JP2001000863A - Waste gas purifying catalyst and waste gas purifying method using the catalyst - Google Patents
Waste gas purifying catalyst and waste gas purifying method using the catalystInfo
- Publication number
- JP2001000863A JP2001000863A JP2000006033A JP2000006033A JP2001000863A JP 2001000863 A JP2001000863 A JP 2001000863A JP 2000006033 A JP2000006033 A JP 2000006033A JP 2000006033 A JP2000006033 A JP 2000006033A JP 2001000863 A JP2001000863 A JP 2001000863A
- Authority
- JP
- Japan
- Prior art keywords
- catalyst
- exhaust gas
- carrier
- gas purifying
- storage material
- 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.)
- Granted
Links
- 239000003054 catalyst Substances 0.000 title claims abstract description 315
- 238000000034 method Methods 0.000 title claims description 23
- 239000002912 waste gas Substances 0.000 title abstract 5
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 30
- 239000011593 sulfur Substances 0.000 claims abstract description 30
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 30
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 23
- 239000000463 material Substances 0.000 claims abstract description 18
- 239000011232 storage material Substances 0.000 claims description 74
- 238000003860 storage Methods 0.000 claims description 48
- 239000000446 fuel Substances 0.000 claims description 19
- 238000000746 purification Methods 0.000 claims description 17
- 229910052783 alkali metal Inorganic materials 0.000 claims description 16
- 150000001340 alkali metals Chemical class 0.000 claims description 16
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 16
- 150000001342 alkaline earth metals Chemical class 0.000 claims description 16
- 229910000510 noble metal Inorganic materials 0.000 claims description 14
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 11
- 239000002131 composite material Substances 0.000 claims description 5
- 229910052700 potassium Inorganic materials 0.000 claims description 5
- 229910020068 MgAl Inorganic materials 0.000 claims description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 2
- 231100000572 poisoning Toxicity 0.000 abstract description 12
- 230000000607 poisoning effect Effects 0.000 abstract description 12
- 239000007789 gas Substances 0.000 description 153
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 23
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 21
- 239000000843 powder Substances 0.000 description 17
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 16
- 230000003197 catalytic effect Effects 0.000 description 13
- 238000001179 sorption measurement Methods 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 9
- 238000012360 testing method Methods 0.000 description 9
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 8
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 8
- 229910002091 carbon monoxide Inorganic materials 0.000 description 8
- 229930195733 hydrocarbon Natural products 0.000 description 8
- 150000002430 hydrocarbons Chemical class 0.000 description 8
- 239000007864 aqueous solution Substances 0.000 description 7
- 239000011812 mixed powder Substances 0.000 description 7
- 239000008188 pellet Substances 0.000 description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Chemical compound [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 description 6
- 239000002243 precursor Substances 0.000 description 6
- 239000000758 substrate Substances 0.000 description 6
- 230000007423 decrease Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 229910052744 lithium Inorganic materials 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 229910052697 platinum Inorganic materials 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- 238000011068 loading method Methods 0.000 description 4
- SCVFZCLFOSHCOH-UHFFFAOYSA-M potassium acetate Chemical compound [K+].CC([O-])=O SCVFZCLFOSHCOH-UHFFFAOYSA-M 0.000 description 4
- 239000010948 rhodium Substances 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 3
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 3
- 239000000919 ceramic Substances 0.000 description 3
- 238000003795 desorption Methods 0.000 description 3
- 229910017604 nitric acid Inorganic materials 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 2
- 229910000013 Ammonium bicarbonate Inorganic materials 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- FHKPLLOSJHHKNU-INIZCTEOSA-N [(3S)-3-[8-(1-ethyl-5-methylpyrazol-4-yl)-9-methylpurin-6-yl]oxypyrrolidin-1-yl]-(oxan-4-yl)methanone Chemical compound C(C)N1N=CC(=C1C)C=1N(C2=NC=NC(=C2N=1)O[C@@H]1CN(CC1)C(=O)C1CCOCC1)C FHKPLLOSJHHKNU-INIZCTEOSA-N 0.000 description 2
- 235000012538 ammonium bicarbonate Nutrition 0.000 description 2
- 239000001099 ammonium carbonate Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910052788 barium Inorganic materials 0.000 description 2
- ITHZDDVSAWDQPZ-UHFFFAOYSA-L barium acetate Chemical compound [Ba+2].CC([O-])=O.CC([O-])=O ITHZDDVSAWDQPZ-UHFFFAOYSA-L 0.000 description 2
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 2
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 229910052746 lanthanum Inorganic materials 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 235000011056 potassium acetate Nutrition 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 241000894007 species Species 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- YLZOPXRUQYQQID-UHFFFAOYSA-N 3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)-1-[4-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]piperazin-1-yl]propan-1-one Chemical compound N1N=NC=2CN(CCC=21)CCC(=O)N1CCN(CC1)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F YLZOPXRUQYQQID-UHFFFAOYSA-N 0.000 description 1
- DEXFNLNNUZKHNO-UHFFFAOYSA-N 6-[3-[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]piperidin-1-yl]-3-oxopropyl]-3H-1,3-benzoxazol-2-one Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C1CCN(CC1)C(CCC1=CC2=C(NC(O2)=O)C=C1)=O DEXFNLNNUZKHNO-UHFFFAOYSA-N 0.000 description 1
- 102100033040 Carbonic anhydrase 12 Human genes 0.000 description 1
- 102100033041 Carbonic anhydrase 13 Human genes 0.000 description 1
- 102100033007 Carbonic anhydrase 14 Human genes 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 229910052692 Dysprosium Inorganic materials 0.000 description 1
- 101100321669 Fagopyrum esculentum FA02 gene Proteins 0.000 description 1
- 101000867855 Homo sapiens Carbonic anhydrase 12 Proteins 0.000 description 1
- 101000867860 Homo sapiens Carbonic anhydrase 13 Proteins 0.000 description 1
- 101000867862 Homo sapiens Carbonic anhydrase 14 Proteins 0.000 description 1
- 101100293260 Homo sapiens NAA15 gene Proteins 0.000 description 1
- 101000741917 Homo sapiens Serine/threonine-protein phosphatase 1 regulatory subunit 10 Proteins 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 102100026781 N-alpha-acetyltransferase 15, NatA auxiliary subunit Human genes 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- 101100121112 Oryza sativa subsp. indica 20ox2 gene Proteins 0.000 description 1
- 101100121113 Oryza sativa subsp. japonica GA20OX2 gene Proteins 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 102100038743 Serine/threonine-protein phosphatase 1 regulatory subunit 10 Human genes 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910052790 beryllium Inorganic materials 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052792 caesium Inorganic materials 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 229910052878 cordierite Inorganic materials 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 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 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- KDLHZDBZIXYQEI-UHFFFAOYSA-N palladium Substances [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- VXNYVYJABGOSBX-UHFFFAOYSA-N rhodium(3+);trinitrate Chemical compound [Rh+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VXNYVYJABGOSBX-UHFFFAOYSA-N 0.000 description 1
- 229910052701 rubidium Inorganic materials 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052706 scandium Inorganic materials 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 238000002336 sorption--desorption measurement Methods 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical class [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- 210000003371 toe Anatomy 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は排ガス中に含まれる
一酸化炭素（ＣＯ）や炭化水素（ＨＣ）を酸化するのに
必要な量より過剰な酸素が含まれている排ガス中の、Ｎ
Ｏxを効率よく浄化できる排ガス浄化用触媒およびその
触媒を用いた排ガス浄化方法に関する。[0001] The present invention relates to a method for reducing the amount of N contained in an exhaust gas containing oxygen in excess of that required for oxidizing carbon monoxide (CO) and hydrocarbons (HC) contained in the exhaust gas.
The present invention relates to an exhaust gas purifying catalyst capable of efficiently purifying O x and an exhaust gas purifying method using the catalyst.
【０００２】[0002]
【従来の技術】リーンバーンエンジンにおいて、常時は
酸素過剰の燃料リーン条件で燃焼させ、間欠的に燃料ス
トイキ〜リッチ条件とすることにより排ガスを還元雰囲
気としてＮＯxを還元浄化するシステムが開発され、実
用化されている。そしてこのシステムに最適な触媒とし
て、リーン雰囲気でＮＯxを吸蔵し、ストイキ〜リッチ
雰囲気で吸蔵されたＮＯxを放出するＮＯx吸蔵材を用い
たＮＯx吸蔵還元型の排ガス浄化用触媒が開発されてい
る。BACKGROUND ART In a lean-burn engine, normally is burned with oxygen excess fuel lean condition, the system reduces and purifies NO x exhaust gas as a reducing atmosphere is developed by the intermittent fuel stoichiometric-rich condition, Has been put to practical use. And as the best catalysts for this system, occludes NO x in lean atmosphere, stoichiometric ~ the NO x storage-reduction type exhaust purifying catalyst is developing with the NO x storage material that releases occluded NO x in a rich atmosphere Have been.
【０００３】例えば特開平５−３１７６５２号公報に
は、Ｂａなどのアルカリ土類金属とＰｔをアルミナなど
の多孔質酸化物担体に担持した排ガス浄化用触媒が提案
されている。また特開平６−３１１３９号公報には、Ｋ
などのアルカリ金属とＰｔをアルミナなどの多孔質酸化
物担体に担持した排ガス浄化用触媒が提案されている。
さらに特開平５−１６８８６０号公報には、Ｌａなどの
希土類元素とＰｔをアルミナなどの多孔質酸化物担体に
担持した排ガス浄化用触媒が提案されている。For example, JP-A-5-317652 proposes an exhaust gas purifying catalyst in which an alkaline earth metal such as Ba and Pt are supported on a porous oxide carrier such as alumina. Japanese Patent Application Laid-Open No. 6-31139 discloses K
There has been proposed an exhaust gas purifying catalyst in which an alkali metal such as Pt is supported on a porous oxide carrier such as alumina.
Further, Japanese Patent Application Laid-Open No. 5-168860 proposes an exhaust gas purifying catalyst in which a rare earth element such as La and Pt are supported on a porous oxide carrier such as alumina.
【０００４】このＮＯx吸蔵還元型触媒を用いれば、空
燃比をリーン側からパルス状にストイキ〜リッチ側とな
るように制御することにより、排ガスもリーン雰囲気か
らパルス状にストイキ〜リッチ雰囲気となる。したがっ
て、リーン側ではＮＯxがＮＯx吸蔵材に吸蔵され、それ
がストイキ又はリッチ側で放出されてＨＣやＣＯなどの
還元性成分と反応して浄化されるため、リーンバーンエ
ンジンからの排ガスであってもＮＯxを効率良く浄化す
ることができる。また排ガス中のＨＣ及びＣＯは、貴金
属により酸化されるとともにＮＯxの還元にも消費され
るので、ＨＣ及びＣＯも効率よく浄化される。If this NO x storage reduction catalyst is used, the exhaust gas changes from a lean atmosphere to a stoichiometric to rich atmosphere from a lean atmosphere by controlling the air-fuel ratio from a lean side to a stoichiometric to rich side. . Thus, NO x is occluded in the NO x storage material in the lean side, because it is purified by reacting with reducing components, such as being released in the stoichiometric or rich side HC and CO, in exhaust gases from lean-burn engines can efficiently purify NO x even. Further, HC and CO in the exhaust gas are oxidized by the noble metal and consumed for reduction of NO x , so that HC and CO are also efficiently purified.
【０００５】ところが排ガス中には、燃料中に含まれる
硫黄（Ｓ）が燃焼して生成したＳＯ xが含まれ、それが
リーン雰囲気の排ガス中で貴金属により酸化されて例え
ばＳＯ3となる。そしてそれがやはり排ガス中に含まれ
る水蒸気により容易に硫酸となり、これらがＮＯx吸蔵
材と反応して亜硫酸塩や硫酸塩が生成し、これによりＮ
Ｏx吸蔵材が被毒劣化することが明らかとなった。つま
り、このようにＮＯx吸蔵材が亜硫酸塩や硫酸塩となっ
て被毒劣化すると、もはやＮＯxを吸蔵することができ
なくなり、耐久後のＮＯx浄化性能が低下するという問
題である。However, exhaust gas contains fuel.
SO generated by combustion of sulfur (S) xIs included
Oxidized by precious metals in the exhaust gas of lean atmosphere
If SOThreeBecomes And that is also included in the exhaust gas
Sulfuric acid is easily converted to water vapor,xOcclusion
Reacts with wood to form sulfites and sulfates,
OxIt became clear that the occlusion material was poisoned and deteriorated. Toes
And thus NOxThe storage material becomes sulfite or sulfate
NO after poisoningxCan occlude
NO, NO after endurancexThe problem that purification performance decreases
It is a title.
【０００６】[0006]
【発明が解決しようとする課題】近年の大気汚染の現状
と排ガス規制の強化に鑑みると、従来のＮＯx吸蔵還元
型の排ガス浄化用触媒では、耐久後のＮＯx浄化性能が
充分ではなく、そのため初期から耐久後まで高いＮＯx
浄化性能を示す排ガス浄化用触媒の早期開発が望まれて
いる。In view of the current state of air pollution and the tightening of exhaust gas regulations in recent years, the conventional NO x storage-reduction type exhaust gas purifying catalyst does not have sufficient NO x purification performance after durability. Therefore, high NO x from the beginning to the end of durability
There is a demand for early development of an exhaust gas purification catalyst exhibiting purification performance.
【０００７】本発明はこのような事情に鑑みてなされた
ものであり、ＮＯx吸蔵材の硫黄被毒をさらに抑制し
て、ＮＯx吸蔵還元型の排ガス浄化用触媒の耐久性を一
層向上させることを目的とする。The present invention has been made in view of such circumstances, and further suppresses sulfur poisoning of the NO x storage material, and further improves the durability of the NO x storage reduction type exhaust gas purifying catalyst. The purpose is to:
【０００８】[0008]
【課題を解決するための手段】本発明の排ガス浄化用触
媒は、多孔質酸化物からなる担体と、該担体に担持され
た貴金属と、該担体に担持されたアルカリ金属、アルカ
リ土類金属および希土類元素から選ばれる少なくとも１
種の第１ＮＯx吸蔵材とを含んでなり、排ガスの上流側
に位置する第１触媒と、多孔質酸化物からなる担体と、
該担体に担持された貴金属と、該担体に担持されたアル
カリ金属、アルカリ土類金属および希土類元素から選ば
れる少なくとも１種の第２ＮＯx吸蔵材とを含んでな
り、排ガスの下流側に位置する第２触媒と、からなるＮ
Ｏx吸蔵還元型の排ガス浄化用触媒であって、前記第１
ＮＯx吸蔵材は、前記第２ＮＯx吸蔵材よりも、硫黄吸着
しやすくかつ硫黄離脱しにくい特性を持つことを特徴と
する。The exhaust gas purifying catalyst of the present invention comprises a carrier comprising a porous oxide, a noble metal supported on the carrier, an alkali metal, an alkaline earth metal supported on the carrier, At least one selected from rare earth elements
A first catalyst comprising a first NO x storage material of a kind and located on the upstream side of the exhaust gas, a carrier made of a porous oxide,
It comprises a noble metal supported on the carrier, and at least one kind of second NO x storage material selected from alkali metals, alkaline earth metals, and rare earth elements supported on the carrier, and is located downstream of the exhaust gas. A second catalyst comprising N
A O x storage reduction catalyst for purifying an exhaust gas, said first
The NO x storage material than said first 2NO x occluding material, characterized by having a sulfur adsorption easily and sulfur leaving hardly characteristics.
【０００９】一般に、ＮＯx吸蔵還元型触媒において、
硫黄被毒は、排ガスの上流側に位置する部分に集中する
傾向があり、特にモノリス型触媒（例えば、ハニカム基
材に担体をコートし、ハニカム体として形成した触媒）
においてはその傾向が強い。アルカリ金属、アルカリ土
類金属、希土類元素をＮＯx吸蔵材として用いる場合に
は、このＮＯx吸蔵材へのＳＯxの吸着は不可避的なもの
であるが、吸着されたＳＯxは燃料ストイキ〜リッチ雰
囲気とすることによって離脱が可能である。ところが、
一旦離脱させた場合であっても、下流側で再びＮＯx吸
蔵材に吸着するといった現象をも生じ得る。Generally, in a NO x storage reduction catalyst,
Sulfur poisoning tends to concentrate on the portion located on the upstream side of the exhaust gas, and is particularly a monolith catalyst (for example, a catalyst in which a honeycomb substrate is coated with a carrier and formed as a honeycomb body).
In, this tendency is strong. Alkali metals, alkaline earth metals, in the case of using a rare earth element as the NO x storage material is adsorbed of the SO x to the the NO x storage material are those unavoidable, adsorbed SO x fuel stoichiometric ~ By making the atmosphere rich, separation is possible. However,
Even when once disengages, it may also occur a phenomenon adsorb again the NO x storage material on the downstream side.
【００１０】上記本発明のＮＯx吸蔵還元型触媒では、
上流側、下流側の部分に分け、２種類の硫黄吸着・離脱
特性（ＳＯxの吸着しやすさおよび離脱のしやすさ）の
異なるＮＯx吸蔵材をそれぞれに配している。つまり、
より硫黄吸着しやすくかつ硫黄離脱しにくい特性を持つ
ＮＯx吸蔵材を上流側に配することで、燃料リーン雰囲
気において優先的に上流側に存在する触媒の部分にＳＯ
xを吸着させ、間欠的に生じる燃料ストイキ〜リッチ雰
囲気において、吸着したＳＯxを離脱還元させるもので
ある。一方、下流側の触媒の部分では、硫黄吸着しにく
いＮＯx吸蔵材を配していることから、このストイキ〜
リッチ雰囲気において離脱還元されたＳＯxは、下流側
の触媒の部分には吸着せずに排気されることとなる。こ
のような作用により、本発明の排ガス浄化用触媒では、
硫黄被毒が抑制され耐久性が向上させられる。In the NO x storage reduction catalyst of the present invention,
There are two types of NO x storage materials having different sulfur adsorption / desorption characteristics (easy adsorption and desorption of SO x ), which are divided into an upstream portion and a downstream portion. That is,
By arranging the the NO x storage material with more sulfur adsorbed easily and sulfur leaving hardly characteristics upstream, SO to the portion of the catalyst present in preferentially upstream in the fuel lean atmosphere
x is adsorbed and the adsorbed SO x is desorbed and reduced in an intermittent fuel stoichiometric to rich atmosphere. On the other hand, in the portion of the downstream side of the catalyst, since it is arranged sulfur adsorption hardly the NO x storage material, the stoichiometric-
It leaving reduced SO x in a rich atmosphere, and thus is exhausted without adsorption to the portion of the downstream side of the catalyst. By such an action, in the exhaust gas purifying catalyst of the present invention,
Sulfur poisoning is suppressed and durability is improved.
【００１１】なお、ＳＯxとＮＯx吸蔵材との反応は、Ｎ
Ｏx吸蔵材に吸着したＳＯxが、排ガス中に含まれる水蒸
気により容易に亜硫酸、硫酸等となり、これらがＮＯx
吸蔵材と反応して亜硫酸塩、硫酸塩等が生成しするよう
に進行するものと考えられる。したがって、「吸着」と
いう語は、単に吸着するのみではなく、吸着後の上記反
応をも含むことを意味する。また、「離脱」とは、上記
反応が逆に進行することをも含むことを意味する。The reaction between SO x and the NO x storage material is based on N
The SO x adsorbed on the O x storage material easily becomes sulfurous acid, sulfuric acid, or the like due to water vapor contained in the exhaust gas, and these become NO x
It is considered that the reaction proceeds with the formation of a sulfite, a sulfate and the like by reacting with the occluding material. Thus, the term “adsorption” means not only adsorption but also the above reaction after adsorption. In addition, “withdrawal” means that the above-mentioned reaction proceeds in reverse.
【００１２】さらに、本発明の排ガス浄化方法は、上記
本発明の排ガス浄化用触媒を用い、この排ガス浄化用触
媒を、間欠的に燃料ストイキ〜リッチ雰囲気となるリー
ンバーンエンジンからの排ガスに接触させ、燃料リーン
雰囲気で該排ガス中に含まれるＮＯxを該第１ＮＯx吸蔵
材および該第２ＮＯx吸蔵材に吸蔵させ、燃料ストイキ
〜リッチ雰囲気で該第１ＮＯx吸蔵材および該第２ＮＯx
吸蔵材から放出されたＮＯxを還元させることを特徴と
する。Further, in the exhaust gas purifying method of the present invention, the exhaust gas purifying catalyst of the present invention is used, and the exhaust gas purifying catalyst is intermittently brought into contact with exhaust gas from a lean burn engine which is in a fuel stoichiometric to rich atmosphere. the NO x contained in the exhaust gas in the fuel-lean atmosphere is occluded into said 1NO x storage material and said 2NO x storage material, the fuel stoichiometry ~ said 1NO x storage material and said 2NO x rich atmosphere
It is characterized in that NO x released from the storage material is reduced.
【００１３】上記本発明の排ガス浄化用触媒を用い、間
欠的に燃料ストイキ〜リッチ雰囲気をつくりだすこと
で、本発明の排ガス浄化方法は、硫黄被毒による劣化を
抑制しつつ、リーンバーンエンジンの排ガスから効率的
にＮＯxを浄化させることができる。By using the exhaust gas purifying catalyst of the present invention to intermittently create a fuel stoichiometric to rich atmosphere, the exhaust gas purifying method of the present invention suppresses the deterioration due to sulfur poisoning and reduces the exhaust gas of a lean burn engine. efficiently thereby purify NO x from.
【００１４】[0014]
【発明の実施の形態】以下に、本発明の実施の形態につ
いて詳細に説明する。Embodiments of the present invention will be described below in detail.
【００１５】本発明の排ガス浄化用触媒は、排ガスの上
流側に位置する第１触媒と、排ガスの下流に位置する第
２触媒とからなる。この第１触媒と第２触媒とは、一体
に形成されたものであってもよく、また、それぞれ分離
して形成されたものであってもよい。つまり、モノリス
型の触媒の場合には、１つのモノリス（ハニカム体とし
て形成された触媒）の上流部分と下流部分のそれぞれに
異なるＮＯx吸蔵材を担持させて、１つの触媒コンバー
タに組み込む態様のものでもよく、また、異なるＮＯx
吸蔵材を担持させた２つのモノリスを用い、連結して若
しくは適当な間隔を隔てて１つの触媒コンバータに組み
込む態様のものであってもよい。さらにまた、第１触媒
と第２触媒とを別々の触媒コンバータに組み込んで、こ
の２つの触媒コンバータを排ガス流路中に直列に配置さ
せるものであってもよい。ペレット型の触媒の場合は、
第１触媒となる複数のペレットと第２触媒となる複数の
ペレットとをそれぞれ群体とし、両ペレット群を直列に
１つの触媒コンバータに組み込む態様のものでもよく、
また、それぞれのペレット群を別々の触媒コンバータに
組み込んで、この２つの触媒コンバータを排ガス流路中
に直列に配置させるものであってもよい。なお、第１触
媒または第２触媒のいずれか一方をモノリス型、他方を
ペレット型にすることも可能である。The exhaust gas purifying catalyst of the present invention comprises a first catalyst located upstream of the exhaust gas and a second catalyst located downstream of the exhaust gas. The first catalyst and the second catalyst may be formed integrally, or may be formed separately from each other. In other words, in the case of a monolith type catalyst, a different NO x storage material is supported on each of the upstream portion and the downstream portion of one monolith (catalyst formed as a honeycomb body) and incorporated into one catalytic converter. Or different NO x
An embodiment may be used in which two monoliths carrying an occluding material are connected to each other or connected at an appropriate interval to one catalytic converter. Furthermore, the first catalyst and the second catalyst may be incorporated in separate catalytic converters, and the two catalytic converters may be arranged in series in the exhaust gas passage. In the case of a pellet type catalyst,
A plurality of pellets serving as the first catalyst and a plurality of pellets serving as the second catalyst may be grouped, and both pellet groups may be incorporated in series in one catalytic converter.
Further, each of the pellet groups may be incorporated in a separate catalytic converter, and the two catalytic converters may be arranged in series in the exhaust gas passage. Note that one of the first catalyst and the second catalyst may be a monolith type, and the other may be a pellet type.
【００１６】第１触媒および第２触媒とも、多孔質酸化
物からなる担体と、該担体に担持された貴金属と、該担
体に担持されたアルカリ金属、アルカリ土類金属および
希土類元素から選ばれる少なくとも１種のＮＯx吸蔵材
とを含んで構成される。以下に、これらの構成要素につ
いて説明する。In both the first catalyst and the second catalyst, a support made of a porous oxide, a noble metal supported on the support, and at least one selected from an alkali metal, an alkaline earth metal, and a rare earth element supported on the support. And one kind of NO x storage material. Hereinafter, these components will be described.
【００１７】貴金属およびＮＯx吸蔵材を担持する担体
は、多孔質酸化物からなり、用いることのできる多孔質
酸化物としては、例えば、アルミナ（Ａｌ2Ｏ3）、ゼオ
ライト、シリカ（ＳｉＯ2）、ジルコニア（ＺｒＯ2）、
チタニア（ＴｉＯ2）等や、これらを複合させたＴｉＯ2
−Ａｌ2Ｏ3、ＳｉＯ2−Ａｌ2Ｏ3、ＺｒＯ2−Ａｌ2Ｏ 3等
を挙げることができる。また、浄化性能の向上を目的と
して、セリア（ＣｅＯ2）や、ジルコニアで安定させた
セリア（セリア−ジルコニア複合酸化物：ＣｅＯ2−Ｚ
ｒＯ2）を添加するものであってもよい。モノリス型の
触媒を形成させる場合は、これらの酸化物をスラリー状
にして、コージェライト等のセラミックス、耐熱合金等
からなるハニカム基材にコートさせて担体とすればよ
く、また、ペレット型の触媒の場合には、これらの酸化
物を所定の大きさの粒状に焼結させて担体とすればよ
い。Noble metals and NOxCarrier that supports occlusion material
Is a porous oxide that can be used
As the oxide, for example, alumina (AlTwoOThree), Zeo
Light, silica (SiOTwo), Zirconia (ZrO)Two),
Titania (TiOTwo) And the like and TiOTwo
-AlTwoOThree, SiOTwo-AlTwoOThree, ZrOTwo-AlTwoO Threeetc
Can be mentioned. Also, with the aim of improving purification performance
And ceria (CeOTwo) Or zirconia stabilized
Ceria (Ceria-zirconia composite oxide: CeOTwo-Z
rOTwo) May be added. Monolithic
When forming a catalyst, these oxides should be slurried.
Ceramics such as cordierite, heat-resistant alloys, etc.
Can be coated on a honeycomb substrate consisting of
In the case of a pellet type catalyst,
What is necessary is to sinter the product into granules of a predetermined size and use it as a carrier
No.
【００１８】担体に担持させる貴金属は、主に、ＣＯ、
ＨＣを酸化させるのと同時に、排ガス中のＮＯxの主成
分たるＮＯを酸化させてＮＯ2として、ＮＯx吸蔵材に吸
蔵させやすくする役割りを果たす。用いることのできる
貴金属としては、Ｐｔ、Ｒｈ、Ｐｄ、Ｉｒ、Ｒｕ等を挙
げることができる。触媒の特性に応じ、これらの内の１
種または２種以上を、選択的に担持させればよい。担持
の方法については特に限定するものでなく、用いる貴金
属に応じた既に公知の方法にて行えばよい。上記貴金属
の担持量は、例えばモノリス型の触媒を形成させるので
あれば、担体体積１リットル当たりに、Ｐｔ、Ｒｄの場
合は０．１〜２０ｇとするが好ましく、０．５〜１０ｇ
とするのがより好ましい。また、Ｒｈの場合は、０．０
１〜１０ｇとするのが好ましく、０．０５〜５ｇとする
のがより好ましい。The noble metals supported on the carrier are mainly CO,
At the same time as oxidizing HC, it plays a role of oxidizing NO, which is the main component of NO x in the exhaust gas, as NO 2, so as to be easily stored in the NO x storage material. Examples of the noble metal that can be used include Pt, Rh, Pd, Ir, and Ru. Depending on the characteristics of the catalyst, one of these
The species or two or more species may be selectively carried. The loading method is not particularly limited, and may be carried out by a known method according to the noble metal used. The amount of the noble metal carried is preferably, for example, 0.1 to 20 g for Pt and Rd per 1 liter of the carrier volume if a monolithic catalyst is to be formed, and 0.5 to 10 g for Pt and Rd.
More preferably, In the case of Rh, 0.0
The amount is preferably 1 to 10 g, and more preferably 0.05 to 5 g.
【００１９】担体に担持させるＮＯx吸蔵材は、燃料リ
ーン雰囲気下でＮＯxを吸蔵し、燃料ストイキ〜リッチ
雰囲気下でＮＯxを放出させる役割りを果たし、アルカ
リ金属、アルカリ土類金属および希土類元素から選ばれ
る少なくとも１種以上を用いることができる。アルカリ
金属としてはＬｉ、Ｎａ、Ｋ、Ｒｂ、Ｃｓが、アルカリ
土類金属としてはＢｅ、Ｍｇ、Ｃａ、Ｓｒ、Ｂａが、希
土類元素としてはＳｃ、Ｙ、Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、
Ｄｙ、Ｙｂ等がそれぞれ例示できる。[0019] the NO x storage material to be supported on the carrier, occludes NO x under fuel-lean atmosphere, plays a role of releasing the NO x under fuel stoichiometric-rich atmosphere, alkali metals, alkaline earth metals and rare earth At least one selected from elements can be used. Li, Na, K, Rb, Cs as alkali metals, Be, Mg, Ca, Sr, Ba as alkaline earth metals, and Sc, Y, La, Ce, Pr, Nd, as rare earth elements.
Dy, Yb, etc. can be exemplified.
【００２０】本発明の排ガス浄化用触媒においては、排
ガスの上流側に位置する第１触媒と、下流側に位置する
第２触媒とで、硫黄吸着・離脱特性の異なるＮＯx吸蔵
材を担持させる。つまり第１触媒には、ＳＯxが吸着し
やすくかつ離脱しにくい特性を持つ第１のＮＯx吸蔵材
を担持させ、第２触媒には、ＳＯxが吸着しにくくかつ
離脱しやすい特性を持つ第２のＮＯx吸蔵材を担持させ
る。なお、第１触媒または第２触媒のそれぞれに２種以
上のＮＯx吸蔵材を担持させることもできることから、
この「第１ＮＯx吸蔵材」および「第２ＮＯx吸蔵材」と
は、それぞれ第１触媒および第２触媒に担持されるＮＯ
x吸蔵材の総称であることを意味する。したがって、２
種以上のＮＯx吸蔵材を担持させた場合、第１ＮＯx吸蔵
材を構成する個々のＮＯx吸蔵材のすべてが、第２ＮＯx
吸蔵材を構成する個々のＮＯx吸蔵材より、ＳＯxが吸着
しやすくかつ離脱しにくい特性を持つ必要はなく、第１
ＮＯx吸蔵材および第２ＮＯx吸蔵材それぞれの総合特性
として、第１ＮＯx吸蔵材が第２ＮＯx吸蔵材よりもＳＯ
xが吸着しやすくかつ離脱しにくい特性を有していれば
よい。[0020] In the exhaust gas purifying catalyst of the present invention, in a first catalyst positioned upstream of the exhaust gas, and a second catalyst located downstream, is supported different the NO x storage material sulfur adsorption and extraction characteristics . In other words, the first catalyst carries a first NO x storage material having characteristics that SO x is easily adsorbed and hardly desorbed, and the second catalyst has characteristics that SO x is hardly adsorbed and easily desorbed. The second NO x storage material is supported. In addition, since two or more types of NO x storage materials can be supported on each of the first catalyst and the second catalyst,
The “first NO x storage material” and “second NO x storage material” refer to the NO carried on the first catalyst and the second catalyst, respectively.
x means a generic term for occlusion materials. Therefore, 2
Case of carrying seeds or NO x storage material, all individual NO x storage material constituting the first 1NO x storage material, the 2NO x
There is no need for SO x to have a characteristic of being easily adsorbed and hard to be desorbed from the individual NO x occluding materials constituting the occluding material.
As a general characteristic of each the NO x storage material and the 2NO x storage component is first 1NO x storage material than the 2NO x occluding material SO
It is only necessary that x has a property that it is easily adsorbed and hardly desorbed.
【００２１】ＮＯx吸蔵材は、アルカリ度が高くＮＯx吸
蔵能力に優れるという点を考慮すれば、アルカリ金属、
アルカリ土類金属の中から選択するのが望ましい。ＳＯ
xが吸着しやすくかつ離脱しにくい特性という点では、
アルカリ土類金属がアルカリ金属に比較して優れてい
る。このことを考慮すれば、第１ＮＯx吸蔵材にアルカ
リ土類金属を含ませ、かつ、第２ＮＯx吸蔵材にアルカ
リ金属を含ませることが望ましい。さらに、１モル当た
りのＮＯx、ＳＯx吸着量が多いという理由から、第１Ｎ
Ｏx吸蔵材に含ませるアルカリ土類金属としては、Ｂａ
を用いるのが望ましく、また、硫酸塩の分解が非常に容
易であるという理由から、第２ＮＯx吸蔵材に含ませる
アルカリ金属としては、Ｋを用いるのが望ましい。Considering that the NO x occluding material has a high alkalinity and is excellent in NO x occluding ability, an alkali metal,
It is desirable to select from alkaline earth metals. SO
In terms of the characteristics that x is easy to adsorb and hard to separate,
Alkaline earth metals are superior to alkali metals. Taking this into consideration, it contained the alkaline earth metal to the 1NO x storage material, and it is desirable to include the alkali metal to the 2NO x occluding material. Further, because the amount of adsorbed NO x and SO x per mole is large, the first N
Examples of the alkaline earth metal contained in the O x storage material include Ba.
Preferably, K is used as the alkali metal to be contained in the second NO x storage material because the decomposition of sulfate is very easy.
【００２２】また、第１ＮＯx吸蔵材にＢａを用い、第
２ＮＯx吸蔵材にＫを用いた場合、ＢａのＳＯx離脱能は
約６５０℃にＫのＳＯx離脱能は約６００℃にそれぞれ
ピークをもつことから、エンジン制御により高温ストイ
キ〜リッチ雰囲気を作り出すことによって、上流側の第
１触媒と下流側の第２触媒の温度差から、両触媒ともＳ
Ｏx離脱能の大きい温度域を使用できることになり、よ
り一層硫黄被毒が抑制された触媒を構成できるという利
点をも有する。Further, using the Ba to the 1NO x storage material, the use of K to a 2NO x occluding material, SO x detachment capability of the SO x detachment ability of Ba is K to about 650 ° C. Each of about 600 ° C. Since a high temperature stoichiometric to rich atmosphere is created by controlling the engine because of the peak, the temperature difference between the first catalyst on the upstream side and the second catalyst on the downstream side causes both catalysts to have S
Since a temperature range in which O x desorption ability is large can be used, there is also an advantage that a catalyst in which sulfur poisoning is further suppressed can be formed.
【００２３】さらに、第１ＮＯx吸蔵材にＢａを用い、
第２ＮＯx吸蔵材にＫを用いた場合、ＢａのＮＯx吸蔵能
力は約２７０℃の温度条件においてそのピークを示し、
ＫのＮＯx吸蔵能力は約４００℃の温度条件においてそ
のピークを示すことから、触媒全体としてより幅広い温
度域において高いＮＯx吸蔵能力が確保できるという利
点もある。Further, Ba is used as the first NO x storage material,
When K is used as the second NO x storage material, the NO x storage capacity of Ba shows its peak at a temperature condition of about 270 ° C.
Since the NO x storage capacity of K shows its peak at a temperature condition of about 400 ° C., there is an advantage that a high NO x storage capacity can be secured in a wider temperature range as the whole catalyst.
【００２４】なお、第２ＮＯx吸蔵材にＫを用いた場
合、高温領域において、このＫはＴｉＯ2と反応しやす
い。このことを考慮すれば、第２触媒を構成する担体
は、ＺｒＯ2、Ａｌ2Ｏ3、ＭｇＡｌ2Ｏ4、ＣｅＯ2−Ｚｒ
Ｏ2複合酸化物等のＫと反応しにくい酸化物を単独であ
るいはこれらの２種以上を混合して構成することが望ま
しい。このような担体を用いることで、硫黄被毒を受け
難い触媒としつつ、ＮＯｘ吸蔵能力をより向上させるこ
とができる。When K is used as the second NO x occluding material, the K easily reacts with TiO 2 in a high temperature region. In view of this, the carriers constituting the second catalyst are ZrO 2 , Al 2 O 3 , MgAl 2 O 4 , CeO 2 —Zr
It is desirable to form an oxide which is difficult to react with K, such as an O 2 composite oxide, alone or as a mixture of two or more thereof. By using such a carrier, the NOx storage capacity can be further improved while making the catalyst less susceptible to sulfur poisoning.
【００２５】第１触媒および第２触媒における第１ＮＯ
x吸蔵材および第２ＮＯx吸蔵材の担持方法は、特に限定
されるものではなく、担持されるそれぞれのＮＯx吸蔵
材に応じた既に公知の方法にて行えばよい。ＮＯx吸蔵
材の担持量は、例えばモノリス型触媒の場合、第１触
媒、第２触媒とも、担体体積１リットルに対して０．０
５〜１モルの範囲とするのが望ましい。担持量が０．０
５モルより少ないと、ＮＯx吸蔵能力が小さくＮＯx浄化
性能が低下し、担持量が１モルを超える場合は、効果が
飽和することに加え、他成分量の低下による不具合が生
じる可能性があるからである。First NO in first and second catalysts
carrying method x storage material and the 2NO x storage material is not limited in particular, already may be performed by a known method according to each of the NO x storage material to be supported. Loading amount of the NO x storage material, for example, in the case of monolithic catalysts, the first catalyst, both the second catalyst, 0.0 with respect to the support thereon 1 g
It is desirable to set it in the range of 5 to 1 mol. Loading amount is 0.0
When 5 less than the molar, NO x storage capacity is lowered is small the NO x purification performance, if the supported amount exceeds 1 mol, in addition to the effect is saturated, possibility that a problem is caused by the decrease of the other components amount Because there is.
【００２６】本発明の排ガス浄化触媒をモノリス型触媒
として（ハニカム体として）形成する場合、第１触媒お
よび第２触媒はそれぞれの別体となるハニカム体として
形成され、その第１触媒と第２触媒とを間隔を隔てて配
置することが望ましい。モノリス型触媒を排ガス経路に
コンバータとして設置する場合、コンバータ内に１つの
ハニカム体を設置するときは、ハニカム体の中心部分の
み排ガス流量が多く、その周辺部のガス流量が減少し、
周辺部の貴金属およびＮＯx吸蔵材の利用率が低下する
という現象が起こり得る。そこで、第１触媒と第２触媒
とを別々のハニカム体に形成し、その間隔を隔てて設置
すれば、その間隔部において排ガスが乱流となり、背圧
が大きくなって排ガスのコンバータ内の通過抵抗が増加
することで、排ガスが均一に分散して触媒内を通過する
ことになり、特に第２触媒側では排ガスにその第２触媒
に排ガスが接触する時間が長くなる。このことにより、
触媒全体のＮＯx吸蔵量がより増加するすることとな
る。また、２つのハニカム体の間に間隔を設け触媒を分
断することにより、担体１個当たりの体積が減少するた
め担体の熱容量が下がる。このため、触媒は暖気性に優
れるので入りガス温度が低い場合（低温時）でも触媒活
性が上昇し、ＮＯx吸蔵量がより増加するすることとな
る。When the exhaust gas purifying catalyst of the present invention is formed as a monolith type catalyst (as a honeycomb body), the first catalyst and the second catalyst are formed as separate honeycomb bodies, and the first catalyst and the second catalyst are formed. It is desirable that the catalyst and the catalyst be arranged at an interval. When installing a monolithic catalyst as a converter in the exhaust gas path, when installing one honeycomb body in the converter, the exhaust gas flow rate is large only in the central portion of the honeycomb body, and the gas flow rate in the peripheral portion decreases,
Utilization of the noble metal and NO x storage material of the peripheral portion may occur a phenomenon that decreases. Therefore, if the first catalyst and the second catalyst are formed in separate honeycomb bodies and installed at intervals, the exhaust gas becomes turbulent at the intervals, the back pressure increases, and the exhaust gas passes through the converter. Due to the increase in the resistance, the exhaust gas is uniformly dispersed and passes through the catalyst. In particular, on the second catalyst side, the time during which the exhaust gas contacts the exhaust gas with the second catalyst increases. This allows
The NO x storage amount of the entire catalyst is further increased. Further, by separating the catalyst by providing an interval between the two honeycomb bodies, the heat capacity of the carrier is reduced because the volume per carrier is reduced. Therefore, the catalyst is increased if the gas temperature entering is excellent in warm resistance is low (low temperature), even catalytic activity, NO x storage amount is to be further increased.
【００２７】上記第１触媒と第２触媒との間隔は、５ｍ
ｍ以上２５ｍｍ以下とすることが望ましい。この間隔の
好適範囲は、後に示す実験により確かめられたものであ
り、この範囲において、本発明の排ガス浄化触媒は、よ
りＮＯx吸蔵能力に優れた排ガス浄化触媒となる。The distance between the first catalyst and the second catalyst is 5 m
It is desirable to set it to m or more and 25 mm or less. The preferred range of this interval has been confirmed by experiments described later. In this range, the exhaust gas purifying catalyst of the present invention is an exhaust gas purifying catalyst having more excellent NO x storage capacity.
【００２８】また、第１触媒と第２触媒とを別体のハニ
カム体とし、間隔を設けて配置する場合において、下流
側の第２触媒を上流側の第１触媒のハニカム体より高セ
ルの状態に形成することが望ましい。ハニカム体は、排
ガスが通過する多数の導通孔（導通路）を有し、高セル
の状態とは、断面において、単位面積当たりの導通孔の
数が多いことを意味する。言い換えれば、高セルの状態
とは、より細い導通路がよりたくさん存在する状態を意
味する。In the case where the first catalyst and the second catalyst are formed as separate honeycomb bodies and are arranged with a space therebetween, the downstream second catalyst may have a higher cell height than the upstream first catalyst honeycomb body. It is desirable to form it in a state. The honeycomb body has a large number of conductive holes (conductive paths) through which exhaust gas passes, and a high cell state means that the number of conductive holes per unit area is large in a cross section. In other words, the state of a high cell means a state in which there are more thinner conductive paths.
【００２９】第２触媒を第１触媒に比べて高セル化すれ
ば、上述した第１触媒と第２触媒との間隔部における排
ガスの圧力（背圧）がより上昇し、上記の排ガスが均一
に分散して触媒内を通過するという作用、特に第２触媒
側では排ガスにその第２触媒に排ガスが接触する時間が
長くなるという作用がより大きなものとなる。このこと
により、触媒全体のＮＯx吸蔵量がさらに増加するする
こととなる。If the second catalyst is made higher in cell size than the first catalyst, the pressure (back pressure) of the exhaust gas in the space between the first catalyst and the second catalyst is further increased, and the exhaust gas is made uniform. In particular, the effect of increasing the time during which the exhaust gas contacts the exhaust gas on the second catalyst side on the second catalyst side becomes greater. As a result, the NO x storage amount of the entire catalyst further increases.
【００３０】次に、上記本発明の排ガス浄化用触媒を使
用した本発明の排ガス浄化方法について説明する。本発
明の排ガス浄化方法は、リーンバーンエンジンからの排
ガスを浄化するもので、排ガス流路内に第１触媒が上流
側に第２触媒が下流側に位置するように上記排ガス浄化
触媒を配置し、間欠的に燃料ストイキ〜リッチ雰囲気と
なるリーンバーンエンジンからの排ガスに接触させ、燃
料リーン雰囲気で該排ガス中に含まれるＮＯxを該第１
ＮＯx吸蔵材および該第２ＮＯx吸蔵材に吸蔵させ、燃料
ストイキ〜リッチ雰囲気で該第１ＮＯx吸蔵材および該
第２ＮＯx吸蔵材から放出されたＮＯxを還元させること
を特徴とする。Next, the exhaust gas purifying method of the present invention using the exhaust gas purifying catalyst of the present invention will be described. The exhaust gas purifying method of the present invention purifies exhaust gas from a lean burn engine. The exhaust gas purifying catalyst is disposed in the exhaust gas passage such that the first catalyst is located upstream and the second catalyst is located downstream. intermittently fuel stoichiometric ~ brought into contact with the exhaust gas from a lean burn engine to be rich atmosphere, first the NO x contained in the exhaust gas in the fuel-lean atmosphere
The NO x storage material and is inserted in said 2NO x storage material, characterized in that to reduce the released NO x fuel stoichiometric ~ rich atmosphere from said 1NO x storage material and said 2NO x storage material.
【００３１】燃料リーン雰囲気では、排ガス中に含まれ
るＮＯが触媒上で酸化され、ＮＯ2をはじめとするＮＯx
となり、それがＮＯx吸蔵材に吸蔵されていく。そして
間欠的に燃料ストイキ〜リッチ雰囲気とされると、今度
は吸蔵されたＮＯxが放出され、それが触媒上でＨＣや
ＣＯと反応し還元される。In a fuel-lean atmosphere, NO contained in exhaust gas is oxidized on the catalyst, and NO x including NO 2
And it is stored in the NO x storage material. When the intermittently are fuel stoichiometric-rich atmosphere, this time is released occluded NO x, it is reacted with a reducing with HC and CO on the catalyst.
【００３２】排ガス中に含まれるＳＯxは、主成分をＳ
Ｏ2とするもので、このＳＯ2は、ＮＯと同様に、触媒上
で酸化されＳＯ3を主成分とするものになる。ＳＯ3は排
ガス中のＨ2Ｏと容易に反応して硫酸に変化し、ＮＯx吸
蔵材に容易に吸着するものとなる。吸着の方法は、ＮＯ
x吸蔵材がＢａである場合には、例えばＢａＳＯ4という
形になるものと考えられる。ここで、第１ＮＯx吸蔵材
はＳＯxの吸着能力が高くかつ離脱性能に劣るであるこ
とから、ＳＯxが吸着された第１ＮＯx吸蔵材に吸着し、
第１触媒に蓄積される。次いで間欠的に燃料ストイキ〜
リッチ雰囲気とされると、今度は吸着していたＳＯxは
放出され、それが触媒上でＨＣやＣＯと反応し還元さ
れ、ＳＯ2となって下流に向かうこととなる。SO x contained in the exhaust gas is mainly composed of S
Intended to be O 2, the SO 2, like NO, consisting of SO 3 is oxidized on the catalyst as a main component. SO 3 easily reacts with H 2 O in the exhaust gas to change to sulfuric acid, and easily adsorbs to the NO x storage material. The adsorption method is NO
When the x- occluding material is Ba, it is considered to be in the form of BaSO 4 , for example. Here, since the first NO x storage material has a high SO x adsorption capacity and is inferior in desorption performance, the first NO x storage material adsorbs to the first NO x storage material to which SO x is adsorbed,
It is stored on the first catalyst. Then intermittently fuel stoichiometric ~
When the atmosphere is set to be rich, the adsorbed SO x is released this time, and it reacts with HC and CO on the catalyst and is reduced to become SO 2 and travel downstream.
【００３３】本発明の排ガス浄化用触媒では、下流側の
第２触媒が有する第２ＮＯx吸蔵材にＳＯxの吸着能力に
劣りかつ離脱性能に優るものを用いているため、第１触
媒上で放出されたＳＯxは、この第２ＮＯx吸蔵材に吸着
することなく排気されることとなる。したがって、上記
排ガス浄化用触媒を用いた本発明の排ガス浄化方法で
は、触媒の硫黄被毒を抑制しつつ、効率的にＮＯxを吸
蔵できるため、耐久後であっても、ＮＯx浄化性能が劣
化しない排ガス浄化方法となる。[0033] In the exhaust gas purifying catalyst of the present invention, because of the use of those over the inferior and withdrawal performance adsorption capacity of the 2NO x storage material to SO x with the second catalyst downstream, at first on the catalyst The released SO x is exhausted without being adsorbed by the second NO x storage material. Thus, the exhaust gas purifying method of the present invention using the exhaust gas purifying catalyst, while suppressing the sulfur poisoning of the catalyst, for efficiently capable of absorbing the NO x, even after the durability test, is the NO x purification performance The exhaust gas purification method does not deteriorate.
【００３４】以上、本発明の排ガス浄化用触媒およびそ
れを用いた本発明の排ガス浄化方法の実施形態について
説明したが、上述した実施形態は一実施形態にすぎず、
本発明の排ガス浄化用触媒およびそれを用いた本発明の
排ガス浄化方法は、上記実施形態を始めとして、当業者
の知識に基づいて種々の変更、改良を施した形態で実施
することができる。Although the embodiments of the exhaust gas purifying catalyst of the present invention and the exhaust gas purifying method of the present invention using the same have been described above, the above-described embodiment is merely an embodiment,
The exhaust gas purifying catalyst of the present invention and the exhaust gas purifying method of the present invention using the same can be implemented in various modified and improved forms based on the knowledge of those skilled in the art, including the above-described embodiment.
【００３５】[0035]
【実施例】上記実施形態に基づいて、本発明の排ガス浄
化用触媒の一態様である排ガス浄化用触媒を、実施例と
して作製した。そして、第１触媒と第２触媒との位置関
係を逆転させた排ガス浄化用触媒と、触媒全体に均一な
ＮＯx吸蔵材を担持させた排ガス浄化用触媒とを、比較
例として作製し、実施例、比較例の排ガス浄化用触媒に
対して耐久促進試験を行い、それぞれの排ガス浄化用触
媒の試験後のＮＯx吸蔵量を比較することで、本発明の
排ガス浄化用触媒が耐硫黄被毒特性に優れていることを
確認した。EXAMPLES Based on the above embodiment, an exhaust gas purifying catalyst, which is one embodiment of the exhaust gas purifying catalyst of the present invention, was produced as an example. Then, an exhaust gas purifying catalyst in which the positional relationship between the first catalyst and the second catalyst was reversed, and an exhaust gas purifying catalyst in which a uniform NO x storage material was supported on the entire catalyst were produced as comparative examples. examples performs durability acceleration test relative to the exhaust gas purifying catalyst of Comparative example, by comparing the the NO x storage amount after the test of each of the exhaust gas purifying catalyst, the exhaust gas purifying catalyst is sulfur-poisoning of the present invention It was confirmed that the characteristics were excellent.
【００３６】さらに、本発明の排ガス浄化用触媒をモノ
リス型の触媒とした場合において、第１触媒と第２触媒
との間隔、第２触媒の担体を構成する多孔質酸化物、第
２触媒を構成するハニカム基材のセル数（導通孔数）の
変更によるＮＯx吸蔵量への影響を調査すべく、種々の
排ガス浄化用触媒を実施例として作製し、これらの触媒
に対しても耐久促進試験を行い、それぞれの排ガス浄化
用触媒の試験後のＮＯ x吸蔵量を比較した。以下、これ
らついて説明する。Further, the exhaust gas purifying catalyst of the present invention is
In the case of a squirrel-type catalyst, the first catalyst and the second catalyst
, The porous oxide constituting the carrier of the second catalyst,
2 The number of cells (the number of conductive holes) of the honeycomb substrate constituting the catalyst
NO due to changexTo investigate the effect on storage capacity,
Exhaust gas purification catalysts were prepared as examples, and these catalysts
Endurance promotion test for each exhaust gas purification
NO after test of catalyst xThe amount of occlusion was compared. Below, this
I will explain about it.
【００３７】［実施例１］ 〈実施例１の排ガス浄化用触媒〉本排ガス浄化用触媒の
第１触媒は、以下のように作製した。Example 1 <Exhaust Gas Purifying Catalyst of Example 1> The first catalyst of the present exhaust gas purifying catalyst was prepared as follows.
【００３８】ジルコニア粉末に硝酸ロジウム溶液を用い
て担持させ、これを乾燥、焼成してＲｈを担持したジル
コニア粉末を得た。Ｒｈの担持量は、Ｒｈ担持ジルコニ
ア粉末を１００ｗｔ％とした場合の０．４２ｗｔ％とし
た。次いでこのＲｈ担持ジルコニア粉末に、アルミナと
チタニアとの混合粉末を混合させた。混合比率は、アル
ミナ−チタニア混合粉末においてアルミナ：チタニアを
重量比で１：１とし、アルミナ−チタニア混合粉末：Ｒ
ｈ担持ジルコニア粉末を重量比で４：１とした。この混
合粉末にさらにセリアジルコニア複合酸化物を、アルミ
ナ−チタニア混合粉末：セリアジルコニア複合酸化物が
重量比で１０：１となるような割合で、混合した。この
粉末を所定の方法でスラリー化し、容量０．６５リット
ルのセラミック製ハニカムの担体基材にコートし、モノ
リス担体前駆体を作製した。コート量はモノリス担体前
駆体１リットル当たり２７０ｇとした。そして、このモ
ノリス担体前駆体を２５０℃で１５分間乾燥させた後、
５００℃で３０分間焼成し、モノリス担体を完成させ
た。A rhodium nitrate solution was supported on the zirconia powder, which was dried and fired to obtain a zirconia powder supporting Rh. The amount of Rh supported was 0.42 wt% when the amount of Rh-supported zirconia powder was 100 wt%. Next, a mixed powder of alumina and titania was mixed with the Rh-supported zirconia powder. The mixing ratio of alumina-titania mixed powder was 1: 1 in terms of weight ratio of alumina: titania, and alumina-titania mixed powder: R
The weight ratio of the h-supported zirconia powder was 4: 1. The mixed powder was further mixed with a ceria-zirconia composite oxide at a ratio such that the weight ratio of alumina-titania mixed powder: ceria-zirconia composite oxide was 10: 1. This powder was slurried by a predetermined method and coated on a ceramic honeycomb carrier substrate having a capacity of 0.65 liter to produce a monolith carrier precursor. The coating amount was 270 g per liter of the monolithic carrier precursor. Then, after drying this monolithic carrier precursor at 250 ° C. for 15 minutes,
It was baked at 500 ° C. for 30 minutes to complete the monolith carrier.
【００３９】このモノリス担体を、所定濃度の酢酸バリ
ウム水溶液に浸漬させ、Ｂａを担持させ、２５０℃で１
５分間乾燥させた後、５００℃で３０分間焼成した。Ｂ
ａの担持量は、モノリス担体１リットル当たり０．３モ
ルとした。次いで、これを濃度１５ｇ／リットルの重炭
酸アンモニウム水溶液に１５分間浸漬した後、１５分間
乾燥させた。次にこれにジニトロジアミン白金の硝酸溶
液を用いて、Ｐｔを担持させ、３００℃で１５分乾燥、
焼成した。Ｐｔの担持量は、モノリス担体１リットル当
たり２ｇとした。最後に所定濃度の硝酸リチウム水溶液
に浸漬させてリチウムを担持させ、２５０℃で１５分間
乾燥した後、５００℃で３０分間焼成して第１触媒を完
成させた。Ｌｉの担持量は、モノリス担体１リットル当
たり０．１モルとした。なお、本第１触媒は、主たるＮ
Ｏx吸蔵材として、Ｂａを担持させたものである。This monolithic carrier was immersed in an aqueous solution of barium acetate at a predetermined concentration to support Ba,
After drying for 5 minutes, it was baked at 500 ° C. for 30 minutes. B
The amount of a carried was 0.3 mol per liter of the monolithic carrier. Next, this was immersed in an aqueous solution of ammonium bicarbonate having a concentration of 15 g / liter for 15 minutes, and then dried for 15 minutes. Next, Pt was supported thereon using a nitric acid solution of dinitrodiamine platinum, and dried at 300 ° C. for 15 minutes.
Fired. The supported amount of Pt was 2 g per liter of the monolith carrier. Finally, it was immersed in an aqueous solution of lithium nitrate having a predetermined concentration to support lithium, dried at 250 ° C. for 15 minutes, and calcined at 500 ° C. for 30 minutes to complete the first catalyst. The supported amount of Li was 0.1 mol per liter of the monolithic carrier. The first catalyst is mainly composed of N
Ba is supported as an O x storage material.
【００４０】本排ガス浄化用触媒の第２触媒は、以下の
ように作製した。The second catalyst of the present exhaust gas purifying catalyst was prepared as follows.
【００４１】上記第１触媒の作製におけるモノリス担体
の完成までは同じ方法で行った。したがって、モノリス
担体は上記第１触媒と同じものを使用することとなる。
このモノリス担体に、ジニトロジアミン白金の硝酸溶液
を用いて、Ｐｔを担持させ、３００℃で１５分乾燥、焼
成した。Ｐｔの担持量は、モノリス担体１リットル当た
り２ｇとした。次に、これを所定濃度の酢酸カリウムと
硝酸リチウムとの混合水溶液に浸漬させてＫおよびＬｉ
を担持させ、２５０℃で１５分間乾燥した後、５００℃
で３０分間焼成して第２触媒を完成させた。ＫおよびＬ
ｉの担持量は、モノリス担体１リットル当たり、Ｋを
０．３モル、Ｌｉを０．１モルとした。なお、本第２触
媒は、主たるＮＯx吸蔵材として、Ｋを担持させたもの
である。The same method was used up to the completion of the monolith carrier in the preparation of the first catalyst. Therefore, the same monolithic carrier as the first catalyst is used.
Pt was supported on the monolithic carrier using a nitric acid solution of dinitrodiamineplatinum, and dried and calcined at 300 ° C. for 15 minutes. The supported amount of Pt was 2 g per liter of the monolith carrier. Next, this is immersed in a mixed aqueous solution of potassium acetate and lithium nitrate at a predetermined concentration to obtain K and Li.
And dried at 250 ° C. for 15 minutes.
For 30 minutes to complete the second catalyst. K and L
The supported amount of i was 0.3 mol of K and 0.1 mol of Li per liter of the monolithic carrier. The second catalyst has K as a main NO x storage material.
【００４２】上記第１触媒を排ガスの上流側に、上記第
２触媒を下流側に位置するように触媒コンバータに組み
込むことで実施例１の排ガス浄化用触媒を完成させた。The exhaust gas purifying catalyst of Example 1 was completed by incorporating the first catalyst into the catalytic converter so as to be located on the upstream side of the exhaust gas and the second catalyst on the downstream side.
【００４３】〈比較例１の排ガス浄化用触媒〉上記実施
例１で作製した第１触媒を排ガスの下流側に、第２触媒
を上流側に位置するように触媒コンバータに組み込むよ
うにして完成させた排ガス浄化用触媒である。実施例の
排ガス浄化用触媒と異なり、下流側に担持させたＮＯx
吸蔵材が、上流側に担持させたＮＯx吸蔵材よりも、硫
黄吸着しやすくかつ離脱しにくいものとなっている。<Catalyst for Purifying Exhaust Gas of Comparative Example 1> The first catalyst prepared in Example 1 was assembled in a catalytic converter so that the first catalyst was located downstream of the exhaust gas and the second catalyst was located upstream. Exhaust gas purifying catalyst. Unlike the exhaust gas purifying catalysts of Examples, NO x, which is supported on the downstream side
The storage material is more likely to adsorb sulfur and harder to be released than the NO x storage material carried on the upstream side.
【００４４】〈比較例２の排ガス浄化用触媒〉触媒の全
域にわたって、均一な硫黄吸着・離脱特性を持つように
ＮＯx吸蔵材を担持させた排ガス浄化用触媒である。こ
の触媒は以下のように作製した。[0044] over the entire <exhaust gas purifying catalyst of Comparative Example 2> catalysts, exhaust gas purifying catalyst supported with the NO x storage material to have a uniform sulfur adsorption and extraction properties. This catalyst was prepared as follows.
【００４５】担体基材にコートするスラリーの製造まで
は、上記実施例１の場合と同様とした。このスラリー
を、容量１．３リットルのセラミック製ハニカムの担体
基材にコートし、モノリス担体前駆体を作製した。コー
ト量はモノリス担体前駆体１リットル当たり２７０ｇと
した。そして、このモノリス担体前駆体を２５０℃で１
５分間乾燥させた後、５００℃で３０分間焼成し、モノ
リス担体を完成させた。The procedure up to the production of the slurry to be coated on the carrier substrate was the same as that in Example 1 above. This slurry was coated on a 1.3 liter ceramic honeycomb support substrate to produce a monolithic carrier precursor. The coating amount was 270 g per liter of the monolithic carrier precursor. Then, the monolithic carrier precursor is heated at 250 ° C. for 1 hour.
After drying for 5 minutes, it was baked at 500 ° C. for 30 minutes to complete the monolith carrier.
【００４６】このモノリス担体を、所定濃度の酢酸バリ
ウム水溶液に浸漬させ、Ｂａを担持させ、２５０℃で１
５分間乾燥させた後、５００℃で３０分間焼成した。Ｂ
ａの担持量は、モノリス担体１リットル当たり０．１５
モルとした。次いで、これを濃度１．５ｇ／リットルの
重炭酸アンモニウム水溶液に１５分間浸漬した後、１５
分間乾燥させた。次にこれにジニトロジアミン白金の硝
酸溶液を用いて、Ｐｔを担持させ、３００℃で１５分乾
燥、焼成した。Ｐｔの担持量は、モノリス担体１リット
ル当たり２ｇとした。最後に、これを所定濃度の酢酸カ
リウムと硝酸リチウムとの混合水溶液に浸漬させてＫお
よびＬｉを担持させ、２５０℃で１５分間乾燥した後、
５００℃で３０分間焼成した。ＫおよびＬｉの担持量
は、モノリス担体１リットル当たり、Ｋを０．１５モ
ル、Ｌｉを０．１モルとした。これを、触媒コンバータ
に組み込むことで、比較例２の排ガス浄化用触媒を完成
させた。The monolithic carrier was immersed in a barium acetate aqueous solution having a predetermined concentration to carry Ba,
After drying for 5 minutes, it was baked at 500 ° C. for 30 minutes. B
a is 0.15 per liter of the monolith carrier.
Mole. Next, this was immersed in an aqueous solution of ammonium bicarbonate having a concentration of 1.5 g / liter for 15 minutes,
Dried for minutes. Next, Pt was supported thereon using a nitric acid solution of dinitrodiamine platinum, and dried and calcined at 300 ° C. for 15 minutes. The supported amount of Pt was 2 g per liter of the monolith carrier. Finally, this is immersed in a mixed aqueous solution of potassium acetate and lithium nitrate at a predetermined concentration to support K and Li, and dried at 250 ° C. for 15 minutes.
It was baked at 500 ° C. for 30 minutes. The loading amounts of K and Li were 0.15 mol of K and 0.1 mol of Li per liter of the monolithic carrier. By incorporating this into a catalytic converter, the exhaust gas purifying catalyst of Comparative Example 2 was completed.
【００４７】〈耐硫黄被毒性の評価〉実施例１、比較例
１および比較例２のそれぞれの排ガス浄化用触媒を組み
込んだ触媒コンバータを、１．８リットルのリーンバー
ンエンジンに取り付け、市街走行を模擬したパターン
で、高硫黄濃度（硫黄＝２００ｐｐｍ）燃料を用い促進
耐久試験を５０時間行った。その後、触媒への入りガス
温度が３００℃〜４８０℃におけるそれぞれの排ガス浄
化触媒の触媒１個当たりのＮＯx吸蔵量を測定した。測
定結果を、図１に示す。<Evaluation of sulfur poisoning resistance> The catalytic converters incorporating the respective exhaust gas purifying catalysts of Example 1, Comparative Example 1 and Comparative Example 2 were attached to a 1.8-liter lean burn engine, and the vehicle was driven in a city. In a simulated pattern, an accelerated endurance test was performed for 50 hours using a high sulfur concentration (sulfur = 200 ppm) fuel. Thereafter, the gas temperature entering into the catalyst was measured the NO x storage amount of the catalyst per one of the respective exhaust gas purifying catalyst in 300 ° C. to 480 ° C.. FIG. 1 shows the measurement results.
【００４８】図１から明らかなように、実施例１の排ガ
ス浄化用触媒は、３００〜４８０℃の温度域のすべてに
おいて、２つの比較例の排ガス浄化用触媒より、耐久試
験後のＮＯx吸蔵量が大きいことが判る。特に、高温側
において、良好な結果を示していることが判る。したが
って、本発明の排ガス浄化用触媒は、耐硫黄被毒特性に
優れた触媒であることが確認できる。[0048] As is apparent from FIG. 1, the exhaust gas purifying catalyst of Example 1 in all temperature range of 300-480 ° C., from two comparative examples the catalyst for purification of exhaust gas, NO x storage after the durability test It turns out that the amount is large. In particular, it can be seen that good results are shown on the high temperature side. Therefore, it can be confirmed that the exhaust gas purifying catalyst of the present invention is a catalyst having excellent sulfur poisoning resistance.
【００４９】［実施例２］ 〈第１触媒および第２触媒の製造〉上記実施例１の場合
と同様の方法により、第１触媒を作製した。なおこのモ
ノリス型第１触媒は、円筒形のモノリス担体から構成さ
れているが、このモノリス担体は、直径１０３ｍｍφ、
長さ７５ｍｍであり、ハニカム体壁面の厚さは６ミル
（１ミルは約２５μｍ）、セル数（導通孔（導通路）の
数）は約４００セルのものとした。Example 2 <Production of First Catalyst and Second Catalyst> A first catalyst was produced in the same manner as in Example 1 above. The monolithic first catalyst is composed of a cylindrical monolithic carrier, and the monolithic carrier has a diameter of 103 mmφ,
The length of the honeycomb body was 75 mm, the thickness of the honeycomb body wall was 6 mil (1 mil was about 25 μm), and the number of cells (the number of conductive holes (conductive paths)) was about 400 cells.
【００５０】上記実施例１の場合と同様の方法により、
第２触媒を作製した。なおこのモノリス型第１触媒は、
円筒形のモノリス担体から構成されいるが、このモノリ
ス担体も、上記第１触媒のモノリス担体と同様、直径１
０３ｍｍφ、長さ７５ｍｍであり、ハニカム体壁面の厚
さは６ミル、セル数は約４００セルのものである。そし
て、この第２触媒をモノリス(１)とした。By the same method as in the first embodiment,
A second catalyst was prepared. This monolithic first catalyst is:
The monolithic support is composed of a cylindrical monolithic support.
It has a diameter of 03 mm, a length of 75 mm, a wall thickness of the honeycomb body of 6 mils, and a number of cells of about 400 cells. Then, the second catalyst was used as a monolith (1).
【００５１】次に、第２触媒の担体を構成する多孔質酸
化物の種類を変更し、種々の第２触媒を作製した。モノ
リス(１)の製造方法において（実施例１の場合の第２触
媒の製造方法において）、チタニア粉末をジルコニア粉
末に置換えたて作製した第２触媒をモノリス(２)と、以
下同様に、それぞれ、チタニア粉末をアルミナ粉末に置
換えたものをモノリス(３)と、チタニア粉末をジルコニ
ア粉末とアルミナ粉末との重量比１：１の混合粉末に置
換えたものをモノリス(４)と、チタニア粉末をスピネル
（ＭｇＡｌ2Ｏ4）粉末に置換えたものをモノリス(５)
と、チタニア粉末をスピネル粉末とジルコニア粉末との
重量比１：１の混合粉末に置換えたものをモノリス(６)
とした。Next, various kinds of second catalysts were prepared by changing the kind of the porous oxide constituting the carrier of the second catalyst. In the method for producing the monolith (1) (in the method for producing the second catalyst in the case of Example 1), the second catalyst produced by substituting the zirconia powder for the titania powder was referred to as the monolith (2). A monolith (3) in which titania powder was replaced by alumina powder; a monolith (4) in which titania powder was replaced by a mixed powder of zirconia powder and alumina powder at a weight ratio of 1: 1; Monolith (5) replaced with (MgAl 2 O 4 ) powder
And monolith (6) obtained by replacing titania powder with a mixed powder of spinel powder and zirconia powder at a weight ratio of 1: 1.
And
【００５２】次に、モノリス担体のセル数を変更して、
２種の第２触媒を作製した。上記モノリス(１)の製造に
おいて、ハニカム体壁面の厚さが３ミルで、６００セル
のモノリス担体を用いた第２触媒をモノリス(７)とし、
ハニカム体壁面の厚さが２ミルで、９００セルのモノリ
ス担体を用いた第２触媒をモノリス(８)とした。Next, by changing the number of cells of the monolithic carrier,
Two second catalysts were made. In the production of the monolith (1), the thickness of the honeycomb body wall surface is 3 mils, and the second catalyst using the monolith carrier of 600 cells is a monolith (7),
A monolith (8) was used as the second catalyst having a honeycomb body wall thickness of 2 mils and using a 900 cell monolith carrier.
【００５３】上記第１触媒および第２触媒である上記モ
ノリス(１)〜モノリス(８)の仕様について、下記表１に
まとめて示す。The specifications of the monoliths (1) to (8) as the first catalyst and the second catalyst are shown in Table 1 below.
【００５４】[0054]
【表１】 [Table 1]
【００５５】上記第１触媒を上流側に、モノリス(１)〜
モノリス(８)から選ばれる第２触媒の一つを下流側に配
置して、種々の実施例２の排ガス浄化用触媒を作製し
た。まず、上記第１触媒とモノリス(１)とを組み合わ
せ、両者の間に間隔を設けずに両者を配置した排ガス浄
化用触媒を実施例２−１の排ガス浄化用触媒とし、同様
にそれぞれ、両者の間に５ｍｍの間隔を設けて両者を配
置したものを実施例２−２の、１０ｍｍの間隔を設けた
ものを実施例２−３の、１５ｍｍの間隔を設けたものを
実施例２−４の、２０ｍｍの間隔を設けたものを実施例
２−５の、２５ｍｍの間隔を設けたものを実施例２−６
の、３０ｍｍの間隔を設けたものを実施例２−７の排ガ
ス浄化用触媒とした。The first catalyst is placed upstream of the monolith (1) to
By arranging one of the second catalysts selected from the monolith (8) on the downstream side, various exhaust gas purifying catalysts of Example 2 were produced. First, the first catalyst and the monolith (1) were combined, and an exhaust gas purifying catalyst in which both were arranged without providing an interval between them was used as the exhaust gas purifying catalyst of Example 2-1. In Example 2-2, the one in which both were disposed with a distance of 5 mm between them, the one in Example 2-3, in which a distance of 10 mm was provided, and the one in Example 2-3, in which a distance of 15 mm was provided. In Example 2-5, the one provided with an interval of 20 mm was used in Example 2-6.
The catalyst provided with an interval of 30 mm was used as the exhaust gas purifying catalyst of Example 2-7.
【００５６】次いで、上記第１触媒を上流側に、担体を
構成する多孔質酸化物を種々に変更した第２触媒である
モノリス(２)〜モノリス(６)のいずれかを、第１触媒と
の間隔を設けずに下流側に、それぞれ配置した排ガス浄
化用触媒を作製した。そして、モノリス(２)を用いた排
ガス浄化用触媒を実施例２−８の排ガス浄化用触媒と
し、同様にそれぞれ、モノリス(３)を用いたものを実施
例２−９の、モノリス(４)を用いたものを実施例２−１
０の、モノリス(５)を用いたものを実施例２−１１の、
モノリス(６)を用いたものを実施例２−１２の排ガス浄
化用触媒とした。Next, one of the monoliths (2) to (6) as the second catalyst in which the porous oxide constituting the carrier is variously changed is placed on the upstream side of the first catalyst and the first catalyst. Exhaust gas purifying catalysts were arranged on the downstream side without providing an interval. Then, the exhaust gas purifying catalyst using the monolith (2) was used as the exhaust gas purifying catalyst of Example 2-8, and similarly, the monolith (3) using the monolith (3) was used as the monolith (4) of Example 2-9. Example 2-1
0, using the monolith (5) in Example 2-11,
The catalyst using the monolith (6) was used as the exhaust gas purifying catalyst of Example 2-12.
【００５７】また、上記第１触媒を上流側に、その第１
触媒とセル数の異なる第２触媒であるモノリス(７)、モ
ノリス(８)のいずれかを、第１触媒との間隔を設けずに
下流側に、それぞれ配置した排ガス浄化用触媒を作製し
た。そして、モノリス(７)を用いた排ガス浄化用触媒を
実施例２−１３の排ガス浄化用触媒とし、モノリス(８)
を用いたものを実施例２−１４の排ガス浄化用触媒とし
た。Also, the first catalyst is placed upstream of the first catalyst.
Exhaust gas purifying catalysts were prepared in which either the monolith (7) or the monolith (8), which is a second catalyst having a different number of cells from the catalyst, was arranged downstream without providing an interval with the first catalyst. Then, the exhaust gas purifying catalyst using the monolith (7) was used as the exhaust gas purifying catalyst of Example 2-13, and the monolith (8)
Was used as the exhaust gas purifying catalyst of Example 2-14.
【００５８】さらに、上記第１触媒を上流側に、担体を
構成する多孔質酸化物を変更した第２触媒であるモノリ
ス(４)を下流側に用いた排ガス浄化用触媒においても、
第１触媒と第２触媒の間隔の影響を確認すべく、両者の
間に５ｍｍの間隔を設けて両者を配置したものを作製
し、これを実施例２−１５の排ガス浄化用触媒とした。
同様に、１０ｍｍの間隔を設けたものを実施例２−１６
の、１５ｍｍの間隔を設けたものを実施例２−１７の、
２０ｍｍの間隔を設けたものを実施例２−１８の、２５
ｍｍの間隔を設けたものを実施例２−１９の、３０ｍｍ
の間隔を設けたものを実施例２−２０の排ガス浄化用触
媒とした。Further, in the exhaust gas purifying catalyst using the first catalyst on the upstream side and the monolith (4) as the second catalyst in which the porous oxide constituting the carrier is changed on the downstream side,
In order to confirm the influence of the distance between the first catalyst and the second catalyst, a catalyst was prepared in which both were disposed with a distance of 5 mm therebetween, and this was used as the exhaust gas purifying catalyst of Example 2-15.
Similarly, the one provided with an interval of 10 mm was used in Example 2-16.
The one provided with a distance of 15 mm was used in Example 2-17.
Those provided with an interval of 20 mm were prepared according to Example 2-18, 25
In the case of Example 2-19, the distance of 30 mm
The catalyst provided with the intervals of was used as the exhaust gas purifying catalyst of Example 2-20.
【００５９】さらにまた、上記第１触媒を上流側に、セ
ル数の異なる第２触媒であるモノリス(７)を下流側に用
いた排ガス浄化用触媒においても、第１触媒と第２触媒
の間隔の影響を確認すべく、両者の間に５ｍｍの間隔を
設けて両者を配置したものを作製し、これを実施例２−
２１の排ガス浄化用触媒とした。同様に、１０ｍｍの間
隔を設けたものを実施例２−２２の、１５ｍｍの間隔を
設けたものを実施例２−２３の、２０ｍｍの間隔を設け
たものを実施例２−２４の、２５ｍｍの間隔を設けたも
のを実施例２−２５の、３０ｍｍの間隔を設けたものを
実施例２−２６の排ガス浄化用触媒とした。Further, in the exhaust gas purifying catalyst using the first catalyst on the upstream side and the monolith (7) as the second catalyst having a different number of cells on the downstream side, the distance between the first and second catalysts is also large. In order to confirm the influence of the above, a structure in which both were arranged at a distance of 5 mm between the two was prepared, and this was prepared in Example 2-
The catalyst for exhaust gas purification was No. 21. Similarly, the one provided with a 10 mm interval is of Example 2-22, the one provided with a 15 mm interval is of Example 2-23, the one provided with a 20 mm interval is of Example 2-24, and a 25 mm The catalyst provided with an interval was used as Example 2-25, and the one provided with an interval of 30 mm was used as an exhaust gas purifying catalyst of Example 2-26.
【００６０】上記実施例２−１〜実施例２−２２の排ガ
ス浄化用触媒の仕様について、下記表２にまとめて示
す。Table 2 below summarizes the specifications of the exhaust gas purifying catalysts of Examples 2-1 to 2-22.
【００６１】[0061]
【表２】 [Table 2]
【００６２】〈ＮＯx吸蔵能力の評価〉上記実施例２の
それぞれの排ガス浄化用触媒を組み込んだ触媒コンバー
タを、上記実施例１の場合に行ったのと、同一の条件で
促進耐久試験を行い、触媒への入りガス温度が４００℃
におけるそれぞれの排ガス浄化用触媒のＮＯx吸蔵量を
測定した。なお、実施例２−１の排ガス浄化用触媒は、
実施例１の排ガス浄化用触媒とその構成が近似してお
り、ＮＯx吸蔵量の絶対値は把握できている。そのた
め、ここからのＮＯx吸蔵量については、任意単位（arb
itrary unit：a.u）で表すものとする。<Evaluation of NO x storage capacity> An accelerated durability test was performed on the catalytic converter incorporating each exhaust gas purifying catalyst of the second embodiment under the same conditions as in the case of the first embodiment. Gas temperature to the catalyst is 400 ° C
The NO x storage amounts of the respective exhaust gas purifying catalysts were measured. Note that the exhaust gas purifying catalyst of Example 2-1 includes:
The structure of the exhaust gas purifying catalyst of Example 1 is similar to that of the exhaust gas purifying catalyst, and the absolute value of the NO x storage amount can be grasped. Therefore, the NO x storage amount from here is determined in arbitrary units (arb
Itrary unit: au).
【００６３】まず、第１触媒と第２触媒と間隔の大きさ
とＮＯx吸蔵量との関係について評価すべく、実施例２
−１〜実施例２−７の排ガス浄化用触媒のＮＯx吸蔵量
をグラフにして図２に示す。図２から明らかなように、
第１触媒と第２触媒との間にある程度の間隔を設けて両
者を配置することにより、両者に間隔を設けずに配置す
る場合と比較して、ＮＯx吸蔵量が増加することが確認
できる。また、図２から、本実施例の排ガス浄化用触媒
においては、その間隔を５ｍｍ以上２５ｍｍ以下とする
ことで、より大きなＮＯx吸蔵量の増加効果が得られる
ことも確認できる。First, in order to evaluate the relationship between the size of the space between the first catalyst and the second catalyst and the NO x storage amount, the second embodiment was used.
FIG. 2 is a graph showing the NO x storage amounts of the exhaust gas purifying catalysts of Examples 1-1 to 2-7. As is clear from FIG.
By arranging the first catalyst and the second catalyst with a certain space therebetween and by arranging them both, it can be confirmed that the NO x storage amount increases as compared with the case where both are arranged without the space therebetween. . From FIG. 2, it can also be confirmed that in the exhaust gas purifying catalyst of the present embodiment, by setting the interval to be 5 mm or more and 25 mm or less, a greater effect of increasing the NO x storage amount can be obtained.
【００６４】次いで、第２触媒の担体を構成する多孔質
酸化物の種類とＮＯx吸蔵量との関係について評価すべ
く、実施例２−１および実施例２−８〜実施例２−１２
の排ガス浄化用触媒のＮＯx吸蔵量をグラフにして図３
に示す。図３から判るように、実施例２−１の排ガス浄
化用触媒に比較して、実施例２−８〜実施例２−１２の
排ガス浄化用触媒は大きなＮＯx吸蔵能力を有する。実
施例２−１の排ガス浄化用触媒では、第２触媒の担体を
構成する酸化物としてチタニアを含み、これがＮＯx吸
蔵材であるＫとの反応性に富むことより、ＮＯx吸蔵能
力が若干低下するものと考えられる。したがって、第２
ＮＯx吸蔵材としてＫを用いた場合、第２触媒の担体は
チタニアを含まずに構成することが望ましいことが確認
できる。Next, in order to evaluate the relationship between the type of the porous oxide constituting the carrier of the second catalyst and the NO x storage amount, Examples 2-1 and 2-8 to 2-12 were evaluated.
FIG. 3 is a graph showing the NO x storage amount of the exhaust gas purifying catalyst of FIG.
Shown in As can be seen from FIG. 3, as compared to the exhaust gas purifying catalysts of Examples 2-1, the exhaust gas purifying catalyst of Example 2-8～ Example 2-12 has a large the NO x storage capacity. The exhaust gas purifying catalyst of Example 2-1, containing titania as oxides constituting the carrier of the second catalyst, which is higher than that highly reactive with K is the NO x storage material, the NO x storage capacity slightly It is thought to decrease. Therefore, the second
When K is used as the NO x storage material, it can be confirmed that it is desirable that the carrier of the second catalyst should not include titania.
【００６５】さらに、第２触媒のセル数とＮＯx吸蔵量
との関係について評価すべく、実施例２−１および実施
例２−１３〜実施例２−１４の排ガス浄化用触媒のＮＯ
x吸蔵量をグラフにして図４に示す。この図から判るよ
うに、第２触媒を第１触媒に比べて高セル化することに
より、ＮＯx吸蔵能力が向上することが確認できる。Further, in order to evaluate the relationship between the number of cells of the second catalyst and the NO x storage amount, the NO 2 of the exhaust gas purifying catalysts of Examples 2-1 and 2-13 to 2-14 were evaluated.
4 by the x storage amount in the graph. As it can be seen from this figure, by high cell as compared to the second catalyst in the first catalyst, it can be confirmed that improves the NO x storage capacity.
【００６６】また、第２触媒の担体を構成する多孔質酸
化物の種類を変更した場合または第２触媒を高セル化し
た場合において、第１触媒と第２触媒と間隔の大きさと
ＮＯ x吸蔵量との関係について評価すべく、実施例２−
１０および実施例２−１５〜実施例２−２０の排ガス浄
化用触媒のＮＯx吸蔵量をグラフにして図５に、実施例
２−１３および実施例２−２１〜実施例２−２６の排ガ
ス浄化用触媒のＮＯx吸蔵量をグラフにして図６に、そ
れぞれ示す。これらの図から判るように、いずれの場合
も、第１触媒と第２触媒との間にある程度の間隔を設け
て両者を配置することにより、両者に間隔を設けずに配
置する場合と比較して、ＮＯx吸蔵量が増加することが
確認できる。また、いずれの場合も、その間隔を５ｍｍ
以上２５ｍｍ以下とすることで、より大きなＮＯx吸蔵
量の増加効果が得られることが確認できる。Further, the porous acid constituting the carrier of the second catalyst is
When the kind of the compound is changed or the cell of the second catalyst is increased
The size of the gap between the first catalyst and the second catalyst
NO xTo evaluate the relationship with the occlusion amount,
10 and Examples 2-15 to 2-20
Catalyst NOxFIG. 5 is a graph showing the amount of occlusion, and FIG.
2-13 and Exhaust Gas of Examples 2-21 to 2-26
NO for purification catalystxFIG. 6 shows a graph of the amount of occlusion.
Shown respectively. As can be seen from these figures,
Also, a certain distance is provided between the first catalyst and the second catalyst.
By arranging them both, they can be arranged without any space between them.
NO compared toxIncreased storage capacity
You can check. In each case, the interval is 5 mm.
By setting the thickness to not less than 25 mm, larger NOxOcclusion
It can be confirmed that the effect of increasing the amount is obtained.
【００６７】[0067]
【発明の効果】本発明の排ガス浄化用触媒は、ＮＯx吸
蔵還元型の排ガス浄化用触媒を、排ガスの上流側に位置
する第１触媒と下流側に位置する第２触媒とに分け、第
１触媒に担持させるＮＯx吸蔵材を、第２触媒に担持さ
せるＮＯx吸蔵材よりも硫黄吸着しやすくかつ硫黄離脱
しにくい特性を持つように構成するものである。このよ
うな構成としたことにより、本発明の排ガス浄化用触媒
は、硫黄被毒が抑制され、耐久後もＮＯx吸蔵能力の低
下の少ない触媒となる。さらに、第１触媒と第２触媒と
を間隔を設けて配置することにより、ＮＯx吸蔵能力の
より高い排ガス浄化用触媒とすることが可能になる。The exhaust gas purifying catalyst of the present invention exhibits, divided NO x storage-and-reduction type exhaust gas purifying catalyst, and a second catalyst located in the first catalyst and the downstream side located upstream of the exhaust gas, the The NO x storage material supported on one catalyst is configured to have a characteristic of easily adsorbing sulfur and less likely to release sulfur than the NO x storage material supported on the second catalyst. By such a configuration, the exhaust gas purifying catalyst of the present invention is sulfur poisoning suppressed, and less catalyst having decreased also the NO x storage ability after endurance. Furthermore, by arranging the first catalyst and the second catalyst at an interval, it becomes possible to obtain an exhaust gas purifying catalyst having a higher NO x storage capacity.
【００６８】また、本発明の排ガス浄化方法は、上記本
発明の排ガス浄化用触媒を用い、間欠的に燃料ストイキ
〜リッチ雰囲気となるようなリーンバーンエンジンから
の排ガスを浄化する方法であり、この方法によれば、硫
黄被毒を抑制させつつ、排ガス中のＮＯxを効率よく浄
化させることができる。Further, the exhaust gas purifying method of the present invention is a method of intermittently purifying exhaust gas from a lean burn engine in which a fuel stoichiometric to rich atmosphere is obtained by using the exhaust gas purifying catalyst of the present invention. According to the method, while suppressing the sulfur poisoning, it is possible to purify NO x in the exhaust gas efficiently.
【図１】 実施例１および比較例１〜比較例２の排ガス
浄化用触媒の促進耐久試験後のＮＯx吸蔵量を示す。FIG. 1 shows the NO x storage amounts of the exhaust gas purifying catalysts of Example 1 and Comparative Examples 1 and 2 after an accelerated durability test.
【図２】 実施例２の排ガス浄化用触媒において、第１
触媒と第２触媒と間隔の大きさとＮＯx吸蔵量との関係
を示す。FIG. 2 shows a first example of the exhaust gas purifying catalyst of Example 2.
Shows the relationship between the size and the NO x storage amount of the catalyst and the second catalyst and spacing.
【図３】 実施例２の排ガス浄化用触媒において、第２
触媒の担体を構成する多孔質酸化物の種類とＮＯx吸蔵
量との関係を示す。FIG. 3 shows a second example of the exhaust gas purifying catalyst according to the second embodiment.
Shows the relationship between the type and the NO x storage amount of porous oxide constituting the catalyst support.
【図４】 実施例２の排ガス浄化用触媒において、第２
触媒のセル数とＮＯx吸蔵量との関係を示す。FIG. 4 shows a second example of the exhaust gas purifying catalyst according to the second embodiment.
4 shows the relationship between the number of catalyst cells and the amount of NO x stored.
【図５】 実施例２の排ガス浄化用触媒において、第２
触媒の担体を構成する多孔質酸化物の種類を変更した場
合の、第１触媒と第２触媒と間隔の大きさとＮＯx吸蔵
量との関係を示す。FIG. 5 shows a second example of the exhaust gas purifying catalyst according to the second embodiment.
Of changing the kind of the porous oxide constituting the catalyst support, showing the relationship between the size and the NO x storage amount of the first catalyst and the second catalyst and spacing.
【図６】 実施例２の排ガス浄化用触媒において、第２
触媒を高セル化した場合の、第１触媒と第２触媒と間隔
の大きさとＮＯx吸蔵量との関係を示す。FIG. 6 shows a second example of the exhaust gas purifying catalyst according to the second embodiment.
4 shows the relationship between the size of the gap between the first catalyst and the second catalyst and the NO x storage amount when the number of cells in the catalyst is increased.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｆ０１Ｎ 3/10 Ｆ０１Ｎ 3/20 Ｅ 3/20 3/28 ３０１Ｃ ３０１Ｑ 3/28 ３０１ Ｆ０２Ｄ 41/04 ３０５Ａ Ｂ０１Ｄ 53/36 １０４Ａ Ｆ０２Ｄ 41/04 ３０５ Ｂ０１Ｊ 23/56 ３０１Ａ (72)発明者 池田 靖夫 愛知県豊田市トヨタ町１番地 トヨタ自動 車株式会社内 (72)発明者 平山 洋 愛知県豊田市トヨタ町１番地 トヨタ自動 車株式会社内 Ｆターム(参考） 3G091 AA17 AA18 AB06 AB09 BA11 BA14 BA15 BA19 BA39 CB02 DA01 DA02 FB10 FB11 FB12 GA01 GA06 GA16 GA19 GA20 GB01X GB02Y GB03Y GB04Y GB05W GB06W GB07W GB10X GB16X HA08 HA18 HA46 HA47 3G301 HA01 HA02 JA15 JA25 JA33 JB09 MA01 MA11 NE13 NE14 NE15 4D048 AA02 AA06 AA13 AA18 AB01 AB02 AB05 AB07 BA01X BA02Y BA03X BA07X BA08X BA14X BA15X BA18Y BA19X BA30X BA31Y BA32Y BA33X BA34Y BA41X BA42X BB02 BC01 CA02 CC32 CC38 CC46 DA03 EA04 4G066 AA12B AA12C AA13B AA16B AA16C AA20C AA23C AA53A AB23A BA07 BA36 CA22 CA28 DA02 FA12 FA22 4G069 AA03 AA08 BA01A BA01B BA04B BA05A BA05B BB02A BB02B BB06A BB06B BC01A BC03B BC04B BC08A BC10A BC13A BC13B BC16A BC32A BC33A BC38A BC43A BC43B BC51A BC51B BC69A BC71B BC75B CA03 CA07 CA08 CA12 CA13 CA14 CA15 DA06 EA19 EC24 ED07 EE09 FA01 FA02 FA06 FB14 FB19 FB23 FC08 ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) F01N 3/10 F01N 3/20 E 3/20 3/28 301C 301Q 3/28 301 F02D 41/04 305A B01D 53/36 104A F02D 41/04 305 B01J 23/56 301A (72) Inventor Yasuo Ikeda 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Hiroshi Hirayama 1 Toyota Vehicle Town, Toyota City, Aichi Prefecture F-term in Toyota Motor Corporation (reference) 3G091 AA17 AA18 AB06 AB09 BA11 BA14 BA15 BA19 BA39 CB02 DA01 DA02 FB10 FB11 FB12 GA01 GA06 GA16 GA19 GA20 GB01X GB02Y GB03Y GB04Y GB05W GB06W GB07W GB10X GB16X HA08 HA18 HA45 JA33 JB09 MA01 MA11 NE13 NE14 NE15 4D048 AA02 AA06 AA13 AA18 AB01 AB02 AB05 AB07 BA01X BA02Y BA0 3X BA07X BA08X BA14X BA15X BA18Y BA19X BA30X BA31Y BA32. BB06B BC01A BC03B BC04B BC08A BC10A BC13A BC13B BC16A BC32A BC33A BC38A BC43A BC43B BC51A BC51B BC69A BC71B BC75B CA03 CA07 CA08 CA12 CA13 CA14 CA15 DA06 EA19 EC24 ED07 EE09 FA01 FA02 FA06 FB14 FB19 FB19 FB19 FB19
Claims (8)
担持された貴金属と、該担体に担持されたアルカリ金
属、アルカリ土類金属および希土類元素から選ばれる少
なくとも１種の第１ＮＯx吸蔵材とを含んでなり、排ガ
スの上流側に位置する第１触媒と、 多孔質酸化物からなる担体と、該担体に担持された貴金
属と、該担体に担持されたアルカリ金属、アルカリ土類
金属および希土類元素から選ばれる少なくとも１種の第
２ＮＯx吸蔵材とを含んでなり、排ガスの下流側に位置
する第２触媒と、 からなるＮＯx吸蔵還元型の排ガス浄化用触媒であっ
て、 前記第１ＮＯx吸蔵材は、前記第２ＮＯx吸蔵材よりも、
硫黄吸着しやすくかつ硫黄離脱しにくい特性を持つこと
を特徴とする排ガス浄化用触媒。1. A carrier comprising a porous oxide, a noble metal supported on the carrier, and at least one kind of first NO x storage selected from an alkali metal, an alkaline earth metal and a rare earth element supported on the carrier. A first catalyst located upstream of the exhaust gas, a carrier made of a porous oxide, a noble metal carried on the carrier, an alkali metal and an alkaline earth metal carried on the carrier and comprises at least one first 2NO x storage material selected from rare earth elements, a second catalyst located downstream of the exhaust gas, NO x storage reduction catalyst for purifying an exhaust gas consisting of the Part 1NO x storage component than the first 2NO x occluding material,
An exhaust gas purifying catalyst characterized by having a characteristic of easily adsorbing sulfur and hardly releasing sulfur.
属を含み、かつ、前記第２ＮＯx吸蔵材はアルカリ金属
を含む請求項１に記載の排ガス浄化用触媒。Wherein said first 1NO x storage material includes an alkaline earth metal, and said second 2NO x storage component catalyst for purification of exhaust gas according to claim 1 containing an alkali metal.
つ、前記第２ＮＯx吸蔵材はＫを含む請求項１に記載の
排ガス浄化用触媒。Wherein said first 1NO x storage material contains Ba, and the second 2NO x storage component catalyst for purification of exhaust gas according to claim 1 comprising K.
Ｏ3、ＭｇＡｌ2Ｏ4、ＣｅＯ2−ＺｒＯ2複合酸化物から
選ばれる１種以上からなる請求項３に記載の排ガス浄化
用触媒。4. The carrier of the second catalyst comprises ZrO 2 , Al 2
O 3, MgAl 2 O 4, CeO 2 -ZrO 2 catalyst for exhaust gas purification according to claim 3 comprising one or more selected from composite oxides.
ぞれ別体となるハニカム体として形成され、該第１触媒
と該第２触媒とが間隔を隔てて位置する請求項１ないし
請求項４のいずれかに記載の排ガス浄化用触媒。5. The first catalyst and the second catalyst are each formed as a separate honeycomb body, and the first catalyst and the second catalyst are located at an interval. The exhaust gas purifying catalyst according to any one of the above.
隔は、５ｍｍ以上２５ｍｍ以下である請求項５に記載の
排ガス浄化用触媒。6. The exhaust gas purifying catalyst according to claim 5, wherein the distance between the first catalyst and the second catalyst is 5 mm or more and 25 mm or less.
セルの状態に形成されている請求項５または請求項６に
記載の排ガス浄化用触媒。7. The exhaust gas purifying catalyst according to claim 5, wherein the second catalyst is formed in a higher cell state than the first catalyst.
担持された貴金属と、該担体に担持されたアルカリ金
属、アルカリ土類金属および希土類元素から選ばれる少
なくとも１種の第１ＮＯx吸蔵材とを含んでなり、排ガ
スの上流側に位置する第１触媒と、多孔質酸化物からな
る担体と、該担体に担持された貴金属と、該担体に担持
されたアルカリ金属、アルカリ土類金属および希土類元
素から選ばれる少なくとも１種の第２ＮＯx吸蔵材とを
含んでなり、排ガスの下流側に位置する第２触媒とから
なる排ガス浄化用触媒を、間欠的に燃料ストイキ〜リッ
チ雰囲気となるリーンバーンエンジンからの排ガスに接
触させ、燃料リーン雰囲気で該排ガス中に含まれるＮＯ
xを該第１ＮＯx吸蔵材および該第２ＮＯx吸蔵材に吸蔵
させ、燃料ストイキ〜リッチ雰囲気で該第１ＮＯx吸蔵
材および該第２ＮＯx吸蔵材から放出されたＮＯxを還元
させることを特徴とする排ガス浄化方法。8. A carrier comprising a porous oxide, a noble metal supported on the carrier, and at least one first NO x storage selected from an alkali metal, an alkaline earth metal and a rare earth element supported on the carrier. A first catalyst positioned upstream of the exhaust gas, a support made of a porous oxide, a noble metal supported on the support, an alkali metal and an alkaline earth metal supported on the support. and comprises at least one first 2NO x storage material selected from rare earth elements, an exhaust gas purifying catalyst comprising a second catalyst located downstream of the exhaust gas, the intermittent fuel stoichiometric-rich atmosphere The exhaust gas from the lean burn engine is brought into contact with the exhaust gas, and NO contained in the exhaust gas in a fuel-lean atmosphere.
The x is occluded in said 1NO x storage material and said 2NO x storage material, characterized in that to reduce the released NO x fuel stoichiometric ~ rich atmosphere from said 1NO x storage material and said 2NO x storage material Exhaust gas purification method.
Priority Applications (1)
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|---|---|---|---|
| JP2000006033A JP3846139B2 (en) | 1999-04-22 | 2000-01-11 | Exhaust gas purification catalyst and exhaust gas purification method using the same |
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|---|---|---|---|
| JP11-114680 | 1999-04-22 | ||
| JP11468099 | 1999-04-22 | ||
| JP2000006033A JP3846139B2 (en) | 1999-04-22 | 2000-01-11 | Exhaust gas purification catalyst and exhaust gas purification method using the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2001000863A true JP2001000863A (en) | 2001-01-09 |
| JP3846139B2 JP3846139B2 (en) | 2006-11-15 |
Family
ID=26453378
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|---|---|---|---|
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Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001062294A (en) * | 1999-08-25 | 2001-03-13 | Toyota Motor Corp | Exhaust gas cleaning catalyst |
| JP2002126453A (en) * | 2000-10-25 | 2002-05-08 | Toyota Motor Corp | Waste gas cleaning device |
| JP2003038936A (en) * | 2001-07-30 | 2003-02-12 | Toyota Motor Corp | Exhaust gas purifying apparatus |
| JP2004008977A (en) * | 2002-06-07 | 2004-01-15 | Valtion Teknillinen Tutkimuskeskus | Method for catalytically removing nitrogen oxide and apparatus therefor |
| JP2006175299A (en) * | 2004-12-20 | 2006-07-06 | Toyota Central Res & Dev Lab Inc | Nox occlusion material, its carrying method and nox occlusion reduction type catalyst |
| WO2006103914A1 (en) | 2005-03-29 | 2006-10-05 | Yanmar Co., Ltd. | Exhaust gas purifier |
| WO2007052817A1 (en) * | 2005-11-07 | 2007-05-10 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purification apparatus |
| WO2007072690A1 (en) * | 2005-12-22 | 2007-06-28 | Cataler Corporation | Catalyst for exhaust gas clean-up |
| JP2009248057A (en) * | 2008-04-10 | 2009-10-29 | Toyota Motor Corp | Catalyst for exhaust gas purification |
| JP2010104910A (en) * | 2008-10-30 | 2010-05-13 | Toyota Motor Corp | S (sulfur)-storage catalyst |
| JP2011036824A (en) * | 2009-08-17 | 2011-02-24 | Mazda Motor Corp | Catalyst for cleaning exhaust, and method of producing the same |
| JP2012002459A (en) * | 2010-06-18 | 2012-01-05 | Miura Co Ltd | Combustion device, and catalyst |
| US20170167336A1 (en) * | 2015-12-11 | 2017-06-15 | Hyundai Motor Company | Apparatus for purifying exhaust gas |
| JP2020056382A (en) * | 2018-10-04 | 2020-04-09 | 三菱自動車工業株式会社 | Exhaust emission control device |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06229230A (en) * | 1993-02-03 | 1994-08-16 | Toyota Motor Corp | Exhaust emission control device for internal combustion engine |
| JPH08117601A (en) * | 1994-10-21 | 1996-05-14 | Toyota Central Res & Dev Lab Inc | Exhaust gas purification catalyst and method for purifying exhaust gas |
| JPH0985093A (en) * | 1995-09-26 | 1997-03-31 | Toyota Motor Corp | Catalyst for cleaning exhaust gas |
| JPH10317949A (en) * | 1998-06-22 | 1998-12-02 | Nissan Motor Co Ltd | Exhaust emission control device |
| JPH1122453A (en) * | 1997-05-02 | 1999-01-26 | Degussa Ag | Exhaust emission control system for diesel engine |
| JPH1157406A (en) * | 1997-08-22 | 1999-03-02 | Mitsubishi Motors Corp | Exhaust gas cleaning device |
| JPH11104493A (en) * | 1997-10-02 | 1999-04-20 | Nissan Motor Co Ltd | Catalyst for purifying exhaust gas and its use |
-
2000
- 2000-01-11 JP JP2000006033A patent/JP3846139B2/en not_active Expired - Lifetime
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06229230A (en) * | 1993-02-03 | 1994-08-16 | Toyota Motor Corp | Exhaust emission control device for internal combustion engine |
| JPH08117601A (en) * | 1994-10-21 | 1996-05-14 | Toyota Central Res & Dev Lab Inc | Exhaust gas purification catalyst and method for purifying exhaust gas |
| JPH0985093A (en) * | 1995-09-26 | 1997-03-31 | Toyota Motor Corp | Catalyst for cleaning exhaust gas |
| JPH1122453A (en) * | 1997-05-02 | 1999-01-26 | Degussa Ag | Exhaust emission control system for diesel engine |
| JPH1157406A (en) * | 1997-08-22 | 1999-03-02 | Mitsubishi Motors Corp | Exhaust gas cleaning device |
| JPH11104493A (en) * | 1997-10-02 | 1999-04-20 | Nissan Motor Co Ltd | Catalyst for purifying exhaust gas and its use |
| JPH10317949A (en) * | 1998-06-22 | 1998-12-02 | Nissan Motor Co Ltd | Exhaust emission control device |
Cited By (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001062294A (en) * | 1999-08-25 | 2001-03-13 | Toyota Motor Corp | Exhaust gas cleaning catalyst |
| JP2002126453A (en) * | 2000-10-25 | 2002-05-08 | Toyota Motor Corp | Waste gas cleaning device |
| JP2003038936A (en) * | 2001-07-30 | 2003-02-12 | Toyota Motor Corp | Exhaust gas purifying apparatus |
| JP2004008977A (en) * | 2002-06-07 | 2004-01-15 | Valtion Teknillinen Tutkimuskeskus | Method for catalytically removing nitrogen oxide and apparatus therefor |
| JP4534749B2 (en) * | 2004-12-20 | 2010-09-01 | 株式会社豊田中央研究所 | NOx storage material, method for supporting the same, and NOx storage reduction catalyst |
| JP2006175299A (en) * | 2004-12-20 | 2006-07-06 | Toyota Central Res & Dev Lab Inc | Nox occlusion material, its carrying method and nox occlusion reduction type catalyst |
| WO2006103914A1 (en) | 2005-03-29 | 2006-10-05 | Yanmar Co., Ltd. | Exhaust gas purifier |
| EP2279785A2 (en) | 2005-03-29 | 2011-02-02 | Yanmar Co. Ltd. | Exhaust gas purifier |
| WO2007052817A1 (en) * | 2005-11-07 | 2007-05-10 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purification apparatus |
| US8187996B2 (en) | 2005-12-22 | 2012-05-29 | Cataler Corporation | Exhaust gas-purifying catalyst |
| JP2007167780A (en) * | 2005-12-22 | 2007-07-05 | Cataler Corp | Catalyst for exhaust gas purification |
| WO2007072690A1 (en) * | 2005-12-22 | 2007-06-28 | Cataler Corporation | Catalyst for exhaust gas clean-up |
| JP2009248057A (en) * | 2008-04-10 | 2009-10-29 | Toyota Motor Corp | Catalyst for exhaust gas purification |
| JP2010104910A (en) * | 2008-10-30 | 2010-05-13 | Toyota Motor Corp | S (sulfur)-storage catalyst |
| JP2011036824A (en) * | 2009-08-17 | 2011-02-24 | Mazda Motor Corp | Catalyst for cleaning exhaust, and method of producing the same |
| JP2012002459A (en) * | 2010-06-18 | 2012-01-05 | Miura Co Ltd | Combustion device, and catalyst |
| US20170167336A1 (en) * | 2015-12-11 | 2017-06-15 | Hyundai Motor Company | Apparatus for purifying exhaust gas |
| US10036293B2 (en) * | 2015-12-11 | 2018-07-31 | Hyundai Motor Company | Apparatus for purifying exhaust gas |
| JP2020056382A (en) * | 2018-10-04 | 2020-04-09 | 三菱自動車工業株式会社 | Exhaust emission control device |
| JP7167614B2 (en) | 2018-10-04 | 2022-11-09 | 三菱自動車工業株式会社 | Exhaust gas purifier |
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