US4285283A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coal combustion process
Assignee: ExxonMobil Technology and Engineering Co
•
Filing: 1979-12-07
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Granted: 1981-08-25
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Expires: 1999-12-07
Abstract
Abstract Disclosed is a process for combusting coal wherein the emission of SOx or the emission of SOx and NOx are minimized. The process comprises (a) providing a coal containing at least twice as much organic calcium than sulfur; (b) burning the coal at a temperature greater than about 1200 DEG C. under reducing conditions; (c) separating the solid effluents from the gaseous effluents; and (d) burning the gaseous effluents at a temperature from about 1000 DEG C. to 1500 DEG C. under oxidizing conditions.
Inventors
- 👤 Richard K. Lyon
- 👤 Howard Freund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:04
CPC Classifications
F; F23; F23C; F23C6/00; F23C6/04
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
135 words
A coal combustion process wherein the emission of SO x is minimized which process comprises: (a) providing a coal containing an organic calcium to sulfur ratio of at least 2 to 1 for coal containing less than 1 wt.% sulfur and at least 1 to 1 for coal containing greater than 1 wt.% sulfur; (b) burning the coal at temperatures greater than about 1200° C. in a first combustion zone in the presence of an oxidizing agent but under reducing conditions such that the equivalence ratio of coal to oxidizing agent is at least 1.5; (c) separating the resulting solid effluent from the gaseous effluent from the first combustion zone; and (d) burning the gaseous effluent at a temperature from about 1000° C. to about 1500° C. in a second combustion zone under oxidizing conditions.
Claim 2
Dependent Claim
135 words
A coal combustion process wherein the emission of SO x is minimized which process comprises: (a) providing a coal containing an organic calcium to sulfur ratio of at least 2 to 1 for coal containing less than 1 wt.% sulfur and at least 1 to 1 for coal containing greater than 1 wt.% sulfur; (b) burning the coal at temperatures greater than about 1200° C. in a first combustion zone in the presence of an oxidizing agent but under reducing conditions such that the equivalence ratio of coal to oxidizing agent is at least 1.5; (c) separating the resulting solid effluent from the gaseous effluent from the first combustion zone; and (d) burning the gaseous effluent at a temperature from about 1000° C. to about 1500° C. in a second combustion zone under oxidizing conditions.
Claim 3
Dependent Claim
24 words
The process of claim 1 wherein the equivalence ratio of coal to oxidizing agent in the first combustion zone is about 2 to 4.
Claim 4
Dependent Claim
16 words
The process of claim 1 wherein the solid effluent is treated to reduce its sulfur content.
Claim 5
Dependent Claim
139 words
A coal combustion process wherein the emission of SO x and NO x is minimized which process comprises: (a) providing a coal containing an organic calcium to sulfur ratio of at least 2 to 1 for coal containing less than 1 wt.% sulfur and at least 1 to 1 for coal containing greater than 1 wt.% sulfur; (b) burning the coal at temperatures greater than about 1400° C. in a first combustion zone in the presence of an oxidizing agent but under reducing conditions such that the equivalence ratio of coal to oxidizing agent is at least 1.5; (c) separating the resulting solid effluent from the gaseous effluent resulting from the first combustion zone; and (d) burning the gaseous effluent at a temperature from about 1000° C. to about 1500° C. in a second combustion zone under oxidizing conditions.
Claim 6
Dependent Claim
139 words
A coal combustion process wherein the emission of SO x and NO x is minimized which process comprises: (a) providing a coal containing an organic calcium to sulfur ratio of at least 2 to 1 for coal containing less than 1 wt.% sulfur and at least 1 to 1 for coal containing greater than 1 wt.% sulfur; (b) burning the coal at temperatures greater than about 1400° C. in a first combustion zone in the presence of an oxidizing agent but under reducing conditions such that the equivalence ratio of coal to oxidizing agent is at least 1.5; (c) separating the resulting solid effluent from the gaseous effluent resulting from the first combustion zone; and (d) burning the gaseous effluent at a temperature from about 1000° C. to about 1500° C. in a second combustion zone under oxidizing conditions.
Claim 7
Dependent Claim
24 words
The process of claim 4 wherein the equivalence ratio of coal to oxidizing agent in the first combustion zone is about 2 to 4.
Claim 8
Dependent Claim
16 words
The process of claim 4 wherein the solid effluent is treated to reduce its sulfur content.
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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) | 1984-08-24 | 1985-02-23 | 1985-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-24 | 1989-02-23 | 1989-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-24 | 1993-02-23 | 1993-08-25 | $7700.00 | Window Closed / Lapsed |