JP2004290753A - Heat-resistant denitrification catalyst - Google Patents
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【０００１】
【発明の属する技術分野】
本発明は、耐熱性脱硝触媒に関し、詳しくは、バナジウム系脱硝触媒であって、５００℃以上の高温の排ガスが通過した際に起こり得るＶ２Ｏ５のガス中への飛散による性能低下や環境汚染を抑制した耐熱性脱硝触媒に関する。
【０００２】
【従来の技術】
バナジウム系脱硝触媒による排ガス中の窒素酸化物の除去方法（例えば特許文献１参照）は、各種の分野で実用化されている。
【０００３】
【特許文献１】
特開昭５０−５１９６６号公報
【０００４】
近年、火力発電などのボイラーに使用される燃料の質は、費用節減のため、低下している。そのため、燃え残る有機物量が増大している。通常、有機物はバナジウム系脱硝触媒層を通過する際、３５０℃程度の温度であれば燃焼反応が起こり、無害化される。ところが、低品位の燃料の使用により、ボイラーで燃え残る有機物量が増大した結果、脱硝触媒層での燃焼反応による発熱量が膨大になり、触媒表面の温度が５００℃以上の高温になる。その結果、活性成分であるＶ２Ｏ５の蒸気圧が発生し（Ｖ２Ｏ５の融点は６９０℃）、排ガスに同伴されて触媒系外に飛散し、煙道に堆積するというトラブルが発生する。また、触媒からのＶ２Ｏ５の飛散は、触媒活性の低下および環境汚染という問題を発生させる。
【０００５】
【発明が解決しようとする課題】
本発明は上記実情に鑑みなされたものであり、その目的は、５００℃以上の高温の排ガスに曝されてもＶ２Ｏ５の飛散が抑制され性能が維持される耐熱性脱硝触媒を提供することにある。
【０００６】
【課題を解決するための手段】
本発明者は、上記課題を解決するため、種々検討を重ねた結果、バナジウム系脱硝触媒に特定元素の酸化物を含有させるならば、Ｖ２Ｏ５の飛散が起こる５００℃以上の高温の排ガス処理においてもＶ２Ｏ５の系外への飛散やそれに伴う脱硝性能低下が抑制されるとの知見を得た。
【０００７】
本発明は、上記の知見に基づき完成されたものであり、その要旨は、活性成分としてＶ２Ｏ５を含有し、担体成分として少なくともＴｉＯ２を含有する脱硝触媒に、添加成分として、３族元素、１３族元素、ランタノイド元素およびＭｇ、Ｎｂ、Ｃｒ，Ｆｅ，Ｃｏ，Ｎｉ、Ｃｕ、Ａｇ、Ｂ、Ｐｂ、Ｓｎの群から選択される少なくとも一種の元素の酸化物を含有せしめて成ることを特徴とする耐熱性脱硝触媒に存する。
【０００８】
【発明の実施の形態】
以下、本発明を詳細を説明する。
【０００９】
本発明の耐熱性脱硝触媒は、活性成分としてＶ２Ｏ５を含有し、担体成分として少なくともＴｉＯ２を含有する。担体成分の具体例としては、ＴｉＯ２、ＴｉＯ２−ＷＯ３、ＴｉＯ２−ＳｉＯ２、ＴｉＯ２−ＳｉＯ２−ＷＯ３、ＴｉＯ２−ＳｉＯ２−ＷＯ３等が挙げられる。
【００１０】
本発明の耐熱性脱硝触媒は、添加成分として、３族元素、１３族元素、ランタノイド元素およびＭｇ、Ｎｂ、Ｃｒ，Ｆｅ，Ｃｏ，Ｎｉ、Ｃｕ、Ａｇ、Ｂ、Ｐｂ、Ｓｎの群から選択される少なくとも一種の元素の酸化物を含有する。
【００１１】
３族元素としては、Ｓｃ、Ｙ、Ｌｕ、Ｌｒが挙げられ、好ましくはＹである。１３族元素としては、Ｂ、Ａｌ、Ｇａ、Ｉｎ、Ｔｅが挙げられ、好ましくはＢである。ランタノイド元素としては、Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕが挙げられる。
【００１２】
本発明の耐熱性脱硝触媒において、Ｖ２Ｏ５の含有量は、通常０．１〜３０ｗｔ％であり、添加成分の含有量は、通常０．１〜３０ｗｔ％、好ましくは０．１〜２０ｗｔ％である。添加成分の割合が余りに少ない場合はＶ２Ｏ５の飛散抑制効果が不十分となり、逆に、余りに多い場合は脱硝性能が低下することがある。なお、上記の含有量は、触媒全体の重量（活性成分、担体、添加成分の合計量）を基準とした値である。なお、上記の各成分の含有量の残余は担体の量である。
【００１３】
本発明の耐熱性脱硝触媒におけるＶ２Ｏ５の原料は、特に制限されないが、Ｖ２Ｏ５又はＮＨ４ＶＯ３（メタバナジン酸アンモニウム）が好適に使用される。これらの原料は、通常、シュウ酸水溶液またはモノメタノールアミン水溶液に溶解して原料液として使用される。
【００１４】
添加成分の金属酸化物の原料は、特に制限されないが、上記のＶ２Ｏ５原料と分子レベルで混合し得ることが好ましいとの観点から、水に溶解し易い原料が好適であり、具体的には硝酸塩や塩化物が好適に使用される。例えばイットリウム（Ｙ）の場合は硝酸イットリウム６水和物を水に溶解して原料液を調製するのが好ましい。
【００１５】
本発明の耐熱性脱硝触媒は、基本的には、前述の担体とＶ２Ｏ５の原料液と金属酸化物の原料液とを混合して成形した後に焼成する方法、または、成形した担体基材にＶ２Ｏ５の原料液と金属酸化物の原料液とを含浸させた後に焼成する方法により調製される。触媒の形状および大きさは、処理ガス量や、反応器の形状、大きさ等により適宜選択される。触媒の形状は、ハニカム状、円柱状、球状、板状などが挙げられる。
【００１６】
ハニカム形状の触媒を製造する方法として、（Ａ）担体成分とＶ２Ｏ５の原料液と金属酸化物の原料液とを成形助剤と共に混練した後に押出成形法などによりハニカム状の形状に賦形する方法、（Ｂ）ハニカム形状の基材上に担体成分とＶ２Ｏ５の原料液と金属酸化物の原料液を含浸・担持する方法を挙げることが出来る。添加成分として、イットリウムを含有するものを例として上述の製造方法（Ａ）を例示すれば、以下のようになる。
【００１７】
（１）メタバナジン酸アンモニウムを約１０ｗｔ％モノエタノールアミン水溶液に溶解する。
（２）硝酸イットリウム６水塩を純水に溶解する。
（３）硫酸チタン溶液を加熱溶解してメタチタン酸スラリーを得る。
（４）メタチタン酸スラリーに１５ｗｔ％アンモニア水を加えてｐＨ調整した後に加熱還流処理を１時間以上行う。
（５）上記の（４）のスラリーにパラタングステン酸アンモニウムを加え、更に、加熱還流処理を１時間以上行う。
（６）得られたスラリーを濾過し、得られたケーキを５０〜１５０℃の温度で３〜５０時間乾燥した後、４００℃〜６５０℃の温度で焼成し、冷却後に粉砕する。
（７）得られた粉末状のＷＯ３−ＴｉＯ２２元系複合酸化物担体と上記の（１）と（２）で調製した水溶液とをニーダーで混練する。
（８）上記の（７）で得られた混練物に、（ｉ）更に必要に応じ、成形助剤を加えて混練した混練物を押出成形し、５０〜１５０℃の温度で３〜５０時間乾燥した後、ＳＶ１００〜２０００Ｈｒ−１の空気気流中、４００〜６５０℃の温度で焼成する、または、（ｉ ｉ）混練物を５０〜１５０℃の温度で３〜５０時間乾燥し、４００〜６５０℃の温度で焼成した後、成形助剤を加えて成形する。
【００１８】
また、上述の製造方法（Ｂ）の一例として次の方法が例示される。すなわち、円柱状、球状、ハニカム状、板状など所望の形状の基材上に上記の（３）〜（５）で調製した担体成分をコーティングし、上記の（１）と（２）で調製した水溶液を塗布して活性成分を含浸させ、５０〜１５０℃で３〜５０時間乾燥した後、４００〜６５０℃の温度で焼成する。
【００１９】
混練・成形方法のように添加した原料すべてが活性成分となる場合は、それぞれの金属塩などの原料成分が対応する金属酸化物に変化したものとして触媒組成は添加量から推算する。また、含浸法で製造された場合は触媒をフッ化水素酸で処理した後、硫酸アンモニウムで融解してプラズマ発光分析法（ＩＣＰ−ＡＥＳ分析法）によって触媒組成を測定する。
【００２０】
本発明の耐熱性脱硝触媒は、排ガス中の窒素酸化物（ＮＯｘ）を還元して除去する方法として、各種の排ガスの脱硝方法に適用される。還元剤としては、アンモニア及び／又は尿素液が好適である。
【００２１】
特に、本発明の耐熱性脱硝触媒は、その優れた耐熱性を活かし、ＮＯｘと共に、炭素を１原子換算で０．２モル／ｈｒ・ｇ−ｃａｔ以上含有する排ガスの脱硝に好適に使用される。そして本発明の耐熱性脱硝触媒、触媒表面温度が一時的に５００℃以上の高温になっても活性成分であるＶ２Ｏ５の飛散は抑制される。排ガスは、水分と共に酸素を含有するが、その含有量は、通常０．５〜２５ｖｏｌ％、好ましくは１〜２１ｖｏｌ％である。なお、ボイラー排ガスの場合、必要に応じ、その前段にアルカリ洗浄塔などの塩酸除去設備やＳＯｘ除去設備、電気集塵機やバグフィルター等のダスト除去装置などの前処理工程があってもよい。
【００２２】
触媒層の圧力は、ゲージ圧として、通常−０．０５〜０．９ＭＰａ、好ましくは−０．０１〜０．５ＭＰａである。また、空間速度（ＳＶ）は、通常１００〜１０００００Ｈｒ−１、好ましくは１０００〜５００００Ｈｒ−１である。
【００２３】
【実施例】
以下、本発明を実施例により詳細に説明するが、本発明はその要旨を超えない限り以下の実施例により限定されるものではない。以下の諸例で得られた触媒のＶ２Ｏ５飛散テスト、Ｖ２Ｏ５の定量および脱硝性能評価は次の方法で行った。
【００２４】
（１）Ｖ２Ｏ５飛散テスト：
石英ガラス製の反応管（内径３０ｍｍ長さ６００ｍｍ）中央部に試作した３ｍｍφ長さ５〜１５ｍｍの円柱状触媒２０ｍｌをセットし、内径４０ｍｍ、外径２００ｍｍ、長さ４５０ｍｍの管状加熱炉にセットした。ローターメータにより、１８０Ｌ／Ｈｒ（ＮＴＰ）のＮ２と２０Ｌ／Ｈｒ（ＮＴＰ）のＯ２を触媒上に導入し、６５０℃で２０時間加熱処理した。
【００２５】
管状炉の外部に位置し、自然冷却される石英反応管最下部に飛散したＶ２Ｏ５をトラップするためのトラップ材（ＳｉＯ２ビーズ：富士シリシア社製「ＣＡＲＩＡＣＴ Ｑ−５０」７５〜５００μｍ）を５ｃｃ充填して処理を実施し、処理後付着したＶ２Ｏ５量を定量した。触媒層下流直後からトラップ材までのガラス管壁に付着したものは３０ｇ／Ｌシュウ酸水溶液に一晩浸漬し、シュウ酸水溶液中に溶解したＶ２Ｏ５量を定量し、トラップ材のＶ２Ｏ５量との合計量を飛散量とした。
【００２６】
（２）Ｖ２Ｏ５定量方法：
先ず、次の前処理を行った。すなわち、上記のシュウ酸水溶液は、濃縮後有機物を除去する目的で酸分解を実施し、更にＳｉを除去するためにＨＦ処理し、評価サンプルを得た。トラップ材はそのままＨＦ処理した後に酸分解し、評価サンプルを得た。次いで、評価サンプルについて、ＩＣＰ−ＡＥＳ装置（堀場製作所製「ＪＹ−１３８Ｕ」）を使用し、検量線法で測定した。
【００２７】
（３）脱硝性能評価方法：
石英ガラス製の反応管（内径３０ｍｍ長さ６００ｍｍ）の中央部に試作した３ｍｍφ長さ５ｍｍ〜１５ｍｍの評価する円柱状触媒２０ｍｌをセットし、内径４０ｍｍ、外径２００ｍｍ、長さ４５０ｍｍの管状加熱炉にセットした。Ｏ２：１０％、Ｈ２Ｏ：６％、ＮＨ３／ＮＯ＝１２０ｐｐｍ／１００ｐｐｍ、Ｎ２：バランス量の組成のガスを２００Ｌ／Ｈｒ（ＮＴＰ）の流量で触媒上に導入し、２００℃、２５０℃、３００℃、３５０℃、４００℃における脱硝性能を測定した。ＮＯｘ計はヤナコ製「ＥＣＬ−８８Ａ」を使用した。脱硝性能評価は、６５０℃・２０時間加熱処理した触媒（Ｖ２Ｏ５飛散テスト品）と未処理の触媒（Ｆｒｅｓｈ品）とについて行った。
【００２８】
実施例１
メタバナジン酸アンモニウム３４７ｇとパラタングステン酸アンモニウム９４３ｇを８０℃に加温した１０ｗｔ％モノエタノールアミン水溶液６０００ｇに溶解して原料液（１）を調製した。さらに硝酸イットリウム（ＩＩＩ）６水和物３０５ｇを８０℃に加温した純水１０００ｇに溶解して原料液（２）を調製した。ＴｉＯ２粉末（石原産業製「ＭＣ−９０」）７８３０ｇ、成形助剤として、カオリン（ミノセラミックス社製）１０００ｇ、ポリエチレンオキサイド（明和化学工業社製「アルコックス Ｅ−３０」）５００ｇおよび結晶性セルロース（旭化成社製「アビセルＴＧ−１０１」）２００ｇを双腕型ニーダーで２時間混合した後、原料液（１）と原料液（２）を上記の双腕型ニーダーに添加し、３時間混練した。得られた混練物を押出機より３ｍｍ直径の円柱状に成形した。得られた成型物を１３０℃の温度で２４時間乾燥し、次いで空気流通下、ＳＶ１００ｈ−１、温度４２０℃の条件下で３時間焼成し、表１に示す触媒（Ａ）を得た。得られた触媒についてのＶ２Ｏ５飛散テスト及び脱硝性能評価の結果を表２及び表３に示す。
【００２９】
実施例２
実施例１において、硝酸イットリウム（ＩＩＩ）６水和物の量を９１．６ｇにし、ＴｉＯ２粉末を７８９３ｇにした以外は、実施例１と同様に操作し、表１に示す触媒Ｂを調製して評価した。
【００３０】
実施例３
実施例１において、硝酸ランタン（ＩＩＩ）６水和物２３９ｇを８０℃に加温した純水１０００ｇに溶解し原料液（２）にした以外は、実施例１と同様に操作し、表１に示す触媒Ｃを調製して評価した。
【００３１】
実施例４
実施例１において、硝酸セリウム（ＩＩＩ）６水和物２２７ｇを８０℃に加温した純水１０００ｇに溶解し原料液（２）にした以外は、実施例１と同様に操作し、表１に示す触媒Ｄを調製して評価した。
【００３２】
実施例５
実施例１において、硝酸サマリウム（ＩＩＩ）６水和物２２９ｇを８０℃に加温した純水１０００ｇに溶解し原料液（２）にした以外は、実施例１と同様に操作し、表１に示す触媒Ｅを調製して評価した。
【００３３】
実施例６
実施例１において、硝酸エルビウム（ＩＩＩ）５水和物２０８ｇを８０℃に加温した純水１０００ｇに溶解し原料液（２）にした以外は、実施例１と同様に操作し、表１に示す触媒Ｆを調製して評価した。
【００３４】
実施例７
実施例１において、硝酸プラセオジム（ＩＩＩ）６水和物２３７ｇを８０℃に加温した純水１０００ｇに溶解し原料液（２）にした以外は、実施例１と同様に操作し、表１に示す触媒Ｇを調製して評価した。
【００３５】
実施例８
実施例１において、硝酸イッテルビウム（ＩＩＩ）４水和物１９７ｇを８０℃に加温した純水１０００ｇに溶解し原料液（２）にした以外は、実施例１と同様に操作し、表１に示す触媒Ｈを調製して評価した。
【００３６】
実施例９
実施例１において、硝酸タリウム（ＩＩＩ）３水和物１７５ｇを８０℃に加温した純水１０００ｇに溶解し原料液（２）にした以外は、実施例１と同様に操作し、表１に示す触媒Ｉを調製して評価した。
【００３７】
実施例１０
実施例１において、硝酸マグネシウム（ＩＩ）６水和物９１５ｇを８０℃に加温した純水２５００ｇに溶解し原料液（２）にし、ＴｉＯ２粉末量を７７７６ｇにした以外は、実施例１と同様に操作し、表１に示す触媒Ｊを調製して評価した。
【００３８】
実施例１１
実施例１において、硝酸クロム（ＩＩＩ）９水和物４７４ｇを８０℃に加温した純水１０００ｇに溶解し原料液（２）にした以外は、実施例１と同様に操作し、表１に示す触媒Ｋを調製して評価した。
【００３９】
実施例１２
実施例１において、硝酸第２鉄（ＩＩＩ）９水和物４５５ｇを８０℃に加温した純水１０００ｇに溶解し原料液（２）にした以外は、実施例１と同様に操作し、表１に示す触媒Ｌを調製して評価した。
【００４０】
実施例１３
実施例１において、硝酸ニッケル（ＩＩ）６水和物３５０ｇを８０℃に加温した純水１０００ｇに溶解し原料液（２）にした以外は、実施例１と同様に操作し、表１に示す触媒Ｍを調製して評価した。
【００４１】
実施例１４
実施例１において、硝酸コバルト（ＩＩ）６水和物３５０ｇを８０℃に加温した純水１０００ｇに溶解し原料液（２）にした以外は、実施例１と同様に操作し、表１に示す触媒Ｎを調製して評価した。
【００４２】
実施例１５
実施例１において、硝酸銅（ＩＩ）３水和物２７３ｇを８０℃に加温した純水１０００ｇに溶解し原料液（２）にした以外は、実施例１と同様に操作し、表１に示す触媒Ｏを調製して評価した。
【００４３】
実施例１６
実施例１において、硝酸銀（Ｉ）１２３ｇを８０℃に加温した純水１０００ｇに溶解し原料液（２）にした以外は、実施例１と同様に操作し、表１に示す触媒Ｐを調製して評価した。
【００４４】
実施例１７
実施例１において、ホウ酸１６０ｇを８０℃に加温した純水１０００ｇに溶解し原料液（２）にした以外は、実施例１と同様に操作し、表１に示す触媒Ｑを調製して評価した。
【００４５】
実施例１８
実施例１において、硝酸鉛（ＩＩ）１３４ｇを８０℃に加温した純水１０００ｇに溶解し原料液（２）にした以外は、実施例１と同様に操作し、表１に示す触媒Ｒを調製して評価した。
【００４６】
実施例１９
実施例１において、塩化スズ（ＩＩ）２水和物１３５ｇを８０℃に加温し、６Ｎ塩酸を１ｍｌ加えた純水１０００ｇに溶解し原料液（２）にした以外は、実施例１と同様に操作し、表１に示す触媒Ｓを調製して評価した。
【００４７】
実施例２０
実施例１において、シュウ酸ニオブアンモニウム（Ｎｂ２Ｏ５として２５ｗｔ％品）３６０ｇを８０℃に加温した純水３０００ｇに溶解し原料液（２）にして、ＴｉＯ２粉末量を７０２０ｇにした以外は、実施例１と同様に操作し、表１に示す触媒Ｔを調製して評価した。
【００４８】
比較例１
実施例１において、添加成分の原料液（２）を添加しない以外は、実施例１と同様に操作し、表１に示す触媒Ｕを調製して評価した。
【００４９】
【表１】
【表２】
【表３】
【発明の効果】
以上説明した本発明によれば、排ガス中の未燃有機化合物の分解反応による発熱によるＶ２Ｏ５の飛散も抑制された耐熱性脱硝触媒が提供され、本発明の工業的価値は顕著である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat-resistant denitration catalyst, and in particular, relates to a vanadium-based denitration catalyst, which is capable of scattering V 2 O 5 into a gas when high-temperature exhaust gas having a temperature of 500 ° C. or more passes through, and has a problem of environmental degradation. The present invention relates to a heat-resistant denitration catalyst with reduced pollution.
[0002]
[Prior art]
A method for removing nitrogen oxides from exhaust gas using a vanadium-based denitration catalyst (for example, see Patent Document 1) has been put to practical use in various fields.
[0003]
[Patent Document 1]
JP-A-50-51966
In recent years, the quality of fuel used in boilers, such as thermal power generation, has declined due to cost savings. Therefore, the amount of unburned organic matter is increasing. Usually, when an organic substance passes through a vanadium-based denitration catalyst layer, a combustion reaction occurs at a temperature of about 350 ° C., and the organic substance is rendered harmless. However, the use of low-grade fuel increases the amount of organic matter remaining in the boiler, resulting in an enormous amount of heat generated by the combustion reaction in the denitration catalyst layer, and the temperature of the catalyst surface becomes as high as 500 ° C. or higher. As a result, a vapor pressure of V 2 O 5 as an active component is generated (melting point of V 2 O 5 is 690 ° C.), and it is accompanied by the exhaust gas and scatters out of the catalyst system to cause a trouble of being deposited on a flue. I do. Further, the scattering of V 2 O 5 from the catalyst causes problems such as a decrease in catalytic activity and environmental pollution.
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a heat-resistant denitration catalyst in which scattering of V 2 O 5 is suppressed and performance is maintained even when exposed to high-temperature exhaust gas of 500 ° C. or more. It is in.
[0006]
[Means for Solving the Problems]
The present inventor has conducted various studies in order to solve the above-mentioned problems. As a result, if a vanadium-based denitration catalyst contains an oxide of a specific element, high-temperature exhaust gas of 500 ° C. or more at which scattering of V 2 O 5 occurs. It has been found that also in the treatment, scattering of V 2 O 5 to the outside of the system and the accompanying decrease in denitration performance are suppressed.
[0007]
The present invention has been completed based on the above-mentioned findings, and the gist of the present invention is to provide a denitration catalyst containing V 2 O 5 as an active ingredient and at least TiO 2 as a carrier ingredient, and a Group III catalyst as an additional ingredient. Element, a group 13 element, a lanthanoid element and an oxide of at least one element selected from the group consisting of Mg, Nb, Cr, Fe, Co, Ni, Cu, Ag, B, Pb, and Sn. Exists in the characteristic heat-resistant denitration catalyst.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
[0009]
The heat-resistant denitration catalyst of the present invention contains V 2 O 5 as an active component and at least TiO 2 as a carrier component. Specific examples of the carrier component include TiO 2 , TiO 2 —WO 3 , TiO 2 —SiO 2 , TiO 2 —SiO 2 —WO 3 , TiO 2 —SiO 2 —WO 3, and the like.
[0010]
The heat-resistant denitration catalyst of the present invention is selected from the group consisting of Group III elements, Group XIII elements, lanthanoid elements and Mg, Nb, Cr, Fe, Co, Ni, Cu, Ag, B, Pb and Sn as additional components. At least one element oxide.
[0011]
Examples of Group 3 elements include Sc, Y, Lu, and Lr, and Y is preferable. Group 13 elements include B, Al, Ga, In, and Te, with B being preferred. Examples of the lanthanoid element include La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.
[0012]
In the heat resistance denitration catalyst of the present invention, the content of V 2 O 5 is usually 0.1-30%, the content of the additive component is generally 0.1-30%, preferably 0.1~20wt %. If the proportion of the added component is too small, the effect of suppressing the scattering of V 2 O 5 becomes insufficient, and if it is too large, the denitration performance may be reduced. The above content is a value based on the weight of the entire catalyst (the total amount of the active component, the carrier, and the additional component). The balance of the contents of the above components is the amount of the carrier.
[0013]
Although the raw material of V 2 O 5 in the heat-resistant denitration catalyst of the present invention is not particularly limited, V 2 O 5 or NH 4 VO 3 (ammonium metavanadate) is preferably used. These raw materials are usually used as a raw material liquid by dissolving in an oxalic acid aqueous solution or an aqueous solution of monomethanolamine.
[0014]
The raw material of the metal oxide as an additional component is not particularly limited, but from the viewpoint that it is preferable to be able to be mixed with the above-mentioned V 2 O 5 raw material at the molecular level, a raw material that is easily dissolved in water is preferable. Nitrate and chloride are preferably used for the slag. For example, in the case of yttrium (Y), it is preferable to dissolve yttrium nitrate hexahydrate in water to prepare a raw material liquid.
[0015]
The heat-resistant denitration catalyst of the present invention is basically prepared by mixing the above-mentioned carrier, the raw material liquid of V 2 O 5 and the raw material liquid of the metal oxide, molding the mixture, and then calcining the mixture. It is prepared by a method in which a material is impregnated with a raw material liquid of V 2 O 5 and a raw material liquid of a metal oxide and then fired. The shape and size of the catalyst are appropriately selected depending on the processing gas amount, the shape and size of the reactor, and the like. Examples of the shape of the catalyst include a honeycomb shape, a column shape, a spherical shape, and a plate shape.
[0016]
As a method for producing a honeycomb-shaped catalyst, (A) a carrier component, a raw material liquid of V 2 O 5, and a raw material liquid of a metal oxide are kneaded together with a forming aid, and then the mixture is applied to a honeycomb shape by an extrusion molding method or the like. And (B) a method in which a carrier component, a raw material liquid of V 2 O 5, and a raw material liquid of a metal oxide are impregnated and supported on a honeycomb-shaped base material. The following is an example of the above-mentioned production method (A), taking as an example an additive containing yttrium.
[0017]
(1) Ammonium metavanadate is dissolved in an aqueous solution of about 10 wt% monoethanolamine.
(2) Dissolve yttrium nitrate hexahydrate in pure water.
(3) The titanium sulfate solution is heated and dissolved to obtain a metatitanic acid slurry.
(4) After adjusting the pH by adding 15 wt% aqueous ammonia to the metatitanic acid slurry, a heating and reflux treatment is performed for 1 hour or more.
(5) Ammonium paratungstate is added to the slurry of (4), and a heating and refluxing treatment is performed for 1 hour or more.
(6) The obtained slurry is filtered, and the obtained cake is dried at a temperature of 50 to 150 ° C. for 3 to 50 hours, calcined at a temperature of 400 ° C. to 650 ° C., and crushed after cooling.
(7) The resulting powdery WO 3 -TiO 2 2-element composite oxide support and the (1) and an aqueous solution prepared in (2) kneading in a kneader.
(8) To the kneaded product obtained in (7) above, (i) a kneaded product obtained by further kneading by adding a molding aid, if necessary, is extruded, and is subjected to extrusion at a temperature of 50 to 150 ° C for 3 to 50 hours. After drying, baking is performed at a temperature of 400 to 650 ° C. in an air stream of SV 100 to 2000 Hr −1 , or (ii) the kneaded material is dried at a temperature of 50 to 150 ° C. for 3 to 50 hours, and then dried. After baking at a temperature of ° C., a molding aid is added to mold.
[0018]
The following method is exemplified as an example of the above-described manufacturing method (B). That is, the carrier component prepared in the above (3) to (5) is coated on a substrate having a desired shape such as a columnar shape, a spherical shape, a honeycomb shape, and a plate shape, and prepared in the above (1) and (2). The resulting aqueous solution is applied to impregnate the active ingredient, dried at 50 to 150 ° C. for 3 to 50 hours, and fired at a temperature of 400 to 650 ° C.
[0019]
In the case where all the added raw materials become active components as in the kneading / forming method, the catalyst composition is estimated from the added amount on the assumption that the raw material components such as metal salts have changed into the corresponding metal oxides. When the catalyst is manufactured by the impregnation method, the catalyst is treated with hydrofluoric acid, melted with ammonium sulfate, and the catalyst composition is measured by a plasma emission analysis method (ICP-AES analysis method).
[0020]
The heat-resistant denitration catalyst of the present invention is applied to various types of exhaust gas denitration methods as a method for reducing and removing nitrogen oxides (NOx) in the exhaust gas. As the reducing agent, ammonia and / or urea liquid is suitable.
[0021]
In particular, the heat-resistant denitration catalyst of the present invention makes use of its excellent heat resistance and is suitably used for denitration of exhaust gas containing 0.2 mol / hr.g-cat or more of carbon per atom together with NOx. . And, even if the surface temperature of the heat-resistant denitration catalyst of the present invention temporarily rises to 500 ° C. or more, scattering of the active component V 2 O 5 is suppressed. The exhaust gas contains oxygen together with water, and the content is usually 0.5 to 25 vol%, preferably 1 to 21 vol%. In the case of boiler exhaust gas, if necessary, a pretreatment step such as a hydrochloric acid removing facility such as an alkali washing tower, a SOx removing facility, and a dust removing device such as an electric dust collector or a bag filter may be provided in the preceding stage.
[0022]
The pressure of the catalyst layer is usually -0.05 to 0.9 MPa, preferably -0.01 to 0.5 MPa as a gauge pressure. Also, the space velocity (SV) is usually 100～100000Hr -1, preferably 1000~50000Hr -1.
[0023]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the present invention. The V 2 O 5 scattering test, V 2 O 5 quantification, and denitration performance evaluation of the catalysts obtained in the following examples were performed by the following methods.
[0024]
(1) V 2 O 5 scattering test:
At the center of a quartz glass reaction tube (inner diameter 30 mm, length 600 mm), 20 ml of a prototype 3 mmφ, 5 to 15 mm long cylindrical catalyst was set, and set in a tubular heating furnace having an inner diameter of 40 mm, an outer diameter of 200 mm, and a length of 450 mm. . 180 L / Hr (NTP) of N 2 and 20 L / Hr (NTP) of O 2 were introduced on the catalyst by a rotor meter, and heat treatment was performed at 650 ° C. for 20 hours.
[0025]
Located outside of the tubular furnace, naturally cooled is quartz reaction tube bottom trap for trapping V 2 O 5 scattered into material (SiO 2 beads: Fuji Silysia Chemical Ltd., "CARIACT Q-50" 75～500Myuemu) Was filled in 5 cc to carry out the treatment, and the amount of V 2 O 5 adhered after the treatment was quantified. What adhered to the glass tube wall from immediately downstream of the catalyst layer to the trap material was immersed in a 30 g / L oxalic acid aqueous solution overnight, the amount of V 2 O 5 dissolved in the oxalic acid aqueous solution was quantified, and the V 2 of the trap material was determined. the total amount of O 5 content was scattered amount.
[0026]
(2) V 2 O 5 determination method:
First, the following pretreatment was performed. That is, the oxalic acid aqueous solution was subjected to acid decomposition for the purpose of removing organic matter after concentration, and then subjected to HF treatment for removing Si, thereby obtaining an evaluation sample. The trap material was subjected to HF treatment as it was and then subjected to acid decomposition to obtain an evaluation sample. Next, the evaluation sample was measured by a calibration curve method using an ICP-AES device (“JY-138U” manufactured by Horiba, Ltd.).
[0027]
(3) Denitration performance evaluation method:
At the center of a quartz glass reaction tube (inner diameter 30 mm, length 600 mm), 20 ml of a prototype 3 mmφ 5 mm to 15 mm cylindrical catalyst to be evaluated was set, and a tubular heating furnace having an inner diameter of 40 mm, an outer diameter of 200 mm, and a length of 450 mm. Set to. O 2 : 10%, H 2 O: 6%, NH 3 / NO = 120 ppm / 100 ppm, N 2 : A gas having a composition of a balance amount is introduced onto the catalyst at a flow rate of 200 L / Hr (NTP), and the temperature is 200 ° C. The denitration performance at 250 ° C, 300 ° C, 350 ° C, and 400 ° C was measured. The NOx meter used was "ECL-88A" manufactured by Yanaco. The denitration performance evaluation was performed on a catalyst (V 2 O 5 scattering test product) heat-treated at 650 ° C. for 20 hours and an untreated catalyst (Fresh product).
[0028]
Example 1
A raw material liquid (1) was prepared by dissolving 347 g of ammonium metavanadate and 943 g of ammonium paratungstate in 6000 g of a 10 wt% aqueous monoethanolamine solution heated to 80 ° C. Further, 305 g of yttrium (III) nitrate hexahydrate was dissolved in 1000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2). 7,830 g of TiO 2 powder (“MC-90” manufactured by Ishihara Sangyo), 1000 g of kaolin (manufactured by Mino Ceramics), 500 g of polyethylene oxide (“Alcox E-30” manufactured by Meiwa Chemical Industry Co., Ltd.) and 500 g of crystalline cellulose as molding aids After mixing 200 g of "Abicel TG-101" (manufactured by Asahi Kasei Corporation) with a double-arm kneader for 2 hours, the raw material liquid (1) and the raw material liquid (2) were added to the above-mentioned double-arm kneader and kneaded for 3 hours. . The obtained kneaded material was formed into a cylindrical shape having a diameter of 3 mm from an extruder. The obtained molded product was dried at a temperature of 130 ° C. for 24 hours, and then calcined for 3 hours under a condition of SV 100 h −1 and a temperature of 420 ° C. in an air flow to obtain a catalyst (A) shown in Table 1. Tables 2 and 3 show the results of the V 2 O 5 scattering test and the evaluation of the denitration performance of the obtained catalyst.
[0029]
Example 2
Catalyst B shown in Table 1 was prepared in the same manner as in Example 1 except that the amount of yttrium (III) nitrate hexahydrate was changed to 91.6 g and the amount of TiO 2 powder was changed to 7893 g. Was evaluated.
[0030]
Example 3
The procedure of Example 1 was repeated, except that 239 g of lanthanum (III) nitrate hexahydrate was dissolved in 1000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2). The catalyst C shown was prepared and evaluated.
[0031]
Example 4
The procedure of Example 1 was repeated, except that 227 g of cerium (III) nitrate hexahydrate was dissolved in 1000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2). The catalyst D shown was prepared and evaluated.
[0032]
Example 5
The procedure of Example 1 was repeated, except that 229 g of samarium (III) nitrate hexahydrate was dissolved in 1000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2). The catalyst E shown was prepared and evaluated.
[0033]
Example 6
The procedure of Example 1 was repeated, except that 208 g of erbium (III) nitrate pentahydrate was dissolved in 1000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2). The catalyst F shown was prepared and evaluated.
[0034]
Example 7
The procedure of Example 1 was repeated, except that 237 g of praseodymium (III) nitrate hexahydrate was dissolved in 1000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2). The catalyst G shown was prepared and evaluated.
[0035]
Example 8
The procedure of Example 1 was repeated except that 197 g of ytterbium (III) nitrate tetrahydrate was dissolved in 1000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2). The catalyst H shown was prepared and evaluated.
[0036]
Example 9
The procedure of Example 1 was repeated, except that 175 g of thallium (III) nitrate trihydrate was dissolved in 1000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2). The catalyst I shown was prepared and evaluated.
[0037]
Example 10
Example 1 was repeated except that 915 g of magnesium (II) nitrate hexahydrate was dissolved in 2500 g of pure water heated to 80 ° C. to prepare a raw material liquid (2), and the amount of TiO 2 powder was changed to 7776 g. The same operation was performed to prepare and evaluate the catalyst J shown in Table 1.
[0038]
Example 11
The procedure of Example 1 was repeated, except that 474 g of chromium (III) nitrate nonahydrate was dissolved in 1000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2). The catalyst K shown was prepared and evaluated.
[0039]
Example 12
The procedure of Example 1 was repeated, except that 455 g of ferric (III) nitrate nonahydrate was dissolved in 1000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2). Catalyst L shown in No. 1 was prepared and evaluated.
[0040]
Example 13
The procedure of Example 1 was repeated, except that 350 g of nickel (II) nitrate hexahydrate was dissolved in 1000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2). The indicated catalyst M was prepared and evaluated.
[0041]
Example 14
The procedure of Example 1 was repeated, except that 350 g of cobalt (II) nitrate hexahydrate was dissolved in 1000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2). The catalyst N shown was prepared and evaluated.
[0042]
Example 15
The procedure of Example 1 was repeated, except that 273 g of copper (II) nitrate trihydrate was dissolved in 1000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2). The catalyst O shown was prepared and evaluated.
[0043]
Example 16
Catalyst P shown in Table 1 was prepared in the same manner as in Example 1 except that 123 g of silver (I) nitrate was dissolved in 1000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2). Was evaluated.
[0044]
Example 17
Catalyst Q shown in Table 1 was prepared in the same manner as in Example 1, except that 160 g of boric acid was dissolved in 1000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2). evaluated.
[0045]
Example 18
Catalyst R shown in Table 1 was prepared in the same manner as in Example 1 except that 134 g of lead (II) nitrate was dissolved in 1000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2). Prepared and evaluated.
[0046]
Example 19
In the same manner as in Example 1, except that 135 g of tin (II) chloride dihydrate was heated to 80 ° C. and dissolved in 1000 g of pure water to which 1 mL of 6N hydrochloric acid was added to prepare a raw material liquid (2). The catalyst S shown in Table 1 was prepared and evaluated.
[0047]
Example 20
In Example 1, except that 360 g of ammonium niobium oxalate (25 wt% as Nb 2 O 5 ) was dissolved in 3000 g of pure water heated to 80 ° C. to prepare a raw material liquid (2), and the amount of TiO 2 powder was changed to 7020 g. Was operated in the same manner as in Example 1 to prepare and evaluate the catalyst T shown in Table 1.
[0048]
Comparative Example 1
The procedure of Example 1 was repeated, except that the raw material liquid (2) of the additional component was not added, to prepare and evaluate the catalyst U shown in Table 1.
[0049]
[Table 1]
[Table 2]
[Table 3]
【The invention's effect】
According to the present invention described above, there is provided a heat-resistant denitration catalyst in which scattering of V 2 O 5 due to heat generated by a decomposition reaction of unburned organic compounds in exhaust gas is suppressed, and the industrial value of the present invention is remarkable. .
Claims (3)
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| KR101083307B1 (en) | 2009-08-18 | 2011-11-15 | 한국전력공사 | V2o6 based catalyst |
| JP2014522305A (en) * | 2011-05-30 | 2014-09-04 | バブコック・アンド・ウィルコックス・パワー・ジェネレイション・グループ・インコーポレイテッド | Catalyst with improved poison resistance |
| JP2021502893A (en) * | 2017-11-14 | 2021-02-04 | ユミコア・アクチエンゲゼルシャフト・ウント・コムパニー・コマンディットゲゼルシャフトＵｍｉｃｏｒｅ ＡＧ ＆ Ｃｏ．ＫＧ | SCR catalyst |
| WO2019096786A1 (en) * | 2017-11-14 | 2019-05-23 | Umicore Ag & Co. Kg | Scr catalyst |
| CN111356525A (en) * | 2017-11-14 | 2020-06-30 | 优美科股份公司及两合公司 | SCR catalyst |
| EP3482824A1 (en) * | 2017-11-14 | 2019-05-15 | Umicore Ag & Co. Kg | Scr catalytic converter |
| US11135571B2 (en) | 2017-11-14 | 2021-10-05 | Umicore Ag & Co. Kg | SCR catalyst |
| US11492945B2 (en) | 2017-11-14 | 2022-11-08 | Umicore Ag & Co. Kg | SCR catalyst |
| US11498055B2 (en) | 2017-11-14 | 2022-11-15 | Umicore Ag & Co. Kg | SCR catalyst |
| JP7323520B2 (en) | 2017-11-14 | 2023-08-08 | ユミコア・アクチエンゲゼルシャフト・ウント・コムパニー・コマンディットゲゼルシャフト | SCR catalyst |
| CN111356525B (en) * | 2017-11-14 | 2023-09-15 | 优美科股份公司及两合公司 | SCR catalyst |
| CN111939950A (en) * | 2019-05-16 | 2020-11-17 | 新淳(上海)环保科技有限公司 | Denitration catalyst for circulating fluidized bed boiler and preparation method thereof |
| CN115814783A (en) * | 2022-12-29 | 2023-03-21 | 华电电力科学研究院有限公司 | Anti-potassium poisoning SCR denitration catalyst and preparation method thereof |
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