Anti-surge dynamic adjusting method for blast furnace blower

Abstract

The anti-surge dynamic adjustment method for the blast furnace blower comprises the following steps: carrying out a surge test, obtaining surge point data under different stationary blade angles, and establishing an initial surge line; performing temperature compensation on the initial surge line to obtain a dynamic surge line changing along with the inlet temperature; based on the dynamic surge line, determining a dynamic anti-surge adjusting line; operating parameters of the fan are collected in real time, and the deviation and the deviation change rate of the working condition point and the anti-surge adjusting line are calculated; and according to the deviation and the deviation change rate, the opening degree of the anti-surge valve is dynamically adjusted, and quick opening and slow closing control over the anti-surge valve is achieved. According to the method, a real-time fan surge curve and an anti-surge adjusting line can be provided along with seasonal temperature changes, the change trend of the working condition of the fan is collected, analyzed and predicted, anti-surge control output is dynamically adjusted, the operation space of the fan is enlarged, the capability of preventing the dangerous surge working condition of the blast furnace fan is improved, pressure fluctuation is stabilized while the fan is protected, and the service life of the fan is prolonged. And the ventilation amount is reduced and the loss is reduced.

Description

Technical Field

[0001] This invention relates to the field of blast furnace blower control technology, and more particularly to the field of dynamic adjustment technology for blast furnace blower anti-surge. Background Technology

[0002] In steel enterprises, blast furnace blower units play a crucial role, serving as the main power equipment to ensure the stable and smooth operation of blast furnace production. The operation of a blast furnace requires a stable air volume to maintain the combustion process and the state of the furnace charge, ensuring stable furnace temperature and gas flow. Fluctuations in air volume directly affect the charging speed, thus impacting the thermal balance of the hearth and reducing daily iron production. Surge failures during blower operation can lead to serious accidents such as slag charging in the blast furnace, and sometimes even equipment damage, resulting in significant economic losses. The surge performance curve of the blower changes with seasonal temperature variations; using a fixed surge performance curve cannot accurately reflect the blower's surge performance. This may affect the safe and stable operation of the blower and limit its full utilization of air supply capacity.

[0003] Therefore, dynamic compensation is needed for the blower surge performance curve to obtain a movable surge line and an anti-surge adjustment line that vary with seasonal temperatures, accurately reflecting the blower's performance under different conditions. By dynamically controlling the stator blade angle and anti-surge valve along the accurate anti-surge line, the blower can operate close to the anti-surge line, preventing surge and maximizing its efficiency. This ensures the blower operates safely and efficiently while meeting the blast furnace's air volume and pressure requirements.

[0004] A novelty search revealed several relevant documents and patents, such as CN109458355B, which discloses a method for controlling surge in a compressor. This invention establishes a pressure difference offset function between the compressor's inlet temperature and flow rate, and calculates the pressure difference offset of the compressor's flow rate based on this function. The compressor is controlled to prevent surge based on the anti-surge control line expressed as the pressure difference between the inlet and outlet pressure ratio and the flow rate, along with the pressure difference offset X. This makes the anti-surge control of the compressor more precise and prevents energy waste caused by frequent venting of the anti-surge valve. The problem with this method is that when process fluctuations or disturbances cause the compressor's operating state to shift rapidly towards surge, the anti-surge control response is relatively slow, resulting in the anti-surge valve opening too wide and for too long.

[0005] CN116104781A discloses a control system and control method for a fan. The fan control system provided by this invention includes a first control valve and a control device. The first control valve is located in a first bypass pipeline. The control device is configured to acquire the fan's operating status information, determine whether the fan is experiencing surge based on the operating status information, and control the first control valve when surge occurs. By controlling the first bypass pipeline to assist the exhaust pipeline in venting, the control system increases the overall flow rate of the fan, allowing the fan flow rate to automatically return to its normal range, thus avoiding the problem of fan surge and providing good protection for the fan. In actual operation, the fan's operating temperature often exceeds or falls below its design operating temperature. Its surge curve changes due to the ambient temperature, making the original surge curve inaccurate. As a result, the control valve in this invention frequently vents, leading to energy waste.

[0006] CN110067766A discloses a method for anti-surge safety adjustment and protection of blast furnace axial flow fans. This invention collects real-time data from the fan's operating points to form fan surge test data, which is then input and saved to a controller, with a predetermined safety threshold to form an anti-surge curve. The actual operating point of the fan and the anti-surge curve are calculated and compared. When the difference between the fan exhaust pressure value corresponding to the operating point and the anti-surge curve is less than 20 kPa, the anti-surge control system controls the opening of the anti-surge valve to keep the actual operating point of the fan away from the surge line, and simultaneously triggers a visual alarm. This ensures the safe operation of the fan while protecting the blast furnace. However, this invention does not consider the rate of change of the axial flow fan's operating parameters to alter the control target of the compressor's anti-surge control, and the fan cannot make a dynamic adjustment response in advance.

[0007] In summary, because the surge performance curve of the blower changes with seasonal temperature variations, an inaccurate surge curve prevents the blower from making timely dynamic adjustments. This results in frequent venting of the anti-surge valve, leading to energy waste and impacting the safe operation of the blast furnace. Therefore, it is essential to explore a more effective dynamic adjustment method for blast furnace blower anti-surge, expanding the blower's operating range, reducing venting volume, lowering energy consumption, protecting the blower, stabilizing pressure fluctuations, and ensuring smooth blast furnace smelting operations. Summary of the Invention

[0008] This invention proposes a dynamic adjustment method for anti-surge of blast furnace blowers. This method can provide real-time blower surge curves and anti-surge adjustment lines according to seasonal temperature changes. It can collect, analyze, and predict the trend of blower operating conditions, dynamically adjust the anti-surge control output, increase the blower's operating space, improve the ability to prevent dangerous surge conditions of blast furnace blowers, stabilize pressure fluctuations while protecting the blower, reduce venting volume, reduce losses, and better serve blast furnace smelting.

[0009] To achieve the above objectives, the present invention employs the following technical solution: A dynamic adjustment method for preventing surge in a blast furnace blower, specifically including the following steps: S1. Wind turbine surge performance test: Establish a two-dimensional coordinate system and determine the initial surge line. Specifically, this includes: S11. Close the blast furnace blower's air supply valve and open the blower's anti-surge valve. At the blower's rated speed, select three stationary blade angles within the range of 22° to 79° at intervals of 8° to 15° to conduct surge tests sequentially. Repeat the test process for different stationary blade angles and record the throat differential pressure and exhaust pressure at each surge point.

[0010] S12. Using the throat differential pressure as the X-axis and the exhaust pressure as the Y-axis, determine these points in the coordinate system and connect them to obtain the initial surge line of the fan.

[0011] S2. Establish a dynamic compensation model to calculate the differential pressure at the fan throat and the exhaust pressure after temperature compensation. Specifically, this includes: S21. Based on the surge performance test of the fan, temperature compensation is performed on the entire surge line. The inlet temperature of the axial flow fan is... Become The inlet pressure of the blower is Calculate the exhaust pressure of the fan after temperature compensation. (1); In formula (1) —Isentropic index 1.4; —The inlet temperature of the fan is Actual exhaust pressure was measured at the time.

[0012] S22. Temperature compensation is also performed on the differential pressure at the fan inlet throat; the inlet temperature is... Become At that time, the differential pressure at the fan inlet throat after temperature compensation is: (2); In formula (2) —Temperature-compensated laryngeal pressure differential; —Differential pressure at the throat of the fan.

[0013] S3, laryngeal differential pressure after temperature compensation and exhaust pressure The x and y axes are used as the horizontal and vertical axes of the wind turbine surge performance curve, respectively, to correct the surge line and determine the dynamic surge curve that varies with temperature.

[0014] S4. Based on the dynamic surge curve, determine the dynamic anti-surge adjustment line for the wind turbine. Specifically, this includes: S41. Based on the dynamic surge line, the vertical axis of the surge line remains unchanged, and the horizontal axis is multiplied by a margin coefficient in the range of 1.12 to 1.22 to obtain three sets of fan throat differential pressure and exhaust pressure data. , ), ( , ), ( , ).

[0015] S42. Using the three sets of differential pressure at the fan throat and exhaust pressure data, determine other coordinate points in the coordinate system. , ; , ; , .connect( , ), ( , ), ( , ), ( , () , The anti-surge adjustment curve is obtained by plotting the curve.

[0016] S5. Collect, analyze, and predict the changing trends of the wind turbine's operating points, and adjust the anti-surge control output according to the anti-surge dynamic adjustment and control model. Specifically, this includes: S51 compares the measured differential pressure at the fan throat and the outlet exhaust pressure with the parameters of the anti-surge adjustment curve after temperature compensation to determine the upper limit value SP of the exhaust pressure at the corresponding operating point. It then performs an over-limit judgment, using the converted exhaust pressure value as the collected value PV. If PV < SP, the fan is operating in the stable zone, the automatic output value of the anti-surge valve is 100%, and the anti-surge valve is fully closed. If PV > SP, variable gain is calculated based on the positive and negative deviation and the rate of change of the difference between the upper limit value SP and the collected value PV. (3); In equation (3), ; —The absolute value of the deviation; —Differential time; —An adjustable constant; —Variable gain; —Rate of deviation change. The greater the rate of increase in the operating point, the greater the rate of deviation change, and the greater the variable gain. The larger the value.

[0017] S52 establishes a dynamic adjustment and control model for anti-surge based on variable gain, as follows: (4); In formula (4) The time for integration.

[0018] The anti-surge dynamic adjustment and control model responds simultaneously to the deviation and the rate of change of the deviation at the operating point. It dynamically adjusts the opening of the anti-surge valve from two dimensions: speed and amplitude. This allows a portion of the blower's outlet flow to be released in the form of venting, changing the characteristics of the pipeline network and enabling the blower system to quickly transition from an unstable operating condition to a stable operating condition.

[0019] Compared with the prior art, the beneficial effects of the present invention are: This invention provides a dynamic adjustment method for anti-surge of a blast furnace blower. Based on blower surge performance testing, this method performs real-time dynamic compensation on the surge line, providing precise blower surge and anti-surge adjustment lines. It collects, analyzes, and predicts operating condition changes, dynamically adjusts the anti-surge control output, and combines fast and slow adjustment responses to ensure the blower's operating point operates close to the anti-surge line, avoiding adjustment oscillations and maximizing blower efficiency. This ensures safe and efficient blower operation while meeting the blast furnace's air volume and pressure requirements. Attached Figure Description

[0020] Figure 1 This is a flowchart of the dynamic adjustment method for preventing surge in blast furnace blowers according to the present invention.

[0021] Figure 2 This is a comparison of the blower anti-surge adjustment curves under different intake temperatures in the embodiments. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the specific implementation methods of this invention will be further described below in conjunction with the embodiments. The following embodiments are used to specifically illustrate the content of this invention. These embodiments are only general descriptions of the content of this invention and do not limit the content of this invention.

[0023] A dynamic adjustment method for preventing surge in a blast furnace blower, specifically including the following steps: 1) Close the blast furnace blower's air supply valve and fully open the blower's anti-surge valve and vent valve. After the blower reaches its rated speed, conduct surge tests sequentially at three stator blade angles within the range of 22°~79°, at intervals of 8°~15°. When the stator blades are adjusted to the specified angle, gradually close the anti-surge valve to build up pressure. Closely monitor the real-time changes of important parameters such as exhaust pressure, air volume, throat pressure difference, and air temperature, continuously closing the valve until the blower reaches the surge critical point. Then, quickly open the anti-surge valve to protect the unit's safety. At each stator blade angle, record the throat pressure difference and exhaust pressure when the blower reaches the surge critical point. After obtaining three sets of data, determine these points in the coordinate system, using the throat pressure difference as the X-axis and the exhaust pressure as the Y-axis. Connecting these points yields the initial surge line of the blower, which serves as the basis for anti-surge control calculations.

[0024] 2) Based on the surge performance test of the fan, temperature compensation is performed on the entire surge line to ensure that the performance of the surge line and the fan under different conditions accurately corresponds. This is based on the relationship between inlet flow rate and throat differential pressure. , For flow coefficient, This refers to the differential pressure at the throat of the fan. This refers to the inlet temperature of the fan. At the same flow rate... Below, the inlet temperature is from Become At that time, the compensation for the differential pressure in the larynx is , This is the throat differential pressure after temperature compensation. At the same flow rate... Below, the inlet temperature of the axial flow fan is reduced from... Become Treating it as an adiabatic process, analyze the impact of inlet temperature changes on outlet pressure, considering the inlet temperature of the axial flow fan as... Become Given that the compression energy head remains constant, the inlet temperature is calculated as follows: The pressure ratio at that time, the inlet pressure of the blower is The compensated exhaust pressure of the fan was obtained. ; (1); In formula (1) —Isentropic index 1.4; —The inlet temperature of the fan is Actual exhaust pressure was measured at the time.

[0025] Temperature compensation is also applied to the differential pressure at the fan inlet throat, with the inlet temperature adjusted accordingly. Become At that time, the compensation formula for the differential pressure in the larynx is: (2); In formula (2) —Throat differential pressure after inlet temperature compensation; —Differential pressure at the throat of the fan.

[0026] The throat differential pressure and outlet exhaust pressure after temperature compensation are calculated according to equations (1) and (2), respectively. These points are determined in the coordinate system, connected to form a curve, and the dynamic surge line of the fan after temperature compensation is established.

[0027] 3) Based on temperature compensation, the dynamic surge line is obtained by multiplying the vertical axis of the surge line by a margin coefficient in the range of 1.12 to 1.22, resulting in three sets of data on the differential pressure at the fan throat and the exhaust pressure. , ), ( , ), ( , Using three sets of differential pressure data at the fan throat and exhaust pressure data, other coordinate points are determined in the coordinate system. , ; , ; , .connect( , ), ( , ), ( , ), ( , () , The surge curve is obtained by plotting the surge curve. This curve more accurately reflects the equipment performance, ensuring the accuracy of the surge line and the anti-surge adjustment line under different climatic conditions, and fully utilizing the fan's air supply capacity while ensuring safe operation.

[0028] 4) Process the data collected on-site. Based on the anti-surge adjustment curve, derive the upper limit value SP of the exhaust pressure at the corresponding actual operating point. Determine if the operating point exceeds the limit. The converted exhaust pressure value is used as the collected value PV. If PV < SP, the blower is operating in the stable zone. Adjust the blower's stator angle in real time to meet the blast furnace's air demand. The anti-surge valve remains closed and does not activate. If PV > SP, perform differential calculations on the deviation signal between the blast furnace blower's operating point and the anti-surge line. , , The differential time is used to detect the speed of the blower at its actual operating point.

[0029] Based on the positive and negative deviations and the rate of change of the difference between the upper limit value SP and the collected value PV. Perform variable gain calculation. (3); In equation (3), ; —The absolute value of the deviation; —Differential time; —An adjustable constant; —Variable gain; —Rate of deviation change. The greater the rate of increase in the operating point, the greater the rate of deviation change, and the greater the variable gain. The larger the value.

[0030] A dynamic adjustment and control model for anti-surge is established based on variable gain, as follows: (4); In formula (4) The time for integration.

[0031] When the wind turbine is detected to be approaching surge condition, the control system dynamically adjusts the opening of the anti-surge valve in real time according to the magnitude and speed of the shift in the operating point. The anti-surge dynamic adjustment control model ensures that the anti-surge valve can act quickly when the wind turbine operating point crosses the adjustment line, so that the wind turbine operating point can quickly return from the unstable area to the stable operating area, thereby improving the dynamic response speed and reliability of the anti-surge control.

[0032] The measured data of the surge point of the blast furnace blower in the embodiments of the present invention are shown in Table 1; the calculated results of the surge point parameters of the blower after temperature compensation in the embodiments are shown in Table 2; and the calculated results of the anti-surge adjustment curve data of the blower in the embodiments are shown in Table 3.

[0033] Table 1. Measured data on surge point of blast furnace blower. Operating point 1 2 3 still blade angle / ° 25 33 42 Measured differential pressure in the larynx (kPa) 1.9 3.0 4.0 Measured exhaust pressure / kPa 318 410 488 Inlet air temperature / °C 25 25 25 Table 2. Calculation results of blower surge point parameters after temperature compensation. Operating point 1 2 3 still blade angle / ° 25 33 42 Laryngeal differential pressure / kPa 2.0 3.2 4.3 Exhaust pressure / kPa 355 460 550 Inlet air temperature / °C 0 0 0 Table 3. Calculation results of blower anti-surge adjustment curve data. Laryngeal differential pressure / kPa 1.2 2.4 3.2 3.9 4.6 5.2 Exhaust pressure / kPa 178 355 408 460 505 550 Inlet air temperature / °C 0 0 0 0 0 0

[0034] This invention eliminates the surge hazard caused by the deviation of the blast furnace blower's operating point from both speed and amplitude dimensions, improving the reliability of anti-surge control. When the operating point rapidly crosses the anti-surge adjustment line, the further the operating point exceeds the line, the faster the control action, achieving rapid opening of the anti-surge valve and faster exit of the operating point from the surge region. When the operating point returns to the stable operating region, the deviation 'e' decreases, the proportional gain decreases, the integral time increases, and the response speed slows down, achieving slow closing of the anti-surge valve and avoiding oscillating surge phenomena caused by excessively rapid closure of the anti-surge valve. This ensures both good speed of anti-surge valve action when the operating point crosses the control line and stable system regulation when the operating point approaches the control line.

Claims

1. A dynamic surge prevention method for a blast furnace blower, characterized by, include: S1. Wind turbine surge performance test: Establish a two-dimensional coordinate system and determine the initial surge line; S2. Establish a dynamic compensation model and calculate the differential pressure at the fan throat and the exhaust pressure after temperature compensation. S3, throat differential pressure after temperature compensation and exhaust pressure , as the horizontal and vertical coordinates of the fan surge performance curve, respectively, correct the surge line, and determine the dynamic surge curve that changes with temperature; S4. Based on the dynamic surge curve, determine the dynamic anti-surge adjustment line of the fan; S5. Collect, analyze, and predict the changing trends of the wind turbine's operating points, and adjust the anti-surge control output according to the anti-surge dynamic adjustment and control model.

2. A dynamic surge prevention regulating method for a blast furnace blower according to claim 1, characterized in that, Step S1 specifically includes: S11. Close the blast furnace blower air supply valve, open the blower anti-surge valve, and at the blower rated speed, select three stationary blade angles in the range of 22°~79° at intervals of 8°~15° to conduct surge tests in sequence; repeat the test process for different stationary blade angles, and record the throat differential pressure and exhaust pressure at each surge point; S12. Using the throat differential pressure as the X-axis and the exhaust pressure as the Y-axis, determine these points in the coordinate system and connect them to obtain the initial surge line of the fan.

3. A dynamic surge prevention regulating method for a blast furnace blower according to claim 1, characterized in that, Step S2 specifically includes: S21, based on the fan surge performance test, the temperature compensation is carried out on the whole surge line, the inlet temperature of the axial flow fan is changed from to , the fan inlet pressure is , and the exhaust pressure of the fan after temperature compensation is calculated （1）； In formula (1) - isentropic exponent 1.4; - fan inlet temperature is Actual measured exhaust pressure when S22, the fan inlet throat differential pressure is also temperature compensated, the inlet temperature is from becomes When the temperature compensation of the fan inlet throat differential pressure is performed, the temperature compensated fan inlet throat differential pressure is: （2）； In formula (2) — throat differential pressure after temperature compensation — fan throat differential pressure 4. A dynamic surge prevention regulating method for a blast furnace blower according to claim 1, characterized by, Step S4 specifically includes: S41, on the basis of the dynamic surge line, the surge line ordinate is unchanged, the abscissa is multiplied by a margin coefficient in the range of 1.12~1.22, to obtain three groups of fan throat differential pressure, exhaust pressure data , )、( , )、( , ​ S42. Using the three sets of differential pressure at the fan throat and exhaust pressure data, determine other coordinate points in the coordinate system. , ; , ; , .connect( , ), ( , ), ( , ), ( , () , The anti-surge adjustment curve is obtained by plotting the curve.

5. The dynamic adjustment method for anti-surge of a blast furnace blower according to claim 1, characterized in that, Step S5 specifically includes: S51 compares the measured differential pressure at the fan throat and the outlet exhaust pressure with the parameters of the anti-surge adjustment curve after temperature compensation to determine the upper limit value SP of the exhaust pressure at the corresponding operating point. It then performs an over-limit judgment, using the converted exhaust pressure value as the collected value PV. If PV < SP, the fan is operating in the stable zone, the automatic output value of the anti-surge valve is 100%, and the anti-surge valve is fully closed. If PV > SP, variable gain is calculated based on the positive and negative deviation and the rate of change of the difference between the upper limit value SP and the collected value PV. （3）； In equation (3), ; —The absolute value of the deviation; —Differential time; —Rate of change of deviation; —An adjustable constant; —Variable gain; the greater the rate of increase in the operating point, the greater the rate of change in deviation, and the greater the variable gain. The larger the value; S52 establishes a dynamic adjustment and control model for anti-surge based on variable gain, as follows: （4）； In formula (4) The time for integration.

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