Production of biodiesel from Sterculia foetida and its process optimization

The diminishing supply of fossil fuels reserves and the environmental concerns have made renewable energy an alternative energy source for the future. Sterculia foetida is one of the possible non-edible feedstocks for biodiesel production. This paper explores and examines the potential biodiesel production from S. foetida. Besides, this study also aimed to optimize the biodiesel production parameters by using design of experiment (DOE). The parameters involved in the optimization process were the amount of catalyst, reaction temperature, agitation speed and reaction time. Crude S. foetida oil has high acid value which is 5.11 mg KOH/g. Thus, two stage acid catalyst esterification and base transesterification methods are used to produce biodiesel from S. foetida. The optimum biodiesel conversion efficiency obtained was 93.55% by 1 vol.% of sulfuric acid with 12:1 of methanol to oil ratio at 60 °C and 1200 rpm agitation rate for 3 h. On the other hand, the transesterification process condition is 1 wt.% sodium hydroxide catalyst with 12:1 methanol to oil at 55 °C for 2.5 h. The high viscosity (63.90 mm2/s) of crude S. foetida oil was reduced to 3.96 mm2/s after the transesterification process. Moreover, the properties of the produced S. foetida methyl esters and all the measured properties are within the limits of ASTM D 6751 and EN 14214 specifications. Therefore, S. foetida oil is one of the non-edible feedstocks for biodiesel production