JP2006219729A - Method for controlling distribution of raw materials charged into blast furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of controlling the distribution of raw materials to be charged into a blast furnace highly precisely without increasing the number of charging batches. <P>SOLUTION: The raw materials are charged into the blast furnace by using a raw material charging apparatus composed of a lower part bunker 1 for temporarily storing the charging raw materials for blast furnace, an FCG (a gate for controlling a flow rate) 2 at the time of charging the raw materials into the blast furnace, and a distribution chute 3 for dropping down the raw materials into the furnace while being rotated and inclined. In this case, when variation of the inclining angle in the distribution chute is a predetermined value or above during the charging of the raw materials stored in the bunker into the blast furnace through the distribution chute, the gate is made into a close state. In this operation, it is desirable to use a controller 6 for controlling the distributing chute and the gate, thereby controlling the distribution of the charged materials more highly precisely. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for controlling the distribution of raw materials charged into a blast furnace.

  In a blast furnace having a bell-less device, the distribution control of raw materials such as coke and ore charged into the blast furnace is performed by continuously adjusting the inclination angle (tilt angle) of the distribution chute while rotating the distribution chute. It is done. The charging of ore or coke into the blast furnace is carried out in units called batches. One batch of blast furnace charging raw material is temporarily stored in a bunker and charged into the blast furnace using a distribution chute. Operate by forming a multi-layered structure of coke.

Since the distribution state of the raw material charged in the blast furnace greatly affects the operation, distribution control of the charged raw material is performed so that the raw material forms a predetermined distribution. For example, a raw material charging method in a bell-less type blast furnace in which an approximate expression is created based on results and the opening degree of the FCG is adjusted (see, for example, Patent Document 1 and Patent Document 2), or a raw material is supplied at a predetermined charging speed. A raw material charging control method (see, for example, Patent Document 3) that finely adjusts the opening of the FCG so that the flow rate is constant for charging is known.
JP-A-2-254111, JP-A-4-198412 Japanese Patent Laid-Open No. 5-86410

  However, when charge distribution control is performed by the methods of Patent Documents 1 to 3, there is a problem that the charge distribution is disturbed in a part of the blast furnace. A concave portion is formed in the raw material charged in the blast furnace. In this case, even if control is performed such as changing the number of times of distribution depending on the tilt angle of the distribution chute, the charged material is charged uniformly. It is difficult.

  In addition, it is possible to reduce the amount of raw material charged in one batch and to charge a small amount in a small range to solve the above problem, but such a method increases the number of batches. For example, in the case of a vertical two-stage bell-less blast furnace, it takes extra time to equalize the lower bunker to charge the raw material, or to discharge the pressure to receive the next raw material in the lower bunker after charging. In order to hinder the charging capacity, it is not possible to satisfy the operational needs to increase the charging amount by one batch and reduce the number of batches as much as possible.

  Therefore, the object of the present invention is to solve such problems of the prior art and to distribute the blast furnace charging raw material capable of controlling the distribution of the raw material charged into the blast furnace with high accuracy without increasing the number of charging batches. It is to provide a control method.

The features of the present invention for solving such problems are as follows.
(1) a bunker that temporarily stores the raw material charged in the blast furnace, a gate that adjusts the flow rate when charging the raw material into the furnace, a distribution chute that rotates and tilts and drops the raw material into the furnace In the method of controlling the distribution of the raw material charged into the blast furnace using the raw material charging device, the tilt angle of the distribution chute when the raw material stored in the bunker is charged into the blast furnace by the distribution chute The blast furnace charging material distribution control method is characterized in that the gate is closed when the amount of change is greater than or equal to a predetermined value.
(2) A method for operating a blast furnace, characterized in that the blast furnace operation is performed by controlling the material distribution in the blast furnace using the distribution control method for blast furnace charging raw materials described in (1).

  According to the present invention, it is possible to control the charge distribution in the blast furnace with high accuracy while maintaining a high degree of freedom without hindering the furnace top charging ability. Therefore, it becomes possible to operate the blast furnace with a higher degree of freedom and further rationalization is possible.

  The present inventors examined the problem of charge distribution control, and paid attention to the fact that the distribution of the charge deteriorated when the tilt angle of the distribution chute was changed greatly, and charged the raw material into the furnace. The present invention was completed by finding that the distribution of the charged raw material can be controlled to a high degree by adjusting the opening of the gate for adjusting the flow rate.

  In the conventional blast furnace charge control, the charge flow rate adjustment gate (hereinafter referred to as FCG) was always open during one charge batch. That is, the raw material is charged while the FCG is open.

  However, if the tilt angle of the distribution chute is significantly changed during the raw material charging in one batch while the FCG is kept open, the distribution of the charged material in the blast furnace is disturbed. The distribution situation of this charge is demonstrated using FIG. 3, FIG. FIG. 3 shows the distribution of charges when the tilt angle of the distribution chute is changed little by little. (A) shows the inside of the blast furnace 4 when viewed from above, and (b) shows the inside of the blast furnace 4 when viewed from the side. It is explanatory drawing in the case. As shown in FIG. 3 (a), when charging the raw material from the upper distribution start point 11 along the arrow, the blast furnace from the furnace center 12 side to the iron shell 13 side as shown in FIG. 3 (b). The raw material 14 can be charged almost uniformly. On the other hand, for example, when an operation is performed in which a raw material is not charged at a specific position in the radial direction, the tilt angle of the distribution chute is greatly changed during the raw material charging in one batch. The case is shown in FIG. FIG. 4A is an explanatory view when the inside of the blast furnace 4 is viewed from above, and FIG. 4B is an explanatory view when the inside of the blast furnace 4 is viewed from the side (cross-sectional view at the position of the dashed line in FIG. is there. As shown in FIG. 4A, when the raw material is charged along the arrow from the upper distribution start point 11, the distribution of the charged material is disturbed at the portion surrounded by the dotted line. As a result, as shown in FIG. 4 (b), the blast furnace raw material 14 is originally intended to have a uniform charging state in which the raw material is not charged into the arrow portion, but the raw material is partially charged. As a result, a concave portion as indicated by a solid line is formed in the arrow portion of the blast furnace raw material 14, and a uniform raw material layer thickness cannot be formed. In this case, even if control for changing the number of times of distribution is performed according to the tilt angle, it is difficult to obtain a charge distribution state as shown in FIG.

  As described above, if the tilt angle is changed significantly with the FCG opened, the charge distribution in the furnace deteriorates. Therefore, in the present invention, a method for controlling the distribution of the raw material by closing the FCG when the tilt angle is significantly changed was studied. That is, a raw material comprising a bunker for temporarily storing the raw material charged in the blast furnace, a gate for adjusting the flow rate when the raw material is charged into the furnace, and a distribution chute that rotates and tilts to drop the raw material into the furnace In the method of controlling the distribution of the raw material charged into the blast furnace using the charging device, the gate is closed when the raw material stored in the bunker is charged into the blast furnace by the distribution chute. A blast furnace charging material distribution control method characterized in that the gate is closed when the amount of change in the tilt angle of the chute exceeds a predetermined value.

  Furthermore, it is desirable to control the turning action of the distribution chute, the tilt angle of the distribution chute, and the opening of the FCG using a control device.

  By performing control to close the FCG during one batch of raw material charging, it is possible to uniformly charge the raw materials and control the charge distribution with high accuracy while having a high degree of freedom in one charging batch. Is possible.

  The amount of change in the tilt angle of the distribution chute when the gate is closed is the amount of change in the tilt angle (for example, 5 degrees) that is considered to be conspicuous in the distribution of the charge in consideration of operational experience. 10 degrees) may be set as appropriate according to the operating conditions, and the gate is closed when the amount of change in the tilt angle of the distribution chute is equal to or greater than the set value.

  Note that parameter values corresponding to angles such as the number of notches may be used without directly setting the tilt angle as a control variable.

  By using the above-mentioned raw material distribution control method in the raw material charging process in blast furnace operation, it is possible to control the distribution of the charged material in the blast furnace with high accuracy, optimize the operating conditions, and operate the blast furnace. Can be further rationalized.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  In the raw material charging apparatus used in this embodiment, two bunkers, an upper bunker and a lower bunker, are connected by a port, the raw material in the upper bunker is transferred to the lower bunker through the port, and the raw material is transferred from the lower bunker. This is a vertical two-stage bellless charging device that is charged into the furnace from the top of the blast furnace. The distribution chute installed in the lower part of the lower bunker is swung to change the inclination angle of the distribution chute and charge the raw material into the blast furnace. A schematic diagram of the blast furnace top is shown in FIG. An FCG 2 that is a gate for adjusting the flow rate of the charged raw material is installed in the lower part of the lower bunker 1, and the raw material is charged into the blast furnace 4 by the distribution chute 3 that tilts and turns. Reference numeral 5 denotes a lower seal valve. Reference numeral 6 denotes a distribution chute and FCG controller.

  Using the above raw material charging apparatus, the raw material is charged in the following procedure.

  (A) The total number of swirling of the distribution chute (time for charging the raw material charged in the furnace) and the distribution chute tilt angle corresponding to each number of swirling are set.

  Based on the settings of (b) and (a), the number of turns at which the distribution of the charged material in which the inclination angle of the distribution chute greatly changes is calculated.

  (C) The FCG opening is calculated from the furnace interior mass and the total number of turns of the distribution chute.

  (D) Move to the set tilt angle of the first turn of the distribution chute. It is also possible to move after completion of the previous furnace interior entry.

  (E) Rotate the distribution chute.

  (F) When the distribution chute has reached a predetermined distribution start point, the FCG is opened to the set opening and the furnace interior is started.

  According to the relationship between the number of turns and the tilt angle set in (g) and (a), the distribution chute is tilted.

  (H) When the number of turns calculated in (b) above is reached while entering the furnace interior, the FCG is temporarily closed while tilting the distribution chute.

  (I) When the distribution chute has been moved to the set value and has reached the distribution start point, the FCG is opened to the set opening and the furnace interior is resumed. At this time, during the distribution chute movement (while the FGC is closed), the actual number of turns is not counted.

  (J) Repeat (g) to (i) until charging is completed (the raw material is no longer in the lower bunker).

  The above operation is desirably performed using a control device (controller) that controls the distribution chute and the FCG. From the controller 6, a turning command A is given to the distribution chute 3, a turning position result B of the distribution chute 3 is received, a tilt command C is given to the distribution chute 3, a tilt position result D is received from the distribution chute 3, and based on these, the FCG It is possible to control the distribution of the charge with higher accuracy by giving the FCG opening / closing command E to the vehicle and receiving the actual FCG opening degree F from the FCG.

  FIG. 2 shows the relationship between the turning angle of the distribution chute, the FCG opening, the tilting angle of the distribution chute, and the charging amount of the raw material when charging the raw material as described above. The charging amount is indicated by the mass of the raw material remaining in the lower bunker. As shown in FIG. 2, the FCG is closed when the tilt angle of the distribution chute is greatly changed.

  Coke and ore were charged into the blast furnace using a vertical two-stage bell-less charging device. The total number of turns of the distribution chute and the distribution chute tilt angle corresponding to each number of turns were set as shown in Table 1. The numerical values shown in Table 1 are the number of notches corresponding to each number of turns, and correspond to the distribution chute tilt angle. In this embodiment, one notch unit corresponds to about 3 degrees of the distribution chute tilt angle, and the number of notches is used as a parameter value corresponding to the tilt angle.

  Based on the settings in Table 1, calculate the number of revolutions that cause a disturbance in the charge distribution as shown in Fig. 4, and calculate the FCG from the mass of the raw material charged into the furnace and the total number of revolutions of the distribution chute. The degree was calculated.

  The distribution chute was moved to the set tilt angle of the first turn, and the distribution chute was turned. When the distribution chute came to a predetermined distribution start point, the FCG was opened to the set opening and the furnace interior was started, and the distribution chute was tilted according to the setting of the number of revolutions and tilt angle in Table 1.

  The FCG was temporarily closed while tilting the distribution chute when the number of revolutions causing disturbance of the charge distribution was reached while entering the furnace interior.

  FIG. 2 shows the state from the seventh turn when the coke is charged according to Table 1. The condition for closing the FCG is that the change amount of the notch number is 5 or more (the tilt angle is about 12). Greater than degree). When the tilt angle changes from 9 to 25 in terms of the number of notches, the FCG is set closed when the 10th turn changes to the 11th turn.

  When the distribution chute was moved to the set value (tilt angle equivalent to 25 notches) and reached the distribution start point, the FCG was opened to the set opening and the furnace interior was resumed. At this time, during the distribution chute movement (FGC closed), the actual number of turns was not counted, and the resumption of charging was made the condition of the 11th turn. In this way, the distribution chute is tilted according to the setting of the number of turns and the tilt angle in Table 1 until the raw material in the lower bunker runs out. The FCG is temporarily closed while the distribution chute is moved to the set value, and when the distribution start point is reached, the operation of opening the FCG to the set opening degree and restarting the furnace interior is repeated to install one batch of coke. Completed. The charging of one batch of ore was performed in the same manner, and charging of one charge was completed.

  When the charging state after charging the raw material was examined, it was found that no concave portion was formed and the raw material was uniformly distributed.

  And, by using this raw material distribution control method in the raw material charging process in the operation of the blast furnace, the degree of freedom of the operating conditions can be increased, and as a result, further rationalization of the blast furnace operation can be realized. Became possible.

Schematic of a blast furnace top part. The graph which shows the relationship between the turning angle | corner of a distribution chute, the FCG opening degree, the inclination angle of a distribution chute, and the charging amount of a raw material. Explanatory drawing of the distribution status of the charge (when the tilt angle of the distribution chute is changed little by little). (A) When viewing the blast furnace from above, (b) When viewing the blast furnace from the side Explanatory drawing of the distribution situation of a charge (when changing the tilting angle of the distribution chute). (A) When viewing the blast furnace from above, (b) When viewing the blast furnace from the side

Explanation of symbols

1 Lower bunker 2 FCG
3 Distributing Chute 4 Blast Furnace 5 Lower Seal Valve 6 Controller 11 Distribution Start Point 12 Furnace Center 13 Iron Skin 14 Blast Furnace Raw Material A Turning Command B Turning Position Result C Tilt Command D Tilt Position Result E FCG Open / Close Command F FCG Opening Result

Claims (2)

  A raw material device comprising a bunker for temporarily storing the raw material charged in the blast furnace, a gate for adjusting a flow rate when the raw material is charged into the furnace, and a distribution chute that rotates and tilts to drop the raw material into the furnace. In the method of controlling the distribution of the raw material charged into the blast furnace using the charging device, when the raw material stored in the bunker is charged into the blast furnace by the distribution chute, the amount of change in the tilt angle of the distribution chute is A blast furnace charging raw material distribution control method, wherein the gate is closed when a predetermined value or more is reached.   A method for operating a blast furnace, wherein the distribution of raw materials in the blast furnace is controlled using the distribution control method for raw materials charged in a blast furnace according to claim 1.

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