JPH06179904A - Pressure equalizing method in charging device for bell type blast furnace - Google Patents

Abstract

PURPOSE:To reduce a production cost in a blast furnace operation by stopping the introduction of inert gas into a small bell hopper, in the case of charging raw material in the small bell hopper into a large bell hopper. CONSTITUTION:Clean blast furnace gas is introduced into the small bell hopper 3 in the condition of closing the small bell 6 incorporating the raw material to execute a primary pressure equalization. By introducing the inert gas into the small bell hopper 3 based on the differential pressure between the small bell hopper 3 and the large bell hopper 4 till charging the following raw material into the small bell hopper 3, a secondary pressure equalization is executed so as to keep the pressures in both hoppers 3, 4 to almost the same. Then, by opening the small bell 6 during the secondary pressure equalization, the raw material in the small bell hopper 3 is charged into the large bell hopper 4. In this case, the introduction of the inert gas in the small bell hopper 3 is stopped. By this method, waste consumption of the nitrogen gas which does not directly affect the pressure equalization in the secondary pressure equalization process can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure equalizing method for a raw material charging device when charging a raw material from the top of a bell type blast furnace to the inside of the furnace.

[0002]

2. Description of the Related Art In high-pressure operation of a blast furnace, pressure equalization and exhaust pressure in the large bell hopper and the small bell hopper are required to open and close the bell and the seal valve. For example, in a raw material charging device composed of a small bell hopper and a large bell hopper, the raw material is charged into the small bell hopper, and from the closed state of the small bell to the opening of the seal valve provided at the upper part of the small bell hopper. The pressure is almost equalized to the pressure at the furnace top, and the pressure in the small bell hopper is discharged to almost atmospheric pressure from the time when this pressure equalization ends to the time immediately before the opening of the seal valve. This pressure equalization is based on the primary pressure equalization that performs coarse pressure equalization using clean blast furnace gas and the secondary pressure equalization that performs insufficient pressure supplementation and fine adjustment pressure equalization using nitrogen gas as an inert gas. Has become.

FIG. 3 is a time chart showing the operation of each device in the conventional secondary pressure equalizing method. In the secondary pressure equalization, according to the raw material charging time schedule, from the start of the secondary pressure equalization until the stop command is issued, that is, after the completion of the primary pressure equalization until the discharge pressure is started. Meanwhile, nitrogen gas is introduced into the small bell hopper so that the pressure difference between the small bell hopper and the large bell hopper is always close to "0". That is, when the secondary pressure equalization start command is issued, the pressure regulator is turned on, the control valve operates based on the output of the pressure regulator, and nitrogen gas flows into the small bell hopper to perform pressure equalization.

When the small bell is opened to load the raw material charged in the small bell hopper into the large bell hopper during the secondary pressure equalization, the moment when the raw material falls, Therefore, the pressure in the small bell hopper becomes lower than the pressure in the large bell hopper. Then, based on the output of the pressure regulator, the regulating valve is actuated again and nitrogen gas flows into the small bell hopper to equalize the pressure. In this case, a large amount of nitrogen gas flows into the small bell hopper in order to eliminate the pressure difference between the small bell hopper and the large bell hopper.

[0005]

However, the pressure difference between the two hoppers caused by the dropping and moving of the raw material from the small bell hopper to the large bell hopper is instantaneous as described above, and the passage of time. Nitrogen gas is being introduced even though it has been resolved due to.

The amount of nitrogen gas introduced is about 45% of the total amount of nitrogen gas used for secondary pressure equalization, and the unnecessary use of nitrogen gas leads to an increase in production cost. Therefore, in order to avoid waste of the nitrogen gas usage amount in the secondary pressure equalization, it is desired to optimize the pressure equalization control method.

[0007]

The present invention has been proposed in view of the above, and introduces a clean blast furnace gas into a small bell hopper containing a raw material and having a small bell closed to perform primary pressure equalization,
After that, until the next raw material is charged into the small bell hopper, the inert gas is introduced into the small bell hopper based on the pressure difference between the small bell hopper and the large bell hopper, and the pressure in the small bell hopper is introduced. And a method for equalizing the pressure in a bell-type blast furnace that performs secondary pressure equalization so as to maintain the pressure in the large bell hopper substantially the same, the small bell hopper is opened by opening the small bell during the secondary pressure equalization. When charging the raw materials in the large bell hopper, the introduction of the inert gas into the small bell hopper is stopped.

[0008]

According to the pressure equalizing method of the present invention, after the primary pressure equalization is performed by the blast furnace gas, the nitrogen gas which is an inert gas is introduced into the small bell hopper by the secondary pressure equalization start command, Secondary equalization is performed so that the pressure difference between the hopper and the large bell hopper becomes almost "0". Here, it is necessary to open the small bell in order to charge the raw material charged in the small bell hopper into the large bell hopper. At this time, a pressure difference occurs between the small bell hopper and the large bell hopper due to the dropping of the raw material. In this case, the pressure difference between the two hoppers does not last long and does not hinder the charging of the raw materials. Even if nitrogen gas is introduced with the small bell open, the nitrogen gas flows into both the small bell hopper and the large bell hopper, so there is little advantage in equalizing the pressure, so the nitrogen gas is small. Do not let it flow into the hopper. Therefore, it is possible to reduce the manufacturing cost without consuming unnecessary nitrogen gas that does not directly affect the pressure equalization in the secondary pressure equalization step.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a blast furnace 1 according to the present invention.
The blast furnace 1 has a raw material hopper 2 at the top of the furnace, a small bell hopper 3 is provided below the raw material hopper 2, and a large bell hopper 4 is provided below the small bell hopper 3. A seal valve 5 is provided between the raw material hopper 2 and the small bell hopper 2 to separate the raw material hopper 2 and the small bell hopper 3 from each other. Further, a small bell 6 is provided between the small bell hopper 3 and the large bell hopper 4 so as to be able to move up and down. Isolate 4 and. Further, a large bell 8 is provided between the large bell hopper 4 and the inside of the furnace 7 so as to be able to move up and down, and when the large bell 8 is pressed against the lower surface of the large bell hopper 4, the large bell hopper 4 and the inside of the furnace 7 are connected. Isolate.

A differential pressure gauge 10 is connected to the small bell hopper 3 and the large bell hopper 4 via pressure pipes 9a and 9b, respectively. And the output from this differential pressure gauge 10 is
It is input to the controller 11. Further, a nitrogen gas supply facility 14 is connected to the small bell hopper 3 via an opening / closing valve 12 and a control valve 13 to supply nitrogen gas used for pressure equalization. The above-mentioned controller 11 is a device for operating the control valve 13 based on the output from the differential pressure gauge 10, and is activated and adjusted based on the secondary pressure equalization start command from the pressure equalization sequencer 15 which is the control means. An actuation signal is sent to the valve 13.

Further, an opening / closing detection switch 16 for detecting the opening / closing of the small bell 6 is connected to the small bell opening / closing shaft 6a, and when the small bell 6 is opened, a small bell opening signal is output to the uniform discharge pressure sequencer 15. . Upon receiving the small bell open signal, the pressure equalizing pressure sequencer 15 deactivates the differential pressure gauge 10 by stopping the secondary pressure equalization start command signal output to the controller 11, and the secondary pressure equalization start command is issued. The transmission of the actuation signal to the control valve 13 is suppressed even while is being issued.

The control operation of the above-mentioned pressure equalization sequencer 15 will be described with reference to the flow chart shown in FIG. When the secondary pressure equalization start command for performing the secondary pressure equalization is output, the monitoring timer is activated to judge the opening / closing operation of the small bell 6. When the open / close detection switch 16 detects the open state of the small bell 6, the state of the monitoring timer is checked, and when the monitoring timer is up, the control valve 13 is fully closed and nitrogen gas is supplied to the small bell hopper 3. Stop the supply. Here, the state of the monitoring timer is checked to prevent the control valve 13 from being fully closed until the small bell 6 slightly moves for some reason and the open / close switch 16 detects the open state. Is. That is, in order to actually load the raw material in the small bell hopper 3 into the large bell hopper 4, the control valve 13 is fully closed only when the small bell 6 is opened.

On the other hand, when the small bell 6 is in the closed state and when the monitoring timer has not timed out, the control valve is automatically controlled to control the amount of nitrogen gas flowing into the small bell hopper 3. And equalize. When the output of the secondary pressure equalization start command is stopped, the control valve 13 is fully closed to stop the supply of nitrogen gas to the small bell hopper 3, and the secondary pressure equalization is ended.

[0014]

As described above, in the present invention, in the pressure equalizing step performed when charging the raw material from the blast furnace top to the inside of the blast furnace, the blast furnace gas is introduced into the small bell hopper to perform the primary pressure equalization. After that, when the secondary pressure equalization start command is issued, the pressure difference between the small bell hopper and the large bell hopper is measured, and based on the measured value, the inert gas is introduced into the small bell hopper and the small bell hopper is introduced. The secondary pressure equalization control is performed so that the internal pressure and the pressure in the large bell hopper are kept almost the same, and during the above secondary pressure equalization control, the raw material charged in the small bell hopper is charged into the large bell hopper. Therefore, even if the small bell is opened, the flow of the inert gas into the small bell hopper is stopped.

That is, the pressure difference between the small bell hopper and the large bell hopper, which occurs when the small bell is opened to load the raw material charged in the small bell hopper into the large bell hopper, does not hinder the charging of the raw material. Therefore, in such a case, the nitrogen gas is controlled so as not to flow into the small bell hopper. Therefore, it is possible to reduce the manufacturing cost in the blast furnace operation without consuming wasteful nitrogen gas that does not directly affect the pressure equalization in the secondary pressure equalization step.

[Brief description of drawings]

FIG. 1 is a schematic view of a blast furnace showing an embodiment of the present invention.

FIG. 2 is a flowchart showing a control operation in a pressure-equalizing pressure sequencer which is a pressure equalizing control means.

FIG. 3 is a time chart showing the operation of each device in the conventional pressure equalizing method.

[Explanation of symbols]

 1 Blast furnace 2 Raw material hopper 3 Small bell hopper 4 Large bell hopper 5 Seal valve 6 Small bell 7 Inside the furnace 8 Large bell 9a, 9b Pressure piping 10 Differential pressure gauge 11 Controller 12 Open / close valve 13 Control valve 14 Nitrogen gas supply equipment 15 Uniform discharge Pressure sequencer 16 Open / close detection switch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshikatsu Goto 1 Nishinosu, Oita-shi, Oita New Nippon Steel Co., Ltd. Oita Works

Claims (1)

[Claims] 1. A clean bell hopper gas is introduced into a small bell hopper in which a small bell is closed and a small bell is closed to perform primary pressure equalization, and thereafter, the next raw material is charged into the small bell hopper. Based on the pressure difference between the small bell hopper and the large bell hopper, an inert gas is introduced into the small bell hopper so that the pressure inside the small bell hopper and the pressure inside the large bell hopper are kept almost the same. In a pressure equalizing method in a charging device of a bell-type blast furnace for performing pressure equalization, when the raw material in the small bell hopper is charged into the large bell hopper by opening the small bell during the secondary pressure equalization, the small bell hopper is used. A method for equalizing pressure in a bell-type blast furnace charging device characterized by stopping the introduction of an inert gas into the interior.