TW202020167A - Bottom blowing double tube for converter - Google Patents

Abstract

A bottom blowing double tube for a converter is described. The bottom blowing double tube for the converter includes an outer tube and an inner tube. The outer tube has a pipeline and an inner side surface. The inner tube is disposed within the pipeline, in which the inner tube has a first gas channel and an outer side surface. The inner tube includes various ribs disposed on the outer side surface of the inner tube, and a second gas channel is formed between every two adjacent ribs, the inner side surface of the outer tube, and the outer side surface of the inner tube.

Description

Bottom blowing double tube for converter

The invention relates to a converter steelmaking device, and in particular to a bottom-blown double tube for a converter.

When the molten steel is blown in the converter, the bottom of the converter is generally equipped with a bottom blowing pipe to blow out the gas to the molten steel, thereby stirring the molten steel to make the smelting reaction more rapid and uniform. In the case of smelting high-alloy steel grades, such as stainless steel, or adding a large amount of scrap steel, because more heat sources are required in a short time, in addition to blowing oxygen at the top of the converter toward the molten steel, an additional steel will be used at the bottom of the converter. The method of blowing oxygen.

However, the continuous blowing of gas into the molten steel with the bottom torch will cause the wear near the bottom torch to be faster than other bottom regions. This also means that the life of the converter furnace depends on the bottom blowing area. At present, the most common bottom blowing tube for converter is a single round tube design. Although the bottom blowpipe with a single round tube design is cheap, there is no other cooling design except for the effect of cooling the area near the mouth of the blowpipe when blowing the gas itself, which will make it difficult for protective solids to form on the bottom blowpipe. on.

In order to extend the life of the bottom blowpipe mouth, the bottom blowpipe with double tube design is currently used to replace the bottom blowpipe with single round tube design. The existing double bottom blowing tube for the converter is designed with concentric inner circular tube and outer circular tube, and the inner circular tube passes through the outer circular tube. Generally speaking, the inner tube of the double bottom blowing tube blows oxygen, and the outer tube blows flammable gas. When the flammable gas comes into contact with high-temperature molten steel, it will absorb a large amount of heat and crack it, which can make the temperature around the mouth of the bottom blow pipe fall rapidly, and then the liquid steel can be condensed into solid condensate to protect the bottom blow pipe. Port to reduce the impact of the molten steel driven by the gas on the bottom of the bottom blowpipe.

However, the inner tube will vibrate under the influence of the pressure change when the gas is blown, so that the solid condensate can easily fall off. In addition, the outer surface of the concentric inner tube and the inner surface of the outer tube are smooth surfaces. After the solid condensate is generated, there is almost no base for its stable grasping, which also causes the solid condensate to fall off easily. In this way, the area near the nozzle of the bottom blow pipe cannot be effectively protected.

Therefore, there is an urgent need for a technology that can effectively reduce the loss near the nozzle of the bottom blowpipe to prolong the life of the furnace body of the converter.

Therefore, an object of the present invention is to provide a bottom-blown double tube for a converter. The inner tube includes a plurality of protruding strips disposed on the outer surface thereof. A plurality of combustible gas is formed between the protruding strips and the inner surface of the outer tube Gas channel. With the provision of the convex strip, the cross-sectional area of the inner tube wall can be increased, and the solid condensate of the molten steel can have more bases to be attached, so that the solid condensate is not easily dropped by the scouring of the molten steel. Because the protected solid condensate is maintained at the bottom blowpipe The time near the mouth is extended, so the solid condensate can effectively protect the area near the bottom blowpipe nozzle, and can reduce the loss near the bottom blowpipe nozzle.

Another object of the present invention is to provide a bottom-blown double tube for a converter. The convex strips on the outer side of the inner tube can make the bottom-blown double tube stable to maintain the concentric state of the inner tube and the outer tube, so it can be reduced Vibration of the inner tube caused by high-flow gas injection can reduce the impact on solid condensate.

Another object of the present invention is to provide a bottom-blowing double tube for a converter, which can effectively reduce the loss near the bottom-blowing tube nozzle, thus extending the life of the furnace body and greatly reducing the production cost.

According to the above object of the present invention, a bottom-blown double tube for a converter is proposed. The bottom-blown double tube for this converter includes an outer tube and an inner tube. The outer tube has a pipe and an inner side. The inner tube is arranged in the pipe of the outer tube, wherein the inner tube has a first gas channel and an outer side. The inner tube includes several convex strips arranged on the outer side of the inner tube, and a second gas channel is formed between each two adjacent convex strips, the inner side of the outer tube, and the outer side of the inner tube.

According to an embodiment of the present invention, the cross-sectional shape of the convex strip is rectangular, triangular, circular arc, or elliptical.

According to an embodiment of the present invention, each of the two adjacent convex strips has a spacing, and these spacings are the same as each other.

According to an embodiment of the invention, the number of the above-mentioned convex bars is 5 to 40.

According to an embodiment of the present invention, the distance between the aforementioned convex strip and the inner side of the outer tube is less than or equal to about 0.5 mm.

According to an embodiment of the present invention, the above-mentioned inner tube has a gas inlet end and a gas outlet end opposed to each other, and these protruding strips extend from the gas inlet end to the gas outlet end of the inner tube.

According to an embodiment of the present invention, the inner tube has a gas inlet end and a gas outlet end opposite to each other, the length of the convex strips is less than the length of the inner tube, and the convex strips extend from the gas outlet end of the inner tube toward the gas inlet end extend.

According to an embodiment of the invention, the outer tube and the inner tube are coaxial.

100‧‧‧Bottom blowing double tube

100a‧‧‧Bottom blowing double tube

110‧‧‧Outer tube

112‧‧‧Pipeline

114‧‧‧Inside

116‧‧‧Outside

118‧‧‧ Second gas channel

118a‧‧‧Second gas channel

120‧‧‧Inner tube

120a‧‧‧Inner tube

122‧‧‧The first gas channel

124‧‧‧Inside

126‧‧‧Outside

126a‧‧‧Outside

128‧‧‧Convex strip

128a‧‧‧Convex strip

128g‧‧‧spacing

130‧‧‧Gas inlet

132‧‧‧ gas outlet

d‧‧‧Distance

In order to make the above and other objects, features, advantages and embodiments of the present invention more obvious and understandable, the drawings are described as follows: [FIG. 1] shows a bottom for a converter according to an embodiment of the present invention Three-dimensional schematic view of the double-tube blowing; [Figure 2A] is a schematic cross-sectional view of the bottom-blown double tube for a converter taken along the AA section line of FIG. 1; [FIG. 21B] is a cross-sectional view of the BB section of FIG. 1 A cross-sectional schematic view of a bottom-blown double tube for a converter cut by a line; and [FIG. 3] is a schematic cross-sectional view illustrating a bottom-blown double tube for a converter according to an embodiment of the present invention.

Please refer to FIGS. 1 and 2A, wherein FIG. 1 is a perspective schematic view of a bottom-blown double tube for a converter according to an embodiment of the present invention, and FIG. 2A is a cross-sectional view taken along line AA of FIG. A schematic cross-sectional view of the bottom-blown double tube for the converter. The bottom-blown double tube 100 for the converter is mainly used to blow out the gas to the molten steel when the converter is blowing the molten steel to stir the molten steel, thereby making the smelting reaction proceed uniformly and improve the smelting efficiency.

In this embodiment, the bottom-blown double tube 100 for the converter includes an outer tube 110 and an inner tube 120. The outer tube 110 has a pipe 112 passing therethrough. The outer tube 110 has an inner side 114 and an outer side 116, wherein the inner side 114 defines the shape of the pipe 112 and the outer side 116 defines the outline of the outer tube 110. The outer tube 110 may be a round tube, an elliptical tube, or a polygonal tube, such as a triangular tube, a square tube, or the like. The shape of the tube 112 may be, for example, circular, elliptical, or polygonal. In some exemplary examples, the outer tube 110 is a round tube, and the shape of the tube 112 is circular.

The inner tube 120 is provided in the pipe 112 of the outer tube 110. The inner tube 120 has a first gas passage 122 therethrough. The inner tube 120 also has an inner side 124 and an outer side 126, wherein the inner side 124 defines the shape of the first gas channel 122, and the outer side 126 is adjacent to the inner side 114 of the outer tube 110. The shape of the inner tube 120 preferably matches the shape of the tube 112 of the outer tube 110. Therefore, the shape of the inner tube 120 may be a circle, an ellipse, or a polygon, such as a triangular tube, a square tube, or the like. The shape of the first gas channel 122 in the inner tube 120 may be, for example, circular, elliptical, or polygonal. In some exemplary examples, the inner tube 120 is a round tube, the shape of the first gas channel 122 is circular, and the outer tube 110 and the inner tube 120 are coaxial. The first gas channel 122 of the inner tube 120 may be configured to spray oxygen, nitrogen, or argon gas, for example, to the molten steel.

Please refer to FIGS. 1 and 2A again. The inner tube 120 includes a plurality of convex strips 128. These convex strips 128 are provided on the outer side 126 of the inner tube 120 and extend along the length of the inner tube 120. In some exemplary examples, the convex strips 128 are substantially parallel to each other. A second gas channel 118 is formed between each two adjacent protrusions 128, the inner side 114 of the outer tube 110, and the outer side 126 of the inner tube 120. Each second gas channel 118 is part of the tube 112 of the outer tube 110. For example, the second gas channel 118 may be used to spray inert gas or flammable gas on the molten steel. There is a distance 128g between every two adjacent convex strips 128. In some exemplary examples, these pitches 128g may be the same as each other. In some specific examples, these spacings 128g may not be the same.

As shown in FIG. 1, the inner tube 120 has a gas inlet end 130 and a gas outlet end 132, where the gas inlet end 130 and the gas outlet end 132 may be located at opposite ends of the inner tube 120, respectively. In some examples, each rib 128 may extend from the gas inlet end 130 of the inner tube 120 to the gas outlet end 132, that is, the length of each rib 128 is substantially equal to the length of the inner tube 120.

In some alternative examples, please refer to FIGS. 1, 2A, and 2B, where FIG. 2B is a schematic cross-sectional view of a bottom-blown double tube for a converter taken along the BB section line of FIG. 1. In these examples, the protrusions 128 extend from the gas outlet end 132 of the inner tube 120 toward the gas inlet end 130, but do not extend to the gas inlet end 130. Therefore, the convex strip 128 is located on the outer side 126 of the inner tube 120 section shown in FIG. 2A, but the convex strip 128 does not extend to the outer side 126 of the inner tube 120 section shown in FIG. 2B. Therefore, the length of each convex strip 128 is less than the length of the inner tube 120.

The cross-sectional shapes of these convex strips 128 may be the same as each other. In some specific examples, the cross-sectional shapes of the convex strips 128 may be different from each other, or the cross-sectional shapes of the convex strips 128 are partly the same and partly different. For example, the cross-sectional shape of each convex strip 128 may be rectangular, triangular, circular arc, or elliptical. As shown in the embodiment shown in FIG. 2A, the cross-sectional shape of each convex strip 128 is rectangular, and adjacent convex strips 128 have the same spacing 128g, so that the inner tube 120 has a gear-like structure.

Please refer to FIG. 3, which is a schematic cross-sectional view of a bottom-blown double tube for a converter according to an embodiment of the present invention. The structure of the bottom blowing double tube 100a of this embodiment is substantially the same as the structure of the bottom blowing double tube 100 of the above embodiment. The difference between the two lies in the convex strips provided on the outer side 126a of the inner tube 120a of the bottom blowing double tube 100a The cross-sectional shape of 128a is triangular. In addition, since the cross-sectional shape of the convex strip 128a is different from the convex strip 128 of the bottom-blown double tube 100, in the bottom-blown double tube 100a, every two adjacent convex strips 128a, the inner side 114 of the outer tube 110, and the inner tube The second gas channel 118a formed between the outer side surface 126a of 120a is triangular-like, different from the rectangular-shaped of the second gas channel 118.

Please refer to FIGS. 1 and 2A again. In some exemplary examples, the number of protruding strips 128 provided on the outer side 126 of the inner tube 120 is 5 to 40. In addition, the distance d between each convex strip 128 and the inner side 114 of the outer tube 110 may be substantially less than or equal to 0.5 mm, for example.

By providing a plurality of convex strips 128 on the outer side 126 of the inner tube 120, a second gas channel 118 can be formed between every two adjacent convex strips 128, so that the convex strip 128 and the inner side 114 of the outer tube 110 Gap It is not the main channel for blowing gas, so the distance d between the protruding strip 128 and the inner side 114 of the outer tube 110 can be much smaller than the distance between the inner tube and the outer tube of the conventional concentric double tube. Therefore, the convex strip 128 can stably maintain the inner tube 120 and the outer tube 110 concentrically, which can effectively prevent the vibration of the inner tube 120 caused by the high-flow gas injection, and thus can prevent the nozzle of the double tube 100 being blown at the bottom. The solid condensate of the molten steel in the vicinity falls off due to the vibration of the inner tube 120.

In addition, since the cross-sectional area of the wall of the inner tube 120 is increased due to the design of the protruding strip 128, and the outer tube 110 mainly uses the second gas passage 118 between the protruding strips 128 to spray gas, the solidification of the molten steel After the object is generated, there are more bases that can be attached, and it can be extended on the outer tube 110, the protruding strip 128, and the inner tube 120, thereby not only the adhesion of the solid condensate can be improved, but the solid condensate can be further improved The maintenance force that the inner tube 120 and the outer tube 110 are concentric.

Since high temperature molten metal is difficult to observe, water model simulation experiments are used here. In the water model simulation experiment, liquid nitrogen is used to cool nitrogen, and the cooled nitrogen is used as the bottom blown gas to blow the outer tube into the water to simulate the flammable gas cracking and absorb the heat of the molten steel. The gas in the inner tube is nitrogen at normal temperature. Since the heat will be taken away by the low-temperature nitrogen blown into the water, the water will condense into ice at the mouth of the bottom-blown double tube. Observing the solidified ice of the nozzles of the bottom-blown double tube and the general double circular tube in the embodiment of the present invention, it can be found that the solidified ice of the bottom-blown double tube of the embodiment is larger than that of the general double circular tube. Therefore, it can be confirmed from the results of the water model simulation experiments that the bottom-blown double tubes of the examples are indeed more conducive to the formation and adhesion of solid condensate than the general double round tubes.

It can be seen from the above-mentioned embodiments that one of the advantages of the present invention is that the inner tube of the bottom-blown double tube for the converter of the present invention includes several convex strips. On the outside surface, a plurality of inert gas or combustible gas channels are formed between these convex strips and the inside surface of the outer tube. With the provision of the convex strip, the cross-sectional area of the inner tube wall can be increased, and the solid condensate of the molten steel can have more bases to be attached, so that the solid condensate is not easily dropped by the scouring of the molten steel. Since the time that the protected solid condensate is maintained near the bottom torch nozzle is prolonged, the solid condensate can effectively protect the area near the bottom torch nozzle and reduce the loss near the bottom torch nozzle.

It can be seen from the above-mentioned embodiments that another advantage of the present invention is that the convex strips on the outer surface of the inner tube of the bottom-blown double tube for the converter of the present invention can make the bottom-blown double tube stable to maintain the inner tube and the outer tube. The concentric state can reduce the vibration of the inner tube caused by the high-flow gas injection, and can reduce the impact on the solid condensate.

It can be seen from the above-mentioned embodiments that another advantage of the present invention is that the bottom-blowing double tube for the converter of the present invention can effectively reduce the loss near the bottom-blowing tube orifice, so the furnace life can be extended and the production cost can be greatly reduced.

Although the present invention has been disclosed as above with examples, it is not intended to limit the present invention. Anyone who has ordinary knowledge in this technical field can make various modifications and retouching without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined in the appended patent application.

100‧‧‧Bottom blowing double tube

110‧‧‧Outer tube

112‧‧‧Pipeline

114‧‧‧Inside

116‧‧‧Outside

118‧‧‧ Second gas channel

120‧‧‧Inner tube

122‧‧‧The first gas channel

124‧‧‧Inside

126‧‧‧Outside

128‧‧‧Convex strip

128g‧‧‧spacing

d‧‧‧Distance

Claims (8)

A bottom-blown double tube for a converter, comprising: an outer tube having a pipe and an inner side; and an inner tube provided in the pipe, wherein the inner tube has a first gas channel and an outer side, and The inner tube includes a plurality of convex strips disposed on the outer surface of the inner tube, and every two adjacent convex strips, the inner side of the outer tube, and the outer side of the inner tube form a first Two gas channels. For example, the bottom-blown double tube for the converter applied for in the scope of patent application, wherein the cross-sectional shape of each of these convex strips is rectangular, triangular, circular arc, or elliptical. For example, the bottom-blowing double tube for a converter applied for in item 1 of the patent application, wherein every two adjacent ribs have a pitch, and the pitches are the same as each other. For example, the bottom-blown double tube used in the converter of patent application item 1, the number of these convex strips is 5 to 40. For example, the bottom-blown double tube used in the converter of patent application item 1, wherein the distance between the convex strips and the inner side of the outer tube is less than or equal to 0.5 mm. For example, the bottom-blowing double tube for converters in the scope of patent application item 1, wherein the inner tube has a gas inlet end and a gas opposite to each other At the outlet end, the protrusions extend from the gas inlet end of the inner tube to the gas outlet end. For example, the bottom-blowing double tube for a converter applied for in the patent scope item 1, wherein the inner tube has a gas inlet end and a gas outlet end opposite to each other, the length of the protruding strips is shorter than the length of the inner tube, and the protruding The strip extends from the gas outlet end of the inner tube toward the gas inlet end. For example, the bottom-blown double tube used in converters in the scope of patent application item 1, wherein the outer tube is coaxial with the inner tube.

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