Liquid level control method, system and equipment of steam-water separator and medium

Abstract

The invention provides a liquid level control method, system and equipment of a steam-water separator and a medium, and belongs to the technical field of steam treatment.The method comprises the steps that operation parameters of the steam-water separator are collected, and the operation parameters comprise the current liquid level value, the inlet steam flow, the outlet steam dryness value and the internal pressure value of the interior of the steam-water separator; on the basis of the target steam dryness value and the outlet steam dryness value, the optimal liquid level set value of the next sampling period is obtained through calculation; the optimal liquid level set value is used as a tracking target, and according to the current liquid level value, the inlet steam flow, the outlet steam dryness value and the internal pressure value, the optimal blow-down valve opening degree of the electric blow-down valve is obtained through solving; and the electric blow-down valve is driven to act according to the optimal blow-down valve opening degree, the blow-down amount of the steam-water separator is adjusted, and the current liquid level value is kept at the optimal liquid level set value. According to the method, the energy consumption is obviously reduced while the optimal steam purity is ensured.

Description

Technical Field

[0001] This invention relates to the field of steam treatment technology, specifically to a liquid level control method, system, equipment, and medium for a steam-water separator. Background Technology

[0002] In energy and process industries such as power generation, chemical engineering, and pharmaceuticals, boiler-generated steam is a crucial power and process medium. However, boiler outlet steam often carries boiler water, which contains a large amount of soluble salts and solid particulate impurities. If this contaminated steam enters downstream precision equipment such as turbines and heat exchangers without adequate purification, it will lead to severe scaling, corrosion, and erosion problems. This will not only significantly reduce equipment efficiency and lifespan but may also cause unplanned downtime, resulting in significant economic losses.

[0003] To address the problem of impurities entrained in steam, steam-water separators have become the core purification device in modern steam systems. Currently, widely used industrial steam-water separation technologies are primarily based on a combination of various mechanical separation principles. These include: gravity settling chambers that utilize gravity for initial separation; baffles that use flow channel deflection to generate inertia in the steam flow for droplet separation; cyclone separators that rely on centrifugal force generated by swirling flow to throw droplets against the wall; and high-efficiency wire mesh collectors that use a fine mesh layer to intercept and agglomerate micron-sized droplets. The integrated application of these technologies aims to maximize the removal of liquid moisture and suspended solid particles from steam.

[0004] Although the aforementioned mechanical separation technologies are relatively mature, the overall performance of steam-water separators is largely constrained by the accuracy and strategy of their internal liquid level control. The liquid level directly determines the allocation of steam separation space and water storage space, profoundly affecting the flow field structure and separation kinetics. Currently, the industry commonly uses two-position control based on liquid level switches or conventional PID control based on fixed setpoints to maintain liquid level stability. However, these control methods are inherently static and passive; their control objective is merely to maintain the liquid level setpoint, rather than directly optimizing the steam purification effect. Therefore, the system cannot adaptively adjust to the optimal separation state according to real-time changes in steam load, impurity concentration, and other operating conditions, leading to decreased separation efficiency under varying operating conditions, or wasting a large amount of high-quality working fluid and thermal energy to maintain ineffective liquid level stability. This disconnect between the control objective and the final process effect has become a key bottleneck restricting further improvement in steam quality. Summary of the Invention

[0005] In view of this, it is necessary to provide a liquid level control method, system, equipment and medium for a steam-water separator to solve the technical problem of the disconnect between the control target and the final process effect in the prior art.

[0006] To solve the above-mentioned technical problems, in a first aspect, the present invention provides a liquid level control method for a steam-water separator, comprising: The operating parameters of the steam-water separator are collected, including the current liquid level, inlet steam flow rate, outlet steam dryness, and internal pressure. Based on the target steam dryness value and the outlet steam dryness value, the optimal liquid level setting value for the next sampling cycle is calculated. Using the optimal liquid level setting as the tracking target, the optimal drain valve opening of the electric drain valve is obtained by calculating the current liquid level value, the inlet steam flow rate, the outlet steam dryness value, and the internal pressure value. The electric drain valve is driven to operate according to the optimal drain valve opening, thereby adjusting the drain volume of the steam-water separator and maintaining the current liquid level at the optimal liquid level setting value.

[0007] In one possible implementation, calculating the optimal liquid level setpoint for the next sampling period based on the target steam dryness value and the outlet steam dryness value includes: The average steam dryness value is calculated based on the outlet steam dryness value. Based on the average steam dryness value and the target steam dryness value, the optimal liquid level setting value for the next sampling period is determined; the optimal liquid level setting value is located between the lower limit of the liquid level and the upper limit of the liquid level.

[0008] In one possible implementation, determining the optimal liquid level setpoint for the next sampling period based on the average steam dryness value and the target steam dryness value includes: A first critical value and a second critical value are calculated based on the target steam dryness value; the first critical value is equal to the difference between the target steam dryness value and the lower threshold value, and the second critical value is equal to the sum of the target steam dryness value and the upper threshold value, wherein the upper threshold value is greater than the lower threshold value; Compare the average steam dryness value with the first critical value and the second critical value; If the average steam dryness value is less than the first critical value, it is determined that the steam dryness does not meet the standard. The liquid level reduction amount is calculated based on the target steam dryness value, the lower limit threshold, the average steam dryness value, and the down-adjustment optimization gain. The optimal liquid level setting value for the next sampling period is determined to be equal to the maximum value of the liquid level lower limit value and the first sum value. The first sum value is equal to the sum of the current optimal liquid level setting value and the liquid level reduction amount. If the average steam dryness value is greater than the second critical value, it is determined that there is a surplus in steam dryness. The liquid level adjustment amount is calculated based on the target steam dryness value, the upper limit threshold, the average steam dryness value, and the upward optimization gain. The optimal liquid level setting value for the next sampling period is determined to be equal to the minimum value of the upper limit value and the second sum value. The second sum value is equal to the sum of the current optimal liquid level setting value and the liquid level adjustment amount.

[0009] In one possible implementation, the step of tracking the optimal liquid level setpoint and determining the optimal drain valve opening of the electric drain valve based on the current liquid level, the inlet steam flow rate, the outlet steam dryness value, and the internal pressure value includes: Based on the current liquid level, the inlet steam flow rate, the outlet steam dryness fraction, and the internal pressure, the predicted liquid level for the next moment is calculated: ; in, Let k be the current liquid level value at the current time. To predict the liquid level at time k+1, The sampling period is This refers to the average cross-sectional area of ​​the gas-water separator within its normal operating liquid level range. The density of the water phase within the steam-water separator. Let K be the inlet steam flow rate at time k. Let k be the outlet steam dryness value. The density of saturated water in the steam-water separator at the current operating pressure is given. The flow coefficient of the electric drain valve. Let k be the optimal opening degree of the electric drain valve to be determined at time k. Let k be the internal pressure value of the steam-water separator at time k; Using the optimal liquid level setpoint as the tracking target, the optimal drain valve opening is calculated based on the predicted liquid level value, and the liquid level value at the next moment and the optimal drain valve opening satisfy preset constraints: ; in, and For prediction in the time domain and control in the time domain, The penalty weighting coefficient for changes in the control quantity Set the liquid level value. This represents the magnitude of the change in valve opening between two adjacent future time points. It is a time index variable; the preset constraints include: ; ; in, To reduce the optimization gain, To optimize the gain, This is the lower limit of the liquid level. This is the upper limit of the liquid level.

[0010] In one possible implementation, the downward optimization gain is set based on the effective volume and processing flow rate of the gas-water separator, and the upward optimization gain is set to 1 / 5 to 1 / 10 of the downward optimization gain.

[0011] One possible implementation also includes: When the internal pressure value exceeds the preset safety pressure threshold, the pressure relief valve is fully opened to perform emergency pressure relief.

[0012] One possible implementation also includes: Obtain the change data of the outlet steam dryness value after liquid level control based on the optimal liquid level setting value; The actual response characteristic quantities are calculated based on the changed data; the actual response characteristic quantities include the actual overshoot and the actual settling time. The actual response characteristics are compared with the expected response characteristics; the expected response characteristics include the expected overshoot and the expected settling time. If the actual overshoot is greater than the expected overshoot, the down-adjustment optimization gain is reduced by a first preset ratio. If the actual adjustment time is greater than the expected adjustment time, and the actual overshoot is less than or equal to the expected overshoot, the down-adjustment optimization gain is increased by a second preset ratio. Based on the updated downward optimization gain, the upward optimization gain is synchronously updated according to a preset fixed ratio.

[0013] Secondly, the present invention also provides a liquid level control system for a steam-water separator, comprising: Steam-water separator; The data acquisition module includes a level gauge for monitoring the current liquid level inside the steam-water separator, a steam flow meter for monitoring the inlet steam flow, a steam dryness meter for monitoring the outlet steam dryness, and a pressure gauge for monitoring the internal pressure. The execution module includes an electric drain valve located at the bottom of the steam-water separator; The processor is configured to receive operating parameters from the data acquisition module, including the current liquid level, inlet steam flow rate, outlet steam dryness, and internal pressure of the steam-water separator; calculate the optimal liquid level setpoint for the next sampling period based on the target steam dryness and the outlet steam dryness; track the target using the optimal liquid level setpoint, and determine the optimal drain valve opening of the electric drain valve based on the current liquid level, the inlet steam flow rate, the outlet steam dryness, and the internal pressure. The controller is used to send the optimal drain valve opening value to the execution module, so as to drive the electric drain valve to operate according to the optimal drain valve opening value, adjust the drain volume of the gas-water separator, and maintain the current liquid level value at the optimal liquid level setting value.

[0014] Thirdly, the present invention also provides an electronic device, including a memory and a processor, wherein, The memory is used to store programs; The processor, coupled to the memory, is used to execute the program stored in the memory to implement the steps in the liquid level control method of the steam-water separator described in any of the above implementations.

[0015] Fourthly, the present invention also provides a computer-readable storage medium for storing a computer-readable program or instructions, which, when executed by a processor, can implement the steps in the liquid level control method of the steam-water separator described in any of the above implementations.

[0016] The beneficial effects of this invention are as follows: The liquid level control method for the steam-water separator provided by this invention first uses the final process indicator of outlet steam dryness as the core feedback signal. Through a supervised optimization algorithm, it dynamically optimizes the liquid level setpoint, ensuring that regardless of changes in operating conditions, the system can always automatically maintain the liquid level at the point of highest separation efficiency under the current conditions. This continuously outputs high-purity steam, fundamentally protecting downstream equipment from scaling and corrosion, and achieving continuous optimization of impurity removal efficiency and steam quality. Furthermore, based on the current liquid level, inlet steam flow rate, outlet steam dryness, and internal pressure, the optimal opening degree of the electric drain valve is calculated. This allows for pre-emptive valve adjustment to compensate for measurable but unaffected disturbances (such as flow rate changes) before they affect the liquid level. This results in a faster and more stable system response to load changes, completely overcoming drastic fluctuations in liquid level and improving the system's anti-interference capability and control stability. Furthermore, the system features gain self-tuning and adaptive fine-tuning capabilities, automatically adjusting control parameters based on the slow performance degradation of equipment during long-term operation (such as volume changes caused by scaling), maintaining excellent performance and reducing manual maintenance. The system drives the electric drain valve to operate according to the optimal drain valve opening, adjusting the drain volume of the steam-water separator 10 to maintain the current liquid level at the optimal setpoint. This not only improves steam quality and equipment safety but also achieves significant energy savings through intelligent optimization and predictive control, making it suitable for industrial scenarios such as power generation, chemical processing, and pharmaceuticals where high steam purity and system energy efficiency are required. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic flowchart of an embodiment of the liquid level control method for a steam-water separator provided by the present invention; Figure 2 A schematic diagram of an embodiment of the liquid level control system of the steam-water separator provided by the present invention; Figure 3 For the present invention Figure 1 A schematic diagram of an embodiment of S102; Figure 4 For the present invention Figure 3 A schematic diagram of an embodiment of S302; Figure 5 A schematic flowchart of another embodiment of the liquid level control method for the steam-water separator provided by the present invention; Figure 6A schematic diagram of an embodiment of the electronic device provided by the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] In the description of the embodiments of the present invention, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0021] The terms "first," "second," etc., used in the embodiments of this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a technical feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] This invention provides a liquid level control method, system, equipment, and medium for a steam-water separator, which will be described below.

[0024] Figure 1 This is a schematic flowchart of an embodiment of the liquid level control method for a steam-water separator provided by the present invention. Figure 2 This is a schematic diagram of an embodiment of the liquid level control system for the steam-water separator provided by the present invention. Figure 1 As shown, the liquid level control method for the steam-water separator includes: S101. Collect the operating parameters of the steam-water separator, including the current liquid level, inlet steam flow rate, outlet steam dryness, and internal pressure inside the steam-water separator.

[0025] It should be noted that: such as Figure 2As shown, boiler 1 serves as the steam source and is the starting point of the entire system. Safety valve 2 is installed at the outlet of boiler 1 or on the main steam pipeline near it for overpressure protection. A pre-operated electric valve 3 is located downstream of safety valve 2 on the main steam pipeline, serving as a manual or programmable shut-off valve before the steam enters the purification system. Filter 4 is connected after pre-operated electric valve 3 for preliminary mechanical filtration of the steam. Steam flow meter 5 is installed on the main steam pipeline after filter 4 to measure the steam flow rate entering the separator. Pressure gauge 6 is installed on the body of steam-water separator 10 to directly monitor the operating pressure inside the separator. Steam flow meter 5 is connected upstream of steam-water separator 10 via a pipeline, and outlet electric valve 8 is connected downstream, with a drain port at its bottom. Steam dryness meter 9 is installed on the clean steam outlet pipeline of steam-water separator 10 to monitor the quality of the purified steam online. Outlet electric valve 8 is installed downstream of steam dryness meter 9 on the clean steam outlet pipeline to control the delivery of purified steam. Level gauge 11 is directly installed on the side wall of the steam-water separator 10 cylinder to monitor the liquid level inside the separator in real time. An electric drain valve 12 is installed on the drain pipe at the bottom of the steam-water separator 10 for liquid level control. A steam trap 13 is connected to the drain pipe after the electric drain valve 12 for automatic steam blocking and drainage. A pressure relief valve 7 is installed directly on the top of the steam-water separator 10 or in the upper gas phase space, serving as a dedicated safety valve 2 for the separator body. Steam enters the steam-water separator 10 along the path of boiler 1 → [safety valve 2] → pre-powered electric valve 3 → filter 4 → steam flow meter 5. After purification within the separator, the dry steam is output via the top steam dryness meter 9 and the outlet electric valve 8. The separated water settles to the bottom, is monitored by the liquid level gauge 11, and is discharged through the pipeline consisting of the electric drain valve 12 and the steam trap 13. During system operation, the following operating parameters are collected in real time by sensors deployed at key nodes: current liquid level, inlet steam flow rate, outlet steam dryness, and internal pressure.

[0026] S102. Based on the target steam dryness value and the outlet steam dryness value, calculate the optimal liquid level setting value for the next sampling cycle.

[0027] It should be noted that the system uses the target steam dryness as a benchmark, forming a closed-loop feedback with the real-time monitored outlet steam dryness. Through intelligent algorithms, the deviation between the two is analyzed, and the optimal liquid level setpoint that can drive the system towards optimal separation efficiency in the next sampling period is dynamically calculated, thereby achieving online adaptive optimization of the liquid level parameters.

[0028] S103. Using the optimal liquid level setting as the tracking target, the optimal drain valve opening of the electric drain valve 12 is obtained based on the current liquid level, the inlet steam flow rate, the outlet steam dryness value, and the internal pressure value.

[0029] It should be noted that the controller includes a host computer and a slave computer. The slave computer dynamically tracks the target based on the received optimal liquid level setpoint. In each control cycle, based on an embedded simplified process model, it synchronously collects real-time data on multiple variables, including the current liquid level, inlet steam flow rate, outlet steam dryness, and separator internal pressure. Based on the Model Predictive Control (MPC) algorithm, rolling optimization is performed using the current liquid level, inlet steam flow rate, outlet steam dryness, and separator internal pressure as a basis. The optimal drain valve opening is calculated to ensure the liquid level smoothly and accurately approaches the setpoint.

[0030] S104. Drive the electric drain valve 12 to operate according to the optimal drain valve opening, adjust the drain volume of the steam-water separator 10, and maintain the current liquid level at the optimal liquid level setting value.

[0031] It should be noted that the controller analyzes and converts the optimal drain valve opening into the real-time opening of the electric drain valve 12. By adjusting the valve opening of the electric drain valve 12, the continuous drain flow of the separator is precisely controlled, thus forming a closed-loop regulation process: that is, based on the liquid level deviation, the drain volume (discharged sewage flow) of the steam-water separator 10 is dynamically adjusted, thereby changing the water volume in the separator, so that the actual liquid level (current liquid level value) at the current moment dynamically and smoothly approaches the optimal liquid level set value, and finally stabilizes within the allowable fluctuation range. In other words, the optimal drain valve opening directly drives the electric drain valve 12 to act, changing its opening to regulate the drain volume. The change in the drain volume has a reverse effect on the water level in the separator. Through the negative feedback regulation mechanism, the current liquid level value is ultimately driven to converge to the preset optimal liquid level set value, and is stably maintained near the optimal liquid level set value.

[0032] In summary, the liquid level control method for the steam-water separator provided in this embodiment of the invention first uses the final process indicator of outlet steam dryness as the core feedback signal. Through a supervised optimization algorithm, it dynamically optimizes the liquid level setpoint, ensuring that regardless of changes in operating conditions, the system can always automatically maintain the liquid level at the point of highest separation efficiency under the current conditions. This continuously outputs high-purity steam, fundamentally protecting downstream equipment from scaling and corrosion, and achieving continuous optimization of impurity removal efficiency and steam quality. Furthermore, based on the current liquid level, inlet steam flow rate, outlet steam dryness, and internal pressure, the optimal opening degree of the electric drain valve 12 is calculated. This allows for pre-emptive valve adjustment and compensation through feedforward before interference (such as flow rate changes) becomes measurable but does not affect the liquid level. This makes the system respond to load changes faster and more smoothly, completely overcoming drastic fluctuations in liquid level and improving the system's anti-interference capability and control stability. Furthermore, the system features gain self-tuning and adaptive fine-tuning capabilities, automatically adjusting control parameters based on the slow performance degradation of equipment during long-term operation (such as volume changes due to scaling), maintaining excellent performance and reducing manual maintenance. The electric drain valve 12 is driven to operate according to the optimal drain valve opening, adjusting the drain volume of the steam-water separator 10 to maintain the current liquid level at the optimal setpoint. This not only improves steam quality and equipment safety but also achieves significant energy savings through intelligent optimization and predictive control, making it suitable for industrial scenarios such as power generation, chemical processing, and pharmaceuticals where high steam purity and system energy efficiency are required.

[0033] In traditional methods, the liquid level setpoint is disconnected from real-time steam quality (dryness), making dynamic optimization based on actual impurity removal performance impossible. This leads to a mismatch between the control objective (stable liquid level) and the process objective (optimal impurity removal). To transform the real-time, fluctuating steam dryness measurement into a stable, reliable, and safe optimal liquid level control objective, some embodiments of this invention, such as... Figure 3 As shown, step S102 includes: S301. Calculate the average steam dryness value based on the outlet steam dryness value.

[0034] It should be noted that filtering algorithms can be used to filter the raw outlet steam dryness signal X(k) acquired in real time to obtain an average steam dryness value Xavg that truly reflects the process status and removes random interference. The filtering algorithm can use a first-order low-pass digital filter (exponentially weighted moving average), or it can perform a moving average filter on the instantaneous value, for example, using a first-in-first-out queue of length N (e.g., N=60, corresponding to 1 minute of data) and calculating its arithmetic mean. In short, the average steam dryness value for the current sampling period is calculated based on the outlet steam dryness value at each moment within the current sampling period.

[0035] S302. Determine the optimal liquid level setting value for the next sampling period based on the average steam dryness value and the target steam dryness value; the optimal liquid level setting value is located between the lower limit of the liquid level and the upper limit of the liquid level.

[0036] It should be noted that the optimal liquid level setpoint for the next cycle is dynamically calculated and constrained. The system compares the average steam dryness value with the target steam dryness value, and dynamically calculates the expected optimal liquid level setpoint for the next sampling cycle based on a preset optimization algorithm and gain coefficient. Subsequently, a lower limit liquid level is applied to this optimal liquid level setpoint. L low With upper limit of liquid level L high The constraint, that is, the optimal liquid level setpoint belongs to [ L low , L high Within this range, the optimal liquid level setpoint is determined to both align with process optimization and ensure safe equipment operation. The lower and upper liquid level limits are not fixed but are calibrated based on computational fluid dynamics (CFD) simulations and actual operating condition tests. First, CFD simulations of the internal flow field and droplet trajectory at different liquid levels are used to initially determine a liquid level window with stable flow and low risk of secondary entrainment. Then, near this liquid level window, the steam load and impurity concentration are varied on an experimental bench, and the outlet dryness and impurity content are measured. Finally, the liquid level range that simultaneously meets the dryness requirements and impurity removal rate is calibrated as the safe operating range. L low , L high ].

[0037] In this embodiment, the average steam dryness value is calculated through filtering, effectively removing high-frequency random noise and transient disturbances from the steam dryness signal. This avoids the controller's overreaction to invalid fluctuations, fundamentally preventing frequent oscillations of the setpoint and its subsequent control actions, and ensuring a smooth optimization process. The search range for the optimal liquid level setpoint is strictly constrained within the safe range calibrated by CFD and experiments. L low , L high Within this range, the system can dynamically find and lock the optimal operating point under the current conditions based on the dryness feedback without compromising the stability of the flow field and the separation space. This enables the system to switch from fixed liquid level control to adaptive optimal liquid level control within a safe range. While ensuring steam purity, it simultaneously achieves multiple goals such as stable operation, safety and reliability, and energy saving and consumption reduction, thus realizing the simultaneous optimization of control performance and economic benefits.

[0038] Traditional liquid level control responds to changes in steam dryness in a mechanical manner, adjusting only as needed. This lacks intelligent judgment of operating conditions, leading to frequent and haphazard adjustments, and failing to achieve a refined dynamic balance between ensuring steam quality, pursuing energy conservation, and maintaining system stability. To ensure that each liquid level adjustment is both safe and effective, and with a clear direction, some embodiments of this invention, such as... Figure 4 As shown, step S302 includes: S401. Calculate a first critical value and a second critical value based on the target steam dryness value; the first critical value is equal to the difference between the target steam dryness value and the lower threshold value, and the second critical value is equal to the sum of the target steam dryness value and the upper threshold value, wherein the upper threshold value is greater than the lower threshold value.

[0039] It should be noted that the target steam dryness value Xaim and the lower limit threshold Δ are set in advance. X and upper limit threshold Δ Xm Lower limit threshold Δ X The upper limit threshold Δ is set as a buffer zone for negative fluctuations in steam dryness within the system. Xm This represents a positive excess buffer zone for the system's permissible steam dryness. Specifically, it involves calculating the first critical value (lower limit action threshold). Xdown =Target steam dryness value Xaim - Lower threshold ΔX. Calculate the second critical value (upper action threshold). Xup =Target steam dryness value Xaim + Upper limit threshold Δ Xm The upper limit threshold ΔXm is set to be greater than ΔX, typically 1.5 to 3 times ΔX. For example, if ΔX is 0.4%, then ΔXm can be set to 0.8%.

[0040] S402. Compare the average steam dryness value with the first critical value and the second critical value.

[0041] It should be noted that the average steam dryness value calculated in step S301 should be used as the reference value. Xavg With the first critical value Xdown Second critical value Xup Compare them to determine their quality range. If Xdown ≤ Xavg ≤ Xup The system determines that the steam dryness is within a satisfactory range. The system maintains the current optimal liquid level setpoint to avoid unnecessary adjustments and ensure system stability.

[0042] S403. If the average steam dryness value is less than the first critical value, it is determined that the steam dryness does not meet the standard, and the liquid level reduction amount is calculated according to the target steam dryness value, the lower limit threshold, the average steam dryness value and the downward adjustment optimization gain, and it is determined that the optimal liquid level setting value for the next sampling period is equal to the maximum value of the liquid level lower limit value and the first sum value; the first sum value is equal to the sum value of the current optimal liquid level setting value and the liquid level reduction amount.

[0043] It should be noted that: if Xavg < Xdown, that is, if the average steam dryness , this indicates that the separation effect does not meet the standard, the steam dryness does not meet the standard, and the separation needs to be strengthened. According to the performance deviation, the liquid level reduction amount (the adjustment amount of the liquid level setting value) can be calculated by the following formula: ; where is the average steam dryness, is the lower limit threshold, used to avoid triggering adjustments due to minor fluctuations, Xaim is the target steam dryness value, K low is the downward adjustment optimization gain.

[0044] In this way, the optimal liquid level setting value for the next sampling period is equal to the maximum value of the liquid level lower limit value and the first sum value, that is , to ensure that the optimal liquid level setting value for the next sampling period is not lower than the liquid level lower limit value.

[0045] S404. If the average steam dryness value is greater than the second critical value, it is determined that there is a surplus in steam dryness, and the liquid level increase amount is calculated according to the target steam dryness value, the upper limit threshold, the average steam dryness value and the upward adjustment optimization gain, and it is determined that the optimal liquid level setting value for the next sampling period is equal to the minimum value of the liquid level upper limit value and the second sum value; the second sum value is equal to the sum value of the current optimal liquid level setting value and the liquid level increase amount.

[0046] It should be noted that: if Xavg > Xup, that is, if , this indicates that there is energy-saving potential, and there is a clear and sufficient surplus in steam dryness, and the energy-saving potential can be explored. The optimizer will try to slightly increase the liquid level, and the liquid level increase amount (the adjustment amount of the liquid level setting value) can be calculated by the following formula: ; where is the average steam dryness, Δ Xm is the upper limit threshold, used to ensure that energy conservation is only attempted when there is clearly excess performance, Xaim is the target steam dryness value, Khigh is the upward adjustment optimization gain.

[0047] Thus, the optimal liquid level setpoint for the next sampling period is equal to the minimum of the upper limit of the liquid level and the sum of the two values, i.e. This is to ensure that the optimal liquid level setting value for the next sampling cycle does not exceed the upper limit of the liquid level.

[0048] The optimal liquid level setpoint calculated by the host computer through the above process The data is sent to the lower-level MPC controller (i.e., the slave device). The MPC controller will immediately use this new setting as a target to perform dynamic prediction and optimization again, driving the drain valve to smoothly and quickly transition the liquid level to the new optimal operating point.

[0049] In this embodiment, by introducing dual thresholds (including an upper threshold and a lower threshold) based on scientifically set instrument errors, the system can clearly distinguish between deviations from the operating conditions requiring intervention and negligible measurement fluctuations. This fundamentally eliminates the problems of "not adjusting when it should" or "adjusting when it shouldn't" caused by arbitrary threshold settings in traditional manual operation or simple control. It ensures that each control action has a sufficient and consistent justification, achieving precision and objectivity in the triggering conditions for control decisions. Furthermore, for the two states of substandard and surplus, pre-calibrated downward and upward optimization gains are used for proportional calculation, ensuring that the adjustment amount is proportional to the severity of the problem (deviation). This avoids the under-adjustment or over-adjustment problems that may exist with fixed-step adjustments, and also ensures the consistency of decisions at different time points under the same operating condition, improving the scientific nature and predictability of the control. Furthermore, regardless of the adjustment amount (liquid level increase or decrease) calculated by the optimization algorithm, after calculating the optimal liquid level setpoint, the max / min function and safety boundary are forcibly used. L low , L high By imposing constraints, the final liquid level setpoint will never exceed the safe operating range verified by fluid dynamics simulation and experiments, ensuring that energy-saving exploration or performance improvement will never come at the expense of equipment flow field stability and core separation efficiency. Through S430 and S440, decisive intervention can be made when steam dryness is insufficient, and careful optimization can be performed when there is a surplus of steam dryness. This allows the steam-water separator to operate continuously, stably, reliably, and economically for a long period, maintaining the liquid level near the optimal setpoint, significantly reducing energy consumption while ensuring optimal steam purity.

[0050] Traditional liquid level control suffers from a disconnect between the separation effect and changes in operating conditions due to fixed setpoints and delayed response. To achieve rapid, stable, and accurate tracking of the optimal liquid level setpoint, in some embodiments of this invention, the optimal liquid level setpoint is used as the tracking target. Based on the current liquid level, the inlet steam flow rate, the outlet steam dryness, and the internal pressure, the optimal drain valve opening of the electric drain valve 12 is calculated, including: Based on the current liquid level, the inlet steam flow rate, the outlet steam dryness fraction, and the internal pressure, the predicted liquid level for the next moment is calculated: (1) in, Let k be the current liquid level value at the current time. To predict the liquid level at time k+1, The sampling period is The average cross-sectional area of ​​the gas-water separator 10 within its normal operating liquid level range. The density of the water phase within the steam-water separator 10. Let K be the inlet steam flow rate at time k. Let k be the outlet steam dryness value. The density of saturated water in the steam-water separator 10 at the current operating pressure is given. The flow coefficient of the electric drain valve 12 is... Let k be the optimal drain valve opening of the electric drain valve 12 to be solved at time k. The internal pressure value of the steam-water separator 10 at time k; Using the optimal liquid level setpoint as the tracking target, the optimal drain valve opening is calculated based on the predicted liquid level value, and the liquid level value at the next moment and the optimal drain valve opening satisfy preset constraints: (2) in, and For prediction in the time domain and control in the time domain, The penalty weighting coefficient for changes in the control quantity Set the liquid level value. This represents the magnitude of the change in valve opening between two adjacent future time points. It is a time index variable; the preset constraints include: ; (3) in, To reduce the optimization gain, To optimize the gain, This is the lower limit of the liquid level. This is the upper limit of the liquid level.

[0051] It should be noted that for any assumed optimal drain valve opening K(k), the liquid level L(k+1) at the next moment can be predicted, providing a basis for optimization. The optimal drain valve opening K(k) is calculated using the optimal liquid level setpoint Lset as the tracking target, combined with the above formulas (1) to (3). Among them, the preset constraint conditions defined in formula (3) [ L low , L high ]and[ K min , K max This ensures the safety and physical feasibility of the operation. Within the prediction time domain p (e.g., the next 10-20 cycles), the controller repeatedly calls formula (1) to simulate the trajectory of the future liquid level {L(k+1), L(k+2), ...} under the action of valve openings {K(k), K(k+1), ...} in different sequences. The optimization algorithm (e.g., quadratic programming) finds the sequence that minimizes the objective function value shown in formula (2) among all possible valve action sequences. The objective function consists of two parts: the first term (tracking error) minimizes the deviation between the predicted liquid level and the target Lset to ensure control accuracy. The second term (control penalty) minimizes the valve's own action amplitude ΔK to ensure smooth control and avoid frequent large valve actions. After solving, only the first control action in the optimal sequence is output as the optimal drain valve opening K(k) to the electric drain valve 12. In the next sampling cycle k+1, the system obtains new actual measurement values, refreshes the initial prediction state, and repeats the entire process from S101 to S104 to achieve closed-loop rolling optimization.

[0052] In this embodiment, formula (1) is a multivariate feedforward model that includes flow rate (F), dryness fraction (X), and pressure (P). When the steam load and other operating conditions change, it can predict the impact on the liquid level in advance (such as the increase in water volume caused by the increase in load), and compensate by optimizing the calculation of the optimal drain valve opening K(k). This fundamentally overcomes the drastic fluctuations in liquid level caused by the lag of traditional feedback control. By using formulas (1) to (3), the dynamic change of the optimal liquid level setpoint Lset is tracked, so that the liquid level always serves the current optimal separation efficiency, thereby directly improving the stability and adaptability of steam purity and impurity removal efficiency, and significantly enhancing the system's anti-interference and robustness. Formulas (2) and (3) together ensure that when the system pursues the best process target (tracking Lset), it can automatically avoid unnecessary valve actions and liquid level fluctuations, minimize the ineffective discharge of high-quality condensate, achieve significant energy saving and consumption reduction, and at the same time ensure safety through constraints, achieving the optimal balance between energy saving and process quality. By optimizing the balance between accuracy and stability using formulas (1) to (3), the system achieves the ability to track the optimal process target, making the system respond to major disturbances faster and more smoothly, completely overcoming the violent fluctuations in liquid level, significantly improving control quality, and directly using the preset constraints of liquid level and valve as boundary conditions for the optimization problem, ensuring that each set of control commands solved automatically meets all safety restrictions, eliminating the risk of overshoot and exceeding limits in principle, realizing optimal control with constraints, and changing the control of the steam-water separator 10 from passive response to active control, achieving intelligent operation with high purity, high efficiency, and high stability.

[0053] To improve a safe, reliable, and experimentally sound initial optimization gain, ensuring stable operation of the system under the principle of safety first during initial commissioning, in some embodiments of the present invention, the downward optimization gain is set based on the effective volume and processing flow rate of the steam-water separator 10, and the upward optimization gain is set to 1 / 5 to 1 / 10 of the downward optimization gain.

[0054] It should be noted that: the optimization gain was lowered. This is the proportional coefficient that converts dryness deviation into liquid level adjustment. Adjusting the gain downwards optimizes the process. The sensitivity is inversely proportional to the steady-state sensitivity of the system. The system sensitivity is closely related to the effective volume and flow rate of the steam-water separator 10. For sensitive separators with large flow rates and small effective volumes, changes in liquid level rapidly affect the internal flow field and separation effect, i.e., high sensitivity. Therefore, to avoid control overshoot, a smaller reduction in the optimization gain is required. The initial value is typically set in the lower range of 0.1 to 0.3 (e.g., 0.2). For inertial separators with small flow rates and large effective volumes, the system response is slow and the sensitivity is low. To obtain sufficient adjustment power, a larger reduction in the optimization gain is required. The initial value can be set in the higher range of 0.5 to 1.0 (e.g., 0.8).

[0055] Prioritizing safety and proceeding cautiously with adjustments, to prevent jeopardizing steam quality while exploring energy-saving possibilities, The initial value is set to 1 / 5 to 1 / 10 of the initial value. For example, if If the initial value is set to 0.5, then... The initial value is set to 0.05 to 0.1 to ensure that the magnitude and speed of the energy-saving adjustment are much smaller than the quality-ensuring adjustment.

[0056] Of course, lower the optimization gain With the upward adjustment of the optimized gain Calibration can also be achieved through on-site testing. This involves executing a gain calibration procedure to obtain accurate values ​​during the initial operation of the system. Within the safe liquid level range, a small and constant step change in liquid level is applied. For example, 0.02m. After the system stabilizes, accurately measure the resulting change in outlet steam dryness. Subsequently, the measured sensitivity of the computing system was calculated. Based on this, the optimization gain was updated and adjusted downwards. .in, It is a stability coefficient less than 1, usually taken as 0.5-0.8. Its function is to actively reduce the theoretical gain in order to suppress overshoot, enhance system robustness, ensure that the optimization process proceeds smoothly, and avoid oscillation of the liquid level setpoint due to model mismatch or measurement noise. It will also be updated in the same proportion.

[0057] Of course, lower the optimization gain With the upward adjustment of the optimized gain Adaptive adjustment is also possible. This involves monitoring the response curve of steam dryness after adjusting the liquid level setpoint over a period of time. If the system performance is determined to converge too slowly or exhibit an oscillating trend, the gain can be adjusted downwards by a small, fixed percentage. Fine-tuning allows the system to adapt to the slow decline in equipment performance or long-term changes in operating conditions, maintaining excellent optimized performance at all times.

[0058] In this embodiment, the equipment design specifications (effective volume, processing flow) provide a safe and usable starting point for the system's first power-on, reducing the expert debugging time from several days to several hours, and ensuring that the system can operate stably under the principle of safety first in the initial stage of commissioning.

[0059] How to establish an independent, reliable, and responsive highest-priority safety protection layer for the entire intelligent optimization system to prevent overpressure risks that could endanger the equipment itself during the pursuit of process optimization? In some embodiments of the present invention, it further includes: when the internal pressure value exceeds a preset safety pressure threshold, driving the pressure relief valve 7 to fully open for emergency pressure relief.

[0060] It should be noted that when pressure gauge 6 detects that the internal pressure value P(k) exceeds (is greater than) the preset safety pressure threshold, the lower-level computer will immediately override all other control commands and drive the pressure relief valve 7 to fully open for emergency pressure relief, ensuring equipment safety. The preset safety pressure threshold Pmax is strictly lower than the mechanical design pressure of the steam-water separator 10 and its connected pipelines, while being higher than the system's maximum normal operating pressure. Typically, Pmax is set within the range of 105%-110% of the rated operating pressure to allow for normal pressure fluctuations, but ensures timely action before reaching dangerous pressure. The output signal of pressure gauge 6 (usually a high-reliability, fast-response pressure transmitter) is directly connected in parallel to a dedicated high-speed analog input channel and / or an independent hardware safety relay in the lower-level computer (such as a PLC), ensuring that the hardware circuit can still provide protection even if the main controller experiences a software failure. The lower-level computer has an independent task with an extremely short scan cycle (e.g., 10ms) specifically for comparing the real-time pressure values ​​P(k) and Pmax. Emergency pressure relief valve 7 is triggered to fully open for emergency pressure relief only if the condition P(k) > Pmax is met. To avoid malfunctions caused by pressure fluctuations, a very short confirmation delay (e.g., 20ms) can be set, but this delay is much shorter than the time it takes for the pressure to rise to the dangerous value. Once the condition is met, the safety task will immediately send a highest-priority interrupt signal to the main control task, forcibly interrupting all ongoing routine control activities such as model predictive control optimization calculations and supervisory optimization command issuance.

[0061] The lower-level computer then sends a continuous fully open signal (e.g., 24VDC or 220VAC) to the output point of the pressure relief valve 7. The pressure relief valve 7 is typically a full-bore, quick-opening solenoid or pneumatic valve to ensure sufficient pressure relief capacity. The system enters "emergency pressure relief" mode and triggers the highest level audible and visual alarm. In this mode, the output of the electric drain valve 12 is forcibly locked at its current or safe position to prevent any disruptive operation. After the pressure relief action is executed, the system continuously monitors P(k). Reset is only allowed when P(k) drops to a safe reset threshold Preset (e.g., below the upper limit of normal operating pressure). After the pressure condition is met, the system does not automatically resume normal control; instead, the operator must manually confirm on-site or remotely and reset the alarm. This is to ensure that the cause of the fault is identified. After confirmation, the pressure relief valve 7 closes, the highest priority interrupt is released, and the system restarts from its current actual state, smoothly transitioning to automatic operation.

[0062] In this embodiment, the highest priority is set to trigger the full opening of the pressure relief valve 7 for emergency pressure relief when the condition P(k)>Pmax is met. That is, under any circumstances, whether it is an algorithm calculation error, communication failure, or conventional controller crash, as long as the hardware circuit is intact, the overpressure protection function will be forcibly executed, which greatly enhances the robustness and safety of the entire system in the face of unpredictable failures.

[0063] To establish a set of quantitative, closed-loop adaptive rules, enabling the controller to automatically adjust its core parameters based on the quality of its dynamic response, thereby maintaining optimal control performance and adapting to equipment changes over the long term, in some embodiments of the present invention, such as... Figure 5 As shown, it also includes: S501. Obtain the change data of the outlet steam dryness value after liquid level regulation based on the optimal liquid level setting value.

[0064] It should be noted that after the monitoring and optimization layer adjusts the optimal liquid level setpoint Lset, the system initiates a monitoring window. Starting from the moment Lset undergoes a step change, the system records the real-time changes in the outlet steam dryness value until the system re-enters a steady state.

[0065] S502. Calculate the actual response characteristic quantity based on the changed data; the actual response characteristic quantity includes the actual overshoot and the actual settling time.

[0066] It should be noted that the actual overshoot is calculated by analyzing a complete set of collected change data. The process involves determining the final steady-state value Xsteady (usually the adjusted average outlet steam dryness value), obtaining the maximum outlet steam dryness value deviating from Xsteady during the response process (Xpeak), and calculating the actual overshoot as [(Xpeak - Xsteady) / |ΔLset|] × 100%. Normalization is performed using the change in the liquid level setpoint ΔLset, making the overshoot a relative performance indicator independent of the adjustment range. An allowable error band is set (e.g., ±0.1% × |ΔLset|). Starting from the start of the control response based on the optimal drain valve opening, the time point when the outlet steam dryness value first enters and remains within this error band is searched; this time length is the actual settling time.

[0067] S503. Compare the actual response characteristic quantity with the expected response characteristic quantity; the expected response characteristic quantity includes the expected overshoot and the expected settling time.

[0068] It should be noted that: the expected overshoot is preset, usually set to 0% to 5%, and the expected settling time is preset according to process requirements and system inertia. The calculated actual characteristic quantity is compared with the preset expected response characteristic quantity, that is, to determine whether the actual overshoot > expected overshoot or the actual settling time > expected settling time holds true.

[0069] S504. If the actual overshoot is greater than the expected overshoot, the down-adjustment optimization gain is reduced by a first preset ratio.

[0070] It should be noted that if the actual overshoot exceeds the expected overshoot, it indicates that the system response is excessively oscillating, the control process is not smooth enough, and it may impact subsequent equipment. The optimization gain Klow should be lowered by the first preset ratio (e.g., 0.9, i.e., a 10% reduction). Klow is a key parameter that determines the magnitude of liquid level (and thus affects dryness) adjustment. Reducing Klow means that subsequent optimization algorithms will adjust the liquid level more gradually and gently when correcting dryness deviations, thereby effectively suppressing overshoot and enhancing system stability.

[0071] S505. If the actual adjustment time is greater than the expected adjustment time, and the actual overshoot is less than or equal to the expected overshoot, the down-adjustment optimization gain is increased by a second preset ratio.

[0072] It should be noted that if the actual settling time is greater than the expected settling time and the actual overshoot is less than or equal to the expected overshoot, the optimization gain Klow is increased by the second preset ratio (e.g., 1.1, i.e., an increase of 10%). This makes the system respond more quickly to dryness deviations while ensuring stability, thereby shortening the settling time.

[0073] S506. Based on the updated downward optimization gain, synchronously update the upward optimization gain according to a preset fixed ratio.

[0074] It should be noted that: regardless of how the optimization gain Klow is adjusted, the optimization gain Khigh is immediately updated synchronously according to a preset fixed ratio (such as 1 / 8), ensuring that while the system pursues faster and more stable performance, it does not weaken its safety and conservatism in energy-saving exploration.

[0075] In this embodiment, by periodically comparing the actual response with the expected standard in an objective quantitative manner, the system can automatically diagnose performance degradation trends (such as slower response) and proactively fine-tune parameters for compensation. This allows the system to remain locked near the optimal operating point for a long period, eliminating the tediousness and lag of relying on manual periodic calibration. This achieves closed-loop maintenance and long-term optimization of control performance, overcoming the impact of equipment aging and operating condition drift. Furthermore, by optimizing speed only when stability is achieved (no overshoot) in steps S504 and S505, and prioritizing stability in the event of oscillation, each parameter adjustment is ensured to specifically improve system weaknesses, thereby systematically improving the overall control quality. This not only significantly reduces the maintenance cost throughout the entire lifecycle and enables long-term, efficient, and autonomous operation of the equipment, but also stably delivers on the promises of efficient impurity removal, safe operation, and energy saving throughout the equipment's entire lifecycle, greatly enhancing the system's intelligence level and long-term economic value.

[0076] To better implement the liquid level control method for the steam-water separator in the embodiments of the present invention, based on the liquid level control method for the steam-water separator, the embodiments of the present invention also provide a liquid level control system for the steam-water separator, including: Steam-water separator 10; The data acquisition module includes a level gauge 11 for monitoring the current liquid level inside the steam-water separator 10, a steam flow meter 5 for monitoring the inlet steam flow, a steam dryness meter 9 for monitoring the outlet steam dryness, and a pressure gauge 6 for monitoring the internal pressure. The execution module includes an electric drain valve 12 located at the bottom of the steam-water separator 10; The processor is configured to receive operating parameters from the data acquisition module, including the current liquid level, inlet steam flow rate, outlet steam dryness, and internal pressure of the steam-water separator 10; calculate the optimal liquid level setpoint for the next sampling period based on the target steam dryness and the outlet steam dryness; track the target using the optimal liquid level setpoint, and determine the optimal drain valve opening of the electric drain valve 12 based on the current liquid level, the inlet steam flow rate, the outlet steam dryness, and the internal pressure. The controller is used to send the optimal drain valve opening value to the execution module, so as to drive the electric drain valve 12 to operate according to the optimal drain valve opening value, adjust the drain volume of the steam-water separator 10, and maintain the current liquid level value at the optimal liquid level setting value.

[0077] It should be noted that: See Figure 2The system comprises, in sequence along the steam flow path, a boiler 1, a safety valve 2, a pre-powered electric valve 3, a filter 4, a steam flow meter 5, a steam-water separator 10, a steam dryness meter 9, an outlet electric valve 8, and a steam trap 13. The inlet of the steam-water separator 10 is connected to the steam flow meter 5 via a pipeline, and its clean steam outlet is connected in sequence to the steam dryness meter 9 and the outlet electric valve 8 via pipelines. The bottom drain port of the steam-water separator 10 is connected to the steam trap 13 via a drain pipe, and an electric drain valve 12 is installed on this drain pipe. A level gauge 11 for monitoring the internal liquid level and a pressure gauge 6 for monitoring the internal pressure are installed on the cylinder of the steam-water separator 10. A pressure relief valve 7 is also connected to the vapor phase space of the steam-water separator 10. The system also includes a controller, which is communicatively connected to the level gauge 11, steam flow meter 5, steam dryness meter 9, pressure gauge 6, electric drain valve 12, and pressure relief valve 7. The controller includes a host computer and a slave computer. The slave computer is configured to receive real-time data from the level gauge 11, steam flow meter 5, and pressure gauge 6, and run a model predictive control algorithm to generate and output the optimal drain valve opening to the electric drain valve 12. The host computer is configured to receive and process monitoring data from the steam dryness meter 9, run a supervised optimization algorithm to calculate and send the optimal level setpoint to the slave computer. The slave computer is also configured to trigger the pressure relief valve 7 when the pressure data received from the pressure gauge 6 exceeds a safety threshold. The pre-powered electric valve 3 and the outlet electric valve 8 are opened, and saturated steam is generated from the boiler 1, flowing sequentially through the safety valve 2, the pre-powered electric valve 3, and the filter 4 for preliminary purification. It is then metered by the steam flow meter 5 and enters the core separation space of the steam-water separator 10. Inside the steam-water separator 10, steam achieves efficient steam-water separation through mechanical separation structures (such as cyclones, baffles, and wire mesh). The purified dry steam flows out from the top, is detected online by the steam dryness meter 9, and is then delivered to the downstream user by the outlet electric valve 8. The separated liquid water and impurities settle to the bottom of the separator to form a liquid pool. During normal operation, the electric drain valve 12 continuously discharges the working fluid as needed, and the discharged working fluid is discharged through the steam trap 13. When shutting down, the pre-valve electric valve 3 and the outlet electric valve 8 are closed. The steam flow meter 5 measures the steam flow rate F(k) entering the separator in real time. The level gauge 11 continuously monitors the liquid level L(k) inside the separator. The pressure gauge 6 continuously monitors the internal pressure P(k) of the separator. The steam dryness meter 9 measures the final process parameter—steam dryness X(k)—in real time at the clean steam outlet. The measurement signals from all the above sensors are transmitted in real time to the controller (not shown separately in the figure, usually including a host computer and a slave computer) via cable or industrial bus. The slave computer converts the calculated optimal opening command K(k) into an electrical signal, driving the motor of the electric drain valve 12 to precisely adjust its opening to K(k).By adjusting the sewage discharge rate, the water storage capacity of the liquid pool at the bottom of the separator is changed, thereby causing the actual liquid level L(k) monitored by the level gauge 11 to smoothly and quickly approach the set value Lset, forming a closed-loop control. The signal from the pressure gauge 6 is simultaneously sent to the lower-level machine for independent monitoring. Once the pressure P(k) is detected to exceed the safe pressure threshold Pmax, the lower-level machine will immediately override the normal control commands generated by S102 / S103 and directly send a fully open signal to the pressure relief valve 7 for emergency pressure relief, ensuring the safety of the equipment itself. The safety valve 2 serves as the final mechanical protection for the boiler 1 outlet. Figure 2 As shown, the level gauge 11, electric drain valve 12, and control unit constitute the core of the closed-loop control. The steam dryness meter 9 and steam flow meter 5 serve as important auxiliary monitoring and calibration components. A PLC control station is used as the core lower-level machine, primarily responsible for acquiring data such as level, pressure, and flow, providing safety interlock protection, receiving the level setpoint from the upper-level machine, and quickly calculating and outputting the optimal drain valve opening using a simplified MPC algorithm. The upper-level machine, using an industrial PC, is responsible for running the monitoring, calibration, and setpoint optimization algorithm. It periodically reads the filtered steam dryness value, intelligently calculates based on the dryness deviation, and sends a new optimal level setpoint to the lower-level machine. The level control is implemented in detail as follows: Step 1: System Initialization and Parameter Presetting. Preset key parameters within the controller, including the optimal liquid level control range (including the upper limit of the liquid level). and lower limit of liquid level This range is determined through CFD simulation and experiments based on the specific separator structure, design load, and media characteristics, aiming to balance separation efficiency and wastewater discharge efficiency. The initial value of the optimal liquid level control range ( , The optimal liquid level is determined through the following steps: First, based on the three-dimensional model of the steam-water separator 10, computational fluid dynamics is used to simulate the steam flow field and the motion trajectory of impurity particles under different assumed liquid levels. On the one hand, the velocity distribution of steam on the cross-section of the separation space is evaluated to ensure that the velocity field is uniformly distributed, thus avoiding secondary entrainment caused by local high-speed airflow. On the other hand, a discrete phase model is introduced during the simulation to track the motion trajectory of droplet impurity particles with different diameters (such as 1µm, 5µm, 50µm). The optimal liquid level control range is when the trajectory of most droplet impurity particles terminates at the separator wall or bottom liquid pool, rather than escaping from the outlet with the steam. By statistically analyzing the escape rate of droplets of different sizes at different liquid levels, a liquid level window that can stabilize the flow field and has a low impurity escape rate was initially screened. Subsequently, actual operating condition tests were conducted near this window on an experimental bench. By adjusting the inlet valve to change the steam flow rate into the separator, specific impurity particles (Fe3O4, CuO) were added to the boiler feedwater in proportion to simulate actual operating conditions under different impurity compositions and concentrations. The outlet impurity concentration was measured. Combining the steam dryness and impurity ion concentration data measured under different liquid levels and operating conditions, the liquid level range that can simultaneously meet the steam dryness requirements and impurity removal effect was finally calibrated as the optimal liquid level control range. The MPC model parameters include those based on the cross-sectional area of ​​the separator structure. The design load and medium characteristics were considered, and key parameters in the model were determined through CFD simulation and experiments. Optimizer parameters included the target steam dryness. Dead zone of the monitoring and correction cycle and With optimized gain and The lower limit dead zone The value should be at least twice the maximum permissible measurement error of the steam dryness meter 9. This ensures that the system will only initiate the optimized operation of lowering the liquid level when the dryness is indeed lower than the target value and exceeds the measurement uncertainty range. For applications with extremely high steam quality requirements, this can be further increased to provide a greater safety margin. Upper limit dead zone The value in Further expanding on the basis, it is usually set as 1.5 to 3 times that. Larger This ensures that the system will only cautiously attempt to increase the liquid level to explore energy-saving potential when there is a clear and sufficient margin of steam quality, thus providing a reliable safety buffer for steam quality. Safety parameter: Safe pressure threshold. .

[0078] Step 2: Real-time data acquisition. During system operation, level gauge 11 continuously monitors the current liquid level within the steam-water separator 10. Steam flow meter 5 monitors the steam flow rate entering the separator in real time. The steam dryness meter 9 uses an online dryness sensor based on the conductivity method to monitor the dryness value of the outlet steam in real time. Its principle is to calculate the dryness by measuring the change in the conductivity of the electrolyte in the steam. It has the advantages of fast response, high accuracy, and suitability for high temperature and high pressure environments; pressure gauge 6 continuously monitors the internal pressure of the separator. .

[0079] Step 3: Multi-parameter collaborative control decision-making and execution. The control unit executes the following strategy based on the collected data: Lower-level model predictive dynamic control: The goal of the MPC controller is to drive the actual liquid level. Tracking the liquid level setpoint provided by the host computer layer In the PLC, a simplified, computationally efficient MPC controller is deployed and run. This controller uses the following simplified discrete-time prediction model for rolling optimization: (Formula (1)) In each control cycle, the lower-level machine uses To track the target, solve the following optimization problem and immediately output the optimal drain valve opening; (Formula (2)); ; (Formula (3)) This invention maintains the liquid level within the optimal range, ensuring the stability of the internal flow field of the separator and creating optimal conditions for the sedimentation and capture of impurity particles and water droplets. This results in the continuous output of high-purity steam, effectively protecting downstream equipment from scaling and water hammer damage, and achieving high and stable impurity removal efficiency.

[0080] This invention employs a continuous, on-demand sewage discharge mode, replacing the blindness of traditional timed sewage discharge and the waste of working fluid due to simple liquid level control. It avoids excessive discharge of high-temperature, high-pressure pure condensate, significantly reducing heat loss and water replenishment costs, achieving energy conservation and consumption reduction, with significant savings in both energy and working fluid. Based on a mechanistic model and multivariate feedforward, this invention enables the system to respond faster and more smoothly to load changes, completely overcoming drastic liquid level fluctuations, exhibiting strong anti-interference capabilities and superior control quality. The invention's supervisory optimization layer automatically finds and locks the most economical liquid level setpoint while meeting quality requirements, minimizing the discharge loss of high-quality condensate and achieving significant energy savings. The invention's independent pressure safety interlock protection layer provides the highest level of safety assurance for the smooth operation of the entire impurity removal process, eliminating the risk of overpressure operation and ensuring high safety and reliability.

[0081] The liquid level control system of the steam-water separator provided in the above embodiments can realize the technical solutions described in the above embodiments of the liquid level control method of the steam-water separator. The specific implementation principles of each module or unit can be found in the corresponding content in the above embodiments of the liquid level control method of the steam-water separator, which will not be repeated here.

[0082] like Figure 6 As shown, the present invention also provides an electronic device 600. The electronic device 600 includes a processor 601, a memory 602, and a display 603. Figure 6 Only some components of the electronic device 600 are shown, but it should be understood that it is not required to implement all the components shown, and more or fewer components may be implemented instead.

[0083] In some embodiments, processor 601 may be a central processing unit (CPU), microprocessor, or other data processing chip, used to run program code stored in memory 602 or process data, such as the liquid level control method of the steam-water separator in this invention.

[0084] In some embodiments, processor 601 may be a single server or a group of servers. The server group may be centralized or distributed. In some embodiments, processor 601 may be local or remote. In some embodiments, processor 601 may be implemented on a cloud platform. In one embodiment, the cloud platform may include a private cloud, public cloud, hybrid cloud, community cloud, distributed cloud, intranet, multi-cloud, etc., or any combination thereof.

[0085] In some embodiments, memory 602 may be an internal storage unit of electronic device 600, such as a hard disk or memory of electronic device 600. In other embodiments, memory 602 may also be an external storage device of electronic device 600, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc. equipped on electronic device 600.

[0086] Furthermore, the memory 602 may include both internal storage units of the electronic device 600 and external storage devices. The memory 602 is used to store application software and various types of data installed on the electronic device 600.

[0087] In some embodiments, display 603 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen. Display 603 is used to display information from electronic device 600 and to display a visual user interface. Components 601-603 of electronic device 600 communicate with each other via a system bus.

[0088] In one embodiment, when the processor 601 executes the control program for the steam-water separator in the memory 602, the following steps can be implemented: The operating parameters of the steam-water separator are collected, including the current liquid level, inlet steam flow rate, outlet steam dryness, and internal pressure. Based on the target steam dryness value and the outlet steam dryness value, the optimal liquid level setting value for the next sampling cycle is calculated. Using the optimal liquid level setting as the tracking target, the optimal drain valve opening of the electric drain valve is obtained by calculating the current liquid level value, the inlet steam flow rate, the outlet steam dryness value, and the internal pressure value. The electric drain valve is driven to operate according to the optimal drain valve opening, thereby adjusting the drain volume of the steam-water separator and maintaining the current liquid level at the optimal liquid level setting value.

[0089] It should be understood that when the processor 601 executes the control program for the steam-water separator in the memory 602, in addition to the functions mentioned above, it can also perform other functions, as detailed in the description of the corresponding method embodiments above.

[0090] Furthermore, this embodiment of the invention does not specifically limit the type of electronic device 600 mentioned. Electronic device 600 can be a mobile phone, tablet computer, personal digital assistant (PDA), wearable device, laptop computer, or other portable electronic device. Exemplary embodiments of portable electronic devices include, but are not limited to, portable electronic devices running iOS, Android, Microsoft, or other operating systems. The aforementioned portable electronic device can also be other portable electronic devices, such as a laptop computer with a touch-sensitive surface (e.g., a touch panel). It should also be understood that in some other embodiments of the invention, electronic device 600 may not be a portable electronic device, but rather a desktop computer with a touch-sensitive surface (e.g., a touch panel).

[0091] Accordingly, this application also provides a computer-readable storage medium for storing computer-readable programs or instructions. When the programs or instructions are executed by a processor, they can implement the steps or functions of the liquid level control method for the steam-water separator provided in the above-described method embodiments.

[0092] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware (such as a processor, controller, etc.), and the computer program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0093] The liquid level control method, system, equipment, and medium of the steam-water separator provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for controlling the liquid level in a steam-water separator, characterized in that, include: The operating parameters of the steam-water separator are collected, including the current liquid level, inlet steam flow rate, outlet steam dryness, and internal pressure. Based on the target steam dryness value and the outlet steam dryness value, the optimal liquid level setting value for the next sampling cycle is calculated. Using the optimal liquid level setting as the tracking target, the optimal drain valve opening of the electric drain valve is obtained by calculating the current liquid level value, the inlet steam flow rate, the outlet steam dryness value, and the internal pressure value. The electric drain valve is driven to operate according to the optimal drain valve opening, thereby adjusting the drain volume of the steam-water separator and maintaining the current liquid level at the optimal liquid level setting value.

2. The liquid level control method for a steam-water separator according to claim 1, characterized in that, The calculation of the optimal liquid level setpoint for the next sampling period based on the target steam dryness value and the outlet steam dryness value includes: The average steam dryness value is calculated based on the outlet steam dryness value. Based on the average steam dryness value and the target steam dryness value, the optimal liquid level setting value for the next sampling period is determined; the optimal liquid level setting value is located between the lower limit of the liquid level and the upper limit of the liquid level.

3. The liquid level control method for a steam-water separator according to claim 2, characterized in that, The step of determining the optimal liquid level setpoint for the next sampling period based on the average steam dryness value and the target steam dryness value includes: A first critical value and a second critical value are calculated based on the target steam dryness value; the first critical value is equal to the difference between the target steam dryness value and the lower threshold value, and the second critical value is equal to the sum of the target steam dryness value and the upper threshold value, wherein the upper threshold value is greater than the lower threshold value; Compare the average steam dryness value with the first critical value and the second critical value; If the average steam dryness value is less than the first critical value, it is determined that the steam dryness does not meet the standard. The liquid level reduction amount is calculated based on the target steam dryness value, the lower limit threshold, the average steam dryness value, and the down-adjustment optimization gain. The optimal liquid level setting value for the next sampling period is determined to be equal to the maximum value of the liquid level lower limit value and the first sum value. The first sum value is equal to the sum of the current optimal liquid level setting value and the liquid level reduction amount. If the average steam dryness value is greater than the second critical value, it is determined that there is a surplus in steam dryness. The liquid level adjustment amount is calculated based on the target steam dryness value, the upper limit threshold, the average steam dryness value, and the upward optimization gain. The optimal liquid level setting value for the next sampling period is determined to be equal to the minimum value of the upper limit value and the second sum value. The second sum value is equal to the sum of the current optimal liquid level setting value and the liquid level adjustment amount.

4. The liquid level control method for a steam-water separator according to claim 1, characterized in that, The process of tracking the optimal liquid level setpoint and calculating the optimal drain valve opening of the electric drain valve based on the current liquid level, the inlet steam flow rate, the outlet steam dryness, and the internal pressure includes: Based on the current liquid level, the inlet steam flow rate, the outlet steam dryness fraction, and the internal pressure, the predicted liquid level for the next moment is calculated: ； in, Let k be the current liquid level value at the current time. To predict the liquid level at time k+1, The sampling period is This refers to the average cross-sectional area of ​​the gas-water separator within its normal operating liquid level range. The density of the water phase within the steam-water separator is given. Let K be the inlet steam flow rate at time k. Let k be the outlet steam dryness fraction at time k. The density of saturated water in the steam-water separator at the current operating pressure is given. The flow coefficient of the electric drain valve. Let k be the optimal opening degree of the electric drain valve to be determined at time k. Let k be the internal pressure value of the steam-water separator at time k; Using the optimal liquid level setpoint as the tracking target, the optimal drain valve opening is calculated based on the predicted liquid level value, and the liquid level value at the next moment and the optimal drain valve opening satisfy preset constraints: ； in, and For prediction in the time domain and control in the time domain, The penalty weighting coefficient for changes in the control quantity Set the liquid level value. This represents the magnitude of the change in valve opening between two adjacent future time points. It is a time index variable; the preset constraints include: ； ； in, To reduce the optimization gain, To optimize gain, This is the lower limit of the liquid level. This is the upper limit of the liquid level.

5. The liquid level control method for a steam-water separator according to claim 3, characterized in that, The downward optimization gain is set based on the effective volume and processing flow rate of the gas-water separator, and the upward optimization gain is set to 1 / 5 to 1 / 10 of the downward optimization gain.

6. The liquid level control method for a steam-water separator according to claim 1, characterized in that, Also includes: When the internal pressure value exceeds the preset safety pressure threshold, the pressure relief valve is fully opened to perform emergency pressure relief.

7. The liquid level control method for a steam-water separator according to claim 4, characterized in that, Also includes: Obtain the change data of the outlet steam dryness value after liquid level control based on the optimal liquid level setting value; The actual response characteristic quantity is calculated based on the changed data; The actual response characteristics include the actual overshoot and the actual settling time. Compare the actual response characteristics with the expected response characteristics; The expected response characteristics include the expected overshoot and the expected settling time. If the actual overshoot is greater than the expected overshoot, the down-adjustment optimization gain is reduced by a first preset ratio. If the actual adjustment time is greater than the expected adjustment time, and the actual overshoot is less than or equal to the expected overshoot, the down-adjustment optimization gain is increased by a second preset ratio. Based on the updated downward optimization gain, the upward optimization gain is synchronously updated according to a preset fixed ratio.

8. A liquid level control system for a steam-water separator, characterized in that, include: Steam-water separator; The data acquisition module includes a level gauge for monitoring the current liquid level inside the steam-water separator, a steam flow meter for monitoring the inlet steam flow, a steam dryness meter for monitoring the outlet steam dryness, and a pressure gauge for monitoring the internal pressure. The execution module includes an electric drain valve located at the bottom of the steam-water separator; The processor is configured to receive operating parameters from the data acquisition module, including the current liquid level, inlet steam flow rate, outlet steam dryness, and internal pressure of the steam-water separator; calculate the optimal liquid level setpoint for the next sampling period based on the target steam dryness and the outlet steam dryness; track the target using the optimal liquid level setpoint, and determine the optimal drain valve opening of the electric drain valve based on the current liquid level, the inlet steam flow rate, the outlet steam dryness, and the internal pressure. The controller is used to send the optimal drain valve opening value to the execution module, so as to drive the electric drain valve to operate according to the optimal drain valve opening value, adjust the drain volume of the gas-water separator, and maintain the current liquid level value at the optimal liquid level setting value.

9. An electronic device, characterized in that, Including memory and processor, among which, The memory is used to store programs; The processor, coupled to the memory, is used to execute the program stored in the memory to implement the steps in the liquid level control method of the steam-water separator according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, Used to store computer-readable programs or instructions, which, when executed by a processor, can implement the steps in the liquid level control method of the steam-water separator according to any one of claims 1 to 7.

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