Molecular sieve apparatus in an air separation plant

Abstract

The application discloses a molecular sieve device in an air separation device and belongs to the technical field of air separation. The device comprises a spherical shell, one side of the spherical shell is connected with an air inlet pipe, a support is arranged in the spherical shell, a spherical net body is arranged at the end of the support away from the spherical shell, a molecular sieve is arranged in the wall of the spherical net body, an air outlet pipe is arranged in the center of the spherical net body, the air outlet pipe extends to the outside through the spherical net body and the spherical shell, and the mesh aperture of the spherical net body gradually increases from the side close to the air inlet pipe to the side away from the air inlet pipe. The application has the effect that the gas mixture can be uniformly dispersed from all parts of the spherical net body into the molecular sieve, the stress of the molecular sieve is balanced, the impact of sudden gas pressure change on the molecular sieve is reduced, and the phenomenon of molecular sieve rupture or performance decline is avoided.

Description

Technical Field

[0001] This application relates to the technical field of air separation, and in particular to a molecular sieve device in an air separation unit. Background Technology

[0002] Air separation equipment is a device that uses air as raw material, turns air into liquid through compression and deep freezing, and then gradually separates oxygen, nitrogen and argon and other inert gases from the liquid air through distillation.

[0003] Both PSA oxygen generators and PSA nitrogen generators rely on molecular sieves in their operation, which significantly influence the performance of an air separation unit and plays a crucial role in the air separation system. Molecular sieves are porous structures that can purify gas mixtures using pressure swing adsorption (PSA). Gas separation using molecular sieves is a physical separation method, primarily relying on the greater adsorption capacity of impurities in the gas mixture under high pressure and the smaller adsorption capacity under low pressure to separate and enrich oxygen and nitrogen from the air.

[0004] Regarding the aforementioned technologies, the gas mixture is generally introduced into the molecular sieve tank through the inlet pipe. The gas mixture may contain impurities such as moisture, oil, and particulate matter. These impurities will accumulate on the surface of the molecular sieve, forming a contamination layer. Long-term use can easily lead to the adsorption effect of the molecular sieve near the inlet pipe being lower than that of the molecular sieve far from the inlet pipe, causing the molecular sieve to become clogged. Summary of the Invention

[0005] To help solve the problem of molecular sieve clogging, this application provides a molecular sieve device for an air separation unit.

[0006] The molecular sieve device in an air separation unit provided in this application adopts the following technical solution:

[0007] A molecular sieve device in an air separation unit includes a spherical shell, an inlet pipe connected to one side of the spherical shell, a support installed inside the spherical shell, a spherical mesh installed at the end of the support away from the spherical shell, a molecular sieve installed inside the wall of the spherical mesh, and an outlet pipe disposed at the center of the spherical mesh, the outlet pipe extending to the outside through the spherical mesh and the spherical shell.

[0008] The mesh size of the spherical mesh gradually increases from the side closer to the air intake pipe to the side farther away from the air intake pipe.

[0009] By adopting the above technical solution, the spherical mesh is arranged in a spherical shape, which increases the contact area between the molecular sieve and the gas mixture, making it less likely for a contaminant layer to accumulate in a certain part of the molecular sieve. At the same time, the mesh size of the spherical mesh gradually increases from the side closer to the inlet pipe to the side farther away from the inlet pipe, so that the gas mixture can be evenly dispersed from all parts of the spherical mesh into the molecular sieve. This makes the force on the molecular sieve balanced at all points, reducing the impact of sudden gas pressure changes on the molecular sieve, which could lead to molecular sieve breakage or performance degradation. Furthermore, it makes the adsorption effect of the molecular sieve balanced at all points, effectively solving the problem of easy clogging of the molecular sieve.

[0010] Optionally, the spherical shell and the spherical mesh are arranged vertically, the air inlet pipe is connected above the spherical shell, and the air outlet pipe extends downward through the spherical mesh and the spherical shell to the outside.

[0011] By adopting the above technical solution, during the use of molecular sieves, some molecular sieves will pulverize to a certain extent. Pulverized molecular sieves tend to accumulate on the surface of intact molecular sieves, blocking the pores and thus affecting the adsorption effect. This design allows the pulverized molecular sieves to fall to the bottom of the spherical shell under the influence of gravity and airflow, reducing the accumulation of pulverized molecular sieves on the surface of intact molecular sieves. Simultaneously, the gradually increasing pore size of the spherical mesh from the side closer to the inlet pipe to the side farther away from the inlet pipe further facilitates the falling of pulverized molecular sieves to the bottom of the spherical shell, enhancing the separation effect and thus ensuring the adsorption effect.

[0012] Optionally, the spherical mesh includes a fixed mesh shell and an elastic shrinkable mesh shell. The fixed mesh shell is located inside the elastic shrinkable mesh shell. The fixed mesh shell is fixedly connected to the air outlet pipe, and the elastic shrinkable mesh shell is slidably connected to the air outlet pipe. The support is a telescopic support.

[0013] By adopting the above technical solution, some molecular sieves are pulverized and continuously worn down. The amount of molecular sieves in the spherical mesh will gradually decrease, while the elastic shrinking mesh shell can deform according to the amount of molecular sieves, making the gaps between the molecular sieves more uniform, avoiding uneven airflow, and thus minimizing insufficient adsorption.

[0014] Optionally, a collection trough is installed at the bottom of the spherical shell, the collection trough is connected to the inner cavity of the spherical shell, a recovery valve is connected to the bottom of the collection trough, a shut-off valve is installed on the air outlet pipe, and the air separation unit also includes a control module, the control module being electrically connected to the recovery valve and the shut-off valve.

[0015] By adopting the above technical solution, the pulverized molecular sieve can fall into the collection tank for temporary storage. When recycling is needed, the shut-off valve is closed and the recycling valve is opened. Under the action of airflow, the pulverized molecular sieve in the collection tank can be recycled. This solution is efficient and convenient for recycling pulverized molecular sieve, and it can also change the direction of airflow to flush the molecular sieve in the spherical mesh, which is beneficial for screening out the pulverized molecular sieve and improving the screening effect.

[0016] Optionally, a phase change material is disposed inside the sidewall of the spherical shell. The phase change material can adsorb the heat generated during the molecular sieve adsorption process and store energy. When the molecular sieve desorbs, the phase change material can release the stored energy.

[0017] By employing the above technical solution, the molecular sieve absorbs and releases heat during adsorption and desorption. In large-scale air separation units, adsorption and desorption generate significant thermal effects, leading to temperature fluctuations and increased heat load. When the molecular sieve adsorbs, it generates a large amount of heat. At this point, the phase change material undergoes a phase change at a certain temperature, absorbing heat and mitigating the thermal effect. During subsequent desorption, the energy stored in the phase change material can also be supplied to the molecular sieve for heat absorption. Therefore, by incorporating a phase change material, the thermal effects generated during molecular sieve adsorption and desorption can be alleviated, temperature fluctuations reduced, and system stability improved.

[0018] Optionally, the air separation unit further includes a thermally deformable wire and a heat-conducting pipe. One end of the thermally deformable wire is connected to the phase change material, and the other end extends to the outside of the spherical shell. The heat-conducting pipe is disposed on the outside of the spherical shell and one end is used to connect to the water cooling system. When the energy storage of the phase change material reaches a threshold, the thermally deformable wire can change its shape and contact the heat-conducting pipe.

[0019] By employing the above technical solution, when the phase change material (PCM) continues to heat up and its heat absorption cannot meet the demand, heat is transferred to the thermal deformation wire, causing it to deform and come into contact with the heat pipe. Excess heat can then be dissipated through the heat pipe, improving cooling performance. When the PCM temperature drops to a certain value, the thermal deformation wire detaches from the heat pipe, eliminating the need for further cooling and minimizing excessive energy dissipation. During molecular sieve desorption, the molecular sieve absorbs heat, and the temperature inside the spherical shell decreases. At this point, the PCM undergoes a phase change, transforming from a liquid to a solid state, releasing heat to compensate for the temperature change during desorption, reducing thermal effects and improving equipment stability.

[0020] Optionally, the inner wall of the spherical shell is configured as a heat-conducting layer, and the outer wall of the spherical shell is configured as a heat-insulating layer.

[0021] By adopting the above technical solution, the heat-conducting layer enables heat to be transferred between the phase change material and the inner cavity of the spherical shell, improving the controllability of the phase change material over the air temperature inside the spherical shell. The heat insulation layer can reduce energy loss and prevent the working environment from deteriorating.

[0022] Optionally, the spherical shell is composed of two hemispherical shells that are detachably connected.

[0023] By adopting the above technical solution, when it is necessary to replace the molecular sieve in the future, the molecular sieve can be replaced by disassembling the spherical shell.

[0024] Optionally, a vibration device is installed on the outside of the spherical shell, and the output end of the vibration device is connected to the bracket.

[0025] By adopting the above technical solution, the vibration device can shake the pulverized molecular sieve inside the spherical mesh to the bottom of the spherical shell, where it can be recycled by the collection tank, reducing the impact of the pulverized molecular sieve on the intact molecular sieve; and the vibration can make the gaps between the molecular sieves more uniform, make the airflow distribution more uniform, reduce the local overload phenomenon of the molecular sieve, and improve the utilization rate of the molecular sieve.

[0026] Optionally, the side of the spherical housing near the air intake pipe is configured as a flared opening.

[0027] By adopting the above technical solution, the impact of airflow entering the spherical shell on the local molecular sieve can be reduced, making it easier for the airflow to be evenly distributed throughout the inner cavity of the spherical shell, thus extending the service life of the molecular sieve.

[0028] In summary, this application includes at least one of the following beneficial technical effects:

[0029] 1. The gas mixture of this application can be uniformly dispersed from all parts of the spherical mesh into the molecular sieve, so that the molecular sieve is subjected to balanced forces at all points, reducing the impact of sudden gas pressure changes on the molecular sieve, which could lead to molecular sieve breakage or performance degradation. Furthermore, it can make the adsorption effect of the molecular sieve uniform at all points, effectively solving the problem of easy clogging of molecular sieves.

[0030] 2. Some molecular sieves are pulverized and continuously worn down. The amount of molecular sieves in the spherical mesh will gradually decrease. The elastic shrinking mesh shell can deform according to the amount of molecular sieves, making the gaps between the molecular sieves more uniform, avoiding uneven airflow, enhancing the adsorption effect of the molecular sieves and extending their service life.

[0031] 3. By incorporating phase change materials, the large thermal effects generated during the adsorption and desorption processes of molecular sieves can be mitigated, temperature fluctuations can be reduced, and system stability can be improved. Attached Figure Description

[0032] Figure 1 This is a cross-sectional view of the overall structure of an embodiment of this application.

[0033] Explanation of reference numerals in the attached figures:

[0034] 100. Mounting sleeve; 200. Spherical shell; 201. Heat-conducting layer; 202. Heat insulation layer; 210. Bracket; 211. Fixed mounting sleeve; 212. Telescopic rod; 220. Trumpet mouth; 230. Vibration device; 231. Vibration motor; 232. Vibration rod; 300. Air inlet pipe; 400. Spherical mesh; 401. Fixed mesh shell; 402. Elastic shrinkable mesh shell; 500. Air outlet pipe; 501. Spherical mesh cover; 502. Shut-off valve; 600. Collection tank; 601. Recovery valve; 700. Phase change material; 710. Thermal deformation wire; 720. Heat-conducting pipe. Detailed Implementation

[0035] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

[0036] This application discloses a molecular sieve device in an air separation unit. (Refer to...) Figure 1 The air separation unit includes an installation sleeve 100, a spherical shell 200 installed inside the installation sleeve 100, and an air inlet pipe 300 connected to the top of the spherical shell 200. The gas mixture enters the spherical shell 200 from top to bottom through the air inlet pipe 300.

[0037] Reference Figure 1 A support 210 is installed on the inner wall of the spherical shell 200. A spherical mesh 400 is installed at the end of the support 210 away from the spherical shell 200. A molecular sieve is installed inside the wall of the spherical mesh 400. An outlet pipe 500 is provided at the center of the spherical mesh 400. The outlet pipe 500 extends from top to bottom through the spherical mesh 400 and the spherical shell 200 to the outside. A spherical mesh cover 501 is provided at the inlet end of the outlet pipe 500. The gas mixture enters the inner cavity of the spherical shell 200 through the inlet pipe 300, then flows through the spherical mesh 400 into the inner cavity of the spherical shell 200, and is then transported to the outlet pipe 500, from where it flows out.

[0038] The spherical shell 200 has a flared opening 220 on the side near the inlet pipe 300, which expands the airflow range. The mesh size of the spherical mesh 400 gradually increases from the side near the inlet pipe 300 to the side away from the inlet pipe 300; that is, the mesh size is smaller at the top and larger at the bottom. Through this combination, the gas mixture can be evenly dispersed from all parts of the spherical mesh 400 into the molecular sieve, ensuring balanced stress on the molecular sieve and reducing the impact of sudden gas pressure changes on the molecular sieve, which could lead to sieve breakage or performance degradation.

[0039] Reference Figure 1 The spherical mesh 400 includes a fixed mesh housing 401 and an elastic shrinkable mesh housing 402. The fixed mesh housing 401 is located inside the elastic shrinkable mesh housing 402. The fixed mesh housing 401 is fixedly connected to the air outlet pipe 500. The elastic shrinkable mesh housing 402 is fixedly connected to the bracket 210 and slidably connected to the air outlet pipe 500.

[0040] The bracket 210 is a telescopic bracket, and a vibration device 230 is installed on the outer side of the spherical shell 200. In this embodiment, the bracket 210 consists of a fixed mounting sleeve 211 and a telescopic rod 212 slidably connected within the fixed mounting sleeve 211. The telescopic rod 212 is connected to the elastic shrinkable net shell 402, and a telescopic spring connects the telescopic rod 212 to the spherical shell 200. Multiple telescopic brackets 210 can be arranged along the circumference of the spherical shell 200 to fix the spherical net 400.

[0041] Meanwhile, the vibration device 230 consists of a vibration motor 231 and a vibration rod 232. The vibration motor 231 is installed on the outside of the spherical shell 200, and the vibration rod 232 is connected to the output end of the vibration motor 231, with one end extending to connect with the telescopic rod 212. The vibration rod 232 can also be configured as a telescopic rod. Multiple vibration devices 230 can be configured to connect with the telescopic rod 212 as needed to improve vibration uniformity.

[0042] During the use of molecular sieves, some molecular sieves may become pulverized to a certain extent. Pulverized molecular sieves tend to accumulate on the surface of intact molecular sieves, blocking the pores and thus affecting the adsorption effect. At this time, the vibration device 230 can shake the pulverized molecular sieves in the spherical mesh 400 to the bottom of the spherical shell 200. The amount of molecular sieves in the spherical mesh 400 will gradually decrease, and the elastic shrinking mesh shell 402 can deform according to the amount of molecular sieves, making the gaps between the molecular sieves more uniform and avoiding uneven airflow, thereby minimizing insufficient adsorption.

[0043] To recover the powdered molecular sieve at the bottom of the spherical shell 200, a collection tank 600 is installed on the outer bottom of the spherical shell 200. A through hole is provided on the side wall of the spherical shell 200 to connect the collection tank 600 with the inner cavity of the spherical shell 200, allowing the powdered molecular sieve to enter the collection tank 600. In this embodiment, the exhaust pipe 500 extends through the collection tank 600 to the outside. In other embodiments, the exhaust pipe 500 and the collection tank 600 can be installed separately.

[0044] Meanwhile, a recovery valve 601 is connected to the bottom of the collection tank 600, and a shut-off valve 502 is installed on the outlet pipe 500. Both the recovery valve 601 and the shut-off valve 502 can be electrically controlled. The air separation unit also includes a control module, which is electrically connected to the recovery valve 601 and the shut-off valve 502. When the pulverized molecular sieve in the collection tank 600 accumulates to a certain extent, the shut-off valve 502 is closed and the recovery valve 601 is opened through the control module. The inlet pipe 300 continues to circulate air. Under the action of air pressure, the pulverized molecular sieve can be blown out of the collection tank 600, thereby realizing the recovery of the pulverized molecular sieve.

[0045] During adsorption and desorption, molecular sieves absorb and release heat, resulting in significant thermal effects that cause temperature fluctuations and increased heat load. To mitigate this issue, a phase change material 700 is disposed within the sidewall of the spherical shell 200 of this application. The heat generated during molecular sieve adsorption typically ranges from room temperature to several hundred degrees Celsius, with the specific temperature depending on factors such as the thermodynamic characteristics of the adsorption reaction, the concentrations of the adsorbate and adsorbent, and the feed temperature. Therefore, when selecting the phase change material 700, it can be chosen based on specific circumstances, such as lithium bromide, which undergoes an endothermic adsorption phase change within the 100-200 degree Celsius range.

[0046] The inner wall of the spherical shell 200 is configured as a heat-conducting layer 201, and the outer wall is configured as a heat-insulating layer 202. The phase change material 700 is located between the heat-conducting layer 201 and the heat-insulating layer 202. Both the heat-conducting layer 201 and the heat-insulating layer 202 can be selected according to the actual temperature conditions. The heat-conducting layer 201 allows heat within the spherical shell 200 to be rapidly transferred to the phase change material 700. When the temperature reaches a certain value, the phase change material 700 undergoes a phase change, transforming from a solid to a liquid state, absorbing heat, thereby mitigating the phenomenon of sudden and large temperature changes during the molecular sieve adsorption process.

[0047] Reference Figure 1The spherical shell 200 also has a heat-deformation wire 710 on its sidewall. One end of the heat-deformation wire 710 extends to contact the phase change material 700, and the other end extends to the outside of the spherical shell 200. The heat-deformation wire 710 extending to the outside of the spherical shell 200 is in the form of a spring. A heat-conducting pipe 720 is installed inside the mounting sleeve 100. Under normal conditions, one end of the heat-conducting pipe 720 is positioned close to the heat-deformation wire 710, and the other end is connected to the water cooling system. Multiple heat-deformation wires 710 and heat-conducting pipes 720 can be arranged along the circumference of the spherical shell 200 to improve the cooling performance of the spherical shell 200.

[0048] When the molecular sieve continues to release heat, exceeding the heat absorption capacity of the phase change material 700, the heat is transferred to the thermoforming wire 710, causing it to deform and elongate. The thermoforming wire 710 then wraps around the outer periphery of the heat-conducting pipe 720, contacting it. Excess heat can then be dissipated through the heat-conducting pipe 720, improving cooling performance. When the temperature of the phase change material 700 drops to a certain value, the thermoforming wire 710 detaches from the heat-conducting pipe 720, eliminating the need for further cooling of the phase change material 700 and minimizing energy loss.

[0049] The phase change material 700 stores heat within itself. When the molecular sieve desorbs, it absorbs heat, causing the temperature inside the spherical shell 200 to drop. When the temperature drops to a certain value, the phase change material 700 undergoes a phase change, transforming from a liquid to a solid state and releasing heat. This heat is then transferred to the interior of the spherical shell 200, reducing the rate of temperature drop within the shell 200. Therefore, the use of the phase change material 700 effectively mitigates the thermal effects caused by molecular sieve adsorption and desorption, improving system stability.

[0050] Furthermore, in this embodiment, the spherical shell 200 is composed of two hemispherical shells that are detachably connected. The two hemispherical shells can be connected via flanges or other methods. When the molecular sieve needs to be replaced later, the two hemispherical shells 200 can be disassembled to replace the molecular sieve.

[0051] The implementation principle of the molecular sieve device in an air separation unit according to an embodiment of this application is as follows: This molecular sieve device enables the gas mixture to be uniformly dispersed and enter the molecular sieve from all points of the spherical mesh 400, ensuring balanced force on the molecular sieve at all points. This reduces the impact of sudden gas pressure changes on the molecular sieve, preventing breakage or performance degradation. Simultaneously, the pulverized molecular sieve can fall to the bottom of the spherical shell 200 under the action of the vibration device 230 and the airflow, reducing the accumulation of pulverized molecular sieve on the intact molecular sieve surface, improving adsorption, and also enabling rapid recovery of the pulverized molecular sieve, reducing resource waste.

[0052] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A molecular sieve device in an air separation unit, characterized in that: The device includes a spherical shell (200), one side of which is connected to an air inlet pipe (300). A support (210) is installed inside the spherical shell (200), and a spherical mesh (400) is installed at the end of the support (210) away from the spherical shell (200). Molecular sieves are installed inside the wall of the spherical mesh (400), and an air outlet pipe (500) is provided at the center of the spherical mesh (400). The air outlet pipe (500) extends to the outside through the spherical mesh (400) and the spherical shell (200). The mesh aperture of the spherical mesh (400) gradually increases from the side closer to the air inlet pipe (300) to the side away from the air inlet pipe (300). The spherical shell (200) and the spherical mesh (400) are arranged vertically. The air inlet pipe (300) is connected above the spherical shell (200). The air outlet pipe (500) extends downward through the spherical mesh (400) and the spherical shell (200) to the outside. The spherical mesh (400) includes a fixed mesh shell (401) and an elastic shrinkable mesh shell (402). The fixed mesh shell (401) is located inside the elastic shrinkable mesh shell (402). The fixed mesh shell (401) is fixedly connected to the air outlet pipe (500). The elastic shrinkable mesh shell (402) is slidably connected to the air outlet pipe (500). The bracket (210) is a telescopic bracket.

2. The molecular sieve device in an air separation unit according to claim 1, characterized in that, The bottom of the spherical shell (200) is equipped with a collection trough (600), which is connected to the inner cavity of the spherical shell (200). The bottom of the collection trough (600) is connected to a recovery valve (601). A shut-off valve (502) is installed on the air outlet pipe (500). The air separation unit also includes a control module, which is electrically connected to the recovery valve (601) and the shut-off valve (502).

3. The molecular sieve device in an air separation unit according to claim 1, characterized in that: The spherical shell (200) is provided with a phase change material (700) inside its sidewall. The phase change material (700) can adsorb the heat generated during the molecular sieve adsorption process and store energy. When the molecular sieve desorbs, the phase change material (700) can release the stored energy.

4. The molecular sieve device in an air separation unit according to claim 3, characterized in that: The air separation unit also includes a thermally deformable wire (710) and a heat-conducting pipe (720). One end of the thermally deformable wire (710) is connected to the phase change material (700), and the other end extends to the outside of the spherical shell (200). The heat-conducting pipe (720) is disposed on the outside of the spherical shell (200) and one end is used to connect to the water cooling system. When the energy storage of the phase change material (700) reaches the threshold, the thermally deformable wire (710) can change its shape and contact the heat-conducting pipe (720).

5. The molecular sieve device in an air separation unit according to claim 4, characterized in that: The inner wall of the spherical shell (200) is configured as a heat-conducting layer (201), and the outer wall of the spherical shell (200) is configured as a heat-insulating layer (202).

6. The molecular sieve device in an air separation unit according to claim 1, characterized in that: The spherical shell (200) is composed of two hemispherical shells that are detachably connected.

7. The molecular sieve device in an air separation unit according to claim 1, characterized in that: A vibration device (230) is installed on the outside of the spherical shell (200), and the output end of the vibration device (230) is connected to the bracket (210).

8. The molecular sieve device in an air separation unit according to claim 1, characterized in that: The spherical shell (200) is configured with a flared opening (220) on the side near the air intake pipe (300).

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