JPH065406Y2 - Converter blowing lance - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a converter blowing lance, and in particular, enables secondary combustion efficiently while adjusting the oxygen flow rate for secondary combustion to protect the furnace. It's about Lance.

<Prior Art> What characterizes the in-reactor reaction in the converter is the agitation and rapid reaction of the steel bath generated by the oxygen jet supplied from the upper blowing lance. The high-purity, high-energy gaseous oxygen flow causes a gas-steel bath reaction represented by a decarburization reaction at the fire point and promotes slag formation of lime, and a slag such as a dephosphorization reaction.
The reaction between the steel baths proceeds simultaneously.

When the hot metal content rate of the converter raw material was as high as around 95%, C in the hot metal was sufficient as a heat source for raising the temperature of the molten steel, but the hot metal content rate was lowered and the content of scrap or iron ore was mixed. If the ratio is increased, it becomes necessary to compensate the heat source for raising the temperature of molten steel in some way.

As this method, so-called secondary combustion in which CO gas generated by decarburization at the time of blowing is burned by oxygen injected from a nozzle different from that for blowing and is transferred to a steel bath together with a method of adding carbonaceous materials such as coke There is a law.

Various proposals have been made for this oxygen injection lance for secondary combustion, but the purpose is to provide a secondary combustion oxygen injection secondary nozzle in addition to the conventional blowing oxygen injection primary nozzle. For example, Japanese Patent Laid-Open No. 62-161911 is disclosed.

As shown in FIG. 2, in addition to the refining main nozzle 2 communicating with the flow passage 1 of the lance body 10, a plurality of secondary combustion auxiliary nozzles 3 are arranged at the tip of the lance body 10. is there. The main nozzle 2 has an angle θ ₀ outward with respect to the lance axis.
In contrast to the normal Laval shape, the sub-nozzle 3 has a flow passage arranged at an angle outward with respect to the lance axis, and the jetted oxygen gas has a subsonic velocity. As described above, the small-diameter flow passage 3a is widened to the large-diameter flow passage 3b. Reference numeral 4 is a water cooling passage provided in the lance body 10.

By forming the sub-nozzle shape as described above, the flow velocity of the ejected oxygen gas is reduced to a subsonic speed, and the CO combustion rate generated in the furnace is increased without damaging the converter furnace opening portion. It increases scrap.

<Problems to be Solved by the Invention> As shown in FIG. 2, in addition to the main nozzle 2, the lance body 10 is provided with a sub-nozzle 3 having a divergent shape including a small diameter passage 3a and a large diameter passage 3b. In order to make the flow rate of the oxygen gas ejected from the sub-nozzle 3 subsonic, it is necessary to provide a plurality of large-diameter sub-nozzles 3, and inevitably the tip diameter D of the lance body 10 is a normal type sub-nozzle. It will be bigger than the one without.

The thickened oxygen lance with a large outer diameter D at the tip of the lance body 10 has an inverse taper to that of a conventional tapered oxygen lance, so that metal splashes on the outer peripheral surface due to splash during converter operation. As it is easy to accumulate and requires removal work, it not only hinders the normal continuous converter operation, but also requires modification of the lance socket part for inserting the oxygen lance and the lance lifting device. was there.

The present invention solves the problems of the conventional oxygen lance having a secondary combustion secondary nozzle 3 in addition to the main nozzle 2 shown in FIG. 2 and increases the outer diameter of the tip of the lance body 10. However, the outer diameter of the lance body was obtained as a result of various examinations so as to correspond to the outer diameter of the tip portion of the oxygen lance without the secondary nozzle of the normal type secondary combustion.

<Means for Solving the Problems> The structure of the present invention for solving the above problems will be described below with reference to FIG. 1 corresponding to the embodiment.

The present invention is directed to a converter blowing lance 10 having a sub-nozzle 3 having a divergent shape so that the ejection speed becomes a subsonic speed in addition to the main refining nozzle 2 and the main nozzle 2 or the main nozzle 2 and the sub nozzle. 3, the flow passage 2a from the inlet portion to the central region is parallel to the lance axis Y, and the flow passage 2b from the central region to the discharge portion has an angle θ ₀ with respect to the lance axis Y in the outward direction. It is constructed by refracting.

<Operation> As shown in FIG. 1, the present invention uses the main nozzle 2 in which the flow passage 2a from the inlet to the central area is parallel to the lance axis Y, and the flow passage 2b from the central area to the discharge area is the lance. It is refracted outwardly at an angle θ ₀ with respect to the axis Y.

Therefore, in comparison with the outer diameter D of the conventional main nozzle 2 shown in FIG. 2 in which the flow path extending from the inlet portion to the discharge portion through the central region is directed outward with an angle θ ₀ with respect to the lance axis Y. Then, in the present invention, the outer diameter of the tip portion of the lance body 10 can be reduced by the dimension w shown in FIG. 2, and the outer diameter D ₀ can be made to correspond to the outer diameter of the one without the secondary combustion auxiliary nozzle.

In FIG. 1, only the main nozzle 2 is shown to be parallel to the lance axis Y from the inlet portion to the central portion area and bent outward from the central portion area to the discharge portion at an angle θ ₀ . If necessary, the secondary combustion sub-nozzle 3 may also have a curved flow path having a shape similar to that of the main nozzle 2.

Further, in FIG. 1, the main nozzle 2 and the sub nozzle 3 are the lance body 10
The structure is shown in which the flow path 1 is connected to the flow path 1 of the lance body. It is also possible to completely separate even the parts and control the oxygen gas flow rate independently of each other, and this is the preferred structure for converter operation.

<Embodiment> The present invention will be described below based on an embodiment shown in the drawings.

In FIG. 1, the main nozzle 2 has an introduction portion flow rate 2a parallel to the lance axis Y and an enlarged taper portion flow path 2b at an angle θ ₀ =.
The secondary nozzle 3 was refracted outwardly at 12 °, while the sub-nozzle 3 had a shape that spreads from the small-diameter flow passage 3a to the large-diameter flow passage 3b, in which four holes were alternately arranged.

In a 150t converter, the oxygen amount from the main nozzle of the oxygen lance of the present invention is 500Nm ³ / min, the oxygen amount from the auxiliary nozzle is 120Nm ³ / min,
As a result of operating at a lance height of 2 m during blowing, the blowing time and metallurgical effect can be the same as when using the conventional oxygen lance shown in Fig. 2, with a secondary combustion rate of 30%, It was possible to achieve a secondary combustion effect with a heat transfer rate of 60%. This operation effect is a good result equivalent to a 7% increase in the scrap blending ratio.

<Effects of the Invention> The present invention having the above-described configuration has the following effects.

1. Even if the same number of secondary nozzles as the main nozzle are provided, the tip of the lance can have the same outer diameter as the conventional one.

2. Even if the main nozzle is bent in the axial direction, if the discharge angle is the same as the conventional one, the same metallurgical effect as the conventional one can be obtained, and the operating conditions are not disturbed at all.

3. Existing lances, lance lifting devices, lance sockets of converter hoods, and other lance-related equipment can be used without modification.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional example. 1 ... Lance body flow path, 2 ... Refining main nozzle, 3 ... Secondary combustion auxiliary nozzle, 4 ... Water cooling passage, 10 ... Lance body.

Claims (1)

[Scope of utility model registration request] 1. A converter blowing lance having a sub-nozzle, which has a divergent shape so that the ejection speed is a subsonic speed, in addition to the main refining nozzle, and the main nozzle or the main nozzle and the sub-nozzle have inlet portions. The flow path from the central area to the central area is parallel to the lance axis, and the flow path from the central area to the discharge area is bent outward at an angle with respect to the lance axis. Lance for converter blowing.