Plasma-assisted catalytic storage reduction system
- San Ramon, CA
- Fremont, CA
- Livermore, CA
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.
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA
- DOE Contract Number:
- W-7405-ENG-48
- Assignee:
- Regents of University of California (Oakland, CA)
- Patent Number(s):
- US 6038853
- OSTI ID:
- 872920
- Country of Publication:
- United States
- Language:
- English
Recent Progress in NOx Trap Technology
|
conference | February 1998 |
| Non-Thermal Plasma Techniques for Pollution Control | book | |
Reduction of Nitric Oxide in Flue Gases by Point to Plane Corona Discharge with Catalytical Coatings on the Plane Electrode
|
journal | July 1990 |
The new concept 3-way catalyst for automotive lean-burn engine: NOx storage and reduction catalyst
|
journal | January 1996 |
Highly Durable NOx Reduction System and Catalysts for NOx Storage Reduction System
|
conference | February 1998 |
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