JP4139597B2

JP4139597B2 - Desalination equipment

Info

Publication number: JP4139597B2
Application number: JP2001570560A
Authority: JP
Inventors: 祐三楢崎; 一郎神谷; 修行井上; 毅一入江; 徹徳丸; 知行内村
Original assignee: Ebara Corp
Current assignee: Ebara Corp
Priority date: 2000-03-31
Filing date: 2001-03-30
Publication date: 2008-08-27
Anticipated expiration: 2021-03-30
Also published as: AU2001244681A1; WO2001072638A1

Description

技術分野
本発明は、太陽エネルギーやその他の熱源を利用して海水，塩分を含んだ地下水（かん水）、産業廃水等から淡水（蒸留水）を得るための淡水化装置及び方法に関する。
背景技術
近年は、生活用水、工業用水，灌漑用水など、淡水の使用は増大し、水資源の保全、有効利用が益々重要な課題となってきている。
海水を淡水化する装置は、従来から知られており、中東などでは、大規模な淡水化プラントが設置されてきている。
しかし、淡水化装置は、基本的には、海水などの原水を加熱することにより水蒸気となし、これを凝縮して淡水を生成するのを基本的構成とするものであり、原水の加熱には、これまでは化石燃料や電力などのエネルギーを大量に消費して行うのが一般的であった。
これに対して、近年は、エネルギー消費ができるだけ少なく、しかも、効率良く淡水化のできる装置が望まれ、その開発が行われてきている。例えば、太陽熱を利用したものや、工業用タービンからの廃熱を利用するものなどが開発されてきており、その実用化も計られているが、それらのより一層の改善が望まれている。
本発明は、このような点に関しなされたものであり、より効率良く淡水化することのできる装置を提供することを目的とするものである。
発明の開示
すなわち、本発明は、熱源と、複数の蒸発器を備え、原水を前記熱源からの熱で加熱することにより同原水から水蒸気を発生させる蒸発装置と、蒸発装置内で加熱された原水から発生した水蒸気を当該蒸発装置の最後段の蒸発器から受け入れ凝縮させて蒸留水とするための凝縮器と、蒸発装置の蒸発器内の空間を大気圧以下に減圧する真空装置とを有し、蒸発器は、その最前段の蒸発器が外部からの原水を受け入れるようになされ、各蒸発器は所定量を超える原水を次段の蒸発器に流下するように接続されており、且つ、最前段の蒸発器の熱交換器には熱源からの熱が供給され、同最前段の熱交換器において原水から発生した水蒸気は次段の蒸発器の熱交換器に加熱源として供給され、該供給された水蒸気が当該次段の蒸発器において原水との熱交換によって凝縮されて発生した凝縮水と、同熱交換によって原水から発生した水蒸気とを、更に次段の蒸発器の熱交換器に加熱源として供給し、以下の蒸発器において同様の加熱源供給を行うようにされており、最後段の蒸発器で発生した水蒸気は前記凝縮器に供給されて凝縮されて蒸留水とされ、同最後段の蒸発器から排出される蒸留水とともに淡水として取り出されるようにしたことを特徴とする淡水化装置を提供する。この装置では、前段の蒸発器で発生した水蒸気と凝縮水とが次段の熱交換器での加熱源として用いられるので、当該淡水化装置内での熱を有効に利用することができる。
具体的には、真空装置は、各蒸発器の蒸発空間、該蒸発空間に連通する凝縮空間、及び、蒸留水貯蔵空間を減圧するようにし、また、最後段の蒸発器から排出される濃縮原水を、凝縮器の冷却水として使用するができる。また、蒸発器は、原水を受け入れるための貯留室を有し、最前段の蒸発器に供給される原水は、少なくとも一部の蒸発器の貯留室内を通る原水予熱管路を通された後に、最前段の蒸発器に供給されるようにすることもできる。更に、蒸発装置は、最前段の蒸発器の前段に配置された脱気室を有し、該脱気室は供給される原水を収容し、熱源からの熱によって加熱して当該原水中に含まれるガスを脱気し、該脱気した原水を該最前段の蒸発器に供給するようにすることができる。このようにすることにより、より効率よく淡水化作用を行うことができる。
また、１つの蒸発器において加熱源として使用され熱交換によって凝縮され発生した前記凝縮水を、次段の蒸発器へ加熱源として供給するための凝縮水通路を有し、該通路には絞りが設けられ、該絞りの前後で差圧が生じるようにすることができる。このようにすることにより、原水から脱気された不凝縮ガスが通路内に溜まらずに流下し、外部へ排出されやすくすることができ、これによっても原水と加熱源との間の熱交換をより適正に行うことを可能として効率的な淡水化作用を行うことができるようになる。
更に、本発明は、熱源と、原水を収容する脱気室，及び、該脱気室に続いて多段に配置した、原水を収容する複数の蒸発器を具備し、前記熱源から供給される熱により原水の加熱蒸発を行う蒸発装置であって、脱気室に原水が導入され、導入された原水が順次後段の蒸発器に送られるようになされており、且つ、各蒸発器において発生した原水からの水蒸気が後段の蒸発器の加熱源として送られるようになされた多重効用関係に接続されてなる蒸発装置と、該蒸発装置における最後段の蒸発器で発生された水蒸気を受け入れて凝縮し淡水を生成する凝縮器と、脱気室を大気圧以下に減圧し、該脱気室での原水加熱により発生した不凝縮ガスを排出する真空装置とを具備することを特徴とする淡水化装置を提供する。蒸発器に供給される原水が、脱気室で予め脱気されることにより、淡水化装置内に不凝縮ガスが滞留するのを低減し、それによって原水と加熱源との熱伝達をよくし、淡水化の効率を上げることができる。
この装置においては、真空装置によって、凝縮器の凝縮空間、該蒸発空間に連通する凝縮空間、及び、蒸発器の蒸発空間を減圧するようにし、この減圧と、上記脱気室の減圧とを切り換えて行うようにすることが好ましい。この切換は、減圧する空間内部の圧力に大きな差があり、同時に減圧することは効率的ではないからである。
また、脱気室と凝縮器の水蒸気入口側とは絞りを経由して真空装置に接続するようにするのが好ましい。これも前述と同様に、不凝縮ガスの滞留を防ぐためである。
具体的な例としては、蒸発器は上下に重ねられ、脱気室は、最上段の蒸発器の上に設定され、脱気室及び蒸発器は原水を貯留する貯留槽を有し、各貯留槽内に貯留された原水は、同貯留槽から溢水することにより、その下段にある蒸発器の貯留槽へ流下するようにされ、脱気室の貯留槽から溢水した原水は、Ｕ字管部分を有する管路を通して、最上段の蒸発器の貯留槽に流下されるようにされ、該Ｕ字管部分は、最上段の蒸発器における最高温度での飽和蒸気圧力と、前記真空装置によって前記脱気室にかけられる最高の減圧圧力との差圧に相当するヘッドを有するようにされる。また、熱源を、太陽エネルギーにより熱媒を加熱する太陽熱集熱器とし、該太陽熱集熱器からの熱媒蒸気を加熱源として、蒸発装置の脱気室と最上段の蒸発器の熱交換器に供給し、凝縮した凝縮熱媒を該太陽熱集熱器に戻すようにすることができる。
更に、本発明は、太陽熱を集熱して熱媒を加熱し熱媒の蒸気を発生させる集熱パネルを有する太陽熱集熱器と、熱媒と原水との間で熱交換を行うための熱交換器を有する蒸発装置と、該蒸発装置へ原水を供給する原水供給装置と、蒸発装置内で発生した水蒸気を受け入れ凝縮させて蒸留水とするための凝縮装置と、太陽熱集熱器で蒸気とされた熱媒を前記蒸発器の熱交換器へ供給する熱媒供給管路、及び、熱交換器での原水との熱交換により凝縮した熱媒を前記太陽熱集熱器へ帰還させる熱媒帰還管路を有し、当該熱媒の太陽熱集熱器での蒸発，及び、熱交換器での凝縮の繰り返しによるサーモサイフォン方式で該熱媒の循環を行う熱媒循環回路であって、熱媒帰還管路内に設けられ、同管路内の凝縮熱媒を太陽熱集熱器に向けて送給するためのポンプを有する熱媒循環回路とを有することを特徴とする淡水化装置を提供する。熱媒をポンプによって集熱パネルに供給することができるので、熱媒の集熱パネルに対するレベルを適正に維持することができ、集熱パネルでの、熱媒への集熱を適正に行うことができる。具体的には、この装置では、熱媒帰還管路内における前記ポンプの上流側に凝縮熱媒を収容するバッファタンクを設けることが好ましい。また、ポンプは少なくとも太陽熱集熱器が最大日射時に蒸発する熱媒量を該太陽熱集熱器に供給できる容量を有するものとされる。
更にまた、本発明では、熱源と、該熱源から供給される熱で原水を加熱し水蒸気を発生する蒸発装置と、該蒸発装置で発生した水蒸気を受け入れて冷却凝縮して淡水を生成する凝縮器と、蒸発装置内で水蒸気を発生して濃縮された原水を、前記凝縮器に導入して冷却水として使用する冷却装置とを備えることを特徴とする淡水化装置を提供する。冷却装置は、淡水化作用をより効率的に行うためのものである。この装置においては、冷却装置が、送風ファンを有し、該送風ファンによって濃縮原水を冷却して、凝縮器の冷却水として使用するようにすることができる。更に、蒸発装置が熱交換器を有し、熱源供給装置が太陽エネルギーにより熱媒を加熱する太陽熱集熱器とし、熱交換器は加熱された熱媒蒸気を受け入れて、原水との間で熱交換を行うようにすることができる。また、蒸発装置は多段に重ねられた複数の蒸発器を備え、各蒸発器は前記熱交換器を有し、これら蒸発器が各蒸発器において発生した原水からの水蒸気を下段の蒸発器に加熱源として送るようになされた多重効用関係に接続され、冷却装置は、最下段の蒸発器から排出された濃縮原水を前記凝縮器に導入して冷却水として使用するようにすることもできる。
発明の好適な実施例
以下、本発明の実施の形態例を図面に基づいて説明する。本実施の形態例では熱源として太陽エネルギーを用いた淡水化装置を例に説明する。図１は本発明に係る淡水化装置の構成例を示す図である。本淡水化装置は太陽熱集熱器１、蒸発装置２、冷却塔３、蒸留水タンク４、濃縮水タンク５及び真空手段６等から構成される。
太陽熱集熱器１は太陽エネルギーにより熱媒を加熱する複数の太陽熱集熱パネル１−１〜１−６からなる。該太陽熱集熱器１で加熱された熱媒は配管７を通って蒸発装置２に送られ、蒸発装置２からの熱媒は配管８を通してバッファタンク９に収容され、更に該バッファタンク９から熱媒循環ポンプ２６及び配管１０を通して太陽熱集熱器１に戻り循環するようになっている。
蒸発装置２は最上部に脱気室２−１が配置され、その下に複数台の蒸発器（ここでは第１蒸発器２−２〜第８蒸発器２−９の８台）が配置されて構成されている。原水（ここでは海水）Ｗは、（図１の右下から延び）蒸発装置２内を下から上に順次配管された原水予熱管路１２を通された後、同蒸発装置２の最上位にある脱気室２−１に供給される。脱気室２−１に供給された原水は、所定量だけ貯留されるとオーバーフローして、オーバーフロー管１３を通して、第１蒸発器２−２に流下し、同様にして、第２〜第８蒸発器２−９の各蒸発器に所定量だけ貯留しながら流下するとともに、加熱蒸発されて次第に濃縮されて、最後にオーバーフロー管１４を通って濃縮水タンク５に収容されるようになっている。
太陽熱集熱器１からの加熱された熱媒の一部は脱気室２−１内に配置された熱交換器２−１ａを通され、他は第１蒸発器２−２内に配置された熱交換器２−２ａを通されて（図２参照）、該脱気室２−１及び第１蒸発器２−２内に貯留されている原水Ｗとの間で熱交換が行われる。第１蒸発器２−２の原水の加熱で蒸発した水蒸気は蒸気配管１５を通って第２蒸発器２−３の熱交換器２−３ａに熱源として送られ原水との間で熱交換が行われる。また、第３蒸発器２−４〜第７蒸発器２−８の原水の加熱で蒸発した水蒸気も次段の蒸発器の熱交換器に熱源として送られ原水との間で熱交換が行われ、凝縮されて蒸留水となって最後に蒸留水タンク４に収容される。
濃縮水タンク５の濃縮原水は濃縮原水排出ポンプ１６により配管２７を通って冷却塔３の凝縮器３−１の下部タンク３−１ａに送られ、更に濃縮原水循環ポンプ１７で散水ノズル３−１ｃに供給され、凝縮（伝熱）パイプ３−１ｂ上に冷却水として散水されるようになっている。最終段の第８蒸発器２−９での原水の加熱で蒸発した水蒸気は配管１８を通って凝縮器３−１の凝縮パイプ３−１ｂに送られ、上記散水された濃縮原水との間で熱交換が行われ、凝縮して蒸留水となり配管１９を通って蒸留水タンク４に送られる。下部タンク３−１ａをオーバーフローした濃縮水は濃縮水排出管路２０を通って排水される。
真空手段６は気液分離器６−１及び該気液分離器６−１に接続された真空ポンプ６−２を具備する。気液分離器６−１は配管２１、２２、２３を介して太陽熱集熱器１からの熱媒が通る配管７、蒸発装置２の脱気室２−１、凝縮器３−１のヘッダー３−１ｄに接続される。これにより後に詳述するように、蒸発装置２の蒸発空間及びこれに連通する凝縮空間及び蒸留水貯蔵空間を減圧状態にすることができる。
また、蒸留水タンク４の蒸留水Ｗｂは蒸留水ポンプ２５により排出するようになっている。なお、図１において、Ｖ１〜Ｖ８はパルプである。
図２は上記淡水化装置の太陽熱集熱器１と蒸発装置２の一部の詳細を示す図である。図示するように、太陽熱集熱器１の複数の太陽熱集熱パネル１−１〜１−６で加熱されて蒸気となった熱媒蒸気Ｑ１は脱気室２−１の熱交換器２−１ａ及び第１蒸発器２−２の熱交換器２−２ａを通って脱気室２−１及び第１蒸発器２−２に貯留されている原水Ｗとの間で熱交換が行なわれ、凝縮し凝縮熱媒Ｑ２となってバッファタンク９に収容される。凝縮熱媒Ｑ２は熱媒循環ポンプ２６を介して太陽熱集熱器１の各太陽熱集熱パネル１−１〜１−６に送られる。
図３は上記淡水化装置の蒸発装置２の一部、濃縮水タンク５及び蒸留水タンク４の詳細を示す図である。原水予熱管路１２は第８蒸発器２−９〜第２蒸発器２−３に貯留される原水Ｗ内を通るように配管され、該原水予熱管路１２内を通される原水Ｗが各蒸発器内の原水（濃縮原水）Ｗとの間での熱交換により予熱されるようになっている。原水予熱管路１２を通って予熱された原水Ｗは脱気室２−１に供給され、該脱気室２−１をオーバーフローした原水Ｗは、出口部がＵ字状に形成されたオーバーフロー管１３を通して第１蒸発器２−２に供給される。該オーバーフロー管１３のＵ字状部１３ａは、最上段の蒸発器である第１蒸発器２−２の最高温度に相当する飽和蒸気圧力と真空手段６の最高到達真空度との差圧に相当するヘッドを有する。また、該第１蒸発器２−２をオーバーフローした原水Ｗは、オーバーフロー管１３を通して第２蒸発器２−３に供給され、同様にして、最終段の第８蒸発器２−９まで流下し、各蒸発器には所定量の原水が貯留される。
第１蒸発器２−２で蒸発した水蒸気Ｗａは第２蒸発器２−３の熱交換器２−３ａを通って原水Ｗとの間で熱交換が行われ凝縮し、蒸留水Ｗｂとなって該第２蒸発器２−３で発生した水蒸気Ｗａとともに第３蒸発器２−４の熱交換器２−４ａに送られ原水との間で熱交換が行われる。そして凝縮し蒸留水Ｗｂとなって第３蒸発器２−４で発生した水蒸気Ｗａとともに第４蒸発器２−５の熱交換器２−５ａに送られる。このように、各蒸発器で順に蒸発・凝縮が繰返され、最終段の第８蒸発器２−９の熱交換器２−９ａで凝縮した蒸留水Ｗｂは蒸留水タンク４に供給される。
図４は上記淡水化装置の真空手段６、冷却塔３及び蒸発装置２の一部の詳細を示す図である。図示するように、脱気室２−１、熱媒が通る配管７及び冷却塔３の凝縮器３−１が配管２１、２２、２３を通して真空ポンプ６−２に接続されている。これにより、脱気室２−１の内部空間、配管７及びこれに連通する第１蒸発器２−２の内部空間、冷却塔３のヘッダー３−１ｄや凝縮パイプ３−１ｂ内の凝縮空間を減圧できるようになっている。なお、第２蒸発器２−３以降の各蒸発器の蒸発空間及び凝縮空間は蒸気配管１５で連通されており、同様に減圧できるようになっている。また、排気は真空ポンプ６−２の吐出口に接続された排気パイプ６−３を通して行なわれる。
図５は上記淡水化装置の蒸留水タンク４、濃縮水タンク５及び冷却塔３の詳細を示す図である。蒸発装置２の第８蒸発器２−９で蒸発した水蒸気Ｗａは配管１８を通って凝縮器３−１に送られ、凝縮パイプ３−１ｂを通る間に散水ノズル３−１ｃから散布される濃縮原水Ｗ及びファン３−２から送られる空気との間で熱交換によって冷却が行なわれ、凝縮水Ｗｂとなって蒸留水タンク４に送られる。このとき散水ノズル３−１ｃから散布される濃縮原水Ｗは、ファン３−２から送られた空気で冷却されるから、水蒸気Ｗａは効率良く凝縮される。
上記構成の淡水化装置には、大気圧以上で常に原水を供給できる原水タンク（図示せず）を設置する。淡水化装置の設置初期は、蒸発装置２等の運転時に真空状態が要求される系（蒸発装置２の各蒸発器の蒸発空間及び蒸発空間に連通する凝縮空間、冷却塔３の凝縮器３−１の凝縮空間、蒸留水タンク４及び濃縮水タンク５の蒸留水及び濃縮水貯蔵空間）の減圧を行う。そしてバルプＶ８を開くことにより、真空圧を利用して原水を規定量投入する。当該淡水化装置は、運転開始後、常時減圧状態であるため、蒸発量に応じて第１蒸発器２−２の原水Ｗの液面を維持するように自動的にバルプＶ８を開閉制御することで、原水Ｗを当該淡水化装置内に供給することができる。なお、原水Ｗの供給は原水供給ポンプ１１を用いて供給してもよい。
太陽熱集熱器１は太陽エネルギーを吸収し、内部の熱媒を加熱する。内部が減圧されている太陽熱集熱器１内で加熱された熱媒は蒸発し熱媒蒸気Ｑ１となり、脱気室２−１の熱交換器２−１ａ及び第１蒸発器２−２の熱交換器２−２ａに導入され、これらに貯留されている原水Ｗとの間で熱交換が行われ、原水Ｗは加熱され、熱媒蒸気Ｑ１は凝縮して凝縮熱媒Ｑ２となる。このように熱媒は蒸発・凝縮を繰り返すことにより自然循環、即ちサーモサイフォンにより循環されるが、ここでは更に、熱循環ポンプ８により凝縮熱媒Ｑ２を太陽熱集熱器の集熱パネル１−１〜１−ｎに強制的に送給できるようにしてあり、太陽熱集熱器内での熱媒のレベルを一定に保つことができるようにしている。
第１蒸発器２−２の原水Ｗは、熱媒蒸気Ｑ１により加熱されると蒸発して水蒸気Ｗａを発生する。この水蒸気Ｗａは第２蒸発器２−３の熱交換器２−３ａに送給され、該第２蒸発器２−３に貯留されている原水Ｗとの間で熱交換が行われ、原水Ｗを加熱すると同時に熱を奪われ凝縮して蒸留水Ｗｂとなる。該原水Ｗの加熱で発生した水蒸気Ｗａは第３蒸発器２−４の熱交換器２−４ａに移送され、該第３蒸発器２−４に貯留されている原水Ｗとの間で熱交換が行われ、原水Ｗを加熱すると同時に熱を奪われ凝縮して蒸留水Ｗｂとなる。このように同じプロセスを繰り返す。
第８蒸発器２−９の前段の第７蒸発器２−８で蒸発した水蒸気Ｗａは第８蒸発器２−９の熱交換器２−９ａに移送され、原水Ｗとの間で熱交換が行われ、原水Ｗを加熱すると同時に熱を奪われ凝縮して蒸留水となり蒸留水タンク４に移送される。また、最終段の第８蒸発器２−９で蒸発した水蒸気Ｗａは、冷却塔３内の凝縮器３−１へ移送され、ここで散水ノズル３−１ｃから散布される濃縮原水Ｗとファン３−２から送られる空気により、熱を奪われ凝縮し蒸留水となる。そして蒸留水タンク４へと移送される。
蒸発装置２に供給される原水Ｗは第８蒸発器２−９〜第２蒸発器２−３内の原水Ｗ内を通る原水予熱管路１２内を通る。第８蒸発器２−９〜第２蒸発器２−３内に貯留されている原水Ｗは熱を保有しており、原水予熱管路１２を通る原水Ｗとの間で熱交換が行われ、該原水予熱管路１２を通る原水Ｗは予熱される。これにより第８蒸発器２−９〜第２蒸発器２−３内の濃縮原水Ｗが保有する熱を有効に使用する。
更に、原水Ｗ中に含まれる不凝縮ガスを第１蒸発器２−２〜第８蒸発器２−９の各蒸発器に供給する前に脱気室２−１で脱気されることになる。不凝縮ガスを脱気しない場合は、蒸発器において原水の加熱蒸発を行った際に水蒸気内に、この不凝縮ガスも入り込み、各蒸発器内の熱交換器における水蒸気と原水Ｗａとの間の伝熱を阻害することになるので、この点、上記不凝縮ガスの脱気は、蒸留性能を向上させることになる。
第１蒸発器２−２〜第７蒸発器２−８の各蒸発器で発生した水蒸気Ｗａは、後段の蒸発器の原水Ｗを加熱して凝縮され蒸留水となり、当該後段の蒸発器での原水Ｗの加熱により発生した水蒸気Ｗａと一緒になって、更に後段の蒸発器の熱交換器に導入される。つまり第１蒸発器２−２〜第７蒸発器２−８の各蒸発器は、蒸気配管１５、及び、水蒸気が凝縮されて生成された蒸留水Ｗｂが通る絞り付き蒸留水流路２８により、互いに連通されている。これにより、水蒸気Ｗａの凝縮潜熱だけでなく蒸留水Ｗｂの顕熱も有効に利用することができる。また、蒸留水流路２８を絞り（オリフィス）付きとすることにより、当該蒸留水流路２８が連通する前段の蒸発器の水蒸気凝縮空間と後段の蒸発器の水蒸気凝縮空間との間に圧力差を生じ、このため、不凝縮ガスが同前段の凝縮器内にとどまらずに凝縮水と共に後段側の蒸発器へ流下されるようになる。不凝縮ガスの蒸発器内での滞留は、各蒸発器内の熱交換器における水蒸気と原水Ｗａとの間の伝熱を阻害するが、これを防止することができる。
第１蒸発器２−２〜第８蒸発器２−９の各蒸発器は、供給される原水Ｗが常時規定量を維持するように各蒸発器内にオーバーフロー管１３が配置されており、該オーバーフロー管１３を通しオーバーフローした濃縮原水Ｗは後段の蒸発器に原水Ｗとして導入されている。つまり、各蒸発器は前段の蒸発器から濃縮原水を順次供給されるようになっている。これにより、前段の蒸発器の温度レベルの高い原水が、次段の蒸発器の原水の熱源となり、より効率がよくなる。
このように各段の蒸発器が互いに連通しているので、原水Ｗを連続的に供給することができ、また蒸留水Ｗｂ及び濃縮原水Ｗを連続的に排水することができる。よって第１蒸発器２−２〜第８蒸発器２−９の各段の蒸発器の原水Ｗの保有量が少なくて済むので、淡水化装置がコンパクトになる上、保有原水Ｗの熱量も少なくて済む。これにより、少ない熱供給量で多くの蒸留水Ｗｂが得られ、効率のよい運転が可能となる。そして原水Ｗの保有量が少ないことから、日射変動による応答性が速く効率のよい運転が可能となる。
第１蒸発器２−２〜第８蒸発器２−９の各段の蒸発器で蒸発・凝縮した蒸留水は蒸留水タンク４で一緒になる。そして、蒸留水タンク４内の蒸留水量が規定量に達したら、又は連続的に、蒸留水ポンプ２５で大気圧である系外に排出・回収される。
第１蒸発器２−２〜第８蒸発器２−９の各段の蒸発器で蒸発せず通過した濃縮原水Ｗは濃縮水タンク５にたどり着く。そして濃縮水タンク５内の濃縮原水量が規定量に達したら又は連続的に濃縮原水排出ポンプ１６で冷却塔３の凝縮器３−１の下部タンク３−１ａに移送され、該下部タンク３−１ａの濃縮原水は冷却用水として濃縮原水循環ポンプ１７により散水ノズル３−１ｃに供給され、凝縮パイプ３−１ｂ上に散水される。
第１蒸発器２−２への原水Ｗの供給量は、各蒸発器でのスケーリングを防ぎ、メンテナンス性を向上させ、且つ耐久性を向上させるため、各蒸発器２−２〜２−９の蒸発器内の熱交換器２−２ａ〜２−９ａが原水から常時ドライアップしないようにしており、また各蒸発器を通過して濃縮水タンク５から移送・排出される濃縮原水Ｗの濃縮倍率をスケールの析出倍率（例えば海水の場合１．５）以下になるように設定している。
冷却塔３を設置して最終段の濃縮原水Ｗの温度を外気温付近に一定に保つことで、例えば冷却タンクを有するバッチ方式の淡水化装置で問題となる冷却タンクの冷却水温度上昇（淡水化装置全体の保有熱量の増大）による午後の蒸留性能の低下を防ぐことができ、高い蒸留水の収量を確保できる。また、最終段の第８蒸発器２−９で蒸発した水蒸気Ｗａの冷却を連続的に行えるため連続的な蒸発・凝縮が可能となり、太陽熱集熱器１以外に熱源を確保できれば２４時間連続して運転をすることもできる。
このように原水Ｗの保有量及び保有熱量が少ないこと、冷却塔３を設置して最終段の凝縮水Ｗの温度をほぼ外気温度（例えば外気温３０°Ｃ）に一定に保てること、すなわち、凝縮水の温度上昇を防ぐこと、及び、連続運転を行うことで、例えば通常の太陽熱集熱パネル１−１〜１−６で集められる集熱温度（例えば熱媒蒸気入口温度６５°Ｃ）と原水入口温度（例えば原水入口温度３２°Ｃ）から、本実施例では蒸発装置２を第１蒸発器２−２〜第８蒸発器２−９の八重効用とした。これにより、エネルギー密度の薄い太陽エネルギーを八回繰返し有効に使用することができる。
バッチ式淡水化装置では、原水を入れ替える毎に、当該装置の大気圧からの真空引きが必要となり、非常に大きい電力消費を必要とするが、上述した本発明に係る淡水化装置では、最初の段階で大気圧からの真空引きを行い装置全体を減圧状態にした後は、原水を連続的に供給して運転を行い、それに伴なって生じる不凝縮ガスの排出が必要となるだけで、大気圧からの真空引きは必要がないので、大幅なエネルギー削減を行うことができる。
太陽が沈み日射がなくなると、蒸発が終了し原水の供給が停止する。つまり、淡水化運転が停止する。そして翌日、太陽が昇り、蒸発装置２内での蒸発が始まると蒸発した分だけ原水Ｗが新たに供給され淡水化サイクルが回り始める。このことから、熱が供給されているときのみポンプ等を駆動すれぱ淡水化運転は可能である。つまり、太陽の日射があって太陽熱集熱器１から蒸発装置２に熱源が供給されているときは同時に発電ができ、必要な電力が供給できる太陽光発電システムを備えることで自立型の淡水化装置になる。
また、連続運転が可能であれば太陽熱集熱器１から蒸発装置２に熱源が供給されているときのみポンプ等を駆動すればよい。つまり、太陽光発電設備を装備していれば、太陽の日射があって熱源が供給されているときは同時に発電ができ必要な電力を供給できる。
また、ポンプ等の電動機器は間欠・時差運転とすることで太陽光発電システムのピーク時の必要容量を抑えることができ、更にＡＣ負荷機器運転に必要な太陽光発電システムの直流の電気を交流に変換するインバータの容量を小さくすることができるため、コンパクトな太陽光発電システムを構築できる。そして、システムと運転フローの最適化ができれば蓄電設備は不要となり、より一層のコンパクトで安全でメンテナンスフリーの電力供給システムを構築することができる。
真空ポンプは、エネルギー密度の薄い太陽エネルギーを繰返し使用するために、ある程度の高真空（例えば外気温３０°Ｃのときの飽和蒸気圧３１．８ｍｍＨｇ）を必要とするため、今までの淡水化装置では真空手段として油回転型の真空ポンプを使用したが、運転時には水蒸気を吸引してしまうため、油に水が混入してしまい油の劣化による真空到達度の低下及びポンプの故障に悩まされてきた。ここでは、油水分離タンクを設置し又油水分離に必要な時間装置を停止する（例えば一日一回夜間等の８時間）ことで油から水を分離できるようになった。これにより、毎日の運転が可能となった。更に、油を使わないスクロール型の真空ポンプ等を使うことで油のメンテナンスが不要となり２４時間連続運転も可能となる。
蒸発装置２を構成する第１蒸発器２−２〜第８蒸発器２−９の各蒸発器は伝熱管を水平方向に長く設置した横型蒸発器とすることで十分に広い蒸発面積を確保でき、蒸気速度を抑えられるので、水蒸気Ｗａに同伴するミスト（すなわち、塩分を含んだ原水の微少液滴）の量を低下させることができる。また、蒸発器内の水蒸気の蒸発面から同蒸発器の蒸気出口までの高さを十分にとること及び蒸発器と蒸気出口までの流路に水蒸気と一緒に同伴するミストを捕集するためのバッフル板を備えることで、高品質の蒸留水を得ることができた（本実施例では５μＳ／ｃｍ）。
また、第１蒸発器２−２〜第８蒸発器２−９のように、蒸発器を多重効用とする場合は、縦型一体構造とすることでコンパクト化し、また水蒸気Ｗａ、蒸留水Ｗｂ及び濃縮原水Ｗを自然流下とすることで余計な動力を不要にする。また、現地搬入・工事は本体設置と架台及びパネル類の組立てだけであり、作業が容易となる。
図６は本発明に係る淡水化装置の他の構成例を示す図である。本淡水化装置が図１に示す淡水化装置と異なる点は、脱気室２−１と凝縮器３−１の水蒸気入口側、即ち第８蒸発器２−９から水蒸気を凝縮器３−１に導入する配管１８とをオリフィス等の絞り３０を経由して連通させている点である。これは、絞り３０の前後に圧力差を設けることにより、脱気室２−１で脱気された不凝縮ガスが脱気室内に留まらず、配管２９内を流下し、凝縮器３−１、配管２３、バルブＶ３、及び、真空手段６を介して外部へ流出しやすくするためである。
以上で述べた実施例では、熱源として太陽熱集熱器１を用いる例を示したが、熱源はこれに限定するものではなく、外部熱源を蒸発装置２に直接又は間接的に供給できるものであればよい。
上述した実施例に係る淡水化装置では、次のような効果を得ることが可能となる。
（１）真空手段で蒸発装置の各蒸発器の蒸発空間及び該蒸発空間に連通する凝縮空間及び蒸留水貯蔵空間を減圧し、前段の蒸発器で発生した水蒸気を当該蒸発器の熱交換器に熱源として導入し、発生した水蒸気と凝縮した蒸留水を熱源として次段の蒸発器の熱交換器に供給するようにし、複数個の蒸発器を多重効用としたので、太陽エネルギー等の低いエネルギー密度の熱源を利用して効率よく原水から淡水が得られる。
（２）また、各段の蒸発器で発生する水蒸気、蒸留水及び所定量を超える原水を次段の蒸発器に供給するように、各蒸発器を互いに連通させているので、連続的に原水が供給でき、蒸留水及び濃縮原水を連続的に排出する連続運転が可能となる。また、各段の蒸発器が保有する原水量が少なくて済み装置がコンパクトになる上、保有熱量も少なくて済むから、少ない供給熱量で多くの蒸留水が得られる効率の良い淡水化運転が可能となる。また、連続運転が可能となることから、淡水化装置で最も電力を必要とする蒸発器の蒸発空間、それに連通する凝縮空間、蒸留水貯蔵空間等の大気圧からの真空引きが、運転開始後は不要となる。
（３）また、最終段の蒸発器で発生した水蒸気を冷却塔の凝縮器に供給し、該凝縮器では濃縮水タンクの濃縮原水を冷却水として使用するので、最終段の濃縮水温度を外気温度付近に保つことができ、例えば冷却タンクを有するバッチ方式の淡水化装置で問題となる冷却タンクの冷却水温度上昇（装置全体の保有熱量の増大）による午後の蒸留性能の低下を防ぐことができる。また、最終段の蒸発器で蒸発した水蒸気の凝縮を凝縮器で連続的に行えるため連続的な蒸発・凝縮が可能になり、熱源が確保できれば、２４時間連続して淡水化運転ができる。
（４）また、前段の蒸発器で発生した水蒸気と凝縮水を当該蒸発器の熱交換器に熱源として導入し、発生した水蒸気と凝縮した蒸留水を熱源として次段の蒸発器の熱交換器に供給するようにするので、水蒸気Ｗａの凝縮潜熱だけでなく蒸留水の顕熱も有効に利用することができる。
（５）また、各蒸発器は所定量を超える原水を次段の蒸発器に供給するようにしたので、前段の蒸発器の温度レベルの高い原水が次段の蒸発器の原水の熱源となり、より効率がよくなる。
（６）凝縮器と協働する冷却塔を設けたので、凝縮器に冷却水として供給される濃縮原水を冷却塔が具備するファンから送られる空気により強制的に冷却することが可能となり、凝縮器の凝縮効率を高く、安定的に維持することができ、高効率の淡水化運転が可能となる。
（７）冷却塔を用いることにより、凝縮温度を低く保つことができることによって太陽熱集熱器での集熱温度が下がるから、集熱効率上昇及び集熱量増が可能となり、淡水収量の増大が期待できる。
（８）蒸発装置の蒸発器に供給される原水を原水予熱管路を通して少なくとも一部の蒸発器の原水（既に蒸発装置内に供給され加熱を受けている原水）の保有する熱で予熱するので、蒸発装置内の熱を有効に利用することができる。
（９）蒸発装置は、最前段の蒸発器の前段に脱気室を配置するので、伝熱を阻害する不凝縮ガスを取り除くことができ、蒸留性能を向上させることができ、また、淡水化操作をバッチ式でなく連続的に行うことができる。
（１０）脱気室と凝縮器の水蒸気入口側とを絞りを経由して連通させることにより、該脱気室で発生した不凝縮ガスを該凝縮器の凝縮空間から真空手段を介して脱気排出するのが容易となる。また、絞りを、蒸発器と蒸発器との間の凝縮水通路にも設けることにより、不凝縮ガスの排出を容易にし、該ガスが蒸発器内に滞留することによる熱交換の阻害を防止することができる。
（１１）熱媒循環回路における凝縮熱媒流路に、凝縮熱媒を循環させる熱媒循環手段を設けることにより、集熱器の集熱パネルを最も集熱量の多い角度に設置しても、また日の出時の初期蒸発時でも、また太陽熱集熱器全体の液溜り等の問題から熱媒液面が変動しても、集熱パネルの伝熱面を熱媒体によって満たすことができ、一日の全日射量を有効に使え、且つ日射の間欠性（日射変動）に対して熱媒の蒸発までの追従性をよくすることができるという優れた効果が得られる。
発明の利用可能性
本発明に係る淡水化装置は、化石燃料や電力を熱源とする従来装置のように、その熱源設備が得られるような限られた場所でのみ使用できるのとは異なり、都市などから離れたどのような所にも設置可能であり、太陽エネルギー等の低密度のエネルギーを効率的に利用し、淡水化を行うことが可能である。
【図面の簡単な説明】
図１は、本発明の一実施例に係る淡水化装置の構成例を示す図である。
図２は、同淡水化装置の太陽熱集熱器と蒸発装置の一部の詳細構成例を示す図である。
図３は、同淡水化装置の蒸発装置の一部と濃縮水タンク及び蒸留水タンクの詳細構成例を示す図である。
図４は、同淡水化装置の真空手段と冷却塔と蒸発装置の一部の詳細構成例を示す図である。
図５は、同淡水化装置の蒸留水タンクと濃縮水タンクと冷却塔の詳細構成例を示す図でる。
図６は、他の実施例に係る淡水化装置の構成例を示す図である。Technical field
The present invention relates to a desalination apparatus and method for obtaining fresh water (distilled water) from seawater, salty groundwater (brine), industrial wastewater, and the like using solar energy and other heat sources.
Background art
In recent years, the use of fresh water such as domestic water, industrial water, and irrigation water has increased, and the conservation and effective use of water resources has become an increasingly important issue.
An apparatus for desalinating seawater has been conventionally known, and large-scale desalination plants have been installed in the Middle East and the like.
However, the desalination device basically has the basic structure of generating raw water by heating raw water such as seawater and condensing it to produce raw water. Until now, it was common to consume large amounts of energy such as fossil fuels and electricity.
On the other hand, in recent years, a device that consumes as little energy as possible and that can efficiently desalinate is desired and has been developed. For example, those using solar heat and those using waste heat from industrial turbines have been developed and put to practical use, but further improvements are desired.
This invention is made | formed regarding such a point, and it aims at providing the apparatus which can desalinate more efficiently.
Disclosure of the invention
That is, the present invention includes a heat source, a plurality of evaporators, an evaporator that generates steam from the raw water by heating the raw water with heat from the heat source, and generated from the raw water heated in the evaporator. A condenser for accepting and condensing water vapor from the last stage evaporator of the evaporator to form distilled water, and a vacuum apparatus for reducing the space in the evaporator of the evaporator to an atmospheric pressure or lower, the evaporator The first stage evaporator is adapted to receive the raw water from the outside, each evaporator is connected so as to flow a predetermined amount of raw water down to the next stage evaporator, and the first stage evaporator Heat from the heat source is supplied to the heat exchanger of the evaporator, and the steam generated from the raw water in the front-stage heat exchanger is supplied as a heating source to the heat exchanger of the next-stage evaporator, and the supplied steam In the next stage evaporator, Condensed water generated by condensation by heat exchange and water vapor generated from raw water by the heat exchange are further supplied as a heat source to the heat exchanger of the next-stage evaporator. The water vapor generated in the last stage evaporator is supplied to the condenser and condensed to be distilled water, which is taken out as fresh water together with the distilled water discharged from the last stage evaporator. The desalination apparatus characterized by being made to provide is provided. In this apparatus, water vapor and condensed water generated in the previous stage evaporator are used as a heating source in the next stage heat exchanger, so that heat in the desalination apparatus can be used effectively.
Specifically, the vacuum device depressurizes the evaporation space of each evaporator, the condensation space communicating with the evaporation space, and the distilled water storage space, and the concentrated raw water discharged from the last-stage evaporator. Can be used as cooling water for the condenser. Further, the evaporator has a storage chamber for receiving raw water, and the raw water supplied to the foremost evaporator is passed through the raw water preheating conduit passing through the storage chamber of at least some of the evaporators. It can also be made to supply to the evaporator of the foremost stage. Further, the evaporation apparatus has a deaeration chamber disposed in front of the front-stage evaporator, and the deaeration chamber contains raw water to be supplied, is heated by heat from a heat source, and is included in the raw water. The degassed raw water can be supplied to the foremost evaporator. By doing in this way, desalination can be performed more efficiently.
In addition, a condensate water passage is provided for supplying the condensed water that is used as a heat source in one evaporator and condensed and generated by heat exchange to the next-stage evaporator as a heat source. It is possible to provide a differential pressure before and after the restriction. By doing so, the non-condensable gas degassed from the raw water can flow down without being accumulated in the passage and can be easily discharged to the outside. This also facilitates heat exchange between the raw water and the heating source. It becomes possible to perform more appropriately, and an efficient desalination effect can be performed.
Furthermore, the present invention comprises a heat source, a deaeration chamber for accommodating the raw water, and a plurality of evaporators for accommodating the raw water, arranged in multiple stages following the deaeration chamber, and the heat supplied from the heat source Is an evaporation device that heats and evaporates the raw water, the raw water is introduced into the deaeration chamber, and the introduced raw water is sequentially sent to the subsequent evaporator, and the raw water generated in each evaporator The vaporizer connected to the multi-effect relationship is designed to send the water vapor from the latter stage as a heating source for the subsequent stage evaporator, and receives and condenses the water vapor generated by the last stage evaporator in the evaporator to produce fresh water A desalination apparatus comprising: a condenser for generating a deaeration chamber; and a vacuum apparatus for depressurizing the deaeration chamber below atmospheric pressure and discharging non-condensable gas generated by heating the raw water in the deaeration chamber. provide. The raw water supplied to the evaporator is deaerated in advance in the deaeration chamber to reduce the retention of non-condensable gas in the desalination unit, thereby improving the heat transfer between the raw water and the heating source. , Can improve the efficiency of desalination.
In this apparatus, the condensing space of the condenser, the condensing space communicating with the evaporating space, and the evaporating space of the evaporator are depressurized by a vacuum device, and this depressurization and the deaeration chamber are depressurized. It is preferable to do so. This switching is because there is a large difference in the pressure inside the space to be depressurized, and simultaneously depressurizing is not efficient.
The deaeration chamber and the water vapor inlet side of the condenser are preferably connected to a vacuum apparatus via a throttle. This is also to prevent the non-condensable gas from staying in the same manner as described above.
As a specific example, the evaporators are stacked one above the other, the deaeration chamber is set on the uppermost evaporator, the deaeration chamber and the evaporator have a storage tank for storing raw water, and each storage The raw water stored in the tank overflows from the storage tank and flows down to the evaporator storage tank at the lower stage, and the raw water overflowed from the storage tank of the deaeration chamber is the U-shaped pipe part. The U-tube portion is allowed to flow down to the uppermost evaporator in the uppermost evaporator through the pipe line having A head corresponding to a pressure difference from the highest pressure applied to the air chamber is provided. Further, the heat source is a solar heat collector that heats the heat medium with solar energy, and the heat medium vapor from the solar heat collector is used as a heat source, and the heat exchanger of the deaeration chamber of the evaporator and the uppermost evaporator And the condensed condensed heat medium can be returned to the solar heat collector.
Furthermore, the present invention provides a solar heat collector having a heat collection panel that collects solar heat to heat the heat medium and generate steam of the heat medium, and heat exchange for heat exchange between the heat medium and raw water An evaporator having an evaporator, a raw water supply apparatus for supplying raw water to the evaporator, a condenser for receiving and condensing water vapor generated in the evaporator to form distilled water, and a solar heat collector Heat medium supply pipe for supplying the heated heat medium to the heat exchanger of the evaporator, and a heat medium return pipe for returning the heat medium condensed by heat exchange with the raw water in the heat exchanger to the solar heat collector A heating medium circulation circuit having a path and circulating the heating medium in a thermosiphon system by repeatedly evaporating the heating medium in a solar heat collector and condensing in a heat exchanger. It is installed in the pipe and the condensing heat medium in the pipe is sent to the solar heat collector. Providing desalination apparatus characterized by having a heat medium circulation circuit having a pump. Since the heat medium can be supplied to the heat collection panel by a pump, the level of the heat medium relative to the heat collection panel can be maintained appropriately, and the heat collection to the heat medium at the heat collection panel should be performed appropriately. Can do. Specifically, in this apparatus, it is preferable to provide a buffer tank for storing the condensed heat medium in the heat medium return pipe upstream of the pump. The pump has at least a capacity capable of supplying the solar heat collector with a heat medium amount that evaporates at the time of maximum solar radiation.
Furthermore, in the present invention, a heat source, an evaporator that heats raw water with heat supplied from the heat source to generate water vapor, and a condenser that receives the water vapor generated by the evaporator and cools and condenses to produce fresh water. And a cooling device for introducing raw water concentrated by generating water vapor in the evaporator into the condenser and using it as cooling water. The cooling device is for performing the desalination operation more efficiently. In this apparatus, the cooling device has a blower fan, and the concentrated raw water can be cooled by the blower fan and used as cooling water for the condenser. Further, the evaporator has a heat exchanger, and the heat source supply device is a solar heat collector that heats the heat medium by solar energy, and the heat exchanger receives the heated heat medium vapor and heats it with the raw water. Exchanges can be made. The evaporator includes a plurality of evaporators stacked in multiple stages, and each evaporator has the heat exchanger, and these evaporators heat the water vapor generated in each evaporator from raw water to the lower evaporators. Connected to the multi-effect relationship that is designed to be sent as a source, the cooling device can introduce the concentrated raw water discharged from the lowermost evaporator into the condenser and use it as cooling water.
Preferred embodiments of the invention
Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, a desalination apparatus using solar energy as a heat source will be described as an example. FIG. 1 is a diagram showing a configuration example of a desalination apparatus according to the present invention. The desalination apparatus includes a solar heat collector 1, an evaporator 2, a cooling tower 3, a distilled water tank 4, a concentrated water tank 5, a vacuum means 6, and the like.
The solar heat collector 1 includes a plurality of solar heat collection panels 1-1 to 1-6 that heat a heat medium by solar energy. The heat medium heated by the solar heat collector 1 is sent to the evaporator 2 through the pipe 7, and the heat medium from the evaporator 2 is accommodated in the buffer tank 9 through the pipe 8, and is further heated from the buffer tank 9. The medium is circulated back to the solar heat collector 1 through the medium circulation pump 26 and the pipe 10.
In the evaporator 2, a deaeration chamber 2-1 is disposed at the top, and a plurality of evaporators (here, eight of the first evaporator 2-2 to the eighth evaporator 2-9) are disposed below it. Configured. The raw water (here, seawater) W (extending from the lower right in FIG. 1) passes through the raw water preheating pipe 12 that is sequentially piped from the bottom to the top in the evaporator 2, and then reaches the top of the evaporator 2. It is supplied to a certain deaeration chamber 2-1. The raw water supplied to the degassing chamber 2-1 overflows when a predetermined amount is stored, flows down to the first evaporator 2-2 through the overflow pipe 13, and similarly, the second to eighth evaporations. It flows down while being stored in a predetermined amount in each evaporator of the vessel 2-9, is heated and evaporated, is gradually concentrated, and finally is stored in the concentrated water tank 5 through the overflow pipe 14.
Part of the heated heat medium from the solar heat collector 1 is passed through the heat exchanger 2-1a disposed in the deaeration chamber 2-1, and the other is disposed in the first evaporator 2-2. Then, heat exchange is performed between the deaeration chamber 2-1 and the raw water W stored in the first evaporator 2-2 through the heat exchanger 2-2a (see FIG. 2). The water vapor evaporated by heating the raw water of the first evaporator 2-2 passes through the steam pipe 15 and is sent as a heat source to the heat exchanger 2-3a of the second evaporator 2-3 to exchange heat with the raw water. Is called. Further, the water vapor evaporated by heating the raw water of the third evaporator 2-4 to the seventh evaporator 2-8 is also sent as a heat source to the heat exchanger of the next-stage evaporator, and heat exchange is performed with the raw water. Then, it is condensed to form distilled water, and finally stored in the distilled water tank 4.
The concentrated raw water in the concentrated water tank 5 is sent to the lower tank 3-1a of the condenser 3-1 of the cooling tower 3 through the pipe 27 by the concentrated raw water discharge pump 16, and further, the water spray nozzle 3-1c is supplied by the concentrated raw water circulation pump 17. And is sprayed as cooling water on the condensation (heat transfer) pipe 3-1b. The water vapor evaporated by heating the raw water in the eighth evaporator 2-9 at the final stage is sent to the condensing pipe 3-1b of the condenser 3-1 through the pipe 18, and between the concentrated raw water sprinkled with water. Heat exchange is performed and condensed to form distilled water, which is sent to the distilled water tank 4 through the pipe 19. The concentrated water overflowing the lower tank 3-1a is drained through the concentrated water discharge pipe 20.
The vacuum means 6 includes a gas / liquid separator 6-1 and a vacuum pump 6-2 connected to the gas / liquid separator 6-1. The gas-liquid separator 6-1 includes a pipe 7 through which the heat medium from the solar heat collector 1 passes through the pipes 21, 22, and 23, a deaeration chamber 2-1 of the evaporator 2, and a header 3 of the condenser 3-1. Connected to -1d. Thereby, as will be described in detail later, the evaporation space of the evaporator 2 and the condensation space and distilled water storage space communicating with the evaporation space can be reduced.
The distilled water Wb in the distilled water tank 4 is discharged by a distilled water pump 25. In FIG. 1, V1 to V8 are pulps.
FIG. 2 is a diagram showing details of a part of the solar heat collector 1 and the evaporator 2 of the desalination apparatus. As shown in the drawing, the heat medium steam Q1 heated by the plurality of solar heat collecting panels 1-1 to 1-6 of the solar heat collector 1 to become steam is a heat exchanger 2-1a in the deaeration chamber 2-1. And heat exchange is performed between the deaeration chamber 2-1 and the raw water W stored in the first evaporator 2-2 through the heat exchanger 2-2a of the first evaporator 2-2 to condense. The condensed heat medium Q2 is then stored in the buffer tank 9. The condensed heat medium Q2 is sent to the solar heat collecting panels 1-1 to 1-6 of the solar heat collector 1 through the heat medium circulation pump 26.
FIG. 3 is a diagram showing details of a part of the evaporator 2 of the desalination apparatus, the concentrated water tank 5 and the distilled water tank 4. The raw water preheating pipeline 12 is piped so as to pass through the raw water W stored in the eighth evaporator 2-9 to the second evaporator 2-3, and the raw water W passed through the raw water preheating pipeline 12 is It is preheated by heat exchange with raw water (concentrated raw water) W in the evaporator. The raw water W preheated through the raw water preheating conduit 12 is supplied to the deaeration chamber 2-1, and the raw water W overflowing the deaeration chamber 2-1, is an overflow pipe whose outlet is formed in a U shape. 13 to the first evaporator 2-2. The U-shaped portion 13a of the overflow pipe 13 corresponds to the differential pressure between the saturated vapor pressure corresponding to the highest temperature of the first evaporator 2-2 which is the uppermost evaporator and the highest ultimate vacuum of the vacuum means 6. A head to be used. The raw water W overflowed from the first evaporator 2-2 is supplied to the second evaporator 2-3 through the overflow pipe 13, and then flows down to the eighth evaporator 2-9 in the final stage. Each evaporator stores a predetermined amount of raw water.
The water vapor Wa evaporated in the first evaporator 2-2 is condensed by being exchanged with the raw water W through the heat exchanger 2-3a of the second evaporator 2-3 and becomes condensed water Wb. Together with the water vapor Wa generated in the second evaporator 2-3, it is sent to the heat exchanger 2-4a of the third evaporator 2-4 to exchange heat with the raw water. The condensed water Wb is sent to the heat exchanger 2-5a of the fourth evaporator 2-5 together with the water vapor Wa generated in the third evaporator 2-4. In this way, evaporation and condensation are repeated in order in each evaporator, and the distilled water Wb condensed in the heat exchanger 2-9a of the eighth evaporator 2-9 in the final stage is supplied to the distilled water tank 4.
FIG. 4 is a diagram showing details of a part of the vacuum means 6, the cooling tower 3, and the evaporator 2 of the desalination apparatus. As shown in the figure, the deaeration chamber 2-1, the pipe 7 through which the heat medium passes and the condenser 3-1 of the cooling tower 3 are connected to the vacuum pump 6-2 through the pipes 21, 22 and 23. Thereby, the internal space of the deaeration chamber 2-1, the piping 7, the internal space of the first evaporator 2-2 communicating with this, the header 3-1d of the cooling tower 3, and the condensing space in the condensing pipe 3-1b. The pressure can be reduced. In addition, the evaporation space and the condensation space of each evaporator after the 2nd evaporator 2-3 are connected by the vapor | steam piping 15, and can reduce pressure similarly. Exhaust is performed through an exhaust pipe 6-3 connected to the discharge port of the vacuum pump 6-2.
FIG. 5 is a diagram showing details of the distilled water tank 4, the concentrated water tank 5 and the cooling tower 3 of the desalination apparatus. The water vapor Wa evaporated by the eighth evaporator 2-9 of the evaporator 2 is sent to the condenser 3-1 through the pipe 18, and is concentrated from the water spray nozzle 3-1c while passing through the condensation pipe 3-1b. Cooling is performed by heat exchange between the raw water W and the air sent from the fan 3-2, and the condensed water Wb is sent to the distilled water tank 4. At this time, since the concentrated raw water W sprayed from the water spray nozzle 3-1c is cooled by the air sent from the fan 3-2, the water vapor Wa is efficiently condensed.
The desalination apparatus having the above configuration is provided with a raw water tank (not shown) that can always supply raw water at atmospheric pressure or higher. In the initial stage of installation of the desalination apparatus, a system in which a vacuum state is required during operation of the evaporator 2 or the like (the evaporation space of each evaporator of the evaporator 2, the condensation space communicating with the evaporation space, the condenser 3 of the cooling tower 3). 1 condensation space, distilled water tank 4 and concentrated water tank 5). Then, by opening the valve V8, a specified amount of raw water is introduced using the vacuum pressure. Since the desalination apparatus is always in a depressurized state after the start of operation, the valve V8 is automatically controlled to open and close so as to maintain the level of the raw water W of the first evaporator 2-2 according to the evaporation amount. Thus, the raw water W can be supplied into the desalination apparatus. The raw water W may be supplied using the raw water supply pump 11.
The solar heat collector 1 absorbs solar energy and heats the internal heat medium. The heat medium heated in the solar heat collector 1 whose inside is depressurized evaporates to become heat medium vapor Q1, and heat of the heat exchanger 2-1a and the first evaporator 2-2 in the deaeration chamber 2-1. Heat is exchanged between the raw water W introduced into the exchanger 2-2a and stored therein, the raw water W is heated, and the heat medium vapor Q1 is condensed to become a condensed heat medium Q2. Thus, the heat medium is naturally circulated by repeating evaporation and condensation, that is, circulated by a thermosyphon. Here, however, the heat recirculation pump 8 circulates the condensing heat medium Q2 by the heat collecting panel 1-1 of the solar heat collector. ˜1-n can be forcibly fed, and the level of the heat medium in the solar heat collector can be kept constant.
When the raw water W of the first evaporator 2-2 is heated by the heat medium vapor Q1, it evaporates and generates water vapor Wa. This water vapor Wa is supplied to the heat exchanger 2-3a of the second evaporator 2-3, heat exchange is performed with the raw water W stored in the second evaporator 2-3, and the raw water W At the same time, the heat is removed and condensed to form distilled water Wb. The water vapor Wa generated by heating the raw water W is transferred to the heat exchanger 2-4a of the third evaporator 2-4 and exchanges heat with the raw water W stored in the third evaporator 2-4. As the raw water W is heated, the heat is deprived and condensed to become distilled water Wb. The same process is repeated in this way.
The water vapor Wa evaporated in the seventh evaporator 2-8 in the previous stage of the eighth evaporator 2-9 is transferred to the heat exchanger 2-9a of the eighth evaporator 2-9, and heat exchange with the raw water W is performed. At the same time as the raw water W is heated, the heat is taken away and condensed to form distilled water, which is transferred to the distilled water tank 4. Further, the water vapor Wa evaporated by the eighth evaporator 2-9 in the final stage is transferred to the condenser 3-1 in the cooling tower 3, where the concentrated raw water W and the fan 3 sprayed from the water spray nozzle 3-1c. Heat is taken away and condensed by the air sent from -2. Then, it is transferred to the distilled water tank 4.
The raw water W supplied to the evaporator 2 passes through the raw water preheating conduit 12 passing through the raw water W in the eighth evaporator 2-9 to the second evaporator 2-3. The raw water W stored in the eighth evaporator 2-9 to the second evaporator 2-3 holds heat, and heat exchange is performed with the raw water W passing through the raw water preheating pipeline 12, The raw water W passing through the raw water preheating pipe 12 is preheated. Thereby, the heat which the concentration raw | natural water W in the 8th evaporator 2-9-the 2nd evaporator 2-3 hold | maintains is used effectively.
Furthermore, before supplying the non-condensable gas contained in the raw water W to the respective evaporators of the first evaporator 2-2 to the eighth evaporator 2-9, it is deaerated in the deaeration chamber 2-1. . When the non-condensable gas is not degassed, when the raw water is heated and evaporated in the evaporator, the non-condensable gas also enters the water vapor, and the steam between the water vapor and the raw water Wa in the heat exchanger in each evaporator. In this respect, the degassing of the non-condensable gas improves the distillation performance because heat transfer is hindered.
The water vapor Wa generated in each of the evaporators of the first evaporator 2-2 to the seventh evaporator 2-8 is condensed by heating the raw water W of the latter evaporator to be distilled water. Together with the water vapor Wa generated by heating the raw water W, it is further introduced into the heat exchanger of the subsequent evaporator. That is, the evaporators of the first evaporator 2-2 to the seventh evaporator 2-8 are connected to each other by the steam pipe 15 and the distilled water flow path 28 with a throttle through which distilled water Wb generated by condensing water vapor passes. It is communicated. Thereby, not only the condensation latent heat of the water vapor Wa but also the sensible heat of the distilled water Wb can be used effectively. Further, by providing the distilled water passage 28 with a restriction (orifice), a pressure difference is generated between the water vapor condensing space of the former stage evaporator and the water vapor condensing space of the latter stage evaporator. For this reason, the non-condensable gas does not stay in the former stage condenser but flows down to the latter stage evaporator together with the condensed water. The retention of the non-condensable gas in the evaporator inhibits heat transfer between the water vapor and the raw water Wa in the heat exchanger in each evaporator, but this can be prevented.
Each of the evaporators of the first evaporator 2-2 to the eighth evaporator 2-9 has an overflow pipe 13 disposed in each evaporator so that the raw water W to be supplied always maintains a specified amount. The concentrated raw water W that has overflowed through the overflow pipe 13 is introduced as raw water W into the subsequent evaporator. That is, each evaporator is sequentially supplied with concentrated raw water from the previous stage evaporator. Thereby, the raw | natural water with the high temperature level of the evaporator of a front | former stage becomes a heat source of the raw | natural water of the evaporator of a next | following stage, and becomes more efficient.
As described above, since the evaporators of the respective stages are in communication with each other, the raw water W can be continuously supplied, and the distilled water Wb and the concentrated raw water W can be continuously discharged. Therefore, since the amount of the raw water W in the evaporators of the first evaporator 2-2 to the eighth evaporator 2-9 is small, the desalination apparatus becomes compact, and the amount of heat of the retained raw water W is small. I'll do it. As a result, a large amount of distilled water Wb can be obtained with a small amount of heat supply, and an efficient operation becomes possible. And since the holding amount of the raw water W is small, the responsiveness by the solar radiation fluctuation | variation becomes quick and efficient driving | operation becomes possible.
Distilled water evaporated and condensed in each stage of the first evaporator 2-2 to the eighth evaporator 2-9 is brought together in the distilled water tank 4. Then, when the amount of distilled water in the distilled water tank 4 reaches a specified amount, or continuously, the distilled water pump 25 discharges / recovers out of the system at atmospheric pressure.
The concentrated raw water W that has passed without being evaporated by the evaporators of the first evaporator 2-2 to the eighth evaporator 2-9 reaches the concentrated water tank 5. When the amount of concentrated raw water in the concentrated water tank 5 reaches a specified amount or is continuously transferred to the lower tank 3-1a of the condenser 3-1 of the cooling tower 3 by the concentrated raw water discharge pump 16, the lower tank 3- The concentrated raw water 1a is supplied as cooling water to the water spray nozzle 3-1c by the concentrated raw water circulation pump 17, and sprinkled on the condensing pipe 3-1b.
The supply amount of the raw water W to the first evaporator 2-2 prevents the scaling in each evaporator, improves the maintainability, and improves the durability. The heat exchangers 2-2a to 2-9a in the evaporator do not always dry up from the raw water, and the concentration rate of the concentrated raw water W that passes through each evaporator and is transferred / discharged from the concentrated water tank 5 Is set to be equal to or less than the scale precipitation ratio (for example, 1.5 for seawater).
By installing the cooling tower 3 and keeping the temperature of the concentrated raw water W at the final stage constant around the outside air temperature, for example, an increase in the cooling water temperature of the cooling tank (fresh water) that becomes a problem in a batch-type desalination apparatus having a cooling tank Increase in the amount of heat held by the entire conversion apparatus) can be prevented, and a high yield of distilled water can be secured. Further, since the water vapor Wa evaporated by the eighth evaporator 2-9 in the final stage can be continuously cooled, continuous evaporation / condensation is possible. If a heat source other than the solar heat collector 1 can be secured, it can be continuously used for 24 hours. You can also drive.
Thus, the amount of retained water and the amount of retained heat are small, the cooling tower 3 is installed, and the temperature of the condensed water W in the final stage can be kept substantially constant at the outside air temperature (for example, the outside air temperature of 30 ° C.). By preventing the temperature rise of the condensed water and performing continuous operation, for example, the heat collection temperature (for example, heat medium steam inlet temperature 65 ° C.) collected by the normal solar heat collection panels 1-1 to 1-6 and From the raw water inlet temperature (for example, raw water inlet temperature 32 ° C.), in this embodiment, the evaporator 2 is used for the eight effects of the first evaporator 2-2 to the eighth evaporator 2-9. Thereby, solar energy with a low energy density can be used effectively eight times repeatedly.
In the batch-type desalination apparatus, every time the raw water is replaced, it is necessary to evacuate the apparatus from the atmospheric pressure, which requires a very large power consumption. In the above-described desalination apparatus according to the present invention, After evacuating from the atmospheric pressure in stages and reducing the entire system to a reduced pressure state, the raw water is continuously supplied and the operation is performed, and the accompanying non-condensable gas must be discharged. Since there is no need to evacuate from the atmospheric pressure, significant energy savings can be achieved.
When the sun goes down and there is no solar radiation, evaporation ends and the supply of raw water stops. That is, the desalination operation is stopped. On the next day, when the sun rises and evaporation in the evaporator 2 starts, the raw water W is newly supplied by the amount evaporated and the desalination cycle starts. For this reason, a desalination operation is possible by driving a pump or the like only when heat is supplied. In other words, when there is solar radiation and a heat source is supplied from the solar heat collector 1 to the evaporator 2, power can be generated at the same time, and by providing a solar power generation system that can supply the necessary power, self-contained desalination Become a device.
Further, if continuous operation is possible, a pump or the like may be driven only when a heat source is supplied from the solar heat collector 1 to the evaporator 2. In other words, if equipped with solar power generation equipment, when there is solar radiation and a heat source is supplied, power can be generated at the same time and necessary power can be supplied.
Electric equipment such as pumps can be operated intermittently and with time difference operation to reduce the required capacity at the peak of the photovoltaic power generation system, and the direct current electricity of the photovoltaic power generation system necessary for AC load equipment operation Since the capacity of the inverter to be converted into can be reduced, a compact solar power generation system can be constructed. If the system and the operation flow can be optimized, no power storage facility is required, and an even more compact, safe and maintenance-free power supply system can be constructed.
Since the vacuum pump requires a certain degree of high vacuum (for example, saturated vapor pressure of 31.8 mmHg at an outside air temperature of 30 ° C.) in order to repeatedly use solar energy having a low energy density, a conventional desalination apparatus. In this case, an oil rotary vacuum pump is used as the vacuum means. However, since water vapor is sucked during operation, water is mixed into the oil, which has been plagued by a decrease in the degree of vacuum achieved due to deterioration of the oil and a pump failure. It was. Here, water can be separated from oil by installing an oil / water separation tank and stopping a time device required for oil / water separation (for example, once a day for 8 hours at night). As a result, daily driving became possible. Furthermore, by using a scroll type vacuum pump that does not use oil, maintenance of oil is unnecessary, and 24-hour continuous operation is possible.
The evaporators of the first evaporator 2-2 to the eighth evaporator 2-9 constituting the evaporator 2 can secure a sufficiently wide evaporation area by using horizontal evaporators in which the heat transfer tubes are installed long in the horizontal direction. Since the steam speed can be suppressed, the amount of mist accompanying the water vapor Wa (that is, the minute droplets of raw water containing salt) can be reduced. In addition, the height from the vaporization surface of the water vapor in the evaporator to the vapor outlet of the evaporator is sufficient, and the mist accompanying the water vapor is collected in the flow path from the evaporator to the vapor outlet. By providing the baffle plate, high-quality distilled water could be obtained (5 μS / cm in this example).
In addition, when the evaporator has multiple effects like the first evaporator 2-2 to the eighth evaporator 2-9, it is made compact by adopting a vertical integrated structure, and the water vapor Wa, distilled water Wb and Unnecessary power is made unnecessary by concentrating the concentrated raw water W. Also, the on-site installation and construction is only the installation of the main body and the assembly of the gantry and panels, making the work easy.
FIG. 6 is a diagram showing another configuration example of the desalination apparatus according to the present invention. This desalination apparatus differs from the desalination apparatus shown in FIG. 1 in that the steam is condensed from the deaeration chamber 2-1 and the steam inlet side of the condenser 3-1, that is, from the eighth evaporator 2-9 to the condenser 3-1. The point is that the pipe 18 to be introduced into the pipe is communicated via a restriction 30 such as an orifice. This is because the non-condensable gas deaerated in the deaeration chamber 2-1 does not stay in the deaeration chamber by providing a pressure difference before and after the throttle 30, but flows down in the pipe 29, and the condenser 3-1, This is for facilitating the outflow through the pipe 23, the valve V3, and the vacuum means 6.
In the embodiment described above, an example in which the solar heat collector 1 is used as a heat source has been shown. However, the heat source is not limited to this, and an external heat source can be directly or indirectly supplied to the evaporator 2. That's fine.
In the desalination apparatus according to the embodiment described above, the following effects can be obtained.
(1) Depressurize the evaporation space of each evaporator of the evaporation device, the condensation space communicating with the evaporation space, and the distilled water storage space by a vacuum means, and the water vapor generated in the previous evaporator is transferred to the heat exchanger of the evaporator Introduced as a heat source, the generated steam and condensed distilled water are supplied to the heat exchanger of the next stage evaporator as the heat source, and multiple evaporators are used for multiple effects, so low energy density such as solar energy Fresh water can be efficiently obtained from raw water using the heat source.
(2) In addition, since each evaporator communicates with each other so that steam, distilled water and raw water exceeding a predetermined amount generated in each stage evaporator are supplied to the next stage evaporator, It is possible to continuously supply distilled water and concentrated raw water. In addition, since the amount of raw water held by each stage's evaporator is small, the equipment is compact, and the amount of heat held is small, so efficient desalination operation is possible with a large amount of distilled water with a small supply of heat. It becomes. In addition, since continuous operation is possible, vacuuming from the atmospheric pressure of the evaporation space of the evaporator that requires the most power in the desalination unit, the condensing space communicating therewith, the distilled water storage space, etc. Is no longer necessary.
(3) Further, the steam generated in the final stage evaporator is supplied to the condenser of the cooling tower, and the concentrated raw water in the concentrated water tank is used as cooling water in the condenser. The temperature can be kept close to the temperature, for example, preventing a decrease in afternoon distillation performance due to an increase in the cooling water temperature of the cooling tank (an increase in the amount of heat held by the entire apparatus), which is a problem in a batch-type desalination apparatus having a cooling tank. it can. In addition, since the water vapor evaporated in the final stage evaporator can be continuously condensed in the condenser, continuous evaporation and condensation are possible. If a heat source can be secured, the desalination operation can be performed continuously for 24 hours.
(4) In addition, the steam and condensed water generated in the previous stage evaporator are introduced into the heat exchanger of the evaporator as a heat source, and the generated steam and condensed distilled water are used as the heat source in the next stage evaporator. Therefore, not only the latent heat of condensation of the water vapor Wa but also the sensible heat of distilled water can be used effectively.
(5) Since each evaporator supplies raw water in excess of a predetermined amount to the next-stage evaporator, the high-temperature raw water in the previous-stage evaporator serves as a heat source for the next-stage evaporator, More efficient.
(6) Since the cooling tower cooperating with the condenser is provided, the concentrated raw water supplied as cooling water to the condenser can be forcibly cooled by the air sent from the fan provided in the cooling tower. The condensation efficiency of the vessel can be kept high and stable, and highly efficient desalination operation becomes possible.
(7) Since the condensation temperature can be kept low by using the cooling tower, the heat collection temperature in the solar heat collector is lowered, so the heat collection efficiency can be increased and the amount of heat collection can be increased, and an increase in the yield of fresh water can be expected. .
(8) The raw water supplied to the evaporator of the evaporator is preheated with the heat of at least some of the raw water of the evaporator (raw water already supplied into the evaporator and heated) through the raw water preheating pipe. The heat in the evaporator can be used effectively.
(9) Since the evaporator is provided with a deaeration chamber in front of the evaporator in the foremost stage, non-condensable gas that hinders heat transfer can be removed, distillation performance can be improved, and desalination can be achieved. The operation can be performed continuously rather than batchwise.
(10) By connecting the deaeration chamber and the water vapor inlet side of the condenser via a throttle, the non-condensable gas generated in the deaeration chamber is degassed from the condensation space of the condenser via a vacuum means. It becomes easy to discharge. Further, by providing a throttle also in the condensed water passage between the evaporators, non-condensable gas can be easily discharged, and heat exchange inhibition due to the gas remaining in the evaporator can be prevented. be able to.
(11) By providing a heat medium circulation means for circulating the condensation heat medium in the condensation heat medium flow path in the heat medium circulation circuit, even if the heat collection panel of the heat collector is installed at an angle with the largest amount of heat collection, In addition, the heat transfer surface of the heat collection panel can be filled with the heat medium even during the initial evaporation at sunrise or even if the liquid level of the heat medium fluctuates due to problems such as liquid pooling in the entire solar collector. In this way, it is possible to effectively use the total amount of solar radiation and to improve the follow-up to the evaporation of the heat medium with respect to intermittent solar radiation (irradiation fluctuation).
Applicability of invention
Unlike the conventional apparatus that uses fossil fuel or electric power as a heat source, the desalination apparatus according to the present invention can be used only in a limited place where the heat source equipment can be obtained. It can be installed in such places, and it is possible to desalinate by efficiently using low-density energy such as solar energy.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration example of a desalination apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing a detailed configuration example of a part of the solar heat collector and the evaporator of the desalination apparatus.
FIG. 3 is a diagram showing a detailed configuration example of a part of the evaporator of the desalination apparatus, a concentrated water tank, and a distilled water tank.
FIG. 4 is a diagram showing a detailed configuration example of part of the vacuum means, the cooling tower, and the evaporator of the desalination apparatus.
FIG. 5 is a diagram illustrating a detailed configuration example of a distilled water tank, a concentrated water tank, and a cooling tower of the desalination apparatus.
FIG. 6 is a diagram illustrating a configuration example of a desalination apparatus according to another embodiment.

Claims

A heat source,
An evaporator that includes a plurality of evaporators and generates water vapor from the raw water by heating the raw water with heat from the heat source;
A condenser for accepting and condensing water vapor generated from raw water heated in the evaporator from the last stage evaporator of the evaporator to form distilled water;
A vacuum device that depressurizes the space in the evaporator of the evaporator to below atmospheric pressure;
Have
The evaporator is configured such that its front-stage evaporator receives raw water from the outside, and each evaporator is connected to flow a predetermined amount of raw water down to the next-stage evaporator, and Heat from the heat source is supplied to the heat exchanger of the previous stage evaporator, and steam generated from the raw water in the frontmost heat exchanger is supplied to the heat exchanger of the next stage evaporator as a heat source, The supplied water vapor is condensed by heat exchange with the raw water in the next-stage evaporator, and the water vapor generated from the raw water by the heat exchange is further transferred to the heat exchanger of the next-stage evaporator. In the following evaporator, the same heating source is supplied, and the water vapor generated in the last stage evaporator is supplied to the condenser to be condensed into distilled water. Distillation discharged from the last stage evaporator Is taken out as fresh water with,
The vacuum device is configured to depressurize the evaporation space of each evaporator, the condensation space communicating with the evaporation space, and the distilled water storage space;
The desalination apparatus characterized in that the concentrated raw water discharged from the last stage evaporator is used as cooling water for the condenser .

The desalination apparatus according to claim 1 ,
The heat source is a solar heat collector that heats a heat medium by solar energy, and the heat medium vapor of the solar heat collector is supplied to the heat exchanger of the front-stage evaporator as a heat source. Desalination equipment.

The desalination apparatus according to claim 1 or 2 ,
The evaporator has a storage chamber for receiving raw water, and the raw water supplied to the foremost evaporator is passed through a raw water preheating conduit passing through the storage chamber of at least some of the evaporators. The desalination apparatus, wherein the desalination apparatus is supplied to the foremost evaporator.

The desalination apparatus according to any one of claims 1 to 3 ,
The evaporator has a deaeration chamber disposed in front of the front-stage evaporator, the deaeration chamber contains raw water to be supplied, is heated by heat from the heat source, and is contained in the raw water The desalination apparatus is characterized in that the degassed gas is degassed and the degassed raw water is supplied to the foremost evaporator.

The desalination apparatus according to any one of claims 1 to 4 ,
There is a condensed water passage for supplying the condensed water generated as a heating source in one evaporator and condensed by heat exchange to the next-stage evaporator as a heating source, and the passage is provided with a throttle. A desalination apparatus characterized in that a differential pressure is generated before and after the throttle.

The desalination apparatus according to claim 4,
The evaporator is connected in a multiple utility relationship ;
A vacuum apparatus that depressurizes the deaeration chamber to below atmospheric pressure and discharges non-condensable gas generated by heating the raw water in the deaeration chamber;
A desalination apparatus comprising:

The desalination apparatus according to claim 6 ,
The vacuum device is configured to depressurize the condensing space of the condenser and the evaporating space of the evaporator communicating with the condensing space, and switching between the depressurization and the depressurizing chamber. A desalination apparatus characterized by that.

In the desalination apparatus of Claim 6 or 7 ,
The degassing chamber, desalination apparatus characterized by via steam inlet side of the condenser is connected to the vacuum device.

The desalination apparatus according to claim 6 , 7 or 8 ,
The evaporators are stacked one above the other,
The deaeration chamber is set on the uppermost evaporator,
The deaeration chamber and the evaporator have a storage tank for storing raw water,
The raw water stored in each storage tank overflows from the storage tank and flows down to the storage tank of the evaporator at the lower stage.
The raw water overflowing from the storage tank of the deaeration chamber is made to flow down to the storage tank of the uppermost evaporator through a pipe line having a U-shaped pipe part,
The U-shaped tube portion has a head corresponding to the differential pressure between the saturated vapor pressure at the highest temperature in the uppermost evaporator and the highest reduced pressure applied to the deaeration chamber by the vacuum device. A desalination apparatus characterized by comprising:

The desalination apparatus according to claim 9 ,
The heat source is a solar heat collector that heats a heat medium by solar energy, and heat exchange between the deaeration chamber of the evaporator and the uppermost evaporator is performed using the heat medium vapor from the solar heat collector as a heat source. A desalination apparatus, characterized in that the condensed heat medium that is supplied to the condenser and condensed is returned to the solar heat collector.

In the desalination apparatus of Claim 10,
The heat source is a solar heat collector having a heat collection panel that collects solar heat to heat the heat medium and generate steam of the heat medium ,
The evaporator has a heat exchanger for exchanging heat between the heating medium and raw water ,
The heat medium condensed by heat exchange with the heat medium supply pipe which supplies the heat medium made into steam with the solar heat collector to the heat exchanger of the evaporator and the raw water with the heat exchanger A heat medium return pipe for returning to the heater is provided, and the heat medium is circulated by a thermosiphon system by repeatedly evaporating the heat medium in the solar heat collector and condensing in the heat exchanger. a heat medium circulation circuit, provided on the heating medium return conduit, the heat medium circulation circuit having a pump for feeding towards the condensation heat medium in the same conduit to the solar heat collector,
Furthermore , the desalination apparatus characterized by having.

The desalination apparatus according to claim 11 ,
A desalination apparatus comprising a buffer tank for storing a condensed heat medium upstream of the pump in the heat medium return pipe.

The desalination apparatus according to claim 11 or 12 ,
2. The desalination apparatus according to claim 1, wherein the pump has a capacity capable of supplying at least the amount of heat medium that the solar heat collector evaporates during maximum solar radiation to the solar heat collector.

The desalination apparatus according to claim 1,
A cooling device for introducing raw water concentrated by generating water vapor in the evaporator into the condenser and using it as cooling water;
A desalination apparatus comprising:

The desalination apparatus according to claim 14 ,
The desalination apparatus, wherein the cooling device has a blower fan, and the concentrated raw water is cooled by the blower fan and used as cooling water for the condenser.

The desalination apparatus according to claim 14 or 15 ,
The evaporator has a heat exchanger;
The heat source supply device is a solar heat collector that heats the heat medium by solar energy,
The desalination apparatus according to claim 1, wherein the heat exchanger receives heated heat-medium vapor and performs heat exchange with raw water.

The desalination apparatus according to claim 14 , 15 or 16 ,
The evaporator includes a plurality of evaporators stacked in multiple stages,
Each evaporator has the heat exchanger,
These evaporators are connected to a multi-effect relationship designed to send water vapor from raw water generated in each evaporator as a heating source to the lower evaporator,
The desalination apparatus characterized in that the cooling apparatus introduces the concentrated raw water discharged from the lowermost evaporator into the condenser and uses it as cooling water.