A perfluorinated shell-and-tube heat exchanger for secondary cooling of hydrofluoric acid

Abstract

This utility model discloses a perfluorinated shell-and-tube heat exchanger for secondary cooling of hydrofluoric acid, belonging to the technical field of heat exchanger equipment. It includes a shell, with heat exchange tubes arranged inside the shell cavity. Cooling water inlets and outlets are located at the ends of the shell and are sealed to the heat exchange tubes for cooling water to enter and exit. The shell is equipped with an acid vapor inlet, an acid liquid outlet, and a tail gas outlet, all communicating with its inner cavity. The heat exchange tubes are made of fluoroplastic, and the shell is made of metal with an inner fluoroplastic lining. Cooling water is introduced into the heat exchange tubes, while the acid vapor condenses by exchanging heat with the cooling water inside the heat exchange tubes within the shell cavity and outside the tubes. The shell has an acid liquid outlet and a tail gas outlet, which can collect liquid acid, uncondensed acid vapor, and other impurity gases, respectively. The fluoroplastic lining of the shell and the use of fluoroplastic in the heat exchange tubes effectively resist acid corrosion, and the metal shell has higher strength. Furthermore, the sealing structure of each part of the shell has high strength and is not easily deformed or damaged.

Description

Technical Field

[0001] This utility model belongs to the technical field of heat exchanger equipment, specifically to a hydrofluoric acid secondary cooling perfluorinated shell-and-tube heat exchanger. Background Technology

[0002] Hydrofluoric acid is an aqueous solution of hydrogen fluoride gas. It is a clear, colorless, fuming, corrosive liquid with a strong, pungent odor. Hydrofluoric acid is a weak acid with extremely high corrosiveness, capable of severely corroding metals, glass, and silicon-containing materials.

[0003] Chinese Patent Publication No. CN215667147U discloses a saturated hydrofluoric acid production system. A secondary cooler is set between the absorption cooler and the intermediate tank to guide hydrogen fluoride gas to the intermediate tank. By setting up a secondary cooler to cool and guide the supersaturated hydrofluoric acid, the solubility of the supersaturated hydrofluoric acid is higher, which is beneficial to improving the purity of hydrogen fluoride and has strong practicality.

[0004] However, hydrogen fluoride condenses into a liquid state inside the heat exchanger after cooling. Therefore, the heat exchanger needs to collect liquid hydrogen fluoride, as well as uncondensed hydrogen fluoride and other impurity gases, and be able to resist corrosion from hydrogen fluoride and hydrofluoric acid. At the same time, the condensation of gas due to temperature reduction will lead to negative pressure, so the heat exchanger needs to have sufficient strength and sealing. Existing heat exchangers are difficult to meet the above conditions and are not well suited for secondary cooling of hydrogen fluoride. Utility Model Content

[0005] In view of this, the purpose of this utility model is to overcome the shortcomings of the prior art and provide a perfluorinated shell-and-tube heat exchanger for secondary cooling of hydrofluoric acid. This application provides the following technical solution:

[0006] The device includes a shell, an internal cavity of which is provided with a heat exchange tube, and a cooling water inlet and outlet at the end of the shell. The cooling water inlet and outlet are sealed and connected to the heat exchange tube for cooling water to enter and exit the heat exchange tube. The shell is provided with an acid vapor inlet, an acid liquid outlet, and a tail gas outlet that are connected to its internal cavity. The heat exchange tube is made of fluoroplastic material, and the shell is made of metal material with an inner lining of fluoroplastic.

[0007] The acid vapor inlet and the exhaust gas outlet are located at the upper two ends of the shell, respectively, and the acid liquid outlet is located at the lower part of one end of the exhaust gas outlet.

[0008] The inner cavity of the shell is also provided with several baffles, which are arranged alternately in the upper and lower parts, and the heat exchange tubes pass through the baffles in sequence; the baffles are made of fluoroplastic material.

[0009] The baffle plate is fixedly connected to the end of the housing by a support rod, and a liquid flow channel is left between the bottom of the baffle plate located at the bottom and the inner wall of the housing.

[0010] The end of the housing is provided with an end seat, a tube sheet, and a head in sequence from the inside to the outside. The end seat is sealed to the end of the housing through a loose flange. The tube sheet and the head are both bolted to the studs provided on the end seat.

[0011] A fluororubber sealing gasket is provided between the tube sheet and the end seat, and a fluoroplastic sealing gasket is provided between the end cap and the tube sheet.

[0012] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0013] Cooling water is introduced into the heat exchange tubes, while acid vapors exchange heat with the cooling water inside the heat exchange tubes and in the shell cavity to achieve condensation. The shell is equipped with an acid outlet and a tail gas outlet, which can collect liquid acid, uncondensed acid vapors and other impurity gases respectively. The shell is lined with a fluoroplastic layer, and the heat exchange tubes are made of fluoroplastic material, which can effectively resist acid corrosion. When the acid vapors exchange heat in the shell cavity and generate negative pressure, the metal shell has higher strength, and the sealing structure of each part of the shell also has high strength, making it less prone to deformation or damage.

[0014] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of a perfluorinated shell-and-tube heat exchanger with secondary cooling for hydrofluoric acid.

[0017] Figure 2 This is a cross-sectional view of the end of a perfluorinated shell-and-tube heat exchanger with secondary hydrofluoric acid cooling.

[0018] Figure 3 This is an enlarged view of the baffle plate of a perfluorinated shell-and-tube heat exchanger with secondary cooling for hydrofluoric acid.

[0019] Figure 4 This is a schematic diagram of a baffle plate in a perfluorinated shell-and-tube heat exchanger with secondary cooling for hydrofluoric acid.

[0020] Reference numerals: 1. Shell; 11. End seat; 111. Stud; 12. Loose flange; 2. Heat exchange tube; 21. Tube sheet; 22. Fluororubber gasket; 3. Cooling water inlet / outlet; 31. End cap; 32. Fluoroplastic gasket; 4. Acid vapor inlet; 5. Acid liquid outlet; 6. Exhaust gas outlet; 7. Baffle plate; 71. Liquid flow channel; 8. Support rod. Detailed Implementation

[0021] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0022] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," 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 mechanical connection or an electrical connection; 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. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0023] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0024] Please refer to Figure 1-4 As shown, this utility model provides a perfluorinated shell-and-tube heat exchanger for secondary cooling of hydrofluoric acid, including a shell 1, a heat exchange tube 2 disposed in the inner cavity of the shell 1, a cooling water inlet / outlet 3 disposed at the end of the shell 1, the cooling water inlet / outlet 3 being sealed and connected to the heat exchange tube 2 for cooling water to enter and exit the heat exchange tube 2, and an acid vapor inlet 4, an acid liquid outlet 5, and a tail gas outlet 6 disposed on the shell 1 and connected to its inner cavity; wherein, the heat exchange tube 2 is made of fluoroplastic material, the shell 1 is made of metal material, and is lined with a layer of fluoroplastic.

[0025] The acid gas inlet 4 and the exhaust gas outlet 6 are located at the upper two ends of the shell 1, respectively, and the acid liquid outlet 5 is located at the lower part of one end of the exhaust gas outlet 6.

[0026] Several baffles 7 are also provided in the inner cavity of the shell 1. The baffles 7 are arranged alternately, and the heat exchange tubes 2 pass through the baffles 7 in sequence. The baffles 7 are made of fluoroplastic material.

[0027] The baffle plate 7 is fixedly connected to the end of the housing 1 by the support rod 8, and a liquid flow channel 71 is left between the bottom of the baffle plate 7 located at the bottom and the inner wall of the housing 1.

[0028] Specifically, such as Figure 3 As shown, the liquid flow channel 71 is a pre-reserved gap between the bottom of the baffle 7 and the inner wall of the housing 1, as... Figure 4 As shown, it can also be a channel formed by a through hole opened at the bottom of the baffle 71.

[0029] like Figure 2 As shown, from the inside to the outside, the end of the housing 1 is provided with an end seat 11, a tube sheet 21 and a head 31. The end seat 11 is sealed to the end of the housing 1 through a loose flange 12. The tube sheet 21 and the head 31 are both bolted to the studs 111 provided on the end seat 11.

[0030] A fluororubber gasket 22 is provided between the tube sheet 21 and the end seat 11, and a fluoroplastic gasket 32 ​​is provided between the end cap 31 and the tube sheet 21.

[0031] Specifically, the shell 1, acid vapor inlet 4, acid liquid outlet 5, and exhaust gas outlet 6 are made of 305 stainless steel in one piece or by welding, and the inner wall is molded with a layer of PTFE plastic; the end cap 31 and the cooling water inlet / outlet 3 are also made of 305 stainless steel in one piece or by welding, and the inside is molded with a layer of PTFE plastic; the end seat 11, support rod 8, and baffle 7 are made of PTFE plastic, the heat exchange tube 2 and tube sheet 21 are made of PFA plastic, the heat exchange tube 2 is welded and fixed to the tube sheet 21, the support rod 8 is integrally formed or welded and fixed to the end seat 11, the baffle 7 is welded to the support rod 8 or snapped into the groove set on the support rod 8, and the baffle 7 has several through holes pre-made on it, through which the heat exchange tube 2 passes; the stud 111, the loose flange 12, and the nuts used in each part are all made of 305 stainless steel, and one end of the stud 111 is embedded in the end seat 11.

[0032] Furthermore, the diameter of the acid vapor inlet 4 should be larger than the diameter of the acid liquid outlet 5 and the exhaust gas outlet 6. Taking the shell 1 with a diameter of DN350 and a length of 3500mm as an example, it is recommended that the diameter of the acid vapor inlet 4 be DN300 and the diameters of the acid liquid outlet 5 and the exhaust gas outlet 6 be DN50.

[0033] In specific implementation, the cooling water inlet / outlet 3 is connected to the cooling water supply equipment or heat dissipation equipment to form a liquid flow circulation. The cooling water enters the end cap 31 through the cooling water inlet / outlet 3, and from the end cap 31, it passes through the tube sheet 21 and enters each heat exchange tube 2. After passing through the heat exchange tube 2, it flows to the tube sheet 21 on the other side and flows out from the cooling water outlet 3 on the other end cap 31. The acid vapor enters the inner cavity of the shell 1 from the acid vapor inlet 4, and flows through the bend path formed by the baffle 7 to the acid liquid outlet 5 and the tail gas outlet 6. During the flow, the acid vapor exchanges heat with the cooling water in the heat exchange tube 2. The condensed liquid acid flows to the bottom of the inner cavity of the shell 1 by gravity, flows through the liquid flow channel 71 to the acid liquid outlet 5, and flows out from the acid liquid outlet 5. The remaining gas is output from the tail gas outlet 6.

[0034] Furthermore, in the saturated hydrofluoric acid production system, the acid vapor inlet 4 is connected to the collection and cooler, and the tail gas outlet 6 and the acid liquid outlet 5 are both connected to the intermediate tank, so that both the acid liquid and the gas are introduced into the intermediate tank. After multiple cycles of the system, the gas in the intermediate tank is collected by the tail gas collection device. One-way valves are installed between the acid vapor inlet 4 and the collection and cooler, as well as between the tail gas outlet 6 and the acid liquid outlet 5 and the intermediate tank, to ensure the flow of materials.

[0035] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A hydrogen fluoride acid secondary cooling all-fluorine shell-and-tube heat exchanger, comprising a shell (1), a heat exchange tube (2) is arranged in the inner cavity of the shell (1), characterized in that: The end of the shell (1) is provided with a cooling water inlet and outlet (3), which is sealed and connected to the heat exchange tube (2) for cooling water to enter and exit the heat exchange tube (2). The shell (1) is provided with an acid vapor inlet (4), an acid liquid outlet (5) and a tail gas outlet (6) connected to its inner cavity. The heat exchange tube (2) is made of fluoroplastic material, and the shell (1) is made of metal material with a layer of fluoroplastic lining.

2. A hydrofluoric acid secondary cooling all-fluoropolymer shell-and-tube heat exchanger according to claim 1, characterized in that: The acid vapor inlet (4) and the tail gas outlet (6) are located at the upper two ends of the shell (1), and the acid liquid outlet (5) is located at the lower part of one end of the tail gas outlet (6).

3. A hydrofluoric acid secondary cooling all-fluoropolymer shell-and-tube heat exchanger according to claim 1, characterized in that: The inner cavity of the shell (1) is also provided with several baffles (7), which are arranged alternately up and down, and the heat exchange tube (2) passes through the baffles (7) in sequence; the baffles (7) are made of fluoroplastic material.

4. A hydrofluoric acid secondary cooling all-fluoropolymer shell-and-tube heat exchanger according to claim 3, characterized in that: The baffle plate (7) is fixedly connected to the end of the housing (1) by a support rod (8), and a liquid flow channel (71) is left between the bottom of the baffle plate (7) located below and the inner wall of the housing (1).

5. A hydrofluoric acid secondary cooling all-fluoropolymer shell-and-tube heat exchanger as set forth in claim 1, characterized in that: The end of the housing (1) is provided with an end seat (11), a tube sheet (21) and a head (31) in sequence from the inside to the outside. The end seat (11) is sealed to the end of the housing (1) through a loose flange (12). The tube sheet (21) and the head (31) are both bolted to the studs (111) provided on the end seat (11).

6. A hydrofluoric acid secondary cooling all-fluoropolymer shell-and-tube heat exchanger as set forth in claim 5, characterized in that: A fluororubber gasket (22) is provided between the tube sheet (21) and the end seat (11), and a fluoroplastic gasket (32) is provided between the end cap (31) and the tube sheet (21).

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