EP2847531B1 - Side wall cooling system for a melting furnace - Google Patents

Description

Field of the invention

The present invention relates to a device for cooling a metal melting furnace, in particular a reduction furnace.

State of the art

Melting furnaces, in particular reduction furnaces, contain hot metal melts covered by a slag layer. This slag layer is often very aggressive and can degrade the wall lining of the furnace.

As a rule, the furnace vessel in the interior comprises a lining, which is in direct contact with the melt or slag. In order to avoid damage or destruction of the furnace vessel and the resulting downtime and costs, the inner wall of the furnace must be constantly cooled. On the outside of the lining is often a metal armor, which is cooled, for example, with an open trickle cooling. In this case, large amounts of water are needed, which also run partly uncontrolled. Another disadvantage is that, in the case of cracks in the armor, water can enter the lining or melt or slag, which can cause undesirable and dangerous chemical reactions. In other facilities, water boxes are mounted on a side of the armor facing away from the melt and flooded with water. Thus, although the water can cool the armor over a large area and reasonably controlled, but the cooling is relatively far away from the actual heat source in the form of liquid slag.

From the WO 02/084192 A1 a cooling element for cooling a metallurgical furnace is known, wherein the furnace shell of the furnace is delivered to its furnace interior facing side with refractory material. The cooling element comprises a cooling part through which a coolant flows and which has a coolant inlet and a coolant outlet, as well as a heat section cooled by heat conduction. The hot part of the cooling element in the installed state is flush with the front side of the refractory material pointing into the interior of the furnace. The entire hot part is formed as a plate and this plate is cold side associated with a separate cooling part.

The European patent EP 0 741 853 B1 discloses a cooling device for an oven wherein rod-like copper rods extend into a furnace wall. On the back of the furnace wall is, for example, a metal plate, which is cooled over a large area by a water tank. A disadvantage of the disclosed arrangement is first the complex and costly production of the disclosed system. Furthermore, when using a continuous copper plate as adjacent to the furnace wall back wall, extending from this plate copper rods, large amounts of copper are needed. In addition, the carrying capacity of copper is limited, so that large material thicknesses are needed to achieve the necessary stability. Finally, a lining between the copper rods is considerably more difficult.

The technical object of the present invention is to provide a further developed cooling device for a melting furnace, in particular for cooling the slag region of the furnace - not the molten metal bath underneath.

In particular, such a device should be safe, enable a good cooling performance and / or be inexpensive to produce.

Preferably, such a device should also be used for rotary kilns.

Another object may be to overcome at least one of the above disadvantages.

Disclosure of the invention

Said technical problem is solved by the features of claim 1. Accordingly, the present invention relates to a cooling device for a melting furnace, in particular for cooling a liquid slag in a reduction furnace. In this case, the device comprises a lining for (side) shielding of a liquid molten metal bath and a molten slag located on the molten metal, and a metal plate (or a metal armor, in particular a steel plate), which on one side of the lining opposite the molten metal bath and the slag is arranged. The metal plate comprises a plurality of substantially vertically aligned and (in a horizontal direction) juxtaposed slots, wherein at least one, preferably each of the slots each one of the copper plates extends substantially perpendicular to the metal plate in the lining and the device further with Coolant flow-through cooling channels comprises, which are each arranged between two juxtaposed slots and extending through these slots copper plates on the side facing away from the molten metal bath and the slag side of the metal plate.

This solution is above all an effective as well as economical cooling. On the one hand, the copper plates extend into the lining, on the other hand, a cost-effective and effective cooling of the areas between the copper plates is possible. The revealed device can also be used in rotary kilns, for which a production of copper elements for cooling a brick lining is often difficult. In addition, the demand for copper can be kept low in view of rising commodity prices. In particular, the metal plate may be formed of steel or a steel alloy, whereby a high stability as well as a cost saving is made possible. In addition, the invention is particularly advantageous in the case of aggressive slag baths, in which it is of great importance that the liquid slag solidifies or "freezes" on the lining or on the copper plates. The slag layer thus formed can significantly reduce wear on the lining and / or copper plates. Furthermore, the inventive concept allows a high stability of the furnace vessel, since a sufficient area of the metal plate remains between the slots through which the copper plates are introduced into the lining.

According to a preferred embodiment, the spacing of the slots arranged side by side corresponds to 1 to 8 times, preferably 2 to 6 times the width of the slots, wherein the thickness of the copper plates preferably at least 70%, preferably at least 90% of the Width of the slots corresponds. These conditions have proven to be particularly advantageous for the formation of a simultaneously effective and stable cooling device.

According to a further preferred embodiment of the invention, the cooling channels arranged on the metal plate extend at least over a range of a vertical length of 80% of the vertical length or extent of the copper plates, preferably over 100% of this length or preferably even over more than 100% of this length ,

According to a further preferred embodiment of the invention, the cooling channels extend between two juxtaposed slots (in horizontal direction) over a range of 40% -100%, preferably 50% -90% of the (horizontally considered) distance between two adjacent slots.

According to a further preferred embodiment of the invention, the copper plates extend (substantially perpendicular to the metal plate and / or at the location of the corresponding slot) over more than 40% of the thickness of the lining in the lining or preferably extend substantially over the entire thickness of the lining. By such an arrangement, the effectiveness of the cooling can be further improved.

According to another preferred embodiment of the invention, the copper plates are in direct or direct contact with the lining. Preferably, at least 50%, preferably at least 75%, of the surface area of the plates is in contact with the lining. This feature also serves to further improve the cooling performance.

According to a further preferred embodiment of the invention, the copper plates also comprise channels through which coolant can flow, which channels are preferably arranged in an end region of the copper plates facing away from the molten metal bath and the slag. Thus, the heat dissipation can be increased by the copper plates. By arranging the cooling channels in an end region of the plates facing away from the slag it is inter alia avoided that water gets into the slag or molten metal, for example in the case of wear or mechanical damage to the plates. In general, the introduction of water or other coolant into the melt or slag can be devastating and result in explosions. In addition, masonry often contains alkali compounds, which under no circumstances should be associated with water.

According to a further preferred embodiment of the invention, the lining has a thickness of 400 mm to 800 mm and preferably a thickness of 450 mm to 650 mm.

According to a further preferred embodiment of the invention, both the lining and the steel plate adjoining the lining are each substantially hollow-cylindrical, so that the hollow-cylindrical lining forms a space for enclosing the molten metal bath and the slag thereon laterally. The rotational symmetry axis of the hollow cylinder is preferably in the vertical direction or can also be described as its longitudinal axis. The circumferential direction of the hollow cylinder is preferably in a plane perpendicular to the axis of rotational symmetry. Alternatively, both the lining and the metal plate each form side walls of a polygonal (especially rectangular) box.

The invention is also directed to a furnace, preferably a reduction furnace, which comprises a cooling device according to one of the preceding embodiments. The oven may preferably be designed as a round oven. That is, the volume formed by the lining and the metal shell or the metal shell for forming a molten metal in a horizontally extending cross-section is substantially round (circular). The advantages of the oven over the prior art are substantially the same as those of the above-mentioned refrigerator.

According to a preferred embodiment, the cooling device forms a lateral boundary of a furnace vessel for receiving a molten metal bath and a liquid slag above it, wherein the copper plates extend in the vertical direction at most over the height of the slag bath. In other words, the copper plates (in the vertical direction) do not extend over an area in which the Molten metal is located. This area of the lining is preferably free of copper plates.

Furthermore, the present invention is also directed to a method for producing a melting furnace or cooling device for such, preferably a furnace or a device according to one of the preceding embodiments. In this case, the method comprises at least one of the following steps: provision of a substantially hollow cylindrical metal plate with slots arranged adjacent to each other in the circumferential direction of the metal plate, which each extend perpendicular to the circumferential direction; hollow cylindrical walling of the inner wall of the hollow cylindrical metal plate; and inserting a copper plate into the slots, respectively. The steps can also be performed in a different order. Furthermore, the term metal plate or metal armor should not be understood as limiting that it must be a one-piece component. For example, the metal plate may also consist of several butt welded together elements.

The method further comprises the step of providing cooling channels on the outer wall of the hollow cylindrical metal plate in an area between the adjacent slots (on the side of the metal plate remote from the melt or slag).

According to a preferred embodiment of the method, the lining takes place in such a way that the copper plates introduced through the slots contact the lining.

According to a further preferred embodiment of the method, the copper plates extend at least over 50% of the thickness of the lining. The cooling channels may be generally perpendicular to the circumferential direction of the hollow cylindrical metal plate extend over at least a range of 80% of the same direction extending length of the slots.

All features of the embodiments described above can be combined with each other or replaced.

Brief description of the figures

Figur 1

eine schematische Seitenansicht einer Außenwandung eines Reduktionsofens mit einem Ausführungsbeispiel einer erfindungsgemäßen Kühleinrichtung;

Figur 2

einen schematischen, horizontalen Teilquerschnitt einer erfindungsgemäßen Kühlvorrichtung bzw. eines Ofens;

Figur 3

einen schematischen, vertikalen Teilquerschnitt einer erfindungsgemäßen Kühlvorrichtung bzw. eines Ofens; und

Figur 4

einen schematischen, vertikalen Teilquerschnitt einer weiteren erfindungsgemäßen Kühlvorrichtung bzw. eines Ofens

The figures of the embodiments will be briefly described below. Further details can be found in the detailed description of the embodiments. Show it:

FIG. 1

a schematic side view of an outer wall of a reduction furnace with an embodiment of a cooling device according to the invention;

FIG. 2

a schematic horizontal partial cross section of a cooling device according to the invention or a furnace;

FIG. 3

a schematic, vertical partial cross section of a cooling device according to the invention or a furnace; and

FIG. 4

a schematic, vertical partial cross section of another cooling device according to the invention or a furnace

Detailed description of the embodiments

The FIG. 1 shows a side view of an embodiment of a cooling device according to the invention. In sections, two copper plates 7 are shown extending substantially perpendicularly to a metal plate or armor 5 (in particular of steel or a steel alloy), which protrude through (longitudinal) slots 13 of the metal plate 5 therethrough. Preferably, each copper plate 7 is attached by fastening means 15 to the metal plate 5 directly or indirectly. The metal plate 5 extends substantially in a vertical direction V. Such a direction may be substantially perpendicular to the melting or slag level of a molten metal M or slag S in a melting furnace. Preferably, the copper plates 7 with cooling channels 11 (in FIG. 1 not shown), which are supplied by inlets 17 and outlets 19 with coolant. However, a coolant may, for example, include water but also be formed by other liquids. Behind the illustrated view of the metal plate 5 is a lining 3, which is in contact with a melt and / or slag S (not shown). Between the adjacent copper plates 7 are preferably cooling channels 9 on one of the melt M or slag S opposite or arranged facing away from the melt M or slag S side of the metal plate 5. These channels 9 may include, for example, metal chambers which are welded to the metal plate 5 or sealingly screwed or riveted thereto. The channels 9 may extend substantially parallel to the copper plates 7 and / or be arranged meandering between the copper plates 7. Via inlets 21 and outlets 23, the channels 9 can be supplied with coolant. As also shown, the cooling channels 9 preferably extend over a majority of the distance A between two adjacent (but spaced apart) copper plates 7. Preferably, the channels also extend at least over half the height (in the vertical direction) of the copper plates 7 or slots 13 or even, as shown, over more than the height of the copper plates 7 or the slots 13. Among other things, on the one hand copper material can be saved by the arrangement shown on the one hand, but on the other hand, an efficient cooling possible. The copper plates 7 may generally be made of any copper alloy.

In the FIG. 2 is a partial cross-sectional view of one of FIG. 1 similar arrangement in the horizontal direction H shown. The copper plates 7 extend in the cross-sectional view, finger-like into the lining 3, which is in contact with the slag S or melt M. The metal plate 5 and the lining 3 may have a curved shape. In particular, the lining 3 and the metal plate 5, a lateral boundary for a molten metal M or slag S a round furnace, z. B. a reduction furnace. In this case, the metal plate 5 and / or the lining 5 is formed as a hollow cylinder. As already in relation to the FIG. 1 described, the copper plates 7 extend from one of the slag S opposite side (back) of the metal plate 5 through the metal plate into the lining 3. Preferably, the lining 3 contacts the copper plates 7. The means for fixing the copper plates 7 may angular elements or Console elements comprise, which protrude substantially perpendicularly from the metal plate 5 on both sides of a copper plate 7, wherein the copper plate 7 is preferably secured by bolts or screws to these elements. In addition, the copper plates 7 preferably comprise cooling channels or bores 11. These can be arranged to improve the operational reliability in a region of the copper plates 7 which does not protrude into the lining 3 or on a side of the metal plate facing away from the melt M or slag S. 5 is located.

In general, the lining 3 and / or the metal plate 5 may each be integrally formed or composed of several elements. Thus, the metal plate 5 may for example consist of a plurality of welded, riveted or bolted (plate-like) elements. The assembly of several elements may be particularly advantageous for large furnace diameters in the order of up to 25 m. For example, the lining 3 may be bricked or cast, as is conventional in the art. Furthermore, a heat-conducting layer, in particular a carbon-containing heat-conducting layer, can generally be present between the lining 3 and the metal plate 5. This can be for example one Thickness of several centimeters. However, such layers are familiar to the person skilled in the art.

The FIG. 3 shows a schematic partial cross-section in the vertical direction V. In addition to the components of the cooling device further elements of a reduction furnace are shown, which are not considered essential for the present invention. In turn, the lining 3, the metal plate 5 lying behind or on a side of the lining 3 facing away from the slag S or melt M, and a copper plate 7 projecting into the lining 3 through an opening 13 in the metal plate 5 are shown. The copper plate 7 preferably extends over at least half the thickness of the lining 3, whereby an effective cooling or heat dissipation is made possible. Furthermore, the copper plate 7 preferably extends over only a region of the slag bath S in the vertical direction V, not over the region of the molten metal bath M. In particular, the slag S can thus be brought into contact with the lining 3 and / or the copper plate 7 in a solid state be, whereby the damage or wear of these elements is reduced by the slag S.

The FIG. 4 disclosed in analogy to the FIG. 3 a schematic partial cross section of a cooling device or a furnace in the vertical direction V, but with the difference that the copper plate 7 extends to further improve the heat dissipation through or over the entire thickness of the lining 3.

Above all, the embodiments described above serve to better understand the invention and should not be understood as limiting. The scope of protection of the present patent application results from the patent claims.

The features of the described embodiments can be combined with each other or exchanged for each other.

Furthermore, the features described can be adapted by the skilled person to existing circumstances or existing requirements.

LIST OF REFERENCE NUMBERS

3

lining

5

metal plate

7

copperplate

9

cooling channels

11

Cooling channel in copper plate

13

Slots in metal plate

15

Holder of the copper plate

17

Coolant inlet of the copper plate

19

Coolant outlet of the copper plate

21

Coolant inlet of the cooling channel

23

Coolant outlet of the cooling channel

A

Distance between two adjacent slots

H

horizontal direction

M

molten metal

S

Melt / slag

V

Vertical direction / longitudinal direction of the hollow cylinder

Claims (14)

1. A cooling device for a smelting furnace, particularly for the cooling of a liquid slag (S) in a reduction furnace, comprising:

   a lining (3) for lateral screening of a liquid metal melt bath (M) and a liquid slag (S) present thereon;

   a metal plate (5) arranged on a side of the lining (3) opposite the metal melt bath (M) and the slag (S); and

   a plurality of copper plates (7) for cooling the lining (3), wherein

   the metal plate (5) has a plurality of substantially vertically oriented slots (13) arranged adjacent to one another, wherein a respective copper plate (7) extends through at least some of the slots (13) substantially perpendicularly to the metal plate (5) into the lining (3),

   characterised in that

   the device further comprises cooling channels (9), which can be flowed through by coolant and which are respectively arranged between two mutually adjacent slots (13) and the copper plates (7), which extend through these slots (13), on the side of the metal plate (5) remote from the metal melt bath (M) and the slag (S).
2. Cooling device according to claim 1, wherein the spacing (A) of the slots (13) which are adjacent to one another corresponds with 1 times to 8 times, preferably 2 times to 6 times, the width of the slots (13) and/or the thickness of the copper plates (7) respectively corresponds with at least 70%, preferably at least 90%, of the width of the slots (13).
3. Cooling device according to claim 1 or 2, wherein the cooling channels (9) arranged on the metal plate (5) extend at least over a region of a vertical length of 80% of the vertical length of the copper plates (7), preferably over 100% of this length, or preferably even over more than 100% of this length.
4. Cooling device according to any one of the preceding claims, wherein the cooling channels (9) extend between two mutually adjacent slots (13) in horizontal direction (H) over a region of 40% to 100, preferably from 50% to 90%, of the spacing between the two mutually adjacent slots (13).
5. Cooling device according to any one of the preceding claims, wherein the copper plates (7) extend into the lining (3) over more than 40% of the thickness of the lining (3) or preferably extend substantially over the entire thickness of the lining (3).
6. Cooling device according to any one of the preceding claims, wherein the copper plates (7) have direct contact with the lining (3).
7. Cooling device according to any one of the preceding claims, wherein the copper plates (7) similarly comprise channels (11), which can be flowed through by coolant and which are preferably arranged in an end region of the copper plates (7) remote from the metal melt bath (M) and the slag (S).
8. Cooling device according to any one of the preceding claims, wherein the lining (3) has a thickness of 400 millimetres to 800 millimetres and preferably a thickness of 450 millimetres to 650 millimetres.
9. Cooling device according to any one of the preceding claims, wherein the lining (3) and the steel plate (5) adjoining the lining (3) are each of substantially hollow-cylindrical construction so that a space for lateral enclosure of a metal melt bath (M) and a slag (S) present thereon is formed in the interior of the lining (3) of hollow-cylindrical form.
10. A furnace, preferably a reduction furnace, comprising the cooling device according to any one of the preceding claims.
11. Furnace according to claim 10, wherein the cooling device forms a lateral boundary of a furnace vessel for receiving a metal melt bath (M) and a liquid slag (S) disposed thereabove and the copper plates (7) extend in substantially vertical direction (V) at most over the height of the slag (S).
12. A method of producing a smelting furnace or a cooling device for such, preferably a furnace or a device according to a respective one of the preceding claims, comprising the following steps:

    providing a metal plate (5) of substantially hollow-cylindrical form with slots (13) which are arranged adjacent to one another in the circumferential direction of the metal plate (5) and which each extend perpendicularly to the circumferential direction;

    lining-out, in hollow-cylindrical form, the inner wall of the metal plate (5) of hollow-cylindrical form;

    introducing a respective copper plate (7) into each of the slots (13); and

    mounting cooling channels (9) on the outer wall of the metal plate (5) of hollow-cylindrical shape in a region between the mutually adjacent slots (13).
13. Method according to claim 12, wherein the lining (3) is carried out in such a manner that the copper plates (7) introduced through the slots (13) contact the lining (3) and/or the lining (3) has slots (13) for introduction of the copper plates (7).
14. Method according to claim 12 or 13, wherein the copper plates (7) extend over at least 50% of the thickness of the lining (3) and/or the cooling channels (9) extend perpendicularly to the circumferential direction of the metal plate (5) of hollow-cylindrical form over at least a region, of 80% of the length of the slots (13) running in the same direction.

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