WO2017207108A1

WO2017207108A1 - Method and installation for producing ethanol

Info

Publication number: WO2017207108A1
Application number: PCT/EP2017/025106
Authority: WO
Inventors: Andreas Peschel; Andreas Obermeier
Original assignee: Linde Aktiengesellschaft
Priority date: 2016-06-01
Filing date: 2017-05-04
Publication date: 2017-12-07
Also published as: DE102016006710A1

Abstract

The invention relates to a method (100) for producing of ethanol from synthesis gas using an ethanol direct synthesis gas reactor (3) which is equipped with a catalyst and which is designed to directly convert carbon monoxide and hydrogen and/or carbon dioxide and hydrogen into ethanol as a main product. According to the invention, the synthesis gas is initially fed to a methanol synthesis reactor (2) which is equipped with a catalyst and which is designed to convert carbon monoxide and hydrogen into methanol as a main product, and a component mixture extracted from the methanol synthesis reactor (2) is guided at least in a non-separated part to the ethanol direct synthesis gas reactor (3). The invention also relates to a corresponding installation.

Description

Description Process and plant for the production of ethanol

The invention relates to a process and a plant for the production of ethanol from synthesis gas according to the preambles of the independent claims.

State of the art

An overview of the properties, production and use of ethanol can be found in popular reference works, for example in the article "Ethanol" in Ullmann's Encyclopedia of Industrial Chemistry, published online October 15, 201 1, DOI: 10, 20.10, 2002 / 14356007.a09_587.pub2.

The production of ethanol is currently predominantly fermentative from biomass. In addition to biomass, synthesis gas can also be converted to ethanol by fermentation. Corresponding processes are also referred to as gas fermentation and are described, for example, in Brown, R.C .: "Biorenewable Resources: Engineering New Products from Agriculture", Arnes, Iowa State Press, 2008.

The chemical synthesis of ethanol from synthesis gas is also known. It can be carried out, for example, via the intermediate methanol, which is then homologated to ethanol and possibly other higher alcohols. Corresponding methods are disclosed in US 4,882,360 A and US 2013/0123377 A1. Another route is the conversion of methanol to acetic acid and the subsequent hydrogenation of acetic acid to ethanol. Examples include the so-called TCX and the so-called SaaBre process. The production of ethanol by carbonylation of methanol or the hydration of ethylene is also known.

Also, the direct chemical synthesis of ethanol from synthesis gas, based on catalyst systems with the elements rhodium, ruthenium, cobalt and / or iron, is possible. The present invention relates to corresponding methods. An overview of the catalysts can be found in Subramani, SK and Gangwal: "A Review of Recent Literature to Search for an Efficient Catalytic Process for the Conversion of Syngas to Ethanol", Energy & Fuels 22, 814-839, 2008. A corresponding catalyst which produces relatively selective ethanol and in particular hardly higher alcohols is disclosed in Hu et al., "Conversion of Biomass-Derived Syngas to Alcohols and C2 Oxygenates using Supported Rh Catalysts in a MicroChannel Reactor", Catalysis Today 120, 90-90. 95, 2007.

A problem with the direct synthesis of ethanol is that the sales of the

Synthesis gas and the selectivity to ethanol are relatively low. Also, the catalyst systems used are very expensive by the use of precious metals, especially rhodium. The present invention therefore has the object to improve known processes for the production of ethanol from synthesis gas.

DISCLOSURE OF THE INVENTION This object is achieved by a process and a plant for the production of ethanol from synthesis gas having the features of the independent patent claims. Embodiments are each the subject of the dependent claims and the following description. Advantages of the invention

The present invention is based on the finding that it is particularly advantageous not to supply synthesis gas directly to an ethanol direct synthesis reactor for the direct synthesis of ethanol, but to partially react the synthesis gas initially in a prereactor in the form of a methanol synthesis reactor and to produce methanol there. In this way, in the context of the present invention as a whole an increased synthesis gas conversion can be achieved. This is unexpected, since initially it would have been suspected that by using an additional

Methanol synthesis reactor, the costs and effort of the process would have been significantly increased without these costs and this expense would have been justified beneficial effects. However, as has been recognized in the context of the present invention and explained below, the potentially higher costs of several synthesis reactors are more than offset by the advantages that can be achieved therewith. The present invention proposes a process for the production of ethanol from synthesis gas using an ethanol direct synthesis reactor equipped with a catalyst designed to directly convert carbon monoxide with hydrogen and / or carbon dioxide with hydrogen to ethanol as the main product. In the context of the present invention, a "synthesis gas" is understood to mean a gas mixture which contains at least predominantly carbon monoxide and hydrogen. More details are given below. As part of the

Present invention, the above-mentioned direct synthesis of ethanol is used. This means that in the context of the present invention, ethanol is synthesized at least in part without the formation of removable intermediates from carbon monoxide and hydrogen. Possibly formed in the direct synthesis of ethanol intermediates react at least partially, especially still on

Catalyst, immediately to ethanol and therefore can not be separated. A process for the direct synthesis of ethanol therefore differs from the above-mentioned process for the two-stage synthesis of methanol or acetic acid, which are formed as separately handled and especially separable intermediates and then further reacted.

It is envisaged that the synthesis gas is first a methanol synthesis reactor, which is equipped with a catalyst which is designed to convert carbon monoxide with hydrogen and / or carbon dioxide with hydrogen to methanol as the main product is supplied, and that a methanol synthesis reactor extracted component mixture at least partly unseparated

Ethiloldirektsynthesereaktor is supplied. The methanol synthesis reactor is therefore in the context of the present invention directly upstream of the

Ethanoldirektsynthesereaktors arranged and a product stream of

Methanol synthesis reactor is fed without separation to the ethanol direct synthesis reactor. However, it can be between the methanol synthesis reactor and the

Ethanol direct synthesis reactor recycled methanol can be fed. Furthermore, optionally recirculated or freshly used carbon dioxide can be fed. Thus, the component mixture supplied to the ethanol direct synthesis reactor comprises at least all components of the methanol synthesis reactor, apart from changes caused, for example, by further reactions

Component mixture. However, this does not exclude that shares of the

Methanol synthesis reactor extracted component mixture without material Separation between the mentioned synthesis reactor can be discharged. Advantageously, in the context of the present invention, no active pressure influencing between the synthesis reactors, so no compression or relaxation. However, a temperature influence, for example by cooling or heating, may also be provided within the scope of the invention.

The person skilled in the art is familiar with ethanol direct synthesis reactors equipped with a catalyst suitable for the direct conversion or direct synthesis of

Carbon monoxide with hydrogen and / or of carbon dioxide with hydrogen to form ethanol as the main product, from the above-mentioned prior art and can therefore select a corresponding catalyst targeted and without difficulty. Details of corresponding catalysts are also given below. Is this the case that the catalyst "for the direct implementation of

Carbon monoxide is formed with hydrogen and / or of carbon dioxide with hydrogen to ethanol as the main product ", is understood hereunder that under the influence of the catalyst, a direct reaction of carbon monoxide with hydrogen to ethanol takes place without the formation of separable intermediates, as already explained above.

Direct synthesis of ethanol does not preclude the formation of other compounds. Thus, methanol can also be formed in not insignificant amounts in the direct synthesis of ethanol. However, one of the main products of direct synthesis is ethanol. A main product of a synthesis is here understood to mean a product which has a molar fraction of more than 10%, in particular more than 10%, more than 20%, more than 30%, more than 40%, more than 50%, more than 60% %, more than 70%, more than 80% or more than 90%, based on all formed in the synthesis

Products, includes. If, for example, 50% ethanol and 50% methanol are formed in a direct synthesis of ethanol, the ethanol formed is still one or one of the main products of the synthesis. In the case of the direct synthesis of ethanol used in the context of the present invention, methanol is also formed, but preferably only small amounts of other, ie higher, alcohols. These therefore preferably form only by-products. However, if necessary, not inconsiderable amounts of methane are formed. The particular product spectrum formed depends essentially on the catalyst used. Here is the speech that a mixture "predominantly" contains one or more components, is below understood that the mixture contains the one or more components to at least 40%, 50%, 60%, 70%, 80%, 90%, 95% or 99%.

Methanol synthesis reactors, which are equipped with a catalyst which is designed to convert carbon monoxide with hydrogen and / or carbon dioxide with hydrogen to methanol as the main product, the skilled worker also known from the prior art, for example from the article "methanol" in Ullmann's Encyclopedia of Industrial Chemistry, Online Edition October 15, 2012, DOI: 10.1002 / 14356007.a16_465.pub3, Section 4.2, "Catalysts". For one

Catalyst, which is "designed to convert carbon monoxide with hydrogen and / or carbon dioxide with hydrogen to methanol as the main product", the above applies accordingly. Using an appropriate catalyst, methanol is formed as the main product in the illustrated sense, but not or only slightly ethanol. Ethanol is preferably formed only in a molar proportion of at most 1%, 0.5% or 0.01% based on the total products. This distinguishes a corresponding catalyst from the catalysts for the direct synthesis of ethanol, which provide ethanol as the main product and also methanol in significant amounts. In both cases, carbon dioxide also reacts with hydrogen, with either ethanol or methanol being the main product. Further details on the reactions taking place in corresponding reactors are explained below.

An ethanol direct synthesis reactor, as can be used in the context of the present invention, can be operated, for example, at a pressure of 20 to 100 bar and a temperature of 200 to 300 ° C. Typical conditions and catalysts are given in the cited literature. The chemical

Reactions typically occurring on a catalyst system for the direct synthesis of ethanol from synthesis gas are:

Ethanol formation: 4 H ₂ + 2 CO - CH ₃ CH ₂ OH + H ₂ O

Methane formation: 3 H ₂ + CO CH ₄ + H ₂ O

Methanol formation: 2 H ₂ + CO CH ₃ OH

Water gas shift: H ₂ 0 + CO - C0 ₂ + H ₂

Ethane formation: 5 H ₂ + 2 CO - C ₂ H ₆ + 2 H ₂ O Depending on the catalyst used, part of the methanol formed and the methanol present in the inlet stream of the respective synthesis reactor are converted to ethanol and higher alcohols:

CH ₃ OH + CO + 2H ₂ --CH ₃ CH ₂ OH + H ₂ 0

In the context of the present invention, a catalyst is used in the methanol synthesis reactor, which is formed into a corresponding reaction. By using an ethanol synthesis reactor upstream

Methanol synthesis reactor, therefore, the overall yield of ethanol can be increased. The ethanol synthesis reactor can be made smaller and requires smaller amounts of expensive and limited available noble metal catalysts. A methanol synthesis reactor, as it can be used in the context of the present invention, for example, at a pressure of 20 to 100 bar and a temperature of 180 to 280 ° C are operated. A portion of the synthesis gas converts to methanol in the methanol synthesis reactor; In addition, the water gas shift reaction takes place:

CO + 2H ₂ ^ CH ₃ OH

C02 + 3 H ₂ ^ CH ₃ OH + H ₂ O

CO + H20 ^ C02 + H2 The reactions mentioned are equilibrium-limited and only a small part of the synthesis gas is converted. The conversion of carbon monoxide is depending on

Conditions and gas composition approximately at 30%.

In other words, the subject of the present invention is an improved reactor connection for the synthesis of ethanol from synthesis gas. By the

Vorschschaltung a Methanolsynthesereaktors before a Ethanoldirektsynthesereaktor the total synthesis gas sales can be increased because a part of the

Synthesis gas is converted in the methanol synthesis reactor to methanol. In the context of the present invention, the space-time yield in the ethanol direct synthesis can be increased in comparison to known processes. Of the Ethanol direct synthesis reactor can therefore be formed significantly smaller than in conventional methods for ethanol direct synthesis. By reducing the Ethanoldirektsynthesereaktors can at the same synthesis gas sales

Investment costs can be saved or can be increased with the same investment costs of synthesis gas sales and thus the energy efficiency of a corresponding system.

In principle, for processes which comprise a conversion of synthesis gas, it is known to re-supply unreacted components to a corresponding reaction in a synthesis reactor, that is to say to use recycle streams. However, this requires the most selective separation of the components to be recycled downstream of the synthesis reactor. In this case, inertly behaving components should predominantly not be contained in a corresponding recycle stream, since otherwise they could accumulate in a cycle formed by the recycle. Because typically but comparatively large amounts of unreacted

Components downstream of a synthesis reactor must be in one

corresponding separation very large volumes of gas can be processed. In addition, the separation of only the components to be recycled is often expensive. For example, in the present case downstream of the ethanol direct synthesis reactor, amine scrubbing to remove carbon dioxide, drying and cryogenic separation to remove methane are required. All separation processes are to be interpreted in the case of poorer overall conversion for higher, with better overall conversion, however, for lower gas volumes. Because in the context of the present invention, a better overall conversion is achieved, and thus the downstream of the

Ethanoldirektsynthesereaktors to be processed residual amounts of synthesis gas are smaller, a corresponding separation is therefore easier.

In this way, in addition to the advantage of the small and inexpensive executable Ethanoldirektsynthesereaktors the advantage that the separators used can be made smaller and cheaper. Due to the better overall conversion of the synthesis gas ultimately remains a smaller amount of unreacted components downstream of the

Ethanol direct synthesis reactor. Therefore, here is a smaller amount of gas separation technology to work. Since the methanol synthesis, but also the ethanol direct synthesis, which is used in the present invention, are clearly exothermic, a particularly advantageous temperature control can be achieved by using a smaller Ethanoldirektsynthesereaktors with upstream methanol synthesis reactor instead of only a larger synthesis reactor, since each heat individually and Also downstream of the respective synthesis reactor can be discharged. This is reflected in an even higher efficiency of the synthesis reactors again and also in reduced costs, since, for example, the pipes as

Synthesis reactors used tube bundle reactors can each be optimally designed and tempered.

In the context of the ethanol direct synthesis used in the present invention, which can be carried out as explained above, methanol is formed as a by-product and is therefore present in a component mixture which can be taken from the ethanol direct synthesis reactor. Further methanol in this component mixture is methanol from the methanol synthesis reactor, which was not reacted in the ethanol direct synthesis reactor. Corresponding methanol can therefore from the

Ethanoldirektsynthesereaktor removed component mixture can be separated. To increase the ethanol yield, this methanol can the

Ethanoldirektsynthesereaktor be fed back. As mentioned, depending on the catalyst used, a portion of the methanol formed in the ethanol direct synthesis reactor and the methanol present in the inlet stream of the ethanol direct synthesis reactor are converted to ethanol and optionally higher alcohols. Alternatively, the methanol can also be recovered as a product. The present invention provides in this variant a process for the combined production of ethanol and methanol. In contrast to known methods with only one Ethanoldirektsynthesereaktor while the gas volume to be processed in the separation is significantly reduced in each case, the separation thus easier and less expensive. Advantageously, from the component mixture of the

Ethanoldirektsynthesereaktor one or more by-products of the methanol and / or the ethanol direct synthesis and / or one or more unreacted components of the synthesis gas separated. This is advantageous for the reason mentioned several times, because reduced volumes have to be processed at this point due to the improved overall conversion. The or at least one of the further by-products and / or the or at least one of the further unreacted components of the synthesis gas can, depending on the usability, at least partly in the process, ie in the

Methanol synthesis reactor or the ethanol direct synthesis reactor, recycled and used there. The use can be material, i. in a process stream whose components are converted to methanol or ethanol, but also energetically, for example by burning methane done. Overall results in the

Under the present invention, the possibility of parts of a downstream of the

Ethanol direct synthesis reactor existing gas stream to recycle without that inert components accumulate excessively in a corresponding circuit.

In particular, in the case of using one of the methods explained below for providing the synthesis gas, is returned to the methane, optionally with traces of hydrogen and carbon monoxide, it may also be advantageous if downstream of the or the ethanol direct synthesis reactors carbon monoxide using a water gas shift to Part is converted to carbon dioxide. This can be done before or after an appropriate separation and also in a separate

Multicomponent mixture with, for example, hydrogen, carbon dioxide and / or methane. In this way, material problems can be avoided by excessive carbon monoxide. This is, for example, what is known as metal dusting, that is to say a form of high-temperature corrosion, which may occur at, for example, about 300 to 850.degree. Corresponding measures are therefore advantageously taken when a preheating of a corresponding gas mixture is made to the temperatures mentioned. Advantageously, therefore, the carbon monoxide is partially converted in the component mixture using a Wasserergasshift to carbon dioxide.

The process used in the context of the present invention may in particular also comprise the provision of the synthesis gas by means of suitable reactions.

In particular, in the context of the present invention, steam reforming, dry reforming, autothermal reforming and partial oxidation can be used. In particular, a steam reforming with

Carbon dioxide import into and / or downstream of the reforming take place. As regards the abovementioned methods, reference should be made to relevant specialist literature such as the article "Gas Production "in Ullmann's Encyclopaedia of Industrial Chemistry, published online December 15, 2006, DOI: 10.1002 / 14356007.a12_169., Pub2, and steam reforming and dry reforming differ, in particular, from the one used

Steam quantity, which is more than twice the amount of carbon used in the steam reforming. In dry reforming, the amount of steam used is significantly lower. Combinations of these reactions are also possible, such as the parallel connection of steam reforming and partial oxidation or the sequential interconnection of steam reforming and autothermal reforming. In this way, a synthesis gas with optimum composition for the present invention can be provided.

An appropriate provision of the synthesis gas advantageously also comprises the treatment and / or conditioning of the synthesis gas and / or an insert used to provide the synthesis gas, for example by desulfurization, compression, heat integration, the condensation of process water and / or carbon dioxide separation. Also, such steps help to provide a synthesis gas having optimum composition for the present invention. An appropriate provision of the synthesis gas advantageously also comprises the treatment and / or conditioning of the synthesis gas and / or an insert used to provide the synthesis gas, for example by desulfurization, compression, heat integration, the condensation of process water and / or carbon dioxide separation. Also, such steps help to provide a synthesis gas having optimum composition for the present invention.

An appropriate synthesis gas of suitable composition has

for example, a stoichiometric number of two or more, in particular 2 to 5, for example from 2.5 to 3.5 or from 3 to 4, on. The stoichiometric number SN is calculated from the mole fractions x of hydrogen, carbon dioxide and

Carbon monoxide to SN = (x H2 - x CO2) / (x CO + x CO2). The synthesis gas may in addition to hydrogen and carbon monoxide in particular also 0 to 20 mole percent carbon dioxide. The methane content can be up to 10 or up to 20 mole percent. Further components are advantageously at most 10 mole percent, contain at most 5 mole percent or at most 1 mole percent. The stated stoichiometric number range and the stated contents are influenced by feeds, returns and the like. The values given apply to the synthesis gas supplied to the methanol synthesis reactor and the corresponding ones

Components supplied to the ethanol direct synthesis reactor. Downstream of syngas production, other stoichiometric numbers may also be present. Using such a synthesis gas, particularly high yields can be ensured in the context of the present invention. The ethanol direct synthesis in the context of the present invention is carried out catalytically, in particular as explained above. The ethanol direct synthesis reactor (s) are therefore designed for catalytic ethane direct synthesis using a rhodium, manganese, ruthenium, iron, palladium, platinum or any combination of said catalyst and optionally one or more other materials.

The present invention also extends to a plant for the production of ethanol from synthesis gas, with an ethanol direct synthesis reactor equipped with a catalyst suitable for direct conversion of carbon monoxide

Hydrogen and / or formed of carbon dioxide with hydrogen to ethanol as the main product. According to the invention, a methanol synthesis reactor is provided, which is equipped with a catalyst which is designed to react carbon monoxide with hydrogen and / or from carbon dioxide with hydrogen to methanol as the main product. In addition, means are provided which are adapted to

First supply synthesis gas to the methanol synthesis reactor and a the

Methanol synthesis reactor taken component mixture at least partially unseparated the Ethanoldirektsynthesereaktor.

Advantageously, a corresponding system for implementing a method is set up, as has been explained above, and has corresponding means. The features and advantages explained above are therefore expressly referred to.

The invention will be explained in more detail below with reference to the accompanying drawings, which illustrate an embodiment of the invention and its technical background in more detail. Brief description of the drawings

FIG. 1 illustrates a method according to an embodiment of the invention.

Detailed description of the drawings

FIG. 1 shows a method according to an embodiment of the invention

illustrated and generally designated 100. With 1 to 4 are both process steps as well as used for their realization technical

Facilities called. The explanations regarding FIG. 1 thus relate to a corresponding installation in the same way.

In process 100, a hydrocarbon-rich feed stream a is fed to one or more synthesis reactors 1 for the production of synthesis gas or other technical equipment and corresponding process steps.

As already mentioned, in the context of the present invention, for example, a steam reforming, a dry reforming, an autothermal reforming and a partial oxidation can be used to provide synthesis gas. Also, combinations of these reactions are possible, such as the

Parallel connection of steam reforming and partial oxidation or the sequential interconnection of steam reforming and autothermal reforming. A corresponding provision of the synthesis gas, as also mentioned, advantageously also comprises the conditioning and / or conditioning of the

Synthesis gas and / or one used to provide the synthesis gas use, for example, by desulfurization, compression, heat integration, the condensation of process water and / or carbon dioxide separation. All explained method steps can also be used in the context of the method 100. In addition to the feed stream a, other material streams, for example steam or oxygen, can also be used as required.

A synthesis gas stream b is provided, which is fed to a methanol synthesis reactor 2. For technical details regarding the methanol synthesis reactor 2, in particular the reaction conditions and the catalysts used, reference is made to the cited technical literature and the above explanations.

The methanol synthesis reactor 2, a stream is removed c containing unreacted components of the synthesis gas of the stream b and methanol and by-products of the methanol synthesis. This is fed, in particular together with a recycle stream d explained below, to an ethanol direct synthesis reactor 3. As mentioned, the ethanol direct synthesis reactor 3 may be adapted for catalytic ethanol direct synthesis using a rhodium, manganese, ruthenium, iron, palladium, platinum or a combination of any of said metals and optionally one or more other catalyst materials. The Ethanoldirektsynthesereaktor 3 leaves a stream e, in addition to ethanol by-products of the ethanol direct synthesis and unreacted components of the synthesis gas or unreacted and reacted components from the stream contains c or d.

In one or more separators 4 downstream of the

Ethanoldirektsynthesereaktors 3, where the stream e is supplied, is separated from this, for example, a methanol-rich stream f, which at least partially executed as a product stream from the process and / or at least partially used as the recycle stream d. In the example shown have the

Stream d and f the same composition. Furthermore, an ethanol-rich stream g and a water-rich stream h can be separated. The one or more separators 4 may operate using known separation principles, for example, distillation, condensing, absorptive, and the like.

Downstream of the one or more separators 5 remains a residual current i, which may still contain, for example, hydrogen, methane, carbon monoxide and carbon dioxide. The carbon monoxide contained in the residual stream i can

For example, be subjected to a water gas shift before or after separation from the residual stream m. All components can, as already explained, separated and used in a suitable manner, for example as recycling streams.

Claims

claims

Process (100) for the production of ethanol from synthesis gas using an ethanol direct synthesis reactor (3) equipped with a catalyst designed to directly convert carbon monoxide with hydrogen and / or carbon dioxide with hydrogen to ethanol as the main product, characterized in that the synthesis gas first one

Methanol synthesis reactor (2), which is equipped with a catalyst for direct conversion of carbon monoxide with hydrogen and / or of

Carbon dioxide is formed with hydrogen to methanol as the main product is supplied, and that the methanol synthesis reactor (2) taken component mixture at least partially unseparated the

Ethanoldirektsynthesereaktor (3) is supplied.

The method (100) of claim 1, wherein one of

Ethanoldirektsynthesereaktor (3) removed component mixture separated methanol and fed back to the ethanol direct synthesis reactor (3).

Process (100) according to claim 2, in which one or more by-products of the methanol and / or the ethanol direct synthesis and / or one or more unreacted components of the synthesis gas are separated from the component mixture from the ethanol direct synthesis reactor (3).

Process (100) according to claim 3, wherein the or at least one of the by-products of the methanol and / or the ethanol direct synthesis and / or the or at least one of the unreacted components of the synthesis gas are at least partly recycled to the process (100).

Method (100) according to one of the preceding claims, in which the

Synthesis gas using steam reforming, in particular with carbon dioxide import into or downstream of the reforming reactor,

Dry reforming, autothermal reforming and / or partial oxidation is provided.

6. The method (100) of claim 5, wherein the provision of the synthesis gas comprises the treatment and / or conditioning of the synthesis gas and / or an insert used to provide the synthesis gas. 7. The method (100) according to claim 6, wherein the preparation and / or

Conditioning includes desulfurization, densification, heat integration, condensation of process water and / or carbon dioxide capture.

8. The method (100) according to one of the preceding, wherein the the

Methanol synthesis reactor (2) supplied synthesis gas and a the

Ethanoldirektsynthesereaktor (3) supplied gas mixture has a stoichiometric number of two or more.

9. The method according to any one of the preceding claims, wherein the

Ethanoldirektsynthesereaktor (3) for the catalytic ethanol direct synthesis under

Use of a rhodium, manganese, ruthenium, iron or a combination of said and optionally one or more other materials

having arranged catalyst. 10. plant (100) for the production of ethanol from synthesis gas, with a

Ethanol direct synthesis reactor (3) equipped with a catalyst suitable for the direct conversion of carbon monoxide with hydrogen and / or from

Carbon dioxide is formed with hydrogen to ethanol as the main product, characterized by a methanol synthesis reactor (2), which is equipped with a catalyst for reacting carbon monoxide with

Hydrogen and / or from carbon dioxide with hydrogen to methanol as

Main product is formed by means which are adapted to first supply the synthesis gas to the methanol synthesis reactor (2) and to supply a component mixture taken from the methanol synthesis reactor (2) at least partly unchanged to the ethanol direct synthesis reactor (3).

1 1 system according to claim 10, which is adapted to carry out a method according to any one of claims 1 to 9.