EP0490100A1 - Blaslanze - Google Patents

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Publication number
EP0490100A1
EP0490100A1 EP91119297A EP91119297A EP0490100A1 EP 0490100 A1 EP0490100 A1 EP 0490100A1 EP 91119297 A EP91119297 A EP 91119297A EP 91119297 A EP91119297 A EP 91119297A EP 0490100 A1 EP0490100 A1 EP 0490100A1
Authority
EP
European Patent Office
Prior art keywords
lance
gas
refining
blowing
head
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP91119297A
Other languages
English (en)
French (fr)
Inventor
Victor Bleser
André Bock
Patrick Derungs
Carlo Heintz
Carlo Lux
Robert Mousel
François Witry
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Arcelor Luxembourg SA
Original Assignee
Arbed SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Arbed SA filed Critical Arbed SA
Publication of EP0490100A1 publication Critical patent/EP0490100A1/de
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/42—Constructional features of converters
    • C21C5/46—Details or accessories
    • C21C5/4606—Lances or injectors

Definitions

  • the present invention relates to a blowing lance, in particular a blowing lance for a gas used for refining metals in their liquid state.
  • the design of the blowing lance used in the context of a refining process as described above is complex. Indeed, the oxidizing gas must on the one hand be able to react reciprocally with the metal bath so that the reactions, such as decarburization can take place, and on the other hand be able to ensure above the surface of the bath a post-combustion of the carbon monoxide released. It must also be ensured that the quantities of oxidizing gas injected can be regulated independently of the speed of the gas jet. A displacement of the point of impact of the gas jet on the surface of the bath during the refining process is in more desirable in order to increase the surface where the metallic reactions take place and to intensify its stirring effect in the bath.
  • the post-combustion oxygen must, moreover, be able to embrace the widest possible reaction zone, while ensuring that the post-combustion of carbon monoxide takes place near the surface of the bath and not in the regions where the energy released would jeopardize the lance itself.
  • the Luxembourg patent No. 86 322 (US 4,730,784, EU 0 235 621) describes an oxygen blowing lance nozzle for refining metals which makes it possible to vary the exit speed (the Mach number) and the flow rate of the jet of oxygen independently of each other.
  • a further development of such a blowing lance which allows the operator to vary, according to the different refining phases, the quantity of oxygen introduced into the bath while imposing on the jet of oxygen the shape and the speed optimal required, is the subject of Luxembourg patent No. 87 353 (US SN 395,104). According to the device of the Luxembourg patent No.
  • the blowing lance has a nozzle for forming and guiding the jet of refining oxygen, comprising a duct with variable section sketching a convergent followed by a neck and a diverging , the nozzle being provided with a central part movable along the axis of the nozzle at the neck.
  • the central part has a shape having a substantially cylindrical body and a nose tapering concavely to a point.
  • blowing lance of the present invention makes use of the device described in Luxembourg patent No. 87 353 which will advantageously be incorporated in the design of this new blowing lance for refining metals.
  • the supersonic jet of refining oxygen comes out of the mouth of the lance head at a angle relative to the axis of the lance, the deflection angle depending to a large extent on the shape of the wall of said chamber.
  • the supersonic refining oxygen jet can be deflected in this way, the lance is subjected to strong lateral reaction forces which stress the suspension and anchoring points of the lance so much that 'it is difficult to find a reliable solution to these fixing problems in practice. Furthermore, the device according to the Luxembourg patent only allows the deflection of the refining oxygen jet at certain points or well-defined locations.
  • the object of the present invention is to design a blowing lance capable of providing a jet of gas whose speed and flow can be adjusted independently of one another, and whose point of impact on the surface of the bath liquid can be moved continuously during the refining operation.
  • the blowing lance (1) comprises a lance body (2) welded to a lance head (3).
  • the lance body (2) comprises a mantle with four walls (4, 5, 6 and 7) concentric in welded steel tubes, spaced apart by intermediate pieces and connected to the lance head (3), to form a circuit. water cooling (9) between the walls (4, 5 and 6) and those of the lance head (3).
  • the inner wall (7) of the lance body (2) forms an annular chamber (10) crossed along its axis a-a 'by a concentric rod (11) for supporting an assembly forming a Laval nozzle (12).
  • the support rod (11) is preferably formed by a tube which allows the installation of electrical connections (not shown in the Figures) for supplying electric current to the various control mechanisms which will be described later.
  • the rod (11) and the inner wall (7) can themselves act as conductors for the supply of electric current to said control mechanisms.
  • the assembly forming the Laval nozzle (12) comprises a translation body (13) attached to the support rod (11) by means of a control mechanism composed of a linear servomotor (14) and a cylindrical sheath (15) in which the translation body (13) can move in the direction of the axis aa 'of the blowing lance (1).
  • the end of the translation body (13) has the shape of a kind of needle whose profile follows a continuous aerodynamic transition curve, in order to minimize the creation of turbulence in the refining gas flow.
  • a concentric conduit (16) for the refining gas that is to say the primary oxygen, is arranged.
  • the concentric conduit (16) has a converging part and a neck, which, in cooperation with the needle of the translation body (13), form a Laval nozzle, the characteristics or parameters can be modified by moving the translation body (13) in the direction of the axis a-a '.
  • This Laval nozzle makes it possible to control the flow rate of the refining gas independently of the supersonic speed that the jet of refining gas will take when leaving the Laval nozzle by discharging centrally in the part (17) of the conduit (16 ).
  • variable Laval nozzle (12) The operation of the variable Laval nozzle (12) is described in more detail in Luxembourg patent No. 87 353, the description of which is incorporated into that of the present patent application.
  • the blowing lance (1) Downstream of the part (17) of the conduit (16) of the refining gas, the blowing lance (1) comprises, according to the present invention, a device (18) (see Figure 1a), arranged centrally in the flow of the supersonic jet of the refining gas, in order to separate the latter aerodynamically correct into two distinct and almost equal supersonic jets.
  • a device (18) see Figure 1a
  • These two supersonic refining gas jets open, at the outlet of the separating device (18), into the lance head (3) in which they undergo a deflection at a determined angle, as will be explained later.
  • the separating device (18) is executed in the form of a rotor which is housed in a stationary concentric piece (40) fixed in a sealed manner to the lower part of the duct (16) and in extension thereof.
  • the rotor (18) is suspended from the upper support (21) and the lower support (22) which both have a ball bearing.
  • the rotor (18) is provided in its upper part with a drive or rotation mechanism (41) which comprises drive vanes (42) in the form of turbine blades.
  • the central jet of gas leaving the Laval nozzle (13) collides with the fins (42) and sets the rotor (18) in rotational movement.
  • the rotational speed of the rotor (18) is controlled and adjusted by means of slots (43) (see Figures 2 and 3) arranged in the rotor (18) downstream of the drive fins (42), through which a braking gas, preferably of the same composition as the refining gas, is blown.
  • This braking gas called tertiary gas, is brought to the slots (43) through the annular space formed between the wall (7) and the conduit (16), and the openings (44) in the part (40).
  • the hollow interior of the rotor (18) is divided into two chambers separated by a central ramp (45) to cause aerodynamically correct separation of the jet central supersonic coming out of the Laval nozzle (13) in two distinct but identical (or almost identical) supersonic jets.
  • FIG. 1a the sectional view of the rotor has been made so that the left part shows the channel (46) of one of said supersonic refining jets and the right part the separation ramp (45).
  • a duct (47) is arranged in the lower part (downstream) of the separation ramp (45), this duct opening into the nozzle (48) of the lance head (3) by a perforated wall (49).
  • the duct (47) is supplied, as will be described below, by a subsonic flow of oxygen, to fill the space between the two supersonic jets of refining gas in the blowing nozzle (48) of the head lance (3).
  • the walls (50) of the blowing nozzle (48) have a curvature such that under the so-called "Coanda” effect the supersonic jet of refining gas leaving the channel (46) of the rotor (18) is deviated from an angle determined with respect to the central axis aa 'of the lance (1).
  • This deflection of the refining gas jet is supported by the pressurized flow of subsonic gas leaving the conduit (47) which envelops and guides the supersonic jet maintaining it in the direction deflected with respect to the central axis aa of the lance. (1).
  • the other refining jet leaves the rotor (18) and the nozzle of blowing (48) identically (or almost identical) at the same angle (or almost same angle) but in a direction diametrically opposite to the first refining jet with respect to the central axis (a-a ') of the lance (1).
  • the blowing lance (1) is not subjected to radial dynamic forces (apart from the existence of a residual torque acting on the rotor), since these forces, due to supersonic jets, are compensate for each other in the device according to the present invention.
  • the supports for fixing and guiding the refining lance (1) of the present invention are therefore not subjected to stresses due to the deflection of the supersonic refining jet relative to the axis of the lance, as such was the case for the devices of the state of the art as described in the Luxembourg patent No. 86 321.
  • the rotor (18) drives the two supersonic jets of refining gas in a rotational movement, so that their points of impact on the surface of the liquid metal bath are, during the refining process, moved continuously in a circle, the radius of which is determined by the angle of deflection of the jets and the distance between the lance head and the metal bath.
  • the deflection angle of the supersonic refining gas jets is a function of the shape of the deflection wall (50) of the blowing nozzle (48).
  • the design of the lance head (3) was chosen in the example of a preferred embodiment of the device according to the invention shown in Figure 1a, so as to allow its easy and quick assembly and disassembly to the body or rod. spear. Although in the drawing we do not show all the details of execution, it becomes apparent to those skilled in the art that all the parts which form the lance head (3) and the rotor are nested one in the the other.
  • This design therefore allows rapid exchange of all parts subject to wear, either under the influence of high temperatures prevailing at this location, or by the projection of splashes of molten metal. It also allows rapid exchange of the rotor (18) as well as of the wall (50) of the lance head (3).
  • the rotor (18) is installed slightly behind the outlet orifice (33) of the lance head (3), this to protect it against the projection of particles of liquid metal during the refining process.
  • Post-combustion nozzles (34) are arranged in the lance head (3) around the central orifice (33).
  • the nozzles (34) are eight in number in the embodiment shown, arranged uniformly on around the lance head.
  • these post-combustion nozzles (34) are of the "double Prandtl-Meyer" type, as described in Luxembourg patent No. 87 354. They form a practically uninterrupted screen, in the form of an umbrella. , around the two supersonic jets of refining gas.
  • the post-combustion nozzles (34) are supplied with oxygen by a secondary flow of gas circulating in the annular space between the walls (6) and (7) of the mantle of the lance (1).
  • the dimensioning of the openings (51) has been chosen, in the example shown, so as to route, in substantially equal proportions, the flow of secondary gas to the post-combustion nozzles (34) and to the conduit (47) of the ramp (45).
  • the present invention makes available for a method of refining a molten metal bath, a blowing lance which, by its clever design, makes it possible to modify, even during refining, the characteristics of the jet of gas d refining by means of an adjustable Laval nozzle (13) and of displacing its point of impact on the liquid bath during refining by means of a mechanism for dividing rotation and direction (18, 27).
  • the design of the lance is such that it is not subjected in service to mechanical stresses which would question its effective operational use.
  • a secondary gas flow protects the rotating parts against destructive effects from the metal bath, and secondary gas jets provide for post-combustion of the gases escaping from the molten metal bath during the refining process.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
EP91119297A 1990-12-10 1991-11-13 Blaslanze Withdrawn EP0490100A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
LU87856 1990-12-10
LU87856A LU87856A1 (fr) 1990-12-10 1990-12-10 Lance de soufflage

Publications (1)

Publication Number Publication Date
EP0490100A1 true EP0490100A1 (de) 1992-06-17

Family

ID=19731266

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91119297A Withdrawn EP0490100A1 (de) 1990-12-10 1991-11-13 Blaslanze

Country Status (3)

Country Link
EP (1) EP0490100A1 (de)
JP (1) JPH059543A (de)
LU (1) LU87856A1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4221266C1 (de) * 1992-06-26 1993-10-21 Mannesmann Ag Verfahren und Vorrichtung zum Aufblasen von Sauerstoff auf Metallschmelzen

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
LU39781A1 (de) * 1960-03-23 1961-04-15
LU57675A1 (de) * 1968-01-25 1969-04-15
LU56138A1 (de) * 1968-05-24 1970-01-14
EP0055956A1 (de) * 1980-12-22 1982-07-14 INSTITUT DE RECHERCHES DE LA SIDERURGIE FRANCAISE (IRSID) France Lanze zum Einblasen eines oxydierenden Gases, speziell von Sauerstoff, zur Behandlung von Metallschmelzen

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
LU39781A1 (de) * 1960-03-23 1961-04-15
LU57675A1 (de) * 1968-01-25 1969-04-15
LU56138A1 (de) * 1968-05-24 1970-01-14
EP0055956A1 (de) * 1980-12-22 1982-07-14 INSTITUT DE RECHERCHES DE LA SIDERURGIE FRANCAISE (IRSID) France Lanze zum Einblasen eines oxydierenden Gases, speziell von Sauerstoff, zur Behandlung von Metallschmelzen

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 11, no. 202 (C-432)(2649) 30 Juin 1987 & JP-A-62 023 921 ( KAWASAKI ) 31 Janvier 1987 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4221266C1 (de) * 1992-06-26 1993-10-21 Mannesmann Ag Verfahren und Vorrichtung zum Aufblasen von Sauerstoff auf Metallschmelzen

Also Published As

Publication number Publication date
JPH059543A (ja) 1993-01-19
LU87856A1 (fr) 1992-08-25

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