel-diesel blend dispersed with water and CeO2 nanoparticles could be a promising alternative fuel for diesel engine with lower emissions.