EP3999485A1

EP3999485A1 - Method and facility for producing a target compound

Info

Publication number: EP3999485A1
Application number: EP20742714.7A
Authority: EP
Inventors: Andreas Meiswinkel; Hans-Jörg ZANDER; Ernst Haidegger; Isabel KIENDL
Original assignee: Linde GmbH
Current assignee: Linde GmbH
Priority date: 2019-07-18
Filing date: 2020-07-16
Publication date: 2022-05-25
Also published as: WO2021009312A1; US20230146273A1; CN114401939A; DE102019119543A1

Abstract

The invention relates to a method (100) for producing a target compound, wherein an outlet gas mixture is provided in particular by oxidatively coupling methane, said outlet gas mixture containing an olefin, carbon monoxide, carbon dioxide, and optionally hydrogen, and the olefin together with the carbon monoxide and hydrogen in at least one part of the outlet mixture is subjected to a hydroformylation process (2), thereby obtaining an aldehyde. The paraffin and the olefin have a carbon chain with a first carbon number, and the aldehyde has a carbon chain with a second carbon number which is greater than the first carbon number by one. The carbon dioxide contained in the outlet mixture is at least partly separated upstream and/or downstream of the hydroformylation process. According to the invention, at least the separated carbon dioxide is subjected to a dry reformation process (3) at least partly using methane, thereby obtaining carbon monoxide, and the carbon monoxide subjected to the hydroformylation process (2) comprises at least one part of the carbon monoxide obtained in the dry reformation process (3). The invention likewise relates to a corresponding facility.

Description

description

Method and system for establishing a target connection

The present invention relates to a method for producing a target compound, in particular propylene, and a corresponding plant according to the preambles of the independent claims.

The project that led to the present patent application was funded under grant agreement No. 814557 of the European Union's Horizon 2020 research and innovation program.

State of the art

The production of propylene (propene) is described in the specialist literature, for example in the article "Propylene" in Ullmann's Encyclopedia of Industrial Chemistry, 2012 edition. Propylene is conventionally produced by steam cracking (Steam

Cracking) of hydrocarbon feeds and conversion processes in the course of refinery processes. In the latter process, propylene is not used

necessarily in the desired amount and only as one of several

Components formed in a mixture with other compounds. Other

Processes for the production of propylene are also known, but not in all cases, for example in terms of efficiency and yield, are satisfactory.

An increasing demand for propylene is predicted for the future ("propylene gap"), which requires the provision of corresponding selective processes. At the same time, it is important to reduce or even prevent carbon dioxide emissions. As a potential

Feedstock, on the other hand, has large quantities of methane available, which are currently only very limited for recycling and mostly incinerated.

The present invention has the object of providing a process for the production of propylene, which is improved in particular in view of these aspects, but also for the production of other organic target compounds, in particular of

Oxo compounds such as aldehydes and alcohols with a corresponding

Carbon backbone to provide. Disclosure of the invention

Against this background, the present invention proposes a method for

Production of a target compound, in particular propylene, and a corresponding system with the respective features of the independent claims.

Preferred embodiments of the present invention are the subject matter of the dependent claims and the description below.

In addition to the steam cracking processes mentioned above, there are also a large number of different processes for converting hydrocarbons and related compounds into one another, some of which are to be named below as examples.

For example, the conversion of paraffins to olefins of the same chain length by oxidative dehydrogenation (ODH, in the case of ethane also referred to as ODHE) is known. The production of propylene from propane by dehydrogenation (PDH) is also known and is a commercially available and established process. This also applies to the production of propylene from ethylene by olefin metathesis. This process requires 2-butene as an additional starting material.

Finally, there are so-called methane-to-olefin or methane-to-propylene processes (MTO, MTP), in which synthesis gas is first produced from methane and the synthesis gas is then converted into olefins such as ethylene and propylene. Corresponding processes can be based on methane, but also based on other hydrocarbons or carbonaceous

Raw materials such as coal or biomass are operated.

However, ethylene can also be produced by the oxidative coupling of methane (OCM), as is the case in one embodiment of the invention and is explained below.

The present invention is basically suitable for use with all

Processes in which a product mixture is formed which, in addition to an olefin, for example ethylene, also contains carbon dioxide and / or carbon monoxide (which can optionally be converted into one another by a water gas shift) in significant quantities, for example a content of 1 to 30 mol percent, in particular from 1 to 20, from 1 to 15 or from 5 to 10 mol percent. A corresponding gas mixture can also in particular contain methane and / or a paraffin, in particular a paraffin with the same chain length as the olefin. Since it is the basis of the process described here, it is referred to here as the "starting gas mixture". In the following, the oxidative coupling of methane is mainly used as an example of such a process; however, the invention is not limited to this.

According to a particularly preferred embodiment of the present invention, the oxidative coupling of methane is used to provide the starting mixture, so this will first be explained in more detail. The oxidative coupling of methane is described in the literature, for example in J.D. Idol et al., "Natural Gas", in: J.A. Kent (Ed.), "Handbook of Industrial Chemistry and Biotechnology",

Volume 2, 12th edition, Springer, New York 2012.

According to the current state of knowledge, the oxidative coupling of methane comprises a catalyzed gas phase reaction of methane with oxygen, in the case of that of two

Methane molecules each split off one hydrogen atom. Oxygen and methane are activated on the catalyst surface. The resulting methyl radicals first react to form an ethane molecule. A water molecule is also formed during the reaction. With suitable ratios of methane to oxygen, suitable reaction temperatures and the choice of suitable ones

Under catalytic conditions, the ethane is then oxydehydrogenated to ethylene, a target compound in the oxidative coupling of methane. Another water molecule is formed here. The oxygen used is typically completely converted in the reactions mentioned.

The reaction conditions for the oxidative coupling of methane typically include a temperature of 500 to 900 ° C., a pressure of 5 to 10 bar and high space velocities. More recent developments go in particular towards the use of lower temperatures. The reaction can be carried out homogeneously or heterogeneously in a fixed bed or in a fluidized bed. In the oxidative coupling of methane, higher hydrocarbons with up to six or eight carbon atoms can also be formed, but the focus is on ethane or ethylene and possibly also propane or propylene. Especially due to the high binding energy between carbon and

Hydrogen in the methane molecule, the yields in the oxidative coupling of methane are comparatively low. Typically no more than 10 to 15% of the methane used is converted. In addition, the comparatively harsh reaction conditions and temperatures favor the cleavage of these

Bonds are required, including the further oxidation of methyl radicals and other intermediates to carbon monoxide and carbon dioxide. The use of oxygen in particular plays a dual role here. So is the methane conversion from that

Oxygen concentration in the mixture depends. The formation of by-products is linked to the reaction temperature, since the total oxidation of methane, ethane and ethylene preferably takes place at high temperatures.

Although the low yields and the formation of carbon monoxide and

Carbon dioxide can partly be counteracted by the choice of optimized catalysts and adapted reaction conditions, a gas mixture formed during the oxidative coupling of methane contains mainly unconverted methane as well as carbon dioxide, carbon monoxide and water in addition to the target compounds such as ethylene and possibly propylene. Any non-catalytic cleavage reactions that may take place may also contain considerable amounts of hydrogen. In the parlance used here, such a gas mixture is also referred to as a “product mixture” of the oxidative coupling of methane, although it predominantly does not contain the desired products but also the unreacted starting material methane and the by-products just explained.

In the oxidative coupling of methane, reactors can be used in which a catalytic zone is followed by a non-catalytic zone. The gas mixture flowing out of the catalytic zone is transferred to the non-catalytic zone, where it is initially still at the comparatively high temperatures that are used in the catalytic zone. In particular, due to the presence of the water formed during the oxidative coupling of methane, the reaction conditions here are similar to those of conventional vapor cracking processes. Therefore ethane and higher paraffins can be converted into olefins here. Additional paraffins can also be fed into the non-catalytic zone so that the Residual heat from the oxidative coupling of methane can be used in a particularly advantageous manner.

Such a targeted vapor splitting in one of the catalytic zones

downstream non-catalytic zone is also referred to as "post bed cracking". The term “post-catalytic vapor splitting” is also used for this in the following. If it is mentioned below that a starting gas mixture used according to the invention is formed or provided "using" or "using" an oxidative coupling of methane, this information should not be understood to mean that only the oxidative coupling itself is used in the provision got to. Rather, further method steps, in particular one, can also be made from the provision of the starting gas mixture

post-catalytic vapor cracking.

According to particularly preferred embodiments of the present invention, paraffins, in particular ethane, which are separated from any material streams at a suitable point or can be contained in corresponding material streams, can be returned to the post-catalytic vapor splitting process alone or together with other components. The separation, if carried out, takes place on

technically suitable point for separation, i.e. at a position at which separation is particularly inexpensive and in particular non-cryogenic. If it is mentioned below that ethane or another paraffin apart from methane is "returned" to the process, this can in particular mean a return to the post-catalytic vapor splitting. In contrast, methane that is "fed back into the process" is used in particular for the oxidative coupling of methane.

However, recycling can also take place together and in particular together with carbon monoxide in the oxidative coupling as a whole.

The individual technologies are steam reforming and dry reforming, as well as modifications of these, including a downstream water gas shift

Adjustment of the ratio of hydrogen to carbon monoxide is also known.

Hydroformylation is another technology that is used in particular for the production of oxo compounds of the type mentioned at the beginning.

Propylene is typically converted in the hydroformylation, but it can higher hydrocarbons, in particular hydrocarbons with six to eleven carbon atoms, can also be used. The conversion of hydrocarbons with four and five carbon atoms is basically also possible, but of less practical importance. The hydroformylation, in which aldehydes can initially be formed, can be followed by a hydrogenation. Alcohols formed by such a hydrogenation can then be dehydrated to the respective olefins.

In Green et al., Catal. Lett. 1992, 13, 341, a process for the production of propanal from methane and air is described. In the process presented, basically low yields based on methane are recorded. In the process, an oxidative coupling of methane (OCM) and a partial oxidation of methane (POX) to hydrogen and carbon monoxide are carried out, which is then followed by hydroformylation. The target product is the mentioned propanal, which has to be isolated as such. One limitation arises from the oxidative coupling of methane to ethylene, for which only lower conversions and limited selectivities are typically achieved at present. Differences in the Green et al. described method for the present invention are explained below with reference to the advantages achievable according to the invention.

The hydroformylation reaction in the process just mentioned is carried out over a typical catalyst at 115 ° C. and 1 bar in an organic solvent. The selectivity for the (undesired) by-product ethane is in the range from approx. 1% to 4%, whereas the selectivity for propanal should reach more than 95%, typically more than 98%. Extensive integration of

Process steps or the use of carbon dioxide, which is formed in large quantities as a by-product in the oxidative coupling of methane in particular, is not described further here, so that there are disadvantages compared to conventional processes. Because partial oxidation is used as a subsequent step for oxidative coupling in the process, i.e. there is a sequential interconnection, large amounts of unconverted methane from oxidative coupling have to be dealt with in the partial oxidation or separated in a costly manner.

No. 6,049.01 1 A describes a process for the hydroformylation of ethylene

described. The ethylene can in particular be formed from ethane. When In addition to propanal, the target product can also be propionic acid. Dehydration is also possible. However, this publication also does not disclose any further integration and does not disclose any sensible use of the carbon dioxide formed.

Advantages of the invention

Against this background, the present invention proposes a method for

Preparation of a target compound, in particular propylene, in which a starting gas mixture is provided which contains an olefin, in particular ethylene, carbon monoxide and carbon dioxide. The provision of the

Starting gas mixture can in particular include that a paraffin, in particular methane, is subjected to a process in which the components mentioned are formed in the starting gas mixture from precursor or starting compounds. In a particularly preferred embodiment, the process can include subjecting methane to oxidative coupling with oxygen to obtain an olefin, in particular ethylene and the further components mentioned as secondary compounds. The starting gas mixture can in particular also contain methane and a paraffin with the same chain length as the olefin, in particular ethane. The starting mixture typically also contains water. Hydrogen can also be contained in the starting mixture. However, the presence of hydrogen is not a requirement, even if a subsequent one

corresponding starting mixture should be described as containing hydrogen.

The oxidative coupling can, for example, also be carried out without the presence or formation of hydrogen.

As already mentioned at the beginning, the oxidative coupling of methane is a method known in principle from the prior art. In the context of the present invention, for the oxidative coupling of methane on known

Process concepts are used.

In embodiments of the present invention, (essentially) pure methane or natural gas or gas can be used as the methane supplier for the oxidative coupling.

Accompanying gas fractions of different purification stages up to the corresponding raw gas can be used. For example, natural gas can also be fractionated, where, if an oxidative coupling is used, methane in the oxidative

Coupling itself and higher hydrocarbons can preferably be fed into a post-catalytic steam cracking. Oxygen is particularly preferred as the oxidizing agent in a corresponding process. Air or oxygen-enriched air can in principle also be used, but lead to one

Entry of nitrogen into the system. A separation at a suitable point in the process would in turn be comparatively expensive and would have to be carried out cryogenically.

In the embodiments of the present invention in which it is used, a diluting medium, preferably steam, but also, for example, carbon dioxide, can be used in the oxidative coupling, in particular to moderate the reaction temperatures. Carbon dioxide can also (partially) serve as an oxidizing agent. In principle, compounds that are likewise suitable as diluents, such as nitrogen, argon and helium, again require expensive separation. With the current state of technology, however, recycled methane in particular serves as a diluent, which is only converted to a comparatively small proportion.

In embodiments of the present invention, the oxidative coupling can be carried out in particular at an excess pressure of 0 to 30 bar, preferably 0.5 to 5 bar, and a temperature of 500 to 1100.degree. C., preferably 550 to 950.degree. In principle, it is possible to fall back on catalysts known from the specialist literature, see, for example, Keller and Bhasin, J. Catal. 1982, 73, 9, Hinsen and Baerns, Chem. Ztg. 1983, 107, 223, Kondratenko et al., Catal. Be. Technol. 2017, 7, 366-381. Farrell et al., ACS Catalysis 6, 2016, 7, 4340, Labinger, Catal. Lett. 1, 1988, 371, and Wang et al., Catalysis Today 2017, 285, 147.

The conversion of methane in the oxidative coupling in the context of the present invention can be in particular more than 10%, preferably more than 20%, particularly preferably more than 30% and in particular up to 60% or 80%. The particular advantage of an embodiment of the present invention in which an oxidative coupling is used, however, is not primarily in the increased yield, but in the fact that in addition to, in particular, a relatively high relative proportion of carbon monoxide in relation to ethylene in the product mixture of the oxidative coupling, that is, the starting gas mixture used in this embodiment can be utilized. Typical by-products of the oxidative coupling of methane are carbon monoxide and carbon dioxide, which are formed in the low to double-digit percentage range. A typical product mixture of the oxidative coupling of methane exhibits

for example the following mixture proportions:

Hydrogen 0.1 to 10 mole percent

Methane 20 to 90 mole percent

Ethane 0.5 to 30 mole percent

Ethylene 5 to 60 mole percent

Carbon monoxide 0.5 to 30 mole percent

Carbon dioxide 0.5 to 30 mole percent

These details relate to the dry portion of the product mixture, which can also contain water vapor in particular. Further components such as higher hydrocarbons and aromatics can be present in concentrations of typically less than 5 mol percent, in particular less than 1 mol percent, oxygenates - i.e. aldehydes, ketones, ethers, etc. - can be present in traces, i.e. typically less than 0.5 mol percent, in particular less than 0.1 mol percent in the product mixture of the oxidative coupling.

As already mentioned, in addition to the oxidative coupling of methane, other sources can also be used to provide the starting gas mixture.

In the context of the present invention, the olefin is subjected to a hydroformylation with carbon monoxide and hydrogen in at least part of the starting gas mixture to obtain an aldehyde. Carbon dioxide contained in the

Starting mixture is contained, is at least partially upstream and / or downstream of the hydroformylation, ie separated from the starting gas mixture or a part thereof and / or from a product mixture of the hydroformylation or a part thereof. This carbon dioxide is at least partly transferred into the product mixture of the hydroformylation if it is not separated off upstream. Processes for hydroformylation are also known in principle from the prior art. Recently, Rh-based catalysts have typically been used in corresponding processes, as described in the literature cited below. Older processes also use Co-based catalysts.

For example, homogeneous, Rh (I) -based catalysts with phosphine and / or phosphite ligands can be used. These can be monodentate or bidentate complexes. For the production of propanal typically reaction temperatures of 80 to 150 ° C and corresponding

Catalysts used. All of the methods known from the prior art can also be used within the scope of the present invention.

The hydroformylation typically works with a ratio of hydrogen to carbon monoxide of 1: 1. However, this ratio can in principle be in the range from 0.5: 1 to 10: 1. The Rh-based catalysts used can have a Rh content of 0.01 to 1.00 percent by weight, the ligands being im

Excess may be present. Further details are described in the article "Propanal" in Ullmann's Encyclopedia of Industrial Chemistry, 2012 edition. The invention is not restricted by the process conditions mentioned.

In a further process, as described, for example, in the "Hydroformylation" chapter in Moulijn, Makee & van Diepen, Chemical Process Technology, 2012, 235, a pressure of 20 to 50 bar for a Rh-based catalyst and a pressure of 20 to 50 bar for a Co -based catalyst, a pressure of 70 to 200 bar is used. Co also appears to be relevant for hydroformylation in metallic form. Other metals are more or less insignificant, especially Ru, Mn and Fe. The temperature range used in the process mentioned is between 370 K and 440 K.

In the process disclosed in the chapter "Synthesis involving Carbon Monoxide" in Weissermel & Arpe, Industrial Organic Chemistry 2003, 135, mainly Co- and Rh-phosphine complexes are used. With specific ligands, the hydroformylation can be carried out in an aqueous medium and the catalyst can be easily recovered. According to Navid et al., Appl. Catal. A 2014, 469, 357, in principle everyone can

Transition metals, which are capable of forming carbonyls, are used as potential hydroformulation catalysts, an activity according to this disclosure according to Rh> Co> Ir, Ru> Os> Pt> Pd> Fe> Ni being observed.

By-products in the hydroformylation arise in particular through the

Hydrogenation of the olefin to the corresponding paraffin, e.g. from ethylene to ethane, or the hydrogenation of the aldehyde to alcohol, i.e. from propanal to propanol. According to the article "Propanols" in Ullmann's Encyclopedia of Industrial Chemistry, 2012 edition, propanal formed by hydroformylation can be used as the main source of 1-propanol in industry. In a second step, propanal can be hydrogenated to 1-propanol.

In the context of the present invention, the olefin in the starting gas mixture has a carbon chain with a first carbon number and the aldehyde has a carbon chain with a second carbon number which is one greater than the first carbon number due to the chain extension in the hydroformylation. The present invention is described below predominantly with reference to ethylene as an olefin, but can in principle also be used with higher

Hydrocarbons are used.

In general, regardless of the specific way the

Starting gas mixture in the context of the present invention, at least the carbon dioxide separated off in the manner explained is subjected at least in part to dry reforming with methane to obtain carbon monoxide. Since the content of carbon dioxide in a corresponding starting gas mixture depends on it

Production is often only in the single-digit percentage range, additional carbon dioxide from other sources can be added to dry reforming at any time. However, the invention always includes that the carbon dioxide contained in the starting gas mixture, which is separated off upstream and / or downstream of the hydroformylation, is at least partly fed to the dry reforming.

Dry reforming is also a fundamentally known prior art method. Instead of many, Haimann, "Carbon Dioxide Reforming. Chemical fixation of carbon dioxide: methods for recycling CO ₂ into useful." products ", CRC Press 1993, ISBN 978-0-8493-4428-2. The dry reforming is also referred to as carbon dioxide reforming. In the dry reforming, carbon dioxide is converted with hydrocarbons such as methane. Hydrogen and carbon monoxide as well as unconverted carbon dioxide and possibly . The hydrocarbon-containing synthesis gas used is formed, as is conventionally produced by steam reforming. In dry reforming, the starting material steam is, so to speak, replaced by carbon dioxide. In dry reforming, one molecule of carbon dioxide is converted with one molecule of methane to two molecules of hydrogen and two molecules of carbon monoxide The comparatively simple further reaction of the hydrogen formed poses a certain challenge in dry reforming

Carbon dioxide to water and carbon monoxide.

In dry reforming, pressures of up to 40 bar and temperatures of up to 950 ° C are typically used. The dry reforming is

typically using Ni or Co catalysts or bimetallic catalysts comprising Ni and Co carried out. More details are

for example in the articles "Gas Production: 2. Processes" and "Hydrogen: 2.

Production "in Ullmann's Encyclopedia of Industrial Chemistry, 2012 edition, and in the chapter" Synthesis Gas "in Weissermel & Arpe, Industrial Organic Chemistry, 2003, 15. Refinements, in particular for the catalysts mentioned, can also be found, for example, in San-Jose -Alonso et al., Appl. Catal. A, 2009, 371, 54, and Schwab et al., Chem. Ing. Tech. 2015, 87, 347.

As mentioned, in embodiments of the present invention, a

Hydrogenation and dehydration of those formed in the hydroformylation

Components for the manufacture of other products are made.

The hydrogenation of different unsaturated components is a well-known and established technology for the conversion of components with a

Double bond in the corresponding saturated compounds. Typically, very high or complete conversions with selectivities of well over 90% can be achieved. Typical catalysts for the hydrogenation of

Carbonyl compounds are based on Ni, as also for example in the article

"Hydrogenation and Dehydrogenation" in Ullmann's Encyclopedia of Industrial Chemistry, 2012 edition. Noble metal catalysts can also be used especially for olefinic components. Hydrogenations belong to the standard reactions of technical chemistry, as also, for example, in M. Baerns et al., "Example 11.6.1: Hydrogenation of double bonds", Technische Chemie 2006,

439. In addition to unsaturated compounds (meaning olefins in particular), the authors also name other groups of substances, such as, for example, in particular aldehydes and ketones as substrates for a hydrogenation. Low-boiling substances such as butyraldehyde from hydroformylation are hydrogenated in the gas phase. When

Hydrogenation catalysts are used here, Ni and certain noble metals such as Pt and Pd, typically in supported form.

For example in the article "Propanols" in Ullmann's Encyclopedia of Industrial

Chemistry, 2012 edition, describes a heterogeneous gas phase process that is carried out at 110 to 1500 and a pressure of 0.14 to 1.0 MPa with a ratio of hydrogen to propanal of 20: 1. A reduction takes place with excess hydrogen and the heat of the reaction is dissipated by circulating the gas phases through external heat exchangers or by cooling the reactor inside. The efficiency based on hydrogen is more than 90%, the conversion of the aldehyde takes place up to 99.9% and it results

Alcohol yields greater than 99%. Commonly used commercial catalysts include combinations of Cu, Zn, Ni and Cr supported on alumina or kieselguhr. Dipropyl ether, ethane and propyl propionate are mentioned as typical by-products that can be formed in traces. According to the general prior art, the hydrogenation is preferably carried out only with

stoichiometric amounts of hydrogen or only a small amount

Excess hydrogen.

Details for corresponding liquid phase processes are also given in the literature. These are carried out, for example, at a temperature of 95 to 1200 and a pressure of 3.5 MPa. Typically Ni, Cu, Raney Ni or supported Ni catalysts which are reinforced with Mo, Mn and Na are preferred as catalysts. For example, 1-propanol can be produced with a purity of 99.9%. The main problem with purifying 1-propanol is removing water from the product. If, as in one embodiment of the present invention, propanol is dehydrated to propylene, water is one of the factors in this step too Are reaction products, so that no water has to be separated off beforehand. The separation of propylene and water is therefore easy.

The dehydration of alcohols over suitable catalysts to produce the corresponding olefins is also known. In particular, the production of ethylene (from ethanol) is common and gains in connection with the

increasing production quantities of (bio) ethanol in importance. The commercial application has been realized by different companies. For example, reference is made to the already mentioned article “Propanols” in Ullmann's Encyclopedia of Industrial Chemistry and Intratec Solutions, “Ethylene Production via Ethanol Dehydration”, Chemical Engineering 120, 2013, 29. The dehydration of 1- or 2-propanol to propene has so far not been of any practical value. Nevertheless, the dehydration of 2-propanol in the presence of mineral acid catalysts can be carried out very easily at room temperature or above. The reaction itself is endothermic and equilibrium limited. High conversions are favored by low pressures and high temperatures. Typically, heterogeneous catalysts based on Al ₂ O ₃ or SiO ₂ are used. In general, several types of acidic catalysts are suitable, and molecular sieves and zeolites, for example, can also be used. Typical temperatures are in the range from 200 to 250 ° C for the dehydration of ethanol or at 30 0 to 400 ° C for the

Dehydration of 2-propanol or butanol. Due to the

Equilibrium limitation, the product stream is typically separated off

(Separation of the olefin product and also at least some of the water by e.g. distillation) and the stream, which contains unconverted alcohol, is sent to the

Recirculated reactor inlet. This can be very high overall

Selectivities and yields can be achieved.

The present invention proposes as a whole the coupling of a

Hydroformylation process and dry reforming, the

Hydroformylation and dry reforming from components of one

common starting gas mixture are fed, namely on the one hand with an olefin, carbon monoxide and optionally hydrogen and on the other hand with carbon dioxide. Particular advantages arise in the context of the present invention in particular from the fact that the dry reforming with the carbon dioxide as

Starting material contained in the starting mixture can be carried out is, for example, because it is inevitably formed as a significant by-product in the oxidative coupling of methane, and that the remaining

Components from the starting mixture and components from one

Product mixture of dry reforming, the latter if necessary after carrying out a water gas shift, can be used in hydroformylation without complex cryogenic separation steps. In particular, paraffins can be carried along from the starting gas mixture in the hydroformylation and then separated off more easily or hydrogen that is formed in the dry reforming can be used for later hydrogenation steps. In this way, the unconverted paraffins can simply be recycled and used again in the reaction, as already explained above with reference to the oxidative coupling and the post-catalytic vapor splitting.

The present invention therefore proposes that the carbon dioxide, which originates from the starting gas mixture, was separated off upstream and / or downstream of the hydroformylation, and, for example, previously in the oxidative coupling as

By-product had been formed, is at least partially subjected to dry reforming with methane to obtain carbon monoxide. In this way, within the scope of the present invention, there is a particularly advantageous and value-adding use of the carbon dioxide contained in the starting gas mixture and which cannot be avoided as a by-product when the starting gas mixture is provided. The advantages of the invention thus consist in an advantageous use of a (by-product) product of one process in the other and an advantageous use of the products of both processes in a subsequent step. As mentioned, the wording, according to which "at least the separated carbon dioxide at least partly with methane to obtain carbon monoxide, includes the

"Is subjected to dry reforming" does not mean that the dry reforming can be supplied with additional carbon dioxide provided from any desired source. This is the case in one embodiment of the present invention.

By using the present invention, a significant overall improvement in the carbon dioxide footprint can be achieved by using the carbon dioxide in the process (feeding into the dry reforming). The invention enables an increase in the possible yield of products of value in the oxidative coupling by using the carbon monoxide as a reactant in the Hydroformylation. At the same time, in the context of the present invention, the effort in the product purification and decomposition, in particular by the

Avoidance of cryogenic separation steps, reduced. The separation of C2 and C3 components can take place at comparatively moderate temperatures and, if necessary, avoiding drying. Overall, the energy efficiency is improved and large cycles, which are conventionally required due to the limited conversions in the oxidative coupling, are avoided or minimized. Steps that do not add value, such as methanation, are avoided within the scope of the present invention, as is the formation of secondary and

By-products as in other processes for the production of propylene.

In the aforementioned article by Green et al. the synthesis of propanal from methane and air has already been described, with an overall low yield based on methane being reported. In this process, a combination of oxidative methane coupling and partial oxidation is used, followed by one

Hydroformylation. The target product is propanal, which must be isolated as such. Limitations here are the oxidative coupling of methane to ethylene, for which only low conversions and limited selectivities are achieved nowadays. Further integration of process steps or the use of

carbon dioxide produced is in Green et al. not described. The advantages that can be achieved according to the invention are therefore not given here. One in Green et al.

The scheme listed shows the partial oxidation as a downstream unit for oxidative coupling. Because of this sequential interconnection, large quantities of methane have to be dealt with in partial oxidation, while those in oxidative

Coupling cannot be implemented. The present invention overcomes this disadvantage through the parallel connection of an oxidative coupling or, more generally, the provision of the starting gas mixture with the dry reforming, the resulting material flows then being combined in the required ratio.

In Green et al. A dry reforming for the production of hydrogen and carbon monoxide is not mentioned at any point, but merely a return of carbon dioxide in a total recycling for partial oxidation is indicated. It is proposed to use ethylene, carbon dioxide and water cryogenically from one

Separate product stream, so that a methane, carbon monoxide and hydrogen-containing residue remains. This is not feasible in practice because it is a cryogenic separation of carbon dioxide and / or water will lead to a very rapid transfer through solid carbon dioxide or ice.

As mentioned, in a method for providing the

Starting gas mixture, for example in the oxidative coupling, more

By-products are formed. If suitable, for example together with water of reaction, these can optionally be separated from a corresponding product mixture of the oxidative coupling by condensation and / or water washing. Carbon dioxide can also be removed comparatively easily from the product mixture due to its high interaction with suitable solvents or washing liquids, whereby known methods for carbon dioxide removal, in particular appropriate washes (for example amine washes), can be used. The same also applies to a separation downstream of the hydroformylation. A cryogenic separation is not required, so that the entire process of the present invention, at least including the dry reforming and hydroformylation, does without cryogenic separation steps. If subsequent steps require the absence or only a very low residual concentration of carbon dioxide (e.g. due to catalyst inhibition or poisoning), the residual carbon dioxide content after amine scrubbing can be used as fine cleaning with an optional caustic wash

can be further reduced as required.

Any water-containing products obtained in the context of the present invention

Gas mixtures can be subjected to drying at a suitable point in each case. For example, drying can take place downstream of the hydroformylation if, in one embodiment of the present invention, this takes place in the aqueous phase and the hydrogenation downstream of the hydroformylation requires a dry stream as the reaction feed. If this is not necessary for the subsequent process steps, drying does not have to take place until it is completely dry, but water contents can also remain in corresponding gas mixtures, if these are tolerable. Different drying steps can also be provided at different points in the process and possibly with different degrees of drying. The byproducts just mentioned are advantageously separated off completely non-cryogenically and are therefore extremely simple in terms of apparatus and energy consumption. This represents an essential advantage of the present invention compared to processes according to the prior art, which typically require an expensive separation of undesired components in subsequent process steps.

A "non-cryogenic" separation is to be understood as a separation or a separation step which, in particular, is at a temperature level above 0 ° C, in particular at typical cooling water temperatures of 5 to 40 ° C, in particular from 5 to 25 ° C, is carried out, if necessary also above

Ambient temperature. In particular, a non-cryogenic separation in the sense understood here represents a separation without the use of a C2 and / or C3 cooling circuit and it therefore takes place above -30 ° C, in particular above -20 ° C.

The components in a corresponding starting gas mixture are

especially when it comes from an oxidative coupling, typically unreacted methane, a paraffin, especially ethane, and carbon monoxide. These compounds can be converted into the subsequent hydroformylation without problems. Carbon monoxide can be used together with carbon monoxide from the

Dry reforming can be implemented with the olefin. The methane and paraffin are typically not converted in the hydroformylation. There in the

If heavier compounds with a higher boiling point or a different polarity are formed by hydroformylation, these can be separated comparatively easily and also non-cryogenically from the remaining lower-boiling components. Instead of a complete separation, a

Enrichment of certain material flows in corresponding components or a depletion in other components take place. All technologies known to the person skilled in the art can be used here, for example absorptive or adsorptive processes, membrane processes and enrichment or separation steps based on organometallic frameworks.

If it is mentioned here that liquids or gases or corresponding mixtures are rich or poor in one or more components, "rich" is intended to mean a content of at least 90%, 95%, 99%, 99.5%, 99.9 %, 99.99% or 99.999% and "poor" for a content of no more than 10%, 5%, 1%, 0.1%, 0.01% or 0.001% on a molar, weight or volume basis. The term "predominantly" denotes a content of at least 50%, 60%, 70%, 80% or 90% or corresponds to the term "rich". Liquids and gases or corresponding mixtures can also be enriched or depleted in one or more components in the language used here, these terms referring to a corresponding content in a starting mixture. The liquid or the gas or the mixture is "enriched" if at least 1, 1-fold, 1, 5-fold, 2-fold, 5-fold, 10-fold, 100-fold or 1,000-fold content, "Depleted" if at most 0.9, 0, 5, 0.1, 0.01 or 0.001 times the content of a corresponding component, based on the starting mixture, is present. In this sense, a (theoretically possible) complete separation represents a depletion to zero with respect to a component in one fraction of a starting mixture, which therefore passes completely into the other fraction and is present in enriched form. This is also included in the terms "enrichment" and "depletion".

If it is said here that a separation takes place, a mere enrichment of certain material flows in corresponding components or a depletion in other components can take place at any time. All technologies known to the person skilled in the art can be used here, for example absorptive or adsorptive processes, membrane processes and enrichment or separation steps based on organometallic frameworks.

In particular, methane and ethane can, as mentioned, be fed back into the process, in particular into the oxidative coupling used in one embodiment of the present invention at the points mentioned. Ethane does not necessarily need to be in a separate reactor section for the post-catalytic one

Vapor cracks are returned, but can also be returned to the oxidative coupling as a whole without being separated from the methane. The same also applies to remaining carbon monoxide, which can optionally be further oxidized to carbon dioxide in the oxidative coupling.

In a particularly preferred embodiment of the present invention it is therefore provided that from at least part of a product mixture the

Hydroformylation or one following hydroformylation Process step, ie in particular the hydrogenation or dehydration as explained below, by separating at least part of the heavier components, a partial mixture is obtained which, compared to the product mixture of the hydroformylation or the process step following the hydroformylation, contains at least methane and a paraffin, in particular ethane, and optionally carbon monoxide is enriched or is poor in or free of heavier components, "poor" here being understood in particular to mean a content of less than 10, 5, 1, 0.5 or 0.1 mol percent. In one embodiment of the present invention, this partial mixture is returned to the process unseparated and at least in part, the return being carried out in particular in a process step which serves to provide the starting gas mixture. In one embodiment of the present invention, the recycling takes place in a reactor used to carry out an oxidative coupling.

In a particularly advantageous development, the present invention can include energy integration, that is to say a coupling of heat flows for endothermic and exothermic reactions. Exothermic reactions are in particular oxidative coupling, hydroformylation and hydrogenation. In contrast, reforming and dehydration intended to provide additional hydrogen are endothermic reactions. In one embodiment of the present invention in which an oxidative coupling is carried out, the use of the waste heat from this appears to be particularly advantageous for dry reforming, which takes place in a similarly high temperature range of typically more than 800 ° C.

In one embodiment, the dry reforming can take place at approx. 15 to 25 bar, depending on the available methane pressure and preferred operating range.

Subsequent compression can therefore be provided, but this can also take place in a common last compressor stage with the product gas of the oxidative coupling. In this way, a product stream from the oxidative coupling and the dry reforming can be passed together through the amine scrubbing to remove carbon dioxide. Although a larger volume flow has to be processed there in this embodiment, residual amounts of carbon dioxide in the product gas of the dry reforming can also be removed in this way. Residual amounts of carbon dioxide, which would interfere with a cryogenic separation, can, however, in embodiments of the present invention where such cryogenic separation does not take place, may be tolerated. Therefore, optionally provided fine cleaning, for example using a lye wash, can possibly be dispensed with.

In the context of the present invention, the aldehyde formed in the hydroformylation can be the target compound, or in the context of the present invention this aldehyde can be converted further into an actually desired target compound. The latter variant in particular represents a particularly preferred embodiment of the present invention.

In particular, during the conversion of the aldehyde to the target compound, the aldehyde can first be hydrogenated to an alcohol which has a carbon chain with the second carbon number, that is to say the same carbon number as the aldehyde. A corresponding variant of the process is particularly advantageous because for this hydrogen contained in a product mixture of the dry reforming can be used which is already in one upstream of the hydroformylation

The feed mixture is present and can be passed through the hydroformylation.

A content of hydrogen and carbon monoxide in a product mixture of the

In the context of the present invention, dry reforming can be set in particular in a water gas shift of a basically known type. The

Water gas shift can in particular downstream of the dry reforming and

are carried out in particular upstream of the hydroformylation. In particular, the water gas shift takes place before a product stream is combined from the

Dry reforming and and of the starting gas mixture or a remainder thereof after the carbon dioxide has been separated off, if necessary. The present invention enables a precise through the use of the water gas shift

Adaptation of the respective hydrogen and / or carbon monoxide contents to the respective requirements in the hydroformylation or the subsequent hydrogenation.

By means of a corresponding water gas shift, the possible contents of carbon monoxide in the starting gas mixture can also be taken into account, which is combined with carbon monoxide from the dry reforming for use in the hydroformylation. The use of a water gas shift downstream of the Dry reforming enables precise adaptation to the respective

Requirements in hydroformylation.

In the process according to the invention and its embodiments, hydrogen can be fed in at any suitable point, in particular upstream of the optionally provided hydrogenation. In this way, hydrogen is available for this hydrogenation. The feed does not have to take place immediately upstream of the hydrogenation; Rather, hydrogen can also by upstream of the

Hydrogenation present or carried out process or separation steps are fed. Hydrogen can for example also from a partial stream

Separated product stream of dry reforming or formed as a corresponding substream, for example by known separation steps such as pressure swing adsorption.

According to a further embodiment of the present invention, during the conversion of the aldehyde to the actual target compound of the process according to the invention, the alcohol formed by the hydrogenation is dehydrated to a further olefin (based on the earlier olefin contained in the starting gas mixture), the further olefin, in particular Propylene, one

Carbon chain with the mentioned second carbon number, ie the carbon number of the previously formed aldehyde and of the alcohol formed therefrom.

In particular, the alcohol formed in the reaction of the aldehyde can

can be separated comparatively easily from unreacted paraffin. In this way, a return flow of the paraffin can also be formed here non-cryogenically and into which, for example, it can be returned to the oxidative coupling of methane.

As already mentioned several times, in the context of the present invention the first carbon number can be two and the second carbon number three, for example ethylene as an olefin can first be produced from methane in an oxidative coupling, the ethylene being converted to propanal in the hydroformylation becomes. This propanal can then be converted to propanol by hydrogenation and this in turn to propylene by dehydration. In a particularly preferred embodiment, the present invention allows the use of all components of natural gas. Any

Natural gas fractions or raw gas are used, as explained above for the oxidative coupling of methane.

As already mentioned, the carbon monoxide that is obtained in the dry reforming can be obtained in a product mixture which also contains at least hydrogen. This hydrogen can be passed through the hydroformylation and then used in a hydrogenation. As already mentioned, the product mixture from the dry reforming can be subjected to a water gas shift. In particular, the product mixture from the

Dry reforming and / or the product mixture from the water gas shift are at least partially subjected to the hydroformylation without being separated.

Further aspects of the present invention have also already been mentioned in principle. In particular, the carbon dioxide can be at least partially separated non-cryogenically from the starting gas mixture and subjected to dry reforming. The carbon monoxide and olefin in the remainder of the

The starting gas mixture and possibly further components in this can, at least in part, be subjected to the hydroformylation without prior separation

be subjected. As mentioned, a complete non-cryogenic separation of gas mixtures obtained can in principle be achieved within the scope of the present invention. This does not necessarily apply to the aforementioned separation of natural gas into the methane fraction and the fraction with heavier hydrocarbons.

As already mentioned, the starting gas mixture can in particular contain methane and at least one paraffin, with at least some of the methane and the paraffin being able to go through the hydroformylation unconverted. As mentioned in detail above, this part can be separated off and recycled downstream of the hydroformylation. Depending on the expediency, the separation can be carried out directly downstream of the hydroformylation, i.e. before each subsequent hydroformylation

Process step, or one downstream of the hydroformylation

Process step, for example after a hydrogenation or dehydration, but also after any separation or processing steps. In a particularly preferred embodiment of the present invention, the starting mixture, depending on how it is provided, in particular after a

Condensate separation, compressed to a pressure level at which both the

Carbon dioxide from the oxidative dehydrogenation before and / or after

The hydroformylation can be separated off and the hydroformylation can be carried out. Additional intermediate steps can optionally be provided between the separation of carbon dioxide and the hydroformylation upstream and / or downstream thereof. Both procedures are done essentially the same

Pressure level, which means in particular that there is no additional compression between the two and the exact operating pressure of both steps is only obtained from the process-related pressure losses between the two steps.

The pressure level at which the removal of carbon dioxide and the hydroformylation are carried out is preferably the highest pressure level in the

Overall process, which means in particular that the dry reforming is carried out at a lower pressure level than the separation of carbon dioxide and the hydroformylation upstream and / or downstream thereof. In this way you can rely on a provision of otherwise required additional

Compression steps and corresponding compressors can be dispensed with.

In the context of the present invention, the starting gas mixture is advantageously provided at the pressure level specified above for the oxidative coupling of methane, the dry reforming is advantageously carried out at a pressure level of 10 to 80 bar, in particular 15 to 50 bar, and the

Hydroformylation and the removal of carbon dioxide are advantageously carried out at a pressure level of 15 to 100 bar, in particular 20 to 50 bar.

The present invention also extends to a system for establishing a target connection, with respect to which the corresponding independent

Claim is expressly referenced. A corresponding system, which is preferably set up to carry out a method, as previously explained in different configurations, benefits in the same way from the advantages already mentioned above. The invention is first explained in more detail below with reference to the accompanying drawing, which illustrates a preferred embodiment of the present invention. An exemplary embodiment of the invention will then be explained in more detail, which is carried out in particular using the method illustrated in the drawing.

Brief description of the drawings

FIG. 1 illustrates a method according to an embodiment of the invention in the form of a schematic flow chart.

If process steps such as the oxidative coupling of methane, dry reforming or flydroformylation are mentioned below, this should also include the apparatus used for these process steps (in particular e.g.

Reactors, columns, washing facilities, etc.), even if not expressly referred to. In general, the explanations relating to the method apply in the same way to a corresponding installation.

Detailed description of the drawings

In FIG. 1, a method according to a particularly preferred embodiment of the present invention is illustrated in the form of a schematic flow chart and is designated as a whole by 100.

Central method steps or components of method 100 are an oxidative coupling of methane, denoted here as a whole by 1, as well as a

Flydroformylation, denoted overall by 2 here. Furthermore, the method 100 includes dry reforming, denoted here as a whole by 3.

In the example shown, a methane stream A is fed to method 100.

Instead of the methane stream A or in addition to this, however, a

Roherdgasstrom B are provided. The raw gas stream B can, if necessary, be processed by means of any processing steps 101. Partial flows of methane flow A and the raw gas flow are denoted by D and E. Further In the example illustrated here, a steam stream B1 and a carbon dioxide stream B2 are provided from an external source.

The substream E is fed to the oxidative coupling 1 together with a substream F1 of a recycle stream F (or, as explained below, possibly also together with the entire recycle stream F). Mixing with oxygen, which is provided in the form of a material flow C, and optionally with steam, which is provided in the form of a material flow G, is carried out. The vapor of the stream G, like nitrogen from an optionally provided nitrogen stream H, serves as a diluent or moderator and in this way prevents in particular thermal runaway in the oxidative coupling 1.Water can also make a contribution to the catalyst stability (long-term performance) to ensure and / or to allow a moderation of the catalyst selectivity.

A reactor used in the oxidative coupling 1 can provide an area for

Have implementation of a post-catalytic vapor splitting, as explained at the beginning. If necessary, a partial stream F2 of the recycle stream F containing ethane can be fed into this area. Alternatively or additionally there is also one

A separately provided ethane stream I can be fed in. Also one

In principle, supply of propane can be provided. The ethane stream I and possibly propane and heavier components can also be separated from raw gas, the remainder of which is then provided as methane stream A.

Downstream of the oxidative coupling 1, an aftercooler 102 is provided, downstream of which there is in turn a condensate separator 103. An Indian

Condensate stream K formed from condensate separation 103, which predominantly or exclusively contains water and possibly further, heavier compounds, can be fed to a device 104 in which in particular a (purified) water stream M and a residual stream N can be formed.

The product mixture of oxidative coupling 1 freed of condensate, which is generally referred to here as "starting gas mixture", is compressed in the form of a stream L in a compressor 105 and then a total of 106 designated carbon dioxide removal, which can be carried out, for example, using appropriate washes , fed. In the one shown here Design are a wash column 106a for an amine wash and the

Regeneration column 106b for the amine-containing washing liquid loaded with carbon dioxide in washing column 106a is shown. Furthermore, an optional

Wash column 106c for fine cleaning, e.g. for a lye wash, shown. As mentioned, the removal of carbon dioxide through appropriate washing and recovery is known in principle. It is therefore not explained separately. As mentioned several times, a corresponding

Carbon dioxide removal.

A carbon dioxide stream O formed in the carbon dioxide removal 106 can, as explained further below, be passed into the dry reforming 3.

A component mixture which remains in the carbon dioxide removal system 106 after the removal of carbon dioxide and which is in the form of a stream P contains predominantly ethylene, ethane and carbon monoxide. It is optionally dried in a dryer 107 and then fed to the hydroformylation 2.

In the hydroformylation 2, propanal is formed from the olefins and the carbon monoxide, which propanal is carried out together with the further components explained in the form of a stream Q from the hydroformylation 2. In particular, unconverted ethane and other lower-boiling compounds such as methane and carbon monoxide can optionally be separated off from stream Q in a separation 108, and these can be transferred into recycle stream F. Alternatives to the partition 108 are explained below, but the partition 108 is a preferred embodiment.

In a hydrogenation 109, the propanal can be converted to propanol. The alcohol stream becomes a further, alternative to the separation 108 optional

provided separation 1 10 supplied, where lower-boiling components can also be separated and transferred to the recycle stream F.

The hydrogenation 109 can be operated with hydrogen which is contained in a product stream of the dry reforming 3 and which is carried along in the hydroformylation. Alternatively, the required hydrogen can also be fed into Form of a stream R possible, in particular from a separation of

Hydrogen in a pressure swing adsorption 1 1 1.

A product stream from the hydrogenation 109 or the optionally provided separation 110 is fed to a dehydration 112. In this propylene is formed from the propanol. A product stream R from the dehydration 112 becomes one

Condensate separation 1 13 supplied and there freed from condensable compounds, especially water. The water can be carried out of the process in the form of a water stream T. The water flows N and T can, if necessary after a suitable treatment, also be fed back to the steam generation process. In this way, for example, at least part of the steam flow B1 can be provided.

The gaseous residue remaining after the condensate separation 113 is fed to a further separation 114, which is optionally provided as an alternative to separations 108 and 110, where in particular also unreacted ethane and lower boiling compounds can be separated off and transferred into recycle stream F. A product stream U formed in the separation 114 can be carried out from the process and further process steps can be used, for example for the production of plastics or other further compounds, as indicated here overall with 115. A large number of corresponding processes are known per se and include the use of propylene from process 100 as an intermediate product or starting product in the petrochemical value chain.

Unreacted ethane and other light compounds like methane and

As mentioned several times, carbon dioxide is returned to the oxidative coupling 1 in the form of a material flow F. Optionally, a separation 1 17 can be provided in which the partial flows F1 and F2 can be formed.

In particular, methane and ethane can be separated from one another in this way, the methane in substream F1 entering oxidative coupling 1 to the reactor inlet and the ethane in substream F2 being able to be fed to a reactor zone used for post-catalytic steam splitting.

The dry reforming 3 is optionally followed by a water gas shift 116. One in each of the dry reforming 3 or the (optional) water gas shift 1 16 formed product mixture V, which predominantly or exclusively contains hydrogen and carbon monoxide, is freed from carbon dioxide (after an optional hydrogen separation in the pressure swing adsorption 1 1 1) together with the

Stream P from oxidative coupling 1 is fed to hydroformylation 2.

Embodiment

In the context of the present invention, a starting gas mixture was considered as it can in principle be provided by means of the oxidative coupling of methane. This has in particular the component proportions specified above.

As an exemplary composition and as a basis for the following calculation example, the following composition is given:

For an ideal overall reaction of the integrated process proposed according to one embodiment of the present invention downstream of the provision of the starting gas mixture (hydroformylation, hydrogenation and dehydration), the following gross equation results:

C ₂ H ₄ + 2 H ₂ + CO C ₃ H ₆ + H ₂ O (I)

In the starting gas mixture given above, there are therefore in this

Embodiment the two required equivalents of hydrogen are almost available and there is only a slight additional requirement. Of carbon monoxide However, only about 1/3 of the stoichiometric requirement is provided, while at the same time a considerable amount of carbon dioxide is present. If it is now possible to convert this amount of carbon dioxide into carbon monoxide and, if necessary, hydrogen, the stoichiometry of the gross reaction equation can easily be fulfilled.

According to the invention, this can be achieved by the step of dry reforming, in which the following idealized implementation takes place:

CO ₂ + CH ₄ 2 CO + 2 H ₂ (II)

Further reactions also lead to the formation of hydrogen:

H ₂ O + CH ₄ CO + 3 H ₂ (I II) CO + H ₂ OH ₂ + CO ₂ (IV)

If necessary, the ratio of hydrogen to carbon monoxide can be fine-tuned in the optional downstream shift reaction (in equation V from left to right) or reversed shift reaction (in equation V from right to left):

CO + H ₂ O «H ₂ + CO ₂ (V)

Other versions of the oxidative coupling can in particular also lead to a lower hydrogen content in the product gas. Correspondingly, the additional provision of hydrogen by the above-mentioned reactions II to V is also necessary. A corresponding provision can take place e.g. by means of classic reforming.

In order to demonstrate the advantages that can be achieved according to the present invention, a calculation example based on oxidative coupling is given in which, in particular, the component proportions required or advantageous for a starting gas mixture are determined. For an ideal overall reaction of the integrated process after the oxidative coupling (hydroformylation, hydrogenation and dehydration), the gross equation I given above applies.

The following remarks build on the one described above

Embodiment and assume idealized conditions and reactions I to V in a reforming, dry reforming and water gas shift or

Reversed water gas shift off.

The carbon monoxide requirement in the hydroformylation is 1 mol carbon monoxide / 1 mol ethylene. The amount of ethylene in the product stream of the OCM is n _OCM (C ₂ H ₄ ). It is therefore mostly necessary to increase the proportion of carbon monoxide n _OCM (CO) already present in the product gas stream after the OCM. The one needed

_Additional requirement n _addition (CO) of carbon monoxide is n _addition (CO) = n _OCM (C ₂ H ₄ ) - n _OCM (CO) (VI)

The dry _reforming supplies the quantities of carbon monoxide n _DryRef (CO) and of hydrogen n _DryRef (H ₂ ). If the additional demand for carbon monoxide is completely covered by the dry reforming, the following applies according to equation II: n _addition (CO) = ½ n _OCM (CO ₂ ) (VI la) n _addition (CO) = n _DryRef (CO) = n _DryRef (H ₂ ) (VI Ib)

In other words, in the context of the invention, a gas is to be regarded as ideal, which the amounts of CO and defined by the equations VI and VI la

Has carbon dioxide in relation to ethylene. This ratio is thus obtained by inserting equation VI la in equation VI, assuming ideal conversions according to equation II in dry reforming and with a sufficient proportion of hydrogen as in the above-mentioned embodiment.

The following applies to the overall composition: [n (C ₂ H ₄ ) - n (CO)] / n (CO ₂ ) = 0.5 (IIX)

Is also the provision of additional hydrogen n _addition (H ₂ ) by reforming (reforming) according to equation III required for the

Overall reaction I - _i.e. if the quantities n _DryRef (H ₂ ) and n _OCM (H ₂ ) are not sufficient - the following applies: n _addition (H ₂ ) = 2 n _OCM (C ₂ H ₄ ) - n _OCM (H ₂ ) - n _DryRef (H ₂ ) (IX)

In accordance with the stoichiometry of equation III,

Carbon monoxide formed as a by-product: n _{Reform ing} (CO) - 1/3 n _Addition (H ₂ ) (X)

Equation VI has to be expanded: nAddition (CO) = n _OCM (C ₂ H ₄ ) - n _OCM (CO) - n _Reforming (CO) (XI)

Substituting equation X into equation XI gives: n _addition (CO) = n _OCM (C ₂ H ₄ ) - n _OCM (CO) - _1/3 n _addition (H ₂ ) (XII)

Substituting equation IX further into equation XII leads to: n _addition (CO) = n _OCM (C ₂ H ₄ ) - n _OCM (CO) - _1/3 [2 n _OCM (C ₂ H ₄ ) - n _OCM (H ₂ ) - n _DryRef (H ₂ )]

(XIII)

Substituting Equation VII into Equation XIII gives Equation XIV.

½ n _OCM (CO ₂ ) = n _OCM (C ₂ H ₄ ) - n _OCM (CO) - [2/3 n _OCM (C ₂ H ₄ )

- _1/3 n _OCM (H ₂ ) - _1/3 n _DryRef (H ₂ )] (XIV)

Correspondingly, by switching to Equation XV, equation XIV results in the relative amount of carbon dioxide in the product gas stream of the oxidative coupling in the idealized case: [1/3 n _OCM (C ₂ H ₄₎ + 1 / 3N _OCM (H ₂₎ n + _DryRef (H ₂₎ - n _OCM (CO)] / n _OCM (CO ₂₎ = 0.5

(XV) If the ratio according to equations or XV is less than 0.5, there is an excess of carbon dioxide and carbon dioxide must be removed from the process by a corresponding purge flow.

If the ratio is greater than 0.5, the amount of carbon dioxide is insufficient to meet the demand for carbon monoxide and it is either an import of

Carbon dioxide required in the dry reforming step according to equation II or an increase in the proportions of hydrogen and carbon monoxide by

Steam reforming according to equation III and, if necessary, water gas shift according to equation V. As already described, the ratio between hydrogen and carbon monoxide after the dry reforming can in particular by means of a water gas shift

be adapted as required.

Claims

1. Method (100) for producing a target compound, in which a

Starting gas mixture is provided which contains at least one olefin,

Contains carbon monoxide and carbon dioxide, and in which the olefin in at least part of the starting gas mixture to obtain an aldehyde one

Hydroformylation (2), the olefin having a carbon chain with a first carbon number and the aldehyde having a carbon chain with a second carbon number which is one greater than the first

Carbon number, and wherein the carbon dioxide contained in the starting mixture is at least partly separated upstream and / or downstream of the hydroformylation, characterized in that at least the separated carbon dioxide is at least partly with methane to obtain carbon monoxide a

Dry reforming (3) is subjected, and that in the

Carbon monoxide obtained dry reforming is used at least in part in the hydroformylation (2).

2. The method according to claim 1, wherein the provision of the starting gas mixture comprises the oxidative coupling of a paraffin, in particular methane.

3. The method (100) according to claim 1 or 2, wherein the aldehyde from the

Hydroformulation is the target compound, or in which the aldehyde is further converted to the target compound.

4. The method (100) according to claim 3, wherein the aldehyde is hydrogenated to an alcohol having a carbon chain with the second carbon number.

5. The method (100) according to claim 4, wherein the alcohol is an olefin

is dehydrated, which has a carbon chain with the second carbon number.

6. The method (100) according to any one of the preceding claims, wherein the first

Carbon number is two and the second carbon number is three.

7. The method (100) according to claim 2, wherein the methane, that of the oxidative

Coupling is subjected to, is at least partially separated from natural gas and in which at least one paraffin from the natural gas is transferred to a post-catalytic vapor cracking step downstream of the oxidative coupling.

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

Carbon monoxide obtained in the dry reforming (3) in one

Product mixture is obtained which also contains at least hydrogen.

9. The method (100) according to claim 8, wherein the product mixture from the

Dry reforming (3) is subjected to a water gas shift (4).

10. The method (100) according to claim 8 or 9, wherein the product mixture from the dry reforming (3) and / or the product mixture from the water gas shift (4) are at least partially fed to the hydroformylation (2) unseparated.

1 1. The method (100) according to any one of the preceding claims, in which the

Carbon monoxide and the olefin from the starting gas mixture are at least partially subjected to the hydroformylation (2) without prior separation from one another.

12. The method (100) according to any one of the preceding claims, wherein the

Starting gas mixture contains a paraffin, at least part of the paraffin passing through the hydroformylation (2) unconverted, being separated off downstream of the hydroformylation (2), and being used again in the preparation of the starting gas mixture.

13. The method (100) according to any one of the preceding claims, wherein the

The starting mixture is compressed to a pressure level at which the carbon dioxide is separated off and the hydroformylation (2) is carried out, and at which the dry reforming (3) is carried out at a lower pressure level ..

14. The method (100) according to any one of the preceding claims, downstream of the

Provision of the starting gas mixture and the dry reforming (3) is carried out completely non-cryogenically.

15. System for establishing a target connection which is set up for this purpose

To provide starting gas mixture which contains at least one olefin, carbon monoxide and carbon dioxide, and the olefin in at least part of the

To subject the starting gas mixture to hydroformylation (2) to give an aldehyde, the olefin having a carbon chain with a first

Carbon number and the aldehyde has one carbon chain with a second

Having a carbon number that is one greater than the first carbon number, the system also being set up to separate the carbon dioxide contained in the starting mixture at least partially upstream and / or downstream of the hydroformylation, characterized by means which are set up for at least that to subject separated carbon dioxide at least in part with methane to dry reforming (3) to obtain carbon monoxide, and to use at least part of the carbon monoxide obtained in the dry reforming in the hydroformylation (2).