Biodiesel production from Pongamia pinnata – A versatile resource for bioenergy production in Indian scenario for carbon neutrality

In this study the versatility of Pongamia pinnata fruit as a sustainable resource for biodiesel production has been highlighted as a reliable substitute to the diminishing and polluting diesel fuel. Botanical features of Pongamia have been studied and its relevance in Indian context as an excellent non-edible resource for biodiesel production with an oil potential of 55000-135000 tonnes per annum has been analysed. Base-catalysed (single stage) transesterification process is adopted for the production of biodiesel and the parameters affecting the process have been outlined. The physicochemical properties of the produced biodiesel such as acid value (0.436 mg KOH/g), density (872 kg/m³), kinematic viscosity (5.3 cSt), calorific value (38.2 MJ/kg) were experimentally evaluated. Gas chromatography analysis was conducted to identify the fatty acid methyl ester composition of the biodiesel produced. Properties such as cetane number, saponification number, iodine value, cloud point and pour point have been empirically evaluated. All the investigated properties successfully complied with the ASTM standards indicating the satisfactory quality of biodiesel and the aptness of Pongamia oil as a feedstock. Further, the carbon neutrality aspects of Pongamia as a bioenergy source are highlighted.