A water mist trapping control system based on a circulating water production line of a coking plant

Abstract

The application discloses a water mist capturing control system based on a circulating water production line of a coking plant and relates to the technical field of water mist capturing.The variable diagnosis module of the application can extract the escape fluctuation degree, water quantity deviation state and clogging tendency value in real time, accurately identify the clogging precursor and capture efficiency decay; the rolling optimization module can dynamically determine the regulation and control range, direction and step length of spraying and air distribution based on the differential pressure change rate and environmental humidity, and generate a cooperative control sequence through differential correction, thereby solving the problem that single parameter adjustment cannot cope with coupled interference; the execution feedback module can analyze the capture effect deviation and correct the state variable cycle by cycle, thereby ensuring that the control strategy continuously adapts to the working condition change; and the backwashing module can actively optimize the control sequence to implement backwashing when the clogging tendency value is abnormal and the differential pressure rises, thereby blocking the accumulation of coke powder. The modules are linked together, and the clogging prevention, water quality standard reaching and long-term stable and efficient operation are realized.

Description

Technical Field

[0001] This invention relates to the field of water mist capture technology, specifically a water mist capture control system based on a coking plant circulating water production line. Background Technology

[0002] In actual coking circulating water production line water mist capture scenarios, water mist carries coke powder and trace organic matter. The blockage of the capture device and the substandard quality of the recovered water are influenced by the coupling of multiple physical fields. The spatial distribution of water mist and pollutants exhibits non-uniform and dynamically changing characteristics. Existing technologies reveal the following shortcomings: First, existing technologies do not couple and quantify the fluctuations in escape droplet concentration, the tendency of coke powder adhesion on the mesh surface, the moisture content deviation, and the rate of pressure difference change. This makes it impossible to match the actual blockage evolution law and the characteristics of capture efficiency decay in the capture area. Consequently, the control range and direction of spray flushing and air distribution rectification lack objective quantitative basis, resulting in severely insufficient boundary precision and difficulty in effectively suppressing coke powder accumulation. Second, existing solutions lack a control mechanism based on dynamic coordination of state variables, pressure difference change rate, and environmental humidity. This prevents the joint adaptive scheduling and coverage optimization of the spray unit and air distribution rectification components. It cannot implement enhanced flushing to eliminate blind spots in high-risk blockage areas, and it is also prone to ineffective spraying and air distribution actions in low-risk areas. Furthermore, the irregular scheduling of multiple actuators leads to large-scale repeated flushing and energy waste, resulting in unreasonable resource allocation.

[0003] Therefore, there is an urgent need for a water mist capture control system that can quantify the capture of state variables, dynamically determine the control range and direction, and achieve coordinated optimization control of spraying and air distribution to solve the above problems. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a water mist capture and control system based on a coking plant circulating water production line. This system solves the problems in the coking circulating water system where water mist carries coke powder and organic matter, leading to easy clogging of the capture device, substandard quality of recycled water, and difficulty in stable and efficient operation due to a lack of coordinated control.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: a water mist capture and control system based on a coking plant circulating water production line, comprising: a capture and purification module for intercepting coke powder particles for gas-liquid separation, and outputting purified water to be recycled, and configured with a spray unit and an air distribution and rectification component.

[0006] The variable diagnosis module is used to diagnose the state variables of the capture area based on the current capture effect data of the capture and purification module.

[0007] The rolling optimization module is used to determine the control range based on state variables, combined with the rate of change of pressure difference and ambient humidity, determine the control direction by combining the capture effect deviation, determine the control step size according to the fluctuation amplitude of state variables, and then correct it with pressure difference difference and humidity difference to generate the control sequence of the spray unit and air distribution rectification component.

[0008] The execution feedback module is used to adjust based on the control sequence, perform trapping effect deviation analysis on a control cycle basis, and correct the state variables.

[0009] The backwashing module is used to optimize the control sequence and backwash the collection and purification module when the state variables and differential pressure change rate meet the set conditions.

[0010] The water recovery module is used to connect the water to be recovered to the suction well for recycling.

[0011] Compared with existing technologies, this invention has the following advantages: The variable diagnosis module extracts escape fluctuations, water volume deviations, and clogging trend values ​​in real time, accurately identifying precursors to clogging and reductions in capture efficiency; the rolling optimization module dynamically determines the control range, direction, and step size of spraying and air distribution based on the differential pressure change rate and ambient humidity, and generates a collaborative control sequence using differential correction, solving the problem that single parameter adjustment cannot cope with coupled interference; the execution feedback module analyzes the capture effect deviation and corrects state variables periodically, ensuring that the control strategy continuously adapts to changes in operating conditions; the backwashing module actively optimizes the control sequence and implements backwashing when the clogging trend value is abnormal and the differential pressure rises, blocking the accumulation of coke powder. The coordinated operation of these modules achieves anti-clogging, water quality compliance, and long-term stable and efficient operation. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the module connection of the water mist capture control system based on the circulating water production line of a coking plant according to the present invention;

[0013] Figure 2 This is a flowchart illustrating the determination of the control range in the water mist capture control system based on the circulating water production line of a coking plant according to the present invention.

[0014] Figure 3 This is a flowchart illustrating the process of determining the control direction in the water mist capture control system based on the circulating water production line of a coking plant, as described in this invention. Detailed Implementation

[0015] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Please refer to the accompanying drawings. Figure 1 The present invention provides a technical solution: a water mist capture and control system based on a coking plant circulating water production line, comprising: a capture and purification module for intercepting coke powder particles for gas-liquid separation, and outputting purified water to be recycled, and configured with a spray unit and an air distribution and rectification component.

[0016] It should be noted that the capture and purification module includes a pre-interception unit and a high-efficiency fog capture unit.

[0017] It should be noted that the air distribution and rectification assembly is installed between the cooling tower's air inlet and the pre-interception unit, and includes an adjustable airflow distribution guide plate. This is used to evenly distribute the hot and humid air entering the tower, reduce localized high-speed jets, and make the airflow velocity field more uniform at the inlet cross-section of the interception unit.

[0018] The pre-interception unit adopts a large-gap grid structure with a grid spacing of 30mm to 50mm, and is installed downstream of the air distribution and rectification assembly and upstream of the high-efficiency fog-collecting unit. It is used to intercept coke powder particles with a diameter larger than a preset threshold (such as 100μm) to prevent large coke powder particles from directly impacting and clogging the subsequent hydrophilic fog-collecting layer.

[0019] The high-efficiency fog-catching unit uses a multi-layer hydrophilic corrugated plate assembly. The surface of the corrugated plates is hydrophilically modified, and the plate spacing is 15mm to 25mm. It is installed downstream of the pre-interception unit, below the fan or air outlet mask. It is used for gas-liquid separation of micron-sized water mist (especially the 5μm to 50μm particle size range). After the mist droplets hit the plate surface, they spread into a liquid film and flow back.

[0020] The spray unit includes multiple sets of high-pressure nozzles. The spray pipeline is arranged upstream of the large-gap grid and the hydrophilic corrugated plate or between them. The water inlet is connected to the return water module and the external industrial water pipeline respectively. During normal spraying, the recycled water provided by the return water module is used first, and the external industrial water is switched during backwashing.

[0021] The variable diagnosis module is used to diagnose the state variables of the capture area based on the current capture effect data of the capture and purification module.

[0022] Because the clogging evolution and collection efficiency decline in the water mist collection area of ​​the coking circulating water production line are coupled with fluctuations in escape droplet concentration, the tendency of coke powder adhesion to the mesh surface, moisture content deviation, and pressure difference change rate, the instantaneous value of a single sensor cannot reflect the true deterioration trend of the collection state. Therefore, it is necessary to construct three types of state variables that can capture the degree of dynamic fluctuation, the steady-state characteristics of deviation, and the cumulative adhesion trend. Specifically, the process of state variable diagnosis is as follows: continuously collect the number concentration of escape droplets in the downstream airflow of the collection area, and form a relative floating window with the measured value of the escape droplet number concentration at the current sampling time as the center and expand to both sides in equal proportions. Count the number of sampling values ​​that fall within the relative floating window from the predetermined number of consecutive sampling values ​​before the current sampling time.

[0023] For example, if the scale is 20%, and the current value is 100, then the window will be [80, 120].

[0024] If the number of sampled values ​​exceeds half of the total number of consecutively predetermined sampled values, the first state variable is set to zero. Otherwise, the direction of change in the number and concentration of escaped droplets between two adjacent sampled values ​​is calculated, and the ratio of the number of times the direction of change changes to the maximum possible number of times the direction of change changes for the consecutively predetermined number of sampled values ​​is calculated. This ratio is then normalized and used as the escape volatility. For example, the consecutively predetermined number is 10.

[0025] The moisture content at the inlet and outlet of the collection area is collected synchronously and the moisture content difference is calculated. The median value of the moisture content difference in all historical data before the current sampling time is obtained as a dynamic benchmark, and the relative deviation between the moisture content difference at the current sampling time and the dynamic benchmark is calculated.

[0026] The relative deviations are accumulated separately for positive and negative values ​​to obtain positive and negative accumulated values. The ratio of the absolute values ​​of the positive and negative accumulated values ​​is calculated and compared with the same ratio at the previous sampling time to obtain the direction of the ratio change. The ratio and the direction of the ratio change at the current sampling time are combined and encoded into a status identifier as the water volume deviation state.

[0027] The light attenuation rate of coke powder attached to the mesh surface set on the surface of the large-gap grid and hydrophilic material is continuously collected, and the relative position of the light attenuation rate of coke powder attached to the mesh surface at each sampling moment with respect to the maximum and minimum values ​​in the historical sampling data of a predetermined time period is recorded.

[0028] If the light attenuation rate of the coke powder attached to the mesh at the current sampling time is higher than the historical maximum value, a positive overshoot event is marked; if the light attenuation rate of the coke powder attached to the mesh at the current sampling time is lower than the historical minimum value, a negative overshoot event is marked.

[0029] The system counts the number of positive and negative overtaking events within a recent predetermined time interval. It calculates the difference between these two counts, and the sum of their values. The ratio of this difference to the sum is then mapped to a predetermined interval as a congestion trend value. For example, the predetermined time interval is 10 minutes, and the range is 0-1.

[0030] It should be noted that for the number concentration of escaped droplets, instantaneous values ​​alone cannot distinguish between normal fluctuations and abnormal escape. Therefore, a relative floating window is used to statistically analyze the density of sampled values ​​within the window. If the density is high, it is considered a steady-state fluctuation (assigned a value of zero). If the density is low, the frequency of change in the direction of change is further calculated to quantify the escape fluctuation. For the moisture content difference, static deviation values ​​are meaningless due to environmental and operating conditions. Therefore, the historical median is used as a dynamic benchmark to calculate the relative deviation, and the positive and negative cumulative ratio and its direction of change are introduced and encoded as the moisture deviation state to identify abnormal states dominated by negative deviation (i.e., the moisture content at the outlet is significantly lower than that at the inlet). For coke powder adhesion on the mesh surface, the light attenuation rate itself has amplitude fluctuations. It is necessary to record the overshoot events through a historical extreme value window, and use the ratio of the difference between the frequencies of positive and negative overshoot events to the sum of the frequencies to map the accumulation trend value to reflect the net trend of adhesion accumulation.

[0031] The escape droplet number concentration is the number of water mist droplets per unit volume in the downstream airflow of the capture area that have escaped without being captured. It is continuously collected using an optical particle counter installed in the downstream pipe. A higher value indicates more water mist is not captured, and a lower capture efficiency.

[0032] Escape volatility is a quantitative value reflecting the degree of fluctuation in the number and concentration of escaped droplets. The value ranges from 0 to 1, with values ​​closer to 1 indicating more severe fluctuations and a more unstable capture state.

[0033] A positive moisture content difference indicates that the outlet moisture content is lower than the inlet moisture content (water mist has been removed), while a negative moisture content difference indicates that the outlet moisture content is higher than the inlet moisture content (abnormal humidification). The median value, as a dynamic benchmark, can resist instantaneous peak interference and reflect the typical deviation level under normal operating conditions.

[0034] The coding method for water volume deviation is as follows: a proportion greater than 1 and increasing indicates positive deviation enhancement, while a proportion less than 1 and decreasing indicates negative deviation dominance. This is used to determine whether the system is in a net dehydration or net humidification state.

[0035] The light attenuation rate of coke powder adhesion on the mesh surface is the ratio of light intensity reduction before and after passing through the collecting mesh surface, reflecting the thickness of the coke powder adhesion. It is measured by light emitters and receivers installed on both sides of the collecting mesh surface, with a value ranging from 0 to 1. The closer to 1, the more severe the adhesion.

[0036] The congestion trend value ranges from 0 to 1. A larger value indicates a stronger net congestion trend, and a value closer to 1 indicates rapid accumulation. The mapping rule is the sum of the ratio and 1, divided by 2.

[0037] This embodiment distinguishes between random fluctuations in the number and concentration of escaped droplets and systemic escape by statistically analyzing the relative floating window and the number of changes in the direction of change, enabling escape fluctuations to accurately indicate precursors to a decline in capture efficiency. By using the cumulative positive and negative ratios of moisture content differences under a dynamic benchmark and their changing direction, the water volume deviation is quantified into a coded state identifier, thereby determining whether the system is in a state dominated by negative deviations (i.e., insufficient purification capacity). By constructing a blockage trend value through the frequency of positive and negative exceedance events within a historical extreme value window, the net accumulation trend of coke powder adhesion is mapped, avoiding misjudgments caused by simple fluctuations in the amplitude of light attenuation rate. The three types of state variables correspond to the gas-liquid-solid three-phase coupling characteristics during the capture process, solving the problem of the lack of coupled quantitative calculations in existing technologies.

[0038] The rolling optimization module is used to determine the control range based on state variables, combined with the rate of change of pressure difference and ambient humidity, determine the control direction by combining the capture effect deviation, determine the control step size according to the fluctuation amplitude of state variables, and then correct it with pressure difference difference and humidity difference to generate the control sequence of the spray unit and air distribution rectification component.

[0039] It should be noted that if the adjustment range of the spray flow rate and the baffle opening remains fixed, it will be unable to adapt to dynamic changes in escape fluctuations, water volume deviations, clogging trends, and ambient humidity. When the state variables are higher than the historical median value, it indicates that the current collection state is worse than the typical level, and it is necessary to adjust upwards based on the current value; conversely, it indicates that the state is better than the historical median, and downward adjustment or even closure is permissible. When the water volume deviation state is dominated by negative deviation, there is a risk of over-dehydration or excessively dry mesh surface, and it is necessary to prevent the spray flow rate from being too low. When the ambient humidity is higher than the historical median value, excessive external humidity may affect gas-liquid separation, and it is necessary to prevent the baffle opening from being too small.

[0040] Based on the above considerations, such as Figure 2 As shown, the process of determining the control range is as follows: extract escape fluctuation, water volume deviation and blockage trend values ​​from the state variables.

[0041] If the escape volatility is greater than the historical median value of the escape volatility, the lower limit of the spray flow rate of the spray unit will be set to the current value of the spray flow rate, and the upper limit will be set to the maximum permissible value of the spray flow rate. Otherwise, the lower limit will be set to zero, and the upper limit will be set to the current value of the spray flow rate.

[0042] If the water flow deviation is dominated by negative deviation, the lower limit of regulation will be raised to the average of the current value of the spray flow rate and the minimum permissible value of the spray flow rate, while the upper limit of the spray flow rate regulation will remain unchanged. Otherwise, the defined regulation range will remain unchanged.

[0043] If the congestion trend value is greater than the historical median value of the congestion trend value, then the lower limit of the deflector opening of the air distribution and rectification component is set to the current value of the deflector opening, and the upper limit is set to the maximum permissible value of the deflector opening. Otherwise, the lower limit of the deflector opening is set to zero, and the upper limit is set to the current value of the deflector opening.

[0044] If the ambient humidity is greater than the historical median value, the lower limit of the deflector opening will be raised to the average of the current deflector opening and the minimum permissible value, while the upper limit of the deflector opening will remain unchanged. Otherwise, the control range will remain unchanged. Ambient humidity refers to the real-time humidity of the environment where the purification module is located.

[0045] This embodiment links the spray flow rate control range with escape fluctuation and water volume deviation, enabling the spray unit to adjust upwards to enhance flushing when the collection condition deteriorates, and downwards to save energy when the condition is good. When the water volume deviation is dominated by negative deviation, the lower control limit is actively raised to prevent excessively low spraying from causing mesh drying or a sharp drop in collection efficiency. For the deflector opening, when the clogging trend value is higher than the historical median, it is forcibly adjusted upwards to enhance air distribution and suppress coke powder adhesion; when the ambient humidity is too high, the lower control limit is raised to prevent the deflector opening from being too small, causing uneven airflow distribution.

[0046] The direction of spray flow rate adjustment should directly respond to the fluctuation of the escape droplet number concentration, while the fluctuation itself cannot directly provide directionality. The difference between the escape fluctuation and its historical median value can reflect whether the current fluctuation state is worsening or improving relative to the typical level, thus determining whether the spray flow rate should be increased to enhance capture or decreased to avoid over-washing. For the air distribution and rectification components, the direction of baffle opening adjustment should be related to the characteristics of the water volume deviation state: when the water volume deviation state is dominated by negative deviation, it indicates that the outlet moisture content is consistently lower than the inlet, posing a risk of excessive dehydration or overly dry mesh surface. In this case, the baffle opening needs to be increased to increase ventilation and improve airflow distribution, avoiding a decrease in capture efficiency due to localized over-drying; conversely, the baffle opening should be decreased to reduce unnecessary air distribution energy consumption.

[0047] Furthermore, such as Figure 3 As shown, the process of determining the control direction based on the deviation of the combined capture effect is as follows: extract the escape fluctuation degree and water volume deviation state from the state variables.

[0048] Calculate the difference between the escape volatility and the median value of the escape volatility at any historical time. If the difference is positive, the spray unit is adjusted to increase the spray flow rate. If the difference is negative, the spray flow rate is decreased. If the difference is zero, the spray flow rate remains unchanged.

[0049] If the water flow deviation is dominated by a negative deviation, the adjustment direction of the air distribution and rectification component is to increase the opening of the guide vane. Otherwise, it is to decrease the opening of the guide vane.

[0050] The capture effect deviation is the difference between the escape volatility and the median value of the escape volatility at historical moments, as well as the water volume deviation state.

[0051] This embodiment directly determines the direction of increase or decrease in spray flow rate by using the sign of the difference between the escape fluctuation and the historical median value. This avoids misjudgments of adjustment direction caused by the lack of directionality in the fluctuation itself, ensuring that the spray action always points to the correct path of increasing when the situation worsens and decreasing when it improves. Simultaneously, it directly determines the direction of increase or decrease in the baffle opening by whether the water volume deviation state is dominated by negative deviation. This allows the air distribution action to proactively increase the opening to improve airflow distribution when the outlet moisture content is consistently low, and decrease the opening to save energy otherwise. This solves the problem of repeated and ineffective adjustments caused by the lack of directional basis in existing technologies.

[0052] Considering that a fixed adjustment step size for the spray flow rate and guide vane opening cannot adapt to changes in the amplitude of state variable fluctuations, a larger step size is needed to quickly respond to deterioration in the capture state when escape volatility and water volume deviation fluctuate drastically; when fluctuations are gentle, a smaller step size should be used to avoid overshoot or oscillation. Therefore, it is necessary to extract a quantitative value that can characterize the amplitude of fluctuations from the state variables. Further, the process of determining the control step size based on the amplitude of state variable fluctuations is as follows: extract escape volatility and water volume deviation from the state variables, calculate the average of the absolute values ​​of the differences between escape volatility and water volume deviation at adjacent sampling times, and take the larger value as the characterization value of the spray fluctuation amplitude.

[0053] The ratio of the spray fluctuation amplitude to the historical average is used as the spray step size adjustment coefficient. This coefficient is multiplied by the base value of the single adjustment step size for the spray unit to obtain the spray control step size. The base value of the single adjustment step size is the spray flow rate change corresponding to the smallest adjustment unit of the spray unit. A spray step size adjustment coefficient greater than 1 indicates that the current fluctuation is greater than the historical average, and the step size should be increased; a coefficient less than 1 indicates that the fluctuation is less than the historical average, and the step size should be decreased.

[0054] Extract the water volume deviation state from the state variables, obtain the total number of times the state of the water volume deviation state changes in a consecutive predetermined number of sampling times before the current sampling time, and divide the total number by the consecutive predetermined number to obtain the wind distribution fluctuation frequency characterization value.

[0055] The ratio of the characteristic value of the air distribution fluctuation frequency to the historical average value is used as the air distribution step size adjustment coefficient. This coefficient is then multiplied by the base value of the single adjustment step size of the deflector to obtain the deflector control step size. An air distribution step size adjustment coefficient greater than 1 indicates that the current fluctuation frequency is higher than the historical average, and the deflector step size should be increased; a coefficient less than 1 indicates that the frequency is lower than the historical average, and the step size should be decreased.

[0056] It should be noted that for spray control, the absolute value of the difference between adjacent moments of escape fluctuation and water volume deviation can reflect the intensity of the fluctuation. The larger the value of the spray fluctuation amplitude characterization value, the more severe the overall fluctuation of the spray-related state. For baffle plate control, the frequency of water volume deviation state changes can reflect the degree of system instability. The value of the air distribution fluctuation frequency characterization value ranges from 0 to 1. The closer it is to 1, the more frequent the water volume deviation state changes, the more unstable the system, and the more frequent the state changes, the higher the fluctuation frequency. The air distribution adjustment step size should be increased.

[0057] In this embodiment, the spray control step size dynamically changes according to the fluctuation amplitude of escape volatility and water volume deviation. When fluctuations are large, the step size increases to quickly suppress further deterioration; when fluctuations are small, the step size decreases for precise adjustment, avoiding slow response or over-adjustment caused by a fixed step size. The air distribution control step size adaptively adjusts according to the frequency of water volume deviation changes; the higher the frequency, the larger the step size, thereby accelerating the air distribution response and improving the system's anti-interference capability. This adaptive step size mechanism, in conjunction with the control range and direction, makes the control sequence of spray and air distribution more adaptable to different operating conditions, improving the timeliness and stability of the capture effect adjustment.

[0058] Since the difference in pressure differential rate (pressure differential difference) reflects the accelerating trend of resistance change before and after the capture and purification module, it can indicate in advance the worsening of blockage or the effectiveness of flushing. The difference in ambient humidity (humidity difference) reflects the direction and magnitude of abrupt changes in humidity around the tower, which has a direct impact on the gas-liquid separation effect. Therefore, the set values ​​of spray flow rate and guide vane opening cannot rely solely on the monotonic recursion of the previous step length; dynamic corrections for pressure differential rate and ambient humidity, as well as the cross-coupling effect between the two, must also be introduced.

[0059] Based on the above reasons, the process of generating the control sequence for the spray unit and the air distribution and rectification component is as follows: Obtain the difference between the differential pressure change rate at the start of the current control cycle and the differential pressure change rate at the start of the previous control cycle, as the differential pressure difference. Obtain the difference between the ambient humidity around the tower at the start of the current control cycle and the ambient humidity around the tower at the start of the previous control cycle, as the humidity difference.

[0060] Obtain the historical median absolute value of the differential pressure, calculate the ratio of the absolute value of the differential pressure to the historical median absolute value, and then multiply it by the base value of the single-cycle spray adjustment step to obtain the absolute value of the spray flow correction value. The sign of the spray flow correction value is the same as that of the differential pressure.

[0061] Obtain the historical median absolute value of the humidity difference, calculate the ratio of the absolute value of the humidity difference to the historical median absolute value, and then multiply it by the base value of the single adjustment step size of the air distribution and rectification component's guide vane to obtain the absolute value of the guide vane opening correction value. The sign of the guide vane opening correction value is the same as the sign of the humidity difference.

[0062] Obtain the spray flow rate setting value at the end of the previous control cycle. Add the spray flow rate correction value and the guide vane opening correction value to the spray flow rate setting value and the guide vane opening setting value at the end of the previous control cycle, respectively, to obtain the spray flow rate setting value and the guide vane opening setting value at the current control step.

[0063] The absolute value of the pressure difference is compared with the absolute value of the humidity difference. If the absolute value of the pressure difference is greater than the absolute value of the humidity difference, the spray flow rate setting value at the current control step is increased by a spray cross correction amount. The spray cross correction amount is the absolute value of the humidity difference multiplied by the cross influence coefficient of the spray unit, while keeping the guide vane opening setting value at the current control step unchanged.

[0064] If the absolute value of the humidity difference is greater than the absolute value of the pressure difference, then the deflector opening setting value at the current control step time will be increased by a deflector cross correction amount. The deflector cross correction amount is the absolute value of the pressure difference multiplied by the cross influence coefficient of the air distribution and rectification component, while keeping the spray flow setting value at the current control step time unchanged.

[0065] If the absolute value of the humidity difference is equal to the absolute value of the pressure difference, then the spray flow rate setting and the guide vane opening setting at the current control step time are kept unchanged.

[0066] The spray flow rate setpoint and the guide vane opening setpoint at the current control step are output as the content of the current control step in the control sequence, and the above steps are repeated according to the control cycle to generate the setpoint for each control step.

[0067] It should be noted that the cross-influence coefficient reflects the degree of coupling between humidity changes and spray demand or pressure difference changes and air distribution demand. It is dimensionless; a larger value indicates stronger cross-compensation. The cross-influence coefficient for the spray unit ranges from 0.05 to 0.15, and is specifically calibrated as follows: In the actual operation of the coking plant's circulating water production line, keeping the opening of the air distribution and rectification components constant, the ambient humidity is changed by ±10%RH in a step manner. The additional correction amount required for the spray flow rate is recorded, and the cross-influence coefficient is obtained by fitting the data. The cross-influence coefficient for the air distribution and rectification components ranges from 0.02 to 0.10, and the calibration method is similar.

[0068] This embodiment dynamically corrects the setpoints of spray flow rate and guide vane opening through differential pressure and humidity analysis, enabling the control sequence to respond to changes in resistance and sudden changes in ambient humidity, avoiding lag in adjustment. A cross-correction mechanism is introduced: the spray cross-correction amount is increased when differential pressure dominates, and the guide vane cross-correction amount is increased when humidity dominates. This achieves coupling compensation between spraying and air distribution, preventing the exacerbation of adverse changes in one variable due to single-variable adjustment. The final generated control sequence is recursively applied according to the control cycle, allowing spraying and air distribution to adapt collaboratively to dynamic changes in the capture conditions, improving anti-interference capability and control accuracy.

[0069] The execution feedback module is used to adjust based on the control sequence, perform trapping effect deviation analysis on a control cycle basis, and correct the state variables. Correcting the state variables means recalculating the state variables.

[0070] After the actual control cycle ends, the measured escape droplet number concentration and light attenuation rate may still deviate from the target values. The amplitude of a single deviation cannot fully reflect the degree of anomaly in the system, and the deviation may be random fluctuation or systematic continuous drift. Therefore, it is necessary to normalize the two deviations separately and calculate the sum of squares to quantify the overall deviation intensity, and at the same time calculate the algebraic sum to determine the direction of the deviation. Specifically, the process of conducting trapping effect deviation analysis is as follows: after the end of each control cycle, collect the average value of the actual measured escape droplet number concentration, the average value of the difference between inlet and outlet moisture content, and the average value of the light attenuation rate of coke powder adhering to the mesh surface within the current cycle, which are respectively used as the actual escape value, the actual moisture content difference, and the actual light attenuation rate.

[0071] Calculate the first deviation between the actual escape value and the historical median of escape fluctuation, and the second deviation between the actual optical attenuation rate and the historical median of optical attenuation rate.

[0072] The first and second deviations are normalized according to their respective historical extreme value ranges to obtain two relative deviation values. The sum of the squares of the two relative deviation values ​​is calculated as the comprehensive deviation energy. At the same time, the algebraic sum of the two relative deviation values ​​is calculated as the comprehensive deviation net direction.

[0073] Obtain the comprehensive deviation energy sequence and comprehensive deviation net direction sequence for three consecutive control cycles. Determine whether the comprehensive deviation energy sequence is monotonically increasing and whether the comprehensive deviation net direction sequence maintains the same sign. If so, the deviation is determined to be a systematic and continuous deviation, a feedback correction command is generated, and state variable correction is performed. Otherwise, the deviation is determined to be a random fluctuation deviation, no feedback correction command is generated, and no state variable correction is performed.

[0074] The overall deviation energy is always non-negative; a larger value indicates a greater overall deviation intensity across multiple dimensions. The net direction of the overall deviation can be positive or negative; a positive value indicates an overall positive deviation, and a negative value indicates an overall negative deviation.

[0075] This embodiment reduces the complexity of deviation analysis by normalizing and fusing two sets of deviations into a comprehensive deviation energy and a comprehensive deviation net direction, thus compressing the multidimensional trapping effect deviation into two identifiable feature quantities. Through trend judgment over three consecutive control cycles, it can effectively identify systemic persistent deviations requiring intervention while filtering out random fluctuations. When a systemic deviation is identified, a feedback correction command is generated and the state variables are corrected. This allows subsequent control cycles to recalculate the control range, direction, and step size based on the corrected state variables, forming a closed-loop adaptive adjustment and improving the robustness and accuracy of the control system.

[0076] The backwashing module is used to optimize the control sequence and backwash the collection and purification module when the state variables and differential pressure change rate meet the set conditions.

[0077] It should be noted that backflushing interrupts the normal collection process and consumes flushing media, so it should not be triggered frequently, nor should it be performed only when a single indicator is abnormal. Therefore, multiple conditions need to be combined to ensure that backflushing is only initiated when there is a clear trend of clogging, the pressure differential worsens, and the collection effect is abnormal.

[0078] The specific setting conditions are as follows: Condition 1: The congestion trend value is greater than the median value of the congestion trend value in all historical moments for three consecutive control cycles, and the value of the congestion trend value in the current control cycle is greater than the value in the previous control cycle.

[0079] Condition 2: The rate of change of differential pressure before and after the capture and purification module is positive in the current control cycle, and the absolute value of the rate of change of differential pressure is greater than the average value of the absolute value of the rate of change of differential pressure at all historical moments.

[0080] Condition 3: The escape volatility value in the current control period is greater than the median value of escape volatility in all historical periods, or the water volume deviation state is in a state dominated by negative deviation.

[0081] It should be noted that the optimized control sequence includes: opening the high-pressure nozzle groups of the spray unit one by one in sequence from upstream to downstream, with each group of nozzles rinsing for 15 to 30 seconds, and the rinsing pressure set to 1.5 to 2.0 times the normal spray pressure. During the entire backwashing process, the opening of the air distribution rectifier component guide plate is forcibly adjusted to more than 80% of the maximum permissible value. After the backwashing is completed, the original control sequence is restored.

[0082] Condition one requires that the clogging trend value be higher than the historical median for three consecutive periods and still rising, to rule out instantaneous fluctuations and confirm continuous coke dust accumulation. Condition two requires that the differential pressure change rate be positive and the magnitude exceed the historical average absolute value, indicating that the resistance is accelerating and clogging is occurring. Condition three requires that the escape volatility be higher than the historical median or that the water volume deviation state be dominated by negative deviation; the former reflects a decline in capture efficiency, and the latter reflects the risk of excessive dryness. Only when all three conditions are met simultaneously is it determined to be a severe state requiring backwashing, thereby triggering the optimized control sequence to execute backwashing.

[0083] This embodiment constructs a multi-condition jointly triggered backwashing start-up mechanism by comparing the continuous periodic values ​​of the clogging trend, judging the positive amplitude of the differential pressure change rate, and using the escape fluctuation or water volume deviation as auxiliary verification. This effectively avoids false backwashing caused by occasional fluctuations in a single parameter. The combination of continuous accumulation verification in condition one, resistance acceleration evidence in condition two, and capture failure indicators in condition three can accurately identify the operating conditions in which the interception unit and the mist collection unit truly require backwashing. It proactively intervenes before the accumulation of coke powder causes permanent blockage, while reducing unnecessary flushing actions, extending the life of the device, and reducing energy consumption.

[0084] The water return module is used to connect the water to be recycled to the suction well for recycling. The water to be recycled is connected to the suction well, and after sedimentation or filtration, it is used as the makeup water source for the spray unit. During backwashing, the spray unit preferentially uses external industrial water or deeply treated recycled water to avoid secondary pollution.

[0085] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0086] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0087] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0088] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0089] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A water mist capture and control system based on a coking plant circulating water production line, characterized in that, include: The capture and purification module is used to intercept coke powder particles for gas-liquid separation, and outputs purified water to be recycled. It is equipped with a spray unit and an air distribution and rectification component. The variable diagnosis module is used to diagnose the state variables of the capture area based on the current capture effect data of the capture and purification module. The rolling optimization module is used to determine the control range based on state variables, combined with the rate of change of pressure difference and ambient humidity, determine the control direction by combining the capture effect deviation, determine the control step size according to the fluctuation amplitude of state variables, and then correct it with pressure difference difference and humidity difference to generate the control sequence of the spray unit and air distribution rectification component; ambient humidity refers to the real-time humidity of the environment where the capture and purification module is located; pressure difference difference is the difference of the rate of change of pressure difference, reflecting the accelerating trend of the resistance change before and after the capture and purification module; The execution feedback module is used to adjust based on the control sequence, perform trapping effect deviation analysis on a control cycle basis, and correct the state variables. The backwashing module is used to optimize the control sequence and backwash the collection and purification module when the state variables and differential pressure change rate meet the set conditions. The water recovery module is used to connect the water to be recycled to the suction well for recycling; The process of performing state variable diagnosis is as follows: Based on the number and concentration of escaped droplets, a floating window is constructed by proportionally expanding the current value as the center, and the number of historical sampled values ​​falling within the floating window is counted. If the number accounts for more than half of the total number of historical sampled values ​​counted, the escape volatility is assigned to zero. Otherwise, the ratio of the number of changes in the direction of change of adjacent sampled values ​​to the maximum possible number of changes is calculated, normalized, and used as the escape volatility. Calculate the difference between the inlet and outlet moisture content, obtain the current relative deviation based on the historical median value, accumulate the positive and negative values ​​separately to obtain the cumulative positive and negative values, calculate the ratio of the absolute values ​​of the cumulative positive and negative values, and encode the ratio and the direction of the ratio change at the previous moment as the water volume deviation state. Based on the light attenuation rate of coke powder attached to the mesh surface, the number of positive overtaking events and the number of negative overtaking events are counted within a predetermined time interval. The difference between the number of positive overtaking events and the number of negative overtaking events, and the sum of the number of positive overtaking events and the number of negative overtaking events are calculated. The ratio of the difference to the sum is mapped to the predetermined interval as the congestion trend value. The process of determining the scope of regulation is as follows: Extract escape volatility, water volume deviation, and blockage trend values ​​from the state variables; The spray flow rate control range of the spray unit is determined based on the escape volatility and the median value of escape volatility at historical moments, whether the water volume deviation state is in a negative deviation-dominated state, and the positive or negative sign of the differential pressure change rate. The air distribution and rectification component's guide vane opening range is determined based on the blockage trend value and the median value of the blockage trend value at historical times, and the ambient humidity and the median value of the ambient humidity at historical times. The process of determining the control direction based on the deviation of the combined capture effect is as follows: Extract escape volatility and water volume deviation from the state variables; Calculate the difference between the escape volatility and the median value of the escape volatility at historical time. If the difference is positive, the control direction of the spray unit is to increase the spray flow rate; if it is negative, the spray flow rate is to decrease; if it is zero, the spray flow rate is kept constant. If the water volume deviation state is dominated by negative deviation, the adjustment direction of the air distribution and rectification component is to increase the opening of the guide vane; otherwise, it is to decrease the opening of the guide vane. The process of determining the control step size based on the fluctuation amplitude of the state variable is as follows: Escape fluctuation and water volume deviation are extracted from the state variables. The average absolute value of the difference between escape fluctuation and the average absolute value of the difference between water volume deviation at adjacent sampling times are calculated respectively. The larger value is taken as the characterization value of the spray fluctuation amplitude. Calculate the ratio of the spray fluctuation amplitude characterization value to the historical average value, and then multiply it by the base value of the spray unit's single spray adjustment step size to obtain the spray control step size; Extract the water volume deviation state from the state variables, count the total number of state changes within a predetermined number of consecutive sampling times before the current sampling time, and divide by the total number of sampling points to obtain the wind distribution fluctuation frequency characterization value. The ratio of the frequency fluctuation characterization value to the historical average value is calculated, and multiplied by the base value of the single adjustment step size of the deflector to obtain the deflector control step size.

2. The water mist capture and control system based on a coking plant circulating water production line according to claim 1, characterized in that, The process of determining the control range of the spray unit is as follows: If the escape volatility is greater than the median value of the escape volatility at any historical time, then the lower limit of the spray flow rate of the spray unit will be set to the current value, and the upper limit will be set to the maximum permissible value. Otherwise, set the lower limit of regulation to zero and the upper limit of regulation to the current value; If the water volume deviation state is dominated by negative deviation, the lower limit of regulation will be raised to the average of the current value and the minimum allowable value, while the upper limit of regulation of the sprinkler flow rate will remain unchanged. Otherwise, the established range of regulation should remain unchanged; If the rate of change of differential pressure is positive, the lower limit of regulation will be raised to the current value, while the upper limit of regulation will remain unchanged. If the value is negative, no correction is made.

3. The water mist capture and control system based on a coking plant circulating water production line according to claim 1, characterized in that, The process of determining the control range of the air distribution and rectification components is as follows: If the congestion trend value is greater than the median value of the congestion trend value at a historical time, then the lower limit of the control of the baffle opening of the air distribution and rectification component will be set to the current value, and the upper limit will be set to the maximum permissible value. Otherwise, set the lower limit of regulation to zero and the upper limit of regulation to the current value; If the ambient humidity is greater than the historical median value, the lower limit of regulation will be raised to the average of the current value and the minimum permissible value, while the upper limit of regulation will remain unchanged; otherwise, the regulation range will remain unchanged.

4. The water mist capture and control system based on a coking plant circulating water production line according to claim 1, characterized in that, The process of generating the control sequence for the spray unit and the air distribution and rectification assembly is as follows: Based on the absolute values ​​of the pressure difference and humidity difference, the absolute values ​​of the spray flow correction value and the absolute values ​​of the guide vane opening correction value are calculated respectively. These are then superimposed with the spray flow setting value and guide vane opening setting value at the end of the previous control cycle to obtain the spray flow setting value and guide vane opening setting value at the current control step. Based on the relationship between the absolute values ​​of the pressure difference and the humidity difference, the spray flow rate setpoint and the guide vane opening setpoint at the current control step are corrected and then used as the output of the current control step in the control sequence.

5. A water mist capture and control system based on a coking plant circulating water production line according to claim 1, characterized in that, The process of performing trapping effect deviation analysis is as follows: Calculate the first deviation between the actual escape value and the historical median value of escape fluctuation, and the second deviation between the actual optical attenuation rate and the historical median value of optical attenuation rate, respectively. The first and second deviations are normalized according to their respective historical extreme value ranges to obtain two relative deviation values. The sum of the squares of the two relative deviation values ​​is calculated as the comprehensive deviation energy. At the same time, the algebraic sum of the two relative deviation values ​​is calculated as the comprehensive deviation net direction. Obtain the comprehensive deviation energy sequence and comprehensive deviation net direction sequence for three consecutive control cycles. Determine whether the comprehensive deviation energy sequence is monotonically increasing and whether the comprehensive deviation net direction sequence maintains the same sign. If so, perform state variable correction; otherwise, do not perform state variable correction.

6. A water mist capture and control system based on a coking plant circulating water production line according to claim 1, characterized in that, The conditions are set as follows: Condition 1: The backlog trend value is greater than the median value of the backlog trend value for three consecutive control periods, and the value of the backlog trend value in the current control period is greater than the value in the previous control period. Condition 2: The rate of change of differential pressure before and after the capture and purification module is positive in the current control cycle, and the absolute value of the rate of change of differential pressure is greater than the average value of the absolute value of the rate of change of differential pressure at all historical moments. Condition 3: The escape volatility value in the current control period is greater than the median value of escape volatility in all historical periods, or the water volume deviation state is in a state dominated by negative deviation.

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