BR112019001830B1 - PROCESS FOR PRODUCING ETHYLENE FROM ETHANE, AND CHEMICAL COMPLEX - Google Patents

Abstract

The present invention relates to a process for producing ethylene from ethane comprising: subjecting a stream comprising ethane to steam cracking conditions in a steam cracking unit forming part of a steam cracker configuration, resulting in a stream comprising unconverted ethane, ethylene and hydrogen; feeding a separation unit with a stream comprising unconverted ethane, ethylene and hydrogen forming part of the steam cracker configuration, and separating said stream in said separation unit into a stream comprising hydrogen and a stream comprising unconverted ethane. converted and ethylene; feeding a C2 separation unit with a stream comprising unconverted ethane and ethylene forming part of the steam cracker configuration, and separating said stream in the C2 separation unit into a stream comprising ethylene and a stream comprising ethane unconverted; optionally, recycling unconverted ethane from the stream comprising unconverted ethane from the C2 separation unit to the steam cracking unit; subjecting a stream comprising ethane to oxidative dehydrogenation conditions (...).

Description

FIELD OF INVENTION

[001] The present invention relates to a process for producing ethylene from ethane and to a chemical complex that is suitable for carrying out such an ethylene production process.

BACKGROUND OF THE INVENTION

[002] It is known to produce ethylene from ethane by steam cracking an ethane stream under the influence of heat into a product stream comprising ethylene and hydrogen. Before any subsequent step, in which ethylene is further converted into useful chemical intermediates, the ethylene containing product stream must be purified. In addition to ethylene and hydrogen, a steam cracker product stream may also contain acetylene and unconverted ethane. Furthermore, said product stream may contain some carbon monoxide and carbon dioxide as impurities. Carbon dioxide can be produced in the presence of oxygen (resulting from some small air ingress into the steam cracking unit) and/or in hydrocarbon water alteration reactions. Additionally, carbon monoxide and carbon dioxide may be present as contaminants in food. Still further, said product stream may contain methane and C3+ hydrocarbons whose impurities may be formed during ethane vapor cracking which is generally a non-selective non-catalytic conversion process. The latter impurities can also originate from the ethane feed stream. Components other than ethylene need to be removed from the product stream as they interfere with any subsequent steps in which ethylene is further converted.

[003] In general, carbon dioxide is removed from the steam cracker product stream by passing the stream through a carbon dioxide removal unit, which may come into contact with an aqueous solution of a base, for example sodium hydroxide (caustic solution wash). Hydrogen and methane can be separated from the other components by cryogenic distillation. Alternatively, the hydrogen and methane can be separated along with the C2 hydrocarbons, which comprise ethylene, any unconverted ethane and any acetylene, from any C3+ hydrocarbons in the product stream. Next, the C2 hydrocarbons need to be separated from the resulting stream comprising hydrogen, methane and C2 hydrocarbons. Acetylene can be removed by hydrogenating it in ethylene. Finally, the ethane has to be separated from the ethylene, which can also be done by distillation. Having to remove all of these components from the ethylene containing product stream of the steam cracker is very inconvenient and results in a relatively high expense to produce ethylene. For example, the separation of ethane from ethylene through cryogenic distillation in so-called “C2 separator” columns is known. In such cryogenic distillation, a relatively high pressure and a relatively low (cryogenic) temperature are applied to effect the separation of ethane from ethylene.

[004] The downstream section of an ethane vapor cracker configuration, wherein the downstream section may comprise multiple units to perform the above-described functions of removing carbon dioxide, separating components (e.g., by distillation ) and acetylene hydrogenation, has a certain capacity that is determined by that unit which is lowest capacity. Generally speaking, there may be a situation where the capacity of a steam cracking unit upstream of the downstream section in the steam cracker configuration is not compatible with the larger capacity of the downstream section. In such a case, the capacity of the downstream section is not fully utilized which leads to a technically disadvantageous inefficient and more expensive process for producing ethylene from ethane.

[005] The situation mentioned above where the capacity of a steam cracking unit (comprising one or more furnaces) upstream of the downstream section in an ethane steam cracker configuration is not compatible with the larger capacity of the section downstream can generally occur when there is a bottleneck in an existing steam cracker configuration or when it is desired to expand the total capacity of a steam cracker configuration. This may involve a case where a steam cracker oven is near or has reached the end of its useful life. Additionally, this may involve a case where there is a desire to utilize potential reserve capacity in the back-end separation section of an existing steam cracker configuration due to additional design headroom (excessive design of the distillation towers or installation of higher capacity internal components) and/or lower than designed steam cracking furnace (or furnaces) performance. The latter may also be a result of revamping an existing liquid vapor cracker configuration over a gas (ethane) vapor cracker configuration. Still further, this may apply to situations where 1 or more of several steam crackers has/have to be taken out of service (e.g. for maintenance or for any other reason).

[006] An object of the present invention is to provide a process for producing ethylene from ethane, which process can be an efficient and inexpensive technically advantageous process, involves steam cracking of ethane into ethylene and hydrogen in a unit steam cracking unit that is part of a steam cracker configuration, more particularly, in a situation where the capacity of the steam cracking unit upstream of the downstream section in the steam cracker configuration is not compatible with the larger capacity of the downstream section. Such technically advantageous processes may preferably result in lower energy demand and/or lower capital expenditure.

SUMMARY OF THE INVENTION

[007] Surprisingly, it was found that the object mentioned above can be obtained by feeding an effluent from an oxidative dehydrogenation (ODH) configuration to the configuration of steam crackers, in which the ethane of the ODH configuration is dehydrogenated by oxidation in ethylene and water, and wherein the effluent departing from the ODH configuration with which the steam cracker configuration is fed comprises unconverted ethane and ethylene.

[008] Consequently, the present invention relates to a process for producing ethylene from ethane which comprises: subjecting a stream comprising ethane to steam cracking conditions in a steam cracking unit which is part of a configuration from steam crackers, resulting in a stream comprising ethane, ethylene and unconverted hydrogen; feeding a stream comprising unconverted ethane, ethylene and hydrogen to a separation unit which is part of the steam cracker configuration and separating said stream in said separation unit into a stream comprising hydrogen and a stream comprising ethane and ethylene unconverted; feeding a C2 separation unit with a stream comprising unconverted ethane and ethylene forming part of the steam cracker configuration and separating said stream in the C2 separation unit into a stream comprising ethylene and a stream comprising unconverted ethane. converted; optionally, recycling unconverted ethane from the stream comprising unconverted ethane from the C2 separation unit to the steam cracking unit; subjecting a stream comprising ethane to oxidative dehydrogenation (ODH) conditions in an ODH unit that is part of an ODH configuration, which results in a stream comprising unconverted ethane, ethylene and water; feeding a water condensing unit with a stream comprising unconverted ethane, ethylene and water forming part of the ODH configuration and removing water from said stream by means of condensation in the water condensing unit, resulting in a stream comprising unconverted ethane and ethylene; feeding the steam cracker configuration with an effluent from the ODH configuration, which effluent comprises unconverted ethane and ethylene; optionally recycling unconverted ethane from the stream comprising unconverted ethane departing from the C2 separation unit to the ODH unit; Furthermore, the present invention relates to a chemical complex comprising a steam cracker configuration and an oxidative dehydrogenation (ODH) configuration, wherein: the steam cracker configuration comprises a steam cracking unit, a carbon dioxide removal, an optional drying unit, a 1st separation unit, a 2nd separation unit, an optional acetylene hydrogenation unit and a C2 separation unit, each unit comprising one or more feed lines and one or more effluent lines; The ODH configuration comprises an ODH unit, a water condensing unit, an optional carbon dioxide removal unit and an optional drying unit, each unit comprising one or more supply lines and one or more supply lines. effluent; the ODH configuration is integrated into the steam crackers configuration in a position upstream of the optional acetylene hydrogenation unit and upstream of the C2 separation unit; and no ODH unit feed line is integrated with a feed line or effluent line of a steam cracker configuration unit, with the exception that a steam cracking unit feed line and a steam cracker feed line of the ODH unit can be integrated and/or that an optional recycling effluent line from the C2 separation unit and an ODH unit feed line can be integrated.

BRIEF DESCRIPTION OF THE DRAWINGS

[009] Figure 1 depicts an embodiment of the present invention in which the steam cracker configuration is fed with an effluent from a water condensing unit of the oxidative dehydrogenation (ODH) configuration, said effluent comprising ethane and ethylene not converted.

[0010] Figure 2 depicts an embodiment of the present invention in which the steam cracker configuration is fed with an effluent from a carbon dioxide removal unit of the ODH configuration, said effluent comprising unconverted ethane and ethylene.

[0011] Figure 3 depicts an embodiment of the present invention in which the steam cracker configuration is fed with an effluent from a drying unit of the ODH configuration, said effluent comprising unconverted ethane and ethylene.

DETAILED DESCRIPTION OF THE INVENTION

[0012] In the integrated process of the present invention, both a steam cracker configuration and an oxidative dehydrogenation (ODH) configuration are used.

[0013] The steam cracker configuration mentioned above comprises: (a) a steam cracking unit in which a stream comprising ethane is subjected to steam cracking conditions, which results in a stream comprising ethane, ethylene and unconverted hydrogen; (b) a separation unit in which a stream comprising ethane, ethylene and unconverted hydrogen is separated into a stream comprising hydrogen and a stream comprising unconverted ethane and ethylene; (c) a C2 separation unit in which a stream comprising unconverted ethane and ethylene is separated into a stream comprising ethylene and a stream comprising unconverted ethane.

[0014] Furthermore, in the present invention, the steam cracker configuration may comprise a carbon dioxide removal unit, a drying unit, one or more separation units other than the C2 separation unit mentioned above, a acetylene hydrogenation system and/or one or more compressors.

[0015] The oxidative dehydrogenation (ODH) configuration mentioned above comprises: (i) an ODH unit in which a stream comprising ethane is subjected to ODH conditions, which results in a stream comprising ethane, ethylene and non-water. converted; (ii) a water condensing unit, wherein water is removed from a stream comprising unconverted ethane, ethylene and water by condensation, which results in a stream comprising unconverted ethane and ethylene.

[0016] Furthermore, in the present invention, the ODH configuration may comprise a carbon dioxide removal unit and a drying unit.

[0017] In the present invention, the integration between the steam cracker configuration and the ODH configuration mentioned above is carried out by feeding the steam cracker configuration with an effluent that starts from the ODH configuration, with the effluent comprising ethane and unconverted ethylene. Suitably, in the present invention, the steam cracker configuration in a position that is downstream of the steam cracking unit is fed with an effluent departing from the ODH configuration, the effluent comprising unconverted ethane and ethylene.

[0018] Document No. WO2014134703 discloses incorporating an ethane ODH process into the development process, as carried out in the downstream section of an ethane vapor cracker configuration, wherein the ODH unit becomes part of the cracker configuration steam and ethane containing feed stream to the ODH unit originates only from the steam cracker configuration.

[0019] In Figure 4 of document No. WO2014134703, a C2 separator for separating ethylene from ethane, the separator being part of a steam cracker configuration, is connected to an ODH unit at the bottom of the C2 separator. That is, in the process of said Figure 4, ethane from the bottom of the C2 separator is sent to the ODH unit that is downstream of the C2 separator. In the process of Figure 6 of document No. WO2014134703, ethane and ethylene from the C2 separator medium are sent to an ODH unit that is downstream of the C2 separator. In the process of Figure 8 of document No. WO2014134703, ethane and ethylene from hydrogenation units, which are part of a steam cracker configuration, are sent to an ODH unit that is downstream of the hydrogenation unit. In all these processes of Figures 4, 6 and 8 of document No. WO2014134703, no effluent from the ODH unit is sent to the steam cracker configuration in any position.

[0020] Furthermore, in Figure 7 of document No. WO2014134703, ethane and ethylene from a steam cracker are sent to an ODH unit, with the output stream thereof being sent to a C2 separator to separate ethylene of ethane, and the separator is part of the configuration of steam crackers. That is, in the process of said Figure 7, ethane and ethylene from the steam cracker are sent to the ODH unit which is upstream of the C2 separator. In the process of Figure 7 of WO2014134703, the ODH unit is part of the steam crackers configuration. There is no separate ODH configuration. For the input stream to the ODH unit, it originates from a steam cracker and the output stream from the ODH unit is sent to a C2 separator, including both the steam cracker and the C2 separator. are part of the steam cracker configuration.

[0021] In all the processes mentioned above in Figures 4, 6, 7 and 8 of document No. WO2014134703, the ODH unit, as incorporated in a steam cracker configuration, cannot be instrumental in enabling the full use of all the capacity of the downstream section of a configuration of steam crackers, in a situation where the capacity of a steam cracking unit upstream of said downstream section is not compatible with the higher capacity of the downstream section. For the currents with which the ODH units are fed, in said Figures 4, 6, 7 and 8, they originate, either directly or indirectly, from the effluent of the steam cracking unit. As stated in document No. WO2014134703 (see page 46), the invention of document No. WO2014134703 resides in ethane in conversion (not yet conversion) of the cracker product stream into ethylene in a cooperative ODH unit, with the aim to reduce the ethane load in the separation train. This is different from the present invention, in which the downstream section of a steam cracker configuration can be fed with a larger quantity of effluent, i.e., both the effluent originating from the steam cracking unit and the effluent that originates from the ODH unit, can be fed, as compared to other cases in which the amount of effluent with which such a downstream section of a steam cracker configuration can be fed can be determined solely by the effluent originating from the cracking unit steam. Examples of such other cases are (i) cases in which no ODH units are used at all; or (ii) the cases described above, as illustrated by the processes of Figures 4, 6, 7 and 8 of document No. WO2014134703, in which an ethane ODH process is incorporated into the development process as carried out in the downstream section of a ethane steam cracker configuration, wherein the ODH unit becomes part of the steam cracker configuration and the ethane containing feed stream to the ODH unit originates only from the steam cracker configuration.

[0022] Therefore, the present invention provides a process for producing ethylene from ethane, involving steam cracking of ethane into ethylene and hydrogen, and this process may be more technically advantageous, more efficient and less expensive compared to other cases as described above. Such technically advantageous processes may preferably result in lower energy demand and/or lower capital expenditure.

[0023] In particular, by integrating an ODH configuration with a steam cracker configuration by feeding an effluent that starts from the ODH configuration, with the effluent comprising unconverted ethane and ethylene, the steam cracker configuration , in particular the section downstream of the steam cracker configuration feeding said effluent to the steam cracker configuration in a position that is downstream of the steam cracking unit, the present invention is useful for eliminating the bottleneck of a steam cracker configuration exists or expand the total capacity of a steam cracker configuration. Advantageously, in this way, a relatively high capacity of the downstream section of an ethane steam cracker configuration compared to the capacity of a steam cracker unit (comprising one or more furnaces) upstream of that downstream section , can be used completely. The foregoing may involve a case where a steam cracker furnace is near or has reached the end of its useful life. Furthermore, this may involve a case where there is a desire to utilize potential spare capacity in the backend separation section of an existing steam cracker configuration due to additional design headroom (overdesign of distillation towers or installation of higher capacity internal components) and/or the performance of the steam cracking furnace (or steam cracking furnaces) lower than designed. The latter may also be a result of upgrading an existing liquid steam crackers configuration over a gas (ethane) steam crackers configuration. Also, this may apply to situations where 1 or more of several steam crackers has/have to be taken out of service (eg for maintenance or for any other reason). The foregoing examples show that the integration of the present invention can be advantageously applied in many practical situations, which leads to a technically advantageous, inexpensive and efficient integrated process for the production of ethylene from ethane, which involves both steam cracking of ethane into ethylene and hydrogen and oxidative dehydrogenation of ethane into ethylene and water.

[0024] In addition to enabling full utilization of the relatively high capacity of the downstream section of an ethane vapor cracker configuration as described above, the present invention also has the following additional advantages. An ethane ODH configuration comprising an ODH unit (e.g. 1 ODH reactor) and a water condensing unit involves a smaller footprint (less physical area required), low capital intensity, low capital energy and , consequently, an overall low intensity of CO2 emissions. In an ethane ODH process, less energy is required in compressors and distillation towers due to the fact that the ODH exhaust gas has higher molecular weight (ODH effluent substantially has no light components such as hydrogen and methane produced, compared to, for example, vapor cracking of ethane), the ODH process can be operated at a high pressure (e.g., 0.2 to 1.0 MPa (2 to 10 bar)) and Finally, it is an exothermic chemical process that produces a high liquid pressure current, and steam can also be used advantageously in the chemical complex of the present invention. In the case of the latter, the current produced in the ODH process can be used advantageously in the configuration of steam crackers of the chemical complex. And vice versa: any current produced in the steam cracking process can be used advantageously in the ODH configuration of the chemical complex. Furthermore, generally speaking, an ODH process produces a much more concentrated product slate distribution (i.e., no or fewer byproducts such as methane and C3+ hydrocarbons as produced in ethane vapor cracking), but the effluents of ODH are still chemically compatible with ethane vapor cracker effluents, which makes the alignment and separation requirement much simpler, less expensive and less energy intensive.

[0025] These and more advantages of the present invention will also be evident from the detailed description.

[0026] Within the present specification, the following terms have the following meanings.

[0027] “C3+ hydrocarbons” comprise hydrocarbons that have a number of carbons equal to 3 or greater. The C3+ hydrocarbons may comprise propane and/or propylene.

[0028] “C2+ hydrocarbons” comprise hydrocarbons that have a number of carbons equal to 2 or greater. C2+ hydrocarbons may comprise ethane, ethylene, acetylene, propane and/or propylene.

[0029] “C2 hydrocarbons” comprise hydrocarbons that have a carbon number of 2. C2 hydrocarbons may comprise ethane, ethylene and/or acetylene.

[0030] In the case of the process of the present invention, “steam cracking unit” means a unit in which ethane is converted, subjecting it to steam cracking conditions, into ethylene and hydrogen. In treating the complex of the present invention, “steam cracking unit” means a unit that is suitable for converting ethane, subjecting it to steam cracking conditions, into ethylene and hydrogen. The steam cracking unit may comprise an oven.

[0031] When it comes to the process of the present invention, “oxidative dehydrogenation unit” means a unit in which ethane is converted, subjecting it to oxidative dehydrogenation conditions (ODH), into ethylene and water. In the case of the complex of the present invention, the “oxidative dehydrogenation unit” means a unit that is suitable for converting, subjecting it to ODH conditions, into ethylene and water. The ODH unit may comprise a reactor which may be a catalytic reactor which is a reactor containing a catalyst.

[0032] In the case of the process of the present invention, “carbon dioxide removal unit” means a unit in which carbon dioxide is removed from a stream comprising ethylene, hydrogen and carbon dioxide. In dealing with the complex of the present invention, "carbon dioxide removal unit" means a unit that is suitable for removing carbon dioxide from a stream comprising ethylene, hydrogen and carbon dioxide. The carbon dioxide removal agent with which the carbon dioxide removal unit was fed may be an aqueous solution of a base, for example sodium hydroxide or an amine.

[0033] When dealing with the process of the present invention, “drying unit” means a unit in which water is removed from a stream comprising ethylene, hydrogen and water. In dealing with the complex of the present invention, "drying unit" means a unit that is suitable for removing water from a stream comprising ethylene, hydrogen and water.

[0034] In the case of the process of the present invention, the “acetylene hydrogenation unit” means a unit in which acetylene, subjecting it to hydrogen conditions, is converted into ethylene. In the case of the complex of the present invention, “acetylene hydrogenation unit” means a unit that is suitable for converting acetylene, subjecting it to hydrogen conditions, into ethylene. The acetylene hydrogenation unit may comprise a reactor which may be a catalytic reactor which is a reactor containing a catalyst.

[0035] When it comes to the process of the present invention, “C2 separation unit” means a unit in which ethylene is separated from ethane. In dealing with the complex of the present invention, “C2 separation unit” means a unit that is suitable for separating ethylene from ethane. Ethylene can be separated from ethane in any way, for example, through distillation, absorption or adsorption.

[0036] Furthermore, although the process and chemical complex and configurations of the present invention and the stream or streams used in said process are described in terms of “comprising”, “containing” or “including”, one or several steps or units or components, they may also “consist essentially” or “consist” of said one or more various steps or units or components described.

[0037] In the context of the present invention, in a case where a chain comprises two or more components, these components must be selected in a general amount that does not exceed 100% by volume or 100% by volume.

[0038] The present process is a process for producing ethylene from ethane which comprises: subjecting a stream comprising ethane to steam cracking conditions in a steam cracking unit which is part of a steam cracker configuration, resulting in a stream comprising ethane, ethylene and unconverted hydrogen; feeding a stream comprising unconverted ethane, ethylene and hydrogen to a separation unit which is part of the steam cracker configuration and separating said stream in said separation unit into a stream comprising hydrogen and a stream comprising ethane and ethylene unconverted; feeding a stream comprising ethane and unconverted ethylene forming part of the steam crackers configuration to a C2 separation unit and separating said stream in the C2 separation unit into a stream comprising ethylene and a stream comprising unconverted ethane converted; optionally, recycling unconverted ethane from the stream comprising unconverted ethane from the C2 separation unit to the steam cracking unit; subjecting a stream comprising ethane to oxidative dehydrogenation (ODH) conditions in an ODH unit that is part of an ODH configuration, which results in a stream comprising unconverted ethane, ethylene and water; feeding a water condensing unit with a stream comprising unconverted ethane, ethylene and water forming part of the ODH configuration and removing water from said stream by means of condensation in the water condensing unit, resulting in a stream comprising unconverted ethane and ethylene; feeding the steam cracker configuration with an effluent from the ODH configuration, which effluent comprises unconverted ethane and ethylene; optionally recycle unconverted ethane from the stream comprising unconverted ethane departing from the C2 separation unit to the ODH unit.

[0039] As described above, in the present invention, the integration between the steam cracker configuration and the ODH configuration is carried out by feeding an effluent that starts from the ODH configuration, with the effluent comprising unconverted ethane and ethylene, the configuration of steam crackers, suitably in a position that is downstream of the steam cracker unit. Furthermore, suitably, the ODH unit of the ODH configuration is not fed with any unconverted ethane from an effluent departing from the steam cracker configuration, with the exception that an optional recycling of unconverted ethane from an effluent departing from the steam cracker configuration part of the C2 separation unit of the steam crackers configuration to the ODH unit of the ODH configuration. Still further, suitably, the ODH unit is fed with ethane that originates from one or more sources selected from the group consisting of a) the fresh ethane source that is used to feed ethane to the steam cracking unit; b) another source of fresh ethane, different from said first source mentioned under a); and c) unconverted ethane from an effluent departing from the C2 separation unit. Within this specification, “fresh ethane” means ethane that does not include unconverted ethane. Within the present specification, “unconverted ethane” means methane that has been subjected to either steam cracking conditions or oxidative dehydrogenation conditions in the process of the present invention, but which has not been converted. In relation to said sources of fresh ethane mentioned in a) and b) above, the fresh ethane to be subjected to steam cracking conditions and/or oxidative dehydrogenation conditions in the process of the present invention can be supplied by a plant that produces a ethane-containing stream, either as a main stream or as a side stream, such as a natural gas production plant, shale gas production plant, natural gas processing plant, fractionation and recovery plant. Natural Gas, Liquid Natural Gas (LNG) production plant and so on, and the plants can also be generally referred to as “midstream” plants. Therefore, the present process can be integrated with any of such intermediate current plants. However, in the present invention, the source of fresh ethane is not essential.

[0040] Generally speaking, in the present invention, the feed to the ODH unit may comprise: 1) unconverted ethane and no fresh ethane; or 2) unconverted ethane and fresh ethane; or 3) fresh ethane and unconverted ethane. Also, generally, in the present invention, the feed to the steam cracker unit may comprise: 1) unconverted ethane and no fresh ethane; or 2) unconverted ethane and fresh ethane; or 3) fresh ethane and unconverted ethane. In particular, the ODH unit can be fed with fresh ethane. Furthermore, in particular, the steam cracking unit can be fed with fresh ethane. Still further, in particular, both the ODH unit and the steam cracking unit can be fed with fresh ethane. As described above, fresh feed ethane involves feeding ethane that has not been subjected to steam cracking conditions nor oxidative dehydrogenation (ODH) conditions. The fresh ethane that the ODH unit was fed with and the fresh ethane that the steam cracking unit was fed with may originate from the same or different sources.

[0041] In the present process, the effluent departing from the ODH configuration, where the effluent comprises unconverted ethane and ethylene and the steam cracker configuration is fed with the effluent, may be the stream comprising unconverted ethane and ethylene which starts from the water condensing unit of the ODH configuration. Preferably, the C2 separation unit of the steam cracker configuration is fed with the unconverted ethane and ethylene from the stream comprising unconverted ethane and ethylene departing from the water condensing unit of the ODH configuration.

[0042] In the present process, the stream departing from the steam cracking unit of the steam cracker configuration may comprise ethane, ethylene, hydrogen, methane, carbon monoxide, carbon dioxide and unconverted C3+ hydrocarbons; and the stream departing from the ODH unit of the ODH configuration may comprise unconverted ethane, ethylene, water, carbon monoxide and carbon dioxide. In such a case, the ethylene production process of the present invention may comprise the following steps: subjecting a stream comprising ethane to steam cracking conditions in a steam cracking unit that is part of a steam cracker configuration, resulting in in a stream comprising ethane, ethylene, hydrogen, methane, carbon monoxide, carbon dioxide and unconverted C3+ hydrocarbon; feeding a stream comprising ethane, ethylene, hydrogen, methane, carbon monoxide, carbon dioxide and unconverted C3+ hydrocarbons to a carbon dioxide removal unit which is part of the steam cracker configuration and removing carbon dioxide from said current in said carbon dioxide removal unit, which results in a stream comprising ethane, ethylene, hydrogen, methane, carbon monoxide and unconverted C3+ hydrocarbons; feeding a separation unit with a stream comprising ethane, ethylene, hydrogen, methane, carbon monoxide and unconverted C3+ hydrocarbons forming part of the steam cracker configuration and separating said stream in said separation unit into a stream comprising hydrogen, methane and carbon monoxide and a stream comprising C3+ hydrocarbons; feeding a C2 separation unit with unconverted ethane and ethylene from a stream comprising ethane, ethylene, hydrogen, methane, carbon monoxide and unconverted C3+ hydrocarbons that is part of the steam cracker configuration and separating said stream in the unit separating C2 into a stream comprising ethylene and a stream comprising unconverted ethane; optionally, recycling unconverted ethane from the stream comprising unconverted ethane from the C2 separation unit to the steam cracking unit; subjecting a stream comprising ethane to oxidative dehydrogenation (ODH) conditions in an ODH unit that is part of an ODH configuration, resulting in a stream comprising unconverted ethane, ethylene, water, carbon monoxide and carbon dioxide; feeding a water condensing unit with a stream comprising unconverted ethane, ethylene, water, carbon monoxide and carbon dioxide forming part of the ODH configuration and removing water from said stream by means of condensation in the ODH condensing unit water, resulting in a stream comprising unconverted ethane, ethylene, carbon monoxide and carbon dioxide; feeding the steam cracker configuration with an effluent from the ODH configuration, which effluent comprises unconverted ethane and ethylene; optionally recycling unconverted ethane from the stream comprising unconverted ethane departing from the C2 separation unit to the ODH unit; Furthermore, the stream departing from the ODH unit of the ODH configuration may also comprise unconverted oxygen (used as an oxidizing agent in the ODH process). Preferably, such unconverted oxygen is removed before the steam cracker configuration is fed with an effluent from the ODH configuration, the effluent comprising unconverted ethane and ethylene, in view of safety considerations and the presence of hydrogen in steam cracker effluents.

[0043] In the carbon dioxide removal step of the process described above, the carbon dioxide removal unit of the steam cracker configuration is fed with a stream comprising ethane, ethylene, hydrogen, methane, carbon monoxide, carbon dioxide, carbon and unconverted C3+ hydrocarbons. The last stream may be the stream leaving the steam cracking unit. Optionally, if the stream comprising ethane, ethylene, hydrogen, methane, carbon monoxide and unconverted C3+ hydrocarbons resulting from the carbon dioxide removal step comprises water, a drying unit is fed with the stream as part of steam crackers setup to remove water.

[0044] Furthermore, in the process described above, a separation unit of the steam cracker configuration is fed with a stream comprising ethane, ethylene, hydrogen, methane, carbon monoxide and unconverted C3+ hydrocarbons. The last stream may be the stream departing from the carbon dioxide removal unit or optional drying unit mentioned above. In the last separation unit, the last stream is separated into a stream comprising hydrogen, methane and carbon monoxide and a stream comprising C3+ hydrocarbons. In a 1st embodiment, said stream comprising ethane, ethylene, hydrogen, methane, carbon monoxide and unconverted C3+ hydrocarbons is separated into a stream comprising hydrogen, methane and carbon monoxide and into a stream comprising C2+ hydrocarbons, being that C2+ hydrocarbons comprise ethane, ethylene and unconverted C3+ hydrocarbons. In a 2nd embodiment, said stream comprising ethane, ethylene, hydrogen, methane, carbon monoxide and unconverted C3+ hydrocarbons is separated into a stream comprising hydrogen, methane, carbon monoxide and C2 hydrocarbons, with C2 hydrocarbons comprising ethane and unconverted ethylene and a stream comprising C3+ hydrocarbons. In said 1st embodiment, the separated stream comprising C2+ hydrocarbons can be fed to an additional separation unit, said stream being separated into a stream comprising C2 hydrocarbons and a stream comprising C3+ hydrocarbons. In said 2nd embodiment, an additional separation unit may be fed with the separated stream comprising hydrogen, methane, carbon monoxide and C2 hydrocarbons, said stream being separated into a stream comprising hydrogen, methane and carbon monoxide and a stream comprising C2 hydrocarbons. In both said embodiments, the aforementioned C2 separation unit of the steam cracker configuration can be fed with the separated stream comprising C2 hydrocarbons departing from said additional separation unit, the latter stream being separated into a stream comprising ethylene and a stream comprising unconverted ethane.

[0045] Still further, in the process described above, a carbon dioxide removal unit that is part of the ODH configuration can be fed with the stream comprising ethane, ethylene, carbon monoxide and unconverted carbon dioxide departing from the water condensing unit of the ODH configuration, wherein carbon dioxide is removed from said stream, which results in a stream comprising unconverted ethane, ethylene and carbon monoxide. Optionally, if the stream comprising unconverted ethane, ethylene and carbon monoxide resulting from the carbon dioxide removal step comprises water, a drying unit as part of the ODH configuration can be fed with the stream in order to to remove the water.

[0046] Still further, in the process described above, the steam cracker configuration can be fed with an effluent that starts from the ODH configuration, with the effluent comprising unconverted ethane and ethylene. Suitably, said effluent departing from the ODH configuration is an effluent originating, either directly or indirectly, from the ODH unit.

[0047] In the process described above, the effluent mentioned above that starts from the ODH configuration, where the effluent comprises unconverted ethane and ethylene, and the steam crackers configuration is fed with the effluent, may be the stream comprising unconverted ethane, ethylene, carbon monoxide and carbon dioxide leaving the water condensing unit of the ODH configuration. Preferably, the carbon dioxide removal unit of the steam cracker configuration is fed with the last stream comprising ethane, ethylene, carbon monoxide and unconverted carbon dioxide departing from the water condensing unit of the ODH configuration. . This is illustrated in Figure 1 (at line 35).

[0048] In addition, in the process described above, the above-mentioned effluent that starts from the ODH configuration, the effluent comprising unconverted ethane and ethylene, and the steam crackers configuration is fed with the effluent, can be the current which comprises unconverted ethane, ethylene and carbon monoxide which comes from the optional carbon dioxide removal unit of the ODH configuration. Preferably, the steam cracker configuration separation unit is fed with the last stream comprising unconverted ethane, ethylene and carbon monoxide from the ODH configuration optional carbon dioxide removal unit, the stream being comprising ethane, ethylene, hydrogen, methane, carbon monoxide and unconverted C3+ hydrocarbons is separated into a stream comprising hydrogen, methane and carbon monoxide and a stream comprising C3+ hydrocarbons. In a case where the streams resulting from the carbon dioxide removal steps comprise water as described above, the above-mentioned drying unit of the steam cracker configuration may be fed with the stream departing from the carbon dioxide removal unit. carbon of the ODH configuration. This is illustrated in Figure 2 (on line 40). Furthermore, in a case where the streams resulting from the carbon dioxide removal steps comprise water and the ODH configuration comprises the drying unit as described above, that separation unit of the steam cracker configuration may be fed with the stream departing from the drying unit of the ODH configuration and comprising unconverted ethane, ethylene and carbon monoxide, in this separation unit a stream comprising unconverted ethane, ethylene, hydrogen, methane, carbon monoxide and C3+ hydrocarbons is separated into a stream comprising hydrogen, methane and carbon monoxide and the stream comprising C2+ hydrocarbons (“1st modality” described above). This is illustrated in Figure 3 (on line 45). Furthermore, in a case where the streams resulting from the carbon dioxide removal steps comprise water and the ODH configuration comprises the drying unit as described above, that separation unit of the steam cracker configuration may be fed with the stream departing from the drying unit of the ODH configuration and comprising unconverted ethane, ethylene and carbon monoxide, in this separation unit a stream comprising hydrogen, methane, carbon monoxide and C2+ hydrocarbons is separated into a stream comprising hydrogen, methane and carbon monoxide and the stream comprising C2+ hydrocarbons (“2nd modality” described above). This is also illustrated in Figure 3 (on line 46).

[0049] In the present process, the stream departing from the steam cracking unit of the steam cracker configuration may additionally comprise acetylene; and the stream departing from the ODH unit of an ODH configuration may further comprise acetylene. In such a case, the ethylene production process of the present invention may comprise an acetylene hydrogenation step, wherein in an acetylene hydrogenation unit a stream comprising unconverted ethane, ethylene and acetylene is subjected to hydrogen conditions, of in order to convert acetylene to ethylene. Preferably, the acetylene hydrogenation unit is part of the steam cracker configuration. In the latter case, the acetylene hydrogenation unit of the steam cracker configuration may be fed a stream comprising unconverted ethane, ethylene and acetylene, which results in a stream comprising unconverted ethane and ethylene, the unit of C2 separation mentioned above can be fed with the last current. In such a case, the acetylene hydrogenation unit of the steam crackers configuration can be fed with a stream containing hydrogen. Hydrogen is a hydrogenating agent which can hydrogenate acetylene to ethylene and which can be derived from the configuration of steam crackers.

[0050] More particularly, in the present process in a case in which acetylene is present, as described above, in the 1st embodiment mentioned above, a stream comprising unconverted ethane, ethylene, acetylene, hydrogen, methane, carbon monoxide and C3+ hydrocarbons is separated into a stream comprising hydrogen, methane and carbon monoxide and a stream comprising C2+ hydrocarbons, with the C2+ hydrocarbons comprising unconverted ethane, ethylene, acetylene and C3+ hydrocarbons. Furthermore, in the 2nd embodiment mentioned above, a stream comprising unconverted ethane, ethylene, acetylene, hydrogen, methane, carbon monoxide and C3+ hydrocarbons is separated into a stream comprising hydrogen, methane, carbon monoxide and C2 hydrocarbons, being that the C2 hydrocarbons comprise unconverted ethane, ethylene and acetylene and a stream comprising C3+ hydrocarbons. In said 1st embodiment, the separated stream comprising C2+ hydrocarbons can be fed to an additional separation unit, said stream being separated into a stream comprising C2 hydrocarbons and a stream comprising C3+ hydrocarbons. In said 2nd embodiment, an additional separation unit may be fed with the separated stream comprising hydrogen, methane, carbon monoxide and C2 hydrocarbons, said stream being separated into a stream comprising hydrogen, methane and carbon monoxide and a stream comprising C2 hydrocarbons. In both embodiments, an acetylene hydrogenation unit may be fed with the separated stream comprising C2 hydrocarbons departing from said additional separation unit as part of the steam cracker configuration, with the acetylene being converted to ethylene, which results in a stream comprising unconverted ethane and ethylene, and then the C2 separation unit mentioned above in the steam cracker configuration can be fed with the latter stream, with the latter stream being separated into a stream comprising ethylene and a stream comprising unconverted ethane.

[0051] In the process of the present invention, a stream comprising ethane is subjected to steam cracking conditions in a steam cracking unit that is part of a steam cracker configuration, resulting in a stream comprising ethane, ethylene and unconverted hydrogen. Suitable steam cracking conditions for this steam cracking step are described below.

[0052] Suitably, in the steam cracking step mentioned above, the steam cracking unit is not fed with any oxygen-containing stream since there is no need to use oxygen as an oxidizing agent. However, carbon dioxide can still be produced as an impurity in the presence of oxygen (resulting from some air ingress into the steam cracking unit) and/or in hydrocarbon water alteration reactions. Additionally, carbon monoxide and carbon dioxide can enter the steam cracking process as feed contaminants.

[0053] Furthermore, suitably, in the steam cracking step mentioned above, no catalyst is used. Preferably, said steam cracking step is carried out at an elevated temperature, more preferably in the range of 650 to 1,000 °C, most preferably of 750 to 950 °C. Hydrocarbon steam cracking processes are well known. Reference is made, for example, to Kniel et al., Ethylene, Keystone to the Petrochemical Industry, Marcel Dekker, Inc., New York, 1980, in particular, chapters 6 and 7.

[0054] In the process of the present invention, a stream comprising ethane is subjected to oxidative dehydrogenation (ODH) conditions in an ODH unit that is part of an ODH configuration, which results in a stream comprising ethane, ethylene and unconverted water. ODH conditions suitable for this ODH step are described below.

[0055] In the ODH step mentioned above, subjecting a stream comprising ethane to ODH conditions may comprise placing the stream comprising ethane in contact with oxygen (O2). Said oxygen is the oxidizing agent in the ODH reaction. In the ODH step, the ODH unit can be fed with oxygen (O2) and a stream comprising ethane. The ODH unit may comprise a reactor, the reactor may contain an ODH catalyst, in particular, a mixed metal oxide catalyst containing molybdenum, vanadium, niobium and optionally tellerium. The oxygen then comes into contact with said catalyst in the ODH reactor, resulting in the oxidative dehydrogenation of ethane.

[0056] In the ODH step of the process of the present invention, the reactor can be fed with oxygen and ethane together or separately. That is, the reactor may be fed with one or more feed streams, suitably gas streams, comprising one or more of said 2 components. For example, the reactor can be fed with a stream comprising oxygen and ethane. Alternatively, the reactor may be fed with two or more suitably corresponding feed streams of gas, the feed streams may form a combined stream within the reactor. For example, the reactor may be fed with a feed stream comprising oxygen and with another feed stream separately.

[0057] Furthermore, in the ODH step of the process of the present invention, suitably during the contact of oxygen and ethane with an ODH catalyst, the temperature is 300 to 500 °C. More preferably, said temperature is 310 to 450°C, more preferably 320 to 420°C, most preferably 330 to 420°C.

[0058] Still further, in the ODH step mentioned above, suitably during the contact of oxygen and ethane with an ODH catalyst, typical pressures are 0.01 to 3.0 or 0.01 to 2.0 MPaa (i.e. , “absolute MPa”) (0.1 to 30 or 0.1 to 20 bara, that is, “absolute bar”). Furthermore, preferably, said pressure is 0.01 to 1.5 MPaa (0.1 to 15 bara), more preferably, 0.1 to 8.0 MPaa (1 to 8 bara), with maximum preferably from 0.3 to 8.0 MPaa (3 to 8 bara).

[0059] The product of the ODH step mentioned above comprises the dehydrogenated equivalent of ethane, that is, ethylene. Ethylene is initially formed in said step. However, in said same step, ethylene can be further oxidized under the same conditions to carboxylic acid, i.e. acetic acid.

[0060] In addition to oxygen and ethane, the ODH reactor can also be fed with an inert gas. Said inert gas can be selected from the group consisting of noble gases and nitrogen (N2). Preferably, the inert gas is nitrogen or argon, more preferably nitrogen. Said oxygen is an oxidizing agent, thus resulting in oxidative dehydrogenation of ethane. Said oxygen can originate from any source, such as, for example, air. Ranges for the molar ratio of oxygen to ethane that are inappropriate are 0.01 to 1, more suitably 0.05 to 0.5. The so-called oxygen to ethane ratio is the ratio before the oxygen and ethane come into contact with the catalyst. In other words, the said ratio of oxygen to ethane is the ratio of oxygen as fed to ethane. Obviously, after contact with the catalyst, at least part of the oxygen and ethane is consumed.

[0061] Preferably, in the ODH step of the process of the present invention, the ODH catalyst is a heterogeneous catalyst. Furthermore, preferably, the ODH catalyst is a mixed metal oxide catalyst containing molybdenum, vanadium, niobium and optionally tellerium as the metals, and the catalyst may have the following formula: Mo1VaTebNbcOn where: a, b, c and n represent the ratio between the molar quantity of the element in question and the molar quantity of molybdenum (Mo); a (for V) is 0.01 to 1, preferably 0.05 to 0.60, more preferably 0.10 to 0.40, most preferably 0.20 to 0.35, with maximum preference 0.25 to 0.30; b (for Te) is 0 or >0 to 1, preferably 0.01 to 0.40, more preferably 0.05 to 0.30, most preferably 0.05 to 0.20, with maximum preference 0.09 to 0.15; c (for Nb) is >0 to 1, preferably 0.01 to 0.40, more preferably 0.05 to 0.30, most preferably 0.10 to 0.25, most preferably 0 .14 to .20; and n (for O) is a number that is determined by the valence and frequency of elements other than oxygen.

[0062] The amount of catalyst in the ODH step mentioned above is not essential. Preferably, a catalytically effective amount of the catalyst is used, that is, an amount sufficient to promote the ethane oxydehydrogenation reaction.

[0063] The ODH reactor that can be used in the above-mentioned ODH step can be any reactor, including fixed bed and fluidized bed reactors. Suitably, the reactor is a fixed bed reactor.

[0064] Examples of oxyhydrogenation processes, including catalysts and process conditions are disclosed, for example, in documents No. US7091377, WO2003064035, US20040147393, WO2010096909 and US20100256432, the disclosures of which are incorporated by reference in this document.

[0065] Water is formed during the ethane ODH reaction that occurs in the ODH step of the present process. In the process of the present invention, a water condensing unit which is part of the ODH configuration is fed with a stream comprising unconverted ethane, ethylene and water, suitably the stream comprising unconverted ethane, ethylene and water resulting from said ODH step, and water is removed from said stream by condensation in the water condensing unit, resulting in a stream comprising unconverted ethane and ethylene. In said water condensation step, the water in the stream comprising unconverted ethane, ethylene and water can be easily condensed by cooling the latter stream to a lower temperature, for example, room temperature, after which the condensed water can be separated from the stream comprising unconverted ethane, ethylene and water.

[0066] In the present invention, any carbon dioxide can be removed from carbon dioxide-containing streams by any of the well-known methods. As mentioned above, a carbon dioxide removal agent with which a carbon dioxide removal unit can be fed can be an aqueous solution of a base, for example, sodium hydroxide or an amine. After such removal of carbon dioxide, the stream must be dried in a drying unit to remove residual water from the stream. Placing an aqueous solution of an amine in contact with a current-containing carbon dioxide is preferred in a case where the amount of carbon dioxide is relatively high, for example, in the case of an ethane effluent of ODH. Placing an aqueous solution of sodium hydroxide in contact with a current-containing carbon dioxide is preferred in a case where the amount of carbon dioxide is relatively low, for example, 1) in the case of a cracker effluent at ethane vapor or 2) in the case of an ODH effluent ethane that has been treated with an aqueous solution of an amine and still contains some residual carbon dioxide. In the present invention, a carbon dioxide removal unit as part of the steam cracker configuration may comprise a subunit in which the carbon dioxide is removed by an aqueous solution of an amine and a downstream subunit in which the carbon dioxide is removed. is removed by an aqueous solution of sodium hydroxide. In the latter case, it may be preferred that the first subunit is fed with the carbon dioxide containing effluent from the water condensing unit of the ODH configuration, with the carbon dioxide being removed by an aqueous solution of an amine. Furthermore, a carbon dioxide removal unit as part of the steam cracker configuration may comprise only a unit in which carbon dioxide is removed by an aqueous sodium hydroxide solution. In the latter case, it may be preferred that a carbon dioxide removal unit as part of the ODH configuration is fed with carbon dioxide containing effluent from the water condensing unit of the ODH configuration, with the carbon dioxide being removed. by an aqueous solution of an amine and then the carbon dioxide removal unit of the steam cracker configuration, with the carbon dioxide being removed by an aqueous solution of sodium hydroxide.

[0067] Furthermore, the present invention relates to a chemical complex that is suitable for carrying out the above-described ethylene production process of the present invention, more particularly, a chemical complex comprising a steam cracker configuration and a steam cracker configuration. oxidative dehydrogenation (ODH), wherein: the steam cracker configuration comprises a steam cracking unit, a carbon dioxide removal unit, an optional drying unit, a 1st separation unit, a 2nd separation unit, an optional acetylene hydrogenation unit and a C2 separation unit, each unit comprising one or more feed lines and one or more effluent lines; The ODH configuration comprises an ODH unit, a water condensing unit, an optional carbon dioxide removal unit and an optional drying unit, each unit comprising one or more supply lines and one or more supply lines. effluent; the ODH configuration is integrated into the steam crackers configuration in a position upstream of the optional acetylene hydrogenation unit and upstream of the C2 separation unit; and no ODH unit feed line is integrated with a feed line or effluent line of a steam cracker configuration unit, with the exception that a steam cracking unit feed line and a steam cracker feed line of the ODH unit can be integrated and/or that an optional recycling effluent line from the C2 separation unit and an ODH unit feed line can be integrated.

[0068] Suitably, in the chemical complex described above, the steam cracker configuration comprises the following units in the following order starting from upstream to downstream: a steam cracking unit, a carbon dioxide removal unit, an optional drying unit, a 1st separation unit, a 2nd separation unit, an optional acetylene hydrogenation unit and a C2 separation unit. Furthermore, the steam cracker configuration may comprise a quench cooling unit (quench tower) and/or 1 or more compression units (compressors).

[0069] Furthermore, suitably, in the chemical complex described above, the ODH configuration comprises the following units in the following order starting from upstream to downstream: an ODH unit, a water condensing unit, a water removal unit optional carbon dioxide and an optional drying unit. Furthermore, the ODH configuration may comprise an oxygen removal unit and/or 1 or more compression units (compressors).

[0070] In a first embodiment of the chemical complex described above, the 1st separation unit is a separation unit that is suitable for separating a stream comprising C3+ hydrocarbons, C2 hydrocarbons, hydrogen, optionally carbon monoxide and optionally methane into a stream comprising hydrogen, optionally carbon monoxide and optionally methane and a stream comprising C2+ hydrocarbons; and the 2nd separation unit is a separation unit that is suitable for separating the stream comprising C2+ hydrocarbons into a stream comprising C2 hydrocarbons and a stream comprising C3+ hydrocarbons.

[0071] In a second embodiment of the chemical complex described above, the 1st separation unit is a separation unit that is suitable for separating a stream comprising C3+ hydrocarbons, C2 hydrocarbons, hydrogen, optionally carbon monoxide and optionally methane into a stream comprising C2 hydrocarbons, hydrogen, optionally carbon monoxide and optionally methane and a stream comprising C3+ hydrocarbons; and the 2nd separation unit is a separation unit that is suitable for separating the stream comprising C2 hydrocarbons, hydrogen, optionally carbon monoxide and optionally methane into a stream comprising hydrogen, optionally carbon monoxide and optionally methane and the stream comprising comprises C2 hydrocarbons.

[0072] All features and embodiments as described above with respect to the steam cracker configuration and the ODH configuration, including units thereof, as used in the process of the present invention, also apply to the corresponding configurations and units in the chemical complex of the present invention.

[0073] In particular, in the chemical complex of the present invention, an effluent line from a unit of the ODH configuration can be integrated with a feed line or effluent line from a unit of the steam cracker configuration. Within the present specification, the "integration" of a line of the ODH configuration with a line of the steam cracker configuration in the chemical complex of the present invention means that the two lines in question are connected.

[0074] In the chemical complex of the present invention, the effluent line of a unit of the ODH configuration that may be integrated with a feed line or effluent line of a unit of the steam cracker configuration may be one or more of the following: a) an effluent line from the water condensing unit; b) an optional carbon dioxide removal unit effluent line; and c) an optional drying unit effluent line.

[0075] In the chemical complex of the present invention, an effluent line from the water condensing unit of the ODH configuration can be integrated with a supply line from the carbon dioxide removal unit of the steam cracker configuration.

[0076] In the chemical complex of the present invention, an effluent line from the optional carbon dioxide removal unit of the ODH configuration can be integrated with a feed line from the optional drying unit of the steam cracker configuration.

[0077] In the first embodiment of the chemical complex of the present invention mentioned above, an effluent line of the optional drying unit of the ODH configuration can be integrated with a feed line of the 1st separation unit of the steam cracker configuration.

[0078] In the second embodiment of the chemical complex of the present invention mentioned above, an effluent line of the optional drying unit of the ODH configuration can be integrated with a feed line of the 2nd separation unit of the steam cracker configuration.

[0079] The process and chemical complex of the present invention are further illustrated by Figures 1 to 3.

[0080] In Figure 1, a configuration of steam crackers is shown. Said configuration of steam crackers comprises steam cracking unit 2, a carbon dioxide removal unit 4, drying unit 8, separation units 11, 15, 19 and 24 and the acetylene hydrogenation unit 22. All said separation units 11, 15, 19 and 24 are distillation columns. Furthermore, in Figure 1, an oxidative dehydrogenation (ODH) configuration integrated with said steam cracker configuration is also shown. Said ODH configuration comprises the ODH unit 31 and water condensation unit 33.

[0081] In said Figure 1, the stream 1 comprising ethane is fed to the steam cracking unit 2 which operates under steam cracking conditions. The stream 3 departing from the steam cracking unit 2 comprises C3+ hydrocarbons, ethane, ethylene, acetylene, methane, hydrogen, carbon monoxide and carbon dioxide. The carbon dioxide removal unit 4 is fed with said stream 3. The carbon dioxide removal unit 4 is fed with the carbon dioxide removal agent by means of the stream 5. Said carbon dioxide removal agent carbon dioxide may be an aqueous solution of a base, for example sodium hydroxide or an amine. The carbon dioxide removal unit 4 may comprise a subunit wherein carbon dioxide is removed by an aqueous solution of an amine and the downstream subunit wherein carbon dioxide is removed by an aqueous solution of sodium hydroxide. . The carbon dioxide is removed by an aqueous stream 6. The drying unit 8 is fed with the stream 7 departing from the carbon dioxide removal unit 4, which comprises C3+ hydrocarbons, ethane, ethylene, acetylene, methane, hydrogen, carbon monoxide and water. In the drying unit 8, water is removed via stream 9. The separation unit 11 is fed with the stream 10 departing from the drying unit 8, which comprises C3+ hydrocarbons, ethane, ethylene, acetylene, methane, hydrogen and carbon monoxide.

[0082] In a 1st embodiment, in the separation unit 11, the stream 10 comprising C3+ hydrocarbons, ethane, ethylene, acetylene, methane, hydrogen and carbon monoxide is separated into a top stream 12 comprising methane, hydrogen and monoxide carbon and a bottom stream 13 comprising C3+ hydrocarbons, ethane, ethylene and acetylene. In said 1st embodiment, the separation unit 15 is fed with stream 13 as stream 14. In the separation unit 15, stream 14 is separated into a top stream 17 comprising ethane, ethylene and acetylene and a bottom stream 16 comprising C3+ hydrocarbons.

[0083] In a 2nd embodiment, in the separation unit 11, the stream 10 comprising C3+ hydrocarbons, ethane, ethylene, acetylene, methane, hydrogen and carbon monoxide is separated into a top stream 12 comprising ethane, ethylene, acetylene , methane, hydrogen and carbon monoxide and a bottom stream 13 comprising C3+ hydrocarbons. In said 2nd embodiment, stream 12 is fed as stream 18 to the separation unit 19. In the separation unit 19, stream 12 is separated into an overhead stream 20 comprising methane, hydrogen and carbon monoxide and a stream bottom 21 comprising ethane, ethylene and acetylene.

[0084] The acetylene hydrogenation unit 22 is fed with stream 17 comprising ethane, ethylene and acetylene (1st modality mentioned above) or stream 21 comprising ethane, ethylene and acetylene (2nd modality mentioned above). In the acetylene hydrogenation unit 22, acetylene is hydrogenated using hydrogen stream 22a in ethylene, which results in stream 23 comprising ethane and ethylene. The separation unit 24 (a “C2 separation unit”) is fed with said stream 23, the stream 23 being separated into a top stream 25 comprising ethylene and a bottom stream 26 comprising ethane.

[0085] Furthermore, in said Figure 1, an ODH unit 31 containing an ODH catalyst and operating under ODH conditions is fed with stream 28 comprising ethane and stream 30 comprising an oxidizing agent. The source of ethane, with which the steam cracking unit 2 and ODH unit 31 are fed, can be the same or different. In a case where the source is the same, the ODH unit 31 can be fed with ethane from stream 1 via stream 29 and stream 28. The product stream 32 departing from the ODH unit 31 comprises water, ethane, ethylene, acetylene, carbon monoxide, carbon dioxide and any acetic acid. Said stream 32 is fed to the water condensing unit 33. In the water condensing unit 33, water and any acetic acid are removed by condensation through the stream 34. In Figure 1, the carbon dioxide removal unit 4 which is part of the steam cracker configuration is fed with the stream 35 from the water condensing unit 33, which comprises ethane, ethylene, acetylene, carbon monoxide and carbon dioxide. Additionally, before feeding the carbon dioxide removal unit 4 with stream 35, another carbon dioxide removal unit (not shown in Figure 1) that is not part of the steam cracker configuration may first be fed with the stream 35, in which a relatively greater amount of carbon dioxide can be removed than in the carbon dioxide removal unit 4, for example, with the use of an aqueous solution of an amine as a carbon dioxide removal agent. Generally speaking, the effluent from an ODH unit contains relatively more carbon dioxide than the effluent from a steam cracking unit. In the latter case, the carbon dioxide removal unit 4 may comprise only a unit in which carbon dioxide is removed by an aqueous sodium hydroxide solution.

[0086] Still further, in said Figure 1, the ethane stream 26 can be recycled by means of the stream 27. The steam cracking unit 2 can be fed with the stream 27a which departs from the stream 27 and which comprises ethane. The ODH unit 31 can be fed with stream 27b which starts from stream 27 and which comprises ethane.

[0087] In Figure 2, the steam cracker configuration and an oxidative dehydrogenation (ODH) configuration integrated with said steam cracker configuration are shown. The configuration of steam crackers is identical to that in Figure 1. In Figure 2, the ODH configuration comprises the ODH unit 31, water condensing unit 33 and carbon dioxide removal unit 37.

[0088] The process of Figure 2 is the same as the process of Figure 1, with the exception that stream 35 which starts from the water condensing unit 33 which is part of the ODH configuration, with the carbon dioxide removal unit 4 which is part of the steam cracker configuration is not fed with the stream 35 comprising ethane, ethylene, acetylene, carbon monoxide and carbon dioxide, however, through the stream 36, the carbon dioxide removal unit 37 which is part of the ODH configuration is fed to it. The carbon dioxide removal unit 37 is fed with the carbon dioxide removal agent via stream 38. Said carbon dioxide removal agent may be an aqueous solution of a base, for example sodium hydroxide. or an amine. Carbon dioxide is removed via aqueous stream 39. In Figure 2, the drying unit 8 which is part of the steam cracker configuration is fed with stream 40 which runs from the carbon dioxide removal unit 37, which comprises ethane, ethylene, acetylene, carbon monoxide and water. In Figure 2, the carbon dioxide removal unit 4 may comprise only a unit in which carbon dioxide is removed by an aqueous sodium hydroxide solution. Furthermore, in Figure 2, carbon dioxide removal unit 37 may comprise a subunit wherein carbon dioxide is removed by an aqueous solution of an amine and the downstream subunit wherein carbon dioxide is removed by an amine. aqueous sodium hydroxide solution.

[0089] In Figure 3, the steam cracker configuration and an oxidative dehydrogenation (ODH) configuration integrated with said steam cracker configuration are shown. The configuration of steam crackers is identical to that in Figures 1 and 2. In Figure 3, the ODH configuration comprises ODH unit 31, water condensing unit 33 and carbon dioxide removal unit 37 and drying unit 42 .

[0090] The process of Figure 3 is the same as the process of Figure 2, with the exception that the drying unit 8 that is part of the steam cracker configuration is not fed with the stream 40 that starts from the carbon dioxide removal unit. carbon 37 which is part of the ODH configuration, with stream 40 comprising ethane, ethylene, acetylene and carbon monoxide, however, through stream 41, the drying unit 42 which is part of the ODH configuration is fed with the same. In the drying unit 42, water is removed via stream 43. Stream 44 from the drying unit 42 comprises ethane, ethylene, acetylene and carbon monoxide. In a 1st embodiment of Figure 3, which corresponds to the 1st embodiment as described with respect to Figure 1, stream 44 is sent with stream 45 to the separation unit 11 which is part of the steam cracker configuration. In a 2nd embodiment of Figure 3, which corresponds to the 2nd embodiment as described with respect to Figure 1, stream 44 is sent with stream 46 to separation unit 19 which is part of the steam cracker configuration.

[0091] In Figures 1 to 3, the steam cracker configuration may comprise one or more compressors (not shown in Figures 1 to 3). A compressor can be placed between the steam cracking unit 2 and the carbon dioxide removal unit 4. In Figure 1, said compressor can be placed between the steam cracking unit 2 and the point at which the streams 3 and 35 are combined. Furthermore, another compressor can be placed between the carbon dioxide removal unit 4 and the drying unit 8. In Figure 2, said compressor can be placed between the drying unit 8 and at the point at which streams 7 and 40 are combined.

[0092] Furthermore, in Figures 1 to 3, the acetylene hydrogenation unit 22 that is part of the steam cracker configuration can be placed in another position within the steam cracker configuration. In Figure 1, the acetylene hydrogenation unit 22 may be placed in one of the following positions (not shown in Figure 1): 1) between the carbon dioxide removal unit 4 and the point at which streams 3 and 35 are combined; 2) between carbon dioxide removal unit 4 and drying unit 8; 3) between the drying unit 8 and the separation unit 11; 4) between separation units 11 and 19 (only in the 2nd modality, as described in relation to Figure 1). In Figure 2, the acetylene hydrogenation unit 22 can be placed in any of the following positions (not shown in Figure 2): 1) between the drying unit 8 and the point at which streams 7 and 40 are combined; 2) between the drying unit 8 and the separation unit 11; 3) between separation units 11 and 19 (only in the 2nd modality, as described in relation to Figure 1). In Figure 3, the acetylene hydrogenation unit 22 can be placed in any of the following positions (not shown in Figure 3): 1) between the separation unit 11 and the point at which streams 10 and 45 are combined (in Figure 3 only). 1st modality as described in relation to Figure 1); 2) between the separation unit 19 and the point at which the streams 18 and 46 are combined (only in the 2nd embodiment, as described with respect to Figure 1). In all other cases, advantageously, the acetylene hydrogenation unit 22 does not need to be fed with any separate hydrogen stream 22a, since hydrogen is still present in said streams 3, 7, 10 and 18.

[0093] In an additional embodiment (not shown in Figures 1 to 3), a feed comprising fresh ethane and, optionally, propane is introduced in the downstream section of the steam crackers configuration, in particular, in line 10 for column 11 or in line 14 to column 15, whereby any propane from the fresh ethane feed is advantageously removed along with any C3+ hydrocarbons originating from the steam cracking unit, thereby eliminating the need to use a separate additional depropanizer. In said additional embodiment, the ODH reactor 31 does not have to be fed directly with fresh ethane, however an ethane recycling from line 27 may be sufficient. Said ethane recycling from line 27 still comprises fresh ethane, that is, the fresh ethane with which column 11 or 15 is fed, the ethane having not been subjected to steam cracking conditions nor to oxidative dehydrogenation conditions ( ODH). Thus, the fresh ethane, with which the ODH unit was fed in the aforementioned manner (i.e., indirectly via line 10 or line 14), originates from a source other than a source of fresh ethane that is used to feed the steam cracking unit directly with ethane. Furthermore, said ethane recycling of line 27 comprises unconverted ethane, that is, unconverted ethane originating from the steam cracking unit.

[0094] The present invention is also applicable to a process in which, instead of subjecting a stream comprising ethane to steam cracking conditions, a stream comprising naphtha is subjected to steam cracking conditions in the steam cracking unit. which is part of the steam cracker configuration of the present invention. The above-mentioned embodiments and preferences regarding ethane vapor cracking apply the same as the above case in which a naphtha vapor cracker configuration and an ODH configuration are integrated. Generally speaking, the stream resulting from a naphtha steam cracker is subjected to a quenching step in which cooling and removal of heavy matter are carried out. Such a quenching step can be included between units 2 and 4 in Figures 1 to 3.

Claims (4)

1. Process for producing ethylene from ethane, characterized by the fact that it comprises the following steps: subjecting a stream (1) comprising ethane to steam cracking conditions in a steam cracking unit (2) which is part of a steam cracker configuration, resulting in a stream (3) comprising unconverted ethane, ethylene, hydrogen, methane, carbon monoxide, carbon dioxide and C3+ hydrocarbons; feed, with a stream comprising unconverted ethane, ethylene, hydrogen, methane, carbon monoxide, carbon dioxide and C3+ hydrocarbons, a carbon dioxide removal unit (4), which is part of the steam cracker configuration, and removing carbon dioxide from the stream in the carbon dioxide removal unit (4), resulting in a stream (7) comprising unconverted ethane, ethylene, hydrogen, methane, carbon monoxide and C3+ hydrocarbons; feed, with a stream comprising unconverted ethane, ethylene, hydrogen, methane, carbon monoxide and C3+ hydrocarbons, a separation unit (11), which is part of the steam cracker configuration, and separate the stream in the separation unit (11) in a stream (12) comprising hydrogen, methane and carbon monoxide and a stream (13) comprising C3+ hydrocarbons; food, with unconverted ethane and ethylene from a stream comprising unconverted ethane, ethylene, hydrogen, methane, carbon monoxide and C3+ hydrocarbons, a C2 separation unit (24), which is part of the steam cracker configuration, and separating the stream in the C2 separation unit (24) into a stream (25) comprising ethylene and a stream comprising unconverted ethane (26); subjecting a stream comprising ethane (28) to oxidative dehydrogenation (ODH) conditions in an ODH unit (31), which is part of an ODH configuration, resulting in a stream (32) comprising unconverted ethane, ethylene, water, carbon monoxide and carbon dioxide; feed, with a stream (32) comprising unconverted ethane, ethylene, water, carbon monoxide and carbon dioxide, a water condensing unit (33), which is part of the ODH configuration, and remove water from the stream by condensing medium in the water condensing unit (33), resulting in a stream (35) comprising unconverted ethane, ethylene, carbon monoxide and carbon dioxide; feeding, with an effluent originating from the ODH configuration, which effluent comprises unconverted ethane and ethylene, the steam cracker configuration, in a position that is downstream of the steam cracking unit (2); and wherein: 1) in a first embodiment, the stream comprising unconverted ethane, ethylene, hydrogen, methane, carbon monoxide and C3+ hydrocarbons is separated in the separation unit (11) into a stream (12) comprising hydrogen, methane and carbon monoxide and a stream (13) comprising C2+ hydrocarbons, which C2+ hydrocarbons comprise unconverted ethane, ethylene and C3+ hydrocarbons; the separated stream (13) comprising C2+ hydrocarbons is fed into a further separation unit (15), wherein the stream is separated into a stream (17) comprising C2 hydrocarbons, the C2 hydrocarbons of which comprise unconverted ethane and ethylene, and a chain (16) comprising C3+ hydrocarbons; and the separated stream (17) comprising C2 hydrocarbons from the additional separation unit (15) is fed into the C2 separation unit (24), wherein the latter stream is separated into a stream (25) comprising ethylene and a stream (26) comprising unconverted ethane; or 2) in a second embodiment, the stream comprising unconverted ethane, ethylene, hydrogen, methane, carbon monoxide and C3+ hydrocarbons is separated in the separation unit (11) into a stream (12) comprising hydrogen, methane, monoxide carbon and C2 hydrocarbons, which C2 hydrocarbons comprise unconverted ethane and ethylene, and a stream (13) comprising C3+ hydrocarbons; the separated stream (12) comprising hydrogen, methane, carbon monoxide and C2 hydrocarbons is fed into an additional separation unit (19), wherein the stream is separated into a stream (20) comprising hydrogen, methane and carbon monoxide. carbon and a chain (21) comprising C2 hydrocarbons; and the separated stream (21) comprising C2 hydrocarbons from the additional separation unit (19) is fed into the C2 separation unit (24), wherein the latter stream is separated into a stream (25) comprising ethylene and a stream (26) comprising unconverted ethane; and wherein: unconverted ethane and ethylene from the stream (35) comprising unconverted ethane and ethylene from the water condensing unit (33) of the ODH configuration are fed into the C2 separation unit (24) of the cracker configuration a steam. 2. Process according to claim 1, characterized by the fact that ethane is fed into the ODH unit (31) that originates from one or more sources selected from the group consisting of a) the source of fresh ethane that is used to feed ethane into the steam cracking unit (2); b) another source of fresh ethane, different from the first source mentioned in a); and c) unconverted ethane from an effluent originating from the C2 separation unit (24). 3. Process, according to any one of claims 1 or 2, characterized by the fact that the stream (3) originating from the steam cracking unit (2), of the steam cracker configuration, additionally comprises acetylene; the stream (32) originating from the ODH unit (31), of the ODH configuration, additionally comprises acetylene; and the process comprises the following additional step: an acetylene hydrogenation step wherein, in an acetylene hydrogenation unit (22), which forms part of the steam cracker configuration, a stream (17, 21) comprising ethane is not converted, ethylene and acetylene is subjected to hydrogenation conditions in order to convert acetylene into ethylene. 4. Chemical complex for the process of producing ethylene from ethane as defined in any one of claims 1 to 3, characterized in that it comprises a steam cracker configuration and an oxidative dehydrogenation (ODH) configuration, in which : the steam cracker configuration comprises the following units, in the following order, going from upstream to downstream: a steam cracking unit (2), a carbon dioxide removal unit (4), an optional drying unit ( 8), a first separation unit (11), a second separation unit (15, 19), an optional acetylene hydrogenation unit (22) and a C2 separation unit (24), each unit comprising a or more supply lines and one or more effluent lines; the ODH configuration comprises the following units, in the following order, going from upstream to downstream: an ODH unit (31), a water condensing unit (33), an optional carbon dioxide removal unit (37) and an optional drying unit (42), each unit comprising one or more supply lines and one or more effluent lines; the ODH configuration is integrated with the steam crackers configuration at a position upstream of the optional acetylene hydrogenation unit (22) and upstream of the C2 separation unit (24); and no ODH unit feed line (31) is integrated with a feed line or effluent line of a unit of the steam crackers configuration, with the exception that a steam cracker unit feed line (2 ) and an ODH unit feed line (31) can be integrated, and/or that an optional C2 separation unit recycling effluent line (24) and an ODH unit feed line (31) can be integrated; and wherein: 1) in a first embodiment, the first separation unit (11) is a separation unit that is suitable for separating a stream comprising C3+ hydrocarbons, C2 hydrocarbons and hydrogen into a stream comprising hydrogen (12) and a stream comprising C2+ hydrocarbons (13); and the second separation unit (15) is a separation unit which is suitable for separating a stream (14) comprising C2+ hydrocarbons into a stream (17) comprising C2 hydrocarbons and a stream (16) comprising C3+ hydrocarbons; or 2) in a second embodiment, the first separation unit (11) is a separation unit that is suitable for separating a stream comprising C3+ hydrocarbons, C2 hydrocarbons and hydrogen into a stream (12) comprising C2 hydrocarbons and hydrogen and a stream (13) comprising C3+ hydrocarbons; and the second separation unit (19) is a separation unit which is suitable for separating a stream (18) comprising C2 hydrocarbons and hydrogen into a stream (20) comprising hydrogen and a stream (21) comprising C2 hydrocarbons; and wherein: a) an effluent line from the water condensing unit (33) of the ODH configuration is integrated with a feed line from the carbon dioxide removal unit (4) of the steam crackers configuration; or b) the steam cracker configuration comprises a drying unit (8) and the ODH configuration comprises a carbon dioxide removal unit (37), and an effluent line from the carbon dioxide removal unit (37 ) of the ODH configuration is integrated with a feed line from the drying unit (8) of the steam crackers configuration; or c) the ODH configuration comprises a drying unit (42) and, in the first embodiment, an effluent line from the drying unit (42) of the ODH configuration is integrated with a feed line of the first separation unit (11 ) of the configuration of steam crackers; or d) the ODH configuration comprises a drying unit (42) and, in the second embodiment, an effluent line from the drying unit (42) of the ODH configuration is integrated with a feed line of the second separation unit (19 ) of the configuration of steam crackers.