A method for automatically controlling the opening of a converter double throat

Abstract

The present application relates to a kind of automatic control converter two text throat opening degree method, according to converter blowing process, when converter is in the state of charging, when converter blowing reaches slag point, when converter blowing reaches slag point, before converter lance process test, when molten steel temperature approaches smelting endpoint, by smoke analyzer, flame machine vision device, audio signal acquisition device acquisition furnace top gas gas content, the change of light intensity of converter furnace mouth or the light intensity of lower edge of converter furnace mouth, the data information of converter blowing sonar slag measurement value, and the collected data information is transmitted to PLC / DCS system, when converter is in the state of charging, realize the opening degree of automatic control converter two text throat in converter blowing process.The present application has the advantages that: without manual intervention, reduce smoke overflow, improve the coal gas recovery rate, maintain production safety.

Description

Technical Field

[0001] This invention relates to the field of converter gas recovery technology, and in particular to a method for automatically controlling the opening of the second throat of a converter. Background Technology

[0002] In converter steelmaking, the control of the second vent of the flue is crucial. Poor control can lead to the following problems: affecting the gas recovery rate and impacting carbon emissions from negative energy steelmaking; easily causing smoke and dust to spill out, affecting environmental protection; and easily causing flames to burn the plant frame and platform equipment, endangering production safety.

[0003] Existing methods for controlling the throat of a second vessel include the following:

[0004] 1. Manual control by observing the fire: If the smoke and fire become too large, manually adjust the opening of the two nozzles.

[0005] 2. Automatic adjustment of differential pressure at the furnace mouth: This method cannot be used normally because the pressure tap is located inside the fume hood, in a harsh environment, and is often blocked by hot smoke, slag, and splashes.

[0006] 3. A static mode adjustment method, which sets a fixed opening degree at fixed times based on big data; Publication number CN107630120B discloses "An adjustment method for the second throat of a converter," the content of which is as follows:

[0007] 1) During the process of adding scrap steel to iron, the opening of the second mortise should be controlled at 40% to 50%;

[0008] 2) During the silicon-manganese oxidation period before the oxygen blowing volume reaches 20%, the opening degree of the RD valve should be controlled at 50% to 60%;

[0009] 3) During the intense carbon-oxygen oxidation period when the oxygen blowing volume is 20% to 75%, the opening degree of the RD valve should be controlled at over 90%.

[0010] 4) After the oxygen blowing rate reaches 75%, the opening degree of the RD valve should be controlled between 65% and 75%.

[0011] 5) At the start of the secondary gun process test, the opening of the RD valve should be controlled at 50% to 60%;

[0012] 6) After oxygen blowing is completed, the opening degree of the RD valve should be controlled at 40% to 50%;

[0013] The drawback is that the adjustment method is a static control of the two throat openings.

[0014] 4. An automatic mode adjustment method, disclosed in CN105154615B, entitled "An automatic adjustment device and method for the second throat of a converter," breaks through the traditional micro-differential pressure control method of the furnace mouth pressure sensor. It adds a gas analyzer sensor, an oxygen analyzer sensor, an oxygen lance position sensor, and an oxygen regulating valve position sensor, which are respectively installed on the side of the flue gas pipeline of the blower and the three-way valve. The signals of carbon monoxide content, oxygen content, and oxygen lance position are used as indicators. The hydraulic station of the throat is controlled by PLC. When all the detection signals meet the requirements, the weight moves downward to the specified position. When any of the detection signals does not meet the requirements, the weight moves upward and returns to the initial position, thereby realizing the automatic control and adjustment of the second throat of the converter. It uses gas content to dynamically control the second throat, but its drawback is that the variable is singular. Summary of the Invention

[0015] The purpose of this invention is to provide a method for automatically controlling the opening of the second throat of a converter. When the converter starts blowing, the opening of the second throat of the converter is automatically controlled by multiple variables, such as the charging status, the change in the gas content of the converter top gas, the change in the light intensity of the converter mouth or the light intensity of the lower edge of the mouth, and the slag measurement value of the blowing sonar. This reduces the overflow of smoke and dust during steelmaking, improves the gas recovery rate, and maintains production safety.

[0016] To achieve the above objectives, the present invention provides the following technical solution:

[0017] A method for automatically controlling the opening of the second throat of a converter, based on a PLC / DCS system, uses an empirical value before the start of blowing as the initial value for the opening of the second throat. When the converter starts blowing, the method specifically includes the following:

[0018] 1) When the converter is in the charging state, the opening of the second throat of the converter is set as follows: the opening is increased by one based on the initial value, and the setting time is maintained for one time before returning to the initial value;

[0019] 2) When the converter reaches the slag point during the blowing process, if the sum of the carbon monoxide concentration and carbon dioxide concentration in the top gas is greater than the set value one, or the carbon dioxide concentration in the top gas is greater than the set value two, the opening of the converter's second throat is set to: increase the opening by two based on the initial value, maintain the setting time two, and then return to the initial value.

[0020] 3) When the slag reaches the point of arrival during converter blowing, the following steps are included:

[0021] Step S1: When the light intensity value at the converter mouth is less than the set threshold one, the opening of the converter throat is set to: increase the opening by three based on the initial value, and maintain it until the light intensity value at the converter mouth recovers to the set threshold one and then returns to the initial value.

[0022] Step S2: When the light intensity value at the lower edge of the converter mouth is greater than the set threshold two, the opening of the converter throat is set to: increase the opening by four based on the initial value, and maintain it until the light intensity value at the lower edge of the converter mouth recovers to the set threshold two and then returns to the initial value.

[0023] 4) When the slag is blown into the converter and the sonar slag value falls into the dry return zone, the opening of the second slag throat of the converter is set as follows: reduce the opening by five based on the initial value, and maintain it until the sonar slag value leaves the dry return zone and then returns to the initial value.

[0024] 5) Before the converter auxiliary lance process test, if a sudden drop in the sum of carbon monoxide and carbon dioxide concentrations in the top gas is detected, and the sonar slag measurement value falls in the splash zone, the opening of the converter second lance throat is set as follows: the opening is increased by six based on the initial value and maintained until the sonar slag measurement value leaves the splash zone, or until the slope of the sum of carbon monoxide and carbon dioxide concentrations in the top gas is greater than zero, then it returns to the initial value.

[0025] 6) When the temperature of the molten steel is close to the end of the smelting process, the brightness of the furnace mouth increases, and the opening of the second throat of the converter is restored to the initial value.

[0026] The slag measurement value of the converter sonar is the sound intensity value of a sound at a fixed frequency.

[0027] The carbon monoxide and carbon dioxide concentrations in the top gas are detected by a flue gas analyzer, which is located at the end of the rising section of the converter waste heat boiler vaporization cooling flue. The light intensity value at the converter mouth or the intensity value at the lower edge of the converter mouth is detected by a flame machine vision device, which is located directly opposite the converter fire baffle. The sonar slag measurement value is detected by a flame machine vision device, which is located on the converter trunnion sidewall directly opposite the mouth.

[0028] The flame machine vision device includes a camera, a sound sensor, a flue gas analyzer, and is connected to a PLC / DCS system.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] The system collects data on gas content at the top of the furnace, light intensity at the converter mouth or along the lower edge of the converter mouth, and slag measurement values ​​using sonar during converter blowing by a flue gas analyzer, flame machine vision device, and audio signal acquisition device. The collected data is then transmitted to the PLC / DCS system. When the converter is in a charging state, the system automatically controls the opening of the second throat of the converter and the gas recovery rate during the converter blowing process, thus maintaining production safety. Attached Figure Description

[0031] Figure 1This is a schematic diagram of a method for automatically controlling the opening of the second throat of a converter.

[0032] Figure 2 It is a test curve of the converter steelmaking blowing process.

[0033] Figure 3 This is a schematic diagram of the throat control principle.

[0034] In the diagram: 1-Flame machine vision device; 2-Audio signal acquisition device; 3-Flue gas analyzer; 4-Converter waste heat boiler vaporization cooling flue. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0036] The following embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments. Unless otherwise specified, the methods used in the following embodiments are conventional methods.

[0037]

Example 1

[0038] The main reasons for flue gas overflow during converter steelmaking are as follows:

[0039] 1. Dust may overflow when the converter is being fed;

[0040] 2. When molten steel splashes, fumes will escape.

[0041] 3. When the carbon monoxide or carbon dioxide produced during the blowing process changes suddenly, the flue gas will overflow.

[0042] To address the three reasons mentioned above, data on changes in the gas content of the furnace top gas, changes in the light intensity at the converter mouth or the lower edge of the converter mouth, and converter sonar slag measurement values ​​(the sonar slag measurement value is the sound intensity value of a fixed frequency sound) are collected using a flue gas analyzer, a flame machine vision device, and an audio signal acquisition device. This collected data is transmitted to the PLC / DCS system. When the converter is in a charging state, the opening degree of the converter's second throat is automatically controlled during the converter blowing process. See [link to relevant documentation]. Figure 1A method for automatically controlling the opening of the converter's second throat is described. The carbon monoxide and carbon dioxide concentrations in the top gas are detected by a flue gas analyzer 3, which is positioned before the descending section at the end of the rising section of the converter waste heat boiler vaporization cooling flue 4. Strong light is generated at the lower edge of the converter mouth during molten steel splashing; the light intensity value at the converter mouth or the intensity value at the lower edge of the converter mouth is detected by a flame machine vision device, which is positioned 20 meters directly opposite the converter's fire baffle, with the flame at the converter mouth visible to the camera during steelmaking. Slag values ​​are measured using sonar via an audio signal acquisition device. For testing, the audio signal acquisition device is set on the side wall of the converter trunnion, directly opposite the gap between the furnace mouth and the fume hood; the flame machine vision device includes a camera, which is used to detect the furnace mouth area and the lower edge area of ​​the furnace mouth, detect changes in the light intensity at the furnace mouth and whether there is slag overflow at the lower edge of the furnace mouth; the audio signal acquisition device includes a sound sensor and an audio transmitter, the sound sensor converts the acquired signal into a 4-20mA signal through the audio transmitter, and the sound sensor of the audio signal acquisition device is used to detect the sonar slag measurement value; the flue gas analyzer, the flame machine vision device, and the audio signal acquisition device are all connected to the PLC / DCS system.

[0043] See Figure 2 ,See Figure 3 'a' represents the furnace mouth light intensity detection curve, 'b' represents the sonar curve, 'c' represents the curve of carbon monoxide plus carbon dioxide, 'd' represents the carbon dioxide curve, and 'e' represents the carbon monoxide curve. Before starting the blowing process, the opening of the second furnace throat is set to 65% based on manual experience. The specific steps at the start of the blowing process include:

[0044] 1) When the converter is in the charging state, the opening of the second throat of the converter is set as follows: increase the opening by 5% on the basis of the initial value to 70%, and maintain it for 20 seconds before returning to the initial value;

[0045] 2) When the converter reaches the slag point during the blowing process, if the carbon monoxide concentration in the top gas exceeds the set value by 20% to 27%, or if the carbon dioxide concentration in the top gas starts to decrease from its rising value, the smoke and dust will begin to increase and tend to splash. The opening of the converter's second throat is set to: increase the opening by 10% based on the initial value of 65%, and maintain it for 1 minute before returning to the initial value.

[0046] 3) When the slag reaches the point of arrival during converter blowing, the following steps are included:

[0047] Step S1: When the light intensity value at the converter mouth is less than the set threshold 27, the flue gas is too large and blocks the light. The opening of the converter's second throat is set to: increase the opening by 10% based on the initial value of 65%, and maintain it until the light intensity value at the converter mouth recovers to the set threshold 32 and returns to the initial value.

[0048] Step S2: When the light intensity value at the lower edge of the converter mouth is greater than the set threshold of 50, steel slag overflows to the lower edge of the mouth. The opening of the converter's second throat is set to: increase the opening by 10% based on the initial value of 65%, and maintain it until the light intensity value at the lower edge of the converter mouth returns to the set threshold of 45 and then returns to the initial value.

[0049] 4) When the converter blows the slag to the slag point, and the sonar slag value falls in the dry return zone, the flue gas generated at this time is reduced. The opening of the converter's second throat is set to be reduced by 10% based on the initial value of 65%, and maintained until the sonar slag value leaves the dry return zone and returns to the initial value, in order to increase the gas recovery rate.

[0050] 5) Before the converter auxiliary lance process test, if the sum of the detected carbon monoxide concentration and carbon dioxide concentration suddenly drops and the sonar slag measurement value falls in the splashing area, it means that molten steel splashing is about to occur. The opening of the converter second lance throat is set to: increase the opening by 10% on the basis of the initial value of 65%, and maintain it until the slope of the sum of carbon monoxide concentration and carbon dioxide concentration is greater than zero or the sonar slag measurement value leaves the splashing area, then return to the initial value.

[0051] 6) When the temperature of the molten steel is very high and close to the end of smelting, when the furnace mouth light intensity value increases to the set threshold of 72, restore the opening of the converter second throat to the initial value of 65%.

[0052] This invention collects data on the gas content of the furnace top gas, the light intensity at the converter mouth or the change in light intensity at the lower edge of the converter mouth, and the sonar measurement value of the converter blowing process using a flue gas analyzer, a flame machine vision device, and an audio signal acquisition device. The collected data is then transmitted to a PLC / DCS system. When the converter is in a charging state, the opening of the second throat of the converter is automatically controlled during the converter blowing process without manual intervention, reducing the leakage of smoke and dust, improving the gas recovery rate, and maintaining production safety.

Claims

1. A method for automatically controlling the opening degree of the second throat of a converter, implemented based on a PLC / DCS system, characterized in that, The experience value before the start of blowing is used as the initial value for the opening of the converter's second throat. When the converter starts blowing, the following are specifically included: 1) When the converter is in the charging state, the opening of the second throat of the converter is set as follows: the opening is increased by one based on the initial value, and the setting time is maintained for one time before returning to the initial value; 2) When the converter reaches the slag point during the blowing process, if the sum of the carbon monoxide concentration and carbon dioxide concentration in the top gas is greater than the set value one, or the carbon dioxide concentration in the top gas is greater than the set value two, the opening of the converter's second throat is set to: increase the opening by two based on the initial value, maintain the setting time two, and then return to the initial value. 3) When the slag reaches the point of arrival during converter blowing, the following steps are included: Step S1: When the light intensity value at the converter mouth is less than the set threshold one, the opening of the converter throat is set to: increase the opening by three based on the initial value, and maintain it until the light intensity value at the converter mouth recovers to the set threshold one and then returns to the initial value. Step S2: When the light intensity value at the lower edge of the converter mouth is greater than the set threshold two, the opening of the converter throat is set to: increase the opening by four based on the initial value, and maintain it until the light intensity value at the lower edge of the converter mouth recovers to the set threshold two and then returns to the initial value. 4) When the slag is blown into the converter and the sonar slag value falls into the dry return zone, the opening of the second slag throat of the converter is set as follows: reduce the opening by five based on the initial value, and maintain it until the sonar slag value leaves the dry return zone and then returns to the initial value. 5) Before the converter auxiliary lance process test, if a sudden drop in the sum of carbon monoxide and carbon dioxide concentrations in the top gas is detected, and the sonar slag measurement value falls in the splash zone, the opening of the converter second lance throat is set as follows: the opening is increased by six based on the initial value, and maintained until the sonar slag measurement value leaves the splash zone, or until the slope of the sum of carbon monoxide and carbon dioxide concentrations in the top gas is greater than zero, then it returns to the initial value. 6) When the temperature of the molten steel is close to the end of the smelting process, the brightness of the furnace mouth increases, and the opening of the second throat of the converter is restored to the initial value.

2. The method for automatically controlling the opening degree of the second throat of a converter according to claim 1, characterized in that, The sonar measurement value is the sound intensity value of a sound at a fixed frequency.

3. The method for automatically controlling the opening degree of the second throat of a converter according to claim 1, characterized in that, The carbon monoxide and carbon dioxide concentrations in the top gas are detected by a flue gas analyzer, which is located at the end of the rising section of the converter waste heat boiler vaporization cooling flue. The light intensity value at the converter mouth or the light intensity value at the lower edge of the converter mouth are detected by a flame machine vision device, which is located directly opposite the converter fire baffle. The sonar slag measurement value is detected by an audio signal acquisition device, which is located on the converter trunnion sidewall directly opposite the mouth.

4. The method for automatically controlling the opening degree of the second throat of a converter according to claim 3, characterized in that, The flame machine vision device includes a camera, and the audio signal acquisition device includes a sound sensor. The smoke analyzer, the flame machine vision device, and the audio signal acquisition device are all connected to the PLC / DCS system.

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