Patent US4369719A successfully refreshed from Google Patents.
US4369719A
Expired / Lapsed
US
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Vermiculite as a deposit modifier in coal fired boilers
Assignee: WR Grace and Co Conn
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Filing: 1980-11-14
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Granted: 1983-01-25
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Expires: 2000-11-14
Abstract
Abstract Uncalcined vermiculite is injected into the coal fired furnace, at 3000 DEG -1200 DEG F., thereby facilitating removal of deposits that accumulate on line within the furnace.
Inventors
- 👤 Gary G. Engstrom
- 👤 Douglas I. Bain
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:35
CPC Classifications
F; F23; F23J; F23J3/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
31 words
Method of rendering fly ash deposits in a coal-fired furnace more friable, thereby facilitating their removal by steam or air probe, comprising injecting uncalcined vermiculite into the furnace at 3000°-1200° F.
Claim 2
Dependent Claim
31 words
Method of rendering fly ash deposits in a coal-fired furnace more friable, thereby facilitating their removal by steam or air probe, comprising injecting uncalcined vermiculite into the furnace at 3000°-1200° F.
Claim 3
Dependent Claim
25 words
Method according to claim 1 in which the vermiculite is injected at the rate of about 1 to 3 pounds per short ton of coal.
Claim 4
Dependent Claim
15 words
Method according to claim 1 in which the vermiculite is about 80 to 150 mesh.
Claim 5
Dependent Claim
20 words
Method according to claim 1, claim 2, or claim 3 in which the temperature of injection is about 2600° F.
Claim 6
Dependent Claim
45 words
Method according to claim 1, claim 2, or claim 3 in which the furnace is a boiler having a superheater and convection passes and the vermiculite is injected into the boiler so that vermiculite is incorporated in the deposits on the superheater and convection passes.
Claim 7
Dependent Claim
28 words
Method according to claim 1 or claim 3 in which the vermiculute is injected at the rate of about 0.05 to 10.0 pounds per short ton of coal.
Claim 8
Dependent Claim
60 words
Method of rendering fly ash deposits in a coal-fired boiler having a superheater and convection passes more friable, thereby facilitating their removal by steam or air probe, comprising injecting unexfoliated vermiculite into the boiler flue gas stream at a temperature of about 3000° to 1200° F. so that vermiculite is incorporated in the deposits on the superheater and convection passes.
Claim 9
Dependent Claim
60 words
Method of rendering fly ash deposits in a coal-fired boiler having a superheater and convection passes more friable, thereby facilitating their removal by steam or air probe, comprising injecting unexfoliated vermiculite into the boiler flue gas stream at a temperature of about 3000° to 1200° F. so that vermiculite is incorporated in the deposits on the superheater and convection passes.
Claim 10
Dependent Claim
25 words
Method according to claim 7 in which the vermiculite is injected at the rate of about 0.05 to 10.0 pounds per short ton of coal.
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) | 1986-01-24 | 1986-07-26 | 1987-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-24 | 1990-07-26 | 1991-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-24 | 1994-07-26 | 1995-01-25 | $7700.00 | Window Closed / Lapsed |