Method and plant for provision of a hydrogen fraction

Abstract

The invention relates to a method for obtaining a hydrogen fraction from a mixture of hydrogen, methane and higher hydrocarbons. First, the mixture undergoes a first condensation at -95 °C to -100 °C, in order to obtain a condensed and a non-condensed portion. A second condensation step is carried out at -130 °C to -150 °C. Then, a pressure swing adsorption is carried out to extract pure hydrogen gas and to leave behind a residual gas. The second condensation step uses the residual gas and a portion of the condensed gas from the second condensation. The formation of the second condensation step involves compressing the residual gas and expanding, evaporating and condensing the fed-back condensed portion. In addition, there is a heat exchange between the second condensed feed and the fed-back amount. The invention also relates to a corresponding plant.

Description

Description Process and plant for providing a hydrogen fraction The invention relates to a process and a plant for providing a hydrogen fraction. background Processes and plants for steam cracking hydrocarbons are described, for example, in the article "Ethylene" in Ullmann's Encyclopedia of Industrial Chemistry, online edition, April 15, 2009, DOI: 10.1002 / 14356007. a10_045.pub2. Steam cracking is primarily used to produce short-chain olefins such as ethylene and propylene, diolefins such as butadiene, or aromatics, but is not limited to the production of such compounds. Steam cracking produces component mixtures (also known as cracked gases or raw gases), which are then subjected to suitable processing sequences to obtain the desired individual components. Typically, the first section (front-end section) of a corresponding processing sequence involves the removal of heavy compounds, if present, followed by raw gas compression and acid gas removal. After processing in the first section, fractionation follows, in which different fractions are formed using thermal separation processes and further separated if necessary. For details, see the aforementioned article "Ethylene" in Ullmann's Encyclopedia of Industrial Chemistry, particularly sections 5.3.2.1, "Front-End Section," and 5.3.2.2, "Hydrocarbon Fractionation Section." Corresponding processing sequences can in particular comprise demethanisation and deethanisation in the specified order or in reverse order, as described, for example, in EP 3 940 042 A1 with reference to the prior art in paragraphs

[0004] until

[0009] disclosed. Express reference is made here to the disclosure content of these paragraphs, in particular with regard to the meaning of the terms used herein. EP 3 940 042 A1 proposes a process in which demethanization steps are followed by a non-cryogenic separation, such as pressure swing adsorption. This method can be used to obtain, for example, a hydrogen fraction. US 2020 / 307997 A1 discloses a process for the combined production of hydrogen and carbon dioxide from a hydrocarbon mixture, in which the residual gas from a pressure swing adsorption is separated by permeation to reduce its hydrocarbon content, and the resulting gas is separated at low temperature to produce a carbon dioxide-rich liquid. EP 2 727 979 A1 discloses a process for producing hydrocarbons from biomass, in which a feed stream from biomass gasification or from another synthesis gas production process is fed to a first membrane stage to form a permeate stream comprising water vapor and carbon dioxide and a retentate stream comprising hydrogen and carbon monoxide, the retentate stream of the first membrane stage is fed to a Fischer-Tropsch reactor, the product stream is fed to a second membrane stage to form a permeate stream comprising water vapor and hydrogen and a retentate stream comprising hydrocarbons, the permeate stream of the second membrane stage is fed to the reactor, the retentate stream of the second membrane stage is fed to a separator stage, and the gas phase of the separator stage is fed to a third membrane stage. According to US 5,634,354 A, olefins are recovered from thermally cracked gas or by fluid catalytic cracking by cooling the gas to condense a portion of the hydrocarbons, removing hydrogen from the uncondensed gas, and condensing the remaining hydrocarbons in a cold condensation zone with a dephlegmator operating above about -166°F. Hydrogen is removed from the uncondensed gas in a process selected from polymer membrane permeation, adsorptive membrane permeation, or pressure swing adsorption. There is still a need for improved processes and plants of this type for the provision of hydrogen fractions. Disclosure of the invention Against this background, a process and a plant for providing a hydrogen fraction having the features of the independent patent claims are proposed. Further embodiments are the subject of the dependent patent claims and the following description. Before explaining the advantages of the present invention, some terms used in describing the invention are defined in more detail below. Mixtures of components (also referred to herein as fractions) may be rich or poor in one or more components, where the term "rich" may mean a content of at least 75%, 80%, 90%, 95% or 99% and the term "poor" may mean a content of at most 25%, 20%, 10%, 5% or 1% on a molar, weight or volume basis. In the language used here, component mixtures may also be enriched or depleted in one or more components, these terms referring to a corresponding content in another component mixture using which the component mixture in question was formed. The component mixture in question is "enriched" if it contains at least 1.5 times, 2 times, 5 times, 10 times, 100 times, or 1,000 times the specified components, and "depleted" if it contains at most 0.75 times, 0.5 times, 0.1 times, 0.01 times, or 0.001 times the specified components. A component mixture that "predominantly" contains one or more components is particularly rich in these components in the sense just explained. If, for example, hydrogen or methane is mentioned here, this can also refer to a fraction that is rich in the corresponding component. When it is mentioned here that a component mixture is "formed" using another component mixture, this is understood to mean that the component mixture in question comprises at least some of the components contained in or formed from the other component mixture. Forming one component mixture from another can, for example, comprise branching off part of the component mixture, adding one or more further components or component mixtures, chemically or physically reacting at least some components, as well as heating, cooling, evaporating, condensing, etc. "Forming" a component mixture from another component mixture can, however, also merely comprise providing the other component mixture in a suitable form, for example in a container or a line. This application uses the terms "pressure level" and "temperature level" to characterize pressures and temperatures. This is intended to express that corresponding pressures and temperatures in a corresponding system do not have to be used in the form of exact pressure or temperature values. However, such pressures and temperatures typically fluctuate within certain ranges, for example, within ± 1%, 5%, 10%, 20%, or 25% of a mean value. Corresponding pressure levels and temperature levels can lie in disjoint ranges or in ranges that overlap one another. The same pressure level can, for example, still exist when unavoidable pressure losses occur. The same applies to temperature levels. The pressure levels specified here in bar are absolute pressures. For the design and specific configuration of columns, columns, and other separation apparatus, as well as their internals, as may also be used in the present application, reference is expressly made to relevant specialist literature (see, for example, Sattler, K.: Thermal Separation Processes: Fundamentals, Design, Apparatus, 3rd edition 2001, Weinheim, Wiley-VCH). In particular, corresponding separation apparatus can have conventional trays, particularly in the form of structured plates with drainage devices, or suitable packings. When the term “demethanation” is used below, it is intended to be used briefly for a Separation step in which hydrocarbons with two or two or more Carbon atoms of lower-boiling compounds, in particular methane and hydrogen, are separated from a component mixture fed to the demethanization, i.e. a “feed mixture” for demethanization. During demethanization, a fraction is conventionally obtained which, depending on the composition of the feed mixture fed to the demethanization, contains hydrocarbons with two or two or more carbon atoms and is always poor in or free from lower-boiling components, in particular methane and hydrogen. This fraction is typically obtained in the liquid state and is also referred to as the “heavy fraction”. During demethanization, a fraction is also obtained which contains the aforementioned lower-boiling compounds and is poor in or free from hydrocarbons with two or two or more carbon atoms. This fraction is typically obtained in the gaseous state and is also referred to as the “light fraction”. The present invention proposes a process for providing a hydrogen fraction, in which a separation feed containing hydrogen, methane, and higher hydrocarbons is subjected to separation. In embodiments of the present invention, the separation feed can be formed using at least a portion of a cracked gas produced by steam cracking a hydrocarbon-containing steamer field feed, for example, naphtha or an ethane-rich steamer field feed. The separation feed contains at least a portion of the hydrogen, methane, and higher hydrocarbons from the cracked gas. The separation feed can be formed from the cracked gas using any desired processing steps, which may include, in particular, compression, drying, carbon dioxide removal, and optionally deethanization in any manner known from the prior art. In the separation process, the separation insert is subjected to a first condensation step, obtaining a condensed portion and leaving an uncondensed portion. The first condensation step can be carried out in several stages and can be carried out essentially in a manner comparable to known demethanization processes. This involves a stepwise separation of condensates, each of which is enriched in higher hydrocarbons compared to a gaseous residue, but may still contain certain amounts of methane and hydrogen in dissolved form. Therefore, These condensates are then rectified to obtain essentially “pure” fractions containing methane on the one hand and the higher hydrocarbons on the other, as illustrated and explained in detail in Figure 1 below. In the understanding underlying this paper, the multiple condensates together form the condensed portion. An uncondensed portion remains at the lowest temperature level at the end of the condensation. As an alternative to the multi-stage condensation described above, a single-stage condensation can also be carried out in embodiments of the present invention. In general, the condensed portion can therefore comprise one or more condensate fractions, and the uncondensed portion can comprise one or more uncondensed fractions. During the (stepwise) first condensation, the aforementioned uncondensed fraction remains at the lowest temperature level, especially at approximately -97 °C at a pressure of approximately 30 bar. This fraction typically contains more than 70 mol percent and up to 95 mol percent hydrogen, but also methane. The higher hydrocarbons typically account for less than 20 mol percent of the uncondensed fraction from the first condensation or from the first condensation feed. Within the scope of the present invention, a pressure swing adsorption feed is further subjected to pressure swing adsorption to obtain the hydrogen fraction and a pressure swing adsorption residual gas. The present invention thus combines aspects of demethanization with pressure swing adsorption, which is known in principle but is modified in a particularly advantageous manner in the present invention. The hydrogen fraction is formed at the adsorption pressure of pressure swing adsorption, which can typically be approximately 30 bar. The pressure swing adsorption residual gas is provided at a desorption pressure, typically at a slightly superatmospheric pressure of approximately 1.2 bar, for example. The pressure swing adsorption residual gas has a hydrogen content of 20 to 60 mol percent and a methane content. The present invention now provides that a second condensation feed is subjected to a second condensation, likewise obtaining a condensed portion and leaving an uncondensed portion, wherein the second condensation feed is formed using the pressure swing adsorption residual gas or a portion thereof and a recycle portion of the condensed portion of the second condensation feed. In contrast to the first condensation, the second condensation is carried out at a significantly lower temperature, in particular at approximately -147°C. In this way, a large portion of the methane and higher hydrocarbons contained in the second condensation feed can be condensed. The uncondensed portion of the second condensation feed, on the other hand, can in particular contain a large portion of the hydrogen contained in the second condensation feed.The second condensation can also be carried out in one or more stages, forming one or more condensate fractions and leaving one or more uncondensed fractions, which then form the condensed or uncondensed portion. In the present invention, the pressure swing adsorption feed is formed using the uncondensed portion of the first condensation feed, or a portion thereof, and the uncondensed portion of the second condensation feed, or a portion thereof. In this way, the hydrogen contained therein can also be converted into the hydrogen fraction, resulting in a very good yield. Forming the second condensation insert comprises compressing the pressure swing adsorption residual gas or the portion thereof used to form the second condensation insert, and forming the second condensation insert further comprises expanding, heating, evaporating, and compressing the recycle portion of the condensed portion of the second condensation insert. The compression of the pressure swing adsorption residual gas or the portion thereof used to form the second condensation insert and the recycle portion is carried out in particular using a common compressor, into which the recycle portion is fed, for example, at an intermediate stage. Other configurations are also possible. For the aforementioned compression, embodiments of the present invention can also utilize a geared turbocompressor, in which, for example, each compressor stage, or at least one compressor stage, can be controlled autonomously with an inlet guide vane. This configuration results in particularly efficient operation. Alternatively, a single-shaft turbocompressor can also be used, which particularly reduces construction costs. The second condensation comprises at least one heat transfer from the second condensation insert to the recirculation portion of the condensed portion of the second condensation insert. Within the scope of the present invention, this effectively creates an open refrigeration cycle in which the pressure swing adsorption residual gas is circulated. Previously known processes for extracting hydrogen fractions from fission gases typically suffer from the fact that only approximately 90% of the hydrogen can be extracted as high-purity hydrogen and / or that relatively high hydrogen concentrations are still present in the methane fraction. Furthermore, hydrogen extraction typically requires a "tail-end" hydrogen extraction process, which requires at least one pressure swing adsorption process and usually two additional compressors. Membrane processes typically used in conventional solutions can also be very costly. The proposed solution achieves several objectives simultaneously. On the one hand, a suitable process can recover almost all of the hydrogen in the cracked gas, i.e., more than 95%, as high-purity hydrogen at pressures above 20 bar. Accordingly, a low-hydrogen tail gas fraction can also be produced, which can optionally also be present at elevated pressure, particularly above 10 bar. This objective is achieved with a very compact process design that requires only an additional compressor, a pressure swing adsorption unit, and a cold box. The proposed design achieves a maximum hydrogen yield of, for example, 97% with only a few losses of hydrogen into the methane fraction (since small amounts of hydrogen are released during the condensation). "dissolve" in the liquid phase). The hydrogen is present at high pressure and high purity. The methane fraction formed from the overhead gas of the low-temperature rectification is correspondingly low in hydrogen, which facilitates further processing of the methane, for example, in the production of synthesis gas. The design is comparatively compact and does not require any expanders. As mentioned, only a pressure swing adsorption unit, an additional compressor, a cold box, and (for certain configurations such as the one described below) a small cold pump in the cold part of a corresponding plant are required. The process proposed here also has the particular advantage that only relatively low-hydrogen streams are fed to the compressor in the form of the residual gas from pressure swing adsorption and the recycle portion of the condensed portion of the second condensation feed. This simplifies compressor design due to the relatively high molecular weight. Conventional processes, in contrast, can be disadvantageous, as hydrogen-rich gas may have to be "recompressed" for pressure swing adsorption. This is very energy-intensive due to the low molecular weight. As already mentioned, the present invention can be used in connection with steam cracking processes, but is not limited thereto. In embodiments of the present invention, the process thus comprises forming a cracked gas by steam cracking a hydrocarbon-containing steam cracker feed, wherein the separation feed is provided using the cracked gas or a portion thereof in a processing step, and wherein the hydrogen, the methane, and the higher hydrocarbons each originate at least in part from the cracked gas. In one embodiment of such a process, the upgrading includes deethanization so that the higher hydrocarbons are more than 90% hydrocarbons with two carbon atoms. The first condensation is carried out in the context of the present invention in particular at a first condensation pressure level of 20 to 45 bar, for example approximately 30 bar, and according to the invention at a minimum first condensation temperature level of -95 °C to -100 °C, for example approximately -97 °C. The "minimal" first In a multi-stage condensation process, the condensation temperature level is particularly that of the "final" condensation stage. Generally, a "minimal" first condensation temperature level is the lowest temperature to which a gas stream is exposed to separate condensate(s). A particular advantage here is that corresponding temperatures can be achieved with "conventional" refrigerants such as ethylene. The second condensation is carried out in particular at a second condensation pressure level of 20 to 45 bar, for example approximately 30 bar, and according to the invention at a minimum second condensation temperature level of -130 °C to -150 °C, for example approximately -147 °C. For an understanding of the term "minimal" second condensation temperature level, reference is made to the above explanations regarding the "minimal" first condensation temperature level. The second condensation pressure level is in particular equal to or higher than the first condensation pressure level, so that no intermediate compression is necessary. In corresponding embodiments, lower temperatures than those achievable with ethylene refrigerant are therefore only required for a comparatively small portion. The heating of the uncondensed portion of the first condensation insert or the part thereof used to form the pressure swing adsorption insert and the uncondensed portion of the second condensation insert or the part thereof used to form the pressure swing adsorption insert is carried out in particular to a temperature level above 0 °C, for example substantially ambient temperature, and the heating is carried out in particular at the first condensation pressure level. The condensed portion of the first condensation feed and a portion of the condensed portion of the second condensation feed are subjected, in particular, to low-temperature rectification, as is generally known in deethanization. This can be carried out at a rectification pressure level of 13 to 15 bar, for example, approximately 14 bar. A top fraction, which essentially comprises methane, and a bottom liquid, which essentially comprises the higher hydrocarbons, are formed, with the higher Hydrocarbons in upstream deethanization essentially Hydrocarbons with two carbon atoms or otherwise Include hydrocarbons with more than two carbon atoms. The top gas formed in the low-temperature rectification can be cooled, in particular with heat transfer to the recycle portion, and partially condensed to obtain a condensed and a non-condensed top gas portion, wherein the non-condensed top gas portion or a portion thereof can be heated as methane fraction and removed from the process and the condensed top gas portion or a portion thereof can be recycled as reflux to the low-temperature rectification. In the proposed process, the separation feed can in particular have a content of 20 to 60 mol percent hydrogen, 2 to 20 mol percent methane and 40 to 70 mol percent of higher hydrocarbons. Alternatively or additionally, the uncondensed portion of the first condensation feed can have a content of 70 to 95 mol percent hydrogen, 5 to 30 mol percent methane and 1 to 20 mol percent of higher hydrocarbons. Alternatively or additionally, the hydrogen fraction can have a content of 90 to 100 mol percent hydrogen, 0 to 10 mol percent methane and 0 to 10 mol percent of higher hydrocarbons. Alternatively or additionally, the pressure swing adsorption residual gas can have a content of 20 to 60 mol percent hydrogen, 20 to 60 mol percent methane and 2 to 40 mol percent of higher hydrocarbons.Alternatively or additionally, the uncondensed portion of the second condensation feed may contain 70 to 95 mol percent hydrogen, 5 to 30 mol percent methane, and 1 to 20 mol percent of higher hydrocarbons. Alternatively or additionally, the condensed portion of the second condensation feed may contain 0 to 10 mol percent hydrogen, 40 to 99 mol percent methane, and 10 to 60 mol percent of higher hydrocarbons. The proposed plant for providing a hydrogen fraction comprises a separation arrangement and is designed to subject a separation insert containing hydrogen, methane and higher hydrocarbons to a separation in the separation arrangement and to use the separation insert as a first condensation insert to obtain a condensed portion and to remain to subject an uncondensed portion to a first condensation, to subject a second condensation insert to a second condensation to obtain a condensed portion and to retain an uncondensed portion, to subject a pressure swing adsorption insert to a pressure swing adsorption to obtain the hydrogen fraction and a pressure swing adsorption residual gas, to form the second condensation insert using the pressure swing adsorption residual gas or a portion thereof and a recycle portion of the condensed portion of the second condensation insert, to form the pressure swing adsorption insert using the uncondensed portion of the first condensation insert or a portion thereof and the uncondensed portion of the second condensation insert or a portion thereof,forming the second condensation insert comprises compressing the pressure swing adsorption residual gas or its portion used to form the second condensation insert and expanding, evaporating, and compressing the recycle subset, and the second condensation comprises heat transfer from the second condensation insert to the recycle subset. For further features and advantages of a corresponding system and embodiments thereof, reference is expressly made to the above explanations concerning the method proposed according to the invention and its embodiments, since these apply equally to this. The same applies to a system which, according to an embodiment of the invention, is designed to carry out a method according to any embodiment of the present invention. Short description of the drawing Embodiments of the invention are described below purely by way of example with reference to the accompanying drawings. Figure 1 illustrates a system according to an embodiment of the invention. Embodiments of the invention The embodiments described below are described solely for the purpose of assisting the reader in understanding the claimed and previously discussed features. They are merely representative examples and are not intended to be exhaustive and / or limiting with regard to the features of the invention. It is to be understood that the advantages, embodiments, examples, functions, features, structures, and / or other aspects described above and below are not to be considered as limitations on the scope of the invention as defined in the claims or as limitations on equivalents to the claims, and that other embodiments may be utilized and changes may be made without departing from the scope of the claimed invention. Different embodiments of the invention may include, comprise, consist of, or consist essentially of other useful combinations of the described elements, components, features, parts, steps, means, etc., even if such combinations are not specifically described herein. Furthermore, the disclosure may encompass other inventions that are not currently claimed but that may be claimed in the future, particularly if they are encompassed within the scope of the independent claims. Explanations relating to devices, apparatus, arrangements, systems, etc. according to embodiments of the present invention may also apply to methods, processes, methods, etc. according to the embodiments of the present invention, and vice versa. Elements, method steps, etc. that are identical, have the same effect, are functionally equivalent, are structurally identical, or are comparable may be identified by identical reference numerals. Figure 1 illustrates a method according to an embodiment of the present invention and is designated overall by 100. In the process 100, a cracked gas 102 is formed by steam cracking 10 of a hydrocarbon-containing steam field feed 101 in a manner known per se. This can be subjected to one or more processing or separation steps 20 in a manner also known per se, for example a quench, a Compression, carbon dioxide removal, and drying. The treatment or separation step(s) 20 may also include, for example, a deethanization of a known type. This produces a material stream 103, referred to herein as the "separation feed." The separation insert 103 contains at least hydrogen, methane, and higher hydrocarbons from the cracked gas. When deethanization is used as part of the processing or separation step(s) 20, the higher hydrocarbons comprise essentially or only hydrocarbons with two carbon atoms; in other cases, longer-chain hydrocarbons may also be contained in the separation insert 103. The separation insert 103 is fed to a separation or separation arrangement 30, which comprises known aspects of demethanization. Here, the separation insert 103 is subjected to a multi-stage condensation 31, which is referred to here as the "first condensation." The separation insert 103 is therefore also referred to here as the "first condensation insert." In the first condensation 31, an uncondensed fraction 105 remains, which here forms an "uncondensed portion" of the first condensation insert 103, and several condensates, which together form an "uncondensed portion" and are indicated as 104, are provided. The first condensation takes place here at the previously indicated first condensation pressure level, typically approximately 30 bar, and down to the also mentioned minimum condensation temperature or the first condensation temperature level, typically approximately 97°C. The condensates, i.e., the uncondensed portion of the first condensation feed 103, are expanded and fed to a low-temperature rectification 32, which is carried out at the rectification pressure level also mentioned above, typically approximately 14 bar. A bottoms liquid obtained in the low-temperature rectification 32 is discharged from the process 100 as stream 106. This contains the higher hydrocarbons and is essentially free of hydrogen and methane. A head gas obtained in the low-temperature rectification 32, which is essentially Containing methane, is cooled in a heat exchanger 33 and brought to a suitable condensation temperature level, typically about -146 °C, and correspondingly partially condensed. After a phase separation (not specifically designated), a liquid portion 108 is returned as reflux to the low-temperature rectification 32 by means of a pump (also not specifically designated), whereas a gaseous portion 109 remaining is discharged as methane fraction from the process 100. The portion 109 is heated in the heat exchanger 33 to a corresponding temperature level, typically approximately -97 °C, and then further heated in another heat exchanger 34 to a corresponding temperature level, typically approximately 25 °C. In the heat exchanger 34 and the first condensation 31, which also comprises a heat exchange, suitable refrigerants 110, in particular ethylene refrigerants, are used. After combining the uncondensed portion 105 of the first condensation insert 103 with an uncondensed portion 111 of a second condensation insert 115 (explained further below), a collected stream 112 formed in this way is used in parallel as a refrigerant in the first condensation 31 and is heated in the process and further heated in the heat exchanger 34. Further heating can also be carried out in a "pre-cooling" 35 (e.g., to cool the cracked gas 102 somewhere during the processing step(s) 20). Instead of the illustrated formation of the collected stream 112, corresponding material streams can also be passed through the aforementioned components without being combined. To avoid misunderstandings, it should be emphasized at this point that all heat transfer processes 31, 33, 34 and 35 can be carried out with any heat exchangers in the manner shown here, but also with heat exchangers of other designs and combinations, divided into several heat exchangers, or in combination with one another. The collected stream 112, also referred to here as the "pressure swing adsorption feed," is fed to a pressure swing adsorption unit 36, in which a hydrogen fraction 113 is formed essentially at the first condensation pressure level, as well as a pressure swing adsorption residual gas 114 at a slightly superatmospheric pressure level, in particular approximately 1.2 bar. The pressure swing adsorption residual gas 114 is subjected to compression 37 in several stages down to a corresponding pressure level, typically approximately 30 bar. This pressure level is also referred to here as the "second condensation pressure level." Ideally, the second condensation pressure level is at the same condensation pressure level as the first condensation pressure level or slightly higher, so that the above-described combination of the uncondensed portion 105 of the first condensation insert 103 with the uncondensed portion 111 of the second condensation insert 115, explained further below, can be achieved without any additional effort. A material stream taken from the compressor 37 forms this "second condensation feed" 115. This is cooled in the heat exchangers 34 and 33 to a suitable temperature level, which is also referred to here as the "second condensation temperature level," and partially condensed in the process. After a phase separation (again not specifically designated), a condensate 116, which here forms a "condensed portion" of the second condensation feed 115, is divided into partial streams 117 and 118, with portion 117 being returned to the low-temperature rectification 32. A partial amount 118 thereof, which is also referred to here as the "recycle partial amount," is expanded, evaporated in the heat exchangers 33 and 34, and fed back to the compressor 37 at an intermediate stage and a corresponding pressure level, typically approximately 2.6 bar. The uncondensed portion 111 has already been mentioned and is heated in the heat exchanger 33.

Claims

Patent claims 1. A process (100) for providing a hydrogen fraction (113), in which a separation insert (103) containing hydrogen, methane and higher hydrocarbons is subjected to a separation (30) in which - the separating insert (103) is subjected as a first condensation insert (103) to a first condensation (31) at a minimum first condensation temperature level of -95 °C to -100 °C, while obtaining a condensed portion (104) and leaving an uncondensed portion (105), - a second condensation insert (115) is subjected to a second condensation (34, 33) at a minimum second condensation temperature level of -130 °C to -150 °C, while obtaining a condensed portion (116) and leaving an uncondensed portion (111), - a pressure swing adsorption insert (112) is subjected to pressure swing adsorption (36) to obtain the hydrogen fraction (113) and a pressure swing adsorption residual gas (114), - the second condensation insert (115) is formed using the pressure swing adsorption residual gas (114) or a portion thereof and a recirculation portion (118) of the condensed portion (116) of the second condensation insert (115), - the pressure swing adsorption insert (112) is formed using the uncondensed portion (105) of the first condensation insert (103) or a part thereof and the uncondensed portion of the second condensation insert (111) or a part thereof, - the formation of the second condensation insert (115) comprises compressing (37) the pressure swing adsorption residual gas (114) or its portion used to form the second condensation insert (115) and expanding, evaporating and compressing (37) the recirculation portion (118), and the second condensation (34, 33) comprises a heat transfer from the second condensation insert (115) to the recirculation subset (118).

2. Process according to claim 1, in which a cracked gas (102) is formed by steam cracking (10) a hydrocarbon-containing steamer field feed (101), wherein the separation feed (103) is provided using the cracked gas (102) or a part thereof in a processing (20), and wherein the hydrogen, the methane and the higher hydrocarbons each originate at least in part from the cracked gas (102).

3. A process according to claim 2, wherein the upgrading (20) comprises deethanization and the higher hydrocarbons are more than 90% hydrocarbons having two carbon atoms.

4. The method (100) according to any one of the preceding claims, wherein the first condensation (31) is carried out at a first condensation pressure level of 20 to 45 bar, and wherein the second condensation (34, 33) is carried out at a second condensation pressure level of 20 to 45 bar.

5. The method (100) of claim 4, wherein the second condensation pressure level is equal to or higher than the first condensation pressure level.

6. The method (100) according to any one of the preceding claims, wherein the uncondensed portion (105) of the first condensation insert (103) or the part thereof used to form the pressure swing adsorption insert (112) and the uncondensed portion (111) of the second condensation insert (115) or the part thereof used to form the pressure swing adsorption insert (112) are heated to a temperature level above 0 °C, and wherein the heating is carried out at the first condensation pressure level.

7. The method (100) according to any one of the preceding claims, wherein the condensed portion (104) of the first condensation insert (103) and a portion of the condensed portion (116) of the second condensation insert (116) are subjected to low-temperature rectification (32).

8. The method (100) according to claim 7, wherein a The top gas formed in the low-temperature rectification (32) is cooled with heat transfer to the recycle partial quantity (118) and partially condensed to obtain a condensed and a non-condensed top gas portion, wherein the non-condensed top gas portion or a portion thereof is heated and removed from the process (100) and the condensed top gas portion or a portion thereof is recycled as reflux to the low-temperature rectification (32).

9. Method (100) according to one of the preceding claims, in which - the separating insert (103) has a content of 20 to 60 mol percent hydrogen, 2 to 20 mol percent methane and 40 to 70 mol percent of the higher hydrocarbons and / or - the uncondensed portion (105) of the first condensation feed (103) has a content of 70 to 95 mol percent hydrogen, 5 to 30 mol percent methane and 1 to 20 mol percent of the higher hydrocarbons and / or - the hydrogen fraction (113) has a content of 90 to 100 mol% of hydrogen, 0 to 10 mol% of methane and 0 to 10 mol% of higher hydrocarbons and / or - the pressure swing adsorption residual gas (114) has a content of 20 to 60 mol percent hydrogen, 20 to 60 mol percent methane and 2 to 40 mol percent of the higher hydrocarbons and / or - the uncondensed portion (111) of the second condensation feed (115) has a content of 70 to 95 mol percent hydrogen, 5 to 30 mol percent methane and 1 to 20 mol percent of the higher hydrocarbons and / or - the condensed portion (116) of the second condensation feed (115) has a content of 0 to 10 mol percent of hydrogen, 40 to 99 mol percent of methane and 10 to 60 mol percent of the higher hydrocarbons.

10. Method (100) according to one of the preceding claims, in which a geared turbo compressor or a single-shaft turbo compressor with several compressor stages is used for the compression (37).

11. Plant for providing a hydrogen fraction (113), which has a separation arrangement and is designed to subject a separation insert (103) containing hydrogen, methane and higher hydrocarbons to a separation (30) in the separation arrangement and in the process - subjecting the separating insert (103) as a first condensation insert (103) to a first condensation (31) at a minimum first condensation temperature level of -95 °C to -100 °C, while obtaining a condensed portion (104) and leaving an uncondensed portion (105), - subjecting a second condensation insert (115) to a second condensation (34, 33) at a minimum second condensation temperature level of -130 °C to -150 °C, while obtaining a condensed portion (116) and leaving an uncondensed portion (111), subjecting a pressure swing adsorption insert (112) to a pressure swing adsorption (36) while obtaining the hydrogen fraction (113) and a pressure swing adsorption residual gas (114), - to form the second condensation insert (115) using the pressure swing adsorption residual gas (114) or a part thereof and a recirculation portion (118) of the condensed portion (116) of the second condensation insert (115), - to form the pressure swing adsorption insert (112) using the uncondensed portion (105) of the first condensation insert (103) or a part thereof and the uncondensed portion of the second condensation insert (111) or a part thereof, - the formation of the second condensation insert (115) comprises compressing (37) the pressure swing adsorption residual gas (114) or its portion used to form the second condensation insert (115) and expanding, evaporating and compressing (37) the recirculation portion (118), and - the second condensation (34, 33) comprises a heat transfer from the second condensation insert (115) to the return subset (118).

12. Plant according to claim 11, which is arranged to carry out a method (100) according to one of claims 1 to 10.

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