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Title: Effect of alumina incorporation on the sulfur tolerance of the dual-catalyst aftertreatment system for reduction of nitrogen oxides under lean conditions

Abstract

Presence of sulfur or sulfur additives in natural gas lead to the formation of sulfur dioxide in the exhaust stream of natural gas-fired lean-burn engines. The sulfur tolerance and hydrothermal stability of the dual-catalyst aftertreatment system comprising a reduction catalyst (palladium supported on sulfated zirconia- Pd/SZ) and an oxidation catalyst (cobalt oxide supported on ceria- CoO x/CeO 2) for NOx reduction under lean-burn conditions has been tested under simulated engine exhaust conditions. Alumina-incorporated Pd/SZ (Pd/SZ(Alumina)) reduction catalyst as part of the dual catalyst bed demonstrated superior sulfur tolerance in the presence of 5 ppm SO 2 in the feed. The ratio of the reduction to oxidation catalyst was also seen to affect the hydrothermal stability under wet conditions with SO 2 in the reaction medium. The effect of hydrocarbon and water concentration in the reaction mixture on the sulfur tolerance of the dual-catalyst bed was studied. Increasing the reaction temperature from 450°C to 500°C demonstrated very stable NO x conversion and improved CH 4 conversions when the dual-catalyst bed was kept on-stream for 40 h -1. X-ray photoelectron spectroscopy on samples poisoned with SO 2 ex-situ revealed the deposition of surface sulfates on the Pd/SZ catalyst samples and a combinationmore » of sulfates and sulfites on the CoO x/CeO 2 on treatment with SO 2. The presence of alumina in the Pd/SZ sample protects the support from SO 2 poisoning as the oxidation state of the zirconia support remained largely unchanged on poisoning while in the CoO x/CeO 2 sample, sulfur poisoning likely affects the cerium redox cycle (Ce 3+-Ce 4+). 27Al magic angle spinning nuclear magnetic resonance (MAS NMR) revealed redistribution of the octahedral and tetrahedral Al-O coordination on SO 2 poisoning. Due to association with deposited sulfates on the catalyst, shielding effect on the Al nuclei resulted in an increased octahedral Al-O coordination in the poisoned sample.« less

Authors:
ORCiD logo [1];  [2];  [2];  [2];  [2]
  1. The Ohio State Univ., Columbus, OH (United States). William G. Lowrie Dept. of Chemical and Biomolecular Engineering; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. The Ohio State Univ., Columbus, OH (United States). William G. Lowrie Dept. of Chemical and Biomolecular Engineering
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); The Ohio State Univ., Columbus, OH (United States)
Sponsoring Org.:
USDOE; Caterpillar Inc., Peoria, IL (United States)
OSTI Identifier:
1471840
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Catalysis Today
Additional Journal Information:
Journal Volume: 320; Journal ID: ISSN 0920-5861
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 33 ADVANCED PROPULSION SYSTEMS; NOx reduction; Lean-burn; SO2 tolerance; XPS; 27Al MAS NMR

Citation Formats

Sinha Majumdar, Sreshtha, Alexander, Anne-Marie, Gawade, Preshit, Celik, Gokhan, and Ozkan, Umit S. Effect of alumina incorporation on the sulfur tolerance of the dual-catalyst aftertreatment system for reduction of nitrogen oxides under lean conditions. United States: N. p., 2018. Web. doi:10.1016/j.cattod.2018.01.027.
Sinha Majumdar, Sreshtha, Alexander, Anne-Marie, Gawade, Preshit, Celik, Gokhan, & Ozkan, Umit S. Effect of alumina incorporation on the sulfur tolerance of the dual-catalyst aftertreatment system for reduction of nitrogen oxides under lean conditions. United States. doi:10.1016/j.cattod.2018.01.027.
Sinha Majumdar, Sreshtha, Alexander, Anne-Marie, Gawade, Preshit, Celik, Gokhan, and Ozkan, Umit S. Wed . "Effect of alumina incorporation on the sulfur tolerance of the dual-catalyst aftertreatment system for reduction of nitrogen oxides under lean conditions". United States. doi:10.1016/j.cattod.2018.01.027. https://www.osti.gov/servlets/purl/1471840.
@article{osti_1471840,
title = {Effect of alumina incorporation on the sulfur tolerance of the dual-catalyst aftertreatment system for reduction of nitrogen oxides under lean conditions},
author = {Sinha Majumdar, Sreshtha and Alexander, Anne-Marie and Gawade, Preshit and Celik, Gokhan and Ozkan, Umit S.},
abstractNote = {Presence of sulfur or sulfur additives in natural gas lead to the formation of sulfur dioxide in the exhaust stream of natural gas-fired lean-burn engines. The sulfur tolerance and hydrothermal stability of the dual-catalyst aftertreatment system comprising a reduction catalyst (palladium supported on sulfated zirconia- Pd/SZ) and an oxidation catalyst (cobalt oxide supported on ceria- CoOx/CeO2) for NOx reduction under lean-burn conditions has been tested under simulated engine exhaust conditions. Alumina-incorporated Pd/SZ (Pd/SZ(Alumina)) reduction catalyst as part of the dual catalyst bed demonstrated superior sulfur tolerance in the presence of 5 ppm SO2 in the feed. The ratio of the reduction to oxidation catalyst was also seen to affect the hydrothermal stability under wet conditions with SO2 in the reaction medium. The effect of hydrocarbon and water concentration in the reaction mixture on the sulfur tolerance of the dual-catalyst bed was studied. Increasing the reaction temperature from 450°C to 500°C demonstrated very stable NOx conversion and improved CH4 conversions when the dual-catalyst bed was kept on-stream for 40 h-1. X-ray photoelectron spectroscopy on samples poisoned with SO2 ex-situ revealed the deposition of surface sulfates on the Pd/SZ catalyst samples and a combination of sulfates and sulfites on the CoOx/CeO2 on treatment with SO2. The presence of alumina in the Pd/SZ sample protects the support from SO2 poisoning as the oxidation state of the zirconia support remained largely unchanged on poisoning while in the CoOx/CeO2 sample, sulfur poisoning likely affects the cerium redox cycle (Ce3+-Ce4+). 27Al magic angle spinning nuclear magnetic resonance (MAS NMR) revealed redistribution of the octahedral and tetrahedral Al-O coordination on SO2 poisoning. Due to association with deposited sulfates on the catalyst, shielding effect on the Al nuclei resulted in an increased octahedral Al-O coordination in the poisoned sample.},
doi = {10.1016/j.cattod.2018.01.027},
journal = {Catalysis Today},
number = ,
volume = 320,
place = {United States},
year = {2018},
month = {1}
}

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