JP3776647B2

JP3776647B2 - Antifouling device for seawater contact structure and its performance deterioration monitoring method

Info

Publication number: JP3776647B2
Application number: JP29698899A
Authority: JP
Inventors: 垣修一稲; 田繁桜; 島昌二中; 田晃則永; 庭忠彦大
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 1999-10-19
Filing date: 1999-10-19
Publication date: 2006-05-17
Anticipated expiration: 2019-10-19
Also published as: JP2001115427A

Description

【０００１】
【発明の属する技術分野】
本発明は海水に接触する海水接触構造物への海生生物の付着を防止する海水接触構造物の防汚装置に係り、とりわけ、海水接触構造物の海水側表面上に設けられた電気的触媒を介して酸素を発生させることにより海水接触構造物への海生生物の着性を抑制する海水接触構造物の防汚装置およびその性能劣化監視方法に関する。
【０００２】
【従来の技術】
海水を冷却水として取水する発電所においては、熱交換器の管板（伝熱管の入口および出口に位置する支持部材）上に、イガイやフジツボ、ヒドロ虫、海藻類等の生物（以下「海生生物」という）が付着することがある。これらの海生生物は、伝熱管の管端部を塞いで洗浄用スポンジの通過障害となったり、伝熱管の内面を閉塞したりする。このため、このような発電所においては、これらの海生生物の除去作業のためにしばしば操業の停止を余儀なくされている。なお、これらの海生生物は、銅合金製の管板や伝熱管等よりも、耐海水性であるチタン製の管板や伝熱管等に付着しやすい。
【０００３】
また、このような発電所においては、熱交換器の上方に設置された鋼製の水室の側壁に、ストレーナーの網を通り抜けた幼生の海生生物が着生することがある。このような鋼製の水室の表面には通常ゴムライニング等が施されているので、水室の側壁上に着生した海生生物は、水室の側壁上で一定期間成育した後に脱落し、水室の下方に位置する伝熱管の管端部や内面等を閉塞する。
【０００４】
従来においては、これらの海生生物の駆除や付着防止等を行うための防汚対策として、海生生物の防汚に有効な毒性物質を利用する手法が提案されている。このような手法としては例えば、取水した海水中へ塩素や塩素化合物等を投入したり、熱交換器の管板や伝熱管等に毒性イオン生成顔料含有防汚塗料を塗布したり、海水の電解により塩素や銅等の毒性イオンを生成する等の手法がある。
【０００５】
しかしながら、毒性物質を利用する手法では、防汚自体は効果的に行われるが、大量の海水に対する塩素等の毒性物質の量や濃度等の管理が容易でなく、一般には確実な防汚効果を期待してその量や濃度等を過大に設定しやすく、その結果、環境汚染を引き起こす可能性が高い。また、このような毒性物質の使用自体が今日では禁止または抑制される方向にある。
【０００６】
このため、無公害でかつ無毒性の防汚対策の開発が、最近多くの研究者や技術者等によって進められている。具体的には例えば、無公害でかつ無毒性であるが有効な防汚効果を発揮する防汚塗料としてシリコーン系防汚塗料が注目されており、これを熱交換器の管板や伝熱管等に塗布する手法が提案されている。
【０００７】
しかしながら、シリコーン系防汚塗料を利用する手法では、シリコーン系防汚塗料自体に次のような欠点、すなわち貝殻等の異物の接触により防汚寿命が短くなること、施工コストが高いこと、大面積の対象物や既存の施設等への簡単でかつ容易な施工手段がないこと、海水の流れを止めると防汚効果が減少すること等の欠点があることから、広く実用化されるには至っていない。
【０００８】
一方、上述した手法以外の防汚対策として、特公平１−４６５９５号公報および特願平１０−２９２１４２号公報に記載された手法も知られている。
【０００９】
このうち、特公平１−４６５９５号公報に記載された手法は、海水と接触するチタン製部材の表面に、主として白金族金属の混晶、または白金族金属とこれらの金属の酸化物との混合物からなる電気的触媒皮膜を形成し、これを陽極として電解することにより、塩素ガスを実質的に発生させないで十分な酸素を発生させる手法であり、これにより海水中の生物や貝殻等の沈積を抑制することができる。
【００１０】
ところで、このような防汚対策が講じられる熱交換器は一般に、伝熱管や管板等のみがチタン製部材であり、本体胴や水室、熱交換器へ海水を導く導水管、海水を海へ戻す放水管等は鋼製部材である。また、伝熱管および管板等のチタン製部材と、水室、導水管および放水管等の鋼製部材とは電気的に導通している。
【００１１】
このため、上記特公平１−４６５９５号公報に記載された手法のように、海水と接するチタン製部材の表面に電気的触媒を形成して陽極として作用させる場合には、チタン製部材と導通している水室、導水管および放水管等の鋼製部材も陽極として負荷されることとなる。そして、この状態で、水室、導水管および放水管等の鋼製部材が海水と接触すると、鋼製部材の表面がガルバニ腐食により激しく腐食されることとなる。なお、鋼製部材の表面には通常、腐食防止のためにゴムライニング等が施されているので、このような事態は通常の使用状態では生じないが、仮に、ゴムライニング等が何らかの理由で破損した場合には、この破損部位を介して海水中に電流が流れ水氷室、導水管および放水管等の鋼製部材が異常腐食する可能性がある。
【００１２】
なお、このようなゴムライニング等の破損により生じる異常腐食は通常、陰極防食法を採用して鋼製部材を電気的に鋼材の防食電位まで下げることにより回避することができる。しかしながら、上記特公平１−４６５９５号公報に記載された手法では、チタン製部材が陽極として負荷され、かつ、それに導通している鋼製水室、導水管および放水管等も陽極として負荷されているので、理論上陰極防食法を採用することができない。
【００１３】
これに対し、上記特願平１０−２９２１４２号公報に記載された手法は、このような上記特公平１−４６５９５号公報に記載された手法の欠点を解消するものであり、熱交換器のチタン製管板上に絶縁性接着剤を介して陽極形成部材および電気的触媒を設け、この電気的触媒を介して塩素ガスを実質的に発生させないで十分な酸素を発生させる手法である。これにより、仮に、チタン製管板と導通する鋼製部材を保護するゴムライニング等が何らかの理由で破損した場合でも、陰極防食法を採用して鋼製部材を電気的に鋼材の防食電位まで下げることが可能となり、水室、導水管および放水管等の鋼製部材が異常腐食することを防止することができる。
【００１４】
【発明が解決しようとする課題】
しかしながら、上記特願平１０−２９２１４２号公報に記載された手法では、陽極形成部材および電気的触媒等の耐用状態（健全性および性能劣化等）を十分に把握することができないので、経時的または外的な要因により以下のような問題が生じる。
【００１５】
第１に、陽極形成部材および電気的触媒等を長時間使用した場合に、陽極形成部材および電気的触媒等の性能が劣化し、その性能劣化に起因して海生生物の付着を引き起こすおそれがある。
【００１６】
第２に、絶縁性接着剤が劣化した場合に、陽極形成部材とチタン製管板等との間の電気的絶縁が破れ、それに起因して上記特公平１−４６５９５号公報に記載された手法と同様の問題が生じる。すなわち、陽極形成部材とチタン製管板等との間の電気的絶縁が破れた状態で、チタン製管板等と導通する鋼製部材を保護するゴムライニング等が何らかの理由で破損した場合には、この破損部位を介して海水中に電流が流れ、水室、導水管および放水管等の鋼製部材が異常腐食する可能性があり、信頼性の面で問題がある。
【００１７】
第３に、海水中を漂う導電性異物（例えば針金等）がたまたま熱交換器の伝熱管の入口等に引っかかり、陽極形成部材と伝熱管（すなわちチタン製管板）とが導通した場合に、上述した絶縁性接着剤が劣化した場合と全く同じ事態が生じる可能性があり、信頼性の面で問題がある。
【００１８】
第４に、陽極形成部材および電気的触媒等が大面積を有している場合に、その大面積の陽極形成部材および電気的触媒等の性能劣化がどの部位で起きているのか、また絶縁性接着剤の劣化がどの部位で起きているのか、さらに導電性異物がおおよそどこの部位の伝熱管の入口等に引っかかっているのか等を特定することが難しく、ひとたび不具合が生じると、全ての陽極形成部材および電気的触媒等を更新しなければならず、補修や更新等の保守管理の費用が膨大となるという問題がある。
【００１９】
本発明はこのような点を考慮してなされたものであり、陽極形成部材および電気的触媒等の経時的または外的な要因による問題の発生の有無および部位等を確実かつ容易に把握し、海生生物の付着や、海水と接触する鋼製部材の異常腐食等を未然に防止することができる海水接触構造物の防汚装置およびその性能劣化監視方法を提供することを目的とする。
【００２０】
【課題を解決するための手段】
第１の解決手段は、海水接触構造物への海生生物の着生を抑制する海水接触構造物の防汚装置において、海水接触構造物の海水側表面上に絶縁部を介して設けられた陽極側導電体であって、電気化学的に活性な電気的触媒を有する陽極側導電体と、海水中に設けられた陰極側導電体と、前記陽極側導電体に正極が接続されるとともに前記陰極側導電体に負極が接続された外部電源であって、前記陽極側導電体の前記電気的触媒を介して海水中で酸素を発生させるよう前記正極と前記負極との間の電位を制御する外部電源と、前記陽極側導電体に流れる電流を監視する電流監視装置と、前記電流監視装置による監視結果に基づいて前記陽極側導電体の耐用状態を判定する判定装置とを備えたことを特徴とする海水接触構造物の防汚装置である。
【００２１】
ここで、上述した第１の解決手段においては、前記陽極側導電体は互いに絶縁された複数の陽極側導電体要素からなり、前記電流監視装置は前記各陽極側導電体要素に流れる電流をそれぞれ監視することが好ましい。また、前記判定装置は前記電流監視装置で監視された積算電流値または電流値の変化に基づいて前記陽極側導電体の耐用状態を判定することが好ましい。さらに、前記判定装置は前記電流監視装置で監視された電流値の変化を前記各陽極側導電体要素間で相対的に比較し、その比較結果を考慮しつつ前記各陽極側導電体要素ごとの電流値の変化に基づいて前記各陽極側導電体要素の耐用状態を判定することが好ましい。なお、前記絶縁部は前記海水接触構造物の海水側表面と前記陽極側導電体とを互いに接着するための絶縁性接着剤、前記海水接触構造物の海水側表面と前記陽極側導電体との間に配置された絶縁シート、または前記海水接触構造物の海水側表面に被覆された絶縁体であることが好ましい。また、前記陽極側導電体の前記電気的触媒は白金系金属、白金系金属酸化物、およびコバルトまたはマンガンの酸化物のうちの少なくとも一種を含む単一体、混晶体または複合体であることが好ましい。
【００２２】
第２の解決手段は、海水接触構造物への海生生物の着生を抑制する海水接触構造物の防汚装置の性能劣化監視方法において、海水接触構造物の海水側表面上に絶縁部を介して設けられた陽極側導電体と、海水中に設けられた陰極側導電体との問に電流を流すことにより、前記陽極側導電体の有する電気化学的に活性な電気的触媒を介して海水中で酸素を発生させる工程と、前記酸素発生工程中に前記陽極側導電体に流れる電流を監視する工程と、前記監視工程による監視結果に基づいて前記陽極側導電体の耐用状態を判定する工程とを含むことを特徴とする性能劣化監視方法である。
【００２３】
ここで、上述した第２の解決手段においては、前記陽極側導電体は互いに絶縁された複数の陽極側導電体要素からなり、前記監視工程において、前記各陽極側導電体要素に流れる電流をそれぞれ監視することが好ましい。また、前記判定工程において、前記監視工程で監視された積算電流値または電流値の変化に基づいて前記陽極側導電体の耐用状態を判定することが好ましい。さらに、前記判定工程において、前記監視工程で電流値の急激な増加が監視されたときに、前記陽極側導電体に絶縁不良の可能性があると判定することが好ましい。さらにまた、前記判定工程において、前記陽極側導電体に絶縁不良の可能性があると判定した後、所定時間の経過を待って、または海水接触構造物に対する海水の流れ方向を逆向きにした上で前記陽極側導電体の絶縁不良の有無を再度判定することが好ましい。
【００２４】
さらにまた、前記判定工程において、前記監視工程で電流値の急激な減少が検知されたときに、前記陽極側導電体に剥離または一部破損の可能性があると判定することが好ましい。なお、前記判定工程において、前記監視工程で監視された電流値の変化を前記各陽極側導電体要素間で相対的に比較し、その比較結果を考慮しつつ前記各陽極側導電体要素ごとの電流値の変化に基づいて前記各陽極側導電体要素の耐用状態を判定することが好ましい。
【００２５】
上述した第１および第２の解決手段によれば、陽極側導電体に流れる電流を監視し、陽極側導電体に流れる電流の積算電流値または電流値の変化に基づいて陽極側導電体の耐用状態（健全性および性能劣化等）を判定するので、陽極側導電体の耐用状態を確実に把握し、陽極側導電体の性能劣化に起因した海生生物の付着を未然に防止することができる。また、絶縁部が劣化した場合や、海水中を漂う導電性異物が海水接触構造物に引っかかった場合等に生じる絶縁不良現象に起因した、海水と接触する鋼製部材の異常腐食等を未然に防止することができる。
【００２６】
また、陽極側導電体を互いに絶縁された複数の陽極側導電体要素に分割し、各陽極側導電体要素に流れる電流をそれぞれ監視することにより、陽極側導電体が大面積を有している場合でも、その大面積の陽極側導電体の性能劣化がどの部位で起きているのか等を容易に特定することができ、補修や更新等の保守管理を簡易かつ安価に行うことができる。
【００２７】
【発明の実施の形態】
以下、図面を参照して本発明の実施の形態について説明する。
【００２８】
図１は本発明による海水接触構造物の防汚装置の一実施の形態を示す図である。図１に示すように、海水接触構造物の防汚装置１は、海水１５に接するチタン製の熱交換器（海水接触構造物）２への海生生物の着生を抑制するためのものであり、陽極側導電体４、陰極側導電体８、外部直流電源（外部電源）７、電流監視装置９および判定装置１０を備えている。なお、熱交換器２は、チタン製の管板２ａと、この管板２ａにより支持された複数のチタン製の伝熱管２ｂとを有している。また、熱交換器２には、内面にゴムライニング１１が施された鋼製の水室１３が設置されている。
【００２９】
図１に示すように、熱交換器２の海水１５側表面に位置する管板２ａの略全面上には、絶縁性接着剤（絶縁部）３を介して陽極側導電体４が設けられている。陽極側導電体4は、厚さが０．１〜０．３ｍｍの陽極形成部材５と、陽極形成部材５上に被覆された電気的触媒６とを有している。このうち、電気的触媒６は、電気化学的に活性で安定な触媒であり、陽極形成部材５上にあらかじめ触媒被覆処理によって被覆され、電気抵抗加熱等により３５０〜４５０℃で数時間加熱処理を行って熱活性化処理されたものである。なお、電気的触媒６としては、例えば、白金系金属、白金系金属酸化物、およびコバルトまたはマンガンの酸化物のうちの少なくとも一種を含む単一体、混晶体または複合体を用いることができる。
【００３０】
また、絶縁性接着剤３および陽極側導電体４は、複数の伝熱管２ｂの管径に対応する複数の開孔を有している。また、陽極側導電体４は、互いに絶縁された複数の陽極側導電体要素４ａ，４ｂ（陽極形成部材要素５ａ，５ｂおよび電気的触媒要素６ａ，６ｂ）からなっており、隣接する陽極側導電体要素４ａ，４ｂ同士は絶縁性接着剤１７を介して絶縁されている。なお、隣接する陽極側導電体要素４ａ，４ｂ同士の絶縁方法としては、これ以外にも、絶縁部材を介して陽極側導電体要素４ａ，４ｂ同士を重ね合わせたり、防汚効果が得られる範囲で陽極側導電体要素４ａ，４ｂ同士を所定距離だけ離間させたりする方法を用いることができる。
【００３１】
一方、熱交換器２に設置された水室１３の側壁上には、ゴムライニング１１から海水１５側に向かって陰極側導電体８および照合電極１２が突出して設けられている。
【００３２】
ここで、陽極側導電体４および陰極側導電体８はそれぞれ、外部直流電源（外部電源）７の正極７ａおよび負極７ｂに接続されている。また、照合電極１２は外部直流電源７の照合極７ｒに接続されている。なお、陽極側導電体４は複数の陽極側導電体要素４ａ，４ｂからなっているので、各陽極側導電体要素４ａ，４ｂごとに対応する正極７ａが設けられている。外部直流電源７は、自動電位制御部７ｃを内蔵しており、陽極側導電体４の電気的触媒６を介して海水１５中で塩素ガスを実質的に発生させないで酸素を発生させるよう、正極７ａと負極７ｂとの間に形成される通電回路の電位を制御することができるようになっている。なお、正極７ａと負極７ｂとの間に形成される通電回路の具体的な電位値としては、標準海水で塩素ガスを発生させる塩素発生電位（ＳＣＥ）１．１３Ｖよりも低く、かつ標準海水で酸素を発生させる酸素発生電位０．５２Ｖよりも高い値が用いられる。また、正極７ａと負極７ｂとの間に形成される通電回路の具体的な電流値としては、電気的触媒６の種類によって若干の違いはあるが通常０．３〜３．０Ａ／ｍ^２程度の値が用いられる。なお、照合電極１２の電位値は、海水１５の電位により自動電位制御部７ｃを校正するために用いられる。
【００３３】
また、外部直流電源７の各正極７ａには電流監視装置９が接続されており、各陽極側導電体要素４ａ，４ｂに流れる電流をそれぞれ監視することができるようになっている。
【００３４】
さらに、電流監視装置９には判定装置１０が接続されており、電流監視装置９からの出力データ（各陽極側導電体要素４ａ，４ｂに流れる電流の積算電流値または電流値の変化）に基づいて各陽極側導電体要素４ａ，４ｂの耐用状態（健全性および性能劣化等）を判定することができるようになっている。なお、判定装置１０は、電流監視装置９で監視された電流値の変化を各陽極側導電体要素４ａ，４ｂ間で相対的に比較し、その比較結果を考慮しつつ各陽極側導電体要素４ａ，４ｂごとの電流値の変化に基づいて各陽極側導電体要素４ａ，４ｂの耐用状態を判定する。なお、判定装置１０での判定結果は外部直流電源７に出力され、外部直流電源７から各陽極側導電体要素４ａ，４ｂへの電流供給の遮断等に用いられるようになっている。
【００３５】
次に、このような構成からなる本実施の形態の作用について説明する。
【００３６】
図１において、外部電流電源７を介して陽極側導電体４（陽極形成部材５および電気的触媒６）と陰極側導電体８との間に電流を流す。なおこのとき、外部直流電源７の自動電位制御部７ｃの制御の下で各陽極側導電体要素４ａ，４ｂと陰極側導電体８との間の電位は０．５２〜１．１３Ｖの範囲に保たれ、かつその電流値は０．３〜３．０Ａ／ｍ^２程度に保たれる。これにより、電気的触媒６を介して海水１５中で塩素ガスを実質的に発生させないで酸素を発生することができ、熱交換器２の管板２ａおよび伝熱管２ｂへの海生生物の着生を防止することができる。
【００３７】
このとき、各陽極側導電体要素４ａ，４ｂに流れる電流は電流監視装置９によりそれぞれ監視され、各陽極側導電体要素４ａ，４ｂに流れる電流についての積算電流値または電流値の変化に基づいて各陽極側導電体要素４ａ，４ｂの耐用状態（健全性および性能劣化等）が判定される。
【００３８】
図２は図１に示す判定装置１０における具体的な判定方法を説明するための図である。
【００３９】
図２に示すように、判定装置１０においては、まず、電流監視装置９からの出力データを取り込み、各陽極側導電体要素４ａ，４ｂに流れる電流の積算電流値または電流値の変化を取得する（ステップ１０１）。
【００４０】
次に、各陽極側導電体要素４ａ，４ｂに流れる電流の積算電流値が所定値を越えているか否かを判断し（ステップ１０２）、各陽極側導電体要素４ａ，４ｂの中でそれに流れる電流の積算電流値が所定値を越えているものが存在している場合には、該当する陽極側導電体要素４ａ，４ｂの電気的触媒６ａ，６ｂが消耗しているものと判定する（ステップ１０３）。
【００４１】
ここで、各陽極側導電体要素４ａ，４ｂの各電気的触媒要素６ａ，６ｂは積算電流値に比例して溶解および消耗するので、積算電流値に対する消耗量を電気的触媒の厚さ（μｍ）に換算することにより、各電気的触媒要素６ａ，６ｂの消耗寿命を算出することができる（図３参照）。具体的には例えば、電気的触媒がコバルト系触媒である場合には、積算電流値に対する消耗量は５２０ｍｇ／Ａ・年と予測することができ、電気的触媒の厚さを０．５μｍとすると、積算電流値が１６．７Ａ・年を越えたところで消耗することが分かる。なお、この場合には、電流値１．０Ａ／ｍ^２で連続通電した場合に約８年で消耗する。このため、このような消耗寿命を考慮してステップ１０２における所定値を設定することにより、各電気的触媒６ａ，６ｂの消耗状態を適切に判定することが可能である。
【００４２】
一方、ステップ１０２において、各陽極側導電体要素４ａ，４ｂに流れる電流の積算電流値が所定値を越えていないと判断された場合には、ステップ１０４の処理へ進み、各陽極側導電体要素４ａ，４ｂに流れる電流値の変化が所定範囲を越えて行われているか否かを調べる。
【００４３】
ステップ１０４において、各陽極側導電体要素４ａ，４ｂの中でそれに流れる電流値の変化が所定範囲を越えて行われているものが存在している場合には、ステップ１０５の処理へ進み、各陽極側導電体要素４ａ，４ｂに流れる電流値の変化が経時的なものであるか否かをさらに判断する。一方、各陽極側導電体要素４ａ，４ｂに流れる電流値の変化が所定範囲内で行われている場合には、ステップ１０１の処理に戻り、上述した処理を繰り返す。
【００４４】
なお、ステップ１０５において、該当する陽極側導電体要素４ａ，４ｂに流れる電流値の変化が経時的なものであると判断された場合には、該当する陽極側導電体要素４ａ，４ｂの陽極形成部材５ａ，５ｂが性能劣化したものと判定する（ステップ１０６）。
【００４５】
ここで、各陽極側導電体要素４ａ，４ｂの各陽極形成部材５ａ，５ｂの性能が劣化すると、各陽極側導電体要素４ａ，４ｂと陰極側導電体８との間の電位を所定値に保つために必要とされる電流値が低下してくる（図４（ａ）（ｂ）参照）。このため、各陽極側導電体要素４ａ，４ｂに流れる電流値の変化を監視することにより、各陽極形成部材５ａ，５ｂの性能劣化を適切に判定することが可能である。なお、各陽極形成部材５ａ，５ｂの性能劣化により電流値が低下すると、それに比例して各電気的触媒要素６ａ，６ｂからの酸素の発生量も低下するので、海生生物に対する防汚効果自体も当然に低下することになる。具体的には、各陽極側導電体要素４ａ，４ｂに流れる電流値の初期値の１／５〜１／１０程度まで電流値が低下した場合に各陽極形成部材５ａ，５ｂが性能劣化したものと判定するようにするとよい。なおこのとき、各陽極側導電体要素４ａ，４ｂに流れる電流値は、海水性状等の外的な要因、例えば赤潮や汚染海水の流入等によって変動することがあるので、電流監視装置９で監視された電流値の変化を各陽極側導電体要素４ａ，４ｂ間で相対的に比較し、その比較結果を考慮しつつ各陽極側導電体要素４ａ，４ｂごとの電流値の変化に基づいて各陽極側導電体要素４ａ，４ｂの各陽極形成部材５ａ，５ｂの性能劣化を判定するようにするとよい。
【００４６】
一方、ステップ１０５において、該当する陽極側導電体要素４ａ，４ｂに流れる電流値の変化が経時的なものでないと判断された場合には、ステップ１０７の処理へ進み、該当する陽極側導電体要素４ａ，４ｂに流れる電流値が急激に増大したか否かを判断する（ステップ１０７）。
【００４７】
ステップ１０７において、該当する陽極側導電体要素４ａ，４ｂに流れる電流値の急激な増加が検知されたときには、該当する陽極側導電体要素４ａ，４ｂの陽極形成部材５ａ，５ｂに絶縁不良の可能性があると判定する（ステップ１０８）。
【００４８】
ここで、各陽極側導電体要素４ａ，４ｂに流れる電流値の急激な増加は、絶縁性接着剤３が劣化した場合や、海水１５中を漂う導電性異物（例えば針金等）が伝熱管２ｂの入口等に引っかかり、各陽極形成部材要素５ａ，５ｂと伝熱管２ｂ（すなわち管板２ａ）とが導通した場合に引き起こされる絶縁不良現象であり、各陽極側導電体要素４ａ，４ｂに流れる電流値の変化を監視することにより判定することができる。しかし、後者の場合には、海水１５中を漂う導電性異物（例えば針金等）が一時的に伝熱管２ｂの入口等に引っかかり、その後、流出してしまう場合も多い。
【００４９】
このため、各陽極側導電体要素４ａ，４ｂに流れる電流値の急激な増加を検知した場合には、所定時間の経過を待って電流値の変化を検知し、各陽極側導電体要素４ａ，４ｂの各陽極形成部材要素５ａ，５ｂの絶縁不良の有無を再度判定するようにするとよい。具体的には、図５（ａ）（ｂ）に示すように、最初の急激な電流値の増加によって、各陽極側導電体要素４ａ，４ｂに絶縁不良の可能性があると判定し、一旦各陽極側導電体要素４ａ，４ｂへの電流供給を遮断した後（時間Ａ）、数秒から数１０秒の経過を待って時間Ｂのタイミングで各陽極側導電体要素４ａ，４ｂへの電流供給を再開する。このとき、電流値の急激な増加が検知されない場合には、各陽極側導電体要素４ａ，４ｂの絶縁不良の可能性がないと判定する（図５（ａ）参照）。一方、再び電流値の急激な増加がある場合には、各陽極側導電体要素４ａ，４ｂの絶縁不良の可能性があると判定し、時間Ｃのタイミングで各陽極側導電体要素４ａ，４ｂへの電流供給を遮断する（図５（ｂ）参照）。
【００５０】
なお、海水１５中を漂う導電性異物（例えば針金等）は、海水１５の流れ方向を逆向きにすると流出することが多いので、各陽極側導電体要素４ａ，４ｂに流れる電流値の急激な増加を検知した場合において、熱交換器２に対する海水１５の流れ方向を逆向きにした上で各陽極側導電体要素４ａ，４ｂの絶縁不良の有無を再度判定するようにしてもよい。
【００５１】
一方、ステップ１０７において、該当する陽極側導電体要素４ａ，４ｂに流れる電流値の急激な減少が検知されたときには、該当する陽極側導電体要素４ａ，４ｂの面積の減少によるものであるので、該当する陽極側導電体要素４ａ，４ｂに打痕や摩耗等による剥離または一部破損の可能性があると判定する（ステップ１０９）。
【００５２】
このように本実施の形態によれば、陽極側導電体４に流れる電流を電流監視装置９により監視し、陽極側導電体４に流れる電流の積算電流値または電流値の変化に基づいて陽極側導電体４の耐用状態（健全性および性能劣化等）を判定装置１０により判定するので、陽極側導電体４の耐用状態を確実に把握し、海生生物の付着や、海水１５と接触する鋼製部材（水室１３等）の異常腐食等を未然に防止することができる。具体的には例えば、陽極側導電体４に流れる電流の積算電流値に基づいて電気的触媒６の消耗状態を判定することにより、電気的触媒６を長時間使用した場合における性能劣化を未然に予測することができ、電気的触媒６の性能劣化に起因した海生生物の付着を防止することができる。また、陽極側導電体４に流れる電流値の変化に基づいて陽極形成部材５の性能劣化を判定することにより、陽極形成部材５を長時間使用した場合における性能劣化を未然に予測することができ、陽極形成部材５の性能劣化に起因した海生生物の付着を防止することができる。さらに、陽極側導電体４に流れる電流値の変化（電流値の急激の増加）に基づいて、絶縁性接着剤３が劣化した場合や、海水１５中を漂う導電性異物（例えば針金等）が伝熱管２ｂの入口等に引っかかった場合に生じる絶縁不良の有無を確実に把握することにより、海水１５と接触する鋼製部材（水室１３等）の異常腐食を未然に防止することができる。さらにまた、陽極側導電体４に流れる電流値の変化（電流値の急激の減少）に基づいて、陽極側導電体４の剥離または一部破損を確実に判定することにより、陽極側導電体４が流出して熱交換器２や水室１３等に悪影響を及ぼすことを効果的に防止することができる。
【００５３】
また、本実施の形態によれば、陽極側導電体４を互いに絶縁された複数の陽極側導電体要素４ａ，４ｂに分割し、電流監視装置９により各陽極側導電体要素４ａ，４ｂに流れる電流をそれぞれ監視するので、陽極側導電体４（陽極形成部材５および電気的触媒６）が大面積を有している場合でも、その大面積の陽極形成部材５および電気的触媒６の性能劣化がどの部位で起きているのか、また絶縁性接着剤３の劣化がどの部位で起きているのか、さらに導電性異物がおおよそどこの部位の伝熱管２ｂの入口等に引っかかっているのか等を容易に特定することができ、補修や更新等の保守管理を簡易かつ安価に行うことができる。
【００５４】
さらに、本実施の形態によれば、各陽極側導電体要素４ａ，４ｂ間で電流値の変化を相対的に比較し、その比較結果を考慮しつつ各陽極側導電体要素４ａ，４ｂごとの電流値の変化に基づいて前記各陽極側導電体要素４ａ，４ｂの耐用状態を判定するので、海水性状等の外的な要因による電流偵の変動の影響を除外して陽極側導電体４の耐用状態を精度良く判定することができる。
【００５５】
さらにまた、本実施の形態によれば、陽極側導電体４に流れる電流値の急激な増加を検知した場合には、所定時間の経過を待って電流値の変化を検知し、陽極側導電体４の陽極形成部材５の絶縁不良の有無を再度判定するので、海水１５中を漂う導電性異物が一時的に伝熱管２ｂの入口等に引っかかり、その後流出した場合等における絶縁不良誤動作を防止することができる。なおこのとき、陽極側導電体４の陽極形成部材５の絶縁不良の有無を再度判定する前に海水１５の流れ方向を逆向きにすることにより、海水１５中を漂う導電性異物を効果的に流出させることができる。
【００５６】
なお、本実施の形態によれば、電気的触媒６があらかじめ被覆された陽極形成部材５を、絶縁性接着剤３を介して常温で管板２ａ上に接着しているので、電気的触媒６の触媒活性のために必要とされる、３５０〜４５０°での数時間の電気抵抗加熱処理等を管板２ａ上で行う必要がなくなり、発生熱や熱応力等により管板２ａが損傷する危険性を効果的に回避することができる。
【００５７】
なお、上述した実施の形態においては、熱交換器２の管板２ａ上に絶縁性接着剤３を介して陽極側導電体４を設けているが、図６に示すように、絶縁性接着剤３と陽極側導電体４との間に絶縁シート１８を配置するようにしてもよい。これにより、管板２ａと陽極側導電体４との間の電気的絶縁を強固に実現することができる。なお、この場合には、管板２ａと絶縁シート１８との間、および絶縁シート１８と陽極側導電体４との間を接着するための接着剤は必ずしも絶縁性を有している必要はない。
【００５８】
また、上述した実施の形態においては、熱交換器２の管板２ａ上に陽極側導電体４を設けているが、これに限らず、海水接触構造物にあらかじめ設けられている絶縁体上に陽極側導電体４を設けるようにしてもよい。具体的には例えば、図７に示すように、海水接触構造物である水室１３の表面に施されたゴムライニング（絶縁体）１１上に接着剤１６を介して陽極側導電体４を設けることができる。また、図８に示すように、海水接触構造物であるコンクリート製取水路１４上に接着剤１６を介して陽極側導電体４を設けることができる。なお、図８に示す場合には、冷却用海水取入れコンクリート製取水路１４の補強用鉄筋（一部が海水１５と接触している）が導電体８として作用する。また、図７および図８に示すいずれの場合も、ゴムライニング１１およびコンクリート製取水路１４が絶縁性を有していることから、接着剤１６自体は絶縁性を有している必要はない。なお、図７および図８に示すゴムライニング１１およびコンクリート製取水路１４に限らず、海水接触構造物に設けられた樹脂材等の種々の絶縁体上にも同様にして陽極側導電体４を設けることが可能である。
【００５９】
【発明の効果】
以上説明したように本発明によれば、陽極側導電体に流れる電流を監視し、陽極側導電体に流れる電流の積算電流値または電流値の変化に基づいて陽極側導電体の耐用状態（健全性および性能劣化等）を判定するので、陽極側導電体の耐用状態を確実に把握し、陽極側導電体の性能劣化に起因した海生生物の付着を未然に防止することができる。また、絶縁部が劣化した場合や、海水中を漂う導電性異物が海水接触構造物に引っかかった場合等に生じる絶縁不良現象に起因した、海水と接触する鋼製部材の異常腐食等を未然に防止することができる。
【００６０】
また、陽極側導電体を互いに絶縁された複数の陽極側導電体要素に分割し、各陽極側導電体要素に流れる電流をそれぞれ監視することにより、陽極側導電体が大面積を有している場合でも、その大面積の陽極側導電体の性能劣化がどの部位で起きているのか等を容易に特定することができ、補修や更新等の保守管理を簡易かつ安価に行うことができる。
【図面の簡単な説明】
【図１】本発明による海水接触構造物の防汚装置の一実施の形態を示す概略図。
【図２】図１に示す海水接触構造物の防汚装買の性能劣化監視方法を説明するためのフローチャート。
【図３】図１に示す海水接触構造物の防汚装置における電気的触媒の消耗状態の判定の仕方を説明するための図。
【図４】図１に示す海水接触構造物の防汚装置における陽極形成部材の性能劣化の判定の仕方を説明するための図。
【図５】図１に示す海水接触構造物の防汚装置において電流値の急激な増加が検知された場合の陽極形成部材の判定の仕方を説明するための図。
【図６】図１に示す海水接触構造物の防汚装置の一変形例を示す概略図。
【図７】図１に示す海水接触構造物の防汚装置の別の変形例を示す概略図。
【図８】図１に示す海水接触構造物の防汚装置のさらに別の変形例を示す概略図。
【符号の説明】
１海水接触構造物の防汚装置
２熱交換器
２ａ管板
２ｂ伝熱管
３絶縁性接着剤（絶縁部）
４陽極側導電体
５陽極形成部材
６電気的触媒
７外部直流電源（外部電源）
７ａ正極
７ｂ負極
７ｒ照合極
７ｃ自動電位制御部
８陰極側導電体
９電流監視装置
１０判定装置
１１ゴムライニング（絶縁体）
１２照合電極
１３水室
１４コンクリート製取水路（絶縁体）
１５海水
１６接着剤
１７絶縁性接着剤
１８絶縁シート（絶縁部）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antifouling device for a seawater contact structure that prevents adhesion of marine organisms to a seawater contact structure that contacts seawater, and in particular, an electrocatalyst provided on a seawater side surface of the seawater contact structure. The present invention relates to an antifouling device for a seawater contact structure that suppresses the attachment of marine organisms to the seawater contact structure by generating oxygen and a method for monitoring performance deterioration thereof.
[0002]
[Prior art]
In power plants that take seawater as cooling water, mussels, barnacles, hydro-insects, seaweeds and other organisms (hereinafter “sea”) are placed on the heat exchanger tube plates (support members located at the inlet and outlet of the heat transfer tubes). May be attached). These marine organisms block the tube ends of the heat transfer tubes and obstruct the passage of the cleaning sponge, or block the inner surface of the heat transfer tubes. For this reason, such power plants are often forced to stop operations for the removal of these marine organisms. These marine organisms are more likely to adhere to a titanium tube plate or heat transfer tube that is seawater resistant than a copper alloy tube plate or heat transfer tube.
[0003]
Moreover, in such a power plant, larval marine organisms that have passed through the strainer net may settle on the side wall of a steel water chamber installed above the heat exchanger. Since the surface of such a steel water chamber is usually provided with rubber lining, marine organisms that have grown on the side wall of the water chamber fall off after growing for a certain period on the side wall of the water chamber. The tube ends and inner surfaces of the heat transfer tubes located below the water chamber are closed.
[0004]
Conventionally, as an antifouling measure for controlling these marine organisms or preventing adhesion thereof, a method using a toxic substance effective for antifouling of marine organisms has been proposed. Examples of such methods include throwing chlorine or chlorine compounds into the drawn seawater, applying antifouling paints containing toxic ion-generating pigments to the tube plates and heat transfer tubes of heat exchangers, and electrolysis of seawater. There are techniques such as generating toxic ions such as chlorine and copper.
[0005]
However, in the method using toxic substances, the antifouling itself is effectively performed, but it is not easy to manage the amount and concentration of toxic substances such as chlorine for a large amount of seawater. Expecting that it is easy to set the amount and concentration excessively, and as a result, there is a high possibility of causing environmental pollution. In addition, the use of such toxic substances is now prohibited or suppressed.
[0006]
For this reason, the development of pollution-free and non-toxic antifouling measures has recently been promoted by many researchers and engineers. Specifically, for example, silicone-based antifouling paints are attracting attention as antifouling paints that are non-polluting and non-toxic but exhibit an effective antifouling effect. A method of applying to the surface has been proposed.
[0007]
However, in the method using the silicone antifouling paint, the following disadvantages are caused on the silicone antifouling paint itself, that is, the antifouling life is shortened by contact with foreign matters such as shells, the construction cost is high, the large area There are no simple and easy construction means to the target objects or existing facilities, and there are drawbacks such as reducing the antifouling effect when the seawater flow is stopped, so it has come to be widely put into practical use. Not in.
[0008]
On the other hand, methods described in Japanese Patent Publication No. 1-46595 and Japanese Patent Application No. 10-292142 are also known as antifouling measures other than those described above.
[0009]
Among them, the technique described in Japanese Patent Publication No. 1-46595 is based on the surface of a titanium member that contacts seawater, mainly a mixed crystal of a platinum group metal, or a mixture of a platinum group metal and an oxide of these metals. This is a method of generating sufficient oxygen without substantially generating chlorine gas by forming an electrocatalyst film consisting of the above and electrolyzing it as an anode, thereby reducing the deposition of organisms and shells in seawater. Can be suppressed.
[0010]
By the way, in heat exchangers where such antifouling measures are taken, only the heat transfer tubes and tube sheets are generally made of titanium, and the main body, the water chamber, the water conduit that guides seawater to the heat exchanger, The water discharge pipe and the like to return to are a steel member. Moreover, titanium members, such as a heat exchanger tube and a tube sheet, and steel members, such as a water chamber, a water conduit, and a water discharge pipe, are electrically connected.
[0011]
For this reason, when an electric catalyst is formed on the surface of a titanium member in contact with seawater to act as an anode, as in the technique described in the above Japanese Patent Publication No. 1-46595, it is electrically connected to the titanium member. Steel members such as water chambers, water conduits and water discharge pipes are also loaded as anodes. And in this state, when steel members, such as a water chamber, a water conduit, and a water discharge pipe, contact with seawater, the surface of steel members will be corroded severely by galvanic corrosion. In addition, since the surface of the steel member is usually provided with rubber lining to prevent corrosion, such a situation does not occur under normal use conditions, but the rubber lining etc. is damaged for some reason. In such a case, an electric current flows in the seawater through the damaged portion, and there is a possibility that steel members such as the water ice chamber, the water conduit, and the water discharge pipe are abnormally corroded.
[0012]
Note that such abnormal corrosion caused by damage to the rubber lining or the like can usually be avoided by adopting a cathodic protection method and electrically lowering the steel member to the anticorrosion potential of the steel material. However, in the technique described in the above Japanese Patent Publication No. 1-46595, a titanium member is loaded as an anode, and a steel water chamber, a water conduit, a water discharge pipe, and the like that are connected to the titanium member are also loaded as an anode. Therefore, the cathodic protection method cannot be adopted theoretically.
[0013]
On the other hand, the technique described in the above Japanese Patent Application No. 10-292142 eliminates the drawbacks of the technique described in the above Japanese Patent Publication No. 1-46595, and is a titanium of a heat exchanger. In this method, an anode forming member and an electric catalyst are provided on a tube-making plate via an insulating adhesive, and sufficient oxygen is generated without substantially generating chlorine gas via the electric catalyst. As a result, even if the rubber lining that protects the steel member connected to the titanium tube sheet is broken for some reason, the cathodic protection method is adopted to electrically lower the steel member to the anticorrosion potential of the steel material. It is possible to prevent abnormal corrosion of steel members such as water chambers, water conduits, and water discharge pipes.
[0014]
[Problems to be solved by the invention]
However, the method described in the above Japanese Patent Application No. 10-292142 cannot sufficiently grasp the durability (such as soundness and performance deterioration) of the anode forming member and the electric catalyst. The following problems arise due to external factors.
[0015]
First, when the anode forming member and the electric catalyst are used for a long time, the performance of the anode forming member and the electric catalyst may be deteriorated, and the adhesion of marine organisms may be caused due to the deterioration of the performance. is there.
[0016]
Second, when the insulating adhesive is deteriorated, the electrical insulation between the anode forming member and the titanium tube sheet is broken, and as a result, the technique described in the above Japanese Patent Publication No. 1-46595. The same problem occurs. That is, when the electrical insulation between the anode forming member and the titanium tube sheet etc. is broken, the rubber lining protecting the steel member conducting with the titanium tube sheet etc. is damaged for some reason. The current flows in the seawater through the damaged portion, and the steel member such as the water chamber, the water guide pipe and the water discharge pipe may be abnormally corroded, which is problematic in terms of reliability.
[0017]
Thirdly, when a conductive foreign substance (such as a wire) drifts in seawater happens to be caught in the inlet of the heat transfer tube of the heat exchanger, and the anode forming member and the heat transfer tube (that is, the titanium tube plate) are electrically connected, There is a possibility that exactly the same situation as in the case where the above-described insulating adhesive is deteriorated, and there is a problem in terms of reliability.
[0018]
Fourth, in the case where the anode forming member and the electric catalyst have a large area, where the performance deterioration of the large area anode forming member and the electric catalyst occurs, and insulative properties It is difficult to specify where the adhesive deterioration has occurred, and where the conductive foreign matter is roughly caught by the inlet of the heat transfer tube, etc. There is a problem that the forming member, the electrocatalyst, and the like have to be updated, and the cost of maintenance management such as repair and update becomes enormous.
[0019]
The present invention has been made in consideration of such points, and it is possible to reliably and easily grasp whether or not a problem has occurred due to a temporal or external factor such as an anode forming member and an electrocatalyst, and a site, It is an object of the present invention to provide a seawater contact structure antifouling device and its performance deterioration monitoring method capable of preventing the adhesion of marine organisms and abnormal corrosion of steel members in contact with seawater.
[0020]
[Means for Solving the Problems]
A first solution is an antifouling device for a seawater contact structure that suppresses the formation of marine organisms on the seawater contact structure, and is provided on the seawater side surface of the seawater contact structure via an insulating portion. An anode-side conductor, an anode-side conductor having an electrochemically active electrocatalyst, a cathode-side conductor provided in seawater, and a positive electrode connected to the anode-side conductor and the above-mentioned An external power source in which a negative electrode is connected to a cathode-side conductor, and controls a potential between the positive electrode and the negative electrode so as to generate oxygen in seawater via the electric catalyst of the anode-side conductor. An external power source, a current monitoring device that monitors a current flowing through the anode-side conductor, and a determination device that determines a durability state of the anode-side conductor based on a monitoring result by the current monitoring device. It is an antifouling device for seawater contact structures.
[0021]
Here, in the first solving means described above, the anode-side conductor is composed of a plurality of anode-side conductor elements that are insulated from each other, and the current monitoring device is configured to receive a current flowing through each anode-side conductor element. It is preferable to monitor. Moreover, it is preferable that the said determination apparatus determines the durable state of the said anode side conductor based on the change of the integrated current value or current value monitored by the said current monitoring apparatus. Further, the determination device relatively compares the change in the current value monitored by the current monitoring device between the anode-side conductor elements, and considers the comparison result for each anode-side conductor element. It is preferable to determine the durability state of each anode-side conductor element based on a change in current value. The insulating part is an insulating adhesive for adhering the seawater side surface of the seawater contact structure and the anode side conductor to each other, and the seawater side surface of the seawater contact structure and the anode side conductor. It is preferable that it is an insulation sheet | seat arrange | positioned between them, or the insulator coat | covered on the seawater side surface of the said seawater contact structure. In addition, the electrical catalyst of the anode-side conductor is preferably a single body, a mixed crystal body, or a composite body including at least one of a platinum-based metal, a platinum-based metal oxide, and an oxide of cobalt or manganese. .
[0022]
According to a second solution, in the performance deterioration monitoring method for the antifouling device for a seawater contact structure that suppresses the formation of marine organisms on the seawater contact structure, an insulating portion is provided on the seawater side surface of the seawater contact structure. Through the electrochemically active electrocatalyst possessed by the anode-side conductor, by passing an electric current between the anode-side conductor provided through the cathode and the cathode-side conductor provided in seawater. A step of generating oxygen in seawater; a step of monitoring a current flowing through the anode-side conductor during the oxygen generation step; and determining a durability state of the anode-side conductor based on a monitoring result of the monitoring step. A performance degradation monitoring method characterized by comprising a process.
[0023]
Here, in the second solving means described above, the anode-side conductor is composed of a plurality of anode-side conductor elements insulated from each other, and in the monitoring step, currents flowing through the anode-side conductor elements are respectively determined. It is preferable to monitor. In the determination step, it is preferable to determine the durability state of the anode-side conductor based on the integrated current value or the change in the current value monitored in the monitoring step. Furthermore, in the determination step, it is preferable to determine that the anode-side conductor may have an insulation failure when a rapid increase in current value is monitored in the monitoring step. Furthermore, in the determination step, after determining that the anode-side conductor may have an insulation failure, after waiting for a predetermined time to elapse or reverse the flow direction of seawater with respect to the seawater contact structure. It is preferable to determine again whether or not there is an insulation failure in the anode-side conductor.
[0024]
Furthermore, in the determination step, it is preferable to determine that the anode-side conductor may be peeled off or partially damaged when a sudden decrease in the current value is detected in the monitoring step. In the determination step, the change in the current value monitored in the monitoring step is relatively compared between the anode-side conductor elements, and the results of the comparison are taken into consideration for each anode-side conductor element. It is preferable to determine the durability state of each anode-side conductor element based on a change in current value.
[0025]
According to the first and second solutions described above, the current flowing through the anode-side conductor is monitored, and the durability of the anode-side conductor is determined based on the integrated current value of the current flowing through the anode-side conductor or the change in the current value. Since the state (soundness, performance degradation, etc.) is determined, it is possible to reliably grasp the service life of the anode-side conductor and prevent marine organisms from attaching due to the performance degradation of the anode-side conductor. . In addition, abnormal corrosion of steel members in contact with seawater caused by poor insulation that occurs when the insulation part deteriorates or when conductive foreign matter floating in seawater gets caught in the seawater contact structure, etc. Can be prevented.
[0026]
Further, the anode-side conductor has a large area by dividing the anode-side conductor into a plurality of anode-side conductor elements insulated from each other and monitoring the current flowing through each anode-side conductor element. Even in such a case, it is possible to easily identify in which part the performance deterioration of the anode-side conductor having the large area is occurring, and maintenance management such as repair and update can be performed easily and inexpensively.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0028]
FIG. 1 is a view showing an embodiment of an antifouling device for a seawater contact structure according to the present invention. As shown in FIG. 1, the antifouling device 1 for a seawater contact structure is for suppressing the growth of marine organisms on a titanium heat exchanger (seawater contact structure) 2 in contact with seawater 15. And includes an anode-side conductor 4, a cathode-side conductor 8, an external DC power source (external power source) 7, a current monitoring device 9, and a determination device 10. The heat exchanger 2 has a titanium tube plate 2a and a plurality of titanium heat transfer tubes 2b supported by the tube plate 2a. The heat exchanger 2 is provided with a steel water chamber 13 having an inner surface provided with a rubber lining 11.
[0029]
As shown in FIG. 1, an anode-side conductor 4 is provided on substantially the entire surface of the tube plate 2 a located on the seawater 15 side surface of the heat exchanger 2 via an insulating adhesive (insulating portion) 3. Yes. The anode side conductor 4 has an anode forming member 5 having a thickness of 0.1 to 0.3 mm and an electric catalyst 6 coated on the anode forming member 5. Of these, the electrocatalyst 6 is an electrochemically active and stable catalyst, and is previously coated on the anode forming member 5 by a catalyst coating treatment, and is subjected to a heat treatment at 350 to 450 ° C. for several hours by electric resistance heating or the like. The heat activation treatment was performed. As the electric catalyst 6, for example, a single body, a mixed crystal body, or a composite body including at least one of platinum-based metal, platinum-based metal oxide, and cobalt or manganese oxide can be used.
[0030]
Moreover, the insulating adhesive 3 and the anode side conductor 4 have a plurality of apertures corresponding to the tube diameters of the plurality of heat transfer tubes 2b. The anode-side conductor 4 is composed of a plurality of anode-side conductor elements 4a and 4b (anode-forming member elements 5a and 5b and electrical catalyst elements 6a and 6b) that are insulated from each other. The body elements 4 a and 4 b are insulated from each other through an insulating adhesive 17. In addition, as an insulating method between the adjacent anode-side conductor elements 4a and 4b, a range in which the anode-side conductor elements 4a and 4b are overlapped with each other via an insulating member or an antifouling effect is obtained. Thus, a method of separating the anode-side conductor elements 4a and 4b by a predetermined distance can be used.
[0031]
On the other hand, on the side wall of the water chamber 13 installed in the heat exchanger 2, the cathode-side conductor 8 and the verification electrode 12 protrude from the rubber lining 11 toward the seawater 15.
[0032]
Here, the anode side conductor 4 and the cathode side conductor 8 are connected to the positive electrode 7a and the negative electrode 7b of the external DC power source (external power source) 7, respectively. The verification electrode 12 is connected to the verification electrode 7r of the external DC power supply 7. Since the anode-side conductor 4 is composed of a plurality of anode-side conductor elements 4a and 4b, a positive electrode 7a corresponding to each anode-side conductor element 4a and 4b is provided. The external DC power source 7 has an automatic potential controller 7c built therein, and is positively connected to generate oxygen without substantially generating chlorine gas in the seawater 15 via the electric catalyst 6 of the anode-side conductor 4. The potential of the energization circuit formed between 7a and the negative electrode 7b can be controlled. The specific potential value of the energization circuit formed between the positive electrode 7a and the negative electrode 7b is lower than a chlorine generation potential (SCE) of 1.13 V for generating chlorine gas in standard seawater, and in standard seawater. A value higher than the oxygen generation potential of 0.52 V for generating oxygen is used. The specific current value of the energization circuit formed between the positive electrode 7a and the negative electrode 7b is usually 0.3 to 3.0 A / m, although there are slight differences depending on the type of the electric catalyst 6. ² A degree value is used. Note that the potential value of the verification electrode 12 is used to calibrate the automatic potential control unit 7 c with the potential of the seawater 15.
[0033]
Further, a current monitoring device 9 is connected to each positive electrode 7a of the external DC power supply 7, so that the current flowing through each anode-side conductor element 4a, 4b can be monitored.
[0034]
Further, a determination device 10 is connected to the current monitoring device 9, and based on output data from the current monitoring device 9 (integrated current value of current flowing through each anode-side conductor element 4a, 4b or change in current value). Thus, it is possible to determine the serviceability state (soundness, performance deterioration, etc.) of each anode-side conductor element 4a, 4b. Note that the determination device 10 relatively compares the change in the current value monitored by the current monitoring device 9 between the anode-side conductor elements 4a and 4b, and considers the comparison result, and each anode-side conductor element. The service life state of each anode-side conductor element 4a, 4b is determined based on the change in current value for each of 4a, 4b. Note that the determination result in the determination device 10 is output to the external DC power supply 7 and is used to cut off the current supply from the external DC power supply 7 to each of the anode-side conductor elements 4a and 4b.
[0035]
Next, the operation of the present embodiment having such a configuration will be described.
[0036]
In FIG. 1, a current flows between the anode-side conductor 4 (the anode forming member 5 and the electric catalyst 6) and the cathode-side conductor 8 via an external current power source 7. At this time, the potential between the anode-side conductor elements 4a, 4b and the cathode-side conductor 8 is within the range of 0.52 to 1.13V under the control of the automatic potential control section 7c of the external DC power source 7. And the current value is 0.3 to 3.0 A / m. ² Kept to a degree. Thus, oxygen can be generated without substantially generating chlorine gas in the seawater 15 via the electrocatalyst 6, and marine organisms can be attached to the tube plate 2a and the heat transfer tube 2b of the heat exchanger 2. Can prevent life.
[0037]
At this time, the current flowing through each anode-side conductor element 4a, 4b is monitored by the current monitoring device 9, and based on the accumulated current value or the change in the current value for the current flowing through each anode-side conductor element 4a, 4b. The service life state (soundness, performance degradation, etc.) of each anode-side conductor element 4a, 4b is determined.
[0038]
FIG. 2 is a diagram for explaining a specific determination method in the determination apparatus 10 shown in FIG.
[0039]
As shown in FIG. 2, in the determination device 10, first, output data from the current monitoring device 9 is captured, and an integrated current value of current flowing through each anode-side conductor element 4 a, 4 b or a change in the current value is acquired. (Step 101).
[0040]
Next, it is determined whether or not the integrated current value of the current flowing through each anode-side conductor element 4a, 4b exceeds a predetermined value (step 102), and it flows to each of the anode-side conductor elements 4a, 4b. If there is a current whose accumulated current value exceeds a predetermined value, it is determined that the electric catalysts 6a and 6b of the corresponding anode-side conductor elements 4a and 4b are consumed (step). 103).
[0041]
Here, since the electric catalyst elements 6a and 6b of the anode-side conductor elements 4a and 4b are dissolved and consumed in proportion to the integrated current value, the consumption amount with respect to the integrated current value is determined by the thickness (μm) of the electric catalyst. ) Can be used to calculate the wear life of each of the electrocatalytic elements 6a and 6b (see FIG. 3). Specifically, for example, when the electrocatalyst is a cobalt-based catalyst, the consumption amount with respect to the integrated current value can be predicted to be 520 mg / A · year, and the thickness of the electrocatalyst is 0.5 μm. It can be seen that the integrated current value is consumed when it exceeds 16.7 A · year. In this case, the current value is 1.0 A / m. ² If it is continuously energized at, it will be consumed in about 8 years. For this reason, it is possible to appropriately determine the consumption state of each of the electric catalysts 6a and 6b by setting the predetermined value in step 102 in consideration of such a consumption life.
[0042]
On the other hand, if it is determined in step 102 that the integrated current value of the current flowing through each anode-side conductor element 4a, 4b does not exceed a predetermined value, the process proceeds to step 104, where each anode-side conductor element is processed. It is examined whether or not the change in the value of the current flowing through 4a and 4b exceeds a predetermined range.
[0043]
In step 104, if there is a change in the value of the current flowing in each of the anode-side conductor elements 4a and 4b exceeding the predetermined range, the process proceeds to step 105. It is further determined whether or not the change in the current value flowing through the anode-side conductor elements 4a and 4b is with time. On the other hand, when the change in the current value flowing through each anode-side conductor element 4a, 4b is within a predetermined range, the process returns to step 101 and the above-described process is repeated.
[0044]
If it is determined in step 105 that the change in the current value flowing through the corresponding anode-side conductor elements 4a and 4b is a time-dependent change, the anode formation of the corresponding anode-side conductor elements 4a and 4b is performed. It is determined that the performance of the members 5a and 5b has deteriorated (step 106).
[0045]
Here, when the performance of each anode forming member 5a, 5b of each anode side conductor element 4a, 4b deteriorates, the potential between each anode side conductor element 4a, 4b and cathode side conductor 8 becomes a predetermined value. The current value required for maintaining decreases (see FIGS. 4A and 4B). For this reason, it is possible to appropriately determine the performance deterioration of each anode forming member 5a, 5b by monitoring the change in the current value flowing through each anode side conductor element 4a, 4b. Note that when the current value decreases due to the performance deterioration of the anode forming members 5a and 5b, the amount of oxygen generated from the electrocatalytic elements 6a and 6b also decreases in proportion to the current value. Naturally, it will fall. Specifically, the performance of each anode forming member 5a, 5b deteriorated when the current value decreased to about 1/5 to 1/10 of the initial value of the current value flowing through each anode side conductor element 4a, 4b. It is good to judge. At this time, the current value flowing through each anode-side conductor element 4a, 4b may fluctuate due to external factors such as seawater properties, such as red tide or inflow of contaminated seawater. The change of the measured current value is relatively compared between the anode-side conductor elements 4a and 4b, and based on the change of the current value of each anode-side conductor element 4a and 4b while considering the comparison result, The performance deterioration of the anode forming members 5a and 5b of the anode-side conductor elements 4a and 4b may be determined.
[0046]
On the other hand, if it is determined in step 105 that the change in the current value flowing through the corresponding anode-side conductor elements 4a and 4b is not time-dependent, the process proceeds to step 107 and the corresponding anode-side conductor element is processed. It is determined whether or not the value of the current flowing through 4a and 4b has increased abruptly (step 107).
[0047]
In step 107, when a sudden increase in the value of the current flowing through the corresponding anode-side conductor elements 4a and 4b is detected, an insulation failure may occur in the anode forming members 5a and 5b of the corresponding anode-side conductor elements 4a and 4b. (Step 108).
[0048]
Here, a sudden increase in the value of the current flowing through each anode-side conductor element 4a, 4b is caused when the insulating adhesive 3 is deteriorated or when a conductive foreign substance (such as a wire) drifting in the seawater 15 is transferred to the heat transfer tube 2b. Is a phenomenon of poor insulation caused when the anode forming member elements 5a and 5b and the heat transfer tube 2b (that is, the tube plate 2a) are electrically connected to each other, and the current flowing through the anode-side conductor elements 4a and 4b. This can be determined by monitoring the change in value. However, in the latter case, a conductive foreign substance (for example, a wire or the like) drifting in the seawater 15 is often temporarily caught at the inlet of the heat transfer tube 2b and then flows out.
[0049]
For this reason, when a sudden increase in the current value flowing through each anode-side conductor element 4a, 4b is detected, a change in the current value is detected after a lapse of a predetermined time, and each anode-side conductor element 4a, The presence or absence of insulation failure of each anode forming member element 5a, 5b of 4b may be determined again. Specifically, as shown in FIGS. 5A and 5B, it is determined that there is a possibility of insulation failure in each anode-side conductor element 4a, 4b due to an initial sudden increase in current value. After the current supply to each anode-side conductor element 4a, 4b is cut off (time A), the current supply to each anode-side conductor element 4a, 4b is waited for several seconds to several tens of seconds and time B is passed. To resume. At this time, if a sudden increase in the current value is not detected, it is determined that there is no possibility of insulation failure of each anode-side conductor element 4a, 4b (see FIG. 5A). On the other hand, when there is a sudden increase in the current value again, it is determined that there is a possibility of insulation failure of each anode-side conductor element 4a, 4b, and each anode-side conductor element 4a, 4b is detected at the timing of time C. The current supply to is cut off (see FIG. 5B).
[0050]
In addition, since the conductive foreign matter (for example, a wire) drifting in the seawater 15 often flows out when the flow direction of the seawater 15 is reversed, the value of the current flowing through each anode-side conductor element 4a, 4b is abrupt. When the increase is detected, the flow direction of the seawater 15 with respect to the heat exchanger 2 may be reversed, and the presence or absence of insulation failure of each anode-side conductor element 4a, 4b may be determined again.
[0051]
On the other hand, when a sudden decrease in the current value flowing through the corresponding anode-side conductor elements 4a and 4b is detected in step 107, it is due to a decrease in the area of the corresponding anode-side conductor elements 4a and 4b. It is determined that there is a possibility that the corresponding anode-side conductor elements 4a and 4b may be separated or partially damaged due to dents or wear (step 109).
[0052]
As described above, according to the present embodiment, the current flowing through the anode-side conductor 4 is monitored by the current monitoring device 9, and based on the integrated current value of the current flowing through the anode-side conductor 4 or the change in the current value, Since the determination device 10 determines the service life state (soundness and performance deterioration) of the conductor 4, the service life state of the anode-side conductor 4 is surely grasped, and marine organisms are attached or the steel is in contact with the sea water 15. Abnormal corrosion or the like of the manufactured member (water chamber 13 or the like) can be prevented in advance. Specifically, for example, by determining the consumption state of the electric catalyst 6 based on the integrated current value of the current flowing through the anode-side conductor 4, performance degradation when the electric catalyst 6 is used for a long time is obviated. It can be predicted, and adhesion of marine organisms due to performance deterioration of the electrocatalyst 6 can be prevented. Further, by determining the performance deterioration of the anode forming member 5 based on the change in the value of the current flowing through the anode-side conductor 4, it is possible to predict the performance deterioration when the anode forming member 5 is used for a long time. Moreover, adhesion of marine organisms due to performance deterioration of the anode forming member 5 can be prevented. Further, when the insulating adhesive 3 is deteriorated based on a change in the current value flowing through the anode-side conductor 4 (abrupt increase in the current value), or conductive foreign matters (such as a wire) drifting in the seawater 15 are generated. By reliably grasping the presence or absence of insulation failure that occurs when caught at the inlet of the heat transfer tube 2b or the like, abnormal corrosion of the steel member (water chamber 13 or the like) that contacts the seawater 15 can be prevented in advance. Furthermore, the anode-side conductor 4 is reliably determined by determining whether the anode-side conductor 4 is peeled off or partially damaged based on a change in the current value flowing through the anode-side conductor 4 (abrupt decrease in the current value). Can be effectively prevented from flowing out and adversely affecting the heat exchanger 2, the water chamber 13, and the like.
[0053]
Further, according to the present embodiment, the anode-side conductor 4 is divided into a plurality of anode-side conductor elements 4 a and 4 b that are insulated from each other, and flows to the anode-side conductor elements 4 a and 4 b by the current monitoring device 9. Since each of the currents is monitored, even when the anode-side conductor 4 (the anode forming member 5 and the electric catalyst 6) has a large area, the performance deterioration of the large area anode forming member 5 and the electric catalyst 6 It is easy to determine at which part the deterioration of the insulating adhesive 3 occurs, and at which part the conductive foreign matter is caught at the inlet of the heat transfer tube 2b. Maintenance management such as repair and renewal can be performed easily and inexpensively.
[0054]
Furthermore, according to the present embodiment, the change in the current value is relatively compared between each anode-side conductor element 4a, 4b, and each anode-side conductor element 4a, 4b is taken into account while considering the comparison result. Since the durability of each of the anode-side conductor elements 4a and 4b is determined based on the change in the current value, the influence of current fluctuation due to external factors such as seawater properties is excluded, and the anode-side conductor 4 The service life state can be accurately determined.
[0055]
Furthermore, according to the present embodiment, when a sudden increase in the current value flowing through the anode-side conductor 4 is detected, a change in the current value is detected after a lapse of a predetermined time, and the anode-side conductor is detected. 4, the presence or absence of insulation failure of the anode forming member 5 is determined again, so that the malfunction of insulation failure is prevented when a conductive foreign matter drifting in the seawater 15 is temporarily caught in the inlet of the heat transfer tube 2b and then flows out. be able to. At this time, the conductive foreign matter floating in the seawater 15 is effectively removed by reversing the flow direction of the seawater 15 before re-determining whether or not the anode forming member 5 of the anode-side conductor 4 has poor insulation. Can be drained.
[0056]
In addition, according to this Embodiment, since the anode formation member 5 beforehand coat | covered with the electrocatalyst 6 is adhere | attached on the tube sheet 2a through the insulating adhesive agent 3 at normal temperature, the electrocatalyst 6 It is no longer necessary to perform the electrical resistance heat treatment at 350 to 450 ° for several hours on the tube plate 2a, which is necessary for the catalytic activity of the tube, and the tube plate 2a may be damaged by the generated heat or thermal stress. Sex can be effectively avoided.
[0057]
In the above-described embodiment, the anode-side conductor 4 is provided on the tube plate 2a of the heat exchanger 2 via the insulating adhesive 3. However, as shown in FIG. An insulating sheet 18 may be arranged between the anode 3 and the anode-side conductor 4. Thereby, the electrical insulation between the tube sheet 2a and the anode side conductor 4 can be firmly realized. In this case, the adhesive for bonding between the tube sheet 2a and the insulating sheet 18 and between the insulating sheet 18 and the anode-side conductor 4 does not necessarily have insulating properties. .
[0058]
Moreover, in embodiment mentioned above, although the anode side conductor 4 is provided on the tube sheet 2a of the heat exchanger 2, it is not restricted to this, On the insulator previously provided in the seawater contact structure The anode side conductor 4 may be provided. Specifically, for example, as shown in FIG. 7, the anode-side conductor 4 is provided on the rubber lining (insulator) 11 provided on the surface of the water chamber 13 which is a seawater contact structure via an adhesive 16. be able to. Moreover, as shown in FIG. 8, the anode side conductor 4 can be provided through the adhesive agent 16 on the concrete intake channel 14 which is a seawater contact structure. In the case shown in FIG. 8, reinforcing reinforcing bars (a part of which is in contact with the seawater 15) of the cooling water intake concrete concrete intake channel 14 act as the conductor 8. Moreover, in any case shown in FIG. 7 and FIG. 8, since the rubber lining 11 and the concrete intake channel 14 have insulating properties, the adhesive 16 itself does not need to have insulating properties. The anode-side conductor 4 is not limited to the rubber lining 11 and the concrete intake channel 14 shown in FIGS. 7 and 8 but also on various insulators such as a resin material provided in the seawater contact structure. It is possible to provide.
[0059]
【The invention's effect】
As described above, according to the present invention, the current flowing through the anode-side conductor is monitored, and based on the accumulated current value of the current flowing through the anode-side conductor or the change in the current value, Therefore, it is possible to reliably grasp the service life of the anode-side conductor and prevent marine organisms from attaching due to the performance deterioration of the anode-side conductor. In addition, abnormal corrosion of steel members in contact with seawater caused by poor insulation that occurs when the insulation part deteriorates or when conductive foreign matter floating in seawater gets caught in the seawater contact structure, etc. Can be prevented.
[0060]
Further, the anode-side conductor has a large area by dividing the anode-side conductor into a plurality of anode-side conductor elements insulated from each other and monitoring the current flowing through each anode-side conductor element. Even in such a case, it is possible to easily identify in which part the performance deterioration of the anode-side conductor having the large area is occurring, and maintenance management such as repair and update can be performed easily and inexpensively.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an embodiment of an antifouling device for a seawater contact structure according to the present invention.
FIG. 2 is a flowchart for explaining a performance deterioration monitoring method for antifouling purchase of the seawater contact structure shown in FIG. 1;
FIG. 3 is a diagram for explaining a method of determining a consumption state of an electrocatalyst in the antifouling device for a seawater contact structure shown in FIG. 1;
4 is a diagram for explaining a method of determining performance deterioration of an anode forming member in the seawater contact structure antifouling apparatus shown in FIG. 1; FIG.
FIG. 5 is a diagram for explaining how to determine an anode forming member when a sudden increase in current value is detected in the antifouling device for seawater contact structure shown in FIG. 1;
6 is a schematic view showing a modification of the antifouling device for the seawater contact structure shown in FIG. 1. FIG.
FIG. 7 is a schematic view showing another modification of the antifouling device for the seawater contact structure shown in FIG. 1;
8 is a schematic view showing still another modification of the antifouling device for seawater contact structure shown in FIG.
[Explanation of symbols]
1 Seawater contact structure antifouling device
2 Heat exchanger
2a Tube sheet
2b Heat transfer tube
3 Insulating adhesive (insulating part)
4 Anode-side conductor
5 Anode forming member
6 Electrocatalyst
7 External DC power supply (external power supply)
7a positive electrode
7b Negative electrode
7r reference pole
7c Automatic potential controller
8 Cathode side conductor
9 Current monitoring device
10 Judgment device
11 Rubber lining (insulator)
12 Reference electrode
13 Water chamber
14 Concrete intake channel (insulator)
15 Seawater
16 Adhesive
17 Insulating adhesive
18 Insulation sheet (insulating part)

Claims

In the antifouling device for a seawater contact structure that suppresses the growth of marine organisms on the seawater contact structure,
An anode-side conductor provided on the seawater-side surface of the seawater contact structure via an insulating portion, the anode-side conductor having an electrochemically active electrocatalyst;
A cathode-side conductor provided in sea water;
An external power source having a positive electrode connected to the anode-side conductor and a negative electrode connected to the cathode-side conductor, wherein oxygen is generated in seawater via the electric catalyst of the anode-side conductor. An external power source for controlling the potential between the positive electrode and the negative electrode;
A current monitoring device for monitoring a current flowing through the anode-side conductor;
An antifouling device for a seawater contact structure, comprising: a determination device that determines a durability state of the anode-side conductor based on a monitoring result by the current monitoring device.

2. The seawater according to claim 1, wherein the anode-side conductor includes a plurality of anode-side conductor elements insulated from each other, and the current monitoring device monitors a current flowing through each anode-side conductor element. Antifouling device for contact structures.

2. The antifouling device for seawater contact structure according to claim 1, wherein the determination device determines a durability state of the anode-side conductor based on an integrated current value monitored by the current monitoring device.

2. The antifouling device for seawater contact structure according to claim 1, wherein the determination device determines a durability state of the anode-side conductor based on a change in a current value monitored by the current monitoring device.

The determination device relatively compares the change in the current value monitored by the current monitoring device between the anode-side conductor elements, and considers the comparison result, and the current value for each anode-side conductor element. The antifouling device for a seawater contact structure according to claim 2, wherein the service life of each anode-side conductor element is determined based on the change of the seawater contact structure.

2. The antifouling device for seawater contact structure according to claim 1, wherein the insulating part is an insulating adhesive for adhering the seawater side surface of the seawater contact structure and the anode conductor to each other. .

2. The antifouling device for seawater contact structure according to claim 1, wherein the insulating portion is an insulating sheet disposed between a seawater side surface of the seawater contact structure and the anode conductor.

2. The antifouling device for a seawater contact structure according to claim 1, wherein the insulating portion is an insulator coated on a seawater side surface of the seawater contact structure.

The electrocatalyst of the anode-side conductor is a single body, a mixed crystal body, or a composite body including at least one of a platinum-based metal, a platinum-based metal oxide, and an oxide of cobalt or manganese. The antifouling device for seawater contact structure according to claim 1.

In the performance deterioration monitoring method of the antifouling device for seawater contact structures that suppresses the growth of marine organisms on the seawater contact structures,
By passing a current between an anode-side conductor provided on the seawater-side surface of the seawater contact structure via an insulating portion and a cathode-side conductor provided in seawater, the anode-side conductor Generating oxygen in seawater via an electrochemically active electrocatalyst having,
Monitoring the current flowing through the anode-side conductor during the oxygen generation step;
And a step of determining a service life state of the anode-side conductor based on a monitoring result of the monitoring step.

11. The performance according to claim 10, wherein the anode-side conductor includes a plurality of anode-side conductor elements insulated from each other, and the current flowing through each anode-side conductor element is monitored in the monitoring step. Deterioration monitoring method.

The performance deterioration monitoring method according to claim 10, wherein in the determination step, a durability state of the anode-side conductor is determined based on an integrated current value monitored in the monitoring step.

The performance deterioration monitoring method according to claim 10, wherein in the determination step, the durability state of the anode-side conductor is determined based on a change in the current value monitored in the monitoring step.

The performance deterioration according to claim 13, wherein in the determination step, it is determined that there is a possibility of insulation failure in the anode-side conductor when a rapid increase in current value is monitored in the monitoring step. Monitoring method.

The determination step, after determining that the anode-side conductor has a possibility of insulation failure, waits for a predetermined time to determine again whether or not the anode-side conductor has insulation failure. Item 15. The performance deterioration monitoring method according to Item 14.

In the determination step, after determining that there is a possibility of poor insulation in the anode-side conductor, the presence or absence of insulation failure in the anode-side conductor is determined after reversing the flow direction of seawater with respect to the seawater contact structure. 15. The performance deterioration monitoring method according to claim 14, wherein the determination is made again.

14. The determination step, when a sudden decrease in current value is detected in the monitoring step, it is determined that the anode-side conductor may be peeled off or partially damaged. Performance degradation monitoring method.

In the determination step, the change in the current value monitored in the monitoring step is relatively compared between the anode-side conductor elements, and the current value for each anode-side conductor element while considering the comparison result The performance deterioration monitoring method according to claim 11, wherein a service life state of each anode-side conductor element is determined based on a change in the value.