JP3662337B2 - Method for removing dissolved carbon dioxide - Google Patents
Method for removing dissolved carbon dioxide Download PDFInfo
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- JP3662337B2 JP3662337B2 JP11529096A JP11529096A JP3662337B2 JP 3662337 B2 JP3662337 B2 JP 3662337B2 JP 11529096 A JP11529096 A JP 11529096A JP 11529096 A JP11529096 A JP 11529096A JP 3662337 B2 JP3662337 B2 JP 3662337B2
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- gas
- carbon dioxide
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Description
【０００１】
【発明の属する技術分野】
本発明は、液中の溶存炭酸ガスの除去方法に関するものであり、さらに詳しくは疎水性気体透過膜を介して水溶液中の溶存炭酸ガスを除去する方法の改良に関するものである。
【０００２】
【従来の技術】
半導体製造工程、医薬製造工程、ボイラー等で使用される高純度の純水はイオン交換樹脂及び逆浸透膜等を組み合わせた純水製造装置に原水を供給し製造されている。
原水は、その供給源にもよるが、通常、炭酸ガスを溶存しており、この溶存炭酸ガスは原水のｐＨにより炭酸イオン、重炭酸イオン、炭酸として平衡状態で存在している。そして、その一部がイオン交換樹脂及び逆浸透膜処理では除去されずそのまま透過するので純水の採取量の減少化、純水の純度が向上しない等の要因となっている。
【０００３】
近年、純水製造工程における炭酸ガス等の溶存ガスの除去方法として、疎水性気体透過膜を介して液相部と気相部とが構成された脱気膜モジュールを用い、その気相部を真空ポンプで１０〜３０Ｔｏｒｒ程度の減圧に保持しながら溶存ガスを該気相部に透過させることにより除去する方法が広く採用されている。
ところが、この方法は、本来純水あるいは超純水中に溶存するガス全体を除去するために開発された技術であるため、真空ポンプ、スチームエジェクター等の真空設備を必要とし、装置が大がかりにならざるを得ずコスト的に不利となる欠点を有している。
【０００４】
【発明が解決しようとする課題】
本発明者等は純水製造工程における原水中に溶存する炭酸ガスの脱気膜モジュールを用いた簡便な炭酸ガス除去方法について鋭意検討を加えた結果、従来法では、脱気膜モジュールの気相部を真空ポンプ等で吸引し減圧に維持していたのに対し、むしろ特定の不活性ガス気体を加圧状態で通気させることによって液相部中の溶存気体の分圧の平衡状態に好都合な変化が生じ、液相部中の溶存炭酸ガスが気相部に透過され除去出来ることを知見し、本発明を達成した。
【０００５】
【問題を解決するための手段】
本発明は、疎水性気体透過膜を介して気相部と液相部とが構成された脱気膜モジュールの該液相部に原水を流通させて該原水中の溶存炭酸ガスを該気相部に透過させ除去する方法に於いて、純水製造工程におけるカチオン交換樹脂塔の出口水又は純水製造工程における逆浸透膜装置の透過水を原水とし、且つ該原水を該液相部に通水すると共に該気相部には炭酸ガス以外の不活性ガスを主体とする気体を加圧下に通気し該原水中の溶存炭酸ガスを除去することを特徴とする溶存炭酸ガスの除去方法を要旨とするものである。
【０００６】
【発明の実施の形態】
次に図面を用いて本発明方法を詳細に説明する。図１は本発明を実施するための脱気膜モジュールの概念説明図である。図１中、脱気膜モジュール本体１は疎水性気体透過膜２により液相部４及び気相部３が構成されている。
この脱気膜モジュールに原水入口管５より原水を導入して流通させ、脱気された処理水は処理水出口管６より流出する。その際同時に、不活性気体供給設備（図示せず）より供給される炭酸ガス以外の不活性ガスを主体とする気体を不活性ガス気体注入口７より加圧下で通気することにより、原水中の溶存炭酸ガスを気相部に透過させ、不活性気体出口８より一緒に流出させることにより溶存炭酸ガスの除去を行う。
【０００７】
このように、本発明方法では脱気膜モジュールの気相部３に炭酸ガス以外の不活性ガスを主体とする気体を加圧下に通気することにより、液相部４中の原水の溶存炭酸ガスを効果的に除去し得るものであり、その機構は必ずしも明らかではないが、疎水性気体透過膜で隔てられた気相部と液相部との気体分圧の圧力差、炭酸ガスの比較的高い気体透過性とが互いに関与することにより達せられるものと推察される。つまり、本発明方法に従い、気相部に加圧下に不活性ガス気体を通気するが、その際通気する不活性ガス気体の一部は気体透過膜２を透過して液相部４側へ移動する。液相部４に供給される原水中には、通常、大気中の窒素、酸素、炭酸ガス等の気体が各気体の分圧に応じて飽和溶解度付近まで平衡状態で溶存している。このような原水中に加圧下に通気された不活性ガス気体の一部が膜を透過して移動することにより、原水中の溶存気体の平衡状態に変化が生じ、その結果溶存炭酸ガスが抽気され、抽気された炭酸ガスは他の抽気された気体と共に、気体透過膜２を透過し気相部３へ移動し、液相部に透過しない不活性ガス気体と共に系外に排出することにより溶存炭酸ガスを除去することができるものと推測される。
【０００８】
本発明で採用する炭酸ガス以外の不活性ガスを主体とする気体としては特に限定されるものではなく、窒素ガス、アルゴンガスあるいはその混合気体等を挙げることができるが、これらの気体は、炭酸ガスを０．０５ｖｏｌ％以下含んでいても良く、処理水の所望の水質純度に応じて適宜選定し使用される。また、場合により処理水の目標水質如何によっては空気を用いることも出来る。
この不活性ガス気体のモジュールへの通気条件としては、大気圧の１．０〜２．０倍程度の加圧下に供給するが、モジュールの耐圧強度に応じて適宜調整すれば良い。
また不活性ガス気体は、脱気膜モジュールの原水通水方向と同じである並行方向で通気しても良いが、原水の通気方向とは逆の対向方向に通気するのが効率の面から好ましい。
【０００９】
本発明方法が採用される原水としては、純水製造工程における脱炭酸設備への供給水であり、多塔式純水製造装置のカチオン塔出口水、ＲＯ装置の透過水等が挙げられる。原水の脱気膜モジュール液相部への通水条件は、処理装置の規模、処理原水の水質等により異なるが、通常、流速１〜１００ｍ3／時、通水圧力０．０５〜０．４ＭＰａの範囲で適宜選定される。
気体透過膜としては、酸素、窒素、炭酸ガス等の気体は透過し、水は透過しない疎水性透過膜が用いられる。このような膜の素材としては、ポリプロピレン系、ポリウレタン系のものがあり、市販されているモジュールとしてはセルガードＸ−１０（ヘキスト（株）製）、ＭＪ−５１０（大日本インキ（株）製）、ＭＨＦ １７０４（三菱レイヨン（株）製）等がある。本発明方法に於いては、これら市販のモジュールを適宜用いて溶存炭酸ガスを除去することができる。
【００１０】
溶存炭酸ガスが極めて少ない高い水質の処理水を得たい場合には、脱気膜モジュールを複数個直列に連結し、各モジュールに於いて本発明方法を採用することにより溶存炭酸ガスを極めて微量にすることができる。
【００１１】
【発明の効果】
本発明方法では、脱気膜モジュールを用いて原水中の溶存炭酸ガスを除去するにあたり、真空源を用いずに炭酸ガスが除去できるので、装置の小型化が可能となり、操作性も簡便となり、ランニングコストも減少させることができるので、工業的に利するところ大である。
【００１２】
【実施例】
次に、本発明を実施例によりさらに具体的に説明するが、本発明はその要旨を越えない限り以下の実施例に限定されるものではない。
【００１３】
実施例 １
表−１に示すような組成を有する逆浸透膜処理水を原水として脱気膜モジュール セルガードＸ−１０（ヘキスト（株）製）に通水し、本発明方法により溶存炭酸ガスを除去した。その際の脱気膜モジュールの運転条件は、原水通水流量 １．２ｍ3／時、通水圧力０．２ＭＰａであり、不活性ガス気体としては窒素を用い、通気圧力０．１１ＭＰａ，通気流量 ５Ｎｍ3／分で通気した。
上記の条件で溶存炭酸ガスの除去処理をして得られた処理水を、強酸性陽イオン交換樹脂 ダイヤイオンＳＫ１Ｂ（ダイヤイオンは三菱化学（株）の登録商標）４リットルと強塩基性陰イオン交換樹脂ダイヤイオンＳＡ１０Ａ、６リットルからなる混合床に通水した。その結果を図２に示した。尚、図中、縦軸は電気伝導度（μＳ／ｃｍ）、横軸は処理水量（ｍ3）を表す。
【００１４】
【表１】
実施例 ２
実施例１に於いて、不活性ガス気体として空気を通気した外は全くの同一条件で実験を行った。結果を図２に示した。
【００１６】
比較例 １
実施例１に於いて、原水中の溶存炭酸ガスの除去処理を行わずにイオン交換樹脂混合床に通水した。その結果は図２のようであった。
【図面の簡単な説明】
【図１】本発明を実施するための脱気膜モジュールの概念を示す図である。
【図２】本発明方法に従い溶存炭酸ガスの脱処理した処理水量と純度の関係を示し、横軸は処理水量（ｍ3）、縦軸は電気伝導度（μＳ／ｃｍ）を表す。
【符号の説明】
１ 脱気膜モジュール本体
２ 疎水性気体透過膜
３ 気相部
４ 液相部
５ 原水導入口管
６ 処理水出口管
７ 不活性ガス気体注入口
８ 不活性ガス気体出口[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for removing dissolved carbon dioxide in a liquid, and more particularly, to an improvement in a method for removing dissolved carbon dioxide in an aqueous solution through a hydrophobic gas permeable membrane.
[0002]
[Prior art]
High-purity pure water used in semiconductor manufacturing processes, pharmaceutical manufacturing processes, boilers, and the like is manufactured by supplying raw water to a pure water manufacturing apparatus that combines an ion exchange resin and a reverse osmosis membrane.
Although raw water depends on its supply source, carbon dioxide gas is usually dissolved, and this dissolved carbon dioxide gas exists in an equilibrium state as carbonate ions, bicarbonate ions, and carbonic acid depending on the pH of the raw water. And since a part of it is not removed by the ion exchange resin and reverse osmosis membrane treatment and permeates as it is, it causes factors such as a decrease in the amount of pure water collected and an increase in the purity of pure water.
[0003]
In recent years, as a method for removing dissolved gas such as carbon dioxide in a pure water production process, a degassing membrane module in which a liquid phase portion and a gas phase portion are configured via a hydrophobic gas permeable membrane is used. A method of removing dissolved gas by permeating the gas phase portion while maintaining a reduced pressure of about 10 to 30 Torr with a vacuum pump is widely adopted.
However, since this method is originally developed to remove the entire gas dissolved in pure water or ultrapure water, it requires vacuum equipment such as a vacuum pump and a steam ejector, and the equipment becomes large. Inevitably, it has the disadvantage of being disadvantageous in terms of cost.
[0004]
[Problems to be solved by the invention]
As a result of intensive studies on a simple carbon dioxide gas removal method using a carbon dioxide gas degassing membrane module dissolved in raw water in the pure water production process, the present inventors have found that the conventional method uses a gas phase of the degassing membrane module. The part was sucked with a vacuum pump or the like and maintained at a reduced pressure, but rather it was convenient for the equilibrium state of the partial pressure of the dissolved gas in the liquid phase part by ventilating a specific inert gas gas under pressure. A change occurred, and it was found that the dissolved carbon dioxide gas in the liquid phase part was permeated into the gas phase part and could be removed, thereby achieving the present invention.
[0005]
[Means for solving problems]
In the present invention, raw water is circulated to the liquid phase part of a degassing membrane module in which a gas phase part and a liquid phase part are configured via a hydrophobic gas permeable membrane, and dissolved carbon dioxide gas in the raw water is supplied to the gas phase. In the method of permeating through and removing the water , the outlet water of the cation exchange resin tower in the pure water production process or the permeated water of the reverse osmosis membrane device in the pure water production process is used as raw water, and the raw water is passed through the liquid phase part. A summary of a method for removing dissolved carbon dioxide, characterized in that, while water is added, a gas mainly composed of an inert gas other than carbon dioxide is passed through the gas phase portion under pressure to remove the dissolved carbon dioxide in the raw water. It is what.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Next, the method of the present invention will be described in detail with reference to the drawings. FIG. 1 is a conceptual explanatory diagram of a degassing membrane module for carrying out the present invention. In FIG. 1, a degassing
Raw water is introduced into the degassing membrane module from the raw
[0007]
As described above, in the method of the present invention, the dissolved carbon dioxide gas in the raw water in the liquid phase portion 4 is formed by ventilating the
[0008]
The gas mainly composed of an inert gas other than the carbon dioxide gas used in the present invention is not particularly limited, and examples thereof include nitrogen gas, argon gas, or a mixed gas thereof. The gas may contain 0.05 vol% or less, and is appropriately selected and used depending on the desired water purity of the treated water. In some cases, air can be used depending on the target water quality of the treated water.
The inert gas gas is supplied to the module under a pressure of about 1.0 to 2.0 times the atmospheric pressure, but may be adjusted as appropriate according to the pressure resistance of the module.
Further, the inert gas gas may be ventilated in a parallel direction that is the same as the raw water passage direction of the degassing membrane module, but it is preferable from the aspect of efficiency to vent the opposite direction opposite to the raw water passage direction. .
[0009]
The raw water to which the method of the present invention is adopted is water supplied to the decarbonation facility in the pure water production process, and examples thereof include cation tower outlet water of a multi-column pure water production apparatus and permeated water of an RO apparatus. The conditions for water flow to the liquid phase part of the raw water degassing membrane module vary depending on the scale of the treatment apparatus, the quality of the treated raw water, etc., but usually a flow rate of 1 to 100 m 3 / hour, a water flow pressure of 0.05 to 0.4 MPa. It is appropriately selected within the range.
As the gas permeable membrane, a hydrophobic permeable membrane that allows gas such as oxygen, nitrogen, and carbon dioxide to permeate but does not permeate water is used. As materials for such a film, there are polypropylene type and polyurethane type, and commercially available modules include Celgard X-10 (manufactured by Hoechst Co.), MJ-510 (manufactured by Dainippon Ink Co., Ltd.). And MHF 1704 (manufactured by Mitsubishi Rayon Co., Ltd.). In the method of the present invention, dissolved carbon dioxide gas can be removed using these commercially available modules as appropriate.
[0010]
If you want to obtain high-quality treated water with very little dissolved carbon dioxide, connect a plurality of degassing membrane modules in series and use the method of the present invention in each module to make very little dissolved carbon dioxide. can do.
[0011]
【The invention's effect】
In the method of the present invention, when removing the dissolved carbon dioxide gas in the raw water using the degassing membrane module, the carbon dioxide gas can be removed without using a vacuum source, so that the apparatus can be miniaturized and the operability becomes simple, Since the running cost can be reduced, it is great for industrial reasons.
[0012]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example, unless the summary is exceeded.
[0013]
Example 1
Reverse osmosis membrane treated water having a composition as shown in Table 1 was used as raw water and passed through a deaeration membrane module Celgard X-10 (manufactured by Hoechst), and dissolved carbon dioxide gas was removed by the method of the present invention. The operating conditions of the degassing membrane module at that time are as follows: raw water flow rate 1.2 m 3 / hour, water flow pressure 0.2 MPa, nitrogen as the inert gas gas, aeration pressure 0.11 MPa, aeration flow rate Aeration was performed at 5 Nm 3 / min.
The treated water obtained by removing the dissolved carbon dioxide under the above conditions is obtained by using 4 liters of strongly acidic cation exchange resin Diaion SK1B (Diaion is a registered trademark of Mitsubishi Chemical Corporation) and a strongly basic anion. Water was passed through a mixed bed consisting of 6 liters of exchange resin Diaion SA10A. The results are shown in FIG. In the figure, the vertical axis represents electric conductivity (μS / cm), and the horizontal axis represents the amount of treated water (m 3 ).
[0014]
[Table 1]
Example 2
In Example 1, the experiment was performed under exactly the same conditions except that air was passed as an inert gas gas. The results are shown in FIG.
[0016]
Comparative Example 1
In Example 1, water was passed through the ion-exchange resin mixed bed without removing the dissolved carbon dioxide in the raw water. The result was as shown in FIG.
[Brief description of the drawings]
FIG. 1 is a diagram showing a concept of a deaeration membrane module for carrying out the present invention.
FIG. 2 shows the relationship between the amount of treated water obtained by detreatment of dissolved carbon dioxide gas and the purity according to the method of the present invention, the horizontal axis represents the amount of treated water (m 3 ), and the vertical axis represents the electric conductivity (μS / cm).
[Explanation of symbols]
DESCRIPTION OF
Claims (4)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11529096A JP3662337B2 (en) | 1996-04-15 | 1996-04-15 | Method for removing dissolved carbon dioxide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11529096A JP3662337B2 (en) | 1996-04-15 | 1996-04-15 | Method for removing dissolved carbon dioxide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09276603A JPH09276603A (en) | 1997-10-28 |
| JP3662337B2 true JP3662337B2 (en) | 2005-06-22 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11529096A Expired - Fee Related JP3662337B2 (en) | 1996-04-15 | 1996-04-15 | Method for removing dissolved carbon dioxide |
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| Country | Link |
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| JP (1) | JP3662337B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3617468B2 (en) * | 2001-04-12 | 2005-02-02 | 栗田工業株式会社 | Decarbonation method and pure water production method |
| CN104069651A (en) * | 2013-03-25 | 2014-10-01 | 上海和鹰机电科技股份有限公司 | Steam treatment device and water cutting machine including same |
| AT16829U1 (en) * | 2019-10-30 | 2020-10-15 | Bvs Wassertechnik Gmbh | Membrane degassing device for separating gases from a fluid flow |
-
1996
- 1996-04-15 JP JP11529096A patent/JP3662337B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09276603A (en) | 1997-10-28 |
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