US3554517A

US3554517A - Shaft furnace shell cooling system

Info

Publication number: US3554517A
Application number: US776719A
Authority: US
Inventors: William G Seacrest
Original assignee: Bethlehem Steel Corp
Current assignee: Bethlehem Steel Corp
Priority date: 1968-11-18
Filing date: 1968-11-18
Publication date: 1971-01-12
Anticipated expiration: 1988-01-12

Abstract

A cooling system for a shaft furnace having horizontal rows of stave coolers installed between the outer shell and the inner refractory lining. The upper ends of each row of coolers are spaced from the furnace shell a greater distance than the lower ends of the coolers of the next higher row.

Description

United States Patent Inventor William G. Seacrest Coopersburg, Pa.

Appl. No. 776,719

Filed Nov. 18,1968

Patented Jan. 12, 1971 Assignee Bethlehem Steel Corporation a corporation of Delaware SHAFT FURNACE SHELL COOLING SYSTEM 5 Claims, 3 Drawing Figs.

US. Cl 266/32,

lnt. c1 C2lb 7/10 Field of Search 266/32, 43, 25; 263/44; 264/30 [56] References Cited UNITED STATES PATENTS 452,607 5/1891 Hunt 266/32 2,291,938 8/l942 Agnew 266/43 3,379,427 4/1968 Zherebin et al 266/32 Primary ExaminerGerald A. Dost Att0rney.loseph J. OKeefe PATENTED JAN 1 212m INVENTOR Will/am G. Seacrcsf SHAFT FURNACE SHELL COOLING SYSTEM BACKGROUND OF THE INVENTION This invention relates to a cooling system for shaft furnaces and more particularly to a stave cooler system which is interposed between the shell and the refractory lining of such a furnace.

High operating temperatures of metallurgical shaft furnaces, particularly blast furnaces, necessitate the use of some manner of cooling in order to protect the structural integrity of the furnace shell and to prolong the usable life of the refractory lining. Conventionally, the cooling systems for such furnaces include a plurality of rows of cast copper cooling plates which extend horizontally through the shell into the refractory lining. A more recently developed and less frequently used system peripherally cools shaft furnaces by means of stavetype coolers. These coolers are sometimes referred to as shannon plates, peripheral plates, peripheral coolers, or bosh or stack staves. Stave coolers are large curved plates which extend vertically and circumferentially of theinterior of the furnace shell to which they are bolted. The rows of coolers are stacked one on top of another, parallel to the furnace shell, and the space between shell and coolers is filled with a grout or synthetic material.

Studies indicate that stave cooler systems have several advantages, e.g., they provide more uniform cooling than systems which utilize the more conventional cast copper coolers; however, there are several problems associated with stave cooler systems. The installation of rows of stave coolers, one on top of another is troublesome, particularly in the upwardly and inwardly tapering stack section of a shaft furnace. The relatively smooth surface presented by the stave cooler system does not promote the formation of a protective layer of hardened slag on the inner surfaces of the coolers after the lining has been worn away. In addition, incremental vertical expansion that may occur due to overheating of one or more coolers is transmitted to coolers of adjacent rows, thereby placing stresses on the entire installation.

SUMMARY OF THE INVENTION It is an object of this invention to provide a shaft furnace cooler system which is simple in design, easy to install, and effective in operation.

Another object of this invention is to provide a shaft furnace stave cooler system which confines incremental vertical expansion of a cooler due to overheating to the individual overheated cooler.

A further object of this invention is to provide a shaft furnace stave cooler system which will function to promote the formation of a protective layer of slag on the cooler surfaces when the refractory lining in front of the coolers has been worn away.

The objects of this invention are achieved a in a shaft furnace having a plurality of horizontal rows of stave coolers by spacing the upper ends of the coolers of each row a greater distance from the furnace shell than the lower ends of the coolers in the next higher row.

BRIEF DESCRIPTION OF THE DRAWING Referring to the drawing:

FIG, 1 is a view in longitudinal section of a portion of a blast furnace embodying the present invention.

FIG. 2 is an enlarged view of a portion of the furnace of FIG. 1 showing the brick lining removed and the stave coolers exposed.

FIG. 3 is an enlarged view, partly in section, taken on the line 3-3 of FIG. 2.

PREFERRED EMBODIMENT OF THE INVENTION Referring to the drawing there is shown in FIG. 1 a metallurgical blast furnace having hearth 11, bosh 12, and stack 13. Stack 13 comprises the usual metal jacket or shell 14 which extends upwardly from mantle l5 and is lined with refractory bricks 16. The upper portion of stack 13 is protected from high furnace operating temperatures by means of vertically spaced circumferential rows of conventional cast copper coolers 17 set radially into the lining and suitably mounted at their outer ends in shell 14. The lower portion of stack 13, sometimes referred to as the hot zone, is protected by peripheral cooling system of 18 of this invention.

Cooling system 18 comprises a pluralityof circumferential rows 19A to 19H of stave coolers 20, which may be of any 7 convenient height H.

Each stave cooler 20 has top 21, bottom 22, sides 23, inner or refractory side surface 24 and outer or shell side surface 25. Secured to shell side surface 25 of each cooler is water circulating conduit 26. Water inlet pipe 27, from a source not shown, is connected to one end of conduit 26 and water discharge pipe 28 is connected to the other end of the conduit. Water inlet and

discharge pipes

27 and 28, respectively, extend through openings 29 in shell 14 which are sealed in a convenient manner.

Except for coolers 20 in bottom row 19A which extend upwardly from mantle 15, coolers 20 of rows l9Bl9H rest upon brackets 30 which are arranged in a plurality of vertically spaced circumferential rows, a portion of which are shown in FIG. 2 as

rows

31B, 31C, and 31D that support

cooler rows

19B, 19C and 19D, respectively. Bracket rows, as for

example rows

31B, 31C and 31D, are spaced apart a distance D along shell 14. Brackets 30 are joined to shell 14 in any suitable manner; as by welding, and each bracket is separated from adjoining ones in the same row by a gap 32 in order to avoid the possibility of stresses being set up in the shell in the event a bracket becomes overheated. The bottoms 22 of staves 20 in a row, except for the staves of bottom row 19A, are spaced from the inner surface of shell 14 a distance d, as shown in FIGS. 2 and 3, and in this space closure plate 33 extends across gaps 32 for reasons hereinafter explained.

Staves 20 of bottom row 19A extend vertically upward from mantle 15 to brackets 30 of bracket row 31B. The inner surfaces of staves 20 of row 19A, adjacent their tops, are close to or in contact with the inner ends of brackets 30 of row 31B, and the tops 21 of these staves are slightly above the topsurface of these brackets and overlap the lower inner surfaces 24 of staves 20 of stave row 19B, thenext higher row. Staves 20 of second row 19B extend from the top surfaces of brackets 30 of row 31B upwardly and inwardly of the furnace to brackets 30 of the next higher row 31C. The outer surfaces 25 of staves 20 of row 19B, adjacent their tops, are close to or in contact with the inner ends of brackets 30 of row 31C, and the tops 21 of these staves are slightly above the top surfaces of the brackets and overlap the lower inner surfaces 24 of staves 20 of stave row 19C, the next higher row. In like fashion, staves 20 of the remaining stave rows l9C-l9H extend from the top surfaces of their respective supporting brackets 30 upwardly and inwardly of the furnace to the next higher row of supporting brackets and overlap the bottoms of the staves 20 of the next higher row. Staves 20 are secured in place by means of bolts 34 which pass through openings-35 in shell 14 that are sealed in any convenient way. Any spaces between coolers are caulked with a high temperature caulking material such as asbestos rope and the space 36 between the outer surfaces 25 of staves 20 and the inner surface of shell 14 is filled with a castable material 36, as the rows of coolers are set in place.

In the above described stave cooling system of this invention, the height H of staves 20 is greater than the distance D between rows of brackets 30 so that the upper ends of staves 20 of each row of staves overlap brackets 30 which support the next higher row of staves. Staves 20, except for the staves in bottom row 19A, have their upper ends spaced a greater distance from shell 14 than their lower ends, and the upper ends of staves 20 of each row are farther from shell 14 than the lower ends of staves 20 of the next higher row. As viewed from the interior of the furnace, the upper ends of a row of staves overlap the lower ends of the staves of the next higher shell. in addition, the inverted shingle effect of the stave coolers confines local vertical expansion to a sn single stave and reduces critical installation tolerance. Finally, the upper surfaces 21 of staves 20 provide a shelf, initially to support refractory bricks 16 of the lining, and when these have worn away, to assist in the formation of a protective layer of hardened slag on the tops 21 and inner surfaces 24 of exposed staves. i I claim: p l. A cooling system for a stack furnace having an outer shell and an inner refractory lining, said system comprising:

a. a first row of stave coolers and a second row of stave coolers positioned above said first row, interposed between said shell and said refractory lining,

b. said first row of stave coolers having the upper ends thereof spaced a greater distance from said stack shell than the lower ends of said second row of stave coolers,

c. means to support each said row of stave coolers.

2. The cooling system of claim 1 wherein the upper ends of said first row of stave coolers and the lower ends of said second row of stave coolers overlap.

3. The cooling system of claim 1 wherein said'first row of stave coolers have the upper ends thereof spaced from said furnace shell a greater distance than the lower ends thereof.

4. The cooling system of claim 1 wherein each said support means for a row of said stave coolerscomprises a structural member secured to the inner surface of said shell and extending inwardly therefrom.

5. The cooling system of claim 4 wherein the distance between said support members for said first and second rows of stave coolers is less than the height of said cooler plates of said first row.

Claims

1. A cooling system for a stack furnace having an outer shell and an inner refractory lining, said system comprising: a. a first row of stave coolers and a second row of stave coolers positioned above said first row, interposed between said shell and said refractory lining, b. said first row of stave coolers having the upper ends thereof spaced a greater distance from said stack shell than the lower ends of said second row of stave coolers, c. means to support each said row of stave coolers.

3. The cooling system of claim 1 wherein said first row of stave coolers have the upper ends thereof spaced from said furnace shell a greater distance than the lower ends thereof.

4. The cooling system of claim 1 wherein each said support means for a row of said stave coolers comprises a structural member secured to the inner surface of said shell and extending inwardly therefrom.