Method and device for measuring and calculating on-way resistance of flue

Abstract

The invention discloses a method and a device for measuring and calculating on-way resistance of a flue, and relates to the technical field of flue resistance measurement, and the method comprises the following steps: presetting a plurality of sets of combined switching pressure measuring devices based on the whole process of an industrial flue; each set of combined switching pressure measuring device comprises a measuring element main body, at least one set of pressure sampling switching execution unit distributed at a preset flue on-way sampling port, and a controller; the controller receives pressure disturbance from a preset flue on-way starting section, the pressure sampling switching execution unit is switched section by section according to the preset initial flow speed, an initial on-way resistance time sequence data packet and a corresponding initial switching time interval are obtained, the standard flow speed and the switching interval are obtained through continuous multi-round data decomposition fitting, and the standard flow speed and the switching interval are obtained. Therefore, the flue can be accurately switched along the way based on the standard flow rate. According to the method, the credibility of the simulation model can be improved, the optimization prediction precision of the flue flow field is improved, and the flue local resistance change and fault accurate positioning are dynamically identified based on actual working conditions.

Description

Technical Field

[0001] This invention relates to the field of data transmission technology for flue friction resistance measurement devices, and in particular to a method and device for measuring flue friction resistance. Background Technology

[0002] Accurate measurement of the resistance in the tail flue of a thermal power plant boiler (including sections such as economizer, air preheater, and dust collector) is crucial for optimizing unit load output and is a necessary means to prevent large-scale blockages and collapses. However, currently, many companies use production data sampling for numerical simulation to identify fly ash deposition characteristics and obtain flue flow field optimization and predictive control information. Existing technologies face three major bottlenecks:

[0003] 1. Manual segmented measurement:

[0004] Although it can be detected point by point during operation through preset test holes, the data acquisition span is too long (more than 2 hours for a 100-meter flue), which leads to operating condition drift; the test hole blockage rate is high, and some need to be stopped for unblocking, resulting in low actual usability; the manual reading error is ±5Pa, and the single-point repeatability error is even higher under high temperature turbulence.

[0005] 2. Fixed sparse measuring points:

[0006] Industrial sites rely on DCS systems with fixed measuring points (spacing > 50m), which cannot capture sudden changes in local resistance (such as ash blockage in a single pipe); electrical clock synchronization ≠ physical synchronization of the flow field. The transmission time lag of flue gas microparticles from the inlet to the tail is usually greater than 6s per 100 meters. The tail data is actually the response of the inlet conditions in the previous period, which leads to the distortion of the physical meaning of resistance calculation.

[0007] 3. Limitations of valve group switching technology:

[0008] Limited to laboratory scenarios, but not applied to full-process monitoring of industrial flues; its engineering shortcomings lie in the inability to determine the switching cycle and its mismatch with the flow rate.

[0009] In summary, the resistance data obtained by existing production data sampling methods are actually the result of piecing together micro-clusters from different times and different flow fields. This leads to problems such as decreased reliability of simulation models, easy loss of key features, and failure of inference. Consequently, the resistance mutation point location error of production process systems that rely on model prediction is large, and the identification of flue blockage is highly delayed. This not only delays the early handling of accidents, but also results in a large loss of soot blowing optimization efficiency and insufficient release of load potential. Summary of the Invention

[0010] The main objective of this invention is to overcome the aforementioned deficiencies in the prior art and propose a method and apparatus for calculating the friction resistance of a flue. This method involves arranging multiple sets of combined switching pressure measuring devices, including a main measuring element, a pressure sampling switching execution unit, and a controller, in series along the entire flue. Based on actual changes in the working conditions of the flue fluid, the sampling data is precisely modulated to assist in the inversion and optimization analysis of the fly ash deposition process in the three-dimensional flow field of the flue. This improves the reliability of the simulation model, enhances the accuracy of flue flow field optimization prediction, and dynamically identifies local resistance changes and accurately locates faults in the flue based on actual working conditions.

[0011] The present invention adopts the following technical solution:

[0012] On the one hand, a method for calculating the friction resistance along a flue is based on the entire length of an industrial flue, with one or more sets of combined switching pressure measuring devices pre-set; each set of combined switching pressure measuring devices includes a first measuring element body, a second measuring element body, at least one set of pressure sampling switching execution units distributed at the pre-set sampling ports along the flue, and a controller, wherein the first measuring element body is used to measure the pressure at the beginning of the pre-set flue, and the second measuring element body is used to measure the pressure in the measuring sampling pipeline where each pressure sampling switching execution unit is located;

[0013] The method for the controller to calculate the friction resistance along the flue includes:

[0014] It receives pressure disturbances from the preset starting section of the flue gas duct and adjusts them according to the preset initial flow velocity of each measurement and sampling pipeline. The pressure sampling switching execution unit switches segment by segment, and obtains the initial friction loss timing data packet based on the pressure disturbance, time delay, and pressure deviation of each measurement sampling pipeline. ;

[0015] Initial friction loss timing data packets Decomposition is performed to obtain the initial true velocity distribution along the friction resistance. ;

[0016] Based on the initial true flow velocity distribution Calculate the initial switching time interval for each pressure sampling switching execution unit. ;

[0017] Based on the initial switching time interval, the preset flue is controlled to undergo multiple pressure disturbances. By comparing multiple data points of the step pressure values ​​in each measurement and sampling pipeline, the true flow velocity distribution is obtained. By combining the pressure, temperature, flow rate, and correction factor of the flue gas / steam in the flue before pressure disturbance, a set of correction factor-standard step pressure correlation parameters for each measurement sampling pipeline under different operating conditions is obtained. ;

[0018] Based on the correction factor-standard step pressure correlation parameter set and the actual flow velocity distribution Perform fitting to obtain the corrected flow rate-switching interval parameter { After multiple fitting iterations, the corrected flow rate-switching interval parameters of each measurement sampling pipeline that meet the preset convergence conditions are obtained and used as the standard flow rate-switching interval parameters.

[0019] Based on the standard flow rate-switching interval parameters of each measurement sampling pipeline, a set of switching instruction strategies for each measurement sampling pipeline is formed in the controller. When the controller detects a pressure disturbance at the beginning of the flue, it triggers different switching interval parameters according to its operating conditions and outputs switching instructions for each measurement sampling pipeline. The controller obtains the received measurement step pressure value, marks its time according to the corrected flow rate, and marks the time delay and pressure deviation of each measurement sampling pipeline.

[0020] Pressure disturbances, operating conditions, step pressure values ​​and marking times, time delays and pressure deviations of each measurement sampling pipeline are stored in the database to form a multidimensional data package for time-series measurement of flue resistance.

[0021] Preferably, the system receives pressure disturbances from the preset initial section of the flue gas duct, switches the pressure sampling switching execution unit segment by segment according to the preset initial flow velocity of each measurement sampling pipeline, and obtains the initial friction resistance timing data packet based on the pressure disturbances, time delays, and pressure deviations of each measurement sampling pipeline, as follows:

[0022] Based on the total length of each measurement sampling pipeline along the preset flue gas path and the corresponding preset initial flow velocity The ratio is used to obtain the corresponding reference delay;

[0023] The pressure disturbance and its duration along the preset flue gas duct's initial section are marked. Based on the reference time delay of each measurement sampling pipeline, the pressure sampling switching execution unit of each measurement sampling pipeline along the preset flue gas duct section is sequentially activated to continuously measure the pressure value of each measurement sampling pipeline. The time of the first step pressure value of each measurement sampling pipeline is marked to obtain the initial actual time delay of each measurement sampling pipeline. Based on the first step pressure value and the initial actual time delay of each measurement sampling pipeline, a set of initial friction resistance timing data packets is obtained. Each set of initial friction resistance timing data packets... Includes measurement timing data packets from the first measurement sampling line to the last measurement sampling line. These are the initial pressure, step time, pressure difference between the initial segment and the first to the Mth pressure channels, and the time interval between the initial segment and the pressure sampling switching execution unit between the first segment and the first to the Mth pressure channels. The time interval is the initial actual delay.

[0024] Preferably, the initial true velocity distribution along the friction resistance. It is expressed as follows:

[0025] ;

[0026] in, Let m be the total length of the sampling pipeline for the m-th measurement. , Indicates the total number of measurement sampling pipelines; The initial actual time delay of the m-th channel; the total length of the m-th channel measurement sampling pipeline includes the distance between the sampling port of the m-th channel measurement sampling pipeline and the flue distance of the preset flue starting section, as well as the length of the m-th channel measurement sampling pipeline.

[0027] Preferably, the initial switching time interval , means as follows:

[0028] ;

[0029] in, This represents the time delay scaling factor for the m-th measurement sampling pipeline.

[0030] Preferably, by combining the pressure, temperature, flow rate, and correction factor of the flue gas / steam in the flue before pressure disturbance, a set of correction factor-standard step pressure correlation parameters for each measurement sampling pipeline under different operating conditions is obtained. The details are as follows:

[0031] ;

[0032] in, , representing the initial association parameters, , and These represent the flue gas pressure, temperature, and flow rate within the flue before the disturbance, respectively. , and They respectively represent based on , and Preset correction factor; This represents the set of correction factor-standard step pressure correlation parameters from the previous iteration; This indicates the corrected flow rate from the previous iteration; .

[0033] Preferably, based on the correction factor-standard step pressure correlation parameter set and the actual flow velocity distribution Perform fitting to obtain the corrected flow rate-switching interval parameter { Specifically, it includes:

[0034] Fitted Corrected Flow Rate ,as follows:

[0035] ;

[0036] in, This represents the actual flow velocity distribution in the previous iteration;

[0037] Based on the total length of each measurement sampling pipeline along the preset flue gas path and the corresponding calibration flow velocity The ratio is used to obtain the corresponding switching interval parameter. .

[0038] Preferably, when the preset convergence condition is the same operating parameters, in a perturbation fitting process with more than a preset number of perturbations, with a switching time interval deviation less than a preset time deviation threshold, the deviation of the measured step pressure value is less than a preset pressure deviation threshold, and the corrected flow velocity and the actual flow velocity distribution satisfy the following:

[0039] ;

[0040] in, This represents the actual velocity distribution in this iteration; The corrected flow rate of the previous iteration is indicated; the same operating condition parameters refer to the fact that the pressure, temperature and flow rate deviations of the flue gas / steam in the flue before the pressure disturbance are all less than the corresponding preset thresholds; This represents the minimum threshold for flow rate change.

[0041] Preferably, the method for calculating the friction resistance along the flue further includes: adjusting the number of the main body of the second measuring element based on the correction flow rate-switching interval parameter of each measuring sampling pipeline during multiple fitting processes.

[0042] Preferably, each pressure sampling switching execution unit is a two-way valve or a three-way valve; when it is a two-way valve, the first path is connected to the sampling port and the second path is connected to the main body of the second measuring element; when it is a three-way valve, the first path is connected to the sampling port, the second path is connected to the main body of the second measuring element, and the third path is connected to the compressed air purging pipe, so that when the resistance of the measuring sampling pipe is found to be abnormal, the corresponding purging signal is triggered to control the compressed air to be introduced.

[0043] On the other hand, a device for calculating the friction resistance along a flue includes: one or more combined switching pressure measuring devices; each combined switching pressure measuring device includes a first measuring element body, a second measuring element body, at least one set of pressure sampling switching execution units distributed at preset flue friction sampling ports, and a controller, wherein the first measuring element body is used to measure the pressure of the preset flue friction starting section, the second measuring element body is used to measure the pressure of the measurement sampling pipeline where each pressure sampling switching execution unit is located; the controller is used to execute the calculation method.

[0044] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0045] (1) Based on the entire industrial flue, the present invention pre-sets one or more combined switching pressure measurement devices. Based on the data collected by the combined switching pressure measurement devices, the standard flow rate-switching interval parameters of each measurement sampling pipeline are obtained, and a set of switching command strategies for each measurement sampling pipeline is formed. When the pressure disturbance at the beginning of the flue is detected, different switching interval parameters are triggered according to its working condition, and the switching command of each measurement sampling pipeline is output. The pressure disturbance, working condition, step pressure value and the time, delay and pressure deviation of the marking are stored in the database to form a multi-dimensional data package of flue resistance time series measurement. Based on the actual flue working condition changes, the sampling data is accurately modulated to assist in the inversion and optimization analysis of the fly ash deposition process of the three-dimensional flow field of the flue. It can improve the credibility of the simulation model, improve the accuracy of flue flow field optimization prediction, and dynamically identify the local resistance changes and fault location of the flue based on the actual working condition.

[0046] (2) Each pressure sampling switching execution unit of the present invention can be connected to a compressed air purging pipe so that when the resistance of the measurement sampling pipeline is abnormally calculated, the corresponding purging signal is triggered to control the compressed air to enter and suppress and eliminate the blockage of the measurement sampling pipeline.

[0047] (3) In the process of multiple fitting, the present invention adjusts the number of the second measuring element body according to the correction flow rate-switching interval parameter of each measuring sampling pipeline, which can solve the problem that when the flue gas velocity is large, the pressure disturbance has passed through the sampling port before the measuring sampling pipeline is switched. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the basic structure of the flue friction resistance calculation device according to this embodiment of the present invention;

[0049] Figure 2 This is a flowchart illustrating the method for calculating the friction resistance along the flue in this embodiment of the present invention.

[0050] Figure 3 This is a schematic diagram of the calculation device in this embodiment of the present invention, where the pressure sampling switching execution unit is a three-way valve;

[0051] Figure 4 A schematic diagram of the main body of the measuring device with the addition of a second measuring element in this embodiment of the present invention. Detailed Implementation

[0052] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0053] In the description of this invention, it should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0054] This embodiment presents a method for calculating the friction resistance along a flue, applicable to, for example... Figure 1 The illustrated flue gas friction resistance measurement device, based on the entire industrial flue gas duct, includes one or more pre-set combined switching pressure measurement devices. Each combined switching pressure measurement device comprises a first measuring element body 101, a second measuring element body 102, at least one set of pressure sampling switching execution units distributed along the pre-set flue gas duct sampling ports, and a controller 106. The first measuring element body 101 is used to measure the pressure at the beginning of the pre-set flue gas duct, and the second measuring element body 102 is used to measure the pressure in the measurement sampling pipeline where each pressure sampling switching execution unit is located. The controller 106 is used to implement the flue gas friction resistance measurement method, thereby achieving precise switching of the pre-set flue gas duct based on a standard flow rate. The series arrangement of the above-mentioned multiple sets of combined switching pressure measurement devices in the entire flue gas duct can achieve real-time precise location of dynamic identification of local resistance changes and fault conditions in the flue gas duct, effectively reducing steam loss and early detection and treatment of abnormal blockages and leaks. Meanwhile, the multidimensional data package of flue gas friction time-series measurement generated by the device is also a high-quality edge data that can be directly used for three-dimensional simulation of flue gas flow and for digital twin display.

[0055] Furthermore, the controller 106 can be a DCS, PLC, or integrated control unit. If a DCS or PLC is used, multiple sets of combined switching pressure measuring devices can share one controller 106. This embodiment takes the flue along the economizer 13-air preheater 15-dust collector 16-induced draft fan 17 as an example. Three sets of combined switching pressure measuring devices (namely, the first combined switching pressure measuring device 10, the second combined switching pressure measuring device 11, and the third combined switching pressure measuring device 12) are preset along the flue, located in the economizer 13-air preheater 15 section, the air preheater 15-dust collector 16 section, and the dust collector 16-induced draft fan 17 section, respectively. Figure 1 Taking the flue 14 (preset flue) of the economizer 13-air preheater 15 section as an example, the combined switching pressure measuring device 10 will be explained. Figure 1The combined switching pressure measuring device 10 includes a first measuring element body 101, a second measuring element body 102, three pressure sampling switching execution units distributed along the preset flue gas sampling ports (namely, the first pressure sampling switching execution unit 103, the second pressure sampling switching execution unit 104, and the third pressure sampling switching execution unit 105), and a controller 106. The first measuring element body 101 is used to measure the pressure at the beginning section of the preset flue gas (i.e., at the economizer 13), and the second measuring element body 102 is used to measure the pressure in the sampling pipeline where each pressure sampling switching execution unit is located. The first measuring element body 101 and the second measuring element body 102 can be pressure transmitters, and the first measuring element body 101 and the second measuring element body 102 respectively send the measured pressure to the controller 106. Each set of combined switching pressure measuring devices has multiple measuring sampling pipelines (such as L4, L5, and L6) distributed along the flue according to structural characteristics. Each measuring sampling pipeline is pre-set with a pressure sampling switching execution unit, which can be a pneumatic valve or an electric valve (hereinafter collectively referred to as a sampling valve). Figure 1 The two-way valve receives electrical signal commands from the controller 106 to control the opening and closing of the measurement sampling pipeline.

[0056] It should be noted that the three sets of combined switching pressure measuring devices installed between the economizer 13 and the air preheater 15 sections are merely an example. The specific number of sets of combined switching pressure measuring devices can be set according to the length of the flue. In addition, the number of sets of combined switching pressure measuring devices between the air preheater 15 and the dust collector 16 sections, and between the dust collector 16 and the induced draft fan 17 sections, can also be set according to the length of the flue. This embodiment does not impose any restrictions.

[0057] Furthermore, the pressure, temperature, and flow rate are obtained from the production control system. The controller 106 is also connected to the production control system 19 to receive the pressure, temperature, and flow rate output by the production control system 19. In addition, the pressure, temperature, and flow rate are also used by the three-dimensional simulation 18.

[0058] Specifically, such as Figure 2 As shown, the method for calculating the friction resistance along the flue gas duct executed on the controller includes:

[0059] S21, Initial Friction Resistance Timing Data Acquisition Steps: Receive pressure disturbances from the preset flue gas duct friction start section, and determine the initial flow rate based on the preset initial flow velocity of each measurement sampling pipeline. The pressure sampling switching execution unit switches segment by segment, and obtains the initial friction loss timing data packet based on the pressure disturbance, time delay, and pressure deviation of each measurement sampling pipeline. ;

[0060] S22, Initial True Velocity Distribution Calculation Steps: Calculate the initial friction resistance time-series data packet. Decomposition is performed to obtain the initial true velocity distribution along the friction resistance. ;

[0061] S23, Initial switching time interval calculation steps: Based on the initial true flow velocity distribution Calculate the initial switching time interval for each pressure sampling switching execution unit. ;

[0062] S24, Correction Factor - Standard Step Pressure Correlation Parameter Set Calculation Steps: Based on the initial switching time interval, control the preset flue to perform multiple pressure disturbances, compare the multiple data of step pressure values ​​of each measurement sampling pipeline, and obtain the true flow velocity distribution. By combining the pressure, temperature, flow rate, and correction factor of the flue gas / steam in the flue before pressure disturbance, a set of correction factor-standard step pressure correlation parameters for each measurement sampling pipeline under different operating conditions is obtained. ;

[0063] S25, Standard Flow Rate-Switching Interval Parameter Calculation Steps: Based on Correction Factor-Standard Step Pressure Correlation Parameter Set and the actual flow velocity distribution Perform fitting to obtain the corrected flow rate-switching interval parameter { After multiple fitting iterations, the corrected flow rate-switching interval parameters of each measurement sampling pipeline that meet the preset convergence conditions are obtained and used as the standard flow rate-switching interval parameters.

[0064] S26, Dynamic operating condition switching calculation and marking step: Based on the standard flow rate-switching interval parameters of each measurement sampling pipeline, a switching instruction strategy set for each measurement sampling pipeline is formed in the controller. When the controller detects the pressure disturbance at the beginning of the flue, it triggers different switching interval parameters according to its operating condition and outputs the switching instructions for each measurement sampling pipeline. The controller obtains the received measurement step pressure value, marks its time according to the corrected flow rate, and marks the time delay and pressure deviation of each measurement sampling pipeline.

[0065] S27, the step of generating multidimensional data packages for friction resistance time-series measurement, stores pressure disturbances, operating conditions, step pressure values ​​and marked times, time delays and pressure deviations of each measurement sampling pipeline into the database to form multidimensional data packages for flue friction resistance time-series measurement.

[0066] It should be noted that the symbols in the above steps (such as the preset initial flow rate in S21) are different. Initial friction loss timing data packet ) indicates that each represents a set of numbers, containing the values ​​sampled from the first measurement sampling line up to the Mth measurement sampling line (M represents the total number of measurement sampling lines).

[0067] In step S21, pressure disturbances from the preset flue gas flow path start section are received. The pressure sampling switching execution unit is switched segment by segment according to the preset initial flow velocity of each measurement sampling pipeline. Based on the pressure disturbances, time delays, and pressure deviations of each measurement sampling pipeline, an initial friction loss timing data packet is obtained, as follows:

[0068] Based on the total length of each measurement sampling pipeline along the preset flue gas path and the corresponding preset initial flow velocity The ratio is used to obtain the corresponding reference delay;

[0069] The pressure disturbance and its duration along the initial section of the preset flue gas duct are marked. Based on the reference time delay of the first measurement sampling pipeline, the pressure sampling switching execution unit of the first measurement sampling pipeline along the preset flue gas duct section is opened, and the pressure value of the first measurement sampling pipeline is continuously measured. The time of its first step pressure value is marked to obtain the initial actual time delay of the first measurement sampling pipeline. Based on the reference time delay of the second measurement sampling pipeline, the pressure sampling switching execution unit of the second measurement sampling pipeline along the preset flue gas duct section is opened, and the pressure value of the second measurement sampling pipeline is continuously measured. The time of its first step pressure value is marked to obtain the initial actual time delay of the second measurement sampling pipeline. The above method is repeated to obtain the initial actual time delay of each measurement sampling pipeline along the preset flue gas duct section. Based on the first step pressure value and the initial actual time delay of each measurement sampling pipeline, a set of initial friction resistance timing data packets is obtained. Each set of initial friction resistance timing data packets... Includes measurement timing data packets from the first measurement sampling line to the last measurement sampling line. These are the initial pressure, step time, pressure difference between the initial segment and the first to the Mth pressure channels, and the time interval between the initial segment and the pressure sampling switching execution unit between the first segment and the first to the Mth pressure channels. The time interval is the initial actual delay.

[0070] It should be noted that, This represents a single continuous time-series data packet. If the controller samples the data with a scan period of 100ms for 5 minutes under stress disturbance, there will be 3000 data packets.

[0071] In S22, the initial true velocity distribution along the friction resistance It is expressed as follows:

[0072] ;

[0073] in, Let m be the total length of the sampling pipeline for the m-th measurement. , Indicates the total number of measurement sampling pipelines; The initial actual time delay of the m-th channel; the total length of the m-th channel measurement sampling pipeline includes the distance between the sampling port of the m-th channel measurement sampling pipeline and the flue distance of the preset flue starting section, as well as the length of the m-th channel measurement sampling pipeline.

[0074] Based on the standard flow velocity obtained under the original flue design conditions, for example, when the boiler is currently operating at 100% rated load, the design flue gas velocity is 18 m / s, and the total length from the disturbance initiation section to the first measurement sampling pipeline is 18 m. Since the design flue gas velocity should be the disturbance transmitted by the first measurement sampling pipeline after 1 second, but the actual disturbance value is measured after 1.5 seconds, the initial true flow velocity from the initiation section to the first measurement sampling pipeline is 12 m / s.

[0075] In S23, the initial switching time interval , means as follows:

[0076] ;

[0077] in, This represents the time delay scaling factor for the m-th measurement sampling pipeline.

[0078] In step S24, by combining the pressure, temperature, flow rate, and correction factor of the flue gas / steam in the flue before pressure disturbance, a set of correction factor-standard step pressure correlation parameters for each measurement sampling pipeline under different operating conditions is obtained. The details are as follows:

[0079] ;

[0080] in, , representing the initial association parameters, , and These represent the flue gas pressure, temperature, and flow rate in the flue before the disturbance; , and They respectively represent based on , and Preset correction factor; This represents the set of correction factor-standard step pressure correlation parameters from the previous iteration; This indicates the corrected flow rate from the previous iteration; .

[0081] , and The process of obtaining the preset value of the correction factor is as follows: after multiple disturbances, the correction factors for different working conditions are obtained, and the parameters of similar working conditions are compared and adjusted. After multiple iterations, different switching time intervals and pressure step values ​​to be achieved are formed for each standard working condition, and all have converged to the allowable deviation range.

[0082] In S25, the correction factor-standard step pressure correlation parameter set is used. and the actual flow velocity distribution Perform fitting to obtain the corrected flow rate-switching interval parameter { Specifically, it includes:

[0083] Fitted Corrected Flow Rate ,as follows:

[0084] ;

[0085] in, This represents the actual flow velocity distribution in the previous iteration;

[0086] Based on the total length of each measurement sampling pipeline along the preset flue gas path and the corresponding calibration flow velocity The ratio is used to obtain the corresponding switching interval parameter. .

[0087] Furthermore, when the preset convergence condition is the same operating parameters, in a perturbation fitting process with more than a preset number of iterations, with a switching time interval deviation less than a preset time deviation threshold (e.g., 100ms), the measured step pressure value deviation is less than a preset pressure deviation threshold (e.g., 0.005kPa), and the corrected flow velocity and the actual flow velocity distribution satisfy the following:

[0088] ;

[0089] in, This represents the actual velocity distribution in this iteration; This indicates the corrected flow rate from the previous iteration; This indicates the minimum threshold for flow rate change; the same operating condition parameters refer to the fact that the pressure, temperature and flow rate deviations of the flue gas / steam in the flue before pressure disturbance are all less than the corresponding preset thresholds, such as the pressure, temperature and flow rate deviations being less than a certain minimum value, which is usually 0.5% of the full range of the corresponding parameters.

[0090] In this embodiment, the pressure disturbance can be triggered segment by segment of the flue, such as the pressure disturbance caused by steam soot blowing in the economizer and air preheater, or the pressure disturbance caused by sonic cleaning in the dust collector. The preset initial flow rate segment-by-segment switching strategy is as follows: When the economizer starts steam soot blowing, the controller marks the time and controls the economizer-air preheater segment first pressure sampling switching execution unit 103 to open, continuously measuring the pressure value of this path, marking the time of its first step pressure value, and obtaining the first iteration of the economizer-air preheater segment first measurement sampling pipeline flow time; when the economizer starts steam soot blowing again, the controller marks the time and controls the economizer-air preheater segment second pressure sampling switching execution unit 104 to open, continuously measuring the pressure value of this path, marking the time of its first step pressure value, and obtaining the first iteration of the economizer-air preheater segment. The second measurement sampling pipeline flow time is obtained sequentially using the method described above. Based on the total length of each measurement sampling pipeline in the economizer-air preheater section (this length is the sum of the flue spacing at each sampling point and the length of each measurement sampling pipeline in the economizer-air preheater section; for example, the total length of the first measurement sampling pipeline is equal to the sum of L1 and L4, the total length of the second measurement sampling pipeline is equal to the sum of L2 and L5, and the total length of the third measurement sampling pipeline is equal to the sum of L3 and L6), the controller calculates the initial velocity distribution of each measurement sampling pipeline in the economizer-air preheater section. Based on the initial velocity distribution, the controller obtains the initial switching time interval of the switching valves in each measurement sampling pipeline of the economizer-air preheater section. Using the aforementioned first fitting switching time interval, the economizer-air preheater section is subjected to multiple pressure disturbances. The controller compares multiple data points of the step pressure values ​​of each measurement sampling pipeline, and combines this with the pressure, temperature, flow rate, and correction factor of the flue gas and soot blowing steam in the economizer before the pressure disturbance, to obtain a set of correlation parameters between the correction factor and the standard step pressure for each measurement sampling pipeline under different operating conditions. The controller then uses this correlation parameter set as a global correction factor, and after multiple fitting iterations, obtains the standard flow rate-switching interval parameters for each measurement sampling pipeline that meet the preset convergence conditions.

[0091] In this embodiment, based on the final fitted converged standard flow rate-switching interval parameters for each measurement sampling pipeline, a switching command strategy set for each measurement sampling pipeline is formed in the controller. When the controller detects a pressure disturbance at the beginning of the flue gas path, it triggers different switching interval parameters according to the operating conditions and outputs switching commands for each measurement sampling pipeline. The controller receives the measured step pressure value, marks its time according to the corrected flow rate, and records the time delay and pressure deviation of each measurement sampling pipeline. The pressure disturbance, operating conditions, step pressure value, marked time, time delay, and pressure deviation of each measurement sampling pipeline are stored in the database to form a multi-dimensional data package for flue gas path resistance time-series measurement. These represent the step pressure value, the corresponding time, the time delay and pressure deviation of each measurement sampling pipeline, and the corresponding operating conditions (pressure, time, and flow rate), respectively. This is based on the above multidimensional data package for time-series measurement of flue gas friction resistance. This technology assists in the inversion and optimization analysis of fly ash deposition processes in the three-dimensional flow field of flues. It enables production control systems to dynamically identify changes in local resistance and accurately locate fault conditions in the flue in real time, providing early warning and control of abnormal blockages and leaks, and guiding adjustments to steam soot blowing strategies. It can also be sent to the enterprise data platform for three-dimensional simulation of flue gas flow and for digital twin and artificial intelligence applications after flue overhauls.

[0092] Furthermore, such as Figure 3 As shown, the pipeline switching valve can also be designed as a three-way valve. In addition to connecting the front-end flue sampling port and the rear-end measuring element body, it can also be connected to a compressed air purging pipe. The source of the compressed air pipe is an air compressor or a compressed air process system. Its on / off modes include sampling port closure, sampling port connected to the measuring element, and sampling port connected to compressed air. When a pressure disturbance is triggered and the measured flow rate deviations from the calibration flow rate are within the normal threshold range in both the front and rear measuring sampling pipelines, but the measurement deviation in this section exceeds the threshold (for example, the first and third measuring sampling pipelines are normal, and the second measuring sampling pipeline is abnormal), the pipeline switching valve purging signal can be triggered, and compressed air is introduced into the purging sampling port to distinguish between two faults: sampling pipe blockage and flue resistance change.

[0093] In addition, such as Figure 4 As shown, during multiple fitting processes, if, based on the corrected flow rate-switching interval parameters of each measurement sampling pipeline, a large flue gas velocity is detected, indicating that pressure disturbance has already passed through the sampling port of each measurement sampling pipeline before switching (for example, the length of the first measurement sampling pipeline is less than the distance between the first and second measurement sampling ports, and the flue gas velocity is greater than the ratio of the total length of the first measurement sampling pipeline to the time interval between the first and second measurement sampling ports), the number of the main body of the second measurement element is adjusted in this case. Figure 4 In this system, each measurement sampling pipeline is equipped with a measurement element body, namely the third measurement element body 107, the fourth measurement element body 108, and the fifth measurement element body 109.

[0094] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A method for calculating the friction resistance along a flue, characterized in that, Based on the entire industrial flue, one or more combined switching pressure measurement devices are preset; each set of combined switching pressure measurement devices includes a first measuring element body, a second measuring element body, at least one set of pressure sampling switching execution units distributed along the preset flue sampling port, and a controller, wherein the first measuring element body is used to measure the pressure of the initial section along the preset flue, and the second measuring element body is used to measure the pressure of the measurement sampling pipeline where each pressure sampling switching execution unit is located. The method for the controller to calculate the friction resistance along the flue includes: It receives pressure disturbances from the preset starting section of the flue gas duct and adjusts them according to the preset initial flow velocity of each measurement and sampling pipeline. The pressure sampling switching execution unit switches segment by segment, and obtains the initial friction loss timing data packet based on the pressure disturbance, time delay, and pressure deviation of each measurement sampling pipeline. ; Initial friction loss timing data packets Decomposition is performed to obtain the initial true velocity distribution along the friction resistance. ; Based on the initial true flow velocity distribution Calculate the initial switching time interval for each pressure sampling switching execution unit. ; Based on the initial switching time interval, the preset flue is controlled to undergo multiple pressure disturbances. By comparing multiple data points of the step pressure values ​​in each measurement and sampling pipeline, the true flow velocity distribution is obtained. By combining the pressure, temperature, flow rate, and correction factor of the flue gas / steam in the flue before pressure disturbance, a set of correction factor-standard step pressure correlation parameters for each measurement sampling pipeline under different operating conditions is obtained. ; Based on the correction factor-standard step pressure correlation parameter set and the actual flow velocity distribution Perform fitting to obtain the corrected flow rate-switching interval parameter { After multiple fitting iterations, the corrected flow rate-switching interval parameters of each measurement sampling pipeline that meet the preset convergence conditions are obtained and used as the standard flow rate-switching interval parameters. Based on the standard flow rate-switching interval parameters of each measurement sampling pipeline, a set of switching instruction strategies for each measurement sampling pipeline is formed in the controller. When the controller detects a pressure disturbance at the beginning of the flue, it triggers different switching interval parameters according to its operating conditions and outputs switching instructions for each measurement sampling pipeline. The controller obtains the received measurement step pressure value, marks its time according to the corrected flow rate, and marks the time delay and pressure deviation of each measurement sampling pipeline. Pressure disturbances, operating conditions, step pressure values ​​and marking times, time delays and pressure deviations of each measurement sampling pipeline are stored in the database to form a multidimensional data package for time-series measurement of flue resistance.

2. The method for calculating the friction resistance of a flue according to claim 1, characterized in that, The system receives pressure disturbances from the preset initial section of the flue gas duct. Based on the preset initial flow velocity of each measurement sampling pipeline, it switches the pressure sampling switching execution unit segment by segment. Based on the pressure disturbances, time delays, and pressure deviations of each measurement sampling pipeline, it obtains the initial friction loss timing data packet, as detailed below: Based on the total length of each measurement sampling pipeline along the preset flue gas path and the corresponding preset initial flow velocity The ratio is used to obtain the corresponding reference delay; The pressure disturbance and its duration along the preset flue gas duct's initial section are marked. Based on the reference time delay of each measurement sampling pipeline, the pressure sampling switching execution unit of each measurement sampling pipeline along the preset flue gas duct section is sequentially activated to continuously measure the pressure value of each measurement sampling pipeline. The time of the first step pressure value of each measurement sampling pipeline is marked to obtain the initial actual time delay of each measurement sampling pipeline. Based on the first step pressure value and the initial actual time delay of each measurement sampling pipeline, a set of initial friction resistance timing data packets is obtained. Each set of initial friction resistance timing data packets... Includes measurement timing data packets from the first measurement sampling line to the last measurement sampling line. These are the initial pressure, step time, pressure difference between the initial segment and the first to the Mth pressure channels, and the time interval between the initial segment and the pressure sampling switching execution unit between the first segment and the first to the Mth pressure channels. The time interval is the initial actual delay.

3. The method for calculating the friction resistance of a flue according to claim 1, characterized in that, Friction resistance Initial true velocity distribution It is expressed as follows: ； in, Let m be the total length of the measurement sampling pipeline. , Indicates the total number of measurement sampling pipelines; The initial actual time delay of the m-th channel; the total length of the m-th channel measurement sampling pipeline includes the distance between the sampling port of the m-th channel measurement sampling pipeline and the flue distance of the preset flue starting section, as well as the length of the m-th channel measurement sampling pipeline.

4. The method for calculating the friction resistance of a flue according to claim 3, characterized in that, Initial switching interval , means as follows: ； in, This represents the time delay scaling factor for the m-th measurement sampling pipeline.

5. The method for calculating the friction resistance of a flue according to claim 1, characterized in that, By combining the pressure, temperature, flow rate, and correction factor of the flue gas / steam in the flue before pressure disturbance, a set of correction factor-standard step pressure correlation parameters for each measurement sampling pipeline under different operating conditions is obtained. The details are as follows: ； in, , representing the initial association parameters, , and These represent the flue gas pressure, temperature, and flow rate within the flue before the disturbance, respectively. , and They respectively represent based on , and Preset correction factor; This represents the set of correction factor-standard step pressure correlation parameters from the previous iteration; This indicates the corrected flow rate from the previous iteration; .

6. The method for calculating the friction resistance of a flue according to claim 5, characterized in that, Based on the correction factor-standard step pressure correlation parameter set and the actual flow velocity distribution Perform fitting to obtain the corrected flow rate-switching interval parameter { Specifically, it includes: Fitted Corrected Flow Rate ,as follows: ； in, This represents the actual flow velocity distribution in the previous iteration; Based on the total length of each measurement sampling pipeline along the preset flue gas path and the corresponding calibration flow velocity The ratio is used to obtain the corresponding switching interval parameter. .

7. The method for calculating the friction resistance of a flue according to claim 1, characterized in that, When the preset convergence condition is the same operating parameters, during a perturbation fitting process with more than a preset number of iterations, and with a switching time interval deviation less than a preset time deviation threshold, the measured step pressure value deviation is less than a preset pressure deviation threshold, and the corrected flow velocity and the actual flow velocity distribution satisfy the following: ； in, This represents the actual velocity distribution in this iteration; The corrected flow rate of the previous iteration is indicated; the same operating condition parameters refer to the fact that the pressure, temperature and flow rate deviations of the flue gas / steam in the flue before the pressure disturbance are all less than the corresponding preset thresholds; This represents the minimum threshold for flow rate change.

8. The method for calculating the friction resistance of a flue according to claim 1, characterized in that, Also includes: During multiple fitting processes, the number of the main body of the second measuring element is adjusted according to the correction flow rate-switching interval parameter of each measurement sampling pipeline.

9. The method for calculating the friction resistance of a flue according to claim 1, characterized in that, Each pressure sampling switching execution unit is a two-way valve or a three-way valve; when it is a two-way valve, the first path is connected to the sampling port and the second path is connected to the main body of the second measuring element; when it is a three-way valve, the first path is connected to the sampling port, the second path is connected to the main body of the second measuring element, and the third path is connected to the compressed air purging pipe, so that when the resistance of the measurement sampling pipe is abnormally calculated, the corresponding purging signal is triggered to control the supply of compressed air.

10. A device for calculating the friction resistance along a flue, characterized in that, include: One or more combined switching pressure measuring devices; each combined switching pressure measuring device includes a first measuring element body, a second measuring element body, at least one set of pressure sampling switching execution units distributed along the preset flue sampling port, and a controller, wherein the first measuring element body is used to measure the pressure of the preset flue starting section, and the second measuring element body is used to measure the pressure of the measurement sampling pipeline where each pressure sampling switching execution unit is located; the controller is used to execute the calculation method as described in any one of claims 1 to 9.

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