JP3681153B2

JP3681153B2 - Freeze separator

Info

Publication number: JP3681153B2
Application number: JP22445999A
Authority: JP
Inventors: 博義池田; 京二牧野; 信行松本; 泰男井口; 尚紀黒田; 弘孝寺井
Original assignee: Shin Nippon Air Technologies Co Ltd
Current assignee: Shin Nippon Air Technologies Co Ltd
Priority date: 1999-08-06
Filing date: 1999-08-06
Publication date: 2005-08-10
Anticipated expiration: 2019-08-06
Also published as: JP2001047034A

Description

【０００１】
【発明の属する技術分野】
本発明は、凍結分離装置に関する。
【０００２】
【従来の技術】
例えば図９に示すような、蒸気ボイラ１０２で発生させた蒸気を蒸気タービン１０３に供給し、蒸気タービン１０３を回転駆動させ、その回転駆動力を発電機１０４に伝えて発電を行うとともに、蒸気タービン１０３で使用した蒸気を復水器１０６へ供給し、ここで復水冷却塔１０５から送給された冷媒により冷却して復水させ、復水した水は、還水槽１０７を経て再び蒸気ボイラ１０２の蒸気発生に使用する、蒸気タービンによる発電システム１００では、蒸気ボイラ１０２や冷却塔１０５からブロー水がそれぞれ排出される。
【０００３】
従来、かかるブロー水等の廃水は、廃水処理専門業者に廃水処理を委託したり等していた。
【０００４】
【発明が解決しようとする課題】
しかし、廃水処理専門業者に廃水処理を委託する場合、廃水処理費が嵩むことが問題であった。
【０００５】
そこで、本発明の主たる課題は、廃水処理費のコストダウンを図ることにある。
【０００６】
【課題を解決するための手段】
上記課題を解決した本発明は、蓄熱槽内に製氷用冷媒が通る冷却コイルを設け、その冷却コイルの上方に散水器を設け、その冷却コイルの下方に貯水部を設け、前記貯水部の貯留水面を前記冷却コイルの下方に離間させて維持するように構成した、流下液膜式氷蓄熱装置と、
廃水供給源からの廃水を収集し貯留する廃水槽と、再利用水槽とを備え、
凍結分離運転時に、前記廃水槽に貯留されている廃水を当該廃水槽と前記流下液膜式氷蓄熱装置との間で連続的に循環させ、その循環廃水を前記流下液膜式氷蓄熱装置における前記散水器から散布し、その散布水を前記冷却コイルの表面または冷却コイルに付着した氷の表面を液膜状をなして巡らせながら流下させ、その流下過程で、流下廃水のうち実質的に純水分の一部のみを前記冷却コイルの表面または冷却コイルに付着した氷の表面に着氷させる一方、残部の濃縮分を当該着氷部位を通り流下する流下廃水に取り込ませて洗い流し、前記貯水部に到達した廃水は前記廃水槽に返送するように構成し、
凍結分離運転を終えた後に、前記廃水槽に残留している濃縮廃水を排出するように構成し、かつ、
再利用水製造運転時に、前記廃水槽から散水器への廃水供給ならびに前記貯水部から前記廃水槽への廃水返送を行わずに、前記冷却コイルに蓄えた氷を解氷してその解氷水を前記再利用水槽に供給するように構成したことを特徴とする、凍結分離装置である。
【０００７】
本発明において、前記流下液膜式氷蓄熱装置は複数の蓄熱槽を備えるとともに、少なくとも１つの蓄熱槽を使用して前記凍結分離運転を行うとともに、これと併行して残りの蓄熱槽の少なくとも１つを使用して前記再利用水製造運転を行うように構成するのは好ましい。
【０００８】
また、前記廃水槽を少なくとも２つ備えるとともに、それら廃水槽に対して前記廃水供給源からの廃水を選択的に供給するように構成し、
前記凍結分離運転および再利用水製造運転を交互に行うように構成し、
各凍結分離運転の間において前記廃水を収集する廃水槽を前記濃縮廃水を排出した廃水槽に切り替えるとともに、各凍結分離運転時においては廃水収集を行っていない廃水槽の貯留廃水を前記蓄熱槽に供給するように構成するのも好ましい。
【０００９】
また、前記廃水槽を少なくとも２つ備えるとともに、それら廃水槽に対して前記廃水供給源からの廃水を選択的に供給するように構成し、
他方、前記流下液膜式氷蓄熱装置は複数の蓄熱槽を備えるとともに、少なくとも１つの蓄熱槽を使用して前記凍結分離運転を行うとともに、これと併行して残りの蓄熱槽の少なくとも１つを使用して前記再利用水製造運転を行うように構成し、さらに、
前記廃水供給源からの廃水を、いずれか一方の廃水槽にのみ収集して貯留するとともに、他方の廃水槽に収集されている貯留廃水を凍結分離運転中の蓄熱槽に対し供給して氷として蓄えさせ、
前記一方の廃水槽の貯留量が所定量となったならば、前記廃水供給源からの廃水を、前記一方の廃水槽へ収集するのを止めて他方の廃水槽へ収集するように切り替えるとともに、前記一方の廃水槽の貯留廃水を凍結分離運転中の蓄熱槽に対し供給して氷として蓄えさせるように構成するのも好ましい。
【００１０】
＜作用＞
本発明装置は、廃水を氷蓄熱装置の凍結分離作用により清水と濃縮廃水とに分離するとともに、氷蓄熱装置に蓄えた氷を解氷して再利用可能な清水を得ることで、廃水処理コストを低下させることができるとともに、大半の水を再利用することができるものである。
【００１１】
特に冷却コイルへの着氷に際しては、流下廃水の純水分の一部のみが氷となって冷却コイル表面またはコイル付着氷表面に付着し、結果的に残部は濃縮された廃水（濃縮分）になり、凍結濃縮による分離がなされる。そしてこの残部濃縮分は、廃水の連続循環によって順次当該着氷部位を通り流下する廃水に順次取込まれ、洗い流される。したがって、濃縮分に含まれる不純物が一ヶ所に高濃度で留まりにくくなるため、製造した氷に不純物が取り込まれにくく、また着氷効率も高い（着氷し易い）。そしてその結果、廃水の９０％以上を純粋な氷として蓄えることができる。これに対して、冷却コイルを貯留水に浸漬した状態で製氷を行う、いわゆる浸管式氷蓄熱装置によると、５０％程度までしか純粋な氷にすることができない。一方、貯水部に到達した流下廃水は、冷却コイルに着氷した純水分だけ濃縮されており、これが廃水槽に返送されて貯留廃水と混合された後、当該混合廃水が再度流下液膜式氷蓄熱装置の散水器へと連続的に循環される。したがって、循環廃水は凍結濃縮作用により経時的に濃縮されていく。
【００１２】
また、流下液膜式氷蓄熱装置は解氷効率も高く、氷がなくなるまでは解氷冷水の温度が実質的に上昇しないので、その解氷用冷水を、空調用冷媒等の他の設備における冷媒として好適に利用できる利点もある。
【００１３】
【発明の実施の形態】
以下、本発明の実施の形態について添付図面を参照しつつ詳説する。
＜基本形態＞
図１は、本発明を適用した凍結分離装置例１を示しており、この凍結分離装置１は、冷凍機４Ｆからの製氷用冷媒が流通する複数の冷却コイル４Ｃを蓄熱槽４Ｔ内に設け、各冷却コイル４Ｃの上方に対応して複数の散水器４Ｓを設け、冷却コイル４Ｃの下方に貯水部４Ｗを設け、貯水部４Ｗの貯留水面を冷却コイル４Ｃの下方に離間して維持するように構成した流下液膜式氷蓄熱装置４（図示しないが、流下液膜式氷蓄熱装置４において貯留水面上方でかつ冷却コイル４Ｃの下方に解氷時に冷却コイル４Ｃから剥離して落下した氷を受け止める網状体を設けることができる）と、廃水供給源から供給される廃水を収集貯留する廃水槽２と、製造した再利用水を貯留する再利用水槽３とを備えている。
【００１４】
廃水槽２は廃水供給路２Ａを介して流下液膜式氷蓄熱装置４の散水器４Ｓと接続されており、その廃水供給路２Ａには廃水供給ポンプ２Ｂおよび廃水供給バルブ２Ｃがそれぞれ配設されている。一方、蓄熱槽４Ｔの貯水部４Ｗは、送水ポンプ４Ｐおよび廃水返送路２Ｄを介して廃水槽２に、ならびに送水ポンプ４Ｐおよび再利用水供給路３Ｄを介して再利用水槽３にそれぞれ接続されており、廃水返送路２Ｄには廃水返送バルブ２Ｅが、ならびに再利用水供給路３Ｄには再利用水供給バルブ３Ｅがそれぞれ配設されている。また、廃水槽２内には排出路２Ｆが連通しており、この排出路２Ｆに排出バルブ２Ｇが配設されている。
【００１５】
他方図示例では、再利用水槽３が流下液膜式氷蓄熱装置４の散水器４Ｓと接続されており、その再利用水循環路３Ａには再利用水循環ポンプ３Ｂおよび再利用水循環バルブ３Ｃがこの順に配設されており、また再利用水循環路３Ａにおける再利用水循環ポンプ３Ｂの出側部分に再利用水送出路３Ｆが接続され、その再利用水送出路３Ｆには再利用水送出バルブ３Ｇが配設されている。
【００１６】
そして、凍結分離運転時には図２に示すように、廃水供給バルブ２Ｃおよび廃水返送バルブ２Ｅを開け、再利用水循環バルブ３Ｃおよび再利用水供給バルブ３Ｅを閉めた状態で、冷凍機４Ｆ、廃水供給ポンプ２Ｂおよび送水ポンプ４Ｐを作動させる。これにより、廃水槽２に貯留されている廃水が、廃水供給路２Ａを介して散水器４Ｓに供給され、散水器４Ｓから蓄熱槽４Ｔ内に散布される。散布廃水は冷却コイル４Ｃの表面または冷却コイル４Ｃに付着した氷Ｃの表面を液膜状をなして巡りながら流下し、その流下過程で流下廃水が冷却され、流下廃水の純水分の一部のみが冷却コイル４Ｃの表面または冷却コイル付着氷Ｃの表面に着氷し、残部は濃縮された廃水（濃縮分）になる。これによって、凍結濃縮による水分と濃縮分とへの分離がなされる。そしてこの残部濃縮分は、廃水の連続循環によって順次当該着氷部位を通り流下する廃水に順次取込まれ、洗い流される。かかる濃縮分を取り込みつつ流下し貯水部４Ｗに到達した廃水は廃水返送路２Ｄを介して廃水槽２に返送されて貯留廃水と混合された後、当該混合廃水が再度散水器４Ｓへと連続的に循環される。かかる廃水槽２と蓄熱槽４Ｔとの間の廃水連続循環において、廃水中の実質的に水のみが氷となり冷却コイル４Ｃに蓄えられ、不純物は蓄氷には取り込まれずに循環し続けるので、循環する廃水の不純物濃度が経時的に高くなるとともに、廃水から純粋な水が氷として分離されることになる。
【００１７】
特徴的には、前述のとおり冷却コイル付着氷Ｃの表面を常に流下廃水が舐めるように流下し濃縮分を取り込み洗浄するので、濃縮分に含まれる不純物が一ヶ所に高濃度で留まりにくくなり、そのため製造した氷に不純物が取り込まれにくいとともに、製氷効率も高くなる。その結果、廃水の９０％以上を実質的に純水分のみからなる氷として蓄えることができる。
【００１８】
かかる凍結分離が終了したならば、図３に示すように、冷凍機４Ｆおよび廃水供給ポンプ２Ｂを停止させ、廃水供給バルブ２Ｃおよび廃水返送バルブ２Ｅを閉めるとともに排出バルブ２Ｇを開け、廃水槽２に残留している濃縮廃水を排出路２Ｆを介して排出させる。この排出が終了したら排出バルブ２Ｇを閉じる。なお、この濃縮廃水の排出は、次述の再利用水製造運転中に行っても良い。
【００１９】
続いて、少なくとも再利用水供給バルブ３Ｅを開けるとともに再利用水循環ポンプ３Ｂを作動させて、再利用水製造運転に入る。本発明では単に蓄熱槽４Ｔ内に蓄えた氷を自然にあるいは製氷コイル内に温熱媒体を通すことにより解氷させ、これを再利用水供給路３Ｄを介して再利用水槽３に供給し、この再利用水槽３から適宜再利用先へ供給させることもできるが、再利用水は氷として蓄えられているのでその蓄えた熱を有効利用するほうが好ましい。
【００２０】
したがって、例えば図４にも示すように、冷凍機４Ｆおよび廃水供給ポンプ２Ｂを停止させ、廃水供給バルブ２Ｃ、廃水返送バルブ２Ｅおよび再利用水送出バルブ３Ｇを閉めた状態で、再利用水供給バルブ３Ｅおよび再利用水循環バルブ３Ｃを開けるとともに、送水ポンプ４Ｐおよび再利用水循環ポンプ３Ｂを作動させることで、再利用水製造運転を開始させ、清水を再利用水槽３、再利用循環路３Ａ、蓄熱槽４Ｔ、再利用水槽３の順に循環させる。始動時に蓄熱槽４Ｔの貯水部４Ｗ内または再利用水槽３内に、清水が存在しない場合には、これらに対して清水を給水してから始動させることができる。
【００２１】
循環清水は、蓄熱槽４Ｔ内において散水器４Ｓから散布され、対応する各冷却コイル４Ｃの表面または冷却コイル付着氷の表面を液膜状をなして巡りながら流下し、その流下過程で流下水を冷却コイル付着氷（貯水部４Ｗに落下した氷含む）Ｃにより冷却され、その際の解氷水とともに貯水部４Ｗに至り、再利用水供給路３Ｄを経て再利用水槽３に供給される。この再利用水槽３内の貯留冷水は、空調負荷等の冷水利用装置または設備５へ送られて冷熱を与え、自身は温められた後に再び蓄熱槽４Ｔに供給され、再度冷却されて再利用水槽３に戻る。
【００２２】
さらに蓄熱槽４Ｔ内に蓄えた氷がなくなると、もはや冷水の製造はできなくなるので、この時点で再利用水循環バルブ３Ｃを閉じ、再利用水送出バルブ３Ｇを開け、再利用水送出路３Ｆを介してトイレ等の再利用先へ送給する。
【００２３】
かくして、廃水処理コストを低下させることができ、また大半の水を再利用することができるとともに、凍結分離の際に氷として蓄えた熱を有効利用できるようになる。
【００２４】
ところで、前述発電システムのように終日連続的に廃水（ボイラー廃水等）が発生する場合、少なくとも廃水を連続的に受け入れる必要があるが、かかる受入は本基本形態の装置には不向きである。そこで、次述の第１および第２応用形態を採用することを推奨する。
【００２５】
＜第１の応用形態＞
第１の応用形態の凍結分離装置１０は、図５に示すように、前述基本形態に対して廃水槽の数を２つに増加させるとともに、廃水供給源からの廃水を第１および第２廃水槽２０，２１のいずれか一方にのみ選択的に補給しうるようになし、更に各廃水槽２０，２１内の貯留廃水を選択的に流下液膜式氷蓄熱装置４に対してそれぞれ供給し得るようになしたものである。他の構成は前述基本形態と同様であるので、敢えて同じ符号を付して説明を略す。
【００２６】
図示例では、各廃水槽２０，２１に対して第１および第２廃水補給路２０Ｊ，２１Ｊをそれぞれ連通させるとともに、各廃水補給路２０Ｊ，２１Ｊに第１および第２廃水補給バルブ２０Ｋ，２１Ｋをそれぞれ配設することで、廃水供給源からの廃水を第１および第２廃水槽２０，２１のいずれか一方にのみ選択的に補給しうるようになしている。
【００２７】
また、第１廃水槽２０を第１廃水供給路２０Ａを介して、第２廃水槽２１を第２廃水供給路２１Ａを介してそれぞれ廃水供給路２Ａに接続し、氷蓄熱装置４の散水器４Ｓに対して連通させるとともに、第１廃水供給路２０Ａには第１廃水供給バルブ２０Ｃを配設し、第２廃水供給路２１Ａには第２廃水供給バルブ２１Ｃを配設することで、各廃水槽２０，２１内の貯留廃水を選択的に流下液膜式氷蓄熱装置４に対してそれぞれ供給し得るようになしている。一方、蓄熱槽４Ｔの貯水部４Ｗは、送水ポンプ４Ｐおよび廃水返送路２Ｄを介し、更に第１廃水返送路２０Ｄを介して第１廃水槽２０に、および第２廃水返送路２１Ｄを介して第２廃水槽２１にそれぞれ接続されている。
【００２８】
さらに、各廃水槽２０，２１内には、第１および第２排出路２０Ｆ，２１Ｆがそれぞれ連通しており、各排出路２０Ｆ，２１Ｆには、第１および第２排出バルブ２０Ｇ，２１Ｇがそれぞれ配設されている。
【００２９】
かかる装置構成の下、凍結分離運転および再利用水製造運転を交互に行い、各凍結分離運転の間（ある凍結分離運転の終了以降、次の凍結分離運転の開始以前）において廃水を収集する廃水槽を切り替えるとともに、各凍結分離運転時には廃水収集を行っていない廃水槽の貯留廃水を蓄熱槽に供給することで廃水の連続受入が可能となる。
【００３０】
以下、この具体例について詳説する。
例えば、いま蓄熱槽４Ｔ内に氷が蓄えられており、これを利用して再利用水製造運転を行っているものとし、また、当該再利用水製造運転の前の凍結分離運転から、第１廃水補給バルブ２０Ｋを開け第２廃水補給バルブ２１Ｋを閉じて廃水供給源からの廃水を第１廃水槽２０にのみ収集し貯留しているものとする。
【００３１】
当該再利用水製造運転を終えると、次の凍結分離運転に入る際、第１廃水補給バルブ２０Ｋを閉じ第２廃水補給バルブ２１Ｋを開けて、廃水供給源からの廃水を第１廃水槽２０へ収集するのを止め、第２廃水槽２１へ収集するように切り替える。また、第１廃水供給バルブ２０Ｃ、廃水供給バルブ２Ｃ、第１廃水返送バルブ２０Ｅを開け、再利用水循環バルブ３Ｃおよび再利用水供給バルブ３Ｅを閉じるとともに、廃水供給ポンプ２Ｂおよび送水ポンプ４Ｐを作動させて、第１廃水槽２０に貯留されている廃水を氷蓄熱装置４の散水器４Ｓに対して供給して凍結分離運転を行う。蓄熱槽４Ｔに供給された廃水は、冷却コイル４Ｃ表面を流下する過程で冷却され着氷する。冷却コイル４Ｃに着氷せずに、貯水部４Ｗに至った廃水は、送水ポンプ４Ｐにより第１廃水槽２０に返送される。この凍結分離運転を終えると、蓄熱槽４Ｔ内には氷が蓄えられる一方、第１廃水槽２０内には濃縮廃水が残留する。
【００３２】
続いて第１排出バルブ２０Ｇを開けて、第１廃水槽２０内に残留した濃縮廃水を第１排出路２０Ｆを介して排出させる。また、第１廃水供給バルブ２０Ｃおよび廃水供給バルブ２Ｃを閉じ、再利用水循環バルブ３Ｃおよび再利用水供給バルブ３Ｅを開けるとともに、送水ポンプ４Ｐおよび再利用水循環ポンプ３Ｂを作動させて再利用水製造運転に入る。再利用水製造運転においては、蓄熱槽４Ｔ内の解氷清水（冷水）を再利用水槽３、再利用循環路３Ａ、蓄熱槽４Ｔ、再利用水槽３の順に循環させる。循環清水は、蓄熱槽４Ｔを通過する毎に冷却されつつ、空調負荷５へ連続的に冷熱を与える。蓄熱槽４Ｔ内に蓄えた氷がなくなると、もはや冷水の製造はできなくなるので、この時点で再利用水循環バルブ３Ｃを閉じ、再利用水送出バルブ３Ｇを開け、再利用水送出路３Ｆを介してトイレ等の再利用先へ送給する。
一方、第２廃水槽２１はかかる再利用水運転中も引き続き、廃水供給源からの廃水を収集貯留する。
【００３３】
次いで、この再利用水製造運転を終えたならば、再利用水循環バルブ３Ｃおよび再利用水供給バルブ３Ｅを閉じるとともに再利用水循環ポンプ３Ｂを停止させ、次の凍結分離運転に入る。今度は第１廃水補給バルブ２０Ｋを開け第２廃水補給バルブ２１Ｋを閉じて、廃水供給源からの廃水を第２廃水槽２１へ収集するのを止めて、第１廃水槽２０へ収集するように切り替えるとともに、第２廃水供給バルブ２１Ｃおよび廃水供給バルブ２Ｃを開けて、第２廃水槽２１に貯留されている廃水を氷蓄熱装置４の散水器４Ｓに対して供給して凍結分離運転を行う。この凍結分離運転を終えると、蓄熱槽４Ｔ内には氷が蓄えられる一方、第２廃水槽２１内には濃縮廃水が残留する。
【００３４】
そこで、続いて第２排出バルブ２１Ｇを開けて第２廃水槽２１内に残留した濃縮廃水を第２排出路２１Ｆを介して排出させるとともに、第２廃水槽２１の貯留廃水を利用した凍結分離運転により蓄えた氷を解氷させて再利用水製造運転に入る。第１廃水槽２０はかかる再利用水運転中も引き続き、廃水供給源からの廃水を収集貯留する。
【００３５】
以降は、かかる工程を繰り返し行うことによって、常にいずれか一方の廃水槽を廃水の受入に使用できるようになるので、廃水の連続受け入れが可能となる。また、本第１形態によれば、例えば夜間において比較的に安い夜間電力を利用して冷凍機やポンプを作動させて凍結分離運転を行い、昼間は再利用水製造運転を行うとともに、製造した冷水を空調機等で利用することもできる。かかる運転形態の具体的なタイムフローを図６に示した。同図のフローは、第１および第２廃水槽が１日分の廃水を貯留可能である場合の例を示しており、廃水を収集する廃水槽が１日毎に夜１０時に切り替えられ、廃水収集を行っていない廃水槽は、夜１０時から凍結分離運転に使用され、前回の廃水収集で貯留した廃水を氷蓄熱装置に供給するようになっており、また、再利用水製造運転と記載されている朝８時〜夜の１０時までの時間帯では濃縮水を排出させる他には何も行わないようになっている。図示しないが、同様に夜間凍結分離運転を行い、昼間の所定時間、例えば空調負荷が大きくなる午後１時〜午後４時までの３時間だけ再利用水製造運転を行うようにすることもできる。
【００３６】
他方、本第１応用形態では、氷蓄熱装置が一つしかないため、廃水の凍結分離と再利用水製造とを併行して行うことはできない。またそのため再利用水の連続製造は不可能である。そこで、廃水の凍結分離と再利用水製造とを併行して行うことが可能な第２応用形態をも提案する。
【００３７】
＜第２の応用形態＞
第２の応用形態に係る凍結分離装置３０は、図７にも示すように、前述第１応用形態と同様に廃水槽を２つ備えるとともにそれら廃水槽２０，２１に対して廃水供給源からの廃水を選択的に供給するように構成した上で、蓄熱槽も２つ備えたものであり、第１又は第２廃水槽２０，２１の貯留廃水を、第１および第２蓄熱槽２４Ｔ，３４Ｔのいずれか一方に対して選択的に供給しうるようになし、また第１および第２蓄熱槽２４Ｔ，３４Ｔの貯留水は、第１若しくは第２廃水槽２０，２１または再利用水槽３に対してそれぞれ選択的に供給しうるようになしたものである。前述基本形態または第１応用形態と同様の構成については、敢えて同じ符号を付して説明を略す。
【００３８】
本装置３０では、第１蓄熱槽２４Ｔの貯水部２４Ｗは、第１廃水送水路２２Ｄおよび廃水返送ポンプ２４Ｐを介し、更に第１廃水返送路２０Ｄを介して第１廃水槽２０に及び第２廃水返送路２１Ｄを介して第２廃水槽２１にそれぞれ接続される一方で、第１再利用水送水路２３Ｄおよび再利用水供給路３Ｄを介して再利用水槽３に接続されており、第１廃水送水路２２Ｄには第１廃水送水バルブ２２Ｅが配設され、第１再利用水送水路２３Ｄには第１再利用水送水バルブ２３Ｅがそれぞれ配設されている。
【００３９】
同様に、第２蓄熱槽３４Ｔの貯水部３４Ｗは、第２廃水送水路３２Ｄおよび廃水返送ポンプ２４Ｐを介し、更に第１廃水返送路２０Ｄを介して第１廃水槽２０に及び第２廃水返送路２１Ｄを介して第２廃水槽２１にそれぞれ接続される一方で、第２再利用水送水路３３Ｄおよび再利用水供給路３Ｄを介して再利用水槽３に接続されており、第２廃水送水路３２Ｄには第２廃水送水バルブ３２Ｅが配設され、第２再利用水送水路３３Ｄには第２再利用水送水バルブ３３Ｅがそれぞれ配設されている。
【００４０】
また、第１廃水槽２０は、第１廃水供給路２０Ａおよび廃水供給路２Ａを介し、更に第１廃水受入路２２Ａを介して第１蓄熱槽２４Ｔの散水器２４Ｓへ接続されるとともに第２廃水受入路３２Ａを介して第２蓄熱槽３４Ｔの散水器３４Ｓへ接続されている。一方、第２廃水槽２１は、第２廃水供給路２１Ａおよび廃水供給路２Ａを介し、更に第１廃水受入路２２Ａを介して第１蓄熱槽２４Ｔの散水器２４Ｓへ接続されるとともに第２廃水受入路３２Ａを介して第２蓄熱槽３４Ｔの散水器３４Ｓへ接続されている。そして、廃水供給路２Ａには廃水供給ポンプ２Ｂが配設されるとともに、第１廃水受入路２２Ａには第１廃水受入バルブ２４Ｘが配設され、第２廃水受入路３２Ａには第２廃水受入バルブ３４Ｘが配設されている。かくして、各廃水槽２０，２１内の貯留廃水を選択的に第１または第２蓄熱槽に対してそれぞれ供給し得るようになしている。
【００４１】
さらに、再利用水槽３が再利用水循環路３Ａを介し、更に第１再利用水循環路２３Ａを介して第１蓄熱槽２４Ｔの散水器２４Ｓに接続されるとともに第２再利用水循環路３３Ａを介して第２蓄熱槽３４Ｔの散水器３４Ｓに接続されており、第１再利用水循環路２３Ａには第１再利用水循環バルブ２３Ｃが配設され、第２再利用水循環路３３Ａには第２再利用水循環バルブ３３Ｃが配設されている。
【００４２】
他方、本装置３０では、蓄熱槽を二つ備えているものの、後述のように両者が同時に凍結分離運転に使用されることはないので冷凍機４Ｆは１台のままで、これからの製氷用冷媒を第１蓄熱槽２４Ｔの冷却コイル２４Ｃおよび第２蓄熱槽３４Ｔの冷却コイル３４Ｃのいずれか一方に対して選択的に供給できるように構成している。しかし、蓄熱槽１つあたり冷凍機を設けることもできる。
【００４３】
かくして、いずれか一方の蓄熱槽２４Ｔもしくは３４Ｔを使用して凍結分離運転を行うとともに、これと併行して他方の蓄熱槽２４Ｔもしくは３４Ｔを使用して再利用水製造運転を行うことができるようになる。
【００４４】
また、廃水供給源からの廃水を、いずれか一方の廃水槽２０もしくは２１にのみ収集して貯留するとともに、他方の廃水槽２０もしくは２１に収集されている貯留廃水を凍結分離運転中の蓄熱槽２４Ｔもしくは３４Ｔに対し供給して氷として蓄えさせ、一方の廃水槽２０もしくは２１の貯留量が所定量となったならば、廃水供給源からの廃水を、一方の廃水槽２０もしくは２１へ収集するのを止めて他方の廃水槽２１もしくは２０へ収集するように切り替えるとともに、一方の廃水槽２０もしくは２１の貯留廃水を凍結分離運転中の蓄熱槽２４Ｔもしくは３４Ｔに対し供給して氷として蓄えさせるようにすることで、廃水の連続受け入れも可能となる。
以下、具体的な運転形態について図８に示すタイムフロー例に基づいて詳説する。
先ず、各蓄熱槽２４Ｔ，３４Ｔは、再利用水製造運転および凍結分離運転を交互に行うものとする。また、各再利用水製造運転時間を等しくし、および各凍結分離運転時間を等しくするとともに、各再利用水製造運転時間は、再利用水製造および凍結分離運転１サイクルに要する時間を蓄熱槽の総数で除して得られる時間とする。よって各蓄熱槽の各凍結分離運転時間は、１サイクルに要する時間から再利用水製造運転時間を差し引いて得られる。
したがって図示例の場合、氷蓄熱装置２４は２つの蓄熱槽２４Ｔ，３４Ｔを有しており、各蓄熱槽２４Ｔ，３４Ｔの再利用水製造および凍結分離運転１サイクルに要する時間を２時間とすると、各蓄熱槽の各再利用水製造運転時間および各凍結分離運転時間はそれぞれ１時間となる。また図示しないが、例えば蓄熱槽が３つで１サイクルに要する時間を１時間３０分とした場合には、各蓄熱槽の各再利用水製造運転時間は３０分、各蓄熱槽の各凍結離運転時間は１時間となる。
【００４５】
そして、常にいずれか１つの蓄熱槽だけが再利用水製造運転を行い、その際には他の蓄熱槽は凍結分離運転を行うように、各蓄熱槽２０，２１の運転時間がずらされるものとする。また、各廃水槽２０，２１は凍結分離運転時間分の廃水量を貯留できるものとする。
【００４６】
（第１段階）
いま、図８のタイムフローで午前８時であるとすると、第１蓄熱槽２４Ｔが再利用水製造運転を終えて凍結分離運転を開始し、逆に第２蓄熱槽３４Ｔが凍結分離運転を終えて再利用水製造運転を開始するようになる。一方、第１廃水槽２０は廃水収集を終えて凍結分離運転に入り、逆に第２廃水槽２１は第２蓄熱槽とともに凍結分離運転を終えて廃水収集を開始するようになる。
【００４７】
すなわち、この時点で第１廃水槽２０の貯留水量は１時間分の廃水量となっているので、第１廃水補給バルブ２０Ｋおよび第２廃水供給バルブ２１Ｃを閉じ第２廃水補給バルブ２１Ｋを開けて、廃水を第１廃水槽２０へ供給するのを止めて第２廃水補給路２１Ｊを介して第２廃水槽２１のみへ供給するように切り替える。
【００４８】
またこの廃水収集槽の切り替えとともに、第１廃水供給バルブ２０Ｃ、第１廃水受入バルブ２４Ｘ、第１廃水送水バルブ２２Ｅおよび第１廃水返送バルブ２０Ｅを開け、第１再利用水送水バルブ２３Ｅおよび第１再利用水循環バルブ２３Ｃを閉じるとともに、製造廃水返送ポンプ２４Ｐを作動させる。また、冷凍機４Ｆも作動させ、第１蓄熱槽２４Ｔの冷却コイル２４Ｃに対して製氷用冷媒を循環させるようにする。これにより、第１廃水槽２０の貯留廃水は、第１廃水供給路２０Ａ、廃水供給路２Ａおよび第１廃水受入路２２Ａ、ならびに第１廃水送水路２２Ｄおよび第１廃水返送路２０Ｄを介して、当該第１廃水槽２０と第１蓄熱槽２４Ｔとの間でだけ循環し、その循環過程で、第１蓄熱槽２４Ｔ内において冷却コイル２４Ｃにより冷却され徐々に冷却コイルに着氷するようになる。
【００４９】
一方、第２蓄熱槽３４Ｔは、当該解氷運転に先だって冷却コイル３４Ｃに氷を蓄えているので、これを利用して再利用水製造運転に入る。すなわち、第２再利用水送水バルブ３３Ｅ、再利用水送水バルブ３Ｅ、第２再利用水循環バルブ３３Ｃを開け、第２廃水受入バルブ３４Ｘ、第２廃水送水バルブ３２Ｅを閉じるとともに、再利用水送水ポンプ２４Ｑおよび再利用水循環ポンプ３Ｂを作動させ、第２蓄熱槽３４Ｔの貯水部３４Ｗの解氷水を、第２再利用水送水路３３Ｄおよび再利用水供給路３Ｄを介して再利用水槽３に対して順次供給するとともに、この再利用水槽の貯留冷水を再利用水循環路３Ａおよび空調負荷５を介し、更に第２再利用水循環路３３Ａを介して第２蓄熱槽３４Ｔの散水器３４Ｓへ供給し、第２蓄熱槽３４Ｔ内の氷により冷却してから再利用水槽３へと循環させる。
【００５０】
かくして、第１蓄熱槽２４Ｔおよび第１廃水槽２０が凍結分離運転に使用されるとともに、これと併行して、第２蓄熱槽３４Ｔが再利用水製造運転に使用され、かつ第２廃水槽２１は廃水の収集貯留に使用されるようになる。
【００５１】
（第２段階）
そして１時間経過後、今度は反対に第２廃水槽２１の貯留水量は１時間分の廃水量となっているので、第２廃水補給バルブ２１Ｋおよび第１廃水供給バルブ２０Ｃを閉じ第１廃水補給バルブ２０Ｋを開けて、廃水を第２廃水槽２１へ供給するのを止めて第１廃水槽２０のみへ供給するように切り替える。
【００５２】
またこの廃水収集槽の切り替えとともに、第２廃水供給バルブ２１Ｃ、第２廃水受入バルブ３４Ｘ、第２廃水送水バルブ３２Ｅおよび第２廃水返送バルブ２１Ｅを開け、第２再利用水送水バルブ３３Ｅおよび第２再利用水循環バルブ３３Ｃを閉じるとともに、製造廃水返送ポンプ２４Ｐを作動させる。また、冷凍機４Ｆから供給される製氷用冷媒を第２蓄熱槽３４Ｔの冷却コイル３４Ｃへ供給するようにする。これにより、第２廃水槽２１の貯留廃水は第２廃水供給路２１Ａ、廃水供給路２Ａおよび第２廃水受入路３２Ａ、ならびに第２廃水送水路３２Ｄおよび第２廃水返送路２１Ｄを介して、第２廃水槽２１と第２蓄熱槽３４Ｔとの間でだけ循環し、その循環過程で、第２蓄熱槽３４Ｔ内において冷却コイル３４Ｃにより冷却され徐々に冷却コイルに着氷するようになる。
【００５３】
一方、第１蓄熱槽２４Ｔは、当該解氷運転に先だって冷却コイル２４Ｃに氷を蓄えているので、これを利用して再利用水製造運転に入る。すなわち、第１再利用水送水バルブ２３Ｅ、再利用水供給バルブ３Ｅ、第１再利用水循環バルブ２３Ｃを開け、第１廃水受入バルブ２４Ｘ、第１廃水送水バルブ２２Ｅを閉じるとともに、再利用水送水ポンプ２４Ｑおよび再利用水循環ポンプ３Ｂを作動させ、第１蓄熱槽２４Ｔの貯水部２４Ｗの解氷水を、第１再利用水送水路２３Ｄおよび再利用水供給路３Ｄを介して再利用水槽３に対して順次供給するとともに、この再利用水槽３の貯留冷水を再利用水循環路３Ａおよび空調負荷５を介し、更に第１再利用水循環路２３Ａを介して第１蓄熱槽２４Ｔの散水器２４Ｓへ供給し、第１蓄熱槽２４Ｔ内の氷により冷却してから再利用水槽３へと循環させる。
【００５４】
かくして、第２蓄熱槽３４Ｔおよび第２廃水槽２１が凍結分離運転に使用されるとともに、これと併行して、第１蓄熱槽２４Ｔが再利用水製造運転に使用され、かつ第１廃水槽２０は廃水の収集貯留に使用されるようになる。
【００５５】
（以降の段階）
以降は、かかる第１〜第２段階を１サイクルとして繰り返し行う。かくして、いずれか一方の蓄熱槽が凍結分離運転を行い、これと併行して他方が再利用水製造運転を行うことができるので、もって再利用水の連続供給および廃水の連続受け入れ、すなわち連続処理が可能となる。
【００５６】
＜その他＞
図示しないが、凍結分離運転中適宜または凍結分離運転終了後に、例えば散布器から蓄熱槽内に清水を散布し、冷却コイルに蓄えられた氷の表面を洗浄するのは好ましい。これにより、氷の表面に付着した廃水または濃縮廃水を洗い流すことができ、より不純物濃度の低い再利用水の製造が可能となる。
【００５７】
＜実験例＞
廃水の代わりに塩水を用い、流下液膜式氷蓄熱装置を採用した本発明装置と、浸管式氷蓄熱装置を採用した装置とにより凍結分離実験をそれぞれ行った。その結果、本発明装置における冷却コイル付着氷中の塩分濃度は、浸管式氷蓄熱装置を採用した装置における冷却コイル付着氷中の塩分濃度の２／３となった。この結果からも、本発明装置では前述の流下廃水による濃縮分の取込洗浄によって製造氷に不純物が取り込まれにくいこと、およびそれによって格段に優れた凍結分離効果を奏することが判る。
【００５８】
【発明の効果】
以上のとおり、本発明によれば、廃水を実質的に純水分のみからなる氷として蓄えることができ、その氷を冷熱源としてあるいは水源として再利用できるので、廃水処理費のコストダウンを図ることができるようになる。しかも、製氷に際して氷中に不純物が取り込まれにくく、蓄氷中の不純物含有量を格段に低減することができるので解氷水を再利用しやすくなるとともに、製氷量も格段に向上させることができるので廃水の再利用効率を著しく高めることができるようになる。
【図面の簡単な説明】
【図１】本発明に係る凍結分離装置の基本形態を示すフロー図である。
【図２】その凍結分離運転状態を示す、フロー図である。
【図３】その濃縮水廃水状態を示す、フロー図である。
【図４】その再利用水製造運転状態を示す、フロー図である。
【図５】本発明に係る凍結分離装置の第１の応用形態を示す、フロー図である。
【図６】第１の応用形態に好適なタイムフロー図である。
【図７】本発明に係る凍結分離装置の第２の応用形態を示す、フロー図である。
【図８】第２の応用形態に好適なタイムフロー図である。
【図９】発電システムのフロー図である。
【符号の説明】
１…凍結分離装置、２…廃水槽、３…再利用水槽、４…流下液膜式氷蓄熱装置。[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a freeze separation apparatus.
[0002]
[Prior art]
  For example, as shown in FIG. 9, steam generated in the steam boiler 102 is supplied to the steam turbine 103, the steam turbine 103 is rotationally driven, and the rotational driving force is transmitted to the generator 104 to generate electric power. The steam used in 103 is supplied to the condenser 106, where it is cooled by the refrigerant supplied from the condensate cooling tower 105 to be condensed, and the condensed water is returned to the steam boiler 102 via the return water tank 107. In the power generation system 100 using a steam turbine used for generating steam, blow water is discharged from the steam boiler 102 and the cooling tower 105, respectively.
[0003]
  Conventionally, wastewater such as blow water has been outsourced to a wastewater treatment specialist.
[0004]
[Problems to be solved by the invention]
  However, when outsourcing wastewater treatment to a wastewater treatment specialist, the problem is that wastewater treatment costs increase.
[0005]
  Therefore, the main problem of the present invention is to reduce the cost of wastewater treatment.
[0006]
[Means for Solving the Problems]
  The present invention that has solved the above problems provides a cooling coil through which ice-making refrigerant passes in a heat storage tank, a sprinkler is provided above the cooling coil, a water storage part is provided below the cooling coil, and the water storage part is stored. A falling liquid film type ice storage device configured to maintain the water surface spaced apart below the cooling coil; and
  A wastewater tank that collects and stores wastewater from a wastewater supply source, and a reuse water tank,
  During freeze-separation operation, waste water stored in the waste water tank is continuously circulated between the waste water tank and the falling liquid film type ice heat storage device, and the circulating waste water in the falling liquid film type ice heat storage device. Sprinkling from the sprinkler, the sprinkling water flows down the surface of the cooling coil or the ice attached to the cooling coil in the form of a liquid film, and in the flow-down process, substantially pure water out of the flowing down wastewater. While only a part of the water is icing on the surface of the cooling coil or the ice surface adhering to the cooling coil, the remaining concentrated portion is taken into the falling waste water flowing down through the icing part and washed away, and the water storage unit The waste water that has reached is configured to be returned to the waste water tank,
  It is configured to discharge the concentrated waste water remaining in the waste water tank after the freeze separation operation is completed, and
  During the reuse water production operation, the ice stored in the cooling coil is defrosted and the deiced water is removed without supplying the wastewater from the wastewater tank to the sprinkler and returning the wastewater from the reservoir to the wastewater tank. The freeze separation device is configured to be supplied to the reuse water tank.
[0007]
  In the present invention, the falling liquid film type ice heat storage device includes a plurality of heat storage tanks and performs the freeze-separation operation using at least one heat storage tank, and at the same time, at least one of the remaining heat storage tanks. It is preferable that the recycle water production operation is performed using one of them.
[0008]
  In addition, at least two of the wastewater tanks, and configured to selectively supply wastewater from the wastewater supply source to the wastewater tanks,
  The freeze separation operation and the reuse water production operation are configured to be performed alternately,
  A wastewater tank for collecting the wastewater during each freeze separation operation.In the wastewater tank that discharged the concentrated wastewaterIn addition to switching, it is also preferable that the wastewater storage wastewater not collected at each freezing operation is supplied to the heat storage tank.
[0009]
  In addition, at least two of the wastewater tanks, and configured to selectively supply wastewater from the wastewater supply source to the wastewater tanks,
  On the other hand, the falling liquid film type ice heat storage device includes a plurality of heat storage tanks and performs the freeze separation operation using at least one heat storage tank, and at the same time, at least one of the remaining heat storage tanks is used. Configured to perform the reuse water production operation using,,
  The wastewater from the wastewater supply source is collected and stored only in one of the wastewater tanks, and the stored wastewater collected in the other wastewater tank is supplied to the heat storage tank during the freeze separation operation as ice. Store,
  When the storage amount of the one wastewater tank becomes a predetermined amount, the wastewater from the wastewater supply source is switched to stop collecting in the one wastewater tank and collect in the other wastewater tank, It is also preferable that the stored wastewater in the one wastewater tank is supplied to the heat storage tank during the freeze separation operation and stored as ice.
[0010]
  <Action>
  The device according to the present invention separates waste water into fresh water and concentrated waste water by the freeze separation action of the ice heat storage device, and also recycles the ice stored in the ice heat storage device to obtain reusable fresh water. Can be reduced, and most of the water can be reused.
[0011]
  In particular, when icing on the cooling coil, only a part of the pure water of the falling wastewater becomes ice and adheres to the surface of the cooling coil or the ice attached to the coil, with the remainder remaining as concentrated wastewater (concentrated). Thus, separation by freeze concentration is performed. Then, the remaining concentrated portion is sequentially taken into the wastewater flowing down through the icing site by continuous circulation of the wastewater, and washed away. Therefore, the impurities contained in the concentrated portion are unlikely to remain at a high concentration in one place, so that the impurities are not easily taken into the manufactured ice and the icing efficiency is high (easy to icing). As a result, 90% or more of the waste water can be stored as pure ice. On the other hand, according to a so-called submerged ice heat storage device that performs ice making with the cooling coil immersed in stored water, it can be made pure ice only up to about 50%. On the other hand, the falling wastewater that has reached the reservoir is concentrated only by the pure water that has landed on the cooling coil, and this is returned to the wastewater tank and mixed with the stored wastewater. It is continuously circulated to the water sprayer of the heat storage device. Therefore, the circulating wastewater is concentrated over time due to the freeze concentration action.
[0012]
  In addition, the falling liquid film type ice heat storage device has high ice melting efficiency, and the temperature of the ice melting cold water does not substantially increase until the ice runs out. Therefore, the ice melting cold water is used in other equipment such as a refrigerant for air conditioning. There also exists an advantage which can be utilized suitably as a refrigerant | coolant.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
  <Basic form>
  FIG. 1 shows a freeze separation apparatus example 1 to which the present invention is applied. This freeze separation apparatus 1 is provided with a plurality of cooling coils 4C through which ice-making refrigerant from a refrigerator 4F flows in a heat storage tank 4T, A plurality of water sprinklers 4S are provided corresponding to the upper side of each cooling coil 4C, a water storage part 4W is provided below the cooling coil 4C, and the water storage surface of the water storage part 4W is spaced apart and maintained below the cooling coil 4C. The falling liquid film type ice heat storage device 4 (not shown) receives the ice that has fallen off the cooling coil 4C when deicing above the reservoir water surface and below the cooling coil 4C in the falling liquid film type ice heat storage device 4 A reticulated water tank 2 for collecting and storing waste water supplied from a waste water supply source, and a reuse water tank 3 for storing produced reuse water.
[0014]
  The waste water tank 2 is connected to the sprinkler 4S of the falling film ice heat storage device 4 through the waste water supply path 2A, and the waste water supply path 2A is provided with a waste water supply pump 2B and a waste water supply valve 2C, respectively. ing. On the other hand, the water storage section 4W of the heat storage tank 4T is connected to the waste water tank 2 via the water pump 4P and the waste water return path 2D, and to the reuse water tank 3 via the water pump 4P and the reuse water supply path 3D, respectively. The waste water return path 2D is provided with a waste water return valve 2E, and the reuse water supply path 3D is provided with a reuse water supply valve 3E. Further, a discharge passage 2F communicates with the waste water tank 2, and a discharge valve 2G is disposed in the discharge passage 2F.
[0015]
  On the other hand, in the illustrated example, the reused water tank 3 is connected to the sprinkler 4S of the falling liquid film type ice heat storage device 4, and the reused water circulation path 3A includes a reused water circulation pump 3B and a reused water circulation valve 3C in this order. In addition, a reuse water delivery path 3F is connected to the outlet side of the reuse water circulation pump 3B in the reuse water circulation path 3A, and a reuse water delivery valve 3G is arranged in the reuse water delivery path 3F. It is installed.
[0016]
  Then, as shown in FIG. 2, during the freeze separation operation, the waste water supply valve 2C and the waste water return valve 2E are opened, and the reuse water circulation valve 3C and the reuse water supply valve 3E are closed. 2B and the water pump 4P are operated. Thereby, the waste water stored in the waste water tank 2 is supplied to the sprinkler 4S through the waste water supply path 2A, and is sprayed from the sprinkler 4S into the heat storage tank 4T. The sprayed wastewater flows down the surface of the cooling coil 4C or the surface of the ice C attached to the cooling coil 4C while forming a liquid film, and the falling wastewater is cooled in the flow process, and only a part of the pure water of the flowing wastewater is cooled. Is icing on the surface of the cooling coil 4C or the surface of the cooling coil adhering ice C, and the remainder becomes concentrated waste water (concentrated component). As a result, the water and the concentrated component are separated by freeze concentration. Then, the remaining concentrated portion is sequentially taken into the wastewater flowing down through the icing site by continuous circulation of the wastewater, and washed away. The wastewater that flows down while reaching the reservoir 4W while taking in the concentrated component is returned to the wastewater tank 2 through the wastewater return path 2D and mixed with the stored wastewater, and then the mixed wastewater is continuously supplied to the sprinkler 4S again. It is circulated. In the continuous wastewater circulation between the wastewater tank 2 and the heat storage tank 4T, substantially only water in the wastewater becomes ice and is stored in the cooling coil 4C, and the impurities continue to circulate without being taken into the ice storage. As the concentration of impurities in the wastewater increases over time, pure water is separated from the wastewater as ice.
[0017]
  Characteristically, as mentioned above, the surface of the cooling coil adhering ice C always flows down so that the falling wastewater licks, and the concentrated component is taken in and washed, so it becomes difficult for impurities contained in the concentrated component to remain at a high concentration in one place. Therefore, impurities are not easily taken into the manufactured ice, and the ice making efficiency is also increased. As a result, 90% or more of the waste water can be stored as ice substantially consisting of pure water.
[0018]
  When the freeze separation is completed, as shown in FIG. 3, the refrigerator 4F and the wastewater supply pump 2B are stopped, the wastewater supply valve 2C and the wastewater return valve 2E are closed, the discharge valve 2G is opened, and the wastewater tank 2 is opened. The remaining concentrated waste water is discharged through the discharge path 2F. When this discharge is completed, the discharge valve 2G is closed. This concentrated waste water may be discharged during the reuse water production operation described below.
[0019]
  Subsequently, at least the reused water supply valve 3E is opened and the reused water circulation pump 3B is operated to start the reused water production operation. In the present invention, the ice stored in the heat storage tank 4T is defrosted naturally or by passing a heating medium through an ice making coil, and this is supplied to the reuse water tank 3 via the reuse water supply path 3D. Although it can be appropriately supplied from the reuse water tank 3 to the reuse destination, since the reuse water is stored as ice, it is preferable to effectively use the stored heat.
[0020]
  Therefore, as shown in FIG. 4 for example, the refrigerating water supply valve 2F, the waste water supply valve 2E, the waste water return valve 2E, and the reuse water supply valve 3G are closed while the refrigerator 4F and the waste water supply pump 2B are stopped. 3E and the reuse water circulation valve 3C are opened, and the water supply pump 4P and the reuse water circulation pump 3B are operated to start the reuse water production operation. The fresh water is reused in the reuse water tank 3, the reuse circulation path 3A, and the heat storage tank. It is made to circulate in order of 4T and the reuse water tank 3. When fresh water does not exist in the water storage section 4W of the heat storage tank 4T or the reuse water tank 3 at the time of start-up, it can be started after supplying fresh water to these.
[0021]
  Circulating fresh water is sprayed from the water sprinkler 4S in the heat storage tank 4T, and flows down while flowing around the surface of each corresponding cooling coil 4C or the surface of the cooling coil adhering ice in the form of a liquid film. It is cooled by the cooling coil adhering ice (including ice that has fallen to the water storage unit 4W) C, reaches the water storage unit 4W together with the deicing water at that time, and is supplied to the reuse water tank 3 through the reuse water supply path 3D. The stored cold water in the reuse water tank 3 is sent to a cold water utilization device or equipment 5 such as an air-conditioning load to give cold heat, and after being warmed, it is supplied again to the heat storage tank 4T and cooled again to be reused water tank. Return to 3.
[0022]
  Further, when the ice stored in the heat storage tank 4T runs out, cold water can no longer be produced. At this time, the reuse water circulation valve 3C is closed, the reuse water delivery valve 3G is opened, and the reuse water delivery path 3F is passed through. To the restroom.
[0023]
  Thus, wastewater treatment costs can be reduced, most of the water can be reused, and the heat stored as ice during freezing and separation can be used effectively.
[0024]
  By the way, when waste water (boiler waste water or the like) is generated continuously throughout the day as in the above-described power generation system, it is necessary to continuously receive at least the waste water, but such acceptance is unsuitable for the apparatus of this basic form. Therefore, it is recommended to adopt the first and second application modes described below.
[0025]
  <First application form>
  As shown in FIG. 5, the freeze separation apparatus 10 of the first application form increases the number of waste water tanks to two with respect to the basic form described above, and uses the first and second waste water from the waste water supply source. Only one of the water tanks 20 and 21 can be selectively replenished, and the stored waste water in each of the waste water tanks 20 and 21 can be selectively supplied to the falling film ice storage device 4 respectively. It was made like that. Since other configurations are the same as those of the basic mode described above, the same reference numerals are given and description thereof is omitted.
[0026]
  In the illustrated example, the first and second waste water supply paths 20J and 21J are communicated with the waste water tanks 20 and 21, respectively, and the first and second waste water supply valves 20K and 21K are connected to the waste water supply paths 20J and 21J, respectively. By disposing each, waste water from the waste water supply source can be selectively supplied to only one of the first and second waste water tanks 20 and 21.
[0027]
  In addition, the first wastewater tank 20 is connected to the wastewater supply path 2A via the first wastewater supply path 20A and the second wastewater tank 21 is connected to the wastewater supply path 2A via the second wastewater supply path 21A. The first wastewater supply passage 20A is provided with a first wastewater supply valve 20C, and the second wastewater supply passage 21A is provided with a second wastewater supply valve 21C. The stored waste water in 20 and 21 can be selectively supplied to the falling liquid film type ice heat storage device 4. On the other hand, the water storage section 4W of the heat storage tank 4T is supplied to the first waste water tank 20 via the water pump 4P and the waste water return path 2D, further to the first waste water tank 20 via the first waste water return path 20D, and via the second waste water return path 21D. 2 Each is connected to a wastewater tank 21.
[0028]
  Further, the first and second discharge passages 20F and 21F communicate with each of the waste water tanks 20 and 21, respectively. The first and second discharge valves 20G and 21G are respectively connected to the discharge passages 20F and 21F. It is arranged.
[0029]
  Under such an apparatus configuration, waste separation in which freeze separation operation and reuse water production operation are alternately performed and waste water is collected during each freeze separation operation (after the end of one freeze separation operation and before the start of the next freeze separation operation). In addition to switching the water tank, continuous waste water can be received by supplying the stored waste water of the waste water tank that is not collecting waste water to each heat storage tank during each freeze separation operation.
[0030]
  Hereinafter, this specific example will be described in detail.
  For example, it is assumed that ice is now stored in the heat storage tank 4T, and the reused water production operation is performed using this, and from the freeze separation operation before the reused water production operation, the first It is assumed that the wastewater supply valve 20K is opened and the second wastewater supply valve 21K is closed to collect and store wastewater from the wastewater supply source only in the first wastewater tank 20.
[0031]
  When the reuse water production operation is finished, when the next freeze separation operation is started, the first wastewater supply valve 20K is closed and the second wastewater supply valve 21K is opened, and the wastewater from the wastewater supply source is sent to the first wastewater tank 20. Stop collecting and switch to collect in the second wastewater tank 21. Further, the first waste water supply valve 20C, the waste water supply valve 2C, and the first waste water return valve 20E are opened, the reuse water circulation valve 3C and the reuse water supply valve 3E are closed, and the waste water supply pump 2B and the water pump 4P are operated. Then, the wastewater stored in the first wastewater tank 20 is supplied to the sprinkler 4S of the ice heat storage device 4 to perform the freeze separation operation. The wastewater supplied to the heat storage tank 4T is cooled and icing in the process of flowing down the surface of the cooling coil 4C. The wastewater that has reached the water storage unit 4W without icing on the cooling coil 4C is returned to the first wastewater tank 20 by the water pump 4P. When this freeze separation operation is completed, ice is stored in the heat storage tank 4T, while concentrated wastewater remains in the first wastewater tank 20.
[0032]
  Subsequently, the first discharge valve 20G is opened, and the concentrated waste water remaining in the first waste water tank 20 is discharged through the first discharge path 20F. In addition, the first waste water supply valve 20C and the waste water supply valve 2C are closed, the reuse water circulation valve 3C and the reuse water supply valve 3E are opened, and the water supply pump 4P and the reuse water circulation pump 3B are operated to operate the reuse water production operation. to go into. In the reuse water manufacturing operation, the deiced fresh water (cold water) in the heat storage tank 4T is circulated in the order of the reuse water tank 3, the reuse circulation path 3A, the heat storage tank 4T, and the reuse water tank 3. Circulating fresh water continuously cools the air conditioning load 5 while being cooled every time it passes through the heat storage tank 4T. When the ice stored in the heat storage tank 4T runs out, cold water can no longer be produced. At this time, the reuse water circulation valve 3C is closed, the reuse water delivery valve 3G is opened, and the reuse water delivery path 3F is passed through. Send it to a reused place such as a toilet.
  On the other hand, the second wastewater tank 21 continues to collect and store the wastewater from the wastewater supply source even during the reuse water operation.
[0033]
  Next, when the reuse water production operation is finished, the reuse water circulation valve 3C and the reuse water supply valve 3E are closed, the reuse water circulation pump 3B is stopped, and the next freeze separation operation is started. This time, the first wastewater supply valve 20K is opened and the second wastewater supply valve 21K is closed to stop collecting the wastewater from the wastewater supply source into the second wastewater tank 21 and collect it into the first wastewater tank 20. At the same time, the second wastewater supply valve 21C and the wastewater supply valve 2C are opened, and the wastewater stored in the second wastewater tank 21 is supplied to the sprinkler 4S of the ice heat storage device 4 to perform the freeze separation operation. When this freeze separation operation is completed, ice is stored in the heat storage tank 4T, while concentrated wastewater remains in the second wastewater tank 21.
[0034]
  Accordingly, the second discharge valve 21G is subsequently opened to discharge the concentrated waste water remaining in the second waste water tank 21 through the second discharge path 21F, and the freeze separation operation using the stored waste water in the second waste water tank 21. The ice stored in step 1 is defrosted and the recycle water production operation is started. The first wastewater tank 20 continues to collect and store the wastewater from the wastewater supply source during the reuse water operation.
[0035]
  Thereafter, by repeatedly performing this process, one of the waste water tanks can always be used for receiving the waste water, so that the continuous reception of the waste water becomes possible. In addition, according to the first embodiment, for example, a refrigerator and a pump are operated by using a relatively cheap nighttime power at night to perform a freeze separation operation, and during the daytime, a recycled water production operation is performed and manufactured. Cold water can also be used with an air conditioner or the like. A specific time flow of this operation mode is shown in FIG. The flow in the figure shows an example in which the first and second wastewater tanks can store one day's worth of wastewater, and the wastewater tanks that collect wastewater are switched every day at 10:00 pm to collect wastewater. Waste water tanks that have not been used are used for freeze separation operation from 10:00 pm, and the wastewater stored in the previous wastewater collection is supplied to the ice heat storage device, and is also described as reused water production operation. During the time period from 8:00 am to 10:00 pm, nothing is done other than discharging concentrated water. Although not shown in the figure, it is also possible to perform the freeze-free operation at night and perform the reuse water production operation only for a predetermined time in the daytime, for example, for 3 hours from 1 pm to 4 pm when the air conditioning load increases.
[0036]
  On the other hand, in the first application mode, since there is only one ice heat storage device, it is not possible to perform freezing separation of waste water and production of reused water at the same time. Therefore, continuous production of reused water is impossible. Then, the 2nd application form which can perform freezing separation of wastewater and reuse water manufacture simultaneously is also proposed.
[0037]
  <Second application form>
  As shown in FIG. 7, the freeze separation device 30 according to the second application form includes two wastewater tanks as in the first application form, and supplies wastewater tanks 20 and 21 from the wastewater supply source. The waste water is configured to be selectively supplied, and two heat storage tanks are provided. The stored waste water in the first or second waste water tanks 20 and 21 is used as the first and second heat storage tanks 24T and 34T. The water stored in the first and second heat storage tanks 24T and 34T is supplied to the first or second waste water tanks 20 and 21 or the reuse water tank 3. Each can be selectively supplied. About the structure similar to the said basic form or the 1st application form, the same code | symbol is dared and description is abbreviate | omitted.
[0038]
  In the present apparatus 30, the water storage unit 24W of the first heat storage tank 24T is connected to the first waste water tank 20 via the first waste water supply path 22D and the waste water return pump 24P, and further to the first waste water tank 20 via the first waste water return path 20D. While connected to the second wastewater tank 21 via the return path 21D, the first wastewater is connected to the reused tank 3 via the first reused water supply path 23D and the reused water supply path 3D. A first wastewater water supply valve 22E is provided in the water supply path 22D, and a first reused water supply valve 23E is provided in the first reused water supply path 23D.
[0039]
  Similarly, the water storage section 34W of the second heat storage tank 34T is connected to the first waste water tank 20 via the second waste water supply path 32D and the waste water return pump 24P, and further to the first waste water tank 20 via the first waste water return path 20D. The second wastewater tank 21 is connected to the second wastewater tank 21 via the second reuse water tank 33D and the reused water supply path 3D, and is connected to the reused water tank 3 via the second reused water tank 33D. A second wastewater water supply valve 32E is disposed in 32D, and a second reused water supply valve 33E is disposed in the second reused water supply channel 33D.
[0040]
  In addition, the first wastewater tank 20 is connected to the sprinkler 24S of the first heat storage tank 24T via the first wastewater supply path 20A and the wastewater supply path 2A, and further via the first wastewater receiving path 22A and the second wastewater. It is connected to the sprinkler 34S of the second heat storage tank 34T via the receiving path 32A. On the other hand, the second wastewater tank 21 is connected to the sprinkler 24S of the first heat storage tank 24T via the second wastewater supply path 21A and the wastewater supply path 2A, and further via the first wastewater receiving path 22A and the second wastewater. It is connected to the sprinkler 34S of the second heat storage tank 34T via the receiving path 32A. The waste water supply path 2A is provided with a waste water supply pump 2B, the first waste water receiving path 22A is provided with a first waste water receiving valve 24X, and the second waste water receiving path 32A is provided with a second waste water receiving path. A valve 34X is provided. Thus, the stored waste water in each of the waste water tanks 20 and 21 can be selectively supplied to the first or second heat storage tank, respectively.
[0041]
  Further, the reuse water tank 3 is connected to the water sprayer 24S of the first heat storage tank 24T via the reuse water circulation path 3A, and further via the first reuse water circulation path 23A, and via the second reuse water circulation path 33A. It is connected to the sprinkler 34S of the second heat storage tank 34T, the first reuse water circulation path 23A is provided with the first reuse water circulation valve 23C, and the second reuse water circulation path 33A is provided with the second reuse water circulation. A valve 33C is provided.
[0042]
  On the other hand, although this apparatus 30 is provided with two heat storage tanks, both of them are not simultaneously used for the freeze separation operation as will be described later, so that only one refrigerator 4F remains, and a refrigerant for ice making in the future. Can be selectively supplied to one of the cooling coil 24C of the first heat storage tank 24T and the cooling coil 34C of the second heat storage tank 34T. However, a refrigerator can be provided for each heat storage tank.
[0043]
  Thus, either one of the heat storage tanks 24T or 34T is used for the freeze separation operation, and at the same time, the other heat storage tank 24T or 34T can be used for the reuse water production operation. Become.
[0044]
  In addition, the waste water from the waste water supply source is collected and stored only in one of the waste water tanks 20 or 21, and the stored waste water collected in the other waste water tank 20 or 21 is stored in the heat storage tank during the freeze separation operation. If it is supplied to 24T or 34T and stored as ice, and the storage amount of one wastewater tank 20 or 21 reaches a predetermined amount, wastewater from the wastewater supply source is collected in one wastewater tank 20 or 21. Is switched to collect in the other wastewater tank 21 or 20, and the stored wastewater in one wastewater tank 20 or 21 is supplied to the heat storage tank 24T or 34T during the freeze separation operation and stored as ice. By making it, continuous acceptance of wastewater is also possible.
  Hereinafter, a specific operation mode will be described in detail based on the time flow example shown in FIG.
  First, each heat storage tank 24T, 34T shall perform a reuse water manufacturing operation and a freeze separation operation alternately. In addition, each reuse water production operation time is made equal and each freeze separation operation time is made equal, and each reuse water production operation time is equal to the time required for one cycle of reuse water production and freeze separation operation. The time obtained by dividing by the total number. Therefore, each freeze separation operation time of each heat storage tank is obtained by subtracting the reuse water production operation time from the time required for one cycle.
  Therefore, in the case of the illustrated example, the ice heat storage device 24 has two heat storage tanks 24T and 34T, and the time required for one cycle of reusable water production and freeze separation operation of each of the heat storage tanks 24T and 34T is 2 hours. Each reuse water production operation time and each freeze separation operation time of each heat storage tank are each 1 hour. Although not shown, for example, when there are three heat storage tanks and the time required for one cycle is 1 hour 30 minutes, each reclaimed water production operation time of each heat storage tank is 30 minutes, and each freeze storage of each heat storage tank is The operation time is 1 hour.
[0045]
  And only one of the heat storage tanks always performs the reuse water production operation, and in that case, the operation time of each of the heat storage tanks 20 and 21 is shifted so that the other heat storage tanks perform the freeze separation operation. To do. Moreover, each wastewater tank 20 and 21 shall be able to store the amount of wastewater for freezing separation operation time.
[0046]
  (First stage)
  Now, assuming that it is 8:00 am in the time flow of FIG. 8, the first heat storage tank 24T finishes the reuse water production operation and starts the freeze separation operation, and conversely the second heat storage tank 34T finishes the freeze separation operation. The reuse water production operation will be started. On the other hand, the first wastewater tank 20 finishes the wastewater collection and enters the freeze separation operation. Conversely, the second wastewater tank 21 finishes the freeze separation operation together with the second heat storage tank and starts the wastewater collection.
[0047]
  That is, since the amount of water stored in the first wastewater tank 20 is the amount of wastewater for one hour at this time, the first wastewater supply valve 20K and the second wastewater supply valve 21C are closed and the second wastewater supply valve 21K is opened. Then, the supply of waste water to the first waste water tank 20 is stopped, and the supply is switched to supply only to the second waste water tank 21 via the second waste water supply path 21J.
[0048]
  Further, along with the switching of the waste water collection tank, the first waste water supply valve 20C, the first waste water receiving valve 24X, the first waste water feed valve 22E and the first waste water return valve 20E are opened, and the first reused water feed valve 23E and the first waste water feed valve 23E The reuse water circulation valve 23C is closed and the manufacturing wastewater return pump 24P is operated. Further, the refrigerator 4F is also operated so that the ice-making refrigerant is circulated through the cooling coil 24C of the first heat storage tank 24T. Thereby, the stored wastewater in the first wastewater tank 20 passes through the first wastewater supply path 20A, the wastewater supply path 2A, the first wastewater receiving path 22A, the first wastewater supply path 22D, and the first wastewater return path 20D. It circulates only between the first waste water tank 20 and the first heat storage tank 24T, and in the circulation process, it is cooled by the cooling coil 24C in the first heat storage tank 24T and gradually reaches the cooling coil.
[0049]
  On the other hand, since the second heat storage tank 34T stores ice in the cooling coil 34C prior to the ice melting operation, the second heat storage tank 34T enters the reuse water manufacturing operation using this. That is, the second reused water feed valve 33E, the reused water feed valve 3E, the second reused water circulation valve 33C are opened, the second wastewater receiving valve 34X and the second wastewater feedwater valve 32E are closed, and the reused water feed pump 24Q and the reuse water circulation pump 3B are operated, and the deicing water in the water storage section 34W of the second heat storage tank 34T is supplied to the reuse water tank 3 via the second reuse water supply path 33D and the reuse water supply path 3D. In addition to the sequential supply, the cold water stored in the reuse water tank is supplied to the sprinkler 34S of the second heat storage tank 34T via the reuse water circulation path 3A and the air conditioning load 5, and further via the second reuse water circulation path 33A. 2 Cooled with ice in the heat storage tank 34T and then circulated to the reused water tank 3.
[0050]
  Thus, the first heat storage tank 24T and the first wastewater tank 20 are used for the freeze separation operation, and in parallel therewith, the second heat storage tank 34T is used for the reuse water production operation, and the second wastewater tank 21 is used. Will be used for collecting and storing wastewater.
[0051]
  (Second stage)
  Then, after 1 hour has passed, the amount of stored water in the second wastewater tank 21 is the amount of wastewater for one hour, so the second wastewater supply valve 21K and the first wastewater supply valve 20C are closed to supply the first wastewater. The valve 20K is opened to stop the supply of wastewater to the second wastewater tank 21 and switch to supply only to the first wastewater tank 20.
[0052]
  Further, along with the switching of the waste water collection tank, the second waste water supply valve 21C, the second waste water receiving valve 34X, the second waste water feed valve 32E, and the second waste water return valve 21E are opened, and the second reused water feed valve 33E and second The recycled water circulation valve 33C is closed and the manufacturing wastewater return pump 24P is operated. Further, the ice-making refrigerant supplied from the refrigerator 4F is supplied to the cooling coil 34C of the second heat storage tank 34T. As a result, the stored wastewater in the second wastewater tank 21 passes through the second wastewater supply path 21A, the wastewater supply path 2A, the second wastewater receiving path 32A, the second wastewater supply path 32D, and the second wastewater return path 21D. 2 It circulates only between the waste water tank 21 and the second heat storage tank 34T, and in the circulation process, it is cooled by the cooling coil 34C in the second heat storage tank 34T and gradually reaches the cooling coil.
[0053]
  On the other hand, since the first heat storage tank 24T stores ice in the cooling coil 24C prior to the ice-melting operation, the first heat storage tank 24T enters the reuse water manufacturing operation. That is, the first reused water feed valve 23E, the reused water supply valve 3E, the first reused water circulation valve 23C are opened, the first wastewater receiving valve 24X and the first wastewater feedwater valve 22E are closed, and the reused water feed pump 24Q and the reuse water circulation pump 3B are operated, and the deicing water in the water storage section 24W of the first heat storage tank 24T is supplied to the reuse water tank 3 via the first reuse water supply path 23D and the reuse water supply path 3D. In addition to supplying sequentially, the stored cold water in the reuse water tank 3 is supplied to the sprinkler 24S of the first heat storage tank 24T via the reuse water circulation path 3A and the air conditioning load 5, and further via the first reuse water circulation path 23A. After cooling with ice in the first heat storage tank 24 </ b> T, it is circulated to the reuse water tank 3.
[0054]
  Thus, the second heat storage tank 34T and the second waste water tank 21 are used for the freeze separation operation, and in parallel therewith, the first heat storage tank 24T is used for the reuse water production operation, and the first waste water tank 20 is used. Will be used for collecting and storing wastewater.
[0055]
  (Subsequent stages)
  Thereafter, the first and second steps are repeated as one cycle. Thus, since either one of the heat storage tanks performs the freeze separation operation and the other can perform the reuse water production operation, the continuous supply of the reused water and the continuous reception of the wastewater, that is, the continuous treatment. Is possible.
[0056]
  <Others>
  Although not shown in the figure, it is preferable to clean the surface of ice stored in the cooling coil by spraying fresh water into the heat storage tank, for example, from a sprayer as appropriate during or after the freeze-separation operation. As a result, waste water or concentrated waste water adhering to the ice surface can be washed away, and recycled water with a lower impurity concentration can be produced.
[0057]
  <Experimental example>
  Freezing and separation experiments were performed using the present invention device using salt water instead of waste water and employing a falling liquid film type ice heat storage device and a device employing a submerged ice storage device. As a result, the salinity concentration in the cooling coil adhering ice in the apparatus of the present invention was 2/3 of the salinity concentration in the cooling coil adhering ice in the apparatus employing the submerged ice heat storage device. Also from this result, it can be seen that the apparatus of the present invention makes it difficult for impurities to be taken into the production ice by the above-described washing-up of the concentrated portion with the falling wastewater, and thereby has a particularly excellent freeze separation effect.
[0058]
【The invention's effect】
  As described above, according to the present invention, waste water can be stored as ice substantially consisting of pure water, and the ice can be reused as a cold heat source or as a water source. Will be able to. In addition, it is difficult for impurities to be taken into ice during ice making, and the content of impurities in ice storage can be significantly reduced, making it easier to reuse ice-melt water and greatly improving the amount of ice making. The reuse efficiency of waste water can be remarkably increased.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a basic form of a freeze separation device according to the present invention.
FIG. 2 is a flowchart showing the freeze separation operation state.
FIG. 3 is a flow diagram showing a state of the concentrated water wastewater.
FIG. 4 is a flowchart showing the reuse water production operation state.
FIG. 5 is a flowchart showing a first applied form of the freeze separation device according to the present invention.
FIG. 6 is a time flow chart suitable for the first application mode.
FIG. 7 is a flowchart showing a second application mode of the freeze separation device according to the present invention.
FIG. 8 is a time flow chart suitable for the second application mode.
FIG. 9 is a flowchart of the power generation system.
[Explanation of symbols]
  DESCRIPTION OF SYMBOLS 1 ... Freezing separation apparatus, 2 ... Waste water tank, 3 ... Reuse water tank, 4 ... Falling liquid film type ice heat storage apparatus.

Claims

A cooling coil through which ice-making refrigerant passes is provided in the heat storage tank, a water sprinkler is provided above the cooling coil, a water storage part is provided below the cooling coil, and a water storage surface of the water storage part is separated below the cooling coil. A falling liquid film type ice storage device configured to be maintained.
A wastewater tank for collecting and storing wastewater from wastewater sources;
A reusable water tank,
During freeze-separation operation, waste water stored in the waste water tank is continuously circulated between the waste water tank and the falling liquid film type ice heat storage device, and this circulating waste water is circulated in the falling liquid film type ice heat storage device. The sprayed water is sprayed from the sprinkler, and the sprayed waste water is allowed to flow down in the form of a liquid film around the surface of the cooling coil or the ice attached to the cooling coil. While only a part of the water is icing on the surface of the cooling coil or the ice surface adhering to the cooling coil, the remaining concentrated portion is taken into the falling waste water flowing down through the icing part and washed away, and the water storage unit Configured to return the wastewater that reaches to the wastewater tank,
It is configured to discharge the concentrated waste water remaining in the waste water tank after the freeze separation operation is completed, and
During the reuse water production operation, the ice stored in the cooling coil is defrosted and the deiced water is removed without supplying the wastewater from the wastewater tank to the sprinkler and returning the wastewater from the reservoir to the wastewater tank. A freeze separation device characterized by being configured to supply to the reused water tank.

Comprising at least two of the wastewater tanks and configured to selectively supply wastewater from the wastewater supply source to the wastewater tanks;
The freeze separation operation and the reuse water production operation are configured to be performed alternately,
The wastewater tank that collects the wastewater during each freeze separation operation is switched to the wastewater tank that discharges the concentrated wastewater, and the stored wastewater of the wastewater tank that is not collecting wastewater during each freeze separation operation is transferred to the heat storage tank. The freeze separation device according to claim 1, wherein the freeze separation device is configured to supply.

Comprising at least two of the wastewater tanks and configured to selectively supply wastewater from the wastewater supply source to the wastewater tanks;
On the other hand, the falling film type ice heat storage device includes a plurality of heat storage tanks and performs the freeze separation operation using at least one heat storage tank, and at the same time, at least one of the remaining heat storage tanks is used. Configured to perform the reuse water production operation using ,
The wastewater from the wastewater supply source is collected and stored only in one of the wastewater tanks, and the stored wastewater collected in the other wastewater tank is supplied to the heat storage tank during the freeze separation operation as ice. Store,
When the storage amount of the one wastewater tank becomes a predetermined amount, the wastewater from the wastewater supply source is switched to stop collecting in the one wastewater tank and collect in the other wastewater tank, The freeze separation apparatus according to claim 1, wherein the stored wastewater of the one wastewater tank is supplied to a heat storage tank during the freeze separation operation and stored as ice.