JP4010185B2

JP4010185B2 - High pressure hydrogen production method and apparatus

Info

Publication number: JP4010185B2
Application number: JP2002153961A
Authority: JP
Inventors: 宙幸原田
Original assignee: Mitsubishi Corp
Current assignee: Mitsubishi Corp
Priority date: 2002-05-28
Filing date: 2002-05-28
Publication date: 2007-11-21
Anticipated expiration: 2022-05-28
Also published as: JP2003342773A

Description

【０００１】
【発明の属する技術分野】
この発明は、ガス圧縮機を用いることなく、固体高分子電解質膜（ＰＥＭ）を用いて、純水の電気分解だけで高圧の水素、すなわち圧縮水素ガスを発生する高圧水素製造装置に関するものであって、水素クリーンエネルギー関連技術に属するものである。
【０００２】
【従来の技術】
現在エネルギーの主流となっている石炭や石油などの化石燃料は、その使用に伴って排出される二酸化炭素が地球温暖化の原因とされ、加えて、化石燃料の燃焼で排出される窒素酸化物やイオウ酸化物が人の健康を損ね、酸性雨を降らせたりする原因ともなっているとともに、その埋蔵量は無限ではなく、早晩、枯渇するおそれがある等の多くの問題を有している。
【０００３】
これらの問題を解決するため、再生可能で、クリーンな自然エネルギーによって、化石燃料を代替するための技術開発が求められている。そのなかでも、太陽エネルギーは、地球が受ける１時間分のエネルギーが、人類が今日消費している１年分以上のエネルギーに匹敵するもので、太陽エネルギーだけで、人類のエネルギー需要を賄うことも夢ではないものである。
【０００４】
また、自然エネルギーの利用方法としては、太陽光発電や風力発電等が良く知られているように、自然エネルギーは、一般に、電力として取り出され利用されているが、電力は、そのままでは、貯蔵したり、持ち運んだりすることができないので、電池に充電して貯蔵して利用する方法が行われているものの、電池は、きわめて重く、自己放電するので、使用しなくても消耗する等の問題を有している。
【０００５】
そのため、自然エネルギーで得た電力を水電解によって、クリーンな水素エネルギーに効率よく変換し、水素をエネルギーとして使用する水素経済社会への移行が検討されている。さらに、水素を燃料とする燃料電池（ＰＥＦＣ）の開発が盛んに進められ、これを自動車や家庭用の自家発電に広く使用することが検討されているもので、水素経済社会への移行のため、自然エネルギーで効率よく水素を製造することが求められている。
【０００６】
このような要望を受けて、プロトン（水素イオン）伝導性を有する固体高分子電解質膜（以下、ＰＥＭという。）によって、純水を直接電気分解し、水素と酸素にするＰＥＭ水電解が効率よく水素を製造する方法として注目されている。
このＰＥＭ水電解は、変動への追随性に欠け、起動停止が自由に行えないアルカリ水電解とは異なり、起動停止が自由に行えるという特長を有しているため、定常性に乏しい自然エネルギーから得た、変動の激しい電力を水素に変換する手法として最適なものである。
【０００７】
かくして得られた水素を、エネルギーとして利用する際の最大の課題は、気体である水素を如何にして安全に、しかもコンパクトにして持ち運び（輸送）したり、貯蔵したりするかにあるので、気体である水素を、液体水素にすることや吸蔵合金に吸蔵させる手法が検討されてきたが、最近では、高圧水素の安全性が見直されて、水素を３５０気圧又はそれ以上の高圧に圧縮した圧縮水素として、ボンベ等に充填して貯蔵及び輸送する方法が採用される機会が増え、水素経済社会を構成する技術として、広く用いられるようになってきている。
【０００８】
水の電気分解は、それ自身で高圧の水素及び酸素を発生できる昇圧能力を有しているもので、原理的には、コンプレッサー等の昇圧装置を用いないで、電気分解だけで千気圧以上の高圧水素を発生することも夢ではなく、しかも、機械的に昇圧する場合に比べて可動部が無いため、定期的に点検し、消耗部品を取替える等の保守作業の必要がなく、昇圧効率が良いので動力費も少なくて済む等多くの利点を有している。
【０００９】
しかしながら、ＰＥＭを用いた水電解セルによる電気分解では、現状の水電解セルの耐圧が低いため、数気圧〜数１０気圧程度の水素や酸素の発生がせいぜいで、エネルギー利用で必要とされる３５０気圧又はそれ以上の高圧の水素を発生することはできず、しかも、このような高い圧力の昇圧装置は、今日現在、それ自身も開発テーマとされているもので、電気分解だけで高圧水素を発生できる高圧水素製造装置の出現が待たれていた。
【００１０】
この問題を最初に解決した特許第３，２２０，６０７号（米国特許５，６９０，７９７号）は、水電解セルを、純水と酸素を貯留する高圧容器内の純水中に配置して水電解すると、水電解セルに作用する圧力は、発生する水素と酸素の差圧のみであることに着目し、水素と酸素の圧力を等しくなるように制御することで、耐圧の低い水電解セルを使用しても、水電解セルの耐圧を遥かに超える、高圧の水素及び酸素を発生できるようにしたものである。
【００１１】
しかしながら、この発明においては、水電解セルが純水中に浸漬配置されているので、純水の水質が低下して比抵抗が低下すると、水電解セルの電極間での漏電や電解腐食の問題が発生するため、エネルギー利用で必要とされる数１００気圧以上の高圧水素を発生させることが容易であるとは云えないものであった。
【００１２】
特に、純水は、温度の上昇により比抵抗が低下するが、それに加えて、純水に対する容器壁等の溶出が早くなるため、常時、イオン交換樹脂で純水を再生する必要があるが、処理される純水が高圧であると、イオン交換樹脂粒が破壊するということからも、発生させる圧力には限界があり、水素のエネルギー利用で必要とする高圧水素発生は困難であった。
【００１３】
このような問題を防ぐため、水電解セルを絶縁性液体が充満された高圧容器内に収納するという提案（特開２００１−１３０９０１号公報）がなされたが、絶縁性液体として実用的なものが現状では見当たらず、実用性に乏しいことが分かった。
【００１４】
例えば、絶縁性液体としてのＰＣＢは難燃性で、性能的には優れているが、公害等の問題から製造も使用も禁止され、現在、使用できる絶縁油は、全て、可燃性で、酸素が漏洩すると爆発する危険性があるので、結局、純水が絶縁性液体として優れているが、純水には、先に述べたように比抵抗の経時変化等の問題があり、その使用は困難である。
【００１５】
これらの問題を解決するものとして、先に、発明者は特願２００２−０１９７１３号公報で、水電解セルを、発生した水素の貯留部を兼ねる高圧容器内に配置する、すなわち、水電解セルを高圧水素中に配置すると共に、水電解セルを配置した高圧容器の圧力と電解用純水と発生した酸素の貯留部を兼ねる高圧容器の圧力との差圧を水電解セルの耐圧以下の圧力に調整する、という提案を行なった。
【００１６】
この提案は、先の特許第３，２２０，６０７号などで問題とされた、電解腐食や純水比抵抗低下の問題を一気に解決しただけでなく、水電解セルが破損しても純水が酸素と水素を隔離する働きをも兼ねて、爆鳴気の生ずることを防止できる等、安全性を飛躍的に進歩させたものである。
【００１７】
【発明が解決しようとする課題】
しかしながら、この提案においては、水電解セルに作用する力を水電解セルの耐圧以内にするために、発生する水素と酸素の差圧を水電解セルの耐圧以内に制御するのであるが、水電解セルの耐圧は一定であるので、発生する水素及び酸素の圧力が増せば増すほど、高い制御精度が求められることになり、圧力制御が、結局は、この提案による発生水素圧力の制限要因となることになる。
【００１８】
すなわち、水電解セルの許容耐圧が４気圧で、水素及び酸素の発生圧力が１０気圧の場合は、圧力制御精度は４／１０、換言すると、４０％以内であればよいので、通常の圧力制御手法により、水電解セルを破損させることなく対応が可能であるが、この水電解セルを用いて４００気圧の水素と酸素を発生する場合を考えると、４／４００、すなわち、１％以上の精密高精度圧力制御が求められ、通常の圧力制御手法では達成が困難で、しかも、今後、必要とされる圧力は、さらに高くなるので、さらに厳しい圧力制御精度が要求されるので、通常の圧力制御手法では不可能に近く、新しい手法が求められている。
【００１９】
さらに、この提案における方法では、純水の液面を測定する水面計にも問題が生じる。
すなわち、電気分解の原料となる純水は、水電解で発生した酸素と共に高圧容器に貯留されるが、標準状態（温度０℃；１気圧）の酸素の密度は、１．４２９×１０^−３ｇ／ｃｃで、非常に軽く、容器中では、水が下に、酸素が上になる常識が通用するが、酸素を理想気体と仮定すると、１／１．４２９×１０^−３＝７００から、７００気圧の酸素は水と同じ密度になる。
このことは、７００気圧以上では、水が酸素に浮くことになり、ガスは水より軽いとする通常の経験則が通用しなくなる。
【００２０】
幸いなことに、このような密度の逆転は、酸素分子の大きさや分子間力を考慮すると、１０００気圧以上でないと起こらないが、従来広く採用されているフロート式の水面計では、水と酸素の密度差が小さくなると、水流等によりその動作が不安定となり、水面を正確に検知できなくなる。
これに加えて、フロート式水面計に使用するフロートは、見かけの比重を１以下に軽く製造しなければならないので、耐圧性に問題があり、水素のエネルギー利用で必要とされるような、圧力に充分耐えうるフロートの製作が困難とされているので、このような問題が解決でき、高圧下で安定に作動する水面計の開発が先の提案の方法を幅広く、かつ安定に実施するために、強く求められている。
【００２１】
以上のような問題、特に圧力制御精度の問題を解決しない限り、水の電気分解だけで、水素のエネルギー利用で必要とされる３５０気圧又はそれ以上の高圧の水素を安定に製造することは不可能とも言えるもので、発明者は、以上のような問題を解決し、コンプレッサー等の機械的手段を用いないで、エネルギーとして使用するのに必要とされている３５０気圧又はそれ以上の高圧の水素を、水の電気分解だけで安定に、しかも、安全に発生できる高圧水素製造装置を提供することを目的として検討を行ったのである。
【００２２】
その結果、発明者は、発生した水素や酸素を貯留する水素高圧容器、酸素高圧容器のいずれの容器内にも、純水が存在することに着目し、純水を圧力の高い方から低い方に移動させて差圧を解消する方法によって、上記圧力制御の問題が解決でき、また、酸素等の気体と純水との電気伝導率特性が大きく異なっていることを利用して、水面を検知することにより、水面計の問題を解消できることを見出して、この発明を完成させたのである。
【００２３】
【課題を解決するための手段】
すなわち、この発明の請求項１に記載の高圧水素製造方法は、
固体高分子電解質膜よりなる水電解セルによって、純水を電気分解して水素を発生させるに際し、
発生させた水素を貯留する水素高圧容器と、酸素を貯留する酸素高圧容器の圧力差を、それら容器内に存在する純水を連通させる配管を用いて、前記各容器内に存在する純水を、いずれか一方側に移動させることによって調整すること
を特徴とするものである。
【００２４】
また、この発明の請求項２に記載の高圧水素製造方法は、
固体高分子電解質膜からなる水電解セルによって、純水を電気分解して水素を発生させるに際し、
発生させた水素を貯留する水素高圧容器と、酸素を貯留する酸素高圧容器の圧力差を、前記各容器の水素圧、酸素圧の調整、及びそれら容器内に存在する純水を連通させる配管を用いて、前記各容器内に存在する純水を、いずれか一方側に移動させることによって制御すること
を特徴とするものである。
【００２５】
また、この発明の請求項３に記載の発明は、
請求項１又は２に記載の高圧水素製造方法において、
前記圧力差は、
水電解セルの耐圧以下に抑えること
を特徴とするものである。
【００２６】
また、この発明の請求項４に記載の発明は、
請求項１又は２に記載の高圧水素製造方法において、
前記純水の移動は、
水素高圧容器と酸素高圧容器を結合する純水配管に接続され、かつ各容器内に設けられた開放弁の操作によって行われること
を特徴とするものである。
【００２７】
また、この発明の請求項５に記載の発明は、
請求項４に記載の高圧水素製造方法において、
前記開放弁の操作は、
開放弁を容器内の純水中に浸漬させた状態で行なうこと
を特徴とするものである。
【００２８】
また、この発明の請求項６に記載の発明は、
請求項１又は２に記載の高圧水素製造方法において、
前記純水の移動は、
水素高圧容器と酸素高圧容器を結合する純水配管に設けられた圧力調整器によって、自動的に行われること
を特徴とするものである。
【００２９】
また、この発明の請求項７に記載の発明は、
請求項１又は２に記載の高圧水素製造方法において、
前記純水の移動は、
水素高圧容器と酸素高圧容器を結合する純水配管に設けられた弁の開閉操作によって行われること
を特徴とするものである。
【００３０】
また、この発明の請求項８に記載の発明は、
請求項１又は２に記載の高圧水素製造方法において、
前記水素高圧容器内に貯留する純水容積を、酸素高圧容器内に貯留する酸素容積以上に、また、酸素高圧容器内に貯留する純水容積を、水素高圧容器内に貯留する水素容積以上に制御しながら行うこと
を特徴とする高圧水素製造方法である。
【００３１】
また、この発明の請求項９に記載の発明は、
請求項１又は２に記載の高圧水素製造方法において、
前記酸素高圧容器内に貯留する酸素量を、水素高圧容器内に貯留する水素量の４％以内に制御しながら行うこと
を特徴とする高圧水素製造方法である。
【００３２】
さらに、この発明の請求項１０に記載の発明は、
固体高分子電解質膜からなる水電解セル、発生する水素と水素に付随する純水を貯留する水素高圧容器、原料及び戻り純水と発生する酸素を貯留する酸素高圧容器、水素高圧容器内の純水と酸素高圧容器内の純水を連通する差圧調整用純水配管、及び水素高圧容器と酸素高圧容器内の水素と酸素の圧力差を感知し、その圧力差を制御するための差圧検知器を具備すること
を特徴とする高圧水素製造装置である。
【００３３】
また、この発明の請求項１１に記載の発明は、
固体高分子電解質膜からなる水電解セル、発生する水素と水素に付随する純水を貯留する水素高圧容器、原料純水と発生する酸素を貯留する酸素高圧容器、水素高圧容器内の純水と酸素高圧容器内の純水とを連通させる差圧調整用純水配管、及び純水配管に設けられ、水素高圧容器の純水と酸素高圧容器の純水との圧力差に応じて摺動する摺動子を内部に有する圧力調整器を具備すること
を特徴とする高圧水素製造装置である。
【００３４】
また、この発明の請求項１２に記載の発明は、
請求項１０又は１１に記載の高圧水素製造装置において、
前記水電解セルは、
水素高圧容器内又は純水酸素高圧容器内に設置されていること
を特徴とするものである。
【００３５】
また、この発明の請求項１３に記載の発明は、
請求項１０又は１１に記載の高圧水素製造装置において、
前記酸素高圧容器上方に高圧純水供給槽及び純水補給槽を具備し、それらの底部を接続する送水ポンプと、イオン交換樹脂筒と、フィルタを有する純水循環送り配管、高圧純水供給槽の上部と純水補給槽上部を接続する純水循環戻り配管、酸素高圧容器上部と高圧純水供給槽上部を接続する酸素供給配管、高圧純水供給槽底部と酸素高圧容器内を接続する純水注入配管が配置されている純水製造・供給システムを併せ具備すること
を特徴とする高圧水素製造装置である。
【００３６】
また、この発明の請求項１４に記載の発明は、
請求項１０に記載の高圧水素製造装置において、
前記水素高圧容器内の純水と酸素高圧容器内の純水を連通する純水配管は、
水素高圧容器内に開放弁を設けた配管と、酸素高圧容器内に開放弁を設けた配管の２本からなること
を特徴とするものである。
【００３７】
また、この発明の請求項１５に記載の発明は、
請求項１４に記載の高圧水素製造装置において、
前記開放弁は、
正面視が三角形状の放出口を有していること
を特徴とするものである。
【００３８】
また、この発明の請求項１６に記載の発明は、
請求項１０に記載の高圧水素製造装置において、
前記差圧検知器は、
水素高圧容器又は酸素高圧容器の圧力で、軸方向に伸縮するベローズで両端が封止され、内部に非活性流体が充満された非磁性材料の円筒と、前記円筒の内面に密着して移動自在に設けられた内部磁性体と、外面に密着して移動自在に設けられた外部磁性体からなる装置主体と、ベローズの伸縮により変化した前記外部磁性体の位置に基づいて差圧を検知する検出器から構成されるものであること
を特徴とするものである。
【００３９】
また、この発明の請求項１７に記載の発明は、
請求項１６に記載の高圧水素製造装置において、
前記差圧検出器は、
外部磁性体に連動して動く遮光板と、遮光板で遮光される開口部を有する表示板と、開口部を透過した透過光量を電気信号に変換する光電計から構成されるものであること
を特徴とするものである。
【００４０】
また、この発明の請求項１８に記載の発明は、
請求項１６に記載の高圧水素製造装置において、
前記差圧検出器は、
外部磁性体に連動して電気抵抗体上を摺動する摺動子を構成要素に有するものであること
を特徴とするものである。
【００４１】
また、この発明の請求項１９に記載の発明は、
請求項１１に記載の高圧水素製造装置において、
前記圧力調整器は、
一端部が水素高圧容器内純水に連通し、他端部が酸素高圧容器内純水に連通する非磁性材料で作られた中空円筒、両純水を遮断すると共に、中空円筒の内面に密着して滑動する磁性材料で作られた内部滑動子及び中空円筒の外面に密着して滑動する磁性材料で作られた外部滑動子からなる装置主体と、前記外部滑動子の位置を検出する位置検出器から構成されるものであること
を特徴とするものである。
【００４２】
また、この発明の請求項２０に記載の発明は、
請求項１９に記載の高圧水素製造装置において、
前記中空円筒は、
両端部にスプリングを有すると共に、内部滑動子が、端部まで滑動したとき、純水を流通させる流路を両端に有するものであること
を特徴とするものである。
【００４３】
また、この発明の請求項２１に記載の発明は、
請求項１９に記載の高圧水素製造装置において、
前記中空円筒は、
両端部にスプリングを有すると共に、内部滑動子が、端部まで滑動したときに作動する、純水を流通させる配管に設けた遮断弁を開閉するスイッチを両端に有するものである
ことを特徴とするものである。
【００４４】
また、この発明の請求２２に記載の発明は、
請求項１９に記載の高圧水素製造装置において、
前記中空円筒は、
水素高圧容器内に貯留される水素量と、酸素高圧容器内に貯留される酸素量とのどちらかの少ないほうの容積と等量、もしくはそれ以下の実質容積を有するものであること
を特徴とするものである。
【００４５】
また、この発明の請求項２３に記載の発明は、
請求項１０乃至２２のいずれかに記載の高圧水素製造装置において、
中心電極と、中心電極を中心にした円筒状電極とを構成要素とする水面計を併せ有すること
を特徴とする高圧水素製造装置である。
【００４６】
また、この発明の請求項２４に記載の発明は、
請求項２３に記載の高圧水素製造装置において、
前記水面計は、
棒状の中心電極の外側に外部電極を同心円上に配置したメイン電極と、先端部以外を電気絶縁性円筒で覆った棒状の中心電極の外側に外部電極を同心円上に配置したサブ電極を有すること
を特徴とするものである。
【００４７】
さらにまた、この発明の請求項２５に記載の発明は、
請求項１０乃至２３のいずれかに記載の高圧水素製造装置において、
水素高圧容器に常時開型水素緊急放出弁、純水酸素高圧容器に常時開型酸素緊急放出弁、水電解セルの電源に緊急電源遮断スイッチとを併せ設けたこと
を特徴とする高圧水素製造装置である。
【００４８】
【発明の実施の形態】
以下、この発明の高圧水素製造方法とその装置の好適な実施の形態を、添付の図面に基づいて説明する。
【００４９】
図１は、この発明の高圧水素製造装置の一実施例を示す概略説明図であって、この高圧水素製造装置は、基本的には、水電解セル１が発生した水素雰囲気中に収まるように配設された水素高圧容器２と、電解される原料純水と、戻り純水及び発生した酸素を貯留する酸素高圧容器６２、水素高圧容器２内の純水と、酸素高圧容器６２内の純水を連通する純水配管１６ａ，１６ｂ及び水素高圧容器２と酸素高圧容器６２内の水素と酸素の圧力差を感知し、その圧力差を制御するための差圧検知器５３とで構成されるものである。
【００５０】
図１に示される高圧水素製造装置において、電解される純水は、酸素高圧容器６２からポンプ７により水電解セル１に送られ、電源６１から水電解に必要な電力を供給すると、純水が電気分解して、水素放出口３から水素と純水が水素高圧容器２内に放出され、発生した酸素と未分解の純水は、戻り管４を通って酸素高圧容器６２に送られる。
【００５１】
水素高圧容器２内及び酸素高圧容器６２内は、それぞれ発生した水素及び酸素により昇圧し、所定の圧力、例えば、４００気圧の状態になるが、水素の需要の無い時は、この状態で電解を中止して待機しているもので、水素を必要とする時は、弁５７を開放し、ニードル弁５６を徐々に開くことによって、水素供給口５５から水素が供給される。
【００５２】
水素の供給によって、水素高圧容器２内の圧力が低下することが圧力計５４で計測されると、圧力計５４に連動する制御装置（図示せず）からの指令で、電源６１から水電解セル１に電力の供給が再開され、圧力計５４の圧力が再び元の値に戻るまで電力が供給される。
【００５３】
圧力計５４の圧力が回復すると、ニードル弁５６の開度をさらに増し、圧力計５４の圧力が回復するまで電源６１の電力を増す。このようにして、ニードル弁５６の開度を増しても圧力が低下しなくなるか、または電源６１の供給電力が許容最高電力になれば、その状態を維持して水素の供給を続ける。
【００５４】
純水の電解で水素と共に、水電解セル１で発生する酸素は、酸素高圧容器６２上部の酸素貯留部５２に溜められる。
【００５５】
この酸素貯留部５２に溜められた酸素の圧力と、水素高圧容器２内の水素の圧力との差圧は、電解中及び水素供給中、下記に具体例の一例が示される差圧検知器５３で計測され、この計測信号により、通常、制御装置（図示せず）が弁４４の開閉及びニードル弁４３の開度を制御し、差圧検知器５３からの差圧信号が０になるように酸素放出口４５からの酸素放出量を制御する。
【００５６】
このようにして、水素高圧容器２内の圧力と、純水酸素高圧容器６２内の圧力が等しいように制御されながら、電解が行われ、水素供給口５５からの水素供給が行われる。
【００５７】
従来の高圧水素製造装置においては、上記のように、酸素高圧容器６２と水素高圧容器２の差圧は、酸素及び水素、特に酸素の放出により調整しているが、一般に、水電解セル１の耐圧から期待できる許容圧力は、４気圧程度であるので、前記したように、この水電解セル１を用いて、例えば、４００気圧の水素と酸素を発生させる場合は、１％以上の高精度の圧力制御が求めらる。
【００５８】
そのため、この発明においては、水素供給口５５に接続され、水素供給を受けている装置の水素消費量の変動や、電源６１の供給電力の変動等による圧力制御乱れにより、差圧が水電解セル１の許容耐圧を超える、すなわち、圧力制御乱れによる水電解セル１の許容耐圧以上の差圧発生を回避するため、水素高圧容器２内の純水と、酸素高圧容器６２内の純水を連通する純水配管16ａ，１６ｂと、純水配管16ａ，１６ｂにそれぞれ接続され、差圧に基づいて作動する開放弁８及び１７が設けられている。
【００５９】
したがって、水素高圧容器２内の水素圧力が、酸素高圧容器６２内の酸素圧力より低くなって、その差圧が、セル１の許容圧力値を超えるおそれが出てきた場合には、開放弁８から酸素高圧容器６２内の純水が、水素高圧容器２内に放出され、これにより酸素高圧容器６２内の純水容積が減少し、酸素貯留部５２の酸素容積が増え、酸素高圧容器６２内の酸素圧力が低下すると共に、水素高圧容器２内の圧力は高くなって、許容耐圧以下に差圧が維持される。
【００６０】
その際、水素高圧容器２内の水素容積が２０Ｌ、酸素高圧容器６２内の酸素容積が０．４Ｌ（水素の２％）とし、発生圧力が４００気圧とすると、０．４Ｌの１％である４ｃｃの純水が、酸素高圧容器６２から流出し、水素高圧容器２に流入し、酸素圧力は、４００気圧の１％である４気圧減少し、水素圧力は、０．０８気圧増加するので、合計で４．０８気圧の差圧を、僅か４ｃｃの純水の流出入で効率よく解消させることができる。
【００６１】
酸素高圧容器６２内の水面５１を制御することは、特に３５０気圧以上での水素発生に際しては重要で、この発明においては、後述するような水面計５０を酸素高圧容器６２内に配置し、常時水面５１を計測し、水面５１が所定の位置より低下すると、弁３８を開いて高圧純水供給槽４１内の純水を、その重力を利用して酸素高圧容器６２内に流し込み、高圧純水供給槽４１から酸素高圧容器６２に純水が流入すると、同時に同じ量の酸素が、弁３９を通って高圧純水供給槽４１に流れ込む。
【００６２】
高圧純水供給槽４１内の純水を、酸素高圧容器６２内に重力を利用して流し込むには、高圧純水供給槽４１を酸素高圧容器６２より高い位置に、また、高圧純水供給槽４１に純水を補給する純水補給槽４０も、同位置又はさらに高い位置に設置することが肝要である。
【００６３】
高圧純水供給槽４１への純水補給は、弁３８と３９を閉止して、弁３６と３７を開放して行われる。すなわち、弁３８と３９を閉にして酸素高圧容器６２と分離し、弁３６及び３７を開にして、純水補給槽４０の純水を、ポンプ３２によりイオン交換樹脂筒３３及びフィルタ３４を通して行う。
【００６４】
その際、純水の比抵抗が比抵抗計３５により計測され、比抵抗値が低いと、水電解セル１の触媒電極等が被毒し、水電解セル１の寿命を縮めるので、純水を循環させて、比抵抗値が所定値以上に高くなるまで、イオン交換樹脂筒３３を複数回通過させ、イオン交換処理を行う。
【００６５】
純水補給槽４０が高圧純水供給槽４１の上方に設置されていると、高圧純水供給槽４１内は、純水で満たされ、気泡等も除去できるので、弁３６及び３７を閉止して、弁３８及び３９を開にした時の圧力変動は、純水の体積変化だけで、圧力制御の面では、ほとんど無視できる。
【００６６】
ポンプ３２による純水の循環は、常圧で行われるので、ポンプ３２、イオン交換樹脂筒３３、フィルタ３４及び比抵抗計３５は、全て、常圧で動作する。
このポンプ３２による純水循環の終了は、比抵抗計３５により計測される純水比抵抗値により決められる。
【００６７】
また、高圧純水供給槽４１と同じ機能を有する予備槽を設けることによって、どちらか一方を常に待機させれば、酸素高圧容器６２への純水供給に滞りが生ずることはない。
【００６８】
酸素高圧容器６２内の純水は、水電解セル１に送られて水電解の原料となるので、長期に貯留して純水比抵抗が、例えば、６ＭΩ／ｃｍ^２以下というように、水質が低下すると、水電解セル１の触媒電極等が被毒し、水電解セル１の寿命を縮めることがあるので、酸素高圧容器６２内の純水の水質低下を防ぐためには、随時、純水の一部を新鮮な純水と交換することが望ましい。
【００６９】
酸素高圧容器６２内の純水の交換は、弁１８を開いて純水排出槽１９に純水酸素高圧容器６２内の純水を流し込み、弁１８を閉じ、弁２１を開き、純水排出槽１９内の純水を受水槽２３に排出し、その分の純水を、高圧純水供給槽４１から補給することで行われる。
【００７０】
その際、純水交換操作での圧力変動を少なくするため、純水排出槽１９の容積は、酸素貯留部５２の１％程度にすることがよく、純水の交換頻度は、純水の使用量にもよるが、１日当たり１０回程度（１０％程度）で問題ない。
【００７１】
水素高圧容器２には、発生した水素と共に、水電解セル１の陽極から陰極への浸透純水が水素放出口３から放出され、水素高圧容器２内の底部に溜まる。
【００７２】
この純水の貯留量は、酸素高圧容器６２の酸素貯留部５２容積の２倍程度以上にするのがよく、その量の制御は、水面計１０により水面９を検知し、所定量以上に純水が増えると、弁１１を開にして純水受槽１２に流し込む。純水受槽１２の容積は、弁１１を開にし、純水受槽１２に純水を流し込む操作での圧力変動が水電解セル１の耐圧で定まる許容耐圧以下になるように定める。
【００７３】
例えば、水素高圧容器２内の水素の最高発生圧を４００気圧、貯留される水素容積を２０リットル、水電解セル１の許容圧を４気圧とした場合、純水受槽１２の容積を０．２リットル（１％）以下にすると、弁１１を開にして純水を純水受槽１２に流入させる操作での水素圧力変動は、最大でも４００×１％＝４気圧となる。
【００７４】
その際、何らかの要因が重なって、この操作で４気圧以上の差圧が発生することがあっても、開放弁８及び１７の作用で、水電解セル１の耐圧の許容値を超える差圧は発生しない。
【００７５】
なお、図１において、５は水の電気分解で発生した熱を冷却するための熱交換器、６は水電解セル１に供給する純水を所望の温度にするための熱交換器、１３は電気抵抗式の水面計、１５は純水排出管、２０は電気式の水面計、２４はフロート式の水面計、２５は水供給口、２７はポンプ、２８はイオン交換筒、２９はフィルタ、３０は純水比抵抗を計測するための純水比抵抗計、３１はフロート式の水面計、４６は酸素緊急放出口、４７は酸素緊急放出弁、４８は圧力計、４９は酸素中の水素濃度を検知するガス漏洩検知器、５８は水素緊急放出弁、５９は水素緊急放出口、６０は水素中の酸素濃度を計測する漏洩検知器である。
【００７６】
図２は、この発明に使用する差圧検知器の一例を示す部分断面図で、図に示されるように、この差圧検知器５３は、水素高圧容器２又は酸素高圧容器６２の圧力で、軸方向に伸縮するベローズ106，107で両端が封止され、内部に非活性流体が充満された非磁性材料の円筒101と、円筒101の内面に密着して軸方向にスライド自在に設けられた内部磁性体104と、円筒101の外面に密着し、かつ前記内部磁性体104と連動し、軸方向にスライド自在に配置された外部磁性体105からなる装置主体100と、前記ベローズ106，107の伸縮によりスライド移動する外部磁性体105と連動して差圧を検知する検出器120から構成されている。
【００７７】
なお、この検出器120は、外部磁性体105に連動して動く遮光板119と、遮光板119で遮光される開口部117，118を有する表示板116と、開口部117，118を透過した透過光量を電気信号に変換する光電計（図示せず）から構成されるものである。
【００７８】
図２示される差圧検知器５３では、水素配管112で水素高圧容器２内の水素が水素圧力室110に送られ、酸素配管113から酸素高圧容器６２内の酸素が酸素圧力室111に送られると、それらの圧力が、各々、ベローズ106及び107に伝えられる。
【００７９】
ベローズ106と107及び円筒101内には、機械油等の流体が充満されているので、圧力を受けても体積が殆ど変化せず、ベローズ106及び107が水素配管112及び酸素配管113により送られる高圧の水素及び酸素から圧力を受けても、その圧力で押し潰されることはない。
【００８０】
水素配管112及び酸素配管113により送られる水素と酸素の圧力が等しい場合は、ベローズ106と107が水素圧力室110及び酸素圧力室111から押される力が等しいため、内部磁性体104は、円筒101の中央に停止した状態を維持する。
【００８１】
しかしながら、水素配管112で送られる水素の圧力が、酸素配管113で送られる酸素の圧力より高い場合は、その差圧によりスプリング114が伸び、スプリング115が縮み、差圧とスプリング114及び115の伸び縮みによる力がバランスする位置まで、酸素圧力室111側に内部磁性体105が固定棒102及び103で押されて移動する。
【００８２】
内部磁性体104と外部磁性体105は、互いに磁気力を及ぼしあって磁気結合しているので、内部磁性体104の移動に伴って外部磁性体105が移動し、外部磁性体105に固定されている遮光板119が移動し、酸素側の開口部118の一部を覆い、開口部117を透過する光量は変化しないが、開口部118を透過する光量が減少する。
【００８３】
逆に、水素配管112で送られる水素の圧力が、酸素配管113から送られる酸素の圧力より低い場合は、水素側の開口部117の一部が遮光板119で覆われ、開口部117を透過する光量が減少する。
【００８４】
したがって、開口部117及び118を透過する光量を計測することで、水素配管112で送られる水素の圧力と、酸素配管113から送られる酸素の圧力との差圧の大きさと、どちらが高くてどちらが低いかが分かるので、例えば、図１の弁４４とニードル弁４３の開閉を制御して、酸素の放出量を制御することにより、開口部117及び118を透過する光量に差が無いようにし、差圧を０にすることができる。
【００８５】
以上の説明においては、光量計測で内部磁性体104の位置を計測する手法を説明したが、計測はスライド抵抗を用いても行える。すなわち、外部磁性体105に摺動子を固定し、外部磁性体105と一体の滑動子の動きに合わせてスライド抵抗上を摺動子が動くようにすることで、内部磁性体104の移動量を計測することもできる。
【００８６】
図３は、この発明で用いた開放弁８及び１７の構造を示す断面図（ａ）と側面図（ｂ）であって、図示されるように、この開放弁８，１７は、円筒状の弁主体１３０に、純水放出のための放出口１３２を設けるとともに、その内部にシリンダー131と、このシリンダー131と連動するスプリング133とを設け、前記スプリング133を、その付勢力が調整可能なようにネジ135と固定ナット136で固定し、水素高圧容器２内又は酸素高圧容器６２内の純水を移動させる純水配管１６ａ又は１６ｂとの接続配管138と、通気口137を有するものである。
【００８７】
この開放弁８，１７は、固定ナット136を緩めてネジ頭134を回転させ、スプリング133の押える強さを調整することによって、接続配管138により伝えられた純水の圧力で押上げられるシリンダー131が、放出口132より上方に位置し、接続配管138の純水が放出口132より放出する圧力を、所望の圧力（セルの耐圧で定まる許容圧）に設定することが可能なもので、固定ナット136を締めて、設定が変わらないようにすることも可能なものである。
【００８８】
シリンダー131は、弁主体130が置かれている雰囲気の圧力が接続配管138内の純水圧力より高くなると、その差圧でスプリング133が縮み、シリンダー131が上方に移動を開始し、接続配管138内の純水の圧力がさらに増すと、シリンダー131が放出口132を越え、放出口132から接続配管138内の純水が放出されるため、接続配管138内の圧力が低下するものであるが、放出口132の形状を逆三角形の形状とすることで、放出される純水量は、差圧が少ない時は少なく、差圧が大きくなると多くなり、差圧が速やかに解消できる。
【００８９】
図４は、酸素等の気体と、純水との電気伝導率特性が大きく異なっていることを利用した水面計の断面図で、図１における水面計５０であり、棒状の中心電極150aと、この中心電極150aの外側に、同心円上に配置された外部電極150bとからなるメイン電極150と、先端部以外を電気絶縁性円筒で覆った棒状の中心電極151aと、この中心電極151aの外側に、同心円上に配置された外部電極151bとからなるサブ電極151とで構成されている。
【００９０】
なお、図中、152は純水水面、153a及び153bは通気口、154a及び154bは外部電極150b，151bの取付け部、155a及び155bは中心電極150a，150bの取付け部、156a及び156bは絶縁碍子、157a及び157bは外部電極150b，151bの取付け用の固定治具、158は取付け用のフランジ、159a及び159bは固定治具157a及び157bを固定するためのナット、160a及び160bは絶縁板、161a及び161bは座金、162a及び162bはリード線、163a及び163bは座金、164a及び164bは中心電極150a，150bを固定するためのナット、165a〜167bはＯリングである。
【００９１】
かかる構成の水面計５０において、中心電極150aと外部電極150bが純水中に浸漬されると、中心電極150aと外部電極150b間を浸漬している純水の抵抗が、リード線162aとアース間に、電気抵抗計を接続すると計測できるので、この抵抗値をＲｍとする。
【００９２】
一方、リード線162bとアース間の電気抵抗を計測すると、絶縁円筒168で覆われないで露出している中心電極150bの先端部と、外部電極151b間の純水の抵抗が計測できるので、この抵抗値をＲｒとする。
【００９３】
中心電極151aが、絶縁円筒168で覆われていない先端部の長さをＬｒとし、中心電極150aと外部電極150bが、純水で浸漬されている長さをＬｘとすると、
Ｌｘは、下記式（１）により求めることができる。
【００９４】
【式１】
Ｌｘ＝Ｌｒ（Ｒｒ／Ｒｍ）（１）
【００９５】
上記式（１）によりＬｘが求まると、純水水面152の位置が分かる。
純水比抵抗は、イオン交換樹脂筒を出たところでは、１８ＭΩ／ｃｍ^２程度であるが、時間の経過にしたがって、純水容器壁等を溶解してイオン濃度が増えると共に減少するが、純水比抵抗が経時変化しても、その都度、Ｒｒを計測して補正するので、常に正確な水面位置を検知できる。
【００９６】
酸素及び水素等のガスは、電気的に絶縁性であるので、リード線164aとアース間の電気抵抗は、中心電極150aと外部電極150bが浸漬している純水の電気抵抗だけで定まり、酸素又は水素の電気抵抗による影響は無視できる。
【００９７】
また、中心電極150aや外部電極150bをはじめ、全て、耐圧性に優れた構造としているので、材料的にも耐圧性の高い材料が使用可能で、従来のフロート式水面計のような圧力制限を受けることはない。
【００９８】
さらに、水面計５０において、高圧の酸素と水が共存する雰囲気で、電極間に電気を印可するのは、電解腐食を発生させるおそれがあるが、計測をパルス的に行ったり、中心電極150a，151a及び外部電極150b，151b等を、電解腐食に強いチタンや白金等の貴金属メッキを施す等により、それらの問題は回避することができ、さらに、リード線164aとアース間の電気抵抗Ｒｒの計測は、純水比抵抗の計測であるため、純水水質の評価データとしても利用でき、純水酸素高圧容器６２内の純水を交換する頻度も求めることができる。
【００９９】
図５は、この発明にかかる高圧水素製造装置の他の実施例で、上記実施例と同様に、水電解セル１は、水素高圧容器２内に発生した水素雰囲気中に収まるように配設され、電解される原料純水と、戻り純水及び発生した酸素を貯留する酸素高圧容器６２をも同様に具備しているが、差圧検知器５３の代わりに、圧力調整器７０を具備したもので、開放弁８及び１７は除かれている。
【０１００】
この圧力調整器７０は、酸素高圧容器６２と水素高圧容器２との間の純水の圧力差により、両者間の純水を、圧力の高い方から低い方に移動させ、差圧を解消させる機能を有するものである。
【０１０１】
すなわち、酸素高圧容器６２内の圧力が水素高圧容器２内の圧力より高くなると、酸素高圧容器６２内の純水が、圧力調整器７０に流入すると共に、同じ量の純水が圧力調整器７０から水素高圧容器２内に押し戻されるので、酸素高圧容器６２内の圧力は純水量が減少し、酸素貯留部５２の容積が増えるので、圧力は下がり、一方の水素高圧容器２内は純水量が増えるので圧力が上がって、差圧が解消される。
【０１０２】
また、圧力調整器７０は、純水の移動量を検知し、弁４４とニードル弁４３の開閉を制御装置（図示せず）で制御して、水素高圧容器２側に移動した純水を、酸素高圧容器６２に戻すと共に、このような移動が起こらないように、酸素放出口４５から放出する酸素量を調整して、圧力を均等にする機能も有するものである。
【０１０３】
水電解セル１から発生する水素の発生量を、圧力計５４で測定する圧力が、所定の圧力になるよう電源６１から水電解セル１に供給する電流量を制御して行うこと、酸素高圧容器６２への純水補給及び排水と、水素高圧容器２からの排水については、図１に示された実施例の方法と同じであるので、説明は省略する。
【０１０４】
図６（ａ）は、上記の実施例で用いられる具体的な圧力調整器７０の部分断面図で、図６（ｂ）は図６（ａ）におけるＡ−Ａ’に沿った断面図で、この圧力調整器７０は、非磁性材料で作られた中空円筒170と、中空円筒170の内面に密着して滑動する、磁性材料からなる内部滑動子171と、中空円筒170の外面に密着して滑動する、磁性材料で作られた外部滑動子172からなる装置主体190と、外部滑動子172の位置を検出する位置検出器200から構成されるもので、前記の内部滑動子171で二分された中空円筒170の一方には、水素高圧容器２内の純水184が導入され、他方には酸素高圧容器６２内の純水185が導入されるものである。
【０１０５】
水素高圧容器２からの純水184と、酸素高圧容器６２からの純水185は、内部滑動子171によって隔離され、分離されているため、純水184と純水185とが入り交じることは無く、水素高圧容器２内の圧力と、酸素高圧容器６２内の圧力が等しく、それらの間に差圧が発生しない状態では、内部滑動子171は、中空円筒170の中央に位置するように設定してある。
【０１０６】
したがって、水素高圧容器２内の圧力が、酸素高圧容器６２内の圧力より高くなったとすると、配管175から水素高圧容器２内の純水が、中空円筒170に流入して水素高圧容器２内の圧力を下げると共に、内部滑動子171が押されて、中空円筒170に純水が流入して純水184の容積が増え、押されて容積が減った純水185は配管176を通って、純水酸素高圧容器６２に流入して、酸素高圧容器６２内の酸素の容積を小さくするので酸素の圧力が増し、発生した差圧は自動的に解消される。
【０１０７】
この時、内部滑動子171は、中心からスプリング183側にズレた位置に移動し、内部滑動子171と外部滑動子172は磁力で結合しているので、外部滑動子172も同じ位置に移動し、外部滑動子172に固定棒181で固定されている遮光板177も同じように移動して開口部180の一部を覆い、開口部180を透過する光量が減少する。
【０１０８】
したがって、開口部180と開口部179とを透過する光量を比較することで、内部滑動子171がどちらに、どれだけ移動したかが分かるので、この開口部180と開口部179の透過光量比較により、内部滑動子171を元の中央位置に戻すようにニードル弁４３の開度を制御装置（図示せず）で制御する。
【０１０９】
なお、圧力調整器７０の光量比較のための位置検出器200は、差圧検知器５３の検出器120と同様の構成と機能を有するものである。
【０１１０】
このようにして、内部滑動子171が、常に、中央位置にあるようにニードル弁４３の開度を制御して、酸素放出口４５から放出する酸素量又は水素供給口５５から供給する水素量を調整することで、水電解セル１に差圧をかけること無く、高圧の水素が発生できる。
【０１１１】
以上のように制御しても、水素高圧容器２内の圧力が酸素高圧容器６２内の圧力よりも高い状態が続き、内部滑動子171の移動が止められない場合は、内部滑動子171がスプリング183に当たり、スプリング171を押さないと、それ以上内部滑動子171が動けなくなるので、内部滑動子171がこの位置まで動く間は、内部滑動子171の動きに対する制限が無いので、差圧は殆ど発生しない。
【０１１２】
しかしながら、内部滑動子171がスプリング183に当たると、内部滑動子171がスプリング183を押さない限り、それ以上動けなくなる。すなわち、内部滑動子171の移動による差圧調整はできないが、バイパス流路174を設けることにより、それ以上に、差圧が大きくなると、スプリング183が縮んで、水素高圧容器２内の純水がバイパス流路174を経由して、直接、酸素高圧容器６２内に流入し、差圧が一定以上には大きくすることはない。
【０１１３】
水素高圧容器２内の純水がバイパス流路174を経由して、直接、酸素高圧容器６２内に流入するようなことは、何らかの異常が発生し、制御装置（図示せず）によるニードル弁４３の開度制御だけでは、制御できなくなった異常事態を示すので、かかる異常事態の際には、緊急停止して、水電解セル１の電源６１を遮断すると共に、弁５８を除いて全て閉にし、水電解セル１からの水素及び酸素の発生を停止させ、水素高圧容器２の圧力を急速に低下させるよう、緊急遮断スイッチ（図示せず）や緊急放出弁４７、５８が設けてある。
【０１１４】
また、図５には示されていないが、装置を安全に停止するためには、酸素高圧容器６２及び水素高圧容器２内を、窒素ガスによる置換が行われるよう窒素配管が設けられている。
【０１１５】
また、内部滑動子171がスプリング183を押して、バイパス流路173又は174に純水が流入する差圧を、水電解セル１の許容耐圧以内になるようにスプリング182及び183の強さを設定することも、このような緊急停止においても、水電解セル１が耐圧以上の圧力を受けて破損することを防止する一つの手段である。
【０１１６】
また、中空円筒170の容積を、内部滑動子171の体積を除いて酸素高圧容器６２内の酸素貯留部５２の容積に等しくすると、緊急遮断が作動するまでに、±５０％の差圧の解消ができる。
【０１１７】
図７及び図８は、他の圧力調整器７０の部分断面図で、これらの図で示される圧力調整器７０は、先の圧力調整器７０のバイパス流路173又は174の代わりに、圧力調整器７０と並行し、中間に遮断弁220を有する純水配管213と、その開閉を操作するスイッチ211，212が設けられているものである。
【０１１８】
これらの圧力調整器７０においては、差圧が内部滑動子171の移動による調整可能以上に大きくなり、内部滑動子171がスプリング183を縮ませた場合、内部滑動子171が、末端に設けてあるスイッチ211，212により、遮断弁220を開放させ、例えば水素高圧容器２内の純水を純水配管213経由させて、直接、酸素高圧容器６２内に流入させ、差圧が一定以上には大きくすることはないよう機能するものである。
【０１１９】
【発明の効果】
この発明の高圧水素製造方法ならびに装置においては、水素高圧容器と酸素高圧容器内のどちらにも存在する純水を用いて、水素と酸素の差圧が所定の値（水電解セルの耐圧許容圧）を超えないように容器内の圧力を調整するため、圧力制御を容易にするとともに、コンプレッサーを用いること無く、水の電気分解だけで、水素のエネルギー利用に必要な３５０気圧以上の高圧水素の製造を極めて容易にしたものである。
【０１２０】
しかも、圧力調整に使用される純水は、水素高圧容器内に、酸素が発生する陽極側に供給した純水の一部が、水素を発生する陰極側に浸透してくるものであるため、特別に純水を供給しなくても自然に純水が供給されるもので、従来、不要なものとして、処理されていたものを有効に利用するもので、そのために特に格別な装置、操作を必要とするものではなく、しかも、少しの純水放出で効率よく差圧制御ができる効果的な差圧制御手段である。
【０１２１】
さらに、発生する水素及び酸素の圧力が高いほど、少ない純水量で差圧を下げることができるので、水素のエネルギー利用で必要な高圧の水素製造に応用して最適な効果が期待できる。
【０１２２】
また、この発明においては、水素高圧容器内の純水量を、酸素高圧容器内の酸素が貯留されている部分の容積より多くし、また、酸素高圧容器内の純水量を水素高圧容器内の水素が貯留される部分の容積より多くすることで、水素と酸素が混合し、爆鳴気が発生することも確実に防止できるのである。
【０１２３】
さらに、酸素の貯留量を水素の貯留量の４％以下にして、例え混合しても、爆発下限以下にすることも可能で、酸素高圧容器に大量の純水と少量の酸素を、水素高圧容器に少量の純水と大量の水素を、各々貯留することによって、また、水素高圧容器内の純水量を、酸素高圧容器内の酸素が貯留されている部分の容積より多くし、また、酸素高圧容器内の純水量を、水素高圧容器内の水素が貯留される部分の容積より多くすることにより、装置の故障や何らかの不都合の発生によって、酸素高圧容器側の酸素が漏洩して圧力が低下し、水素高圧容器内の純水が酸素高圧容器に流れ込む事故が発生しても、酸素高圧容器内の酸素が、全部漏洩して純水で置換されてからでないと、水素高圧容器内の水素が純水酸素容器内に流入することは起こず、逆に、水素が漏洩して水素高圧容器内の圧力が低下し、酸素高圧容器内の純水が流入しても、水素高圧容器内の水素が全て酸素高圧容器内の純水で置換された後でないと、酸素高圧容器内の酸素が水素高圧容器内に流入することはないので、爆鳴気が生成される事故が回避できる。
【０１２４】
また、この発明においては、従来のフロート式水面計に代えて、酸素等の気体と純水との電気伝導率特性が大きく異なっていることを利用し、水面を検知する水面計を使用することにより、高圧酸素と純水の密度差が小さくなっても、水面を安定に高精度に検知できるようにすると共に、フロートが高圧力の水素や酸素で押し潰されることによる発生圧力の限界を無くした。
【０１２５】
以上説明したように、この発明によって、水電解で発生する水素と酸素の圧力差を自動的に水電解セルの耐圧以内に制御できることが実現でき、これまで強く求められていた水素のエネルギー利用で必要とされる高圧の水素を、機械的なコンプレッサーを用いないで、安全に、安定して、しかも安価に製造でき、その実用上及び経済的効果は計り知れない程大きい。
【図面の簡単な説明】
【図１】この発明の一実施例である高圧水素製造装置の配置図である。
【図２】この発明で用いられる差圧検知器の構造を示す部分断面図である。
【図３】この発明で用いられる開放弁の構造を示す断面図（ａ）と側面図（ｂ）である。
【図４】この発明で用いられる水面計の構造を示す断面図である。
【図５】この発明の他の実施例である高圧水素製造装置の配置図である。
【図６】この発明で用いられる圧力調整器の部分断面図（ａ）とそのＡ−Ａ’断面図（ｂ）である。
【図７】この発明で用いられる他の圧力調整器圧力調整器部分断面図である。
【図８】この発明で用いられる他の圧力調整器圧力調整器部分断面図である。
【符号の説明】
１水電解セル
２水素高圧容器
５，６熱交換器
８，１７開放弁
１６ａ、１６ｂ純水配管
２８，３３イオン交換樹脂筒
３５比抵抗計
４０純水補給槽
４１高圧純水供給槽
５０水面計
５３差圧検知器
６２酸素高圧容器
７０圧力調整器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-pressure hydrogen production apparatus that generates high-pressure hydrogen, that is, compressed hydrogen gas, only by electrolysis of pure water using a solid polymer electrolyte membrane (PEM) without using a gas compressor. Belongs to hydrogen clean energy related technology.
[0002]
[Prior art]
Currently, fossil fuels such as coal and oil, which are the mainstream energy sources, are thought to cause global warming due to carbon dioxide emitted from their use, and in addition, nitrogen oxides emitted from the combustion of fossil fuels And sulfur oxides cause damage to human health and cause acid rain, and the reserves are not infinite, and there are many problems such as the possibility of depletion sooner or later.
[0003]
In order to solve these problems, there is a need for technological development to replace fossil fuels with renewable and clean natural energy. Among them, solar energy is equivalent to more than a year's energy consumed by human beings today, and solar energy alone can cover human energy demand. It's not a dream.
[0004]
Natural energy is generally extracted and used as electric power, as is well known as solar power generation and wind power generation, etc., but the electric power is stored as it is. However, the battery is very heavy and self-discharges, so there is a problem that it is consumed even if it is not used. Have.
[0005]
Therefore, a shift to a hydrogen economy society in which electric power obtained from natural energy is efficiently converted into clean hydrogen energy by water electrolysis and hydrogen is used as energy is being studied. In addition, the development of fuel cells using hydrogen as fuel (PEFC) has been actively promoted, and it is being studied for widespread use in private power generation for automobiles and homes. Therefore, it is required to produce hydrogen efficiently with natural energy.
[0006]
In response to such a request, PEM water electrolysis that directly electrolyzes pure water into hydrogen and oxygen by a solid polymer electrolyte membrane (hereinafter referred to as PEM) having proton (hydrogen ion) conductivity is efficiently performed. It attracts attention as a method for producing hydrogen.
This PEM water electrolysis has the feature that it can be freely started and stopped unlike alkaline water electrolysis, which lacks the ability to follow fluctuations and cannot be started and stopped freely. This is the most suitable method for converting the fluctuating electric power obtained into hydrogen.
[0007]
The biggest challenge when using the hydrogen thus obtained as energy is how to safely transport and store hydrogen, which is a gas, in a compact and portable manner. However, recently, the safety of high-pressure hydrogen has been reviewed, and compression by compressing hydrogen to a high pressure of 350 atm or higher has been studied. As hydrogen, a method of filling and storing and transporting in a cylinder or the like is increasing, and it has been widely used as a technology constituting a hydrogen economic society.
[0008]
Water electrolysis is capable of generating high-pressure hydrogen and oxygen by itself, and in principle, without using a pressure boosting device such as a compressor, the electrolysis alone can exceed 1000 atm. The generation of high-pressure hydrogen is not a dream, and there are no moving parts compared to mechanical boosting, so there is no need for maintenance work such as periodic inspections and replacement of consumable parts. Since it is good, it has many advantages such as low power costs.
[0009]
However, in electrolysis using a water electrolysis cell using PEM, since the current water electrolysis cell has a low withstand voltage, the generation of hydrogen and oxygen of several to several tens of atmospheres is at most 350, which is required for energy utilization. It is not possible to generate high-pressure hydrogen at atmospheric pressure or higher, and such a high-pressure booster is a development theme itself today, and it can generate high-pressure hydrogen only by electrolysis. The advent of high-pressure hydrogen production equipment that can be generated has been awaited.
[0010]
Patent No. 3,220,607 (US Pat. No. 5,690,797), which first solved this problem, placed a water electrolysis cell in pure water in a high-pressure vessel storing pure water and oxygen. Paying attention to the fact that when water electrolysis, the pressure acting on the water electrolysis cell is only the pressure difference between the generated hydrogen and oxygen, the water electrolysis cell with low pressure resistance is controlled by controlling the pressure of hydrogen and oxygen to be equal. Can be used to generate high-pressure hydrogen and oxygen far exceeding the pressure resistance of the water electrolysis cell.
[0011]
However, in the present invention, since the water electrolysis cell is immersed in pure water, if the water quality of the pure water is lowered and the specific resistance is lowered, there is a problem of leakage between the electrodes of the water electrolysis cell or electrolytic corrosion. Therefore, it cannot be said that it is easy to generate high-pressure hydrogen of several hundred atmospheres or more required for energy utilization.
[0012]
In particular, the resistivity of pure water decreases with increasing temperature, but in addition to that, elution of the container wall and the like with respect to pure water is accelerated, so it is always necessary to regenerate pure water with an ion exchange resin. If the pure water to be treated has a high pressure, the ion-exchange resin particles are destroyed, so that the pressure to be generated is limited, and it is difficult to generate high-pressure hydrogen required for the use of hydrogen energy.
[0013]
In order to prevent such problems, there has been a proposal (Japanese Patent Laid-Open No. 2001-130901) that the water electrolysis cell is housed in a high-pressure vessel filled with an insulating liquid. It was not found at present, and it was found to be poor in practicality.
[0014]
For example, PCB as an insulating liquid is flame retardant and excellent in performance, but its production and use are prohibited due to problems such as pollution. Currently, all insulating oils that can be used are flammable, oxygen As a result, pure water is excellent as an insulating liquid. However, as mentioned above, pure water has problems such as changes in specific resistance over time. Have difficulty.
[0015]
In order to solve these problems, the inventor previously disclosed a water electrolysis cell in Japanese Patent Application No. 2002-019713 in a high-pressure vessel that also serves as a reservoir for generated hydrogen. The pressure difference between the pressure of the high-pressure vessel in which the water electrolysis cell is arranged and the pressure of the high-pressure vessel that also serves as a reservoir for the generated oxygen is reduced to a pressure equal to or lower than that of the water electrolysis cell. Proposed to adjust.
[0016]
This proposal not only solved the problems of electrolytic corrosion and reduced pure water specific resistance, which were problems in the previous Patent No. 3,220,607, but also purified water even if the water electrolysis cell was damaged. It also has the function of sequestering oxygen and hydrogen, and it has made great progress in safety, such as preventing the generation of squeal.
[0017]
[Problems to be solved by the invention]
However, in this proposal, in order to keep the force acting on the water electrolysis cell within the pressure resistance of the water electrolysis cell, the differential pressure between the generated hydrogen and oxygen is controlled within the pressure resistance of the water electrolysis cell. Since the pressure resistance of the cell is constant, the higher the generated hydrogen and oxygen pressures, the higher the control accuracy required. Pressure control will eventually become the limiting factor for the hydrogen pressure generated by this proposal. It will be.
[0018]
That is, when the allowable pressure resistance of the water electrolysis cell is 4 atm and the generation pressure of hydrogen and oxygen is 10 atm, the pressure control accuracy may be 4/10, in other words, within 40%. Although it is possible to cope with this method without damaging the water electrolysis cell, considering that the hydrogen electrolysis cell generates 400 atmospheres of hydrogen and oxygen, it is 4/400, that is, a precision of 1% or more. High-precision pressure control is required, and it is difficult to achieve with normal pressure control methods. In addition, since the required pressure will become higher in the future, more severe pressure control accuracy is required. The method is almost impossible, and a new method is required.
[0019]
Furthermore, with the method in this proposal, a problem also arises in the water level gauge that measures the liquid level of pure water.
That is, pure water as a raw material for electrolysis is stored in a high-pressure vessel together with oxygen generated by water electrolysis, but the density of oxygen in a standard state (temperature 0 ° C .; 1 atm) is 1.429 × 10 6. ^-3 It is very light at g / cc. In the container, common sense that water goes down and oxygen goes up is valid, but assuming that oxygen is an ideal gas, 1 / 1.429 × 10 ^-3 = 700, 700 atm oxygen has the same density as water.
This means that at 700 atmospheres or higher, water floats on oxygen, and the usual rule of thumb that gas is lighter than water does not work.
[0020]
Fortunately, such density reversal does not occur unless the pressure is 1000 atm or higher in consideration of the size of oxygen molecules and intermolecular force. However, in the float-type water level meter that has been widely used in the past, water and oxygen If the density difference between the two becomes smaller, the operation becomes unstable due to water flow or the like, and the water surface cannot be detected accurately.
In addition to this, the float used in the float-type water level gauge has to be manufactured lightly with an apparent specific gravity of 1 or less, so there is a problem with pressure resistance, and pressure that is necessary for the use of hydrogen energy. It is considered difficult to produce a float that can withstand high temperatures, so this problem can be solved, and the development of a water level meter that operates stably under high pressure can be carried out in a wide and stable manner. Is strongly sought after.
[0021]
Unless the above problems, particularly the problem of pressure control accuracy, are solved, it is not possible to stably produce 350 atm or higher pressure hydrogen required for hydrogen energy utilization only by electrolysis of water. It can be said that the inventor solves the above problems, and does not use mechanical means such as a compressor, and the high-pressure hydrogen of 350 atm or higher required for use as energy. Has been studied for the purpose of providing a high-pressure hydrogen production apparatus that can be generated stably and safely only by electrolysis of water.
[0022]
As a result, the inventor noticed that pure water exists in both the hydrogen high-pressure vessel and the oxygen high-pressure vessel that store the generated hydrogen and oxygen, and the pure water is reduced from the higher pressure to the lower one. The pressure control problem can be solved by removing the differential pressure by moving to the surface, and the water level is detected by utilizing the fact that the electrical conductivity characteristics of oxygen and other gases are significantly different from those of pure water. As a result, it was found that the problem of the water level gauge could be solved, and the present invention was completed.
[0023]
[Means for Solving the Problems]
That is, the high-pressure hydrogen production method according to claim 1 of the present invention includes:
When electrolyzing pure water to generate hydrogen by a water electrolysis cell comprising a solid polymer electrolyte membrane,
The pressure difference between the hydrogen high-pressure vessel that stores the generated hydrogen and the oxygen high-pressure vessel that stores oxygen, Using pipes that communicate pure water existing in these containers, Adjusting the pure water present in each container by moving it to either side
It is characterized by.
[0024]
Moreover, the high pressure hydrogen production method according to claim 2 of the present invention comprises
When electrolyzing pure water to generate hydrogen by a water electrolysis cell comprising a solid polymer electrolyte membrane,
The pressure difference between the hydrogen high-pressure vessel for storing the generated hydrogen and the oxygen high-pressure vessel for storing oxygen is determined by adjusting the hydrogen pressure and oxygen pressure of each vessel, and Using piping for communicating pure water existing in those containers, Control by moving pure water present in each container to either side
It is characterized by.
[0025]
The invention according to claim 3 of the present invention is
In the high pressure hydrogen production method according to claim 1 or 2,
The pressure difference is
Keep it below the pressure resistance of the water electrolysis cell
It is characterized by.
[0026]
The invention according to claim 4 of the present invention is
In the high pressure hydrogen production method according to claim 1 or 2,
The movement of the pure water is
Connected to the pure water piping that connects the hydrogen high-pressure vessel and the oxygen high-pressure vessel, and is performed by operating an open valve provided in each vessel.
It is characterized by.
[0027]
The invention according to claim 5 of the present invention is
In the high pressure hydrogen production method according to claim 4,
The operation of the release valve is as follows:
Perform with the release valve immersed in pure water in the container.
It is characterized by.
[0028]
The invention according to claim 6 of the present invention provides
In the high pressure hydrogen production method according to claim 1 or 2,
The movement of the pure water is
This is done automatically by the pressure regulator installed in the pure water pipe connecting the hydrogen high-pressure vessel and the oxygen high-pressure vessel.
It is characterized by.
[0029]
The invention according to claim 7 of the present invention provides
In the high pressure hydrogen production method according to claim 1 or 2,
The movement of the pure water is
It is performed by opening and closing the valve provided in the pure water pipe connecting the hydrogen high pressure vessel and the oxygen high pressure vessel.
It is characterized by.
[0030]
The invention according to claim 8 of the present invention provides
In the high pressure hydrogen production method according to claim 1 or 2,
The pure water volume stored in the hydrogen high-pressure vessel is larger than the oxygen volume stored in the oxygen high-pressure vessel, and the pure water volume stored in the oxygen high-pressure vessel is larger than the hydrogen volume stored in the hydrogen high-pressure vessel. What to do while controlling
Is a high-pressure hydrogen production method characterized by
[0031]
The invention according to claim 9 of the present invention provides
In the high pressure hydrogen production method according to claim 1 or 2,
Controlling the amount of oxygen stored in the oxygen high-pressure vessel within 4% of the amount of hydrogen stored in the hydrogen high-pressure vessel
Is a high-pressure hydrogen production method characterized by
[0032]
Furthermore, the invention according to claim 10 of the present invention is
A water electrolysis cell comprising a solid polymer electrolyte membrane, a hydrogen high-pressure vessel for storing generated hydrogen and pure water accompanying hydrogen, an oxygen high-pressure vessel for storing raw material and return pure water and generated oxygen, and a pure hydrogen in the hydrogen high-pressure vessel Communication between water and pure water in the oxygen high-pressure vessel For differential pressure adjustment Provide pure water piping and a differential pressure detector to detect the pressure difference between hydrogen and oxygen in the hydrogen high-pressure vessel and oxygen high-pressure vessel and to control the pressure difference.
Is a high-pressure hydrogen production apparatus characterized by
[0033]
The invention according to claim 11 of the present invention provides
A water electrolysis cell comprising a solid polymer electrolyte membrane, a hydrogen high-pressure vessel for storing generated hydrogen and pure water accompanying hydrogen, an oxygen high-pressure vessel for storing raw pure water and generated oxygen, and pure water in a hydrogen high-pressure vessel Communicates with pure water in the oxygen high-pressure vessel For differential pressure adjustment Provided with a pressure regulator that is provided in the pure water piping and the pure water piping and has a slider that slides in accordance with the pressure difference between the pure water of the hydrogen high-pressure vessel and the pure water of the oxygen high-pressure vessel.
Is a high-pressure hydrogen production apparatus characterized by
[0034]
The invention according to claim 12 of the present invention provides
The high-pressure hydrogen production apparatus according to claim 10 or 11,
The water electrolysis cell is
Installed in a hydrogen high-pressure vessel or pure water oxygen high-pressure vessel
It is characterized by.
[0035]
The invention according to claim 13 of the present invention provides
The high-pressure hydrogen production apparatus according to claim 10 or 11,
A high-pressure pure water supply tank and a pure water replenishing tank above the oxygen high-pressure vessel, a water feed pump connecting the bottoms thereof, an ion exchange resin cylinder, a pure water circulation feed pipe having a filter, and a high-pressure pure water supply tank The pure water circulation return pipe connecting the upper part of the pure water supply tank and the upper part of the pure water supply tank, the oxygen supply pipe connecting the upper part of the oxygen high pressure container and the upper part of the high pressure pure water supply tank, and the pure water connecting the bottom of the high pressure pure water supply tank and the inside of the oxygen high pressure container Also have a pure water production / supply system where water injection pipes are installed
Is a high-pressure hydrogen production apparatus characterized by
[0036]
The invention according to claim 14 of the present invention provides
The high-pressure hydrogen production apparatus according to claim 10,
Pure water piping for communicating pure water in the hydrogen high-pressure vessel and pure water in the oxygen high-pressure vessel,
It consists of two pipes: a pipe with an open valve in the hydrogen high-pressure vessel and a pipe with an open valve in the oxygen high-pressure vessel.
It is characterized by.
[0037]
The invention according to claim 15 of the present invention provides
The high-pressure hydrogen production apparatus according to claim 14,
The release valve is
Front view has a triangular outlet
It is characterized by.
[0038]
The invention according to claim 16 of the present invention provides
The high-pressure hydrogen production apparatus according to claim 10,
The differential pressure detector is
Both ends are sealed with bellows that expands and contracts in the axial direction under the pressure of a hydrogen high-pressure vessel or oxygen high-pressure vessel, and a cylinder made of a nonmagnetic material filled with an inert fluid inside, and in close contact with the inner surface of the cylinder. Detection of differential pressure based on the position of the external magnetic body changed due to the expansion and contraction of the bellows, and the apparatus main body consisting of an internal magnetic body provided on the outer surface, and an external magnetic body provided in close contact with the outer surface. Consists of containers
It is characterized by.
[0039]
The invention according to claim 17 of the present invention provides
The high-pressure hydrogen production apparatus according to claim 16,
The differential pressure detector is
It is composed of a light-shielding plate that moves in conjunction with an external magnetic material, a display plate that has an opening shielded by the light-shielding plate, and a photoelectric meter that converts the amount of light transmitted through the opening into an electrical signal.
It is characterized by.
[0040]
The invention according to claim 18 of the present invention provides
The high-pressure hydrogen production apparatus according to claim 16,
The differential pressure detector is
Having a slider as a component that slides on the electric resistor in conjunction with the external magnetic material
It is characterized by.
[0041]
The invention according to claim 19 of the present invention provides
The high-pressure hydrogen production apparatus according to claim 11,
The pressure regulator is
A hollow cylinder made of a non-magnetic material with one end communicating with pure water in the hydrogen high-pressure vessel and the other end communicating with pure water in the oxygen high-pressure vessel, blocking both pure water and closely contacting the inner surface of the hollow cylinder Position detection for detecting the position of the external slider and an apparatus main body comprising an inner slider made of a magnetic material that slides and an outer slider made of a magnetic material that slides in close contact with the outer surface of the hollow cylinder Consists of containers
It is characterized by.
[0042]
The invention according to claim 20 of the present invention provides
The high pressure hydrogen production apparatus according to claim 19,
The hollow cylinder is
Both ends have springs, and the internal slider has flow paths at both ends that allow pure water to flow when it slides to the ends.
It is characterized by.
[0043]
The invention according to claim 21 of the present invention provides
The high pressure hydrogen production apparatus according to claim 19,
The hollow cylinder is
Both ends have springs, and both ends have a switch that opens and closes a shut-off valve provided in a pipe for circulating pure water that operates when the internal slider slides to the end.
It is characterized by this.
[0044]
The invention according to claim 22 of the present invention provides
The high pressure hydrogen production apparatus according to claim 19,
The hollow cylinder is
The volume of hydrogen stored in the hydrogen high-pressure vessel and the volume of oxygen stored in the oxygen high-pressure vessel should be equal to the smaller volume, or a substantial volume less than that.
It is characterized by.
[0045]
The invention according to claim 23 of the present invention provides
The high pressure hydrogen production apparatus according to any one of claims 10 to 22,
Have a water level meter that has a central electrode and a cylindrical electrode with the central electrode at the center
Is a high-pressure hydrogen production apparatus characterized by
[0046]
The invention according to claim 24 of the present invention provides
The high pressure hydrogen production apparatus according to claim 23,
The water level gauge is
A main electrode having concentric outer electrodes arranged outside the rod-shaped center electrode, and a sub-electrode having concentric outer electrodes arranged outside the rod-shaped center electrode covered with an electrically insulating cylinder except for the tip
It is characterized by.
[0047]
Furthermore, the invention according to claim 25 of the present invention provides
The high pressure hydrogen production apparatus according to any one of claims 10 to 23,
The hydrogen high-pressure vessel is equipped with a normally open hydrogen emergency release valve, the pure water oxygen high-pressure vessel is always equipped with a normally open oxygen emergency release valve, and the water electrolysis cell is equipped with an emergency power cut-off switch.
Is a high-pressure hydrogen production apparatus characterized by
[0048]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the high-pressure hydrogen production method and apparatus of the present invention will be described below with reference to the accompanying drawings.
[0049]
FIG. 1 is a schematic explanatory view showing an embodiment of the high-pressure hydrogen production apparatus of the present invention. This high-pressure hydrogen production apparatus is basically arranged so as to be contained in the hydrogen atmosphere generated by the water electrolysis cell 1. The hydrogen high-pressure vessel 2 disposed, the raw pure water to be electrolyzed, the oxygen high-pressure vessel 62 for storing the return pure water and the generated oxygen, the pure water in the hydrogen high-pressure vessel 2, and the pure water in the oxygen high-pressure vessel 62 It consists of pure water pipes 16a and 16b for communicating water, a hydrogen high pressure vessel 2 and a differential pressure detector 53 for sensing the pressure difference between hydrogen and oxygen in the oxygen high pressure vessel 62 and controlling the pressure difference. Is.
[0050]
In the high-pressure hydrogen production apparatus shown in FIG. 1, pure water to be electrolyzed is sent from the oxygen high-pressure vessel 62 to the water electrolysis cell 1 by the pump 7, and when power necessary for water electrolysis is supplied from the power supply 61, After electrolysis, hydrogen and pure water are discharged from the hydrogen discharge port 3 into the hydrogen high-pressure vessel 2, and the generated oxygen and undecomposed pure water are sent to the oxygen high-pressure vessel 62 through the return pipe 4.
[0051]
The hydrogen high-pressure vessel 2 and the oxygen high-pressure vessel 62 are respectively pressurized by the generated hydrogen and oxygen to reach a predetermined pressure, for example, 400 atm. When there is no demand for hydrogen, electrolysis is performed in this state. In the case of stopping and waiting, when hydrogen is required, the valve 57 is opened and the needle valve 56 is gradually opened to supply hydrogen from the hydrogen supply port 55.
[0052]
When the pressure gauge 54 measures that the pressure in the hydrogen high-pressure vessel 2 decreases due to the supply of hydrogen, a water electrolysis cell is supplied from the power supply 61 by a command from a control device (not shown) linked to the pressure gauge 54. The power supply is resumed at 1, and the power is supplied until the pressure of the pressure gauge 54 returns to the original value again.
[0053]
When the pressure of the pressure gauge 54 is recovered, the opening degree of the needle valve 56 is further increased, and the power of the power supply 61 is increased until the pressure of the pressure gauge 54 is recovered. In this way, if the pressure does not decrease even when the opening degree of the needle valve 56 is increased, or the supply power of the power source 61 reaches the allowable maximum power, the state is maintained and the supply of hydrogen is continued.
[0054]
Oxygen generated in the water electrolysis cell 1 together with hydrogen in the electrolysis of pure water is stored in the oxygen reservoir 52 above the oxygen high-pressure vessel 62.
[0055]
A differential pressure between the pressure of oxygen stored in the oxygen storage section 52 and the pressure of hydrogen in the hydrogen high-pressure vessel 2 is a differential pressure detector 53 shown as an example of the following during electrolysis and hydrogen supply. Based on this measurement signal, the control device (not shown) normally controls the opening / closing of the valve 44 and the opening of the needle valve 43 so that the differential pressure signal from the differential pressure detector 53 becomes zero. The amount of oxygen released from the oxygen outlet 45 is controlled.
[0056]
In this way, electrolysis is performed and hydrogen is supplied from the hydrogen supply port 55 while the pressure in the hydrogen high-pressure vessel 2 and the pressure in the pure water oxygen high-pressure vessel 62 are controlled to be equal.
[0057]
In the conventional high-pressure hydrogen production apparatus, as described above, the differential pressure between the oxygen high-pressure vessel 62 and the hydrogen high-pressure vessel 2 is adjusted by the release of oxygen and hydrogen, particularly oxygen. Since the allowable pressure that can be expected from the withstand pressure is about 4 atm, as described above, for example, when hydrogen and oxygen at 400 atm are generated using this water electrolysis cell 1, high accuracy of 1% or more is required. Pressure control is required.
[0058]
For this reason, in the present invention, the differential pressure is caused by the water electrolysis cell due to the pressure control disturbance due to the fluctuation of the hydrogen consumption of the apparatus connected to the hydrogen supply port 55 and receiving the hydrogen supply, the fluctuation of the power supply of the power supply 61, etc. In order to avoid the occurrence of a pressure difference exceeding the allowable pressure resistance of the water electrolysis cell 1 due to pressure control disturbance, the pure water in the hydrogen high-pressure vessel 2 and the pure water in the oxygen high-pressure vessel 62 are communicated. There are provided deionized water pipes 16a and 16b and open valves 8 and 17 connected to the deionized water pipes 16a and 16b and operating based on the differential pressure.
[0059]
Therefore, when the hydrogen pressure in the hydrogen high-pressure vessel 2 becomes lower than the oxygen pressure in the oxygen high-pressure vessel 62 and the differential pressure may exceed the allowable pressure value of the cell 1, the release valve 8 The pure water in the oxygen high-pressure vessel 62 is released into the hydrogen high-pressure vessel 2, thereby reducing the pure water volume in the oxygen high-pressure vessel 62 and increasing the oxygen volume in the oxygen reservoir 52. As the oxygen pressure decreases, the pressure in the hydrogen high-pressure vessel 2 increases, and the differential pressure is maintained below the allowable pressure resistance.
[0060]
At that time, the hydrogen volume in the hydrogen high-pressure vessel 2 is 20 L, the oxygen volume in the oxygen high-pressure vessel 62 is 0.4 L (2% of hydrogen), and the generated pressure is 400 atm. Since 4 cc of pure water flows out from the oxygen high-pressure vessel 62 and flows into the hydrogen high-pressure vessel 2, the oxygen pressure decreases by 4 atm, which is 1% of 400 atm, and the hydrogen pressure increases by 0.08 atm. The differential pressure of 4.08 atm in total can be efficiently eliminated with the flow of pure water of only 4 cc.
[0061]
Control of the water surface 51 in the oxygen high-pressure vessel 62 is important particularly when hydrogen is generated at 350 atm or higher. In the present invention, a water level meter 50 as described later is disposed in the oxygen high-pressure vessel 62 and is always used. When the water surface 51 is measured and the water surface 51 is lowered from a predetermined position, the valve 38 is opened and pure water in the high-pressure pure water supply tank 41 is poured into the oxygen high-pressure vessel 62 by using its gravity. When pure water flows into the oxygen high-pressure vessel 62 from the supply tank 41, the same amount of oxygen flows into the high-pressure pure water supply tank 41 through the valve 39 at the same time.
[0062]
In order to flow the pure water in the high-pressure pure water supply tank 41 into the oxygen high-pressure vessel 62 using gravity, the high-pressure pure water supply tank 41 is placed at a position higher than the oxygen high-pressure vessel 62, and the high-pressure pure water supply tank It is important to install the pure water supply tank 40 for supplying pure water to 41 at the same position or at a higher position.
[0063]
Pure water supply to the high-pressure pure water supply tank 41 is performed by closing the valves 38 and 39 and opening the valves 36 and 37. That is, the valves 38 and 39 are closed and separated from the oxygen high-pressure vessel 62, the valves 36 and 37 are opened, and the pure water in the pure water replenishing tank 40 is passed through the ion exchange resin cylinder 33 and the filter 34 by the pump 32. .
[0064]
At that time, the specific resistance of pure water is measured by the specific resistance meter 35. If the specific resistance value is low, the catalyst electrode of the water electrolysis cell 1 is poisoned and the life of the water electrolysis cell 1 is shortened. It is circulated, and the ion exchange resin cylinder 33 is passed a plurality of times until the specific resistance value becomes higher than a predetermined value, and the ion exchange treatment is performed.
[0065]
If the pure water replenishing tank 40 is installed above the high pressure pure water supply tank 41, the inside of the high pressure pure water supply tank 41 is filled with pure water and air bubbles can be removed, so the valves 36 and 37 are closed. Thus, the pressure fluctuation when the valves 38 and 39 are opened is only a change in the volume of pure water and can be almost ignored in terms of pressure control.
[0066]
Since the circulation of pure water by the pump 32 is performed at normal pressure, the pump 32, the ion exchange resin cylinder 33, the filter 34, and the resistivity meter 35 all operate at normal pressure.
The end of the pure water circulation by the pump 32 is determined by the pure water specific resistance value measured by the specific resistance meter 35.
[0067]
In addition, by providing a spare tank having the same function as the high-pressure pure water supply tank 41, if either one is always kept in standby, the supply of pure water to the oxygen high-pressure vessel 62 will not be delayed.
[0068]
Since the pure water in the oxygen high-pressure vessel 62 is sent to the water electrolysis cell 1 and becomes a raw material for water electrolysis, it is stored for a long time and has a pure water specific resistance of, for example, 6 MΩ / cm. ² As described below, when the water quality deteriorates, the catalyst electrode of the water electrolysis cell 1 may be poisoned and the life of the water electrolysis cell 1 may be shortened. It is desirable to replace a part of pure water with fresh pure water as needed.
[0069]
To replace the pure water in the oxygen high-pressure vessel 62, the valve 18 is opened and the pure water in the pure water oxygen high-pressure vessel 62 is poured into the pure water discharge tank 19, the valve 18 is closed, the valve 21 is opened, and the pure water discharge tank is filled. The pure water in 19 is discharged to the water receiving tank 23, and the corresponding amount of pure water is supplied from the high-pressure pure water supply tank 41.
[0070]
At that time, in order to reduce the pressure fluctuation in the pure water exchange operation, the volume of the pure water discharge tank 19 is preferably about 1% of the oxygen reservoir 52, and the pure water exchange frequency is the use of pure water. Depending on the amount, there is no problem with about 10 times a day (about 10%).
[0071]
In the hydrogen high-pressure vessel 2, permeated pure water from the anode to the cathode of the water electrolysis cell 1 is discharged from the hydrogen discharge port 3 together with the generated hydrogen, and is collected at the bottom in the hydrogen high-pressure vessel 2.
[0072]
The amount of pure water stored should be at least about twice the volume of the oxygen reservoir 52 of the oxygen high-pressure vessel 62. The amount is controlled by detecting the water surface 9 with the water level gauge 10 so that the pure water exceeds a predetermined amount. When water increases, the valve 11 is opened and poured into the pure water receiving tank 12. The volume of the pure water receiving tank 12 is determined so that the pressure fluctuation caused by opening the valve 11 and pouring pure water into the pure water receiving tank 12 is equal to or less than the allowable pressure resistance determined by the pressure resistance of the water electrolysis cell 1.
[0073]
For example, when the maximum generation pressure of hydrogen in the hydrogen high-pressure vessel 2 is 400 atmospheres, the stored hydrogen volume is 20 liters, and the allowable pressure of the water electrolysis cell 1 is 4 atmospheres, the volume of the pure water receiving tank 12 is 0.2. If it is less than 1 liter (1%), the hydrogen pressure fluctuation in the operation of opening the valve 11 and flowing pure water into the pure water receiving tank 12 is 400 × 1% = 4 atm at the maximum.
[0074]
At this time, even if some factors overlap and a differential pressure of 4 atm or more is generated by this operation, the differential pressure exceeding the allowable value of the pressure resistance of the water electrolysis cell 1 by the action of the release valves 8 and 17 is Does not occur.
[0075]
In FIG. 1, 5 is a heat exchanger for cooling the heat generated by electrolysis of water, 6 is a heat exchanger for bringing pure water supplied to the water electrolysis cell 1 to a desired temperature, and 13 is Electric resistance type water level meter, 15 is a pure water discharge pipe, 20 is an electric type water level meter, 24 is a float type water level meter, 25 is a water supply port, 27 is a pump, 28 is an ion exchange cylinder, 29 is a filter, 30 is a pure water resistivity meter for measuring pure water resistivity, 31 is a float type water level meter, 46 is an oxygen emergency discharge port, 47 is an oxygen emergency discharge valve, 48 is a pressure gauge, and 49 is hydrogen in oxygen. A gas leak detector for detecting the concentration, 58 is a hydrogen emergency release valve, 59 is a hydrogen emergency discharge port, and 60 is a leak detector for measuring the oxygen concentration in hydrogen.
[0076]
FIG. 2 is a partial cross-sectional view showing an example of the differential pressure detector used in the present invention. As shown in the figure, the differential pressure detector 53 is the pressure of the hydrogen high-pressure vessel 2 or the oxygen high-pressure vessel 62. Both ends are sealed with bellows 106 and 107 that expand and contract in the axial direction, and the cylinder 101 made of a nonmagnetic material filled with an inert fluid is provided in close contact with the inner surface of the cylinder 101 so as to be slidable in the axial direction. An apparatus main body 100 comprising an internal magnetic body 104, an external magnetic body 105 that is in close contact with the outer surface of the cylinder 101 and is slidable in the axial direction in conjunction with the internal magnetic body 104, and the bellows 106, 107 It comprises a detector 120 that detects a differential pressure in conjunction with an external magnetic body 105 that slides by expansion and contraction.
[0077]
The detector 120 includes a light shielding plate 119 that moves in conjunction with the external magnetic body 105, a display plate 116 that has openings 117 and 118 that are shielded by the light shielding plate 119, and a transmission that passes through the openings 117 and 118. It comprises a photoelectric meter (not shown) that converts the amount of light into an electrical signal.
[0078]
In the differential pressure detector 53 shown in FIG. 2, hydrogen in the hydrogen high-pressure vessel 2 is sent to the hydrogen pressure chamber 110 through the hydrogen pipe 112, and oxygen in the oxygen high-pressure vessel 62 is sent from the oxygen pipe 113 to the oxygen pressure chamber 111. These pressures are transmitted to bellows 106 and 107, respectively.
[0079]
Since the bellows 106 and 107 and the cylinder 101 are filled with a fluid such as machine oil, the volume hardly changes even under pressure, and the bellows 106 and 107 are sent by the hydrogen pipe 112 and the oxygen pipe 113. Even if pressure is received from high-pressure hydrogen and oxygen, the pressure is not crushed.
[0080]
When the pressures of hydrogen and oxygen sent by the hydrogen pipe 112 and the oxygen pipe 113 are equal, the force with which the bellows 106 and 107 are pushed from the hydrogen pressure chamber 110 and the oxygen pressure chamber 111 is equal. Maintain a stopped state in the center of.
[0081]
However, when the pressure of hydrogen sent through the hydrogen pipe 112 is higher than the pressure of oxygen sent through the oxygen pipe 113, the spring 114 extends and the spring 115 contracts due to the differential pressure, and the differential pressure and the extension of the springs 114 and 115 increase. The inner magnetic body 105 is pushed by the fixing rods 102 and 103 and moved to the oxygen pressure chamber 111 side to a position where the force due to the shrinkage is balanced.
[0082]
Since the internal magnetic body 104 and the external magnetic body 105 are magnetically coupled to each other by exerting a magnetic force, the external magnetic body 105 moves along with the movement of the internal magnetic body 104 and is fixed to the external magnetic body 105. The light shielding plate 119 moves to cover a part of the opening 118 on the oxygen side and the amount of light transmitted through the opening 117 does not change, but the amount of light transmitted through the opening 118 decreases.
[0083]
Conversely, when the pressure of hydrogen sent through the hydrogen pipe 112 is lower than the pressure of oxygen sent from the oxygen pipe 113, a part of the hydrogen-side opening 117 is covered with the light shielding plate 119 and passes through the opening 117. The amount of light to be reduced decreases.
[0084]
Therefore, by measuring the amount of light transmitted through the openings 117 and 118, the magnitude of the differential pressure between the hydrogen pressure sent from the hydrogen pipe 112 and the oxygen pressure sent from the oxygen pipe 113 is higher and which is lower. As can be seen, for example, by controlling the opening and closing of the valve 44 and the needle valve 43 in FIG. 1 to control the amount of released oxygen, there is no difference in the amount of light transmitted through the openings 117 and 118, and the differential pressure Can be set to zero.
[0085]
In the above description, the method of measuring the position of the internal magnetic body 104 by light quantity measurement has been described, but the measurement can also be performed using a slide resistance. That is, the slider is fixed to the external magnetic body 105, and the slider moves on the slide resistance in accordance with the movement of the slider integrated with the external magnetic body 105. Can also be measured.
[0086]
FIG. 3 is a cross-sectional view (a) and a side view (b) showing the structure of the release valves 8 and 17 used in the present invention. As shown, the release valves 8 and 17 are cylindrical. The valve main body 130 is provided with a discharge port 132 for discharging pure water, and a cylinder 131 and a spring 133 interlocking with the cylinder 131 are provided therein so that the biasing force of the spring 133 can be adjusted. A pipe 135 and a pure water pipe 16a or 16b for moving pure water in the hydrogen high-pressure vessel 2 or the oxygen high-pressure vessel 62, and a vent 137.
[0087]
The release valves 8 and 17 are cylinders 131 that are pushed up by the pressure of pure water transmitted by the connecting pipe 138 by loosening the fixing nut 136 and rotating the screw head 134 to adjust the pressing strength of the spring 133. However, it is located above the discharge port 132, and the pressure at which the pure water in the connection pipe 138 is discharged from the discharge port 132 can be set to a desired pressure (allowable pressure determined by the pressure resistance of the cell). It is also possible to tighten the nut 136 so that the setting does not change.
[0088]
In the cylinder 131, when the pressure of the atmosphere in which the valve main body 130 is placed becomes higher than the pure water pressure in the connection pipe 138, the spring 133 contracts due to the differential pressure, and the cylinder 131 starts to move upward, and the connection pipe 138 When the pressure of pure water further increases, the cylinder 131 crosses the discharge port 132, and the pure water in the connection pipe 138 is discharged from the discharge port 132, so the pressure in the connection pipe 138 decreases. By making the shape of the discharge port 132 into an inverted triangular shape, the amount of pure water released is small when the differential pressure is small, and increases when the differential pressure is large, and the differential pressure can be quickly eliminated.
[0089]
FIG. 4 is a cross-sectional view of a water level meter utilizing the fact that the electrical conductivity characteristics of oxygen and other gases are significantly different from those of pure water, which is the water level meter 50 in FIG. 1 and includes a rod-shaped center electrode 150a, Outside the center electrode 150a, a main electrode 150 comprising an external electrode 150b arranged concentrically, a rod-shaped center electrode 151a covered with an electrically insulating cylinder except for the tip, and outside the center electrode 151a The sub-electrode 151 is composed of an external electrode 151b arranged concentrically.
[0090]
In the figure, 152 is a pure water surface, 153a and 153b are vent holes, 154a and 154b are mounting portions for the external electrodes 150b and 151b, 155a and 155b are mounting portions for the center electrodes 150a and 150b, and 156a and 156b are insulators. , 157a and 157b are fixing jigs for mounting the external electrodes 150b and 151b, 158 is a mounting flange, 159a and 159b are nuts for fixing the fixing jigs 157a and 157b, 160a and 160b are insulating plates, 161a And 161b are washers, 162a and 162b are lead wires, 163a and 163b are washers, 164a and 164b are nuts for fixing the center electrodes 150a and 150b, and 165a to 167b are O-rings.
[0091]
In the water level meter 50 having such a configuration, when the center electrode 150a and the external electrode 150b are immersed in pure water, the resistance of the pure water immersed between the center electrode 150a and the external electrode 150b is between the lead wire 162a and the ground. Since it can be measured by connecting an electric resistance meter, this resistance value is Rm.
[0092]
On the other hand, when the electrical resistance between the lead wire 162b and the ground is measured, the resistance of pure water between the external electrode 151b and the tip of the central electrode 150b exposed without being covered with the insulating cylinder 168 can be measured. The resistance value is Rr.
[0093]
When the length of the tip of the center electrode 151a not covered with the insulating cylinder 168 is Lr, and the length in which the center electrode 150a and the external electrode 150b are immersed in pure water is Lx,
Lx can be obtained by the following equation (1).
[0094]
[Formula 1]
Lx = Lr (Rr / Rm) (1)
[0095]
When Lx is obtained from the above equation (1), the position of the pure water surface 152 is known.
The pure water specific resistance is 18 MΩ / cm when leaving the ion exchange resin cylinder. ² However, as the time elapses, the pure water container wall is dissolved and the ion concentration increases and decreases, but even if the pure water resistivity changes with time, Rr is measured and corrected each time. Therefore, it is always possible to detect the accurate water surface position.
[0096]
Since gases such as oxygen and hydrogen are electrically insulative, the electrical resistance between the lead wire 164a and the ground is determined only by the electrical resistance of pure water in which the center electrode 150a and the external electrode 150b are immersed. Or the influence of the electrical resistance of hydrogen is negligible.
[0097]
In addition, since the center electrode 150a and the external electrode 150b all have a structure with excellent pressure resistance, materials with high pressure resistance can be used. I will not receive it.
[0098]
Furthermore, in the water level meter 50, applying electricity between the electrodes in an atmosphere in which high-pressure oxygen and water coexist may cause electrolytic corrosion, but the measurement may be performed in a pulsed manner or the center electrode 150a, These problems can be avoided by applying a precious metal plating such as titanium or platinum that is resistant to electrolytic corrosion to 151a and external electrodes 150b and 151b, etc. Furthermore, measurement of electrical resistance Rr between lead wire 164a and ground Since it is a measurement of pure water specific resistance, it can be used as evaluation data of pure water quality, and the frequency of exchanging pure water in the pure water oxygen high-pressure vessel 62 can also be obtained.
[0099]
FIG. 5 shows another embodiment of the high-pressure hydrogen production apparatus according to the present invention. Like the above-described embodiment, the water electrolysis cell 1 is disposed so as to be accommodated in the hydrogen atmosphere generated in the hydrogen high-pressure vessel 2. The raw material pure water to be electrolyzed and the oxygen high-pressure vessel 62 for storing the return pure water and the generated oxygen are similarly provided, but instead of the differential pressure detector 53, a pressure regulator 70 is provided. Thus, the release valves 8 and 17 are removed.
[0100]
The pressure regulator 70 moves the pure water between the oxygen high pressure vessel 62 and the hydrogen high pressure vessel 2 from the higher pressure to the lower pressure due to the pressure difference between the oxygen high pressure vessel 62 and the hydrogen high pressure vessel 2 to eliminate the differential pressure. It has a function.
[0101]
That is, when the pressure in the oxygen high-pressure vessel 62 becomes higher than the pressure in the hydrogen high-pressure vessel 2, pure water in the oxygen high-pressure vessel 62 flows into the pressure regulator 70 and the same amount of pure water is added to the pressure regulator 70. Is pushed back into the hydrogen high-pressure vessel 2, the pressure in the oxygen high-pressure vessel 62 decreases the amount of pure water, and the volume of the oxygen reservoir 52 increases, so the pressure decreases, and the amount of pure water in one hydrogen high-pressure vessel 2 is reduced. Since it increases, the pressure rises and the differential pressure is eliminated.
[0102]
Further, the pressure regulator 70 detects the amount of movement of pure water, controls the opening and closing of the valve 44 and the needle valve 43 with a control device (not shown), and moves the pure water moved to the hydrogen high-pressure vessel 2 side. In addition to returning to the oxygen high-pressure vessel 62, the amount of oxygen released from the oxygen release port 45 is adjusted so that such movement does not occur, and the pressure is equalized.
[0103]
The amount of hydrogen generated from the water electrolysis cell 1 is controlled by controlling the amount of current supplied from the power source 61 to the water electrolysis cell 1 so that the pressure measured by the pressure gauge 54 becomes a predetermined pressure; The pure water supply and drainage to 62 and the drainage from the hydrogen high-pressure vessel 2 are the same as the method of the embodiment shown in FIG.
[0104]
6A is a partial cross-sectional view of a specific pressure regulator 70 used in the above embodiment, and FIG. 6B is a cross-sectional view along AA ′ in FIG. This pressure regulator 70 is in close contact with a hollow cylinder 170 made of a nonmagnetic material, an internal slider 171 made of a magnetic material that slides in close contact with the inner surface of the hollow cylinder 170, and an outer surface of the hollow cylinder 170. It consists of a device main body 190 consisting of an external slider 172 made of a magnetic material that slides, and a position detector 200 that detects the position of the external slider 172, and is divided into two by the internal slider 171. Pure water 184 in the hydrogen high-pressure vessel 2 is introduced into one of the hollow cylinders 170, and pure water 185 in the oxygen high-pressure vessel 62 is introduced into the other.
[0105]
The pure water 184 from the hydrogen high-pressure vessel 2 and the pure water 185 from the oxygen high-pressure vessel 62 are separated and separated by the internal slider 171, so that the pure water 184 and the pure water 185 do not enter and leave each other. In the state in which the pressure in the hydrogen high-pressure vessel 2 and the pressure in the oxygen high-pressure vessel 62 are equal and no differential pressure is generated between them, the internal slider 171 is set to be positioned at the center of the hollow cylinder 170. It is.
[0106]
Therefore, if the pressure in the hydrogen high-pressure vessel 2 becomes higher than the pressure in the oxygen high-pressure vessel 62, pure water in the hydrogen high-pressure vessel 2 flows into the hollow cylinder 170 from the pipe 175 and enters the hydrogen high-pressure vessel 2. While reducing the pressure, the internal slider 171 is pushed, and pure water flows into the hollow cylinder 170 to increase the volume of the pure water 184. Since it flows into the water oxygen high pressure vessel 62 and the volume of oxygen in the oxygen high pressure vessel 62 is reduced, the pressure of oxygen increases and the generated differential pressure is automatically eliminated.
[0107]
At this time, the internal slider 171 moves to a position shifted from the center toward the spring 183, and the internal slider 171 and the external slider 172 are coupled by magnetic force, so the external slider 172 also moves to the same position. The light shielding plate 177 fixed to the external slider 172 with the fixing rod 181 moves in the same manner to cover a part of the opening 180, and the amount of light transmitted through the opening 180 is reduced.
[0108]
Therefore, by comparing the amount of light transmitted through the opening 180 and the opening 179, it can be determined to which direction and how much the internal slider 171 has moved. The opening degree of the needle valve 43 is controlled by a control device (not shown) so as to return the internal slider 171 to the original center position.
[0109]
The position detector 200 for comparing the light amount of the pressure adjuster 70 has the same configuration and function as the detector 120 of the differential pressure detector 53.
[0110]
In this way, the opening amount of the needle valve 43 is controlled so that the internal slider 171 is always at the center position, and the amount of oxygen released from the oxygen release port 45 or the amount of hydrogen supplied from the hydrogen supply port 55 is determined. By adjusting, high-pressure hydrogen can be generated without applying a differential pressure to the water electrolysis cell 1.
[0111]
Even if the control is performed as described above, if the pressure in the hydrogen high-pressure vessel 2 continues to be higher than the pressure in the oxygen high-pressure vessel 62 and the movement of the internal slider 171 cannot be stopped, the internal slider 171 is spring-loaded. If the spring 171 is not pressed when hitting 183, the internal slider 171 cannot move any further, so there is no restriction on the movement of the internal slider 171 while the internal slider 171 moves to this position, so almost no differential pressure is generated. do not do.
[0112]
However, when the internal slider 171 hits the spring 183, it cannot move any further unless the internal slider 171 pushes the spring 183. That is, although the differential pressure cannot be adjusted by the movement of the internal slider 171, by providing the bypass flow path 174, if the differential pressure becomes larger than that, the spring 183 contracts, and the pure water in the hydrogen high-pressure vessel 2 is reduced. The oxygen does not flow directly into the oxygen high-pressure vessel 62 via the bypass channel 174, and the differential pressure does not increase beyond a certain level.
[0113]
If the pure water in the hydrogen high-pressure vessel 2 flows directly into the oxygen high-pressure vessel 62 via the bypass channel 174, some abnormality occurs, and the needle valve 43 by the control device (not shown) is generated. In such an abnormal situation, the emergency stop is performed, the power supply 61 of the water electrolysis cell 1 is shut off, and all except the valve 58 are closed. An emergency shut-off switch (not shown) and emergency discharge valves 47 and 58 are provided to stop the generation of hydrogen and oxygen from the water electrolysis cell 1 and to rapidly reduce the pressure of the hydrogen high-pressure vessel 2.
[0114]
Although not shown in FIG. 5, in order to stop the apparatus safely, nitrogen piping is provided so that the oxygen high-pressure vessel 62 and the hydrogen high-pressure vessel 2 are replaced with nitrogen gas.
[0115]
In addition, the strength of the springs 182 and 183 is set so that the internal slider 171 pushes the spring 183 and the differential pressure at which pure water flows into the bypass flow path 173 or 174 is within the allowable pressure resistance of the water electrolysis cell 1. This is one means for preventing the water electrolysis cell 1 from being damaged by receiving a pressure higher than the pressure resistance even in such an emergency stop.
[0116]
Further, when the volume of the hollow cylinder 170 is made equal to the volume of the oxygen reservoir 52 in the oxygen high-pressure vessel 62 excluding the volume of the internal slider 171, the ± 50% differential pressure is eliminated before the emergency shutoff is activated. Can do.
[0117]
7 and 8 are partial cross-sectional views of other pressure regulators 70. The pressure regulator 70 shown in these figures is a pressure regulator instead of the bypass flow path 173 or 174 of the previous pressure regulator 70. FIG. In parallel with the vessel 70, a pure water pipe 213 having a shut-off valve 220 in the middle, and switches 211 and 212 for operating the opening and closing thereof are provided.
[0118]
In these pressure regulators 70, when the differential pressure becomes larger than can be adjusted by the movement of the internal slider 171 and the internal slider 171 contracts the spring 183, the internal slider 171 is provided at the end. The shut-off valve 220 is opened by the switches 211 and 212, for example, pure water in the hydrogen high-pressure vessel 2 is directly flowed into the oxygen high-pressure vessel 62 via the pure water pipe 213, and the differential pressure becomes larger than a certain level. It functions so as not to do.
[0119]
【The invention's effect】
In the high-pressure hydrogen production method and apparatus of the present invention, pure water existing in both the hydrogen high-pressure vessel and the oxygen high-pressure vessel is used, and the differential pressure between hydrogen and oxygen is a predetermined value (the allowable pressure resistance of the water electrolysis cell). The pressure in the container is adjusted so that the pressure does not exceed the pressure of the vessel, making it easy to control the pressure, and without using a compressor, only by electrolysis of water, It is very easy to manufacture.
[0120]
Moreover, since the pure water used for pressure adjustment is a part of pure water supplied to the anode side where oxygen is generated in the hydrogen high-pressure vessel, it penetrates the cathode side where hydrogen is generated. Pure water is supplied naturally without the need to supply special water, and it is effective to use what has been treated as unnecessary in the past. It is an effective differential pressure control means that can efficiently control the differential pressure with a small amount of pure water discharge.
[0121]
Furthermore, the higher the pressure of the generated hydrogen and oxygen, the lower the differential pressure with a small amount of pure water. Therefore, the optimum effect can be expected when applied to the production of high-pressure hydrogen necessary for the use of hydrogen energy.
[0122]
In the present invention, the amount of pure water in the hydrogen high-pressure vessel is made larger than the volume of the portion in which oxygen is stored in the oxygen high-pressure vessel, and the amount of pure water in the oxygen high-pressure vessel is increased to the hydrogen in the hydrogen high-pressure vessel. By making it larger than the volume of the portion where hydrogen is stored, it is possible to reliably prevent hydrogen and oxygen from mixing and generating squealing.
[0123]
Furthermore, it is possible to reduce the oxygen storage amount to 4% or less of the hydrogen storage amount, even if mixed, or below the lower explosion limit. A large amount of pure water and a small amount of oxygen can be added to the oxygen high-pressure vessel. By storing a small amount of pure water and a large amount of hydrogen in the container, respectively, and increasing the amount of pure water in the hydrogen high-pressure container to be larger than the volume of oxygen stored in the oxygen high-pressure container, By making the amount of pure water in the high-pressure vessel larger than the volume of the hydrogen storage portion in the hydrogen high-pressure vessel, oxygen on the oxygen high-pressure vessel side leaks and the pressure drops due to equipment failure or any inconvenience However, even if an accident occurs in which pure water in the hydrogen high-pressure vessel flows into the oxygen high-pressure vessel, the oxygen in the oxygen high-pressure vessel must be completely leaked and replaced with pure water. Does not flow into the pure water oxygen container. On the other hand, even if hydrogen leaks and the pressure in the hydrogen high-pressure vessel decreases and pure water in the oxygen high-pressure vessel flows in, all the hydrogen in the hydrogen high-pressure vessel is replaced with pure water in the oxygen high-pressure vessel. Otherwise, oxygen in the oxygen high-pressure vessel will not flow into the hydrogen high-pressure vessel, so that accidents in which squeal is generated can be avoided.
[0124]
In addition, in the present invention, instead of the conventional float-type water level gauge, a water level gauge that detects the water level by using the fact that the electrical conductivity characteristics of a gas such as oxygen and pure water are greatly different should be used. Therefore, even if the density difference between high-pressure oxygen and pure water becomes small, the water surface can be detected stably with high accuracy, and the limit of the generated pressure due to the float being crushed by high-pressure hydrogen or oxygen is eliminated. did.
[0125]
As described above, according to the present invention, it is possible to automatically control the pressure difference between hydrogen and oxygen generated in water electrolysis within the pressure resistance of the water electrolysis cell. The required high-pressure hydrogen can be produced safely, stably and inexpensively without using a mechanical compressor, and its practical and economic effects are immense.
[Brief description of the drawings]
FIG. 1 is a layout view of a high-pressure hydrogen production apparatus according to an embodiment of the present invention.
FIG. 2 is a partial cross-sectional view showing the structure of a differential pressure detector used in the present invention.
FIG. 3 is a cross-sectional view (a) and a side view (b) showing the structure of an open valve used in the present invention.
FIG. 4 is a sectional view showing the structure of a water level meter used in the present invention.
FIG. 5 is a layout view of a high-pressure hydrogen production apparatus according to another embodiment of the present invention.
FIG. 6 is a partial sectional view (a) of a pressure regulator used in the present invention and a sectional view taken along line AA ′ of FIG.
FIG. 7 is a partial cross-sectional view of another pressure regulator used in the present invention.
FIG. 8 is a partial sectional view of another pressure regulator used in the present invention.
[Explanation of symbols]
1 Water electrolysis cell
2 Hydrogen high-pressure vessel
5,6 heat exchanger
8,17 Opening valve
16a, 16b Pure water piping
28,33 Ion exchange resin cylinder
35 resistivity meter
40 Pure water supply tank
41 High-pressure pure water supply tank
50 Water level gauge
53 Differential pressure detector
62 Oxygen high pressure vessel
70 Pressure regulator

Claims

When electrolyzing pure water to generate hydrogen by a water electrolysis cell comprising a solid polymer electrolyte membrane,
Using a pipe for communicating the pressure difference between the hydrogen high-pressure container for storing the generated hydrogen and the oxygen high-pressure container for storing oxygen with the pure water existing in these containers, A high-pressure hydrogen production method characterized by adjusting by moving to one side.

When electrolyzing pure water to generate hydrogen by a water electrolysis cell comprising a solid polymer electrolyte membrane,
A pipe for communicating the pressure difference between the hydrogen high-pressure container for storing the generated hydrogen and the oxygen high-pressure container for storing oxygen, adjusting the hydrogen pressure and oxygen pressure of each container, and pure water existing in the containers. used, high-pressure hydrogen production method and controlling by moving the pure water present in said each container, to either side.

The pressure difference is
The high-pressure hydrogen production method according to claim 1, wherein the pressure is suppressed to a pressure equal to or lower than that of the water electrolysis cell.

The movement of the pure water is
3. The high-pressure hydrogen production method according to claim 1 or 2, wherein the high-pressure hydrogen production method is performed by operating an open valve connected to a pure water pipe connecting the hydrogen high-pressure vessel and the oxygen high-pressure vessel.

The operation of the release valve is as follows:
The high pressure hydrogen production method according to claim 4, wherein the open valve is immersed in pure water in the container.

The movement of the pure water is
3. The high-pressure hydrogen production method according to claim 1, wherein the high-pressure hydrogen production method is automatically performed by a pressure regulator provided in a pure water pipe connecting the hydrogen high-pressure vessel and the oxygen high-pressure vessel.

The movement of the pure water is
3. The high-pressure hydrogen production method according to claim 1, wherein the high-pressure hydrogen production method is performed by opening and closing a valve provided in a pure water pipe connecting the hydrogen high-pressure vessel and the oxygen high-pressure vessel.

In the high pressure hydrogen production method according to claim 1 or 2,
The pure water volume stored in the hydrogen high-pressure vessel is larger than the oxygen volume stored in the oxygen high-pressure vessel, and the pure water volume stored in the oxygen high-pressure vessel is larger than the hydrogen volume stored in the hydrogen high-pressure vessel. A high-pressure hydrogen production method characterized by being performed while being controlled.

In the high pressure hydrogen production method according to claim 1 or 2,
A method for producing high-pressure hydrogen, wherein the amount of oxygen stored in the oxygen high-pressure vessel is controlled within 4% of the amount of hydrogen stored in the hydrogen high-pressure vessel.

A water electrolysis cell comprising a solid polymer electrolyte membrane, a hydrogen high-pressure vessel for storing generated hydrogen and pure water accompanying hydrogen, an oxygen high-pressure vessel for storing raw material and return pure water and generated oxygen, and a pure hydrogen in the hydrogen high-pressure vessel Pure water piping for differential pressure adjustment that communicates water and pure water in the oxygen high-pressure vessel, and differential pressure for sensing the pressure difference between hydrogen and oxygen in the hydrogen high-pressure vessel and oxygen high-pressure vessel and controlling the pressure difference Provide a detector

A water electrolysis cell comprising a solid polymer electrolyte membrane, a hydrogen high-pressure vessel for storing generated hydrogen and pure water accompanying hydrogen, an oxygen high-pressure vessel for storing raw pure water and generated oxygen, and pure water in a hydrogen high-pressure vessel Provided in the pure water piping for differential pressure adjustment that connects the pure water in the oxygen high pressure vessel and the pure water piping, and slides according to the pressure difference between the pure water in the hydrogen high pressure vessel and the pure water in the oxygen high pressure vessel An apparatus for producing high-pressure hydrogen, comprising a pressure regulator having a slider therein.

The water electrolysis cell is
The high-pressure hydrogen production apparatus according to claim 10 or 11, which is installed in a hydrogen high-pressure vessel or a pure water oxygen high-pressure vessel.

The high-pressure hydrogen production apparatus according to claim 10 or 11,
A high-pressure pure water supply tank and a pure water replenishing tank above the oxygen high-pressure vessel, a water feed pump connecting the bottoms thereof, an ion exchange resin cylinder, a pure water circulation feed pipe having a filter, and a high-pressure pure water supply tank The pure water circulation return pipe connecting the upper part of the pure water supply tank and the upper part of the pure water supply tank, the oxygen supply pipe connecting the upper part of the oxygen high pressure container and the upper part of the high pressure pure water supply tank, and the pure water connecting the bottom of the high pressure pure water supply tank and the inside of the oxygen high pressure container A high-pressure hydrogen production apparatus comprising a pure water production / supply system in which water injection pipes are arranged.

Pure water piping for communicating pure water in the hydrogen high-pressure vessel and pure water in the oxygen high-pressure vessel,
11. The high-pressure hydrogen production apparatus according to claim 10, comprising: a pipe having an open valve in a hydrogen high-pressure vessel and a pipe having an open valve in an oxygen high-pressure vessel.

The release valve is
The high-pressure hydrogen production apparatus according to claim 14, wherein the high-pressure hydrogen production apparatus has a discharge port that is triangular when viewed from the front.

The differential pressure detector is
Both ends are sealed with bellows that expands and contracts in the axial direction under the pressure of a hydrogen high-pressure vessel or oxygen high-pressure vessel, and a cylinder made of a nonmagnetic material filled with an inert fluid inside, and in close contact with the inner surface of the cylinder. Detection of differential pressure based on the position of the external magnetic body changed due to the expansion and contraction of the bellows, and the apparatus main body consisting of an internal magnetic body provided on the outer surface, and an external magnetic body provided in close contact with the outer surface. The high-pressure hydrogen production apparatus according to claim 10, comprising a vessel.

The differential pressure detector is
It is composed of a light shielding plate that moves in conjunction with an external magnetic material, a display plate having an opening that is shielded by the light shielding plate, and a photoelectric meter that converts the amount of light transmitted through the opening into an electrical signal. The high-pressure hydrogen production apparatus according to claim 16, wherein the apparatus is a high-pressure hydrogen production apparatus.

The differential pressure detector is
17. The high-pressure hydrogen production apparatus according to claim 16, further comprising a slider that slides on the electric resistor in conjunction with an external magnetic body.

The pressure regulator is
A hollow cylinder made of a non-magnetic material with one end communicating with pure water in the hydrogen high-pressure vessel and the other end communicating with pure water in the oxygen high-pressure vessel, blocking both pure water and closely contacting the inner surface of the hollow cylinder Position detection for detecting the position of the external slider and an apparatus main body comprising an inner slider made of a magnetic material that slides and an outer slider made of a magnetic material that slides in close contact with the outer surface of the hollow cylinder The high-pressure hydrogen production apparatus according to claim 11 or 13, wherein the high-pressure hydrogen production apparatus is constituted by a vessel.

The hollow cylinder is
20. The high-pressure hydrogen production apparatus according to claim 19, wherein springs are provided at both ends, and the internal slider has flow paths at both ends when pure water is circulated when sliding to the ends.

The hollow cylinder is
It has springs at both ends, and an internal slider has a switch at both ends that opens and closes a shut-off valve provided in a pipe through which pure water is circulated that slides to the end. The high pressure hydrogen production apparatus according to claim 19.

The hollow cylinder is
The volume of hydrogen stored in the hydrogen high-pressure vessel and the amount of oxygen stored in the oxygen high-pressure vessel are equal to the smaller volume, or a substantial volume less than that, The high pressure hydrogen production apparatus according to claim 19.

The high pressure hydrogen production apparatus according to any one of claims 10 to 22,
A high-pressure hydrogen production apparatus comprising a water level meter having a center electrode and a cylindrical electrode centered on the center electrode.

The water level gauge is
A main electrode having concentric outer electrodes arranged outside the rod-shaped center electrode, and a sub-electrode having concentric outer electrodes arranged outside the rod-shaped center electrode covered with an electrically insulating cylinder except for the tip The high-pressure hydrogen production apparatus according to claim 23.

The high pressure hydrogen production apparatus according to any one of claims 10 to 23,
A high-pressure hydrogen production apparatus comprising a normally open hydrogen emergency release valve in a hydrogen high-pressure vessel, a normally open oxygen emergency release valve in a pure water oxygen high-pressure vessel, and an emergency power shut-off switch in the power source of a water electrolysis cell .