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Title: Plasma-assisted catalytic storage reduction system

Abstract

A two-stage method for NO.sub.x reduction in an oxygen-rich engine exhaust comprises a plasma oxidative stage and a storage reduction stage. The first stage employs a non-thermal plasma treatment of NO.sub.x gases in an oxygen-rich exhaust and is intended to convert NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons. The second stage employs a lean NO.sub.x trap to convert such NO.sub.2 to environmentally benign gases that include N.sub.2, CO.sub.2, and H.sub.2 O. By preconverting NO to NO.sub.2 in the first stage with a plasma, the efficiency of the second stage for NO.sub.x reduction is enhanced. For example, an internal combustion engine exhaust is connected by a pipe to a first chamber in which a non-thermal plasma converts NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons, such as propene. A flow of such hydrocarbons (C.sub.x H.sub.y) is input from usually a second pipe into at least a portion of the first chamber. The NO.sub.2 from the plasma treatment proceeds to a storage reduction catalyst (lean NO.sub.x trap) that converts NO.sub.2 to N.sub.2, CO.sub.2, and H.sub.2 O, and includes a nitrate-forming catalytic site. The hydrocarbons and NO.sub.x are simultaneously reduced while passing through the lean-NO.sub.x trap catalyst. Themore » method allows for enhanced NO.sub.x reduction in vehicular engine exhausts, particularly those having relatively high sulfur contents.

Inventors:
 [1];  [2];  [3];  [3]
+ Show Inventor Affiliations
  1. San Ramon, CA
  2. Fremont, CA
  3. Livermore, CA
Issue Date:
Research Org.:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
OSTI Identifier:
874355
Patent Number(s):
6374595
Assignee:
The Regents of the University of California (Oakland, CA)
Patent Classifications (CPCs):
B - PERFORMING OPERATIONS B01 - PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL B01D - SEPARATION
F - MECHANICAL ENGINEERING F01 - MACHINES OR ENGINES IN GENERAL F01N - GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL
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DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
plasma-assisted; catalytic; storage; reduction; two-stage; method; nosubx; oxygen-rich; engine; exhaust; plasma; oxidative; stage; employs; non-thermal; treatment; gases; intended; convert; nosub2; presence; osub2; hydrocarbons; lean; trap; environmentally; benign; nsub2; cosub2; hsub2; preconverting; efficiency; enhanced; example; internal; combustion; connected; pipe; chamber; converts; propene; flow; csubx; hsuby; input; portion; proceeds; catalyst; nitrate-forming; site; simultaneously; reduced; passing; lean-nosubx; allows; vehicular; exhausts; sulfur; contents; internal combustion; combustion engine; engine exhaust; non-thermal plasma; /60/422/

Citation Formats

Penetrante, Bernardino M, Vogtlin, George E, Merritt, Bernard T, and Brusasco, Raymond M. Plasma-assisted catalytic storage reduction system. United States: N. p., 2002. Web.
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Penetrante, Bernardino M, Vogtlin, George E, Merritt, Bernard T, & Brusasco, Raymond M. Plasma-assisted catalytic storage reduction system. United States.
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Penetrante, Bernardino M, Vogtlin, George E, Merritt, Bernard T, and Brusasco, Raymond M. Tue . "Plasma-assisted catalytic storage reduction system". United States. https://www.osti.gov/servlets/purl/874355.
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@article{osti_874355,
title = {Plasma-assisted catalytic storage reduction system},
author = {Penetrante, Bernardino M and Vogtlin, George E and Merritt, Bernard T and Brusasco, Raymond M},
abstractNote = {A two-stage method for NO.sub.x reduction in an oxygen-rich engine exhaust comprises a plasma oxidative stage and a storage reduction stage. The first stage employs a non-thermal plasma treatment of NO.sub.x gases in an oxygen-rich exhaust and is intended to convert NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons. The second stage employs a lean NO.sub.x trap to convert such NO.sub.2 to environmentally benign gases that include N.sub.2, CO.sub.2, and H.sub.2 O. By preconverting NO to NO.sub.2 in the first stage with a plasma, the efficiency of the second stage for NO.sub.x reduction is enhanced. For example, an internal combustion engine exhaust is connected by a pipe to a first chamber in which a non-thermal plasma converts NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons, such as propene. A flow of such hydrocarbons (C.sub.x H.sub.y) is input from usually a second pipe into at least a portion of the first chamber. The NO.sub.2 from the plasma treatment proceeds to a storage reduction catalyst (lean NO.sub.x trap) that converts NO.sub.2 to N.sub.2, CO.sub.2, and H.sub.2 O, and includes a nitrate-forming catalytic site. The hydrocarbons and NO.sub.x are simultaneously reduced while passing through the lean-NO.sub.x trap catalyst. The method allows for enhanced NO.sub.x reduction in vehicular engine exhausts, particularly those having relatively high sulfur contents.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2002},
month = {1}
}
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Works referenced in this record:

Reduction of Nitric Oxide in Flue Gases by Point to Plane Corona Discharge with Catalytical Coatings on the Plane Electrode
journal, July 1990

Recent Progress in NOx Trap Technology
conference, February 1998

Highly Durable NOx Reduction System and Catalysts for NOx Storage Reduction System
conference, February 1998

The new concept 3-way catalyst for automotive lean-burn engine: NOx storage and reduction catalyst
journal, January 1996

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