Abstract: XRD, N2 adsorption, NH3-TPD and TEM were used to characterize the surface acidity, pore structure, phase changing of the deactivated Pt/H-ZSM-22 catalysts in order to find out the causes of catalyst deactivation. The coke contents on the catalysts run for 3 000 h and 7 600 h were 3.20 % and 7.84%, respectively, which indicated that the coke deposition was the main cause of the decrease of catalyst pore volume and specific surface area, and that would lead to catalyst deactivation. The existence of sulfur- and nitrogen-containing compounds in the feed would also cause the deactivation of catalyst. Using conventional regeneration to burn off the coke deposited on the catalyst could effectively recover the catalyst properties, such as the recovery rate of pore volume and specific surface area was more than 96%.

Key words: platinum, molecular sieve catalyst, deactivation, regeneration