Biodiesel performance and emission study using nano sized particles as additive: A review

Nowadays the world is largely dependent on conventional energy sources which are non-renewable and its demand is increasing day by day. The emission due to utilization of these energy resources causes air pollution and human disease. So researchers are focusing their attention on biodiesel as an alternative to diesel. Biodiesel while being renewable, environment friendly, has poor performance and higher NOx emission. To eliminate these problems up to some extent, blending with diesel can be done but increasing blending percentage again causes the same problem. To eliminate these demerits of biodiesel researchers are using nano sized particles as additives to biodiesel. A large number of nanoparticles are used as additives and resulted in improved performance and emissions, viz. increased “brake thermal efficiency”, reduced “brake specific fuel consumption” (bsfc), lower release of Hydrocarbon (HC) and Carbon monoxide (CO) etc. Apart from poor performance, higher NOx release is the main concern with the use of biodiesel. Some nanoparticles reduce NOx emission while use of some other nanoparticles result in increased NOx emission. NOx emission varies with the concentration of nano particle as well. This paper reviews the research work in which nanoparticles such as CeO2, TiO2, GO, CaO, Al2O3, Bi2O3, SiO2, ZnO, NiO, Ag-O, CNT, MWCNT, nano water emulsion as well as combination of these nano sized particles have been used as additives to biodiesel or biodiesel blends.