Membrane separation efficient natural gas purification system energy-saving optimization device

Abstract

The invention belongs to the technical field of natural gas, and particularly relates to a membrane separation efficient natural gas purification system energy-saving optimization device which comprises a machine body, a membrane assembly used for purifying natural gas, a venturi tube installed in the machine body, and a gas inlet pipe connected with the venturi tube and a second discharge pipe connected with the venturi tube. A plurality of air suction structures are linearly distributed on the Venturi tube in the axis direction of the machine body, each air suction structure is composed of a contraction section, a throat part and a diffusion section, and an air guide-in hole is formed in the throat part; the spiral rotating shaft is arranged in the machine body; due to the adoption of the annular coaxial layout and the one-way flow channel design, the feed gas keeps a one-way advancing track in the whole process, a reverse backflow channel is avoided, vertical layered space isolation is formed between the feed gas and newly input feed gas above the feed gas, cross mixing of gas in different stages is avoided, continuous treatment is uninterrupted, an intermittent cavity switching mode is abandoned, and the production efficiency is improved. Raw material gas is continuously fed, decarburized gas is continuously discharged, and no shutdown switching time is consumed.

Description

Technical Field

[0001] This invention belongs to the field of natural gas, specifically an energy-saving optimization device for a membrane separation high-efficiency natural gas purification system. Background Technology

[0002] The membrane separation high-efficiency natural gas purification system energy-saving optimization device is a special equipment for membrane separation technology designed specifically for natural gas purification. Natural gas, as a clean and efficient energy source, is widely used in industrial production, urban gas, transportation and other fields. However, during the extraction and pretreatment process, it is often accompanied by impurities such as carbon dioxide, water and heavy hydrocarbons. These impurities not only reduce the calorific value of natural gas, but may also cause pipeline corrosion, equipment blockage, and even hydrate formation during low-temperature transportation, leading to pipeline paralysis. At the same time, acidic gases can also cause environmental pollution. Therefore, natural gas purification is a key pre-processing step in its processing.

[0003] A patent application with publication number CN119680357A discloses a natural gas decarbonization device, including a processing tank with an inlet pipe on the outside, a liquid injection pipe, and a carbon dioxide absorption pipe rotatably installed inside the processing tank; a rotor fixed to the outside of the carbon dioxide absorption pipe and rotatably connected to the inner wall of the processing tank; decarbonization chambers radially arranged on the rotor, with a semi-permeable membrane assembly detachably fixed inside each decarbonization chamber; by driving the rotor to rotate, natural gas is intermittently injected into each decarbonization chamber, and the natural gas is decarbonized and discharged during one rotation of the rotor.

[0004] While this approach avoids mixing of newly input natural gas with decarbonized natural gas, thus ensuring stable decarbonization results, it has significant limitations: Firstly, the intermittent decarbonization chamber processing mode limits the single-batch processing capacity to the number and volume of chambers, resulting in low overall efficiency and making it difficult to meet the demands of large-scale continuous purification. Secondly, to achieve the intermittent processing requirements, the device needs to be designed with rotor drives, chamber switching, and other supporting structures, increasing overall structural complexity, which not only increases equipment manufacturing and maintenance costs but may also reduce operational reliability.

[0005] Therefore, the present invention provides an energy-saving optimization device for a membrane separation high-efficiency natural gas purification system. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0007] The technical solution adopted by this invention to solve its technical problem is as follows: An energy-saving optimization device for a high-efficiency natural gas purification system using membrane separation, comprising a body and a membrane module for purifying natural gas. The membrane module includes a support and a separation membrane. The body is connected to an inlet pipe and a first outlet pipe. It also includes a Venturi tube installed within the body, the Venturi tube having multiple suction structures linearly distributed along the axis of the body. Each suction structure consists of a converging section, a throat, and a diffuser section. A gas inlet hole is provided on the throat. The membrane module and the Venturi tube are both annularly installed within the body, with the membrane module located inside the Venturi tube. A rotatable spiral shaft is installed within the body, the spiral shaft being positioned on the inner circumference of the membrane module. The inlet pipe is located above the body, and the first outlet pipe is located in the lower middle part of the body.

[0008] Preferably, the device further includes: a partition plate installed inside the machine body, the partition plate dividing the interior of the machine body into a first chamber and a second chamber that are not interconnected, the first chamber being used to purify natural gas, and the second chamber being used to contain absorbent liquid, the partition plate being hollow, and the venturi tube being connected to the partition plate; and a gas guide pipe installed on the partition plate, the gas guide pipe being used to guide the gas flowing in the venturi tube into the absorbent liquid.

[0009] Preferably, the diameter of the spiral shaft gradually increases from top to bottom, and the throat size of the air intake structure decreases in a stepped manner from top to bottom.

[0010] Preferably, the device further includes: a plurality of connecting holes formed on the body; a first annular plate installed on the body, wherein an adsorbent desiccant is installed inside the first annular plate, and the first annular plate is connected to the second cavity through the connecting holes; a second annular plate installed on the body, wherein a buffer cavity is provided inside the second annular plate; a plurality of second pipes for connecting the Venturi tube and the buffer cavity; and a circulation pump installed between the second annular plate and the first annular plate, wherein the input end of the circulation pump is connected to the first annular plate and the output end is connected to the buffer cavity, for drying the gas in the second cavity with the adsorbent desiccant and then reintroducing it into the Venturi tube for recycling.

[0011] Preferably, a tubular sieve plate is installed at the end of the gas guide tube. The tubular sieve plate divides the gas introduced into the absorbent liquid into tiny bubbles through a number of sieve holes on its tube wall, thereby increasing the contact area between the gas and the absorbent liquid.

[0012] Preferably, the tubular sieve plate is rotatably connected to the air guide pipe, and an impeller is fixedly installed inside the tubular sieve plate.

[0013] Preferably, a check valve is installed on both the feed pipe and the first discharge pipe, and the check valve is used to restrict the direction of gas flow.

[0014] Preferably, the device further includes: a plurality of holes No. 1 formed inside the spiral shaft, the spiral shaft having a hollow structure, the gas being discharged from the holes No. 1 and sprayed at an inclined angle with the membrane assembly; a cylinder rotatably installed inside the spiral shaft, the cylinder having holes No. 2; a connector rotatably installed above the spiral shaft, the connector communicating with the spiral shaft, the connector being fixedly installed on the machine body, the connector having a second air inlet pipe; and a second discharge pipe installed on the machine body, the second discharge pipe passing through the partition plate and communicating with the first cavity.

[0015] Preferably, the device further includes: an exhaust pipe installed on the machine body, the exhaust pipe having a second one-way valve, the exhaust pipe communicating with the second chamber; a round rod slidably installed on the spiral shaft, the round rod being threadedly connected to the cylinder, the round rod having a third hole communicating with the interior of the spiral shaft; and a torsion spring installed between the round rod and the cylinder.

[0016] Preferably, the device further includes: a buffer tank installed on the periphery of the machine body; a first air inlet pipe and an air outlet pipe installed on the buffer tank, the first air inlet pipe and the air outlet pipe being connected to the first discharge pipe and the second discharge pipe respectively; and two electromagnetic three-way valves installed on the first air inlet pipe and the first discharge pipe, and on the air outlet pipe and the second discharge pipe respectively.

[0017] The beneficial effects of this invention are as follows: 1. The energy-saving optimization device for a membrane separation high-efficiency natural gas purification system described in this invention guides the raw gas to form a stable spiral downward flow state through a spiral rotating shaft. Combined with the annular flow channel design, it constructs a unidirectional flow channel without backmixing or recirculation. This not only forms a spatial isolation with the newly input gas, avoiding the problem of cross-mixing, but also allows for continuous feeding of raw gas and continuous discharge of decarbonized gas. There is no need to stop the machine to switch chambers, and the purification efficiency is significantly improved.

[0018] 2. The energy-saving optimization device for a high-efficiency natural gas purification system using membrane separation described in this invention dynamically compensates for the reduction in gas volume caused by the continuous separation of carbon dioxide by gradually increasing the diameter of the spiral shaft. This effectively maintains stable pressure within the flow channel and avoids the reduction in separation efficiency caused by pressure drop. At the same time, the stepwise reduction in the size of the venturi throat creates a gradient low-pressure field that is weaker at the top and stronger at the bottom, precisely matching the separation process. That is, when the raw material gas flows to the bottom, its carbon dioxide concentration decreases and the separation resistance increases. At this time, the stronger low-pressure adsorption force can provide sufficient separation driving force to overcome the permeation barrier at low concentration, thereby ensuring the high purity of the final product gas.

[0019] 3. The energy-saving optimization device for a membrane separation high-efficiency natural gas purification system described in this invention, through the setting of carbon dioxide absorbent and nitrogen circulation, allows the separated nitrogen to be dried and purified and reused for venturi tube drive, which greatly reduces nitrogen replenishment consumption, significantly reduces material costs for long-term operation, and takes into account both energy saving and efficient resource utilization.

[0020] 4. The energy-saving optimization device for a high-efficiency natural gas purification system using membrane separation described in this invention, through the setting of the cleaning port, allows the membrane module to be purged with nitrogen without disassembling the device. In conjunction with the buffer tank and the electromagnetic three-way valve, the residual raw material gas in the first chamber is first introduced into the buffer tank for storage, avoiding waste caused by the discharge of impurity gas during purging. Attached Figure Description

[0021] The invention will now be further described with reference to the accompanying drawings.

[0022] Figure 1 This is a perspective view of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the internal structure of the body of the present invention; Figure 3 This is a schematic diagram of the internal structure of the Venturi tube of the present invention; Figure 4 This is a plan view of the spiral shaft of the present invention; Figure 5 This is a cross-sectional view of the spiral shaft of the present invention; Figure 6 This is an exploded view of the tubular sieve plate and impeller of the present invention; Figure 7 This is a bottom view of the spiral shaft of the present invention; Figure 8 This is a schematic diagram showing the position of the cylinder of the present invention; Figure 9 yes Figure 5 Enlarged view of a portion of point A in the middle; In the diagram: 1. Machine body; 2. Membrane module; 3. Feed pipe; 4. No. 1 discharge pipe; 5. Venturi tube; 6. Intake structure; 7. Gas inlet hole; 8. Spiral shaft; 9. Separator plate; 10. No. 1 chamber; 11. No. 2 chamber; 12. Air guide pipe; 13. Connecting hole; 14. No. 1 annular plate; 15. No. 2 annular plate; 16. Buffer chamber; 17. No. 2 pipe; 18. Circulating pump; 19. Tubular screen plate; 20. Impeller; 21. No. 1 check valve; 22. No. 1 hole; 23. Cylinder; 24. No. 2 hole; 25. Connector; 26. No. 2 air inlet pipe; 27. No. 2 discharge pipe; 28. Exhaust pipe; 29. ​​No. 2 check valve; 30. Round rod; 31. No. 3 hole; 32. Buffer tank; 33. No. 1 air inlet pipe; 34. Air outlet pipe; 35. Solenoid three-way valve. Detailed Implementation

[0023] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0024] like Figures 1-9 As shown in the figure, an energy-saving optimization device for a high-efficiency natural gas purification system using membrane separation according to an embodiment of the present invention includes a body 1 and a membrane module 2 for purifying natural gas. The membrane module 2 includes a support and a separation membrane. The body 1 is connected to an inlet pipe 3 and a first outlet pipe 4. The device also includes a Venturi tube 5 installed inside the body 1. The Venturi tube 5 has multiple air intake structures 6 linearly distributed along the axial direction of the body 1. Each air intake structure 6 consists of a converging section, a throat, and a diffuser section. A gas inlet hole 7 is provided on the throat. The membrane module 2 and the Venturi tube 5 are both installed in a ring shape inside the body 1, with the membrane module 2 located inside the Venturi tube 5. A spiral shaft 8 is rotatably installed inside the body 1. The spiral shaft 8 is located on the inner circumference of the membrane module 2. The inlet pipe 3 is located above the body 1, and the first outlet pipe 4 is located in the lower middle part of the body 1.

[0025] Specifically, existing technologies employ an intermittent decarbonization chamber processing mode to avoid mixing of newly input natural gas with decarbonized natural gas. However, this mode has significant limitations: on the one hand, the single batch processing capacity is limited by the number and volume of chambers, resulting in low overall efficiency and making it difficult to meet the needs of large-scale continuous purification; on the other hand, to achieve the process requirements of intermittent processing, the device needs to be designed with supporting structures such as rotor drive and chamber switching, which increases the overall structural complexity, not only increasing the cost of equipment manufacturing and maintenance but also potentially reducing operational reliability. Before operation, fluid is introduced into the Venturi tube 5. The fluid will generate low pressure when it flows through the throat. The feed pipe 3 is connected to the gas supply system. During operation, the raw gas is controlled to enter from the feed pipe 3 at the top of the machine body 1. After the raw gas enters vertically from the feed pipe 3 at the top of the machine body 1, it flows downward along the inner circumference of the membrane module 2 under the guidance of the spiral shaft 8. It maintains a unidirectional trajectory throughout the process and there is no reverse flow channel. As the raw gas flows downward in a spiral, it fully contacts the membrane module 2. During this process, the carbon dioxide in the raw gas is adsorbed by the low pressure of the Venturi tube 5, passes through the membrane module 2 and is drawn into the Venturi tube 5. Finally, it is carried out by the fluid and discharged. The decarbonized target natural gas continues to flow downward along the predetermined channel and is discharged from the No. 1 discharge pipe 4, completing the high-efficiency purification. During normal operation, the spiral shaft 8 rotates at low speed, which minimizes airflow disturbance and ensures stable flow of raw material gas. It also allows carbon dioxide to enter each gas inlet hole 7 evenly. The rotation of the spiral shaft 8 is electrically driven. Due to the adoption of a ring-shaped coaxial layout and unidirectional flow channel design, the raw material gas maintains a unidirectional travel trajectory throughout the process, with no reverse return channel. It forms a spatial isolation between the upper and lower layers with the newly input raw material gas above, avoiding cross-mixing of gases at different stages. The separated carbon dioxide is directly drawn into the throat of the Venturi tube 5 at low pressure after passing through the membrane module 2, and is quickly discharged from the body 1 with the fluid, without entering the target gas flow channel, further eliminating the risk of mixing. The continuous processing eliminates the need for intermittent chamber switching, allowing for continuous feeding of raw gas and continuous discharge of decarbonized gas without downtime or switching, resulting in higher working efficiency. In addition, the spiral shaft 8 guides the raw gas to form a spiral downward flow, which greatly increases the contact area and contact time between the raw gas and the annular membrane module 2. Combined with the uniform low-pressure field formed by multiple air intake structures 6 distributed along the axis of the venturi tube 5, it ensures more complete carbon dioxide separation and penetration, further improving purification efficiency. The simplified structure reduces energy consumption. The complex rotor drive and chamber sealing structure are eliminated, and efficient separation is achieved through the synergistic effect of the spiral shaft 8 and the venturi tube 5, which significantly reduces the energy consumption and maintenance costs of the equipment.

[0026] like Figures 2-3 As shown, the device also includes: a partition plate 9 installed inside the body 1, which divides the interior of the body 1 into two non-communicating chambers, namely, a first chamber 10 for purifying natural gas and a second chamber 11 for containing absorbent liquid. The partition plate 9 is hollow and the venturi tube 5 is connected to the partition plate 9; and a gas guide pipe 12 installed on the partition plate 9, which is used to guide the gas flowing in the venturi tube 5 into the absorbent liquid.

[0027] Specifically, in the existing technology, carbon dioxide absorbent flows through the venturi tube 5. The flow rate of the absorbent is relatively fast, which leads to insufficient contact and reaction between the absorbent and carbon dioxide, resulting in low utilization. On the other hand, the absorbent is prone to vaporization during the flow process, which causes the humidity on the membrane module 2 side to gradually increase, thereby affecting the selective permeability of the membrane module 2 and reducing the overall separation efficiency. During operation, nitrogen gas is introduced into the venturi tube 5. The nitrogen gas, carrying carbon dioxide gas, is introduced into the carbon dioxide absorption liquid in the second chamber 11, where the carbon dioxide is absorbed by the carbon dioxide absorption liquid. The gas rises slowly in the absorbent in the form of bubbles, which greatly prolongs the contact time between carbon dioxide and absorbent and improves the problem of insufficient reaction caused by excessive flow rate in the prior art. This significantly improves the carbon dioxide absorption efficiency and absorbent utilization rate. At the same time, the absorbent is stored in a separate second chamber 11, which improves the problem of absorbent vaporization affecting the humidity of membrane module 2. The humidity on one side of membrane module 2 is stable, which ensures the selective permeability of membrane module 2 and ensures that the overall purification and separation effect is stable and reliable.

[0028] like Figure 3 and Figure 4 As shown, the diameter of the spiral shaft 8 gradually increases from top to bottom, and the throat size of the intake structure 6 decreases in a stepped manner from top to bottom.

[0029] Specifically, as the raw gas flows from top to bottom, carbon dioxide is continuously separated and discharged, causing the total gas volume to gradually decrease. Based on this separation characteristic, the diameter of the spiral shaft 8 is designed to gradually increase from top to bottom. This can compensate for the pressure loss caused by the decrease in the total gas volume through the adaptive contraction of the flow channel space, ensuring that the gas pressure remains stable throughout the flow process and avoiding the impact of pressure fluctuations on the separation effect. Meanwhile, the throat size of the intake structure 6 adopts a stepped reduction design from top to bottom. Combined with the hydrodynamic effect of the venturi tube 5, the lower throat has a smaller size and a higher nitrogen flow rate, forming a gradient pressure difference with weaker upper part and stronger lower part. This design is precisely matched with the separation process: the carbon dioxide content gradually decreases as the raw gas flows downward, while the stronger pressure difference below can provide sufficient driving force to effectively overcome the separation resistance of low-concentration carbon dioxide, avoid the problem of incomplete separation due to insufficient driving force in the later stage, and significantly improve the overall decarbonization purity of natural gas.

[0030] like Figures 1-4As shown, the device also includes: several connecting holes 13 on the body 1; a first annular plate 14 installed on the body 1, the first annular plate 14 containing an adsorbent desiccant, the first annular plate 14 being connected to a second chamber 11 through the connecting holes 13; a second annular plate 15 installed on the body 1, the second annular plate 15 containing a buffer chamber 16; several second pipes 17 for connecting the venturi tube 5 and the buffer chamber 16; and a circulation pump 18 installed between the second annular plate 15 and the first annular plate 14, the input end of the circulation pump 18 being connected to the first annular plate 14 and the output end being connected to the buffer chamber 16, for drying the gas in the second chamber 11 with the adsorbent desiccant and then re-introducing it into the venturi tube 5 for recycling.

[0031] Specifically, the nitrogen gas flowing out of the venturi tube 5 carries carbon dioxide into the absorbent in the second chamber 11. The carbon dioxide is fully adsorbed by the absorbent, and the remaining nitrogen gas enters the first annular plate 14 through the connecting hole 13. After being dried and cleaned by the internal adsorption desiccant, it re-enters the venturi tube 5 through the circulation pump 18, the buffer chamber 16 and the second tube 17 in sequence, forming a closed-loop circulation working mode of nitrogen gas. Nitrogen does not need to be consumed at once. After drying, it can be repeatedly introduced into the Venturi tube 5 to play a low-pressure driving role, which greatly reduces the amount of nitrogen replenishment and reduces the cost of gas consumables. Before the nitrogen is circulated, it is dried by an adsorption desiccant, which can completely remove the water vapor carried out from the absorbent. This prevents water vapor from entering the Venturi tube 5 with the nitrogen and affecting the humidity on the membrane module 2 side again, further ensuring the selective permeability of the membrane module 2 and maintaining stable separation efficiency.

[0032] like Figure 2 and Figure 6 As shown, a tubular sieve plate 19 is installed at the end of the gas guide pipe 12. The tubular sieve plate 19 divides the gas introduced into the absorbent liquid into tiny bubbles through several sieve holes on its pipe wall, so as to increase the contact area between the gas and the absorbent liquid.

[0033] The tubular sieve plate 19 is rotatably connected to the air guide pipe 12, and an impeller 20 is fixedly installed inside the tubular sieve plate 19.

[0034] Specifically, when the gas from the gas guide tube 12 enters the absorbent, it directly impacts the impeller 20 and drives it to rotate, which in turn drives the tubular sieve plate 19 to rotate synchronously. This achieves the synergistic effect of gas segmentation and rotational disturbance. The sieve holes of the tubular sieve plate 19 first segment the gas into tiny bubbles. During rotation, the bubbles are further dispersed, and the centrifugal force generated by the rotation causes the bubbles to diffuse evenly in the absorbent, avoiding local aggregation. This significantly increases the contact area between carbon dioxide and the absorbent, enhancing absorption efficiency. The rotational disturbance breaks the natural rising trajectory of the bubbles, prolonging the residence time of the bubbles in the absorbent and further improving the utilization rate of the absorbent.

[0035] like Figure 1 , Figure 2 and Figure 3 As shown, a check valve 21 is installed on both the feed pipe 3 and the discharge pipe 4. The check valve 21 is used to restrict the direction of gas flow.

[0036] Specifically, the first check valve 21 of the feed pipe 3 only allows raw gas to enter the machine body 1 from the outside, preventing treated or untreated gas inside the machine from flowing back to the gas supply system; the first check valve 21 of the first discharge pipe 4 only allows the target natural gas after decarbonization to be discharged, avoiding the backflow of discharged gas into the machine body 1. The two work together to prevent cross-flow of different gases, thoroughly ensuring the purity of natural gas after decarbonization and avoiding the decrease in purification effect caused by gas mixing. At the same time, the one-way flow restriction of the check valve can avoid the pressure cancellation caused by reverse gas flow, ensuring the stability of the feed pressure on the raw gas side, while ensuring that the low-pressure field constructed by the Venturi tube 5 is not disturbed, maintaining the continuous stability of the gas pressure difference on both sides of the membrane module 2, and providing a reliable driving force for efficient carbon dioxide separation.

[0037] like Figures 5-9 As shown, the device also includes: several holes 22 formed inside the spiral shaft 8, the spiral shaft 8 having a hollow structure, and the gas being discharged from the holes 22 and sprayed at an inclined angle with the membrane module 2; a cylinder 23 rotatably installed inside the spiral shaft 8, the cylinder 23 having holes 24; a connector 25 rotatably installed above the spiral shaft 8, the connector 25 communicating with the spiral shaft 8, the connector 25 being fixedly installed on the machine body 1, and a second air inlet pipe 26 installed on the connector 25; and a second discharge pipe 27 installed on the machine body 1, the second discharge pipe 27 passing through the partition plate 9 and communicating with the first chamber 10.

[0038] The device also includes: an exhaust pipe 28 installed on the body 1, a second one-way valve 29 installed on the exhaust pipe 28, and the exhaust pipe 28 communicating with the second chamber 11; a round rod 30 slidably installed on the spiral shaft 8, the round rod 30 being threadedly connected to the cylinder 23, the round rod 30 having a third hole 31, the third hole 31 communicating with the interior of the spiral shaft 8; and a torsion spring installed between the round rod 30 and the cylinder 23.

[0039] Specifically, in the initial state, hole 22 and hole 24 are separated, and the interior of the spiral shaft 8 is not connected to the outside. When membrane module 2 becomes clogged with impurities after prolonged use, the supply of feed gas can be stopped first. Then, clean nitrogen gas is introduced into the spiral shaft 8 through the second air inlet pipe 26. As the internal gas pressure increases, the circular rod 30 slides downward. During the downward sliding of the circular rod 30, the cylinder 23 rotates, aligning the first hole 22 and the second hole 24. This allows some clean nitrogen gas to be blown onto membrane module 2 at an angle downward through the first hole 22. During this process, the spiral shaft 8 is controlled to rotate rapidly, and the first hole 22 rotates synchronously with the spiral shaft 8, creating an angled downward airflow. The annular surface of the membrane module 2 can be covered. Combined with the high-speed rotating turbulent disturbance, it can directly impact the stubborn impurities on the membrane surface, quickly loosen and remove the blockages. During this process, the nitrogen carrying the impurities is discharged through the second discharge pipe 27, which is to purge and clean the membrane module 2. While the round rod 30 slides downward, the spiral shaft 8 can be connected to the space inside the partition plate 9 through the third hole 31, so that some clean nitrogen enters the second chamber 11, thereby increasing the gas pressure in the second chamber 11. The old nitrogen in the machine body 1 can be discharged from the exhaust pipe 28 with the second one-way valve 29, realizing the replacement of nitrogen.

[0040] like Figures 1-3 As shown, the device also includes: a buffer tank 32 installed on the periphery of the machine body 1; a first air inlet pipe 33 and an air outlet pipe 34 installed on the buffer tank 32, the first air inlet pipe 33 and the air outlet pipe 34 being connected to the first discharge pipe 4 and the second discharge pipe 27 respectively; and two electromagnetic three-way valves 35 installed on the first air inlet pipe 33 and the first discharge pipe 4 and the air outlet pipe 34 and the second discharge pipe 27 respectively.

[0041] Specifically, initially, the buffer tank 32 is under low pressure. During purging, the supply of raw material gas and the circulation of nitrogen are stopped. Then, the solenoid three-way valve 35 on the first discharge pipe 4 is controlled to change its connection state, connecting the first chamber 10 with the buffer tank 32. At this time, the pressure in the first chamber 10 is high, while the pressure in the buffer tank 32 is low. Therefore, the residual gas in the machine body 1 will enter the buffer tank 32 for storage. Then, the solenoid three-way valve 35 is controlled to change its connection state, preventing gas from being discharged from the first discharge pipe 4. The solenoid three-way valve 35 on the second discharge pipe 27 is controlled to change its connection state, allowing gas to flow out from there. Then, new nitrogen is introduced for purging. During purging, the gas carrying impurities flows out from the second discharge pipe 27. 7 (A pump body is installed on the second discharge pipe 27 to facilitate the complete discharge of nitrogen) After the purging is completed, the circulating pump 18 is started first, so that the first chamber 10 is in a low-pressure state. Then, the electromagnetic three-way valve 35 on the second discharge pipe 27 is changed to change the connection state, so that the buffer tank 32 is connected to the first chamber 10. The gas in the buffer tank 32 enters the first chamber 10 under the action of the gas pressure difference. Then, the electromagnetic three-way valve 35 on the second discharge pipe 27 is changed to change the connection state, so that the gas cannot be discharged from the second discharge pipe 27. At this time, the gas in the buffer tank 32 has been basically emptied and the initial low-pressure state is restored. Then, the electromagnetic three-way valve 35 on the first discharge pipe 4 is changed to change the connection state, and the raw material gas is supplied again. Before purging, the residual raw material gas in chamber 10 is first introduced into the low-pressure buffer tank 32 for storage, so as to avoid it being discharged with impurity gas during purging, reduce raw material waste, and conform to the concept of energy saving and optimization.

[0042] Working principle: Before operation, nitrogen gas is introduced into the venturi tube 5. The nitrogen gas creates low pressure as it flows through the throat. The feed pipe 3 is connected to the gas supply system. During operation, the feed gas is controlled to enter from the feed pipe 3 at the top of the machine body 1. After entering vertically from the feed pipe 3 at the top of the machine body 1, the feed gas flows spirally downwards along the inner circumference of the membrane module 2 under the guidance of the spiral shaft 8, maintaining a unidirectional trajectory throughout the process with no reverse flow. Due to the spiral downward flow of the feed gas, it fully contacts the membrane module 2. During this process, carbon dioxide in the feed gas undergoes low-pressure adsorption in the venturi tube 5. The nitrogen gas passes through the membrane module 2 and is drawn into the venturi tube 5. After the nitrogen gas carries carbon dioxide gas, it is introduced into the carbon dioxide absorption liquid in the second chamber 11. The carbon dioxide is absorbed by the carbon dioxide absorption liquid, and the remaining nitrogen gas enters the first annular plate 14 through the connection hole 13. After being dried and impurities removed by the internal adsorption desiccant, it passes through the circulation pump 18, the buffer chamber 16 and the second pipe 17 in sequence and re-enters the venturi tube 5, forming a closed-loop circulation working mode of nitrogen gas. The decarbonized target natural gas continues to flow downward along the predetermined flow channel and is discharged from the first discharge pipe 4, completing the efficient purification. During purging and cleaning, the supply of raw material gas and nitrogen circulation are stopped. Then, the electromagnetic three-way valve 35 on the first discharge pipe 4 is controlled to change its connection state, connecting the first chamber 10 to the buffer tank 32. At this time, the pressure in the first chamber 10 is high, and the pressure in the buffer tank 32 is low. Therefore, the residual gas in the machine body 1 will enter the buffer tank 32 for storage. Then, the electromagnetic three-way valve 35 is controlled to change its connection state, preventing gas from venting from the first discharge pipe 4. The electromagnetic three-way valve 35 on the second discharge pipe 27 is then controlled to change its connection state, allowing gas to flow out from there. Clean nitrogen is then introduced into the spiral shaft 8 through the second air inlet pipe 26. As the internal pressure increases, the circular rod 30 slides downward. During this downward sliding, the circular rod 30 drives the cylinder 23 to rotate, aligning the first hole 22 and the second hole 24. This allows some clean nitrogen to be blown onto the membrane module 2 at an angle downward through the first hole 22. During this process, the spiral shaft 8 is controlled to rotate rapidly, and the first hole 22 rotates synchronously with the spiral shaft 8. The downward airflow can cover the annular surface of the membrane module 2. Combined with the high-speed rotating turbulent disturbance, it can directly... Stubborn impurities on the membrane surface are quickly loosened and removed by the impactor. During this process, nitrogen carrying impurities is discharged through the second discharge pipe 27, thus purging and cleaning the membrane module 2. As the round rod 30 slides downward, the spiral shaft 8 can connect with the space inside the partition plate 9 through the third hole 31, allowing some clean nitrogen to enter the second chamber 11. This increases the air pressure in the second chamber 11, allowing the old nitrogen in the machine body 1 to be discharged through the exhaust pipe 28 with the second one-way valve 29, thus replacing the nitrogen. After purging, the circulating pump 18 is started first, causing the first... When chamber 10 is in a low-pressure state, the electromagnetic three-way valve 35 on the second discharge pipe 27 is controlled to change the connection state, so that the buffer tank 32 is connected to the first chamber 10. The gas in the buffer tank 32 enters the first chamber 10 under the action of the gas pressure difference. Then, the electromagnetic three-way valve 35 on the second discharge pipe 27 is controlled to change the connection state, so that the gas cannot be discharged from the second discharge pipe 27. At this time, the gas in the buffer tank 32 has been basically emptied, and the initial low-pressure state is restored. Then, the electromagnetic three-way valve 35 on the first discharge pipe 4 is controlled to change the connection state, and the raw material gas is supplied again.

[0043] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An energy-saving optimization device for a high-efficiency natural gas purification system using membrane separation, comprising a body (1) and a membrane module (2) for purifying natural gas, wherein the membrane module (2) includes a support and a separation membrane, and the body (1) is connected to an inlet pipe (3) and a first outlet pipe (4), characterized in that, Also includes: A Venturi tube (5) is installed inside the body (1). The Venturi tube (5) has multiple air intake structures (6) linearly distributed along the axis of the body (1). The air intake structure (6) consists of a constriction section, a throat, and a diffusion section. A gas inlet hole (7) is provided on the throat. The membrane assembly (2) and the Venturi tube (5) are both installed in a ring inside the body (1). The membrane assembly (2) is located inside the Venturi tube (5). Rotate the spiral shaft (8) installed inside the machine body (1). The spiral shaft (8) is located on the inner circumference of the membrane assembly (2). The feed pipe (3) is located above the machine body (1). The first discharge pipe (4) is located in the lower middle part of the machine body (1).

2. The energy-saving optimization device for a membrane separation high-efficiency natural gas purification system according to claim 1, characterized in that: The device also includes: A partition plate (9) is installed inside the body (1). The partition plate (9) divides the interior of the body (1) into a first chamber (10) and a second chamber (11) that are not connected to each other. The first chamber (10) is used to purify natural gas, and the second chamber (11) is used to contain absorbent liquid. The partition plate (9) is hollow, and the Venturi tube (5) is connected to the partition plate (9). A gas guide tube (12) is installed on the partition plate (9) to guide the gas flowing in the venturi tube (5) into the absorption liquid.

3. The energy-saving optimization device for a membrane separation high-efficiency natural gas purification system according to claim 1, characterized in that: The diameter of the spiral shaft (8) gradually increases from top to bottom, and the throat size of the air intake structure (6) decreases in a stepwise manner from top to bottom.

4. The energy-saving optimization device for a membrane separation high-efficiency natural gas purification system according to claim 2, characterized in that: The device also includes: Several connection holes (13) are provided on the body (1); An annular plate (14) is installed on the body (1), and an adsorbent desiccant is installed inside the annular plate (14). The annular plate (14) is connected to the second cavity (11) through the connecting hole (13). A second annular plate (15) is installed on the body (1), and a buffer cavity (16) is provided inside the second annular plate (15). Several second tubes (17) for connecting the Venturi tube (5) and the buffer cavity (16); A circulation pump (18) is installed between the second annular plate (15) and the first annular plate (14). The input end of the circulation pump (18) is connected to the first annular plate (14), and the output end is connected to the buffer chamber (16). It is used to dry the gas in the second chamber (11) with an adsorption desiccant and then reintroduce it into the Venturi tube (5) for recycling.

5. The energy-saving optimization device for a membrane separation high-efficiency natural gas purification system according to claim 2, characterized in that: The end of the gas guide tube (12) is equipped with a tubular sieve plate (19). The tubular sieve plate (19) divides the gas introduced into the absorbent liquid into tiny bubbles through several sieve holes on its tube wall, so as to increase the contact area between the gas and the absorbent liquid.

6. The energy-saving optimization device for a membrane separation high-efficiency natural gas purification system according to claim 5, characterized in that: The tubular sieve plate (19) is rotatably connected to the air guide pipe (12), and an impeller (20) is fixedly installed inside the tubular sieve plate (19).

7. The energy-saving optimization device for a membrane separation high-efficiency natural gas purification system according to claim 4, characterized in that: A check valve (21) is installed on both the feed pipe (3) and the discharge pipe (4). The check valve (21) is used to restrict the direction of gas flow.

8. The energy-saving optimization device for a membrane separation high-efficiency natural gas purification system according to claim 7, characterized in that: The device also includes: Several holes (22) are opened inside the spiral shaft (8). The spiral shaft (8) has a hollow structure. After the gas is discharged from the holes (22), it is sprayed at an inclined angle to the membrane module (2). A cylinder (23) is rotatably installed inside the spiral shaft (8), and a second hole (24) is provided on the cylinder (23). A connecting piece (25) is rotatably installed above the spiral shaft (8). The connecting piece (25) is connected to the spiral shaft (8). The connecting piece (25) is fixedly installed on the body (1). A second air intake pipe (26) is installed on the connecting piece (25). The No. 2 discharge pipe (27) is installed on the machine body (1), and the No. 2 discharge pipe (27) passes through the partition plate (9) and is connected to the No. 1 cavity (10).

9. The energy-saving optimization device for a membrane separation high-efficiency natural gas purification system according to claim 8, characterized in that: The device also includes: An exhaust pipe (28) is installed on the body (1), and a second one-way valve (29) is provided on the exhaust pipe (28). The exhaust pipe (28) is connected to the second chamber (11). A round rod (30) is slidably mounted on the spiral shaft (8). The round rod (30) is threadedly connected to the cylinder (23). A third hole (31) is provided on the round rod (30). The third hole (31) is connected to the interior of the spiral shaft (8). A torsion spring is installed between the rod (30) and the cylinder (23).

10. The energy-saving optimization device for a membrane separation high-efficiency natural gas purification system according to claim 8, characterized in that: The device also includes: A buffer tank (32) is installed on the periphery of the body (1); The first air inlet pipe (33) and the air outlet pipe (34) are installed on the buffer tank (32), and the first air inlet pipe (33) and the air outlet pipe (34) are respectively connected to the first discharge pipe (4) and the second discharge pipe (27); Two electromagnetic three-way valves (35) are respectively installed on the first air inlet pipe (33) and the first discharge pipe (4) and the air outlet pipe (34) and the second discharge pipe (27).

Images