A multi-stage pressure stabilizing pretreatment system for coal gas recovery sampling

Abstract

The embodiment of the present application provides a multistage pressure stabilizing pretreatment system for coal gas recovery sampling, and relates to the technical field of blast furnace coal gas recycling. The multistage pressure stabilizing pretreatment system for coal gas recovery sampling comprises an initial coal gas conveying pipe, a primary pressure stabilizing component, a water washing component and a secondary pressure stabilizing component, the primary pressure stabilizing component is communicated with the initial coal gas conveying pipe, the water washing component is communicated with the primary pressure stabilizing component, and the secondary pressure stabilizing component is communicated with the water washing component. The multistage pressure stabilizing pretreatment system can remove impurities from the original coal gas for multiple times and stabilize the pressure for multiple times, the coal gas can be kept clean and the pressure can be stable when the analytical instrument samples the coal gas, so that the analytical instrument is protected, the failure rate of the analytical instrument is reduced, and the service life of the analytical instrument can be prolonged.

Description

Technical Field

[0001] This invention relates to the field of blast furnace gas recovery and utilization, and more specifically, to a multi-stage pressure stabilization pretreatment system for gas recovery sampling. Background Technology

[0002] The blast furnace ironmaking process generates a large amount of blast furnace gas, which can be used for combustion in hot blast stoves. Simultaneously, coke oven gas and converter gas are added to the hot blast stove combustion, burning together with the blast furnace gas. Different gases have different compositions, therefore, it is necessary to analyze the composition of each gas to adjust the supply ratio according to production needs.

[0003] Because the pressure of coal gas is unstable during transportation, and the coal gas itself contains a lot of impurities (tar, naphthalene, dust, etc.), the sampling probe filter element is easily blocked by impurities during sampling. Moreover, the unstable coal gas pressure will damage the analytical instrument, resulting in a large amount of maintenance work for the analytical instrument and a short service life. Summary of the Invention

[0004] This invention provides a multi-stage pressure-stabilizing pretreatment system for coal gas recovery and sampling, which can solve the above-mentioned problems.

[0005] The embodiments of the present invention can be implemented as follows: Embodiments of the present invention provide a multi-stage pressure stabilization pretreatment system for coal gas recovery sampling, comprising: Initial gas delivery pipe, used to deliver raw gas; The primary pressure stabilizing component is connected to the initial gas delivery pipe and is used for preliminary impurity removal and primary pressure stabilization of the raw gas. The water washing component is connected to the primary pressure stabilizing component and is used to wash and remove impurities from the impurity-containing coal gas output from the primary pressure stabilizing component. The secondary pressure stabilizing component is connected to the water washing component and is used to perform secondary pressure stabilization on the clean gas output from the water washing component.

[0006] Optionally, the primary pressure stabilizing component includes a primary external water stabilizing tank. The primary external water stabilizing tank is provided with a first air inlet, a first air outlet, and a first vent. The first air inlet is connected to the initial gas delivery pipe, the first air outlet is connected to the water washing component, and the first vent is used to regulate and stabilize the gas in the primary external water stabilizing tank.

[0007] Optionally, the primary external water stabilization tank is also equipped with a first overflow port and a drain port, with a drain valve installed at the drain port.

[0008] Optionally, the secondary voltage stabilizing component includes a two-stage segmented water stabilizing tank, which is provided with a second vent, a third vent, and a second overflow port, and is connected to the water washing component.

[0009] Optionally, the water washing assembly includes a water washing tank, a water cooler, and a first water filter, wherein the first water filter, the water cooler, and the water washing tank are connected in sequence.

[0010] Optionally, the multi-stage pressure-stabilizing pretreatment system also includes a dehumidifier, which is located after the output end of the water washing tank and is also connected to the secondary segmented water stabilizing tank.

[0011] Optionally, the multi-stage pressure-stabilizing pretreatment system also includes a filter, which is located after the output end of the water washing tank and is used to separate water and gas in the clean coal gas output from the water washing tank.

[0012] Optionally, the filter includes a primary filter and a secondary filter. The primary filter is located between the water washing tank and the dehumidifier, and the secondary filter is located after the output end of the dehumidifier. The primary filter is also connected to the secondary segmented water stabilization tank.

[0013] Optionally, the multi-stage pressure-stabilizing pretreatment system also includes an ejector assembly for pressurizing and diverting the impurity-laden gas output from the primary pressure-stabilizing assembly.

[0014] Optionally, the ejector assembly includes an ejector and a gas-liquid separator. The impurity-containing coal gas output from the primary pressure stabilizing assembly enters the ejector and is guided by pressurized water flow. The gas-liquid separator is located at the rear end of the ejector.

[0015] Beneficial effects of the embodiments of the present invention: This multi-stage pressure-stabilizing pretreatment system for coal gas recovery and sampling includes an initial coal gas delivery pipe, a primary pressure-stabilizing component, a water washing component, and a secondary pressure-stabilizing component. The primary pressure-stabilizing component is connected to the initial coal gas delivery pipe, which supplies raw coal gas to the primary pressure-stabilizing component. The primary pressure-stabilizing component performs preliminary impurity removal and primary pressure stabilization on the supplied raw coal gas. The water washing component is connected to the primary pressure-stabilizing component, which performs a second water washing and impurity removal on the impurity-laden coal gas output from the primary pressure-stabilizing component, removing impurities such as tar and naphthalene. The secondary pressure-stabilizing component is connected to the water washing component, which performs a second pressure stabilization on the clean coal gas output from the water washing component, maintaining a stable pressure for the clean coal gas, facilitating sampling and analysis by various analytical instruments. This multi-stage pressure-stabilizing pretreatment system, by performing multiple impurity removals and multiple pressure adjustments on the raw coal gas containing impurities, ensures that the coal gas remains clean and its pressure is stable during sampling by analytical instruments, thereby protecting the analytical instruments, reducing their failure rate, and extending their service life. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a multi-stage pressure stabilization pretreatment system for coal gas recovery sampling provided in an embodiment of the present invention.

[0018] Icons: 1-Primary pressure stabilizing component; 10-First-stage external water stabilizing tank; 101-First vent; 102-First overflow port; 103-Drain valve; 2-Secondary pressure stabilizing component; 20-Second-stage segmented water stabilizing tank; 201-Second overflow port; 202-Second vent; 203-Third vent; 3-Water washing component; 30-Water washing tank; 301-Side overflow port; 31-Water cooler; 32-First water filter; 33-Flow meter; 34-First needle valve; 4-Ejector component; 40-Ejector; 41-Second water filter; 42-Pressure reducing valve; 43-Gas-water separator; 44-Inlet valve; 45-Pressure gauge; 46-Second needle valve; 5-First-stage filter; 6-Second-stage filter; 7-Dehumidifier. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0021] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0022] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, 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, and therefore should not be construed as a limitation of this invention.

[0023] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0024] The terms “comprising,” “including,” or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0025] Unless otherwise explicitly specified and limited, terms such as "setup" and "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0026] It should be noted that, for the sake of simplicity, the aforementioned method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to this application, some steps can be performed in other orders or simultaneously. The steps in the methods of this application embodiments can be adjusted, combined, or deleted according to actual needs.

[0027] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0028] The blast furnace ironmaking process generates a large amount of blast furnace gas. Besides the gas used in the hot blast stove and the furnace top area, excess blast furnace gas is centrally managed in a gas holder after gravity dust removal. The hot blast stove mainly uses blast furnace gas, coke oven gas, and converter gas for combustion. Different types of gas have different compositions, and the delivery ratio of each type needs to be adjusted according to production conditions; therefore, compositional analysis of each type of gas is necessary.

[0029] Coal gas has a complex composition, typically containing a significant amount of impurities such as tar, naphthalene, and dust, which can lead to issues with transmission pressure. Currently, the method for detecting coal gas composition involves inserting a sampling probe into the pipeline transporting the coal gas to collect samples for analysis. However, the inventors discovered that this method has significant drawbacks: due to the large number of impurities in the coal gas, these impurities easily clog the filter element of the sampling probe, and unstable coal gas pressure can damage the analytical instruments, resulting in frequent maintenance and replacement, and a short service life.

[0030] In view of this, embodiments of the present invention provide a multi-stage pressure stabilization pretreatment system for coal gas recovery and sampling. This system can solve the above problems, realize the removal of impurities and pressure regulation of coal gas, and ensure that the coal gas is clean and the pressure is stable when the analytical instrument samples the coal gas. The following will describe it in detail.

[0031] Please refer to Figure 1 The multi-stage pressure stabilization pretreatment system for coal gas recovery and sampling includes an initial coal gas delivery pipe, a primary pressure stabilization component 1, a water washing component 3, and a secondary pressure stabilization component 2. The primary pressure stabilization component 1 is connected to the initial coal gas delivery pipe, which delivers raw coal gas to the primary pressure stabilization component 1. The primary pressure stabilization component 1 performs preliminary impurity removal and first pressure regulation on the delivered raw coal gas. The water washing component 3 is connected to the primary pressure stabilization component 1, which performs a second water washing to remove impurities such as tar and naphthalene from the coal gas output from the primary pressure stabilization component 1. The secondary pressure stabilization component 2 is connected to the water washing component 3, which performs a second pressure regulation on the clean coal gas output from the water washing component 3, so that the pressure of the clean coal gas delivered to the analytical instruments remains stable and that the pressure of the clean coal gas is within the measurement range of the analytical instruments, facilitating sampling and analysis by various analytical instruments.

[0032] The multi-stage pressure stabilization pretreatment system in this embodiment is equipped with a primary pressure stabilization component 1 and a secondary pressure stabilization component 2. The primary pressure stabilization component 1 and the secondary pressure stabilization component 2 perform multiple pressure adjustments and stabilizations on the coal gas to keep the pressure of the coal gas stable. At the same time, the primary pressure stabilization component 1 and the water washing component 3 remove impurities from the coal gas multiple times. When the analyzer samples the coal gas, the coal gas can remain clean and the pressure is stable, avoiding impurities from clogging the sampling filter of the analyzer and preventing impurities from adhering to the inside of the analyzer or the cooler, thereby protecting the analyzer and improving its service life.

[0033] The impure gas output from the primary pressure stabilizing component 1 may have insufficient pressure. Therefore, an ejector component 4 is provided between the primary pressure stabilizing component 1 and the water washing component 3 to increase the conveying speed of the impure gas. In this embodiment, the ejector component 4 adopts a water ejection method and includes an ejector 40, a second water filter 41, a pressure reducing valve 42, a gas-water separator 43, an inlet valve 44, a pressure gauge 45, and a second needle valve 46.

[0034] The ejector 40 is connected to a water inlet pipe. A second water filter 41 and a pressure reducing valve 42 are sequentially installed on the water inlet pipe. The second water filter 41 is used to filter out impurities such as mud and sand in the water inlet. The pressure reducing valve 42 is used to appropriately reduce the pressure of the high-pressure water inlet. After the high-pressure water is reduced, it mixes with the impure coal gas entering the ejector 40, causing the impure coal gas to flow rapidly. A second needle valve 46 is installed on the pipe between the pressure reducing valve 42 and the ejector 40. A pressure gauge 45 is connected to the second needle valve 46. The pressure gauge 45 detects the water pressure after pressure reduction to ensure that the water pressure meets the design requirements.

[0035] The water outlet of ejector 40 is connected to gas-water separator 43 via a pipe. Impure coal gas and water flow into gas-water separator 43 for water-gas separation. Impure coal gas is mixed between ejector 40 and gas-water separator 43, thereby dissolving and removing some impurities in the impure coal gas. The water separated in gas-water separator 43 is guided to primary pressure stabilizing component 1 through a pipe. Since the coal gas separated from gas-water separator 43 still contains impurities, further impurity removal is required. Therefore, the coal gas separated from gas-water separator 43 enters water washing component 3 for further impurity removal.

[0036] Continue to refer to Figure 1 The primary pressure stabilizing component 1 includes a primary external water stabilizing tank 10, which has a first air inlet and a first air outlet at its top. One end of the initial gas delivery pipe extends into the primary external water stabilizing tank 10 through the first air inlet. The water separated in the gas-water separator 43 is guided into the primary external water stabilizing tank 10. The end of the initial gas delivery pipe is submerged in the water of the primary external water stabilizing tank 10. The raw gas delivered by the initial gas delivery pipe first enters the water of the primary external water stabilizing tank 10. The water adsorbs and removes impurities such as tar and dust from the raw gas, thus achieving the first impurity removal of the raw gas. The other end of the initial gas delivery pipe extends into the main gas pipeline, and the gas is collected through the initial gas delivery pipe. The first gas outlet is connected to the gas inlet of the ejector 40 through a pipe. The primary external water stabilization tank 10 removes impurities from the original coal gas, turning it into impure coal gas. The impure coal gas enters the ejector 40 through the pipe from the first gas outlet, where it undergoes a second impurity removal process. An air inlet valve 44 is installed on the pipe connecting the first gas outlet to the gas inlet of the ejector 40, which controls the intake or disconnection of the gas.

[0037] The side wall of the primary external water stabilization tank 10 is provided with a first overflow port 102. When there is too much water in the tank, it can overflow through the first overflow port 102, thereby ensuring that the water level in the primary external water stabilization tank 10 remains unchanged.

[0038] The top of the primary external water stabilizer tank 10 is also provided with a first vent 101. When the gas pressure inside the tank is greater than the water seal pressure, the gas can be released through the first vent 101 to prevent excessive pressure and to regulate and stabilize the gas inside the primary external water stabilizer tank 10. The primary external water stabilizer tank 10 is provided with a water inlet pipe. The upper end of the water inlet pipe is in close contact with the top of the primary external water stabilizer tank 10, and the lower end of the water inlet pipe is left with a gap from the bottom of the primary external water stabilizer tank 10. The size of the gap between the lower end of the water inlet pipe and the bottom of the primary external water stabilizer tank 10 can be customized. The height between the lower end of the water inlet pipe and the first overflow port 102 is the water seal height, and the water seal pressure refers to the pressure generated by the water seal height.

[0039] The bottom of the primary external water stabilization tank 10 is also equipped with a drain port, which is connected to a drain pipe. A drain valve 103 is installed on the drain pipe. Manual draining and cleaning of the primary external water stabilization tank 10 can be achieved by opening or closing the drain valve 103.

[0040] The gas separated from the gas-water separator 43 still needs further impurity removal. A water washing assembly 3 is installed at the rear end of the gas-water separator 43 to remove impurities from the gas after the second impurity removal.

[0041] refer to Figure 1 The water washing assembly 3 includes a water washing tank 30, a water cooler 31, a flow meter 33, a first needle valve 34, and a first water filter 32. The water washing tank 30 has an inlet pipe connected to its inlet end. The first water filter 32, the first needle valve 34, the flow meter 33, and the water cooler 31 are sequentially installed on this pipe from the direction of water flow. The first water filter 32 filters out impurities such as mud, sand, and plastic debris from the water flow. The flow meter 33 is connected to the first needle valve 34 and detects the water flow rate. The water cooler 31 cools the clean water flow and then outputs the low-temperature clean water into the water washing tank 30. Because the coal gas contains impurities such as naphthalene and oil, room temperature water cannot effectively dissolve and adsorb these impurities. Therefore, low-temperature clean water is used to further remove these impurities.

[0042] The gas outlet of the gas-water separator 43 is connected to the water washing tank 30 through a pipe. One end of the pipe is connected to the gas outlet of the gas-water separator 43, and the other end is submerged below the surface of the low-temperature clean water inside the water washing tank 30. The low-temperature clean water is used to remove impurities from the coal gas for the third time. The low-temperature clean water can cool down the naphthalene and oil impurities in the coal gas, causing these impurities to liquefy into droplets, which are then retained inside the water washing tank 30.

[0043] The side wall of the washing tank 30 is provided with a side overflow port 301, which is connected to the secondary pressure stabilizing component 2 through a pipe. The secondary pressure stabilizing component 2 includes a secondary segmented water stabilizing tank 20. The water inside the secondary segmented water stabilizing tank 20 is collected by the overflow of the washing tank 30, that is, all the water overflowing from the side overflow port 301 enters the secondary segmented water stabilizing tank 20.

[0044] The top of the secondary-stage water-stabilized tank 20 is provided with a second vent 202 and a third vent 203, which are located at different heights of the secondary-stage water-stabilized tank 20. The second vent 202 and the third vent 203 are used to stabilize the pressure of the washed gas. Specifically, the secondary-stage water-stabilized tank 20 has a stepped top. A vertical water inlet pipe is installed inside the secondary-stage water-stabilized tank 20. The bottom end of the vertical water inlet pipe is spaced from the bottom surface of the secondary-stage water-stabilized tank 20, and the top end of the vertical water inlet pipe is connected to the top of the stepped section of the secondary-stage water-stabilized tank 20. The second vent 202 is located on the lower step of the top, and the third vent 203 is located on the higher step of the top. Simultaneously, a second overflow port 201 is also provided on the side wall of the secondary-stage water-stabilized tank 20, located near the second vent 202.

[0045] The outlet of the water washing pipe is connected to the primary filter 5 via a pipeline. The primary filter 5 is used to further filter impurities from the water-washed gas. The primary filter 5 can be a 50μm coarse filter to perform a fourth impurity removal on the water-washed gas. The drain outlet of the primary filter 5 is connected to the secondary segmented water stabilization tank 20 via a pipeline, thereby achieving pressure stabilization of the water-washed gas.

[0046] The gas filtered by the primary filter 5 still contains moisture. Therefore, a dehumidifier 7 is installed after the primary filter 5. The inlet of the dehumidifier 7 is connected to the outlet of the primary filter 5, and the outlet of the dehumidifier 7 is connected to the secondary segmented water stabilization tank 20. The water generated after dehumidifying the gas is discharged into the secondary segmented water stabilization tank 20 to achieve pressure stabilization. The outlet of the dehumidifier 7 is connected to the secondary filter 6, which performs a fifth impurity removal on the dehumidified gas. The secondary filter 6 can be a 10μm fine filter. The gas passing through the secondary filter 6 contains virtually no or very few impurities, and can then be used as a sample gas for gas analysis instruments. Of course, more filters can be added after the secondary filter 6.

[0047] Since the secondary segmented water stabilization tank 20 is equipped with a vertical water inlet pipe, a second vent 202 and a third vent 203, and the primary filter 5 and dehumidifier 7 are connected to the secondary segmented water stabilization tank 20, the secondary segmented water stabilization tank 20 can reduce and stabilize the gas pressure, ensuring the stability of the gas pressure when the gas analysis instrument takes samples.

[0048] The multi-stage pressure-stabilizing pretreatment system for coal gas recovery and sampling in this invention removes impurities from the coal gas multiple times to prevent them from entering the coal gas analyzer. Simultaneously, it regulates and stabilizes the pressure of the coal gas to ensure that the gas pressure remains stable and within the measurement range of the analyzer during sampling. This system can pretreat various types of difficult-to-process coal gas, enabling the coal gas analyzer to sample and analyze it, protecting the analyzer and extending its service life.

[0049] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A multi-stage pressure-stabilizing pretreatment system for coal gas recovery and sampling, characterized in that, include: An initial gas delivery pipe, wherein the initial gas delivery pipe is used to deliver raw gas; Primary pressure stabilizing component (1), which is connected to the initial gas delivery pipe, is used to perform preliminary impurity removal and primary pressure stabilization on the raw gas; Water washing assembly (3), which is connected to the primary pressure stabilizing assembly (1), is used to wash and remove impurities from the impurity-containing coal gas output from the primary pressure stabilizing assembly (1). Secondary pressure stabilizing component (2), which is connected to the water washing component (3), is used to perform secondary pressure stabilization on the clean coal gas output by the water washing component (3).

2. The multi-stage pressure stabilization pretreatment system for gas recovery sampling according to claim 1, characterized in that, The primary pressure stabilizing component (1) includes a primary external water stabilizing tank (10). The primary external water stabilizing tank (10) is provided with a first air inlet, a first air outlet and a first vent (101). The first air inlet is connected to the initial gas delivery pipe, the first air outlet is connected to the water washing component (3), and the first vent (101) is used to regulate and stabilize the gas in the primary external water stabilizing tank (10).

3. The multi-stage pressure-stabilizing pretreatment system for gas recovery sampling according to claim 2, characterized in that, The primary external water stabilization tank (10) is also provided with a first overflow port (102) and a drain port, and the drain port is equipped with a drain valve (103).

4. The multi-stage pressure stabilization pretreatment system for gas recovery sampling according to claim 1, characterized in that, The secondary pressure stabilizing component (2) includes a secondary segmented water stabilizing tank (20), which is provided with a second vent (202), a third vent (203) and a second overflow port (201). The secondary segmented water stabilizing tank (20) is connected to the water washing component (3).

5. The multi-stage pressure stabilization pretreatment system for gas recovery sampling according to claim 4, characterized in that, The water washing assembly (3) includes a water washing tank (30), a water cooler (31), and a first water filter (32), wherein the first water filter (32), the water cooler (31), and the water washing tank (30) are connected in sequence.

6. The multi-stage pressure-stabilizing pretreatment system for gas recovery sampling according to claim 5, characterized in that, The multi-stage pressure stabilization pretreatment system also includes a dehumidifier (7), which is located behind the output end of the water washing tank (30) and is also connected to the secondary segmented water stabilization tank (20).

7. The multi-stage pressure stabilization pretreatment system for gas recovery sampling according to claim 6, characterized in that, The multi-stage pressure stabilization pretreatment system also includes a filter, which is located behind the output end of the water washing tank (30) and is used to separate water and gas in the clean coal gas output from the water washing tank (30).

8. The multi-stage pressure-stabilizing pretreatment system for gas recovery sampling according to claim 7, characterized in that, The filter includes a primary filter (5) and a secondary filter (6). The primary filter (5) is located between the water washing tank (30) and the dehumidifier (7). The secondary filter (6) is located behind the output end of the dehumidifier (7). The primary filter (5) is also connected to the secondary segmented water stabilization tank (20).

9. The multi-stage pressure-stabilizing pretreatment system for gas recovery sampling according to any one of claims 1-8, characterized in that, The multi-stage pressure stabilization pretreatment system also includes an ejector assembly (4), which is used to pressurize and guide the impurity-containing coal gas output from the primary pressure stabilization assembly (1).

10. The multi-stage pressure-stabilizing pretreatment system for gas recovery sampling according to claim 9, characterized in that, The ejector assembly (4) includes an ejector (40) and a gas-water separator (43). The impure coal gas output from the primary pressure stabilizing assembly (1) enters the ejector (40) and is guided by pressurized water flow. The gas-water separator (43) is located at the rear end of the ejector (40).

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