A non-methane total hydrocarbon dilution detection device and its detection method

Abstract

This invention discloses a non-methane total hydrocarbon dilution detection device and its detection method, relating to the field of waste gas detection technology. The device includes a sampling pipeline, a return pipeline, a diversion valve, a collection pump, an air pipeline, a mixing pipeline, an electromagnetic multi-way valve, and a flame ionization detector (FID). The electromagnetic multi-way valve is connected to a gas storage valve. A first sensor and a second sensor within the gas storage valve are communicatively connected to the electromagnetic multi-way valve. Remaining mixed gas can be temporarily stored in the gas storage valve. The fullness or deficiency of the mixed gas in the gas storage valve is detected by the first and second sensors. Under the pressure of the floating pressure control module, the mixed gas maintains a certain pressure, which helps to push the mixed gas back into the FID for detection. This improves upon the problem in existing technologies where the amount of mixed gas allowed to enter the FID detector is limited, preventing the utilization of excess mixed gas and resulting in low energy efficiency.

Description

Technical Field

[0001] This invention relates to the field of exhaust gas detection technology, and in particular to a non-methane total hydrocarbon dilution detection device and its detection method. Background Technology

[0002] Non-methane hydrocarbons are gaseous or liquid at room temperature and are highly volatile, causing environmental pollution. Therefore, the detection of non-methane hydrocarbons is a necessary environmental monitoring measure.

[0003] During the non-methane total hydrocarbon detection, exhaust gas is drawn in using a high-flow-rate sampling pump (approximately 7 L / min) to generate a high flow velocity. Most of the exhaust gas (approximately 6.65 L / min) is then returned to the exhaust gas duct via a return pipe. The remaining exhaust gas (approximately 0.35 L / min) is then mixed with compressed air (approximately 3.15 L / min) as a dilution gas and flows into a flame ionization detector (FID detector) for detection.

[0004] FID detectors generally only allow mixed gas to enter at a flow rate of tens of milliliters per minute. Therefore, the main methods for handling excess mixed gas are venting or returning it to the exhaust gas pipeline for treatment (refer to the online dilution monitoring device for total hydrocarbons in exhaust gas disclosed in CN107024377B, or the non-methane total hydrocarbon detection device and method based on dilution technology disclosed in CN117147671A).

[0005] Existing technologies do not utilize excess mixed gas; therefore, the high-flow-rate sampling pump and the compressed air motor must operate continuously, resulting in low energy efficiency. Summary of the Invention

[0006] One of the objectives of this invention is to improve the problem of low energy efficiency caused by the limited amount of mixed gas allowed to enter the FID detector in the prior art, which prevents the utilization of excess mixed gas.

[0007] The second objective of this invention is to provide a method for detecting non-methane total hydrocarbons through dilution.

[0008] To achieve one of the above objectives, the present invention adopts the following technical solution: a non-methane total hydrocarbon dilution detection device, comprising a sampling pipeline, a return pipeline, a diversion valve, a sampling pump, an air pipeline, a mixing pipeline, an electromagnetic multi-way valve, and a hydrogen flame ionization detector, wherein the sampling pump is disposed on the sampling pipeline, and the sampling pipeline is connected to the return pipeline through the diversion valve.

[0009] The sampling pipeline, the air pipeline, and the mixing pipeline are respectively connected to the electromagnetic multi-way valve, and the mixing pipeline is connected to the hydrogen flame ionization detector.

[0010] The electromagnetic multi-way valve is also connected to an air storage valve. The air storage valve includes an air hole and an air storage chamber. The air hole connects the electromagnetic multi-way valve and the air storage chamber. A floating pressure control module is slidably arranged in the air storage chamber. A first sensor is arranged at the lower end of the air storage chamber, and a second sensor is arranged at the upper end of the air storage chamber. The first sensor and the second sensor are communicatively connected to the electromagnetic multi-way valve.

[0011] A magnetorheological fluid chamber is provided above the gas storage chamber, and a damping plug is slidably disposed in the magnetorheological fluid chamber. The damping plug is connected to the floating pressure control module through a rod, and an electromagnet ring is provided on the side end of the damping plug.

[0012] In the above technical solution, during use, the sampling pump draws waste gas into the diversion valve in the sampling pipeline. A portion of the waste gas flows into the return pipeline, while the remaining waste gas enters the electromagnetic multi-way valve, where it mixes with air (used as a dilution gas) in the air pipeline to dilute the volume concentration of non-methane total hydrocarbons in the waste gas. Subsequently, a portion of the mixed gas enters the hydrogen flame ionization detector for detection. The remaining mixed gas enters the storage valve for temporary storage.

[0013] The mixed gas enters the storage chamber through the vent of the storage valve, pushing the floating pressure control module upwards. Then, when the second sensor detects the damping plug, it controls the solenoid multi-way valve to close the sampling line and the air line. At this time, the floating pressure control module forces the mixed gas in the storage chamber back to the solenoid multi-way valve, allowing the mixed gas to enter the flame ionization detector (FID detector) for detection. Subsequently, when the first sensor detects the floating pressure control module, it controls the solenoid multi-way valve to open the sampling line and the air line.

[0014] The beneficial effects of this invention are:

[0015] First, the remaining mixed gas can be temporarily stored in the gas storage valve. The fullness or deficiency of the mixed gas in the gas storage valve can also be detected by the first and second sensors. Under the pressure of the floating pressure control module with its own weight, the remaining mixed gas can maintain a certain pressure, which helps to push the remaining mixed gas back into the hydrogen flame ionization detector for detection. This improves the problem in the prior art that the amount of mixed gas allowed to enter the FID detector is limited, and the excess mixed gas cannot be utilized, resulting in low energy utilization.

[0016] Secondly, the floating pressure control module is connected to the damping plug in the magnetorheological fluid chamber. When the electromagnet ring at the side end of the damping plug is energized to generate a magnetic field, a rheological effect occurs in the magnetorheological fluid between the electromagnet ring and the wall of the magnetorheological fluid chamber, forming a plastic Bingham fluid. At this time, the mixed gas requires greater pressure to push the floating pressure control module because the resistance to the upward movement of the floating pressure control module increases. This allows for adaptation to changes in the mixed gas pressure, enabling the utilization of residual mixed gas at different pressures and improving the problem of low energy efficiency.

[0017] It should be noted that because the sampling pump in the sampling pipeline has different requirements than the air pump in the air pipeline, or the pipe diameters used are different, even with the same equipment, the pressure of the mixed gas may be different, and there is no accurate standard. Therefore, a gas storage structure that can adapt to changes in the pressure of the mixed gas is needed.

[0018] Furthermore, in this embodiment of the invention, the gas storage chamber and the magnetorheological fluid chamber are separated by a partition plate.

[0019] Furthermore, in this embodiment of the invention, the non-methane total hydrocarbon dilution detection device further includes a hydrogen pipeline, which is connected to the hydrogen flame ionization detector.

[0020] Furthermore, in this embodiment of the invention, the hydrogen pipeline is connected to a hydrogen cylinder, and a first flow meter is installed on the hydrogen pipeline.

[0021] Furthermore, in this embodiment of the invention, the air pipeline is connected to an air pump, and a second flow meter is installed on the air pipeline.

[0022] Furthermore, in this embodiment of the invention, an air filter is provided on the air duct.

[0023] Furthermore, in this embodiment of the invention, a third flow meter is provided on the mixing pipeline.

[0024] Furthermore, in this embodiment of the invention, a fourth flow meter is provided on the return pipeline.

[0025] To achieve the second objective mentioned above, the present invention adopts the following technical solution: a method for detecting non-methane total hydrocarbons by dilution, wherein the method is based on the non-methane total hydrocarbon dilution detection device described in one of the objectives of the invention, and the method includes the following steps:

[0026] (S1) The sampling pump draws the waste gas into the sampling pipeline, and then enters the diversion valve. Part of the waste gas enters the return pipeline, and the remaining waste gas enters the electromagnetic multi-way valve. At the same time, external air is compressed and enters the electromagnetic multi-way valve through the air pipeline to mix with the waste gas in order to dilute the volume concentration of non-methane total hydrocarbons in the waste gas.

[0027] (S2) Part of the mixed gas enters the hydrogen flame ionization detector through the mixing pipe for detection.

[0028] (S3) The remaining mixed gas enters the storage chamber through the air hole of the storage valve to push the floating pressure control module upward. When the second sensor detects the damping plug, it controls the electromagnetic multi-way valve to close the sampling pipeline and the air pipeline, and the sampling pump stops working.

[0029] (S4) At this time, the floating pressure control module compresses the mixed gas in the gas storage chamber back to the electromagnetic multi-way valve, so that the mixed gas enters the hydrogen flame ionization detector for detection.

[0030] When the first sensor detects the floating pressure control module, it controls the solenoid multi-way valve to open the sampling pipeline and the air pipeline, and the sampling pump starts working again, repeating the above steps (S1), (S2) and (S3).

[0031] Furthermore, in the embodiments of the present invention, in the above steps, when the pressure of the mixed gas in the gas storage valve is adjusted, the electromagnetic ring of the damping plug is energized to generate a magnetic field, thereby causing a rheological effect between the electromagnetic ring and the magnetorheological fluid cavity wall to form a plastic Bingham fluid, so as to change the resistance of the floating pressure control module to move upward.

[0032] It should be noted that because the sampling pump in the sampling pipeline has different requirements than the air pump in the air pipeline, or the pipe diameters used are different, even with the same equipment, the pressure of the mixed gas may be different, and there is no accurate standard. Therefore, a gas storage structure that can adapt to changes in the pressure of the mixed gas is needed. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the gas path connection of the non-methane total hydrocarbon dilution detection device according to an embodiment of the present invention.

[0034] Figure 2 This is a schematic diagram of the structure of the gas storage valve in an embodiment of the present invention.

[0035] Figure 3 This is another structural schematic diagram of the gas storage valve according to an embodiment of the present invention.

[0036] 1. Sampling line, 2. Return line, 3. Diverter valve, 4. Acquisition pump, 5. Air line, 6. Mixing line, 7. Hydrogen flame ionization detector, 8. Electromagnetic multi-way valve, 9. Gas storage valve, 10. Hydrogen line, 11. Hydrogen cylinder, 12. First flow meter, 13. Air pump, 14. Second flow meter, 15. Air filter, 16. Third flow meter, 17. Fourth flow meter;

[0037] 9.1. Air vent; 9.2. Air storage chamber; 9.3. Floating pressure control module; 9.4. First sensor; 9.5. Second sensor; 9.6. Partition plate; 9.7. Damping plug; 9.8. Electromagnetic ring. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the present invention clear and complete, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some, not all, embodiments of the present invention, and are merely illustrative of the embodiments of the present invention. They are not intended to limit 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.

[0039] In the description of this invention, it should be noted that the terms "center," "middle," "upper," "lower," "left," "right," "inner," "outer," "top," "bottom," "side," "vertical," and "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "a," "first," "second," "third," "fourth," "fifth," and "sixth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0040] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] For purposes of simplicity and illustration, the principles of the embodiments are described primarily by way of example. In the following description, numerous specific details are set forth to provide a thorough understanding of the embodiments. However, it will be apparent to those skilled in the art that these embodiments may not be limited to these specific details in practice. In some instances, well-known non-methane total hydrocarbon dilution detection methods and structures have not been described in detail to avoid unnecessarily obscuring these embodiments. Furthermore, all embodiments can be used in combination with each other. Example

[0042] It should be noted that the accompanying drawings are part of the content of the instruction manual. The structural shapes, connections, fits, and positional relationships that can be clearly seen in the accompanying drawings should all be understood as part of the content of the instruction manual.

[0043] A non-methane total hydrocarbon dilution detection device, such as Figure 1As shown, it includes a sampling line 1, a return line 2, a diversion valve 3, a sampling pump 4, an air line 5, a mixing line 6, an electromagnetic multi-way valve 8, and a hydrogen flame ionization detector 7 (i.e., FID detector). The sampling pump 4 is installed on the sampling line 1, and the sampling line 1 is connected to the return line 2 through the diversion valve 3.

[0044] Specifically, the electromagnetic multi-way valve 8 is an existing electromagnetically controlled five-way valve.

[0045] Sampling line 1, air line 5 and mixing line 6 are respectively connected to electromagnetic multi-way valve 8, and mixing line 6 is connected to hydrogen flame ionization detector 7.

[0046] like Figure 2 As shown, the electromagnetic multi-way valve 8 is also connected to an air storage valve 9. The air storage valve 9 includes an air port 9.1 and an air storage chamber 9.2. The air port 9.1 connects the electromagnetic multi-way valve 8 and the air storage chamber 9.2. A floating pressure control module 9.3 is slidably installed in the air storage chamber 9.2. A first sensor 9.4 is installed at the lower end of the air storage chamber 9.2, and a second sensor 9.5 is installed at the upper end of the air storage chamber 9.2. The first sensor 9.4 and the second sensor 9.5 are communicatively connected to the electromagnetic multi-way valve 8.

[0047] like Figure 3 As shown, a magnetorheological fluid chamber is provided above the gas storage chamber 9.2, and a damping plug 9.7 is slidably installed inside the magnetorheological fluid chamber. The damping plug 9.7 is connected to the floating pressure control module 9.3 through the rod body, and an electromagnet ring 9.8 is provided on the side end of the damping plug 9.7.

[0048] The chamber is filled with magnetorheological fluid. It should be noted that magnetorheological fluid is a novel type of fluid with controllable flowability and is a relatively active area of ​​research in smart materials. In the absence of an external magnetic field, it exhibits low-viscosity Newtonian fluid characteristics. Under an applied magnetic field, it exhibits high-viscosity, low-flowability Bingham fluid characteristics. There is a correlation between the viscosity of the liquid and the magnetic flux, meaning that the viscosity of the liquid is related to the magnitude of the electric current.

[0049] Implementation: Pump 4 draws waste gas into the diversion valve 3 in sampling pipeline 1. Part of the waste gas flows into return pipeline 2, and the remaining waste gas enters electromagnetic multi-way valve 8, where it mixes with air (used as dilution gas) in the air pipeline to dilute the volume concentration of non-methane total hydrocarbons in the waste gas. Then, part of the mixed gas enters hydrogen flame ionization detector 7 for detection. The remaining mixed gas enters storage valve 9 for temporary storage.

[0050] The mixed gas enters the storage chamber 9.2 through the vent 9.1 of the storage valve 9, pushing the floating pressure control module 9.3 upward. Then, when the second sensor 9.5 detects the damping plug 9.7 (the mixed gas in the storage chamber 9.2 is full), it controls the electromagnetic multi-way valve 8 to close the sampling line 1 and the air line 5 (meaning that the sampling pump 4 and the air pump 13 of the air line 5 do not need to work). At this time, the floating pressure control module 9.3 forces the mixed gas in the storage chamber 9.2 back to the electromagnetic multi-way valve 8, allowing the mixed gas to enter the flame ionization detector 7 (FID detector) for detection. Then, when the first sensor 9.4 detects the floating pressure control module 9.3 (the mixed gas in the storage chamber 9.2 is deficient), it controls the electromagnetic multi-way valve 8 to open the sampling line 1 and the air line 5.

[0051] One of the advantages of this invention is that the remaining mixed gas can be temporarily stored in the gas storage valve 9, and the full or empty state of the mixed gas in the gas storage valve 9 can be detected by the first sensor 9.4 and the second sensor 9.5. Under the pressure of the floating pressure control module 9.3 by its own weight, the remaining mixed gas can maintain a certain pressure, which helps to push the remaining mixed gas back into the hydrogen flame ionization detector 7 for detection. This improves the problem in the prior art that the limited mixed gas allowed to enter the FID detector cannot be utilized, resulting in low energy utilization.

[0052] A second advantage of this invention is that the floating pressure control module 9.3 is connected to the damping plug 9.7 in the magnetorheological fluid chamber. When the electromagnet ring 9.8 at the side end of the damping plug 9.7 is energized to generate a magnetic field, a rheological effect occurs in the magnetorheological fluid between the electromagnet ring 9.8 and the wall of the magnetorheological fluid chamber, forming a plastic Bingham fluid. At this time, the mixed gas requires greater pressure to push the floating pressure control module 9.3 because the resistance to the upward movement of the floating pressure control module 9.3 increases. This allows for adaptation to changes in the mixed gas pressure, enabling the utilization of residual mixed gas at different pressures and improving the problem of low energy efficiency.

[0053] It should be noted that because the sampling pump 4 of sampling pipeline 1 and the air pump 13 of air pipeline 5 have different requirements, or the pipe diameters of the pipelines used are different, even if the equipment is the same, the pressure of the mixed gas may be different and there is no accurate standard. Therefore, a gas storage structure that can adapt to changes in the pressure of the mixed gas is needed.

[0054] Specifically, such as Figure 3 As shown, the gas storage chamber 9.2 and the magnetorheological fluid chamber are separated by a partition plate 9.6.

[0055] Specifically, such as Figure 1 As shown, the non-methane total hydrocarbon dilution detection device also includes a hydrogen pipeline 10, which is connected to the hydrogen flame ionization detector 7.

[0056] More specifically, such as Figure 1 As shown, hydrogen pipeline 10 is connected to hydrogen cylinder 11, and a first flow meter 12 is installed on hydrogen pipeline 10.

[0057] Specifically, such as Figure 1 As shown, air pipe 5 is connected to air pump 13, and a second flow meter 14 is installed on air pipe 5.

[0058] More specifically, such as Figure 1 As shown, an air filter 15 is installed on the air duct 5.

[0059] Specifically, such as Figure 1 As shown, a third flow meter 16 is installed on the mixing pipeline 6. A fourth flow meter 17 is installed on the return pipeline 2. Example

[0060] A method for detecting non-methane total hydrocarbons by dilution, the method being based on the non-methane total hydrocarbon dilution detection device described in Example 1 above, and comprising the following steps:

[0061] (S1) The sampling pump 4 draws the waste gas into the sampling pipeline 1, and then enters the diversion valve 3. Part of the waste gas enters the return pipeline 2, and the remaining waste gas enters the electromagnetic multi-way valve 8. At the same time, external air is compressed and enters the electromagnetic multi-way valve 8 through the air pipeline to mix with the waste gas in order to dilute the volume concentration of non-methane total hydrocarbons in the waste gas.

[0062] (S2) Part of the mixed gas enters the hydrogen flame ionization detector 7 through the mixing pipe for detection.

[0063] (S3) The remaining mixed gas enters the gas storage chamber 92 through the air hole 9.1 of the gas storage valve 9 to push the floating pressure control module 93 upward. When the second sensor 9.5 detects the damping plug 9.7, it controls the electromagnetic multi-way valve 8 to close the sampling pipeline 1 and the air pipeline 5, and the sampling pump 4 stops working.

[0064] (S4) At this time, the floating pressure control module 9.3 compresses the mixed gas in the gas storage chamber 9.2 back to the electromagnetic multi-way valve 8, so that the mixed gas enters the hydrogen flame ionization detector 7 for detection.

[0065] When the first sensor 9.4 detects the floating pressure control module 9.3, it controls the solenoid multi-way valve 8 to open the sampling pipeline 1 and the air pipeline 5, and the sampling pump 4 starts working again, repeating the above steps (S1), (S2) and (S3).

[0066] The remaining mixed gas of the present invention can be temporarily stored in the gas storage valve 9, and under the pressure of its own weight, the remaining mixed gas can maintain a certain pressure, which helps to push the remaining mixed gas back into the hydrogen flame ionization detector 7 for detection. This improves the problem in the prior art that the limited mixed gas allowed to enter the FID detector cannot be utilized, resulting in low energy utilization.

[0067] Specifically, in the above steps, when air line 5 is closed, air pump 13 stops working.

[0068] Specifically, in the above steps, when the pressure of the mixed gas in the gas storage valve 9 is adjusted, the electromagnet ring 9.8 of the damping plug 9.7 is energized to generate a magnetic field. This causes a rheological effect between the electromagnet ring 9.8 and the magnetorheological fluid cavity wall, forming a plastic Bingham fluid. This changes the resistance to the upward movement of the floating pressure control module 9.3. At this point, the mixed gas requires greater pressure to push the floating pressure control module 9.3 because the resistance to its upward movement increases. This adapts to changes in the mixed gas pressure, enabling the utilization of residual mixed gas at different pressures and improving the problem of low energy efficiency.

[0069] It should be noted that because the sampling pump 4 of sampling pipeline 1 and the air pump 13 of air pipeline 5 have different requirements, or the pipe diameters of the pipelines used are different, even if the equipment is the same, the pressure of the mixed gas may be different and there is no accurate standard. Therefore, a gas storage structure that can adapt to changes in the pressure of the mixed gas is needed.

[0070] Although the illustrative specific embodiments of the present invention have been described above to enable those skilled in the art to understand the invention, the invention is not limited to the scope of the specific embodiments. For those skilled in the art, all inventions utilizing the concept of the present invention are protected as long as various variations are within the spirit and scope of the invention as defined and determined by the appended claims.

Claims

1. A non-methane total hydrocarbon dilution detection device, comprising a sampling pipeline, a return pipeline, a diversion valve, a sampling pump, an air pipeline, a mixing pipeline, an electromagnetic multi-way valve, and a hydrogen flame ionization detector, wherein the sampling pump is disposed on the sampling pipeline, and the sampling pipeline is connected to the return pipeline through the diversion valve; The sampling pipeline, the air pipeline, and the mixing pipeline are respectively connected to the electromagnetic multi-way valve, and the mixing pipeline is connected to the hydrogen flame ionization detector; Its features are, The electromagnetic multi-way valve is also connected to an air storage valve. The air storage valve includes an air hole and an air storage chamber. The air hole connects the electromagnetic multi-way valve and the air storage chamber. A floating pressure control module is slidably arranged in the air storage chamber. A first sensor is arranged at the lower end of the air storage chamber, and a second sensor is arranged at the upper end of the air storage chamber. The first sensor and the second sensor are communicatively connected to the electromagnetic multi-way valve. A magnetorheological fluid chamber is provided above the gas storage chamber, and a damping plug is slidably provided in the magnetorheological fluid chamber. The damping plug is connected to the floating pressure control module through a rod, and an electromagnet ring is provided on the side end of the damping plug. After the electromagnet ring is energized to generate a magnetic field, the magnetorheological fluid between the electromagnet ring and the wall of the magnetorheological fluid cavity undergoes a rheological effect, forming a plastic Bingham fluid, which changes the resistance to the upward movement of the floating pressure control module.

2. The non-methane total hydrocarbon dilution detection device according to claim 1, characterized in that, The gas storage chamber and the magnetorheological fluid chamber are separated by a partition plate.

3. The non-methane total hydrocarbon dilution detection device according to claim 1, characterized in that, The non-methane total hydrocarbon dilution detection device also includes a hydrogen pipeline, which is connected to the hydrogen flame ionization detector.

4. The non-methane total hydrocarbon dilution detection device according to claim 3, characterized in that, The hydrogen pipeline is connected to the hydrogen cylinder, and a first flow meter is installed on the hydrogen pipeline.

5. The non-methane total hydrocarbon dilution detection device according to claim 1, characterized in that, The air pipeline is connected to the air pump, and a second flow meter is installed on the air pipeline.

6. The non-methane total hydrocarbon dilution detection device according to claim 5, characterized in that, An air filter is installed on the air duct.

7. The non-methane total hydrocarbon dilution detection device according to claim 1, characterized in that, A third flow meter is installed on the mixing pipeline.

8. The non-methane total hydrocarbon dilution detection device according to claim 1, characterized in that, A fourth flow meter is installed on the return pipeline.

9. A method for dilution detection of non-methane total hydrocarbons, characterized in that, The non-methane total hydrocarbon dilution detection method is based on the non-methane total hydrocarbon dilution detection device according to any one of claims 1-8, and the non-methane total hydrocarbon dilution detection method includes the following steps: (S1) The sampling pump draws the waste gas into the sampling pipeline, and then enters the diversion valve. Part of the waste gas enters the return pipeline, and the remaining waste gas enters the electromagnetic multi-way valve. At the same time, external compressed air enters the electromagnetic multi-way valve through the air pipeline and mixes with the waste gas to dilute the volume concentration of non-methane total hydrocarbons in the waste gas. (S2) Part of the mixed gas enters the hydrogen flame ionization detector through the mixing pipe for detection. (S3) The remaining mixed gas enters the storage chamber through the air hole of the storage valve to push the floating pressure control module upward. When the second sensor detects the damping plug, it controls the electromagnetic multi-way valve to close the sampling pipeline and the air pipeline, and the sampling pump stops working. (S4) At this time, the floating pressure control module compresses the mixed gas in the gas storage chamber back to the electromagnetic multi-way valve, so that the mixed gas enters the hydrogen flame ionization detector for detection. When the first sensor detects the floating pressure control module, it controls the solenoid multi-way valve to open the sampling pipeline and the air pipeline, and the sampling pump starts working again, repeating the above steps (S1), (S2) and (S3).

10. The method for detecting non-methane total hydrocarbons by dilution according to claim 9, characterized in that, In the above steps, when the pressure of the mixed gas in the gas storage valve is adjusted, the electromagnetic ring of the damping plug is energized to generate a magnetic field, thereby causing a rheological effect between the electromagnetic ring and the magnetorheological fluid cavity wall, forming a plastic Bingham fluid, which changes the resistance of the floating pressure control module to move upward.

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