US4119703A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for removal of nitrogen oxides from waste gas
Assignee: JGC Corp
•
Filing: 1977-03-14
•
Granted: 1978-10-10
•
Expires: 1997-03-14
Abstract
Abstract A process for the removal of nitrogen oxides from a waste gas containing said nitrogen oxides in conjunction with sulfur oxides is disclosed, which process comprises allowing said waste gas to come into contact with ammonia as the reducing agent at temperature in the range of from 250° to 550° C in the presence of a catalyst wherein an active component containing iron or copper as the active metal is supported on a silica-alumina type carrier containing not less than 60% by weight of silica and the pore volume occupied by the pores measuring 150 A or over in diameter exceeds 0.15 cc/g, for thereby causing selective catalytic reduction of said nitrogen oxides.
Inventors
- 👤 Fusao Nishida
- 👤 Tomiaki Yamada
- 👤 Noriyuki Suzuki
- 👤 Takehiko Takeda
- 👤 Tsutomu Yanagihara
- 👤 Katsuhiko Adachi
- 👤 Tadashi Asanabe
- 👤 Katuaki Ohsato
- 👤 Kintaro Tsuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:05
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; B01D53/8628; B01J; B01J23/00; B01J23/70; B01J21/00; B01J21/12; B01J27/00; B01J27/02; B01J27/053; B01J27/055; B01J35/00; B01J35/60
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
162 words
A process for the reductive removal of nitrogen oxides from waste gas containing said oxides in conjunction with sulfur oxides which cmprises contacting said waste gas having a GHSV of from 1000 to 50,000 HR -1 with ammonia at a termperature of from 250° to 500° C. in the presence of a catalyst, the active component of which is selected from the group consisting of oxides and sulfates of iron and copper and mixtures thereof, the catalyst being supported on a silica-alumina type carrier containing at least 60% by weight of silica, the amount of the active component being from 0.5 to 20% by weight based on the weight of the carrier, the pore volume of the catalyst occupied by pores measuring at least 150 A in diameter being from 0.15 cc/g to 0.5 cc/g, the total pore volume of the catalyst being at least 0.5 cc/g and the specific surface area of the catalyst being at least 50 m 2 /g.
Claim 2
Dependent Claim
162 words
A process for the reductive removal of nitrogen oxides from waste gas containing said oxides in conjunction with sulfur oxides which cmprises contacting said waste gas having a GHSV of from 1000 to 50,000 HR -1 with ammonia at a termperature of from 250° to 500° C. in the presence of a catalyst, the active component of which is selected from the group consisting of oxides and sulfates of iron and copper and mixtures thereof, the catalyst being supported on a silica-alumina type carrier containing at least 60% by weight of silica, the amount of the active component being from 0.5 to 20% by weight based on the weight of the carrier, the pore volume of the catalyst occupied by pores measuring at least 150 A in diameter being from 0.15 cc/g to 0.5 cc/g, the total pore volume of the catalyst being at least 0.5 cc/g and the specific surface area of the catalyst being at least 50 m 2 /g.
Claim 3
Dependent Claim
27 words
The process according to claim 1, wherein the amount of the active component is from 1 to 10% by weight of active metal based on the carrier.
Claim 4
Dependent Claim
19 words
The process according to claim 1, wherein the silica-alumina carrier contains from 60 to 99% by weight of silica.
Claim 5
Dependent Claim
19 words
The process according to claim 3, wherein the silica-alumina carrier contains from 70 to 90% by weight of silica.
Claim 6
Dependent Claim
30 words
The process according to claim 1, wherein the volume of ammonia supplied as the reducing agent is such that the NH 3 NO molar ratio is from 0.8 to 1.5.
Claim 7
Dependent Claim
19 words
The process according to claim 1, wherein the molar ratio of NH 3 NO is from 1.0 to 1.2.
References Cited (Backward Citations)
US3008796A
Cited
US3279884A
Cited
US3705231A
Cited
GB1355214A
Cited
BE804316A
Cited
JPS4948590A
Cited
US3895094A
Cited
US4010328A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-10-09 | 1982-04-10 | 1982-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-09 | 1986-04-10 | 1986-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-09 | 1990-04-10 | 1990-10-10 | $7700.00 | Window Closed / Lapsed |