JPS602610A - Operating method of blast furnace - Google Patents

Abstract

PURPOSE:To maintain the uniform reaction in a blast furnace with a bell-less swiveling chute and the satisfactory operation of said furnace by changing the swiveling angular velocity of the swiveling chute with the temp. distribution in the shaft part thereby controlling the gaseous flow distribution in the raw material in the furnace. CONSTITUTION:The temp. in the shaft part of a blast furnace is measured with a thermometer 7 and is fed to a control part 9. Profile meter pairs 3, 3A in the furnace top part detect the surface condition of the raw material with profile display devices 4, 4A respectively and feed the data of an overall recess dispaly part 5 to the part 9. The control part 9 makes overall judgement and gives an instruction to a driving device 6A to change the swiveling angular velocity of a swiveling chute 6 in the circumferential direction thereby changing the raw material surface 2 in the furnace top. The venting of gas around the circumference in the furnace is made uniform by such adjustment by which the internal condition of the furnace is improved and satisfactory furnace operation is maintained.

Description

Detailed Description of the Invention This article relates to a blast furnace operating method for controlling the gas flow distribution in the furnace by controlling the burden distribution in a blast furnace having a bellless rotating chute. In a blast furnace having a rotating chute, charge distribution is controlled by arbitrarily changing the inclination angle of the rotating chute when charging the charge into the furnace. For example, in blast furnace operation, if the gas flow in the furnace is significantly disturbed, the reduction reaction of the ore charged in the furnace becomes unstable, and it is determined that stable operation of the furnace cannot be maintained, the rotation By changing the angle of inclination of the chute, the deposition position of the charge is changed, and the ratio of ore and coke in the radial direction of the furnace is changed, thereby controlling the distribution in order to recover and maintain an appropriate gas flow distribution. . Such a charge distribution control method is characterized in that the charge distribution is changed uniformly in the circumferential direction. Therefore, it is assumed that the change in the gas flow distribution in response to the change in the charge distribution also changes in the circumferential direction.

However, in actual furnace operation, the gas flow distribution is often significantly disturbed in a specific direction not only due to changes in the charge distribution but also due to differences in furnace wall erosion conditions and differences in air blowing conditions in the lower part of the furnace. Unstable directional balance often occurs.

Therefore, in the conventional method of controlling the charge distribution, which changes uniformly in the circumferential direction, if the balance in the circumferential direction is lost,
It is difficult to accurately control the gas flow in the furnace.

The present invention is a charge distribution control method that can control gas flow distribution when such gas flow distribution in a specific direction is significantly disturbed.

The key points of the present invention are as follows. That is, in general S
'Charge distribution control in JP is carried out by adjusting the charging position of coke, ore, etc. based on the V-shaped (striped forest) piled shape of the burden. In this case, the most concave part of the figure 7-shaped charge distribution shape usually coincides with the center of the furnace. Therefore, the gas flow distribution in the furnace shows a distribution in which lines of the same temperature and concentration are formed concentrically from the center of the furnace.

However, the amount of charge in a specific direction (orer coke)
When the amount increases, the gas flow velocity in that direction is suppressed and the concentric gas flow distribution becomes distorted in response to changes in the charging amount.

Therefore, if the gas flow distribution is disturbed due to changes in the furnace wall erosion, etc., the gas flow distribution can be restored to a concentric pattern by changing the charge amount in the circumferential direction, and stable operation can be maintained. is possible.

On the other hand, as a means of detecting disturbances in the gas flow distribution in the furnace, the detection end is generally inserted directly into the furnace to detect the temperature of the gas in the furnace.
A method is used to measure components, etc., but in order to measure disturbances in the circumferential gas distribution using this method, detection ends must be installed in multiple directions, and there are moderate restrictions on the equipment, so it is not sufficient. There is no proper measurement system in place. Therefore, as a simple means, a method is often used in which a multidirectional RC thermometer is embedded in the furnace wall and the temperature change is understood as a change in the amount of heat load on the furnace wall due to the disturbance of the gas flow in the furnace.

According to the present invention, the amount of heat load that corresponds to the change in gas flow in the furnace is grasped as a temperature difference from the thermometer in the circumferential direction of the furnace wall, and this temperature difference is determined as a trend within a predetermined control range. The object of the present invention is to control the charge distribution so that the most concave part of the V-shaped distribution of the charge pile shape changes using the charge distribution control device when the charge distribution varies widely.

The present invention will be explained below based on the drawings. FIG. 1 shows a control system diagram of a blast furnace having a bellless rotating chute in an embodiment of the present invention.

1 is the blast furnace main body, 2 is the charging surface showing the shape of the charge piled up, 3
, 3A is a profilometer that measures the piled shape of the charge in a cross shape, 4.4A is an indicator that shows the piled shape of the charge measured by the profilometer, and 5 is a meter that measures the piled shape of the charge as a uniform height. 6 and 6A are the rotating chutes and their driving devices; 7 is a thermometer installed on the wall of the furnace shaft; 8 is an indicator showing the temperature deviation in the circumferential direction; 9 is the rotating chute 6; This is a controller for adjusting the turning method.

Based on the present invention, the charge distribution control is performed by displaying the indicator 8. 4 = The furnace wall temperature in the shaft section exceeds the control range in a specific direction in the circumferential direction, and the heat load on the furnace wall changes in this direction. When this is confirmed, the controller 9 drives the drive device 6A to continuously change the swing angular velocity of the swing chute 6 such that it increases on the side with a low heat load and decreases on the side with a high heat load. By doing this, on the side where the angular velocity of the rotating chute 6 is small,
The amount of charge becomes relatively large, and on the other hand, the amount of charge decreases on the larger side, so the shape of the charge pile changes and the most concave part of the figure 7 moves to the side where less charge is charged. . As a result, more gas in the furnace flows in the direction where the amount of charge is smaller, that is, in the direction in which the most concave portion of the figure 7 shape has moved, and the heat load in that direction gradually increases.

On the other hand, on the opposite side to the direction in which the most concave portion has moved, the gas flow is suppressed and the heat load changes in the direction of decreasing.

In controlling the charge distribution, it is important to constantly monitor the movement of the V-shaped recessed portion of the charge distribution using a profile meter or the like arranged in a cross shape. In other words, the charge deposition shape 1 is affected by the gas flow distribution in the furnace, the phase velocity of the charge descending speed, etc., and the direction of the angular velocity adjustment of the rotating chute and the direction of the deviation at the most concave part are This is because they do not always match.

The direction of deviation of the gas flow distribution in the furnace is always the same as that in the most concave part IS, because the gas flow velocity is highest at the most concave part IS, in the range where a charging method aiming at a V-shaped approximation of the charge deposition shape is adopted. changes in accordance with the direction of movement.

Examples of operational results to which the present invention is applied are shown in FIGS. 2 and 3.

Figure 2 (a) shows the bellless rotating chute type charging device VC.
This figure shows the relationship between the rate of change in the swing angular velocity of the chute and the moving distance (L) of the most concave portion of the charge distribution.

(Figure 2 (B) is a diagram showing all the directions of the moving distance of the most concave 'tfls) The rate of change in the chute rotation angular velocity is the angular velocity 1fVmax in the direction of moving the most concave part of the charge deposition shape.
and the angular velocity min on the axially symmetric side in this direction. As is clear from the figure, the most concave portion moves by 30 cm due to this and V. 1st, the most concave part f at the axis center By setting tnax to the 0° side, the most concave part is 0
Move 30cm to the ° side.

In this example, the furnace internal volume is 1200? ? ? ! In the blast furnace, the charge amount is 80 tons of coke per charge and 2 ores +7.2
In the case of t, y mt / V min ,! :
Since the relationship with L varies depending on the temperature of the blast furnace, the amount of charge, etc., it is desirable to understand it in advance using an offline model or an actual furnace.

Figure 3 is an explanatory diagram of the implementation results. Figure 3 (a) shows the transition of furnace wall temperature in the upper part of the blast furnace shaft in the circumferential direction O0 and 1800 directions, and Figure 3 (b) shows the change in the furnace wall temperature in the circumferential direction O0 and 1800 directions. The amount of movement of the concave portion when the most concave portion of the charge deposition shape is moved by controlling the angular velocity of the rotating chute based on the invention is shown. In FIG. 3(a), there was a tendency for the furnace wall temperature to gradually increase on the 180° side, while decreasing on the O0 side. Due to the temperature change between
It was predicted that the circumference balance would be disrupted so that the number would increase on the 00 side. Therefore, according to the present invention, an action was taken to change the angular velocity of the rotating chute, and a charge distribution control action was taken to shift the recessed part to 00 Tsukuda. As a result, the circumferential balance of the furnace wall temperature was in the direction of recovery, and a drastic deterioration of the operating conditions could be avoided.

As described above, the present invention also detects disturbances in the circumferential balance of the gas flow distribution in the furnace from changes in the furnace wall temperature, etc.
In response to this change, by controlling the angular velocity of the bellless rotating chute and moving the most concave part of the charge deposition shape, it is possible to suppress disturbances in the gas flow distribution in the furnace and restore the furnace condition. . In the embodiment of the present invention, an example was shown in which the disturbance in the circumferential balance of the gas flow distribution in the furnace is understood as a change in the furnace wall temperature, but as is clear from the configuration of the present invention, the gas flow in the furnace If changes in the circumferential balance of distribution can be measured, for example, a heat load meter can be used.

It is also possible to use information such as stave temperature and wall gas thermometer.

[Brief explanation of the drawing]

FIG. 1 is a control system diagram showing an embodiment of the present invention, FIG. 2 (A) is a diagram showing the relationship between the angular velocity of the swinging chute and the moving distance of the recessed part according to the present invention, and FIG. A diagram showing the direction of the travel distance of the most concave part, Figure 3) is a diagram of the change in furnace wall temperature, Figure 3
Figure (b) is a diagram showing the transition of the position of the most concave portion in the embodiment of the present invention. ]4...Furnace body 2...Charging surface 3.3A...Profile meter 4.4A...
... Profile display 5 ... ... Concave section display 6 ... ... Rotating chute 6A ... Drive device 7 ... Thermometer 9 ... Control Applicant Nippon Steel Corporation 11- Figure 1 Figure 2 (A) (Ron TMAV side;

Claims (1)

[Claims] In a blast furnace having a bellless rotating chute, measuring the temperature distribution or heat load distribution in the circumferential direction of the blast furnace shaft,
If a significant deviation occurs in a particular direction, the angular velocity of the rotating chute is changed in the circumferential direction to change the concavity of the burden deposition shape, thereby controlling the gas flow distribution in the furnace and stabilizing the circumferential balance. A method of operating a blast furnace characterized by: