Catalytic conversion of used vegetable oil to liquid fuels over HZSM-5 and sulfated zirconia

Abstract

The emphasis of this study was on catalytic cracking of used vegetable oil which classified as a waste which has potential for conversion into liquid fuels where performed in a batch microreactor at temperature of 400-430 ํC, initial pressure of hydrogen gas at 10-30 bars, and reaction time of 45-90 minutes. The catalysts such as HZSM-5, sulfated zirconia and hybrid of HZSM-5 with sulfated zirconia were used to determine on the conversion and yield of gasoline fraction. The major products obtained were liquid product, hydrocarbon gases and small amount of solid. Liquid products were analyzed by simulated distillation gas chromatograph and the product distribution was obtained. Hybrid catalyst obtained with physical mixing of HZSM-5 and sulfated zirconia at ratio of 0.3:0.7 showed the highest yield of gasoline with of 26.57 wt% at the temperature of 430 ํC, hydrogen pressure at 10 bars, and reaction time of 90 minutes. Moreover, kerosene 10.65 wt%, light gas oil 23.02 wt%, gas oil 6.05 wt% and long residue 12.88 wt% whereas the light gaseous by product of 20.20 wt% and solids of 0.63 wt% were obtained. Hence, the addition of small amount of HZSM-5 to sulfated zirconia was a route to modify performance of catalytic cracking to increased gasoline fraction. The kinetic model of catalytic cracking used vegetable oil to liquid fuels over hybrid catalyst as the second order and shown the activation energy of 116.072 kJ mol[superscript -1] and pre-exponential factor (A) = 2.67 x 10[superscript 5] s[superscript -1]