US4744967A
Expired / Lapsed
US
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Process for the purification of exhaust gases containing oxides of nitrogen and sulfur
Assignee: Evonik Operations GmbH
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Filing: 1987-01-20
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Granted: 1988-05-17
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Expires: 2007-01-20
Abstract
Abstract A process is described for the purification of exhaust gases containing oxides of nitrogen and sulfur obtained from combustion installations and industrial production processes by selective catalytic reduction of the nitric oxides with ammonia, subsequent catalytic oxidation of sulfur dioxide with oxygen and conversion into sulfuric acid of the sulfur trioxide obtained.
Inventors
- 👤 Reinhold Brand
- 👤 Bernd Engler
- 👤 Peter Kleine-Moellhoff
- 👤 Edgar Koberstein
- 👤 Herbert Voelker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 05:23
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8637; F; F23; F23J; F23J15/00; F23J15/006; F23J2215/00; F23J2215/20; F23J2217/00; F23J2217/10; F23J2217/102; F23J2219/00; F23J2219/10; F23J2219/40
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
142 words
A process for the purification of exhaust gas containing oxides of nitrogen and sulfur obtained from combustion installations and industrial production processes comprising selectively catalytically reducing the oxides of nitrogen with a sufficient amount of ammonia for the reduction of oxides of nitrogen in the exhaust gas in the presence of a reduction catalyst at a temperature in the range of 250°-550° C., and subsequently oxidizing sulfur dioxide with oxygen in the presence of a catalyst therefor at a temperature in the range of 250°-550° C. to obtain sulfur trioxide, cooling the sulfur trioxide to a temperature of from 20°-160° C., and converting the sulfur trioxide obtained into sulfuric acid, wherein the reduction and oxidation are carried out in a single reaction zone, the first section of which contains said reduction catalyst and the second section of which contains said oxidation catalyst.
Claim 2
Dependent Claim
142 words
A process for the purification of exhaust gas containing oxides of nitrogen and sulfur obtained from combustion installations and industrial production processes comprising selectively catalytically reducing the oxides of nitrogen with a sufficient amount of ammonia for the reduction of oxides of nitrogen in the exhaust gas in the presence of a reduction catalyst at a temperature in the range of 250°-550° C., and subsequently oxidizing sulfur dioxide with oxygen in the presence of a catalyst therefor at a temperature in the range of 250°-550° C. to obtain sulfur trioxide, cooling the sulfur trioxide to a temperature of from 20°-160° C., and converting the sulfur trioxide obtained into sulfuric acid, wherein the reduction and oxidation are carried out in a single reaction zone, the first section of which contains said reduction catalyst and the second section of which contains said oxidation catalyst.
Claim 3
Dependent Claim
17 words
The process according to claim 1, further comprising initially treating said exhaust gas to remove dust therefrom.
Claim 4
Dependent Claim
20 words
The process according to claim 1, further comprising treating the exhaust gas for removal of dust after an intermediate cooling.
Claim 5
Dependent Claim
21 words
The process according to claim 3, wherein the removal of dust treatment is carried out prior to conversion to sulfuric acid.
Claim 6
Dependent Claim
22 words
The process according to claim 1, wherein the reduction catalyst for the nitric oxide reduction is a honeycomb or in particulate form.
Claim 7
Dependent Claim
17 words
The process according to claim 1, wherein the oxidation catalyst is a honeycomb or in particulate form.
Claim 8
Dependent Claim
16 words
The process according to claim 1, wherein the reduction catalyst consists of a catalytically active mass.
Claim 9
Dependent Claim
23 words
The process according to claim 1, wherein the reduction catalyst comprises a catalytically active substance deposited on an inert, ceramic or metallic body.
Claim 10
Dependent Claim
20 words
The process according to claim 8, wherein said inert body is additionally coated with a surface area enlarging oxide layer.
Claim 11
Dependent Claim
15 words
The process according to claim 1, wherein the oxidation catalyst consists of catalytically active mass.
Claim 12
Dependent Claim
23 words
The process according to claim 1, wherein the oxidation catalyst comprises a catalytically active substance deposited on an inert, ceramic or metallic body.
Claim 13
Dependent Claim
20 words
The process according to claim 11, wherein said inert body is additionally coated with a surface area enlarging oxide layer.
Claim 14
Dependent Claim
15 words
The process according to claim 1, wherein the temperature range for reducing is 350°-450° C.
Claim 15
Dependent Claim
13 words
The process according to claim 13, wherein the temperature range is 380°-420° C.
Claim 16
Dependent Claim
15 words
The process according to claim 1, wherein the temperature range of oxidation is 350°-450° C.
Claim 17
Dependent Claim
13 words
The process according to claim 15, wherein the temperature range is 380°-420° C.
Claim 18
Dependent Claim
14 words
The process according to claim 1, wherein the temperature of cooling is 70°-150° C
Claim 19
Dependent Claim
14 words
The process according to claim 1, wherein the temperature of cooling is 110°-140° C.
Claim 20
Dependent Claim
29 words
The process according to claim 1, wherein the sulfur trioxide is treated by hydration carried out in a one- or multistep scrubber with 70-85%, by weight of sulfuric ,acid.
Claim 21
Dependent Claim
16 words
The process according to claim 19, wherein the process is carried out with 75-80% sulfuric acid.
Claim 22
Dependent Claim
22 words
The process according to claim 19, wherein the hydration of the sulfur trioxide is carried out at a temperature of 40°-130° C.
Claim 23
Dependent Claim
10 words
The process according to claim 21, wherein the temperature95°-125° C.
Claim 24
Dependent Claim
12 words
The process according to claim 21, wherein the temperature is 100°-115° C.
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) | 1991-05-17 | 1991-11-16 | 1992-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-17 | 1995-11-16 | 1996-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-17 | 1999-11-16 | 2000-05-17 | $7700.00 | Window Closed / Lapsed |