Acid-acid heat exchanger for sulfuric acid low-temperature waste heat recovery device

Abstract

The utility model relates to the technical field of heat exchangers, and discloses an acid-acid heat exchanger for a sulfuric acid low-temperature waste heat recovery device, which comprises a shell, a shell pass and a plurality of heat exchange tubes, the shell pass and the heat exchange tubes are positioned in the shell, and the shell pass is a space between the shell and the heat exchange tubes; a first tube plate and a second tube plate are sequentially arranged close to the two opposite ends in the shell, the shell is sequentially divided into a first shell, a second shell and a third shell through the first tube plate and the second tube plate, the first shell is provided with a concentrated sulfuric acid inlet and a first acid discharging port which are communicated with the heat exchange tube, and the second shell is provided with a second acid discharging port which is communicated with the second acid discharging port. A concentrated sulfuric acid outlet and a second acid emptying port which are communicated with the heat exchange tube are formed in the third shell; a dilute sulfuric acid inlet, a dilute sulfuric acid outlet and a third acid emptying port which are communicated with the shell pass are formed in the second shell; wherein the heat exchange tube is connected with the tube plate through a pressing plate. According to the acid-acid heat exchanger, the corrosion resistance and the sealing performance of the acid-acid heat exchanger are improved by optimizing the material and the sealing design, the manufacturing and maintenance processes are simplified, and the cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of heat exchangers, in particular to an acid-acid heat exchanger used in a sulfuric acid low-temperature waste heat recovery device. Background Art

[0002] In the sulfuric acid low-temperature waste heat recovery system, in order to maintain the system water balance, reduce heat energy waste and increase steam production, the current low-temperature waste heat recovery system adopts the method of adding an acid-acid heat exchanger between the desalted water preheater and the deoxygenated water preheater to increase the acid line. The shell, tube sheet, heat exchange tubes, connecting pipes and flanges of the acid-acid heat exchanger are all made of high-silicon alloy materials and are manufactured by welding. Due to the fluctuations in acid concentration and acid temperature, the application range of high-silicon alloy heat exchange tubes is limited. At the same time, the manufacturing cost of high-silicon alloy heat exchange tubes is high and the production cycle is long. In addition, the welding of high-silicon alloy materials requires the use of special welding materials, which places high demands on welders. In particular, the welding quality of the pipe head has always been a difficult point in the control of acid-acid heat exchangers. Once a leak occurs, the maintenance process is cumbersome and time-consuming. For this reason, it is very necessary to develop an acid-acid heat exchanger with a wider range of applications and easier manufacturing and maintenance. Utility Model Content

[0003] In response to the above-mentioned technical deficiencies, the technical problem to be solved by the present invention is to provide an acid-acid heat exchanger for a low-temperature waste heat recovery device for sulfuric acid, aiming to solve the problems of existing high-silicon alloy heat exchangers being easily damaged under acid concentration and acid temperature fluctuations, high cost, difficult welding and difficult maintenance.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solution: The present invention provides an acid-acid heat exchanger for a low-temperature waste heat recovery device for sulfuric acid, comprising:

[0005] The shell and the shell side and the plurality of heat exchange tubes located therein, the shell side being the space between the shell and the plurality of heat exchange tubes;

[0006] Two tube sheets, a first tube sheet and a second tube sheet, are sequentially provided in the shell near opposite ends thereof, and the shell is divided into a first shell, a second shell and a third shell by the first tube sheet and the second tube sheet. The first shell is provided with a concentrated sulfuric acid inlet and a first acid drain port communicating with the heat exchange tubes, the third shell is provided with a concentrated sulfuric acid outlet and a second acid drain port communicating with the heat exchange tubes, and the second shell is provided with a dilute sulfuric acid inlet, a dilute sulfuric acid outlet and a third acid drain port communicating with the shell side.

[0007] Furthermore, the heat exchange tube is connected to the tube sheet via a pressing plate.

[0008] Furthermore, the outer wall of the pressing plate has threads that match the inner threads of the tube holes on the tube plate, and the interior of the pressing plate has a hollow hole, the inner wall of the hole matches the outer wall of the heat exchange tube.

[0009] Further, the inner wall of the heat exchange tube hole on the tube plate has a tapered sealing groove and an internal thread, the internal thread is closer to the heat exchange tube hole than the tapered sealing groove, a trapezoidal sealing ring is fixed on the heat exchange tube, and the trapezoidal sealing ring is fixed at the bottom of the tapered sealing groove and cooperates with the tapered sealing groove, the pressing plate and the heat exchange tube.

[0010] Further, the end of the pressing plate is a chamfered surface, and the chamfered surface is matched with the tapered sealing groove.

[0011] Further, the trapezoidal sealing ring is fixed on the inner side of the pressing plate close to one end of the tapered sealing groove.

[0012] Further, the trapezoidal sealing ring is fixed on the inner side of the pressing plate close to one end of the tapered sealing groove.

[0013] The beneficial effects of the utility model lie in:

[0014] 1. Corrosion-resistant materials such as high-silicon alloy or stainless steel are used to ensure that the heat exchanger can operate stably in a strong acid environment for a long time. The threaded connection of the pressing plate and the tube plate, combined with the design of the trapezoidal sealing ring and the tapered sealing groove, ensures reliable sealing effect and prevents sulfuric acid leakage.

[0015] 2. The pressing plate connection method reduces the welding requirement, reduces the manufacturing cost and maintenance difficulty, improves the manufacturing efficiency and maintenance convenience, optimizes the material selection and manufacturing process, further reduces the overall cost of the equipment, and improves the economic benefit. DRAWINGS

[0016] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the drawings needed in the embodiment or the prior art description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and those skilled in the art can obtain other drawings according to these drawings without creating creative labor.

[0017] Figure 1 It is a structural schematic view of the acid-acid heat exchanger of the low-temperature waste heat recovery device for sulfuric acid.

[0018] Figure 2 It is a schematic view of the connection of the heat exchange tube and the tube plate.

[0019] Explanation of the reference numerals: 1. Shell side; 2. Heat exchange tube; 3. Tube sheet; 4. Pressure plate; 5. First shell; 6. Second shell; 7. Third shell; 51. Concentrated sulfuric acid inlet; 52. First acid drain port; 61. Dilute sulfuric acid inlet; 62. Dilute sulfuric acid outlet; 63. Second acid drain port; 71. Concentrated sulfuric acid outlet; 72. Third acid drain port; 31. Trapezoidal sealing ring; 32. Conical sealing groove. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] Example 1

[0022] like Figure 1 and Figure 2 As shown, this embodiment relates to an acid-acid heat exchanger for a sulfuric acid low-temperature waste heat recovery device, such as Figure 1 As shown, it includes a shell, a shell side 1, a plurality of heat exchange tubes 2, a first tube sheet 3 and a second tube sheet 3. The shell is made of corrosion-resistant material to adapt to the corrosive environment of sulfuric acid. The shell side 1 is the space between the shell and the plurality of heat exchange tubes 2, which is used to accommodate dilute sulfuric acid. The shell is divided into three parts by the first tube sheet and the second tube sheet: a first shell 5, a second shell 6 and a third shell 7. The first shell 5 is provided with a concentrated sulfuric acid inlet 51 and a first acid drain port 52 communicating with the heat exchange tubes 2. The second shell 6 is provided with a dilute sulfuric acid inlet 61, a dilute sulfuric acid outlet 62 and a second acid drain port 63 communicating with the shell side 1. The third shell 7 is provided with a concentrated sulfuric acid outlet 71 and a third acid drain port 72 communicating with the heat exchange tubes 2. The heat exchange tubes 2 are connected to the tube sheet 3 through a pressing plate 4, as shown in FIG. Figure 2 As shown, the outer wall of the pressure plate 4 has threads that mate with the internal threads of the tube hole on the tube sheet 3. The interior of the pressure plate 4 has a hollow hole, the inner wall of which mates with the outer wall of the heat exchange tube 2. A conical sealing groove 32 and an internal thread are provided on the inner wall of the heat exchange tube 2 hole on the tube sheet 3, wherein the internal thread is closer to the opening of the heat exchange tube 2 than the conical sealing groove 32. A trapezoidal sealing ring 31 is fixed to the inner section of the heat exchange tube 2 located in the heat exchange tube 2 hole. The trapezoidal sealing ring 31 is fixed to the bottom of the conical sealing groove 32 and mates with the conical sealing groove 32, the pressure plate 4, and the heat exchange tube 2 to ensure sealing performance. The end of the pressure plate 4 has a beveled surface that fits the conical sealing groove 32, further enhancing the sealing effect. The trapezoidal sealing ring 31 can be fixed to the inner side of the pressure plate 4 and the conical sealing groove 32 near one end, or it can be bonded to the bottom of the conical sealing groove 32 or to the inner side of the pressure plate 4 and the conical sealing groove 32 near one end.

[0023] Specifically, first, use corrosion-resistant materials such as high-silicon alloy or stainless steel to make the shell to ensure that it can withstand the corrosion of sulfuric acid; then, make the first tube sheet and the second tube sheet, and drill holes on the tube sheet 3, and process internal threads and tapered sealing grooves 32 in the holes; then, pass the heat exchange tube 2 through the first tube sheet and the second tube sheet, ensuring that the heat exchange tube 2 is tightly fitted with the inner wall of the hole; then, screw the pressure plate 4 into the hole on the tube sheet 3, ensuring that the pressure plate 4 is fully engaged with the internal threads of the heat exchange tube 2 hole; fix the trapezoidal sealing ring 31 on the inner section of the heat exchange tube 2 hole The bottom of the conical sealing groove 32 is ensured to be tightly fitted between the sealing ring and the conical sealing groove 32, the pressure plate 4 and the heat exchange tube 2; finally, the first tube sheet 3 and the second tube sheet 3 are installed in the shell, ensuring that the first shell 5, the second shell 6 and the third shell 7 are correctly divided; the concentrated sulfuric acid inlet 51 and the first acid drain port 52 are installed on the first shell 5, the concentrated sulfuric acid outlet 71 and the second acid drain port 63 are installed on the third shell 7, and the dilute sulfuric acid inlet 61, the dilute sulfuric acid outlet 62 and the third acid drain port 72 are installed on the second shell 6.

[0024] Specifically, concentrated sulfuric acid enters the heat exchange tube 2 through the concentrated sulfuric acid inlet 51 on the first shell 5, and dilute sulfuric acid enters the shell side 1 through the dilute sulfuric acid inlet 61 on the second shell 6; the concentrated sulfuric acid flows in the heat exchange tube 2 and exchanges heat with the dilute sulfuric acid in the shell side 1, and the heat of the concentrated sulfuric acid is transferred to the dilute sulfuric acid through the heat exchange tube 2, causing the dilute sulfuric acid to heat up; the concentrated sulfuric acid after heat exchange is discharged through the concentrated sulfuric acid outlet 71 on the third shell 7, and the dilute sulfuric acid after heat exchange is discharged through the dilute sulfuric acid outlet 62 on the second shell 6; in addition, the three acid drain ports of the acid-acid heat exchanger are used to discharge residual acid in the system to ensure cleanliness and safety during system startup and shutdown. In this way, effective recovery of low-temperature waste heat of sulfuric acid is achieved.

[0025] Preferably, the pressing plate 4 cooperates with the internal thread on the tube sheet 3 through the thread on its outer wall. After tightening, the pressing plate 4 generates an axial pressing force on the heat exchange tube 2 to ensure the seal between the heat exchange tube 2 and the tube sheet 3. There is a hollow hole inside the pressing plate 4, and the inner wall of the hole cooperates tightly with the outer wall of the heat exchange tube 2, further enhancing the sealing effect; the trapezoidal sealing ring 31 is fixed at the bottom of the conical sealing groove 32, which can be fixed at the inner side of the pressing plate 4 and the conical sealing groove 32 near one end, or can be bonded to the bottom of the conical sealing groove 32 or the inner side of the pressing plate 4 and the conical sealing groove 32 near one end, and fits tightly with the beveled surface of the pressing plate 4 and the outer wall of the heat exchange tube 2 to form a multiple seal. When the pressing plate 4 is tightened, the trapezoidal sealing ring 31 is compressed, generating a radial sealing force, forming a tight sealing interface with the conical sealing groove 32, the pressing plate 4 and the outer wall of the heat exchange tube 2 to prevent sulfuric acid leakage.

[0026] The above are only preferred embodiments of the present application, and are not used to limit the present application, and although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An acid-acid heat exchanger for a low-temperature waste heat recovery device for sulfuric acid, characterized in that: include: The shell and the shell side and the plurality of heat exchange tubes located therein, the shell side being the space between the shell and the plurality of heat exchange tubes; Two tube sheets, a first tube sheet and a second tube sheet, are sequentially provided in the shell near opposite ends thereof, and the shell is divided into a first shell, a second shell and a third shell by the first tube sheet and the second tube sheet. The first shell is provided with a concentrated sulfuric acid inlet and a first acid drain port communicating with the heat exchange tubes, the third shell is provided with a concentrated sulfuric acid outlet and a second acid drain port communicating with the heat exchange tubes, and the second shell is provided with a dilute sulfuric acid inlet, a dilute sulfuric acid outlet and a third acid drain port communicating with the shell side.

2. The acid-acid heat exchanger for a low-temperature waste heat recovery device for sulfuric acid according to claim 1, characterized in that: The heat exchange tubes are connected to the tube sheet via a pressure plate.

3. The acid-acid heat exchanger for a low-temperature waste heat recovery device for sulfuric acid according to claim 2, characterized in that: The outer wall of the pressing plate has a thread that matches the inner thread of the tube hole on the tube plate. The inside of the pressing plate has a hollow hole, and the inner wall of the hole matches the outer wall of the heat exchange tube.

4. The acid-acid heat exchanger for a low-temperature waste heat recovery device for sulfuric acid according to claim 1, characterized in that: There is a conical sealing groove and an internal thread on the inner wall of the heat exchange tube hole on the tube sheet, wherein the internal thread is closer to the heat exchange tube mouth than the conical sealing groove. A trapezoidal sealing ring is fixed on the heat exchange tube located in the inner section of the heat exchange tube hole. The trapezoidal sealing ring is fixed to the bottom of the conical sealing groove and cooperates with the conical sealing groove, the pressure plate and the heat exchange tube.

5. The acid-acid heat exchanger for a low-temperature waste heat recovery device for sulfuric acid according to claim 4, characterized in that: The end of the pressing plate is a beveled surface that fits the conical sealing groove.

6. The acid-acid heat exchanger for a low-temperature waste heat recovery device for sulfuric acid according to claim 4, characterized in that: The trapezoidal sealing ring is also fixed on the inner side of the pressure plate and the conical sealing groove close to one end.

7. The acid-acid heat exchanger for a low-temperature waste heat recovery device for sulfuric acid according to claim 4, characterized in that: The trapezoidal sealing ring is bonded to the bottom of the conical sealing groove or to the inner side of the pressing plate and the conical sealing groove close to one end.

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