JPS62290809A - Raw material charging method for blast furnace - Google Patents

Abstract

PURPOSE:To maintain stable center gas flow in a blast furnace by charging most of necessary cokes on the whole cross section of the blast furnace as layer and separately charging the remained cokes at the center part of the furnace. CONSTITUTION:The most of necessary cokes are charged as changing gradually the discharging part at lower end part of a rotating chute 11 from inclined angle theta1 in the range from the middle point between the furnace center and the furnace wall 12 to the furnace wall 12, to form the coke layer 14 on ore layer 13. Then, as the coke in the coke layer 14 is gradually flowed from the furnace wall side toward the furnace center part, the layer thickness is almost uniformized. Next, the rotating chute 11 is positioned at the furnace center line, and the remaining cokes are charged to form slightly elevated coke boundary 14a at the center part on the coke layer 14. Further, the ore layer 13 is formed on this, to obstruct flowing of the ore further into the center part by the center part coke boundary 14a. In this way, the coke layer 14 and the ore layer 13 are piled alternately and in the furnace center part, the columnar coke boundary composing of coke only is formed.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for charging raw materials into a blast furnace using a bellless charging device.

(Prior Art) Conventionally, in a blast furnace that uses a bellless charging device to alternately charge coke and ore into the furnace, as shown in FIGS. 5 to 7, the tilting angle of the rotating chute 1 is By changing θ during charging of coke or ore, charging raw materials to adjust the layer thickness of ore and coke in the radial direction of the cross section of the furnace, and controlling the layer thickness ratio, The gas flow distribution is controlled, thereby maintaining a stable central gas flow to reduce fuel costs and maintain equipment.

However, as shown in FIG. 6, there is a method in which coke necessary for forming each coke layer is charged at once from the furnace wall 2 side to the furnace center while changing the tilting angle θ of the rotating chute 1. In this case, since the particle size of coke varies and the coke supply speed from the fixed hopper 3 at the top of the furnace to the rotating chute 1 in Fig. 5 changes, a fixed amount of coke is loaded into the center of the furnace, which is the final charging section. As a result, it becomes difficult to maintain the core gas flow in the furnace, which is necessary to save fuel costs and maintain good equipment maintenance. In addition, charging of coke is carried out at the furnace wall 2.
Since the coke turns from the side and forms a relatively long spiral line toward the center of the furnace, the thickness of the coke layer in the circumferential direction of the cross section of the furnace tends to be uneven, and as a result, the operation of the blast furnace is adversely affected.

On the other hand, as shown in FIG. 7, the furnace walls 2
In the method of charging coke necessary for forming each coke layer into the furnace at once while changing the tilting angle θ of the rotating chute 1 toward the side, an area containing only coke must be secured in the center of the furnace. is possible, but the controllability is extremely poor when adding a small amount of coke in a fixed amount, making it difficult to maintain a stable central gas flow. In addition, since the coke charging takes the form of a relatively long spiral line, which is the same as in the conventional example shown in Figure 6, there is a problem with blast furnace operation due to uneven coke layer thickness in the circumferential direction of the cross section of the furnace. It is not possible to avoid negative effects.

In this way, in order to maintain a stable central gas flow in the furnace, it is important to create a region formed only by a coke layer in the center of the blast furnace. The reality is that this has not been achieved. In particular, operating conditions that suppress the formation of a coke region in the center of the furnace;
For example, in blast furnaces that use berent ore, the ore flows into the center of the furnace rapidly and the coke area in the center of the furnace decreases significantly, making it extremely difficult to maintain a stable central gas flow. There are problems.

[Purpose of the invention]

The present invention has been made in consideration of the above-mentioned conventional problems, and it is possible to maintain a stable central gas flow in the furnace regardless of the operating conditions, such as when operating a pellet-rich blended raw material, thereby reducing fuel costs. The purpose of the present invention is to provide a method for charging raw materials into a blast furnace that enables reduction of the amount of waste and good equipment maintenance.

[Structure of the invention]

A blast furnace raw material charging method according to the present invention is a blast furnace raw material charging method in which coke and ore are alternately charged to form a coke layer and an ore layer alternately in the furnace. After most of the charged coke necessary to form the layer is charged in layers across the entire surface of the furnace, the remaining coke weighed to a certain extent is separately charged onto the layered coke in the center of the furnace.
The present invention is characterized in that by forming the above coke layer, a central coke region consisting only of coke is formed in the center of the furnace.

〔Example〕

An embodiment of the present invention will be described below based on FIGS. 1 to 4.

(1) First, as shown in FIG. 1, the lower end discharge portion of the rotating chute 11 for charging raw materials is rotated.

The tilting angle θ1 of the rotating chute 11 is between the furnace center and the furnace wall 12.
The rotation chute 11 rotates in the furnace while gradually changing its tilt angle θ1 within the above setting range, and each coke Most of the charged coke required to form the layer is charged into the furnace from the lower end discharge part of the rotating chute 11 so as to form a layer over the entire surface of the furnace. still,
The change range of the tilting angle θ of the turning shoe 1-11 is as follows:
It is set not in the entire range from the furnace center to the furnace wall 12, but in the range from the midpoint between the furnace center and the furnace wall 12 to the furnace wall 12, and the above-mentioned tilt angle θ is gradually changed within that range. It is something that will be done.

By the above-mentioned coke charging, a coke layer 14 consisting of most of the required coke charge is formed on the ore layer 13 whose upper surface is shaped like a pot. Since the coke gradually flows from the furnace wall side toward the furnace center, the coke layer 14 is formed to have a substantially uniform layer thickness in the radial direction of the furnace cross section. Further, the tilting angle θ1 of the rotating chute 11 is changed within a smaller range than in the conventional example, and as a result, coke is charged in a relatively short spiral line, so that The uniformity of the layer thickness is also ensured.

(2) After completing the above steps, as shown in Fig. 2, the swing chute 11 is rotated so that the tilting angle of the swing chute 11 is 0, that is, the center line of the swing chute 11 is aligned with the center line inside the furnace. A chute 11 is set to discharge a certain amount of coke, which is the remainder of most of the previously charged coke, onto the layered coke at the center of the furnace. As a result, a slightly raised center coke region 14a is formed at the center of the coke layer 14 formed in the previous step.

(3) After that, as shown in FIG. 3, the lower end discharge portion of the rotating chute 11 is rotated, and from the discharge portion of the rotating chute 11 directed toward the furnace wall 12 side of the coke layer 14,
All the ores necessary to form the ore layer 13 on the upper surface of the coke layer 14 formed in the process shown in FIG. 1 are discharged at once. In this case, the center coke region 14a formed in the process shown in FIG. 2 is not completely filled with the ore, and the center coke region 14a prevents the ore from flowing into the furnace center. .

(4) By sequentially repeating each of the steps shown above, a deposited layer in which ore layers 13 and coke layers 14 are alternately stacked is formed as shown in FIG. In the center of the furnace, a columnar coke region made only of coke is formed by stacking the central coke region 14a. Since the central coke region 14a is formed of a small amount of coke weighed at a constant rate, the cross-sectional area of the columnar coke region is approximately constant, thereby making it possible to maintain a stable central gas flow.

〔Effect of the invention〕

As described above, the method for charging raw materials in a blast furnace according to the present invention is a method for charging raw materials in a blast furnace in which coke and ore are charged alternately to form alternately laminated layers of coke and ore in the furnace. Most of the charged coke required to form each coke layer is charged in layers across the entire surface of the furnace, and then the remaining coke weighed to a certain extent is separately charged onto the layered coke in the center of the furnace. The above-mentioned coke layer is then formed.

Therefore, a region consisting only of coke is formed in the center of the furnace, which makes it possible to maintain a stable core gas flow, stabilize the blast furnace condition, and improve equipment maintenance.
It also becomes possible to reduce fuel costs. Furthermore, even in operations with a large amount of pellet ore, in which the coke area at the center of the furnace tends to be extremely reduced due to the flow of ore into the center of the furnace during raw material charging, the above effects can be achieved with the same certainty. There are advantages.

[Brief explanation of the drawing]

1 to 4 are process explanatory diagrams showing one embodiment of the present invention, FIG. 5 is a schematic diagram showing an example of a bellless charging device, and FIG. 6 is a schematic diagram showing an example of a bellless charging device.
FIG. 7 and FIG. 7 are explanatory diagrams each showing a conventional charging method. 11 is a rotating chute, 13 is an ore layer, 14 is a coke layer, and 1.42 is a central coke region. Patent applicant: Kobe Steel, Ltd. Figure 3
Figure 4 No. 6 Figure 7

Claims (1)

[Claims] In a blast furnace raw material charging method in which coke and ore are charged alternately to form alternately stacked coke layers and ore layers in the furnace, the amount of charged coke required to form each coke layer is The coke layer is formed by charging most of the coke in a layer across the entire surface of the furnace, and then separately charging the remaining coke weighed to a certain extent onto the layered coke in the center of the furnace. How to charge raw materials into a blast furnace.