US4155986A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dual catalyst nitric oxide reduction
Assignee: Caterpillar Inc
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Filing: 1978-05-18
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Granted: 1979-05-22
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Expires: 1998-05-18
Abstract
Abstract Exhaust gases from diesel and some other engines vary in temperature from about 100° C. to about 800° C. Exhaust is passed along with ammonia to a first reactor wherein the ammonia reduces nitric oxide at temperatures down to a threshold temperature between about 220° C. to about 280° C. Above this threshold temperature the effluent from the reactor is passed to the exhaust. When the first reactor effluent is at a temperature below the threshold temperature, it is passed through a second reactor after intermediate cooling, wherein it contacts an ammonium halide on activated charcoal catalyst at a temperature of 100° C. to 170° C., which catalyst catalizes the low temperature reduction of nitric oxide with ammonia.
Inventors
- 👤 John R. Gladden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:45
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/92; B01D53/94; B01D53/9404; B01D53/9409; F; F01; F01N; F01N13/00; F01N13/009; F01N3/00; F01N3/08; F01N3/10; F01N3/18; F01N3/20; F01N3/2053; F01N3/206; F01N2260/00; F01N2260/02; F01N2260/022; F01N2610/00; F01N2610/02; F02; F02B; F02B3/00; F02B3/06
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
151 words
A process for reducing the nitric oxide content of a combusted gas stream, comprising: contacting a varying temperature combusted gas stream which comprises nitric oxide and ammonia with a first catalyst comprising a porous inorganic oxide nitric oxide reduction catalyst in a first reactor to form a first reactor effluent; determining the temperature of said first reactor effluent; conducting said first reactor effluent to exhaust when said temperature is above a threshold temperature in the range between about 220° C. to about 280° C.; cooling said first reactor effluent when said temperature is below the threshold temperature to a temperature which falls within a range from about 170° C. to about 100° C. to form a cooled effluent; and contacting said cooled effluent with a catalyst comprising an ammonium halide on a porous solid carrier at a temperature which falls within a range from about 170° C. to about 100° C.
Claim 2
Dependent Claim
151 words
A process for reducing the nitric oxide content of a combusted gas stream, comprising: contacting a varying temperature combusted gas stream which comprises nitric oxide and ammonia with a first catalyst comprising a porous inorganic oxide nitric oxide reduction catalyst in a first reactor to form a first reactor effluent; determining the temperature of said first reactor effluent; conducting said first reactor effluent to exhaust when said temperature is above a threshold temperature in the range between about 220° C. to about 280° C.; cooling said first reactor effluent when said temperature is below the threshold temperature to a temperature which falls within a range from about 170° C. to about 100° C. to form a cooled effluent; and contacting said cooled effluent with a catalyst comprising an ammonium halide on a porous solid carrier at a temperature which falls within a range from about 170° C. to about 100° C.
Claim 3
Dependent Claim
48 words
A process as in claim 1 wherein the conducting of said first reactor effluent to exhaust is when said first reactor effluent temperature is above about 260° C.; and the cooling of said first reactor effluent is when said first reactor effluent temperature is below about 260° C.
Claim 4
Dependent Claim
249 words
Apparatus for reducing the nitric oxide content of a combusted gas stream, comprising: means for conducting a varying temperature combusted gas stream from a hydrocarbon burning engine, which gas stream comprises nitric oxide, to a first reactor; means for conducting ammonia to said first reactor; means within said first reactor for catalyzing the reduction of the nitric oxide with the ammonia to form a first reactor effluent, said first reactor catalyzing means comprising a first catalyst which comprises a porous inorganic oxide reduction catalyst for nitric oxide; means for determining the temperature of said first reactor effluent; means for conducting said first reactor effluent to exhaust when said temperature is above a threshold temperature in the range between about 220° C. to about 280° C.; means for conducting said first reactor effluent to cooling means only when said temperature is below said threshold temperature and thereat cooling said effluent with said cooling means to a temperature which falls within a range of about 170° C. to about 100° C. to form a cooled effluent; means for conducting said cooled effluent to a second reactor; and means within said second reactor for catalyzing the reduction of the nitric oxide in the cooled effluent with the ammonia therein to form a substantially nitric oxide free exhaust, said second reactor catalyzing means comprising a second catalyst which comprises an ammonium halide on a porous solid carrier at a temperature which falls within a range from about 170° C. to about 100° C.
Claim 5
Dependent Claim
249 words
Apparatus for reducing the nitric oxide content of a combusted gas stream, comprising: means for conducting a varying temperature combusted gas stream from a hydrocarbon burning engine, which gas stream comprises nitric oxide, to a first reactor; means for conducting ammonia to said first reactor; means within said first reactor for catalyzing the reduction of the nitric oxide with the ammonia to form a first reactor effluent, said first reactor catalyzing means comprising a first catalyst which comprises a porous inorganic oxide reduction catalyst for nitric oxide; means for determining the temperature of said first reactor effluent; means for conducting said first reactor effluent to exhaust when said temperature is above a threshold temperature in the range between about 220° C. to about 280° C.; means for conducting said first reactor effluent to cooling means only when said temperature is below said threshold temperature and thereat cooling said effluent with said cooling means to a temperature which falls within a range of about 170° C. to about 100° C. to form a cooled effluent; means for conducting said cooled effluent to a second reactor; and means within said second reactor for catalyzing the reduction of the nitric oxide in the cooled effluent with the ammonia therein to form a substantially nitric oxide free exhaust, said second reactor catalyzing means comprising a second catalyst which comprises an ammonium halide on a porous solid carrier at a temperature which falls within a range from about 170° C. to about 100° C.
Claim 6
Dependent Claim
79 words
An apparatus as in claim 3, including a valve which receives said first reactor effluent and control means receiving a signal representative of temperature of said first reactor effluent and shifting said valve to conduct said first reactor effluent to exhaust when said temperature is above a threshold temperature in the range between about 220° C. to about 280° C. and to conduct said first reactor effluent to said cooling means when said temperature is below said threshold temperature.
Claim 7
Dependent Claim
16 words
An apparatus as in claim 3 or 4 wherein said threshold temperature is about 260° C.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-05-21 | 1982-11-20 | 1983-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-05-21 | 1986-11-20 | 1987-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-05-21 | 1990-11-20 | 1991-05-22 | $7700.00 | Window Closed / Lapsed |