KR102388530B1 - converter exhaust gas treatment device - Google Patents

Abstract

Provided is a converter exhaust gas treatment device that is excellent in durability and is capable of stable vertical movement of a skirt without being affected by dust, slag, metal, etc., and which enables maintenance and improvement of productivity. Converter exhaust for connecting between the converter furnace opening 11 and the hood 20 arranged above the converter furnace opening 11 through the skirt 30 that goes up and down with respect to the converter furnace opening 11 and the hood 20 A gas processing device, wherein the lower end of the inner wall surface of the hood 20 is disposed outside the opening edge of the converter furnace opening 11, and the skirt 30 is disposed so that the upper end thereof surrounds the lower end of the hood 20, The space between the hood 20 and the skirt 30 has an open structure, and a gap of 30 mm or more and 70 mm or less is provided between the hood 20 and the skirt 30 as a minimum width.

Description

converter exhaust gas treatment device

The present invention relates to an exhaust gas treatment apparatus having a connection structure between a hood and a skirt, in which a hood disposed above a converter furnace is connected to a hood disposed above a converter furnace through a skirt that elevates with respect to the converter in an ironworks or the like. is about

For example, in a steelworks etc., when oxygen refining of molten iron|metal in a converter, the exhaust gas of high temperature and high dust which has CO gas as a main component generate|occur|produces abundantly.

In order to recover and process this converter exhaust gas, an exhaust gas cooler is arrange|positioned above the converter furnace opening. However, since the converter needs to tilt with the trunnion shaft of the converter as the center of rotation when molten iron is charged or molten steel is discharged, a fixed exhaust gas cooler cannot be installed within the rotation radius of the converter. For this reason, a vertically movable skirt is usually provided between the converter furnace opening and the hood of a converter exhaust gas treatment facility.

A general structure around a conventional skirt will be described with reference to FIG. 3 . In addition, in FIG. 3 , the left side of the element indicated by the reference numeral 111 corresponds to the center (inside) of the converter, and the right side of the element indicated by the reference numeral 110 corresponds to the outer peripheral side of the converter.

This skirt 130 is provided between the furnace opening 111 of the converter 110 and the hood 120 arrange|positioned above the furnace opening 111. As shown in FIG.

And in order to prevent intake of external air or ejection of exhaust gas between the skirt 130 and the hood 120 , the water sealing water 136 stored in the water sealing jacket 135 integrally formed with the skirt 130 . ), the partition tube 126 installed on the fixed bottom 125 formed integrally with the hood 120 is immersed in the hood 120 to prevent gas leakage from the gap between the skirt 130 and the hood 120 . .

Here, in order to enable the tilting of the converter 110 and to minimize the air gap between the furnace 111 and the hood 120 during oxygen refining of molten iron, the skirt 130 is a driving device such as a hydraulic cylinder It has a structure that can move up and down along the outer periphery of the hood 120 by means of 134 , and even when the skirt 130 moves up and down, the compartment 126 , the water sealing jacket 135 and the water sealing water 136 . It is configured to maintain a water seal by the

In addition, in FIG. 3 , reference numeral 131 denotes a cooling water supply header that supplies cooling water for cooling the skirt 130 , and reference numeral 132 denotes a cooling water drainage header that drains cooling water. Reference numeral 121 denotes a cooling water supply header for cooling water that cools the hood 120 .

However, in this water-sealing structure, dust generated from the furnace during oxygen blowing of the molten iron, slag that is scattered, and molten metal penetrate into the water-sealing jacket 135 and accumulate at the bottom so that the skirt 130 cannot rise to the upper limit position. There is a possibility that this will happen. In the worst case, the skirt 130 cannot rise, so the tilting of the converter 110 containing the molten steel therein is not possible, or a drain pipe (not shown) for draining the water sealing water 136. There is also a risk that water-sealed water leaks under the converter due to breakage of the converter, and high-temperature jets from the furnace furnace come into contact with the puddle of the leaked water-sealed water, resulting in a steam explosion.

Accordingly, various proposals have been made, for example, as disclosed in Patent Documents 1 to 3 for the purpose of discharge and solidification prevention and intrusion prevention of dust, slag, and metal which have penetrated into the water sealing jacket 135 .

For example, the seal structure of the skirt in the converter exhaust gas treatment facility disclosed in patent document 1 is equipped with the skirt of the water cooling structure without a water sealing jacket. The seal structure includes a hood above the converter furnace opening, a seal bottom protruding outward from the hood, a water-cooled or fire-resistant cylindrical wall hanging from the seal bottom, and a sliding gap with the cylindrical wall. and a cylindrical seal plate installed at the upper end of the skirt, and seals between the skirt and the hood by the cylindrical wall and the cylindrical seal plate. Here, it is so preferable that the clearance gap between a cylindrical wall and a cylindrical sealing plate is small, and it is considered preferable to ensure the height of a contact surface 200 mm or more.

Further, in Patent Document 2, a nozzle for jetting washing water containing gas bubbles into the seal jacket is disposed at the bottom of the seal jacket, and a swirling flow is formed in the seal water by means of water or a gas ejection nozzle, and the seal water A method of preventing the deposition of dust or slag by blowing a gas into it and stirring it is proposed.

In Patent Document 3, the horizontal distance from the furnace mouth edge of the converter to the pitch circle of the water pipe wall of the skirt is 400 mm or more and 500 mm or less, and the lower end of the water pipe of the hood is below the line connecting the furnace mouth and the inner upper end of the seal jacket. A method characterized in that there is proposed.

Japanese Patent Laid-Open No. 2007-302932 Japanese Patent Laid-Open No. 2007-262525 Japanese Patent Laid-Open No. 2014-077153

However, in Patent Document 1 described above, there was a fear that the skirt body could not be lifted or lowered due to the insertion of slag or slag into the gap between the cylindrical wall and the cylindrical seal plate or thermal deformation of the non-water-cooled cylindrical seal plate. In addition, the current situation is that there is a problem such as poor durability has not been put to practical use.

Moreover, in patent document 2, the effect is not enough, and it cannot avoid periodically stopping operation of a converter and cleaning a seal jacket, but the fall of productivity is brought about.

Moreover, in patent document 3, since it is not a method which eliminates the dust accumulation|stacking to the bottom part of a seal jacket, since it is it, it is required to clean the accumulated dust.

As described above, in the sealing method of the water sealing system, there was a problem in that it was not possible to prevent the accumulation of dust or the like in the sealing jacket, and thus a decrease in productivity accompanying cleaning the sealing jacket was unavoidable.

On the other hand, it is the present situation that sealing methods other than a water sealing method have not yet been put to practical use from problems, such as durability.

The present invention has been made in view of the above situation, has excellent durability, and is capable of stable vertical movement of the skirt without being affected by dust, slag, metal, etc. An object of the present invention is to provide an exhaust gas treatment device.

In order to solve the above problem, the present inventors diligently studied and analyzed the flow of gas discharged from the converter furnace. As a result, a gap is provided between the hood and the skirt without providing a seal structure between the hood and the skirt, and the inside of the hood Even if the furnace is connected to the outside air, the inflow of outside air into the converter and The effect of suppressing the outflow of gas in a converter aerodynamically was acquired, and the knowledge that suction of the outside air in between a skirt and a hood and the ejection of exhaust gas can fully be suppressed was acquired.

The present invention has been made based on the above findings, and a converter exhaust gas treatment apparatus according to the present invention includes a hood disposed above a converter furnace opening, and a skirt that can be moved up and down with respect to the converter furnace opening under the hood. A converter exhaust gas treatment apparatus, wherein the hood has a lower end of its inner wall surface located outside an opening edge of the converter furnace when viewed from the top, that is, when viewed from above a centerline of the hood, the skirt having an upper end It is disposed to surround the lower end of the hood, and between the hood and the skirt, a gap for communicating the inside of the hood with the outside air is provided, and has a structure in which the inside of the hood is opened to outside air. And the converter exhaust gas processing apparatus which concerns on this invention is made into the range which the minimum width of the said clearance gap is 30 mm or more and 70 mm or less, It is characterized by the above-mentioned.

According to the converter exhaust gas treatment apparatus according to the present invention, since the structure between the hood and the skirt is an open structure without a sealing mechanism, it is not affected by dust, slag, metal, etc. like the water sealing method. Also, there is no problem of durability like other sealing methods.

In the hood, the lower end of the inner wall surface as viewed from the top is arranged outside the opening edge of the converter furnace, and the skirt is arranged so that the upper end surrounds the outside of the lower end of the hood, the hood and the Between the skirts, a gap is provided for communicating the inside of the hood with the outside air. This gap is provided so that the minimum distance between the said hood and the said skirt may become 30 mm or more and 70 mm or less. By setting the minimum value of the clearance between the hood and the skirt within such a range, an aerodynamic action occurs, and it becomes possible to sufficiently suppress the intake of external air and the ejection of exhaust gas between the skirt and the hood.

Here, in the converter exhaust gas processing apparatus of this invention, it is preferable that the overlapping length of the said hood and the said skirt is in the range of 135 mm or more and 400 mm or less.

In this case, since the overlapping length of the hood and the skirt in the vertical direction is within the range of 135 mm or more and 400 mm or less, it is possible to further sufficiently suppress the intake of external air and the ejection of exhaust gas between the skirt and the hood. .

Further, in the converter exhaust gas treatment apparatus of the present invention, it is preferable that an inclined surface portion having an inclination angle equal to or greater than the angle of repose of dust generated during oxygen refining of molten iron in the converter is formed on the outer peripheral surface of the skirt.

In this case, it can suppress that the dust which generate|occur|produces when oxygen refining of the molten iron|metal of a converter adheres to the outer peripheral surface of a skirt and accumulates.

Moreover, in the converter exhaust gas treatment apparatus of this invention, it is preferable that the said skirt is equipped with the skirt main body, and the refractory body construction body arrange|positioned on the outer peripheral side of this skirt main body.

In this case, since the skirt main body and the refractory body construction body arrange|positioned on the outer peripheral side of this skirt main body are provided, it becomes possible to suppress thermal deterioration of a skirt main body by a refractory body construction body.

Moreover, in the converter exhaust gas processing apparatus of this invention, it is preferable that the said skirt main body and the said refractory construction body have a divided structure.

In this case, since the skirt body and the refractory construction body have a divided structure, damage to the refractory construction body can be suppressed even when the skirt body is thermally expanded.

Further, in the converter exhaust gas treatment apparatus of the present invention, it is preferable that the skirt includes a skirt body and a water cooling structure disposed on the outer peripheral side of the skirt body.

In this case, since the skirt body and the water-cooling structure disposed on the outer peripheral side of the skirt body are provided, the water-cooling structure can sufficiently cool the skirt body, thereby suppressing thermal deterioration of the skirt body.

Further, in the converter exhaust gas treatment apparatus of the present invention, it is preferable that the skirt body and the water cooling structure have a divided structure.

In this case, since the skirt body and the water cooling structure have a divided structure, it is possible to suppress damage to the refractory body construction body even when the skirt body thermally expands.

As described above, according to the present invention, the converter exhaust gas treatment that has excellent durability and enables stable vertical movement of the skirt without being affected by dust, slag, metal, etc. device can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic explanatory drawing of the converter exhaust gas processing apparatus which is embodiment of this invention.
FIG. 2 is an explanatory diagram showing an example of a connection structure between a hood and a skirt in the converter exhaust gas processing apparatus according to the embodiment of the present invention.
3 is an explanatory view showing an example of a connection structure between a hood and a skirt in a conventional converter exhaust gas treatment apparatus having a water sealing structure.

EMBODIMENT OF THE INVENTION Hereinafter, the converter exhaust gas processing apparatus which is embodiment of this invention is demonstrated with reference to attached drawing. In addition, this invention is not limited to the following embodiment.

Fig. 1 shows a schematic configuration diagram of a converter exhaust gas processing apparatus 1 according to the present embodiment.

The converter exhaust gas treatment device 1 includes a hood 20 positioned above the converter 10 , a skirt 30 connecting the converter 10 and the hood 20 in a sealed state, and a converter 10 . ), an exhaust gas cooler 2 for cooling the exhaust gas, and a primary dust collector 3 and a secondary dust collector 4 for removing dust from the cooled exhaust gas. In addition, various gas processing devices are arranged on the downstream side of the secondary dust collector 4 .

And the damper 5 which controls the furnace-aperture pressure in the hood 20 is arrange|positioned in the secondary dust collector 4 . The furnace mouth pressure is measured using a pressure detection stage 23 . In addition, although the said pressure detection stage 23 is provided in the hood 20 in FIG. 2, you may provide in the exhaust gas cooler 2 also.

Here, the connection structure of the hood and the skirt in the converter exhaust gas processing apparatus which is embodiment of this invention is shown in FIG. In addition, in FIG. 2, the left side corresponds to the center part (inside) of a converter, and the right side corresponds to the outer peripheral side of a converter.

As shown in FIG. 2, the connection structure of the hood and skirt in the converter exhaust gas processing apparatus which is this embodiment is above the furnace opening 11 of the converter 10 which supplies oxygen gas and refines molten iron|metal. A hood 20 of the converter exhaust gas treatment device 1 for recovering exhaust gas generated from the converter 10 by refining is provided. The hood 20 has a water cooling structure, and is internally cooled by cooling water supplied from the cooling water supply header 21 . The cooling water drain header of the hood 20 is provided above the hood 20 , but is omitted in FIG. 2 .

The hood 20 and the seal bottom 8 are sealed with CO gas through a sand seal, but are omitted in FIG. 2 .

In addition, the cooling water to the water pipe of the skirt 30 penetrates the CO gas seal part of the seal bottom 8 and is supplied by a water supply and drain pipe (not shown).

Between the furnace mouth 11 and the food|hood 20, the skirt 30 which can move up and down is provided over the whole outer peripheral direction of the food|hood 20. As shown in FIG. A cooling water supply header 31 is provided at an end of the skirt 30 on the lower side in the vertical direction, and a cooling water drain header 32 is provided at an end of the skirt 30 at an upper side in the vertical direction.

The cooling water supply header 31 is connected to a cooling water supply pipe (not shown), and the cooling water drainage header 32 is connected to a cooling water drainage pipe (not shown).

That is, the skirt 30 is internally cooled by the cooling water supplied through the cooling water supply pipe, and the cooling water after cooling the skirt 30 is drained through the cooling water drain pipe.

The skirt 30, the coolant water supply pipe, and the coolant drain pipe are integrally formed, and all of the skirt 30, the coolant water supply pipe and the coolant drain pipe are connected to the skirt 30 by a driving device (not shown) such as an electric motor or hydraulic cylinder. ) is installed in the gap with the hood 20 and has a structure to move up and down from above the furnace hole 11 .

Here, a sealing mechanism is not provided between the hood 20 and the skirt 30, so the space outside the furnace mouth 11 side with the hood 20 and the skirt 30 as a boundary (hereinafter simply referred to as "external air") ), and a gap having a minimum width of 30 mm or more and 70 mm or less is provided between the hood 20 and the skirt 30.

Moreover, in this embodiment, it is preferable that the overlap length L of the perpendicular direction from the lower end 20a of the hood 20 to the upper end 30b of the skirt 30 is in the range of 135 mm or more and 400 mm or less.

In addition, in this embodiment, the skirt 30 is provided with the skirt main body 35 and the refractory body construction body 36 arrange|positioned on the outer peripheral side of this skirt main body 35. As shown in FIG.

Moreover, this refractory body construction body 36 is provided on the support structure 34 of the skirt 30. As shown in FIG.

The refractory construction body 36 disposed on the outer periphery side of the skirt 30 is formed with an inclined surface at an angle at which dust generated in the converter 10 and flying matter from the converter 10 are difficult to accumulate. Even in the upper part of the drain header 32, adhesion and deposition of dust generated in the furnace and flying objects from the inside of the furnace are prevented.

The refractory body construction body 36 can be formed by, for example, an inflow or blow-out construction of an alumina-based irregular refractory material or a magnesia-based irregular refractory material.

Moreover, in this embodiment, the skirt 30 is equipped with the skirt main body 35 and the refractory body construction body 36 as mentioned above, The structure in which these skirt main body 35 and the refractory body construction body 36 were divided. is made of

In the converter exhaust gas treatment apparatus of this embodiment having the above-described configuration, a high-temperature and high-content exhaust gas mainly composed of carbon monoxide gas generated during the oxygen refining process of molten iron is recovered as follows.

After the start of oxygen refining of molten iron, the furnace mouth pressure measured through the pressure detection stage 23 after the skirt 30 is lowered to the vicinity of the lower limit position is set to the secondary dust collector 4 of the converter exhaust gas treatment device 1 . By controlling the static pressure of 0 Pa or more and about 30.0 Pa or less with respect to the pressure of outside air by the damper 5 or furnace nozzle pressure control device (not shown) of The ejection of exhaust gas generated from the converter 10 from the gap between 20 ) and the skirt 30 is minimized, so that it is possible to recover a high concentration of CO gas.

According to the present invention, as described above, when the inside of the hood 20 is at a positive pressure in the range of 0 Pa to about 30.0 Pa with respect to the pressure of the outside air, the hood 20 and the The ejector effect generated in the gap between the skirt 30 and the pressure in the hood 20 are almost balanced, so that ejection from the gap between the hood 20 and the skirt 30 is minimized.

While the inner wall surface of the hood 20 is located on the outer peripheral side rather than the opening edge of the converter furnace opening 11, the skirt 30 is further arranged so as to surround the outer peripheral side of the hood 20, and the hood 20 and the skirt (30) The clearance between the hood 20 and the skirt 30 is adjusted so that the distance (symbol cl) between the hood 20 and the skirt 30 at the point where the space is narrowest is 30 mm or more and 70 mm or less. By providing, it becomes possible to sufficiently suppress the intake of external air and the ejection of exhaust gas between the skirt 30 and the hood 20 .

When the minimum distance (symbol cl in FIG. 2 ) between the hood 20 and the skirt 30 is less than 30 mm, the flow of exhaust gas flowing into the exhaust gas cooler 2 from the furnace hole 11 through the hood 20 . The aerodynamic effect generated by It becomes easier to flow into the inner space. In addition, a sufficient gap cannot be secured due to dust or the like generated from the converter, so that vertical movement of the skirt becomes impossible.

In addition, when the minimum distance between the hood 20 and the skirt 30 is more than 70 mm, a part of the exhaust gas rising from the furnace hole 11 is prevented from flowing out from the gap between the hood 20 and the skirt 30 to the outside air. it gets easier

According to the converter exhaust gas treatment apparatus of this embodiment having the above configuration, no sealing mechanism is provided between the hood 20 and the skirt 30 and thus an open structure is obtained. .

In addition, in the state in which the converter exhaust gas processing apparatus of this embodiment is operating, the overlap length between the lower end 20a of the hood 20 and the upper end 30b of the skirt 30 is within the range of 135 mm or more and 400 mm or less. In this case, it becomes possible to further sufficiently suppress the intake of external air or the ejection of exhaust gas between the skirt 30 and the hood 20 .

In the converter exhaust gas treatment apparatus of the embodiment shown in FIG. 2 , the outer peripheral wall of the hood 20 is formed substantially vertically, and the skirt 30 moves vertically along the outer peripheral wall of the hood 20 in parallel. do. When the converter exhaust gas treatment apparatus is operated with the skirt 30 as the lowest position, the overlapping length between the lower end 20a of the hood 20 and the upper end 30b of the skirt 30 (symbol L in FIG. 2 ) is , it is preferable that the skirt be 135 mm or more and 400 mm or less in the vertical direction in the lowest position.

In addition, in this embodiment, on the outer peripheral surface of the skirt 30, it has an inclined surface portion with an inclination angle greater than or equal to the threshold angle (referred to as "dust angle of repose") through which dust generated during oxygen refining of molten iron in the converter 10 slides. When the refractory construction body 36 is formed, it can suppress that the dust which generate|occur|produces at the time of oxygen refining of the molten iron|metal of the converter 10 adheres to the outer peripheral surface of the skirt 30, and accumulates.

Moreover, in this embodiment, when the skirt 30 is equipped with the skirt main body and the refractory body construction body 36 arrange|positioned on the outer peripheral side of this skirt body, this refractory body construction body 36 uses this skirt main body. It becomes possible to suppress the thermal deterioration of

Moreover, in this embodiment, when it is set as the structure in which the skirt main body and the refractory body construction body 36 were divided, it can suppress that the refractory body construction body 36 is damaged even if it is a case where the skirt main body thermally expands.

As mentioned above, although the converter exhaust gas processing apparatus which is an embodiment of this invention was demonstrated concretely, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical spirit of the invention.

In this embodiment, although demonstrated as what provided the refractory body construction body on the outer peripheral side of a skirt, it is not limited to this, You may arrange|position a water cooling structure instead of a refractory body construction body. Also in the case of disposing the water cooling structure, it is preferable to have the inclined surface portion having an inclination angle equal to or greater than the angle of repose of dust generated during oxygen refining. Moreover, it is preferable to set it as the structure in which the skirt main body and the water cooling structure were divided|segmented.

Moreover, it may be comprised only with the skirt body which consists of water cooling piping without arranging a refractory body construction body and a water cooling structure.

Example

Hereinafter, in order to confirm the effect of this invention, in the converter exhaust gas processing apparatus of this invention, the result of performing the flow analysis of converter exhaust gas is demonstrated.

As shown in Table 1 by using the converter exhaust gas treatment apparatus shown in Fig. 1, in the connection structure of the hood and skirt shown in Fig. 2, the positional relationship between the converter furnace opening and the hood and the skirt is variously set, and the present invention Connection structures of the hoods and skirts of Honors 1 to 7 and Comparative Examples 1 to 13 were produced.

And gas flow analysis was performed by changing the furnace-aperture pressure with respect to Invention Examples 1-7 and Comparative Examples 1-13. The results are shown in Table 1.

The "exhaust gas ejection amount" in Table 1 is the amount of exhaust gas recovered into the gas cooler 2 (Z) (m3N/h) and the amount of exhaust gas ejected from the gap between the furnace port 11 and the skirt 30 (X) (m3N/h), and the amount of outside air sucked in from the gap between the hood 20 and the skirt 30 or the amount of exhaust gas blown out (Y) (m3N/h) by analysis, respectively, calculated by the following formula It is a value calculated by 1. In addition, in the ejection amount column of exhaust gas, "+" indicates ejection, and "-" indicates intake.

Exhaust gas ejection amount (%)=Y/(X+Y+Z) … Equation 1

In Comparative Examples 1 and 2, the connection structure of the hood and the skirt (hereinafter, the “connection structure between the hood and the skirt” is simply referred to as the “connection structure”) had an inner diameter of the converter furnace smaller than the inner diameter of the lower end of the hood, and the inner diameter of the hood and skirt. The minimum value of the gap is less than 30 mm. In the case of such a structure, the intake amount of outside air from the gap between the hood 20 and the skirt 30 is large, and when the furnace mouth pressure is 25.5 Pa, the ejection amount (%) of exhaust gas reaches -5.0%. On the other hand, in the connection structure of Examples 1 and 2 of this invention, the ejection amount (%) of exhaust gas remains less than -5.0% even if the furnace-aperture pressure is 25.5 Pa.

In the connection structure of Comparative Examples 3 and 4, the inner diameter of the converter furnace is smaller than the inner diameter of the lower end of the hood, and the minimum value of the gap between the hood and the skirt is more than 70 mm. In the case of such a structure, the ejection amount of exhaust gas from the clearance gap between the hood 20 and the skirt 30 is large, and when the furnace mouth pressure is 25.5 Pa, the ejection amount (%) of exhaust gas exceeds 5.0%. In contrast, in the connection structures of Examples 6 and 7 of the present invention, the ejection amount (%) of the exhaust gas remains less than 5.0% even when the furnace-aperture pressure is 25.5 Pa.

In the connection structures of Comparative Examples 5 to 13, in which the inner diameter of the converter furnace is larger than the inner diameter of the lower end of the hood, under the condition that the furnace furnace pressure (Pa) is equal, the minimum distance between the hood and the inner wall of the skirt (“hood in Table 1”) and the minimum value of the gap between the skirt and the skirt") was enlarged, the amount of exhaust gas ejected from the gap between the hood 20 and the skirt 30 increased. Moreover, it is confirmed that the ejection amount of the said exhaust gas is increasing as the furnace-aperture pressure becomes high. In this way, in the connection structures of Comparative Examples 5 to 13, in which the inner diameter of the converter furnace opening is larger than the inner diameter of the lower end of the hood, the effect of aerodynamically suppressing the inflow of external air into the converter and the outflow of gas in the converter is at least clearly found. can't

On the other hand, in Examples 1 to 7 of the present invention in which the inner diameter of the converter furnace is smaller than the inner diameter of the lower end of the hood, the minimum distance between the hood and the skirt is set to 30 mm to 70 mm, whereby the hood 20 and the skirt 30 The ejection amount of exhaust gas from the gap between them is suppressed to less than ±5.0%. In particular, in the connection structures of Examples 3 to 5 of the present invention, the inflow of external air into the converter to the outflow of gas in the converter is changed by changing the furnace nozzle pressure, and the amount of exhaust gas ejected is less than ±2.0%, so the hood is removed from the furnace opening. The effect of the present invention of utilizing the aerodynamic action of the gap between the hood and the skirt and the flow of exhaust gas introduced into the exhaust gas cooler through the hood is clearly shown.

In view of the above, according to the example of the present invention, it is installed between the converter furnace and the hood above the furnace, and is installed to prevent the outflow of the exhaust gas to the outside air and the entrainment of the outside air into the exhaust gas during oxygen refining of molten iron. The structure of the gap between the skirt and the hood used is water sealed to enable stable vertical movement of the skirt without being affected by dust, slag, or metal, and to reduce maintenance and improve productivity. It was confirmed that it was possible to provide a skirt structure without teeth.

10: converter
11: Nogu
20: hood
30: skirt
35: skirt body
36: refractory material construction body

Claims (7)

A converter exhaust gas treatment apparatus comprising: a hood disposed above a converter furnace opening; and a skirt capable of moving up and down with respect to the converter furnace opening in a lower portion of the hood;
In the hood, the lower end of the inner wall surface is disposed outside the opening edge of the converter furnace when viewed from the top,
The skirt is disposed so that its upper end surrounds the lower end of the hood,
Between the hood and the skirt, a gap is provided for communicating the inside of the hood with the outside air,
The minimum width of the gap is 30 mm or more and 70 mm or less,
The converter exhaust gas treatment apparatus characterized by controlling the pressure of the said converter furnace by the static pressure of 0 Pa or more and 30.0 Pa or less with respect to the pressure of external air. According to claim 1,
The converter exhaust gas treatment apparatus characterized in that the overlapping length of the said hood and the said skirt is in the range of 135 mm or more and 400 mm or less. 3. The method of claim 1 or 2,
A converter exhaust gas treatment apparatus, characterized in that an inclined surface portion having an inclination angle greater than or equal to an angle of repose of dust generated during oxygen refining of molten iron in a converter is formed on an outer peripheral surface of the skirt. 3. The method of claim 1 or 2,
A converter exhaust gas treatment apparatus, wherein the skirt includes a skirt body and a refractory construction body disposed on an outer peripheral side of the skirt body. 5. The method of claim 4,
The converter exhaust gas treatment apparatus, characterized in that the skirt body and the refractory construction body have a divided structure. 3. The method of claim 1 or 2,
The converter exhaust gas treatment apparatus according to claim 1, wherein the skirt includes a skirt body and a water-cooling structure disposed on an outer periphery of the skirt body. 7. The method of claim 6,
The converter exhaust gas treatment apparatus according to claim 1, wherein the skirt body and the water cooling structure have a divided structure.

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