การผลิตไบโอดีเซลแบบสองขั้นตอนจากไขวัวโดยให้ความร้อนด้วยคลื่นไมโครเวฟแบบกะ

Abstract

Biodiesel production for alternative fuel has become important since diesel price is growing. Biodiesel production from local feedstock is interesting. This study was about laboratory scale, batch biodiesel production from beef tallow with microwave as a heat source. Microwave heating transfer efficiency was found to be 66%. Central Composite Design was used to design experiments, and analyzed with response surface solution to find optimized solution for esterification and transesterification process. In esterification process, beef tallow was reacted with methanol in the molar ratio of 1:3 – 1:15, with sulfuric acid concentrations between 0.5-2.5 wt% as a catalyst. Reaction time was between 10-50 min. The results showed that the maximum condition was at molar ratio 1:12, catalyst concentration of 1.35%, and 30 min for reaction time. In transesterification process, esterified oil was reacted with methanol in the molar ratio of 1:3 – 1:15, with sodium hydroxide concentrations between 0.25-1.25 wt% as a catalyst. Reaction time was between 10-50 min. The results showed that the maximum condition was at molar ratio 1:9, catalyst concentration of 0.62%, and 25 min for reaction time. The biodiesel obtained has 89.9% ester content, 22 ºC cloud point, 16 ºC pour point, 51.6 sec viscosity at 100 ºF and 0.86 for specific gravity respectively. From energy balance, it was shown that overall energy loss for two step biodiesel production from beef tallow was equal to 7,850 kJ/kg (37.46% in washing oil process). Total raw material and energy cost for biodiesel from beef tallow was 40.83 Thai bath/liter.