Refrigeration cycle evaporator for xenon extraction in air separation plant and method of use thereof

Abstract

The application discloses a refrigeration cycle evaporator for extracting xenon in air separation equipment and a use method thereof, relates to the technical field of refrigeration evaporators, and is characterized in that a precooling cavity and a cryogenic cavity are arranged in the evaporation box, so that a medium-temperature and medium-pressure gas-liquid two-phase refrigerant is formed in the precooling section, the mixed gas is preliminarily cooled in the precooling cavity, part of the oxygen is condensed, and the xenon still moves downward in a gaseous state after precooling; at this time, part of the nitrogen and oxygen in the mixed gas will remain in a gaseous state, and gradually separates from the mixed gas and is lifted and discharged under the density difference, so that most of the light impurities are shaken off in advance, and the impurities of the mixer entering the cryogenic cavity are less. Meanwhile, after passing through the two-stage electronic throttle valve, a low-pressure and super-low-temperature gas-liquid two-phase refrigerant is formed, so that the precooled mixed gas can be greatly heat-absorbed after entering the cryogenic cavity, and under the condition that the boiling points are different, the xenon is condensed in a large amount, the oxygen is condensed in a small amount, and other impure gases are basically not condensed, so that the xenon is liquefied and extracted.

Description

Technical Field

[0001] This application relates to the field of refrigeration evaporator technology, and in particular to a refrigeration cycle evaporator for xenon extraction in an air separation unit and its usage method. Background Technology

[0002] In the xenon extraction process of air separation equipment, the evaporator is the core heat exchange equipment for realizing the removal of light components and the deep cryogenic liquefaction and enrichment of xenon. Its structural design directly determines the refrigeration efficiency, the effect of light component removal and the purity of xenon purification.

[0003] Currently, the evaporators used in the xenon extraction process in air separation typically employ a single-tube spiral arrangement with added heat dissipation fins to increase the heat exchange area. This allows the xenon-oxygen-rich mixture to travel through the gaps within the evaporator and exchange heat with it in contact. However, the existing evaporator structure still has many shortcomings in practical applications, making it difficult to meet the requirements for efficient and stable xenon extraction. In particular, a large number of light components in the mixture directly contact the evaporator along with the xenon. These useless impurities consume a significant amount of the evaporator's effective cooling capacity. Furthermore, after xenon liquefaction, these light components are mixed extensively within the liquid xenon, reducing its purity.

[0004] The existing single-pipe structure of evaporators means that the refrigerant mainly undergoes natural flow heat exchange, and the fluid flow is mostly laminar. Liquid film and stagnant cold gas layers easily form on the heat exchange wall, resulting in low heat exchange efficiency and insufficient utilization of cooling capacity. This not only affects the removal efficiency of light components such as nitrogen, but also increases the energy consumption of the refrigeration system. Furthermore, the uneven distribution of fluid velocity within the evaporator can easily lead to localized cold accumulation or heat exchange dead zones, further reducing the stability of light component removal.

[0005] In existing evaporators, heat exchange relies solely on the refrigerant's own flow within the refrigerant channel, resulting in limited heat exchange intensity. Furthermore, after prolonged operation, the heat exchange walls are prone to scaling and blockage due to impurities and liquid film adhesion, leading to a continuous decline in heat exchange efficiency. This necessitates frequent shutdowns for cleaning, affecting the continuity of xenon extraction. While some evaporators have attempted to incorporate turbulence structures, they often rely on external power, which not only increases energy consumption but also makes them unsuitable for the enclosed working conditions inside the evaporator. Summary of the Invention

[0006] This application proposes a refrigeration cycle evaporator for xenon extraction in an air separation unit and its usage method. It features a pre-cooling section to remove some light components, a deep-cooling section for heat exchange with the purified mixture, multiple fan blades inside the evaporator tube to agitate the refrigerant, fan blades combined with centrifugal balls and springs to create disordered oscillation of the evaporator tube due to variations in the refrigerant at different locations, the mixed gas impacting the impeller sleeve to rotate, and the disordered oscillation of the evaporator tube altering the flow state of the mixed gas, thus changing the impact force of the mixed gas on the impeller sleeve at different positions. This addresses the problems of low heat exchange efficiency and poor separation effect in existing air separation unit circulating evaporators.

[0007] To achieve the above objectives, this application adopts the following technical solution: a refrigeration cycle evaporator for xenon extraction in an air separation unit, comprising an evaporation chamber, wherein the evaporation chamber is provided with an exhaust chamber, a precooling chamber, a transition chamber, a cryogenic chamber and a separation chamber arranged from top to bottom; This is used to set up different heat exchange chambers and separation chambers for light components, so as to avoid unnecessary heat transfer in various places.

[0008] The evaporator is equipped with multiple sets of evaporator tubes that are close to each other. The evaporator tubes are divided into a precooling section located in the precooling chamber and a deep cooling section located in the deep cooling chamber. By setting up multiple sets of evaporator tubes, a larger space can be covered, thereby increasing the effective heat exchange area.

[0009] The evaporator tube consists of multiple bends and multiple straight tubes connecting the bends. Increase the effective coverage space of a single evaporator tube.

[0010] A flexible tube is installed on one side of the precooling section, and a primary electronic throttle valve is installed at one end of the flexible tube. A secondary electronic throttle valve is installed between the precooling section and the cryogenic section. The temperature and pressure of the refrigerant passing through the throttling valves are controlled by adjusting the variables of the primary and secondary electronic throttling valves.

[0011] A blade sleeve is provided on the outer side of the straight pipe, a transmission ring is provided at the axial center of the straight pipe, a connector is provided on the inner side wall of the transmission ring, and a rotating shaft with fan blades is provided at the center of the connector. By setting the impeller sleeve to act as heat dissipation fins, the contact area for heat exchange is increased, and the power of the mixed gas is received and converted into rotational motion. The refrigerant can impact the fan blades, driving the shaft to rotate while disturbing the refrigerant in the evaporator tube.

[0012] Preferably, a wire mesh demister I is provided on one side of the exhaust chamber, an air inlet is provided on the top of the evaporator away from the wire mesh demister I, a liquid collection pipe is provided at the bottom of the evaporator, an electrically controlled valve is provided in the liquid collection pipe, and symmetrical exhaust pipes are provided on both sides of the top of the separation chamber, with a wire mesh demister II provided in the exhaust pipe.

[0013] By setting up wire mesh demister I and wire mesh demister II, the tiny liquid phase in the gas phase is intercepted.

[0014] Preferably, the top sidewall of the precooling chamber is inclined and expands towards the wire mesh demister I.

[0015] This is used to guide the separated light components towards the wire mesh demister I.

[0016] Preferably, multiple sets of evaporator tubes are arranged vertically, and the straight and curved tubes on adjacent evaporator tubes are arranged alternately.

[0017] Used to increase the coverage area and the heat exchange contact area.

[0018] Preferably, the end of the primary electronic throttle valve away from the flexible tube is provided with an inlet pipe that penetrates one side of the top of the evaporator, one end of the cryogenic section is provided with a flexible tube, and the other end of the flexible tube is provided with an outlet pipe that penetrates one side of the bottom of the evaporator.

[0019] By installing flexible tubes, the stability of other pipes can be ensured when the evaporator tube swings.

[0020] Preferably, the secondary electronic throttle valve is located in the transition chamber.

[0021] Preferably, the impeller sleeve consists of an inner sleeve and impellers evenly distributed circumferentially on the outer side wall of the inner sleeve. The inner side wall of the inner sleeve is fitted with the outer side wall of the straight pipe, and the impellers are in the shape of straight plates in the axial direction.

[0022] This causes the mixed gas to impact the impeller laterally, driving the impeller to rotate.

[0023] Preferably, symmetrical clamps are provided on both sides of the straight pipe, and the two ends of the inner sleeve are respectively fitted together.

[0024] Preferably, a swing arm is provided on one side of the rotating shaft, and a centrifugal ball is provided at the end of the swing arm away from the rotating shaft. Multiple collars are provided on the evaporation tube, the inlet tube, and the outlet tube, and springs are provided on the collars to connect with the evaporation box.

[0025] Used to provide the power for the reciprocating oscillation of the evaporator tube.

[0026] A method of using a refrigeration cycle evaporator for xenon extraction in an air separation unit, comprising the following steps: S1. High-pressure liquid refrigerant passes through a first-stage electronic throttling valve to form a medium-pressure, medium-temperature gas-liquid two-phase refrigerant which enters the pre-cooling section. S2. The mixture enters the precooling chamber through the air inlet, comes into direct contact with the precooling section, and impacts the impeller sleeve downwards, causing the impeller sleeve to rotate. Some light components are separated from the mixture at this point. S3. The medium-temperature and medium-pressure gas-liquid two-phase refrigerant impacts the fan blades in the pre-cooling section, causing the fan blades to rotate and create turbulence, which in turn drives the centrifugal ball to rotate. S4. After absorbing heat in the precooling section, the medium-temperature and medium-pressure gas-liquid two-phase refrigerant passes through the secondary electronic throttling valve to form a low-pressure and low-temperature gas-liquid two-phase refrigerant that enters the cryogenic section. S5. The pre-cooled mixed gas passes through the transition chamber and enters the cryogenic chamber, where it directly contacts the cryogenic section for heat exchange and impacts the impeller sleeve, causing the impeller sleeve to rotate. S6. The low-pressure, low-temperature gas-liquid two-phase refrigerant impacts the fan blades in the cryogenic section, causing the fan blades to rotate and create turbulence, which in turn drives the centrifugal ball to rotate. S7. Centrifugal balls at different positions provide centrifugal forces of different directions and magnitudes to the evaporator tube. Combined with the external spring and the multi-point, multi-directional external forces applied by the mixed gas, the evaporator tube oscillates disorderly. S8. The disorderly oscillating evaporator tubes drive the impeller sleeve to disturb the gas mixture; S9. The mixture liquefies xenon and some oxygen in the cryogenic chamber, separating it from the excess light components.

[0027] This application provides a refrigeration cycle evaporator for xenon extraction in an air separation unit. By setting a pre-cooling chamber and a cryogenic chamber in the evaporator, the high-pressure liquid refrigerant entering the evaporator first passes through a first-stage electronic throttling valve, causing a sudden pressure drop and rapid expansion of the liquid. Part of the liquid flashes into gas, transforming into a medium-temperature, medium-pressure gas-liquid two-phase refrigerant located in the pre-cooling chamber. This causes the mixed gas to be initially cooled in the pre-cooling chamber, resulting in the condensation of some oxygen. Xenon, after pre-cooling, still moves downward in a gaseous state. At this time, some nitrogen and oxygen in the mixed gas will remain in a gaseous state and gradually detach from the mixed gas and rise away due to the density difference, thereby getting rid of most of the light impurities in advance, resulting in fewer impurities entering the cryogenic chamber of the mixer.

[0028] Meanwhile, the medium-temperature, medium-pressure gas-liquid two-phase refrigerant absorbs some heat in the pre-cooling chamber, and the liquid refrigerant partially absorbs heat and evaporates, causing a slight temperature rise. The overall refrigerant gradually transforms into a medium-temperature, medium-pressure superheated gas-liquid two-phase refrigerant (superheated refers to the refrigerant relative to the medium-temperature, medium-pressure gas-liquid two-phase refrigerant that has not yet absorbed heat). After passing through the two-stage electronic throttling valve, the pressure drops significantly again, and the temperature decreases further, forming a low-pressure, super-low-temperature gas-liquid two-phase refrigerant again. This allows the pre-cooled mixture to absorb a large amount of heat after entering the cryogenic chamber. Due to the different boiling points, xenon condenses in large quantities, oxygen condenses in small quantities, and other impurities do not condense significantly, thus liquefying and extracting xenon.

[0029] Meanwhile, by installing a rotating shaft with fan blades inside the straight tube of the evaporator, the medium-pressure, medium-temperature gas-liquid two-phase refrigerant in the pre-cooling section of the evaporator can drive the rotating shaft and fan blades to rotate when impacting the fan blades. During this process, the fluid will be forced to deflect, and the fan blades will break up large droplets, resulting in more uniform liquid atomization, intensifying fluid turbulence, enhancing internal heat transfer in the gas-liquid two-phase system, increasing the heat transfer coefficient of the pre-cooling section, improving the cooling capacity utilization rate of the pre-cooling section, and optimizing the removal efficiency of light components in the mixed gas. Similarly, in the cryogenic section of the evaporator, the fan blades will also forcibly disturb the airflow, destroy the laminar boundary layer of the tube wall, significantly improve the heat transfer coefficient, eliminate local heat transfer dead zones, and improve the xenon liquefaction and enrichment efficiency.

[0030] Simultaneously, the fan blades inside the straight tube rotate after being impacted, causing the rotating shaft to drive the centrifugal balls to rotate synchronously. This causes the position of the centrifugal balls to continuously change in the circumferential direction, applying a centrifugal force to the entire evaporator tube. Combined with the external spring, this causes the evaporator tube to vibrate continuously. It should be noted that due to the differences in fluid pressure, flow rate, and flow direction of the refrigerant in each straight tube, there are differences in the rotation speed of the centrifugal balls in each straight tube. This results in a disordered overall movement direction of the evaporator tube, leading to disordered spatial changes in the gaps between adjacent evaporator tubes. This allows the mixed gas passing through the gaps to have enhanced direct contact with the evaporator tubes, increasing the contact range and extending the contact time, thereby improving heat exchange efficiency. Attached Figure Description

[0031] The accompanying drawings, which form part of this specification, illustrate embodiments disclosed in this application and, together with the specification, serve to explain the principles disclosed in this application.

[0032] This disclosure will become clearer with reference to the accompanying drawings and the following detailed description, wherein: Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a schematic diagram of the internal structure of the present invention; Figure 3 This is a schematic diagram of the evaporator structure of the present invention; Figure 4 This is a schematic diagram of the internal chamber distribution of the evaporator of the present invention; Figure 5 This is a schematic diagram of the arrangement of multiple evaporation tubes according to the present invention; Figure 6 This is a schematic diagram of the three-dimensional structure of multiple evaporation tubes of the present invention; Figure 7 This is a schematic diagram of the evaporator tube structure of the present invention; Figure 8 This is a schematic diagram showing the position of the transmission ring structure of the present invention; Figure 9 This is a schematic diagram showing the structural position of the connector of the present invention; Figure 10 This is a schematic diagram showing the position of the centrifugal ball structure of the present invention.

[0033] The components are as follows: 1. Evaporator; 2. Exhaust chamber; 21. Precooling chamber; 22. Transition chamber; 23. Deep cooling chamber; 24. Separation chamber; 3. Air inlet; 31. Wire mesh demister I; 32. Liquid collection pipe; 33. Exhaust pipe; 34. Wire mesh demister II; 4. Primary electronic throttle valve; 41. Secondary electronic throttle valve; 5. Evaporator tube; 51. Bend; 52. Straight tube; 53. Inlet pipe; 54. Outlet pipe; 55. Flexible tube; 56. Impeller sleeve; 57. Clamp; 6. Transmission ring; 61. Connecting piece; 62. Rotating shaft; 63. Swing rod; 64. Centrifugal ball; 7. Collar; 71. Spring. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0035] Example 1 Please see Figures 4 to 5 A refrigeration cycle evaporator for xenon extraction in an air separation unit includes an evaporation chamber 1, which has an exhaust chamber 2, a precooling chamber 21, a transition chamber 22, a cryogenic chamber 23 and a separation chamber 24 connected from top to bottom inside the evaporation chamber 1.

[0036] The mixture enters the pre-cooling chamber 21 through the exhaust chamber 2 for pre-cooling, causing some of the light components such as nitrogen and oxygen in the mixture to separate from the mixture and rise to the exhaust chamber 2 for discharge. Then, the pre-cooled mixture passes through the transition chamber 22 and enters the cryogenic chamber 23 for xenon liquefaction. The liquefied xenon and some oxygen fall into the separation chamber 24, while the remaining light components are discharged from the top of the separation chamber 24.

[0037] See Figures 1 to 5 A wire mesh demister I31 is fixedly connected to one side of the exhaust chamber 2, so that the light components rising in the pre-cooling section can pass through the wire mesh demister I31 after reaching the exhaust chamber 2. At this time, the wire mesh demister I31 can separate the trace amounts of liquid in these gas phases to prevent the xenon components from being entrained and lost in large quantities.

[0038] An air inlet 3 is fixedly connected to the top of the evaporator 1 on the side away from the wire mesh demister I 31, so that the mixed gas can enter the top of the evaporator 1 through the air inlet 3 and then push the mixed gas downward, while avoiding a large amount of mixed gas directly approaching the wire mesh demister I 31. A liquid collection pipe 32 is fixedly connected to the bottom of the evaporator 1, and an electric control valve is fixedly sleeved inside the liquid collection pipe 32, so that the liquefied xenon and oxygen can fall into the liquid collection pipe 32. After accumulating to a set amount, the electric control valve can be opened to draw away the liquid for the next step of separation.

[0039] Symmetrical exhaust pipes 33 are fixedly connected to both sides of the top of the separation chamber 24. A wire mesh demister II 34 is fixedly sleeved inside the exhaust pipe 33, so that the light components after passing through the cryogenic section can pass through the wire mesh demister II 34 after entering the separation chamber 24. At this time, the wire mesh demister II 34 can separate the trace amounts of liquid in these gas phases to prevent the xenon components from being entrained and lost in large quantities.

[0040] See Figure 2 , Figures 5 to 7 The evaporator 1 is equipped with multiple sets of evaporator tubes 5 that are close to each other. The evaporator tubes 5 are divided into a pre-cooling section and a deep cooling section. The evaporator tubes are composed of multiple bends 51 and multiple straight tubes 52 that connect two opposite bends 51, so that the multiple sets of evaporator tubes 5 can cover a larger area and increase the heat exchange contact area between the mixed gas and the multiple sets of evaporator tubes 5 during the flow process.

[0041] The precooling section is located in the precooling cavity 21, and the cryogenic section is located in the cryogenic cavity 23.

[0042] A flexible metal tube 55 is fixedly connected to the top opening of the precooling section. A first-stage electronic throttle valve 4 is fixedly connected to the end of the flexible tube 55 away from the evaporator tube 5. An inlet pipe 53 is fixedly connected to the end of the first-stage electronic throttle valve 4 away from the flexible tube 55. The inlet pipe 53 is fixedly connected to one side of the top of the evaporator 1.

[0043] This causes the high-pressure liquid refrigerant entering the evaporator to first pass through the first-stage electronic throttle valve 4, resulting in a sudden drop in pressure, rapid expansion of the liquid, and partial flashing of the liquid into gas. This transforms the liquid into a medium-temperature, medium-pressure gas-liquid two-phase refrigerant that enters the pre-cooling section. As a result, the mixed gas in the pre-cooling chamber 21 is initially cooled by contact with the pre-cooling section, causing some oxygen to condense. Xenon, after pre-cooling, still moves downward in a gaseous state. At this time, some nitrogen and oxygen in the mixed gas will remain in a gaseous state and gradually separate from the mixed gas and rise away due to the density difference, thereby getting rid of most of the light impurities in advance, resulting in fewer impurities entering the deep-cooling chamber 23.

[0044] During the above stage, the temperature of the precooling section can be controlled between -60°C and -80°C by adjusting variables such as the opening of the first-stage electronic throttle valve 4. The specific temperature can be adjusted according to actual needs; this is just an example.

[0045] In other words, most of the nitrogen and a small amount of oxygen here have lower boiling points and are difficult to condense in the precooling section, remaining in a gaseous state with a lower density. At this point, the upward force of this gas is greater than the downward drag force of the mainstream gas. Furthermore, in the precooling section, some oxygen and trace amounts of heavy components continuously condense and liquefy, dripping downwards. In the local gas phase space, the heavy gases continuously decrease, the light nitrogen is continuously concentrated, and the nitrogen partial pressure increases. Simply put, the heavy gases continuously "run down and become liquids," while the light gases remain in the gas phase and can only accumulate upwards. Moreover, a weak upward circulation naturally forms near the sidewall of the precooling chamber, in the heat exchange blind zone, and in the low-speed zone. Nitrogen is just enriched in these low-speed reflux zones. The downward drag force of the mainstream is weak, and buoyancy easily dominates, causing it to rise and be discharged.

[0046] After this part of the gas is removed, the temperature of the mixture decreases, some oxygen condenses and carries some gas downwards, while the density of xenon continues to increase after cooling, and it remains in a gaseous state, causing the overall density of the mixture to increase and continue to sink.

[0047] A flexible metal tube 55 is fixedly connected to the bottom opening of the cryogenic section, and a discharge pipe 54 is fixedly connected to the other end of the flexible tube 55. The discharge pipe 54 is fixedly connected through one side of the bottom of the evaporator 1.

[0048] A two-stage electronic throttle valve 41 is fixedly connected to the bottom opening of the precooling section, and the other end of the two-stage electronic throttle valve 41 is fixedly connected to the top opening of the cryogenic section.

[0049] The medium-temperature, medium-pressure gas-liquid two-phase refrigerant absorbs some heat in the pre-cooling chamber 21, and the liquid refrigerant partially absorbs heat and evaporates, causing a slight temperature rise. The overall refrigerant gradually transforms into a medium-temperature, medium-pressure superheated gas-liquid two-phase refrigerant (superheated refers to the medium-temperature, medium-pressure gas-liquid two-phase refrigerant that has not yet absorbed heat). After passing through the secondary electronic throttling valve 41, the pressure drops significantly again, and the temperature decreases further, forming a low-pressure, super-low-temperature gas-liquid two-phase refrigerant again. This allows the pre-cooled mixture to absorb a large amount of heat after entering the cryogenic chamber 23. Under the condition of different boiling points, xenon condenses in large quantities, oxygen condenses in small quantities, and other impurities do not condense at all, thus liquefying and extracting xenon.

[0050] During the above stage, by controlling variables such as the opening degree of the secondary electronic throttle valve 41, the temperature can be controlled between -110 and -125 degrees Celsius. The specific temperature can be adjusted according to actual needs; this is just an example.

[0051] The secondary electronic throttle valve 41 is located in the transition chamber 22, which allows the precooling section and the cryogenic section to be separated by a certain distance through the transition chamber 22, reducing unnecessary heat exchange between the precooling section and the cryogenic section and forming a gradient cooling.

[0052] See Figures 1 to 5The top sidewall of the precooling chamber 21 is inclined and expands towards the wire mesh demister I 31. The inclined design increases the range of the precooling chamber near the sidewall, the heat exchange blind zone, and the low-speed zone, increases the degree of upward circulation, and guides the light components to flow to this side.

[0053] See Figure 2 , Figures 5 to 8 A blade sleeve 56 is movably sleeved on the outside of the straight pipe 52. The blade sleeve 56 is composed of an inner sleeve and blades evenly distributed circumferentially on the outer wall of the inner sleeve.

[0054] The inner wall of the inner sleeve is in contact with the outer wall of the straight pipe 52. The impeller is axially straight and faces the air inlet 3. This allows the straight pipe 52 to exchange heat with the impeller by contacting the inner sleeve, causing the impeller to form heat dissipation fins, increasing the heat dissipation area. The mixed gas flowing from top to bottom impacts the impeller, causing it to rotate slowly and continuously. This changes the flow direction of the mixed gas between adjacent evaporator pipes 5 and increases the turbulence, further improving the heat exchange efficiency.

[0055] It should be noted that when the inner sleeve rotates, frictional heat will be generated between it and the straight pipe 52. This heat is negligible and far less than the cooling capacity of the refrigerant, so it will not affect the overall heat exchange.

[0056] Symmetrical clamps 57 are fixedly sleeved on both sides of the straight pipe 52. The two ends of the inner sleeve are respectively fitted with the opposite ends of the clamps 57 on both sides, so that the clamps 57 can restrict the displacement of the blade sleeve 56 in the axial direction.

[0057] Multiple sets of evaporator tubes 5 are arranged vertically, and the straight tubes 52 and bent tubes 51 on adjacent evaporator tubes 5 are arranged alternately, which increases the coverage area of ​​multiple sets of evaporator tubes 5, improves the heat exchange efficiency, and avoids interference between the impeller sleeves 56 on adjacent evaporator tubes 5.

[0058] Example 2 Please see Figure 8 Based on Embodiment 1, the straight pipe 52 consists of two axially symmetrical half-pipes and a transmission ring 6 fixedly connected between the opposite ends of the two half-pipes, which facilitates disassembly and installation.

[0059] See Figures 9 to 10 A connector 61 is fixedly connected to the inner wall of the transmission ring 6. A rotating shaft 62 is movably sleeved at the center of the connector 61. Circumferentially distributed fan blades are fixedly connected to the side wall of the rotating shaft 62.

[0060] In the precooling section of evaporator tube 5, the medium-pressure, medium-temperature gas-liquid two-phase refrigerant, upon impacting the fan blades, drives the fan blades and shaft 62 to rotate. During this process, the fluid is forced to deflect, and the fan blades break up large droplets, resulting in more uniform liquid atomization, increased fluid turbulence, enhanced internal heat transfer of the gas-liquid two-phase system, improved heat transfer coefficient of the precooling section, increased cooling capacity utilization of the precooling section, and optimized removal efficiency of light components in the mixed gas. Similarly, in the cryogenic section of evaporator tube 5, the fan blades also forcibly disturb the airflow, disrupt the laminar boundary layer of the tube wall, significantly improve the heat transfer coefficient, eliminate local heat transfer dead zones, and improve xenon liquefaction and enrichment efficiency.

[0061] The fan blades are preferably made of five blades to avoid insufficient force on a single blade or mutual interference between multiple blades. At the same time, it ensures sufficient force-bearing area so that the fan blades can stably receive the driving force of the airflow. It will not cause insufficient driving force due to too few blades, nor will it cause flow channel congestion and increase operating resistance due to too many blades. It is suitable for the mainstream operating condition of "overall downward flow" and ensures that the fan blades rotate smoothly without affecting the core heat exchange process.

[0062] The axial tilt angle of the fan blades is preferably 22 degrees. This angle can effectively withstand the impact of the airflow, while avoiding excessive local pressure drop and turbulence-induced overheating caused by an excessively large angle. At the same time, it balances "turbulence-enhanced heat transfer" and "unobstructed flow path", ensuring that the operating load will not increase due to an excessively large tilt angle.

[0063] The diameter of the fan blade is 0.8 times the inner diameter of the transmission ring 6. This ensures that the fan blade has a sufficient force-bearing area to fully receive the airflow driving force, while preventing the flow channel from being blocked due to excessively wide fan blades. It balances "turbulence-enhanced heat transfer" and "unobstructed flow channel", avoiding the impact on airflow due to excessive space occupied by the fan blades.

[0064] The thickness of the fan blades is no more than 1.2 millimeters, which reduces the weight of the fan blades themselves, reduces resistance during startup, reduces airflow resistance, and also reduces frictional heat generation, thus avoiding affecting the low-temperature environment of the cryogenic section.

[0065] The number and structure of the fan blades are set according to the actual situation, and this application only lists one such setting here.

[0066] Example 3 Please see Figure 10 Based on Embodiment 2, a rocker arm 63 is fixedly connected to one side of the rotating shaft 62 by bolts, and a centrifugal ball 64 is fixedly connected to the end of the rocker arm 63 away from the rotating shaft 62. The centrifugal ball 64 is close to the inner wall of the transmission ring 6.

[0067] See Figure 2 , Figures 5 to 7 Multiple collars 7 are fixedly sleeved on the inlet pipe 53, and springs 71 are fixedly connected to the collars 7. The other end of the springs 71 is fixedly connected to the top of the exhaust chamber 2.

[0068] A collar 7 is fixedly sleeved on the bottom tube of the precooling section, and a spring 71 is fixedly connected to the collar 7. The other end of the spring 71 is fixedly connected to one side of the transition cavity 22.

[0069] A collar 7 is fixedly sleeved on the top tube of the cryogenic section, and a spring 71 is fixedly connected to the collar 7. The other end of the spring 71 is fixedly connected to one side of the transition cavity 22.

[0070] Multiple collars 7 are fixedly sleeved on the discharge pipe 54, and springs 71 are fixedly connected to the collars 7. The other end of the springs 71 is fixedly connected to the top end of the separation chamber 24.

[0071] When the rotating shaft 62 inside the straight tube 52 rotates, it can drive the centrifugal ball 64 to rotate synchronously through the swing rod 63, so that the position of the centrifugal ball 64 changes continuously in the circumferential direction, and applies a centrifugal force of the centrifugal ball 64 to the whole evaporator tube 5. In conjunction with the external spring 71, the evaporator tube 5 vibrates continuously.

[0072] It should be noted that, due to the different fluid pressures, flow rates, liquid phase contents, and flow directions of the refrigerant in each straight pipe 52 under the influence of different areas, the rotation speed of the fan blades in each straight pipe 52 is different, and the rotation speed of the centrifugal ball 64 will also vary. This results in the overall movement direction of the evaporator tube 5 being disordered, which in turn causes disordered spatial changes in the gaps between adjacent evaporator tubes 5. As a result, the mixed gas passing through the gaps will further change its flow direction after passing through the disordered space, enhancing the direct contact with the evaporator tube 5 and the impeller sleeve 56, increasing the contact range, extending the contact time, and thus improving the heat exchange efficiency.

[0073] During this process, the downward thrust of the mixed gas is transmitted to the evaporator tube 5 through the impeller sleeve 56, resulting in the evaporator tube 5 having additional downward force as a whole, with a higher oscillation frequency. The shaking will further break the static liquid film and low-temperature boundary layer on the outer wall of the evaporator tube 5 and the impeller sleeve 56, causing the liquid film to fall off, accelerating collection, and avoiding the liquid film from hindering heat exchange.

[0074] During this process, the refrigerant inside the evaporator tube will also be affected, and the flow of the internal refrigerant will become more disordered.

[0075] Because of the irregular vibration, the lateral airflow field becomes turbulent and is no longer a stable laminar flow state. Small eddies and backflows will be generated locally, and the airflow velocity and pressure will fluctuate slightly. The airflow will no longer uniformly and straightly wash over each blade. The impact force and impact angle of the airflow on the blade sleeve 56 at different positions will change at any time.

[0076] The airflow distribution between the multi-layered staggered evaporator tubes will also change accordingly. The instantaneous airflow velocity will increase in some areas and decrease in some areas, but the overall airflow will remain unchanged. There will be no problem of airflow blockage or interruption, and it can still continuously provide rotational power for the sleeve.

[0077] The overall rotation direction will not reverse. Most of the impeller sleeves 56 will still follow the lateral airflow thrust and maintain their original direction. Only when strong backflow or vortex is generated locally will the impeller sleeves 56 at the center of the vortex experience a brief pause, deceleration, or even instantaneous reversal. After the vortex disappears, they will immediately return to their original direction and will not experience a long-term reversal.

[0078] The rotational speed of the impeller sleeve 56 will become uneven and irregular, no longer maintaining a constant speed. The speed difference of the impeller sleeve 56 in different positions will become larger. The impeller sleeve 56 located in the mainstream airflow area with small vibration amplitude has a relatively stable speed, while the impeller sleeve 56 located in the vortex area with large vibration amplitude will have fluctuating speed, or even pause briefly.

[0079] During the shaking process, the blade sleeve 56 will rotate at any time because the angle and force of the airflow impact on the blade will change constantly, and it will be unable to maintain a uniform rotation speed.

[0080] The above process can further enhance the turbulence of the mixed gas and improve the heat exchange efficiency.

Claims

1. A refrigeration cycle evaporator for xenon extraction in an air separation unit, comprising an evaporation chamber (1), characterized in that, The evaporator (1) has a connected exhaust chamber (2), a precooling chamber (21), a transition chamber (22), a cryogenic chamber (23), and a separation chamber (24) from top to bottom. The evaporator (1) is equipped with multiple sets of evaporator tubes (5) that are close to each other. The evaporator tubes (5) are divided into a precooling section located in the precooling chamber (21) and a deep cooling section located in the deep cooling chamber (23). The evaporator tube (5) consists of multiple bends (51) and multiple straight tubes (52) connecting the opposite bends (51); A flexible tube (55) is provided on one side of the precooling section, and a first-stage electronic throttle valve (4) is provided at one end of the flexible tube (55). A second-stage electronic throttle valve (41) is provided between the precooling section and the cryogenic section. A blade sleeve (56) is provided on the outer side of the straight pipe (52), a transmission ring (6) is provided at the axial center of the straight pipe (52), a connector (61) is provided on the inner side wall of the transmission ring (6), and a rotating shaft (62) with fan blades is provided at the center of the connector (61).

2. The refrigeration cycle evaporator for xenon extraction in an air separation unit according to claim 1, characterized in that, A wire mesh demister I (31) is provided on one side of the exhaust chamber (2), an air inlet (3) is provided on the top of the evaporator (1) away from the wire mesh demister I (31), a liquid collection pipe (32) is provided at the bottom of the evaporator (1), an electric control valve is provided in the liquid collection pipe (32), and symmetrical exhaust pipes (33) are provided on both sides of the top of the separation chamber (24), and a wire mesh demister II (34) is provided in the exhaust pipe (33).

3. A refrigeration cycle evaporator for xenon extraction in an air separation unit according to claim 2, characterized in that, The top sidewall of the precooling chamber (21) is inclined and expands towards the wire mesh demister I (31).

4. A refrigeration cycle evaporator for xenon extraction in an air separation unit according to claim 1, characterized in that, Multiple sets of evaporation tubes (5) are arranged vertically, and the straight tubes (52) and bent tubes (51) on adjacent evaporation tubes (5) are arranged alternately.

5. A refrigeration cycle evaporator for xenon extraction in an air separation unit according to claim 1, characterized in that, The first-stage electronic throttle valve (4) is provided with an inlet pipe (53) that runs through the top side of the evaporator (1) at one end away from the flexible tube (55), and a flexible tube (55) is provided at one end of the deep cooling section. The other end of the flexible tube (55) is provided with an outlet pipe (54) that runs through the bottom side of the evaporator (1).

6. A refrigeration cycle evaporator for xenon extraction in an air separation unit according to claim 1, characterized in that, The secondary electronic throttle valve (41) is located in the transition chamber (22).

7. A refrigeration cycle evaporator for xenon extraction in an air separation unit according to claim 3, characterized in that, The impeller sleeve (56) consists of an inner sleeve and impellers evenly distributed around the outer wall of the inner sleeve. The inner wall of the inner sleeve is in contact with the outer wall of the straight pipe (52), and the impellers are in the shape of straight plates in the axial direction.

8. A refrigeration cycle evaporator for xenon extraction in an air separation unit according to claim 7, characterized in that, Symmetrical clamps (57) are provided on both sides of the straight pipe (52) and are respectively attached to the two ends of the inner sleeve.

9. A refrigeration cycle evaporator for xenon extraction in an air separation unit according to claim 5, characterized in that, A swing arm (63) is provided on one side of the rotating shaft (62). A centrifugal ball (64) is provided at the end of the swing arm (63) away from the rotating shaft (62). Multiple collars (7) are provided on the evaporation tube (5), the inlet tube (53) and the outlet tube (54). A spring (71) is provided on the collar (7) and connected to the evaporation box (1).

10. A method of using a refrigeration cycle evaporator for xenon extraction in an air separation unit, applied to the refrigeration cycle evaporator as described in claim 9, characterized in that... Including the following usage methods: S1. High-pressure liquid refrigerant passes through the first-stage electronic throttle valve (4) to form a medium-pressure, medium-temperature gas-liquid two-phase refrigerant that enters the pre-cooling section. S2. The mixture enters the precooling chamber (21) through the air inlet (3), comes into direct contact with the precooling section, and impacts the impeller sleeve (56) downwards, causing the impeller sleeve (56) to rotate, and some light components are separated from the mixture here; S3, the medium-temperature and medium-pressure gas-liquid two-phase refrigerant impacts the fan blades in the precooling section, causing the fan blades to rotate and create turbulence, and driving the centrifugal ball (64) to rotate; S4. After absorbing heat in the precooling section, the medium-temperature and medium-pressure gas-liquid two-phase refrigerant passes through the secondary electronic throttling valve to form a low-pressure and low-temperature gas-liquid two-phase refrigerant that enters the cryogenic section. S5. The pre-cooled mixed gas passes through the transition chamber (22) and enters the cryogenic chamber (23), where it directly contacts the cryogenic section for heat exchange and impacts the impeller sleeve (56) there, causing the impeller sleeve (56) to rotate. S6. The low-pressure, low-temperature gas-liquid two-phase refrigerant impacts the fan blades in the cryogenic section, causing the fan blades to rotate and create turbulence, and also causing the centrifugal ball (64) to rotate. S7. Centrifugal balls (64) at different positions provide centrifugal forces of different directions and magnitudes to the evaporator (5), which, together with the external spring (71) and the multi-point, multi-directional external forces applied by the mixed gas, cause the evaporator (5) to swing disorderly. S8. The disorderly oscillating evaporator tube (5) drives the impeller sleeve (56) to disturb the mixed gas; S9. The mixture liquefies xenon and some oxygen in the cryogenic chamber, separating it from the excess light components.

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