JPH0696723B2 - Method of charging raw material into blast furnace - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a method for charging a raw material discharged from a hopper into a blast furnace through a swirling chute whose swirling radius can be changed, and particularly to a method for charging the raw material into the blast furnace. The present invention relates to a method for charging raw materials into a blast furnace capable of improving the uniformity of charging.

[Prior art]

In a blast furnace such as a bellless blast furnace or a general shaft furnace that feeds raw material from the top, a swirling chute that performs swirling operation while adjusting the opening of the raw material flow rate control gate (hereinafter referred to as flow control gate) is used. The raw materials are being charged into the blast furnace. In such a method of charging the raw material into the blast furnace, conventionally, the accuracy of controlling the total amount of the raw material charged into the blast furnace is improved, and the uniformity of the charging of the raw material into the blast furnace is improved. , Various techniques for improving the control accuracy of the total charging time are disclosed. In Japanese Patent Laid-Open No. 54-31005, optimum flow control gate opening and swirling chute swirling speed are determined based on the conditions and distribution pattern of the raw material charged into the blast furnace and the characteristics of the raw material outflow. Disclosed is a method for charging a raw material into a blast furnace in which raw material charging is controlled by a digital actuator connected to a flow control gate opening / closing mechanism and a stepping motor connected to a swinging mechanism of a swing chute by a pulse signal according to Has been done. In Japanese Patent Laid-Open No. 59-229407, the flow control gate opening is corrected at the next raw material charging based on the average value and the dispersion value of the difference between the measured value and the set value of the raw material discharging time at the past plural chargings. On the other hand, on the other hand, the flow adjustment gate opening for each raw material charging, which is determined in advance from the raw material cutting amount, brand and charging pattern, etc. Determine the required adjustment gate opening setting amount, and from this and the flow adjustment gate opening correction amount, obtain the flow adjustment gate opening set value at the time of the next raw material charging, and according to this, set the flow rate at the next raw material charging. A technique of controlling the opening of the adjusting gate is disclosed. In JP-A-61-238906, before charging the raw material into the blast furnace, based on the actual measurement value of the raw material weight at the previous charging of the raw material and the actual measurement value of the raw material cutting time from the upper hopper, Calculate the raw material discharge speed, calculate the number of swirling chutes required to discharge the raw material of the planned weight at the time of the next raw material charging at the same discharge speed, and then calculate the number of gyrations and the next raw material charging. A technique is disclosed in which the flow control gate opening is set in accordance with the difference between the planned number of times of determined turns and the time. In Japanese Patent Laid-Open No. 63-15083, the weight of the raw material on the turning chute is obtained as a corrected value in consideration of the influences of the turning position and the tilting angle to improve the accuracy of the weight measurement of the raw material on the turning chute. A technique is disclosed in which the opening degree of the flow control gate under the upper hopper and the turning speed of the turning chute are adjusted based on the new weight thus obtained. On the other hand, in order to make the distribution of the raw material charge distribution on the upper surface of the raw material in the blast furnace uniform, a turning chute with a variable turning radius was used, and the raw material was charged into the blast furnace while turning the turning chute. There is a technique in which the turning radius of the turning chute is changed during a certain period. FIG. 7 is a diagram showing a charging method when a conventional method for charging a raw material into a blast furnace, which uses a swirling chute whose swirling radius can be varied, is used for a raw material charging device. In FIG. 7, the raw material 1 to be charged into the blast furnace 10 is stored in the upper hopper 20. The flow control gate 22 supplies the raw material 1 to the swirling chute 24 by opening the flow control gate 22 according to the discharge speed W for a predetermined time. The swirling chute 24 is capable of varying the tilt angle θ while turning at an angular velocity ω, whereby the raw material 1 can be charged into the peripheral portion of the upper surface of the raw material in the blast furnace on the furnace wall side and the core portion. It is like this.

[Problems to be achieved by the invention]

However, in order to make the distribution amount of the raw material charging on the upper surface of the raw material in the blast furnace uniform, the raw material charging to the blast furnace which charges the raw material into the blast furnace by using the swirling chute whose swirling radius can be varied as described above is performed. In the charging method, there is a problem that a deviation of the charging amount occurs between the core portion on the furnace wall side on the upper surface of the raw material in the blast furnace and the core portion. In the raw material charging method for charging the blast furnace into the blast furnace through the turning chute whose turning radius can be changed, the turning chute of the turning chute is always kept at a constant rotation speed during one raw material charging period. It's spinning. Therefore, this turning radius is variable, and when the raw material is charged in the furnace wall side circumferential portion of the raw material upper surface in the blast furnace and when the raw material is charged in the core portion of the raw material upper surface in the blast furnace. Then, a great difference occurs in the peripheral velocity on the circular locus of the raw material dropping point. Therefore, particularly in the reactor core, there is a problem that the amount of charging with respect to the trajectory length per unit of the trajectory of the raw material dropping point increases. Further, conventionally, a method of determining the turning speed of the turning chute according to the total charging amount, the charging speed and the charging time has not been established. For this reason, for example, the raw material was charged at the same charging speed and the turning speed of the turning chute (the same turning speed with respect to the locus of the same raw material dropping point) despite the increase in the total charging amount. In some cases, even though some raw materials have not been charged yet, the charging end point on the charging trajectory is reached, and the remaining raw materials are charged into the core where the reactor reaction is active. There is a problem that it will end up. The techniques disclosed in the above-mentioned JP-A-54-31005, JP-A-59-229407, JP-A-61-238906 and JP-A-63-15083 are especially applicable to the charging of the raw material on the upper surface of the raw material in the blast furnace. Is not intended for uniformity. The present invention has been made to solve the above-mentioned conventional problems, and a blast furnace having a swirling chute capable of varying a swirling radius in order to make the amount of distribution of raw material charging on the upper surface of the raw material in the blast furnace uniform. In the method of charging the raw material into the blast furnace to be charged into the inside, accurately draw the charging locus covering the entire blast furnace without variation, and perform the stable raw material charging at each charging position in the blast furnace, and in particular, An object of the present invention is to provide a raw material charging method for a blast furnace, which can accurately control the charging amount in the core of the blast furnace and can control the charging time even if the charging amount is changed. .

[Means for achieving the object]

The present invention is a method for charging raw materials discharged from a hopper into a blast furnace through a swirling chute whose swirling radius can be changed, in a raw material charging method for a blast furnace, according to a predetermined total charging amount. , One of the charging speed and the charging time is determined in advance, and the other is obtained, and the turning peripheral speed of the turning chute is calculated according to the charging time and the total length of the trajectory of the drop point from the turning chute. The object is achieved by charging the raw material into the blast furnace at the charging speed while rotating the rotating chute at the rotating peripheral speed. Further, in the present invention, a reflective distance meter for detecting the position of the raw material falling from the turning chute is arranged, the turning radius at the raw material dropping point is obtained, and the raw material dropping is performed with reference to the turning radius at the raw material dropping point. By controlling the turning peripheral speed at a point to be the turning peripheral speed, the above problem is similarly achieved.

[Action]

FIG. 2 is a diagram showing an example of a locus of the raw material dropping point on the upper surface of the raw material in the blast furnace when the raw material 1 is charged with the turning radius varied. In FIG. 2, the locus of the raw material falling point on the upper surface of the raw material in the blast furnace is mainly composed of radius ro, radius 2ro and radius 3ro.
Made by two circles. In the locus of the raw material dropping point, Ls is the charging start point and Le is the charging end point. Further, La is the trajectory length when moving from the circular trajectory of radius 3ro to the circular trajectory of radius 2ro. Lb is the length of the locus when moving from the circular locus of radius 2ro to the circular locus of radius ro.
Further, L ₁ is the circumference length of the radius 3ro, L ₂ is the circumference length of the circle trajectory of the radius 2ro, and L ₃ is the circumference length of the circle trajectory of the radius ro. In this figure, the circumferential lengths L ₁ , L _2, and L ₃ can be expressed by the following equations, respectively. L ₁ = 3 × 2πro (1) L ₂ = 2 × 2πro (2) L ₃ = 2πro (3) Therefore, the total length L ₀ of the locus of the raw material drop point on the upper surface of the raw material in the blast furnace is Can be expressed as L ₀ = L ₁ + L ₂ + L ₃ + La + Lb = 3 × 2πro + 2 × 2πro + 2πro + La + Lb (4) As is apparent from the above formulas (1) to (3), the circumferential length L ₁
And the circumferential length L ₂ are respectively three times longer and twice longer than the circumferential length L ₃ , respectively. Further, the peripheral velocity V at the radius r of the raw material dropping point (the circumferential velocity at the circumference of the turning radius of the turning chute 24 and the fall distance of the raw material 1 from the turning chute 24) is the angular velocity at the radius r of the raw material dropping point. Can be expressed by the following equation. V = r × ω (5) Furthermore, the charging amount Wd per locus unit length of the raw material falling point is
From the above-mentioned peripheral speed V and the discharge speed W of the flow control gate 22, it is obtained from the following equation. Wd = W / V (6) The turning speed of the turning chute 24 is constant, that is, the angular velocity ω.
In the case where is constant during charging of the raw material, as is clear from the equation (6), the time of charging the raw material 1 into the core side of the blast furnace 10 (the smaller the radius r of the raw material dropping point) is, The peripheral velocity V at the raw material falling point becomes slow. Therefore, as the core of the blast furnace 10 increases, the charging amount Wd per locus unit length of the raw material dropping point increases. This state is apparent in the solid line in the graph showing the relationship between the charging locus L and the charging amount Wd in the lower part of FIG. That is, comparing the section with the circumferential length L _1, the section with the circumferential length L _{2 and} the section with the circumferential length L ₃ , there is a large difference in the charging amount Wd per locus unit length of the raw material dropping point. The shaded portion in this graph corresponds to the total charging amount W _{0 of the} raw material 1. In order to solve the problem of non-uniformity of the raw material charging distribution amount between the core portion of the blast furnace 10 and the furnace wall side circumferential portion, in the present invention, when the swirling chute 24 is swung, the circumferential speed of swirling is set. V is kept constant. As is clear from the above formula (6), by keeping the discharge speed W and the peripheral speed V at the material dropping point constant,
The charging amount Wd per locus unit length of the raw material dropping point can be made equal both in the core portion and in the circumferential portion on the furnace wall side. Here, in charging the raw material 1, the total charging amount W ₀ of the raw material 1
When the discharge speed W is given in advance and the total charging time T is not determined, the total charging time T is calculated by the following equation. T = W ₀ / W (7) When the total charging time T is given in advance, this total charging time T is used as it is. Using a turning chute that can change the turning radius,
When the raw material 1 is charged while turning the turning chute as shown in the locus shown in FIG. 2 and gradually decreasing the turning radius, the charging is started at the charging start point Ls in FIG. In addition, in order to complete the charging of the raw material 1 when the turning chute reaches the charging end point Le point, in order to finish the total length L ₀ of the falling point locus, the total charging time T, and the peripheral velocity V at the raw material falling point. The relationship shown in the following equation must be established between and. V = L ₀ / T (8) That is, the angular velocity ω of the turning chute 24 on the circular locus with the circumferential length L _1, the circular locus with the circumferential length L ₂ , and the circular locus with the circumferential length L _3.
As ω ₁ and ω ₂ respectively, as shown in the following three equations.
And ω ₃ makes it possible to uniformly charge the raw material as shown by the broken line in the graph showing the relationship between the charging locus L and the charging amount Wd in the lower part of FIG. 7. ω ₁ = V / 3ro (9) ω ₂ = V / 2ro (10) ω ₃ = V / ro (11) The turning chute 24 is turning at a constant peripheral speed as shown in FIG. 3 (A), This is as shown in (B). FIG. 3 (A) is a graph showing the relationship between the turning radius r of the turning chute and the turning rotational speed ω. Further, FIG. 3 (B) is a graph showing the relationship between the turning radius r of the turning chute and the peripheral velocity V of the locus of the dropping point of the raw material 1 that makes the turning rotation in the blast furnace. In these figures, the solid lines A ₁ and A ₂ show the characteristics when the peripheral speed is constant according to an example of the present invention, and the broken lines B ₁ and B ₂ show the characteristics when the conventional rotation speed is constant for comparison. The characteristics are shown. Further, the peripheral velocity V at the radius r of the raw material dropping point (the peripheral velocity at the circumference of the sum r of the radius of the swirling chute 24 and the falling distance of the raw material 1 from the swiveling chute 24) is as described later. Accuracy can be improved by obtaining the radius r of the material dropping point from the reflection type distance meter. As described above, the peripheral speed of the turning chute 24 is determined, and the turning chute 24 is rotated at this peripheral speed during the charging of the raw material 1, so that the turning chute 24 is charged when the charging end point Le reaches the charging end point Le. It is possible to finish charging all of the raw material 1 to be charged, and further improve the uniformity of the raw material charging distribution amount on the upper surface of the raw material in the blast furnace. The peripheral velocity in the claims of the present invention is not limited to the peripheral velocity V at the radius r of the raw material dropping point described above, but may be the peripheral velocity of the turning chute. Further, the present invention is not limited to the control in accordance with the peripheral speed for keeping the peripheral speed constant, but in order to intentionally make the raw material charging distribution amount on the upper surface of the raw material in the blast furnace non-uniform (insertion amount of a certain portion The peripheral speed may be changed during charging, in order to increase Also at this time, the total of the peripheral velocities at each time point (the integrated value of the peripheral velocities) is set to be the total length of the falling point locus at the end of the charging time.

【Example】

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of a raw material charging apparatus for a blast furnace in which the present invention is implemented. In FIG. 1, the raw material 1 to be charged into the blast furnace 10 is stored in the upper hopper 20. The flow control gate 22 supplies the raw material 1 to the swirling chute 24 by opening the flow control gate 22 according to the discharge speed W for a predetermined time. The swirling chute 24 is capable of varying the tilt angle θ while turning at an angular velocity ω, whereby the raw material 1 can be charged into the peripheral portion of the upper surface of the raw material in the blast furnace on the furnace wall side and the core portion. It is like this. The level meter 26 measures the distance l ₂ between the upper surface of the raw material 1 in the blast furnace 10 and the swirling chute 24 by, for example, a microwave length measuring sensor, and calculates the measured length l ₂ by the swirling chute rotation speed. Output to the container 50. The tilt control device 30 positions the servomotor 31 in accordance with the tilt angle command from the turning chute rotation speed calculator 50, whereby the turning chute is driven via the tilt drive mechanism 32.
24 is the commanded tilt angle. The turning control device 35 controls the speed of the induction motor 37 according to the turning chute rotation angular velocity command given from the turning chute rotation speed calculator 50, and thereby turns the turning chute 24 via the turning drive mechanism 39. . Inside the turning chute rotation speed calculator 50, the tilting control of the turning chute 24 is performed according to the input of the total charging amount W ₀ of the raw material and the total charging time T from the setting device 52. The turning control and the opening of the flow control gate 22 are controlled. Inside the turning chute rotation speed calculator 50, first,
The discharge rate W is calculated from the input total charge amount W ₀ of the raw material 1, the total charge time T, and the following equation. W = W ₀ / T (12) Further, the above equation (8), the total charging time T input from the setting device 52, and the turning chute rotation speed calculator 50 in advance.
The peripheral velocity V at the raw material drop point is obtained from the total length L ₀ of the drop point trajectory set inside. The angular velocity ω of the turning chute 24 is obtained as follows from the peripheral velocity V and the like at the raw material dropping point. The turning radius r of the raw material falling point is the turning radius r ₁ of the turning chute 24 at the tilt angle θ, and the raw material 1 from the turning chute 24 is
The fall distance of r is set to r ₂ , the length of the turning chute 24 is set to l ₁ ,
When the distance from the upper surface of the raw material in the blast furnace 10 to the swirl chute 24, which is obtained by the level meter 26, is l ₂ , it can be obtained as in the following equation. r ₁ = l ₁ sin θ (13) Therefore, the angular velocity ω at the raw material falling point can be calculated by the following formula. As described above, in the turning chute rotation speed calculator 50, the discharge speed W of the raw material 1 and the angular velocity ω of the turning chute 24 are
And ask. Further, the turning chute rotation speed calculator 50 controls the tilt angle θ and the turning angular speed ω of the turning chute so that the locus of the raw material 1 falling from the turning chute 24 becomes a locus as shown in FIG. Meanwhile, the raw material 1 is controlled to be discharged at the discharging speed W. Here, the coefficient P is used in the above equation (14), which is the discharge speed W of the raw material falling from the turning chute 24, the rotational angular velocity ω of the turning chute 24, and the charged raw material. Due to the difference in graininess of No. 1 and the like, for example, the distance l ₂ between the upper surface of the raw material in the blast furnace 10 and the swirling chute 24 and the swirling chute 24
This is because the above-mentioned fall distance r ₂ is different even if the tilt angle θ of the same is the same. 4 (A) and (B) show the raw material 1 from the turning chute 24.
FIG. 6 is a diagram showing a fall distance r ₂ of Comparing FIGS. 4A and 4B, the fall distance r _{2 of the} raw material 1 is greatly different. Generally, for example, as the rotational angular velocity ω of the turning chute 24 increases, the centrifugal force acting on the raw material 1 falling from the turning chute 24 increases, and the discharging speed W of the raw material 1 falling from the turning chute 24 increases. The speed of the raw material 1 falling from the turning chute 24 becomes higher, and again,
The more fluid the granularity of the raw material 1 falling from the turning chute 24 is, the higher the falling speed of the raw material 1 from the turning chute 24 is. In such a case, as compared with FIG. 4 (B). As shown in FIG. 4 (A), the fall distance r ₂ becomes large. For this reason, the coefficient P is stored in the turning chute rotation speed calculator 50 as a map for each factor that affects the fall distance r ₂ . It is possible to obtain the turning radius r of the raw material dropping point by a method as shown in FIG. 5, instead of the method of obtaining the turning radius r of the raw material dropping point by the above equations (13) to (15). FIG. 5 shows a turning radius r of a raw material falling point measured by a reflection type distance meter.
It is a diagram showing a measuring method of. In this figure, the reflection type distance meter 27 is a reflection type distance sensor.
The distance ls from the turning chute 24 to the falling raw material 1 is measured by 27a, and the distance to the falling raw material 1 as shown in FIG.
The relationship between ls and the turning radius r of the raw material drop point is stored as a map (when the distance ls ₀ , the turning radius r of the raw material drop point is stored.
Becomes zero). According to this map, the reflection-type distance meter 27 displays the turning radius r of the raw material drop point from the distance ls to the falling raw material.
Then, the turning radius r is output to the turning chute rotation speed calculator 50. By doing so, the turning radius r of the raw material falling point can be obtained more accurately. A microwave distance sensor, an ultrasonic distance sensor, or the like can be used as the reflection type distance sensor 27a.

【The invention's effect】

As described above, according to the present invention, the charging locus covering the entire blast furnace is accurately drawn without variation, and the raw material is stably charged at the corner charging position in the blast furnace, and particularly, the core of the blast furnace. Also in this case, there is an excellent effect that the charging amount can be accurately controlled and the charging time can be correctly controlled even if the charging amount is changed.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a raw material charging device for a blast furnace in which the present invention is implemented, and FIG. 2 is a raw material dropping point on the upper surface of the raw material in the blast furnace when the raw material is charged by changing a turning radius. A diagram showing an example of the locus, FIG. 3 (A) is a graph showing the relationship between the turning radius of the turning chute and the turning rotational speed, and FIG. 3 (B) is a turning radius of the turning chute and turning. The graph which shows the relationship between the peripheral velocity of the locus of the falling point in the blast furnace of the rotating raw material, FIGS. 4 (A) and 4 (B) are the line diagrams showing the fall distance of the raw material from the turning chute, Figure 5 shows the turning radius r of the raw material drop point measured by the reflection range finder.
FIG. 6 is a graph showing the relationship between the distance ls to the falling material measured by a reflection range finder and the turning radius r of the material dropping point. FIG. 7 shows the turning radius. FIG. 6 is a diagram showing a charging method when a conventional raw material charging method for a blast furnace using a variable swirling chute is used for a raw material charging device. 1 ... Raw material, 10 ... Blast furnace, 20 ... Upper hopper, 22 ... Flow control gate (FCG), 24 ... Swiveling chute, 26 ... Level meter, 26a ... Microwave length measuring sensor, 30 ... Tilt control device, 31 ... Servo motor , 32 ... tilt driving mechanism, 35 ... turn control system, 37 ... induction motor, 39 ... rotation drive mechanism, 50 ... pivoting chute rotation speed calculator, 52 ... setter, r ... turning radius of the raw material falling point, r ₁ ... turning radius of the turning chute in the tilt angle θ, r ₂ ... fall distance from the turning chute of the raw material, l ₁ ... length of the swivel chute, l ₂ ... of the turning chute from blast furnace raw material upper surface height, l s _... turning Distance from chute to raw material being dropped, θ ... Tilt angle of swivel chute, ω ... Rotational speed (angular velocity) of swivel chute, V ... Swirling peripheral velocity at raw material drop point, L ... Charging trajectory, L ₀ ... Drop point Total length of track, Ls… Starting point of charging, Le Charging end point, W 0 _... raw materials of SoSoIriryou, W ... discharge speed, Wd ... locus per unit length of the charging amount of raw materials fall point.

Claims (2)

[Claims] 1. A method for charging raw material discharged from a hopper into a blast furnace through a swirling chute whose swirling radius can be changed, and a predetermined total amount of charging in a method for charging raw material into a blast furnace. According to the above, the other is obtained from one of the charging speed and the charging time which is determined in advance, and the other is determined, and the turning peripheral speed of the turning chute is determined according to the charging time and the total length of the falling point trajectory from the turning chute. Obtaining, while turning the turning chute at the turning peripheral speed,
A method for charging a raw material into a blast furnace, which comprises charging the raw material into the blast furnace at the charging speed. 2. The material according to claim 1, wherein the position of the raw material falling from the turning chute is detected by a reflection range finder to obtain a turning radius at the raw material dropping point, and the raw material is referred to with reference to the turning radius at the raw material dropping point. A method for charging a raw material into a blast furnace, which is controlled so that a swirling peripheral speed at a dropping point becomes the swirling peripheral speed.