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Pre-converted nitric oxide gas in catalytic reduction system

Patent ·
OSTI ID:872238
 [1];  [1];  [2];  [3]
  1. Livermore, CA
  2. San Ramon, CA
  3. Fremont, CA
+ Show Author Affiliations

A two-stage catalyst comprises an oxidative first stage and a reductive second stage. The first stage is intended to convert NO to NO.sub.2 in the presence of O.sub.2. The second stage serves to convert NO.sub.2 to environmentally benign gases that include N2, CO2, and H.sub.2 O. By preconverting NO to NO.sub.2 in the first stage, 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. An oxidizing first catalyst converts NO to NO.sub.2 in the presence of O.sub.2 and includes platinum/alumina, e.g., Pt/Al.sub.2 O.sub.3 catalyst. A flow of hydrocarbons (C.sub.x H.sub.y) is input from a pipe into a second chamber. For example, propene can be used as a source of hydrocarbons. The NO.sub.2 from the first catalyst mixes with the hydrocarbons in the second chamber. The mixture proceeds to a second reduction catalyst that converts NO.sub.2 to N2, CO2, and H.sub.2 O, and includes a gamma-alumina .gamma.-Al.sub.2 O.sub.3. The hydrocarbons and NO.sub.x are simultaneously reduced while passing through the second catalyst.

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 5891409
OSTI ID:
872238
Country of Publication:
United States
Language:
English

References (8)

Comparison of electrical discharge techniques for nonthermal plasma processing of NO in N/sub 2/ journal January 1995
Oxidation of NO to NO2 on a Pt-MFI zeolite and subsequent reduction of NOx by C2H4 on an In-MFI zeolite: a novel de-NOx strategy in excess oxygen journal January 1997
Transition metal-promoted silica and alumina catalysts for the selective reduction of nitrogen monoxide with propane journal August 1991
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
On the role of nitrogen dioxide in the mechanism of the selective reduction of NOx over Cu-ZSM-5 zeolite journal June 1993
Selective reduction of nitrogen oxides with hydrocarbons over solid acid catalysts in oxygen-rich atmospheres journal January 1990
Selective reduction of nitrogen monoxide with propane over alumina and HZSM-5 zeolite journal January 1991

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