Microemulsification-based hybrid oxygenated biofuel for CI engine locomotives: with special reference to...

In recent years, rising environmental concerns and the detrimental impact of emissions from the growing number of locomotives have prompted scientists to investigate alternative fuels derived from renewable lipids, such as microemulsion-based hybrid biofuels (MHBFs). Petro crops and lignocellulosic biomass are the common agricultural and forest feedstocks for biofuel production. Biofuel can be characterized in terms of its volatility range, physicochemical properties, composition, combustion, and emission characteristics. This paper elaborated on the petrodiesel-like oxygenated biofuel obtained from different feedstocks, their preparation, and performance analysis viz. the microemulsion-based hybrid oxygenated biofuel. In this paper, preparation steps such as the microemulsion type, concentration ratio, microemulsion component, surfactant, and phase separation of microemulsion as well as the basic precautions to form a stable microemulsion have been addressed. The analysis of performance, emissions, and overall efficiency of especially locomotive compression ignition (CI) engines has been extensively studied across various combustion engine types. MHBF is a multi-component biofuel system, consisting of ethanol, butanol, vegetable oil, and many other combustible liquid and fuel fractions as available in the literature. The engine performance metrics, specifically brake thermal efficiency and brake-specific fuel consumption, have been evaluated and show that these values are comparable between biodiesel blends, petrodiesel, and pure petrodiesel. Various researchers have reported that emissions, particularly CO and NO_x, are significantly lower when using MHBF compared to biodiesel and petrodiesel. The review suggests that MHBF has the potential to eventually replace other renewable liquid fuel formulations for CI engines due to its simple preparation process.