Single and combined effects of process parameters on biodiesel produced from blends of palm kernel shell and cocoa pods oils with titanium oxide as catalyst

Effects of process parameters on biodiesel produced from blend of palm kernel shell (PKS) and cocoa pods (CPO) oils, is investigated. These bio-oils were transesterified with methanol in the presence of titanium oxide as catalyst. The study shows a significant effect of the process parameters on the properties of biodiesel and its yield. The process parameters - catalyst concentration, reaction time, reaction temperature, methanol/sample ratio and agitation speed - were studied individually and in matrix form to establish synergistic interactions. Catalyst concentration of 5wt%, methanol/sample ratio of 6:1, agitation speed of 250rpm, reaction time of 90 minutes and temperature at 60oC was the optimal process conditions that gave the maximum yield of 76.05%. Other set of conditions that resulted the lowest biodiesel yield of 34.22% were catalyst concentration of 1.5%, methanol/sample ratio of 4:1, agitation speed of 150rpm, reaction time of 30 minutes and temperature of 40oC. The physiochemical properties of the yield investigated to ascertain their adherence with the American Society for Testing and Materials (ASTM) and European Nation (EN) standards for biodiesel production revealed that the developed biodiesel properties conformed with the recommended standards. Response Surface Methodology (RSM), which identified the various numerical and discrete design points was employed to achieve the optimum process parameters for the production of biodiesel using titanium oxide as catalyst. ANOVA statistics was also used to predict the biodiesel yield and to understand the combined effects of the process parameters. For single effect, result shows that amongst the five (5) variables studied, the methanol/oil (B) had the largest effect on the biodiesel yield as it took the highest F-value (11.26) while the least was the reaction time (D) with the lowest F-value of 0.2225. For the combined effect, methanol and temperature (BC) had the highest effect on the biodiesel yield as it took the highest F-value (12.01) while the least was catalyst concentration and time (AD) with the lowest F-value (0.0016).