System for inspecting membrane module and method for inspecting membrane module

Abstract

Provided is an inspection system with which it is possible to carry out a performance evaluation and a leak test without removing a separation membrane element. The present invention comprises: a separation membrane element installed in a membrane module; a supply source for supplying, to the membrane module, a mixed gas in which the mixing ratio of a non-condensable gas and a condensable gas is adjusted; a first determination unit provided in the middle of piping between the supply source and a supply port of the membrane module; a joint attached to a permeation-side outlet of the separation membrane element filled into the membrane module; an exhaust port for discarding unnecessary gas; a mass flow meter for determining the flow rate of the non-condensable gas, the mass flow meter being provided in the middle of the piping between the joint and the exhaust port; a second determination unit provided in the middle of the piping between the joint and the exhaust port; and a measurement unit for carrying out the determination performed by the first determination unit and the second determination unit and the determination performed by the mass flow meter.

Description

Membrane module inspection system and membrane module inspection method

[0001] The present invention relates to an inspection system and inspection method that can easily perform inspections within a multi-tube separation membrane module (hereinafter referred to as a membrane module).

[0002] Conventionally, nanoporous ceramic separation membranes, such as zeolite-based and silica-based separation membranes, have a tubular porous ceramic support and a porous separation membrane made of a nanoporous material provided on the outer surface of the support. To separate specific components from fluids such as solutions or gas mixtures, methods are known that involve bringing the fluid of the solution into contact with one side (outer surface) of the membrane and reducing the pressure on the other side (inner surface) to vaporize and separate the specific components; vaporizing the solution and bringing it into contact with the separation membrane in a gaseous state, then reducing the pressure on the non-contact side to separate the specific components; or bringing a pressurized gas mixture into contact with the separation membrane to separate specific components. In addition, membrane modules in which multiple separation membrane elements are installed in a housing are sometimes used. In such cases, it is necessary to inspect whether the fluid to be processed leaks to the secondary side (permeate side) from defective parts or faulty seals in the membrane.

[0003] One leak testing method has involved applying gas pressure to measure the amount of gas leakage. For example, in Patent Document 1, liquid is supplied into the membrane module and then discharged to wet the separation membrane element (tubular separation membrane), and then gas pressure is applied to the supply side to test for leaks by measuring the amount of gas that flows out to the permeate side. However, this method only detects leaks in the entire installed membrane and does not allow for the evaluation of leaks in individual membranes or the permeability of the membranes themselves. In other words, since a large number of separation membrane elements are packed in the module, it has been difficult to individually evaluate the performance of these membranes or perform leak tests on them.

[0004] In particular, when evaluating the permeability of a membrane module after use, it was necessary to remove all the separation membrane elements from the module and evaluate them individually. This process involved the time-consuming steps of removing, evaluating, and then reinstalling the separation membrane elements, requiring considerable effort.

[0005] Furthermore, while there are measuring devices for separation membrane elements based on nano-palm porometry, a pore size measurement technique, as described in Patent Document 2, these devices do not measure the permeability of condensable gases, making it impossible to evaluate the permeability of separation membranes. In addition, nano-palm porometry uses data on the permeability (also called transmittance) of non-condensable gases measured under various humidity conditions for analysis, which means that it takes a long time to obtain measurement results, making it unsuitable for a process that evaluates all of the numerous separation membrane elements within a membrane module.

[0006] In this situation, there has been a strong need for a method to quickly measure the leak and permeability of each separation membrane element while a multi-tube separation membrane module is installed. The present invention addresses this need and provides a novel method that allows for simultaneous performance evaluation and leak testing without removing the separation membrane elements within the membrane module.

[0007] Japanese Patent Publication No. 2021-023898 Japanese Patent Publication No. 2019-203825

[0008] When performing performance evaluation and leak testing on individual separation membrane elements within a membrane module, conventional techniques require removing the separation membrane elements from the module and evaluating them individually, which is time-consuming and labor-intensive. Furthermore, there is a risk of damage during the membrane removal process. Additionally, conventional methods only allow leak testing of the entire membrane, making it difficult to identify leaks or performance degradation in specific membranes.

[0009] To achieve the above objective, the first form of the inspection system is characterized by comprising: a separation membrane element installed in a membrane module; a supply source for supplying a mixed gas to the membrane module with an adjusted mixing ratio of non-condensable gas and condensable gas; a first measuring unit installed in the middle of the piping between the supply source and the supply port of the membrane module; a fitting attached to the permeate-side outlet of the separation membrane element filled in the membrane module; an exhaust port for discarding unwanted gas; a mass flow meter installed in the middle of the piping between the fitting and the exhaust port for measuring the flow rate of non-condensable gas; a second measuring unit installed in the middle of the piping between the fitting and the exhaust port; and a measurement unit that performs measurements in the first and second measuring units and measurements in the mass flow meter.

[0010] The second form of the inspection system is characterized in that multiple separation membrane elements are installed in a membrane module, and when measuring with the first measurement unit and the second measurement unit, and when measuring with the mass flow meter, a fitting is attached to the permeate side outlet of each separation membrane element.

[0011] The third form of the inspection system is characterized in that, when the separation membrane element is hydrophilic, nitrogen is used as the non-condensable gas and water as the condensable gas, and a hygrometer, thermometer, and pressure gauge are used as the first and second measurement units. The fourth form of the inspection system is characterized in that, when the separation membrane element is hydrophobic, nitrogen is used as the non-condensable gas and alcohol is used as the condensable gas, and an alcohol meter, thermometer, and pressure gauge are used as the first and second measurement units.

[0012] Furthermore, the inspection method for a membrane module using the inspection system of the embodiment is characterized by performing the following steps: (a) supplying a mixed gas into the membrane module from a supply source of mixed gas with an adjusted mixing ratio of non-condensable gas and condensable gas, and adjusting the pressure of the condensable gas in the mixed gas according to the pinhole size to be detected while monitoring with a first measuring unit installed in the middle of the piping between the supply source and the supply port of the membrane module; (b) monitoring using the first measuring unit as the supplied mixed gas passes through the separation membrane element to be inspected; (c) monitoring using a second measuring unit and a mass flow meter installed in the middle of the piping between the fitting attached to the permeate side outlet of the separation membrane element and the exhaust port; and (d) simultaneously performing a performance evaluation and leak test of the separation membrane element through a measurement unit based on the monitoring results from the first measuring unit, the second measuring unit and the mass flow meter.

[0013] The first configuration differs significantly from conventional technology in that it allows for simultaneous performance evaluation and leak testing of individual separation membrane elements within a membrane module. This inspection system enables efficient and accurate evaluation of individual separation membrane elements while they remain installed in the membrane module. This allows for rapid and accurate diagnosis of the condition of separation membrane elements while avoiding risks associated with handling membranes, resulting in more efficient maintenance and reduced costs.

[0014] In the second embodiment, when measuring with the first and second measurement units and the mass flow meter, the fittings are attached to the permeate-side outlets of each separation membrane element. Therefore, the condition of each separation membrane element can be diagnosed by attaching and replacing the fittings.

[0015] According to the third embodiment, nitrogen is used as the non-condensable gas and water as the condensable gas, and a hygrometer, thermometer, and pressure gauge are used as the first and second measurement units to inspect a hydrophilic separation membrane element. According to the fourth embodiment, nitrogen is used as the non-condensable gas and alcohol as the condensable gas, and an alcohol meter, thermometer, and pressure gauge are used as the first and second measurement units to inspect a hydrophobic separation membrane element.

[0016] Furthermore, while the inspection method for the membrane module in this embodiment is similar to nano-palm porometry, a pore size measurement technique, nano-palm porometry only measures the transmittance of non-condensable gases, whereas this embodiment can simultaneously measure the transmittance of condensable gases, such as water vapor. The novelty lies in the fact that by simultaneously measuring the water vapor transmittance and non-condensable gas transmittance of the membrane, membrane water vapor permeability and leaks can be efficiently evaluated at the same time. In addition, since the measurement is adjusted according to the pinhole size for detecting the pressure of condensable gases in the mixed gas, based on the application of the separation membrane element, inspection results can be obtained quickly. Moreover, the inspection method in this embodiment is not limited to humidity sensors and can be combined with other measurement means. For example, a configuration can be made to detect the concentration or flow rate of condensable or non-condensable components that have permeated the membrane using detection means such as infrared sensors, gas chromatographs, and mass spectrometers. By appropriately selecting or combining such detection means, the transmittance of other vapor components such as hydrocarbon solvent vapors, in addition to water vapor and alcohol vapor, can also be measured. Furthermore, if necessary, the permeated components may be collected using a low-temperature trap with liquid nitrogen or the like, and then quantitatively analyzed. This allows for flexible design of inspection conditions and detection methods according to the target gas type and vapor components, enabling highly reliable performance evaluation and leak testing of the membrane module.

[0017] This invention is expected to significantly improve the reliability and efficiency of membrane modules in many industrial fields that utilize membrane technology.

[0018] This figure schematically shows the general configuration of the main body of the inspection system and the piping system. (a) is an enlarged schematic diagram of the first part of the membrane module, and (b) is an enlarged schematic diagram of the second part. This is a schematic diagram of a piping example in the inspection system of Figure 1 where air is used as the non-condensable gas. This is a schematic diagram explaining the installation positions of measuring instruments corresponding to the configuration of the inspection system of Figure 1. This is a schematic diagram of a piping example for introducing a carrier gas in the inspection system of Figure 1. (a) is a schematic diagram and (b) is a partially enlarged schematic diagram of a piping example for introducing a carrier gas in the inspection system of Figure 1.

[0019] Performance evaluation and leak testing of nanoporous ceramic separation membranes using the inspection system of the present invention will be described with reference to the drawings, but the present invention is not limited to the disclosure of this embodiment.

[0020] Figure 1 is a schematic diagram showing the main body configuration and piping system of the inspection system 100. The inside of the membrane module 1 is sealed, and a fitting consisting of a connection adapter 6 and a permeate gas discharge pipe 7 is attached to the permeate-side outlet of the cylindrical separation membrane element 2, which is inserted horizontally into the membrane module 1. The outer cover (flange) of the membrane module 1 is removed, and the inspection system 100 of this embodiment is attached to the permeate-side outlet of the separation membrane element 2 to be inspected.

[0021] In this example, the separation membrane element 2 installed in the membrane module 1 is held inside the membrane module 1, with its permeable outlet slightly fitted to the outside of the membrane module 1. The other end of the separation membrane element 2 inside the membrane module 1 is closed by an end cap 3 to maintain airtightness inside the membrane module 1.

[0022] The membrane module 1 is connected to an inspection gas supply pipe 4 and a non-permeable gas discharge pipe 5. A mixed gas of non-condensable and condensable gases is supplied to the inspection gas supply pipe 4. Non-condensable gases include inert gases such as nitrogen, air, hydrogen, helium, and argon. Nitrogen gas is used as an example here. Condensable gases include water vapor, ethanol, and hexane. Water vapor is used as an example here.

[0023] A dry gas inlet pipe 10, connected to a nitrogen gas source 8, is connected to the inspection gas supply pipe 4, and a wet gas inlet pipe 11 is connected to the dry gas inlet pipe 10. On the nitrogen gas source 8 side of the connection point of the wet gas inlet pipe 11 in the dry gas inlet pipe 10, a regulator 9 is provided, which serves as a pressure adjustment means to maintain the dry gas inlet pipe 10, and consequently the wet gas inlet pipe 11 and the inside of the membrane module 1, at a value greater than atmospheric pressure. The pressure inside the membrane module 1 is precisely adjusted by a back pressure valve 32, which will be described later.

[0024] A mass flow controller 18 (MFC) and one solenoid valve 12 are provided in the portion of the dry gas inlet pipe 10 that runs parallel to the wet gas inlet pipe 11. A mass flow controller 19 (MFC) is provided upstream of the wet gas inlet pipe 11, and two solenoid valves 13 and 14 are provided downstream of it. These mass flow controllers 18 and 19, solenoid valves 12, 13 and 14, and a solenoid valve 16 (described later) form an adjustment means for adjusting the mixing ratio of non-condensable gas and condensable gas supplied inside the membrane module 1.

[0025] In the moist gas introduction pipe 11, the inlet pipes 24 and outlet pipes 25 of two bubblers 20 and 21 are connected to the upstream and downstream sides of each of the two solenoid valves 13 and 14, respectively, corresponding to the number of solenoid valves 13 and 14. These bubblers 20 and 21 serve as means for supplying condensable gas. The number of bubblers used may be changed to one or three or more as needed. When using air from the atmosphere directly, the configuration may be as shown in Figure 3, with the atmospheric introduction pipe 43 connected between the solenoid valve 9 and the mass flow controller 18. In this configuration, the use of the illustrated mass flow controller may be omitted. Also, when measuring under atmospheric humidity conditions, air can be introduced directly into the membrane module without using bubblers. The atmospheric air may be supplied to the atmospheric introduction pipe using a blower or compressor, etc.

[0026] Each inlet pipe 24 is equipped with a solenoid valve 15, and its lower end opens into a liquid, i.e., water 23, which is housed in a sealed container 22 in each bubbler 20, 21 and becomes a condensable gas when vaporized. Each outlet pipe 25 is equipped with a solenoid valve 16, and its lower end opens into a space above the liquid level of water 23 in each sealed container 22.

[0027] The water supply pipe 26 is connected to the water source 27, and water can be supplied from the water supply pipe 26 to each sealed container 22 by opening the solenoid valve 17 provided at the end of each bubbler 20, 21 that is connected to the sealed container 22.

[0028] During normal operation of the device, solenoid valves 13 and 14 are closed, and solenoid valves 15 and 16 are opened, so that the two bubblers 20 and 21 are connected in series to the humid gas introduction pipe 11.

[0029] Between the confluence of the dry gas introduction pipe 10 and the bypass pipe 11 and the test gas supply pipe 4, a thermometer 28, a hygrometer 29, and a pressure gauge 30 are sequentially installed. In this embodiment, the first measurement unit consists of the thermometer 28, the hygrometer 29, and the pressure gauge 30. Note that the installation order and number of these thermometers, hygrometers, and pressure gauges are not limited to these, and one or more may be installed at any position in the piping system as long as the temperature, humidity, and pressure of the test gas can be measured with the desired accuracy. In addition, the temperature and humidity of the test gas may be detected by other installation methods, such as inserting a thermometer and hygrometer inside the membrane module 1.

[0030] A cold trap 31 for removing water vapor, a back pressure valve 32, and a solenoid valve 33 are sequentially provided in the non-permeable gas discharge pipe 5, and the downstream end thereof is connected to an exhaust port 41. A cold trap 37 similar to the above cold trap 31 is provided in the permeable gas discharge pipe 7, and a thermometer 34, a hygrometer 35, and a pressure gauge 36 are sequentially provided between the permeable gas discharge pipe 7 and the cold trap 37. In the embodiment, the second measurement unit is composed of a thermometer 34, a hygrometer 35, and a pressure gauge 36. Note that the installation order and the number of these thermometers, hygrometers, and pressure gauges can be appropriately changed according to the measurement object, the required measurement accuracy, etc., and are not limited to the above configuration. A mass flow meter 38, which is a measurement means for measuring the amount of gas passing through the separation membrane element 2 over time, a solenoid valve 39, and a vacuum pump 40 are sequentially provided in the cold trap 37, and the downstream end thereof is connected to the exhaust port 41 together with the non-permeable gas discharge pipe 5 and is open to the atmospheric pressure. Note that the permeable gas amount may be measured by installing a soap film flow meter downstream of the vacuum pump. Further, as shown in FIG. 4, a thermometer 34b, a hygrometer 35b, and a pressure gauge 36b may be provided as a third measurement unit between the non-permeable gas discharge pipe 5 and the cold trap 31 and used in combination with or instead of the first measurement unit.

[0031] According to this embodiment, the mass flow controllers 18 and 19 adjust the amount of dried nitrogen gas flowing through the dry gas introduction pipe 10 and the amount of nitrogen gas with moisture flowing through the wet gas introduction pipe 11, and supply them into the membrane module 1 from the test gas supply pipe 4. The temperature, humidity, and pressure of the supplied test gas are adjusted using the mass flow controllers 18 and 19 and the back pressure valve 32. After confirming that the indicated values of the thermometer 28, the hygrometer 29, and the pressure gauge 30 are stable within the predetermined conditions, by checking the indicated values of the thermometer 34, the hygrometer 35, the pressure gauge 36, and the mass flow meter 38, the temperature, humidity, pressure, and flow rate of the gas permeating into the separation membrane element 2 under the predetermined test gas conditions are measured, and the water vapor permeability and nitrogen permeability can be obtained using these measured values. When the amount of nitrogen gas permeating into the separation membrane element is very small and difficult to measure, as shown in FIG. 5, a configuration may be adopted in which a carrier gas introduction pipe is connected between the permeated gas discharge pipe 7 and the thermometer 34 and an inert gas (argon, nitrogen, etc.) is supplied. Further, as in the embodiment of the overall view of FIG. 6(a) and the partial enlarged view of FIG. 6(b), a configuration may be adopted in which the insertion pipe 47 is inserted from the permeated gas discharge pipe 7 and an inert gas is supplied into the membrane from the carrier gas introduction pipe 46. Note that the configurations of FIGS. 5 and 6 may be replaced with FIG. 1.

[0032] The water vapor permeability P is calculated using the following formula Ｈ２Ｏ and the nitrogen permeability P Ｎ２ is calculated.

[0033] …

[0034] …

[0035] The nitrogen permeation flow rate Q Ｎ２ is measured by the mass flow meter 38, and the water vapor permeation flow rate Q Ｈ２Ｏ is obtained by dividing the water vapor pressure p ｐ，Ｈ２Ｏ measured by the hygrometer 35 on the permeation side by the nitrogen partial pressure p ｐ，Ｎ２ on the permeation side and then multiplying by Q Ｎ２ (Q Ｈ２Ｏ = Q Ｎ２ (p ｐ，Ｈ２Ｏ／ / p ｐ，Ｎ２ )), and p ｐ，Ｎ２ is the total pressure p ｐ，ｔｏｔａｌ measured by the pressure gauge 36 on the permeation side.kara p ｐ，Ｈ２Ｏ It can be obtained by subtracting (p ｐ，Ｎ２ = p ｐ，ｔｏｔａｌ -p ｐ，Ｈ２Ｏ Δp represents the partial pressure difference between the membrane supply side and the permeate side for each component, and S represents the membrane area being measured. Partial pressure difference of water vapor Δp Ｈ２Ｏ This refers to the water vapor pressure (inlet water vapor pressure) measured by the hygrometer 29 installed at the module-side inlet and the membrane-permeable water vapor pressure p ｐ，Ｈ２Ｏ The difference between these two can be used. More precisely, the logarithmic mean water vapor pressure difference using the non-permeable water vapor pressure obtained from the supply and permeation mass balance may be used. Partial pressure difference of nitrogen Δp Ｎ２ This uses the difference in nitrogen partial pressure obtained by subtracting the water vapor pressure from the total pressure measured by pressure gauges 30 and 36.

[0036] The pore diameter at which leakage occurs is estimated from the Kelvin equation, which describes capillary condensation within the pore, and the pore diameter d is used as the standard for pinholes. ｐ This is determined by the following Kelvin formula.

[0037]

[0038] Here, ν− is the molar volume of liquefied water vapor, σ is the surface tension, θ is the contact angle, R is the gas constant, T is the absolute temperature, and p ｓ，Ｈ２Ｏ This indicates the saturated vapor pressure at the measurement temperature. Therefore, depending on the pinhole size you want to measure, the water vapor pressure p Ｈ２Ｏ Adjust the relative water vapor pressure (p Ｈ２Ｏ / p ｓ，Ｈ２Ｏ When the Kelvin diameter (d) is 0.1, 0.3, and 0.5, Ｋｅｌｖｉｎ These correspond to 0.9, 1.7, and 3.0 nm, respectively (calculated with σ = 72 mN / m and θ = 0).

[0039] The appropriate supply flow rate depends on the membrane permeability, membrane area, degree of depressurization, and humidity of the supplied nitrogen, but the water vapor transmission rate is 0.000005 mol / (m³). ２ (s・Pa), a nitrogen permeability of 0.00000001 mol / (m) is considered to be low leakage. ２ In sPa, the test gas (relative water vapor pressure: 0.3, Kelvin diameter: 1.7 nm) is applied to a membrane area of ​​100 cm². ２A supply of 100 to 10,000 mL / min per unit is sufficient, and 1,000 mL / min or more is preferable; supplying more gas allows for more accurate measurements.

[0040] In the inspection system 100 of this embodiment, the measured values ​​from the first measurement unit (thermometer 28, hygrometer 29, and pressure gauge 30), the second measurement unit (thermometer 34, hygrometer 35, and pressure gauge 36), and the mass flow meter 38 are transmitted to the measurement unit 50. The measurement unit 50 performs the necessary calculations described above from each measured value and operates the valves (opening / closing control) and adjusts the flow rate. The measurement unit 50 then calculates the leak of the membrane module to be inspected and evaluates the membrane module. Transmission between the measurement unit 50 and each unit may be wired or wireless, and the measurement unit 50 may use known computing means such as a personal computer, tablet terminal, or smartphone. The measurement unit 50 may also use external computing means (cloud service, etc.) (not shown) connected via an internet line.

[0041] From the series of explanations, conventional membrane module leak tests only detect leaks in the entire membrane and cannot evaluate leaks or condensable gas permeability of individual separation membrane elements. However, using the inspection system of the embodiment, it is possible to evaluate individual separation membrane elements. Furthermore, since it does not require the measurement of nitrogen permeability under various humidity conditions, as is the case with conventional nano-palm porometry, evaluation results can be obtained quickly. In other words, according to the membrane module of the embodiment disclosed in each figure, performance evaluation and leak testing of individual separation membrane elements can be performed simultaneously.

[0042] Figure 2 is a partially enlarged schematic diagram showing the relationship between the separation membrane element 2 in the membrane module 1, the connecting adapter 6 which serves as a joint, and the permeate gas discharge pipe 7. In the inspection system 100 of this embodiment, multiple separation membrane elements 2 are installed (housed) in the membrane module 1. Previously, it was necessary to remove each separation membrane element 2 installed in the membrane module 1 and inspect them individually. In contrast, in the inspection system of this embodiment, as shown in Figure 2(a), the inspection of the first separation membrane element adjusts the inspection gas to predetermined conditions, and the measurement of nitrogen permeability and condensable gas permeability is completed. After this, as shown in Figure 2(b), the connection adapter 6 (joint) is replaced with the second separation membrane element, allowing for a quick transition to the next measurement. This simple operation is repeated. This operation and measurement makes it possible to precisely inspect multiple separation membrane elements in a short amount of time. It is also possible to evaluate multiple separation membrane elements simultaneously as inspection targets. Furthermore, if the separation membrane element is a hydrophobic membrane, an alcohol such as ethanol can be used as the condensable gas, and an alcohol meter can be used instead of a hygrometer.

[0043] This invention differs significantly from conventional membrane module leak testing techniques in that it allows for simultaneous performance evaluation and leak testing of individual separation membrane elements within a membrane module. This method enables efficient and accurate evaluation of individual separation membrane elements while they remain installed in the membrane module. This allows for rapid and accurate diagnosis of the separation membrane element's condition while avoiding risks associated with membrane handling, leading to improved maintenance efficiency and cost reduction. Therefore, it is expected to be utilized in many industrial sectors that employ membrane technology.

[0044] 1 Membrane module 2 Separation membrane element 3 End cap 4 Inspection gas supply pipe 5 Impermeable gas discharge pipe 6 Connection adapter (fitting) 7 Permeable gas discharge pipe (fitting) 8 Nitrogen source 9 Regulator (pressure adjustment means) 10 Dry gas inlet pipe 11 Wet gas inlet pipe 12 Solenoid valve 13 Solenoid valve 14 Solenoid valve 15 Solenoid valve 16 Solenoid valve 17 Solenoid valve 18 Mass flow controller (dry gas flow rate adjustment means) 19 Mass flow controller (wet gas flow rate adjustment means) 20 Bubbler 21 Bubbler 22 Airtight container 23 Water 24 Inlet pipe 25 Outlet pipe 26 Water supply pipe 27 Water source 28 Thermometer (first measurement unit) 29 Hygrometer (first measurement unit) 30 Pressure gauge (first measurement unit) 31 Cold trap 32 Back pressure valve (pressure adjustment means) 33 Solenoid valve 34 Thermometer (second measurement unit) 35 Hygrometer (second measurement unit) 36 Pressure gauge (second measurement unit) 34b Thermometer (third measurement unit) 35b Hygrometer (third measurement unit) 36b Pressure gauge (third measurement unit) 37 Cold trap 38 Mass flow meter 39 Solenoid valve 40 Vacuum pump 41 Exhaust port 42 Air source 43 Air inlet pipe 44 Argon source 45 Mass flow controller (argon flow rate adjustment means) 46 Carrier gas inlet pipe 47 Insertion pipe 50 Measurement unit 100 Inspection system

Claims

1. An inspection system characterized by comprising: a separation membrane element installed in a membrane module; a supply source for supplying a mixed gas to the membrane module with an adjusted mixing ratio of non-condensable gas and condensable gas; a first measuring unit provided in the middle of the piping between the supply source and the supply port of the membrane module; a fitting attached to the permeate-side outlet of the separation membrane element filled in the membrane module; an exhaust port for disposing of unwanted gas; a mass flow meter provided in the middle of the piping between the fitting and the exhaust port for measuring the flow rate of non-condensable gas; a second measuring unit provided in the piping between the fitting and the exhaust port; and a measurement unit that performs measurements of the first measuring unit and the second measuring unit, and measurements of the mass flow meter.

2. The inspection system according to claim 1, wherein a plurality of separation membrane elements are installed in the membrane module, and the fittings are attached to the permeate side outlets of each of the separation membrane elements when performing measurements in the first measurement unit and the second measurement unit, and when performing measurements in the mass flow meter.

3. The inspection system according to claim 1, characterized in that, when the separation membrane element is hydrophilic, nitrogen is used as the non-condensable gas and water as the condensable gas, and a hygrometer, thermometer, and pressure gauge are used as the first measurement unit and the second measurement unit, respectively.

4. The inspection system according to claim 1, characterized in that, when the separation membrane element is hydrophobic, nitrogen is used as the non-condensable gas and alcohol as the condensable gas, and an alcohol meter, a thermometer, and a pressure gauge are used as the first measurement unit and the second measurement unit.

5. A method for inspecting a membrane module using the inspection system described in claim 1, comprising: (a) supplying a mixed gas into a membrane module from a supply source of mixed gas having an adjusted mixing ratio of non-condensable gas and condensable gas, and adjusting the pressure of the condensable gas in the mixed gas according to the pinhole size to be detected while monitoring with a first measuring unit provided in the middle of the piping between the supply source and the supply port of the membrane module; (b) monitoring the supplied mixed gas using the first measuring unit as it passes through the separation membrane element to be inspected; (c) monitoring using a second measuring unit and a mass flow meter provided in the middle of the piping between a fitting attached to the permeable outlet of the separation membrane element and the exhaust port; and (d) simultaneously performing a performance evaluation and a leak test of the separation membrane element through the measuring unit based on the monitoring results from the first measuring unit, the second measuring unit and the mass flow meter.

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