EP3999483A1

EP3999483A1 - Method and facility for producing a target compound

Info

Publication number: EP3999483A1
Application number: EP20742711.3A
Authority: EP
Inventors: Andreas Meiswinkel; Hans-Jörg ZANDER; Ernst Haidegger
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: US20220234973A1; CN114286809A; CA3147857A1; DE102019119540A1; WO2021009307A1

Abstract

The invention relates to a method (100) for producing a target compound, wherein a paraffin is subjected to an oxidative dehydrogenation process (1) using oxygen, thereby obtaining an olefin, and the olefin is subjected to a hydroformylation process (2) using carbon monoxide, 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. According to the invention, carbon dioxide is formed as a byproduct during the oxidative dehydrogenation process (1), the carbon dioxide is subjected to a dry reformation process (3) at least partly using methane, thereby obtaining carbon monoxide and hydrogen, and the carbon monoxide obtained in the dry reformation process (3) and/or the hydrogen obtained in the dry reformation process (3) is supplied to the hydroformylation process (2). 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.

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, carbon dioxide emissions need to be reduced or prevented entirely. As a potential

On the other hand, the starting compound is available in large quantities of methane, which are currently only very limited for recycling and mostly incinerated. In addition, significant amounts of ethane are often present in the corresponding natural gas fractions.

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 known as ODHE

known. Typically, a carboxylic acid of the same chain length is also formed in the ODH, i.e. acetic acid, as a by-product. However, ethylene can also be produced by the oxidative coupling of methane (OCM).

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-olefins 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.

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 is also possible to use higher hydrocarbons, in particular hydrocarbons having six to eleven carbon atoms. 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.

The hydroformylation reaction in the process just mentioned is carried out over a typical catalyst at 115 ° 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 methods. 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 paraffin, in particular a linear paraffin, further in particular ethane, is subjected to oxidative dehydrogenation with oxygen to obtain an olefin, in particular a linear olefin, further in particular ethylene.

As already mentioned at the beginning, oxidative dehydrogenation is a method known in principle from the prior art. In the context of the present invention, known process concepts can be used for the oxidative dehydrogenation. For example, a method can be used in the oxidative dehydrogenation in the context of the present invention, as described in Cavani et al., Catal. Today 2007, 127, 113. In particular, catalysts containing V, Sr, Mo, Ni, Nb, Co, Pt and / or Ce and other metals can be used in conjunction with silicate, aluminum oxide, molecular sieve, membrane and / or monolith supports. For example, in the context of the present invention, combinations and / or oxides of corresponding metals, for example

MoVTeNb oxides and mixed oxides of Ni with Nb, Cr and V are used. Examples are in Melzer et al., Angew. Chem. 2016, 128, 9019, Gärtner et al., ChemCatChem 2013, 5, 3196, and Meiswinkel, Oxidative Dehydrogenation of Short Chain Paraffines ", DGMK Conference Report 2017-2, ISBN 978-3-941721-74-6, and various patents and patent applications of the applicant.

In addition to the specific composition of the catalysts, especially in the case of the MoVTeNb catalysts mentioned, the specific crystal arrangement is also a key feature for achieving high selectivities with high conversions. Among the known catalysts, the mixed oxide catalysts mentioned have a high one Selectivity and activity in the oxidative dehydrogenation of ethane to ethylene. It is generally accepted that the crystal phase M1 is responsible for the outstanding catalytic performance and selectivity, since it is the only phase that is capable of abstracting hydrogen from the paraffin, which is the first reaction step.

A typical by-product of the oxidative dehydrogenation is essentially the respective carboxylic acid in all process variants, i.e. in the case of the oxidative dehydrogenation of ethane, acetic acid, which may have to be separated off, but may represent a further product of value and typically in contents of a few percent (up to low double-digit percentage range). Also

Carbon monoxide and carbon dioxide are formed in the low percentage range. A typical product mixture for the oxidative dehydrogenation of ethane has, for example, the following mixture proportions (preferred value ranges are in brackets

specified):

Ethylene 25 to 75 mole percent (30 to 60 mole percent)

Ethane 25 to 70 mole percent (30 to 50 mole percent)

Acetic acid 1 to 20 mole percent (5 to 15 mole percent)

Carbon monoxide 0.5 to 10 mole percent (1 to 5 mole percent)

Carbon dioxide 0.5 to 10 mole percent (1 to 5 mole percent)

This and the following information relate to the dry portion of the product mixture, which, depending on how the process is carried out, may also contain water vapor. Further components such as oxygenates, i.e. aldehydes, ketones, ethers etc., can be used in traces, i.e. typically less than 0.5 mol percent,

especially less than 0.1 mol percent in total.

In the context of the present invention, the olefin formed in the oxidative dehydrogenation is subjected to hydroformylation with carbon monoxide and hydrogen to give an aldehyde.

Processes for hydroformylation are also known in principle from the prior art. Lately come with appropriate procedures, as in the following cited literature, typically Rh-based catalysts are used. 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 Ό 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, as potential Hydroformulation catalysts are used, an activity according to this publication according to Rh>Co> Ir, Ru>Os>Pt>Pd>Fe> Ni can be 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 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 one greater than the first carbon number due to the chain extension in the hydroformylation. The

The present invention is described below predominantly with reference to ethane as paraffin and ethylene as olefin, but can in principle also be used with higher hydrocarbons.

In the oxidative dehydrogenation, as mentioned, carbon dioxide is formed as a by-product and the by-product carbon dioxide, which is contained in the above-mentioned contents in a corresponding product mixture, is at least partly subjected to dry reforming with methane to obtain carbon monoxide. Since the carbon dioxide content in a corresponding product mixture is typically in the single-digit percentage range, further carbon dioxide from other sources can be added to the dry reforming at any time in addition to the carbon dioxide from the oxidative dehydrogenation. However, the invention always includes that the carbon dioxide formed as a by-product of the oxidative dehydrogenation is at least partially fed to the dry reforming.

Dry reforming is also a fundamentally known prior art method. Instead of many, reference is made to Haimann, "Carbon Dioxide Reforming. Chemical fixation of carbon dioxide: methods for recycling C0 ₂ into useful products", CRC Press 1993, ISBN 978-0 -8493-4428-2. The

Dry reforming is also known as carbon dioxide reforming. In the Dry reforming converts carbon dioxide with hydrocarbons such as methane. In the process, synthesis gas containing hydrogen and carbon monoxide as well as unreacted carbon dioxide and any hydrocarbons used is formed, as is conventionally produced by steam reforming. In the dry reforming process, the educt steam is to a certain extent replaced by carbon dioxide. In dry reforming, one molecule of carbon dioxide and one molecule of methane are converted into 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 Ό 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 are among the Standard reactions in technical chemistry, such as, 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 0 ₃ or Si0 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 for the dehydration of ethanol or at 30 0 to 400 Ό 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 the oxidative

Dehydrogenation, a downstream hydroformylation process, and a dry reforming before. In the context of the present invention, particular advantages result from the fact that the dry reforming can be carried out with the carbon dioxide as the starting material, which is inevitably formed as a by-product in the oxidative dehydrogenation, and that the remaining components are made up of a product mixture of the oxidative dehydrogenation and components from a product mixture of dry reforming, the latter if necessary after carrying out a water gas shift, without costly cryogenic separation steps in hydroformylation. In particular, unreacted paraffins can entrained in the hydroformylation and then separated more easily, or hydrogen that is formed in the dry reforming can be used for later hydrogenation steps. The unconverted paraffins can be recycled in a simple manner and used again in the reaction insert.

The present invention therefore proposes that the carbon dioxide which is formed as a by-product in the oxidative dehydrogenation is at least partially subjected to the dry reforming with methane to obtain carbon monoxide. In the dry reforming, carbon monoxide and / or hydrogen are obtained, preferably both, and the carbon monoxide obtained in the dry reforming and / or the hydrogen obtained in the dry reforming are in turn at least partly fed to the hydroformylation. The carbon dioxide can be separated off upstream and / or downstream of the hydroformylation. In this way, within the scope of the present invention, there is a particularly advantageous and value-adding use of the carbon dioxide formed in the oxidative dehydrogenation and which cannot be avoided as a by-product. 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 "the carbon dioxide which is formed as a by-product in the oxidative dehydrogenation is at least partially subjected to the dry reforming with methane to give carbon monoxide" does not exclude that the dry reforming is further provided from any source Carbon dioxide can be supplied. This is the case in one embodiment of the present invention.

In a further embodiment of the present invention, the

Dry reforming can be carried out in an electrically heated reactor. This results in the particular advantage of avoiding carbon dioxide emissions from the fire, which ideally reduces the carbon dioxide emissions of the

Entire process can be avoided completely.

As mentioned, in the oxidative dehydrogenation, in particular a carboxylic acid can be formed as a further by-product, in the case of ethane as input in the oxidative dehydrogenation in particular acetic acid. This acetic acid can, together with water of reaction, comparatively easily through a condensation and / or a water wash can be separated from a corresponding product mixture of the oxidative dehydrogenation. Due to its high interaction with suitable solvents or washing liquids, carbon dioxide can also be removed comparatively easily from the product mixture, with known processes for carbon dioxide removal, in particular corresponding washes

(e.g. amine washes) can be used. A cryogenic

Separation is not required, so that the entire process of the present invention, at least including dry reforming and hydroformylation, does not require cryogenic separation steps. Should 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 an amine wash can be further reduced by an optional caustic wash as fine cleaning, 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 refers to a separation or a separation step which, in particular, is at a temperature level above 0 Ό, in particular at typical cooling water temperatures of 5 to 40Ό, in particular from 5 to 25 O, is carried out, possibly also above the 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 -30Ό, in particular above -20TT

A further by-product of the oxidative dehydrogenation is typically unreacted paraffin and carbon monoxide in a corresponding product mixture. These compounds can be converted into the subsequent hydroformylation without problems. Carbon monoxide can be reacted with the olefin together with carbon monoxide from dry reforming. The paraffin will

typically not converted in the hydroformylation. Since heavier compounds with a higher boiling point or a different polarity are formed in the hydroformylation, these can be separated from the remaining paraffin comparatively easily and also non-cryogenically.

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 combination of material flows from the

Dry reforming and oxidative dehydration. The present invention By using the water gas shift, it enables precise 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 a product mixture of the oxidative dehydrogenation can also be taken into account, which is combined with carbon monoxide from the dry reforming for use in the hydroformylation. Using a

The water gas shift downstream of the dry reforming thus enables an exact adaptation to the respective requirements in the 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 formed in the oxidative dehydrogenation), the further olefin, especially propylene, a

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, for example, returned to the oxidative dehydrogenation. 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, so it can initially be a production of ethylene as an olefin from ethane as paraffin in the oxidative dehydrogenation, the ethylene in the hydroformylation to propanal is implemented. 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. For this purpose, raw gas can be used and separated into a methane fraction and a fraction with heavier hydrocarbons, in particular rich in ethane. The methane fraction can

Dry reforming and the fraction with heavier hydrocarbons are fed to the oxidative dehydrogenation. The faction with heavier ones

Hydrocarbons can also be treated further, for example if an essentially pure ethane fraction is to be formed for the oxidative dehydrogenation.

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 olefin that is obtained in the oxidative dehydrogenation can be obtained in a product mixture that also contains carbon dioxide and

Contains carbon monoxide, the carbon dioxide being at least partially separated non-cryogenically from the product mixture of the oxidative dehydrogenation or a subsequent step at a suitable point and being subjected to dry reforming. As mentioned, the carbon dioxide can be separated off both before and after the hydroformylation. The carbon monoxide and the olefin can at least in part be subjected to the hydroformylation without prior separation from one another. 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, at least part of the paraffin can go through the oxidative dehydrogenation and the hydroformylation unreacted. As mentioned in detail above, this part can be separated off downstream of the hydroformylation and returned to the oxidative dehydrogenation. The separation can be carried out directly downstream of the

Hydroformylation, i.e. before any 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, a product mixture from the oxidative dehydrogenation, 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.

This allows for a provision of otherwise required

additional compression steps and corresponding compressors can be dispensed with. The oxidative dehydrogenation is within the scope of the present invention advantageously at a pressure level of 1 to 10 bar, in particular 2 to 6 bar, the dry reforming at a pressure level of advantageously 15 to 100 bar, in particular 20 to 50 bar, and the hydroformylation and the removal of carbon dioxide are advantageously at a pressure level of 15 to 100 bar, in particular 20 to 50 bar, carried out.

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 explained in more detail below with reference to the accompanying drawing, which illustrates a preferred embodiment of the present invention.

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.

Is followed by process steps such as oxidative dehydrogenation, the

When talking about dry reforming or hydroformylation, this should also include the apparatus used in each case 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 the method 100 are an oxidative dehydrogenation, which is designated here as a whole with 1, and a hydroformylation, which is designated here as a whole with 2. The method 100 further includes a

Dry reforming, designated here as a whole with 3.

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

Instead of or in addition to the natural gas flow A, however, a separate methane flow B and an ethane flow C can also be provided. The invention is described again here with reference to ethane as the paraffin insert, but, as mentioned, can also be used with higher paraffins. Furthermore, in the example illustrated here, a steam flow B1 and a carbon dioxide flow B2 are provided from an external source.

The natural gas stream is first subjected to a fractionation 101, in particular in a corresponding column, a methane stream being obtained as the top product and a stream containing the heavier hydrocarbons of the natural gas stream, in particular ethane, being obtained as the bottom product. The top stream is designated here by D, the bottom stream by E. The stream E, which can also contain predominantly or exclusively ethane, is fed to the oxidative dehydrogenation 1 together with a recycle stream F. Mixing with oxygen, which is provided in the form of a material flow G, and with steam, which is provided in the form of a material flow H, is carried out. The vapor of the stream H, like nitrogen of an optionally provided nitrogen stream I, serves as

Diluent or moderator and in this way prevents in particular thermal runaway in the oxidative dehydrogenation 1. In the case of the above-mentioned MoVTeNb mixed metal oxide catalysts in particular, water vapor also has the function of ensuring the catalyst stability

(Long-term performance), and by means of steam is a moderation of the

Catalyst selectivity possible.

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

Condensate stream K formed from condensate separation 103, which predominantly or exclusively contains water and acetic acid, can undergo acetic acid recovery 104 are supplied, in which in particular a water flow M and a

Acetic acid stream N are formed.

The product mixture of the oxidative dehydrogenation 1 freed from condensate is compressed in the form of a stream L in a compressor 105 and then fed to a carbon dioxide removal process designated overall by 106, which can be carried out, for example, using appropriate washes. In the embodiment shown here, a wash column 106a for an amine wash and the regeneration column 106b for that in the wash column 106a are also included

Carbon dioxide-laden amine-containing washing liquid shown. Furthermore, an optional wash column 106c for fine cleaning, e.g. for a lye wash, is shown. As mentioned, the removal and recovery of carbon dioxide through appropriate washes is basically known. It is therefore not explained separately.

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 together with a further stream V (see below).

In the hydroformylation 2, propanal is formed from the olefins and carbon monoxide and hydrogen, which propanal is carried out together with the further components explained in the form of a stream Q from the hydroformylation 2. Ethane, which has not been converted and which can be transferred into the recycle stream F, can optionally be separated off from the stream Q in a separation 108, in particular in the oxidative dehydrogenation 1. This recycle stream F also contains any other substances that may be present which boil more easily than propanal. Alternatives to partition 108 are discussed below, but 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 in particular in the oxidative

Dehydrogenation 1, unreacted ethane and any other substances that may be present can be separated off more easily than propanol and transferred into 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 in separately in the form of a stream R, 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 S from the dehydration 112 is fed to a condensate separator 113 and freed there from condensable compounds, in particular 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 optionally provided as an alternative to the separations 108 and 110, where ethane which has not reacted in the oxidative dehydrogenation 1 can again be separated off and transferred to the recycle stream F. A product stream U formed in the separation 114 can be taken out of the process and used in further process steps, 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.

In the oxidative dehydrogenation 1 unconverted ethane is, as mentioned several times, returned to the oxidative dehydrogenation 1 with the stream F. The dry reforming 3 is optionally followed by a water gas shift 116. A product mixture V formed in each case in the dry reforming 3 or the (optional) water gas shift 1 16, which predominantly or exclusively contains hydrogen and carbon monoxide, is (after an optional hydrogen separation in the pressure swing adsorption 1 1 1) together with the stream P freed of carbon dioxide from the oxidative dehydrogenation 1 supplied to the hydroformylation 3.

Claims

A method (100) for producing an object compound in which a paraffin is subjected to oxidative dehydrogenation (1) with oxygen to obtain an olefin, and in which the olefin is subjected to hydroformylation (2) with carbon monoxide and hydrogen to obtain an aldehyde , wherein 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 one greater than the first carbon number, characterized in that carbon dioxide is formed as a by-product in the oxidative dehydrogenation (1) is that the carbon dioxide is at least partially subjected to a dry reforming (3) with methane to obtain carbon monoxide and hydrogen, and that the carbon monoxide obtained in the dry reforming and / or the hydrogen obtained in the dry reforming is at least partially fed to the hydroformylation (2) becomes.

2. The method (100) according to claim 1, in which the aldehyde is the target compound, or in which the aldehyde is further converted to the target compound.

3. The method (100) according to claim 2, wherein the aldehyde is hydrogenated to an alcohol which has a carbon chain with the second carbon number.

4. The method (100) according to claim 3, wherein the alcohol is an olefin

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

5. 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.

6. The method (100) according to any one of the preceding claims, wherein the methane and the paraffin are separated from natural gas.

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

Carbon monoxide obtained in the dry reforming (3) is obtained in a product mixture which further contains at least hydrogen.

8. The method (100) according to claim 7, wherein the product mixture from the

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

9. The method (100) according to claim 7 or 8, in which 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) without being separated.

10. The method (100) according to any one of the preceding claims, in which the olefin that is obtained in the oxidative dehydrogenation (1) is obtained in a product mixture which also contains carbon dioxide and carbon monoxide, the carbon dioxide at least partially upstream and / or downstream of the

Hydroformylation (2) is separated off and subjected to dry reforming (3), and wherein the carbon monoxide and the olefin are at least partly subjected to hydroformylation (2) without prior separation from one another.

1 1. The method (100) according to any one of the preceding claims, in which at least part of the paraffin the oxidative dehydrogenation (1) and the hydroformylation (2) goes through unreacted, is separated off downstream of the hydroformylation (2) and into the oxidative dehydrogenation (1 ) is returned.

12. The method (100) according to claim 10, wherein the product mixture from the

oxidative dehydration is compressed to a pressure level at which the

Carbon dioxide can be separated off and the hydroformylation (2) carried out, and in which the dry reforming (3) is carried out at a lower pressure level.

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

oxidative dehydrogenation (1) and dry reforming (3) is carried out completely non-cryogenically.

14. Plant for the production of a target compound having means for it

are set up to subject a paraffin with oxygen to an oxidative dehydrogenation (1) to give an olefin and to hydroformylate the olefin with carbon monoxide and hydrogen to give an aldehyde (2) subject, wherein 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 one greater than the first

Carbon number, characterized by means which are set up to form carbon dioxide as a by-product in the oxidative dehydrogenation (1), the

To subject carbon dioxide at least partially with methane to dry reforming (3) to obtain carbon monoxide and hydrogen, and the carbon monoxide obtained in the dry reforming (3) and / or in the

Dry reforming (3) obtained hydrogen at least in part

To feed hydroformylation (2).

15. Plant according to claim 14, which is set up to carry out a method according to one of the preceding claims.