Taguchi design approach for extraction of methyl ester from waste cooking oil using synthesized CaO as heterogeneous catalyst: Response surface methodology optimization

The ongoing requirements for fuel in meeting the ever-growing demand in commercial sector have pushed researchers in finding and optimizing the production of biofuels from cheap sources, enabling for a sustainable production. The present study aims at bridging the gap in optimizing the process parameters which are required for converting cheap waste cooking oil (WCO) into methyl esters, using cost effective source of heterogeneous catalyst (Egg shells). Characterization of synthesized calcium oxide (CaO) and the methyl esters were performed. Catalyst calcinations temperature (C-Temp), catalyst calcinations time (C-Time), catalyst loading (C-L), alcohol to oil ratio (A(O)), reaction temperature (R-Temp) and reaction time (R-Time) were being analyzed in a 3-level-6-factor array using an L27 Taguchi orthogonal array (OA). Response surface methodology (RSM) optimization and analysis of variance (ANOVA) test are carried out for determining the most significant parameter. Amongst the entire variable, the transesterification reaction temperatures have a contribution of 30.14%, followed by calcinations temperature with 29.70%. A confirmation test is conducted using the optimal values from both RSM and ANOVA and a yield of 96.6 +/- 0.05% and 96.3 +/- 0.10% respectively is obtained which is more than the predicted value of 96.08% and at par with studies of researchers work. Thus, at same OA design, RSM and ANOVA can be equally applied for optimization.