JPH0129849B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for charging raw material into a blast furnace using a bellless charging device for a blast furnace.

[Prior art and its problems]

A bellless charging device is known as one of the devices for charging raw materials into a blast furnace. As shown in the schematic diagram in FIG. 3, the bellless charging device charges coke and iron ore stored in a plurality of raw material storage tanks 3 into a bunker 2 provided at the top of a blast furnace 1. , is supplied alternately by the belt conveyor 4, the rotating chute 5 provided in the blast furnace 1 is continuously rotated, and the flow rate control valve 7 provided in the raw material discharge passage 6 of the bunker 2 is opened to release the material in the bunker 2. This device uniformly charges raw materials such as coke and iron ore into the blast furnace 1 using a rotating chute 5 that rotates continuously. According to this device, depending on the inclination angle of the swing chute 5 and the number of turns per certain time,
The charging distribution of raw materials in the radial direction of the blast furnace 1 can be controlled.

With this device, when charging the raw material into the blast furnace 1, the time required for discharging the raw material from the bunker 2 is kept constant in order to maintain a uniform distribution of raw material charging in the radial direction within the blast furnace 1. It is necessary.
The time for discharging raw materials from bunker 2 is as follows:
The flow rate control valve 7 provided in the raw material discharge passage 6 of the bunker 2 controls the flow rate of the rotating chute 5 while the raw material in the bunker 2 is being discharged.
It is controlled to keep the rotation speed constant.

However, since the discharge time of the raw material from the bunker 2 is influenced by many factors such as the particle size, moisture content, and surface properties of the raw material, it is difficult to keep the raw material discharge time constant using the flow rate control valve 7. FIG. 4 is a graph showing the discharge time of coke and iron ore from the bunker, which varies for each charging charge with respect to a predetermined target discharge time, and the fluctuation range of coke is particularly large.

FIG. 5 is an explanatory diagram showing the distribution state of coke and iron ore charged into the blast furnace 1 in the radial direction inside the furnace. As shown in the drawing, for example, if the time for discharging coke from the bunker, that is, the time for charging into the blast furnace 1, is shorter than a predetermined target time, the distribution will be as shown by dotted line b, compared to the target distribution shown by solid line a. The distribution becomes lower toward the core, and on the other hand, when the time is longer than the target time, the distribution becomes higher toward the core, as shown by the dotted line c, compared to the target distribution shown by the solid line a.

In this way, in the case of a bellless charging device, the time taken to discharge the raw material from the bunker varies depending on the particle size, moisture content, surface texture, etc. of the raw material.
The layer thickness ratio between coke and iron ore in the core of the blast furnace changes with each charging charge, which poses a problem that hinders smooth blast furnace operation.

[Purpose of the invention]

Therefore, an object of the present invention is to make the discharge time of the raw material from the bunker almost constant and to maintain a stable distribution state in the furnace when charging raw material into the blast furnace using a bellless type blast furnace raw material charging device. An object of the present invention is to provide a method for charging raw material into a blast furnace using a bellless type blast furnace raw material charging device.

[Summary of the invention]

The inventors of the present invention have conducted extensive research in order to solve the above-mentioned problems. As a result, the inventors found that it is necessary to predict the discharge characteristics of the raw material in order to determine the opening degree of the flow control valve provided in the raw material discharge passage of the bunker so as to keep the discharge time of the raw material from the bunker constant. and that there is a certain correlation between the discharge time of the raw material from the raw material storage tank and the discharge time of the raw material from the bunker based on the discharge characteristics of the raw material. did.

This invention has been made based on the above knowledge, and involves supplying the raw material in the raw material storage tank into a bunker installed at the top of the blast furnace, and passing the raw material in the raw material storage tank through the flow rate control valve installed at the raw material outlet of the bunker. , the raw material is discharged from the bunker, and the thus discharged raw material is distributed and charged into the blast furnace through a rotating chute provided at the upper part of the blast furnace. In the charging method, the actual discharge time of the raw material from the raw material storage tank;
The present invention is characterized in that the opening degree of the flow rate control valve is determined based on the target discharge time of the raw material from the bunker, and thus the discharge time of the raw material from the bunker is kept constant.

[Structure of the invention]

If the opening degree of the flow rate control valve 7 provided in the raw material discharge passage 6 of the bunker 2 and the opening degree of the discharge port of the raw material storage tank 3 for coke and iron ore are kept constant as shown in FIG. The raw material discharge time and the raw material discharge time from the raw material storage tank 3 are expressed by linear functions.

Therefore, the opening degree of the discharge port of the raw material storage tank is made constant, and the opening degree of the flow rate control valve is set to, for example, A, B, C, D, etc.
The relationship between the raw material discharge time from the bunker and the raw material discharge time from the raw material storage tank for each opening is changed to 6 stages E and F, and the relationship between the raw material discharge time from the bunker and the raw material storage tank is shown in Fig.
Become like Ro.

In FIG. 1A, the horizontal axis is the actual time for discharging raw materials from the raw material storage tank (however, the opening degree of the discharge port is constant), and the vertical axis is the time for discharging raw materials from the bunker. In FIG. 1B, the horizontal axis represents the actual discharge time of the raw material from the raw material storage tank, and the vertical axis represents the opening degree of the flow rate control valve. From FIGS. 1A and 1B, the opening degree of the flow rate control valve for making the discharge time of the raw material from the bunker constant can be determined based on the actual discharge time of the raw material from the raw material storage tank.

Therefore, based on the actual discharge time of the raw material from the raw material storage tank and based on the graphs in A and B of Figure 1 above, the opening degree of the flow control valve is determined to make the discharge time of the raw material from the bunker the target constant time. By determining this and controlling the flow rate control valve to the opening degree determined above, the time for discharging the raw material from the bunker can be maintained at the constant time described above.

FIG. 2 is a graph showing a comparison of the discharge time when coke is discharged from a bunker by determining the opening degree of the flow control valve according to the method of the present invention. As shown in FIG. 2, according to the method of the present invention, especially in the case of coke whose discharge time from the bunker fluctuates greatly, the fluctuation is reduced to less than one-fourth, and therefore, the coke discharge time in the blast furnace is reduced to less than one quarter. was able to be charged in a stable distribution state.

〔Effect of the invention〕

As described above, according to the present invention, when charging raw material into a blast furnace using a bellless type blast furnace raw material charging device, it is possible to By keeping the discharge time of the raw materials almost constant and charging the raw materials into the blast furnace in a stable distribution state, an excellent industrial effect is brought about in which the blast furnace can be smoothly operated.

[Brief explanation of drawings]

1A and 1B are graphs showing the raw material discharge time from the raw material storage tank and the raw material discharge time from the bunker in relation to the opening degree of the flow control valve of the bunker,
Fig. 2 is a graph showing the coke discharge time from the bunker for each charge according to the method of the present invention in comparison with the conventional method, Fig. 3 is a schematic explanatory diagram of a bellless type blast furnace raw material charging device, and Fig. 4 is a graph showing the conventional method. Graph showing material discharge time from bunker for each charge, 5th
The figure is an explanatory diagram showing the distribution state of raw materials charged into the blast furnace in the radial direction inside the furnace. In the drawings, 1... blast furnace, 2... bunker, 3... raw material storage tank, 4... belt conveyor, 5... rotating chute, 6... raw material discharge passage, 7... flow rate control valve.

Claims (1)

[Claims] 1. The raw material in the raw material storage tank is supplied into a bunker provided at the top of the blast furnace, and the raw material is discharged from the bunker through a flow rate control valve provided at the raw material outlet of the bunker. In a method of charging blast furnace raw material using a bellless type blast furnace raw material charging device, the raw material discharged in this manner is distributed and charged into the blast furnace through a rotating chute provided at the upper part of the blast furnace. The actual discharge time of raw materials from the storage tank,
Bell-less type blast furnace raw material charging, characterized in that the opening degree of the flow rate control valve is determined depending on the target discharge time of the raw material from the bunker, and thus the discharge time of the raw material from the bunker is kept constant. Method of charging blast furnace raw materials using equipment.