US3867507A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for removing the oxides of nitrogen as air contaminants
Assignee: ExxonMobil Technology and Engineering Co
•
Filing: 1973-03-16
•
Granted: 1975-02-18
•
Expires: 1993-03-16
Abstract
Abstract A method for treating a stream of combustion effluents, containing NOx and other contaminants, said method comprising the steps of first contacting the stream with a sufficient amount of hydrocarbon in the presence of oxygen at a temperature ranging from 400 to 2,700*C. for sufficient time to substantially reduce the NOx to molecular nitrogen; contacting the reduced stream with sufficient oxygen at a temperature ranging from 400 to 2,700*C. for a time sufficient to substantially oxidize all other contaminants to an oxidized state. It has been found that this reduction can also be carried out in an intermittent manner in which the reducing hydrocarbon-oxygen mixture can be shut off for hours at a time with continuing NO- removal (the self-contained reductant mode).
Inventors
- 👤 Albert L Myerson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:40
CPC Classifications
F; F01; F01N; F01N3/00; F01N3/08; F01N3/10; F01N3/24; F01N3/26; B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/54; B01D53/56; F01N3/36
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
111 words
A THERMAL METHOD FOR TREATING A STREAM OF COMBUSTION EFFLUENTS ISSUING FROM EITHER A MOBILE OR STATIONARY SOURCE CONTAINING NOX AND OTHER CONTAMINANTS, SAID METHOD COMPRISING THE STEP OF INJECTING INTO SAID STREAM A HYDROCARBON COMPOUND AND OXYGEN IN SUFFICIENT AMOUNTS TO MAINTAIN THE RATIO OF (C) TO (NOX) NO GREATER THAN 32 TO 1 AND THE RATIO OF OXYGEN MOLECULES TO CARBON ATOMS NO GREATER THAN 2.5 TO 1, SAID HYDROCARBON COMPOUND BEING ONE SELECTED FROM THE GROUP CONSISTING OF HYDROCARBONS, OXYGEN-CONTAINING HYDROCARBONS, NITROGEN-CONTAINING HYDROCARBONS, HALOGENCONTAINING HYDROCARBONS, AND SULFUR-CONTIANING HYDROCARBONS AT A TEMPERATURE RANGING FROM 400* TO 2,700*C FOR A SUFFICIENT TIME TO SUBSTANIALLY REDUCE THE NOX TO MOLECULAR NITROGEN.
Claim 2
Dependent Claim
111 words
A THERMAL METHOD FOR TREATING A STREAM OF COMBUSTION EFFLUENTS ISSUING FROM EITHER A MOBILE OR STATIONARY SOURCE CONTAINING NOX AND OTHER CONTAMINANTS, SAID METHOD COMPRISING THE STEP OF INJECTING INTO SAID STREAM A HYDROCARBON COMPOUND AND OXYGEN IN SUFFICIENT AMOUNTS TO MAINTAIN THE RATIO OF (C) TO (NOX) NO GREATER THAN 32 TO 1 AND THE RATIO OF OXYGEN MOLECULES TO CARBON ATOMS NO GREATER THAN 2.5 TO 1, SAID HYDROCARBON COMPOUND BEING ONE SELECTED FROM THE GROUP CONSISTING OF HYDROCARBONS, OXYGEN-CONTAINING HYDROCARBONS, NITROGEN-CONTAINING HYDROCARBONS, HALOGENCONTAINING HYDROCARBONS, AND SULFUR-CONTIANING HYDROCARBONS AT A TEMPERATURE RANGING FROM 400* TO 2,700*C FOR A SUFFICIENT TIME TO SUBSTANIALLY REDUCE THE NOX TO MOLECULAR NITROGEN.
Claim 3
Dependent Claim
117 words
A thermal method for treating the exhaust gas of internal combustion engines containing CO, NOx and other contaminants, said method comprising the steps of injecting into the exhaust gas, gasoline and air in sufficient amounts to maintain the ratio of (C) to (NOx) no greater than 32 to 1 and the ratio of oxygen to carbon atoms in a range no greater than 2.5 to 1 at a temperature ranging from 700*C to 1,450*C for a sufficient time to reduce the NOx to molecular nitrogen and then contacting the reduced exhaust gas with a sufficient amount of oxygen to oxidize the excess hydrocarbon, CO and other oxidizable contaminants to less objectionable products upon emission into the atmosphere.
Claim 4
Dependent Claim
117 words
A thermal method for treating the exhaust gas of internal combustion engines containing CO, NOx and other contaminants, said method comprising the steps of injecting into the exhaust gas, gasoline and air in sufficient amounts to maintain the ratio of (C) to (NOx) no greater than 32 to 1 and the ratio of oxygen to carbon atoms in a range no greater than 2.5 to 1 at a temperature ranging from 700*C to 1,450*C for a sufficient time to reduce the NOx to molecular nitrogen and then contacting the reduced exhaust gas with a sufficient amount of oxygen to oxidize the excess hydrocarbon, CO and other oxidizable contaminants to less objectionable products upon emission into the atmosphere.
Claim 5
Dependent Claim
16 words
A method according to claim 2 wherein the residence time ranges from 25 to 250 milliseconds.
Claim 6
Dependent Claim
14 words
A method according to claim 1 wherein said hydrocarbon is a commercial grade gasoline.
Claim 7
Dependent Claim
21 words
A method according to claim 1 further including the step of intermittently contacting the effluent stream with said hydrocarbon and oxygen.
Claim 8
Dependent Claim
113 words
A thermal method for treating the effluent gas from a stationary source containing CO, NOx and other contaminants, said method comprising the steps of injecting into said effluent a hydrocarbon and air, in sufficient amounts to maintain the ratio of (C) to (NOx) no greater than 32 to 1 and the ratio of oxygen molecules to carbon atoms no greater than 2.5 to 1, at a temperature ranging from 700*C to 2200*C for a sufficient time to reduce the NOx to molecular nitrogen; contacting the reduced effluent gas with a sufficient amount of oxygen to oxidize the excess hydrocarbon, CO and other oxidizable contaminants to less objectionable products upon admission to the atmosphere.
Claim 9
Dependent Claim
113 words
A thermal method for treating the effluent gas from a stationary source containing CO, NOx and other contaminants, said method comprising the steps of injecting into said effluent a hydrocarbon and air, in sufficient amounts to maintain the ratio of (C) to (NOx) no greater than 32 to 1 and the ratio of oxygen molecules to carbon atoms no greater than 2.5 to 1, at a temperature ranging from 700*C to 2200*C for a sufficient time to reduce the NOx to molecular nitrogen; contacting the reduced effluent gas with a sufficient amount of oxygen to oxidize the excess hydrocarbon, CO and other oxidizable contaminants to less objectionable products upon admission to the atmosphere.
Claim 10
Dependent Claim
19 words
A method according to claim 6 wherein the ratio of O2/C in the second contacting is greater than 1.
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) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |