Patent US4782772A successfully refreshed from Google Patents.
US4782772A
Expired / Lapsed
US
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Method of directly removing sulfur, with flue dust being returned
Assignee: Hitachi Zosen Inova Steinmueller GmbH
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Filing: 1987-10-14
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Granted: 1988-11-08
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Expires: 2007-10-14
Abstract
Abstract A method of purifying flue gas from the firing equipment of a combustion unit, especially fuel gas from fitting equipment to which low-ash flue is supplied, or from a grating firing having a high degree of ash removal, with the flue gas containing noxious compounds. A finely divided or pulverous basic additive is used on which the noxious compounds produced during firing are adsorbed. Flue dust, especially flue dust/additive mixture, that is carried along in the flue gas is separated from the latter, with at least a portion of the separated-off flue dust being hydrated and sifted, whereby subsequently at least a portion of the dry, hydrated flue dust is returned to the flue gas purification process. Non-pulverized flue dust is homogenously mixed with finely sprayed water to effect the hydration. The return of flue dust to the flue gas purification process is undertaken by returning at least a portion of dry, thus-hydrated flue dust to the firing equipment of the combustion unit.
Inventors
- 👤 Yaqub Chughtai
- 👤 Volkmar Sitte
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:13
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/501; B01D53/68; B03; B03B; B03B9/00; B03B9/04; F; F23; F23J; F23J3/00; F23J3/06; F23J7/00
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
173 words
In a method of purifying flue gas that comes from the firing equipment of a combustion unit, especially flue gas from firing equipment to which low-ash fuel is supplied, or from a grating firing having a high degree of ash removal, with said flue gas containing noxious compounds, including the step of using a pulverous basic additive on which said noxious compounds produced during firing are adsorbed, whereby flue dust, especially flue dust/additive mixture, that is carried along in said flue gas is separated from the latter, with at least a portion of the separated-off flue dust being hydrated and sifted, whereby subsequently at least a portion of the dry, hydrated flue dust is returned to the flue gas purification process, the improvement comprising the steps of: homogeneously mixing non-pulverized, separated-off flue dust with finely sprayed water to effect said hydration; and undertaking said return of flue dust to the flue gas purification process by returning at least a portion of dry, thus-hydrated flue dust to said firing equipment of said combustion unit.
Claim 2
Dependent Claim
173 words
In a method of purifying flue gas that comes from the firing equipment of a combustion unit, especially flue gas from firing equipment to which low-ash fuel is supplied, or from a grating firing having a high degree of ash removal, with said flue gas containing noxious compounds, including the step of using a pulverous basic additive on which said noxious compounds produced during firing are adsorbed, whereby flue dust, especially flue dust/additive mixture, that is carried along in said flue gas is separated from the latter, with at least a portion of the separated-off flue dust being hydrated and sifted, whereby subsequently at least a portion of the dry, hydrated flue dust is returned to the flue gas purification process, the improvement comprising the steps of: homogeneously mixing non-pulverized, separated-off flue dust with finely sprayed water to effect said hydration; and undertaking said return of flue dust to the flue gas purification process by returning at least a portion of dry, thus-hydrated flue dust to said firing equipment of said combustion unit.
Claim 3
Dependent Claim
27 words
A method according to claim 1, which includes the step of sifting said portion of flue dust that is to be returned prior to said hydration step.
Claim 4
Dependent Claim
27 words
A method according to claim 1, which includes the step of sifting said portion of flue dust that is to be returned subsequent to said hydration step.
Claim 5
Dependent Claim
30 words
A method according to claim 1, which includes the step of sifting said portion of flue dust that is to be returned prior to and subsequent to said hydration step.
Claim 6
Dependent Claim
28 words
A method according to claim 1, which includes the step of providing, as said basic, pulverous additive, one of the group consisting of calcium hydroxide and calcium carbonate.
Claim 7
Dependent Claim
30 words
A method according to claim 1, which includes the step of mixing said returned portion of flue dust to fresh additive that is to be supplied to said firing equipment.
Claim 8
Dependent Claim
22 words
A method according to claim 1, which includes the step of undertaking said hydration with a greater than stoichiometric quantity of water.
Claim 9
Dependent Claim
23 words
A method according to claim 7, which includes the step, after said hydration, of drying said flue dust to remove excess water therefrom.
Claim 10
Dependent Claim
17 words
A method according to claim 8, which includes the step of effecting said drying via autothermic drying.
Claim 11
Dependent Claim
184 words
In a method of purifying flue gas that comes from the firing equipment of a combustion unit, especially flue gas from firing equipment to which low-ash fuel is supplied, or from a grating firing having a high degree of ash removal, with said flue gas containing noxious compounds, including the step of using a pulverous basic additive on which said noxious compounds produced during firing are adsorbed, whereby flue dust, especially flue dust/additive mixture, that is carried along in said flue gas is separated from the latter, with at least a portion of the separated-off flue dust being hydrated and sifted, whereby subsequently at least a portion of the dry, hydrated flue dust is returned to the flue gas purification process, the improvement comprising the steps of: homogeneously mixing non-pulverized, separated-off flue dust with finely sprayed water to effect said hydration; undertaking said return of flue dust to the flue gas purification process by returning at least a portion of dry, thus-hydrated flue dust to said firing equipment of said combination unit; and undertaking said hydration with a greater than stoichiometric quantity of water.
Claim 12
Dependent Claim
184 words
In a method of purifying flue gas that comes from the firing equipment of a combustion unit, especially flue gas from firing equipment to which low-ash fuel is supplied, or from a grating firing having a high degree of ash removal, with said flue gas containing noxious compounds, including the step of using a pulverous basic additive on which said noxious compounds produced during firing are adsorbed, whereby flue dust, especially flue dust/additive mixture, that is carried along in said flue gas is separated from the latter, with at least a portion of the separated-off flue dust being hydrated and sifted, whereby subsequently at least a portion of the dry, hydrated flue dust is returned to the flue gas purification process, the improvement comprising the steps of: homogeneously mixing non-pulverized, separated-off flue dust with finely sprayed water to effect said hydration; undertaking said return of flue dust to the flue gas purification process by returning at least a portion of dry, thus-hydrated flue dust to said firing equipment of said combination unit; and undertaking said hydration with a greater than stoichiometric quantity of water.
Claim 13
Dependent Claim
27 words
A method according to claim 10, which includes the step of sifting said portion of flue dust that is to be returned subsequent to said hydration step.
Claim 14
Dependent Claim
30 words
A method according to claim 10, which includes the step of sifting said portion of flue dust that is to be returned prior to and subsequent to said hydration step.
Claim 15
Dependent Claim
23 words
A method according to claim 10, which includes the step, after said hydration, of drying said flue dust to remove excess water therefrom.
Claim 16
Dependent Claim
17 words
A method according to claim 13, which includes the step of effecting said drying via autothermic drying.
References Cited (Backward Citations)
US4397742A
Cited
US4309393A
Cited
US4387078A
Cited
US4519995A
Cited
US4550049A
Cited
US4645654A
Cited
DE3428502A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-11-08 | 1992-05-09 | 1992-11-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-08 | 1996-05-09 | 1996-11-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-08 | 2000-05-09 | 2000-11-08 | $7700.00 | Window Closed / Lapsed |