産総研による二酸化炭素と水で作る液体合成燃料はガソリン、軽油、ジェット燃料など内燃機関向けの燃料を代替する。
https://newstsukuba.jp/54719/06/12/
https://newstsukuba.jp/54719/06/12/
https://aon.tokyo/pdf/newstsukuba_jp.pdf
https://aon.tokyo/pdf/newstsukuba_jp.pdf
水素を常温で運用するには、マグネシウムと水素や、トルエンと水素を結合させてメチルシクロヘキサン（MCH）に変換する「メチルシクロヘキサン（MCH）方式」や常温で、水素を使用せずにアンモニアを製造する方法もあり、
産業技術総合研究所 (AIST): 常温・常圧でのアンモニアの連続電解合成で世界最高性能を達成
東京大学: モリブデン触媒を用いたアンモニア合成技術の開発
出光興産: 常温常圧電解アンモニア合成で世界最高性能を達成
より詳しい情報を知りたい場合は、
以下の検索ワードで、
検索してみてください。
常温アンモニア合成
モリブデン触媒
電解アンモニア合成
カーボンフリーアンモニア
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https://neovisionconsulting.blogspot.com/2024/11/20240708.html
https://neovisionconsulting.blogspot.com/2024/11/20240708.html
出光などが「世界最高性能」、
常温常圧で水素不要のアンモニア合成
野澤 哲生
日経クロステック/日経エレクトロニクス
2024.07.08 有料会員限定
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https://neovisionconsulting.blogspot.com/2024/11/20230127.html
https://neovisionconsulting.blogspot.com/2024/11/20230127.html
アンモニア合成に大変革、
東大などが空気と太陽光のみで実現へ
野澤 哲生 日経クロステック／
日経エレクトロニクス 2023.01.27
有料会員限定
---
そのアンモニアから水素を得たり、ロケット燃料にもなる過酸化水素（オキシドール）発電などで済むかも知れません。PHEVや発電所に利用出来るのではないでしょうか？
水素を常温、常圧で輸送するには、 トルエンと水素を結合させてメチルシクロヘキサン（MCH）に変換する「メチルシクロヘキサン（MCH）方式」が御座います。
水素は常温常圧では気体の状態にあり、体積が大きく、貯蔵や輸送にコストがかかるため、大量の水素を長距離で運搬するには運搬しやすい形に変換する必要があります。水素の常温輸送には、次のような方法が考えられています。
- トルエンと水素を結合させてメチルシクロヘキサン（MCH）に変換する「メチルシクロヘキサン（MCH）方式」。トルエンやMCHは常温・常圧で液体状態のままケミカルタンカーやタンクローリー車などで運ぶことができ、体積が500分の1になるという利点があります。また、MCHは修正液の溶剤など身近なところで使用される化学物質で、化学物質としてのリスクが低いです。ENEOSホールディングスは、2025年度にもこの方式の実用化を目指して大型装置の開発を進めています。
- 水素を液化して輸送する「液化水素方式」。豪州と日本が実施したパイロット水素サプライチェーン実証事業では、水素を超低温に冷却・液化して水素運搬船で日本まで運んでいます。
- アンモニアを利用した「アンモニア方式」。
【新技術】赤錆光触媒！水素と過酸化水素製造に成功！ コメント：この技術は、上水道に使うには良いと思います。海水の場合は、ハロゲンと言う不純物を取り除きながら、淡水化処理をしないで、海水から直接、水素や過酸化水素を得る日本の特許が御座います。＆ 海水から過酸化水素水の製造方法及び装置の特許。元のタイトルは、過酸化水素水の製造方法及び装置
海水から過酸化水素水の製造方法及び装置の特許。元のタイトルは、過酸化水素水の製造方法及び装置
https://patents.google.com/patent/JP3677078B2/ja
JP3677078B2
Japan
- Other languages
English - Inventor
孝之 島宗 保夫 中島 修平 脇田 高弘 芦田 善則 錦 - Current Assignee
- Katayama Chemical Works Co Ltd
- De Nora Permelec Ltd
Description
【産業上の利用分野】
本発明は、塩水、主として海水を原料として過酸化水素水を電気化学的に製造する方法及び装置に関する。
【０００２】
【従来技術とその問題点】
過酸化水素は、食品、医薬品、パルプ、繊維、半導体工業において不可欠の基礎薬品として有用であり、従来はアントラキノン法により合成されている。
従来から、例えば冷却水として海水を使用する発電所や工場では、復水器内部への生物付着を防止するために、海水を直接電解して次亜塩素酸を生成させ、該次亜塩素酸を有効利用することが試みられている。しかし次亜塩素酸をそのまま放流することは次亜塩素酸自体、及び分解により生成する有機塩素化合物や塩素ガスが有毒で環境保全上問題があり、その規制が強化されつつある。
【０００３】
一方微量の過酸化水素を前記冷却水中に添加すると、良好な生物付着防止効果があることが報告され、又養魚場の水質維持にも過酸化水素の添加が効果的であるという報告がなされている。しかも過酸化水素は分解しても無害な水と酸素に変換されるのみで環境衛生上の問題も生じない。
しかしながら過酸化水素は不安定であり、長期間の保存が不可能であるため、又輸送に伴う安全性、汚染対策の面から、オンサイト型装置の需要が高まっている。
【０００４】
このような要請に応えるために従来から種々の過酸化水素の製法が提案されている。米国特許第3,592,749 号には数種類の電解装置が提案され、又米国特許第4,384,931 号にはアルカリ性過酸化水素水の製法としてイオン交換膜を用いる電解法が開示されている。更に米国特許第3,969,201 号には三次元構造のカーボン陰極とイオン交換膜から成る過酸化水素の製造装置が記載されているが、得られる過酸化水素の濃度に対してアルカリ濃度が大きくなり、用途に制限が生ずる。更に特公昭59−15990 号には多孔性の隔膜材料と疎水性カーボン陰極を用いる過酸化水素の製法が開示されているが、これらの方法では陽極室から陰極室への電解質溶液の移行量や速度の制御が困難で運転が煩雑である。
【０００５】
又陽イオン交換膜及び陰イオン交換膜を用いて３室に区画した電解槽の中間室に硫酸を供給し酸性の過酸化水素水を安定的に得る方法〔Journal of Electrochemical Society, vol.130, p1117(1983)〕や陽極として膜と電極の接合体を使用することにより高性能で過酸化水素を得る方法が提案されている。しかしながらこれらの方法では電力原単位が掛かり経済性に問題がある。しかもこれらの方法ではいずれも過酸化水素がアルカリ水溶液雰囲気で効率良く得られるため、原料としてのアルカリ成分を供給する必要があり、この大量のアルカリ水溶液の輸送にも問題がある。
このように現在に至っても十分に満足できる電解による過酸化水素製造方法及び装置は得られていない。
【０００６】
【発明の目的】
本発明は、塩水を原料としてオンサイトで過酸化水素を高効率で製造するための方法及び装置を提供することを目的とする。
【０００７】
【問題点を解決するための手段】
本発明は、塩水を電解してアルカリ水溶液を製造し、該アルカリ水溶液及び酸素含有ガスを加えながら水を電解して過酸化水素を含むアルカリ水溶液を製造することを特徴とする過酸化水素水の製造方法、及び該方法に使用可能な過酸化水素水の製造装置である。
【０００８】
以下本発明を詳細に説明する。
本発明では、第１段階として塩化ナトリウム水溶液や塩化カリウム水溶液等の塩水、好ましくは海水を電解してアルカリ水溶液を製造し、第２段階として第１段階で得られたアルカリ水溶液及び酸素含有ガスを添加しながら水を電解して過酸化水素を含むアルカリ水溶液を得る。この第２段階で第１段階で生成したアルカリ水溶液を添加するのは過酸化水素の生成効率を高めるためである。即ち中性、酸性域では、単にＯ2 の４電子還元つまりＯ2 ＋２Ｈ2 ０＋４ｅ→４ＯＨ- が進行し、Ｈ2 Ｏ2 を得ることが困難になる。なおアルカリ水溶液の濃度が高過ぎると生成苛性ソーダは問題がないが、アルカリ濃度が高いためにその用途が限られることがある。
【０００９】
第１電解槽は、２枚のイオン交換膜を使用して電解槽を陽極室−中間室−陰極室の３室に区画した３室型電解槽でも、１枚のイオン交換膜を使用して陽極室と陰極室に区画した２室型電解槽のいずれでも良い。
３室型電解槽を使用する場合には陽極室と中間室を陰イオン交換膜を使用して区画し陰極室と中間室を陽イオン交換膜を使用して区画し、中間室に塩水を供給しながら通電を行なう。中間室に供給された塩水中のナトリウムイオン等が陽イオン交換膜を透過して陰極室に達し、水の電解還元により生成する水酸イオンと結合して水酸化アルカリを生成し、陰極液がアルカリ水溶液となる。なおこの通常の陰極反応では水素が発生するが、酸素ガスを供給しながら電解を進行させることにより水素を水に変換して水素の発生を抑制して槽電圧の低減を図ることができる。
【００１０】
一方中間室に供給される塩水中の塩素イオンは陰イオン交換膜を透過して陽極室に達し、塩素ガスや次亜塩素酸を発生する。塩素ガスや次亜塩素酸の生成を望まない場合は中間室と陽極室を区画するイオン交換膜として陽イオン交換膜を使用すれば良く、塩素イオンは陽極室へも陰極室へも透過できず、陽極側から供給される水素イオンと共に塩酸になり酸性塩水として中間室から排出される。この陽イオン交換膜で陽極室と中間室を区画する態様では、陽極室で通常の水の電解酸化による酸素発生が生じるが、前述の陰極反応と同様に水素ガスを供給しながら電解を進行させることにより発生する酸素を水に変換して酸素の発生を抑制して槽電圧の低減を図ることができる。
前記第１電解槽における陽極反応及び陰極反応は次の通りである。
陽極：２Ｈ2 ０→Ｏ2 ＋４Ｈ+ ＋４ｅ 又は Ｈ2 →２Ｈ+ ＋２ｅ
陰極：２Ｈ2 ０＋２ｅ→Ｈ2 ＋２ＯＨ- 又は Ｏ2 ＋Ｈ2 Ｏ＋４ｅ→４ＯＨ-
なお第１電解槽として前述の２室型電解槽を使用する場合には、塩水を陽極室に供給しながら電解を行ない、陰極室でアルカリ水溶液を得る。しかし陽極室で塩素ガスが発生するため、後述するアルカリ性を中和するための酸性塩水は得られない。
【００１１】
次いで前記陰極室で生成したアルカリ水溶液を第２電解槽に供給する。該第２電解槽は、１枚のイオン交換膜等の隔膜で陽極室及び陰極室に区画した２室型電解槽があることが好ましく、隔膜として中性膜又は陰イオン交換膜を使用する場合には前記アルカリ水溶液は陽極室及び陰極室のいずれに供給しても良く、隔膜として陽イオン交換膜を使用する場合には陰極室に供給する。
陰極室に酸素含有ガスを供給しながら通電すると下記の反応式に従って陰極室で過酸化水素が生成する。
陽極：２Ｈ2 ０→Ｏ2 ＋４Ｈ+ ＋４ｅ 又は Ｈ2 →２Ｈ+ ＋２ｅ
陰極：Ｏ2 ＋Ｈ2 ０＋２ｅ→ＯＨ- ＋ＨＯ2 - （過酸化水素）
【００１２】
第２電解槽で得られる過酸化水素は同時に生成する水酸イオンを含むアルカリ水溶液に溶解しているためアルカリ性水溶液として得られるが、中性領域の水溶液が望ましい場合には、第１又は第２電解槽の陽極室で得られる酸性水と混合すれば良い。
次に前述の各電解槽を構成する部材及び運転条件につき説明する。
第１及び第２電解槽とも電極としては通常の板状又は多孔性電極あるいはガス電極のいずれも使用可能である。陽極として使用する板状又は多孔性電極である酸素発生陽極は、チタン、ニオブ、タンタル等の耐食性を有する金網、粉末焼結体、金属繊維焼結体等の基材上に、白金、イリジウム、ルテニウム等の貴金属又はそれらの酸化物から成る触媒を、熱分解法、樹脂による固着法、複合めっき法等により10〜500 ｇ／ｍ2 程度の担持量になるように担持して製造できる。
【００１３】
水素発生陰極の場合も同様に、白金、イリジウム、ルテニウム等の貴金属又はそれらの酸化物から成る触媒を熱分解法等により、ニッケル焼結体等の基材上に１〜500 ｇ／ｍ2 程度の担持量になるように担持して製造できる。
水素ガス陽極の場合は、チタン、ニオブ、タンタル、カーボン等の耐食性を有する網状体、粉末焼結体、繊維焼結体等の基材上に、白金、イリジウム等の貴金属又はそれらの酸化物又はカーボンから成る触媒を、熱分解法、樹脂による固着法、複合めっき法等により10〜500 ｇ／ｍ2 程度の担持量になるように担持して製造できる。反応生成ガス、液の供給、除去を速やかに行なうために疎水性や親水性の材料を分散担持することが好ましい。
【００１４】
酸素ガス陰極の場合も同様に、ステンレス、ジルコニウム、銀、カーボン等の耐食性を有する網状体、粉末焼結体、繊維焼結体等の基材上に、金、銀、白金、イリジウム等の貴金属又はそれらの酸化物及び／又はカーボンから成る触媒を、熱分解法、樹脂による固着法、複合めっき法等により10〜500 ｇ／ｍ2 程度の担持量になるように担持して製造できる。水素ガス陽極の場合と同様に疎水性や親水性の材料を分散担持することが好ましい。
使用するイオン交換膜はフッ素樹脂系、炭化水素樹脂系のいずれでも良いが、耐食性の面から前者が望ましい。イオン交換膜は、陽極及び陰極で生成した各イオンが対極で消費されるのを防止するとともに、本発明のように液の電導度が低い場合でも電解を速やかに進行させる機能を有する。
【００１５】
前述のガス電極の場合、イオン交換膜と陰極の間に陰極液室、陽極と該膜の間に陽極液室を設けても良いが、液の電導度が低い場合、槽電圧の増加となり、又槽構造が複雑になり、各ガス電極の気液分離性能が必要となる等不利な点が多い。従って電極をイオン交換膜に接合する構造が最も好ましい。本発明の場合、陽極室を実質的なガス室とすることができるが、陰極室ではアルカリ水溶液や過酸化水素水が生成するため、気液混合状態となる。
電極とイオン交換膜を接合させる必要がある場合には前もってそれらを機械的に結合させておくか、あるいは電解時に圧力を与えれば良い。該圧力としては0.1 〜30ｋｇｆ／ｃｍ2 が好ましい。
【００１６】
原料である水素ガスや酸素ガスは市販ボンベを使用しても良いが、別に設置した電解槽で水の電解により製造したものを使用しても良く、前述の第１電解槽で発生する水素及び酸素ガスを使用することが最も好ましい。別に電解槽を設置する場合には、イオン交換膜の両面に電極を接合し、純水を原料とする電解方式を用いることが好ましい。経済性の観点からこの電解槽を本発明の前述の電解槽と一体化することもできる。本発明の利用分野によっては、この電解槽の陽極からオゾンガスを発生させることも可能であり、エネルギーの有効利用の観点からはこのように構成することが望ましい。
水素の供給量は理論量の1.2 倍程度、酸素の供給量は理論量の1.2 〜100 倍程度が良い。
【００１７】
前述の第１電解槽の中間室の厚さは抵抗損失を低下させるためになるべく薄くすべきであるが、塩水を供給する際のポンプの圧力損失を小さくし圧力分布を均一に保つために１〜10ｍｍとするのが好ましく、又中間室の両側のイオン交換膜が接触しないように絶縁性及び耐食性の優れたスペーサーを挿入することが好ましい。
該第１電解槽における塩水の分解率が大きくなるとプロトンの濃度が増加し陰極側へのナトリウム等の陽イオンの輸率を低下させる。従って前記分解率は40〜80％に維持することが好ましい。この塩水として海水を使用する場合、膜特性に悪影響を及ぼすカルシウム、マグネシウム、重金属イオン、ＳＳ及び固形分を前もって除去してイオン交換膜を保護することが望ましい。この前処理としてはストレーナーやフィルターを設ける以外に、該第１電解槽で生成するアルカリ水溶液の一部を取水口に注入して前記イオンを沈澱させておくことが効果的でありかつ好ましい。
【００１８】
第１電解槽の運転条件は、温度は５〜40℃、電流密度は１〜50Ａ／ｄｍ2 、中間室への供給塩水濃度を20〜300 ｇ／リットルとすることが好ましい。このような条件で生成するアルカリ水溶液の濃度が高過ぎるときはそのまま使用すると前述した通り逆効果となることがあるため、純水で希釈して第２電解槽で必要なアルカリ水溶液濃度に調節することが望ましく、用途にも依存するがｐＨ10以上、濃度35％以下のアルカリ水溶液を添加することが好ましい。第２電解槽の材料は耐久性及び過酸化水素の安定性維持の観点から、ガラスライニング材料、カーボン、耐食性チタン、ステンレス、ＰＴＦＥ樹脂などが好ましい。
なお条件によっては第１及び第２電解槽を一体化しても良い。
【００１９】
次に添付図面に基づいて本発明方法及び装置を例示するが、本発明はこれらに限定されるものではない。
図１は、本発明方法を例示するフローチャートである。
原料である海水１を貯留しかつ固形分を濾過等により除去するためのストレーナー２内の前記海水１がポンプ３により第１電解槽４により供給され、該第１電解槽４で電解されて、アルカリ水溶液と酸性海水が生成する。該第１電解槽４で生成したアルカリ水溶液は一部が循環ライン５を通って前記ストレーナー２に循環され、残りのアルカリ水溶液は供給ライン６により第２電解槽７に供給される。該第２電解槽７では通常の水電解が行なわれるが、該電解槽に供給されたアルカリ水溶液が過酸化水素の生成を促進し、高濃度の過酸化水素が生成し過酸化水素を含有するアルカリ水溶液として第２電解槽７から取り出され、混合用ライン８を通って混合タンク９へ供給される。一方前記第１電解槽４で生成した酸性塩水は迂回ライン10を通って前記混合タンク９へ供給され、前記過酸化水素を含有するアルカリ水溶液と混合されてほぼ中性の過酸化水素水として該混合タンク９から取り出される。
【００２０】
図２は、図１の第１電解槽の縦断面図、図３は、図１の第２電解槽の縦断面図である。
第１電解槽４は、２枚の陽イオン交換膜11及び12により陽極室13、中間室14及び陰極室15に区画され、前記中間室14には網状のスペーサー16が収容されている。前記陽極室13側の陽イオン交換膜11の陽極面側には、チタン等の基材に貴金属酸化物等の触媒を担持して成る多孔性陽極17が、又前記陰極室15側の陽イオン交換膜12の陰極面側には、チタン等の基材に白金等の触媒を担持して成る多孔性陰極18が、それぞれ陽イオン交換膜に密着状態で設置されている。
陽極室下部及び上部側面には、純水供給口19及び陽極液及び酸素ガス取出口20がそれぞれ設置され、又中間室下面及び上面には塩水供給口21及び塩水取出口22がそれぞれ設置され、更に陰極室下部及び上部側面には、純水供給口23及びアルカリ水溶液取出口24がそれぞれ設置されている。
【００２１】
第２電解槽７は、陽イオン交換膜25により陽極室26及び陰極室27に区画され、前記陽イオン交換膜25の陽極室側には、チタン等の基材に貴金属酸化物等の触媒を担持して成る多孔性陽極28が、又前記陽イオン交換膜25の陰極室側にはチタン等の基材に炭素、金等の触媒を担持して成る多孔性陰極29が、それぞれ陽イオン交換膜に密着状態で設置されている。
陽極室上部及び下部側面には、水素ガス及び陽極液供給口30及び陽極液取出口31がそれぞれ設置され、又陰極室下部及び上部側面には、酸素及び前記取出口24から取り出されたアルカリ水溶液の供給口32及び過酸化水素水を含有するアルカリ水溶液取出口33がそれぞれ設置されている。
両電解槽４及び７は図１のフローチャートで示した通りに配置されて、過酸化水素を生成する。
【００２２】
【実施例】
次に本発明による過酸化水素水の製造の実施例を記載するが、該実施例は本発明を限定するものではない。
【実施例１】
それぞれ電極面積が0.2 ｄｍ2 である酸化イリジウム粉末触媒を被覆した気液透過性のチタン製多孔性陽極及び酸化ルテニウム粉末触媒を被覆したニッケル製多孔性陰極を電解槽の陽極室及び陰極室に収容し、前記陽極を陽イオン交換膜ナフィオン117 （デュポン社製）に密着させかつ前記陰極を陽イオン交換膜ナフィオン350 （デュポン社製）に密着させて両陽イオン交換膜間に厚さが３ｍｍの中間室を形成した。該中間室にはポリプロピレン製の網の積層体をスペーサーとして配設し、次いで全体を締め付けて図２に示すような第１電解槽を構成した。
【００２３】
この第１電解槽の陽極室、中間室及び陰極室のそれぞれには順に、純水を毎分１ｃｃ、30ｇ／リットルの塩化ナトリウム水溶液を毎分10ｃｃ及び純水を毎分３ｃｃの割合で供給しながら、温度40℃、電流１Ａで電解を行なったところ、槽電圧は2.5 Ｖであり、陰極室出口からは25ｇ／リットルのアルカリ（水酸化ナトリウム）水溶液が電流効率80％で得られ、又陽極室出口からは25ｇ／リットルの酸性塩水溶液が電流効率80％で得られた。
それぞれ電極面積が0.2 ｄｍ2 である白金触媒を被覆した気液透過性のカーボン製ガス陽極及び金触媒を被覆したカーボン製ガス陰極を、陽イオン交換膜ナフィオン117 （デュポン社製）で区画した電解槽の陽極室及び陰極室に前記陽イオン交換膜に密着するように収容し、全体を締め付けて図３に示すような第２電解槽を構成した。
【００２４】
この第２電解槽の陽極室には前記第１電解槽の陰極室で発生した水素に加えて市販の工業用水素ボンベからの水素ガスを合計毎分10ミリリットルで供給し、一方陰極室には工業用酸素ボンベからの毎分500 ミリリットルの酸素ガス及び前記第１電解槽で生成した25ｇ／リットルのアルカリ水溶液を毎分１ミリリットルの割合で供給しながら、温度30℃、電流１Ａで電解を行なったところ、槽電圧は1.5 Ｖであり、陰極室出口からは10ｇ／リットルの過酸化水素を含むアルカリ水溶液が電流効率95％で得られた。該水溶液を前記第１電解槽で生成した酸性塩水と混合することにより、ほぼ中性の0.5 ％過酸化水素水溶液が毎分10ｃｃの割合で得られた。
【００２５】
【実施例２】
実施例１と同じ第１電解槽を構成し、該第１電解槽の陽極室、中間室及び陰極室のそれぞれに順に、純水を毎分１ｃｃ、30ｇ／リットルの海水を毎分10ｃｃ及び純水を毎分３ｃｃの割合で供給しながら、温度40℃、電流２Ａで電解を行なったところ、槽電圧は4.5 Ｖであり、陰極室出口からは25ｇ／リットルのアルカリ水溶液が電流効率80％で得られ、又陽極室出口からは25ｇ／リットルの酸性海水が電流効率60％で得られた。
このとき生成したアルカリ水溶液の一部を原料海水のタンクに注入し、カルシウム、マグネシウム及び重金属イオンを沈澱させた。ＳＳ及び固形分は前処理としてストレーナーと濾過フィルターにより除去した。
【００２６】
実施例１と同じ第２電解槽を構成し、該第２電解槽の陽極室には、前記第１電解槽の陰極室で発生した水素に加えて市販の工業用水素ボンベからの水素ガスを合計毎分10ミリリットルで供給し、一方陰極室には酸素濃縮装置（日本酸素株式会社製ＯＡ−２Ｌ）からの酸素ガス毎分２リットルと25ｇ／リットルの前記第１電解槽で生成したアルカリ水溶液毎分１ミリリットルの割合で供給しながら、温度30℃、電流１Ａで電解を行なったところ、槽電圧は1.5 Ｖであり、陰極室出口からは10ｇ／リットルの過酸化水素を含むアルカリ水溶液がが電流効率95％で得られた。該水溶液を前記第１電解槽で生成した酸性塩水と混合することにより、ほぼ中性の0.5 ％過酸化水素水溶液が毎分10ｃｃの割合で得られた。
【００２７】
【発明の効果】
本発明方法は、塩水を電解してアルカリ水溶液を製造し、該アルカリ水溶液及び酸素含有ガスを加えながら水を電解して過酸化水素を含むアルカリ水溶液を製造することを特徴とする過酸化水素水の製造方法である。
この本発明方法によると、冷却水や養魚場水等の殺菌に効果のある過酸化水素水が海水等の塩水と純水のみを原料として使用して製造できる。この過酸化水素は従来から海水等の冷却水の殺菌用として使用されている次亜塩素酸と異なり分解しやすく残留することが殆どなく、しかも分解生成物も水と酸素であるため、環境に悪影響を与えることがない。
【００２８】
そして第１段階で製造したアルカリ水溶液を第２段階で添加して過酸化水素の製造を促進しているため、過酸化水素製造の電流効率が上昇し、従来と比較して多量の過酸化水素を得ることができる。又このアルカリ水溶液はオンサントで製造されるため、輸送上の問題が生じない。
更に本発明方法は電解槽及び原料としての塩水及び純水以外を必要としないためオンサイト製造を容易に行なうことができ、製造された過酸化水素をそのまま殺菌等に使用できるため過酸化水素の欠点である分解しやすさも克服できる。又前述の通り原料が塩水と純水のみであるため、殺菌用として過酸化水素が広く使用されている海水を冷却水として使用する際の冷却水及びその装置の場合は純水のみを準備すれば良く、コストが殆ど掛からないだけでなく、輸送も容易で輸送時の物質の分解も考慮する必要がなく、従来の欠点の殆どが解消された画期的な過酸化水素水の製造方法が提供される。
【００２９】
用途によっては中性の過酸化水素水が必要な場合もあるが、本発明の３室型電解では酸性塩水も副生し、この酸性塩水を前述の過酸化水素を含むアルカリ水溶液と混合することによりほぼ中性の過酸化水素を得ることができる。
本発明装置は、塩水を電解してアルカリ水溶液を製造する第１電解槽、及び前記アルカリ水溶液及び酸素含有ガスを供給しながら電解を行ない過酸化水素を含むアルカリ水溶液を製造する第２電解槽を含んで成ることを特徴とする過酸化水素水の製造装置である。
【００３０】
この装置を使用すると前述の本発明方法と同様に従来と比較して多量の過酸化水素を含む水溶液を得ることができる。
そして使用する電極をガス電極とし、水素ガスや酸素ガスを供給しながら電解を行なうとそれぞれ酸素ガス及び水素ガスの発生を抑制して槽電圧の低下を達成できる。
【図面の簡単な説明】
【図１】本発明方法を例示するフローチャート。
【図２】図１の第１電解槽の縦断面図。
【図３】図１の第２電解槽の縦断面図。
【符号の説明】
１・・・海水 ２・・・ストレーナー ３・・・ポンプ ４・・・第１電解槽
７・・・第２電解槽 ９・・・混合タンク 11、12・・・陽イオン交換膜 13・・・陽極室 14・・・中間室 15・・・陰極室 16・・・スペーサー 17・・・多孔性陽極 18・・・多孔性陰極 25・・・陽イオン交換膜 26・・・陽極室
27・・・陰極室 28・・・多孔性陽極 29・・・多孔性陰極
Claims (4)Hide Dependent
- 塩水を電解してアルカリ水溶液を製造し、該アルカリ水溶液及び酸素含有ガスを加えながら水を電解して過酸化水素を含むアルカリ水溶液を製造することを特徴とする過酸化水素水の製造方法。
- 塩水を電解して酸性塩水とアルカリ水溶液を製造し、該アルカリ水溶液及び酸素含有ガスを加えながら水を電解して過酸化水素を含むアルカリ水溶液を製造し、該過酸化水素を含むアルカリ水溶液と前記酸性塩水を混合してｐＨが５から９の過酸化水素を含む水溶液とすることを特徴とする過酸化水素水の製造方法。
- 塩水を電解してアルカリ水溶液を製造する第１電解槽、及び前記アルカリ水溶液及び酸素含有ガスを供給しながら電解を行ない過酸化水素を含むアルカリ水溶液を製造する第２電解槽を含んで成ることを特徴とする過酸化水素水の製造装置。
- 第１電解槽が、２枚のイオン交換膜により多孔性又はガス陽極を有する陽極室、多孔性又はガス陰極を有する陰極室及び両極室間に形成される中間室に区画され、該中間室に塩水を供給し、陽極室で酸性塩水を、陰極室で過酸化水素を含むアルカリ水溶液を得るようにした請求項３に記載の過酸化水素水の製造装置。
Cited By (5)
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ENGLISH VERSION.
About the mysterious power generation device “Holcomb Energy System”. Comment: It is not a perpetual engine, but it appears to be a power amplifier that outputs several times more power than it inputs. With this system, it would be safer than restarting existing nuclear power plants, and would have the advantage of not needing fuel for several decades, which is much safer than a new small nuclear power plant. It could be used for PHEVs and power plants. Translated with DeepL.com (free version)
Hydrogen can also be operated at room temperature using the methylcyclohexane (MCH) method, which combines magnesium and hydrogen or toluene and hydrogen to convert to methylcyclohexane (MCH), or at room temperature to produce ammonia without using hydrogen,
National Institute of Advanced Industrial Science and Technology (AIST): Achieved the world's highest performance in continuous electrolytic synthesis of ammonia at room temperature and pressure
University of Tokyo: Development of ammonia synthesis technology using molybdenum catalysts
Idemitsu Kosan: Achieved the world's highest performance in electrolytic ammonia synthesis at room temperature and pressure
For more information,
Use the following search words,
Search by using the following search words.
room temperature ammonia synthesis
molybdenum catalyst
electrolytic ammonia synthesis
Carbon-free ammonia
---.
https://neovisionconsulting.blogspot.com/2024/11/20240708.html
https://neovisionconsulting.blogspot.com/2024/11/20240708.html
World's highest performance” by Idemitsu and others,
Hydrogen-free ammonia synthesis at room temperature and pressure
Tetsuo Nozawa
Nikkei Crosstec/Nikkei Electronics
2024.07.08 Paid members only
---Nikkei Crosstec, Nikkei Electronics, Inc.
---Nozawa, Tetsuo
https://neovisionconsulting.blogspot.com/2024/11/20230127.html
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A revolution in ammonia synthesis,
Ammonia Synthesis Using Only Air and Sunlight
Tetsuo Nozawa Nikkei Crosstech/
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Paid members only
---Ammonia synthesis
I wonder if it could be used for PHEVs and power plants?
https://www.youtube.com/watch?v=D7dZG07q1j0
https://www.facebook.com/masahiro.ishizuka.54/videos/444802604953193?locale=ja_JP
https://www.linkedin.com/embed/feed/update/urn:li:ugcPost:7260835617515741186
Hydrogen can be transported at room temperature and pressure using the methylcyclohexane (MCH) method, which combines toluene and hydrogen to form methylcyclohexane (MCH).
Hydrogen is in a gaseous state at room temperature and pressure, and its large volume makes it expensive to store and transport, so it must be converted into a form that is easy to transport if a large amount of hydrogen is to be transported over long distances. The following methods are considered for transporting hydrogen at room temperature.
- Methylcyclohexane (MCH) method, in which hydrogen is combined with toluene and converted to methylcyclohexane (MCH). Toluene and MCH can be transported by chemical tankers or tanker trucks in liquid state at room temperature and pressure, and have the advantage of being 1/500th the volume. In addition, MCH is a chemical substance used in everyday life, such as a solvent for correction fluid, and has low risk as a chemical substance; ENEOS Holdings is developing large-scale equipment with the aim of commercializing this method in FY2025.
- The liquefied hydrogen method, in which hydrogen is liquefied and transported. In the pilot hydrogen supply chain demonstration project conducted by Australia and Japan, hydrogen is cooled and liquefied to an ultra-low temperature and transported to Japan by hydrogen carriers.
- Ammonia method” using ammonia.
[New technology] Red rust photocatalyst! Successfully produced hydrogen and hydrogen peroxide! Comment: This technology is good for use in water supply. In case of seawater, there is a Japanese patent to obtain hydrogen and hydrogen peroxide directly from seawater without desalination process while removing impurities called halogen. The patent is for a method and apparatus for producing hydrogen peroxide water from seawater. The original title is Method and apparatus for producing hydrogen peroxide water.
https://www.youtube.com/watch?v=C6fu-yyjCVc
https://www.facebook.com/masahiro.ishizuka.54/videos/703696691808958?locale=ja_JP
https://www.linkedin.com/embed/feed/update/urn:li:ugcPost:7198790864041570305
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Patent for a method and apparatus for producing hydrogen peroxide water from seawater. The original title is Method and apparatus for producing hydrogen peroxide water
https://patents.google.com/patent/JP3677078B2/ja
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JP3677078B2
Japan
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- Inventor
- Takayuki Shimamune
- Yasuo Nakajima
- Shuhei Wakita
- Yoshinori Ashida
- Yoshinori Nishiki
- Current Assignee
- Katayama Chemical Works Co Ltd
- De Nora Permelec Ltd
Worldwide applications
1995 JP
Application JP12057495A events
1995-04-21
Application filed by Katayama Chemical Works Co Ltd, Permelec Electrode Ltd
1995-04-21
1996-11-12 Priority to JP12057495A
2005-07-27 Priority to JPH08296076A
Application granted
Priority to JP12057495A
Publication of JP3677078B2
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Description
0001
Industrial Applications
This invention relates to a method and apparatus for electrochemically producing hydrogen peroxide water from salt water, mainly seawater.
The method and apparatus are based on the conventional technology and its problems.
Conventional technology and its problems
Hydrogen peroxide is useful as an essential basic chemical in the food, pharmaceutical, pulp, textile, and semiconductor industries, and has conventionally been synthesized by the anthraquinone method.
Conventionally, for example, in power plants and factories that use seawater as cooling water, it has been attempted to generate hypochlorous acid by direct electrolysis of seawater and effectively use the hypochlorous acid in order to prevent organisms from adhering to the inside of the condenser. However, discharging hypochlorous acid as it is is problematic for environmental preservation because hypochlorous acid itself, as well as the organic chlorine compounds and chlorine gas generated by its decomposition, are toxic, and regulations are being tightened.
The regulations are being tightened.
On the other hand, it has been reported that the addition of a small amount of hydrogen peroxide to the cooling water has a good anti-adhesion effect, and that the addition of hydrogen peroxide is also effective in maintaining the water quality of fish farms. Moreover, hydrogen peroxide does not cause any environmental health problems, as it only converts into harmless water and oxygen when decomposed.
However, hydrogen peroxide is unstable and cannot be stored for long periods of time.
0004]
To meet this demand, various methods of producing hydrogen peroxide have been proposed in the past. U.S. Patent No. 3,592,749 proposes several types of electrolysis equipment, and U.S. Patent No. 4,384,931 discloses an electrolysis method using an ion exchange membrane as a method of producing alkaline hydrogen peroxide water. U.S. Patent No. 3,969,201 describes a hydrogen peroxide production apparatus consisting of a carbon cathode with a three-dimensional structure and an ion-exchange membrane, but the alkaline concentration is high in relation to the concentration of the hydrogen peroxide obtained, which limits its application. However, the alkaline concentration of the hydrogen peroxide is large in relation to the concentration of the hydrogen peroxide, limiting its use.
0005]
However, it is difficult to control the amount and rate of transfer of the electrolyte solution from the anode chamber to the cathode chamber, and the operation is cumbersome. However, these methods require only a small amount of electricity to produce hydrogen peroxide. However, these methods require a large amount of electricity and have economic problems. Furthermore, since hydrogen peroxide is efficiently obtained in an alkaline solution atmosphere in all of these methods, it is necessary to supply alkaline components as raw materials, and the transportation of this large amount of alkaline solution is also problematic.
Thus, to date, no sufficiently satisfactory method and apparatus for producing hydrogen peroxide by electrolysis have been obtained.
Objectives of the Invention
Purpose of the Invention
It is an object of the present invention to provide a method and apparatus for producing hydrogen peroxide on-site with high efficiency using salt water as a raw material.
[0007] [Problem to be solved
Means for Solving the Problem
This invention is a method for producing hydrogen peroxide water, characterized in that salt water is electrolyzed to produce an alkaline solution, and water is electrolyzed to produce an alkaline solution containing hydrogen peroxide while adding the alkaline solution and oxygen-containing gas, and a device for producing hydrogen peroxide water that can be used for this method.
0008]
The present invention will be described in detail below.
In the present invention, salt water such as sodium chloride solution or potassium chloride solution, preferably seawater, is electrolyzed to produce an alkaline solution as the first step, and water is electrolyzed while adding the alkaline solution obtained in the first step and oxygen-containing gas to obtain an alkaline solution containing hydrogen peroxide as the second step. The reason for adding the alkaline aqueous solution produced in the first step in this second step is to increase the generation efficiency of hydrogen peroxide. In other words, in neutral or acidic regions, the four-electron reduction of O2 (O2 + 2H2 0 + 4e → 4OH- ) proceeds, making it difficult to obtain H2O2 . If the concentration of the alkaline solution is too high, the produced caustic soda is not a problem, but its use may be limited due to the high alkaline concentration.
[0009].
The first electrolyzer can be either a three-chamber electrolyzer, in which two ion-exchange membranes are used to divide the electrolyzer into three chambers (an anode chamber, an intermediate chamber, and a cathode chamber), or a two-chamber electrolyzer, in which one ion-exchange membrane is used to divide the electrolyzer into an anode chamber and a cathode chamber.
When a three-chamber electrolyzer is used, the anode chamber and intermediate chamber are separated by an anion exchange membrane, and the cathode chamber and intermediate chamber are separated by a cation exchange membrane, and the intermediate chamber is energized while brine is supplied to the intermediate chamber. Sodium ions in the salt water supplied to the intermediate chamber permeate the cation exchange membrane and reach the cathode chamber, where they combine with hydroxyl ions generated by the electrolytic reduction of water to form alkali hydroxide, resulting in an alkaline solution in the cathode solution. Hydrogen is generated in this normal cathode reaction, but by supplying oxygen gas while electrolysis proceeds, hydrogen is converted to water and hydrogen generation can be suppressed, thereby reducing the tank voltage.
0010]
On the other hand, chlorine ions in the brine supplied to the intermediate chamber permeate the anion exchange membrane and reach the anode chamber, generating chlorine gas and hypochlorous acid. If the generation of chlorine gas and hypochlorous acid is not desired, a cation exchange membrane can be used as the ion exchange membrane separating the intermediate chamber and the anode chamber. Chlorine ions cannot permeate either the anode chamber or the cathode chamber, and are discharged from the intermediate chamber as acid salt water together with hydrogen ions supplied from the anode side. In this configuration where the anode chamber and intermediate chamber are separated by a cation exchange membrane, oxygen is generated in the anode chamber by the normal electrolytic oxidation of water, but as in the cathode reaction described above, the oxygen generated is converted to water by suppressing oxygen generation while supplying hydrogen gas and allowing electrolysis to proceed, thereby reducing the tank voltage.
The anodic and cathodic reactions in the aforementioned first electrolyzer are as follows.
Anode: 2H2 0 → O2 + 4H+ + 4e or H2 → 2H+ + 2e
Cathode: 2H2 0 + 2e → H2 + 2OH- or O2 + H2 O + 4e → 4OH-
In the case of using the aforementioned two-chamber electrolyzer as the first electrolyzer, electrolysis is performed while supplying salt water to the anode chamber, and an alkaline solution is obtained in the cathode chamber. However, since chlorine gas is generated in the anode chamber, acidic salt water to neutralize alkalinity, as described below, cannot be obtained.
0011]
Next, the alkaline solution generated in the cathode chamber is supplied to the second electrolysis tank. The second electrolyzer is preferably a two-chamber electrolyzer divided into an anode chamber and a cathode chamber by a diaphragm such as an ion exchange membrane, etc. When a neutral membrane or an anion exchange membrane is used as the diaphragm, said alkaline solution may be supplied to either the anode chamber or the cathode chamber, and when a cation exchange membrane is used as the diaphragm Supply to the cathode chamber.
When the cathode chamber is energized while oxygen-containing gas is supplied, hydrogen peroxide is generated in the cathode chamber according to the following reaction formula.
Anode: 2H2 0 → O2 + 4H+ + 4e or H2 → 2H+ + 2e
Cathode: O2 + H2 0 + 2e → OH- + HO2 - ( hydrogen peroxide)
0012]
Hydrogen peroxide obtained in the second electrolysis tank is dissolved in an alkaline solution containing hydroxyl ions that is generated simultaneously, so it is obtained as an alkaline solution. If an aqueous solution in the neutral range is desired, it can be mixed with acidic water obtained in the anode chamber of the first or second electrolysis tank.
Next, the components and operating conditions of each of the aforementioned electrolysis tanks are described.
Both the first and second electrolyzers can use ordinary plate or porous electrodes or gas electrodes as electrodes. The oxygen-evolving anode, which is a plate or porous electrode used as the anode, is composed of a catalyst consisting of precious metals such as platinum, iridium, ruthenium, or their oxides on a base material such as wire mesh, sintered powder, or sintered metal fiber having corrosion resistance of titanium, niobium, tantalum, or the like, by pyrolysis, adherence by resin, composite plating, or other methods. The catalyst can be manufactured by loading a catalyst consisting of precious metals such as platinum, iridium, ruthenium, etc., or their oxides onto a base material such as sintered metal fiber by pyrolysis, adhesion by resin, composite plating, etc. to achieve a loading amount of 10 to 500 g/m2.
0013] The same applies to the hydrogen generating cathode.
Similarly, in the case of a hydrogen generating cathode, a catalyst consisting of precious metals such as platinum, iridium, ruthenium, etc. or their oxides can be manufactured by supporting a catalyst on a base material such as sintered nickel to a loading amount of 1 to 500 g/m2 by a thermal decomposition method, etc.
In the case of hydrogen gas anodes, a catalyst consisting of precious metals such as platinum and iridium, their oxides, or carbon is loaded onto a corrosion-resistant base material such as titanium, niobium, tantalum, carbon, or other corrosion-resistant mesh, powder sintered body, or fiber sintered body by pyrolysis, adhesion by resin, composite plating, or other methods at a loading amount of 10 to 500 g/m2 程度の担持量になるように担持して製造できる。 It is preferable to use hydrophobic or hydrophilic materials as a dispersed support for rapid supply and removal of reaction product gases and liquids.
0014]
Similarly, in the case of oxygen gas cathode, a catalyst consisting of precious metals such as gold, silver, platinum, iridium, etc., or their oxides and/or carbon can be supported on a base material such as stainless steel, zirconium, silver, carbon, or other corrosion-resistant mesh, powder sintered body, or fiber sintered body by pyrolysis, resin adherence, composite plating, or other methods. The catalyst can be produced by loading a catalyst consisting of precious metals such as gold, silver, platinum, iridium, etc., or their oxides and/or carbon onto the base material by pyrolysis, adhesion by resin, composite plating, etc. to achieve a loading amount of 10 to 500 g/m2. As in the case of hydrogen gas anodes, it is preferable to use hydrophobic or hydrophilic materials as dispersion support.
The ion exchange membrane used can be either fluoropolymer or hydrocarbon resin-based, but the former is preferable in terms of corrosion resistance. The ion exchange membrane prevents each ion produced at the anode and cathode from being consumed at the counter electrode, and also has the function of allowing electrolysis to proceed quickly even when the conductivity of the liquid is low, as in the present invention.
[0015].
In the case of the gas electrode described above, a cathode liquid chamber can be provided between the ion exchange membrane and the cathode, and an anode liquid chamber between the anode and the membrane. However, when the conductivity of the liquid is low, the tank voltage increases, the tank structure becomes complex, and the gas-liquid separation performance of each gas electrode is required, which are disadvantages in many respects. Therefore, the structure in which the electrodes are bonded to the ion exchange membrane is most preferable. In the present invention, the anode chamber can be used as the actual gas chamber, but the cathode chamber is a gas-liquid mixture because alkaline solution and hydrogen peroxide water are generated in the cathode chamber.
0016]
The raw materials, hydrogen and oxygen gases, may be produced from commercially available cylinders or from water produced by electrolysis in a separately installed electrolysis tank, and it is most preferable to use the hydrogen and oxygen gases generated in the first electrolysis tank mentioned above. If a separate electrolyzer is installed, it is preferable to use an electrolysis system in which electrodes are bonded to both sides of an ion exchange membrane and pure water is used as the raw material. From an economic standpoint, this electrolyzer can be integrated with the aforementioned electrolyzer of the present invention. Depending on the field of use of the invention, it is also possible to generate ozone gas from the anode of this electrolyzer, and from the viewpoint of effective use of energy, it is desirable to configure it in this way.
The amount of hydrogen supplied should be about 1.2 times the theoretical amount, and the amount of oxygen supplied should be 1.2 to 100 times the theoretical amount.
0017]
The thickness of the intermediate chamber of the first electrolyzer mentioned above should be as thin as possible to reduce resistance loss, but it should be 1 to 10 mm to reduce the pressure loss of the pump when supplying salt water and to maintain uniform pressure distribution. Spacers with excellent insulation and corrosion resistance should be inserted to prevent contact between the ion exchange membranes on both sides of the intermediate chamber.
As the decomposition rate of brine in the first electrolyzer increases, the concentration of protons increases and the rate of sodium and other cations exported to the cathode side decreases. Therefore, it is preferable to maintain the aforementioned decomposition rate at 40-80%. When using seawater as the brine, it is desirable to protect the ion exchange membrane by removing calcium, magnesium, heavy metal ions, SS, and solids that adversely affect membrane properties in advance. For this pretreatment, in addition to providing a strainer and filter, it is effective and preferable to inject a portion of the alkaline solution produced in the first electrolysis tank into the water intake to allow the aforementioned ions to precipitate.
[0018].
The operating conditions of the first electrolysis tank should be as follows: the temperature should be 5 to 40°C, the current density should be 1 to 50 A/dm2 , and the concentration of salt water supplied to the intermediate chamber should be 20 to 300 g/liter. If the concentration of alkaline solution generated under these conditions is too high, using it as it is may have the opposite effect as described above, so it should be diluted with pure water and adjusted to the concentration of alkaline solution required in the second electrolysis tank. It is preferable to add an alkaline solution with a pH of 10 or higher and a concentration of 35% or lower, depending on the application. From the viewpoint of durability and maintaining the stability of hydrogen peroxide, glass lining material, carbon, corrosion-resistant titanium, stainless steel, PTFE resin, etc. are preferred as materials for the second electrolyzer.
Depending on conditions, the first and second electrolyzers may be integrated.
0019]
Next, the inventive method and apparatus are illustrated based on the accompanying drawings, but the invention is not limited thereto.
Figure 1 is a flowchart illustrating the inventive method.
Said seawater 1 in a strainer 2 for storing seawater 1 as raw material and removing solids by filtration, etc. is fed by a pump 3 to a first electrolysis tank 4, and is electrolyzed in said first electrolysis tank 4 to generate an alkaline solution and acid seawater. A portion of the alkaline solution produced in the first electrolysis tank 4 is circulated through the circulation line 5 to the strainer 2, and the remaining alkaline solution is supplied to the second electrolysis tank 7 by the supply line 6. In the second electrolysis tank 7, normal water electrolysis is performed, but the alkaline aqueous solution supplied to the electrolysis tank promotes the generation of hydrogen peroxide, resulting in the generation of highly concentrated hydrogen peroxide, which is taken out of the second electrolysis tank 7 as an alkaline aqueous solution containing hydrogen peroxide and supplied through mixing line 8 to mixing tank 9. On the other hand, the acid salt water generated in the first electrolysis tank 4 is supplied to the mixing tank 9 through the bypass line 10, mixed with the alkaline solution containing hydrogen peroxide, and taken out of the mixing tank 9 as nearly neutral hydrogen peroxide water.
[0020].
Figure 2 is a longitudinal cross-sectional view of the first electrolyzer of Figure 1, and Figure 3 is a longitudinal cross-sectional view of the second electrolyzer of Figure 1.
The first electrolyzer 4 is divided into an anode chamber 13, an intermediate chamber 14, and a cathode chamber 15 by two cation exchange membranes 11 and 12, and said intermediate chamber 14 contains a mesh spacer 16. On the anode side of the cation exchange membrane 11 on the anode chamber 13 side, a porous anode 17 consisting of a catalyst such as a precious metal oxide supported on a base material such as titanium, etc., and on the cathode side of the cation exchange membrane 12 on the cathode chamber 15 side, a porous cathode 18 consisting of a catalyst such as platinum supported on a base material such as titanium, etc., are installed in contact with the cation exchange membrane, respectively. They are installed in close contact with the cathode membrane.
On the lower and upper sides of the anode chamber, there are pure water supply ports 19 and anode solution and oxygen gas outlets 20, respectively; on the lower and upper sides of the intermediate chamber, there are salt water supply ports 21 and salt water outlets 22, respectively; and on the lower and upper sides of the cathode chamber, there are pure water supply ports 23 and alkaline solution outlets 24, respectively. The cathode chamber is equipped with a pure water supply port 23 and an alkaline solution outlet 24.
[0021].
The second electrolyzer 7 is divided into an anode chamber 26 and a cathode chamber 27 by a cation exchange membrane 25. On the cathode chamber side of the cation exchange membrane 25, a porous cathode 29 made of carbon, gold, or other catalyst supported on a base material such as titanium is installed in close contact with the cation exchange membrane.
On the upper and lower sides of the anode chamber, there are supply ports 30 and 31 for hydrogen gas and anode solution, respectively, and on the lower and upper sides of the cathode chamber, there are supply ports 32 for oxygen and alkaline solution taken out from the aforementioned outlet 24 and 33 for alkaline solution containing hydrogen peroxide water, respectively. The electrolysis tanks 4 and 7 are located in the same manner.
Both electrolyzers 4 and 7 are arranged as shown in the flow chart in Figure 1 to produce hydrogen peroxide.
[0022].
Example
Examples of the production of hydrogen peroxide water according to the present invention are described below, but these examples do not limit the present invention.
Example 1
A gas-liquid permeable titanium porous anode coated with iridium oxide powder catalyst and a nickel porous cathode coated with ruthenium oxide powder catalyst, each having an electrode area of 0.2 dm2, are housed in the anode and cathode chambers of an electrolyzer, the anode is attached to a cation exchange membrane Nafion 117 (DuPont) and the cathode is attached to an anion exchange membrane Nafion 117 (DuPont). The cathode was adhered to the cation exchange membrane Nafion 350 (DuPont) to form a 3 mm thick intermediate chamber between the two cation exchange membranes. A laminate of polypropylene mesh was placed in the intermediate chamber as a spacer, and then the whole was tightened to form the first electrolyzer as shown in Figure 2.
[0023].
Electrolysis was conducted at a temperature of 40°C and a current of 1 A while supplying 1 cc of pure water per minute, 10 cc of 30 g/liter sodium chloride solution per minute, and 3 cc of pure water per minute to the anode chamber, intermediate chamber, and cathode chamber of the first electrolyzer, in that order. The voltage of the tank was 2.5 V, and 25 g/liter of alkali (sodium hydroxide) solution was obtained at 80% current efficiency from the outlet of the cathode chamber, and 25 g/liter of acid salt solution was obtained at 80% current efficiency from the outlet of the anode chamber.
A platinum catalyst-coated gas-liquid permeable carbon gas anode and a gold catalyst-coated carbon gas cathode, each with an electrode area of 0.2 dm2, were placed in the anode and cathode chambers of the electrolyzer, which were separated by a cation exchange membrane Nafion 117 (DuPont), in close contact with the cation exchange membrane. The entire structure was tightened to form a second electrolyzer as shown in Figure 3.
[0024].
The anode chamber of the second electrolyzer is supplied with a total of 10 milliliters per minute of hydrogen gas from a commercially available industrial hydrogen cylinder in addition to the hydrogen generated in the cathode chamber of the first electrolyzer, while the cathode chamber is supplied with 500 milliliters per minute of oxygen gas from an industrial oxygen cylinder and 25 g/liter of alkaline solution generated in the first electrolyzer. The voltage was 1.5 V, and an aqueous alkaline solution containing 10 g/liter hydrogen peroxide was obtained from the outlet of the cathode chamber with a current efficiency of 95%. By mixing the aqueous solution with the acid brine generated in the first electrolysis tank, a nearly neutral 0.5% hydrogen peroxide solution was obtained at a rate of 10 cc per minute.
Example 2
Example 2
The same first electrolyzer as in Example 1 was configured, and electrolysis was conducted at a temperature of 40°C and a current of 2 A while supplying 1 cc per minute of pure water, 10 cc per minute of 30 g/liter seawater, and 3 cc per minute of pure water in the anode, intermediate, and cathode chambers of the first electrolyzer, in that order. The tank voltage was 4.5 V, and 25 g/liter of alkaline solution was obtained from the outlet of the cathode chamber with a current efficiency of 80%, and 25 g/liter of acid seawater was obtained from the outlet of the anode chamber with a current efficiency of 60%.
A portion of the alkaline solution was injected into the raw seawater tank to precipitate calcium, magnesium, and heavy metal ions. SS and solids were removed by a strainer and filtration filter as pretreatment.
[0026].
The same second electrolyzer as in Example 1 was configured, and hydrogen gas from a commercial industrial hydrogen cylinder was supplied to the anode chamber of the second electrolyzer at a total rate of 10 milliliters per minute in addition to the hydrogen generated in the cathode chamber of the first electrolyzer, while oxygen gas from an oxygen concentrator (OA-2L manufactured by Oxygen Japan Co.) The cathode chamber was supplied with 2 liters per minute of oxygen gas from an oxygen concentrator (OA-2L manufactured by Oxygen Japan Co., Ltd.) and 1 milliliter per minute of 25 g/liter of alkaline solution generated in the first electrolysis tank. was obtained from the outlet of the cathode chamber with a current efficiency of 95%. By mixing this solution with the acid brine generated in the first electrolysis tank, a nearly neutral 0.5% hydrogen peroxide solution was obtained at a rate of 10 cc per minute.
The result was a nearly neutral 0.5% hydrogen peroxide solution at a rate of 10 cc/minute.
Effects of the Invention
The method of the present invention is characterized in that salt water is electrolyzed to produce an alkaline solution, and water is electrolyzed to produce an alkaline solution containing hydrogen peroxide while adding the alkaline solution and oxygen-containing gas.
According to this method, hydrogen peroxide water effective for sterilizing cooling water, fish farm water, etc. can be produced using only salt water such as seawater and pure water as raw materials. Unlike hypochlorous acid, which has been conventionally used for disinfection of cooling water such as seawater, this hydrogen peroxide is easily decomposed and leaves almost no residue, and since the decomposition products are water and oxygen, there is no adverse effect on the environment.
0028]
The alkaline solution produced in the first stage is added in the second stage to promote the production of hydrogen peroxide, which increases the current efficiency of hydrogen peroxide production and enables the production of a larger amount of hydrogen peroxide than in the past. In addition, since the alkaline solution is produced onsite, there are no transportation problems.
Furthermore, since this method does not require an electrolyzer and raw materials other than salt water and pure water, on-site production can be easily performed, and since the produced hydrogen peroxide can be used as is for sterilization, the disadvantage of hydrogen peroxide, namely, its ease of decomposition, can be overcome. In addition, since the raw materials are only salt water and pure water, as mentioned above, only pure water is required for cooling water and its equipment when using seawater, in which hydrogen peroxide is widely used for sterilization, as cooling water, and the cost is almost zero. This method is easy to transport and does not require consideration of decomposition of substances during transportation.
0029]
In the three-chamber electrolysis of the present invention, acidic salt water is also produced as a byproduct, and by mixing this acidic salt water with the aforementioned alkaline solution containing hydrogen peroxide, an almost neutral hydrogen peroxide can be obtained.
This apparatus is characterized in that it includes a first electrolysis tank for producing an alkaline solution by electrolyzing salt water, and a second electrolysis tank for producing an alkaline solution containing hydrogen peroxide by electrolyzing the aforementioned alkaline solution and oxygen-containing gas while supplying them.
[0030]
When this device is used, an aqueous solution containing a large amount of hydrogen peroxide can be obtained, as in the method of the present invention described above, compared to the conventional method.
Furthermore, if the electrodes used are gas electrodes and electrolysis is performed while supplying hydrogen gas and oxygen gas, the generation of oxygen gas and hydrogen gas, respectively, can be suppressed, thereby achieving a reduction in the cell voltage.
[Brief Description of the Drawings]
[Figure 1] Flowchart illustrating the method of the present invention.
Figure 2] Longitudinal cross-sectional view of the first electrolytic cell in Figure 1.
Figure 3] Longitudinal cross-sectional view of the second electrolytic cell in Figure 1.
[Explanation of symbols]
1: Seawater 2: Strainer 3: Pump 4: First electrolytic cell
7: Second electrolytic cell 9: Mixing tank 11, 12: Cation exchange membrane 13: Anode chamber 14: Intermediate chamber 15: Cathode chamber 16: Spacer 17: Porous anode 18: Porous cathode 25: Cation exchange membrane 26: Anode chamber
27: Cathode chamber 28: Porous anode 29: Porous cathode
Claims (4)
Hide Dependent
A method for producing hydrogen peroxide, comprising electrolyzing salt water to produce an alkaline aqueous solution, and electrolyzing water while adding the alkaline aqueous solution and an oxygen-containing gas to produce an alkaline aqueous solution containing hydrogen peroxide.
A method for producing hydrogen peroxide comprising electrolyzing salt water to produce an acidic salt water and an alkaline aqueous solution, electrolyzing water while adding the alkaline aqueous solution and an oxygen-containing gas to produce an alkaline aqueous solution containing hydrogen peroxide, and mixing the alkaline aqueous solution containing hydrogen peroxide with the acidic salt water to produce an aqueous solution containing hydrogen peroxide having a pH of 5 to 9.
An apparatus for producing hydrogen peroxide comprising a first electrolytic cell for electrolyzing salt water to produce an alkaline aqueous solution, and a second electrolytic cell for performing electrolysis while supplying the alkaline aqueous solution and an oxygen-containing gas to produce an alkaline aqueous solution containing hydrogen peroxide.
The apparatus for producing hydrogen peroxide according to claim 3, wherein the first electrolytic cell is partitioned by two ion exchange membranes into an anode chamber having a porous or gas anode, a cathode chamber having a porous or gas cathode, and an intermediate chamber formed between the two electrode chambers, and salt water is supplied to the intermediate chamber to obtain acidic salt water in the anode chamber and an alkaline aqueous solution containing hydrogen peroxide in the cathode chamber.
Cited By (5)
Publication number Priority date Publication date Assignee Title
Family To Family Citations
EP1036037B1 1997-12-04 2004-02-25 Steris Corporation Chemical modification of electrochemically activated water
US6409895B1 * 2000-04-19 2002-06-25 Alcavis International, Inc. Electrolytic cell and method for electrolysis
JP4968628B2 * 2008-04-10 2012-07-04 National University Corporation Niigata University Simultaneous production device for ozone water and hydrogen peroxide water
JP5432103B2 * 2010-09-21 2014-03-05 Masaaki Arai Electrolyzed water production device and its production method
US8882972B2 * 2011-07-19 2014-11-11 Ecolab Usa Inc Support of ion exchange membranes
* Cited by examiner, † Cited by third party, ‡ Family to family citation
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