US3784389A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and apparatus for burning cement including atomizing dryer in cyclone preheater bypass
Assignee: FLSmidth and Co AS
•
Filing: 1972-01-21
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Granted: 1974-01-08
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Expires: 1992-01-21
Abstract
Abstract In the manufacture of cement clinker from cement raw materials containing an undesirably high amount of alkalis, a rotary kiln having a preheater for the raw materials is employed. A portion of the effluent gases from the kiln is caused to bypass the preheater as a separate divisional flow. Water is atomized into this flow in such amounts that substantially all of the alkalis entrained therein in the form of solids, liquid or vapor are struck by the atomized fine drops of water. All of the water is vaporized in the hot flow of gas so that a substantial part of the alkalis is precipitated in the form of a fine dry powder, and the gas is simultaneously cooled.
Inventors
- 👤 N Hastrup
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 06:27
CPC Classifications
F; F27; F27B; F27B7/00; F27B7/20; F27B7/2016; F27B7/2025; C; C04; C04B; C04B7/00; C04B7/36; C04B7/60
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
59 words
The method according to claim 1, characterized in that the water atomized into the bypassing flow of effluent gas contains suspended fine particles of a carrier material to which a part of the alkalis clings at the vaporization of the water so that alkali-enriched carrier material will be incorporated in the fine dry powder precipitated from the gas flow.
Claim 2
Dependent Claim
49 words
The method according to claim 2, characterized in that the carrier material is constituted of a pulverised fertilizer the fertilizing effect of which is improved by an addition of alkalis, by which the fine dry powder precipitated from the gas flow becomes a fertilizer powder thus enriched in alkalis.
Claim 3
Dependent Claim
30 words
The method according to claim 2, characterized in that the carrier material is constituted by a certain fraction of the fine dry alkali powder previously precipitated from the gas flow.
Claim 4
Dependent Claim
73 words
The method according to claim 2, characterized in that the carrier material is a readily filtrable substance which will thus constitute a part of the fine dry alkali-containing powder precipitated from the gas flow in which the powder is suspended in water, the suspension being subsequently filtered so as to produce a cake of slurry containing the carrier material and impurities from the effluent gases, and water in which the alkalis are dissolved.
Claim 5
Dependent Claim
14 words
The method according to claim 5, in which the readily filtrable substance is sand.
Claim 6
Dependent Claim
15 words
The method according to claim 5, in which the filtrable substance is cement raw materials.
Claim 7
Dependent Claim
26 words
The method according to claim 1 in which the bypassing gas flow constitutes from about 2 percent to about 12 percent of the undivided gas flow.
Claim 8
Dependent Claim
18 words
The method according to claim 1 in which the gas flow bypassing the raw materials flow is intermittent.
Claim 9
Dependent Claim
49 words
The method according to claim 1 in which the amount of gas bypassing the raw materials preheater is varied automatically according to the alkali content of the gases leaving the rotary kiln so that the higher the alkali content of the gases the greater the amount of gas bypassed.
Claim 10
Dependent Claim
34 words
The method according to claim 1 in which the amount of water atomized into the bypassing flow of exit gas is varied according to the amount of exit gas bypassing the raw materials preheater.
Claim 11
Dependent Claim
40 words
The method according to claim 1 in which the amount of water atomized into the bypassing flow of exit gas is varied according to the temperature of said bypassing flow after it has given off heat during said spray drying.
Claim 12
Dependent Claim
68 words
A rotary kiln plant comprising a rotary kiln, a raw materials suspension preheater coupled thereto, an effluent gas bypass pipe bypassing the suspension preheater, a spray dryer in the bypass pipe, means for introducing water into the spray dryer in the form of very fine drops, and means for collecting and removing the greater part of the resulting precipitated alkalis in the form of a fine dry powder.
Claim 13
Dependent Claim
27 words
A rotary kiln plant according to claim 13 which further comprises an electrostatic dust precipitator arranged to receive the flow from the suspension preheater for raw materials.
Claim 14
Dependent Claim
33 words
A rotary kiln plant according to claim 14, in which the effluent gas outlet pipe of the suspension preheater and the effluent gas bypass pipe are both connected to the electrostatic dust precipitator.
Claim 15
Dependent Claim
50 words
A rotary kiln plant according to claim 13 which includes a turbomixing apparatus for suspending solids in a liquid, means for feeding carrier material and water to the turbomixing apparatus and means for conveying the water with the carrier material suspended therein from the turbomixing apparatus to the spray dryer.
Claim 16
Dependent Claim
59 words
A rotary kiln according to claim 16, in which the means for collecting and removing precipitated alkalis in the form of a fine dry powder include means for dividing the flow of said powder into two divisional flows, preferably in amounts regulable in relation to each other, and means for feeding one of the flows to the turbomixing apparatus.
Claim 17
Dependent Claim
35 words
A rotary kiln plant according to claim 16, which includes a filtering device, means for removing from the turbomixing apparatus the suspension therein and means for carrying away the filter water and the filter cake.
Claim 18
Dependent Claim
22 words
A rotary kiln plant according to claim 13 including means for feeding water, with suspended carrier material therein, to the spray dryer.
Claim 19
Dependent Claim
39 words
A rotary kiln plant according to claim 17, including means for causing the amount of effluent gas passing through the bypass pipe to be regulated automatically according to the alkali content in the exit gases leaving the rotary kiln.
Claim 20
Dependent Claim
34 words
A rotary kiln plant according to claim 19 which further comprises means for regulating automatically the supply of liquid to the spray dryer according to the amount of effluent gas bypassing the suspension preheater.
Claim 21
Dependent Claim
40 words
A rotary kiln plant according to claim 19 which includes in addition means for regulating automatically the supply of liquid to the spray dryer according to the temperature of the effluent gases after they have passed through the spray dryer.
References Cited (Backward Citations)
US3512340A
Cited
US3365521A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-07 | 1977-07-09 | 1978-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-07 | 1981-07-09 | 1982-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-07 | 1985-07-09 | 1986-01-08 | $7700.00 | Window Closed / Lapsed |