JPS58120707A - Controlling method for recovering of converter waste gas - Google Patents

Abstract

PURPOSE:To suppress the combustion of converter waste gases as far as possible and to recover the waste gases of high calorific value stably in the stage of recovering the waste gases by the use of noncombustion type treating installations for waste gases by controlling the pressure in the furnace port in accordance with the patterns of the concn. of the gaseous Co in the waste gases to be set in association with the materials to be blown. CONSTITUTION:A hood 3 is mounted between the port 1a and flue 2 of a converter 1, and further a skirt 4 is provided between the hood 3 and the converter 1. The skirt 4 is used to shut off the intrusion of air through the port 1a into the converter 1 and the flue 2 by closing the port 1a. Now, the measured value of the pressure in the furnace port measured with a pressure gage P0 mounted to the upper hood 3a constituting the hood 3 is converted to an electric signal with a transmitter 5 for the pressure in the furnace port. Said signal is transmitted to a control device 100 for recovering of waste gases. The measured value of the concn. of the gaseous CO in the waste gases meausred with a gas analyzer Q1 provided on the converter 1 side in the position where a primary dust collector 2b of the flue 2 is installed is converted to an electric signal with a transmitter 8 for the concn. of the gaseous CO. Said signal is transmitted to the device 100. The pressure in the furnace port of the cascade is set in a control circuit for the pressure in the furnace port in accordance with the feedback signal from the transmitter 8.

Description

Detailed Description of the Invention The present invention is a method for recovering converter waste gas using non-combustion type light gas processing equipment, which suppresses combustion of waste gas as much as possible and stabilizes waste gas with a high calorific value. and how to recover it.

The waste gas generated by converter blowing is highly concentrated, containing fine iron oxide powder. The main product is CO gas, but methods for processing this single tail gas are broadly divided into combustion type and non-combustion type. The combustion cloth gas treatment method is a method in which the CO gas is combusted by blowing sufficient air necessary for the combustion of the CO gas into the waste gas, and the combustion heat is recovered as steam in a boiler. In the waste gas treatment method, a skirt is installed between the converter mouth and the flue to block air from entering from the converter mouth and adjust the furnace mouth pressure to recover the unburned waste gas. However, with the recent increase in the size of converter furnaces, it is also necessary to increase the size of waste gas treatment equipment, so non-combustion type waste gas treatment equipment, which requires a relatively small overall device, is the main choice for large converters. has been adopted.

Now, in the non-combustion type waste gas treatment method, it is required to suppress the combustion of waste gas at the furnace mouth as much as possible and recover waste gas with a high calorific value. In order to satisfy this requirement, the operator monitors the air intake and exhaust gas discharge conditions at the converter mouth, and adjusts the opening of the damper installed in the flue and the relationship between the converter mouth and the flue. The pressure at the furnace mouth was controlled by changing the position of the skirt installed in between. In such a method, there are individual differences in the furnace operating skills of operators, and there is considerable variation in the CO gas concentration of the recovered waste gas, making it difficult for the waste gas with a high calorific value to last stably.

Recently, the gas components of waste gas are measured in the flue, and the results are used to predict the amount of dead gas sucked into the flue from the converter, and the waste gas flow rate is automatically adjusted based on the predicted value. A control method has been proposed, but since this method is based on the flow rate of the waste gas, it is not sufficient to recover the waste gas unburned and to stably recover waste gas with a high calorific value. .

The present invention was made in view of certain circumstances, and when recovering converter waste gas using non-combustion type waste gas treatment equipment, the combustion of waste gas is suppressed as much as possible, and a high calorific value is produced. The purpose is to provide a method for stably recovering waste gas.

The converter waste gas recovery control method according to the present invention is a method for recovering converter waste gas using non-combustion type waste gas processing equipment, in which the waste gas in the waste gas is set in association with the material to be subjected to blowing. It is characterized by controlling the furnace mouth pressure based on the COO gas degree pattern.

The method of the present invention will be explained in detail below based on the drawings showing its implementation state. FIG. 1 is a schematic diagram showing the implementation state of the method of the present invention. 1 is a converter, 2 is a flue, and the space between the converter 1 and the door 3, which is housed in the opening of the flue 2 which is connected to the converter 1, has a vertical direction. Skirt 4
is provided. The skirt 4 is used to close the furnace opening 1a of the converter 1 and block air from entering the converter 1 and the flue 2 from the furnace opening 1a. Hood 3 is on top 7
- It consists of a hood 3a and a lower hood 3b, and the upper hood 3aK houses a pressure gauge Po to measure the furnace mouth pressure. And pressure gauge P. The furnace mouth pressure measured value is converted into an electrical signal by the furnace mouth pressure transmitter 5 and transmitted to the waste gas recovery control device 100.

The flue 2 cools the converter gas generated from the converter 1 in the radiant part 2a, and furthermore, the flue 2 cools the converter gas generated from the converter 1.
After dust treatment is performed in the secondary dust collector 2b and the secondary dust collector 2C, the converter waste gas is sucked by the IDF (induced draft fan) 2d and the booster 7 ann 2C and guided to the flue end 2f. The waste gas is stored in a gas holder (not shown) through a recovery valve 9, but when not being recovered, the waste gas, which poses no risk of air pollution, is discharged into the atmosphere from a chimney 10.

A pressure gauge P1 is installed in the radiation section 2a, and a pressure gauge P1 is installed in the radiation section 2a.
A gas analyzer Q1 is installed on the converter l side where the secondary dust collector 2C is installed, and a pressure gauge pt is installed on the converter 1 side where the secondary dust collector 2C is installed. A pressure gauge P3 is installed on the side of the chimney 10 where the booster fan 2e is installed, and a flow meter R1 is installed on the flue end 2f, and these can obtain maintenance management information. used for

COO in the waste gas measured by the gas analyzer Q
The gas level measurement value is measured using electricity (g) by the COO gas level transmitter 8.
The data is converted into a code and transmitted to the waste gas recovery control device 100.

FIG. 2 shows details of the waste gas recovery control device 1i100, including a furnace mouth pressure adjustment circuit 101, a COO gas degree adjustment circuit 102,
, a manual setting circuit 104, and a changeover switch 105, the waste gas recovery control device 100 uses the various conditions of the char to be processed next from the process control ωV computer 200 to determine the material group and predict the jml during blowing. Data regarding the result of the calculation is input. In the waste gas recovery control device 100,
The COO gas level adjustment circuit 102 stores data regarding the CO gas concentration Bakshin for each material group of the blowing material, and the COO gas level adjustment circuit 102#-1t, as described above (
4) Select the COO gas pattern of the charge to be processed based on the data input from the process control computer 200 and the data stored in the process control computer 200, and
Furnace pressure adjustment circuit 101 to control COO gas level based on feedback signal t/C from OO gas level transmitter 8
Set the furnace pressure on the hecascade.

In order to control the furnace mouth pressure based on the furnace mouth pressure set value and the feedback signal from the furnace mouth pressure transmitter 5, the furnace mouth pressure regulating circuit 101 transmits a signal related to the control wax to the exhaust gas recovery It is output to the hydraulic operating device 6 as an output signal of the control device 100.

In addition, the 67 change switch 105 allows the operator to manually set values instead of the above-mentioned values from the COO gas level adjustment circuit 102. It is input from the IJ setting device 104 to the furnace mouth pressure adjustment circuit 101, and the furnace mouth pressure adjustment circuit 101 I/
In order to control the furnace mouth pressure based on the set value, it is now possible to output a signal related to the control amount to the hydraulic operating device 6 as an output signal from the waste gas recovery control system [100]. There is.

The hydraulic operating device 6 that has received the output signal of the waste gas recovery control device 100 operates the hydraulic cylinder 6a based on the signal. The linear movement of the hydraulic cylinder 6a opens and closes the damper 7 provided at the installation position of the secondary dust collector 2c, controls the opening and closing of the flue 2, and adjusts the furnace mouth pressure. It has become.

FIG. 3 shows an example of the Co gas concentration pattern (in the case of low carbon steel) in the converter waste gas stored in the CO gas concentration adjustment circuit 102, with the blowing time plotted on the horizontal axis and the CO gas concentration pattern plotted on the vertical axis. It shows the gas concentration. That is, the CO gas concentration was kept constant at y1% (approximately 50%) for 11 minutes from the start of blowing, and then the CO gas concentration increased to 72% (60%) over t2 minutes.
~70%) Gradually increase until K is reached, and CO gas concentration is 72%.
The pressure was kept constant for 13 minutes in this state, and then the CO gas concentration was gradually increased over t4 minutes until it reached 13% (80-90%), and then kept constant for a predetermined period of time (1x minutes). After holding, the CO gas concentration was 74% by ts sorting.
(approximately 50%) until the CO gas concentration reaches 74%.
The blowing is completed by keeping the % and round flk constant for t6 minutes.

Then, a predetermined period of time during which the CO gas concentration is kept constant at 78% [8 is a value determined by the following equation (1) using the scheduled blowing time tB' calculated by the process control computer 200K.

Lx = tB (t!+ b+ ts+, t4+
ts ten, ta) ... (1) Such Co
The gas concentration patterns are classified and stored according to the material groups of the blowing materials, such as high carbon steel, medium carbon steel, low carbon steel, and two or three other special steels.

The furnace mouth pressure adjustment circuit 101K has an upper and lower limit limiter function for the furnace mouth pressure setting, and is designed to prevent the furnace mouth pressure setting from becoming abnormally high or abnormally low. It has become.

When treating converter waste gas using the converter waste gas treatment equipment configured as described above, first, before blowing, the process control computer 200K determines the material group of the blowing material and calculates the blowing time. Using the results, the CO gas concentration adjustment circuit 102 determines the Co gas concentration pattern of the charge to be processed next, and adjusts the damper 7 to control the furnace mouth pressure based on the Co gas concentration pattern. So,
The pressure at the furnace mouth, which directly affects the combustion of waste gas at the furnace mouth, can be reliably controlled, suppressing the combustion of waste gas as much as possible, and stably recovering waste gas with a high calorific value. be able to.

In addition, in this embodiment, since the furnace mouth pressure adjustment circuit 101 is provided with an upper and lower limit limiter function for the furnace mouth pressure setting, the furnace mouth pressure can be kept within the upper and lower limits, and abnormalities in the furnace mouth pressure control can be prevented. can be prevented.

Furthermore, in this embodiment, since it is possible to switch from the above-mentioned in-house control to manual control using the changeover switch 105, even if an abnormality such as slopping occurs during converter blowing, the operator can perform manual control. can be dealt with.

As described in detail above, the present invention provides a method for recovering converter waste gas using non-combustion type waste gas treatment equipment, based on a Co gas concentration pattern set for each material group of materials to be subjected to blowing. Since the mouth pressure is controlled, combustion of the waste gas can be suppressed as much as possible, and waste gas with a high calorific value can be stably recovered. Therefore, the present invention provides an extremely excellent method for efficiently recovering waste gas and promoting automation of converter operations.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the implementation state of the method of the present invention, Fig. 2 is a schematic diagram showing the waste gas recovery control device, and Fig. 3 is a graph showing an example of the Co gas concentration pattern in the converter waste gas. . 1... Converter 2... Flue 3... Hood 4...
・Skirt 5... Furnace pressure transmitter 7... Damper
8... CO gas concentration transmitter 100... Waste gas recovery control device 101... Furnace pressure adjustment circuit 102...
・CO gas concentration adjustment circuit 200...Process control Hunbuek patent Applicant: Sumitomo Metal Industries Co., Ltd. Agent Patent attorney: Noboru Kono 6a Figure 2 VJ B Figure

Claims (1)

[Claims] 1. In a method of recovering converter waste gas using non-combustion type waste gas treatment equipment, based on the pattern of CO gas in the waste gas that is set in association with the material to be subjected to blowing,
A converter waste gas recovery control method characterized by controlling furnace port pressure.