A krypton-xenon column bottom evaporation heating device

Abstract

The utility model relates to a kind of krypton xenon tower bottom evaporation heating devices, including krypton xenon concentration tower body and the coil heat exchanger being located at the bottom of tower body, coil heat exchanger is variable-diameter-variable-pitch coil structure, along the radial direction of tower body is divided into central region and edge region, the pipe diameter and pitch of the coil of central region are less than the pipe diameter and pitch of the coil of edge region;The outside of the coil of edge region is provided with spiral guide vane, and the pitch of spiral guide vane is consistent with the pitch of corresponding area coil.

Description

Technical Field

[0001] This utility model relates to a heating and heat exchange device, specifically to a krypton-xenon tower bottom evaporation heating device. Background Technology

[0002] Krypton and xenon, as rare gases, are widely used in fields such as electronic chip manufacturing, medical imaging (e.g., xenon CT), and dark matter detection. Their purification relies on cryogenic distillation processes, and the evaporation heating device at the bottom of the krypton-xenon concentration tower is the core equipment for realizing this process. This device provides heat to the liquid oxygen / krypton-xenon mixture at the bottom of the tower through indirect heat exchange, promoting liquid evaporation and forming a gas-liquid two-phase countercurrent flow, ultimately achieving the separation of krypton and xenon from other gases. Currently, the core heat exchange component of the krypton-xenon tower bottom evaporation heating devices commonly used in industrial and scientific research fields is mostly a coil-type heat exchanger. This heat exchanger is immersed in the liquid at the bottom of the tower, and heat transfer is achieved by introducing a heating medium (such as nitrogen). It is a key structure to ensure separation efficiency and operational safety.

[0003] However, existing coil heat exchangers and bottom flow channel designs have two major technical limitations that severely restrict the heat transfer efficiency and operational safety of the equipment: Firstly, the coil structure leads to uneven heat transfer and localized inefficiency. Existing equipment typically uses coils with fixed diameters and pitches, such as φ12×1.5mm heat exchange tubes wound with a uniform pitch to form the heat exchange area. Due to significant radial differences in the flow characteristics of the liquid at the bottom of the krypton-xenon enrichment tower—the central region experiences stronger evaporation disturbances and higher flow velocities, while the peripheral region, far from the disturbance source, has relatively gentler flow—the fixed coil structure cannot adapt to this difference: in the central region, the fixed coil diameter results in insufficient heat exchange area density, failing to fully utilize the heat transfer potential brought by the high disturbances; in the peripheral region, the larger diameter and fixed pitch increase flow resistance, further reducing the actual flow velocity and leading to a significant decrease in the heat transfer coefficient, even forming "unevaporated dead zones." The long-term retention of liquid oxygen in these dead zones easily leads to the accumulation of hydrocarbons (such as methane and acetylene), which pose an explosion risk in the cryogenic liquid oxygen environment, directly threatening the safe operation of the equipment.

[0004] Secondly, there is the issue of stagnant flow zones and impurity deposition caused by the design of the flow channel at the bottom of the tower. To facilitate coil installation and maintenance, existing devices typically leave a 50-80mm gap between the coil and the inner wall of the tower bottom. This gap, being far from the main flow channel, results in extremely low flow rates for the liquid oxygen / krypton-xenon mixture, forming a stable "stagnant flow zone." Within this stagnant flow zone, liquid turnover is slow, preventing normal gas-liquid exchange and making it a primary deposition area for hydrocarbons, dust, and other impurities. These impurities, adhering to the tower wall and the outer wall of the coil, further reduce the heat transfer efficiency of the coil. Furthermore, as the deposition increases, these impurities may flow with the liquid into subsequent purification stages, affecting the purity of the krypton-xenon product. More importantly, the long-term accumulation of deposited hydrocarbons significantly increases the local safety risks at the bottom of the tower. Currently, the industry largely relies on external cryogenic adsorbers for pretreatment of the raw liquid oxygen. However, this method only reduces the impurity content in the raw material and cannot solve the stagnant flow zone deposition problem caused by the defective flow channel structure, making it difficult to fundamentally eliminate safety hazards and efficiency losses.

[0005] In summary, the limitations of existing krypton-xenon tower bottom evaporation heating devices in terms of coil structure and flow channel design result in problems such as low heat transfer efficiency, large regional differences, and high risk of impurity deposition. They cannot meet the requirements of "high efficiency, safety, and stability" for industrial-grade high-yield separation and scientific research-grade ultra-high purity purification, and there is an urgent need to optimize and improve them to address the above-mentioned structural defects. Utility Model Content

[0006] The main objective of this invention is to provide a krypton-xenon tower bottom evaporation heating device to solve the above-mentioned problems.

[0007] To achieve the above objectives, this utility model provides a krypton-xenon tower bottom evaporation heating device, including a krypton-xenon concentration tower body and a coil-type heat exchanger located at the bottom of the tower body. The coil-type heat exchanger is a variable diameter-variable pitch coil structure, divided into a central region and an edge region along the radial direction of the tower body. The diameter and pitch of the coil in the central region are smaller than those of the coil in the edge region. A spiral guide plate is provided on the outer side of the coil in the edge region, and the pitch of the spiral guide plate is consistent with the pitch of the coil in the corresponding region.

[0008] Preferably, the radial width of the spiral guide plate is adapted to the bottom radius of the tower body and covers the entire gap area between the coil and the inner wall of the tower body.

[0009] Preferably, the central and edge regions of the variable diameter-variable pitch coil are integrally formed, and the coils in the two regions are sealed and connected by a transition joint, the material of which is the same as that of the heat exchange tube.

[0010] Preferably, the upper and lower edges of the spiral guide plate are provided with rounded corners.

[0011] The beneficial effects of this utility model are as follows: 1. Highly efficient heat transfer adaptable to flow field characteristics: The system employs a variable-diameter, variable-pitch coil design with a "fine inner diameter and coarse outer diameter, dense inner diameter and sparse outer diameter" configuration. This design increases the local heat transfer area density in the central, highly turbulent region through the finer diameter and denser spacing of the coils, fully utilizing the heat transfer potential from high flow velocities. Conversely, in the gently sloping edge regions, the coarser diameter and more extensive spacing of the coils reduce flow resistance and prevent localized liquid accumulation. This synergistic effect reduces the difference in heat transfer coefficients between different regions at the bottom of the tower to less than 10%, improving overall heat transfer efficiency by 15%–20%. This also reduces the energy consumption of the heating medium (such as nitrogen), enabling low-energy operation of the unit.

[0012] 2. Eliminate heat transfer dead zones: The sparse, coarse-diameter pipe design at the edge, combined with the guiding effect of the spiral guide plate, completely solves the problem of "unevaporated dead zones" at the edge of traditional fixed-structure coils. This allows the liquid oxygen / krypton-xenon mixture to participate in effective heat exchange throughout the entire bottom region of the tower, avoiding heat waste caused by local liquid stagnation and further improving energy utilization. Attached Figure Description

[0013] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0014] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0015] Explanation of reference numerals in the attached figures 10. Edge region; 20. Central region; 30. Spiral guide vane; 40. Water inlet end; 50. Water outlet end. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Many specific details are set forth in the following description to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0017] like Figure 1As shown in the figure, this embodiment discloses a krypton-xenon tower bottom evaporation heating device, including a krypton-xenon concentration tower body and a coiled heat exchanger located at the bottom of the tower body. The coiled heat exchanger is immersed in the liquid at the bottom of the tower. The coiled heat exchanger is a variable diameter / variable pitch coil structure, divided radially into a central region 20 and an edge region 10. The coil in the central region 20 uses heat exchange tubes with a diameter of φ8×1mm, wound with a pitch of 1.5 times the tube diameter. The coil in the edge region 10 uses heat exchange tubes with a diameter of φ15×2mm, wound with a pitch of 2.5 times the tube diameter. The larger diameter end is the water inlet 40, and the smaller diameter end is the water outlet 50.

[0018] The central region 20 and the edge region 10 of the variable diameter-variable pitch coil are integrally formed, and the heat exchange tubes of the two regions are sealed and connected by a transition joint. The material of the transition joint is the same as that of the heat exchange tube.

[0019] A spiral guide plate 30 is provided on the outer side of the coil in the edge region 10. The spiral guide plate 30 is made of 06Cr19Ni10, has a thickness of 3mm, and is inclined at 5° towards the center of the tower. The gap between the spiral guide plate 30 and the inner wall of the bottom of the tower is 15mm, and the pitch of the spiral guide plate 30 is consistent with the pitch of the coil in the corresponding region. Preferably, the radial width of the spiral guide plate 30 is adapted to the radius of the bottom of the tower and covers the entire gap area between the coil and the inner wall of the tower. Both the upper and lower edges of the spiral guide plate 30 have rounded corner structures with a radius of 2-3mm.

[0020] Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

Claims

1. A krypton-xenon tower bottom evaporation heating device, comprising a krypton-xenon concentration tower body and a coil-type heat exchanger disposed at the bottom of the tower body, characterized in that, The coil heat exchanger is a variable diameter-variable pitch coil structure, which is divided into a central region and an edge region along the radial direction of the tower body. The diameter and pitch of the coil in the central region are smaller than those of the coil in the edge region. A spiral guide plate is provided on the outside of the coil in the edge region, and the pitch of the spiral guide plate is the same as that of the coil in the corresponding region.

2. The krypton-xenon tower bottom evaporation heating device according to claim 1, characterized in that, The radial width of the spiral guide plate is adapted to the bottom radius of the tower body and covers the entire gap area between the coil and the inner wall of the tower body.

3. The krypton-xenon tower bottom evaporation heating device according to claim 1, characterized in that, The central and edge regions of the variable diameter-variable pitch coil are integrally formed structures, and the coils in the two regions are sealed and connected by a transition joint. The material of the transition joint is the same as that of the heat exchange tube.

4. The krypton-xenon tower bottom evaporation heating device according to claim 1, characterized in that, The upper and lower edges of the spiral guide plate are both provided with rounded corners.

Images