JPS6227008A - Membrane distillation device - Google Patents

Abstract

PURPOSE:To prevent wasteful heat release and to improve the thermal efficiency of the titled device by immersing a heater at the central part of a raw soln. passage. CONSTITUTION:A heat-transfer tube 2 is provided on the inside of a cylindrical outer pipe 1, a cooling heat-transfer medium passage 5 is formed in between and a rod-like heater 4 whose upper end is supported and whose lower end is made free is furnished at the central part of the heat-transfer tube 2. A membrane tube 3 firmly attached to and supported by a heater tube 13 is provided between the heater 4 and the heat-transfer tube 2, the inner side separated by the membrane 3 is used as the raw soln. passage 7 and the outer side is used as the evaporation space 6. The raw soln. introduced into the membrane tube 3 from a raw soln. inlet pipe 10 is heated by the heater 4 and only the vapor is permeated through the membrane tube 3, diffused to the evaporation space 6, cooled on the surface of the heat-transfer tube 2, condensed and introduced from a condensate outlet pipe 12 to the outside of the device. The solute in the raw soln. is blocked by the membrane 3 along with the liq. and concentrated in the membrane tube 3. The concd. raw soln. is discharged from a raw soln. exit 11.

Description

【発明の詳細な説明】 〈産業上の利用分野〉 本発明は、膜蒸留装置に関し、詳述すると、熱により原
液の蒸発を促進させて蒸留を行うサーモパーベーパレー
ションに関するものである。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a membrane distillation apparatus, and more specifically, to thermopervaporation, which performs distillation by promoting evaporation of a stock solution using heat.

〈従来技術〉 溶液を分離濃縮する方法として、液体蒸気は透過させる
が、液体自身は透過させない重合体多孔質膜の一次側に
高温の被処理液、即ち、例えば熱海水のような原液を流
通させ、原液から発生し、上記多孔質膜を透過した蒸気
を二次側で冷却して凝縮させ、このようにして−次側に
おいて原液を濃縮し、二次側において凝縮液を得るサー
モパーベーパレーションは既に知られており、また、そ
のための装置も従来より種々提案されている。<Prior art> As a method for separating and concentrating a solution, a high temperature liquid to be treated, that is, a raw liquid such as hot sea water, is passed through the primary side of a porous polymer membrane that allows liquid vapor to pass through but not the liquid itself. The vapor generated from the stock solution and passed through the porous membrane is cooled and condensed on the secondary side, thus concentrating the stock solution on the next side and obtaining a condensed liquid on the secondary side. ration is already known, and various devices for it have been proposed.

例えば特公昭４９−４５４６１号公報には、鉛直方向に
延びる多数の膜壁と多数の伝熱壁とが互いに並行的に空
間を隔てて設けられており、互いに隣接する２個の膜壁
の間には高温原液通路を、互いに隣接する２個の伝熱壁
の間には冷却水通路を、互いに隣接する膜壁と伝熱壁の
間には発生蒸気と蒸留水の通路となる蒸気空間をそれぞ
れ画定し、さらに装置本体の両端部には伝熱壁と側壁と
の間に冷却水通路を形成する装置が記載されている。For example, in Japanese Patent Publication No. 49-45461, a large number of vertically extending membrane walls and a large number of heat transfer walls are provided parallel to each other with a space between them, and a gap between two adjacent membrane walls is disclosed. A high-temperature raw liquid passageway is provided between the two adjacent heat transfer walls, a cooling water passage is provided between two adjacent heat transfer walls, and a steam space is provided between the adjacent membrane wall and the heat transfer wall for use as a passage for generated steam and distilled water. A device is described that defines cooling water passages between the heat transfer wall and the side walls, respectively, and further defines cooling water passages at both ends of the device body.

〈発明が解決しようとする問題点〉 このような従来装置によれば、高温原液を外部に設置さ
れた熱交換器により加熱したのち装置内へ並列に導入さ
れるため、導入時の放熱による熱効率の低下が避けられ
ないという問題があった。<Problems to be Solved by the Invention> According to such conventional devices, the high-temperature stock solution is heated by a heat exchanger installed outside and then introduced into the device in parallel, so the thermal efficiency due to heat radiation during introduction is low. There was a problem that a decrease in the amount of water was inevitable.

そこで本発明の目的は、保温装置を設けることなく無駄
な放熱が防止されて熱効率のよい膜蒸留装置を提供する
ことである。SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a membrane distillation apparatus that prevents wasteful heat radiation without providing a heat retaining device and has good thermal efficiency.

〈問題点を解決する為の手段〉 本発明の膜蒸留装置は、外管と、冷却用熱媒の通路を形
成するためその外管の内側に設けられた伝熱管と、その
伝熱管の中心部に設けられた加熱器と、原液を透過させ
ずその原液の蒸気を透過させる重合体多孔質膜よりなり
、かつ、上記加熱器表面と上記伝熱管の間に設けられた
膜管と、その膜管と上記加熱器の原液流路の間に原液を
通すための原液導入管および原液導出管と、上記膜管と
上記伝熱管の間の蒸発空間で生成された凝縮液を外部へ
取り出すための凝縮液導出管を有することにより特徴づ
けられる。<Means for Solving the Problems> The membrane distillation apparatus of the present invention includes an outer tube, a heat transfer tube provided inside the outer tube to form a passage for a cooling heat medium, and a center of the heat transfer tube. a heater provided in the section, a membrane tube made of a porous polymer membrane that does not allow the undiluted solution to pass through but allows the vapor of the undiluted solution to pass through, and that is provided between the surface of the heater and the heat transfer tube; A stock solution inlet pipe and a stock solution outlet pipe for passing the stock solution between the membrane tube and the stock solution flow path of the heater, and for taking out the condensed liquid generated in the evaporation space between the membrane tube and the heat transfer tube to the outside. It is characterized by having a condensate discharge pipe.

〈実施例〉 第１図に本発明実施例の縦断面図を示し、第２図にその
横断面図を示す。<Example> FIG. 1 shows a longitudinal cross-sectional view of an example of the present invention, and FIG. 2 shows a cross-sectional view thereof.

外管１は円筒形であって、その下端部に冷却水人口９が
、その上端部に冷却水出口８が、それぞれ設けられ、外
管１の内側に外管と所定の間隔を隔てて伝熱管２が設け
られ、外管との間に冷却用熱媒流路５を形成している。The outer tube 1 has a cylindrical shape, and has a cooling water outlet 9 at its lower end and a cooling water outlet 8 at its upper end. A heat pipe 2 is provided, and a cooling heat medium flow path 5 is formed between the heat pipe 2 and the outer pipe.

伝熱管２の中心部には上端が支持され下端が自由端をな
す棒状の加熱器４が設けられている。この加熱器４と伝
熱管２のほぼ中間に、膜の支持管１３が設けられ、その
支持管１３に膜管３が密着支持されている。この膜管３
で仕切られた内側は原液流路７となり、外側は蒸発空間
６となる。原液流路７の上端に原液導入管１０が、下端
に原液導出管１１がそれぞれ設けられている。また、蒸
発空間６の下端には凝縮液導出管１２が設けられている
。A rod-shaped heater 4 is provided at the center of the heat exchanger tube 2, the upper end of which is supported and the lower end of which is a free end. A membrane support tube 13 is provided approximately midway between the heater 4 and the heat transfer tube 2, and the membrane tube 3 is closely supported by the support tube 13. This membrane tube 3
The inner side partitioned by is a stock solution flow path 7, and the outer side is an evaporation space 6. A stock solution inlet pipe 10 is provided at the upper end of the stock solution channel 7, and a stock solution outlet pipe 11 is provided at the lower end. Further, a condensate outlet pipe 12 is provided at the lower end of the evaporation space 6 .

膜管３を構成する多孔質膜は、高温の原液に対して親和
性を有しないこと、例えば原液が水溶液の場合であれば
疎水性であることが必要であり、更に、原液は透過させ
ないが、その蒸気は透過させる性質を有することが必要
である。更に、原液が加熱されるために、耐熱性も必要
となる。従って、原液が水溶液の場合、ポリテトラフル
オロエチレン樹脂のようなフッ素系樹脂からなる多孔質
膜が耐熱性と疎水性を共に有する点から特に好ましい。The porous membrane constituting the membrane tube 3 needs to have no affinity for high-temperature stock solutions; for example, if the stock solution is an aqueous solution, it must be hydrophobic; furthermore, it must not allow the stock solution to pass through; , it is necessary that the vapor has the property of being permeable. Furthermore, since the stock solution is heated, heat resistance is also required. Therefore, when the stock solution is an aqueous solution, a porous membrane made of a fluororesin such as polytetrafluoroethylene resin is particularly preferred since it has both heat resistance and hydrophobicity.

しかし、例えばポリスルホンやセルロース樹脂のような
親水性樹脂からなる多孔質膜であっても、表面にフッ素
系樹脂やシリコーン樹脂等の溶水性樹脂を被覆して疎水
性の多孔質膜表面を付与するときは、これら樹脂膜も使
用することができる。However, even if the porous membrane is made of a hydrophilic resin such as polysulfone or cellulose resin, the surface of the porous membrane is coated with a water-soluble resin such as a fluororesin or silicone resin to provide a hydrophobic porous membrane surface. In some cases, these resin films can also be used.

伝熱管２は、伝熱性の高い材料、例えば金属からなる薄
肉管が望ましいが、蒸気拡散による熱移動速度より速い
熱伝導度を有する伝熱体であるならプラスチックでもよ
い。The heat exchanger tube 2 is desirably a thin-walled tube made of a material with high heat conductivity, for example metal, but may be made of plastic as long as it is a heat conductor having a thermal conductivity higher than the rate of heat transfer due to vapor diffusion.

膜管３は適宜の支持管１３上に多孔質膜が支持されて形
成されている。この場合、支持管は液体蒸気を透過させ
ることができれば足り、例えばポリアミド、フッ素樹脂
等からなる織布又は不織布管や、セラミック製の多孔質
管が好適に用いられる。The membrane tube 3 is formed by supporting a porous membrane on a suitable support tube 13. In this case, the support tube only needs to be able to transmit liquid vapor, and for example, a woven or nonwoven fabric tube made of polyamide, fluororesin, etc., or a porous tube made of ceramic is preferably used.

本発明の変形実施例として、原液を膜３に効率よく接触
させるため、循環装置又は撹拌装置を設けてもよい。ま
た、支持管１３と伝熱管２等の間にスペーサを設けても
よい。In a variant embodiment of the invention, a circulation device or a stirring device may be provided to bring the stock solution into contact with the membrane 3 efficiently. Further, a spacer may be provided between the support tube 13 and the heat exchanger tube 2, etc.

本発明装置においては、膜管内に保持された原液が加熱
器によって加熱されて、膜管によって原液を阻止しなが
ら、蒸気のみが通過し、蒸気空間を蒸気が拡散し、伝熱
管表面で冷却され、蒸気が凝縮し、凝縮液導出管により
装置外に導かれる。In the device of the present invention, the undiluted solution held in the membrane tube is heated by the heater, and only the vapor passes through while the undiluted solution is blocked by the membrane tube, and the vapor diffuses through the vapor space and is cooled on the surface of the heat transfer tube. , the steam condenses and is led out of the device via a condensate outlet pipe.

また、原液中の溶質は液体と共に膜管により阻止され、
膜管内において濃縮される。従って、例えば、原液とし
て海水を用いるとき、海水の含有する塩類は膜管により
阻止され、水蒸気のみが膜を透過するので、海水は膜管
内に濃縮され、凝縮液側に蒸留水を得ることができる。In addition, the solute in the stock solution is blocked together with the liquid by the membrane tube,
It is concentrated in the membrane tube. Therefore, for example, when seawater is used as the stock solution, the salts contained in the seawater are blocked by the membrane tube, and only water vapor passes through the membrane, so the seawater is concentrated in the membrane tube and distilled water can be obtained on the condensate side. can.

なお、本発明は、海水のように無機塩類を含有する水溶
液のほか、有機物質を含有する溶液の分離濃縮にも適用
することができること勿論である。It goes without saying that the present invention can be applied to the separation and concentration of solutions containing organic substances as well as aqueous solutions containing inorganic salts such as seawater.

〈発明の効果〉 本発明によれば、原液を加熱し、その蒸気のみ膜を透過
させることによって、溶液の分離濃縮を行うので、従来
の逆浸透法と異なり、原液を高圧に加圧する必要がない
うえに、溶質の阻止性能に著しくすぐれている。しかも
、原液流路の中央部に伝熱管が浸漬されているので、熱
の保温装置が不要となり、熱損失が殆どない。<Effects of the Invention> According to the present invention, the solution is separated and concentrated by heating the stock solution and passing only its vapor through the membrane, so unlike the conventional reverse osmosis method, there is no need to pressurize the stock solution to a high pressure. Moreover, it has extremely good solute blocking performance. Moreover, since the heat transfer tube is immersed in the center of the stock solution flow path, a heat insulation device is not required, and there is almost no heat loss.

以下、本発明の試験例を挙げる。Test examples of the present invention are listed below.

〈試験例１〉 第１図に示したように、樹脂製の外管内に、ＦＥＰ織布
にて裏打されたポリテトラフルオロエチレン多孔質膜か
らなる膜管を同軸的に配設し、更にこの膜管外にステン
レス伝熱管を配設して、本発明の装置を構成した。<Test Example 1> As shown in Fig. 1, a membrane tube made of a polytetrafluoroethylene porous membrane lined with FEP woven fabric was coaxially arranged inside a resin outer tube. The apparatus of the present invention was constructed by disposing a stainless steel heat transfer tube outside the membrane tube.

上記多孔質膜は平均孔径０．２μｍの微孔を有し、多孔
度８０％であって、装置における有効膜面積は８９０ｃ
ｍ２であった。The porous membrane has micropores with an average pore diameter of 0.2 μm, a porosity of 80%, and an effective membrane area of 890 cm in the device.
It was m2.

この装置を用い、温度１５°Ｃの冷却水を伝熱管と外管
内に流し、原液として温度８０°Ｃ２導電率１８０μｓ
／ｃｍの水道水を処理したところ、原液中の不純物の除
去により導電率が著しく減少し、導電率１．０μｓ／ｃ
ｍの凝縮水を２６．５ｇ、／ｓｉｎの速度で得ることが
できた。Using this device, cooling water at a temperature of 15°C was flowed into the heat transfer tube and the outer tube, and the temperature was 80°C2 conductivity was 180 μs as a stock solution.
/cm of tap water, the conductivity decreased significantly due to the removal of impurities in the raw solution, and the conductivity decreased to 1.0 μs/cm.
m of condensed water could be obtained at a rate of 26.5 g/sin.

〈試験例２〉 有効膜面積１６８０Ｃ１１２以外は、試験例１と同様の
装置を用い、温度１５°Ｃの冷却水を用い、原液として
温度６０°Ｃ１導電率１８０．ｃｒｓ／ｃｍの水道水を
処理したところ、導電率０．８μｓ／ｃｍの凝縮水を３
２ｇ／ｗｉｎの速度で得ることができた。<Test Example 2> The same equipment as in Test Example 1 was used except for the effective membrane area of 1680C112, cooling water at a temperature of 15°C was used, and the stock solution was heated at a temperature of 60°C and a conductivity of 180. When tap water with a conductivity of crs/cm was treated, condensed water with a conductivity of 0.8 μs/cm was
It could be obtained at a rate of 2g/win.

く試験例３〉 試験例１と同様の装置を用いて、温度１５°Ｃの冷却水
を通し、６０°Ｃの３％食塩水溶液を処理したところ、
９９．９％の排除率で１３．５ｇ／ｗｉｎの速度で凝縮
水を得ることができた。Test Example 3 Using the same equipment as Test Example 1, a 3% saline solution at 60°C was treated by passing cooling water at 15°C.
Condensed water could be obtained at a rate of 13.5 g/win with a rejection rate of 99.9%.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明実施例を示す縦断面図、第２図はその横
断面図である。 １・・・外管 ２・・・伝熱管 ３・・・膜管 ４・・・加熱器 ５・・・冷却用熱媒流路 ６・・・蒸発空間 ７・・・原液流路FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view thereof. 1... Outer tube 2... Heat transfer tube 3... Membrane tube 4... Heater 5... Cooling heat medium channel 6... Evaporation space 7... Stock solution channel

Claims (1)

【特許請求の範囲】[Claims] 外管と、冷却用熱媒の通路を形成するためその外管の内
側に設けられた伝熱管と、その伝熱管の中心部に設けら
れた加熱器と、原液を透過させずその原液の蒸気を透過
させる重合体多孔質膜よりなり、かつ、上記加熱器表面
と上記伝熱管の間に設けられた膜管と、その膜管と上記
加熱器の間の原液流路に原液を通すための原液導入管お
よび原液導出管と、上記膜管と上記伝熱管の間の蒸発空
間で生成された凝縮液を外部へ取り出すための凝縮液導
出管を有する膜蒸留装置。An outer tube, a heat transfer tube provided inside the outer tube to form a passage for the cooling heat medium, a heater provided in the center of the heat transfer tube, and a vapor of the undiluted solution that does not allow the undiluted solution to pass through. a membrane tube that is made of a porous polymer membrane that allows water to permeate therethrough, and is provided between the surface of the heater and the heat transfer tube; A membrane distillation apparatus having a stock solution introduction pipe, a stock solution delivery pipe, and a condensate delivery pipe for taking out the condensate produced in the evaporation space between the membrane tube and the heat transfer tube to the outside.