METHOD AND FACILITY FOR PRODUCING A TARGET COMPOUND

Abstract

Disclosed is a method for producing a target compound, in which a first gas mixture includes an olefin having a first carbon number and carbon monoxide, a second gas mixture formed using the first gas mixture and containing the olefin, hydrogen and carbon monoxide, is subjected to conversion steps to obtain a third gas mixture containing a compound with a second carbon number and at least carbon monoxide The conversion includes hydroformylation. The second carbon number is one greater than the first carbon number. Using at least a portion of the third gas mixture, a fourth gas mixture which is depleted in the compound has three carbon atoms, is enriched in carbon monoxide, and is formed using at least a portion of the third gas mixture The carbon monoxide in at least a portion of the fourth gas mixture is subjected to a water gas shift to form hydrogen and carbon dioxide, and that the hydrogen formed in the water gas shift is used in the formation of the second gas mixture.

Claims

1-15. (canceled)

16. A method for producing a target compound comprising: providing first gas mixture comprising an olefin having a first carbon number and carbon monoxide, forming a second gas mixture comprising at least a portion of the first gas mixture, the olefin having the first carbon number, hydrogen, and carbon monoxide, obtaining a third gas mixture comprising a compound having a second carbon number and carbon monoxide, subjecting the third gas mixture to one or more conversion steps, wherein the one or more conversion steps comprise a hydroformylation process, and wherein the second carbon number is one greater than the first carbon number, providing the first gas mixture by using an oxidative coupling of methane, and wherein the first gas mixture comprises ethylene as the olefin having the first carbon number, and methane, ethane and carbon dioxide, and wherein the carbon dioxide is at least partly separated from the first gas mixture or a part of the first gas mixture while leaving the second gas mixture, forming a fourth gas mixture comprising the third gas mixture, wherein the fourth gas mixture contains less of the compound with the second carbon number than the third gas mixture, and wherein the fourth gas mixture is enriched in carbon monoxide in such a way that the carbon monoxide in at least a portion of the fourth gas mixture is subjected to a water gas shift to form hydrogen and carbon dioxide, and wherein the hydrogen formed in the water gas shift is used at least in part to form the second gas mixture, compressing the first gas mixture to a first pressure level, wherein the hydroformylation process is carried out at a second pressure level, wherein the water gas shift is carried out at a third pressure level, and wherein the second pressure level is higher than the first and the third pressure levels.

17. The method of claim 16 wherein, the fourth gas mixture comprises one or more paraffins, the method further comprising: forming a fifth gas mixture in a separation process using at least a portion of the fourth gas mixture, where in the fifth gas mixture has less parafins than the fourth gas mixture and wherein the fifth gas mixture is enriched in carbon monoxide, and feeding the fifth gas mixture at least in part to the water gas shift.

18. The method of claim 17 further comprising: forming a sixth gas mixture during the separation process of the fifth gas mixture wherein the sixth gas mixture has more paraffins and fewer carbon monoxide than the fourth gas mixture, and wherein at least a portion of the sixth gas mixture is used when providing the first gas mixture.

19. The method of claim 16 wherein the conversion steps in addition to the hydroformylation process comprise one or more further conversion steps in which the one or more compounds having the second carbon number comprise the aldehyde formed in the hydroformylation process, and wherein one or more further compounds are formed in one or more further subsequent steps.

20. The method of claim 19 further comprising: forming the fourth gas mixture downstream of the one or more subsequent steps.

21. The method of claim 19 wherein the one or more subsequent steps comprise a hydrogenation process in which the aldehyde is converted with hydrogen to form an alcohol.

22. The method of claim 21 wherein, the first gas mixture contains hydrogen and in which at least a portion of the hydrogen is used in the hydrogenation process.

23. The method of claim 21 wherein, at least one subsequent step comprises a dehydration process converting the alcohol to a second olefin.

24. The method of claim 16 further comprising: adapting a hydrogen quantity formed in the water gas shift to a hydrogen requirement in at least one of the hydroformylation process or the hydrogenation process or combinations thereof.

25. The method of claim 16 further comprising: feeding the olefin having the first carbon number and the carbon monoxide from the first gas mixture to the hydroformylation process, and wherein the olefin having the first carbon number and the carbon monoxide from the first gas mixture are at least partially unseparated from each other in the second gas mixture.

26. The method of claim 16, wherein the method is carried out completely non-cryogenically downstream of the water gas shift, and an oxidative dehydrogenation process, or the water gas shift and the oxidative coupling process.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0099] FIG. 1 illustrates a method according to one embodiment of the invention in the form of a schematic flowchart.

[0100] If reference is made below to process steps, such as the oxidative coupling of methane, the water gas shift or hydroformylation, these are also to be understood to cover the apparatus used in each case for these process steps (in particular, for example, reactors, columns, scrubbing devices, etc.), even if reference is not expressly made thereto. In general, the explanations relating to the method apply to a corresponding installation in the same way in each case.

[0101] The invention is described below using the inventive example of the oxidative coupling to provide the first gas mixture. This requires carbon dioxide separation.

DETAILED DESCRIPTION OF THE DRAWINGS

[0102] FIG. 1 illustrates a method according to a particularly preferred embodiment of the present invention in the form of a schematic flowchart and is designated overall by 100.

[0103] Central process steps or components of the method 100 are an oxidative coupling of methane, which is designated here overall by 1, and a hydroformylation, which is designated here overall by 2. The method 100 further comprises a water gas shift, designated here overall by 3.

[0104] In the example shown, a methane stream A is fed to the method 100 or the oxidative coupling of methane 1. Instead of the methane stream A or in addition to this, a raw natural gas stream B can also be provided. If necessary, the raw natural gas stream B can be prepared by means of any treatment step 101. A correspondingly provided input current is denoted by E for better differentiation. Furthermore, in the example illustrated here, a vapor stream B1 and (optionally) a material stream B2 containing water and/or carbon monoxide are provided from an external source in the example illustrated here.

[0105] The feed stream E, together with a partial stream, designated here by F3, of a recycle stream F (or, as explained below, optionally also together with a recycle stream F2 comprising further components), is fed to the oxidative coupling 1. In this case, mixing with oxygen, which is provided in the form of a material stream C, and optionally with vapor, which is provided in the form of a material stream G, is carried out. The vapor of the material stream G, like nitrogen of an optionally provided nitrogen stream H, serves as a diluent or moderator and in this way prevents in particular a thermal runaway in the oxidative coupling 1. Water can also make a contribution in order to ensure the catalyst stability (long-term performance) and/or to enable a moderation of the catalyst selectivity.

[0106] A reactor used in the oxidative coupling 1 can have a region for performing a post-catalytic steam cracking, as was explained at the outset. A partial stream F4 of the recycle stream F containing ethane can optionally be fed into this region. Alternatively or additionally, it is also possible to feed a separately provided ethane stream I. A feed of propane can also be provided in principle. The ethane stream I and optionally propane and heavier components can also be separated from raw natural gas, the remainder of which is then provided as methane stream A.

[0107] Downstream of the oxidative coupling, an aftercooler 102 is provided downstream of which there is, in turn, a condensate separation 103. A condensate stream K formed in the condensate separation 103, which predominantly or exclusively contains water and optionally further, heavier compounds, can be fed to a facility 104 in which, in particular, a (purified) water stream M and residual stream N can be formed.

[0108] The product mixture of the oxidative coupling 1 freed from condensate, which is referred to here generally as the first gas mixture is combined in the form of a material stream L with a stream V from the water gas shift 3, which is rich in hydrogen and carbon monoxide and optionally contains carbon monoxide and/or water that is not converted in the water gas shift, and optionally further components, and subsequently compressed in a compressor 105 and subsequently fed to a carbon dioxide removal designated as 106 which can, for example, be carried out using corresponding washes. In the embodiment shown here, a scrubbing column 106a for an amine scrubbing and the regeneration column 106b for the amine-containing scrubbing liquid loaded with carbon dioxide in the scrubbing column 106a are shown. An optional scrubbing column 106c for fine purification, for example for a caustic scrubbing, is also shown. As mentioned, carbon dioxide removal by corresponding scrubbing is generally known. It is therefore not explained separately.

[0109] A carbon dioxide stream O formed in the carbon dioxide removal 106 can be fed in particular in purified form to any intended use. It is particularly suitable for subsequent use in further processing methods, since it has a comparatively high concentration of carbon dioxide and a high purity.

[0110] A mixture of components remaining in the form of a material stream P, after the removal of carbon dioxide in the carbon dioxide removal 106, and which is here designated generally as the second gas mixture, contains predominantly ethylene, ethane, hydrogen and carbon monoxide. It is optionally dried in a dryer 107 and then fed to the hydroformylation 2.

[0111] In the hydroformylation 2, propanal is formed from the olefins and carbon monoxide, which together with the further components explained is carried out in the form of a material stream Q from the hydroformylation 2. In this case, unconverted ethane and further light compounds, such as methane and carbon monoxide, which can be converted into the recycle stream F, can optionally be separated off from the material stream Q in a separation 108. Alternatives to separation 108 are explained further below.

[0112] In one of a hydrogenation 109, the propanal can be converted to propanol. The alcohol stream is fed to a further separation 110 optionally provided as an alternative to the separation 108, where components with a lower boiling point can also be separated off and transferred to the recycle stream F.

[0113] The hydrogenation 109 can be operated with hydrogen which is contained in a product stream of the water gas shift 3 and is carried along in the hydroformylation. Alternatively, the separate feeding of required hydrogen in the form of a material stream R is also possible, in particular from a separation of hydrogen in a pressure swing adsorption 111.

[0114] A product stream from the hydrogenation 109 or from the optionally provided separation 110 is fed to a dehydration 112. In said dehydration, propylene is formed from the propanol. A product stream S from the dehydration 112 is fed to a condensate separation 113 where it is freed of condensible compounds, in particular water. The water can be carried out of the process in the form of a water stream T. The water streams N and T can, optionally after a suitable work-up, also be fed again to the process for steam generation. In this way, for example, at least a part of the steam flow B1 can be provided.

[0115] 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, in particular, non-converted ethane and light compounds can also be separated off and transferred to the recycle stream F. A product stream U formed in the separation 114 can be carried out of the process and further process steps, for example for the production of plastics or other further compounds, can be used, as indicated here overall by 115. Corresponding methods are known per se and comprise the use of the propylene from the method 100 as intermediate product or starting product in the petrochemical value chain.

[0116] Non-converted ethane and other light compounds, such as methane and carbon dioxide are recycled, as mentioned several times, in the form of a material stream F. For this purpose, in the embodiment illustrated here, a separation 116 is provided, in which a carbon-monoxide-containing or carbon-monoxide-rich partial stream F1, which is also poorer or richer with respect to other components, is formed. Carbon monoxide in this material stream can be converted into the water gas shift 3 to form further hydrogen. The resulting stream V is fed, as described above, at a suitable point before the hydroformylation.

[0117] A further partial stream F2 formed in the separation 116, which can in particular contain methane and ethane, is guided into the oxidative coupling 1. In this case, a separation 117 can optionally be provided, in which the partial streams F3 and F4 can be formed, which have already been explained above. In particular, methane and ethane can be separated from one another in this way, wherein the methane in the partial stream F3 in the oxidative coupling 1 can be conducted to the reactor inlet and the ethane in the partial stream F4 can be conducted to a reactor zone used for the post-catalytic steam cracking. However, it is also possible in principle to feed the material stream F2 to the reactor inlet without separation 117.

Exemplary Embodiment

[0118] In the context of the present invention, a starting gas mixture was considered as can be provided according to the invention by means of the oxidative coupling of methane, but which can also originate from other sources. According to the invention, carbon monoxide is typically present in an order of magnitude like the olefin (for example ethylene) or even in stoichiometric excess. However, the hydrogen fraction is not sufficient according to the invention to cover the stoichiometric demand for the hydroformylation and any possible subsequent further conversion—as in the case described here of a hydrogenation.

[0119] The following gross equation results for an ideal overall reaction according to one embodiment of the present invention of the proposed integrated process downstream of the provision of the starting gas mixture (hydroformylation, hydrogenation and dehydration):

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

[0120] A targeted and demand-based adjustment of the ratio of hydrogen to carbon monoxide is possible by the use of the water gas shift provided according to the invention as follows:

CO+H.sub.2O.fwdarw.H.sub.2+CO.sub.2  (II)

[0121] Other embodiments of the oxidative coupling can also lead in particular to a low or very low hydrogen content in the product gas of the oxidative coupling. Accordingly, there can also be a corresponding disparity in another gas mixture. Here too, in the context of the present invention, the additional provision of hydrogen is, on the one hand, made possible precisely by the above-mentioned water gas shift reaction. A corresponding provision of further additional hydrogen can moreover take place from other sources, for example by means of classical reforming or from water electrolysis.

[0122] A calculation example based on the oxidative coupling is given below to document the advantages that can be achieved according to the present invention, in which the component fractions required or advantageous for an starting gas mixture are determined in particular.

[0123] The gross equation I indicated above results for an ideal overall reaction of the integrated process after oxidative coupling (hydroformylation, hydrogenation and dehydration).

[0124] The carbon monoxide n.sub.total(CO) and hydrogen n.sub.total (H.sub.2) required by the hydroformylation and hydrogenation reaction cascade is 1 mol of carbon monoxide per 1 mol of ethylene and 2 mol of hydrogen per 1 mol of ethylene. The amount of ethylene in the product stream of the oxidative coupling is n.sub.OCM(C.sub.2H.sub.4), the amount of carbon monoxide is n.sub.OCM(CO) and the amount of hydrogen is n.sub.OCM(H.sub.2).

[0125] After the oxidative coupling, the process gas preferably contains a high proportion of carbon monoxide and a certain proportion of hydrogen. If the ratio of carbon monoxide to hydrogen according to the stoichiometric demand of equation I is now set by a shift reaction according to equation II above, the amount of hydrogen n.sub.Shift(H.sub.2) and simultaneously the same amount of carbon monoxide n.sub.Shift(CO) are used:

n.sub.Shift(H.sub.2)=n.sub.Shift(CO)  (III)

[0126] Any additional demand for CO and H.sub.2 required is optionally covered from an external source, such as a reforming process. The amounts of substance from this external source are hydrogen n.sub.external(H.sub.2) and for carbon monoxide n.sub.external(CO).

[0127] Thus, the CO and hydrogen required by gross equation I are covered as follows:

n.sub.total(CO)=n.sub.OCM(CO)−n.sub.Shift(CO)+n.sub.external(CO)  (IV)

n.sub.total(H.sub.2)=n.sub.OCM(H.sub.2)+n.sub.Shift(H.sub.2)−n.sub.external(H.sub.2)  (V)

[0128] In the shift arrangement, the following amount of hydrogen is thus provided:

n.sub.Shift(H.sub.2)=n.sub.total(H.sub.2)−n.sub.OCM(H.sub.2)−n.sub.external(H.sub.2)  (VI)

[0129] By inserting equation VI in equation IV, taking into account equation III, the CO requirement n.sub.total (CO) results as follows:

n.sub.total(CO)=n.sub.OCM(CO)−[n.sub.total(H.sub.2)−n.sub.OCM(H.sub.2)−n.sub.external(H.sub.2)]+n.sub.external(CO)   (VII)

[0130] According to the stoichiometry of gross equation I, the following applies under ideal conditions:

n.sub.total(CO)=n.sub.OCM(C.sub.2H.sub.4)  (VIII)

n.sub.total(H.sub.2)=2n.sub.OCM(C.sub.2H.sub.4)  (IX)

[0131] Following adjustment, the insertion of equation VIII and IX in equation VII results in the following:

3n.sub.OCM(C.sub.2H.sub.4)=n.sub.OCM(CO)+n.sub.OCM(H.sub.2)+n.sub.external(H.sub.2)+n.sub.external(CO)  (X)

[0132] To avoid an external supply of CO and/or H.sub.2, (n.sub.extern(H.sub.2)=n.sub.extern(CO)=0) therefore, the product gas of the OCM ideally fulfills the following equation:

3n.sub.OCM(C.sub.2H.sub.4)=n.sub.OCM(CO)+n.sub.OCM(H.sub.2)  (XI)

[0133] In this case, the shift reaction according to equation II reliably represents the required ratio between CO and H.sub.2.

[0134] An import of CO and/or H.sub.2 is therefore necessary if the following applies:

3n.sub.OCM(C.sub.2H.sub.4)>n.sub.OCM(CO)+n.sub.OCM(H.sub.2)  (XII)

[0135] An excess of CO and/or H 2 is present, however, if the following applies:

3n.sub.OCM(C.sub.2H.sub.4)<n.sub.OCM(CO)+n.sub.OCM(H.sub.2)  (XIII)

[0136] These considerations are based on idealized assumptions, but may help to derive a preferred range for gas compositions. As a result of the integration of the water gas shift provided according to one embodiment of the invention, the ratio of carbon monoxide and hydrogen can be set as required and flexibly.