A method and system for detecting a gas component based on a hot-wire method

Abstract

The application relates to the technical field of gas detection, and provides a gas component detection method and system based on a hot-wire method. The method is characterized in that a hot-wire sensor is arranged in a coal sample tank of a coal sample gas injection displacement experiment device to realize real-time monitoring of the change of the methane concentration in the coal sample tank; and a gas adsorption model is constructed to determine the gas adsorption amount of the coal sample in the coal sample tank according to the real-time change of the methane concentration. Therefore, the change of the methane concentration in the coal sample tank is monitored in real time through the hot-wire sensor, the problem that the gas concentration cannot be detected in real time in the coal sample gas injection displacement experiment is solved by using the existing sampling detection method, the accuracy of real-time detection of the gas concentration is effectively improved, and the pressure disturbance and the interference with the gas displacement process caused by sampling are avoided; and the whole-process dynamic monitoring of the gas concentration, the adsorption amount and the adsorption rate in the gas displacement process can be realized, which provides important support for the research on the coal sample gas injection displacement technology.

Description

Technical Field

[0001] This application relates to the field of gas detection technology, and in particular to a gas component detection method and system based on the hot wire method. Background Technology

[0002] Injecting carbon dioxide into coal seams to displace methane is a crucial technique for improving coalbed methane recovery and achieving efficient coalbed methane extraction. Carbon dioxide has a stronger adsorption capacity than methane; under the same conditions, coal adsorbs significantly more carbon dioxide than methane. When high-pressure carbon dioxide is injected into the coal seam, it is preferentially adsorbed by the coal, occupying more adsorption sites and displacing the adsorbed methane. This frees the methane, making it easier to extract. Summary of the Invention

[0003] The purpose of this application is to provide a gas component detection method and system based on the hot wire method, so as to solve or alleviate the problems existing in the prior art.

[0004] To achieve the above objectives, this application provides the following technical solution:

[0005] This application provides a gas component detection method based on hot-wire method, comprising: installing a hot-wire sensor in the coal sample tank of a coal sample injection displacement experimental device to detect the methane concentration in the coal sample tank during the coal sample injection displacement experiment. Real-time monitoring of changes; using a constructed gas adsorption model, based on the methane concentration in the coal sample container. The real-time changes in the data are used to determine the amount of gas adsorbed in the coal sample within the coal sample container.

[0006] Preferably, based on the constructed hot wire concentration model, and according to the hot wire probe of the hot wire sensor under constant temperature conditions inside the coal sample container... Real-time power at any moment and / or real-time temperature To determine the contents of the coal sample container during the coal sample injection displacement experiment. methane concentration at time ;

[0007] The hot wire concentration model is as follows:

[0008]

[0009] In the formula, The thermal conductivity of methane and carbon dioxide in the coal sample container during the coal sample injection displacement experiment; This is the real-time temperature of the hot wire probe. The absolute temperature during the gas injection and displacement experiment of the coal sample. The radius of the hot wire probe.

[0010] The preferred gas adsorption model is:

[0011]

[0012] In the formula, During the gas injection displacement experiment of coal samples The amount of methane adsorbed by the coal sample at any given time; The reference tank volume for the coal sample gas injection displacement experimental device; The first preset pressure of methane injected into the reference tank of the coal sample gas injection displacement experimental device during the sample gas injection displacement experiment; The first gas equilibrium pressure in the coal sample container and the reference container during the coal sample gas displacement experiment; Standard temperature, Standard atmospheric pressure The absolute temperature during the gas injection and displacement experiment of the coal sample;

[0013] During the gas injection displacement experiment of coal samples The amount of carbon dioxide adsorbed by the coal sample at any given time; The second preset pressure for injecting carbon dioxide into the reference tank during the coal sample gas displacement experiment; The second gas equilibrium pressure in the coal sample container and the reference container during the coal sample gas displacement experiment;

[0014] The free space volume inside the coal sample container during the coal sample gas displacement experiment; During the gas displacement experiment of coal samples, the coal sample container The methane concentration at time 1; During the gas displacement experiment of coal samples, the coal sample container The pressure of constant time.

[0015] Preferably, according to the formula:

[0016]

[0017] Calculate the free space volume inside the coal sample container in the coal sample injection displacement experiment. ;

[0018] In the formula, The reference tank volume for the coal sample gas injection displacement experimental device; For reference, the gas pressure change inside the tank; This represents the change in gas pressure inside the coal sample container.

[0019] Preferably, the gas adsorption model also includes:

[0020]

[0021] In the formula, is the methane desorption rate in the time interval from time to time ; is the methane desorption rate in the time interval from time to time ; is the standard atmospheric pressure, is the absolute temperature during the coal sample gas injection displacement experiment; is the methane concentration in the coal sample tank during the coal sample gas injection displacement experiment at time ; is the pressure in the coal sample tank during the coal sample gas injection displacement experiment at time ; is the methane concentration in the coal sample tank during the coal sample gas injection displacement experiment at time ; is the pressure in the coal sample tank during the coal sample gas injection displacement experiment at time ;

[0022] is the carbon dioxide adsorption rate between time and time ;

[0023] Preferably, the coal sample gas injection displacement experiment device comprises a gas source, a reference tank, a coal sample tank, a vacuum pumping module, and a data acquisition module;

[0024] The gas source is connected to the reference tank and is used to inject gas into the reference tank;

[0025] The coal sample tank is provided with a pressure sensor and a hot-wire sensor and is in communication with the reference tank through a gas pipeline;

[0026] The vacuum pumping module is in communication with the reference tank and the coal sample tank pipeline, respectively, and can pump the reference tank and the coal sample tank to vacuum during the coal sample gas injection displacement experiment;

[0027] The data acquisition module is connected to the hot-wire sensor and the pressure sensor to obtain the real-time parameters of the hot-wire sensor and the real-time pressure in the coal sample tank during the coal sample gas injection displacement experiment; when the hot-wire sensor is constant-temperature type, the real-time power of the hot-wire sensor is obtained ; when the hot-wire sensor is constant-current type, the real-time temperature and the real-time power of the hot-wire sensor are obtained;

[0028] The coal sample tank and the reference tank are located in the same constant-temperature environment during the coal sample gas injection displacement experiment.

[0029] Preferably, in the coal sample gas displacement experiment, the coal sample container and the reference container are continuously evacuated. After injecting helium gas at a preset pressure into the reference container, the reference container and the coal sample container are connected. The free space volume inside the coal sample container is determined based on the gas pressure changes inside the reference container and the coal sample container. ;

[0030] In the coal sample gas injection displacement experiment, after evacuating the reference tank, a first preset pressure was injected. After adding methane, connect the coal sample container to the reference container, and wait until the first gas equilibrium pressure is reached. Then, disconnect the coal sample container from the reference container;

[0031] The reference tank was evacuated again, and the second preset pressure was injected. After removing carbon dioxide, reconnect the coal sample container to the reference container, and wait until the second gas equilibrium pressure is reached. Close the coal sample container to allow gas displacement within it;

[0032] In response to gas displacement within the coal sample container, the pressure within the coal sample container... Real-time monitoring is performed, and the real-time parameters of the hot wire sensor installed on the coal sample container are recorded.

[0033] The methane concentration in the coal sample container is calculated using a hot-wire concentration model based on real-time parameters from the hot-wire sensor; and the adsorption amounts of methane and carbon dioxide by the coal sample in the container are calculated using a gas adsorption model.

[0034] This application also provides a gas component detection system based on the hot-wire method, which detects gas during gas displacement using any of the above-described hot-wire method-based gas component detection methods. The system includes:

[0035] The concentration monitoring unit is configured to install a hot-wire sensor in the coal sample container of the coal sample injection displacement experimental device to monitor the methane concentration in the coal sample container during the coal sample displacement experiment. Real-time monitoring of changes;

[0036] The adsorption monitoring unit is configured to use a constructed gas adsorption model to detect methane concentration in the coal sample container. The real-time changes in the data are used to determine the amount of gas adsorbed in the coal sample within the coal sample container.

[0037] Beneficial effects:

[0038] In the gas component detection method based on the hot-wire method provided in this application embodiment, a hot-wire sensor is installed in the coal sample tank of the coal sample injection displacement experimental device to detect the methane concentration in the coal sample tank during the coal sample injection displacement experiment. The changes are monitored in real time; then, based on the constructed gas adsorption model, the methane concentration in the coal sample container is analyzed. determine the gas adsorption amount of the coal sample in the coal sample tank in real time. By means of the hot-wire sensor, the change of the methane concentration in the coal sample tank is monitored in real time overcome the problem that the gas concentration cannot be detected in real time in the coal sample injection displacement experiment in the prior art sampling detection method, effectively improve the accuracy of real-time detection of the gas concentration, avoid the pressure disturbance and interference on the gas displacement process caused by sampling, and realize the whole-process dynamic monitoring of the gas concentration, adsorption amount and adsorption rate in the gas displacement process, thereby providing important support for the research on the coal sample injection displacement technology. BRIEF DESCRIPTION OF DRAWINGS

[0039] The drawings accompanying the specification of this application serve to provide further understanding of the present application, the illustrative embodiments of the present application and the description thereof serve to explain the present application, and do not constitute an improper limitation on the present application. Among them:

[0040] Figure 1 a flowchart of a gas component detection method based on the hot-wire method according to some embodiments of the present application;

[0041] Figure 2 a structural schematic diagram of a coal sample injection displacement experiment device according to some embodiments of the present application;

[0042] Figure 3 a circuit schematic diagram of a hot-wire sensor according to some embodiments of the present application;

[0043] Figure 4 a structural schematic diagram of a gas component detection system based on the hot-wire method according to some embodiments of the present application. DETAILED DESCRIPTION

[0044] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments. Each example is provided by way of explanation of the present application rather than limiting the present application. In fact, those skilled in the art will clearly understand that modifications and variations can be made in the present application without departing from the scope or spirit of the present application. For example, features shown or described as part of one embodiment can be used in another embodiment to produce yet another embodiment. All other embodiments obtained by those skilled in the art based on the embodiments in the present application should belong to the scope of protection of the embodiments of the present application.

[0045] In the injection displacement experiment of the coal sample, the displacement process is a complex physical process accompanied by gas diffusion, adsorption-desorption equilibrium and component change. The experimental research on the injection of carbon dioxide to displace methane in the coal needs to monitor the change of the gas pressure and the change of the gas concentration, detect the process of the adsorption of carbon dioxide and the process of the displacement of methane.

[0046] In the experiment of injecting carbon dioxide to displace methane in coal, gas concentration and pressure are two key parameters. For the detection of gas concentration, the current common method is to take gas sample from the coal sample tank and detect it by gas chromatograph. However, the gas pressure in the coal sample tank will decrease in the sampling process, which will affect the accuracy of the displacement process. Moreover, this sampling and detection method cannot realize real-time detection.

[0047] Based on this, the embodiment provides a gas component detection method based on hot-wire method, which uses a hot-wire sensor to monitor the real-time change of methane concentration in the process of coal sample injection and displacement experiment, effectively solves the problem of difficult detection of gas concentration in the coal sample injection and displacement experiment, and does not need sampling, can realize real-time monitoring of the change of gas concentration in the tank, and provides important support for the research of coal injection and displacement technology.

[0048] First of all, it should be pointed out that the temperature in the embodiment is Kelvin. As shown in the figure, the gas component detection method based on hot-wire method includes: Figures 1 to 3

[0049] Step S101, a hot-wire sensor is arranged in the coal sample tank of the coal sample injection and displacement experiment device to monitor the real-time change of methane concentration in the coal sample tank in the process of coal sample injection and displacement experiment.

[0050] In the embodiment, the coal sample tank is a cylindrical high-pressure sealed container for placing coal samples and injecting gas, and the gas displacement process is carried out in the coal sample tank. A mounting threaded hole is arranged in the center of the top cover of the coal sample tank in the axial direction, which is used to mount the hot-wire sensor. The hot-wire sensor includes a control circuit and a hot-wire probe. The control circuit can control the temperature of the hot-wire sensor, and the hot-wire probe extends into the inside of the coal sample tank. Specifically, the hot-wire sensor is packaged in a metal tube, and the metal tube is screwed into the mounting threaded hole.

[0051] Here, the hot-wire sensor can be a constant-temperature (constant temperature) hot-wire sensor or a constant-current (constant current) hot-wire sensor. For the constant-temperature hot-wire sensor, the hot-wire temperature does not change during the gas displacement experiment, and the hot-wire power changes with the change of gas concentration and pressure in the coal sample tank; for the constant-current hot-wire sensor, the current flowing through the hot-wire does not change during the gas displacement experiment, and the hot-wire temperature changes with the change of gas concentration and pressure in the coal sample tank.

[0052] In the embodiment, the hot-wire sensor is composed of a hot-wire probe composed of a thermistor and a control circuit. For the constant-temperature hot-wire sensor, the control circuit is composed of a Wheatstone bridge, an operational amplifier and a power supply. Four resistors form a Wheatstone bridge, in which and are fixed resistors, is a variable resistor, ​​It is a thermistor. It is an operational amplifier. It serves as an adjustable reference voltage source. The constant-temperature hot-wire sensor detects the imbalance signal output by the Wheatstone bridge, amplifies it, and drives the power supply to adjust the voltage so that the Wheatstone bridge is rebalanced, thereby maintaining a constant temperature during the operation of the hot-wire sensor.

[0053] In other words, to make the thermistor The temperature is kept constant, that is, the thermistor is kept at a constant temperature. To maintain a constant output voltage, the Wheatstone bridge's output voltage must be kept zero. Operational amplifier. With power supply Forming feedback control, when the thermistor A decrease in temperature causes a decrease in resistance, leading to an imbalance in the Wheatstone bridge, which in turn affects the operational amplifier. Increasing the output voltage thereby improving the thermistor Power causes its temperature to rise, and vice versa; furthermore, based on voltage and thermistor... The resistance value determines the real-time power of the thermistor. .

[0054] For constant current type hot wire sensors, a constant current power supply is used to power the hot wire, and its voltage is measured. The thermistor resistance is then calculated based on the voltage. The resistance value is used to further calculate its real-time temperature. and real-time power Regardless of whether a constant-temperature or constant-current hot-wire sensor is used, the relationship between the parameters of the hot-wire sensor and the gas concentration in the coal sample container (i.e., the hot-wire concentration model) is based on the real-time parameters (real-time power) of the hot-wire probe of the hot-wire sensor under constant-temperature conditions. and / or real-time temperature ), calculate the contents of the coal sample container during the coal sample injection displacement experiment. methane concentration at time The hot-line concentration model constructed is as follows:

[0055]

[0056] In the formula, The thermal conductivity of methane and carbon dioxide in the coal sample container during the coal sample injection displacement experiment; This is the real-time temperature of the hot wire probe. The absolute temperature during the coal sample gas injection displacement experiment (the coal sample gas injection displacement experiment is carried out under isothermal conditions, and the real-time temperature inside the coal sample container remains constant during the displacement process). The radius of the hot wire probe.

[0057] That is, when a constant-temperature hot-wire sensor is used, the concentration change of the methane in the coal sample tank is reflected by the real-time change of the power of the hot-wire sensor on the coal sample tank, and the thermal conductivity of the gas (carbon dioxide, methane) in the coal sample tank at the experimental temperature and pressure.

[0058] In the coal sample gas injection displacement device, the gas source is connected with the reference tank for injecting gas into the reference tank; the coal sample tank is provided with a pressure sensor (first pressure sensor) and a hot-wire sensor, and is in communication with the reference tank through a gas pipeline; the vacuum module (vacuum pump) is in communication with the reference tank and the coal sample tank pipeline, and is specifically connected to the gas pipeline between the coal sample tank and the reference tank through a three-way valve, so that the reference tank and the coal sample tank can be vacuumized during the coal sample gas injection displacement experiment. At the same time, the reference tank is also provided with a pressure sensor (second pressure sensor) for monitoring the gas pressure in the reference tank.

[0059] The hot-wire sensor, the pressure sensor on the coal sample tank, and the pressure sensor on the reference tank are connected with the data acquisition module, so that the real-time parameters of the hot-wire sensor (when the hot-wire sensor is constant-temperature, the real-time power of the hot-wire sensor is acquired ; when the hot-wire sensor is constant-current, the real-time temperature and real-time power of the hot-wire sensor are acquired) and the real-time pressures in the coal sample tank and the reference tank can be acquired in real time through the data acquisition module.

[0060] In the embodiment, a thermostat is further provided outside the coal sample tank and the reference tank for keeping the temperature constant during the experiment, so as to maintain the constant temperature of the coal sample gas injection displacement experiment; at the same time, the gas source includes a methane gas cylinder, a carbon dioxide gas cylinder and a helium gas cylinder, and different types of gas source cylinders are connected with the reference tank, so as to inject different types of gas into the reference tank at different stages of the experiment.

[0061] Before conducting the coal sample gas injection displacement experiment, a certain mass of coal sample was weighed and placed in the coal sample container. The airtightness of the experimental apparatus was then tested. After passing the airtightness test, the equipment was kept at a constant temperature in a constant-temperature chamber. Then, after continuously evacuating the reference container and the coal sample container for 6 hours using a vacuum pump, a helium cylinder was connected to the reference container. The helium cylinder was opened, and helium was injected into the reference container. Once the gas pressure in the reference container reached the set pressure, the helium cylinder was closed, and the coal sample container and the reference container were connected, allowing helium to flow from the reference container into the coal sample container. After the gas pressures in the coal sample container and the reference container reached equilibrium, the gas pressure change in the coal sample container was acquired using a first pressure sensor. The gas pressure change inside the reference tank is obtained through a second pressure sensor. And according to the formula:

[0062]

[0063] Calculate the free space volume inside the coal sample container in the coal sample injection displacement experiment. In the formula, The reference tank volume for the coal sample gas injection displacement experimental device; For reference, the gas pressure change inside the tank; This represents the change in gas pressure inside the coal sample container.

[0064] In the coal sample gas displacement experiment, the valve of the coal sample tank is opened and the valve of the reference tank is closed. The coal sample tank is continuously evacuated using a vacuum pump to degas the coal sample. After the evacuation is completed, the valve of the coal sample tank is closed and the valve of the reference tank is opened to connect the vacuum pump to the reference tank. The vacuum pump is then used to evacuate the reference tank. After the reference tank is evacuated, the valves of the vacuum pump and the reference tank are closed.

[0065] Connect the methane cylinder to the reference tank's injection port and inject methane into the reference tank. When the methane pressure in the reference tank reaches the first preset pressure... Then, close the methane cylinder, connect the coal sample container and the reference container, allowing the methane gas in the reference container to flow freely into the coal sample container until the coal sample container and the reference container reach gas pressure equilibrium (first gas equilibrium pressure). The connection between the coal sample container and the reference container is disconnected. At the same time, the coal sample in the coal sample container adsorbs the methane gas inside (to achieve pressure equilibrium).

[0066] After evacuating the reference container again using a vacuum pump, connect the carbon dioxide cylinder to the reference container's injection port and inject carbon dioxide gas into the reference container. When the carbon dioxide pressure inside the reference container reaches the second preset pressure... After closing the carbon dioxide cylinder, connect the coal sample container and the reference container, allowing the carbon dioxide in the reference container to flow freely into the coal sample container until the coal sample container and the reference container reach gas pressure equilibrium (second gas equilibrium pressure). Disconnect the coal sample container and the reference container.

[0067] It should be noted that the gas pressure inside the coal sample container is monitored in real time by a first pressure sensor installed on the coal sample container. After the coal sample in the coal sample container has reached pressure equilibrium by adsorbing the methane gas, the reference container and the coal sample container are connected, allowing carbon dioxide in the reference container to flow freely into the coal sample container until the coal sample container and the reference container reach gas pressure equilibrium (second gas equilibrium pressure). ).

[0068] Then, the connection between the coal sample container and the reference container is disconnected, allowing carbon dioxide gas in the coal sample container to displace the methane gas adsorbed on the coal sample. During the gas displacement stage, the real-time parameters (real-time power) of the hot-wire sensor are monitored. or real-time temperature The first pressure sensor monitors the coal sample container in real time. The pressure of every moment Combined with pressure and the real-time temperature inside the coal sample container The thermal conductivity of methane and carbon dioxide was determined, and then the methane concentration in the coal sample container was calculated using a hot-wire concentration model. .

[0069] Step S102: Using the constructed gas adsorption model, based on the methane concentration in the coal sample container... The real-time changes in the data are used to determine the amount of gas adsorbed in the coal sample within the coal sample container.

[0070] The concentration inside the coal sample container was determined using a hot-wire concentration model. methane concentration at time Then, combined with the coal sample container The pressure of every moment and the absolute temperature inside the coal sample container The adsorption amounts of methane and carbon dioxide by the coal sample in the coal sample container were calculated using a gas adsorption model. Specifically, according to the formula:

[0071]

[0072] In the formula, During the gas injection displacement experiment of coal samples The amount of methane adsorbed by the coal sample at any given time; The reference tank volume for the coal sample gas injection displacement experimental device; The first preset pressure of methane injected into the reference tank of the coal sample gas injection displacement experimental device during the sample gas injection displacement experiment; The first gas equilibrium pressure in the coal sample container and the reference container during the coal sample gas displacement experiment; Standard temperature, Standard atmospheric pressure The absolute temperature during the gas injection and displacement experiment of the coal sample;

[0073] During the gas injection displacement experiment of coal samples The amount of carbon dioxide adsorbed by the coal sample at any given time; The second preset pressure for injecting carbon dioxide into the reference tank during the coal sample gas displacement experiment; The second gas equilibrium pressure in the coal sample container and the reference container during the coal sample gas displacement experiment;

[0074] The free space volume inside the coal sample container during the coal sample gas displacement experiment; During the gas displacement experiment of coal samples, the coal sample container methane concentration at time; During the gas displacement experiment of coal samples, the coal sample container The pressure of constant time.

[0075] Therefore, according to the formula:

[0076]

[0077] When determining the gas displacement experiment in the coal sample container Time to Time interval The rate of methane desorption within and Time to The carbon dioxide adsorption rate between time points. Where, During the gas injection displacement experiment of coal samples Time to Time interval The rate of methane desorption within; The free space volume inside the coal sample container before the gas displacement experiment; Standard temperature, Standard atmospheric pressure The absolute temperature during the gas injection and displacement experiment of the coal sample; During the gas displacement experiment of coal samples, the coal sample container The methane concentration at time 1; During the gas displacement experiment of coal samples, the coal sample container The pressure of constant time; During the gas displacement experiment of coal samples, the coal sample container The methane concentration at time 1; During the gas displacement experiment of coal samples, the coal sample container The pressure of constant time;

[0078] During the gas injection displacement experiment of coal samples Time to The rate of carbon dioxide adsorption between time points.

[0079] In this way, the methane concentration in the coal sample container can be monitored using a hot-wire sensor. By monitoring changes in gas concentration in real time and combining them with a constructed hot-line concentration model, this method overcomes the problem that existing sampling and detection methods cannot detect gas concentration in real time during coal sample gas injection displacement experiments. This effectively improves the accuracy of real-time gas concentration detection and avoids pressure disturbances caused by sampling and interference with the gas displacement process. Moreover, it enables dynamic monitoring of gas concentration, adsorption amount, and adsorption rate throughout the entire gas displacement process, providing important support for the research of coal sample gas injection displacement technology.

[0080] This embodiment also provides a gas component detection system based on the hot-wire method, which is used for gas detection during gas displacement using the gas component detection method based on the hot-wire method described in any of the above embodiments. Figure 4 As shown, the system includes:

[0081] Concentration monitoring unit 401 is configured to install a hot-wire sensor in the coal sample container of the coal sample injection displacement experimental device to monitor the methane concentration in the coal sample container during the coal sample displacement experiment. Real-time monitoring of changes;

[0082] Adsorption monitoring unit 402 is configured to use a constructed gas adsorption model to monitor the methane concentration in the coal sample container. The real-time changes in the data are used to determine the amount of gas adsorbed in the coal sample within the coal sample container.

[0083] In the description of this embodiment, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this embodiment, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0084] In this embodiment, the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" mean that a particular feature, structure, material, or characteristic is included in at least one embodiment or example of the present embodiments. Exemplary expressions of the above terms do not necessarily refer to the same embodiment or example in this specification. Also, the described specific features, structures, materials, or characteristics can be incorporated in any suitable way into one or more embodiments or examples.

[0085] The above descriptions are merely some embodiments of the present embodiments, and are not intended to limit the present embodiments. The present embodiments can have various modifications and changes for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present embodiments shall be included in the protection scope of the present embodiments.

Claims

1. A method for detecting a component of a gas based on the hot-wire method, characterized by, Comprising: A hot-wire sensor is arranged in a coal sample tank of a coal sample gas injection displacement experiment device to monitor the change of the methane concentration in the coal sample tank in real time during the coal sample gas injection displacement experiment ; wherein the coal sample gas injection displacement experiment device comprises a gas source, a reference tank, a coal sample tank, a vacuum pumping module and a data acquisition module; the gas source is connected with the reference tank to inject gas into the reference tank; the coal sample tank is provided with a pressure sensor and a hot-wire sensor and is in communication with the reference tank through a gas pipeline; the vacuum pumping module is in communication with the reference tank and the coal sample tank pipeline respectively and can pump the reference tank and the coal sample tank to vacuum during the coal sample gas injection displacement experiment; the data acquisition module is connected with the hot-wire sensor and the pressure sensor to acquire the real-time parameters of the hot-wire sensor and the real-time pressure in the coal sample tank during the coal sample gas injection displacement experiment in real time; wherein when the hot-wire sensor is constant-temperature type, the real-time power of the hot-wire sensor is acquired ; when the hot-wire sensor is constant-current type, the real-time temperature and the real-time power of the hot-wire sensor are acquired; the coal sample tank and the reference tank are located in the same constant-temperature environment during the coal sample gas injection displacement experiment; By constructing a gas adsorption model, based on the methane concentration in the coal sample container... The real-time changes in the data are used to determine the amount of gas adsorbed in the coal sample within the coal sample container; the gas adsorption model is as follows: In the formula, is the amount of methane adsorbed by the coal sample at the time t during the coal sample gas injection displacement experiment is the amount of methane adsorbed by the coal sample at the time t during the coal sample gas injection displacement experiment is the reference tank volume of the coal sample gas injection displacement experiment device is the first preset pressure of the methane injected into the reference tank of the coal sample gas injection displacement experiment device during the coal sample gas injection displacement experiment is the first gas equilibrium pressure in the coal sample tank and the reference tank during the coal sample gas injection displacement experiment is the standard temperature, is the standard atmospheric pressure, is the absolute temperature during the coal sample gas injection displacement experiment; the amount of carbon dioxide adsorbed by the coal sample at each time instant during the gas injection displacement experiment on the coal sample; the amount of carbon dioxide adsorbed by the coal sample at each time instant during the gas injection displacement experiment on the coal sample; a second preset pressure of carbon dioxide injected into the reference tank during the gas injection displacement experiment on the coal sample; a second gas equilibrium pressure in the coal sample tank and the reference tank during the gas injection displacement experiment on the coal sample; the free space volume in the coal sample canister during the coal sample gas injection displacement experiment; the free space volume in the coal sample canister during the coal sample gas injection displacement experiment the methane concentration at the moment; the free space volume in the coal sample canister during the coal sample gas injection displacement experiment the pressure at the moment.

2. The method of claim 1, wherein, Based on the constructed hot wire concentration model, and according to the hot wire probe of the hot wire sensor under constant temperature conditions inside the coal sample container... Real-time power at any moment and real-time temperature To determine the contents of the coal sample container during the coal sample injection displacement experiment. methane concentration at time ; wherein the hot-wire concentration model is: In the formula, is the thermal conductivity of methane and carbon dioxide in the coal sample tank during the coal sample gas injection displacement experiment; is the real-time temperature of the hot-wire probe, is the absolute temperature during the coal sample gas injection displacement experiment, is the radius of the hot-wire probe.

3. The method of claim 1, wherein, According to the formula: Calculating the free space volume in a coal sample canister for gas displacement experiments ; wherein is the reference tank volume for the coal sample gas injection displacement experiment device; is the gas pressure change in the reference tank; is the gas pressure change in the coal sample tank.

4. The method of claim 1, wherein, The gas adsorption model also includes: wherein is the methane desorption rate within the time interval from time to time is the time interval from time to time is the free space volume within the coal sample canister during the coal sample gas injection displacement experiment; is the standard temperature, is the standard atmospheric pressure, is the absolute temperature during the coal sample gas injection displacement experiment; is the methane concentration within the coal sample canister at time during the coal sample gas injection displacement experiment; is the pressure within the coal sample canister at time during the coal sample gas injection displacement experiment; is the methane concentration within the coal sample canister at time during the coal sample gas injection displacement experiment; is the pressure within the coal sample canister at time during the coal sample gas injection displacement experiment; The carbon dioxide adsorption rate between the time point of time point to time point.

5. The method of claim 4, wherein, In the coal sample gas injection displacement experiment, the coal sample tank and the reference tank are continuously vacuumed, helium gas with a preset pressure is injected into the reference tank, the reference tank is connected with the coal sample tank, and the free space volume in the coal sample tank is determined according to the gas pressure changes in the reference tank and the coal sample tank ; After the reference tank is vacuumed, inject methane at a first preset pressure After the reference tank is vacuumed, inject methane at a first preset pressure After the reference tank is vacuumed, inject methane at a first preset pressure The reference tank is vacuumed again, and the second preset pressure of carbon dioxide is injected After that, the coal sample tank is connected with the reference tank again, and the second gas equilibrium pressure is reached , and the coal sample tank is closed to perform gas displacement. In response to gas displacement occurring in the coal sample canister, the pressure in the coal sample canister is monitored in real time Real-time parameters of a hot-wire sensor provided on the coal sample canister are recorded simultaneously. The methane concentration in the coal sample tank is calculated by the hot-wire concentration model according to the real-time parameters of the hot-wire sensor, and the adsorption amounts of the coal sample in the coal sample tank to methane and carbon dioxide are respectively calculated by the gas adsorption model.

6. A gas component detection system based on the hot-wire method, characterized by The system for detecting gas during gas displacement by using the gas component detection method based on the hot-wire method in any one of claims 1-5 comprises: The concentration monitoring unit is configured to install a hot-wire sensor in the coal sample container of the coal sample injection displacement experimental device to monitor the methane concentration in the coal sample container during the coal sample displacement experiment. Real-time monitoring of changes; The adsorption monitoring unit is configured to determine the gas adsorption amount of the coal sample in the coal sample tank according to real-time changes in the methane concentration in the coal sample tank by constructing a gas adsorption model. of the coal sample in the coal sample tank.

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