Optimization of coco-biodiesel production through conventional and micro-wave heating and phase equilibria analysis of the transesterified coconut oil using the unifac-lle model

Biodiesel as an alternative source of fuel energy has drawn the attention of the scientific community as well as governments. Conventional methods of transesterification have almost become stable for numerous edible and non-edible oils through the use of conventional sources of heat. Other transesterification processes can be accomplished using microwave radiation. Using microwaves, transesterification completes at a time noticeably shorter thus reducing unwanted by-products. This study used refined coconut oil as feedstock, and considered the effects of time, temperature, catalyst and alcohol ratio on conversion. Heat sources were a thermostatic water bath for conventional transesterification and a modified kitchen microwave for microwave irradiation. Conversion was compared for both production processes. The highest conversion apparent for the former heat source within 30minutes reaction time using 12:1 ethanol to ratio, and potassium hydroxide as catalyst was at 96.7%. On the other hand 99% conversion was observed using microwave heat with an ethanol to oil ratio of 12:1, using sodium hydroxide as catalyst and 5 minutes reaction time. Phase equilibrium analysis was also conducted for the transesterified product. Process difficulties have arisen from the well-known production methods. One of the most prominent is the complexity in optimizing operating parameters and conditions without available thermodynamic data particularly phase equilibrium data. For phase behavior analysis, the UNIFAC-LLE thermodynamic model was used for this study to predict component behavior at 50°C and 70°C varying the alcohol concentration. Ternary phase diagrams of coco-biodiesel-ethanol-glycerol were derived to determine the correlation between the UNIFAC-LLE predicted results and the experimental data. The model showed did not give an accurate prediction for the phase behavior of the sample. It however illustrated a trend that is considerably the same as the experiment data