JP2004351312A

JP2004351312A - Method and apparatus for regenerating activated carbon and air purifying system with the activated carbon incorporated

Info

Publication number: JP2004351312A
Application number: JP2003151794A
Authority: JP
Inventors: Kaiho To; 懐鵬湯; Kazuya Tajima; 和也田島; Yoichi Kato; 陽一加藤; Fumio Kimura; 文夫木村
Original assignee: Shinryo Corp
Current assignee: Shinryo Corp
Priority date: 2003-05-29
Filing date: 2003-05-29
Publication date: 2004-12-16
Anticipated expiration: 2023-05-29
Also published as: JP4234496B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for regenerating activated carbon, by which the activated carbon on that a harmful gas is adsorbed fully and through that the harmful gas breaks can be regenerated efficiently in safe without wasting the activated carbon and to provide an air purifying system in which the activated carbon is incorporated and regenerated. <P>SOLUTION: This method for regenerating the activated carbon comprises the first step to regenerate the activated carbon by jetting superheated steam of 150-250°C toward the activated carbon when a low-boiling point substance is desorbed and the second step to regenerate the activated carbon by jetting superheated steam of 300-350°C toward the activated carbon when a high-boiling point substance is desorbed. This apparatus for regenerating the activated carbon is provided with a superheated steam supplying part, an adsorbent-packed part and an exhaust gas treating part. The superheated steam supplied from the superheated steam supplying part is jetted toward an activated carbon filter in the adsorbent-packed part. A temperature sensor is arranged on the downstream side of the adsorbent-packed part. A unit for decomposing the gas desorbed and separated from the activated carbon is arranged in the exhaust gas treating part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
室内空気汚染については、従来から粉塵、微生物や無機系ガス状汚染物質（ＮＯｘ，ＳＯｘ，オゾン）などが挙げられている。近年、有機系化学物質による汚染問題が新たに浮上して社会問題となっている。特に新築住宅や教室のような室内では、揮発性有機化合物（ＶｏｌｉｔｉｌｅＯｒｇａｎｉｃＣｏｍｐｏｕｎｄｓ、以下ＶＯＣと略す）やホルムアルデヒド（以下ＨＣＨＯと略す）の室内濃度が異常に高く、それが原因で化学物質過敏症やシックビルディング（病気発症建物），シックスクール症候群に発展してしまうケースも多く見られ、現状調査や対策などについて多くの研究報告がなされている。
【０００２】
この問題を解決するために、厚生労働省はＶＯＣやＨＣＨＯなど１３物質に関して室内濃度の指針値を発表し、国土交通省は住宅の性能表示制度において、化学物質室内濃度の一部表示を平成１３年８月に追加し、また文部科学省では、学校施設に関する「学校環境衛生の基準」に化学物質の基準値を設定し、新築や改築を行った時の引き渡し条件に化学物質測定や濃度超過時の改善対策を取り入れ、２００２年４月から実施している。
さらに建築基準法及び建築物における衛生的環境確保に関する法律は２００２年に改正され、ＨＣＨＯなどの室内空気化学物質汚染が法的に規制されるようになった。
本発明は、上記の有害ガスの濃度を低減するために空調や換気システムにおいて使用される活性炭フィルターの再生方法と再生装置、及びそれを組み込んだ空気浄化システムに係るものである。
【０００３】
【従来の技術】
ライフタイムが終了して破過した吸着剤を再生する従来の方法としては、
Ａ温風再生（特許第３３９５０７７号）
Ｂジュール熱再生
Ｃ大気圧下での噴射蒸気による再生（特開平７−２７５６３６）
Ｄ活性炭再生プラントでの高温加圧過熱蒸気再生、などが知られている。
【０００４】
これらの方法の問題点として、
（１）温風再生（通常は１５０〜２００℃）については、トルエンのような低沸点物質（沸点１１０℃以下）には有効だが、室内空気中には脂肪族飽和炭化水素のドデカン，ヘキサデカン，フタル酸エステル類などの高沸点物質も大量に存在し、そのような吸着物質には再生効率が低い。そのため複数回再生後、活性炭の吸着性能が低下する。
（２）温風再生やジュール熱再生の場合、空気中に酸素の存在する雰囲気で、可燃物である活性炭に熱を直接加えることは、活性炭の酸化による消耗が大きいほか、安全上も問題があり、無人自動では運転できない。大型ビル施設の場合、空調システムが数十、数百もあり、人が監視しながら活性炭の再生を行うことは実用上困難である。
【０００５】
（３）大気圧飽和蒸気再生の場合、処理対象はＮＯｘやＳＯｘを吸着した活性炭であり、再生温度が低いことや、再生後の室内からの排気による乾燥工程におけるＶＯＣの再吸着によって、効果的な再生システムとならない。
（４）活性炭再生プラントでの高温過熱蒸気再生は加圧状態での再生であり、空調系などに組み込むには適さない。また、１回の再生につき、活性炭が２〜９％減量する。また、耐圧や耐熱（再生温度８００〜１０００℃）等の問題で空調システムには応用できない。再生による活性炭のロスが１回あたり２〜９％と大きく、コストもかかる。
【０００６】
（５）再生時の排気による大気汚染問題がある。
（６）従来の空調用活性炭フィルターは、再生頻度を少なくするために、厚さが大きくなり、ＳＶ値｛通過風量（ｍ^３／ｈ）／吸着剤充填部容積（ｍ^３）｝が３万／ｈ前後と低くても圧力損失が４００Ｐａ前後と大きい。
（７）再生効率が低い。特に複数回再生後、吸着剤の吸着性能が低下する。
（８）従来の再生方法では、再生時の排気に対して分解処理を行っておらず、高濃度の再生排気ガスによる大気汚染問題があり、結果的に有害な化学物質のトータル的な低減ではなく、室内から室外（大気）へ排出するだけである。
【０００７】
【発明が解決しようとする課題】
本発明の主たる目的は、有害ガスを吸着し破過した活性炭を、安全に効率良くかつ活性炭を消耗させずに再生させる方法と装置を提供することにある。
本発明の他の目的は、有害ガスを吸着し破過した活性炭を空気浄化装置内に組み込んだまま再生させるような空気浄化システムを提供することにある。
本発明のさらに他の目的は、再生時の排気中の脱着ガスを分解処理し、大気を汚染しないようにすることにある。
【０００８】
【課題を解決するための手段】
前述した課題を達成するため、本発明はその第１の態様において、有害ガスを吸着した活性炭を再生する方法であって、低沸点物質に対して１５０〜２５０℃の過熱蒸気を噴射して再生する第１段階と、高沸点物質に対して必要に応じて３００〜３５０℃の過熱蒸気を噴射して再生する第２段階とを組み合わせて行う活性炭再生方法を提供する。
【０００９】
【作用】
かかる再生方法によれば、低沸点物質（沸点１１０℃以下）に対する１５０〜２５０℃の過熱蒸気による通常再生（第１段階）と、高沸点物質（沸点１１０℃を超える）に対する３００〜３５０℃の過熱蒸気による完全再生（第２段階）の二つの再生条件を組み合わせて、通常再生を数回行った後に完全再生を１回行うことにより、破過した活性炭を再生させ、かつ吸着性能の低下を防ぐことができる。
【００１０】
本発明はその第２の態様において、有害ガスを吸着した活性炭を再生する装置であって、活性炭に含まれる有害物質をその沸点以上に加熱する過熱蒸気供給部と、大気圧の状態に保持され活性炭フィルターを装着可能な吸着剤設置部と、排気処理部とを備え、前記過熱蒸気供給部は蒸気発生器と過熱用ヒーターとを包含し、過熱蒸気を前記吸着剤設置部内の活性炭フィルターに供給して活性炭に噴射するようになっており、前記吸着剤設置部の下流側には温度センサーが設けられ、前記排気処理部には活性炭から分離した脱着ガスを分解するユニットが設けられており、過熱蒸気を活性炭に噴射して活性炭を再生すると共に脱着ガスを分解して大気中へと排出するようになっている活性炭再生装置を提供する。
【００１１】
かかる装置では、活性炭の再生には大気圧の過熱蒸気を使用する。可燃物である活性炭に過熱蒸気を導入し充満させることで、燃焼に必要な酸素を遮断でき、活性炭の消耗がほとんどなく、安全性も確保される。過熱蒸気による再生の圧力が大気圧とほぼ同じなので、装置に耐圧性が不要である。
過熱蒸気を用いるので、飽和蒸気再生の場合の吸着剤への水分の吸着がなく、再生後の吸着剤の乾燥工程は不要であり、乾燥工程における吸着剤の汚染物質再吸着がない。
【００１２】
温風再生の空気分子（Ｎ_２，Ｏ_２）よりも過熱蒸気の水分子（Ｈ_２Ｏ）の方が吸着物質を脱着させるエネルギが大きく、過熱蒸気による再生では同温度の温風再生よりも高い再生効率が得られる。
再生後の過熱蒸気排気を直接脱着ガス分解ユニットに導入し、排気中の化学物質を分解処理する。分解処理によって９５％以上の有害ガス（ＶＯＣ）を浄化した後に大気に排出する。
【００１３】
さらに、本発明の装置によれば次のような作用効果が得られる。
（１）過熱蒸気の水熱反応及び、低沸点・高沸点の２段階再生で再生効率が良く、吸着剤が半永久的に使える
（２）大気圧下での過熱蒸気による再生なので、耐圧構造の必要がなく、空調系においても適用できる
（３）再生時に過熱蒸気を装置内に充満することで酸素供給を遮断するので、活性炭の消耗による減量がほとんどなく、また安全に再生ができる
（４）再生時の排気中の脱着ガスを分解処理した後に大気中に放出するため、大気をほとんど汚染しない
（５）再生機能付き空気浄化装置として空調系に組み込んだ場合、高ＳＶ値で運転できるので、吸着剤使用量が従来の１／３〜１／１５にでき、省資源、省スペースになる
（６）再生機能付き空気浄化装置として空調系に組み込んだ場合、低圧力損失で省エネルギーである。ブースタファンの追加が必要なく、ＡＨＵの機外静圧で対応できる。
【００１４】
本発明はその第３の態様として、有害ガスを吸着した活性炭を再生する機構を有する空気浄化システムであって、空調対象室から空気を誘引するファン又はブロアと、除塵フィルターを包含するフィルターユニットと、活性炭再生機構を包含する空気浄化部分と、空調機と、それらを接続する配管とを備え、前記活性炭再生機構は、活性炭に含まれる有害物質をその沸点以上に加熱する過熱蒸気供給部と、大気圧の状態に保持され活性炭フィルターを装着可能な吸着剤設置部と、排気処理部とを包含しており、前記過熱蒸気供給部は蒸気発生器と過熱用ヒーターとを有し、過熱蒸気を前記吸着剤設置部内の活性炭フィルターに供給して活性炭に噴射するようになっており、前記吸着剤設置部の下流側には温度センサーが設けられ、前記排気処理部には活性炭から分離した脱着ガスを分解するユニットが設けられており、過熱蒸気を活性炭に噴射して活性炭を再生すると共に脱着ガスを分解して大気中へと排出するようになっている空気浄化システムを提供する。
【００１５】
かかる空気浄化システムによれば、空気浄化装置（活性炭フィルター）と組み合わされた再生機能付きＶＯＣ除去装置を備えた空調システムが構築される。再生用蒸気は過熱状態だか、大気圧なので耐圧容器などが不要で、空調系にも応用できる。
【００１６】
従来の空気浄化システムに組み込まれたＶＯＣ除去用活性炭フィルターは活性炭のライフタイムが短いので、破過したフィルターの頻繁な交換を避けるためにＳＶ値が１〜５万／ｈと低く設定されている。その場合は活性炭の使用量が多いのでフィルターの圧力損失も４００Ｐａ（ＳＶ値３万／ｈの場合）と大きい。
今回の活性炭空気浄化システムでは、活性炭フィルターが破過しても安全で有効な再生ができるようにしたので、１５万／ｈのＳＶ値を可能にし、使用吸着剤量は従来の１／１５〜１／３となり、省スペース、省資源、省コストになる。また、活性炭の使用量を減らしたことでフィルターの低圧力損失を実現し、ブースタファンを増設せずに空調機の機外静圧でも運転できるようになるので、省エネルギ、省コストになる。
【００１７】
【発明の実施の形態】
図１は本発明の好適な実施態様による活性炭再生装置を表している。この再生装置を温度条件を変えて繰り返し使用することで、活性炭に第１段階の通常再生と第２段階の完全再生とを実施することができる。
図１の再生装置１０は、有害ガスの沸点以上に加熱するための過熱蒸気供給部１２、大気圧の状態に保持された吸着剤設置部１４、及び排気処理部１６から構成され、それぞれは配管で接続されている。過熱蒸気供給部１２は蒸気発生器１８と過熱用ヒーター２０で構成され、配管で吸着剤設置部１４と接続されている。吸着剤設置部１４には、有害ガスを吸着し破過した活性炭フィルター２２が装着され、その下流側に温度センサー２４が設けられている。排気処理部１６は、開閉ダンパーＶＤ１、開閉ダンパーＶＤ２、脱着ガス分解ユニット２６、空気取入口２７及びブロア２８で構成され、配管で接続されている。
【００１８】
図１の再生装置１０では、過熱蒸気供給部１２から大気圧の状態に保持された吸着剤設置部１４に過熱蒸気を供給し、有害ガスを吸着し破過した活性炭フィルター２２を再生して、排気処理部１６の脱着ガス分解ユニット２６で排気中の有害ガス（ＶＯＣ）を浄化した後、大気に排出する。温度センサー２４は吸着剤設置部１４の温度を検出し、再生温度が設定温度に保持されるように、過熱用ヒーター２０の出力を調節する。
【００１９】
脱着ガス分解ユニット２６による分解方法は、触媒による分解方法とプラズマ式分解方法とがあり、どちらの方法も採用できる。触媒による分解方法に使用される触媒は、貴金属の白金，パラジウム，卑金属のコバルト，クロム，マンガン，酸化バナジウム，二酸化チタン等を使用できる。再生後の過熱蒸気排気を直接脱着ガス分解ユニットに導入し、再生排気の余熱も有効に利用して排気中の化学物質を分解処理できる。特に白金を触媒として脱着ガス分解ユニットに使用する場合は、排気処理部１６の開閉ダンパーＶＤ１と脱着ガス分解ユニット２６の間に補助ヒーター（図示せず）が、触媒ユニットの反応速度を維持するために設けられる。開閉ダンパーＶＤ１及びＶＤ２の操作によって、脱着ガス分解ユニット２６からの排気と空気取入口２７から吸入される空気の量を調節し、ブロア２８の入口温度をブロアの耐熱温度以下に保つとともに、活性炭フィルター２２の圧力損失に応じて適正な再生蒸気量を確保する。
【００２０】
図２は、本発明の他の実施例による活性炭再生装置を表しており、この再生装置３０では、大気圧の状態に保持された吸着剤設置部３４に循環ライン３２を設けた点に特徴を有する。循環ライン３２は、配管３６、ブロア３８、過熱ヒーター４０、温度センサー４２を包含し、吸着剤設置部３４に設けられた第１の温度センサー２４の下流側と、有害ガスを吸着し破過した活性炭フィルター２２の上流側とにそれぞれ配管３６を介して接続されている。
この循環ライン３２は、排気の一部をブロア３８により循環させ、過熱ヒーター４０により再過熱した後、過熱蒸気供給部１２から供給される過熱蒸気と混合し、吸着剤設置部３４に設けられた活性炭フィルター２２の再生に利用する方式の例である。この実施例は、図１の例に比べて過熱に要するエネルギを少なくできるという利点がある。
【００２１】
図３は、本発明のさらに他の実施例による活性炭再生装置を表しており、この再生装置５０では、大気圧の状態に保持された吸着剤設置部５４にパージライン５２を設けた点に特徴を有する。パージライン５２は、空気入口５５、配管５６と開閉ダンパーＭＶ１とで構成され、吸着剤設置部５４において有害ガスを吸着し破過した活性炭フィルター２２の上流側に接続されている。
再生過程終了後、ブロア２８を運転した状態で開閉ダンパーＭＶ１を開くと、パージ用空気が流入し活性炭を速やかに冷却できる。図２の例の場合には、パージ空気取入口５５を循環ライン３２の途中に設けることもできる。
【００２２】
図４は、上述した活性炭再生装置を組み込んだ空気浄化システムの実施例を表している。この空気浄化システム６０は、空調対象室６２、各機器を接続する配管６３、空調対象室６２からＲＡ（戻り空気）を取り出すための取出口６４、排気ファン６６、除塵フィルター６９を内蔵し外気取入口６８から外気を導入するフィルターユニット７０、モーター７３で回転する回転式活性炭フィルター７４を包含する空気浄化装置７２、空調機（ＡＨＵ）７６及び空調対象室６２へとＳＡ（供給空気）を供給する給気口７８を包含している。
【００２３】
回転式活性炭フィルター７４は、前述した特開平７−２７５６３６に記載したようなタイプで、フィルター部分を回転させながら再生させる機能を有している。通常の空調時は、冷却空気取入口７５の開閉ダンパーＭＶ１が閉じている。再生時には、蒸気発生器１８と過熱用ヒーター２０からの再生用の過熱蒸気が導入されるようになっており、同時に冷却空気取入口７５から開閉ダンパーＭＶ１を介して冷却空気が導入される。
【００２４】
空調対象室６２では、通常の空調運転時は、ＲＡ取出口６４から室内空気を取り出し、その一部の空気を排気ファン６６で排気する。残りの空気と外気取入口６８から取り入れた外気を、フィルターユニット７０内に設置された除塵フィルター６９で除塵し、空気浄化装置７２内に設置された回転式活性炭フィルター７４で有害ガスを吸着除去し、清浄な空気を空調機７６に送る。空調機７６により所望の空気状態（温度・湿度）にしてＳＡ給気口７８から空調対象室６２へ給気する。
【００２５】
活性炭フィルター７４は吸着部→脱着部→冷却部の順に回転する。この際、ＶＯＣ濃度モニター８０で回転式活性炭フィルター７４の上流側と下流側から空気をサンプリングし、回転式活性炭フィルターの再生が必要か否かを判断する。活性炭フィルター７４の再生運転は、通常の空調運転時又は空調停止時に行う。再生運転は、脱着部・冷却部・吸着部と順に活性炭フィルター７４が回転して行われる。間欠空調の場合には、空調運転が停止しているときに再生運転を行ってもよい。
なおこの実施例では回転式活性炭フィルター７４を用いているが、静止型活性炭フィルターを用いることもできる。
【００２６】
図５は、本発明による大気圧過熱蒸気再生と温風再生との効果比較を表している。本発明による再生方法の方が従来の温風再生よりもはるかに再生効率が高いことが立証された。
【００２７】
表１は、同じハニカム成形活性炭を使用して、本発明と従来の活性炭フィルターとを比較した結果を表している。
【表１】

【００２８】
表２は、本発明の再生方法による活性炭ロス率を表している。ここで、活性炭ロス率＝（新品活性炭重量−再生後活性炭重量）／（新品活性炭重量）×１００と定義する。
【表２】

【００２９】
【発明の効果】
以上詳細に説明した如く、本発明の活性炭再生方法・再生装置によれば、長期間にわたり活性炭の減量が少なく、安全で再生効率の高い再生運転ができ、かつ大気汚染の問題も解決される。それを備えた空気浄化システムでは活性炭フィルターが半永久的に使用でき、省資源とともに、活性炭フィルターの圧力損失を大幅に削減でき、省エネルギ効果が極めて大きいなど、その技術的効果には極めて顕著なものがある。
【図面の簡単な説明】
【図１】本発明による活性炭再生装置の概略回路図。
【図２】他の実施例による活性炭再生装置の概略回路図。
【図３】他の実施例による活性炭再生装置の概略回路図。
【図４】活性炭再生装置を含む空気浄化システムの概略回路図。
【図５】大気圧過熱蒸気再生と温風再生との効果を比較したグラフ。
【符号の説明】
１０，３０，５０活性炭再生装置
１２過熱蒸気供給部
１４吸着剤設置部
１６排気処理部
１８蒸気発生器
２０過熱用ヒーター
２２，７４活性炭フィルター
２４温度センサー
２６脱着ガス分解ユニット
２８ブロア
６０空気浄化システム
６２空調対象室
６３配管
６６排気ファン
６９除塵フィルター
７０フィルターユニット
７２空気浄化装置
７６空調機[0001]
TECHNICAL FIELD OF THE INVENTION
As for indoor air pollution, dust, microorganisms, inorganic gaseous pollutants (NOx, SOx, ozone), and the like have been conventionally mentioned. In recent years, the problem of contamination by organic chemicals has newly emerged and has become a social problem. In particular, indoors such as new houses and classrooms have abnormally high indoor concentrations of volatile organic compounds (hereinafter abbreviated as VOC) and formaldehyde (hereinafter abbreviated as HCHO), which may cause chemical sensitivity and In many cases, it has developed into a sick building (sick building) and sick school syndrome, and many research reports have been made on the current status surveys and countermeasures.
[0002]
In order to solve this problem, the Ministry of Health, Labor and Welfare has announced guidelines for indoor concentrations of 13 substances such as VOCs and HCHOs, and the Ministry of Land, Infrastructure, Transport and Tourism has stated in the House Performance Labeling System that some of the indoor concentrations of chemical substances have been indicated in 2001. Added in August, and the Ministry of Education, Culture, Sports, Science and Technology has set standard values for chemical substances in the “School Environmental Sanitation Standards” for school facilities, The measures have been implemented since April 2002.
In addition, the Building Standards Law and the Law Concerning Sanitary Environment in Buildings were revised in 2002, and legal regulations on indoor air chemical contamination such as HCHO have been made.
The present invention relates to a method and apparatus for regenerating an activated carbon filter used in an air conditioning or ventilation system to reduce the concentration of the harmful gas, and an air purification system incorporating the same.
[0003]
[Prior art]
Conventional methods for regenerating a broken-through adsorbent at the end of its lifetime include:
A Hot air regeneration (Patent No. 3395077)
B Joule heat regeneration C Regeneration by jet steam under atmospheric pressure (JP-A-7-275636)
D. High-temperature pressurized superheated steam regeneration in an activated carbon regeneration plant is known.
[0004]
The problem with these methods is that
(1) For hot air regeneration (usually 150 to 200 ° C.), it is effective for low-boiling substances such as toluene (boiling point 110 ° C. or less), but in indoor air, aliphatic saturated hydrocarbons such as dodecane, hexadecane, High-boiling substances such as phthalates also exist in large amounts, and such adsorbed substances have low regeneration efficiency. Therefore, after a plurality of regenerations, the adsorption performance of activated carbon decreases.
(2) In the case of hot air regeneration or Joule heat regeneration, applying heat directly to combustible activated carbon in an atmosphere where oxygen is present in the air causes a great deal of consumption due to oxidation of the activated carbon and also poses a safety problem. Yes, unmanned automatic driving is not possible. In the case of large building facilities, there are tens or hundreds of air conditioning systems, and it is practically difficult for a person to monitor and regenerate activated carbon while monitoring.
[0005]
(3) In the case of the atmospheric pressure saturated steam regeneration, the object to be treated is activated carbon to which NOx and SOx are adsorbed, which is effective due to the low regeneration temperature and the re-adsorption of VOCs in the drying step by exhaustion from the room after the regeneration. It does not become a simple playback system.
(4) The high-temperature superheated steam regeneration in the activated carbon regeneration plant is a regeneration in a pressurized state, and is not suitable for being incorporated in an air conditioning system or the like. In addition, activated carbon is reduced by 2 to 9% per regeneration. Further, it cannot be applied to an air conditioning system due to problems such as pressure resistance and heat resistance (regeneration temperature of 800 to 1000 ° C.). Loss of activated carbon due to regeneration is as large as 2 to 9% per operation, and costs are high.
[0006]
(5) There is a problem of air pollution due to exhaust during regeneration.
(6) In order to reduce the frequency of regeneration, the conventional activated carbon filter for air conditioning has a large thickness, and the SV value {the amount of passing air (m ³ / h) / the volume of the adsorbent filled portion (m ³ )} is 30,000. Even though the pressure loss is as low as about / h, the pressure loss is as large as about 400 Pa.
(7) The regeneration efficiency is low. In particular, after a plurality of regenerations, the adsorption performance of the adsorbent decreases.
(8) In the conventional regeneration method, the exhaust gas at the time of regeneration is not decomposed, and there is a problem of air pollution due to the high concentration of the exhaust gas. As a result, the total reduction of harmful chemical substances cannot be achieved. Instead, it only discharges from the room to the outside (atmosphere).
[0007]
[Problems to be solved by the invention]
A main object of the present invention is to provide a method and an apparatus for safely and efficiently regenerating activated carbon that has absorbed and passed through a harmful gas without depleting the activated carbon.
Another object of the present invention is to provide an air purification system that regenerates activated carbon that has absorbed and passed through a harmful gas while being incorporated in an air purification device.
Still another object of the present invention is to decompose desorbed gas in exhaust gas during regeneration so as not to pollute the atmosphere.
[0008]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention, in its first aspect, is a method for regenerating activated carbon adsorbing a harmful gas, the method comprising injecting superheated steam at 150 to 250 ° C to a low-boiling substance to regenerate the activated carbon. An activated carbon regeneration method is provided in which the first step of regenerating activated carbon is combined with the second step of regenerating by injecting superheated steam at 300 to 350 ° C. as needed for a high boiling substance.
[0009]
[Action]
According to such a regeneration method, normal regeneration (first stage) using superheated steam of 150 to 250 ° C for low boiling substances (boiling point of 110 ° C or lower) and 300 to 350 ° C for high boiling substances (boiling point of more than 110 ° C) are performed. By combining the two regeneration conditions of complete regeneration (second stage) with superheated steam, performing normal regeneration several times and then performing complete regeneration once, the activated carbon that has broken through can be regenerated and the adsorption performance can be reduced. Can be prevented.
[0010]
According to a second aspect of the present invention, there is provided an apparatus for regenerating activated carbon to which a harmful gas is adsorbed, comprising a superheated steam supply unit for heating a harmful substance contained in the activated carbon to a temperature higher than its boiling point; An adsorbent installation section to which an activated carbon filter can be attached, and an exhaust treatment section, wherein the superheated steam supply section includes a steam generator and a heater for superheating, and supplies superheated steam to an activated carbon filter in the adsorbent installation section. In addition, a temperature sensor is provided on the downstream side of the adsorbent installation section, and a unit for decomposing desorbed gas separated from the activated carbon is provided in the exhaust treatment section, Provided is an activated carbon regenerating apparatus configured to regenerate activated carbon by injecting superheated steam into activated carbon, decompose desorbed gas, and discharge the decomposed gas to the atmosphere.
[0011]
In such an apparatus, activated carbon at atmospheric pressure is used for the regeneration of activated carbon. By introducing and filling superheated steam into activated carbon, which is a combustible material, oxygen required for combustion can be cut off, and the consumption of activated carbon is almost eliminated, and safety is secured. Since the pressure of the regeneration by the superheated steam is almost the same as the atmospheric pressure, the device does not need to have pressure resistance.
Since the superheated steam is used, there is no adsorption of moisture to the adsorbent in the case of the regeneration of the saturated steam, the drying step of the adsorbent after the regeneration is unnecessary, and the adsorbent does not re-adsorb contaminants in the drying step.
[0012]
Water molecules (H ₂ O) of superheated steam have larger energy for desorbing adsorbed substances than air molecules (N ₂ , O ₂ ) of hot air regeneration. High regeneration efficiency can be obtained.
The superheated steam exhaust gas after regeneration is directly introduced into the desorption gas decomposition unit to decompose chemical substances in the exhaust gas. After 95% or more of harmful gas (VOC) is purified by the decomposition treatment, it is discharged to the atmosphere.
[0013]
Further, according to the device of the present invention, the following operational effects can be obtained.
(1) Regeneration efficiency is good due to hydrothermal reaction of superheated steam and two-stage regeneration of low boiling point and high boiling point, and the adsorbent can be used semi-permanently. (2) Regeneration by superheated steam under atmospheric pressure, pressure-resistant structure It is not necessary and can be applied to an air conditioning system. (3) Since oxygen supply is shut off by filling the apparatus with superheated steam during regeneration, there is almost no loss due to consumption of activated carbon, and safe regeneration is possible (4). Since the desorbed gas in the exhaust gas at the time of regeneration is released into the atmosphere after being decomposed, it hardly pollutes the air. (5) When incorporated into an air conditioning system as an air purification device with a regeneration function, it can be operated at a high SV value. The amount of adsorbent used can be reduced to 1/3 to 1/15 of that of the conventional one, which saves resources and space. (6) When incorporated into an air conditioning system as an air purification device with a regeneration function, low pressure loss and energy saving are achieved. No additional booster fan is required, and it can be handled by the AHU's external static pressure.
[0014]
As a third aspect of the present invention, there is provided an air purification system having a mechanism for regenerating activated carbon adsorbing a harmful gas, comprising a fan or a blower for drawing air from a room to be air-conditioned and a filter unit including a dust filter. An air purification section including an activated carbon regeneration mechanism, an air conditioner, and a pipe connecting the same, the activated carbon regeneration mechanism includes a superheated steam supply section that heats a harmful substance contained in the activated carbon to a boiling point or higher, An adsorbent installation section that is held at atmospheric pressure and can be equipped with an activated carbon filter, and an exhaust treatment section are included.The superheated steam supply section has a steam generator and a heater for superheating, and supplies superheated steam. The activated carbon is supplied to an activated carbon filter in the adsorbent installation section and is injected into the activated carbon. A temperature sensor is provided downstream of the adsorbent installation section, The unit is provided with a unit that decomposes desorbed gas separated from activated carbon, injects superheated steam into activated carbon to regenerate activated carbon, and decomposes desorbed gas and discharges it to the atmosphere. Provide a purification system.
[0015]
According to such an air purification system, an air conditioning system including a VOC removal device with a regeneration function combined with an air purification device (activated carbon filter) is constructed. Since the regeneration steam is in a superheated state or at atmospheric pressure, a pressure-resistant container or the like is not required, and can be applied to an air conditioning system.
[0016]
The activated carbon filter for removing VOCs incorporated in the conventional air purification system has a short lifetime of activated carbon, so the SV value is set as low as 10,000 to 50,000 / h in order to avoid frequent replacement of the broken filter. . In that case, since the amount of activated carbon used is large, the pressure loss of the filter is as large as 400 Pa (when the SV value is 30,000 / h).
This activated carbon air purification system enables safe and effective regeneration even if the activated carbon filter breaks through, enabling an SV value of 150,000 / h. It is reduced to 1/3, resulting in space saving, resource saving, and cost saving. Further, by reducing the amount of activated carbon used, a low pressure loss of the filter is realized, and the air conditioner can be operated with an external static pressure without adding a booster fan, thereby saving energy and cost.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows an activated carbon regenerating apparatus according to a preferred embodiment of the present invention. By repeatedly using this regenerating device while changing the temperature conditions, the activated carbon can be subjected to the first-stage normal regeneration and the second-stage complete regeneration.
The regenerating apparatus 10 shown in FIG. 1 includes a superheated steam supply unit 12 for heating to a temperature higher than the boiling point of a harmful gas, an adsorbent installation unit 14 maintained at an atmospheric pressure, and an exhaust processing unit 16, each of which is connected to a pipe. Connected. The superheated steam supply section 12 includes a steam generator 18 and a superheater heater 20, and is connected to the adsorbent installation section 14 by piping. The adsorbent installation section 14 is provided with an activated carbon filter 22 that has adsorbed harmful gases and has passed therethrough, and a temperature sensor 24 is provided downstream of the activated carbon filter 22. The exhaust processing unit 16 includes an opening / closing damper VD1, an opening / closing damper VD2, a desorption gas decomposition unit 26, an air inlet 27, and a blower 28, and is connected by piping.
[0018]
In the regeneration device 10 of FIG. 1, the superheated steam is supplied from the superheated steam supply unit 12 to the adsorbent installation unit 14 maintained at the atmospheric pressure, and the activated carbon filter 22 that adsorbs harmful gas and breaks through is regenerated. The harmful gas (VOC) in the exhaust gas is purified by the desorption gas decomposition unit 26 of the exhaust processing unit 16 and then discharged to the atmosphere. The temperature sensor 24 detects the temperature of the adsorbent installation section 14 and adjusts the output of the overheating heater 20 so that the regeneration temperature is maintained at the set temperature.
[0019]
The decomposition method by the desorption gas decomposition unit 26 includes a decomposition method using a catalyst and a plasma decomposition method, and both methods can be adopted. As the catalyst used in the catalytic decomposition method, noble metals such as platinum and palladium, and base metals such as cobalt, chromium, manganese, vanadium oxide, and titanium dioxide can be used. The superheated steam exhaust gas after regeneration is directly introduced into the desorption gas decomposition unit, and the chemical substances in the exhaust gas can be decomposed by effectively using the residual heat of the regeneration exhaust gas. In particular, when platinum is used as a catalyst in the desorption gas decomposition unit, an auxiliary heater (not shown) is provided between the opening / closing damper VD1 of the exhaust processing unit 16 and the desorption gas decomposition unit 26 to maintain the reaction speed of the catalyst unit. Is provided. By operating the opening / closing dampers VD1 and VD2, the amount of air exhausted from the desorbing gas decomposing unit 26 and the amount of air taken in from the air inlet 27 is adjusted, and the inlet temperature of the blower 28 is kept below the heat resistant temperature of the blower. An appropriate amount of regenerated steam is secured in accordance with the pressure loss of 22.
[0020]
FIG. 2 shows an activated carbon regenerating apparatus according to another embodiment of the present invention. This regenerating apparatus 30 is characterized in that a circulating line 32 is provided in an adsorbent installation section 34 maintained at an atmospheric pressure. Have. The circulation line 32 includes a pipe 36, a blower 38, a superheater 40, and a temperature sensor 42. The circulation line 32 adsorbs harmful gas and breaks through with the downstream side of the first temperature sensor 24 provided in the adsorbent installation section 34. Each of them is connected to the upstream side of the activated carbon filter 22 via a pipe 36.
In the circulation line 32, a part of the exhaust gas is circulated by a blower 38, reheated by a superheater 40, mixed with superheated steam supplied from a superheated steam supply unit 12, and provided in an adsorbent installation unit 34. This is an example of a method used for regeneration of the activated carbon filter 22. This embodiment has an advantage that the energy required for overheating can be reduced as compared with the embodiment of FIG.
[0021]
FIG. 3 shows an activated carbon regenerating apparatus according to still another embodiment of the present invention. This regenerating apparatus 50 is characterized in that a purge line 52 is provided in an adsorbent installation section 54 maintained at an atmospheric pressure. Having. The purge line 52 includes an air inlet 55, a pipe 56, and an opening / closing damper MV <b> 1, and is connected to an upstream side of the activated carbon filter 22 that has adsorbed harmful gas and passed through the adsorbent installation section 54.
After the regeneration process, if the opening / closing damper MV1 is opened while the blower 28 is operating, purge air flows in and the activated carbon can be cooled quickly. In the case of the example of FIG. 2, the purge air intake 55 may be provided in the middle of the circulation line 32.
[0022]
FIG. 4 shows an embodiment of an air purification system incorporating the activated carbon regeneration device described above. The air purification system 60 includes a room 62 to be air-conditioned, a pipe 63 for connecting each device, an outlet 64 for taking out RA (return air) from the room 62 to be air-conditioned, an exhaust fan 66, and a dust filter 69. SA (supply air) is supplied to a filter unit 70 for introducing outside air from an inlet 68, an air purification device 72 including a rotary activated carbon filter 74 rotated by a motor 73, an air conditioner (AHU) 76, and a room 62 to be air-conditioned. An air supply port 78 is included.
[0023]
The rotary activated carbon filter 74 is of the type described in the above-mentioned JP-A-7-275636, and has a function of rotating and regenerating the filter portion. During normal air conditioning, the opening / closing damper MV1 of the cooling air inlet 75 is closed. During regeneration, superheated steam for regeneration from the steam generator 18 and the heater for superheating 20 is introduced, and at the same time, cooling air is introduced from the cooling air inlet 75 via the opening / closing damper MV1.
[0024]
In the room 62 to be air-conditioned, during normal air-conditioning operation, room air is taken out from the RA outlet 64 and a part of the air is exhausted by the exhaust fan 66. The remaining air and the outside air taken in from the outside air intake 68 are removed by a dust filter 69 installed in a filter unit 70, and harmful gases are adsorbed and removed by a rotary activated carbon filter 74 installed in an air purification device 72. , And sends clean air to the air conditioner 76. A desired air state (temperature / humidity) is set by the air conditioner 76, and air is supplied from the SA air supply port 78 to the room 62 to be air-conditioned.
[0025]
The activated carbon filter 74 rotates in the order of the adsorption section → the desorption section → the cooling section. At this time, the VOC concentration monitor 80 samples air from the upstream side and the downstream side of the rotary activated carbon filter 74 to determine whether or not the rotary activated carbon filter needs to be regenerated. The regeneration operation of the activated carbon filter 74 is performed during normal air conditioning operation or when air conditioning is stopped. The regeneration operation is performed by rotating the activated carbon filter 74 in the order of the desorption section, the cooling section, and the adsorption section. In the case of intermittent air conditioning, the regeneration operation may be performed when the air conditioning operation is stopped.
Although the rotary activated carbon filter 74 is used in this embodiment, a stationary activated carbon filter can be used.
[0026]
FIG. 5 shows a comparison between the effects of the atmospheric pressure superheated steam regeneration and the hot air regeneration according to the present invention. It has been proved that the regeneration method according to the present invention has much higher regeneration efficiency than the conventional hot air regeneration.
[0027]
Table 1 shows the results of comparing the present invention with a conventional activated carbon filter using the same honeycomb formed activated carbon.
[Table 1]

[0028]
Table 2 shows the activated carbon loss rate by the regeneration method of the present invention. Here, the activated carbon loss rate is defined as: (weight of new activated carbon−weight of activated carbon after regeneration) / (weight of new activated carbon) × 100.
[Table 2]

[0029]
【The invention's effect】
As described in detail above, according to the activated carbon regeneration method / regeneration apparatus of the present invention, the amount of activated carbon is reduced for a long time, the regeneration operation can be performed safely and with high regeneration efficiency, and the problem of air pollution can be solved. In the air purification system equipped with it, the activated carbon filter can be used semi-permanently, and the technical effect is extremely remarkable, such as the resource saving, the pressure loss of the activated carbon filter can be greatly reduced, and the energy saving effect is extremely large. There is.
[Brief description of the drawings]
FIG. 1 is a schematic circuit diagram of an activated carbon regeneration device according to the present invention.
FIG. 2 is a schematic circuit diagram of an activated carbon regeneration device according to another embodiment.
FIG. 3 is a schematic circuit diagram of an activated carbon regeneration device according to another embodiment.
FIG. 4 is a schematic circuit diagram of an air purification system including an activated carbon regeneration device.
FIG. 5 is a graph comparing the effects of atmospheric pressure superheated steam regeneration and hot air regeneration.
[Explanation of symbols]
10, 30, 50 Activated carbon regeneration device 12 Superheated steam supply unit 14 Adsorbent installation unit 16 Exhaust treatment unit 18 Steam generator 20 Heater for superheating 22, 74 Activated carbon filter 24 Temperature sensor 26 Desorption gas decomposition unit 28 Blower 60 Air purification system 62 Air-conditioned room 63 Pipe 66 Exhaust fan 69 Dust filter 70 Filter unit 72 Air purification device 76 Air conditioner

Claims

A method for regenerating activated carbon adsorbing harmful gas,
A first stage of regenerating by injecting superheated steam of 150 to 250 ° C. to the low boiling substance;
A method for regenerating activated carbon, characterized in that it is performed in combination with a second step of regenerating by injecting superheated steam at 300 to 350 ° C. to a high boiling substance.

A device for regenerating activated carbon adsorbing harmful gas,
A superheated steam supply unit for heating harmful substances contained in the activated carbon above its boiling point,
An adsorbent installation section that is maintained at atmospheric pressure and can be fitted with an activated carbon filter,
An exhaust processing unit,
The superheated steam supply unit includes a steam generator and a heater for superheating, and supplies the superheated steam to an activated carbon filter in the adsorbent installation unit and injects the activated carbon into activated carbon.
A temperature sensor is provided downstream of the adsorbent installation section,
The exhaust treatment unit is provided with a unit for decomposing the desorbed gas separated from the activated carbon,
An activated carbon regenerating apparatus characterized in that activated carbon is regenerated by injecting superheated steam into activated carbon and decomposed gas is decomposed and discharged into the atmosphere.

An air purification system having a mechanism for regenerating activated carbon adsorbing harmful gas,
A fan or blower that draws air from the room to be air-conditioned, a filter unit including a dust filter, an air purification section including an activated carbon regeneration mechanism, an air conditioner, and a pipe connecting them,
The activated carbon regeneration mechanism includes a superheated steam supply unit that heats a harmful substance contained in activated carbon to a temperature equal to or higher than its boiling point, an adsorbent installation unit that is maintained at atmospheric pressure and can be equipped with an activated carbon filter, and an exhaust treatment unit. And
The superheated steam supply unit has a steam generator and a heater for superheating, and supplies the superheated steam to an activated carbon filter in the adsorbent installation unit to inject the activated carbon,
A temperature sensor is provided downstream of the adsorbent installation section,
The exhaust treatment unit is provided with a unit for decomposing the desorbed gas separated from the activated carbon,
An air purification system characterized in that superheated steam is injected into activated carbon to regenerate activated carbon and decompose gas to decompose and discharge to the atmosphere.