Optimization and transesterification of sterculia oil: Assessment of engine performance, emission and combustion analysis

Abstract

Biodiesel is considered as an alternative for petroleum fuels. Hence, identifying efficient biomass for biodiesel production is necessary to meet the demand. This study reports the optimum conditions of Sterculia foetida oil for biodiesel production and its engine performance, emission and combustion analysis. Gas Chromatography-Mass Spectrometry revealed the dominance of fatty acids in the order of sterculic acid (32%) > palmitic acid (15.88%) > oleic (10%) > linolenic (9.95%) > malvalic acid (9%) respectively. Oil extracted from the seeds of Sterculia foetida were purified by the degumming process to remove the unwanted impurities present in the oil. Box-Benhken design was used for optimizing transesterification process. A Maximum biodiesel yield of 90.2% was obtained at a temperature of 55 °C, catalyst concentration 1.5%, Oil to methanol ratio 1:12, agitation speed 900 rpm. ANN model was also utilized for the prediction of biodiesel yield using feed-forward backpropagation exhibited significant correlation (R2 - 0.9) with experimental results. Biodiesel blends and their properties were also analysed. Carbon monoxide and hydrocarbon emission were found to be low with the observation of increased nitrogen oxide emission. D90STB10 and D80STB20 was showing better performance and also lesser emission ompared to the conventional fuel.Combustion analysis of Sterculia foetida biodiesel (STB) and biodiesel blends (D90STB10, D80STB20, D70STB30, D60STB40 and STB100) for the various load at constant speed were analysed. Cylinder gas pressure, cumulative heat release rate, heat release rate, mass fraction burnt and mean gas temperature were discussed in the current paper.