Sensors, methods and systems for detecting sulfur dioxide concentration in flue gas

Abstract

This invention discloses a sensor, a method and system for detecting sulfur dioxide concentration in flue gas. The sensor includes a cathode, an anode, a zinc oxide nanofilm disposed on the anode, an insulating strip, a voltage-adjustable power supply, a voltage measurement module, and a current measurement module. The voltage-adjustable power supply applies voltage to the cathode and anode during gas concentration detection and adjusts the voltage between the cathode and anode until a Thomson discharge state is reached. The voltage measurement module detects the inter-electrode voltage between the cathode and anode. The current measurement module detects the discharge current. During concentration detection, a set of data corresponding to the concentration (temperature, humidity, pressure, discharge current, and inter-electrode voltage) is acquired. By changing the concentration, multiple sets of data are obtained. These data are then used to train an intelligent prediction model. Finally, the trained model is used to detect the gas concentration in real time. The system is simple in structure and highly sensitive.

Description

Technical Field

[0001] This invention belongs to the field of gas detection technology, and particularly relates to a sensor based on the Thomson discharge principle, and a method and system for detecting sulfur dioxide concentration in flue gas. Background Technology

[0002] With increasingly stringent environmental protection requirements, flue gas emitted by thermal power plants and smelters must meet environmental monitoring standards before it can be discharged. Sulfur dioxide content is often used as a primary monitoring indicator in environmental monitoring.

[0003] Currently, sulfur dioxide detection mainly employs infrared and ultraviolet-based detection methods or devices. For example, patent document CN213456661U, entitled "A Sulfur Dioxide Concentration Detection Device Based on Ultraviolet Light," addresses these issues by being expensive, requiring a large space (a separate analysis room), and being difficult to operate and maintain. Summary of the Invention

[0004] The purpose of this invention is to provide a sensor, a method and system for detecting sulfur dioxide concentration in flue gas, to solve the problems of high cost, large footprint and difficulty in operation and maintenance of existing devices.

[0005] The present invention solves the above-mentioned technical problems through the following technical solution: a sensor, comprising a cathode, an anode, a zinc oxide nanofilm disposed on the anode, an insulating strip, a voltage-adjustable power supply, a voltage measurement module, and a current measurement module; the cathode and anode are arranged in parallel opposite directions, the insulating strip is disposed on both sides of the cathode and anode, and the insulating strip, cathode, and anode enclose a cavity; the voltage-adjustable power supply is used to apply voltage to the cathode and anode during gas concentration detection and to adjust the voltage between the cathode and anode until the discharge between the cathode and anode reaches the Thomson discharge state; the voltage measurement module is used to detect the inter-electrode voltage between the cathode and anode; the current measurement module is used to detect the discharge current.

[0006] Furthermore, both the cathode and anode are made of copper sheets.

[0007] Furthermore, the distance between the zinc oxide nanofilm and the cathode is 1 mm.

[0008] The present invention also provides a method for detecting sulfur dioxide concentration in flue gas, comprising the following steps:

[0009] Step 1: Install a temperature and humidity sensor, a pressure sensor, and the sensor described above on the pipeline containing the gas, wherein the concentration of the gas is known.

[0010] Step 2: Power on and adjust the voltage between the sensor cathode and anode so that the discharge between the cathode and anode reaches the Thomson discharge state;

[0011] Step 3: Collect and obtain the gas temperature, humidity, and pressure values, as well as the discharge current and inter-electrode voltage, to obtain a set of data consisting of gas concentration, temperature, humidity, pressure value, discharge current, and inter-electrode voltage;

[0012] Step 4: Change the gas concentration, temperature, humidity, and pressure values, and repeat steps 2 and 3 to obtain multiple sets of data;

[0013] Step 5: Construct an intelligent prediction model. Use the temperature, humidity, pressure, discharge current, and inter-electrode voltage of the gas in the data as input samples and the corresponding gas concentration as output samples to train the intelligent prediction model and obtain a trained intelligent prediction model.

[0014] Step 6: Collect and acquire the temperature, humidity, pressure, discharge current, and inter-electrode voltage of the gas to be tested in real time, and input them into the trained intelligent prediction model to obtain the concentration of the gas to be tested.

[0015] Furthermore, between steps 4 and 5, there is also a step of adding data. The specific implementation process is as follows: multiple sets of data are interpolated using the interpolation method to obtain a large amount of data consisting of gas concentration, temperature and humidity, pressure value, discharge current and inter-electrode voltage.

[0016] Furthermore, the intelligent prediction model is a deep neural network model, a recurrent neural network model, a convolutional neural network model, or a backpropagation neural network model.

[0017] The present invention also provides a sulfur dioxide concentration detection system in flue gas, comprising:

[0018] Piping used for loading gas;

[0019] A temperature and humidity sensor installed on the pipeline for detecting gas temperature and humidity;

[0020] A pressure sensor installed on the pipeline for detecting gas pressure values;

[0021] A sensor installed on the pipeline as described above;

[0022] The control module is electrically connected to the temperature and humidity sensor, pressure sensor, and the sensor respectively. The control module is used to acquire multiple sets of data consisting of gas concentration, temperature and humidity, pressure value, discharge current, and inter-electrode voltage; to construct an intelligent prediction model, and to train the intelligent prediction model using the gas temperature and humidity, pressure value, discharge current, and inter-electrode voltage in the data as input samples and the corresponding gas concentration as output samples to obtain a trained intelligent prediction model; and to collect and acquire the temperature, humidity, pressure value, discharge current, and inter-electrode voltage of the gas to be measured in real time, and input them into the trained intelligent prediction model to obtain the concentration of the gas to be measured.

[0023] Beneficial effects

[0024] Compared with the prior art, the advantages of the present invention are as follows:

[0025] The present invention provides a sensor, a method and system for detecting sulfur dioxide concentration in flue gas, based on the Thomson discharge principle. It detects the discharge current and inter-electrode voltage under different gas concentrations, temperatures, humidity, and pressure values, obtaining multiple sets of data. These data are then used to train an intelligent prediction model, which is finally used to detect the gas concentration. This method and system eliminate the influence of temperature, humidity, and pressure on gas concentration detection, improves detection accuracy, and is low in cost, occupies little space, and is easy to operate and maintain. Attached Figure Description

[0026] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the sensor structure in an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the structure of the sulfur dioxide concentration detection system in flue gas in an embodiment of the present invention.

[0029] Among them, 1-cathode, 2-zinc oxide nanofilm, 3-anode, 4-insulating strip, 5-temperature and humidity sensor, 6-pressure sensor, and 7-sensor for detecting discharge current and inter-electrode voltage during Thomson discharge. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] The technical solutions of this application will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0032] like Figure 1 As shown, the sensor provided in this embodiment includes a cathode 1, an anode 3, a zinc oxide nanofilm 2 disposed on the anode 3, an insulating strip 4, a voltage-adjustable power supply, a voltage measurement module, and a current measurement module. The cathode 1 and anode 3 are arranged in parallel opposite directions, and the insulating strip 4 is disposed on both sides of the cathode 1 and anode 3, forming a cavity with the insulating strip 4, cathode 1, and anode 3. The voltage-adjustable power supply is electrically connected to the anode 3 and cathode 1 respectively, and is used to apply voltage to the cathode 1 and anode 3 during gas concentration detection, and to adjust the voltage between the cathode 1 and anode 3 until the discharge between the cathode 1 and anode 3 reaches the Thomson discharge state. The voltage measurement module is used to detect the inter-electrode voltage between the cathode 1 and anode 3 in the Thomson discharge state. The current measurement module is used to detect the discharge current in the Thomson discharge state.

[0033] In this embodiment, both the cathode 1 and the anode 3 are made of copper sheets, and the distance between the zinc oxide nanofilm 2 and the cathode 1 is 1 mm. This sensor has a simple structure, low cost, easy installation, and high sensitivity to gas detection.

[0034] The detection principle of the sensor in this embodiment is as follows: The anode and cathode of the sensor are placed inside the gas to be measured. An adjustable DC voltage is applied to the anode and cathode using an adjustable power supply. The current between the electrodes changes with the adjustable DC voltage. When the adjustable DC voltage applied between the electrodes is slowly increased, a very weak current can be measured by a current detection module (e.g., a sensitive galvanometer). As the adjustable DC voltage continues to increase, secondary ionization occurs in the gas between the electrodes, and the discharge current initially increases slowly, then suddenly increases exponentially rapidly, potentially increasing by 10%. 8 The discharge voltage increases by a factor of two, while the discharge voltage hardly increases. This abrupt transition is called gas breakdown, and the corresponding inter-electrode voltage is called the breakdown voltage V. SDuring gas breakdown, the increase in discharge current is independent of the external ionization source, and the discharge can be sustained by itself. In other words, the discharge has transitioned from a non-self-sustaining discharge to a self-sustaining discharge. This discharge region falls within the Thomson discharge range and is called Thomson discharge. Under different physical conditions, due to the different dominant fundamental physical processes, various forms of gas discharge phenomena will occur, exhibiting different gas discharge IV characteristics, i.e., the discharge current changes with the inter-electrode voltage. Record the inter-electrode voltage at this point and measure the gas discharge current output by the sensor.

[0035] This embodiment also provides a method for detecting sulfur dioxide concentration in flue gas, including the following steps:

[0036] Step 1: Install a temperature and humidity sensor, a pressure sensor, and the sensor described above on the pipeline containing the gas. The concentration of the gas is known.

[0037] like Figure 2 As shown, flue gas containing a known concentration of sulfur dioxide is contained in a closed pipeline. Temperature, humidity, pressure, discharge current, and inter-electrode voltage of the gas at different concentrations are obtained through temperature and humidity sensor 5, pressure sensor 6, and sensor 7 as described above, in order to acquire a large number of data samples.

[0038] Step 2: Power on and adjust the voltage between cathode 1 and anode 3 of sensor 7 so that the discharge between cathode 1 and anode 3 reaches the Thomson discharge state.

[0039] Based on the working principle of sensor 7, an adjustable DC voltage is applied to cathode 1 and anode 3, and the adjustable DC voltage is slowly increased until the discharge current increases exponentially, indicating that the discharge between cathode 1 and anode 3 is in the Thomson discharge state. The discharge current and inter-electrode voltage at this time are obtained, and the temperature, humidity and pressure values ​​of the gas at this time are also obtained. The temperature, humidity, pressure values, discharge current and inter-electrode voltage at this gas concentration are obtained, thus forming a set of data.

[0040] In the Tang Sheng discharge state, the discharge current is relatively large, which is easy to measure accurately and improves the accuracy of data samples, thereby improving the detection accuracy of gas concentration.

[0041] Step 3: Collect and obtain the temperature, humidity, and pressure values ​​of the gas, as well as the discharge current and inter-electrode voltage, to obtain a set of data consisting of gas concentration, temperature, humidity, pressure value, discharge current, and inter-electrode voltage.

[0042] Step 4: Change the gas concentration, temperature, humidity, and pressure values, and repeat steps 2 and 3 to obtain multiple sets of data.

[0043] To obtain a large amount of data, the concentration, temperature, humidity, and pressure of sulfur dioxide gas in the flue gas were changed. Steps 2 and 3 were repeated to obtain multiple sets of data consisting of gas concentration, temperature, humidity, pressure, discharge current, and inter-electrode voltage.

[0044] Step 5: Interpolate multiple sets of data using the interpolation method to obtain a large amount of data consisting of gas concentration, temperature and humidity, pressure, discharge current and inter-electrode voltage.

[0045] Training intelligent prediction models requires a large number of data samples; the larger the sample size, the higher the training accuracy. Simply relying on changing gas concentration, temperature, humidity, and pressure values ​​to obtain corresponding data (i.e., experimental data) is insufficient to achieve the required sample size for training. Therefore, this embodiment employs interpolation to interpolate these experimental data, obtaining a large amount of interpolated data. The experimental data and interpolated data together constitute the input samples required for training, thereby improving the training accuracy of the model and thus enhancing the detection accuracy of gas concentration.

[0046] Step 6: Construct an intelligent prediction model. Use the gas temperature, humidity, pressure, discharge current, and inter-electrode voltage in the data as input samples and the corresponding gas concentration as output samples to train the intelligent prediction model and obtain a trained intelligent prediction model.

[0047] Each set of data in the input sample consists of temperature, humidity, pressure, discharge current, and inter-electrode voltage at a certain gas concentration. The model is trained by using temperature, humidity, pressure, discharge current, and inter-electrode voltage as input quantities and the gas concentration corresponding to these temperature, humidity, pressure, discharge current, and inter-electrode voltage as output quantities, thus obtaining a trained model.

[0048] In this embodiment, the intelligent prediction model includes, but is not limited to, deep neural network models, recurrent neural network models, convolutional neural network models, or backpropagation neural network models. These models are all existing mature models that are easy to operate and implement.

[0049] Step 6: Collect and acquire the temperature, humidity, pressure, discharge current, and inter-electrode voltage of the gas to be tested in real time, and input them into the trained intelligent prediction model to obtain the concentration of the gas to be tested.

[0050] The concentration detection method described in this embodiment has the advantages of simple hardware requirements, low cost, easy installation, fast detection speed, and high sensitivity, and eliminates the influence of temperature, humidity, and pressure on gas concentration detection.

[0051] This embodiment also provides a sulfur dioxide concentration detection system in flue gas, including a pipeline, a temperature and humidity sensor 5, a pressure sensor 5, a sensor 7 for collecting discharge current and inter-electrode voltage, and a control module.

[0052] The pipeline is filled with flue gas. A temperature and humidity sensor 5 is installed on the pipeline to detect the gas temperature and humidity, a pressure sensor 6 is installed on the pipeline to detect the gas pressure, and a sensor 7 is installed on the pipeline to collect the discharge current and inter-electrode voltage when a Tonsic discharge occurs. The control module is electrically connected to the temperature and humidity sensor 5, the pressure sensor 6, and the sensor 7, respectively. During detection, flue gas with a known sulfur dioxide concentration is first loaded into the pipeline. An adjustable DC voltage is applied to the anode 3 and cathode 1 through the adjustable power supply of sensor 7, and the adjustable DC voltage is slowly increased until the discharge current increases exponentially. At this point, a Tonsic discharge state is reached. The voltage measurement module and the current measurement module are used to detect the inter-electrode voltage and the discharge current, respectively, to obtain the temperature, humidity, pressure, inter-electrode voltage, and discharge current corresponding to the gas concentration. The gas concentration, temperature, humidity, and pressure are changed, and the measurements are repeated to obtain multiple sets of experimental data. The experimental data are then interpolated to obtain interpolated data, and the experimental data and interpolated data constitute the training sample. An intelligent prediction model is built in the control module, and the model is trained using training samples to obtain a trained model. The trained model is then used to detect the concentration of sulfur dioxide gas in real time. This detection system has a simple hardware structure, low cost, easy installation, and simple operation and maintenance.

[0053] The above description only discloses specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or modifications that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for detecting the concentration of sulfur dioxide in flue gas, characterized by, Includes the following steps: Step 1: Install a temperature and humidity sensor, a pressure sensor, and a current sensor on the gas-filled pipeline. Each sensor includes a cathode, an anode, a zinc oxide nanofilm on the anode, an insulating strip, an adjustable power supply, a voltage measurement module, and a current measurement module. The cathode and anode are arranged parallel to each other, with the insulating strip on both sides of the cathode and anode, forming a cavity. The adjustable power supply applies voltage to the cathode and anode during gas concentration detection and adjusts the voltage between them until the discharge between them reaches the Thomson discharge state. The voltage measurement module is used to detect the inter-electrode voltage between the cathode and the anode; the current measurement module is used to detect the discharge current; the concentration of the gas is a known quantity. Step 2: Power on and adjust the voltage between the sensor cathode and anode so that the discharge between the cathode and anode reaches the Thomson discharge state; Step 3: Collect and obtain the gas temperature, humidity, and pressure values, as well as the discharge current and inter-electrode voltage, to obtain a set of data consisting of gas concentration, temperature, humidity, pressure value, discharge current, and inter-electrode voltage; Step 4: Change the gas concentration, temperature, humidity, and pressure values, and repeat steps 2 and 3 to obtain multiple sets of data; Step 5: Construct an intelligent prediction model. Use the temperature, humidity, pressure, discharge current, and inter-electrode voltage of the gas in the data as input samples and the corresponding gas concentration as output samples to train the intelligent prediction model and obtain a trained intelligent prediction model. Step 6: Collect and acquire the temperature, humidity, pressure, discharge current, and inter-electrode voltage of the gas to be tested in real time, and input them into the trained intelligent prediction model to obtain the concentration of the gas to be tested.

2. The method for detecting sulfur dioxide concentration in flue gas as described in claim 1, characterized in that, Between steps 4 and 5, there is also a step of adding data. The specific implementation process is as follows: multiple sets of data are interpolated using the interpolation method to obtain a large amount of data consisting of gas concentration, temperature and humidity, pressure value, discharge current and inter-electrode voltage.

3. The method for detecting sulfur dioxide concentration in flue gas as described in claim 1 or 2, characterized in that, The intelligent prediction model is a deep neural network model, a recurrent neural network model, a convolutional neural network model, or a backpropagation neural network model.

4. The method for detecting sulfur dioxide concentration in flue gas as described in claim 1, characterized in that: Both the cathode and anode are made of copper sheets.

5. The method for detecting sulfur dioxide concentration in flue gas as described in claim 1 or 4, characterized in that: The distance between the zinc oxide nanofilm and the cathode is 1 mm.

6. A system for detecting sulfur dioxide concentration in flue gas, characterized in that, include: Piping used for loading gas; A temperature and humidity sensor installed on the pipeline for detecting gas temperature and humidity; A pressure sensor installed on the pipeline for detecting gas pressure values; A sensor installed on the pipeline includes a cathode, an anode, a zinc oxide nanofilm on the anode, an insulating strip, a voltage-adjustable power supply, a voltage measurement module, and a current measurement module. The cathode and anode are arranged in parallel opposite directions, and the insulating strip is located on both sides of the cathode and anode, forming a cavity with the insulating strip, cathode, and anode. The voltage-adjustable power supply is used to apply voltage to the cathode and anode during gas concentration detection and to adjust the voltage between the cathode and anode until the discharge between the cathode and anode reaches the Thomson discharge state. The voltage measurement module is used to detect the inter-electrode voltage between the cathode and the anode; the current measurement module is used to detect the discharge current. The control module is electrically connected to the temperature and humidity sensor, the pressure sensor, and the sensor respectively. The control module is used to acquire multiple sets of data consisting of gas concentration, temperature and humidity, pressure value, discharge current, and inter-electrode voltage; to construct an intelligent prediction model, and to train the intelligent prediction model using the gas temperature and humidity, pressure value, discharge current, and inter-electrode voltage in the data as input samples and the corresponding gas concentration as output samples, to obtain a trained intelligent prediction model. It is also used to collect and obtain the temperature, humidity, pressure, discharge current, and inter-electrode voltage of the gas to be tested in real time, and input them into the trained intelligent prediction model to obtain the concentration of the gas to be tested.

7. The sulfur dioxide concentration detection system in flue gas as described in claim 6, characterized in that: Both the cathode and anode are made of copper sheets.

8. The sulfur dioxide concentration detection system in flue gas as described in claim 6 or 7, characterized in that: The distance between the zinc oxide nanofilm and the cathode is 1 mm.

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