Method and application of repairing film, and leak repairing precursor preparation system

Abstract

The invention belongs to the technical field of molecular sieve membrane repairing, and particularly relates to a membrane repairing method, application and a leak repairing precursor preparation system. The method comprises the following steps: mixing a first mixed gas containing NO2 and SO2 with a second mixed gas containing water vapor to form a mixture; preparing a leak repairing precursor by adopting the mixture; and performing repair treatment on a to-be-repaired membrane by adopting the leak repairing precursor to obtain the repaired molecular sieve membrane. The method at least solves the technical problems that a uniform, continuous and compact membrane layer is difficult to form during preparation of the molecular sieve membrane or a damaged membrane layer is difficult to repair and use, the service life of the molecular sieve membrane is generally low, the molecular sieve membrane cannot continuously work for a long time, and the economic benefit of a membrane separation technology is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of molecular sieve membrane repair, and in particular relates to a membrane repair method and application, and a leak-repair precursor preparation system. Background Art

[0002] As one of the modern mainstream gas separation technologies, membrane separation technology has broad application prospects in industrial product gas production, comprehensive utilization of waste gas and environmental protection. Compared with other separation technologies, it has unique advantages: energy saving, no phase change, no secondary pollution, simple operation, compact structure, low maintenance cost, easy to scale up and easy to automate. Zeolite molecular sieve membrane, as one of the important members of inorganic porous membrane, has the advantages of high temperature resistance, antimicrobial resistance, good structural stability and stable chemical properties. It also has the separation selectivity of molecules with different kinetic diameters at the molecular scale, strong design and adaptability due to the pore structure similar to most molecular sizes and the narrow pore size distribution and uniform pores in the structure. The ideal molecular sieve membrane should be formed by highly cross-linked molecular sieve crystals, without any defects on the membrane, and the molecular sieving and adsorption of the molecular sieve membrane should be achieved through regular and uniform molecular sieve pores.

[0003] However, in the production of molecular sieve membranes, it is often difficult for the synthesized molecular sieve membranes to form a uniform, continuous, and dense film layer, which greatly reduces their separation performance. Furthermore, in the process of separating gases by molecular sieve membranes, affected by factors such as the impact and corrosion of the separated gas, the life of the molecular sieve membrane is generally low, and it cannot work continuously for a long time, reducing the economic benefits of membrane separation technology. In general, there are at least three technical problems in the preparation process or in the process of participating in gas separation of molecular sieve membranes: 1) It is difficult to form a uniform, continuous, and dense film layer after the molecular sieve membrane is prepared. 2) The molecular sieve membrane is easily damaged during the membrane separation process. 3) The separation efficiency of the molecular sieve membrane for certain separation systems is not high. Therefore, reducing the defects of the intercrystalline channels of the molecular sieve membrane and promptly repairing the damaged molecular sieve membrane play a vital role in improving the separation performance and economic benefits of the molecular sieve membrane. Summary of the invention

[0004] To solve the above problems, the present invention proposes a method and application of membrane repair, and a leak-proof precursor preparation system. The method at least solves the technical problems that the above-mentioned molecular sieve membrane is often difficult to form a uniform, continuous and dense membrane layer, the life of the molecular sieve membrane is generally low, and it cannot work continuously for a long time, which reduces the economic benefits of membrane separation technology.

[0005] One of the purposes of the present invention is to provide a method for repairing a membrane, comprising the following steps:

[0006] mixing a first mixed gas comprising NO2 and SO2 with a second mixed gas comprising water vapor to form a mixture;

[0007] Using the mixture to prepare a leak-proof precursor;

[0008] The leak-repairing precursor is used to perform repairing treatment on the membrane to be repaired to obtain a repaired molecular sieve membrane.

[0009] The present invention provides a method for repairing a membrane, wherein a first mixed gas and a second mixed gas are first mixed to prepare a leak-repairing precursor, which is then used to repair the membrane to be repaired. The first mixed gas and the second mixed gas are mixed to generate a small amount of the leak-repairing precursor, and the small amount of the leak-repairing precursor can be used as a seed to prepare a large amount of the leak-repairing precursor. The molecular sieve membrane prepared by the method has improved separation performance for the separation system. The method has simple steps and low cost, and can effectively extend the working life of the molecular sieve membrane, thereby improving the economic benefits of membrane separation technology.

[0010] As a possible implementation of the film repair method of the present invention, the first mixed gas contains NO2, SO2 and N2; wherein the volume ratio of NO2:SO2:N2 is (1-10):(1-10):(1-100).

[0011] As a possible implementation of the film repairing method of the present invention, the flow rate of the first mixed gas is 2 mL / min to 20 mL / min.

[0012] As a possible implementation of the film repair method of the present invention, the step of using the mixture to prepare a leak-proof precursor includes: reacting the mixture at a pressure of 0.1MPa to 5MPa and a temperature below -5°C for more than 24 hours to obtain the leak-proof precursor.

[0013] As a possible implementation of the method for repairing a membrane of the present invention, the repair treatment step includes: immersing the membrane to be repaired in the leak-repairing precursor, immersing and reacting for 24 hours to 48 hours under a pressure of -0.10MPa to -0.01MPa, soaking the reaction product in water and then washing it with water to neutrality to obtain the repaired membrane.

[0014] As a possible implementation of the film repairing method of the present invention, the humidity of the gas in the second mixed gas is 1% to 100%.

[0015] As a possible implementation of the membrane repair method of the present invention, in the leak repair precursor, the molar ratio of NO2:SO2:H2O is 2:1:(3-5).

[0016] As a possible implementation of the method for repairing a film of the present invention, the method further includes a step of cleaning the film to be repaired, including:

[0017] Wash the surface of the membrane to be repaired with water 2 to 5 times, each time for 1 to 3 minutes;

[0018] The membrane to be repaired is immersed in water, ultrasonically dried, and then purged with dry N2 to obtain the cleaned membrane to be repaired.

[0019] Furthermore, the ultrasonic time is 30s to 60s.

[0020] Furthermore, the drying temperature is 100°C to 200°C.

[0021] Furthermore, the dry N2 purge time is more than 6 hours.

[0022] Furthermore, during the dry N2 purge, the membrane to be repaired is placed in a molecular sieve membrane fixing device, and the dry N2 is blown head-on onto the membrane surface of the membrane to be repaired.

[0023] As a possible implementation of the method for repairing a membrane of the present invention, the repaired membrane is dried at 60° C. to 80° C. and calcined at a constant temperature for 3 h to 36 h to obtain a dry repaired membrane.

[0024] The second object of the present invention is to provide a leak-proof precursor preparation system, the system prepares the leak-proof precursor of one of the objects of the present invention, the system comprises:

[0025] A first mixed gas source, a second mixed gas source, a low temperature tank, a leak-proof precursor collection pipe and an exhaust gas treatment device;

[0026] The leak-proof precursor collection tube is immersed in the low-temperature tank;

[0027] The first mixed gas source and the second mixed gas source are respectively connected to one end of the leak-proof precursor collecting pipe, and the other end of the leak-proof precursor collecting pipe away from the first mixed gas source is connected to the exhaust gas treatment device.

[0028] The leak-sealing precursor preparation system provided by the present invention is used for preparing the leak-sealing precursor provided by the present invention.

[0029] As a possible implementation of the leak-plugging precursor preparation system of the present invention, the leak-plugging precursor collection tube includes a tetrafluoroethylene tube or a silicone tube.

[0030] Furthermore, reducers are provided at both ends of the leak-proof precursor collecting tube.

[0031] The third object of the present invention is to provide an application of the molecular sieve membrane repaired by the method provided by the present invention in the field of flue gas and exhaust gas collection or oxygen collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 This is a schematic diagram of the process of the film repair method in an embodiment of the present invention;

[0034] Figure 2 It is a structural schematic diagram of a leak-proof precursor preparation system in an embodiment of the present invention;

[0035] Figure 3 Schematic diagram of the structure of the leak-proof precursor collection tube in an embodiment of the present invention.

[0036] Explanation of the reference numerals: 1-first mixed gas source, 2-second mixed gas source, 3-low temperature tank, 4-leakage repair precursor collection pipe, 5-exhaust gas treatment device, 6-reducing joint. DETAILED DESCRIPTION

[0037] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0038] In the present invention, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0039] In the present invention, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple, respectively.

[0040] It should be understood that in various embodiments of the present invention, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0041] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0042] The weight of the relevant components mentioned in the description of the embodiments of the present invention may not only refer to the specific content of each component, but also indicate the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the description of the embodiments of the present invention, it is within the scope disclosed in the description of the embodiments of the present invention. Specifically, the mass described in the description of the embodiments of the present invention may be a mass unit known in the chemical industry such as μg, mg, g, kg, etc.

[0043] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. For example, without departing from the scope of the embodiments of the present invention, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0044] One of the purposes of the embodiments of the present invention is to provide a method for repairing a film, such as Figure 1 As shown, the following steps are included:

[0045] S1. Mixing a first mixed gas containing NO2 and SO2 with a second mixed gas containing water vapor to form a mixture.

[0046] S2. Using the mixture to prepare a leak-proof precursor.

[0047] S3. Using a leak-repairing precursor to perform a repairing treatment on the membrane to be repaired, thereby obtaining a repaired molecular sieve membrane.

[0048] A method for repairing a membrane provided by an embodiment of the present invention comprises first mixing a first mixed gas and a second mixed gas to prepare a leak-repairing precursor, which is then used to repair the membrane to be repaired. The first mixed gas and the second mixed gas are mixed to generate a small amount of leak-repairing precursor, and the small amount of leak-repairing precursor can be used as a seed to prepare a large amount of leak-repairing precursor. The separation performance of the molecular sieve membrane prepared by the method for the separation system is improved. The method has simple steps and low cost, and can effectively extend the working life of the molecular sieve membrane, thereby improving the economic benefits of membrane separation technology.

[0049] The leak-proof precursor refers to the intermediate complex formed by the complexation of NO2, SO2 and H2O under low temperature and low pressure.

[0050] [Step S1]

[0051] As a possible implementation of the method for repairing a membrane in an embodiment of the present invention, the repair membrane includes a molecular sieve membrane, and the type of molecular sieve membrane is conventional in the art and is not particularly limited in the embodiment of the present invention. However, as an example, it can be a SSZ-13 molecular sieve membrane with an α-Al2O3 carrier.

[0052] As a possible implementation of the film repair method in the embodiment of the present invention, in the above step S1, the first mixed gas contains NO2, SO2 and N2; wherein the volume ratio of NO2:SO2:N2 is (1-10):(1-10):(1-100). Exemplarily, the volume ratio can be 5:5:50, 1:1:1, 10:10:100, 8:8:50, 3:3:20, 2:5:1, 5:6:10 and other specific situations. In this case, NO2 and SO2 are used as the film repairing gas, and N2 can dilute the NO2 and SO2 in the first mixed gas without participating in the reaction; within this volume ratio range, NO2 and SO2 can react to generate the required leak repair precursor.

[0053] As a possible implementation of the film repair method in the embodiment of the present invention, in the above step S1, the flow rate of the first mixed gas is 2 mL / min to 20 mL / min.

[0054] As a possible implementation of the membrane repair method in the embodiment of the present invention, in the above step S1, the sources of NO2 and SO2 in the first mixed gas are recovered from flue gas. In this case, the method makes full use of the pollutants of NO2 and SO2 in the flue gas.

[0055] As a possible implementation of the film repair method in the embodiment of the present invention, in the above step S1, the second mixed gas includes water vapor and also includes N2 or clean air.

[0056] Clean air refers to air that does not contain moisture (or the moisture is negligible), dust or other solid particles.

[0057] As a possible implementation method of the film repair method in an embodiment of the present invention, the relative humidity of the second mixed gas is 1% to 100%. In the demonstration example, it can be 1%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 100% and other specific situations.

[0058] Humidity refers to the ratio of the actual water vapor content in the second mixed gas to the maximum possible water content at that temperature.

[0059] As a possible implementation of the method for repairing a membrane in an embodiment of the present invention, in the above step S1, the flow rate of the second mixed gas is 1 ml / min to 30 ml / min. Within this gas flow rate range, it is easy to collect the leak repair precursor for subsequent preparation. Exemplarily, the flow rate of the second mixed gas can be 1 ml / min, 5 ml / min, 10 ml / min, 15 ml / min, 20 ml / min, 25 ml / min, 30 ml / min, etc., typical but non-limiting flow rates or a range between any two flow rates.

[0060] [Step S2]

[0061] As a possible implementation of the method for repairing a membrane in an embodiment of the present invention, in the above step S2, the step of using a mixture to prepare a leak-proof precursor includes: reacting the mixture for more than 24 hours under the conditions of a pressure of 0.1MPa to 5MPa and a temperature below -5°C to obtain a leak-proof precursor. Under the reaction conditions, since the leak-proof precursor generation reaction is an exothermic reaction, low temperature conditions (below -5°C) are conducive to promoting the reaction. The leak-proof precursor is easy to volatilize under low pressure conditions, thereby being adsorbed on the defect sites of the molecular sieve membrane, blocking the defective pores of the molecular sieve membrane, and improving the integrity of the molecular sieve membrane.

[0062] As a possible implementation of the method for repairing a film in an embodiment of the present invention, in the above step S2, in the leak repair precursor, the molar ratio of NO2:SO2:H2O is 2:1:(3-5). For example, the molar ratio of NO2:SO2:H2O can be 2:1:3, 2:1:4, 2:1:5, etc. Within this range, the leak repair precursor can well repair the film to be repaired.

[0063] As a possible implementation of the film repair method in the embodiment of the present invention, in the above step S2, the leak repair precursor is stored at a temperature of 3° C. to 8° C. In this storage temperature range, the decomposition of the leak repair precursor can be suppressed and the storage time can be extended.

[0064] As a possible implementation of the method for repairing a film in an embodiment of the present invention, in the above step S2, the method further includes a step of cleaning the film to be repaired, including:

[0065] Wash the surface of the membrane to be repaired 2 to 5 times, each time for 1 to 3 minutes;

[0066] The membrane to be repaired is immersed in water, ultrasonically dried, and then purged with dry N2 to obtain a clean membrane to be repaired.

[0067] In this case, water washing removes dust and other visible impurity particles on the surface of the membrane to be repaired. Ultrasound removes impurities in the membrane to be repaired. Drying removes crystal water in the membrane to be repaired. Dry N2 purges remove crystal water in the membrane to be repaired. After washing, the membrane to be repaired is clean and free of impurities, which is convenient for subsequent repair steps and avoids side reactions.

[0068] In some embodiments, the ultrasonic time is 30s to 60s. Within this ultrasonic time range, impurities in the film to be repaired are effectively removed without damaging the structure of the film to be repaired. Exemplarily, the ultrasonic time can be 30s, 35s, 40s, 45s, 50s, 55s, 60s, 30s to 35s, 35s to 40s, 40s to 45s, 45s to 50s, 50s to 55s, 55s to 60s, and other specific situations.

[0069] In some embodiments, the drying temperature is 100° C. to 200° C. Within this drying temperature range, the crystal water in the film to be repaired can be removed efficiently without wasting energy or damaging the structure of the film to be repaired.

[0070] In some embodiments, the dry N2 purge time is more than 6 hours. Within this time range, the crystal water in the repaired molecular sieve membrane is further effectively removed.

[0071] In some specific embodiments, when the dry N2 is purged, the membrane to be repaired is placed in a molecular sieve membrane fixture, and the dry N2 is purged head-on on the membrane surface to be repaired. In this case, impurities and crystal water on the membrane surface can be removed.

[0072] As a possible implementation of the method for repairing the film in the embodiment of the present invention, the repaired film is dried at 60° C. to 80° C. to obtain a dry repaired film. In this drying temperature range, the crystal water in the repaired film is removed to obtain a dry repaired film.

[0073] In some embodiments, the temperature of the high temperature reaction is 200° C. to 800° C. In this temperature range, the leak-repairing precursor can react and bond with the groups at the defective parts of the membrane well without destroying the structure of the molecular sieve membrane, thereby obtaining a repaired molecular sieve membrane.

[0074] [Step S3]

[0075] As a possible implementation of the method for repairing a membrane in an embodiment of the present invention, in the above step S3, the repair treatment step includes: immersing the membrane to be repaired in a leak-repairing precursor, immersing and reacting at a pressure of -0.05MPa for 24h to 48h, soaking the reaction product in water and then washing it with water until it is neutral, and reacting it at 200℃ to 800℃ for 3h to 36h to obtain a repaired membrane. Under this reaction condition, low-pressure immersion for 24h to 48h can allow the leak-repairing precursor to fully enter the defects in the membrane to be repaired, and finally achieve the effect of repairing the membrane to be repaired. The reaction product is soaked in water to wash away the leak-repairing precursor remaining on the surface of the molecular sieve membrane.

[0076] The second purpose of the embodiment of the present invention is to provide a leak-proof precursor preparation system, the system prepares the leak-proof precursor of one of the purposes of the present invention, such as Figure 2 As shown, the system includes:

[0077] A first mixed gas source 1, a second mixed gas source 2, a low temperature tank 3, a leak repair precursor collection pipe 4 and an exhaust gas treatment device 5;

[0078] The leak-proof precursor collecting tube 4 is immersed in the low-temperature tank 3;

[0079] The first mixed gas source 1 and the second mixed gas source 2 are respectively connected to one end of the leak-proof precursor collecting pipe 4 , and the other end of the leak-proof precursor collecting pipe 4 away from the first mixed gas source is connected to the exhaust gas treatment device 5 .

[0080] The leak-repairing precursor preparation system provided in the embodiment of the present invention is used to prepare the leak-repairing precursor in the embodiment of the present invention.

[0081] As a possible implementation of the leak-plugging precursor preparation system in the embodiment of the present invention, the leak-plugging precursor collection tube includes a tetrafluoroethylene tube or a silicone tube.

[0082] In some embodiments, the diameter of the leak-proof precursor collection tube is 3 mm to 6 mm, and the length is 3 cm to 5 cm. Within this diameter and length range, the leak-proof precursor collection tube is used to prepare the leak-proof precursor, so that the first mixed gas and the second mixed gas can be fully mixed, and the reaction efficiency is high. In addition, within this diameter range, the collection rate of the leak-proof precursor is improved.

[0083] In some embodiments, Figure 3 As shown, reducers 6 are provided at both ends of the leak-proof precursor collecting pipe 4. In this case, the reducers control the pressure in the leak-proof precursor collecting pipe. When the pressure is significantly reduced, it indicates that the mixture reacts to generate a large amount of leak-proof precursor.

[0084] A reducer is a pipe connector used to connect two pipes or pipe fittings with different diameters. It usually includes interfaces with different diameters at both ends to achieve the transition and connection of pipe diameters. The diameter of the collection pipe of the leak-proof precursor is different from that of the gas flow pipe, so a reducer is required for conversion. For example, 1 / 8 inch to 6mm.

[0085] The third purpose of the embodiment of the present invention is to provide the use of the molecular sieve membrane repaired by the method provided by the first purpose of the present invention in flue gas and exhaust gas collection and oxygen collection.

[0086] The following describes the invention in conjunction with specific embodiments.

[0087] Example 1

[0088] This embodiment provides a method for repairing a film, the method comprising the following steps:

[0089] (1) The contents and components of the first mixed gas and the second mixed gas are obtained respectively by using the molar ratio of NO2:SO2:H2O in the leak-proof precursor to be 2:1:3;

[0090] The first mixed gas includes NO2, SO2 and N2 in a volume ratio of 5:5:50, and the flow rate of the first mixed gas is 10 mL / min;

[0091] The second mixed gas includes water vapor and clean air, and the humidity is 50%; the flow rate of the second mixed gas is 20 mL / min.

[0092] (2) Cleaning the membrane to be repaired: First, wash the membrane surface with water for 5 times, each time for 1 min, and the flushing volume is 20 ml / min. Then, immerse the membrane to be repaired in water, ultrasonically dry it, and then pass dry N2 to purge it for 12 hours.

[0093] (3) The first mixed gas and the second mixed gas are mixed to form a mixture.

[0094] (4) reacting the mixture at a pressure of 3 MPa and a temperature of -10°C for 24 hours to obtain a leak-proof precursor; wherein the leak-proof precursor is a water-sulfur-nitrogen leak-proof precursor.

[0095] (5) The membrane to be repaired after cleaning in (2) is immersed in the leak repair precursor, and the reaction is carried out at a pressure of -0.05 MPa for 24 hours. The reaction product is soaked in water and then washed with water until it is neutral.

[0096] (6) The membrane to be repaired after washing in (5) is calcined at 500°C for 6 hours to obtain a repaired membrane.

[0097] Example 2

[0098] A method for repairing a membrane proposed in Example 2 has the same steps as those in Example 1, except that: in (1), the molar ratio of NO2:SO2:H2O in the leak repair precursor is 2:1:4 to obtain the contents and components of the first mixed gas and the second mixed gas respectively;

[0099] The first mixed gas includes NO2, SO2 and N2, the volume ratio of NO2, SO2 and N2 is 1:1:1, and the flow rate of the first mixed gas is 2 mL / min;

[0100] The second mixed gas includes water vapor and clean air, and the humidity is 100%; the flow rate of the second mixed gas is 2 mL / min.

[0101] Example 3

[0102] A method for repairing a membrane proposed in Example 3 has the same steps as those in Example 1, except that: in (1), the molar ratio of NO2:SO2:H2O in the leak repair precursor is 2:1:5 to obtain the contents and components of the first mixed gas and the second mixed gas respectively;

[0103] The first mixed gas includes NO2, SO2 and N2, the volume ratio of NO2, SO2 and N2 is 1:1:1, and the flow rate of the first mixed gas is 11 mL / min;

[0104] The second mixed gas includes water vapor and clean air, and the humidity is 100%; the flow rate of the second mixed gas is 23 mL / min.

[0105] Example 4

[0106] Embodiment 4 provides a method for repairing a membrane, and the method steps are basically the same as those of Embodiment 1, except that:

[0107] (1), the first mixed gas comprises NO2, SO2 and N2, the volume ratio of NO2, SO2 and N2 is 10:10:100, and the flow rate of the first mixed gas is 20 mL / min;

[0108] The second mixed gas includes water vapor and N2, and the humidity is 80%; the flow rate of the second mixed gas is 15 mL / min.

[0109] Example 5

[0110] Embodiment 5 provides a method for repairing a membrane, and the method steps are basically the same as those of Embodiment 1, except that:

[0111] (1), the first mixed gas comprises NO2, SO2 and N2, the volume ratio of NO2, SO2 and N2 is 8:8:50, and the flow rate of the first mixed gas is 2 mL / min;

[0112] The second mixed gas includes water vapor and N2, and the humidity is 30%; the flow rate of the second mixed gas is 2 mL / min.

[0113] Example 6

[0114] Embodiment 6 proposes a method for repairing a membrane, and the method steps are basically the same as those of Embodiment 1, except that:

[0115] (1), the first mixed gas comprises NO2, SO2 and N2, the volume ratio of NO2, SO2 and N2 is 3:3:20, and the flow rate of the first mixed gas is 20 mL / min;

[0116] The second mixed gas includes water vapor and clean air, and the humidity is 1%; the flow rate of the second mixed gas is 30 mL / min.

[0117] Example 7

[0118] Embodiment 7 provides a method for repairing a membrane, and the method steps are basically the same as those of Embodiment 1, except that:

[0119] (1), the first mixed gas comprises NO2, SO2 and N2, the volume ratio of NO2, SO2 and N2 is 2:5:1, and the flow rate of the first mixed gas is 11 mL / min;

[0120] The second mixed gas includes water vapor and clean air, and the humidity is 1%; the flow rate of the second mixed gas is 2 mL / min.

[0121] Example 8

[0122] Embodiment 8 provides a method for repairing a membrane, and the method steps are basically the same as those of Embodiment 1, except that:

[0123] (1), the first mixed gas comprises NO2, SO2 and N2, the volume ratio of NO2, SO2 and N2 is 5:6:10, and the flow rate of the first mixed gas is 20 mL / min;

[0124] The second mixed gas includes water vapor and N2, and the humidity is 150%; the flow rate of the second mixed gas is 10 mL / min.

[0125] Example 9

[0126] Embodiment 9 proposes a method for repairing a membrane, and the method steps are basically the same as those of Embodiment 1, except that:

[0127] In (1), the second mixed gas includes water vapor and N2, and the flow rate is 20 ml / min.

[0128] In (5), the membrane to be repaired after cleaning in (2) is immersed in the leak repair precursor and reacted at a pressure of -0.05 MPa for 48 hours.

[0129] (6), the calcination temperature is 450°C and the calcination time is 48 h.

[0130] Example 10

[0131] Embodiment 10 provides a method for repairing a membrane, and the method steps are basically the same as those of Embodiment 1, except that:

[0132] The second mixed gas includes water vapor and N2, and the flow rate is 30 ml / min.

[0133] In (5), the membrane to be repaired after cleaning in (2) is immersed in the leak repair precursor and reacted at a pressure of -0.05 MPa for 36 hours.

[0134] (6), the calcination temperature is 600°C and the calcination time is 3 h.

[0135] Comparative Example 1

[0136] This comparative example proposes a method for repairing a membrane, and the method steps are basically the same as those in Example 1, except that:

[0137] Directly introduce the first mixed gas or the second mixed gas into the membrane surface to be repaired for 24 hours.

[0138] In order to verify the progress of the present invention in preparing the repaired molecular sieve membrane by the complex, the tubular membranes before and after the repair of the embodiment and the comparative example were tested for CO2 / N2 separation performance, and the results are shown in Table 1. The test steps are as follows:

[0139] A CO2 / N2 mixed gas with a volume ratio of 1:1 is passed into the air inlet of the membrane at a gas flow rate of 80mL / min. The mixed gas is fully heat exchanged in the water bath to reach 25°C. A back pressure valve is used at the remaining end to control the opening of the gas when it passes through, and the pressure at the air inlet is controlled to be maintained at 100kPa. The gas flow rate is tested at the permeation end using a soap bubble flowmeter, and the CO2 concentration is tested with a CO2 concentration analyzer to obtain the volume ratio of CO2 / N2 at the permeation end and the permeability of CO2 in the membrane, and then the CO2 / N2 separation performance of the tubular membrane is obtained. The CO2 / N2 gas separation test experiment is carried out on the tubular membrane before and after the repair, so as to change the separation performance of the tubular membrane and the permeability of CO2 before and after the repair.

[0140] Table 1

[0141]

[0142]

[0143] As can be seen from Table 1 above, the method for repairing a membrane proposed in an embodiment of the present invention first mixes the first mixed gas and the second mixed gas to prepare a leak repair precursor, which is then used to impregnate and repair the membrane to be repaired. The repaired molecular sieve membrane has a significantly improved gas separation coefficient (35-50). That is, the separation performance of the separation system is improved. The method is simple in steps and low in cost, and can effectively extend the working life of the molecular sieve membrane, thereby improving the economic benefits of membrane separation technology.

[0144] From the gas separation coefficient (55%) of the repaired membrane in Comparative Example 1, it can be seen that if only the first mixed gas or the second mixed gas is directly introduced into the membrane surface to be repaired, the first mixed gas or the second mixed gas will not form a complex that effectively repairs the molecular sieve membrane, resulting in a lower gas separation coefficient (6.54) of the repaired molecular sieve.

[0145] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for repairing a membrane, characterized in that: The method comprises the following steps: mixing a first mixed gas comprising NO2 and SO2 with a second mixed gas comprising water vapor to form a mixture; Using the mixture to prepare a leak-proof precursor; The leak-repairing precursor is used to perform repairing treatment on the membrane to be repaired to obtain a repaired molecular sieve membrane.

2. The method for repairing a film according to claim 1, characterized in that: The first mixed gas comprises NO2, SO2 and N2; Wherein, the volume ratio of NO2:SO2:N2 is 1-10:1-10:1-100; And / or, the flow rate of the first mixed gas is 2 mL / min to 20 mL / min.

3. The method for repairing a film according to claim 1 or 2, characterized in that: The step of using the mixture to prepare a leak-proof precursor comprises: reacting the mixture under the conditions of a pressure of 0.1 MPa to 5 MPa and a temperature of below -5°C for more than 24 hours to obtain the leak-proof precursor; And / or, the repairing step includes: immersing the membrane to be repaired in the leak-proof precursor, immersing it for 24h to 48h under a pressure of -0.10 to -0.01MPa, soaking the reaction product in water and then washing it to neutrality, and then heat-insulating it to obtain the repaired membrane.

4. The method for repairing a film according to claim 3, characterized in that: The second mixed gas includes water vapor and also includes N2 or clean air; The humidity of the second mixed gas is 1% to 100%; And / or, the flow rate of the second mixed gas is 1 ml / min to 30 ml / min.

5. The method for repairing a film according to claim 4, characterized in that: In the leak-proof precursor, the molar ratio of NO2:SO2:H2O is 2:1:3-5.

6. The method for repairing a film according to claim 5, characterized in that: The method further comprises the step of cleaning the film to be repaired, comprising: Wash the membrane surface to be repaired with water 2 to 5 times, each time for 1 to 3 minutes; The membrane to be repaired is immersed in water, ultrasonically dried, and then purged with dry N2 to obtain the cleaned membrane to be repaired.

7. The method for repairing a film according to claim 6, characterized in that: The ultrasound time is 30s to 60s; And / or, the drying temperature is 100° C. to 200° C.; And / or, the dry N2 purge time is more than 6 hours; And / or, during the dry N2 purge, the membrane to be repaired is placed in a molecular sieve membrane fixing device, and the dry N2 is blown head-on onto the membrane surface of the membrane to be repaired.

8. The method for repairing a film according to claim 7, characterized in that: The repaired membrane is dried at 60° C. to 80° C. and calcined at a constant temperature for 3 h to 36 h to obtain a dry repaired membrane.

9. A leak-proof precursor preparation system, characterized in that: The system is used to prepare the leak-proof precursor according to any one of claims 1 to 8, and the system comprises: A first mixed gas source, a second mixed gas source, a low temperature tank, a leak-proof precursor collection pipe and an exhaust gas treatment device; The leak-proof precursor collection tube is immersed in the low-temperature tank; The first mixed gas source and the second mixed gas source are respectively connected to one end of the leak-proof precursor collecting pipe, and the other end of the leak-proof precursor collecting pipe away from the first mixed gas source is connected to the exhaust gas treatment device.

10. Use of the molecular sieve membrane repaired by the method according to any one of claims 1 to 8 in the field of flue gas and exhaust gas collection or oxygen collection.

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