DE2341736A1 - CATALYTIC PROCEDURE - Google Patents

Description

PATENTANW vLTSBÜRO TlEDTKE - ΒϋΓ -ING - KlNNE

TFL. (0Λ11) Γ.316Γι3 ^Γ .6 TFlEX: 5P4845 tlpat VIUE ADDRESS- Gnrmaniapatnnt Munich

8000 Munich 2 Bavariaring4 | 1 Aug. 7, 1973

P.O. Box 202403

ICI Case No. B 25381/25502 / 25633/26027

Imperial Chemical Industries Limited, London S.W. 1, UK

Catalytic process

The invention relates to a catalytic process. The invention particularly relates to a method of treating Exhaust gases from internal combustion engines, a catalyst for the process, a carrier for the catalyst and a process for the production of the support and the catalyst. When speaking of internal combustion engines in the present application should also be understood to include internal combustion engines, internal combustion engines and explosion engines.

It has already been proposed to exhaust gases from internal combustion engines to treat with or via catalysts that contain metals or their compounds and refractory oxides, to decompose the oxides of nitrogen and / or carbon monoxide and To oxidize hydrocarbons. Many such treatment methods are satisfactory as long as the catalyst is fresh

409812/0834

is. If the catalyst is used, however, for some time these procedures are less effective. A main reason for the loss of catalytic effectiveness is the conversion of the base metal oxides with the refractory oxides, whereby inactive compounds are formed. This happens even under obviously pure reducing conditions in which base metal oxides should not be present. Possibly the reaction occurs at times when the gas mixture composition fluctuates to the pure oxidizing conditions or passes over, or it finds, due to the oxygen present, together with carbon monoxide, hydrogen and hydrocarbons in the exhaust gases freshly emitted from the internal combustion engine. Apparently the free metal is oxidized by steam or carbon dioxide and bound irreversibly. However, this is not a complete one Explanation, as catalysts, the precious metals without base metals also lose their activity during use.

It has been found that the loss of catalytic activity can be reduced if acidic and amphoteric Combines or combines refractory oxides of the catalyst carrier with an added basic oxide. Under the expression "Refractory oxides" are generally intended to be difficult to melt and tough Oxides are understood. Catalysts on such supports are only very effective in removing nitrogen oxides slightly reducing conditions or even under moderately oxidizing conditions suitably active in contrast to many previously proposed catalysts

4098 1 2/0834

Sators that only work under completely pure reducing conditions are active. They are also effective in oxidizing carbon monoxide and hydrocarbons.

The invention also relates to a catalyst support which contains a primary catalyst support which in turn contains a secondary catalyst support, and wherein the secondary support comprises essentially 1 or more non-volatile acidic and / or amphoteric oxides essentially combined with one or more basic oxides of the Contains groups II, III or IV of the periodic table.

The term "primary support" means the material of which the catalyst is in terms of its mechanical Shape and structure depends. The term "secondary support" means the material with which the catalytically active material is made is closely associated. The term "essentially combined" means catalysts in which the free acid or amphoteric oxide is present, but is not accessible or available for the active material or in a small amount, based on the active material, "is present, so that after any additional acidic oxide has reacted with the active material, sufficient excess active material for the catalyst remains so that it is still sufficiently active. In general, it is preferred that at least 70 percent by weight of the acidic or amphoteric oxide with basic Oxides are combined.

40981 2 / 083A

ORIGINAL ^ iPSCnTD

In the present application, the compositions of solids expressed as percentages by weight based on non-volatile material present. The composition of gases is given in percent by volume, unless otherwise stated. The periodic table is in "Abridgments of Specifications" published by the UK Patent Office can be found.

The acidic or amphoteric oxides of the secondary carrier can be, for example, aluminum oxide, silicon dioxide or use other silicon oxides, chromium oxide, manganese oxide or iron oxide or mixtures or compounds thereof. These oxides and in particular aluminum oxide and chromium oxide, if they were present in the free state in a catalyst, react with the oxides of nickel, cobalt or copper, forming spinels that are difficult to reduce are. If more than one acidic or amphoteric oxide is present, the combination results in a complicated mixture of oxides, especially when silica is one of the acidic oxides. Aluminosilicates are popular because of the stability of their compounds preferred with the basic oxides. Even if the acidic oxide is only weakly acidic, such as titanium dioxide or zirconium oxide, the combination with the basic oxide can be advantageous.

The basic oxide used for the second carrier is preferably an oxide of a metal of a Α group of the periodic Systems, in particular of the Ha group, in particular of Calcium, strontium or barium, or more than one of these

409812/0834

Metals. The most suitable is calcium. Such oxides appear to be of general use. Other basic oxides can only be used with certain acidic oxides. For example, zirconium oxide is more basic than silicon dioxide, and it has been found that zirconium silicate is inert to nickel oxide even at 1350 ° C. Zinc oxide can also be combined present with aluminum oxide. Certain rare earth oxides are basic components of the combined oxide suitable. It is possible to oxide some of a non-noble catalytic To have metal combined with acid and / or amphoteric oxide in the secondary carrier. For economic However, this is generally avoided for reasons.

The secondary carrier can be an added naturally occurring mineral or a separately produced mineral, or it can be the in situ reaction product of precursors, or, if the primary carrier contains acidic and / or amphoteric oxides, the in situ formed reaction product from the added oxide will be with the primary carrier. Among the combined oxides that can be used are melitite (particularly gehlenite Ca ₂ AIpSiO ₇ because of its high melting point and inertness and, less preferred, the isomorphic compounds of intermediates to akermanite Ca ₂ MgSi ₂ O ₇ and the higher melting types of Iron melitite), anorthite (CaO.Al ₂ O ₃ .2SiO ₂ ), calcium silicates (such as rankinite, pseudowollastonite and wollastonite CaCSiO ₂ and also calcium orthosilicates CaMSiO ^, such as monticellite, where M means, for example, manganese, iron or cobalt) and

409812/0834

Calcium aluminates (especially those that contain at least one molecule of CaO per molecule of AIpCU). It appears advantageous to use combined oxides in which the basic oxide is present in an amount which forms a stoichiometric compound with the acidic or amphoteric oxide when viewed as a monomeric acid. For example, CaO.Al ₂ O is preferred over CaO.2Al ₂ O. Cordierite Mg ₂ AlASIj-O ₁₈ is less suitable as a secondary carrier, which is used at high temperatures, since it reacts relatively easily with the nickel oxide.

If the basic oxide is unstable in vapor, like calcium oxide, it should be in a dead burned state, when it is present in a considerable excess in the free state is . Other oxides, such as those commonly used as catalyst supports, can be present in the secondary support be present and thus in a catalyst made therefrom associated with the active materials. In general however, it is found that the combined oxides do not require any such modification.

The porosity of the secondary support, being voids between fibers or particles or the open volume of Multi-tube matrices are excluded, is suitably in the range of 30 to 70% by volume or is larger. Its specific gravity is suitably 0.5 to 1.5,

and its specific surface area is 0.01 to 250 m / g. A method of making secondary supports and so-

40981 2/0834

with high porosity catalysts is described below. .,. ■ · ■■

The primary support can be in any suitable mechanical form, for example in the form of discrete particles (especially as rounded granules), in the form of fibers or as bedrock or matrix with many tubes or as coating on any of these shapes or on a metal substrate such as wire, a reaction vessel wall or a perforated structure or a mesh. The primary support preferably consists of a refractory, non-metallic, in particular oxidic material and can, for example, by casting, deforming, deforming under pressure, Extrusion, by wet granulation or spray crystallization in air or oil. If the primary Carrier is a multi-tube matrix, it can be formed by molding, extruding, coating a convertible molding, such as aluminum foil or an impermanent molding such as paper or cloth, or it can be made in simpler ones Molds are made. If the primary carrier is fibrous, it can be spun and or in various ways Blow molding are made and then you can felt, weave or make paper or self-supporting Connect units. Alternatively, the primary support itself can be a metal substrate as described.

When the primary support is a multi-tube matrix, the cross-sectional shapes of the passages in the support can

40981 2/08 34

for example triangles, squares, hexagons or figures formed by a wavy line and a straight line or a flat curve are limited to be. The number of passes

ρ ρ

per 6.45 cm (1 inch) is suitably in excess of 25 and can can be as high as 200 to 600, although 40-500 appears to be the most appropriate range. The walls between the passages are typically 0.1 to 0.4 mm thick.

When the secondary support is the reaction product of a basic oxide with the surface of the primary support, the concentration of the alkaline earth metal oxide, free and bound, is suitably 0.5 to 25 %, especially 2.5 to 15 % f calculated as CaO equivalent. If the primary support is in a form with a geometrical surface area larger than that of the particles (in the case of a matrix with multiple tubes or in the case of fibers), the proportion of alkaline earth metal oxide should match the geometrical surface area. The concentration of alkaline earth metal (calculated as CaO equivalent and including the free and bound oxide) is suitably in the range from 0.2 to 10, in particular

at 1 to 6 milligrams per cm of geometric surface. Such values correspond to the above percentages by weight if the geo-

p -χ

metric area is -32 cm / cm.

When the secondary support has been applied as such or when it is the reaction product of precursors with the surface of the primary carrier, the ratio of secondary to primary carrier should suitably be in the range of

409812/0834

2TaLs 40 percent by weight, especially 5-25 percent by weight, lie.

The primary carrier suitably contains an oxide such as magnesium oxide, aluminum oxide, silicon oxide, titanium dioxide, Zirconium oxide, hafnium oxide, thorium oxide, chromium oxide and mixtures or compounds of these with one another or with basic ones refractory oxides, such as oxides of calcium, strontium or barium, in highly refractory forms, such as molten Magnesium oxide, highly calcined aluminum oxide, calcined aluminum silicate, zircon mullite, spinels and hydraulic Cements.

Carriers with specific surface areas in the range from 0.1 to 100 m / g, such as aluminum oxide, calcined at 950 1500 ° C, alpha-aluminum oxide bound with bentonite and suitably calcined kaolin / cement mixtures are particularly suitable.

Although it is generally preferred to use a primary support material that is the best possible thermal and mechanical resistance, the present invention includes supports and catalysts that are operational Simplicity the same material as calcium aluminosilicate for both the primary and secondary supports and indeed some do not contain a secondary carrier introduced as a separate component or at some the primary support itself contains catalytically active material. (compare example 5). It is under-

409812/0834

" ¹⁰ " 2341738

shows that it is correct to speak of the primary and secondary carrier in the case of such catalysts, since the kata-r lytic chemical reaction evidently mainly in the Surface area of the catalyst less than about 30 Takes place micron deep so that the inner regions of the catalyst act only as the primary support.

Gehlenite and thus isomorphic compounds are particularly suitable when the same compound is both primary as well as acting as a secondary carrier.

As examples of primary carriers consisting of a combination of acidic or amphoteric and basic oxides, one can mention cyclosilicates, such as cordierite, which has the empirical formula MgpAl ^ Si ^ O ^ g, where possibly some or all of the magnesium can be replaced by iron and / or manganese. In these connections can every magnesium or iron or manganese atom can be counted for two aluminum atoms, as in the compound MgAlpO ^, and thus the silica is not neutralized at all. In the same way, any magnesium or iron or Manganese atoms are calculated for each silicon atom, so that three silicon atoms and four aluminum atoms are not taken into account

are. Presumably no explanation explains the actual chemical situation, and in any case contains synthetically formed Cordierite often has other compounds. As a result, however, there is good adhesion of the secondary support, namely the calcium aluminosilicate, and the cordierite structure

409612/0834

is protected from attack by oxides such as nickel oxide. Other suitable primary carrier materials uro-barreled petalite » Silicon nitride and silicon oxynitride.

If the primary support is a matrix made of bonded refractory fibers, it may be in some form, for example, as a set of refractory paper sheets on a suitable block or frame as a support or a fiber block with sufficient permeability for the gas to pass through, or he can have passages. The fibers can be made of any material having suitable mechanical properties, for example aluminum oxide, silicon oxide, aluminum silicate, glass wool, chromium oxide, titanium oxide or zirconium oxide. Fibers consisting essentially of alumina and / or zirconia and less than 10 microns in thickness and essentially free of particles known as "pearl barley" are particularly suitable. These fibers are prepared by containing a viscous composition ^1, an aqueous solution of an aluminum salt and / or zirconium salt and a water soluble organic polymers processed into fibers, drying the fiber formed and heated to the salts to decompose to the oxides and to degrade the polymer as described in commonly assigned British patent applications 29909/70 and 4369/71, published as Dutch application 7108399. The resilient bond of the fibers can be achieved, for example, by any of the compounds contained in the fibers.

40981 2/0834

2341735

and these can be in the form of! colloidal solutions, aqueous solutions of thermally decomposable compounds or organically thermally decomposable compounds be applied.

The invention also relates to processes for the production of catalyst supports. In one proceeding a suspension of finely divided secondary carrier material is made in a liquid, and then the suspension is applied to the surface of the primary support. The suspension can contain additives such as soluble polymers or contain surfactants to improve their stability and temporary adhesion. In general, can adhesion through a subsequent heat treatment at, for example, at least 800.degree. C., in particular at 900 to 1200.degree be improved. These temperatures apply in particular to calcium aluminosilicate systems. Suitable temperatures for other systems can of course be established experimentally.

In a second method, a solution or suspension of precursors for the secondary carrier, i.e. compounds which react with one another to form the secondary carrier. Heat treatment is desirably carried out, to cause the conversion and to give an adhesion or adhesion.

409812/0834

Catalytic materials may suitably be present in the material applied to the primary support be.

In a third method, a primary carrier is selected which contains at least one of the oxides associated with connected to the secondary carrier. Then the other oxides that will be attached to it are applied, and the reaction is carried out "to form the secondary support on the surface of the primary support. A heat treatment is desirable as in the case of the second method. The primary carrier preferably contains acidic and / or amphoteric oxides, and a basic oxide is applied to them.

When the oxide applied is an alkaline earth oxide, the primary support is conveniently impregnated with the nitrate. Other suitable decomposable salts, such as the nitrites, bicarbonates, carboxylates (such as formates, acetates or citrates) can also be used. Hydroxides are also suitable and also silicates, aluminates and aluminosilicates, provided that they are uniformly dispersed to compensate for their low solubility. Insoluble compounds can be used as a slurry alone or together with soluble compounds. Hydrolyzable compounds, like the halides, can be used but have the disadvantage that steam treatment is required is to oxides under easily feasible conditions

409812/0834

234173

to build. Any suitable method can be used, for example a dipping or spraying, use, to apply the secondary support material or precursors thereof to the primary Apply carrier.

After the alkaline earth compound has been applied, is suitably for example at 120 ° C, before Calcination dried. The calcination is preferably carried out at a temperature in the range from 600 to 1400 ° C., in particular at 800 to 1200 ° C, so that you get an oxide layer and / or a combination or compound with the primary carrier causes.

In all of these three procedures, a primary carrier is which has the desired shape is used as the starting material. A fourth method, however, uses a calcium aluminosilicate or precursors thereof formed in the desired shape. As stated earlier, there is the secondary carrier from the surface layers of your such form. In this method, the catalytic material can be present in the material prior to deformation. This method has the advantage that a catalyst is formed in a single operation.

If a precursor is used for the catalytic material and this precursor can be combined with the precursors for the secondary Carriers react, so it is preferably reduced before the heat treatment.

ORIGINAL INS PcCTED 409812/0834

Whichever method is used, it is preferred to heat treatment at a temperature above 800 ° C, in particular at 1000 to 1600 ° C to be carried out. Preferred it is carried out in the presence of steam, because it causes the reactions that cause adhesion, or at which the secondary carrier is formed, are accelerated. The heat treatment can be carried out in more than one stage will. For example, the support can be moderately calcined, for example up to 600 ° C, or it can be just plain The remaining heat treatment can be carried out by the user of the carrier. The latter Method is suitable when catalytic material is present, as in Methods 1, 2 and 4 above.

If desired, the methods can also be combined.

The secondary support is preferably formed in the presence of a compound which is thermally decomposable, wherein a highly porous solid is formed, but preferably essentially up to 600.degree. C., in particular up to 1100.degree is stable. This increases the porosity of the secondary carrier. This catalyst is different from the one one obtains when using constituents which are decomposable at lower temperatures. Organic materials and graphite decompose or burn before a combination between the basic oxide and the acidic or amphoteric oxide has taken place to a significant extent.

409812/0834

A very suitable thermally decomposable compound is calcium carbonate, which is remarkable in air Speed only decomposes above 740 C. Other compounds like the carbonates of magnesium, strontium and Barium have a comparable stability.

It is within the scope of the present invention to carry out the heating step in the presence of an atmosphere which contains more carbon dioxide than the air to raise the decomposition temperature. The decomposable compound is particularly suitable as a source for the basic oxide. Porosity increases can also be achieved through the use of hydrated (= water-containing) oxides can be achieved.

In processes 2 and 4 and in the combination process, the reaction products can already be used as starting materials of basic and acidic or amphoteric oxides. For example, calcium carbonate, calcium silicate CaSiO, and anorthite CaAlpSipOg can be converted to gehlenite to manufacture.

If method 4 is used, different deformation methods can be used, which have already been mentioned in the description the support structure were mentioned. If the form is a multi-tube matrix would like to have, a preferred method is to make a plastic composition, which is the compound that is decomposable to the highly porous solid, the combined oxides or mixtures of Oxides or of compounds that are decomposable or therewith

409812/0834

ORiGINAL Μ ***}

react, a liquid and a compound that the Viscosity regulated and soluble or swellable in the liquid contains. Then this mass is sequentially by a zone containing a plurality of discrete primary channels within a solid block and by a Driven unification zone that contains secondary channels within the same block, with the secondary Channels are closely connected and the total cross-section of the secondary channels is equal to or sufficiently less than that of the primary channels and wherein the transit time through the secondary channels is long enough to allow a union of the feed material to give a matrix. The extrudate thus formed is then dried and heated to obtain the combined oxides. One such method is detailed in the UK patent application 13721/71 by the same applicant as that published Dutch patent application 7206153.

In this process, the heating should be sufficient to bring the extrudate to a state in which it can be handled. It can then be further heated by the consumer or user of the catalyst, to complete the formation of the combined oxides, or to create ceramic bonds, or both Achieve goals. Catalytic material and / or material that can be transferred into it can be in the extruded feed

4093 1 2/0834

234173S

composition may be present or added later.

The compound, which is decomposable to a highly porous solid, can be any of the basic, acidic or be amphoteric oxides.

If the oxides are heated by the catalyst manufacturer, it is preferably done at 1000 to 1600 ° C. A suitable time is in the range of 2 to 40 hours.

The invention also relates to a particular method of making the carrier, and this is particular in the method 2 and 4 applicable, in which the heat treatment is carried out with a gas stream and where a exothermic oxidation reaction takes place.

Any gas flow can be used as the gas flow, which gives the desired temperature, which is preferably 800 to 1600 ° C. It preferably contains an oxidizable compound, which does not form undesirable by-products, for example one can use hydrogen, carbon monoxide and mixtures use of it. Hydrocarbon vapors can be used under conditions where carbon is formed can be avoided, for example by limiting its volumetric concentration in the gas.

A very suitable gas is one obtained by incomplete combustion of a hydrocarbon fuel with air. That from an internal combustion engine with

409812/0834

rich mixture is operated, outflowing material, which preferably contains 3 to 8% by volume of carbon monoxide, is after Adding air is a suitable gas for this use. Such a gas usually contains free hydrogen in an amount of 1 to 3% by volume.

The heat treatment can take place before or after the incorporation of the catalytic material. It is preferably done after the addition, as a certain catalytic oxidation then takes place.

The invention relates to a tempering process for a catalytic process for exhaust gas treatment,

adjusting the fuel injection into the engine or the gasification system to produce an exhaust gas obtained that contains 3-8% by volume of carbon monoxide and one Introduces air into the gas to oxidize the carbon monoxide and heat the gas to a temperature above 800 C. Afterward the resulting mixture is reacted in the presence of a catalyst, the catalyst at the beginning is in the light calcined or incompletely heat-treated state until substantial formation the compounds of basic and acidic and / or amphoteric components of the catalyst has taken place. If the process is used to decompose nitrogen oxides reductively, the air supply is then switched off and the engine or the prime mover is set back to normal operating conditions, whereby an exhaust gas is obtained,

409812/0834

that contains up to 2% by volume of carbon monoxide.

Such a method can be used well by petrol stations or drivers, especially in motor vehicles, which are already equipped with devices to remove the NO removal catalyst bed warm up under oxidizing conditions.

The process can be carried out with mixtures of the ingredients before or after the formation process. Preferred it is carried out according to the deformation process so that the shapes are as homogeneous and mechanically strong as possible getting produced.

The invention relates to a catalyst in which the support is one or more catalytically active materials contains.

In one type of catalyst according to the invention, one or more metals is used as the active material Platinum group used.

If the catalyst is used to oxidize exhaust gas, the platinum group metal is preferably used as platinum or palladium, especially palladium. If it is used for the reduction, it is preferred to use it as the metal a combination of platinum or palladium with rhodium. Other metals suitable for reduction are ruthenium, Iridium and their mixtures. The concentration of metal of the platinum group is oxidative and reductive

409812/0834

2341738

Treatment suitably in the range from 0.001 to 5% by weight, especially in the range from 0.005 to. 0.5% by weight, calculated as equivalent (i.e. equiatomic) palladium metal, based on the components of the catalyst, that are non-volatile at 900 ° C, or more if calculated based on the secondary carrier. If the carrier has a geometric area of 32 cm / cm these weight percentages result in 0.0004 to 2.0

and 0.0002 to 0.2 mg per cm of metal. Such a geometric Area can be obtained when the catalytic support has a multi-tube matrix.

If in the present application of multiple tubes— or multi-tube matrix is spoken of, becomes a matrix understood by this, which is known by the Anglo-Saxon term "multi-tubular matrix".

In another type of catalyst according to the invention, the active material contains metallic nickel or Cobalt or an alloy of these metals and possibly small amounts of copper or silver or a metal of the Platinum group or of more of the metals mentioned. The nickel or cobalt or nickel / cobalt alloy content of the Catalyst is suitably in the range of 2 to 50% by weight calculated as mono-oxides. The content of the total monoxide and secondary carrier is suitably in the range of 5-95%. When copper in the monoxides is present, its amount is calculated as CuO

409812/0834 original inspected

preferably 2-10%, based on the monoxide, and if a metal of the platinum group is present, its amount is preferably 0.001 to 1.0% or correspondingly more, based on the total amount of monoxide and secondary carrier. Such catalysts are suitable for pure reduction or incomplete oxidation treatments of exhaust gases. If an oxidation treatment is to be carried out, one of the oxides of the above base metals and / or one or more oxides of copper, manganese or chromium or, less preferably, of other non-noble transition metals can be used as the active material. The concentration of such oxides is suitably the same as in the reductive catalysts and the same content of platinum group metals can be used. (In such catalysts the manganese content is calculated as MnO and the chromium content as Cr ^ O ^, their lowest oxides).

The catalyst can be prepared, for example, when you combine the primary and secondary supports with a solution of a compound that contributes to the catalytically active Material is thermally decomposable, impregnated, heated to bring about the thermal decomposition and optionally that Product of such decomposition is reduced to the metal when the active material is a base metal or an oxide is. In this case, the catalytic material should preferably be limited to the secondary carrier as much as possible and the impregnation conditions should be chosen accordingly, for example by adding the

409812/0834

- 13 -

Regulated or adjusted volume of the impregnation solution. Will impregnated with a compound of a platinum group metal, a salt or an ionic or nonionic complex can be used. Complexes such as those with amines are suitable because of their resistance to hydrolysis. The impregnation can be combined with the treatment with an organic Acid or together with an insolubilization step such as a reduction reaction or sulfidation reaction can be carried out.

In another method, the catalytic material and / or precursors thereof and a secondary one Carrier material and / or the precursors thereof mixed and applied to the secondary carrier and the product is heated and reduced if necessary.

Any suitable method such as immersion can be used in the above impregnation or application or spray, use.

In the third method, as described in the previous paragraph, a mixture is introduced into the catalyst form deformed and heated in a suitable manner and, if necessary, reduced. The product of this process has as above erüärt, some catalytic material in its inner areas. Preference is given to this and the preceding ones Process the precursors for the catalytic material before Heating reduces when they are compounds of base metals, such as nickel. Such connections are preferred

12/0834 Qfkuhal inspects.

tend to be in relatively inactive form, such as introduced as oxides with a particle diameter greater than one micron.

The heating temperatures used are those as described in connection with the production of the carrier, if the method comprises forming the secondary support or adhering to the primary support. About catalyst precursors to heat, a temperature in the range of up to 800 ° C is suitable.

A reduction is required when the catalyst is used for the reductive treatment of exhaust gases. she but is usually not carried out by the catalyst manufacturer, since it takes place in contact with the exhaust gases. A reduction to which reoxidation occurs can be used when using an oxidation catalyst manufactures.

The product (catalyst precursor) which is ready to be filled into reductive exhaust gas reactors, which but still to be reduced in this is the usual article of commerce.

The invention also relates to a treatment method for exhaust gases in which a catalytic converter is used. This treatment method can be reductive to nitrogen oxides or it can be oxidative to remove carbon monoxides and hydrocarbons. On a reductive stage can be an addition of air and an oxidative stage

409812/0834 ORK "- -" ^PECTED

Follow level. In some cases, depending on the engine type and local emission standards, it is possible to use a single catalyst, preferably the one herein described type, to use, which contains one or more metals of the platinum group, to the nitrogen oxides, To remove carbon monoxide and hydrocarbons from an exhaust gas at the same time, possibly as a result of. continuous addition of air contains approximately equal amounts of reactive and oxidative components. If ■ nitrogen oxides are removed by a process the exhaust gas is preferably passed over a pre-oxidation layer to remove residual oxygen. The method of NO reduction is preferred in the presence of added air started until the catalyst has reached operating temperature.

When the method of the present invention is used to remove oxides of nitrogen, the reducing power is the Gases by the function

CO + H ₂ - 2O ₂

is expressed in which "CO", "H ₂ " and "O ₂ " are expressed in percent by volume, preferably positive. However, a reducing force larger than 8 corresponds to poor fuel economy. CO is above 2 % and O ₂ is below 0.3 %. The carbon monoxide content of the gas does not generally have to be more than 2 % , and engines that are so constructed that have a stoichiometric or somewhat "lean"

409812/0834

- ■ 26 -

2341735

Fuel mixture is used, can by the invention Processes are brought into such a state that they do not pollute the environment. The inventive The process also enables effective removal of the oxides of nitrogen in systems to air as a common measure or to warm up. The best use is made of nickel-copper catalysts and similar catalysts of base metals when the reducing power is in the range from 0.5 to 6.0. If a platinum group metal is present, the reducing power may be lower, even down to approximate equivalence.

The process temperature is usually, regardless of whether the process works reductive or neutral, above 300 ° C. and preferably above 500 ° C. It is preferred above 600 ° C, for example at 650-850 ° C if the catalyst does not contain any platinum group metal, but at 500-700 ° C when a platinum group metal is present. These temperatures refer to continuous operation and do not apply when starting or with strong accelerations and they correspond to the "stabilized way" of the Experiment as described in United States Federal Register 36, No. 128, July 2, 1971. When heating with air or in the case of rapid acceleration, the temperature can rise by 150 - 200 C above the value in continuous operation.

When the exhaust gas treatment process is an oxidation process, it is suitably used at temperatures in the range

409812/0834

from 200 - 1000 ° C. If it is carried out for the complete oxidation of the exhaust gases, the temperature typically increases to 400-850 ⁰ C and rises in the direction of the gas flow due to the heat of reaction, regardless of whether these gases obtain a single catalytic treatment or whether oxidation after removal of the Nitrogen oxides takes place under pure reaction conditions. To this end, the supply of oxygen (usually air) should be sufficient to oxidize all of the carbon monoxide and hydrocarbons present, and a moderate excess, for example up to 2 % v / v. should be present. However, one can also use a deficit of oxygen for incomplete oxidation and work at a lower temperature. An example of such a use consists in the preliminary oxygen removal from a purely reducing exhaust gas as a pretreatment for the treatment over a catalyst to remove the nitrogen oxides, as described in German Offenlegungsschrift 2,222,467, which corresponds to British application 13 722/71, of the same Applicant is described.

The space velocity of the process depends on the shape of the catalyst. It is typically (with grainy or matrix catalysts) in the range from 0.10 to 3 »0 χ hours for the separate reduction or oxidation or for the combined reduction and oxidation and it is two to five times this range for an oxidation that performed prior to nitric oxide removal, if

409812/0834

such a layer is used. If a vehicle is propelled by the internal combustion engines, the space velocity is similarly in the range between the lower and upper values, which differ by a factor as large as 10, more likely up to 6.0, based on starting conditions which the speed of rotation of the engine is compensated by changing gears. The catalyst volume should be suitable for the very high gas flows during acceleration when starting off in city traffic. The definition for the space velocity is intended to mean a range SV., To SVp, where SVp means six to ten times SV ₁ within the specified broad range. Such space velocities correspond to catalyst volumes which can be used in automobiles, for example 0.5 to 5.0 liters according to the engine size and the characteristics of the engines.

The invention also relates to a reactor which contains the catalyst and has an inlet opening which is suitable for connection to an engine and which has an exhaust port. The subject of the invention are also internal combustion engines that contain one or more such reactors in the exhaust pipes.

The gasoline feed (or engine feed) for the engine suitably has a sulfur content less than 200 ppm w / w. (as S) and less than 0.4 grams of lead (as Pb) per 3.8 liters (per US gallon), preferably less than 0.01 grams. The phosphorus content

409812/0834

"-1 -

in the motor gasoline can go up to 500 ppm. without noticeable disadvantages, if one correctly selected kata-, lytically active materials used.

The following examples include an assay method according to US Federal Method (II) and Laboratory search procedures, some with an engine, under conditions found to be related to it stand. The Federal process can be summarized as follows. Starting with a cold start the exhaust gases from the first 505 seconds are collected in bag A. and then the gases in the subsequent operation, the referred to as "stabilized mode", collected in bag B (total time 1369 seconds). The first 505 seconds include two strong accelerations and the stabilized state a sequence of standstills (without engine shutdown) and moderate speed operation. This is followed by 10 minutes of standstill, whereby stop the engine and repeat the first 505 seconds, collecting the exhaust gases in bag C. The emission values of each bag are calculated in grams and added together according to the formula (0.43A + B + 0.57C) * / «7» 5, where 7.5 is the number of miles driven in the attempt. The allowed limits in example 11 are those originally set for 1976. It should be noted, however, that less strict limits may be set in the near future.

409812/0834

If the catalyst activity is given as a first order rate constant k or k »r see”, so it becomes according to the formula

k or k _M = 2.3 SV - ^ b ₁₀

"Z 3600 '" 1 - 0.01C

calculated where SV is the volume hourly space velocity and
C represents the percentage conversion of NO to Np.

The catalysts of the invention have a high

Activity and stability. So far, satisfactory NC ^ distance has been achieved in attempts to travel 43,450 km or 27,000 miles.

example 1

Palladium-Gehlenite-Aluminum Oxide Catalysts

Four catalysts, which contained palladium and which contained an extruded matrix or extruded cylinder as the primary carrier, were made of aluminum oxide, which was bound to bentonite, of the composition 95 % AlpO ,, 5 %

SiOp and with a specific surface area of 0.3 m / g accordingly manufactured using the following process:

A. A 2.54 cm (1 inch) square matrix block with an apparent density of 1.1 to 1.4 and with 512 passages per

2 2 ^ 5

6.45 cm (square inch) (area 32 cm / cm) was added to a to apply second carrier, in a saturated calcium nitrate solution immersed, then the solution was allowed to drain, he

409812/0834

heated at 1000 ° C for k hours, and then this procedure was repeated. The CaO content of the block was 8% by weight, which corresponds to 3.25 mg / cm of geometric surface. Material (secondary support) was scraped from the surface and examined by X-ray diffraction spectrum. The predominantly calcium-containing phase was found to contain gehlenite. The coated block was immersed in a 0.8% solution of palladium nitrate containing 0.2 ml of 60% nitric acid per 100 ml of solution, then the solution was allowed to drain off and dried.

B. A similar block was immersed in a suspension of colloidal milled alumina then left the solution drained, dried at 120 C and heated at 650 ° C for four hours. This procedure was repeated. The coated block, which contained alumina as a secondary support, was washed with a 3.2% aqueous solution from palladium nitrate, the 0.2 ml of 60% nitric acid per Containing 100 ml of solution, impregnated, then the solution was allowed to drain and dried.

C. To make a catalyst that does not have a secondary Containing carrier, a similar block was immersed uncoated in a 0.16% solution of palladium nitrate, which Contained 0.2 ml of 60/6 nitric acid per 100 ml of solution. Man drained the solution and reduced with dilute hydrazine solution. The hydrazine solution was drained, then was rinsed and dried.

40981 £ 2/083

D. Extruded cylinders of the same material as the matrix blocks were coated twice with calcium oxide using the procedure described for Catalyst A. It was then calcined at 1050 ° C. and impregnated with a 0.42% palladium nitrate solution containing 0.2 ml of 60% ± ge nitric acid per 100 ml of solution, then the solution was allowed to run off, reduced with hydrazine, rinsed and dried. Material was again scraped off the surface and this was examined by X-ray. The main phase containing calcium was found to contain gehlenite.

Experiments in the oxidation process The catalysts were tested by passing a gas of the following composition over them: CH ^ ₊ 0.3-0.4%, H ₂ 1%, CO 2.5-3.0%, O ₂ 3.5% 4.0 %, CO ₂ 15 %, H ₂ O 15 %, N _£ remainder, using a space velocity of 40,000 hours. We first worked at an inlet temperature of 700 ⁰ C and determined the content of CO in the flowing material. Then, the inlet tempera door to 800 ° C during a time that is specified in Table I was increased to the Kata ^"1 -sator to accelerated aging to subject. Then, the inlet temperature to 700 ° C was lowered, the measurements were repeated and the Temperature was raised again to 800 ° C for further aging
repeated up to a maximum of 450 hours.

800 ° C increased for further aging. This procedure was

409812/0834

Table I.

CO removal

Hours in o 25 50 74 202 450 use

Catalyst A (0.15% Pd) 95 95 - - 99 Catalyst B (0.23% Pd) 98 92 - 51 Catalyst C (0.01% Pd) 97 2 * 1 - - -

Catalyst D (0.08% Pd) 99-99 97

It is evident that Catalyst C absorbs very little palladium and despite having high activity initially quickly loses its activity for CO oxidation. The catalyst B, which contains colloidal alumina with a large surface area on the surface of the matrix block, retains its activity better than the catalyst C. The catalysts A and D, which are essentially the same and differ only in their geometrical shape, keep their CO oxidation activity very well.

Example 2

Platinum-gehlenite-cordierite catalyst carrier

A cordierite matrix primary carrier 10.2 cm in diameter and 7.6 cm (4 inches and 3 inches) in length was purchased from Corning Glass Works and contained 196 square passageways per 6.45 cm ² . This carrier

4Q9812 / 0834

ORIGINAL

... ₃ 4 -

was coated with gehlenite as a secondary carrier by dipping three times into a colloidally ground gehlenite slurry immersed. After each immersion, the coated matrix was dried at 120 ° C and at 1100 ° C Calcined during one hour. 8.0% by weight Gehlenite applied.

The gehlenite was prepared by kneading and extruding a at 1220 ° C for 12 hours wet mixture of the following composition

992 grams of alpha aluminum oxide

2144 g of heavy precipitated calcium carbonate, 864 g of bentonite

600 g of pre-cooked starch sold under the name "Kordek",

warmed.

The resulting product was finely ground dry and then grind in water in the ball mill overnight. The solid in the slurry was on a filter collected and then redispersed in water.

catalyst

The slide was immersed in a solution for 30 seconds pH of 7 from an ammonia complex derived from chloroplatinic acid, immersed, whereby a concentration used, with which 0.2% w / w. platinum

409 8 1 2/0834

could muster. The solution was then drained and dried.

Attempts at the oxidation of exhaust gas

The exhaust from a Ford Cortina 1,600 cc engine running at 30,000 rpm under a dynamometer load equivalent to 50 mph road conditions and the 99 octane fuel which was 54 ppm w / w. Sulfur, but not containing lead or phosphorus, was passed over the catalyst as described in Example 6A below to decompose the oxides of nitrogen to nitrogen. About 17 % vol / vol Air was introduced into the treated gas and the mixture was then passed over the platinum catalyst with an inlet temperature of 600 ° C and a space velocity of 3x10. The gases entering and exiting the catalyst were analyzed for hydrocarbon and carbon monoxide. The carburetor setting of the engine was chosen for most of the time so that a carbon monoxide content of 2.0 % was obtained. However, it was occasionally changed to give 1.5 % carbon monoxide so that the activity of the catalyst could be measured at this lower value.

The experiment was continued for a further 429 hours. The percentages of conversion of carbon monoxide and hydrocarbons are listed in Table II.

409812/0834 ORIGINAL! FiS

Table II

Percent Conversion, Time, Hours, Introduced CO 2%, Introduced CO 1.496

CO Hydrocarbon CO Hydrocarbon 30th 87 54 88 50 46 · 85 52 86 50 98 73 . 52 79 45 136 68 53 71 55 330 65 N / A 67 N / A 429 55 45 52 40

It can be seen from the table that the percentage conversion is well maintained, and it can be seen from this conclude that it is equally good when used in motor vehicles because the space velocity is lower there,

Example 3
Platinum-rhodium-gehlenite catalyst

A support was prepared as described in Example 2 and immersed in a solution of the lodiumchloriden ammine complexes of platinum and ^r ', wherein one such concentrations used that 0.07% of platinum and 0.03% of rhodium were deposited.

Experiment with the purely reductive treatment of exhaust gases Exhaust gases were passed off at 700 ° C. over the catalytic converter

409812/0834

the engine described in Example 2. The gas introduced into the catalyst contained 2000-2500 ppm v / v. NO. The setting of the carburetors of the engine was varied so as to obtain different levels of reducing force in the gas. The space velocity was 1.4 × 10 ^ hours "" ¹ . The activity of the catalyst was determined at intervals by determining the inlet concentration of NO and the output concentrations of NO and ammonia and expressing _{the results as rate constants k M.}

Table 3 shows the dependence of the NO removal activity on the reduction strength at different times. By graphing k _M versus reducing strength, it could be shown that the value of approximately 1.2 corresponds to the highest percentage conversion and that essentially conversions are obtained which approximately correspond to the stoichiometric conditions.

Table III

k. _T see

P.
Time, hours _

C0 + H ₂ -20 ₂ = 1.9 C0 + H ₂ -20 ₂ = 1.2 CO + H -2O ₂ = 0.7

3 87 26.5 50 45.4 40 73.4 27 98.1 30th

82 70 58 43 41 41 44 N / A 38 30th

409812/0834

It can be seen that the activity first falls, but that it then sets in at a practically usable value.

Example 4 Gehlenite Support: Nickel-Copper Catalyst

The following mixture was made:.:

992 grams of alpha alumina powder

2144 g of precipitated heavy calcium carbonate powder, 864 g of bentonite
600 g of pre-soaked starch that goes under the name

"Kordek" is sold 900 g of water

The ingredients were mixed well until the starch dissolved, then kneaded and screwed through an extruder by a 2.5 cm square shape that has 15 slots parallel to each side and 16 slots parallel to each Diagonal contained, pushed through, giving a total of 512 veins or passageways, each in the shape of one right triangle. The resulting multi-tube extrudate was dried, slowly heated to 1280 ° C. and during Calcined at 1280 ° C. for 10 hours. The product had the following composition in% by weight (calculated):

CaO ... 41 % Al ₂ O ₃ .. 37 % SiO ₂ ... 22 %

409812/0834

The porosity was 53 % v / v. and the specific surface area was 0.3 m / g. An examination of the X-ray diffraction spectrum found that it contained gehlenite as the main phase and monocalcium aluminate and a calcium silicate as secondary phases.

The bulk density was 0.6 g / cm and the material appeared to be firm and strong enough to be used in a reactor ' to be able to use in the treatment of vehicle exhaust gases.

It was impregnated with copper and nickel nitrates by immersing it in a mixed solution, the solvent drained, dried and calcined at 450 ° C. After immersing one, two and three times, the contents of nickel oxide and copper (II) oxides in Percentages determined. They are listed in Table IV.

Table IV

Impregnations .1

NiO 10.1 16.3 22.1 CuO 1.0 1.5 2.1

In this catalyst, the surface areas of the Catalyst represents the secondary carrier.

Activity and stability
Laboratory test

409812/0834 ORIGINAL INSPECTED

234173Θ

A 1.25 cm long piece of catalyst produced by two impregnations was tested with a gas having the following composition in percent by volume: CO 2.0, H ₂ 0.7, CO ₂ 13, H ₂ O 15 , O ₂ 0.3, NO = 1500 ppm, SO ₂ = 7-10 ppm, N ₂ «remainder. A flow rate of 550-600 liters per hour (space velocity 65000-70,000 hours" ¹ ) at a temperature range of up to 800 ° C. A similar catalyst *, which, however, was made of aluminum oxide bound to bentonite and which contained a coating of aluminum oxide trihydrate, was tested as a comparative sample.

A similar experiment was carried out after one had worked at 800 ° C. for 144 hours (new catalyst) or 76 hours (comparison). The conversions to Percentages of nitrogen oxides to nitrogen are shown in drawing I.

From the drawing it can be seen that

(a) the gehlenite-based catalyst is initially more active at all temperatures below approximately 700 ° C;

(b) the gehlenite-based catalyst is significantly more active at 500 ° C, i.e. it has a lower level "Response temperature",

(c) the gehlenite-based catalyst loses its activity much more slowly (from 99 to 90 in 144 Hours) than the alumina based catalyst (98 to 38 in 76 hours).

409812/0834

It was also observed that the activity of the catalyst on a gehlenite basis ·. · appeared after 144 hours.

Engine life

(a) A matrix 2.5 cm (1 inch) long by 11.4 cm (4 1/2 inches) in diameter with 288 passages per 6.45 cm (square inch) but of the same composition , was immersed three times in a solution of various nitrates. Each impregnation was followed by drying and calcining, and then the exhaust gas from the engine was examined as described in Example 2 at 800 ° C. The exhaust gas contained 2 Ji CO, 0.5 + 0.1 _{μl O 2} and 2000-2500 ppm v / v. N0 _v . It was over the catalyst

Jv

5 -1 with a space velocity of 1.7 to 2.0 χ 10 hours directed. The activity of conversion of oxides of nitrogen for nitrogen was determined over the course of 145 hours and expressed as a rate constant k «r. The values

2
were the following:

Time, hours 2 19 42

k _M 49 44 35

(b) After 145 hours at 800 ° C. it was evident that deactivation had occurred, which is negligible. The carburetors were adjusted to contain 4.0% CO in the exhaust gas and air was added to the exhaust gas so that there was approximately 0.5 % excess O ₂ (ie, over 2.5 % O ₂ or 13 % added Air.) CO, H ₂

409812/0834

62 78 100 125 145 53 51 47 46 40

and HC (hydrocarbons) is reacted with the O ₂ to give a strongly exothermic reaction, together with the., removal of more than 90% CO. For example, the temperature of the exiting gas was increased to at least 980 C, and the surface area of the catalyst was presumably much higher.

After the test had run under these conditions for one hour, the catalyst was tested again under normal conditions, ie at 2% CO and 800.degree. The activity was found to be better (68) than before. Under these conditions, aluminum oxide-nickel catalysts would lose their activity.

Change in activity in the air / fuel ratio

The catalyst used in experiment (a) was tested after 145 hours at 2% CO at various reduction rates, the air / fuel ratio being varied by adjusting the carburetor. This also changed the percentages of the other gases including oxygen and nitrogen oxides. The results are shown in Table 5.

It is seen that the activity is maintained at at least the stoichiometric values may be somewhat on the lean side.

ORiQiNAL iM3PECTED 409812/0834

234173Θ

Table V

H ₂ - 2O ₂
VoI. -% co / O ₂ 1.1 ^k N
2-1
sec co + --0.78. 0.8 - 1.5 O -0.5 -0.3 1.2 - - 1.75 19th -0.1 - +0.2 1.45 1.5 36 -0.04 - +0.3 1.2 ": - 2.0 41 -0.02 - 0.44 1.7 - 2.65 42 0.16 - 0.92 2.3 - 3.0 48 0.68 - 1.12 2.7 - - 3.75 48 0.88 - 1.5 3.35 3.95 47 1.24 - 1.72 3.7 - - 4.45 47 1.5 - 1.86 4.05 50 1.6 Example 5

Gehlenite matrix containing nickel and copper: calcination by exothermic gas reaction

The following mixture was "made:

992 g Ramsden alpha alumina powder g heavy precipitated calcium carbonate powder 864 g bentonite

600 g of pre-cooked starch sold under the name "Kordek"
g coarse powdered nickel oxide 100 g finely powdered copper (II) oxide

409812/0834

ORIQJNAL INSPECTED

The ingredients were dry and then mixed with water to form a thick paste. The paste was then kneaded and forced through an extruder screw with a 10.2 cm diameter mold with 11 slots per 6.5 cm (square inch) parallel to each side of the square and 12 slots parallel to each diagonal contained, making a total of 288 passageways or veins, each shaped like a right triangle. The slits were 25.4 χ 10 ~ ⁵ cm wide (10 χ 10 ^-5 inch). The resulting multi-tube extrudate was dried but not calcined. A piece of the matrix 3.2 cm (1.25 inch) long was placed in a converter in the exhaust pipe of the engine described in Example 2 using a similar fuel with a 101 octane rating. The exhaust gas contained Z% CO, 0.5 + 0.1% O ₂ and 2000 to 2500 ppm vol / vol. NO. It was passed over the matrix at 800 ^° C. and at a space velocity of 1.4 to 1.6 × 10 ^ hours, and then the nickel oxide and the copper oxide were reduced. The effluent gas was analyzed for nitrogen oxides and ammonia and the results were used to determine the rate constant k _M.

2 The value for k _M for the catalyst in incompletely calci-

^M 2
nated condition was 40.

The calcination of the catalyst was then stopped by adjusting the carburetor of the engine to obtain 4-5 % in the exhaust gas by introducing air into the engine exhaust line in somewhat excess relative to the CO.

409812/0834

The conversion of the CO with oxygen increased the gas temperature to about 1000 ° C, determined at the outlet of the catalyst. These conditions were maintained for 10 minutes, after which the air supply was completely stopped but the flow of rich gas continued until the catalyst had cooled to 800 ° C. The carburetor was then adjusted so as to obtain 2% CO. The value of k _M was now 100 seconds.

² _1

After 20 hours of operation, k _{N was} 65 see ", ■ within the next 70 hours, however, no further decrease was observed. <

The particle size distribution of the nickel oxide was as follows:

Table VI

2.5 5.0 Particle size distribution of metal oxide 7.5 Cumulative percent particle diameter
in microns 10.0 0.5 15.0 9.0 20.0 27.0 30.0 51.0 94.0 99.0 100.0

In this catalyst, the surface areas of the matrix make up the secondary support. The areas close to the

409812/0834

Surface form the primary carrier, although they contain nickel oxide and copper (II) oxide.

Example 6

Gehlenite as the secondary carrier on cordierite as the primary carrier

A. Gehlenite is applied as such by coating. A matrix of spiral cordierite with a length of 3.2 cm (1.25 inch) and 10.2 cm (4 inch) diameter obtained from 3M Corporation (American Lava Corporation) -

borrowed and which has approximately 450 passages per 6.5 cm (square inch), each having a cross-sectional shape of a figure bounded by sine waves and an arc, was coated with gehlenite by dipping twice into a colloidally ground 27 % wt ./Weight Suspension of gehlenite immersed in water. After each immersion, the coated matrix was calcined at 1000 ° C. for one hour. The percentages by weight of gehlenite applied were 6.5.

The gehlenite had been produced as described in Example 2.

B. Calcium aluminosilicate produced in situ

A matrix sample similar to that used in A was washed twice with saturated aqueous calcium nitrate solution impregnated. After each impregnation, the sample was calcined at 1000 ° C. for 1 hour.

409812/0834

C. Comparison sample: Matrix sample without pretreatment nickel-copper-platinum catalysts

Each catalyst support was coated with a pH 2 solution containing nickel and copper nitrates and amine-platinum (IV) chloride in proportions of 90.5 % NiO, 7.15 % CuO and 0.36% Pt , impregnated. The impregnated carrier was allowed to drain the solvent, then was added to; Dried at 130 ° C. and calcined at 650 ° C. for 4 hours. The impregnation was repeated once for catalyst support A and twice for catalyst supports B and C.

Process for removing nitrogen oxides A gas mixture that contained simulated gas from an internal combustion engine and that is expressed in terms of volume

1940 ppm CO 2 %

H ₂ 0.7 %

O ₂ 0.3 %

CO ₂ , N ₂ steam rest

contained, was over each catalyst with a spatial

4 -1

speed of 7 x 10 hours at temperatures in the range of 500 - 800 ° C. The experiments were carried out by increasing the temperatures one after the other at the beginning, then the experiment under steady-state conditions carried out for 60 to 90 hours at 800 ° C. Then the temperatures were gradually lowered. The contents of Nitric oxide and ammonia in the leaking material

409812/0834

were determined and used to calculate the rate constants first order used.

Table VII shows the values of k (u) for the tests with a continuous increase in temperatures, k (d) for the tests with a continuous decrease in the temperatures and the ratio k (d ), which is a measure of the activity ratio, which indicates after the steady state trial and other trials performed in this test.

4098 12/083 / »

2341

Pt '"ψ VII 4 71 k (d) k (d) 0.03 500 0 21 6.17 Tabel 550 0 34.5 1.73 600 0 42.8 1.21 Kataly- composition in
sator % w / w. 650 0 48.5 1.21 NiO CuO 700 0 52.5 1.09 A 10.3 1.1 750 Activity and stability 0 62.0 1.07 800 . k (u) .. time at
see "800 ° C
hours 8 71 70.0 1.29 0.03 500 3, 10.0 0.63 550 20, 18th 0.86 600 32, 28 1.0 650 '40, 37 0.95 700 A8, 45 0.83 B 9.8 2.3 750 53 56 1.02 800 54, 5 90 66 1.18 0.01 500 15, 5 2.6 5.2 550 21 4.0 0.38 600 28 5.8 0.16 650 39 6.9 0.104 700 54 5 8.6 0.10 C.
(Comparison) 22.9 1.4 750 55 9.4 0.09 800 56 N / A N / A 0, 10, 36 66 86 107 80

40981 2/0834

Example 7

Gehlenite on a matrix of bonded fibers A cylindrical matrix made up of bonded aluminum fibers existed and under the name "Febral" from the Societe Generale des Produits Refractaires is available with a diameter of 8 cm, an axial length of 3.4 cm and 105 passages, formed in parallel to the axis, 1.5mm wide, per

ρ
25 mm, was immersed in water and then soaked and treated with gehlenite from a 16% w / v. Slurry coated. The matrix was dried and calcined at 1200 ° C. for 1 hour. The procedure was repeated. The uptake of gehlenite was 13.6 % w / w. The coated matrix was then impregnated twice with a solution containing nickel nitrate, copper nitrate and ammine-platinum (IV) chloride. It was then dried and, after each impregnation, calcined at 650 ° C. for 4 hours. The nickel oxide content in the matrix was 34.7%, copper oxide 2.8% and platinum 0.05 %.

The catalyst was tested by passing exhaust gases from the engine described in Example 2 over it at 700 ° C. at a space velocity of 210,000 to 250,000 hours. The activity for the conversion of oxides of nitrogen to nitrogen was determined over 193 hours and reported as the rate constant k _M.

While the experiment was being carried out, carburetor adjustments were made from time to time so that CO levels of 2.0 or 1.5 % v / v. received, and the

4098 12/0834

ORIGINAL '.'-' Gr

2341735

outlet and outlet concentrations of carbon monoxide, oxygen, Oxides of nitrogen and ammonia were used in both carburetors. positions determined. The results are shown in Table 8.

ORIGINAL JNSFECT 409812 / 083A ⁱ

ω ■ Η r-i CD .Ω

Ss-P ο ω

■ ρ m

tio-H ro CD

O CMO)

cd O UO

CMbO O w

CMtß O Ö

cd O W)

fco O cd

U Ö Φ O)

(M -4

VO

IfV

co ο

IN

CM

CM CM

ιη

m to

O ^ CO

in in

in ro

O

• 4- -4-

O

in u \

O Ο ο Ό co in τ- ω CTi

CM

O O

00 VD

in in

CM

Q

cn ο

O CM

in ο

τ- CM

CM

ιη

VD ro

in

00

ro ro

tn cor- ro

IN

CM

νο ro

CTv

2320 O
CM 2400 2480 1460 1600 1350 1540 0.08 O 0.02 0.07 O O 0.06 0.10 in tn VD
4th VD
in CM
CM ro
ro ■ 4
ro co
m

ιη

2341735

409812/0834 ORlGfNAL! NCrHCTE

It can be seen that the catalyst is still an essential one Activity "after running for 193.6 hours.

Example 8

Gehlenite on cordierite: nickel-copper-platinum catalyst test over the service life with different reductions strength

A sample of a synthetically made cordierite matrix with a volume of 260 ml and approximately 300 fermentations per 6.5 cm (per square inch) each with a cross-sectional shape of figures bounded by a sine wave and a straight line was passed through with gehlenite two impregnations, as described in Example 7, coated. The uptake of gehlenite was 12.7 % w / w. It was then impregnated three times with nickel-copper-platinum solution, as described in Example 7. The nickel oxide content was 17.0 %, copper oxide 1.4% and platinum 0.1 %.

The catalyst was tested using the engine described in Example 2. The rate constant k _M was determined for different carbon monoxide values in India

intervals in an experiment of 99 hours, an inlet temperature of about 700 ° C. and a space velocity of 140,000 hours. In Table 9, the inlet and outlet contents of carbon monoxide, oxygen, nitrogen oxides and ammonia and the values of k _M after one

2 operation of 23 and 99 hours listed. It can be seen

that there is essentially no loss of activity.

409812/0834

O)
H
H

ω, α
CD

IO

pi

ft

H 3

S PP ₁

αϊ -λ ω d

■ A

CM
O

(U

rf
H

ω 3

cö

ctj
ω

co

ίΐ

ti

tt »

CO

CM

vo
in

(M

O O in

m
CM
(M

O
O

VD O

O is-

O
c \ j

ro

O O

CM

O C-

CTi
O

(M ΙΓ \

CM O

to <r

IS- IN

ro

C-C-

c \ J vo eg ro

O CM O CM

O O

ο-

CM

C- -

in in r-σ ^ ο ο vo is- is-

ΚΛ
CM

VD

in

O O CM CM

O VD

O O

CM

in <ί · ro ro

»T« V «t *»

O O O O

CM

in

CM

C-C-

C-

vo

ο ω

CTi

ο ο

CM CM

O O

ro

VD

cm

CT>

CM CTv

is-

VO IS-

in ro

ο ro ro

CM T- CM

O O

in

ιη

in <t ο ο c- c-

ο cm

Vs.

CTv

ro

ο ο ο

CM

ro

in ο in in

IS-

O

σ \ co

ο ο "

f ro

«Ο

CM

m ο (Ti

ΚΛ CM ir t- is- r> -

V- VI)

ο σ>

IS VO

2341735

409812/0834

Example 9

A sample of catalyst similar to that used in Example 8 but containing approximately 450 passages per 6.5 cm (per square inch) was subjected to an extended use test at a falling speed of 165,000 and a carbon monoxide content of 2%. The values of up to 62 hours are listed in Table 10, together with the oxygen levels obtained at the time of measurement.

Tabel. X

Time in hours 3 22 47 94 134 183

O ₂ % 0.41 0.46 0.51 0.46 0.46 0.45 0.34 k _N 113 108 113 96 99 81

It is evident that the catalyst retains a substantial part of its activity after a period of time corresponds to an operation of 20,920 km (13,000 miles).

Example 10

Copper-chromium oxides with palladium on gehlenite on cordierite A catalyst support was produced as in Example 2 and placed in a 14% w / w which had been ground in a ball mill. immersed aqueous suspension of copper chromite. It was then dried at 120.degree. C. and calcined at 650.degree. C. for 4 hours. This procedure was repeated twice.

409812/0834

23417: i

get. The total amount of copper consumed was 12.2%. The resulting coated carrier was immersed in a concentration Pslladiumnitrat be \, which was calculated to 0.05 '''·Oe'v. / BB ^M v. Palladium. Subsequently were applied was allowed to proceed, the solvent and dried.

Experiment with the oxidation of exhaust gases The catalyst was examined as described in Example 2, , but a space velocity of 1.6 10 "hours. The conversions of carbon monoxide and hydrocarbons, expressed as a percentage, are in Table XI listed.

Table XI

Time, hours Conversions in percentages

Inlet CO 2 % Inlet CO 1.5 % CO hydrocarbon CO hydrocarbon

2 ♦ 2 92 , 4 69 , 9 80.7 74 , 7 hG , 2 86 , 2 .61 , 5 N / A N / A 65 84 , 9 58 , 3 92.9 67 ,1

It can be seen that the catalyst loses its activity only very slowly.

Example 11

Behavior of a nickel-copper-platinum-gehlenite-cordierite catalyst in the NO removal in the US Federal test A 4 cylinder British Leyland Marina engine with a capacity

409812/0 83 U

ORiGiNAL i ^ CP ~ C7 £ D

A capacity of 1796 ecm (112 cu.in) and a compression ratio of 0.8 obtained with a reactor (1) mounted adjacent the cylinder head containing the NO removal catalyst and a conduit containing an air injection nozzle and leading to a reaction reactor (2) was used. The engine was run on 91.7 Research Octane (82 motor octane) gasoline containing 0.016 % sulfur (as S) and 0.0022 g of lead (as Pb per 3.8 liters = 1 US gallon). The engine was operated using a dynamometer containing a mass weight equivalent to a vehicle weighing 1130 kg (2500 lbs). The carburetors were adjusted so that the exhaust gas contained 2-2.5% carbon monoxide.

The catalyst used was:

(1) the catalyst described in Example 9 in the form of matrix units with a diameter of 10.2 cm (4 inches) and a length of 3 inches

(2) a branded oxidation catalyst in the form of 3 matrix units 10.2 cm (4 inches) in diameter and 7.6 cm (3 inches) in length.

The catalysts were set to operating temperatures warmed up by gradually introducing air into the inlet port of the reactor (1) at the beginning of the cold start, but not at the start, which followed a 10 minute standstill. The emission rates in grams per 1.6 km (per mile) cheat

409812/0834 ⁰ ^ HAL iWSPi-CT. ·?

Hydrocarbon 0.16 (Federal standard 0.41 CO 0.72. 3.4

NO _v 0.18 0.40)

40981 2/0834

Claims (10)

Potential claims b e 1. Carrier for a catalyst necessary for the treatment of exhaust gases is suitable for internal combustion engines, characterized in that it has a primary catalyst carrier, the carries a refractory secondary catalyst support, and wherein the secondary support consists essentially of one or several acidic and / or amphoteric oxides consists essentially of one or several basic oxides from groups II, III or IV of the periodic table are combined or bound. 2. Carrier according to claim 1, characterized in that the acidic oxide is an aluminosilicate of calcium, strontium or barium is used. 3- carrier according to claim 2, characterized in that the secondary carrier contains gehlenite. H. Carrier according to one of the preceding claims, characterized in that the secondary carrier has a porosity in the range from 30 to 70 volumes ~ 96. 5. Carrier according to one of the preceding claims, characterized in that cordierite is used as the primary carrier used. 409812/083 /. ORiGiNAL IHSPECTiO 6. Carrier according to one of the preceding claims in Form of a multi-tube matrix. 7. Use of the support according to any one of claims 1-6 for the production of a catalyst for the treatment of exhaust gases of internal combustion engines, the catalyst containing platinum or palladium as the active metal and for the oxidation the exhaust gases is determined. 8. Use of the support according to any one of claims 1-6 for the preparation of a catalyst for the treatment of Exhaust gases from internal combustion engines, the active metal being a combination of platinum and rhodium and the catalyst is intended for the reductive treatment of the exhaust gases. 9. Use of the support according to any one of claims 1-6 for the preparation of a catalyst for the treatment of exhaust gases from internal combustion engines, the catalyst being the active material metallic nickel or cobalt or an alloy of these metals and possibly copper or silver or one or more of the platinum group metal Contains metals, and wherein the catalyst is intended for the reductive treatment of exhaust gases. 10. Use of the carrier according to one of claims Λ - for the production of a catalyst for the treatment of exhaust gases from internal combustion engines, wherein the catalyst as 409812/0834 L INSPECT - -51 - active material 1 or more oxides of nickel, cobalt, copper, manganese or chromium and possibly, also one Contains platinum group metal and wherein the catalyst is intended for the oxidative treatment of exhaust gases. ORIGINAL INSPECTED 409812/0834 Blank page