JP4730998B2 - Exhaust gas purification catalyst and exhaust gas purification device - Google Patents
Exhaust gas purification catalyst and exhaust gas purification device Download PDFInfo
- Publication number
- JP4730998B2 JP4730998B2 JP2000228440A JP2000228440A JP4730998B2 JP 4730998 B2 JP4730998 B2 JP 4730998B2 JP 2000228440 A JP2000228440 A JP 2000228440A JP 2000228440 A JP2000228440 A JP 2000228440A JP 4730998 B2 JP4730998 B2 JP 4730998B2
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- catalyst
- gas purification
- gas purifying
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 239000003054 catalyst Substances 0.000 title claims description 65
- 238000000746 purification Methods 0.000 title claims description 7
- 239000000463 material Substances 0.000 claims description 19
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 13
- 230000003197 catalytic effect Effects 0.000 claims description 10
- 238000006243 chemical reaction Methods 0.000 claims description 9
- 230000000737 periodic effect Effects 0.000 claims description 9
- 229910052748 manganese Inorganic materials 0.000 claims description 7
- 229910052751 metal Inorganic materials 0.000 claims description 7
- 239000002184 metal Substances 0.000 claims description 7
- 229910052749 magnesium Inorganic materials 0.000 claims description 6
- 229910052758 niobium Inorganic materials 0.000 claims description 5
- 229910052715 tantalum Inorganic materials 0.000 claims description 5
- 239000007789 gas Substances 0.000 description 46
- 239000000126 substance Substances 0.000 description 17
- 150000002013 dioxins Chemical class 0.000 description 11
- 238000001816 cooling Methods 0.000 description 9
- 239000002243 precursor Substances 0.000 description 9
- HGUFODBRKLSHSI-UHFFFAOYSA-N 2,3,7,8-tetrachloro-dibenzo-p-dioxin Chemical compound O1C2=CC(Cl)=C(Cl)C=C2OC2=C1C=C(Cl)C(Cl)=C2 HGUFODBRKLSHSI-UHFFFAOYSA-N 0.000 description 7
- 239000002131 composite material Substances 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 239000000428 dust Substances 0.000 description 6
- 239000011572 manganese Substances 0.000 description 6
- 238000002844 melting Methods 0.000 description 6
- 230000008018 melting Effects 0.000 description 6
- 239000008188 pellet Substances 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 239000013078 crystal Substances 0.000 description 5
- 238000000354 decomposition reaction Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000011777 magnesium Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 239000010955 niobium Substances 0.000 description 4
- 239000000567 combustion gas Substances 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- -1 dioxin organochlorine compounds Chemical class 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 229910044991 metal oxide Inorganic materials 0.000 description 3
- 150000004706 metal oxides Chemical class 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 239000013543 active substance Substances 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 150000004045 organic chlorine compounds Chemical class 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 231100000331 toxic Toxicity 0.000 description 2
- 230000002588 toxic effect Effects 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 229910052692 Dysprosium Inorganic materials 0.000 description 1
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910021380 Manganese Chloride Inorganic materials 0.000 description 1
- GLFNIEUTAYBVOC-UHFFFAOYSA-L Manganese chloride Chemical compound Cl[Mn]Cl GLFNIEUTAYBVOC-UHFFFAOYSA-L 0.000 description 1
- 229910017493 Nd 2 O 3 Inorganic materials 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 229910052772 Samarium Inorganic materials 0.000 description 1
- 238000003723 Smelting Methods 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 1
- UNTBPXHCXVWYOI-UHFFFAOYSA-O azanium;oxido(dioxo)vanadium Chemical compound [NH4+].[O-][V](=O)=O UNTBPXHCXVWYOI-UHFFFAOYSA-O 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 238000003421 catalytic decomposition reaction Methods 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000010791 domestic waste Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000003987 high-resolution gas chromatography Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- 229910001338 liquidmetal Inorganic materials 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 239000011565 manganese chloride Substances 0.000 description 1
- 229940099607 manganese chloride Drugs 0.000 description 1
- 235000002867 manganese chloride Nutrition 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 238000002459 porosimetry Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- 238000009283 thermal hydrolysis Methods 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- 239000003440 toxic substance Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Description
【０００１】
【発明の属する技術分野】
本発明は、排ガス浄化用触媒と排ガス浄化装置、特に、焼却炉から発生するダイオキシン類有機塩素化合物及びその前駆体、例えば芳香族炭化水素化合物等の有害物質を分解除去するための排ガス浄化用触媒とそれを用いた排ガス浄化装置に関する。
【０００２】
【従来技術】
有機塩素化合物は、人体にとって有害な物質として知られており、特に近年では廃棄物の焼却により毒性が強いダイオキシン類有害物質の発生が指摘されており、環境問題として深刻な社会問題となっている。そのため、ダイオキシン類有害物質の除去に種々の方法が提案されている。
【０００３】
ダイオキシン類有害物質の除去方法としては、吸着剤への吸着除去、高温での燃焼分解等の方法が挙げられるが、近年、ダイオキシン類有害物質を触媒による分解除去が提案されている。この方法では、例えば、特許第２６３３３１６号公報では、燃焼排ガスをガス冷却塔で冷却された後、電気集塵器で除塵され、１５０〜２９０℃の温度で、酸化チタン担体にＶ2Ｏ5とＷＯ3を担持させた触媒と接触させて前記排ガス中の有機塩素化合物を分解するものである。
【０００４】
また、特開平７−２４３６３４号公報では、６００℃以上の高温で排ガスを直接に触媒に接触させて有害物質を除去する方法であり、ヘキサアルミネートの一部をＭｎ、Ｃｕなどの活性物質に置換された構造の触媒材料が用いられている。
【０００５】
【発明が解決しようとする課題】
しかし、特許第２６３３３１６号公報に記載された方法では、高温での蒸気圧が高いＶ２Ｏ５が触媒材料として用いられており、３００℃以下の温度領域で反応活性が大きいため、焼却炉の排ガスを冷却してから集塵し、その後に触媒による浄化を行っていたため、ガス冷却中に粉塵に付着してダイオキシンが多量に生成する問題があった。
【０００６】
特開平７−２４３６３４号公報に記載されたＭｎやＣｕ等の活性物質で一部が置換されたヘキサアルミネートからなる触媒材料は、耐熱性は有するものの、排ガス温度の５００〜８０００℃範囲での活性が十分でなく、特に５００℃以上の高温存在するダイオキシン類の前駆体を除去しにくいという問題があった。
【０００７】
したがって、本発明は、優れた耐熱性を有するとともに、高温でダイオキシン類有害物質及びその前駆体に対する分解触媒活性が高く、高温で使用可能な排ガス浄化用触媒及び排ガス浄化装置を提供することを目的としている。
【０００８】
【課題を解決するための手段】
本発明は、高温での触媒活性を示す酸化物を用いることによって、ダイオキシン及びその前駆体等の有害物質を高温においても高い効率で分解し、清浄な排ガスに変換できるという知見に基づくものであり、特に、Ｖ2Ｏ5等の酸化物と他の酸化物との複合化合物や、固溶体型複合酸化物を形成させ、融点を高めることにより高安定性を実現したものである。
【０００９】
すなわち、本発明の排ガス浄化用触媒は、Ｍｇ、Ｍｎ、Ｎｂ、Ｔａ及び周期律表第３ａ族金属から選ばれる少なくとも１種と、５価のＶとからなる複合酸化物を９７質量％以上含有する触媒材料を、チタニア担体に担持させてなることを特徴とするものである。これにより、５００〜８００℃の排ガス温度での安定性が向上し、また、Ｖ（バナジウム）の酸化価数が周囲の条件により変化するため、ダイオキシン類有害物質およびその前駆体を酸化分解する触媒効果を発現させることが可能となる。
【００１０】
特に、触媒材料は、Ｖ２Ｏ５・２ＭｎＯ、Ｖ２Ｏ５・２ＭｇＯ、Ｖ２Ｏ５・３ＭｇＯ、Ｖ２Ｏ５・Ｌｎ２Ｏ３（Ｌｎは周期律表第３ａ属元素）、Ｖ２Ｏ５・９Ｎｂ２Ｏ５及びＶ２Ｏ５・９Ｔａ２Ｏ５のうち少なくとも１種を含むことが好ましい。このように、５価のＶを含む複合酸化物は、少なくとも５００〜８００℃の範囲で高触媒活性と耐熱性を有し、高温用ダイオキシン分解触媒材料として好適に使用される。
【００１１】
さらに、本発明の高温触媒は常圧下での触媒反応温度が５００℃以上であることが好ましい。これにより、特に排ガスを冷却しない条件下で有害物質を分解する場合に高い分解効率が得られる。
【００１２】
さらにまた、本発明の高温触媒のＢＥＴ比表面積が９０ｍ2／ｇ以下であることが好ましい。高温で長期使用しても、触媒の比表面積の低下が少ないためである。
【００１３】
また、本発明の排ガス浄化装置は、排ガスを、５００℃以上の温度で請求項１乃至３のうちいずれかに記載の排ガス浄化用触媒に接触させ、前記排ガスを浄化することを特徴とするもので、これにより、排ガス中存在する有害物質を高温で除去することができる。
【００１４】
【発明の実施の形態】
本発明の排ガス浄化用触媒の触媒材料は、Ｍｇ、Ｍｎ，Ｎｂ、Ｔａ及び周期律表第３ａ族金属から選ばれる少なくとも１種と、５価のＶとを含む複合酸化物からなることが重要である。使用条件でＶの価数は２＋〜５＋と幅広く変化し、酸化触媒材料としての特性を示す活性化エネルギーが小さいため、触媒材料として適している。Ｖ２Ｏ５は単独でも触媒材料として使用可能であるが、その融点は６８０℃と低いため、５００℃以上の高温では化学的に不安定になり、寿命が著しく低下する。従って、高温触媒材料としては使用できない。
【００１５】
そこで、Ｖ2Ｏ5にＭｇ、Ｍｎ，Ｎｂ、Ｔａおよび周期律表第３ａ族金属（以下、Ｌｎで示すことがある）から選ばれる少なくとも１種の元素を特定の割合で含有させ、Ｖ2Ｏ5と上記の元素との固溶体を形成させたり、複合化合物を形成させることによって融点を１０００℃以上とすることができ、少なくとも８００℃まで十分な耐熱性を有するとともに、高い触媒活性を維持することが可能となる。
【００１６】
ここで、Ｍｇ、Ｍｎ，Ｎｂ、Ｔａおよび周期律表第３ａ族金属から選ばれる少なくとも１種の元素は、Ｖ2Ｏ5と複合酸化物を形成するものであれば、単体でも、水酸化物、酸化物、塩類等の化合物でもよい。なお、周期律表第３ａ属元素は、Ｙ及びＬａ、Ｙｂ、Ｅｒ、Ｎｄ、Ｓｍ、Ｄｙ、Ｇｄ、又はＬｕ等の希土類元素を示す。
【００１７】
また、本発明によれば、５価のＶを含む複合酸化物は、特に、Ｖ2Ｏ5・２ＭｎＯ、Ｖ2Ｏ5・２ＭｇＯ、Ｖ2Ｏ5・３ＭｇＯ、Ｖ2Ｏ5・Ｌｎ2Ｏ3（Ｌｎは周期律表第３ａ属元素）、Ｖ2Ｏ5・９Ｎｂ2Ｏ5及びＶ2Ｏ5・９Ｔａ2Ｏ5のうち少なくとも１種を含むものであることが、耐熱性及び触媒活性の点で好ましい。そして、これらの中でも特に、Ｖ2Ｏ5・２ＭｇＯ、Ｖ2Ｏ5・９Ｎｂ2Ｏ5、Ｖ2Ｏ5・Ｓｍ2Ｏ3、Ｖ2Ｏ5・Ｎｄ2Ｏ3、Ｖ2Ｏ5・Ｅｒ2Ｏ3、Ｖ2Ｏ5・Ｙｂ2Ｏ3、Ｖ2Ｏ5・Ｌｕ2Ｏ3が好ましい。
【００１８】
本発明の排ガス浄化用触媒は使用条件に応じて組成を調節し、触媒の反応温度を変更することができるが、常圧で触媒反応温度が５００℃以上であることが好ましい。また、触媒活性を考慮すると、特に６００℃以上、さらには６５０℃以上が好ましい。
【００１９】
したがって、例えば８５０℃の焼却炉の燃焼ガスが、煙道を通って触媒に接触するまでの自然冷却後に５００℃以上であるため、この排ガスを直接触媒に接触させて有毒物質を排除することができる。したがって、従来の焼却炉において必要とされた強制冷却を特に必要としなくなり、焼却システムを簡便化することができる。
【００２０】
一般に、触媒の反応効率は、触媒の比表面積に伴って高くなるが、５００℃以上の高温における比表面積の大きな触媒は、物質移動による焼結等の反応のため、時間と共に比表面積が減少するなど、触媒特性が不安定で劣化しやすくなる。従って、本発明の排ガス浄化用触媒の比表面積は９０ｍ2／ｇ以下であることが好ましく、特に５０〜９０ｍ2／ｇ、さらに６５〜８０ｍ2／ｇであることが好ましい。
【００２１】
上記の排ガス浄化用触媒を用いた本発明排ガス浄化装置は、種々の焼却炉、石炭発電、鉄鋼製錬等の高温排ガスの浄化処理に、窒素酸化物、ダイオキシン類有害物質に代表される有機ハロゲン化物、これらの有害物質を発生する前駆体を分解除去するのに使用される。本発明の触媒は高温で使用されることが重要な特徴であるため、ガスを冷却する前に微量のダイオキシン類有害物質およびダイオキシン類有害物質を発生する前駆体およびその他有害物質を分解除去し、ガス冷却中での有害物質の生成を抑制できる。
【００２２】
従って、クリーンな排ガスおよび無毒の灰塵処理を実現でき、環境負荷を大幅に軽減できる。この場合、燃焼ガスを触媒と接触させる前に脱塵処理することが好ましく、これにより触媒の劣化を効果的に防ぐことができる。
【００２３】
本発明の排ガス浄化用触媒は、公知の触媒作製方法により得ることができる。例えば、平均粒径が０．３〜５μｍのＶ2Ｏ5に対して平均粒径が０．２〜２μｍのＳｍ2Ｏ3を１：１のの割合で混合し、１１００〜１４００℃の仮焼により複合酸化物を得る。そして、上記複合酸化物と触媒担体の原料とを混合し、成形後に焼成する方法である。場合によっては、Ｖ2Ｏ5及びＳｍ2Ｏ3を仮焼せずに担体と混合、成形の後、焼成することも可能である。さらに、Ｖ2Ｏ5及びＳｍ2Ｏ3の前駆体である金属、金属酸化物粉末、固体、液体の金属塩の溶液等を用い、担体に分散させて高比表面積を有する触媒を合成することも可能である。
【００２４】
前記触媒担体としては種々の高比表面積の材質が使用されるが、Ｔｉ、Ｍｇ、Ａｌ、Ｚｒ等を主成分とした酸化物は高温排ガスの条件下でも安定性を有し、活性物質との反応による触媒の劣化が発生しにくい等の見地より好適に使用される。上記担体はハニカム、ペレット、チューブなど任意の形状に形成される。
【００２５】
【実施例】
Ｖ２Ｏ５及び表１のＮｏ．１〜１２に示す金属酸化物を添加物として表１に示す割合で混合し、表１に示す条件で仮焼した。得られた仮焼粉末をＴｉＯ２の１００体積部に対して１０体積部の割合で混合し、ペーレット状に成形した後、９００℃で焼成した。
【００２６】
また、試料Ｎｏ．１３〜１４はチタンの硫酸塩を加熱加水分解により沈殿させ、乾燥後６００℃で５時間焼成し、評価用チタニアペレットに成形した後、メタバナジン酸アンモニウム、炭酸マグネシウムおよび塩化マンガン等を用いて表１に示す組成になるように調合した。次に、硝酸及びアンモニウム液を加えて中和沈殿処理し、この沈殿物を上記チタニアペレットに含浸、担持させた。そして、表１に示す温度で仮焼し、上記チタニアペレットの気孔表面に、Ｖ２Ｏ５・３ＭｇＯ及びＶ２Ｏ５・２ＭｎＯをそれぞれ形成した。この時、触媒担持量は、チタニア１００体積部に対して１．７〜２．５体積部であった。
【００２７】
さらに、試料Ｎｏ．１５は本発明の触媒材料がない場合の比較例である。
【００２８】
なお、得られた触媒中に低融点のＶ2Ｏ5が残存しないように、調合組成には目標の化合物の組成よりもＶを不足になるように調整した。
【００２９】
触媒は、測定用として２０φ×２０ｍｍのペレット状に加工した。
【００３０】
得られた触媒材料の結晶相をＸ線回折によって調べ、主結晶相を表１に示した。いずれも９５質量％以上が主結晶相であり、残部は過剰に加えた金属酸化物であった。触媒の比表面積は水銀圧入法により測定した。
【００３１】
得られた試料の触媒分解特性を、図１に示す試験装置を用いて評価した。試験装置は、ヒータ１内に反応管２が設けられており、その中に触媒３が充填されている。加熱炉１を６００℃、７００℃及び８００℃に設定し、それぞれの温度でガス導入管４から試験用ガスを導入し、ガス排気管５から排出されるガスを冷却部６で冷却した。そして、冷却されたガスのダイオキシン濃度をＨＲＧＣ／ＨＲＭＳ法により測定した。
【００３２】
なお、試験用ガスは通常の家庭ゴミを焼却する時の燃焼ガスを回収したものである。また、試験用ガスの流速ＳＶは９０００／ｈにした。結果を表１に示した。
【００３３】
【表１】
本発明の試料Ｎｏ．１〜１４は、触媒材料の主結晶相の融点が１０００℃以上であり、本発明の触媒材料を設けないＮｏ．１５に対して６００℃以上の排ガス温度で高いダイオキシン除去率を示し、冷却後の排ガス中のダイオキシン濃度は０．１ｎｇＴＥＱ／Ｎｍ３以下であった。
【００３５】
一方、ＷＯ３とＶ２Ｏ５との混合物で、通常の低温用触媒材料で本発明の範囲外の試料Ｎｏ．１５は、６００℃以上の温度ではダイオキシン濃度が０．６２ｎｇＴＥＱ／Ｎｍ３以上となり、触媒活性が低かった。
【００３６】
また、Ｆｅ2Ｏ3とＶ2Ｏ5との複合酸化物で、本発明の範囲外の試料Ｎｏ．１６は、８７０℃と低融点の主結晶相を有しているため、６００℃以上で０．１３４ｎｇＴＥＱ／Ｎｍ3以上、特に７００℃以上ではダイオキシン濃度が１．１５ｎｇＴＥＱ／Ｎｍ3以上となり、触媒活性が低かった。
【００３７】
【発明の効果】
本発明の排ガス浄化用触媒は、高温において安定性と触媒活性とが高く、ダイオキシン及びその前駆体等の有害物質を高温においても高い効率で分解することができ、排ガス及び粉塵中の有害物質濃度を低減し、環境保護に寄与できる。
【図面の簡単な説明】
【図１】実施例で用いた触媒の試験装置の概略断面図である。
【符号の説明】
１・・・ヒータ
２・・・反応管
３・・・触媒
４・・・ガス導入管
５・・・ガス排気管
６・・・冷却部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust gas purifying catalyst and an exhaust gas purifying device, and in particular, an exhaust gas purifying catalyst for decomposing and removing harmful substances such as dioxin organochlorine compounds and precursors thereof such as aromatic hydrocarbon compounds generated from an incinerator. And an exhaust gas purification apparatus using the same.
[0002]
[Prior art]
Organochlorine compounds are known to be harmful to the human body, and in recent years, the generation of highly toxic dioxins that are highly toxic has been pointed out by incineration of waste, which has become a serious social problem as an environmental problem. . Therefore, various methods have been proposed for removing dioxins and harmful substances.
[0003]
Examples of methods for removing dioxins harmful substances include adsorption removal to adsorbents, combustion decomposition at high temperatures, and the like. In recent years, decomposition removal of dioxins harmful substances using a catalyst has been proposed. In this method, for example, in Japanese Patent No. 2633316, after the combustion exhaust gas is cooled by a gas cooling tower, the dust is removed by an electric dust collector, and V 2 O 5 is added to the titanium oxide carrier at a temperature of 150 to 290 ° C. The organochlorine compound in the exhaust gas is decomposed by contacting with a catalyst supporting WO 3 .
[0004]
Japanese Patent Laid-Open No. 7-243634 discloses a method for removing harmful substances by directly contacting exhaust gas with a catalyst at a high temperature of 600 ° C. or higher, and converting a part of hexaaluminate into an active substance such as Mn and Cu. A catalyst material having a substituted structure is used.
[0005]
[Problems to be solved by the invention]
However, in the method described in Japanese Patent No. 2633316, V 2 O 5 having a high vapor pressure at a high temperature is used as a catalyst material , and the reaction activity is large in a temperature range of 300 ° C. or lower. Since dust was collected after the exhaust gas was cooled and then purified by a catalyst, there was a problem that a large amount of dioxin was generated by adhering to the dust during gas cooling.
[0006]
A catalyst material made of hexaaluminate partially substituted with an active substance such as Mn and Cu described in JP-A-7-243634 has heat resistance, but has an exhaust gas temperature in the range of 500 to 8000 ° C. There was a problem that the activity was not sufficient, and it was difficult to remove dioxin precursors present at a high temperature of 500 ° C. or more.
[0007]
Accordingly, an object of the present invention is to provide an exhaust gas purifying catalyst and an exhaust gas purifying apparatus that have excellent heat resistance, have high decomposition catalytic activity for dioxins harmful substances and their precursors at high temperatures, and can be used at high temperatures. It is said.
[0008]
[Means for Solving the Problems]
The present invention is based on the knowledge that by using an oxide exhibiting catalytic activity at high temperatures, harmful substances such as dioxins and their precursors can be decomposed with high efficiency even at high temperatures and converted into clean exhaust gas. In particular, high stability is realized by forming a compound compound of an oxide such as V 2 O 5 and another oxide or a solid solution type complex oxide and increasing the melting point.
[0009]
That is, the exhaust gas purifying catalyst of the present invention contains 97% by mass or more of a composite oxide composed of at least one selected from Mg, Mn, Nb, Ta and Group 3a metal of the periodic table and pentavalent V. The catalyst material is supported on a titania carrier . As a result, the stability at an exhaust gas temperature of 500 to 800 ° C. is improved, and the oxidation valence of V (vanadium) varies depending on the surrounding conditions, so that the catalyst decomposes oxidatively decomposing dioxins and their precursors. An effect can be expressed.
[0010]
In particular, catalytic material, V 2 O 5 · 2MnO, V 2
[0011]
Furthermore, the high temperature catalyst of the present invention preferably has a catalytic reaction temperature of 500 ° C. or higher under normal pressure. As a result, high decomposition efficiency can be obtained particularly when the harmful substances are decomposed under conditions where the exhaust gas is not cooled.
[0012]
Furthermore, it is preferable that the BET specific surface area of the high-temperature catalyst of the present invention is 90 m 2 / g or less. This is because the specific surface area of the catalyst is little lowered even when used for a long time at a high temperature.
[0013]
The exhaust gas purifying apparatus of the present invention is characterized in that exhaust gas is brought into contact with the exhaust gas purifying catalyst according to any one of
[0014]
DETAILED DESCRIPTION OF THE INVENTION
It is important that the catalyst material of the exhaust gas purifying catalyst of the present invention comprises a composite oxide containing at least one selected from Mg, Mn, Nb, Ta and Group 3a metal of the periodic table and pentavalent V. It is. The valence of V varies widely from 2+ to 5+ under the use conditions, and the activation energy showing the characteristics as an oxidation catalyst material is small, so it is suitable as a catalyst material . V 2 O 5 can be used alone as a catalyst material , but since its melting point is as low as 680 ° C., it becomes chemically unstable at a high temperature of 500 ° C. or more, and the life is remarkably reduced. Therefore, it cannot be used as a high temperature catalyst material .
[0015]
Therefore, V 2 O 5 contains at least one element selected from Mg, Mn, Nb, Ta and Group 3a metal of the periodic table (hereinafter sometimes referred to as Ln) in a specific ratio, and V 2 By forming a solid solution of O 5 and the above element or forming a composite compound, the melting point can be raised to 1000 ° C. or higher, and it has sufficient heat resistance up to at least 800 ° C. and maintains high catalytic activity. It becomes possible.
[0016]
Here, at least one element selected from Mg, Mn, Nb, Ta, and Group 3a metal of the periodic table may be a simple substance or a hydroxide as long as it forms a composite oxide with V 2 O 5. Further, compounds such as oxides and salts may be used. The group 3a element of the periodic table indicates Y and rare earth elements such as La, Yb, Er, Nd, Sm, Dy, Gd, or Lu.
[0017]
Further, according to the present invention, a composite oxide containing pentavalent V is in particular, V 2 O 5 · 2MnO, V 2
[0018]
The exhaust gas-purifying catalyst of the present invention can be adjusted in composition according to the conditions of use to change the reaction temperature of the catalyst, but the catalyst reaction temperature is preferably 500 ° C. or higher at normal pressure. In consideration of the catalytic activity, 600 ° C. or higher, more preferably 650 ° C. or higher is preferable.
[0019]
Therefore, for example, since the combustion gas of an incinerator at 850 ° C. is 500 ° C. or higher after natural cooling until it contacts the catalyst through the flue, this exhaust gas can be directly contacted with the catalyst to eliminate toxic substances. it can. Therefore, the forced cooling required in the conventional incinerator is not particularly required, and the incineration system can be simplified.
[0020]
In general, the reaction efficiency of a catalyst increases with the specific surface area of the catalyst. However, a catalyst with a large specific surface area at a high temperature of 500 ° C. or more has a specific surface area that decreases with time due to a reaction such as sintering by mass transfer. The catalyst characteristics are unstable and easily deteriorate. Therefore, the specific surface area of the exhaust gas purifying catalyst of the present invention is preferably at most 90m 2 / g, it is particularly preferably 50~90m 2 / g, further 65~80m 2 / g.
[0021]
The exhaust gas purification apparatus of the present invention using the exhaust gas purification catalyst described above is an organic halogen represented by nitrogen oxides and dioxins harmful substances for purification treatment of high temperature exhaust gas such as various incinerators, coal power generation, and steel smelting. Is used to decompose and remove precursors that generate these harmful substances. Since it is an important feature that the catalyst of the present invention is used at a high temperature, a trace amount of dioxins harmful substances and precursors that generate dioxins harmful substances and other harmful substances are decomposed and removed before cooling the gas, Generation of harmful substances during gas cooling can be suppressed.
[0022]
Therefore, clean exhaust gas and non-toxic ash dust treatment can be realized, and the environmental load can be greatly reduced. In this case, it is preferable to perform a dust removal treatment before the combustion gas is brought into contact with the catalyst, whereby the deterioration of the catalyst can be effectively prevented.
[0023]
The exhaust gas purifying catalyst of the present invention can be obtained by a known catalyst preparation method. For example, Sm 2 O 3 having an average particle diameter of 0.2 to 2 μm is mixed with V 2 O 5 having an average particle diameter of 0.3 to 5 μm at a ratio of 1: 1, and a temporary temperature of 1100 to 1400 ° C. is mixed. A composite oxide is obtained by calcination. And it is the method of mixing the said complex oxide and the raw material of a catalyst carrier, and baking after shaping | molding. In some cases, V 2 O 5 and Sm 2 O 3 may be calcined after being mixed with a carrier without being calcined and molded. Furthermore, a metal having a high specific surface area is synthesized by dispersing it in a support using a metal, metal oxide powder, solid or liquid metal salt solution, which is a precursor of V 2 O 5 and Sm 2 O 3. Is also possible.
[0024]
As the catalyst carrier, materials having various high specific surface areas are used. However, oxides mainly composed of Ti, Mg, Al, Zr, etc. are stable under high temperature exhaust gas conditions, It is preferably used from the standpoint that it is difficult for the catalyst to deteriorate due to the reaction. The carrier is formed in an arbitrary shape such as a honeycomb, a pellet, or a tube.
[0025]
【Example】
V 2 O 5 and No. 1 in Table 1. Were mixed in indicates to percentage in Table 1 as an additive metal oxide shown in 1-12, and calcined under the conditions shown in Table 1. The obtained calcined powder was mixed at a ratio of 10 parts by volume with respect to 100 parts by volume of TiO 2 , molded into a pellet shape, and then fired at 900 ° C.
[0026]
Sample No. 13-14 precipitated by thermal hydrolysis of sulfates of titanium, 600 was fired ℃ for 5 hours after drying, after forming the titania pellets for evaluation, using ammonium metavanadate, magnesium carbonate, and manganese chloride The composition shown in Table 1 was prepared. Then neutralized precipitation treatment by addition of nitric acid and ammonium solution, impregnating the precipitate on the titania pellets was supported. Then, calcined at a temperature shown in Table 1, the pores the surface of the titania pellets was formed V 2 O 5 · 3MgO and V 2 O 5 · 2MnO respectively. At this time, the amount of the catalyst supported was 1.7 to 2.5 parts by volume with respect to 100 parts by volume of titania.
[0027]
Furthermore, sample no. 15 is a comparative example in the case where there is no catalyst material of the present invention .
[0028]
Note that in the resultant catalyst to the low melting point V 2 O 5 in does not remain, the formulated composition was adjusted to the lack of V than the composition of the target compound.
[0029]
The catalyst was processed into a 20φ × 20 mm pellet for measurement.
[0030]
The crystal phase of the obtained catalyst material was examined by X-ray diffraction, and the main crystal phase is shown in Table 1. In both cases, 95% by mass or more was the main crystal phase, and the balance was an excessively added metal oxide. The specific surface area of the catalyst was measured by mercury porosimetry.
[0031]
The catalytic decomposition characteristics of the obtained samples were evaluated using the test apparatus shown in FIG. In the test apparatus, a
[0032]
The test gas is obtained by collecting the combustion gas when incinerating ordinary household waste. The flow rate SV of the test gas was 9000 / h. The results are shown in Table 1.
[0033]
[Table 1]
Sample No. of the present invention. 1-14, the melting point of the main crystal phase of the catalyst material is at 1000 ° C. or higher, without the catalyst material of the present invention No. 15 showed a high dioxin removal rate at an exhaust gas temperature of 600 ° C. or higher, and the dioxin concentration in the exhaust gas after cooling was 0.1 ngTEQ / Nm 3 or less.
[0035]
On the other hand, it is a mixture of WO 3 and V 2 O 5 and is a normal low-temperature catalyst material , and sample No. No. 15 had a dioxin concentration of 0.62 ng TEQ / Nm 3 or higher at a temperature of 600 ° C. or higher, and the catalytic activity was low.
[0036]
Further, it is a composite oxide of Fe 2 O 3 and V 2 O 5, and sample No. No. 16 has a main crystal phase with a low melting point of 870 ° C., so that the catalyst activity is 0.134 ngTEQ / Nm 3 or higher at 600 ° C. or higher, and particularly 1.700 ngTEQ / Nm 3 or higher at 700 ° C. or higher. Was low.
[0037]
【The invention's effect】
The exhaust gas purifying catalyst of the present invention has high stability and catalytic activity at high temperatures, can decompose dioxins and their precursors with high efficiency even at high temperatures, and concentration of harmful substances in exhaust gases and dusts Can contribute to environmental protection.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a catalyst testing apparatus used in Examples.
[Explanation of symbols]
DESCRIPTION OF
Claims (5)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000228440A JP4730998B2 (en) | 2000-07-28 | 2000-07-28 | Exhaust gas purification catalyst and exhaust gas purification device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000228440A JP4730998B2 (en) | 2000-07-28 | 2000-07-28 | Exhaust gas purification catalyst and exhaust gas purification device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2002035582A JP2002035582A (en) | 2002-02-05 |
| JP4730998B2 true JP4730998B2 (en) | 2011-07-20 |
Family
ID=18721722
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000228440A Expired - Fee Related JP4730998B2 (en) | 2000-07-28 | 2000-07-28 | Exhaust gas purification catalyst and exhaust gas purification device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4730998B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114225930B (en) * | 2021-12-23 | 2024-03-29 | 广东誉谱检测科技有限公司 | Composite material for decomposing dioxin and preparation method and application thereof |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3085178B2 (en) * | 1994-12-30 | 2000-09-04 | 堺化学工業株式会社 | Catalyst and method for treating exhaust gas |
| JP3826161B2 (en) * | 1995-06-08 | 2006-09-27 | 株式会社 日本触媒 | Vanadium-containing catalyst, method for producing the same, and method for using the same |
| JP3785558B2 (en) * | 1997-11-27 | 2006-06-14 | バブコック日立株式会社 | Organochlorine compound removal catalyst and organochlorine compound removal method |
| JPH11216361A (en) * | 1998-01-30 | 1999-08-10 | Toshiba Corp | Decomposition catalyst of organic halogenide, decomposition device for organic halogenide and method of decomposition organic halogenide |
| JP3212577B2 (en) * | 1998-06-19 | 2001-09-25 | 三菱重工業株式会社 | Exhaust gas treatment catalyst, exhaust gas treatment method and treatment apparatus |
-
2000
- 2000-07-28 JP JP2000228440A patent/JP4730998B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2002035582A (en) | 2002-02-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3589529B2 (en) | Method and apparatus for treating flue gas | |
| JP3326836B2 (en) | Catalyst body and method for producing catalyst body | |
| JP4113090B2 (en) | Exhaust gas treatment method | |
| NO334050B1 (en) | Catalyst for the decomposition of N <N> 2 </N> O, its use as well as process for its preparation | |
| JP2000197822A (en) | Catalyst for decomposing and removing nitrogen oxide and method for decomposing and removing nitrogen oxide | |
| CN1327966C (en) | Process for preparing fluorine blended metal oxide catalyst | |
| JP4730998B2 (en) | Exhaust gas purification catalyst and exhaust gas purification device | |
| JP4424653B2 (en) | Gaseous mercury removing agent, method for producing the same, and gaseous mercury removing method | |
| JP2001079346A (en) | Method and device for treating gas and method for regenerating honeycomb activated carbon | |
| JP2002529225A (en) | Catalyst body and method for reducing halogenated hydrocarbons | |
| JP2001286734A (en) | Method for decomposing chlorinated organic compound and method for treating combustion exhaust gas | |
| KR100382050B1 (en) | Catalyst for Removing Dioxin and Nitrogen Oxides in Flue Gas and Method for Treating Combustion Exhaust Gases Using the Same | |
| JP2004066009A (en) | Carbon material and equipment for treating flue gas | |
| JP2007283209A (en) | Gasification catalyst, its manufacturing method and gasification system | |
| JP3868705B2 (en) | Combustion exhaust gas treatment method | |
| JP2008126103A (en) | Oxidation catalyst for removing fine particulate substance in exhaust gas, and removing method of fine particulate substance using the same | |
| TWI411470B (en) | Catalyst for regenerative catalytic oxidizer, method for producing the same and method for treating volatile organic compounds | |
| JP2004290753A (en) | Heat-resistant denitrification catalyst | |
| JP2010051867A (en) | Filter for cleaning exhaust gas | |
| JPH11300160A (en) | Waste incinerating device and waste incinerating method | |
| JP5541843B2 (en) | Composite oxide for exhaust gas purification catalyst and exhaust gas purification filter using the same | |
| JP4169235B2 (en) | N2O emission reduction method from incinerator | |
| JP2019136632A (en) | Combustion catalyst | |
| JP2001286729A (en) | Method for decomposing chlorinated organic compound and method for treating combustion exhaust gas | |
| JP3920332B2 (en) | Catalyst for the decomposition of organic compounds in gas mixtures |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20070618 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20090617 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20090901 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20091029 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20091208 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20100205 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20110322 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20110419 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140428 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| LAPS | Cancellation because of no payment of annual fees |