US4867954A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Catalytic reduction of nitrogen oxides
Assignee: Honeywell UOP LLC
•
Filing: 1988-04-07
•
Granted: 1989-09-19
•
Expires: 2008-04-07
Abstract
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.
Inventors
- 👤 Mark T. Staniulis
- 👤 Alan P. Risch
- 👤 James G. Vassilakis
- 👤 Donald F. Best
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:41
CPC Classifications
B; B01; B01J; B01J37/00; B01J37/06; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; B01D53/92; B01D53/94; B01D53/9404; B01D53/9409; B01D53/9413; B01D53/9418; B01J29/00; B01J29/04; B01J29/06; B01J29/08; B01J29/084; B01J29/70; B01D2251/00; B01D2251/20; B01D2251/206; B01D2251/2062; B01D2255/00; B01D2255/20; B01D2255/202; B01D2255/2022; B01D2255/207; B01D2255/20761; B01D2255/50; B01J2229/00; B01J2229/30; B01J2229/42; Y; Y02; Y02C; Y02C20/00; Y02C20/10
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
146 words
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 selected from a zeolitic or silica molecular sieve or mixtures thereof at ®effective reduction conditions in which the amount of ammonia in said method is excessive over the stoichimetric amount necessary for catalytically reducing one or more nitrogen oxides from said gaseous stream, wherein said microporous molecular sieve composition is (i) acid treated with an inorganic or organic acid, (ii) hydrogen-forming cation exchanged and (iii) 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.
Claim 2
Independent Claim
146 words
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 selected from a zeolitic or silica molecular sieve or mixtures thereof at ®effective reduction conditions in which the amount of ammonia in said method is excessive over the stoichimetric amount necessary for catalytically reducing one or more nitrogen oxides from said gaseous stream, wherein said microporous molecular sieve composition is (i) acid treated with an inorganic or organic acid, (ii) hydrogen-forming cation exchanged and (iii) 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.
Claim 3
Dependent Claim
32 words
The method of claim 1 wherein said microporous molecular sieve composition is acid treated with an acid selected form nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, formic acid and trichloroacetic acid.
Claim 4
Dependent Claim
17 words
The method of claim 1 wherein said microporous molecular sieve composition is acid treated with nitric acid.
Claim 5
Dependent Claim
30 words
The method of claim 1 wherein said microporous molecular sieve composition is hydrogen-forming cation exchanged with a hydrogen-forming cation selected from NH 4 + , H + or quaternary ammonium.
Claim 6
Dependent Claim
17 words
The method of claim 1 wherein said microporous molecular sieve composition is hydrogen-forming cation exchanged with NH4
Claim 7
Dependent Claim
35 words
The method of claim 1 wherein said microporous molecular sieve composition is metal cation exchanged with a metal selected from copper, cobalt, vanadium, chromium, tungsten, nickel, platinum, palladium, manganese, molybdenum, rhodium, magnesium, aluminum and iron.
Claim 8
Dependent Claim
17 words
The method of claim 1 wherein said microporous molecular sieve composition is metal cation exchanged with copper.
Claim 9
Dependent Claim
26 words
The method of claim 1 wherein said microporous molecular sieve composition is simultaneously acid treated with an inorganic or organic acid and hydrogen forming cation exchanged.
Claim 10
Dependent Claim
27 words
The method of claim 1 wherein said microporous molecular sieve composition is hydrogen forming cation exchanged prior to being acid treated with an inorganic or organic acid.
Claim 11
Dependent Claim
27 words
The method of claim 1 wherein said microporous molecular sieve composition is hydrothermally treated with steam prior to being acid treated with an inorganic or organic acid.
Claim 12
Dependent Claim
31 words
The method of claim 1 wherein said microporous molecular sieve composition is hydrogen-forming cation exchanged and hydrothermally treated with steam prior to being acid treated with an inorganic or organic acid.
Claim 13
Dependent Claim
24 words
The method of claim 1 wherein said microporous molecular sieve composition is calcined prior to being acid treated with an inorganic or organic acid.
Claim 14
Dependent Claim
16 words
The method of claim 1 wherein said microporous molecular sieve composition is a zeolitic molecular sieve.
Claim 15
Dependent Claim
14 words
The method of claim 1 wherein said microporous molecular sieve composition is a zeolite.
Claim 16
Dependent Claim
13 words
The method of claim 1 wherein said microporous molecular sieve composition is LZ-105.
Claim 17
Dependent Claim
19 words
The method of claim 1 wherein said microporous molecular sieve composition is a silica) molecular sieve or mixture thereof.
Claim 18
Dependent Claim
13 words
The method of claim 1 wherein said microporous molecular sieve composition is silicalite.
Claim 19
Dependent Claim
37 words
The method of claim 1 wherein said microporous molecular sieve composition is a zeolitic or silica molecular sieve having a SiO 2 /Al 2 O 3 molar ratio of from greater than about 6.5 to about 100.
Claim 20
Dependent Claim
35 words
The method of claim 1 wherein said microporous molecular sieve composition is a zeolitic or silica molecular sieve having a SiO 2 /Al 2 O 3 molar ratio of from about 100 to about 250.
Claim 21
Dependent Claim
18 words
The method of claim 1 wherein said microporous molecular sieve composition is supported in an inorganic oxide matrix.
Claim 22
Dependent Claim
13 words
The method of claim 20 wherein the inorganic oxide matrix is predominantly silica.
Claim 23
Dependent Claim
25 words
The method of claim 1 wherein said microporous molecular sieve composition is in the form of a plate shape, cylindrical shape or honeycomb monolith shape.
Claim 24
Dependent Claim
50 words
The method of claim 1 wherein said microporous molecular sieve composition is in the form of a honeycomb monolith shape and the gaseous stream is passed through many passages which are respectively substantially straight and parallel and which are formed by partitioning with at least a portion of said composition.
Claim 25
Dependent Claim
17 words
The method of claim 1 wherein the gaseous stream contains at least nitrogen oxide and sulfur dioxide.
Claim 26
Dependent Claim
19 words
The method of claim 1 wherein the gaseous stream contains at least nitrogen oxide, nitrogen dioxide and sulfur dioxide.
Claim 27
Dependent Claim
34 words
The method of claim 1 in which ammonia is present in an amount sufficient to result in a molar ratio of said ammonia to said nitrogen oxides of from about 1.05:1 to about 1.50:1.
Claim 28
Dependent Claim
31 words
The method of claim 1 wherein said gaseous stream and ammonia are contacted with said microporous molecular sieve composition at a temperature of from about 200° C. to about 650° C.
Claim 29
Dependent Claim
30 words
The method of claim 1 wherein said gaseous stream and ammonia are contacted with said microporous molecular sieve composition at a pressure of from about atmospheric to about 10 psig.
Claim 30
Dependent Claim
31 words
The method of claim 1 wherein said gaseous stream and ammonia are passed through said microporous molecular sieve composition at a space velocity of from about 1000 to about 150,000 hr-1.
Claim 31
Independent Claim
137 words
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 non-zeolitic 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 non-zeolitic molecular sieve composition is (i) acid treated with an inorganic or organic acid, (ii) hydrogen-forming cation exchanged and (iii) metal cation exchanged, prior to said contracting 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.
Claim 32
Independent Claim
137 words
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 non-zeolitic 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 non-zeolitic molecular sieve composition is (i) acid treated with an inorganic or organic acid, (ii) hydrogen-forming cation exchanged and (iii) metal cation exchanged, prior to said contracting 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.
References Cited (Backward Citations)
US4046888A
Cited
US4473535A
Cited
US4157375A
Cited
GB2039863A
Cited
US4297328A
Cited
US4738941A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-09-18 | 1993-03-20 | 1993-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-18 | 1997-03-20 | 1997-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-18 | 2001-03-20 | 2001-09-19 | $7700.00 | Window Closed / Lapsed |