Process optimization of bio-alkaline catalysed transesterification of flax seed oil methyl ester
Anietie Okon Etim, Paul Musonge, Andrew C. Eloka‐Eboka
Abstract
The use of biological materials and mineral-rich waste resources as potential raw materials for biodiesel production is receiving lots of attention due to their eco-friendly and availability characteristics. In this study, flaxseed oil (FSO) was used for biodiesel production through transesterification reaction catalysed by agro-waste bio-alkaline salt derived from Musa acuminata peels (MAP). The process parameters (catalyst loading, methanol to oil ratio and reaction time) were designed and optimized through response surface methodology (RSM). The waste were washed, dried and calcined to obtain the bio-alkaline solid catalyst, which was further characterised for catalytic properties via FT-IR, XRD and SEM-EDX. The significance of the developed quadratic model was determined by analysis of variance (ANOVA) with the p-value (p < 0.05) and the coefficient of determination (R2 = 0.97) at 95% confident level. Reaction time was found to have the most influential impact among the three parameters considered. At the optimum condition of reaction time of 51.42 min, catalyst loading of 2.70 wt % and methanol to oil molar ratio of 11:1, the experimental yield was 96.50 wt% and the RSM predicted yield was 95.88 wt %. Characterization revealed that potassium is the key elemental composition found in the calcined ash. The synthesized bio-alkaline catalyst was capable of being reused for up to 4 cycles with minimal decrease in biodiesel yields. The physicochemical properties of flaxseed oil methyl ester (FSOME) were also analysed and compared with the international biodiesel standards. Overallresults obtained confirms that it is a viable fossil fuel substitute.