Corrosive gas supply device

Abstract

A corrosive gas supply device of the present disclosure is able to supply a corrosive gas to a liquid supplied to the exterior or interior of a hollow fiber membrane, the device comprising: a gas supply module; a liquid supply mechanism for supplying a liquid to the gas supply module; and a corrosive gas supply mechanism for supplying the corrosive gas to the gas supply module. The gas supply module comprises a housing, and a plurality of the hollow fiber membranes which are composed mainly of polytetrafluoroethylene or modified polytetrafluoroethylene; the average outer diameter D2 in the hollow fiber membranes is 0.60 mm or less and the average inner diameter D1 is 0.36 mm or less. The water pressure resistance and internal burst pressure is 1.5 MPaG or higher. At least an inner peripheral surface of the housing is made of a corrosion-resistant material. The internal burst pressure of the housing is 1.5 MPaG or higher. The liquid flow rate per unit membrane surface area of the hollow fiber membranes is at least 0.10 mL / (cm2 × min) and less than 0.40 mL / (cm2 × min).

Description

Corrosive gas supply equipment

[0001] This disclosure relates to a corrosive gas supply device. This application claims priority to Japanese Patent Application No. 2024-109165, filed July 5, 2024, and incorporates by reference all of the contents of the above-mentioned Japanese application.

[0002] While aeration systems, which bubble gas into liquids, have been used in water purification systems to dissolve gases into liquids, a more efficient method is the use of porous membranes. In recent years, in the production of ultrapure water containing ozone, which has been increasingly used in cleaning processes in the semiconductor industry, this type of gas dissolution method using porous membranes is used exclusively because of the problems of dissolution efficiency and turbidity caused by bubbles. In particular, gas dissolution modules, which contain a large number of bundled porous hollow fiber membranes, have the advantage of high dissolution efficiency per unit volume. In this module, ultrapure water is passed through one of the inner and outer surfaces of the porous hollow fiber membranes, and ozone gas is passed through the other, allowing ozone to be efficiently dissolved into the ultrapure water through the membrane.

[0003] In particular, for the ozone water production application, fluororesin is used for the module as a material that can withstand the extremely strong oxidizing power of ozone. Polytetrafluoroethylene hollow fiber membranes are used as the fluororesin because of their excellent material properties, such as chemical resistance and heat resistance (see Patent Document 1). Furthermore, the dimensions of the hollow fiber membrane are preferably an average inner diameter of 0.3 mm to 8 mm, an outer diameter of 1 mm to 10 mm, and a wall thickness of 0.3 mm to 1 mm, and a water pressure resistance of 0.6 MPa is exemplified (see Patent Document 2).

[0004] JP-A-8-196879 JP-A-7-213880

[0005] The corrosive gas supply device of the present disclosure is a corrosive gas supply device capable of supplying a corrosive gas to a liquid supplied to the outside or inside of a hollow fiber membrane, and comprises an air supply module, a liquid supply mechanism that supplies the liquid to the air supply module, and a corrosive gas supply mechanism that supplies the corrosive gas to the air supply module, wherein the air supply module has a housing and a plurality of hollow fiber membranes made primarily of polytetrafluoroethylene or modified polytetrafluoroethylene, the hollow fiber membranes have an average outer diameter D2 of 0.60 mm or less and an average inner diameter D1 of 0.36 mm or less, and have a water pressure resistance and internal burst pressure of 1.5 MPaG or more, at least the inner circumferential surface of the housing is made of a corrosion-resistant material, the internal burst pressure of the housing is 1.5 MPaG or more, and the liquid flow rate per unit membrane area of ​​the hollow fiber membranes is 0.10 [ml / (cm ２ × min)] or more 0.40 [ml / (cm ２ × minutes).

[0006] FIG. 1 is a schematic diagram showing a corrosive gas supply device according to one embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view showing a fitting-assembly type air supply module according to one embodiment of the present disclosure. FIG. 3 is a schematic perspective view showing a hollow fiber membrane according to one embodiment of the present disclosure. FIG. 4 is a cross-sectional view of the hollow fiber membrane of FIG. 3 taken along line A-A. FIG. 5 is a schematic cross-sectional view showing a welding-assembly type air supply module according to another embodiment. FIG. 6 is a graph showing the correlation between the pressure of the corrosive gas and liquid and the concentration of the resulting ozone water in a corrosive gas supply device according to one embodiment of the present disclosure.

[0007] [Problem to be Solved by the Present Disclosure] In recent years, supply systems for corrosive gases such as ozone have been adopted for a variety of applications, including semiconductors, food, pharmaceuticals, and wastewater treatment. While a supply system for such corrosive gases has been proposed for organic wastewater treatment, dissolving corrosive gases at concentrations ranging from 10 ppm to 40 ppm or more (Fuji Times Vol. 77, Life Hygiene 18-6), a more efficient and compact system capable of oxidatively decomposing solutes and suspended solids by dissolving ozone at higher concentrations is required. For example, when used for resist stripping in the semiconductor field, a system that efficiently generates ozone water at even higher concentrations is required. Furthermore, while hollow fiber membranes need to be thinner to further improve gas diffusibility, they need to be extremely thin to improve pressure resistance. However, conventional supply systems are limited to systems that recirculate pure water inside, which poses the challenge of achieving both corrosive gas diffusibility and pressure resistance.

[0008] An object of the present disclosure is to provide a corrosive gas supply device that is compact and has excellent corrosive gas supply performance.

[0009] Effect of the Present Disclosure The corrosive gas supply device of the present disclosure can be made compact and has excellent corrosive gas supply performance.

[0010] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described.

[0011] (1) The corrosive gas supply device of the present disclosure is a corrosive gas supply device capable of supplying a corrosive gas to a liquid supplied to the outside or inside of a hollow fiber membrane, and includes an air supply module, a liquid supply mechanism that supplies the liquid to the air supply module, and a corrosive gas supply mechanism that supplies the corrosive gas to the air supply module, wherein the air supply module has a housing and a plurality of hollow fiber membranes made primarily of polytetrafluoroethylene or modified polytetrafluoroethylene, the hollow fiber membranes have an average outer diameter D2 of 0.60 mm or less and an average inner diameter D1 of 0.36 mm or less, and have a water pressure resistance and internal burst pressure of 1.5 MPaG or more, at least the inner circumferential surface of the housing is made of a corrosion-resistant material, the internal burst pressure of the housing is 1.5 MPaG or more, and the hollow fiber membranes have a liquid flow rate per unit membrane area of ​​0.10 [ml / (cm ２ × min)] or more 0.40 [ml / (cm ２ × minutes).

[0012] The corrosive gas supply device includes an air supply module, a liquid supply mechanism for supplying the liquid to the air supply module, and a corrosive gas supply mechanism for supplying the corrosive gas to the air supply module. The air supply module has a housing and a plurality of porous hollow fiber membranes composed primarily of polytetrafluoroethylene or modified polytetrafluoroethylene. The hollow fiber membranes have an average outer diameter D2 of 0.60 mm or less and an average inner diameter D1 of 0.36 mm or less, thereby achieving both high water pressure resistance and internal burst pressure of 1.5 MPaG or more and high gas dissolution efficiency while maintaining excellent permeability. Furthermore, the ability to operate the corrosive gas supply device at high pressures makes it possible to suppress the generation of bubbles caused by decomposition gases such as carbon dioxide, thereby promoting the decomposition of organic matter in wastewater within the module housing. At least the inner circumferential surface of the housing of the air supply module is made of a corrosion-resistant (corrosive gas resistant) material, and the burst internal pressure of the housing is 1.5 MPaG or more, so that air can be supplied under high pressures of the corrosive gas and liquid. This allows the air supply module to have a high air supply capacity and reduce deformation, buckling, etc. of the hollow fiber membrane and the housing. Therefore, the air supply module can safely and stably generate a high-concentration corrosive gas solution according to Henry's law, and can improve the durability of the corrosive gas supply device. Furthermore, since the hollow fiber membrane is mainly composed of polytetrafluoroethylene or modified polytetrafluoroethylene and at least the inner circumferential surface of the housing is made of the above material, it has excellent resistance to corrosive gases. Furthermore, the liquid flow rate per unit membrane area of ​​the hollow fiber membrane is 0.10 [ml / (cm ２ × min)] or more 0.40 [ml / (cm ２ x minutes)], a highly concentrated corrosive gas solution can be obtained. Therefore, the corrosive gas supply device can be made compact and has excellent corrosive gas supply performance.

[0013] Here, "major component" refers to the component with the highest content ratio in terms of mass, e.g., a component with a content ratio of 70% by mass or more. "Average outer diameter" refers to the average value of the outer diameters at two arbitrary points when the cross section of the hollow fiber membrane is circular. When the cross section of the hollow fiber membrane is elliptical, the minor and major diameters are measured at two locations, and the average value is defined as the average outer diameter. Furthermore, when the cross section of the hollow fiber membrane is a general circle or an irregular cross section other than an ellipse, edge information on the outer shape of the cross section is extracted to approximate a circle, and the obtained inner circumference is divided by pi to define the average outer diameter. Specifically, the average outer diameter can be measured by the following procedure. First, the hollow fiber membrane is sliced ​​in a plane perpendicular to the longitudinal direction and observed under an electron microscope so that the entire cross section is visible. The outer diameter is measured at two positions approximately diagonally opposite each other on the cross section (positions with a phase difference of approximately 90 degrees), and the average value is defined as the average outer diameter (D2). The "average inner diameter" refers to the average value of the inner diameters at two arbitrary points. The average inner diameter can be measured by the following procedure. First, the hollow fiber membrane is sliced ​​in a plane perpendicular to the longitudinal direction, and the cross section is observed under an electron microscope so that the entire cross section is visible. The inner diameter is measured at two positions that are approximately diagonal to each other on the cross section (positions that are approximately 90 degrees out of phase), and the average value is defined as the average inner diameter (D1). Furthermore, the "G" after the pressure units "MPaG" and "kPaG" indicates gauge pressure.

[0014] The "water-resistant pressure" refers to the pressure at which water begins to leak from one side of a membrane when water pressure is applied to the other side, and is also called the water leakage pressure. Generally, the larger the pore size of the through-holes, the easier water leakage occurs and the lower the water-resistant pressure, while the smaller the pore size, the higher the water-resistant pressure. Specifically, the water-resistant pressure is measured in accordance with JIS-L1092 (2009). Specifically, the lumen of the hollow fiber membrane is filled with water, and the water pressure applied to the lumen is continuously increased until water droplets appear on the outer surface of the hollow fiber membrane, similar to sweat coming from the skin. The "burst internal pressure" refers to the pressure at which the membrane bursts when water pressure is applied to one side. Generally, the smaller the average thickness / average internal diameter, the lower the burst internal pressure, and the larger the average thickness / average internal diameter, the higher the burst internal pressure. Specifically, the inner cavity of the hollow fiber membrane is filled with water, and the water pressure in the inner cavity is continuously increased until the hollow fiber membrane ruptures and water starts to leak out, which is the pressure at which the membrane ruptures.

[0015] The "membrane area" of the module is calculated by the following formula, where the average value of the average outer diameter and the average inner diameter is the neutral diameter, the effective length of the hollow fiber membrane is the distance between the inner boundaries of the potting parts at both ends, and the number of hollow fiber membranes installed is A. Membrane area [cm ２ ] = pi 3.14 × neutral diameter [cm] × effective length [cm] × A [units] The above operating condition "liquid flow rate / membrane area (ratio of liquid flow rate to membrane area)" is calculated using the following formula: Liquid flow rate / membrane area [ml / (cm ２ x min)]=liquid flow rate [ml / min] / membrane area [cm ２ ]

[0016] (2) In the above (1), ozone gas [400 g / m ３ ], the pressure of the ozone gas is P [MPaG], and the liquid is pure water, the concentration of the resulting ozone water N [mg / L] may satisfy the following formula: 180P + 20≦N≦250P + 39 When the pressure of the ozone gas is P [MPaG] and the liquid is pure water, and the concentration of the resulting ozone water N [mg / L] satisfies the above formula, a high-concentration ozone gas solution can be obtained more efficiently.

[0017] (3) In the above (1) or (2), the liquid flow rate per unit membrane area of ​​the hollow fiber membrane [ml / (cm ２ The ratio of the pressure [kPaG] of the corrosive gas to the liquid flow rate per unit membrane area [ml / (cm ２ The ratio of the pressure [kPaG] of the corrosive gas to the liquid flow rate per unit membrane area of ​​the hollow fiber membrane [ml / (cm ２ When the time required for the reaction to be carried out is 400 or more and the pressure of the corrosive gas is 1.5 MPaG or less, a highly concentrated corrosive gas solution can be efficiently obtained.

[0018] [Details of the Embodiments of the Present Disclosure] Hereinafter, a corrosive gas supply device according to each embodiment of the present disclosure will be described in detail with reference to the drawings.

[0019] <Corrosive Gas Supply Device> The corrosive gas supply device of the present disclosure is a corrosive gas supply device capable of supplying a corrosive gas to a liquid supplied to the outside or inside of a hollow fiber membrane. The corrosive gas supply device can be used in a variety of fields. The corrosive gas supply device can be used for a variety of purposes, such as purifying or neutralizing semiconductors, electronic devices, cleaning water for pharmaceutical applications, industrial wastewater, river water, lake water, pool water, public bath water, etc., water treatment applications for drinking water and industrial water, etc., and enriching specific gases by permeating corrosive gases through liquids.

[0020] A corrosive gas aeration device according to one embodiment of the present disclosure employs an external perfusion system in which a liquid is supplied to the outside of a hollow fiber membrane. The external perfusion system is an operating method in which a liquid with a higher viscosity than the corrosive gas is passed through the hollow fiber membrane so that it contacts the outer surface of the hollow fiber membrane, and the corrosive gas is passed through the lumen of the hollow fiber membrane. The adoption of the external perfusion system for the corrosive gas aeration device can prevent clogging due to the adhesion of organic matter to the lumen of the hollow fiber membrane, particularly when treating wastewater, and the corrosive gas aeration device can utilize the sealed space within the module housing as a reactor. The external perfusion system may also be employed to reduce pressure loss.

[0021] The corrosive gas supply device includes an air supply module, a liquid supply mechanism for supplying liquid to the air supply module, and a corrosive gas supply mechanism for supplying the corrosive gas to the air supply module. The air supply module includes a housing and a plurality of the hollow fiber membranes. The air supply module can be either an integrated type in which the air supply module is fixed within various devices, or an exchangeable cartridge type in which the housing and a membrane member having a plurality of hollow fiber membranes are independent and the membrane member is inserted into the housing. The corrosive gas supply device uses ultrafine hollow fiber membranes in the air supply module. The corrosive gas supply device is equipped with ultrafine, thin hollow fiber membranes. Ultrapure water is flowed so as to contact the outer surface of the porous hollow fiber membrane, and a corrosive gas is flowed through the hollow fiber membrane lumen, allowing the corrosive gas to efficiently dissolve in the ultrapure water through the membrane. The corrosive gas may be, for example, ozone, chlorine, hydrogen sulfide, sulfurous acid, nitrous acid, or ammonia.

[0022] 1 shows a corrosive gas supply system 100 according to one embodiment of the present disclosure. The corrosive gas supply system 100 includes an air supply module 50, a liquid supply mechanism 30 that supplies liquid to the air supply module 50, and a corrosive gas supply mechanism 20 that supplies corrosive gas to the air supply module 50. The corrosive gas supply system 100 may also include a control unit (not shown) that controls on-off valves and the like so that the flow rate of the liquid and the flow rate of the corrosive gas are predetermined flow rates.

[0023] Liquid supply mechanism 30 may have an on-off valve or a pressure adjustment valve for adjusting the supply pressure of the liquid so that the high-pressure liquid can come into contact with the corrosive gas inside housing 11. In this embodiment, liquid supply mechanism 30 supplies liquid at an appropriate pressure toward liquid supply port 7 of housing 11 using pressure adjustment valve 31. Furthermore, liquid supply mechanism 30 has a pump (not shown) upstream of pressure adjustment valve 31 for sending liquid to the piping.

[0024] The corrosive gas supply mechanism 20 has a pressure regulating valve 21 for regulating the supply pressure of the corrosive gas so that the high-pressure corrosive gas can come into contact with the liquid inside the housing 11. The corrosive gas supply mechanism 20 supplies the corrosive gas at an appropriate pressure toward the gas supply port 9 of the housing 11 by the pressure regulating valve 21.

[0025] The corrosive gas solution outlet 45 has a pressure adjusting valve (resistor) 46 for adjusting the pressure of the corrosive gas solution in the module to a higher pressure, thereby generating an appropriate pressure in the module.

[0026] The exhaust unit 40 has a pressure adjusting valve (resistor) 41 for adjusting the pressure of the corrosive gas in the module to a higher pressure, and generates an appropriate corrosive gas pressure in the module.

[0027] In the piping used in the corrosive gas supply mechanism 20, the corrosive gas solution outflow portion 45, and the exhaust portion 40, the surfaces that come into contact with the corrosive gas solution may be made of a material with excellent corrosion resistance. Examples of materials with excellent corrosion resistance include stainless steel, nickel alloy, titanium alloy, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP).

[0028] [Air Supply Module] Figure 2 shows an example of an air supply module according to an embodiment of the present disclosure, an air supply module 50A having a fitting-type housing. The air supply module 50A includes a membrane element 2 having a plurality of hollow fiber membranes 1 aligned in one direction, and a cylindrical housing 11A that houses the membrane element 2. The air supply module 50A is a type that allows gas to pass through the hollow fiber membranes 1 and supply the gas to a liquid supplied outside the hollow fiber membranes 1. The corrosive gas supply device 100 includes the air supply module 50A, a liquid supply mechanism 30 that supplies liquid to the outside of the hollow fiber membranes 1 in the air supply module 50A, and a corrosive gas supply mechanism 20 that supplies corrosive gas to the liquid supplied outside the hollow fiber membranes 1. The corrosive gas supply device 100 may also include a control unit (not shown) that controls on-off valves and the like to maintain the flow rates of the liquid and the corrosive gas at predetermined flow rates.

[0029] The membrane element 2 has a first sealing portion 5 that holds first ends of the plurality of hollow fiber membranes 1 and a second sealing portion 4 that holds second ends of the plurality of hollow fiber membranes 1. In the first sealing portion 5 and the second sealing portion 4, a potting agent is filled between the hollow fiber membranes 1 and between the bundle of hollow fiber membranes 1 and the inner surface of the housing.

[0030] The potting agent is primarily composed of resin, rubber, or elastomer. The primary component of the potting agent is not particularly limited, but examples include epoxy resin, urethane resin, ultraviolet-curable resin, fluororesin, silicone resin, polyamide resin, and polyolefin resin such as polyethylene or polypropylene. Among these, fluororesin and silicone resin are preferred from the viewpoints of adhesiveness and chemical resistance to the hollow fiber membrane 1 primarily composed of polytetrafluoroethylene or modified polytetrafluoroethylene (modified PTFE), and to the housing 11A, at least the inner circumferential surface of which is made of a corrosion-resistant material.

[0031] The air supply module 50A comprises a cylindrical housing 11A, a first sleeve 14 attached to a first end of the housing 11A and provided with an engagement structure for engaging the liquid outlet 8A and the first sealing portion 5, a first cap 15 sealing the end on the first sleeve 14 side and provided with a gas supply port 9A, a second sleeve 12 attached to a second end of the housing 11A and provided with an engagement structure for engaging the liquid supply port 7A and the second sealing portion 4, and a second cap 13 sealing the end on the second sleeve 12 side and provided with a gas outlet 19A.

[0032] At least the inner peripheral surface of the housing 11A is made of a corrosion-resistant material. Examples of the corrosion-resistant material include organic materials such as polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and tetrafluoroethylene-hexafluoropropylene copolymer. Examples of the corrosion-resistant material include inorganic materials such as stainless steel, nickel alloy, and titanium alloy.

[0033] In order to increase the safety factor, the outer periphery of the housing 11A may be further provided with a reinforcing structure in which metal wire or carbon fiber is wrapped around it.

[0034] The burst internal pressure of the housing 11A is 1.5 MPaG or more, and may be 2.0 MPaG or more. When the burst internal pressure of the housing 11A is 1.5 MPaG or more, gas can be supplied under high pressure conditions of the corrosive gas and the liquid.

[0035] When the material of at least the inner peripheral surface of housing 11A is primarily made of polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, or tetrafluoroethylene-hexafluoropropylene copolymer resin, housing 11A may have a ratio of average thickness to average inner diameter of 0.05 or more. Having a ratio of average thickness to average inner diameter of housing 11A of 0.05 or more can improve mechanical strength, and can increase the burst internal pressure of housing 11A to 1.5 MPaG or more.

[0036] When the material of at least the inner peripheral surface of the housing 11A is primarily stainless steel, a nickel alloy, or a titanium alloy, the ratio of the average thickness to the average inner diameter of the housing 11A may be 0.007 or more. When the ratio of the average thickness to the average inner diameter of the housing 11A is 0.007 or more, the mechanical strength can be improved, and the burst internal pressure of the housing 11A can be increased to 1.5 MPaG or more.

[0037] The air supply module 50A has a liquid supply port 7A, through which raw water is supplied, and a liquid discharge port 8A, through which the liquid is discharged, on its side. The first end of the air supply module 50A has a gas supply port 9A, through which a corrosive gas is supplied, and the second end has a gas discharge port 19A, through which the corrosive gas that has permeated the hollow fiber membranes 1 is discharged. The arrangement and orientation of the gas supply port 9A and the gas discharge port 19A are not particularly limited and can be configured according to the state in which the air supply module 50A is installed.

[0038] The raw water supplied from the liquid supply port 7A toward the outside of the hollow fiber membrane 1 is supplied into the housing 11A. Then, the liquid after the aeration treatment is discharged from the liquid discharge port 8A provided on the side surface near the second end of the housing 11A.

[0039] The air supply module 50A has a housing 11A whose inner surface is made of a corrosion-resistant material, and a plurality of hollow fiber membranes 1 whose main component is polytetrafluoroethylene or modified polytetrafluoroethylene, and therefore has excellent chemical resistance. Therefore, the type of liquid is not particularly limited, and various liquids can be used depending on the purpose, such as pure water, drinking water, chemical solutions, and waste liquids.

[0040] In addition, the gas supplied into the hollow fiber membrane 1 from the gas supply port 9A is sucked toward the gas discharge port 19A and discharged from the tip of the gas discharge port 19A while being supplied to the liquid supplied outside the hollow fiber membrane 1.

[0041] Pressure of corrosive gas in the air supply module 50A [kPaG] / Liquid flow rate per unit membrane area of ​​hollow fiber membrane [ml / (cm ２ The lower limit of the ratio of corrosive gas pressure [kPaG] / liquid flow rate per unit membrane area of ​​hollow fiber membrane [ml / (cm ２ When the pressure of the corrosive gas in the air supply module 50A [kPaG] / liquid flow rate per unit membrane area of ​​the hollow fiber membrane [ml / (cm ２ The upper limit of the time (minutes) can be set to 10,000.

[0042] The lower limits of the corrosive gas pressure and the liquid pressure may be 0.10 MPaG or 0.45 MPaG. When the corrosive gas pressure and the liquid pressure are 0.10 MPaG or higher, a more highly concentrated corrosive gas solution can be obtained. The upper limits of the corrosive gas pressure and the liquid pressure may be 2 MPaG or 1.5 MPaG. When the corrosive gas pressure and the liquid pressure are 2 MPaG or lower, the safety of the hollow fiber membrane 1 and the housing 11 can be improved.

[0043] Liquid flow rate per unit membrane area of ​​hollow fiber membrane 1 [ml / (cm ２ The ratio of the pressure of the corrosive gas [kPaG] to the liquid flow rate per unit membrane area of ​​the hollow fiber membrane 1 [ml / (cm ２ The ratio of the pressure of the corrosive gas [kPaG] to the liquid flow rate per unit membrane area of ​​the hollow fiber membrane [ml / (cm ２When the time required for the reaction is 400 or more and the pressure of the corrosive gas is 1.5 MPaG or less, a highly concentrated corrosive gas solution can be efficiently obtained.

[0044] The liquid flow rate per unit membrane area of ​​the hollow fiber membrane 1 is 0.10 [ml / (cm ２ × min)] or more, and ２ The liquid flow rate per unit membrane area of ​​the hollow fiber membrane 1 may be 0.10 [ml / (cm ２ × min)] or more, the hollow fiber membranes 1 can be effectively utilized, and the module can be made the minimum size required. In addition, the liquid flow rate per unit membrane area of ​​the hollow fiber membranes 1 is 0.40 [ml / (cm ２ × min)]. The liquid flow rate per unit membrane area of ​​the hollow fiber membrane 1 is less than 0.40 [ml / (cm ２ × minutes)], a highly concentrated corrosive gas solution can be obtained more efficiently.

[0045] [Hollow Fiber Membrane] The hollow fiber membrane 1 shown in Figures 3 and 4 is an expanded porous body primarily composed of polytetrafluoroethylene or modified polytetrafluoroethylene. Polytetrafluoroethylene or modified polytetrafluoroethylene is a fluororesin with excellent chemical resistance and solvent resistance. By using polytetrafluoroethylene or modified polytetrafluoroethylene as the primary component, the hollow fiber membrane 1 improves the selectivity of the types of liquids and gases supplied to the air supply module 50A. Furthermore, because polytetrafluoroethylene and modified polytetrafluoroethylene are highly hydrophobic fluororesins, liquid leakage from the hollow fiber membrane 1 is prevented and gas permeability can be improved.

[0046] Modified polytetrafluoroethylene refers to polytetrafluoroethylene in which hexafluoropropylene (HFP), alkyl vinyl ether (AVE), chlorotrifluoroethylene (CTFE), etc. are copolymerized with tetrafluoroethylene in a molar ratio of 1 / 50 or less.

[0047] The upper limit of the average outer diameter D2 of the hollow fiber membrane 1 is 0.60 mm, and may be 0.50 mm. When the average outer diameter D2 is 0.60 mm or less, gas can be supplied under high corrosive gas and liquid pressure conditions while maintaining excellent permeability. Furthermore, deformation, buckling, etc. of the hollow fiber membrane 1 can be reduced, and therefore the corrosive gas supply device 100 can produce a highly concentrated corrosive gas solution. On the other hand, the lower limit of the average outer diameter D2 of the hollow fiber membrane 1 may be 0.10 mm. When the average outer diameter D2 is 0.10 mm or more, pressure loss can be reduced.

[0048] The upper limit of the average inner diameter D1 of the hollow fiber membrane 1 is 0.36 mm, and may be 0.20 mm. When the average inner diameter D1 is 0.36 mm or less, gas can be supplied under high corrosive gas and liquid pressure conditions while maintaining excellent permeability. Furthermore, deformation, buckling, etc. of the hollow fiber membrane 1 can be reduced, and therefore the corrosive gas supply device 100 can produce a highly concentrated corrosive gas solution. On the other hand, the lower limit of the average inner diameter D1 of the hollow fiber membrane 1 may be 0.05 mm. When the average inner diameter D1 is 0.05 mm or more, pressure loss can be reduced.

[0049] The lower limit of the average thickness T1 of the hollow fiber membrane 1 may be 0.05 mm or 0.06 mm. On the other hand, the upper limit of the average thickness T1 of the hollow fiber membrane 1 may be 0.19 mm or 0.18 mm. When the average thickness T1 is 0.05 mm or more, sufficient pressure resistance strength can be obtained, and rupture due to internal pressure and buckling due to external pressure can be prevented. On the other hand, when the average thickness T1 is 0.19 mm or less, sufficient gas permeability can be obtained. The "average thickness" of the hollow fiber membrane 1 can be calculated by dividing (average outer diameter - average inner diameter) by 2.

[0050] The average thickness / average inner diameter of the hollow fiber membrane 1 may be 0.50 or more, or 0.60 or more. Furthermore, the average thickness / average inner diameter of the hollow fiber membrane 1 may be 0.50 or more, and the lower limit of the average inner diameter D1 may be 0.05 mm or 0.10 mm. On the other hand, the average thickness / average inner diameter of the hollow fiber membrane 1 may be 0.50 or more, and the upper limit of the average outer diameter D2 may be 0.60 mm or 0.36 mm. Furthermore, the average thickness / average inner diameter of the hollow fiber membrane 1 may be 0.60 or more, and the upper limit of the average inner diameter D1 may be 0.25 mm, and the upper limit of the average outer diameter D2 may be 0.5 mm.

[0051] The rupture internal pressure of the hollow fiber membrane 1 is 1.5 MPaG or more, and may be 2 MPaG or more. Having a rupture internal pressure of 1.5 MPaG or more reduces plastic deformation, rupture, and buckling of the hollow fiber membrane 1, preventing performance degradation and failure of the hollow fiber membrane 1, and enabling the air supply module 50A to operate safely and stably under conditions of high corrosive gas and liquid pressure. In particular, even in the event of a sudden fluctuation in the corrosive gas pressure or liquid pressure, such as when either the corrosive gas pressure or the liquid pressure is shut down, the air supply module 50A will not rupture, ensuring safety.

[0052] The buckling external pressure of the hollow fiber membrane 1 may be 1.0 MPaG or more, or 1.5 MPaG or more. When the buckling external pressure of the hollow fiber membrane 1 is 1.0 MPaG or more, air can be supplied under high corrosive gas and liquid pressures. This allows the air supply module 50A to have a high air supply capacity and produce a highly concentrated corrosive gas solution. Here, the "buckling external pressure" refers to the pressure at which the lumen of the hollow fiber membrane collapses when water pressure is applied from the outer surface of the hollow fiber membrane 1. The buckling external pressure is measured using the following procedure. First, the liquid outlet 8 located on the end face of the housing 11 of the air supply module 50 shown in FIG. 1 is sealed. Then, raw water is supplied from the liquid supply mechanism 30 toward the liquid supply port 7 to fill the outer surface of the hollow fiber membrane 1 with raw water, and in this state where the water pressure is increased, a corrosive gas is supplied from the corrosive gas supply mechanism 20 toward the gas supply port 9 located at the first end of the housing 11, and the change in the differential pressure of the corrosive gas is measured and used as the buckling external pressure.

[0053] The lower limit of the porosity of the hollow fiber membrane 1 may be 30% or 40%. On the other hand, the upper limit of the porosity of the hollow fiber membrane 1 is not particularly limited, and may be 80% or 70%. When the porosity of the hollow fiber membrane 1 is 30% or more, the gas permeability can be improved and the air supply performance of the hollow fiber membrane 1 can be improved. When the porosity of the hollow fiber membrane 1 is 80% or less, the mechanical strength and durability of the hollow fiber membrane 1 can be maintained and damage such as rupture due to internal pressure can be prevented.

[0054] The "porosity" refers to the ratio of the total volume of pores to the total volume of the hollow fiber membrane 1, and is calculated based on the sample volume, sample weight, and the true specific gravity of polytetrafluoroethylene (PTFE), 2.17 g / cm ３ First, the average outer diameter D2 and the average inner diameter D1 of the hollow fiber membrane 1 for which the porosity is to be measured are measured using an SEM. Next, the length (L) of the hollow fiber membrane 1 for which the porosity is to be measured is measured to the nearest 1 mm. Next, the weight (W) of the hollow fiber membrane 1 is measured to the nearest 0.0001 g using an electronic balance. Then, based on the above measured values, the porosity [%] is calculated using the following formula: Porosity [%] = {1 - volume of resin only [cm ３ ]÷Total volume of hollow fiber membrane [cm ３]}×100 = {1-(W[g]÷ρ[g / cm ３ ])÷(π(D2 ２ [mm ２ ]-D1 ２ [mm ２ ]) × L [mm] ÷ 1000)} × 100 where "ρ" represents the true specific gravity of polytetrafluoroethylene, 2.17 [g / cm ３ ].

[0055] The lower limit of the average pore size of the hollow fiber membrane 1 may be 3 nm or 4 nm. On the other hand, the upper limit of the average pore size of the hollow fiber membrane 1 may be 50 nm or 40 nm. When the average pore size is 3 nm or more, the air supply performance can be improved. On the other hand, when the average pore size is 50 nm or less, the water pressure resistance can be maintained and liquid leakage due to the inclusion of impurities can be prevented. The average pore size can be measured, for example, with a pore size distribution measuring device (a perm porometer "CFP-1500A: Porous" manufactured by Porous Materials, Inc.) using GALWICK (propylene, 1,1,2,3,3,3-hexahydrofluoric acid oxide; manufactured by Porous Materials, Inc.) as the liquid. Specifically, it can be determined as follows. First, the relationship between the differential pressure applied to the membrane and the air flow rate passing through the membrane is measured when the membrane is dry and when the membrane is wet with a liquid, and the resulting graphs are designated as the dry curve and wet curve, respectively. The differential pressure at the intersection of the curve with the wet curve and the curve with the flow rate of the dry curve halved is designated as P (PaG). The mean flow diameter is adopted as the mean pore diameter using the following formula: Mean flow diameter d (μm) = cγ / P, where c is a constant equal to 2860, and γ is the surface tension of the liquid (dynes / cm). Even with this method, the measurement pressure becomes high enough to exceed the measurement limit when the pore diameter is less than 20 nm, so a pore size distribution measuring instrument can be used in which the air is replaced with a liquid such as IPAG. Other measurement methods include, for example, a pore size distribution measurement method using a gas adsorption method that applies the capillary condensation phenomenon, and a mercury intrusion method or pure water intrusion method that measures the pore size distribution using the pressure at which a liquid that is repelled by the pores penetrates into the pore diameter, the intruded volume, and the Washburn equation.

[0056] The water pressure resistance of the hollow fiber membrane 1 is 1.5 MPaG or more, and may be 2 MPaG or more. When the water pressure resistance of the hollow fiber membrane 1 is 1.5 MPaG or more, the liquid can be safely and stably supplied to the hollow fiber membrane 1 even when the liquid pressure is high.

[0057] The lower limit of the filling rate of the hollow fiber membranes 1 in the air supply module 50A may be 30% or 40%. Meanwhile, the upper limit of the filling rate of the hollow fiber membranes 1 may be 70% or 60%. A filling rate of the hollow fiber membranes 1 of 30% or more can improve the air supply performance of the air supply module 50A. Meanwhile, a filling rate of the hollow fiber membranes 1 of 70% or less can prevent the hollow fiber membranes 1 from collapsing when packed into the housing 11A, and can improve the packing properties of the hollow fiber membranes 1 into the housing 11A. The air supply module 50A has excellent air supply performance because the filling rate of the hollow fiber membranes 1, which have high porosity and bubble point, is 30% or more and 70% or less. Here, the "filling rate of hollow fiber membranes" refers to the packing density of hollow fiber membranes 1 packed in the housing 11A, and is the ratio (%) of the sum of the cross-sectional areas occupied by each hollow fiber membrane 1, calculated from the outer diameter of each hollow fiber membrane 1 packed, to the cross-sectional area of ​​the lumen of the housing 11A perpendicular to the longitudinal direction of the hollow fiber membranes 1 packed in the housing 11A.

[0058] In addition to polytetrafluoroethylene and modified polytetrafluoroethylene, the hollow fiber membrane 1 may contain other fluororesins and additives within a range that does not impair the desired effects of the present disclosure. Examples of the additives include inorganic fillers, metal powders, metal oxide powders, and metal sulfide powders for improving abrasion resistance, preventing low-temperature flow, and facilitating pore formation.

[0059] [Method for manufacturing hollow fiber membrane] Next, an example of a method for manufacturing the hollow fiber membrane will be described. As exemplified in International Publication No. 2020 / 084930, the method for manufacturing the hollow fiber membrane may include, for example, a molding step of molding a hollow fiber membrane into a tubular shape using raw materials for forming the hollow fiber membrane, a heating step of heating the tubular molded product at a temperature equal to or higher than the melting point of the raw materials for forming the hollow fiber membrane, a cooling step of cooling the molten resin, and a stretching step of stretching the non-porous tubular molded product to make it porous. In this way, by stretching the hollow fiber membrane after molding, a porous hollow fiber membrane can be formed while reducing the diameter of the pores of the hollow fiber membrane. In this case, the heat of fusion of the non-porous tube before stretching may be in the range of 30 J / g to 45 J / g. By having the heat of fusion of 30 J / g or more, the breaking elongation is increased, and it is possible to achieve porousness by stretching at a stretch ratio of 2 or more. On the other hand, by making the heat of fusion 45 J / g or less, the non-porous tube before stretching is less likely to become brittle, and therefore it is possible to achieve porousness by stretching at a stretch ratio of 2 or more. Methods for adjusting the heat of fusion include a method of adjusting the degree of polymerization of the PTFE fine powder to be low, a method of adjusting by irradiating ionizing radiation such as gamma rays to a PTFE fine powder with a high degree of polymerization and a heat of fusion of less than 30 J / g, and a method of adjusting by irradiating ionizing radiation such as gamma rays to a molded non-porous tube.

[0060] The heat of fusion is measured by the following procedure. 10 to 20 mg of sample is heated from room temperature to 245°C at 50°C / min, and then heated at 10°C / min to 365°C (first step). Next, it is cooled to 350°C at a rate of -10°C / min and held at 350°C for 5 minutes. It is further cooled from 350°C to 330°C at a rate of -10°C / min, and from 330°C to 305°C at a rate of -1°C / min (second step). Next, it is cooled from 305°C to 245°C at a rate of -50°C / min, and then heated from 245°C to 365°C at a rate of 10°C / min (third step). The sampling time is 0.5 seconds per sample. The endothermic amount in the first step is determined in the interval from 303 to 353°C, the exothermic amount in the second step in the interval from 318 to 309°C, and the endothermic amount in the third step is determined by integrating the interval of 48°C from the end of the endothermic curve (near 343°C). The endothermic amount in this third step is defined as the heat of fusion.

[0061] In the drawing process, a continuous drawing apparatus having a furnace disposed between a feed capstan and a take-up capstan, as exemplified in JP-A-59-178228, is used, and drawing can be performed by setting the peripheral speed of the take-up capstan higher than that of the feed capstan. The peripheral speed of the feed capstan is sometimes called the "feed speed" or "supply speed," and the peripheral speed of the take-up capstan is sometimes called the "winding speed" or "take-up speed."

[0062] The stretching ratio (winding peripheral speed / feed peripheral speed) in the stretching step may be 2 to 8 times, or may be 4 to 6 times. By setting the stretching ratio to 2 times or more, it is possible to make the non-porous tubular molded product porous. Furthermore, by setting the stretching ratio to 8 times or less, the resulting hollow fiber membrane can have sufficient burst strength and can have a pore size that allows it to have sufficient water pressure resistance.

[0063] The air supply module can be assembled by inserting the hollow fiber membranes into the module housing, and then sealing the ends by filling the gaps between the hollow fiber membranes at the ends with a thermoplastic fluororesin as a filler, and then heating and melting the filler at a temperature equal to or higher than its melting point, as described in Unexamined Utility Model Publication No. 1-136287. Examples of thermoplastic fluororesins include tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene and ethylene copolymer (ETFE), and polyvinylidene fluoride (PVDF).

[0064] [Other Embodiments] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the configurations of the above-described embodiments, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0065] While the above embodiment illustrates an air intake module having a fitting-type housing, the structure of the air intake module is not particularly limited. FIG. 5 is a schematic cross-sectional view of an air intake module 50B having an integrated, welded housing, which is an example of an air intake module according to another embodiment. The air intake module 50B shown in FIG. 5 includes a housing 11B having an integrated, welded housing. The side of the housing 11B is provided with a liquid supply port 7B through which raw water is supplied and a liquid outlet 8B through which liquid is discharged. The first end face of the housing 11B has a gas supply port 9B through which gas is supplied, and the second end face has a gas outlet 19B through which gas that has permeated the multiple hollow fiber membranes 1 is discharged. Note that, apart from the housing 11B, the components are similar to the air intake module 50A shown in FIG. 2, and therefore, the same reference numerals are used and a description thereof will be omitted.

[0066] Furthermore, by using this corrosive gas supply device, a two-phase fluid in which a corrosive gas and a corrosive gas solution are mixed in a flow path can be produced. Specifically, the corrosive gas is injected at a pressure of, for example, 0.1 MPaG or more and a liquid at a pressure equal to or greater than the corrosive gas pressure, and then the pressure of the solution is released to the atmosphere (0 MPaG), causing the corrosive gas to precipitate, thereby producing a two-phase fluid in which the solution and the corrosive gas are mixed. The greater the pressure difference between the corrosive gas and the pressure released, the greater the precipitation of the corrosive gas. The corrosive gas supply device capable of producing the above two-phase fluid can also be used, for example, in ozone cleaning devices and semiconductor cleaning devices.

[0067] In the above embodiment, the gas supply module of the corrosive gas supply device was operated in an external perfusion manner, in which, from the viewpoint of power efficiency, a liquid having a higher viscosity than the corrosive gas was passed so as to come into contact with the outer surface of the hollow fiber membrane, and the corrosive gas was passed through the lumen of the hollow fiber membrane. However, the internal perfusion manner may also be used, in which the flow of the corrosive gas and the liquid is reversed. The internal perfusion manner is a manner in which the corrosive gas can be supplied to the liquid supplied inside the hollow fiber membrane.

[0068] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0069] [Hollow fiber membrane test number 1] The raw material for the hollow fiber membrane was a non-porous PTFE tube obtained by blending an extrusion aid with a modified PTFE fine powder in the same manner as in WO 2020 / 084930, aging the powder, and then molding it into a tube by paste extrusion and heating it at a temperature above the melting point. The dimensions of the non-porous tube were adjusted by adjusting the dimensions of the mold (die and core), resulting in an average outer diameter D2 of 0.51 mm and an average inner diameter D1 of 0.30 mm. The heat of fusion was 23.63 J / g. Next, 0.75 kGy of gamma rays were irradiated to adjust the heat of fusion. As a result, the heat of fusion of hollow fiber membrane test number 1 was 35.17 J / g.

[0070] Furthermore, Tube Test No. 1 was heated in a coiled state at 350°C for 5 minutes or more to remelt, and then slowly cooled to 300°C or less at a cooling rate of -1°C / min or less. Tube Test No. 1 was then stretched in a continuous stretching device at a stretch ratio of 5 and a heating and stretching temperature of 170°C. The feed rate was 0.16 m / min and the take-up rate was 0.8 m / min. In this way, expanded porous PTFE hollow fiber membrane Test No. 1 was produced. The finished dimensions of Hollow Fiber Membrane Test No. 1 were an average outer diameter D2 of 0.290 mm, an average inner diameter D1 of 0.110 mm, an average thickness T1 of 0.090 mm, and an average thickness T1 / average inner diameter D1 ratio of 0.82. Furthermore, it was confirmed that the hollow fiber membrane test number 1 had an average pore size of 6 nm, a porosity of 43%, a buckling external pressure of 1 MPaG, a burst internal pressure of 1.9 MPaG, and a water pressure resistance of 1.9 MPaG or more. The average pore size was measured by a pure water intrusion method (pure water intrusion porosimeter Aquapore 10,000 psi type: manufactured by Porous Materials, Inc.). These physical property values ​​of hollow fiber membrane test number 1 are shown in Table 1.

[0071] The evaluation method for hollow fiber membranes is as follows. (1) Water-Resistant Pressure of Hollow Fiber Membranes The water-resistant pressure of hollow fiber membranes was measured using the following procedure. The lumen of a hollow fiber membrane was filled with water using a hand pump (T-50K, manufactured by Kyowa Corporation), and the water pressure on the lumen was continuously increased until water passed through the wall of the hollow fiber membrane and began to ooze out from the outer wall of the hollow fiber membrane like sweat. This was taken as the water-resistant pressure. (2) Rupture Internal Pressure of Hollow Fiber Membranes The burst internal pressure of hollow fiber membranes was measured using the following procedure. The lumen of a hollow fiber membrane was filled with water using a hand pump (T-50K, manufactured by Kyowa Corporation), and the water pressure on the lumen was continuously increased until the pressure at which the hollow fiber membrane ruptured and water began to leak out was measured. (3) Buckling External Pressure of Hollow Fiber Membranes The buckling external pressure of hollow fiber membranes was measured using the following procedure. The liquid outlet located on the side of the housing of the air supply module was sealed, the housing was filled with water, and water pressure was applied up to a predetermined pressure using a hand pump (Kyowa's "T-50K"), and the changes in gas flow rate and differential pressure were measured when gas was supplied from the gas supply port located on the side of the first end of the housing.

[0072]

[0073] As shown in Table 1, the relationship between the dimensional characteristics and the burst internal pressure, buckling external pressure, and water pressure resistance in hollow fiber membrane test number 1 was confirmed to be 1.5 MPaG or more when the average outer diameter D2 of the hollow fiber membrane was 0.60 mm or less, the average inner diameter D1 was 0.36 mm or less, and the average thickness / average inner diameter was 0.5 or more. Furthermore, the relationship between the burst internal pressure and the average thickness T1 / average inner diameter D1 in hollow fiber membrane test number 1 is as shown below, and the square of the correlation coefficient was 0.8707, indicating a high correlation. Burst internal pressure of hollow fiber membrane [MPaG] = -1.695 × ((thickness / average inner diameter) ２ ) + 3.6495 × (thickness / average inner diameter)

[0074] (Corrosive Gas Intake Device Test Nos. 31 to 47) An integrated, welded-type intake module with the intake casing shown in Figure 5 was prepared. PFA was used as the material for the intake casing test No. 11. 1,000 hollow fiber membranes, 500 mm long, of hollow fiber membrane test No. 1 listed in Table 1 were bundled and inserted into a PFA tube with an outer diameter of 19.05 mm, an average inner diameter of 15.88 mm, and an average thickness / average inner diameter = 0.1 (estimated internal burst pressure of 2.6 MPaG). The gaps between the hollow fiber membranes at the end were filled with FEP resin, and only the ends were heated to above the melting point of FEP (260°C) to seal the gaps between the hollow fiber membranes. The end faces were then scraped off to open the end faces of the hollow fiber membranes. The physical properties of the intake casing test No. 11 used are shown in Table 2.

[0075] Regarding the internal burst pressure of the casing, manufacturers provide data on the internal burst pressure of fluororesin tubes, for example (reference for internal burst pressure of fluororesin tubes: Publisher: Nichias, catalog file T44.pdf published December 2021, catalog number T44-2112-FT-BU-revised-2104). The relationship between the average thickness / average inner diameter and internal burst pressure of the PFA tube, calculated from the inner and outer diameters and internal burst pressure of the PFA tube disclosed in the above data, is as shown in the following formula, and the square of the correlation coefficient between the average thickness / average inner diameter and internal burst pressure is 0.9994, indicating a high correlation. From the formula below, for example, the average thickness / average inner diameter of a fluororesin casing may be 0.05 or more, 0.09 or more, or 0.14 or more. Internal burst pressure of PFA tube [MPaG] = -21.645 × ((average thickness / average inner diameter) ２ ) + 28.348 × (average thickness / average inner diameter)

[0076]

[0077] Thereafter, a PFA cap with an average inner diameter of 15.88 mm and an average thickness / average inner diameter of 0.1 or more was used as a corrosive gas supply and discharge port, and the body was heated to 315 ° C or higher, which is the melting point of PFA, so that it was continuous with the inner cavity of the body of the enclosure test number 11. The body was welded. Each port was connected to a PFA tube with an outer diameter of 6.35 mm, an average inner diameter of 3.95 mm, and an average thickness / average inner diameter of 0.3 (estimated burst internal pressure 6.5 MPaG) using a different diameter tube converter, and extended to form a system piping. The flow rate / membrane area was adjusted by connecting one unit of air supply modules with the same specifications in series.

[0078] (Evaluation of Air Supply Performance of Corrosive Gas Supply Device) The supply pressure of oxygen supplied to the ozone gas generator was 0.25 MPaG, the supply flow rate was 1 L / min, and the ozone gas concentration was 400 g / m ３The ozone gas was generated at a room temperature of 25°C. Pure water was passed through the outer surface of the hollow fiber membrane of each corrosive gas supply device at a pressure shown in Tables 3 to 5 at a rate of 0.4 L / min while the ozone gas was brought into contact with the lumen of the hollow fiber membrane, and the gas supply performance of corrosive gas supply devices Test Nos. 31 to 81 was evaluated. The dissolved ozone concentration [mg / L] of the ozone water produced at this time was measured. In the above evaluations, the pressure of the ozone gas and the liquid were adjusted using regulating valves while maintaining the liquid flow rate per unit membrane area of ​​the hollow fiber membrane at a set value.

[0079] The dissolved ozone concentrations in corrosive gas supply system test numbers 31 to 81 are shown in Tables 3 to 5. Also, Fig. 6 shows the correlation between the pressure of the corrosive gas and liquid and the dissolved ozone concentration of the produced ozonated water in corrosive gas supply system test numbers 31 to 36 (air supply module test number 21), corrosive gas supply system test numbers 48 to 53 (air supply module test number 22), and corrosive gas supply system test numbers 65 to 70 (air supply module test number 23).

[0080] The evaluation results shown in Tables 3 to 5 below were obtained when the ozone gas pressure was in the range of 0 MPaG to 0.25 MPaG. On the other hand, the results when the ozone gas pressure was 0.25 MPaG or higher were calculated from the relational expression between the corrosive gas (ozone gas) pressure and the ozone concentration shown in Figure 6. The relational expression between the corrosive gas pressure and the ozone concentration is as follows, and the square of the respective correlation coefficients was 0.997 or higher, indicating a very high correlation. (1) Air Intake Module Test No. 21 Ozone Water Concentration [ppm] = 196.3 × Ozone Gas Pressure [MPaG] + 20.834 Square of Correlation Coefficient: 0.9986 (2) Air Intake Module Test No. 22 Ozone Water Concentration [ppm] = 252.1 × Ozone Gas Pressure [MPaG] + 32.194 Square of Correlation Coefficient: 0.9998 (3) Air Intake Module Test No. 23 Ozone Water Concentration [ppm] = 242.4 × Ozone Gas Pressure [MPaG] + 38.455 Square of Correlation Coefficient = 0.9974

[0081]

[0082]

[0083]

[0084] As shown in Tables 3 to 5, the dissolved ozone concentration tended to increase as the pressure of the gas or liquid increased. As shown in Tables 3 to 5, the hollow fiber membrane had an average outer diameter D2 of 0.60 mm or less, an average inner diameter D1 of 0.36 mm or less, a water pressure resistance and a burst internal pressure of 1.5 MPaG or more, the inner peripheral surface of the housing was made of PFA, which is a corrosion-resistant material, the burst internal pressure of the housing was 1.5 MPaG or more, and the liquid flow rate per unit membrane area of ​​the hollow fiber membrane was 0.10 [ml / (cm ２ × min)] or more 0.40 [ml / (cm ２ In the corrosive gas supply device test numbers 31 to 81, in which the ozone concentration in the ozone water obtained is in the range of less than [× minutes], a favorable tendency is observed.

[0085] 6, the relationship between the pressure P [MPaG] of the corrosive gas (ozone gas) and the liquid (pure water) and the dissolved ozone concentration N [mg / L] of the ozone water in the corrosive gas supply device test numbers 31 to 36, test numbers 48 to 53, and test numbers 65 to 70 was 180P + 20 ≦ N ≦ 250P + 39, indicating a tendency to efficiently obtain ozone water with a high ozone concentration. Furthermore, in Tables 3 to 5, the results of the corrosive gas supply device test numbers 34 to 46, test numbers 50 to 53, and test numbers 65 to 70 show that the liquid flow rate [ml / (cm ２ It was shown that when the ratio of the corrosive gas pressure [kPaG] to the ozone concentration [kPaG x min] was 400 or more and the corrosive gas pressure was 1.5 MPaG or less, ozone water with a high ozone concentration tended to be obtained more efficiently.

[0086] As described above, the corrosive gas supply system has been shown to have excellent performance in supplying corrosive gases, and is therefore suitable for use as an air supply system in semiconductor manufacturing processes, wastewater treatment processes, chemical manufacturing processes, etc.

[0087] REFERENCE SIGNS LIST 1 hollow fiber membrane 2 membrane member 4 second sealing portion 5 first sealing portion 7, 7A, 7B liquid supply port 8, 8A, 8B liquid outlet 9, 9A, 9B gas supply port 11, 11A, 11B housing 12 second sleeve 13 second cap 14 first sleeve 15 first cap 19, 19A, 19B gas outlet 20 corrosive gas supply mechanism 21, 31, 41, 46 pressure adjustment valve 30 liquid supply mechanism 40 exhaust portion 45 corrosive gas solution outlet portion 50, 50A, 50B gas supply module 100 corrosive gas supply device

Claims

1. A corrosive gas supply device capable of supplying a corrosive gas to a liquid supplied to the outside or inside of a hollow fiber membrane, comprising: an air supply module; a liquid supply mechanism that supplies the liquid to the air supply module; and a corrosive gas supply mechanism that supplies the corrosive gas to the air supply module, wherein the air supply module has a housing and a plurality of hollow fiber membranes made primarily of polytetrafluoroethylene or modified polytetrafluoroethylene, wherein the hollow fiber membranes have an average outer diameter D2 of 0.60 mm or less, an average inner diameter D1 of 0.36 mm or less, and a water pressure resistance and internal burst pressure of 1.5 MPaG or more, at least the inner circumferential surface of the housing is made of a corrosion-resistant material, the internal burst pressure of the housing is 1.5 MPaG or more, and the liquid flow rate per unit membrane area of ​​the hollow fiber membranes is 0.10 [ml / (cm ２ × min)] or more 0.40 [ml / (cm ２ x minutes)].

2. Ozone gas [400 g / m3] is used as the standard corrosive gas. ３ 2. The corrosive gas supply device according to claim 1, wherein, when a pressure of the ozone gas is P [MPaG] and the liquid is pure water, the concentration of the obtained ozone water N [mg / L] satisfies the following formula: 180P + 20≦N≦250P + 39 3. The liquid flow rate per unit membrane area of ​​the hollow fiber membrane [ml / (cm ２ 3. The corrosive gas supply device according to claim 1, wherein the pressure ratio of the corrosive gas to the gas pressure [kPaG] is 400 or more, and the pressure of the corrosive gas is 1.5 MPaG or less.

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