Metals modification of the paraffin dehydrogenation catalyst regenerated by coke combustion

• Commercial paraffin dehydrogenation catalyst deactivates rapidly, longer life-time required.
• Catalyst regeneration via coke burn off recovers catalytic activity only partially.
• Metals modification improves Pt dispersion and enhances Pt-SnOx-Al2O3 site fractions.
• Metals modification results in longer catalyst life-time in an industrial site test.
• Strategy developed for reuse of long chain paraffin dehydrogenation catalyst.

The industrially deactivated Pt0.5-Sn1.5-K0.5-Mg1/γ-Al2O3 catalyst for dehydrogenation of long chain paraffins (n-C10°–C13°) was regenerated by coke burn off and metals (Pt, Sn and K) modification. The catalysts were characterized by TG, BET, CO-chemisorption, H2-TPR, XRD and mechanical crushing strength test. Paraffin dehydrogenation was performed on a bench reactor at the industrial site. Results showed that temperature increase during coke combustion can be effectively controlled with O2 content lower than 1%. The combustion temperature should be higher than 500 °C to burn all the coke and lower than 550 °C to avoid Pt sintering. Under optimal conditions, coke combustion results only in 92% recovery of catalyst activity. Subsequent metals modification with additional 0.01 wt.% Pt addition can recover catalytic performance completely, paraffin conversion and olefin selectivity to the levels of fresh catalyst. The modified catalyst has longer life-time of 77 days compared to fresh catalyst of 69 days. Results are explained in terms of the characteristics of the catalysts.

Figure optionsDownload high-quality image (242 K)Download as PowerPoint slide