DD150491A6 - METHOD AND DEVICE FOR THE CATALYTIC TREATMENT OF GASES - Google Patents

Abstract

The invention relates to a method and apparatus for the catalytic treatment of gases, in particular exhaust gases from internal combustion engines, for example, motorcycles, chain saws, small electric generators u.a., In oxidation systems for the purpose of removing, for example, hydrocarbons and carbon monoxide from the exhaust gases. The aim of the invention is an improved process in which damage to the catalyst system due to excessive temperatures or clogging by solid particles are avoided. According to the invention, a device is used for the treatment of exhaust gases, in which the catalytic system consists of a first catalyst body having a plurality of flow channels with Einlasz- and Auslaszoeffnungen and a downstream catalyst body of the same education, but the open cross-sectional area of the individual flow channels of the first Katalysatorerkoerpers essential is greater than that of the downstream second catalyst body. According to the inventive method, the solid particles are reduced upon entry into the first catalyst body. The in d. Catalyst bodies generated temperatures are not so high that they are harmful to the catalysts.

Description

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Process and apparatus for the catalytic treatment of gases

Field of application of the invention

The invention relates to a method and a device for the catalytic treatment of gases, for example, exhaust gases from internal combustion engines according to patent 133 058 (AP F 02 B / 201 374).

The system according to the invention is suitable for the catalytic oxidation of solid or particulate gases containing oxidizable constituents, such as one or more hydrocarbons or their oxidation intermediates, such as carbon monoxide or oxygen-containing organic materials. The terms "particulate matter" and "particles" are intended to include, in addition to solid particles, liquid droplets or aerosols as well as mixtures of liquid and solid particles. In the exhaust gases of internal combustion engines, liquid particles of unburned or partially burned liquid fuel and / or lubricating oil that enters the exhaust gases may be formed. Solid particles may result from the combustion process and form within the internal combustion engine and / or the exhaust system. Solid material can also form on the catalyst due to carbonization of liquid particles encountered by the catalyst. Therefore, if solids or solid particles are mentioned, liquid particles should also be included, unless otherwise stated in the context.

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The to be treated G _a s a sufficient amount may include of oxidizable components, so that the catalytic system can be used as a primary energy source, or the oxidizable components can be present in the gases in smaller amounts, such as in ^A bgasen _f which contaminate the atmosphere For example, in the latter case, the feed gases may be exhaust gases having a relatively high concentration of carbon monoxide and hydrocarbons, and these gases may be catalytically purified to reduce the contamination of the gas To reduce the atmosphere »

In one aspect, the present invention relates to catalytic processes and apparatus suitable for venting gases, such as exhaust gases or exhaust gases from combustion processes or other sources, to reduce atmospheric pollution The present invention solves problems encountered in the purification of gases, particularly exhaust gases of two-stroke internal combustion engines having relatively high concentrations of hydrocarbon and carbon monoxide. "

It is known that internal combustion engines emit various gases, and. Often these gases contain undesirable components which, when released into the atmosphere, constitute air pollutants

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Minimizing the release of such pollutants to the atmosphere has been in the art for many years, and it is becoming more and more important to find means of eliminating the emission of air pollutants, such as the operation of engines employing relatively large quantities of hydrocarbons and hydrocarbons Carbon monoxide emitted from the internal combustion engine are particularly troublesome for the effective control of the emission of air pollutants. Examples of sources that are typical for the delivery of such large amounts of hydrocarbons and carbon monoxide are internal combustion engines, especially two-stroke internal combustion engines, which are often used to drive motorcycles, outboard motor boats, snowmobiles, chainsaws and small electric generators.

It is known to eliminate such exhaust gases by treating them in a catalytic oxidation system consisting of a one-piece catalyst body with flow channels and containing a platinum group metal as the oxidation-promoting constituent.

But such gases may also contain solid and / or liquid particles, which may lead to blockage of the flow channels of the one-piece catalyst body, which applies to the same extent for the exhaust gases or A _US p _U ffg _a se of gasoline or ^ ieselkraftmaschinen.

Motorcycle hydrocarbon emissions are estimated to be about 0.9 % and carbon monoxide emissions from motorcycles to 0.6 % of the total emissions of motorcycles

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In the United States of America, the consumption of seasonal motorcycles and the higher concentration of motorcycles in large cities may make the effect of the emission of motorcycles on the air quality more significant at certain times of the year " ^ ohemission of two-stroke engines of motorcycles may B _{0 e} frequently be in the range of about 6.25 to 11.25 g hydrocarbons per lan and from about 7 .5 to 17.5 g of carbon monoxide per lon Z, and the leading back to this motorcycles Emission of hydrocarbons and carbon monoxide may even be as high as that of 10 to 20 passenger cars equipped with catalytic converters for the exhaust gases "E-in typical exhaust gas of a two-stroke engine of a motorcycle _f with an air-fuel ratio of 12, 8 works, on a volume basis about 5 ^ carbon monoxide, 1.7 % hydrogen (geschä less than 1/3 of the amount of carbon monoxide in the exhaust gases), 3 % oxygen and 2,000 ppm hydrocarbons, and have a temperature greater than 540 ⁰ C *

Carbons, such as natural gas and oxydier "bare bgase of ordinary vehicles, ¹ -are generally relatively free of particulates, at least of such considerable size, and they have-oxidizable constituents. However, fuels may also come from other sources, and they may contain various amounts of interfering particulate matter dispersed in the gases. "K-ine" Sufficient separation of these particulates from the oxidation of the gases may be from economic or technical reasons are not

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However, these particulate materials can be significantly detrimental to the catalyst

These catalytic oxidation systems, especially when containing a platinum group metal oxidation promoting component, have a long life and a high catalytic activity, and suitably become in a substantially fixed position with respect to the gases Such catalysts are often used for long periods of time without replacement or regeneration treatment, or needing to be otherwise treated to counteract the shortening of a long life Catalysts are in the form of one-piece structures having a large number of relatively narrow gas flow passages that pass through the catalyst body. This configuration provides a relatively large geometric surface area for a given volume and thus provides t for extended surfaces on which an active catalytic composition can be distributed to enhance the ability of the catalyst to handle increased amounts of gases in a given period of time. Compared with, for example, one particle of catalyst particles, the gas flow channels also show relatively low vapor decay characteristics »

With respect to these one-piece catalyst bodies, it is apparent that the smaller the flow channels are in cross-section, and the greater the number of channels in a given cross-section, the greater the surface area of the channels.

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contact area, and the more effective this is because of the oxidation system, but if the flow channels are smaller, they become more susceptible to adverse effects such as clogging by components or oxidation products contained in the gas fed in. These difficulties become greater when gases of this type, which present particular difficulties, are those which contain suspended particulate matter, including solid particles, which, although relatively small and light enough, have been found to produce more clogging problems of the unitary catalyst bodies. to be carried away by the gases are not susceptible to separation without being subject to technological difficulties or economic hardships. These particles may be so large as to affect the flow channels of the integral catalyst used to promote the oxidation of the gases clogging and thereby lead to an increasing pressure drop of the gases to be treated and to a reduction of the geometric surface, which is available for the contact with the gases. These effects are extremely disadvantageous because one of the reasons for using a one-piece catalyst is in the advantage of having a higher geometric surface area and exhibiting lower pressure drop characteristics

Although there is a general technique for treating undesirable components in exhaust gases; However, the application of this general technique to the treatment of emissions containing relatively large amounts of hydrocarbons and carbon monoxide faces significant obstacles. "

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P _e rn containing exhaust gases from, for example, two-cycle engines and other engines, such as for EXAMPLE diesel engines may generally contain smoke, the black carbon black particles, white aerosol and oil ash, as is consumed together with the Treibstoff'auch lubricating oil. The white aerosol (white smoke) can coat the catalyst and block the catalyst along with the black soot particles. Also oil ash can clog the catalyst and contribute to the poisoning of the catalyst. "The propensity of two-stroke engines to leave deposits can often be observed by examining the exhaust pipes after a certain period of time

Not only does exhaust system affect the performance of the engine and the catalytic converter, but the counterpressure that results from it also promotes an increase in the formation of impurities.

In the catalytic treatment of exhaust gases from various sources, such as exhaust gases from internal combustion engines, thereby causing problems that due to the high temperature of the exhaust gases to be treated and due to the expiration of exothermic reactions very high catalyst temperatures can be achieved, which damage the catalyst » These problems are aggravated when the exhaust gases contain relatively high concentrations of carbon monoxide and hydrocarbons together with molecular oxygen. "

The presence of relatively large amounts of carbon monoxide and hydrocarbons in typical exhaust gases or exhaust gases can result in significant thermal stress on the oxidative oxygenation system. ^lJ o is to

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Example of adibatic temperature increase in the catalytic. Combustion of 1% by volume carbon monoxide in combustion gases often about 85 to -90. ⁰ C, the carbon monoxide concentration in the exhaust gases of engines, such as two-stroke engines, may even be about 10% by volume or more. Combustion systems are often operated under fuel-rich conditions, and then their exhaust gases may easily contain greater amounts of hydrocarbons, for example, up to about 1 vol. And more. In addition, engines may misfire, in which case substantial amounts of hydrocarbons and oxygen are emitted from the fuel The hydrocarbon concentration in the exhaust gases may even be 2 % or more in the case of misfire. Hydrocarbons and oxygen are also due to the normal flushing process in the cylinder, in which part of the mixture of air, fuel and combustion oil without substantial combustion passes from ^ inlaßkanal to Aufρufföffnung, uspuffgasen in the ^A contain "the adiabatic temperature rise in the karalytischen combustion of 1000 ppm hydrocarbons in the exhaust gases is about 100 ⁰ C ,, P can raer _e high at times fuel consumption, z" B * when operating under heavy load and / or with high G Thus, the thermal load to which catalysts are subjected in the treatment of combustion emissions may be strong, especially the rates of the volume of exhaust gases to be treated In addition, high fuel consumption, as well as total or partial misfire, may theoretically exceed the upper temperature range for effective catalyst operation

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and even lead to melting of the catalyst carrier »

The ^iL uspuffgase pulsate from the cylinder of an internal combustion engine, since it only during - are emittert ^ uspuffperiode. Two-stroke engines are usually equipped with a special exhaust system for each cylinder "Therefore, the pulsating flow is generally more pronounced in combined Äuspuffströmen for example, multi-cylinder motor vehicles ,, feiese pulsating flow can uspuff the placement order of ^A ~ gas catalyst affect as well as stress in the KataJLysatorstruktur lead yourself. It has also been found that, generally in two-stroke engines, the direction of the exhaust flow may temporarily reverse. ^In this way, catalytically burnt exhaust gas can be sucked back into the catalyst, which further aggravates the pulsation effect and the increased thermal load of the catalyst. "

US Pat. No. 2,664,340 describes a catalytic device and a catalytic process for the treatment of waste gases which gas with a plurality of catalytic elements connected in series. Each grouping of downstream catalytic elements is catalytically more active than the previous grouping of catalytic elements, and cooling zones are located between all of the groups of catalytic elements. US Pat. No. 3,440,817 describes a catalytic treatment system for exhaust gases in which a smaller catalyst occurs immediately Adjacent to the engine and a larger catalyst are arranged behind the smaller catalyst «^ Or the smaller catalyst be»

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There is an adjustable diverter, through which so much of the exhaust gases can be deflected around the smaller catalyst around, that the formation of harmful high temperatures is avoided.

U.S. Patent 3,785,781 discloses a one-piece catalyst system for treating exhaust gases, wherein the first catalyst with which the gases come into contact has relatively small flow channels and is followed by a one-piece catalyst body has larger flow channels. This arrangement is repeated and the purpose of the larger flow channels present in the subsequently arranged one-piece catalyst bodies is that they cause favorable plumping properties of the gases, for example due to turbulence, in order to make the treatment in the one-piece catalyst bodies with the smaller flow channels more effective. " The use of feed gases containing particles of such a size as might clog the smaller flow channels of the first one-piece catalyst body is not mentioned there, nor is this problem ever addressed in this patent

U.S. Patent 3,896,616 discloses a method and apparatus for treating exhaust gases containing carbon monoxide, hydrocarbons and oxides of nitrogen. The apparatus includes first and second catalytic converters. The first catalytic converter operates under oxidizing conditions to heat up the second catalytic converter. Then the first catalytic converter is allowed to pass through . : Addition of fuel to those in the first catalytic

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Converting exhaust gases operate under reducing conditions to reduce the oxides of nitrogen, and the second catalytic converter oxidizes the combustible components contained in the exhaust gases. These patents are typical examples of the catalytic treatment of exhaust gases two or inner catalyst bodies »

Other technical solutions of the Probelins include USAGE dung of catalyst bodies with a variety of flow channels in which the respective channels are the same size, or wherein the gas flow channels less and large size are present, wobei'das original part substantially channels less Gp _o * SSE U.S. Patent 3,928,961 discloses a catalytic combustion system of the same general type as in the present application, but does not show or suggest the use of gas flow channels of originally wide cross-section diameter, followed by gas flow channels of lesser cross section,

The aim of the invention is to provide an improved process for the catalytic treatment of gases, such as exhaust gases of internal combustion engines, in which damage · of the catalyst system due to high temperatures or ^v erstopfung avoided by Peststoffteilchen be ,, .. ·.

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The invention has for its object to solve the constipation problems by using one - one of one-piece catalyst bodies, of which the first has relatively large flow channels to prevent clogging, and at the same time the size of the fixed and / or or liquid 'particles in the gas, either by chemical destruction, such as oxidation, or by mechanical reduction, or both, while maintaining the benefits of high geometric surface area of the unitary catalyst bodies, and thus greater catalytic efficiency, in that the one-piece catalyst body or bodies arranged subsequently have smaller flow channels.

By the present invention is a catalytic. Found system is provided, which consists of at least two integral areas _s wherein the first region or "having section gas flow channels, which have a substantially larger cross section than the flow channels in the (or to) subsequent zone (s) or section (s)"

The particulate matter in the feed gas may be so large as to obstruct the narrower gas flow channels in the laterally disposed catalysts unless the contact with the first, larger, one-piece catalyst serves to increase the size of the particulate matter contained in the gas Shrinking fabrics «,

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The first one-piece Katalysatorbereicli with the larger flow channels, the. Solids or * gases contain, absorb the particulate substances and process without adverse effects such as clogging of the channels, can be observed * By treating in this first integral catalyst zone, the particulate ^ö can toffe at least partially destroyed or with regard to their size are reduced mechanically and are then a more suitable orm for further treatment, or at least they can pass through the laterally arranged one-piece catalysts without their being subject to harmful influences. If, moreover, it appears desirable to determine the degree of combustion and thus the To limit the temperature rise in the catalyst system, the larger flow channels reduce the surface area available in the first catalyst region, allowing for relatively low combustion and thus operating at a relatively low temperature. An intervening cooling stage may be provided to reduce the temperature in the second stage.

The present invention catalytically provides methods and apparatus for the oxidation of gases containing solid particles, such as the gases described above, particularly gases which are used to power primary energy sources, and exhaust gases or "exhaust gases from internal combustion engines". The oxidizable. Gases are catalytically treated together with free or molecular oxygen using

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a suitable piece .Oxydationskatalysatorsystems, wherein the first catalytic region has gas flow channels that are sufficiently large to 'treat the supplied gas without undesired blockage of the flow channels occurs, and in which a downstream-piece catalytic body smaller flow channels having ₉ by the in that. Gas contained particles could be clogged if the first arranged one-piece Katalysabrkörper would not be present with the larger flow channels. The latter obviously serves to reduce the size of the particles sufficiently, either by chemical conversion or mechanical reduction, so that the particles do not clog or otherwise adversely affect the smaller flow channels of the subsequently arranged unitary catalyst bodies. The present invention may be or also carried out as · applied without too high temperatures are achieved over a wide range of throughput volumes and working conditions of the source of the gas, for example a. the internal combustion engine in the case of treating their exhaust gases to prevent ^v erunreinigung. the atmosphere, affecting the catalyst "In the catalytic process according to the invention, after start-up, fast temperatures are reached which are suitable for activation of the catalyst, and it is possible to quickly adapt the process to changes in the working conditions of the source, from which the gas comes from. "Further, the invention achieves the elimination of undesired components of such gases without adversely affecting the operation of the source, such as, for example, an internal combustion engine without, for example, over-training

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Back pressure or other difficulties, the methods and devices according to the invention are particularly suitable for the treatment of the exhaust gases of diesel engines or two-stroke engines with pulsating flow of the exhaust gases. The exhaust gases may include particulate matter, white aerosol, oil ash, and the like, and misfire and cylinder scavenging may occur resulting in exhaust gases containing large quantities of unburned fuel and oxygen

In any of the systems of this invention, the gas inlet end of a downstream one-piece catalyst body having substantially smaller flow passages than the first arranged catalyst body may be located near or in contact with the first arranged catalyst body. The first catalyst body of a system for treating exhaust gases of an engine or exhaust gases or combustion gases resulting from another source may be arranged so that the gas is not subjected to catalytic treatment between the exit from the source and the first catalyst body according to the invention , The catalyst body subsequently arranged thereon thus preferably lies in the same catalytic treatment as the first catalyst body. Alternatively, the downstream catalyst body (that with the smaller flow channels) may be located in a catalytic treatment zone that is separate from that of the first catalyst body (the one with the larger flow channels). In the various cases where oxygen is already present in the gases, preferably no significant amount of free oxygen is present,

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For example, in the form of air, added _s before the gases come into contact with the one-piece catalyst body having the larger flow channels, "In fact, such an addition can be avoided until the gases exiting, for example, from the catalytic Seha .ndlungszone that the catalyst body with the larger flow channels, and sometimes the addition to any part of the system may not even be needed or desirable «»

According to a dissipation g ^ ₀ ^ form - ^he included invention to control the pollution of the atmosphere by components of gases and particulates for example, comprise carbon monoxide and hydrocarbons and free oxygen, the gases are preferably without any substantial addition of further free. Passing oxygen to a first catalyst zone containing a one-piece oxidation catalyst which undergoes oxidation sufficient to increase the exhaust gas O-temperature but insufficient to produce temperatures in the catalyst which could damage the catalyst. ^ ie emerging from the first catalyst gases contain combustible valuable substances, such as carbon monoxide and hydrocarbons, and are cooled and then passed into at least one downstream catalyst zone comprising an oxidation catalyst and in which the leave-combustible ^w ertstoffe be further oxidized "

Often, one need only use a first or a first and a second catalyst zone; however, especially

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in the treatment of exhaust gases having higher levels ^of carbon monoxide and hydrocarbons, further catalyst zones, preferably, with one-part catalysts, may be used to avoid the need for substantially complete oxidation reactions and generation at high temperatures in the first catalyst zone however, the total content of undesirable components in the catalyst is sufficiently reduced. Between the individual catalyst zones downstream, if flour is used as such a zone, the gases are preferably cooled before being passed to the immediately following catalyst zone a preceding catalyst zone coming exhaust gases lose the gases as much ^Vi 'Slee that does not occur during the combustion in the next catalyst zone for forming temperatures, which are detrimental to the catalyst, but the temperature decrease in the cooling should not be so great _s that gases, which still contain significant amounts of combustible substances value, be cooled below that temperature which is required for the activation of the catalyst for the oxidation of combustible materials in the gases value in the next catalyst zone ₀

According to a feature of the invention, particulate matter-containing oxidizable gases, for example, a primary fuel or exhaust gases of internal combustion engine, are catalytically treated in a catalyst zone in which a suitable oxidation catalyst is in each of at least two cascaded, adjacent ones Each of the one-piece bodies has a plurality of channels extending to one another

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extend through a single piece of catalyst and which are open to the fluid passage and therefore not plugged or obstructed against the flow from one inlet to a separate outlet. The first of these. Catalyst body pending the flow of gases has channels of a sufficiently large cross-section to facilitate the entry of many, if not all, particles in the supplied gas, for example, black carbon black particles, white smoke aerosol, and the like into the channels. The solid particles, especially if they are sufficiently brittle or brittle, can be reduced in size by hitting the end face of the first one-piece catalyst body, wherein the sides of the skeletal grains form the flow channels. The reduction may facilitate the entry of at least some of the solid particles into the relatively large channels of the first one-piece catalyst body. The liquid and solid particles in the feed gas enter and pass through the flow channels of the first unitary catalyst body as they are reduced in size, particularly the solid, oxidizable constituents of the gases, and may even be completely destroyed as solids can By one or more of these effects, the gases themselves can pass through and exit the one-piece catalyst bodies having the smaller flow channels without these materials being deposited on the walls of the catalyst or discontinued, which could lead to a restriction of the gas flow and even to a blockage of the channels.

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By combustion in the first catalyst body, the gases passing therethrough are heated and the tendency of, for example, carbon-containing particles, white oil aerosol and the like to form deposits on the catalyst walls is reduced. The heated gases flow from the first catalyst body into the next, for example, adjacent catalyst body _f which may touch or be spaced from the first catalyst body, for example at a distance of not more than about 2.5 ee, this next catalyst body has each cross-section a larger number of smaller flow channels than the first catalyst body to provide an additional active surface to enhance the catalytic! Combustion of the combustible ^w ert ~ materials in au treated gases to provide more catalyst bodies can be prepared by or arranged trömungskanälen with the smaller ^ even before the said next catalyst body to be, and this can be substantially the same, a larger or ei'ne smaller ^ These additional catalysts may be located in the same gas treatment zone or in a gas treatment zone other than the one in which the first or the next catalyst body is located, ie the larger active surface area in the catalyst the next and subsequent catalyst bodies with the relatively small flow channels increase the degree of chemical conversion of the gas fed per unit of volume. Therefore, one can work with a smaller catalyst volume than would be required if the flow rate were to be reduced ußkanäle

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in the downstream catalyst bodies would be the same size as in the first catalyst body, and the counterpressure due to the catalyst can be reduced, as excessive deposit formation is avoided. "The first catalyst body which can be rapidly heated to catalytically effective temperatures _f is used to increase the temperatures of the gases that pass to the subsequently arranged catalyst bodies, and it serves to accelerate reaching the temperatures at which the catalytic oxidation takes place in äen later arranged catalyst bodies or promoted. During operation of the coolest ^ ¹ eil of the catalyst body, in general, be the first '-'-' eil where the gases to be treated come to the top with the catalyst into contact. Since the next catalyst body with the narrower or smaller gas flow channels per volume unit has a larger catalytically active surface, the temperatures reached in it due to exothermic combustion reactions are sufficiently high that heat is radiated to the first catalyst body and thus the catalytic combustion in it is accelerated can. The catalyst system having the above-described first and subsequently arranged catalyst bodies with different number of flow channels in them can be used in the process according to the invention, which operates with at least two catalytic zones, or in any other catalytic process for the treatment of gases of the above-described jftc

Process and apparatus according to the invention are particularly suitable for treating gases which, for example, are minimized.

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at least about 2 vol, carbon monoxide and at least about 0.05 vol% hydrocarbons (calculated on the basis of CV hydrocarbons). These gases also contain free oxygen, and may also contain other constituents, such as hydrogen and inert diluents, such as nitrogen, as well as end products of combustion, such as carbon dioxide and water. Free oxygen is generally present in the exhaust gases of internal combustion engines due to misfires or other incomplete combustion of the fuel in the engine, due to the normal Zylindgespülproaesses and the Ver. application of fuel-lean combustible mixtures, or due to the use of a stoichiometric excess air in the to be combusted fuel-air mixture containing "Often the exhaust gases of two-stroke internal combustion engines contain under normal working conditions, on average, about 2 to 8 VoI _e ~% carbon monoxide, about 1 to 2, 7 VoI · -% hydrogen, about 0.05 to 0.8 vol SS coals "hydrogens and about 0.5 to 5 ol ^v _o - $ i free oxygen In the misfire or bu times of the start-up or high loads can ^G ehalt still be significantly higher of the exhaust gases of combustible ingredients. The exhaust gases from • a misfire can z * B _e about 2 or more VoI _β - ·% hydrocarbons contained

Apart from the fact that by means of the invention the pollutants of the environment can be converted to exhaust gases, also gases of various types , both inorganic and organic oxidisable materials, can contain interfering solid and / or liquid particles, as described above.

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are oxidized "These gases often have a kohlenwassersto'ffhaltige Uatür primarily, and · they have a greater amount of oxidizable constituents as waste gases barren exhaust gases _s example, at least about 5 or 10 by volume, -% or more and up to 100% of such components "Among these materials, primary fuel gas mainly composed of, for example methane or other hydrocarbons present in the gaseous state, at least when they pass catalysts of the invention", respectively These primary fuels "fuels can, at least for the greater 'J- ¹ eil, before any combustion process be unterzogen'worden and are therefore non-burnt materials, "^ le & s systems can be used for example as heat radiation sources or to generate Bev / egungs energy or operating power directly or indirectly. · in, for example, more or less adiabatic systems or for Heating ode r warming through. Convection or transmission, such as in heat exchangers or boilers. Examples of some Sy ₃ -J - _eme this type are described in US Patent No. 3,846,979, 3,914,090, 3,928,961 and described 3,982,879, the entire Offenbarungliier covered with should be.

The oxidizable gases used in the names of the present invention contain interfering solid particles suspended in them, or are entrained to other else "At least a substantial ^x eil this' .Teilchen is so large that they lead to clogging problems in the subsequently arranged integral catalyst bodies may have the smaller ^ö trömungskahäle "the particles have to. overwhelming share or nearly all of them

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Size that / she trömungskanäle in the ^ of the first catalyst body integral with the larger ^u trömungskanälen may occur, or the particles have at least such a size then when skeletal the

Structure of the first one-piece catalyst body in

Contact are made, since the ^x eilchen, especially if they are brittle or fragile, can aufgebrochen.werden to a smaller size and therefore in-can enter the flow channels of the first catalyst "While the particles in the gas stream, for example, only 1/10 / U can be large, the exhaust gases can also contain a considerable number of particles, with sizes of about 300 to 1000 or more Mioron "

One-piece catalysts with 400 individual flow channels per 6.45 cm are introduced for the treatment of vehicle exhaust gases, and such catalysts are used with 600 flow channels per 6.45 ^cm / s. One-piece catalysts, particularly one-piece metal catalysts having 1200 or more channels per 6.45 cm, may eventually become available for commercial use. Currently v / erden to. Treating single-barreled catalysts with at least 260 flow channels per 6 _S 45 cm, and a single cross-sectional opening of a one-piece catalyst with 600 flows.

2 2

The channel widths per 6.45 cm is about 0.0858 cm, where the cross section of the channel is essentially square and its sides each have longitudinal dimensions of about 0.927 mm or »927 / U. The corresponding length of a side of an open single flow channel from a

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lumpy catalyst with 400 channels per 6.45 cm is about 1135 / U, and that of a one-piece catalytic. Thus, it is apparent that in the case of using the above-described one-piece catalysts for the treatment of gases containing particulate solids, at least a ^1J- part of the particulate matter will be so large that they can not enter or pass through these flow channels, and if the particulate matter is present in large quantities in the gases, this will lead to operating difficulties'. The present invention solves these problems »

The particles may be of organic or inorganic or both organic and inorganic nature. At least the organic proportions of some of these solid particles are apparently subject to partial or complete oxidation in the first one-piece catalyst of the invention having the larger flow channels, the extent of such combustion and / or mechanical reduction due to contact with the first catalyst is sufficient to reduce the larger particles so that their passage through the smaller flow channels, which are arranged downstream of the one-piece catalysts, is without that unwanted operating difficulties of a chemical or physical nature occur *. The extent of one of. It is difficult, if not impossible, to give similar ^1J particle reductions in numerical values because the particles in the subsequently arranged one-piece catalyst bodies

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may be subject to a further reduction "Accordingly provide the sizes of any solids remaining in the cables led and exiting gases, not necessarily an indication of the usmaß the reduction _f that occurs in the first catalyst, - ^ ie amount of larger solid particles in the feed gas , which may cause difficulties in the subsequently arranged unitary catalyst body with the smaller flow channels, may be relatively small, and yet clogging and other problems may occur, at least over a long period of time, unless the one-piece catalyst system of the present invention is used. Almost any amount of solid particles of sufficient size can

I.

become a problem when the gas is first introduced into one-piece catalysts with narrower flow channels. "

According to the invention, the oxidation reactions that take place in a given catalytic zone, whether it is the first or a subsequent, downstream catalytic zone, are not sufficient to produce temperatures that damage the catalyst. The temperatures reached in a catalytic zone at least in part by the temperature of the catalyst zone gases supplied and by taking place in the in the zone ^v erbrennungsreaktionen recirculating temperature rise determined "Among the factors that influence the combustion reactions and the temperature increase resulting belong to the ^ü ehalt the gases of combustible ingredients., the amount of standing for combustion available free oxygen, the space tr öntungsge "*

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the viscosity of the gases through the catalyst and the level of catalytic activity per unit area of the catalyst. · '

By way of example, the factors affecting the extent of combustion in a catalyst zone will be explained with reference to the first catalyst zone; however, further downstream catalyst zones may operate in substantially the same manner in accordance with the invention. A possible operating state of the engine is z, B ₆ of the idle _$ wherein the result is a relatively small volume of -Auspuffgasen * The relatively low volumetric • flow velocity can be a substantial cooling of the -Auspuffgase before its ^A uftreffen on the catalyst in the first catalyst zone allow. However, this cooling is insufficient to lower the catalyst temperatures below those which activated the catalyst for the oxidation reaction. As a result of the reduced flow rate through the catalyst, a large proportion of the combustible constituents contained in the uspuff gases can be reacted; however, since the amount of gas treated is small and the heat loss from the catalyst is significant, the increase in the temperature is not sufficient to produce temperatures that could damage the catalyst. When the engine is running fast, the volumetric flow velocity is exhaust gases much higher than at idle, and the temperature drops "between the motor and the first catalyst zone generally less sharply. the ^ aumströnmngsgeschwindigkeit through the catalyst is much higher, and therefore, the catalyst can bring about no proportional greater degree of combustion, _e H",

2 20 175 -27- 20.10.1980

AP ϊ ¹ 02 Β / 220 175 57 317/11

the amount of catalyst used is not enough j to complete combustion ^ - ^{he 111} "bring tl ⁰ ^ clen catalyst flowing through combustible materials Perner act the additional gases hinaurchströmen by the catalyst, without participating in the combustion reactions in the catalyst zone, as a heat reservoir. the heat generated by the oxidation in the catalyst zone ", accordingly, the temperature in the first catalyst zone remains below those temperatures that could damage the catalyst, - the misfire or flushing of the cylinder will result in higher concentrations of combustibles, especially hydrocarbons. however, with the oxygen in the catalyst zone, the temperatures reached in the catalyst zone are in view of the low temperature of the gases flowing through the catalyst zone and the insufficient amount of catalyst for complete conversion of the combustibles not harmful to the catalyst,

Often, two-stroke internal combustion engines with stoichiometric proportions of air, to fuel for theoretically complete combustion of the fuel to carbon dioxide and water or on the fuel-rich S g _e of the stoichiometric ratio described "In this case, the lack of toffe for complete combustion of the combustible ° In the exhaust gases, sufficient free oxygen may additionally help to maintain adequate temperature increases in the catalyst zone. "To enhance the combustion of carbon monoxide and hydrocarbons" in the exhaust gases or other oxidizable materials which may be used in accordance with the invention, gases containing oxygen may be left behind, for example the first

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Catalyst zone are added to the oxidation system. In general, in the treatment of gases in the invention, sufficient free oxygen is available for the subsequent complete combustion of the stoichiometric oxidizable materials contained therein into carbon dioxide and water, and an excess of at least about 0.6 vol. », generally about 0.6 to 3 ^" o! e ~ $, oxygen of free ^D provided over that amount t that is required on a stoichiometric basis for complete combustion "Iiach of treatment according to the invention of the gases often contain less as about 0.02, preferably less than about, 0.005 mole percent carbon monoxide and less than about 0.010, preferably less than about 0.002 mole percent hydrocarbons

Since it, nfahren especially when ^ when the engine is still cold can lead to a significant cooling of the exhaust gases of the combustion source prior to the G _a se catalyst according to the invention sys tem reach 'of the first catalyst is preferably relatively close to the verb' arranged so that the exhaust gases, when they hit the first catalyst, have such high temperatures that the catalyst, when it is cold, is heated rapidly to temperatures at which it is catalytically active. In general, the first catalyst zone is in the treatment of exhaust gases or exhaust gases in such a location that the coming into contact with the catalyst gases under the operating conditions expected during operation of the engine to temperatures above about 250 ⁰ C, preferably temperatures of about 300 to GOO ⁰ C, are «'Man

2 20 I 75 ' ² ^ . 10/20/1980

AP F 02 B / 220 57 317/11

may also use additional means to achieve sufficiently high temperatures in the first zone for the catalyst to achieve suitable catalytic activity; z _e B _e can make use of the electric heater, the ignition and the combustion of additional thermal uel before the first catalyst zone and the like. In general, these agents are, however, because of the complexity that they grant the treatment system for the ^A uspuffgase not applied when temperatures have been reached, in which catalytically ^ activity achieved, the catalyst is effected in the first catalyst zone oxidation of the combustible components in the Gases to water and carbon oxides, especially carbon dioxide,

However, the extent of oxidation in the first catalyst zone of the present invention is insufficient in the wide range of operating conditions that can occur in practice to produce temperatures in this zone which could damage the catalyst. "Generally, if more than one catalyst zone is achieved In the first catalyst zone, a combustion of about 5 to 7%, preferably about 15 to 50%, of the combustible substances, ie carbon monoxide, hydrogen, hydrocarbons and the like, in the catalyst zone is used formed by one part of the system in which a catalyst is used to accelerate the oxidation of at least one component of the feed gas. This zone may have one or more catalyst bodies, and if more than one is present, they may be in contact or spaced apart. If a reactant, such as oxygen, is fuel

> -30-. · '20,10,1980

AP ϊ ¹ 02 Β / 220 175 57 317/11

or other reactive materials, the gaseous ^ trom zwischen'den catalyst structures is supplied, such addition points form separate Katalysatorzorten, one before and one after the place of addition "uf similar ^ else, if the gas flow a significant temperature change is subject to, for example, at least about 50 ⁰ C between the catalyst assemblies, the catalysts are considered before and after the location of the temperature change as arranged in two different catalyst zones, regardless of whether the temperature change, for example cooling, takes place by direct or indirect heat exchange,

The increase in the temperature of the gases in the first catalyst zone due to the oxidation occurring therein is often at least about 50 G, but not enough to produce temperatures in the first catalyst zone which are detrimental to the catalyst in the treatment of exhaust gases or exhaust gases is less than about 500 C, and often in the range of, for example, about 50 to 300 C. If more than one catalyst zone is used, the highest temperature of the effluent from the first catalyst zone exhaust gases is less than about 800 C. and, z ', B, in the range of "about 400 to 800 ⁰ C, preferably from about 450 to 650 ⁰ C, the-peak temperature in the first catalyst zone lower than those temperatures that may be detrimental to the catalyst, -because in The first catalyst zone does not contain enough catalyst to ensure complete combustion of the flammable recyclables bring the exhaust gases, and possibly because not enough oxygen for the complete combustion of the combustible value substances in the exhaust gases z-ur made available

2 20 1/5 - ³¹ ~ 20.10.1380-

57 317V 11 AP 1 < ¹ 02 B / 220

Advantageously, the catalyst in the first catalyst zone has a relatively small volume which facilitates heating to catalytic activity temperatures at start-up.

Catalytic systems for burning suitable oxidizable materials which serve as primary energy sources are known and can be adapted to the practice of the present invention. For example, fairlead radiation systems are disclosed in US Pat. Nos. 3,441,359 and 3,191,659. "Catalytic" combustion systems for indirect heat exchange purposes are described in US Pat. Nos. 3,914,090 and 3,982,879, while US Pat. No. 3,928,961 discloses The use of single or multiple catalytic combustion zones for the oxidation of carbonaceous fuels under essentially adiabatic conditions for generating power is described as having an adiabatic one when such fuels are burned with a stoichiometric amount of air at the combustion inlet temperature ^ lamb temperature of at least about 1816 ⁰ C, the operating temperatures of the catalyst in the last-mentioned systems may employ typically about 927 ° C, amounted to 1760 ⁰ C, preferably about 1093 ⁰ G to about 1649 ⁰ C, If according to the invention, solid particles containing oxidizable materials as ^ peisegaö for the various above e In the case of systems of the invention, the first catalyst which comes into contact with the gas in the catalyst zone will be a one-piece catalyst with relatively large flow channels, while a subsequently arranged catalyst in this or in another catalyst zone will have a larger number of smaller ones

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Flow channels ,. as described above, »

^ eim ³ peration of the various - ^ usfUhrungsformen the invention, the temperature of the catalyst in the first catalyst zone is preferably maintained so high that the formation of deposits on the catalyst, if it ever comes to neglect. In the treatment of Kohlenstoff.enthaltenden particles and white aerosol containing ^A uspuffgasen, for example, two-stroke engines, the catalyst temperature should lie with the Setrieb above 300 C and preferably above about 500 C to limit the formation of deposits to a minimum, "When • In two-cycle engines, the exhaust gases may contact the catalyst in a pulsatile manner, and the hot exhaust gases from the catalytic combustion may even be sucked back into the first catalyst zone. The desired temperatures can be maintained in the catalyst zone between the intermittent collisions of the exhaust gases by further catalytic combustion of the exhaust gases

combustible materials still remain in the hot combustion gases ,, which can be sucked back into the catalyst

When using systems with more than one catalyst zone, the gases flowing out of the first catalyst zone contain flammable recyclables, namely unburned carbon monoxide and unburned hydrocarbons, at least under most operating conditions of the engine. In general, the relative amount of unburned matter in the exhaust gas depends on the first one. Catalyst zone from the volume

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trischen flow velocity of the gases. Within a range of operating conditions, α, β, β-gases from the first catalyst zone contain carbon monoxide and, usually, hydrocarbons in amounts of, for example, at least about 0.1, often about 1 to 4, VOl "- / 5 carbon monoxide, and at least about 0.02, often about 0.02 to 0.8, vol. · - /? ' Hydrocarbons »The gases flowing out of the first catalyst zone are cooled, eg. B ₀ by passing them through it by a · "cooling zone the first Katal5 ^r sator zone with a second catalyst zone verbindete ¹¹ IXTOh the cooling is so far reduced, the temperature of the exhaust gases, · that in the second catalyst zone, a combustion can take place without that too high temperatures occur that could be detrimental to the catalyst contained in them «

The cooling of the exhaust gases can be done primarily by indirect heat exchange with the environment or by radiathe _e The speed and extent of the cooling therefore depend on the gas flow through the cooling zone, the temperatures of the gases, the temperature of the environment and the surface of the cooling zone from. Sine cooling of the exhaust gases from the first catalyst zone, by local cooler gases, for example air, achieved * The addition of air may also be used 'to ensure urn that the exhaust gases sufficient free oxygen and, the complete combustion of the combustible ^ö toffe contain, ^v orteilhafterweise the air between the ersten'und the second catalyst zone is added ».

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In general, the temperature drop between the first and second catalyst zones is not so great that the second catalyst is not maintained at or near a temperature sufficient to initiate and maintain the catalytic combustion. In the treatment of engine exhaust gases, the temperature drop of the gases between the first and the second catalyst zone is often, especially at low engine speeds, at least about 50 ⁰ C, for example about 50 to 400 ⁰ C, often about 150 to 350 ⁰ C, and by The gases flowing through the second catalyst zone are generally cooled to temperatures ranging from about 300 to 600 ^° C, preferably from about 350 to 550 ^° C.

In one embodiment of the invention, according to which the gases are withdrawn from the system downstream of the second catalyst zone, the second catalyst advantageously has a sufficient surface area and activity as desired

To bring about a reduction in the content of oxidisable materials in the gases within the largest part of the range of working conditions to be expected. In general, sufficient combustion may take place in the first catalyst zone and the gases exiting from this zone are sufficiently cooled so that no combustion takes place at the combustion taking place in the second catalyst zone where the catalyst could be damaged even if the gases contain relatively large quantities of flammable materials, for example, when an engine is the source of the supplied gases and misfires, under conditions of reduced fuel flow

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Thus, the temperature rise of the gases flowing through the second catalyst zone may vary greatly under different operating conditions of the engine second catalyst zone flowing 'gases at least about 25 ⁰ C, preferably at least about., 50 ^Q C _f and in the treatment of exhaust gases often about 25 to 250 ⁰ Cj _1, preferably about 50 to 200 ⁰ C,% e maximum temperatures of in the second catalyst zone gases obtained, in the treatment of exhaust gases, in general, below about 900 0 and often in the range of about 400 to 900 ⁰ C, the catalyst in the second catalyst zone is preferably heated to temperatures of at least about 450 ⁰ Cj preferably of at least " about 550 ⁰ C, held to the deposition of undesirable components on the To minimize the catalyst surface area and to let the catalytic combustion proceed »

When multiple downstream catalyst zones are used which adjoin a first catalyst zone, the second catalyst zone generally does not contain enough catalyst to cause such high levels of oxidation to reach high temperatures at which the catalyst could suffer damage. In other respects, such as with respect to the maximum temperature of the gases in the second catalyst zone, the off-axis of the catalyst zones after the second catalyst zone is similar to that in which the gases are behind the catalyst. second catalyst zone from the system, to be deducted from this second cat

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AP 3? 02 B / 220 175 57 317/11

Lysatorzone preferably joins a cooling zone in which the gases are cooled before they hit the catalyst of the next catalyst zone. The cooling may be carried out in substantially the same manner as that between the first and second catalyst zones. However, the extent of the cooling can often be somewhat less, for example be about 100 to 300 ⁰ O, the temperature of the downstream catalyst in the broad range .of working conditions of the engine, must be expected that, to be able to hold more easily sufficiently high to minimize the formation of deposits on the catalyst surface and to keep the catalyst at or near the catalytic activity efficiencies «

According to a further feature of the invention, the catalytic treatment of the gases of the internal combustion engine can also serve to reduce the content of the gases to oxides of nitrogen. When the exhaust gases contain a .for the complete combustion of carbon monoxide and hydrocarbons stoichiometrically insufficient amount of oxygen in addition to oxides of nitrogen, in the first catalyst zone an increased reduction of oxides of nitrogen can be carried _c The catalyst used in particular in the first catalyst zone can catalytically ^ having activity both for the oxidation of combustible material, as well as for the reduction of oxides of nitrogen, ^ ie oxidation reactions, the heat for the reduction reactions ^ available tellen _e In general, the working of two-cycle combustion engine under fuel-rich or nearly stoichiometric

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Conditions of the ratio of fuel to air see only relatively small amounts of oxides of nitrogen during combustion in the internal combustion engine. ° o may, for example the exhaust gases from two-stroke engines about 0.0 to 0.08 g of oxides of nitrogen j _e generate kilometer "

The catalysts suitable for the gas treatment according to the invention include one-part catalysts. The catalysts comprise one or more individual components, in particular a platinum group component, as catalytic promoter in combination with a heat-resistant oxide carrier of high specific surface area, which forms the skeletal structure ^{1 of} the one-piece catalyst forms or set down on this is _e, depending on the catalytically active metal components in your catalyst and the conditions of their use, the catalysts can be used for simultaneously catalysing oxidation and ^ edulctionsreaktionen "ο the catalysts can be used to determine the oxidation of hydrocarbons or carbon monoxide and at the same time the reduction of oxides of nitrogen to less harmful substances such as carbon dioxide, S - [; j; _c ) _C30 tff and V / asser, to favor.

catalytically active metal component of the catalysts may comprise one or more metals in elemental form or in combination, z * B _c in - ^ orm of alloys, salts, oxides, and the like, there are "pie metals are generally Schwermetaile or transition metals of Groups III to VIII of the periodic table with atomic weights of at least about 45 °. These metals include z, B ₆ the metallic metals,

5 ~ ³⁸ "20.10.1980

AP * '02 B / 220 175 57 317/11

such as nickel and cobalt, the metals of groups VB 'and VIB, for example vanadium, chromium, molybdenum and tungsten, copper,. Manganese, Rhenium, and Combinations of Such Metals Preferably, one or more platinum group metals are present. Among the useful platinum group metals include, for example platinum, ruthenium, palladium and rhodium as well as .Gemische or alloys of such metals, such as platinum-palladium, and _e. Plat in rhodium, '·'

The metal promoter generally quantitatively forms a minor amount of the composite catalyst, based on the total weight of the promoter metal and the high surface area, heat resistant oxide support, and this amount is sufficient to provide the desired catalytic effect of using the catalyst. ^ hese amounts may depend on the choice of metal and the intended ^v iNTENDED USE of the catalyst and amount by weight is generally at least about 0.01, -%, based on the total amount of promoter metal and 'carrier of high specific surface area, but these amounts can also to about 30 or 40 % or more, and are preferably in the range of about 1 to 20%. In the case of base metals, amounts are often at least about 2%. In the case of all platinum group metals, the amounts do not substantially exceed about 5% by weight, based on the total amount of promoter metal and high specific surface area, in this case the amount can be a << B, about 0.01 to 4% %, respectively, and is preferably about 0.05 "to 2%, W _e nn the catalyst contains more platinum metal-le, these can, for example, predominantly of platinum and a lower proportion of other metals of the platinum oder'mehreren

2 20175 ~ 39 "" 20.10.1980 "

AP Ε »02 B / 220 175 57 317/11

For example, this component of the catalyst may comprise about 55% to 95% by weight of platinum and about 5% to 45% by weight of palladium or rhodium, based on the total weight of the platinum metals, the amounts of the catalytic promoter metals, whether they are base metals or precious metals, are given here on the basis of the metals, regardless of their form *

Catalysts particularly suitable for systems in which oxidation and reduction are to be carried out simultaneously, for example to reduce oxides of nitrogen and at the same time to oxidize carbon monoxide and hydrocarbons which may be present in the system, comprise a platinum group metal and one or more base metals which may be selected from the above metals, and may in particular contain a metal of the iron group, such as nickel, for example in the metal oxides, Y / ie nickel oxide. The amount of platinum group metal may be as above for example, about 0.01 to 4 % _t, preferably about 0.05 to 1.5 or 2 % _t , while the base metal is often present in greater amounts than the platinum metal, eg in amounts of at least about 2 %. until about 20 % _{t is} present "These quantities also refer to the total weight of promoter metal and carrier of high specific surface area"

The integral catalysts may be coated on the surfaces of its channels with alumina them against the poisoning Wirkimg of different substances, such as biei ₉ zinc, other metals, sulfur, - phosphorus and derglei-

2 207

AP F 02 Β / 220 175 "57 317/11

to Chen, protect "Often, the amount of the 0ber ~ area-coated alumina (based on AIPO ^) a geringen.Anteil, z" B, about 10 to 100% _s of the total weight of catalytic promoter metal and support of high specific surface , and preferably this amount is about 20 to 75 % and affects the catalyst, if any at all, only insignificantly. The coated onto the surface of alumina contains catalytically active ^A luminiumoxid or as starting material for serving hydrated aluminum oxide as essential ingredients ^ ti activated alumina has a high specific surface area, for example, at least -about

25 "preferably at least about 100 in / g, as determined by the BET method, and is generally referred to as catalytically active. The active aluminas include representatives of the ¹ S -Aluminiumoxidgruppe, such as fr- and v ^ · alumina, in the egensatz The relatively inactive low surface area alpha alumina. The surface applied materials may be calcined or activated alumina or hydrated alumina, which is converted to active alumina by calcining or using the catalyst at high temperatures, such as ζ * Β _β amorphous hydrated alumina, alumina monohydrate, alumina trihydrate, or mixtures thereof "These aluminas can-metal oxides, small amounts of other components such as rare Erdme-, z _e B contain ₀ Geroxid, silica and the like," Preferably, the surface to be applied to the nte material predominantly ^A Made of alumina, based on the basis of pesticides. In particular, should

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AP Ii ¹ 02 Β / 220 175 57 317/11

the amount of the alumina betragene If other ingredients are added to the catalyst is at least about 75% of the total weight of the Peststoffe after coated on the surface of alumina, they are preferably substantially free of catalytically active metal components such as metals free of catalytically active metal components such as metals the platinum group or other promoters, which have a higher catalytic activity than the alumina applied to the surface »

The high surface area support with which the promoter metal can be combined in the catalysts according to the invention comprises one or more refractory oxides. These oxides include z, B "silica and metal oxides such as alumina including the mixed oxides such as ^ iliciumdioxid-alumina, aluminosilicates which may be amorphous or crystalline, like alumina-zirconia, alumina ~ chromium oxide, aluminum · »cerium oxide and, preferably, the carrier PROPORTION ^A predominantly of alumina, wozu'die representative of the fir -Aluminiumoxidgruppe the activated Aluminum oxides, vd.e Qr «· or r ^ -Aluminiumoxid belong. The carriers present in the catalysts of the invention in admixture with catalytically active metal component are often referred to as being in catalytically active permeant, but this activity is of a lower order than that of the catalytically active metal components the major part of the total weight of support and catalytically active metal, and the specific surface area of the support is

> -42- 20.10.1980

AP F 02 B / 220 57 317/11

usually at least about 25 m / g as determined by the BET

Method, and preferably at least about 100 m / g.

 The catalyst bodies according to the invention comprise a one-piece base support which is relatively catalytically inert when compared to the support of high surface area deposited thereon, if any. In these cases, the circular support generally has a considerably lower specific surface area than the vehicle that is applied to him. Thus, the base support can have a total specific surface area of

less than about 5 or 10 m / g _t particularly less than about 1 m / g, as determined by the BET method, have © 'The base support may be in lumpy' present -Peilchenform and is preferably in monolithic (one-piece) ^ orm, z. B ₀ as honeycomb body _β The high specific surface area support material is generally distributed over the surface of the base support or most of it as a coating, and usually, the high specific surface area support material in the catalysts is less in amount Weight of the relatively inert base support, z. B ₆ in amounts of about 5 to 25% by weight, preferably of about 10 to 20% by weight, in front of «

The relatively inert base supports of the catalysts according to the invention can be made of various materials, but are preferably predominantly composed of one or more refractory oxides or other ceramics or metals. The preferred circular supports are cordierite, orordierite c-alumina _f

2 20 1 "^ ^ -43- 20.10" 1980

'. AP P 02 B / 220

57 317/11

Silicon nitride, zircon mullite, spodumene, alumina "· ^ iliciumdioxid ~ Magnej; siumoxid or zirconium silicate" Examples of other heat-resistant ceramic materials, aie instead of "preferred G _rU ndträgerwerkstoffe used v / can ground ^include illiraanit _t magnesium silicates, zirconium, _Petalitos? , QD-alumina and aluminosilicates · Suitable metals are, in general, oxidation and heat-resistant steels "for example, v / ground various metals _s available under the trade name Kanthal and Fecralloy commercially for the production of the metal carrier from corrugated sheets of the metal tubular to a * 'orm rolled up is used »The basic carrier can

Although made of glass ceramic, but is preferably unglazed, and can be present in substantially entirely crystalline ^ orm and marked inbettungsmassen by the IJichtvorhandensein nennens ™ slipped amounts of glassy or amorphous ^, such as "B" in porcelain * Further, the ^A may TRUCTURE in contrast to the non-porous porcelain, the ₀ B _e for spark plugs .. for electrical purposes, Z: is used and a relatively low ¹ accessible porosity has j considerable accessible porosity have "the base support may be Z ₀ B _e a water pore volume of at least about The one-part catalyst body may have a total specific surface area in excess of 10 m per gram, and in particular the catalytic promoter metals may be present in them be precipitated without the use of -C rag em with high specific upper although the latter may also be present "

) -44-. "20.10.1980

   '. AP P02 B / 220 57 317/11

The one-piece ^G round carriers of the catalysts according to the invention are penetrated in each individual piece of the base carrier by a plurality of channels. Die.Kanäle are open to fluid flow and therefore do not uslaß blocked or shut off against the flow from an inlet to a separate ^A, and accordingly, the channels not only surface pores The channels are, in general are rather large compared to the GRESSE of the surface pores, so that the fluids passing through them do not undergo excessive pressure drop. The integral catalyst backbones have a uniform macrostructure framework structure with a minimum overall cross-sectional dimension generally perpendicular to the seal of fluid flow through the channels of, for example, at least about 2 cm, Zt B ₀ in honeycomb form, and have S-flow durations of at least about 10 mm, preferably at least about 20 mm.

The flow channels of the one-piece base beams may be thin-walled channels providing a relatively large surface area. The channels may have different cross-sectional shapes and sizes. They may be in cross section e.g. triangular, trapezoidal, rectangular, polygonal (with more than four sides), square, sinusoidal, oval or circular, such that cross-sections through the base support form a recurring pattern, which may be referred to as a honeycomb, corrugated or lattice structure; On the opposite sides of the structure are the inlets and outlets of the flow channels formed by the cross sections of the channels. The walls of the cellular channels are usually of sufficient thickness to form a unitary body. to obtain sufficient strength

I »45- '' 20.10.1980

•. AP P 02 B / 220 57 317/11

Usually, the ^w all thickness ranging from about 0.05 "to 0.64 now. In this ^w all thickness, the structures about 8 to 186 or more gas inlet openings for the flow channels per cm cross-section and a corresponding number of gas flow channels, preferably about 9, 3-93 gas inlets and flow channels per cm, included. the ^S hare of the open area at the cross section can be more than about 50 or 60% of the total amount «size and dimensions of the uniform heat-resistant base support stand according to the invention can vary." The basic support is monolithic or monolithic in the sense that a substantially continuous, preferably predominant, or virtually all, of its cross-section consists of a coherent framework or unit. " In general, such a unit can have a cross-sectional area of at least

2

at least about 10 cm, preferably at least about 13 cm.

According to the invention, the one-piece catalyst in the first catalyst zone has a first one-piece catalyst body with relatively large flow channels, that is

less gas flow channels per cm surface area of the face of the catalyst, compared with the flow channels in a one-piece catalyst body arranged thereafter. a plurality of catalyst bodies arranged one after the other with respect to the direction of gas flow. The first catalyst body may, preferably, be less than about 150, often

have about 50 to 100-Strönrungskanäle per-6,54 cm. The subsequently arranged catalyst body can have at least 150, often at least 200, flow passages per 6.54 cm 2 transverse flow.

i -46- 20.10.1980

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The number of flow channels in the downstream catalyst body may, for example, be up to about 300 or 400 or more. The number of flow channels in the downstream catalyst body may be substantially greater than that of the flow channels of a downstream catalyst body

The individual flow channels in the downstream catalyst body preferably have an open cross-section which is not more than about 70 %, preferably about 5 to 60 %, of the open cross-section of the individual flow channels of the first body. These first and downstream catalyst bodies may be located in different catalyst zones, but preferably adjacent to the same catalyst zone. In the latter case these catalyst bodies may form an integral body or may be in contact with each other, or they may be spaced apart, but not by such distances separated, that a considerable cooling of the gases takes place in between, otherwise the downstream catalyst would have to be considered as arranged in a separate zone. The catalysts are arranged so that the gases pass first through the upstream catalyst body, bevo they pass through the subsequently arranged catalyst body. The volume ratio of the first catalyst body to the entire first body and said downstream catalyst body may vary within wide limits, with the first catalyst body often constituting about 10 to 90% by volume of the total volume Catalyst bodies according to the invention are used for the treatment of gases, for example of exhaust gases of an engine.

2 2 0 17 5 ~ ⁴⁷ ~ 20.10.1980

APP 02 B / 220 175 57 317/11

they are preferably used at least in the first catalyst zone «,.

From the above discussion, the following relationship between the opening cross-section and the number of flow channels at predetermined cross-sections of the integral catalyst body _p results, for example, when a first

Catalyst body · has a cross section of about 12 ₅ 9 cm, and the open cross section is about 70. $ of the total cross section, it results in an open cross section

2 2

of about 9 cm per unit of 13 cm. Accordingly, the flow channel cross-section in a first catalyst body, in which the number of flow channels from about 50 to

2 2

Similarly, the flow channel cross-section in a second catalyst body may generally be at least about 200 to about 300 or 400 channels per 6.45 cm "Cross section are present in a range of

about 0 _s 0226 and 0 _$ 0116 era lie. Of course, any suitable configuration of channels may be used as long as the catalyst has the desired open cross-sectional area.

Flow channels of this or other size may be used as long as the relationship between the open cross-sectional area of the larger channels in the first catalyst body and the open cross-sectional area of the

In order to prevent clogging of the channels while maintaining a satisfactory degree of conversion, the smaller and smaller channels in the post-catalyst body can co-operate.

/ 5 -48- 20.10o 1980 ·

'AP F 02/220 175 57 317/11

Durability of the catalyst, when exposed to the gases to be treated, may be limited by the blockage of the channels. Carbonaceous materials may impinge on the catalyst inlet face and grow to a larger volume thereby potentially clogging some of the channels. "As explained above, to obviate this problem, a one-piece catalyst body having large channel openings at the inlet face is provided In this structure configuration, flakes of carbonaceous material in the exhaust gases may be broken when they impact the face of the catalyst, and the smaller particles formed thereby may pass through the smaller catalyst channels »

Exemplary embodiment

The invention will be explained in more detail below with reference to an example. In the appended drawing:

Figure 1 is a schematic representation of a device according to the invention with two catalyst zones;

Fig. ^{1 shows} a schematic representation of a device according to the invention with two catalyst zones and an additional air supply between the first and second catalyst zones;

Pig is a schematic representation of a device according to the invention with two catalyst zones, in

2 20 I / $. "49- 20.1 Q. 1,980

APP 02 B / 220 175 57 317/11

  *

The first catalyst zone having a first one-piece catalyst and a second downstream one-piece catalyst, the flow channels in the first one-piece catalyst having a larger open cross section than the flow channels in the downstream one-piece catalyst

In the drawings, the direction of gas flow through the device is indicated by arrows (not numbered). The reference numeral 10 denotes the exhaust port of the exhaust pipe of a two-stroke internal combustion engine. The exhaust gases of the internal combustion engine flow from the exhaust port through the connecting line 12 to. The first catalyst zone 14 includes a catalyst 16 disposed therein. The gases exit the first catalyst zone 14 and flow through a cooling zone or conduit 18 where they are cooled to a second catalyst zone 20 in which the catalyst 22 is disposed the second catalyst zone 20 withdraws the gases through line 24 and can be vented to the atmosphere, fed to a muffler or the like,

According to Fig. 2, an air supply line 26 is provided to supply air to the gases in the cooling zone 18 on their way to the second catalyst zone 20. The air flow rate to the cooling zone 18 is controlled by the control member 28, which is an adjustable volumetric pump ! ' Flow rate or the like may be regulated. This control element 28 in turn is by

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The feeler 30 may be in communication with at least one of the carburettors of the engine to respond to fuel-rich or fuel-lean conditions, to the ignition system or drive mechanism of the engine, and thus to engine speed and the flow rate of the exhaust gases, to a temperature sensor arranged in front of or behind the first catalyst zone 14, to a carbon monoxide and / or hydrocarbon sensor arranged in front of or behind the first catalyst zone 14, or to an acid sensor arranged in front of or behind the first catalyst zone 14 this ^w ay, the additional air to the A _US p _U ffgasen be added in such amounts as are required to puffgasbehandlung the A _us "so carried out that sufficient S _Auer toff for the combustion of the · combustible contaminants in the exhaust gases available stands, and / or that the Gases are sufficiently cooled before being passed in a catalyst zone.

According to Pig * 3, the first catalyst zone 14 contains two integral catalysts 16A and 16B. Relative to the direction of gas flow through the apparatus, first the first unitary catalyst 16A is located and immediately adjacent thereto the second or subsequent one-piece catalyst 16B, ie individual flow channels in the first integral catalyst 16A have a substantially greater open cross-section than the individual ^ tröraungskanäle of the second or downstream integral catalyst 16B _¥ the remainder of the apparatus of Pig. 3 is identical to &

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'jenigen of Figure 1, wherein all corresponding parts with the same -. are provided ezugsz calibrate ^ and therefore require no v / Eiteren explanation, "In another ^A na führungsfοπή, .the in the drawings is not illustrated, the arranged first piece Catalyst 16A may be spaced slightly from downstream one-piece catalyst 16B (but not so much that substantial cooling of the gases occurs between these catalyst bodies) both contained in the first catalyst zone 14. Two integral catalysts comprising the one-piece catalysts 16A and 16B are similar or "same, can be arranged in the second catalyst zone and just as well in the first catalyst zone 14 o

Invention will now be described by way of example in which all parts and pros are used in terms of volume unless otherwise indicated *

Yamaha motorcycle with a 350 ecm two-cylinder two-stroke engine is provided on one of its exhaust pipes with an exhaust gas treatment apparatus similar to that of Fig. 2, except that both catalyst zones contain two integral catalyst bodies as in the first catalyst zone Embodiment of Fig. 3. In order to simplify the test in an experimental sense, the exhaust gas from the second exhaust pipe at the. Test not considered. The values given below have been doubled to approximate the values which would occur when the total exhaust gases from this engine are used.

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The air supply is manually controlled so that at motorcycle speeds less than 48 km / h, 4,2.5 1 air / min and at motorcycle speeds in excess of 48 km / h 113 1 air / min are supplied. The air is introduced into the exhaust gases immediately downstream of the rear face of the first catalyst The first catalyst is located 38 cm behind the exit port of the exhaust line and consists of two consecutively arranged and abutting integral catalyst bodies with a total catalyst volume of 181 cm and a cross sectional area of 17 , 8 cm. The front catalyst body is 2.54 cm long and has 9.92

Openings or gas flow channels per cm on _r while the adjacent, underlying catalyst body has a length of 7 $ 62 cm and 40.3 openings per cm on v / eist »The catalyst in the second catalyst zone is formed as well as that in the first catalyst zone«, The first and second catalytic converters are interconnected by a conventional 26.7 cm long metal exhaust pipe. The exhaust gases from the second catalyst zone flow into a conventional muffler of the motorcycle. The fuel used in this example for the motorcycle is a conventional combination of a commercially available Zweitakterschmieröl 'and · gasoline with a research octane number of 91, a ^B leigehalt of about 0.0053 to 0.0066 g / l, a mean ^ö chwefelgehalt of 300 ppm and a phosphorus "content of less than 1 ppm".

The application of the method according to the invention is performed on the two-stroke motorcycle described above using a motorcycle two-wheel chassis dynamometer (Model

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Clayton) with an inertial weight of. 218 kg shown. During the test, the motorcycle is cooled by two 73.7 cm fans, one of which is arranged on each side of the front tire at an angle to the mofor. The cooling air flow corresponds to the air flow at motorcycle speeds of 40 km / h, '

The exhaust gases from the exhaust system are analyzed essentially according to the "EPA Light Duty Vehicle Emission Test Procedure" (1975-I ¹ TP) ". The duration of the test is 31 min, with the motorcycle running for 14 min under urban driving conditions ranging from idle to 56 km / h and 10% of the test time at a speed of approximately 80 km / h. During the emission test, emissions of 3.25 g of hydrocarbons per lane, 6.5 g of carbon monoxide per km and 0.02 g of nitrogen oxides per km determined * Without application of the method according to the invention, the emissions are about 11.5 g of hydrocarbons per ion, 14 δ carbon monoxide per km and'0.02 g Nitrogen oxides per lane «The maximum temperature profiles of the exhaust gas treatment system. v / ground for a travel speed of 89 "6 km / h and" determined Standtfahrtbedingungen at speeds less than 56 km / h with 89 _s 6 km / h, the temperature of the light incident on the first catalyst exhaust gases 377 ⁰ C and that of the exhaust gases of the first catalyst 765 ° 0 _e ^ ie temperature of the light incident on the second catalyst gases is 743 ⁰ O and that of the exhaust gases of the second catalyst 893 ⁰ C. Under ^s tadtfahrtbedingungen the temperature of the light incident on the first catalytic converter exhaust gases is 314 _f 5 ⁰ C, that of the exhaust gases from the first catalyst 565 ^ s that of the second

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Catalyst impinging gases -363 ⁰ C and that of the bbase of the second catalyst 588 ⁰ O,

The favorable properties of two one-piece catalyst bodies arranged one after the other and adjoining one another were confirmed by further experimental values. In this example, the one-piece catalysts used had a diameter of 5 476 cm and a total added length of 10.2 cm two regions, the first region at the inlet being a 2.54 cm long catalyst The unitary backbone of this catalyst body consisted of honeycomb cluPont-Torvex with 64 flow channels per 6.45 cm cross-section 7 $ 6 cm of the catalyst had a one-piece NGK base support with flow channels per 6.45 cm cross-section. the first catalyst piece had an open total cross-section of about 14.32 cm, the individual ^s trömungskanäle each having an open cross section of 0.058 cm * the second catalyst piece had an open Geoamtque The first and second catalyst pieces were arranged in adjacent position, so that the outlet from the first piece in direct contact with the inlet of the second piece After operation of the two-stroke engine of 28,620 km, no clogging of the channels could be observed using this catalyst.

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Although the above-described configurations or »embodiments of the catalysts of the invention in terms of. however, their use is not limited to these, rather, these catalysts can also be used in conjunction with diesel engines or other machinery or even other sources of gases, particularly, especially those described with reference to particular examples in connection with the use of two-stroke "engines" in conjunction with such ejections of carbonaceous deposits or other solids which can easily clog a one-piece catalyst The invention can also be used in other combustion systems, such as in the catalytic combustion of fuels, that is, in the Application as Primary Energy Source "In all these applications, the catalyst systems according to the invention lead to a blockage of the possible clogging of the one-piece catalysts."

In summary, the invention relates to a device for the catalytic treatment of gases containing oxidizable constituents, comprising a catalytic system having at least two integral regions, in which the first region arranged flow channels, which have a substantially larger cross-section than tliie cannula in a downstream region »

When the au treated gases teiclhenförmige materials (liquid drops and / or solids) in size contain _s that could clog the smaller .Kanäle of the downstream catalyst that lead to greater Strömungakanäle of

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One-piece arranged catalyst area to ensure that the risk of clogging is lowered to a minimum or eliminated altogether. The contact of the particulate ^SUBSTANCES with the larger flow channels serves sie.zu collapse and to enable it thereby in a position to pass through the smaller flow channels. In addition, the größeren.Strömungskanäle in the first region arranged therefore reduce the ^A usmaß the catalytic reaction and reduce a temperature increase in the first catalyst zone arranged integral.

This system can be used to 'catalytic! Treatment of gases are used which contain a sufficient amount of oxidizable components for the catalytic system to be used as the primary energy source. It may also be used to treat gases in which the oxidizable constituents are present in minor amounts, such as in the case of treating exhaust gases or exhaust gases, to reduce the amount of pollutants, for example, for treating an exhaust gas containing carbon monoxide and hydrocarbons.

In the treatment process of the present invention, the gases are first passed into a first catalyst zone containing an integral catalyst in an amount which is insufficient for complete combustion of the carbon monoxide and hydrocarbons in the gases, the first catalyst zone not reaching those temperatures be harmful to the catalyst

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may be cooled and passed into a second one-piece catalyst zone, the cooling being sufficiently great to avoid reaching temperatures in the second catalyst zone that are detrimental to the catalyst. The catalyst has at least two regions at least in the first or in the second catalyst zone, preferably in the first catalyst zone, the first region having flow channels which have a larger cross-section than the channels in a downstream region of the catalyst in this zone,

Claims (2)

2 2 0 17 5 -58 - AP F 02 B / 220 175 57 317 11 He is entitled to claim 1. A device for the catalytic treatment of gases containing flammable recyclables, according to patent 133 058 (AP F 02 B / 201 374), characterized in that it consists of a first. Catalyst body (16) for the partial combustion of the gases and for generating a catalytic combustion exhaust gas containing residual flammable recyclables and a second, behind the first catalyst body (16) arranged catalyst body (22) for receiving the in the first catalyst body (16) burned gases and for combustion thereof, for producing a combustion exhaust gas, said catalysts (16; 22) being designed so that they are not so high in the said catalyst bodies (16; 22) that they are harmful to the catalysts, the first catalyst body (16) a much , Number of flow channels with inlet and outlet ports for passing the gases, the arranged behind the second catalyst body (22) having a plurality of flow channels with inlet and outlet ports for passing the gases, and wherein the open Ouerschnittsflache the individual flow channels of the first catalyst body (16 ) is substantially larger than that of the individual flow channels of the arranged behind the second catalyst body (22). 2, device according to item 1, characterized in that the open Ouerschnittsflache of both mentioned 5 ~ 59 ~ '' 20.10.1980 AP P 02 B / 220 175 51 317/11 Catalyst bodies (16; 22) make up at least about 60 % of the total cross-contamination area » 3 »Device according to one of the items 1 or 2, characterized in that the first catalyst body (16) has about 50 to 150 flow channels per 6.45 cm in cross-sectional area. 4. Device according to item 1, characterized in that • the open cross-sectional area of the individual S-trömungs- "channel of the arranged behind the first catalyst body (16) second catalyst body (22) no more than about 70 % of the open Quersclinittsflache the individual ^ flow channels of the first catalyst body (16) " 5ο device according to item 1, characterized in that the first catalyst body (16) not more than about ο
100 Strömungskaniile per 6.45 cm ¹ "cross-sectional area and arranged behind the second catalyst body (22) has at least about 150 ³ flow channels per 6.45 cm in cross-sectional area _e 6 _e device according to point 5 _S, characterized in that the open Querersclinittsflache the-individual ^ flow channels of the arranged behind the second catalyst body (22) about 5 to 60 % of the open Queröchnittsfläche the individual ^ü flow channels of the first Ka t alysat o.rkor ρ er s (16) represents _β J-60- 20.10.1980 AP F 02 B / 220 175 57 317/11 7. Device according to one of the Punkt.5 or 6, characterized in that the second catalyst body (22) behind the first catalyst (16) and adjacent thereto is arranged and in the same exhaust treatment zone as the first catalyst body (16). 8. The device according to item 7, characterized in that the Ströiaungskanäle in the catalyst body (16; 22) by% hands are formed, which have a thickness of about 0.05 to 0.64 mm. Apparatus for the catalytic treatment of exhaust gases from an internal combustion engine, the gases containing carbon monoxide and hydrocarbons, characterized in that it consists of a first catalyst body (16A) for partially burning said gases and for producing a catalytic combustion exhaust gas containing flammable recyclables. and a second catalyst body (16B) disposed therebehind adjacent to the first catalyst body (16A) and in the same exhaust treatment zone as the first catalyst body (16A) for receiving the exhaust gases burned in the first catalyst body (16A) and generating a combustion exhaust gas it, wherein the catalysts (16Aj 16B) are designed so that in the catalyst bodies (16) A; 16B) are not so high as to be detrimental to the catalysts, the first catalyst body. (16A) about 50 bia 200 flow channels per 6 _$ 45 cm "cross-section with on" J-61- 20,10,1980 AP F 02 B / 220 57 317/11 Laß- and ^{A has} outlet openings for receiving and emitting the exhaust gases, arranged behind the second catalyst body (16 B) about 200 to 1200 flow channels per 6545 cm 'cross-sectional area with ^ inlaß- and ^il uslaß ~ openings for receiving, and discharge of the exhaust gases, the Flow channels of both the first and the behind arranged second catalyst body (16 B) have an open cross-sectional area which makes up at least about 50 % of the total cross-sectional area of the body, the flow channels are formed by walls which are about 0.05 to 0.64 mm are thick and the open cross-sectional area of the individual flow channels of the second catalyst body (Ί6Β) arranged behind it constitutes about 5 to 70 % of the open cross-sectional area of the individual flow channels of the first catalyst body (16) so as to block the flow channel e of the two catalyst bodies (16A; 16B) «, 10, device according to items 1 or 9, characterized in that behind the two said catalyst bodies (16A, 16B) another catalyst body (22) is arranged with a plurality of flow channels therethrough, and in that cooling devices (18) are provided _e Apparatus according to item 10, characterized in that the cooling devices (18) comprise means (28; 30) for introducing an oxygen-containing gas into a gas. Leit imgsvorrichtung (26) for the said gases «, -62- 20.10.1980 AP P 02 B / 220 175. 57 317/11 12. A method for the catalytic treatment of gases containing combustible ^Y 'ert materials and therein suspended solid particles, characterized by bringing the said ^ ase mrt a ersten'Katalysatorkörper in contact in order to burn these gases in part and a first V b _{he re} nnungsabgas to generate containing combustible residual valuable substances, gases treated in the first catalyst body with a. ..zweiten catalyst body which is positioned with respect to the first Kafalysatorkörper behind and - ^ ufnähme the burnt in the first catalyst body gas and used to generate a ^v erbrennungsabgases, bringing into contact, wherein the catalysts are designed so that in the said percussion bodies are not so high that. they are detrimental to the catalysts, the first catalyst body having a plurality of flow channels with Dinlaß- and ^iL outlet openings for receiving the said gases and solid '''''' and the release of the burnt ash, said, arranged behind the second catalyst body a plurality of flow channels having inlet and outlet ports has to ^Recording of the burnt in said first catalyst body gases and for discharging exhaust gases, the open cross-sectional area of the individual flow channels of the first catalyst body is considerably larger than the open cross-sectional area of the individual flow channels arranged behind the second catalyst body to prevent clogging of the flow channels in said catalyst bodies and the flow channels in the second cata- arranged behind it. lysatorkörper such a small open cross-sectional area 2 201 / · 5 -63-. 20.10 '. 1980 APP 02 B / 220 175 57 317/11 that the particulates contained in the feed gas would clog the channels if the gas were first introduced into the second catalyst body. " 13 »Method according to item 12, characterized in that the open cross-sectional area of both catalyst bodies made up at least about 60 % of the total cross-sectional area 14. The method of item 13, characterized in that the first catalyst body has about 50 to 150 flow channels per 6.45 cm cross-sectional area, the second catalyst body arranged behind it has about 200 to 1200 Strömurigskanäle per 6.45 cm cross-sectional area and the open cross-sectional area of the individual Strömungskanäl 'e of the second catalyst body constituted about 5 to 70% of the open cross-sectional area of the individual flow channels of the first catalyst body 15 «A method for katalytisehen treatment of solid particles containing exhaust gases from internal combustion engines, which gases contain at least about 2 VoI _e ~ $ carbon monoxide, at least about 0.05 VoI, -55 hydrocarbons and free oxygen, characterized in that the exhaust gases in a first catalyst zone to partially burn it and to produce a first catalyst zone combustion exhaust gas containing flammable recyclables, the first catalyst zone containing such an amount of oxidation catalyst; 2 201 7 5 -64- 20.10.1980 AP P 02 B / 220 175. 57 317/11 to combust about 15 to 50% by volume of the combustible substances contained in the exhaust gases under the conditions of said partial combustion, and this amount is insufficient to produce temperatures in the first catalyst zone which are detrimental to the catalyst wherein the temperature of the first catalyst zone combustion exhaust gas about 50 to 500 ⁰ C is higher than the temperature of the guided into the first catalyst zone exhaust gases, the catalyst in der.ersten catalyst zone second from a first catalyst body having a ^v ielzahl of flow channels and, arranged behind it Catalyst body having a plurality of flow channels, the open transverse sectional area of the individual flow channels of said first catalyst body is substantially larger than the open cross-sectional area of the individual flow channels of said behind arranged zv / eiten catalyst body, which from the first Katalysatorzo ne obtained combustion exhaust gases by at least about 50 C. cooled and then passes the obtained from the first catalyst zone, the cooled combustion exhaust gases in a second catalyst zone containing an oxidation catalyst, to produce a zv / eites catalyst zone combustion exhaust gas, the temperature of the second catalyst zone combustion exhaust gas by at least about 50 ⁰ C higher as the temperature of the cooled combustion exhaust gases obtained from the first catalyst, which is not enough to produce temperatures in the second catalyst zone which are detrimental to the catalyst. 7 5 ~ ⁶ 5- 20.10.1980 AP F 02 Β / 220 175 57 317/11 I6e method according to item 15, characterized in that the combustion exhaust gas obtained from the first catalyst zone has a maximum temperature of about 400 to 800 C and. about 50 to 400 C is cooled before it is passed into the second catalyst zone. The process according to item 16, characterized in that additional air is added to the combustion exhaust gas obtained from the first catalyst zone before it is introduced into the second catalyst zone, the amount being sufficient so that an excess of free oxygen over the stoichiometric amount to Combustion of the flammable recyclables of the exhaust gases from the first catalyst zone 'required amount is obtained. 18 _e method according to the items 12 or 15 $ characterized in that the oxidation catalyst as a metal component with catalytic activity containing a metal of the platinum group The process according to item 18, characterized in that the oxidation catalyst in the first catalyst zone also contains a metal of the iron group, 20 _ö method according to the points 15 or 18, characterized in that the first catalyst body not more than about 200 Ströniungskanäle per 6. 45 cm Querschnittsflä and arranged behind the second catalyst body about .200 to. 60
surface about 200 Ströniungskanäle per 6. 45 cm cross-sectional area t < about \ 200 to.600 flow channels per 6.45 cm cross section 2 20 175 - ⁶⁶ - 20.10.1980 AP F 02 B / 220 • 57 317/11 21. A method according to item 20, characterized in that the catalyst used in the second catalyst zone consists of at least two catalyst bodies arranged one behind the other, each having flow channels therethrough, the first catalyst containing not more than about 100 flow channels per 6.45 cm and the first catalyst second catalyst body has at least about 150 flow channels per 6.45 cm cross-sectional area, 22 «Process for the catalytic treatment of solid particles containing. Exhaust gases of two-stroke internal combustion engines, characterized in that the exhaust gases are passed into a Katalysatorζone containing an oxidation catalyst for generating a catalytic combustion exhaust gas, which consists of at least two one-piece, one-piece catalyst bodies, each having a plurality of flow channels, wherein the first catalyst bodies have less than about 190 flow channels per 6.45 cm cross-sectional area and the second catalyst body arranged behind them at least about 200 flow channels per 6.45 cm cross-section, the open cross-sectional areas of said flow channels at least in both the first and the second catalyst body arranged thereabove represents about 50 % of the total cross-sectional area of the body and the open cross-sectional area of the individual flow channels in said behind said second catalyst body ge about 30 to 95 % ge is the one of the individual flow channels in the first catalyst body. , CI U 1/5 -67-. , 20.10.198.0 AP ϊ ¹ 02 Β / 220 57 317/11 23. Method according to item 22, characterized in that the first catalyst body has about 50 to 100 flow Channels per 6.45 cm cross-section! "laugh and the said second catalyst body arranged behind it about 200 Ms 1200: having. Ms 1200 flow channels per 6.45 era cross-sectional area 24β A process for the catalytic treatment of pulsating, solid particles containing two-stroke 'combustion engine exhaust gases, said gases containing at least about 2% by volume carbon monoxide and at least about 0.05% by volume hydrocarbons, characterized -4 by passing the exhaust gases into a first catalyst zone without substantial addition of free oxygen to partially combust these gases and to produce a first catalyst zone combustion exhaust containing flammable recyclables, the first catalyst zone containing such an amount of oxidation catalyst to burn about 15 to 50 % by volume of the carbon monoxide and hydrocarbons contained in the exhaust gases under the conditions of partial combustion and, in the first catalyst zone, to produce temperatures which are not detrimental to the catalyst; Catalyst zone obtained combustion exhaust about 50 to .500 ⁰ G is higher than the temperature of the first catalyst, one supplied exhaust gases, the ICa.ta3.ysator consists of at least two successively arranged, adjacent, one-piece catalyst bodies j each of which has a plurality of flow channels, the first of the two catalyst body for contact with the ^A uspuffgasen about 2 201 7.5 -68- 20.10.1980 , · APP 02 B / 220 175 57 317/11 50 to 100 ^s flow channels per 6.45 cm cross-sectional area and a second catalyst body arranged thereafter in this zone about 200 to 400 flow 2
channels per 6.45 cm cross-sectional area, the open cross-sectional area of the flow channels in both the first and the subsequent catalyst body is at least about 50 % of Gesaratquerschnittsflache of the body and dre open cross-sectional area of the individual ° flow channels in said second Kalysatorkörper about 30 to 95 % lower than that of the flow channels in the first catalyst body cooling the combustion exhaust gases obtained from the first catalyst zone by at least 50 ^° C. and then converting the combustion exhaust gases obtained from the first catalyst zone into a second catalyst zone containing an oxidation catalyst to produce a second catalyst zone combustion exhaust gas, the temperature of the second catalyst zone obtained combustion exhaust gas is at least about 25 ⁰ C higher than the temperature of the obtained from the first catalyst zone, cooled combustion exhaust gases, but this temperature is not so high
To generate temperatures in the second catalyst zone, which are detrimental to the catalyst ₀