JPH09253506A - Carrier for nox reducing catalyst - Google Patents
Carrier for nox reducing catalystInfo
- Publication number
- JPH09253506A JPH09253506A JP8093059A JP9305996A JPH09253506A JP H09253506 A JPH09253506 A JP H09253506A JP 8093059 A JP8093059 A JP 8093059A JP 9305996 A JP9305996 A JP 9305996A JP H09253506 A JPH09253506 A JP H09253506A
- Authority
- JP
- Japan
- Prior art keywords
- reduction catalyst
- carrier
- brown
- catalyst
- pores
- 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.)
- Pending
Links
- 239000003054 catalyst Substances 0.000 title claims abstract description 72
- 230000001603 reducing effect Effects 0.000 title abstract description 8
- 239000000919 ceramic Substances 0.000 claims abstract description 27
- 239000011148 porous material Substances 0.000 claims abstract description 15
- 239000000463 material Substances 0.000 claims abstract description 6
- 229910052751 metal Inorganic materials 0.000 claims description 13
- 239000002184 metal Substances 0.000 claims description 13
- 239000000843 powder Substances 0.000 claims description 10
- 229910052788 barium Inorganic materials 0.000 claims description 9
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims description 8
- 229910052727 yttrium Inorganic materials 0.000 claims description 8
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 claims description 7
- 239000006260 foam Substances 0.000 claims description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 4
- 230000002950 deficient Effects 0.000 claims description 3
- 229910052692 Dysprosium Inorganic materials 0.000 claims description 2
- 229910052691 Erbium Inorganic materials 0.000 claims description 2
- 229910017052 cobalt Inorganic materials 0.000 claims description 2
- 239000010941 cobalt Substances 0.000 claims description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 2
- KBQHZAAAGSGFKK-UHFFFAOYSA-N dysprosium atom Chemical compound [Dy] KBQHZAAAGSGFKK-UHFFFAOYSA-N 0.000 claims description 2
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 229910052746 lanthanum Inorganic materials 0.000 claims description 2
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 239000000203 mixture Substances 0.000 abstract description 9
- 238000004519 manufacturing process Methods 0.000 abstract description 7
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 abstract description 6
- 238000000034 method Methods 0.000 abstract description 5
- NGDQQLAVJWUYSF-UHFFFAOYSA-N 4-methyl-2-phenyl-1,3-thiazole-5-sulfonyl chloride Chemical compound S1C(S(Cl)(=O)=O)=C(C)N=C1C1=CC=CC=C1 NGDQQLAVJWUYSF-UHFFFAOYSA-N 0.000 abstract description 2
- ITHZDDVSAWDQPZ-UHFFFAOYSA-L barium acetate Chemical compound [Ba+2].CC([O-])=O.CC([O-])=O ITHZDDVSAWDQPZ-UHFFFAOYSA-L 0.000 abstract description 2
- 229910010293 ceramic material Inorganic materials 0.000 abstract 3
- 208000007542 Paresis Diseases 0.000 abstract 1
- 229920002678 cellulose Polymers 0.000 abstract 1
- 239000001913 cellulose Substances 0.000 abstract 1
- 238000000151 deposition Methods 0.000 abstract 1
- 208000012318 pareses Diseases 0.000 abstract 1
- 238000006722 reduction reaction Methods 0.000 description 50
- 239000007789 gas Substances 0.000 description 21
- 239000011259 mixed solution Substances 0.000 description 11
- 229910052878 cordierite Inorganic materials 0.000 description 9
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 9
- 238000010304 firing Methods 0.000 description 6
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 6
- 239000007864 aqueous solution Substances 0.000 description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- AYJRCSIUFZENHW-UHFFFAOYSA-L barium carbonate Chemical compound [Ba+2].[O-]C([O-])=O AYJRCSIUFZENHW-UHFFFAOYSA-L 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 229910000510 noble metal Inorganic materials 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- WWNBZGLDODTKEM-UHFFFAOYSA-N sulfanylidenenickel Chemical group [Ni]=S WWNBZGLDODTKEM-UHFFFAOYSA-N 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonium chloride Substances [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- 244000191761 Sida cordifolia Species 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 235000011114 ammonium hydroxide Nutrition 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 239000002562 thickening agent Substances 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- DNWJQQMQDATZMU-UHFFFAOYSA-N 2-hydroxypropane-1,2,3-tricarboxylic acid;yttrium Chemical compound [Y].OC(=O)CC(O)(C(O)=O)CC(O)=O DNWJQQMQDATZMU-UHFFFAOYSA-N 0.000 description 1
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 description 1
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 229910021536 Zeolite Inorganic materials 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O ammonium group Chemical group [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 150000001553 barium compounds Chemical class 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 229910000420 cerium oxide Inorganic materials 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052953 millerite Inorganic materials 0.000 description 1
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 description 1
- SIWVEOZUMHYXCS-UHFFFAOYSA-N oxo(oxoyttriooxy)yttrium Chemical compound O=[Y]O[Y]=O SIWVEOZUMHYXCS-UHFFFAOYSA-N 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229920001568 phenolic resin Polymers 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 229910001404 rare earth metal oxide Inorganic materials 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 230000000392 somatic effect Effects 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- QEMXHQIAXOOASZ-UHFFFAOYSA-N tetramethylammonium Chemical compound C[N+](C)(C)C QEMXHQIAXOOASZ-UHFFFAOYSA-N 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- -1 yttrium compound Chemical class 0.000 description 1
- 239000010457 zeolite Substances 0.000 description 1
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】この発明は、エンジンの排気
ガス中に含まれるＮＯX を還元して排気ガスを浄化する
ＮＯX 還元触媒の担持体に関する。TECHNICAL FIELD The present invention relates to carrier of the NO X reduction catalyst by reducing NO X contained in the exhaust gas of the engine to purify the exhaust gas.
【０００２】[0002]
【従来の技術】従来、ＮＯX 分解触媒として、接触還元
と直接分解の触媒が知られており、ガソリンエンジンで
は、白金、ロジウムを触媒とし、還元剤として、排気ガ
ス中のＨＣ，ＣＯ，Ｈ2 を使用する３元触媒が知られて
いる。しかしながら、３元触媒は、アルミナ、ゼオライ
ト或いはこれらの担体に貴金属を担持したものである
が、酸素過剰の希薄燃焼領域即ちリーンバーン領域やデ
ィーゼルエンジンでは、ＮＯX の還元率が低く、３元触
媒はディーゼルエンジンから排気される排気ガスの浄化
には有効でなかった。即ち、ディーゼルエンジンでは、
空気過剰で燃焼されるので排気ガス中にＯ2 が存在し、
窒素酸化物ＮＯX が多量に排出される。これに対して、
ガソリンエンジンでは理論混合比で燃焼され、排気ガス
中にはＯ2 が余り存在せず、エンジン後流に設けられた
還元触媒によりＮＯが分解されるので、ＮＯX の問題が
ない。従来、ディーゼルエンジンから窒素酸化物ＮＯX
が外部に排出されるのを抑制するため、種々の触媒を組
み込んだディーゼルパティキュレートフィルタが知られ
ている。ところが、ディーゼルエンジンの排気ガスは、
Ｏ2 が多量に含まれているため、触媒が機能しない欠点
があった。2. Description of the Related Art Conventionally, catalysts for catalytic reduction and direct decomposition are known as NO X decomposition catalysts. In gasoline engines, platinum, rhodium are used as catalysts, and HC, CO, H in exhaust gas are used as reducing agents. Three-way catalysts using 2 are known. However, although a three-way catalyst is one in which a noble metal is supported on alumina, zeolite, or a carrier thereof, the NO x reduction rate is low in a lean burn region with excess oxygen, that is, a lean burn region or a diesel engine, and the three-way catalyst is low. Was not effective in purifying the exhaust gas emitted from diesel engines. That is, in a diesel engine,
Since it is burned with excess air, O 2 is present in the exhaust gas,
Nitrogen oxides NO X is a large amount of discharge. On the contrary,
In gasoline engines are burned in stoichiometric, the exhaust gas does not exist remainder O 2, since NO is decomposed by reduction catalyst provided in flow after the engine, there is no of the NO X problems. Conventionally, from diesel engines nitrogen oxides NO x
Diesel particulate filters incorporating various catalysts have been known in order to suppress the emission of hydrogen to the outside. However, the exhaust gas of a diesel engine is
Since the catalyst contains a large amount of O 2 , it has a drawback that the catalyst does not function.
【０００３】そこで、上記のようなディーゼルエンジン
や希薄燃焼領域即ちリーンバーン領域でのＮＯX の浄化
に対しては、ペロブスカイト系の触媒の開発がされてい
るが、ＮＯX の還元率が低いという問題があった（例え
ば、特開平６−１００３１９号公報、特開平６−３１５
６３４号公報参照）。また、特開昭６３−７７５４３号
公報に開示された排気ガス浄化用触媒は、触媒担体と、
該触媒担体表面に担持されたアルカリ土類金属の酸化
物、酸化ランタン及び酸化セリウムから成るペロブスカ
イト型複合酸化物及び貴金属触媒成分とを含むものであ
る。更に、特開昭６３−７７５４３号公報に開示された
排気ガス浄化用触媒は、表面にペロブスカイト型複合酸
化物とＯ2 ストレージ性希土類酸化物を含む層を設けた
触媒担体に、触媒成分としてＰｄ又はＰｄと他の貴金属
を担持させたものである。Therefore, for purifying NO X in the diesel engine and the lean burn region, that is, the lean burn region as described above, a perovskite catalyst has been developed, but it is said that the NO X reduction rate is low. There was a problem (for example, Japanese Patent Laid-Open Nos. 6-100319 and 6-315).
634). Further, the exhaust gas purifying catalyst disclosed in Japanese Patent Application Laid-Open No. 63-77543 includes a catalyst carrier,
It comprises a perovskite-type composite oxide composed of an oxide of an alkaline earth metal, lanthanum oxide and cerium oxide supported on the surface of the catalyst carrier, and a noble metal catalyst component. Further, the exhaust gas purifying catalyst disclosed in JP-A-63-77543 has Pd as a catalyst component on a catalyst carrier having a layer containing a perovskite complex oxide and an O 2 storage rare earth oxide on the surface. Alternatively, Pd and another noble metal are supported.
【０００４】[0004]
【発明が解決しようとする課題】上記のような現状に鑑
みて、いろいろな触媒が検討されたが、ＮＯX を還元す
る触媒として、その中で還元剤を必要としない直接還元
分解するブラウンミラーライト型構造を有する化合物、
例えば、Ｂａ3 Ｙ4 Ｏ9 やＢａＬａ2 Ｏ4 の化合物があ
る。In view of the situation as described above [0005], various the catalyst has been studied, as a catalyst for reducing NO X, directly reducing and decomposing Brown mirrors that do not require a reducing agent therein A compound having a light type structure,
For example, there are compounds of Ba 3 Y 4 O 9 and BaLa 2 O 4 .
【０００５】一般式Ａ2 Ｂ2 Ｏ5 （但し、Ａは２価の金
属、Ｂは３価の金属）を持つブラウンミラライト型構造
を有するＮＯX 還元触媒は、金属の炭酸塩や酸化物を１
４００℃程度の高温で合成していた。このため、原料の
作製中に、原料の混合が均一にならず、合成時の焼成収
縮により触媒表面は小さくなる等の欠点を有する。その
ため、ブラウンミラライト型構造を有するＮＯX 還元触
媒がＮＯX を直接還元させることができるが、実用化が
困難であった。NO x reduction catalysts having a Brown-Millalite structure having the general formula A 2 B 2 O 5 (where A is a divalent metal and B is a trivalent metal) are metal carbonates and oxides. 1
It was synthesized at a high temperature of about 400 ° C. Therefore, during the production of the raw materials, there are drawbacks such that the raw materials are not uniformly mixed, and the catalyst surface becomes small due to firing shrinkage during synthesis. Therefore, the NO x reduction catalyst having the brown-milarite type structure can directly reduce NO x , but it was difficult to put it into practical use.
【０００６】[0006]
【課題を解決するための手段】この発明の主たる目的
は、ディーゼルエンジンの燃焼室から排出される排気ガ
ス中のＮＯX を還元して浄化するため、担持体として微
細な空孔を有する基本構造体を用い、基本構造体の空孔
中に、低温で焼成したブラウンミラーライト型構造を有
するＮＯX 還元触媒を担持し、更に、ブラウンミラーラ
イト型構造を有するＮＯX 還元触媒がバリウムやイット
リウムの触媒金属の硝酸塩や酢酸塩の水溶液にクエン酸
を加え、更にカルボメチルセルロース等の増粘材を加
え、これを加熱して水分を蒸発させ、或いは、アンモニ
ア水溶液やテトラメチルアンモニウム等で沈殿させ、加
熱して水分を蒸発させ、その後、５００℃〜９００℃の
低温で焼成することによって、従来のブラウンミラライ
ト型構造の比表面積を飛躍的に大きくしたＮＯX 還元触
媒の担持体を提供することである。The main purpose of the Means for Solving the Problems] The present invention, for cleaning by reducing NO X in the exhaust gas discharged from the combustion chamber of a diesel engine, the basic structure having fine pores as a support using somatic, in pores of the basic structure, carries the NO X reduction catalyst having a brown mirror light type structure was sintered at a low temperature, and further, NO X reduction catalyst having a brown mirror light type structure of barium and yttrium Citric acid is added to an aqueous solution of a nitrate or acetate of a catalytic metal, and a thickener such as carbomethylcellulose is further added, and this is heated to evaporate water, or precipitated by an aqueous ammonia solution or tetramethylammonium, and heated. To evaporate the water content, and then to bake at a low temperature of 500 ° C to 900 ° C to increase the specific surface area of the conventional brown millerite structure. To provide a carrier to increase the NO X reduction catalyst.
【０００７】この発明は、ハニカムセラミックス、フォ
ーム状金属やセラミックス及びフェルト状セラミックス
繊維体から選択される材料によって作製された基本構造
体の空孔中に、一般式Ａ2 Ｂ2 Ｏ5 を持つブラウンミラ
ライト型構造を有するＮＯX還元触媒が担持され、Ａの
位置にバリウムを且つＢの位置にイットリウムを有し、
Ｂａ3 Ｙ4 Ｏ9 の基本構造に比べてＢａＯ分の欠損部分
を有することを特徴とするＮＯX 還元触媒の担持体に関
する。ここで、一般式Ａ2 Ｂ2 Ｏ5 におけるＡは２価の
金属であり、また、Ｂは３価の金属である。The present invention provides a brown structure having the general formula A 2 B 2 O 5 in the pores of a basic structure made of a material selected from honeycomb ceramics, foam metal or ceramics, and felt ceramics fibrous bodies. A NO x reduction catalyst having a Miralite type structure is supported, barium is present at position A and yttrium is present at position B,
The present invention relates to a carrier for a NO x reduction catalyst, which has a deficient portion of BaO as compared with the basic structure of Ba 3 Y 4 O 9 . Here, A in the general formula A 2 B 2 O 5 is a divalent metal, and B is a trivalent metal.
【０００８】また、このＮＯX 還元触媒の担持体では、
前記ブラウンミラライト型構造を持つ前記ＮＯX 還元触
媒は、そのＹ／Ｂａの比が１．１〜１．４の範囲にあ
る。更に、前記ブラウンミラライト型構造を持つ前記Ｎ
ＯX 還元触媒の粉末の比表面積は、１．５ｍ2 ／ｇ以上
である。Further, in the carrier of this NO x reduction catalyst,
The NO X reduction catalyst having the brownmillerite type structure, the ratio of Y / Ba is in the range of 1.1 to 1.4. Further, the N having the brown mirror light type structure
The specific surface area of the powder of the O x reduction catalyst is 1.5 m 2 / g or more.
【０００９】また、このＮＯX 還元触媒の担持体では、
前記ブラウンミラライト型構造を持つ前記Ｂａ3 Ｙ4 Ｏ
9 の構造は、そのバリウムの位置の１分子以下の量をニ
ッケル、コバルト、鉄の少なくとも１種に変えたもので
ある。或いは、前記ブラウンミラライト型構造を持つ前
記Ｂａ3 Ｙ4 Ｏ9 の構造は、そのイットリウムの位置の
１分子以下の量をランタン、エルビュウム、ディスプロ
シウムの少なくとも１種で一部を置換したものである。
このように、前記ブラウンミラライト型構造の一部を置
換することで格子の歪みが生じ、活性が増大し、且つ耐
久性も良化される。Further, in the carrier of this NO x reduction catalyst,
The Ba 3 Y 4 O having the brown mirror light type structure
The structure of 9 is such that the amount of one molecule or less at the barium position is changed to at least one of nickel, cobalt and iron. Alternatively, the structure of the Ba 3 Y 4 O 9 having the brown-milarite type structure is one in which the amount of one molecule or less at the yttrium position is partially replaced with at least one of lanthanum, erbium and dysprosium. Is.
As described above, by substituting a part of the Brown-Millerite structure, distortion of the lattice occurs, the activity is increased, and the durability is improved.
【００１０】このＮＯX 還元触媒の担持体は、上記のよ
うに、基本構造体の空孔中に一般式Ａ2 Ｂ2 Ｏ5 のブラ
ウンミラライト型構造を有するＮＯX 還元触媒を担持さ
せ、Ａの位置にバリウムを且つＢの位置にイットリウム
を有し、Ｂａ3 Ｙ4 Ｏ9 の基本構造に比べてＢａＯ分の
欠損部分を有し、低温で焼成できるので、比表面積を大
幅に大きくすることができ、ＮＯX の還元率を高くする
ことができ、工業的価値が大きいものとなる。また、こ
のＮＯX 還元触媒の担持体は、焼成温度によって比表面
積をコントロールすることができるものである。従っ
て、このＮＯX 還元触媒の担持体にディーゼルエンジン
から排気される排気ガスを接触させると、無秩序化した
酸素欠陥が活性化する範囲の高温になるので、排気ガス
中に存在するＮＯX が前記触媒で還元され、ＮＯX の還
元作用を常に高く維持でき、ＮＯX還元率を向上させ、
それによって排気ガス中のＮＯX の存在量を低減でき
る。As described above, the carrier for the NO x reduction catalyst has the pores of the basic structure loaded with the NO x reduction catalyst having the Brownmillerite type structure represented by the general formula A 2 B 2 O 5 . It has barium at position A and yttrium at position B, has a BaO deficient portion compared to the basic structure of Ba 3 Y 4 O 9 , and can be fired at a low temperature, thus significantly increasing the specific surface area. In addition, the reduction rate of NO x can be increased and the industrial value becomes great. Moreover, the specific surface area of the NO X reduction catalyst carrier can be controlled by the firing temperature. Therefore, when the exhaust gas exhausted from the diesel engine is brought into contact with the carrier of the NO x reduction catalyst, the temperature becomes high enough to activate the disordered oxygen defects, so that the NO x existing in the exhaust gas is is reduced with a catalyst, it can always maintain a high reducing action of NO X, to improve the NO X reduction rate,
As a result, the amount of NO X present in the exhaust gas can be reduced.
【００１１】[0011]
【発明の実施の形態】以下、図面を参照して、この発明
によるＮＯX 還元触媒の担持体の実施例を説明する。図
１はこの発明によるＮＯX 還元触媒の担持体の製造工程
の一実施例を示す説明図である。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a carrier for a NO x reduction catalyst according to the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing one embodiment of a manufacturing process of a carrier of a NO x reduction catalyst according to the present invention.
【００１２】このＮＯX 還元触媒の担持体は、例えば、
ディーゼルエンジンから排気される排気ガスのＮＯX を
低減して浄化する排気ガス浄化装置に適用されるもので
ある。一般に、ディーゼルエンジンは、シリンダブロッ
クに固定されたシリンダヘッド、シリンダヘッドに形成
した吸気ポート、排気ポート、シリンダブロックに設け
たシリンダライナ、シリンダライナに形成されるシリン
ダボア内とを往復動するピストンを有している。また、
排気ポートは排気管に連通され、該排気管に排気ガス浄
化装置が設けられている。このＮＯX 還元触媒の担持体
は、上記のような排気ガス浄化装置に組み込まれて使用
でき、ディーゼルエンジンから排出される排気ガス中の
ＮＯX を還元して低減し、Ｎ2 に転化させるのに使用さ
れる。The carrier for the NO x reduction catalyst is, for example,
The present invention is applied to an exhaust gas purification device that reduces and purifies NO x in exhaust gas discharged from a diesel engine. Generally, a diesel engine has a cylinder head fixed to a cylinder block, an intake port and an exhaust port formed in the cylinder head, a cylinder liner provided in the cylinder block, and a piston that reciprocates in a cylinder bore formed in the cylinder liner. are doing. Also,
The exhaust port communicates with the exhaust pipe, and the exhaust pipe is provided with an exhaust gas purification device. The carrier for the NO x reduction catalyst can be used by being incorporated in the exhaust gas purifying device as described above, and reduces and reduces NO x in the exhaust gas discharged from the diesel engine to convert it into N 2. Used for.
【００１３】この発明によるＮＯX 還元触媒の担持体で
は、基本構造体はハニカムセラミックス、フォーム状金
属やセラミックス及びフェルト状セラミックス繊維体か
ら選択される材料によって作製されている。上記基本構
造体が有する空孔中に、所定温度で酸素欠陥の秩序−無
秩序転移を示すブラウンミラライト型構造を有するＮＯ
X 還元触媒が担持されている。ここで、ブラウンミララ
イト型構造は、一般式がＡ2 Ｂ2 Ｏ5 で表されるもので
あり、Ａは２価の金属であり、Ｂは３価の金属である。In the NO X reduction catalyst carrier according to the present invention, the basic structure is made of a material selected from honeycomb ceramics, foam metal or ceramics, and felt ceramics fibrous body. NO having a Brown-Millalite type structure showing an order-disorder transition of oxygen defects at a predetermined temperature in the pores of the basic structure
X reduction catalyst is supported. Here, the brown-milarite type structure has a general formula represented by A 2 B 2 O 5 , where A is a divalent metal and B is a trivalent metal.
【００１４】この実施例では、所定温度において酸素欠
陥の秩序−無秩序転移を示すブラウンミラライト型構造
を持つＮＯX 還元触媒は、バリウム、イットリウム及び
酸素から成り、例えば、Ｂａ3 Ｙ4 Ｏ9 を使用すること
ができる。この実施例では、ブラウンミラライト型構造
を持つ化合物は、この他にＢａＬａ2 Ｏ4 を使用するこ
ともできる。In this example, the NO x reduction catalyst having a Brown-Millalite type structure showing an order-disorder transition of oxygen defects at a predetermined temperature is composed of barium, yttrium and oxygen. For example, Ba 3 Y 4 O 9 is used. Can be used. In this example, BaLa 2 O 4 may be used as the compound having a brown-milarite structure.
【００１５】次に、図１を参照して、このＮＯX 還元触
媒の担持体の製造方法の一実施例を説明する。このＮＯ
X 還元触媒の担持体の製造方法において、ハニカムセラ
ミックス、フォーム状金属やセラミックス及びフェルト
状セラミックス繊維体から選択される材料から空孔を持
つ基本構造体をを作製する。この実施例では、基本構造
体として、コーディエライト多孔質ハニカムセラミック
ス（以下、多孔体ともいう）を使用する。Next, with reference to FIG. 1, an embodiment of the method for producing the carrier of the NO x reduction catalyst will be described. This NO
In a method of manufacturing a support for an X reduction catalyst, a basic structure having pores is prepared from a material selected from honeycomb ceramics, foam metal or ceramics, and felt ceramics fibrous body. In this embodiment, cordierite porous honeycomb ceramics (hereinafter, also referred to as porous body) is used as the basic structure.
【００１６】図１に示すように、酢酸バリウムＢａ（Ｃ
Ｈ3 ＣＯＯ）2 を０．１４ｍｏｌと、硝酸イットリウム
Ｙ（ＮＯ3 ）3 を０．１６ｍｏｌとを含む５００ｃｃの
水溶液を作製した（ステップ１）。この水溶液を混合し
（ステップ２）、クエン酸Ｃ6 Ｈ8 Ｏ7 を０．３ｍｏｌ
添加し（ステップ３）、これを混合した（ステップ
４）。次いで、この混合溶液にカルボメチルセルロース
（ＣＭＣ）の３ｗｔ％水溶液を１００ｃｃ添加し、粘稠
な溶液を作製した（ステップ５）。ＣＭＣ溶液を添加し
た混合溶液中に、上記コーディエライト多孔質ハニカム
セラミックスを浸漬し、多孔質ハニカムセラミックスの
空孔中に上記混合溶液を含浸させた（ステップ６）。次
いで、上記混合溶液を含浸した多孔質ハニカムセラミッ
クスを２５０℃で加熱し、水分を蒸発させて乾燥させた
（ステップ７）。次に、乾燥したハニカムセラミックス
多孔体を９５０〜１１００℃で２時間焼成し、ハニカム
セラミックス多孔体の空孔中に含浸している混合物をブ
ラウンミラライト型構造を持つＢａ3 Ｙ4 Ｏ9 に転化
し、ハニカムセラミックス多孔体の空孔部に上記Ｂａ3
Ｙ4 Ｏ9 を担持させ、それによって、ブラウンミラライ
ト型構造を有するＮＯX 還元触媒を担持したハニカムセ
ラミックス多孔体（以下、本発明品という）を作製した
（ステップ８）。As shown in FIG. 1, barium acetate Ba (C
A 500 cc aqueous solution containing 0.14 mol of H 3 COO) 2 and 0.16 mol of yttrium nitrate Y (NO 3 ) 3 was prepared (step 1). This aqueous solution is mixed (step 2) and 0.3 mol of citric acid C 6 H 8 O 7 is added.
Add (step 3) and mix (step 4). Next, 100 cc of a 3 wt% aqueous solution of carbomethylcellulose (CMC) was added to this mixed solution to prepare a viscous solution (step 5). The cordierite porous honeycomb ceramics was immersed in the mixed solution containing the CMC solution to impregnate the pores of the porous honeycomb ceramics with the mixed solution (step 6). Next, the porous honeycomb ceramics impregnated with the above mixed solution was heated at 250 ° C. to evaporate the water content and dry it (step 7). Next, the dried honeycomb ceramics porous body is fired at 950 to 1100 ° C. for 2 hours, and the mixture impregnated in the pores of the honeycomb ceramics porous body is converted into Ba 3 Y 4 O 9 having a brown millerite structure. Then, the above-mentioned Ba 3 is added to the pores of the honeycomb ceramic porous body.
A honeycomb ceramic porous body (hereinafter referred to as a product of the present invention) carrying Y 4 O 9 and thereby carrying an NO X reduction catalyst having a brown millerite type structure was produced (step 8).
【００１７】本発明品と、従来のＮＯX 還元触媒を担持
させたコーディエライトハニカムセラミックス多孔体を
比較品として作製した。比較品の作製は、炭酸バリウム
を０．１４ｍｏｌと酸化イットリウムを０．１６ｍｏｌ
との水溶液を混合して混合溶液を作製した。この混合溶
液中に上記コーディエライトハニカムセラミックス多孔
体を浸漬し、コーディエライト多孔体の空孔中に上記混
合溶液を含浸させた。次いで、乾式法によって上記混合
溶液を含浸したハニカム構造のコーディエライト多孔体
を１３００℃で１時間焼成し、ＮＯX 還元触媒を担持し
たハニカム構造のコーディエライト多孔体を作製した。The product of the present invention and a conventional cordierite honeycomb ceramics porous body carrying a NO x reduction catalyst were prepared as comparative products. The comparative product was prepared by using 0.14 mol of barium carbonate and 0.16 mol of yttrium oxide.
The aqueous solutions of and were mixed to prepare a mixed solution. The above cordierite honeycomb ceramics porous body was immersed in this mixed solution to impregnate the pores of the cordierite porous body with the above mixed solution. Next, the honeycomb-structured cordierite porous body impregnated with the above-mentioned mixed solution was baked at 1300 ° C. for 1 hour by a dry method to prepare a honeycomb-structured cordierite porous body carrying a NO x reduction catalyst.
【００１８】そこで、本発明品と比較品との粉末の比表
面積とＮＯX の還元率を測定した。その結果を、表１及
び図２に示す。図２はＮＯX 還元触媒の粉末の比表面積
に対するＮＯX 還元率の関係を示すグラフである。この
測定条件として、測定温度は４００℃であり、ガス濃度
はＮＯX が８００ｐｐｍ／Ｎ2 であり、空間速度ＳＶは
５×１０4 ／ｈであった。Therefore, the specific surface area and the NO x reduction rate of the powder of the present invention product and the comparative product were measured. The results are shown in Table 1 and FIG. FIG. 2 is a graph showing the relationship between the NO x reduction rate and the specific surface area of the powder of the NO x reduction catalyst. As the measurement conditions, the measurement temperature was 400 ° C., the gas concentration was NO x 800 ppm / N 2 , and the space velocity SV was 5 × 10 4 / h.
【表１】 [Table 1]
【００１９】表１及び図２から分かるように、本発明品
の比表面積は、焼成温度によって異なるが、高温１１０
０℃で焼成した試料Ｎｏ．１は１．５ｍ2 ／ｇであり、
中間温度１０５０℃で焼成した試料Ｎｏ．２は５ｍ2 ／
ｇであり、低温９５０℃で焼成した試料Ｎｏ．３は１０
ｍ2 ／ｇであった。これ対して、比較品は、焼成温度が
１３００℃であるが、その比表面積は１．２ｍ2 ／ｇで
あった。また、本発明品のＮＯX 還元率は、それぞれ３
２％、３７％及び４０％であるのに対して、比較品のＮ
ＯX 還元率は２５％であった。As can be seen from Table 1 and FIG. 2, the specific surface area of the product of the present invention varies depending on the firing temperature.
Sample No. fired at 0 ° C. 1 is 1.5 m 2 / g,
Sample No. fired at an intermediate temperature of 1050 ° C. 2 is 5m 2 /
g, and sample No. fired at a low temperature of 950 ° C. 3 is 10
m 2 / g. On the other hand, the comparative product had a specific surface area of 1.2 m 2 / g although the firing temperature was 1300 ° C. The NO x reduction rate of the product of the present invention is 3 each.
2%, 37% and 40%, while the N of the comparative product
O X reduction rate was 25%.
【００２０】上記実施例では、本発明品の作製工程にお
いて、混合溶液中の酢酸根や硝酸根を加熱分解によって
除去したが、アンモニア水溶液や、他のアンモニウム基
を有するアルカリ液で反応させて除去しても同じ効果を
得ることができる。また、混合溶液の粘度を上げるため
に、カルボメチルセルロース（ＣＭＣ）を用いたが、そ
の他、例えば、ポリビニールアルコール等の高分子系増
粘材、或いは、加熱により硬化するフェノール系樹脂等
を用いることができる。In the above-mentioned Examples, the acetate radicals and nitrate radicals in the mixed solution were removed by thermal decomposition in the production process of the product of the present invention, but they are removed by reacting with an aqueous ammonia solution or another alkaline liquid having an ammonium group. However, the same effect can be obtained. In addition, although carbomethylcellulose (CMC) was used to increase the viscosity of the mixed solution, other than that, for example, a polymeric thickener such as polyvinyl alcohol or a phenolic resin that is hardened by heating is used. You can
【００２１】本発明品によるＮＯX 還元率の増大は、均
一混合溶液から比表面積の大きい粉末を合成したことに
よるものであるが、比表面積の増大は、低温焼成を可能
にしたことによるものである。この低温焼成は、バリウ
ム化合物とイットリウム化合物が溶液中で錯体となり、
バリウムとイットリウムの混合が均一になり、しかも粘
稠な高分子で半固定化されたまま、粉末にされたことに
よる効果と考えられる。即ち、ＮＯX 還元触媒の担持体
の比表面積は、焼成温度により制御されるものである。The increase in the NO x reduction rate by the product of the present invention is due to the synthesis of powder having a large specific surface area from the homogeneous mixed solution, but the increase in the specific surface area is due to the fact that low temperature calcination is possible. is there. In this low temperature firing, the barium compound and the yttrium compound become a complex in the solution,
It is considered that this is because the mixture of barium and yttrium became uniform, and the powder was made semi-immobilized with the viscous polymer while being made into powder. That is, the specific surface area of the carrier of the NO x reduction catalyst is controlled by the firing temperature.
【００２２】また、乾式の比較品と本発明品とによる粉
末のＸ線回折分析の結果から次のことが判った。即ち、
乾式の比較品では、炭酸バリウムのピークがあり、完全
にブラウンミラライト型構造になっていないのに対し、
本発明品は完全にブラウンミラライト型構造のピークに
なっていた。The results of X-ray diffraction analysis of the powders of the dry comparison product and the product of the present invention revealed the following. That is,
The dry comparison product has a peak of barium carbonate and does not have a completely brown-milarite type structure.
The product of the present invention had a peak of brown-milarite type structure completely.
【００２３】この発明による上記実施例では、基本構造
体としてコーディエライト多孔質ハニカムセラミックス
にＮＯX 還元触媒を担持させたが、フォーム状金属やセ
ラミックス及びフェルト状セラミックス繊維体から選択
される材料で基本構造体を構成し、それにＮＯX 還元触
媒を担持させることもできる。In the above-mentioned embodiment according to the present invention, the NO x reduction catalyst was supported on the cordierite porous honeycomb ceramics as the basic structure, but it is possible to use a material selected from foam metal or ceramics and felt ceramics fibrous body. It is also possible to form a basic structure and carry a NO x reduction catalyst thereon.
【００２４】[0024]
【発明の効果】この発明によるＮＯX 還元触媒の担持体
は、上記のように、コーディエライト多孔質ハニカムセ
ラミックスを主体とする基本構造体における空孔中に、
ブラウンミラライト型構造を有するＮＯX 還元触媒を担
持させたので、担持体自体の比表面積を大幅に大きくす
ることできる。しかも、このＮＯX 還元触媒の担持体
は、ＮＯX 還元触媒が完全なブラウンミラライト型構造
を有するので、粉末の比表面積が従来品のものに比較し
て大きく、また、ＮＯX の還元率が従来品のものに比較
して大きくなり、排気ガス中に含まれるＮＯX を効率的
に還元し、ＮＯX を還元作用で分解してＮ2 とＯ2 に変
化させ、排気ガス中のＮＯX を低減することができる。As described above, the carrier of the NO x reduction catalyst according to the present invention has, in the pores of the basic structure mainly composed of cordierite porous honeycomb ceramics,
Since the NO x reduction catalyst having the brown-milarite type structure was supported, the specific surface area of the carrier itself can be significantly increased. Moreover, the support of the NO X reduction catalyst because NO X reduction catalyst has a full brownmillerite type structure, large specific surface area of the powder as compared with the conventional products, also reduction rate of the NO X Is larger than that of the conventional product, NO x contained in the exhaust gas is efficiently reduced, and NO x is decomposed by the reducing action to be converted into N 2 and O 2 , and NO in the exhaust gas is reduced. X can be reduced.
【図１】この発明によるＮＯX 還元触媒の担持体を作製
する製造方法の一実施例を示すブロック図である。FIG. 1 is a block diagram showing an embodiment of a production method for producing a carrier for a NO x reduction catalyst according to the present invention.
【図２】ＮＯX 還元触媒の粉末の比表面積に対するＮＯ
X 還元率の関係を示すグラフである。FIG. 2 NO with respect to specific surface area of NO X reduction catalyst powder
It is a graph which shows the relationship of X reduction rate.
Claims (5)
やセラミックス及びフェルト状セラミックス繊維体から
選択される材料によって作製された基本構造体の空孔中
に、一般式Ａ2 Ｂ2 Ｏ5 を持つブラウンミラライト型構
造を有するＮＯX 還元触媒が担持され、Ａの位置にバリ
ウムを且つＢの位置にイットリウムを有し、Ｂａ3 Ｙ4
Ｏ9 となる基本構造に比べてＢａＯ分の欠損部分を有す
ることを特徴とするＮＯX 還元触媒の担持体。1. A brown mirrorlite having the general formula A 2 B 2 O 5 in the pores of a basic structure made of a material selected from honeycomb ceramics, foam metal or ceramics and felt ceramics fibrous body. A NO x reduction catalyst having a type structure is supported, barium is present at position A and yttrium is present at position B, and Ba 3 Y 4
A carrier for a NO x reduction catalyst, characterized in that it has a deficient portion in the amount of BaO as compared with the basic structure of O 9 .
記ＮＯX 還元触媒は、そのＹ／Ｂａの比が１．１〜１．
４の範囲にあることを特徴とする請求項１に記載のＮＯ
X 還元触媒の担持体。2. The NO x reduction catalyst having the brown-milarite type structure has a Y / Ba ratio of 1.1 to 1.
4. The NO according to claim 1, wherein the NO is in the range of 4.
Support for X reduction catalyst.
記ＮＯX 還元触媒の粉末の比表面積は、１．５ｍ2 ／ｇ
以上であることを特徴とする請求項１に記載のＮＯX 還
元触媒の担持体。3. The specific surface area of the powder of the NO x reduction catalyst having the brown-milarite type structure is 1.5 m 2 / g.
Carrier of the NO X reduction catalyst according to claim 1, characterized in that at least.
記Ｂａ3 Ｙ4 Ｏ9 の構造は、そのバリウムの位置の１分
子以下の量をニッケル、コバルト、鉄の少なくとも１種
に変えたものであることを特徴とする請求項１に記載の
ＮＯX 還元触媒の担持体。4. The structure of Ba 3 Y 4 O 9 having the brown-milarite structure is such that the amount of one molecule or less at the barium position is changed to at least one of nickel, cobalt and iron. The carrier for the NO x reduction catalyst according to claim 1, which is characterized in that.
記Ｂａ3 Ｙ4 Ｏ9 の構造は、そのイットリウムの位置の
１分子以下の量をランタン、エルビュウム、ディスプロ
シウムの少なくとも１種で一部を置換したものであるこ
とを特徴とする請求項１に記載のＮＯX 還元触媒の担持
体。5. The structure of the Ba 3 Y 4 O 9 having the brown-milarite type structure is such that the amount of one molecule or less at the position of yttrium is at least one of lanthanum, erbium and dysprosium. The NO X reduction catalyst carrier according to claim 1, which is substituted.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8093059A JPH09253506A (en) | 1996-03-25 | 1996-03-25 | Carrier for nox reducing catalyst |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8093059A JPH09253506A (en) | 1996-03-25 | 1996-03-25 | Carrier for nox reducing catalyst |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09253506A true JPH09253506A (en) | 1997-09-30 |
Family
ID=14071949
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8093059A Pending JPH09253506A (en) | 1996-03-25 | 1996-03-25 | Carrier for nox reducing catalyst |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09253506A (en) |
-
1996
- 1996-03-25 JP JP8093059A patent/JPH09253506A/en active Pending
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