Catalytic pyrolysis of oily sludge over ZSM-5 zeolite was carried out in a U type fixed-bed tubular reactor. Gas chromatography-mass spectrometry and gas chromatography were employed to investigate the properties of the pyrolysis oil and gas product

respectively. When pyrolysis was conducted without ZSM-5

the main components in the oil product were alkanes and alkenes

and the gas product was composed of short-chain hydrocarbons with little H2. The addition of ZSM-5 significantly increased the aromatics yield (88.4%) in the oil product. Meanwhile

the content of H2 and short-chain hydrocarbons increased as well. The effects of temperature on the catalytic effects of ZSM-5 were studied under 400-550℃. The results showed that 65.6% of oil can be recovered at 500℃ and the aromatics yield reached up to 90.9%. Moreover

the contents of resins and asphaltenes in the oil products were relatively low at this temperature. It can be deduced that the optimum catalytic temperature with ZSM-5 in this study was 500℃. The coke deposited on the catalyst was detected by thermogravimetric and X-ray photoelectron spectroscopy analysis. It was found that the main type of coke was polyaromatics coke due to the polycondensation reaction over ZSM-5.