WO2012090811A1 - Concentration difference power generating method - Google Patents

Concentration difference power generating method Download PDF

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WO2012090811A1
WO2012090811A1 PCT/JP2011/079608 JP2011079608W WO2012090811A1 WO 2012090811 A1 WO2012090811 A1 WO 2012090811A1 JP 2011079608 W JP2011079608 W JP 2011079608W WO 2012090811 A1 WO2012090811 A1 WO 2012090811A1
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concentration
salt water
semipermeable membrane
concentration salt
membrane
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PCT/JP2011/079608
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French (fr)
Japanese (ja)
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富岡洋樹
栗原優
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東レ株式会社
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/002—Forward osmosis or direct osmosis
    • B01D61/0022—Apparatus therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03G—SPRING, WEIGHT, INERTIA OR LIKE MOTORS; MECHANICAL-POWER PRODUCING DEVICES OR MECHANISMS, NOT OTHERWISE PROVIDED FOR OR USING ENERGY SOURCES NOT OTHERWISE PROVIDED FOR
    • F03G7/00—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/002—Forward osmosis or direct osmosis

Definitions

  • the present invention relates to a power generation method using a osmotic pressure difference generated between two liquids having different concentrations, such as seawater and river water, using a semipermeable membrane useful for selective separation of a liquid mixture.
  • the conventional composite semipermeable membrane is usually composed of three layers: a separation functional layer for preventing salt content, a support membrane having a thickness of several tens of ⁇ m or more for supporting the structure of the separation functional layer, and a substrate for supporting them.
  • the current separation function layer does not block the salt content by 100%, the slightly permeated salt content from the salt water side to the fresh water side stays in the support membrane to cause concentration polarization, resulting in a decrease in osmotic pressure.
  • the amount of water permeation as a driving force for power generation is greatly reduced.
  • a concentration difference power generation method (Patent Document 1) characterized by reducing retention of salt is disclosed.
  • Patent Document 2 a method of forming an asymmetric membrane having a structure that supports a separation functional layer on a substrate with a large porosity
  • This invention makes it a subject to provide the density
  • the concentration difference power generation method of the present invention has a thickness of 0.1 ⁇ m or more and 10 ⁇ m or less, and an average pore radius measured by a positron annihilation lifetime measurement method of 0.25 nm or more and 5 nm or less.
  • a semi-permeable membrane separates the low-concentration salt water from the high-concentration salt water, thereby causing water flow from the low-concentration salt water to the high-concentration salt water, and driving the generator using the flow.
  • a semi-permeable membrane having no salt content in the membrane is obtained, and by using this membrane, a high water permeability is stably supplied, so that a high power generation amount can be continuously generated in the concentration difference power generation. Can be obtained.
  • the concentration difference power generation method of the present invention suppresses the retention of salt in the semipermeable membrane by using a specific semipermeable membrane, thereby suppressing a decrease in water permeability due to concentration polarization, and as a result, high The amount of power generation can be realized.
  • the semipermeable membrane used in the concentration difference power generation method of the present invention has a separation function capable of inhibiting salinity.
  • the thickness of the semipermeable membrane is preferably 0.1 ⁇ m or more and 10 ⁇ m or less. Furthermore, the thickness of the semipermeable membrane is preferably 1 ⁇ m or more, and preferably 8 ⁇ m or less.
  • the thickness of the semipermeable membrane can be controlled by the concentration of the film forming stock solution, the discharge amount of the film forming stock solution, the running speed of the support when discharging the film forming stock solution, and the like. By having the thickness within the above range, it is possible to withstand the pressure during operation of concentration difference power generation and to obtain sufficient water permeability.
  • the thickness of the semipermeable membrane is a value measured using a spectroscopic ellipsometer.
  • Examples of the material constituting the semipermeable membrane include polyamide formed by polycondensation of a polyfunctional amine and a polyfunctional acid halide, or cellulose acetate.
  • polyamide is preferable as the material of the semipermeable membrane from the viewpoint of the ability to prevent salt and high water permeability and the ease of forming a thin film having self-supporting properties.
  • the polyfunctional amine is at least one compound selected from an aliphatic polyfunctional amine and an aromatic polyfunctional amine.
  • the aliphatic polyfunctional amine is an aliphatic amine having two or more amino groups in one molecule, preferably a piperazine-based amine or a derivative thereof.
  • piperazine-based amines and derivatives thereof include piperazine, 2,5-dimethylpiperazine, 2-methylpiperazine, 2,6-dimethylpiperazine, 2,3,5-trimethylpiperazine, 2,5-diethylpiperazine, 2, 3,5-triethylpiperazine, 2-n-propylpiperazine, 2,5-di-n-butylpiperazine and the like can be mentioned.
  • piperazine and 2,5-dimethylpiperazine are preferable from the viewpoint of stability of performance expression.
  • the aromatic polyfunctional amine is an aromatic amine having two or more amino groups in one molecule.
  • the aromatic polyfunctional amine is not limited to a specific compound, but examples of the aromatic polyfunctional amine include metaphenylene diamine, paraphenylene diamine, and 1,3,5-triaminobenzene. .
  • N-alkylated products of these compounds are also included in the aromatic polyfunctional amine. Examples of the N-alkylated product include N, N-dimethylmetaphenylenediamine, N, N-diethylmetaphenylenediamine, N, N-dimethylparaphenylenediamine, and N, N-diethylparaphenylenediamine.
  • the polyfunctional acid halide is an acid halide having two or more carbonyl halide groups in one molecule, and is not particularly limited as long as it gives a polyamide by reaction with the amine.
  • Examples of the polyfunctional acid halide include oxalic acid, malonic acid, maleic acid, fumaric acid, glutaric acid, 1,3,5-cyclohexanetricarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid.
  • 1,3,5-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,3-benzenedicarboxylic acid, acid halides of 1,4-benzenedicarboxylic acid, and the like can be used.
  • the polyfunctional acid halides may be used alone or as a mixture.
  • the form of the semipermeable membrane may be any form such as a hollow fiber membrane or a flat membrane.
  • the semipermeable membrane should just have salt inhibition performance as mentioned above.
  • the semipermeable membrane may have a single layer structure formed of the above-described material. That is, it can be said that the semipermeable membrane is composed of only a so-called separation functional layer.
  • the semipermeable membrane has a pure water permeability coefficient of 1 ⁇ 10 ⁇ 12 m 3 / m 2 / s / Pa to 1 ⁇ 10 ⁇ 10 m 3 / m 2 / s / Pa, and a salt permeability coefficient of 1 ⁇ 10 ⁇ 9. If it is m / s or more and 3 ⁇ 10 ⁇ 5 m / s or less, a sufficient amount of water permeation for concentration difference power generation can be obtained.
  • the pure water permeability coefficient and salt permeability coefficient can be determined by the following methods. The following equation is known as a transport equation of the reverse osmosis method based on non-equilibrium thermodynamics.
  • Jv is the membrane permeation volume flux (m 3 / m 2 / s)
  • Lp is the pure water permeability coefficient (m 3 / m 2 / s / Pa)
  • ⁇ P is the pressure difference (Pa) on both sides of the membrane
  • ⁇ is the osmotic pressure difference (Pa) on both sides of the membrane
  • Js is the solute permeation flux (mol / m 2 / s)
  • P is the solute permeability (m / s)
  • Cm is the solute membrane.
  • the surface concentration (mol / m 3 ), Cp is the permeate concentration (mol / m 3 ), and C is the concentration on both sides of the membrane (mol / m 3 ).
  • the average concentration C on both sides of the membrane has no substantial meaning when the concentration difference between the two sides is very large as in a reverse osmosis membrane. Therefore, the following equation obtained by integrating equation (2) with respect to the film thickness is often used.
  • R ′ ⁇ (1-F) / (1- ⁇ F) (3)
  • F exp ⁇ -(1- ⁇ ) Jv / P ⁇
  • R ′ is the true rejection rate
  • R ′ 1 ⁇ Cp / Cm (5)
  • Lp can be calculated from the equation (1)
  • R ′ is measured by changing Jv in various ways
  • R ′ and 1 / Jv are plotted (3)
  • P and ⁇ can be obtained simultaneously by curve fitting the equation.
  • the average pore radius in the semipermeable membrane measured by the positron annihilation lifetime measurement method is preferably 0.25 nm or more and 5 nm or less.
  • the average pore radius is preferably 0.5 nm or less. When the average pore radius is within this range, sufficient water permeability and solute blocking performance can be obtained as a semipermeable membrane for concentration difference power generation.
  • the positron annihilation lifetime measurement method measures the time (in the order of several hundred picoseconds to several tens of nanoseconds) from when a positron is incident on a sample until it annihilates. This is a method for nondestructively evaluating information on the size, number density, and size distribution. Details of this measurement method are described in, for example, “Fourth Edition Experimental Chemistry Course” Vol. 14, p485, edited by The Chemical Society of Japan, Maruzen Co., Ltd. (1992).
  • positronium Ps which is a neutral hydrogen-like atom.
  • Ps is classified as para-positronium p-Ps or ortho-positronium o-Ps, depending on whether the positron and electron spins are antiparallel or parallel.
  • Para-positronium p-Ps and ortho-positronium o-Ps are generated at a ratio of 1: 3 by spin statistics. The average lifetime of each is 125 ps for p-Ps and 140 ps for o-Ps.
  • o-Ps overlaps with electrons other than the self-bonded substance, and the probability of causing annihilation called pick-off annihilation increases, and as a result, the average lifetime of o-Ps becomes as short as several ns.
  • the disappearance of o-Ps in the insulating material is due to the overlap of the o-Ps with the electrons present in the vacancy wall in the substance, so that the smaller the vacancy, the faster the annihilation rate. That is, the lifetime of o-Ps is related to the pore diameter in the insulating material.
  • the annihilation lifetime ⁇ due to the pick-off annihilation of o-Ps is obtained by using a positron annihilation lifetime curve measured by a positron annihilation lifetime measurement method, a nonlinear least square program POSITRONFIT (for example, P. Kirkegor et al., Computer Physics Communications, Volume 3, p240).
  • POSITRONFIT for example, P. Kirkegor et al., Computer Physics Communications, Volume 3, p240.
  • the details can be obtained from the analysis result of the fourth component, which is divided into four components by North Holland Publishing Company (1972).
  • the average pore radius R in the semipermeable membrane is a value obtained from the following equation (1) using the positron annihilation lifetime ⁇ described above.
  • Equation (1) shows the relationship when it is assumed that o-Ps exists in a hole with a radius R in an electron layer with a thickness ⁇ R, and ⁇ R is empirically determined to be 0.166 nm. (The details are described in Nakanishi et al., Journal of Polymer Science: Part B: Polymer Physics, Vol. 27, p1419, John Willie & Sons Incorporated (1989)).
  • a method for producing a semipermeable membrane will be described using a polyamide flat membrane as an example, but the present invention is not limited thereto.
  • Examples of the method for synthesizing polyamide include solution polymerization in an aprotic organic polar solvent such as N-methylpyrrolidone, dimethylacetamide, dimethylformamide, or interfacial polymerization using an aqueous medium.
  • Solution polymerization in an aprotic organic polar solvent has an advantage that the molecular weight of the polymer can be easily controlled.
  • the obtained polyamide is isolated and purified, redissolved in an aprotic organic polar solvent, and used as a film forming stock solution.
  • the polymer concentration in the film-forming stock solution is preferably 2 to 30% by mass. Within this concentration range, a uniform thin film can be formed.
  • the stock solution is discharged onto the support using a die or a die coater to form a polyamide thin film.
  • a film of polyolefin or polyerylene terephthalate or a glass plate can be used as the support.
  • the power generation method of the present invention includes: (a) separating low-concentration salt water and high-concentration salt water by any of the semipermeable membranes described above, thereby allowing water flow from low-concentration salt water to high-concentration salt water. And (b) driving the generator using the flow.
  • Such a power generation method is realized by a power generation system including a module including the above-described semipermeable membrane and a generator connected to the module.
  • a power generation system including a module including the above-described semipermeable membrane and a generator connected to the module.
  • An example of such a power generation system is shown in FIG. In FIG. 1, high-concentration salt water is indicated as “salt water”, and low-concentration salt water is indicated as “fresh water”.
  • the module 2 includes a semipermeable membrane 3, a high concentration salt water flow path 4 for supplying high concentration salt water to one surface (first surface) of the semipermeable membrane 3, and the other surface (second surface). And a low-concentration salt water flow path 5 for supplying low-concentration salt water.
  • a high-concentration salt water supply unit such as a pump and a low-concentration salt water supply unit may be connected to the high-concentration salt water channel 4 and the low-concentration salt water channel 5 on the upstream side in the direction of water flow.
  • the generator 6 is connected to the high-concentration salt water channel 4 downstream of the module 2.
  • a spiral semipermeable membrane element As the module, for example, a spiral semipermeable membrane element is used.
  • the spiral type semipermeable membrane element includes a cylindrical water collecting pipe having a large number of holes and a semipermeable membrane wound around the cylindrical water collecting tube.
  • the semipermeable membrane is wound together with a raw water channel material such as a plastic net, a permeated water channel material such as tricot, and a film for enhancing pressure resistance as necessary.
  • the semi-permeable membrane or a module using the same is brought into contact with one side (first surface) of the semi-permeable membrane while pressing high-concentration salt water, and the opposite surface (second surface).
  • a part of the low-concentration fresh water on the second surface side moves to the first surface side through the semipermeable membrane by the permeation phenomenon (step (a)).
  • the volume of the solution on the first surface side is increased by the amount of low-concentration fresh water that has permeated from the second surface side, so that the generator can be driven with a larger pressure than that input to the first surface side.
  • Step (b) energy used for power generation can be obtained.
  • the retention of salt in the membrane of the semipermeable membrane is suppressed, thereby suppressing a decrease in the water permeability due to concentration polarization.
  • a high power generation amount can be realized.
  • a semipermeable membrane obtained by the method described later was placed on a silicon wafer and measured using a spectroscopic ellipsometer.
  • the salt concentration of the permeated water was measured when a semipermeable membrane was permeated with a saline solution of 25 ° C., pH 6.5, and a salt concentration of 500 mg / L at an operating pressure of 0.5 MPa.
  • membrane permeation flux The membrane permeation flux (m 3 / m 2 / day) was determined from the daily water permeability (cubic meter) per square meter of membrane surface.
  • Comparative Example 2 3 mL of a 10% by weight N-methylpyrrolidone solution of polyamide obtained in Reference Example 1 was dropped on a glass plate, and a thin film was formed at a rotational speed shown in Table 1 using a spin coater, and then at 250 ° C. for 120 minutes. Dried. After drying, the thin film was peeled off from the glass plate in warm water.
  • the membrane permeation flux, desalting rate, pure water permeation coefficient, salt permeation coefficient, film thickness, and average pore radius were values shown in Table 1, respectively.
  • the membrane permeation flux and desalting are achieved.
  • the rate was balanced. That is, it was considered that a decrease in driving force was suppressed by using a semipermeable membrane having a thickness and an average pore radius within this range.
  • the present invention can be suitably used for concentration difference power generation in which a generator is driven using the flow from low-concentration salt water to high-concentration salt water generated when two liquids having different salinity concentrations are separated by a semipermeable membrane.

Abstract

A concentration difference power generating method wherein: a water flow from a low concentration salt water to a high concentration salt water is caused by separating the low concentration salt water and the high concentration salt water with a semipermeable membrane that has a thickness of 0.1-10 μm (inclusive) and an average pore radius as determined by positron annihilation lifetime measurement of 0.25-5 nm (inclusive); and a power generator is driven by utilizing the water flow.

Description

濃度差発電方法Concentration difference power generation method
　本発明は、液状混合物の選択的分離に有用な半透膜を用いた、例えば海水と河川水等の、濃度の異なる２液の間に生じる浸透圧差を利用した発電方法に関する。 The present invention relates to a power generation method using a osmotic pressure difference generated between two liquids having different concentrations, such as seawater and river water, using a semipermeable membrane useful for selective separation of a liquid mixture.
　近年、化石燃料の消費等による炭酸ガス増加が地球規模の環境問題となっており、新たな脱炭素エネルギー技術の探索が盛んに行われている。その一つとして、海水と淡水等の塩分濃度差エネルギーを利用する濃度差発電は、エネルギー源が無尽蔵でかつ環境負荷が極めて小さい点で大きな期待が寄せられている。塩分濃度差をエネルギーへ変換する方法として、とくに半透膜を利用した抗圧浸透法が注目されている。この方法は、塩分濃度の異なる２液を半透膜で隔てたときに、正浸透現象によって生じる淡水から塩水への流動を利用して水車発電機を駆動させるものであり、１９７６年にロブによって提唱された（Ｓ．ロブ、ジャーナル・オブ・メンブレン・サイエンス、１巻、ｐ４９およびｐ２４９、エルゼビア（１９７６））。 In recent years, an increase in carbon dioxide gas due to consumption of fossil fuels has become a global environmental problem, and search for new decarbonization energy technologies has been actively conducted. As one of them, concentration difference power generation using salt concentration difference energy such as seawater and fresh water is highly expected in that the energy source is inexhaustible and the environmental load is extremely small. As a method for converting the salinity difference into energy, the anti-pressure osmosis method using a semipermeable membrane has attracted attention. In this method, when two liquids with different salinity concentrations are separated by a semipermeable membrane, the turbine generator is driven using the flow from fresh water to salt water caused by the forward osmosis phenomenon. (S. Rob, Journal of Membrane Science, Volume 1, p49 and p249, Elsevier (1976)).
　抗圧浸透法については、これまでに、市販の複合半透膜等を用いた開発研究がなされてきたが、以下に述べる複合半透膜の構造上の問題から十分な発電量を得ることができなかった。すなわち、従来の複合半透膜は、塩分を阻止する分離機能層、分離機能層の構造を支える数十μｍ以上の厚さを持つ支持膜、さらにそれらを支持する基材、の３層から通常成り立っているが、現状の分離機能層では塩分を１００％阻止しないため、塩水側から淡水側へごくわずかながら透過した塩分が前記支持膜中に滞留して濃度分極を生じさせ、浸透圧の低下により発電の駆動力となる透水量が大きく減じる、という課題があった。 As for the anti-pressure osmosis method, development research using a commercially available composite semipermeable membrane has been carried out so far, but it is possible to obtain a sufficient amount of power generation due to the structural problems of the composite semipermeable membrane described below. could not. That is, the conventional composite semipermeable membrane is usually composed of three layers: a separation functional layer for preventing salt content, a support membrane having a thickness of several tens of μm or more for supporting the structure of the separation functional layer, and a substrate for supporting them. However, since the current separation function layer does not block the salt content by 100%, the slightly permeated salt content from the salt water side to the fresh water side stays in the support membrane to cause concentration polarization, resulting in a decrease in osmotic pressure. As a result, there has been a problem that the amount of water permeation as a driving force for power generation is greatly reduced.
　濃度分極の発生を防ぐ方法として、例えば、複合半透膜における支持膜の「（厚さ×孔の屈曲率）／空隙率」で規定される構造パラメーター値を小さくすることで支持膜中への塩分の滞留を減じることを特徴とする濃度差発電方法（特許文献１）が開示されている。 As a method for preventing the occurrence of concentration polarization, for example, by reducing the structural parameter value defined by “(thickness × hole bending rate) / porosity” of the support membrane in the composite semipermeable membrane, A concentration difference power generation method (Patent Document 1) characterized by reducing retention of salt is disclosed.
　また、濃度差発電に類似する用途である正浸透現象を利用した脱塩方法へ供する膜として、空隙率の大きな基材上へ分離機能層を支持する構造を有した非対称膜を形成させる方法（特許文献２）が開示されている。 In addition, as a membrane for use in a desalination method using the forward osmosis phenomenon, which is an application similar to concentration difference power generation, a method of forming an asymmetric membrane having a structure that supports a separation functional layer on a substrate with a large porosity ( Patent Document 2) is disclosed.
米国特許第７５６６４０２号US Pat. No. 7,756,402 米国特許第７４４５７１２号U.S. Pat. No. 7,445,712
　しかしながら上記従来の技術でも、発電の駆動力の低下という問題の解決には至っていなかった。本発明は、駆動力の低下を抑制することができる濃度差発電方法を提供することを課題とする。 However, even the above-described conventional technology has not yet solved the problem of a decrease in driving force of power generation. This invention makes it a subject to provide the density | concentration difference power generation method which can suppress the fall of a driving force.
　上記課題を達成するため、本発明の濃度差発電方法は、厚さが０．１μｍ以上１０μｍ以下であり、かつ陽電子消滅寿命測定法により測定された平均孔半径が０．２５ｎｍ以上５ｎｍ以下である半透膜で、低濃度塩水と高濃度塩水とを隔てることで、前記低濃度塩水から前記高濃度塩水への水の流動を生じさせること、および前記流動を利用して発電機を駆動させることを備える。 In order to achieve the above object, the concentration difference power generation method of the present invention has a thickness of 0.1 μm or more and 10 μm or less, and an average pore radius measured by a positron annihilation lifetime measurement method of 0.25 nm or more and 5 nm or less. A semi-permeable membrane separates the low-concentration salt water from the high-concentration salt water, thereby causing water flow from the low-concentration salt water to the high-concentration salt water, and driving the generator using the flow. Is provided.
　本発明により、膜中への塩分の滞留がない半透膜が得られ、この膜を用いることで、安定して高透水量が供給されることにより、濃度差発電において継続的に高発電量を得ることができる。 According to the present invention, a semi-permeable membrane having no salt content in the membrane is obtained, and by using this membrane, a high water permeability is stably supplied, so that a high power generation amount can be continuously generated in the concentration difference power generation. Can be obtained.
濃度差発電装置の概略を示した図である。It is the figure which showed the outline of the concentration difference power generation device.
　本発明の濃度差発電方法は、特定の半透膜を用いることで、半透膜の膜中における塩分の滞留を抑制し、それによって濃度分極による透水量の低下を抑制し、その結果、高い発電量を実現することができる。 The concentration difference power generation method of the present invention suppresses the retention of salt in the semipermeable membrane by using a specific semipermeable membrane, thereby suppressing a decrease in water permeability due to concentration polarization, and as a result, high The amount of power generation can be realized.
　１．半透膜
　本発明の濃度差発電方法で用いられる半透膜は、塩分を阻止することができる分離機能を有する。半透膜の厚さは０．１μｍ以上１０μｍ以下であることが望ましい。さらに、半透膜の厚さは、１μｍ以上であることが好ましく、８μｍ以下であることが好ましい。半透膜の厚さは、製造工程において、製膜原液の濃度、製膜原液の吐出量、製膜原液の吐出時の支持体の走行速度等で制御できる。厚さが上記範囲内にあることで、濃度差発電の運転中の圧力に耐え、かつ十分な透水性を得ることができる。 1. Semipermeable membrane The semipermeable membrane used in the concentration difference power generation method of the present invention has a separation function capable of inhibiting salinity. The thickness of the semipermeable membrane is preferably 0.1 μm or more and 10 μm or less. Furthermore, the thickness of the semipermeable membrane is preferably 1 μm or more, and preferably 8 μm or less. In the manufacturing process, the thickness of the semipermeable membrane can be controlled by the concentration of the film forming stock solution, the discharge amount of the film forming stock solution, the running speed of the support when discharging the film forming stock solution, and the like. By having the thickness within the above range, it is possible to withstand the pressure during operation of concentration difference power generation and to obtain sufficient water permeability.
　本書において、半透膜の厚さは、分光エリプソメーターを用いて測定される値である。 In this document, the thickness of the semipermeable membrane is a value measured using a spectroscopic ellipsometer.
　半透膜の構成材料としては、多官能アミンと多官能酸ハロゲン化物との重縮合により形成されたポリアミド、または酢酸セルロースなどが挙げられる。特に、塩分を阻止する性能および透水性が高いこと、さらに自己支持性を持つ薄膜形成のしやすさの観点から、半透膜の材料としてポリアミドが好ましい。 Examples of the material constituting the semipermeable membrane include polyamide formed by polycondensation of a polyfunctional amine and a polyfunctional acid halide, or cellulose acetate. In particular, polyamide is preferable as the material of the semipermeable membrane from the viewpoint of the ability to prevent salt and high water permeability and the ease of forming a thin film having self-supporting properties.
　ポリアミドについて説明する。ここで多官能アミンは、脂肪族多官能アミンと芳香族多官能アミンとから選ばれる少なくとも１つの化合物である。 The polyamide will be described. Here, the polyfunctional amine is at least one compound selected from an aliphatic polyfunctional amine and an aromatic polyfunctional amine.
　脂肪族多官能アミンとは、一分子中に２個以上のアミノ基を有する脂肪族アミンであり、好ましくはピペラジン系アミンおよびその誘導体である。ピペラジン系アミンおよびその誘導体としては、例えば、ピペラジン、２，５－ジメチルピペラジン、２－メチルピペラジン、２，６－ジメチルピペラジン、２，３，５－トリメチルピペラジン、２，５－ジエチルピペラジン、２，３，５－トリエチルピペラジン、２－ｎ－プロピルピペラジン、２，５－ジ－ｎ－ブチルピペラジンなどが挙げられる。性能発現の安定性から、特に、ピペラジン、２，５－ジメチルピペラジンが好ましい。 The aliphatic polyfunctional amine is an aliphatic amine having two or more amino groups in one molecule, preferably a piperazine-based amine or a derivative thereof. Examples of piperazine-based amines and derivatives thereof include piperazine, 2,5-dimethylpiperazine, 2-methylpiperazine, 2,6-dimethylpiperazine, 2,3,5-trimethylpiperazine, 2,5-diethylpiperazine, 2, 3,5-triethylpiperazine, 2-n-propylpiperazine, 2,5-di-n-butylpiperazine and the like can be mentioned. In particular, piperazine and 2,5-dimethylpiperazine are preferable from the viewpoint of stability of performance expression.
　また、芳香族多官能アミンとは、一分子中に２個以上のアミノ基を有する芳香族アミンである。芳香族多官能アミンは、具体的な化合物に限定されるものではないが、芳香族多官能アミンとして、例えば、メタフェニレンジアミン、パラフェニレンジアミン、１，３，５－トリアミノベンゼンなどが挙げられる。これらの化合物のＮ－アルキル化物も芳香族多官能アミンに含まれる。Ｎ－アルキル化物としてＮ，Ｎ－ジメチルメタフェニレンジアミン、Ｎ，Ｎ－ジエチルメタフェニレンジアミン、Ｎ，Ｎ－ジメチルパラフェニレンジアミン、Ｎ，Ｎ－ジエチルパラフェニレンジアミンなどが挙げられる。 The aromatic polyfunctional amine is an aromatic amine having two or more amino groups in one molecule. The aromatic polyfunctional amine is not limited to a specific compound, but examples of the aromatic polyfunctional amine include metaphenylene diamine, paraphenylene diamine, and 1,3,5-triaminobenzene. . N-alkylated products of these compounds are also included in the aromatic polyfunctional amine. Examples of the N-alkylated product include N, N-dimethylmetaphenylenediamine, N, N-diethylmetaphenylenediamine, N, N-dimethylparaphenylenediamine, and N, N-diethylparaphenylenediamine.
　多官能酸ハロゲン化物とは、一分子中に２個以上のハロゲン化カルボニル基を有する酸ハロゲン化物であり、上記アミンとの反応によりポリアミドを与えるものであれば特に限定されない。多官能酸ハロゲン化物としては、例えば、シュウ酸、マロン酸、マレイン酸、フマル酸、グルタル酸、１，３，５－シクロヘキサントリカルボン酸、１，３－シクロヘキサンジカルボン酸、１，４－シクロヘキサンジカルボン酸、１，３，５－ベンゼントリカルボン酸、１，２，４－ベンゼントリカルボン酸、１，３－ベンゼンジカルボン酸、１，４－ベンゼンジカルボン酸の酸ハロゲン化物、などを用いることができる。上記多官能酸ハロゲン化物は単独で使用されてもよいし、混合物として使用されてもよい。 The polyfunctional acid halide is an acid halide having two or more carbonyl halide groups in one molecule, and is not particularly limited as long as it gives a polyamide by reaction with the amine. Examples of the polyfunctional acid halide include oxalic acid, malonic acid, maleic acid, fumaric acid, glutaric acid, 1,3,5-cyclohexanetricarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid. 1,3,5-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,3-benzenedicarboxylic acid, acid halides of 1,4-benzenedicarboxylic acid, and the like can be used. The polyfunctional acid halides may be used alone or as a mixture.
　半透膜の形態は、中空糸膜、平膜、などどのような形態であってもよい。半透膜は、上述したように塩阻止性能を有していればよい。具体的な構成としては、半透膜は、上述の材料で形成された単層構造を有することができる。つまり、半透膜はいわゆる分離機能層のみで構成されているといえる。 The form of the semipermeable membrane may be any form such as a hollow fiber membrane or a flat membrane. The semipermeable membrane should just have salt inhibition performance as mentioned above. As a specific configuration, the semipermeable membrane may have a single layer structure formed of the above-described material. That is, it can be said that the semipermeable membrane is composed of only a so-called separation functional layer.
　半透膜は、純水透過係数が１×１０－１２ｍ３／ｍ２／ｓ／Ｐａ以上１×１０－１０ｍ３／ｍ２／ｓ／Ｐａ以下、塩透過係数が１×１０－９ｍ／ｓ以上３×１０－５ｍ／ｓ以下であると、濃度差発電へ供する透水量が十分得られる。なお純水透過係数および塩透過係数は以下の方法により求めることができる。非平衡熱力学に基づいた逆浸透法の輸送方程式として、以下の式が知られている。 The semipermeable membrane has a pure water permeability coefficient of 1 × 10 −12 m 3 / m 2 / s / Pa to 1 × 10 −10 m 3 / m 2 / s / Pa, and a salt permeability coefficient of 1 × 10 −9. If it is m / s or more and 3 × 10 −5 m / s or less, a sufficient amount of water permeation for concentration difference power generation can be obtained. The pure water permeability coefficient and salt permeability coefficient can be determined by the following methods. The following equation is known as a transport equation of the reverse osmosis method based on non-equilibrium thermodynamics.
　Ｊｖ＝Ｌｐ（ΔＰ－σ・Δπ）　　　　　　　　（１）
　Ｊｓ＝Ｐ（Ｃｍ－Ｃｐ）＋（１－σ）Ｃ・Ｊｖ　（２）
　ここで、Ｊｖは膜透過体積流束（ｍ３／ｍ２／ｓ）、Ｌｐは純水透過係数（ｍ３／ｍ２／ｓ／Ｐａ）、ΔＰは膜両側の圧力差（Ｐａ）、σは溶質反射係数、Δπは膜両側の浸透圧差（Ｐａ）、Ｊｓは溶質の膜透過流束（ｍｏｌ／ｍ２／ｓ）、Ｐは溶質の透過係数（ｍ／ｓ）、Ｃｍは溶質の膜面濃度（ｍｏｌ／ｍ３）、Ｃｐは透過液濃度（ｍｏｌ／ｍ３）、Ｃは膜両側の濃度（ｍｏｌ／ｍ３）、である。膜両側の平均濃度Ｃは、逆浸透膜のように両側の濃度差が非常に大きな場合には実質的な意味を持たない。そこで（２）式を膜厚について積分した次式がよく用いられる。 Jv = Lp (ΔP−σ · Δπ) (1)
Js = P (Cm−Cp) + (1−σ) C · Jv (2)
Here, Jv is the membrane permeation volume flux (m 3 / m 2 / s), Lp is the pure water permeability coefficient (m 3 / m 2 / s / Pa), ΔP is the pressure difference (Pa) on both sides of the membrane, σ Is the solute reflection coefficient, Δπ is the osmotic pressure difference (Pa) on both sides of the membrane, Js is the solute permeation flux (mol / m 2 / s), P is the solute permeability (m / s), and Cm is the solute membrane. The surface concentration (mol / m 3 ), Cp is the permeate concentration (mol / m 3 ), and C is the concentration on both sides of the membrane (mol / m 3 ). The average concentration C on both sides of the membrane has no substantial meaning when the concentration difference between the two sides is very large as in a reverse osmosis membrane. Therefore, the following equation obtained by integrating equation (2) with respect to the film thickness is often used.
　　Ｒ’＝σ（１－Ｆ）／（１－σＦ）　　　（３）
ただし、
　　Ｆ＝ｅｘｐ｛－（１－σ）Ｊｖ／Ｐ｝　（４）
であり、Ｒ’は真の阻止率で、
　　Ｒ’＝１－Ｃｐ／Ｃｍ　　　　　　　　　（５）
で定義される。ΔＰを種々変化させることにより（１）式からＬｐを算出でき、またＪｖを種々変化させてＲ’を測定し、Ｒ’と１／Ｊｖをプロットしたものに対して（３）、（４）式をカーブフィッティングすることにより、Ｐとσを同時に求めることができる。 R ′ = σ (1-F) / (1-σF) (3)
However,
F = exp {-(1-σ) Jv / P} (4)
R ′ is the true rejection rate,
R ′ = 1−Cp / Cm (5)
Defined by By changing ΔP in various ways, Lp can be calculated from the equation (1), R ′ is measured by changing Jv in various ways, and R ′ and 1 / Jv are plotted (3), (4) P and σ can be obtained simultaneously by curve fitting the equation.
　陽電子消滅寿命測定法により測定された半透膜中の平均孔半径は、０．２５ｎｍ以上５ｎｍ以下であることが好ましい。また、平均孔半径は、０．５ｎｍ以下であることが好ましい。平均孔半径がこの範囲にあることで、濃度差発電用半透膜として十分な透水量と溶質阻止性能が得られる。 The average pore radius in the semipermeable membrane measured by the positron annihilation lifetime measurement method is preferably 0.25 nm or more and 5 nm or less. The average pore radius is preferably 0.5 nm or less. When the average pore radius is within this range, sufficient water permeability and solute blocking performance can be obtained as a semipermeable membrane for concentration difference power generation.
　陽電子消滅寿命測定法とは、陽電子が試料に入射してから消滅するまでの時間（数百ピコ秒から数十ナノ秒オーダー）を測定し、その消滅寿命から約０．１～１０ｎｍの空孔の大きさ、数密度、さらには大きさの分布に関する情報を非破壊的に評価する手法である。この測定法については、例えば「第４版実験化学講座」第１４巻、ｐ４８５、日本化学会編，丸善株式会社（１９９２）に、その詳細が記載されている。 The positron annihilation lifetime measurement method measures the time (in the order of several hundred picoseconds to several tens of nanoseconds) from when a positron is incident on a sample until it annihilates. This is a method for nondestructively evaluating information on the size, number density, and size distribution. Details of this measurement method are described in, for example, “Fourth Edition Experimental Chemistry Course” Vol. 14, p485, edited by The Chemical Society of Japan, Maruzen Co., Ltd. (1992).
　陽電子と電子とは互いのクーロン力で結合することで、中性の水素様原子であるポジトロニウムＰｓを生成する。Ｐｓは、陽電子と電子のスピンが反平行か平行かによって、パラポジトロニウムｐ－Ｐｓまたはオルトポジトロニウムｏ－Ｐｓに分類される。パラポジトロニウムｐ－Ｐｓとオルトポジトロニウムｏ－Ｐｓとは、スピン統計によって１：３の割合で生成する。それぞれの平均寿命はｐ－Ｐｓで１２５ｐｓ、ｏ－Ｐｓで１４０ｐｓである。ただし、凝集状態の物質中では、ｏ－Ｐｓは、自己が結合しているのとは別の電子と重なって、ピックオフ消滅と呼ばれる消滅を起こす確率が高くなり、その結果ｏ－Ｐｓの平均寿命は数ｎｓまで短くなる。絶縁材料中のｏ－Ｐｓの消滅は、ｏ－Ｐｓが物質中の空孔壁に存在する電子と重なり合うことによるので、空孔が小さいほど-消滅速度が速くなる。すなわちｏ－Ｐｓの消滅寿命は、絶縁材料中の空孔径に関連づけられる。 The positron and the electron are bonded by mutual Coulomb force to generate positronium Ps which is a neutral hydrogen-like atom. Ps is classified as para-positronium p-Ps or ortho-positronium o-Ps, depending on whether the positron and electron spins are antiparallel or parallel. Para-positronium p-Ps and ortho-positronium o-Ps are generated at a ratio of 1: 3 by spin statistics. The average lifetime of each is 125 ps for p-Ps and 140 ps for o-Ps. However, in an aggregated material, o-Ps overlaps with electrons other than the self-bonded substance, and the probability of causing annihilation called pick-off annihilation increases, and as a result, the average lifetime of o-Ps Becomes as short as several ns. The disappearance of o-Ps in the insulating material is due to the overlap of the o-Ps with the electrons present in the vacancy wall in the substance, so that the smaller the vacancy, the faster the annihilation rate. That is, the lifetime of o-Ps is related to the pore diameter in the insulating material.
　ｏ－Ｐｓの上記ピックオフ消滅による消滅寿命τは、陽電子消滅寿命測定法により測定された陽電子消滅寿命曲線を、非線形最小二乗プログラムＰＯＳＩＴＲＯＮＦＩＴ（例えばＰ．キルケゴール他、コンピューター・フィジクス・コミュニケーションズ、３巻、ｐ２４０、ノース・ホランド・パブリッシング・カンパニー（１９７２）にその詳細が記載されている）により４成分に分割して解析した中の、第４成分の解析結果から得ることができる。 The annihilation lifetime τ due to the pick-off annihilation of o-Ps is obtained by using a positron annihilation lifetime curve measured by a positron annihilation lifetime measurement method, a nonlinear least square program POSITRONFIT (for example, P. Kirkegor et al., Computer Physics Communications, Volume 3, p240). The details can be obtained from the analysis result of the fourth component, which is divided into four components by North Holland Publishing Company (1972).
　本書において、半透膜中の平均孔半径Ｒは、上記の陽電子消滅寿命τを用いて、次式（１）から求められた値である。式（１）はｏ－Ｐｓが厚さΔＲの電子層にある半径Ｒの空孔に存在すると仮定した場合の関係を示したものであり、ΔＲは経験的に０．１６６ｎｍと求められている（中西他、ジャーナル・オブ・ポリマー・サイエンス：パートＢ：ポリマー・フィジクス、２７巻、ｐ１４１９、ジョン・ウィリー＆サンズ・インコーポレーテッド（１９８９）にその詳細が記載されている）。 In this document, the average pore radius R in the semipermeable membrane is a value obtained from the following equation (1) using the positron annihilation lifetime τ described above. Equation (1) shows the relationship when it is assumed that o-Ps exists in a hole with a radius R in an electron layer with a thickness ΔR, and ΔR is empirically determined to be 0.166 nm. (The details are described in Nakanishi et al., Journal of Polymer Science: Part B: Polymer Physics, Vol. 27, p1419, John Willie & Sons Incorporated (1989)).
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　２．半透膜の製造方法
　半透膜の製造方法について、ポリアミド平膜を例に挙げて説明するが、本発明はこれに限定されるものではない。 2. Method for Producing Semipermeable Membrane A method for producing a semipermeable membrane will be described using a polyamide flat membrane as an example, but the present invention is not limited thereto.
　ポリアミドを合成する方法としては、Ｎ－メチルピロリドン、ジメチルアセトアミド、ジメチルホルムアミド等の非プロトン性有機極性溶媒中での溶液重合、または水系媒体を使用する界面重合等が挙げられる。非プロトン性有機極性溶媒中での溶液重合には、ポリマーの分子量を制御しやすいという利点がある。 Examples of the method for synthesizing polyamide include solution polymerization in an aprotic organic polar solvent such as N-methylpyrrolidone, dimethylacetamide, dimethylformamide, or interfacial polymerization using an aqueous medium. Solution polymerization in an aprotic organic polar solvent has an advantage that the molecular weight of the polymer can be easily controlled.
　得られたポリアミドを単離して精製し、非プロトン性有機極性溶媒に再溶解し、製膜原液とする。製膜原液中のポリマー濃度は２～３０質量％が好ましい。この濃度範囲であれば均一な薄膜を形成することができる。 The obtained polyamide is isolated and purified, redissolved in an aprotic organic polar solvent, and used as a film forming stock solution. The polymer concentration in the film-forming stock solution is preferably 2 to 30% by mass. Within this concentration range, a uniform thin film can be formed.
　製膜原液を、口金やダイコーターを用いて、支持体上に吐出させ、ポリアミド薄膜を形成する。支持体としては、ポリオレフィンやポリエリレンテレフタレートのフィルムやガラス板を用いることができる。 The stock solution is discharged onto the support using a die or a die coater to form a polyamide thin film. As the support, a film of polyolefin or polyerylene terephthalate or a glass plate can be used.
　３．発電方法および発電システム
　本発明の発電方法は、（ａ）低濃度塩水と高濃度塩水とを上述したいずれかの半透膜によって隔てることで、低濃度塩水から高濃度塩水への水の流動を生じさせること、および（ｂ）その流動を利用して発電機を駆動させること、を備える。 3. Power generation method and power generation system The power generation method of the present invention includes: (a) separating low-concentration salt water and high-concentration salt water by any of the semipermeable membranes described above, thereby allowing water flow from low-concentration salt water to high-concentration salt water. And (b) driving the generator using the flow.
　このような発電方法は、上述の半透膜を備えるモジュールと、このモジュールに接続された発電機と、を備える発電システムによって実現される。このような発電システムの一例を図１に示す。図１では、高濃度塩水が「塩水」として、低濃度塩水が「淡水」として示される。 Such a power generation method is realized by a power generation system including a module including the above-described semipermeable membrane and a generator connected to the module. An example of such a power generation system is shown in FIG. In FIG. 1, high-concentration salt water is indicated as “salt water”, and low-concentration salt water is indicated as “fresh water”.
　図１において、モジュール２は、半透膜３と、半透膜３の片方の面（第１面）に高濃度塩水を供給する高濃度塩水流路４と、他方の面（第２面）に低濃度塩水を供給する低濃度塩水流路５とを備える。高濃度塩水流路４および低濃度塩水流路５にはそれぞれ、水の流れる方向において上流側に、ポンプ等の高濃度塩水供給部および低濃度塩水供給部が接続されてもよい。発電機６は、モジュール２の下流で、高濃度塩水流路４に接続される。 In FIG. 1, the module 2 includes a semipermeable membrane 3, a high concentration salt water flow path 4 for supplying high concentration salt water to one surface (first surface) of the semipermeable membrane 3, and the other surface (second surface). And a low-concentration salt water flow path 5 for supplying low-concentration salt water. A high-concentration salt water supply unit such as a pump and a low-concentration salt water supply unit may be connected to the high-concentration salt water channel 4 and the low-concentration salt water channel 5 on the upstream side in the direction of water flow. The generator 6 is connected to the high-concentration salt water channel 4 downstream of the module 2.
　モジュールとしては、例えばスパイラル型半透膜エレメントが用いられる。スパイラル型半透膜エレメントは、多数の孔を穿設した筒状の集水管と、その周囲に巻回された半透膜を備える。半透膜は、プラスチックネットなどの原水流路材と、トリコットなどの透過水流路材と、必要に応じて耐圧性を高めるためのフィルムと共に巻回される。 As the module, for example, a spiral semipermeable membrane element is used. The spiral type semipermeable membrane element includes a cylindrical water collecting pipe having a large number of holes and a semipermeable membrane wound around the cylindrical water collecting tube. The semipermeable membrane is wound together with a raw water channel material such as a plastic net, a permeated water channel material such as tricot, and a film for enhancing pressure resistance as necessary.
　上記の半透膜またはそれを用いたモジュールに対し、図１に示すように、半透膜の片面（第１面）に高濃度の塩水を加圧しながら接触させ、その反対面（第２面）に低濃度の淡水を接触させると、浸透現象によって、前記第２面側の低濃度の淡水の一部が半透膜を通って第１面側に移動する（工程（ａ））。その結果、第１面側の溶液が第２面側から透過した低濃度の淡水の分だけ大きな容積となるため、第１面側に入力したよりも大きな圧力で発電機を駆動することができる（工程（ｂ））。こうして、発電に用いるエネルギーを得ることができる。 As shown in FIG. 1, the semi-permeable membrane or a module using the same is brought into contact with one side (first surface) of the semi-permeable membrane while pressing high-concentration salt water, and the opposite surface (second surface). ) Is brought into contact with low-concentration fresh water, a part of the low-concentration fresh water on the second surface side moves to the first surface side through the semipermeable membrane by the permeation phenomenon (step (a)). As a result, the volume of the solution on the first surface side is increased by the amount of low-concentration fresh water that has permeated from the second surface side, so that the generator can be driven with a larger pressure than that input to the first surface side. (Step (b)). Thus, energy used for power generation can be obtained.
　上述した半透膜を用いることで、半透膜の膜中における塩分の滞留が抑制され、それによって濃度分極による透水量の低下を抑制される。その結果、本方法によると、高い発電量を実現することができる。
By using the semipermeable membrane described above, the retention of salt in the membrane of the semipermeable membrane is suppressed, thereby suppressing a decrease in the water permeability due to concentration polarization. As a result, according to this method, a high power generation amount can be realized.
　以下に実施例によって本発明をさらに詳細に説明するが、本発明はこれらの実施例によりなんら限定されるものではない。 Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
　実施例および比較例における測定は次のとおり行った。 The measurements in Examples and Comparative Examples were performed as follows.
　（膜厚の測定）
　シリコンウェハー上に、後述の手法で得られた半透膜を乗せ、分光エリプソメーターを用いて測定した。 (Measurement of film thickness)
A semipermeable membrane obtained by the method described later was placed on a silicon wafer and measured using a spectroscopic ellipsometer.
　（脱塩率）
　半透膜に、２５℃、ｐＨ６．５、塩濃度５００ｍｇ／Ｌの食塩水を０．５ＭＰａの操作圧力で透過させたときの透過水の塩濃度を測定した。得られた塩濃度を次の式に当てはめることで、脱塩率を求めた。
脱塩率＝１００×｛１－（透過水中の塩濃度／供給水中の塩濃度）｝。 (Desalination rate)
The salt concentration of the permeated water was measured when a semipermeable membrane was permeated with a saline solution of 25 ° C., pH 6.5, and a salt concentration of 500 mg / L at an operating pressure of 0.5 MPa. The salt concentration obtained was determined by applying the obtained salt concentration to the following equation.
Desalination rate = 100 × {1− (salt concentration in permeated water / salt concentration in feed water)}.
　（膜透過流束）
　膜面１平方メートル当たり、１日の透水量（立方メートル）から膜透過流束（ｍ３／ｍ２／日）を求めた。 (Membrane permeation flux)
The membrane permeation flux (m 3 / m 2 / day) was determined from the daily water permeability (cubic meter) per square meter of membrane surface.
　（参考例１）
　窒素雰囲気下、メタフェニレンジアミンのＮ－メチルピロリドン溶液に、等モルの１，３－ベンゼンジカルボン酸ジクロリドのＮ－メチルピロリドン溶液を、氷浴中で滴下した。滴下終了後、室温下３時間攪拌した後、メタノールにより再沈殿させて精製し、ポリアミド固形物を得た。
（実施例１～３、比較例１）
　参考例１で得たポリアミドのＮ－メチルピロリドン１０重量％溶液を、ガラス板上に３ｍＬ滴下し、スピンコーターを用いて表１に示す回転数で薄膜を形成させた後、１５０℃で１２０分間乾燥させた。乾燥後、温水中でガラス板から薄膜を剥離させた。 (Reference Example 1)
Under a nitrogen atmosphere, an equimolar N-methylpyrrolidone solution of 1,3-benzenedicarboxylic acid dichloride was dropped into an N-methylpyrrolidone solution of metaphenylenediamine in an ice bath. After completion of the dropwise addition, the mixture was stirred at room temperature for 3 hours and then purified by reprecipitation with methanol to obtain a polyamide solid.
(Examples 1 to 3, Comparative Example 1)
3 mL of a 10% by weight N-methylpyrrolidone solution of polyamide obtained in Reference Example 1 was dropped on a glass plate, and a thin film was formed at a rotation speed shown in Table 1 using a spin coater, and then at 150 ° C. for 120 minutes. Dried. After drying, the thin film was peeled off from the glass plate in warm water.
　（比較例２）
　参考例１で得たポリアミドのＮ－メチルピロリドン１０重量％溶液を、ガラス板上に３ｍＬ滴下し、スピンコーターを用いて表１に示す回転数で薄膜を形成させた後、２５０℃で１２０分間乾燥させた。乾燥後、温水中でガラス板から薄膜を剥離させた。 (Comparative Example 2)
3 mL of a 10% by weight N-methylpyrrolidone solution of polyamide obtained in Reference Example 1 was dropped on a glass plate, and a thin film was formed at a rotational speed shown in Table 1 using a spin coater, and then at 250 ° C. for 120 minutes. Dried. After drying, the thin film was peeled off from the glass plate in warm water.
　このようにして得られた薄膜を評価したところ、膜透過流束、脱塩率、純水透過係数、塩透過係数、膜厚、平均孔半径はそれぞれ表１に示す値となった。 When the thin film thus obtained was evaluated, the membrane permeation flux, desalting rate, pure water permeation coefficient, salt permeation coefficient, film thickness, and average pore radius were values shown in Table 1, respectively.
　このように、半透膜の厚みが０．１μｍ以上１０μｍ以下でかつ陽電子消滅寿命測定法により測定された平均孔半径が、０．２５ｎｍ以上５ｎｍ以下であることで、膜透過流束および脱塩率が両立された。すなわち、この範囲内の厚みと平均孔半径を有する半透膜を用いることで、駆動力の低下が抑制されると考えられた。 Thus, when the thickness of the semipermeable membrane is 0.1 μm or more and 10 μm or less and the average pore radius measured by the positron annihilation lifetime measurement method is 0.25 nm or more and 5 nm or less, the membrane permeation flux and desalting are achieved. The rate was balanced. That is, it was considered that a decrease in driving force was suppressed by using a semipermeable membrane having a thickness and an average pore radius within this range.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　本発明は、塩分濃度の異なる２液を半透膜で隔てたときに生じる低濃度塩水から高濃度塩水への流動を利用して発電機を駆動させる濃度差発電に好適に用いることができる。 The present invention can be suitably used for concentration difference power generation in which a generator is driven using the flow from low-concentration salt water to high-concentration salt water generated when two liquids having different salinity concentrations are separated by a semipermeable membrane.
　１　　発電システム
　２　　半透膜モジュール
　３　　半透膜
　４　　高濃度塩水流路
　５　　低濃度塩水流路
　６　　発電機 DESCRIPTION OF SYMBOLS 1 Power generation system 2 Semipermeable membrane module 3 Semipermeable membrane 4 High concentration salt water flow path 5 Low concentration salt water flow path 6 Generator

Claims (3)

  1. 　厚さが０．１μｍ以上１０μｍ以下であり、かつ陽電子消滅寿命測定法により測定された平均孔半径が０．２５ｎｍ以上５ｎｍ以下である半透膜で、低濃度塩水と高濃度塩水とを隔てることで、前記低濃度塩水から前記高濃度塩水への水の流動を生じさせること、および
    　前記流動を利用して発電機を駆動させること
    を備える濃度差発電方法。     A semi-permeable membrane having a thickness of 0.1 μm or more and 10 μm or less and an average pore radius measured by a positron annihilation lifetime measurement method of 0.25 nm or more and 5 nm or less, and separating low-concentration salt water and high-concentration salt water. And generating a flow of water from the low-concentration salt water to the high-concentration salt water, and driving a generator using the flow.
  2. 　厚さが０．１μｍ以上１０μｍ以下であり、かつ陽電子消滅寿命測定法により測定された平均孔半径が０．２５ｎｍ以上５ｎｍ以下である濃度差発電用半透膜。 A semi-permeable membrane for concentration difference power generation having a thickness of 0.1 μm to 10 μm and an average pore radius measured by a positron annihilation lifetime measurement method of 0.25 nm to 5 nm.
  3. 　第１面および第２面を有し、０．１μｍ以上１０μｍ以下の厚さを有し、かつ陽電子消滅寿命測定法により測定された０．２５ｎｍ以上５ｎｍ以下の平均孔半径を有する半透膜、前記半透膜の前記第１面に高濃度塩水を供給する高濃度塩水流路、および前記半透膜の前記第２面に低濃度塩水を供給する低濃度塩水流路を備える半透膜モジュールと、
    　前記高濃度塩水流路の下流で前記半透膜モジュールに接続される発電機と、
    を備える発電システム。     A semipermeable membrane having a first surface and a second surface, having a thickness of from 0.1 μm to 10 μm, and having an average pore radius of from 0.25 nm to 5 nm measured by a positron annihilation lifetime measurement method; A semi-permeable membrane module comprising a high-concentration salt water channel for supplying high-concentration salt water to the first surface of the semi-permeable membrane, and a low-concentration salt water channel for supplying low-concentration salt water to the second surface of the semi-permeable membrane When,
    A generator connected to the semipermeable membrane module downstream of the high concentration brine channel;
    A power generation system comprising:
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JP2016067989A (en) * 2014-09-29 2016-05-09 大阪瓦斯株式会社 Forward osmosis membrane separation method, water treatment equipment, and power generation facility
WO2022050008A1 (en) * 2020-09-03 2022-03-10 株式会社クラレ Composite semipermeable membrane

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JPH10337453A (en) * 1997-04-11 1998-12-22 Toray Ind Inc Semipermeable membrane and its production
JP2008517737A (en) * 2004-10-29 2008-05-29 東レ株式会社 Composite semipermeable membrane, method for producing the same, element using the same, fluid separation device, and water treatment method
JP2009047012A (en) * 2007-08-14 2009-03-05 Mitsubishi Electric Corp Osmotic pressure power generation system
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JPH10337453A (en) * 1997-04-11 1998-12-22 Toray Ind Inc Semipermeable membrane and its production
JP2008517737A (en) * 2004-10-29 2008-05-29 東レ株式会社 Composite semipermeable membrane, method for producing the same, element using the same, fluid separation device, and water treatment method
JP2009510301A (en) * 2005-09-20 2009-03-12 アクアポリン エーピーエス Biomimetic aqueous membrane with aquaporins used in the generation of salinity differential power
JP2009047012A (en) * 2007-08-14 2009-03-05 Mitsubishi Electric Corp Osmotic pressure power generation system

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016067989A (en) * 2014-09-29 2016-05-09 大阪瓦斯株式会社 Forward osmosis membrane separation method, water treatment equipment, and power generation facility
WO2022050008A1 (en) * 2020-09-03 2022-03-10 株式会社クラレ Composite semipermeable membrane

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