The role of antioxidants in improving biodiesel's oxidative stability, poor cold flow properties, and the effects of the duo on engine performance: A review

Global competitiveness thrives on meeting energy demand, and the need to counter the effects of environmental threads dispatched by the combustion of fossil fuels became the driving forces that upended the renewed commitment and growing interest in renewables. Alternatively, green energy provides a twofold solution to energy and environmental crisis in a sustainable, economically viable, and eco-friendly manner. However, energy from biomass, especially biodiesel is considered an attractive substitute for mineral diesel, with the proficiency of meeting future energy demand. Inevitably, biodiesel exhibits poor cold flow properties leading to plugging and gumming of filters, whereas oxidation stability results in sediments and gum formation. These effects present a legitimate concern to producers and the automotive sector. Many reviews on the use of antioxidants to improve biodiesel's cold flow and oxidative stability flooded the literature independently. Yet, a review encompassing the factors inducing biodiesel's poor cold flow, oxidation stability, their effects on engine performance, and the inhibitory role of antioxidants appears vacant. Hence, this paper put together the above-stated aspects, with the first part discussing the factors initializing and accelerating oxidation, the mechanism of oxidation, and biodiesel cold flow were subsequently discussed. Next, the inhibitory functions of antioxidants on biodiesel's oxidation stability and poor cold flow were also explained. Finally, this review reflects on the research trends and sustainability prospects of using antioxidants for improving biodiesel's poor flow and oxidative stability without hindrance to the engine system.

Experimental assessment of non-edible candlenut biodiesel and its blend characteristics as diesel engine fuel

Exploring new renewable energy sources as a substitute of petroleum reserves is necessary due to fulfilling the oncoming energy needs for industry and transportation systems. In this quest, a lot of research is going on to expose different kinds of new biodiesel sources. The non-edible oil from candlenut possesses the potential as a feedstock for biodiesel production. The present study aims to produce biodiesel from crude candlenut oil by using two-step transesterification process, and 10%, 20%, and 30% of biodiesel were mixed with diesel fuel as test blends for engine testing. Fourier transform infrared (FTIR) and gas chromatography (GC) were performed and analyzed to characterize the biodiesel. Also, the fuel properties of biodiesel and its blends were measured and compared with the specified standards. The thermal stability of the fuel blends was measured by thermogravimetric analysis (TGA) and differential scan calorimetry (DSC) analysis. Engine characteristics were measured in a Yanmar TF120M single cylinder direct injection (DI) diesel engine. Biodiesel produced from candlenut oil contained 15% free fatty acid (FFA), and two-step esterification and transesterification were used. FTIR and GC remarked the biodiesels' existing functional groups and fatty acid methyl ester (FAME) composition. The thermal analysis of the biodiesel blends certified about the blends' stability regarding thermal degradation, melting and crystallization temperature, oxidative temperature, and storage stability. The brake power (BP), brake specific fuel consumption (BSFC), and brake thermal efficiency (BTE) of the biodiesel blends decreased slightly with an increasing pattern of nitric oxide (NO) emission. However, the hydrocarbon (HC) and carbon monoxides (CO) of biodiesel blends were found decreased.

Production, characterization, engine performance and emission characteristics of Croton megalocarpus and Ceiba pentandra complementary blends in a single-cylinder diesel engine

Potentiality and sustainability of two biodiesel feedstocks namelyCroton megalocarpusandCeiba pentandrahave been investigated. 20% (v/v) optimum combined blending of this two sources can substitute the fossil diesel.