Passivate vanadium and sodium on FCC catalyst
- Nalco/Exxon Energy Chemicals Ltd., Fawley (United Kingdom)
- Nalco/Exxon Energy Chemicals, Sugarland, TX (United States)
- Refining Process Services, Pittsburgh, PA (United States)
Vanadium has long been recognized as one of the most serious contributors to deactivation of FCC catalysts, and has been the subject of considerable effort in order to reduce its detrimental effects. Several approaches have been implemented to address the problem. Vanadium can be considered both a competitive catalyst and a true catalyst poison. When freshly deposited on the catalyst from cracking and deposition from vanadium porphyrin complexes, vanadium behaves as a competitive catalyst. As such, it competes with the zeolite cracking catalyst to react with the feedstock, promoting dehydrogenation to hydrogen and coke. This behavior is similar to that of nickel, but only about one-fourth to one-half the magnitude. After numerous cycles of oxidation in the regenerator, vanadium is less active as a dehydrogenation catalyst. However, as vanadium oxidizes, it becomes mobile within the system, undergoing both intraparticle as well as interparticle transport. V{sub 2}O{sub 5} is one suspected form of oxidized species. In addition, reaction with steam to form a volatile vanadic acid species, H{sub 3}VO{sub 4}, has also been determined.
- OSTI ID:
- 459078
- Journal Information:
- Fuel Technology amp Management, Journal Name: Fuel Technology amp Management Journal Issue: 1 Vol. 7; ISSN 1087-4003; ISSN FTMAFH
- Country of Publication:
- United States
- Language:
- English
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