阅读说明：本技术 用于生产一种或多种烯烃的方法和系统 (Methods and systems for producing one or more olefins ) 是由 赫尔穆特·弗里茨 安德烈·迈斯温克尔 马丁·舒伯特 马蒂厄·泽尔胡贝尔 尼科尔·桑德尔 索 于 2020-03-04 设计创作，主要内容包括：本发明涉及一种用于生产一种或多种烯烃的方法(100),其中形成含有氧气和一种或多种链烷烃的反应混合物,并且其中反应混合物中的一部分氧气与一部分所述一种或多种链烷烃通过氧化法反应,以形成一种或多种烯烃,产生工艺气体,其中工艺气体至少含有未反应部分的一种或多种链烷烃和氧气、一种或多种烯烃、一种或多种炔烃、二氧化碳和水。该方法包括将工艺气体或使用至少一部分工艺气体形成的气体混合物部分地或完全地按照给定的顺序进行下列过程：冷凝分离(2)；压缩(3)；氧气和一种或多种炔烃的至少部分去除(4)；和二氧化碳去除(5)的一个或多个阶段；其中氧气和一种或多种炔烃的至少部分去除(4)通过使用含有氧化铜或钌的催化剂进行催化反应而同时发生,并且其中催化反应至少部分地以加氢的形式发生。本发明还涉及一种对应的系统。(The invention relates to a process (100) for producing one or more olefins, wherein a reaction mixture is formed comprising oxygen and one or more paraffins, and wherein a portion of the oxygen in the reaction mixture reacts with a portion of the one or more paraffins by an oxidation process to form one or more olefins, producing a process gas, wherein the process gas comprises at least an unreacted portion of the one or more paraffins and oxygen, the one or more olefins, the one or more alkynes, carbon dioxide and water. The method comprises subjecting a process gas or a gas mixture formed using at least a portion of the process gas, partially or completely in a given order, to the following processes: condensation separation (2); compressing (3); at least partial removal (4) of oxygen and one or more alkynes; and one or more stages of carbon dioxide removal (5); wherein the at least partial removal of oxygen and one or more alkynes (4) occurs simultaneously by performing the catalytic reaction using a catalyst comprising copper or ruthenium oxide, and wherein the catalytic reaction occurs at least partially in hydrogenated form. The invention also relates to a corresponding system.)

1. A process (100) for the production of one or more olefins, wherein a reaction feed containing oxygen and one or more paraffins is formed, and wherein a portion of the oxygen in the reaction feed reacts with a portion of the one or more paraffins by an oxidation process to form the one or more olefins, in particular an oxidative dehydrogenation (1) or an oxidative coupling of methane, to obtain a process gas, which comprises at least an unreacted portion of the one or more paraffins and the oxygen, the one or more olefins, one or more alkynes, carbon dioxide and water, characterized in that the process comprises subjecting the process gas or a gas mixture formed using at least a portion of the process gas, in the order indicated herein, partially or completely to separation by condensation (2), compression (3), At least partial removal (4) of the oxygen and the one or more alkynes and one or more stages of carbon dioxide removal (5), wherein the at least partial removal (4) of the oxygen and the one or more alkynes is carried out simultaneously by catalytic conversion using a catalyst comprising copper oxide or ruthenium, and wherein the catalytic conversion is carried out at least partially in hydrogenated form.

2. The process (100) according to claim 1, wherein the at least partial removal (4) of the oxygen and the one or more alkynes is performed downstream of one or more stages of carbon dioxide removal (5) and upstream of one or more further stages of the carbon dioxide removal (5).

3. The process (100) according to claim 1 or 2, wherein downstream of the at least partial removal of the oxygen and the one or more alkynes, a drying (6) and one or more separation steps (7) are carried out.

4. The process (100) according to any one of the preceding claims, wherein the catalyst containing copper oxide is used and the at least partial removal (4) of the oxygen and the alkyne(s) is at a temperature comprising 180 ℃ to 360 ℃, an absolute pressure of 1 to 30 bar, 1000 to 15000h^-1And a hydrogen to oxygen ratio of 0 to 5.

5. The process (100) according to any one of claims 1 to 3, wherein the catalyst comprising ruthenium is used and the at least partial removal (4) of the oxygen and the alkyne(s) is at a temperature comprised between 120 ℃ and 360 ℃, at an absolute pressure comprised between 1 and 30 bar, between 1000 and 15000h^-1And a hydrogen/oxygen ratio of 0 to 5.

6. The process (100) according to any one of the preceding claims, wherein the at least partial removal (4) of the oxygen and the one or more alkynes is performed by adding hydrogen.

7. The process (100) according to any one of the preceding claims, wherein the at least partial removal (4) of the oxygen and the one or more alkynes is carried out isothermally or adiabatically at least in one step.

8. The process (100) according to any one of the preceding claims, wherein the oxidative dehydrogenation is carried out as an oxidative dehydrogenation of ethane.

9. An apparatus for producing one or more alkenes arranged to form a reaction feed containing oxygen and one or more alkanes and arranged to react a portion of the oxygen in the reaction feed with a portion of the one or more alkanes to form the one or more alkenes by an oxidation process, in particular oxidative dehydrogenation (1) or oxidative coupling of methane, to obtain a process gas, wherein the process gas contains at least an unreacted portion of the one or more alkanes and oxygen, the one or more alkenes, one or more alkynes, carbon dioxide and water, characterized in that the apparatus is configured to subject the process gas partially or completely to one or more stages of condensation separation (2), compression (3), at least partial removal (4) of the oxygen and the one or more alkynes and carbon dioxide removal (5) in the order indicated herein, wherein for the at least partial removal (4) of the oxygen and the one or more alkynes simultaneously by catalytic conversion, a catalyst comprising copper oxide or ruthenium is provided, which catalyst is adapted to catalyze the catalytic conversion at least partially in hydrogenated form.

10. The device of claim 9, configured to perform the method of any one of claims 1 to 8.

Technical Field

The present invention relates to a method for producing one or more olefins and a corresponding plant according to the preambles of the independent claims.

Background

Oxidative Dehydrogenation (ODH) of alkanes having 2 to 4 carbon atoms is basically known. In ODH, the above-mentioned paraffins react with oxygen, especially to form olefins of the same carbon number and water.

ODH may be advantageous over more mature olefin production processes such as steam cracking or catalytic dehydrogenation. There is no thermodynamic equilibrium limitation due to the exothermic nature of the reactions involved. ODH can be carried out at relatively low reaction temperatures. In principle, the catalyst used does not need to be regenerated, since the presence of oxygen allows in situ regeneration. Finally, less non-valuable by-products (such as coke) are formed compared to steam cracking.

For further details of ODH, reference is made to the relevant technical literature, such as Duprez, D. and Cavani, F. (eds), Handbook of Advanced Methods and Processes in Oxidation Catalysis From Laboratory to Industry, London 2014: Imperial College Press, Ivas, F. and L pez Nieto, J.M., Light Alkanes Oxidation: Targets learned and Current Challenges (Oxidation of Light Alkanes: achieved Targets and Challenges now), orC.A. et al, Oxidative Dehydrogenation of Ethane: Common Principles and Mechanistic Aspects, ChemCatchem, Vol.5, No. 11, 2013, pp.3196 to 3217.

ODH is also used in the procedures disclosed in, for example, WO 2018/153831A 1, WO 2010/115108A 1, DE 102005000798A 1 and WO 2015/113747A 1. WO 2015/113747 a1 has disclosed an upstream water separation technique for the catalytic removal of carbon monoxide and oxygen from the product mixture of ODH, which technique is again proposed in WO 2018/153831 a 1.

The invention relates in particular to the production of ethylene by ODH of ethane (ODH-E), but can also be used in other process variants of ODH and in other processes, such as Oxidative Coupling of Methane (OCM), in which processes the problems explained below occur in part in the same or similar manner. In the oxidative coupling of methane, a methane-rich stream and an oxygen-rich stream are fed to a reactor, wherein oxygen in the oxygen-rich stream reacts with a portion of the methane in the methane-rich stream to form higher hydrocarbons, particularly the desired product ethylene, with the formation of water and byproducts. Oxidative coupling of methane is disclosed in WO 2015/081122 A3.

The continuous activity of the catalysts used in ODH, in particular in ODH-E, requires a minimum concentration of oxygen, in particular MoVNbTeO of the type known per se_xA catalyst. In this way, a reduction and thus a loss of catalyst performance can be avoided. For this reason, ODH usually does not undergo complete oxygen conversion and the gas mixture withdrawn from the corresponding reactor contains oxygen. The latter may also occur in other programs, such as in OCM.

In addition, high conversion of ODH results in large amounts of carbon monoxide and carbon dioxide and small amounts of acetylenes as by-products. In particular under industrially relevant reaction conditions, large amounts of the corresponding carboxylic acids of the paraffins used can also be formed as by-products. The corresponding components are therefore advantageously separated from one another or from the desired main product in a separation section or removed by chemical reaction or converted into more easily removable components. The invention relates in particular to the removal of oxygen and alkynes from the corresponding gas mixture. The gas mixtures obtained in OCM may likewise contain the corresponding components and be separated off.

Processes known from other technical fields for removing alkynes from gas mixtures cannot be transferred to ODH or ODH-E, to the extent that they cannot be transferred to similar processes for OCM, for reasons that will be explained in detail below. The invention therefore has the object of indicating measures which allow alkyne and oxygen to be removed in an advantageous manner from gas mixtures obtained in particular by ODH or ODH-E or OCM. Catalytic removal will be used for this purpose, but in a more advantageous manner than the cited prior art.

Disclosure of Invention

On this background, the present invention proposes a process for producing one or more olefins and a corresponding plant having the features of the independent claims. Advantageous embodiments of the invention are the subject of the dependent patent claims and the following description.

THE ADVANTAGES OF THE PRESENT INVENTION

In accordance with the present invention, an optimized sequence for removing undesirable components from a process gas of an oxidation process (e.g., ODH, particularly ODH-E, but also, for example, OCM) is provided to achieve functional, safe and efficient operation with minimal investment costs. The undesired components are oxygen and one or more alkynes. Which alkynes are present depends inter alia on the chain length of the alkane used. In ODH-E and OCM is acetylene (acetylene). For simplicity, the term "alkyne" will be used hereinafter even if there are multiple alkynes (alkynes). Furthermore, the following always refers to "removing" oxygen and one or more alkynes, even if these components are removed only to a certain extent, in particular a major portion, i.e. in particular more than 90%, 95% or 99%. (all percentages used herein may refer to mole fraction, mass fraction, or volume fraction). Aspects of the invention also relate to the use of specific catalysts and the configuration of specific catalytic conditions, which are particularly suitable for the purposes explained in connection with oxidation processes such as ODH or ODH-E or OCM, in which the hydrogenation is carried out at least partially according to the invention.

In the following, the positioning or arrangement of the oxygen and alkyne removal steps in the corresponding separation sequence carried out according to the invention is described first, followed by the catalyst used according to the invention and the corresponding catalytic conditions. It should be expressly emphasized that the features specified as optional or advantageously provided do not necessarily form part of the invention, and that the invention can also be referred to merely as features specified in accordance with the invention.

By positioning the oxygen and alkyne removal steps according to the invention, the invention particularly contemplates the introduction of an oxygen-containing gas into the amine scrubber, as is commonly used for the removal of carbon dioxide from process gases of ODH or ODH-E or OCM, poses a considerable risk for the long-term operability of such process units, since undesirable side reactions may occur there as a result of the introduction of oxygen. The same generally applies to chemical carbon dioxide scrubbing, for example also to the amine scrubbing which is generally used.

The present invention also contemplates that by positioning the oxygen and alkyne removal steps according to the present invention, a certain degree of concentration and partial pressure increase is beneficial for alkyne removal. Since the alkyne is only present at the reactor outlet in a relatively low concentration, i.e. in the order of 100 to 200ppm volume fraction, a certain degree of concentration and partial pressure increase is advantageous. In contrast, the presence of large amounts of water is disadvantageous, since this may lead to further side reactions.

Basically, it should be noted that during the separation sequence for the production of ethylene from the process gas from ODH-E (process variants for the conversion of higher paraffins by ODH and OCM are affected in the same way), if not properly removed, a gradual enrichment of oxygen in the separation sequence occurs, which at some point leads to a flammable mixture. The present invention also takes this into account by locating the oxygen and alkyne removal steps according to the present invention. It is advantageous to perform the oxygen removal at a point in the separation sequence where the critical oxygen content has not been reached.

Due to other by-products present in the process gas, it is expected that the chemical reaction of the alkyne during its removal will produce a further component separated from the ethylene or other alkene. Thus, the positioning of the oxygen and alkyne removal steps according to the invention ensures that these components can be separated in a further separation sequence without much additional effort.

Finally, in order to obtain as high an energy efficiency as possible, it is advantageous to perform the oxygen and alkyne removal at process gas conditions close to the point of the catalytic reaction most favorable for oxygen and alkyne removal. This can be ensured by positioning the oxygen and alkyne removal step according to the invention.

None of the known hydrogenation concepts in steam cracking processes, applicable to ODH-E or OCM, meet the above requirements, but these requirements can be met by the positioning of the oxygen and alkyne removal step carried out according to the present invention. However, the same applies to the process proposed in WO 2010/115108 a1, in which oxygen is removed directly downstream of the ODH reactor in a separate reactor in which a hydrogenation catalyst is provided, by means of which, for example, alkynes can also be hydrogenated.

Positioning the oxygen and alkyne removal steps according to the invention in the manner explained allows the products formed in the reaction apparatus to be separated together with the main product (ethylene in the case of ODH-E or OCM) and the components present in the other process gases without additional constructive effort. For this purpose, processes or process steps known per se, such as amine or alkaline washing, are used, operating in an aqueous medium and are therefore not affected by the water formed in the oxygen and alkyne removal step.

The arrangement of the oxygen and alkyne removal step downstream of the aqueous condensate separation and process gas compressor carried out according to the invention exhibits particular advantages over the initially cited WO 2018/153831 a1, for example, in comparison with WO 2010/115108 a 1. In a corresponding arrangement, a high partial pressure of the components to be converted and a compact design of the reaction apparatus for removing oxygen and alkynes can be achieved.

At the same time, at the proposed position according to the invention, a sufficient oxygen concentration to form a combustible mixture has not been reached and the initial conditions after the compressor are in a process window favorable for the removal of oxygen and alkynes, as also described below. Thus, the present invention may eliminate the cumbersome security measures that would otherwise be necessary and is more efficient.

The arrangement proposed according to the invention therefore satisfies all the boundary conditions explained above and achieves significant advantages in the system design. The positioning of the oxygen and alkyne removal steps provided by the present invention is particularly advantageous if corresponding conditions cannot be created elsewhere in the corresponding separation sequence or positioning is disadvantageous there.

As mentioned before, specific catalysts, in particular the advantageous catalytic conditions associated therewith for removing one or more alkynes and oxygen from the corresponding gas mixture, are also proposed according to the present invention. As also noted above, other processes known in the art for removing alkynes from gas mixtures are not suitable or readily applicable to ODH or ODH-E.

For example, isothermal feed gas hydrogenation may be performed to remove acetylenes from the process gas of a steam cracking process. In this context, reference is made to technical documents, such as "Ethylene" in Ullmann's Encyclopedia of Industrial Chemistry (2009 online edition) DOI10.2002/14356007.a10 — 045.pub3, and isothermal feed gas hydrogenation, in particular Falqi, f.: the Miracle of petrochemicals, olefins Industry: intensive research on Steam Crackers), Universal-Publishers 2009, ISBN 1-59942-915-2, The Linde Raw Gas Hydrogenation System section, pages 20 to 22.

Isothermal feed gas hydrogenation is carried out in particular after drying of the feed gas and before separation of hydrocarbons having two or three carbon atoms. However, hydrogenation of the fractions formed in the corresponding separations is also possible in principle, for example isothermal hydrogenation of a hydrocarbon atom fraction having two and possibly more carbon atoms after deethanization and before demethanization, or adiabatic hydrogenation of a hydrocarbon atom fraction having two carbon atoms before the ethane and ethylene fractions are formed.

In the steam cracking process or in the downstream steps thereof, the above hydrogenation always takes place in the absence of molecular oxygen and carbon monoxide contents lower than 1%, generally lower than 1000ppm by volume. To selectively remove acetylenes in an ethylene-rich stream, a noble metal catalyst, e.g., a palladium-based catalyst, is typically used. These catalysts may be doped with other noble metals, if necessary. It is also known to use nickel catalysts, however, which are very sensitive to the carbon monoxide content in the matrix and are therefore used only in the case of carbon monoxide contents of the order of a maximum of 50 to 5000ppm by volume.

In summary, it can be concluded that selective hydrogenation catalysts traditionally used in steam cracking processes, such as the above-mentioned noble metal or nickel catalysts, cannot be used in selective hydrogenation processes because of the relatively high oxygen content in the gas mixture from ODH or ODH-E or OCM. The reason for this is that, in particular, the additional hydrogenation of oxygen in the conventional process causes a sharp temperature rise in the catalyst bed due to adiabatic reactions, which greatly accelerates the hydrogenation of ethylene, resulting in a large proportion of product loss. In the worst case, complete conversion of hydrogen and runaway of the reactor can occur.

Furthermore, it is expected that conventional catalysts are either poisoned by water formed during the oxygen reaction and thus have a short service life, or that the formation of undesirable by-products (polymers, so-called green oils) is greatly promoted.

Conventional noble metal catalysts are also generally less tolerant to carbon monoxide, which is also present in gas mixtures from ODH or ODH-E or OCM. Especially, when the carbon monoxide concentration is high and the volume fraction reaches thousands of ppm, the activity is reduced very strongly. Compensation by increasing the temperature can only be achieved to a limited extent without a significant loss of selectivity.

For removing oxygen and alkynes to treat gas mixtures from Fluid Catalytic Cracking (FCC) processes, copper or nickel sulphide catalysts are usually used, which means that it is possible to feed sulphur into the reaction gas, or even continuous sulphiding is required. In general, the use of copper-based catalysts for the removal of oxygen and/or alkynes from gas mixtures from petrochemical processes is also known, for example from US 5,446,232A, US 4,034,062A, US 2,953,608A, US 3,912,789A, US 4,049,743A, US 4,035,433 a and US 2,381,707 a. However, the measures proposed within the scope of the present invention are not known or suggested by this prior art.

As mentioned before, the combined removal of alkyne and oxygen directly at the outlet of the ODH-E reactor is known, for example from WO 2010/115108 a 1. However, the proposed measures are likewise not described.

Nickel or copper sulphide catalysts for the purification of gas mixtures from FCC usually require the continuous addition of sulphur (for example in the form of dimethyldisulphide DMDS) as described above, in order to maintain a constant activity and selectivity. However, for ODH or ODH-E this would mean the addition of new impurities which in turn would contaminate the product. The use of nickel catalysts having a relatively high carbon monoxide content is also of critical importance since volatile nickel carbonyls may be formed.

The catalysts used according to the invention do not have all the disadvantages of the conventional catalysts described above, in particular when used under defined catalytic conditions. The catalyst used according to the invention and, if necessary, the catalytic conditions, in combination with the positioning of the oxygen and alkyne removal step carried out according to the invention, exhibit its advantageous effects. This is why they are used according to the invention at this position of the separation sequence.

In general, in view of the explanation, the present invention proposes a process for producing one or more olefins by forming a reaction feed comprising oxygen and one or more paraffins. In the case of ODH-E, the reaction feed contains essentially ethane as a paraffin, with other paraffins being absent or present only in small amounts. In this sense, methane used in OCM is also a paraffinic hydrocarbon. If ODH of higher alkanes is carried out, these alkanes have in particular 3 or 4 carbon atoms.

Furthermore, in the context of the present invention, a portion of the oxygen in the reaction feed is passed with a portion of the one or more paraffins through an oxidation process, in particular through oxidative dehydrogenation or oxidative coupling to form one or more olefins, obtaining a process gas. Likewise, conversion to ethylene can occur in ODH-E and OCM, which means that only small amounts of other olefins are formed. In higher paraffinic ODH, olefins with the same chain length are preferably formed. The process gas contains at least an unreacted portion of one or more alkanes and oxygen, one or more alkenes, one or more alkynes, carbon monoxide, carbon dioxide, and water. This list is not exhaustive. In particular, the corresponding process gas may also contain the abovementioned by-products, in particular carboxylic acids of the same chain length as the paraffins used.

The process according to the invention comprises subjecting the process gas or a gas mixture formed using at least a portion of the process gas, in the order described herein, partially or completely to one or more stages of condensation separation, compression, at least partial removal of oxygen and one or more alkynes and carbon dioxide removal, wherein the at least partial removal of oxygen and one or more alkynes is carried out simultaneously by catalytic reaction using a catalyst comprising copper or ruthenium oxide. Thus, according to the invention, the catalytic reaction is carried out downstream of the compressor separating the aqueous condensate from the feed gas, but upstream of the carbon dioxide removal unit and the drying unit described below and in particular the cryogenic separation unit. Furthermore, the catalytic reaction is at least partially carried out in a hydrogenation mode.

If in the context of the present invention a catalyst is used which contains copper oxide, this advantageously also contains manganese oxide. By using these catalysts, the advantages of proper positioning, which have been explained in detail above, can be achieved. The oxygen and the alkyne or alkynes are at least partially removed by catalytic reactions, in particular in one process step, i.e. in only one reaction apparatus and/or using only one catalyst or catalyst bed. Thus, the content of oxygen and one or more alkynes is reduced simultaneously.

In the present invention, the at least partial removal of oxygen and one or more alkynes by catalytic reaction is carried out by hydrogenation of oxygen and one or more alkynes, wherein hydrogen may optionally be fed to the corresponding reaction unit. However, embodiments not forming part of the present invention may provide for at least partial oxidative removal of at least a portion of the oxygen, wherein carbon monoxide contained in the respective gas mixture is oxidized by oxygen to form carbon dioxide. Depending on the heat of reaction liberated, an isothermal reaction apparatus or at least a single-stage adiabatic reaction apparatus can be used to remove oxygen and alkynes. In the case of hydrogenation, the amount of hydrogen and/or the temperature level of the optional feed is adjusted in such a way that the simultaneous reaction of oxygen and one or more alkynes proceeds as completely as possible. The desired products of such conversion are in particular further ethylene, ethane, carbon monoxide, carbon dioxide and water, as well as traces of methane, oxygenates and so-called green oils. These components can be easily removed in existing separation steps.

In a variant of the invention, in which the positioning of the removal of oxygen and alkynes after condensation separation and compression according to the invention can provide a multistage carbon dioxide removal, wherein the various stages of carbon dioxide removal can also be carried out upstream of the oxygen and alkynes removal. In other words, at least partial removal of oxygen and one or more alkynes may be performed downstream of one or more stages of carbon dioxide removal and upstream of one or more further stages of carbon dioxide removal.

Advantageously, the drying and the one or more separation steps are carried out downstream of the at least partial removal of oxygen and the one or more alkynes. In one or more separation steps, the components formed during the at least partial removal of oxygen and one or more alkynes can be easily separated in the remaining process gas or the corresponding subsequent mixture without additional equipment components.

In particular, the downstream separation step or steps are designed in such a way that they are not only intended to remove the (by-products) formed during the removal of oxygen and alkynes, which is desired in the present invention, but also other undesired components, such as residual carbon dioxide, residual oxygen and possibly any methane and/or other low-boiling components.

In the context of the present invention, the removal of oxygen and acetylenes in particular creates basic conditions for the safe performance of these further separation steps (cryogenic distillation in particular). The use of these downstream steps also avoids the need to completely remove oxygen upstream. As previously mentioned, the term "removed" herein also means partially removed. The use according to the invention has the particular advantage that no combustible mixture is formed further downstream of the concentrated low-boiling component stream.

In particular, in the context of the present invention, the complete removal of carbon dioxide need not be carried out upstream, but can be carried out by a corresponding downstream separation step.

Optionally, the separation step or at least one of them mentioned can be carried out in a low temperature and/or adsorption mode within the scope of the present invention. In particular, cryogenic distillation may be used, but alternative purification steps, such as pressure swing adsorption, may also be used.

As mentioned above, in the present invention, the process gas or a suitably treated portion thereof or a gas mixture formed using the process gas in which the defined positioning of the oxygen and alkyne removal is carried out is present upstream of the oxygen and/or alkyne removal under particularly favorable conditions. These conditions will be explained below with reference to the advantageous catalytic conditions of the different catalysts.

In particular, complete or almost complete reaction of oxygen and alkynes can be achieved with minimal loss of ethylene and minimal formation of by-products (e.g., green oil and/or carboxylic acids) using the above-described catalysts and applied catalytic conditions. In embodiments of the invention, particularly high stability and service life of the catalyst is achieved. In contrast to WO 2018/153831 a1, the catalytic reaction is at least partially carried out in hydrogenated form, in particular with the addition of hydrogen.

In one embodiment of the invention, a catalyst is used which contains copper oxide, which may also contain, in particular, manganese oxide. In the context of the present invention, catalysts which can advantageously be used comprise in particular from 7 to 11% of copper oxide and from 10 to 15% of manganese oxide. The corresponding catalyst may in particular be supported on a body made of a suitable support material, for example alumina. Further characteristics of the copper oxide containing catalyst include: the catalyst body has different shapes and structures, such as plate-like, ring-like, tricyclic (three-hole) and other common shapes and structures, whereby the shape is chosen to be adapted to the requirements of the corresponding process, e.g. to minimize the pressure drop over the catalytic reactor.

According to the invention, as repeatedly stated, the at least partial removal of oxygen and one or more alkynes comprises catalytic hydrogenation of at least a portion of the oxygen. At least partial removal of oxygen and one or more alkynes is carried out within the scope of the present invention, in particular at a temperature comprised between 180 ℃ and 360 ℃, in particular between 200 ℃ and 250 ℃, further in particular between 220 ℃ and 240 ℃, a pressure comprised between 1 and 30 bar, in particular between 10 or 15 and 25 bar absolute, between 1000 and 15000h^-1In particular 2000 to 5000h^-1More particularly still from 3000 to 4000h^-1Gas Hourly Space velocity (Gas Hourly Space)Velocity, GHSV) and a hydrogen to oxygen ratio of 0 to 5. In particular, in the at least partial conversion of oxygen, the ratio of hydrogen to oxygen used for the hydrogenation of oxygen may be in the range of, for example, 1 to 4 or 2 to 3. In particular, these are the molar ratios under the conditions described above. The pressure used also depends on the positioning of the oxygen and alkyne removal steps, which has been explained many times.

Within the scope of the present invention, it was surprisingly recognized that under at least partial hydrogenation conditions with respect to oxygen, conversion of alkynes also occurs. Thus, by using these conditions and the catalyst used, the oxygen and alkyne can be reacted simultaneously. Without being limited by any of these explanations, one explanation for the reaction may be that the alkyne decomposes over the catalyst at the temperatures used and reacts with oxygen to form carbon monoxide or carbon dioxide. Although an oxygen hydrogenation catalyst is used, a corresponding reaction with the alkyne also occurs.

As an alternative to at least partial hydrogenation, the oxidation of oxygen by reaction with carbon monoxide contained in the product gas can in principle also be carried out, as is mentioned, for example, in WO 2018/153831A 1. Carbon dioxide is formed as a product therein. However, in general, the alkynes present decompose on the catalyst surface, leading to coking, with rapid loss of catalyst activity over time. The present invention avoids this disadvantage by the reaction conditions described above.

In the context of the present invention, it can therefore be surprisingly shown that, when using catalysts containing copper oxide, in particular based on copper oxide and manganese oxide, under suitable reaction conditions, it is also possible to remove alkynes simultaneously without a significant loss of activity over time. The addition of hydrogen can further reduce coking due to the presence of acetylenes. In other words, in the context of the present invention, instead of oxidation conditions, conditions are used which lead to at least partial hydrogenation of the oxygen.

In an alternative arrangement of the invention, a catalyst containing ruthenium is used. In the context of the present invention, catalysts which can advantageously be used in this connection comprise, in particular, from 0.01% to 1% of ruthenium. The corresponding catalyst may in particular be supported on a body made of a suitable support material, for example alumina. Further features include: the catalyst body has different shapes and structures, such as plate-like, ring-like, tricyclic (three-hole) and other common shapes and structures, whereby the shape is chosen to be adapted to the requirements of the corresponding process, such as to minimize the pressure drop over the catalytic reactor.

When a ruthenium-containing catalyst is used, the at least partial removal of oxygen and of the alkyne(s) comprises catalytic hydrogenation, advantageously at a temperature comprised between 120 ℃ and 300 ℃, in particular between 130 ℃ and 170 ℃, at an absolute pressure comprised between 1 and 30 bar, in particular between 10 and 25 bar, between 1500 and 4500h^-1And a hydrogen to oxygen ratio of from 1 to 14, for example from 4 to 10. The pressure used here also depends on the positioning of the oxygen and alkyne removal steps, which has been explained several times.

In the context of the present invention, it has been found that the known ruthenium-containing catalysts also favor the simultaneous hydrogenation of oxygen and alkynes in the present field of application. They exhibit a high resistance to the strong adiabatic temperature rise mentioned at the outset. Ethylene losses below 2% are also tolerable.

In all cases, in the context of the present invention, at least partial removal of oxygen and one or more alkynes may be carried out by adding hydrogen to set reaction conditions suitable for the hydrogenation reaction, or even to avoid slight decomposition of the alkynes during oxidation of carbon monoxide with oxygen, as described above.

As previously mentioned, the present invention is particularly useful in the oxidative dehydrogenation of ethane wherein the composition of the feed mixture and the process gas produced therefrom as previously explained is predetermined.

The invention also extends to an apparatus for producing one or more olefins, with respect to which the corresponding independent patent claims are referenced. With regard to the features and advantages of the apparatus, the apparatus is advantageously arranged to carry out the procedures explained in detail in the above embodiments, with reference to the explanations above.

The present invention will be explained in more detail below with reference to the drawings and examples according to the present invention and comparative examples.

Detailed Description

Figure 1 illustrates a process according to a particularly preferred embodiment of the present invention, which process is generally designated 100. The explanations with respect to the method 100 apply equally to the corresponding apparatus, wherein the process steps shown in fig. 1 are carried out by corresponding apparatus components.

In the process 100, a reaction feed containing oxygen and one or more paraffins is formed and subjected to oxidative dehydrogenation 1 in the form of a material stream a. The process gas formed in the oxidative dehydrogenation is fed at least partly to a condensation separation 2, in which, for example, water and acetic acid are separated in a condensation manner. The corresponding process gas or a part thereof is fed to the condensation separation in the form of process gas stream b.

The process gas removed from the condensate separation and depleted in water and possibly other components is fed in the form of a process gas stream c to a process gas compressor or feed gas compressor 3 and is compressed there to a pressure level of, for example, more than 15 bar. The compressed process gas stream is fed in the form of a material stream d to an at least partial removal 4 of oxygen and alkyne, wherein both alkyne and oxygen are reacted by setting certain reaction conditions. The correspondingly treated process gas is subjected to carbon dioxide separation 5 in the form of a process gas stream e, then to a drying process 6 in the form of a process gas stream f, and finally to one or more further separation steps 7 in the form of a process gas stream g (shown here in highly simplified form). In one or more separation steps 7, one or more fractions h, i are formed and carried out of the process 100.

Basically, the procedure 100 as shown in fig. 1 can be implemented in different ways. In particular, process steps 5 to 7 can be carried out in different arrangements, part of the streams or fractions can be recycled, etc. The embodiments of the present invention are explained repeatedly.

According to example 1, a commercial catalyst consisting of copper oxide and manganese oxide supported on alumina was tested for its suitability for removing oxygen and alkynes from the process gas of ODH or ODH-E. The catalyst was pulverized to 3mm and packed into a tubular reactor having an inner diameter of 29 mm. Glass beads were packed as inert material above the catalyst bed. A 15cm catalyst bed was achieved. The reactor was operated as an insulated tubular reactor and heated by heating tape to compensate for heat loss. A gas mixture having the composition (volume percent) given in table 1A was fed through a mass flow controller:

TABLE 1A

	Gas mixture 1	Gas mixture 2
			Hydrogen gas	0	0.66
Ethylene	35.9	35.9
			Acetylene	0.015	0.015
Ethane (III)	59.1	52.5
			Oxygen gas	0.47	0.47
Nitrogen gas	1.77	7.7
			Carbon monoxide	2.72	2.72

Tables 1B and 1C show that oxygen and acetylene were successfully removed simultaneously for the two gas mixtures listed in table 1A over 250 hours of run time. Between 158.8 hours and 179.2 hours, a switch was made between gas mixtures 1 and 2 according to table 1A, i.e. hydrogen was also added. Thus, tables 1B and 1C both relate to continuous testing.

The reaction conditions used were: gas Hourly Space Velocity (GHSV) of about 3700h^-1The reactor inlet temperature was 230 ℃ and the pressure was 20 bar. The results show that oxygen can be removed by oxidation of carbon monoxide (gas mixture 1 in the absence of hydrogen) and hydrogenation (gas mixture 2). The ethylene loss was very low in each case.

TABLE 1B (gas mixture 1 according to TABLE 1A)

Run time h	4.7	58.6	118.5	140.1	158.8
						Ethylene loss%	1.9	0.15	0.08	0.28	0.05
Oxygen conversion%	100	100	100	100	100
						Conversion of acetylene%	100	100	100	100	100

TABLE 1C (gas mixture 2 according to TABLE 1A)

Run time h	179.2	199.2	226.2	254.1
					Ethylene loss%	0.00	0.00	0.00	0.00
Oxygen conversion%	99.8	100	100	100
					Conversion of acetylene%	100	100	100	100

In comparative example 1, the same test apparatus as in example 1 was used, and the same GHSV was applied. However, only a reactor inlet temperature of 170 ℃ was used. As shown in fig. 2, under these conditions, the catalyst quickly deactivated and the oxygen conversion decreased. Figure 2 shows the test time in hours on the abscissa, relative to the conversion in mole percent on the ordinate. The reaction of oxygen is represented by 201 and the reaction of acetylene is represented by 202.

A sample of a commercially available ruthenium catalyst supported on alumina was tested according to example 2. The spheres (diameter 2 to 4mm) were packed into a 29mm internal diameter tubular reactor. Glass beads are packed as inert material above the catalyst bed. A 20cm catalyst bed was achieved. The reactor was heated by heating tape. The reactor was operated as an insulated tubular reactor. A gas mixture having the composition (volume percent) given in table 2A was fed through a mass flow controller:

TABLE 2A

	Gas mixture
		Hydrogen gas	2.06
Ethylene	34.70
		Acetylene	0.017
Ethane (III)	39.20
		Oxygen gas	0.49
Nitrogen gas	30.65
		Carbon monoxide	2.89

Table 2B shows successful removal of both oxygen and acetylene under different conditions. The pressure set in the reactor was 20 bar.

TABLE 2B

GHSV h-1	2084	4340	4297	2510
					Inlet temperature C	152	150	189	152
Ethylene loss%	1.9	0.7	0.1	0.8
					Oxygen conversion%	99.2	97.7	97.3	96.9
Conversion of acetylene%	100	100	100	100

In comparative example 2, the same catalyst as in example 2 was tested in the same experimental set-up with a catalyst bed of 30 cm. The gas mixtures (numbers in volume percent) shown in table 2C were adjusted.

TABLE 2C

	Gas mixture 1	Gas mixture 2	Gas mixture 3
				Hydrogen gas	8.36	7.82	12.41
Ethylene	37.30	35.13	35.31
				Acetylene	0.016	0.007	0.015
Ethane (III)	48.90	53.37	45.43
				Oxygen gas	0.44	0.502	0.732
Nitrogen gas	2.05	1.95	3.32
				Carbon monoxide	2.92	1.22	2.77

In comparative example 2, a pressure of 24 bar was used. The results for the three gas mixtures given in table 2C are shown in table 2D. As can be seen from Table 2D, the ethylene loss rate is very high under the specified conditions, especially at high hydrogen/oxygen ratios.

TABLE 2D

	Mixture 1	Mixture 2	Mixture 3
				GHSV h-1	1927	2449	1961
Inlet temperature C	185.5	155	158.5
				Ethylene loss%	3.2	4.2	5.5
Oxygen conversion%	100	100	100
				Conversion of acetylene%	98.7	99.1	99.6