Coke oven gas pipeline negative pressure sampling system and method

Abstract

The application discloses a coke oven gas pipeline negative pressure sampling system and method, which comprises a coke oven gas main pipeline and a sampling main pipeline connected with the coke oven gas main pipeline. The pipe wall of the coke oven gas main pipeline is provided with an insulation layer. A sampling head unit is connected to the sampling main pipeline. The sampling head unit comprises a valve and an anti-blocking sampling head arranged in series on the sampling main pipeline. The sampling head unit is connected in series or parallel with a booster unit. The air inlet end of the booster unit is communicated with the end of the sampling main pipeline away from the anti-blocking sampling head. The air inlet and air outlet of the booster unit are respectively provided with a one-way valve. The booster unit is connected in series with a filtering and purifying unit. The filtering and purifying unit is connected in series with a flow regulating unit. The flow regulating unit is used for detecting the sampling flow in real time and feeding back to a controller. The controller adjusts the opening degree of the flow regulating valve, so that the sampling flow is stabilized in a preset range.

Description

Technical Field

[0001] This invention belongs to the field of coke oven gas sampling technology, specifically relating to a negative pressure sampling system and method for coke oven gas pipelines. Background Technology

[0002] Coke oven gas is an important byproduct of the coking process. Its composition is complex, containing combustible gases such as hydrogen, methane, and carbon monoxide, as well as impurities like tar, naphthalene, and dust. Component analysis of coke oven gas is a crucial step in gas recovery and utilization, and ensuring environmentally compliant emissions. Accurate sampling is a prerequisite for component analysis.

[0003] Coke oven gas pipelines are often under negative pressure during operation, and traditional sampling methods have many problems: First, the negative pressure environment makes it difficult for the gas to be discharged smoothly, resulting in small and unstable sampling flow rates, or even no sampling at all; second, tar and dust in the gas easily clog the sampling head and pipeline, affecting the continuity of sampling and sample purity; third, large pressure fluctuations during sampling cause changes in sample composition, affecting the accuracy of analysis; fourth, existing sampling devices lack targeted negative pressure balancing and impurity handling designs, and are suitable for positive or atmospheric pressure pipelines, which cannot meet the sampling requirements of coke oven gas pipelines under negative pressure conditions.

[0004] Therefore, there is an urgent need to design a negative pressure sampling system and method for coke oven gas pipelines that can solve the difficulties of negative pressure sampling, have good anti-blocking effect, and provide accurate sampling. Summary of the Invention

[0005] The purpose of this invention is to provide a negative pressure sampling system and method for coke oven gas pipelines to solve the problems mentioned in the background art.

[0006] The objective of this invention is achieved through the following technical solution: a negative pressure sampling system for coke oven gas pipelines, comprising a main coke oven gas pipeline and a sampling main pipe connected to the main coke oven gas pipeline, wherein the pipe wall of the main coke oven gas pipeline is provided with a heat insulation layer, and a sampling head unit is connected to the sampling main pipe, wherein the sampling head unit comprises a valve and an anti-clogging sampling head arranged in series on the sampling main pipe.

[0007] The sampling head unit is connected in series with the pressurization unit. The air inlet of the pressurization unit is connected to the end of the sampling main tube away from the anti-clogging sampling head. One-way valves are installed at the air inlet and air outlet of the pressurization unit, respectively.

[0008] The pressurization unit is connected in series with the filtration and purification unit, which in turn is connected in series with the flow regulation unit. The flow regulation unit detects the sampled flow rate in real time and feeds it back to the controller. The controller adjusts the opening of the flow regulation valve to stabilize the sampled flow rate within a preset range.

[0009] Furthermore, the anti-clogging sampling head is configured with a porous sand core filter structure, and the surface is provided with a polytetrafluoroethylene anti-stick filter membrane.

[0010] Furthermore, the booster unit includes a booster pump and a pressure sensor connected in series with the booster pump;

[0011] The booster pump is a miniature oil-free booster pump. The input end is connected to the end of the sampling main pipe away from the anti-clogging sampling head. Both the inlet and outlet of the booster pump are equipped with check valves.

[0012] Furthermore, the booster unit is electrically connected to a controller, which is a PLC controller. The controller adjusts the output power of the booster pump according to the pressure sensor detection value of the sampling main pipe, so that the pressure in the sampling pipeline is maintained at 0.02-0.1MPa, effectively balancing the negative pressure environment of the coke oven gas pipeline and ensuring the smooth output of the gas.

[0013] Furthermore, the filtration and purification unit includes a first filter component and a second filter component connected in series.

[0014] The filtration and purification unit is configured to be one or two sets connected in series with the pressurization unit.

[0015] Furthermore, the first filter component is a dust filter component, which is a tar and dust filter equipped with a glass fiber filter membrane, with a filtration accuracy ≥0.24μm;

[0016] The second filtration component is a precision filtration component, which uses a polytetrafluoroethylene (PTFE) filter membrane with a filtration accuracy of 0.1-0.3 μm.

[0017] Furthermore, the outlet end of the flow regulating unit is connected to the sampling and storage unit, which includes a sample receiver or absorption device, and the input end of the sample receiver or absorption device is connected to the output end of the flow regulating unit.

[0018] The sample receiver or absorption device uses an aluminum foil composite film and a polypropylene (PP) dual-valve gas sampling bag.

[0019] A method for negative pressure sampling of coke oven gas pipelines based on a coke oven gas pipeline negative pressure sampling system includes the following steps;

[0020] S1 system pretreatment: Prepare a gas absorption device or system in advance. The absorption device or system mainly consists of an aluminum foil composite film + polypropylene PP double valve gas sampling bag. The air in the sampling bag is discharged by multiple compressions; or a vacuum pump is used to vacuum the sampling bag to reduce resistance during the sampling process.

[0021] S2 Pressure Pre-regulation: The controller uses the pressure sensor on the sampling main pipe and activates the booster unit, adjusting its output power to bring the pressure in the sampling main pipe to a preset equilibrium pressure value of 0.02-0.1 MPa. When the absolute value of the negative pressure in the pipeline is ≥0.05 MPa, the equilibrium pressure value is set to 0.05-0.1 MPa; when the absolute value of the negative pressure in the pipeline is <0.05 MPa, the equilibrium pressure value is set to 0.02-0.05 MPa, ensuring pressure balance.

[0022] S3 Sampling Flow Rate Adjustment: Open the flow rate adjustment valve, and the controller adjusts the valve opening according to the flow meter detection value to stabilize the sampling flow rate at the gas flow rate specified in the standard, ensuring a uniform sampling rate;

[0023] S4 staged sampling: First, open the valve on the sampling pipeline and allow the gas flow to pass through the sampling main pipe, pressurization unit, filtration and purification unit, and flow regulation unit for 5-10 minutes to flush the pipeline and remove air and residual impurities. Then, connect the gas sampling and absorption device for sampling. During the sampling process, the gas pressure and flow rate can be monitored in real time through pressure sensors and flow meters. When the pressure fluctuation exceeds ±0.01MPa or the flow fluctuation exceeds ±10mL / min, the power of the pressurization unit and the opening of the flow regulation valve can be adjusted to maintain sampling stability. When the sampling volume meets the detection requirements or reaches the maximum volume of the sampling bag, the controller closes the flow regulation valve and the pressurization unit.

[0024] S5 Sample Sealing: After sampling, close the inlet and outlet valves of the sampling bag to complete sample sealing, and subsequent sample component analysis can be carried out.

[0025] An application of a negative pressure sampling method for coke oven gas pipelines based on a negative pressure sampling system for coke oven gas pipelines is presented. This method addresses the problems of difficult sampling, unstable flow, and easy contamination of samples under negative pressure conditions, thereby achieving efficient and accurate sampling.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] This invention effectively balances the negative pressure environment of coke oven gas pipelines by combining a pressurization unit with a pressure regulating component, solving the problems of difficult sampling and unstable flow under negative pressure conditions, and ensuring continuous and efficient sampling process.

[0028] This invention's anti-clogging sampling head employs a porous sand core filter device with a polytetrafluoroethylene (PTFE) anti-sticking filter membrane on its surface. This ensures gas flow while blocking large particulate impurities, effectively preventing tar and impurities from adhering, avoiding pipeline blockage, and extending equipment lifespan.

[0029] The filtration and purification unit of this invention adopts a two-stage filtration design to remove tar, dust and fine impurities in sequence, ensuring the purity of the sample and providing a reliable guarantee for subsequent component analysis.

[0030] This invention achieves accurate control of the sampling process through a PLC controller, monitors and dynamically adjusts parameters such as pressure and flow rate in real time, ensures stable sampling conditions, and improves sampling accuracy.

[0031] The sampling method of this invention further improves the sampling effect through system preprocessing, pressure pre-adjustment, and graded sampling process. It is applicable to coke oven gas pipelines with different negative pressure levels and has wide applicability. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the filtration and purification units of the present invention connected in series;

[0033] Figure 2 This is a schematic diagram of the parallel connection of the filtration and purification units of the present invention;

[0034] Figure 3 This is a schematic diagram of the parallel connection of the booster units of the present invention. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and 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 this invention.

[0038] like Figure 1-3As shown, a negative pressure sampling system for coke oven gas pipeline includes a coke oven gas main pipeline 1 and a sampling main pipe connected to the coke oven gas main pipeline 1. The pipe wall of the coke oven gas main pipeline 1 is provided with a heat insulation layer. A sampling head unit 2 is connected to the sampling main pipe. The sampling head unit 2 includes a valve 3 and an anti-clogging sampling head 4 arranged in series on the sampling main pipe.

[0039] The sampling head unit 2 is connected in series with the pressurization unit 5 (two sets of pressurization units 5 are set in parallel, and valves are installed on the parallel pipeline, one for backup and one for use). The air inlet of the pressurization unit 5 is connected to the end of the sampling main pipe away from the anti-blocking sampling head 4. One-way valves 6 are installed at the air inlet and air outlet of the pressurization unit 5 respectively.

[0040] The pressurization unit 4 is connected in series with the filtration and purification unit 7, and the filtration and purification unit 7 is connected in series with the flow regulation unit 8. The flow regulation unit 8 detects the sampled flow rate in real time and feeds it back to the controller 9. The controller 9 adjusts the opening of the flow regulation valve to stabilize the sampled flow rate within a preset range.

[0041] The sampling main pipe is equipped with an anti-clogging sampling head at one end. The anti-clogging sampling head is connected to a pipe that extends into the coke oven gas pipeline. The sampling main pipe wall is equipped with an insulation layer to prevent tar in the gas from condensing and clogging the pipeline, and also to prevent tar from condensing and adhering to the anti-clogging sampling head. The anti-clogging sampling head is equipped with a porous sand core filter device with a polytetrafluoroethylene (PTFE) anti-stick filter membrane on its surface, which ensures gas flow while blocking large particulate impurities.

[0042] In a further preferred embodiment of the present invention, the anti-clogging sampling head 4 is configured as a porous sand core filter structure, and the surface is provided with a polytetrafluoroethylene anti-sticking filter membrane.

[0043] In the above embodiments, the anti-clogging sampling head uses a porous sand core filter with a polytetrafluoroethylene (PTFE) anti-sticking filter membrane on its surface. This ensures gas flow while blocking large particulate impurities, effectively preventing tar and impurities from adhering, avoiding pipeline blockage, and extending the service life of the equipment.

[0044] In a further preferred embodiment of the present invention, the booster unit 5 includes a booster pump 10 and a pressure sensor 11 connected in series with the booster pump 10;

[0045] The booster pump 10 is a miniature oil-free booster pump, with its input end connected to the end of the sampling main pipe away from the anti-clogging sampling head.

[0046] In the above embodiments, one-way valves are provided at both the inlet and outlet of the booster pump to prevent gas backflow; the controller adjusts the output power of the booster pump according to the pressure sensor detection value of the sampling main pipe to maintain the pressure in the sampling pipeline at 0.02-0.1MPa, effectively balancing the negative pressure environment of the coke oven gas pipeline and ensuring smooth gas output.

[0047] In a further preferred embodiment of the present invention, the booster unit 5 is electrically connected to the controller 9, which is a PLC controller. The controller 9 adjusts the output power of the booster pump according to the pressure sensor detection value of the sampling main pipe.

[0048] The PLC controller is electrically connected to the valves on the pipeline.

[0049] In the above embodiments, the pressure in the sampling pipeline is maintained at 0.02-0.1MPa by the PLC controller, which effectively balances the negative pressure environment of the coke oven gas pipeline and ensures that the gas is smoothly discharged.

[0050] In a further preferred embodiment of the present invention, the filtration and purification unit 7 includes a first filter component 12 and a second filter component 13 connected in series.

[0051] The filtration and purification unit 7 is configured in one or two sets connected in series with the pressurization unit 5. When the filtration and purification units 7 are connected in parallel, control valves are connected to them.

[0052] The first filter component 12 is a dust filter component, which is a tar and dust filter equipped with a glass fiber filter membrane, with a filtration accuracy ≥0.24μm;

[0053] The second filter element 13 is a precision filter element, which uses a polytetrafluoroethylene filter membrane with a filtration accuracy of 0.1-0.3μm.

[0054] In the above embodiments, the dust filtration component has a filtration accuracy of ≥0.24μm, removing and adsorbing tar mist and dust particles in the coal gas; the precision filtration component uses a polytetrafluoroethylene filter membrane with a filtration accuracy of 0.1-0.3μm, further removing fine impurities and residual tar to ensure sample purity.

[0055] In a further preferred embodiment of the present invention, the outlet end of the flow regulating unit 8 is connected to the sampling storage unit 14, and the sampling storage unit 14 includes a sample receiver or absorption device, the input end of the sample receiver or absorption device being connected to the output end of the flow regulating unit.

[0056] The sample receiver or absorption device uses an aluminum foil composite film and a polypropylene (PP) dual-valve gas sampling bag.

[0057] The sample receiver or absorption device input is connected to the output of the flow regulation unit, and the collected sample can be directly brought into the laboratory for analysis.

[0058] The sampling and storage unit can be a sample absorption system, which uses different absorbents depending on the detection requirements of different gas components. Specific Implementation Example 1:

[0060] A method for negative pressure sampling of coke oven gas pipelines based on a coke oven gas pipeline negative pressure sampling system includes the following steps;

[0061] S1 System Pretreatment: Prepare a gas absorption device or system in advance. The absorption device or system mainly consists of an aluminum foil composite film and a polypropylene (PP) dual-valve gas sampling bag. The air in the sampling bag is discharged by multiple compressions; or a vacuum pump is used to vacuum the sampling bag to reduce resistance during the sampling process.

[0062] S2 Pressure Pre-regulation: The controller uses the pressure sensor on the sampling main pipe and activates the booster unit, adjusting its output power to bring the pressure in the sampling main pipe to a preset equilibrium pressure value of 0.02-0.1 MPa. When the absolute value of the negative pressure in the pipeline is ≥0.05 MPa, the equilibrium pressure value is set to 0.05-0.1 MPa; when the absolute value of the negative pressure in the pipeline is <0.05 MPa, the equilibrium pressure value is set to 0.02-0.05 MPa, ensuring pressure balance.

[0063] S3 Sampling Flow Rate Adjustment: Open the flow rate adjustment valve, and the controller adjusts the valve opening according to the flow meter detection value to stabilize the sampling flow rate at the gas flow rate specified in the standard, ensuring a uniform sampling rate;

[0064] S4 staged sampling: First, open the valve on the sampling pipeline and allow the gas flow to pass through the sampling main pipe, pressurization unit, filtration and purification unit, and flow regulation unit for 5-10 minutes to flush the pipeline and remove air and residual impurities. Then, connect the gas sampling and absorption device for sampling. During the sampling process, the gas pressure and flow rate can be monitored in real time through pressure sensors and flow meters. When the pressure fluctuation exceeds ±0.01MPa or the flow fluctuation exceeds ±10mL / min, the power of the pressurization unit and the opening of the flow regulation valve can be adjusted to maintain sampling stability. When the sampling volume meets the detection requirements or reaches the maximum volume of the sampling bag, the controller closes the flow regulation valve and the pressurization unit.

[0065] S5 Sample Sealing: After sampling, close the inlet and outlet valves of the sampling bag to complete sample sealing, and subsequent sample component analysis can be carried out.

[0066] The method for negative pressure sampling of coke oven gas pipelines using the above system includes the following steps:

[0067] Sample collection tools: Three 2L aluminum foil composite film + polypropylene PP double valve gas sampling bags (one spare), check valve sealing to ensure no damage or leakage; equipped with one small portable vacuum pump and several rubber connecting tubes.

[0068] Pretreatment procedure: Connect the sampling bag to the vacuum pump, turn on the pump to evacuate the sampling bag, close the valve and let it stand for 30 seconds, observe whether the pressure rises (a rise of ≤0.005MPa is acceptable); repeat the vacuuming-evacuation operation 3 times to completely remove residual air in the bag and reduce sampling interference;

[0069] Connecting the pipeline: Connect the gas pipeline outlet to the anti-clogging sampling head, booster pump, pressure sensor, filter purification unit, and wet gas flow meter in sequence through a rubber hose to form the main sampling pipeline. Ensure that each interface is firmly fixed with clamps and there is no gas leakage.

[0070] Sampling flow rate adjustment: Open the gas pipeline valve, start the booster pump and adjust the valve opening through the pressure sensor to stabilize the sampling gas flow rate at the gas flow rate specified in the standard, and ensure uniform sampling rate.

[0071] Pipeline flushing: Keep the gas pipeline, booster pump, and flow regulating valve open, allowing the gas to flow through the main pipeline and each unit to flush away residual air and impurities from the inner wall of the pipeline, for about 5-10 minutes.

[0072] The gas sampling bag is connected for sampling. During the sampling process, the gas pressure and flow rate can be monitored in real time through pressure sensor and flow meter data. When the pressure fluctuation exceeds ±0.01MPa or the flow rate fluctuation exceeds ±10mL / min, the power of the booster unit and the opening of the flow regulating valve can be adjusted to maintain sampling stability. When the sampling volume meets the detection requirements or reaches the maximum volume of the sampling bag, the controller closes the flow regulating valve and the booster unit.

[0073] Termination of sampling: When the volume of the sampling bag reaches 1.8L (close to the maximum volume of 2L, which meets the testing requirements), turn off the flow regulating valve and the booster pump, close the gas pipeline valve, and stop sampling;

[0074] First close the inlet valve of the sampling bag, then close the outlet valve to ensure a double seal and no leakage;

[0075] Mark the sampling information on the surface of the sampling bag with a marker: sample name, sampling date, sampling time, sampling flow rate or velocity, etc. Place the sample upright in a cool, dry place in the laboratory for subsequent component analysis. Specific Implementation Example 2:

[0077] An application of a negative pressure sampling method for coke oven gas pipelines based on a negative pressure sampling system for coke oven gas pipelines is characterized by: applying the negative pressure sampling method to coke oven gas pipeline sampling to solve the problems of difficult sampling, unstable flow, and easy contamination of samples under negative pressure conditions, thereby achieving efficient and accurate sampling.

[0078] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0079] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A negative pressure sampling system for coke oven gas pipelines, comprising a main coke oven gas pipeline (1) and a sampling main pipe connected to the main coke oven gas pipeline (1), characterized in that: The main pipe of the coke oven gas (1) has a heat insulation layer on its pipe wall. The sampling head unit (2) is connected to the sampling main pipe. The sampling head unit (2) includes a valve (3) and an anti-blocking sampling head (4) connected in series on the sampling main pipe. The sampling head unit (2) is connected in series with the boosting unit (5). The air inlet of the boosting unit (5) is connected to the end of the sampling main pipe (1) away from the anti-blocking sampling head (4). One-way valves (6) are installed at the air inlet and air outlet of the boosting unit (5). The pressurization unit (5) is connected in series with the filtration and purification unit (7), and the filtration and purification unit (7) is connected in series with the flow regulation unit (8). The flow regulation unit (8) detects the sampled flow rate in real time and feeds it back to the controller (9). The controller (9) adjusts the opening of the flow regulation valve to stabilize the sampled flow rate within the preset range.

2. The negative pressure sampling system for coke oven gas pipelines according to claim 1, characterized in that: The anti-clogging sampling head (4) is configured as a porous sand core filter structure, and the surface is provided with a polytetrafluoroethylene anti-sticking filter membrane.

3. The negative pressure sampling system for coke oven gas pipelines according to claim 2, characterized in that: The booster unit (5) includes a booster pump (10) and a pressure sensor (11) connected in series with the booster pump (10). The booster pump (10) is a miniature oil-free booster pump, with its input end connected to the end of the sampling main pipe away from the anti-clogging sampling head.

4. The negative pressure sampling system for coke oven gas pipelines according to claim 3, characterized in that: The booster unit (5) is electrically connected to the controller (9), which is a PLC controller. The controller (9) adjusts the output power of the booster pump according to the pressure sensor detection value of the sampling main pipe, so that the pressure in the sampling pipeline is maintained at 0.02-0.1MPa, effectively balancing the negative pressure environment of the coke oven gas pipeline and ensuring that the gas is smoothly discharged.

5. The negative pressure sampling system for coke oven gas pipelines according to claim 4, characterized in that: The filtration and purification unit (7) includes a first filter component (12) and a second filter component (13) connected in series. The filtration and purification unit (7) is configured to be connected in series with the pressurization unit (5) in one or two sets.

6. The negative pressure sampling system for coke oven gas pipelines according to claim 5, characterized in that: The first filter component (12) is a dust filter component. The dust filter component adopts a tar and dust filter equipped with a glass fiber filter membrane, and the filtration accuracy is ≥0.24μm. The second filter component (13) is a precision filter component. The precision filter component uses a polytetrafluoroethylene filter membrane with a filtration accuracy of 0.1-0.3μm.

7. The negative pressure sampling system for coke oven gas pipelines according to claim 6, characterized in that: The outlet end of the flow regulating unit (8) is connected to the sampling storage unit (14), which includes a sample receiver or absorption device. The input end of the sample receiver or absorption device is connected to the output end of the flow regulating unit (8). The sample receiver or absorption device uses an aluminum foil composite film and a polypropylene (PP) dual-valve gas sampling bag.

8. A method for negative pressure sampling of coke oven gas pipelines based on a coke oven gas pipeline negative pressure sampling system, characterized in that: Includes the following steps; S1 system pretreatment: Prepare a gas absorption device or system in advance. The absorption device or system mainly consists of an aluminum foil composite film and a polypropylene (PP) dual-valve gas sampling bag. The air in the sampling bag is discharged by squeezing it multiple times or a vacuum pump is used to vacuum the sampling bag to reduce the resistance during the sampling process. S2 Pressure Pre-regulation: The controller uses the pressure sensor on the sampling main pipe and activates the booster unit, adjusting its output power to bring the pressure in the sampling main pipe to a preset equilibrium pressure value of 0.02-0.1 MPa. When the absolute value of the negative pressure in the pipeline is ≥0.05 MPa, the equilibrium pressure value is set to 0.05-0.1 MPa; when the absolute value of the negative pressure in the pipeline is <0.05 MPa, the equilibrium pressure value is set to 0.02-0.05 MPa, ensuring pressure balance. S3 Sampling Flow Rate Adjustment: Open the flow rate adjustment valve, and the controller adjusts the valve opening according to the flow meter detection value to stabilize the sampling flow rate at the gas flow rate specified in the standard, ensuring a uniform sampling rate; S4 staged sampling: First, open the valve on the sampling pipeline and allow the gas flow to pass through the sampling main pipe, pressurization unit, filtration and purification unit, and flow regulation unit for 5-10 minutes to flush the pipeline and remove air and residual impurities. Then, connect the gas sampling and absorption device for sampling. During the sampling process, the gas pressure and flow rate can be monitored in real time through pressure sensors and flow meters. When the pressure fluctuation exceeds ±0.01MPa or the flow fluctuation exceeds ±10mL / min, the power of the pressurization unit and the opening of the flow regulation valve can be adjusted to maintain sampling stability. When the sampling volume meets the detection requirements or reaches the maximum volume of the sampling bag, the controller closes the flow regulation valve and the pressurization unit. S5 Sample Sealing: After sampling, close the inlet and outlet valves of the sampling bag to complete sample sealing, and subsequent sample component analysis can be carried out.

9. An application of a negative pressure sampling method for coke oven gas pipelines based on a negative pressure sampling system for coke oven gas pipelines, characterized in that: Applying the negative pressure sampling method for coke oven gas pipelines solves the problems of difficult sampling, unstable flow, and easy contamination of samples under negative pressure conditions, thus achieving efficient and accurate sampling.

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