Deactivation Studies of the CrOx/Al2O3 Dehydrogenation Catalysts under Cyclic Redox Conditions
In this work, the deactivation of a CrOx/Al2O3 dehydrogenation catalyst in an industrial reactor has been systematically studied under cyclic dehydrogenation–regeneration conditions from start up to end of run. The results showed that the CrOx/Al2O3 catalyst deactivation occurred through three major...
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Veröffentlicht in: | Industrial & engineering chemistry research 2017-07, Vol.56 (28), p.7937-7947 |
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Hauptverfasser: | , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
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Zusammenfassung: | In this work, the deactivation of a CrOx/Al2O3 dehydrogenation catalyst in an industrial reactor has been systematically studied under cyclic dehydrogenation–regeneration conditions from start up to end of run. The results showed that the CrOx/Al2O3 catalyst deactivation occurred through three major processes. The first process is related to the complex transformation of surface chromium species, the second process refers to the phase transformation and/or sintering of support alumina, and the third process is the interfacial CrOx/Al2O3 transformation into the solid solution of α-(Al, Cr)2O3. In addition, the reduction of the chromium oxide surface area and the migration of Cr3+ into the alumina support resulted in the increase of the surface Cr6+/Cr3+ ratio at the end of the run which increased the specific catalyst acidity and reduced the catalyst selectivity. The main causes of irreversible deactivation of the CrOx/Al2O3 catalyst are the decrease of chromium oxide surface area, the formation of α-(Al, Cr)2O3 in the support, and the increase of surface Cr6+/Cr3+ ratio. |
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ISSN: | 0888-5885 1520-5045 |
DOI: | 10.1021/acs.iecr.7b01638 |