JP4593830B2

JP4593830B2 - Mixed-bed type sugar solution refining device, regenerating method of mixed-bed type sugar solution purifying device, and purification method

Info

Publication number: JP4593830B2
Application number: JP2001164216A
Authority: JP
Inventors: 友二浅川; 伸浅野
Original assignee: Organo Corp
Current assignee: Organo Corp
Priority date: 2001-05-31
Filing date: 2001-05-31
Publication date: 2010-12-08
Anticipated expiration: 2021-05-31
Also published as: JP2002355100A

Description

【０００１】
【発明の属する技術分野】
本発明は、糖液を脱塩脱色する混床式糖液精製装置、混床式糖液精製装置の再生方法および糖液の精製方法に関するものである。
【０００２】
【従来の技術】
糖液の精製は、原糖液を炭酸飽充、粒状活性炭濾過、骨炭濾過等の前処理を行った後、後処理としてイオン交換処理が行われている。後処理としてのイオン交換処理には、脱色を目的としたイオン交換処理と脱塩を目的としたイオン交換処理がある。
【０００３】
脱塩を目的としたイオン交換処理には、前処理された糖液を強塩基性アニオン交換樹脂の単床で処理した後、弱酸性カチオン交換樹脂の単床で処理して脱塩を行う二床式精製装置を用いるリバース処理と、前処理された糖液を強塩基性アニオン交換樹脂と弱酸性カチオン交換樹脂を混合した混床式精製装置で処理して脱塩する混床式処理がある。
【０００４】
リバース処理は工業的に広く採用されているが、処理純度が充分でないという問題点がある。一方、リバース処理に比べて、混床式処理はイオン交換樹脂の再生操作が煩雑であるものの、高純度の糖液が得られる点で、糖液の精製処理として優れた方法である。
【０００５】
混床式精製装置におけるイオン交換樹脂の再生方法としては、例えば特開平２−２９８３５８号公報、特開平１１−７６８４０号公報等に記載された方法が知られている。
【０００６】
図３は、上記特開平２−２９８３５８号公報の混床式精製装置の再生方法を説明するための模式断面図であり、塩基性アニオン交換樹脂と弱酸性カチオン交換樹脂が分離され、酸再生剤を一貫して通薬した後の状態を示すものである。なお、図３において３１は混床式精製装置であり、３５は再生剤を供給するためのディストリビュータであり、混床塔の下部にはイオン交換樹脂を支持するための支持床３７が設置されている。図３に示したように、従来の混床式糖液精製装置では、コレクタ３２は弱酸性カチオン交換樹脂に酸再生剤を通薬して遊離酸形とした弱酸性カチオン交換樹脂３４と強塩基性アニオン交換樹脂３３との分離境界面３６に設けられている。
【０００７】
特開平２−２９８３５８号公報に記載された再生方法は、混床塔で糖液処理を終了した後、糖液や食塩水等を利用し両樹脂の比重差により弱酸性カチオン交換樹脂を下層に、強塩基性アニオン交換樹脂を上層に分離し、上層の強塩基性アニオン交換樹脂および下層の弱酸性カチオン交換樹脂の双方に塩酸水溶液等の酸再生剤を一貫して通液し、強塩基性アニオン交換樹脂の回生と弱酸性カチオン交換樹脂の再生を同時に行った後、上層の強塩基性アニオン交換樹脂に水酸化ナトリウム水溶液等のアルカリ再生剤を通液し、同時に混床塔の下部から水を上向流で通水し、両樹脂の分離境界面に設けたコレクタより再生廃液を排出して、上層の強塩基性アニオン交換樹脂を再生した後、両樹脂を混合し混床を形成させる方法である。
【０００８】
また、特開平１１−７６８４０号公報に記載された方法は、弱酸性カチオン交換樹脂と強塩基性アニオン交換樹脂を上下二層に分離することと、上層の強塩基性アニオン交換樹脂および下層の弱酸性カチオン交換樹脂の双方に酸再生剤を一貫して通薬し強塩基性アニオン交換樹脂の回生と弱酸性カチオン交換樹脂の再生を、下層から酸再生剤を通薬して同時に行うことを特徴とするものである。
【０００９】
このような混床式の糖液精製装置では、糖液処理の過程において、弱酸性カチオン交換樹脂は、遊離酸形からＮａ形、Ｃａ形等の塩形へのイオン交換の進行に伴って次第に膨潤するが、酸再生処理によって遊離酸形となって収縮し、膨潤が解消される。そのため、混床式の糖液精製装置におけるコレクタの位置は、酸再生剤を両樹脂に一貫して通薬して弱酸性カチオン交換樹脂が遊離酸形となって収縮したときの強塩基性アニオン交換樹脂と弱酸性カチオン交換樹脂との分離境界面、すなわち、弱酸性カチオン交換樹脂が遊離酸形である場合の分離境界面にコレクタがくるように設定されている。
【００１０】
上記の再生方法は、再生処理毎に、強塩基性アニオン交換樹脂にも酸再生剤が通薬されるので、弱酸性カチオン交換樹脂の再生処理と同時に強塩基性アニオン交換樹脂が回生される利点がある。
【００１１】
また、従来の混床式精製装置では処理糖液にＮａがリークするが、このＮａリークを防ぐことを目的として、特開平１０−５７１００号公報には、混床式精製装置の再生においてコレクタの位置を両樹脂の分離境界面より上に設置する技術が開示されている。特開平１０−５７１００号公報に記載された糖液精製装置は、Ｎａのリークを防ぐ優れたものである。
【００１２】
【発明が解決しようとする課題】
しかしながら上記従来の混床式処理システムで処理サイクルを重ねてゆくと、徐々に処理液のｐＨが酸性側に振れることがあった（ｐＨ４．５〜６．０）。その原因は、弱酸性カチオン交換樹脂に比べ、強塩基性アニオン交換樹脂の劣化が早く進むため、強塩基性アニオン交換樹脂で酸性成分を捕捉しきれなくなるためである。処理糖液のｐＨが酸性側に振れると、ショ糖の分解が起こりやすくなるので、糖液の精製においては、処理糖液のｐＨが酸性側に振れることはできるだけ避けなければならない。
【００１３】
強塩基性アニオン交換樹脂の劣化による処理液のｐＨが酸性に振れることを防ぐためには、イオン交換樹脂を交換することで解決できるが、高価なイオン交換樹脂を交換することは精製コストの上昇につながるため、できるだけ交換頻度を減らすシステムが望まれている。
【００１４】
本発明が解決しようとする課題は、混床式の糖液精製装置において、処理サイクルを重ねてゆくと徐々に処理液のｐＨが酸性に振れることを防ぐことができる混床式糖液精製装置、混床式糖液精製装置の再生方法および糖液の精製方法を提供することにある。
【００１５】
【課題を解決するための手段】
本発明者らが鋭意研究を重ねた結果、混床式糖液精製装置において、再生剤廃液を排出するコレクタの位置を調節することにより上記課題を解決できることを見出し本発明を完成するに至った。
【００１６】
上記課題を解決するための第１の発明は、強塩基性アニオン交換樹脂と弱酸性カチオン交換樹脂を充填した混床式糖液精製装置であって、イオン交換樹脂の再生工程において、弱酸性カチオン交換樹脂が遊離酸形である時の上層の強塩基性アニオン交換樹脂と下層の弱酸性カチオン交換樹脂との分離境界面より下部に、再生廃液を排出するコレクタを設けたことを特徴とする混床式糖液精製装置に関するものである。
【００１７】
また上記課題を解決するための第２の発明は、強塩基性アニオン交換樹脂と弱酸性カチオン交換樹脂を充填した混床式糖液精製装置の再生方法であって、イオン交換樹脂の再生工程において、上層が強塩基性アニオン交換樹脂であり、下層が再生された遊離形弱酸性カチオン交換樹脂である分離されたイオン交換樹脂の上層の強塩基性アニオン交換樹脂にアルカリ再生剤を通薬する際に、上層の強塩基性アニオン交換樹脂と下層の遊離形弱酸性カチオン交換樹脂の分離境界面より下部に設けたコレクタによりアルカリ再生剤の再生廃液を排出することを特徴とする混床式糖液精製装置の再生方法に関するものである。
【００１８】
さらに上記課題を解決するための第３の発明は、強塩基性アニオン交換樹脂と弱酸性カチオン交換樹脂を充填した混床式糖液精製装置を用いて糖液を精製する方法において処理糖液のｐＨが低下した場合に、イオン交換樹脂の再生工程において、弱酸性カチオン交換樹脂が遊離酸形である時の上層の強塩基性アニオン交換樹脂と下層の弱酸性カチオン交換樹脂との分離境界面より下部に、再生廃液を排出するコレクタが位置するように、弱酸酸性カチオン交換樹脂を加えることを特徴とする糖液の精製方法に関するものである。
【００１９】
【発明の実施の形態】
本発明の特徴は、分離境界面の下部にコレクタを設けた混床式糖液精製装置を用いることにより処理糖液のｐＨが酸性になることを防ぐものである。
【００２０】
本発明において処理対象となる主な糖液とは、サトウキビやビートを原料とする原糖液に炭酸飽充、粒状活性炭濾過、骨炭濾過等の前処理を施したものである。
【００２１】
図１により本発明の混床式糖液精製装置を説明する。図１は、本発明の混床式糖液精製装置の再生工程において、上層の強塩基性アニオン交換樹脂と下層の再生された遊離酸形弱酸性カチオン交換樹脂に分離された状態を示す模式断面図である。再生処理にあたって、混床式糖液装置１内の混合樹脂は比重差を利用して上層の強塩基性アニオン交換樹脂３と下層の遊離酸形弱酸性カチオン交換樹脂４に分離され、分離境界面６を境に二層に分離されている。
【００２２】
図１に示したように、上層の強塩基性アニオン交換樹脂と下層の遊離酸形弱酸性カチオン交換樹脂との分離境界面６の下部に設置されたコレクタ２を有する混床式糖液精製装置１を用いることにより、強塩基性アニオン交換樹脂の再生剤であるアルカリ再生剤をディストリビュータ５より通薬すると、弱酸性カチオン交換樹脂４のうちコレクタ２より上方にある弱酸性カチオン交換樹脂に、水酸化ナトリウム水溶液等のアルカリ再生剤が接触する。
【００２３】
これにより、アルカリ再生剤と接触した弱酸性カチオン交換樹脂がＮａ形等の塩形となる。そのため再生後の糖液処理に際して、極微量のＮａが処理糖液にリークすることにより、強塩基性アニオン交換樹脂で捕捉できなかった酸性成分を中和し、処理糖液のｐＨが酸性に振れることを防止することができる。
【００２４】
本発明において用いられるイオン交換樹脂は、糖液精製のために使用される従来既知の強塩基性アニオン交換樹脂（例えばアンバーライト（登録商標、以下同様）IRA-402BL 、IRA-900 、XT-5007 、ダイヤイオン（登録商標、以下同様）PA312 、PA308 ）、弱酸性カチオン交換樹脂（例えばアンバーライトIRC-76、IRC-50、レバチット（登録商標、以下同様）CNP-80、ダイヤイオンWK11）のいずれも使用することができる。
【００２５】
なお本発明の混床式糖液精製装置を用いると処理糖液にＮａが微量リークするが、処理糖液に残存するＮａの量は１０^-6.0〜１０^-4.5ｍｏｌ／Ｌ（炭酸カルシウム換算で０．０５〜１．６ｍｇＣａＣＯ₃ ／Ｌ）であり、処理糖液の品質上、特に問題となることはない。
【００２６】
本発明において、コレクタ２の位置は強塩基性アニオン交換樹脂３と遊離酸形弱酸性カチオン交換樹脂４との分離境界面６より下方に設ける必要があるが、通常は分離境界面６より、下層の遊離酸形弱酸性カチオン交換樹脂の層高（ｈ_c ）の０．５〜１０％分下部に、好ましくは１〜５％分下部に設置すればよい。コレクタ２を下層の遊離酸形弱酸性カチオン交換樹脂の層高（ｈ_c ）の１０％分を超えて下方に設けると、コレクタ２の上方に存在する弱酸性カチオン交換樹脂が再生時にアルカリ再生剤と接触する量が多くなり、処理糖液のｐＨがアルカリ性となってしまう。また、コレクタ２を設ける位置が遊離酸形弱酸性カチオン交換樹脂の層高（ｈ_c ）の０．５％未満では、強塩基性アニオン交換樹脂３を再生する際に、アルカリ再生剤と接触する弱酸性カチオン交換樹脂の量が少なくなって、所期の目的を達成できない場合があるので好ましくない。
【００２７】
コレクタ２の設置位置を決める際の基準面となる分離境界面６とは、上述のごとく強塩基性アニオン交換樹脂３と遊離酸形の弱酸性カチオン交換樹脂４とに分離した時の両樹脂層が接する面を意味し、通常は混床式糖液精製装置の設計段階で定められる。また、分離境界面６からの下方への距離を決めるための基準となる弱酸性カチオン交換樹脂の層高（ｈ_c ）とは、強塩基性アニオン交換樹脂と弱酸性カチオン交換樹脂が完全に分離された場合のＨ形（基準形）の弱酸性カチオン交換樹脂の層高を意味する。
【００２８】
図２に本発明の混床式糖液精製装置を用いて、糖液の精製処理工程および再生工程を行う場合の一実施形態を示す。
【００２９】
図２（ａ）は、強塩基性アニオン交換樹脂と弱酸性カチオン交換樹脂との混合樹脂８が充填された混床式糖液精製装置１の上部から前処理された原料糖液を通液し、混床式糖液精製装置１の下部から、精製糖液を回収する工程を示すものである。
【００３０】
上記の精製処理工程を終了後、混床式糖液装置１内のイオン交換樹脂を再生するには、まず混合樹脂８を糖液や食塩水を利用した比重分離等の操作により、上層の強塩基性アニオン交換樹脂３と下層の弱酸性カチオン交換樹脂４とに分離する（図２（ｂ））。
【００３１】
弱酸性カチオン交換樹脂４は、前述のごとく糖液の処理過程において、イオン交換の進行により膨潤して、体積が５０〜１００％程度増加するため、糖液精製処理終了直後の強塩基性アニオン交換樹脂と弱酸性カチオン交換樹脂との分離境界面は、図２（ｂ）に示したようにコレクタ２の上部に存在する。
【００３２】
次いで、図２（ｃ）に示したように、混床式糖液精製装置１の上部に設置したディストリビュータ５により塩酸等の酸再生剤を通薬し、上層の強塩基性アニオン交換樹脂３と下層の弱酸性カチオン交換樹脂の双方に一貫通薬し、混床式糖液精製装置１の下部から排出する。酸再生剤の通薬により、下層の弱酸性カチオン交換樹脂が再生され遊離酸形となり体積が収縮する。
【００３３】
弱酸性カチオン交換樹脂が収縮した後においても、両イオン交換樹脂の分離境界面がコレクタ２の上方に位置するようになる。なお、酸再生剤の通薬により上層の強塩基性アニオン交換樹脂３に吸着された有機酸等の不純物が取り除かれて強塩基性アニオン交換樹脂３が回生される。
【００３４】
その後、強塩基性アニオン交換樹脂３を再生するが、強塩基性アニオン交換樹脂３の再生は、図２（ｄ）に示したように、ディストリビュータ５より水酸化ナトリウム水溶液等のアルカリ再生剤を通薬し、同時に水を混床式糖液精製装置１の下部から通水し、コレクタ２よりアルカリ再生剤と水を排出する。
【００３５】
先の図１に詳しく示したように、両イオン交換樹脂の分離境界面６の下部にコレクタ２が設置されているため、強塩基性アニオン交換樹脂３の再生時にコレクタ２より上部に存在する弱酸性カチオン交換樹脂にアルカリ再生剤が接触する。これにより弱酸性カチオン交換樹脂の一部がＮａ形等の塩形になる。従って、再生後の精製処理工程において、処理糖液にＮａが若干リークするので、処理糖液のｐＨが酸性に振れるのを防ぐことができる。
【００３６】
なお、上述の実施形態では、再生工程において分離操作終了後、強塩基性アニオン交換樹脂と弱酸酸性カチオン交換樹脂とに酸再生剤を一貫して通薬する再生方法について説明したが、本発明装置の再生方法はこれに限定されず、例えば分離操作を行う前の混合状態のイオン交換樹脂に酸再生剤を通液し、しかる後に分離操作を行ってもよいし、また、分離操作終了後、混床式糖液精製装置１の下部より酸再生剤を通薬するとともに再生廃液をコレクタ２から排出することによってまず弱酸酸性カチオン交換樹脂４のみを再生し、次いで、上部のディストリビュータ５によりアルカリ再生剤を通薬する再生廃液をコレクタ２から排出することによって強塩基性アニオン交換樹脂３を再生するようにしてもよい。
【００３７】
なお、コレクタが分離境界面に位置するように設定された従来の混床式糖液精製装置において、精製処理工程において処理糖液のｐＨが上昇するようになった場合でも、再生工程において、分離された強塩基性アニオン交換樹脂と遊離酸形弱酸性カチオン交換樹脂の分離境界面より下方にコレクタが位置するように弱酸性カチオン交換樹脂を追加してもよい。
【００３８】
【実施例】
以下実施例により本発明をさらに詳細に説明するが、本発明はこれらの実施例に限定されるものではない。
【００３９】
実施例１
強塩基性アニオン交換樹脂（商品名「アンバーライトＩＲＡ−４０２ＢＬ」、ロームアンドハース社製）３Ｌと弱酸性カチオン交換樹脂（商品名「アンバーライトＩＲＣ−７６」、ロームアンドハース社製）１．５Ｌを、図１に示したような混床式の糖液精製装置に充填した。この樹脂は長期にわたって実装置で使われた樹脂である（２００サイクル以上）。
【００４０】
実施例１の混床式糖液精製装置では、コレクタの位置を下層の弱酸性カチオン交換樹脂（Ｈ形）の層高の１％分分離境界面より下部に設置した。
【００４１】
原糖液の純度および糖液処理の処理条件を表１に示す。
【００４２】
【表１】

【００４３】
糖液処理後の再生は以下のように行った。まず、混合樹脂を飽和食塩水により分離し、糖液精製装置上部のディストリビュータより３．５％の塩酸を４．５Ｌ通薬し、糖液精製装置の下部より排出した。続いて、４．０％の水酸化ナトリウム水溶液６．０Ｌを上記ディストリビュータより通薬し、同時に水を糖液精製装置の下部から通水し、コレクタより排出した。更にこの後、糖液精製装置の上部および下部から洗浄水を通水し、洗浄水をコレクタから排出して再生処理を完了した。
【００４４】
比較例１
コレクタの位置を分離境界面に位置するように設置した図３に示したような従来の糖液精製装置を用いた他は、実施例１に準じて、糖液の精製処理および再生処理を行った。
【００４５】
比較例２
特開平１０−５７１００号公報に準じてコレクタの位置を上層の強塩基性アニオン交換樹脂（Ｃｌ形）の層高の５％分分離境界面より上部に設定した他は、実施例１に準じて、糖液の精製処理および再生処理を行った。
【００４６】
実施例２
比較例２の装置に、新品の弱酸性カチオン交換樹脂を加えた。新品の弱酸性カチオン交換樹脂は、コレクタの位置が下層の弱酸性カチオン交換樹脂（Ｈ形）の層高の１％分分離境界面の下になる量を加えた。すなわち３１８ｍｌの弱酸性カチオン交換樹脂を加えて、実施例１に準じて、糖液の精製処理および再生処理を行った。
【００４７】
実施例１，２および比較例１，２の混床式の糖液精製装置を用いて、糖液の精製処理を行ったときの、処理糖液のｐＨを測定した。その結果を表２に示す。
【００４８】
【表２】

【００４９】
表２に示した結果より明らかなとおり、実施例１，２の糖液精製装置は、従来の比較例１，２の糖液精製装置と比べて、処理糖液のｐＨが酸性に振れておらず、好ましいｐＨ範囲であることが認められた。
【００５０】
【発明の効果】
請求項１または２に記載の混床式糖液精製装置においては、コレクタの位置が分離境界面より下方であることにより、アルカリ再生剤による再生時に遊離酸形弱酸性カチオン交換樹脂の一部がＮａ塩形等の塩形になるため、処理糖液のｐＨが酸性側に振れるのを防ぐことができる。
【００５１】
請求項３または４に記載の混床式糖液精製装置の再生方法においては、コレクタの位置が分離境界面より下方であることにより、アルカリ再生剤による再生時に遊離酸形弱酸性カチオン交換樹脂の一部がＮａ塩形等の塩形になるため、処理糖液のｐＨが酸性側に振れるのを防ぐことができる。
【００５２】
請求項５または６に記載の糖液の精製方法においては、弱酸性カチオン交換樹脂を追加補充することによってコレクタの位置を分離境界面より下方とすることにより、アルカリ再生剤による再生時に遊離酸形弱酸性カチオン交換樹脂の一部がＮａ塩形等の塩形になるため、処理糖液のｐＨが酸性側に振れるのを防ぐことができる。
【図面の簡単な説明】
【図１】本発明の混床式糖液精製装置の、再生工程における強塩基性アニオン交換樹脂と弱酸性カチオン交換樹脂が分離された状態を示す模式断面図。
【図２】（ａ）〜（ｄ）は、本発明の混床式糖液精製装置の再生方法を説明するための模式断面図。
【図３】従来の混床式糖液精製装置の、再生工程における強塩基性アニオン交換樹脂と弱酸性カチオン交換樹脂が分離された状態を示す模式断面図。
【符号の説明】
１混床式糖液精製装置
２コレクタ
３強塩基性アニオン交換樹脂
４弱酸性カチオン交換樹脂
５ディストリビュータ
６分離境界面
７支持床[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mixed bed type sugar solution refining device for desalting and decolorizing a sugar solution, a regeneration method for the mixed bed type sugar solution purifying device, and a method for purifying a sugar solution.
[0002]
[Prior art]
The sugar solution is refined by subjecting the raw sugar solution to pretreatment such as carbonation saturation, granular activated carbon filtration, bone charcoal filtration, etc., and then ion exchange treatment as post-treatment. The ion exchange treatment as a post-treatment includes an ion exchange treatment for decolorization and an ion exchange treatment for desalting.
[0003]
In the ion exchange treatment for desalting, the pretreated sugar solution is treated with a single bed of a strongly basic anion exchange resin and then treated with a single bed of a weakly acidic cation exchange resin. There is a reverse treatment using a bed type purification device and a mixed bed type treatment in which the pretreated sugar solution is treated with a mixed bed type purification device in which a strongly basic anion exchange resin and a weakly acidic cation exchange resin are mixed and desalted. .
[0004]
Reverse processing is widely used industrially, but has a problem that the processing purity is not sufficient. On the other hand, compared with the reverse treatment, the mixed bed treatment is an excellent method for refining a sugar solution in that a high-purity sugar solution can be obtained although the regeneration operation of the ion exchange resin is complicated.
[0005]
As a method for regenerating the ion exchange resin in the mixed bed purification apparatus, for example, methods described in JP-A-2-298358 and JP-A-11-76840 are known.
[0006]
FIG. 3 is a schematic cross-sectional view for explaining the regeneration method of the mixed bed type purification apparatus described in JP-A-2-298358, in which a basic anion exchange resin and a weakly acidic cation exchange resin are separated, and an acid regenerant. This shows the state after consistent medication. In FIG. 3, 31 is a mixed bed purification apparatus, 35 is a distributor for supplying a regenerant, and a support bed 37 for supporting an ion exchange resin is installed at the lower part of the mixed bed tower. Yes. As shown in FIG. 3, in the conventional mixed-bed type sugar liquid refining apparatus, the collector 32 has a weak acid cation exchange resin 34 and a strong base formed into a free acid form by passing an acid regenerant through a weak acid cation exchange resin. It is provided on the separation interface 36 with the anionic exchange resin 33.
[0007]
In the regeneration method described in JP-A-2-298358, after the sugar solution treatment is completed in the mixed bed tower, a weakly acidic cation exchange resin is used as a lower layer due to a difference in specific gravity between the two resins using a sugar solution or saline. The strong basic anion exchange resin is separated into the upper layer, and an acid regenerant such as aqueous hydrochloric acid solution is consistently passed through both the upper strong anion exchange resin and the weak acidic cation exchange resin in the lower layer. After regeneration of the anion exchange resin and regeneration of the weakly acidic cation exchange resin at the same time, an alkaline regenerant such as an aqueous sodium hydroxide solution is passed through the upper strong base anion exchange resin, and water is simultaneously added from the bottom of the mixed bed tower. Water is drained from the collector provided at the separation boundary surface of both resins, and the strong base anion exchange resin in the upper layer is regenerated, and then both resins are mixed to form a mixed bed. Is the method.
[0008]
In addition, the method described in JP-A-11-76840 discloses that a weakly acidic cation exchange resin and a strongly basic anion exchange resin are separated into two upper and lower layers, a strong basic anion exchange resin in the upper layer, and a weaker in the lower layer. The acid regenerator is consistently applied to both acidic cation exchange resins, and regeneration of strong basic anion exchange resins and regeneration of weak acid cation exchange resins are performed simultaneously by applying acid regenerant from the lower layer. It is what.
[0009]
In such a mixed-bed type sugar solution refining apparatus, in the process of sugar solution treatment, the weakly acidic cation exchange resin is gradually added with the progress of ion exchange from the free acid form to the salt form such as Na form and Ca form. Although it swells, it is shrunk into a free acid form by the acid regeneration treatment, and the swelling is eliminated. Therefore, the position of the collector in the mixed-bed type sugar liquid refining apparatus is a strongly basic anion when the acid regenerant is consistently passed through both resins and the weak acid cation exchange resin contracts into the free acid form. The collector is set so that the collector comes to the separation interface between the exchange resin and the weak acid cation exchange resin, that is, the separation interface when the weak acid cation exchange resin is in the free acid form.
[0010]
In the above regeneration method, an acid regenerant is also passed to the strongly basic anion exchange resin for each regeneration treatment, so that the strong base anion exchange resin is regenerated at the same time as the regeneration treatment of the weak acid cation exchange resin. There is.
[0011]
Further, in the conventional mixed bed purification apparatus, Na leaks into the treated sugar solution. For the purpose of preventing this Na leak, Japanese Patent Application Laid-Open No. 10-57100 discloses a collector in the regeneration of the mixed bed purification apparatus. A technique for setting the position above the separation boundary surface of both resins is disclosed. The sugar liquid purification apparatus described in JP-A-10-57100 is excellent in preventing Na leakage.
[0012]
[Problems to be solved by the invention]
However, when the processing cycle is repeated in the conventional mixed bed processing system, the pH of the processing solution may gradually shift to the acidic side (pH 4.5 to 6.0). The reason is that the strong base anion exchange resin deteriorates faster than the weak acid cation exchange resin, and the strong basic anion exchange resin cannot capture the acidic component. When the pH of the processed sugar solution is shifted to the acidic side, sucrose is likely to be decomposed. Therefore, in the purification of the sugar solution, it is necessary to avoid the pH of the processed sugar solution to be shifted to the acidic side as much as possible.
[0013]
In order to prevent the pH of the treatment solution from shifting to acidic due to deterioration of the strongly basic anion exchange resin, it can be solved by replacing the ion exchange resin, but replacing the expensive ion exchange resin increases the purification cost. Therefore, a system that reduces the frequency of replacement as much as possible is desired.
[0014]
The problem to be solved by the present invention is a mixed bed type sugar liquid refining apparatus that can prevent the pH of the processing liquid from gradually shifting to acidic as the processing cycle is repeated. Another object of the present invention is to provide a method for regenerating a mixed bed sugar solution purifier and a method for purifying a sugar solution.
[0015]
[Means for Solving the Problems]
As a result of intensive studies by the present inventors, it has been found that the above-mentioned problems can be solved by adjusting the position of the collector that discharges the regenerant waste liquid in the mixed-bed type sugar liquid refining apparatus, and the present invention has been completed. .
[0016]
A first invention for solving the above-mentioned problem is a mixed bed type sugar liquid purification apparatus filled with a strongly basic anion exchange resin and a weakly acidic cation exchange resin. When the exchange resin is in the free acid form, the mixing is characterized in that a collector for discharging the regenerated waste liquid is provided below the separation boundary surface between the strong base anion exchange resin in the upper layer and the weak acid cation exchange resin in the lower layer. The present invention relates to a bed type sugar liquid purification apparatus.
[0017]
A second invention for solving the above-mentioned problems is a method for regenerating a mixed-bed sugar solution purifier filled with a strongly basic anion exchange resin and a weakly acidic cation exchange resin, in the regeneration process of the ion exchange resin. When an alkaline regenerator is applied to the strongly basic anion exchange resin in the upper layer of the separated ion exchange resin, the upper layer is a strongly basic anion exchange resin and the lower layer is a regenerated free weak acid cation exchange resin. In addition, a mixed bed type sugar solution is characterized in that the regeneration waste liquid of the alkaline regenerant is discharged by a collector provided below the separation boundary surface of the strong base anion exchange resin in the upper layer and the free weak acid cation exchange resin in the lower layer. The present invention relates to a regeneration method for a purification apparatus.
[0018]
Furthermore, a third invention for solving the above-mentioned problem is a method for purifying a sugar solution using a mixed bed sugar solution purifier filled with a strongly basic anion exchange resin and a weakly acidic cation exchange resin. When the pH is lowered, in the regeneration process of the ion exchange resin, when the weak acid cation exchange resin is in the free acid form, from the separation boundary surface between the upper strong base anion exchange resin and the lower weak acid cation exchange resin. The present invention relates to a method for purifying a sugar solution, characterized in that a weak acid acidic cation exchange resin is added so that a collector for discharging a recycled waste liquid is located at the bottom.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
The feature of the present invention is to prevent the pH of the treated sugar solution from becoming acidic by using a mixed bed type sugar solution refining device provided with a collector below the separation boundary surface.
[0020]
The main sugar solution to be treated in the present invention is obtained by subjecting a raw sugar solution made from sugarcane or beet to a pretreatment such as carbonation saturation, granular activated carbon filtration, and bone charcoal filtration.
[0021]
The mixed bed type sugar solution purifying apparatus of the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view showing a state where the upper layer strongly basic anion exchange resin and the lower layer regenerated free acid form weakly acidic cation exchange resin are separated in the regeneration step of the mixed bed type sugar liquid purification apparatus of the present invention. FIG. In the regeneration process, the mixed resin in the mixed bed type sugar solution apparatus 1 is separated into an upper strong base anion exchange resin 3 and a lower free acid form weakly acidic cation exchange resin 4 by utilizing the specific gravity difference, and the separation boundary surface It is separated into two layers with 6 as a boundary.
[0022]
As shown in FIG. 1, a mixed-bed type sugar solution refining apparatus having a collector 2 installed at the lower part of a separation interface 6 between a strong basic anion exchange resin in the upper layer and a weak acid cation exchange resin in the lower acid form. 1, when an alkaline regenerant, which is a regenerant of a strongly basic anion exchange resin, is passed from the distributor 5, water in the weak acid cation exchange resin 4 above the collector 2 is converted into water. An alkali regenerating agent such as an aqueous sodium oxide solution comes into contact.
[0023]
Thereby, the weakly acidic cation exchange resin which contacted the alkali regeneration agent becomes a salt form such as Na form. Therefore, when processing the sugar solution after regeneration, a very small amount of Na leaks into the processed sugar solution, neutralizing acidic components that could not be captured by the strongly basic anion exchange resin, and the pH of the processed sugar solution swings acidic. This can be prevented.
[0024]
The ion exchange resin used in the present invention is a conventionally known strongly basic anion exchange resin (for example, Amberlite (registered trademark, the same applies hereinafter) IRA-402BL, IRA-900, XT-5007 used for sugar solution purification. , Diaion (registered trademark, same as below) PA312, PA308), weakly acidic cation exchange resin (for example, Amberlite IRC-76, IRC-50, Levacit (registered trademark, same as below) CNP-80, Diaion WK11) Can also be used.
[0025]
When the mixed-bed type sugar solution purification apparatus of the present invention is used, a slight amount of Na leaks into the treated sugar solution, but the amount of Na remaining in the treated sugar solution is 10 ^−6.0 to 10 ^−4.5 mol / L (calculated in terms of calcium carbonate). 0.05 to 1.6 mg CaCO ₃ / L), and there is no particular problem on the quality of the treated sugar solution.
[0026]
In the present invention, the collector 2 needs to be provided below the separation boundary surface 6 between the strongly basic anion exchange resin 3 and the free acid form weakly acidic cation exchange resin 4. The free acid form weakly acidic cation exchange resin may be installed at a lower portion of 0.5 to 10% of the layer height (h _c ), preferably at a lower portion of 1 to 5%. When the collector 2 is provided below 10% of the layer height (h _c ) of the free acid form weakly acidic cation exchange resin in the lower layer, the weakly acidic cation exchange resin existing above the collector 2 becomes an alkali regenerant during regeneration. As a result, the amount of the sugar solution to be treated becomes alkaline. Further, when the position where the collector 2 is provided is less than 0.5% of the layer height (h _c ) of the free acid form weakly acidic cation exchange resin, it contacts the alkali regenerator when regenerating the strongly basic anion exchange resin 3. This is not preferable because the amount of the weakly acidic cation exchange resin decreases and the intended purpose may not be achieved.
[0027]
The separation boundary surface 6 serving as a reference surface for determining the installation position of the collector 2 is the two resin layers when separated into the strongly basic anion exchange resin 3 and the free acid weakly acidic cation exchange resin 4 as described above. Is usually determined at the design stage of the mixed-bed type sugar solution refining apparatus. Further, the layer height (h _c ) of the weakly acidic cation exchange resin, which serves as a reference for determining the downward distance from the separation boundary surface 6, is that the strongly basic anion exchange resin and the weakly acidic cation exchange resin are completely separated. It means the layer height of the weakly acidic cation exchange resin of the H form (reference form) when it is made.
[0028]
FIG. 2 shows an embodiment in the case where a sugar solution purification treatment step and a regeneration step are performed using the mixed bed type sugar solution purification apparatus of the present invention.
[0029]
FIG. 2 (a) shows that a pretreated raw sugar solution is passed from the upper part of the mixed bed type sugar solution refining apparatus 1 filled with a mixed resin 8 of a strongly basic anion exchange resin and a weak acid cation exchange resin. The process of recovering a purified sugar solution from the lower part of the mixed bed type sugar solution refining apparatus 1 is shown.
[0030]
In order to regenerate the ion exchange resin in the mixed bed type sugar solution apparatus 1 after the above purification process step, first, the mixed resin 8 is subjected to an operation such as specific gravity separation using a sugar solution or a saline solution to strengthen the upper layer. Separated into a basic anion exchange resin 3 and a weakly acidic cation exchange resin 4 in the lower layer (FIG. 2B).
[0031]
As described above, the weakly acidic cation exchange resin 4 swells with the progress of ion exchange in the process of sugar solution and increases in volume by about 50 to 100%. The separation boundary surface between the resin and the weakly acidic cation exchange resin exists at the upper part of the collector 2 as shown in FIG.
[0032]
Next, as shown in FIG. 2 (c), an acid regenerant such as hydrochloric acid is passed through a distributor 5 installed at the upper part of the mixed bed type sugar liquid refining apparatus 1, and the upper layer strongly basic anion exchange resin 3 and One penetrating agent is applied to both of the lower acidic cation exchange resins in the lower layer, and discharged from the lower part of the mixed-bed sugar solution purifier 1. By passing the acid regenerating agent, the underlying weakly acidic cation exchange resin is regenerated to become a free acid form and the volume shrinks.
[0033]
Even after the weakly acidic cation exchange resin contracts, the separation boundary surface between the two ion exchange resins is located above the collector 2. In addition, impurities such as an organic acid adsorbed on the strong basic anion exchange resin 3 in the upper layer are removed by passing the acid regenerating agent, and the strong basic anion exchange resin 3 is regenerated.
[0034]
Thereafter, the strong base anion exchange resin 3 is regenerated. As shown in FIG. 2D, the strong base anion exchange resin 3 is regenerated by passing an alkali regenerant such as an aqueous sodium hydroxide solution from the distributor 5. At the same time, water is passed from the lower part of the mixed bed type sugar liquid refining apparatus 1, and the alkali regenerant and water are discharged from the collector 2.
[0035]
As shown in detail in FIG. 1 above, since the collector 2 is installed at the lower part of the separation boundary surface 6 of both ion exchange resins, the weakly existing upper part of the collector 2 at the time of regeneration of the strongly basic anion exchange resin 3. An alkaline regenerant contacts the acidic cation exchange resin. As a result, a part of the weakly acidic cation exchange resin becomes a salt form such as Na form. Therefore, in the purification treatment step after regeneration, Na slightly leaks into the treated sugar solution, so that the pH of the treated sugar solution can be prevented from being acidic.
[0036]
In the above-described embodiment, the regeneration method in which the acid regenerant is consistently passed through the strong base anion exchange resin and the weak acid acidic cation exchange resin after completion of the separation operation in the regeneration step has been described. The regeneration method is not limited to this. For example, the acid regenerant may be passed through the ion exchange resin in a mixed state before the separation operation, and then the separation operation may be performed. First, only the weak acid acidic cation exchange resin 4 is regenerated by pouring the acid regenerant from the lower part of the mixed-bed sugar refining apparatus 1 and discharging the regenerated waste liquid from the collector 2, and then alkali regeneration by the upper distributor 5. The strongly basic anion exchange resin 3 may be regenerated by discharging from the collector 2 the regenerated waste liquid that passes the agent.
[0037]
In the conventional mixed-bed type sugar solution refining apparatus set so that the collector is positioned at the separation boundary surface, even if the pH of the treated sugar solution rises in the purification treatment step, the separation is performed in the regeneration step. The weak acid cation exchange resin may be added so that the collector is located below the separation boundary surface between the strong basic anion exchange resin and the free acid form weak acid cation exchange resin.
[0038]
【Example】
The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples.
[0039]
Example 1
3 L of strong basic anion exchange resin (trade name “Amberlite IRA-402BL”, manufactured by Rohm and Haas) and 1.5 L of weak acid cation exchange resin (trade name “Amberlite IRC-76”, manufactured by Rohm and Haas) Was packed in a mixed-bed type sugar solution refining apparatus as shown in FIG. This resin has been used in actual equipment for a long time (more than 200 cycles).
[0040]
In the mixed bed type sugar solution refining apparatus of Example 1, the collector was placed below the separation boundary surface by 1% of the layer height of the weakly acidic cation exchange resin (H type) in the lower layer.
[0041]
Table 1 shows the purity of the raw sugar solution and the treatment conditions of the sugar solution treatment.
[0042]
[Table 1]

[0043]
The regeneration after the sugar solution treatment was performed as follows. First, the mixed resin was separated with a saturated saline solution, 4.5 L of 3.5% hydrochloric acid was passed through a distributor at the top of the sugar liquid purification apparatus, and discharged from the bottom of the sugar liquid purification apparatus. Subsequently, 6.0 L of 4.0% sodium hydroxide aqueous solution was passed through the distributor, and at the same time, water was passed through the lower part of the sugar liquid purifier and discharged from the collector. Further, after that, washing water was passed from the upper part and the lower part of the sugar liquid purifier, and the washing water was discharged from the collector to complete the regeneration treatment.
[0044]
Comparative Example 1
A sugar solution purification process and a regeneration process were performed in the same manner as in Example 1 except that the conventional sugar solution purification apparatus as shown in FIG. 3 installed so that the collector was positioned at the separation boundary surface was used. It was.
[0045]
Comparative Example 2
According to Japanese Patent Laid-Open No. 10-57100, except that the collector position is set above the separation boundary surface by 5% of the layer height of the strong base anion exchange resin (Cl type) in the upper layer, according to Example 1. The sugar solution was purified and regenerated.
[0046]
Example 2
A new weakly acidic cation exchange resin was added to the apparatus of Comparative Example 2. A new weakly acidic cation exchange resin was added in such an amount that the collector position was 1% below the separation boundary surface of the layer height of the lower weakly acidic cation exchange resin (H type). That is, 318 ml of weakly acidic cation exchange resin was added, and the sugar solution was purified and regenerated according to Example 1.
[0047]
Using the mixed bed type sugar solution refining apparatus of Examples 1 and 2 and Comparative Examples 1 and 2, the pH of the treated sugar solution was measured when the sugar solution was purified. The results are shown in Table 2.
[0048]
[Table 2]

[0049]
As is clear from the results shown in Table 2, the sugar solution refining devices of Examples 1 and 2 were more acidic than the conventional sugar solution refining devices of Comparative Examples 1 and 2. The preferred pH range was observed.
[0050]
【The invention's effect】
In the mixed-bed type sugar liquid refining device according to claim 1 or 2, a part of the free acid form weakly acidic cation exchange resin is formed at the time of regeneration with an alkali regenerant because the collector is located below the separation boundary surface. Since it becomes a salt form such as a Na salt form, the pH of the treated sugar solution can be prevented from shifting to the acidic side.
[0051]
In the regeneration method of the mixed bed type sugar liquid refining device according to claim 3 or 4, the position of the collector is below the separation boundary surface, so that the free acid form weakly acidic cation exchange resin of Since a part is in a salt form such as a Na salt form, the pH of the treated sugar solution can be prevented from shifting to the acidic side.
[0052]
In the purification method of the sugar solution according to

claim

5 or 6, the free acid form is obtained at the time of regeneration with an alkali regenerating agent by additionally replenishing a weakly acidic cation exchange resin so that the collector is positioned below the separation boundary surface. Since a part of the weakly acidic cation exchange resin is in a salt form such as a Na salt form, the pH of the treated sugar solution can be prevented from shifting to the acidic side.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a state where a strongly basic anion exchange resin and a weakly acidic cation exchange resin are separated in a regeneration step of the mixed bed type sugar liquid purification apparatus of the present invention.
FIGS. 2A to 2D are schematic cross-sectional views for explaining a regeneration method of the mixed bed type sugar liquid purification apparatus of the present invention.
FIG. 3 is a schematic cross-sectional view showing a state in which a strongly basic anion exchange resin and a weakly acidic cation exchange resin are separated in a regeneration step of a conventional mixed bed type sugar liquid purification apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Mixed bed type sugar liquid refiner 2 Collector 3 Strongly basic anion exchange resin 4 Weakly acidic cation exchange resin 5 Distributor 6 Separation interface 7 Support bed

Claims

This is a mixed-bed type sugar solution refining device packed with a strongly basic anion exchange resin and a weakly acidic cation exchange resin. In the regeneration process of the ion exchange resin, when the weakly acidic cation exchange resin is in the free acid form, A mixed-bed type sugar liquid refining apparatus, characterized in that a collector for discharging a regenerated waste liquid is provided below a separation boundary surface between a basic anion exchange resin and a lower weak acid cation exchange resin.

0.5 to 10% below the layer height of the free acid form weakly acidic cation exchange resin from the separation interface between the strong base anion exchange resin in the upper layer and the free acid form weakly acidic cation exchange resin in the lower layer The mixed bed type sugar solution refining device according to claim 1, wherein the device is provided in

A method for regenerating a mixed bed type sugar solution refining apparatus filled with a strongly basic anion exchange resin and a weakly acidic cation exchange resin, wherein the upper layer is a strongly basic anion exchange resin and the lower layer is in a regeneration step of the ion exchange resin. Release of the upper strong base anion exchange resin and the lower layer when an alkaline regenerant is passed through the upper strong anion exchange resin of the separated ion exchange resin, which is a regenerated free weakly acidic cation exchange resin. A regeneration method for a mixed bed type sugar solution refining apparatus, characterized in that a waste solution for regeneration of an alkaline regenerant is discharged by a collector provided below a separation boundary surface of a weakly acidic cation exchange resin.

0.5 to 10% below the layer height of the free acid form weakly acidic cation exchange resin from the separation interface between the strong base anion exchange resin in the upper layer and the free acid form weakly acidic cation exchange resin in the lower layer The method for regenerating a mixed bed type sugar solution refining device according to claim 3, wherein the method is installed.

In the process of purifying sugar solution using a mixed bed type sugar solution refining device filled with strong basic anion exchange resin and weak acid cation exchange resin, when the pH of the treated sugar solution is lowered, in the regeneration process of ion exchange resin When the weak acid cation exchange resin is in the free acid form, the collector for discharging the regenerated waste liquid is located below the separation boundary surface between the strong base anion exchange resin in the upper layer and the weak acid cation exchange resin in the lower layer. A method for purifying a sugar solution, comprising adding a weak acid acidic cation exchange resin.

The collector position is 0.5 to 10% below the layer height of the free acid type weakly acidic cation exchange resin from the separation interface between the strong base anion exchange resin in the upper layer and the free acid type weakly acidic cation exchange resin in the lower layer. 6. The method for purifying a sugar solution according to claim 5, wherein a weakly acidic cation exchange resin is added so that