Cooling plate comprising a reinforcement element

Abstract

A cooling plate with reinforcing part for furnaces which are provided with a refractory lining. Coolant passages are arranged in the interior of the plate, which is provided with at least one additional cooling segment provided with a cooling passage into which a displacement body is inserted.

Description

[0001] The invention relates to a cooling plate with reinforcing part, for example a reinforced top and/or bottom end, for melting vessels which are used to produce pig iron, blast furnaces and shaft furnaces provided with a refractory lining, in particular including CORE® melter gasifiers, consisting of copper or a low-alloy copper alloy, with cooling passages arranged in its interior, the cooling plate being manufactured from a forged or rolled block, the cooling passages being vertically running blind bores, and tongues and grooves being machined onto the side which faces the interior of the shaft furnace.

[0002] Cooling plates of this type are usually arranged between the casing and the refractory lining and are connected to a cooling system. On the side facing the process space, the cooling elements are partially provided with refractory material.

[0003] DE 39 25 280 has disclosed a cooling plate in which the cooling passages are formed by pipes which are cast into cast iron, and the bottom edge of the plate body is designed as a bearing lug for the refractory brickwork. The bearing lug is likewise connected to the cooling system. Little heat is dispatched from these plates, on account of the low thermal conductivity of the cast iron and on account of the resistance between the cooling pipes and the plate body, caused by an oxide layer or an air gap.

[0004] After a certain operating time, the loss of the blast furnace refractory brickwork leads to the inner surface of the cooling plates being directly exposed to the temperature of the furnace. Since the furnace temperature is well above the melting point of cast iron and the internal heat transfer resistances of the cooling plates lead to unsatisfactory cooling of the hot plate side, accelerated wear to the cast iron plates is inevitable, and the service life is correspondingly limited.

[0005] Furthermore, plates made from cast copper, in which the cooling passages are formed either by cast-in tubes or are cast in directly by shaped casting, are known. The microstructure of cast copper is not as homogenous and dense as that of forged or rolled copper. Consequently, the conduction of heat in cast copper is not as good and the strength is lower. In the case of the cast-in pipe, an oxide layer between pipe and copper block inhibits heat conduction.

[0006] DE 29 07 511 has disclosed a cooling plate which is produced from a forged or rolled block and the cooling passages are vertically running blind bores which have been formed by deep mechanical drilling. The microstructure of the cooling plate is significantly denser and more homogenous than that of a cast copper plate. Voids, which are often found in cast copper plates, are prevented by the forming process. The strength values are higher and the thermal conductivity is more uniform and higher than that of the cast copper plates. Mechanical production of the bores means that the desired position in terms of height and lateral position is accurately maintained, and as a result uniform dissipation of heat is ensured. On the side facing the interior of the furnace, the cooling plate is lined with refractory bricks or with a refractory ramming compound. This reduces the cooling surface area of the plate, and in the event of wear to or loss of the pre-bricked refractory lining, extraction of heat from the furnace is limited. Furthermore, the cooling of the plate needs to be sufficiently intensive to keep the temperature of the hot side of the plate well below the softening point of copper.

[0007] DE-A 23 62 974 has disclosed a cooled shaft furnace with a steel casing, to the inner side of which cooling plates with substantially vertical inner tubes are connected; the tubes pass through the steel casing at the upper and lower ends of the cooling plate. On the side remote from the steel casing, the cooling plate is provided with a holding protuberance or holding lug, through which another tube, running in a substantially horizontal plane, runs, with connections leading through the steel casing; at least some of the vertical tubes extend over a considerable part of the vertical dimension.

[0008] FR-A 22 30 730 has disclosed a cooler for the evaporative cooling of a blast furnace, this cooler comprising a plate with a collar, which is arranged transversely in the vicinity of the end of the plate, and tubes, which are mounted in the plate and in the said collar and in which a coolant flows. The inlet and outlet ends of these tubes are arranged at different heights on the opposite side from the collar. The tube for circulation of the coolant in the collar is configured in such a way that it is arranged in the collar in such a way that the inlet and outlet ends are located between the outlet ends of the tubes laid in the plate. The ends of the parts of the circulation tube in the collar, which are located in the interior of this collar, are arranged at an angle of 2 to 4° with respect to the vertical, so that the circulation of the coolant from the inlet end to the outlet end of the tubes rises.

[0009] U.S. Pat. No. 4,071,230 has disclosed cooling elements for a shaft furnace which are secured to the inner side of the furnace shell. The rectangular cooling element is composed of five metallic blocks which are arranged in a staggered formation above one another and are attached to two vertically running pairs of cooling tubes by means of suitable securing elements. The pairs of tubes, with a cooling water inlet at the bottom and a cooling water inlet at the top, are routed through openings in the metallic furnace wall, and the metallic blocks are cooled only on the outer side of the side facing the blast furnace wall.

[0010] EP 0 705 906 A1 has disclosed a cooling plate which is manufactured from a forged or rolled copper block and in which cooling passages, which are introduced into the edges as vertical or horizontal blind bores of smaller diameter around the vertically arranged blind bores, are introduced in addition to the vertically running blind bores, in order to cool the edge zones.

[0011] However, a drawback of these rolled or forged copper cooling plates is that the load-bearing capacity of the refractory brickwork lining at the top ends of the cooling plate is less than optimal and consequently the service lives of the refractory ramming compounds or refractory bricks is also inadequate.

[0012] EP 0 731 108 B1 describes a cooing plate with reinforced and cooled top end. The cooling passages at the reinforcement are characterized by their arrangement and/or by the fact that they are produced by vertical and horizontal blind bores. The cooling medium is supplied and discharged via cooling pipes, which may be included in the cooling system of the shaft furnace.

[0013] A drawback of this variant is the complicated and laborious production of the cooled top end, which often requires the tools to be changed during production of the blind bores. A plurality of welds or soldered joints are required to tightly close off these blind bores. For production reasons, these welds and joints are very close to the process chamber and are highly susceptible to failure. It is therefore desirable to minimize the number of these welds and joints. In addition, the cooling passage surface area which is required to achieve the required cooling capacity is limited by the geometric design of the attached refractory supports.

[0014] Therefore, the object of the invention is to provide a cooling plate with reinforcing part in which cooling and dissipation of heat in this reinforcing part are likewise uniform and homogenous, so that there too, improved cooling of the refractory furnace lining and of the furnace shell is ensured. In addition, the number of welds required should be reduced to a minimum, and at the same time the available heat exchange surface area should be increased.

[0015] This object is achieved by virtue of the fact that at least one additional cooling segment is provided, which is provided with a cooling passage into which a displacement body is inserted.

[0016] Surprisingly, it has been discovered that it is not necessary to provide a complicated combination of vertical and horizontal blind bores for the additional cooling segment. Rather, it has been established that to achieve the required cooling action it is sufficient for an additional cooling segment, which may be detachable and into which a cooling passage formed by a horizontal bore is introduced, to be fitted to the forged or rolled copper cooling plate, for example in the upper or lower region. To achieve the optimum flow velocity which is required for the heat transfer, a displacement body is additionally inserted into this bore. The bore is closed off in a sealed manner at the end by welded or soldered stoppers and is connected to the cooling system via copper pipe connection pieces.

[0017] As an alternative to a releasable cooling segment, it is also possible for a bead for the refractory brickwork to be forged out of the copper block, in which case the cooling passages are drilled into this bead in the known way.

[0018] To keep the heat exchange surface area of the cooling passage as large as possible, it is advantageous for the diameter of the cooling passage to be selected to be as large as possible, and at least to be larger than the diameter of the coolant passages of the cooling plate.

[0019] According to a further advantageous embodiment of the cooling plate according to the invention, the displacement body is designed as a cavity for routing coolant.

[0020] In an embodiment of this type, the displacement body expediently includes apertures which allow cooling medium to pass out of the cooling passage into the interior of the displacement body and from the latter back into the cooling passage.

[0021] According to an advantageous embodiment, bores for supplying and discharging cooling water open out into the cooling passage.

[0022] According to an alternative embodiment, pipe sections for supplying and discharging cooling water open out into the displacement body, which is designed as a cavity, in which case the pipe sections are pushed into the bores and are screwed to the displacement body at the location where they open out.

[0023] The bores for supplying and discharging cooling water may be designed so as to run horizontally or at an angle.

[0024] The invention is explained in more detail on the basis of diagrammatic embodiment drawings, in which:

[0025] FIG. 1 shows a horizontal section through the cooling plate with fitted refractory support,

[0026] FIG. 2 shows a cross section through the cooling plate with a forged-out bead,

[0027] FIG. 3 shows a cross section through a releasably attached cooling segment.

[0028] FIG. 1 shows a horizontal section through the cooling plate 1 with, by way of example, five vertically arranged blind bores 3 and with the cooling passage 5, which is introduced in the cooling segment 4 and is formed by a horizontal bore, and the inserted displacement body 6.

[0029] The cooling water is supplied to the blind bores 3 from below via the pipe attachments 2, which are connected to the coolant supply lines, and the cooling passage 5 formed by the horizontal bore in the cooling segment 4 is likewise supplied with cooling water via pipe sections 2. Bores 7 are also arranged in the cooling plate 1, in order to ensure the supply and removal of cooling water through the wall of the blast furnace shell via the pipe attachments 2. The cooling circuit of the cooling plate 1 and of the cooling segment 4 may be connected to the cooling system either as separate cooling circuits or as a common cooling circuit. The displacement body 6 has apertures 11, which allow cooling water to pass out of the cooling passage 5 into the interior of the displacement body 6 and back out of the displacement body 6 into the cooling passage 5. The direction of flow of cooling water is indicated by arrows.

[0030] FIG. 2 shows a section through the cooling plate 1 with the vertically arranged blind bores 3, which are closed off in a known way at the lower or upper end, as desired, by welds or soldered joints. Cooling water is supplied and discharged via the pipe sections 2. A cooling bead 8, which is forged out of the block and into which the cooling passage 5 formed by the horizontal bore is introduced, is formed in the upper part of the cooling plate 1. Once again, a displacement body 6 is inserted in the cooling passage 5, in order to ensure the appropriate flow velocity.

[0031] In this case, cooling water is supplied and discharged via inclined bores 7. A pipe section 12, which leads all the way into the displacement body 6 and is screwed to the latter, is inserted into each inclined bore 7. In the embodiment illustrated in FIG. 2, therefore, coolant is supplied into and discharged from the displacement body 6, whereas in the embodiment illustrated in FIG. 1 it is supplied into and discharged from the cooling passage 5.

[0032] For the introduction of refractory material, either bricks or spraying/ramming compounds, grooves 9, which are in each case delimited by webs 10, are machined into the cooling plate 1 and into the cooling bead 8 on the side facing the process chamber.

[0033] FIG. 3 shows a releasably fitted cooling segment 4, into which a cooling passage 5 formed by a horizontal bore has been introduced. The displacement body 6 is also illustrated. In this case too, this horizontal bore 5 is connected to the cooling circuit via horizontal bores 7 in the cooling plate 1 and then subsequently via pipe connections 2 leading through the wall of the shell.

[0034] List of Reference Symbols

[0035] 1 Cooling plate

[0036] 2 Pipe connections/pipe pieces

[0037] 3 Blind bores in 1

[0038] 4 Cooling segment

[0039] 5 Cooling passage in 4 and in 8

[0040] 6 Displacement body

[0041] 7 Bores in 1, 4 and 8 for supplying and discharging cooling medium

[0042] 8 Reinforced cooling segment/bead

[0043] 9 Grooves in 1, 4 and 8

[0044] 10 Webs on 1, 4 and 8

[0045] 11 Apertures in 6

[0046] 12 Pipe section in 7

Claims

1.-6. (Canceled)

7. A cooling plate with a reinforcing part for a furnace having a refractory lining, wherein the cooling plate comprises a plate having an extent along the lining, the plate having an interior; first coolant passages defined in the interior of the plate, at least one additional cooling segment of the plate; a second cooling passage defined in the segment, the second cooling passage running substantially horizontially and parallel to the extent of the cooling plate along the refractory lining; a displacement body inserted into the second cooling passage, the displacement body including a cavity therethrough for routing coolant along the cavity.

8. The cooling plate as claimed in claim 7, wherein the first coolant passages in the cooling plate have first diameters, the second cooling passage in the at least one additional cooling segment has a second diameter which is greater than the respective first diameters of the first coolant passages in the cooling plate.

9. The cooling plate as claimed in claim 7, wherein the at least one additional cooling segment is separate from and is secured releasably to the cooling plate.

10. The cooling plate as claimed in claim 7, wherein the at least one additional cooling segment is formed by a bead which is forged out of the cooling plate.

11. The cooling plate as claimed in claim 7, further comprising bores for supplying and discharging cooling water, and the bores opening out into the second cooling passage.

12. The cooling plate as claimed in claim 11, further comprising pipe sections inserted in the bores for supplying and discharging cooling water, and the pipe sections opening out into the displacement body.

13. The cooling plate as claimed in claim 8 further comprising a communication between the cavity in the displacement body and the second cooling passage in the at least one additional cooling segment.

14. A furnace for metal, comprising an interior furnace wall, a refractory material lining inside the interior wall; a cooling plate having an extent along the lining having and disposed between the interior furnace wall and the lining; the plate having an interior; first coolant passages defined in the interior of the plate, at least one additional cooling segment of the plate; a second cooling passage defined in the segment, the second cooling passage running substantially horizontially and parallel to the extent of the cooling plate along the refractory lining; a displacement body inserted into the second cooling passage, the displacement body including a cavity therethrough for routing coolant along the cavity.