JP2005133170A - Method for discharging raw material for blast furnace and method for operating blast furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for discharging raw material for blast furnace and a method for operating the blast furnace with which the existing facility is used and the mixing ratio of ore and coke can be set to an optional value at a good accuracy so as to match to the operation state. <P>SOLUTION: This method comprises discharging the raw material for blast furnace using a charging conveyor 1 for conveying the raw material into a raw material charging device at the furnace top, an ore discharging hopper 2 for discharging the ore onto the charging conveyor 1 and a coke discharging hopper 3 for discharging the coke. When the ore and the coke are discharged onto the charging conveyor 1 from the ore discharging hopper 2 and the coke discharging hopper 3, these discharged ore and coke, are discharged so as to stack as the layer-state on the charging conveyor 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cutting method of a blast furnace raw material and a method of operating a blast furnace in hot metal production.

  A conventional blast furnace raw material cutting method in a blast furnace provided with a charging conveyor for charging raw materials such as ore and coke at the top of the furnace and a hopper for cutting ore and coke on the charging conveyer is The ore and coke were batch-cut on the incoming conveyor, and the ore and coke were alternately charged into the blast furnace. The purpose of this is to charge the ore and coke alternately into the blast furnace to ensure air permeability and the like in the furnace and to stabilize the operation.

  Further, when ore and coke are alternately charged into the blast furnace, a so-called mixed charging technique (for example, Japanese Patent Laid-Open No. Sho 62) that promotes reduction and melting of iron ore by mixing coke in the ore layer. No. -127413 (see Patent Document 1) is known. Iron ore heats up, reduces, softens, melts in the blast furnace, and eventually becomes hot metal and is cut out of the furnace, but when the amount of gas flowing through the layer decreases due to softening or shrinkage of the ore, the reduction of the iron ore stagnate. At the same time, the problem that melting and dropping are delayed becomes obvious. In the mixed charging technique in which coke is mixed with ore, coke dispersed and present in the ore layer prevents softening and shrinkage of the ore and improves air permeability in the layer.

Examples of the method of mixing the ore and coke include the following methods 1) to 3).
1) In the raw material yard, ore and coke are stacked in layers, for example, and the raw material is placed in the raw material hopper and handled as one brand (mixed ore coke).
2) A method in which, in a blast furnace having a plurality of raw material charging hoppers at the top of the furnace, ore and coke are put into separate hoppers and mixed when the raw materials are charged into the blast furnace furnace. For example, Japanese Patent Laid-Open No. 9-125112 (Patent Document 2) describes a method in which ore and coke are stored in separate hoppers at the top of the furnace and mixed and charged by cutting them out simultaneously.
3) A method of mixing coke as a brand of ore. For example, a method in which coke is put in a part of a plurality of raw material charging hoppers and used as a brand of ore.
Japanese Patent Laid-Open No. Sho 62-127413 JP-A-9-125112

However, the above methods 1) to 3) have the following problems. That means
In the method 1), in order to secure the amount of ore coke mixed raw material charged into the blast furnace, there are restrictions on the raw material hobber that multiple raw material layers must be used. However, the degree of freedom of operation for performing rationalization operation in consideration of the furnace condition is low.
The method 2) is a hand throw that can be applied only to a blast furnace having a plurality of raw material charging bunker at the top of the furnace, and cannot be carried out in other blast furnaces.
The method of mixing coke as a brand of ore in 3) can be used even when there is an operational need to greatly increase the amount of coke mixing due to restrictions on the number of raw material charging hoppers. It was not satisfactory and only a limited amount could be mixed. In addition, the number of ore hoppers is reduced by the amount of hopper allocated to coke, resulting in operational restrictions on ore blending.

  On the other hand, when the ore and coke are alternately charged into the blast furnace, the method is basically different from the method in which a small amount of coke is mixed in the ore layer. A method of charging inside is also conceivable. This is a problem that the present inventors have newly addressed from the viewpoint of improving the reactivity between ore and coke, but in this case as well, when mixing the ore and coke, the same problem as above Have

  The present invention has been made to solve the above-described problems, and is a blast furnace capable of accurately setting the mixing ratio of ore and coke to an arbitrary value in accordance with the operation status by using existing equipment. It aims at providing the cutting-out method of a raw material, and the operation method of a blast furnace.

The above problems are solved by the following invention.
[1] A charging conveyor for transporting raw materials to a raw material charging device at the furnace top, an ore cutting hopper for cutting ore on the charging conveyor, and a coke cutting hopper for cutting coke are provided. A method of cutting out blast furnace raw material in a blast furnace, wherein when the ore and coke are cut out from the ore cutting hopper and coke cutting hopper on the charging conveyor, the cut ore and coke are extracted from the charging conveyor. A method for cutting out a blast furnace raw material, characterized by being cut out so as to be laminated in layers.
[2] In the above [1], the ratio of the ore layer and the coke layer based on the ore or coke discharge speed cut out from the ore cutting hopper or the coke cutting hopper provided on the upstream side in the charging conveyor conveyance direction Of the blast furnace raw material characterized by controlling the discharge rate of coke or ore cut out from a coke cutting hopper or ore cutting hopper provided on the downstream side in the charging conveyor transport direction so that the ratio becomes a predetermined ratio Method.
[3] In the above [1] or [2], the adjustment of the ore discharge speed and the coke discharge speed is adjusted to the opening degree of each gate valve attached to the ore cutting hopper and the outlet side of the coke cutting hopper. The cutting method of the blast furnace raw material characterized by adjusting and adjusting.
[4] In any one of the above [1] to [3], feedforward control based on the deviation between the target weighing value and the actual weighing value to the ore cutting hopper and the coke cutting hopper, and / or the ore Featuring feedback control based on the deviation between the previous cutting time and the target cutting time for each of the cutting hopper and the coke cutting hopper, the opening degree of each of the ore cutting hopper and the coke cutting hopper is corrected. To cut out blast furnace raw material.
[5] A method of operating a blast furnace in which the ore and coke are mixed and charged into the blast furnace using the blast furnace raw material cutting method according to any one of [1] to [4].

  According to the present invention, there is provided a blast furnace raw material cutting method and a blast furnace operating method capable of accurately setting an ore and coke mixing ratio to an arbitrary value in accordance with an operation situation using an existing facility. Provided.

  Hereinafter, an example of the best mode for carrying out the present invention will be described.

  FIG. 1 is a schematic configuration diagram for explaining a blast furnace raw material cutting method according to the present invention. In FIG. 1, 1 is a charging conveyor for transporting raw materials to a raw material charging device at the furnace top, 2a and 2b are ore cutting hoppers (reserving hoppers) for cutting ore on the charging conveyor 1, 3a and 3b represents a coke cutting hopper (coke scale hopper) for cutting out coke on the charging conveyor 1 in the same manner.

  In FIG. 1, two ore cutting hoppers and coke cutting hoppers are installed in order to efficiently cut ore and coke, but the number of ore cutting hoppers and coke cutting hoppers is limited to two. It may be one, three or more, and may be appropriately changed depending on the facility scale or the operation status.

  Further, the ore cutting hoppers 2a and 2b and the coke cutting hoppers 3a and 3b have opening adjustments attached to the weighing machines 4a, 4b, 5a and 5b and the raw material cutting gates 6a, 6b, 7a and 7b, respectively. The raw material cutting gate opening meters 8a, 8b, 9a, 9b and the controller 10 for adjusting the opening of the raw material cutting gate opening meters 8a, 8b, 9a, 9b are provided. Based on the sensor data of the weighing machines 4a, 4b, 5a, 5b and the raw material cutting gate opening meters 8a, 8b, 9a, 9b, the operation data from the process control, etc., the controller 10 The opening degree of the total 8a, 8b, 9a, 9b is adjusted.

  FIG. 1 shows a configuration in which ore cutting hoppers 2a and 2b are installed on the upstream side in the conveying direction of the charging conveyor 1 and coke cutting hoppers 3a and 3b are installed on the downstream side in the conveying direction. The coke cutting hoppers 3a and 3b may be installed on the upstream side in the conveying direction of the conveyor 1, and the ore cutting hoppers 2a and 2b may be installed on the downstream side in the conveying direction. In the following description, the ore cutting hoppers 2a and 2b are installed on the upstream side in the charging conveyor transport direction, and the coke cutting hoppers 3a and 3b are installed on the downstream side in the transport direction of the ore cutting hoppers 2a and 2b. explain.

  On the charging conveyor 1, first, a predetermined amount of ore is cut out from one of the ore cutting hoppers 2a and 2b. Next, a predetermined amount of coke is cut out from one of the coke cutting hoppers 3a and 3b so as to be layered on the ore layer cut out on the charging conveyor 1. Here, the cut coke is laminated in layers so as to substantially coincide with the start and end of the ore layer already laminated on the charging conveyor 1.

  When ore and coke are stacked on the charging conveyor 1, based on the ore cutting speed cut out from the ore cutting hopper provided on the upstream side in the loading conveyor 1 conveyance direction, It is preferable to carry out by controlling the cutting speed of the coke cut out from the coke cutting hopper provided on the downstream side in the conveying direction of the charging conveyor 1 so that the ratio becomes a predetermined ratio.

  Moreover, in order to match the starting position in the conveyor flow direction of the lamination of the ore and coke, paying out from each hopper from the positional relationship between the ore cutting hoppers 2a and 2b and the coke cutting hoppers 3a and 3b and the speed of the conveyor. Timing is also calculated and adjusted to match.

  Here, the cutting speed of the ore cut out from the ore cutting hopper, and the cutting speed of the coke cut out from the coke cutting hopper are the opening degree of the raw material cutting gate opening meter in the ore cutting hopper, and the coke cutting hopper. Can be performed by adjusting the opening of the raw material cutting gate opening meter. In addition, the opening degree of the raw material cutting gate opening meter in the ore cutting hopper is maintained at the same opening degree while the ore in the ore cutting hopper is cut out so that the ore layer has a uniform layer thickness. Is cut out on the charging conveyor 1. Similarly, the opening degree of the raw material cutting gate opening meter in the coke cutting hopper is maintained at the same opening degree while the coke in the coke cutting hopper is cut out, so that the coke layer has a uniform layer thickness. It is cut out on the ore layer so that it becomes.

  Thereby, it becomes possible to laminate ore and coke on the charging conveyor 1 at an arbitrary ratio, and it is possible to accurately perform the mixing ratio of the ore and coke at an arbitrary ratio.

  In the present invention, the feedback control based on the deviation between the target weighing value and the actual weighing value to the ore cutting hopper and the coke cutting hopper, and / or the previous cutting time of each of the ore cutting hopper and the coke cutting hopper It is preferable to perform opening correction of the raw material cutting gate opening meter of each of the ore cutting hopper and the coke cutting hopper by feedforward control based on the deviation between the target cutting time and the target cutting time. As a result, the ore and coke can be cut out with higher accuracy.

  FIG. 2 is a flowchart showing an example of an opening correction method for the raw material cutting gate opening meter of each of the ore cutting hopper and the coke cutting hopper performed in the controller 10. Hereinafter, an example of the opening correction method will be described with reference to the flowchart shown in FIG.

The opening degree correction is performed according to the following procedure for each of the ore cutting hopper and the coke cutting hopper. Here, on the charging conveyor 1, in order to make each start end and termination | terminus of an ore layer and a coke layer correspond, the target cut-out time in an ore cut-out hopper and a coke cut-out hopper is set to the same set value.
1) The cutting speed Vt is calculated by the following equation (1) from the planned weighing value Wt [T] of the next weighed ore given from the weighing schedule determined in advance and the target cutting time Tt determined from the planned yield. calculate.
Vt = Wt / Tt (1)
2) The upper and lower limits of the cutout speed Vt calculated in 1) above are checked, and if they are out of the range, the upper and lower limits are replaced and the corrected cutout speed Vt ′ is determined according to the following conditions.
When Vt ≧ Vmax, Vt ′ = Vmax
When Vmax>Vt> Vmin, Vt '= Vt
When Vt ≦ Vmin, Vt ′ = Vmin
Vmax: maximum cutting speed, and Vmin: minimum cutting speed.
3) The correction target cut-out time Tt ′ is recalculated from the cut-out speed Vt ′ determined in the above 2) by the following equation (2).
Tt '= Wt / Vt' (2)
4) The optimum gate opening for the corrected target cutout time Tt ′ calculated by the above equation (2) is calculated by the function of the gate opening θ expressed by the following equation (3) using the cutout time T as a parameter. To do.
θ = f (T) (3)
This is the target gate opening θt. The parameter of the function used in the calculation is approximated by the least square method or the like based on the relationship between the cut-out time T and the gate opening θ obtained by the operation accumulated so far in the process controller, and the controller 10 Send.
The gate opening is calculated for each of the ore cutting hopper and the coke cutting hopper.
5) The upper and lower limits of the target gate opening θt calculated in the above 4) are checked, and the corrected target gate opening θt ′ is determined by replacing the upper and lower limits with the upper and lower limits if they are out of the range according to the following conditions.
Here, θmax is the gate opening maximum value [%], and θmin is the gate opening minimum value.
If θt ≧ θmax, θt '= θmax
If θmax>θt> θmin, θt '= θt
If θt ≦ θmin, θt '= θmin
The corrected target gate opening degree θt ′ may be input by manually setting the opening degree.
6) When feedforward correction of the corrected target gate opening θt ′ determined in 5) above is performed, the weighing value is calculated based on the deviation ΔW between the actual weighing value W and the target weighing value Wt weighed by the hopper to be cut out. The corrected target gate opening degree θt ′ is corrected according to the following equation (4) using the function as a parameter.
θt '= θt' + Δθ _FF (4)
Here, Δθ _FF = k _FF × ΔW, k _FF : a constant set value (usually a negative value).
7) With respect to the corrected target gate opening θt ′ after the feedforward correction according to 6) above or the corrected target gate opening θt ′ determined in 5) above, When feedback correction is performed, the following processing is performed based on the deviation ΔT between the previous cutout time T and the corrected target cutout time Tt ′ to correct the corrected target gate opening θt ′.
a) The actual cutting time T is calculated from the actual gate opening θ and the actual weighing value W.
b) The target cutout time Tt ′ at that time and the cutout time deviation ΔT of the actual cutout time T obtained in a) are obtained.
c) Based on the above deviation, the corrected target gate opening degree θt ′ is feedback-corrected based on the following equation (5) by a function using the cut-out time deviation ΔT as a parameter.
θt '= θt' + Δθ _FB (5)
Here, Δθ _FB = k _FB × ΔT, k _FB : constant setting value (usually a negative value).

  As described above, in the present embodiment, the ore cutting hoppers 2a and 2b are installed on the upstream side in the conveying direction of the charging conveyor 1, and the coke cutting hoppers 3a and 3b are installed on the downstream side in the conveying direction of the ore cutting hoppers 2a and 2b. In the case where the coke cutting hoppers 3a, 3b are installed on the upstream side in the conveying direction of the charging conveyor 1 and the ore cutting hoppers 2a, 2b are installed on the downstream side in the conveying direction of the coke cutting hoppers 3a, 3b, In the above description, the present invention can be similarly applied by replacing the ore cutting hopper and the coke cutting hopper.

It is a schematic block diagram for demonstrating the cutting method of the blast furnace raw material which concerns on this invention. It is a flowchart which shows an example of the opening correction method with respect to the raw material cutting gate opening degree meter of each of the ore cutting hopper and the coke cutting hopper performed in the controller based on this invention.

Explanation of symbols

1 Charging conveyor 2 Ore cutting hopper (Reserving hopper)
3 Coke cutting hopper (coke scale hopper)
4,5 Weighing device 6,7 Raw material cutting gate 8,9 Raw material cutting gate opening meter 10 Controller

Claims (5)

In a blast furnace equipped with a charging conveyor for transporting raw materials to a raw material charging device at the furnace top, an ore cutting hopper for cutting ore on the charging conveyor, and a coke cutting hopper for cutting coke A method for cutting out blast furnace raw material,
When ore and coke are cut out from the ore cutting hopper and coke cutting hopper on the charging conveyor, the cut ore and coke are cut out so as to be layered on the charging conveyor. A method for cutting out blast furnace raw material.   Based on the ore or coke discharge speed cut out from the ore cutting hopper or coke cutting hopper provided on the upstream side of the charging conveyor conveyance direction, the ratio of the ore layer and the coke layer becomes a predetermined ratio, The blast furnace raw material cutting method according to claim 1, wherein a discharge speed of the coke or ore cut out from a coke cutting hopper or an ore cutting hopper provided on the downstream side in the charging conveyor conveyance direction is controlled.   2. The adjustment of the ore discharge rate and the coke discharge rate is performed by adjusting the opening degree of each gate valve attached to the outlet side of the ore cutting hopper and the coke cutting hopper. Or the cutting method of the blast furnace raw material of Claim 2.   Feedforward control based on the deviation between the target weighing value and the actual weighing value for the ore cutting hopper and the coke cutting hopper, and / or the previous cutting time and target of each of the ore cutting hopper and the coke cutting hopper The blast furnace raw material according to any one of claims 1 to 3, wherein the opening correction of each of the ore cutting hopper and the coke cutting hopper is performed by feedback control based on a deviation from the cutting time. How to cut out Using the blast furnace raw material cutting method according to any one of claims 1 to 4,
Blast furnace operation method in which ore and coke are mixed and charged in the blast furnace.

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