DE2846254A1 - METHOD FOR PRODUCING AROMATIC HYDROCARBONS BY CATALYTICALLY CONVERTING CARBON MONOXIDE AND HYDROGEN - Google Patents

Description

SHELL INTERNATIONAL RESEARCH MAATSCHAPPIJ B.V. The Hague, Netherlands

Process for the production of aromatic hydrocarbons through the catalytic conversion of carbon monoxide and hydrogen

claimed priority:

Oct. 26, 1977 - Netherlands - No. 7711719

Hydrocarbon units boiling in the gasoline sector can be for example by direct distillation of crude mineral oil, by converting heavy mineral oil fractions, such as by catalytic cracking, thermal cracking or hydrocracking, also by converting light mineral oil fractions, e.g. through alkylation. These hydrocarbon mixtures are often used to improve the octane number catalytically subjected to reforming, v, 'cäurch uer content εη aromatic compounds increases.

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In view of the increasing demand for petrol and the steadily decreasing mineral oil reserves, there is great interest today of processes with which carbon-containing substances that are not based on mineral oils, for example coal, can be economically processed in an acceptable manner in hydrocarbon mixtures. that you can convert in the gasoline sector. These hydrocarbon mixtures should have a sufficiently high octane number to be usable as gasoline without further refining.

It is known that carbon-containing substances, such as coal, can be converted into mixtures of carbon monoxide and hydrogen in a relatively simple manner by means of gases with water vapor. It is also known that mixtures of carbon monoxide and hydrogen with a molar ratio of H ₂ : CO above 1.0 can be converted into hydrocarbon mixtures with good yield by contacting a gas mixture with suitable catalysts. Attempts to achieve an economically viable process for making gasoline from carbonaceous materials such as coal by combining these two processes have encountered considerable difficulty. The main problem is the composition of the mixture of carbon monoxide and hydrogen produced when gasifying with water vapor, as well as the composition of the hydrocarbon mixture produced during the conversion of the gas mixture.

It was found that gasification with steam for the production of mixtures of Kohlemuonoxiu unu Hydrogen in high yield and to suppress the formation of methane, tarry products and phenols

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Temperatures above 100 ° C should work. In addition, the molar ratio of H ₂ : CO in the product obtained in the gasification with steam is very dependent on the temperature used. At temperatures above 100 ° C., gas mixtures with a molar ratio of H ₂ : CO below 1.0 are obtained. These gas mixtures are less suitable for conversions in the second stage of the above-mentioned combination process, in which gas mixtures with a ratio of H ~: CO above 1.0 are desired. An application of the water gas balancing reaction with these gas mixtures with a low ratio of H ₂ : CO to increase this ratio to above 1.0 is not suitable for economic reasons, since then the gas mixtures obtained in this way with an increased H ₂ : CO ratio are expensive Gas separation treatment to remove any carbon dioxide formed must be subjected to before the gas can be converted in the second stage of the combination process.

The hydrocarbon mixture formed in the conversion of mixtures of carbon monoxide and hydrogen has a very high broad molecular weight distribution and contains almost no aromatic compounds. This means that only part of this mixture consists of hydrocarbons boiling in the gasoline range and that this part increases the aromatic content Compounds must be catalytically reformed before it can be used as gasoline.

The notifying party has now carried out investigations to determine whether the manufacture of high octane aromatic hydrocarbon mixtures intended for use as a

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Gasoline without further refining are suitable from mixtures of Carbon monoxide and hydrogen, as they are produced from carbonaceous substances during gasification with water vapor at high temperatures, like coal to be preserved is possible. The focus of these investigations was on a one-step conversion.

It was found that aromatic hydrocarbon mixtures with a high octane number by contacting a gas mixture with a catalyst, eggs combines three functions, can produce.

The invention thus provides a process for the production of aromatic hydrocarbons by catalytic conversion of carbon monoxide with hydrogen, which is characterized in that a mixture of carbon monoxide and hydrogen with a molar ratio of H ₂ : CO below 1.0 is used in one stage in converts a mixture of aromatic hydrocarbons by contacting the gas mixture with a trifunctional catalyst, the at least one metal component with catalytic activity for the conversion of H ₂ / CO mixtures into hydrocarbons and / or oxygen-containing hydrocarbons, at least one metal component with catalytic activity for the water gas formation reaction and a crystalline silicate containing

a) is thermally stable at temperatures above 600 ^{0 C,}

b) after dehydration at 400 ° C. under reduced pressure, over 3 percent by weight of water at 25 ° C. and saturated Can adsorb water vapor pressure and

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c) has the following composition in dehydrated form in MoI tier Oxiae:

(1.0 + 0.3) (R) _{2 / n} O · / "a ^Fe 2 ^O 3 ' ^{b Al} 2 ^O 3 * ^{c Qa} ₂ ° 3 ^' y (d SiO ^. E GeO ^), where

R one or more mono- or divalent cations, a) / 0.1,

a + b + c = 1,
7) 10

d + e = 1 and

η is the valence of R.

The mixture of carbon monoxide and hydrogen used in the process according to the invention with a molar ratio of H ₂ JCO below 1.0 can easily be produced by gasifying a carbon-containing material with water vapor at high temperature. Suitable starting material is lignite, anthracite, coke, crude mineral oil and its fractions as well as oils extracted from Teersana and bituminous tar slate. The starting material present in finely divided form becomes with

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Water vapor, oxygen or air, which is optionally enriched with oxygen, is converted into a gas mixture which contains hydrogen, carbon monoxide, carbon dioxide, nitrogen and water, among others. This gasification takes place with steam preferably at a temperature of 1000 to 2000 C and a pressure of 10 to 50 bar. To remove impurities such as ashes, carbonaceous substances and hydrogen sulfide, obtained from the Removing gas becomes the gas that has a temperature

first cooled above 1000 ° C to a temperature of 100 to 20 ° C. This cooling is expediently carried out in a boiler in which steam is generated with the aid of the waste heat. That Cooled gas can then be freed from almost all solids by washing with water. After this wash while If the temperature of the gas falls to 20 to ÖO ° C, it will Gas by removing the hydrogen sulfide and carbon dioxide further cleaned. This is best done using the ADIP or SuIfinol process.

The trifunctional used in the process according to the invention In addition to the metal components, the catalyst contains a special kind of crystalline silicate. These silicates have an effect a high conversion of aliphatic hydrocarbons into aromatic hydrocarbons in economically interesting yields and generally prove to be effective in Umwanulungsreaktioneiv, ah which aromatic hydrocarbons are involved, as very active.

In the process according to the invention, silicates are preferred which

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do not contain gallium or germanium, i.e. / silicates in which ο and e have fourth 0 in the overall composition given above. These silicates are in NL patent application 7613957 described. In addition, it is in the method according to the invention Silicates are preferred in which, in the overall composition mentioned above, a is greater than 0.3, in particular greater than 0.5. Particularly preferred are silicates that do not contain aluminum, i.e., for uenen in the overall composition b has the value 0. In the case of aen preferred silicates in the process according to the invention, y preferably has aen value < 600 and especially less than 3OO. Finally, in the method according to the invention those silicates are preferred whose X-ray diffraction diagrams include those in Table A of dL patent application 7613957 has specified reflection values.

The relationship in aem the three catalytic functions in aem trifunctional used in the process according to the invention Catalyst occur can fluctuate within wide limits and is mainly due to the activity of each individual this catalyst functions determined. The aim of the invention Process is the acyclic hydrocarbons formed under the action of the first catalyst function and / or Oxygenated hydrocarbons as completely as possible with The second catalytic converter function is to convert it into a mixture of aromatic hydrocarbons that is in the range of gasoline boils. With the third catalyst function, the water released during this conversion should as completely as possible with aem excess carbon monoxide in the C0 / H2 mixture to form a "water

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substance / carbon dioxide mixture react. In an optimal trifunctional Catalyst for the process according to the invention, which has a certain amount of the first catalyst function contains a certain activity, it is possible to use the less of the other catalyst functions, the more active these are.

Although the trifunctional catalysts which can be used in the process according to the invention are described as catalysts that contain one or more metal components with catalytic activity for converting an H ₂ / CO mixture into hydrocarbons and one or more metal components with catalytic activity for the water gas formation reaction, this does not mean at all that metal components, which each have one of the two catalytic functions, should always be present separately in the catalysts. It has been found that metal components and combinations of metal components with catalytic activity for the conversion of an H ₂ / CO mixture into acidic

Substantial hydrocarbons are usually sufficient

/ have high catalytic activity for the water gas formation reaction, so that in such a case it is sufficient to incorporate only one metal component or a combination of metal components into the catalysts. Examples of such metal components are zinc, copper and chromium. If trifunctional catalysts containing these metals are used in the process according to the invention, preference is given to those which contain combinations of at least two of these

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contain metals, for example the combination of zinc and copper, Zinc-chromium or zinc-copper-chromium. Particular preference is given to a trifunctional catalyst, which apart from the crystalline Silicate contains the metal combination zinc-chromium. Metal components and combinations of metal components with catalytic activity for the conversion of an H ^ / CO mixture into Hydrocarbons generally have no or only a few

That's why

Activity for the water gas reaction biluna on, / should be used when using such metal components or combinations of metal components in the catalyst also include one or more separate ones Metal components with catalytic activity for the water gas formation reaction to be available.

The trfunctional used in the process according to the invention Catalysts are preferably composed of two or three separate catalysts, which for the sake of simplicity as Catalysts X, Y and Z are designated. The catalyst X contains the metal components having the catalytic activity for the conversion of a H ^ / CO mixture into hydrocarbons and / or oxygen-containing hydrocarbons. The catalyst Y is the crystalline silicate. Catalyst Z contains aie metal component with the catalytic activity for water gas formation. As already mentioned above, the use a Z-catalyst occasionally ^ omitted.

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BATH ORIGINAL

If the X catalyst used is a catalyst which is able to convert an H ₂ / CO mixture into oxygen-containing hydrocarbons, preference is given to a catalyst which is able _{to convert the H 2} / CO mixture in - methanol and / or dimethyl

to convert ether. Catalysts with the metal combinations described above are particularly suitable for converting an H _{2 / CO mixture into = -_- methanol.} The metal combinations mentioned can optionally be applied to a carrier material. By introducing an acidic function into these catalysts, for example by incorporating the metal combination into an acidic carrier, it can be effected that not only the conversion of the H ^ / GO mixture to methanol takes place, but also a considerable proportion of the mixture to dimethyl ether is converted.

The X catalysts, which are able to convert a Hj / CO mixture into - hydrocarbons,

are referred to in the relevant literature as Fischer-Tropsch catalysts. Such catalysts often contain one or more metals of the iron group or ruthenium, together with one or more promoters to increase the activity and / or selectivity and occasionally, a support material such as kieselguhr. The catalysts can ren by precipitation, melting and impregnation •. Are produced. The manufacture of catalysts

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with one or more "metal (s) of the" iron group
Impregnation is carried out by impregnating a porous carrier with one or more aqueous solutions of salts of metals of the iron group and optionally promoters and then drying and calcining the composition. Is in the inventive

If the process uses a catalyst combination in which the X catalyst is a Fischer-Tropsch catalyst, an iron or cobalt catalyst is preferably chosen for this purpose, but in particular a catalyst
which has been produced by impregnation. Fischer-Tropsch catalysts which are very suitable for use in the catalyst combinations according to the invention are those which have been obtained by impregnation in accordance with Do-OS 27 50 007

have been manufactured. These catalysts each contain 100 parts by weight of support material
10 to 75 parts by weight of one or more metals
Iron group, together with one or more promoters
in a mer.ga of 1 to 50 percent, based on the amount of metals of the iron group present in the catalyst, the specific average pore diameter (p) of these catalysts being at most 10,000 nm and the specific average particle diameter "(d) of these catalysts with a maximum of 5 mm are dimensioned so that the quotient p / d is more than 2 Cp in nm and d in rsm).

It is in the process according to the invention

the goal of using a catalyst combination

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the X is a Fischer-Tropsch iron catalyst, so choose one preferably uses an iron catalyst that has a promoter combination from an alkali metal, an easily reducible metal such as copper or silver, and optionally a metal that is difficult to reduce, such as aluminum or zinc. One for the present purpose A very suitable iron catalyst is a catalyst made by impregnation which contains iron, potassium and copper contains on silicon dioxide as a carrier material. Should in

If a catalyst combination is used according to the invention in which X is a Fischer-Tropsch cobalt catalyst, a cobalt catalyst with a promoter combination of an alkaline earth metal and thorium, uranium or cerium is preferably used. A Fischer-Tropsch cobalt catalyst which is very suitable for the present purpose is a catalyst produced by impregnation which contains cobalt, magnesium and thorium on silicon dioxide as support material. «Other very suitable Fischer-Tropsch cobalt catalysts produced by impregnation are those which which, in addition to cobalt, contain one of the elements chromium, titanium, zirconium and zinc on silicon dioxide as a carrier material. If necessary, catalyst combinations can also be used in the process according to the invention which contain an -X catalyst which is able _{to convert an H 2} ZCO-GeHIiSCh into a mixture which contains both hydrocarbons and oxygen-containing hydrocarbons in comparable amounts

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contains. ^{111 usually} has such a catalyst, sufficient catalytic activity for the water gas reaction so that the use may be a Z-catalyst in combination omitted. An example of an X catalyst of this type is an iron-chromium oxide catalyst. Optionally, in the process according to the invention

Catalyst combinations can also be used which contain two or more X-catalysts, for example in addition to a catalyst of type X, which is able to convert an H2 / C0 mixture into hydrocarbons, a second catalyst of type X, which is able is, an H ₂ / CO mixture in 'oxygen-

to convert containing hydrocarbons.

Z-catalysts that are able to produce an H-O / CO mixture to convert into an H / CO mixture, are described in the relevant Literature referred to as catalysts for the formation of water gas. Such catalysts often contain one or more of the metals iron, chrome, copper, sink, cobalt, nickel and molybdenum as catalytically active Component, either as such or in form their oxides or sulfides. Examples of suitable catalysts for the formation of water gas are the mixed sulfidic ones Catalysts according to Dutch patent applications No. 7 305 340 and No. 7 304 79 3 and the spinel catalysts according to DE-OS 27 50 006.

Is used in accordance with the rinäur.gs Process uses a catalyst combination in which

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BATH ORIGINAL

if a Z-catalyst is present, one preferably chooses one Catalyst containing both copper and zinc., In particular, but a catalyst in which the atomic ratio of Cu / Zn is between 0.25 and 4.0.

In the case of the trifunctional catalysts, the catalysts X, Y and optionally Z can be present as a mixture in which each particle of the catalyst X is in principle surrounded by a large number of particles of the catalyst Y and optionally the catalyst Z, and vice versa. If the process is carried out using a fixed catalyst bed, this can consist of layers of particles of the catalysts X, Y and optionally Z arranged alternately. If the two or three catalysts are used as a mixture, this can be a macro or micro mixture. In the former case, the trifunctional catalyst consists of two or three kinds of macroparticles, one of which is formed exclusively from the catalyst X, the second exclusively from the catalyst Y and the third exclusively from the catalyst Z. In the second case, the trifunctional catalyst consists of a type of macroparticle, each macroparticle being formed from a multiplicity of microparticles of each of the catalysts X, Y and optionally 2. "Trifunctional catalysts in the form of" micro mixtures can be prepared, for example, by a finely divided powder of the catalyst X intimately nit a finely divided powder of the catalyst Y and optionally with a

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finely divided * powder des-catalyst-Z mixed and the mixture shaped into larger particles, for example by

Extrude or press together. ^{In the process according to the} invention, preference is given to using trifunctional catalysts in the form of micro mixtures. These trifunctional catalysts can also have been produced by adding the metal components with the catalytic activity for converting an H / CO mixture into hydrocarbons and / or oxygen-containing hydrocarbons and optionally the metal components with catalytic activity for water gas formation to the crystalline silicate incorporated, for example by impregnation or by ion exchange.

The crystalline silicates used in the process according to the invention are generally prepared from an aqueous mixture as the starting material which contains the following compounds in a certain ratio: one or more compounds of an alkali or alkaline earth metal, one or more compounds with a monovalent or divalent organic Cation, or from which such a cation is formed during the production of the silicate, "one or more silicon compounds, one or more iron compounds" and optionally one or more aluminum, gallium and / or germanium compounds.

The preparation is carried out by the fact that the mixture up to

Education/

/ "of the silicate keeps at an elevated temperature and

then separates the silicate crystals from the mother liquor

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The silicates formed in this way contain alkali and / or alkaline earth metal ions and mono- and / or divalent organic cations. Before use in the invention The process will incorporate at least a portion of that incorporated into the crystalline silicate during manufacture mono- and / or divalent organic cations in hydrogen ions converted, for example by calcination, and at least part of the crystalline silicate during the Production of incorporated exchangeable mono- or divalent cations is preferably carried out by other ions, in particular Hydrogen ions, ammonium ions and / or ions of the Rare earth replaced. The crystalline silicates used in the process according to the invention have preferably an alkali metal content of less than 1 percent by weight and in particular below 0.05 percent by weight. If necessary, the in the invention

Catalysts used in processes a binder, for example bentonite or kaolin, are incorporated.

The inventive. Process is preferably carried out at temperatures between 200 and 500 ° C and in particular at Temperatures between 300 and 450 ° C, pressures between 1 and 150 bar, in particular between 5 and 100 bar, and space velocities between 50 and 5000, especially between 300 uiid 3000 Nl gas / l catalyst / hour.

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- vr-

The process according to the invention can be carried out in a very suitable manner by feeding in from below upwards or from top to bottom through a vertically arranged reactor, in which there is a fixed or movable Bed of the trifunctional catalyst in question is located. The inventive method can, for example, in the so-called Fixed bed process, in bunker flow operation or using an expanding catalyst layer. Preferably here are catalyst particles with a Diameter between 1 and 5 mm used. If necessary, can the process also with a fluidized catalyst bed or by means of a slurry of the catalyst in a hydrocarbon oil be performed. In this case, catalyst particles with a diameter between and 150yum used.

The examples illustrate the invention.

example 1

A crystalline iron silicate (silicate A) is made from a mixture of iron (III) nitrate, silicon dioxide, sodium nitrate and a compound of the formula / Tc ₃ H ₇ J ₄ NjOH in a molar ratio νΰμ Na ₂ O.1.5 / Tc ₃ H ₇ J ₄ NJ ₂ OvO, 125 Fe ₂ O ₃ .25 SiO ₂ .468 H ₃ O in water 'by heating for 48 hours in an autoclave at 150 ° C. under autogenous pressure. After cooling, the silicate formed is filtered off and washed with water until

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the pH value of the washing water is about 8 ₍ .una 2 hours dried at 120 ° C. The silicate A produced in this way has the composition 0.0 / (C ₃ H -). tf / ^ OO.3 Yes.0. Fe ₀ O-.200 55 H ₂ O.

The X-ray diffraction diagram corresponds to that given in Table B of NL-PS 7613957. This silicate at temperatures up to about 900 ⁰ C thermally stable una aasorbiert NaCN aer dehydration at 400 C under pressure verminuertem 7 weight percent water at 25 C una saturated Wasserdampfaraok.

From this silicate A, silicate B is produced by calcining at 500 ° C, sieving with 1.0 M ammonium nitrate solution, washing with water, again boiling with 1.0 M ammonium nitrate solution, washing, drying for 2 hours at 120 ° C and calcining for 4 hours at 500 ° C .

Example 2

According to the procedure of Example 1, a crystalline silicate (silicate C) is produced, with the difference between what the aqueous mixture contains in addition to the iron (III) nitrate but also contains aluminum nitrate and has the following molar composition: Na ₂ 0.4.5 / Tc ₃ H ₇ ) ^ Jp ' 0.35 Al ₂ O ₃ . 0.15 Fe ₃ O ₃ . 29.1 SiO ₂ . Abu h ^ O. The silicate C produced in this way has the composition 0.35 / Tc ₃ U ₇ ) ₄ oJ / ₂ 0.0.2 Yes ₂ O. 0.15 Fe 0, U, 35 Ai, U.

31 SiO ₂ . 9 H ₂ O.

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The X-ray diffraction diagram corresponds to that in Table B aer i> IL-PS 7613957. This silicate is up to temperatures above 1000 ° C thermally stable and adsorbed after draining at 400 ° C under reduced pressure ö weight percent water at 2d ° C unu saturated water vapor pressure.

Silicate D is produced from silicate C as indicated for silicate B.

Example 3

By mixing a mixture of zinc oxide and chromium oxide with the crystalline rock silicate B in a weight ratio of 3: 1, a catalyst for the reduction of carbon monoxide to methanol and for the formation of water gas is produced. Both materials are present in the catalyst in the form of particles with a diameter of 0.15 to 0.3 mm.

The catalyst thus obtained by mixing is used in a one-step process for producing a mixture of aromatic hydrocarbons from a mixture of carbon monoxide and hydrogen. The reaction takes place in a 50 ml reactor in which there is a fixed catalyst bed with a volume of 7.5 ml. The h-VCO mixture with a molar ratio of 0.5 v / ird is passed over the catalyst at a temperature of 375 ° C., a pressure of 60 bar and a space velocity of 1000 standard l of gas / liter of catalyst / hour. The results are summarized in Table I.

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BATH ORIGINAL

Table I.

CO conversion,% 50

H, conversion,% 53

Product composition,
Percentage by weight, based on C. Proaukt

C ₄ to

Product composition,
Percentage by weight, based on C ₅ product

Paraffins + olefins 20

Naphthenes 27

Aromatics 53

Example 4

Following the procedure of Example 3, by mixing zinc oxide and chromium oxide with the crystalline iron-aluminum silicate P in a weight ratio of 5: 1 a catalyst in the form of particles with a diameter of 0.15 to 0.3 mm manufactured. This catalyst is used in a single-stage process for the production of a mixture of aromatic hydrocarbons from a mixture of carbon monoxide and water

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substance with a molar ratio of H ~: CO of 0/5 is used. The reaction is carried out according to Example 3, with the difference / that they are at a temperature of 35O ° C and a pressure of 80 bar. The results are summarized in Table II.

Tables

CO Conversion /% 54

! ^ - conversion /% 59

Price composition,
Percentage by weight, based on C ₁ product

C ₁ 2

C ₂ .2

C ₃ 10

C ₄ 13

^C 5 " ^C 12 ⁶⁹

C ⁺ 4

Product composition,
Percent by weight / based on C ₅ product

Paraffins + Olefins' 18

Naphthenes ¹ 2O

Aromatics 62

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Claims (6)

Claims 1. A process for the production of aromatic hydrocarbon lotion by catalytic conversion of carbon monoxide with water toif, characterized in that a mixture of carbon monoxide and hydrogen with a molar ratio of H ₂ : CO below 1.0 is converted into a mixture of aromatic in one stage Hydrocarbons are converted by contacting the gas mixture with a trifunctional: \ <v; .aXyaacur, via at least one metal component with catalytic activity, the conversion of H ^ / CO mixtures into hydrocarbons and hydrocarbons containing oxygen, at least one H component catalytic activity, for the water gas formation reaction and a crystalline silicate that contains a) is thermally stable at temperatures above 600 C, b) after dehydration at 400 ° C. under reduced pressure can adsorb over 3 percent by weight of water at 25 C unu saturated water vapor pressure and c) has the following additions in dehydrated form, ang ^ -obon in moles of oxides: (1.0 + 0.3) (R) _{2 / n} 0. [a Fe ₂ O ₃ .b Al ₂ O ₃ . c Ga ₀ O ₃ J. y (d SiO ₂ + e GeO ₃ ) -, where R is one or more monovalent or divalent cation (s), a> / 0.1, b> 0, c> 0, a + b + c = 1, y> / io, 8 / OS4 1 BATHROOM 0RK3WAL e> 0, d + e - 1 and η is the valence of Rist 2. Process according to spoke 1, characterized in that a trifunctional catalyst is used which consists of separate catalysts, with catalyst X uie Metallkoinuoncnto with uer catalytic activity for uie Umwanulung the H ^ / CO mixtures in hydrocarbons, catalyst Y uas crystalline Silicate and catalyst Z contains the metal component with external catalytic activity for a water gas formation reaction. 3. The method according to claim 1 and 2, characterized in that aass an iron or cobaite catalyst is used as catalyst X. 4. The method according to claim 1 and 2, aauurch characterized in that a catalyst is used as catalyst Z, which contains copper and zinc, 'preferably in an atomic ratio of 0.25 to 4.0. 5. The method according to claim 1 to 4, characterized in that a 'trifunctional _/ consisting of macro-particles catalyst vtarwe-suet, in acr. Each macroparticle consists of a large number of microparticles from all three catalysts X, Y 909818/0 8 41 BATH ORIGINAL or Z is built up. 6. The method according to claim 1 to 5, characterized in that that it is at a temperature of 200 to 500 C, preferably 300 to 450 ° C, a pressure of 1 to 150 bar, preferably up to 100 bar, and a room velocity of 50 to 5000, preferably 300 to 3000 Wl gas / liter catalyst / stunue, performs. 9098 ¹ 8/084 1