Converter gas cooling control system

Abstract

The application provides a converter gas cooling control system, and belongs to the technical field of steel metallurgy automation control. The system comprises: a temperature detection module for obtaining the gas temperature at the outlet of a gas cooler; a temperature comparison module for comparing the gas temperature with a target temperature control range; and a cooling control module for controlling the flow of the cooling medium of the gas cooler according to the comparison result; wherein if the gas temperature is lower than the lower limit value of the target temperature control range, the flow of the cooling medium is reduced; if the gas temperature is higher than the upper limit value of the target temperature control range, the flow of the cooling medium is increased; and if the gas temperature belongs to the target temperature control range, the current flow of the cooling medium is kept unchanged. The application can automatically compare the gas temperature and dynamically adjust the flow of the cooling medium, reduce excessive cooling energy consumption, and improve the utilization efficiency of the gas.

Description

Technical Field

[0001] This application relates to the field of automation control technology in iron and steel metallurgy, and in particular to a converter gas cooling control system. Background Technology

[0002] Converter gas is an important secondary energy source in steelmaking, and the gas cooler is a key piece of equipment in its recovery system, used to cool and dehydrate the high-temperature gas. Existing converter gas cooling systems typically use temperature sensors to detect the gas temperature at the cooler outlet, displaying the value in the control room or issuing an over-limit alarm. Based on this temperature reading, operators manually adjust the opening of the circulating water pump outlet valve or the number of pumps started and stopped, relying on experience, to roughly change the cooling water flow rate in an attempt to control the gas temperature within the equipment's safe range (generally 40-50℃).

[0003] This detection and control method, which relies on manual intervention, has significant technical flaws: First, the detection and execution processes are disconnected, resulting in large fluctuations in converter gas flow and temperature, and a severe lag in manual adjustment response, making timely tracking impossible. Second, the system lacks the logic to automatically compare and control the flow using the detected temperature as feedback, causing the gas cooler to remain in an "overcooled" state for extended periods. Excessive cooling not only consumes excessive circulating water and electricity but also increases the moisture content of the gas, reducing its effective calorific value utilization rate. Summary of the Invention

[0004] This application provides a converter gas cooling control system to solve the problems of response lag and lack of closed-loop flow control caused by manual intervention in the prior art. It aims to achieve the purpose of automatically comparing and dynamically adjusting the cooling medium flow rate according to the gas temperature, reducing excessive cooling energy consumption and improving gas utilization efficiency.

[0005] This application provides a converter gas cooling control system, including: The temperature detection module is used to obtain the gas temperature at the outlet of the gas cooler; The temperature comparison module is used to compare the gas temperature with the target temperature control range; The cooling control module is used to control the flow rate of the cooling medium in the gas cooler based on the comparison results. Specifically, if the gas temperature is lower than the lower limit of the target temperature control range, the flow rate of the cooling medium is reduced; if the gas temperature is higher than the upper limit of the target temperature control range, the flow rate of the cooling medium is increased; if the gas temperature is within the target temperature control range, the current flow rate of the cooling medium is kept unchanged.

[0006] In one exemplary embodiment of this application, the cooling medium inlet of the gas cooler is connected to the outlet of the circulating water pump, the cooling medium outlet of the gas cooler is connected to one end of the cooling medium return pipe, and the other end of the cooling medium return pipe is connected to the inlet of the circulating water pump. The cooling control module includes a return regulating unit and a water pump regulating unit, wherein... The reflux regulating unit is used to adjust the opening of the reflux regulating valve installed on the cooling medium reflux pipe to control the flow rate of the cooling medium. When the gas temperature is lower than the lower limit of the target temperature control range, the opening of the reflux regulating valve is increased until the reflux regulating valve reaches the fully open state; when the gas temperature is higher than the upper limit of the target temperature control range, the opening of the reflux regulating valve is decreased until the reflux regulating valve reaches the fully closed state. The water pump regulating unit is used to adjust the operating frequency of the circulating water pump to control the flow rate of the cooling medium. If the return regulating valve is fully open or fully closed, and the gas temperature is still not within the target temperature control range, the frequency of the circulating water pump is reduced or increased through the water pump regulating unit.

[0007] In one exemplary embodiment of this application, the cooling control module is further configured to: During the process of adjusting the opening of the reflux control valve, if the gas temperature is within the target temperature control range and continues to exceed the first preset time, the current opening of the reflux control valve will be used as the reference opening. Wait for the second preset time. If the gas temperature is not within the target temperature control range and the deviation between the gas temperature and the target temperature control range is less than the preset deviation threshold, then based on the reference opening and by adjusting the opening of the reflux regulating valve through the preset step size, continue to wait for the second preset time. If the gas temperature is within the target temperature control range, then keep the current flow rate of the cooling medium unchanged. If the gas temperature is not within the target temperature control range, the opening of the reflux regulating valve is adjusted by a preset step size until the gas temperature is within the target temperature control range, or if the gas temperature is still not within the target temperature control range after a preset number of times, the water pump regulating unit is triggered to adjust the frequency.

[0008] In one exemplary embodiment of this application, a bypass valve is provided at the outlet of the circulating water pump. The cooling control module is also used to control the opening of the reflux regulating valve according to the gas temperature, and to control the circulating water pump to operate at a preset flow rate through the bypass valve.

[0009] In one exemplary embodiment of this application, the cooling control module further includes a frequency protection unit. The frequency protection unit is used to generate an alarm signal when the frequency of the circulating water pump drops to the preset minimum safe frequency. When the gas temperature is still below the lower limit of the target temperature control range, the bypass valve is triggered to open or the shutdown protection action is triggered.

[0010] In one exemplary embodiment of this application, the system further includes a monitoring and evaluation module. The monitoring and evaluation module is used to monitor the temperature and instantaneous flow rate of the cooling medium and obtain monitoring data. Historical trend records are determined based on monitoring data and gas temperature. The effectiveness of the cooling control module is evaluated based on historical trend records.

[0011] In one exemplary embodiment of this application, the monitoring and evaluation module is further configured to: The change in gas moisture content is determined based on the correlation between gas temperature and saturated moisture content. The increase in the effective calorific value of coal gas is assessed based on changes in the moisture content of the coal gas.

[0012] In one exemplary embodiment of this application, the monitoring and evaluation module is further configured to: The control precision of the gas temperature is determined based on the gas temperature. The results of the power consumption adjustment of the control system are evaluated by analyzing the deviation between the control accuracy and the target temperature control range, as well as the relationship between the power consumption change of the circulating water pump and the flow rate of the cooling medium.

[0013] In one exemplary embodiment of this application, the cooling control module further includes a feedforward adjustment unit. The feedforward control unit is used to obtain the rate of change of gas temperature. When the rate of change is higher than the preset rate of change threshold, the control signal is output to the reflux control unit or the water pump control unit to pre-adjust the flow rate of the cooling medium.

[0014] In one exemplary embodiment of this application, the target temperature control range is 60°C-70°C.

[0015] The beneficial effects of the converter gas cooling control system provided in this application embodiment are as follows: This embodiment acquires the outlet temperature of the gas cooler in real time through a temperature detection module, and automatically compares it with the target temperature control range through a temperature comparison module. The cooling control module then directly adjusts the cooling medium flow rate based on the comparison result. This embodiment solves the problem of loose connection between detection and execution, enabling real-time and continuous response to drastic fluctuations in converter gas flow rate and temperature, eliminating the severe lag of manual adjustment. Through precise range comparison and flow rate adjustment, this embodiment avoids blindly over-cooling to prevent overheating, reducing the moisture content in the gas and thus improving the effective calorific value utilization rate of the converter gas. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the converter gas cooling control system provided in the embodiments of this application; Figure 2 This is a schematic diagram of the cooling control module of the gas cooler provided in the embodiments of this application. Detailed Implementation

[0018] To enable those skilled in the art to better understand this solution, the technical solutions in the embodiments of this solution will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this solution, not all of them. Based on the embodiments of this solution, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this solution.

[0019] The term "comprising" and any other variations thereof in the specification, claims, and accompanying drawings of this invention mean "including but not limited to," and are intended to cover a non-exclusive inclusion, not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish different objects, not to describe a specific order.

[0020] The implementation of this application will be described in detail below with reference to the specific accompanying drawings: Figure 1 This is a schematic diagram of a converter gas cooling control system provided in an embodiment of this application. (Refer to...) Figure 1 The converter gas cooling control system includes a temperature detection module 11, a temperature comparison module 12, and a cooling control module 13.

[0021] Among them, the temperature detection module 11 is used to obtain the gas temperature at the outlet of the gas cooler; Temperature comparison module 12 is used to compare the gas temperature with the target temperature control range; The cooling control module 13 is used to control the flow rate of the cooling medium in the gas cooler based on the comparison results. If the gas temperature is lower than the lower limit of the target temperature control range, the flow rate of the cooling medium is reduced; if the gas temperature is higher than the upper limit of the target temperature control range, the flow rate of the cooling medium is increased; if the gas temperature is within the target temperature control range, the current flow rate of the cooling medium is kept unchanged.

[0022] In this embodiment, the control system is initialized and the target temperature control range of the temperature comparison module 12 is set to 60℃-70℃.

[0023] After the control system is started, the temperature detection module 11 continuously and in real time acquires the gas temperature at the outlet of the gas cooler and sends the gas temperature to the temperature comparison module 12.

[0024] The temperature comparison module 12 compares the gas temperature with the target temperature control range (60℃-70℃), outputs the comparison result, and transmits the result to the cooling control module 13. In this embodiment, the comparison result may include any of the following: Result A: The gas temperature is less than the lower limit of the target range (i.e., less than 60℃); Result B: The gas temperature is within the target range (i.e., the gas temperature is not less than the lower limit of the target range and the gas temperature is not greater than the upper limit of the target temperature). Result C: The real-time gas temperature is greater than the upper limit of the target range (i.e., greater than 70℃).

[0025] In this embodiment, the cooling control module 13 automatically and dynamically adjusts the flow rate of the cooling medium entering the gas cooler based on the comparison results. In this embodiment, the cooling medium is cooling water.

[0026] The adjustment method is as follows: If the comparison result is result A, and the detected gas temperature is below 60℃, it is automatically determined that the current state is "overcooled". At this time, the cooling control module 13 issues a first adjustment command to reduce the flow rate of circulating water entering the gas cooler, thereby allowing the gas temperature to rise back to the target range. Specifically, reducing the flow rate of circulating water entering the gas cooler can be achieved by closing the cooling water inlet regulating valve or reducing the operating frequency of the circulating water pump.

[0027] If the comparison result is result B, and the detected gas temperature is within the range of 60℃-70℃, then it is determined that the current cooling effect meets the requirements. At this time, the cooling control module 13 does not issue an adjustment command, keeps the current cooling water flow unchanged, and maintains the stable operation of the system.

[0028] If the comparison result is result C, indicating that the gas temperature is above 70℃, it is determined that the gas is currently in an "overheated" state with insufficient cooling capacity. In this case, the cooling control module 13 issues a second adjustment command to increase the flow rate of circulating water entering the gas cooler, thereby enhancing the cooling effect and lowering the gas temperature to the target range. Specifically, increasing the flow rate of circulating water entering the gas cooler can be achieved by opening the cooling water inlet regulating valve or by increasing the operating frequency of the circulating water pump.

[0029] As can be seen from the above, this embodiment, by precisely controlling the temperature within the target range of 60-70℃, avoids process fluctuations caused by over-cooling or under-cooling, thus enhancing the stability of the control system. This embodiment also controls the gas temperature to increase the cooling water flow only when it exceeds the target range, reducing the power consumption of the circulating water pump and the loss of circulating water.

[0030] In one embodiment of this application, the cooling medium inlet of the gas cooler is connected to the outlet of the circulating water pump, the cooling medium outlet of the gas cooler is connected to one end of the cooling medium return pipe, and the other end of the cooling medium return pipe is connected to the inlet of the circulating water pump. The cooling control module includes a return regulating unit and a water pump regulating unit. The reflux regulating unit is used to adjust the opening of the reflux regulating valve installed on the cooling medium reflux pipe to control the flow rate of the cooling medium. When the gas temperature is lower than the lower limit of the target temperature control range, the opening of the reflux regulating valve is increased until the reflux regulating valve reaches the fully open state; when the gas temperature is higher than the upper limit of the target temperature control range, the opening of the reflux regulating valve is decreased until the reflux regulating valve reaches the fully closed state. The water pump regulating unit is used to adjust the operating frequency of the circulating water pump to control the flow rate of the cooling medium. If the return regulating valve is fully open or fully closed, and the gas temperature is still not within the target temperature control range, the frequency of the circulating water pump is reduced or increased through the water pump regulating unit.

[0031] In this embodiment, after obtaining the comparison result from the temperature comparison module 12, the cooling control module 13 fine-tunes the reflux regulating unit based on the comparison result and a preset priority call strategy. Specifically, when the gas temperature is below 60°C (overcooled), a third regulation command is issued through the reflux regulating unit to increase the opening of the reflux regulating valve. In this embodiment, increasing the opening of the reflux regulating valve indicates that more cooling water returns directly through the reflux pipe, reducing the effective water volume entering the gas cooler, and causing the gas temperature to rise accordingly. The opening of the reflux regulating valve is continuously increased until any of the following conditions are met: Once the gas temperature returns to the 60℃-70℃ range, stop adjusting and maintain the current reflux valve opening. The reflux regulating valve is fully open (100% opening), but the gas temperature is still below 60℃. At this point, the reflux regulating capacity has reached its limit, and coarse adjustment will be made through the water pump regulating unit.

[0032] In this embodiment, when the gas temperature exceeds 70°C (overheated), a fourth regulation command is issued through the reflux regulation unit to reduce the opening of the reflux regulation valve. In this embodiment, a reduced opening of the reflux regulation valve indicates a decrease in the amount of cooling water flowing back, allowing more cooling water to enter the gas cooler, enhancing the cooling effect, and lowering the gas temperature. The opening of the reflux regulation valve is continuously reduced until any of the following conditions are met: The gas temperature has returned to the 60℃-70℃ range. At this point, stop adjusting and maintain the current reflux valve opening. The reflux regulating valve is fully closed (0% opening), but the gas temperature is still above 70°C. At this point, the reflux regulating capacity has reached its limit, and coarse adjustment will be made through the water pump regulating unit.

[0033] In this embodiment, when the gas temperature is within the range of 60℃-70℃, there is no need to adjust the opening of the reflux control valve; simply maintain the current reflux valve opening.

[0034] In this embodiment, if the reflux regulation fails to adjust the gas temperature to the target temperature control range, the system automatically switches to the water pump regulation unit for coarse adjustment. The specific steps for coarse adjustment via the water pump regulation unit in this embodiment are as follows: If the reflux regulating valve is fully open, but the gas temperature remains below 60°C, a fifth regulating command is issued through the water pump regulating unit to reduce the operating frequency of the circulating water pump (e.g., by 1-2 Hz each time). In this embodiment, reducing the frequency decreases the pump speed, reducing the total output water volume, thereby further reducing the amount of cooling water entering the gas cooler and causing the gas temperature to rise. In this embodiment, the water pump regulating unit continuously reduces the operating frequency of the water pump until the gas temperature returns to the 60°C-70°C range, or until the pump frequency drops to a preset minimum safe frequency (e.g., 30 Hz). If the temperature remains too low after the pump frequency drops to the minimum safe frequency, an alarm is issued through the water pump regulating unit, prompting the operator to check the process or equipment.

[0035] If the reflux regulating valve is fully closed, but the gas temperature is still above 70°C, a sixth regulating command is issued through the water pump regulating unit to increase the operating frequency of the circulating water pump (e.g., by 1-2 Hz each time). In this embodiment, increasing the frequency increases the pump speed, thereby increasing the total output water volume and thus increasing the amount of cooling water entering the gas cooler, enhancing the cooling effect. In this embodiment, the water pump regulating unit continuously increases the operating frequency of the water pump until the gas temperature returns to the 60°C-70°C range, or the frequency reaches the maximum allowable frequency (e.g., 50 Hz) and then stops.

[0036] In this embodiment, if the gas temperature returns to the target range of 60℃-70℃ during the adjustment process, further adjustment will be stopped, and the current water pump frequency and reflux valve opening will be maintained.

[0037] As can be seen from the above, this embodiment achieves fine-tuning of the gas temperature by continuously and slightly adjusting the cooling water flow through the reflux regulating valve, thus improving the accuracy and stability of temperature control. Furthermore, by prioritizing the use of the reflux valve, this embodiment reduces the frequency of speed adjustments to the circulating water pump inverter, extending the equipment's service life.

[0038] In one embodiment of this application, the cooling control module is further configured to: During the process of adjusting the opening of the reflux control valve, if the gas temperature is within the target temperature control range and continues to exceed the first preset time, the current opening of the reflux control valve will be used as the reference opening. Wait for the second preset time. If the gas temperature is not within the target temperature control range and the deviation between the gas temperature and the target temperature control range is less than the preset deviation threshold, then based on the reference opening and by adjusting the opening of the reflux regulating valve through the preset step size, continue to wait for the second preset time. If the gas temperature is within the target temperature control range, then keep the current flow rate of the cooling medium unchanged. If the gas temperature is not within the target temperature control range, the opening of the reflux regulating valve is adjusted by a preset step size until the gas temperature is within the target temperature control range, or if the gas temperature is still not within the target temperature control range after a preset number of times, the water pump regulating unit is triggered to adjust the frequency.

[0039] In this embodiment, the first preset time refers to the shortest duration required for the system to determine that the gas temperature has stabilized within the target temperature control range. This first preset time is used to characterize that the system has entered a steady state, avoiding misjudgments caused by instantaneous fluctuations. The second preset time refers to the time required for the system to wait for the gas temperature to respond and stabilize after completing one valve step adjustment. The preset deviation threshold refers to the allowable deviation of the gas temperature from the target temperature control range. When the temperature deviates from the range but the deviation value is small (i.e., the temperature slightly exceeds the lower limit of 63°C or the upper limit of 67°C), small step fine-tuning is preferred to avoid over-adjustment. The preset step size refers to the opening change of the reflux regulating valve in each adjustment. The larger the preset step size, the faster the adjustment speed but the lower the accuracy; the smaller the preset step size, the finer the adjustment but the slower the response. The preset number of times refers to the maximum allowable number of adjustment steps when using step size for continuous adjustment, for example, 5 times.

[0040] In this embodiment, when the temperature detection module 11 detects that the outlet temperature of the gas cooler is within the range of 60-70°C, the cooling control module 13 starts timing. If this temperature condition persists for more than a first preset time (e.g., 60 seconds), the system determines that it is currently in a stable operating condition. At this time, the cooling control module 13 records and stores the current opening value of the return flow regulating valve as a reference opening. This reference opening characterizes the valve position that can maintain temperature stability under the current operating conditions (e.g., gas flow rate, inlet temperature, cooling water temperature, etc.).

[0041] In this embodiment, after obtaining the reference valve opening, a second preset time (e.g., 30 seconds) is waited for the gas temperature to be continuously monitored during this time. During this period, no active adjustments are made; the current valve opening is simply kept unchanged to observe whether the system can continue to remain stable at the reference opening or whether the operating conditions begin to change.

[0042] In this embodiment, after the second preset time expires, the current gas temperature is detected again by the temperature detection unit 11, and the temperature comparison module 12 determines whether the gas temperature is still within the target temperature control range of 60-70℃. If it is within the target temperature control range, the system continues to wait for the next cycle to maintain the current stable operating condition. If it is not within the target temperature control range, the opening of the reflux regulating valve is adjusted based on the reference step size. Specifically, the direction of adjustment is first determined based on the gas temperature: if the gas temperature is below 60℃ (overcooled), the opening of the reflux regulating valve is increased (reducing the cooling water flow); if the temperature is above 70℃ (overheated), the opening of the reflux regulating valve is decreased (increasing the cooling water flow). After determining the direction of adjustment, starting from the reference opening, a single-step adjustment is performed according to a preset step size (e.g., 2% opening) (i.e., only one step is increased or decreased at a time), and the system waits for the second preset time (e.g., 30 seconds) again to re-detect the gas temperature.

[0043] This embodiment can also obtain the deviation value between the current gas temperature and the target temperature control range, and determine the degree of deviation of the current gas temperature based on the deviation value and the preset deviation threshold.

[0044] In this embodiment, if the deviation value is less than the preset deviation threshold, it is determined to be a small deviation. At this time, the opening of the reflux control valve is fine-tuned based on the reference opening. If the gas temperature has returned to the target range of 60-70℃, the adjustment is stopped, the current new valve opening is used as the new reference opening, and the next steady-state monitoring begins. If the gas temperature is still not within the target range after fine-tuning, the next adjustment is carried out according to the preset step size (increasing or decreasing the opening by 2%).

[0045] If the deviation is greater than or equal to the preset deviation threshold, it is considered a significant deviation. In this case, instead of fine-tuning from the baseline opening, the current opening is adjusted continuously and rapidly in one direction at preset step sizes (e.g., adjusting the opening by 2% every 30 seconds) until the temperature returns to the target range or the preset number of adjustments is reached. If, after multiple step adjustments, the cumulative number of adjustments has reached the preset number (e.g., 5 times), but the gas temperature still has not returned to the target range, it is determined that the reflux regulation capability is insufficient to overcome changes in operating conditions.

[0046] As can be seen from the above, this embodiment confirms the steady state after a first preset time before recording the reference opening, avoiding erroneous adjustments caused by instantaneous fluctuations and improving system stability. This embodiment also intelligently selects different adjustment strategies by distinguishing between small and large deviations—fine-tuning for small deviations and rapid response for large deviations.

[0047] In one embodiment of this application, a bypass valve is provided at the outlet of the circulating water pump. The cooling control module is also used to control the opening of the reflux regulating valve according to the gas temperature, and to control the circulating water pump to operate at a preset flow rate through the bypass valve.

[0048] In this embodiment, the preset flow rate refers to the minimum total output flow rate that the circulating water pump must maintain to ensure safe and stable operation.

[0049] In this embodiment, a bypass pipeline and a bypass valve are installed between the outlet of the circulating water pump and the cooling tower, and the actuator of the bypass valve is electrically connected to the electronic equipment.

[0050] In this embodiment, the cooling control module 13 collects the gas temperature at the outlet of the gas cooler in real time and compares it with the target range. If the gas temperature is below 60°C (overcooled), the reflux regulating valve is opened wider to reduce the effective water flow into the gas cooler, causing the temperature to rise. If the gas temperature is above 70°C (overheated), the reflux regulating valve is closed wider to increase the effective water flow, causing the temperature to drop. If the gas temperature is within the range of 60-70°C, the opening of the reflux valve remains unchanged.

[0051] During the adjustment of the return valve, the cooling control module 13 continuously monitors the total output flow of the circulating water pump. When the total flow is lower than the preset lower limit (e.g., 95 m³ / h), the opening of the bypass valve is increased to increase the bypass water volume, so that the total flow returns to the preset flow range until the safety requirements are met. When the total flow is higher than the preset upper limit (e.g., 105 m³ / h) and there is sufficient cooling capacity, the opening of the bypass valve is appropriately reduced to reduce ineffective circulation and save water pump power consumption.

[0052] In this embodiment, priority is given to ensuring the normal operation of the circulating water pump. If the bypass valve is fully open but the total flow rate is still lower than the preset lower limit, a "low flow alarm for water pump" will be issued to prompt the operator to check the pipeline or water pump. If the gas temperature cannot enter the target range for a long time and the opening of the return valve is already at the limit position, a "insufficient cooling regulation capacity" prompt will be issued.

[0053] As can be seen from the above, this embodiment ensures the safe operation of the circulating water pump by adding a bypass valve at the outlet of the circulating water pump and adopting a dual-loop coordinated control of "temperature control by the return valve and flow protection by the bypass valve".

[0054] In one embodiment of this application, the cooling control module further includes a frequency protection unit. The frequency protection unit is used to generate an alarm signal when the frequency of the circulating water pump drops to the preset minimum safe frequency. When the gas temperature is still below the lower limit of the target temperature control range, the bypass valve is triggered to open or the shutdown protection action is triggered.

[0055] In this embodiment, the frequency protection unit continuously collects the current output frequency value of the inverter of the circulating water pump. This frequency protection unit works in conjunction with the water pump regulation unit. When the gas temperature is lower than the target lower limit (60°C), the water pump regulation unit gradually reduces the operating frequency of the water pump to reduce the cooling water volume.

[0056] In this embodiment, when the water pump operating frequency drops to a preset minimum safe frequency (e.g., 30Hz), a protection operation is performed by the frequency protection unit. Specifically, the protection operation includes: Based on the current time and frequency value, an alarm signal is generated indicating that the circulating water pump frequency has reached the lower limit, reminding the operator to pay attention. At the same time, the frequency protection unit notifies the cooling control module 13 that the frequency adjustment can no longer be reduced (i.e., coarse adjustment methods have been exhausted).

[0057] In this embodiment, after the frequency protection unit issues an alarm, the temperature detection module 11 detects the gas temperature at the outlet of the gas cooler. If the gas temperature has risen back to the target range (60-70℃), the current frequency remains unchanged, and the alarm can be automatically reset or reset after operator confirmation. If the gas temperature is still below the lower limit of the target temperature control range (60℃), the system is determined to be in an abnormal state of "overcooling and exhaustion of regulation capacity," and the frequency protection unit executes any of the following schemes: Option 1 (with bypass valve): Trigger the bypass valve opening command to gradually increase the opening degree of the bypass valve, allowing some cooling water to return directly without passing through the gas cooler, further reducing the effective cooling water volume and thus causing the gas temperature to rise. If the temperature recovers after the bypass valve is fully open, maintain this state and retain the alarm; if the temperature is still too low after the bypass valve is fully open, execute Option 2.

[0058] Option 2 (when there is no bypass valve or the bypass valve is fully open and ineffective): Trigger shutdown protection action. In this embodiment, to avoid equipment damage or process abnormalities, the circulating water pump can be automatically stopped, and an emergency alarm "the pump has been automatically stopped due to the gas temperature being too low" can be sent, so that the operator can decide whether to resume operation based on process conditions (such as gas holder safety and pipeline corrosion risk).

[0059] In this embodiment, manual reset is required after the shutdown protection is triggered. If the gas temperature returns to normal due to troubleshooting or changes in operating conditions (e.g., because the converter stops blowing), the operator can manually restart the circulating water pump, and the system will re-enter automatic control mode.

[0060] As can be seen from the above, this embodiment adds a dual protection mechanism to the frequency conversion regulation by setting a frequency protection unit, which prevents the water pump from being damaged due to operation at too low a frequency and increases the service life of the equipment.

[0061] In one embodiment of this application, the system further includes a monitoring and evaluation module. The monitoring and evaluation module is used to monitor the temperature and instantaneous flow rate of the cooling medium and obtain monitoring data. Historical trend records are determined based on monitoring data and gas temperature. The effectiveness of the cooling control module is evaluated based on historical trend records.

[0062] In this embodiment, the temperature and instantaneous flow rate of the cooling medium are collected and monitored by a monitoring and evaluation module. The monitoring and evaluation module adds timestamps to the collected real-time data and stores it in a database to form a historical trend record. This embodiment provides a visualization interface, allowing operators to view data changes over any time period in the form of graphs or tables. For example, the visualization interface can simultaneously display multiple curves such as gas temperature, cooling water flow rate, and inlet / outlet water temperature, facilitating comparative analysis.

[0063] In this embodiment, the monitoring and evaluation module has built-in or external analysis tools to automatically or manually perform evaluations according to a preset cycle (e.g., daily, weekly, or monthly) and output an evaluation report. The evaluation report includes at least the following: temperature control accuracy assessment, power consumption assessment, water consumption assessment, and gas calorific value utilization rate assessment. Specifically, by statistically analyzing the target time during which the gas temperature remained within the target range (60-70℃) within the evaluation cycle, as well as the maximum deviation and duration from the range, the temperature control accuracy is determined based on the ratio of the target time to the duration. If the temperature control accuracy is below 95%, the control parameters are indicated as needing adjustment.

[0064] Based on the operating frequency of the circulating water pump and the instantaneous flow rate, determine the total power consumption (kWh) within the cycle. Compare this power consumption with historical data before optimization (or a set baseline power consumption) to determine the power saving rate and the amount of power saved. Then, evaluate the power consumption based on the power saving rate and the amount of power saved.

[0065] The total water consumption (m³) within the period is calculated by integrating the instantaneous flow rate. This total water consumption is then compared with that before optimization to determine the water saving amount and water saving benefits, thus completing the water consumption assessment.

[0066] Based on the relationship between gas temperature and saturated water content (which can be built into the water vapor saturation curve formula), the percentage decrease in gas water content after the gas temperature is increased is determined, and then the increase in gas calorific value is estimated, so as to evaluate the calorific value utilization rate based on the increase in gas calorific value.

[0067] In this embodiment, the monitoring and evaluation module summarizes the above evaluation results into a report and sends it to the operator. This allows the operator to identify the shortcomings of the control strategy (such as excessive temperature fluctuations during a certain period) based on the evaluation data, and then adjust the control parameters (such as preset step size, delay time, etc.) to achieve continuous optimization of the system.

[0068] As can be seen from the above, this embodiment sets up a monitoring and evaluation module, which continuously monitors, records and analyzes the system's operating data through specific indicators such as temperature qualification rate, power saving rate, water saving rate, and calorific value improvement rate, thereby achieving a quantifiable evaluation of the control effect.

[0069] In one embodiment of this application, the monitoring and evaluation module is further configured to: The change in gas moisture content is determined based on the correlation between gas temperature and saturated moisture content. The increase in the effective calorific value of coal gas is assessed based on changes in the moisture content of the coal gas.

[0070] In this embodiment, the monitoring and evaluation module pre-stores or programs the correspondence between gas temperature and saturated water content. This correspondence can be obtained based on steam thermodynamic property tables (e.g., Antoine formulas) or industry standard empirical data.

[0071] The monitoring and evaluation module obtains the gas temperature (or the average temperature over a specified time period) at the outlet of the gas cooler from the temperature detection module 11.

[0072] Based on the established correspondence, the gas moisture content (g / Nm³) corresponding to the current gas temperature can be obtained by querying.

[0073] In this embodiment, a reference temperature is set, which can be the typical outlet temperature before optimization, such as 52°C or 50°C. Based on the reference temperature and the above correspondence, the reference moisture content is determined.

[0074] The change in moisture content is determined by the difference between the baseline moisture content and the moisture content of the gas at the current gas temperature. If the change in moisture content is positive, it indicates that the moisture content has decreased and the gas quality has improved; if the change in moisture content is negative, it indicates that the moisture content has increased.

[0075] In this embodiment, after obtaining the change in moisture content, the change in moisture content is multiplied by the latent heat of vaporization of water (e.g., 2260 kJ / kg) to obtain the increase in calorific value; then, combined with the instantaneous flow rate of coal gas and the annual operating time, the annual energy saving is determined, which is used to quantify the effect of temperature control optimization on the improvement of coal gas quality.

[0076] As can be seen from the above, this embodiment uses the correspondence between the change in gas temperature and the change in moisture content to quantitatively assess the change in moisture content and the increase in effective calorific value.

[0077] In one embodiment of this application, the monitoring and evaluation module is further configured to: The control precision of the gas temperature is determined based on the gas temperature. The results of the power consumption adjustment of the control system are evaluated by analyzing the deviation between the control accuracy and the target temperature control range, as well as the relationship between the power consumption change of the circulating water pump and the flow rate of the cooling medium.

[0078] As can be seen from the above, in this embodiment, the monitoring and evaluation module counts the total time that the gas temperature at the outlet of the gas cooler is within the target range of 60-70℃ within a set evaluation period (e.g., daily, weekly, or monthly), and divides it by the total running time within that period to obtain the temperature qualification rate (unit: %).

[0079] The monitoring and evaluation module records the total power consumption (kWh) of the circulating water pump and the average cooling water flow rate (m³ / h) during the evaluation period. The actual power saving rate is obtained by comparing the optimized actual power consumption with the power consumption before optimization (or the theoretical baseline). The calculation method can be: Actual power saving rate = (Power consumption before optimization - Power consumption after optimization) / Power consumption before optimization × 100%.

[0080] This embodiment determines the theoretical energy saving rate based on the flow rate change and the "cubic (or square) relationship between flow rate and power consumption" (the relationship is usually cubic for variable frequency water pumps, but close to linear for regulating valves). The actual energy saving rate is compared with the theoretical energy saving rate to verify whether the regulation effect meets the standard.

[0081] Based on the temperature control accuracy and power consumption analysis, this embodiment obtains the following evaluation conclusion: if the temperature qualification rate is higher than 95% and the power consumption reduction meets the theoretical expectation, the control system is judged to have excellent adjustment effect; if the temperature qualification rate is higher than 95% but the power consumption reduction is low, it indicates that there may be excessive cooling or unreasonable water pump operation (e.g., large valve throttling loss); if the temperature qualification rate is lower than 95%, regardless of the power consumption, the control parameters are judged to need to be readjusted.

[0082] As can be seen from the above, this embodiment achieves an objective evaluation of the control system's adjustment effect by quantifying the temperature control accuracy and comparing the theoretical relationship between power consumption and flow rate, thus avoiding the long-term deviation of gas temperature from the optimal range due to parameter drift.

[0083] For example, the above control system is applied to the converter gas recovery system of a steel plant. The converter gas recovery system of the steel plant is configured as follows: converter gas recovery rate of 47,000 Nm³ / h, gas inlet temperature of approximately 163°C at the gas cooler, gas outlet temperature of 52°C at the gas cooler before optimization, circulating water volume of 285 m³ / h, and annual operating time of 8,400 hours.

[0084] This example first sets the target temperature control range of the temperature comparison module 12 to 60-70℃ (preferably 65℃±2℃). The temperature detection module 11 acquires the outlet gas temperature of the gas cooler in real time, and the temperature comparison module 12 compares the measured temperature with the 60-70℃ range. Based on the comparison result, the cooling control module 13 first fine-tunes the opening of the reflux regulating valve through the reflux regulating unit. When the reflux regulation capacity is insufficient, the water pump regulating unit adjusts the frequency of the circulating water pump to stabilize the outlet gas temperature within the target range.

[0085] After operation and debugging, the control system achieved the following quantitative results: the outlet gas temperature of the gas cooler was stably controlled within the range of 63-67℃, with an average temperature of 65.2℃ and a control accuracy of ±2℃; the cooling load was reduced by 11.7%, and the actual circulating water volume decreased from 285 m³ / h to 252 m³ / h, a reduction of 11.6%, resulting in annual water savings of 277,000 tons / year; the pump frequency decreased from 48Hz to 42Hz, reducing power consumption by approximately 27%; and the gas temperature increased from 52℃ to 65℃, corresponding to a reduction in saturated water content of approximately 30%. This embodiment verifies the significant effects of the control system of this application in improving temperature control accuracy, reducing water and electricity consumption, and increasing the utilization rate of gas calorific value.

[0086] In one embodiment of this application, the cooling control module further includes a feedforward adjustment unit. The feedforward control unit is used to obtain the rate of change of gas temperature. When the rate of change is higher than the preset rate of change threshold, the control signal is output to the reflux control unit or the water pump control unit to pre-adjust the flow rate of the cooling medium.

[0087] In this embodiment, the preset rate of change threshold refers to a pre-set absolute value of the rate of change. When the actual rate of change exceeds this value, it indicates that the feedforward adjustment unit is triggered. In this embodiment, the preset rate of change threshold is set to 1°C / minute.

[0088] In this embodiment, the feedforward adjustment unit continuously receives data from the temperature detection module and calculates the current temperature change rate every certain time interval (e.g., 10 seconds) (the differential average of the most recent temperature values ​​can be used).

[0089] The calculated absolute value of the rate of change is compared with a preset threshold: if the absolute value of the rate of change is less than or equal to the preset threshold, the feedforward adjustment unit does not make any adjustment; if the absolute value of the rate of change is greater than the preset threshold, the feedforward adjustment unit outputs an adjustment signal to the return flow adjustment unit or the water pump adjustment unit.

[0090] In this embodiment, the feedforward control unit issues corresponding adjustment commands based on the direction of the rate of change: if the rate of change is positive (temperature rises rapidly), the cooling water flow is increased in advance (e.g., the reflux control valve is closed in advance, or the water pump frequency is increased in advance) to prevent the temperature from overshooting; if the rate of change is negative (temperature drops rapidly), the cooling water flow is reduced in advance (e.g., the reflux control valve is opened in advance, or the water pump frequency is reduced in advance) to prevent the temperature from dropping too low.

[0091] In this embodiment, feedforward adjustment is a temporary, proactive action and does not replace feedback control. After issuing the feedforward command, the system continues to adjust based on the deviation between the actual temperature and the target range. The combination of these two approaches achieves a balance between rapid response and precise stability.

[0092] As can be seen from the above, by setting up a feedforward adjustment unit, this embodiment can adjust the cooling water flow rate in advance according to the rate of change of gas temperature before the deviation increases when the temperature changes rapidly (such as when the converter blowing cycle changes or the gas flow rate changes suddenly). This improves the response speed of the control system and reduces the possibility of temperature over-adjustment.

[0093] For example, if the converter gas cooling control system is configured as follows: converter gas recovery rate is 47,000 Nm³ / h, gas temperature at the inlet of the coal cooler is about 163℃, gas temperature at the outlet of the coal cooler is 52℃, circulating water volume is 285 m³ / h, and annual operating time is 8400 hours.

[0094] In this embodiment, the target temperature for controlling the gas temperature at the outlet of the gas cooler is set to 60-70℃, with a target value of 65℃±2℃.

[0095] This embodiment adds a control module to the existing converter gas cooling control system. For example, a temperature detection unit 6 is added to the gas outlet of the gas cooler to collect the outlet gas temperature in real time. The collected gas temperature is input to the controller 10. The signals output by the controller 10 control the opening degree of the reflux regulating valve 8 and the frequency of the frequency converter control unit 9, respectively. See [link to relevant documentation]. Figure 2This is a schematic diagram of the cooling control module of a gas cooler. The cooling control module includes a coal cooler 1, a converter gas pipeline 2, a purification and recovery unit 3, a cooling tower 4, a circulating water pump 5, a temperature detection unit 6, a return pipe 7, a return regulating valve 8, a frequency conversion control unit 9, and a controller 10.

[0096] In this embodiment, if the gas temperature is detected to be less than 60°C, the reflux regulating valve is increased to reduce the amount of circulating water entering the coal cooler; if the reflux valve is fully open and still cannot meet the requirements, the frequency of the circulating water pump 5 is reduced. If the detected gas temperature is greater than 70℃, the reflux regulating valve is reduced to increase the amount of circulating water entering the coal cooler; if the reflux valve is fully closed and the requirement cannot be met, the frequency of the circulating water pump is increased. If the gas temperature is detected to be within the range of 60-70℃, the current operating parameters shall remain unchanged.

[0097] In this embodiment, the cooling control module can stably control the outlet gas temperature of the coal cooler within the range of 63-67℃, with an average temperature of 65.2℃ and a control accuracy of ±2℃.

[0098] For example, if a large load fluctuation is detected in the system, a segmented control strategy is adopted: If the gas temperature is within the target temperature range, PID continuous regulation is used; if the gas temperature exceeds the target temperature range by a large margin (for example, more than 5°C below the lower limit of the range, or more than 5°C above the upper limit of the range), a fast regulation mode is used, prioritizing the rapid adjustment of the reflux valve opening.

[0099] This embodiment adds a temperature change rate feedforward control. If the temperature change rate exceeds the set threshold, it will be adjusted in advance to improve the response speed of the system.

[0100] In this embodiment, if the system does not have the capability for frequency conversion regulation, a separate control mode for the regulating valve can be used: An electric regulating valve is added to the outlet of the circulating water pump. The controller controls the opening of the regulating valve according to the temperature signal at the outlet to regulate the circulating water volume. A return pipe and a bypass valve are installed between the pump outlet and the cooling tower to ensure that the water pump can still operate stably at the minimum flow rate.

[0101] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A converter gas cooling control system, characterized in that, include: The temperature detection module is used to obtain the gas temperature at the outlet of the gas cooler; A temperature comparison module is used to compare the gas temperature with the target temperature control range; The cooling control module is used to control the flow rate of the cooling medium in the gas cooler based on the comparison result; wherein, if the gas temperature is lower than the lower limit of the target temperature control range, the flow rate of the cooling medium is reduced; if the gas temperature is higher than the upper limit of the target temperature control range, the flow rate of the cooling medium is increased; if the gas temperature is within the target temperature control range, the current flow rate of the cooling medium is kept unchanged.

2. The converter gas cooling control system as described in claim 1, characterized in that, The cooling medium inlet of the gas cooler is connected to the outlet of the circulating water pump, the cooling medium outlet of the gas cooler is connected to one end of the cooling medium return pipe, and the other end of the cooling medium return pipe is connected to the inlet of the circulating water pump. The cooling control module includes a return regulating unit and a water pump regulating unit. The reflux regulating unit is used to adjust the opening of the reflux regulating valve installed on the cooling medium reflux pipe to control the flow rate of the cooling medium. When the gas temperature is lower than the lower limit of the target temperature control range, the opening of the reflux regulating valve is increased until the reflux regulating valve reaches the fully open state; when the gas temperature is higher than the upper limit of the target temperature control range, the opening of the reflux regulating valve is decreased until the reflux regulating valve reaches the fully closed state. The water pump regulating unit is used to adjust the operating frequency of the circulating water pump to control the flow rate of the cooling medium. If the reflux regulating valve is in a fully open or fully closed state, and the gas temperature is still not within the target temperature control range, the frequency of the circulating water pump is reduced or increased by the water pump regulating unit.

3. The converter gas cooling control system as described in claim 2, characterized in that, The cooling control module is also used for: During the process of adjusting the opening of the reflux regulating valve, if the gas temperature is within the target temperature control range and continues to exceed the first preset time, the current opening of the reflux regulating valve is taken as the reference opening. If the gas temperature is not within the target temperature control range after waiting for a second preset time, and the deviation between the gas temperature and the target temperature control range is less than a preset deviation threshold, then based on the reference opening, the opening of the reflux regulating valve is adjusted by a preset step size. After waiting for another second preset time, if the gas temperature is within the target temperature control range, then the current flow rate of the cooling medium remains unchanged. If the gas temperature is not within the target temperature control range, the opening of the reflux regulating valve is adjusted by the preset step size until the gas temperature is within the target temperature control range, or if the gas temperature is still not within the target temperature control range after a preset number of times, the water pump regulating unit is triggered to adjust the frequency.

4. The converter gas cooling control system as described in claim 3, characterized in that, A bypass valve is installed at the outlet of the circulating water pump. The cooling control module is also used to control the opening of the reflux regulating valve according to the gas temperature, and to control the circulating water pump to operate at a preset flow rate through the bypass valve.

5. The converter gas cooling control system as described in claim 4, characterized in that, The cooling control module also includes a frequency protection unit. The frequency protection unit is used for: An alarm signal is generated when the frequency of the circulating water pump drops to a preset minimum safe frequency. When the gas temperature is still below the lower limit of the target temperature control range, the bypass valve is triggered to open or the shutdown protection action is triggered.

6. The converter gas cooling control system as described in claim 1, characterized in that, The system also includes a monitoring and evaluation module. The monitoring and evaluation module is used for: The temperature and instantaneous flow rate of the cooling medium are monitored to obtain monitoring data; Historical trend records are determined based on the monitoring data and the gas temperature. The control effect of the cooling control module is evaluated based on the historical trend records.

7. The converter gas cooling control system as described in claim 6, characterized in that, The monitoring and evaluation module is also used for: Based on the relationship between the gas temperature and the saturated water content, the change in the gas water content is determined; The increase in the effective calorific value of the gas is assessed based on the change in the gas moisture content.

8. The converter gas cooling control system as described in claim 6, characterized in that, The monitoring and evaluation module is also used for: The control precision of the gas temperature is determined based on the gas temperature. The power consumption adjustment results of the control system are evaluated based on the deviation between the control accuracy and the target temperature control range, and by analyzing the relationship between the power consumption change of the circulating water pump and the cooling medium flow rate.

9. The converter gas cooling control system as described in claim 2, characterized in that, The cooling control module also includes a feedforward adjustment unit. The feedforward adjustment unit is used to obtain the rate of change of the gas temperature. When the rate of change is higher than a preset rate of change threshold, the adjustment signal is output to the reflux adjustment unit or the water pump adjustment unit to pre-adjust the flow rate of the cooling medium.

10. The converter gas cooling control system as described in claim 1, characterized in that, The target temperature control range is 60℃-70℃.

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