JP3907012B2 - Counter-current regenerative ion exchange apparatus and regeneration method thereof - Google Patents
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【０００１】
【発明の属する技術分野】
本発明は、イオン交換装置に係わり、特に強型イオン交換樹脂、及び弱型イオン交換樹脂を一塔の樹脂塔内に充填し、下降流通水・上昇流通薬を行う向流再生式イオン交換装置とその再生方法に関するものである。
【０００２】
【従来の技術】
強・弱型イオン交換樹脂を一塔内に充填し、通水を弱→強型イオン交換樹脂、再生を強→弱型イオン交換樹脂で行う向流再生式イオン交換装置は再生効率が高く、近年採用例が多い。しかし、向流再生式の特長を発揮するには強・弱型イオン交換樹脂を２層に分離・維持する必要がある。強・弱型イオン交換樹脂が混合すると処理水質不良、採水量不足等のトラブルが発生する。一方、向流再生では通水時、及び通薬時にイオン交換樹脂層を固定床に維持する必要も有する。特に、処理水水質を左右する強型イオン交換樹脂を如何に固定床に維持するかが開発の重要なポイントとなる。
【０００３】
向流再生式イオン交換装置は下降流通水・上昇流通薬を行うものと、上昇流通水・下降流通薬を行うものに大別される。弱型イオン交換樹脂と強型イオン交換樹脂とでは、弱型イオン交換樹脂の方が比重が小さい。上昇流通水・下降流再生を行うには比重が小さい弱型イオン交換樹脂を樹脂塔下部に充填するため樹脂塔内部に物理的な仕切（中間隔壁）を設けなくては強・弱型イオン交換樹脂を２層に分離・維持できないのに対し、下降流通水・上昇流通薬では中間隔壁が無くても樹脂の比重差により２層に分離・維持できる特長がある。しかし強・弱型イオン交換樹脂の比重差は常に完全な分離が可能となるほど十分なものではない。両樹脂とも通水により負荷形となった場合、あるいは弱型アニオン交換樹脂が有機物を吸着して重くなった場合等では比重差がなくなり、分離不能となる。中間隔壁が無い装置ではトラブル発生の危険性を内在している。
【０００４】
従来の下降流通水・上昇流通薬を行う向流再生式イオン交換装置は、中間隔壁が無くても樹脂の比重差により２層に分離・維持できるというこの方式の特長を生かすため、主として中間隔壁無しで強・弱型イオン交換樹脂を２層に分離・維持する方向での改善がなされてきた。具体的な方法としては、▲１▼強・弱型イオン交換樹脂の比重差に加え、粒径差も付けて分離を良くする方法、▲２▼比重差の大きい再生形の状態で逆洗分離する方法、▲３▼弱型イオン交換樹脂のみを再生後、逆洗分離する方法等が考案されている。しかし▲１▼の方法では強・弱型イオン交換樹脂の組み合わせが制限され、また粒径差を付けるために大粒径となった強型イオン交換樹脂の再生が十分とならず、再生効率が低下・処理水水質の悪化が生じる。▲２▼、▲３▼の方法でも再生剤の有効利用が妨げられ、再生効率が低下する。
【０００５】
樹脂塔内に中間隔壁を設ける方法は、上昇流通水・下降流通薬を行う向流再生式イオン交換装置のみが実用化されている。下降流通水・上昇流通薬を行う向流再生式イオン交換装置でも中間隔壁を設ける方法は、若干提案されているが実用化されているものは殆ど無い。これまでに提案された具体的な方法としては、▲４▼強・弱型イオン交換樹脂を充填した塔を単に重ねたような構造で、それぞれが逆洗用の大きな空間（フリーボード）を持ったものを上昇流通薬する方法、▲５▼２塔を重ねた塔構造で、強型イオン交換樹脂層上部に中間集水管を埋設し、上昇流通薬時には上部から水を導入して中間集水管から排水することにより、樹脂塔下部に強型イオン交換樹脂の固定床を形成し、再生廃液は回収タンクに回収し、回収した再生廃液をポンプを使用して弱型イオン交換樹脂に通薬して再生する方法、▲６▼樹脂塔内部に上下に可動の中間隔壁を設置し、逆洗時には中間隔壁を上方に移動させて逆洗し、通薬時には中間隔壁を下方に移動させて樹脂塔下部に強型イオン交換樹脂を押しつけて固定床を形成する方法等がある。しかしこれらの方法では、上下２室に逆洗用のフリーボードを持たせた場合には樹脂塔高が高くなり、また中間隔壁の他に固定床維持のために複雑な機構・操作が必要となる等、実際に実用化されているものは殆ど無いのが現状である。
【０００６】
【発明が解決しようとする課題】
中間隔壁無しで強・弱型イオン交換樹脂を２層に分離・維持する方法では、いずれにしても完全な分離・維持は不可能で、従来技術▲１▼〜▲３▼での改善は再生効率の低下等の問題点を伴い、また強・弱型イオン交換樹脂の組み合わせも限られる。中間隔壁を設けた▲４▼〜▲６▼では樹脂塔高が高くなり、複雑な機構や再生操作が必要となる等の問題点を持ち、実用化されたものが無い。中間隔壁を設けたものでは、上昇流通水・下降流通薬のみが実用化されているが、この方式では通水時に通水の中断によりイオン交換樹脂層が乱れ、処理水質が悪化し易い問題点を持つ。
本発明は、これらの従来技術が持つ問題点を一挙に解決し、強・弱型イオン交換樹脂の分離・維持が完全で、簡単な機構・操作により下降流通水・上昇流通薬を行う向流再生式イオン交換装置とその再生方法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、本発明では、強型イオン交換樹脂及び弱型イオン交換樹脂を充填した樹脂塔に下降流通水・上昇流通薬を行う向流再生式イオン交換装置において、樹脂塔の上部と下部に一対の集水装置を設け、下部集水装置の上部には順次下から上に向って、強型イオン交換樹脂を充填した充填部、該イオン交換樹脂層高の２〜１５％のフリーボードを介して強型イオン交換樹脂より大粒径で且つ、強型イオン交換樹脂を保持できる大きさで比重が１より小さい不活性樹脂を充填した充填部、塔中間部に水は通すがイオン交換樹脂は通さない中間隔壁、弱型イオン交換樹脂を充填した充填部、該イオン交換樹脂層高の２〜１５％のフリーボードを介して弱型イオン交換樹脂より大粒径で且つ、弱型イオン交換樹脂を保持できる大きさで比重が１より小さい不活性樹脂を充填した充填部が配備され、その上部に上部集水装置が配され、前記下部集水装置には処理水流出弁、逆洗水流入弁、再生剤流入弁及び洗浄弁を有する集配水管が接続され、また上部集水装置には原水流入弁及び再生排水流出弁を有する集配水管が接続されていることとしたものである。
【０００８】
前記強型イオン交換樹脂は、弱型イオン交換樹脂の粒径とほぼ同等か、それより小さいものを使用するのが良い。
また本発明では前記の向流再生式イオン交換装置の再生方法において、下記（ａ）〜（ｅ）の工程を順次行い樹脂を再生することとしたものである。
（ａ）下部集水装置からの高流速逆洗により強・弱型イオン交換樹脂の大部分をそれぞれ不活性樹脂層に押しつけ、通水時に蓄積した懸濁物質を不活性樹脂層を経由して上部集水設備から排出除去すると共に、強・弱型イオン交換樹脂の固定床を形成する工程
（ｂ）高流速逆洗に引き続き、高流速逆洗より低速で且つ、（ａ）で形成された固定床を維持するに必要な流速で再生剤を下部集水装置から通薬する工程
（ｃ）通薬に引き続き、通薬工程（ｂ）とほぼ同じ流速で下部集水装置から処理水を通水し、残留する再生剤を有効に利用する押出工程
（ｄ）押出終了後、通水を停止し、再生された樹脂を自由に落下させる沈整工程（ｅ）上部集水装置から下降流で通水して樹脂を洗浄する洗浄工程。
【０００９】
【発明の実施の形態】
以下に本発明の実施形態を示した図１によって本発明の詳細を説明する。
本発明では、樹脂塔１の中間部に水は通すが、イオン交換樹脂を通さない中間隔壁２が設けられており、樹脂塔の上下に一対の集水装置３、４を設け、下部集水装置３の上部に強型イオン交換樹脂５を充填し、更にその上部には強型イオン交換樹脂層高の２〜１５％のフリーボード６を介して強型イオン交換樹脂より大粒径で且つ、強型イオン交換樹脂を保持できる大きさで比重が１より小さい不活性樹脂７を充填する。その上に中間隔壁２を設け、その上部には弱型イオン交換樹脂８を充填し、更にその上部には弱型イオン交換樹脂層高の２〜１５％のフリーボード９を介して弱型イオン交換樹脂より大粒径で且つ、弱型イオン交換樹脂を保持できる大きさで比重が１より小さい不活性樹脂１０が充填され、その上に上部集水装置４が設けられている。そして下部集水装置には処理水流出弁１３、逆洗水流入弁１４、再生剤流入弁１５、洗浄弁１６を有する集配水管が接続されており、上部集水装置４には原水流入弁１１、再生排水流出弁１２を有する集配水管が接続されている。
【００１０】
再生に際しては
（ａ）逆洗水流入弁１４、再生排水流出弁１２を開き、下部集水装置３からの高流速逆洗により強型イオン交換樹脂５の大部分を不活性樹脂層７に、弱型イオン交換樹脂８の大部分が不活性樹脂層１０に押しつけ、通水時に蓄積した懸濁物質を不活性樹脂層１０を経由して上部集水装置４から排出除去すると共に、強型イオン交換樹脂５、弱型イオン交換樹脂８の固定床を形成する高流速逆洗工程
（ｂ）高流速逆洗に引き続き、逆洗水流入弁１４を閉じ、再生剤流入弁１５を開くことにより高流速逆洗より低速で且つ、（ａ）で形成された固定床を維持するに必要な流速で再生剤を下部集水装置３から通薬する工程
（ｃ）通薬に引き続き、通薬工程とほぼ同じ流速で下部集水装置３から処理水を通水し、残留する再生剤を有効に利用する押出工程
（ｄ）押出終了後、再生剤流入弁１５、再生排水流出弁１２に閉じ、押出を停止し、再生された樹脂を自由に落下させる沈整工程
（ｅ）原水流入弁１１、洗浄弁１６を開き、上部集水装置４から下降流で原水を通水して樹脂を洗浄する洗浄工程
の５工程により樹脂を再生する。
【００１１】
工程（ａ）の高流速逆洗は本発明独自のもので、イオン交換樹脂の固定床を実質的に維持したまま、短時間の内に上部に移動させる。この時に必要な逆洗流速はイオン交換樹脂の種類、フリーボードの割合等により異なる。一例を挙げるとフリーボード１０％の場合強型カチオン交換樹脂でＬＶ２０〜２６ｍ／ｈ程度以上、強型アニオン交換樹脂でＬＶ１４〜２０ｍ／ｈ程度以上が必要である。これ以下の逆洗流速ではイオン交換樹脂層の下部が流動層となる割合が増加する。固定床として維持される割合が減じると向流再生の効果が充分に発揮されず、処理水質が悪化する。
本発明においてフリーボードの割合の選択は重要で、小さ過ぎると樹脂の膨潤を吸収しきれない場合が生じる可能性が有り、大き過ぎると高流速逆洗の工程でイオン交換樹脂層の下部が流動層となる割合が増加し、処理水質悪化の危険性が増加する。フリーボードとしてはイオン交換樹脂の最大層高の２〜１５％とするのが適切である。高流速逆洗に使用する水は原水でも良いが、イオン交換樹脂層下部に無用のイオン負荷を与え、処理水質悪化の原因となるので処理水を使用するのが好ましい。
【００１２】
本発明において工程（ａ）はイオン交換樹脂の固定床を形成する他にも重要な役割を持っている。即ち高流速逆洗によりイオン交換樹脂層が上方に移動し、不活性樹脂層にぶつかって止まる衝撃で、通水時にイオン交換樹脂層表面に蓄積した懸濁物質がイオン交換樹脂層からはずれ、不活性樹脂層を経由して上部集水装置から高濃度で排出除去される。従来の逆洗が懸濁物質の排出に１０〜２０分程度必要であるのと比較して、本発明では従来の逆洗とは全く異なった原理で懸濁物質が排出されるため、１〜３分程度と極めて短時間で終了する。また本発明では再生毎に高流速逆洗を行うため、懸濁物質の蓄積も生じ難い。
本発明において不活性樹脂の粒径選択は重要で、細か過ぎると懸濁物質の排出除去が不十分となり易く、大きすぎるとイオン交換樹脂のリーク、あるいは上部集水装置の目詰まりの危険性を生じる。不活性樹脂の粒径としてはイオン交換樹脂の有効径の２〜８倍のものを使用することが必要である。不活性樹脂層高としては１００〜４００ｍｍが適切である。
【００１３】
工程（ａ）の高流速逆洗で一度形成された固定層は、逆洗流速を下げても固定床が維持できる。本発明では工程（ｂ）の通薬流速を固定床が維持できる必要最小限以上で通薬することにより、固形床の維持とイオン交換樹脂と再生剤の接触時間の両立を図っている。固定床が維持できる限界の通薬流速の一例は強型カチオン交換樹脂で８ｍ／ｈ程度以上、強型アニオン交換樹脂で４ｍ／ｈ程度以上である。本発明でも通薬中にイオン交換樹脂の収縮が起こるが、通薬流速を固定床が維持できる限界流速以上としているため、収縮による流動層の発生は全く認められず、固定床下端部が収縮した分だけ上方に移動する。即ち従来法では多大の工夫を要していた「通薬時のイオン交換樹脂の収縮による流動層の発生を防止」が、本発明では工程（ａ）の高流速逆洗と、それに引き続く工程（ｂ）の固定床が維持できる必要最小限以上の流速で通薬するという簡単な操作だけで達成されている。
【００１４】
工程（ｃ）の押出は従来法と特に変わった点は無いが、工程（ｄ）の沈整は本発明独自のものである。即ち押出工程ではイオン交換樹脂層は不活性樹脂層に押しつけられて固定床を形成しているが、押出停止と共に固定床下部から順次崩壊し、下部集水装置の上に積層する。新たに形成された固定床は再生後のイオン交換帯をほぼ保っているため、通水時に処理水質が悪化することはない。
本発明ではこの工程によりイオン交換樹脂の全層が再生毎にほぐされ、固着等が解消されるため、イオン交換樹脂層の差圧増加が極めて生じ難い。またイオン交換樹脂層内に入り込んだ懸濁物質、イオン交換樹脂の破砕によって生じた破片等がイオン交換樹脂層が順次崩壊する過程で固定床下部から樹脂塔上方に移送され、次回の再生で塔外に排出される確率が高くなる効果も生じる。
工程（ｅ）の洗浄は従来法と特に変わった点は無いが、フリーボードが少ないこと及び工程（ｄ）でイオン交換樹脂層の固着が解消されることから、洗浄に要する時間が短く、洗浄に要する水量も少なくなる傾向が認められる。
【００１５】
本発明では中間隔壁を持つことにより、強・弱型イオン交換樹脂の分離・維持が完全となるため、樹脂の組み合わせの制限も無く、任意の最適な樹脂を組み合わすことができる。特に中間隔壁を使用しない場合には組み合わすことが不可能である比較的小粒径の強型イオン交換樹脂が使用可能となる特徴を持つ。
向流再生では通薬時にイオン交換樹脂層を固定床に維持する必要が有り、特に処理水水質を左右する強型イオン交換樹脂を固定床に維持することが重要となる。本発明ではイオン交換樹脂は高流速逆洗により不活性樹脂層を介して樹脂塔上部に固定床を形成するが、小粒径の強型イオン交換樹脂を使用することにより固定床に維持するに必要な最低流速が小さくなり、固定床の維持が容易となる。またこの効果に加え、小粒径の強型イオン交換樹脂は大粒径のものより再生し易く、低い再生剤濃度、短い再生剤接触時間でも十分な再生が可能となるため、固定床を維持するための通薬流速、再生剤濃度、再生剤接触時間の全ての条件を満足することが容易となる。
【００１６】
本発明ではイオン交換樹脂は高流速逆洗により不活性樹脂層を介して樹脂塔上部に固定床を形成するので、樹脂塔下部に固定床を形成する従来装置の様に複雑な装置・操作が不要となり、樹脂塔内には中間隔壁の他には何も無く、よりシンプルな装置となっている。また樹脂塔のフリーボードはイオン交換樹脂層高の２〜１５％と少なく、不活性樹脂を充填することを考慮に入れても従来の中間隔壁を持つ樹脂塔より樹脂塔高を低くでき、コンパクトな装置となっている。
【００１７】
【実施例】
以下に本発明を実施例により具体的に説明する。
実施例１
内径６０ｍｍ、高さ２０００ｍｍの樹脂塔の下から１２００ｍｍの所に多孔板にサランネットを張った中間隔壁を設けて樹脂塔を２分割し、下室には強型カチオン樹脂ダウエックス ＨＧＲ−Ｗ２（有効径０．６２ｍｍ）をＨ形で層高１０１５ｍｍ充填し、その上に不活性樹脂ダウエックスＩＦ−６２（径２．５〜３．５ｍｍ）を１３０ｍｍ充填した。フリーボードは５５ｍｍで強型カチオン樹脂層高の５．４％に相当する。
【００１８】
上室には弱型カチオン樹脂ダウエックス ＭＡＣ−３（有効径０．５３ｍｍ）をＨ形で層高６２５ｍｍ充填し、その上に不活性樹脂ダウエックスＩＦ−６２（径２．５〜３．５ｍｍ）を１００ｍｍ充填した。フリーボードは７５ｍｍで弱型カチオン樹脂層高の１２％に相当する。
この樹脂塔に表１に示すイオン組成の原水を６０リットル／ｈでカチオンブレーク（エンドポイント１０μＳ／ｃｍ）まで通水し、通水後は表２に示す再生条件で再生した。
強型カチオン樹脂層： ２．６リットル（基準形）、
弱型カチオン樹脂層： １．６リットル（基準形）、
再生レベル： ８１．５ｇ−ＨＣｌ／リットル−強樹脂、
【００１９】
【表１】
【表２】
この条件で通水・再生を４０サイクル繰り返した結果を表３に示す。通薬時間が１０分と短いためカチオン塔の処理水質は若干悪いが、４０サイクル後においても採水量は８００リットル前後とほぼ一定で、再生効率はほぼ９３％と良好であった。
【表３】
実施例２
強型カチオン樹脂としてダウエックス ＨＧＲ−Ｗ２の替わりに０．７ｍｍ以上の大粒径を除いたダウエックス ＨＧＲ−Ｗ２（有効径０．５０ｍｍ）を充填した他は、実施例１と同一の条件で通水・再生を４０サイクル繰り返した。結果を表４に示す。
通薬時間が１０分と短いにも関わらず、カチオン塔の処理水質は実施例１より良好であった。採水量は８３０リットル前後とほぼ一定で、再生効率はほぼ９６％と良好であった。
【００２３】
【表４】
比較例１
中間隔壁を除いた内径６０ｍｍ、高さ２０００ｍｍの樹脂塔に強型カチオン樹脂として０．７ｍｍ以上の大粒径を除いたダウエックス ＨＧＲ−Ｗ２をＨ形で層高１０１５ｍｍ充填し、その上に弱型カチオン樹脂ダウエックス ＭＡＣ−３をＨ形で層高６２５ｍｍ充填した。この樹脂塔に表１の原水を８４０リットル通水後、逆洗したところ、強型カチオン樹脂と弱型カチオン樹脂は完全に混合した。混合状態の樹脂に５％ＨＣｌ ６．３リットルを下降流で通薬して樹脂を再生後、再度逆洗したが強型カチオン樹脂と弱型カチオン樹脂は混合したままで２層に分離することはできなかった。
【００２５】
【発明の効果】
本発明によれば従来の強・弱型イオン交換樹脂を１塔内に充填した向流再生式イオン交換装置の持つ欠点、即ち▲１▼強・弱型イオン交換樹脂の混合による処理水水質の悪化、及び採水量の低下、▲２▼強・弱型イオン交換樹脂の組み合わせの制限、▲３▼通水中断による処理水水質の悪化、▲４▼装置・再生操作の複雑化等が一挙に解決できる。その結果、シンプルでコンパクトなイオン交換装置、及び簡単で短時間に終了する再生方法を提供でき、良好な処理水質を安価にかつ安定的に得ることができる。
【図面の簡単な説明】
【図１】本発明の実施態様の１例を示すイオン交換塔の概略図。
【符号の説明】
１：樹脂塔、２：中間隔壁、３：下部集水装置、４：上部集水装置、５：強型イオン交換樹脂、６：フリーボード、７：不活性樹脂、８：弱型イオン交換樹脂、９：フリーボード、１０：不活性樹脂、１１：原水流入弁、１２：再生排水流出弁、１３：処理水流出弁、１４：逆洗水流入弁、１５：再生剤流入弁、１６：洗浄弁、[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ion exchange device, and more particularly, a countercurrent regenerative ion exchange device that fills a single resin tower with a strong ion exchange resin and a weak ion exchange resin and performs downward flow water and upward flow medicine. And its reproduction method.
[0002]
[Prior art]
A counter-current regenerative ion exchange device that fills a tower with strong and weak ion exchange resin and conducts water with weak → strong ion exchange resin and regeneration with strong → weak ion exchange resin has high regeneration efficiency. There are many examples of adoption in recent years. However, it is necessary to separate and maintain the strong / weak ion exchange resin in two layers in order to exhibit the features of the countercurrent regeneration type. When strong and weak ion exchange resins are mixed, troubles such as poor treatment water quality and insufficient water sampling occur. On the other hand, in countercurrent regeneration, it is also necessary to maintain the ion exchange resin layer on a fixed bed during water flow and drug flow. In particular, an important point of development is how to maintain a strong ion exchange resin that influences the quality of treated water on a fixed bed.
[0003]
Counter-current regenerative ion exchangers are broadly classified into those that perform downward circulating water / upward flowing medicine and those that perform upward circulating water / downward flowing medicine. Of the weak ion exchange resin and the strong ion exchange resin, the weak ion exchange resin has a lower specific gravity. In order to recycle up-flow water and down-flow, weak ion exchange resin with low specific gravity is filled in the lower part of the resin tower, so there is no need to provide a physical partition (intermediate partition wall) inside the resin tower. While the resin cannot be separated / maintained in two layers, the downward flowing water / upward flowing medicine has the advantage that it can be separated / maintained in two layers due to the difference in specific gravity of the resin without an intermediate partition. However, the specific gravity difference between strong and weak ion exchange resins is not always sufficient to allow complete separation. When both resins are loaded due to water flow, or when the weak anion exchange resin adsorbs organic matter and becomes heavy, the difference in specific gravity disappears and separation becomes impossible. A device without an intermediate bulkhead has a risk of trouble.
[0004]
Conventional counter flow regenerative ion exchangers that use down-flowing water and ascending-flow medicines can be separated and maintained in two layers by the difference in specific gravity of the resin even without an intermediate partition. Improvements have been made in the direction of separating and maintaining the strong / weak ion-exchange resin in two layers without using any material. Specific methods include (1) a method of improving separation by adding a particle size difference in addition to the specific gravity difference of strong and weak ion exchange resins, and (2) backwash separation in a regenerative state with a large specific gravity difference. And (3) a method of regenerating only the weak ion exchange resin and then back-separating it. However, in the method (1), the combination of strong and weak ion exchange resins is limited, and the strong ion exchange resin having a large particle size due to the difference in particle size cannot be sufficiently regenerated, resulting in a high regeneration efficiency. Deterioration / deterioration of treated water occurs. In the methods (2) and (3), the effective use of the regenerant is hindered and the regeneration efficiency is lowered.
[0005]
As a method for providing an intermediate partition wall in a resin tower, only a counter-current regenerative ion exchange apparatus that performs ascending water and descending medicine has been put into practical use. Even in a counter-current regenerative ion exchanger that performs down-flow water / up-flow medicine, methods for providing an intermediate partition have been proposed to some extent, but few have been put into practical use. The concrete methods proposed so far include (4) a structure in which towers packed with strong and weak ion exchange resins are simply stacked, each having a large space for backwashing (free board). Ascending flow medicine, (5) In the tower structure with two towers stacked, an intermediate water collection pipe is embedded in the upper part of the strong ion exchange resin layer, and water is introduced from the upper part during the upward flow medicine. By draining the waste water, a fixed bed of strong ion exchange resin is formed at the bottom of the resin tower, the recycled waste liquid is collected in a collection tank, and the collected recycled waste liquid is passed through the weak ion exchange resin using a pump. (6) A movable intermediate partition wall is installed inside and below the resin tower. During backwashing, the intermediate partition wall is moved upward to perform backwashing. Forming a fixed bed by pressing strong ion exchange resin on the bottom There is that method and the like. However, in these methods, when the freeboard for backwashing is provided in the upper and lower two chambers, the height of the resin tower becomes high, and in addition to the intermediate partition, complicated mechanisms and operations are required to maintain the fixed floor. At present, there are few things that are actually put into practical use.
[0006]
[Problems to be solved by the invention]
In the method of separating and maintaining the strong / weak ion exchange resin in two layers without an intermediate partition, it is impossible to completely separate and maintain anyway, and the improvements in the conventional techniques (1) to (3) are regenerated. This is accompanied by problems such as a decrease in efficiency, and the combination of strong and weak ion exchange resins is also limited. In (4) to (6) provided with an intermediate partition wall, the height of the resin tower becomes high, and there are problems such as requiring a complicated mechanism and a regenerating operation, and none has been put to practical use. In the case where an intermediate partition is provided, only ascending water and descending medicine are put into practical use, but this method has a problem that the quality of treated water tends to deteriorate due to disturbance of the ion exchange resin layer due to interruption of the water flow during water flow. have.
The present invention solves these problems of the prior art at once, complete separation and maintenance of strong and weak ion-exchange resins, and countercurrent flow that performs downward flow water and upward flow medicine with a simple mechanism and operation. It is an object of the present invention to provide a regenerative ion exchange apparatus and a regeneration method thereof.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, in the present invention, in the countercurrent regenerative ion exchange apparatus that performs downward flow water and upward flow medicine on a resin tower filled with a strong ion exchange resin and a weak ion exchange resin, the upper part of the resin tower A pair of water collecting devices are provided at the bottom, and the upper portion of the lower water collecting device is sequentially filled from the bottom to the top, filled with a strong ion exchange resin, 2-15% of the ion exchange resin layer height. Water passes through a freeboard through a packed section filled with an inert resin having a particle size larger than that of the strong ion exchange resin and having a specific gravity smaller than 1 and capable of holding the strong ion exchange resin. It has a larger particle size and weaker than the weak ion exchange resin through an intermediate partition through which the ion exchange resin does not pass, a filling portion filled with the weak ion exchange resin, and a free board of 2 to 15% of the height of the ion exchange resin layer. Large enough to hold a type ion exchange resin A filling section filled with an inert resin having a specific gravity of less than 1 is provided, and an upper water collecting device is arranged on the upper portion, and a treated water outflow valve, a backwash water inflow valve, and a regenerant inflow into the lower water collection device. A water collection / distribution pipe having a valve and a washing valve is connected, and a water collection / distribution pipe having a raw water inflow valve and a regeneration drainage outflow valve is connected to the upper water collection device.
[0008]
As the strong ion exchange resin, it is preferable to use a resin having a particle size substantially equal to or smaller than that of the weak ion exchange resin.
In the present invention, in the regeneration method of the counter-current regeneration type ion exchange apparatus, the following steps (a) to (e) are sequentially performed to regenerate the resin.
(A) Most of the strong and weak ion exchange resins are pressed against the inert resin layer by backwashing at a high flow rate from the lower water collecting device, and the suspended substances accumulated during water flow are passed through the inert resin layer. A step of forming a fixed bed of strong / weak ion exchange resin while discharging and removing from the upper water collecting facility (b) Following the high flow rate backwash, the flow rate was lower than that of the high flow rate backwash and formed in (a). Subsequent to the step (c) of passing the regenerant from the lower water collecting device at a flow rate necessary to maintain the fixed bed, the treated water is passed from the lower water collecting device at approximately the same flow rate as the drug passing step (b). Extrusion step that effectively waters and uses the remaining regenerant (d) After extrusion, water flow is stopped and the regenerated resin is dropped freely (e) Downstream from the upper water collecting device A cleaning process in which the resin is washed by passing water.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Details of the present invention will be described below with reference to FIG. 1 showing an embodiment of the present invention.
In the present invention, an
[0010]
At the time of regeneration, (a) the backwash
[0011]
The high flow rate backwashing in the step (a) is unique to the present invention, and is moved to the upper part within a short time while substantially maintaining the fixed bed of the ion exchange resin. The backwash flow rate required at this time varies depending on the type of ion exchange resin, the ratio of free board, and the like. For example, in the case of 10% free board, a strong cation exchange resin requires about LV 20 to 26 m / h or more, and a strong anion exchange resin requires about
In the present invention, it is important to select the ratio of the free board. If it is too small, the swelling of the resin may not be absorbed. If it is too large, the lower part of the ion exchange resin layer flows in the high flow rate back washing process. The ratio of stratification increases and the risk of deterioration of treated water quality increases. The free board is suitably 2 to 15% of the maximum layer height of the ion exchange resin. The water used for the high flow rate backwashing may be raw water, but it is preferable to use treated water because it gives unnecessary ion load to the lower part of the ion exchange resin layer and causes deterioration of treated water quality.
[0012]
In the present invention, step (a) has an important role in addition to forming a fixed bed of ion exchange resin. In other words, due to the impact that the ion exchange resin layer moves upward due to high-flow backwashing and hits the inert resin layer and stops, the suspended substances accumulated on the surface of the ion exchange resin layer during water flow come off from the ion exchange resin layer and become inactive. It is discharged and removed at a high concentration from the upper water collecting device via the active resin layer. Compared with the case where the conventional backwashing requires about 10 to 20 minutes for the discharge of the suspended solids, the present invention discharges the suspended solids on a principle completely different from the conventional backwashing. The process is completed in a very short time of about 3 minutes. In the present invention, since high flow backwashing is performed for each regeneration, accumulation of suspended solids hardly occurs.
In the present invention, it is important to select the particle size of the inert resin. If the particle size is too fine, discharge and removal of suspended solids are likely to be insufficient. If the particle size is too large, there is a risk of leakage of the ion exchange resin or clogging of the upper water collecting device. Arise. As the particle diameter of the inert resin, it is necessary to use a particle having an effective diameter of 2 to 8 times that of the ion exchange resin. The height of the inert resin layer is suitably 100 to 400 mm.
[0013]
The fixed bed once formed by the high flow rate backwashing in the step (a) can maintain the fixed bed even if the backwashing flow rate is lowered. In the present invention, by maintaining the flow rate of the drug in step (b) at a level that is more than the minimum necessary for maintaining the fixed bed, both the maintenance of the solid bed and the contact time of the ion exchange resin and the regenerant are achieved. An example of the maximum drug flow rate that can maintain the fixed bed is about 8 m / h or more for a strong cation exchange resin and about 4 m / h or more for a strong anion exchange resin. Even in the present invention, the ion exchange resin shrinks during the feeding, but since the feeding flow rate is higher than the limit flow rate at which the fixed bed can be maintained, the generation of a fluidized bed due to the shrinkage is not observed at all, and the lower end of the fixed bed shrinks. Move upward by that amount. That is, “preventing the generation of a fluidized bed due to shrinkage of the ion exchange resin at the time of drug delivery”, which required a great deal of contrivance in the conventional method, is the present invention, the high flow rate backwashing in step (a) and the subsequent steps ( This is achieved only by a simple operation of passing the medicine at a flow rate exceeding the minimum necessary to maintain the fixed bed of b).
[0014]
The extrusion in step (c) is not particularly different from the conventional method, but the settling in step (d) is unique to the present invention. That is, in the extrusion process, the ion exchange resin layer is pressed against the inert resin layer to form a fixed bed, but when the extrusion is stopped, the ion exchange resin layer sequentially collapses from the bottom of the fixed bed and is laminated on the lower water collecting device. Since the newly formed fixed bed substantially maintains the ion exchange zone after regeneration, the quality of the treated water does not deteriorate during water flow.
In the present invention, the entire layer of the ion exchange resin is loosened every time it is regenerated by this process, and sticking and the like are eliminated. In addition, suspended substances that have entered the ion exchange resin layer and fragments generated by crushing the ion exchange resin are transferred from the lower part of the fixed bed to the upper part of the resin tower in the course of the collapse of the ion exchange resin layer. There is also an effect of increasing the probability of being discharged outside.
The cleaning in step (e) is not particularly different from the conventional method, but the time required for cleaning is short because there are few free boards and the fixation of the ion exchange resin layer is eliminated in step (d). There is a tendency for the amount of water required to be reduced.
[0015]
In the present invention, since the separation and maintenance of the strong / weak ion exchange resin is completed by having the intermediate partition wall, any optimum resin can be combined without any limitation of the resin combination. In particular, a strong ion exchange resin having a relatively small particle size, which cannot be combined when an intermediate partition is not used, has a feature that it can be used.
In counter-current regeneration, it is necessary to maintain the ion exchange resin layer on a fixed bed at the time of drug delivery. In particular, it is important to maintain a strong ion exchange resin that affects the quality of treated water on the fixed bed. In the present invention, the ion exchange resin forms a fixed bed on the upper part of the resin tower through an inert resin layer by backwashing at a high flow rate. However, by using a strong ion exchange resin having a small particle size, the ion exchange resin is maintained on the fixed bed. The required minimum flow rate is reduced and the maintenance of the fixed bed is facilitated. In addition to this effect, strong ion exchange resins with small particle sizes are easier to regenerate than those with large particle sizes, and can be fully regenerated even with low regenerant concentration and short regenerant contact time, thus maintaining a fixed bed. Therefore, it becomes easy to satisfy all the conditions of the flow rate of the medicine to be used, the concentration of the regenerant and the contact time of the regenerant.
[0016]
In the present invention, the ion exchange resin forms a fixed bed at the upper part of the resin tower through the inert resin layer by backwashing at a high flow rate, so that complicated apparatus / operation like a conventional apparatus for forming a fixed bed at the lower part of the resin tower is possible. It becomes unnecessary, and there is nothing other than the intermediate partition in the resin tower, and the apparatus is simpler. Also, the resin tower freeboard is 2 to 15% less than the ion exchange resin layer height, and the resin tower height can be made lower than that of the conventional resin tower with an intermediate partition even when taking into account filling with inert resin. Device.
[0017]
【Example】
Hereinafter, the present invention will be described specifically by way of examples.
Example 1
An intermediate partition wall with a salannet stretched over a perforated plate is provided at a position 1200 mm from the bottom of a resin tower having an inner diameter of 60 mm and a height of 2000 mm, and the resin tower is divided into two parts. An effective diameter of 0.62 mm) was filled in an H shape with a layer height of 1015 mm, and an inert resin Dowex IF-62 (diameter 2.5 to 3.5 mm) was filled thereon with 130 mm. The free board is 55 mm and corresponds to 5.4% of the height of the strong cationic resin layer.
[0018]
The upper chamber is filled with weak cationic resin Dowex MAC-3 (effective diameter 0.53 mm) in an H shape with a layer height of 625 mm, and an inert resin Dowex IF-62 (diameter 2.5 to 3.5 mm) is placed on it. ) 100 mm. The free board is 75 mm and corresponds to 12% of the height of the weak cationic resin layer.
Raw water having an ionic composition shown in Table 1 was passed through the resin tower at 60 liter / h to a cation break (
Strong type cationic resin layer: 2.6 liters (standard type),
Weak type cationic resin layer: 1.6 liters (standard type)
Regeneration level: 81.5 g-HCl / liter-strong resin,
[0019]
[Table 1]
[Table 2]
Table 3 shows the results of 40 cycles of water flow and regeneration under these conditions. The treatment water quality of the cation tower was slightly poor because the drug passing time was as short as 10 minutes, but even after 40 cycles, the amount of water collected was almost constant at around 800 liters, and the regeneration efficiency was good at about 93%.
[Table 3]
Example 2
The same conditions as in Example 1 except that Dowex HGR-W2 (effective diameter 0.50 mm) excluding a large particle size of 0.7 mm or more was used instead of Dowex HGR-W2 as a strong cationic resin. Water circulation and regeneration were repeated 40 cycles. The results are shown in Table 4.
The treatment water quality of the cation tower was better than that of Example 1 although the drug passing time was as short as 10 minutes. The amount of water collected was almost constant at around 830 liters, and the regeneration efficiency was good at almost 96%.
[0023]
[Table 4]
Comparative Example 1
Dowex HGR-W2, with a large particle size of 0.7 mm or more removed as a strong cationic resin, is packed in a resin tower having an inner diameter of 60 mm and a height of 2000 mm, excluding the intermediate partition, and a layer height of 1015 mm. Type cation resin Dowex MAC-3 was filled in H shape with a layer height of 625 mm. When 840 liters of raw water in Table 1 was passed through the resin tower and backwashed, the strong cation resin and the weak cation resin were completely mixed. 6.3 liters of 5% HCl was passed through the mixed resin in a downward flow to regenerate the resin, and then backwashed again, but the strong cation resin and weak cation resin were mixed and separated into two layers. I couldn't.
[0025]
【The invention's effect】
According to the present invention, the disadvantage of the conventional countercurrent regenerative ion exchange apparatus in which a strong and weak ion exchange resin is packed in one column, that is, (1) the quality of treated water by mixing strong and weak ion exchange resins. Deterioration and reduction of water sampling, (2) Restriction of combination of strong and weak ion exchange resins, (3) Deterioration of treated water quality due to interruption of water flow, (4) Complexity of equipment and regeneration operation all at once can be solved. As a result, it is possible to provide a simple and compact ion exchange apparatus and a regeneration method that can be completed easily and in a short time, and a good quality of treated water can be obtained inexpensively and stably.
[Brief description of the drawings]
FIG. 1 is a schematic view of an ion exchange column showing an example of an embodiment of the present invention.
[Explanation of symbols]
1: resin tower, 2: intermediate partition, 3: lower water collector, 4: upper water collector, 5: strong ion exchange resin, 6: free board, 7: inert resin, 8: weak ion exchange resin 9: Free board, 10: Inactive resin, 11: Raw water inflow valve, 12: Reclaimed drainage outflow valve, 13: Treated water outflow valve, 14: Backwash water inflow valve, 15: Regenerant inflow valve, 16: Washing valve,
Claims (3)
（ａ）下部集水装置からの高流速逆洗により強・弱型イオン交換樹脂の大部分を不活性樹脂層に押しつけ、通水時に蓄積した懸濁物質を不活性樹脂層を経由して上部集水装置から排出除去すると共に、強・弱型イオン交換樹脂の固定床を形成する工程、
（ｂ）高流速逆洗に引き続き、高流速逆洗より低速で且つ、上記（ａ）工程で形成された固定床を維持するに必要な流速で再生剤を下部集水装置から通薬する工程、
（ｃ）通薬に引き続き、通薬工程（ｂ）とほぼ同じ流速で下部集水装置から処理水を通水し、残留する再生剤を押出す押出工程、
（ｄ）押出終了後、通水を停止し、再生された樹脂を自由に落下させる沈整工程、
（ｅ）上部集水装置から下降流で通水して樹脂を洗浄する洗浄工程。3. A regeneration method for a countercurrent regeneration ion exchange apparatus according to claim 1 or 2, wherein the resin is regenerated by sequentially performing the following steps (a) to (e). Playback method.
(A) Most of the strong / weak ion exchange resin is pressed against the inert resin layer by backwashing at a high flow rate from the lower water collecting device, and the suspended matter accumulated during water flow passes through the inert resin layer. A process of forming a fixed bed of strong and weak ion exchange resin, while discharging and removing from the water collecting device,
(B) A step of feeding the regenerant from the lower water collecting device at a flow rate that is lower than the high flow rate backwash and that is necessary for maintaining the fixed bed formed in the step (a) following the high flow rate backwash. ,
(C) An extrusion process in which treated water is passed from the lower water collecting device at approximately the same flow rate as the drug delivery process (b) following the drug delivery, and the remaining regenerant is extruded.
(D) a settling process in which water flow is stopped after extrusion and the regenerated resin is freely dropped;
(E) A cleaning step of cleaning the resin by passing water downward from the upper water collecting device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30230895A JP3907012B2 (en) | 1995-10-27 | 1995-10-27 | Counter-current regenerative ion exchange apparatus and regeneration method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30230895A JP3907012B2 (en) | 1995-10-27 | 1995-10-27 | Counter-current regenerative ion exchange apparatus and regeneration method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09117676A JPH09117676A (en) | 1997-05-06 |
| JP3907012B2 true JP3907012B2 (en) | 2007-04-18 |
Family
ID=17907401
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30230895A Expired - Lifetime JP3907012B2 (en) | 1995-10-27 | 1995-10-27 | Counter-current regenerative ion exchange apparatus and regeneration method thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3907012B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108654585B (en) * | 2018-07-17 | 2023-05-16 | 南京大学 | Resin regeneration device and resin regeneration method |
| CN111056594A (en) * | 2019-12-26 | 2020-04-24 | 世源科技工程有限公司 | Fixed bed capable of supporting bed regeneration and regeneration process thereof |
| KR102415550B1 (en) * | 2021-11-19 | 2022-07-01 | 주식회사 에이이 | Method recovering useful metal in concentrated water according to seawater-desalination |
-
1995
- 1995-10-27 JP JP30230895A patent/JP3907012B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09117676A (en) | 1997-05-06 |
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