Thesis (M.Sc.)--Chulalongkorn University, 2013

The aim of this research was to study the pyrolysis of used vegetable oil over spent FCC catalyst in a batch reactor of 70 ml. The process was performed at 380-450 ˚C, reaction time 30-60 min, initial hydrogen pressure 1-5 bars, containing 1-5 wt% of spent FCC catalysts. The two level factorial experimental designs were performed to investigate the effect of variables on oil yield. It found that temperature of reaction, the amount of catalyst, reaction time, initial pressure, catalyst and pressure of reaction interaction and pressure and time of reaction interaction were significant affect to oil yield product. Liquid products were analyzed by simulated distillation gas chromatography. The optimum condition was found that temperature of 400 ˚C, reaction time 60 min and initial hydrogen pressure 1 bars by using 5 wt% of spent FCC catalyst. The oil yield product was 73.21 wt%, 20.65 wt% of gaseous product and 6.14 wt% of solid and oil yield product was consisted of 19.88 wt% of naphtha, 10.21 wt% of kerosene, 31.02 wt% of diesel and 12.10 wt% of long residue. The analysis of functional groups with a Fourier Transform Infrared Spectrophotometer found a functional group of long chain aromatic in large amounts in main structure similar to the functional groups of gasoline petroleum fuel.