JP2001032011A - Top-blown lance for blowing into molten metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a top-blown lance for blowing into molten metal which can smoothly supply cooling medium into a furnace separately from oxidizing gas and cooling water in a comparatively simple structure without needing larger size than the conventional triple tubes. SOLUTION: The top-blown lance 4 for blowing into the molten metal is composed of an inner tube 12 for supplying the oxidizing gas, an middle tube 13 for forming a supplying path 2 of cooling water for cooling the inner tube 12, an outer tube 10 for forming a drainage path 3 of the cooling water and a nozzle 5 fitted to the lower end of the inner tube 12 and blowing the oxidizing gas into the molten metal held in a converter type reaction vessel. In such a case, plural tube bodies 14 for forming the flowing path of hydrocarbon base cooling medium 8 are disposed in mutually parting state between the outer tube 10 and the middle tube 13 and opened toward the outside of the outer tube 10 in each tube body, and a sub-nozzle 11 for spouting the cooling medium to the outside of the lance, is fitted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an upper blowing lance for blowing molten metal, and more particularly to an upper blowing lance which is effective when a solid material containing oxides is melted and reduced by a carbon material in a converter type reaction vessel. About.

[0002]

2. Description of the Related Art An oxidizing gas (for example,
A typical example of a molten metal smelting or refining vessel equipped with a lance for blowing up oxygen or a mixed gas of oxygen and an inert gas) is a converter type reaction vessel. For example, in a converter type reaction vessel (hereinafter simply referred to as a converter), an oxidizing gas is blown from a lance into a molten material (metal, slag, etc.) held in the furnace, and an oxidation refining reaction such as a decarburization reaction is performed. In general, a solid material containing a carbon-based solid fuel and an oxide of a metal to be blown is charged into the melt, and then the oxidizing gas is passed through the top blowing lance. At the same time as burning the carbon-based solid fuel to dissolve the oxide of the refining target metal charged into the furnace and reducing the oxide with carbon or a reducing gas in the furnace by the so-called "melting reduction method". Blowing may take place.
In any case, the upper blowing lance used and the gas blowout holes (hereinafter, referred to as nozzles) attached to the upper lances are used to blow molten steel or combustion during oxidizing gas blowing (hereinafter, blowing). Since the lance is heated intensely by radiant heat from the object, the upper blowing lance has a water cooling structure as shown in FIG. That is, the pipe is a triple pipe, and the flow path 1 of the oxidizing gas is sequentially formed from the center, and the surroundings thereof are the cooling water supply path 2 and the drain path 3. The nozzle 5 attached to the upper blowing lance 4 is usually attached to the lower end of the upper blowing lance 4 in order to blow an oxidizing gas for blowing onto the steel bath surface. However, recently, Japanese Patent Laid-Open No. 10-251731
As disclosed in Japanese Patent Laid-Open Publication No. H11-107, a nozzle (hereinafter, referred to as a sub-nozzle) different from the one for blowing the oxidizing gas is used to dissolve metal and the like adhered to the inner wall of the furnace opening of the converter. 4
There is also an upper blowing lance which is mounted not on the lower end but on the outer peripheral surface in the middle with its tip directed obliquely downward or horizontally to supply oxidizing gas to the space above the steel bath surface.

[0003]

Incidentally, in order to increase the amount of heat supplied to the molten metal during the above-mentioned smelting reduction smelting, a part of the oxidizing gas supplied from the lance is generated in the furnace. In general, so-called secondary combustion for burning CO gas is performed. In addition, even in a normal oxidation refining reaction other than smelting reduction, secondary combustion may be performed for the purpose of increasing the amount of heat supplied to the molten metal even when the temperature of the hot metal of the raw material is insufficient.

In any case, such a secondary combustion reaction inevitably raises the temperature of the upper space in the furnace, which significantly increases the heat load applied to the refractory lining the upper part of the converter. There is a problem that its life is shortened. In order to reduce the heat load of the refractory lining on the upper part of the converter, as shown in FIG. 6, cooling is performed from the longitudinal direction of the upper blowing lance 4 toward the furnace wall refractory 6 and the furnace mouthpiece 7. A technique for injecting another type of refrigerant (hydrocarbon-based fluid, for example, heavy oil, etc.) 8 having high performance has been developed (for example, Japanese Patent Application Laid-Open No. 61-67).
708). In Japanese Patent Application Laid-Open No. 61-67708, the flow path of the refrigerant is provided at the outermost periphery of the lance, but this is not practical. Since the amount of refrigerant injected, such as hydrocarbons, is much smaller than the flow rate of the cooling water in the lance, arranging such a small amount of fluid flow path at the outermost periphery of the lance results in insufficient cooling of the outermost tube of the lance. This is because the lance may be melted. Therefore, in the case of a lance having a multiple pipe structure having a cooling water flow path, as shown in FIG. 4, the flow path of a refrigerant such as a hydrocarbon is provided at the innermost of the multiple pipe so as not to affect the cooling of the lance. It must be formed around the circumference. However, when the refrigerant 8 is injected from such an innermost tube through the sub-nozzle 11, the structure of the upper blowing lance 4 becomes much more complicated than that of the conventional one. The refrigerant 8
In order to keep the pressure loss low, the outer diameter of the upper blowing lance 4 must be increased as compared with the conventional case, and there is another problem that the space for arranging the apparatus and the cost are increased.

In view of such circumstances, the present invention has a relatively simple structure without increasing the size of a conventional triple tube.
An object of the present invention is to provide an upper blowing lance for blowing molten metal capable of smoothly supplying another type of refrigerant into a furnace separately from an oxidizing gas and cooling water.

[0006]

Means for Solving the Problems In order to achieve the above object, the inventor of the present invention has intensively studied the best method for smoothly supplying a refrigerant other than an oxidizing gas and cooling water into a furnace. As a result, the inventors have conceived of independently providing the flow path of the refrigerant in the cooling water path, and have completed the present invention.

That is, the present invention provides an inner pipe for supplying an oxidizing gas, an inner pipe surrounding the inner pipe to form a supply path of cooling water for cooling the inner pipe, and a drain pipe for the cooling water. An outer tube to be blown and a nozzle attached to the lower end of the inner tube, and a nozzle for blowing an oxidizing gas into the molten metal held in the converter type reaction vessel. And a plurality of pipes that form a flow path for the hydrocarbon-based refrigerant are spaced apart from each other, and each of the pipes is opened in a manner similar to the outer pipe, and the refrigerant is lanced. An upper blowing lance for blowing molten metal, wherein a sub-nozzle for spraying outside is mounted.

The present invention also provides an upper blowing lance for blowing molten metal, wherein the sub-nozzles are mounted in a plurality of stages in a longitudinal direction of the lance.

Further, the present invention is an upper blowing lance for blowing molten metal, wherein the sub-nozzle is fixed to an outer tube and slidably contacts the middle tube.

[0010] In addition, the present invention is also an upper blowing lance for blowing molten metal, wherein the tube is curved in a longitudinal direction.

According to the present invention, a plurality of independent tubes are provided in a cooling water drain formed by the outer tube and the middle tube, and the inside of the tubes is different from the oxidizing gas and the cooling water. Since the refrigerant is allowed to pass through and injected into the furnace through the sub-nozzle, the refrigerant can be smoothly blown into the furnace without increasing the size of the upper blowing lance as compared with the conventional case.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a typical example of the top blowing lance according to the present invention.
(A), (b) and FIG. Its basic part is the same as a conventionally known triple tube lance. In other words, the triple pipes are, from the inside, the inner pipe 12, the middle pipe 13, and the outer pipe 1 respectively.
0, the inside of the inner pipe 12 is an oxidizing gas flow path 1, the space between the inner pipe 12 and the middle pipe 13 is a cooling water supply path 2,
A drain passage 3 is provided between the outer pipe 10 and the outer pipe 10. In the present invention,
In the upper blowing lance 4 having such a structure, a plurality of pipes 14 that form the hydrocarbon-based refrigerant flow path 9 are separately arranged between the outer pipe 10 and the middle pipe 13 so as to be separated from each other. At the same time, the sub-nozzles 11 for injecting the refrigerant 8 were attached to the respective pipes 14. FIG. 1 shows an example in which the number of the pipes 14 is four.
Depending on the purpose of use of the refrigerant 8, a maximum of about eight is preferable. The reason for this is that the outer diameter of each pipe may be small, so that it is possible to pass the necessary amount of refrigerant 8 for in-furnace injection without making the cooling water drainage passage 3 narrower than before. It is. That is, since the cooling capacity of the outermost tube is not reduced, it is not necessary to arrange the refrigerant flow path on the inner periphery of the lance as shown in FIG. 4, so that the arrangement of the sub-nozzles becomes easy. The tip of the sub-nozzle 11 may be oriented in the horizontal direction or may be inclined ± 45 ° from the horizontal. Further, the structure of the sub-nozzle 11 is preferably such that the sprayed refrigerant 8 spreads radially. This is because it is desired to cool the atmosphere in the furnace widely.

Next, in the present invention, the sub-nozzle 11
May be attached not only at one position in the longitudinal direction but also at a plurality of stages. This is because it is more convenient to inject the refrigerant 8 to a required position (furnace fitting 7, furnace wall refractory 6, etc.) in the converter type reaction vessel 17.

By the way, when the use place of the upper blowing lance 4 is relatively low and the temperature difference between the outer tube 10 and the middle tube 13 is small, the tube 14
What is necessary is just to fix and arrange | position suitably. However, where the ambient temperature in the vessel is as high as 1800 ° C., such as when the molten metal (hot metal or the like) 15 is subjected to smelting reduction blowing, a large temperature difference usually occurs, and the outer pipe 10 and the middle pipe 15 13 due to the difference in thermal expansion of the tube 13 (cracking of the tube 14,
(Damage) etc. may occur.

Therefore, in the present invention, as shown in FIG. 3, the sub-nozzle 11 is connected to the sub-nozzle block 20 in order to reduce the difference in extension between the outer tube 10 and the middle tube 13 when receiving a thermal load.
Even if it is locked and fixed to the outer tube 10 via the inner tube 13, the inner tube 13 has a rubbing structure that only makes contact with the rubbing surface so that they can slide with each other. Further, since the elongation of the tube 14 itself varies depending on the temperature, as shown in FIG.
3 so as to reduce the difference in thermal elongation with the outer tube 10. Further, the pipe 14 does not have a straight pipe from the upper end of the upper blowing lance 4 to the position of the sub-nozzle 11, but is curved in the longitudinal direction as shown in a developed view of the lance in FIG.
As a result, a certain amount of elongation can be secured, and the outer tube 10
This is because the difference in thermal elongation with the above can be reduced.

In addition, in the present invention, since a plurality of tubes 14 are provided, a header (not shown) is provided above the upper blowing lance 4 in order to make the supply amount of the refrigerant 8 uniform in each tube 14. It is preferable to arrange them. This is because it is desired to uniformly cool the furnace atmosphere, the furnace fitting 7 and the furnace wall refractory 6.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A converter type reaction vessel 17 equipped with a top blowing lance 17
(Heat size: 150 tons) was used to blow molten steel for smelting stainless steel. 150 tons of hot metal 15 (temperature: 1300 ° C.), which had been desiliconized, dephosphorized, and desulfurized in a preliminary treatment, was charged into the vessel 17. Thereafter, a predetermined amount of iron scrap, Cr ore, and a solid reducing agent were charged into the hot metal 15, and oxygen gas 18 was blown through the upper blowing lance 4 to melt and reduce the Cr ore and the like to obtain molten steel. The operation was carried out in two cases: when the upper blowing lance 4 according to the present invention was employed, and when the conventional hydrocarbon-based refrigerant 8 was not used. The main operating conditions are as shown in Table 1.

The upper blowing lance 4 according to the present invention is a so-called "rubber nozzle" 5 which blows oxygen gas 18 to the lower end and expands.
The sub-nozzles 11 are arranged in two stages at a position 1 m above and separated from each other. The sub-nozzle 11
Six lances are arranged on the outer periphery of the upper blowing lance 4 in each stage. In other words, the six pipes 14 are attached between the outer pipe 10 and the middle pipe 13 of the upper blowing lance 4. The function of the sub-nozzle 11 is different between the upper stage and the lower stage.
１０００1000 μm) and the small nozzle at the bottom is small (80-3
00 μm). Heavy oil was used as the hydrocarbon-based refrigerant 8, and during the operation, blowing was performed through the sub-nozzles 11 at a total supply speed of 30 liters / min for 60 minutes. Was set at 2: 1.

[0020]

[Table 1]

The operation results are summarized in Table 2. From Table 2, it can be seen that when the top-blowing lance 4 according to the present invention is employed, the temperature of the exhaust gas is reduced as compared with the conventional case, and the erosion rate of the furnace mouthpiece 7 and the furnace wall refractory 6 of the reaction vessel is significantly reduced. Is evident. In addition, since CO gas is generated by the thermal decomposition of heavy oil, the calories of the exhaust gas do not decrease more than before,
The secondary combustion was also performed.

[0022]

[Table 2]

The above embodiment relates to the smelting reduction blowing of the molten metal 15 using the converter type reaction vessel 17.
The upper blowing lance 4 according to the present invention may be used for ordinary refining of ordinary molten metal (such as decarburization of molten steel in a converter).

[0024]

As described above, according to the present invention, a different type of refrigerant can be smoothly separated from the oxidizing gas and the cooling water with a relatively simple structure without increasing the size of the conventional triple tube. It can be supplied into the furnace. As a result, the smelting reduction blowing of the molten metal can be performed smoothly.

[Brief description of the drawings]

FIG. 1 is a view showing an example of an upper blowing lance according to the present invention, wherein (a) is a longitudinal section, and (b) is a view taken along the line AA of (a).

FIG. 2 is a view showing a part of a longitudinal section of an upper blowing lance according to the present invention.

FIG. 3 is a view showing a vertical cross section of the upper blowing lance according to the present invention, which is different from FIG. 2;

4A and 4B are diagrams showing an example of an upper blowing lance of a four-tube structure, wherein FIG. 4A is a longitudinal section, and FIG. 4B is a view taken along the line AA in FIG.

FIG. 5 is a view showing an upper lance of a conventional triple tube structure.

FIG. 6 is a view showing a state in which the upper part of a furnace is cooled by a conventional upper blowing lance having a sub-nozzle.

FIG. 7 is a development view of the lance according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flow path of oxidizing gas 2 Supply path of cooling water 3 Drainage path of cooling water 4 Top blowing lance 5 Nozzle (Laval nozzle) 6 Furnace wall refractory 7 Furnace base 8 Other refrigerant (hydrocarbon fluid) 9 Refrigerant Supply channel 10 Outer tube 11 Sub nozzle 12 Inner tube 13 Middle tube 14 Tube 15 Molten metal (hot metal) 16 Sleeve 17 Converter type reaction vessel 18 Oxygen gas (Oxidizing gas) 19 Slag 20 Sub nozzle block 21 Sliding surface

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomoaki Tadama 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Inside the Chiba Works of Kawasaki Steel Corporation (72) Inventor Yuki Nabeshima 1, Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture 4K002 AD02 AD03 BF01 BF03 4K013 CA04 CA12 CA16 CA21 F-term in Kawasaki Steel Corporation Chiba Works

Claims (4)

[Claims] 1. An inner pipe for supplying an oxidizing gas, a middle pipe surrounding the inner pipe, forming a supply path of cooling water for cooling the inner pipe, and an outer pipe forming a drain path of the cooling water. A nozzle for blowing an oxidizing gas into the molten metal held in the converter type reaction vessel, which is attached to a lower end of the inner tube, and a top blowing lance for blowing molten metal, wherein between the outer tube and the middle tube Along with disposing a plurality of pipes that are separated from each other and form a flow path of the hydrocarbon-based refrigerant,
An upper blowing lance for blowing molten metal, wherein a sub-nozzle that opens to the outside of the outer tube and that injects the refrigerant outside the lance is attached to each tube. 2. The upper blowing lance according to claim 1, wherein the sub-nozzles are mounted in a plurality of stages in the longitudinal direction of the lance. 3. The upper blowing lance according to claim 1, wherein the sub-nozzle is fixed to an outer tube and slidably contacts the middle tube. 4. The upper blowing lance according to claim 1, wherein the tube is curved in a longitudinal direction.