Gas filtering device and method for coal bed gas exploitation

Abstract

The invention relates to the technical field of purification devices, in particular to a gas filtering device and method for coalbed methane exploiting.The device comprises a main pipe, the main pipe is provided with a filtering assembly, a drying assembly, a compressor and an injection assembly, the outlet end of the injection assembly is connected with a first pipe body, the first pipe body communicates with a second pipe body, and the second pipe body communicates with a conical bin; the top of the conical bin is connected with an air outlet pipe; a backflow opening is formed in the conical bin, the backflow opening is communicated to a side suction opening of the spraying assembly, the first pipe body and the second pipe body are communicated and form a U-shaped structure, and amine liquid is injected into the first pipe body and the second pipe body; when gas is guided into the first pipe body through the injection assembly, gas lift is formed, amine liquid in the pipe is pushed and lifted into the conical bin and falls back into the pipe body to be mixed again after being mixed with the gas, the gas lift is circulated in a reciprocating mode, and the gas-liquid contact area is increased; by arranging the conical bin and dynamically controlling and buffering the liquid level of the inner ring channel, the amine liquid is prevented from being brought into the gas outlet when the gas flow fluctuates, and the gas-liquid contact area and the interface updating frequency are increased.

Description

Technical Field

[0001] This invention relates to the field of purification equipment technology, specifically to a gas filtration device and method for coalbed methane extraction. Background Technology

[0002] In coalbed methane production well sites, the raw coalbed methane extracted typically contains a high proportion of methane, along with carbon dioxide, nitrogen, hydrogen sulfide, and solid impurities such as coal dust, rock fragments, and moisture. To meet the requirements for subsequent transportation and utilization, well sites are generally equipped with a complete set of purification equipment, including a filtration unit, a dehydration unit, and a purification unit for acidic components. Building upon this, it is also crucial to address acidic and harmful components in coalbed methane, such as hydrogen sulfide. Hydrogen sulfide is highly corrosive and toxic, causing severe corrosion and stress cracking not only to commonly used pipes, valves, and heat exchangers made of carbon steel and alloy steel, but also posing a threat to human health and safety at certain concentrations. Furthermore, it reduces the quality of coalbed methane products, hindering their subsequent utilization. While some well sites use activated carbon for hydrogen sulfide adsorption and purification, this process is relatively simple. However, once the activated carbon becomes saturated with hydrogen sulfide, it requires frequent replacement or regeneration. Cleaning and disposing of saturated activated carbon is not only cumbersome and labor-intensive, but also incurrs high replacement and regeneration costs, making it unsuitable for the continuous, stable, and economical operation requirements of well sites.

[0003] Chinese patent document (publication number: CN119875705A) discloses a purification device for coalbed methane extraction and production well sites, specifically relating to the technical field of purification devices. The device includes a main pipe, with a preliminary filter assembly fixedly installed at its upper end. A drying assembly is fixedly installed at its upper end, and a transmission assembly is fixedly installed on the lower rear side of the outer surface of the drying assembly. A mounting plate is fixedly connected to the upper part of the outer surface of the transmission assembly. This invention provides a purification device for coalbed methane extraction and production well sites. The preliminary filter assembly allows for rapid replacement of the filter and cleaning of its surface during use. The drying assembly improves the efficiency of subsequent coalbed methane drying, and the transmission assembly ensures thorough mixing of the dried coalbed methane with the internal amine solution, further enhancing the purification efficiency during coalbed methane extraction.

[0004] In existing technologies, when absorbing and separating acidic and harmful gases such as hydrogen sulfide in coalbed methane, the gas-liquid contact area is limited, the renewal interface is small, and the removal efficiency is low. When using gas lift mixing for removal, if the gas flow is unstable, the amine liquid may be introduced into the gas outlet, affecting the downstream processing and even corroding downstream pipelines or equipment. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a gas filtration device and method for coalbed methane extraction. By installing an injection component on the main coalbed methane delivery pipe, and sequentially connecting a first pipe, a second pipe, and a conical chamber downstream, a U-shaped gas lift channel and a conical chamber are formed into a circulating absorption unit. This allows the coalbed methane to repeatedly mix and contact with amine liquid drawn up from the conical chamber by the injection component within the compact pipeline, continuously updating the gas-liquid interface during the rising, tumbling, and falling circulation process. Simultaneously, an annular overflow channel is provided at the upper part of the conical chamber, and a liquid level adaptive adjustment mechanism consisting of a first float, a second float, and a plug is configured below it. This enables dynamic control and buffering of the liquid level in the conical chamber and the inner annular channel, preventing amine liquid from being carried into the gas outlet during airflow fluctuations and increasing the gas-liquid contact area and interface renewal frequency. Therefore, while ensuring the safety of downstream pipelines and equipment, this significantly improves the removal efficiency and operational stability of acidic harmful gases such as hydrogen sulfide from the coalbed methane.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A gas filtration device for coalbed methane development includes a main pipe. From the inlet end towards the equipment end, a filter assembly, a drying assembly, a compressor, and an injection assembly are sequentially arranged on the main pipe. The outlet end of the injection assembly is connected to a first pipe, which is connected to a second pipe. The other end of the second pipe is connected to a conical chamber, and the top of the conical chamber is connected to an outlet pipe. A return port is provided on the conical chamber, and the return port is connected to the side suction port of the injection assembly through a third pipe. The first pipe is connected to the second pipe via a bend, forming a U-shaped structure. Amine liquid is injected into both the first and second pipes. When the gas to be treated is introduced into the first pipe through the injection assembly, a gas lift effect is formed, pushing the amine liquid in the pipe into the conical chamber. After being fully mixed with the gas, it falls back into the pipe for further mixing. This gas lift cycle repeats, increasing the gas-liquid contact area.

[0007] Preferably, the spray assembly includes a cavity, a nozzle, and an outlet tube; the cavity is cylindrical, the nozzle extends into one end of the cavity to form an inlet, and the other end of the cavity is connected to the outlet tube to form an outlet; both the nozzle and the outlet tube are conical, with the small end of the nozzle located on the side closer to the outlet tube; the small end of the outlet tube is located on the side closer to the small end of the nozzle; a side suction port is provided on the side wall of the cavity, and the side suction port is connected to a third tube.

[0008] Preferably, the top of the conical chamber is provided with a ring-shaped buffer chamber, the bottom plate of the buffer chamber is provided with a drain port, the buffer chamber is a top-opening structure, the inner ring channel of the buffer chamber is connected to the conical chamber, the top of the buffer chamber is provided with a cone top, the cone top is provided with an opening, the cone top opening is connected to the air outlet pipe, and a filter screen is provided inside the air outlet pipe.

[0009] Preferably, two sets of guide rods are fixed at the bottom of the buffer chamber, with the two sets of guide rods located on both sides of the drain port. The other end of the guide rod is fixed to the inner wall of the conical chamber. A second float plate is slidably sleeved on the guide rod. A plug is fixed at the top of the second float plate, corresponding to the drain port, for detachable closure. A U-shaped frame is fixed at the bottom of the second float plate.

[0010] Preferably, a support mesh cover is provided above the bottom opening of the conical compartment. The outer periphery of the support mesh cover is fixed to the inner wall of the conical compartment by welding through connecting rods. A guide rod is welded and fixed to the top of the support mesh cover, and a cross rod is fixed to the guide rod. Each end of the cross rod is welded and fixed to the inner wall of the inner ring channel. A first float plate is slidably sleeved on the guide rod above the cross rod. A groove is opened on the first float plate along the length of the guide rod. A T-shaped plate is slidably installed inside the groove. A limiting groove is opened on the T-shaped plate corresponding to the cross rod. The T-shaped plate is slidably sleeved on the cross rod through the limiting groove. A hinge frame is provided at the end of the T-shaped plate away from the first float plate. A parallel bracket is fixed to the top of the support mesh cover on one side of the T-shaped plate. A lever is rotatably installed at the top of the parallel bracket through a pin. A closed strip groove is opened at the end of the lever near the T-shaped plate. A slide rod is provided at the end of the hinge frame. The slide rod slides through the strip groove. The end of the lever away from the hinge frame extends into the U-shaped frame.

[0011] Preferably, the lower part of the supporting net cover is pivotally connected to the disturbance net cover, and an n-shaped frame is fixed on the top of the disturbance net cover away from the pivot; a lifting rod is fixed parallel to the bottom end of the first floating plate, and the lifting rod slides through the supporting net cover and extends to the n-shaped frame. The ends of the two lifting rods are fixedly connected to a contact rod, and the contact rod extends into the interior of the n-shaped frame.

[0012] Preferably, an activated carbon adsorption unit is provided downstream of the gas outlet pipe, and a gas-liquid separator or condenser section is connected in series between the gas outlet pipe and the activated carbon adsorption unit.

[0013] Preferably, the filter assembly is an integrated cylindrical or canister-shaped shell structure, with an air inlet and an air outlet respectively connected to the main gas pipeline at both ends of the shell, and a detachable filter element arranged inside along the airflow direction.

[0014] Preferably, the drying assembly is a packing-type shell structure, with an air inlet and an air outlet at both ends of the shell that are connected to the main gas pipeline, and a detachable drying element arranged inside along the airflow direction.

[0015] Preferably, the operation method of the coalbed methane purification device includes the following steps: S1. Establishment of gas-liquid circulation and jet mixing: Pretreated coalbed methane is introduced into the injection assembly, and then the first and second pipes form an air lift effect to push the amine liquid into the conical chamber. The air lift effect causes the amine liquid to be pushed up into the conical chamber and then fall back down. A periodic gas-liquid circulation flow and liquid level fluctuation are established in the conical chamber and the inner ring channel. At the same time, the amine liquid in the conical chamber is continuously drawn into the injection assembly cavity and mixed with the intake air at high speed. S2, float plate follow-up, disturbance net cover drive and localized mixed reinforcement: In step S1, under the cyclic operating conditions and pressure fluctuations, the periodic changes in the amine liquid level in the conical chamber and inner ring channel drive the first float plate to move up and down. The lifting and lowering of the first float plate is transmitted to the contact rod through the lifting rod fixed at its bottom end. The contact rod periodically pulls or pushes the n-shaped frame and the disturbance net, causing the disturbance net to swing around the pivot. The disturbance net continuously disturbs and cuts the rising airflow and falling amine liquid in the bottom inlet area of ​​the conical chamber and near the supporting net, causing random turbulence and multi-directional splitting and recombination of the gas and liquid phases in this area, and continuously updating the local contact interface between the amine liquid and hydrogen sulfide in the coalbed methane. S3, Overflow buffer and dual float plate linkage drainage adjustment: When the device is at its normal liquid level and the second float is not submerged in amine, the second float and the plug move downwards by their own weight, opening the drain port and allowing amine that has entered the buffer chamber due to air lift or fluctuations to fall back into the conical chamber and lower pipe to participate in circulation. When the air lift increases, causing the amine to rise and submerge the second float, the buoyancy causes the second float to move upwards, driving the plug to close the drain port and preventing excessive liquid accumulation in the buffer chamber from causing the liquid level in the inner ring channel to be too low. When the amine liquid level in the conical chamber and the inner ring channel continues to rise and overflows into the buffer chamber through the annular overflow channel, the rising liquid level generates buoyancy on the first float, pushing the first float to move upwards along the guide rod. Through the hinged sliding cooperation of the T-plate and the lever, the second float and the plug are pressed down as a whole, opening the drain port and allowing the high-level amine liquid to be quickly drained back into the buffer chamber along the bottom channel of the conical chamber, preventing amine liquid from entering the gas outlet pipe, thus forming a liquid level fall and buffering mechanism that links the top overflow and the bottom drain. S4. Enhanced synergistic mass transfer and purification effects: The high-speed mixing formed by the injection components, the U-shaped airlift circulation in the first and second tubes, the continuous disturbance of the bottom area of ​​the conical chamber by the disturbance screen, and the adaptive liquid level regulation achieved by the inner ring channel in conjunction with the first float, the second float and the plug, ensure that the lower space of the conical chamber and the inner ring channel always maintain a high degree of turbulence and stable mass transfer efficiency, thereby improving the absorption rate and absorption efficiency of acidic gases such as hydrogen sulfide in the amine liquid.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention establishes an integrated vertical gas-liquid circulation removal structure by installing an injection component on the main coalbed methane delivery pipe and sequentially connecting a first pipe, a second pipe, and a conical chamber downstream of it. This allows the pre-treated coalbed methane to undergo enhanced absorption and separation of harmful components such as hydrogen sulfide upon entering the compact pipeline. The gas to be treated enters the U-shaped channel formed by the first and second pipes, generating a gas lift effect that pushes the amine liquid in the pipe to the conical chamber and then back into the pipe, forming a circulating flow that combines rising, tumbling, and falling. The injection component forms a high-speed jet within the cavity and introduces the amine liquid from the conical chamber, mixing it with the incoming gas. This allows the gas to contact the amine liquid multiple times within a limited space, renewing the interface and completing mass transfer, significantly improving removal efficiency and reducing equipment requirements. Compared to traditional tower or straight pipe arrangements, this design is more conducive to obtaining a uniform flow field and controllable residence time, thus achieving efficient purification and stable continuous operation of coalbed methane with a compact structure and small footprint.

[0017] 2. This invention features an annular overflow channel at the top of the conical chamber, and a liquid level regulating mechanism consisting of a first float, a second float, and a plug arranged below it. This forms an adaptive structure integrating gravity release, buoyancy self-closing, and air pressure linkage opening and closing, used to regulate the opening and closing state of the amine liquid channel between the buffer chamber and the conical chamber, maintaining a reasonable liquid level distribution in the inner annular channel and the conical chamber. Under normal operating conditions, the second float is not submerged, and its own weight drives the plug downward, keeping the drain port open. The amine liquid in the buffer chamber can promptly fall back into the conical chamber and the lower pipe to participate in circulation. When the air lift enhances and causes the amine liquid to rise and submerge the second float, the second float rises, driving the plug to close the drain port, preventing excessive liquid accumulation in the buffer chamber from affecting the inner annular channel. When the liquid level is too low, and the system pressure fluctuations cause the liquid level to rise and enter the buffer chamber through the overflow channel, the increased liquid level in the inner ring channel lifts the first float plate. With the help of the lever transmission of the T-shaped plate, lever, and U-shaped frame, the second float plate and the plug are pressed down, opening the drain port. This allows the high-level amine liquid to be quickly discharged into the buffer chamber through the bottom channel of the conical chamber, achieving coordinated backflow of top overflow and bottom drainage. Through the gravity opening and buoyancy self-closing of the second float plate and the forced opening of the first float plate at high liquid level, the drain port can automatically switch between discharge and interception according to the operating conditions. This ensures smooth amine liquid return and enhanced gas-liquid mixing at low liquid levels, while suppressing high liquid levels and liquid hammer under strong gas lift and pressure fluctuations, thus improving the liquid level control accuracy and operational stability of the device.

[0018] 3. This invention constructs a gas-liquid disturbance and enhanced mixing structure that adapts to working conditions by pivotally connecting a disturbance mesh cover below the support mesh cover inside the conical chamber and using the lifting and lowering motion of the first float to drive the disturbance mesh cover to swing. Under the combined influence of air lift and air pressure fluctuations, the amine liquid in the conical chamber and inner ring channel generates reciprocating disturbances due to the periodic rise and fall of the liquid level and gas impact, causing the first float to move up and down with the liquid level. The displacement of the first float is transmitted to the contact rod through the lifting rod, causing the contact rod to periodically push or pull the n-shaped frame, thereby driving the disturbance mesh cover to swing back and forth or at an indefinite angle around the pivot. This disturbance mesh cover is effective for the conical chamber. The rising airflow and falling amine liquid in the bottom inlet area and near the support mesh cover of the chamber form a continuous and random cutting and stirring. On the one hand, this enhances the local mixing and interface renewal of the gas and liquid phases in the lower space of the conical chamber, increasing the contact frequency and contact area between hydrogen sulfide and amine liquid. On the other hand, it works in conjunction with the high-speed mixing and U-shaped channel airlift circulation formed by the amine liquid introduced into the conical chamber by the injection component and the incoming gas, so that the device can maintain a high degree of turbulence and stable mass transfer efficiency under different gas and liquid flow conditions. This improves the absorption effect of acidic gases such as hydrogen sulfide and enhances the adaptability and operational stability of the overall separation process. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the device of the present invention; Figure 2 This is a three-dimensional cross-sectional view of the device of the present invention; Figure 3 This is a schematic cross-sectional view of the spray assembly of the device of the present invention; Figure 4 This is a three-dimensional schematic diagram of the internal structure of the conical chamber of the device of the present invention. Figure 1 ; Figure 5 This is a three-dimensional schematic diagram of the internal structure of the conical chamber of the device of the present invention. Figure 2 ; Figure 6 This is a schematic diagram of the linkage structure between the first float and the second float of the device of the present invention. Figure 7 This is a schematic diagram of the linkage structure between the disturbance net and the first floating plate of the device of the present invention; In the diagram: Injection assembly - 11; First tube - 12; Second tube - 13; Conical chamber - 14; Third tube - 15; Buffer chamber - 16; Outlet pipe - 17; Filter screen - 18; One-way valve - 19; Disturbance screen - 20; Support screen - 21; Inner ring channel - 22; First float - 23; Contact rod - 24; Swirl blade - 25; Cavity - 26; Nozzle - 27; Outlet pipe - 28; Cross rod - 29; Guide rod - 30; T-plate - 31; Limiting groove - 32; Drain port - 33; Return port - 34; Second float - 35; Plug - 36; U-shaped frame - 37; Parallel support - 38; Toggle rod - 39; Hinge frame - 40; Strip groove - 41; Filter assembly - 42; Drying assembly - 43; Compressor - 44; Pivot - 45; N-shaped frame - 46; Lifting rod - 47. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

[0021] Contents not described in detail in this specification are prior art known to those skilled in the art. In the description of this invention, it should be understood that terms such as "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the 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 the invention. Furthermore, terms such as "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] Figures 1-7As shown, a coalbed methane gas extraction device employs a gas filtration system, comprising a main pipe. From the inlet end towards the equipment end, the main pipe is sequentially equipped with a filter assembly 42, a drying assembly 43, a compressor 44, and an injection assembly 11. The outlet end of the injection assembly 11 is connected to a first pipe body 12, which is connected to a second pipe body 13. The other end of the second pipe body 13 is connected to a conical chamber 14, and the top of the conical chamber 14 is connected to an outlet pipe 17. A return port 34 is provided on the conical chamber 14, and the return port 34 is connected to the side suction port of the injection assembly 11 via a third pipe body 15. The first pipe body 12 is connected to the second pipe body 13 via a bend, forming a U-shaped structure. Amine liquid is injected into both the first and second pipe bodies 12 and 13. When the gas to be treated is introduced into the first pipe body through the injection assembly 11, a gas lift effect is formed, pushing the amine liquid in the pipe into the conical chamber 14. After being fully mixed with the gas, it falls back into the pipe body for further mixing. This gas lift cycle repeats, increasing the gas-liquid contact area. The second tube 13 is vertically arranged, while the first tube 12 is inclined, which is conducive to storing more amine liquid in the tube. The compressor can be a centrifugal compressor, equipped with adjustable guide vanes, and has a two-way pressure regulation function. In the boosting mode, the impeller rotates to accelerate the gas, and the diffuser converts kinetic energy into pressure energy; in the depressurization mode, the adjustable guide vane angle is reversed to expand the airflow and reduce pressure. By adjusting the pressure of the incoming airflow through the compressor, the amine liquid located inside the first tube 12 and the second tube 13 rises into the conical chamber 14, promoting the amine liquid to enter the conical chamber 14 and form a temporary dynamic equilibrium. After mixing, it falls into the tube for further mixing, without the need for other power settings. It should be noted that heating coils (not shown in the figure) are installed on the outer periphery of the first tube 12, the second tube 13, and the conical chamber 14 to ensure the ambient temperature for gas-liquid mixing. A one-way valve 19 is installed at the front end of the injection assembly 11 to prevent the medium in the device from flowing back into the ventilation channel when the gas supply is stopped; a swirl vane 25 is installed at the output end of the injection assembly to facilitate the formation of a swirl in the airflow inside the pipeline and promote gas-liquid mixing.

[0023] Furthermore, the spray assembly 11 includes a cavity 26, a nozzle 27, and an outlet pipe 28; the cavity 26 has a cylindrical structure, the nozzle 27 extends into one end of the cavity 26 to form an inlet, and the other end of the cavity 26 is connected to the outlet pipe 28 to form an outlet; both the nozzle 27 and the outlet pipe 28 have conical structures, the small end of the nozzle 27 is located on the side closer to the outlet pipe 28; the small end of the outlet pipe 28 is located on the side closer to the small end of the nozzle 27; a side suction port is provided on the side wall of the cavity 26, and the side suction port is connected to the third pipe 15; It should be noted that the injection assembly 11 uses the high-speed jet from the nozzle 27 to create a negative pressure zone within the cavity 26, thereby achieving the injection and mixing of the medium connected to the third tube 15. Specifically, the fluid medium is injected into the cylindrical cavity 26 at a high velocity through the small end of the nozzle 27, forming a high-speed jet and a significant decrease in static pressure near the outlet of the nozzle 27. As a result, a low-pressure zone is generated at the side suction port on the side wall of the cavity 26, causing the amine liquid or gas (when there is no amine liquid in the conical chamber) in the third tube 15 connected to the side suction port to be drawn into the cavity 26 and mixed turbulently with the mainstream jet from the nozzle 27 inside the cavity 26. The mixed gas flows to the other end of the cavity 26 and enters the outlet pipe 28 connected to it. Since the outlet pipe 28 is also a conical structure, its small end is located on the side close to the small end of the nozzle 27, and it is discharged after passing through the contraction and expansion sections of the outlet pipe 28. Without the need for external mechanical power, the injection assembly 11 relies on the high-speed jet formed by the nozzle 27 to draw and mix the amine liquid in the third tube 15, achieving full contact between the gas and the amine liquid and efficiently separating hydrogen sulfide. At the same time, the negative pressure of the side suction port disrupts the temporary balance of the amine liquid in the conical chamber 14, causing the amine liquid, which has risen due to the air lift effect, to fall back into the second and third tubes. As the amine liquid falls back into the second and third tubes, it changes the original liquid level distribution and flow path, causing the falling amine liquid to be disturbed and mixed again with the high-speed airflow ejected from the nozzle 27 in the tube, further enhancing the gas-liquid contact process and improving the overall efficiency and stability of hydrogen sulfide removal.

[0024] Furthermore, the top of the conical chamber 14 is provided with a ring-shaped buffer chamber 16. The bottom plate of the buffer chamber 16 is provided with a drain port 33. The buffer chamber 16 has a top opening structure. The inner ring channel 22 of the buffer chamber 16 is connected to the conical chamber 14. The top of the buffer chamber 16 is provided with a cone top. The cone top is provided with an opening. The cone top opening is connected to the air outlet pipe 17. A filter screen 18 is provided inside the air outlet pipe 17. It should be noted that the inner ring channel 22 is connected to the conical chamber 14, allowing the amine liquid in the conical chamber 14 under airlift to form a temporary dynamic equilibrium with the amine liquid in the inner ring channel 22 under certain air pressure conditions. When the system air pressure or volume fluctuates, this dynamic equilibrium is broken, and the amine liquid levels in the conical chamber 14 and the inner ring channel 22 rise accordingly. The higher-level amine liquid preferentially overflows from the top of the inner ring channel 22 into the buffer chamber 16, where it is temporarily intercepted. Afterward, it flows back to the conical chamber 14 from the drain port 33, thus preventing the amine liquid from directly entering the outlet pipe 17 located at the top of the buffer chamber 16. The cone top has an opening that connects to the gas outlet pipe 17, so that only the separated gas enters the buffer chamber 16 and then through the cone top opening into the gas outlet pipe 17. The filter screen 18 installed inside the gas outlet pipe 17 further intercepts the tiny droplets or foam particles of amine liquid carried by the airflow, causing them to coalesce and fall back into the cone chamber 14, and be discharged back to the lower part through the drain port 33. This effectively buffers and separates the upward surge and entrainment of amine liquid caused by gas lift and pressure fluctuations, ensuring that the coalbed gas entering the gas outlet pipe 17 is basically free of amine liquid, stabilizing the subsequent gas filtration and purification process and reducing corrosion and pollution to downstream equipment.

[0025] Furthermore, two sets of guide rods are fixed at the bottom of the buffer chamber 16. The two sets of guide rods are located on both sides of the drain port 33. The other end of the guide rod is fixed to the inner wall of the conical chamber 14. A second float plate 35 is slidably sleeved on the guide rod. A plug 36 is fixed at the top of the second float plate 35. The plug 36 is set corresponding to the drain port 33 for separable closure. A U-shaped frame 37 is fixed at the bottom of the second float plate 35. It should be noted that under normal operating conditions and when the second float 35 is not yet soaked in amine liquid, the second float 35 and the plug 36 are in a downward position along the guide rod under the action of gravity. At this time, the drain port 33 remains open, and the amine liquid that enters the buffer chamber 16 due to air lift or fluctuation can be discharged in time through the drain port 33 and fall back into the conical chamber 14 and the lower pipe body, which is conducive to the amine liquid re-entering the second and third pipe bodies to participate in gas-liquid mixing and circulation; when a large amount of amine liquid is pushed in due to air lift... When the conical chamber 14 rises to the bottom area of ​​the buffer chamber 16, the amine liquid soaks the second float plate 35. Under the action of buoyancy, the second float plate 35 moves upward along the guide rod, causing the plug 36 to rise and block the drain port 33. This prevents the amine liquid from continuing to flow into the buffer chamber 16 through the drain port 33 when the air lift is enhanced, thus avoiding the accumulation of liquid in the buffer chamber 16, which would cause the predetermined liquid level in the inner ring channel 22 to drop and affect the temporary dynamic equilibrium position of the amine liquid in the conical chamber 14 and the inner ring channel 22 established by the air lift. Through the above structural arrangement, the second float 35 and the plug 36 realize the gravity opening and buoyancy self-closing control of the discharge port 33, so that the amine liquid backflow between the buffer tank 16 and the conical tank 14 can be smoothly discharged at low level to enhance mixing, and can be automatically intercepted under strong air lift conditions to maintain a stable liquid level distribution in the inner ring channel 22 and the conical tank 14.

[0026] Furthermore, a support mesh cover 21 is provided above the bottom opening of the conical compartment 14. The outer periphery of the support mesh cover 21 is fixed to the inner wall of the conical compartment 14 by welding through connecting rods. A guide rod 30 is welded and fixed to the top of the support mesh cover 21, and a cross rod 29 is fixed to the guide rod 30. Each end of the cross rod 29 is welded and fixed to the inner wall of the inner ring channel 22. A first float plate 23 is slidably sleeved on the guide rod 30 above the cross rod 29. A groove is opened on the first float plate 23 along the length direction of the guide rod 30. A T-shaped plate 31 is slidably installed inside the groove. The T-shaped plate 31 is corresponding to the cross rod. A limiting groove 32 is provided on the rod, and the T-shaped plate 31 is slidably sleeved on the cross rod 29 through the limiting groove 32; a hinge frame 40 is provided on the end of the T-shaped plate 31 away from the first floating plate 23, and a parallel bracket 38 is fixed at the top of the support net cover 21 located on one side of the T-shaped plate 31. The top of the parallel bracket 38 is rotatably mounted with a lever 39 through a pin. A closed strip groove 41 is provided on the end of the lever 39 near the T-shaped plate 31. A sliding rod is provided at the end of the hinge frame 40, and the sliding rod slides through the strip groove 41. The end of the lever 39 away from the hinge frame 40 extends into the U-shaped frame 37. Among them, the cross-section of the guide rod 30 is rectangular, which can play a guiding role and limit the position of the float to prevent rotation or unknown displacement. It should be noted that when system pressure fluctuations cause the amine liquid level in the conical chamber 14 and the inner ring channel 22 to rise and overflow into the buffer chamber 16 through the top of the inner ring channel 22, the amine liquid in the inner ring channel 22 exerts buoyancy on the first float plate 23, causing the first float plate 23 to move upward along the guide rod 30, and simultaneously driving the T-shaped plate 31 connected to it to move upward. The T-shaped plate 31, through the hinged sliding engagement with the lever 39, causes the lever 39 to swing around the pin shaft. The end of the lever 39 away from the hinge frame 40 is pressed downward into the U-shaped frame 37, thereby driving the lever 39 to move upward through the lever amplification effect. The second float 35 and the plug 36 are moved down as a whole, so that the plug 36 is separated from the drain port 33 and the drain port 33 is opened. The amine liquid located in the high area of ​​the inner ring channel 22 of the conical chamber 14 is rapidly poured into the buffer chamber 16 through the drain port 33 through the bottom channel of the conical chamber 14 under the action of air pressure and liquid level difference. This allows the high-level amine liquid in the inner ring channel 22 and the conical chamber 14 to be quickly introduced into the buffer chamber 16 from the bottom path. This helps to quickly reduce the liquid level in the inner ring channel 22 when there are air pressure fluctuations and liquid level surges, and avoids the amine liquid from being in a high liquid level state for a long time and disrupting the predetermined gas-liquid balance position. The first floating plate 23 keeps a certain distance from the transverse plate end of the T-shaped plate 31. When the second floating plate 35 moves up and down, there is no driving behavior on the first floating plate 23 through the T-shaped plate, that is, no interference phenomenon will occur; when the first floating plate 23 rises due to the buoyancy of the high liquid level, the first floating plate 23 will first complete the fixed-distance stroke of the end of the T-shaped plate and then contact and drive the transverse plate of the T-shaped plate.

[0027] Furthermore, the lower part of the support mesh cover 21 is rotationally connected to the disturbance mesh cover 20 through a pivot 45. On one side of the top end of the disturbance mesh cover 20 far from the pivot 45, an n-shaped frame 46 is fixedly arranged; lifting rods 47 are fixedly arranged in parallel at the bottom end of the first floating plate 23. The lifting rods 47 slide through the support mesh cover 21 and then extend to the n-shaped frame 46. The ends of the two lifting rods 47 are fixedly connected to a contact rod 24, and the contact rod 24 extends into the n-shaped frame 46. It should be noted that under the air-lift effect and the air pressure fluctuation working conditions, the amine liquid in the conical bin 14 and the inner ring channel 22 generates periodic lifting and disturbance due to the liquid level change or gas impact, driving the first floating plate 23 to move up and down with the liquid level change. The up and down movement of the first floating plate 23 is transmitted to the contact rod 24 through the lifting rod 47, causing the contact rod 24 to periodically push or drive the n-shaped frame 46, thereby driving the hinged disturbance mesh cover 20 to swing reciprocally or at an indefinite angle around the pivot 45, forming continuous and random disturbance and cutting on the gas-liquid two-phase flow in the bottom inlet area of the conical bin 14 and near the support mesh cover 21, promoting the full contact and mixing of the amine liquid and hydrogen sulfide in the lower space of the conical bin 14. On the other hand, in cooperation with the injection component and the air-lift cycle, the system can still maintain a strong degree of turbulence and mass transfer efficiency under different working conditions, thereby improving the absorption effect of acidic gases such as hydrogen sulfide and enhancing the overall separation stability.

[0028] Furthermore, an activated carbon adsorption unit is arranged downstream of the air outlet pipe 17, and a gas-liquid separator or a condensation section is connected in series between the air outlet pipe 17 and the activated carbon adsorption unit; The gas-liquid separator or the condensation section is used for further pretreatment of the coalbed methane discharged through the air outlet pipe 17. Through condensation and gravity separation, a small amount of residual moisture and fog-like amine liquid in the gas are removed, so that the coalbed methane entering the activated carbon device is in a state with lower water content and basically no entrained fog-like amine liquid, thereby reducing the infiltration and blockage of the activated carbon pores by the liquid, ensuring the adsorption efficiency of the activated carbon device and prolonging its service life.

[0029] Furthermore, the filter component 42 is an integrated cylindrical or tank-shaped shell structure. An air inlet and an air outlet communicated with the gas main pipeline are respectively arranged at both ends of the shell, and a detachable filter element is arranged inside along the air flow direction; It should be noted that the filter element is preferably a multi-layer stainless steel wire mesh, a sintered metal filter element, or a pleated metal filter element, with a filtration accuracy of generally 50 to 200 micrometers, in order to effectively intercept solid particulate impurities such as coal dust, sand, and rust in coalbed methane; an openable inspection port or quick-opening end cover is provided on the side or top of the shell for disassembling and replacing the filter element; a drain port and drain valve are provided at the bottom of the shell for periodically discharging deposited solid impurities and condensate to prevent impurities from accumulating at the bottom of the shell for a long time.

[0030] Furthermore, the drying assembly 43 is a packing-type shell structure, with an air inlet and an air outlet at both ends of the shell that are connected to the main gas pipeline, and a detachable drying element is arranged inside along the airflow direction. The drying component 43 is a packed or cylindrical drying shell structure. The shell has an air inlet and an air outlet at both ends that are connected to the main gas pipeline. The interior is provided with a detachable drying element or desiccant-filled chamber along the airflow direction. The drying element is preferably a cylindrical filter element filled with solid moisture-absorbing materials such as molecular sieves, activated alumina, and silica gel, or a fixed bed structure filled with the above-mentioned desiccant particles, so as to achieve physical adsorption and drying of moisture in coalbed methane.

[0031] The operation method of the coalbed methane purification device includes the following steps: S1. Establishment of gas-liquid circulation and jet mixing: Pretreated coalbed methane is introduced into the injection assembly 11, and then sequentially through the first pipe 12 and the second pipe 13 to form an air lift effect that pushes the amine liquid into the conical chamber 14. The air lift effect causes the amine liquid to be pushed up to the conical chamber 14 and then fall back down. A periodic gas-liquid circulation flow and liquid level fluctuation are established in the conical chamber 14 and the inner ring channel 22. At the same time, the amine liquid in the conical chamber 14 is continuously drawn into the cavity of the injection assembly 11 and mixed with the intake air at high speed. S2, float plate follow-up, disturbance net cover drive and localized mixed reinforcement: Under the cyclical working condition and pressure fluctuations in step S1, the periodic changes in the amine liquid level in the conical chamber 14 and the inner ring channel 22 drive the first float 23 to move up and down. The rise and fall of the first float 23 is transmitted to the contact rod 24 through the lifting rod 47 fixed at its bottom end. The contact rod 24 periodically pulls or pushes the n-shaped frame 46 and the disturbance net cover 20, causing the disturbance net cover 20 to swing around the pivot 45. The disturbance net cover 20 continuously disturbs and cuts the rising airflow and falling amine liquid in the bottom inlet area of ​​the conical chamber 14 and near the support net cover 21, causing random turbulence and multi-directional splitting and recombination of the gas and liquid phases in this area, and continuously updating the local contact interface between the amine liquid and the hydrogen sulfide in the coalbed methane. S3, Overflow buffer and dual float plate linkage drainage adjustment: When the device is at its normal liquid level and the second float 35 is not submerged in amine liquid, the second float 35 and the plug 36 move downwards under their own weight, causing the drain port 33 to open. This allows the amine liquid that has entered the buffer chamber 16 due to air lift or fluctuations to fall back into the conical chamber 14 and the lower pipe to participate in circulation. When the air lift increases, causing the amine liquid to rise and submerge the second float 35, the buoyancy causes the second float 35 to move upwards, driving the plug 36 to close the drain port 33, preventing excessive liquid accumulation in the buffer chamber 16 and causing the liquid level in the inner ring channel 22 to become too low. When the conical chamber 14 and the inner ring channel 22 are at their normal liquid levels, the amine liquid is drawn downwards by the weight of the second float 35 and the plug 36 to open. When the amine liquid level in 2 continues to rise and overflows into the buffer chamber 16 through the annular overflow channel 22, the rising liquid level generates buoyancy on the first float 23, pushing the first float 23 to move upward along the guide rod 30. Through the hinged sliding cooperation of the T-shaped plate 31 and the lever 39, the second float 35 and the plug 36 are pressed down as a whole, opening the drain port 33, so that the high-level amine liquid is quickly guided back to the buffer chamber 16 along the bottom channel of the conical chamber 14, preventing the amine liquid from entering the vent pipe 17, forming a liquid level drop and buffering mechanism that links the top overflow and the bottom drain. S4. Enhanced synergistic mass transfer and purification effects: The high-speed mixing formed by the injection assembly 11, the U-shaped airlift circulation in the first tube 12 and the second tube 13, the continuous disturbance of the bottom area of ​​the conical chamber 14 by the disturbance screen 20, and the adaptive liquid level adjustment synergistic effect achieved by the inner ring channel 22 in conjunction with the first float 23, the second float 35 and the plug 36, ensure that the lower space of the conical chamber 14 and the inner ring channel 22 always maintain a high degree of turbulence and stable mass transfer efficiency, thereby improving the absorption rate and absorption efficiency of acidic gases such as hydrogen sulfide in the amine liquid.

[0032] The present invention has been illustrated through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that all related improvements to the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A gas filtration device for coalbed methane development, comprising a main pipe, wherein a filter assembly (42), a drying assembly (43), a compressor (44), and an injection assembly (11) are sequentially arranged from the gas inlet end toward the equipment end, characterized in that, The outlet end of the injection assembly (11) is connected to the first tube (12), the first tube (12) is connected to the second tube (13), the other end of the second tube (13) is connected to the conical chamber (14), and the top of the conical chamber (14) is connected to the gas outlet pipe (17). A return port (34) is provided on the conical chamber (14), and the return port (34) is connected to the side suction port of the injection assembly (11) through the third tube (15). The first tube (12) is connected to the second tube (13) through a bend and forms a U-shaped structure. Amine liquid is injected into the first tube (12) and the second tube (13). When the gas to be treated is introduced into the first tube through the injection assembly (11), a gas lift effect is formed, which pushes the amine liquid in the tube into the conical chamber (14), mixes it thoroughly with the gas, and then falls back into the tube to mix again. This cycle of gas lift is repeated to increase the gas-liquid contact area.

2. The gas filtration device for coalbed methane extraction according to claim 1, characterized in that, The spray assembly (11) includes a cavity (26), a nozzle (27), and an outlet pipe (28); the cavity (26) is a cylindrical structure, the nozzle (27) extends into one end of the cavity (26) to form an inlet, and the other end of the cavity (26) is connected to the outlet pipe (28) to form an outlet; both the nozzle (27) and the outlet pipe (28) are conical structures, the small end of the nozzle (27) is located on the side close to the outlet pipe (28); the small end of the outlet pipe (28) is located on the side close to the small end of the nozzle (27); a side suction port is provided on the side wall of the cavity (26), and the side suction port is connected to the third pipe (15).

3. The gas filtration device for coalbed methane extraction according to claim 1, characterized in that, The top of the conical chamber (14) is provided with a ring-shaped buffer chamber (16). The bottom plate of the buffer chamber (16) is provided with a drain port (33). The buffer chamber (16) has a top opening structure. The inner ring channel (22) of the buffer chamber (16) is connected to the conical chamber (14). The top of the buffer chamber (16) is provided with a cone top. The cone top is provided with an opening. The cone top opening is connected to the air outlet pipe (17). A filter screen (18) is provided inside the air outlet pipe (17).

4. The gas filtration device for coalbed methane extraction according to claim 3, characterized in that, Two sets of guide rods are fixed at the bottom of the buffer chamber (16). The two sets of guide rods are located on both sides of the drain port (33). The other end of the guide rod is fixed to the inner wall of the conical chamber (14). A second float plate (35) is slidably sleeved on the guide rod. A plug (36) is fixed at the top of the second float plate (35). The plug (36) is set corresponding to the drain port (33) for separable closure. A U-shaped frame (37) is fixed at the bottom of the second float plate (35).

5. The gas filtration device for coalbed methane extraction according to claim 4, characterized in that, A support mesh cover (21) is provided above the bottom opening of the conical chamber (14). The outer periphery of the support mesh cover (21) is fixed to the inner wall of the conical chamber (14) by welding through connecting rods. A guide rod (30) is welded and fixed to the top of the support mesh cover (21). A cross rod (29) is fixed on the guide rod (30). Each end of the cross rod (29) is welded and fixed to the inner wall of the inner ring channel (22). A first float plate (23) is slidably sleeved on the guide rod (30) above the cross rod (29). A groove is opened on the first float plate (23) along the length direction of the guide rod (30). A T-shaped plate (31) is slidably installed inside the groove. A limit is opened on the T-shaped plate (31) corresponding to the cross rod. The slide groove (32) and the T-shaped plate (31) are slidably sleeved on the cross rod (29) through the limiting slide groove (32); the end of the T-shaped plate (31) away from the first floating plate (23) is provided with a hinge frame (40); the top of the support net cover (21) located on one side of the T-shaped plate (31) is fixed with a parallel bracket (38); the top of the parallel bracket (38) is rotatably installed with a lever (39) through a pin; the end of the lever (39) near the T-shaped plate (31) is provided with a closed strip groove (41); the end of the hinge frame (40) is provided with a sliding rod; the sliding rod slides through the strip groove (41); the end of the lever (39) away from the hinge frame (40) extends into the U-shaped frame (37).

6. The gas filtration device for coalbed methane extraction according to claim 5, characterized in that, The support net cover (21) is rotatably connected to the disturbance net cover (20) via a pivot (45) below. An n-shaped frame (46) is fixed on the top of the disturbance net cover (20) away from the pivot (45). A lifting rod (47) is fixed parallel to the bottom of the first float (23). The lifting rod (47) slides through the support net cover (21) and extends to the n-shaped frame (46). The ends of the two lifting rods (47) are fixedly connected to a contact rod (24), which extends into the n-shaped frame (46).

7. The gas filtration device for coalbed methane extraction according to claim 1, characterized in that, An activated carbon adsorption unit is provided downstream of the gas outlet pipe (17), and a gas-liquid separator or condenser is connected in series between the gas outlet pipe (17) and the activated carbon adsorption unit.

8. The gas filtration device for coalbed methane extraction according to claim 1, characterized in that, The filter assembly (42) is an integral cylindrical or canister-shaped shell structure. The two ends of the shell are respectively provided with an air inlet and an air outlet connected to the gas main pipeline. The interior is provided with a detachable filter element along the airflow direction.

9. The gas filtration device for coalbed methane extraction according to claim 1, characterized in that, The drying component (43) is a packing-type shell structure. The shell has an air inlet and an air outlet at both ends that are connected to the gas pipeline. The interior is equipped with a detachable drying element along the airflow direction.

10. The method of operating the coalbed methane purification device according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Establishment of gas-liquid circulation and jet mixing: The pretreated coalbed methane is introduced into the injection assembly (11), and then the first pipe (12) and the second pipe (13) form an air lift effect to push the amine liquid into the conical chamber (14). The air lift effect causes the amine liquid to be pushed up to the conical chamber (14) and then fall back. A periodic gas-liquid circulation flow and liquid level fluctuation are established in the conical chamber (14) and the inner ring channel (22). At the same time, the amine liquid in the conical chamber (14) is continuously drawn into the cavity of the injection assembly (11) and mixed with the intake air at high speed. S2, float plate follow-up, disturbance net cover drive and localized mixed reinforcement: In step S1, under the cyclic operating conditions and pressure fluctuations, the periodic changes in the amine liquid level in the conical chamber (14) and the inner ring channel (22) drive the first float (23) to move up and down. The rise and fall of the first float (23) is transmitted to the contact rod (24) through the lifting rod (47) fixed at its bottom end. The contact rod (24) periodically pulls or pushes the n-shaped frame (46) and the disturbance net (20), causing the disturbance net (20) to swing around the pivot (45). The disturbance net (20) continuously disturbs and cuts the rising airflow and falling amine liquid in the bottom inlet area of ​​the conical chamber (14) and near the support net (21), causing the gas and liquid phases in this area to generate random turbulence and multi-directional splitting and recombination, constantly updating the local contact interface between the amine liquid and the hydrogen sulfide in the coalbed methane. S3, Overflow buffer and dual float plate linkage drainage adjustment: When the device is at its normal liquid level and the second float (35) is not submerged in amine liquid, the second float (35) and the plug (36) move downwards by their own weight, causing the drain port (33) to open, allowing the amine liquid that has entered the buffer chamber (16) due to air lift or fluctuation to fall back into the conical chamber (14) and the lower pipe to participate in circulation; when the air lift is enhanced, causing the amine liquid to rise and submerge the second float (35), the buoyancy causes the second float (35) to move upwards, driving the plug (36) to close the drain port (33), preventing excessive liquid accumulation in the buffer chamber (16) from causing the liquid level in the inner ring channel (22) to be too low; when the conical chamber (14) and the inner ring channel (2 When the amine liquid level in 2) continues to rise and overflows into the buffer chamber (16) through the annular overflow channel (22), the rising liquid level generates buoyancy on the first float (23), pushing the first float (23) to move upward along the guide rod (30). Through the hinged sliding cooperation of the T-shaped plate (31) and the lever (39), the second float (35) and the plug (36) are pressed down as a whole, opening the drain port (33), so that the high-level amine liquid is quickly guided back to the buffer chamber (16) along the bottom channel of the conical chamber (14), avoiding the amine liquid from entering the gas outlet pipe (17), forming a liquid level drop and buffering mechanism that links the top overflow and the bottom drain. S4. Enhanced synergistic mass transfer and purification effects: The high-speed mixing formed by the injection assembly (11), the U-shaped airlift circulation in the first tube (12) and the second tube (13), the continuous disturbance of the bottom area of ​​the conical chamber (14) by the disturbance screen (20), and the adaptive liquid level adjustment synergistic effect achieved by the inner ring channel (22) in conjunction with the first float (23), the second float (35) and the plug (36) ensure that the lower space of the conical chamber (14) and the inner ring channel (22) always maintain a high degree of turbulence and stable mass transfer efficiency, thereby improving the absorption rate and absorption efficiency of acidic gases such as hydrogen sulfide in the amine liquid.

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