Electronic-grade hydrofluoric acid processing system

Abstract

The invention relates to the technical field of hydrofluoric acid processing, in particular to an electronic-grade hydrofluoric acid processing system which comprises a raw material tank for storing liquid hydrogen fluoride, a dilute hydrofluoric acid tank for storing dilute hydrofluoric acid, a pure water tank for storing pure water and a finished product tank for storing finished hydrofluoric acid. A heat exchange module for heating liquid hydrogen fluoride into gaseous hydrogen fluoride is mounted at the output end of the raw material tank through a pipeline, a purification tower for removing impurities in the gaseous hydrogen fluoride is mounted at the gas output end of the heat exchange module through a pipeline, and a gas storage tank is mounted at the gas outlet end of the purification tower through a pipeline; an absorption tower is mounted at the output end of the gas storage tank through a pipeline; an absorption kettle is mounted at the liquid outlet end of the absorption tower; after the hydrogen fluoride liquid is gasified, impurities in gaseous hydrogen fluoride are removed to obtain high-purity gaseous hydrogen fluoride, and then hydrofluoric acid with the concentration gradually increased is generated in combination with pure water until the electronic-grade hydrofluoric acid conforming to process indexes is obtained.

Description

Technical Field

[0001] This invention relates to the field of hydrofluoric acid processing technology, and more specifically to an electronic-grade hydrofluoric acid processing system. Background Technology

[0002] Currently, the industry uses methods such as the fluorite process and the fluorosilicic acid byproduct process from phosphate fertilizer production to produce anhydrous hydrogen fluoride. Impurities from upstream raw materials, such as arsenic, sulfur, and iron, severely affect the quality of anhydrous hydrogen fluoride. Anhydrous hydrogen fluoride requires controlled arsenic content <5 ppm. Hydrogen fluoride is a gas that is highly soluble in water and miscible with water in any proportion. When hydrogen fluoride gas comes into contact with water, it dissolves rapidly and undergoes a hydration reaction to produce hydrofluoric acid. This process is strongly exothermic and significantly increases the solution temperature. According to GB / T 31369-2015, electronic-grade hydrofluoric acid is a colorless, transparent aqueous solution of hydrogen fluoride with a pungent odor. It is corrosive and highly toxic, and the required process parameters are: HF ≥ 40-55%, H₂SiF₆ ≤ 0.05%, SO₂ ≤ 0.03%, H₂SO₄ ≤ 0.05%.

[0003] The production principle is as follows: AHF (anhydrous hydrogen fluoride) delivered from the storage tank has a boiling point of 19.5℃. It is transported through pipelines to the distillation equipment for vaporization, and then introduced into the absorption tower. Using the principle of multiple condensation, the AHF gas is absorbed by pure water through water spray to form hydrofluoric acid. The production of high-purity electronic-grade hydrofluoric acid requires multiple distillation and ultrafiltration technologies.

[0004] However, this type of electronic-grade hydrofluoric acid requires high-purity anhydrous hydrogen fluoride, and the content of internal impurities must be extremely low to the point that no treatment is needed. In addition, additional distillation equipment is required, so the overall cost needs to be reduced.

[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to design an electronic-grade hydrofluoric acid processing system that can reduce the quality requirements of liquid hydrogen fluoride, remove impurities from liquid hydrogen fluoride, and eliminate the need for distillation equipment, thereby overcoming the aforementioned shortcomings in the technology.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an electronic-grade hydrofluoric acid processing system, comprising a raw material tank for storing liquid hydrogen fluoride, a dilute hydrofluoric acid tank for storing dilute hydrofluoric acid, a pure water tank for storing pure water, and a finished product tank for storing finished hydrofluoric acid. The input end of the finished product tank is connected to an ultrafiltration device via a pipeline. The output end of the raw material tank is connected to a heat exchange module via a pipeline to heat the liquid hydrogen fluoride into gaseous hydrogen fluoride. The gas output end of the heat exchange module is connected to a purification tower via a pipeline to remove impurities from the gaseous hydrogen fluoride. The gas outlet end of the purification tower is connected to a gas storage device via a pipeline. The tank and the gas storage tank have an absorption tower installed at their output end via a pipeline. An absorption vessel is installed at the liquid outlet end of the absorption tower. An absorption pump is installed at the liquid outlet end of the absorption vessel via a pipeline. The input end of the ultrafiltration equipment and the hot liquid input end of the heat exchange module are both connected to the output end of the absorption pump via pipelines. The input ends of the spray module of the absorption tower and the dilute hydrofluoric acid tank are both connected to the hot liquid output end of the heat exchange module via pipelines. The output end of the dilute hydrofluoric acid tank and the input end of the spray module of the purification tower are connected via pipelines. The output end of the pure water tank is connected to another spray module of the absorption tower via a pipeline.

[0008] Preferably, the heat exchange module includes an inner liner, a middle shell, and an outer shell. A cold liquid pipe is fixedly installed on one side of the inner liner, penetrating the middle shell and the outer shell and fixedly connected thereto. A gas output end is fixedly installed on the top of the inner liner, penetrating the middle shell and the outer shell and fixedly connected thereto. A hot liquid input end is fixedly installed on one side of the outer shell, and a hot liquid output end is fixedly installed on the other side of the outer shell. A liquid inlet end is fixedly installed on one side of the middle shell, penetrating the outer shell and fixedly connected thereto. A liquid outlet end is installed on the other side of the middle shell, penetrating the outer shell and fixedly connected thereto. The middle shell is filled with a heat-conducting liquid.

[0009] Preferably, a cooler is also installed on the pipe installed on the hydrothermal outlet.

[0010] Preferably, a residual liquid tank is installed at the outlet end of the purification tower via a pipeline, a residual liquid pump is installed at the output end of the residual liquid tank via a pipeline, and an industrial hydrofluoric acid tank is installed at the output end of the residual liquid pump via a pipeline.

[0011] Preferably, the concentration of liquid dilute hydrofluoric acid in the dilute hydrofluoric acid tank is 10%-30%.

[0012] Preferably, the concentration of liquid hydrofluoric acid in the finished product tank is 40%-55%.

[0013] Preferably, the temperature of the heat-conducting fluid inside the middle shell is 30℃-50℃.

[0014] Preferably, the temperature inside the absorption vessel is not higher than 50°C.

[0015] Preferably, the exhaust end of the absorption tower is equipped with a tail gas treatment tower via a pipeline.

[0016] The technical effects and advantages provided by the present invention in the above technical solution are as follows:

[0017] 1. This invention involves vaporizing liquid hydrogen fluoride, removing impurities from the gaseous hydrogen fluoride to obtain high-purity gaseous hydrogen fluoride, and then combining it with pure water to generate hydrofluoric acid with a gradually increasing concentration until electronic-grade hydrofluoric acid that meets the process specifications is obtained.

[0018] 2. This invention utilizes the heat generated in the subsequent process of combining gaseous hydrogen fluoride with pure water to produce hydrofluoric acid to heat liquid hydrogen fluoride into gaseous hydrogen fluoride in the preceding process via a heat exchange module. This, combined with a purification tower to remove impurities, yields high-purity gaseous hydrogen fluoride without the need for distillation equipment and reduces the cooling pressure of the cooler.

[0019] 3. At the same time, when high-purity gaseous hydrogen fluoride is dissolved in pure water to generate hydrofluoric acid with gradually increasing concentration, a portion of the produced dilute hydrofluoric acid is pumped into a dilute hydrofluoric acid tank to remove impurities in the gaseous hydrogen fluoride in the purification tower, and the concentration of the hydrofluoric acid not pumped into the dilute hydrofluoric acid tank is increased to electronic grade hydrofluoric acid.

[0020] 4. The residual liquid obtained by treating impurities in gaseous hydrogen fluoride with dilute hydrofluoric acid in the purification tower of the present invention can also be pumped into the residual liquid tank for the production of industrial-grade hydrofluoric acid. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0022] Figure 1 This is a system flowchart of the present invention;

[0023] Figure 2 This is a simplified schematic diagram of the heat exchange device of the present invention;

[0024] Figure 3 This is a prior art flowchart of the present invention;

[0025] Figure 4 This is a schematic diagram of the hydrofluoric acid circulation in the absorption tower of the present invention.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1. Raw material tank; 2. Dilute hydrofluoric acid tank; 3. Pure water tank; 4. Finished product tank; 5. Ultrafiltration equipment; 6. Heat exchange module; 601. Inner liner; 602. Middle shell; 603. Outer shell; 604. Cold liquid pipe; 605. Gas outlet; 606. Hot liquid inlet; 607. Hot liquid outlet; 608. Liquid inlet; 609. Liquid outlet; 7. Purification tower; 8. Gas storage tank; 9. Absorption tower; 10. Absorption vessel; 11. Absorption pump; 12. Cooler; 13. Residual liquid tank; 14. Residual liquid pump; 15. Industrial hydrofluoric acid tank; 16. Tail gas treatment tower. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0030] This invention provides, for example Figure 1-2The illustrated electronic-grade hydrofluoric acid processing system includes a housing 603, a middle housing 602 installed inside the housing 603, and a hollow inner liner 601 installed inside the middle housing 602. A cooling liquid pipe 604 is installed on one side of the inner liner 601, penetrating the middle housing 602 and the housing 603 and fixedly connected thereto. A gas output terminal 605 is installed on the top of the inner liner 601, penetrating the middle housing 602 and the housing 603 and fixedly connected thereto. A liquid inlet 608 is installed on one side of the middle housing 602, penetrating the housing 603 and fixedly connected thereto. Simultaneously, a liquid outlet 609 is installed on the other side of the middle housing 602, penetrating the housing 603 and fixedly connected thereto. A cooling liquid pipe 604 is fixedly installed on one side of the housing 603. The device includes a hydrothermal inlet 606, a hydrothermal outlet 607 fixedly installed on the other side of the outer casing 603, a raw material tank 1 for storing liquid hydrogen fluoride, a pure water tank 3 for storing pure water, a dilute hydrofluoric acid tank 2 for storing dilute hydrofluoric acid, a finished product tank 4 for storing finished hydrofluoric acid, an ultrafiltration device 5 for refining hydrofluoric acid liquid, a purification tower 7 for removing impurities entrained in gaseous hydrogen fluoride, a gas storage tank 8 for storing purified gaseous hydrogen fluoride, an absorption tower 9 for converting gaseous hydrogen fluoride into hydrofluoric acid, an absorption vessel 10 installed at the liquid outlet 609 of the absorption tower 9, and an absorption pump 11 for pumping hydrofluoric acid from the absorption vessel 10 into the hydrothermal inlet 606 and the ultrafiltration device 5. The impurities carried by the gaseous hydrogen fluoride include sulfur dioxide, sulfuric acid mist, and moisture. Both purification tower 7 and absorption tower 9 are equipped with spray modules. The output end of raw material tank 1 is connected to the cold liquid pipe 604 via a pipeline. The gas output end 605 is connected to the input end of purification tower 7 via a pipeline. The gas outlet end of purification tower 7 is connected to the gas storage tank 8 via a pipeline. The output end of gas storage tank 8 is connected to the input end of absorption tower 9 via a pipeline. The liquid outlet end 609 of absorption vessel 10 is connected to the input end of absorption pump 11 via a pipeline. The input end of ultrafiltration equipment 5 and the hot liquid input end 606 are both connected to the output end of absorption pump 11 via a pipeline. The input end of the dilute hydrofluoric acid tank 2 and the spray module on the absorption tower 9 are both connected to the hot liquid output end 607 via pipes. The output end of the dilute hydrofluoric acid tank 2 is connected to the spray module on the purification tower 7 via pipes. The output end of the pure water tank 3 is connected to another spray module on the absorption tower 9 via pipes. Valves are installed on the pipes as needed. The outer shell 603, the middle shell 602, the inner liner 601, the cold liquid pipe 604, the gas output end 605, the liquid inlet end 608, the liquid outlet end 609, the hot liquid input end 606, and the hot liquid output end 607 constitute the heat exchange module 6 for heating liquid hydrogen fluoride into gaseous hydrogen fluoride.

[0031] When using:

[0032] S1. Pure water in pure water tank 3 is introduced into absorption tower 9 through spray module, and then gradually flows into absorption vessel 10 until the upper limit of liquid level reaches the specified amount. Then the introduction of pure water in pure water tank 3 is closed. Then the absorption pump 11 is started to continuously pump pure water in absorption vessel 10 into outer shell 603, and then sprayed into absorption tower 9 through pipeline and spray module to form a cycle.

[0033] S2. Then, slightly open the valve of the gas storage tank 8 and gradually introduce the gaseous hydrogen fluoride stored in the gas storage tank 8 into the absorption tower 9. After the gaseous hydrogen fluoride is introduced into the absorption tower 9, it will come into contact with the circulating pure water sprayed downward in the spray module, and a physical reaction will occur in which hydrogen fluoride dissolves in pure water, releasing heat to form a low concentration of hydrofluoric acid. As the low concentration of hydrofluoric acid is continuously circulated and sprayed to absorb the contacting gaseous hydrogen fluoride, the liquid concentration of hydrofluoric acid in the absorption vessel 10 will gradually increase. When it increases to a predetermined value, such as 10%-30%, stop injecting the gaseous hydrofluoric acid in the gas storage tank 8 into the absorption tower 9. Instead, use the absorption pump 11 to pump the low concentration of dilute hydrofluoric acid into the dilute hydrofluoric acid tank 2 until the dilute hydrofluoric acid liquid level in the absorption vessel 10 reaches the designated position, and then stop pumping dilute hydrofluoric acid into the dilute hydrofluoric acid tank 2.

[0034] S3. Continue to open the gas storage tank 8 to introduce gaseous hydrogen fluoride into the absorption tower 9, and use the absorption pump 11 to continue circulating and spraying dilute hydrofluoric acid until the concentration of dilute hydrofluoric acid reaches the concentration of the finished hydrofluoric acid, such as 40%-55%. At this time, close the pipeline from the gas storage tank 8 to the absorption tower 9 to stop the injection of gaseous hydrogen fluoride. Then, pump the hydrofluoric acid of the required concentration into the ultrafiltration equipment 5 through the absorption pump 11. After being purified by the ultrafiltration equipment 5, inject it into the finished product tank 4.

[0035] S4. During the production of dilute hydrofluoric acid and finished hydrofluoric acid in steps S1 and S2, the gaseous hydrogen fluoride undergoes an exothermic physical reaction upon contact with pure water and as its concentration increases. The heated liquid hydrofluoric acid enters the outer shell 603 through the hot liquid inlet 606 and exits through the hot liquid outlet 607. During this process, heat is transferred to the middle shell 602 via heat transfer. A heat-conducting liquid can be introduced into the middle shell 602 through the liquid inlet 608 and liquid outlet 609, causing the heat-conducting liquid to absorb the transferred heat and heat up to 30℃-50℃. Meanwhile, when the raw material tank 1 introduces liquid hydrogen fluoride into the inner liner 601 through the cold liquid pipe 604, it absorbs heat and vaporizes into gaseous hydrogen fluoride. This gaseous hydrogen fluoride contains impurities and exits through the gas outlet 607. 05. The dilute hydrofluoric acid in tank 2 is sprayed onto the gaseous hydrogen fluoride and impurities through the spray module in purification tower 7. SO2 has a very high solubility in water and dilute acid, which is dozens of times that of gaseous hydrogen fluoride. When the mixed gas containing hydrogen fluoride and SO2 comes into countercurrent contact with low-temperature dilute hydrofluoric acid, SO2 will preferentially and in large quantities dissolve into the liquid phase. Sulfuric acid mist is essentially liquid particles, which are more easily captured and dissolved by low-temperature dilute hydrofluoric acid at low temperatures through inertial collision, condensation and other mechanisms. A small amount of gaseous water will be absorbed by the hydrofluoric acid solution. Therefore, a small amount of gaseous hydrogen fluoride and impurities will be incorporated into the liquid dilute hydrofluoric acid and then discharged from the drain end of purification tower 7. Most of the gaseous hydrogen fluoride is introduced into the gas storage tank 8 through the pipeline from the gas outlet end of purification tower 7.

[0036] Furthermore, a cooler 12 is installed on the pipe installed on the hot liquid outlet 607 to further cool the liquid hydrofluoric acid discharged from the outer shell 603, so that the dilute hydrofluoric acid stored in the dilute hydrofluoric acid tank 2 is a low-temperature liquid, which also further reduces the temperature inside the reactor, so that the temperature inside the reactor does not exceed a specified value, such as 50°C. At the discharge end of the purification tower 7, a residual liquid tank 13 is installed through a pipe to store the liquid dilute hydrofluoric acid that absorbs impurities and gaseous hydrogen fluoride. The output end of the residual liquid tank 13 is connected to a residual liquid pump 14 through a pipe, and the output end of the residual liquid pump 14 is connected to an industrial hydrofluoric acid tank 15 through a pipe. At the same time, the exhaust end of the absorption tower 9 is connected to a tail gas treatment tower 16 through a pipe to treat the gaseous hydrogen fluoride that has not been completely integrated into the hydrofluoric acid in the absorption tower 9.

[0037] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible (e.g., changes in the size, dimensions, structure, shape and proportion of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), installation arrangements, use of materials, color, orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application.

Claims

1. An electronic-grade hydrofluoric acid processing system, characterized in that: The system includes a raw material tank (1) for storing liquid hydrogen fluoride, a dilute hydrofluoric acid tank (2) for storing dilute hydrofluoric acid, a pure water tank (3) for storing pure water, and a finished product tank (4) for storing finished hydrofluoric acid. The input end of the finished product tank (4) is connected to an ultrafiltration device (5) via a pipeline. The output end of the raw material tank (1) is connected to a heat exchange module (6) for heating liquid hydrogen fluoride into gaseous hydrogen fluoride via a pipeline. The gas output end (605) of the heat exchange module (6) is connected to a purification tower (7) for removing impurities from gaseous hydrogen fluoride via a pipeline. The gas outlet end of the purification tower (7) is connected to a gas storage tank (8) via a pipeline. The output end of the gas storage tank (8) is connected to an absorption tower (9) via a pipeline. An absorption vessel (10) is installed at the liquid outlet (609). An absorption pump (11) is installed at the liquid outlet (609) of the absorption vessel (10) through a pipeline. The input end of the ultrafiltration device (5) and the hot liquid input end (606) of the heat exchange module (6) are both connected to the output end of the absorption pump (11) through pipelines. The input ends of the spray module of the absorption tower (9) and the dilute hydrofluoric acid tank (2) are both connected to the hot liquid output end (607) of the heat exchange module (6) through pipelines. The output end of the dilute hydrofluoric acid tank (2) and the input end of the spray module of the purification tower (7) are connected through pipelines. The output end of the pure water tank (3) is connected to another spray module of the absorption tower (9) through a pipeline.

2. The electronic-grade hydrofluoric acid processing system according to claim 1, characterized in that: The heat exchange module (6) includes an inner liner (601), a middle shell (602), and an outer shell (603). A cold liquid pipe (604) is fixedly installed on one side of the inner liner (601) and is fixedly connected to the middle shell (602) and the outer shell (603). A gas output end (605) is fixedly installed on the top of the inner liner (601) and is fixedly connected to the middle shell (602) and the outer shell (603). A hot liquid input end (606) is fixedly installed on one side of the outer shell (603), and a hot liquid output end (607) is fixedly installed on the other side of the outer shell (603). An inlet end (608) is fixedly installed on one side of the middle shell (602) and is fixedly connected to the outer shell (603). An outlet end (609) is installed on the other side of the middle shell (602) and is fixedly connected to the outer shell (603). The middle shell (602) is filled with a heat-conducting liquid.

3. The electronic-grade hydrofluoric acid processing system according to claim 2, characterized in that: A cooler (12) is also installed on the pipe installed on the hydrothermal outlet (607).

4. The electronic-grade hydrofluoric acid processing system according to claim 1, characterized in that: The purification tower (7) has a residual liquid tank (13) installed on the liquid outlet (609) via a pipe, a residual liquid pump (14) installed on the output end of the residual liquid tank (13) via a pipe, and an industrial hydrofluoric acid tank (15) installed on the output end of the residual liquid pump (14) via a pipe.

5. The electronic-grade hydrofluoric acid processing system according to claim 1, characterized in that: The concentration of liquid dilute hydrofluoric acid in the dilute hydrofluoric acid tank (2) is 10%-30%.

6. The electronic-grade hydrofluoric acid processing system according to claim 1, characterized in that: The concentration of liquid hydrofluoric acid in the finished product tank (4) is 40%-55%.

7. The electronic-grade hydrofluoric acid processing system according to claim 1, characterized in that: The temperature of the heat transfer fluid inside the middle shell (602) is 30℃-50℃.

8. The electronic-grade hydrofluoric acid processing system according to claim 1, characterized in that: The temperature inside the absorption vessel (10) is not higher than 50°C.

9. The electronic-grade hydrofluoric acid processing system according to claim 1, characterized in that: The exhaust end of the absorption tower (9) is equipped with a tail gas treatment tower (16) via a pipeline.

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