JPS6021308A - Method for charging raw material to blast furnace - Google Patents

Abstract

PURPOSE:To maintain always the specified relative charge distribution in the radial direction even if an abrupt change arises in a stock level by measuring momentarily the stock level during charging of a raw material into a blast furnace and controlling the falling position of the raw material according to the change thereof. CONSTITUTION:If there is a slip or drop in the charge in the midway of charging, a stock level L falls down to L'. The titling angle theta of a charge distributor 3 in this stage is so set as to fall the charge into a target position P with the level L as a reference and when the stock line falls to L', the material is charged to the position P' and the charge distribution is disturbed. The relation between the angle theta and the position where the raw material falls is thereupon preliminarily determined and if the level change DELTAL is small, the angle change DELTAtheta corresponding to the DELTAL approximates linearly thereto. A coefft. K is predetermined by the equation I . When a sounding device 1 which measures momentarily the level L detects the change (l) in the level L, an arithmetic device 2 calculates the equation II and applies a command for correcting the set angle of the chute 3 to a control device 4 by which said set angle is corrected by the K.l deg.. The charge is thus dropped to the target position.

Description

Detailed Description of the Invention (Technical Field of the Invention) The present invention relates to a method for charging raw materials into a blast furnace, and more particularly, even if the stock level suddenly changes due to slips or drops during charging, (Technical background of the invention and its problems) In a blast furnace, the distribution state of the charge is determined by the gas flow t' in the furnace. It is generally known that it has a great influence on the formation of L or cohesive zone.

Therefore, various methods have been proposed to control the distribution of the charge.

For example, in the case of a bell-type charging device, a movable armor is provided to control the distribution of the charge in the radial direction of the furnace by causing the charge falling from the bell to hit the armor. In the case of a bellless charging device, the distribution in the radial direction of the furnace is controlled by changing the inclination angle of the rotating seat.

However, the conventional charge distribution control
This is carried out according to a preset distribution schedule for the material before it is charged, so slips and slips may occur during charging.
Even if a drop or the like occurs and the stock level suddenly changes, the falling position of the raw material is not adjusted accordingly. Therefore, when stock level changes are evident, the target distribution cannot be achieved;
The distribution of the charge in the furnace is disturbed, which not only causes fluctuations in the furnace temperature, but also in extreme cases can cause blow-through, shelf IT39, etc.0 (Objective of the Invention) This is a blast furnace system that enables stable furnace operation by reducing irregularities in the charge distribution caused by slips, drops, etc. by controlling the relative falling position of the material during material charging. The object of the present invention is to provide a raw material charging method.

(Summary of the Invention) That is, the present invention is characterized in that the stock level is measured moment by moment while the raw material is being charged into the blast furnace, and the raw material falling position is controlled in accordance with changes in the stock level.

(Specific Example of the Invention) FIG. 1 is a schematic diagram of an apparatus used to carry out the present invention, and shows an example in which the present invention is applied to a bellless blast furnace. The illustrated equipment includes a sounding device that can measure the stock level in the blast furnace during charging of raw materials into the blast furnace; Arithmetic device 2 for determining the charge dropping position according to the stock level measured by the sounding device R1. A control device 4 is provided for controlling the charge distribution device 3 according to commands from the arithmetic device 2 . As the sounding device 1, for example, an ultrasonic type device is suitably used.One or more charge distribution and charging devices 3 are provided, for example, in the north, south, east, and west. The material is distributed and charged from the furnace wall side to the furnace center side by rotating horizontally and gradually tilting vertically. Note that in FIG.

1. Slip or mud during raw material charging.

If a drop occurs, the stock level L drops to L' (FIG. 2). At this time, the tilting angle θ of the charge distribution device 3 is the planned stock level (stock level before descent) L
With reference to 1~, the feed material is set to fall to the target position p on the stock level L, and the raw material has a trajectory f.
Therefore, when the stock level L drops by L't, the raw material is charged from the target position p to the position p' at the mouth of the furnace wall. This results in disturbances in the charge distribution.

Therefore, according to the present invention, in a bellless blast furnace, for example, the relationship between the tilting angle of the chute 3 and the raw material falling position is predetermined as shown in FIG.

In FIG. 3, if the stock level change ΔL is small, the angle change Δθ corresponding to the level change ΔL can be approximated by a straight line, so it can be expressed as Δθ 1T=. The coefficient is determined based on the relationship between the above-mentioned predetermined tilting angle of the chute and the falling position. The required angle change amount corresponding to the stock level change l due to slip or drop is expressed by K and l. Therefore, for a change l in strike and frebel, θ1
By correcting -θo- to the chute tilting angle of -d, the raw material can be charged at the target falling position (on the P line), and the relative falling position of the raw material can be kept constant.

Now, if there is a fluctuation in the stock level L due to slipping or dropping of the charged material during charging, a change in the stock level is detected by the sounding device 1 which measures the stock level L moment by moment. When the stock level change meter l is detected at 7L, the arithmetic unit 2 calculates θ1
=θ6-]<-7 is calculated, and a setting angle correction command for the chute 3 is given to the control device 4. As a result, the set angle of the chute 3 is corrected by 1 degree, and the charge can be dropped onto the target position P.

Although the above embodiments apply the present invention to a bellless type blast furnace, the present invention can also be applied to a bell type blast furnace.

In this case, the raw material falling position is adjusted by controlling the movable armor instead of controlling the sheet angle.

(Effects of the Invention) As described above, according to the present invention, even if the stock level suddenly changes, the relative charge distribution in the radial direction can be maintained by keeping the radial raw material falling position relatively constant. It can be kept constant at all times, and a safe furnace condition can be obtained by changing the temperature. As an example, changes in the difference in hot metal temperature for each tap are shown in FIGS. 4(a) and 4(b). The smaller the difference between directions, the better. In the conventional method, the charging distribution is irregular and there is a difference in the charging in the circumferential direction.
While there is a difference in hot metal temperature depending on the direction of the tap hole, according to the method of the present invention, a good distribution state and a uniform hot metal temperature can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a device implementing the present invention, Fig. 2 is an explanatory diagram showing the relationship between shoot angle and stock level, and Fig. 3 is an explanatory diagram showing the relationship between shoot angle and stock level.
The figure shows the relationship between the sea-1 angle and the position of the charge falling, Figure 4 (a) shows the position of the tap hole, and Figure 4 (b) shows the hot metal temperature at each tap hole. be. 1. Sounding device 2. Computing device 3. Charge distribution device 4. Control device L.. Normal stock level L'.. Stock level P during pickpocketing.. Target drop position P'. Falling position f when angle is not corrected...Raw material falling trajectory Patent applicant: Sumitomo Metal Industries Hata Co., Ltd. Representative Patent Attorney Yoshi Nagai Box 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) A method for charging raw materials into a blast furnace, which is characterized in that the stock level is measured moment by moment during charging of raw materials into a blast furnace, and the position where the raw materials fall is controlled according to changes in the stock level.