Coke and product profiles formed along the catalyst bed during n-heptane reforming. II. Influence of S on Pt/Al{sub 2}O{sub 3} and Pt-Re/Al{sub 2}O{sub 3}

Journal Article · Sat Jun 01 04:00:00 EDT 1996 · Journal of Catalysis

DOI:https://doi.org/10.1006/jcat.1996.0184· OSTI ID:471623

Querini, C A; Fung, S C ^[1]

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1. Exxon Research and Engineering Company, Annandale, NJ (United States)

Studies of coke and product profiles along catalyst beds of Pt/Al{sub 2}O{sub 3} and Pt-Re/Al{sub 2}O{sub 3} during n-heptane reforming have provided insight into catalyst deactivation and reaction mechanisms. The addition of rhenium to a Pt catalyst changes coke and product profiles similar to those observed with an increase in pressure. Sulfur modifies these profiles in the opposite direction of rhenium. It affects the catalyst in a similar manner to a decrease in reactor pressure: a reduction in hydrogenolysis activity, an increase in dehydrogenation and coke-make, and a shift of the maximum in the coke profile toward the bottom of the reactor. Due to a slow stripping of sulfur during reforming reactions, an increasing sulfur concentration along the bed is observed at the end of several-days run. As a consequence, the coke profile does not match exactly with the C5-ring naphthene concentration profile, as was previously found on both unsulfided Pt and Pt-Re catalysts. The observed increase in coke-make and dehydrogenation activity, when sulfur is added to the Pt-Re catalyst, is probably due to a decrease in the hydrogen surface fugacity produced through electronic modifications of Pt by adsorbed sulfur atoms. 23 refs., 8 figs., 3 tabs.

• OSTI ID: 471623
• Journal Information: Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 161; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
40 CHEMISTRY
ALUMINIUM OXIDES
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CATALYTIC REFORMING
COKE
HEPTANE
HETEROGENEOUS CATALYSIS
PLATINUM
RHENIUM
SULFUR