Coupling device for electronic-grade hydrofluoric acid and fluorine-nitrogen mixture

Abstract

This utility model relates to a coupling device for electronic-grade hydrofluoric acid and a fluorine-nitrogen mixture, characterized by comprising a raw material tank, an evaporator, a first heat exchanger, a filter, an electrolytic cell, a purifier, a second heat exchanger, and an intermediate tank connected in sequence. The branch outputs of the filter are connected in sequence to an absorption tower and a product tank. The evaporator, the first heat exchanger, the electrolytic cell, and the second heat exchanger are each wound with interconnected coils. This utility model device can reduce energy consumption in production, save steam and heat usage, and is beneficial for reducing the cost of producing the two products separately.

Description

Technical fields:

[0002] This utility model relates to a chemical process equipment, and more particularly to a coupling device for electronic-grade hydrofluoric acid and a fluorine-nitrogen mixture. Background technology:

[0004] Electronic-grade hydrofluoric acid is a core chemical in semiconductor manufacturing processes. It can be used to remove oxide layers and photoresist residues from silicon wafers, ensuring chip yield. It can also be used to clean the silicon wafer surface of solar cells and form a textured surface, improving light absorption efficiency.

[0005] The electronic-grade fluorine-nitrogen mixer is made of high-purity fluorine gas and high-purity nitrogen gas. It is mainly used in semiconductor etching and CVD chamber cleaning, and can also be used in the display panel field to etch ITO electrodes.

[0006] The current traditional process is as follows: electronic-grade hydrofluoric acid is formed by purifying AHF (anhydrous hydrogen fluoride) to a high purity level and then mixing it with high-purity water. Electronic-grade fluorine-nitrogen mixture is formed by electrolyzing AHF to obtain fluorine gas, which is then mixed with nitrogen gas to form the final fluorine-nitrogen mixture.

[0007] In the existing production process, the two processes are carried out separately, making it difficult to form an efficient industrial whole. Moreover, most fluorine and nitrogen gas producers produce fluorine and nitrogen gas by purchasing ordinary AHF, which contains a lot of impurities. During the subsequent electrolysis process, these impurities will participate in the electrolysis, forming impurities that are difficult to remove, making it difficult to achieve a high purity level, or requiring purification through distillation, which greatly increases the production cost.

[0008] In the production process of electronic-grade fluorine and nitrogen gas, the electrolysis process is an exothermic reaction, and the waste heat generated is difficult to reuse. Utility Model Content:

[0010] In view of the above-mentioned shortcomings of the prior art, the purpose of this utility model is to provide a coupling device for electronic grade hydrofluoric acid and fluorine-nitrogen mixture. This device can reduce energy consumption in production, save the use of steam and heat, and help save the cost of producing the two products separately.

[0011] The present invention relates to a coupling device for electronic-grade hydrofluoric acid and a fluorine-nitrogen mixture, characterized in that: it comprises a raw material tank, an evaporator, a first heat exchanger, a filter, an electrolytic cell, a purifier, a second heat exchanger, and an intermediate tank connected in sequence; the branch output end of the filter is connected in sequence to an absorption tower and a product tank; and the evaporator, the first heat exchanger, the electrolytic cell, and the second heat exchanger are respectively wound with coils that are interconnected in a circulating manner.

[0012] Preferably, a transfer pump is connected between the raw material tank and the evaporator. The upper inlet of the raw material tank is used to introduce AHF raw material, and the lower outlet of the raw material tank is connected to the inlet of the evaporator through the transfer pump.

[0013] Preferably, the inlet of the electrolyzer is connected to the first branch output of the filter, the first outlet of the electrolyzer is connected to the inlet of the purifier for purifying the fluorine gas generated by the electrolysis of the electrolyzer, and the second outlet of the electrolyzer is connected to the tail gas processor for tail gas treatment of the hydrogen gas generated by the electrolysis of the electrolyzer.

[0014] Preferably, the second branch output end of the filter is connected to the absorption tower so that the high-purity AHF filtered by the filter can be absorbed and mixed by pure water through the absorption tower.

[0015] Preferably, the evaporator described above is a graphite evaporator or a PFA rotary evaporator.

[0016] Preferably, the above-mentioned filter is a polytetrafluoroethylene (PTFE) spray-coated anti-corrosion filter, a high-temperature electrostatic coating anti-corrosion filter, or a steel-lined PTFE anti-corrosion bag filter.

[0017] Preferably, the electrolytic cell is a low-carbon steel cathode-protected electrolytic cell or a polytetrafluoroethylene (PTFE) electrolytic cell.

[0018] Preferably, the purifier described above is a cold trap purifier.

[0019] Preferably, the above-mentioned absorption tower is a sulfuric acid absorption tower and a spray absorption tower.

[0020] Preferably, the exhaust gas processor is a recycling device, a combustion treatment device, a catalytic treatment device, or an adsorption treatment device.

[0021] The working principle of this invention, a coupling device for electronic-grade hydrofluoric acid and a fluorine-nitrogen mixture, is as follows: AHF (anhydrous hydrogen fluoride) enters the raw material tank through the feed pipeline and is pumped to the evaporator, where the temperature is controlled at 20-30℃. The AHF is slowly evaporated in the evaporator, then condensed into a liquid through the first heat exchanger, and impurities are removed by a filter. After this process, high-purity AHF is obtained. After filtration, the mixture splits into two branches. The first branch goes to the electrolytic cell, where the high-purity AHF is electrolyzed to produce fluorine and hydrogen. The hydrogen is sent to the tail gas processor for tail gas treatment, while the fluorine is connected to the purifier. In the purifier, the fluorine is cooled to -196℃ by liquid nitrogen. After the purifier removes non-condensable gases, the purified fluorine enters the second heat exchanger, is heated to room temperature, and then discharged into the intermediate tank, where it is mixed with nitrogen before filling. The second branch of the filter enters the absorption tower for the preparation of hydrofluoric acid, where pure water is used to absorb and mix the AHF before it enters the product tank.

[0022] The evaporator, the first heat exchanger, the electrolytic cell, and the second heat exchanger are each equipped with interconnected coils. The electrolytic cell uses external coils to stabilize its temperature at 80-100℃, while the refrigerant flows through pipes to the second heat exchanger at the rear of the purifier. The refrigerant temperature inside the pipes is 80-90℃. By heating the second heat exchanger, the fluorine gas passing through the purifier's cold trap is heated to room temperature. At this point, the refrigerant outlet temperature of the second heat exchanger is 30-40℃, which can be led through pipes to the coils on the evaporator. This temperature is just right for the evaporator to heat the AHF. After heat exchange, the refrigerant temperature drops to about 10℃ and can be led to the first heat exchanger to cool the AHF vapor. At this point, the refrigerant temperature rises to 18-25℃ and continues to flow to the electrolytic cell, completing one cycle of thermal coupling.

[0023] This utility model relates to a coupling device for electronic-grade hydrofluoric acid and fluorine-nitrogen mixture. By thermally coupling the waste heat generated by electrolysis with the heat-using equipment or heat exchanger of the upstream process, it reduces energy consumption in production and saves steam and heat usage. At the same time, through the co-production process, it greatly improves the product quality of fluorine-nitrogen mixture and can control the production technology of hydrofluoric acid and fluorine-nitrogen mixture in real time, which greatly saves the cost of producing the two products separately. Attached image description:

[0025] Figure 1 This is a schematic diagram of the working principle of this utility model;

[0026] Figure 2 This is a partial working principle diagram of this utility model;

[0027] Figure 3 This is a partial working principle diagram of this utility model. Detailed implementation method:

[0029] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be pointed out that the following detailed description is exemplary and intended to provide further explanation of the present application; unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0030] The present invention relates to a coupling device for electronic-grade hydrofluoric acid and a fluorine-nitrogen mixture, comprising a raw material tank 1, an evaporator 2, a first heat exchanger 3, a filter 4, an electrolytic cell 5, a purifier 6, a second heat exchanger 7, and an intermediate tank 8 connected in sequence. The branch output end (i.e., the second branch) of the filter 4 is connected in sequence to an absorption tower 9 and a product tank 10. Coils 11, which are mutually circulated and connected, are wound around the evaporator 2, the first heat exchanger 3, the electrolytic cell 5, and the second heat exchanger 7. A refrigerant, which may be water, circulates in the coils 11.

[0031] AHF (anhydrous hydrogen fluoride) passes through the main pipelines of evaporator 2 and the first heat exchanger 3. The coils on evaporator 2 and the first heat exchanger 3 are not connected to their main pipelines; the main pipelines of electrolytic cell 5 and the second heat exchanger 7 are also not connected to the coils wound on them.

[0032] The raw material tank 1 is connected to the evaporator 2 by a transfer pump 12. The upper inlet of the raw material tank 1 is used to introduce AHF raw material, and the lower outlet of the raw material tank 1 is connected to the inlet of the evaporator 2 through the transfer pump 12.

[0033] The inlet of the electrolytic cell 5 is connected to the first branch output of the filter 4, the first outlet of the electrolytic cell 5 is connected to the inlet of the purifier 6, the purifier 6 is used to purify the fluorine gas generated by the electrolysis of the electrolytic cell, and the second outlet of the electrolytic cell is connected to the tail gas processor 13, the tail gas processor 13 is used to treat the tail gas of the hydrogen gas generated by the electrolysis of the electrolytic cell.

[0034] The second branch output of filter 4 is connected to the absorption tower 9, and the high-purity AHF filtered by the filter is absorbed and mixed by pure water through the absorption tower.

[0035] The evaporator can be a graphite evaporator or a PFA rotary evaporator. The graphite evaporator is made of high-quality graphite and has the characteristics of corrosion resistance, good thermal conductivity, high temperature resistance, safe and stable operation, simple structure and easy maintenance. The PFA rotary evaporator can be the RNKG-RE201 model produced by Nanjing Ruinike.

[0036] The filter can be a PTFE spray-coated anti-corrosion filter, a high-temperature electrostatic coating anti-corrosion filter, or a steel-lined PTFE anti-corrosion bag filter. Specifically, it can be the FC / FS series hydrofluoric acid filter from Nanjing Bolu Industrial Co., Ltd., or the RNKW-PTFEBSLD model PTFE Buchner funnel-type hydrofluoric acid resistant filter from Nanjing Ruinike.

[0037] The electrolytic cell can be a low-carbon steel cathode-protected electrolytic cell or a polytetrafluoroethylene (PTFE) electrolytic cell. The specific model can be the RNKS-F4FC PTFE electrolytic cell from Nanjing Ruinike Technology Development Co., Ltd.

[0038] The purifier is a cold trap purifier; the absorption towers are a sulfuric acid absorption tower and a spray absorption tower.

[0039] The exhaust gas processor 13 can be of various types, such as recycling equipment, combustion treatment equipment, catalytic treatment equipment, adsorption treatment equipment, etc. Recycling equipment includes hydrogen recovery systems using pressure swing adsorption (PSA) technology; combustion treatment equipment is a burner; catalytic treatment equipment includes catalytic combustion devices (using catalysts such as silver, copper, and iron to convert hydrogen into water vapor); adsorption treatment equipment includes activated carbon adsorption devices or chemical adsorption devices (using adsorbents such as sodium hydroxide to remove harmful gases).

[0040] The transfer pump can be a magnetic pump, a self-priming fluoroplastic pump, a shielded pump, or a submersible pump, etc.

[0041] The above-mentioned raw material tank 1, evaporator 2, first heat exchanger 3, filter 4, electrolytic cell 5, purifier 6, second heat exchanger 7, and intermediate tank 8 are all commercially available equipment. The above are just some examples, and their structure and working principle are not described in detail.

[0042] The working principle of this invention, a coupling device for electronic-grade hydrofluoric acid and a fluorine-nitrogen mixture, is as follows: AHF (anhydrous hydrogen fluoride) enters the raw material tank through the feed pipeline and is pumped to the evaporator, where the temperature is controlled at 20-30℃. The AHF is slowly evaporated in the evaporator, then condensed into a liquid through the first heat exchanger, and impurities are removed by a filter. After this process, high-purity AHF is obtained. After filtration, the mixture splits into two branches. The first branch goes to the electrolytic cell, where the high-purity AHF is electrolyzed to produce fluorine and hydrogen. The hydrogen is sent to the tail gas processor for tail gas treatment, while the fluorine is connected to the purifier. In the purifier, the fluorine is cooled to -196℃ by liquid nitrogen. After the purifier removes non-condensable gases, the purified fluorine enters the second heat exchanger, is heated to room temperature, and then discharged into the intermediate tank, where it is mixed with nitrogen before filling. The second branch of the filter enters the absorption tower for the preparation of hydrofluoric acid, where pure water is used to absorb and mix the AHF before it enters the product tank.

[0043] The evaporator, the first heat exchanger, the electrolytic cell, and the second heat exchanger are each equipped with interconnected coils. The electrolytic cell uses external coils to stabilize its temperature at 80-100℃, while the refrigerant flows through pipes to the second heat exchanger at the rear of the purifier. The refrigerant temperature inside the pipes is 80-90℃. By heating the second heat exchanger, the fluorine gas passing through the purifier's cold trap is heated to room temperature. At this point, the refrigerant outlet temperature of the second heat exchanger is 30-40℃, which can be led through pipes to the coils on the evaporator. This temperature is just right for the evaporator to heat the AHF. After heat exchange, the refrigerant temperature drops to about 10℃ and can be led to the first heat exchanger to cool the AHF vapor. At this point, the refrigerant temperature rises to 18-25℃ and continues to flow to the electrolytic cell, completing one cycle of thermal coupling.

[0044] This utility model relates to a coupling device for electronic-grade hydrofluoric acid and fluorine-nitrogen mixture. By thermally coupling the waste heat generated by electrolysis with the heat-using equipment or heat exchanger of the upstream process, it reduces energy consumption in production and saves steam and heat usage. At the same time, through the co-production process, it greatly improves the product quality of fluorine-nitrogen mixture and can control the production technology of hydrofluoric acid and fluorine-nitrogen mixture in real time, which greatly saves the cost of producing the two products separately.

[0045] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A coupling device for electronic grade hydrofluoric acid and fluorine-nitrogen gas mixture, characterized by: It includes a raw material tank, an evaporator, a first heat exchanger, a filter, an electrolytic cell, a purifier, a second heat exchanger, and an intermediate tank connected in sequence. The branch output end of the filter is connected in sequence to an absorption tower and a product tank. The evaporator, the first heat exchanger, the electrolytic cell, and the second heat exchanger are respectively equipped with coils that are interconnected and circulated with each other.

2. The apparatus of claim 1, wherein: A transfer pump is connected between the raw material tank and the evaporator. The upper inlet of the raw material tank is used to introduce AHF raw material, and the lower outlet of the raw material tank is connected to the inlet of the evaporator through the transfer pump.

3. The apparatus of claim 2, wherein: The inlet of the electrolytic cell is connected to the first branch output of the filter, the first outlet of the electrolytic cell is connected to the inlet of the purifier for purifying the fluorine gas generated by the electrolysis of the electrolytic cell, and the second outlet of the electrolytic cell is connected to the tail gas processor for tail gas treatment of the hydrogen gas generated by the electrolysis of the electrolytic cell.

4. The apparatus of claim 3, wherein: The second branch output of the filter is connected to the absorption tower so that the high-purity AHF filtered by the filter can be absorbed and mixed by pure water through the absorption tower.

5. The electronic grade hydrofluoric acid and fluorine-nitrogen gas coupling apparatus according to claim 1, 2, 3 or 4, characterized by: The evaporator is a graphite evaporator or a PFA rotary evaporator.

6. The electronic grade hydrofluoric acid and fluorine-nitrogen gas coupling apparatus according to claim 1, 2, 3 or 4, characterized by: The filter is a polytetrafluoroethylene (PTFE) sprayed anti-corrosion filter, a high-temperature electrostatic coating anti-corrosion filter, or a steel-lined PTFE anti-corrosion bag filter.

7. The electronic grade hydrofluoric acid and fluorine-nitrogen gas coupling apparatus according to claim 1, 2, 3 or 4, characterized by: The electrolytic cell is a low-carbon steel cathode-protected electrolytic cell or a polytetrafluoroethylene (PTFE) electrolytic cell.

8. The electronic grade hydrofluoric acid and fluorine-nitrogen gas coupling apparatus according to claim 1, 2, 3 or 4, characterized by: The purifier is a cold trap purifier.

9. The electronic grade hydrofluoric acid and fluorine-nitrogen gas coupling apparatus according to claim 1, 2, 3 or 4, characterized by: The absorption towers mentioned are sulfuric acid absorption towers and spray absorption towers.

10. The electronic grade hydrofluoric acid and fluorine-nitrogen gas coupling apparatus according to claim 3 or 4, characterized by: The exhaust gas processor is a recycling device, a combustion treatment device, a catalytic treatment device, or an adsorption treatment device.

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