Patent US3993731A successfully refreshed from Google Patents.
US3993731A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Selective removal of nitrogen oxides from waste gas
Assignee: JGC Corp
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Filing: 1975-06-09
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Granted: 1976-11-23
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Expires: 1995-06-09
Abstract
Abstract A process for the removal of nitrogen oxides from a waste gas containing said oxides in conjunction with sulfur oxides which comprises contacting said waste gas with ammonia as a reducing agent at temperatures of from 250° to 550° C in the presence of a catalyst wherein an active component containing iron or copper as the active metal and a sulfate of aluminum are supported on a silica carrier.
Inventors
- 👤 Kiyoshi Morikawa
- 👤 Fusao Nishida
- 👤 Tomiaki Yamada
- 👤 Noriyuki Suzuki
- 👤 Takehiko Takeda
- 👤 Tsutomu Yanagihara
- 👤 Katshiko Adachi
- 👤 Tadashi Asanabe
- 👤 Katuaki Ohsato
- 👤 Kintaro Tsuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:44
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; B01D53/8628; B01J; B01J23/00; B01J23/70; B01J27/00; B01J27/02; B01J27/053
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
104 words
A process for the removal of nitrogen oxides from a waste gas containing said nitrogen oxides in conjunction with sulfur oxides, which process is characterized by contacting said waste gas with ammonia as the reducing agent at a temperature from 250° to 550° C in the presence of a catalyst having supported on silica an active component containing iron or copper as the active metal and an aluminum sulfate, for thereby causing selective catalytic reduction of said nitrogen oxides the specific surface area of the carrier being not less than 50 m 2 /g and the pore volume being from 0.2 to 1.5 cc/g.
Claim 2
Dependent Claim
104 words
A process for the removal of nitrogen oxides from a waste gas containing said nitrogen oxides in conjunction with sulfur oxides, which process is characterized by contacting said waste gas with ammonia as the reducing agent at a temperature from 250° to 550° C in the presence of a catalyst having supported on silica an active component containing iron or copper as the active metal and an aluminum sulfate, for thereby causing selective catalytic reduction of said nitrogen oxides the specific surface area of the carrier being not less than 50 m 2 /g and the pore volume being from 0.2 to 1.5 cc/g.
Claim 3
Dependent Claim
32 words
The process according to claim 1, wherein the active component containing iron or copper is selected from the group consisting of oxides of iron and copper and sulfates of iron and copper.
Claim 4
Dependent Claim
29 words
The process according to claim 1, wherein the amount of the active component is from 0.5 to 20% by weight as active metal based on the weight of carrier.
Claim 5
Dependent Claim
29 words
The process according to claim 3, wherein the amount of the active component is from 1 to 10% by weight as active metal based on the weight of carrier.
Claim 6
Dependent Claim
27 words
The process according to claim 1, wherein the amount of aluminum sulfate is from 0.1 to 5% by weight as aluminum based on the weight of carrier.
Claim 7
Dependent Claim
27 words
The process according to claim 5, wherein the amount of aluminum sulfate is from 0.5 to 3% by weight as aluminum based on the weight of carrier.
Claim 8
Dependent Claim
27 words
The process according to claim 1, wherein the ratio of aluminum sulfate to the active component is from 0.05 to 0.5 in terms of metal weight ratio.
Claim 9
Dependent Claim
21 words
The process according to claim 1, wherein the gas hourly space velocity is from 1000 to 50000 HR - 1 .
Claim 10
Dependent Claim
31 words
The process according to claim 1, wherein the amount of ammonia supplied as the reducing agent is such that the molar ratio of NH 3 /NO is from 0.8 to 1.5.
Claim 11
Dependent Claim
19 words
The process according to claim 9, wherein the molar ratio of NH 3 /NO is from 1.0 to 1.2.
Claim 12
Dependent Claim
118 words
A process for the removal of nitrogen oxides from a waste gas containing said nitrogen oxides together with sulfur oxides, which process is characterized by contacting said waste gas with ammonia as the reducing agent at a temperature from 250° to 550° C in the presence of a catalyst using as the carrier, silica having not less than 50m 2 /g of specific surface area and from 0.2 to 1.5 cc/g of pore volume, and having supported on said carrier an active component containing from 0.5 to 20% by weight, based on said carrier, of iron or copper as the active metal and aluminum sulfate containing from 0.1 to 5% by weight, based on the carrier, of aluminum.
Claim 13
Dependent Claim
118 words
A process for the removal of nitrogen oxides from a waste gas containing said nitrogen oxides together with sulfur oxides, which process is characterized by contacting said waste gas with ammonia as the reducing agent at a temperature from 250° to 550° C in the presence of a catalyst using as the carrier, silica having not less than 50m 2 /g of specific surface area and from 0.2 to 1.5 cc/g of pore volume, and having supported on said carrier an active component containing from 0.5 to 20% by weight, based on said carrier, of iron or copper as the active metal and aluminum sulfate containing from 0.1 to 5% by weight, based on the carrier, of aluminum.
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) | 1979-11-23 | 1980-05-24 | 1980-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-23 | 1984-05-24 | 1984-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-23 | 1988-05-24 | 1988-11-23 | $7700.00 | Window Closed / Lapsed |