US4101634A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the simultaneous removal of nitrogen and sulfur oxides from a gas stream
Assignee: Shell USA Inc
•
Filing: 1977-02-04
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Granted: 1978-07-18
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Expires: 1997-02-04
Abstract
Abstract A process for the simultaneous removal of nitrogen oxides and sulfur oxides from a gas stream containing oxygen, in addition to nitrogen oxides and sulfur oxides, is disclosed.
Inventors
- 👤 Johannes E. G. Ploeg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:33
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/60; Y; Y02; Y02A; Y02A50/00; Y02A50/20
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
150 words
In a process for the simultaneous removal of nitrogen oxides and sulfur oxides from a gas stream containing oxygen, in addition to said oxides, in which process a metal-containing acceptor is used for the acceptance of sulfur oxides in the form of a metal sulfate and ammonia precursor is added to the gas stream for the reduction of the nitrogen oxides to nitrogen, and the metal sulfate-containing acceptor is regenerated at regular intervals by stopping the flow of the gas stream and introducing a reducing gas, the improvement comprising regenerating the acceptor by contacting the acceptor with the reducing gas in a flow counter-current to the direction in which the gas stream to be purified contacts the acceptor, the regeneration being terminated when at least part of the acceptor is still in the metal sulfate form, after which the flow of the oxygen-containing gas stream to be purified is continued.
Claim 2
Dependent Claim
150 words
In a process for the simultaneous removal of nitrogen oxides and sulfur oxides from a gas stream containing oxygen, in addition to said oxides, in which process a metal-containing acceptor is used for the acceptance of sulfur oxides in the form of a metal sulfate and ammonia precursor is added to the gas stream for the reduction of the nitrogen oxides to nitrogen, and the metal sulfate-containing acceptor is regenerated at regular intervals by stopping the flow of the gas stream and introducing a reducing gas, the improvement comprising regenerating the acceptor by contacting the acceptor with the reducing gas in a flow counter-current to the direction in which the gas stream to be purified contacts the acceptor, the regeneration being terminated when at least part of the acceptor is still in the metal sulfate form, after which the flow of the oxygen-containing gas stream to be purified is continued.
Claim 3
Dependent Claim
29 words
The process of claim 1, in which the regeneration is terminated when at least 10 percent by weight of the acceptor material present is in the metal sulfate form.
Claim 4
Dependent Claim
31 words
The process of claim 2, in which the regeneration is terminated when from 12 percent to 30 percent by weight of the acceptor material present is in the metal sulfate form.
Claim 5
Dependent Claim
11 words
The method of claim 3, wherein the metal-containing acceptor contains copper.
Claim 6
Dependent Claim
18 words
The process of claim 4, wherein the temperature employed during acceptance is from about 325° to 475° C.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-07-17 | 1982-01-16 | 1982-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-17 | 1986-01-16 | 1986-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-17 | 1990-01-16 | 1990-07-18 | $7700.00 | Window Closed / Lapsed |