Pulverized coal concentration detection system and method based on microwave method

Abstract

The invention relates to a pulverized coal concentration detection system and method based on a microwave method. The system comprises a microwave sensor, a microwave signal routing and conditioning module and a data processing and control module, the microwave sensor is of an annular structure, and a plurality of electrodes which are arranged in a total cross-section surrounding array mode are arranged in the annular structure. The microwave signal routing and conditioning module comprises a microwave switch matrix and a microwave signal conditioning unit; the microwave switch matrix is used for switching a signal transmission path between the electrodes, and the signal conditioning unit is used for generating a multi-band microwave signal and conditioning a received signal; and the data processing and control module is used for controlling the working parameters of the microwave signal routing and conditioning module and carrying out data processing. The device has the beneficial effects that the innovative switch matrix and multi-electrode design is adopted, and richer working condition information in the pulverized coal pipe can be obtained, so that the accuracy of pulverized coal concentration data is improved, and the detection effect is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of pulverized coal concentration detection, and more precisely, it relates to a pulverized coal concentration detection system and method based on the microwave method. Background Art

[0002] In coal-fired power plants, the combustion conditions of boilers are closely related to the pulverized coal transportation conditions of each burner. The speed and concentration of pulverized coal, as well as the air-powder uniformity of each pulverized coal burner, will directly affect the stability of the combustion conditions in the furnace and the combustion efficiency of the boiler. Once problems such as flame deflection and unstable ignition occur in the furnace, it will cause huge economic losses to the power plant equipment and greatly affect the safe operation of the unit. In order to precisely control the air flow and pulverized coal flow entering each burner to achieve the best combustion in the boiler, one of the key factors is the ability to measure the pulverized coal parameters entering the boiler in real time and accurately.

[0003] The flow of pulverized coal in the pulverized coal pipes of power plants belongs to a dilute-phase gas-solid two-phase flow. Due to the influence of factors such as the geometric shape of the flow channel, the temperature and humidity of the gas flow, and the physical properties of pulverized coal such as particle size, the flow patterns of pulverized coal flow are diverse and randomly distributed, making this process extremely complex. Therefore, the measurement of pulverized coal flow parameters is extremely challenging.

[0004] As a non-invasive sensing technology that has been widely used in various industrial fields, microwave technology has the advantages of non-invasiveness, no radioactivity, and full-section measurement. Introducing microwave technology into the scenario of pulverized coal detection can effectively overcome problems such as low measurement accuracy, easy wear, and high maintenance costs, thereby significantly improving the reliability, stability, and representativeness of measurement results and meeting the requirements of power plants for pulverized coal concentration detection.

[0005] In addition, in traditional microwave detection technologies, microwave signals of a single frequency are usually used for measurement. However, due to the different sensitivities and responses of microwave signals in different frequency bands to ambient noise, the characteristics such as the amplitude and phase of microwave signals may show differences at different frequencies, which in turn affects the detection effect. When measuring using only a single frequency, the interference of noise may lead to errors in the detection results. Summary of the Invention

[0006] The purpose of the present invention is to propose a pulverized coal concentration detection system and method based on the microwave method in view of the deficiencies of the prior art.

[0007] In the first aspect, a pulverized coal concentration detection system based on the microwave method is provided, including: a microwave sensor, a microwave signal routing and conditioning module, and a data processing and control module;

[0008] Among them, the microwave sensor is of a ring structure, and a plurality of electrodes arranged in a full-section surrounding array form are provided inside the ring structure; the microwave signal routing and conditioning module includes a microwave switch matrix and a microwave signal conditioning unit; the microwave switch matrix is used to switch the signal transmission path between the electrodes, and the signal conditioning unit is used to generate multi-band microwave signals and condition the received signals; the data processing and control module is used to control the working parameters of the microwave signal routing and conditioning module and perform data processing.

[0009] Preferably, the microwave signal conditioning unit includes a transmitting link and a receiving link; the transmitting link includes a voltage-controlled oscillator and a power amplifier; the receiving link includes a filter and a power detector; the voltage-controlled oscillator and the power detector are connected to the data processing and control module, and the power amplifier and the filter are connected to the microwave switch matrix.

[0010] Preferably, the data processing and control module includes a high-speed data acquisition and control unit and a host computer; the high-speed data acquisition and control unit is connected to the host computer; the high-speed data acquisition and control unit is used to control the parameters of the voltage-controlled oscillator and the microwave switch matrix and collect the real-time data of the power detector; the host computer is used for background data processing and analysis.

[0011] Preferably, the microwave switch matrix includes: a transmitting port SMA connector, a receiving port SMA connector, a routing SMA connector, and a switching circuit;

[0012] The switching circuit is used to realize the switching of the on / off state by controlling the supply voltage; the transmitting port SMA connector is connected to the transmitting link, and the receiving port SMA connector is connected to the receiving link; a plurality of routing SMA connectors are provided and are correspondingly connected to a plurality of electrodes in the microwave sensor.

[0013] In a second aspect, a method for detecting pulverized coal concentration based on the microwave method is provided, which is executed by the system according to any one of the first aspect, and includes:

[0014] Step 1, signal transmission: Under the control of the microwave signal routing and conditioning module and the data processing and control module, a signal transmission path is formed; according to the signal transmission path, a specified transmitting electrode of the microwave sensor emits a microwave signal into the internal space of the pulverized coal pipe;

[0015] Step 2, signal reception: A specified receiving electrode of the microwave sensor receives the microwave signal returned from the inside of the pulverized coal pipe; under the control of the microwave signal routing and conditioning module and the data processing and control module, a signal reception path is formed; the microwave signal is transmitted and processed according to the signal reception path.

[0016] Step 3, Signal Transmission Path Switching: For microwave signals of a specific frequency, switch the signal transmission path and the signal reception path to complete data acquisition at a single frequency point;

[0017] Step 4, Signal Frequency Scanning: Switch the frequency of the microwave signal to complete data acquisition at multiple frequency points;

[0018] Step 5, Data Processing and Analysis: Calculate based on the collected data to obtain the pulverized coal concentration data inside the pulverized coal pipe.

[0019] Preferably, before step 5, it further includes:

[0020] When there is no pulverized coal concentration inside the pulverized coal pipe, execute the signal emission, reception, path switching, and frequency scanning processes to collect calibration data.

[0021] Preferably, step 1 includes:

[0022] Step 1.1, Microwave Signal Excitation: The host computer controls the power supply port of the high-speed data acquisition and control unit to provide a specific voltage to the voltage-controlled oscillator. The voltage-controlled oscillator outputs a microwave signal with a specific frequency f1 and a specific power P1 according to the input voltage;

[0023] Step 1.2, Signal Power Amplification: After the microwave signal is processed by the power amplifier, the output power is increased;

[0024] Step 1.3, Signal Transmission Path Formation: The host computer controls the switch circuit in the microwave switch matrix to adjust the switch state of the transmission path to form a specific signal transmission path;

[0025] Step 1.4, Signal Transmission and Emission: The microwave signal is transmitted through the transmission path of the microwave switch matrix and the RF cable to the designated electrode of the microwave sensor, and the microwave signal is emitted into the internal space of the pulverized coal pipe through this electrode.

[0026] Preferably, step 2 includes:

[0027] Step 2.1, Signal Collection: The designated electrode in the signal sensor receives the microwave signal returned from the inside of the pulverized coal pipe;

[0028] Step 2.2, Signal Reception Path Formation: The host computer controls the switch circuit in the microwave switch matrix to adjust the switch state of the reception path to form a specific signal reception path;

[0029] Step 2.3, Signal Processing: The microwave signal received by the electrode is transmitted through the RF line and the signal reception path to the filter, and the filter eliminates noise and outputs a signal with a specific frequency;

[0030] Step 2.4, Signal Conversion: After being processed by the power detector, the microwave signal is converted into a digital signal and transmitted to the data processing and control module.

[0031] The beneficial effects of the present invention are as follows:

[0032] 1. The present invention develops a pulverized coal concentration detection system based on the microwave method. By the mapping relationship between the attenuation of the microwave signal and the volume fraction of the solid phase, the pulverized coal concentration of the measured cross-section is deduced. Moreover, the system provided by the present invention adopts an innovative switch matrix and multi-electrode design, which can obtain richer operating condition information inside the pulverized coal pipe, thereby improving the accuracy of the pulverized coal concentration data and significantly enhancing the detection effect.

[0033] 2. The present invention excites microwave signals of different frequencies and collects the signal response characteristics at multiple frequencies. This method can effectively reduce the interference of environmental noise on the measurement results and ensure more accurate and reliable detection results of the pulverized coal concentration.

[0034] 3. The present invention adopts a non-invasive microwave detection technology, effectively avoiding the problems of wear and high maintenance costs existing in the traditional methods, and further enhancing the stability and reliability of the system. Description of the Drawings

[0035] Figure 1 It is a schematic diagram of microwave detection of pulverized coal concentration;

[0036] Figure 2 It is a schematic diagram of the structure of the switch circuit;

[0037] Figure 3 It is a schematic diagram of the signal path of the electrode;

[0038] Figure 4 It is a schematic diagram of the structure of the pulverized coal concentration detection system based on the microwave method;

[0039] Figure 5 It is a schematic diagram of the structure of the microwave switch matrix;

[0040] Figure 6 It is a schematic diagram of the detection result of the pulverized coal concentration;

[0041] Description of the reference numerals: microwave sensor 1, voltage-controlled oscillator 2, power amplifier 3, microwave switch matrix 4, filter 5, power detector 6, high-speed data acquisition and control unit 7, host computer 8, transmitting port SMA connector 9, receiving port SMA connector 10, routing SMA connector 11. Detailed Embodiments

[0042] The present invention will be further described below in conjunction with embodiments. The description of the following embodiments is only for helping to understand the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0043] Embodiment 1:

[0044] Before introducing the technical solution of the present application, it is necessary to introduce the principle of detecting the pulverized coal concentration by the microwave method.

[0045] As Figure 1 shown, the powder feeding pipe for transporting the pulverized coal air flow can be regarded as a kind of waveguide system. During the transmission process of the microwave, it will be absorbed by the pulverized coal and cause signal attenuation, and the signal attenuation amount can be represented by the ratio of the output power of port B to the incident power of port A. Figure 1 Among them, I1 and V1 respectively represent the current and voltage of port A (input end); I2 and V2 respectively represent the current and voltage of port B (output end).

[0046] Assume that both the target to be measured and the wave field propagation are two-dimensional. In this case, the signal power formula is as follows:

[0047]

[0048] P(T) represents the transmitted signal power of port A, and P(z) represents the received signal power of port B. represents the attenuation constant, and z is the distance from the emission source to the receiving point.

[0049] The pneumatic conveying process of transporting pulverized coal belongs to a typical gas-solid two-phase flow. During the propagation process of the microwave signal in the gas-solid two-phase flow, there is a mapping relationship between the attenuation constant and the volume fraction of the solid phase.

[0050]

[0051] In the formula, K is the characteristic parameter of the sensor, which is determined by the size, structure and other characteristics of the sensor, V is the total volume of the detection field, and Vs is the volume occupied by the solid phase (i.e., pulverized coal).

[0052] Therefore, the attenuation constant of the signal can be inversely calculated by measuring the attenuation value of the microwave signal, and thus the volume fraction of the solid phase, that is, the solid phase concentration, of the measured cross-section can be calculated.

[0053] To solve the problems of the prior art, Embodiment 1 of the present application provides a pulverized coal concentration detection system based on the microwave method, including: a microwave sensor 1, a microwave signal routing and conditioning module, and a data processing and control module; each module closely cooperates to achieve high-precision detection of the pulverized coal concentration in the pulverized coal pipe of the coal mill.

[0054] Among them, the microwave sensor 1 has an annular structure and can directly replace a section of pulverized coal conveying pipeline in practical applications. It is the key detection unit of the system. The core unit of the sensor consists of 16 independent electrodes (numbered N1 - N16), which are mainly used to transmit and receive microwave signals and form a signal path inside the pulverized coal pipe. The 16 electrodes are arranged in a full - cross - section surrounding array form, which can achieve comprehensive signal detection, thus effectively avoiding the influence of the flow characteristics of pulverized coal on the measurement results and more truly reflecting the actual state inside the pipeline.

[0055] The electrodes are not directly inserted into the pipeline, significantly reducing the wear rate and maintenance frequency. The inner wall of the microwave sensor 1 is covered with a wear - resistant ceramic coating, which can withstand the long - term erosion of pulverized coal and meet the stringent requirements of power plant pulverized coal pipelines for wear resistance, high temperature resistance, and non - invasive detection.

[0056] The metal shell of the microwave sensor 1 plays a role of mechanical support, fixation, and protection. At the same time, it serves as the grounding layer of the microwave signal to prevent the interference of external electromagnetic fields.

[0057] In addition, the microwave signal routing and conditioning module includes a microwave switch matrix 4 and a microwave signal conditioning unit, which are responsible for the efficient transmission and conditioning of signals. The microwave switch matrix 4 is used to switch the signal transmission path between electrodes, and the signal conditioning unit is used to generate multi - band microwave signals and condition the received signals.

[0058] Specifically, the microwave switch matrix 4 includes: an external transmit port SMA connector 9, a receive port SMA connector 10, a routing SMA connector 11, and an internal switch circuit. The switch circuit can achieve the switching of the on / off state by controlling the supply voltage. The transmit port SMA connector 9 is connected to the transmit link, and the receive port SMA connector 10 is connected to the receive link; there are multiple routing SMA connectors 11, which are correspondingly connected to multiple electrodes in the microwave sensor 1. For example, 16 routing SMA connectors (numbered S1 - S16) arranged side by side in the middle are physically connected to the 16 metal electrodes N1 - N16 of the sensor through RF cables.

[0059] By controlling the switch circuit, a signal transmission path can be formed inside the switch matrix between the signal transmit port / receive port and the routing connectors S1 - S16, and a specific signal path will be formed inside the sensor accordingly. For example, when the transmit port is connected to S1 and the receive port is connected to S2, a signal path is formed inside the sensor that emits from electrode N1 and receives at N2. By switching the switch state, different signal paths between electrode pairs can be formed inside the sensor.

[0060] Such as Figure 2As shown, the a terminal of the switch circuit is connected to the routing SMA connector, the b terminal is connected to the transmitting port SMA connector, and the c terminal is connected to the receiving port SMA connector. There are a total of 16 groups of switch circuits.

[0061] In addition, the microwave signal conditioning unit includes a transmitting link and a receiving link; the transmitting link includes a voltage-controlled oscillator 2 and a power amplifier 3; the transmitting link controls the output frequency, power, etc. of the microwave signal through the voltage-controlled oscillator 2 and the power amplifier 3. The receiving link includes a filter 5 and a power detector 6, which are responsible for filtering noise signals and detecting signal strength, and converting the signal power (analog signal) into a voltage value (digital signal) for the upper computer to perform data processing and analysis.

[0062] In addition, the voltage-controlled oscillator 2 and the power detector 6 are connected to the data processing and control module, and the power amplifier 3 and the filter 5 are connected to the microwave switch matrix 4.

[0063] The data processing and control module includes a high-speed data acquisition and control unit 7 and an upper computer 8; the high-speed data acquisition and control unit 7 is connected to the upper computer 8.

[0064] Specifically, the upper computer 8 is responsible for background data processing and analysis and provides a user-friendly visualization interface. The high-speed data acquisition and control unit 7 is used to execute instructions from the upper computer 8, realize two-way communication with the hardware circuit, and control the working parameters of hardware circuits such as the voltage-controlled oscillator and the switch matrix. In addition, it is also responsible for collecting real-time data of the power detector and meeting the high-speed operation requirements of the system with a high sampling rate and data transmission rate.

[0065] Furthermore, the application scenario of this system is not limited to coal powder concentration measurement, and it is also applicable to the distribution detection of other gas-solid two-phase flows. For example, the distribution monitoring of particulate matters such as cement, flour, and sand can also be accurately detected through this system.

[0066] Embodiment 2:

[0067] Based on Embodiment 1, Embodiment 2 of the present application provides a method for detecting coal powder concentration based on the microwave method, including:

[0068] Step 1, signal transmission: Under the control of the microwave signal routing and conditioning module and the data processing and control module, a signal transmission path is formed; according to the signal transmission path, the designated transmitting electrode of the microwave sensor 1 transmits a microwave signal into the internal space of the coal powder pipe.

[0069] Step 1 includes:

[0070] Step 1.1, Microwave signal excitation: The host computer 8 controls the power supply port of the high-speed data acquisition and control unit 7 to supply a specific voltage to the voltage-controlled oscillator 2, and the voltage-controlled oscillator 2 outputs a microwave signal with a specific frequency f1 and a specific power P1 according to the input voltage;

[0071] Step 1.2, Signal power amplification: After the microwave signal is processed by the power amplifier 3, the output power is increased;

[0072] Step 1.3, Signal transmission path formation: The host computer 8 controls the switch circuit in the microwave switch matrix 4 to adjust the switch state of the transmission path to form a specific signal transmission path;

[0073] Step 1.4, Signal transmission and emission: The microwave signal is transmitted through the transmission path of the microwave switch matrix 4 and the RF cable to the designated electrode of the microwave sensor 1, and the microwave signal is emitted into the internal space of the pulverized coal pipe through this electrode.

[0074] Step 2, Signal reception: The designated receiving electrode of the microwave sensor 1 receives the microwave signal returned from the inside of the pulverized coal pipe; under the control of the microwave signal routing and conditioning module and the data processing and control module, a signal reception path is formed; the microwave signal is transmitted and processed according to the signal reception path.

[0075] Step 2 includes:

[0076] Step 2.1, Signal collection: The designated electrode in the microwave sensor 1 receives the microwave signal returned from the inside of the pulverized coal pipe;

[0077] Step 2.2, Signal reception path formation: The host computer 8 controls the switch circuit in the microwave switch matrix 4 to adjust the switch state of the reception path to form a specific signal reception path;

[0078] Step 2.3, Signal processing: The microwave signal received by the electrode is transmitted to the filter 5 through the RF line and the signal reception path, and the filter eliminates noise and outputs a signal with a specific frequency;

[0079] Step 2.4, Signal conversion: After the microwave signal is processed by the power detector 6, it is converted into a digital signal and transmitted to the data processing and control module.

[0080] After the above steps 1 and 2, the single-time microwave signal transmission and reception process is completed.

[0081] Step 3, Signal transmission path switching: For microwave signals with a specific frequency, switch the signal transmission path and the signal reception path to complete the data acquisition work at a single frequency point.

[0082] Step 4, Signal frequency sweeping: Switch the frequency of the microwave signal to complete the data acquisition work at multiple frequency points.

[0083] Step 5, Data Processing and Analysis: Calculate based on the collected data to obtain the pulverized coal concentration data inside the pulverized coal pipe.

[0084] It should be noted that the method provided in this embodiment is the method corresponding to the system provided in Embodiment 1. Therefore, for the parts that are the same or similar in this embodiment and Embodiment 1, reference can be made to each other and will not be elaborated in this application.

[0085] Embodiment 3:

[0086] Based on Embodiment 2, Embodiment 3 of this application provides a more specific method for detecting pulverized coal concentration based on the microwave method, including:

[0087] Step 1, Signal Transmission: Under the control of the microwave signal routing and conditioning module and the data processing and control module, form a signal transmission path; according to the signal transmission path, the designated transmission electrode of Microwave Sensor 1 emits microwave signals into the internal space of the pulverized coal pipe.

[0088] Step 2, Signal Reception: The designated receiving electrode of Microwave Sensor 1 receives the microwave signals returned from inside the pulverized coal pipe; under the control of the microwave signal routing and conditioning module and the data processing and control module, form a signal reception path; the microwave signals are transmitted and processed according to the signal reception path.

[0089] Step 3, Signal Transmission Path Switching: For microwave signals of a specific frequency, switch the signal transmission path and the signal reception path to complete the data acquisition work at a single frequency point.

[0090] Specifically, in Step 3, for microwave signals of a specific frequency, the system will perform 240 times of microwave signal transmission and reception. The difference between each time lies in the different signal transmission paths, mainly by controlling the on / off state of the switch circuits in the switch matrix to achieve the switching of the transmission paths.

[0091] Exemplarily, in Step 3, multi-path measurement is performed, including: each time different electrode pairs are selected as the transmission and reception electrodes to form a new signal path, and a total of sets of electrode pairs can be obtained. Considering the objective factor of hardware asymmetry and adding the situation of swapping transmission and reception, a total of sets of electrode pairs can be obtained, that is, 240 sets of signal transmission routes. As Figure 3 shown, it is a schematic diagram of the signal path when the N1 electrode is in the transmission state and the N2 - N16 electrodes are in the reception state, with a total of 15 paths. After 16 electrodes complete one round of switching, there are a total of 240 paths.

[0092] Furthermore, through 240 measurement data points, the measurement area is changed from a line to a surface, covering a larger measured area, and thus more accurate pulverized coal concentration data can be obtained.

[0093] It should be noted that the number of electrodes of the sensor and the number of ports of the switch matrix are not limited to 16. The number of electrodes can be increased or decreased according to specific requirements, thereby expanding or reducing the number of signal transmission paths. Correspondingly, the combination of signal transmission routes is not limited to 240 groups and can be flexibly configured. In addition, the selection range of signal transmission paths can be freely adjusted between 1 and 240, depending on the real-time data requirements of the application scenario. In scenarios with high requirements for real-time performance, fewer signal paths can be selected to improve the detection speed by reducing the amount of data, thereby accelerating the response time and enhancing real-time performance.

[0094] Through step 3, the data acquisition work at a single frequency point is completed.

[0095] Step 4: Signal frequency sweeping: Switch the frequency of the microwave signal to complete the data acquisition work at multiple frequency points.

[0096] In step 4, since microwave signals with different frequencies have different sensitivities and responses to ambient noise, the power response characteristics of the signals may vary at different frequencies, thereby affecting the detection effect. To obtain more comprehensive data, the system adjusts the input voltage of the voltage-controlled oscillator to co-excite microwave signals at 10 frequencies (numbered f1 - f10).

[0097] Furthermore, in this application, in step 4, the processes of signal transmission, reception, and path switching (i.e., steps 1 - 3) are repeated for each frequency point. Thus, 2400 groups of data are acquired at all frequency points, completing a complete data acquisition work.

[0098] It should be noted that the number of frequency sweep points of the microwave signal is not fixed at 10. Combining the real-time signal attenuation and noise conditions, the frequency band and the number of frequency points of the frequency sweep are dynamically adjusted to obtain more comprehensive signal response characteristics and improve the detection accuracy.

[0099] Step 5: When there is no pulverized coal concentration inside the pulverized coal pipe, execute the processes of signal transmission, reception, path switching, and frequency sweeping to collect calibration data.

[0100] In step 5, due to the different service conditions of each pulverized coal pipe on site, the electromagnetic field distribution formed by the signal inside is also different. In addition, there are also certain processing errors in each set of microwave sensing systems when they leave the factory. Therefore, before the pulverized coal concentration test is officially carried out, a calibration is required to eliminate the systematic error. The calibration process is to execute the signal transmission, reception, path switching, and frequency sweeping processes and collect calibration data when there is no pulverized coal concentration inside the pulverized coal pipe, that is, when the pulverized coal pipe does not transport pulverized coal. Among them, this application calculates the inherent signal attenuation P2 of the system using the data in the air state for error correction in subsequent tests. In addition, after calibration is completed, switch to the real-time detection mode of pulverized coal concentration, that is, when pulverized coal is transported inside the pulverized coal pipe, execute the signal transmission, reception, path switching, and frequency sweeping processes to obtain real-time test data.

[0101] Step 6, data processing and analysis: Calculate based on the collected data to obtain the pulverized coal concentration data inside the pulverized coal pipe.

[0102] Specifically, step 6 includes:

[0103] Step 6.1, signal power calculation: Calculate the received signal power P3 according to the working curve of the signal detector and the voltage value of the received signal.

[0104] Step 6.2, signal attenuation calculation: The difference between the transmitted and received signal powers is P3 - P1. Subtract the inherent signal attenuation P2 obtained by calibration to calculate the total signal attenuation P = P1 - P2 - P3. This value is the signal attenuation caused by the absorption of pulverized coal during the microwave transmission process.

[0105] Step 6.3, data averaging and calculation: Take the average value of 2400 sets of signal attenuation data, and combine the mapping relationship between the signal attenuation and the solid volume fraction to calculate the pulverized coal concentration.

[0106] Step 6.4, concentration output: The system finally outputs the pulverized coal concentration data inside the pulverized coal pipe to complete the detection.

[0107] It should be noted that the same or similar parts in this embodiment and Embodiment 2 can be referred to each other and will not be elaborated in this application.

Claims

1. A pulverized coal concentration detection system based on the microwave method, characterized in that, Comprising: A microwave sensor (1), a microwave signal routing and conditioning module, and a data processing and control module; Wherein, the microwave sensor (1) is of an annular structure, and a plurality of electrodes arranged in a full-section surrounding array form are provided inside the annular structure; the microwave signal routing and conditioning module includes a microwave switch matrix (4) and a microwave signal conditioning unit; the microwave switch matrix (4) is used to switch the signal transmission path between the electrodes, and the signal conditioning unit is used to generate multi-band microwave signals and condition the received signals; the data processing and control module is used to control the working parameters of the microwave signal routing and conditioning module and perform data processing.

2. The pulverized coal concentration detection system based on the microwave method according to claim 1, wherein The microwave signal conditioning unit includes a transmitting link and a receiving link; the transmitting link includes a voltage-controlled oscillator (2) and a power amplifier (3); the receiving link includes a filter (5) and a power detector (6); the voltage-controlled oscillator (2) and the power detector (6) are connected to the data processing and control module, and the power amplifier (3) and the filter (5) are connected to the microwave switch matrix (4).

3. The pulverized coal concentration detection system based on the microwave method according to claim 2, wherein The data processing and control module includes a high-speed data acquisition and control unit (7) and a host computer (8); the high-speed data acquisition and control unit (7) is connected to the host computer (8); the high-speed data acquisition and control unit (7) is used to control the parameters of the voltage-controlled oscillator (2) and the microwave switch matrix (4) and acquire the real-time data of the power detector (6); the host computer (8) is used for background data processing and analysis.

4. The pulverized coal concentration detection system based on the microwave method according to claim 3, characterized in that The microwave switch matrix (4) includes: a transmitting port SMA connector (9), a receiving port SMA connector (10), a routing SMA connector (11), and a switching circuit; The switching circuit is used to realize the switching of the on / off state by controlling the supply voltage; the transmitting port SMA connector (9) is connected to the transmitting link, the receiving port SMA connector (10) is connected to the receiving link; a plurality of routing SMA connectors (11) are provided and are correspondingly connected to the plurality of electrodes in the microwave sensor (1).

5. A method for detecting pulverized coal concentration based on the microwave method, characterized in that, Executed by the system according to any one of claims 1 to 4, including: Step 1, signal transmission: Under the control of the microwave signal routing and conditioning module and the data processing and control module, a signal transmission path is formed; according to the signal transmission path, a specified transmitting electrode of the microwave sensor (1) transmits a microwave signal into the internal space of the pulverized coal pipe; Step 2, signal reception: A specified receiving electrode of the microwave sensor (1) receives the microwave signal returned from the inside of the pulverized coal pipe; under the control of the microwave signal routing and conditioning module and the data processing and control module, a signal reception path is formed; the microwave signal is transmitted and processed according to the signal reception path; Step 3, signal transmission path switching: For microwave signals of a specific frequency, switch the signal transmission path and the signal reception path to complete the data acquisition work at a single frequency point; Step 4, signal frequency sweeping: Switch the frequency of the microwave signal to complete the data acquisition work at multiple frequency points; Step 5, data processing and analysis: Calculate according to the acquired data to obtain the pulverized coal concentration data in the pulverized coal pipe.

6. The pulverized coal concentration detection method based on the microwave method according to claim 5, wherein, Before step 5, it further includes: When there is no pulverized coal concentration inside the pulverized coal pipe, perform the signal emission, reception, path switching, and frequency sweeping processes to collect calibration data.

7. The pulverized coal concentration detection method based on the microwave method according to claim 5 or 6, characterized in that, Step 1 includes: Step 1.1, Microwave signal excitation: The host computer (8) controls the power supply port of the high-speed data acquisition and control unit (7) to provide a specific voltage to the voltage-controlled oscillator (2), and the voltage-controlled oscillator (2) outputs a microwave signal with a specific frequency f1 and a specific power P1 according to the input voltage. Step 1.2, Signal power amplification: The microwave signal is processed by the power amplifier (3) to increase the output power. Step 1.3, Signal emission path formation: The host computer (8) controls the switch circuit in the microwave switch matrix (4) to adjust the switch state of the emission path and form a specific signal emission path. Step 1.4, Signal transmission and emission: The microwave signal is transmitted through the emission path of the microwave switch matrix (4) and the RF cable to the designated electrode of the microwave sensor (1), and the microwave signal is emitted into the internal space of the pulverized coal pipe through this electrode.

8. The method for detecting pulverized coal concentration based on the microwave method according to claim 7, wherein, Step 2 includes: Step 2.1, Signal collection: The designated electrode in the microwave sensor (1) receives the microwave signal returned from inside the pulverized coal pipe. Step 2.2, Signal reception path formation: The host computer (8) controls the switch circuit in the microwave switch matrix (4) to adjust the switch state of the reception path and form a specific signal reception path. Step 2.3, Signal processing: The microwave signal received by the electrode is transmitted to the filter (5) through the RF line and the signal reception path, and the filter eliminates noise and outputs a signal with a specific frequency. Step 2.4, Signal conversion: The microwave signal is processed by the power detector (6), converted into a digital signal, and transmitted to the data processing and control module.

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