JP3616112B2 - Hydrocarbon adsorbent - Google Patents
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Description
【０００１】
【産業上の利用分野】
この発明は、自動車排気ガス浄化装置に使用される炭化水素（ＨＣ）吸着材に関する。
【０００２】
【従来の技術】
自動車の内燃機関から排出される排気ガス中のＨＣの触媒浄化能は、排気ガス温度の影響を強く受け、内燃機関の始動直後等排気ガス温度の低い時には触媒により浄化され難い。しかも始動直後には大量のＨＣが排出され、低温のＨＣがエミッション全体に占める割合が大きく、ＨＣの排出を抑制することが課題となっていた。このような状況下で提案された炭化水素吸着材としては例えば特開平２−１３５１２６号公報及び実開平２−３２８０８号公報に開示されているようなものがある。上記公開特許公報に記載されている吸着材はゼオライトをコートしたモノリス担体の一部に１種以上の触媒金属を担持してなるものである。
【０００３】
【発明が解決しようとする課題】
しかしながら、上記特開平２−１３５１２６号公報に開示されている炭化水素吸着材ではゼオライトとしてモルデナイト及び、Ｙ型ゼオライトを用いて炭化水素を吸着させ炭化水素を除去しているが炭化水素吸着材が必要なコールドスタート時には、ＨＣとともに多量の水分も同時に排出されるためモルデナイトやＹ型ゼオライトのみでは親水性のゼオライトであるためゼオライトがＨ２Ｏ を吸着してしまい、ＨＣを充分吸着できない。さらに、排ガス中に含まれる多量のＨＣを吸着するのには充分でない。
【０００４】
さらに実開平２−３２８０８号公報では、吸着材の前方に水分吸着材を配置しているため、後方に配置した吸着材が排ガスの圧力損失でガスが拡散せず充分吸着しないという問題があった。
【０００５】
【課題を解決するための手段】
この発明は、このような従来の問題点に着目してなされたもので、第１発明においては、細孔径、細孔形状などの結晶構造の異なるゼオライトを２種類以上混合する事を特徴とし、その１種類に水の影響を受けにくいＺＳＭ−５ゼオライトを用いることから低温時水分の多量に存在する条件下でも吸着でき、ＺＳＭ−５と他の種類のゼオライトを混合することで細孔が入り組み細孔構造が複雑化する事から多種の炭化水素を吸着する能力を有する。また、２種類以上のゼオライトをブレンドしていることから排ガスの吸着材内部への拡散性が良くなる。
【０００６】
また、第２発明においては、ゼオライトとして、シリカ／アルミナ比の異なる２種類以上のＺＳＭ−５ゼオライトを混合したスラリーをハニカム担体にコーティングしてなることを特徴とし、好ましくは水の多い低温時の吸着性能が優れている疏水性ゼオライトとしてＺＳＭ−５ゼオライト（シリカ／アルミナ比：ＳｉＯ２／Ａｌ２Ｏ３ ≧１００）と高温域での吸着性能が優れているＺＳＭ−５ゼオライト（ＳｉＯ２／Ａｌ２Ｏ３ ＜１００）の２種類を混合したゼオライトを用いる。このようにして水分の存在する条件下から高温時まで充分にＨＣ吸着能力を有し、幅広い温度域を利用できる。
【０００７】
【作用】
本発明においては内燃機関の排気ガス浄化のため、排気ガス浄化用触媒が現在使用されているが、排気ガスの有害成分のうちの炭化水素の排気ガス浄化能は排気ガスの温度の影響を強く受け、３００℃以上の温度にならないと貴金属触媒により浄化されないため、コールドスタート時には多量の炭化水素が排出されてしまう。このような、コールドスタート時に排出される炭化水素を除去するためには炭化水素を吸着する吸着材を用いることが必要となる。また、ゼオライト類は、均一な細孔を有する結晶性の多孔性物質であり、混合物中からその細孔入口を通過できる大きさの分子だけを選択的に、細孔内に吸着する特性を持ち、ゼオライトの種類によって有効細孔径は異なる。この特性により、コールドスタート時に排出される炭化水素を吸着し、触媒反応のおきない温度領域での排気ガス中のＨＣを低減する。
【０００８】
また、自動車の排気ガス中には多種の炭化水素が排出される。本発明者らはモルデナイト、Ｙ型ゼオライト、ＵＳＹ、β−ゼオライト、ＺＳＭ−５など細孔径、細孔形状など結晶構造の異なるゼオライト２種類以上を一定の割合で粉砕混合したスラリーをモノリス担体に塗布することで、多種の炭化水素を吸着することができ、炭化水素吸着能が向上することを見出した。またＨ２Ｏ の多い低温側ではあまり吸着能力のないＹ型、モルデナイトなどの親水性ゼオライトもＺＳＭ−５などの、水の影響を受けにくいゼオライトとブレンドすることにより、１種類のゼオライトの時より、細孔が複雑に入りこむため水の影響を受けにくく、さらに炭化水素の吸着能も向上する。また、１個のハニカム担体にコーティングして用いるので排気ガス拡散性がよく２種類以上のゼオライトの効果が有効に活用される。
【０００９】
また、ゼオライトのＨＣ吸着性能は、排気ガス温度により異なるが、本発明者らはＳｉＯ２／Ａｌ２Ｏ３ ≧１００、とＳｉＯ２／Ａｌ２Ｏ３ ＜１００のＰｄ／ＺＳＭ−５の２種類をブレンドすることにより、より吸着能が向上することを見いだした。水の多い低温側で優れた吸着能を持つ疏水性の高いＳｉＯ２／Ａｌ２Ｏ３ ≧１００のＺＳＭ−５とパラジウム（Ｐｄ）を効率よくイオン交換でき、交換金属をゼオライトの活性サイト中に安定な状態を保ち、高温側でも優れた吸着能を持つＳｉＯ２／Ａｌ２Ｏ３ ＜１００のＺＳＭ−５ゼオライトをそれぞれ一定比率でブレンドし、粉砕混合したスラリーをモノリス担体に塗布することでＨ２Ｏ の影響の異なる活性サイトがきれいに混合した状態でコーティングされ、ゼオライト構造中の入り組んだ位置にも活性点が存在するため、Ｈ２Ｏ の存在量が変化しても吸着能への影響が少なくなり、吸着能が向上し脱離しにくくなる。
【００１０】
本発明においてゼオライトの混合比は、一種のゼオライトにつき最低でも１０％以上を含む割合で混合するのが望ましく、混合したゼオライト中にうまく活性サイトをもたせる必要があるため、この効果のでやすいブレンド比＝１：３〜３：１の範囲で用いるのが望ましい。
【００１１】
実際の排気ガス組成中には分子径の異なる炭化水素分子が種々存在する為、排出ＨＣの全体量を減らすとともにオゾン生成率の高い炭化水素を吸着してＮＭＯＧ（ノン メタン オルガニック ガス）の低減効果を得るためには、細孔径の異なる３種のゼオライトがある程度の量以上含まれる必要がある。
【００１２】
本発明で使用される上記ゼオライトは、スラリーの調製のしやすさ、コーティング性などの点から平均粒子径が０．５ 〜３．０ μｍ程度の粉末を用いるのが好ましい。
【００１３】
【実施例】
この発明を次の実施例、比較例及び試験例により説明する。
実施例１
まずＰｄをイオン交換したＨ型ＺＳＭ−５ゼオライト（以下Ｐｄ／ＺＳＭ−５と記す）５０部、Ｈ型モルデナイトゼオライト５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ポットに仕込み、振動ミル装置で４０分間もしくは、ユニバーサルボールミル装置で６．５ 時間混合粉砕して、ウォッシュコートスラリーを製造した。コーティエライト製モノリス担体を吸引コート法で吸水処理した後、前記製造したスラリーを担体断面全体に均一に投入し吸引コート法で余分なスラリーを除去した。その後乾燥を行い、４００℃で約１時間仮焼成した。
これにより、Ｐｄ／ＺＳＭ−５とモルデナイトの混合ゼオライトが約９０ｇ／Ｌコート量で担体にコートされた。上記のウォッシュコート、乾燥及び焼成をさらに２回繰り返して合計約２００ｇ／Ｌの構造の異なる２種のゼオライト（Ｐｄ／ＺＳＭ−５とモルデナイト）を混合したものをコートし空気雰囲気中で６５０℃で４時間焼成を行い（吸着材−１）を得た。
【００１４】
実施例２
ブレンドするゼオライト粉末としてＨ型モルデナイトの代わりにＨ型ＵＳＹゼオライトを用いた以外は、実施例１の吸着材−１と同様にして、吸着材−２を調製した。
実施例１と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末５０部、Ｈ型ＵＳＹゼオライト粉末５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−２を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行った。
【００１５】
実施例３
ブレンドするゼオライト粉末としてＨ型モルデナイトの代わりにＨ型Ｙ型ゼオライトを用いた以外は、実施例１の吸着材−１と同様にして、吸着材−３を調製した。
実施例１と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末５０部、Ｈ型Ｙ型ゼオライト粉末５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−３を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行った。
【００１６】
実施例４
ブレンドするゼオライト粉末としてＰｄ／ＺＳＭ−５ゼオライトの代わりにＨ型ＺＳＭ−５を用いた以外は、実施例１の吸着材−１と同様にして、吸着材−４を調製した。
実施例１と同様にしてＨ型ＺＳＭ−５ゼオライト粉末５０部、Ｈ型モルデナイト粉末５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−４を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行ない、焼成は４００℃２時間行なった。
【００１７】
実施例５
ブレンドするゼオライト粉末としてＰｄ／ＺＳＭ−５ゼオライトの代わりにＨ型ＺＳＭ−５を用いた以外は、実施例２の吸着材−２と同様にして、吸着材−５を調製した。
実施例２と同様にしてＨ型ＺＳＭ−５ゼオライト粉末５０部、Ｈ型ＵＳＹゼオライト粉末５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−５を得た。
コーティングの塗布量、乾燥、焼成は吸着材−４と同様に行なった。
【００１８】
実施例６
ブレンドするゼオライト粉末としてＰｄ／ＺＳＭ−５ゼオライトの代わりにＨ型ＺＳＭ−５を用いた以外は、実施例３の吸着材−３と同様にして、吸着材−６を調製した。
実施例３と同様にしてＨ型ＺＳＭ−５ゼオライト粉末５０部、Ｙ型ゼオライト５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−６を得た。
コーティングの塗布量、乾燥、焼成は吸着材−４と同様に行なった。
【００１９】
実施例７
ブレンドするゼオライト粉末としてモルデナイトの代わりにＰｄ−モルデナイトを用いた以外は、実施例１の吸着材−１と同様にして、吸着材−７を調製した。
実施例１と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末５０部、Ｐｄ−モルデナイト５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−７を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００２０】
実施例８
ブレンドするゼオライト粉末としてモルデナイトの代わりにＰｄ−ＵＳＹゼオライトを用いた以外は、実施例１の吸着材−１と同様にして、吸着材−８を調製した。
実施例１と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末５０部、Ｐｄ−ＵＳＹゼオライト５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−８を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００２１】
実施例９
ブレンドするゼオライト粉末としてモルデナイトの代わりにＰｄ−Ｙ型ゼオライトを用いた以外は、実施例１の吸着材−１と同様にして、吸着材−９を調製した。
実施例１と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末５０部、Ｐｄ−Ｙ型ゼオライト５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−９を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００２２】
実施例１０
ブレンドするゼオライト粉末としてＰｄ／ＺＳＭ−５の代わりにＣｕでイオン交換したＺＳＭ−５（以下Ｃｕ／ＺＳＭ−５と記す）ゼオライトを用いた以外は、実施例１の吸着材−１と同様にして、吸着材−１０を調製した。
実施例１と同様にしてＣｕ／ＺＳＭ−５ゼオライト粉末５０部、Ｈ型モルデナイト粉末５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−１０を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行ない、焼成は４００℃で２時間行なった。
【００２３】
実施例１１
ブレンドするゼオライト粉末としてＰｄ／ＺＳＭ−５の代わりにＣｕ／ＺＳＭ−５ゼオライトを用いた以外は、実施例２の吸着材−２と同様にして、吸着材−１１を調製した。
実施例１と同様にしてＣｕ／ＺＳＭ−５ゼオライト粉末５０部、Ｈ型ＵＳＹゼオライト粉末５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−１１を得た。
コーティングの塗布量、乾燥、焼成は吸着材−４と同様に行なった。
【００２４】
実施例１２
ブレンドするゼオライト粉末としてＰｄ／ＺＳＭ−５の代わりにＣｕ／ＺＳＭ−５ゼオライトを用いた以外は、実施例３の吸着材−３と同様にして、吸着材−１２を調製した。
実施例２と同様にしてＣｕ／ＺＳＭ−５ゼオライト粉末５０部、Ｙ型ゼオライト粉末５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−１２を得た。
コーティングの塗布量、乾燥、焼成は吸着材−４と同様に行なった。
【００２５】
実施例１３
ブレンドするゼオライト粉末としてモルデナイトの代わりにＣｕ−モルデナイトを用いた以外は、実施例４の吸着材−４と同様にして、吸着材−１３を調製した。
実施例１と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末５０部、Ｃｕ−モルデナイト５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−１３を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００２６】
実施例１４
ブレンドするゼオライト粉末としてＵＳＹゼオライトの代わりにＣｕ−ＵＳＹゼオライトを用いた以外は、実施例２の吸着材−２と同様にして、吸着材−１４を調製した。
実施例２と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末５０部、Ｃｕ−ＵＳＹゼオライト５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−１４を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００２７】
実施例１５
ブレンドするゼオライト粉末としてＹゼオライトの代わりにＣｕ−Ｙゼオライトを用いた以外は、実施例３の吸着材−３と同様にして、吸着材−１５を調製した。
実施例３と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末５０部、Ｃｕ−Ｙゼオライト５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−１５を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００２８】
実施例１６
ブレンドするゼオライト粉末の混ぜ込み比を変えた以外は、実施例１の吸着材−１と同様にして、吸着材−１６を調製した。
実施例１と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末３０部、Ｈ型モルデナイト粉末６０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−１６を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００２９】
実施例１７
ブレンドするゼオライト粉末の混ぜ込み比を変えた以外は、実施例２の吸着材−２と同様にして、吸着材−１７を調製した。
実施例２と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末３０部、Ｈ型ＵＳＹゼオライト粉末６０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−１７を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００３０】
実施例１８
ブレンドするゼオライト粉末の混ぜ込み比を変えた以外は、実施例３の吸着材−３と同様にして、吸着材−１８を調製した。
実施例３と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末３０部、Ｈ型Ｙ型ゼオライト粉末６０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−１８を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００３１】
実施例１９
ブレンドするゼオライト粉末の混ぜ込み比を変えた以外は、実施例１の吸着材−１と同様にして、吸着材−１９を調製した。
実施例１と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末２５部、Ｈ型モルデナイトゼオライト粉末７５部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−１９を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００３２】
実施例２０
ブレンドするゼオライト粉末の混ぜ込み比を変えた以外は、実施例２の吸着材−２と同様にして、吸着材−２０を調製した。
実施例２と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末２５部、Ｈ型ＵＳＹゼオライト粉末７５部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−２０を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００３３】
実施例２１
ブレンドするゼオライト粉末の混ぜ込み比を変えた以外は、実施例３の吸着材−３と同様にして、吸着材−２１を調製した。
実施例３と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末２５部、Ｙ型ゼオライト粉末７５部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−２１を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００３４】
実施例２２
ブレンドするゼオライト粉末の混ぜ込み比を変えた以外は、実施例１の吸着材−１と同様にして、吸着材−２２を調製した。
実施例１と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末６０部、Ｈ型モルデナイト粉末３０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−２２を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００３５】
実施例２３
ブレンドするゼオライト粉末の混ぜ込み比を変えた以外は、実施例２の吸着材−２と同様にして、吸着材−２３を調製した。
実施例２と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末６０部、Ｈ型ＵＳＹゼオライト粉末３０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−２３を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００３６】
実施例２４
ブレンドするゼオライト粉末の混ぜ込み比を変えた以外は、実施例３の吸着材−３と同様にして、吸着材−２４を調製した。
実施例３と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末６０部、Ｈ型Ｙ型ゼオライト粉末３０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−２３を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００３７】
実施例２５
ブレンドするゼオライト粉末の混ぜ込み比を変えた以外は、実施例１の吸着材−１と同様にして、吸着材−２５を調製した。
実施例１と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末７５部、Ｈ型モルデナイトゼオライト粉末２５部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−２５を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００３８】
実施例２６
ブレンドするゼオライト粉末の混ぜ込み比を変えた以外は、実施例２の吸着材−２と同様にして、吸着材−２６を調製した。
実施例２と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末７５部、Ｈ型ＵＳＹゼオライト粉末２５部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−２６を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００３９】
実施例２７
ブレンドするゼオライト粉末の混ぜ込み比を変えた以外は、実施例３の吸着材−３と同様にして、吸着材−２７を調製した。
実施例３と同様にしてＰｄ／ＺＳＭ−５ゼオライト粉末７５部、Ｙ型ゼオライト粉末２５部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−２７を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００４０】
比較例１
実施例１と同様にしてＨ型ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末１００部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−２８を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００４１】
比較例２
実施例１と同様にしてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末１００部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−２９を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００４２】
実施例２８
Ｐｄ／ＺＳＭ−５を５０部、Ｈ型モルデナイトゼオライト２５部、Ｈ型ＵＳＹゼオライト２５部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−３０を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００４３】
実施例２９
Ｐｄ／ＺＳＭ−５を５０部、Ｈ型モルデナイトゼオライト２５部、Ｈ型βゼオライト２５部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−３１を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００４４】
実施例３０
Ｐｄ／ＺＳＭ−５をＨ型ＺＳＭ−５に変えた以外は、実施例２８の吸着材−３０と同様にして吸着材−３２を調製した。
実施例２８と同様にしてＨ型ＺＳＭ−５を５０部、Ｈ型モルデナイトゼオライト２５部、Ｈ型ＵＳＹゼオライト２５部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−３２を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００４５】
実施例３１
Ｐｄ／ＺＳＭ−５をＨ型ＺＳＭ−５に変えた以外は、実施例２９の吸着材−３１と同様にして吸着材−３３を調製した。
Ｈ型ＺＳＭ−５を５０部、Ｈ型モルデナイトゼオライト２５部、Ｈ型β−ゼオライト２５部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−３３を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００４６】
実施例３２
Ｐｄ／ＺＳＭ−５をＣｕ／ＺＳＭ−５に変えた以外は、実施例２８の吸着材−３０と同様にして吸着材−３４を調製した。
実施例２８と同様にしてＣｕ／ＺＳＭ−５を５０部、Ｈ型モルデナイトゼオライト２５部、Ｈ型ＵＳＹゼオライト２５部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−３４を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００４７】
実施例３３
Ｐｄ／ＺＳＭ−５をＣｕ／ＺＳＭ−５に変えた以外は、実施例２９の吸着材−３１と同様にして吸着材−３５を調製した。
Ｃｕ／ＺＳＭ−５を５０部、Ｈ型モルデナイトゼオライト２５部、Ｈ型β−ゼオライト２５部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−３５を得た。
コーティングの塗布量、乾燥、焼成は吸着材−１と同様に行なった。
【００４８】
試験例１
実施例１〜３３、比較例１，２の吸着材について車両（セドリック 排気量２０００ｃｃ）を用いて表１のＨＣ排出特性を示すＬＡ−４モードエミッションでのＨＣ吸着率を評価した結果を表２，３に示す。
【００４９】
【表１】
【表２】
【表３】
実施例３４
先ずＰｄをイオン交換したＨ型ＺＳＭ−５（ＳｉＯ２／Ａｌ２Ｏ３ ≧１００）ゼオライト（以下Ｐｄ／ＺＳＭ−５、Ｓｉ／Ａｌ≧１００と記す）５０部、Ｐｄをイオン交換したＨ型ＺＳＭ−５（ＳｉＯ２／Ａｌ２Ｏ３ ＜１００）ゼオライト（以下Ｐｄ／ＺＳＭ−５、Ｓｉ／Ａｌ＜１００と記す）５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ポットに仕込み、振動ミル装置で４０分間もしくは、ユニバーサルボールミル装置で６．５ 時間混合粉砕して、ウオッシュコートスラリーを製造した。コーディライト製モノリス担体を吸引コート法で吸水処理した後、前記で製造したスラリーを担体断面全体に均一に投入し吸引コート法で余分なスラリーを除去した。その後乾燥を行い４００℃で約１時間仮焼成した。
これにより、ＰｄのＨ型ＺＳＭ−５ゼオライト（Ｓｉ／Ａｌ≧１００と＜１００の混合物）が９０ｇ／Ｌのコート量で担体にコートされた上記のウオッシュコート、乾燥及び焼成をさらに２回繰り返して合計約２００ｇ／ＬのＳｉ／Ａｌ比の異なる２種のＰｄ／ＺＳＭ−５をブレンドさせたものをコートし空気雰囲気中で６５０℃で４時間焼成を行い吸着材−３６を得た。
【００５３】
実施例３５
ブレンドするゼオライト粉末としてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライトの代わりにＨ型ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）を用いた以外は、実施例３４の吸着材−３６と同様にして、吸着材−３５を調製した。
実施例３４と同様にしてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末５０部、Ｈ型ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライト粉末５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−３７を得た。
コーティングの塗布量、乾燥、焼成は吸着材−３６と同様に行なった。
【００５４】
実施例３６
ブレンドするゼオライト粉末としてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライトの代わりにＣｕでイオン交換したＺＳＭ−５（以下Ｃｕ／ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）を用い、Ｐｄ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライトの代わりにＣｕ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）を用いた以外は、実施例３４の吸着材−３６と同様にして、吸着材−３８を調製した。
実施例３４と同様にしてＣｕ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末５０部、Ｃｕ／ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライト粉末５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−３８を得た。
コーティングの塗布量、乾燥、焼成は吸着材−３６と同様に行なった。
【００５５】
実施例３７
ブレンドするゼオライト粉末としてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライトの代わりにＨ型ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）を用い、Ｐｄ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライトの代わりにＣｕでイオン交換したＺＳＭ−５（以下Ｃｕ／ＺＳＭ−５と記す）（Ｓｉ／Ａｌ＜１００）ゼオライトを用いた以外は、実施例３４の吸着材−３６と同様にして、吸着材−３９を調製した。
実施例３４と同様にしてＣｕ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末５０部、Ｈ型ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライト粉末５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−３９を得た。
コーティングの塗布量、乾燥、焼成は吸着材−３６と同様に行なった。
【００５６】
実施例３８
ブレンドするゼオライト粉末としてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライトの代わりにＨ型ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）を用い、Ｐｄ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライトの代わりにＨ型ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）を用いた以外は、実施例３４の吸着材−３６と同様にして、吸着材−４０を調製した。
実施例３４と同様にしてＨ型ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末５０部、Ｈ型ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライト粉末５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−３９を得た。
コーティングの塗布量、乾燥、焼成は吸着材−３６と同様に行なった。
【００５７】
実施例３９
ブレンドするゼオライト粉末としてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライトの代わりにＣｕでイオン交換したＺＳＭ−５（以下Ｃｕ／ＺＳＭ−５）（Ｓｉ／Ａｌ≧１００）を用いた以外は、実施例３４の吸着材−３６と同様にして、吸着材−４１を調製した。
実施例３４と同様にしてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末５０部、Ｃｕ／ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライト粉末５０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−３９を得た。
コーティングの塗布量、乾燥、焼成は吸着材−３６と同様に行なった。
【００５８】
実施例４０
ブレンドするゼオライト粉末の混ぜ込み比を変えた以外は、実施例３４の吸着材−３６と同様にして、吸着材−４２を調製した。
実施例３４と同様にしてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末３０部、Ｐｄ／ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライト粉末６０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−４２を得た。
コーティングの塗布量、乾燥、焼成は吸着材−３６と同様に行なった。
【００５９】
実施例４１
ブレンドする２種類のＳｉ／Ａｌ比の異なるＰｄ／ＺＳＭ−５ゼオライト粉末の混ぜ込み比を変えた以外は、実施例３５の吸着材−３７と同様にして、吸着材−４１を調製した。
実施例３５と同様にしてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末３０部、Ｈ型ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライト粉末６０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−４３を得た。
コーティングの塗布量、乾燥、焼成は吸着材−３４と同様に行なった。
【００６０】
実施例４２
ブレンドする２種類のＳｉ／Ａｌ比の異なるＰｄ／ＺＳＭ−５ゼオライト粉末の混ぜ込み比を変えた以外は、実施例３４の吸着材−３６と同様にして、吸着材−４４を調製した。
実施例３４と同様にしてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末２５部、Ｐｄ／ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライト粉末７５部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−４４を得た。
コーティングの塗布量、乾燥、焼成は吸着材−３６と同様に行なった。
【００６１】
実施例４３
ブレンドする２種類のＳｉ／Ａｌ比の異なるＰｄ／ＺＳＭ−５ゼオライト粉末の混ぜ込み比を変えた以外は、実施例３５の吸着材−３７と同様にして、吸着材−４５を調製した。
実施例３４と同様にしてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末２５部、Ｈ型ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライト粉末７５部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−４５を得た。
コーティングの塗布量、乾燥、焼成は吸着材−３７と同様に行なった。
【００６２】
実施例４４
ブレンドするゼオライト粉末の混ぜ込み比を変えた以外は、実施例３４の吸着材−３６と同様にして、吸着材−４６調製した。
実施例３４と同様にしてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末６０部、Ｈ型ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライト粉末３０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−４６を得た。
コーティングの塗布量、乾燥、焼成は吸着材−３６と同様に行なった。
【００６３】
実施例４５
ブレンドする２種類のＳｉ／Ａｌ比の異なるＰｄ／ＺＳＭ−５ゼオライト粉末の混ぜ込み比を変えた以外は、実施例３５の吸着材−３７と同様にして、吸着材−４７を調製した。
実施例３５と同様にしてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末６０部、Ｈ型ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライト粉末３０部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−４７を得た。
コーティングの塗布量、乾燥、焼成は吸着材−３６と同様に行なった。
【００６４】
実施例４６
ブレンドする２種類のＳｉ／Ａｌ比の異なるＰｄ／ＺＳＭ−５ゼオライト粉末の混ぜ込み比を変えた以外は、実施例３４の吸着材−３６と同様にして、吸着材−４８を調製した。
実施例３４と同様にしてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末２５部、Ｐｄ／ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライト粉末７５部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−４８を得た。
コーティングの塗布量、乾燥、焼成は吸着材−３６と同様に行なった。
【００６５】
実施例４７
ブレンドする２種類のＳｉ／Ａｌ比の異なるＰｄ／ＺＳＭ−５ゼオライト粉末の混ぜ込み比を変えた以外は、実施例３５の吸着材−３７と同様にして、吸着材−４９を調製した。
実施例３５と同様にしてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末２５部、Ｈ型ＺＳＭ−５（Ｓｉ／Ａｌ≧１００）ゼオライト粉末７５部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−４９を得た。
コーティングの塗布量、乾燥、焼成は吸着材−３６と同様に行なった。
【００６６】
比較例３
実施例３４と同様にしてＨ型ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末１００部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−５０を得た。
コーティングの塗布量、乾燥、焼成は吸着材−３６と同様に行なった。
【００６７】
比較例４
実施例３４と同様にしてＰｄ／ＺＳＭ−５（Ｓｉ／Ａｌ＜１００）ゼオライト粉末１００部、シリカゾル（固形分２０％）６５部、及び水６５部を磁性ボールミルに投入し混合粉砕したスラリーを吸引コート法でコーティングし、乾燥焼成してコート量が約２００ｇ／Ｌになるようにコーティングを行い吸着材−５１を得た。
コーティングの塗布量、乾燥、焼成は吸着材−３６と同様に行なった。
【００６８】
試験例２
実施例３４〜４７、比較例の３，４の吸着材について車両（セドリック 排気量２０００ｃｃ）を用いて試験例１の表１のＨＣ排出特性を示すＬＡ−４モードエミッションでのＨＣ吸着率を評価した結果を表４に示す。
【００６９】
【表４】
【発明の効果】
以上説明してきたように、本発明の第１発明の炭化水素吸着材では、ハニカム状のモノリス担体に細孔径、細孔形状など結晶構造の異なるゼオライト２種類以上を一定の割合で混合することで得られた吸着材をコーティングし、好ましくは炭化水素を吸着する吸着材としてＺＳＭ−５ゼオライト、モルデナイト、Ｙ型ゼオライト、ＵＳＹゼオライト、β−ゼオライトなどを用いることにより、水分が存在する条件下から充分に炭化水素の吸着能力を有し、排ガスから拡散性良く多種の炭化水素を吸着できる。
【００７１】
また第２発明の炭化水素吸着材では、ハニカム状のモノリス担体に、シリカ／アルミナ比の異なる２種類以上のＺＳＭ−５ゼオライトを混合したスラリーをコーディングし、好ましくは水の影響を除去できる疏水性のゼオライト（ＳｉＯ２／Ａｌ２Ｏ３ ≧１００）を用いた吸着材と高温時に脱離せず吸着することができるゼオライト（ＳｉＯ２／Ａｌ２Ｏ３ ＜１００）を用いた吸着材２種類以上を一定の割合で混合することで得られた吸着材をコーティングしたことにより、水分が存在する条件下から高温時まで脱離せず充分に炭化水素の吸着能力を有する。[0001]
[Industrial application fields]
The present invention relates to a hydrocarbon (HC) adsorbent used in an automobile exhaust gas purification device.
[0002]
[Prior art]
The catalytic purification ability of HC in the exhaust gas discharged from the internal combustion engine of an automobile is strongly affected by the exhaust gas temperature, and is difficult to be purified by the catalyst when the exhaust gas temperature is low, such as immediately after the start of the internal combustion engine. In addition, a large amount of HC is discharged immediately after starting, and the ratio of low-temperature HC to the entire emission is large, and it has been a problem to suppress the discharge of HC. As hydrocarbon adsorbents proposed under such circumstances, there are those disclosed in, for example, JP-A-2-135126 and JP-A-2-32808. The adsorbent described in the above-mentioned published patent publication is formed by supporting at least one catalyst metal on a part of a monolithic carrier coated with zeolite.
[0003]
[Problems to be solved by the invention]
However, in the hydrocarbon adsorbent disclosed in JP-A-2-135126, hydrocarbons are removed by adsorbing hydrocarbons using mordenite and Y-type zeolite as zeolite, but hydrocarbon adsorbents are necessary. During a cold start, a large amount of water is discharged at the same time as HC, so mordenite or Y-type zeolite alone is a hydrophilic zeolite, so the zeolite is H 2 O 2 is adsorbed and HC cannot be adsorbed sufficiently. Furthermore, it is not sufficient to adsorb a large amount of HC contained in the exhaust gas.
[0004]
Furthermore, in Japanese Utility Model Laid-Open No. 2-32808, since the moisture adsorbent is arranged in front of the adsorbent, there is a problem that the adsorbent arranged behind does not sufficiently adsorb because the gas does not diffuse due to the pressure loss of the exhaust gas. .
[0005]
[Means for Solving the Problems]
This invention was made paying attention to such a conventional problem, and in the first invention, it is characterized by mixing two or more kinds of zeolites having different crystal structures such as pore diameter and pore shape, One type of ZSM-5 zeolite, which is not easily affected by water, can be adsorbed even under conditions where a large amount of moisture is present at low temperatures. By mixing ZSM-5 with other types of zeolite, pores enter. It has the ability to adsorb various types of hydrocarbons because of its complicated pore structure. Further, since two or more types of zeolite are blended, the diffusibility of exhaust gas into the adsorbent is improved.
[0006]
In the second invention, the honeycomb carrier is coated with a slurry in which two or more kinds of ZSM-5 zeolites having different silica / alumina ratios are mixed as the zeolite. ZSM-5 zeolite (silica / alumina ratio: SiO 2 / Al 2 O 3 ≧ 100) and ZSM-5 zeolite (SiO 2 / Al 2 O 3 <100) Zeolite mixed with two types is used. Thus, it has a sufficient HC adsorption capacity from the condition where moisture exists to the time of high temperature, and a wide temperature range can be used.
[0007]
[Action]
In the present invention, an exhaust gas purification catalyst is currently used for exhaust gas purification of an internal combustion engine, but the exhaust gas purification ability of hydrocarbons among the harmful components of exhaust gas is strongly influenced by the temperature of the exhaust gas. However, since it is not purified by the noble metal catalyst unless the temperature reaches 300 ° C. or higher, a large amount of hydrocarbons are discharged at the cold start. In order to remove such hydrocarbons discharged at the cold start, it is necessary to use an adsorbent that adsorbs hydrocarbons. Zeolite is a crystalline porous material having uniform pores, and has the property of selectively adsorbing only molecules of a size that can pass through the pore inlet from the mixture. The effective pore size varies depending on the type of zeolite. Due to this characteristic, hydrocarbons discharged at the cold start are adsorbed, and HC in the exhaust gas is reduced in a temperature range where no catalytic reaction occurs.
[0008]
In addition, various hydrocarbons are discharged into the exhaust gas of automobiles. The present inventors applied a slurry obtained by pulverizing and mixing two or more kinds of zeolites having different crystal structures such as mordenite, Y-type zeolite, USY, β-zeolite, ZSM-5, etc. with different crystal structures such as pore diameter and pore shape to a monolith carrier. By doing so, it was found that a variety of hydrocarbons can be adsorbed and the hydrocarbon adsorption ability is improved. H 2 By blending hydrophilic zeolites such as Y-type and mordenite which are not very adsorbable on the low temperature side with a large amount of O 2, such as ZSM-5, which is less susceptible to water, the pores can be reduced compared to the case of one type of zeolite. Is difficult to be affected by water because it enters the complex, and the adsorption capacity of hydrocarbons is also improved. Further, since one honeycomb carrier is coated and used, the exhaust gas diffusibility is good and the effect of two or more kinds of zeolites is effectively utilized.
[0009]
Moreover, although the HC adsorption performance of zeolite varies depending on the exhaust gas temperature, the present inventors 2 / Al 2 O 3 ≧ 100, and SiO 2 / Al 2 O 3 It was found that the adsorption ability was further improved by blending two types of <100 Pd / ZSM-5. Highly hydrophobic SiO with excellent adsorption capacity on the low temperature side with a lot of water 2 / Al 2 O 3 ≧ 100 ZSM-5 and palladium (Pd) can be efficiently ion-exchanged, the exchange metal remains stable in the active site of the zeolite, and has excellent adsorption capacity even at high temperatures. 2 / Al 2 O 3 <100 ZSM-5 zeolites were each blended at a fixed ratio, and pulverized and mixed slurry was applied to a monolithic carrier. 2 Since active sites having different influences of O 2 are coated in a well-mixed state and active sites exist at intricate positions in the zeolite structure, 2 Even if the amount of O 2 is changed, the influence on the adsorption capacity is reduced, the adsorption capacity is improved, and the desorption is difficult.
[0010]
In the present invention, the mixing ratio of zeolite is desirably mixed at a ratio containing at least 10% per kind of zeolite, and it is necessary to have active sites well in the mixed zeolite. It is desirable to use in the range of 1: 3 to 3: 1.
[0011]
Since there are various hydrocarbon molecules with different molecular diameters in the actual exhaust gas composition, the total amount of exhaust HC is reduced and hydrocarbons with a high ozone production rate are adsorbed to reduce NMOG (non-methane organic gas). In order to obtain the effect, it is necessary that three kinds of zeolites having different pore diameters are contained in a certain amount or more.
[0012]
The zeolite used in the present invention is preferably a powder having an average particle diameter of about 0.5 to 3.0 μm from the viewpoint of ease of slurry preparation and coating properties.
[0013]
【Example】
The invention is illustrated by the following examples, comparative examples and test examples.
Example 1
First, 50 parts of H-type ZSM-5 zeolite ion-exchanged with Pd (hereinafter referred to as Pd / ZSM-5), 50 parts of H-type mordenite zeolite, 65 parts of silica sol (solid content 20%), and 65 parts of water are placed in a magnetic pot. The mixture was mixed and ground for 40 minutes using a vibration mill device or for 6.5 hours using a universal ball mill device to produce a washcoat slurry. The monolithic carrier made of Cortierite was subjected to water absorption treatment by the suction coating method, and then the prepared slurry was uniformly introduced into the entire cross section of the carrier, and excess slurry was removed by the suction coating method. Thereafter, drying was performed, and preliminary calcination was performed at 400 ° C. for about 1 hour.
Thereby, the mixed zeolite of Pd / ZSM-5 and mordenite was coated on the support at a coating amount of about 90 g / L. The above-mentioned wash coat, drying and firing were repeated two more times to coat a mixture of two types of zeolites (Pd / ZSM-5 and mordenite) having a total structure of about 200 g / L, and at 650 ° C. in an air atmosphere. Firing was performed for 4 hours to obtain (Adsorbent-1).
[0014]
Example 2
Adsorbent-2 was prepared in the same manner as Adsorbent-1 of Example 1 except that H-type USY zeolite was used instead of H-type mordenite as the zeolite powder to be blended.
In the same manner as in Example 1, 50 parts of Pd / ZSM-5 zeolite powder, 50 parts of H-type USY zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were charged into a magnetic ball mill and mixed and ground. Coating was performed by a suction coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L to obtain an adsorbent-2.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0015]
Example 3
Adsorbent-3 was prepared in the same manner as Adsorbent-1 of Example 1 except that H-type Y-type zeolite was used instead of H-type mordenite as the zeolite powder to be blended.
In the same manner as in Example 1, 50 parts of Pd / ZSM-5 zeolite powder, 50 parts of H-type Y zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were charged into a magnetic ball mill and mixed and ground. Was coated by a suction coating method, dried and fired, and coated so that the coating amount was about 200 g / L, to obtain an adsorbent-3.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0016]
Example 4
Adsorbent-4 was prepared in the same manner as Adsorbent-1 of Example 1 except that H-type ZSM-5 was used instead of Pd / ZSM-5 zeolite as the blended zeolite powder.
In the same manner as in Example 1, 50 parts of H-type ZSM-5 zeolite powder, 50 parts of H-type mordenite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a magnetic ball mill and mixed and ground slurry was sucked. Coating was performed by a coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L, thereby obtaining an adsorbent-4.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1, and firing was performed at 400 ° C. for 2 hours.
[0017]
Example 5
Adsorbent-5 was prepared in the same manner as Adsorbent-2 of Example 2 except that H-type ZSM-5 was used instead of Pd / ZSM-5 zeolite as the zeolite powder to be blended.
In the same manner as in Example 2, 50 parts of H-type ZSM-5 zeolite powder, 50 parts of H-type USY zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a magnetic ball mill and mixed and pulverized. Coating was performed by a suction coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L to obtain an adsorbent-5.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-4.
[0018]
Example 6
Adsorbent-6 was prepared in the same manner as Adsorbent-3 in Example 3 except that H-type ZSM-5 was used instead of Pd / ZSM-5 zeolite as the zeolite powder to be blended.
In the same manner as in Example 3, 50 parts of H-type ZSM-5 zeolite powder, 50 parts of Y-type zeolite, 65 parts of silica sol (20% solids), and 65 parts of water were put into a magnetic ball mill and mixed and pulverized slurry was suction coated. Coating was carried out by the method, followed by drying and baking, and coating was carried out so that the coating amount was about 200 g / L to obtain an adsorbent-6.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-4.
[0019]
Example 7
Adsorbent-7 was prepared in the same manner as Adsorbent-1 of Example 1 except that Pd-mordenite was used instead of mordenite as the zeolite powder to be blended.
In the same manner as in Example 1, 50 parts of Pd / ZSM-5 zeolite powder, 50 parts of Pd-mordenite, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a magnetic ball mill and mixed and pulverized slurry was suction coated. It was coated by the method, dried and baked, and coated so that the coating amount was about 200 g / L to obtain an adsorbent-7.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0020]
Example 8
Adsorbent-8 was prepared in the same manner as Adsorbent-1 of Example 1 except that Pd-USY zeolite was used instead of mordenite as the zeolite powder to be blended.
In the same manner as in Example 1, 50 parts of Pd / ZSM-5 zeolite powder, 50 parts of Pd-USY zeolite, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a magnetic ball mill and mixed and ground slurry was sucked. Coating was carried out by a coating method, followed by drying and baking, and coating was carried out so that the coating amount was about 200 g / L, whereby Adsorbent-8 was obtained.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0021]
Example 9
Adsorbent-9 was prepared in the same manner as Adsorbent-1 of Example 1 except that Pd-Y type zeolite was used instead of mordenite as the zeolite powder to be blended.
In the same manner as in Example 1, 50 parts of Pd / ZSM-5 zeolite powder, 50 parts of Pd-Y type zeolite, 65 parts of silica sol (solid content 20%), and 65 parts of water were charged into a magnetic ball mill and mixed and pulverized. Coating was performed by a suction coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L to obtain an adsorbent-9.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0022]
Example 10
Except for using ZSM-5 (hereinafter referred to as Cu / ZSM-5) zeolite ion-exchanged with Cu instead of Pd / ZSM-5 as the zeolite powder to be blended, the same procedure as in Adsorbent-1 of Example 1 was performed. Adsorbent-10 was prepared.
In the same manner as in Example 1, 50 parts of Cu / ZSM-5 zeolite powder, 50 parts of H-type mordenite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a magnetic ball mill and mixed and ground slurry was sucked. Coating was performed by a coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L, thereby obtaining an adsorbent-10.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1, and firing was performed at 400 ° C. for 2 hours.
[0023]
Example 11
Adsorbent-11 was prepared in the same manner as Adsorbent-2 of Example 2, except that Cu / ZSM-5 zeolite was used instead of Pd / ZSM-5 as the zeolite powder to be blended.
In the same manner as in Example 1, 50 parts of Cu / ZSM-5 zeolite powder, 50 parts of H-type USY zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were charged into a magnetic ball mill and mixed and ground. Coating was performed by a suction coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L to obtain an adsorbent-11.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-4.
[0024]
Example 12
Adsorbent-12 was prepared in the same manner as Adsorbent-3 of Example 3 except that Cu / ZSM-5 zeolite was used instead of Pd / ZSM-5 as the zeolite powder to be blended.
In the same manner as in Example 2, 50 parts of Cu / ZSM-5 zeolite powder, 50 parts of Y-type zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a magnetic ball mill and mixed and ground slurry was sucked. Coating was performed by a coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L, thereby obtaining an adsorbent-12.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-4.
[0025]
Example 13
Adsorbent-13 was prepared in the same manner as Adsorbent-4 of Example 4 except that Cu-mordenite was used instead of mordenite as the zeolite powder to be blended.
In the same manner as in Example 1, 50 parts of Pd / ZSM-5 zeolite powder, 50 parts of Cu-mordenite, 65 parts of silica sol (20% solids), and 65 parts of water were put into a magnetic ball mill, and mixed and ground slurry was suction coated. It was coated by the method, dried and baked, and coated so that the coating amount was about 200 g / L to obtain an adsorbent-13.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0026]
Example 14
Adsorbent-14 was prepared in the same manner as Adsorbent-2 of Example 2 except that Cu-USY zeolite was used instead of USY zeolite as the zeolite powder to be blended.
In the same manner as in Example 2, 50 parts of Pd / ZSM-5 zeolite powder, 50 parts of Cu-USY zeolite, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a magnetic ball mill and mixed and ground slurry was sucked. Coating was performed by a coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L, thereby obtaining an adsorbent-14.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0027]
Example 15
Adsorbent-15 was prepared in the same manner as Adsorbent-3 of Example 3 except that Cu-Y zeolite was used instead of Y zeolite as the zeolite powder to be blended.
In the same manner as in Example 3, 50 parts of Pd / ZSM-5 zeolite powder, 50 parts of Cu-Y zeolite, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a magnetic ball mill and mixed and ground slurry was sucked. Coating was performed by a coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L, thereby obtaining an adsorbent-15.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0028]
Example 16
Adsorbent-16 was prepared in the same manner as Adsorbent-1 of Example 1 except that the mixing ratio of the zeolite powder to be blended was changed.
In the same manner as in Example 1, 30 parts of Pd / ZSM-5 zeolite powder, 60 parts of H-type mordenite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a magnetic ball mill and mixed and ground slurry was sucked. Coating was carried out by a coating method, followed by drying and baking, and coating was carried out so that the coating amount was about 200 g / L, whereby Adsorbent-16 was obtained.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0029]
Example 17
Adsorbent-17 was prepared in the same manner as Adsorbent-2 of Example 2 except that the mixing ratio of the zeolite powder to be blended was changed.
In the same manner as in Example 2, 30 parts of Pd / ZSM-5 zeolite powder, 60 parts of H-type USY zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were charged into a magnetic ball mill and mixed and ground. Coating was performed by a suction coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L to obtain an adsorbent-17.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0030]
Example 18
Adsorbent-18 was prepared in the same manner as Adsorbent-3 of Example 3 except that the mixing ratio of the zeolite powder to be blended was changed.
In the same manner as in Example 3, 30 parts of Pd / ZSM-5 zeolite powder, 60 parts of H-type Y zeolite powder, 65 parts of silica sol (20% solids), and 65 parts of water were charged into a magnetic ball mill and mixed and ground. Was coated by a suction coating method, dried and fired, and coated so that the coating amount was about 200 g / L, to obtain an adsorbent-18.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0031]
Example 19
Adsorbent-19 was prepared in the same manner as Adsorbent-1 of Example 1 except that the mixing ratio of the zeolite powder to be blended was changed.
In the same manner as in Example 1, 25 parts of Pd / ZSM-5 zeolite powder, 75 parts of H-type mordenite zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were charged into a magnetic ball mill and mixed and ground. Coating was performed by a suction coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L to obtain an adsorbent-19.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0032]
Example 20
Adsorbent-20 was prepared in the same manner as Adsorbent-2 of Example 2 except that the mixing ratio of the zeolite powder to be blended was changed.
In the same manner as in Example 2, 25 parts of Pd / ZSM-5 zeolite powder, 75 parts of H-type USY zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were charged into a magnetic ball mill and mixed and ground. Coating was performed by a suction coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L, thereby obtaining an adsorbent-20.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0033]
Example 21
Adsorbent-21 was prepared in the same manner as Adsorbent-3 of Example 3 except that the mixing ratio of the zeolite powder to be blended was changed.
In the same manner as in Example 3, 25 parts of Pd / ZSM-5 zeolite powder, 75 parts of Y-type zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a magnetic ball mill, and the mixed and pulverized slurry was sucked. Coating was performed by a coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L, thereby obtaining an adsorbent-21.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0034]
Example 22
Adsorbent-22 was prepared in the same manner as Adsorbent-1 of Example 1 except that the mixing ratio of the zeolite powder to be blended was changed.
In the same manner as in Example 1, 60 parts of Pd / ZSM-5 zeolite powder, 30 parts of H-type mordenite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a magnetic ball mill and mixed and ground slurry was sucked. Coating was performed by a coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L, thereby obtaining an adsorbent-22.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0035]
Example 23
Adsorbent-23 was prepared in the same manner as Adsorbent-2 of Example 2 except that the mixing ratio of the zeolite powder to be blended was changed.
In the same manner as in Example 2, 60 parts of Pd / ZSM-5 zeolite powder, 30 parts of H-type USY zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were charged into a magnetic ball mill and mixed and ground. Coating was performed by a suction coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L to obtain an adsorbent-23.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0036]
Example 24
Adsorbent-24 was prepared in the same manner as Adsorbent-3 of Example 3 except that the mixing ratio of the zeolite powder to be blended was changed.
In the same manner as in Example 3, 60 parts of Pd / ZSM-5 zeolite powder, 30 parts of H-type Y zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were charged into a magnetic ball mill and mixed and ground. Was coated by a suction coating method, dried and baked, and coated so that the coating amount was about 200 g / L to obtain an adsorbent-23.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0037]
Example 25
Adsorbent-25 was prepared in the same manner as Adsorbent-1 of Example 1 except that the mixing ratio of the zeolite powder to be blended was changed.
In the same manner as in Example 1, 75 parts of Pd / ZSM-5 zeolite powder, 25 parts of H-type mordenite zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were charged into a magnetic ball mill and mixed and ground. Coating was performed by a suction coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L to obtain an adsorbent-25.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0038]
Example 26
Adsorbent-26 was prepared in the same manner as Adsorbent-2 of Example 2 except that the mixing ratio of the zeolite powder to be blended was changed.
In the same manner as in Example 2, 75 parts of Pd / ZSM-5 zeolite powder, 25 parts of H-type USY zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were charged into a magnetic ball mill and mixed and ground. Coating was performed by a suction coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L to obtain an adsorbent-26.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0039]
Example 27
Adsorbent-27 was prepared in the same manner as Adsorbent-3 of Example 3 except that the mixing ratio of the zeolite powder to be blended was changed.
In the same manner as in Example 3, 75 parts of Pd / ZSM-5 zeolite powder, 25 parts of Y-type zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a magnetic ball mill and mixed and ground slurry was sucked. Coating was carried out by a coating method, followed by drying and baking, and coating was carried out so that the coating amount was about 200 g / L to obtain an adsorbent-27.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0040]
Comparative Example 1
In the same manner as in Example 1, 100 parts of H-type ZSM-5 (Si / Al <100) zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a magnetic ball mill and mixed and ground slurry was sucked. Coating was performed by a coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L, to obtain an adsorbent-28.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0041]
Comparative Example 2
In the same manner as in Example 1, 100 parts of Pd / ZSM-5 (Si / Al <100) zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a magnetic ball mill, and the mixed and pulverized slurry was sucked. Coating was performed by a coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L, to obtain an adsorbent-29.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0042]
Example 28
50 parts of Pd / ZSM-5, 25 parts of H-type mordenite zeolite, 25 parts of H-type USY zeolite, 65 parts of silica sol (solid content 20%), and 65 parts of water are put into a magnetic ball mill and sucked and mixed with a slurry. It was coated by the method, dried and fired, and coated so that the coating amount was about 200 g / L, to obtain an adsorbent-30.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0043]
Example 29
50 parts of Pd / ZSM-5, 25 parts of H-type mordenite zeolite, 25 parts of H-type β zeolite, 65 parts of silica sol (solid content 20%), and 65 parts of water are put into a magnetic ball mill and mixed and pulverized slurry is suction-coated. Coating was performed by the method, followed by drying and baking, and coating was performed so that the coating amount was about 200 g / L to obtain an adsorbent-31.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0044]
Example 30
Adsorbent-32 was prepared in the same manner as Adsorbent-30 of Example 28 except that Pd / ZSM-5 was changed to H-type ZSM-5.
In the same manner as in Example 28, 50 parts of H-type ZSM-5, 25 parts of H-type mordenite zeolite, 25 parts of H-type USY zeolite, 65 parts of silica sol (20% solids), and 65 parts of water were charged into a magnetic ball mill. The mixed and pulverized slurry was coated by a suction coating method, dried and fired, and coated so that the coating amount was about 200 g / L to obtain an adsorbent-32.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0045]
Example 31
Adsorbent-33 was prepared in the same manner as Adsorbent-31 of Example 29 except that Pd / ZSM-5 was changed to H-type ZSM-5.
50 parts of H-type ZSM-5, 25 parts of H-type mordenite zeolite, 25 parts of H-type β-zeolite, 65 parts of silica sol (20% solids), and 65 parts of water are put into a magnetic ball mill and mixed and ground slurry is sucked Coating was performed by a coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L, to obtain an adsorbent-33.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0046]
Example 32
Adsorbent-34 was prepared in the same manner as Adsorbent-30 of Example 28 except that Pd / ZSM-5 was changed to Cu / ZSM-5.
In the same manner as in Example 28, 50 parts of Cu / ZSM-5, 25 parts of H-type mordenite zeolite, 25 parts of H-type USY zeolite, 65 parts of silica sol (solid content 20%), and 65 parts of water were charged into a magnetic ball mill. The mixed and crushed slurry was coated by a suction coating method, dried and fired, and coated so that the coating amount was about 200 g / L, to obtain an adsorbent-34.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0047]
Example 33
Adsorbent-35 was prepared in the same manner as Adsorbent-31 of Example 29 except that Pd / ZSM-5 was changed to Cu / ZSM-5.
50 parts of Cu / ZSM-5, 25 parts of H-type mordenite zeolite, 25 parts of H-type β-zeolite, 65 parts of silica sol (solid content 20%), and 65 parts of water are put into a magnetic ball mill and sucked by mixing and grinding the slurry. Coating was performed by a coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L, to obtain an adsorbent-35.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-1.
[0048]
Test example 1
Table 2 shows the results of evaluating the HC adsorption rate in LA-4 mode emission showing the HC emission characteristics of Table 1 using the vehicle (Cedric displacement 2000 cc) for the adsorbents of Examples 1 to 33 and Comparative Examples 1 and 2. , 3.
[0049]
[Table 1]
[Table 2]
[Table 3]
Example 34
First, Pd is ion-exchanged H-type ZSM-5 (SiO 2 / Al 2 O 3 ≧ 100) 50 parts of zeolite (hereinafter referred to as Pd / ZSM-5, Si / Al ≧ 100), H-type ZSM-5 (SiO 2) ion-exchanged with Pd 2 / Al 2 O 3 <100) Zeolite (hereinafter referred to as Pd / ZSM-5, Si / Al <100) 50 parts, silica sol (solid content 20%) 65 parts, and water 65 parts are charged in a magnetic pot and shaken for 40 minutes or Then, it was mixed and pulverized in a universal ball mill apparatus for 6.5 hours to produce a washcoat slurry. After the cordierite monolith carrier was subjected to water absorption treatment by the suction coating method, the slurry produced above was uniformly introduced to the entire cross section of the carrier, and excess slurry was removed by the suction coating method. Thereafter, drying was performed, and preliminary calcination was performed at 400 ° C. for about 1 hour.
As a result, the above-described washcoat in which the carrier was coated with Pd H-type ZSM-5 zeolite (mixture of Si / Al ≧ 100 and <100) at a coating amount of 90 g / L, drying and firing were repeated twice more. A blend of two types of Pd / ZSM-5 having a different Si / Al ratio of about 200 g / L was coated and baked at 650 ° C. for 4 hours in an air atmosphere to obtain an adsorbent-36.
[0053]
Example 35
The same as adsorbent-36 of Example 34, except that H-type ZSM-5 (Si / Al ≧ 100) was used instead of Pd / ZSM-5 (Si / Al ≧ 100) zeolite as the zeolite powder to be blended. Thus, adsorbent-35 was prepared.
As in Example 34, 50 parts of Pd / ZSM-5 (Si / Al <100) zeolite powder, 50 parts of H-type ZSM-5 (Si / Al ≧ 100) zeolite powder, 65 parts of silica sol (solid content 20%) Then, 65 parts of water was put into a magnetic ball mill, and the slurry obtained by mixing and pulverizing was coated by a suction coating method, dried and baked, and coated so that the coating amount was about 200 g / L to obtain an adsorbent-37.
The amount of coating applied, drying and firing were performed in the same manner as the adsorbent-36.
[0054]
Example 36
ZSM-5 ion exchanged with Cu instead of Pd / ZSM-5 (Si / Al ≧ 100) zeolite (hereinafter referred to as Cu / ZSM-5 (Si / Al ≧ 100)) was used as the zeolite powder to be blended, and Pd / ZSM− Adsorbent-38 was prepared in the same manner as Adsorbent-36 of Example 34 except that Cu / ZSM-5 (Si / Al <100) was used instead of 5 (Si / Al <100) zeolite. .
As in Example 34, 50 parts of Cu / ZSM-5 (Si / Al <100) zeolite powder, 50 parts of Cu / ZSM-5 (Si / Al ≧ 100) zeolite powder, 65 parts of silica sol (solid content 20%) Then, 65 parts of water was put into a magnetic ball mill, and the slurry obtained by mixing and pulverizing was coated by a suction coating method, dried and fired, and coated so that the coating amount was about 200 g / L to obtain an adsorbent-38.
The amount of coating applied, drying and firing were performed in the same manner as the adsorbent-36.
[0055]
Example 37
Instead of Pd / ZSM-5 (Si / Al ≧ 100) zeolite, H-type ZSM-5 (Si / Al ≧ 100) is used as the zeolite powder to be blended, and Pd / ZSM-5 (Si / Al <100) zeolite is used. Instead of ZSM-5 (hereinafter referred to as Cu / ZSM-5) (Si / Al <100) zeolite ion-exchanged with Cu, adsorbent − was obtained in the same manner as adsorbent −36 of Example 34. 39 was prepared.
As in Example 34, 50 parts of Cu / ZSM-5 (Si / Al <100) zeolite powder, 50 parts of H-type ZSM-5 (Si / Al ≧ 100) zeolite powder, 65 parts of silica sol (solid content 20%) Then, 65 parts of water was put into a magnetic ball mill, and the slurry obtained by mixing and pulverizing was coated by a suction coating method, dried and fired, and coated so that the coating amount was about 200 g / L to obtain an adsorbent-39.
The amount of coating applied, drying and firing were performed in the same manner as the adsorbent-36.
[0056]
Example 38
Instead of Pd / ZSM-5 (Si / Al ≧ 100) zeolite, H-type ZSM-5 (Si / Al ≧ 100) is used as the zeolite powder to be blended, and Pd / ZSM-5 (Si / Al <100) zeolite is used. Instead, Adsorbent-40 was prepared in the same manner as Adsorbent-36 of Example 34 except that H-type ZSM-5 (Si / Al <100) was used.
As in Example 34, 50 parts of H-type ZSM-5 (Si / Al <100) zeolite powder, 50 parts of H-type ZSM-5 (Si / Al ≧ 100) zeolite powder, 65 parts of silica sol (solid content 20%) Then, 65 parts of water was put into a magnetic ball mill, and the slurry obtained by mixing and pulverizing was coated by a suction coating method, dried and fired, and coated so that the coating amount was about 200 g / L to obtain an adsorbent-39.
The amount of coating applied, drying and firing were performed in the same manner as the adsorbent-36.
[0057]
Example 39
ZSM-5 ion exchanged with Cu instead of Pd / ZSM-5 (Si / Al ≧ 100) zeolite (hereinafter Cu / ZSM-5) (Si / Al ≧ 100) was used as the zeolite powder to be blended, Adsorbent-41 was prepared in the same manner as Adsorbent-36 of Example 34.
50 parts Pd / ZSM-5 (Si / Al <100) zeolite powder, 50 parts Cu / ZSM-5 (Si / Al ≧ 100) zeolite powder, 65 parts silica sol (solid content 20%) in the same manner as in Example 34 Then, 65 parts of water was put into a magnetic ball mill, and the slurry obtained by mixing and pulverizing was coated by a suction coating method, dried and fired, and coated so that the coating amount was about 200 g / L to obtain an adsorbent-39.
The amount of coating applied, drying and firing were performed in the same manner as the adsorbent-36.
[0058]
Example 40
An adsorbent-42 was prepared in the same manner as the adsorbent-36 of Example 34 except that the mixing ratio of the zeolite powder to be blended was changed.
In the same manner as in Example 34, 30 parts of Pd / ZSM-5 (Si / Al <100) zeolite powder, 60 parts of Pd / ZSM-5 (Si / Al ≧ 100) zeolite powder, 65 parts of silica sol (solid content 20%) Then, 65 parts of water was put into a magnetic ball mill, and the slurry obtained by mixing and pulverizing was coated by a suction coating method, dried and fired, and coated so that the coating amount was about 200 g / L to obtain an adsorbent-42.
The amount of coating applied, drying and firing were performed in the same manner as the adsorbent-36.
[0059]
Example 41
Adsorbent-41 was prepared in the same manner as Adsorbent-37 of Example 35 except that the mixing ratio of the two types of Pd / ZSM-5 zeolite powders with different Si / Al ratios to be blended was changed.
In the same manner as in Example 35, Pd / ZSM-5 (Si / Al <100) zeolite powder 30 parts, H-type ZSM-5 (Si / Al ≧ 100) zeolite powder 60 parts, silica sol (solid content 20%) 65 parts Then, 65 parts of water was put into a magnetic ball mill, and the slurry obtained by mixing and pulverizing was coated by a suction coating method, dried and baked, and coated so that the coating amount was about 200 g / L to obtain an adsorbent-43.
The amount of coating applied, drying, and firing were performed in the same manner as the adsorbent-34.
[0060]
Example 42
An adsorbent-44 was prepared in the same manner as the adsorbent-36 of Example 34 except that the mixing ratio of the two types of Pd / ZSM-5 zeolite powders with different Si / Al ratios to be blended was changed.
In the same manner as in Example 34, 25 parts of Pd / ZSM-5 (Si / Al <100) zeolite powder, 75 parts of Pd / ZSM-5 (Si / Al ≧ 100) zeolite powder, 65 parts of silica sol (solid content 20%) Then, 65 parts of water was put into a magnetic ball mill, and the slurry obtained by mixing and pulverizing was coated by a suction coating method, dried and baked, and coated so that the coating amount was about 200 g / L to obtain an adsorbent-44.
The amount of coating applied, drying and firing were performed in the same manner as the adsorbent-36.
[0061]
Example 43
An adsorbent-45 was prepared in the same manner as the adsorbent-37 of Example 35 except that the mixing ratio of the two types of Pd / ZSM-5 zeolite powders with different Si / Al ratios to be blended was changed.
In the same manner as in Example 34, Pd / ZSM-5 (Si / Al <100) zeolite powder 25 parts, H-type ZSM-5 (Si / Al ≧ 100) zeolite powder 75 parts, silica sol (solid content 20%) 65 parts Then, 65 parts of water was added to a magnetic ball mill, and the slurry obtained by mixing and pulverizing was coated by a suction coating method, dried and fired, and coated so that the coating amount was about 200 g / L to obtain an adsorbent-45.
The amount of coating applied, drying, and firing were performed in the same manner as adsorbent-37.
[0062]
Example 44
An adsorbent-46 was prepared in the same manner as the adsorbent-36 of Example 34 except that the mixing ratio of the zeolite powder to be blended was changed.
In the same manner as in Example 34, 60 parts of Pd / ZSM-5 (Si / Al <100) zeolite powder, 30 parts of H-type ZSM-5 (Si / Al ≧ 100) zeolite powder, 65 parts of silica sol (solid content 20%) Then, 65 parts of water was put into a magnetic ball mill, and the slurry obtained by mixing and pulverizing was coated by a suction coating method, dried and baked, and coated so that the coating amount was about 200 g / L to obtain an adsorbent-46.
The amount of coating applied, drying and firing were performed in the same manner as the adsorbent-36.
[0063]
Example 45
Adsorbent-47 was prepared in the same manner as Adsorbent-37 of Example 35 except that the mixing ratio of the two types of Pd / ZSM-5 zeolite powders with different Si / Al ratios to be blended was changed.
In the same manner as in Example 35, 60 parts of Pd / ZSM-5 (Si / Al <100) zeolite powder, 30 parts of H-type ZSM-5 (Si / Al ≧ 100) zeolite powder, 65 parts of silica sol (solid content 20%) Then, 65 parts of water was put into a magnetic ball mill, and the slurry obtained by mixing and pulverizing was coated by a suction coating method, dried and baked, and coated so that the coating amount was about 200 g / L to obtain an adsorbent-47.
The amount of coating applied, drying and firing were performed in the same manner as the adsorbent-36.
[0064]
Example 46
Adsorbent-48 was prepared in the same manner as Adsorbent-36 of Example 34 except that the mixing ratio of the two types of Pd / ZSM-5 zeolite powders with different Si / Al ratios to be blended was changed.
In the same manner as in Example 34, 25 parts of Pd / ZSM-5 (Si / Al <100) zeolite powder, 75 parts of Pd / ZSM-5 (Si / Al ≧ 100) zeolite powder, 65 parts of silica sol (solid content 20%) Then, 65 parts of water was put into a magnetic ball mill, and the slurry obtained by mixing and pulverizing was coated by a suction coating method, dried and baked, and coated so that the coating amount became about 200 g / L to obtain an adsorbent-48.
The amount of coating applied, drying and firing were performed in the same manner as the adsorbent-36.
[0065]
Example 47
Adsorbent-49 was prepared in the same manner as Adsorbent-37 of Example 35, except that the mixing ratio of the two types of Pd / ZSM-5 zeolite powders with different Si / Al ratios to be blended was changed.
In the same manner as in Example 35, 25 parts of Pd / ZSM-5 (Si / Al <100) zeolite powder, 75 parts of H-type ZSM-5 (Si / Al ≧ 100) zeolite powder, 65 parts of silica sol (solid content 20%) Then, 65 parts of water was added to a magnetic ball mill, and the slurry obtained by mixing and pulverizing was coated by a suction coating method, dried and fired, and coated so that the coating amount became about 200 g / L to obtain an adsorbent-49.
The amount of coating applied, drying and firing were performed in the same manner as the adsorbent-36.
[0066]
Comparative Example 3
In the same manner as in Example 34, 100 parts of H-type ZSM-5 (Si / Al <100) zeolite powder, 65 parts of silica sol (20% solids), and 65 parts of water were put into a magnetic ball mill and mixed and pulverized slurry was sucked. Coating was carried out by a coating method, followed by drying and baking, and coating was carried out so that the coating amount was about 200 g / L to obtain an adsorbent-50.
The amount of coating applied, drying and firing were performed in the same manner as the adsorbent-36.
[0067]
Comparative Example 4
In the same manner as in Example 34, 100 parts of Pd / ZSM-5 (Si / Al <100) zeolite powder, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a magnetic ball mill, and the mixed and pulverized slurry was sucked. Coating was performed by a coating method, followed by drying and baking, and coating was performed so that the coating amount became about 200 g / L, to obtain an adsorbent-51.
The amount of coating applied, drying, and baking were performed in the same manner as the adsorbent-36.
[0068]
Test example 2
Evaluation of HC adsorption rate in LA-4 mode emission showing the HC emission characteristics in Table 1 of Test Example 1 using vehicles (Cedric displacement 2000 cc) for the adsorbents of Examples 34 to 47 and Comparative Examples 3 and 4 Table 4 shows the results.
[0069]
[Table 4]
【The invention's effect】
As described above, in the hydrocarbon adsorbent according to the first invention of the present invention, two or more kinds of zeolites having different crystal structures such as pore diameter and pore shape are mixed with a honeycomb monolith support at a certain ratio. By coating the obtained adsorbent, preferably using ZSM-5 zeolite, mordenite, Y-type zeolite, USY zeolite, β-zeolite, etc. as the adsorbent for adsorbing hydrocarbons, it is sufficient from the condition where moisture exists. Has the ability to adsorb hydrocarbons and can adsorb various hydrocarbons from exhaust gas with good diffusivity.
[0071]
Further, in the hydrocarbon adsorbent of the second invention, a slurry in which two or more kinds of ZSM-5 zeolites having different silica / alumina ratios are mixed with a honeycomb-shaped monolith support is coded, and the hydrophobicity which can preferably remove the influence of water Zeolite (SiO 2 / Al 2 O 3 ≧ 100) and adsorbents that can be adsorbed without desorption at high temperatures (SiO 2) 2 / Al 2 O 3 <100) By adsorbing the adsorbent obtained by mixing two or more adsorbents at a certain ratio, sufficient adsorption of hydrocarbons without desorption from the condition of moisture to high temperature Have the ability.
Claims (5)
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34890692A JP3616112B2 (en) | 1992-12-28 | 1992-12-28 | Hydrocarbon adsorbent |
| US08/147,267 US5407880A (en) | 1992-11-09 | 1993-11-05 | Catalysts for adsorption of hydrocarbons |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34890692A JP3616112B2 (en) | 1992-12-28 | 1992-12-28 | Hydrocarbon adsorbent |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06198164A JPH06198164A (en) | 1994-07-19 |
| JP3616112B2 true JP3616112B2 (en) | 2005-02-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP34890692A Expired - Fee Related JP3616112B2 (en) | 1992-11-09 | 1992-12-28 | Hydrocarbon adsorbent |
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| Country | Link |
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| JP (1) | JP3616112B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3417309B2 (en) * | 1997-10-28 | 2003-06-16 | トヨタ自動車株式会社 | Hydrocarbon adsorbent |
| EP1129774A4 (en) * | 1998-10-28 | 2003-04-16 | Toyota Motor Co Ltd | HYDROCARBON ADSORBENT AGENT AND EXHAUST GAS PURIFICATION CATALYST |
| US7981834B2 (en) | 2006-03-16 | 2011-07-19 | Ict Co., Ltd. | Adsorbent for hydrocarbons, catalyst for exhaust gas purification and method for exhaust gas purification |
| JP4648914B2 (en) * | 2006-03-16 | 2011-03-09 | 株式会社アイシーティー | Hydrocarbon adsorbent, exhaust gas purification catalyst and exhaust gas purification method |
| KR102085652B1 (en) * | 2017-12-29 | 2020-03-06 | 현대자동차 주식회사 | Hydrocarbon Trap Comprising Metal-impregnated Zeolite Particles Having Regular Mesopores and Method of Preparing the Same |
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1992
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| JPH06198164A (en) | 1994-07-19 |
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