JP3729348B2

JP3729348B2 - Electric regenerative desalination equipment

Info

Publication number: JP3729348B2
Application number: JP2002136604A
Authority: JP
Inventors: 修行井上; 淳青山
Original assignee: Ebara Corp
Current assignee: Ebara Corp
Priority date: 2002-05-13
Filing date: 2002-05-13
Publication date: 2005-12-21
Anticipated expiration: 2022-05-13
Also published as: JP2003326271A

Description

【０００１】
【発明の属する技術分野】
本発明は、電気再生式脱塩装置に係り、特に、１台の電気再生式脱塩装置で、外部に異なった２種類の純度の純水を供給することができる電気再生式脱塩装置に関する。
【０００２】
【従来の技術】
従来の純水製造方法としては、イオン交換樹脂を充填した容器に脱塩室入口水を通過させ、脱塩室入口水中のイオンをＨ⁺、ＯＨ^-イオンに、交換することにより純水を製造するイオン交換法が知られている。
しかし、このイオン交換法では、イオン交換樹脂の交換能力が飽和すると、イオン交換樹脂の種類に応じて酸、アルカリを用いてイオン交換能力の再生をする必要がある。イオン交換樹脂の再生操作は、煩雑で、多量の酸、アルカりの貯蔵、取り扱い及び廃棄に細心の注意が必要であると共に設備が大きくなる、という問題を有している。
それに対し、近年、電気によってイオン交換体を再生し、連続的に純水を製造する電気再生式脱塩装置が開発された。これは、図３に示すように、脱塩室入口水１０中のイオン分を装置の両端に印可した直流電源により、濃縮室出口水１３及び陰極室出口水１５、陽極室出口水１７に移動させることにより除去する装置であり、陰極１を有する陰極室２と陽極３を有する陽極室４、陰極室２と陽極室４の間に陰イオン交換膜５と陽イオン交換膜６を配置することにより形成された脱塩室７と濃縮室８を備え、少なくとも脱塩室７内にはイオン交換体９が充填されているものである。
【０００３】
ここで、イオン交換体９は、イオン交換樹脂、イオン交換繊維、グラフト重合法によりイオン交換基を導入されたイオン交換不織布、スペーサ等のイオン交換機能を持つ物であればどのようなイオン交換体でもよく、陰イオン交換体、陽イオン交換体を単一、もしくは混合、もしくは複層状に充填してある。
陰極室２に陰極室入口水１４を、陽極室４に陽極室入口水１６を、濃縮室８に濃縮室入口水１２を、脱塩室７に脱塩室入口水１０を導入し、陰極１と陽極３間に直流電流を印可することにより、脱塩室入口水１０中に含まれているイオン分は、イオン交換体９の表面を電位の方向に移動し、陰イオンは陰イオン交換膜５、陽イオンは陽イオン交換膜６を透過して、濃縮室８中の濃縮水、陰極室２中の陰極液及び陽極室４中の陽極液に移動し、脱塩室入口水１０は脱イオン処理され純水１１が製造される。
【０００４】
脱塩室７内に充填されたイオン交換体９は、水解によって発生するＨ⁺、ＯＨ^-により連続的に再生されるため、酸あるいはアルカリによる再生作業は必要なく、このようにして純水１１を連続的に製造することが可能となる（特許第１７８２９４３、特許第２７５１０９０、特許第２６９９２５６号各明細書、特願平１０−１５３６９７号）。
また、最近では、脱塩室７を中間イオン交換膜で２つの脱塩室に分割し、片方の脱塩室の流出水をもう片方の脱塩室に導入することで、脱塩性能を改善した電気再生式脱塩装置も開発されている（特開２００１−２３９２７０、特開２００１−３２７９７１号各公報）。
【０００５】
前記従来の電気再生式脱塩装置では、炭酸、シリカなどの弱陰イオン成分の除去能力が、他のイオン分の除去能力に比べて劣っていることが一般に知られている。
これらの弱陰イオン成分は、電気再生式脱塩装置に直流電流を過大に印可すれば、その除去率が多少改善することも知られているが、その場合でも、弱陰イオン成分は十分には除去できなく、単位流量当りの消費電力は大きくなってしまう。
そのため、残存弱陰イオン成分の除去には、必要に応じてカートリッジポリッシャーや電気再生式脱塩装置を後段に設置する必要があり、設置面積、機器数の増加、価格の上昇を招くことになる。
また、純水の使用箇所によっては、比抵抗の高い純水と、比抵抗の比較的低い純水の２種類の純水を使用することがあり、そのような場合は、比抵抗の高い純水に、炭酸ガス等を添加することにより比抵抗を下げる操作を行うこともある。しかし、このような処置を行うことは、一度高度に脱塩した純水に不純物を添加するため、炭酸ガス等の添加装置やその制御などが必要になり、設置面積、機器数の増加、価格の上昇を招くことになる。
【０００６】
【発明が解決しようとする課題】
本発明は、上記従来技術の問題点を解消し、電気再生式脱塩装置の弱陰イオン成分の除去性能を高めると共に、外部に２種以上の水質の異なる純水を供給することができる電気再生式脱塩装置を提供することを課題とする。
【０００７】
【課題を解決するための手段】
上記課題を解決するために、本発明では、陰極を有する陰極室と、陽極を有する陽極室とを有し、該両極室間に、陽極側に陽イオン交換膜、陰極側に陰イオン交換膜を配置して構成される濃縮室と、次の（ａ）〜（ｅ）の脱塩室、（ａ）陰極側に陽イオン交換膜陽極側に陰イオン交換膜を配置し、内部にイオン交換体を充填した脱塩室、（ｂ）両側に陽イオン交換膜を配置し、内部にイオン交換体を充填した脱塩室、（ｃ）両側に陰イオン交換膜を配置し、内部にイオン交換体を充填した脱塩室、（ｄ）陰極側に陽イオン交換膜、陽極側にバイポーラ膜を配置し、内部にイオン交換体を充填した脱塩室、（ｅ）陰極側にバイポーラ膜、陽極側に陰イオン交換膜を配置し、内部にイオン交換体を充填した脱塩室、のいずれか１種類以上の脱塩室とを配置して構成される電気再生式脱塩装置であって、前記脱塩室として、両側に濃縮室を配置した前記いずれかの脱塩室と、間に濃縮室を介さずに前記いずれか１種類以上の脱塩室を複数隣接して配置した脱塩室群とを、それぞれ１以上有することとしたものである。
【０００８】
前記電気再生式脱塩装置において、濃縮室を介さずに配置した脱塩室群は、前記脱塩室群を構成する第１の脱塩室に導入された被処理水が、第１の脱塩室から前記脱塩室群を構成する最終の脱塩室まで、順次直列で通水して脱塩処理されるように接続するのがよく、前記（ａ）の脱塩室に充填されるイオン交換体は、陰イオン交換体、陽イオン交換体、又は陰イオン交換体と陽イオン交換体の両方のイオン交換体であり、前記（ｂ）の脱塩室に充填されるイオン交換体は、陽イオン交換体であり、前記（ｃ）の脱塩室に充填されるイオン交換体は、陰イオン交換体であり、前記（ｄ）の脱塩室に充填されるイオン交換体は、陽イオン交換体であり、前記（ｅ）の脱塩室に充填されるイオン交換体は陰イオン交換体であるのがよく、また、前記イオン交換体は、放射線グラフト重合法によりイオン交換基が導入されたイオン交換繊維からなるイオン交換体であり、イオン交換繊維からなるイオン交換体は、不織布又は織布、及び網目状のスペーサとすることができる。
【０００９】
【発明の実施の形態】
本発明によれば、両側に濃縮室が隣接する通常の脱塩室と、間に濃縮室を介さずに複数の脱塩室を配置した弱陰イオン分の除去性能が高い脱塩室群とを用いて、１台の電気再生式脱塩装置を構成することで、弱陰イオン分の除去性能を高めた比抵抗の高い純水を得ることができると共に、従来の電気再生式脱塩装置で得られる程度の純水をも同時に得られるため、２種類の水質の純水を外部に供給することができる。
【００１０】
次に、図面を用いて本発明を詳細に説明する。
図１は、本発明による電気再生式脱塩装置の一例を示す概略構成図であり、図１では、前記した図３に示す構成と同一構成を同一符号で示して説明する。
陰極１を有する陰極室２と、陽極３を有する陽極室４を対向して配置し、この陰極室２と陽極室４の間に、陰極１側に陰イオン交換膜５を、陽極３側に陽イオン交換膜６を配置して構成された濃縮室８と、陰極１側に陽イオン交換膜６を、陽極３側に陰イオン交換膜５を配置して構成された脱塩室７と、両側に陰イオン交換膜５を配置して構成された脱塩室７１、７２と、陰極１側に陽イオン交換膜６を、陽極３側に陰イオン交換膜５を配置して構成された脱塩室７３とから、間に濃縮室を介さずに構成した脱塩室群７０とにより、本発明による電気再生式脱塩装置が構成される。
【００１１】
ここで脱塩室群は、第１の脱塩室７１の出口が第２の脱塩室７２の入口に、第２の脱塩室７２の出口が第３の脱塩室７３の入口に接続されており、第１の脱塩室７１、第２の脱塩室７２の両側に存在するイオン交換膜は陰イオン父換膜５であるため、内部に充填するイオン交換体９は陰イオン交換体とし、第３の脱塩室７３、及び脱塩室７は陰イオン交換膜５と陽イオン交換膜６で形成されているため、充填するイオン交換体９は、陰イオン交換体と陽イオン交換体の混合イオン交換体とした。
これは、脱塩室の両側にあるイオン交換膜が陰イオン交換膜５と陽イオン交換膜６である場合には、電極間に直流電流を印可すると、被処理水中の陰イオンは陰イオン交換膜５を通過して濃縮室８へ、陽イオンは陽イオン交換膜６を通過して濃縮室８へ移動するため、陰イオン交換体と陽イオン交換体の両方を脱塩室に充填すると脱イオン効果があるのに対し、脱塩室の両側にあるイオン交換膜が両方とも陰イオン交換膜５の場合は、被処理水中の陽イオンは陰イオン交換膜５を通過できないため、陽イオン交換体を内部に充填していても連続脱塩効果が期待できないためである。
【００１２】
同様に、両側に陽イオン交換膜６を配置した脱塩室を用いる場合には、陰イオンは陽イオン交換膜６を通過できないため、内部には陽イオン交換体のみを充填するのがよい。
また、濃縮室８、及び両極室２、４にも、イオン交換体９を充填することが望ましく、このイオン交換体９は、その形状、種類に特に制限はないが、濃縮室８には陽イオン交換体と陰イオン交換体の両者を使用し、陽イオン交換膜側に陽イオン交換体を、陰イオン交換膜側に陰イオン交換体を配置するのが析出の防止に効果的である。
陰極室２には、脱塩室７が隣接する場合には陽イオン交換体を、濃縮室８が隣接する場合には陰イオン交換体を充填するのがよく、陽極室４には、脱塩室７が隣接する場合には陰イオン交換体を、濃縮室８が隣接する場合には陽イオン交換体を充填するのがよい。
濃縮室８、両極室２、４には、一部にイオン交換体以外の、例えばスペーサを充填することもできる。
【００１３】
陰極室２に陰極室入口水１４を、陽極室４に陽極室入口水１６を、濃縮室８に濃縮室入口水１２を、脱塩室７に脱塩室入口水１０を、脱塩室群７０のうちの第１の脱塩室７１に脱塩室群入口水１８を導入し、陰極１と陽極３間に直流電流を印可することにより、脱塩室入口水１０及び脱塩室群入口水１８中に含まれているイオン分は、イ才ン交換体９の表面を電位の方向に移動し、陰イオンは陰イオン交換膜５、陽イオンは陽イオン交換膜６を透過して、濃縮室８中の濃縮水、陰極室２中の陰極水、陽極室４中の陽極水に移動し系外に排出され、脱塩室入口水１０及び脱塩室群入口水１８は脱イオン処理され、脱塩室出口純水１１及び脱塩室群出口純水１９が製造される。
１以上の脱塩室７と１以上の脱塩室群７０は、各々同じ脱塩室入口水１０を処理しても、別の水を処理してもかまわず、脱塩室７と脱塩室群７０の出口水は、別々に外部に供給してもかまわず、混合して供給してもよい。
また、脱塩室７の出口水を脱塩室群７０を構成している第１の脱塩室７１に導入してさらに脱塩処理しても、脱塩室群７０を構成している最終の脱塩室７３の出口水を脱塩室７の入口水として用いることも可能である。
【００１４】
脱塩室７の出口水１１を脱塩室群７０に導入する場合、及び脱塩室群７０の出口水１９を脱塩室７に導入する場合はさらに高度の脱塩効果が期待できる。
脱塩室群７０の作用について詳しく説明すると、第１の脱塩室７１に導入された脱塩室入口水１０中の陰イオン分は、両極に印可された直流電流により陽極３側に移動し、陰イオン交換膜５を透過して濃縮室８中に移動する。陽イオン分は、陰極側に配置されている陰イオン交換膜５を透過することができないため、第１の脱塩室７１に留まる。これにより、第１の脱塩室７１内は陰イオン分のみが減少するためｐＨが高くなり、弱アニオン成分もイオン化することで除去しやすくなる。陰極側に配置されているイオン交換膜５からは、第２の脱塩室７２で除去される残存陰イオン分とＯＨ^-が第１の脱塩室７１に透過してくる。このＯＨ^-の作用で、第１の脱塩室７１内に充填されている陰イオン交換体は再生され、再び脱塩室入口水１０中の陰イオン分を除去できるようになる。
【００１５】
第１の脱塩室７１で上述の脱塩処理をされた処理水は、続いて第２の脱塩室７２に導入される。ここでも第１の脱塩室７１での脱塩処理と同様に、陰イオン分は陰イオン交換膜５を透過して第１の脱塩室へ移動し、陽イオン分は処理水中に留まるため、処理水は第２の脱塩室７２に導入された時点からｐＨが高いまま保持され、さらに弱陰イオン成分の脱塩効果を高くしている。これにより、第１の脱塩室７１で脱塩しきれなかった、主に弱陰イオン分かなる残存陰イオン分が除去される。
陰極１側に存在する陰イオン交換膜５からは、主にＯＨ^-が第２の脱塩室７２に透過してくるため、第２の脱塩室中の陰イオン交換体は、第１の脱塩室７１中の陰イオン交換体よりも効率よく再生され、第１の脱塩室で除去しきれなかった陰イオン成分の除去を効率よく行うことができる。
第２の脱塩室７２でさらに脱塩処理された処理水は、第３の脱塩室７３に導入され、最終的な脱塩処理が行われる。
【００１６】
第３の脱塩室７３に導入された時点で、処理水中の陰イオン成分はほとんどなくなっており、極微量の弱陰イオン成分及び陽イオン成分が除去の対象となる。第３の脱塩室７３には、陽イオン交換体と陰イオン交換体が充填されており、陽イオン分は陽イオン交換体とイオン交換された後、陰極１側に存在する陽イオン交換膜６を透過して濃縮室８に移動する。残存する微量の弱陰イオン成分は、第３の脱塩室７３中の陰イオン交換体とイオン交換した後、陽極３側にある陰イオン交換膜５を透過して、第２の脱塩室７２に移動する。
第３の脱塩室では、イオン分の移動の他、水解によって水がＨ⁺とＯＨ^-に分解されており、これが第３の脱塩室７３中の陽イオン交換体、陰イオン交換体を再生すると共に、ＯＨ^-は、第１、第２の脱塩室７１、７２内に充填された陰イオン交換体の再生にも用いられるため、酸、アルカリによるイオン交換体の再生作業は必要なく、このようにして、脱塩室入口水１０中のイオン分は、弱陰イオン成分も含めて十分に除去され、連続的に純水１９を得ることができる。
【００１７】
ここで、陽イオン分は、弱陰イオン分に比べ遥かに除去し易いため、通常は第３の脱塩室７３だけで十分除去することが可能だが、脱塩室入口水１０中に陽イオン成分が多量に含まれている場合には、本図であげている第３の脱塩室に充填するイオン交換体を陽イオンのみとすることで、陽イオンの除去能力を増大したり、第２の脱塩室７２の陽極側のイオン交換膜を陽イオン交換膜６に変更し、第２の脱塩室７２に充填されているイオン交換体を陽イオン交換体と陰イオン交換体の混合イオン交換体とすると共に、第３の脱塩室７３中のイオン交換体を陽イオン交換体とし、第１の脱塩室７１から流出した処理水を第３の脱塩室７３に導入し、さらに陰イオン交換体と陽イオン交換体の充填された第２の脱塩室７２に導入する、という処理方法を行って陽イオンの除去能力を増大させてもよい。
また、本図の第３の脱塩室７３に加え、さらに第４の脱塩室を設け、第３の脱塩室７３の出口水をさらに脱塩処理するということも可能である。
【００１８】
脱塩室群７０を、片側にバイポーラ膜を配置した脱塩室を使用して構成する場合は、陰イオン交換膜とバイポーラ膜で形成された脱塩室内部には陰イオン交換体を、バイポーラ膜と陽イオン交換膜で形成された脱塩室内部には陽イオン交換体を充填すると脱塩効率が高い。
バイポーラ膜の特性から、バイポーラ膜にて低電圧で効率的に水解によるＨ⁺、ＯＨ^-が発生し、Ｈ⁺は陽イオン交換体を、ＯＨ^-は陰イオン交換体を再生させ、脱塩室群入口水１８中のイオン分を除去することが可能となる。
水解を効率的に発生させられるため、バイポーラ膜を用いた場合は、さらに運転電圧が低減することが期待できる。
また、電気再生式脱塩装置においては、従来、脱塩室の数の±１の濃縮室が必要であったのが、上述のように、複数枚のイオン交換膜で分割された脱塩室を用いて電気再生式脱塩装置を形成することにより、濃縮室の室数を減らすことが可能になり、その分運転電圧を軽減することも可能となる。
【００１９】
【実施例】
以下、本発明を実施例により具体的に説明する。
実施例１
この実施例では、本発明の効果を比較例との対比の元で説明する。試験設備は、図２に示す試験装置のフロー図の通りであり、、脱塩室入口水１０、濃縮室入口水１、陰極室入口水１４、陽極室入口水１６として、藤沢市水を活性炭濾過器、保安フィルタ、逆浸透膜装置で前処理したものを使用し、その水質は、比抵抗０．２５ＭΩ・ｃｍであった。
本実施例では、図２に示す試験装置中の電気再生式脱塩装置に、図１に示す構成の電気再生式脱塩装置を用い、脱塩室入口水１０の流量を１００Ｌ／ｈ、脱塩室群入口水１８の流量を１５０Ｌ／ｈ、濃縮室入口水１２の流量を５０Ｌ／ｈ、陰極室入口水１４の流量及び陽極室入口水１６の流量をそれぞれ１０Ｌ／ｈとして、０．４Ａの直流電流を陰極１と陽極３に印可して運転を行った。
【００２０】
電気再生式脱塩装置は、電極面積６４０ｃｍ²、脱塩室は１０室でそのうちの６室を２つの脱塩室群７０に用い、脱塩室群７０のうち、第１の脱塩室７１、第２の脱塩室７２は、両側を陰イオン交換膜５で形成し、内部に陰イオン交換体を、第３の脱塩室７３及び脱塩室７は、陰イオン交換膜５と陽イオン交換膜６で形成し、陰イオン交換体と陽イオン交換体を充填した構成とした。
濃縮室８は５室とし、両端に陰極室２と陽極室４を設けた。
また、濃縮室８の内部には、陰イオン交換体と陽イオン交換体を、陰極室２の内部には、陽イオン交換体と導電性をもたないスペーサを、陽極室４の内部には、陰イオン交換体と導電性を持たないスペーサを充填した。
上記条件で運転した結果、脱塩室群７０からは比抵抗１７．７ＭΩ・ｃｍ、炭酸、シリカの除去率が共に９９％程度の脱塩室群出口純水１９が、脱塩室７からは比抵抗１４．２ＭΩ・ｃｍ、炭酸除去率９４％、シリカ除去率８８％程度の脱塩室出口純水１１が連続して得られた。
【００２１】
比抵抗が高い純水と、それほど高くなくてもかまわない純水の２種類を使用するような場合は、本発明においては、複数の脱塩室を濃縮室を介さないで形成した脱塩室群７０と、両側に濃縮室８を配置した脱塩室７の各部屋数、通水流量を変化させることで、１台の電気再生式脱塩装置で、２種類の目的にあった比抵抗の純水を得ることが可能となる。
濃縮室８の部屋数が、下記の比較例１の９室に対して５室に減少しているため、運転電圧は１８０V程度と比較例１に比べ低かった。
また、脱塩室出口純水１１と脱塩室群出口純水１９の両者を混合して用いる場合にも、混合された純水の水質は、１６．０ＭΩ・ｃｍで、炭酸除去率は約９７％、シリカ除去率は約９５％と比較例１に対して高い比抵抗の純水が得られた。
【００２２】
比較例１
比較例として、図３に示す構成の電気再生式脱塩装置を用い、脱塩室入口水１０の流量を２５０Ｌ／ｈ、濃縮室入口水１２の流量を９０Ｌ／ｈ、陰極室入口水１４の流量及び陽極室入口水１６の流量をそれぞれ１０Ｌ／ｈとして、０．４Ａの直流電流を陰極１と陽極３に印可して運転を行った。
電気再生式脱塩装置は、電極面積６４０ｃｍ²、脱塩室は１０室、濃縮室は９室とし、両端に陰極室と陽極室を設け、脱塩室、濃縮室内部には陰イオン交換体と陽イオン交換体を、陰極室には陽イオン交換体を、陽極室には陰イオン交換体を充填してある。
上記条件で運転した結果、比抵抗１４．４ＭΩ・ｃｍ程度の純水１１が連続して製造された。
この運転において、運転電圧は２１０Ｖ、炭酸除去率９５％、シリカ除去率８８％であった。
【００２３】
【発明の効果】
本発明の電気再生式脱塩装置によれば、上述したように、被処理水中の弱陰イオン成分を除去する能力を高め比抵抗の高い純水を得ることができると共に、水質の異なる２種類の純水を外部に供給することが可能となる。
【図面の簡単な説明】
【図１】本発明の電気再生式脱塩装置の一例を示す概略構成図。
【図２】実施例に用いた試験装置のフロー図。
【図３】従来の電気再生式脱塩装置の一例を示す概略構成図。
【符号の説明】
１：陰極、２：陰極室、３：陽極、４：陽極室、５：陰イオン交換膜、６：陽イオン交換膜、７：脱塩室、８：濃縮室、９：イオン交換体、１０：脱塩室入口水、１１：純水、１２：濃縮室入口水、１３：濃縮室出口水、１４：陰極室入口水、１５：陰極室出口水、１６：陽極室入口水、１７：陽極室出口水、１８：脱塩室群入口水、１９：純水、７１：脱塩室群を構成する第１の脱塩室、７２：脱塩室群を構成する第２の脱塩室、７３：脱塩室群を構成する第３の脱塩室[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric regeneration type desalination apparatus, and more particularly, to an electric regeneration type desalination apparatus that can supply two different types of pure water to the outside with one electric regeneration type desalination apparatus. .
[0002]
[Prior art]
As a conventional method for producing pure water, pure water is produced by passing deionization chamber inlet water through a container filled with ion exchange resin and exchanging ions in the demineralization chamber inlet water for H ⁺ and OH ⁻ ions. An ion exchange method is known.
However, in this ion exchange method, when the exchange capacity of the ion exchange resin is saturated, it is necessary to regenerate the ion exchange capacity using an acid or an alkali according to the type of the ion exchange resin. The regeneration operation of the ion exchange resin is complicated and has a problem that a large amount of acid and alkali must be stored, handled and disposed of with great care and the equipment becomes large.
On the other hand, in recent years, an electric regenerative desalination apparatus that regenerates ion exchangers by electricity and continuously produces pure water has been developed. As shown in FIG. 3, this is transferred to the concentrating chamber outlet water 13, the cathode chamber outlet water 15, and the anode chamber outlet water 17 by a DC power source in which ions in the desalting chamber inlet water 10 are applied to both ends of the apparatus. The anion exchange membrane 5 and the cation exchange membrane 6 are arranged between the cathode chamber 2 having the cathode 1 and the anode chamber 4 having the anode 3, and between the cathode chamber 2 and the anode chamber 4. The desalting chamber 7 and the concentration chamber 8 formed by the above are provided, and at least the desalting chamber 7 is filled with an ion exchanger 9.
[0003]
Here, the ion exchanger 9 is any ion exchanger as long as it has an ion exchange function, such as an ion exchange resin, an ion exchange fiber, an ion exchange nonwoven fabric into which an ion exchange group is introduced by a graft polymerization method, and a spacer. Alternatively, the anion exchanger and the cation exchanger are filled in a single layer, a mixture, or a multilayer.
The cathode chamber inlet water 14 is introduced into the cathode chamber 2, the anode chamber inlet water 16 is introduced into the anode chamber 4, the concentration chamber inlet water 12 is introduced into the concentration chamber 8, and the desalination chamber inlet water 10 is introduced into the desalting chamber 7. By applying a direct current between the anode 3 and the anode 3, ions contained in the desalting chamber inlet water 10 move on the surface of the ion exchanger 9 in the direction of the potential, and the anions are converted into anion exchange membranes. 5. The cation passes through the cation exchange membrane 6 and moves to the concentrated water in the concentration chamber 8, the catholyte in the cathode chamber 2, and the anolyte in the anode chamber 4. The pure water 11 is manufactured by ion treatment.
[0004]
Since the ion exchanger 9 filled in the desalting chamber 7 is continuously regenerated by H ⁺ and OH ⁻ generated by hydrolysis, there is no need to regenerate with acid or alkali. Can be produced continuously (Japanese Patent No. 1784243, Japanese Patent No. 2751090, Japanese Patent No. 2699256, Japanese Patent Application No. 10-153697).
Recently, the desalination performance has been improved by dividing the desalination chamber 7 into two desalination chambers with an intermediate ion exchange membrane and introducing the effluent water from one desalination chamber into the other desalination chamber. An electric regeneration type desalination apparatus has also been developed (Japanese Patent Laid-Open Nos. 2001-239270 and 2001-327971).
[0005]
In the conventional electric regeneration type desalination apparatus, it is generally known that the ability to remove weak anion components such as carbonic acid and silica is inferior to the ability to remove other ions.
These weak anion components are known to have a somewhat improved removal rate if a DC current is excessively applied to an electric regeneration type desalination apparatus. Cannot be removed, and power consumption per unit flow rate becomes large.
For this reason, it is necessary to install a cartridge polisher and an electric regenerative desalting apparatus in the subsequent stage as necessary to remove the remaining weak anion component, which leads to an increase in the installation area, the number of devices, and an increase in price. .
Depending on the location of pure water, two types of pure water with high specific resistance and pure water with relatively low specific resistance may be used. In such a case, pure water with high specific resistance is used. An operation of lowering the specific resistance may be performed by adding carbon dioxide gas or the like to water. However, this kind of treatment adds impurities to pure water that has been once highly desalted, so an addition device such as carbon dioxide gas and its control are required, which increases the installation area, the number of devices, and the price. Will lead to an increase.
[0006]
[Problems to be solved by the invention]
The present invention solves the above-mentioned problems of the prior art, improves the performance of removing weak anion components of the electric regeneration type desalination apparatus, and can supply two or more kinds of pure water having different water quality to the outside. It is an object of the present invention to provide a regenerative desalination apparatus.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has a cathode chamber having a cathode and an anode chamber having an anode, and a cation exchange membrane on the anode side and an anion exchange membrane on the cathode side between the two electrode chambers. (A) Deionization chambers (a) to (e) below: (a) Cation exchange membrane on the cathode side, anion exchange membrane on the anode side, and ion exchange inside A desalting chamber filled with body, (b) a cation exchange membrane placed on both sides, and a desalting chamber filled with ion exchanger inside, (c) an anion exchange membrane placed on both sides, and ion exchange inside A desalting chamber filled with a body, (d) a cation exchange membrane on the cathode side, a bipolar membrane on the anode side, and a desalting chamber filled with an ion exchanger inside, (e) a bipolar membrane on the cathode side, an anode One or more types of demineralization chambers, in which an anion exchange membrane is arranged on the side and an ion exchanger is filled inside An electric regenerative desalination apparatus configured by arranging any one of the desalting chambers having a concentrating chamber on both sides as the desalting chamber, and without any concentrating chamber therebetween Each has at least one demineralization chamber group in which a plurality of one or more types of demineralization chambers are arranged adjacent to each other.
[0008]
In the electric regenerative desalination apparatus, the desalting chamber group disposed without the concentration chamber has the treated water introduced into the first desalting chamber constituting the desalting chamber group as the first desalting chamber. From the salt chamber to the final desalting chamber constituting the desalting chamber group, it is preferable to connect them so that they are successively desalted by passing water in series, and the desalting chamber of (a) is filled. The ion exchanger is an anion exchanger, a cation exchanger, or an ion exchanger of both an anion exchanger and a cation exchanger, and the ion exchanger filled in the desalting chamber of (b) is The ion exchanger filled in the desalting chamber of (c) is an anion exchanger, and the ion exchanger charged in the desalting chamber of (d) is a cation exchanger. The ion exchanger which is an ion exchanger and is filled in the desalting chamber of (e) may be an anion exchanger, and The on-exchanger is an ion exchanger composed of ion-exchange fibers into which ion-exchange groups have been introduced by a radiation graft polymerization method, and the ion-exchanger composed of ion-exchange fibers is a non-woven fabric or a woven fabric, and a network spacer be able to.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
According to the present invention, a normal desalting chamber having concentrating chambers adjacent on both sides, and a desalting chamber group having a high ability to remove weak anions, in which a plurality of desalting chambers are arranged without interposing a concentrating chamber, By using this, it is possible to obtain pure water with high specific resistance with improved weak anion content removal performance by configuring one electric regenerative demineralizer, and a conventional electric regenerative demineralizer Since the pure water of the grade obtained by this can be obtained at the same time, two types of pure water can be supplied to the outside.
[0010]
Next, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an example of an electric regeneration type desalination apparatus according to the present invention. In FIG. 1, the same configuration as that shown in FIG.
A cathode chamber 2 having a cathode 1 and an anode chamber 4 having an anode 3 are arranged to face each other, and an anion exchange membrane 5 is disposed on the cathode 1 side between the cathode chamber 2 and the anode chamber 4 and on the anode 3 side. A concentration chamber 8 configured by disposing a cation exchange membrane 6; a desalting chamber 7 configured by disposing a cation exchange membrane 6 on the cathode 1 side and an anion exchange membrane 5 on the anode 3 side; Desalting chambers 71 and 72 configured by disposing the anion exchange membrane 5 on both sides, a deionization structure configured by disposing the cation exchange membrane 6 on the cathode 1 side and the anion exchange membrane 5 on the anode 3 side. An electric regenerative desalination apparatus according to the present invention is constituted by the salt chamber 73 and the desalination chamber group 70 configured without a concentrating chamber therebetween.
[0011]
Here, in the desalting chamber group, the outlet of the first desalting chamber 71 is connected to the inlet of the second desalting chamber 72, and the outlet of the second desalting chamber 72 is connected to the inlet of the third desalting chamber 73. Since the ion exchange membranes present on both sides of the first desalting chamber 71 and the second desalting chamber 72 are the anion substitution membranes 5, the ion exchanger 9 filled inside is anion exchange. Since the third desalting chamber 73 and the desalting chamber 7 are formed of the anion exchange membrane 5 and the cation exchange membrane 6, the ion exchanger 9 to be filled is composed of the anion exchanger and the cation. A mixed ion exchanger of the exchanger was used.
This is because, when the ion exchange membranes on both sides of the desalting chamber are the anion exchange membrane 5 and the cation exchange membrane 6, when a direct current is applied between the electrodes, the anions in the water to be treated are anion exchanged. Since the cation moves through the membrane 5 to the concentrating chamber 8 and the cation passes through the cation exchange membrane 6 to the concentrating chamber 8, it is removed when both the anion exchanger and the cation exchanger are filled in the desalting chamber. In the case where both of the ion exchange membranes on both sides of the desalting chamber are anion exchange membranes 5 while having an ionic effect, the cations in the water to be treated cannot pass through the anion exchange membrane 5, so that cation exchange is performed. This is because a continuous desalting effect cannot be expected even if the body is filled inside.
[0012]
Similarly, in the case of using a desalination chamber in which cation exchange membranes 6 are arranged on both sides, anions cannot pass through the cation exchange membrane 6, and therefore it is preferable to fill only the cation exchanger inside.
Further, it is desirable that the concentration chamber 8 and the bipolar chambers 2 and 4 are also filled with the ion exchanger 9, and the shape and type of the ion exchanger 9 are not particularly limited. Using both an ion exchanger and an anion exchanger, placing a cation exchanger on the cation exchange membrane side and an anion exchanger on the anion exchange membrane side is effective in preventing precipitation.
The cathode chamber 2 may be filled with a cation exchanger when the desalting chamber 7 is adjacent, and an anion exchanger when the concentrating chamber 8 is adjacent. When the chamber 7 is adjacent, an anion exchanger may be filled, and when the concentration chamber 8 is adjacent, a cation exchanger may be filled.
The concentration chamber 8 and the bipolar chambers 2 and 4 can be partially filled with, for example, a spacer other than the ion exchanger.
[0013]
The cathode chamber inlet water 14 for the cathode chamber 2, the anode chamber inlet water 16 for the anode chamber 4, the concentration chamber inlet water 12 for the concentration chamber 8, the desalination chamber inlet water 10 for the desalination chamber 7, and the desalination chamber group. The desalination chamber group inlet water 18 is introduced into the first demineralization chamber 71 of 70, and a direct current is applied between the cathode 1 and the anode 3. The ions contained in the water 18 move on the surface of the ion exchanger 9 in the direction of the electric potential, the anions permeate the anion exchange membrane 5 and the cations permeate the cation exchange membrane 6, The concentrated water in the concentration chamber 8, the cathode water in the cathode chamber 2, and the anode water in the anode chamber 4 are moved to the outside of the system and discharged, and the desalting chamber inlet water 10 and the desalting chamber group inlet water 18 are deionized. Thus, the desalting chamber outlet pure water 11 and the desalting chamber group outlet pure water 19 are produced.
The one or more desalting chambers 7 and the one or more desalting chamber groups 70 may treat the same desalting chamber inlet water 10 or different water, respectively. The outlet water of the chamber group 70 may be supplied to the outside separately, or may be supplied after mixing.
Further, even when the outlet water of the desalting chamber 7 is introduced into the first desalting chamber 71 constituting the desalting chamber group 70 and further desalted, the final desalination chamber 70 is formed. It is also possible to use the outlet water of the desalting chamber 73 as the inlet water of the desalting chamber 7.
[0014]
When the outlet water 11 of the desalting chamber 7 is introduced into the desalting chamber group 70 and when the outlet water 19 of the desalting chamber group 70 is introduced into the desalting chamber 7, a higher degree of desalting effect can be expected.
The action of the desalting chamber group 70 will be described in detail. The anion content in the desalting chamber inlet water 10 introduced into the first desalting chamber 71 is moved to the anode 3 side by the direct current applied to both electrodes. Then, it passes through the anion exchange membrane 5 and moves into the concentration chamber 8. Since the cation content cannot pass through the anion exchange membrane 5 disposed on the cathode side, it remains in the first desalting chamber 71. Thereby, since only the anion content decreases in the first desalting chamber 71, the pH becomes high, and the weak anion component is easily removed by ionization. From the ion exchange membrane 5 arranged on the cathode side, the remaining anions and OH ⁻ removed in the second desalting chamber 72 are transmitted to the first desalting chamber 71. By the action of OH ⁻ , the anion exchanger filled in the first desalting chamber 71 is regenerated, and the anion content in the desalting chamber inlet water 10 can be removed again.
[0015]
The treated water that has been subjected to the desalting treatment in the first desalting chamber 71 is then introduced into the second desalting chamber 72. Here too, as in the desalting process in the first desalting chamber 71, the anion component passes through the anion exchange membrane 5 and moves to the first desalting chamber, and the cation component remains in the treated water. The treated water is maintained at a high pH from the time when it is introduced into the second desalting chamber 72, and the desalting effect of the weak anion component is further enhanced. As a result, residual anions, which are mainly weak anions, that could not be desalted in the first desalting chamber 71 are removed.
From the anion exchange membrane 5 present on the cathode 1 side, mainly OH ⁻ permeates into the second demineralization chamber 72, so that the anion exchanger in the second demineralization chamber is the first deionization chamber. The anion components that are regenerated more efficiently than the anion exchanger in the desalting chamber 71 and could not be removed in the first desalting chamber can be efficiently removed.
The treated water further desalted in the second desalting chamber 72 is introduced into the third desalting chamber 73, and a final desalting treatment is performed.
[0016]
When introduced into the third desalting chamber 73, the anion component in the treated water is almost gone, and a very small amount of weak anion component and cation component are to be removed. The third desalting chamber 73 is filled with a cation exchanger and an anion exchanger, and the cation is ion-exchanged with the cation exchanger and then present on the cathode 1 side. 6 passes through to the concentration chamber 8. The remaining trace amount of weak anion component is ion-exchanged with the anion exchanger in the third desalting chamber 73 and then permeates through the anion exchange membrane 5 on the anode 3 side so as to pass through the second desalting chamber. Move to 72.
In the third demineralization chamber, water is decomposed into H ⁺ and OH ⁻ by dehydration in addition to the movement of ions, and this is used as a cation exchanger and an anion exchanger in the third demineralization chamber 73. In addition to regeneration, OH ⁻ is also used for regeneration of the anion exchanger filled in the first and second desalting chambers 71 and 72, so that regeneration of the ion exchanger with acid and alkali is not necessary. Thus, the ion content in the desalination chamber inlet water 10 is sufficiently removed including the weak anion component, and the pure water 19 can be continuously obtained.
[0017]
Here, since the cation content is much easier to remove than the weak anion content, the cation content can usually be sufficiently removed only by the third demineralization chamber 73, but the cation content in the demineralization chamber inlet water 10 is sufficient. In the case where a large amount of components are contained, the ion exchanger filled in the third desalting chamber shown in FIG. The ion exchange membrane on the anode side of the second desalting chamber 72 is changed to the cation exchange membrane 6, and the ion exchanger filled in the second desalting chamber 72 is a mixture of a cation exchanger and an anion exchanger. With the ion exchanger, the ion exchanger in the third desalting chamber 73 is a cation exchanger, and the treated water flowing out from the first desalting chamber 71 is introduced into the third desalting chamber 73, Furthermore, it is introduced into the second desalting chamber 72 filled with an anion exchanger and a cation exchanger. Law may be increased removal capacity of the cation performed.
Further, in addition to the third desalting chamber 73 in this figure, a fourth desalting chamber may be further provided, and the outlet water of the third desalting chamber 73 may be further desalted.
[0018]
When the desalting chamber group 70 is configured using a desalting chamber in which a bipolar membrane is arranged on one side, an anion exchanger is installed in the desalting chamber formed by the anion exchange membrane and the bipolar membrane, Desalination efficiency is high when the inside of the desalination chamber formed by the membrane and the cation exchange membrane is filled with a cation exchanger.
Due to the characteristics of the bipolar membrane, H ⁺ and OH ⁻ are efficiently generated by hydrolysis at low voltage in the bipolar membrane, H ⁺ regenerates the cation exchanger, OH ⁻ regenerates the anion exchanger, It becomes possible to remove the ion content in the group inlet water 18.
Since hydrolysis can be efficiently generated, it is expected that the operating voltage is further reduced when a bipolar membrane is used.
In addition, in the electric regeneration type desalination apparatus, conventionally, a concentration chamber of ± 1 as many as the number of desalting chambers was necessary. As described above, the desalination chamber divided by a plurality of ion exchange membranes. By forming an electric regenerative desalination apparatus using the above, the number of concentration chambers can be reduced, and the operation voltage can be reduced accordingly.
[0019]
【Example】
Hereinafter, the present invention will be specifically described by way of examples.
Example 1
In this embodiment, the effect of the present invention will be described based on comparison with a comparative example. The test equipment is as shown in the flow chart of the test apparatus shown in FIG. 2, and Fujisawa city water is activated carbon as the desalination chamber inlet water 10, the concentration chamber inlet water 1, the cathode chamber inlet water 14, and the anode chamber inlet water 16. What was pre-processed with the filter, the safety filter, and the reverse osmosis membrane apparatus was used, and the water quality was a specific resistance of 0.25 MΩ · cm.
In this embodiment, the electric regeneration type desalination apparatus in the test apparatus shown in FIG. 2 uses the electric regeneration type desalination apparatus having the configuration shown in FIG. 1, and the flow rate of the desalination chamber inlet water 10 is 100 L / h. The flow rate of the salt chamber group inlet water 18 is 150 L / h, the flow rate of the concentration chamber inlet water 12 is 50 L / h, the flow rate of the cathode chamber inlet water 14 and the flow rate of the anode chamber inlet water 16 are each 10 L / h, and 0.4 A The direct current was applied to the cathode 1 and the anode 3 for operation.
[0020]
The electric regenerative desalination apparatus has an electrode area of 640 cm ² , 10 desalination chambers, 6 of which are used as two desalination chamber groups 70. The second desalting chamber 72 is formed on both sides with the anion exchange membrane 5, and the anion exchanger is formed inside, and the third desalting chamber 73 and the desalting chamber 7 are connected to the anion exchange membrane 5 and the cation exchange membrane 5. It was formed by the ion exchange membrane 6 and filled with an anion exchanger and a cation exchanger.
The concentrating chamber 8 has five chambers, and the cathode chamber 2 and the anode chamber 4 are provided at both ends.
Further, an anion exchanger and a cation exchanger are provided inside the concentrating chamber 8, a spacer having no electrical conductivity with the cation exchanger is provided inside the cathode chamber 2, and an anode chamber 4 is provided inside the anode chamber 4. The anion exchanger and a non-conductive spacer were filled.
As a result of operating under the above conditions, the desalting chamber group pure water 19 having a specific resistance of 17.7 MΩ · cm and a removal rate of carbonic acid and silica of about 99% from the desalting chamber group 70 is Desalination chamber outlet pure water 11 having a specific resistance of 14.2 MΩ · cm, a carbonation removal rate of 94%, and a silica removal rate of about 88% was continuously obtained.
[0021]
In the case of using two kinds of pure water having a high specific resistance and pure water that does not have to be so high, in the present invention, a desalting chamber in which a plurality of desalting chambers are formed without using a concentration chamber. By changing the number of rooms 70 and the number of demineralization chambers 7 with the concentrating chambers 8 on both sides and the flow rate of water, one electric regenerative demineralization apparatus can be used for specific resistances for two purposes. Of pure water can be obtained.
Since the number of concentrating chambers 8 is reduced to 5 compared with 9 in Comparative Example 1 below, the operating voltage was about 180 V, which was lower than that in Comparative Example 1.
In addition, when both the desalting chamber outlet pure water 11 and the desalting chamber group outlet pure water 19 are mixed and used, the quality of the mixed pure water is 16.0 MΩ · cm, and the carbonation removal rate is about Pure water having a specific resistance higher than that of Comparative Example 1 was obtained with 97% and a silica removal rate of about 95%.
[0022]
Comparative Example 1
As a comparative example, an electric regenerative desalination apparatus having the configuration shown in FIG. 3 is used, the flow rate of the desalination chamber inlet water 10 is 250 L / h, the flow rate of the concentration chamber inlet water 12 is 90 L / h, and the cathode chamber inlet water 14 The operation was performed by applying a direct current of 0.4 A to the cathode 1 and the anode 3 at a flow rate and a flow rate of the anode chamber inlet water 16 of 10 L / h, respectively.
The electric regenerative desalination apparatus has an electrode area of 640 cm ² , 10 desalination chambers, 9 concentrating chambers, a cathode chamber and an anode chamber at both ends, and an anion exchanger in the desalting chamber and the concentrating chamber. And the cation exchanger, the cathode chamber is filled with a cation exchanger, and the anode chamber is filled with an anion exchanger.
As a result of operating under the above conditions, pure water 11 having a specific resistance of about 14.4 MΩ · cm was continuously produced.
In this operation, the operation voltage was 210 V, the carbonation removal rate was 95%, and the silica removal rate was 88%.
[0023]
【The invention's effect】
According to the electric regenerative desalination apparatus of the present invention, as described above, the ability to remove weak anion components in the water to be treated can be increased to obtain pure water having a high specific resistance, and two kinds of water qualities different from each other. Of pure water can be supplied to the outside.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an example of an electric regeneration type desalination apparatus according to the present invention.
FIG. 2 is a flowchart of the test apparatus used in the examples.
FIG. 3 is a schematic configuration diagram showing an example of a conventional electric regenerative desalination apparatus.
[Explanation of symbols]
1: cathode, 2: cathode chamber, 3: anode, 4: anode chamber, 5: anion exchange membrane, 6: cation exchange membrane, 7: desalting chamber, 8: concentration chamber, 9: ion exchanger, 10 : Demineralization chamber inlet water, 11: Pure water, 12: Concentration chamber inlet water, 13: Concentration chamber outlet water, 14: Cathode chamber inlet water, 15: Cathode chamber outlet water, 16: Anode chamber inlet water, 17: Anode Room outlet water, 18: Desalination chamber group inlet water, 19: Pure water, 71: First desalination chamber constituting the desalination chamber group, 72: Second desalination chamber constituting the desalination chamber group, 73: Third desalting chamber constituting the desalting chamber group

Claims

A concentration chamber comprising a cathode chamber having a cathode and an anode chamber having an anode, and a cation exchange membrane on the anode side and an anion exchange membrane on the cathode side between the two electrode chambers; (A) to (e) of the desalting chamber, (a) a cation exchange membrane on the cathode side, an anion exchange membrane on the anode side, and an ion exchanger inside, (b) (C) a desalting chamber in which cation exchange membranes are arranged on both sides and filled with an ion exchanger inside; (c) a desalting chamber in which anion exchange membranes are arranged on both sides and filled with an ion exchanger; A cation exchange membrane on the cathode side, a bipolar membrane on the anode side, a desalination chamber filled with an ion exchanger inside, (e) a bipolar membrane on the cathode side, and an anion exchange membrane on the anode side, An electrically regenerative desalination constructed by disposing one or more kinds of desalting chambers, each of which is filled with an ion exchanger The desalting chamber is a desalting chamber in which concentrating chambers are disposed on both sides, and a plurality of any one or more types of desalting chambers are adjacent to each other without interposing a concentrating chamber. An electric regenerative desalination apparatus characterized by having at least one arranged desalination chamber group.

In the desalination chamber group arranged without using a concentrating chamber therebetween, the water to be treated introduced into the first desalination chamber constituting the desalination chamber group is transferred from the first desalination chamber to the desalination chamber. 2. The electric regenerative desalination apparatus according to claim 1, wherein the electric regenerative desalination apparatus is connected so that water is sequentially passed in series until the final desalting chamber constituting the chamber group is desalted.

The ion exchanger filled in the desalting chamber of (a) is an anion exchanger, a cation exchanger, or an ion exchanger of both an anion exchanger and a cation exchanger, (b) The ion exchanger filled in the desalting chamber is a cation exchanger, the ion exchanger filled in the desalting chamber of (c) is an anion exchanger, and the deionization of (d) is performed. The ion exchanger filled in the salt chamber is a cation exchanger, and the ion exchanger filled in the desalting chamber of (e) is an anion exchanger. 2. The electric regenerative desalination apparatus according to 2.

The electric regenerative desalination apparatus according to claim 1, 2 or 3, wherein the ion exchanger is an ion exchanger made of an ion exchange fiber into which an ion exchange group is introduced by a radiation graft polymerization method.

5. The electric regeneration type desalination apparatus according to claim 4, wherein the ion exchanger made of the ion exchange fiber is a nonwoven fabric or a woven fabric, and a mesh-like spacer.