Heat exchanger and heat exchange system

Abstract

The utility model provides a heat exchanger and a heat exchange system, and relates to the technical field of polycrystalline silicon production. The heat exchanger comprises a shell, a tube nest, a fixing plate, a floating assembly, an end cover, a baffle and a coating piece. The shell is provided with a cavity with two open ends. And the end cover covers the opening of the cavity. The tube nest, the fixing plate, the floating assembly and the baffle are all located in the cavity. The first end of the tube nest is connected with the shell through the fixing plate, and the second end of the tube nest is connected with the floating assembly. A gap is formed between the floating assembly and the shell. And a coating piece is arranged on the inner peripheral wall of the second end of the tube nest. And a shell feeding hole communicated with the cavity is formed in the shell. The baffle is connected with the inner circumferential wall of the shell. The orthographic projection of the baffle on the face, provided with the shell feeding port, of the shell covers the shell feeding port. According to the heat exchanger, the problem that the welding position of the tube nest and the tube plate of a heat exchanger of a traditional structure is prone to breakage is solved, the service life of the heat exchanger is prolonged, and the use performance of a heat exchange system is improved.

Description

Technical Field

[0001] The present application relates to the technical field of polysilicon production, and in particular to a heat exchanger and a heat exchange system. Background Art

[0002] At present, high-purity polysilicon of solar or electronic grade is often obtained through the modified Siemens process. The mainstream technologies of the modified Siemens production process include: first, silicon tetrachloride, hydrogen, hydrogen chloride and industrial silicon are reacted in a fluidized bed reactor as raw materials, and the generated mixed gas is separated by a condensation system to obtain hydrogen and a mixed liquid composed of trichlorosilane generated by the reaction, unreacted silicon tetrachloride, etc., and the hydrogen returns to the system to participate in the reaction again, and the mixed liquid is separated by distillation to obtain high-purity trichlorosilane (silicon tetrachloride is recycled after purification); then, the vaporized trichlorosilane and hydrogen are mixed in a certain proportion and introduced into the polysilicon reduction furnace, and voltage is applied to both ends of the rod-shaped silicon core placed in the reduction furnace to generate high temperature. On the surface of the high-temperature silicon core, trichlorosilane is reduced to elemental silicon by hydrogen and deposited on the surface of the silicon core, gradually generating polysilicon rods of the required specifications.

[0003] In the prior art, silicon tetrachloride, hydrogen, hydrogen chloride and industrial silicon are reacted in a fluidized bed reactor as raw materials, and the generated mixed gas enters the cold hydrogenation reaction heat exchange system. The cold hydrogenation reaction heat exchange system is a key link in the utilization of heat energy in the cold hydrogenation process. The cold hydrogenation reaction heat exchange system includes multiple heat exchangers. The high-temperature mixed gas passes through 2 to 4 heat exchangers to transfer heat to the raw gas, heat the raw gas, and then reduce the temperature of the mixed gas generated by the reaction. The heat exchanger includes a shell, tubes and tube sheets. The shell has a cavity, the tubes and tube sheets are both located in the cavity, the tubes are welded to the tube sheets, and the tube sheets are connected to the inner periphery of the shell. The mixed gas generated by the reaction enters and exits from the top and bottom in the tubes of the heat exchanger, and the raw gas enters and exits from the bottom and top in the cavity of the shell of the heat exchanger.

[0004] However, the existing heat exchanger has the problem that the welding points between the tubes and the tube sheets are prone to breakage. Utility Model Content

[0005] The present application provides a heat exchanger and a heat exchange system, which avoids the problem of easy breakage at the welding points of the tubes and tube sheets of a traditional heat exchanger, increases the service life of the heat exchanger, and improves the performance of the heat exchange system.

[0006] In a first aspect, the present application provides a heat exchanger, comprising a shell, a tube, a fixed plate, a floating assembly, an end cover, a baffle and a coating member. The shell has a cavity with two ends open. The end cover covers the opening of the cavity. The tube, the fixed plate, the floating assembly and the baffle are all located in the cavity. The first end of the tube is connected to the shell through the fixed plate, and the second end of the tube is connected to the floating assembly. There is a gap between the floating assembly and the shell. The inner peripheral wall of the second end of the tube is provided with a coating member.

[0007] The shell is provided with a shell feed inlet connected to the cavity. The baffle is connected to the inner peripheral wall of the shell. The orthographic projection of the baffle on the surface of the shell where the shell feed inlet is provided covers the shell feed inlet.

[0008] In the above heat exchanger, optionally, the first end of the baffle is connected to the inner peripheral wall of the shell, and the second end of the baffle extends toward the tube array.

[0009] Along the first end to the second end of the baffle, the included angle between the extension direction of the baffle and the direction from the first end to the second end of the shell is greater than or equal to 30° and less than or equal to 80°.

[0010] In the above heat exchanger, optionally, the baffle includes a first plate segment, a second plate segment, and a third plate segment connected in sequence. The first plate segment extends from the first end of the shell to the second end of the shell, and is connected to the inner peripheral wall of the shell. The third plate segment extends from the first end of the shell to the second end of the shell, and is connected to the tube array. The extension direction of the second plate segment intersects with the extension directions of the first plate segment and the third plate segment.

[0011] In the above heat exchanger, optionally, the floating assembly includes a floating plate and a floating cover. The floating plate is connected to the second end of the tube array. There is a gap between the floating plate and the inner peripheral wall of the shell.

[0012] The floating cover is arranged at the end of the floating plate away from the tube array, and the floating cover is connected to the floating plate.

[0013] In the above heat exchanger, optionally, it further comprises a sleeve, which is sleeved inside the tube array, and the sleeve is threadedly connected or clamped to the second end of the tube array.

[0014] Along the direction from the first end to the second end of the tube array, the extension length of the sleeve is greater than the extension length of the floating plate.

[0015] In the above heat exchanger, optionally, an expansion joint is further included. The expansion joint is arranged at the second end of the shell and is connected to the outer periphery of the shell through a flange.

[0016] In the above heat exchanger, optionally, a blocking net is further included. The blocking net is arranged at the first end of the shell and covers the opening at the first end of the shell. The blocking net is located between the end cover and the fixing plate, and the blocking net is connected to the inner peripheral wall of the shell.

[0017] In the above heat exchanger, optionally, the coating member includes at least one of a tungsten carbide coating, a zirconium oxide coating, an aluminum oxide coating, and a chromium coating.

[0018] In the above heat exchanger, optionally, the inner peripheral wall of the shell, the outer peripheral wall of the tube array, the fixed plate, and the outer peripheral wall of the floating cover surround a shell cavity. The shell is provided with a shell feed port and a shell discharge port connected to the shell cavity.

[0019] The tube cavity, the end cover, the inner peripheral wall of the floating cover and the fixed plate of the tube array form a tube cavity. The end cover is respectively provided with a tube feed port and a tube discharge port connected with the tube cavity.

[0020] And / or, there are multiple tubes, multiple first fixing holes are set on the fixed plate, and multiple first fixing holes are correspondingly penetrated at the first ends of the multiple tubes; multiple second fixing holes are set on the floating plate, and multiple second fixing holes are correspondingly penetrated at the second ends of the multiple tubes.

[0021] In a second aspect, the present application provides a heat exchange system, comprising a reactor, a quench tower and a plurality of heat exchangers, wherein the plurality of heat exchangers are connected end to end in sequence. The reactor is connected to a pipe body feed port of the heat exchanger located at the head. The quench tower is connected to a pipe body discharge port of the heat exchanger located at the tail.

[0022] The present application provides a heat exchanger and a heat exchange system, wherein the heat exchanger includes a shell, a tube, a fixed plate, a floating assembly, an end cover, a baffle and a coating member. The end cover covers the opening of the shell cavity. The tubes, the fixed plate, the floating assembly and the baffle are all located in the shell cavity. The shell is provided with a shell feed port connected to the cavity. The first end of the tube is connected to the shell through the fixed plate, and the second end of the tube is connected to the floating assembly. By providing a gap between the floating assembly and the shell, the second end of the tube can move in the shell cavity, releasing the force between the tube and the floating assembly, and between the floating assembly and the shell, which helps to extend the service life of the heat exchanger and improve the performance of the heat exchange system. By providing a coating member on the inner peripheral wall of the second end of the tube, the precipitation speed of the material in the tube at the second end of the tube is slowed down. By setting a baffle, connecting the baffle to the inner peripheral wall of the shell, and setting the orthographic projection of the baffle on the surface of the shell with the shell feed port to cover the shell feed port, the baffle can change the flow direction of the cavity material at the shell feed port, prevent the cavity material from directly flowing to the second end of the array tube, reduce the temperature difference between the second end of the array tube and the cavity material, and prevent the material in the array tube from precipitating at the second end of the array tube. The heat exchange system provided by the present application includes a heat exchanger, which improves the performance of the heat exchange system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0024] Figure 1 A schematic diagram of the structure of a heat exchanger provided in an embodiment of the present application;

[0025] Figure 2 Schematic diagram of the local structure of the heat exchanger provided in the embodiment of the present application Figure 1 ;

[0026] Figure 3 Schematic diagram of the local structure of the heat exchanger provided in the embodiment of the present application Figure 2 .

[0027] Description of reference numerals:

[0028] 100: shell; 110: shell inlet; 120: shell outlet;

[0029] 200: Listed;

[0030] 300: fixed plate;

[0031] 400: floating assembly; 410: floating plate; 420: floating cover;

[0032] 500: end cap; 510: tube body feed port; 520: tube body discharge port;

[0033] 600: baffle; 610: first plate segment; 620: second plate segment; 630: third plate segment;

[0034] 700: coated parts;

[0035] 800: blocking net;

[0036] 900: expansion joint;

[0037] 1000: shell cavity; 2000: tube cavity.

[0038] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0039] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0040] Polysilicon is the main raw material for manufacturing integrated circuit substrates, solar cells and other products. Polysilicon deep-processing products are widely used in the semiconductor industry as the basic material for devices such as artificial intelligence, automatic control, information processing, and photoelectric conversion.

[0041] In industrial applications, high-purity polysilicon of solar or electronic grade is currently often obtained through the modified Siemens process. The mainstream technologies of the modified Siemens production process include: first, silicon tetrachloride, hydrogen, hydrogen chloride and industrial silicon are reacted in a fluidized bed reactor as raw materials, and the generated mixed gas is separated through a condensation system to obtain hydrogen and a mixed liquid composed of trichlorosilane generated by the reaction, unreacted silicon tetrachloride, etc., the hydrogen returns to the system to participate in the reaction again, and the mixed liquid is separated by distillation to obtain high-purity trichlorosilane (silicon tetrachloride is recycled after purification); then, the vaporized trichlorosilane and hydrogen are mixed in a certain proportion and introduced into a polysilicon reduction furnace, and voltage is applied to both ends of the rod-shaped silicon core placed in the reduction furnace to generate high temperature. On the surface of the high-temperature silicon core, trichlorosilane is reduced to elemental silicon by hydrogen and deposited on the surface of the silicon core, gradually generating polysilicon rods of the required specifications.

[0042] In the prior art, the mixed gas after the reaction in the fluidized bed reactor enters the cold hydrogenation reaction heat exchange system to be cooled step by step and then enters the cold hydrogenation reaction condensation system. The circulating hydrogen separated in the condensation system is mixed with the supplementary hydrogen from the outside and then enters the hydrogen preheating system. The chlorosilane liquid cooled by the condensation system enters the cold hydrogenation rough separation system, where it is preliminarily separated. The separated crude trichlorosilane product is sent to the subsequent device for distillation. The separated circulating silicon tetrachloride and the silicon tetrachloride supplemented from the outside enter the silicon tetrachloride preheating system together. The preheated hydrogen and silicon tetrachloride enter the silicon tetrachloride / hydrogen mixed vaporization system together for mixing and vaporization. The mixed silicon tetrachloride and hydrogen enter the heat exchange system and are heated step by step before entering the fluidized bed reactor to react again. In this process, the cold hydrogenation reaction heat exchange system is a key link in the utilization of heat energy in the cold hydrogenation unit. The high-temperature (520-560°C) mixed gas passes through the tube side of the 2-4-stage heat exchanger to transfer heat to the raw gas in the shell side - hydrogen and silicon tetrachloride mixed gas, heating the hydrogen and silicon tetrachloride mixed gas to 470-510°C, and reducing the temperature of the mixed gas to 210-250°C. After the heat of the mixed gas is fully recovered, it enters the subsequent washing section for washing and dust removal.

[0043] The heat exchanger is a vertical shell and tube heat exchanger. The heat exchanger includes a shell, a tube and a tube sheet. The shell has a cavity, and the tubes and the tube sheet are both located in the cavity. The tubes are welded to the tube sheet, and the tube sheet is connected to the inner periphery of the shell. The tubes of the heat exchanger are 5-12 meters long. The mixed gas generated by the reaction enters the heat exchanger from the top and exits from the bottom, and the raw gas enters the heat exchanger from the bottom and exits from the top in the cavity of the shell.

[0044] However, the temperature difference on one side of the heat exchanger is about 90-150℃, which is a large temperature difference. Thermal stress is inevitably generated between the shell and the tube sheet. In addition, the temperature of the raw gas entering the shell is in the range of 160-175℃, and the wall temperature at the bottom of the tube is close to the temperature of the raw gas. The mixed gas in the tube may precipitate metal chlorides at the bottom of the tube, and the metal chlorides adhere to the tube wall and corrode the tube wall. Under the multiple effects of thermal stress and precipitation, the heat exchanger has the problem of easy fracture at the welding point between the tube and the tube sheet.

[0045] In view of this, an embodiment of the present application provides a heat exchanger and a heat exchange system, wherein the heat exchanger includes a shell, a tube, a fixed plate, a floating assembly, an end cover, a baffle and a coating member. The end cover covers the opening of the shell cavity. The tubes, the fixed plate, the floating assembly and the baffle are all located in the shell cavity. The shell is provided with a shell feed port connected to the cavity. The first end of the tube is connected to the shell through the fixed plate, and the second end of the tube is connected to the floating assembly. By setting a gap between the floating assembly and the shell, the second end of the tube can move in the shell cavity, releasing the force between the tube and the floating assembly, and between the floating assembly and the shell, which helps to extend the service life of the heat exchanger and improve the performance of the heat exchange system. By setting a coating member on the inner peripheral wall of the second end of the tube, the precipitation speed of the material in the tube at the second end of the tube is slowed down. By setting a baffle, connecting the baffle to the inner peripheral wall of the shell, and setting the orthographic projection of the baffle on the surface of the shell with the shell feed port to cover the shell feed port, the baffle can change the flow direction of the cavity material at the shell feed port, prevent the cavity material from directly flowing to the second end of the array tube, reduce the temperature difference between the second end of the array tube and the cavity material, and prevent the material in the array tube from precipitating at the second end of the array tube. The heat exchange system provided by the present application includes a heat exchanger, which improves the performance of the heat exchange system.

[0046] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0047] Figure 1 The structural diagram of the heat exchanger provided in the embodiment of the present application is schematically shown. Figure 2 A schematic diagram of the partial structure of the heat exchanger provided in an embodiment of the present application is schematically shown.

[0048] First, refer to Figure 1 and Figure 2As shown, the present application provides a heat exchanger. The heat exchanger includes a shell 100, a tube array 200, a fixed plate 300, a floating assembly 400, an end cover 500, a baffle 600 and a coating member 700. The shell 100 has a cavity with openings at both ends. The end cover 500 covers the opening of the cavity. The tube array 200, the fixed plate 300, the floating assembly 400 and the baffle 600 are all located in the cavity. The first end of the tube array 200 is connected to the shell 100 through the fixed plate 300, and the second end of the tube array 200 is connected to the floating assembly 400. There is a gap between the floating assembly 400 and the shell 100. The inner peripheral wall of the second end of the tube array 200 is provided with a coating member 700.

[0049] The housing 100 is provided with a housing feed inlet 110 communicating with the cavity. The baffle 600 is connected to the inner peripheral wall of the housing 100. The baffle 600 is projected on the surface of the housing 100 where the housing feed inlet 110 is provided, and covers the housing feed inlet 110.

[0050] For example, material A flows in the tube array 200. Material A flows from the first end of the tube array 200 to the second end of the tube array 200. Material B enters the cavity through the shell feed port 110. The shell feed port 110 is located at the bottom end of the shell 100. Material A is a high-temperature material. Material B is a low-temperature material.

[0051] During the use of the heat exchanger, the low-temperature material B enters from the shell feed port 110 located at the bottom of the shell 100. At the same time, under the action of the baffle 600, the flow direction of the low-temperature material B is changed, and the low-temperature material B flows to the top of the shell 100. At the same time, the high-temperature material A flows into the tubes 200 of the heat exchanger, and flows from the first end of the tubes 200 to the second end of the tubes 200. Among them, the first end of the tubes 200 is the top of the tubes 200, and the second end of the tubes 200 is the bottom of the tubes 200. By setting a baffle 600 at the position of the shell feed port 110, the baffle 600 is connected to the inner peripheral wall of the shell 100, and the orthographic projection of the baffle 600 on the surface of the shell 100 where the shell feed port 110 is opened is set to cover the shell feed port 110, the baffle 600 changes the flow direction and path of the low-temperature material B, thereby guiding the material B to flow inside the cavity according to the design requirements, preventing the low-temperature material B from directly scouring the second end of the array tube 200, and preventing the high-temperature material A from precipitating at the second end of the array tube 200 and corroding the array tube 200. At the same time, the baffle 600 can reduce the impact of the low-temperature material B on the second end of the array tube 200, and prevent the array tube 200 from being separated from the floating plate assembly under multiple forces.

[0052] For example, when the high-temperature material A generates precipitates at the second end of the low-temperature tube 200, the precipitates adhere to the inner circumferential wall of the tube 200, exerting a downward force on the second end of the tube 200. At the same time, the second end of the tube 200 contains the high-temperature material A inside and the low-temperature material B outside. Thermal stress exists at the connection between the tube 200 and the floating assembly 400. By setting a gap between the floating assembly 400 and the shell 100, when the tube 200 is subjected to thermal stress and the downward force exerted by the precipitates, the floating assembly 400 can drive the tube 200 to move to release the force, reduce the influence of multiple forces on the heat exchanger, and extend the service life of the heat exchanger.

[0053] For example, when the high-temperature material A generates precipitates at the second end of the low-temperature tube 200, the precipitates adhere to the inner circumferential wall of the tube 200. By arranging the coating member 700 at the second end of the tube 200, the coating member 700 can form a protective film inside the tube 200, improve the smoothness of the surface of the tube 200, and improve the corrosion resistance of the surface of the tube 200. The coating member 700 can make the inner surface of the tube 200 smoother, reduce the adhesion of precipitates, avoid corrosion of the tube 200, and reduce the frequency of cleaning and maintenance. Extend the service life of the heat exchanger.

[0054] As a feasible implementation, the coating member 700 includes at least one of a tungsten carbide coating, a zirconium oxide coating, an aluminum oxide coating, and a chromium coating.

[0055] For example, the coating member 700 is disposed on the inner circumferential wall of the second end of the tube 200, and the coating member 700 can make the inner circumferential wall of the second end of the tube 200 smooth to prevent the precipitate generated by the material A at the second end of the tube 200 from adhering to the tube 200. At the same time, the coating member 700 has an anti-corrosion effect to prevent the precipitate from corroding the second end of the tube 200 and reducing the service life of the tube 200.

[0056] For example, the coated part 700 can be a tungsten carbide coating, which has high hardness and wear resistance; the coated part 700 can also be a zirconium oxide coating, which has high temperature stability and chemical inertness; the coated part 700 can also be an aluminum oxide coating, which has corrosion resistance; the coated part 700 can also be a chromium coating, which has good corrosion resistance.

[0057] For example, the coating member 700 may be a single-layer coating. Specifically, the coating is a tungsten carbide coating.

[0058] For example, the coating member 700 may also be a multi-layer composite layer. Specifically, the coating member 700 is a composite coating formed by a chromium coating layer and a tungsten carbide coating layer.

[0059] Figure 3A schematic diagram of the partial structure of the heat exchanger provided in an embodiment of the present application is schematically shown.

[0060] As a feasible implementation method, refer to Figure 3 As shown, the floating assembly 400 includes a floating plate 410 and a floating cover 420. The floating plate 410 is connected to the second end of the tube 200. There is a gap between the floating plate 410 and the inner circumferential wall of the shell 100. During the use of the heat exchanger, the low-temperature material B impacts the floating plate 410, and the connection between the tube 200 and the floating plate 410 has thermal stress. At the same time, material A may generate precipitates at the second end of the tube 200. By setting a gap between the floating plate 410 and the shell 100, when the tube 200 is subjected to thermal stress and the downward force exerted by the precipitate, the floating plate 410 can drive the tube 200 to move to release the force, reduce the impact of multiple forces on the heat exchanger, and extend the service life of the heat exchanger.

[0061] For example, the second ends of the tubes 200 are welded to the floating plate 410 .

[0062] As an achievable implementation, the inner circumferential wall of the shell 100, the outer circumferential wall of the tube array 200, the fixed plate 300, and the outer circumferential wall of the floating cover 420 surround the shell cavity 1000. The shell 100 is provided with a shell feed port 110 and a shell discharge port 120 communicating with the shell cavity 1000.

[0063] The tube cavity 200 of the tube array 200, the end cover 500, the inner peripheral wall of the floating cover 420 and the fixed plate 300 surround a tube cavity 2000. The end cover 500 is provided with a tube feed port 510 and a tube discharge port 520 communicating with the tube cavity 2000.

[0064] For example, the shell 100 has a cavity with two ends open, and two end covers 500 are respectively covered at the openings. The two end covers 500 are respectively provided with a tube body feed port 510 and a tube body discharge port 520. In addition, the shell 100 is also provided with a shell feed port 110 and a shell discharge port 120. In the cavity of the shell 100, the array tubes 200 extend along the extension direction of the cavity of the shell 100. The two ends of the array tubes 200 are respectively provided with a fixed plate 300 and a floating plate 410. The first end of the array tube 200 is welded to the fixed plate 300, and the fixed plate 300 is welded to the shell 100. The second end of the array tube 200 is welded to the floating plate 410, and there is a gap between the floating plate 410 and the shell 100. The floating cover 420 is provided at the end of the floating plate 410 away from the array tube 200, and the floating cover 420 is connected to the floating plate 410. Among them, the inner circumferential wall of the shell 100, the outer circumferential wall of the array tube 200, the fixed plate 300 and the outer circumferential wall of the floating cover 420 surround a shell cavity 1000, and the array tube cavity of the array tube 200, the end cover 500, the inner circumferential wall of the floating cover 420 and the fixed plate 300 surround a tube body cavity 2000.

[0065] It can be understood that there are multiple tubes 200, and the fixed plate 300 is provided with multiple first fixing holes, and the first ends of the multiple tubes 200 are correspondingly penetrated through the multiple first fixing holes on the fixed plate 300, so as to realize the simultaneous feeding of the multiple tubes 200. The floating plate 410 is provided with multiple second fixing holes, and the second ends of the multiple tubes 200 are correspondingly penetrated through the multiple second fixing holes.

[0066] In some embodiments, the heat exchanger is a vertical tube-and-tube 200 type heat exchanger. Figure 1 The material A enters from the tube body feed port 510 of the top end cap 500. At this time, the material A enters the tube body cavity 2000. Then the material A enters the array tube 200 and flows along the Figure 1 The material A moves in the direction of the black solid arrow. After flowing out of the tube array 200, it leaves the heat exchanger from the tube body outlet 520. While the material A enters the tube body cavity 2000 from the tube body feed port 510, the material B enters the shell cavity 1000 from the shell feed port 110 near the bottom. The material B moves along the black hollow arrow and then leaves the shell cavity 1000 from the shell outlet 120.

[0067] By setting material A to enter from the tube body feed port 510 of the top end cover 500 and to flow out from the tube body discharge port 520 of the bottom end cover 500, and setting material B to enter from the bottom shell feed port 110 and to flow out from the top shell discharge port 120, material B enters the heat exchanger from below, rises along the heat exchange surface, and flows in the opposite direction to material A. This countercurrent method maximizes the use of the heat exchange surface, increases the heat exchange effect, and is beneficial to improving the heat exchange efficiency.

[0068] It can be understood that a baffle is also provided in the cavity of the shell 100, and the baffle is connected to the shell 100. The baffle is located between the shell feed port 110 and the shell discharge port 120 to change the flow direction and path of the material B, so that the material B forms turbulence or eddy inside the heat exchanger, thereby increasing the contact between the material B and the heat exchange surface and improving the heat transfer efficiency.

[0069] As an achievable implementation, the heat exchanger further includes an expansion joint 900. The expansion joint 900 is disposed at the second end of the shell 100. The expansion joint 900 is connected to the outer periphery of the shell 100 via a flange.

[0070] For example, the temperature difference between the material A flowing in the tubes and the material B flowing in the shell cavity 1000 is the largest at the second end of the tubes 200, so the expansion joint 900 is arranged at the bottom end of the shell 100 of the heat exchanger. The expansion joint 900 is arranged at the bottom end of the shell 100, so that the expansion joint 900 can be more easily adjusted for thermal expansion and contraction to adapt to the deformation of the shell 100 caused by temperature changes during the operation of the heat exchanger. The expansion joint 900 is connected to the outer periphery of the shell 100 through a flange. This connection method can ensure the sealing and stability between the expansion joint 900 and the shell 100, and also facilitate the installation and maintenance of the expansion joint 900.

[0071] As an achievable implementation, the first end of the baffle 600 is connected to the inner circumferential wall of the shell 100 to ensure that the baffle 600 is firmly fixed inside the shell 100 without loosening or displacement. The second end of the baffle 600 extends toward the tube array 200 to change the flow direction of the material B.

[0072] Along the first end to the second end of the baffle 600 , the included angle between the extension direction of the baffle 600 and the direction from the first end to the second end of the shell 100 is greater than or equal to 30° and less than or equal to 80°.

[0073] For example, the first end of the housing 100 is the top end of the housing 100 , and the second end of the housing 100 is the bottom end of the housing 100 .

[0074] When the angle between the extension direction of the baffle 600 and the direction from the first end of the shell 100 to the second end of the shell 100 is less than 30°, the baffle 600 can change the flow direction of the low-temperature material B entering from the shell feed port 110. However, since the angle between the extension direction of the baffle 600 and the direction from the first end of the shell 100 to the second end of the shell 100 is too small, the space between the baffle 600 and the shell feed port 110 is limited, and part of the material B will bounce off the shell feed port 110 at the baffle 600, reducing the feeding speed of the material B and reducing the heat exchange efficiency of the heat exchanger.

[0075] When the angle between the extension direction of the baffle 600 and the direction from the first end of the shell 100 to the second end of the shell 100 is greater than 80°, the baffle 600 can change the flow direction of the low-temperature material B that partially enters from the shell feed port 110. However, due to the large angle between the extension direction of the baffle 600 and the direction from the first end to the second end of the shell 100, part of the low-temperature material B will still impact the second end of the tube array 200, increasing the probability that the high-temperature material A will generate precipitates at the second end of the tube array 200.

[0076] When the angle between the extension direction of the baffle 600 and the direction from the first end of the shell 100 to the second end of the shell 100 is greater than or equal to 30° and less than or equal to 80°, the baffle 600 effectively guides the material B to flow into the cavity, reduces the rebound of the baffle 600 on the material B, avoids the loss of the material B, and improves the heat exchange efficiency. Therefore, the present application sets the angle between the extension direction of the baffle 600 and the direction from the first end of the shell 100 to the second end of the shell 100 to be greater than or equal to 30° and less than or equal to 80°.

[0077] As an achievable implementation, the baffle 600 includes a first plate segment 610, a second plate segment 620, and a third plate segment 630 connected in sequence. The first plate segment 610 extends from the first end of the shell 100 to the second end of the shell 100, and is connected to the inner peripheral wall of the shell 100. The third plate segment 630 extends from the first end of the shell 100 to the second end of the shell 100, and is connected to the tube array 200. The extension direction of the second plate segment 620 intersects with the extension directions of the first plate segment 610 and the third plate segment 630.

[0078] For example, by setting the extension direction of the first plate segment 610 to be consistent with the direction from the first end of the shell 100 to the second end of the shell 100, and connecting the first plate segment 610 to the inner circumferential wall of the shell 100, the connection area between the first plate segment 610 and the inner circumferential wall of the shell 100 is increased. By setting the extension direction of the third plate segment 630 to be consistent with the direction from the first end of the shell 100 to the second end of the shell 100, and connecting the third plate segment 630 to the tube 200, the connection area between the third plate segment 630 and the outer circumferential wall of the tube 200 is increased. The extension direction of the second plate segment 620 intersects with the extension directions of the first plate segment 610 and the third plate segment 630, so as to change the flow direction of the material B. By setting the first plate segment 610 and the third plate segment 630, and setting the extension direction of the first plate segment 610 and the third plate segment 630 to be consistent with the direction from the first end to the second end of the shell 100, the connection strength between the baffle 600 and the shell 100 and the tube array 200 is improved, the damage of the baffle 600 under the impact of the material B is avoided, and the service life of the baffle 600 is improved.

[0079] As a feasible implementation, the heat exchanger further comprises a sleeve. The sleeve is sleeved inside the tube array 200, and the sleeve and the second end of the tube array 200 are threadedly connected or clamped.

[0080] For example, the sleeve and the second end of the tube 200 are threaded or clamped. The inner circumferential wall of the sleeve is provided with a coating member 700. This detachable connection between the sleeve and the tube 200 allows only the damaged sleeve to be disassembled and replaced after a large amount of precipitates are deposited on the sleeve on the inner circumferential wall of the second end of the tube 200, thereby improving the convenience of heat exchanger maintenance and repair, reducing maintenance costs, and increasing the service life of the heat exchanger. Along the direction from the first end of the tube 200 to the second end of the tube 200, the extension length of the sleeve is greater than the extension length of the floating plate 410. In this way, the sleeve can better withstand the pressure and load of the material A, increase the strength and stability of the structure, reduce deformation and vibration, and increase the service life of the heat exchanger.

[0081] As an achievable implementation, the heat exchanger further includes a blocking net 800. The blocking net 800 is disposed at the first end of the shell 100 and covers the opening at the first end of the shell 100. The blocking net 800 is located between the end cover 500 and the fixing plate 300, and the blocking net 800 is connected to the inner peripheral wall of the shell 100.

[0082] For example, the blocking net 800 is provided with a plurality of holes, and the material A enters the tube body cavity 2000 through the holes. The blocking net 800 plays the role of isolation and filtration, preventing impurities or particulate matter from entering the heat exchanger, reducing the dirt and impurity blockage inside the heat exchanger, and keeping the surface of the heat exchanger clean, which is conducive to the transfer of heat and the improvement of heat exchange efficiency. At the same time, by setting the blocking net 800, the staff can replace the blocking net 800 regularly, reducing the cleaning frequency and maintenance cost inside the heat exchanger, and reducing the operating cost of the heat exchanger.

[0083] In a second aspect, the present application provides a heat exchange system, including a reactor, a quench tower and a plurality of heat exchangers, wherein the plurality of heat exchangers are connected end to end in sequence. The reactor is connected to a pipe body feed port 510 of the heat exchanger located at the head. The quench tower is connected to a pipe body discharge port 520 of the heat exchanger located at the tail.

[0084] For example, in the production process of polysilicon, in the early cold hydrogenation reaction, hydrogen and silicon tetrachloride gas enter the reactor through the distributor, and are fully mixed with the silicon powder in the reactor for gas-solid phase synthesis reaction to generate trichlorosilane, and at the same time generate byproducts such as silicon tetrachloride, dichlorodihydrosilane, metal chloride, polychlorosilane, etc. The mixed gas formed by trichlorosilane and these byproducts enters the head heat exchanger through the pipe body feed port 510 of the head heat exchanger, and passes through multiple heat exchangers in sequence, and finally enters the quenching tower through the pipe body discharge port 520 of the heat exchanger located at the tail. In the process of the mixed gas flowing in the array tubes 200 of multiple heat exchangers, the silicon tetrachloride and hydrogen mixed gas to be reacted or collected enters the shell cavity 1000 of the heat exchanger and enters the reactor for reaction again after being heated step by step. Through the above process, the heat transfer and cooling process can be effectively realized to ensure that the temperature and pressure of the material in the whole system are controlled and adjusted, so as to meet the process requirements and improve the energy utilization efficiency.

[0085] It is understandable that, since the heat exchange system of the present application adopts the technical solution of the above-mentioned heat exchanger embodiment, it at least has the beneficial effects brought by the technical solution of the above-mentioned embodiment, which will not be described one by one here.

[0086] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the application disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0087] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A heat exchanger, characterized in that: The invention comprises a shell, a tube array, a fixing plate, a floating assembly, an end cover, a baffle and a coating member; the shell has a cavity with two ends opened, and the end cover covers the openings of the cavity; the tube array, the fixing plate, the floating assembly and the baffle are all located in the cavity; the first end of the tube array is connected to the shell through the fixing plate, the second end of the tube array is connected to the floating assembly, and a gap is provided between the floating assembly and the shell; the inner peripheral wall of the second end of the tube array is provided with the coating member; The shell is provided with a shell feed port connected to the cavity, and the baffle is connected to the inner peripheral wall of the shell; the orthographic projection of the baffle on the surface of the shell on which the shell feed port is opened covers the shell feed port.

2. The heat exchanger according to claim 1, characterized in that: The first end of the baffle is connected to the inner peripheral wall of the shell, and the second end of the baffle extends toward the tube array; Along the first end to the second end of the baffle, the included angle between the extension direction of the baffle and the direction from the first end to the second end of the shell is greater than or equal to 30° and less than or equal to 80°.

3. The heat exchanger according to claim 1, characterized in that: The baffle includes a first plate segment, a second plate segment and a third plate segment connected in sequence, the first plate segment extends from the first end of the shell to the second end of the shell and is connected to the inner circumferential wall of the shell; the third plate segment extends from the first end of the shell to the second end of the shell and is connected to the tube array; the extension direction of the second plate segment intersects with the extension directions of the first plate segment and the third plate segment.

4. The heat exchanger according to claim 1, characterized in that: The floating assembly comprises a floating plate and a floating cover, the floating plate is connected to the second end of the tube array, and there is the gap between the floating plate and the inner peripheral wall of the shell; The floating cover is arranged at the end of the floating plate away from the tube array, and the floating cover is connected to the floating plate.

5. The heat exchanger according to claim 4, characterized in that: It also includes a sleeve, which is sleeved inside the tube array, and the sleeve is threadedly connected or clamped to the second end of the tube array; Along the direction from the first end of the tube array to the second end of the tube array, the extension length of the sleeve is greater than the extension length of the floating plate.

6. The heat exchanger according to any one of claims 1 to 5, characterized in that: It also includes an expansion joint, which is arranged at the second end of the shell and is connected to the outer periphery of the shell through a flange.

7. The heat exchanger according to any one of claims 1 to 5, characterized in that: It also includes a blocking net, which is arranged at the first end of the shell and covers the opening located at the first end of the shell; the blocking net is located between the end cover and the fixing plate, and the blocking net is connected to the inner peripheral wall of the shell.

8. The heat exchanger according to claim 7, characterized in that The coating component includes at least one of a tungsten carbide coating, a zirconium oxide coating, an aluminum oxide coating, and a chromium coating.

9. The heat exchanger according to claim 4, characterized in that: The inner circumferential wall of the shell, the outer circumferential wall of the tube array, the fixed plate, and the outer circumferential wall of the floating cover surround a shell cavity, and the shell is provided with a shell feed port and a shell discharge port connected to the shell cavity; The tube cavity of the tube array, the end cover, the inner peripheral wall of the floating cover and the fixed plate are surrounded to form a tube cavity, and the end cover is respectively provided with a tube feed port and a tube discharge port connected to the tube cavity; And / or, there are multiple tubes, multiple first fixing holes are arranged on the fixed plate, and multiple first fixing holes are correspondingly penetrated at the first ends of the multiple tubes; multiple second fixing holes are arranged on the floating plate, and multiple second fixing holes are correspondingly penetrated at the second ends of the multiple tubes.

10. A heat exchange system, characterized in that: It comprises a reactor, a quenching tower and a plurality of heat exchangers according to any one of claims 1 to 9, wherein the plurality of heat exchangers are connected end to end in sequence, the reactor is connected to the pipe body feed port of the heat exchanger located at the head, and the quenching tower is connected to the pipe body discharge port of the heat exchanger located at the tail.

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