Method and system for measuring pulverized coal concentration and wind speed in boiler wind powder pipeline

Abstract

The invention relates to the technical field of coal-fired power generation, in particular to a method and system for measuring pulverized coal concentration and wind speed in a boiler wind powder pipeline, and the method comprises the steps: separating introduced original wind powder airflow into concentrated-phase airflow and dilute-phase airflow through a coal-wind decoupling device; acquiring measurement parameters of the coal wind decoupling device, and inputting the measurement parameters into a pre-trained pulverized coal concentration and wind speed prediction model; and through the pulverized coal concentration and wind speed prediction model, inversion parameters representing the pulverized coal concentration and the wind speed in the wind powder pipeline are obtained through inversion, so that measurement is completed. According to the invention, the coal-wind decoupling device is used for separating the dense-phase airflow and the dilute-phase airflow, the pre-trained pulverized coal concentration and wind speed prediction model is combined, and key indexes are inversed by using the measurement parameters of the dilute-phase airflow, so that the risks of blockage and wear of the measurement device are remarkably reduced, and the reliability and accuracy of pulverized coal concentration and wind speed measurement are improved; and meanwhile, the adaptability to complex coal quality and high-flow-speed working conditions is enhanced.

Description

Technical Field

[0001] This invention relates to the field of coal-fired power generation technology, and in particular to a method and system for measuring pulverized coal concentration and wind speed in a boiler pulverized coal pipeline. Background Technology

[0002] Currently, online measurement of pulverized coal concentration and wind speed in boiler primary air ducts faces significant challenges. Existing technologies for online pulverized coal concentration measurement mainly include: indirect methods (including heat balance method, velocity-differential pressure method, etc.), direct methods, and non-contact measurement methods (such as optical methods, capacitance methods, electrostatic methods, and ultrasonic methods). Online wind speed measurement methods mainly include: pneumatic velocity measurement methods (typical devices such as Pitot tubes, flute tubes, airfoil tubes, etc.), thermoelectric velocity measurement methods (commonly used devices such as hot-wire anemometers, hot-wire anemometers), and correlation methods (such as optical methods, capacitance methods, electrostatic methods, and ultrasonic methods). However, due to the high pulverized coal concentration and fast flow rate in the primary air ducts, contact-type measuring devices generally suffer from problems such as clogging and wear, while optical-based measuring devices suffer from poor light path penetration. Meanwhile, measuring devices based on electrical and acoustic methods are limited by coal quality, are sensitive to moisture and ash content in the coal, and have low measurement accuracy. It is evident that due to the high concentration and high velocity of the primary air-coal gas flow, as well as the complex and variable coal quality, existing technologies are not sufficiently adaptable to complex coal qualities and cannot meet the real-time monitoring requirements under high concentration and high velocity conditions. This results in uneven air-coal distribution, affecting boiler combustion efficiency and safety.

[0003] Therefore, there is an urgent need to provide a technical solution to address the above problems. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method and system for measuring pulverized coal concentration and wind speed in a boiler pulverized coal pipeline.

[0005] In a first aspect, the present invention provides a method for measuring the pulverized coal concentration and air velocity in a boiler pulverized coal pipeline, the technical solution of which is as follows: The coal-air decoupling device separates the incoming raw air-coal gas flow into dense phase gas flow and dilute phase gas flow. The measurement parameters of the coal-air decoupling device are obtained and input into the pre-trained coal powder concentration and wind speed prediction model. By using a coal powder concentration and wind speed prediction model, inversion parameters characterizing the coal powder concentration and wind speed inside the coal powder pipeline are obtained to complete the measurement.

[0006] The beneficial effects of the method for measuring pulverized coal concentration and wind speed in a boiler pulverized coal pipeline of the present invention are as follows: The method of this invention separates the concentrated and dilute two-phase airflows using a coal-air decoupling device, combines a pre-trained coal powder concentration and wind speed prediction model, and uses the measurement parameters of the dilute phase airflow to invert key indicators. This significantly reduces the risk of blockage and wear of the measuring device, improves the reliability and accuracy of coal powder concentration and wind speed measurement, and enhances adaptability to complex coal quality and high flow rate conditions.

[0007] Based on the above scheme, the method for measuring pulverized coal concentration and wind speed in a boiler pulverized coal pipeline of the present invention can be further improved as follows.

[0008] In one alternative approach, it also includes: CFD numerical simulation was performed on the original air-coal flow in the coal-air decoupling device to generate a correlation database containing inlet state parameters and outlet state parameters. Support vector machines or neural network algorithms are used to train the associated database, establish the mapping relationship between measurement parameters and inversion parameters, and complete the construction of a prediction model for pulverized coal concentration and wind speed.

[0009] In the above-mentioned optional methods, a correlation database is generated through CFD numerical simulation, and the model is trained using support vector machine or neural network algorithms. This establishes an accurate mapping relationship between measurement parameters and inversion parameters, improves the accuracy and reliability of the coal powder concentration and wind speed prediction model, ensures the accuracy of measurement results, and enhances the model's adaptability to complex working conditions.

[0010] In one alternative approach, the measurement parameters include: The inlet pressure is measured by the inlet pressure sensor installed at the inlet of the coal-air decoupling device; The dense phase outlet pressure is measured by a first pressure sensor located at the dense phase outlet. The dilute phase outlet pressure is measured by a second pressure sensor located at the dilute phase outlet. The concentration of dilute phase coal powder measured by a coal powder concentration meter; The dilute phase outlet wind speed measured by the velocity measuring tube; The dilute phase outlet temperature and dilute phase moisture content are measured by temperature and humidity sensors.

[0011] Among the above-mentioned optional methods, by precisely defining the measurement parameters, a comprehensive and systematic data input foundation is provided for the prediction model, which improves the efficiency and reliability of data acquisition and optimizes the overall accuracy of the measurement process.

[0012] In one alternative approach, the inversion parameters include: the inlet coal powder concentration, inlet air velocity, dense phase outlet coal powder concentration, and dense phase outlet air velocity of the coal-air decoupling device.

[0013] Among the above-mentioned optional methods, by clearly defining the inversion parameters, the output target of the prediction model is clear and specific, which helps to accurately invert key indicators, optimize the control of boiler air-coal distribution uniformity, and improve combustion efficiency and safety.

[0014] In one alternative approach, the structure of the coal-air decoupling device is as follows: The structure can be categorized as follows: A top-light, bottom-dense structure, where the dilute phase gas exits from the top outlet and the dense phase gas exits from the bottom outlet; or a center-dense, periphery-light structure, where the dense phase gas exits from the center outlet and the dilute phase gas exits from the circumferential outlet; or a center-dense, periphery-dense structure, where the dilute phase gas exits from the center outlet and the dense phase gas exits from the circumferential outlet.

[0015] Among the above-mentioned optional methods, the three coal-air decoupling device structures are all based on the same separation principle, ensuring that the dense and dilute phase airflows are output independently to meet the parameter measurement requirements. Through the differentiated airflow separation design, they can flexibly adapt to different pipeline layouts and flow field characteristics, ensuring efficient separation and controllable emission of the dense and dilute phase airflows, significantly improving the device's adaptability to complex operating conditions, while optimizing separation efficiency and system stability, providing a reliable structural foundation for the accurate inversion of coal powder concentration and wind speed.

[0016] Secondly, the present invention provides a system for measuring pulverized coal concentration and wind speed in a boiler pulverized coal pipeline, the technical solution of which is as follows: The coal powder concentration and wind speed measurement system in the boiler air-coal duct includes: a coal-air decoupling device, a parameter measurement unit, and an inversion output unit; The coal-air decoupling device is used to separate the incoming raw coal-air flow into a dense phase flow and a dilute phase flow. The coal-air decoupling device is installed on the coal-air duct at the outlet of the coal mill. The parameter measurement unit is used to: acquire the measurement parameters of the coal-air decoupling device and input the measurement parameters into the pre-trained coal powder concentration and wind speed prediction model; The inversion output unit is used to: obtain inversion parameters characterizing the coal powder concentration and wind speed in the coal powder pipeline through the coal powder concentration and wind speed prediction model, so as to complete the measurement.

[0017] The beneficial effects of the coal powder concentration and wind speed measurement system in a boiler pulverized coal pipeline of the present invention are as follows: The system of this invention separates the concentrated and dilute two-phase airflows through a coal-air decoupling device, combines a pre-trained coal powder concentration and wind speed prediction model, and uses the measurement parameters of the dilute phase airflow to invert key indicators, which significantly reduces the risk of blockage and wear of the measuring device, improves the reliability and accuracy of coal powder concentration and wind speed measurement, and enhances the adaptability to complex coal quality and high flow rate conditions.

[0018] Based on the above solution, the coal powder concentration and wind speed measurement system in the boiler air-coal pipeline of the present invention can be further improved as follows.

[0019] In one alternative embodiment, it further includes: a data processing unit, the data processing unit being used for: CFD numerical simulation was performed on the original air-coal flow in the coal-air decoupling device to generate a correlation database containing inlet state parameters and outlet state parameters. Support vector machines or neural network algorithms are used to train the associated database, establish the mapping relationship between measurement parameters and inversion parameters, and complete the construction of a prediction model for pulverized coal concentration and wind speed.

[0020] In the above-mentioned optional methods, a correlation database is generated through CFD numerical simulation, and the model is trained using support vector machine or neural network algorithms. This establishes an accurate mapping relationship between measurement parameters and inversion parameters, improves the accuracy and reliability of the coal powder concentration and wind speed prediction model, ensures the accuracy of measurement results, and enhances the model's adaptability to complex working conditions.

[0021] In one alternative approach, the measurement parameters include: The inlet pressure is measured by the inlet pressure sensor installed at the inlet of the coal-air decoupling device; The dense phase outlet pressure is measured by a first pressure sensor located at the dense phase outlet. The dilute phase outlet pressure is measured by a second pressure sensor located at the dilute phase outlet. The concentration of dilute phase coal powder measured by a coal powder concentration meter; The dilute phase outlet wind speed measured by the velocity measuring tube; The dilute phase outlet temperature and dilute phase moisture content are measured by temperature and humidity sensors.

[0022] Among the above-mentioned optional methods, by precisely defining the measurement parameters, a comprehensive and systematic data input foundation is provided for the prediction model, which improves the efficiency and reliability of data acquisition and optimizes the overall accuracy of the measurement process.

[0023] In one alternative approach, the inversion parameters include: the inlet coal powder concentration, inlet air velocity, dense phase outlet coal powder concentration, and dense phase outlet air velocity of the coal-air decoupling device.

[0024] Among the above-mentioned optional methods, by clearly defining the inversion parameters, the output target of the prediction model is clear and specific, which helps to accurately invert key indicators, optimize the control of boiler air-coal distribution uniformity, and improve combustion efficiency and safety.

[0025] In one alternative approach, the structure of the coal-air decoupling device is as follows: The structure can be categorized as follows: A top-light, bottom-dense structure, where the dilute phase gas exits from the top outlet and the dense phase gas exits from the bottom outlet; or a center-dense, periphery-light structure, where the dense phase gas exits from the center outlet and the dilute phase gas exits from the circumferential outlet; or a center-dense, periphery-dense structure, where the dilute phase gas exits from the center outlet and the dense phase gas exits from the circumferential outlet.

[0026] Among the above-mentioned optional methods, the three coal-air decoupling device structures are all based on the same separation principle, ensuring that the dense and dilute phase airflows are output independently to meet the parameter measurement requirements. Through the differentiated airflow separation design, they can flexibly adapt to different pipeline layouts and flow field characteristics, ensuring efficient separation and controllable emission of the dense and dilute phase airflows, significantly improving the device's adaptability to complex operating conditions, while optimizing separation efficiency and system stability, providing a reliable structural foundation for the accurate inversion of coal powder concentration and wind speed.

[0027] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0028] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a flowchart illustrating a method for measuring pulverized coal concentration and air velocity in a boiler pulverized coal pipeline. Figure 2 This is a structural diagram of a coal-air decoupling device with a top-light and bottom-rich structure. Figure 3 A structural diagram of a coal-air decoupling device with a central concentrated and surrounding dilute structure; Figure 4 A structural diagram of a coal-air decoupling device with a centrally light and surroundingly dense structure; Figure 5 This is a system diagram of a coal powder concentration and air velocity measurement system in a boiler air duct. Reference numerals: 1. Coal mill; 2. Coal-air decoupling device; 3. Burner; 4. Recirculating fan; 5. Gas mixer; 11. Adjustable valve; 12. Check valve. Detailed Implementation

[0029] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0030] Figure 1 The diagram illustrates a flow chart of an embodiment of a method for measuring pulverized coal concentration and air velocity in a boiler pulverized coal duct provided by the present invention. Figure 1 As shown, it includes the following steps: S1. The raw air-coal decoupling device separates the incoming air-coal gas flow into a dense phase gas flow and a dilute phase gas flow. In S1: 1) The coal-air decoupling device is a special equipment that separates a high-concentration coal-air flow into two streams: a dense phase (rich in coal powder) and a dilute phase (sparse in coal powder) through a physical structure.

[0031] 2) The original air-coal flow is a gas-solid two-phase flow output from the coal mill. The original air-coal flow has a high coal powder concentration (about 0.3~0.9 kg / kg) and a fast flow rate (about 20~30 m / s).

[0032] 3) After the original air-coal gas flow is separated, the coal powder concentration in the dense phase gas flow is significantly higher than that in the original air-coal gas flow, while the coal powder concentration in the dilute phase gas flow is significantly reduced.

[0033] Specifically, the coal-air decoupling device achieves efficient gas-solid phase separation through gravity or centrifugal force. The dense phase gas flow is discharged from the dense phase outlet to the burner, while the dilute phase gas flow enters the recirculation system from the dilute phase outlet.

[0034] S2. Obtain the measurement parameters of the coal-air decoupling device and input the measurement parameters into the pre-trained coal powder concentration and wind speed prediction model. In S2: 1) Measurement parameters include inlet pressure, dense phase outlet pressure, dilute phase outlet pressure, dilute phase pulverized coal concentration, dilute phase outlet air velocity, dilute phase outlet temperature, and dilute phase moisture content.

[0035] 2) The coal powder concentration and wind speed prediction model is a mapping model built based on CFD numerical simulation and artificial intelligence algorithms (such as support vector machine and neural network). It outputs the target parameters by inputting multiple measured parameters.

[0036] Specifically, sensors collect data such as pressure, concentration, and wind speed of the dilute phase airflow in real time, which are used as input to the prediction model, providing a highly reliable data source for inversion.

[0037] S3. Using the coal powder concentration and wind speed prediction model, inversion parameters characterizing the coal powder concentration and wind speed inside the coal powder pipeline are obtained to complete the measurement. In S3: 1) The inversion parameters include the inlet coal powder concentration, inlet wind speed, dense phase outlet coal powder concentration, and dense phase outlet wind speed.

[0038] 2) Real-time inversion is a predictive model that calculates high-concentration parameters that cannot be directly measured based on input data through nonlinear mapping relationships.

[0039] Specifically: The predictive model uses stable measurements of dilute-phase low-concentration airflow to indirectly deduce the concentration and wind speed of the original wind-powder and dense-phase airflow, achieving high-precision online soft measurement.

[0040] It should be noted that, for ease of understanding, all the corresponding relationships involved are as follows: P0 is the inlet pressure; P1 is the dense phase outlet pressure; P2 is the dilute phase outlet pressure; c0 is the inlet coal powder concentration; c1 is the dense phase outlet coal powder concentration; c2 is the dilute phase coal powder concentration; v0 is the inlet air velocity; v1 is the dense phase outlet air velocity; v2 is the dilute phase outlet air velocity; T0 is the inlet temperature; T1 is the dense phase outlet temperature; T2 is the dilute phase outlet temperature; x0 is the inlet air humidity; x1 is the dense phase outlet air humidity; x2 is the dilute phase outlet air humidity; ρ0 is the inlet air density; ρ1 is the dense phase outlet air density; ρ2 is the dilute phase outlet air density; S0 is the inlet area; S1 is the dense phase outlet area; S2 is the dilute phase outlet area.

[0041] Where P0, P1, and P2 are in Pa; v0, v1, and v2 are in m / s; c0, c1, and c2 are in kg / kg; T0, T1, and T2 are in °C; x0, x1, and x2 are in kg / kg (dry air); and ρ0, ρ1, and ρ2 are in kg / m³. 3 The units for S0, S1, and S2 are meters. 2 .

[0042] In this embodiment, a coal-air decoupling device 2 is installed on the coal-air pipeline to concentrate and separate the coal-air flow. The original coal-air flow is converted into a dense phase flow and a dilute phase flow, which are discharged from the dense phase outlet and the dilute phase outlet of the coal-air decoupling device, respectively.

[0043] Seven online monitoring devices for status parameters are installed at the inlet and outlet of the coal-air decoupling unit. These devices are used to measure the inlet pressure P0, the dense phase outlet pressure P1, the dilute phase outlet pressure P2, the pulverized coal concentration c2, the wind speed v2, the temperature T2, and the moisture content x2, respectively.

[0044] Using the online monitoring devices for the inlet and outlet status parameters of the installed coal-air decoupling unit, online data of the measured parameters (P0, P1, P2, c2, v2, T2, x2) of the coal-air decoupling unit are acquired. The online data of these measured parameters are input into a coal powder concentration and wind speed prediction model to invert the coal powder concentration and wind speed at the inlet and outlet of the coal-air decoupling unit in real time. This includes the inlet coal powder concentration c0 and wind speed v0 of the coal-air decoupling unit, as well as the dense-phase outlet coal powder concentration c1 and wind speed v1, thus achieving online soft measurement of coal powder concentration and wind speed within the boiler's air-coal duct.

[0045] The technical solution of this embodiment separates the concentrated and dilute two-phase airflows through a coal-air decoupling device, combines a pre-trained coal powder concentration and wind speed prediction model, and uses the measurement parameters of the dilute phase airflow to invert key indicators, which significantly reduces the risk of blockage and wear of the measuring device, improves the reliability and accuracy of coal powder concentration and wind speed measurement, and enhances the adaptability to complex coal quality and high flow rate conditions.

[0046] In one alternative approach, it also includes: CFD numerical simulation was performed on the original air-coal flow in the coal-air decoupling device to generate a correlation database containing inlet state parameters and outlet state parameters. Support vector machines or neural network algorithms are used to train the associated database, establish the mapping relationship between measurement parameters and inversion parameters, and complete the construction of a prediction model for pulverized coal concentration and wind speed.

[0047] It should be noted that CFD numerical simulation refers to the three-dimensional simulation of gas-solid two-phase flow within a coal-air decoupling device based on computational fluid dynamics technology. By setting physical boundaries (such as inlet concentration, wind speed, and temperature range) and mesh generation, the fluid behavior under real-world operating conditions is simulated.

[0048] The associated database contains a mapping dataset of inlet state parameters (c0, v0, T0, x0) and outlet state parameters (P1, P2, c2, v2, etc.). The sample size n needs to cover typical operating conditions (preferably 100-500 sets) to ensure data comprehensiveness.

[0049] Support Vector Machine (SVM) / Neural Network (NN) algorithms are machine learning methods used to uncover the nonlinear relationships between measurement parameters (7 online measurement data points) and inversion parameters (4 inversion targets). SVM is suitable for small-sample, high-dimensional mappings, while neural networks (such as BP networks) excel at handling complex nonlinear couplings.

[0050] The mapping relationship refers to the mathematical function established through training that associates the measured parameters (P0, P1, P2, c2, v2, T2, x2) with the parameters to be solved (c0, v0, c1, v1), replacing the traditional analytical solution.

[0051] Specifically, numerical simulations of the gas-solid two-phase flow within the coal-air decoupling device are performed using CFD software (such as Fluent or OpenFOAM). Different inlet coal powder concentrations (e.g., c0 = 0.3~0.9 kg / kg), wind velocities (e.g., v0 = 20~30 m / s), temperatures (e.g., T0 = 60~120℃), and moisture content (e.g., x0 = 0.01~0.05 kg / kg) are set as boundary conditions to generate an association database containing n sets of input-output correspondences. Subsequently, a support vector machine or neural network algorithm is used to train this database to establish a predictive model from online measurement parameters to inversion parameters, overcoming the limitation of traditional methods in being unable to analyze nonlinear equation systems.

[0052] In this embodiment, CFD numerical simulations are performed on the gas-solid two-phase flow (original air-powder airflow) characteristics within the coal-air decoupling device to obtain simulation parameters of the gas-solid two-phase flow at the inlet and outlet of the coal-air decoupling device under typical operating conditions, and a correlation database of the inlet and outlet state parameters of the coal-air decoupling device is constructed. Support vector machine or neural network algorithms are used to train the correlation database of the inlet and outlet state parameters of the coal-air decoupling device to construct a prediction model for the coal powder concentration and wind speed of the coal-air decoupling device.

[0053] Furthermore, to explain the physical basis of the rich / dilute phase gas separation, based on the law of conservation of mass, the inlet and outlet state parameters of the coal-air decoupling device have the following relationship: (1) (2) Among them, S0, S1, and S2 are constant values ​​and are only related to the structure of the coal-air decoupling device.

[0054] Furthermore, to explain why the overall unit density (ρ≈constant) was calculated from the measured dilute phase temperature and humidity (T2, x2), the density of moist air is related to its pressure, temperature, and moisture content. The air densities at the inlet and outlet of the coal-air decoupling unit are as follows: (3) (4) (5) Where 1.293 is the density of dry air under standard conditions (0℃, 101325Pa) (unit: kg / m³). 3 ); 0.804 is the ratio of the density of water vapor to the density of dry air (ρ). 水蒸气 / ρ 干空气The value is derived from the ratio of the molecular weight of water vapor (18 g / mol) to the average molecular weight of dry air (28.97 g / mol), i.e., 18 / 28.97≈0.621. However, in actual engineering, temperature and pressure corrections need to be taken into account, so the value can be taken based on practical experience; 273 is the constant for converting the Celsius temperature scale to the absolute temperature scale (0℃=273K); 101325 is the standard atmospheric pressure (1 atm=101325 Pa).

[0055] Since the coal-air decoupling device basically does not involve heat and mass transfer, the temperature and moisture content inside the device remain unchanged, i.e., T0=T1=T2, x0=x1=x2. Furthermore, considering that the inlet and outlet pressures of the coal-air decoupling device range from approximately 500 to 3000 Pa, then... ≈ ≈ Therefore, the air density inside the coal-air decoupling device does not change much, i.e., ρ0≈ρ1≈ρ2. The air density inside the coal-air decoupling device is: (6) Where ρ is the air density inside the coal-air decoupling device, in kg / m³. 3 ; Furthermore, to explain the core principle of the nonlinear mapping relationship between the measured parameters and the inversion parameters, based on the friction and local resistance characteristics of the gas-solid two-phase flow, the inlet and outlet pressure drops of the coal-air decoupling device are related to its internal coal powder concentration, wind speed, and air density. Referring to formulas (5) and (6), the inlet and outlet pressure drops of the coal-air decoupling device are: (7) (8) in, This indicates the pressure difference between the inlet and the outlet of the dense phase; This represents the pressure difference between the inlet and the dilute phase outlet; the functions f() and g() are related to the structure of the coal-air decoupling device and are affected by the gas-solid two-phase flow parameters, and are typical nonlinear coupling functions. By simultaneously solving equations (1), (2), (7), and (8), a system of equations is constructed: (9) The known quantities are S0, S1, S2 (constant values) and P0, P1, P2, c2, v2, T2, x2 (online data), and the quantities to be solved are c0, v0, c1, v1. Therefore, the key to solving the system of equations (9) is the functions f() and g().

[0056] Furthermore, considering the nonlinear coupling problem of functions f() and g(), a prediction model between known quantities (P0, P1, P2, c2, v2, T2, x2) and unknown quantities (c0, v0, c1, v1) is constructed using support vector machine or neural network algorithms, and unknown quantities are calculated by inverting the known quantities.

[0057] Furthermore, during the CFD numerical simulation of the gas-solid two-phase flow characteristics within the coal-air decoupling device, the simulation boundary conditions were set to different inlet coal powder concentrations c0, inlet wind speeds v0, inlet temperatures T0, inlet air humidity x0, and different dilute phase outlet wind speeds v2. The inlet and outlet state parameters of the coal-air decoupling device under different boundary conditions were simulated and calculated, and a correlation database was constructed. (10) Where n is the number of samples in the associated database, preferably 100≤n≤500.

[0058] A coal powder concentration and wind speed prediction model for a coal-air decoupling device is constructed by training samples in the associated database (10) using support vector machine or neural network algorithms: (11) In one alternative approach, the measurement parameters include: The inlet pressure is measured by the inlet pressure sensor installed at the inlet of the coal-air decoupling device; The dense phase outlet pressure is measured by a first pressure sensor located at the dense phase outlet. The dilute phase outlet pressure is measured by a second pressure sensor located at the dilute phase outlet. The concentration of dilute phase coal powder measured by a coal powder concentration meter; The dilute phase outlet wind speed measured by the velocity measuring tube; The dilute phase outlet temperature and dilute phase moisture content are measured by temperature and humidity sensors.

[0059] In one alternative approach, the inversion parameters include: the inlet coal powder concentration (c0), the inlet air velocity (v0), the dense phase outlet coal powder concentration (c1), and the dense phase outlet air velocity (v1) of the coal-air decoupling unit.

[0060] In this embodiment, the inlet pressure P0 is the static pressure value of the air-coal flow at the inlet of the coal-air decoupling device, reflecting the flow energy state of the original airflow. The inlet pressure measuring device is a high-temperature resistant and wear-resistant pressure sensor (such as a piezoresistive type), which is installed in the straight pipe section at the inlet of the device (avoiding the vortex region).

[0061] The dense phase outlet pressure P1 is the static pressure value at the outlet of the dense phase gas flow (coal powder enrichment), characterizing the flow resistance characteristics of the high-concentration gas flow. The measuring device for the dense phase outlet pressure is also a high-temperature resistant and wear-resistant pressure sensor, installed at the center of the dense phase outlet pipeline.

[0062] The dilute phase outlet pressure P2 is the static pressure value at the outlet of the dilute phase gas flow (sparse coal powder), reflecting the flow characteristics of the low-concentration gas flow. The measuring device for the dilute phase outlet pressure is a standard pressure sensor, installed upstream of the dilute phase outlet pipe (≥5 times the pipe diameter from the outlet).

[0063] The dilute phase coal powder concentration c2 is the mass of coal powder carried per unit mass of gas in the dilute phase gas flow, controlled within the range of 0.05~0.2 kg / kg. The measuring device for the dilute phase coal powder concentration is a coal powder concentration meter based on the extinction method (such as a laser transmission type), which inverts the concentration by light intensity attenuation. A purging device can also be configured to prevent mirror contamination.

[0064] The dilute phase outlet velocity v2 is the axial velocity of the dilute phase airflow, typically 15~25 m / s. The device for measuring the dilute phase outlet velocity is a back-to-back velocity measuring tube (such as the BS-I type), which calculates the velocity through dynamic pressure difference. During installation, it is necessary to ensure that the direction of the flow is facing the airflow.

[0065] The dilute phase outlet temperature T2 and dilute phase moisture content x2 represent the temperature and water vapor mass ratio of the dilute phase gas flow. The measuring device for the dilute phase outlet temperature and dilute phase moisture content is an integrated temperature and humidity sensor (such as a capacitive hygrometer + PT100 temperature probe), which can be equipped with a dust filter.

[0066] Specifically, precise data acquisition is achieved through layered deployment: 1) Pressure parameters: Inlet pressure sensor, dense phase outlet pressure sensor, and dilute phase outlet pressure sensor capture P0, P1, and P2 in real time, respectively, providing core input for the pressure drop equation (Formula 7-8); 2) Dilute phase state parameters: Extinction method coal powder concentration meter obtains c2 online, back-mounted velocimeter dynamically measures v2, and temperature and humidity sensor synchronously monitors T2 and x2; 3) Collaborative control: All sensor signals are transmitted through shielded cables, and noise is eliminated through temperature compensation and filtering algorithms to generate a highly reliable online data stream.

[0067] In the extinction method for measuring the concentration of dilute phase coal powder, non-contact optical measurement (analyzing light intensity attenuation to invert concentration) can completely avoid direct contact between the sensor and the coal powder, significantly reducing the risk of mirror contamination and wear caused by high concentrations of coal powder. At the same time, the low concentration characteristics of the dilute phase gas flow (e.g., 0.05~0.2 kg / kg) ensure the effective penetration of the optical path, improve the accuracy of coal powder concentration measurement (error < ±3%), and are insensitive to changes in coal moisture and ash content, enhancing adaptability to complex coal sources.

[0068] In measuring dilute phase wind speed, the back-mounted velocimeter tube (BS-I type) directly calculates the flow velocity using the dynamic pressure difference principle. It has a simple structure, is wear-resistant, and can operate stably for a long time in low-concentration dilute phase airflow. Its directional flow-facing characteristics ensure high repeatability of wind speed measurement. At the same time, it can withstand high temperature and high dust environments, which is significantly better than contact equipment such as hot-wire anemometers that are easily affected by coal dust adhesion, thus ensuring the continuity and reliability of data acquisition.

[0069] By combining the two, highly reliable dilute phase parameters (c2, v2) can be provided for the prediction model, avoiding the technical bottleneck of direct measurement of the dense phase, improving the accuracy of the inversion results (c0, v0, c1, v1), and reducing the maintenance frequency of the system.

[0070] In one alternative approach, the structure of the coal-air decoupling device is as follows: The structure can be categorized as follows: A top-light, bottom-dense structure, where the dilute phase gas exits from the top outlet and the dense phase gas exits from the bottom outlet; or a center-dense, periphery-light structure, where the dense phase gas exits from the center outlet and the dilute phase gas exits from the circumferential outlet; or a center-dense, periphery-dense structure, where the dilute phase gas exits from the center outlet and the dense phase gas exits from the circumferential outlet.

[0071] Figure 2 , Figure 3 , Figure 4 Three different structures that can be selected for the coal-air decoupling device in this embodiment are shown respectively.

[0072] like Figure 2 The illustrated top-dense, bottom-dense structure separates coal particles using gravity. High-density coal powder settles downwards, forming a dense phase airflow, while a lighter airflow carrying a small amount of coal powder escapes upwards. Its structural feature is a diversion component (such as a concentrator) located at the top of the pipe's inner wall. The original air-coal airflow impacts the diversion component and is deflected downwards. The coal powder settles at the bottom of the pipe due to gravity and inertia, forming a dense phase airflow at the bottom and a dilute phase airflow at the top. This structure is suitable for vertical or steeply inclined air-coal ducts and has low spatial requirements.

[0073] like Figure 3 The central-concentrated, periphery-diluted structure shown utilizes a centrifugal force field (cyclone separator or guide vanes) to cause pulverized coal particles to concentrate towards the center, while the airflow diffuses circumferentially to form a dilute phase. Its structural features include flow dividers at both the top and bottom of the pipe, with the concentrated phase outlet (high-concentration pulverized coal gas flow directly to the burner) located at the center of the pipe, and dilute phase gas flow exiting through multiple evenly distributed annular outlets. This structure is suitable for horizontal pipe installations and high-velocity conditions (e.g., >25 m / s).

[0074] like Figure 4The illustrated center-dilute, periphery-concentrate structure separates the gas flow radially inward. Coal powder is thrown towards the pipe wall by inertia, while clean gas is drawn away from the center. Its structural features include a flow divider at the center of the pipe, and the dilute phase outlet (low-concentration gas extraction point) is also located at the center. A circumferential annular gap discharges the concentrated phase gas (designed close to the pipe wall). This structure is suitable for systems requiring precise control of the dilute phase concentration (such as recirculation ratio regulation) and offers strong anti-clogging properties.

[0075] Specifically, in the upper-dilute and lower-rich structure, after the original air-coal gas flow enters the device, the coal powder settles to the bottom collection area due to gravity, forming a dense phase gas flow that is directly supplied to the burner 3 from the lower outlet. The light gas flow is rectified by the top baffle and discharged from the upper outlet as a dilute phase gas flow, achieving efficient separation dominated by gravity.

[0076] In the central-rich and periphery-light structure, the original air-coal gas flow enters tangentially, causing the pulverized coal to accumulate towards the central axis under the action of centrifugal force. The dense phase gas flow is transported to the burner from the central outlet, and the clean gas flow after de-pulverization is evenly discharged from the circumferential annular outlet.

[0077] In the central light and surrounding dense structure, the airflow impacts the diversion component axially, and the pulverized coal falls into the circumferential collection area due to inertial impact on the pipe wall. The dense phase airflow is discharged from the circumferential gap outlet, and the low-concentration airflow in the central area is purified by an optional filter screen and then drawn from the central outlet to the recirculation fan 4, thereby improving the pulverized coal retention rate.

[0078] The present invention provides a coal powder concentration and wind speed measurement system in a boiler air-coal duct, comprising: a coal-air decoupling device, a parameter measurement unit, and an inversion output unit; The coal-air decoupling device is used to separate the incoming raw coal-air flow into a dense phase flow and a dilute phase flow. The coal-air decoupling device is installed on the coal-air duct at the outlet of the coal mill. The parameter measurement unit is used to: acquire the measurement parameters of the coal-air decoupling device and input the measurement parameters into the pre-trained coal powder concentration and wind speed prediction model; The inversion output unit is used to: obtain inversion parameters characterizing the coal powder concentration and wind speed in the coal powder pipeline through the coal powder concentration and wind speed prediction model, so as to complete the measurement.

[0079] The technical solution of this embodiment separates the concentrated and dilute two-phase airflows through a coal-air decoupling device, combines a pre-trained coal powder concentration and wind speed prediction model, and uses the measurement parameters of the dilute phase airflow to invert key indicators, which significantly reduces the risk of blockage and wear of the measuring device, improves the reliability and accuracy of coal powder concentration and wind speed measurement, and enhances the adaptability to complex coal quality and high flow rate conditions.

[0080] In one alternative embodiment, it further includes: a data processing unit, the data processing unit being used for: CFD numerical simulation was performed on the original air-coal flow in the coal-air decoupling device to generate a correlation database containing inlet state parameters and outlet state parameters. Support vector machines or neural network algorithms are used to train the associated database, establish the mapping relationship between measurement parameters and inversion parameters, and complete the construction of a prediction model for pulverized coal concentration and wind speed.

[0081] In one alternative approach, the measurement parameters include: The inlet pressure is measured by the inlet pressure sensor installed at the inlet of the coal-air decoupling device; The dense phase outlet pressure is measured by a first pressure sensor located at the dense phase outlet. The dilute phase outlet pressure is measured by a second pressure sensor located at the dilute phase outlet. The concentration of dilute phase coal powder measured by a coal powder concentration meter; The dilute phase outlet wind speed measured by the velocity measuring tube; The dilute phase outlet temperature and dilute phase moisture content are measured by temperature and humidity sensors.

[0082] In one alternative approach, the inversion parameters include: the inlet coal powder concentration, inlet air velocity, dense phase outlet coal powder concentration, and dense phase outlet air velocity of the coal-air decoupling device.

[0083] In one alternative approach, the structure of the coal-air decoupling device is as follows: The structure can be categorized as follows: A top-light, bottom-dense structure, where the dilute phase gas exits from the top outlet and the dense phase gas exits from the bottom outlet; or a center-dense, periphery-light structure, where the dense phase gas exits from the center outlet and the dilute phase gas exits from the circumferential outlet; or a center-dense, periphery-dense structure, where the dilute phase gas exits from the center outlet and the dense phase gas exits from the circumferential outlet.

[0084] It should be noted that, as Figure 5 As shown, the complete coal powder concentration and wind speed measurement system in the boiler air-coal pipeline includes a coal mill 1, a coal-air decoupling device 2, a burner 3, a recirculation fan 4, a mixer 5, an adjustable valve 11, and a check valve 12.

[0085] The inlet of the coal mill is connected to the coal-air decoupling device, which is used to grind raw coal into coal powder and mix it with hot air to form a high-concentration air-powder airflow.

[0086] The coal-air decoupling device separates the original coal-air flow into a dense phase flow and a dilute phase flow. The dense phase outlet of the coal-air decoupling device is connected to the burner, which receives the dense phase flow for coal-air combustion.

[0087] The dilute phase outlet of the coal-air decoupling unit is connected to the recirculation fan via an adjustable valve for regulating the flow rate of the dilute phase gas. The recirculation fan is connected to the mixer via a check valve for preventing hot air backflow from damaging the fan, and is used to draw dilute phase gas and deliver it to the mixer.

[0088] The mixer output is connected to the coal mill and is used to mix the dilute phase airflow with external hot air to form an airflow of suitable temperature or concentration that returns to the coal mill.

[0089] In this embodiment, the parameter measurement unit consists of seven types of industrial sensors: an inlet pressure sensor, a dense phase outlet wear-resistant pressure sensor, a dilute phase outlet pressure sensor, a laser transmission type pulverized coal concentration meter, a BS-I type back-mounted speed measuring tube, and an explosion-proof temperature and humidity transmitter.

[0090] The data processing unit adopts an embedded industrial controller. The data processing unit has a built-in CFD database storage module (such as pre-stored n=300 sets of working condition samples), a neural network algorithm operation module, and a real-time signal compensation program (to perform linear correction for temperature / pressure).

[0091] The inversion output unit includes an industrial touch screen for real-time display of the curves of c0, v0, c1, and v1, an output module for transmitting the v1 signal to the burner damper controller, and a communication interface for uploading data to an external terminal.

[0092] The overall workflow is as follows: The raw air-coal gas flow output from the coal mill is separated into dense phase and dilute phase gas flow by the coal-air decoupling device. The dilute phase gas flow passes sequentially through an adjustable valve, a recirculation fan, a check valve, and a mixer. The measured parameters collected by the parameter measurement unit are transmitted to the data processing unit via hardwired connections. The key parameters are inverted by the pre-trained prediction model, and the results are synchronously driven by the inversion output unit to drive the local display and remote control systems, thereby achieving closed-loop optimization of air-coal distribution.

[0093] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and represent a limitation on a specific order or sequence. Where appropriate, the order of use for similar objects can be interchanged so that the embodiments of this application described herein can be implemented in an order other than that shown or described.

[0094] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for measuring pulverized coal concentration and air velocity in a boiler pulverized coal duct, characterized in that, include: The coal-air decoupling device separates the incoming raw air-coal gas flow into dense phase gas flow and dilute phase gas flow. The measurement parameters of the coal-air decoupling device are obtained and input into the pre-trained coal powder concentration and wind speed prediction model. By using a coal powder concentration and wind speed prediction model, inversion parameters characterizing the coal powder concentration and wind speed inside the coal powder pipeline are obtained to complete the measurement.

2. The method for measuring pulverized coal concentration and wind speed in a boiler pulverized coal pipeline according to claim 1, characterized in that, Also includes: CFD numerical simulation was performed on the original air-coal flow in the coal-air decoupling device to generate a correlation database containing inlet state parameters and outlet state parameters. Support vector machines or neural network algorithms are used to train the associated database, establish the mapping relationship between measurement parameters and inversion parameters, and complete the construction of a prediction model for pulverized coal concentration and wind speed.

3. The method according to claim 2, characterized in that, The measurement parameters include: The inlet pressure is measured by the inlet pressure sensor installed at the inlet of the coal-air decoupling device; The dense phase outlet pressure is measured by a first pressure sensor located at the dense phase outlet. The dilute phase outlet pressure is measured by a second pressure sensor located at the dilute phase outlet. The concentration of dilute phase coal powder measured by a coal powder concentration meter; The dilute phase outlet wind speed measured by the velocity measuring tube; The dilute phase outlet temperature and dilute phase moisture content are measured by temperature and humidity sensors.

4. The method according to claim 3, characterized in that, The inversion parameters include: the inlet coal powder concentration, inlet air velocity, dense phase outlet coal powder concentration, and dense phase outlet air velocity of the coal-air decoupling device.

5. The method for measuring pulverized coal concentration and wind speed in a boiler pulverized coal pipeline according to claim 1, characterized in that, The structural type of the coal-air decoupling device is: The structure is characterized by a top-light and bottom-dense phase, where the dilute phase gas flows out from the top outlet and the dense phase gas flows out from the bottom outlet. or, The structure is characterized by a denser central phase and a lighter surrounding phase, with the dense phase gas exiting from the central outlet and the lighter phase gas exiting from the circumferential outlet. or, The structure is characterized by a light-phase flow at the center and a dense-phase flow around the perimeter, where the light-phase flow exits from the central outlet and the dense-phase flow exits from the circumferential outlet.

6. A system for measuring pulverized coal concentration and wind speed in a boiler pulverized coal duct, characterized in that, include: Coal-air decoupling device, parameter measurement unit, and inversion output unit; The coal-air decoupling device is used to separate the incoming raw coal-air flow into a dense phase flow and a dilute phase flow. The coal-air decoupling device is installed on the coal-air duct at the outlet of the coal mill. The parameter measurement unit is used to: acquire the measurement parameters of the coal-air decoupling device and input the measurement parameters into the pre-trained coal powder concentration and wind speed prediction model; The inversion output unit is used to: obtain inversion parameters characterizing the coal powder concentration and wind speed in the coal powder pipeline through the coal powder concentration and wind speed prediction model, so as to complete the measurement.

7. The coal powder concentration and wind speed measurement system in the boiler air-coal duct according to claim 6, characterized in that, Also includes: The data processing unit is used for: CFD numerical simulation was performed on the original air-coal flow in the coal-air decoupling device to generate a correlation database containing inlet state parameters and outlet state parameters. Support vector machines or neural network algorithms are used to train the associated database, establish the mapping relationship between measurement parameters and inversion parameters, and complete the construction of a prediction model for pulverized coal concentration and wind speed.

8. The coal powder concentration and wind speed measurement system in the boiler air-coal duct according to claim 7, characterized in that, The measurement parameters include: The inlet pressure is measured by the inlet pressure sensor installed at the inlet of the coal-air decoupling device; The dense phase outlet pressure is measured by a first pressure sensor located at the dense phase outlet. The dilute phase outlet pressure is measured by a second pressure sensor located at the dilute phase outlet. The concentration of dilute phase coal powder measured by a coal powder concentration meter; The dilute phase outlet wind speed measured by the velocity measuring tube; The dilute phase outlet temperature and dilute phase moisture content are measured by temperature and humidity sensors.

9. The coal powder concentration and wind speed measurement system in the boiler air-coal duct according to claim 8, characterized in that, The inversion parameters include: the inlet coal powder concentration, inlet air velocity, dense phase outlet coal powder concentration, and dense phase outlet air velocity of the coal-air decoupling device.

10. The coal powder concentration and wind speed measurement system in the boiler air-coal duct according to claim 6, characterized in that, The structural type of the coal-air decoupling device is: The structure is characterized by a top-light and bottom-dense phase, where the dilute phase gas flows out from the top outlet and the dense phase gas flows out from the bottom outlet. or, The structure is characterized by a denser central phase and a lighter surrounding phase, with the dense phase gas exiting from the central outlet and the lighter phase gas exiting from the circumferential outlet. or, The structure is characterized by a light-phase flow at the center and a dense-phase flow around the perimeter, where the light-phase flow exits from the central outlet and the dense-phase flow exits from the circumferential outlet.

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