Multi-stage purification low-energy-consumption natural gas helium extraction pretreatment device

Abstract

The invention discloses a multistage-purification low-energy-consumption natural gas helium extraction pretreatment device, and relates to the technical field of helium extraction. The device comprises double barrel bodies which are internally and externally nested, and a flow dividing pipe assembly, a spiral flow guide belt, a spoiler, a liquid baffle and a liquid catching barrel which are integrated on the double barrel bodies. The shunting pipe assembly is used for shunting raw material gas into cold gas flow and hot gas flow by utilizing an eddy current effect; the hot air flow is used for strengthening gas-liquid separation, and the cold air flow is used for recycling cold energy and recycling. Airflow is subjected to multi-stage rotational flow, collision and trapping in an annular space of the double cylinders, and finally deep purification is achieved. According to the invention, vortex energy separation, multi-stage gas-liquid separation and energy recovery are integrated, external cold and heat sources are not needed, the system energy consumption is remarkably reduced while heavy hydrocarbon and liquid drops are efficiently removed, and clean feed gas is provided for subsequent helium extraction.

Description

A multi-stage purification, low-energy natural gas helium extraction pretreatment device Technical Field

[0001] This invention relates to the field of helium extraction technology, and in particular to a low-energy-consumption natural gas helium extraction pretreatment device with multi-stage purification. Background Technology

[0002] Helium, a scarce strategic resource, is widely used in high-tech fields such as aerospace, semiconductor manufacturing, medical equipment, and scientific research. Global helium reserves are limited and unevenly distributed, with natural gas being the primary source for industrial helium extraction. Currently, the most common helium extraction process in China is the cryogenic method. This involves using cryogenic equipment to initially separate methane from helium during natural gas liquefaction and BOG (bottom gas vapor) from LNG vaporization, or using distillation columns for preliminary purification. Further purification is then achieved through dehydrogenation, dehydration, and impurity removal using tower and reactor equipment, followed by cryogenic liquefaction in a cold box at extremely low temperatures to extract liquid helium. The core of this process is the use of cryogenic temperatures to separate helium from natural gas; this cryogenic environment is crucial for the equipment. The requirements are stringent, resulting in high equipment and energy costs. BOG feed gas has a complex composition, containing heavy hydrocarbons such as ethane and propane in addition to methane and helium, as well as moisture and solid impurities. These impurities condense or solidify at low temperatures. If they are not adequately pretreated and removed before entering the cryogenic equipment, they may freeze or wax on the pipes and heat exchanger surfaces, causing blockages, frequent equipment downtime for maintenance, and low production efficiency. Furthermore, ethane or higher condensable hydrocarbons are particularly harmful to subsequent membrane separation processes, causing membrane pore blockage, membrane material swelling and plasticization, decreased separation performance, and even permanent damage. Therefore, the cleanliness of BOG feed gas directly affects the stable operation of subsequent cryogenic concentration and membrane separation equipment, as well as helium extraction efficiency.

[0003] Existing BOG feedstock gas contains ethane or more condensable hydrocarbon components due to differences in gas fields. These condensed components are prone to freezing and clogging pipelines in low-temperature concentration equipment, and may also cause membrane pore blockage in membrane separators. In severe cases, the membrane material may swell and plasticize, destroying selectivity, which will lead to a sharp decline in gas flux and separation efficiency, and a shortened membrane module life.

[0004] Chinese patent document (publication number: CN118816482B) discloses a natural gas helium extraction device and a natural gas helium extraction method. While the aforementioned device and method can significantly reduce safety risks and effectively lower equipment costs, they do not provide an optimal solution for the pretreatment of raw gas, especially for the efficient and low-energy removal of condensable hydrocarbons. Traditional pretreatment methods often rely on external heating or refrigeration devices to achieve gas-liquid separation, resulting in high energy consumption and increased operating costs. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a low-energy-consumption pretreatment device for helium extraction from natural gas, featuring multi-stage purification. It employs a concentric double-cylinder structure integrating a diversion pipe assembly, a spiral guide belt, baffles and liquid baffles, and a liquid trap to form a progressive multi-stage purification system. The diversion pipe assembly utilizes the eddy current energy separation effect to split a single BOG gas source into two streams, one hot and one cold. The heated stream converts heavy hydrocarbons into a liquid state for easy discharge, while the cooled stream recovers liquid ethane or other condensable hydrocarbons for cold energy recycling. This achieves energy recovery without the need for external heating or refrigeration devices. The system utilizes a tiered approach; high-speed rotation within the vortex chamber generates a centrifugal force field to achieve initial separation of droplets. The baffle plate forces the airflow in an S-shaped radial motion, which, together with the baffle plate, forms a multi-stage separation unit of flow guidance, collision, and capture. The liquid-capturing cylinder intercepts residual fine droplets through a combination of centrifugal separation via an arched groove, enhanced capture via a serrated outward protrusion, and rapid liquid discharge via a flow guide groove. This creates a separation system that combines coarse and fine droplets for different particle sizes, achieving highly efficient gas-liquid separation and deep gas purification while significantly reducing energy consumption. This ensures that the discharged gas meets the cleanliness requirements for low-temperature concentration and membrane separation.

[0006] This invention is achieved using the following technical solution: a multi-stage purification low-energy natural gas helium extraction pretreatment device, characterized in that the pretreatment mechanism includes a second cylinder and a first cylinder nested together, with an annular space between the two cylinders; a diversion pipe assembly is fixedly mounted on the first cylinder, the diversion pipe assembly including an input port, a first output port and a second output port, the first output port penetrating the first cylinder and extending into the annular space, a spiral guide band on the inner wall of the first cylinder, and baffles spaced circumferentially inside the annular space above the first output port; a liquid trapping cylinder is installed at the connection point at the top of the two cylinders, the liquid trapping cylinder being connected to the top of the first cylinder.

[0007] Furthermore, the baffle is an arc-shaped plate, with one end fixed to the inner or outer cylinder and the other end gradually extending radially toward the opposite cylinder. There is a radial distance between the inner and outer cylinders to form a fluid channel, and the baffle has a smooth arc-shaped guide surface. Both the baffle and the inner wall of the first cylinder in the same radial direction are equipped with baffles, which are installed at intervals along the circumferential direction and alternately arranged on both sides of the annular space.

[0008] Furthermore, the liquid baffle has a T-shaped plate structure, including a longitudinal plate and a transverse plate. The two ends of the transverse plate of the liquid baffle extend toward the longitudinal plate to form lugs. Multiple serrated strips are fixed on the transverse plate between the lugs and the longitudinal plate, and liquid-guiding grooves are formed between adjacent serrated strips along the length of the longitudinal plate. Several through grooves are opened along the length of the longitudinal plate, and dog teeth are fixed at the openings of the through grooves. The dog teeth form staggered channels on both sides of the openings of the through grooves, and are recessed along the length of the through grooves to form liquid-guiding grooves. Both the liquid-guiding grooves and the liquid-guiding grooves guide the accumulated droplets to the bottom of the baffle.

[0009] Furthermore, the bottom of the baffle extends outward to form a tray, which is a hollow cavity structure. The bottom end of the baffle extends into the tray cavity. The liquid guiding groove and the liquid guiding groove are connected to the cavity of the tray. A guide pipe is provided in the cavity of the tray, and the other end of the guide pipe extends to the internal accommodating space of the second cylinder. A second tray is provided at the bottom of the baffle located on the inner wall of the first cylinder. The second tray is a hollow cavity structure. The liquid guiding groove and the liquid guiding groove of the baffle located on the inner wall of the first cylinder are connected to the cavity of the second tray. A guide channel is formed inside the cylinder wall of the first cylinder. One end of the guide channel is connected to the cavity of the second tray, and the other end of the guide channel extends to the bottom of the first cylinder and is connected to the internal accommodating space of the cylinder.

[0010] Furthermore, the bottom end of the second cylinder is through-connected and fixedly installed inside the bottom of the first cylinder, the bottom of the second cylinder is provided with an opening communicating with the accommodating space of the first cylinder, and the bottom end of the first cylinder is provided with a liquid outlet valve.

[0011] Furthermore, the tops of both the second and first cylinders are conical inclined structures with openings at the top. The liquid-catching cylinder is connected between the two top openings of the second and first cylinders. A guide ring is provided on the outer periphery of the bottom of the liquid-catching cylinder, and the guide ring is fixedly connected to the second cylinder. The liquid-catching cylinder includes a third cylinder. Several guide grooves are axially spaced on the outer periphery of the third cylinder. Several arched grooves are provided between two adjacent guide grooves. An air outlet is provided through the third cylinder wall at the top of the arched groove. A serrated protrusion is provided on the arched groove in front of the air outlet.

[0012] Furthermore, a coalescing component is provided outside the first output port, and the coalescing component is fixedly installed between the two cylinders. The coalescing component is a wire mesh, a honeycomb structure, or a ceramic ring.

[0013] Furthermore, the diverter assembly also includes a sleeve, the input port being provided on the side of the sleeve, and protrusions fixed at both ends of the sleeve's interior. A tube body is fixedly inserted inside the protrusions, and the two ends of the tube body extend away from the protrusions to form a first output port with a long tube structure and a second output port with a short tube structure. A cone is fixed at the end of the first output port, the cone being located inside the first output port, and the diameter of the bottom surface of the cone being smaller than the inner diameter of the first output port. Several air distribution holes are provided on the tube body between the two protrusions. A conical opening is provided at the inner end of the second output port, the smaller end of the conical opening being close to the protrusion. A vortex tube is fixedly sleeved inside the tube body located between the two protrusions. The vortex tube has a cylindrical structure, and several vortex grooves are arrayed on one end of the vortex tube near the cone. The outer diameter of the tube located on the outer periphery of the vortex grooves is smaller than the outer diameter of the vortex tube.

[0014] Furthermore, a booster is provided on the outside of the first cylinder, and a heat exchange tube is connected to the end of the second output port. The heat exchange tube is sealed and passes through the inside of the first and second cylinders and is coiled. The other end of the heat exchange tube passes through the outside of the two cylinders and is connected to the input end of the booster. The output end of the booster is connected to the input port through a tee.

[0015] Furthermore, the spiral guide band is fixedly installed on the inner wall of the first cylinder to guide the airflow to rotate upward along the axial direction.

[0016] The multi-stage purification low-energy-consumption natural gas helium extraction pretreatment device of the present invention has the following beneficial effects: 1. The present invention sets up a pretreatment mechanism at the front end of the primary concentration mechanism, which undertakes the key task of removing ethane or more condensable hydrocarbons from the BOG feed gas, reducing the risk of ethane or more condensable hydrocarbons freezing and clogging pipelines in the low-temperature concentration equipment, or ethane or more condensable hydrocarbons causing membrane pore blockage in the membrane separator, or membrane material swelling and plasticization; the pretreatment mechanism adopts a double-cylinder concentric structure, and from bottom to top, it undergoes progressive multi-stage purification of pre-separation and hot and cold flow separation by the diversion pipe assembly, spiral guide belt swirl separation, collision separation by the baffle plate and the liquid baffle, and fine separation by the liquid trapping cylinder; the diversion pipe assembly uses the eddy current energy separation effect to split the single BOG gas source into two gas streams of heating and cooling, and the heating gas stream removes solid or near-freezing point heavy hydrocarbons. Hydrocarbons are transformed into a liquid state, enhancing fluidity for continuous discharge. The cooled airflow exchanges heat with the liquid ethane or other condensable hydrocarbons at the bottom of the cylinder, stabilizing the liquid phase and suppressing volatilization. The gas is then recycled by a booster compressor, achieving energy cascade utilization without the need for external heating or refrigeration devices. More notably, the swirling flow inside the diversion pipe achieves preliminary separation of droplets. The baffle plate forces the airflow into a composite swirling field with S-shaped radial movement. The baffle plate and the baffle plate work together to form a multi-stage separation unit of flow guidance, collision, and capture, achieving multiple collision-coalescence cycles to improve the removal capacity of fine droplets. The device innovatively integrates eddy energy separation, hot and cold airflow diversion, multi-stage gas-liquid separation, energy recovery and circulation, and a compact double-cylinder structure into an integrated pretreatment system. While achieving efficient gas-liquid separation and deep gas purification, it significantly reduces energy consumption and improves the cleanliness of the discharged gas.

[0017] 2. In this invention, the BOG enters the cyclone separator through the input port of the splitter assembly. The airflow enters the tube at high speed along the tangential direction, forming a vortex chamber. After rotating at high speed within the vortex chamber, it separates into two airflows with unequal total temperatures. The low-temperature airflow located at the center of the vortex chamber is discharged through the second output port, while the high-temperature airflow located on the outer layer is discharged through the first output port. This invention provides both a heating airflow to enhance the gas-liquid separation process and a cooling airflow to stabilize the liquid phase after separation, without the need for external heating or cooling devices. The heating airflow transforms heavy hydrocarbons from a solid or near-freezing point state into a liquid state, enhancing their fluidity and facilitating collection and discharge. The warm airflow recovers the cold energy of liquid ethane or condensable hydrocarbons and recycles it to avoid energy waste. More importantly, the airflow generates a strong centrifugal force field when it rotates at high speed in the vortex chamber. The droplets carried in the airflow are thrown towards the outer wall of the vortex chamber under the action of centrifugal force to achieve preliminary gas-liquid separation. Larger droplets directly hit the inner wall of the tube and merge before being discharged along the wall surface. Smaller droplets are discharged from the first output port with the high-temperature outer airflow and then enter the spiral guide zone and baffle area for secondary separation. The diversion tube assembly not only realizes the separation of hot and cold airflow, but also has a pre-separation function, which reduces the load on subsequent multi-stage separation and improves the overall separation efficiency.

[0018] 3. In this invention, the baffle forces the airflow to move radially in an S-shape within the annular space, extending the airflow path and increasing the residence time. The arc-shaped surface guides the airflow to maintain tangential velocity during radial movement, forming an axial vortex and creating a composite vortex field to enhance the centrifugal separation effect. The baffle and the baffle work together to form a multi-stage separation unit of flow guidance, collision, and capture. When the airflow changes direction after passing the baffle, the droplets directly collide with the baffle due to inertia. The serrated strip increases the roughness of the collision surface, enhancing droplet capture and aggregation. The liquid inlet and the liquid guide work together to guide and collect the droplets, forming a complete liquid recovery channel of capture, convergence, flow guidance, and discharge. The alternating internal and external flow guidance achieves multiple collision-aggregation cycles, significantly improving the removal capacity of fine droplets.

[0019] 4. The liquid trapping cylinder in this invention serves as the final stage of droplet collection, intercepting residual fine droplets in the airflow. After entering from the bottom of the arched groove, the airflow rises along the arched trajectory, generating centrifugal motion. The droplets are captured due to inertial impact against the inner wall of the arched groove. The outlet is designed so that the airflow needs to change direction after passing through the arched groove to be discharged, further enhancing the inertial collision separation effect. The serrated outward protrusion increases the collision contact area, causing the airflow to generate micro-vortices and turbulence, enhancing the capture and aggregation of fine droplets. The centrifugal separation of the arched groove, the enhanced capture by the serrated outward protrusion, and the rapid discharge of the guide groove work together. The aggregated droplets flow into the guide groove through the bottom of the arched groove and are quickly discharged. The conical inclined surface causes the airflow to contract and slow down, promoting droplet settling and synergistic enhancement with the capture of the arched groove, ensuring that the discharged gas reaches the expected cleanliness, providing clean raw material gas that meets the requirements of low-temperature concentration and membrane separation for subsequent helium extraction. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1 is a schematic diagram of the overall installation structure of the pretreatment mechanism of the present invention; Figure 2 is a three-dimensional schematic diagram of the internal structure of the pretreatment mechanism of the present invention; Figure 3 is a top view of the internal structure of the pretreatment mechanism of the present invention; Figure 4 is a schematic diagram of the installation structure of the baffle and the liquid baffle of the present invention; Figure 5 is a three-dimensional schematic diagram of the cross-sectional structure of the liquid baffle of the present invention; Figure 6 is a three-dimensional schematic diagram of the liquid trapping cylinder structure of the present invention; Figure 7 is a cross-sectional schematic diagram of the disassembled structure of the diversion pipe assembly of the present invention; In the figures, 27-first cylinder, 28-first output port, 29-sleeve, 30-second output port, 31-output... 32-Inlet port, 33-Booster, 34-Outlet end, 35-Heat exchange tube, 36-Coalescing component, 37-Second cylinder, 38-Spiral guide belt, 39-Break plate, 40-Outlet, 41-Liquid trap, 42-Liquid baffle, 43-Longitudinal plate, 44-Drooping lug, 45-Through groove, 46-Tray, 47-Guide pipe, 48-Liquid guide groove, 49-Dog tooth, 50-Serrated strip, 51-Guide groove, 52-Arch groove, 53-Outlet, 54-Protrusion, 55-Gas distribution hole, 56-Cone, 57-Swirl cylinder, 58-Swirl groove. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention. Embodiments

[0024] As shown in Figures 1-7, a multi-stage purification, low-energy-consumption natural gas helium extraction pretreatment device includes a primary enrichment mechanism, a dehydrogenation and dehydration mechanism, a secondary enrichment mechanism, and a final purification mechanism connected by pipelines. A pretreatment mechanism is connected in series at the front end of the input pipe of the primary enrichment mechanism. The pretreatment mechanism includes a second cylinder 36 and a first cylinder 27 nested together, with an annular space between the two cylinders. A diverter assembly is fixed on the first cylinder 27, including an input port 31, a first output port 28, and a second output port 30. The first output port 28 extends through the first cylinder 27 into the annular space. A spiral guide band 37 is provided on the inner wall of the first cylinder 27. The annular space above the first output port 28 is equipped with a spiral guide band 37 spaced circumferentially. A baffle plate 38 is provided; a liquid trap 41 is installed at the connection between the tops of the two cylinders, and the liquid trap 41 is connected to the gas outlet 39 at the top of the first cylinder 27; In this invention, the pretreatment mechanism set at the front end of the primary concentration mechanism undertakes the key task of removing liquid ethane or more condensable hydrocarbons, solid impurities and moisture from the BOG feed gas, preventing liquid and solid substances from freezing and clogging the pipeline in the low temperature concentration equipment, reducing the negative impacts of ethane or more condensable hydrocarbons on the membrane separator such as membrane pore blockage, increased mass transfer resistance due to liquid film coverage on the membrane surface, swelling and plasticization of the membrane material damaging selectivity, and deformation and expansion of the membrane pore structure leading to a decrease in the separation coefficient, which leads to a sharp decrease in gas flux and separation efficiency and a shortened membrane module life. It is the first line of defense to ensure the safe operation of the entire helium extraction system.

[0025] Furthermore, the baffle 38 is an arc-shaped plate, with one end fixed to the inner or outer cylinder, and the other end gradually extending radially towards the opposite cylinder. A radial distance exists between the inner and outer cylinders to form a fluid channel, and the baffle 38 forms a smooth arc-shaped guiding surface. Both the baffle 38 and the inner wall of the first cylinder 27 in the same radial direction are equipped with baffles 42, which are spaced apart circumferentially and alternately arranged on both sides of the annular space. The baffle 38 is alternately fixed circumferentially to the outer wall of the inner cylinder and the inner wall of the outer cylinder. On the wall, the airflow is alternately guided from the outer circle to the inner circle of the annular space and then from the inner circle to the outer circle, changing its direction. Baffles 38 are alternately fixed to the inner and outer cylinders along the circumference, forcing the airflow to move radially in an "S" shape within the annular space, extending the airflow path, increasing residence time, and effectively preventing the airflow from "short-circuiting" and rushing directly from the bottom to the top. Simultaneously, the arc-shaped surface guides the airflow to maintain tangential velocity during radial movement, forming a composite swirling flow field combining axial swirling and radial reciprocating flow, enhancing the centrifugal separation effect. The smooth surface facilitates droplet coalescence and... The alternating internal and external flow guides achieve multiple collision-coalescence cycles, improving the removal capacity of fine droplets; the forced airflow at different radii causes periodic changes in centrifugal force, with large droplets being thrown towards the outer wall in the high centrifugal force zone of the outer ring, and droplets gaining sufficient settling time in the low-speed zone of the inner ring; in terms of liquid collection, the smooth arc-shaped surface facilitates the formation of a continuous liquid film, which flows naturally down the arc surface under gravity, preventing droplets from being re-atomized and carried out; the baffle plate 42 is installed on the baffle plate 38 and the inner wall of the cylinder in the same radial direction, and is spaced along the circumference. Furthermore, the baffles are arranged alternately on the inner and outer sides of the annular space to intercept and capture droplets. When the airflow changes direction by passing the baffle 38, the droplets deviate from the streamline due to inertia and directly collide with the baffle 42 to achieve gas-liquid separation. Small droplets collide, adhere, and coalesce into larger droplets on the surface. The baffle 42 and the baffle 38 work together. The baffle 38 guides the airflow to move alternately in the inner and outer rings and directs the airflow to the baffle 42. The baffle 42 intercepts droplets at the point where the airflow turns. Together, they constitute a multi-stage separation unit of "guide-collision-capture".

[0026] Furthermore, the liquid-blocking plate 42 has a T-shaped plate structure, including a longitudinal plate 43 and a transverse plate. The two ends of the transverse plate of the liquid-blocking plate 42 extend toward the longitudinal plate to form lugs 44. Multiple serrated strips 50 are fixed on the transverse plate between the lugs 44 and the longitudinal plate 43, and liquid-guiding grooves are formed between adjacent serrated strips 50 along the length direction of the longitudinal plate 43. Several through slots 45 are opened on the longitudinal plate 43 along the length direction. Dog teeth 49 are fixed at the openings of the through slots 45 respectively. The dog teeth 49 form staggered channels on both sides of the opening of the through slots and are recessed along the length direction in the through slots 45. A liquid guiding groove 48 is formed; both the liquid guiding groove 48 and the liquid guiding groove guide the collected droplets to the bottom of the baffle 38; it should be noted that the longitudinal plate 43 of the baffle 42 is set perpendicular to the airflow direction to intercept and collide droplets, and the horizontal plate is perpendicularly connected to the longitudinal plate 43 to enhance the structural strength and expand the droplet collection area; the lugs 44 formed by extending from both ends of the horizontal plate towards the longitudinal plate 43 play the role of lateral liquid blocking and droplet collection, converging the dispersed droplets on the horizontal plate towards the center and preventing droplets from overflowing from the two sides of the baffle 42, ensuring that the droplets are effectively collected; fixed on the horizontal plate The multiple serrated strips 50 increase the gas-liquid contact area and the roughness of the collision surface, enhancing the droplet capture and aggregation effect. The liquid guide groove formed between adjacent serrated strips 50 guides and gathers the collision-aggregated droplets along the length of the longitudinal plate 43, preventing droplets from dispersing and remaining on the surface of the transverse plate. The through-slots 45 opened on the longitudinal plate 43 allow some airflow to pass through, reducing the resistance of the baffle plate 42 to the airflow and the system pressure drop. The dog teeth 49 fixed at the opening of the through-slots 45 are located on both sides to form a staggered channel, causing secondary turbulence and collisions when the airflow passes through, further capturing the droplets in the airflow. The fine droplets carried by the liquid are quickly guided to the bottom by the liquid guiding groove 48 formed by the indentation along the length direction in the through groove 45, preventing the droplets from accumulating too much on the surface of the longitudinal plate 43 and being blown away again by the airflow. The liquid guiding groove and the liquid guiding groove 48 work together to guide the droplets collected on the horizontal plate and the longitudinal plate 43 to the bottom of the baffle plate 38. The droplets flow down along the arc surface of the baffle plate 38 and converge to the bottom of the device for discharge, forming a complete "capture-convergence-guidance-discharge" liquid recovery channel, avoiding secondary entrainment and improving droplet separation efficiency and liquid recovery rate.

[0027] Furthermore, the bottom of the baffle 38 extends outward to form a tray 46, which is a hollow cavity structure. The bottom end of the baffle 42 extends into the cavity of the tray 46. The liquid guide groove 48 and the liquid inlet groove are connected to the cavity of the tray 46. A guide pipe 47 is provided in the cavity of the tray 46, and the other end of the guide pipe 47 extends into the internal accommodating space of the second cylinder 36. A second tray is provided at the bottom of the baffle 42 located on the inner wall of the first cylinder 27. The second tray is a hollow cavity structure. The liquid guide groove 48 and liquid inlet groove of the liquid plate 42 are connected to the cavity of the second tray, forming a flow channel inside the cylinder wall of the first cylinder 27. One end of the flow channel is connected to the cavity of the second tray, and the other end of the flow channel extends to the bottom of the first cylinder 27 and is connected to the internal accommodating space of the cylinder. It should be noted that the tray 46 formed by the bottom of the baffle 38 extending outward is a hollow cavity structure, used to receive and collect the liquid droplets guided down from the liquid baffle 42. The bottom end of the liquid baffle 42 extends directly into the cavity of the tray 46. The liquid guide groove 48... 8 and the liquid inlet trough are connected to the cavity of tray 46, so that the liquid droplets collected by the baffle plate 42 can directly flow into the cavity of tray 46, avoiding secondary entrainment caused by the rising airflow during the droplet falling; the guide tube 47 set in the cavity of tray 46 guides the collected liquid out of the annular space, and the other end of the guide tube 47 extends into the internal accommodating space of the second cylinder 36 to achieve liquid concentration; for the baffle plate 42 located on the inner wall of the first cylinder 27, the second tray set at its bottom is also a hollow cavity structure to receive the baffle plate 42 on this side. The droplets collected by the liquid guide trough 48 and the liquid inlet trough are connected to the flow channel formed inside the second tray cavity and the first cylinder 27. The other end of the flow channel extends to the bottom of the first cylinder 27 and is connected to the internal accommodating space of the cylinder, guiding the collected liquid to the bottom. The droplets collected by the baffles 42 on both sides of the annular space can be collected in time through their respective trays 46 or the second tray and the flow channel system, avoiding liquid stagnation or accumulation in the separation area, keeping the airflow channel unobstructed, improving separation efficiency and equipment operation stability.

[0028] Furthermore, the bottom end of the second cylinder 36 is through-connected and fixedly installed inside the bottom of the first cylinder 27. The bottom of the second cylinder 36 has an opening that communicates with the accommodating space of the first cylinder 27, and the bottom end of the first cylinder 27 is provided with a liquid outlet valve. It should be noted that the bottom end of the second cylinder 36 is through-connected and fixedly installed inside the bottom of the first cylinder 27, realizing the structural connection and spatial communication of the liquid collection systems of the two cylinders. The outer wall of the second cylinder 36 and the inner wall of the first cylinder 27 together define an annular channel space. A baffle plate 38 and a baffle plate 42 are provided in the annular space to realize gas-liquid swirling separation. At the same time, the internal accommodating space of the second cylinder 36 serves as a liquid collection and guiding channel, so that the second cylinder 36 structurally undertakes the dual functions of defining the gas-liquid separation space and collecting and discharging liquid, realizing a multi-functional integrated design of one component.

[0029] Furthermore, the tops of both the second cylinder 36 and the first cylinder 27 are conical inclined structures, and each has an opening at its top. A liquid-catching cylinder 41 is connected between the two top openings of the second cylinder 36 and the first cylinder 27. A guide ring 40 is provided on the outer periphery of the bottom of the liquid-catching cylinder 41, and the guide ring 40 is fixedly connected to the second cylinder 36. The liquid-catching cylinder 41 includes a third cylinder, and several guide grooves 51 are axially spaced on the outer periphery of the third cylinder. Several arched grooves 52 are provided between two adjacent guide grooves 51. An air outlet 53 is provided through the third cylinder wall at the top of the arched groove 52. The arched groove 52 is provided with serrated protrusions; it should be noted that the inclined surface of the cone causes the airflow to gradually contract and decelerate during the upward process, promoting the sedimentation of droplets under the action of gravity and centrifugal force. At the same time, the droplets attached to the cone surface slide down the inclined surface and flow back to the lower separation area; the liquid-catching cylinder 41 connected between the two top openings of the second cylinder 36 and the first cylinder 27 serves as the last-stage droplet collection device, intercepting and separating the small droplets remaining in the airflow, reducing the number of droplets escaping from the top of the device with the airflow; the guide ring 40 provided on the outer periphery of the bottom of the liquid-catching cylinder 41 is fixedly connected to the second cylinder 36, receiving and collecting the droplets from the liquid-catching cylinder 41. The droplets separated from the inner wall are collected and guided into the second cylinder 36 to prevent them from being re-engaged by the airflow. Droplets collected on the outer wall of the third cylinder 41 are quickly guided to the bottom guide ring 40 to prevent accumulation on the cylinder wall. Several arched grooves 52 between adjacent guide grooves 51 provide a path for the airflow. The airflow enters from the bottom of the arched grooves 52 and rises along the arched trajectory, generating centrifugal motion under the arc guidance of the arched grooves 52. Droplets are captured by impacting the inner wall of the arched grooves 52 due to inertia, achieving gas-liquid separation. A through-hole is opened on the third cylinder wall at the top of the arched grooves 52. The vent 53 allows gas to escape. The vent 53 is designed so that the airflow needs to change direction after passing through the arched groove 52 before it can be discharged from the vent 53, which further enhances the inertial collision separation effect. The serrated protrusion on the arched groove 52 located in front of the vent 53 increases the gas-liquid collision contact area and surface roughness, causing the airflow to generate micro-vortices and turbulence when passing through the arched groove 52, which enhances the capture and aggregation of small droplets. The serrated protrusion promotes the adhesion and aggregation of droplets into larger droplets, which then flow into the guide groove 51 through the bottom of the arched groove 52 and are quickly discharged into the interior of the second cylinder 36 along the guide groove 51.

[0030] Furthermore, a coalescing component 35 is provided outside the first output port 28. The coalescing component 35 is fixedly installed between the two cylinders. The coalescing component 35 is a wire mesh, honeycomb structure or ceramic ring. The coalescing component 35 is mainly used to coalesce the droplets separated by the high-speed rotation of the airflow inside the coalescing splitter assembly, and the coalesced droplets fall to the bottom of the cylinder for storage.

[0031] Furthermore, the diverter assembly also includes a sleeve 29, with an input port 31 on its side. Protrusions 54 are fixed at both ends of the sleeve 29, and a tube body is fixedly inserted inside each protrusion 54. The two ends of the tube body extend away from the protrusions 54 to form a first output port 28 (long tube structure) and a second output port 30 (short tube structure). A cone 56 is fixed at the end of the first output port 28, located inside the first output port 28, with the bottom diameter of the cone 56 smaller than the inner diameter of the first output port 28. Several air distribution holes 55 are provided on the tube body between the two protrusions 54. A tapered opening is provided at the inner end of the second output port 30, with the smaller end of the tapered opening close to the protrusion. A vortex tube 57 is fixedly sleeved inside the tube body located between the two protrusions 54. The vortex tube 57 is a cylindrical structure. Several vortex grooves 58 are arrayed on one end of the vortex tube 57 near the cone 56. The outer diameter of the tube located around the vortex grooves 58 is smaller than the outer diameter of the vortex tube 57. It should be noted that there are 6 vortex grooves 58 and 5 air distribution holes 55. When airflow is introduced from the input port 31 and passes through the 5 air distribution holes 55, it enters its corresponding vortex groove 58. The airflow within the 5 vortex grooves 58 can rotate around the center and is finally discharged through the 6th vortex groove 58. After being guided by the vortex grooves 58, the airflow rotates at high speed along the first output port 28 and moves towards the pipe opening. Some airflow collides with the cone 56, bounces back, and moves towards the second output port 30 and is discharged. Some airflow is discharged from the gap between the cone 56 and the tube. The first output port 28 discharges heated airflow, and the second output port 30 discharges cooled airflow. The BOG of this invention enters the vortex tube 57 through the input port 31 and the sleeve 29. The airflow discharged from the vortex tube 57 enters the tube body at high speed along the tangential direction to form a vortex chamber. During high-speed rotation within the vortex chamber, the airflow undergoes vortex transformation and is separated into two parts with unequal total temperatures. One part of the airflow is located in the center of the vortex chamber, with a lower temperature, while the airflow in the outer layer has a higher temperature. The higher-temperature airflow is discharged through the first output port 28, and the lower-temperature airflow is discharged through the second output port 30, thus splitting the compressed air into two streams of hot and cold air. The heated airflow, split by the splitter assembly, enters through the first output port 28. Within the annular space of the cylinder, the gas flow from the first output port 28 is heated, causing the heavy hydrocarbons in the BOG that were originally in a solid or near-freezing point to transform into a liquid state. This enhances the fluidity and coalescence of the droplets, facilitating separation by swirl. The gas flow from the second output port 30 is cooled before contacting the liquid at the bottom of the cylinder through the heat exchange tube 34. This lowers the temperature of the liquid ethane or more condensable hydrocarbons, reducing their saturated vapor pressure and volatility. This makes the collected liquid state more stable, preventing the liquid from evaporating again into the gas phase and being carried by the gas flow, causing secondary pollution. At the same time, the low-temperature environment inhibits the volatilization of light components in the gas above the liquid surface, reducing the negative impact on the cleanliness of the gas flow.This innovative splitter assembly utilizes the eddy current energy separation effect to achieve dual-stream airflow output (hot and cold) from a single gas source. It simultaneously provides heating and cooling airflows without the need for external heating or cooling devices. The heated airflow enhances the gas-liquid separation process, while the cooling airflow stabilizes the liquid phase after separation, achieving cascaded energy utilization and low-energy-consumption operation of the system. More significantly, during the transport process of the airflow split by the splitter assembly into the annular space through the first output port 28, the airflow inside the first output port 28 maintains a high-speed rotation. The centrifugal force generated by the rotating airflow drives droplets and condensable hydrocarbon components (ethane or higher) in the airflow to be thrown towards the inner wall of the first output port 28 and collide with the pipe wall to form a liquid film, thus realizing airflow transport and pre-separation. The separation process is carried out simultaneously. This design, which completes the initial gas-liquid separation within the conveying pipeline, places the separation function before the liquid enters the annular space. This reduces the droplet content in the airflow entering the annular space and alleviates the processing load on subsequent multi-stage separation components such as the baffle 38 and the baffle 42. The separated droplets flow along the pipe wall of the first output port 28 to the outlet end, where they encounter the coalescing component 35 installed between the two cylinders. This prevents the droplets from being carried back into the annular space by the airflow, achieving timely separation and discharge of the droplets. This avoids the accumulation of droplets at the outlet of the first output port 28, which would then be broken into smaller droplets by the high-speed airflow and enter the annular space, increasing the separation difficulty. This invention innovatively integrates the first output port 28 of the conveying pipeline, the separation function, and the droplets... The integrated collection and discharge system allows the first output port 28 to function not only as an airflow delivery channel but also as a cyclone pre-separator and droplet guide channel. Combined with the interception and guiding effect of the coalescing component 35, coarse separation and liquid discharge are completed before the airflow enters the main separation area, simplifying the device structure and improving separation efficiency. More importantly, it transforms heavy hydrocarbons that were originally in a solid or near-freezing point state in the BOG into a liquid state. This is mainly because liquid ethane or higher condensable hydrocarbons have better fluidity and dischargeability. Droplets can be wetted and spread on the surfaces of separation components such as the baffle plate 42 and the baffle plate 38, and then converge and flow through the liquid guide channel 48 and the liquid inlet channel, smoothly discharging from the device. Meanwhile, solid ethane or higher condensable hydrocarbons... Although hydrocarbon particles are easily settled by gravity, they tend to adhere to and accumulate on the internal surfaces of the device, such as the pipe walls, gas distribution holes 55, swirl channels 58, and baffles 42, forming a solid deposit layer that gradually blocks the airflow channels and the fine structure of the separation components. The solid particles cannot be discharged through the liquid guiding system and require shutdown for cleaning, which seriously affects the continuous operation and separation efficiency of the device. Liquid ethane or higher condensable hydrocarbons can coalesce into larger droplets under the action of swirling and collision, enhancing the gravity settling effect, while solid particles are difficult to coalesce. After being collected, liquid ethane or higher condensable hydrocarbons can be continuously discharged through the liquid outlet valve, achieving continuous separation and removal of materials, while solid matter will accumulate at the bottom of the device, affecting the airflow distribution and liquid collection.Therefore, heating the system to convert solid or near-solid ethane or higher condensable hydrocarbons into a liquid state is to achieve continuous and efficient separation and smooth discharge of ethane or higher condensable hydrocarbons, avoiding equipment failures and operational interruptions caused by solid material blockage and accumulation, and ensuring long-term stable operation of the unit.

[0032] Furthermore, a booster compressor 32 is provided on the outside of the first cylinder 27, and a heat exchange tube 34 is connected to the end of the second output port 30. The heat exchange tube 34 is sealed and passes through the interior of the first cylinder 27 and the second cylinder 36 and is coiled. The other end of the heat exchange tube 34 passes through the exterior of the two cylinders and is connected to the input end of the booster compressor 32. The output end 33 of the booster compressor 32 is connected to the input port 31 through a tee. The input port 31 is connected to the BOG (Boot Regulator) to guide the airflow into the cylinder for pretreatment. It should be noted that... The booster 32, heat exchange tube 34, and heat exchange tube assembly form a closed-loop circulation system, realizing the recovery and utilization of cooling airflow and the cascade utilization of energy. The heat exchange tube 34 connected to the end of the second output port 30 (short tube body) leads the cooling airflow generated by the split tube assembly to the first cylinder 27 and the second cylinder 36, where it is coiled. The cooling airflow absorbs the heat of liquid ethane or condensable hydrocarbons, lowering the temperature of the liquid ethane or condensable hydrocarbons to make them more stable and suppress volatilization. At the same time, the cooling airflow recovers the liquid... The heat from ethane or condensable hydrocarbons avoids energy waste. The output end 33 of the booster 32 is connected to the input port 31 via a tee. The recirculated airflow, boosted by the booster 32, mixes with the fresh feed gas from the BOG at the tee. The mixed airflow re-enters the splitter assembly from the input port 31 for a new round of hot and cold separation and gas-liquid separation. This closed-loop circulation system realizes the recovery and reuse of the cooled airflow, avoiding the direct discharge of the low-temperature airflow generated after energy separation, which would cause a loss of cooling capacity. The cooling capacity carried by the recirculated airflow participates in a new energy separation process when it re-enters the splitter assembly, reducing the system's demand for external energy. The heat exchange tube 34 recovers the heat from liquid ethane or condensable hydrocarbons while preheating the recirculated airflow, reducing the energy consumption of the booster 32. The booster 32 compensates for pressure loss without requiring significant heating of the low-temperature airflow. The mixing of the recirculated airflow with the fresh BOG regulates the temperature and pressure of the airflow entering the device, optimizes the operating conditions of the splitter assembly, and improves the efficiency of hot and cold separation and pre-separation.

[0033] The above embodiments describe 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. Modifications and variations made by those skilled in the art without departing from the spirit and scope of the invention should be within the protection scope of the appended claims.

Claims

1. A multi-stage purification, low-energy-consumption natural gas helium extraction pretreatment device, characterized in that, The pretreatment mechanism includes a second cylinder (36) and a first cylinder (27) nested together, with an annular space between the two cylinders; a diversion tube assembly is fixed on the first cylinder (27), the diversion tube assembly includes an input port (31), a first output port (28) and a second output port (30), the first output port (28) extends through the first cylinder (27) into the annular space, a spiral guide band (37) is provided on the inner wall of the first cylinder (27), and baffles (38) are spaced along the circumferential direction inside the annular space above the first output port (28); a liquid trapping tube (41) is installed at the connection of the tops of the two cylinders, and the liquid trapping tube (41) is connected to the top of the first cylinder (27).

2. The multi-stage purification, low-energy-consumption natural gas helium extraction pretreatment device according to claim 1, characterized in that, The baffle (38) is an arc-shaped plate with one end fixed to the inner or outer cylinder and the other end gradually extending radially toward the opposite cylinder. There is a radial distance between the inner and outer cylinders to form a fluid channel. The baffle (38) has a smooth arc-shaped guide surface. Both the baffle (38) and the inner wall of the first cylinder (27) in the same radial direction are equipped with baffles (42). The baffles (42) are installed at intervals along the circumferential direction and are alternately arranged on both sides of the annular space.

3. The multi-stage purification, low-energy-consumption natural gas helium extraction pretreatment device according to claim 2, characterized in that, The baffle plate (42) has a T-shaped plate structure, including a longitudinal plate (43) and a transverse plate. The two ends of the transverse plate of the baffle plate (42) extend toward the longitudinal plate (43) to form a droop (44). Multiple serrated strips (50) are fixed on the transverse plate between the droop (44) and the longitudinal plate (43). A liquid-guiding groove is formed between adjacent serrated strips (50) along the length direction of the longitudinal plate (43). Several through grooves (45) are opened on the longitudinal plate (43) along the length direction. Dog teeth (49) are fixed at the opening of the through grooves (45). The dog teeth (49) form a staggered channel on both sides of the opening of the through groove. The through grooves (45) are recessed along the length direction to form a liquid-guiding groove (48). The liquid-guiding groove (48) and the liquid-guiding groove guide the accumulated droplets to the bottom of the baffle plate (38).

4. The multi-stage purification, low-energy-consumption natural gas helium extraction pretreatment device according to claim 3, characterized in that, The bottom of the baffle (38) extends outward to form a tray (46), which is a hollow cavity structure. The bottom end of the baffle (42) extends into the cavity of the tray (46). The liquid guide groove (48) and the liquid inlet groove are connected to the cavity of the tray (46). A guide pipe (47) is provided in the cavity of the tray (46), and the other end of the guide pipe (47) extends into the internal accommodating space of the second cylinder (36). A second tray is provided at the bottom of the baffle plate (42) on the inner wall. The second tray is a hollow cavity structure. The liquid guide groove (48) and liquid inlet groove of the baffle plate (42) located on the inner wall of the first cylinder (27) are connected to the cavity of the second tray, forming a flow channel in the cylinder wall of the first cylinder (27). One end of the flow channel is connected to the cavity of the second tray, and the other end of the flow channel extends to the bottom of the first cylinder (27) and is connected to the internal accommodating space of the cylinder.

5. A multi-stage purification, low-energy-consumption natural gas helium extraction pretreatment device according to claim 4, characterized in that, The bottom end of the second cylinder (36) is provided and fixedly installed inside the bottom of the first cylinder (27). The bottom of the second cylinder (36) is provided with an opening that communicates with the accommodating space of the first cylinder (27). The bottom end of the first cylinder (27) is provided with a liquid outlet valve.

6. A multi-stage purification, low-energy-consumption natural gas helium extraction pretreatment device according to claim 1, characterized in that, The top of the second cylinder (36) and the first cylinder (27) are both conical inclined structures, and the top of each has an opening. The liquid-catching cylinder (41) is connected between the two top openings of the second cylinder (36) and the first cylinder (27). A guide ring (40) is provided on the bottom outer periphery of the liquid-catching cylinder (41), and the guide ring (40) is fixedly connected to the second cylinder (36). The liquid-catching cylinder (41) includes a third cylinder. Several guide grooves (51) are opened axially along the outer periphery of the third cylinder. Several arched grooves (52) are provided between two adjacent guide grooves (51). An air outlet (53) is opened through the third cylinder wall at the top of the arched groove (52). A serrated protrusion is provided on the arched groove (52) in front of the air outlet (53).

7. A multi-stage purification, low-energy-consumption natural gas helium extraction pretreatment device according to claim 1, characterized in that, A coalescing component (35) is provided outside the first output port (28). The coalescing component (35) is fixedly installed between the two cylinders. The coalescing component (35) is a wire mesh, a honeycomb structure or a ceramic ring.

8. A multi-stage purification, low-energy-consumption natural gas helium extraction pretreatment device according to claim 1, characterized in that, The shunt assembly also includes a sleeve (29), on which the input port (31) is provided. Protrusions (54) are fixed at both ends of the sleeve (29), and a tube body is fixedly inserted inside the protrusions (54). Both ends of the tube body extend away from the protrusions (54) to form a first output port (28) with a long tube structure and a second output port (30) with a short tube structure. A cone (56) is fixed at the end of the first output port (28), located inside the first output port (28), and the diameter of the bottom surface of the cone (56) is smaller than... The inner diameter of the first output port (28) is provided with several air distribution holes (55) on the tube between the two protrusions (54); the inner end of the second output port (30) is provided with a conical opening, the small end of the conical opening is close to the protrusion (54); a vortex cylinder (57) is fixedly sleeved inside the tube between the two protrusions (54), the vortex cylinder (57) is a cylindrical structure, and several vortex grooves (58) are arrayed on one end of the vortex cylinder (57) close to the cone (56), the outer diameter of the tube on the outer periphery of the vortex groove (58) is smaller than the outer diameter of the vortex cylinder (57).

9. A multi-stage purification, low-energy-consumption natural gas helium extraction pretreatment device according to claim 1, characterized in that, A booster compressor (32) is provided on the outside of the first cylinder (27). A heat exchange tube (34) is connected to the end of the second output port (30). The heat exchange tube (34) is sealed and passed through the inside of the first cylinder (27) and the second cylinder (36) and then coiled. The other end of the heat exchange tube (34) passes through the outside of the two cylinders and is connected to the input end of the booster compressor (32). The output end (33) of the booster compressor (32) is connected to the input port (31) through a tee.

10. A multi-stage purification, low-energy-consumption natural gas helium extraction pretreatment device according to claim 1, characterized in that, The spiral guide belt (37) is fixedly installed on the inner wall of the first cylinder (27) to guide the airflow to rotate upward along the axial direction.

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