Method of detecting defects in separation membrane elements and apparatus for detecting defects in separation membrane elements
阅读说明：本技术 检测分离膜元件中的缺陷的方法和用于检测分离膜元件中的缺陷的装置 (Method of detecting defects in separation membrane elements and apparatus for detecting defects in separation membrane elements ) 是由 洪慈敏 全亨濬 申程圭 李炳洙 于 2019-10-18 设计创作，主要内容包括：本说明书提供了用于检测分离膜元件的缺陷的方法和用于检测分离膜元件的缺陷的装置。(The present specification provides a method for detecting a defect of a separation membrane element and an apparatus for detecting a defect of a separation membrane element.)
1. A method for detecting a defect of a separation membrane element, the method comprising:
disposing the separation membrane element inside a pressure vessel; and
supplying a gas to a gas supply unit of the pressure vessel and measuring a permeability of the separation membrane element using the gas passing through the separation membrane element,
wherein the separation membrane included in the separation membrane element includes a porous layer and an active layer provided on the porous layer, and the active layer is a polyamide active layer; and
the separation membrane element is a spiral winding module.
2. The method for detecting a defect of a separation membrane element according to claim 1, wherein in the measurement of the permeability of the separation membrane element, the pressure vessel includes a gas discharge unit that discharges the gas that has passed through the separation membrane element outside the pressure vessel, and
the permeability of the separation membrane element is measured using the gas discharged to the gas discharge unit.
3. The method for detecting a defect of a separation membrane element according to claim 1, wherein the separation membrane element, the defect of which is detected by the method for detecting a defect of a separation membrane element, includes a center tube and a case, and
the gas supply to the gas supply unit of the pressure vessel is supplied between the central tube and the housing.
4. The method for detecting a defect of a separation membrane element according to claim 1, wherein a gas supply to a gas supply unit of the pressure vessel is a supply of a compressed gas of 0.1MPa or more and 0.7MPa or less.
5. The method for detecting a defect of a separation membrane element according to claim 1, comprising detecting a defect of the separation membrane element when a permeability of the separation membrane element measured with the gas passing through the separation membrane element is 0.095L/min (95ccm) or more.
6. The method for detecting defects of a separation membrane element according to claim 5, further comprising evaluating a salt rejection of the separation membrane element under conditions of 250g/L of sodium chloride (NaCl), 0.41MPa, 25 ℃, and 15% recovery.
7. The method for detecting a defect of a separation membrane element according to claim 6, wherein the evaluation of the salt rejection of the separation membrane element is to detect a defect of the separation membrane element when the salt rejection of the separation membrane element is 97% or less.
8. The method for detecting defects of a separation membrane element according to claim 5, further comprising evaluating the flux of the separation membrane element under conditions of 250g/L of sodium chloride (NaCl), 0.41MPa, 25 ℃, and 15% recovery.
9. The method for detecting a defect of a separation membrane element according to claim 8, wherein the evaluation of the flux of the separation membrane element is to detect a defect of the separation membrane element when the flux of the separation membrane element is 340L/day (90GPD) or more.
10. An apparatus for detecting defects of a separation membrane element, the apparatus comprising:
a pressure vessel including a gas supply unit and a gas discharge unit; and
a measurement unit that measures a permeability of the separation membrane element using the gas discharged to the gas discharge unit,
wherein the separation membrane included in the separation membrane element includes a porous layer and an active layer provided on the porous layer, and the active layer is a polyamide active layer; and
the separation membrane element is a spiral winding module.
11. The apparatus for detecting defects of a separation membrane element according to claim 10, wherein the gas discharge unit is provided to discharge the gas that has passed through the separation membrane element out of the pressure vessel when the gas is discharged from one end of the separation membrane element.
12. The apparatus for detecting a defect of a separation membrane element according to claim 10, wherein the separation membrane element, the defect of which is detected by the apparatus for detecting a defect of a separation membrane element, includes a center tube and a case, and
the gas supply unit is provided to supply the gas between the center pipe and the housing.
Technical Field
This application claims priority and benefit to korean patent application No. 10-2018-0124585, filed on 18.10.2018 from the korean intellectual property office, the entire contents of which are incorporated herein by reference.
The present specification relates to a method for detecting a defect of a separation membrane element and an apparatus for detecting a defect of a separation membrane element.
Background
In accordance with the manufacture of high-purity and high-functional materials and social demands such as protection of the global environment, separation membrane manufacturing techniques and process techniques have been widely applied to large-scale industrial processes from a simple laboratory scale.
Among them, as water shortage caused by global warming becomes more serious worldwide, water purification technology as technology for ensuring alternative water resources is receiving attention. Therefore, a water treatment method using a reverse osmosis membrane (core technology of next generation tap water business using alternative water resources such as seawater desalination or water reuse) is expected to lead the water industry market. Such reverse osmosis membrane permeated water using a reverse osmosis membrane is changed into pure water or water infinitely close to pure water, and is used in various fields such as medical sterile water or purified water for dialysis, or water for manufacturing semiconductors in the electronics industry.
In addition, separation membranes have been widely used in the field of gas separation including hydrogen and oxygen, and the like.
Disclosure of Invention
Technical problem
The present specification aims to provide a method for detecting a defect of a separation membrane element and an apparatus for detecting a defect of a separation membrane element.
Technical scheme
One embodiment of the present specification provides a method for detecting a defect of a separation membrane element, the method comprising: disposing a separation membrane element inside a pressure vessel; and supplying a gas to a gas supply unit of the pressure vessel and measuring a permeability of the separation membrane element using the gas passing through the separation membrane element, wherein the separation membrane included in the separation membrane element includes a porous layer; and an active layer provided on the porous layer, the active layer being a polyamide active layer, and the separation membrane element being a spiral wound module.
Another embodiment of the present specification provides an apparatus for detecting a defect of a separation membrane element, the apparatus including: a pressure vessel including a gas supply unit and a gas discharge unit; and a measuring unit that measures a permeability of the separation membrane element using the gas discharged to the gas discharge unit, wherein the separation membrane included in the separation membrane element includes a porous layer; and an active layer provided on the porous layer, the active layer being a polyamide active layer, and the separation membrane element being a spiral wound module.
Advantageous effects
The method for detecting defects of a separation membrane element and the apparatus for detecting defects of a separation membrane element according to the present specification using gas permeability have an advantage of being economical in terms of raw materials, energy, and the like, as compared to the detection of defects of a separation membrane element using brine.
Drawings
Fig. 1 shows an apparatus for detecting defects of a separation membrane element according to one embodiment of the present description.
Fig. 2 shows a separation membrane element according to one embodiment of the present description.
Fig. 3 shows a separation membrane according to one embodiment of the present description.
Fig. 4 shows a separation membrane according to one embodiment of the present description.
Fig. 5 shows the constitution of a separation membrane element according to an embodiment of the present specification.
Detailed Description
In the present specification, a description that a certain member is placed "on" another member includes not only a case where the certain member is in contact with the other member but also a case where another member exists between the two members.
In this specification, unless specifically stated to the contrary, the description that a certain component "includes" certain constituents means that other constituents can also be included, and other constituents are not excluded.
Hereinafter, the present specification will be described in more detail.
One embodiment of the present specification provides a method for detecting a defect of a separation membrane element, the method comprising: disposing a separation membrane element inside a pressure vessel; and supplying a gas to a gas supply unit of the pressure vessel and measuring a permeability of the separation membrane element using the gas passing through the separation membrane element, wherein the separation membrane included in the separation membrane element includes a porous layer; and an active layer provided on the porous layer, the active layer being a polyamide active layer, and the separation membrane element being a spiral wound module.
In a separation membrane element, flux and salt rejection are important performance indicators for the product of the separation membrane element. The performance indexes of flux and salt rejection can be determined by directly evaluating the separation membrane element using brine, however, when a defect occurs in the manufacturing process of the separation membrane element, low salt rejection and high flux are obtained. Determining the presence of a defect by directly evaluating a separation membrane element using brine as described above consumes many factors, such as time, raw materials (including brine), and energy. Further, since it is impossible to re-dry the separation membrane element after the evaluation with brine, there is a disadvantage in that weight increase due to wetting or the like is caused in the treatment.
Meanwhile, the method for detecting a defect of a separation membrane element and the apparatus for detecting a defect of a separation membrane element according to the present specification detect a defect of a separation membrane element using a gas permeability, and there are advantages in that: they are economical compared to the use of salt water for defect detection, and since there is no weight increase caused by wetting, the separation membrane elements are easy to handle after evaluating defect detection.
In the present specification, a "defect" of a separation membrane element may result from a crack which is not sealed due to the adhesive being partially uncoated or caused by physical damage during the process of assembling or processing the separation membrane element. Further, it may mean physical damage to the separation membrane caused by friction between the raw material and the auxiliary material during the winding process of the separation membrane element, however, the defect is not limited thereto.
In one embodiment of the present specification, disposing the separation membrane element inside the pressure vessel means introducing the separation membrane element into the pressure vessel and fixing the separation membrane element inside the pressure vessel.
By fixing the separation membrane element inside the pressure vessel, the permeability of the separation membrane element can be accurately measured.
The pressure vessel may be used without particular limitation in terms of material as long as the vessel is capable of sealing the supplied gas and is not corrosive. For example, stainless steel (SUS) may be used.
The pressure vessel may be cylindrical. When the pressure vessel is cylindrical, the pressure vessel size may be changed according to the size of the separation membrane element subjected to defect detection. For example, one section of the pressure vessel may have a diameter of 5cm to 21cm (2 inches to 8 inches) and a length of 30cm to 102cm (12 inches to 40 inches), however, the diameter and the length are not limited thereto.
In one embodiment of the present specification, supplying gas to the supply unit of the pressure vessel in supplying gas to the gas supply unit of the pressure vessel and measuring the permeability of the separation membrane element using the gas passing through the separation membrane element means introducing the gas to the separation membrane element in the same manner as introducing raw water. Specifically, the separation membrane element includes a center tube and a housing, and gas is supplied between the center tube and the housing.
The gas supplied between the center pipe and the housing may contact one side surface of the separation membrane. When the separation membrane includes a porous layer and an active layer disposed on the porous layer, one side surface of the separation membrane means an opposite surface of the active layer rather than a surface where the porous layer and the active layer are in contact with each other.
When the supplied gas permeates the separation membrane after contacting the one-side surface of the separation membrane, the supplied gas may permeate in a direction not parallel to the one-side surface of the separation membrane.
When the supplied gas permeates the separation membrane, the gas permeates the active layer and then permeates the porous layer in contact with the active layer. The gas permeating the porous layer is collected in the central tube by the warp knitted fabric.
Measuring the permeability of the separation membrane element after supplying the gas to the supply unit of the pressure vessel may measure the permeability of the separation membrane element after 30 seconds to 60 seconds after supplying the gas to the supply unit.
Measuring the permeability of the separation membrane element with the gas passing through the separation membrane element includes measuring the permeability using a flow meter.
In a method for detecting a defect of a separation membrane element provided in one embodiment of the present specification, in measuring a permeability of the separation membrane element, a pressure vessel includes a gas discharge unit that discharges a gas passing through the separation membrane element to the outside of the pressure vessel, and the permeability of the separation membrane element is measured using the gas discharged to the gas discharge unit.
In measuring the permeability of the separation membrane element using the gas discharged to the gas discharge unit, the gas discharged to the gas discharge unit means only the gas introduced to the gas discharge unit after the gas permeates the separation membrane included in the separation membrane element and is collected in the central pipe. In other words, the gas discharged to the gas discharge unit does not mean the gas that does not permeate the separation membrane included in the separation membrane elements.
In one embodiment of the present specification, a separation membrane element, the defects of which are detected by the method for detecting defects of a separation membrane element, includes a center tube and a housing, and a gas supply to a gas supply unit of a pressure vessel is supplied between the center tube and the housing.
For this case, the description provided below can be applied.
In one embodiment of the present description, the supply of gas to the supply unit of the pressure vessel is the supply of compressed gas greater than or equal to 0.1MPa (20psi) and less than or equal to 0.7MPa (100 psi). Preferably, the pressure of the compressed gas may be greater than or equal to 0.2MPa and less than or equal to 0.6MPa (greater than or equal to 30psi and less than or equal to 80psi), greater than or equal to 0.2MPa and less than or equal to 0.48MPa (greater than or equal to 30psi and less than or equal to 70psi), and more preferably greater than or equal to 0.25MPa and less than or equal to 0.45MPa (greater than or equal to 40psi and less than or equal to 60 psi). According to one example, the pressure of the compressed gas may be 0.35MPa (50 psi).
When the compressed gas supplied to the pressure vessel has a pressure satisfying the above range, the difference in permeability obtained by the presence or absence of defects is appropriate, and damage to the separation membrane element caused by pressurization is not generated, and thus the defects of the separation membrane element can be effectively classified.
A method for detecting a defect of a separation membrane element provided in one embodiment of the present specification includes detecting a defect of a separation membrane element when a permeability of the separation membrane element measured with a gas passing through the separation membrane element is 0.095L/min (95ccm) or more.
In the present specification, "gas" may mean dry air in an atmosphere including nitrogen, oxygen, carbon dioxide, and the like.
"ccm" means cc/min as a unit representing gas flux, and 1ccm may be 1 mL/min, and may be 0.001L/min.
The defect of the separation membrane element was detected when the permeability of the separation membrane element was 0.095L/min (95ccm) or more, and therefore, the upper limit thereof is not limited.
In one embodiment of the present specification, when the measured permeability of the separation membrane element is less than 0.095L/min (95ccm), no defect in the production process of the separation membrane element is detected, and excellent performance is obtained in the evaluation of the salt rejection and flux.
In the present specification, the permeability may be measured at 20 ℃ to 25 ℃, at room temperature, and preferably at 25 ℃.
In one embodiment of the present specification, the water content of the separation membrane element may be 1% to 3%.
The water content can be calculated by the following calculation formula.
[ calculation formula ]
In the calculation formula, heating means that the separation membrane is heated at a temperature of 100 ℃ for 1 minute and 30 seconds.
In one embodiment of the present specification, a separation membrane sample for measuring water content may have 30cm2To 50cm2And/or a weight of 0.3g to 0.7g, however, the area and weight are not limited thereto.
The method for detecting a defect of a separation membrane element provided in one embodiment of the present specification further includes evaluating a salt rejection of the separation membrane element under conditions of 250g/L (250ppm) of sodium chloride (NaCl), 0.41MPa (60psi), 25 ℃, and 15% recovery.
The evaluation of the salt rejection of the separation membrane element was to detect a defect of the separation membrane element when the salt rejection of the separation membrane element was 97% or less.
When the salt rejection of the separation membrane element is more than 97%, it can be determined that the separation membrane element has excellent salt rejection performance.
The method for detecting defects of a separation membrane element provided in one embodiment of the present specification further includes evaluating the flux of the separation membrane element under conditions of 250g/L (250ppm) of sodium chloride (NaCl), 0.41MPa (60psi), 25 ℃, and 15% recovery.
The evaluation of the flux of the separation membrane element was to detect a defect of the separation membrane element when the flux of the separation membrane element was 340L/day (90GPD) or more.
When the flux of the separation membrane element was less than 340L/day (90GPD), the flux of the separation membrane element was appropriately maintained, and it could be determined that the separation membrane element had excellent performance.
"GPD" means gallons per day as a unit representing flux, and 1GPD is about 3.8L per day.
The detection of the separation membrane element in one embodiment of the present specification may be determined such that when any one of the detection of a defect by evaluating the salt rejection of the separation membrane element and the detection of a defect by evaluating the flux of the separation membrane element is performed, the defect in the separation membrane element is detected when the target salt rejection and/or flux in the present specification is not satisfied.
Another embodiment of the present specification provides an apparatus for detecting a defect of a separation membrane element, the apparatus including: a pressure vessel including a gas supply unit and a gas discharge unit; and a measuring unit that measures a permeability of the separation membrane element using the gas discharged to the gas discharge unit, wherein the separation membrane included in the separation membrane element includes a porous layer; and an active layer provided on the porous layer, the active layer being a polyamide active layer, and the separation membrane element being a spiral wound module.
As for the description of the compressed gas supplied to the gas supply unit, the description provided above may be applied.
In one embodiment of the present specification, the gas discharge unit is configured to discharge gas outside the pressure vessel when the gas passing through the separation membrane element is discharged from one end of the separation membrane element.
In one embodiment of the present specification, a separation membrane element, the defect of which is detected by the apparatus for detecting a defect of a separation membrane element, includes a center tube and a housing, and a gas supply unit is provided to supply gas between the center tube and the housing.
In one embodiment of the present specification, the apparatus for detecting a defect of a separation membrane element may further include: a gas supply source; a supply line connected to a gas supply portion between a gas supply source and a pressure vessel; and an on-off valve installed on the supply line to supply or block the gas supplied from the gas supply source.
Further, the apparatus for detecting a defect of a separation membrane element may further include a pressure regulator installed on the supply line to regulate the pressure of the supplied gas; and a pressure gauge for observing the pressure of the supplied gas.
The apparatus for detecting a defect of a separation membrane element may further include a pressure gauge installed in the pressure vessel, as needed. A pressure gauge installed in the pressure vessel is used to compare the difference in pressure of the gas supplied through the supply unit.
In one embodiment of the present description, the apparatus for detecting a defect of a separation membrane element may further include a discharge line connected between the pressure vessel and the flow meter.
In one embodiment of the present specification, the measurement unit includes a flow meter that measures a permeability of the gas discharged to the gas discharge unit. In other words, the measurement unit may mean a flow meter.
The flow meter can generate a potential difference corresponding to the permeation rate by directly sensing the permeation rate.
As the flow meter, a bubble flow meter may be used. As the permeability of the separation membrane element, the permeability was measured by applying a pressure of 0.35MPa (50psi) to the separation membrane element under the conditions of room temperature (25 ℃) and 1atm (101,325Pa) for a period of 3 minutes to 5 minutes using a bubble flow meter for a total of 5 times, and the average value thereof could be measured by calculation.
The apparatus for detecting a defect of a separation membrane element may further include a fixing unit that fixes the separation membrane element inside the pressure vessel, as needed.
The fixing unit may be used without limitation in shape or size as long as it can fix the separation membrane element inside the pressure vessel without moving.
The fixing unit may further include a sealing unit that prevents leakage and discharge of gas discharged from a central tube included in the separation membrane element by being connected to the gas discharge unit.
By including the sealing unit, cracks or micro gaps in the apparatus for detecting defects of the separation membrane element can be prevented.
The sealing unit may include an O-ring, but is not limited thereto.
In one embodiment of the present specification, the separation membrane element is manufactured so as not to have a pressure decrease caused by a volume increase when gas is supplied to produce gas permeation.
In one embodiment of the present specification, the separation membrane included in the separation membrane element may be a water treatment membrane. The water treatment membrane can be used as a microfiltration membrane, an ultrafiltration membrane, a nanofiltration membrane, a reverse osmosis membrane, or the like, and can be preferably used as a reverse osmosis membrane.
In one embodiment of the present description, the separation membrane comprises a porous layer; and an active layer disposed on the porous layer.
The porous layer may include a first porous support and a second porous support.
As the first porous support, a nonwoven fabric may be used. As the material of the nonwoven fabric, polyethylene terephthalate may be used, however, the material is not limited thereto.
The thickness of the nonwoven fabric may be 50 μm to 150 μm, however, the thickness is not limited thereto. The thickness may preferably be 80 μm to 120 μm. When the nonwoven fabric thickness satisfies the above range, the durability of the separation membrane including the porous layer can be maintained.
The second porous support may mean that a coating layer made of a polymer material is formed on the first porous support. Examples of the polymer material may include polysulfone, polyethersulfone, polycarbonate, polyethylene oxide, polyimide, polyetherimide, polyetheretherketone, polypropylene, polymethylpentene, polymethylchloride, polyvinylidene fluoride, and the like, but are not limited thereto. Specifically, polysulfone may be used as the polymer material.
The thickness of the second porous support may be 20 μm to 100 μm, however, the thickness is not limited thereto. The thickness may preferably be 40 μm to 80 μm. When the coating layer thickness satisfies the above range, the durability of the separation membrane including the porous layer having the second porous support can be suitably maintained.
According to one embodiment, the second porous support layer may be prepared using a polymer solution comprising polysulfone. The polysulfone-containing polymer solution may be a homogeneous liquid obtained by: 10 to 20 wt% of polysulfone solid is introduced into 80 to 90 wt% of dimethylformamide solvent based on the total weight of the polysulfone-containing polymer solution, and the solid is dissolved at 80 to 85 ℃ for 12 hours, however, the weight range is not limited to the above range.
When the polysulfone solid is contained in the above-described range based on the total weight of the polysulfone-containing polymer solution, the durability of the separation membrane including the second porous support can be suitably maintained.
The second porous support may be formed using a casting method. Casting means a solution casting method, and specifically, may mean the following method: the polymer material is dissolved in a solvent, the solution is spread on a smooth surface without adhesion, and then the solvent is replaced. Specifically, the method of replacing the solvent may use a non-solvent induced phase separation method. The non-solvent induced phase separation method is a method of: wherein the polymer is dissolved in a solvent to form a homogeneous solution and, after shaping the solution into a certain form, it is immersed in a non-solvent. Thereafter, exchange occurs by diffusion of the non-solvent and the solvent, thereby changing the composition of the polymer solution, and as the polymer precipitates, the portions occupied by the solvent and the non-solvent form pores.
The active layer may be a polyamide active layer.
The polyamide active layer may be formed by: when the amine compound and the acid halide compound are brought into contact with each other, a polyamide is produced by interfacial polymerization while the amine compound reacts with the acid halide compound, and the polyamide is adsorbed on the porous layer. The contacting may be performed by methods such as dipping, spraying or coating. As the conditions for the interfacial polymerization, conditions known in the art may be used without limitation.
In order to form the polyamide active layer, an aqueous solution layer containing an amine compound may be formed on the porous layer. A method for forming an aqueous solution layer of an amine-containing compound on the porous layer is not particularly limited, and a method capable of forming an aqueous solution layer on the porous layer may be used without limitation. Specifically, the method for forming the aqueous solution layer of the amine-containing compound on the porous layer may include spraying, coating, dipping, dripping, and the like.
In this context, the aqueous solution layer of the amine-containing compound can be further subjected to removal of excess aqueous solution of the amine-containing compound, if desired. When the aqueous solution of the amine-containing compound present on the porous layer is too much, the aqueous solution layer of the amine-containing compound formed on the porous layer may be unevenly distributed, and when the aqueous solution of the amine-containing compound is unevenly distributed, an uneven polyamide active layer may be formed by subsequent interfacial polymerization. Therefore, after the aqueous solution layer containing the amine compound is formed on the porous layer, the excess aqueous solution is preferably removed. The method of removing the excess aqueous solution is not particularly limited, however, a method using a sponge, an air knife, a nitrogen purge, natural drying, a press roll, or the like may be used.
In the aqueous solution containing an amine compound, the amine compound is not limited in type as long as it is an amine compound used for the production of a separation membrane, however, specific examples thereof may preferably include m-phenylenediamine, p-phenylenediamine, 1,3, 6-benzenetriamine, 4-chloro-1, 3-phenylenediamine, 6-chloro-1, 3-phenylenediamine, 3-chloro-1, 4-phenylenediamine or a mixture thereof.
The solvent of the aqueous solution containing the amine compound may be water, and may include, in addition to this, acetone, dimethyl sulfoxide (DMSO), 1-methyl-2-pyrrolidone (NMP), or Hexamethylphosphoramide (HMPA).
The amine compound content may be greater than or equal to 1 wt% and less than or equal to 10 wt% relative to the total weight of the aqueous solution. When the above content is satisfied, the salt rejection and flux aimed in the present disclosure can be ensured.
The polyamide active layer may be prepared by: an aqueous solution of an amine-containing compound is coated on the porous layer, and then an organic solution containing an acid halide compound is brought into contact therewith, and the resultant is interfacially polymerized.
The acid halide compound is not limited as long as it can be used for polymerization of polyamide, however, specific examples thereof may preferably include one type selected from the group consisting of trimesoyl chloride, isophthaloyl chloride and terephthaloyl chloride, or a mixture of two or more types thereof, as the aromatic compound having 2 to 3 carboxylic acid halides.
The acid halide compound content may be greater than or equal to 0.01 wt% and less than or equal to 0.5 wt% relative to the total weight of the organic solution. When the above content is satisfied, the salt rejection and flux aimed in the present disclosure can be ensured.
As the organic solvent contained in the organic solution containing the acid halide compound, aliphatic hydrocarbon solvents having 5 to 12 carbon atoms (e.g., freon, hexane, cyclohexane and heptane), hydrophobic liquids not mixed with water such as alkanes (e.g., alkanes having 5 to 12 carbon atoms), and mixtures thereof (i.e., isopar (exxon), ISOL-c (sk chem), ISOL-g (exxon), etc.) may be used, however, the organic solvent is not limited thereto.
The organic solvent content may be 95 to 99.99% by weight with respect to the total weight of the organic solution containing the acid halide compound, however, the content is not limited thereto. When the above content is satisfied, the salt rejection and flux aimed in the present disclosure can be ensured.
The thickness of the polyamide active layer may be 10nm to 1000nm, however, the thickness is not limited thereto. The thickness may preferably be 300nm to 500 nm. When the polyamide active layer satisfies the above range, the salt rejection and flux intended in the present disclosure can be ensured.
In one embodiment of the present description, the separation membrane element may further include a warp knit fabric between the separation membranes. Warp knitted fabrics have a woven or knitted structure and have a porous surface structure to create space for the produced water to flow out.
In one embodiment of the present description, the separation membrane element may be a spiral wound module.
When the separation membrane element is a spiral wound module, defects that may occur during the winding process when manufacturing the separation membrane element can be detected, as compared to a flat panel module.
In one embodiment of the present description, a separation membrane element may include a housing.
The housing means a space in which the separation membrane element is stored, and is not particularly limited in terms of composition and manufacturing method, and general means known in the art may be employed without limitation.
The separation membrane element of the present specification is not particularly limited in other constitutions and manufacturing methods as long as it includes the above-described separation membrane, and general means known in the art may be employed without limitation.
In one embodiment of the present description, the separation membrane element may include a central tube.
The central tube may be denoted as a tube, and performs the function of a path through which the permeate gas is introduced and discharged.
The shape of the central tube is not particularly limited, but is preferably located at the center of the separation membrane element. Further, the center pipe may have one side surface opened so that the introduced gas is discharged.
In one embodiment of the present specification, the central tube may include a plurality of holes, and when gas permeates through the separation membrane element according to one embodiment of the present specification, permeate gas is introduced into the central tube through the plurality of holes of the central tube, and then the introduced gas is discharged through the open one side surface of the central tube.
The material of the center pipe is not particularly limited, and general materials known in the art may be used.
Hereinafter, the present disclosure will be described in more detail with reference to the accompanying drawings.
Fig. 1 shows a simulation of an apparatus for detecting defects of a separation membrane element according to the present description. The apparatus for detecting defects of a separation membrane element includes a pressure vessel 5, a gas supply unit 1 and a gas discharge unit 2, and a measurement unit 3 that measures the permeability of the separation membrane element by gas discharged to the gas discharge unit 2. The apparatus for detecting a defect of a separation membrane element may further include a gas supply source (feed), a supply line 11 connected to a gas supply portion between the gas supply source (feed) and the pressure vessel 5, and an on-off valve 12 installed on the supply line 11 to supply or block gas supplied from the gas supply source (feed).
Further, the apparatus for detecting a defect of a separation membrane element may further include a pressure regulator 13 installed on the supply line 11 to regulate the pressure of the supplied gas and a pressure gauge 4 observing the pressure of the supplied gas. The means for detecting defects of the separation membrane element may comprise a discharge line 22 connected between the pressure vessel 5 and the flow meter 3.
The measurement unit 3 includes a flow meter that measures the permeability of the gas discharged to the gas discharge unit 2. Further, as needed, the apparatus for detecting a defect of a separation membrane element may include a fixing unit that fixes the separation membrane element inside the pressure vessel. The fixing unit may further include a sealing unit 6, and the sealing unit 6 prevents leakage and discharge of gas discharged from a central tube included in the separation membrane element by being connected to the gas discharge unit. By including the sealing unit 6, cracks or micro gaps in the apparatus for detecting defects of the separation membrane element can be prevented.
When the on-off valve 12 is opened after gas is supplied from the gas supply source (feed) to the device for detecting defects of the separation membrane element, the gas is supplied along the supply line 11. The pressure regulator 13 may be used herein to regulate the pressure to a target pressure, and the regulated pressure may be determined by the pressure gauge 4. The supplied gas is introduced into the pressure vessel 5 and injected into the separation membrane element. The gas passing through the separation membrane element is collected in the central pipe and discharged to the discharge unit 2. After that, the discharged air is injected to a flow meter as the measurement unit 3 along the discharge line 22, and by the flow meter, the permeability of the separation membrane element can be measured. An apparatus for detecting a defect of a separation membrane element according to one embodiment of the present specification is not limited to the structure of fig. 1, and may also include another configuration.
Fig. 2 shows a separation membrane element according to the present description. The defects of the manufactured separation membrane element can be detected by manufacturing a spiral wound separation membrane element having a diameter of 1.8 inches and a length of 12 inches using a water treatment membrane (specifically, a reverse osmosis membrane). The separation membrane element includes a central tube 40 at the center. In the center pipe 40, the gas supplied by the supply unit of the above-described apparatus for detecting defects of separation membrane elements is collected after permeating the separation membrane elements, and the collected gas is discharged to the discharge unit of the apparatus for detecting defects of separation membrane elements through one side surface of the center pipe 40.
Fig. 3 illustrates a gas flow entering a separation membrane when a gas is supplied to a cross section of the separation membrane according to an embodiment of the present specification. When gas is supplied to the apparatus for detecting defects of a gas separation membrane element of the present specification, the supplied gas continuously permeates the active layer 300, the second porous support 200, and the first porous support 100 of the separation membrane and is collected along the warp-knitted fabric included in the separation membrane.
Fig. 4 illustrates that raw water, instead of gas, is introduced into a separation membrane according to an embodiment of the present specification. Specifically, fig. 4 shows a separation membrane in which a first porous support 100, a second porous support 200, and an active layer 300 are sequentially disposed. Brine 400 is introduced into the active layer 300, purified water 500 is discharged through the second porous support 100, and concentrated water 600 is discharged to the outside without passing through the active layer 300.
Fig. 5 illustrates introducing raw water to a separation membrane element according to an embodiment of the present specification. Specifically, a separation membrane element including a center tube 40, a feed spacer 20, a separation membrane 10, a warp knitted fabric filtration channel 30, and the like is formed. When raw water is caused to flow to the separation membrane elements, the raw water is introduced through the feed spacer 20 in the separation membrane elements. One or more separation membranes 10 extend in an outboard direction from the center tube 40 and are wrapped around the center tube 40. The feed spacer 20 forms a path through which raw water is introduced from the outside, and performs a role of maintaining a gap between one separation membrane 10 and another separation membrane 10. To this end, the feed spacer 20 is in contact with one or more separation membranes 10 on the upper and lower sides and is wound around a central tube 40. The warp knitted fabric filtration channel 30 generally has a fabric type structure, and performs a role of creating a flow path of a space through which water purified by the separation membrane 10 flows. The central tube 40 is located at the center of the separation membrane element, and performs the role of a path through which filtered water is introduced and discharged. Herein, it is preferable to form a hole having a certain size on the outer side of the center tube 40 to introduce filtered water, and it is preferable to form one or more holes.
EMBODIMENTS FOR CARRYING OUT THE INVENTION
Hereinafter, in order to specifically describe the present specification, the present specification will be described in detail with reference to examples. However, the embodiments according to the present specification may be modified into various different forms, and the scope of the present specification should not be construed as being limited to the embodiments described below. The embodiments of the present description are provided to more fully describe the present description to those of ordinary skill in the art.
Preparation example
Manufacture of apparatus for detecting defects of separation membrane element
As a porous support, a coating layer (polysulfone layer) was applied to a thickness of 60 μm on a nonwoven fabric (polyethylene terephthalate) having a thickness of 100 μm. The coating solution of the polysulfone layer was a homogeneous liquid obtained by: 15 wt% of polysulfone solid was introduced into 85 wt% of dimethylformamide solvent and the resultant was stirred at 80 to 85 ℃ for 12 hours. As the coating method, a die coating method is used.
Thereafter, a polyamide active layer was formed on the porous support by interfacial polymerization of m-phenylenediamine (m-PD) and trimesoyl chloride (TMC).
Specifically, an aqueous solution layer was formed on the porous support layer using an aqueous solution containing 5% by weight of m-phenylenediamine. Then, an organic solution containing 0.2% by weight of trimesoyl chloride (TMC) and 98% by weight of Isopar-G (organic solvent) was coated on the aqueous solution layer, and the resultant was subjected to interfacial polymerization to prepare a polyamide active layer having a thickness of 500 nm.
As a result, a separation membrane including a porous support and a polyamide active layer disposed on the porous support was manufactured.
Spiral wound separation membrane elements (including a center tube) were fabricated having dimensions of 1.8 inches in diameter and 12 inches in length, comprising a single sheet of separation membrane (leaf) 1.2m wide and 30cm high.
A pressure vessel having a diameter of 4 inches (101.6mm) and a length of 15 inches (381mm) capable of accommodating the separation membrane element manufactured above was prepared using a stainless steel material, and a device for detecting defects of the separation membrane element was manufactured by using a bubble flow meter (Gilibrator 2 of Sensidyne, LP) and a pressure gauge (digital pressure gauge of Sensys co.
Examples of the experiments.
Measurement of permeability of separation membrane element
Experimental example 1.
The produced separation membrane element was introduced into an apparatus for detecting a defect of the separation membrane element, and fixed.
After compressed air of 50psi (0.35MPa) was supplied to the supply unit, the permeability of the separation membrane element produced was measured in a flow meter (measuring unit). The results are described in table 1 below.
Specifically, the permeability was measured a total of 5 times under the conditions of room temperature (25 ℃) and 1atm (101,325Pa) for 3 to 5 minutes using a bubble flow meter, and the calculated average values were described in table 1 below.
Experimental example 2.
Permeability was measured in the same manner as in experimental example 1 except that the pressure of compressed air was changed to 30psi (0.2MPa), and the results were as described in examples 1-1 and 1-2 in table 2 below.
Evaluation of Performance of separation Membrane elements
After measuring the permeability of the separation membrane element, the performance of salt rejection and flux was evaluated under the conditions of sodium chloride (NaCl)250g/L (250ppm), 0.41MPa (60psi), and 15% recovery. The results are shown in tables 1 and 2 below.
[ Table 1]
Permeability (ccm)
Salt rejection (%)
Flux (GPD)
Defect detection
Example 1
73.58
97.61
82
Good quality
Example 2
74.01
97.63
81
Good quality
Example 3
74.86
97.02
83
Good quality
Example 4
83.01
97.23
82
Good quality
Example 5
83.10
97.5
84
Good quality
Example 6
94.49
97.33
83
Good quality
Comparative example 1
103.16
96.89
90
Failure of the product
Comparative example 2
118.46
95.02
105
Failure of the product
Comparative example 3
125.09
94.28
126
Failure of the product
Comparative example 4
130.52
94.02
133
Failure of the product
[ Table 2]
Permeability (ccm)
Salt rejection (%)
Flux (GPD)
Defect detection
Examples 1 to 1
41.94
97.61
82
Good quality
Examples 1 to 2
42.93
97.63
81
Good quality
In tables 1 and 2, permeability units ccm means cc/min and flux units GPD means gallons/day. Further, "good quality" in defect detection means that no defect is detected in the separation membrane element, and "poor" means that a defect is detected in the separation membrane element.
From the results of table 1 and table 2, it was determined that defects were detected in the separation membrane element when the permeability of the separation membrane element was 95ccm (0.095L/min) or more. Further, it was determined that in the evaluation of the performance of the separation membrane element, when the salt rejection was 97% or less and the flux was 90GPD (340L/day) or more, defects were detected in the separation membrane element and the performance was degraded.
In the foregoing, preferred embodiments of the present disclosure have been described, however, the present disclosure is not limited thereto, and various modifications may be made in the scope of the claims and the detailed description of the present disclosure, and these modifications also fall within the scope of the present disclosure.
[ reference numerals ]
1: gas supply unit
11: supply line
12: switch valve
13: pressure regulator
2: gas discharge unit
3: measuring unit (flowmeter)
4: pressure gauge
5: pressure vessel
6: sealing unit
10: separation membrane
20: supply path
30: permeation pathway
40: central tube
100: a first porous support
101: porous layer
200: a second porous support
300: active layer
400: raw water
500: produced water
600: concentrated water
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