FAME production from residual materials: optimization of the process by Box-Behnken model

In the worldwide more than 95% of biodiesel production feedstocks come from edible oils. The waste cooking oils (WCO) are an alternative feedstock for biodiesel production; its usage reduces significantly the cost of biodiesel production and has environmental benefits, e.g., a waste recovery instead of its elimination. This work aimed to optimize the process to produce fatty acid methyl esters (FAME) using the response surface methodology and a Box-Behnken experimental design from mixtures of refined palm oil (RPO) with WCO using a residual solid material as catalyst (biomass fly ashes). The influence on FAME yield of four operational variables (catalyst loading, methanol/oil molar ratio, RPO/WCO ratio and reaction temperature) was studied. The higher FAME yield achieved using the RMS method was 77.06% for: 14.63 wt% of catalyst loading, 5.42/1of methanol/oil molar ratio, 14.81 wt% of RPO in the oil mixture and 55 °C for the reaction temperature.