DE2261222A1 - Catalyst for use in ic engines - contains lanthanum, cobalt, nickel and uranium - Google Patents

Abstract

Higher hydrocarbons are converted into gaseous mixts. contg. mainly CO, CH4 and/or H2, over a catalyst contg. oxides of La, Co, Ni and U, on an oxide carrier. The catalyst has high activity and long life, does not include expensive precious metals, resists rapid changes in temp., and raises the rate of reaction by about 10x. Specif. the catalyst is used in combustion engines, esp. automobile engines. The mixt. of CO, CH4 and H2, with addn. of air, is fed to the engine; this mixt. burns more rapidly and more completely in the engine than the higher hydrocarbons, thus reducing pollution.

Description

Catalytically active body addendum to patent (registration Akt.Z.

P 22 10 365.7, VPA 72/7514).

The main patent relates to a catalytically active body for conversion higher hydrocarbons, especially for conversion to carbon monoxide, methane and / or gas mixtures containing hydrogen.

The conversion of hydrocarbons into gas mixtures containing carbon monoxide, Methane and X or hydrogen, for example, is already proposed in one Process for the operation of internal combustion engines carried out (German Offenlegungsschrift 2 103 008 and German patent application Akt.Z. P 21 35 650.3). That with this procedure through the catalytic conversion of fuel and a oxygen carrier Gas-produced gas mixture that contains carbon monoxide, methane and hydrogen can, burns - in the presence of a further proportion of serving as an oxygen carrier Gas - in an internal combustion engine, for example a gasoline engine of a motor vehicle, faster and more completely than higher hydrocarbons (hydrocarbons with two or more carbon atoms, especially hydrocarbons with one carbon number greater than 4). The pollutant emissions in the exhaust gas can therefore be reduced considerably. The oxygen carrier required to convert the higher hydrocarbons can be used in the form of air. But the air can also, at least In part, the exhaust gases from the internal combustion engine replace the oxygen in particular in the form of carbon dioxide C02 and water vapor H20. The composition of the gas mixture obtained in the conversion of the higher hydrocarbons with the Catalyst temperature can be changed.

To the catalytically active bodies that are involved in such a process Find use, diverse requirements are placed. You should be one have high mechanical and thermal strength and only a low pressure loss cause. In addition, the catalytically active body should reduce the reaction rate specifically accelerate the conversion reaction to be carried out and finally they should keep their activity in both oxidizing and reducing atmospheres sustained in the long term.

The catalysts that are used in the process mentioned or in a device are used to carry out this process, but do not yet meet all of them Requirements. This applies in particular to the high requirements with regard to the Resistance to thermal shock and resistance to changing reaction conditions. It has been shown that under the reaction conditions mentioned (rapid Temperature change on the catalytic converter and alternating occurrence of oxidizing and reducing reaction conditions) nickel catalysts in their long-term activity ease up. Platinum catalysts, on the other hand, have the disadvantage that they are expensive. In addition, the natural platinum deposits are relatively small, so that the use of platinum-containing gap gas generators, such as the device part in which the conversion of hydrocarbons takes place, referred to, in motor vehicles can only be realized with difficulty in the required high numbers.

The main patent therefore has a better catalytically active body for the conversion of higher carbon dioxide, in particular for the conversion into carbon monoxide, Gas mixtures containing methane and / or hydrogen are proposed.

This catalytically active body consists of an oxidic catalyst carrier and a catalyst containing oxides of the metals lanthanum, cobalt, nickel and uranium. The catalytically active body according to the main patent points to other, known ones Catalysts have an increased service life and increased activity. About that in addition, the catalytically active body is cheap to manufacture and large in size Extensively accessible because it contains no precious metal in particular.

The oxidic catalyst support of the catalytically active body after the main patent can be aluminum oxide A1203, magnesium oxide MgO, silicon oxide SiO2, Contain zirconium oxide Zr02 or titanium oxide TiO2 as well as mixtures of such oxides. The catalyst support advantageously contains aluminum oxide, preferably «-Al20D, and Magnesium oxide, these two oxides - at least in part - being particularly advantageous in the form of a double oxide MgO. Al203 (spinel) may be present.

If the catalyst carrier contains a mixture of magnesium oxide and aluminum oxide, for example, according to a further proposal in the main patent, the content of magnesium oxide is advantageously 1 to 50% by weight and the aluminum oxide content 50 to 99% by weight, ZQ; Preferably the Kataysatorträger should 10 to 30 wt .-% magnesium oxide and 70 to Contains 90% by weight of aluminum oxide.

The main patent also includes a catalyst carrier with around 15 Wt% MgO and 85 wt% A1203 suggested.

For the production of the catalytically active proposed in the main patent Body or its catalyst carrier can be used in a process that is carried out at the same time German patent application filed with the main patent, highly porous and gas-permeable ceramic carrier, especially for catalysts, and process for its production ", Current time

P 22 10 438.7, is proposed.

To produce the catalytically active body, first an oxidic basic substance together with fillers for the production of the catalyst carrier, which volatilize at elevated temperature, placed in a mold and pressed to form a shaped body; the shaped body then undergoes a firing process subject. The catalyst support obtained is then coated with a lanthanum, Solution containing cobalt, nickel and uranium salts soaked and then dried, then the metal salts are thermally decomposed.

The catalytically active body is preferably according to the main patent Manufactured in such a way that aluminum oxide and magnesium oxide are the basic substances together with water, punching oil, graphite and / or soot and organic, thermally degradable Polymers are mixed and pressed in a compression mold to form a molded body. Of the Shaped body is then fired at a temperature between 1350 and 170 005 and the resulting catalyst support with an aqueous solution of lanthanum, Impregnated with cobalt, nickel and uranyl nitrate. Subsequently, at a temperature dried from about 1000C and finally the metal nitrates are heated by heating decomposed to about 700 to 90002.

This temperature range is advantageous because at lower Temperatures catalytically active bodies can be obtained that are hygroscopic and can therefore be changed in the air.

1) ie fillers in the form of inorganic or organic substances, those in the combustion process by combustion with gas formation again from the catalyst are removed, on the one hand have the task of creating a crumbly, plastic processing compound to produce, on the other hand, they serve to form pores in the catalyst support. In particular, graphite or carbon black, punching oil (i.e. a machine oil high purity) and organic, thermally degradable polymers can be used. Preferably are called organic polymers Polyvinyl acetal, polyvinyl alcohol, Polyglycols or cellulose derivatives, such as methyl and ethyl cellulose and methyl hydroxyethyl cellulose, used.

The firing process can - according to the main patent - at one temperature from about 1400 to 14200C, especially when using Aluminum oxide and magnesium oxide as a catalyst carrier. It becomes a catalyst carrier with high porosity, high mechanical strength and good thermal shock resistance obtain.

The object of the invention is to provide the main patent (application Akt.Z. P 22 10 365.7) proposed catalytically active body for the conversion of higher Hydrocarbons, especially for conversion into carbon monoxide, methane and / or Hydrogen-containing gas mixtures to improve further.

This is achieved according to the invention in that the catalytically active Body made of an oxidic catalyst carrier and an oxide of the metals T lanthanum, Cobalt, nickel and uranium containing catalyst consists, and that the catalyst support 23 to 27 wt% magnesium oxide, preferably about 26 wt% MgO, and 77 to 73 0 / a by weight of aluminum oxide, preferably about 74% by weight of Al 2 O 3.

It has been shown, surprisingly, that a catalytic active body with the composition mentioned has particularly beneficial effects in the catalytic conversion of higher hydrocarbons. This is especially true in terms of activity and lifespan.

The catalytically active body according to the invention contains as a catalyst - in the form of oxides - advantageously 55 to 92% by weight lanthanum, 2 to 30% by weight cobalt, 1 to 10% by weight nickel and 0.1 to 8% by weight uranium, each based on the total content of the catalyst on these metals. Preferably contains the catalyst 65 to 78 wt% lanthanum, 15 to 25 wt% cobalt, 2 to 6 wt% nickel and 1 to 2% by weight uranium.

The catalytically active body can also act as a catalyst with nickel oxide and uranium oxide doped lanthanum cobalt oxide LaCoO3 (lanthanum cobaltite). This Mixed oxide contains, based on the metal content, about 70 total lanthanum and 30% by weight Cobalt. The nickel content of such a catalyst can be 1 to 10% by weight and the uranium content is 0.1 to 8% by weight, based in each case on the total metal content of the catalyst.

However, it is particularly advantageous that the catalyst contains more lanthanum than corresponds to the stoichiometric compound lanthanum cobaltite LaCoO3. Preferably Such a catalyst contains about 70.6% by weight of lanthanum, 24.6% by weight of cobalt, S, O wt .-% nickel and 1.6 wt .-% uranium, each based on the total metal content of the catalyst.

The catalytically active body according to the invention can contain 0.1 to 13% by weight Contain catalyst, based on the weight of the catalyst support. Advantageous the catalytically active body contains 5 to 9% by weight of catalyst and preferably about 8% by weight of catalyst, based in each case on the catalyst support.

The catalyst carrier is advantageously made of a porous material. the Oxides used, Al 2 O 3 and MgO, are particularly suitable in the form of sintered ceramic material, for example in the form of a sintered stone. The porosity of the The material of the catalyst support is advantageously 20 to 60% by volume, preferably about 40 to 45 vol .- *; the material is predominantly open-pored. The porosity of the material is advantageous because it provides good heat resistance can be guaranteed. The sintered stones are preferably plate-shaped formed and they are advantageous in addition to the existing pores provided with channels arranged approximately parallel to one another.

The channels that completely penetrate the sintered stones, i.e. themselves Extending from one surface of the sintered stone to the other serve for passage the mixtures of hydrocarbons and oxygen or oxygen-containing compounds and / or the gas mixtures formed therefrom, which contain CO, CH4 and / or H2. the Use of channels provided with catalyst supports has the advantage that the Pressure loss can be kept low. The catalyst material is predominant in the porous surfaces of the catalyst carrier and in its porous areas, which surround the passage channels, arranged so that a complete implementation of hydrocarbons can be achieved. It has also been shown that the channels present in the catalyst carrier can be relatively short, i.e. that the catalyst carrier can be relatively thin if that is in the catalyst carrier entering gas mixture has a turbulent flow. In this case it is sufficient it is for example that the passage channels are about 5 to 10 mm long.

The sintered stones have about 10 to 70 channels, preferably about 40 up to 60 channels, on every square centimeter of sintered stone surface; the diameter of the channels is about 0.8 to 2.0 mm, preferably about 0.8 to 1.3 mm. The channels could also have a diameter of less than 0.8 mm per se, the lower limit however, the diameter of the channels is limited for manufacturing reasons. The number of channels per cm2 and their diameter is advantageously chosen so that both a complete conversion of the hydrocarbons and a high thermal one unqoechanical strength of the catalyst carrier is guaranteed. A sintered stone has, for example, the dimensions 46 mm x 66 mm x 14 mm and the side surface with dn dimensions 46 mm x 66 mm is with about 1200 channels with a diameter each 1.1 mm (and a length of 14 mm) provided; on every Square centimeters The largest area of the sintered stone is accordingly about 40 passage openings. Such a sintered stone weighs about 50 g, for example.

The catalyst support preferably consists of pure materials. The aluminum oxide, which is used in particular in the form of 2-Al 2 O 5, has advantageously a degree of purity> 95% by weight; an appropriate degree of purity advantageously has the magnesium oxide. The content of the starting material of the catalyst support of alkali metal oxides is expediently less than 0.2% by weight. The SiO2 content should not exceed the value of about 2%. The grain size of the aluminum oxide used is advantageously below 50 / u, preferably in the range between 2 and 4 / u.

The magnesium oxide used as the starting material is advantageous a grain size below 100 / u, preferably about 30 to 40 wt. of the magnesium oxide have a grain size in the range between 40 and 60 / u. Particularly beneficial it is when the grain size of the magnesia is larger than that of the alumina.

The catalytically active body according to the invention has for the conversion of hydrocarbon / oxygen mixtures (where the oxygen is in the form of air, Carbon dioxide, water vapor and the like. Can be present) to carbon monoxide, methane and / or Gas mixtures containing hydrogen have a high activity.

In addition, it has a long service life, which even with frequent, rapid temperature change and both when operating in oxidizing as well as reducing Atmosphere is guaranteed. The high activity of the catalytically active body can be used in a wide temperature range, for example in the range from 200 to 9000C will. With the aid of the catalytically active body according to the invention is opposite conventional catalysts increase the reaction rate by about achieved a factor of 10.

The beneficial effects of the catalytically active according to the invention Body result from its composition, i.e.

they can be due to an interaction between the catalyst support and recycled to the catalyst. The catalyst is, at least in part, into the framework of the catalyst carrier, which itself already has a certain level of activity can, built-in. For example, lanthanum oxide and nickel oxide can partially be used in a spinel lattice can be installed.

Cobalt oxide, on the other hand, is preferentially located at active centers on the surface of the catalyst carrier. As an additive to aluminum oxide, magnesium oxide has a stabilizing effect Effect.

Uranium oxide prevents the catalytically active body through thermal diffusion is inactivated. Without this substance, for example, due to a temperature gradient in the catalytically active body on one side of the catalytically active body one Form a coherent cobalt layer, which leads to inactivation. Uranium oxide also accelerates the conversion reaction to be carried out, especially during the start phase.

The production of the catalytically active body according to the invention takes place advantageously according to the following procedure. The starting materials, 73 to 77% by weight Alumina, 23 to 27 wt., - Magnesium oxide, the proportions of these two Add metal oxides to 100 ffi, water, punching oil, graphite and / or carbon black and at least an organic, thermally degradable polymer, preferably polyvinyl acetal mixed together. The mixture obtained in this way is introduced into a compression mold and pressed into a molded body. The shaped body is at a temperature between 1500 and 158000, preferably at about 156000, and the one obtained thereby Catalyst support with a solution containing lanthanum, cobalt, nickel and uranium salts contains, soaked. It is then dried and then the metal salts thermally decomposed to form oxide.

In this manufacturing process, compliance with the Firing temperature is essential. It has been shown that precisely with the aforementioned Burning temperature a catalytically active body with extremely high activity is obtained.

The mixture of starting materials can, in addition to the metal oxides Al203 and MgO, which add up to 100 parts by weight, corresponding to that in the earlier application Current time P 22 10 438.7 already proposed method advantageously the following weight proportions the other substances contain: 2 to 4 parts of polyvinyl acetal (preferably 3 parts), 2 to 4 parts graphite (preferably 3 parts), 2 to 10 parts stamping oil (preferably 5 parts) and 10 to 30 parts of water (preferably 20 parts); additionally can also small amounts of other organic polymers, such as polyvinyl alcohol and more water-soluble Cellulose ether.

The starting materials for the production of the catalytically active body aluminum stearate can also be added, the aluminum stearate can at least partially replace the carbon content (graphite and / or soot). That Aluminum stearate serves to plasticize the mixture well and it also works pore-forming.

The catalyst materials - La, Co, Ni and U - can be beneficial can be used in the form of metal nitrates. But others can also turn to this soluble metal salts such as oxalates, acetates, carbonates, tetrammine complexes get there etc.; the salts should be easily thermally decomposable.

On the basis of ufhrungsbeispielen and two figures, the invention will be explained in more detail.

It shows Fig. 1 schematically in section a catalytically active body according to the invention and FIG. 2 schematically shows an arrangement for generating a fuel gas by converting higher hydrocarbons using a catalytically active one Body according to the invention.

For the production of a catalytically active body according to the invention 74 gOG aluminum oxide (corundum) and 26 g magnesium oxide are initially used together with 5 g punching oil, 3 g graphite, 3 g polyvinyl acetal (e.g. Mowi-talt9) and 20 ml wet mix intensively for two hours, for example using a twin-shaft mixer. The crumbly mass obtained in this way is advantageously further processed quickly in order to to prevent drying out - by escaping volatile components. Will the If the mass is not processed further immediately, it becomes airtight for storage locked.

The mass is sieved, for example through a sieve with a mesh size from about 0.05 to 0.1 mm, and the sieved portion is filled into a mold, whose filling space is larger than the final volume obtained after the pressing process Molded body. During the pressing process, the mass between two plates is initially precompressed, the volume ratio of precompressed mass to starting mass is approximately between 1: 1, 2 and 1: 3; preferably the volume ratio is about 1: 2. The pressure during pre-compression is about 1 to 3 N / mm2. Then become the Generation of the channels pins from the upper plate through the pre-compressed mass passed through and lowered into holes in the lower plate. Have the pens a diameter of about 0.8 to 2.0 mm; preferably the pins have one Diameter between about 0.8 and 1.3 mm. The number of pins and their diameter is chosen so that the cross-sectional line of all channels 10 to 70% of the area of the molded body. The area proportion of the channels is preferably between about 55 and 45%.

If the pins are inserted into the precompacted mass, then the pressure increases and the mass is completely compacted.

The pressure is between 5 and 50 N / mm²; it is advantageous about 10 to 20 N / mm2 and preferably about 15 N / mm2.

After the pressing process has ended, i.e. after the pressure has been relieved the pins pulled out of the molded body through the top plate. The molded body is removed from the mold, dried for 6 hours at about 1200C and then burned. The firing process takes place at a temperature between 1500 and 1580 ° C, preferably at about 1560 ° C. The burn time is about 40 hours and the actual The firing process, i.e. the firing process at the firing temperature, takes about 20 to 25 years Hours. During firing, the material sintered up to about 14600C and then a growth caused by crystal transformation (spinel formation) begins, which ends at about 15000C with a volume increase of about 20 to 25%. To around 15600 then there is a shrinkage to the original volume, a burning time of at least 8 hours required. The strength of a manufactured in this way Shaped body (catalyst carrier) amounts to about 70 to 100 N / mm² in the area of the channels.

In the manufacture of the alumina and magnesia containing As already stated, the catalyst carrier is the grain size of the magnesium oxide advantageously larger than that of aluminum oxide. By using a mixture from relatively fine Al 203 and relatively coarse MgO can be achieved that during of the firing processa overall, there is no shrinkage; good solidification achieved. In addition, such catalyst supports obtained catalytically active body with increased activity. Except the specific grain size ratios between the MgO and the Al203 is used in the Production of the catalyst support containing magnesium and aluminum oxide is preferred Uses magnesium oxide which has been melted before use.

The porosity of a manufactured according to the method described Sintered stone can be about 20 to 60% by volume; the porosity is advantageous about 40 to 45 vol. The pore volume should not exceed the upper limit of about 60% because otherwise the sintered stone has insufficient strength and thermal conductivity having. The lower limit of around 20% should therefore not be fallen below, because otherwise too little catalyst material can be introduced into the sintered stone.

The catalyst is introduced into the catalyst carrier for example in the following way: 5.9 g of lanthanum nitrate La (NO 3) 3 6 H 2 O, 3.25 g cobalt nitrate Co (N03) 2 e H20, 0.4 g nickel nitrate Ni (N03) 2 6 H20 and 0.1 g uranyl nitrate U02 (N03) 2 to 6 H20 are heated briefly to about 90 ° C in about 4 ml dissolved in distilled water. The solution is then allowed to cool to about 50.degree and so soaks a sintered stone with a weight of about 50 g.

After drying for about one hour at a temperature of about 100 ° C the metal nitrate-containing sintered stone is heated to a temperature for about 2 hours Heated from about 700 to 900 ° C, the metal nitrate decomposes and converted into oxides will. A catalytically active body produced in this way contains in the form of Oxides approximately the following amounts of metals: 70.6% by weight lanthanum, 24.6% by weight cobalt, 3.0 wt% nickel and 1.8 wt% uranium. For the sake of clarity, is the metal content of the catalyst is given in each case.

Subsequent to the decomposition of the metal salts, the sintered stone can still be heated in a reducing atmosphere, preferably under hydrogen. In this way, the light-up time and the light-up temperature of the - under Use of the catalytically active body - conversion reaction to be carried out can be reduced when the catalytically active body is used for the first time.

The introduction of the catalyst into the catalyst carrier can also be made in such a way that the individual components in different Steps are applied.

For example, a sintered stone can be advantageous after firing first be soaked with an aqueous solution of lanthanum nitrate. Afterward it is dried and heated in the air to around 750 to 90,000. The following is the sintered stone impregnated with an aqueous solution of salts of the remaining metals and treated further as already described.

A sintered stone produced by the method described is shown schematically in section in FIG. The sintered stone 10 consists of porous, sintered material 11. The sintered stone contains, as shown in FIG. 1 in a simplified manner is, catalyst material 12. In addition to the existing pores is the catalyst support 10 provided with channels 13 which are arranged approximately parallel to one another and penetrate the catalyst carrier from one surface to the other. The catalyst material is mainly arranged in the porous surfaces of the catalyst carrier as well in its porous areas which surround the passage channels 17.

In Fig. 2, an arrangement is shown schematically in section, in using the catalytically active body according to the invention from a Hydrocarbon / oxygen mixture, a fuel gas for an internal combustion engine is produced. The fuel, for example gasoline, is supplied with the help of a pump 20 conveyed through a pipe 21 into an evaporator 22 and evaporated there. On the evaporator 22 there is a mixing nozzle 23 for mixing the evaporated Fuel with the oxygen-containing gas. The mixing nozzle 23 can by a Pipe 24 air can be supplied. Through a pipe 25, the mixing nozzle 23 but also exhaust gas are fed to the internal combustion engine, the Contains oxygen in the form of C02 and H20. The mixture of evaporated fuel and oxygen-containing gas is at a temperature of, for example, about 500 " fed through a conduit 26 to a fission generator 27, i.

a device in which the conversion of the fuel into a combustible Fission gas, i.e. a fuel gas, takes place. in the gap gas generator 27 are catalytically active Body 28 arranged, for example sintered stones. The sintered bricks have passageways 29 on. The cracked gas, besides carbon monoxide, hydrogen and methane, something. Carbon dioxide as well as nitrogen and optionally also contains higher hydrocarbons, leaves the gap gas generator 27 through a mixing nozzle 3Q and arranged at its outlet is through a pipe 31 of an internal combustion engine 32, for example the engine of a motor vehicle supplied. The mixing nozzle 30 can pass through a pipe 33 Fresh air for mixing with the cracked gas before it is introduced into the engine are fed. In the internal combustion engine 32, the cracked gas is combined burned with the fresh air. The exhaust gases formed during combustion are released the internal combustion engine 32 discharged through a pipeline 34-ad into a heat exchanger 35 passed, which is part of the gap gas generator 27 and the Surrounds space 36 in which the catalytically active bodies 28 are arranged. By a pipe 37 exits the exhaust gas from the heat exchanger 35. The exhaust gas can then partially fed through the pipeline 25 to the mixing nozzle 23, the main amount of the exhaust gas enters a heat exchanger 38 attached to the evaporator 22 is. In the heat exchanger 35, the heat content of the exhaust gas is maintained the temperature required on the catalytically active body is used in the heat exchanger 38 for evaporating the fuel and for heating the evaporated fuel. In the pipe 51, a heat exchanger can also be provided, which for Kithlung de hot Spaltgil.ses serves and its thermal energy partly on the Starting components, i.e. fuel and / or containing oxygen () oxide; transmits.

The sintered stones 28 arranged in the gap gas generator 27 contain for example about 8% by weight of catalyst (in the form of lanthanum, cobalt, nickel and uranium oxide), based on the weight of the sintered stone. The sintered stones show a structure as already described. They have approximately the following dimensions: 46mm x 66mm x 14mm; four such sintered stones are parallel one behind the other arranged at a mutual distance of about 5 mm.

The mixture becomes the catalytically active bodies in the gap gas generator from gasoline vapor and oxygen transfer, for example, supplied at about 50 ° C. That The gasoline used, for example, has a composition corresponding to a medium one Molecular formula of C8H16. For example, there is one on the catalytically active body Temperature between about 8500C (on the first sinter stone) and about 7000C (on the last of the four oirntersteine) and the cracked gas leaves the cracked gas generator with a Temperature of about 60000. The conversion of gasoline in the hot gas generator is the same Temperature, depending on the load on the catalytically active body.

The catalytically active body according to the present invention shows catalytically at least up to a volume load of about 10 1 gasoline per dm3 (liter) active body and hour an almost complete conversion of the gasoline used.

When converting 1.6 l of gasoline with 2.5 m3 of air and 150 l of carbon dioxide (instead of exhaust gas from an internal combustion engine) per hour in the gap gas generator described (with four sintered stones with a total volume of about 0.17 l), i.e.

for example, at the above-mentioned volume loading, one obtains a cracked gas of the following composition (in vol.%): 20.5% CO, 19.5% H2, 1.7% CH4, 5.0% C3 and C4 hydrocarbons, 6.8% CO2, balance N2; the nitrogen comes from while doing it from the air.

In addition to an increased mechanical load capacity - compared to the catalytically active one described in the main patent Body - shows the catalytically active body according to the invention has an increased resistance to temperature changes as well as a longer service life, even at operating temperatures above 8000 C. Above that In addition, this catalytically active body shows a further improved activity, .H. a high conversion rate of the gasoline used, even with a high volume load.

With the help of the gap gas generator and the one used therein catalytically active body according to the invention, starting from a fuel With a low octane number, a fuel gas can be generated that allows knock-free operation made possible by internal combustion engines. The gap gas generator itself is in Detail is described, for example, in German Offenlegungsschrift 2 103 008. By using the fuel gas mentioned, you can also - in comparison compared to conventional gasoline engines - the pollutant emissions in the exhaust gas are considerably reduced will. When operating a motor vehicle with the help of a gap gas generator produced using the catalytically active body according to the invention Fuel gas, the values for carbon monoxide and nitrogen oxides in the exhaust gas are considerable below the values that result on the same engine when using gasoline. There is no need to accept a reduction in performance and the fuel consumption when can even be lowered a little.

In addition to the possibility of use already indicated, the inventive catalytically active bodies also used in other methods and devices Find. It can be used, for example, to produce a hydrogen-containing gas mixture for use in fuel cells, it can also be used for methane formation, are, in particular at temperatures between about 300 and 500 0'C; at temperature Ren in the range from about 600 to 8000C can be the catalytically active. Body for representation one containing hydrogen and carbon monoxide Gas mixture Methane can be used.

In addition, it can be used for the afterburning of exhaust gases with conventional powered motor vehicles are used.

Finally, the catalytically active body according to the invention can also in radiant burners, such as power plant burners, use. He can help a method can be used that is described in German Offenlegungsschrift 1 939 535 is described.

22 claims 2 figures

Claims (22)

Claims 1. Catalytically active body for converting higher Hydrocarbons, especially for conversion into carbon monoxide, methane and / or Gas gels containing hydrogen, according to patent .................. (Registration Akt.Z. P 22 10 365.7), characterized in that it consists of an oxidic catalyst support and a catalyst containing oxides of the metals lanthanum, cobalt, nickel and uranium and that the catalyst support is 23 to 27% by weight of magnesium oxide, preferably about 26% by weight, and 77 to 73% by weight of aluminum oxide, preferably about 74% by weight, contains. 2. Catalytically active body according to claim 1, characterized in that that the grain size of the magnesium oxide used as the starting material is larger as the grain size of the alumina used as the raw material. 3. Catalytically active body according to claim 2, characterized in that that the grain size of the alumina used as the starting material is less than 50 / u, preferably between 2 and 4 / u. 4. Catalytically active body according to claim 2, characterized in that that the grain size of the magnesium oxide used as the starting material is less than 100 / u, preferably between 40 and 60 Xu. 5. Catalytically active body according to one or more of the claims 1 to 4, characterized in that the catalyst 55 to 92 wt .-% lanthanum, 2 Contains up to 30% by weight cobalt, 1 to 10% by weight nickel and 0.1 to 8% by weight uranium, each based on the total content of these metals in the catalyst. 6. Catalytically active body according to claim 5, characterized in that that the catalyst 65 to 78 wt .-% lanthanum, 15 to 25 wt .- Só cobalt, 2 to 6 Contains by weight nickel and 1 to 2% by weight uranium. 7. Catalytically active body according to claim 5 or 6, characterized in that that he used lanthanum cobaltite LaCoO3 doped with nickel and uranium oxide as a catalyst contains. 8. Catalytically active body according to claim 5 or 6, characterized in that that the catalyst contains more lanthanum than the stoichiometric compound LaCoO3 corresponds. 9. Catalytically active body according to claim 8, characterized in that that the catalyst is about 70.6% by weight lanthanum, 24.6% by weight cobalt, 3.0% by weight nickel and 1.8 wt .- * uranium. 10. Catalytically active body according to one or more of the claims 1 to 9, characterized in that it contains 0.1 to 13 wt. Catalyst, based on the catalyst carrier. 11. Catalytically active body according to claim 10, characterized in that that it contains 5 to 9 wt .-, preferably about 8 wt .- *, based on catalyst the catalyst carrier. 12. Catalytically active body according to one or more of the claims 1 to 11, characterized in that the catalyst support is made of porous material consists. 13. Catalytically active body according to claim 12, characterized in that that the catalyst support has a porosity of 20 to 60 vol .-%, preferably about 40 to 45% by volume. 14. Catalytically active body according to claim 12 or 13, characterized in that that the catalyst carrier consists of preferably plate-shaped sintered bricks, those in addition to the pores with channels arranged approximately parallel to one another are provided. 15. Catalytically active body according to claim 14, characterized in that that it has about 10 to 70 channels per square centimeter of sintered stone surface, preferably about 40 to 60 channels. 16. Catalytically active body according to claim 14 or 5, characterized in that that the diameter of the channels is about 0.8 to 2.0 mm, preferably about 0.8 to 1.3 mm. 17. Process for the production of a catalytically active body according to one or more of claims 1 to 16, characterized in that 73 to 77 % By weight of aluminum oxide and 23 to 27% by weight of magnesium oxide, the oxide fractions 100% complete, as well as water, punching oil, graphite and / or carbon black and at least one organic, thermally degradable polymer are mixed as starting materials, that the mixture is introduced into a compression mold and pressed into a molded body, that the shaped body is fired at a temperature between 1500 and 15800C, that the catalyst support obtained with a lanthanum, cobalt, nickel and Uranium salts containing solution is impregnated and then dried and that the metal salts are thermally decomposed. 18. The method according to claim 17, characterized in that the shaped body firing at a temperature of about 156,000. 19. The method according to claim 17 or 1B, characterized in that is used as the organic polymer polyvinyl acetal. 20. The method according to any one of claims 17 to 19, characterized in that that in the starting materials graphite or carbon black at least partially by aluminum stearate is replaced. 21. The method according to one or more of claims 17 to 20, characterized characterized in that the catalytically active body after thermal decomposition the metal salts in a reducing atmosphere, preferably under hydrogen, is heated. 22. Use of a catalytically active body according to one or more of claims 1 to 16 for the production of carbon monoxide, methane and / or hydrogen Containing fuel gas for internal combustion engines, in particular for internal combustion engines in motor vehicles, through the reaction of higher hydrocarbons with oxygen or oxygen-containing gases.