Study of Thermal Stability and Characterization of the Biodiesel from Waste Frying Oil

Biodiesel or methyl esters (ME), originated from Waste Frying oil (WFO), was prepared by aiming at the maximum ME conversion. The biodiesel was synthesized via transesterification using a homogeneous catalyst. A statistical experimental design, response surface methodology (RSM) was implemented to optimize the experimental conditions and to understand the interactions among the process variables. The optimum conditions inferred from the RSM were temperature, 58.30 °C; catalyst loading, 0.51 wt%; and ratio molar alcohol/oil, 7.3:1. At this optimum condition maximum yield of methyl esters was found to be 96.33 wt%. Esters conversion were confirmed and supported by nuclear magnetic resonance spectral technique (¹H) and Fourier transform infrared spectroscopy (FTIR). Physico-chemical properties of WFO and their biodiesel were determined by standard methods and compared. The thermo-analytical technique, such as thermogravimetric analysis (TGA), was applied to the thermal stability analysis of petroleum fuels, biodiesel, and WFO. Physic-chemical characteristics of biodiesel were evaluated and the results suggested that the qualities of biodiesel were feasible.