High-purity nitrogen gas generation system

Abstract

To provide a nitrogen gas production system which, while removing water and foreign matter from compressed air, can remove oxygen in the compressed air by chemical reaction with hydrogen performed via a catalyst, producing high-purity nitrogen gas.SOLUTION: A compressor, an air dryer, and an oil mist filter are provided in a preceding stage of an H2 converter. An air tank is provided in a subsequent stage of the H2 converter. The H2 converter to which a hydrogen cylinder with hydrogen gas being reserved therein is connected includes: a drainage port through which water produced by reaction of hydrogen in the hydrogen gas with oxygen in compressed air is discharged; an air discharge port through which high-purity nitrogen gas having a nitrogen concentration increased due to reaction of the oxygen is discharged; and a catalyst which is charged in the H2 converter so as to increase reactivity between the hydrogen and the oxygen. The H2 converter further includes a hydrogen discharge tube extending on an upper side of the H2 converter to discharge excess hydrogen remaining without reacting with oxygen.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a system for producing high-purity nitrogen gas, and more particularly to a system for producing high-purity nitrogen by flowing compressed air pressure and hydrogen into an H2 converter. [Background technology]

[0002] Conventionally, methods for extracting only nitrogen from compressed air have included the PSA method, in which mixed gas is supplied to an adsorption tower filled with adsorbents such as zeolite or activated carbon, and the target components are separated and purified by repeatedly pressurizing (adsorption process) and depressurizing (desorption process), or the hollow fiber membrane method, in which compressed air is sent through a gas separation membrane (hollow fiber membrane) and nitrogen-rich gas, mainly consisting of nitrogen that did not pass through the membrane, is extracted.

[0003] However, the PSA method has problems such as the equipment itself being very expensive and requiring a large installation space, and the hollow fiber membrane method also has problems such as low production efficiency relative to the amount of air used and low purity of the nitrogen produced (90 to 99%). Therefore, there was a need for a system that could efficiently generate high-purity nitrogen.

[0004] To solve the above problem, a technical proposal has been made as described in Patent Document 1. That is, Patent Document 1 proposes a technical proposal to generate high-purity nitrogen gas from which trace amounts of oxygen have been removed by arranging a deoxygenation device downstream of a hollow fiber membrane. However, the technical proposal described in Patent Document 1 does not include a moisture removal means, which causes moisture to adhere to the oxygen absorber cartridge provided in the oxygen removal device, accelerating deterioration.

[0005] Similarly, in order to solve the above problem, the present applicant has developed a technology in which oxygen is removed from compressed air from which foreign matter has been removed by providing an air dryer and a hollow fiber membrane after the filter, and has proposed the technology described in Patent Document 2. However, although the proposal in Patent Document 2 is useful in reducing the effort, space, and cost required for generating nitrogen gas, the nitrogen gas produced using hollow fiber membranes is of low purity, and the above-mentioned problems are not yet solved.

[0006] The applicant focused on the phenomenon in which the nitrogen concentration is increased by removing oxygen from the nitrogen gas generated in the conventional nitrogen gas generation systems described above, and came up with the idea of ​​generating high-purity nitrogen gas from compressed air. He developed a nitrogen gas generation system in which compressed air is introduced into an H2 converter and high-purity nitrogen gas is generated through a chemical reaction between the oxygen and hydrogen in the compressed air, leading to the proposal of the "high-purity nitrogen generation system" of the present invention. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-308379 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-300710 Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above problems, an object of the present invention is to provide a nitrogen gas generation system capable of generating high-purity nitrogen gas by removing oxygen from compressed air through a chemical reaction with hydrogen. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides a high-purity nitrogen gas generation system that generates high-purity nitrogen gas from compressed air, and includes a compressor, an air dryer, and an oil mist filter disposed downstream of the air dryer, all located upstream of an H2 converter, and an air tank located downstream of the H2 converter. The H2 converter is connected to a hydrogen cylinder in which hydrogen gas is stored, and includes a hydrogen inlet through which hydrogen gas is introduced, a compressed air inlet through which compressed air sent from the oil mist filter is introduced, a drain outlet through which water produced by the reaction of hydrogen in the hydrogen gas with oxygen in the compressed air is discharged, an exhaust outlet through which high-purity nitrogen gas having an increased nitrogen concentration due to the reaction of the oxygen is discharged, and a catalyst that is filled inside the H2 converter and that increases the reactivity between hydrogen and oxygen. A hydrogen exhaust pipe extends above the H2 converter to discharge excess hydrogen that remains unreacted with oxygen.

[0010] The present invention also employs a means in which an air dryer is provided downstream of the H2 converter.

[0011] Furthermore, the present invention employs a means in which a hollow fiber membrane module is provided between the oil mist filter and the H2 converter.

[0012] Furthermore, the present invention employs a means in which the air tank is provided with a pressure switch that detects the pressure inside the air tank, and the inflow amounts of compressed air and hydrogen are controlled according to the pressure inside the air tank.

[0013] Furthermore, the present invention employs a means in which the catalyst is packed in layers.

[0014] Furthermore, the present invention employs a measure in which the amount of hydrogen flowing into the H2 converter is at least twice the amount of oxygen flowing into the H2 converter. [Effects of the Invention]

[0015] According to the high-purity nitrogen generation system of the present invention, a compressor, an air dryer, and an oil mist filter arranged after the air dryer are provided before the H2 converter, so that the generated compressed air flows into the H2 converter with moisture and oil removed, thereby achieving the excellent effect of generating clean, high-purity nitrogen gas. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is an explanatory diagram showing an embodiment of a high-purity nitrogen generation system according to the present invention. [Figure 2] FIG. 2 is an explanatory diagram showing another embodiment of the high-purity nitrogen generation system according to the present invention. [Figure 3] FIG. 2 is an explanatory diagram showing another embodiment of the high-purity nitrogen generation system according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] The most notable feature of the high-purity nitrogen gas generation system 1 according to the present invention is that an air dryer 3 and an oil mist filter 4 are disposed in front of the H2 converter 10. Hereinafter, an embodiment of a high-purity nitrogen gas generating system 1 according to the present invention will be described with reference to the drawings.

[0018] The high-purity nitrogen gas generation system 1 according to the present invention is not limited to the embodiments described below, but can be modified as appropriate within the scope of the technical concept of the present invention, i.e., within the scope of shapes, dimensions, materials, etc. that can achieve the same functional effects.

[0019] Fig. 1 is an explanatory diagram showing an embodiment of a high-purity nitrogen gas generation system 1 according to the present invention. Fig. 2 is an explanatory diagram showing another embodiment of a high-purity nitrogen gas generation system 1 according to the present invention, more specifically, an explanatory diagram showing an embodiment in which a hollow fiber membrane module 20 is provided between an oil mist filter 4 and an H2 converter 10. Fig. 3 is an explanatory diagram showing another embodiment of a high-purity nitrogen gas generation system 1 according to the present invention, more specifically, an explanatory diagram showing an embodiment in which an air dryer 3B is provided downstream of the H2 converter 10. The high-purity nitrogen gas generation system 1 of the present invention comprises a compressor 2, an air dryer 3, and an oil mist filter 4 (hereinafter sometimes referred to as various devices) arranged in this order before an H2 converter 10 to which a hydrogen cylinder 6 is connected, and an air tank 5 arranged after the H2 converter 10. The compressed air generated by the compressor 2 is dried by removing drain in the air dryer 3, and then oil is removed by the oil mist filter 4 before flowing into the H2 converter 10. A chemical reaction occurs within the H2 converter 10 via a catalyst 15, converting the oxygen in the compressed air and the hydrogen that has flowed in from the hydrogen cylinder 6 into water, thereby removing the oxygen. The oxygen is then stored in the air tank 5 as high-purity nitrogen gas and is then supplied to the nitrogen-using equipment in the downstream stage.

[0020] In order to send the compressed air generated by the compressor 2 to the downstream, a pipe A is provided connecting the various devices provided from the compressor 2 to the H2 converter 10, a pipe B is provided connecting the hydrogen cylinder 6 and the H2 converter 10, and a pipe C is provided connecting the pipe B to the downstream equipment using nitrogen gas via the air tank 5. Furthermore, there are no particular restrictions on the diameters of pipes A, B, and C. However, by making the diameter of pipe A connecting various devices the same, it is possible to reduce the pressure loss of the compressed air flowing through pipe A. Pipes A, B, and C are constructed using conventionally known technology. However, pipes B in particular are constructed from materials that take into consideration hydrogen corrosion and hydrogen embrittlement, which are caused by hydrogen atoms penetrating into steel and accelerating deterioration, such as carbon steel.

[0021] The compressor 2 is a device that draws in atmospheric air from an air intake port, increases the pressure to a predetermined pressure (for example, 0.7 MPa), and compresses it to generate compressed air. There are various types of compressors 2, such as reciprocating, rotary, and centrifugal types, depending on the structure for generating compressed air. There are also types such as oil-lubricated and oil-free types, depending on whether lubricating oil is used. There are no particular limitations on the type of compressor 2 used in the present invention, and any type or structure can be used. The air compressed by the compressor 2 contains not only water vapor and dust but also oil floating in the vicinity, and this oil is sent together with the generated compressed air in the form of an oil mist. Also, if the compressor 2 is an oil-lubricated compressor, the lubricating oil used there will become oil in the form of an oil mist and be sent together with the generated compressed air. The compressed air generated by the compressor 2 is sent via a pipe A to an air dryer 3 at a downstream stage.

[0022] The air dryer 3 is a device for drying the compressed air sent from the compressor 2 and removing moisture. The amount of moisture in the air that makes up the compressed air varies depending on the surrounding environment, such as the location and operating season of the compressor 2. Furthermore, carbon dioxide and oxygen dissolve in the moisture under high pressure. Therefore, the amount of moisture contained in the compressed air generated by atmospheric compression by the compressor 2 varies depending on the surrounding environment, just like the amount of moisture in the air, and the amount of gas that dissolves in the moisture also varies depending on the amount of moisture, so the air composition ratio of the compressed air sent to the H2 converter 10 is not stable. If the compressed air generated by the compressor 2 is allowed to flow directly into the H2 converter 10, the amount of oxygen and hydrogen flowing into the H2 converter 10 will vary depending on the amount of moisture contained therein, making it difficult to balance the amount of oxygen in the compressed air used in the chemical reaction with the amount of hydrogen flowing in from the hydrogen cylinder 6. Therefore, by arranging an air dryer 3 downstream of the compressor 2 and separating and removing the moisture in the compressed air, it becomes possible to stabilize the air composition ratio of the compressed air sent to the H2 converter 10, making it easier to adjust the balance between the amount of oxygen in the compressed air used for the chemical reaction and the amount of hydrogen flowing in from the hydrogen cylinder 6. The air dryer 3 is available in various types, such as a refrigeration type, hollow fiber membrane type, and adsorption type, depending on the method of removing moisture. The air dryer 3 used in the present invention may be any of the refrigeration type, hollow fiber membrane type, and adsorption type, and is not particularly limited, but the most commonly used is the refrigeration type air dryer 3. The refrigeration type air dryer is a device that uses the latent heat of evaporation of a refrigerant to cool compressed air and condense and remove the contained moisture, and is therefore preferable because it can be introduced relatively inexpensively. The dried compressed air from which the moisture has been removed is sent to the oil mist filter 4 installed downstream, where the oil is removed. In addition, in the process of condensing and removing the moisture contained in the compressed air, the refrigerated air dryer generates drain inside the air dryer 3 due to a decrease in the amount of saturated water vapor caused by cooling, so a drain pipe is provided to discharge the drain, and the drain that flows into the drain pipe is discharged to the outside by a drain trap. The compressed air from which moisture has been removed by the air dryer 3 is sent to the oil mist filter 4 in the subsequent stage.

[0023] The oil mist filter 4 is a filter for removing oil in the form of oil mist contained in the compressed air sent from the air dryer 3. When oil contained in the compressed air flows into the high-temperature H2 converter 10, it is thermally decomposed, and the carbon component (C) contained in the oil combines with the oxygen (O2) contained in the oil and compressed air to produce carbon dioxide (CO2). For this reason, an oil mist filter 4 is provided to separate and remove oil contained in the compressed air before it flows into the H2 converter 10. The oil mist filter 4 has a filter structure that removes oil as compressed air passes through it, and can be made using conventionally known technology, such as by providing an oil mist element in the compressed air flow path, and the material of the filter part that removes oil mist is a fine-mesh material such as nonwoven fabric or polyolefin. The compressed air from which oil has been removed by the oil mist filter 4 is sent to the H2 converter 10 at the downstream side.

[0024] The hydrogen cylinder 6 is a cylinder that stores hydrogen to be sent to the H2 converter 10 via a pipe B. The specific structure of the hydrogen cylinder 6 may be any known technology. The capacity of the hydrogen cylinder 6 to store hydrogen is determined by the user, taking into consideration the amount of compressed air produced by the compressor 2, the operating time, etc. 1 and 2, it is preferable that multiple hydrogen cylinders 6 are connected to the pipe B. By adopting such an arrangement, even if the required amount of hydrogen increases due to long-term operation, smooth hydrogen supply is possible by switching the supply cylinders.

[0025] The H2 converter 10 is a device that sends high-purity nitrogen produced by a chemical reaction between compressed air sent from the compressor 2 and hydrogen sent from the hydrogen cylinder 6 via a catalyst 15 to the downstream air tank 5, and simultaneously discharges the water produced. The H2 converter 10 is a cylindrical body with a hollow portion, and is provided with a compressed air inlet 12 connected to pipe A and through which compressed air flows in, a hydrogen inlet 11 connected to pipe B and through which hydrogen flows in, and an exhaust port 14 connected to pipe C and through which high-purity nitrogen is sent to the air tank 5. The bottom of the H2 converter 10 is provided with a drain port 13 through which water produced by a chemical reaction is discharged to the outside, and the top of the H2 converter 10 is connected to a hydrogen discharge pipe 16 through which hydrogen that remains without undergoing a chemical reaction can be discharged. By providing the compressor 2, the air dryer 3, and the oil mist filter 4 disposed after the air dryer 3 in the upstream of the H2 converter 10, the compressed air that is generated flows into the H2 converter 10 with moisture and oil removed, which has the excellent effect of producing clean, high-purity nitrogen gas.

[0026] The catalyst 15 is filled in the H2 converter 10 in order to increase the reactivity between the oxygen in the compressed air generated by the compressor 2 and the hydrogen flowing in from the hydrogen cylinder 6. The catalyst 15 is made of a metal material such as copper, platinum, palladium, nickel, cobalt, zirconium, or an alloy of these metals. To increase the surface area that oxygen and hydrogen come into contact with the catalyst 15, a mesh-like material is layered and filled inside the H2 converter 10. Although not shown, the H2 converter 10 is provided with heating means for heating the catalyst 15 (to about 200°C if copper is used as the catalyst). By packing the catalyst 15 in layers, oxygen and hydrogen flowing into the H2 converter 10 can easily come into contact with the catalyst, which has the excellent effect of further promoting the chemical reaction. As a packing mode of the catalyst 15, in addition to the above-mentioned layered mode, a mode in which metal material is made into fine particles and supported on alumina (aluminum oxide) or the like is also suitable.

[0027] The chemical reaction that takes place in the H2 converter 10 involves the reaction of oxygen (O2) in the compressed air with hydrogen (H2) flowing in from the hydrogen tank, via a catalyst, to produce water (H2O), and two hydrogen molecules are required for one oxygen molecule. Therefore, in order to react all of the oxygen in the compressed air into water, it is necessary to introduce at least twice the amount of hydrogen as the amount of oxygen flowing into the H2 converter 10. By making the amount of hydrogen flowing into the H2 converter 10 more than twice the amount of oxygen flowing into the H2 converter 10, an amount of hydrogen greater than that used in the chemical reaction with the oxygen in the compressed air flows in, increasing the concentration of nitrogen sent to the downstream stage of the H2 converter 10 and contributing to the provision of nitrogen gas of higher purity. Furthermore, since the oxygen content in the atmospheric composition is approximately 21%, it is possible to set the amount of hydrogen flowing into the H2 converter 10 to 42% or more of the amount of compressed air produced by the compressor 2.

[0028] The side of the H2 converter 10 is provided with a hydrogen inlet 11 that introduces hydrogen sent from the hydrogen cylinder 6 into the H2 converter 10, and a compressed air inlet 12 that introduces compressed air sent from the oil mist filter 4 into the H2 converter 10. The hydrogen inlet 11 and the compressed air inlet 12 are provided on one side of the H2 converter 10. In this case, by providing the hydrogen inlet 11 below the compressed air inlet 12 as shown in Figures 1 and 2, the compressed air that has flowed into the H2 converter 10 can come into contact with hydrogen, which is lighter than the compressed air, efficiently, and a chemical reaction can be sufficiently induced.

[0029] The bottom of the H2 converter 10 is provided with a drain port 13 for discharging water produced by a chemical reaction that takes place within the H2 converter 10 to the outside. The drain outlet 13 is provided at the bottom of the H2 converter 10 so that water generated by the chemical reaction can be discharged even if it hangs down due to gravity and accumulates at the bottom of the H2 converter 10. When providing the drain outlet 13, the bottom of the H2 converter 10 may be formed in a shape that is inclined toward the drain outlet 13 (funnel-shaped) as a structure that allows water to be efficiently discharged. In addition, when water is discharged to the outside through the drain port 13, a drain trap and a valve are provided so that the compressed air and nitrogen gas inside the H2 converter 10 are not discharged to the outside.

[0030] A hydrogen exhaust pipe 16 is connected to the top surface of the H2 converter 10 to discharge to the outside the hydrogen that has flowed in from the hydrogen cylinder 6 and has not undergone a chemical reaction with oxygen (hereinafter referred to as "excess hydrogen"). The hydrogen discharge pipe 16 is a pipe whose base end is connected to the top surface of the H2 converter 10 and whose other end discharges excess hydrogen that has accumulated above the H2 converter 10 to the outside. The hydrogen used in the chemical reaction that takes place in the H2 converter 10 is basically hydrogen that flows in from the hydrogen cylinder 6, and taking into account the reaction with oxygen in the compressed air, an amount more than twice the expected amount of oxygen flows into the H2 converter 10. However, the hydrogen used in the chemical reaction that takes place in the H2 converter 10 naturally also includes the hydrogen that was originally contained in the compressed air. Therefore, not all of the hydrogen that flows in from the hydrogen cylinder 6 is used in the chemical reaction, and some of the hydrogen (excess hydrogen) is lighter than the other gases and therefore accumulates in the upper part of the H2 converter 10. For this reason, the base end of a hydrogen discharge pipe 16 that can discharge excess hydrogen to the outside is connected to the top part of the H2 converter 10 to prevent the excess hydrogen from mixing with the nitrogen gas generated after the chemical reaction.

[0031] The exhaust port 14 is for connecting to a pipe C so that nitrogen gas generated by a chemical reaction that takes place in the H2 converter 10 can be sent to the air tank 5 at the downstream side. 1 and 2, the exhaust port 14 is provided on the side of the H2 converter 10, but by providing the exhaust port 14 on the side opposite to the side provided with the hydrogen inlet 11 and compressed air inlet 12, it is possible to lengthen the flow path from the inflow of compressed air to the discharge, and nitrogen gas that has undergone a sufficient chemical reaction can be sent to the subsequent stage. In addition, by providing the exhaust port 14 approximately near the center of the side of the H2 converter 10, it contributes to efficient air supply without discharging excess hydrogen that accumulates above or water that accumulates below.

[0032] The air tank 5 is a tank for storing nitrogen gas sent from the H2 converter 10. The air tank 5 is a container for temporarily storing in its hollow space the compressed air (nitrogen gas) from which oxygen has been removed by a chemical reaction inside the H2 converter 10, and is arranged downstream of the H2 converter 10 via piping C. After storing the incoming nitrogen gas, it sends it to downstream equipment at a constant pressure. The provision of such an air tank 5 helps to suppress the water hammer effect of the fluid (compressed air and nitrogen gas) when the air compressor is started or stopped, thereby reducing the load on downstream equipment.

[0033] The nitrogen gas stored in the air tank 5 is used as appropriate depending on the usage conditions of the nitrogen gas-using equipment. However, if the amount of nitrogen gas used is less than the amount of nitrogen gas flowing in, there is a risk that the nitrogen gas will continue to be stored in the air tank 5 and exceed the capacity of the air tank 5. For this reason, the air tank 5 is provided with a pressure switch 21, as shown in Figures 1 and 2, which detects and controls the pressure value within the air tank 5. The pressure switch 21 is connected via a control line to a drive switch 22 that controls the operation of the compressor 2 and a regulator valve 23 that controls the flow rate of the hydrogen cylinder 6, and controls the operation of the drive switch 22 and regulator valve 23 based on the pressure detected in the air tank 5. The pressure values ​​(upper limit, lower limit, maximum value, etc.) that serve as the basis for the control operation by the pressure switch 21 are determined by the user based on the allowable pressure value of the air tank 5. For example, when the pressure switch 21 detects a pressure value equal to or greater than the upper limit, the pressure switch 21 transmits an output stop signal (OFF), and the drive switch 22, which receives the signal via a control line, stops the compressor 2, while the regulating valve 23 closes the flow path of the pipe C, thereby stopping the inflow of hydrogen and temporarily stopping the inflow of compressed air and hydrogen into the H2 converter 10 and the inflow of nitrogen gas into the air tank 5. Furthermore, when the pressure value detected by the pressure switch 21 falls below the lower limit during the stopped state, the pressure switch 21 transmits an output return signal (ON), and the drive switch 22 restarts the compressor 2, while the regulating valve 23 opens the flow path of the pipe C, thereby returning the inflow rates into the H2 converter 10 and the air tank 5 to normal levels, thereby performing control such as this. The air tank 5 is equipped with a pressure switch 21 that detects the pressure inside the air tank 5, and the amount of compressed air and hydrogen that flows in is controlled according to the pressure inside the air tank 5, making it possible to prevent damage to the air tank 5 due to excessive pressure.

[0034] The drive switch 22 is a switch that is provided in the compressor 2 to change the drive state of the compressor 2, and is connected to the pressure switch 21 via a control line. The drive switch 22 starts and stops the compressor 2 in response to a signal from the pressure switch 21, and adjusts the amount of compressed air sent to the H2 converter 10 via various devices. The adjusting valve 23 is a valve that is provided in the pipe B to adjust the amount of hydrogen sent from the hydrogen cylinder 6, and is connected to the pressure switch 21 via a control line. The adjusting valve 23 opens or closes the flow path of the pipe B in response to a signal from the pressure switch 21 to adjust the amount of hydrogen flowing into the H2 converter 10. The drive switch 22 and the regulating valve 23 are controlled by the ON / OFF signal from the pressure switch 21, thereby adjusting the amount of compressed air and hydrogen flowing into the H2 converter 10 and adjusting the pressure in the air tank 5 located downstream.

[0035] Water generated by a chemical reaction in the H2 converter 10 may turn into water vapor and become mixed into the nitrogen gas sent to the air tank 5. For this reason, as shown in Figure 3, an air dryer 3B is provided downstream of the H2 converter 10. The air dryer 3B is not particularly limited and may be of any of a refrigeration type, hollow fiber membrane type, or adsorption type, similar to the above-described air dryer 3. The air dryer 3B is also provided with a drain pipe for discharging the separated and removed water (drain), and the drain that flows into the drain pipe is discharged to the outside by a drain trap. By providing an air dryer 3B downstream of the H2 converter 10, water vapor mixed in the nitrogen gas can be separated and removed, allowing highly pure and dry nitrogen gas to flow into the air tank 5.

[0036] As shown in FIG. 2, a mode in which a hollow fiber membrane module 20 is provided between the oil mist filter 4 and the H2 converter 10 is also suitable. The hollow fiber membrane module 20 is a module filled with hollow fiber membranes formed by bundling a large number of straw-shaped hollow fibers, and the hollow fiber membranes are made of resins such as polyester, polyolefin, and polypropylene. By passing the compressed air sent from the oil mist filter 4 through this hollow fiber membrane module 20, the difference in membrane permeation speed inherent to each gas, such as nitrogen and oxygen, that makes up the compressed air can be utilized to separate gases other than nitrogen, such as oxygen, hydrogen, and helium, thereby making it possible to increase the nitrogen purity in the compressed air sent to the downstream H2 converter 10. By providing the hollow fiber membrane module 20 between the oil mist filter 4 and the H2 converter 10, clean compressed air from which moisture and oil have been removed flows into the hollow fiber membrane module 20, reducing deterioration, and it is also possible to send nitrogen-rich gas from which gases such as oxygen have been removed in advance to the H2 converter 10.

[0037] The main operations and actions of the high-purity nitrogen gas generating system 1 comprising the above components will be described with reference to FIG. The high-purity nitrogen gas generation system 1 comprises a compressor 2, an air dryer 3, an oil mist filter 4, an H2 converter 10 connected to a hydrogen cylinder 6, and an air tank 5 equipped with a pressure switch 21. First, compressed air is generated by compressor 2 and flows into air dryer 3. The compressed air, from which drainage has been separated and removed by being cooled and dried in air dryer 3, flows into oil mist filter 4 disposed downstream. The clean compressed air, from which oil mist has been separated and removed in oil mist filter 4, flows into H2 converter 10 via compressed air inlet 12. Similarly to the compressed air, hydrogen flows into H2 converter 10 from hydrogen cylinder 6 via hydrogen inlet 11. The compressed air that flows into the H2 converter 10 comes into contact with the catalyst 15 filled inside the H2 converter 10, whereby the oxygen in the compressed air and the hydrogen that flows in from the hydrogen cylinder 6 undergo a chemical reaction and are converted into water. This chemical reaction separates the oxygen from the compressed air, turning it into high-purity nitrogen gas. The nitrogen gas in the H2 converter 10 flows through the exhaust port 14 into the air tank 5 located downstream, where it is temporarily stored, and then used by nitrogen gas-using equipment connected downstream of the air tank 5. As described above, by providing the oil mist filter 4 upstream of the air dryer 3, it is possible to prevent problems such as moisture adhering to the oil mist filter 4 and reducing its ability to remove oil. Furthermore, by providing the air dryer 3 and oil mist filter 4 upstream of the H2 converter 10, it is also possible to prevent problems such as moisture and oil adhering to the catalyst packed inside the H2 converter 10 and reducing its catalytic function, or carbon dioxide being generated due to the decomposition of oil at high temperatures.

[0038] Next, the main operation and function of an embodiment in which the hollow fiber membrane module 20 is provided between the oil mist filter 4 and the H2 converter 10 will be described with reference to Figure 2. Note that parts that are the same as those described above will be omitted. The compressed air generated by the compressor 2 passes through an air dryer 3 and an oil mist filter 4, whereby moisture and oil are removed to produce clean compressed air. The clean compressed air sent from the oil mist filter 4 flows into the hollow fiber membrane module 20, where oxygen, argon, and other gases with fast permeation speeds are discharged to the outside, while nitrogen gas, which is mainly composed of nitrogen and has a slower permeation speed, is sent to the H2 converter 10 connected in the downstream stage. The nitrogen gas that flows into the H2 converter 10 contains oxygen that was not completely discharged by the hollow fiber membrane module 20, but this oxygen is converted into water by a chemical reaction within the H2 converter 10 and discharged, and is then sent to the downstream air tank 5 as high-purity nitrogen gas. As described above, by disposing the hollow fiber membrane module 20 between the oil mist filter 4 and the H2 converter 10, it is possible to reduce the content of gases other than nitrogen in the compressed air flowing into the H2 converter 10 in advance, and it is possible to send nitrogen gas that has been made even more highly pure by a chemical reaction within the H2 converter 10 to downstream nitrogen-using equipment.

[0039] Furthermore, the main operations and effects of an embodiment in which an air dryer 3B is provided in the subsequent stage of the H2 converter 10 will be described with reference to Fig. 3. Note that parts that are the same as those described above will be omitted. The compressed air generated by the compressor 2 passes through an air dryer 3A and an oil mist filter 4, whereby moisture and oil are removed, resulting in clean compressed air, which is then sent to an H2 converter 10 provided downstream of the oil mist filter 4. The compressed gas that flows into the H2 converter 10 undergoes a chemical reaction with hydrogen that flows in from the hydrogen cylinder 6 via a catalyst filled in the H2 converter 10, causing the oxygen contained in the compressed air to change into water, which is then discharged, and the resulting gas is sent to the downstream air dryer 3B as nitrogen gas. At this time, the water generated by the chemical reaction is blown up by the pressure of the nitrogen gas and mixed into the nitrogen gas. The nitrogen gas that flows into the air dryer 3B is cooled and dried, and the moisture that has been mixed in inside the H2 converter 10 is separated and removed, and the high-purity nitrogen gas is sent to the air tank 5 in the downstream stage. As described above, by providing the air dryer 3B downstream of the H2 converter 10, it becomes possible to separate and remove moisture that has become mixed in the H2 converter 10 in advance, and it becomes possible to send dried, highly purified nitrogen gas to downstream nitrogen-using equipment.

[0040] The basic configuration and operation of the high-purity nitrogen gas generation system 1 according to the present invention have been described above, but the present invention is not limited to the configuration shown in the above embodiment or the drawings. For example, a suitable configuration would include a flow meter that detects the flow rate of compressed air generated by the compressor 2 and a control unit that controls the amount of hydrogen sent from the hydrogen cylinder 6 based on that flow rate. By adopting such a configuration, it is possible to flow the same amount of hydrogen as used in the chemical reaction into the H2 converter 10, thereby reducing the amount of hydrogen that is surplus to the chemical reaction.

[0041] As described above, the high-purity nitrogen gas generation system 1 according to the present invention is configured such that the air dryer 3 and oil mist filter 4 are disposed upstream of the H2 converter 10, thereby allowing compressed air from which moisture and oil have been removed to flow into the H2 converter 10. At the same time, a chemical reaction occurs within the H2 converter 10, converting the oxygen in the compressed air into water, turning the air into high-purity nitrogen gas, which is then sent to the downstream air tank 5 and nitrogen-gas-using equipment. [Industrial Applicability]

[0042] The present invention can be applied to any field that requires nitrogen as an inert gas, such as food processing, electronic component manufacturing, car body painting, etc. Therefore, it is believed that the "high-purity nitrogen gas generation system" according to the present invention has great industrial applicability. [Explanation of symbols]

[0043] 1. High-purity nitrogen gas generation system 2 Compressor 3 Air dryer 4 Oil mist filter 5. Air Tank 6 Hydrogen Cylinders 10 H2 Converter 11 Hydrogen inlet 12 Compressed air inlet 13 Drain 14 Exhaust port 15 Catalyst 16 Hydrogen exhaust pipe 20 Hollow fiber membrane module 21 Pressure switch 22 Drive switch 23 Regulating valve

Claims

1. A high-purity nitrogen gas generation system for generating high-purity nitrogen gas from compressed air, comprising: A compressor, an air dryer, and an oil mist filter disposed downstream of the air dryer are ２ The H ２ An air tank is provided after the converter, H ２ The converter is connected to a hydrogen cylinder storing hydrogen gas and includes a hydrogen inlet port through which hydrogen gas is introduced, a compressed air inlet port through which compressed air sent from the oil mist filter is introduced, a drain port through which water generated by the reaction between hydrogen in the hydrogen gas and oxygen in the compressed air is discharged, an exhaust port through which high-purity nitrogen gas with an increased nitrogen concentration due to the reaction with oxygen is discharged, and a H ２ a catalyst filled inside the converter to increase the reactivity of hydrogen and oxygen; The hydrogen inlet is provided at a position lower than the compressed air inlet, H ２ A hydrogen exhaust pipe extends from the upper side of the converter to discharge excess hydrogen that has not reacted with oxygen. A pressure switch is provided to detect the pressure inside the air tank and to control the compressor and the flow rate of the hydrogen cylinder based on the detected pressure value. The pressure switch is connected via a control line to a drive switch that controls the drive of the compressor and to a regulating valve that controls the flow rate of the hydrogen cylinder. A high-purity nitrogen gas generation system characterized by controlling the inflow of compressed air and hydrogen by controlling a drive switch and an adjustment valve according to the pressure inside the air tank.

2. The H ２ 2. The high-purity nitrogen gas generating system according to claim 1, further comprising an air dryer provided downstream of the converter.

3. The oil mist filter and H ２ A hollow fiber membrane module is provided between the converter and the The high-purity nitrogen gas generation system according to claim 1, characterized in that compressed air having an increased nitrogen concentration is sent to the H2 converter by passing the compressed air sent from the oil mist filter through the hollow fiber membrane module.

4. 2. The high-purity nitrogen gas generating system according to claim 1, wherein the catalyst is packed in a layered manner.

5. The H ２ The amount of hydrogen flowing into the converter is ２ 2. The high-purity nitrogen gas generating system according to claim 1, wherein the amount of oxygen flowing into the converter is at least twice as large as the amount of oxygen flowing into the converter.

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