Hydrofluoric acid recovery purifier

Abstract

The utility model belongs to the technical field of hydrofluoric acid recovery and purification, especially a kind of hydrofluoric acid recovery and purification device, including evaporator, for heating treatment to hydrofluoric acid wastewater;Steam collecting pipe, with the steam outlet intercommunication of evaporator;Condensing equipment, its inside circulation cooling medium;Further include: liquid tank, for receiving and temporarily storing condensed liquid hydrofluoric acid mixture;Flow divider, including the first conduit and the second conduit of the main pipeline from the outlet end of liquid tank and the booster pump installed on the main pipeline;Valve assembly, including the first valve installed on the first conduit and used to control the opening and closing of the pipeline and the second valve installed on the second conduit and used to control the opening and closing of the pipeline;Concentration detector, for real-time detection of the hydrofluoric acid concentration of liquid hydrofluoric acid mixture in liquid tank;Controller, for receiving the detection signal of concentration detector, and according to the preset concentration threshold control the operating state of first valve, second valve and booster pump.

Description

Technical Field

[0001] This utility model belongs to the field of hydrofluoric acid recovery and purification technology, and specifically relates to a hydrofluoric acid recovery and purification device. Background Technology

[0002] Hydrofluoric acid, as an important chemical raw material, is widely used in many industrial fields, such as electronics, metallurgy, and glass processing. However, a large amount of hydrofluoric acid wastewater is inevitably generated during its production and use. If this wastewater is discharged directly without effective treatment, the hydrofluoric acid it contains will corrode soil and aquatic ecosystems, disrupt the ecological balance, and also result in a huge waste of hydrofluoric acid resources.

[0003] In existing technologies, graphite evaporators are frequently used for the evaporation, concentration, and recovery of hydrofluoric acid. The specific steps are as follows: the hydrofluoric acid stock solution is first preheated to a certain temperature using a condensate preheater. The preheated stock solution then enters the graphite evaporator for evaporation and concentration, using steam as the heat source. The concentrated hydrofluoric acid is then filtered and recycled. During the evaporation and concentration process, steam is generated, and azeotropes evaporate with the steam, resulting in the presence of acidic gases, such as hydrofluoric acid, in the steam. To ensure the purity of the recovered hydrofluoric acid and meet environmental requirements, the steam generated during evaporation needs to be purified. Common methods include using condensate evaporators... Condensation recovery involves cooling steam into liquid using a condenser to recover hydrofluoric acid and water. The condensed liquid can be returned to the evaporation system for further purification or used as a raw material for compounding. However, in this process, steam is continuously generated, and after being condensed and returned to the evaporator for reheating, evaporation, and condensation to form a liquid hydrofluoric acid mixture, the concentration of hydrofluoric acid in the liquid hydrofluoric acid mixture is unstable. If the liquefied hydrofluoric acid mixture with a low concentration is repeatedly returned to the evaporator for heating and concentration, it will not only lead to equipment damage but also to over-purification, affecting product profitability. Utility Model Content

[0004] To address the above problems, the purpose of this utility model is to provide a hydrofluoric acid recovery and purification device to solve the problems mentioned in the background art.

[0005] This utility model provides a hydrofluoric acid recovery and purification device, comprising: an evaporator for heating hydrofluoric acid wastewater to evaporate water and some hydrofluoric acid into steam; a distillation and purification device for reheating the concentrated hydrofluoric acid solution to separate hydrofluoric acid azeotropes; a steam collection pipe connected to the steam outlet of the evaporator for collecting hydrofluoric acid-containing steam generated by the evaporator; a condensation device with a cooling medium circulating inside for condensing the steam in the steam collection pipe to liquefy the steam into a liquid hydrofluoric acid mixture; and further comprising: a storage tank with its inlet connected to the steam collection pipe for receiving and temporarily storing the condensed liquid hydrofluoric acid mixture; and a distributor including a first conduit and a second conduit branching from the main pipe at the outlet of the storage tank, and a device installed on the... The system includes a booster pump on the main pipeline for powering liquid transport; the end of the first conduit is connected to the inlet of a distillation and purification device for transporting the liquid to be purified; the end of the second conduit is connected to the return port of the evaporator for returning the liquid to the evaporator; a valve assembly including a first valve installed on the first conduit for controlling the opening and closing of the pipeline and a second valve installed on the second conduit for controlling the opening and closing of the pipeline; a concentration detector installed on the storage tank for real-time detection of the hydrofluoric acid concentration of the liquid hydrofluoric acid mixture in the storage tank; and a controller electrically connected to the concentration detector, the first valve, the second valve, and the booster pump for receiving the detection signal from the concentration detector and controlling the operating status of the first valve, the second valve, and the booster pump according to a preset concentration threshold.

[0006] Preferably, the condensation device includes: a condenser tube, sleeved on the outside of the steam collection tube, with its two ends connected to the outlet and inlet of the cooling medium source, respectively; and a circulation pump, installed on the return pipe of the condenser tube, for driving the cooling medium to circulate.

[0007] Preferably, the device further includes a third valve installed at the end of the steam collection pipe near the liquid storage tank and a liquid level detector installed on the liquid storage tank. Both the liquid level detector and the third valve are connected to the controller, and the controller controls the opening and closing state of the third valve according to the liquid level signal detected by the liquid level detector.

[0008] Preferably, the valve assembly further includes a one-way valve installed on the side of the main pipeline near the storage tank.

[0009] Preferably, the concentration detector is an optical hydrofluoric acid concentration detector.

[0010] Preferably, the side of the vapor collection pipe closest to the liquid storage tank is designed in a continuous S-shape, and the shape of the condenser pipe is adapted to the vapor collection pipe.

[0011] Preferably, the distillation and purification equipment is a packed tower, with a total condenser at the top and a reboiler at the bottom.

[0012] The beneficial effects of this invention are as follows: By setting a concentration detector to monitor the concentration of the mixed liquid in the storage tank in real time, the controller automatically adjusts the operating status of the first valve (purification channel), the second valve (reflux channel), and the booster pump according to preset thresholds (such as low concentration ≤30% reflux, high concentration ≥80% purification), avoiding manual intervention and ensuring that the recovery process is accurately adapted to different concentration conditions. Through the graded treatment of evaporation concentration and distillation purification (low concentration reflux for secondary evaporation, high concentration enters distillation), water and other impurities can be efficiently separated, and finally high-purity hydrofluoric acid azeotrope (such as electronic grade HF) can be obtained, reducing resource waste. Attached Figure Description

[0013] Figure 1 This is a first-view structural diagram of the present invention; Figure 2 This is a schematic diagram of the second-view structure of the present invention; Figure 3 This is a three-dimensional structural diagram of the present invention with the distributor and the outer shell of the storage tank removed. Figure 4 This is a cross-sectional structural diagram of the present invention; Figure 5 This is an enlarged structural diagram of point A in this utility model.

[0014] In the diagram: 1. Evaporator; 2. Distillation and purification equipment; 3. Steam collection pipe; 4. Condensation equipment; 5. Liquid storage tank; 6. Flow divider; 7. Main pipeline; 8. First conduit; 9. Second conduit; 10. Booster pump; 11. First valve; 12. Second valve; 13. Controller; 14. Condenser; 15. Cooling medium source; 16. Circulation pump; 17. Third valve; 18. Check valve; 19. Packed tower; 20. Total condenser; 21. Reboiler. Detailed Implementation

[0015] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be described in detail below with reference to the accompanying drawings. The description in this part is only exemplary and explanatory, and should not be used to limit the scope of protection of this utility model in any way.

[0016] This utility model relates to an existing hydrofluoric acid recovery and purification device, which mainly includes an evaporator 1, such as a graphite evaporator 1, used to heat hydrofluoric acid wastewater, causing water and some hydrofluoric acid to evaporate and form steam. The hydrofluoric acid solution, after being concentrated by evaporation in the evaporator 1, is then reheated by a distillation and purification device 2 connected to the outlet of the evaporator 1, and hydrofluoric acid azeotropes are separated. During the evaporation and concentration process in the evaporator 1, the steam generated is collected through a steam collection pipe 3. This steam contains hydrofluoric acid. To avoid wasting hydrofluoric acid, a condenser 4 is used to condense the steam exiting from the steam collection pipe 3. The process involves condensation to liquefy the hydrofluoric acid into a liquid mixture for subsequent processing. However, during this process, steam is continuously generated. After the steam is condensed and returned to the evaporator for reheating, evaporation, and condensation to form a liquid hydrofluoric acid mixture, the concentration of hydrofluoric acid in the liquid mixture is unstable. Repeatedly returning the liquefied hydrofluoric acid mixture with a low concentration to the evaporator for heating and concentration will not only lead to equipment damage but also cause over-purification, affecting product profitability. Based on the above problems, this utility model adopts the following improvement method to solve them.

[0017] like Figure 1-5As shown, a hydrofluoric acid recovery and purification device, based on the above, adds a storage tank 5, whose inlet end is connected to a vapor collection pipe 3 for receiving and temporarily storing the condensed liquid hydrofluoric acid mixture. A first conduit 8 and a second conduit 9 branch off from the main pipe 7 connected to the outlet end of the storage tank 5. A booster pump 10 is also installed on the main pipe 7. The end of the first conduit 8 is connected to the inlet of the distillation and purification equipment 2 for transporting the liquid to be purified. A first valve 11 for controlling the opening and closing of the first conduit 8 is installed on the first conduit 8. The end of the second conduit 9 is connected to the return port of the evaporator 1 for returning the liquid to the evaporator 1. Correspondingly, a second valve for controlling the opening and closing of the second conduit 9 is also installed on the second conduit 9. 12. When the liquefied hydrofluoric acid mixture needs to be returned to evaporator 1, the second valve 12 opens and the first valve 11 closes. When the liquefied hydrofluoric acid mixture needs to enter the distillation and purification equipment 2 for processing, the first valve 11 opens and closes, and the second valve 12 closes. To accurately control the opening and closing timing of the first valve 11 and the second valve 12, a concentration detector is installed on the storage tank 5 containing the hydrofluoric acid mixture. This concentration detector uses an optical method (near-infrared / mid-infrared spectroscopy) hydrofluoric acid concentration detector, which quantitatively analyzes the concentration through the characteristic absorption peaks of HF molecules (such as the near-infrared 1300-1500nm band). It is not affected by the conductivity of other ions in the solution (such as a small amount of metal impurities), and the detection accuracy is high. The accuracy is ±0.5% to ±1% (better than ±2% to ±5% of the conductivity method), ensuring the accuracy and reliability of the concentration signal received by the controller 13. Because hydrofluoric acid is corrosive, optical sensors typically measure indirectly through corrosion-resistant windows (such as sapphire or quartz) or fiber optic probes to avoid direct contact with the corrosive HF liquid, reducing sensor wear (conductivity electrodes are easily blocked by HF crystals) and extending the lifespan of the detection element. This is used for real-time detection of the hydrofluoric acid concentration in the liquid hydrofluoric acid mixture within the storage tank 5. Furthermore, to reduce manual intervention, the concentration detector is electrically connected to the controller 13. The concentration detector transmits the detected hydrofluoric acid concentration in the liquid hydrofluoric acid mixture to the controller 13, which then determines the concentration based on the pre-defined concentration in the hydrofluoric acid mixture. The opening and closing of the first valve 11 and the second valve 12, as well as the operation of the booster pump 10, are controlled by a hydrofluoric acid concentration threshold. Specifically, when the concentration detector detects that the concentration of hydrofluoric acid in the hydrofluoric acid mixture in the storage tank 5 is ≤30%, the controller 13 controls the opening and closing of the booster pump 10, the first valve 11 is opened, and the second valve 12 is closed, so that the hydrofluoric acid mixture is transported to the distillation and purification equipment 2 through the first conduit 8 for subsequent processing. In this technical solution, the distillation and purification equipment 2 is a packed tower 19. A total condenser 20 is set at the top of the packed tower 19 and a reboiler 21 is set at the bottom of the tower. The packed tower 19 increases the gas-liquid contact area through the packing material (such as Pall rings and wire mesh corrugated packing) to promote the efficient separation of HF azeotropes and impurities.The total condenser 20 completely liquefies the top vapor of the column, recovering high-purity HF (e.g., ≥99% concentration). The reboiler 21 at the bottom of the column reheats the residual concentrate for further purification or concentration, ensuring that the final product meets the requirements of industrial or electronic applications. When the concentration detector detects that the concentration of hydrofluoric acid in the hydrofluoric acid mixture in the storage tank 5 is ≥80%, the controller 13 controls the opening and closing of the booster pump 10, the first valve 11 closes, and the second valve 12 opens, transporting the hydrofluoric acid mixture through the second conduit 9 to the evaporator 1 for reheating and concentration. This efficiently separates water and other impurities, ultimately obtaining a high-purity hydrofluoric acid azeotrope (e.g., electronic-grade HF), reducing resource waste. To improve the accuracy of the concentration detector, a third valve 17 is installed at the end of the steam collection pipe 3 near the storage tank 5. A level detector, such as an ultrasonic level sensor, is also installed on the storage tank 5. The liquid level detector and the third valve 17 are all connected to the controller 13. The controller 13 controls the opening and closing of the third valve 17 according to the liquid level signal detected by the liquid level detector. When the liquid level sensor detects that the liquid level in the storage tank 5 reaches the first preset threshold, the controller 13 controls the third valve 17 to close. The controller 13 distributes the detected liquid hydrofluoric acid mixture in the storage tank 5 according to the concentration of hydrofluoric acid in the liquid hydrofluoric acid mixture detected by the concentration detector. When the liquid level in the storage tank 5 is lower than the second preset threshold, it means that the hydrofluoric acid mixture in the storage tank 5 has been distributed. At this time, the controller 13 controls the opening and closing of the third valve 17 to allow the liquefied hydrofluoric acid mixture to flow into the storage tank 5. The above operation is repeated. Because the amount of liquid hydrofluoric acid mixture after steam liquefaction is small, there will be no blockage or leakage of the steam collection pipe 3. Furthermore, during the transport of the liquefied hydrofluoric acid mixture through the first conduit 8 or the second conduit 9, a one-way valve 18 is installed on the side of the main pipeline 7 near the storage tank 5 to prevent liquid backflow into the storage tank 5. This valve allows liquid to flow only towards the booster pump 10. When the booster pump 10 stops operating or the downstream pipeline pressure is abnormal (such as a malfunction in the distillation and purification equipment 2 causing an increase in backflow pressure), the one-way valve 18 automatically closes to prevent the mixture from flowing back into the storage tank 5 through the main pipeline 7, thus avoiding affecting the accuracy of the concentration detector.

[0018] Furthermore, such as Figure 3-5 As shown, in this technical solution, the condensing equipment 4 mainly consists of a condensing pipe 14 sleeved outside the steam collecting pipe 3 and a circulating pump 16. The two ends of the condensing pipe 14 are connected to the outlet and inlet of the cooling medium source 15 (such as a device storing water or ethylene glycol solution), respectively. The circulating pump 16 is installed on the return pipe of the condensing pipe 14 to drive the cooling medium to circulate. Figure 3 As shown, the side of the steam collecting pipe 3 closest to the liquid storage tank 5 is designed as a continuous S-shape, and the shape of the condenser pipe 14 is adapted to the steam collecting pipe 3, which can prolong the residence time of steam in the steam collecting pipe 3 and improve the liquefaction effect.

[0019] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0020] This article uses specific examples to illustrate the principles and implementation methods of this utility model. The above examples are only for the purpose of helping to understand the method and core ideas of this utility model. The above description is only a preferred embodiment of this utility model. It should be noted that due to the limitations of textual expression, there are objectively infinite specific structures. For those skilled in the art, several improvements, modifications, or changes can be made without departing from the principles of this utility model, and the above technical features can also be combined in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the protection scope of this utility model.

Claims

1. A hydrofluoric acid recovery and purification device, comprising: Evaporator (1) is used to heat hydrofluoric acid wastewater to evaporate water and some hydrofluoric acid to form steam; Distillation and purification equipment (2) is used to reheat the concentrated hydrofluoric acid solution to separate the hydrofluoric acid azeotrope; A steam collection pipe (3) is connected to the steam outlet of the evaporator (1) and is used to collect hydrofluoric acid vapor generated by the evaporator (1); The condensing device (4) has a cooling medium circulating inside it, which is used to condense the steam in the steam collection pipe (3) to liquefy the steam into a liquid hydrofluoric acid mixture. Its characteristic is that it further includes: The liquid storage tank (5) is connected to the vapor collection pipe (3) at its inlet end, and is used to receive and temporarily store the condensed liquid hydrofluoric acid mixture. The distributor (6) includes a first conduit (8) and a second conduit (9) branching off from the main pipe (7) at the outlet end of the liquid storage tank (5), and a booster pump (10) installed on the main pipe (7) for providing power for liquid transportation. The end of the first conduit (8) is connected to the inlet of the distillation and purification equipment (2) for transporting the liquid to be purified; the end of the second conduit (9) is connected to the return port of the evaporator (1) for returning the liquid to the evaporator (1). The valve assembly includes a first valve (11) mounted on the first conduit (8) for controlling the opening and closing of the conduit and a second valve (12) mounted on the second conduit (9) for controlling the opening and closing of the conduit. A concentration detector is installed on the storage tank (5) to detect the concentration of hydrofluoric acid in the liquid hydrofluoric acid mixture in the storage tank (5) in real time. The controller (13) is electrically connected to the concentration detector, the first valve (11), the second valve (12) and the booster pump (10), and is used to receive the detection signal from the concentration detector and control the operating status of the first valve (11), the second valve (12) and the booster pump (10) according to the preset concentration threshold.

2. The hydrofluoric acid recovery and purification device according to claim 1, characterized in that: The condensation device (4) includes: A condenser tube (14) is sleeved on the outside of the steam collection tube (3), and its two ends are respectively connected to the outlet and inlet of the cooling medium source (15); A circulation pump (16) is installed on the return line of the condenser (14) to drive the cooling medium to circulate.

3. The hydrofluoric acid recovery and purification device according to claim 1, characterized in that: It also includes a third valve (17) installed on the end of the steam collection pipe (3) near the liquid storage tank (5) and a liquid level detector installed on the liquid storage tank (5). The liquid level detector and the third valve (17) are both connected to the controller (13). The controller (13) controls the opening and closing state of the third valve (17) according to the liquid level signal detected by the liquid level detector.

4. The hydrofluoric acid recovery and purification device according to claim 1, characterized in that: The valve assembly also includes a check valve (18) installed on the side of the main pipe (7) near the storage tank (5).

5. The hydrofluoric acid recovery and purification device according to claim 1, characterized in that: The concentration detector is an optical hydrofluoric acid concentration detector.

6. The hydrofluoric acid recovery and purification device according to claim 2, characterized in that: The side of the steam collection pipe (3) near the liquid storage tank (5) is designed as a continuous S-shape, and the shape of the condenser pipe (14) is adapted to the steam collection pipe (3).

7. The hydrofluoric acid recovery and purification device according to claim 1, characterized in that: The distillation and purification equipment (2) is a packed tower (19), with a total condenser (20) installed at the top of the packed tower (19) and a reboiler (21) installed at the bottom.

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