Catalytic reduction of nitrogen oxides
US4867954A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 7, 1988 |
| Grant date | Sep 19, 1989 |
| Priority date | — |
| Expiry date | Apr 7, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02C20/10
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
This invention relates to a method for catalytically reducing one or more nitrogen oxides from a gaseous stream containing one or more nitrogen oxides and optionally one or more sulfur oxides which comprises contacting said gaseous stream and ammonia with a microporous molecular sieve composition at effective reduction conditions in which the amount of ammonia in said method is excessive over the stoichiometric amount necessary for catalytically reducing one or more nitrogen oxides from said gaseous stream, wherein said microporous molecular sieve composition is (i) optionally acid treated with an inorganic or organic acid, (ii) hydrogen-forming cation exchanged and (iii) optionally metal cation exchanged, prior to said contacting in said method, and wherein at least a portion of excessive ammonia in said method is oxidized without substantial adverse effect on catalytically reducing one or more nitrogen oxides from said gaseous stream.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.