US4307068A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for treating an exhaust gas
Assignee: Mitsubishi Heavy Industries Ltd
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Filing: 1980-08-15
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Granted: 1981-12-22
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Expires: 2000-08-15
Abstract
Abstract A method for treating an exhaust gas containing nitrogen oxides, oxygen and soot, in which the nitrogen oxides are selectively reduced into nitrogen by adding ammonia to the exhaust gas as a reducing agent under existence of a catalyzer, is improved in that the nitrogen oxide is removed by introducing the exhaust gas into a denitration reactor in which a plurality of planar catalyzer packs or catalyzer packs having gas passage holes are arrayed in parallel to a gas flow and a linear velocity of the gas through the reactor is selected at 4-15 m/s. In one preferred mode of the method, soot having a relatively large particle diameter is preliminarily removed by a dust remover disposed upstream of the reactor, while most of the remaining soot is removed by a high performance dust collector disposed downstream of the reactor. Denitration reactor structures suitable for the improved method for treatment are also disclosed herein.
Inventors
- 👤 Kazuhiro Matsumoto
- 👤 Toru Seto
- 👤 Takeji Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:33
CPC Classifications
F; F01; F01N; F01N3/00; F01N3/08; F01N3/10; F01N3/24; F01N3/28; F01N3/2803; F01N3/2825; F01N3/2828; B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; B01D53/8631; F01N3/18; F01N3/20; F01N3/206; F01N2330/00; F01N2330/06; F01N2610/00; F01N2610/02
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
163 words
In a method for treating a coal boiler exhaust gas containing nitrogen oxides, oxygen and soot, in which the nitrogen oxides are selectively reduced into nitrogen by adding ammonia to the exhaust gas as a reducing agent under the existence of a catalyzer; the improvement which comprises first removing soot having a particle size of 50μ in diameter and larger by passing coal boiler exhaust gas through an axial-flow cyclone dust remover, introducing the gas into the denitration reactor to remove the nitrogen oxides by passing the gas through parallel passage ways through a denitration reactor at a linear velocity of 4-15 m/s, said denitration reactor being made up of a plurality of planar catalyzer packs or catalyzer packs having gas passage holes arranged in parallel to the gas flow and then removing the remaining soot by passing the gas through a dust collector to remove dust or soot of a particle size smaller than 50μ at the downstream of said denitration reactor.
Claim 2
Dependent Claim
163 words
In a method for treating a coal boiler exhaust gas containing nitrogen oxides, oxygen and soot, in which the nitrogen oxides are selectively reduced into nitrogen by adding ammonia to the exhaust gas as a reducing agent under the existence of a catalyzer; the improvement which comprises first removing soot having a particle size of 50μ in diameter and larger by passing coal boiler exhaust gas through an axial-flow cyclone dust remover, introducing the gas into the denitration reactor to remove the nitrogen oxides by passing the gas through parallel passage ways through a denitration reactor at a linear velocity of 4-15 m/s, said denitration reactor being made up of a plurality of planar catalyzer packs or catalyzer packs having gas passage holes arranged in parallel to the gas flow and then removing the remaining soot by passing the gas through a dust collector to remove dust or soot of a particle size smaller than 50μ at the downstream of said denitration reactor.
Claim 3
Dependent Claim
48 words
A method according to claim 1 in which said catalyzer packs are made of a hydraulic material composed primarily of a molded and hardened material of a hydraulic granular composed principally of a mixture of gypsum and calcium content containing the catalyst intimately mixed with the hydraulic material.
Claim 4
Dependent Claim
27 words
A method according to claim 2 wherein the hydraulic granular material used to form the catalyst planar packs are made of a mixture of gypsum and cement.
Claim 5
Dependent Claim
39 words
A method according to claim 2 in which the active catalyst intimately mixed with the hydraulic material is an oxide or a sulfate of a metal selected from the group consisting of vanadium, molybdenum, tungsten, iron, chromium and copper.
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) | 1984-12-21 | 1985-06-22 | 1985-12-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-21 | 1989-06-22 | 1989-12-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-21 | 1993-06-22 | 1993-12-22 | $7700.00 | Window Closed / Lapsed |