JPH059543A - Refining lance - Google Patents

Abstract

PURPOSE: To provide an oxygen blowing lance which can mutually independently adjust the speed and the flow rate of gas stream and continuously shift the impact point to the bath surface during refining work.

CONSTITUTION: The refining gas stream is divided into at least two individually almost same jets around the center of flow-out refining gas stream in the downstream zone of a nozzle 12 freely adjustable in the body 2 of the lance 1, and a separating device 18 flowing out these jets from a lance head 3 into the directions having almost equal angle to the axial line of the lance and mutually facing in the diameter direction to the axial line, is arranged.

COPYRIGHT: (C)1993,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to refining lances. In particular, it relates to a refining lance for use in refining a molten metal by injecting an oxidizing refining gas into a molten metal bath contained in a metallurgical vessel.

[0002]

During the refining process of refining hot metal or iron alloys by jetting or blowing an oxidizing gas, generally technical oxygen, from above into a liquid metal bath in a metallurgical vessel. Depending on the progress of the refining process, it is of utmost importance whether the characteristics of the oxidizing gas flow and the injection point on the surface of the bath can be changed. This is even more important when modern refining technologies use primarily supersonic jets of oxidizing gas.

The manufacture of gas-blown lances designed for use in the refining process described above is complicated. In fact, the oxidizing gas is required on the one hand to react with the metal bath to produce a reaction such as the decarburization of iron, and on the other hand above the surface of the bath the post-combustion of carbon monoxide which results from the decarburization reaction. It is necessary to make sure that it occurs. Furthermore, it must be possible to adjust the amount of oxidizing gas blown into the vessel independently of the gas flow rate. Furthermore,
It is desirable to move the spot where the gas stream strikes the bath across the surface of the bath undergoing the refining operation to enlarge the area in which the metallurgical reaction takes place and to promote the stirring effect of the gas stream. Furthermore, the oxygen for post-combustion must be able to diffuse over the maximum reaction area of the bath surface, while at the same time the post-combustion of carbon monoxide is as close as possible to the bath surface, but the divergent energy does not lance. And / or not near the top of the vessel which could damage the vessel opening.

In Luxembourg 86322 (US Pat. No. 4,730,784-European patent 235,621), oxygen top blowing in which the outflow rate (Mach number) and the flow rate of the oxygen stream can be changed independently of one another Describes refining lances. This refined lance
Luxembourg Patent No. 87353 (US Patent Application No. 395,
No. 104), the operator changed the amount of primary oxygen supplied to the bath as a function of the progressive phase of the purification cycle and the optimum geometry required for the oxygen jet. Also, I try to give speed. According to Luxembourg No. 87353, the refining lance is provided with a nozzle for bundling and guiding the primary oxygen jet. The nozzle is formed by a conduit of variable cross section, which first defines a focusing segment, then a neck portion and finally a diverging segment. The nozzle has a central body movable along the axis of the nozzle at the level of the neck. This central body is
It has a shape in which a concavely tapered nose portion is continuous with a substantially cylindrical main portion. By moving this central body, the free cross-section of the neck and the shape of the widened part of the nozzle passage are modified, so that the operating parameters of the nozzle can be adjusted continuously.

[0005]

The oxygen-blown lance according to the invention is intended to improve the design of a novel metal refining lance by means of the apparatus described in Luxembourg Patent No. 87353 and by suitable incorporation methods. There is.

In Luxembourg No. 86321 (US Pat. No. 4,730,813), in connection with an oxygen top blowing refining lance, the oxygen flow exiting the lance head is, within certain limits, relative to the main axis of the lance. A device is described which is deflected and directed to impinge on various points on the surface of the bath to be purified. The apparatus according to Luxembourg Patent No. 86321 is provided in the vicinity of the outlet of the lance head with a chamber shaped almost like a truncated western pear. A gas jet impinging laterally on the main stream of primary oxygen exiting the nozzle near the exit level of the nozzle diverts this main stream to one side of a generally frustoconical chamber. This diverted flow travels along the wall of the chamber opposite the side from which the laterally deflected jet exits. By this method, the supersonic oxygen flow exits the opening of the lance head at a predetermined angle with respect to the axis of the lance body. This angle of deflection of the oxygen stream depends largely on the shape of the chamber wall. By providing several ports for the lateral gas jets and by directing the jets to the main stream in sequence, the impact point of this main stream on the surface of the metal bath shifts along the circumference, or Depending on the position of the lateral jets for deflecting, it is possible to direct a certain spot on the surface of the bath.

In this way, the supersonic main oxygen flow can be deflected, but the conventional lance gives a large lateral reaction force to the suspension and locking parts of the lance body, and the holding device. It is difficult to find a reliable solution to the problem associated with. Moreover, for the design of the lance according to this Luxembourg patent, the deflection of the main stream of primary oxygen occurs only in certain parts defined at specific positions corresponding to the ports of the laterally deflecting jets. There is a problem.

Therefore, it is an object of the present invention to blow oxygen in which the velocity and the flow rate of the gas stream can be adjusted independently of each other and the impact point on the surface of the liquid bath can be continuously moved during the refining operation. To get a lance.

[0009]

To achieve this object, the oxygen-blown refining lance of the present invention comprises a refining gas around the center of the effluent refining gas stream downstream of an adjustable nozzle within the body of the lance. Separation device for splitting a stream into at least two individual, substantially equal jets, which jets exit the head of the lance in diametrically opposite directions with respect to the axis of the lance at substantially equal angles. Is arranged.

[0010]

The preferred embodiments of the present invention will now be described with reference to the drawings.

As shown in FIGS. 1 and 2, the oxygen blowing lance 1 according to the present invention mainly comprises a lance head 3 welded to a lance body 2. This lance body 2
Consists of a double mantle of four walls 4, 5, 6 and 7 formed by concentric steel pipes, which are kept separated from each other by welding spacers,
Support the lance head 3. These elements of the lance body 2 form a water cooling circuit 9 bounded by three walls 4, 5, 6 and extending downwards towards the lance head 3.

The lance body and the method of suspending the fluid, for example the [transport] transfer, the nitrogen and cooling water supply pipes, are not shown in FIGS. 1 and 2 as they are not relevant for the purposes of the present invention.

The inner wall 7 of the lance body 2 has a Laval
l) Together with a concentric support shaft 11 supporting the lower end 12 of the nozzle form an annular space 10 when viewed in cross section in the direction of the longitudinal axis aa '. The support shaft 11 is preferably formed by a pipe that can be integrated with an electrical connection (not shown) for supplying electric current to various control mechanisms described below. According to another embodiment, the shaft 11 and the inner wall 7 itself can act as conductors for supplying current to the control mechanism described above.

The lower end 12 of the support shaft 11 in the form of a Laval nozzle is part of a translation piece 13 connected to the support shaft 11 via a drive mechanism such as a linear servomotor 14 and a cylindrical sleeve 15. And with which the abovementioned translation piece 13 can be moved in this sleeve in the direction of the axis aa ′ of the refining lance 1. As shown in FIG.
The lower end 12 of the translation piece 13 has a needle shape that draws a continuous aerodynamic streamline curve, so as to reduce turbulence generation of the purified gas flow.

Inside the wall 7 of the double mantle forming the lance body 2 is arranged a concentric conduit or duct 16 for the purified gas, ie primary oxygen. At the level of the translation piece 13, the concentric conduit 16 is provided with a constriction and a neck 17 to form a Laval nozzle with the needle-like head portion 12 of the translation piece 13, the characteristic or parameter of which is the translation piece 13. It can be changed by moving. This Laval nozzle allows the flow rate of the refining gas to be controlled independently of the supersonic velocity of the gas flow as it flows out of the Laval nozzle and as it concentrically flows into the neck 17 of the conduit 16.

The manner in which a Laval nozzle of varying cross section acts is described in detail in Luxembourg Patent No. 87353, the main features of which are described herein.

According to the invention, in the region downstream of the neck 17 of the purified gas conduit 16, the oxygen blowing lance 1 is
A separating device 18 (see FIG. 1) arranged around the center of the outflow channel of the supersonic gas stream is provided, which separates the gas stream aerodynamically exactly into at least two distinct and approximately equal supersonic speeds. Separate into jets. After exiting the separator 18, these supersonic jets of purified gas enter the head portion 3 of the lance and are deflected at a predetermined angle as described below.

The separating device 18 described above has the shape of a rotor and is arranged concentrically within the piece 40. This piece 40 is hermetically attached at its lower end to the lower part of the conduit 16. In the illustrated embodiment, the separating rotor device 18 is suspended on an upper support 21 and a lower support 22 as roll bearings. The upper part of the rotor 18 is constituted by an actuation mechanism or rotary drive mechanism 41 provided with drive blades 42 in the form of turbine blades. The central purified gas flow coming from the Laval nozzle impinges on the drive vanes 42, causing the rotor 18 to rotate. The rotation speed of the rotor device 18 is controlled and adjusted by a slit 43 (see FIGS. 3 and 4) provided immediately below the drive blade 42 in the rotor device 18. Breathing gas is blown through these slits 43. The braking gas is
It is preferable to use the same components as the purified gas. This gas, the so-called windbreak gas, is slit through the annular space formed by the wall 7 and the conduit 16 and then through the opening 44 in the piece 40.
Reaching 43.

The hollow interior of the rotor 18 is, in the illustrated embodiment, divided into two separate chambers by a central ramp 45 to provide an aerodynamically accurate center supersonic flow of the oxidized purified gas coming from the Laval nozzle. Individual but identical (nearly identical)
Divide into supersonic jets.

FIG. 1 shows two partial cross-sections of a rotor selected to show a channel 46 for one of the two supersonic purified gas jets on the left side and a split center ramp 45 on the right side. . As shown in FIG. 1, the gas duct 47 is
It occupies a part of the downstream region of the split lamp 45. This gas conduit 47
Communicates with the outflow nozzle 48 of the head 3 of the lance 1 through the perforated rotor front wall 49. As described in detail below, the supersonic flow of the oxidizing gas flowing into the gas conduit 47 flows from the perforated rotor front wall 49 into the outflow nozzle 48, and this outflow nozzle 48,
It occupies the space created between two purified gas supersonic jets. The side wall 50 of the outflow nozzle 48 has a so-called “Coanda effect”.
Under "Coanda-effect", the supersonic refined gas jet coming from the channel 46 of the rotor 18 has a curvature that deflects laterally by a predetermined angle with respect to the central axis aa 'of the lance 1. The lateral deflection of this split purified gas jet is
It is promoted by the pressurized gas flow exiting the gas duct 47 at supersonic speed. The pressurized gas flow exiting the gas duct 47 at supersonic speed surrounds and guides the supersonic jet and maintains it in one direction away from the central axis aa 'of the lance 1. Although the formation and deflection of one purified gas supersonic jet has been described above, the other purified gas supersonic jet also flows out of the rotor 18 and at a predetermined same angle with respect to the central axis aa 'of the lance 1, It will be apparent to those skilled in the art to deflect laterally at an angle towards the diametrically opposite direction of the direction of the first jet. Due to the uniqueness of this jet,
The lance is not subject to radial dynamic forces (although there are residual moments acting on the rotor). In the device according to the invention, the supersonic jet forces are neutralized because the forces cancel each other out. Therefore, the attachment for supporting and guiding the refining lance 1 according to the invention is also free from the stresses that result from the deflection of the supersonic jet of the refining gas with respect to the lance axis (Luxembourg Patent No. 86321). It is described that the conventional device is subjected to such stress).

According to another feature of the invention, the head of the rotor 18 imparts rotational movement to the jet. As a result, the point at which the jet of refining gas hits the surface of the liquid metal bath in the refining process moves continuously along a circular path. The radius of this path is a function of the jet deflection angle and the distance between the head of the lance 3 and the bath. The deflection angle of the supersonic jet of purified gas depends on the side wall 50 of the outlet nozzle 48.
Is a function of the curvature of.

In the preferred embodiment of the apparatus of the present invention shown in FIG. 1, the idea of the head of the lance 3 is that the head can be easily and quickly attached to the lance body and removed from the lance body. Has been selected. Although the drawings do not show all the details in order to avoid congestion, it is not necessary for a person skilled in the art to completely attach all the pieces forming the head of the lance 3 to the rotor 18, and to attach the rotor 18 completely. It is well known.

For these reasons, such a lance allows rapid replacement of all pieces which are subject to the effects of high temperatures during the operation of the lance or to the wear of the so-called splashing of liquid metal particles from the bath. Furthermore, the rotor 18 and the side wall 50 of the head 3 of the lance 1 can be replaced quickly.

As is apparent from FIG. 1, the rotor 18 is located slightly rearward of the outlet orifice 33 of the lance head 3 to protect the lance head 3 from liquid metal particles which are scattered during the refining operation.

Post-combustion nozzle 34
On the lance head 3 around the central orifice 33. In the illustrated embodiment, eight nozzles are provided.
These nozzles are arranged at equal intervals along the circumference of the lance head. Preferably, the post-combustion nozzle 34 is a "double prandle nozzle" as described in Luxembourg Patent No. 87354.
(double Prandle-Meyer) effect ”form. Such a nozzle constitutes an almost continuous gas screen, like an umbrella, around two supersonic jets of purified gas. The post-combustion nozzle 34 is supplied with oxygen by means of a secondary gas flow and for this purpose is provided with an annular space between the walls 6 and 7 of the double mantle of the lance 1. This supersonic secondary gas flow is also generated by the openings 51 and the annular chamber 52 arranged in the wall of the concentric piece 40.
The supersonic gas flow passing through the gas duct 47 by the rotor 18
The vertical front wall 49 is maintained in the vertical direction. The dimensions of the apertures 51 are approximately equal to the amount of gas that is diverted to the perforated rotor front wall 49 via the gas duct 47 and the secondary gas post-combustion nozzle 34.
To be able to supply.

[0026]

INDUSTRIAL APPLICABILITY The present invention relates to a processing facility of an iron mill,
Provide a special injection lance for a metallurgical vessel for refining a molten metal bath with oxidizing gas. In fact, according to the idea of the invention, this special lance allows the lance to change the characteristics of the refined gas stream by means of a variable Laval nozzle, even during the refining process, and further divides the gas stream and separates the individual jets generated. A mechanism of rotation and diversion allows the impingement point of each individual jet to be sprayed onto the surface of the bath.

The penetration of each supersonic refining gas jet into the molten metal bath is ensured during the whole process of the refining operation, and this bath can also stir the slag suspended in the bath.

The lance is designed so that it is not subjected to mechanical stress during operation which would impair operating efficiency and reliability. The secondary gas stream protects the rotating parts of the lance from the destructive effects of flying molten metal particles, and these jets of secondary gas are necessary for the post-combustion of the reaction gases leaving the bath during the refining process. Supply oxidizing gas.

The above description merely describes the preferred embodiments of the present invention, and it is needless to say that various modifications can be made within the scope of the claims. For example, it is within the scope of the invention to use not only the main supersonic gas stream of purified gas to divide into two equal jets but also other numbers of equal jets. Is.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a downstream region portion having a rotor head of a lance body of an embodiment of a lance according to the present invention, in which a right half and a left half are cross-sectional views which are deviated from each other by 90 °.

FIG. 2 is a vertical cross section of an upstream region of the lance body shown in FIG.

3 is a vertical cross-sectional view of the rotor body of the lance shown in FIG.

FIG. 4 is a cross section taken along the line AA in FIG.

[Explanation of symbols]

1 Oxygen blowing lance 2 Lance body 3 lance head 4, 5, 6, 7 wall 9 Water cooling circuit 10 annular space 11 Support shaft 12 Lower end (Laval nozzle) 13 Translation piece 14 Linear servo motor 15 sleeve 16 ducts 17 Neck 18 Separation rotor device 21, 22 Roll bearing 33 Outflow orifice 34 Post-combustion nozzle 40 pieces 41 Rotation drive mechanism 42 drive wing 43 slits 44 holes 45 split center lamp 46 channels 47 gas duct 48 outflow nozzle 49 Perforated rotor front wall 50 side wall 51 holes 52 Ring room

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[Procedure amendment]

[Submission date] December 10, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 10

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

Post-combustion nozzle 34
On the lance head 3 around the central orifice 33. In the illustrated embodiment, eight nozzles are provided.
These nozzles are arranged at equal intervals along the circumference of the lance head. Preferably, the post-combustion nozzle 34 is a "double prandle nozzle" as described in Luxembourg Patent No. 87354.
(double Prandle-Meyer) effect ”form. Such a nozzle constitutes an almost continuous gas screen, like an umbrella, around two supersonic jets of purified gas. The post-combustion nozzle 34 is supplied with oxygen by means of a secondary gas flow and for this purpose is provided with an annular space between the walls 6 and 7 of the double mantle of the lance 1. This secondary gas flow of the subsonic also causes the subsonic gas flow passing through the gas duct 47 by the opening 51 and the annular chamber 52 arranged in the wall of the concentric piece 40 to be perpendicular to the direction of the perforated front wall 49 of the rotor 18. Maintain orientation.
The size of the opening 51 is such that the front wall 49 of the perforated rotor passes through the gas duct 47.
The secondary gas is selected to be capable of being supplied to the post-combustion nozzle 34 in an amount approximately equal to the amount of gas diverted to

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Patrick Delugs             Country of Luxembourg El-8356 Garnits             Shuriyu Deshiyan 17 (72) Inventor Carlo Heinz             Country of Luxembourg El-2154 Squaw             Le Alloy Mayer 2 (72) Inventor Carlo Lux             Country of Luxembourg El-8054 Beltra             Ndjyuriyu de Darius 5 (72) Inventor Robert Moselle             L-Luxembourg El-3422 Dude             Runge Yuryu Komto Berthier 20 (72) Inventor François Uttrie             Country of Luxembourg El-3563 Dude             RANJYURYU M MUYU Mitsu 9

Claims (11)

[Claims] 1. A cross section is adjusted to independently adjust the speed and flow rate of a purified gas flow, because the purified gas is used for injecting an oxidized purified gas into a molten metal bath contained in a metallurgical vessel to refine the molten metal. In a refining lance with a free coaxial nozzle assembly (12-16), the lance (1)
Around the center of the effluent purified gas stream downstream of the adjustable nozzle (12) in the body of the jet, the purified gas stream is divided into at least two individual, approximately equal jets, which lances (1) A separating device (18) which makes an approximately equal angle with respect to the axis (a-a ') of the lance, and which flows out from the head (3) of the lance in a direction diametrically opposed to the axis (a-a'). Purification lance characterized by having been placed. 2. The refining lance according to claim 1, further comprising drive means (41) for rotating the separating device (18) around an axis (aa ') of the lance (1). 3. The adjustable nozzle (12) is in the form of a Laval nozzle which imparts a supersonic velocity to the purified gas stream, the Laval nozzle varying the characteristics of the nozzle passage and independently of the velocity. The refining lance according to claim 1 or 2, further comprising adjusting means (14) arranged at a position for controlling the flow rate of the refining gas. 4. The method according to claim 1, wherein the separating rotor device (18) has a cylindrical shape, and the hollow portion inside the cylindrical shape is separated into at least two equal chambers by a split center lamp (45). The purification lance according to any one of items. 5. A gas duct (47) is integrated in a downstream region below the central split lamp (45), the gas duct (47) is opened to the head (3) of the lance (1), and the supersonic velocity of gas is increased. The refining lance according to claim 4, wherein the refining lance is fed by a flow to fill a gap between the refined gas supersonic jets. 6. An inner side wall (50) of the head (3) of the lance defines an outflow nozzle (48) in which the so-called "purified gas jet outflowing from the central split lamp (45)". Due to the "Coanda effect", the axis of the lance (1) (a-
a ') forms an almost equal angle with respect to the axis (a-
The refining lance according to any one of claims 1 to 5, wherein the refining lance has a curvature that is diametrically opposed to a '). 7. The separation rotor device (18) is provided with a lance (1).
7. The refining lance according to any one of claims 1 to 6, wherein the refining lance is attached to the main body in a detachable and replaceable manner. 8. A drive mechanism for imparting rotary motion to a separating device (18).
The refining lance according to any one of claims 2 to 7, wherein the (41) has a driving blade (42) in the shape of a turbine blade. 9. The rotation speed of the separating device (18) is controlled and adjusted by slits (43), and these slits (43) are driven blades (42).
Installed in the separating device (18) directly under the
The refining lance according to claim 8, wherein the braking gas is injected to the (43). 10. A lance head (3) is provided with a post-combustion nozzle (34), and a secondary supersonic flow of an oxidizing gas is supplied to this post-combustion nozzle (34). The purification lance according to any one of items. 11. A refining lance according to claim 1, wherein a water supply cooling circuit (9) is provided integrally with the double mantle part of the lance (1) and the head part (3). .