Heat exchanger for tetra-chlorosilane vaporization

Abstract

The utility model belongs to heat exchanger technical field provides a four chlorosilane vaporization heat exchanger, include: upper head cylinder, upper tube plate, intermediate cylinder, lower tube plate and lower head cylinder, they are bolted and sealed connection in proper order, and a plurality of heat exchange pipes are in the form of equal interval annular array in intermediate cylinder, and the both ends of each heat exchange pipe are connected with upper tube plate and lower tube plate respectively and are communicated with upper head cylinder and lower head cylinder respectively, wherein, the radial of intermediate cylinder is equipped with shell side import and the shell side export below shell side import, the radial of upper head cylinder is equipped with tube side export, the axial of lower head cylinder is equipped with tube side import, the side of lower tube plate towards lower head cylinder is closely combined with the anti -impact board. The upper and lower tube plate that sets up is connected and fixed in the mode of bolted connection, is favorable to overhaul and replacement, and the anti -impact board is combined still on the side of lower tube plate that meets material, can separate lower tube plate and protect it, thereby avoiding the direct scouring and corrosion of tube side medium to lower tube plate, prolongs the service life of lower tube plate.

Description

Technical Field

[0001] This utility model relates to the field of heat exchanger technology, specifically to a heat exchanger for the vaporization of tetrachlorosilane. Background Technology

[0002] Currently, in the high-boiling point treatment process of polysilicon production slurry, tetrachlorosilane in the material needs to be heated and vaporized through a heat exchanger. After the high-boiling point is separated by a de-boiling tower, the tetrachlorosilane is then recovered and reused. The shell-side medium of this vaporization heat exchanger is 0.6 MPaG steam, and the tube-side medium is 0.14 MPaG tetrachlorosilane (containing high-boiling point and silicon powder), making this heat exchanger very important.

[0003] In practical use, existing heat exchangers have the following problems:

[0004] 1. The tube sheet on the inlet side of the tube side (medium) is not resistant to the erosion and wear of the medium, and the erosion marks are obvious. Moreover, the tube sheet is welded to the shell, and the outer ring of the tube sheet is used as the connecting flange of the shell, making maintenance and replacement extremely inconvenient.

[0005] 2. The connection between heat exchange tubes and tube sheets generally adopts the manufacturing process of "strength welding + expansion". The tube head protrudes slightly from the tube sheet to facilitate welding and form a fillet weld. The expansion process is prone to loose fit, leaving gaps between the outer wall of the tube and the tube sheet hole. The protruding tube head is easily eroded and worn by the medium, and the tube-side medium can seep into the shell side through the gap and undergo hydrolysis reaction with the shell-side medium, producing HCl, which further corrodes the fillet weld at the tube head. Moreover, the welding technology of fillet weld is high and the pass rate is low. In addition, the heat exchange tubes are made of 10# carbon steel, which is not wear-resistant or resistant to high-boiling tetrachlorosilane corrosion, leading to perforation of the heat exchange tubes, causing internal material leakage and production stoppage losses.

[0006] The combined effect of the above factors results in a short service life for heat exchangers, requiring production to be interrupted for maintenance after as little as one month and as long as six months. Utility Model Content

[0007] To address the shortcomings of existing technologies, this invention provides a heat exchanger for tetrachlorosilane vaporization, thereby solving the problem of short service life caused by easy wear and corrosion of existing heat exchangers.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A heat exchanger for the vaporization of tetrachlorosilane includes:

[0010] The upper end cap, upper tube sheet, intermediate tube, lower tube sheet, and lower end cap are sequentially bolted and sealed together; and

[0011] Several heat exchange tubes are arranged in a ring at equal intervals inside the intermediate cylinder. Each heat exchange tube is connected at both ends to the upper tube sheet and the lower tube sheet, and is also connected to the upper end cap and the lower end cap, respectively.

[0012] The intermediate cylinder has a shell-side inlet in the radial direction and a shell-side outlet located below the shell-side inlet; the upper head cylinder has a tube-side outlet in the radial direction; and the lower head cylinder has a tube-side inlet in the axial direction. An anti-impact plate is tightly fitted to the side of the lower tube sheet facing the lower head cylinder.

[0013] In one embodiment disclosed in this application, the lower end of the upper end cap cylinder is provided with a first flange, the upper and lower ends of the intermediate cylinder are respectively provided with a second flange and a third flange, and the upper end of the lower end cap cylinder is provided with a fourth flange.

[0014] The upper tube sheet is bolted and sealed between the first flange and the second flange. The lower tube sheet is tightly fitted with the anti-impact plate and then bolted and sealed between the third flange and the fourth flange. The anti-impact plate has holes of the same number and corresponding to the lower tube sheet.

[0015] In one embodiment disclosed in this application, the lower tube sheet is made of carbon steel;

[0016] The impact shield is made of silicon carbide.

[0017] In one embodiment disclosed in this application, the upper end of each heat exchange tube is connected to the upper tube sheet by a "strength welding + expansion" method, and the lower end is inserted into the lower tube sheet and threadedly connected to the locking sleeve that passes through the anti-impact plate.

[0018] In one embodiment disclosed in this application, a countersunk hole is provided on the lower tube sheet. The smaller end of the countersunk hole faces the intermediate cylinder, and its inner diameter is equal to the outer diameter of the heat exchange tube. The larger end of the countersunk hole faces the lower end cap cylinder, and its inner diameter is equal to the diameter of the hole on the anti-impact plate.

[0019] The lower end of the heat exchange tube is machined with external threads, which pass through the small hole of the countersunk hole and then extend into the large hole of the countersunk hole.

[0020] The outer diameter of the locking sleeve is equal to the inner diameter of the large hole of the countersunk hole, and its interior is divided into a screw hole section and a through hole section.

[0021] When the locking sleeve passes through the hole in the anti-impact plate, the threaded section is threaded to the lower end of the heat exchange tube;

[0022] A sealing ring is provided between the outer end face of the screw hole section and the interface between the large and small holes of the countersunk hole, and the sealing ring is sleeved on the outside of the heat exchange tube;

[0023] The inner diameter of the through-hole section is equal to the inner diameter of the heat exchange tube, and the outer end face is flush with the side of the anti-impact plate facing the lower end cap cylinder.

[0024] In one embodiment disclosed in this application, a predetermined space is left between the interface between the screw hole section and the through hole section and the lower end of the heat exchange tube, so as to facilitate the adjustment of the tightening degree of the locking sleeve later.

[0025] In one embodiment disclosed in this application, the predetermined space is lined with an elastic protective sleeve;

[0026] The inner diameter of the elastic protective sleeve is equal to the inner diameter of the heat exchange tube.

[0027] In one embodiment disclosed in this application, a pair of disassembly holes spaced 180° apart are provided on the outer end face of the through hole section.

[0028] In one embodiment disclosed in this application, the heat exchange tube is made of silicon carbide;

[0029] The locking sleeve is made of modified polytetrafluoroethylene.

[0030] In one embodiment disclosed in this application, the upper end cap cylinder is provided with a tube side vent in the axial direction. The tube side vent is normally closed and is only opened during tube side pressurization and replacement.

[0031] The intermediate cylinder is radially provided with a shell-side vent and a drain port located below the shell-side vent. The shell-side vent is arranged at a 180° interval from the shell-side inlet and the former is higher than the latter. The drain port is arranged at a 180° interval from the shell-side outlet and the former is lower than the latter.

[0032] The shell-side vent is normally closed and is only opened during shell-side pressurization and replacement processes. The drain port is normally closed and is only opened during maintenance to drain the shell-side medium.

[0033] Compared with the prior art, the beneficial effects of this utility model are:

[0034] 1. Compared with traditional welding methods, the upper and lower tube sheets of this heat exchanger are connected and fixed by bolts, which is conducive to maintenance and replacement. In addition, an anti-impact plate is attached to the material-facing side of the lower tube sheet, which can isolate and protect the lower tube sheet, thereby avoiding direct scouring and corrosion of the tube-side medium on the lower tube sheet. This indirectly ensures the wear resistance and corrosion resistance of the lower tube sheet and effectively extends its service life.

[0035] 2. The lower end of the heat exchange tube is connected to the lower tube sheet by a locking sleeve through a threaded connection, and a sealing ring is used to assist in the sealing. At the same time, the locking sleeve is built into the countersunk hole and does not protrude outward, which can prevent the tube-side medium from scouring and abrading the lower end of the heat exchange tube and avoid perforation, effectively extending the service life of the heat exchange tube. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the structure of this utility model;

[0038] Figure 2 for Figure 1 A magnified schematic diagram of section A in the middle;

[0039] Figure 3 A three-dimensional structural diagram of the locking sleeve;

[0040] Figure 4 This is a cross-sectional view of the locking sleeve. Detailed Implementation

[0041] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this invention. Therefore, the drawings and description are considered exemplary in nature and not restrictive.

[0042] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0044] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0045] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0046] The following disclosure provides many different embodiments or examples for implementing various structures of this invention. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this invention.

[0047] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0048] See Figures 1-4 As shown, this utility model provides a heat exchanger for the vaporization of tetrachlorosilane, comprising:

[0049] The upper end cap 10, upper tube sheet 20, intermediate tube 30, lower tube sheet 40, and lower end cap 50 are sequentially bolted and sealed together; and

[0050] Several heat exchange tubes 60 are arranged in a ring array in the middle cylinder 30 at equal intervals. Each heat exchange tube 60 is connected at both ends to the upper tube sheet 20 and the lower tube sheet 40, and is also connected to the upper end cylinder 10 and the lower end cylinder 50, respectively.

[0051] The intermediate cylinder 30 has a shell-side inlet 31 in the radial direction and a shell-side outlet 32 ​​located below the shell-side inlet 31. The upper end cylinder 10 has a tube-side outlet 11 in the radial direction and the lower end cylinder 50 has a tube-side inlet 51 in the axial direction. The lower tube sheet 40 has an anti-impact plate 70 tightly attached to the side facing the lower end cylinder 50.

[0052] Specifically, the upper end cap 10 is provided with a first flange 12 at its lower end, the intermediate cylinder 30 is provided with a second flange 33 and a third flange 34 at its upper and lower ends respectively, and the lower end cap 50 is provided with a fourth flange 52 at its upper end. The upper tube sheet 20 is bolted and sealed between the first flange 12 and the second flange 33. The lower tube sheet 40 is tightly fitted with the anti-impact plate 70 and bolted and sealed between the third flange 34 and the fourth flange 52. The anti-impact plate 70 has the same number of holes as the lower tube sheet 40, and they correspond one-to-one. During operation, the tetrachlorosilane to be vaporized enters the heat exchange tube 60 from the tube-side inlet 51 through the lower end cap 50. It exchanges heat with the steam entering the intermediate cylinder 30 from the shell-side inlet 31, and is heated and vaporized. It is then discharged from the tube-side outlet 11 through the upper end cap 10, while the steam cools down and becomes condensate, which is discharged from the shell-side outlet 32.

[0053] Compared with traditional welding methods, the upper and lower tube sheets of this heat exchanger are connected and fixed by bolts, which is conducive to maintenance and replacement. In addition, an anti-impact plate 70 is attached to the feed side of the lower tube sheet 40, which can isolate and protect the lower tube sheet 40, thereby avoiding direct scouring and corrosion of the lower tube sheet 40 by the tube-side medium. This indirectly ensures the wear resistance and corrosion resistance of the lower tube sheet 40, effectively extending the service life of the lower tube sheet 40.

[0054] In this embodiment, the material of the lower tube sheet 40 is preferably carbon steel, and the material of the anti-impact plate 70 is preferably silicon carbide.

[0055] Each heat exchange tube 60 is connected to the upper tube sheet 20 at the upper end using a "strength welding + expansion" method (i.e., the same connection method as existing heat exchangers), and its lower end is inserted into the lower tube sheet 40 and threadedly connected to the locking sleeve 80 that passes through the anti-impact plate 70. The side of the upper tube sheet 20 facing the upper head cylinder 10 is the discharge side, so the upper end of the heat exchange tube 60 is still connected to the upper tube sheet 20 using the "strength welding + expansion" method, and its tube head protruding from this side will not be eroded or worn by the tube-side medium; while the lower end of the heat exchange tube 60 is on the receiving side, so the tube head at this end is recessed and placed inside the lower tube sheet 40, and then locked by the locking sleeve 80. Specifically, a countersunk hole 41 is provided on the lower tube sheet 40. The smaller end of the countersunk hole 41 faces the intermediate cylinder 30, and its inner diameter is equal to the outer diameter of the heat exchange tube 60. The larger end of the countersunk hole 41 faces the lower end cap cylinder 50, and its inner diameter is equal to the diameter of the hole on the anti-impact plate 70. The lower end of the heat exchange tube 60 is machined with external threads, which pass through the smaller hole of the countersunk hole 41 and extend into the larger hole of the countersunk hole 41. The outer diameter of the locking sleeve 80 is equal to the inner diameter of the larger hole of the countersunk hole 41. The tube sheet consists of a threaded section 81 and a through-hole section 82. When the locking sleeve 80 passes through the hole in the anti-impact plate 70, the threaded section 81 is threadedly connected to the lower end of the heat exchange tube 60. A sealing ring 61 is provided between the outer end face of the threaded section 81 and the interface between the large and small holes of the countersunk hole 41, and the sealing ring 61 is fitted on the outside of the heat exchange tube 60. The inner diameter of the through-hole section 82 is equal to the inner diameter of the heat exchange tube 60, and the outer end face is flush with the side of the anti-impact plate 70 facing the lower end cap 50. That is to say, the lower end of the heat exchange tube 60 is connected to the lower tube sheet 40 by the locking sleeve 80 through a threaded connection, and the sealing ring 61 is used to assist in the sealing. At the same time, the locking sleeve 80 is built into the countersunk hole 41 and does not protrude outward, which can prevent the tube-side medium from scouring and abrading the lower end of the heat exchange tube 60 and avoid perforation, effectively extending the service life of the heat exchange tube 60.

[0056] A predetermined space is left between the interface between the screw hole section 81 and the through hole section 82 and the lower end of the heat exchange tube 60 to facilitate subsequent adjustment of the tightening degree of the locking sleeve 80. By adjusting the tightening degree of the locking sleeve 80, the axial length of this predetermined space can be changed, thereby adjusting the clamping force of the sealing ring 61 and realizing the adjustment of the sealing performance of the sealing ring 61.

[0057] The predetermined space is lined with an elastic protective sleeve 62, the inner diameter of which is equal to the inner diameter of the heat exchange tube 60. The elastic protective sleeve 62 protects the internal threads of the threaded section 81 from being eroded and worn by the tube-side medium.

[0058] To facilitate the rotation of the locking sleeve 80 within the countersunk hole 41, a pair of disassembly holes 83 spaced 180° apart are provided on the outer end face of the through hole section 82. When it is necessary to rotate the locking sleeve 80, a wrench with a pair of pins (not shown in the figure) can be inserted into the disassembly holes 83.

[0059] In this embodiment, the heat exchange tube 60 is preferably made of silicon carbide, which is resistant to erosion and wear, resistant to media corrosion, and has a high thermal conductivity, resulting in better heat transfer performance; the locking sleeve 80 is preferably made of modified polytetrafluoroethylene, such as silicon carbide as the filler, which has better wear resistance; the sealing ring 61 and the protective sleeve 62 are preferably made of high molecular polymers, such as polyvinyl chloride.

[0060] The upper end cap 10 is provided with a tube-side vent 13 in the axial direction. The tube-side vent 13 is normally closed and is only opened during tube-side pressurization and replacement. The intermediate cylinder 30 is provided with a shell-side vent 35 and a drain port 36 located below the shell-side vent 35 in the radial direction. The shell-side vent 35 is arranged at a 180° interval from the shell-side inlet 31 and the former is higher than the latter. The drain port 36 is arranged at a 180° interval from the shell-side outlet 32 ​​and the former is lower than the latter. The shell-side vent 35 is normally closed and is only opened during shell-side pressurization and replacement. The drain port 36 is normally closed and is only opened during maintenance to drain the shell-side medium.

[0061] The above embodiments are merely preferred embodiments of this utility model and are not intended to limit the technical solutions of this utility model. Any technical solution that can be implemented based on the above embodiments without creative effort should be considered to fall within the scope of protection of this utility model patent.

Claims

1. A heat exchanger for the vaporization of tetrachlorosilane, characterized in that, include: The upper end cap, upper tube sheet, intermediate tube, lower tube sheet, and lower end cap are bolted together in sequence and sealed. and Several heat exchange tubes are arranged in a ring at equal intervals inside the intermediate cylinder. Each heat exchange tube is connected at both ends to the upper tube sheet and the lower tube sheet, and is also connected to the upper end cap and the lower end cap, respectively. The intermediate cylinder has a shell-side inlet in the radial direction and a shell-side outlet located below the shell-side inlet; the upper head cylinder has a tube-side outlet in the radial direction; and the lower head cylinder has a tube-side inlet in the axial direction. An anti-impact plate is tightly fitted to the side of the lower tube sheet facing the lower head cylinder.

2. The heat exchanger for tetrachlorosilane vaporization according to claim 1, characterized in that: The upper end cap cylinder is provided with a first flange at its lower end, the middle cylinder is provided with a second flange and a third flange at its upper and lower ends respectively, and the lower end cap cylinder is provided with a fourth flange at its upper end. The upper tube sheet is bolted and sealed between the first flange and the second flange. The lower tube sheet is tightly fitted with the anti-impact plate and then bolted and sealed between the third flange and the fourth flange. The anti-impact plate has holes of the same number and corresponding to the lower tube sheet.

3. The heat exchanger for tetrachlorosilane vaporization according to claim 2, characterized in that: The lower tube sheet is made of carbon steel; The impact shield is made of silicon carbide.

4. The heat exchanger for tetrachlorosilane vaporization according to any one of claims 1 to 3, characterized in that, The upper end of each heat exchange tube is connected to the upper tube sheet by a "strength welding + expansion" method, and the lower end is inserted into the lower tube sheet and threadedly connected to the locking sleeve that passes through the anti-impact plate.

5. The heat exchanger for tetrachlorosilane vaporization according to claim 4, characterized in that: The lower tube sheet has a countersunk hole. The smaller end of the countersunk hole faces the intermediate cylinder, and its inner diameter is equal to the outer diameter of the heat exchange tube. The larger end of the countersunk hole faces the lower end cap cylinder, and its inner diameter is equal to the diameter of the hole on the anti-impact plate. The lower end of the heat exchange tube is machined with external threads, which pass through the small hole of the countersunk hole and then extend into the large hole of the countersunk hole. The outer diameter of the locking sleeve is equal to the inner diameter of the large hole of the countersunk hole, and its interior is divided into a screw hole section and a through hole section. When the locking sleeve passes through the hole in the anti-impact plate, the threaded section is threaded to the lower end of the heat exchange tube; A sealing ring is provided between the outer end face of the screw hole section and the interface between the large and small holes of the countersunk hole, and the sealing ring is sleeved on the outside of the heat exchange tube; The inner diameter of the through-hole section is equal to the inner diameter of the heat exchange tube, and the outer end face is flush with the side of the anti-impact plate facing the lower end cap cylinder.

6. The heat exchanger for tetrachlorosilane vaporization according to claim 5, characterized in that, A predetermined space is left between the interface between the screw hole section and the through hole section and the lower end of the heat exchange tube to facilitate subsequent adjustment of the tightening degree of the locking sleeve.

7. The heat exchanger for tetrachlorosilane vaporization according to claim 6, characterized in that: The predetermined space is lined with an elastic protective sleeve; The inner diameter of the elastic protective sleeve is equal to the inner diameter of the heat exchange tube.

8. The heat exchanger for tetrachlorosilane vaporization according to any one of claims 5 to 7, characterized in that, The outer end face of the through hole section is provided with a pair of disassembly and assembly holes spaced 180° apart.

9. The heat exchanger for tetrachlorosilane vaporization according to claim 8, characterized in that: The heat exchange tube is made of silicon carbide; The locking sleeve is made of modified polytetrafluoroethylene.

10. The heat exchanger for tetrachlorosilane vaporization according to claim 1 or 9, characterized in that: The upper end cap cylinder is provided with a tube side vent in the axial direction. The tube side vent is normally closed and is only opened during tube side pressurization and replacement. The intermediate cylinder is radially provided with a shell-side vent and a drain port located below the shell-side vent. The shell-side vent is arranged at a 180° interval from the shell-side inlet and the former is higher than the latter. The drain port is arranged at a 180° interval from the shell-side outlet and the former is lower than the latter. The shell-side vent is normally closed and is only opened during shell-side pressurization and replacement processes. The drain port is normally closed and is only opened during maintenance to drain the shell-side medium.

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