An automatic control method for implementing the RD valve of a purification system

Abstract

The present invention discloses an automatic control method for realizing the RD valve of a purification system, which relates to automatic control technology. Calibrate the maximum air pressure value P in the primary dust removal and purification system of the converter under the maximum emission condition 0 and the maximum exhaust gas volume Q 0 ; Collect in real time the carbon monoxide content Q of the gas in the primary dust removal and purification system of the converter CO , the carbon dioxide content Q CO2 and the real-time temperature T; According to the maximum air pressure value P 0 , the maximum exhaust gas volume Q 0 the carbon monoxide content Q CO and the carbon dioxide content Q CO2 Construct a valve degree control model for controlling the opening degree of the RD valve. The present invention realizes the real-time automatic adjustment of the opening degree of the RD valve to achieve a control angle matching the current smelting conditions, maximally improves the gas recovery amount, and at the same time ensures the furnace mouth draft effect, avoiding the problems of energy waste and environmental impact caused by furnace mouth smoking.

Description

Technical Field

[0001] The present invention relates to automatic control technology, and more specifically, it relates to a method for realizing automatic control of the RD valve of a purification system. Background Art

[0002] The control of the primary flue gas purification and recovery process of a converter mainly ensures that the furnace mouth is in a slightly positive pressure state through a furnace mouth differential pressure device, minimizing the occurrence of furnace mouth flaming and minimizing energy waste to the greatest extent. In the primary flue gas purification and recovery process, the "secondary venturi throat" plays a very important role, and its performance and control accuracy will directly affect the carbon monoxide recovery accuracy of the primary flue gas purification system and whether the flue gas emissions meet the standards.

[0003] According to the tracking and analysis of the primary flue gas purification and recovery system of the converter, although the use of furnace mouth differential pressure control can achieve the control of the flap opening of the "secondary venturi throat" through a hydraulic servo system, ultimately achieving the purpose of ensuring that the furnace mouth does not emit smoke and improving the quality of gas recovery, due to the influence of the on-site working conditions, the use effect is poor. Specifically, from the current use situation of the furnace mouth differential pressure device, due to the high temperature and large amount of dust at the furnace mouth position, the furnace mouth differential pressure detection device is prone to blockage and burnout, with a large amount of daily maintenance and unstable system operation. Because the system environment is extremely harsh, the use effect of the furnace mouth differential pressure control method is not ideal and cannot meet the actual use requirements. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for realizing automatic control of the RD valve of a purification system in view of the deficiencies of the prior art.

[0005] For a method for realizing automatic control of the RD valve of a purification system according to the present invention, calibrate the maximum air pressure value P in the primary dust removal purification system of the converter under the maximum emission condition 0 and the maximum exhaust gas volume Q 0 ; collect in real time the carbon monoxide content Q of the gas in the primary dust removal purification system of the converter CO , the carbon dioxide content Q CO2 and the real-time temperature T; according to the maximum air pressure value P 0 , the maximum exhaust gas volume Q 0 , the carbon monoxide content Q CO and the carbon dioxide content Q CO2 construct a valve degree control model for controlling the opening of the RD valve;

[0006] The valve degree control model is,

[0007]

[0008] wherein, K 1is the current opening of the RD valve; K 0 is the maximum opening of the RD valve; ρ CO is the density of carbon monoxide; ρ CO2 is the density of carbon dioxide; R is the proportionality constant.

[0009] The determination method for the maximum emission condition of the converter is that when the converter smelts the rated amount of hot metal, the added materials consistent with the rated amount of hot metal are input; after the added materials fully react with the hot metal and the air pressure value in the primary dust removal and purification system is within a stable range for at least 3 seconds, it is determined that the converter is in the maximum emission condition.

[0010] The ratios between the maximum and minimum values of the stable range and the average value of the maximum and minimum values are both less than or equal to 10%.

[0011] Collect the gas in the primary dust removal and purification system, specifically collect the gas in the pipeline in front of the recovery pipeline machine in the primary dust removal and purification system.

[0012] The carbon monoxide content Q CO is collected by a carbon monoxide laser analyzer.

[0013] The carbon dioxide content Q CO2 is collected by a carbon dioxide laser analyzer.

[0014] Beneficial effects

[0015] The advantages of the present invention are as follows: By interlocking the RD valve with the carbon monoxide and carbon dioxide contents in the discharged gas, according to the changes in the carbon monoxide and carbon dioxide contents during the smelting process of the converter, the real-time automatic adjustment of the opening of the RD valve is realized, so as to achieve the control angle matching the current smelting conditions, maximize the gas recovery amount, and at the same time ensure the fire-drawing effect at the furnace mouth, avoid the waste of energy and the problem of environmental impact caused by furnace mouth smoking. It not only makes up for the deficiencies of the furnace mouth differential pressure device but also realizes the goal of collecting all recoverable converter gas. Specific embodiments

[0016] The following combines embodiments to further describe the present invention, but does not constitute any limitation to the present invention. Any limited modifications made by anyone within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0017] A method for automatically controlling the RD valve of a purification system according to the present invention calibrates the maximum air pressure value P 0 and the maximum exhaust gas volume Q 0。The specific calibration method is as follows. When the converter smelts the rated amount of hot metal, add the same amount of additive materials as the rated amount of hot metal, such as ferromanganese-silicon alloy, vanadium-nitrogen alloy, and deoxidizer. When the additive materials and the hot metal fully react, the gas emission is the largest. And during this process, when the air pressure value in the primary dust removal and purification system is within a stable range for at least 3 seconds, it is determined that the converter is in the maximum emission condition. At this time, the air pressure value and the exhaust gas volume in the primary dust removal and purification system can be tested and collected, and the tested and collected air pressure value and exhaust gas volume are used as the maximum air pressure value P 0 and the maximum exhaust gas volume Q 0 。

[0018] To reduce the influence of pipeline air leakage on the test data, the method of taking the average value through multiple tests can be used to reduce the maximum air pressure value P 0 and the maximum exhaust gas volume Q 0 of the obtained data and ensure the accuracy of the data.

[0019] In addition, regarding the determination of the stable range, the present invention determines it by the percentage error range of the ratio of the extreme value to the median value. Specifically, when the ratios of the maximum value and the minimum value of the collected air pressure value to the average value of the two are both less than or equal to 10%, it indicates that the air pressure value is within a stable range at this time.

[0020] Collect the carbon monoxide content Q CO , carbon dioxide content Q CO2 and the real-time temperature T of the gas in the pipeline in front of the recovery pipeline of the primary dust removal and purification system of the converter in real time. Among them, the carbon monoxide content Q CO , carbon dioxide content Q CO2 are collected through the corresponding laser analyzers respectively. Since the collected gas is the gas in the pipeline in front of the recovery pipeline of the primary dust removal and purification system, the installation position of the laser analyzer is close to the converter mouth, and the collected gas content curve can more timely reflect the change of the smelting situation in the converter, thus creating good conditions and a foundation for the control of the RD valve.

[0021] To achieve the automatic control of the RD valve, the present invention constructs a valve opening control model according to the maximum air pressure value P 0 , maximum exhaust gas volume Q 0 carbon monoxide content Q CO and carbon dioxide content Q CO2 .

[0022] First of all, the opening of the RD valve is related to the exhaust gas volume and air pressure of the gas. Under ideal conditions, Therefore, whether using the exhaust gas volume ratio or the air pressure ratio, the opening ratio of discharging the corresponding gas can be determined.

[0023] The above-mentioned P1 is the current exhaust gas pressure value, which can be obtained by collecting through a gas pressure sensor. Q 1 is the current total exhaust volume, which can be obtained according to the ratio formula obtained. P CO and P CO2 can both be obtained through the relationship formula of the pressure, volume and density of the gas. For example, where ρ CO is the density of carbon monoxide; ρ CO2 is the density of carbon dioxide; R is a proportional constant.

[0024] However, due to the problem of pipeline air leakage, P 1 is often on the small side. That is Therefore, the required opening degree in real time is also reduced.

[0025] For this reason, the present invention introduces a compensation value to solve this problem and achieve the purpose of reducing errors and increasing the opening degree accuracy.

[0026] Specifically, the relevant compensation value for carbon monoxide gas is: The relevant compensation value for carbon dioxide gas is:

[0027] After introducing the compensation value, the opening degree ratios of the discharged carbon monoxide and carbon dioxide are respectively:

[0028]

[0029] The gas discharged from the converter mainly consists of carbon monoxide, followed by carbon dioxide, and the sum of the remaining gases is equivalent to the amount of carbon dioxide. Therefore, the opening degree ratios of all gases in the present invention are:

[0030]

[0031] According to the above formula, a valve degree control model can be constructed as:

[0032]

[0033] where K 1 is the current opening degree of the RD valve; K 0 is the maximum opening degree of the RD valve.

[0034] The above are only the preferred embodiments of the present invention. It should be noted that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which will not affect the implementation effect of the present invention and the practicability of the patent.

Claims

1. A method for automatically controlling the RD valve of a purification system, characterized in that, Calibrate the maximum air pressure value P in the primary dust removal and purification system of the converter under the maximum emission condition 0 and the maximum exhaust volume ; Real-time collect the carbon monoxide content , carbon dioxide content and the real-time temperature T of the gas in the primary dust removal and purification system of the converter; According to the maximum air pressure value P 0 , maximum exhaust volume , carbon monoxide content and carbon dioxide content Construct a valve control model for controlling the opening of the RD valve; the valve opening control model is, Among them, K 1 is the current opening of the RD valve; K 0 is the maximum opening of the RD valve; ρ CO is the density of carbon monoxide; ρ CO2 is the density of carbon dioxide; R is the proportional constant; the determination method for the maximum emission condition of the converter is as follows: when the converter smelts molten iron at the rated amount, add the same amount of additive materials as the rated amount of molten iron; wait until the additive materials and the molten iron react fully, and the air pressure value in the primary dust removal purification system is within a stable range for at least 3 seconds, then determine that the converter is in the maximum emission condition.

2. A method for automatically controlling the RD valve of a purification system according to claim 1, characterized in that, the ratio between the maximum value and the minimum value of the stable range and the average value of the maximum value and the minimum value is less than or equal to 10%.

3. A method for automatically controlling the RD valve of a purification system according to any one of claims 1-2, characterized in that, collect the gas in the primary dust removal purification system, specifically collect the gas in the pipeline in front of the recovery pipeline machine in the primary dust removal purification system.

4. A method for automatically controlling the RD valve of a purification system according to claim 3, characterized in that, The carbon monoxide content is collected by a carbon monoxide laser analyzer.

5. A method for automatically controlling the RD valve of a purification system according to claim 3, characterized in that, The carbon dioxide content is collected by a carbon dioxide laser analyzer.

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