Gas: heating and illuminating – Generators – Cupola
Reexamination Certificate
1998-07-13
2001-11-06
Beck, Shrive (Department: 1764)
Gas: heating and illuminating
Generators
Cupola
C048S077000, C048S202000
Reexamination Certificate
active
06312482
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to coal gasifiers and, in particular, to a new and useful combined, integral steam generator coal gasifier for converting coal into useable gas products while at the same time producing steam for electric power generation and/or process requirements.
2. Description of the Related Art
FIGS. 1-6
illustrate various known coal gasifier constructions with a wide variety of configurations, system parts and relationships.
In 1951, The Babcock & Wilcox Company (B&W) supplied an atmospheric-pressure, oxygen and steam-blown, slagging-type, entrained-flow gasifier to the U.S. Bureau of Mines at Morgantown, W. Va.
FIG. 1A
illustrates this device. In addition, B&W also supplied to the U.S. Bureau of Mines at Morgantown, W. Va., a pressurized oxygen-and steam-blown, slagging type, entrained flow gasifier; see FIG.
1
B. In the early 1950's B&W was involved in the supply of a semicommercial-size, atmospheric-pressure, oxygen-and steam-blown, slagging type, entrained flow gasifier to E. I. DuPont de Nemours (DuPont) at Belle, W. Va. which is shown in
FIG. 2
, followed by a commercial-size gasifier at the same location; see FIG.
3
. In the middle 1950's, B&W performed engineering studies and experimental work on air-blown, slagging-type, entrained-flow gasification for combined gas turbine-steam turbine cycles. This resulted in a joint project with General Electric Company where a gasifier was operated (over a 3 year period in the 1960's) at B&W's Alliance Research Center; please refer to FIG.
4
. In 1976, B&W constructed a gasifier for the Bi-Gas pilot plant at Homer City, Pa., which was sponsored by the U.S. Department of Energy; see FIG.
5
. B&W was also involved in a joint venture with Koppers Company, Inc. in the 1980's, known as KBW Gasification Systems, Inc. The KBW gasifier and auxiliary equipment are shown in FIG.
6
. Out of that grew the technology and design which is the basis for the present invention.
SUMMARY OF THE INVENTION
The present invention is drawn to a new combined, integral steam generator coal gasifier for converting coal into useable gas products, particularly synthesis gas, while at the same time producing steam for electric power generation and/or process requirements. The integral steam generator coal gasifier has unexpected and useful advantages over any of the previous designs.
Accordingly, one aspect of the present invention is drawn to an integral steam generator coal gasifier for simultaneously producing synthesis gas from coal, and steam from heat produced by a coal gasification process. The integral steam generator coal gasifier comprises a vertically elongated, all welded, gas tight enclosure having walls made from a plurality of membrane wall tube panels. The coal gasification process occurs within the enclosure and produces hot synthesis gas, and heat which is transferred to a mixture of water and steam flowing through the tube panels. The enclosure conveys the hot synthesis gas from a burner zone at a lower portion thereof to an outlet. A double pitch sloping furnace floor is provided at a bottom of the burner zone and having a slag tap extending therethrough to remove slag produced during the coal gasification process. A corrosion resistant zone is provided above the burner zone, while an upper cooling zone is provided above the corrosion resistant zone.
Advantageously, the enclosure walls of the corrosion resistant zone comprise one of bimetallic and/or composite membrane tube panels, while the enclosure walls of the upper cooling zone can merely comprise carbon steel membrane tube panels. A multi-pass convection pass zone is provided above the upper cooling zone, and the multi-pass convection pass zone defines a region containing heating surfaces which extract heat from the synthesis gas as it flows across the heating surfaces. Preferably, the convection pass zone comprises an upflow pass and a downflow pass for conveying the synthesis gas from the upper cooling zone to the outlet. The heating surfaces within the convection pass zone comprise superheater and economizer surfaces for extracting heat from the synthesis gas. The superheater surfaces comprise secondary and primary superheater surface in the upflow pass and economizer surface in the downflow pass. Part of the primary superheater may be located in both the upflow pass and the downflow pass; particularly, inlet bank(s) of the primary superheater may be located at the top of the downflow pass, while outlet bank(s) of the primary superheater may be located at the top of the upflow pass. Finally, ash removal means are provided, connected to an outlet of the convection pass zone for separating ash from the synthesis gas exiting from the convection pass zone, while slag removal means communicate with the slag tap for receiving slag from the burner zone.
Another aspect of the invention involves a construction wherein the sloped furnace floor and the walls of the burner zone are comprised of ribbed tubes having a pattern of pin studs thereon covered by a refractory material. Advantageously, the ribbed tubes are multi-lead ribbed tubes.
Various proven technologies are also used to improve the predictability and modeling of the coal gasifier and, in particular with regard to its burner flame, the furnace temperature, and the gasification reactions. In particular, these modeling techniques particularly influenced the burner and burner zone design configuration.
Thus, yet another aspect of the present invention involves the arrangement and orientation(s) of the burners with respect to the walls through which they fire (i.e., their associated wall). Generally, at least one elevation (preferably two) of offset burners is provided in the burner zone, burners provided and arranged so as to fire through each of the four (4) walls of the enclosure. The term offset means that a burner on one wall is not located directly opposite a burner on an opposite wall. Each of the offset burners are arranged to fire through their associated wall of the enclosure at an angle &thgr; with respect to a line perpendicular to the associated wall, angle &thgr; lying within a range of about 0 degrees to about 25 degrees. Preferably, however, angle &thgr; has a non-zero value lying within a range of about 15 degrees to about 25 degrees.
In addition, not only is there provided at least one elevation of offset burners in the burner zone, one burner being provided and arranged so as to fire through each wall of the enclosure, but each one burner is also located on its associated wall a distance away from a corner of the enclosure lying within a range of about one-fifth to about one-third of the width of the associated wall. Together with an appropriate value for angle &thgr;, a vortex is produced within the enclosure which enhances the coal gasification process.
Another aspect of the present invention involves the double pitch sloping furnace floor, and which preferably comprises a plurality of K-forgings which physically interconnect tubes forming the sloping furnace floor and fluidically interconnect them with headers located beneath the sloping furnace floor. Generally, each K-forging physically joins two tubes from opposite front and rear walls of the enclosure to form the double pitch sloping furnace floor.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to, and forming a part of, this disclosure. For a better understanding of the invention, its operating advantages and specific benefits attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.
REFERENCES:
patent: 4270493 (1981-06-01), Blaskowski
patent: 4328007 (1982-05-01), Rafael
patent: 4487612 (1984-12-01), Hebden et al.
patent: 5309848 (1994-05-01), Santelmann et al.
patent: 5390631 (1995-02-01), Albrecht
patent: 5425791 (1995-06-01), Tanca
Davey et al., An Advance
Godden Mark C.
James David E.
Larsen Paul S.
Mull, Jr. Ted V.
Weitzel Paul S.
Beck Shrive
Doroshenk Alexa A.
Edwards Robert J.
Kalka Daniel S.
Marich Eric
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