EP1391523B1 - Twin-furnaces unit for steel production - Google Patents

Abstract

Double oven arrangement has a tilting stage (29) arranged between two tilting oven stages (3) with a tilting, lifting and lowering electrode support device (16) formed on the tilting stage. The tilting stage can be tilted depending on the tilting movement of an oven stage for an oven vessel (4).

Description

The invention relates to a double furnace plant for the production of steel materials by alternately charging iron-containing feedstocks, oxygen inflation and arc melting respectively by means of a furnace A and a furnace B, which are each arranged on a tiltable furnace platform and with a between the furnaces A and B arranged pivot column to which a raisable and lowerable electrode support device is attached and with a pivoting device for at least one oxygen Aufblaslanze.

Such a double electric arc furnace plant is known from DE 44 34 369 and EP 0 717 115 B1. It can be assumed that the two furnace vessels are each arranged on a separate tilting platform. Between these two tilting stages, the pivotable, raisable and lowerable electrode support device is provided on the fixed oven platform. As a result, the scrap can be melted alternately in two furnace vessels. Accordingly, while electrical energy is introduced into the melt in a furnace vessel by means of the pivotable, liftable and lowerable electrode support arms, the tapping can take place at the second furnace vessel and scrap can be introduced for the next melt. In the system known from DE 44 34 369 two ovens a common non-tilting lance device is assigned.

In a so-called CONARC double oven plant (CONARC is a registered trademark of Messrs. SMS Demag AG), during the use of the electrodes in the first vessel for melting in the second vessel, an oxygen lance, e.g. in the form of a top lance, are used.

In this known arrangement has proved to be less favorable that the electrode support device can not be tilted simultaneously with the respective tilting stage and the respective furnace vessel. If the use of the electrodes in a tilted position of the furnace vessel is appropriate, it lacks the necessary conditions. In general, the leadthrough must have an oversized opening. It should also be noted that the passage of the electrodes through the furnace lid requires the least possible path. A small way is generally achieved through the scheduling of roll and curve weighing. However, the use of such cradles is associated with high technical complexity. Furthermore, large forces occur on the piston-cylinder unit during tilting of the bricked and charged furnace vessel. Furthermore, roller and curve weighing are subject to high wear. The replacement of rollers and rails is also associated with high costs and long downtime of the production plant. With the help of all these measures, the achievable tilt angle can only be set at approx. ± 3 °.

Double oven plants are still known (for example DE 4138120 A1) which, by means of a lifting and slewing mechanism, respectively attach the electrode support device to the furnace vessel to be tilted. This is due to the lifting and slewing a high technical effort required. This construction has also proven to be very prone to failure in practice.

The invention has for its object to make the use of the electrodes on a double oven without restriction from the furnace mechanics.

The above object is achieved in the above-mentioned double oven system according to the invention that between the two tiltable furnace platforms, a third tilting stage is provided on which the pivotable, raisable or lowerable electrode support device is arranged and that the third tilting stage in the immediate dependence of Tilting each one of the oven platforms for a furnace vessel is tilted and that the third tilting platform with the pivotable, raised or lowered electric en-carrying device is associated with its own tilting drive with a control device. As a result, it is possible to work more undisturbed with the electrodes even with a tilted furnace vessel, which is of great advantage, particularly in the process steps operated in the double furnace or CONARC process. As a result, the respective oven platform and the third tilting stage can be actuated absolutely simultaneously. The use of such a third tilting stage is possible, at least for a DC and AC double oven. Special advantages arise for different process steps, such as. Pig iron charging, dephosphorization, slag reduction u. like.

One embodiment is that the third tilting platform with the pivotable, raisable and lowerable electrode support device can be locked alternately with the respective oven platform to be tilted. This results in absolutely dependent tilting movements between the furnace platform of a furnace vessel and the third tilting platform.

Furthermore, there is for the above design of the proposal that the control device of its own tilting drive is formed from a synchronization device which can be connected to the control device of the respective furnace platform to be tilted.

Another advantageous design method is further provided by the fact that the own tilting drive is formed from an arranged within the foundation piston-cylinder unit. The required space between the oven platforms for the oven vessels has not been used.

Another measure for securing the different tilting sequences is achieved in that, when the synchronizing device is connected to the respective control device of a furnace platform to be tilted, a connection to the respective other control device for the respective other furnace platform is blocked.

A development of the invention provides that in each of the furnace A and B associated lid pivoting device is integrated in each case an oxygen lance, wherein the combination pivoting device for lid and lance is arranged on the tiltable oven platform.

Although an additional O ₂ lance with Lanzenführung and O ₂ supply line must be provided for this layout of the plant, the advantages are that for the oxygen lances no separate pivoting devices is necessary, but integrated the lances in the existing Deckelschwenkvorrichtungen become. At the same time and this is a particular advantage, the O ₂ lances are tiltable together with the swiveling devices via the oven platform together with the ovens. Thus, the oven can tilt with retracted O ₂ lance. In addition, the system is less prone to failure of an O ₂ lance, as the operation in the other furnace can be continued.

The inventive system with tiltable electrode support device and tiltable Deckelschwenkvorrichtungen with integrated oxygen lances is further developed advantageous that the known elaborate Deckelhubwerk is replaced by a support arm construction with hoist. In detail, the Cover pivoting device next to the support arm for the oxygen lance at least one further support arm, preferably two support arms, for the furnace cover and the O ₂ lance cover on. These support arms are arranged at one end on a pivoting column. At the other end, which extends over the lid, hydraulic lifting cylinders are arranged, which are in communication with the respective upper lid side. About this lifting cylinder, the lid can be placed on the respective oven or removed again. These lifting cylinders are arranged distributed over the support arms.

Furthermore, the system is further developed by an advantageous exhaust system. From the basic idea, a common exhaust pipe per furnace now takes over the removal of the hot gases and dusts during the melting as well as the blowing process. This exhaust pipe is designed in several parts. A pipe part, which is arranged directly on the furnace cover, is designed as a pipe socket detachably formed with respect to the remaining exhaust pipe and pivotable in the decoupled state together with the furnace cover. When the furnace lid is pivoted onto the furnace, this pipe socket is aligned flush with the rest of the exhaust pipe, wherein the adjoining the pipe socket exhaust pipe is tilted together with the furnace platform. This has the advantage that the furnace vessel can be opened for Chrargieren in a less expensive way and only a part of the elbow must be pivoted.

Overall, a system results, which shows a less costly design of the Deckelhubwerks and Absaugkrümmerhubvorrichtung compared to the prior art, which must be raised. Tilting through the furnace platform is less costly than tilting by means of a roller cradle. In addition, the cooling water supply to the furnace lid can be made much more reliable and cheaper, because a favorable arrangement of the cooling water pipes to the furnace lid is possible. The manufacturing costs of the entire system are reduced overall, while the reliability and the flexibility of the plant can be increased. It also improves the possibility of scheduling the plant concept in existing halls.

In the drawings, embodiments of the invention are shown, which are explained in more detail below.

Fig. 1

einen Aufriss einer Doppelofen-Anlage,

Fig. 2

die zu Fig. 1 gehörende Draufsicht auf die Doppelofen-Anlage, mit einem vom Ofengefäß B weggeschwenkten Ofendeckel,

Fig. 3

die dritte Kippbühne in Normalstellung in der Seitenansicht,

Fig. 4

die dritte Kippbühne in der nach hinten gekippten Stellung,

Fig. 5

die dritte Kippbühne in einer nach vorne gekippten Stellung,

Fig. 6

eine zu Fig. 1 gehörende Draufsicht auf die Doppelofen-Anlage in einer anderen Betriebsposition und

Fig. 7

eine Draufsicht auf die Elektroden-Tragvorrichtung mit Nachsetzvorrichtung.

Show it:

Fig. 1

an elevation of a double oven plant,

Fig. 2

1 belonging to the plan view of the double oven plant, with a weggeschwenkten from the furnace vessel B furnace lid,

Fig. 3

the third tilting stage in normal position in side view,

Fig. 4

the third tilting stage in the tilted back position,

Fig. 5

the third tilting stage in a forward tilted position,

Fig. 6

a belonging to Fig. 1 plan view of the double oven plant in a different operating position and

Fig. 7

a plan view of the electrode support device with Nachsetzvorrichtung.

On foundations 1 for a furnace A and a same furnace B of an electric arc double furnace arrangement by means of a substructure 2 each have a tiltable furnace platform 3 for each furnace vessel 4 with a furnace cover 5 is arranged (see Fig. 1). Electrodes 6 are supplied by a furnace transformer 7 (see Fig. 2) via a high-current connection 8 through a transformer house wall 9 by means of high current cables 10. The electrodes 6 can be pivoted by means of a pivoting column 11 over the furnace A or the furnace B.

For this purpose, the electrodes 6 are brought into a drawn in Fig. 1 upper position by a lifting column 15 in the pivoting column 11. During this time, this O ₂ lance 13 a is located above the furnace B by means of a pivoting device 12 for the oxygen blowing lance 13 a, likewise on the furnace platform 3.

The electrodes 6 are used by means of the lifting column 15 with a column guide and the electrode support device 16 in height to control the energy supplied. Then support arms 17 and 14 are provided for an electrode inner cover 18 and a similar inner cover 21 for the oxygen Aufblaslanzen 13 a and b. The electrode inner cover 18 is height adjustable by means of lifting cylinders 19 (see Fig. 2). In addition, an electrode adder 20 is provided. The electrode inner cover 18 is held by means of the support arms 17.

To the exhaust pipe 23 connected to the tilting stage 3, a stationary exhaust pipe 24 with a secondary combustion chamber 25 is to be connected in the pivoted-in position. From the furnace B, the exhaust gases are removed by means of an exhaust port 26. (The furnace cover 21 is swung out in Fig. 2). The exhaust pipes 23, 24 and the exhaust port 26 are connected together. Between the individual components are gaps that allow corresponding furnace movements. The gap between tube 23 and 24 is in particular manually adjustable. The gap between the pipe 24 and the exhaust pipe 26 is adjustable by a sliding sleeve. By changing the air gap, the amount of suction from the furnace and the pressure in the furnace vessel is influenced and sucked for the post-combustion (and cooling) necessary amount of false air. The lance inner cover 21 can be adjusted by means of a lifting cylinder 33 in height.

Between the furnace platforms 3 of the furnaces A and B, a third tilting stage 29 is arranged, on which the pivoting stage 11 and the electrode-Nachsetzvorrichtung 20 are located. On the third tilting platform 29 is located on the pivoting column 11, the pivotable, raisable and lowerable electrode support device 16 at the other end to the electrode-Nachsetzvorrichtung 20. This third tilting platform 29 is alternately locked according to a first embodiment with each to be tilted furnace platform 3. A second embodiment provides for the third tilting platform 29 its own tilting drive 30 (see FIG. which consists in the embodiment of a piston-cylinder unit 31 which is mounted within the foundation 1.

The third tilting platform 29 is in accordance with FIG. 3 in the normal position, in Fig. 4 in the forward inclined position and in Fig. 5 in one of the respective furnace and Chargierlage dependent, rearwardly inclined position.

From the two FIGS. 2 and 6, the arrangement of the respective pivoting devices 12 for the furnace lid 5 and the O ₂ inner lid 21 with integrated oxygen lance 13 a, b becomes clear. The combination pivoting device 12, in addition to the function of Deckelverschwenkens also has the function to bring the lance for blowing oxygen 13a, b to the furnace center. The O ₂ -Lanzenanlage is not on the fixed furnace stage, but is integrated in the turret for the cover pan, which is arranged on the tiltable furnace platform. 3 In detail, the pivoting device 12 consists of an inner central support arm 27, at the top of an O ₂ lance 13 a, b is mounted, which is supplied via an oxygen line through the support arm. The O ₂ lance 13 a, b is carried by the support arm 27, which is connected to a guide column and guided in guide rollers. The lifting movement of support arm 27 and O ₂ lance 13 a, b via a hydraulic cylinder installed in the guide column.

The pivoting device 12 further comprises two support arms 14 of the cover structure which extend over the furnace cover 5, first parallel to the central lance support arm 27, and then, when they have reached the edge of the O ₂ inner cover 21, V -Disteally diverge. In this way, the support arms 14 extend over both the furnace lid and the O ₂ lance inner lid.

The support arms 27 and 14 are pivotally mounted by means of a rotary column with a roller bearing, wherein the support arm for the lance 27 and the supporting structure for the cover are pivoted together.

In comparison to conventional systems, the winch control of the oxygen lance is replaced by the control by means of a support arm, guide rollers and hydraulic cylinders. By the lances 13a, b are assigned to the pivoting devices 12, the oven platform is free on the door side. This improves the view from the control room on the furnace and on the electrode-Nachsetzvorrichtung 20. The scrap basket passage and the vessel transport through the O ₂ lance system are not hindered. When laying out the width of the hall when building a new system, the pivoting of the O ₂ lance is not to be considered.

Along the support arms 14 lifting cylinder 22, 33 are arranged and that three for the furnace lid 5 and four for the lance inner lid 21. They are each arranged according to the lid edge. The lid or the lid are pivoted about the oven and then moved over the lifting cylinder 22, 33 by the movement of the respective piston rod in a Verschließposition down. The lifting linkage of the lifting cylinder 22 for the furnace cover 5 is decoupled in the lowered position of the cover 5, so that pivoting of the pivoting device 12 with the support arm 27 and the lance 13 and the support arm 28 with lance cover 21 at a resting on the furnace vessel 4 furnace lid 5 possible is.

With reference to FIGS. 2 and 6, different process states of the Conarc process, in particular for the production of carbon steels and stainless steels, such as stainless steel, are shown. According to FIG. 6, the blowing process takes place in furnace A, while at the same time the melting process with inserted electrodes 6 takes place in furnace B. For the blowing process, the pivoting device 12 is above the furnace A. pivoted. With her or the support structure (14) for the lid 5 and the support arm 27 for the lance 13b of the furnace cover 5 with exhaust port 26, the O ₂ lance inner cover 21 and the oxygen lance 13b pivoted to the middle of the furnace.

During the melting process, the furnace lid 5 is likewise located with the waste gas nozzle 26 on the furnace vessel 4 (furnace B in FIG. 6). With the pivoting device 12, the lance 13 a and the lance inner cover 21 are swung out. The electrode arm is pivoted to middle furnace B.

The electrode pivoting device is likewise composed of a support arm construction, wherein the electrode inner cover 18 can be arranged in the cover heart via lifting cylinders 19 positioned along the support arms 17. Within the substantially rectangular designed support arm construction three electrode support arms 16 are formed, at the ends of the electrodes 6 are attached.

The illustrated state of the furnace A of FIG. 2 corresponds to the state of the furnace B of FIG. 6. Furnace B of FIG. 2 shows the state of the furnace completely open. By means of the pivoting device 12 or the supporting structure, both the furnace lid 5 - with the exhaust nozzle 26 attached thereto - and the O ₂ lance inner lid 21 are pivoted together with the lance 13 a.

In order to readjust the electrodes 6, which must be moved downwards a little because of the erosion of the electrode tips, the electrodes 6 with the pivoting column 11 are pivoted onto a central restoring device 20 (see FIG both stoves A and B is located.

The use of the third tilting platform 29 is possible with DC or AC double ovens. However, the design is particularly advantageous in a CONARC double-oven plant, in the different process steps, such as pig iron charging, dephosphorization, slag reduction u. Like. Be performed to apply.

LIST OF REFERENCE NUMBERS

A

Oven A

B

Oven B

1

foundations

2

substructure

3

tiltable oven platform or tilting frame

4

furnace vessel

5

furnace cover

6

electrodes

7

furnace transformer

8th

High current connection

9

Transformers house wall (Transformer house wall)

10

High current cables or high current cables

11

Pivoting column for electrode support arms and electrode inner lids

12

Swivel device for the lance, the furnace lid and the lance inner lid

13

Blow lances (a + b)

14

Support arms for the furnace lid and the lance inner lid

15

Lifting column for the electrode support arms

16

Electrode support device, electrode support arms

17

Support arms for the electrode inner cover

18

Electrode inner cover

19

Lifting cylinder for the electrode inner lid

20

Electrode slipping device

21

furnace cover

22

Lifting cylinder for the furnace lid

23

Exhaust pipe on the tipping frame

24

stationary exhaust pipe or exhaust pipe to Nachbrennkammer

25

afterburner chamber

26

flue outlet

27

Support arm for the lance

28

Support arm for the lance inner lid

29

third tilting platform or third tilting frame

30

own tilting drive or own drive to the third tilting frame

31

Piston-cylinder unit or tilt cylinder

32

Lifting column for the support arm of the lance

33

Lifting cylinder for the lance inner lid

Claims (9)

1. Twin-furnace plant for production of steel materials by alternate charging of batch materials containing iron, oxygen top blowing and arc smelting in each instance by means of a furnace A and a furnace B, which are each arranged on a respective tippable furnace platform (3), and with a raisable and lowerable electrode carrier device (16), which is arranged between the furnaces A and B, and a pivot device for at least one oxygen lance, wherein provided between the two tippable furnace platforms (3) is a third tipping platform (29) on which the pivotable, raisable and lowerable electrode carrier device (16) is arranged, and that the third tipping platform (29) is tippable in direct dependence on the tipping movements of a respective one of the furnace platforms (3) for a furnace vessel (4), wherein an own tipping drive (30) with a control device is associated with the third tipping platform (29) with the pivotable, raisable and lowerable electrode carrier device (16).
2. Twin-furnace plant according to claim 1, characterised in that the third tipping platform (29) together with the pivotable, raisable and lowerable electrode carrier device (16) is alternately lockable with the respective furnace platform (3) to be tipped.
3. Twin-furnace plant according to claim 1, characterised in that the control device of the own tipping drive (30) is formed from a synchronising device connectible with the control device of the respective furnace platform (3) to be tipped.
4. Twin-furnace plant according to one of claims 1 and 3, characterised in that the own tipping drive (30) is formed from a piston-cylinder unit (31) arranged within the foundation (1).
5. Twin-furnace plant according to one of claims 1, 3 and 4, characterised in that when the synchronising device is connected with the respective control device of a furnace platform (3) to be tipped a connection with the respective other control device for the respective other furnace platform (3) is blocked.
6. Twin-furnace plant according to one of claims 1 to 5, characterised by a cover pivot device for each furnace A and B, in which in each instance the pivot device for the oxygen lance (13a, 13b) is integrated, wherein the common pivot device (12) is arranged on the tippable furnace platform (3).
7. Twin-furnace plant according to claim 6, characterised in that the common pivot device (12) comprises a support structure for the furnace cover (5) and the oxygen lance cover (21) and a support arm (27), which is integrated therein, for the oxygen lance (13a, b) and that the electrode carrier device (16) has a support structure for the electrodes (6) and the electrode inner cover (18).
8. Twin-furnace plant according to claim 7, characterised in that the cover support structure and the electrode support structure have stroke cylinders (19, 22, 32), which are arranged to be distributed in correspondence with the geometric extent of the furnace cover (5), the oxygen lance cover (21) and the electrode inner cover (18) over the support arms (14, 17) forming the support structure and by way of which the respective covers are movable from an elevated pivot position to a lowered furnace closing position and from which the covers can be uncoupled.
9. Twin-furnace plant according to one of claims 1 to 8, characterised in that a waste gas duct through which waste gas is conducted away from the furnace during the smelting process or during the oxygen top blowing process is associated with each furnace (A, B) and that the waste gas duct is of multi-part construction, wherein a waste gas pipe (23) connected with the tipping platform (3) is connectible, in a pivoted-in position, with a afterburner chamber (25) by way of a stationary waste gas pipe (24) and that a waste gas stub pipe (26), which is arranged on the furnace cover (5), is constructed to be detachable relative to the waste gas pipe (23) and in the uncoupled state is pivotable together with the furnace cover (5).

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