Coke burning behavior of deactivated Pt-Sn/AlR2ROR3R dehydrogenation catalyst

The coke burning behavior of deactivated Pt-Sn/AlR2ROR3R iso-butane dehydrogenation catalyst was studied. During the dehydrogenation, catalytic activity decreases due to the pore blockage from coke deposition. The coked catalyst was prepared from dehydrogenation of isobutane at 575 °C for 100 h on stream. Coke burning was performed in a fixed-bed reactor at 480 °C under 1% OR2R in NR2R/OR2R mixture. The carbon oxides concentrations from coke burning was analyzed with an online analyzer and coke burning was continued until the COx concentration was zero. The amount of coke was calculated by numerical integration (using trapezoidal rule). The fresh, coked and de-coked catalysts were characterized by BET, DTG and TGA analyses. Complete coke removal was achieved only above 480 °C under the flow of Airstream. A power law kinetics for coke burning was established for the catalyst. A power of 0.6 was obtained for coke amount with rate constant of 0.0002 hP-1P.

Keywords:

Dehydrogenation catalyst , Coke burning , De-coking kinetics