Reaction Mechanism for m- Xylene Oxidation in the Claus Process by Sulfur Dioxide

Handle URI:
http://hdl.handle.net/10754/594140
Title:
Reaction Mechanism for m- Xylene Oxidation in the Claus Process by Sulfur Dioxide
Authors:
Sinha, Sourab; Raj, Abhijeet; Al Shoaibi, Ahmed S.; Chung, Suk-Ho ( 0000-0001-8782-312X )
Abstract:
In the Claus process, the presence of aromatic contaminants such benzene, toluene, and xylenes (BTX), in the H2S feed stream has a detrimental effect on catalytic reactors, where BTX form soot particles and clog and deactivate the catalysts. Among BTX, xylenes are proven to be most damaging contaminant for catalysts. BTX oxidation in the Claus furnace, before they enter catalyst beds, provides a solution to this problem. A reaction kinetics study on m-xylene oxidation by SO2, an oxidant present in Claus furnace, is presented. The density functional theory is used to study the formation of m-xylene radicals (3-methylbenzyl, 2,6-dimethylphenyl, 2,4-dimethylphenyl, and 3,5-dimethylphenyl) through H-abstraction and their oxidation by SO2. The mechanism begins with SO2 addition on the radicals through an O-atom rather than the S-atom with the release of 180.0-183.1 kJ/mol of reaction energies. This exothermic reaction involves energy barriers in the range 3.9-5.2 kJ/mol for several m-xylene radicals. Thereafter, O-S bond scission takes place to release SO, and the O-atom remaining on aromatics leads to CO formation. Among four m-xylene radicals, the resonantly stabilized 3-methylbenzyl exhibited the lowest SO2 addition and SO elimination rates. The reaction rate constants are provided to facilitate Claus process simulations to find conditions suitable for BTX oxidation. © 2015 American Chemical Society.
KAUST Department:
Clean Combustion Research Center
Citation:
Sinha S, Raj A, Al Shoaibi AS, Chung SH (2015) Reaction Mechanism for m- Xylene Oxidation in the Claus Process by Sulfur Dioxide . The Journal of Physical Chemistry A 119: 9889–9900. Available: http://dx.doi.org/10.1021/acs.jpca.5b06020.
Publisher:
American Chemical Society (ACS)
Journal:
The Journal of Physical Chemistry A
Issue Date:
24-Sep-2015
DOI:
10.1021/acs.jpca.5b06020
PubMed ID:
26334187
Type:
Article
ISSN:
1089-5639; 1520-5215
Sponsors:
King Abdullah University of Science and Technology; The Petroleum Institute University and Research Center[GRC014]
Appears in Collections:
Articles; Clean Combustion Research Center

Full metadata record

DC FieldValue Language
dc.contributor.authorSinha, Souraben
dc.contributor.authorRaj, Abhijeeten
dc.contributor.authorAl Shoaibi, Ahmed S.en
dc.contributor.authorChung, Suk-Hoen
dc.date.accessioned2016-01-19T13:22:30Zen
dc.date.available2016-01-19T13:22:30Zen
dc.date.issued2015-09-24en
dc.identifier.citationSinha S, Raj A, Al Shoaibi AS, Chung SH (2015) Reaction Mechanism for m- Xylene Oxidation in the Claus Process by Sulfur Dioxide . The Journal of Physical Chemistry A 119: 9889–9900. Available: http://dx.doi.org/10.1021/acs.jpca.5b06020.en
dc.identifier.issn1089-5639en
dc.identifier.issn1520-5215en
dc.identifier.pmid26334187en
dc.identifier.doi10.1021/acs.jpca.5b06020en
dc.identifier.urihttp://hdl.handle.net/10754/594140en
dc.description.abstractIn the Claus process, the presence of aromatic contaminants such benzene, toluene, and xylenes (BTX), in the H2S feed stream has a detrimental effect on catalytic reactors, where BTX form soot particles and clog and deactivate the catalysts. Among BTX, xylenes are proven to be most damaging contaminant for catalysts. BTX oxidation in the Claus furnace, before they enter catalyst beds, provides a solution to this problem. A reaction kinetics study on m-xylene oxidation by SO2, an oxidant present in Claus furnace, is presented. The density functional theory is used to study the formation of m-xylene radicals (3-methylbenzyl, 2,6-dimethylphenyl, 2,4-dimethylphenyl, and 3,5-dimethylphenyl) through H-abstraction and their oxidation by SO2. The mechanism begins with SO2 addition on the radicals through an O-atom rather than the S-atom with the release of 180.0-183.1 kJ/mol of reaction energies. This exothermic reaction involves energy barriers in the range 3.9-5.2 kJ/mol for several m-xylene radicals. Thereafter, O-S bond scission takes place to release SO, and the O-atom remaining on aromatics leads to CO formation. Among four m-xylene radicals, the resonantly stabilized 3-methylbenzyl exhibited the lowest SO2 addition and SO elimination rates. The reaction rate constants are provided to facilitate Claus process simulations to find conditions suitable for BTX oxidation. © 2015 American Chemical Society.en
dc.description.sponsorshipKing Abdullah University of Science and Technologyen
dc.description.sponsorshipThe Petroleum Institute University and Research Center[GRC014]en
dc.publisherAmerican Chemical Society (ACS)en
dc.titleReaction Mechanism for m- Xylene Oxidation in the Claus Process by Sulfur Dioxideen
dc.typeArticleen
dc.contributor.departmentClean Combustion Research Centeren
dc.identifier.journalThe Journal of Physical Chemistry Aen
dc.contributor.institutionDepartment of Chemical Engineering, Petroleum Institute, Abu Dhabi, United Arab Emiratesen
kaust.authorChung, Suk-Hoen
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