EP1155154A1

EP1155154A1 - Blow form for shaft furnaces, especially blast furnaces or hot-blast cupola furnaces

Info

Publication number: EP1155154A1
Application number: EP00910497A
Authority: EP
Inventors: Kurt Peter Stricker; Jürgen WITTE; Rainer Altland
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1999-02-05
Filing date: 2000-01-20
Publication date: 2001-11-21
Anticipated expiration: 2020-01-20
Also published as: AU3270900A; JP2002544374A; BR0008037A; US20010052311A1; WO2000046410A1; RU2221975C2; US6446565B2; EP1155154B1

Abstract

The invention relates to a blow form for shaft furnaces, especially blast furnaces or hot-blast cupola furnaces, comprised of a conical hollow body with an inner and outer casing and of a frontal part which connects the same. The hot air to be supplied to the shaft furnace is fed through the inner casing of the hollow body and, during operation, a coolant stream flows though the cavity of the hollow body formed between the inner and outer casings, whereby the cavity is subdivided into a pre-chamber situated in the area of the frontal part and into a main chamber which is connected to said pre-chamber. The pre-chamber and main chamber are completely separated from one another using hydraulics and each comprises a separate coolant circuit with its own connections. The outer casing (2) is formed by a one-piece base body (1) which, when viewing the cross-section, is symmetric with regard to the vertical axis. Said base body merges into the frontal part (5) on the frontal side without interruption, and the inner casing (3) is formed by a conical welded part (4). The channels (11, 13) which supply and carry away the coolant to/from the frontal part (5) and which are situated in a 12 o'clock position of the blow form and with regard to the longitudinal axis of the blow form are arranged outside the original cross-section of the main chamber (10) of the blow form. The welded part (4) forms the inner covering of the undulated cooling channel (15) of the main chamber (10).

Description

Blow mold for shaft furnaces, especially blast furnaces or hot-wind cupola furnaces

description

The invention relates to a blow mold for shaft furnaces, in particular blast furnaces or hot-wind cupola furnaces, according to the preamble of patent claim 1.

Such water-cooled blow molds, which are largely made of copper or a copper alloy, are widely used to supply the

Hot wind used to ensure effective operation of the shaft furnace. In the case of a blast furnace, the temperature of the hot mixing wind is in the range of approx. 700 to over 1300 degrees Celsius at pressures between 2.5 and 5.5 bar. Not only is the inner jacket of the blow mold, and in particular the front part, heavily stressed, but also as the wear progresses

Refractory brick lining of the shaft furnace and thus exposing the front area of the blow mold increasingly the jacket area through melting phases such. B. pig iron, slag, partially reduced waste and zinc, and by abrasion with coke and / or wind. In order to achieve a sufficient service life under these extreme stresses, it is necessary to keep the blow mold at tolerable temperatures by intensive cooling by means of a coolant, usually cooling water, which is passed through it. It is also necessary to minimize the surface wear of the blow mold due to corrosive effects of melting phases and abrasion by taking suitable measures.

A blow mold for shaft furnaces is known from DE-OS 35 05 968. In this construction, a double-walled hollow body consisting of an inner and an outer jacket and a front part connected to them is attached to a base part. The cavity formed between the inner and outer jacket is divided into a front wall and a front wall by an intermediate wall arranged in the front part area Subsequent main chamber divided. A supply line for the coolant arranged in the base part extends as a tube through the main chamber and the intermediate wall into the prechamber. The intermediate wall has a plurality of openings so that the coolant can flow back from the antechamber into the main chamber. From there it flows through openings arranged in the base part into an annular chamber, which is connected to a

Return connection is provided. The disadvantage of this design is that the blow mold is cooled with only one cooling circuit system and, in the event of cooling failure or the occurrence of leaks in the blow mold and the throttling of the cooling water quantity that is therefore inevitably required, it is stressed so quickly that it can be used in a short time is destroyed with all resulting from it

Consequences and dangers. Another disadvantage is the fact that the cooling water is not routed at several points, so that turbulence occurs which favors the formation of vapor bubbles and thus the heat dissipation at these points is greatly reduced. In extreme cases, this can lead to local melting and thus destruction of the blow mold.

A further development of the blow mold is known from US 2,735,409. In this known embodiment, the hollow body is divided into a prechamber located in the front part area and an adjoining main chamber, the prechamber and main chamber being completely hydraulically separated from one another and each having a separate coolant circuit with its own connections. The coolant circuit of the main chamber consists of a helically tightly wound tube forming the outer jacket, while the coolant circuit of the prechamber consists of two parallel straight tubes which open into the U-shaped annular channel of the front part. In a first embodiment, the inner jacket is designed as a smooth conical tube, the two straight tubes of the prechamber being arranged between the inner and outer jacket. In a second embodiment, the inner jacket is also formed from a helically tightly wound tube. The front part is manufactured as a separate part and either via anchors with the rear connection part or directly via one

The weld seam is connected on the face to the inner and outer jacket. Disadvantages of this known construction are the cooling channels in the main chamber area, which are very small in design and have an unfavorable transverse shape (rectangle), and the very small cross sections in the supply lines to the antechamber due to the design. The related to a reduction in cross-section and related to an increasing Deviation from the round cross-sectional shape, a disproportionate decrease in the cooling medium volume flow both in the antechamber and in the main chamber results in a correspondingly clear deterioration in the cooling effect. Another disadvantage is that, according to the description of the above-mentioned document, the cross section of the prechamber cooling duct should be as small as that of the

Main chamber cooling duct. From the cross-sectional shape, this results in a rectangular prechamber cooling duct with very unfavorable aspect ratios and a poor cooling effect resulting therefrom. The opening of the inlet channel into the pre-chamber cooling channel is also disadvantageous, since this means a high hydraulic resistance in this cooling circuit with the resulting lower cooling medium volume flow or lower cooling medium speed in the pre-chamber and the resulting poor cooling effect. The overall construction is very complex to manufacture and has a large number of critical sealing parts, some of which are undissolved. The problem of the external attack of the main chamber of the known blow mold by dripping melting phases in the blast furnace is also unsolved.

The object of this invention is to provide a blow mold of the type mentioned above, which ensures a disproportionately long service life and thus low operating costs as well as a favorable operating behavior of the shaft furnace equipped with it, at a reasonable cost for the production by cooling which is extremely effective in the thermally highly stressed front part area, without significantly changing the available cooling water quantities and differential pressures. Another task is to prevent the blow mold from dripping as far as possible by means of a favorable geometric design

To protect the melting phases in the shaft furnace and to provide the main (rear) chamber, which is generally not thermally so highly stressed, with extremely effective cooling, without the cooling water quantities and differential pressures available, as well as the operating costs for the cooling water that are directly connected with this to change.

This object is achieved on the basis of the preamble in conjunction with the characterizing features of patent claim 1. Advantageous further developments are the subject of subclaims. The essence of the invention is the formation of the outer jacket by a one-piece body, seen in cross-section vertically symmetrically, which merges into the front part without a shoulder. The inner jacket is formed by a conical welded part, which forms the inner cover of the helical cooling channel of the main chamber. Another important feature is the arrangement of the channels supplying the front part with cooling medium in the 12 o'clock position of the blow mold, with reference to the longitudinal axis of the blow mold, outside the original cross section of the main chamber. The proposed arrangement of the cooling channels of the prechamber takes into account the different loads on the blow mold seen in the circumferential direction. The blow mold in the 12 o'clock position has been proven to be more heavily loaded than in the side areas. Intensive cooling of this stressed area significantly increases the service life of the bias shape. The coolant circuit of the main chamber can optionally be designed as a two-course helical cooling channel or can be provided with a helical cooling channel and a straight cooling channel in the blow mold's 6 o'clock position. The straight cooling channel, which is parallel to the longitudinal axis of the blow mold and provided with no ribs, is arranged outside the original cross section of the main chamber of the blow mold with respect to the longitudinal axis of the blow mold, the connections for the flow and return being adjacent to the connections of the antechamber at 12 o'clock. Position range. With the arrangement of the straight cooling duct at 6 o'clock

The position of the blow mold takes into account the different loads on the blow mold in the circumferential direction. In addition to the 12 o'clock position, the blow mold is also more heavily loaded in the 6 o'clock position than in the side areas. Due to the intensive cooling of this area, the service life of the blow mold is further increased.

As already mentioned, the proposal provides for the inlet and return channels for the antechamber and the return channel of the main chamber to be removed from the area of the original cross section of the main chamber of the blow mold, and in each case in a radial direction outside the main chamber, based on the longitudinal axis of the blow mold. This ensures that none in the cooling channel of the main chamber

Cross-sectional constrictions arise through inlet and return channels. This results in optimal fluidic conditions with the highest possible coolant speeds in the main chamber. Furthermore, all the channels mentioned have a virtually constant cross section over the length and the required cross-sectional changes in the connection area as well as the small-scale changes in direction are rounded off and without jumps.

With these measures, flow rates for the coolant are achieved in the main chamber, which are at least twice as high as in the known designs. This is achieved by avoiding dead zones, turbulence points, throttling points, dust areas as well as by the optimal design options for the cooling duct cross-sectional shapes (round, trapezoidal) and the cross-sectional size of the individual duct sections. The optimal design of the inlet and return channel for the prechamber leads with the same

Differential pressure also in the antechamber to significantly higher flow rates. If you continue to ensure that the desired high flow velocities are achieved through a balanced ratio of pump output and channel cross-section, this also largely suppresses the formation of vapor bubbles. The aim is also at low available

Differential pressure of, for example, 2 bar for the cooling of the highly loaded antechamber a flow rate of> 10m / sec and for the main chamber of 6m / sec. The proposed design of the blow mold is suitable for antechambers with only one ring channel as well as for longer antechambers with a helical channel .

However, as already mentioned at the beginning, the blow mold is not only subjected to thermal stress, but also additionally chemically and mechanically; especially when the wear of the refractory lining of the shaft furnace has reached a certain level. It is suggested that the cross section of the blow mold at 12 o'clock

Form the location area as a roof. This has the advantage that substances falling or dripping on the blow mold can slide off or flow off more easily. This training is intended in particular to reduce the undesired contacting of liquid zinc, pig iron or slag with the blow mold made of copper or copper alloy. As is known, zinc reacts with copper, so that the copper wall is chemically reduced.

In the drawing, the blow mold designed according to the invention is explained in more detail using an exemplary embodiment. Show it: 1 shows a longitudinal section in the direction AA in Figure 2 through a blow mold designed according to the invention

FIG. 2 shows a side view in the direction X of FIG. 1

3 shows a section in the direction B-B in Figure 1

The blow mold designed according to the invention consists of a base body 1 forming the outer jacket 2 and a weld-in part 4 forming the inner jacket 3. The hollow body forming between the outer jacket 2 and the inner jacket 3 is closed off at the front by a thermally highly stressed front part 5. On the input side, the base body has a double-conical inlet section 6, into which the nozzle tip of a nozzle assembly (not shown here) is inserted. In the upper part of the inner casing 3, the refractory layer 7 arranged on the inner casing 3 is indicated. The face area of the

Front part 5 is provided with armor 8 in order to protect the front part 5 from mechanical damage and wear. As is known, the hollow body charged with coolant is divided into a prechamber 9 and a main chamber 10. Both chambers 9, 10 are hydraulically completely separated from one another and connected to separate cooling circuits.

According to the position of the section in A-A in FIG. 2, the inlet channel 11 for the prechamber 9 can be seen in FIG. 1 in the upper part of the blow mold. On the inlet side, the inlet channel 11 is provided with a connection 12 in the form of a threaded section, into which an inlet pipe, not shown here, can be screwed. The

Inlet channel 1 1 then merges into prechamber 9, which is formed by an annular channel 22 lying transverse to inlet channel 11. Instead of an annular channel, it is also possible to arrange a helically shaped channel having a plurality of revolutions.

It can be seen in FIG. 2 that in the region of the 12 o'clock position of the blow mold, the return channel 13 for the prechamber 9 is arranged parallel to the inlet channel 11. It is also provided with a connection 14 arranged on the end face in the form of a threaded section, into which a drain pipe, not shown here, can be screwed. The location of the two channels 1 1, 13 is particularly good according to the

Recognition in Figure 3. So that the coolant is also efficiently guided in terms of flow technology in the main chamber 10, the latter has a helical cooling channel 15. The inside of this cooling channel 15 is covered by the inner jacket 4. The coolant is supplied or removed to the main chamber 10 in the 1 o'clock or 1 o'clock position area, adjacent to the connections 12, 14 for the prechamber 9 . In the

Seen clockwise behind the inlet connection 18 arranged in the 1 o'clock area, the coolant is guided downwards into the 6 o'clock position through a semicircular channel 20 (shown with dashed lines in FIG. 2) in the double-conical inlet section 6 and enters here the helical cooling duct 15. After passing through the helical cooling channel 15, the cooling medium occurs directly in front of the

Antechamber 9 into a return channel 16, which is also located at 6 o'clock, which lies below the helical cooling channel 15 and guides the cooling medium back into the double-conical inlet section 6. In the double-conical inlet section 6, the cooling medium is again in a semicircular channel 21 (in Fig 2 shown with dashed lines) in the 1 1 o'clock position up to the drain connection

17 out. On the face side, the two cooling channels 15, 16 for the main chamber 10 are also provided with a threaded section 17, 18 into which the inlet and outlet pipes are screwed. The inlet and return connections 12, 14, 17, 18 for both the prechamber and the main chamber are interchangeable without the desired effect of an intensive cooling effect being changed.

According to the invention, the cooling ducts 11, 13 for the prechamber 9 or the annular duct 22 are approximately the same in cross section, but smaller than the cross sections F1, F2 of the cooling ducts 15, 16 of the main chamber 10. That means:

F4 = F5 <F1 = F2.

The cross-sectional transitions and the small-scale changes in direction of the channels are greatly rounded, so that no swirling points or dead zones can arise.

The additional chemical and mechanical stress that occurs on the blow mold is strongly influenced by the geometric shape. The hollow body is conically tapered in the direction of the shaft furnace, a half cone angle in the range of 12-14 ° being found to be favorable. In the same According to the invention, the roof-like configuration 19 of the 12 o'clock position area of the blow mold can also be seen acting in the direction. Substances of the shaft furnace or the feed falling or dripping onto the blow mold can thus easily slip or flow off sideways and towards the center of the shaft furnace.

Claims

claims

1. Blow mold for shaft furnaces, in particular blast furnaces or hot-wind cupola furnaces, consisting of a conically shaped hollow body with an inner and an outer jacket and a front part connecting them, by means of the latter

Inner jacket of the hot wind to be fed to the shaft furnace and the cavity formed between the inner and outer jacket is flowed through during operation by a coolant flow, the cavity being subdivided into a prechamber located in the front part area and an adjoining main chamber, which are hydraulically completely separated from one another each have a separate coolant circuit with their own connections, the coolant circuit for the prechamber consisting of two channels arranged parallel to the longitudinal axis of the blow mold, forming the flow and the return and having an almost constant cross-section, which open into an annular channel arranged transversely to the channels in the front part and the coolant circuit of the main chamber (10) is provided with a helical cooling channel which, when viewed over its length, has an almost constant cross section, characterized in that the outer jacket (2) provides Det is formed by a one-piece, axially symmetrical basic body (1) in cross-section, which merges into the front part (5) without a front and the inner jacket (3) is formed by a conical welded part (4) and the cooling medium to the front part (5) supply and discharge channels (11, 13) in the 12 o'clock position of the blow mold and in relation to the longitudinal axis of the blow mold are arranged outside the original cross section of the main chamber (10) of the blow mold and the weld-in part (4) the inner cover of the helically shaped Cooling channel (15) of the main chamber (10) forms.

2. Blow mold according to claim 1, characterized in that the helical cooling channel of the main chamber (10) has two passages, one helical cooling channel forming the flow and the other helical cooling channel forming the return and both helical

Cooling channels are connected to each other by a 180 ° deflection.

3. Blow mold according to claim 1, characterized in that the coolant circuit of the main chamber (10) in the 6 o'clock position of the blow mold has a straight cooling channel (16) and the straight cooling channel (16) lying parallel to the longitudinal axis of the mold and provided without ribs is arranged on the longitudinal axis of the blow mold outside the original cross section of the main chamber (10) of the blow mold, the connections (17, 18) for the forward and return flow being adjacent to the connections

(12, 14) of the prechamber (9) are arranged in the 12 o'clock position area.

4. Blow mold according to one of claims 1-3, characterized in that the cross-sectional shape of the channel lying in the longitudinal axis of the

Antechamber (9) is circular and that of the helical channel (15) of the main chamber (10) is approximately trapezoidal with rounded corners.

5. Blow mold according to one of claims 1-4, characterized in that for all channels (1 1, 13, 15, 16) of the prechamber (9) and the main chamber (10) cross-section changes in the connection area and the small-wheel direction changes are rounded and without jump points.

6. Blow mold according to claim 3, characterized in that two semi-circular channels (20, 21) connected to the connections (17, 18) are arranged in the double-conical inlet section (6), which lead down to the 6 o'clock position and are hydraulically completely separated from each other in both the 12 o'clock and the 6 o'clock position and establish the connection to the helical cooling duct (15) of the main chamber (10), with the helical cooling duct (15) at the front end directly at the Partition to the antechamber (9) of the straight cooling duct (16) adjoins the one below the helical cooling duct (15)

The 6 o'clock position area is located and in turn ends in the double-conical inlet section (6).

7. Blow mold according to one of claims 1-6, characterized in that the cross sections (F4) of the supply and discharge channel (11, 13) for the prechamber (9) and the cross section (F5) of the ring channel (22) in the Antechamber (9) is almost the same size, but smaller than the cross sections (F1, F2) of the cooling channels (15, 16) of the main chamber (10).

8. Blow mold according to one of claims 1 and 3-7, characterized in that the straight cooling channel (16) of the main chamber (10) has a cross section (F1) which is almost the same size as that of the helical cooling channel (15) Main chamber (10).

9. Blow mold according to claims 7 and 8, characterized in that the cross sections (F4, F5) of the cooling channels (11, 13, 22) of the prechamber (9) compared to the cross sections (F1, F2) of the cooling channels (15, 16) the

Main chamber (10) are up to 35% lower.

10. Blow mold according to claims 7-9, characterized in that with approximately the same pump output for the coolant supply of the pre-chamber (9) and main chamber (10), the flow rate in the cooling channels (15, 16) of the main chamber (10) is at least 60%. the flow rate in the

Cooling channels (11, 13, 22) of the prechamber (9).

1 1. Blow mold according to claim 10, characterized in that at a coolant differential pressure on the blow mold of 2 bar

Speed of the coolant in the cooling channels (11, 13, 22) of the prechamber (9) is at least 10 m / sec and in the cooling channels (15, 16) of the main chamber (10) is at least 6 m / sec.

12. Blow mold according to one of claims 1 - 1 1, characterized in that, seen in cross section, the blow mold in the 12 o'clock position is designed as a roof and in the 6 o'clock position as a bulge and in the roof-like area the cooling channels ( 11, 13) of the antechamber (9) and in the bulging area of the straight cooling channel (16)

Main chamber (10) is arranged.