US4616576A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Combustion method
Assignee: Amec Foster Wheeler Energia Oy
•
Filing: 1985-05-29
•
Granted: 1986-10-14
•
Expires: 2005-05-29
Abstract
Abstract In a two-stage combustion method first and second circulating fluidizing bed systems are utilized. The first bed system is operated under reducing (sub-stoichiometric) conditions so as to minimize NO x formation. Solids in the flue gases are separated and returned to the first bed system, while the flue gases are subjected to afterburning in the second bed system. Oxygen containing gas is supplied to the second bed system to effect afterburning, and additionally sulfur absorbing and/or NO x formation decreasing agents are supplied to the second system. When burning coal, the first system is operated at a temperature of about 700°-1000° C., while the second system is operated at about 600°-950° C. The flue gases may be cooled, just prior to effecting separation of the solids, in one or both of the bed systems.
Inventors
- 👤 Folke Engstrom
- 👤 Bertel K. Hakulin
- 👤 Seppo K. Ruottu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:52
CPC Classifications
F; F23; F23C; F23C10/00; F23C10/02; F23C10/04; F23C10/08; F23C10/10; B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/508; B01D53/54; B01D53/56; B01J; B01J8/00; B01J8/18; B01J8/24; B01J8/26; B01J8/38; B01J8/384; B01J8/388; F22; F22B; F22B31/00; F22B31/0007; F22B31/0084; F23C10/005; F23C2206/00; F23C2206/10; F23C2206/101
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
143 words
A two-stage combustion method utilizing first and second circulating fluidizing bed systems, comprising the steps of: supplying fuel to the first circulating fluidizing bed system, the fuel remaining fluidized during combustion thereof; operating the first system under reducing conditions to produce flue gases with combustible solids therein; separating the solids from the flue gases of the first system, recirculating the separated solids to the first system; introducing the flue gases, after separation of solids therefrom, from the first system into the second circulating fluidizing bed system; introducing oxygen containing gas into the second system to effect afterburning of the flue gases from the first system, and wherein in the second circulating fluidized bed system flue gases containing solids therein are produced; and separating the solids from the second bed system flue gases, and returning the separated solids to the second circulating bed system.
Claim 2
Dependent Claim
143 words
A two-stage combustion method utilizing first and second circulating fluidizing bed systems, comprising the steps of: supplying fuel to the first circulating fluidizing bed system, the fuel remaining fluidized during combustion thereof; operating the first system under reducing conditions to produce flue gases with combustible solids therein; separating the solids from the flue gases of the first system, recirculating the separated solids to the first system; introducing the flue gases, after separation of solids therefrom, from the first system into the second circulating fluidizing bed system; introducing oxygen containing gas into the second system to effect afterburning of the flue gases from the first system, and wherein in the second circulating fluidized bed system flue gases containing solids therein are produced; and separating the solids from the second bed system flue gases, and returning the separated solids to the second circulating bed system.
Claim 3
Dependent Claim
24 words
A method as recited in claim 1 comprising the further step of supplying a sulfur absorbing agent to the second circulating fluidizing bed system.
Claim 4
Dependent Claim
25 words
A method as recited in claim 2 comprising the further step of supplying an NO x formation decreasing agent to the second circulating bed system.
Claim 5
Dependent Claim
27 words
A method as recited in claim 3 comprising the further step of cooling the flue gases from the second bed system before effecting separation of solids therefrom.
Claim 6
Dependent Claim
26 words
A method as recited in claim 4 comprising the further step of cooling the flue gases from the first bed system before separating the solids therefrom.
Claim 7
Dependent Claim
25 words
A method as recited in claim 1 comprising the further step of supplying an NO x formation decreasing agent to the second circulating bed system.
Claim 8
Dependent Claim
27 words
A method as described in claim 1 comprising the further step of cooling the flue gases from the second bed system before effecting separation of solids therefrom.
Claim 9
Dependent Claim
26 words
A method as recited in claim 7 comprising the further step of cooling the flue gases from the first bed system before separating the solids therefrom.
Claim 10
Dependent Claim
26 words
A method as recited in claim 1 comprising the further step of cooling the flue gases from the first bed system before separating the solids therefrom.
Claim 11
Dependent Claim
67 words
A method as recited in claim 7 wherein the fuel introduced into the first bed system is coal, and comprising the further steps of controlling the combustion process in the first and second bed systems so that the temperature in the first bed system is within range of 700°-1000° C., and so that the temperature in the second bed system is in the range of 600°-950° C.
Claim 12
Dependent Claim
67 words
A method as recited in claim 9 wherein the fuel introduced into the first bed system is coal, and comprising the further steps of controlling the combustion process in the first and second bed systems so that the temperature in the first bed system is within range of 700°-1000° C., and so that the temperature in the second bed system is in the range of 600°-950° C.
Claim 13
Dependent Claim
67 words
A method as recited in claim 1 wherein the fuel introduced into the first bed system is coal, and comprising the further steps of controlling the combustion process in the first and second bed systems so that the temperature in the first bed system is within range of 700°-1000° C., and so that the temperature in the second bed system is in the range of 600°-950° C.
References Cited (Backward Citations)
US3366080A
Cited
US3888193A
Cited
US4159682A
Cited
US4159682B1
Cited
DE2945544A1
Cited
US4324544A
Cited
US4355601A
Cited
US4416418A
Cited
US4446799A
Cited
US4434726A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-10-13 | 1990-04-14 | 1990-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-10-13 | 1994-04-14 | 1994-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-10-13 | 1998-04-14 | 1998-10-14 | $7700.00 | Window Closed / Lapsed |