Hydrogen fluoride recovery device

Abstract

The invention discloses a hydrogen fluoride recovery device, and relates to the technical field of chemical equipment. The hydrogen fluoride recovery device comprises a flash tank, a heater, a circulation driving part, a negative pressure generator and a first washing assembly, the flash tank is provided with a first liquid outlet, a liquid return port and a first exhaust port, and the heater is connected with the first liquid outlet and the liquid return port and used for heating a medium flowing through the heater. The circulation driving part is connected with the heater in series and used for driving a medium in the flash tank to flow to the heater, the negative pressure generator is connected with the first exhaust port and used for extracting gas in the flash tank so as to generate negative pressure in the flash tank, the first washing assembly comprises a first washing tower, the first washing tower is provided with a first inlet, and the first inlet is connected with the negative pressure generator; the first washing tower is used for washing gas discharged by the negative pressure generator. According to the hydrogen fluoride recovery device, the working temperature can be reduced, and the operation reliability can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical equipment, and particularly to a hydrogen fluoride recovery device. Background Art

[0002] In the related art, fluosilicic acid is decomposed by sulfuric acid to prepare hydrogen fluoride. The fluosilicic acid is thermally decomposed into hydrogen fluoride and silicon tetrafluoride in a decomposition tower. Most of the hydrogen fluoride dissolves in sulfuric acid in the decomposition tower. Therefore, it is necessary to evaporate the fluorine-containing sulfuric acid and wash the hydrogen fluoride to recover the hydrogen fluoride. However, the working temperature required for atmospheric evaporation of the fluorine-containing sulfuric acid is relatively high, resulting in extremely difficult long-term safe and reliable operation of the device for recovering hydrogen fluoride, which greatly affects the operation reliability of the recovery device. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to some extent.

[0004] To this end, an object of the present invention is to provide a hydrogen fluoride recovery device, which can reduce the working temperature and improve the operation reliability.

[0005] According to an embodiment of the present invention, the hydrogen fluoride recovery device includes a flash tank, a heater, a circulation driving member, a negative pressure generator, and a first washing assembly. The flash tank is provided with a first liquid discharge port, a liquid return port, and a first exhaust port. The heater is connected to the first liquid discharge port and the liquid return port and is used to heat the medium flowing through the heater. The circulation driving member is connected in series with the heater and is used to drive the medium in the flash tank to flow to the heater. The negative pressure generator is connected to the first exhaust port and is used to extract the gas in the flash tank to create a negative pressure in the flash tank. The first washing assembly includes a first washing tower. The first washing tower is provided with a first inlet. The first inlet is connected to the negative pressure generator. The first washing tower is used to wash the gas discharged from the negative pressure generator.

[0006] According to the embodiment of the present invention, the hydrogen fluoride recovery device can reduce the working temperature and improve the operation reliability.

[0007] In addition, according to the hydrogen fluoride recovery device of the above embodiment of the present invention, the following additional technical features may further be included: Optionally, the negative pressure generator is configured such that the pressure P' created in the flash tank satisfies: -0.06 MPa ≤ P' ≤ -0.01 MPa; and / or, the negative pressure generator is configured such that the working pressure P in its negative pressure zone and the pressure P' it creates in the flash tank satisfy: P ≤ 2 × P'.

[0008] Optionally, the first scrubbing tower further has a second liquid discharge port. The negative pressure generator includes a Venturi ejector and a medium driver. The Venturi ejector has a high-pressure inlet, a low-pressure inlet, and a mixing outlet. The low-pressure inlet is connected to the first exhaust port, the mixing outlet is connected to the first inlet, the high-pressure inlet is connected to the second liquid discharge port, and the medium driver is connected in series between the second liquid discharge port and the high-pressure inlet and is used to drive the scrubbing medium in the first scrubbing tower to flow towards the high-pressure inlet; Alternatively, the hydrogen fluoride recovery device further includes a liquid storage tank for storing the scrubbing medium. The high-pressure inlet is connected to the liquid storage tank, and the medium driver is connected in series between the liquid storage tank and the high-pressure inlet and is used to drive the scrubbing medium in the liquid storage tank to flow towards the high-pressure inlet.

[0009] Optionally, the first scrubbing tower further has a third liquid discharge port and a second exhaust port. The first scrubbing assembly further includes a first spraying structure and a first driver. The first driver is connected between the third liquid discharge port and the first spraying structure and is used to drive the scrubbing medium in the first scrubbing tower to flow towards the first spraying structure. The first spraying structure is arranged in the first scrubbing tower and is used to spray the gas flowing towards the second exhaust port.

[0010] Optionally, the first scrubbing tower includes a first tower section and a second tower section. The first tower section is arranged above the second tower section, and the cross-sectional area of the first tower section is smaller than that of the second tower section. The second exhaust port is formed at the top of the first tower section. The first spraying structure is arranged in the first tower section and is located below the second exhaust port. The first spraying structure includes a plurality of spraying units arranged at intervals from top to bottom, and each spraying unit includes at least one spiral nozzle.

[0011] Optionally, the first scrubbing assembly further includes a second driver. The inlet of the second driver is connected to the first scrubbing tower, and the outlet of the second driver is adapted to be connected to a decomposition tower for decomposing fluorosilicic acid, so that the second driver is used to drive the scrubbing medium in the first scrubbing tower to flow towards the decomposition tower.

[0012] Optionally, the negative pressure generator includes a gas driver. The gas driver is connected to the first inlet and is used to drive the gas in the flash tank to be discharged towards the first scrubbing tower.

[0013] Optionally, the hydrogen fluoride recovery device further includes a second washing assembly to an nth washing assembly. The mth washing assembly includes an mth washing tower and an mth driving structure. The mth driving structure is connected to the mth inlet of the mth washing tower and the (m - 1)th washing tower, and is configured to drive the gas in the (m - 1)th washing tower to be discharged to the mth washing tower for washing. n≥2 and is a positive integer, 2≤m≤n, and m is a positive integer.

[0014] Optionally, the structure of the mth washing assembly is the same as that of the first washing assembly.

[0015] Optionally, the structure of the mth driving structure is the same as that of the negative pressure generator.

[0016] Optionally, the heater is a block hole type silicon carbide heat exchanger. Description of the Drawings

[0017] Figure 1 is a schematic diagram of a hydrogen fluoride recovery device in some embodiments of the present invention.

[0018] Figure 2 is a partial schematic diagram of a hydrogen fluoride recovery device in some other embodiments of the present invention.

[0019] Reference Signs: Hydrogen fluoride recovery device 100, flash tank 10, first liquid discharge port 11, liquid return port 12, first exhaust port 13, liquid inlet port 14, heater 20, circulation driving member 30, negative pressure generator 40, venturi ejector 41, high-pressure inlet 411, low-pressure inlet 412, mixing outlet 413, medium driving member 42, first washing assembly 50, first washing tower 51, first inlet 511, second liquid discharge port 512, third liquid discharge port 513, second exhaust port 514, first tower section 515, second tower section 516, first spraying structure 52, spraying unit 521, first driving member 53, second driving member 54, second washing assembly 60. Detailed Description of the Embodiments

[0020] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where 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 drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0021] In the related art, hydrogen fluoride is prepared by the sulfuric acid decomposition method of fluosilicic acid. The fluosilicic acid is thermally decomposed into hydrogen fluoride and silicon tetrafluoride in a decomposition tower. Most of the hydrogen fluoride dissolves in sulfuric acid in the decomposition tower. Therefore, it is necessary to evaporate the fluorine-containing sulfuric acid and wash the hydrogen fluoride to recover the hydrogen fluoride. However, the working temperature required for the atmospheric evaporation of the fluorine-containing sulfuric acid is relatively high. For example, a working temperature of 170 °C is required to recover 90% of the hydrogen fluoride, resulting in extremely difficult long-term safe and reliable operation of the device required for the recovery of hydrogen fluoride, which greatly affects the reliability of the recovery device.

[0022] Therefore, the present invention proposes a hydrogen fluoride recovery device 100, which can reduce the working temperature and improve the reliability of operation.

[0023] As Figure 1 and Figure 2 , in some embodiments of the present invention, the hydrogen fluoride recovery device 100 includes a flash tank 10, a heater 20, a circulation driving member 30, and a negative pressure generator 40.

[0024] Among them, the flash tank 10 is provided with a first liquid discharge port 11, a liquid return port 12, and a first exhaust port 13. The heater 20 is connected to the first liquid discharge port 11 and the liquid return port 12. The heater 20 is used to heat the medium flowing through the heater 20. The circulation driving member 30 is connected in series with the heater 20, and the circulation driving member 30 is used to drive the medium in the flash tank 10 to flow to the heater 20. The negative pressure generator 40 is connected to the first exhaust port 13 and is used to extract the gas in the flash tank 10 to create a negative pressure in the flash tank 10. With such a setting, the working temperature can be reduced and the reliability of operation can be improved.

[0025] The working principle of the hydrogen fluoride recovery device 100: When the hydrogen fluoride recovery device 100 is in use, the flash tank 10 can contain fluorosulfuric acid, or other equipment can introduce fluorosulfuric acid into the flash tank 10. For example, the flash tank 10 is provided with a liquid inlet 14, and the liquid inlet 14 is connected to the decomposition tower, so that the fluorosulfuric acid in the decomposition tower can be discharged into the flash tank 10 through the liquid inlet 14; the first liquid discharge port 11 and the liquid return port 12 of the flash tank 10 are respectively connected to the heater 20, so that a circulation loop is formed by connecting the flash tank 10 and the heater 20. The circulation driving member 30 can drive the fluorosulfuric acid to circulate between the flash tank 10 and the heater 20. Then, the fluorosulfuric acid in the flash tank 10 flows out through the first liquid discharge port 11 and flows back to the flash tank 10 through the liquid return port 12 after flowing through the heater 20. The fluorosulfuric acid is heated by the heater 20 and undergoes flashing in the flash tank 10 to evaporate hydrogen fluoride gas; during this process, the negative pressure generator 40 extracts the gas in the flash tank 10, so that the pressure in the flash tank 10 decreases, and the flash tank 10 is in a negative pressure state (negative pressure is a gas pressure state lower than atmospheric pressure, and atmospheric pressure is the so-called one atmosphere). As a result, the boiling point of the fluorosulfuric acid decreases, and the fluorosulfuric acid can evaporate hydrogen fluoride gas at a lower temperature (for example, 140 °C or below 140 °C), and is discharged from the flash tank 10 through the first exhaust port 13 under the action of the negative pressure generator 40; thus, under the action of the negative pressure generator 40, the working temperature of the hydrogen fluoride recovery device 100 can be reduced, which is beneficial to reducing the requirements for the high-temperature resistance performance of the materials of the hydrogen fluoride recovery device 100 (such as the flash tank 10, the heater 20, and the circulation driving member 30), and is beneficial to reducing the power consumption of the heater 20. The heater 20 does not need to heat the fluorosulfuric acid to a higher temperature, and at the same time improves the operation reliability of the hydrogen fluoride recovery device 100.

[0026] As Figure 1 and Figure 2 shown, in some embodiments of the present invention, the hydrogen fluoride recovery device 100 further includes a first washing assembly 50. The first washing assembly 50 includes a first washing tower 51. The first washing tower 51 is provided with a first inlet 511, and the first inlet 511 is connected to the negative pressure generator 40. The first washing tower 51 is used to wash the gas discharged by the negative pressure generator 40; it can be understood that the hydrogen fluoride gas evaporated from the fluorosulfuric acid in the flash tank 10 entangles some impurities. The hydrogen fluoride gas needs to be discharged into the washing tower through the first inlet 511, and the first washing tower 51 is used to wash the hydrogen fluoride gas to improve the recovery efficiency of hydrogen fluoride.

[0027] Exemplarily, the hydrogen fluoride gas evaporated from the flash tank 10 entrains some moisture. Sulfuric acid can be used as the washing medium in the first washing tower 51 to remove the moisture in the hydrogen fluoride gas. It should be understood that the hydrogen fluoride gas is evaporated by heating the fluorosulfuric acid. Therefore, the temperature of the hydrogen fluoride gas entering the first washing tower 51 is relatively high and it is not easy to redissolve in the sulfuric acid. Therefore, sulfuric acid can be used as the washing medium, and the sulfuric acid after washing can be easily recycled and used to continue preparing hydrogen fluoride from fluorosilicic acid in the decomposition tower, reducing waste and improving utilization rate.

[0028] In addition, optionally, a liquid discharge driving member may be connected to the first liquid discharge port 11, and the first liquid discharge port 11 may be selectively communicated with the circulation driving member 30 and the liquid discharge driving member; when it is necessary to evaporate the fluorosulfuric acid, the first liquid discharge port 11 may be communicated with the circulation driving member 30; when it is necessary to discharge the sulfuric acid in the evaporation tube, the first liquid discharge port 11 may be communicated with the liquid discharge driving member.

[0029] In some embodiments of the present invention, the negative pressure generator 40 is configured such that the pressure P' created in the flash tank 10 satisfies: -0.06 MPa ≤ P' ≤ -0.01 MPa, so as to reliably achieve flashing of the medium in the flash tank 10 at a relatively low temperature. For example, when the flash tank 10 contains fluorosulfuric acid, the heater 20 can heat the fluorosulfuric acid to 140 °C or below to achieve flashing; and / or, the negative pressure generator 40 is configured such that the working pressure P in its negative pressure zone and the pressure P' it creates in the flash tank 10 satisfy: P ≤ 2 × P', so as to still enable the negative pressure generator 40 to create a reliable negative pressure in the flash tank 10 while the heater 20 heats the medium to achieve flashing. Moreover, the above settings can be applied to more types of pipe arrangements between the heater 20 and the flash tank 10, and can also be applied to more types of flash tanks 10 with different volumes, different flashing amounts, etc., which is beneficial to improving the applicability of the hydrogen fluoride recovery device 100.

[0030] Exemplarily, P' can be -0.01 MPa, -0.02 MPa, -0.03 MPa, -0.04 MPa, -0.05 MPa, -0.06 MPa, etc.; P can be 2 × P', 2.2 × P', 2.5 × P', 2.7 × P', 3 × P', 3.5 × P' or 4 × P', etc.

[0031] In some embodiments of the present invention, the negative pressure generator 40 is configured such that the working pressure P in its negative pressure region satisfies: P ≤ -0.04 MPa; it can be understood that the negative pressure generator 40 generates negative pressure in its negative pressure region and, through the first exhaust port 13 of the flash tank 10, generates negative pressure inside the flash tank 10, thereby reducing the boiling point of the fluorosulfuric acid. Therefore, in order to keep the pressure value inside the flash tank 10 stable below atmospheric pressure, the working pressure P in the negative pressure region of the negative pressure generator 40 needs to satisfy: P ≤ -0.04 MPa, so as to reduce the working temperature of the hydrogen fluoride recovery device 100 and improve the operation stability of the hydrogen fluoride recovery device 100.

[0032] Regarding the principle of negative pressure generation of the negative pressure generator 40, the negative pressure generator 40 may include an ejector, a vacuum pump, etc.; for example, the negative pressure generator 40 includes a Venturi ejector 41. At this time, the negative pressure generator 40 can utilize the Venturi effect, that is, by allowing a fluid to flow rapidly through the negative pressure generator 40 to generate negative pressure inside the flash tank 10. In the following description, the case where the negative pressure generator 40 includes a Venturi ejector 41 is taken as an example for illustration. After those skilled in the art read the following solution, it is easy to understand the implementation schemes of the negative pressure generator 40 as other structures that can create negative pressure inside the flash tank 10. The present invention specifically provides the following implementation manners for illustration: Embodiment 1 The negative pressure generator 40 generates negative pressure inside the flash tank 10 by means of the washing medium inside the first washing tower 51.

[0033] Specifically, as Figure 1 and Figure 2 , the first washing tower 51 further has a second drain port 512. The negative pressure generator 40 includes a Venturi ejector 41 and a medium driving member 42. The Venturi ejector 41 has a high-pressure inlet 411, a low-pressure inlet 412, and a mixing outlet 413. The low-pressure inlet 412 is connected to the first exhaust port 13, the mixing outlet 413 is connected to the first inlet 511, the high-pressure inlet 411 is connected to the second drain port 512, and the medium driving member 42 is connected in series between the second drain port 512 and the high-pressure inlet 411. Moreover, the medium driving member 42 is used to drive the washing medium inside the first washing tower 51 to flow towards the high-pressure inlet 411; thus, negative pressure can be generated inside the flash tank 10 by means of the flow of the washing medium, and the hydrogen fluoride gas can be pre-washed to improve the recovery efficiency of hydrogen fluoride.

[0034] Specifically, the high-pressure inlet 411 and the mixing outlet 413 of the Venturi ejector 41 are respectively connected to the second liquid discharge port 512 and the first inlet 511 of the first scrubbing tower 51, so that the Venturi ejector 41 and the first scrubbing tower 51 are connected to form a circulation loop. The medium driving member 42 drives the scrubbing medium to circulate between the first scrubbing tower 51 and the Venturi ejector 41, thereby forming a negative pressure zone in the Venturi ejector 41. The negative pressure zone communicates with the low-pressure inlet 412 of the Venturi ejector 41 to generate a negative pressure in the flash tank 10, facilitating the evaporation of hydrogen fluoride gas from the fluorosulfuric acid at a relatively low temperature. Moreover, the Venturi ejector 41 can suck the hydrogen fluoride gas in the flash tank 10 into its negative pressure zone, mix the hydrogen fluoride gas with the scrubbing medium for preliminary scrubbing, and then the mixed medium is discharged to the first scrubbing tower 51 through the mixing outlet 413. In this way, the hydrogen fluoride gas can be pre-scrubbed by the Venturi ejector 41 before entering the first scrubbing tower 51, improving the recovery efficiency of hydrogen fluoride.

[0035] Embodiment 2 The negative pressure generator 40 generates a negative pressure in the flash tank 10 by means of the scrubbing medium introduced from the liquid storage tank into the first scrubbing tower 51.

[0036] In some other embodiments of the present invention, the first scrubbing tower 51 further has a second liquid discharge port 512. The negative pressure generator 40 includes a Venturi ejector 41 and a medium driving member 42. The Venturi ejector 41 has a high-pressure inlet 411, a low-pressure inlet 412, and a mixing outlet 413. The low-pressure inlet 412 is connected to the first exhaust port 13, and the mixing outlet 413 is connected to the first inlet 511. The hydrogen fluoride recovery device 100 further includes a liquid storage tank for storing the scrubbing medium. The high-pressure inlet 411 is connected to the liquid storage tank, and the medium driving member 42 is connected in series between the liquid storage tank and the high-pressure inlet 411, and the medium driving member 42 is used to drive the scrubbing medium in the liquid storage tank to flow towards the high-pressure inlet 411. Thus, a negative pressure can be generated in the flash tank 10 by means of the flow of the scrubbing medium, and the hydrogen fluoride gas can also be pre-scrubbed by the Venturi ejector 41, improving the recovery efficiency of hydrogen fluoride.

[0037] Specifically, the high-pressure inlet 411 and the mixing outlet 413 of the Venturi ejector 41 are respectively connected to the liquid storage tank and the first inlet 511 of the first scrubbing tower 51. The medium driving member 42 drives the scrubbing medium to flow from the liquid storage tank into the first scrubbing tower 51, thereby forming a negative pressure zone in the Venturi ejector 41. The negative pressure zone communicates with the low-pressure inlet 412 of the Venturi ejector 41 to generate a negative pressure in the flash tank 10, facilitating the evaporation of hydrogen fluoride gas from the fluorosulfuric acid at a relatively low temperature. Moreover, the Venturi ejector 41 can suck the hydrogen fluoride gas in the flash tank 10 into its negative pressure zone, mix the hydrogen fluoride gas with the scrubbing medium for preliminary scrubbing, and then the mixed medium is discharged to the first scrubbing tower 51 through the mixing outlet 413. In this way, the hydrogen fluoride gas can be pre-scrubbed by the Venturi ejector 41 before entering the first scrubbing tower 51, improving the recovery efficiency of hydrogen fluoride.

[0038] It can be seen that in the above-described Embodiment 1 and Embodiment 2, regardless of whether the scrubbing medium driven by the medium driving member 42 flowing into the Venturi ejector 41 comes from the first scrubbing tower 51 or the liquid storage tank, it can be pre-scrubbed by the Venturi ejector 41 before the hydrogen fluoride flows to the first scrubbing tower 51. It can be understood that by using other types of ejectors, pre-scrubbing can also be performed by the ejector before the hydrogen fluoride flows to the first scrubbing tower 51.

[0039] In some embodiments of the present invention, the working pressure P of the negative pressure zone in the Venturi ejector 41 satisfies: -0.09 MPa ≤ P ≤ -0.04 MPa; it can be understood that if the working pressure P of the negative pressure zone in the Venturi ejector 41 > -0.04 MPa, it is likely to limit the specifications of the flash tank 10 matching the Venturi ejector 41, resulting in limited use of the hydrogen fluoride recovery device 100; if the working pressure of the negative pressure zone in the Venturi ejector 41 < -0.09 MPa, the requirements for the Venturi ejector 41 are too high, easily exceeding the working load of the Venturi ejector 41, causing the Venturi ejector 41 to be in an extreme operating state for a long time and the operating condition to be unstable. Therefore, the working pressure P of the negative pressure zone in the Venturi ejector 41 can be made to satisfy: -0.09 MPa ≤ P ≤ -0.04 MPa. In this way, while ensuring the stable operation of the Venturi ejector 41, a negative pressure can be generated in the flash tank 10, facilitating the reduction of the evaporation temperature of the fluorosulfuric acid, thereby improving the working stability of the hydrogen fluoride recovery device 100.

[0040] Such as Figure 1 and Figure 2, in some embodiments of the present invention, the first scrubbing tower 51 further has a third liquid discharge port 513 and a second exhaust port 514. The first scrubbing assembly 50 further includes a first spraying structure 52 and a first driving member 53. The first driving member 53 is connected between the third liquid discharge port 513 and the first spraying structure 52, and the first driving member 53 is used to drive the scrubbing medium in the first scrubbing tower 51 to flow towards the first spraying structure 52. The first spraying structure 52 is arranged in the first scrubbing tower 51, and the first spraying structure 52 is used to spray the gas flowing towards the second exhaust port 514; thus, impurities in the hydrogen fluoride gas can be removed to achieve the purpose of recovering the hydrogen fluoride gas.

[0041] Exemplarily, the hydrogen fluoride gas evaporated from the fluorosulfuric acid contains some moisture. Therefore, sulfuric acid can be introduced into the first scrubbing tower 51 as a scrubbing medium to wash the hydrogen fluoride gas to reduce the moisture in the hydrogen fluoride gas; wherein, a first spraying structure 52 and a first driving member 53 are arranged in the first scrubbing tower 51, and the first driving member 53 drives the scrubbing medium in the first scrubbing tower 51 to flow towards the first spraying structure 52, and the gas flowing towards the second exhaust port 514 is spray-washed through the first spraying structure 52, thereby removing the moisture in the hydrogen fluoride gas.

[0042] Such as Figure 1 and Figure 2 , in some embodiments of the present invention, the first scrubbing tower 51 includes a first tower section 515 and a second tower section 516. The first tower section 515 is arranged above the second tower section 516, and the cross-sectional area of the first tower section 515 is smaller than that of the second tower section 516. The second exhaust port 514 is formed at the top of the first tower section 515. The first spraying structure 52 is arranged in the first tower section 515, and the first spraying structure 52 is located below the second exhaust port 514. It can be understood that the second tower section 516 can be used to provide a containing space for sulfuric acid, and the first tower section 515 can be used to reduce the cross-sectional area of the hydrogen fluoride gas flow, facilitating the first spraying structure 52 to spray and wash the hydrogen fluoride gas and improving the impurity removal effect.

[0043] In addition, the first spraying structure 52 may include a plurality of spraying units 521 arranged at intervals from top to bottom (for example Figure 1 the first spraying structure 52 in [example] includes two spraying units 521 arranged at an interval from top to bottom), and each spraying unit 521 includes at least one spiral nozzle; thus, through the plurality of spraying units 521 arranged up and down, multi-stage spraying of the hydrogen fluoride gas can be realized to further improve the impurity removal effect of the hydrogen fluoride gas; and the coverage range of the spraying liquid sprayed by the spraying unit 521 is not less than the cross-sectional area of the tower section where the spraying unit 521 is located to ensure the spraying effect of the spraying unit 521 on the hydrogen fluoride gas.

[0044] Such as Figure 1 and Figure 2, in some embodiments of the present invention, the first washing assembly 50 further includes a second driving member 54. The inlet of the second driving member 54 is connected to the first washing tower 51, and the outlet of the second driving member 54 is adapted to be connected to a decomposition tower for decomposing fluosilicic acid, so that the second driving member 54 is used to drive the washing medium in the first washing tower 51 to flow towards the decomposition tower; in this way, waste can be reduced and the recycling rate of the recovered washing medium can be improved.

[0045] It can be understood that hydrogen fluoride is prepared in the decomposition tower by the sulfuric acid decomposition method of fluosilicic acid, and most of the generated hydrogen fluoride is dissolved in sulfuric acid. Therefore, it is necessary to perform an evaporation operation on the fluorine-containing sulfuric acid to evaporate the hydrogen fluoride therein and wash the hydrogen fluoride to achieve the recovery of hydrogen fluoride; in combination with the foregoing, sulfuric acid can be used as the washing medium in the first washing tower 51 to wash the hydrogen fluoride gas. After the washing is completed, it can flow back into the decomposition tower under the drive of the second driving member 54 to achieve the purpose of recycling the washing medium.

[0046] As an example, when the hydrogen fluoride recovery device 100 is in use, the outlet of the second driving member 54 is connected to the decomposition tower. The decomposition tower can decompose fluosilicic acid by the sulfuric acid method to prepare hydrogen fluoride. The flash tank 10 is provided with a liquid inlet 14, and the liquid inlet 14 is connected to the decomposition tower, so that the fluorine-containing sulfuric acid in the decomposition tower can be discharged to the flash tank 10 through the liquid inlet 14. In this way, a cycle is formed between the hydrogen fluoride recovery device 100 and the decomposition tower.

[0047] In addition, exemplarily, fluosilicic acid reacts with 95% sulfuric acid in the decomposition tower to prepare hydrogen fluoride, and the venturi ejector 41 generates a negative pressure through the flow of 98% sulfuric acid to drive the hydrogen fluoride gas in the flash tank 10 to flow towards the first washing tower 51. In the venturi ejector 41, 98% sulfuric acid washes the hydrogen fluoride gas and absorbs the moisture in the hydrogen fluoride gas to become 95% sulfuric acid. Similarly, 98% sulfuric acid is used in the first washing tower 51 to wash the hydrogen fluoride gas and absorb the moisture in the hydrogen fluoride gas to become 95% sulfuric acid. Finally, under the action of the second driving member 54, the 95% sulfuric acid in the first washing tower 51 can flow back into the decomposition tower. In this way, the recycling of the washing medium can be realized and waste can be reduced.

[0048] In some embodiments of the present invention, the negative pressure generator 40 includes a gas driving member, and the gas driving member is connected to the first inlet 511 and is used to drive the gas in the flash tank 10 to flow towards the first washing tower 51; it can be understood that the gas driving member drives the gas in the flash tank 10 to flow towards the first washing tower 51 to create a negative pressure in the flash tank 10. In this way, the evaporation temperature of the fluorine-containing sulfuric acid in the flash tank 10 can be reduced, and the working stability of the hydrogen fluoride recovery device 100 can be improved.

[0049] More preferably, the inner lining of the gas driving member is made of a material with high temperature resistance and corrosion resistance. For example, silicon carbide material is used.

[0050] For example Figure 2 Figure 2 In some embodiments of the present invention, the hydrogen fluoride recovery device 100 further includes a second washing assembly 60 to an nth washing assembly. The mth washing assembly includes an mth washing tower and an mth driving structure. The mth driving structure connects the mth inlet of the mth washing tower and the (m - 1)th washing tower, and the mth driving structure is configured to drive the gas in the (m - 1)th washing tower to flow into the mth washing tower for washing. Here, n≥2 and is a positive integer, 2≤m≤n, and m is a positive integer. Thus, the hydrogen fluoride gas can be washed multiple times by multiple washing assemblies to improve the recovery efficiency of the hydrogen fluoride gas.

[0051] For example, m is set to 2, and m can also be 3, 4, or more than 4. For the convenience of description, the present invention provides the following embodiments: Embodiment 1 m = 2, and the structure of the mth washing assembly is the same as that of the first washing assembly 50: The first washing assembly 50 includes a first washing tower 51, a first spraying structure 52, a first driving member 53, and a second driving member 54. The first spraying structure 52 is disposed in the first washing tower 51. The first driving member 53 connects the first washing tower 51 and the first spraying structure 52, and drives the washing medium in the first washing tower 51 to flow towards the first spraying structure 52. The first spraying structure 52 is configured to spray the gas in the first washing tower 51. The second driving member 54 connects the first washing tower 51 and drives the washing medium in the first washing tower 51 to flow back to the decomposition tower for recycling.

[0052] The second washing assembly 60 includes a second washing tower, a second spraying structure, a third driving member, and a fourth driving member. The second spraying structure is disposed in the second washing tower. The third driving member connects the second washing tower and the second spraying structure, and drives the washing medium in the second washing tower to flow towards the second spraying structure. The second spraying structure is configured to spray the gas in the second washing tower. The fourth driving member connects the second washing tower and drives the washing medium in the second washing tower to flow back to the decomposition tower for recycling.

[0053] Among them, the first washing tower 51 has a first inlet 511 and a second exhaust port 514. The first inlet 511 is connected to the first exhaust port 13 of the flash tank 10. The second washing tower has a second inlet and a third exhaust port. The second inlet is connected to the second exhaust port 514 of the first washing tower 51. A second driving structure is connected between the second inlet and the second exhaust port 514. A negative pressure generator 40 is connected between the first inlet 511 and the first exhaust port 13. The negative pressure generator 40 can generate a negative pressure in the flash tank 10 to reduce the evaporation temperature of the fluorosulfuric acid. Moreover, the hydrogen fluoride gas discharged from the flash tank 10 can be washed by the first washing tower 51 and the second washing tower, greatly improving the recovery and utilization of the hydrogen fluoride gas.

[0054] The negative pressure generator 40 may include an air flow driving member (such as a vacuum pump, etc.), and drive the gas in the flash evaporation tank 10 to flow into the first scrubbing tower 51 through the air flow driving member to generate negative pressure in the flash evaporation tank 10; alternatively, the negative pressure generator 40 may include a Venturi ejector 41 and a medium driving member 42, and make the scrubbing medium flow through the Venturi ejector 41 quickly through the medium driving member 42 to generate negative pressure in the flash evaporation tank 10 and pre-scrub the hydrogen fluoride gas to improve the recovery effect of the hydrogen fluoride gas.

[0055] Example 2 m = 2, the structure of the m-th scrubbing assembly is the same as that of the first scrubbing assembly 50, and the structure of the m-th driving structure is the same as that of the negative pressure generator 40: The first scrubbing assembly 50 includes a first scrubbing tower 51, a first spraying structure 52, a first driving member 53 and a second driving member 54. The first spraying structure 52 is arranged in the first scrubbing tower 51. The first driving member 53 is connected to the first scrubbing tower 51 and the first spraying structure 52, and drives the scrubbing medium in the first scrubbing tower 51 to flow towards the first spraying structure 52. The first spraying structure 52 is used for spraying the gas in the first scrubbing tower 51. The second driving member 54 is connected to the first scrubbing tower 51 and drives the scrubbing medium in the first scrubbing tower 51 to flow back to the decomposition tower for recycling.

[0056] The second scrubbing assembly 60 includes a second scrubbing tower, a second spraying structure, a third driving member and a fourth driving member. The second spraying structure is arranged in the second scrubbing tower. The third driving member is connected to the second scrubbing tower and the second spraying structure, and drives the scrubbing medium in the second scrubbing tower to flow towards the second spraying structure. The second spraying structure is used for spraying the gas in the second scrubbing tower. The fourth driving member is connected to the second scrubbing tower and drives the scrubbing medium in the second scrubbing tower to flow back to the decomposition tower for recycling.

[0057] Wherein, the first scrubbing tower 51 has a first inlet 511 and a second exhaust port 514. The first inlet 511 is connected to the first exhaust port 13 of the flash evaporation tank 10. The second scrubbing tower has a second inlet and a third exhaust port. The second inlet is connected to the second exhaust port 514 of the first scrubbing tower 51; and a first negative pressure generator (i.e., the negative pressure generator 40 mentioned above) is connected between the first inlet 511 and the first exhaust port 13, and a second negative pressure generator is connected between the second inlet and the second exhaust port 514. Negative pressure can be generated in the flash evaporation tank 10 through the first negative pressure generator and the second negative pressure generator to reduce the evaporation temperature of the fluorosulfuric acid, and the hydrogen fluoride gas discharged from the flash evaporation tank 10 can be scrubbed by the first scrubbing tower 51 and the second scrubbing tower, greatly improving the recovery and utilization of the hydrogen fluoride gas.

[0058] Moreover, the first negative pressure generator may include a first air flow driving member (such as a vacuum pump, etc.), and the air flow driving member is used to drive the gas in the flash evaporation tank 10 to flow into the first scrubbing tower 51, so as to generate a negative pressure in the flash evaporation tank 10. Similarly, the second negative pressure generator may include a second air flow driving member (such as a vacuum pump, etc.), which will not be elaborated here.

[0059] Alternatively, the first negative pressure generator may include a first Venturi ejector (the Venturi ejector 41 described above) and a first medium driving member (the medium driving member 42 described above). The first medium driving member is used to make the scrubbing medium flow through the first Venturi ejector quickly, so as to generate a negative pressure in the flash evaporation tank 10 and pre-scrub the hydrogen fluoride gas, improving the recovery effect of the hydrogen fluoride gas. Among them, the low-pressure inlet 412 and the mixing outlet 413 of the first Venturi ejector are respectively connected to the first scrubbing tower 51, and the high-pressure inlet 411 of the first Venturi ejector is connected to the flash evaporation tank 10.

[0060] Similarly, the second negative pressure generator may include a second Venturi ejector and a second medium driving member. The second medium driving member is used to make the scrubbing medium flow through the second Venturi ejector quickly, so as to generate a negative pressure in the flash evaporation tank 10 and pre-scrub the hydrogen fluoride gas, improving the recovery effect of the hydrogen fluoride gas. Among them, the low-pressure inlet 412 and the mixing outlet 413 of the second Venturi ejector are respectively connected to the second scrubbing tower, and the height inlet of the second Venturi ejector is connected to the second exhaust port 514 of the first scrubbing tower 51.

[0061] In some embodiments of the present invention, the heater 20 is a block-hole type silicon carbide heat exchanger. It can be understood that, compared with the tube row type heater 20, the block-hole type heater 20 has higher structural strength, can withstand greater impacts, and improves the working stability of the hydrogen fluoride recovery device 100. Moreover, the inner lining of the heater 20 can be made of silicon carbide material, so that the heater 20 can have good corrosion resistance and high temperature resistance, which is convenient for better heating of the fluorosulfuric acid.

[0062] It should be understood that the sulfuric acid decomposition method is a commonly used process for producing anhydrous hydrogen fluoride. Fluorosilicic acid is thermally decomposed into hydrogen fluoride and silicon tetrafluoride in the decomposition tower. Most of the hydrogen fluoride dissolves in sulfuric acid in the decomposition tower, and hydrogen fluoride is recovered through the processes of evaporating fluorosulfuric acid and hydrogen fluoride scrubbing. In the industry of evaporating fluorosulfuric acid, falling film evaporation or atmospheric pressure flash evaporation processes are mostly used. The operating temperature of this process is relatively high, and it is necessary to reach 170 °C to recover 90% of the hydrogen fluoride. Under this condition, it is extremely difficult for the equipment of the evaporation system to operate safely and reliably for a long time. At the same time, when scrubbing the evaporated hydrogen fluoride, multi-stage packed tower series scrubbing is mostly used in the industry, and the process is relatively complex, and the equipment investment is relatively large.

[0063] Therefore, the hydrogen fluoride recovery device 100 according to the embodiment of the present invention is involved in the processes of fluorosulfuric acid evaporation and hydrogen fluoride washing in the process of producing anhydrous hydrogen fluoride from fluosilicic acid. The device includes a heater 20, a flash tank 10, a forced circulation pump (i.e., a circulation driving member 30), a Venturi ejector 41, an ejector circulation pump (i.e., a medium driving member 42), a washing tower, and a washing tower circulation pump (i.e., a first driving member 53).

[0064] Among them, the heater 20 uses a block-hole type silicon carbide heat exchanger and is heated by 0.5 MPa steam to heat the temperature of the fluorosulfuric acid to 140 °C.

[0065] The flash tank 10 adopts a carbon steel molded PFA manufacturing process, with an internal pressure P' of -10 KPa and an internal temperature T of 140 °C, where the fluorosulfuric acid undergoes flash evaporation.

[0066] The forced circulation pump uses a PFA (Polyfluoroalkoxy, soluble polytetrafluoroethylene)-lined high-temperature resistant magnetic pump to continuously circulate the fluorosulfuric acid between the heater 20 and the flash tank 10.

[0067] The Venturi ejector adopts a carbon steel molded PFA manufacturing process. While creating a negative pressure in the flash tank 10, it mixes the evaporated hydrogen fluoride and sulfuric acid and enters them into the washing tower. The main structure of the Venturi tube includes a nozzle, a suction chamber, a mixing chamber, and a diffuser chamber. Among them, the nozzle is made of non-pressure sintered silicon carbide material, and other materials are made by the carbon steel film pressing PFA process. The sulfuric acid coming out of the ejector circulation pump is ejected from the nozzle, with a pressure reaching 0.4 MPa - 0.5 MPa and a temperature of 140 °C. Under the injection of high-speed sulfuric acid, a vacuum is formed in the suction chamber, and the negative pressure reaches -0.08 MPA. The HF (hydrogen fluoride) evaporated from the flash tank 10 is sucked into the suction chamber of the Venturi tube through the negative pressure. Then, HF enters the mixing chamber together with the injected sulfuric acid, and HF and sulfuric acid are fully mixed and washed in the mixing chamber to achieve the function of preliminary washing. After mixing, HF and sulfuric acid enter the diffuser chamber, with the pressure basically maintained at 0.4 MPa - 0.5 MPa and the temperature at 140 °C, and finally enter the washing tower.

[0068] The ejector circulation pump and the washing tower circulation pump use PFA-lined high-temperature resistant magnetic pumps, with the circulating medium being 98% sulfuric acid and the temperature being 140 °C, and they circulate inside the ejector and the washing tower respectively.

[0069] The washing tower adopts a carbon steel molded PFA manufacturing process, with a single packing tower double-spray structure. The packing is Pall rings, and the packing material is PTFE (filled polytetrafluoroethylene resin). The hydrogen fluoride after being mixed and washed by the Venturi ejector enters from the bottom of the washing tower for further spray washing.

[0070] Therefore, the hydrogen fluoride recovery device 100 according to the embodiment of the present invention can reduce the evaporation temperature of the fluorosulfuric acid by forming a vacuum through Venturi tube injection, improving the safety and stability of the system; in addition, through Venturi tube injection, HF is preliminarily mixed and washed, reducing the load on the scrubbing tower and the number of scrubbing towers.

[0071] In the description of the present invention, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0072] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "connected to", "fixed" and other terms should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0073] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "under" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0074] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0075] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A hydrogen fluoride recovery device, characterized in that: include: A flash tank, wherein the flash tank is provided with a first liquid discharge port, a liquid return port and a first exhaust port; a heater, the heater being connected to the first liquid discharge port and the liquid return port and being used for heating the medium flowing through the heater; a circulation driving member, the circulation driving member being connected in series with the heater and used for driving the medium in the flash tank to flow toward the heater; a negative pressure generator, the negative pressure generator being connected to the first exhaust port and used to extract gas from the flash tank to create a negative pressure in the flash tank; The first washing component comprises a first washing tower, the first washing tower is provided with a first inlet, the first inlet is connected to the negative pressure generator, and the first washing tower is used for washing the gas discharged from the negative pressure generator.

2. The hydrogen fluoride recovery device according to claim 1, characterized in that: The negative pressure generator is configured to produce a pressure P' in the flash tank that satisfies: -0.06MPa≤P'≤-0.01MPa; and / or, The negative pressure generator is configured such that the working pressure P of the negative pressure zone thereof and the pressure P' created in the flash tank satisfy the following: P≤2×P'.

3. The hydrogen fluoride recovery device according to claim 1, characterized in that: The first washing tower also has a second liquid discharge port, The negative pressure generator comprises a venturi ejector and a medium driving member, wherein the venturi ejector has a high pressure inlet, a low pressure inlet and a mixed outlet, wherein the low pressure inlet is connected to the first exhaust port, and the mixed outlet is connected to the first inlet. The high-pressure inlet is connected to the second liquid discharge port, and the medium driving member is connected in series between the second liquid discharge port and the high-pressure inlet and is used to drive the washing medium in the first washing tower to flow toward the high-pressure inlet; Alternatively, the hydrogen fluoride recovery device further comprises a liquid storage tank, the liquid storage tank is used to store washing medium, the high-pressure inlet is connected to the liquid storage tank, and the medium driving member is connected in series between the liquid storage tank and the high-pressure inlet and is used to drive the washing medium in the liquid storage tank to flow toward the high-pressure inlet.

4. The hydrogen fluoride recovery device according to claim 1, characterized in that: The first washing tower further comprises a third liquid discharge port and a second exhaust port, and the first washing assembly further comprises: A first spray structure and a first driving member, wherein the first driving member is connected between the third liquid discharge port and the first spray structure and is used to drive the washing medium in the first washing tower to flow toward the first spray structure, and the first spray structure is arranged in the first washing tower and is used to spray the gas flowing toward the second exhaust port.

5. The hydrogen fluoride recovery device according to claim 4, characterized in that: The first washing tower includes a first tower section and a second tower section, the first tower section is arranged on the upper side of the second tower section, and the cross-sectional area of ​​the first tower section is smaller than the cross-sectional area of ​​the second tower section, the second exhaust port is formed at the top of the first tower section, the first spray structure is arranged in the first tower section and is located below the second exhaust port, the first spray structure includes a plurality of spray units spaced apart from top to bottom, and each of the spray units includes at least one spiral nozzle.

6. The hydrogen fluoride recovery device according to claim 1, characterized in that: The first washing component also includes: A second driving member, the inlet of the second driving member is connected to the first washing tower, and the outlet of the second driving member is suitable for connecting to a decomposition tower for decomposing fluorosilicic acid, so that the second driving member is used to drive the washing medium in the first washing tower to flow to the decomposition tower.

7. The hydrogen fluoride recovery device according to claim 1, characterized in that: The negative pressure generator includes a gas driving member, which is connected to the first inlet and is used to drive the gas in the flash tank to be discharged toward the first washing tower.

8. The hydrogen fluoride recovery device according to any one of claims 1 to 7, characterized in that: The hydrogen fluoride recovery device also includes: The second washing assembly to the nth washing assembly, the mth washing assembly includes an mth washing tower and an mth driving structure, the mth driving structure is connected to the mth inlet of the mth washing tower and the (m-1)th washing tower, and is used to drive the gas in the (m-1)th washing tower to be discharged to the mth washing tower for washing, n≥2 and is a positive integer, 2≤m≤n, and m is a positive integer.

9. The hydrogen fluoride recovery device according to claim 8, characterized in that: The structure of the mth washing assembly is the same as that of the first washing assembly; And / or, the structure of the mth driving structure is the same as the structure of the negative pressure generator.

10. The hydrogen fluoride recovery device according to claim 1, characterized in that: The heater is configured as a block hole type silicon carbide heat exchanger.

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