CN1311893C - Catalyst for purifying exhaust gases - Google Patents
Catalyst for purifying exhaust gases Download PDFInfo
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- CN1311893C CN1311893C CNB2004100871297A CN200410087129A CN1311893C CN 1311893 C CN1311893 C CN 1311893C CN B2004100871297 A CNB2004100871297 A CN B2004100871297A CN 200410087129 A CN200410087129 A CN 200410087129A CN 1311893 C CN1311893 C CN 1311893C
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- 239000003054 catalyst Substances 0.000 title claims abstract description 145
- 239000007789 gas Substances 0.000 title abstract description 8
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 69
- 238000011068 loading method Methods 0.000 claims abstract description 27
- 239000011159 matrix material Substances 0.000 claims description 47
- 238000000576 coating method Methods 0.000 claims description 35
- 239000011248 coating agent Substances 0.000 claims description 32
- 238000011049 filling Methods 0.000 claims description 6
- 230000003197 catalytic effect Effects 0.000 abstract description 7
- 231100000572 poisoning Toxicity 0.000 abstract description 7
- 230000000607 poisoning effect Effects 0.000 abstract description 7
- 239000000758 substrate Substances 0.000 abstract description 4
- 239000000126 substance Substances 0.000 abstract description 2
- 239000004615 ingredient Substances 0.000 abstract 5
- 239000011247 coating layer Substances 0.000 abstract 2
- 238000006243 chemical reaction Methods 0.000 description 19
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 18
- 239000010948 rhodium Substances 0.000 description 15
- 239000000463 material Substances 0.000 description 14
- 239000002912 waste gas Substances 0.000 description 13
- 229910052697 platinum Inorganic materials 0.000 description 12
- 229910052703 rhodium Inorganic materials 0.000 description 12
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 11
- 230000001473 noxious effect Effects 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 10
- 238000002474 experimental method Methods 0.000 description 10
- 238000010521 absorption reaction Methods 0.000 description 9
- 229910052748 manganese Inorganic materials 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 229910052745 lead Inorganic materials 0.000 description 8
- 238000000034 method Methods 0.000 description 7
- 239000002002 slurry Substances 0.000 description 7
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 6
- 239000005864 Sulphur Substances 0.000 description 5
- 230000001413 cellular effect Effects 0.000 description 5
- 239000000446 fuel Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 230000008021 deposition Effects 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 229910002091 carbon monoxide Inorganic materials 0.000 description 3
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 3
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 229910052878 cordierite Inorganic materials 0.000 description 3
- 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 3
- 239000002574 poison Substances 0.000 description 3
- 231100000614 poison Toxicity 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
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- ZXVONLUNISGICL-UHFFFAOYSA-N 4,6-dinitro-o-cresol Chemical group CC1=CC([N+]([O-])=O)=CC([N+]([O-])=O)=C1O ZXVONLUNISGICL-UHFFFAOYSA-N 0.000 description 1
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- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
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- 231100000566 intoxication Toxicity 0.000 description 1
- 230000035987 intoxication Effects 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000010721 machine oil Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen 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
- 238000000746 purification Methods 0.000 description 1
- 238000011160 research Methods 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
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Landscapes
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
Abstract
A catalyst for purifying exhaust gases includes a substrate including an exhaust-gas passage, a coating layer formed on the exhaust-gas passage, and a catalytic ingredient loaded on the coating layer. A loading density of the catalytic ingredient on an upstream area discriminated from a downstream area by a predetermined length from an upstream end of the substrate is greater than a loading density of the catalytic ingredient on the downstream area. The catalytic ingredient is loaded more on the downstream area of the exhaust-gas passage than on the upstream area thereof. Thus, it is possible to suppress the catalytic ingredient being poisoned by poisoning substances.
Description
Background of invention
Invention field
The present invention relates to a kind of catalyst that is used for purifying exhaust air that is mainly used in automotive field.Or rather, the present invention relates to the catalyst that is used for purifying exhaust air that a kind of performance that can suppress to be caused by poisoning descends.
Association area is described
Management of vehicle exhaust systems has been equipped the multiple catalyst that is used for purifying exhaust air (for example oxidation catalyst, three-way catalyst and NO
xAbsorption and reducing catalyst) to remove HC, CO and the NO in the waste gas by oxidation and/or reduction
xFor example, adopt the cellular matrix that constitutes by cordierite or metal forming to prepare three-way catalyst in the following manner.Use aluminium oxide and/or ceria on the cellular channel surface of matrix, to form coating.Then, for example Pt and Rh fill on the described coating with catalyst component.The three-way catalyst of gained has been used for the exhaust environment that produced by air-fuel mixture burning, and the air-fuel of wherein said air-fuel mixture (A/F) Chemical Measurement ratio is controlled in about 14.6.Therefore, three-way catalyst purifies HC and CO by oxidation, and purifies NO by reduction simultaneously
x
When use contains additive for example during the fuel of Pb and Mn, can contain Pb and Mn component in the waste gas.Consequent shortcoming is that the catalyst component active site is covered by Pb and Mn component in the catalyst, thereby makes its active decline.In addition, known that P contained in the machine oil, Zn and Ca can cause similar shortcoming.
Japanese unexamined patent publication No. publication (KOKAI) No.2002-172,329 disclose and have been used for collecting the catalyst structure of trapping layer that waste gas is poisoned the component of catalyst a kind of comprising.Described trapping layer is placed in NO
xNear the upstream end surface of absorption and reducing catalyst.This catalytic structure can suppress NO
xThe NO of absorption and reducing catalyst
xAbsorbed component is poisoned by sulphur, because described trapping layer can be collected the sulphur component.
In this patent publications disclosed trapping layer contain can with the capture component of sulphur component reaction with the trap sulfur component, thereby this only can suppress to adsorb NO
xThe intoxication that component causes because of sulphur.Yet this patent publications had not both had explanation not have hint can suppress for example poisoning of Pt of catalyst component yet.And except sulphur, this patent publications is not mentioned other noxious material for example Pb and Mn yet.
Summary of the invention
The present invention forms under this background.Thereby, the objective of the invention is to suppress catalyst component because of noxious material for example Pb and Mn cause to poison its performance descended, improve the durability of the catalyst that is used for purifying exhaust air thus.
The catalyst that is used for purifying exhaust air of the present invention contains:
The matrix that comprises exhaust steam passage;
The coating that on described exhaust steam passage, forms; With
Fill in the catalyst component on the described coating,
Wherein the loading density of catalyst component is greater than the loading density of catalyst component in the upstream region in the downstream area, and upstream region and downstream area are distinguished by the predetermined length that starts from the matrix upstream extremity.
The upstream region that it is desirable to exhaust steam passage does not contain the catalyst component of described filling.
In addition, preferably start from the predetermined length of upstream extremity less than 30% of described matrix length overall.In addition, the predetermined length that preferably starts from upstream extremity is in the scope of 5-20% of described matrix length overall.
In addition, preferably start from the predetermined length of upstream extremity less than 31.5mm.In addition, the predetermined length that preferably starts from upstream extremity is in the scope of 5-21mm.
The catalyst that is used for purifying exhaust air of the present invention can suppress noxious material, and for example Pb and Mn poison catalyst component.Thereby even behind the experience durability experiment, catalyst of the present invention also can show high activity, and this is to have obtained inhibition because the activity of catalyst component descends.
Especially, when the upstream region length of the exhaust steam passage of the catalyst component that does not contain described filling less than the matrix length overall 30% the time, the activity that catalyst of the present invention shows is equal to or higher than the activity that catalyst component wherein fills in the conventional catalyst on the whole length.
The accompanying drawing summary
When passing through when considering together can more fully be familiar with the present invention and its many advantages easily and understand these contents simultaneously better with reference to following detailed description with describing in detail in conjunction with the accompanying drawings, all these constitute the part of present disclosure.
Fig. 1 is for being used for the cross-sectional view of the catalyst structure of purifying exhaust air in the rough indication embodiment of the invention 1.
Fig. 2 is used to explain the key diagram that how to obtain the cross conversion rate.
Fig. 3 is used to illustrate CO-NO
xCross conversion rate and exhaust steam passage upstream region length are with respect to the curve map of the relation between the ratio of matrix length overall.
Detailed description of the preferred embodiments
After the present invention made general description, can be by obtaining further understanding of the present invention with reference to particular preferred embodiment, the described preferred embodiment that provides here only is used for illustration purpose, is not in order to limit the scope of appended claims.
According to the research that the inventor carries out, can find out obviously that when catalyst is contacted with the waste gas that contains Pb and Mn for example Pb and Mn cause that catalyst component is poisoned and appear at the upstream portion of catalyst in the active set that its performance is descended because of noxious material.Therefore, at the catalyst that is used for purifying exhaust air of the present invention, the loading density of catalyst component is greater than the loading density of upstream region in the downstream area, and upstream region and downstream area are distinguished by the predetermined length that starts from the matrix upstream extremity.Thereby, because the loadings of catalyst component is less and descend because of the murder by poisoning of noxious material makes the performance of catalyst component probably in described upstream region in upstream region, and the loadings of catalyst component is more in the downstream area of the exhaust steam passage beyond the upstream region, is poisoned by noxious material so can suppress catalyst component.Thereby catalyst of the present invention not only can effectively utilize catalyst component, and activity descends after can being suppressed at the experience durability experiment.
Noxious material mainly adsorbs or is deposited on the upstream region of exhaust steam passage.Thereby, when the loading density of catalyst component in the upstream region less than the downstream area of its exhaust steam passage beyond upstream region in during the loading density of catalyst component, can suppress catalyst component and descend because of the poisoning performance.For example, can make the loading density of catalyst component in the upstream region with the loading density of specific degrees less than catalyst component in the downstream area.Yet, preferably along near the upstream extremity direction of matrix from how to few loading density that progressively or little by little reduces catalyst component the upstream region, because upstream region is more likely poisoned than downstream area.In addition, further preferably in the fast part of the waste gas flow velocity of upstream region, reduce the loading density of catalyst component, because the performance decline situation of catalyst component more likely appears at the wherein fast catalyst member of waste gas flow velocity consumingly.
Yet, be difficult to make the loading density of catalyst component to distribute usually according to production technology.Thereby, preferably the catalyst that is used for purifying exhaust air of the present invention is arranged, make the upstream region of exhaust steam passage can not contain the catalyst component of filling.This catalyst can prepare extremely to be easy to mode.Thus, adopt this structure can prevent fully that the upstream region of exhaust steam passage from descending because of poisoning causes performance.And, can will wait that the catalyst component that fills in upstream region fills in the downstream area of exhaust steam passage in addition, thereby make catalyst of the present invention can fully show its activity.
It should be noted that noxious material is the upstream region that is deposited on exhaust steam passage gradually.Yet the deposition of noxious material can not cause any problem, and this is because when deposition reaches a certain amount of, and the noxious material of deposition will be discharged to the flow velocity increase of outside and waste gas with waste gas.
The length of the upstream region of exhaust steam passage can be preferably less than 30% of matrix length overall.According to the experiment that the inventor did, if discovery does not contain the zone length of the catalyst component of filling and surpasses 30% of matrix length overall, so with those wherein the conventional catalyst that fills on the whole substrate length of catalyst component compare, the activity of such catalysts that obtains behind the experience durability experiment can reduce.Its reason is not clear.Yet, can believe content as described below.The loadings absolute value of supposing catalyst component in the catalyst of the present invention is identical with the loadings absolute value of catalyst component in the conventional catalyst, and the loading density of catalyst component can increase in the downstream area of catalyst of the present invention greatly so.As a result, behind catalyst of the present invention experience durability experiment, be catalyzed into branch germination takes place, thereby make the decreased number of active site.
In addition, the length that particularly preferably is the upstream region of exhaust steam passage can be in the scope of 5-20% of matrix length overall.When the length of the upstream region of exhaust steam passage falls within this scope, with those wherein the conventional catalyst that fills on the whole substrate length of catalyst component compare, the activity of such catalysts that is used for purifying exhaust air of the present invention can improve more.
Make cellular described matrix or foam-like.Can adopt following material to prepare matrix: by the heat-stable ceramic honeycomb or the foaming structure that make of cordierite for example; The honeycomb that makes by metal forming; With the foaming structure that makes by metallic fiber.The hole density that it should be noted that matrix and porosity can be identical with those of matrix commonly used.
Coating can be formed by a kind of composition that is selected from following material: aluminium oxide, titanium dioxide, zirconia, ceria, silica or described hopcalite.As selection, coating can be formed by the composite oxides that multiple oxide constitutes.Can adopt the described coating of conventional feedstock production.Decide according to the type of catalyst, preferably select optimum feed stock.For example, when the catalyst that is used for waste gas purification of the present invention is become three-way catalyst, preferably aluminium oxide and ceria or ceria-zirconia composite oxides of having absorption and discharging the oxygen ability are mixed, and the mixture of employing gained prepares coating.
Even it is to be noted when the upstream region of exhaust steam passage does not form coating, the catalyst that is used for purifying exhaust air of the present invention of gained can work and realize its advantage equally.Therefore, when making the upstream region of exhaust steam passage not contain the catalyst component of filling when catalyst of the present invention is arranged, preferably do not form coating at upstream region.For this arranging, can reduce the flowing resistance that puts on waste gas in the upstream region, thereby reduce the pressure loss.And the hole density in increasing upstream region is so that the pressure loss is when equaling the pressure loss of conventional catalyst, the aperture surface area increase that contact with waste gas.Therefore, can increase absorption or the deposition of noxious material in upstream region, make that can further suppress catalyst component descends because of the poisoning performance in downstream area.
With the same in a conventional manner, can use slurry and dry then and calcine slurry formation coating by adopting coating method (wash coating).According to coating method, can not form coating extremely to be easy to mode, because coating method can not make slurry be deposited on upstream region at the upstream region of exhaust steam passage.It is to be noted that the formation amount of coating can be usual amounts, for example counts 100-300g with the 1L matrix.
Type and the application that is used for the catalyst of purifying exhaust air according to the present invention decided, and for example Pt, Rh, Pd, Ir and Ru are used as catalyst component can suitably to select and use noble metal.And in some applications, for example Fe, Ni, Co, Cu and W are used as catalyst component can to use transition metal.The loadings of catalyst component can be 0.1-10g in the 1L matrix, but can be according to the present invention the type and the application of catalyst suitably change.
Can catalyst component be filled on the described coating by suction method or the absorption method identical with usual manner.In the suction method, the solution impregnation coating with wherein dissolving the compound with catalyst component is dried then and calcines.In described absorption method, will have coating of material and immerse in the solution that wherein dissolves compound and taking-up with catalyst component, be dried, then calcining.As selection, can by suction method or absorption method catalyst component be filled in the oxide powder that is used to prepare coating in advance, and can adopt the catalytic powder of gained to form coating.
Embodiment
To be described in detail the present invention according to embodiment and comparative example below.
Embodiment 1
Fig. 1 rough indication according to the cross-sectional view of the catalyst that is used for purifying exhaust air of the embodiment of the invention 1.This catalyst is a three-way catalyst, and it contains cellular matrix 1, and coating 2 only that form on the downstream area of matrix 1 and that be filled with catalyst component is to fill in Pt on the coating 2 and Rh as catalyst component.The length overall of matrix 1 is 105mm.It is 5.25mm (be matrix 1 length overall 5%) extends to the downstream surface from upstream end surface upstream region 10 that matrix 1 comprises length.It should be noted that on upstream region 10, not form coating 2, and Pt and Rh are not filled on the upstream region 10.
Hereinafter will describe the Preparation of catalysts method that is used for purifying exhaust air, rather than describe the structure of the catalyst that is used for purifying exhaust air according to embodiment 1.
Al with 100 weight portions
2O
3The CeO of powder, 80 weight portions
2-ZrO
2The water of the alumina sol of composite oxide power, 40 weight portions and 130 weight portions mixes.The solid content that it should be noted that alumina sol is 10 weight %.The mixture that grinds gained is with the preparation slurry.
Subsequently, prepare cellular matrix 1.Matrix 1 is made by cordierite, and diameter is 103mm, and length overall is 105mm, and hole density is 600 hole/inches
2From the downstream surface of matrix 1 95% of its length overall is immersed the described slurry.From slurry, take out matrix 1, and blow away excessive slurry from matrix 1.Then, with matrix 1 in 250 ℃ dry 2 hours down, and further 500 ℃ of calcinings 2 hours down, thereby form coating 2.Thus, only form coating 2 on the downstream area except that upstream region 10, described upstream region 10 extends to 5% of matrix 1 length overall from upstream end surface.With regard to 1L matrix 1, the formation amount of coating 2 is 200g.
Then, dinitro two ammino platinum (platinumdinitrodiammine) aqueous solution that will have a prescribed concentration are absorbed in the matrix 1 with scheduled volume coating 2.After the drying, matrix 1 was calcined 1 hour down in 500 ℃, loaded Pt thus thereon.In addition, the rhodium nitrate aqueous solution that will have a prescribed concentration is absorbed into matrix 1 with scheduled volume.After the drying, matrix 1 was calcined 1 hour down in 500 ℃, loaded Rh thus thereon.It is to be noted that with regard to the catalyst of a gained, the loadings of Pt and Rh is respectively 1.3g and 0.35g.In addition, do not form thereon in the upstream region 10 of coating 2 and do not load Pt and Rh.
Embodiment 2
Prepare the catalyst that is used for purifying exhaust air according to the embodiment of the invention 2 in the mode identical with embodiment 1, difference is that the length of the upstream region 10 that is provided with is 10% (being 10.5mm) of matrix 1 length overall.It is to be noted that with regard to the catalyst of a gained, the loadings of Pt and Rh is respectively 1.3g and 0.35g equally.
Embodiment 3
Prepare the catalyst that is used for purifying exhaust air according to the embodiment of the invention 3 in the mode identical with embodiment 1, difference is that the length of the upstream region 10 that is provided with is 20% (being 21.0mm) of matrix 1 length overall.It is to be noted that with regard to the catalyst of a gained, the loadings of Pt and Rh is respectively 1.3g and 0.35g equally.
Embodiment 4
Prepare the catalyst that is used for purifying exhaust air according to the embodiment of the invention 4 in the mode identical with embodiment 1, difference is that the length of the upstream region 10 that is provided with is 30% (being 31.5mm) of matrix 1 length overall.It is to be noted that with regard to the catalyst of a gained, the loadings of Pt and Rh is respectively 1.3g and 0.35g equally.
Embodiment 5
Prepare the catalyst that is used for purifying exhaust air according to the embodiment of the invention 5 in the mode identical with embodiment 1, difference is that the length of the upstream region 10 that is provided with is 50% (being 52.5mm) of matrix 1 length overall.It is to be noted that with regard to the catalyst of a gained, the loadings of Pt and Rh is respectively 1.3g and 0.35g equally.
The comparative example 1
Prepare the catalyst that is used for purifying exhaust air of the comparative example 1 according to the present invention in the mode identical with embodiment 1, difference is to form the coating 2 (being 105mm) that is filled with Pt and Rh on the whole length of matrix 1.It is to be noted that with regard to the catalyst of a gained, the loadings of Pt and Rh is respectively 1.3g and 0.35g equally.
Test and evaluation
To place respectively according to embodiment 1-5 and comparative example's 1 catalyst and be equipped with the exhaust system that discharge capacity is the petrolic block testing stand of 1.8L.Then, with Mn content be the described petrol engine of gasoline driven of 35mg/L.When changing air-fuel ratio A/F, drive described petrol engine.Show 400 ℃ of catalyst inlet temperature and 100,000hr at waste gas
-1Under the condition of air speed, detect each catalyst to HC, CO and NO
xConversion ratio.Detect the conversion ratio that obtains thus and be designated as initial conversion.
Then, on identical block testing stand, respectively the catalyst according to embodiment 1-5 and comparative example 1 is carried out durability experiment.In durability experiment, be the described petrol engine of gasoline driven of 35mg/L similarly with Mn content, but the waste gas that places its catalyst inlet temperature to be controlled at 900 ℃ catalyst continue 50 hours.Then, with detect HC, CO and NO
xThe identical mode of initial conversion, behind durability experiment, detect catalyst to HC, CO and NO
xConversion ratio.
The result who obtains is thus reduced curve map, and wherein A/F likens to and is transverse axis, and conversion ratio is as the longitudinal axis.In addition, as shown in Figure 2, determine the HC-NO of each catalyst among embodiment 1-5 and the comparative example 1 according to mode shown in Figure 2
xCross conversion rate and CO-NO
xCross conversion rate, A/F ratio-HC conversion rate curve and A/F ratio-NO
xThe intersection point of conversion rate curve and A/F ratio-CO conversion rate curve and A/F ratio-NO
xThe intersection point of conversion rate curve.All catalyst according to embodiment 1-5 and comparative example 1 all show at HC-NO
xCross conversion rate and CO-NO
xThe correlation that has height between crossing-over rate transforms.Correspondingly, select CO-NO
xThe cross conversion rate is as representing feature and reducing wherein CO-NO
xThe cross conversion rate is as the ratio of the longitudinal axis and the upstream region 10 relative matrix 1 length overalls curve map as transverse axis.Fig. 3 has illustrated this result.
As can be seen from Figure 3 the exhaust-gas purifying performance that catalyst showed of embodiment 1-4 is equal to or higher than the purifying property of comparative example 1 catalyst behind durability experiment, although the exhaust-gas purifying performance that comparative example 1 catalyst shows at first is the highest.Obviously this is because the upstream region 10 of the catalyst of embodiment 1-4 does not load due to Pt and the Rh.What can believe is that to have this advantage be because Pt that has suppressed to be caused by Mn and Rh poison for the catalyst of embodiment 1-4.
In addition, compare with comparative example 1 catalyst, the catalyst of embodiment 1-3 demonstrates improved exhaust-gas purifying performance behind durability experiment.Thereby the length that can obviously find out upstream region 10 particularly advantageously is in the scope of 5-20% of matrix 1 length overall.
Industrial usability
The present invention can be used for oxidation catalyst, three-way catalyst, NOx-selective-reducing catalyst and NOxAbsorption and reducing catalyst. In addition, it can also be used for filter catalyst. For example, contain The filter catalyst of diesel particulate materials filter (being DPF), described diesel particulate materials The hole path of filter is alternately blocked in end opposite, and wherein forms in the hole of DPF hole wall Be filled with the coating of catalyst component.
Fully describing in the situation of the present invention, those of ordinary skills can obviously find out Can be at the bar that does not depart from the subject or scope of the present invention that comprise appended claims described here Carry out multiple change and conversion scheme under the part.
Claims (7)
1. catalyst that is used for purifying exhaust air, it contains:
The matrix that comprises exhaust steam passage;
The coating that on described exhaust steam passage, forms; With
Fill in the catalyst component on the described coating,
Wherein the loading density of catalyst component is greater than the loading density of catalyst component in the upstream region in the downstream area, and upstream region determines that by the predetermined length that starts from the matrix upstream extremity zone on the exhaust steam passage direction except upstream region is a downstream area.
2. according to the catalyst described in the claim 1, wherein upstream region does not contain the catalyst component of described filling.
3. according to the catalyst described in the claim 2, wherein do not contain described coating in the upstream region.
4. according to the catalyst of claim 1-3 described in each, the wherein said predetermined length of upstream extremity that starts from is less than 30% of matrix length overall.
5. according to the catalyst described in the claim 4, the wherein said predetermined length that starts from upstream extremity is in the scope of 5-20% of matrix length overall.
6. according to the catalyst of claim 1-3 described in each, the wherein said predetermined length of upstream extremity that starts from is less than 31.5mm.
7. according to the catalyst described in the claim 6, the wherein said predetermined length that starts from upstream extremity is in the scope of 5-21mm.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003370983A JP2005131551A (en) | 2003-10-30 | 2003-10-30 | Catalyst for purifying exhaust gas |
| JP370983/2003 | 2003-10-30 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1623635A CN1623635A (en) | 2005-06-08 |
| CN1311893C true CN1311893C (en) | 2007-04-25 |
Family
ID=34510405
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2004100871297A Expired - Fee Related CN1311893C (en) | 2003-10-30 | 2004-11-01 | Catalyst for purifying exhaust gases |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP2005131551A (en) |
| CN (1) | CN1311893C (en) |
| CA (1) | CA2485893C (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4736724B2 (en) * | 2005-11-09 | 2011-07-27 | トヨタ自動車株式会社 | Exhaust gas purification device for internal combustion engine |
| WO2008126330A1 (en) | 2007-03-30 | 2008-10-23 | Ibiden Co., Ltd. | Honeycomb structure |
| US20140227156A1 (en) * | 2011-10-06 | 2014-08-14 | Mack Trucks Inc. | Diesel oxidation catalyst and method of treating engine exhaust gas |
| JP5720949B2 (en) * | 2011-12-08 | 2015-05-20 | トヨタ自動車株式会社 | Exhaust gas purification catalyst |
| JP5757297B2 (en) | 2013-01-23 | 2015-07-29 | トヨタ自動車株式会社 | Catalytic converter |
| JP5780247B2 (en) | 2013-01-23 | 2015-09-16 | トヨタ自動車株式会社 | Catalytic converter |
| JP5821887B2 (en) | 2013-04-03 | 2015-11-24 | トヨタ自動車株式会社 | Catalytic converter |
| JP7035780B2 (en) * | 2018-05-08 | 2022-03-15 | トヨタ自動車株式会社 | Catalyst structure |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5846502A (en) * | 1996-01-16 | 1998-12-08 | Ford Global Technologies, Inc. | Mini-cascade catalyst system |
| TW475027B (en) * | 2000-06-02 | 2002-02-01 | Emitec Emissionstechnologie | Catalyst carrier body with protective zone |
| CN1411394A (en) * | 1998-04-28 | 2003-04-16 | 恩格尔哈德公司 | Monolithic catalysts and related process for mfg. |
| EP1342499A1 (en) * | 2002-03-07 | 2003-09-10 | Delphi Technologies, Inc. | Multizone catalytic converter |
-
2003
- 2003-10-30 JP JP2003370983A patent/JP2005131551A/en active Pending
-
2004
- 2004-10-25 CA CA 2485893 patent/CA2485893C/en not_active Expired - Fee Related
- 2004-11-01 CN CNB2004100871297A patent/CN1311893C/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5846502A (en) * | 1996-01-16 | 1998-12-08 | Ford Global Technologies, Inc. | Mini-cascade catalyst system |
| CN1411394A (en) * | 1998-04-28 | 2003-04-16 | 恩格尔哈德公司 | Monolithic catalysts and related process for mfg. |
| TW475027B (en) * | 2000-06-02 | 2002-02-01 | Emitec Emissionstechnologie | Catalyst carrier body with protective zone |
| EP1342499A1 (en) * | 2002-03-07 | 2003-09-10 | Delphi Technologies, Inc. | Multizone catalytic converter |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2485893A1 (en) | 2005-04-30 |
| CN1623635A (en) | 2005-06-08 |
| JP2005131551A (en) | 2005-05-26 |
| CA2485893C (en) | 2010-07-27 |
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