US5149512A
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US
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Catalytic reduction of NOx using methane in the presence of oxygen
Assignee: Air Products and Chemicals Inc
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Filing: 1991-08-01
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Granted: 1992-09-22
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Expires: 2011-08-01
Abstract
Abstract The invention describes a catalytic process for destroying NOx from oxygen-containing combustion products wherein methane serves as a reductant. The process comprises contacting the NOx-containing combustion products with a desired amount of methane and oxygen in the presence of a metal-exchanged crystalline zeolite having a silicon to aluminum ratio of greater than or equal to about 2.5 under conditions sufficient to effect conversion to gaseous nitrogen, water and carbon oxides. The zeolites are exchanged with a cation selection from the group consisting of cobalt, nickel, iron, chromium, rhodium and manganese.
Inventors
- 👤 Yuejin Li
- 👤 John N. Armor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:56
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/38; F; F01; F01N; F01N3/00; F01N3/08; F01N3/10; F01N3/18; F01N3/20; F01N3/206; F01N3/2066; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; B01D53/92; B01D53/94; B01D53/9404; B01D53/9409; B01D53/9413; B01D53/9418; F01N13/00; F01N13/009; B01D2251/00; B01D2251/20; B01D2251/208; B01D2255/00; B01D2255/10; B01D2255/102; B01D2255/1025; B01D2255/20; B01D2255/207; B01D2255/2073; B01D2255/20738; B01D2255/20746; B01D2255/20753; B01D2255/20784; B01D2255/50; F01N2610/00; F01N2610/03; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
75 words
A process for destroying nitrogen oxides comprising: reacting the nitrogen oxides, methane and oxygen in the presence of a crystalline zeolite having a silicon to aluminum ratio of greater than or equal to about 2.5 wherein the zeolite is exchanged with an effective amount of a cation selected from the group consisting of cobalt, nickel, iron, chromium, rhodium and manganese under conditions sufficient to convert the nitrogen oxides to gaseous nitrogen, water and carbon oxides.
Claim 2
Dependent Claim
75 words
A process for destroying nitrogen oxides comprising: reacting the nitrogen oxides, methane and oxygen in the presence of a crystalline zeolite having a silicon to aluminum ratio of greater than or equal to about 2.5 wherein the zeolite is exchanged with an effective amount of a cation selected from the group consisting of cobalt, nickel, iron, chromium, rhodium and manganese under conditions sufficient to convert the nitrogen oxides to gaseous nitrogen, water and carbon oxides.
Claim 3
Dependent Claim
30 words
The process according to claim 1 wherein the zeolite is exchanged with from 0.1 to about 15 wt% of the cation based upon the total weight of the exchanged zeolite.
Claim 4
Dependent Claim
23 words
The process according to claim 2 wherein the crystalline zeolite is selected from the group consisting of natural and synthetic zeolites and mordenites.
Claim 5
Dependent Claim
17 words
The process according to claim 3 wherein the methane/nitrogen oxide ratio ranges from about 0.2 to 10.
Claim 6
Dependent Claim
27 words
The process according to claim 4 wherein the reacting is conducted at temperatures ranging from 250° to 600° C. and pressures ranging from 1 to 300 atmospheres.
Claim 7
Dependent Claim
32 words
The process according to claim 5 wherein the reacting is conducted in a fixed bed reactor with a gas hourly space velocity ranging from 1,000 hr -1 to 100,000 hr -1 .
Claim 8
Dependent Claim
53 words
The process according to claim 6 wherein the exchanged zeolite is subsequently exchanged with from 0.01 to about 2 wt%, based upon total weight of the exchanged zeolite, of an additional metal selected from the third period transition metals or Groups 5, 6, 7 and 11 of the Periodic Table of the Elements.
Claim 9
Dependent Claim
51 words
The process according to claim 6 where the metal-exchanged zeolite is impregnated with from 0.01 wt % to 15 wt %, based upon the total weight of the impregnated metal-exchanged zeolite, of an anionic or neutral species containing a metal selected from Group 5,6, 7 and 11 of the Periodic Table.
Claim 10
Dependent Claim
31 words
The process according to claim 8 wherein the species to be impregnated onto the metal-exchanged zeolite contains a metal selected from the group consisting of niobium, molybdenum, silver, vanadium and manganese.
Claim 11
Dependent Claim
25 words
The process according to claim 6 wherein a stoichiometric excess of oxygen, based upon the nitrogen oxides, is reacted with the nitrogen oxides and methane.
Claim 12
Dependent Claim
30 words
The process according to claim 1 wherein the nitrogen oxides are present in combustion products generated from the group consisting of utility boilers, industrial boilers, gas turbines and stationary engines.
Claim 13
Dependent Claim
18 words
The process according to claim 1 further comprising injecting methane from an external source into the combustion products.
Claim 14
Dependent Claim
61 words
A process for destroying nitrogen oxides comprising: reacting the nitrogen oxides, methane and oxygen in the presence of a MOR structure type zeolite which is exchanged with an effective amount of a cation selected from the group consisting of cobalt, nickel, iron, chromium, rhodium and manganese under conditions sufficient to convert the nitrogen oxides to gaseous nitrogen, water and carbon oxides.
Claim 15
Dependent Claim
61 words
A process for destroying nitrogen oxides comprising: reacting the nitrogen oxides, methane and oxygen in the presence of a MOR structure type zeolite which is exchanged with an effective amount of a cation selected from the group consisting of cobalt, nickel, iron, chromium, rhodium and manganese under conditions sufficient to convert the nitrogen oxides to gaseous nitrogen, water and carbon oxides.
Claim 16
Dependent Claim
30 words
The process according to claim 13 wherein the zeolite is exchanged with from 0.1 to about 15 wt% of the cation based upon the total weight of the exchanged zeolite.
Claim 17
Dependent Claim
17 words
The process according to claim 14 wherein the methane/nitrogen oxide ratio ranges from about 0.3 to 4.
Claim 18
Dependent Claim
27 words
The process according to claim 15 wherein the process is conducted at temperatures ranging from 350° to 500° C. and pressures ranging from 1 to 300 atmospheres.
Claim 19
Dependent Claim
32 words
The process according to claim 14 wherein the process is run in a fixed bed reactor with a gas hourly space velocity ranging from 7,500 hr -1 to 30,000 hr -1 .
Claim 20
Dependent Claim
54 words
The process according to claim 15 wherein the metal-exchanged zeolite is subsequently exchanged with from 0.01 to about 2 wt %, based upon total weight of the exchanged zeolite, of an additional metal selected from the third period transition metals or Groups 5, 6, 7 and 11 of the Periodic Table of the Elements.
Claim 21
Dependent Claim
27 words
The process according to claim 18 wherein the metal-exchanged zeolite is further exchanged with a cation selected from the group consisting of chromium, nickel, manganese and silver.
Claim 22
Dependent Claim
54 words
The process according to claim 17 wherein the metal-exchanged zeolite is impregnated with 0.1 wt % to 8 wt %, based upon the total weight of the impregnated metal-exchanged zeolite, of an anionic or neutral species containing a metal selected from Group 5, 6, 7 and 11 of the Periodic Table of the Elements.
Claim 23
Dependent Claim
30 words
The process according to claim 20 wherein the species to be impregnated onto the zeolite contains a metal selected from the group consisting of niobium, molybdenum, silver, vanadium and manganese.
Claim 24
Dependent Claim
30 words
The process according to claim 13 wherein the nitrogen oxides are present in combustion products generated from the group consisting of utility boilers, industrial boilers, gas turbines and stationary engines.
Claim 25
Dependent Claim
18 words
The process according to claim 13 further comprising injecting methane from an external source into the combustion products.
Claim 26
Dependent Claim
61 words
A process for destroying nitrogen oxides comprising: reacting the nitrogen oxides, methane and oxygen in the presence of a MFI structure type zeolite which is exchanged with an effective amount of a cation selected from the group consisting of cobalt, nickel, iron, chromium, rhodium and manganese under conditions sufficient to convert the nitrogen oxides to gaseous nitrogen, water and carbon oxides.
Claim 27
Dependent Claim
61 words
A process for destroying nitrogen oxides comprising: reacting the nitrogen oxides, methane and oxygen in the presence of a MFI structure type zeolite which is exchanged with an effective amount of a cation selected from the group consisting of cobalt, nickel, iron, chromium, rhodium and manganese under conditions sufficient to convert the nitrogen oxides to gaseous nitrogen, water and carbon oxides.
Claim 28
Dependent Claim
31 words
The process according to claim 24 wherein the zeolite is exchanged with from 0.1 to about 15 wt % of the cation based upon the total weight of the exchanged zeolite.
Claim 29
Dependent Claim
17 words
The process according to claim 25 wherein the zeolite is selected from the group consisting of ZSM-5.
Claim 30
Dependent Claim
17 words
The process according to claim 26 wherein the methane/nitrogen oxide ratio ranges from about 0.3 to 4.
Claim 31
Dependent Claim
27 words
The process according to claim 27 wherein the process is conducted at temperatures ranging from 350° to 500° C. and pressures ranging from 1 to 300 atmospheres.
Claim 32
Dependent Claim
32 words
The process according to claim 28 wherein the process is run in a fixed bed reactor with a gas hourly space velocity ranging from 7,500 hr -1 to 30,000 hr -1 .
Claim 33
Dependent Claim
54 words
The process according to claim 28 wherein the metal-exchanged zeolite is subsequently exchanged with from 0.01 to about 2 wt %, based upon total weight of the exchanged zeolite, of an additional metal selected from the third period transition metals or Groups 5, 6, 7 and 11 of the Periodic Table of the Elements.
Claim 34
Dependent Claim
27 words
The process according to claim 30 wherein the metal-exchanged zeolite is further exchanged with a cation selected from the group consisting of chromium, nickel, manganese and silver.
Claim 35
Dependent Claim
54 words
The process according to claim 29 wherein the metal-exchanged zeolite is impregnated with 0.1 wt % to 8 wt %, based upon the total weight of the impregnated metal-exchanged zeolite, of an anionic or neutral species containing a metal selected from Group 5, 6, 7 and 11 of the Periodic Table of the Elements.
Claim 36
Dependent Claim
30 words
The process according to claim 32 wherein the metal-exchanged zeolite is impregnated with a species containing a metal selected from the group consisting of niobium, molybdenum, silver, vanadium and manganese.
Claim 37
Dependent Claim
30 words
The process according to claim 24 wherein the nitrogen oxides are present in combustion products generated from the group consisting of utility boilers, industrial boilers, gas turbines and stationary engines.
Claim 38
Dependent Claim
18 words
The process according to claim 24 further comprising injecting methane from an external source into the combustion products.
References Cited (Backward Citations)
JPS62291258A
Cited
JPS63119850A
Cited
US4869735A
Cited
US4869735B1
Cited
US4867954A
Cited
US5017538A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1995-09-22 | 1996-03-23 | 1996-09-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-22 | 2000-03-23 | 2000-09-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-22 | 2004-03-23 | 2004-09-22 | $7700.00 | Window Closed / Lapsed |