Microwave irradiation-assisted transesterification of ternary oil mixture of waste cooking oil – Jatropha curcas – Palm oil: Optimization and characterization

Abstract

Palm oil is an incredibly efficient crop, but our dependence on this crop as a primary biodiesel feedstock has threatened food insecurity as it is still perceived as the main source for vegetable oil throughout the world rather than being utilized for fuel. Therefore, the idea of utilizing non-edible food crops and waste vegetable oils could help to overcome the major problems faced by the first generation of biodiesel feedstock. In this study, a ternary oil mixture comprises 50 vol% of waste cooking oil, 15 vol% of Jatropha curcas oil and 35 vol% of palm oil were premixed and developed into biodiesel via esterification and microwave irradiation-assisted transesterification using a modified household microwave in the presence of methanol and potassium hydroxide catalyst. The parameters affecting biodiesel yield were optimized via response surface methodology based on central composite design. The operating parameters were optimized at 0.78 wt% of catalyst concentration, 9.86:1 of methanol/oil molar ratio, 10.5 min of reaction time and 478 rpm of stirring speed with the predicted and experimental yields are at 96.81 and 96.91 %, respectively. The results indicate that the synergistic mixture of ternary oil in WJP biodiesel gives better cold flow properties as well as improves oxidation stability and cetane number.

Keywords

• Biodiesel
• Microwave irradiation method
• Response surface methodology