JP4072356B2

JP4072356B2 - Oil / water separator and oil / water separator

Info

Publication number: JP4072356B2
Application number: JP2002042516A
Authority: JP
Inventors: 聰塚原; 公男齋藤
Original assignee: Hitachi Industrial Equipment Systems Co Ltd
Current assignee: Hitachi Industrial Equipment Systems Co Ltd
Priority date: 2002-02-20
Filing date: 2002-02-20
Publication date: 2008-04-09
Anticipated expiration: 2022-02-20
Also published as: JP2003236305A

Description

【０００１】
【発明の属する技術分野】
本発明は油水分離装置とその油水分離方法に関し、特に、微細気泡による浮上分離法を用いた油水分離に関するものである。
【０００２】
【従来の技術】
浮上分離法による油水分離装置として、特開平５−３１７８４７号公報に記述されるものがある。この装置では、大容量の処理槽から被処理液を汲み上げ加圧した後に加圧空気を混合溶解させ、余剰空気を除去した後に処理槽内に噴射減圧することによって、処理槽内の被処理液中に微細空気泡を発生させている。この微細空気泡と油分が付着することで、油分は浮上し、油と水分が分離する。
【０００３】
【発明が解決しようとする課題】
装置自体の設置面積は限定されることが多いから、処理槽は小型にすることが望まれる。単純に小型化すると処理槽内での循環流が強くなり、一旦、液面上まで浮上した油粒子（油分）が水の下降流に乗って処理槽底部近傍まで下降するため、油分濃度が一定値以下にはならず、結果的に油水分離性能が低下する。
【０００４】
処理槽での槽内循環流を弱くするべく処理槽を大容量とすれば油水分離性能の低下は防止できるが、被処理液に空気を溶解させるために処理槽から被処理液を汲み上げて処理槽に戻すという槽外循環の流量が処理槽容量に対して少なくなり、全体として油分濃度低下速度は遅くなり油水分離に時間がかかるようになる。また、装置が大型になる。
【０００５】
被処理液として圧縮機のドレンをみると、大気中の水分量（絶対湿度）によってその量および油分濃度が変化する。絶対湿度が高い時期にはドレン量は多いがドレン中の油分濃度は低く、絶対湿度の低い時期にはドレン量は少ないが油分濃度は高いという性質がある。
【０００６】
そこで圧縮機のドレンのような被処理液を処理するための油水分離装置では、多量で高濃度の油分を含んだ被処理液を想定して性能を設定しており、そうすると絶対湿度が高い時期では油分濃度は低いにも係わらず油水分離性能は高めに設定され、絶対湿度の低い時期にはドレン量は少ないにも係わらず処理槽は余分な大きさを持っているということになる。
【０００７】
それゆえ本発明の目的は、小型であっても高速に油水分離の処理ができる油水分離装置及び油水分離方法を提供することにある。
【０００８】
本発明の他の目的は、被処理液量やその油分濃度が変化しても高速に油水分離の処理ができる油水分離装置及び油水分離方法を提供することにある。
【０００９】
【課題を解決するための手段】
上記目的を達成する本発明油水分離装置の特徴とするところは、
処理槽に貯留した被処理液中に微細気泡を供給することによって被処理液に含まれる油分を浮上させ水と油分とを分離させる油水分離装置において、
処理槽は槽内を被処理液を貯留し油水分離が行われる分離部とこの分離部で浮上分離した油分を回収する浮上油受け部とに仕切る遮蔽板を有し、該分離部の下部から汲み出した被処理液に空気供給手段で空気を溶解させて該分離部の下部近傍に設置したノズルから噴射し、被処理液を該分離部に戻す被処理液循環配管系を有し、該被処理液循環配管系は被処理液に溶解しえない空気を除去する気泡除去手段と未処理状態の被処理液を供給する供給手段を含み、該分離部は上部に処理済の被処理液を排出し水位を調整する機能を有する排出管を接続していることにある。
【００１０】
また、上記目的を達成する本発明油水分離方法の特徴とするところは、上記油水分離装置を用い、分離部の下部から被処理液を汲み上げて分離部に戻す槽外循環を行いつつその槽外循環流路に未処理状態の被処理液を供給することを連続して行う連続処理と分離部の下部から被処理液を汲み上げて分離部に戻す槽外循環を行う期間と該槽外循環流路に未処理状態の被処理液を供給することを行う期間を交互に行う間歇処理を、未処理状態の被処理液量が多く油分濃度が低い場合に連続処理を行い、未処理状態の被処理液量が少なく油分濃度が高い場合に間歇処理を行うように、未処理状態の被処理液量及びその油分濃度に応じて切り替えることにある。
【００１１】
従って、絶対湿度が高い時期には連続処理とし、絶対湿度の低い時期には間歇処理とすることで、小型でも高速に油水分離をすることができる。
【００１２】
【発明の実施の形態】
以下、図１に示した本発明の一実施形態について説明する。
【００１３】
図１において、処理槽１１には槽内を被処理液を貯留し油水分離を行う分離部８１とこの分離部８１で浮上分離した油分を回収する浮上油受け部８３とを分離する遮蔽板１２を設けてある。処理槽１１の底部には、分離部８１と連通するように大気泡分離器１３および円管状の管路１６が設けてある。
【００１４】
処理槽１１の底に取り付けた配管３０はバルブ３６を介して循環ポンプ３１と接続し、循環ポンプの出口側配管３７は大気泡分離器１３部に設けたノズル３３に接続してある。配管３０から循環ポンプ３１を経て管路１６に至る経路は槽外循環をなす被処理液循環配管系を構成している。
【００１５】
管路１６には長さ方向に流量を均等分配する複数の開口部１７が設けてあり、開口部１７の総面積は管路１６の横断面積Ａよりも小さくしてある。管路１６は、管路長さ方向に管路断面積を順次小さくして管路内流速を一定にすると、流量分配がより均等になる。大気泡分離器１３の分離部８１側の上部には大気泡排出管１４を接続し、大気泡排出管１４は処理槽１１の高さ方向の中間部近傍から分離部８１に挿入して、その端部を被処理液の上面近傍に開口するように設けてある。大気泡分離器１３と大気泡排出管１４とで気泡除去手段を構成している。
【００１６】
配管３０側には、空気を供給する空気供給管３５をバルブ３４を介して接続してある。更に、配管３０側には被処理液供給系統を構成する供給管２３を接続してあり、供給管２３にバルブ２２を介して供給ポンプ２１を設けてある。
【００１７】
分離部８１の上部には分離部８１の上部から処理済の被処理液を排出する排出管４１を設けてあり、排出管４１は分離部８１との接続部から持上げ、その下流を分離部８１との接続部よりも低い位置まで配管してあり、その途中にバルブ４２を有している。排出管４１の最高位は、処理槽１１の遮蔽板１２の最高位より低くして位置差Ｄ１を持たせてある。従って、分離部８１内に被処理液を供給し貯留させる場合、バルブ４２を開放してあれば、被処理液は排出管４１から流出して、分離部８１における被処理液面６１は排出管４１の最高位で規制され、バルブ４２を閉止し分離槽８１内に被処理液を供給していけば、被処理液面６１は排出管４１の最高位よりも上昇していくので、排出管４１はバルブ４２の開閉で被処理液を排出し水位を調整する機能を備えていることになる。因みに、被処理液面６１の上部には油水分離で上昇した浮上油の浮上油液面６２が形成される。
【００１８】
分離部８１から排出管４１へ流入する処理済の被処理液に分離部８１を上昇中の微細気泡および油粒子が混入することを防止する仕切板１５を設け、ポケット状吸入部８２を形成している。仕切板１５の最高位は排出管４１の最高位より低くして、位置差Ｄ２を持たせている。また、仕切板１５の最高位は排出管４１の分離部８１との接続部より高くして、位置差Ｄ３を持たせている。排出管４１における被処理液の流出量と吸入部８２の入口面積で決まる吸入部８２での被処理液の下降速度が気泡の上昇速度より遅ければ、分離部８１を上昇中の微細気泡および油粒子は吸入部８２に流入して排出管４１に混入することはない。
【００１９】
浮上油受け部８３の底部には、油分を排出する油分排出管５１が設けてある。図示しないが、処理槽１１の底部から外部に配管を設け、その途中にバルブを設けてあり、分離部８１内部の液体を排出する必要がある場合にこれらを用いる。尚、被処理液は供給管２３を分離部８１の下部に接続して供給してもよい。
【００２０】
次にその動作を説明する。
先ず、絶対湿度が高い時期に行う連続処理について説明する。
準備として、バルブ４２は開放状態として処理槽１１の分離部８１を清水または処理済の被処理液液を充填し、被処理液面６１を排出管４１の最高位に一致したら、循環ポンプ３１を運転する。この時、バルブ２２は閉止し、供給ポンプ２１は停止している。バルブ３４，３６は開放状態としてあり、清水または処理済の被処理液が配管３０を流れることによって、空気供給管３５側が負圧となり、溶解用空気が空気供給管３５から流入する。流入した空気は配管３０内を流れる液体に混入し溶解する。溶解しなかった余剰空気はそのままの状態で、空気の溶解した液体と一緒にノズル３３から大気泡分離器１３内に吐出させる。ノズル３３から吐出することで圧力の加わっていた液体、および空気は減圧し、水に溶解していた空気は微細気泡となり、溶解していなかった空気は大気泡となる。大気泡分離器１３では、気泡径が大きくなるほど液中上昇速度が速い特性を気泡が持っているため、大気泡は大気泡分離器１３の上部へ溜り、大気泡排出管１４から分離部８１の上方部へ排出される。
【００２１】
従って、大気泡分離器１３の出口に続く管路１６の開口部１７からは微細気泡のみを含む清水または処理済の被処理液が分離部８１に噴出する。前記開口部から噴出した清水または処理済の被処理液は、分離部８１に存在する清水または処理済の被処理液と混合し、減速しながら流れる。その流れは図２に示すように槽内循環流を形成し、管路１６の周囲には、開口部１７からの噴射流と配管３０に向かう下降流で強い循環流が形成されている。分離部８１上部では、微細気泡の上昇に伴い弱い循環流が形成されている。分離部８１の下部で強い循環流が分離部８１上部への循環流と一体になると、微細気泡および油粒子が循環流から分離できずに、油水分離性能が低下する。このため、分離部８１内部に管路１６を突き出し、管路１６の長さ方向に流量を均等分配することによって局部的に循環流が強くなることを防止して、微細気泡の上昇による分離部８１の上部に向う循環流を維持するようにしている。
【００２２】
この運転状態を保ちながら、バルブ２２を開放し供給ポンプ２１を駆動して被処理液供給系統を運転し、被処理液循環系統を循環している清水または処理済の被処理液に未処理状態の被処理液を混合させる。
【００２３】
すると、開口部１７から微細気泡と共に油粒子が噴射され、油分と微細気泡が付着し浮上し、油分が分離する。
【００２４】
分離部８１の上部にある吸入部８２では、被処理液供給系統から供給された未処理状態の被処理液相当分の処理済の被処理液を微細気泡の上昇速度よりも遅い速度で吸込んで排出管４１から排出する。
【００２５】
循環ポンプ３１出口での圧力は、所要動力を少なくすることと微細気泡の直径を小さくすることを考慮すると０．３〜０．８ＭＰａ程度が好ましい。溶解空気量が圧力に比例することを考慮すると、循環水流量は被処理液供給系統から供給された未処理状態の被処理液量の３０〜１００倍で、未処理状態の被処理液は循環水によって３０〜１００倍に希釈されるので、分離部８１に供給される被処理液の油分は低濃度である。
【００２６】
この連続処理では、被処理液循環系統を通過した被処理液中の油分を分離部８１に噴出して上昇する時間内に油水分離処理を行う。即ち、被処理液供給系統から供給された未処理状態の被処理液量相当の処理済みの被処理液を分離部８１の上部から排出管４１を通して流出させているので、槽外循環だけをしている場合よりも油水分離の障害となる下降流は少なくなり、分離部を小型なものとしても、微細気泡による分離性能を維持できる。
【００２７】
分離部８１上部の浮上油は連続運転中に排出管４１の途中に設けたバルブ４２を一時的に閉じると、分離部８１内部の被処理液面６１および浮上油液面６２が上昇し、遮蔽板高さに近くなると、大気泡排出管１４から排出される空気泡による被処理液面６１の波立ち利用して、浮上油を遮蔽板１２をオーバフローさせて浮上油受け部８３へ流下させる。浮上油が減ったら、バルブ４２をゆっくり開けて、排出管４１から被処理液を排出して被処理液面６１を下げて連続処理を継続する。
【００２８】
次に、絶対湿度の低い時期に行う間歇処理について説明する。
まず、準備として連続処理と同様に、分離部８１に清水または処理済の被処理液を充満させた状態で循環ポンプ３１を運転する。バルブ３６、バルブ３４は開放状態にしてあり、溶解用空気が空気供給管３５から流入する。この運転を暫く行うと分離部８１における被処理液の温度が上昇し、密度が小さくなる。尚、分離部８１における被処理液の温度を上昇させるために分離部８１に加熱手段を配設しておいてもよい。
【００２９】
そこで、被処理液循環系統における循環ポンプ３１の運転を停止し、被処理液供給系統のバルブ２２を開放状態にして供給ポンプ２１を運転して、未処理状態の被処理液を供給する。被処理液は、配管３０および配管３７、ノズル３３、管路１６、開口部１７から分離部８１に流入する。被処理液は分離部８１内の清水または処理済の被処理液よりも温度が低く密度が大きいために分離部８１の底部に溜って行き、密度が小さい処理済の油分濃度の低い被処理液は分離部８１の上部に押し上げられた形となって、吸入部８２から排出管４１，バルブ４２を経由して排出される。例えば、仕切板１５上端から分離部８１の底部までにおける容積が４０Ｌ，清水または処理済の被処理液温度が３２０Ｋ、未処理状態の被処理液温度が２８３Ｋ、未処理状態の被処理液の供給を２０Ｌ／ｈで行うと、処理済の被処理液のみを３０Ｌ以上排出可能である。
【００３０】
処理済の被処理液のみの排出が済んだら、バルブ２２とバルブ４２を閉状態にして未処理状態の被処理液の供給を止めて、循環ポンプ３１による槽外循環を実施する。分離部８１内の流動状態は図２と同様である。バルブ４２は閉止してあり、分離部の被処理液中に気泡が存在することにより、被処理液面６１は排出管４１の最高位置よりも高くなる。この状態で分離部８１内部の被処理液面６１上側に浮上油が溜まるが、浮上油液面６２よりも遮蔽板１２を高く配置してあり、循環中に浮上油が浮上油受け部８３へ遮蔽板１２からオーバフローすることはない。槽外循環中に分離部下方の油分は微細気泡によって上昇し、油水分離する。浮上油分離法では油分が高濃度であるほど分離性能は良いので、中間濃度以下までは高速に分離できる。低濃度域は連続処理に近い分離性能を有する。
【００３１】
本発明者らの観察によれば、槽外循環の前半５０％の時間で未処理状態の被処理液の油分濃度は中間濃度以下の１／５程度に低下し、後半５０％の時間で中間濃度以下の油分濃度からさらにその１／５程度の低濃度（連続処理での目標濃度）に低下することを確認している。前後半で低減する比率は同程度であるが、絶対値でみれば前半に大半の油分が分離されていることになる。
【００３２】
分離部８１における被処理液が目標とする濃度に低下したら、循環ポンプ３１を停止し、バルブ２２とバルブ４２を開放させ、供給ポンプ２１を運転して未処理状態の被処理液を槽外循環流路に供給する。この期間中に分離部８１の処理済の被処理液は供給した未処理状態の被処理液と同量だけ排出管４１から排出される。
【００３３】
被処理液の供給と循環のために供給ポンプ２１の運転と停止を交互に繰り返し、浮上油液面６２と被処理液面６１との差が大きくなったら、即ち分離部８１上部に浮上油が溜まったら、供給ポンプ２１の運転中に排出管４１のバルブ４２を閉止状態にし、被処理液面６１が遮蔽板１２と同一高さになることによって浮上油を遮蔽板１２からオーバフローさせ、浮上油受け部８３へ排出する。
【００３４】
通常のスクリュー圧縮機では一週間の連続運転により浮上油が約１ｍｍ溜まるので、浮上油の排出は一週間に１回程度行う。この排出時期は運転時間で決定するだけでなく、浮上油量、浮上油厚さを測定することによっても決定できる。
【００３５】
この間歇処理では、分離部８１内に清水または処理済の被処理液液と約５０％の未処理状態にある被処理液を混合して油水分離処理し、油分は高濃度から低濃度まで短時間で下げることになる。
【００３６】
図３は、一般的なスクリュー圧縮機のドレン流量と油分濃度の関係を示している。夏季に相当する大気中の水分量が多い時期にはドレン流量が多く、油分濃度は低い。冬季に相当する大気中の水分量が少ない時にはドレン流量が少なく、油分濃度は高い。そこで前記２つの運転方法の特徴を生かして、ドレン流量が多く、油分濃度が低い場合には連続処理を行い、ドレン流量が少なく、油分濃度が高い場合には間歇運転を行うことにより、小型で高速処理可能な油水分離装置を構成できる。
【００３７】
間歇処理運転は、槽外循環期間と被処理液供給期間の長さを異ならせた複数のパターンを用意して、中間濃度域の余裕を広くすることも可能である。
【００３８】
図３の一点鎖線は、２パターンに分ける濃度域を示している。高濃度の第Ｉ領域、中濃度の第II領域に分けて、第Ｉ領域では槽外循環期間と被処理液供給期間を共に長い第一運転パターンとし、第II領域では槽外循環期間と被処理液供給期間を共に第Ｉ領域より短い第二運転パターンとしている。冬季には第一運転パターンの間歇処理を行い、春秋には第二運転パターンの間歇処理を行う。こうすることで年中、如何なる状態の被処理液であっても1台の装置で対応できる。なお、槽外循環期間のみを変化させることによっても同様に対応できる。
【００３９】
これらの運転パターン選択にはドレン流量または油分濃度の情報が必要である。油分濃度は短時間で計測する方法が無いので、運転パターン選択にはドレン流量の情報を用いる。ドレン流量は大気中の水分量、圧縮機吐出空気圧力、空気冷却器出口温度、凝縮水補集効率から計算できる、従って、大気温度と大気湿度を計測する方法がある。一方、通常は圧縮機からのドレンを一旦溜めるタンクを設けており、この中に液面計を取付け、液面の変化からドレン流量を算出する方法がある。また、大気温度のみを測定して、大気湿度１００％としたドレン最大流量を計算し、この値を制御に用いることも可能である。実際にはこれらの方法を単独もしくは組合わせて制御に用いる。
【００４０】
これらのパターンや運転モードの切り替えは図示していない制御装置にシーケンスプログラムとして用意しておき、油分濃度を確認するための大気中の湿度などの上述した各項目の計測結果やカレンダーなどに基づいて適宜に切り替えるようにしておくことができる。
【００４１】
図４は、上記油水分離装置を実用化した場合の高さ方向の配置を示している。処理槽１１は、処理済の被処理液および浮上油を重力で排出するので上方に設置している。処理槽１１の下側空間を有効利用するために供給ポンプ２１、循環ポンプ３１を処理槽１１の下に配置し、その横に浮上油タンク７１を設置し、これらを配管で接続している。そしてこれら全体を筐体内に収納している。このようにすることで、設置面積の一層の縮小化を図ることができる。
【００４２】
【発明の効果】
以上説明したように、本発明によれば小型であっても高速に油水分離の処理ができる油水分離装置が得られる。
【００４３】
また、本発明によれば、被処理液量やその油分濃度が変化しても高速に油水分離の処理ができる。
【図面の簡単な説明】
【図１】本発明の一実施形態になる油水分離装置を示す図である。
【図２】図１に示した処理槽の分離部での被処理液の流動状態を示す図である。
【図３】圧縮機におけるドレンの流量と油分濃度の関係を示す図である。
【図４】本発明になる油水分離装置の高さ方向の配置を示す図である。
【符号の説明】
１１…処理槽
１２…遮蔽板
１５…仕切板
１６…管路
１３…大気泡分離器
１４…大気泡排出管
１７…開口部
２１…供給ポンプ
２３…被処理液供給管
３１…循環ポンプ
３３…ノズル
４１…排出管
４２…バルブ
５１…油分排出管
６１…被処理液面
６２…浮上油液面
８１…分離部
８２…ポケット状吸入部
８３…浮上油受け部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oil / water separator and an oil / water separation method, and more particularly, to an oil / water separation using a floating separation method using fine bubbles.
[0002]
[Prior art]
As an oil-water separator by the floating separation method, there is one described in JP-A-5-317847. In this apparatus, the liquid to be treated in the treatment tank is obtained by pumping up the liquid to be treated from a large-capacity treatment tank, pressurizing and mixing the pressurized air, removing excess air, and then depressurizing the liquid into the treatment tank. Fine air bubbles are generated inside. By attaching the fine air bubbles and the oil component, the oil component floats and the oil and moisture are separated.
[0003]
[Problems to be solved by the invention]
Since the installation area of the apparatus itself is often limited, it is desirable to make the treatment tank small. If the size is simply reduced, the circulating flow in the treatment tank becomes stronger, and once the oil particles (oil) that have floated up to the liquid level descend on the water flow down to the vicinity of the bottom of the treatment tank, the oil concentration is constant. The oil / water separation performance is lowered as a result.
[0004]
If the capacity of the treatment tank is increased to weaken the circulating flow in the treatment tank, the oil / water separation performance can be prevented from decreasing, but the treatment liquid is pumped up from the treatment tank to dissolve the treatment liquid. The flow rate of the circulation outside the tank, which is returned to the tank, decreases with respect to the capacity of the processing tank. As a whole, the oil concentration lowering rate becomes slow, and it takes time to separate the oil and water. In addition, the apparatus becomes large.
[0005]
When the drain of the compressor is seen as the liquid to be treated, the amount and oil concentration change depending on the amount of moisture (absolute humidity) in the atmosphere. When the absolute humidity is high, the drain amount is large, but the oil concentration in the drain is low, and when the absolute humidity is low, the drain amount is small but the oil concentration is high.
[0006]
Therefore, the oil / water separator for treating the liquid to be treated, such as the drain of the compressor, sets the performance assuming that the liquid to be treated contains a large amount of high-concentration oil, and then the absolute humidity is high. Then, although the oil concentration is low, the oil / water separation performance is set to be high, and at the time of low absolute humidity, the treatment tank has an extra size even though the drain amount is small.
[0007]
Therefore, an object of the present invention is to provide an oil / water separation apparatus and an oil / water separation method capable of performing oil / water separation at high speed even if it is small.
[0008]
Another object of the present invention is to provide an oil / water separation apparatus and an oil / water separation method capable of performing oil / water separation at high speed even if the amount of liquid to be treated and its oil concentration change.
[0009]
[Means for Solving the Problems]
The feature of the oil-water separator of the present invention that achieves the above object is as follows.
In the oil-water separator for separating the water and the oil component by floating the oil contained in the liquid to be treated by supplying fine bubbles into the liquid to be treated stored in the treatment tank,
The treatment tank has a shielding plate that partitions the treatment liquid in the tank and separates the oil / water separation and a floating oil receiving part that collects the oil floating and separated in the separation part, from the lower part of the separation part the liquid to be treated was pumped by dissolving air in the air supply means is ejected from a nozzle installed near the lower portion of the separating portion has a liquid to be treated circulates piping system for returning the liquid to be treated the separation unit,該被The processing liquid circulation piping system includes a bubble removing means for removing air that cannot be dissolved in the liquid to be processed and a supply means for supplying the liquid to be processed in an unprocessed state. It is that a discharge pipe having a function of discharging and adjusting the water level is connected.
[0010]
In addition, the oil / water separation method of the present invention that achieves the above object is characterized by using the oil / water separator and pumping the liquid to be treated from the lower part of the separation part and returning it to the separation part while performing circulation outside the tank. Continuous processing for continuously supplying the untreated liquid to the circulation flow path, a period for performing the external circulation for pumping the liquid to be treated from the lower part of the separation section and returning it to the separation section, and the circulation flow outside the tank Intermittent treatment in which the period for supplying untreated liquid to the road is alternately performed is performed continuously when the amount of untreated liquid is large and the oil concentration is low. The purpose is to switch according to the amount of liquid to be treated and its oil concentration so that intermittent treatment is performed when the amount of treatment liquid is small and the oil concentration is high .
[0011]
Therefore, by performing continuous treatment when the absolute humidity is high and intermittent treatment when the absolute humidity is low, oil and water can be separated at high speed even with a small size.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention shown in FIG. 1 will be described.
[0013]
In FIG. 1, in a treatment tank 11, a shielding plate 12 that separates a separation unit 81 that stores a liquid to be treated and separates oil and water and a floating oil receiving unit 83 that collects oil separated and floated by the separation unit 81. Is provided. A large bubble separator 13 and a circular pipe line 16 are provided at the bottom of the treatment tank 11 so as to communicate with the separation unit 81.
[0014]
A pipe 30 attached to the bottom of the treatment tank 11 is connected to a circulation pump 31 via a valve 36, and an outlet side pipe 37 of the circulation pump is connected to a nozzle 33 provided in the large bubble separator 13 part. A path from the pipe 30 to the pipe line 16 via the circulation pump 31 constitutes a liquid circulation pipe system to be treated that circulates outside the tank.
[0015]
The pipe 16 is provided with a plurality of openings 17 that equally distribute the flow rate in the length direction, and the total area of the openings 17 is smaller than the cross-sectional area A of the pipe 16. In the pipe line 16, when the pipe cross-sectional area is sequentially reduced in the pipe length direction so that the flow velocity in the pipe line becomes constant, the flow distribution becomes more uniform. A large bubble discharge pipe 14 is connected to the upper part of the large bubble separator 13 on the separation part 81 side, and the large bubble discharge pipe 14 is inserted into the separation part 81 from the vicinity of the intermediate part in the height direction of the treatment tank 11, The end portion is provided so as to open near the upper surface of the liquid to be processed. The large bubble separator 13 and the large bubble discharge pipe 14 constitute bubble removing means.
[0016]
An air supply pipe 35 for supplying air is connected to the pipe 30 via a valve 34. Further, a supply pipe 23 constituting a liquid supply system to be treated is connected to the pipe 30 side, and a supply pump 21 is provided on the supply pipe 23 via a valve 22.
[0017]
A discharge pipe 41 that discharges the processed liquid from the top of the separation section 81 is provided above the separation section 81, and the discharge pipe 41 is lifted from a connection section with the separation section 81, and the downstream thereof is separated by the separation section 81. The pipe is piped to a position lower than the connecting portion with the valve 42 in the middle thereof. The highest position of the discharge pipe 41 is set lower than the highest position of the shielding plate 12 of the processing tank 11 so as to have a positional difference D1. Therefore, when supplying and storing the liquid to be processed in the separation unit 81, if the valve 42 is opened, the liquid to be processed flows out from the discharge pipe 41, and the liquid surface 61 to be processed in the separation unit 81 is discharged from the discharge pipe. If the valve 42 is closed and the liquid to be treated is supplied into the separation tank 81, the liquid surface 61 to be treated rises above the highest level of the discharge pipe 41. 41 has a function of discharging the liquid to be treated and adjusting the water level by opening and closing the valve 42. Incidentally, a floating oil liquid level 62 of the floating oil that has risen by the oil-water separation is formed on the top of the liquid surface 61 to be treated.
[0018]
A partition plate 15 is provided to prevent the fine bubbles and oil particles rising in the separation unit 81 from entering the treated liquid flowing into the discharge pipe 41 from the separation unit 81, thereby forming a pocket-shaped suction unit 82. ing. The highest position of the partition plate 15 is set lower than the highest position of the discharge pipe 41 so as to have a positional difference D2. Further, the highest position of the partition plate 15 is set higher than the connection portion of the discharge pipe 41 with the separation portion 81 so as to have a positional difference D3. If the lowering speed of the liquid to be treated in the suction part 82 determined by the outflow amount of the liquid to be treated in the discharge pipe 41 and the inlet area of the suction part 82 is slower than the rising speed of the bubbles, the fine bubbles and oil rising in the separation part 81 The particles do not flow into the suction part 82 and enter the discharge pipe 41.
[0019]
An oil discharge pipe 51 that discharges oil is provided at the bottom of the floating oil receiver 83. Although not shown in the drawing, piping is provided outside from the bottom of the processing tank 11 and a valve is provided in the middle thereof, and these are used when it is necessary to discharge the liquid inside the separation unit 81. The liquid to be treated may be supplied by connecting the supply pipe 23 to the lower part of the separation unit 81.
[0020]
Next, the operation will be described.
First, continuous processing performed at a time when the absolute humidity is high will be described.
As a preparation, the valve 42 is opened and the separation unit 81 of the treatment tank 11 is filled with clean water or a treated liquid to be treated. When the liquid surface 61 to be treated coincides with the highest level of the discharge pipe 41, the circulation pump 31 is turned on. drive. At this time, the valve 22 is closed and the supply pump 21 is stopped. The valves 34 and 36 are in an open state, and when clean water or processed liquid to be processed flows through the pipe 30, the air supply pipe 35 side becomes negative pressure, and dissolution air flows from the air supply pipe 35. The inflowing air is mixed and dissolved in the liquid flowing in the pipe 30. The excess air that has not been dissolved is discharged as it is into the large bubble separator 13 from the nozzle 33 together with the liquid in which the air is dissolved. The liquid and air that have been pressurized by discharging from the nozzle 33 are decompressed, the air dissolved in the water becomes fine bubbles, and the air that has not been dissolved becomes large bubbles. In the large bubble separator 13, since the bubbles have a characteristic that the rising speed in the liquid increases as the bubble diameter increases, the large bubbles accumulate on the upper portion of the large bubble separator 13, and from the large bubble discharge pipe 14 to the separation unit 81. It is discharged to the upper part.
[0021]
Therefore, fresh water or treated liquid containing only fine bubbles is ejected from the opening 17 of the pipe line 16 following the outlet of the large bubble separator 13 to the separation unit 81. The fresh water or processed liquid to be processed ejected from the opening is mixed with the fresh water or processed liquid to be processed existing in the separation unit 81 and flows while decelerating. The flow forms a circulation flow in the tank as shown in FIG. 2, and a strong circulation flow is formed around the pipe line 16 by the jet flow from the opening 17 and the downward flow toward the pipe 30. In the upper part of the separation part 81, a weak circulation flow is formed as the fine bubbles rise. If a strong circulation flow is integrated with the circulation flow to the upper part of the separation unit 81 at the lower part of the separation unit 81, the fine bubbles and oil particles cannot be separated from the circulation flow, and the oil / water separation performance is lowered. For this reason, the pipe line 16 protrudes into the separation part 81 and the flow rate is evenly distributed in the length direction of the pipe line 16 to prevent the circulation flow from becoming strong locally. The circulating flow toward the upper part of 81 is maintained.
[0022]
While maintaining this operation state, the valve 22 is opened and the supply pump 21 is driven to operate the liquid supply system to be processed, so that the fresh water or the processed liquid to be processed circulating in the liquid circulation system to be processed is not yet processed. The liquid to be treated is mixed.
[0023]
Then, oil particles are jetted from the opening 17 together with the fine bubbles, the oil and fine bubbles adhere and float, and the oil is separated.
[0024]
In the suction part 82 at the upper part of the separation part 81, the processed liquid to be processed corresponding to the unprocessed liquid supplied from the processed liquid supply system is sucked at a speed slower than the rising speed of the fine bubbles. It discharges from the discharge pipe 41.
[0025]
The pressure at the outlet of the circulation pump 31 is preferably about 0.3 to 0.8 MPa in consideration of reducing the required power and reducing the diameter of the fine bubbles. Considering that the amount of dissolved air is proportional to the pressure, the circulating water flow rate is 30 to 100 times the amount of untreated liquid to be treated supplied from the untreated liquid supply system, and the untreated liquid is circulated. Since it is diluted 30 to 100 times with water, the oil content of the liquid to be treated supplied to the separation unit 81 has a low concentration.
[0026]
In this continuous treatment, the oil / water separation treatment is performed within the time during which the oil in the liquid to be treated that has passed through the liquid circulation system to be treated is ejected to the separation unit 81 and rises. That is, since the treated liquid corresponding to the untreated liquid amount supplied from the treated liquid supply system is discharged from the upper part of the separation unit 81 through the discharge pipe 41, only the circulation outside the tank is performed. Therefore, the downward flow that becomes an obstacle to oil-water separation is less than in the case where the separation is performed, and the separation performance by the fine bubbles can be maintained even if the separation portion is made small.
[0027]
When the valve 42 provided in the middle of the discharge pipe 41 is temporarily closed during continuous operation, the floating oil on the upper part of the separation unit 81 rises, and the liquid surface 61 to be treated and the floating oil liquid level 62 inside the separation unit 81 rise. When the plate height is approached, the floating oil is caused to overflow the shielding plate 12 and flow down to the floating oil receiving portion 83 by using the wave of the liquid surface 61 to be treated by the air bubbles discharged from the large bubble discharge pipe 14. When the floating oil decreases, the valve 42 is opened slowly, the liquid to be processed is discharged from the discharge pipe 41, the liquid surface 61 to be processed is lowered, and the continuous processing is continued.
[0028]
Next, the intermittent process performed at a time when the absolute humidity is low will be described.
First, as in preparation, as in the case of continuous processing, the circulation pump 31 is operated in a state where the separation unit 81 is filled with fresh water or a processed liquid to be processed. The valve 36 and the valve 34 are in an open state, and dissolution air flows from the air supply pipe 35. If this operation is performed for a while, the temperature of the liquid to be treated in the separation unit 81 increases and the density decreases. In order to raise the temperature of the liquid to be treated in the separation unit 81, a heating unit may be provided in the separation unit 81.
[0029]
Therefore, the operation of the circulation pump 31 in the processing liquid circulation system is stopped, the valve 22 of the processing liquid supply system is opened, and the supply pump 21 is operated to supply the processing liquid in the unprocessed state. The liquid to be processed flows into the separation unit 81 from the pipe 30 and the pipe 37, the nozzle 33, the pipe line 16, and the opening 17. Since the liquid to be processed has a lower temperature and a higher density than the fresh water or the processed liquid to be processed in the separation unit 81, the liquid to be processed accumulates at the bottom of the separation unit 81, and the processed liquid with a low processed and low oil concentration. Is pushed up to the top of the separation part 81 and discharged from the suction part 82 via the discharge pipe 41 and the valve 42. For example, the volume from the upper end of the partition plate 15 to the bottom of the separation unit 81 is 40 L, the temperature of fresh water or treated liquid to be treated is 320 K, the temperature of untreated liquid to be treated is 283 K, and the untreated liquid to be treated is supplied. Is performed at 20 L / h, only 30 L or more of the processed liquid can be discharged.
[0030]
When only the processed liquid to be processed is discharged, the valve 22 and the valve 42 are closed to stop the supply of the unprocessed liquid to be processed, and the circulation pump 31 performs circulation outside the tank. The flow state in the separation unit 81 is the same as that in FIG. The valve 42 is closed, and the liquid surface 61 to be processed becomes higher than the highest position of the discharge pipe 41 due to the presence of bubbles in the liquid to be processed in the separation section. In this state, the floating oil accumulates above the liquid surface 61 to be treated inside the separation unit 81, but the shielding plate 12 is disposed higher than the floating oil liquid surface 62, and the floating oil flows to the floating oil receiving unit 83 during circulation. There is no overflow from the shielding plate 12. During circulation outside the tank, the oil content below the separation part rises due to fine bubbles and separates oil and water. In the floating oil separation method, the higher the oil content, the better the separation performance. The low concentration region has separation performance close to continuous processing.
[0031]
According to the observation by the present inventors, the oil concentration of the liquid to be treated in the untreated state decreases to about 1/5 of the intermediate concentration or less in the first half 50% of the circulation outside the tank, and intermediate in the second half 50% of the time. It has been confirmed that the oil concentration is lower than the concentration, and further reduced to a low concentration of about 1/5 (the target concentration in the continuous treatment). The ratio of reduction in the first half is about the same, but in terms of absolute value, most of the oil is separated in the first half.
[0032]
When the liquid to be treated in the separation unit 81 decreases to a target concentration, the circulation pump 31 is stopped, the valves 22 and 42 are opened, and the supply pump 21 is operated to circulate the liquid to be treated in an untreated state outside the tank. Supply to the flow path. During this period, the processed liquid to be processed in the separation unit 81 is discharged from the discharge pipe 41 by the same amount as the supplied unprocessed liquid to be processed.
[0033]
The supply pump 21 is repeatedly operated and stopped alternately for supplying and circulating the liquid to be processed, and when the difference between the floating oil liquid level 62 and the liquid surface 61 to be processed increases, that is, the floating oil is formed above the separation unit 81. If accumulated, the valve 42 of the discharge pipe 41 is closed during the operation of the supply pump 21, and the surface of the liquid to be treated 61 is flush with the shielding plate 12, thereby causing the floating oil to overflow from the shielding plate 12. It is discharged to the receiving part 83.
[0034]
In a normal screw compressor, about 1 mm of floating oil is accumulated by continuous operation for one week, so that the floating oil is discharged about once a week. This discharge time can be determined not only by the operation time but also by measuring the amount of floating oil and the thickness of the floating oil.
[0035]
In this intermittent treatment, clean water or a treated liquid to be treated and a liquid to be treated of about 50% in an untreated state are mixed in the separation unit 81 to perform an oil / water separation treatment, and the oil content is reduced from a high concentration to a low concentration. It will be lowered in time.
[0036]
FIG. 3 shows the relationship between the drain flow rate and oil concentration of a general screw compressor. The drain flow is high and the oil concentration is low when the amount of moisture in the atmosphere is high during the summer. When the amount of water in the atmosphere corresponding to winter is small, the drain flow rate is small and the oil concentration is high. Therefore, by taking advantage of the characteristics of the two operation methods, a continuous treatment is performed when the drain flow rate is high and the oil concentration is low, and intermittent operation is performed when the drain flow rate is low and the oil concentration is high. An oil / water separator capable of high-speed processing can be configured.
[0037]
In the intermittent treatment operation, it is possible to prepare a plurality of patterns with different lengths of the circulation period outside the tank and the liquid supply period to be treated to widen the margin of the intermediate concentration range.
[0038]
A one-dot chain line in FIG. 3 indicates a density range divided into two patterns. It is divided into a high-concentration I region and a medium-concentration II region. In the I region, both the external circulation period and the liquid supply period to be treated are long first operation patterns. The treatment liquid supply period is a second operation pattern shorter than the I region. In winter, the first operation pattern is intermittently processed, and in spring and autumn, the second operation pattern is intermittently processed. In this way, the liquid to be processed in any state can be handled with a single device throughout the year. In addition, it can respond similarly also by changing only an outside tank circulation period.
[0039]
Information on the drain flow rate or oil concentration is necessary for selecting these operation patterns. Since there is no method for measuring the oil concentration in a short time, information on the drain flow rate is used for selecting an operation pattern. The drain flow rate can be calculated from the amount of moisture in the atmosphere, the compressor discharge air pressure, the air cooler outlet temperature, and the condensed water collection efficiency. Therefore, there is a method for measuring the atmospheric temperature and atmospheric humidity. On the other hand, there is usually a method in which a tank for temporarily storing the drain from the compressor is provided, and a liquid level gauge is attached therein, and the drain flow rate is calculated from the change in the liquid level. It is also possible to measure only the atmospheric temperature, calculate the maximum drain flow rate with an atmospheric humidity of 100%, and use this value for control. In practice, these methods are used alone or in combination for control.
[0040]
These patterns and operation mode switching are prepared as a sequence program in a control device (not shown), and based on the measurement results of the above-mentioned items such as atmospheric humidity for checking the oil concentration, a calendar, and the like. Switching can be made as appropriate.
[0041]
FIG. 4 shows the arrangement in the height direction when the oil-water separator is put into practical use. The processing tank 11 is installed upward because the processed liquid to be processed and the floating oil are discharged by gravity. In order to effectively use the lower space of the processing tank 11, a supply pump 21 and a circulation pump 31 are arranged below the processing tank 11, and a floating oil tank 71 is installed beside them, and these are connected by piping. These are all housed in a housing. By doing in this way, the installation area can be further reduced.
[0042]
【The invention's effect】
As described above, according to the present invention, an oil-water separator that can perform oil-water separation at high speed even if it is small is obtained.
[0043]
Further, according to the present invention, even when the amount of liquid to be treated and its oil concentration change, oil-water separation treatment can be performed at high speed.
[Brief description of the drawings]
FIG. 1 is a diagram showing an oil-water separator according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a flow state of a liquid to be processed in a separation unit of the processing tank illustrated in FIG.
FIG. 3 is a diagram showing the relationship between the drain flow rate and the oil concentration in the compressor.
FIG. 4 is a view showing the arrangement in the height direction of the oil / water separator according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Processing tank 12 ... Shielding plate 15 ... Partition plate 16 ... Pipe 13 ... Large bubble separator 14 ... Large bubble discharge pipe 17 ... Opening part 21 ... Supply pump 23 ... To-be-processed liquid supply pipe 31 ... Circulation pump 33 ... Nozzle DESCRIPTION OF SYMBOLS 41 ... Drain pipe 42 ... Valve 51 ... Oil content discharge pipe 61 ... Liquid surface to be treated 62 ... Floating oil liquid surface 81 ... Separating part 82 ... Pocket-like suction part 83 ... Floating oil receiving part

Claims

処理槽に貯留した被処理液中に微細気泡を供給することによって被処理液に含まれる油分を浮上させ水と油分とを分離させる油水分離装置において、
処理槽は槽内を被処理液を貯留し油水分離が行われる分離部とこの分離部で浮上分離した油分を回収する浮上油受け部とに仕切る遮蔽板を有し、該分離部の下部から汲み出した被処理液に空気供給手段で空気を溶解させて該分離部の下部近傍に設置したノズルから噴射し、被処理液を該分離部に戻す被処理液循環配管系を有し、該被処理液循環配管系は被処理液に溶解しえない空気を除去する気泡除去手段と未処理状態の被処理液を供給する供給手段を含み、該分離部は上部に処理済の被処理液を排出し水位を調整する機能を有する排出管を接続していることを特徴とする油水分離装置。In the oil-water separator for separating the water and the oil component by floating the oil contained in the liquid to be treated by supplying fine bubbles into the liquid to be treated stored in the treatment tank,
The treatment tank has a shielding plate that partitions the treatment liquid in the tank and separates the oil / water separation and a floating oil receiving part that collects the oil floating and separated in the separation part, from the lower part of the separation part the liquid to be treated was pumped by dissolving air in the air supply means is ejected from a nozzle installed near the lower portion of the separating portion has a liquid to be treated circulates piping system for returning the liquid to be treated the separation unit,該被The processing liquid circulation piping system includes a bubble removing means for removing air that cannot be dissolved in the liquid to be processed and a supply means for supplying the liquid to be processed in an unprocessed state. An oil-water separator having a discharge pipe having a function of discharging and adjusting a water level is connected.

上記請求項１に記載の油水分離装置において、該被処理液循環配管系は該分離部の下部から被処理液をバルブ（３６）を介して汲み出し、該供給手段は未処理状態の被処理液をバルブ（２２）を介して混合させ、該排出管はバルブ（４２）を介して該分離部の上部から被処理液を排出することを特徴とする油水分離装置。2. The oil / water separation apparatus according to claim 1, wherein the processing liquid circulation piping system pumps the processing liquid from the lower part of the separation section through a valve (36) , and the supply means is an unprocessed processing liquid. Is mixed through a valve (22) , and the discharge pipe discharges the liquid to be treated from the upper part of the separation section through the valve (42) .

上記請求項１に記載の油水分離装置において、該排出管の最高位は該遮蔽板の最高位より低くしてあることを特徴とする油水分離装置。 The oil-water separator according to claim 1, wherein the highest level of the discharge pipe is lower than the highest level of the shielding plate.

上記請求項１に記載の油水分離装置において、該分離部への該排出管の接続部は仕切板で形成するポケット状吸入部に設けてあり、該仕切板の最高位は該排出管の最高位より低くしてあることを特徴とする油水分離装置。 In the oil-water separator according to claim 1, the connection part of the discharge pipe to the separation part is provided in a pocket-like suction part formed by a partition plate, and the highest position of the partition plate is the highest of the discharge pipe. An oil-water separator characterized by being lower than the position.

上記請求項１に記載の油水分離装置において、該被処理液循環配管系は該分離部の下部に設けられた管路を含み、該管路は複数の開口部を有しており、該各開口部においてノズルから噴射した被処理液を該分離部に戻すことを特徴とする油水分離装置。 In the oil / water separator according to claim 1, the liquid circulation piping system to be treated includes a pipe provided at a lower part of the separation part, and the pipe has a plurality of openings, An oil / water separator characterized in that the liquid to be treated sprayed from the nozzle in the opening is returned to the separator.

上記請求項１に記載の油水分離装置を用い、分離部の下部から被処理液を汲み上げて分離部に戻す槽外循環を行いつつその槽外循環流路に未処理状態の被処理液を供給することを連続して行う連続処理と分離部の下部から被処理液を汲み上げて分離部に戻す槽外循環を行う期間と該槽外循環流路に未処理状態の被処理液を供給することを行う期間を交互に行う間歇処理を、未処理状態の被処理液量が多く油分濃度が低い場合に連続処理を行い、未処理状態の被処理液量が少なく油分濃度が高い場合に間歇処理を行うように、未処理状態の被処理液量及びその油分濃度に応じて切り替えることを特徴とする油水分離方法。Using the oil / water separator according to claim 1, the untreated liquid is supplied to the outside circulation flow path while performing the outside circulation of the treated liquid that is pumped up from the lower part of the separation unit and returned to the separation unit. Continuous processing to be performed, a period for performing circulation outside the tank that pumps the liquid to be treated from the lower part of the separation unit and returns it to the separation unit, and supplying the liquid to be treated in an untreated state to the circulation path outside the tank The intermittent treatment is performed alternately when the amount of untreated liquid is large and the oil concentration is low.The intermittent treatment is performed when the untreated liquid amount is low and the oil concentration is high. The oil-water separation method is characterized in that switching is performed according to the amount of liquid to be treated and its oil concentration so as to perform .