Heat exchanger for electronic grade sulfuric acid production

Abstract

The utility model provides a heat exchanger for electronic-grade sulfuric acid production, which relates to the field of electronic-grade sulfuric acid treatment and comprises a shell and a heat exchange tube, the heat exchange tube is made of polytetrafluoroethylene materials, a partition plate fixed on the inner wall of the shell is arranged inside the shell, the partition plate divides the inside of the shell into two heat exchange chambers from top to bottom, and the two heat exchange chambers are communicated end to end. The heat exchange chambers are respectively a first heat exchange chamber and a second heat exchange chamber from top to bottom, the tail end of the first heat exchange chamber is communicated with the head end of the second heat exchange chamber, the shell is provided with an acid outlet, an acid inlet, a water inlet and a water outlet, the top end of the shell is provided with the water inlet, and the water inlet is located at the head end of the first heat exchange chamber and is adjacent to the acid outlet or the acid inlet; the water outlet and the acid inlet or the acid outlet are located on the same side and located at the tail end of the second heat exchange chamber; the heat exchange tube sequentially penetrates into the second heat exchange chamber through the flange at the acid inlet from the outside of the shell, then is bent to penetrate into the first heat exchange chamber, and penetrates out of the outside of the shell from the flange at the acid outlet; the device has the beneficial effects that the quality of electronic-grade sulfuric acid is guaranteed, and the heat exchange effect is good.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of electronic grade sulfuric acid processing, especially relates to a heat exchanger for electronic grade sulfuric acid production. BACKGROUND

[0002] The current electronic grade sulfuric acid production process of the company includes a heat exchange cooling step, and a plate heat exchanger is used in the heat exchange cooling step in actual production, and the heat exchanger is made of Hastelloy material. Since the Hastelloy has a high nickel content, a small amount of nickel ions will enter the electronic grade sulfuric acid during the heat exchange process, resulting in a high nickel content in the electronic grade sulfuric acid product, and the quality of the electronic grade sulfuric acid cannot meet the requirements.

[0003] The company previously developed a sulfuric acid cooler for use in an electronic grade sulfuric acid production system, with publication number CN212902770U. The cooler shell is provided with a polytetrafluoroethylene layer, and the heat exchange pipes for containing acid are also made of polytetrafluoroethylene material, thus reducing the problem of metal impurities being brought in. However, it was found during use that the polytetrafluoroethylene material does not have as good a heat conductivity as metal materials. In combination with the current arrangement of water inlets and outlets on the right and left sides of the shell, cold water continuously enters from the right side, mixes with hot water that has been used for heat exchange, and is then used for heat exchange in the heat exchange pipes. There is no clear water flow channel in the shell, so the water temperature in the shell is high. Ultimately, the heat exchange effect of the acid is poor. Therefore, we have redeveloped a heat exchanger for electronic grade sulfuric acid production. SUMMARY

[0004] To solve the above problems, the utility model provides a heat exchanger for electronic grade sulfuric acid production which guarantees the quality of electronic grade sulfuric acid and has good heat exchange effect.

[0005] The technical scheme of the utility model is as follows:

[0006] The application discloses a heat exchanger for producing electronic-grade sulfuric acid, which comprises a shell and a plurality of heat exchange pipes for containing acid in the shell, wherein the heat exchange pipes are made of polytetrafluoroethylene material, a partition plate is arranged in the shell and fixed to the inner wall of the shell, the shell is divided into two heat exchange chambers which are communicated with each other in sequence from top to bottom, the two heat exchange chambers are respectively a first heat exchange chamber and a second heat exchange chamber, the tail end of the first heat exchange chamber is communicated with the head end of the second heat exchange chamber, the shell is provided with an acid outlet, an acid inlet, a water inlet and a water outlet, the water inlet is arranged at the top end of the shell and located at the head end of the first heat exchange chamber and close to the acid outlet or the acid inlet, the water outlet is located at the tail end of the second heat exchange chamber and on the same side of the acid inlet or the acid outlet, and flanges are arranged on the shell at the acid outlet and the acid inlet, the heat exchange pipes are sequentially inserted into the second heat exchange chamber through the flange at the acid inlet from the outside of the shell, then bent and inserted into the first heat exchange chamber, and then taken out from the flange at the acid outlet to the outside of the shell, or the heat exchange pipes are sequentially inserted into the first heat exchange chamber through the flange at the acid inlet from the outside of the shell, then bent and inserted into the second heat exchange chamber, and then taken out from the flange at the acid outlet to the outside of the shell.

[0007] Preferably, the upper and lower sides of the shell are respectively provided with an acid outlet and an acid inlet, the water inlet is arranged close to one side of the shell and close to the acid outlet, and the water outlet arranged on one side of the shell is close to the acid inlet and on the same side of the acid inlet, the acid outlet is located at the head end of the first heat exchange chamber, and the acid inlet and the water inlet are arranged on the shell at the tail end of the second heat exchange chamber.

[0008] Further, a plurality of heat exchange chambers which are communicated with each other in sequence are arranged between the first heat exchange chamber and the second heat exchange chamber.

[0009] Further, the number of the heat exchange pipes is n, and the diameter of the heat exchange pipes is less than or equal to 2 cm.

[0010] The shell is made of metal material, the partition plate is made of metal material, the partition plate is welded to the shell, and a polytetrafluoroethylene layer is arranged on the surface of the partition plate after welding, and a polytetrafluoroethylene layer is arranged in the shell.

[0011] The limiting plate is arranged in the second heat exchange chamber and close to the middle position of the length direction of the second heat exchange chamber, the shape and size of the limiting plate are matched with the inner wall of the second heat exchange chamber, so that the limiting plate is fixed in the second heat exchange chamber, the limiting plate is covered with limiting holes, the heat exchange pipes pass through n limiting holes, and the diameter of the heat exchange pipes is less than the diameter of the limiting holes.

[0012] The limiting plate is made of metal material, and the limiting plate is welded in the second heat exchange chamber and provided with a polytetrafluoroethylene layer on the surface of the limiting plate.

[0013] Further, the height and width of the first heat exchange chamber and the second heat exchange chamber are 2-4 times of the diameter of the flanges on the acid outlet and the acid inlet.

[0014] The length of the first heat exchange chamber and the second heat exchange chamber is more than 15 times of the diameter of the flange on the acid outlet and the acid inlet, and further, the total water containing capacity in the first heat exchange chamber and the second heat exchange chamber is 2-6 times of the acid containing capacity in the n heat exchange tubes in the first heat exchange chamber and the second heat exchange chamber;

[0015] Further, the temperature sensor on the shell at the water outlet and the temperature sensor on the flange at the acid outlet are arranged to measure the temperature of the acid in the heat exchange tube.

[0016] The beneficial effects of the present application are as follows:

[0017] Since the heat exchange tube for containing acid is made of polytetrafluoroethylene material, there is no problem of introducing metal impurities such as nickel ions, which ensures that there is no problem of introducing impurities and ensures the quality of the acid. Although the heat exchange effect of polytetrafluoroethylene material is not as good as that of metal material, we can change the diameter of the heat exchange tube, use a relatively thin heat exchange tube, and increase the length of the heat exchange. Combined with the clear water flow channel, the water flows from the upper water inlet, and the water flows from the water outlet from high to low, and the water flow is much larger than the acid flow. Therefore, the heat exchange effect is good, which meets the heat exchange demand. By using the device, the liquid temperature is reduced by at least 10 degrees or more, and the heat exchange effect is also significantly improved.

[0018] The polytetrafluoroethylene material is relatively soft, the shell, the partition plate and the partition plate are all made of metal material, which has high strength and long service life. By arranging a polytetrafluoroethylene layer on the surface of the shell, the partition plate and the partition plate, it has a corrosion-resistant effect in the case of high salt content in water.

[0019] The water inlet is adjacent to the acid outlet, so the water with the lowest temperature is used for heat exchange of the acid that is about to be completely heat exchanged, which ensures that the temperature of the acid coming out of the shell meets the requirements. The temperature sensor on the shell at the water outlet and the temperature sensor on the flange at the acid outlet are arranged to measure the temperature of the acid in the heat exchange tube, which is used for adjusting the water flow, speed, acid extraction flow and speed in the later stage, and ensuring that the temperature of the acid meets the requirements.

[0020] Since the heat exchange tube is a flexible tube, the heat exchange tube has a certain length and weight, so the heat exchange tube of the second heat exchange chamber will be placed on the bottom surface of the second heat exchange chamber without lifting, which will affect the heat exchange effect. By separating and lifting one by one with the limiting plate, the heat exchange effect is ensured, and the limiting plate is full of limiting holes, so the water flow is not affected.

[0021] Since the height and width of the first heat exchange chamber and the second heat exchange chamber are 2-4 times of the diameter of the flange on the acid outlet and the acid inlet, and the total water containing capacity in the first heat exchange chamber and the second heat exchange chamber is 2-6 times of the acid containing capacity in the n heat exchange tubes in the first heat exchange chamber and the second heat exchange chamber, the water flow is much larger than the acid flow, so the heat exchange effect is good. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 This is a schematic diagram of the heat exchanger for electronic-grade sulfuric acid production according to this utility model;

[0023] Figure 2 This is a schematic diagram of the limiting plate and limiting holes;

[0024] Figure 3 A schematic diagram showing the heat exchange tubes passing through the eight limiting holes.

[0025] Figure 4 This is a schematic diagram of the heat exchanger for electronic-grade sulfuric acid production according to this utility model, which includes three heat exchange chambers.

[0026] Figure 5 This is a schematic diagram of the actual distribution of the heat exchange tubes;

[0027] In the picture:

[0028] 1. Shell 2. Heat exchange tubes 3. Partition plate

[0029] 4. Acid outlet 5. Acid inlet 6. Water inlet

[0030] 7. Water outlet; 8. First heat exchange chamber; 9. Second heat exchange chamber

[0031] 10. Limiting plate 11. Limiting hole Detailed Implementation

[0032] Implementation 1:

[0033] A heat exchanger for electronic-grade sulfuric acid production, such as Figure 1 As shown, it includes a stainless steel shell 1 and 36 heat exchange tubes 2 inside the shell 1 for holding acid. The 36 heat exchange tubes 2 are as follows: Figure 5 As shown, it presents a circular matrix distribution in practice. Figure 2 , Figure 3 This is just a schematic diagram. The shell 1 is 5m long, 1m wide, and 2m high. Figure 1The diagram shows the heat exchange tubes 2 in the case of 36 tubes. The heat exchange tubes 2 are made of polytetrafluoroethylene (PTFE), and each heat exchange tube 2 has a diameter of 1 cm. A metal partition plate 3 is welded inside the shell 1, dividing the shell 1 into two interconnected heat exchange chambers from top to bottom. The heat exchange chambers from top to bottom are the first heat exchange chamber 8 and the second heat exchange chamber 9, that is, the upper part is the first heat exchange chamber 8, and the lower part is the second heat exchange chamber 9. The tail end (right end) of the first heat exchange chamber 8 and the head end (right end) of the second heat exchange chamber 9 are connected. The shell 1 is connected, with an acid outlet 4 at the top and an acid inlet 5 at the bottom on one side. A water inlet 6 is located at the top of the shell 1, and a water outlet 7 is on the same side as the acid inlet 5. The acid outlet 4 is located at the beginning of the first heat exchange chamber 8. The shell 1 at the end of the second heat exchange chamber 9 has an acid inlet 5 and a water inlet 6. The heat exchange tube 2 passes through the flange at the acid inlet 5 from outside the shell 1, enters the second heat exchange chamber 9, bends, and then enters the first heat exchange chamber 8. It exits through the flange at the acid outlet 4 to the outside of the shell 1. The heat exchange tube 2 has a certain degree of bending but is not a particularly flexible tube. Figure 1 The heat exchange tube 2 shown is a schematic diagram under ideal conditions. In actual operation, the heat exchange tube 2 tends to slope downwards in the first heat exchange chamber 8, and the tail end of the heat exchange tube 2 will rest on the partition plate 3. Furthermore, it is not at two right angles, but rather a bend inserted into the second heat exchange chamber 9. Figure 1 As shown, a portion of the heat exchange tube 2 in the second heat exchange chamber 9 rests on the bottom surface inside the shell 1, which is detrimental to the uniform heat exchange of the heat exchange tube 2 and has adverse effects on the shell 1 and the heat exchange tube 2. Therefore, a limiting plate 10 is installed in the second heat exchange chamber 9. That is, the limiting plate 10 is installed in the second heat exchange chamber 9 and is located near the middle of the length direction of the second heat exchange chamber 9. The shape and size of the limiting plate 10 match the inner wall of the second heat exchange chamber 9, thereby fixing the limiting plate 10 in the second heat exchange chamber 9. Figure 2 As shown (illustratively), the limiting plate 10 is covered with limiting holes 11, such as... Figure 3 As shown, the heat exchange tube 2 passes through several limiting holes 11 (black solid round holes), and the diameter of the heat exchange tube 2 is smaller than the diameter of the limiting hole 11; the limiting plate 10 separates and supports the heat exchange tubes 2, thus ensuring the heat exchange effect, and the limiting plate 10 is covered with limiting holes 11, so it does not affect the flow of water.

[0034] In working condition, normal temperature water or cold water is pumped into the water inlet 6, the first heat exchange chamber 8 and the second heat exchange chamber 9 in sequence, and the temperature of the water is determined according to the weather. The water is recycled. In winter, the temperature of the water used for heat exchange is lower than that in summer. After the first heat exchange chamber 8 and the second heat exchange chamber 9 are filled with water, acid is pumped into the heat exchange pipe 2 through the pump and the acid inlet in the lower part. At the same time, normal temperature water or cold water is continuously pumped into the first heat exchange chamber 8 and the second heat exchange chamber 9 to cool the acid in the heat exchange pipe 2. The acid is sequentially pumped out through the acid inlet and the acid outlet 5, and the cooling purpose is achieved through the normal temperature water or cold water.

[0035] In the above process, since the heat exchange pipe 2 used for acid storage is made of polytetrafluoroethylene material, there is no problem of introducing metal impurities such as nickel ions. Although the heat exchange effect of the polytetrafluoroethylene material is not as good as that of the metal material, we can increase the length of heat exchange by replacing the diameter of the heat exchange pipe 2 with a relatively thin heat exchange pipe 2. In combination with the clear water flow channel, the water flows from the upper water inlet 6 to the water outlet 7 from high to low, and the flow rate of the water is much larger than that of the acid. Therefore, the heat exchange effect is good, and the heat exchange demand is met. According to actual detection, the temperature of the acid at 50-80℃ is generally reduced by more than 10 degrees after one cycle of heat exchange in the electronic-grade sulfuric acid production heat exchanger. The actual measured temperature is between 40-72℃. The cooling effect is better in winter, and the temperature can be reduced by more than 20℃. The present application meets the requirements of later production.

[0036] The polytetrafluoroethylene material is relatively soft, and the shell 1, the partition plate 3 and the partition plate 3 are all made of metal material, which has high strength and long service life. By arranging a polytetrafluoroethylene layer on the surface of the shell 1, the partition plate 3 and the partition plate 3, the corrosion resistance effect is achieved in the case of high salt content of water (since the water is recycled).

[0037] In the present embodiment, the water inlet 6 is adjacent to the acid outlet 4, so the water with the lowest temperature is used for heat exchange of the acid which is about to complete heat exchange, and the temperature of the acid discharged from the shell 1 meets the requirements.

[0038] Embodiment 2:

[0039] Based on embodiment 1, a first heat exchange chamber 8 and a second heat exchange chamber 9 are provided between the first heat exchange chamber 8 and the second heat exchange chamber 9, and a heat exchange chamber in communication with the first heat exchange chamber 8 and the second heat exchange chamber 9 is arranged, as shown in Figure 4 The heat exchange length is increased, the speed and flow rate of the water inlet and water outlet are increased, and the cooling effect is better. According to the present embodiment, the temperature can be reduced to at least 25℃ or above in winter.

[0040] Embodiment 3:

[0041] On the basis of the embodiments 1 and 2, the temperature sensor on the shell 1 at the water outlet 7 and the temperature sensor on the flange at the acid outlet 4 are used to measure the temperature of the acid in the heat exchange pipe 2 and the temperature of the water, so that when the water temperature is high, the water inflow and speed are accelerated, and the water pumping flow and speed are also accelerated, thereby ensuring the heat exchange effect.

[0042] Embodiment 4:

[0043] When the temperature requirement is lower, the two heat exchangers for producing electronic-grade sulfuric acid in the embodiments are connected in series, and the cooling effect is better.

[0044] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the drawings, and are only used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. Figure 1

[0045] The above describes one embodiment of the present application in detail, but the content described is only a preferred embodiment of the present application, and cannot be considered as limiting the scope of the present application. Any equivalent changes and improvements made within the scope of the present application should still belong to the patent coverage of the present application.​

Claims

1. A heat exchanger for the production of electronic grade sulfuric acid, characterized in that: The application relates to a shell and a plurality of heat exchange pipes for containing acid in the shell, wherein the heat exchange pipes are made of polytetrafluoroethylene material, a partition plate is arranged in the shell, the partition plate is fixed to the inner wall of the shell, the shell is divided into two heat exchange chambers which are connected at the tail ends and communicate with each other from top to bottom, the two heat exchange chambers are respectively a first heat exchange chamber and a second heat exchange chamber, the tail end of the first heat exchange chamber communicates with the head end of the second heat exchange chamber, the shell is provided with an acid outlet, an acid inlet, a water inlet and a water outlet, the water inlet is arranged at the head end of the first heat exchange chamber and is adjacent to the acid outlet or the acid inlet, the water outlet is arranged on the same side of the acid inlet or the acid outlet and is located at the tail end of the second heat exchange chamber, flanges are arranged on the shell at the acid outlet and the acid inlet, the heat exchange pipes are sequentially arranged from outside the shell, pass through the flanges at the acid inlet, are bent to pass into the first heat exchange chamber from the second heat exchange chamber, pass out of the flanges at the acid outlet to the outside of the shell, or the heat exchange pipes are sequentially arranged from outside the shell, pass through the flanges at the acid inlet, are bent to pass into the second heat exchange chamber from the first heat exchange chamber, and pass out of the flanges at the acid outlet to the outside of the shell.

2. The heat exchanger for producing electronic-grade sulfuric acid according to claim 1, characterized in that: The number of the heat exchange pipes is n, and the diameter of the heat exchange pipes is less than or equal to 2 cm.

3. The heat exchanger for producing electronic-grade sulfuric acid according to claim 2, characterized in that: A limiting plate is arranged in the second heat exchange chamber and is close to the middle position of the length direction of the second heat exchange chamber, the limiting plate is matched with the shape and size of the inner wall of the second heat exchange chamber, and then the limiting plate is fixed in the second heat exchange chamber, the limiting plate is provided with a plurality of limiting holes, the heat exchange pipes pass through n limiting holes, and the diameter of the heat exchange pipes is less than the diameter of the limiting holes.

4. The heat exchanger for producing electronic-grade sulfuric acid according to claim 2 or 3, characterized in that: The shell, the partition plate and the limiting plate are all made of metal, and the partition plate and the limiting plate are welded to the shell. After welding, the shell is provided with a polytetrafluoroethylene layer, and the partition plate and the limiting plate are provided with polytetrafluoroethylene layers.

5. The heat exchanger for producing electronic-grade sulfuric acid according to claim 4, characterized in that: The height and width of the first heat exchange chamber and the second heat exchange chamber are 2-4 times the diameter of the flanges at the acid outlet and the acid inlet.

6. The heat exchanger for producing electronic-grade sulfuric acid according to claim 5, characterized in that: The total water capacity in the first heat exchange chamber and the second heat exchange chamber is 2-6 times the acid capacity in the n heat exchange pipes in the first heat exchange chamber and the second heat exchange chamber.

7. The heat exchanger for producing electronic-grade sulfuric acid according to claim 1 or 2 or 3 or 5 or 6, characterized in that: The upper and lower sides of one side of the shell are respectively provided with an acid outlet and an acid inlet, the water inlet is close to one side of the shell and is adjacent to the acid outlet, the water outlet arranged on one side of the shell is adjacent to the acid inlet, the acid outlet is located at the head end of the first heat exchange chamber, and the shell at the tail end of the second heat exchange chamber is provided with an acid inlet and a water inlet.

8. The heat exchanger for producing electronic-grade sulfuric acid according to claim 7, characterized in that: A temperature sensor is arranged on the shell at the water outlet, and a temperature sensor is arranged on the flange at the acid outlet.

9. The heat exchanger for producing electronic-grade sulfuric acid according to claim 8, characterized in that: A temperature sensor is arranged on the shell at the water outlet, and a temperature sensor is arranged on the flange at the acid outlet.

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