JP4757960B2 - Blast furnace morning glory structure and design method thereof - Google Patents

Description

The present invention relates to a blast furnace morning glory structure and a design method thereof.
This application claims priority on 2009/09/29 based on Japanese Patent Application No. 2009-224434 for which it applied to Japan, and uses the content here.

Conventionally, the morning glory portion of a blast furnace has an iron skin, a cooling stave (hereinafter simply referred to as a stave) provided inside the iron skin, and a refractory brick provided inside the stave to protect the stave. It is equipped with. A castable or the like is appropriately filled between the iron skin and the stave.
With the operation of the blast furnace, wear of the internal structure occurs in the morning glory described above. First, the refractory bricks are worn and then the stave is eroded. As the wear of the stave progresses, it becomes impossible to protect the iron skin, and the morning glory part of the blast furnace reaches the end of its life due to deformation and cracks caused by the temperature rise of the iron skin.

In the blast furnace, operation management is performed so that an appropriate operation state can be obtained while considering a huge number of parameters. However, in many blast furnaces, there is a large fluctuation in operation results during the cost of one furnace, that is, about 15 years. In particular, it is known that a period in which the operation results greatly decline appears in the period of several years from the start of operation after blast furnace burning.
Such a decrease in the operation results of the blast furnace is thought to be due to wear of structures such as refractory bricks on the inner surface of the blast furnace and the profile of the inner surface of the furnace changing with the operation after the firing.
That is, in the initial operation state immediately after the blast furnace is fired, the shape of the furnace inner surface is defined by the surface of the refractory bricks stacked inside the furnace. As time passes from the start of operation of the blast furnace, local wear of the refractory bricks proceeds. Thereby, the profile (contour shape appearing in the vertical cross section) of the furnace inner surface is not appropriate, and the circumferential balance (circumferential shape appearing in the horizontal cross section) may be uneven. In such a state where the surface shape in the blast furnace is inappropriate, the gas flow in the furnace, the distribution of contents, and the like become unstable, which causes a decrease in operation results.

After such an unstable period, the period of stable blast furnace operation continues. This is considered to be because most of the refractory bricks disappear, and a substantially appropriate profile or circumferential balance close to the initial stage of firing is obtained by the deposit layer generated on the surface of the stave furnace.
From the blast furnace firing to the stable operation period, most of the refractory bricks installed inside the blast furnace disappear due to thermal shock and wear. However, it is considered that a deposit layer due to the charge is generated on the stave surface inside the furnace, and this deposit layer compensates for a worn part of the inner surface of the furnace (cell flying effect).
Among the blast furnaces, the inside surfaces of the morning glory and the belly of the furnace have a high-temperature cohesive zone (softening and melting of the ore in the charge begins, and the ores in the semi-molten state are fused together to form a plate. Because it is in contact with the root of the connected area), it is subject to wear due to high heat. That is, when the root portion of the cohesive zone comes into contact with the stave body, a thermal load and wear are generated on the stave body. The deposits generated on the surface of the stave in the blast furnace during the stable operation period of the blast furnace have a protective action against the thermal load and wear, and repair the loss portion of the refractory brick in the furnace. If it is possible to maintain an appropriate deposit layer thickness and in-furnace profile by this repair, it is believed that further long-term stable operation and longer life of the blast furnace can be achieved.

Patent Document 1 is known as a technique for avoiding the inappropriateness of the profile or circumferential balance of the inner surface of the furnace due to the damage of the refractory brick of the blast furnace as described above. According to Patent Document 1, no refractory bricks are installed on the inner surface of the stave, and the inner wall of the stave itself is used as the furnace wall, so that the change in the shape of the furnace inner surface due to wear of the refractory bricks does not occur. Is described.
Patent Document 2 describes that a cooling member is installed near the tuyere in order to positively induce deposits generated on the stave surface.
According to these techniques, by omitting the refractory brick inside the stave, it is possible to avoid a rapid change in the furnace inner surface shape due to the wear of the refractory brick after the blast furnace is fired until the stable operation period. And even if there is no refractory brick by the induction | guidance | derivation of a deposit | attachment, the abrasion of a stave can be suppressed.

Japanese Unexamined Patent Publication No. 2002-115007 Japanese Unexamined Patent Publication No. 2005-194567

However, in Patent Documents 1 and 2, it is difficult to stably generate the in-furnace surface shape formed by the adhering layer on the stave surface for a long period of time in the height direction and the circumferential direction of the blast furnace. In addition, the profile in the blast furnace changes due to changes in charge and operating conditions during blast furnace operation. In particular, when the circumferential balance of the inner surface profile of the furnace in the blast furnace direction changes, the stable operation of the blast furnace is hindered, causing a decrease in productivity.
Moreover, in the structure of the blast furnace which does not install a refractory brick inside a stave like the structure of patent document 1, a stave and an iron skin are rapidly heated from normal temperature to about 1500 degreeC-2000 degreeC at the time of the blast furnace firing. . For this reason, the stave may be damaged by a heat shock, that is, sudden heat fluctuation. Therefore, it is desirable to cover the inner surface of the stave with refractory bricks when constructing the blast furnace. Even when such a refractory brick is provided, there has been a demand for a blast furnace capable of stably maintaining an appropriate in-furnace surface profile over a long period of time without causing a rapid change in the in-furnace surface profile at the beginning of operation after firing.

  An object of the present invention is to provide a blast furnace morning glory structure capable of forming an in-furnace surface profile in a stable operation period after a refractory brick disappears due to thermal shock or wear, and a design method thereof.

  The present invention realizes a blast furnace in which the change in the surface shape of the furnace is small over one blast furnace cost, and stable operation and long life can be achieved for a long time. That is, in the present invention, the thickness of the refractory bricks arranged on the in-furnace surface side of the stave when the blast furnace is constructed is reduced, and the stave outside the refractory bricks is arranged at an appropriate position. Because of these, after the refractory brick disappears in the initial stage of blast furnace operation after firing, an adhering layer is quickly generated on the surface of the stave, due to wear of the refractory brick in the furnace when shifting from the initial stage of blast furnace operation to the stable operation period. Since the change in the furnace surface profile becomes small, stable operation of the blast furnace can be maintained for a long time.

The present invention employs the following means in order to solve the above problems and achieve the object.
That is,
(1) A blast furnace morning glory structure according to an aspect of the present invention is a cylindrical morning glory structure that is provided between a tuyere portion and a furnace belly portion of a blast furnace, and expands in the vertical direction. The morning glory portion has an annular iron skin, a copper or copper alloy morning glory stave provided on the inner periphery of the iron skin, and a refractory brick provided on the inner periphery of the morning glory stave. The horizontal thickness of the refractory brick at the upper edge position of the morning glory part is 50 to 250 mm; the horizontal thickness of the refractory brick at the lower edge position of the morning glory part is 200 to 500 mm; The narrow angle formed between the surface of the morning glory stave and the horizontal plane is 75 to 82 ° when viewed in a cross section including it.

According to the blast furnace morning glory structure described in the above (1), the thickness of the refractory bricks in the blast furnace morning glory is made thinner than the thickness of the refractory bricks disposed in the conventional blast furnace, so It is possible to greatly suppress changes in the furnace surface profile caused by wear and disappearance of the refractory bricks in the morning glory. Furthermore, the brick cost at the time of blast furnace construction can be reduced, and the brick construction period of morning glory can be shortened.
That is, in the said aspect of this invention, the furnace surface profile of the morning glory part of the blast furnace at the time of burning is defined by the surface of the refractory brick arrange | positioned at the furnace inner surface side of a stave. In the initial stage of blast furnace operation after firing, most of the refractory bricks disappear due to thermal shock and wear. However, after most of the refractory bricks disappear, the deposit layer that is generated and grown on the surface of the stave forms an in-furnace surface profile that is close to that of the fire (design time), and may shift to the stable operation period of the blast furnace. it can. In particular, the inner surface of the furnace in the morning glory of the blast furnace is a fusion zone of the charge descending in the furnace (softening and melting of the ore in the charge starts, and the ores in the semi-molten state are fused together. The region that is in contact with the root of the region connected in a shape. After the disappearance of the refractory brick, the charge containing the ore in a semi-molten state is cooled and fixed on the surface of the stave main body, and thereby an adhesion layer generated on the inner surface of the stave main body is generated and grows.

In the said aspect of this invention, the morning glory part stave arrange | positioned in the morning glory part of a blast furnace is comprised by the stave main body made from copper or a copper alloy.
Here, since the thermal conductivity and heat removal capability of copper and copper alloys are high, the charge containing semi-molten ore can be rapidly cooled on the surface of the stave body by using a stave body made of copper or copper alloy. can do. Thereby, the deposit layer can be quickly generated and grown on the surface side in the blast furnace of the stave after the disappearance of the refractory brick. Furthermore, even if the deposit layer disappears due to changes in the charge and operating conditions of the blast furnace, the deposit layer can be regenerated early.

In the said aspect of this invention, the horizontal thickness of the refractory brick in the upper edge position of a morning glory part is 50-250 mm; The horizontal thickness of the refractory brick in the lower edge position of a morning glory part is 200-500 mm. That is, in this structure, the thickness of the refractory brick in the morning glory portion of the blast furnace is thinner than in the past. As a result, it is possible to reduce the change in the furnace surface profile of the morning glory part of the blast furnace before the disappearance of the refractory brick in the furnace height direction and the circumferential direction of the furnace, and the in-furnace surface profile of the morning glory part of the blast furnace after the disappearance of the refractory brick. it can.
In particular, in a large blast furnace with a blast furnace capacity of 4000 m ³ or more, the wear state of the refractory bricks in the furnace circumferential direction may vary greatly between the initial operation period after the firing and the stable operation period. Conventionally, this has caused a problem that the circumferential balance of the furnace surface profile has deteriorated, leading to unstable blast furnace operation and reduced productivity.
According to the above aspect of the present invention, such a problem of the large blast furnace can be solved, and the profile change of the furnace inner surface from the initial operation period after the blast furnace can be fired to the stable operation period can be minimized. This eliminates the need to adjust the operating conditions and the charge distribution over and over according to changes in the furnace surface profile at the initial stage of operation after blast furnace firing. Alternatively, the adjustment frequency of the operating conditions and the charge distribution is remarkably reduced as compared with the conventional case, and the blast furnace operation can be stabilized at a high level for a long time.
Furthermore, according to the above aspect of the present invention, since the amount of refractory bricks in the morning glory portion of the blast furnace can be reduced as compared with the conventional case, it is possible to reduce the brick purchase cost and the brick work cost at the time of blast furnace repair, and further, the blast furnace repair The construction period can be shortened.

As described above, the in-furnace surface profile in the stable operation period of the blast furnace is formed by a deposit layer generated on the stave furnace inner surface after the disappearance of the refractory bricks. According to the results of the investigations by the present inventors, the charge containing the semi-molten ore in the morning glory portion is rapidly cooled on the surface of the stave body during the stable operation period of the blast furnace, so that It has been found that the tilt angle of the kimono layer with respect to the horizontal plane in the furnace surface profile is about 75 °.
In the above aspect of the present invention, when the morning glory portion is viewed in a cross section including its axis, the narrow angle formed by the surface of the morning glory stave and the horizontal plane is 75 to 82 °, more preferably 75 to 78 °. Arrange the morning glory stave of the blast furnace.
With this configuration, in the initial stage of operation after the blast furnace is fired, the inclination angle of the deposit layer that naturally occurs on the surface of the stave furnace after the refractory brick disappears becomes close to the inclination angle (about 75 °) in the above blast furnace operation stable period. Can be. Thereby, since the rapid change of the in-furnace surface profile which arises from the operation | movement initial stage after the blast furnace firing to the operation | movement stable period can be suppressed, operation instability and productivity fall can be avoided.

(2) In the blast furnace morning glory structure described in (1) above, the vertical dimension from the center of the tuyere provided at the tuyere to the lower edge position of the morning glory is 1200 to 1350 mm; It is desirable that the horizontal dimension from the tip of the head to the lower edge position of the morning glory part is 700 to 1100 mm.
Compared to the conventional blast furnace morning glory structure, this is a morning glory stave consisting of a copper or copper alloy stave body with high thermal conductivity and high heat extraction (cooling) capacity, and the lower end in the blast furnace has a high temperature region. Place it at a position that is close to the raceway at the tip of the tuyere. Thereby, it is possible to maintain a more stable in-furnace profile in blast furnace operation by generating a stable deposit layer on the surface inside the blast furnace of the morning glory portion stave that is thin and difficult to peel off. This protective effect of the deposit layer makes it possible to slow the damage rate of the stave and prolong the life of the morning glory portion of the blast furnace. The above-described raceway is a space having a high porosity in which high-speed gas is blown from the tuyere and fluidized coke in front of the tuyere.
According to the above aspect of the present invention, from the initial operation period after the blast furnace is fired to the stable operation period, a stable deposit layer is formed on the inner surface of the morning glory stave that is thin and difficult to peel off. Thus, even when the charging and operating conditions of the blast furnace are changed, changes in the furnace surface profile in the morning glory portion in the furnace height direction and the furnace circumferential direction are reduced. Instable operation and lowering of productivity due to deterioration of the circumferential balance of the furnace surface profile, which is a problem particularly in large blast furnaces, can be avoided, and long-term operation stabilization of the blast furnace can be achieved.

(3) In the blast furnace morning glory structure described in (1) above, the vertical dimension from the center of the tuyere provided at the tuyere to the upper edge position of the morning glory is preferably 4500 mm to 5500 mm.
Here, the furnace inner surface of the morning glory part of the blast furnace supports the root of the fusion zone of the charge descending in the furnace and plays a role of maintaining stable operation of the blast furnace.
Therefore, by setting the height of the upper edge position of the morning glory stave within the above range, even if the height position of the root portion of the charge cohesive zone fluctuates due to a change in the operating condition of the blast furnace, The morning glory stave is placed above the mouth at an appropriate angle of inclination (the narrow angle formed by the surface of the morning glory stave described above and the horizontal plane), and the vertical direction from the center of the tuyere to the upper edge position of the morning glory By making the dimension of the sufficient length, the root portion of the cohesive zone can be stably supported.

In the blast furnace morning glory structure according to the above aspect of the present invention, it is desirable that the morning glory stave has a projection that protrudes from the reference surface to the inside of the furnace with the surface inside the furnace as a reference surface and is continuous in the furnace circumferential direction. .
In this configuration, the protrusion (including the semi-molten iron ore) descends around the root part of the cohesive zone that descends in the blast furnace due to the protrusion that protrudes from the reference surface, which is the surface inside the furnace, to the inside of the furnace. Decrease speed. Thereby, even if the deposit layer on the reference surface is peeled off due to a change in the operating state of the blast furnace, the deposit layer can be generated and grown at an early stage along the reference surface. That is, since an appropriate in-furnace surface profile can be formed by the generation and growth of the deposit layer, the operation in the blast furnace can be stably maintained for a long time.
In addition, by covering the stave body with a deposit layer that has been generated and grown along the reference surface of the stave body (cell flying effect), the stave body is not directly exposed to the high-temperature cohesive zone, and the morning glory part and the furnace belly part Heat resistance as a stave can be increased.

In particular, in the above aspect of the present invention, a copper or copper alloy stave body having a high thermal conductivity and a high heat extraction capability is used, so the charge containing the semi-molten ore descending in the blast furnace is the reference plane. After decelerating by the protrusion, it cools rapidly and adheres to the reference surface. As a result, even if the deposit layer on the reference surface is peeled off due to a change in the operating condition of the blast furnace, the deposit layer of the deposit can be regenerated at an early stage.
In addition, by the protrusions continuously provided in the entire circumference of the furnace circumferential direction with respect to the morning glory stave, it becomes easy to maintain a good circumferential balance of the furnace surface profile in the operation of a large blast furnace, Long-term high-level stable operation of the blast furnace becomes possible.

In the morning glory portion stave, it is desirable to form a cooling conduit on the protrusion in addition to the cooling conduit formed inside the stave body.
In the above aspect of the present invention, since the material of the stave body is made of copper or a copper alloy having a high thermal conductivity and a high heat removal capability, the protrusion is sufficiently cooled only by the cooling conduit inside the stave body. By forming a cooling conduit inside the protrusion and directly cooling the protrusion, the surface temperature can be lowered to further promote the generation of deposits.

(4) A blast furnace design method according to an aspect of the present invention includes a tuyere part, a furnace belly part, and a cylindrical morning glory part that is provided between the tuyere part and the furnace belly part and expands in the vertical direction. And the morning glory portion is an annular iron skin, a copper or copper alloy morning glory stave provided on the inner periphery of the iron skin, and a refractory brick provided on the inner periphery of the morning glory stave. The horizontal thickness of the refractory brick at the upper edge position of the morning glory part is 50 to 250 mm; and the horizontal thickness of the refractory brick at the lower edge position of the morning glory part The narrow angle formed by the surface of the morning glory portion stave and the horizontal plane is 75 to 82 ° when the morning glory portion is viewed in a cross section including its axis.
According to this blast furnace design method, the same effect as the blast furnace morning glory structure according to one aspect of the present invention described above can be obtained.

It is a mimetic diagram showing a blast furnace concerning one embodiment of the present invention. It is sectional drawing which shows the installation state of the morning glory part stave and the firebrick at the time of the burning (design time) of the blast furnace morning glory structure of the same blast furnace, and an initial furnace surface profile. It is sectional drawing which shows the surface profile in a furnace at the time of the burning (design time) of the blast furnace morning glory structure of the same blast furnace, the operation initial stage, and the operation stable period. It is a graph which shows the change of the years of operation and production in the conventional blast furnace morning glory structure. It is a schematic diagram which shows the state of the refractory brick for morning glory parts at the time of the burning (design time) of the conventional blast furnace morning glory structure. It is a schematic diagram which shows the state in which the refractory brick for morning glory parts in the operation | working initial stage of the conventional blast furnace morning glory structure is being worn out. It is a schematic diagram which shows the state which the refractory brick for morning glory parts in the operation stable period of the conventional blast furnace morning glory structure disappeared. It is a graph which shows the change of the operation years and production amount in the blast furnace morning glory structure of embodiment. It is a schematic diagram which shows the operation initial state of the morning glory part refractory brick at the time of burning (design time) of the blast furnace morning glory structure. It is a schematic diagram which shows the state in which the refractory brick for morning glory parts in the operation | movement initial stage of the same blast furnace morning glory part is being worn out. It is a schematic diagram which shows the state which the refractory brick for morning glory parts in the operation stable period of the same blast furnace morning glory structure disappeared.

Hereinafter, an embodiment of a blast furnace morning glory structure and a design method thereof according to the present invention will be described with reference to the drawings.
In FIG. 1, a blast furnace 1 has a cylindrical furnace body 2 constructed on a foundation ground.
The furnace body 2 is divided into a furnace mouth part S1, a shaft part S2, a furnace belly part S3, a morning glory part S4, a tuyere part S5, and a furnace bottom part S6 in order from the upper gas collecting mantel 3. Generally, the inner diameter of the shaft portion S2 expands downward, the inner diameter of the furnace belly portion S3 is the maximum diameter, and the inner diameter of the morning glory portion S4 decreases downward. The morning glory part S4 has a cylindrical shape, is provided between the tuyere part S5 and the furnace belly part S6, and expands in diameter in the vertical direction.

In the furnace body 2, a charging device is usually installed in the gas collection mantel 3, and a granular charge 4 is charged into the furnace from this charging device. As the charge 4, an ore-based charge having a particle size of about 8 to 25 mm and a coke-based charge having a particle size of about 20 to 55 mm are alternately charged in layers. As a result, a massive band 4A in which iron ore and coke are alternately layered is formed in the furnace port portion S1 and the shaft portion S2 in the furnace.
The furnace body 2 is provided with a tuyere 5 above the furnace bottom S6, and hot air 5A is blown from here. The hot air 5A burns the coke in the block 4A to a higher temperature, and in the vicinity of the tuyere 5 raceway 5B (high-speed gas is blown from the tuyere 5 to cause the coke in front of the tuyere 5 to flow. A space having a high porosity is formed. Due to the high heat of the raceway 5B, the iron ore in the block 4A is melted.

The coke combustion and the melting of the iron ore proceed sequentially in the lower part of the block 4A, and a substantially conical fusion band 4B is formed in the furnace from the morning glory part S4 to the lower part of the shaft part S2.
The iron 6A melted in the fusion zone 4B passes through the dripping zone 4C, drops toward the furnace bottom S6, and accumulates in the furnace bottom S6 as a molten iron 6B. Coke or the like that could not be burned in the cohesive zone 4B passes through the dripping zone 4C and descends, accumulates in the furnace bottom S6, and forms a conical furnace core 4D on the hot metal 6B.
In the furnace body 2, a hot iron outlet 6 is installed in the furnace bottom portion S <b> 6, and the hot metal 6 </ b> B accumulated in the furnace bottom portion S <b> 6 is taken out of the blast furnace 1 through the hot iron outlet 6.

The furnace body 2 has an iron skin 2A on the outermost periphery, and a cooling stave and a refractory brick 2D are stretched inside the iron skin 2A.
A stave 2B for the shaft is stretched in a region S7 facing from the upper portion of the shaft portion S2 to the middle lump 4A. In this region S7, since the granular charge 4 contained in the massive band 4A descends sequentially while contacting the surface of the stave 2B, mechanical wear may occur on the surface of the stave 2B.
A morning glory stave 2C is stretched from a lower portion of the shaft portion S2 to a region S8 including the furnace belly S3 and the morning glory S4. In this region S8, a fusion zone 4B made of a high-temperature charge 4 (a region in which softening and melting of the ore in the charge 4 has started, and the ores in a semi-molten state are fused together and connected in a plate shape. ), The root part 4E descends sequentially while coming into contact, so that the surface of the stave 2C inside the blast furnace 1 may be worn due to high temperature.
A refractory brick 2D is stretched on the inner surfaces of the staves 2B and 2C as necessary. In addition, the refractory bricks 2E are thickly stacked on the furnace bottom S6 where the hot metal 6B is stored.

In this embodiment, as shown in FIG. 2, the blast furnace morning glory structure 9 is employed in a region from the lower part of the furnace belly S3 to the tuyere 5 of the tuyere part S5, which mainly includes the morning glory part S4.
The morning glory portion S4 of the blast furnace morning glory structure 9 includes an annular iron skin 2A installed on the outside, a copper or copper alloy morning glory stave 10 provided on the inner periphery of the iron skin 2A, and this morning glory portion. The fire brick 20 (2D) provided on the inner periphery of the stave 10 is provided. The morning glory portion stave 10 may be a casting that is cast together with copper or a copper alloy. The stave 2C includes a thin plate-like stave body 11 cut out from a copper or copper alloy plate.
A plurality of horizontally extending projections 12 are formed on the surface side of the stave body 11, and a recess 13B that is recessed toward the outside of the blast furnace 1 is formed therebetween. The surface of the recess 13 </ b> B that is one step lower than the protrusion 12 is a flat surface (reference surface) 13.

The morning glory portion stave 10A (10) disposed on the upper end side of the morning glory portion S4 is disposed from the morning glory portion S4 to the furnace belly portion S3. In the morning glory portion stave 10A, only the portion located in the morning glory portion S4 is inclined with respect to the axis O of the morning glory portion S4. Specifically, when the morning glory portion S4 is viewed in a cross section including the axis O, the inclination angle (narrow angle) α between the plane (reference plane) 13 of the morning glory portion stave 10 and the horizontal plane is 75 to 82 °. Among them, the angle is preferably 75 to 78 °. In addition, the morning glory portion stave 10 arranged on the tuyere portion S5 side of the morning glory portion stave 10A is similarly inclined with respect to the axis O.
Horizontal thickness _{L U} of refractory bricks 20 (2D) at the upper edge position _{E U} morning glory portion S4, a 50 to 250 mM, preferably about 50 to 100 mm. Moreover, the horizontal thickness L _L of the refractory brick 20 (2D) at the lower edge position E _L of the morning glory part S4 is 200 to 500 mm, preferably about 200 to 300 mm.

The concave portion 13B including the flat surface 13 serving as a reference surface is formed by cutting from the surface of the stave body 11, and the protrusion 12 is formed by being left uncut during the cutting. Here, the flat surface 13 is a reference surface of the morning glory portion stave 10, and the protrusion 12 protrudes from the reference surface of the morning glory portion stave 10.
The protrusions 12 are continuous with each other when the morning glory stave 10 is stretched in the furnace, and in the blast furnace 1, each protrusion 12 forms a complete annular shape.
The tip surface of the protrusion 12 may be coated with a high hardness material such as TiN, TiC, WC, or Ti—Al—N.
The protruding amount of the protruding portion 12 from the flat surface 13 that is the reference surface is 50 to 150 mm (the protruding amount that is approximately 1 to 3 times the maximum particle size 55 mm of the coke-based charge having a large average particle size), and the adjacent protruding portion The interval of 12 is about 500 to 1000 mm, and more preferably 500 to 700 mm.

In particular, the adjacent protrusions 12 increase the cooling efficiency of the charge by reducing the rate of descent of the charge on the flat surface 13 which is the reference surface of the stave body 11, and promote the formation of the deposit layer. The interval between the adjacent protrusions 12 is important.
When the interval between the adjacent protrusions 12 becomes larger than 1000 mm, the descending speed of the charge containing the semi-molten ore that descends particularly near the protrusions 12 on the high position side is reduced, and the flat surface 13 that is the reference surface is cooled by cooling. This reduces the effect of forming the deposit layer.
When the interval between the adjacent protrusions 12 becomes narrower than 500 mm, the descending speed of the charge containing the semi-molten ore descending between the adjacent protrusions 12 is reduced, and is generated on the plane 13 which is the reference surface by cooling. The thickness of the deposit layer becomes excessively thick. If the deposit layer is formed too thick, when the deposit layer is peeled off due to changes in the operating conditions of the blast furnace 1, the furnace inner surface profile of the morning glory part and the furnace belly part will change greatly, and the stable operation of the blast furnace 1 will be improved. It is not preferable to maintain.

As shown in FIG. 2, a refractory 13 </ b> A is stretched in the recess 13 </ b> B (between adjacent protrusions 12) along the plane 13 that is a reference plane. A refractory brick 20 different from the refractory 13 </ b> A is stretched along the refractory 13 </ b> A and the front end surfaces of the protrusions 12.
In the blast furnace morning glory structure 9 of the present embodiment, the refractory brick 20 constitutes the refractory brick 2D inside the stave 2C described above (see FIG. 1).
As described above, as shown in FIG. 2, the thickness of the refractory bricks 2D, the horizontal direction of the thickness _{L U} of refractory bricks 20 that is at the upper edge position _{E U} morning glory portion for the staves 10 is 50 to 250 mM, the lower edge thereof horizontal thickness _{L L} refractory brick 20 at the position _{E L} is 200 to 500 mm.

The refractory brick 20 and the refractory 13 </ b> A protect the morning glory portion stave 10 from heat shock when the blast furnace 1 is fired (a state in which a coating with deposits is not yet obtained).
At the initial stage of operation after the blast furnace 1 is fired, the refractory brick 20 and the refractory 13A are sequentially worn by the high heat and frictional force received from the root 4E of the fusion zone 4B of the charge 4 in the high temperature state shown in FIG. . At this time, as shown in FIG. 3, the in-furnace profile P <b> 1 in the morning glory portion S <b> 4 is constituted by the worn surface of the refractory brick 20.

However, in the furnace, due to the operation of the blast furnace 1, the deposit 7 layer caused by the charge 4 grows against disappearance due to the wear of the refractory brick 20, and the inside surface of the morning glory portion stave 10 has the deposit 7 layer. (Furnace profile P2).
After most of the refractory bricks 20 disappeared from the blast furnace 1 in the initial stage of operation, after 4 years from the igniting, deposits 4 are attached to the reference surface 13 of the stave body 11 or the surface of the refractory 13A. Seven layers are generated and grown, and the deposit 7 is formed with a small thickness. And the refractory 13A and the projection part 12 in the morning glory part S4 are further coat | covered with the deposit 7 layers (furnace profile P3).
Furthermore, after 4 to 10 years have passed since the burning, the deposit 7 layer further grows on the reference surface 13 of the stave body 11 or the deposit 7 layer formed by the in-furnace profile P3, and the deposit 7 By increasing the thickness of the layer, the furnace surface profile P0 of the refractory brick 20 in the morning glory portion S4 at the time of firing is approached. Further, even if the deposit 7 layer and the refractory 13A on the flat surface 13 which is the reference surface are peeled off due to a change in the operating state of the blast furnace 1, and the flat surface 13A is exposed, the plane 7 13 or the projection 12 is covered. Thereby, the inner surface of the blast furnace 1 of the morning glory portion stave 10 is automatically leveled to a smooth surface by the seven layers of deposits.

Returning to FIG. 2, a cooling pipe (not shown) is formed inside the stave body 11, and a cooling pipe 16 is connected to the back side of the stave body 11.
Cooling water from the cooling pipe 16 is passed through the cooling pipe line inside the stave body 11, and the flat surface 13 and the protrusion 12 that are the reference plane of the morning glory portion stave 10 are cooled by adjusting the flow rate of the cooling water. , Each is adjusted to an appropriate temperature.
By such appropriate cooling, the growth of the deposit 7 layer (see FIG. 3) of the charge 4 is promoted, and the thickness of the deposit 7 layer on the surface of the morning glory stave 10 inside the blast furnace 1 is appropriately adjusted. The covering state can be adjusted.

As described above, in the blast furnace morning glory structure 9 of the present embodiment, the initial surface shape (initial profile) is formed on the inner surface of the blast furnace 1 of the refractory brick 20 from the start of the blast furnace (during design) to the initial stage of the blast furnace operation. After 20 disappears due to wear, an in-furnace surface profile in the stable operation period is formed on the inner surface of the blast furnace 1 by the seven deposits generated on the surface of the stave body 11.
In the conventional blast furnace morning glory structure, the in-furnace surface profile in the morning glory greatly changes in the early stage of operation from the start of the fire to 2 to 4 years later, which causes instability of the blast furnace operation and a decrease in productivity. It was.
According to the present embodiment, the morning glory portion stave is formed such that the thickness of the fireproof brick 20 in the morning glory portion S4 is reduced and the deposit 7 layer is quickly formed on the reference surface of the stave body 11 after the fireproof brick 20 disappears. 10 is inclined at an appropriate angle, so that the change in the furnace surface profile at the initial stage of operation after firing is small compared to the furnace surface profile at the time of firing (design time), thus improving the stability and productivity of blast furnace operation. It can be maintained well.

In the blast furnace morning glory structure 9 of this embodiment, the arrangement of the morning glory stave 10 with respect to the tuyere 5 is set to a specific setting.
That is, in the blast furnace morning glory structure 9, the morning glory portion stave 10 arranged in the region of the morning glory portion S4 has a horizontal plane and the reference plane 13 of the morning glory portion stave 10 when the morning glory portion S4 is viewed in a cross section including the axis. Is set to be 75 to 82 °, more preferably 75 to 78 °.

The lower edge position of the morning glory part S4 from the center H0 of the tuyere 5 provided in the tuyere part S5 (the lower end position of the inner surface of the blast furnace 1 of the morning glory stave 10 installed at the lowest stage of the blast furnace morning glory structure 9) The vertical dimension H1 to E _L is 1200 to 1350 mm, and the horizontal dimension D1 from the tip D0 of the tuyere 5 to the lower edge position E _L of the morning glory part S4 is 700 to 1100 mm (see FIG. 2). ). The center height H0 of the tuyere 5 refers to the height of the pivot center position when the nozzle of the tuyere 5 is pivotable.
According to this embodiment, compared with the conventional blast furnace morning glory structure, the morning glory portion stave 10 made of the copper or copper alloy stave body 11 having high thermal conductivity and high heat extraction capability is provided in the blast furnace 1. Placed at a position where the lower edge position _EL is close to the tuyere raceway 5B (a high porosity space in which high-speed gas is blown from the tuyere and fluidized coke in the tuyere is fluidized) in the high temperature region. Has been. As a result, a stable deposit layer that is thin and difficult to peel off can be formed on the surface of the morning glory portion stave 10 in the blast furnace 1 at an early stage, and a more stable in-furnace profile can be maintained in blast furnace operation. . Furthermore, since the wear rate of the stave can be slowed by the protective effect, the life of the blast furnace morning glory structure can be extended.
From the initial operation after the blast furnace 1 is fired to the stable operation period, a stable deposit layer that is thin and difficult to peel off is formed on the inside surface of the morning glory stave 10 so that the blast furnace 1 is charged and operated. Also, the change in the furnace surface profile of the morning glory S4 in the furnace height direction and the furnace circumferential direction becomes smaller than the furnace surface profile in the firing (design time). As a result, it is possible to avoid operational instability and productivity reduction due to deterioration of the circumferential balance of the in-furnace surface profile, which is a problem particularly in a large blast furnace, and to stabilize the long-term operation of the blast furnace 1.

Further, the upper edge position of the morning glory portion S4 from the tuyere center H0 provided at the tuyere portion S5 (the upper end of the surface in the blast furnace 1 of the morning glory portion stave 10 installed at the lowermost stage of the blast furnace morning glory structure 9 described above) position) dimension H2 of the vertical direction to the _{E U} is a 4500～5500Mm.
The inner surface of the morning glory portion S4 of the blast furnace 1 supports the root 4E of the fusion zone 4B of the charge 4 descending in the blast furnace 1, and plays a role of maintaining stable operation of the blast furnace 1. Thus, the upper edge position E the height of the _U of the bosh section for the staves 10 in the above range, the height position of the root portion 4E of the cohesive zone 4B of charge 4 by a change in the operational state of the blast furnace 1 Even when fluctuates, the root portion 4E of the cohesive zone 4B is stabilized by arranging the morning glory portion stave 10 at an appropriate morning glory angle (inclination angle) above the tuyere 5 and sufficiently increasing the dimension H2. Can be supported.

In the present embodiment described above, the refractory bricks 20 are worn with the operation after the blast furnace is fired. However, due to the generation of the seven deposits on the inner surface of the morning glory stave 10, The in-furnace surface profile of the direction is maintained in an appropriate state, and the deterioration of the operation performance of the blast furnace 1 due to the aging of the in-furnace surface profile can be minimized.
Below, the secular change of the in-furnace surface profile in the blast furnace morning glory structure 9 of this embodiment and the secular change in the conventional blast furnace morning glory structure to which this embodiment is not applied are compared by computer simulation.

FIG. 4 shows a change in the production amount with the passage of operating years in the conventional blast furnace morning glory structure to which the present embodiment is not applied. 5, 6, and 7 schematically show the wear situation of the morning glory refractory brick 20 at the time of firing (designing), the initial operation and the stable operation period of the blast furnace morning glory structure.
FIG. 8 shows a change in the production amount with the passage of operating years in the blast furnace morning glory structure 9 to which the present embodiment is applied. 9, 10, and 11 schematically show the wear state of the refractory brick 20 of the morning glory portion S <b> 4 at the time of firing (design time), the initial operation and the stable operation period of the blast furnace morning glory structure 9. .

The conventional blast furnace 1 whose production amount is changed in FIG. 4 has the same basic structure of the morning glory portion S4 as the embodiment of the present invention shown in FIG. 1 and FIG. the thickness of the furnace refractory bricks 20 disposed on the surface side (the horizontal direction of the thickness at the lower edge position _{E L} of the bosh section for staves 10) is larger than 500mm in use staves 10, the upper edge position _{E u} is greater than 250mm The dimension H2 is smaller than 4000 mm, and the inclination angle α is larger than 82 °.

In FIG. 4, 6 months from the time of blast furnace 1 firing (operating years 0 years) is the “fired start-up period T1”. During this period, the operation adjustment such as charging of the blast furnace 1 and operation conditions is performed, and the production amount is raised to the target production level L0.
The operation period from 6 months to the second year is the “initial T2 after start-up”. During this period, in the morning glory portion S4, the refractory brick 20 stretched inside the morning glory portion stave 10 is maintained with very little damage, and the surface of the refractory brick 20 and the initial balance profile and circumferential balance are maintained. Is maintained well (see FIG. 5). For this reason, the stable operation is continued while maintaining the actual production amount at the target production level L0 (see time T2 in FIG. 4).

The period of operation from 2 to 4 years is “morning glory brick damage dropout time T3”. At this time, in the morning glory portion S4, the refractory bricks 20 are almost damaged, and each portion is sequentially dropped, so that the furnace surface profile is deteriorated and the circumferential balance of the morning glory portion S4 is deteriorated (see FIG. 6). In particular, damage or dropout of the refractory brick 20 starts from a specific part of the morning glory S4 in the furnace circumferential direction and sequentially expands to the entire circumference. For this reason, the furnace surface profile deteriorated, and the blast furnace operation was greatly affected by the imbalance in the circumferential balance, becoming unstable until reaching the entire circumference, and the state of greatly reduced production continued ( (See time T3 in FIG. 4).
During this period, various blast furnace operation adjustments are made, so that a deposit layer is formed on the inner surface of the blast furnace in the morning glory S4, the furnace surface profile in the furnace circumferential direction is smoothed, and the circumferential balance is restored. Stabilize and recover production.

The operation period of 4 to 10 years is the “operation stable period T4”. At this time, in the morning glory portion S4, the refractory bricks 20 are completely disappeared, and the inner surface of the furnace is formed by the surface of the morning glory portion stave 10 or the deposit layer (see FIG. 7). At the time when the blast furnace operating conditions and the charge distribution are optimized, seven layers of deposits of appropriate thickness are generated on the surface of the morning glory stave 10. Due to the seven layers of deposits, a smooth in-furnace surface profile is formed on the in-furnace surface, and the circumferential balance over the entire circumference in the furnace circumferential direction is improved. For this reason, compared with morning glory brick damage drop-off time T3, blast furnace operation is also stabilized and production volume is also recovered. The production volume L1 at this time has a linear trend that gradually decreases to the right due to aging of each part of the blast furnace (see time T4 in FIG. 4).
However, in the conventional blast furnace morning glory structure, seven layers of deposits on the inner surface of the morning glory staves 10 are sporadic when the quality of raw materials and fuels and the operating conditions change during the mid-term operation stable period T4. May peel off or fall off. Along with such a drop, there is a problem that the furnace surface profile temporarily changes suddenly, the circumferential balance deteriorates, and a large fluctuation of the production amount occurs temporarily.

  The operation period of 10 to 14 years is “operation unstable period T5”. At this time, in the morning glory portion S4, wear of the morning glory portion stave 10 also progresses, and the influence due to fluctuations in raw fuel quality (deterioration of coke quality, fluctuation in sintering quality, etc.) becomes large. The disappearance of deposits and the change in regeneration increase. Along with this, the change in the furnace surface profile and the change in the circumferential balance further increase, and the situation in the blast furnace 1 fluctuates greatly as compared with the operation stable time T4 described above. Thereby, since the aging deterioration of each part of the blast furnace 1 further proceeds, as a result, the production amount decreases and the fluctuation also increases. The production amount L2 at this time has a linear trend that is largely downward to the right (see time T5 in FIG. 4).

  Over 14 years of operation, full production at the upper limit of the capacity of the blast furnace 1 becomes difficult due to damage to the stave of the high heat load part of the morning glory part S4 or the shaft part S2 and the progress of wear of the hearth wall bricks. Sudden wind breaks and long wind breaks for repairs are required. As a result, the operating conditions are frequently changed, and the deposit 7 on the morning glory portion S4 cannot be stably maintained due to the fluctuation of the tuyere conditions. In such a situation, as a result, the production volume is greatly reduced, and the operating conditions are becoming more and more unstable due to the aging and aging of various facilities. Both of the stability have reached the worst period and the end of the furnace is reached.

The blast furnace 1 shown in FIG. 8 adopts the blast furnace morning glory structure 9 of the present embodiment shown in FIG. 1, FIG. 2 and FIG. 3 described above, on the inner surface side of the morning glory portion stave 10. horizontal thickness of the refractory bricks 20 spanned is, the upper edge position _{E u} morning glory for stave 10 positioned at the bottom is 50 to 250 mM, the lower edge position _{E L} morning glory for staves 10 in 200~500mm There is an inclination angle α between the plane 13 as a reference plane and a horizontal plane of 75 to 82 °.

In FIG. 8, 6 months from the time when the blast furnace 1 is fired (operating years 0 years) is the “fired start-up period U1”. During this period, operation adjustments such as charging of the blast furnace and operating conditions are performed, and the production amount is raised to the target production level L0. At this time, it is in-furnace profile P0 (refer FIG. 3).
The operation period from 6 months to the second year is the “initial U2 after startup”. During this period, in the morning glory portion S4, the refractory brick 20 stretched inside the morning glory portion stave 10 is maintained with very little damage, and the surface of the refractory brick 20 and the initial balance profile and circumferential balance are maintained. Is maintained well (see FIG. 9). For this reason, the stable operation is continued while maintaining the actual production amount at the target production level L0 (see time U2 in FIG. 8, profile P0 in FIG. 3).

  The operation period of 2 to 4 years is the “morning glory brick dropout time U3”. At this time, in the morning glory part S4, the refractory brick 20 may be damaged, and the parts may fall off sequentially. However, since the thickness of the refractory brick 20 is thinly formed based on this embodiment, the occurrence of a large change in the furnace surface profile or a large change in the circumferential balance of the morning glory portion S4 is suppressed as compared with the conventional case. (See FIG. 10). Thereby, it is possible to avoid the unstable operation and the large decrease in the production amount as in the conventional case (time T3 in FIG. 4) (see time U3 in FIG. 8, profile P1 in FIG. 3).

  The operation period of 4 to 10 years is the “operation stable period U4”. At this time, in the morning glory portion S4, the refractory bricks 20 are completely disappeared, and the inner surface of the furnace is formed by seven layers of deposits generated on the surface of the morning glory portion stave 10 (see FIG. 11). At this time, in the blast furnace morning glory structure 9 of the present invention, the morning glory portion stave 10 is arranged so that the plane 13 which is the reference surface of the morning glory portion stave 10 has an appropriate inclination angle α (75 to 82 °). Yes. As a result, the deposit 7 layer is efficiently generated with a thin thickness in the furnace surface of the morning glory stave 10 and a uniform thickness in the furnace circumferential direction, so that a smooth furnace surface profile is secured, and the blast furnace The circumferential balance over the entire circumference of 1 is also good. For this reason, blast furnace operation is also stable, and a value close to the target production level L0 can be secured (see time U4 in FIG. 8, profiles P2 to P3 in FIG. 3).

  In addition, since the deposit 7 layer is formed and grows on the inside surface of the morning glory stave 10 in a state where the thickness is thinner and it is difficult to peel off, the deposit layer is sporadic as in the past. By dropping off, the furnace surface profile does not change suddenly. Furthermore, the circumferential balance over the entire circumference of the blast furnace 1 does not deteriorate, and stable blast furnace operation can be maintained. In addition, if the inclination angle of the flat surface 13 that is the reference surface of the morning glory portion stave 10 is appropriate, even if the deposit 7 layer sporadically peels off and drops when the operating conditions change, The seven layers of deposits are efficiently regenerated on the reference surface, and there is no significant decrease in production volume as in the past (time T4 in FIG. 4).

  The operation period of 10 to 14 years is “operation unstable period U5”. At this time, the morning glory S4 reaches the end of the furnace as in the conventional case (time T5 in FIG. 4). However, in the meantime, due to the appropriate inclination angle α (75 to 82 °) of the plane 13 that is the reference surface of the morning glory stave 10 described above, the furnace surface profile is optimized and the circumferential balance is optimized, A value close to the target production level L0 can be secured (see time U5 in FIG. 8).

In addition, this invention is not limited only to embodiment mentioned above, The deformation | transformation etc. in the range which can achieve the objective of this invention are included.
In the above-described embodiment, the furnace surface profile in the stable operation period formed by the inside surface of the morning glory stave 10 and the deposit 7 thereof has an inclination angle of 75 to 78 ° with respect to the horizontal plane of the morning glory stave 10. As described above, the same effect can be obtained even when the inclination angle α is 75 to 82 °.

In the above-described embodiment, the lower edge position E _L (see FIG. 2) of the inner surface of the morning glory portion stave 10 installed at the lowest stage of the blast furnace morning glory structure 9 is the morning glory portion S4 from the center H0 of the tuyere 5. any of a vertical dimension H1 is 1200~1350mm until lower edge position _{E L,} and the horizontal dimension D1 from the tip D0 of tuyeres 5 to the lower edge position _{E L} of the bosh section S4 is in 700~1100mm That's fine. For example, the boundary of the bosh section S4 and tuyere portion S5 is, if that can be set down as bosh portion S4 'and the tuyere section S5' (see FIG. 2), and more downward with respect to the lower edge position E _L described above The lower edge position E _L ′ can be set to In this case, the lower edge position E _{L 'is} set on an extension of a line connecting the original lower edge position E _L on the edge position E _U, from the center H0 tuyeres 5 lower edge position E _L' dimensions to H1 ' The dimension D1 ′ from the tip D0 of the tuyere 5 to the lower edge position E _L ′ is obtained. These dimensions H1 ′ and D1 ′ are also within the numerical ranges of the dimensions H1 and D1 described above.

In the above embodiment, when the morning glory stave 10 is arranged in the blast furnace 1, each protrusion 12 is continuously annular, but may be discontinuous to each other, The structure etc. which are arranged in a different zigzag may be sufficient. However, circumferential balance is important for the operation of the blast furnace 1, and consideration should be given so that symmetry is obtained with respect to the center of the blast furnace 1.
The protrusions 12 may be formed on the surface of the morning glory portion stave 10, or another member that becomes a protrusion on the furnace inner surface may be installed separately from the stave. In the present embodiment, it is more preferable to form the protrusion 12.

In the above-described embodiment, the piping 16 for cooling is formed on the morning glory portion stave 10 including the protruding portion 12, but the protruding portion 12 may be omitted. However, it is possible to promote the formation of the deposit 7 by lowering the temperature of the surface of the protrusion 12 and also to adjust the increase / decrease of the deposit 7 by controlling the temperature, and to stably maintain the profile of the surface in the furnace. And the life of the protrusion can be extended.
In addition, the arrangement of the protrusions 12, the cross-sectional shape, the arrangement of the cooling pipes 16, the overall shape and dimensions of the stave 10 may be appropriately selected in the implementation.

DESCRIPTION OF SYMBOLS 1 ... Blast furnace 2 ... Furnace body 2A ... Iron skin 2B, 2C ... Stave 2D, 2E ... Refractory brick 3 ... Gas collection mantel 4 ... Charge 4A ... Massive band 4B ... Fusion zone 4C ... Dripping zone 4D ... Core 5 ... tuyere 5A ... hot air 5B ... raceway 6 ... tapping outlet 6A ... iron 6B ... hot metal 7 ... deposit 9 ... blast furnace morning glory structure 10 ... stave for morning glory part 11 ... stave body 12 ... projection 13 ... standard piping plan 16 ... cooling a surface 20 ... firebrick D0 ... tuyere tip position D1 ... dimension E L _... bosh stave lower edge from tuyere tip to the lower edge position of the bosh section E U _... bosh stave upper edge H0 ... tuyere center height H1 ... dimension from the tuyere center to the lower edge position of the morning glory part H2 ... dimension from the tuyere center to the upper edge position of the morning glory part S1 ... furnace mouth part S2 ... shaft part S3 ... furnace Abdomen S4 ... morning glory S5 ... tuyere S6 ... hearth

Claims (4)

A cylindrical morning glory structure that is provided between the tuyere of the blast furnace and the furnace belly and expands in the vertical direction upward,
The morning glory portion has an annular iron skin, a copper or copper alloy morning glory stave provided on the inner periphery of the iron skin, and a refractory brick provided on the inner periphery of the morning glory stave. And
The horizontal thickness of the refractory brick at the upper edge position of the morning glory portion is 50 to 250 mm;
The horizontal thickness of the refractory brick at the lower edge position of the morning glory is 200 to 500 mm;
The narrow angle formed between the surface of the morning glory stave and the horizontal plane is 75 to 82 ° when the morning glory is viewed in a cross-section including its axis;
Blast furnace morning glory structure characterized by that. The vertical dimension from the center of the tuyere provided at the tuyere to the lower edge position of the morning glory is 1200 to 1350 mm;
The horizontal dimension from the tip of the tuyere to the lower edge position of the morning glory is 700-1100 mm;
The blast furnace morning glory structure of Claim 1 characterized by the above-mentioned.   The blast furnace morning glory according to claim 1 or 2, wherein a vertical dimension from the center of the tuyere provided at the tuyere portion to the upper edge position of the morning glory portion is 4500 mm to 5500 mm. Part structure. A tuyere, a furnace belly part, and a cylindrical morning glory part that is provided between the tuyere part and the furnace belly part and expands in the vertical direction upward,
The morning glory part has an annular iron skin, a copper or copper alloy morning glory stave provided on the inner periphery of the iron skin, and a refractory brick provided on the inner circumference of the morning glory stave. A blast furnace design method,
The horizontal thickness of the refractory brick at the upper edge position of the morning glory is 50 to 250 mm;
The horizontal thickness of the refractory brick at the lower edge position of the morning glory is 200 to 500 mm;
The narrow angle formed by the surface of the morning glory portion stave and a horizontal plane when the morning glory portion is viewed in a cross section including the axis thereof is set to 75 to 82 °;
A blast furnace design method characterized by that.

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