JP6413619B2 - Raw material charging device for bellless blast furnace, designing method for raw material charging device for bellless blast furnace, and manufacturing method for raw material charging device for bellless blast furnace - Google Patents

Description

  The present invention relates to a raw material charging device for a bell-less blast furnace, a method for designing a raw material charging device for a bell-less blast furnace, and a manufacturing method for a raw material charging device for a bell-less blast furnace. The raw material charging device of the bell-less blast furnace that can suppress the eccentricity of the raw material flux by only devising the shape of the vertical chute without making a movable device above the vertical chute, The present invention relates to a method for designing a raw material charging device for a bell-less blast furnace and a method for manufacturing a raw material charging device for a bell-less blast furnace.

  A bellless blast furnace raw material charging apparatus that charges raw materials at the top of the blast furnace includes a furnace top hopper, a collecting chute, a vertical chute, and a swivel chute. As such a raw material charging apparatus, a parallel hopper type raw material charging apparatus in which furnace top hoppers are arranged in parallel is known. In the parallel hopper type raw material charging device, the raw material particles cut out from the hopper have a lateral velocity component when falling from the collecting chute to the vertical chute. This decenters the raw material flux within the vertical chute. This causes a circumferential deviation of the discharge amount of the raw material discharged from the turning chute.

  In order to prevent the raw material flux from being decentered in the vertical chute, it is effective to reduce the inner diameter of the vertical chute. However, reducing the inner diameter of the vertical chute causes the chute to be blocked by the raw material. Since the blast furnace becomes inoperable when the chute is closed, the vertical chute is designed with a certain allowance for the raw material flow rate.

  Further, several methods have been proposed in order to suppress the eccentricity of the raw material flux in the vertical chute without reducing the inner diameter of the vertical chute (Patent Documents 1, 2, and 3).

  For example, Patent Document 1 proposes a method of dispersing a raw material flux by providing a diverting projection in a collecting chute to prevent the raw material flux from being eccentric in a vertical chute. However, in this method, a large amount of raw material accumulates in the collecting chute. In the collective chute, auxiliary devices such as a seal valve driving device and a vibration sensor for detecting the raw material flow are installed, and the accumulated raw materials hinder the operation of these auxiliary devices. For this reason, it is not preferable to increase the amount of raw material accumulated in the collective chute.

  Patent Documents 2 and 3 propose a method of suppressing the eccentricity of the raw material flux by installing a movable device on the upper part of the vertical chute and controlling it. However, these methods not only increase the cost of the movable device itself, but also require an extra length of the vertical chute for the installation of the device that drives the movable part. It becomes necessary to install itself in a high position, and the equipment cost of the blast furnace itself becomes high.

Japanese Patent No. 3799987 Japanese Patent No. 2921777 Japanese Patent No. 3777654

  The present invention has been made in view of the above circumstances, and devise only the shape of the vertical chute without increasing the amount of raw material accumulated in the collective chute and without installing a movable device on the vertical chute. The main purpose is to suppress the eccentricity of the raw material flux.

  As a result of calculating the discharge behavior of the raw material from the collective chute using a DEM (Discrete Element Method), the present inventors have found that the raw material discharged from the collective chute collides with the inner wall surface of the upper part of the vertical chute. The horizontal velocity component disappears and falls almost directly below.In addition, the slightest inclination of the vertical chute has a horizontal velocity opposite to the horizontal velocity when discharged from the collective chute. It was found that the raw material was fed back into the center of the vertical chute. The present invention has been made based on such knowledge, and the gist thereof is as follows.

  In order to solve the above-mentioned problem, in the present invention, there is provided a raw material charging device for a bell-less blast furnace having a collective chute, a vertical chute, and a swivel chute that are arranged in sequence from the top under the furnace top hopper, the collective chute The raw material falling surface is inclined with respect to a horizontal plane at an angle smaller than the angle of repose of the raw material to be used, and is lowered so as to approach the lower end opening of the collective chute, and the collective chute is fixed to the vertical chute. The side surface of the vertical chute is formed at an inclination angle that passes through the center of the inner diameter of the lower end surface of the vertical chute when the material that has fallen along the material falling surface of the collective chute collides with the side surface. A raw material charging apparatus for a bell-less blast furnace is provided.

  According to the present invention, the flow rate of the raw material can be increased only by devising the shape of the vertical chute without increasing the accumulation amount of the raw material in the collective chute and without installing a movable device on the vertical chute. The bundle can be prevented from being eccentric.

  In the said invention, it is preferable that the raw material fall surface of the said collection chute has the smoothness of the grade which does not change the flow of a raw material. This is because it is possible to preferably avoid increasing the amount of raw material accumulated in the collecting chute.

  In the present invention, the vertical chute has an upper tube and a lower tube, the collective chute is fixed to the upper tube of the vertical chute, and the upper end inner diameter of the upper tube of the vertical chute is Da [m ], The lower end inner diameter of the upper tube of the vertical chute is Db [m], the length of the upper tube of the vertical chute is La [m], and the length of the lower tube of the vertical chute is Lb [m]. When it does, it is preferable to satisfy | fill following formula (1)-(3).

  This is because, in any raw material flow rate in normal use of the vertical chute, the effect of suppressing the eccentricity of the raw material flux can be optimized.

  Further, in the present invention, a method for designing a raw material charging apparatus of a bell-less blast furnace for designing the raw material charging apparatus, wherein the vertical chute has an upper pipe and a lower pipe, and the collective chute is the vertical The vertical chute is fixed to the upper pipe of the chute, and the upper chute of the upper pipe of the vertical chute is Da [m], the lower chute of the upper pipe of the vertical chute is Db [m], and the vertical chute When the length of the upper tube is La [m] and the length of the lower tube of the vertical chute is Lb [m], it is designed to satisfy the above formulas (1) to (3). A method of designing a raw material charging apparatus for a bell-less blast furnace is provided.

  According to the present invention, in any raw material flow rate in normal use of the vertical chute, the effect of suppressing the eccentricity of the raw material flux can be optimized.

  Moreover, in this invention, the manufacturing method of the raw material charging device of a bell-less blast furnace characterized by having the design process using the said design method is provided.

  According to the present invention, in any raw material flow rate in normal use of the vertical chute, the effect of suppressing the eccentricity of the raw material flux can be optimized.

  In the present invention, the flux of the raw material is decentered by devising only the shape of the vertical chute without increasing the amount of raw material accumulated in the collective chute and without installing a movable device above the vertical chute. There is an effect that this can be suppressed.

It is a schematic sectional drawing which shows the whole of an example of the raw material charging device of the bell-less blast furnace of this invention. It is a schematic sectional drawing which shows the collection chute and the vertical chute in the raw material charging apparatus of the bell-less blast furnace shown in FIG. It is a schematic sectional drawing which expands and shows the vertical chute | shoot shown by FIG. It is a schematic sectional drawing which shows the change accompanying the change of (theta) ₁ / (theta) ₂ of the shape of the vertical chute | shoot shown by FIG. This is an example in which the radial fall frequency distribution of the raw material particles at the lower end of the lower tube of the vertical chute and the cumulative distribution thereof are derived by simulation for each θ ₁ / θ ₂ . is a diagram showing changes in mainstream position of raw material by θ _{1 /} θ ₂ for each F / F _{MAX (ratio} volume flow designed volume flow rate of the raw material of the vertical chute). It is a diagram showing a graph representing for F _{/ F MAX} to _{(θ 1 / θ 2) opt} . For the raw material charging devices of Example 1, Comparative Example 1, and Comparative Example 2, a simulation using DEM was performed, and the behavior of the raw material particles falling on the raw material falling surface of the collecting chute was described. FIG.

  Hereinafter, the bellless blast furnace raw material charging apparatus, the bellless blast furnace raw material charging apparatus design method, and the bellless blast furnace raw material charging apparatus manufacturing method of the present invention will be described in detail.

A. The raw material charging device of the bell-less blast furnace of the present invention is a raw material charging device of the bell-less blast furnace having a collective chute, a vertical chute, and a swirling chute that are arranged in order from the top under the furnace top hopper. It is characterized by the following points. The raw material dropping surface of the collective chute is inclined at an angle smaller than the angle of repose with respect to the horizontal plane so as to decrease as it approaches the lower end opening of the collective chute. The collective chute is fixed to the vertical chute. The side surface of the vertical chute is formed at an inclination angle that passes through the center of the inner diameter of the lower end surface of the vertical chute when the material that has fallen along the material falling surface of the collecting chute collides with the side surface. Yes.

  FIG. 1 is a schematic cross-sectional view showing an entire example of a raw material charging apparatus for a bell-less blast furnace according to the present invention. FIG. 2 is a schematic cross-sectional view showing the collecting chute and the vertical chute in the raw material charging apparatus of the bell-less blast furnace shown in FIG. FIG. 2 shows a cross section passing through the center of the inner diameter of the collecting chute and the center of the inner diameter of the vertical chute.

  A bellless blast furnace raw material charging apparatus 100 shown in FIG. 1 includes a collecting chute 120, a vertical chute 130, and a swiveling chute 140 that are continuously provided below the top hopper 110 from the top. As shown in FIG. 2, the vertical chute 130 has an upper tube 130a and a lower tube 130b. The upper tube 130a and the lower tube 130b are continuous and fixed. The collecting chute 120 has a truncated conical cylinder shape. The raw material falling surface 120a of the collective chute 120 is inclined with respect to the horizontal plane so as to decrease as it approaches the lower end opening 120b of the collective chute 120 at an angle smaller than the repose angle of the raw material used. The collective chute 120 is fixed to the upper tube 130 a of the vertical chute 130. The upper tube 130a of the vertical chute 130 has a truncated conical cylinder shape. The inner wall surface (side surface) 130aa of the upper tube 130a of the vertical chute 130 is the center of the inner diameter of the lower end surface of the vertical chute 130 when the raw material falling along the raw material falling surface 120a of the collecting chute 120 collides with the inner wall surface 130aa. It is formed in the inclination angle which passes. In the vertical chute 130 shown in FIG. 2, the upper end inner diameter of the upper tube 130a of the vertical chute 130 is Da [m], the lower end inner diameter of the upper tube 130a of the vertical chute 130 and the inner diameter of the lower tube 130b are Db [m], The length of the upper tube 130a of the vertical chute 130 is La [m], and the length of the lower tube 130b of the vertical chute 130 is Lb [m].

  In the raw material charging apparatus 100 shown in FIG. 1, the raw material dropped from the furnace top hopper 110 onto the raw material falling surface 120a of the collective chute 120 as shown by the arrow is perpendicular to the collective chute 120 as shown by the arrow. It is discharged to the upper tube 130a of the chute 130 and falls to the lower end of the lower tube 130b of the vertical chute 130. At this time, the raw material flux passes through the center of the inner diameter of the lower end surface of the vertical chute 130. The raw material particles dropped to the lower end of the lower pipe 130 b of the vertical chute 130 are charged into the blast furnace furnace body 150 through the turning chute 140.

  In the raw material charging apparatus of the bell-less blast furnace according to the present invention, the side surface of the vertical chute falls along the raw material falling surface of the collective chute, like the inner wall surface (side surface) 130aa of the vertical chute 130 shown in FIG. When the raw material collides with the side surface, it is formed at an inclination angle so as to pass through the center of the inner diameter of the lower end surface of the vertical chute. For this reason, the flow rate of the raw material is eccentric only by devising the shape of the vertical chute without increasing the accumulation amount of the raw material in the collective chute and without installing a movable device on the vertical chute. Can be suppressed. Here, in this specification, the degree of eccentricity refers to that at the lower end of the lower pipe of the vertical chute.

  Hereinafter, the raw material charging apparatus for the bell-less blast furnace of the present invention will be described. The raw material charging apparatus for a bell-less blast furnace according to the present invention includes a collective chute, a vertical chute, and a swivel chute that are continuously provided below the top hopper.

1. Vertical chute The present invention is such that the side surface of the vertical chute passes through the center of the inner diameter of the lower end surface of the vertical chute when the material falling along the material falling surface of the collective chute collides with the side surface. It is formed at an inclination angle.

(1) Inner diameter of vertical chute The shape of the vertical chute is determined not only to have the characteristics regarding the inclination angle but also to satisfy the following restrictions on the inner diameter of the vertical chute.

a. The upper end inner diameter (Da [m]) of the upper pipe 130a of the vertical chute 130 is determined based on the design capacity of the blast furnace, the design volume flow rate of the raw material (F _MAX [m ³ / s]). Is determined in consideration of a design margin (for example, 50%) as the minimum diameter that can pass.

As an empirical formula representing the relationship between the upper end inner diameter (Da [m]) of the upper tube 130a of the vertical chute 130 and the volume flow rate (F [m ³ / s]) of the raw material of the vertical chute 130, for example, flow of granular solids through orifices, RT FOWLER and JR GLASTONRURY, Chemical Engineering Science, 1959, Vol. 10, PP. 150 to 156.). The formula described in Non-Patent Document 1 is known as a raw material discharge rate formula when raw material particles are discharged from holes (orifices) opened in a flat plate. The following formula (4) is obtained by applying the formula described in Non-Patent Document 1 to the raw material discharged from the collecting chute 120 to the upper pipe 130a of the vertical chute 130. The following formula (4) is the formula described in Non-Patent Document 1, and the hole (orifice) opened in the flat plate is used as the lower end opening of the collecting chute 120 (upper end opening of the upper tube 130a of the vertical chute 130) and opened in the flat plate. The flow rate of the raw material discharged from the hole (orifice) is the volume flow rate of the raw material discharged from the collecting chute 120 to the upper pipe 130a of the vertical chute 130.

In the above formula (4), F [m ³ / s] is the maximum volume flow rate of the raw material discharged from the collecting chute 120 to the upper pipe 130a of the vertical chute 130 (the maximum volume flow rate of the raw material passing through the upper end of the vertical chute 130). ). Further, α is a shape factor of the hole (orifice), and can be a value within a range of 0.222 to 0.270 depending on the shape of the hole, but the lower end opening of the collecting chute 120 is a circular hole. α is 0.222. Furthermore, A ^{[m 3]} flow path cross-sectional area of the lower end opening of the collecting chute ^{120 (πDa 2/4),} g [m / s 2] is the gravitational _{acceleration, D} p [m] is the particle diameter, Da [m ] Is the inner diameter of the upper end of the upper tube 130a of the vertical chute 130. Furthermore, λ is a shape factor of the raw material particles, and can be a value in the range of 1.00 to 1.54 depending on the shape of the particles, but is 1.33 for the raw material particles in the raw material charging apparatus 100. .

In the above formula (4), the value of Da obtained when F is set to F _MAX (designed volume flow rate of the raw material) determined based on the design capability of the blast furnace is the maximum value of Da that F _MAX can pass through. Small diameter. The actual value of Da is determined in consideration of the design margin (for example, 50%) in the minimum diameter of Da that can pass F _MAX .

  Specifically, Da is preferably 300 mm or more and 1200 mm or less. This is because if the particle size is smaller than 300 mm, the raw material particles (maximum particle size of about 80 mm) may form an arch and block the chute. Further, if it is larger than 1200 mm, it interferes with other furnace top equipment. More preferably, it is desirable to be 450 mm or more in consideration of an appropriate margin.

b. The lower end inner diameter of the upper tube of the vertical chute 130 The lower end inner diameter (Db [m]) of the upper tube 130a of the vertical chute 130 is the same as the upper end inner diameter (Da [m]) of the upper tube 130a of the vertical chute 130. Based on the capacity, the design volume flow rate (F _MAX [m ³ / s]) of the raw material is determined with a design margin (for example, 50%) in consideration of the minimum diameter that can be passed.

In order to derive the minimum value of Db through which the design volume flow rate (F _MAX [m ³ / s]) of the raw material can pass, for example, an equation of motion can be used. Equation (5) below assumes that the velocity of the raw material particles at the upper end of the upper tube 130a of the vertical chute 130 is zero, and that the raw material particles freely fall from the upper end to the lower end of the upper tube 130a of the vertical chute 130. This represents the passing speed when the raw material particles pass through the lower end of the upper tube 130a using the equation of motion. The following formula (6) represents the maximum volume flow rate of the raw material passing through the lower end of the upper tube 130a of the vertical chute 130 based on the following formula (5).

In the above formulas (5) and (6), v ₁ [m / s] is the passing speed when the raw material particles pass through the lower end of the upper tube 130a, g [m / s ² ] is the gravitational acceleration, and La [m ] Is the length of the upper pipe 130a of the vertical chute 130, and F [m ³ / s] is the maximum volume flow rate of the raw material passing through the lower end of the upper pipe 130a of the vertical chute 130 (the raw material passing through the middle part of the vertical chute 130). Db [m] is the lower end inner diameter of the upper tube 130a of the vertical chute 130.

In the above formula (6), the value of Db obtained when F is set to F _MAX (designed volume flow rate of the raw material) determined based on the design capacity of the blast furnace is the maximum value of Db that F _MAX can pass through. Small diameter. The actual value of Db is determined by taking into account the design margin (for example, 50%) in the minimum diameter of Db through which F _MAX can pass.

  Specifically, Db is preferably 300 mm or more and 1000 mm or less, and particularly preferably 300 mm or more and 800 mm or less. This is because if the particle size is smaller than 300 mm, the raw material particles (maximum particle size of about 80 mm) may form an arch and block the chute. Further, since the inner diameter of the turning chute in the furnace is approximately 1000 mm or less, if Db is larger than 1000 mm, the raw material may overflow from the turning chute. This is because, if it is larger than 800 mm, the raw material may overflow from the turning chute.

(2) Vertical Chute Length The shape of the vertical chute is determined not only to have the characteristics regarding the tilt angle but also to satisfy the following restrictions on the length of the vertical chute.

  In the vertical chute, the sum of La and Lb is designed to be as short as possible in consideration of the balance between the furnace top hopper and the swivel chute equipment. This is because an unnecessary increase in the total of La and Lb causes an increase in the construction cost of the blast furnace itself. Considering these, generally, the total of La and Lb is preferably 2500 mm or more and 5000 mm or less.

  Moreover, La needs to be long enough for the raw material discharged from the collecting chute to collide with the inclination of the upper part of the vertical chute. If La is shorter than Da, the raw material discharged from the collecting chute will fall without colliding with the inclination of the upper part of the vertical chute. Accordingly, La is equal to or greater than Da. Considering these, generally, La is preferably 300 mm or more and 2000 mm or less.

  As described above, in the vertical chute, the sum of Da, Db, La, and Lb, and the range of La are related to the constraints of the blast furnace body that are different from the features of the present invention, or the features of the present invention. It is determined by the constraint condition. Da, Db, La, and Lb are parameters that determine the inclination of the inner wall surface of the vertical chute described later relatively freely.

(3) Inclination of the inner wall surface of the vertical chute The raw material charging device for the bell-less blast furnace of the present invention has the above-mentioned characteristics regarding the inclination angle and satisfies the above restrictions on the shape of the vertical chute. Although not particularly limited, those having the following characteristics regarding the inclination of the inner wall surface of the vertical chute are preferable.

  Specifically, as the raw material charging apparatus for the bell-less blast furnace according to the present invention, the vertical chute has an upper pipe and a lower pipe, the collective chute is fixed to the upper pipe of the vertical chute, and the vertical chute The upper end inner diameter of the upper tube is Da [m], the lower end inner diameter of the upper tube of the vertical chute is Db [m], the length of the upper tube of the vertical chute is La [m], and the upper length of the vertical chute is When the length of the lower tube is Lb [m], those satisfying the following formulas (1) to (3) are preferable. By satisfying the following formulas (1) to (3), the inclination angle of the side surface of the vertical chute is such that the raw material falling along the raw material falling surface of the collective chute collides with the side surface. The inclination angle is such that it passes through the center of the inner diameter of the lower end surface.

FIG. 3 is an enlarged schematic sectional view of the vertical chute shown in FIG. FIG. 4 is a schematic cross-sectional view showing a change associated with a change in θ ₁ / θ ₂ of the shape of the vertical chute shown in FIG. The physical meaning of the above formulas (1) to (3) will be described with reference to enlarged sectional views of the vertical chute shown in FIGS.

First, the relationship between the shape of the vertical chute 130 shown in FIG. 3 and θ ₁ and θ ₂ shown in the above equations (1) and (2) will be described. In FIG. 3, the center line of the inner diameter of the upper tube 130a and the lower tube 130b of the vertical chute 130 is L1, and the inner diameter of the lower tube 130b of the lower tube 130b of the vertical chute 130 is from the upper end of the inner wall surface 130aa of the upper tube 130a of the vertical chute 130. A straight line connecting the centers 130e is indicated by L2, and an extension line of the inner wall surface 130aa of the upper pipe 130a of the vertical chute 130 is indicated by L3. As can be seen from the figure, θ ₁ represented by the above equation (1) is the gradient of L3 with respect to L1. Further, θ ₂ represented by the above formula (2) is a gradient of L2 with respect to L1. Further, θ ₁ / θ ₂ represented by the above formula (3) means the ratio of θ _{1 to} θ ₂ .

As shown in FIG. 4, when θ ₁ / θ ₂ <1, the gradient of L3 (θ ₁ ) with respect to L1 is smaller than the gradient of L2 with respect to L1 (θ ₂ ). Therefore, L3 passes through a position closer to the starting point of L3 than the center 130e of the inner diameter of the lower end surface at the lower end surface of the lower tube 130b of the vertical chute 130. When θ ₁ / θ ₂ = 1, the slope (θ ₁ ) of L3 with respect to L1 matches the slope (θ ₂ ) of L2 with respect to L1. Therefore, L3 passes through the center 130e of the inner diameter of the lower end surface at the lower end surface of the lower tube 130b of the vertical chute 130. When θ ₁ / θ ₂ > 1, the slope (θ ₁ ) of L3 with respect to L1 is larger than the slope (θ ₂ ) of L2 with respect to L1. Therefore, L3 passes through a position farther from the starting point of L3 than the center 130e of the inner diameter of the lower end surface on the lower end surface of the lower tube 130b of the vertical chute 130.

  Next, the behavior when the raw material particles discharged from the collecting chute 120 to the upper tube 130a fall to the lower end of the lower tube 130b of the vertical chute 130 depends on the shape change of the vertical chute 130 shown in FIG. How it changes. Then, a preferable shape of the vertical chute 130 will be described. In the following description, using DEM (Discrete Element Method), raw material particles dropped on the raw material falling surface of the collective chute 120 are discharged from the collective chute 120 to the upper pipe 130a of the vertical chute 130, This is based on the result of a simulation describing the behavior when the vertical chute 130 drops to the lower end of the lower tube 130b. The simulation using the DEM depends on patent documents (Japanese Patent Laid-Open Nos. 2012-37937 and 549138).

FIG. 5 shows an example in which the radial drop frequency distribution of the raw material particles at the lower end of the lower tube of the vertical chute and the integrated distribution thereof are derived by the above simulation for each θ ₁ / θ ₂ . In FIG. 5, the value of the dimensionless position on the X axis is the ratio of the distance from the radial center 130e to the inner radius (Db / 2) of the lower tube 130b, which is 0 at the center 130e and at the vertical chute 130. It is -1 on the inner wall surface of the lower pipe 130b on the raw material inflow side, and +1 on the inner wall surface of the lower pipe 130b on the opposite side. Further, the Y-axis fall frequency distribution is a frequency distribution representing the frequency at which the raw material particles pass through the lower end surface of the lower tube 130b of the vertical chute 130. The integrated distribution of the fall frequency on the Y axis is obtained by integrating the fall frequency distribution from the negative side of the dimensionless position. Further, in FIG. 5, the position of the lower end of the lower tube 130b of the vertical chute 130 (hereinafter, abbreviated as “main stream position of the raw material”) at which the frequency of the raw material particle dropping is the highest is a dotted line for each θ ₁ / θ ₂ . It is shown in

FIG. 6 is a diagram showing changes in the mainstream position of the raw material according to θ ₁ / θ ₂ for each F / F _MAX (ratio of the volume flow rate of the raw material of the vertical chute to the design volume flow rate). From FIG. 6, the main flow position shifts to the raw material inflow side in the vertical chute 130 as θ ₁ / θ ₂ increases at the same flow rate, while the main flow position increases as the flow rate increases at the same θ ₁ / θ _2. It turns out that it transfers to the raw material inflow side in 130. FIG.

Based on FIG. 6, θ ₁ / θ ₂ ((θ ₁ / θ ₂ ) opt) where the dimensionless position value representing the mainstream position of the raw material becomes 0, and F _MAX (the raw material design volume of the vertical chute 130). FIG. 7 shows the result of the relationship between the ratio (F / F _MAX ) of F (volume flow rate of the raw material of the vertical chute 130) to the flow rate). FIG. 7 is a graph showing (θ ₁ / θ ₂ ) opt with respect to F / F _MAX .

When the range of F in normal use of the vertical chute 130 is F _MAX or less, F / F _MAX ≦ 1.0. For this reason, as shown in FIG. 7, within the range of F in the normal use of the vertical chute 130, the range that (θ ₁ / θ ₂ ) opt can take is 0.6 or more.

Further, when θ ₁ / θ ₂ = 1.0, as described above, L3 passes through the center 130e of the inner diameter of the lower end surface at the lower end surface of the lower tube 130b of the vertical chute 130. That is, regardless of the value of F / F _MAX, the effect of suppressing the eccentricity of the raw material is excessive. Therefore, in principle, θ ₁ / θ ₂ needs to satisfy θ ₁ / θ ₂ ≦ 1.0 regardless of the value of F / F _MAX . Then, considering the effect of suppressing the eccentricity of the raw material at the lower limit of F in normal use of the vertical chute 130, θ ₁ / θ ₂ needs to satisfy θ ₁ / θ ₂ ≦ 0.85. For this reason, as shown in FIG. 7, within the range of F in the normal use of the vertical chute 130, the range that (θ ₁ / θ ₂ ) opt can take is 0.85 or less.

Therefore, within the range of F in the normal use of the vertical chute 130 shown in FIG. 3, the range that (θ ₁ / θ ₂ ) opt can take is 0.6 or more and 0.85 or less. Therefore, in the vertical chute 130 shown in FIG. 3, when 0.6 ≦ θ ₁ / θ ₂ ≦ 0.85, the vertical chute 130 is always in any of the ranges of F in the normal use of the vertical chute 130. The value representing the main flow position of the raw material can be 0, and the main flow position of the raw material can be the center 130e of the inner diameter of the lower end surface of the lower pipe 130b of the vertical chute 130. That is, the effect of suppressing the eccentricity of the raw material flux can be optimized. Therefore, the vertical chute 130 shown in FIG. 3 preferably satisfies the above formulas (1) to (3).

When the vertical chute 130 shown in FIG. 3 is actually designed, in the graph shown in FIG. 7, (θ ₁ / θ ₂ ) at F (volume flow rate of the raw material of the vertical chute 130) that is most frequently used in the graph shown in FIG. ) The value of opt is obtained, and the gradient (θ ₁ ) of L3 with respect to L1 may be set based on the value.

  From the above, it is preferable that the vertical chute satisfies the above formulas (1) to (3) like the vertical chute 130 shown in FIG. This is because, in any raw material flow rate in normal use of the vertical chute, the effect of suppressing the eccentricity of the raw material flux can be optimized.

In the vertical chute, θ ₁ is not particularly limited as long as it satisfies the above expressions (1) to (3), but it satisfies tan 0 ° ≦ θ ₁ ≦ tan 45 °. In particular, those satisfying tan 0 ° ≦ θ ₁ ≦ tan 30 ° are preferable. This is because the inclination of the inner wall surface of the vertical chute is large, and when the inner wall surface of the vertical chute approaches horizontal, the raw material accumulates on the vertical chute and the intended effect cannot be exhibited.

2. Collective chute The collective chute of the present invention is inclined such that the raw material falling surface of the collective chute is lower than the angle of repose with respect to a horizontal plane so as to approach the lower end opening of the collective chute, and the vertical chute Is fixed. Here, the “rest angle” means an angle of a slope that starts to collapse spontaneously when the raw material particles are stacked.

  As described above, the material dropping surface of the collective chute is inclined at an angle smaller than the angle of repose with respect to the horizontal plane as described above. Can be stacked until formed. Thereby, it is possible to reduce the raw material falling directly on the raw material falling surface of the collective chute, and to avoid the raw material falling surface of the collective chute being scraped.

  The collective chute is not particularly limited, but it is preferable that the raw material falling surface of the collective chute has smoothness that does not change the flow of the raw material. This is because it is possible to preferably avoid increasing the amount of raw material accumulated in the collecting chute. Here, “smoothness that does not change the flow of the raw material” means that a convex portion or a concave portion that changes the flow by diverting the raw material falling on the raw material falling surface of the collective chute is formed on the raw material falling surface of the collective chute. It means not formed. For this reason, the raw material falling surface of the collective chute may be formed with a convex portion or a concave portion that is small enough not to divert the raw material dropped on the raw material falling surface of the collective chute and change the flow. As a convex part or a recessed part formed in the raw material fall surface of the said collection chute, the convex part or recessed part for a self-lining can be mentioned, for example. When a convex portion or a concave portion for self lining is formed on the raw material falling surface of the collective chute, the raw material particles dropped on the raw material falling surface of the collective chute are caused by the convex portion or concave portion. It becomes easy to collect on the raw material dropping surface. Thereby, it is possible to reduce the raw material falling directly on the raw material falling surface of the collective chute, and to avoid the raw material falling surface of the collective chute being scraped.

  The angle at which the raw material falling surface of the collective chute is inclined with respect to the horizontal plane is not particularly limited as long as it is an angle smaller than the repose angle of the raw material. Specifically, it is 0 ° or more and 30 ° or less. What is necessary is just to be 15 degrees or more and 25 degrees or less especially. This is because the effect of self-flying is preferably exhibited by setting the inclination to a repose angle or less of the raw material.

3. Swivel chute and furnace top hopper The swivel chute and furnace top hopper in the present invention are not particularly limited as long as they are normally used.

B. A method for designing a raw material charging apparatus for a bell-less blast furnace according to the present invention is a method for designing a raw material charging apparatus for a bell-less blast furnace for designing the raw material charging apparatus, wherein the vertical chute is used. Has an upper tube and a lower tube, the collecting chute is fixed to the upper tube of the vertical chute, and the vertical chute has an upper end inner diameter Da [m] of the upper chute of the vertical chute. When the lower end inner diameter of the upper tube is Db [m], the length of the upper tube of the vertical chute is La [m], and the length of the lower tube of the vertical chute is Lb [m], It is designed to satisfy (1) to (3).

According to the present invention, the value of (θ ₁ / θ ₂ ) opt at the volume flow rate of the raw material of the vertical chute most frequently used is obtained, and based on the value, the side surface of the upper pipe of the vertical chute is determined. The gradient (θ ₁ ) can be set. As a result, it is possible to suppress the eccentricity of the flux of the raw material only by devising the shape of the vertical chute at the volume flow rate of the raw material of the vertical chute that is used most frequently. The effect of suppressing the eccentricity to the bundle can be optimized. In addition, it is possible to always design the raw material charging apparatus that optimizes the effect of suppressing the eccentricity of the raw material flux at any raw material flow rate in the normal use of the vertical chute.

C. Method for manufacturing a raw material charging apparatus for a bell-less blast furnace The manufacturing method for a raw material charging apparatus for a bell-less blast furnace according to the present invention includes a design process using the above-described design method.

  According to the present invention, it is possible to manufacture the above-described raw material charging device that always optimizes the effect of suppressing the eccentricity of the raw material flux at any raw material flow rate in the normal use of the vertical chute.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

[Example 1]
In the raw material charging apparatus of the bell-less blast furnace of Example 1, the shapes of the collecting chute 120 and the vertical chute 130 in the raw material charging apparatus shown in FIG. 2 are as follows.
(Shape of collective chute)
The angle at which the material chute surface of the collecting chute is inclined with respect to the horizontal plane is set to be smaller than the angle of repose.
(Vertical chute shape)
-Values of Da and Db were appropriately selected so as to satisfy the restrictions described in the item "A. Raw material charging device of bellless blast furnace 1. Vertical chute (1) Inner diameter of vertical chute".
As values of La and Lb, A. Raw material charging equipment for bell-less blast furnace Vertical chute (2) Vertical chute length The value that satisfies the restrictions described in the item of “chute” was appropriately selected.
When θ ₁ / θ ₂ is calculated from the values of Da and Db and the values of La and Lb appropriately selected as described above, θ ₁ / θ ₂ = 0.723 (0.6 ≦ θ ₁ / θ ₂ ≦ 0.85).

[Comparative Example 1]
The raw material charging apparatus of the bell-less blast furnace of Comparative Example 1 is the same as that of Example 1 except that the shape of the vertical chute 130 is the following in the raw material charging apparatus shown in FIG. It is.
(Vertical chute shape)
-Values of Da and Db were appropriately selected so as to satisfy the restrictions described in the item "A. Raw material charging device of bellless blast furnace 1. Vertical chute (1) Inner diameter of vertical chute".
As values of La and Lb, A. Raw material charging equipment for bell-less blast furnace Vertical chute (2) Vertical chute length The value that satisfies the restrictions described in the item of “chute” was appropriately selected.
When θ ₁ / θ ₂ is calculated from the values of Da and Db and the values of La and Lb appropriately selected as described above, θ ₁ / θ ₂ = 0.290 (θ ₁ / θ ₂ <0.6) It became.

[Comparative Example 2]
The raw material charging apparatus of the bell-less blast furnace of Comparative Example 2 is the same as that of Example 1 except that the shape of the vertical chute 130 is the following in the raw material charging apparatus shown in FIG. It is.
(Vertical chute shape)
-Values of Da and Db were appropriately selected so as to satisfy the restrictions described in the item "A. Raw material charging device of bellless blast furnace 1. Vertical chute (1) Inner diameter of vertical chute".
As values of La and Lb, A. Raw material charging equipment for bell-less blast furnace Vertical chute (2) Vertical chute length The value that satisfies the restrictions described in the item of “chute” was appropriately selected.
When θ ₁ / θ ₂ is calculated from the values of Da and Db and the values of La and Lb appropriately selected as described above, θ ₁ / θ ₂ = 0.00 (θ ₁ / θ ₂ <0.6) It became.

[Evaluation]
Regarding the raw material charging apparatuses of Example 1, Comparative Example 1, and Comparative Example 2, the raw material particles dropped on the raw material falling surface 120a of the collective chute 120 using DEM (Discrete Element Method) are shown in FIG. A simulation was performed to describe the behavior of the vertical chute 130 that is discharged to the upper pipe 130a of the vertical chute 130 and dropped to the lower end of the lower pipe 130b of the vertical chute 130 shown in FIG. Specifically, a simulation was performed using a self-made DEM under the following simulation evaluation conditions.
<Simulation evaluation conditions>
-Shape of raw material particles = spherical-Size of raw material particles = average particle size 10 mm
-Apparent density of raw material particles = 3500 kg / m ³
・ G (gravity acceleration) = 9.8 m / s ²

  FIG. 8 shows the behavior of the raw material charging devices of Example 1, Comparative Example 1, and Comparative Example 2 when the raw material particles fall on the raw material falling surface of the collecting chute by performing a simulation using DEM. It is the figure which showed the image which described. In FIG. 8, images of Comparative Example 1, Comparative Example 2, and Example 1 are shown sequentially from the left side. In each of the images of Example 1, Comparative Example 1, and Comparative Example 2, the upper image shows the behavior observed from the side of the collective chute 120 and the vertical chute 130, and the lower image The image shows the amount of falling raw material particles at each position at the lower end of the lower tube 130b of the vertical chute 130. In the lower image, each position is indicated by a color closer to black as the amount of falling material particles decreases, and closer to white as it increases.

  From the image shown in FIG. 8, it can be seen that in the raw material charging apparatus of Comparative Example 1, the main flow position of the raw material is on the right side of the center 130e of the inner diameter of the lower end surface, and the raw material flux is eccentric. On the other hand, if the diameter is simply reduced, as shown in the image of Comparative Example 2, the main flow position of the raw material is still on the right side of the center 130e of the inner diameter of the lower end surface, and the effect of suppressing the eccentricity to the raw material flux is suppressed. It can be seen that is lacking. Furthermore, in the raw material charging apparatus of Comparative Example 2, there is also a tendency that the raw material particles block the lower end opening of the collecting chute 120 (the upper end opening of the upper pipe 130a of the vertical chute 130). On the other hand, in the raw material charging apparatus of the first embodiment, the main flow position of the raw material is near the center 130e of the inner diameter of the lower end surface of the lower pipe 130b of the vertical chute 130, and the effect of suppressing the eccentricity to the raw material flux is optimal. I understand that

  DESCRIPTION OF SYMBOLS 100 ... Raw material charging apparatus of bell-less blast furnace, 110 ... Furnace top hopper, 120 ... Collecting chute, 130 ... Vertical chute, 140 ... Turning chute

Claims (5)

A bellless blast furnace raw material charging device having a collective chute, a vertical chute, and a swivel chute arranged in order from the top under the furnace top hopper,
The material dropping surface of the collective chute is inclined at an angle smaller than the angle of repose with respect to the horizontal plane so as to decrease as it approaches the lower end opening of the collective chute,
The collective chute is fixed to the vertical chute,
The side surface of the vertical chute is formed at an inclination angle that passes through the center of the inner diameter of the lower end surface of the vertical chute when the material that has fallen along the material falling surface of the collecting chute collides with the side surface. A raw material charging device for a bell-less blast furnace, characterized in that   The raw material charging device of the bell-less blast furnace according to claim 1, wherein the raw material falling surface of the collective chute has smoothness that does not change the flow of the raw material. The vertical chute has an upper tube and a lower tube;
The collective chute is fixed to the upper pipe of the vertical chute,
The upper inner diameter of the upper tube of the vertical chute is Da [m], the lower end inner diameter of the upper tube of the vertical chute is Db [m], the length of the upper tube of the vertical chute is La [m], and the vertical chute The θ ₁ and θ ₂ shown in the following formulas (1) and (2) satisfy the following formula (3) when the length of the lower pipe of the chute is Lb [m]. A raw material charging apparatus for a bell-less blast furnace according to claim 1 or 2.
Where θ ₁ is the slope of the side of the upper tube of the vertical chute relative to the centerline of the inner diameter of the upper and lower tubes of the vertical chute, and θ ₂ is the upper tube of the vertical chute. The straight line connecting the upper end of the inner wall surface to the center of the inner diameter of the lower end surface of the lower pipe of the vertical chute is the gradient with respect to the center line, and θ ₁ / θ ₂ is the ratio of θ _{1 to} θ ₂ . A method for designing a raw material charging device for a bell-less blast furnace for designing the raw material charging device according to claim 1,
The vertical chute has an upper tube and a lower tube;
The collective chute is fixed to the upper pipe of the vertical chute,
The vertical chute has an upper end inner diameter of the upper chute of the vertical chute Da [m], a lower end inner diameter of the upper chute of the upper chute Db [m], and a length of the upper pipe of the vertical chute La [ m], when the length of the lower pipe of the vertical chute is Lb [m], θ ₁ and θ ₂ shown in the following formulas (1) and (2) satisfy the following formula (3) A method for designing a raw material charging apparatus for a bell-less blast furnace, characterized by being designed.
Where θ ₁ is the slope of the side of the upper tube of the vertical chute relative to the centerline of the inner diameter of the upper and lower tubes of the vertical chute, and θ ₂ is the upper tube of the vertical chute. The straight line connecting the upper end of the inner wall surface to the center of the inner diameter of the lower end surface of the lower pipe of the vertical chute is the gradient with respect to the center line, and θ ₁ / θ ₂ is the ratio of θ _{1 to} θ ₂ .   A method for manufacturing a raw material charging apparatus for a bell-less blast furnace, comprising a design process using the design method according to claim 4.