Silicon removal system for graphite cylinder of fluidized bed

Abstract

The utility model discloses a silicon removal system for a graphite cylinder of a fluidized bed, the graphite cylinder is located in the fluidized bed, the silicon removal system comprises a SiCl4 supply device for injecting SiCl4 gas into the fluidized bed, an H2 pipeline for injecting H2 into the fluidized bed, a gas discharge pipeline and a heat exchanger group, the gas exhaust pipeline is communicated with the fluidized bed and the heat exchanger group, the heat exchanger group comprises at least two heat exchangers, and the SiCl4 supply device and the H2 pipeline are respectively communicated with the heat exchanger group for heat exchange. Compared with manual and mechanical silicon removal, the silicon removal efficiency and the production efficiency are greatly improved, the silicon removal uniformity is improved, physical damage of mechanical silicon removal to the graphite cylinder is avoided, the service life of the graphite cylinder is prolonged, waste heat generated in hydrogenation reaction can be further recycled through the heat exchanger set, and the production cost is reduced. The preheating device is used for preheating SiCl4 and H2 injected into the fluidized bed, and the energy utilization rate is increased.

Description

Technical Field

[0001] This application relates to the technical field of polysilicon preparation, and particularly to a silicon removal system for a graphite cylinder in a fluidized bed. Background Art

[0002] Polysilicon is a key raw material for the production of industrial products such as integrated circuits and photovoltaic cells. The fluidized bed is an important production equipment for polysilicon. During the production process of granular silicon, heating is carried out through the graphite cylinder in the fluidized bed. However, during this process, the generated silicon will adhere to the inner wall of the graphite cylinder. The silicon adhered to the inner wall of the graphite cylinder will cause the heat transfer effect of the graphite cylinder to become worse, increase energy consumption, and also cause uneven heating of the graphite cylinder, affecting production stability.

[0003] In order to improve the service life and use effect of the graphite cylinder, it is necessary to carry out silicon removal treatment on the inner wall of the graphite cylinder. The existing silicon removal method is to carry out manual mechanical silicon removal treatment on the inner wall of the graphite cylinder during equipment maintenance. However, the manual mechanical silicon removal method has low efficiency and is prone to cause irreversible damage to the graphite cylinder. Summary of the Invention

[0004] The purpose of this application is to provide a silicon removal system for a graphite cylinder in a fluidized bed to solve the problems of low efficiency of the existing manual mechanical silicon removal treatment method and easy irreversible damage to the graphite cylinder.

[0005] To achieve one of the above application purposes, an embodiment of this application provides a silicon removal system for a graphite cylinder in a fluidized bed. The graphite cylinder is located in the fluidized bed. The silicon removal system includes an SiCl 4 gas supply device for injecting SiCl 4 gas into the fluidized bed, an H 2 pipe for injecting H 2 into the fluidized bed, a gas discharge pipe, and a heat exchanger group. The gas discharge pipe connects the fluidized bed and the heat exchanger group. The heat exchanger group includes at least two heat exchangers. The SiCl 4 supply device and the H 2 pipe are respectively connected to the heat exchanger group and exchange heat.

[0006] As a further improvement of an embodiment of this application, the at least two heat exchangers include a first heat exchanger and a second heat exchanger. The first heat exchanger and the second heat exchanger are arranged in series. The SiCl 4 supply device is connected to the first heat exchanger, and the H 2 pipe is connected to the second heat exchanger.

[0007] As a further improvement of an embodiment of this application, the SiCl 4 supply device includes SiCl connected in sequence.4 Liquid pipeline, SiCl 4 Vaporizer and SiCl 4 Gas pipeline, and the SiCl 4 Liquid pipeline is communicated with the heat exchange inlet of the first heat exchanger, and the heat exchange outlet of the first heat exchanger is communicated with the SiCl 4 Vaporizer, and the SiCl 4 Gas pipeline is communicated with the fluidized bed.

[0008] As a further improvement of an embodiment of the present application, the second heat exchanger is located downstream of the first heat exchanger.

[0009] As a further improvement of an embodiment of the present application, the desiliconization system further includes an HCl pipeline for injecting HCl gas into the fluidized bed, and the at least two heat exchangers further include a third heat exchanger, and the HCl pipeline is communicated with the third heat exchanger.

[0010] As a further improvement of an embodiment of the present application, the first heat exchanger, the second heat exchanger and the third heat exchanger are arranged in series.

[0011] As a further improvement of an embodiment of the present application, the first heat exchanger is communicated with the gas discharge pipeline, and the second heat exchanger connects the first heat exchanger and the third heat exchanger.

[0012] As a further improvement of an embodiment of the present application, the desiliconization system further includes a gas-liquid separation device, a chlorosilane collection tank and an exhaust pipe communicated with the heat exchanger group, the gas-liquid separation device is located downstream of the heat exchanger group, and the chlorosilane collection tank and the exhaust pipe are respectively connected to the gas-liquid separation device.

[0013] As a further improvement of an embodiment of the present application, the gas-liquid separation device includes a water-cooled jacket heat exchanger and a gas-liquid separation tank, the heat exchanger group is sequentially connected to the water-cooled jacket heat exchanger and the gas-liquid separation tank, and the chlorosilane collection tank and the exhaust pipe are respectively connected to the gas-liquid separation tank.

[0014] As a further improvement of an embodiment of the present application, the heat exchanger includes a cylinder body and a heat exchange tube bundle, the cylinder body encloses a heat exchange cavity, the heat exchange tube bundle is located in the heat exchange cavity, the cylinder body is provided with a heat exchange inlet, a heat exchange outlet, an air inlet and an air outlet, the heat exchange cavity communicates the air inlet and the air outlet, and the heat exchange tube bundle communicates the heat exchange inlet and the heat exchange outlet.

[0015] Compared with the prior art, the beneficial effect of the desiliconization system for the fluidized bed graphite cylinder of the present application is that: through the SiCl 4 Supply device injects SiCl into the fluidized bed4 gas, and the H 2 pipeline injects H into the fluidized bed 2 , causing SiCl 4 , H 2 to react with the silicon attached to the inner wall of the graphite cylinder to produce chlorosilane. The reaction formula is: H 2 +SiCl 4 +Si→SiH 3 Cl. In this way, the silicon attached to the inner wall of the graphite cylinder is removed through the principle of the hydrogenation process. Not only is the silicon removal effect good, realizing automated silicon removal, but also compared with manual mechanical silicon removal, the silicon removal efficiency and production efficiency are greatly improved, the silicon removal uniformity is improved, labor is saved, physical damage to the graphite cylinder caused by mechanical silicon removal is avoided, the service life of the graphite cylinder is extended, the equipment maintenance cost is reduced, and the silicon removal operation can be carried out without disassembling the graphite cylinder, reducing the equipment downtime and improving the production continuity. Further, the waste heat generated in the hydrogenation reaction can be recovered and utilized through the heat exchanger group to preheat the SiCl 4 , H 2 injected into the fluidized bed, improving the energy utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of a silicon removal system according to an embodiment of the present application;

[0017] Figure 2 is a schematic structural diagram of a silicon removal system according to another embodiment of the present application;

[0018] Figure 3 is a schematic cross-sectional structural diagram of a heat exchanger according to an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The present application will be described in detail below with reference to the specific embodiments shown in the drawings.

[0020] In the various drawings of the present application, for the convenience of illustration, the dimensions of some structures or parts are enlarged relative to other structures or parts. Therefore, it is only used to illustrate the basic structure of the subject matter of the present application.

[0021] It should be understood that although the terms "first", "second", "third", etc. may be used herein to describe various elements, structures or parameters, the described objects should not be limited by these terms. These terms are only used to distinguish these described objects from each other.

[0022] Refer Figures 1 to 2As shown in the figure, an embodiment of the present application provides a silicon removal system 100 for a fluidized bed graphite cylinder, which is used to remove the silicon deposits adhering to the inner wall of the graphite cylinder located in the fluidized bed 200.

[0023] The silicon removal system 100 includes an SiCl 4 supply device, an H 2 pipe 11, a gas discharge pipe 2, and a heat exchanger group. The SiCl 4 supply device is used to inject SiCl 4 gas into the fluidized bed 200, and the H 2 pipe 11 is used to inject H 2 into the fluidized bed 200. The gas discharge pipe 2 communicates the fluidized bed 200 with the heat exchanger group. The heat exchanger group includes at least two heat exchangers 3. The SiCl 4 supply device and the H 2 pipe 11 are respectively connected to and exchange heat with the heat exchanger group.

[0024] By injecting SiCl 4 gas into the fluidized bed 200 through the SiCl 4 supply device, and injecting H 2 into the fluidized bed 200 through the H 2 pipe 11, the silicon attached to the inner wall of the graphite cylinder reacts with SiCl 4 and H 2 to generate chlorosilane through a hydrogenation reaction. The reaction formula is: H 2 +SiCl 4 +Si→SiH 3 Cl. In this way, the silicon deposits adhering to the inner wall of the graphite cylinder are removed through the principle of the hydrogenation process. Not only is the silicon removal effect good, realizing automatic silicon removal, but also compared with manual mechanical silicon removal, the silicon removal efficiency and production efficiency are greatly improved, the silicon removal uniformity is improved, labor is saved, physical damage to the graphite cylinder caused by mechanical silicon removal is avoided, the service life of the graphite cylinder is extended, the equipment maintenance cost is reduced, and the silicon removal operation can be carried out without disassembling the graphite cylinder, reducing the equipment downtime and improving the production continuity. Further, through the heat exchanger group, the waste heat generated in the hydrogenation reaction can be recovered and used to preheat the SiCl 4 and H 2 injected into the fluidized bed 200, improving the energy utilization rate.

[0025] Specifically, the chlorosilane generated by the hydrogenation reaction occurring in the fluidized bed 200 and the unreacted SiCl 4 and H 2After the mixed gas is discharged from the fluidized bed 200, it enters the heat exchanger group through the gas discharge pipeline 2, passes through the at least two heat exchangers 3, and heats the SiCl 4 SiCl in the supply device 4 Preheat the H 2 H in pipe 11 2 Preheating not only realizes the recovery and utilization of the waste heat from the hydrogenation reaction, saving energy, but also uses the waste heat to 4 , H 2 Preheating saves SiCl 4 , H 2 The heating time is shortened, which further improves the desiliconization efficiency.

[0026] See also Figure 1 The at least two heat exchangers 3 include a first heat exchanger 3a and a second heat exchanger 3b, wherein the first heat exchanger 3a and the second heat exchanger 3b are arranged in series, and the SiCl 4 The supply device is connected to the first heat exchanger 3a, and the H 2 The pipeline 11 is connected to the second heat exchanger 3b. The mixed gas entering the heat exchanger group enters the first heat exchanger 3a and the second heat exchanger 3b successively, which can realize multi-stage recovery and utilization of the waste heat of the hydrogenation reaction and improve the utilization efficiency of energy.

[0027] Of course, the order in which the mixed gas enters the first heat exchanger 3a and the second heat exchanger 3b is related to the upstream and downstream positions of the first heat exchanger 3a and the second heat exchanger 3b. If the first heat exchanger 3a is located upstream of the second heat exchanger 3b, the mixed gas first enters the first heat exchanger 3a and then the second heat exchanger 3b. Otherwise, the mixed gas first enters the second heat exchanger 3b and then the first heat exchanger 3a.

[0028] Wherein, the SiCl 4 The supply device includes a SiCl 4 Liquid pipeline 41, SiCl 4 Vaporizer 42 and SiCl 4 Gas pipeline 43, the SiCl 4 The liquid pipeline 41 is connected to the heat exchange inlet 311 of the first heat exchanger 3a, and the heat exchange outlet 312 of the first heat exchanger 3a is connected to the SiCl 4 The vaporizer 42 is connected to the SiCl 4 The gas pipeline 43 is connected to the fluidized bed 200. 4 SiCl introduced into the liquid pipeline 41 4The liquid first enters the first heat exchanger 3a through the heat exchange inlet 311 of the first heat exchanger 3a, and uses the heat carried by the mixed gas flowing into the first heat exchanger 3a to preheat the SiCl 4 liquid. The preheated SiCl 4 liquid flows out from the heat exchange outlet 312 of the first heat exchanger 3a, and then enters the SiCl 4 vaporizer 42 for vaporization. The vaporized SiCl 4 gas is injected into the fluidized bed 200. In this way, using the heat carried by the mixed gas in the first heat exchanger 3a to preheat the SiCl 4 liquid and then vaporize it not only saves energy and preheating time, but also ensures that the SiCl 4 entering the fluidized bed 200 finally is in a gaseous state, thereby improving the hydrogenation reaction efficiency.

[0029] Furthermore, the silicon removal system 100 further includes an H 2 heater 12. The H 2 heater 12 is arranged between the second heat exchanger 3b and the fluidized bed 200 to supplement heat the H 2 preheated by the second heat exchanger 3b so that the temperature of the H 2 reaches the required temperature.

[0030] In this embodiment, the second heat exchanger 3b is located downstream of the first heat exchanger 3a. That is, the first heat exchanger 3a is connected to the gas discharge pipe 2 and the second heat exchanger 3b. In this way, the utilization of the heat carried by the mixed gas can be reasonably distributed. First, when the heat carried by the mixed gas is relatively high, the SiCl 4 liquid is preheated to meet the relatively large preheating demand of the SiCl 4 . After one heat exchange, the heat carried by the mixed gas decreases, which can meet the relatively small preheating demand of the H 2 . In this way, the energy utilization rate can be effectively improved.

[0031] Refer to Figure 2 , further, the silicon removal system 100 further includes an HCl pipeline 5 for injecting HCl gas into the fluidized bed 200. The at least two heat exchangers 3 further include a third heat exchanger 3c. The HCl pipeline 5 is communicated with the third heat exchanger 3c.

[0032] By injecting HCl gas into the fluidized bed 200, the reaction between HCl and the silicon attached to the inner wall of the graphite cylinder can be utilized to generate chlorosilane. The reaction formula is: HCl + Si → SiH 3 Cl + H 2In this way, silicon removal can be accelerated and the efficiency of silicon removal can be improved; further, the waste heat in the mixed gas after the reaction is used by the third heat exchanger 3c to preheat the HCl gas to be injected into the fluidized bed 200, thereby improving energy utilization.

[0033] Specifically, the chlorosilane generated by the reaction in the fluidized bed 200 and the unreacted SiCl 4 , H 2 After the mixed gas of HCl is discharged from the fluidized bed 200, it enters the heat exchanger group through the gas discharge pipeline 2, and the SiCl 4 SiCl in the supply device 4 Preheating, through the second heat exchanger 3b to the H 2 H in pipe 11 2 Preheating, preheating the HCl in the HCl pipeline 5 by the third heat exchanger 3c not only realizes the recovery and utilization of the reaction waste heat, saves energy, but also utilizes the waste heat to heat SiCl 4 , H 2 , HCl preheating, saving the SiCl 4 , H 2 , and the heating time of HCl further improves the desiliconization efficiency.

[0034] Among them, the H 2 The pipeline 11 and the HCl pipeline 5 each include two sections, one of which is connected to the heat exchanger group, and the other is connected to the heat exchanger group and the fluidized bed 200, so as to facilitate connection and heat exchange with the heat exchanger 3.

[0035] In the case where the H 2 In the case of heater 12, the H 2 Another section of the pipeline 11 connects the heat exchanger group and the H 2 Heater 12.

[0036] In a preferred embodiment, the first heat exchanger 3a, the second heat exchanger 3b and the third heat exchanger 3c are arranged in series. In this way, the mixed gas entering the heat exchanger group enters the first heat exchanger 3a, the second heat exchanger 3b and the third heat exchanger 3c in sequence, thereby realizing multi-stage recovery and utilization of hydrogenation reaction waste heat and improving energy utilization efficiency.

[0037] Of course, the order in which the mixed gas enters the first heat exchanger 3a, the second heat exchanger 3b, and the third heat exchanger 3c is related to the upstream and downstream positions of the first heat exchanger 3a, the second heat exchanger 3b, and the third heat exchanger 3c, and the mixed gas enters each heat exchanger 3 in order from upstream to downstream.

[0038] In a preferred embodiment, the first heat exchanger 3a is communicated with the gas discharge pipe 2, and the second heat exchanger 3b connects the first heat exchanger 3a and the third heat exchanger 3c. That is, the gas discharge pipe 2, the first heat exchanger 3a, the second heat exchanger 3b, and the third heat exchanger 3c are connected in sequence. In this way, the heat carried by the mixed gas can be reasonably distributed, and the energy utilization rate can be effectively improved.

[0039] The desiliconization system 100 further includes a gas-liquid separation device 61, a chlorosilane collection tank 62, and an exhaust pipe 63 that are communicated with the heat exchanger group. The gas-liquid separation device 61 is located downstream of the heat exchanger group, and the chlorosilane collection tank 62 and the exhaust pipe 63 are respectively connected to the gas-liquid separation device 61. Through the gas-liquid separation device 61, SiCl 4 、H 2 、HCl and chlorosilane in the mixed gas can be separated. The chlorosilane enters the chlorosilane collection tank 62, and thus the recovery and purification of chlorosilane can be realized. SiCl 4 、H2、HCl are discharged through the exhaust pipe 63 and enter the tail gas treatment section for treatment.

[0040] Specifically, the gas-liquid separation device 61 includes a water-cooled jacket heat exchanger 3 and a gas-liquid separation tank. The heat exchanger group is connected to the water-cooled jacket heat exchanger 3 and the gas-liquid separation tank in sequence. The chlorosilane collection tank 62 and the exhaust pipe 63 are respectively connected to the gas-liquid separation tank. In this way, after the high-temperature heat carried by the mixed gas is recycled through multiple stages, the heat is greatly reduced. Then, through the water-cooled jacket heat exchanger 3, the chlorosilane can be further cooled and liquefied, and then the separation of chlorosilane can be realized through the gas-liquid separation tank, so that it can be recycled after further purification, and the separated gas can enter the tail gas treatment section for treatment.

[0041] Refer to Figure 3 , in which the heat exchanger 3 includes a cylinder body 31 and a heat exchange tube bundle 32. The cylinder body 31 encloses a heat exchange cavity 33. The heat exchange tube bundle 32 is located in the heat exchange cavity 33. The cylinder body 31 is provided with the heat exchange inlet 311, the heat exchange outlet 312, an air inlet 313, and an air outlet 314. The heat exchange cavity 33 is communicated with the air inlet 313 and the air outlet 314. The heat exchange tube bundle 32 is communicated with the heat exchange inlet 311 and the heat exchange outlet 312.

[0042] For the convenience of description, the first heat exchanger 3a is taken as an example for description, in which the first heat exchanger 3a is communicated with the gas discharge pipe 2 and the second heat exchanger 3b.

[0043] Thus, one end of the gas discharge pipe 2 communicates with the fluidized bed 200, and the other end communicates with the air inlet 313 of the first heat exchanger 3a to send the reacted mixed gas into the heat exchange chamber 33. The air outlet 314 of the first heat exchanger 3a communicates with the second heat exchanger 3b, and the SiCl 4 liquid pipe 41 is connected to the heat exchange inlet 311 of the first heat exchanger 3a, and the heat exchange outlet 312 of the first heat exchanger 3a is connected to the SiCl 4 vaporizer 42, and the SiCl 4 gas pipe 43 is connected to the fluidized bed 200. With such a structure, the heat of the mixed gas sent into the heat exchange chamber 33 is used to preheat the SiCl 4 liquid in the heat exchange tube bundle 32.

[0044] The mixed gas discharged from the air outlet 314 of the first heat exchanger 3a enters the heat exchange chamber 33 of the second heat exchanger 3b from the air inlet 313 of the second heat exchanger 3b. One section of the H 2 pipe 11 is connected to the heat exchange inlet 311 of the second heat exchanger 3b, and the other end of one section is connected to the heat exchange outlet 312 of the second heat exchanger 3b, and the other end of the other section is connected to the fluidized bed 200.

[0045] Preferably, the heat exchange tube bundle 32 extends along the axial direction of the cylinder body 31, thereby improving the heat exchange efficiency.

[0046] In summary, for the silicon removal system 100 of the graphite cylinder of the fluidized bed 200 in the present application, through the SiCl 4 feeding device, SiCl 4 gas is injected into the fluidized bed 200, and the H 2 pipe 11 injects H 2 into the fluidized bed 200, so that SiCl 4 , H 2 react with the silicon attached to the inner wall of the graphite cylinder to generate chlorosilane, and the reaction formula is: H 2 +SiCl 4 +Si→SiH 3Cl. Thus, by the principle of the hydrogenation process, the silicon deposits adhering to the inner wall of the graphite cylinder are removed. Not only is the silicon removal effect good, realizing automated silicon removal, but also compared with manual mechanical silicon removal, the silicon removal efficiency and production efficiency are greatly improved, the silicon removal uniformity is enhanced, labor is saved, physical damage to the graphite cylinder caused by mechanical silicon removal is avoided, the service life of the graphite cylinder is prolonged, the equipment maintenance cost is reduced, and the silicon removal operation can be carried out without disassembling the graphite cylinder, reducing the equipment downtime and improving the production continuity. Further, the waste heat generated in the hydrogenation reaction can be recovered and utilized through the heat exchanger group for preheating the SiCl 4 、H 2 injected into the fluidized bed 200, improving the energy utilization rate.

[0047] The structure, features and effects of the present application have been described in detail based on the embodiments shown in the drawings. The above are only the preferred embodiments of the present application, but the present application is not limited to the scope defined by the drawings. Any changes made in accordance with the concept of the present application, or equivalent embodiments modified into equivalent changes, still within the spirit covered by the specification and drawings, shall be within the protection scope of the present application.

Claims

1. A desiliconization system for a fluidized bed graphite cylinder, wherein the graphite cylinder is located in the fluidized bed, characterized in that: The desiliconization system includes a SiCl4 supply device for injecting SiCl4 gas into the fluidized bed, an H2 pipeline for injecting H2 into the fluidized bed, a gas exhaust pipeline, and a heat exchanger group. The gas exhaust pipeline connects the fluidized bed and the heat exchanger group. The heat exchanger group includes at least two heat exchangers. The SiCl4 supply device and the H2 pipeline are respectively connected to the heat exchanger group to exchange heat.

2. The desiliconization system for fluidized bed graphite cylinder according to claim 1, characterized in that: The at least two heat exchangers include a first heat exchanger and a second heat exchanger, the first heat exchanger and the second heat exchanger are arranged in series, the SiCl4 supply device is connected to the first heat exchanger, and the H2 pipeline is connected to the second heat exchanger.

3. The desiliconization system for fluidized bed graphite cylinder according to claim 2, characterized in that: The SiCl4 supply device includes a SiCl4 liquid pipeline, a SiCl4 vaporizer and a SiCl4 gas pipeline connected in sequence, the SiCl4 liquid pipeline is connected to the heat exchange inlet of the first heat exchanger, the heat exchange outlet of the first heat exchanger is connected to the SiCl4 vaporizer, and the SiCl4 gas pipeline is connected to the fluidized bed.

4. The desiliconization system for fluidized bed graphite cylinder according to claim 2, characterized in that: The second heat exchanger is located downstream of the first heat exchanger.

5. The desiliconization system for fluidized bed graphite cylinder according to claim 2, characterized in that: The desiliconization system further includes an HCl pipeline for injecting HCl gas into the fluidized bed. The at least two heat exchangers further include a third heat exchanger, and the HCl pipeline is connected to the third heat exchanger.

6. The desiliconization system for fluidized bed graphite cylinder according to claim 5, characterized in that: The first heat exchanger, the second heat exchanger and the third heat exchanger are arranged in series.

7. The desiliconization system for fluidized bed graphite cylinder according to claim 6, characterized in that: The first heat exchanger is communicated with the gas exhaust pipeline, and the second heat exchanger is connected to the first heat exchanger and the third heat exchanger.

8. The desiliconization system for fluidized bed graphite cylinder according to claim 1, characterized in that: The desiliconization system also includes a gas-liquid separation device, a chlorosilane collection tank and an exhaust pipe connected to the heat exchanger group. The gas-liquid separation device is located downstream of the heat exchanger group, and the chlorosilane collection tank and the exhaust pipe are respectively connected to the gas-liquid separation device.

9. The desiliconization system for fluidized bed graphite cylinder according to claim 8, characterized in that: The gas-liquid separation device comprises a water-cooled jacket heat exchanger and a gas-liquid separation tank, the heat exchanger group is sequentially connected to the water-cooled jacket heat exchanger and the gas-liquid separation tank, and the chlorosilane collection tank and the exhaust pipe are respectively connected to the gas-liquid separation tank.

10. The desiliconization system for fluidized bed graphite cylinder according to claim 1, characterized in that: The heat exchanger includes a cylinder and a heat exchange tube bundle, the cylinder surrounds a heat exchange cavity, the heat exchange tube bundle is located in the heat exchange cavity, the cylinder is provided with a heat exchange inlet, a heat exchange outlet, an air inlet and an air outlet, the heat exchange cavity is connected to the air inlet and the air outlet, and the heat exchange tube bundle is connected to the heat exchange inlet and the heat exchange outlet.

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