JP2004033891A - Carbon carrier for carrying metal catalyst - Google Patents
Carbon carrier for carrying metal catalyst Download PDFInfo
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- JP2004033891A JP2004033891A JP2002193772A JP2002193772A JP2004033891A JP 2004033891 A JP2004033891 A JP 2004033891A JP 2002193772 A JP2002193772 A JP 2002193772A JP 2002193772 A JP2002193772 A JP 2002193772A JP 2004033891 A JP2004033891 A JP 2004033891A
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 127
- 239000003054 catalyst Substances 0.000 title claims abstract description 62
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 52
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 25
- 239000002184 metal Substances 0.000 title claims abstract description 25
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- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 abstract description 72
- 239000001257 hydrogen Substances 0.000 abstract description 70
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Images
Abstract
Description
【０００１】
【発明の属する技術分野】
本発明は金属触媒を担持させるカーボン担体に関し、より詳細には、各種芳香族化合物を水素化（水添）して水素を吸蔵させると共に、必要に応じて該芳香族化合物から水素を放出させる水素貯蔵放出システムに用いられる触媒に好適なカーボン担体に関するものである。
【０００２】
【従来の技術】
２００１年に開催された地球温暖化防止京都会議において、二酸化炭素排出量の大幅な削減目標が検討され、また将来の石油資源の枯渇に対する懸念もあって、近年、エネルギー利用の効率化や省エネルギー対策と共に、新たなエネルギー源の開発が急がれている。こうした背景から化学反応による燃料エネルギーを電力に変換して直接取出す燃料電池は、様々な分野において、二酸化炭素排出量削減に貢献する環境調和型電源として注目されている。特に自動車や家庭用の電源として、燃料電池の実用化研究は急速に発展してきている。
【０００３】
こうした状況の下で燃料電池として使用される水素の貯蔵・供給システムについては様々な技術が提案されており、例えば水素を液体水素や圧縮水素として貯蔵する技術が提案されている。しかしながら液体水素は液化する際の消費エネルギーが大きいばかりでなく、液体水素を極低温に保持するためのコストが高く、しかも保存安全性の問題がある。また圧縮水素の場合、現在の高圧化技術では、実用レベルの貯蔵量を確保するための貯蔵タンクが大型化してしまうという問題に加えて、保存のための安全対策も十分に確立されていない。
【０００４】
安全性の高い水素貯蔵手段として、水素吸蔵合金や、カーボンナノチューブなどの水素吸蔵材料を用いる技術が提案されている。しかし、水素吸蔵合金を用いる方法では、用いる合金質量当りの吸蔵量が少ないため、実用レベルの吸蔵量を確保するには膨大な量の合金が必要となり、設備が重くなるばかりか、合金に要するコストも高騰する。またカーボンナノチューブも、嵩密度が大きいため、体積当りの吸蔵量が少なく、やはり大型化しなければ実用レベルの吸蔵量を得ることはできない。
【０００５】
【発明が解決しようとする課題】
上記の如く燃料電池の実用化に向けて様々な水素吸蔵・供給技術が開発されているが、自動車等の如く限られたスペースに燃料電池システムを設置しなければならない分野で燃料電池の実用化を達成するには、燃料供給部のコンパクト化と、軽量化が大きな課題であり、且つ、より短時間で大量の水素を発生させることのできる技術の確立が必要となる。
【０００６】
この様な要望に適う比較的新しい技術として、芳香族化合物を水素の貯蔵・供給媒体として用いる技術が研究されている。例えばベンゼンやナフタレンなどの芳香族化合物を水素化し、シクロヘキサンやデカリンなどの水素化物として水素を貯蔵させ、使用時には該水素化物を脱水素反応させることによって水素を放出させて供給するシステムが提案されている。
【０００７】
このシステムでは、例えばベンゼンを水素化してシクロヘキサンとして水素を吸蔵させる場合（水素化反応）、装置内には予め本発明の金属担持触媒を設置しておき、水素を該装置内に導入すると共に、ヒーター等を用いて任意の方法でベンゼンを沸点以上に加熱して発生させた蒸気を、水冷など任意の方法で凝縮し、滴下するベンゼンを金属担持触媒と接触させてベンゼンの水素化反応を促進することによって、ベンゼンに水素が貯蔵（吸蔵）される。そして該水素化されたベンゼン（シクロヘキサン）から水素を放出させる場合（脱水素反応）、シクロヘキサンを沸点以上に加熱して蒸気を発生させ、該蒸気を凝縮して滴下する凝縮液を金属触媒と接触させるとシクロヘキサンの脱水素反応が促進され、シクロヘキサンから水素が放出される。そして該水素は、燃料として燃料電池等、任意の装置に供給することができる。
【０００８】
この様に水素化反応・脱水素反応を利用する技術においては、水素化（水添）・脱水素（水素放出）効率を高めるため各種の触媒が提案されている。例えばＰｔなどの金属触媒を粒状のシリカやアルミナに担持させた触媒が提案されている。しかしながらこれら粒状物は表面積が小さいため触媒担持量を十分に高めることができない。また表面積の大きな担体として粉末状活性炭を用いる技術も提案されているが、粉体間の空隙が小さいため十分な担持量は得られ難く、しかも粉末状活性炭は飛散し易く、取扱性が極めて悪いために実用的でない。尚、粉末状活性炭を造粒した粒状活性炭も提案されているが、強度が不充分で、粉化し易いという問題を有しているため、取扱性も悪い。
【０００９】
本発明はこれら従来技術に指摘される問題等に鑑みてなされたものであって、その目的は、大きな比表面積を有すると共に、十分な取扱性を有する担体、特に、水素化および脱水素反応の開始時間を短縮すると共に、反応効率を高め水素の貯蔵・放出量を増大させるのに有効な触媒担体を提供することにある。
【００１０】
【課題を解決するための手段】
上記課題を解決し得た本発明の触媒担体とは、金属触媒を担持するカーボン担体であって、該カーボン担体は担体厚み方向の通気性が２００ｃｍ３／ｃｍ２・ｓ（但し、ＪＩＳ Ｌ １０１８に基づく）以上の活性炭からなり、レーザーラマン法により求められる１３６０ｃｍ−１のピーク強度Ｉａと１５８０ｃｍ−１のピーク強度Ｉｇの関係が、０．９０≦Ｉａ／Ｉｇ≦１．５０であるところに要旨を有している。
【００１１】
また前記１３６０ｃｍ−１のピーク半値半幅が３０〜６０ｃｍ−１で、且つ前記１５８０ｃｍ−１のピーク半値半幅が３０〜４５ｃｍ−１であるものは、より優れた効果を発揮する上で推奨される。
【００１２】
本発明のカーボン担体は繊維状カーボンによって構成されていることが好ましく、更にカーボン担体が編物であること、特に、リブ編み又は両面編みされた編物は優れた効果を発揮させる上で望ましい。
【００１３】
本発明で用いるカーボン担体はトルエン吸着性能が２５ｇ／ｍ２（但し、温度：２５℃）以上であることが望ましい。
【００１４】
本発明の担体は、芳香族化合物の水素化反応を促進させ、また脱水素反応を促進させるための触媒担体として好適に用いることができる。
【００１５】
【発明の実施の形態】
本発明者らは前述した様な課題の解決を期して、鋭意研究を重ねた結果、金属触媒を担持するカーボン担体として、該担体厚み方向の通気性が２００ｃｍ３／ｃｍ２・ｓ以上であって、且つレーザーラマン法により求められる１３６０ｃｍ−１のピーク強度Ｉａと１５８０ｃｍ−１のピーク強度Ｉｇの関係が、０．９≦Ｉａ／Ｉｇ≦１．５であるものを使用すると、十分な取扱性を有し、特に水素化反応及び脱水素反応を効率よく進めるのに有効な触媒担体が得られることを見出し、本発明に至った。
【００１６】
本発明では、カーボン担体として、担体厚み方向の通気性が２００ｃｍ３／ｃｍ２・ｓ以上であることが必要である。通気性が２００ｃｍ３／ｃｍ２・ｓ未満では、担体内への反応物質の拡散が不充分となって反応効率が低くなり、例えば脱水素反応時の水素放出開始までの時間が遅く、且つ水素放出量も少なくなる。好ましくは２５０ｃｍ３／ｃｍ２・ｓ以上、より好ましくは３００ｃｍ３／ｃｍ２・ｓ以上である。尚、通気性が高いほど担体内での反応物質の拡散性が向上し、反応効率も向上するので、この様な観点からは上限は特に限定されないが、通気性を高くし過ぎると担体の強度が低下して取扱性が劣化することがあるので、好ましくは６００ｃｍ３／ｃｍ２・ｓ以下、より好ましくは５５０ｃｍ３／ｃｍ２・ｓ以下であることが望ましい。ここで通気性とは、ＪＩＳ Ｌ１０１８「ニット生地試験方法」に記載の方法に基づいて算出される値である。
【００１７】
本発明では、担体をレーザーラマン分光法によって求められる１３６０ｃｍ−１のピーク強度Ｉａと１５８０ｃｍ−１のピーク強度Ｉｇの関係が、０．９０≦Ｉａ／Ｉｇ≦１．５０であることが必要である。
【００１８】
１３６０ｃｍ−１に現れるピークは、炭素原子の結合が３次元的結合をなすもの（アモルファス）が存在していることを示し、また１５８０ｃｍ−１に現れるピークは、炭素原子の結合が２次元的結合をなすもの（グラファイト）が存在していることを示す。即ち、本発明の担体は、炭素原子の結合がアモルファスなものと、グラファイトなものを特定の割合で含んでいる。
【００１９】
グラファイトが多くなると、金属触媒と相互作用をなす担体の活性点（例えばグラファイト結晶子の端面）が減少するため、水素化反応・脱水素反応の効率が悪くなる。即ち、２次元的な結合を有する炭素構造がヘキゴナルグラファイトの場合、該ヘキゴナル平面の基底面（不活性面）と端面（活性面）が担体表面を形成するが、ピーク強度の関係（Ｉａ／Ｉｇ）が、０．９未満であると、担体表面を形成するヘキゴナル平面の端面が少なく、基底面が多くなるため、反応効率が悪くなるのである。この様な観点から好ましい下限は１．０、より好ましい下限は１．１である。
【００２０】
またアモルファスが多く、相対的にグラファイトが少ない場合、担体表面に占めるグラファイト結晶子の端面の割合も低いため、反応効率が悪くなる。即ち、ピーク強度の関係（Ｉａ／Ｉｇ）が、１．５を超えると、例えば担体表面に混在するヘキゴナル平面の端面の存在率が基底面の存在率より高くても、全体として担体活性点が少ないことから反応効率が悪くなる。好ましい上限は１．４５、より好ましい上限は１．４０である。
【００２１】
また本発明者らの研究によれば、ピーク強度が同程度であっても、担体のグラファイト化率や担体表面における上記炭素結晶構造体の分散度合いによって、反応効率が異なることから、３次元的な結合の炭素の存在率と、グラファイトの存在率（特にヘキゴナル平面の端面の存在率）をより適切に規定することが好ましい。この様な観点から本発明においては、１３６０ｃｍ−１のピーク半値半幅が好ましくは３０〜６０ｃｍ−１、より好ましくは３５〜５５ｃｍ−１である。また１５８０ｃｍ−１のピークの半値半幅が好ましくは３０〜４５ｃｍ−１、より好ましくは３２〜４３ｃｍ−１であることが望ましい。この様な半値半幅を有する担体表面には、グラファイト平面の端面の存在率が高いので望ましい。
【００２２】
上記の如きピーク強度と半値半幅を有する担体を用いた触媒を使用すると、水素化反応時には比較的短時間で芳香族化合物を水添でき、また脱水素反応時には、比較的短時間で水素化物から水素を放出させ、且つ水素放出量も増大するなど優れた触媒性能を発揮するので望ましい。
【００２３】
本発明においてレーザーラマン分光法により求められる担体の１５８０ｃｍ−１のピーク強度Ｉａと、１３６０ｃｍ−１のピーク強度Ｉｇとは、顕微ラマン分光装置（ジョバンイボンヌ−愛宕物産（株）製）を用いてＡｒイオンレーザー４８８ｎｍ線で１８００ｃｍ−１から１０００ｃｍ−１まで走査し、１３６０±２０ｃｍ−１のピーク（Ｉａ）と１５８０±２０ｃｍ−１のピーク（Ｉｇ）を解析したもので、各ピーク強度はベース補正を行った後、測定した波形をローレンツ関数で近似した最高点から求められる値である。またピークの半値半幅は、ピーク頂点の１／２の高さにおけるピーク幅の半分の値から求められる。
【００２４】
カーボン担体は、１０００ｍ２／ｇ以上、３０００ｍ２／ｇ以下の範囲の比表面積を有する活性炭を用いることが望ましい。比表面積が１０００ｍ２／ｇ未満では、芳香族化合物の吸着量が少ないため、水素化反応、脱水素反応の反応効率が十分に上がらず、転化率が不足となる。但し、比表面積が３０００ｍ２／ｇを超えると、担体としての強度が低下し、取扱性が悪化すると共に耐久性も低下して、長期使用に耐えなくなる。好ましくは１２００ｍ２／ｇ以上、２０００ｍ２／ｇ以下である。
【００２５】
上記比表面積とは、ＢＥＴ法によって求められる値である。具体的には、塩酸水溶液（１ｍｏｌ／Ｌ）で洗浄した後、充分に水洗し、１２〜７２時間予備乾燥させたサンプルを約０．１ｇ採取し、更に１２０℃で１２時間乾燥してから秤量し、液体窒素の沸点（−１９５．８℃）における窒素ガスの吸着量を、相対圧を０．０から０．２の範囲で徐々に高めながら数点（少なくとも４点以上）測定し、Ｂ．Ｅ．Ｔプロットにより求めた単位質量当たりの比表面積（ｍ２／ｇ）である。
【００２６】
本発明のカーボン担体を構成するカーボンの形状は特に限定されないが、粉状カーボンの場合、飛散し易く取扱性が悪いため好ましくない。また粉状カーボンを造粒してなる粒状カーボンは強度が十分でない。したがって取扱性に優れ、十分な強度を有する担体としては繊維状カーボンを用いることが望ましい。また繊維状カーボンは反応物質との接触面積となる外表面積が粒状カーボンよりも大きく、反応速度も早いため好ましい。尚、本発明の上記要件（通気率，ピーク強度）を満たす繊維状カーボンは、表面積が大きく、トルエン吸着力にも優れているにもかかわらず、繊維自身の強度の低下も抑制されているので、取扱性や耐久性にも優れている。繊維状カーボンの具体的なサイズについては限定されないが、例えば単繊維直径５〜１５μｍ、単繊維長さ０．１ｍｍ以上であることが望ましい。
【００２７】
繊維状カーボンを用いた担体の形態としては、例えば編物状、織物状、不織布状など各種の形態が挙げられる。これらの中でも繊維状カーボンを編物状に構成した担体を用いることが望ましい。担体として繊維状の活性炭で構成された編物を用いると、担体に適度な空隙と共に通気性が与えられ、芳香族化合物などの水素吸蔵媒体と触媒との接触面積を増大させることができ、また該空隙が脱水素反応によって放出させた水素を一次的に保持する空間としての機能も果たすので、装置内における水素保持スペース不足に起因する脱水素反応の効率低下を防ぐことができる。特に編組織がリブ編み又は両面編みのシートであるものは、本発明の担体を用いた触媒を水素貯蔵放出システムに充填した際に、より効果的な幾何表面積と空隙率を得ることができ、小さなスペースに充填した場合であっても脱水素反応によって放出した水素の存在スペースを十分に確保できるので望ましい。またフライス編みやスムース編みは、カーボン生地を焼成する際にコース方向に生じる収縮応力による該生地耳部の捲込みを殆ど生じないため、編物の利用可能有効幅を増大できるため望ましい。この際に使用する糸は、ステープルから得られる紡績糸、フィラメント糸状のいずれか、或いはこれらを混合した混繊糸状であってもよく、特に限定はされない。また単繊維繊度は好ましくは１．１ｄｔｅｘ以上、より好ましくは１．４ｄｔｅｘ以上であって、好ましくは５．５ｄｔｅｘ以下、より好ましくは５．０ｄｔｅｘ以下であることが取扱性を確保する観点から望ましい。更に撚合わせた糸状の繊度は好ましくは１５０ｄｔｅｘ以上、より好ましくは２９５ｄｔｅｘ以上であって、好ましくは５９０ｄｔｅｘ以下、より好ましくは４３０ｄｔｅｘ以下であることが望ましい。１５０ｄｔｅｘ未満の場合、担体を編物状にした際に、編物が緻密であるため密度が高くなりすぎて十分な通気性を確保できないことがある。また担体の柔軟性が不足して、加工時や使用時に破損が生じて取扱性が悪化することがある。一方、５９０ｄｔｅｘを超えると編組織が剛直となるため、炭化・賦活処理して得られる担体の取扱性が著しく低下することがある。
【００２８】
勿論、担体を織物状、或いは不織布状にして使用することも可能であるが、織物状の担体の場合、密度が高くなりすぎる傾向があるため、担体内に十分な空隙と、通気性が確保し難くなって、反応効率が低下し、また水素放出量が増大したときに、水素保持スペース不足に起因して脱水素反応が阻害される恐れもある。また不織布状の担体の場合、厚さ不足で十分な空隙を確保できず、また強度も不十分になることがある。
【００２９】
本発明のカーボン担体は、目付（ＪＩＳ Ｌ １０１８に基づく）が８０ｇ／ｍ２以上、より好ましくは１００ｇ／ｍ２以上であって、好ましくは２５０ｇ／ｍ２以下、より好ましくは２３０ｇ／ｍ２以下であることが望ましい。目付が８０ｇ／ｍ２未満では強度が不足となって、取扱性に問題が生じることがある。また２３０ｇ／ｍ２を超えると十分な通気性が得られないことがある。
【００３０】
本発明のカーボン担体は活性炭の特性の一つである吸着性能を有する。吸着性能は賦活化条件等によっても変わってくるため特に限定されないが、トルエン吸着性能試験による値が２５ｇ／ｍ２以上、好ましくは２７ｇ／ｍ２以上であることが望ましい。トルエン吸着性能が２５ｇ／ｍ２より小さい場合、効率的な反応を行なうために触媒充填量を増大しなければならず、装置が大型化してしまう。また担体の組織的強度を維持し、取扱性を確保する観点から、好ましくは９０ｇ／ｍ２以下、より好ましくは８５ｇ／ｍ２以下であることが望ましい。尚、トルエン吸着性能は、ＪＩＳ Ｋ１４７７「繊維状活性炭試験方法」の５．７項に記載のトルエン吸着性能試験（２５℃、１／１０希釈の条件下）に基づく値である。
【００３１】
該担体に担持する金属触媒は特に限定されず、例えばＮｉ，Ｃｏ，Ｆｅ，Ｃｒ，Ｃｕ，Ｖ，Ｐｒ，Ｍｇ，Ｍｏ，Ｗ、Ｍｎ，Ｚｎ，Ｇａ，Ｙ，Ｔｉ，Ｂａ、Ｒｅ，Ｂｉ，Ｎｂ，Ｔａ，Ｌａ，Ａｇ，Ａｕ，Ｐｄ、Ｐｔ、Ｒｈ、Ｒｕ、Ｏｓ、Ｉｒ等が例示される。本発明では金属触媒（金属酸化物等の各種化合物を含む）を単独で、或いは任意に組み合わせて用いることができる。これらの中でも白金族元素（Ｐｄ、Ｐｔ、Ｒｈ、Ｒｕ、Ｏｓ、Ｉｒ）は本発明の担体に担持することで、水素化、脱水素反応に対して高い触媒性能を発揮するため好ましい。また金属触媒の他にも助触媒など任意の添加物を担持させてもよい。
【００３２】
金属触媒の担持量は特に限定されず、所望量担持させればよく、例えば担体に対して好ましくは１〜１０質量％、より好ましくは２〜９質量％担持させることが望ましい。担持量が少ない場合、十分な触媒性能を発揮できないことがある。また担持量を多くすると、高コストとなると共に、コスト増大に見合う効果が得られないことがある。
【００３３】
担体に金属触媒を担持させる方法にも制限はなく、例えば所望の金属触媒をボールミル等により湿式粉砕してスラリーを製造し、該スラリーに担体を接触させればよい。或いは金属触媒を含む溶液に担体を接触させてもよい。金属触媒を均一に担持させる接触方法としては、担体をスラリーに浸漬させる方法が好適である。浸漬後、該担体を乾燥工程に付して水分を除去することが推奨される。この際の乾燥方法にも格別の限定はなく、任意の方法で水分を除去すればよい。乾燥時の条件も常温下、或いは高温下いずれであってもよい。また乾燥後に、焼成すると、金属触媒を担体に強固に定着できるので望ましい。焼成方法も特に限定されないが、例えば空気中、或いは任意の還元雰囲気下で４００〜８００℃で焼成すればよい。尚、上記担持方法で必要な担持量が得られない場合には、例えば焼成後に再度浸漬・乾燥・焼成を繰り返すことによって担持量を調整すればよい。また複数種の金属触媒を担持させるには、所望の金属触媒を含むスラリーや溶液を夫々製造し、浸漬・乾燥・焼成後、別のスラリーや溶液に浸漬させてから、乾燥・焼成してもよく、或いは金属触媒を複数種含むスラリーに浸漬させてもよく、任意の方法を採用できる。
【００３４】
このように金属触媒を本発明の上記カーボン担体に担持させてなる触媒は、耐久性に優れると共に、水素放出量も多く、また水素放出速度、水素放出開始までの時間も速く、極めて効率的な水素化・脱水素反応を行なうことができ、燃料電池用として好適に利用できる。
【００３５】
特に本発明の担体は、ベンゼン、トルエン、キシレン、メシチレンなどの単環芳香族化合物、ナフタレン、メチルナフタレンなど２環芳香族、およびアントラセンなどの３環芳香族に水素を吸蔵させる水素化反応、あるいは水素化物であるシクロヘキサン、メチルシクロヘキサン、ジメチルシクロヘキサンなどの２単環水素化芳香族化合物、テトラリン、デカリン、メチルデカリンなどの２環水素化芳香族化合物、テトラデカヒドロアントラセン、テトラデカヒドロメチルアントラセンなどの３環水素化芳香族化合物を脱水素して水素を取出す際に使用する触媒の担体として有用である。
【００３６】
芳香族化合物を触媒の存在下で水素化反応して、該化合物に水素を貯蔵させ、必要に応じて該水素化芳香族化合物を脱水素反応させ、該化合物から水素を放出させる水素貯蔵放出システムにおいて、該触媒として上記の如き本発明の担体を用いた触媒を使用すると、該化合物の水素化が効率的行なわれると共に、水素が貯蔵された該化合物から効率的に水素を放出させることができる。特に脱水素反応による水素放出開始までの時間を短縮できると共に、高効率で水素の放出を行なうことができるので、水素放出量も多くなる。したがって本発明の担体を用いた触媒を利用した水素貯蔵放出システムは燃料供給の安定性や、水素要求量の変化に迅速に対応でき、極めて効率的である。また水素化反応効率も向上するため、燃料チャージに要する時間を短縮できると共に、高い転化率を有するので水素貯蔵量も多くなる。
【００３７】
この様な水素貯蔵放出システムであれば、同一の装置で水素の添加・放出を行なうことができる。即ち水素の添加・放出に同一の触媒を使用することができるので、装置のコンパクト化を図ることができる。
【００３８】
以下、本発明のカーボン担体を製造方法に基づいて説明するが、本発明の担体は下記製造方法によって製造されたものに限定される趣旨ではなく、上記特性を付与できる製法あれば、いずれも採用できる。
【００３９】
本発明のカーボン担体に用いる炭素質物質としては、所謂、活性炭を用いることが望ましい。活性炭とは、多孔質で吸着性能を有するものである。この様な活性炭の原料としては例えば、大鋸屑などの木質物；籾殻，豆類，ヤシガラなどの植物；塩化ビニリデン樹脂，フラン樹脂，フェノール樹脂などの合成樹脂などが挙げられる。本発明では上述の如く、繊維状カーボンが望ましいので、例えばセルロース系，フェノールノボラック系，ポリアクリロニトリル系，芳香族ポリアミド系，ポリビニルアルコール系，ポリ塩化ビニル系，石油または石炭ピッチ系の有機物などの様に、炭化処理によって繊維状炭化物が得られる原料が望ましい。特にフェノール系の繊維を用いると、炭化処理時の収率が高く、また不純物含有量が少なく、更に炭化処理時におけるグラファイト構造の成長が他の原料と比べて低いので推奨される。
【００４０】
活性炭はこれら原料を炭化処理した後、賦活処理して得ることができる。また編物状担体を製造するには、予め繊維状の原料をリブ編みや両面編みなど任意の方法で編物とし、該編物を炭化処理・賦活処理すればよい。炭化処理と賦活処理は、連続的に行なってもよく、或いは各工程をバッチ式に行なってもよいが、均一な品質の活性炭を効率的に製造するには、連続的に炭化処理・賦活処理を行なうことが望ましい。また炭化処理と賦活処理を同時に行なってもよい。
【００４１】
炭化処理時の雰囲気としては、窒素やアルゴンなどの不活性雰囲気が好ましい。また炭化処理時の温度は、例えば所望の原料を不活性ガス雰囲気下で６００〜１０００℃に加熱して炭化すればよい。通常、６００℃以上に加熱すると、アモルファスが減少してグラファイトが増大するため、上記の如きピーク強度となる様に制御するには、該温度域での保持時間を調節してグラファイトの増加を抑制することが考えられるが、通常の処理でグラファイトの増大を抑制するには保持時間を極短時間にしなければならないが、保持時間を短くすると原料の炭化が不十分となるため、制御が極めて困難である。尚、６００℃未満で炭化すると担体表面に形成される細孔が少なくなり、また１０００℃を超えると強度が著しく低下する。したがって、本発明では上記活性炭を得る手段として、炭化処理時の昇温時間を制御すると共に、賦活条件を制御することが推奨される。
【００４２】
炭化処理時の昇温時間を従来よりも速くすることによって炭化時に形成されるグラファイトの生成を抑制し、アモルファスの減少を抑制しながら十分な炭化処理を達成できる。特に昇温速度を好ましくは１０℃／分以上、より好ましくは１５℃／分以上であって、好ましくは５０℃／分以下、より好ましくは４０℃／分以下とすることによって、Ｉａ／Ｉｇ値と半値半幅を上記の如く制御することができる。速い昇温時間を採用することによって、原料は十分に炭化されてアモルファスが確保されると共に、グラファイトの増大を抑制できる。尚、昇温時間が遅い場合、炭素の結晶構造が発達して担体表面を形成するグラファイトの端面の存在率よりも基底面の存在率が高くなり、担体の活性点が減少する。一方、昇温時間が早すぎる場合、原料を十分に炭化できず、担体として本発明の要求を満たし得ない。
【００４３】
この様な昇温時間を採用した場合の到達温度（６００〜１０００℃）での好ましい保持時間は０〜３０分である。該温度での保持時間が３０分以下であれば、原料の十分な炭化を図りつつ、アモルファスからグラファイトへの結晶構造の変化を抑制できる。
【００４４】
この様に原料を炭化処理して得られた炭化物を、炭素と反応する水蒸気、酸素、二酸化炭素などの賦活ガス雰囲気下での高温処理によって賦活処理する。
【００４５】
賦活処理時の温度は、好ましくは８００〜１０００℃、より好ましくは８５０〜９５０℃である。１０００℃を超えると異常収縮などによりしわが発生することがある。
【００４６】
炭化処理に引き続いて賦活処理を行なう場合、上記炭化時間保持後、雰囲気を炭素と反応する水蒸気、酸素、二酸化炭素などの賦活ガス雰囲気に変更し、引続き同温度で賦活処理することが望ましい。尚、水蒸気などの賦活剤を含有する雰囲気の場合、水蒸気の含有量は均一な賦活を行なうために５〜７５ｖｏｌ％（残部は窒素など任意の雰囲気でよい）とすることが好ましい。好ましくは１０〜６０ｖｏｌ％である。水蒸気含有量が少ない場合、十分な賦活が行なわれない。一方、水蒸気含有量が多い場合、水蒸気の拡散が不均一となり、担体の賦活が十分におこなえないことがある。
【００４７】
また該温度域での保持時間は、１０〜６０分、好ましくは１５〜４５分とすることが望ましい。保持時間が短い場合、得られる担体が十分に賦活されていないため、吸着力不足になることがある。また保持時間が長い場合、アモルファスが減少してグラファイトが増大するのみならず、グラファイト結晶子端面よりも基底面の存在率が高くなり、活性が劣化することがある。
【００４８】
この様な製造方法を採用することによって、担体厚み方向の通気性が２００ｃｍ３／ｃｍ２・ｓ（但し、ＪＩＳ Ｌ １０１８に基づく）以上の活性炭からなり、レーザーラマン法により求められる１３６０ｃｍ−１のピーク強度Ｉａと１５８０ｃｍ−１のピーク強度Ｉｇの関係が、０．９０≦Ｉａ／Ｉｇ≦１．５０であるカーボン担体を製造することができる。また１３６０ｃｍ−１のピーク半値半幅、及び１５８０ｃｍ−１のピーク半値半幅を上記の如く好適な範囲とすることが可能である。
【００４９】
特にフェノール系繊維を用い、リブ編み又は両面編みされた編物を上記炭化・賦活処理をすることによって、上記特性を有する担体を好適に製造できる。勿論、上記の如く製造されたカーボン担体はカーボン担体のトルエン吸着性能が２５ｇ／ｍ２（但し、温度：２５℃）以上であり、しかも目付が８０〜２５０ｇ／ｍ２、比表面積が１０００〜３０００ｍ２／ｇである担体である。
【００５０】
【実施例】
試験方法は特に記載しない限り、上述の方法に基づくものである。
【００５１】
実施例１
単繊維繊度２．２ｄｔｅｘで、糸状の繊度２９５ｄｔｅｘのフェノール系繊維を使用し、２２ゲージ両面丸編み機によりフライス編物を編成した。この編物は、目付２２５ｇ／ｍ２、厚さ１．６５ｍｍ、見掛比重０．１４ｇ／ｃｍ３、通気性は３２０ｃｍ３／ｃｍ２・ｓであった。この編物を不活性雰囲気下（Ｎ２）に設置し、温度を常温から８９０℃まで昇温（３０℃／分）して該編物を炭化した。更に８９０℃に到達した時点で雰囲気を水蒸気５０ｖｏｌ％含有雰囲気（残部：Ｎ２）に変更し、該温度（８９０℃）で３０分間保持し、賦活した。得られた編物（繊維状活性炭からなる担体）の目付、厚み、通気性、比表面積、トルエン吸着量、ラマンピーク強度比（＝Ｉａ／Ｉｇ）、ラマンスペクトル半値半幅を表１に示す。
【００５２】
実施例２
単繊維繊度２．２ｄｔｅｘで、糸状の繊度２９５ｄｔｅｘのフェノール系繊維を使用し、２２ゲージ両面丸編み機によりフライス編物を編成した。この編物は、目付２２５ｇ／ｍ２、厚さ１．６５ｍｍ、見掛比重０．１４ｇ／ｃｍ３、通気性は３２０ｃｍ３／ｃｍ２・ｓであった。この編物を不活性雰囲気下（Ｎ２）に設置し、温度を常温から８９０℃まで昇温（２０℃／分）して該編物を炭化した。更に８９０℃に達した時点で雰囲気を水蒸気５０ｖｏｌ％含有雰囲気（残部：Ｎ２）に変更し、該温度（８９０℃）で３０分間保持し、賦活した。得られた編物（繊維状活性炭からなる担体）の目付、厚み、通気性、比表面積、トルエン吸着量、ラマンピーク強度比（＝Ｉａ／Ｉｇ）、ラマンスペクトル半値半幅を表１に示す。
【００５３】
比較例１
単繊維繊度２．２ｄｔｅｘで、糸状の繊度１９７ｄｔｅｘのフェノール系繊維を使用し、２２ゲージ両面丸編み機によりスムース編物を編成した。この編物は、目付２３２ｇ／ｍ２、厚さ１．２０ｍｍ、見掛比重０．１９ｇ／ｃｍ３、通気性は１７０ｃｍ３／ｃｍ２・ｓであった。この編物を不活性雰囲気下（Ｎ２）に設置し、温度を常温から８９０℃まで昇温（３０℃／分）して該編物を炭化した。更に８９０℃に達した時点で雰囲気を水蒸気５０ｖｏｌ％含有雰囲気（残部：Ｎ２）に変更し、該温度（８９０℃）で３０分間保持して賦活した。得られた編物（繊維状活性炭からなる担体）の目付、厚み、通気性、比表面積、トルエン吸着量、ラマンピーク強度比（＝Ｉａ／Ｉｇ）、ラマンスペクトル半値半幅、触媒担時後の水素ガス放出量、水素放出開始までの時間を表１に示す。
【００５４】
比較例２
単繊維繊度２．２ｄｔｅｘで、糸状の繊度２９５ｄｔｅｘのフェノール系繊維を使用し、２２ゲージ両面丸編み機によりフライス編物を編成した。この編物は、目付２２５ｇ／ｍ２、厚さ１．６５ｍｍ、見掛比重０．１４ｇ／ｃｍ３、通気性は３２０ｃｍ３／ｃｍ２・ｓであった。この編物を不活性雰囲気下（Ｎ２）に設置し、常温から８９０℃まで昇温（５℃／分）した後、該温度で３０分間保持して該編物を炭化した。続いて雰囲気を水蒸気５０ｗｔ％含有雰囲気（残部：Ｎ２）とし、８９０℃で６０分間保持して賦活した。得られた編物（繊維状活性炭からなる担体）の目付、厚み、通気性、比表面積、トルエン吸着量、ラマンピーク強度比（＝Ｉａ／Ｉｇ）、ラマンスペクトル半値半幅を表１に示す。
【００５５】
比較例３
単繊維繊度２．２ｄｔｅｘで、糸状の繊度２９５ｄｔｅｘのフェノール系繊維を使用し、２２ゲージ両面丸編み機によりフライス編物を編成した。この編物は、目付２２５ｇ／ｍ２、厚さ１．６５ｍｍ、見掛比重０．１４ｇ／ｃｍ３、通気性は３２０ｃｍ３／ｃｍ２・ｓであった。この編物を不活性雰囲気下（Ｎ２）に設置し、温度を常温から８２０℃まで昇温（２℃／分）して該織物を炭化した。更に８２０℃に達した時点で雰囲気を水蒸気５０ｖｏｌ％含有雰囲気（残部：Ｎ２）に変更し、該温度（８２０℃）で６０分間保持して賦活した。得られた編物（繊維状活性炭からなる担体）の目付、厚み、通気性、比表面積、トルエン吸着量、ラマンピーク強度比（＝Ｉａ／Ｉｇ）、ラマンスペクトル半値半幅を表１に示す。
【００５６】
比較例４
粒径２５０〜５５０μｍの粒状に硬化させたノボラック樹脂をＮ２雰囲気下に設置し、温度を常温から８９０℃（３０℃／分）まで昇温した後、雰囲気を水蒸気５０ｖｏｌ％を含む雰囲気（残部：Ｎ２）に変更し、該温度（８９０℃）にて３０分間賦活処理した。得られた活性炭にバインダー（ポリアミド系バインダー，粒径２００〜７００μｍ）を混合し（配合比は活性炭：バインダー＝２：１）、該混合物をポリエステル系不織布（３０ｇ／ｍ２）に１８０ｇ／ｍ２となる様に均一に散布した後、２００℃で１０秒間加熱して活性炭シートを得た。得られた活性炭シートの目付、厚み、通気性、比表面積、トルエン吸着量、ラマンピーク強度比（＝Ｉａ／Ｉｇ）、ラマンスペクトル半値半幅を表１に示す。
【００５７】
水素放出量及び水素放出までの時間の測定方法
上記各担体に金属触媒（白金）を担持させた触媒を用いて水素ガス放出量、及び水素放出開始までの時間を調べた。尚、白金の担持方法は、いずれの実施例も、担体をＫ２ＰｔＣｌ４水溶液（５％）に４８時間浸漬した後、脱水乾燥し、更にＮａＢＨ４水溶液（５％）に浸漬した。浸漬後、予備乾燥して水分を除去してから、９０℃にて還元して白金（５質量％）担持触媒とした。得られた触媒（１０ｃｍ２）を図１に示す様な容器１内に載置し、窒素を充填した後に容器１を密閉した。該容器１を２００℃に加熱した帯状ヒーター３の上に載せ、５分間加熱した。加熱後、容器１内の触媒２に１０ｃｃのシクロヘキサンを触媒に均一に滴下（滴下時間：１分）し、水素ガス放出開始までの時間（分）、及び１時間経過後の水素ガス放出量（Ｌ）を測定（水素捕集管６）した。結果を表１に示す。
【００５８】
【表１】
尚、本発明の上記実施例の触媒は、装置内に充填する際に割れなどが生じず、取扱性に優れていた。また試験中、試験後も割れなどの不良が生じなかったために優れた取扱性を有していた。一方、比較例４の触媒は、柔軟性に乏しく、装置内に充填する際に割れが生じる等、取扱性が悪かった。また試験後、活性炭がポリエステル系不織布から剥がれ、装置内に充満した。
【００６０】
【発明の効果】
上記の如く本発明の担体は、担体の有効表面積を向上させつつ、十分な強度を確保し、取扱性にも優れている。また担体を構成する炭素の結晶構造を特定することで、触媒の活性を向上させることができる。したがって、本発明の担体に金属を担持してなる触媒を用いると、高い触媒性能を発揮し、効率的に化合物の水素化、及び脱水素反応を行なうことができる。この様に本発明の担体は、芳香族化合物の水素化反応／脱水素反応用触媒の担体として好適である。
【００６１】
また本発明の担体に触媒成分を担持させてなる触媒を用いた水素貯蔵放出システムは高効率で化合物に水素を添加、或いは水素の放出を行なうことができる。したがって本発明の担体に金属触媒を担持してなる触媒は、芳香族化合物を当該触媒の存在下で水素化して、該化合物に水素を貯蔵させると共に、必要に応じて該水素貯蔵物を該触媒の存在下で脱水素反応させ、該化合物から水素を放出させる機能を備えた水素貯蔵放出システムとして有効に活用できる。
【図面の簡単な説明】
【図１】本発明の実施例で用いた装置の概略図である。
【符号の説明】
１ 丸底フラスコ
２ 触媒担体
３ 電気ヒーター
４ 冷却管
５ コック
６ 水素捕集管
７ 冷却管
８ 芳香族回収部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a carbon support for supporting a metal catalyst, and more particularly, to hydrogenation (hydrogenation) of various aromatic compounds to occlude hydrogen and, if necessary, release of hydrogen from the aromatic compounds. The present invention relates to a carbon support suitable for a catalyst used in a storage and release system.
[0002]
[Prior art]
At the Kyoto Conference on Global Warming Prevention held in 2001, targets for significant reductions in carbon dioxide emissions were examined, and there were concerns about future depletion of petroleum resources. At the same time, the development of new energy sources is urgent. Against this background, fuel cells, which convert fuel energy by chemical reaction into electric power and directly extract it, have been attracting attention in various fields as environmentally friendly power sources that contribute to reducing carbon dioxide emissions. In particular, research on the practical application of fuel cells as power sources for automobiles and homes is rapidly developing.
[0003]
Under such circumstances, various technologies have been proposed for a hydrogen storage / supply system used as a fuel cell. For example, technologies for storing hydrogen as liquid hydrogen or compressed hydrogen have been proposed. However, liquid hydrogen not only consumes a large amount of energy when liquefied, but also has a high cost for maintaining liquid hydrogen at an extremely low temperature, and has a problem of storage safety. In the case of compressed hydrogen, the current high-pressure technology does not only have a problem that the storage tank for securing a practically usable storage amount becomes large, but also has not sufficiently established safety measures for storage.
[0004]
As a highly safe hydrogen storage means, a technique using a hydrogen storage material such as a hydrogen storage alloy or a carbon nanotube has been proposed. However, in the method using a hydrogen storage alloy, since the amount of occlusion per alloy mass used is small, an enormous amount of alloy is required to secure a practical level of occlusion, and not only the equipment becomes heavy but also the alloy requires Costs will rise. Further, since carbon nanotubes also have a large bulk density, the amount of occlusion per volume is small, and a practical level of occlusion cannot be obtained unless the size is also increased.
[0005]
[Problems to be solved by the invention]
As mentioned above, various hydrogen storage / supply technologies have been developed for the practical use of fuel cells, but the practical application of fuel cells in fields where fuel cell systems must be installed in limited spaces such as automobiles In order to achieve the above, it is important to make the fuel supply unit compact and lightweight, and it is necessary to establish a technology capable of generating a large amount of hydrogen in a shorter time.
[0006]
As a relatively new technology meeting such a demand, a technology using an aromatic compound as a hydrogen storage / supply medium has been studied. For example, a system has been proposed in which an aromatic compound such as benzene or naphthalene is hydrogenated, hydrogen is stored as a hydride such as cyclohexane or decalin, and when used, the hydride is dehydrogenated to release and supply hydrogen. I have.
[0007]
In this system, for example, when hydrogenating benzene to store hydrogen as cyclohexane (hydrogenation reaction), the metal-supported catalyst of the present invention is installed in the apparatus in advance, and hydrogen is introduced into the apparatus. Steam generated by heating benzene above the boiling point by any method using a heater or the like is condensed by any method such as water cooling, and the dropped benzene is brought into contact with a metal-supported catalyst to promote the benzene hydrogenation reaction. By doing so, hydrogen is stored (occluded) in benzene. When hydrogen is released from the hydrogenated benzene (cyclohexane) (dehydrogenation reaction), the cyclohexane is heated to a boiling point or higher to generate a vapor, and the vapor is condensed and the condensate dropped is brought into contact with a metal catalyst. This accelerates the dehydrogenation reaction of cyclohexane, and hydrogen is released from cyclohexane. The hydrogen can be supplied as a fuel to any device such as a fuel cell.
[0008]
As described above, in the technology utilizing the hydrogenation reaction / dehydrogenation reaction, various catalysts have been proposed in order to increase the hydrogenation (hydrogenation) / dehydrogenation (hydrogen release) efficiency. For example, a catalyst in which a metal catalyst such as Pt is supported on granular silica or alumina has been proposed. However, these particulates have a small surface area and cannot sufficiently increase the amount of supported catalyst. In addition, a technique using powdered activated carbon as a carrier having a large surface area has been proposed, but it is difficult to obtain a sufficient amount of the powder because the gap between the powders is small, and the powdered activated carbon is easily scattered, and the handling property is extremely poor. Not practical for. In addition, granular activated carbon obtained by granulating powdered activated carbon has been proposed, but it has a problem that the strength is insufficient and the powder is easily powdered.
[0009]
The present invention has been made in view of the problems and the like pointed out in these prior arts, and has an object to provide a carrier having a large specific surface area and sufficient handling properties, in particular, a hydrogenation and dehydrogenation reaction. It is an object of the present invention to provide a catalyst carrier which is effective for shortening the starting time, increasing the reaction efficiency and increasing the amount of hydrogen storage and release.
[0010]
[Means for Solving the Problems]
The catalyst carrier of the present invention which can solve the above problems is a carbon carrier carrying a metal catalyst, and the carbon carrier has a gas permeability of 200 cm in the thickness direction of the carrier. 3 / Cm 2 ・ It is made of activated carbon of s (based on JIS L 1018) or more, and is 1360 cm which is obtained by the laser Raman method. -1 Peak intensity Ia and 1580 cm -1 The point is that the relationship of the peak intensity Ig satisfies 0.90 ≦ Ia / Ig ≦ 1.50.
[0011]
1360cm -1 The half-width at half maximum of 30-60cm -1 And the above 1580cm -1 The half-width at half maximum of 30-45cm -1 Is recommended for better results.
[0012]
The carbon carrier of the present invention is preferably composed of fibrous carbon, and more preferably, the carbon carrier is a knitted fabric, and particularly, a knitted fabric that is rib-knitted or double-sided is preferable in order to exhibit excellent effects.
[0013]
The carbon carrier used in the present invention has a toluene adsorption performance of 25 g / m 2 (However, the temperature is preferably 25 ° C.) or more.
[0014]
The carrier of the present invention can be suitably used as a catalyst carrier for promoting the hydrogenation reaction of an aromatic compound and for promoting the dehydrogenation reaction.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
The present inventors have conducted intensive studies in an attempt to solve the problems as described above, and as a result, as a carbon support supporting a metal catalyst, the gas permeability in the thickness direction of the support was 200 cm. 3 / Cm 2 1s or more and 1360 cm determined by the laser Raman method -1 Peak intensity Ia and 1580 cm -1 When the relationship between the peak intensities Ig of 0.9 ≦ Ia / Ig ≦ 1.5 is used, it has sufficient handling properties, and is particularly effective for efficiently proceeding the hydrogenation reaction and the dehydrogenation reaction. The inventors have found that a catalyst carrier can be obtained, and have reached the present invention.
[0016]
In the present invention, as the carbon support, the permeability in the thickness direction of the support is 200 cm. 3 / Cm 2 -It must be s or more. Breathability is 200cm 3 / Cm 2 If it is less than s, the diffusion of the reactants into the carrier becomes insufficient and the reaction efficiency is reduced, for example, the time until the start of hydrogen release in the dehydrogenation reaction is slow, and the amount of hydrogen release is also small. Preferably 250cm 3 / Cm 2 -S or more, more preferably 300 cm 3 / Cm 2 -It is s or more. The higher the gas permeability, the higher the diffusivity of the reactants in the carrier and the higher the reaction efficiency. Therefore, the upper limit is not particularly limited from this viewpoint. Is preferably 600 cm. 3 / Cm 2 S or less, more preferably 550 cm 3 / Cm 2 -It is desirable that it is s or less. Here, the air permeability is a value calculated based on the method described in JIS L1018 “Knit fabric test method”.
[0017]
In the present invention, the carrier is 1360 cm which is determined by laser Raman spectroscopy. -1 Peak intensity Ia and 1580 cm -1 It is necessary that the relationship between the peak intensities Ig is 0.90 ≦ Ia / Ig ≦ 1.50.
[0018]
1360cm -1 The peaks appearing at 1580 cm indicate that carbon atoms form a three-dimensional bond (amorphous). -1 Indicates that there is a carbon atom bond that forms a two-dimensional bond (graphite). That is, the carrier of the present invention contains amorphous carbon atoms and graphite atoms in a specific ratio.
[0019]
When the amount of graphite increases, the number of active sites (for example, end faces of graphite crystallites) of the carrier that interacts with the metal catalyst decreases, so that the efficiency of the hydrogenation reaction / dehydrogenation reaction deteriorates. That is, when the carbon structure having a two-dimensional bond is hexagonal graphite, the base surface (inactive surface) and the end surface (active surface) of the hexonal plane form the carrier surface, but the relationship between the peak intensities (Ia If (/ Ig) is less than 0.9, the end surface of the hexonal plane forming the carrier surface is small and the basal plane is large, so that the reaction efficiency is poor. From such a viewpoint, a preferred lower limit is 1.0, and a more preferred lower limit is 1.1.
[0020]
When the amount of amorphous is large and the amount of graphite is relatively small, the ratio of the end face of the graphite crystallite to the surface of the carrier is low, so that the reaction efficiency is deteriorated. That is, when the relationship of peak intensities (Ia / Ig) exceeds 1.5, for example, even if the abundance ratio of the end surface of the hexagonal plane mixed on the carrier surface is higher than the abundance ratio of the basal plane, the carrier active site as a whole is Since the amount is small, the reaction efficiency deteriorates. A preferred upper limit is 1.45, and a more preferred upper limit is 1.40.
[0021]
According to the study of the present inventors, even if the peak intensities are almost the same, the reaction efficiency varies depending on the degree of graphitization of the support and the degree of dispersion of the carbon crystal structure on the support surface. It is preferable to more appropriately define the abundance ratio of carbon having a suitable bond and the abundance ratio of graphite (especially, the abundance ratio of an end surface of a hexagonal plane). From such a viewpoint, in the present invention, 1360 cm -1 Is preferably 30 to 60 cm. -1 , More preferably 35-55 cm -1 It is. Also 1580cm -1 Is preferably 30 to 45 cm. -1 , More preferably 32-43 cm -1 It is desirable that Such a carrier surface having a half width at half maximum is desirable because of the high abundance of the end face of the graphite plane.
[0022]
When a catalyst using a carrier having a peak intensity and a half width at half maximum as described above is used, an aromatic compound can be hydrogenated in a relatively short time during a hydrogenation reaction, and from a hydride in a relatively short time during a dehydrogenation reaction. It is desirable because it exhibits excellent catalytic performance such as releasing hydrogen and increasing the amount of released hydrogen.
[0023]
1580 cm of carrier determined by laser Raman spectroscopy in the present invention -1 Peak intensity Ia and 1360 cm -1 Is the peak intensity Ig of 1800 cm with a 488 nm line of an Ar ion laser using a micro Raman spectrometer (Joban Yvonne-Atago Bussan Co., Ltd.). -1 From 1000cm -1 Scan to 1360 ± 20cm -1 Peak (Ia) and 1580 ± 20 cm -1 The peak intensity (Ig) is analyzed, and each peak intensity is a value obtained from the highest point obtained by performing a base correction and then approximating a measured waveform by a Lorentz function. The half width at half maximum of the peak is obtained from half the value of the peak width at half the height of the peak apex.
[0024]
The carbon carrier is 1000m 2 / G or more, 3000m 2 It is desirable to use activated carbon having a specific surface area in the range of / g or less. Specific surface area is 1000m 2 If it is less than / g, the adsorption amount of the aromatic compound is small, so that the reaction efficiency of the hydrogenation reaction and the dehydrogenation reaction is not sufficiently increased, and the conversion is insufficient. However, the specific surface area is 3000m 2 If it exceeds / g, the strength as a carrier is reduced, the handleability is deteriorated, the durability is also reduced, and it cannot withstand long-term use. Preferably 1200m 2 / G or more, 2000m 2 / G or less.
[0025]
The specific surface area is a value determined by the BET method. Specifically, after washing with an aqueous hydrochloric acid solution (1 mol / L), the sample was sufficiently washed with water, and preliminarily dried for 12 to 72 hours, about 0.1 g of a sample was taken, further dried at 120 ° C. for 12 hours, and then weighed. Then, the amount of nitrogen gas adsorbed at the boiling point of liquid nitrogen (-195.8 ° C.) was measured at several points (at least four points) while gradually increasing the relative pressure in the range of 0.0 to 0.2. . E. FIG. Specific surface area per unit mass (m 2 / G).
[0026]
The shape of the carbon constituting the carbon support of the present invention is not particularly limited, but powdered carbon is not preferred because it is easily scattered and has poor handling properties. Also, granular carbon obtained by granulating powdery carbon has insufficient strength. Therefore, it is desirable to use fibrous carbon as a carrier having excellent handleability and sufficient strength. In addition, fibrous carbon is preferable because it has a larger external surface area as a contact area with a reactant than granular carbon and has a high reaction rate. In addition, the fibrous carbon satisfying the above requirements (air permeability, peak strength) of the present invention has a large surface area and excellent toluene adsorbing power. Also, it is excellent in handling and durability. Although the specific size of the fibrous carbon is not limited, for example, it is preferable that the diameter of the single fiber is 5 to 15 μm and the length of the single fiber is 0.1 mm or more.
[0027]
Examples of the form of the carrier using fibrous carbon include various forms such as a knitted form, a woven form, and a non-woven form. Among these, it is desirable to use a carrier in which fibrous carbon is formed in a knitted shape. When a knitted fabric composed of fibrous activated carbon is used as the carrier, the carrier is provided with air permeability along with appropriate voids, and the contact area between the hydrogen storage medium such as an aromatic compound and the catalyst can be increased. Since the void also functions as a space for temporarily holding the hydrogen released by the dehydrogenation reaction, it is possible to prevent a decrease in the efficiency of the dehydrogenation reaction due to a shortage of the hydrogen holding space in the device. In particular, when the knitting structure is a rib-knitted or double-sided knitted sheet, a more effective geometric surface area and porosity can be obtained when the catalyst using the carrier of the present invention is filled in a hydrogen storage and release system, Even if the space is filled in a small space, it is desirable because a sufficient space for the hydrogen released by the dehydrogenation reaction can be secured. Also, milling or smooth knitting is desirable because the shrinkage stress generated in the course direction when firing the carbon fabric hardly causes the fabric ear to be rolled up, so that the available effective width of the knitted fabric can be increased. The yarn used at this time may be a spun yarn obtained from staples, a filament yarn, or a mixed fiber obtained by mixing these, and is not particularly limited. Further, the single fiber fineness is preferably 1.1 dtex or more, more preferably 1.4 dtex or more, preferably 5.5 dtex or less, more preferably 5.0 dtex or less, from the viewpoint of ensuring handleability. Further, the fineness of the twisted thread is preferably at least 150 dtex, more preferably at least 295 dtex, preferably at most 590 dtex, more preferably at most 430 dtex. When it is less than 150 dtex, when the carrier is formed into a knitted fabric, the knitted fabric is dense and the density becomes too high, so that sufficient air permeability may not be secured. In addition, the flexibility of the carrier is insufficient, and the carrier may be damaged during processing or use, resulting in poor handling. On the other hand, if it exceeds 590 dtex, the knitted structure becomes rigid, so that the handleability of the carrier obtained by the carbonization and activation treatment may be significantly reduced.
[0028]
Of course, the carrier can be used in the form of a woven or non-woven fabric, but in the case of a woven carrier, the density tends to be too high, so that sufficient voids and air permeability in the carrier are ensured. When the reaction efficiency is lowered and the amount of released hydrogen is increased, the dehydrogenation reaction may be hindered due to insufficient hydrogen holding space. In the case of a non-woven carrier, sufficient voids cannot be secured due to insufficient thickness, and strength may be insufficient.
[0029]
The carbon support of the present invention has a basis weight (based on JIS L 1018) of 80 g / m. 2 Above, more preferably 100 g / m 2 Above, preferably 250 g / m 2 Or less, more preferably 230 g / m 2 It is desirable that: 80g / m 2 If it is less than the strength, the strength becomes insufficient, and a problem may occur in the handling property. 230g / m 2 If it exceeds 30, sufficient air permeability may not be obtained.
[0030]
The carbon support of the present invention has an adsorption performance which is one of the characteristics of activated carbon. The adsorption performance is not particularly limited because it varies depending on the activation conditions and the like, but the value obtained by the toluene adsorption performance test is 25 g /
[0031]
The metal catalyst supported on the carrier is not particularly limited. For example, Ni, Co, Fe, Cr, Cu, V, Pr, Mg, Mo, W, Mn, Zn, Ga, Y, Ti, Ba, Re, Bi, Examples include Nb, Ta, La, Ag, Au, Pd, Pt, Rh, Ru, Os, Ir, and the like. In the present invention, metal catalysts (including various compounds such as metal oxides) can be used alone or in any combination. Among these, platinum group elements (Pd, Pt, Rh, Ru, Os, Ir) are preferable because they can exhibit high catalytic performance for hydrogenation and dehydrogenation reactions by being supported on the carrier of the present invention. In addition to the metal catalyst, any additive such as a co-catalyst may be supported.
[0032]
The loading amount of the metal catalyst is not particularly limited, and may be a desired amount. For example, it is preferably 1 to 10% by mass, more preferably 2 to 9% by mass, based on the carrier. When the supported amount is small, sufficient catalytic performance may not be exhibited. In addition, when the carrying amount is increased, the cost is increased and the effect corresponding to the cost increase may not be obtained.
[0033]
The method for supporting the metal catalyst on the carrier is not particularly limited. For example, a slurry may be produced by wet-pulverizing a desired metal catalyst with a ball mill or the like, and the carrier may be brought into contact with the slurry. Alternatively, the carrier may be brought into contact with a solution containing a metal catalyst. As a contact method for uniformly supporting the metal catalyst, a method in which the carrier is immersed in a slurry is preferable. After immersion, it is recommended that the carrier be subjected to a drying step to remove moisture. The drying method at this time is not particularly limited, and moisture may be removed by an arbitrary method. Drying conditions may be either normal temperature or high temperature. Further, firing after drying is desirable because the metal catalyst can be firmly fixed to the carrier. The firing method is not particularly limited, but firing may be performed at 400 to 800 ° C. in the air or in an arbitrary reducing atmosphere. If the required supporting amount cannot be obtained by the above supporting method, the supporting amount may be adjusted, for example, by repeating immersion, drying and firing after firing. Also, in order to support a plurality of types of metal catalysts, a slurry or solution containing the desired metal catalyst is manufactured, dipped, dried, and fired, then immersed in another slurry or solution, and then dried and fired. Alternatively, it may be immersed in a slurry containing a plurality of types of metal catalysts, and any method can be adopted.
[0034]
As described above, the metal catalyst supported on the carbon carrier of the present invention has excellent durability, a large amount of hydrogen release, a high hydrogen release rate, and a fast time to the start of hydrogen release, which is extremely efficient. Hydrogenation / dehydrogenation reaction can be performed, and it can be suitably used for fuel cells.
[0035]
In particular, the carrier of the present invention is a hydrogenation reaction for storing hydrogen in a monocyclic aromatic compound such as benzene, toluene, xylene and mesitylene, a bicyclic aromatic compound such as naphthalene and methylnaphthalene, and a tricyclic aromatic compound such as anthracene, or Hydrogenated cyclohexane, methylcyclohexane, bicyclic monocyclic hydrogenated aromatic compounds such as dimethylcyclohexane, tetralin, decalin, bicyclic hydrogenated aromatic compounds such as methyldecalin, tetradecahydroanthracene, tetradecahydromethylanthracene, etc. It is useful as a carrier for a catalyst used in removing hydrogen by dehydrogenating a 3-ring hydrogenated aromatic compound.
[0036]
A hydrogen storage and release system that hydrogenates an aromatic compound in the presence of a catalyst to cause the compound to store hydrogen and, if necessary, dehydrogenates the hydrogenated aromatic compound and releases hydrogen from the compound. In the above, when a catalyst using the carrier of the present invention as described above is used as the catalyst, the compound can be efficiently hydrogenated, and hydrogen can be efficiently released from the compound in which hydrogen is stored. . In particular, the time until the start of hydrogen release by the dehydrogenation reaction can be shortened, and hydrogen can be released with high efficiency, so that the amount of released hydrogen increases. Therefore, the hydrogen storage and release system using the catalyst using the carrier of the present invention is very efficient because it can quickly respond to changes in fuel supply stability and hydrogen demand. Further, the hydrogenation reaction efficiency is improved, so that the time required for fuel charging can be shortened, and the high conversion rate increases the hydrogen storage amount.
[0037]
With such a hydrogen storage and release system, the same device can add and release hydrogen. That is, the same catalyst can be used for the addition and release of hydrogen, so that the apparatus can be made compact.
[0038]
Hereinafter, the carbon carrier of the present invention will be described based on a production method, but the carrier of the present invention is not limited to the one produced by the following production method, and any of the production methods that can impart the above characteristics is adopted. it can.
[0039]
As the carbonaceous substance used for the carbon support of the present invention, it is desirable to use so-called activated carbon. Activated carbon is porous and has adsorption performance. Examples of the raw material of such activated carbon include woody substances such as sawdust; plants such as rice husks, beans and coconut shells; and synthetic resins such as vinylidene chloride resin, furan resin and phenol resin. In the present invention, as described above, fibrous carbon is desirable. For example, cellulose-based, phenol novolak-based, polyacrylonitrile-based, aromatic polyamide-based, polyvinyl alcohol-based, polyvinyl chloride-based, petroleum or coal pitch-based organic substances, etc. In addition, a raw material from which a fibrous carbide can be obtained by carbonization is desirable. In particular, the use of phenolic fibers is recommended because the yield during carbonization is high, the content of impurities is small, and the growth of the graphite structure during carbonization is lower than other raw materials.
[0040]
Activated carbon can be obtained by carbonizing these raw materials and then activating them. In order to produce a knitted carrier, a fibrous raw material may be made into a knitted material by any method such as rib knitting or double-sided knitting, and the knitted material may be carbonized and activated. The carbonization treatment and the activation treatment may be performed continuously or each step may be performed in a batch manner. However, in order to efficiently produce activated carbon of uniform quality, the carbonization treatment and the activation treatment are continuously performed. It is desirable to perform Further, the carbonization treatment and the activation treatment may be performed simultaneously.
[0041]
As the atmosphere during the carbonization treatment, an inert atmosphere such as nitrogen or argon is preferable. The temperature during the carbonization treatment may be, for example, heating the desired raw material to 600 to 1000 ° C. in an inert gas atmosphere to carbonize. Usually, when heated to 600 ° C. or more, amorphous decreases and graphite increases. Therefore, in order to control the peak intensity as described above, the holding time in the temperature range is adjusted to suppress the increase in graphite. Although it is conceivable that the holding time must be extremely short in order to suppress the increase of graphite in normal processing, control is extremely difficult because the carbonization of the raw material becomes insufficient if the holding time is shortened It is. When carbonized at a temperature lower than 600 ° C., the number of pores formed on the surface of the support decreases, and when the temperature exceeds 1000 ° C., the strength is significantly reduced. Therefore, in the present invention, as means for obtaining the activated carbon, it is recommended to control the heating time during the carbonization treatment and to control the activation conditions.
[0042]
By making the temperature rise time during the carbonization process shorter than before, it is possible to suppress the generation of graphite formed during the carbonization and to achieve a sufficient carbonization process while suppressing the reduction of the amorphous phase. In particular, the Ia / Ig value is preferably set at a rate of 10 ° C./min or more, more preferably 15 ° C./min or more, preferably 50 ° C./min or less, more preferably 40 ° C./min or less. And the half width at half maximum can be controlled as described above. By adopting a fast heating time, the raw material is sufficiently carbonized to ensure an amorphous state, and the increase in graphite can be suppressed. If the temperature rise time is slow, the abundance of the basal plane becomes higher than the abundance of the end face of graphite forming the support surface due to the development of the crystal structure of carbon, and the active sites of the support decrease. On the other hand, if the heating time is too short, the raw material cannot be sufficiently carbonized, and the requirements of the present invention cannot be satisfied as a carrier.
[0043]
The preferred holding time at the ultimate temperature (600 to 1000 ° C.) when such a heating time is employed is 0 to 30 minutes. If the holding time at this temperature is 30 minutes or less, the change in the crystal structure from amorphous to graphite can be suppressed while sufficiently carbonizing the raw material.
[0044]
The carbide obtained by carbonizing the raw material in this manner is activated by a high-temperature treatment in an atmosphere of an activating gas such as steam, oxygen, carbon dioxide or the like which reacts with carbon.
[0045]
The temperature at the time of the activation treatment is preferably 800 to 1000C, more preferably 850 to 950C. If the temperature exceeds 1000 ° C., wrinkles may occur due to abnormal shrinkage or the like.
[0046]
In the case of performing the activation treatment subsequent to the carbonization treatment, it is preferable that after the carbonization time is maintained, the atmosphere is changed to an activation gas atmosphere such as water vapor, oxygen, carbon dioxide or the like which reacts with carbon, and the activation treatment is subsequently performed at the same temperature. In the case of an atmosphere containing an activator such as steam, the content of steam is preferably 5 to 75 vol% (the remainder may be an arbitrary atmosphere such as nitrogen) in order to perform uniform activation. Preferably it is 10 to 60 vol%. When the water vapor content is small, sufficient activation is not performed. On the other hand, when the water vapor content is high, the diffusion of the water vapor becomes non-uniform, and the activation of the carrier may not be sufficiently performed.
[0047]
The holding time in the temperature range is desirably 10 to 60 minutes, preferably 15 to 45 minutes. When the holding time is short, the obtained carrier is not sufficiently activated, so that the adsorbing power may be insufficient. In addition, when the retention time is long, not only the amorphous content decreases and graphite increases, but also the abundance ratio of the basal plane becomes higher than the graphite crystallite end face, and the activity may deteriorate.
[0048]
By adopting such a manufacturing method, air permeability in the thickness direction of the carrier is 200 cm. 3 / Cm 2 ・ It is made of activated carbon of s (based on JIS L 1018) or more, and is 1360 cm which is obtained by the laser Raman method. -1 Peak intensity Ia and 1580 cm -1 Can be produced with a relation of 0.90 ≦ Ia / Ig ≦ 1.50. Also 1360cm -1 Peak half width at half maximum and 1580 cm -1 Can be set in the preferable range as described above.
[0049]
In particular, a carrier having the above characteristics can be suitably produced by subjecting a knitted fabric knitted with ribs or both sides to the above-mentioned carbonization and activation treatment using a phenolic fiber. Needless to say, the carbon carrier produced as described above has a toluene adsorption capacity of 25 g /
[0050]
【Example】
The test method is based on the method described above unless otherwise specified.
[0051]
Example 1
Using a phenol-based fiber having a single fiber fineness of 2.2 dtex and a thread-like fineness of 295 dtex, a milled knit was knitted with a 22-gauge double-sided circular knitting machine. This knitted fabric has a basis weight of 225 g / m. 2 , Thickness 1.65mm, apparent specific gravity 0.14g / cm 3 , Air permeability is 320cm 3 / Cm 2 -It was s. This knit is placed under an inert atmosphere (N 2 ), And the temperature was increased from normal temperature to 890 ° C. (30 ° C./min) to carbonize the knitted fabric. Further, when the temperature reached 890 ° C., the atmosphere was changed to an atmosphere containing 50 vol% of water vapor (remainder: N 2 ) And maintained at the temperature (890 ° C.) for 30 minutes to activate. Table 1 shows the basis weight, thickness, air permeability, specific surface area, toluene adsorption amount, Raman peak intensity ratio (= Ia / Ig), and half width at half maximum of the Raman spectrum of the obtained knitted fabric (carrier made of fibrous activated carbon).
[0052]
Example 2
Using a phenol-based fiber having a single fiber fineness of 2.2 dtex and a thread-like fineness of 295 dtex, a milled knit was knitted with a 22-gauge double-sided circular knitting machine. This knitted fabric has a basis weight of 225 g / m. 2 , Thickness 1.65mm, apparent specific gravity 0.14g / cm 3 , Air permeability is 320cm 3 / Cm 2 -It was s. This knit is placed under an inert atmosphere (N 2 ), And the temperature was increased from normal temperature to 890 ° C. (20 ° C./min) to carbonize the knitted fabric. Further, when the temperature reached 890 ° C., the atmosphere was changed to an atmosphere containing 50 vol% of steam (remainder: N 2 ) And maintained at the temperature (890 ° C.) for 30 minutes to activate. Table 1 shows the basis weight, thickness, air permeability, specific surface area, toluene adsorption amount, Raman peak intensity ratio (= Ia / Ig), and half width at half maximum of the Raman spectrum of the obtained knitted fabric (carrier made of fibrous activated carbon).
[0053]
Comparative Example 1
Using a phenol-based fiber having a single fiber fineness of 2.2 dtex and a thread-like fineness of 197 dtex, a smooth knitted fabric was knitted with a 22-gauge double-sided circular knitting machine. This knitted fabric has a basis weight of 232 g / m. 2 , Thickness 1.20mm, apparent specific gravity 0.19g / cm 3 170cm breathable 3 / Cm 2 -It was s. This knit is placed under an inert atmosphere (N 2 ), And the temperature was increased from normal temperature to 890 ° C. (30 ° C./min) to carbonize the knitted fabric. Further, when the temperature reached 890 ° C., the atmosphere was changed to an atmosphere containing 50 vol% of steam (remainder: N 2 ) And maintained at the temperature (890 ° C.) for 30 minutes to activate. Weight, thickness, air permeability, specific surface area, toluene adsorption amount, Raman peak intensity ratio (= Ia / Ig), Raman spectrum half width at half maximum of Raman spectrum, hydrogen gas after catalyst loading Table 1 shows the release amount and the time until the start of hydrogen release.
[0054]
Comparative Example 2
Using a phenol-based fiber having a single fiber fineness of 2.2 dtex and a thread-like fineness of 295 dtex, a milled knit was knitted with a 22-gauge double-sided circular knitting machine. This knitted fabric has a basis weight of 225 g / m. 2 , Thickness 1.65mm, apparent specific gravity 0.14g / cm 3 , Air permeability is 320cm 3 / Cm 2 -It was s. This knit is placed under an inert atmosphere (N 2 ), The temperature was raised from room temperature to 890 ° C. (5 ° C./min), and the temperature was maintained at that temperature for 30 minutes to carbonize the knitted fabric. Subsequently, the atmosphere was changed to an atmosphere containing 50 wt% of steam (remainder: N 2 ) And kept at 890 ° C. for 60 minutes for activation. Table 1 shows the basis weight, thickness, air permeability, specific surface area, toluene adsorption amount, Raman peak intensity ratio (= Ia / Ig), and half width at half maximum of the Raman spectrum of the obtained knitted fabric (carrier made of fibrous activated carbon).
[0055]
Comparative Example 3
Using a phenol-based fiber having a single fiber fineness of 2.2 dtex and a thread-like fineness of 295 dtex, a milled knit was knitted with a 22-gauge double-sided circular knitting machine. This knitted fabric has a basis weight of 225 g / m. 2 , Thickness 1.65mm, apparent specific gravity 0.14g / cm 3 , Air permeability is 320cm 3 / Cm 2 -It was s. This knit is placed under an inert atmosphere (N 2 ), And the temperature was raised from room temperature to 820 ° C. (2 ° C./min) to carbonize the woven fabric. Further, when the temperature reached 820 ° C., the atmosphere was changed to an atmosphere containing 50 vol% of steam (remainder: N 2 ), And activated at the same temperature (820 ° C.) for 60 minutes. Table 1 shows the basis weight, thickness, air permeability, specific surface area, toluene adsorption amount, Raman peak intensity ratio (= Ia / Ig), and half width at half maximum of the Raman spectrum of the obtained knitted fabric (carrier made of fibrous activated carbon).
[0056]
Comparative Example 4
Novolak resin cured to a particle size of 250 to 550 μm 2 It was installed under an atmosphere, and after raising the temperature from room temperature to 890 ° C. (30 ° C./min), the atmosphere was changed to an atmosphere containing 50 vol% of steam (remainder: N 2 ) And an activation treatment was performed at the temperature (890 ° C.) for 30 minutes. A binder (polyamide binder, particle size: 200 to 700 μm) is mixed with the obtained activated carbon (the mixing ratio is activated carbon: binder = 2: 1), and the mixture is mixed with a polyester nonwoven fabric (30 g /
[0057]
How to measure hydrogen release and time to hydrogen release
Using a catalyst in which a metal catalyst (platinum) was supported on each carrier, the amount of hydrogen gas released and the time until the start of hydrogen release were examined. Note that the method of supporting platinum is as follows. 2 PtCl 4 After being immersed in an aqueous solution (5%) for 48 hours, dehydrated and dried, and further NaBH 4 It was immersed in an aqueous solution (5%). After immersion, it was pre-dried to remove water, and then reduced at 90 ° C. to obtain a platinum (5% by mass) supported catalyst. The resulting catalyst (10 cm 2 ) Was placed in a container 1 as shown in FIG. 1, and after filling with nitrogen, the container 1 was sealed. The container 1 was placed on the belt-shaped
[0058]
[Table 1]
In addition, the catalyst of the above embodiment of the present invention did not cause cracks or the like when filled in the apparatus, and was excellent in handleability. Further, during the test, even after the test, defects such as cracks did not occur, so that it had excellent handleability. On the other hand, the catalyst of Comparative Example 4 was inferior in flexibility and was poor in handleability, for example, cracking occurred when filling the inside of the device. After the test, the activated carbon was peeled off from the polyester-based nonwoven fabric and filled in the device.
[0060]
【The invention's effect】
As described above, the carrier of the present invention ensures sufficient strength while improving the effective surface area of the carrier, and is excellent in handleability. By specifying the crystal structure of carbon constituting the carrier, the activity of the catalyst can be improved. Therefore, when a catalyst comprising a metal supported on a carrier of the present invention is used, high catalytic performance can be exhibited, and the compound can be efficiently hydrogenated and dehydrogenated. Thus, the carrier of the present invention is suitable as a carrier for a catalyst for hydrogenation / dehydrogenation of an aromatic compound.
[0061]
Further, the hydrogen storage and release system using a catalyst in which a catalyst component is supported on a carrier according to the present invention can add or release hydrogen to a compound with high efficiency. Accordingly, the catalyst of the present invention in which a metal catalyst is supported on a carrier is capable of hydrogenating an aromatic compound in the presence of the catalyst to cause the compound to store hydrogen and, if necessary, converting the hydrogen storage product to the catalyst. Can be effectively used as a hydrogen storage and release system having a function of releasing hydrogen from the compound by causing a dehydrogenation reaction in the presence of hydrogen.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an apparatus used in an embodiment of the present invention.
[Explanation of symbols]
1 round bottom flask
2 Catalyst carrier
3 Electric heater
4 Cooling pipe
5 cooks
6 Hydrogen collection tube
7 Cooling pipe
8 Aromatic recovery section
Claims (6)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002193772A JP4161627B2 (en) | 2002-07-02 | 2002-07-02 | Carbon support for metal catalyst support |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002193772A JP4161627B2 (en) | 2002-07-02 | 2002-07-02 | Carbon support for metal catalyst support |
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| Publication Number | Publication Date |
|---|---|
| JP2004033891A true JP2004033891A (en) | 2004-02-05 |
| JP4161627B2 JP4161627B2 (en) | 2008-10-08 |
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| JP2002193772A Expired - Fee Related JP4161627B2 (en) | 2002-07-02 | 2002-07-02 | Carbon support for metal catalyst support |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024048410A1 (en) * | 2022-08-31 | 2024-03-07 | 東洋紡エムシー株式会社 | Activated carbon fiber non-woven fabric, activated carbon fiber non-woven fabric manufacturing method, element, organic solvent absorpbtion/desorption treatment device, organic solvent recovery system, organic solvent absorption/desorption treatment method, and organic solvent recovery method |
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2002
- 2002-07-02 JP JP2002193772A patent/JP4161627B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024048410A1 (en) * | 2022-08-31 | 2024-03-07 | 東洋紡エムシー株式会社 | Activated carbon fiber non-woven fabric, activated carbon fiber non-woven fabric manufacturing method, element, organic solvent absorpbtion/desorption treatment device, organic solvent recovery system, organic solvent absorption/desorption treatment method, and organic solvent recovery method |
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| Publication number | Publication date |
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| JP4161627B2 (en) | 2008-10-08 |
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