Transesterification of waste frying oil for synthesizing biodiesel by KOH supported on coconut shell activated carbon in packed bed reactor

Heterogeneous catalysis of transesterification using potassium hydroxide supported on coconut shell activated carbon (KOH/AC) catalyst was used to produce biodiesel from waste frying oil (WFO) and methanol. The effects of reaction temperature, methanol to oil molar ratio, catalyst bed height, reaction time, and reusability of catalyst on the conversion to fatty acid methyl ester in a packed bed reactor were studied. The results showed that increasing reaction temperature, methanol/oil molar ratio, catalyst bed height, and reaction time can enhance the conversion of WFO. The optimum conditions were a reaction temperature of 60 degrees C, methanol/oil molar ratio 25:1, catalyst bed height 250 mm, and reaction time 2 h which yielded 86.3% of the conversion. KOH/AC could be used repeatedly for 4 times without activity loss and no activation treatment was required. The fuel properties of biodiesel were determined.