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Title: Deactivation model with residual activity of study thioresistance and thiotolerance of naphtha reforming catalysts

Abstract

The relative sensitivity to sulfur poisoning of typical commercially employed naphtha reforming catalysts was studied using a cyclohexane dehydrogenation as test reaction and thiophene as the poisoning molecule. Monometallic Pt/Al[sub 2]O[sub 3] and bimetallic Pt-Re/Al[sub 2]O[sub 3], Pt-Ir/Al[sub 2]O[sub 3], Pt-Ge/Al[sub 2]O[sub 3], and Pt-Sn/Al[sub 2]O[sub 3] catalysts were used. A deactivation model with residual activity (DMRA) was employed for determining both the thiotolerance and the thioresistance of the catalysts. The DMRA model was developed by using Langmuir-Hinshelwood kinetics and assuming the rate-determining step in the poisoning mechanism to be reversible. The thiotolerance was in the order Pt-Ge > Pt-Ir [congruent] Pt [congruent] Pt-Sn > Pt-Re. According to DMRA equations, the thiotolerance decreases when K[sub s], the adsorption equilibrium constant of H[sub 2]S on the catalysts, increases. This DMRA model prediction was verified by measuring the quantities of total and irreversibly held sulfur following exposure of the catalysts to H[sub 2]/H[sub 2]S mixtures. The thioresistance decreased in the sequence Pt-Ge > Pt-Ir [congruent] Pt > Pt-Re > Pt-Sn. From DMRA equations it was established that the thioresistance is primarily a function of k[sub p], the reaction rate constant for the hydrogenolysis of adsorbed thiophene; the higher the k[sub p] value,more » the lower the catalyst thioresistance. Bimetallic Pt-Ge/Al[sub 2]O[sub 3] was the most thioresistant and thiotolerant catalyst. This superior performance is explained by assuming that upon reduction at 773 K a fraction of the Ge cations is reduced and forms bimetallic Pt-Ge particles. The formation of Pt-Ge clusters increases the electrophilic character of platinum, thereby weakening the strength of the S-Pt bond and reducing the amount of irreversibly held sulfur on platinum. 57 refs., 5 figs., 5 tabs.« less

Authors:
; ;  [1];  [2]
  1. (Instituto de Investigaciones n Catalisis y Petroquimica-INCAPE, Santa Fe (Argentina))
  2. (Universidad de Zaragoza (Spain))
Publication Date:
OSTI Identifier:
7035035
Resource Type:
Journal Article
Journal Name:
Journal of Catalysis; (United States)
Additional Journal Information:
Journal Volume: 146:1; Journal ID: ISSN 0021-9517
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 02 PETROLEUM; ALUMINIUM OXIDES; CATALYTIC EFFECTS; GERMANIUM; IRIDIUM; PLATINUM; RHENIUM; SULFUR; CHEMISORPTION; TIN; ABSORPTION SPECTROSCOPY; CATALYST SUPPORTS; CATALYSTS; CATALYTIC REFORMING; CHEMICAL REACTION KINETICS; CYCLOHEXANE; DEHYDROGENATION; ALKANES; ALUMINIUM COMPOUNDS; CHALCOGENIDES; CHEMICAL REACTIONS; CYCLOALKANES; ELEMENTS; HYDROCARBONS; KINETICS; METALS; NONMETALS; ORGANIC COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; PLATINUM METALS; REACTION KINETICS; REFORMER PROCESSES; SEPARATION PROCESSES; SORPTION; SPECTROSCOPY; TRANSITION ELEMENTS; 400201* - Chemical & Physicochemical Properties; 020400 - Petroleum- Processing

Citation Formats

Borgna, A., Garetto, T.F., Apesteguia, C.R., and Monzon, A. Deactivation model with residual activity of study thioresistance and thiotolerance of naphtha reforming catalysts. United States: N. p., 1994. Web. doi:10.1016/0021-9517(94)90009-4.
Borgna, A., Garetto, T.F., Apesteguia, C.R., & Monzon, A. Deactivation model with residual activity of study thioresistance and thiotolerance of naphtha reforming catalysts. United States. doi:10.1016/0021-9517(94)90009-4.
Borgna, A., Garetto, T.F., Apesteguia, C.R., and Monzon, A. Tue . "Deactivation model with residual activity of study thioresistance and thiotolerance of naphtha reforming catalysts". United States. doi:10.1016/0021-9517(94)90009-4.
@article{osti_7035035,
title = {Deactivation model with residual activity of study thioresistance and thiotolerance of naphtha reforming catalysts},
author = {Borgna, A. and Garetto, T.F. and Apesteguia, C.R. and Monzon, A.},
abstractNote = {The relative sensitivity to sulfur poisoning of typical commercially employed naphtha reforming catalysts was studied using a cyclohexane dehydrogenation as test reaction and thiophene as the poisoning molecule. Monometallic Pt/Al[sub 2]O[sub 3] and bimetallic Pt-Re/Al[sub 2]O[sub 3], Pt-Ir/Al[sub 2]O[sub 3], Pt-Ge/Al[sub 2]O[sub 3], and Pt-Sn/Al[sub 2]O[sub 3] catalysts were used. A deactivation model with residual activity (DMRA) was employed for determining both the thiotolerance and the thioresistance of the catalysts. The DMRA model was developed by using Langmuir-Hinshelwood kinetics and assuming the rate-determining step in the poisoning mechanism to be reversible. The thiotolerance was in the order Pt-Ge > Pt-Ir [congruent] Pt [congruent] Pt-Sn > Pt-Re. According to DMRA equations, the thiotolerance decreases when K[sub s], the adsorption equilibrium constant of H[sub 2]S on the catalysts, increases. This DMRA model prediction was verified by measuring the quantities of total and irreversibly held sulfur following exposure of the catalysts to H[sub 2]/H[sub 2]S mixtures. The thioresistance decreased in the sequence Pt-Ge > Pt-Ir [congruent] Pt > Pt-Re > Pt-Sn. From DMRA equations it was established that the thioresistance is primarily a function of k[sub p], the reaction rate constant for the hydrogenolysis of adsorbed thiophene; the higher the k[sub p] value, the lower the catalyst thioresistance. Bimetallic Pt-Ge/Al[sub 2]O[sub 3] was the most thioresistant and thiotolerant catalyst. This superior performance is explained by assuming that upon reduction at 773 K a fraction of the Ge cations is reduced and forms bimetallic Pt-Ge particles. The formation of Pt-Ge clusters increases the electrophilic character of platinum, thereby weakening the strength of the S-Pt bond and reducing the amount of irreversibly held sulfur on platinum. 57 refs., 5 figs., 5 tabs.},
doi = {10.1016/0021-9517(94)90009-4},
journal = {Journal of Catalysis; (United States)},
issn = {0021-9517},
number = ,
volume = 146:1,
place = {United States},
year = {1994},
month = {3}
}