JP3985497B2

JP3985497B2 - Electric deionizer

Info

Publication number: JP3985497B2
Application number: JP2001334950A
Authority: JP
Inventors: 昌之三輪; 伸佐藤
Original assignee: Kurita Water Industries Ltd
Current assignee: Kurita Water Industries Ltd
Priority date: 2001-10-31
Filing date: 2001-10-31
Publication date: 2007-10-03
Anticipated expiration: 2021-10-31
Also published as: JP2003136063A

Description

【０００１】
【発明の属する技術分野】
本発明は電気式脱イオン装置に係り、詳しくは単位時間当りの脱イオン水（生産水）の生産水量が少ない場合に好適な電気式脱イオン装置に関する。
【０００２】
【従来の技術】
従来の電気式脱イオン装置は、電極（陽極と陰極）同士の間に複数のカチオン交換膜とアニオン交換膜とを交互に配列して脱塩室と濃縮室とを交互に形成し、脱塩室にイオン交換樹脂を充填した構成を有する。この電気式脱イオン装置にあっては陽極、陰極間に電圧を印加しながら脱塩室に被処理水を流入させると共に、濃縮室に濃縮水を流通させて被処理水中の不純物イオンを除去し、脱イオン水を製造する。
【０００３】
【発明が解決しようとする課題】
従来の電気式脱イオン装置は、陰極と陽極との間に複数の脱塩室と濃縮室とを交互に形成したものであるため、陰極と陽極との間の電気抵抗が大きく、両極間の印加電圧が高い。また、原水中のＣａ^２＋及び炭酸成分（ＣＯ_２，ＨＣＯ_３ ⁻）に起因する炭酸カルシウムスケールが濃縮室のイオン交換膜面にしばしば生じていた。
【０００４】
本発明は、生産水量が少ない場合に採用するのに好適な、電極間の印加電圧が低く、また、スケールが発生しにくい電気式脱イオン装置を提供することを目的とする。
【０００５】
【課題を解決するための手段】
本発明（請求項１）の電気式脱イオン装置は、陰極と陽極との間にカチオン交換膜とアニオン交換膜とが１枚ずつ配置され、該陰極とカチオン交換膜との間に濃縮室兼陰極室が設けられ、該陽極とアニオン交換膜との間に濃縮室兼陽極室が設けられ、該カチオン交換膜とアニオン交換膜との間に脱塩室が設けられ、該濃縮室兼陽極室内及び濃縮室兼陰極室内にそれぞれカチオン交換樹脂が充填され、該脱塩室内にイオン交換体が充填されてなるものである。
【０００６】
本発明（請求項２）の電気式脱イオン装置は、上記請求項１の電気式脱イオン装置の濃縮室兼電極室内に導電体を充填する代わりに、陽極板及び陰極板に電極水を流す通水路を設けると共に、該陽極板と陰極板がイオン交換膜と接するようにしたものである。
【０００７】
即ち、本発明（請求項２）の電気式脱イオン装置は、陰極板と陽極板との間にカチオン交換膜とアニオン交換膜とが１枚ずつ配置され、該陰極板とカチオン交換膜との間に濃縮室兼陰極室が設けられ、該陽極板とアニオン交換膜との間に濃縮室兼陽極室が設けられ、該カチオン交換膜とアニオン交換膜との間に脱塩室が設けられ、該陰極板及び陽極板が電極水の通水路を有し、該陰極板がカチオン交換膜に接し、該陽極板が該アニオン交換膜と接していることを特徴とするものである。
【０００８】
かかる本発明（請求項１，２）の電気式脱イオン装置は、脱塩室が１室であり、且つこの脱塩室の両側にはそれぞれ陽極室を兼ねた濃縮室と陰極室を兼ねた濃縮室とが配置されているため、電極間距離が小さく、電極間の印加電圧が低い。本発明では、脱塩室が１室であり、単位時間当たりの生産水量が少ないが、小規模実験用、小型燃料電池用などには十分に実用することができる。
【０００９】
本発明の電気式脱イオン装置は、好ましくは、脱塩室内を区画部材によって多数の小室に区画し、各小室にイオン交換体を充填する。この各小室に臨む区画部材の少なくとも一部は、脱塩室内の平均的な水の流れ方向に対して傾斜しており、この傾斜した部分は、水は通過させるが、イオン交換樹脂は通過させない構造となっている。この脱塩室内に流入した水の少なくとも一部は、平均的な水の流れ方向に対し斜め方向に流れるようになり、脱塩室内の全体に分散して流れる。従って、水とイオン交換樹脂との接触効率が向上し、脱イオン特性が向上する。
【００１０】
この小室を平均的な水の流れ方向及びこれと直交方向のいずれにおいても膜面に沿って複数個配置することにより、（例えば縦横に多数配置することにより、）水とイオン交換樹脂との接触効率がきわめて高いものとなる。また、各小室内の上下方向の高さが小さくなり、イオン交換樹脂が局部的に圧縮されにくくなる。従って、小室に隙間が生じることがなく、イオン交換樹脂の充填密度が高い。
【００１１】
この小室は、イオン交換膜面に投影した形状が六角形又は四角形であってもよい。六角形の場合には、１対の平行な辺が平均的な水の流れ方向となるように各小室を配置するのが好ましい。四角形の場合には、各辺が平均的な水の流れ方向に対し傾斜するように配置する。この様な構造にすることによって、脱塩効率が高まるため、脱塩室への高流速通水が可能となり、脱塩室１室当たりの処理流量を多くすることができる。
【００１２】
１つの小室内に１種類のイオン交換特性のイオン交換体のみを充填してもよく、複数種類のイオン交換特性のイオン交換体を充填してもよい。例えば１つの小室内にアニオン交換体と両性イオン交換体とを混合して充填してもよい。
【００１３】
本発明の電気式脱イオン装置においては、脱塩室へ流入する原水流路から原水の分岐流路が分岐され、原水の一部が該分岐流路を介して濃縮室兼陽極室及び濃縮室兼陰極室へそれぞれ独立して流されるようにしてもよい。これにより、脱塩室から各濃縮室兼電極室へ移動したイオン種が会合しないようになるため、電極室でのスケール生成が防止される。
【００１４】
【発明の実施の形態】
以下、図面を参照して実施の形態について説明する。図１は実施の形態に係る電気式脱イオン装置の概略的な縦断面図である。図２は区画部材を脱塩室内に配置した電気式脱イオン装置の分解斜視図、図３は区画部材の斜視図、図４は区画部材の分解図、図５は区画部材の通水状況説明図である。
【００１５】
図１に示す通り、陰極１と陽極２との間にカチオン交換膜３とアニオン交換膜４とを１枚ずつ配置し、陰極１とカチオン交換膜３との間に濃縮室兼陰極室５を形成し、陽極２とアニオン交換膜４との間に濃縮室兼陽極室６を形成し、カチオン交換膜３とアニオン交換膜４との間に脱塩室７を形成している。濃縮室兼用の陰極室５及び陽極室６にはそれぞれカチオン交換樹脂８が充填されている。この陰極室５及び陽極室６に充填されるイオン交換樹脂は、アニオン交換樹脂やアニオン交換樹脂とカチオン交換樹脂を混合したものであってもよいが、樹脂の強度の点からはカチオン交換樹脂を用いるのが好ましい。脱塩室７にはカチオン交換樹脂８とアニオン交換樹脂９とが混合状態にて充填されている。
【００１６】
なお、本発明の電気式脱イオン装置においては、濃縮室兼陰極室及び濃縮室兼陽極室内の別の形態として、濃縮室兼用の両電極室にイオン交換樹脂を充填する代わりに図６に示すように陰極板８０及び陽極板９０を電極水が通水可能な構造とし、陰極板８０がカチオン交換膜３に接し、陽極板９０がアニオン交換膜４と接するように配置してもよい。これによって、両濃縮室兼電極室内の電気抵抗が小さくなり、低い印加電圧でも効率的に脱イオン処理を行うことが可能となる。このような電極板８０，９０は、厚み方向に貫通する多数の開口を有した孔明き板を複数枚積層して隣接する孔明き板の孔同士を部分的に重なり合わせることにより、形成することができる。
【００１７】
図１〜５において、陰極１と陽極２との間に電圧を印加した状態にて原水を脱塩室７に導入し、脱イオン水として取り出す。陰極電極水を濃縮室兼陰極室５に流通させ、陽極電極水を濃縮室兼陽極室６に流通させる。原水中のカチオンはカチオン交換膜３を透過し、陰極電極水に混入して排出される。原水中のアニオンはアニオン交換膜４を透過して陽極電極水に混入し、排出される。
【００１８】
この電気式脱イオン装置にあっては、陰極１と陽極２との間にそれぞれ１個の脱塩室７、濃縮室兼陽極室６及び濃縮室兼陰極室５のみが配置されており、陰極１と陽極２との距離が小さい。そのため、電極１，２間の印加電圧が低くても十分に電極１，２間に電流を流して脱イオン処理することができる。
【００１９】
また、本発明では脱塩室内のＣａ^２＋は濃縮室兼陰極室へ、ＨＣＯ_３ ⁻は濃縮室兼陽極室へそれぞれ移動し、Ｃａ^２＋とＨＣＯ_３ ⁻とが同一の濃縮室兼電極室で会合しないため、スケールが発生しにくい。
【００２０】
なお、電極室が濃縮室を兼ねていることから、電極水の電気伝導度が高い。これによっても、電極１，２間の印加電圧が低くても電極１，２間に十分に電流を流すことが可能となる。
【００２１】
電極室兼濃縮室５，６での通水方向は、脱塩室と並流通水でも向流通水でもよいが、上昇流通水であることが望ましい。これは、各電極室兼濃縮室５，６には、直流電流によってＨ_２，Ｏ_２等の気体が発生するので、上昇流で通水し気体の排出を促進させ偏流を防ぐためである。
【００２２】
本発明において、濃縮室兼陽極室及び濃縮室兼陰極室へ通水される電極水としては、原水を分岐してそれぞれの濃縮室兼電極室へ独立して通水するのが望ましい。この通水方式によれば、従来、一方の電極室流出水を他方の電極水として使用するのと異なり、脱塩室から各濃縮室兼電極室へ移動したイオン種が会合することがないため、スケールが発生しにくくなる。
【００２３】
次に、図２〜５を参照して、脱塩室内に区画部材を配置して脱塩室内に多数の小室を形成した電気式脱イオン装置について説明する。
【００２４】
陰極側のエンドプレート１１に沿って陰極電極板１２が配置され、この陰極電極板１２の周縁部に枠状の濃縮室兼陰極室形成用枠状フレーム１３が重ね合わされている。この枠状フレーム１３の上にカチオン交換膜１４が重ね合わされ、このカチオン交換膜１４の上に脱塩室形成用の枠状フレーム２０、アニオン交換膜１５及び濃縮室形成用の枠状フレーム１７がこの順に重ね合わされている。アニオン交換膜１５に対し濃縮室兼陽極室形成用の枠状フレーム１６を介して陽極電極板１７が重ね合わされ、その上に陽極側エンドプレート１８が重ね合わされて積層体とされる。この積層体はボルト等によって締め付けられる。
【００２５】
枠状フレーム２０の内側が脱塩室となっている。この脱塩室に区画部材２１が設けられており、区画部材２１内にアニオン交換樹脂とカチオン交換樹脂との混合物よりなるイオン交換樹脂２３が充填されている。
【００２６】
濃縮室兼陰極室用フレーム１３の内側スペースが濃縮室兼陰極室３０となっており、濃縮室兼陽極室用フレーム１６の内側が濃縮室兼陽極室４０となっている。この濃縮室兼用の陰極室３０及び陽極室４０には導電体としてカチオン交換樹脂８が充填されている。
【００２７】
濃縮室兼陰極室３０に陰極電極水を流通させるために、エンドプレート１１とフレーム１３にそれぞれ透孔３１，３２，３５，３６が設けられると共に、フレーム１３にスリット３３，３４が設けられている。
【００２８】
透孔３１，３２は互いに重なり合い、透孔３５，３６も互い重なり合う。フレーム１３の透孔３２，３５はそれぞれスリット３３，３４を介して濃縮室兼陰極室３０に連通している。
【００２９】
陰極電極水は、透孔３１，３２、スリット３３、濃縮室兼陰極室３０、スリット３４、透孔３５，３６の順に流れ、濃縮水兼陰極電極水として流出する。
【００３０】
濃縮室兼陽極室４０に陽極電極水を流通させるために、エンドプレート１８とフレーム１６にそれぞれ透孔４１，４２，４５，４６が設けられると共に、フレーム１６にスリット４３，４４が設けられている。
【００３１】
透孔４１，４２は互いに重なり合い、透孔４５，４６も互い重なり合う。フレーム１６の透孔４２，４５はそれぞれスリット４３，４４を介して濃縮室兼陽極室４０に連通している。
【００３２】
陽極電極水は、透孔４１，４２、スリット４３、濃縮室兼陽極室４０、スリット４４、透孔４５，４６の順に流れ、濃縮水兼陽極電極水として流出する。
【００３３】
フレーム２０の内側の脱塩室に原水を流通させるために、エンドプレート１８、アニオン交換膜１５とフレーム１６，２０にそれぞれ透孔５１，５２，５３，５４，５７，５８，５９，６０が設けられる（符号５８，５９は図示なし。）と共に、フレーム２０にスリット５５，５６が設けられている。透孔５１，６０はエンドプレート１８に設けられ、透孔５４，５７はフレーム２０に設けられ、透孔５２，５９はフレーム１６に設けられ、透孔５３，５８はアニオン交換膜１５に設けられている。
【００３４】
透孔５１〜５４は互いに重なり合い、透孔５７〜６０も互いに重なり合う。フレーム２０の透孔５４，５７はそれぞれスリット５５，５６を介して脱塩室に連通している。
【００３５】
原水は、透孔５１，５２，５３，５４、スリット５５、脱塩室、スリット５６、透孔５７〜６０の順に流れ、脱イオン水（生産水）として流出する。
【００３６】
上記の脱塩室用フレーム２０は上下方向に長い長方形状のものである。このフレーム２０内に配置された区画部材２１は六角形のハニカム形状のものであり、小室２２は上下左右に多数配置されている。各小室２２の１対の側辺がフレーム２０の長手方向即ち上下方向となるように配置されている。
【００３７】
この区画部材２１は、予め一体成形されたものであってもよく、複数の部材を組み合わせたものであってもよい。例えば図４のようにジグザグ状の屈曲板７０の長手方向面７１同士を連結することにより構成される。この屈曲板７０は、長手方向面７１に対し１２０゜の角度で連なる通水性の斜向面７２，７３を備えている。長手方向面７１同士を連結するには例えば接着剤を用いることができる。この屈曲板７０は、水は通過させるがイオン交換樹脂は通過させない材料、例えば織布、不織布、メッシュ、多孔質材などにより構成されている。この屈曲板７０は耐酸性及び耐アルカリ性を有した合成樹脂又は金属により剛性を有するように形成されるのが好ましい。長手方向面７１は通水性を有していてもよく、有していなくてもよい。
【００３８】
区画部材２１はフレーム２０に嵌め込まれてもよい。また、フレーム２０の片面側に透水性シート又はメッシュを張設し、これに区画部材を接着してもよい。
【００３９】
透孔５４から透孔５５を介して脱塩室に流入した原水は、図５の通り小室２２を囲む区画部材２１を通過して隣接する小室２２に流れ込み、徐々に下方に流れ、この間に脱イオン処理を受ける。そして、遂には脱塩室の下部に達し、スリット５６及び透孔５７〜６０を通り、脱塩水として電気的脱イオン装置外に取り出される。
【００４０】
この脱塩室における平均的な水の流れ方向は、原水流入用の透孔５４及びスリット５５がフレーム２０の上部に存在し、脱塩水取出用のスリット５６及び透孔５７がフレーム２０の下部に存在するところから、上から下に向う鉛直方向となっている。この平均的な水の流れ方向に対し小室の上部及び下部が傾斜しているので、被処理水は１つの小室２２から左及び右側の小室２２へ斜めに分かれて流下するようになる。このため、被処理水が各小室２２にほぼ均等に分散して流れるようになり、被処理水とイオン交換樹脂２３との接触効率が良好なものとなる。
【００４１】
この脱塩室にあっては、小室２２が比較的小さく、イオン交換体の自重及び水圧によって各小室２２内においてイオン交換体に対し加えられる下向きの圧力が小さい。従って、いずれの小室２２内においてもイオン交換体が圧縮されることがなく、イオン交換体が小室内の下部において局部的に圧密化されることがない。この実施の形態では、各小室２２に充填したイオン交換樹脂は、アニオン交換樹脂とカチオン交換樹脂との混合物であるが、次の(i)〜(iii)のいずれかでもよい。
(i) すべての小室にアニオン交換樹脂、カチオン交換樹脂、両性イオン交換樹脂のうち１種類のものを充填する。
(ii) すべての小室にアニオン交換樹脂、カチオン交換樹脂及び両性イオン交換樹脂の２又は３の混合物を充填する。混合比、混合種はすべて共通であってもよく、一部又はすべての小室において異なっていてもよい。
(iii) 一部の小室にアニオン交換樹脂を充填し、他の一部の小室にカチオン交換樹脂を充填し、残りの小室にアニオン交換樹脂とカチオン交換樹脂の混合物又は両性イオン交換樹脂を充填する。
【００４２】
なお、(ii)，(iii)の場合、原水のアニオン、カチオン比率に応じ、アニオン交換樹脂を充填する小室、及びカチオン交換樹脂を充填する小室の数を調整してもよい。
【００４３】
この電気式脱イオン装置の脱塩室のＬＶは１５〜４５ｍ／ｈ、ＳＶは８０〜２８０Ｈｒ^−１程度が好ましい。
【００４４】
この図２〜５の電気式脱イオン装置も、陰極・陽極間の積層室数が少ないので、電気抵抗が小さく、少ない電圧で、必要量の電流を流すことができる。
【００４５】
また、脱塩室内にハニカム状構造体を充填しているので、高純度の処理水を得ることができる。
【００４６】
【発明の効果】
以上の通り、本発明の電気式脱イオン装置は、陰極と陽極との間にそれぞれ１個の脱塩室、濃縮室兼陰極室及び濃縮室兼陽極室を配置したものであり、電極間距離が小さく、また電極室と濃縮室とが兼用され電極水が高電気伝導度の濃縮水となっているため、電極間の印加電圧を低くしても必要量の電流を流し、十分に脱イオン処理することができる。また、スケール成分である極性の異なるイオン種がそれぞれの濃縮室兼電極室へ移動し、それらが会合しないため、スケールが発生しにくい。
【００４７】
本発明の電気式脱イオン装置は、小規模実験室用、小型燃料電池用など生産水量が少量の用途にきわめて好適である。
【図面の簡単な説明】
【図１】実施の形態に係る電気式脱イオン装置の概略的な縦断面図である。
【図２】区画部材を脱塩室内に配置した電気式脱イオン装置の分解斜視図である。
【図３】区画部材の斜視図である。
【図４】区画部材の分解図である。
【図５】区画部材の通水状況説明図である。
【図６】別の実施の形態に係る電気式脱イオン装置の概略的な縦断面図である。
【符号の説明】
１陰極
２陽極
３カチオン交換膜
４アニオン交換膜
５濃縮室兼陰極室
６濃縮室兼陽極室
７脱塩室
８カチオン交換樹脂
９アニオン交換樹脂
２０フレーム
２１区画部材
２２小室
２３アニオン交換樹脂とカチオン交換樹脂との混合イオン交換樹脂
８０陰極板
９０陽極板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric deionization apparatus, and more particularly to an electric deionization apparatus suitable when the amount of deionized water (production water) produced per unit time is small.
[0002]
[Prior art]
A conventional electric deionization apparatus alternately forms a plurality of cation exchange membranes and anion exchange membranes between electrodes (anode and cathode) to alternately form a desalting chamber and a concentrating chamber. The chamber is filled with ion exchange resin. In this electric deionization apparatus, water to be treated is allowed to flow into the demineralization chamber while applying a voltage between the anode and the cathode, and the concentrated water is circulated through the concentration chamber to remove impurity ions in the water to be treated. To produce deionized water.
[0003]
[Problems to be solved by the invention]
Since the conventional electric deionization apparatus is formed by alternately forming a plurality of demineralization chambers and concentration chambers between the cathode and the anode, the electric resistance between the cathode and the anode is large, and between the two electrodes. Applied voltage is high. In addition, calcium carbonate scale caused by Ca ²⁺ and carbonic acid components (CO ₂ , HCO ₃ ⁻ ) in the raw water often occurred on the ion exchange membrane surface of the concentration chamber.
[0004]
An object of the present invention is to provide an electric deionization apparatus that is suitable for use when the amount of produced water is small and that is low in applied voltage between electrodes and is less likely to cause scale.
[0005]
[Means for Solving the Problems]
In the electric deionization apparatus of the present invention (Claim 1), one cation exchange membrane and one anion exchange membrane are disposed between the cathode and the anode, and the concentration chamber serves as a space between the cathode and the cation exchange membrane. A cathode chamber is provided, a concentration chamber / anode chamber is provided between the anode and the anion exchange membrane, a desalting chamber is provided between the cation exchange membrane and the anion exchange membrane, and the concentration chamber / anode chamber is provided. In addition, the concentration chamber / cathode chamber is filled with a cation exchange resin , and the demineralization chamber is filled with an ion exchanger.
[0006]
The electric deionization apparatus of the present invention (Claim 2) allows the electrode water to flow through the anode plate and the cathode plate instead of filling the concentrating chamber / electrode chamber of the electric deionization apparatus according to Claim 1 with a conductor. A water passage is provided, and the anode plate and the cathode plate are in contact with the ion exchange membrane.
[0007]
That is, in the electric deionization apparatus of the present invention (Claim 2), one cation exchange membrane and one anion exchange membrane are arranged between the cathode plate and the anode plate, and the cathode plate and the cation exchange membrane are A concentration chamber / cathode chamber is provided between the anode plate and the anion exchange membrane, a concentration chamber / anode chamber is provided, and a desalting chamber is provided between the cation exchange membrane and the anion exchange membrane, The cathode plate and the anode plate have a water passage for electrode water, the cathode plate is in contact with the cation exchange membrane, and the anode plate is in contact with the anion exchange membrane.
[0008]
In the electric deionization apparatus of the present invention (Claims 1 and 2), there is one demineralization chamber, and both sides of the demineralization chamber also function as a concentrating chamber and a cathode chamber, respectively. Since the concentrating chamber is arranged, the distance between the electrodes is small and the applied voltage between the electrodes is low. In the present invention, the desalination chamber is one chamber, and the amount of produced water per unit time is small, but it can be sufficiently put into practical use for small-scale experiments, small fuel cells, and the like.
[0009]
In the electric deionization apparatus of the present invention, the demineralization chamber is preferably partitioned into a number of small chambers by a partition member, and each small chamber is filled with an ion exchanger. At least a part of the partition members facing each of the small chambers is inclined with respect to the average water flow direction in the desalting chamber, and this inclined portion allows water to pass but does not allow ion exchange resin to pass. It has a structure. At least a portion of the water that has flowed into the desalting chamber flows in an oblique direction with respect to the average water flow direction, and flows in a distributed manner throughout the desalting chamber. Therefore, the contact efficiency between water and the ion exchange resin is improved, and the deionization characteristics are improved.
[0010]
By arranging a plurality of these chambers along the membrane surface in both the average water flow direction and the direction orthogonal thereto, contact between water and the ion exchange resin (for example, by arranging a large number in the vertical and horizontal directions) The efficiency is extremely high. In addition, the vertical height of each small chamber is reduced, and the ion exchange resin is not locally compressed. Therefore, no gap is generated in the small chamber, and the packing density of the ion exchange resin is high.
[0011]
The small chamber may have a hexagonal shape or a quadrangular shape projected onto the surface of the ion exchange membrane. In the case of a hexagon, it is preferable to arrange each chamber so that a pair of parallel sides is an average water flow direction. In the case of a quadrangle, each side is arranged so as to be inclined with respect to the average water flow direction. By adopting such a structure, the desalting efficiency is increased, so that a high flow rate water can be passed to the desalting chamber, and the treatment flow rate per one desalting chamber can be increased.
[0012]
One small chamber may be filled with only one type of ion exchanger having ion exchange characteristics, or a plurality of types of ion exchangers having ion exchange characteristics may be filled. For example, an anion exchanger and an amphoteric ion exchanger may be mixed and filled in one small chamber.
[0013]
In the electric deionization apparatus of the present invention, the branch flow path of the raw water is branched from the raw water flow path that flows into the demineralization chamber, and a part of the raw water passes through the branch flow path to the concentration chamber / anode chamber and the concentration chamber. Re and cathode compartment navel Resolution may be independent to flows so. Thus, the ion species moved to the concentrating chambers and the electrode chambers from the desalting is not associated, scale formation at the electrode chamber can be prevented.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a schematic longitudinal sectional view of an electric deionization apparatus according to an embodiment. 2 is an exploded perspective view of an electric deionization apparatus in which a partition member is disposed in a demineralization chamber, FIG. 3 is a perspective view of the partition member, FIG. 4 is an exploded view of the partition member, and FIG. FIG.
[0015]
As shown in FIG. 1, one cation exchange membrane 3 and one anion exchange membrane 4 are arranged between the cathode 1 and the anode 2, and a concentration chamber / cathode chamber 5 is provided between the cathode 1 and the cation exchange membrane 3. The concentration chamber / anode chamber 6 is formed between the anode 2 and the anion exchange membrane 4, and the desalting chamber 7 is formed between the cation exchange membrane 3 and the anion exchange membrane 4. A cation exchange resin 8 is filled in each of the cathode chamber 5 and the anode chamber 6 also serving as a concentrating chamber. The ion exchange resin filled in the cathode chamber 5 and the anode chamber 6 may be an anion exchange resin or a mixture of an anion exchange resin and a cation exchange resin. From the viewpoint of the strength of the resin, a cation exchange resin is used. It is preferable to use it. The desalting chamber 7 is filled with a cation exchange resin 8 and an anion exchange resin 9 in a mixed state.
[0016]
In the electric deionization apparatus of the present invention, as another form of the concentrating chamber / cathode chamber and the concentrating chamber / anode chamber, FIG. 6 shows instead of filling both electrode chambers serving as the concentrating chamber with ion exchange resin. As described above, the cathode plate 80 and the anode plate 90 may be configured to allow electrode water to pass therethrough, and the cathode plate 80 may be in contact with the cation exchange membrane 3 and the anode plate 90 may be in contact with the anion exchange membrane 4. As a result, the electrical resistance in both the concentration chambers and electrode chambers is reduced, and it is possible to efficiently perform deionization processing even at a low applied voltage. Such electrode plates 80 and 90 are formed by stacking a plurality of perforated plates having a large number of openings penetrating in the thickness direction and partially overlapping the holes of adjacent perforated plates. Can do.
[0017]
1 to 5, raw water is introduced into the desalting chamber 7 in a state where a voltage is applied between the cathode 1 and the anode 2, and is taken out as deionized water. Cathode electrode water is circulated through the concentration chamber / cathode chamber 5, and anode electrode water is circulated through the concentration chamber / anode chamber 6. The cations in the raw water pass through the cation exchange membrane 3 and are mixed with the cathode electrode water and discharged. Anions in the raw water permeate through the anion exchange membrane 4 and enter the anode electrode water and are discharged.
[0018]
In this electric deionization apparatus, only one demineralization chamber 7, a concentration chamber / anode chamber 6 and a concentration chamber / cathode chamber 5 are arranged between the cathode 1 and the anode 2, respectively. The distance between 1 and the anode 2 is small. Therefore, even if the applied voltage between the electrodes 1 and 2 is low, a sufficient current can be passed between the electrodes 1 and 2 to perform the deionization process.
[0019]
In the present invention, Ca ²⁺ in the desalting chamber moves to the concentration chamber / cathode chamber, HCO ₃ ⁻ moves to the concentration chamber / anode chamber, and Ca ²⁺ and HCO ₃ ⁻ meet in the same concentration chamber / electrode chamber. Does not generate scale.
[0020]
In addition, since the electrode chamber also serves as the concentration chamber, the electrical conductivity of the electrode water is high. This also allows a sufficient current to flow between the electrodes 1 and 2 even if the applied voltage between the electrodes 1 and 2 is low.
[0021]
The direction of water flow in the electrode chambers / concentration chambers 5 and 6 may be demineralization chambers and parallel flow water or counter flow water, but is preferably ascending flow water. This is because gas such as H ₂ and O ₂ is generated in each of the electrode / concentration chambers 5 and 6 by a direct current, so that water flows in an upward flow to promote gas discharge and prevent drift.
[0022]
In the present invention, as the electrode water to be passed to the concentrating chamber / anode chamber and the concentrating chamber / cathode chamber, it is desirable to branch the raw water and independently pass the water to each concentrating chamber / electrode chamber. According to this water flow method, since the effluent from one electrode chamber is conventionally used as the other electrode water, the ion species that have moved from the desalting chamber to each concentration chamber / electrode chamber do not associate. , Scale is less likely to occur.
[0023]
Next, with reference to FIGS. 2-5, the electric deionization apparatus which has arrange | positioned the partition member in the demineralization chamber and formed many small chambers in the demineralization chamber is demonstrated.
[0024]
A cathode electrode plate 12 is disposed along the cathode-side end plate 11, and a frame-shaped concentrating chamber / cathode chamber forming frame frame 13 is superimposed on the peripheral edge of the cathode electrode plate 12. A cation exchange membrane 14 is superimposed on the frame-shaped frame 13, and a frame-shaped frame 20 for forming a desalting chamber, an anion exchange membrane 15, and a frame-shaped frame 17 for forming a concentration chamber are formed on the cation exchange membrane 14. They are superimposed in this order. An anode electrode plate 17 is overlaid on the anion exchange membrane 15 via a frame 16 for forming a concentration chamber / anode chamber, and an anode side end plate 18 is overlaid thereon to form a laminate. This laminate is tightened with bolts or the like.
[0025]
The inside of the frame-shaped frame 20 is a desalination chamber. A partition member 21 is provided in the desalting chamber, and the partition member 21 is filled with an ion exchange resin 23 made of a mixture of an anion exchange resin and a cation exchange resin.
[0026]
The inner space of the frame 13 for the concentration chamber / cathode chamber is the concentration chamber / cathode chamber 30, and the inner side of the frame 16 for the concentration chamber / anode chamber is the concentration chamber / anode chamber 40. The cathode chamber 30 and the anode chamber 40 also serving as a concentration chamber are filled with a cation exchange resin 8 as a conductor.
[0027]
In order to circulate the cathode electrode water through the concentration chamber / cathode chamber 30, the end plate 11 and the frame 13 are provided with through holes 31, 32, 35, and 36, respectively, and the frame 13 is provided with slits 33 and 34. .
[0028]
The through holes 31 and 32 overlap each other, and the through holes 35 and 36 also overlap each other. The through holes 32 and 35 of the frame 13 communicate with the concentration chamber / cathode chamber 30 via slits 33 and 34, respectively.
[0029]
The cathode electrode water flows in the order of the through holes 31, 32, the slit 33, the concentration chamber / cathode chamber 30, the slit 34, and the through holes 35, 36, and flows out as concentrated water / cathode electrode water.
[0030]
In order to circulate anode electrode water through the concentration chamber / anode chamber 40, through holes 41, 42, 45, 46 are provided in the end plate 18 and the frame 16, respectively, and slits 43, 44 are provided in the frame 16. .
[0031]
The through holes 41 and 42 overlap each other, and the through holes 45 and 46 also overlap each other. The through holes 42 and 45 of the frame 16 communicate with the concentration chamber / anode chamber 40 through slits 43 and 44, respectively.
[0032]
The anode electrode water flows in the order of the through holes 41 and 42, the slit 43, the concentration chamber / anode chamber 40, the slit 44, and the through holes 45 and 46, and flows out as concentrated water / anode electrode water.
[0033]
In order to circulate raw water in the desalination chamber inside the frame 20, through holes 51, 52, 53, 54, 57, 58, 59, 60 are provided in the end plate 18, the anion exchange membrane 15 and the frames 16, 20, respectively. (Reference numerals 58 and 59 are not shown), and the frame 20 is provided with slits 55 and 56. The through holes 51 and 60 are provided in the end plate 18, the through holes 54 and 57 are provided in the frame 20, the through holes 52 and 59 are provided in the frame 16, and the through holes 53 and 58 are provided in the anion exchange membrane 15. ing.
[0034]
The through holes 51 to 54 overlap each other, and the through holes 57 to 60 also overlap each other. The through holes 54 and 57 of the frame 20 communicate with the desalting chamber through slits 55 and 56, respectively.
[0035]
The raw water flows in the order of the through holes 51, 52, 53, 54, the slit 55, the desalting chamber, the slit 56, and the through holes 57 to 60, and flows out as deionized water (product water).
[0036]
The desalination chamber frame 20 is a rectangular shape that is long in the vertical direction. The partition member 21 disposed in the frame 20 has a hexagonal honeycomb shape, and a large number of small chambers 22 are disposed vertically and horizontally. A pair of sides of each small chamber 22 is arranged in the longitudinal direction of the frame 20, that is, the vertical direction.
[0037]
The partition member 21 may be integrally formed in advance, or may be a combination of a plurality of members. For example, as shown in FIG. 4, the zigzag bent plates 70 are configured by connecting the longitudinal surfaces 71 of each other. The bent plate 70 includes water-permeable oblique surfaces 72 and 73 that are continuous with the longitudinal surface 71 at an angle of 120 °. For example, an adhesive can be used to connect the longitudinal surfaces 71 to each other. The bent plate 70 is made of a material that allows water to pass therethrough but does not allow ion exchange resin to pass therethrough, such as a woven fabric, a non-woven fabric, a mesh, and a porous material. The bent plate 70 is preferably formed to have rigidity by a synthetic resin or metal having acid resistance and alkali resistance. The longitudinal surface 71 may or may not have water permeability.
[0038]
The partition member 21 may be fitted into the frame 20. Further, a water-permeable sheet or mesh may be stretched on one side of the frame 20, and a partition member may be bonded thereto.
[0039]
The raw water flowing into the desalination chamber from the through hole 54 through the through hole 55 passes through the partition member 21 surrounding the small chamber 22 as shown in FIG. 5 and flows into the adjacent small chamber 22 and gradually flows downward. Receive ion treatment. And finally, it reaches the lower part of the desalting chamber, passes through the slit 56 and the through holes 57-60, and is taken out of the electric deionization apparatus as desalted water.
[0040]
The average direction of water flow in this desalination chamber is that raw water inflow through holes 54 and slits 55 are present in the upper part of the frame 20, and desalted water extraction slits 56 and through holes 57 are in the lower part of the frame 20. From where it exists, the vertical direction is from top to bottom. Since the upper and lower portions of the small chambers are inclined with respect to the average water flow direction, the water to be treated is separated from the single small chamber 22 into the left and right small chambers 22 and flows down. For this reason, the water to be treated flows in an evenly dispersed manner in each of the small chambers 22 and the contact efficiency between the water to be treated and the ion exchange resin 23 becomes good.
[0041]
In this desalting chamber, the small chamber 22 is relatively small, and the downward pressure applied to the ion exchanger in each small chamber 22 due to its own weight and water pressure is small. Therefore, the ion exchanger is not compressed in any of the small chambers 22, and the ion exchanger is not locally consolidated in the lower part of the small chamber. In this embodiment, the ion exchange resin filled in each chamber 22 is a mixture of an anion exchange resin and a cation exchange resin, but may be any of the following (i) to (iii).
(i) Fill all the chambers with one of anion exchange resin, cation exchange resin and amphoteric ion exchange resin.
(ii) Fill all chambers with a mixture of 2 or 3 of anion exchange resin, cation exchange resin and amphoteric ion exchange resin. The mixing ratio and mixed species may all be common, or may be different in some or all of the chambers.
(iii) Filling some chambers with anion exchange resin, filling some other chambers with cation exchange resin, and filling the other chambers with a mixture of anion exchange resin and cation exchange resin or amphoteric ion exchange resin. .
[0042]
In the case of (ii) and (iii), the number of chambers filled with anion exchange resin and the number of chambers filled with cation exchange resin may be adjusted according to the anion and cation ratio of raw water.
[0043]
The LV of the demineralization chamber of this electric deionizer is preferably about 15 to 45 m / h, and the SV is preferably about 80 to 280 Hr- ¹ .
[0044]
2 to 5 also have a small number of stacked chambers between the cathode and the anode, so that the electric resistance is small and a necessary amount of current can be supplied with a small voltage.
[0045]
Further, since the honeycomb structure is filled in the desalting chamber, high-purity treated water can be obtained.
[0046]
【The invention's effect】
As described above, the electric deionization apparatus of the present invention is such that one demineralization chamber, a concentration chamber / cathode chamber, and a concentration chamber / anode chamber are arranged between the cathode and the anode, respectively, and the distance between the electrodes Since the electrode chamber and the concentrating chamber are combined and the electrode water is concentrated water with high electrical conductivity, a sufficient amount of current is passed even if the applied voltage between the electrodes is lowered, and the deionization is sufficiently performed. Can be processed. In addition, ionic species having different polarities, which are scale components, move to the respective concentration chambers / electrode chambers and do not associate with each other, so that scale hardly occurs.
[0047]
The electric deionization apparatus of the present invention is extremely suitable for applications where the amount of produced water is small, such as for small-scale laboratories and small fuel cells.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view of an electric deionization apparatus according to an embodiment.
FIG. 2 is an exploded perspective view of an electric deionization apparatus in which partition members are arranged in a demineralization chamber.
FIG. 3 is a perspective view of a partition member.
FIG. 4 is an exploded view of a partition member.
FIG. 5 is an explanatory view of water flow status of the partition member.
FIG. 6 is a schematic longitudinal sectional view of an electrical deionization apparatus according to another embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cathode 2 Anode 3 Cation exchange membrane 4 Anion exchange membrane 5 Concentration chamber / cathode chamber 6 Concentration chamber / Anode chamber 7 Desalination chamber 8 Cation exchange resin 9 Anion exchange resin 20 Frame 21 Partition member 22 Small chamber 23 Cation exchange with anion exchange resin Mixed ion exchange resin with resin 80 Cathode plate 90 Anode plate

Claims

One cation exchange membrane and one anion exchange membrane are disposed between the cathode and the anode,
A concentration chamber / cathode chamber is provided between the cathode and the cation exchange membrane,
A concentration and anode chamber is provided between the anode and the anion exchange membrane,
A desalting chamber is provided between the cation exchange membrane and the anion exchange membrane;
An electric deionization apparatus in which the cation exchange resin is filled in each of the concentration chamber / anode chamber and the concentration chamber / cathode chamber, and the ion exchanger is filled in the demineralization chamber.

One cation exchange membrane and one anion exchange membrane are disposed between the cathode plate and the anode plate,
A concentration chamber / cathode chamber is provided between the cathode plate and the cation exchange membrane,
A concentration and anode chamber is provided between the anode plate and the anion exchange membrane,
A desalting chamber is provided between the cation exchange membrane and the anion exchange membrane;
The cathode plate and the anode plate have a water passage for electrode water,
An electrical deionization apparatus, wherein the cathode plate is in contact with a cation exchange membrane, and the anode plate is in contact with the anion exchange membrane.

In claim 1 or 2,
A partition member is disposed in the desalting chamber, and a plurality of chambers surrounded by the partition member, the cation exchange membrane and the anion exchange membrane are formed in the desalting chamber,
Each of the chambers is filled with an ion exchanger,
At least a part of the partition members facing each small chamber is inclined with respect to the average water flow direction in the desalination chamber,
An electric deionization apparatus characterized in that at least the inclined portion of the partition member has a structure that allows water to pass but prevents passage of an ion exchanger.

The electric deionization apparatus according to any one of claims 1 to 3 , wherein a branch flow of the raw water is branched from the raw water flow channel flowing into the desalination chamber, and a part of the raw water is concentrated through the branch flow channel. electrodeionization apparatus characterized by being configured to be passed through independently into chamber and the anode chamber and the concentrating compartment and the cathode compartment.