Effect of steam on regeneration of Pt-Sn-K-La / γ-Al_2O_3 catalyst for isobutane dehydrogenation

The deactivated Pt-Sn-K-La / γ-Al2O3 catalyst for isobutane dehydrogenation was regenerated by gasifying deposited coke inO2-N2 andO2-N2-steam atmospheres and the obtained products were denoted as sample 1 and sample 2,respectively. The physicochemical properties of the samples were characterized by X-ray fluorescence spectroscopy,NH3-temperature programmed desorption,H2-temperature programmed reduction and so on,and their activity was evaluated in a microreactor.The results showed that the steam effectively reduced the temperature rise of catalyst bed. After the regeneration,the content of chlorine in catalyst decreased. Moreover,the regenerated catalysts also showed a decrease in both Pt dispersion and catalytic acidity. After reacting for 15 h,the isobutane conversion of sample 2 dropped from 51. 8% to43. 6%,slightly less than that of fresh one,whereas its isobutene selectivity was higher than that of the latter.