US4308808A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coal burning method to reduce particulate and sulfur emissions
Assignee: Alcoa Corp
•
Filing: 1980-09-02
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Granted: 1982-01-05
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Expires: 2000-09-02
Abstract
Abstract A method is disclosed for burning a pulverized carbonaceous material containing sulfur and ash. According to this method, a slurry is formed containing the carbonaceous material, water, a reagent adapted to react during combustion with the sulfur in the material and a cementing agent adapted to reduce particulate emissions during combustion. The slurry is burned in a first stage with less than 100% theoretical air and preferably at a temperature below about 1100° C. The products of combustion from the first stage are removed to a second stage and burned with additional air.
Inventors
- 👤 Melvin H. Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:47
CPC Classifications
F; F23; F23C; F23C6/00; F23C6/04; F23K; F23K1/00; F23K1/02; Y; Y10; Y10S; Y10S48/00; Y10S48/07
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
69 words
A method for burning a pulverized carbonaceous material containing sulfur and ash, comprising forming a slurry containing the carbonaceous material, water, a reagent adapted to react with the sulfur and a cementing agent, burning the slurry in a first stage with less than 100% theoretical air, removing the combustible gases from the first stage to a second stage, and burning the gases in the second stage with additional air.
Claim 2
Independent Claim
69 words
A method for burning a pulverized carbonaceous material containing sulfur and ash, comprising forming a slurry containing the carbonaceous material, water, a reagent adapted to react with the sulfur and a cementing agent, burning the slurry in a first stage with less than 100% theoretical air, removing the combustible gases from the first stage to a second stage, and burning the gases in the second stage with additional air.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein the slurry is burned in the first stage at a temperature below about 1100° C.
Claim 4
Dependent Claim
24 words
The method of claim 1 wherein the slurry is burned in the first stage at a temperature between about 850° C. and 1050° C.
Claim 5
Dependent Claim
20 words
The method of claim 1 wherein the amount of water in the slurry is not more than 45% by weight.
Claim 6
Dependent Claim
12 words
The method of claim 1 wherein the cementing agent is calcium oxide.
Claim 7
Dependent Claim
26 words
The method of claim 1 wherein the amount of reagent in the slurry is not less than the stoichiometric amount necessary to react with the sulfur.
Claim 8
Dependent Claim
30 words
The method of claim 1 wherein the reagent is selected from the group consisting of calcium oxide, calcium carbonate, dolomite, magnesium oxide, sodium carbonate, sodium bicarbonate, clay and mixtures thereof.
Claim 9
Dependent Claim
18 words
The method of claim 1 wherein the reagent is adapted to reduce the melting temperature of the ash.
Claim 10
Dependent Claim
18 words
The method of claim 1 wherein the reagent is adapted to increase the melting temperature of the ash.
Claim 11
Dependent Claim
22 words
The method of claim 1 wherein the air in the first stage is introduced at a velocity of at least 0.3 meters/sec.
Claim 12
Dependent Claim
13 words
The method of claim 1 wherein the slurry contains a particulate binding agent.
Claim 13
Dependent Claim
20 words
The method of claim 11 wherein the amount of binding agent in the mixture is at least 2% by weight.
Claim 14
Dependent Claim
25 words
The method of claim 11 wherein the binding agent is selected from the group consisting of clay, sucrose, calcium acetate, acetic acid and mixtures thereof.
Claim 15
Independent Claim
94 words
A method of burning a pulverized carbonaceous material containing sulfur and ash, comprising forming a slurry containing between 45% and 65% by weight of the carbonaceous material, between 30% and 45% by weight water and between 5% and 15% by weight calcium oxide, allowing the slurry to harden by reaction of the water with the calcium oxide, burning the slurry in a first stage with less than 100% theoretical air, removing the products of combustion from the first stage to a second stage, and burning the products in the second stage with additional air.
Claim 16
Independent Claim
94 words
A method of burning a pulverized carbonaceous material containing sulfur and ash, comprising forming a slurry containing between 45% and 65% by weight of the carbonaceous material, between 30% and 45% by weight water and between 5% and 15% by weight calcium oxide, allowing the slurry to harden by reaction of the water with the calcium oxide, burning the slurry in a first stage with less than 100% theoretical air, removing the products of combustion from the first stage to a second stage, and burning the products in the second stage with additional air.
Claim 17
Dependent Claim
16 words
The method of claim 14 wherein the slurry is allowed to harden for about one hour.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-01-04 | 1985-07-06 | 1986-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-04 | 1989-07-06 | 1990-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-04 | 1993-07-06 | 1994-01-05 | $7700.00 | Window Closed / Lapsed |