Process and plant for obtaining a hydrogen stream

By increasing steam generation and utilizing it to produce excess electricity, the method addresses CO2 emissions in hydrogen production, achieving a negative CO2 balance and improved energy efficiency in ammonia production processes.

WO2026131480A1PCT designated stage Publication Date: 2026-06-25GASCONTEC

Patent Information

Authority / Receiving Office
WO · WO
Patent Type
Applications
Current Assignee / Owner
GASCONTEC
Filing Date
2025-12-12
Publication Date
2026-06-25

AI Technical Summary

Technical Problem

Existing hydrogen production methods, such as those using autothermal reformers (ATR), generate significant CO2 emissions, and there is a need to reduce these emissions while ensuring energy self-sufficiency and efficiency in ammonia production processes.

Method used

Modify the fired heater to increase steam generation beyond plant requirements, using the excess steam to generate electricity and export it, thereby improving the CO2 balance by utilizing the additional steam and electricity in other processes.

Benefits of technology

The method achieves a negative CO2 balance by generating more electricity and steam than needed, reducing overall emissions and enhancing energy efficiency in hydrogen production.

✦ Generated by Eureka AI based on patent content.

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Abstract

The invention relates to a process for obtaining a hydrogen stream (1) in a plant (2), wherein a carbon-containing energy carrier stream (3) and an oxygen stream (4) are fed from an oxygen recovery arrangement (5) of the plant (2) to an ATR reactor arrangement (6) of the plant (2) for obtaining a synthesis gas stream (7) comprising hydrogen and carbon oxides, wherein the ATR reactor arrangement (6) affords the synthesis gas stream (7) from the energy carrier stream (3) by autothermal reforming with the oxygen stream (4), so that a catalytic partial oxidation in particular provides the heat required for the endothermic reforming reactions, wherein the synthesis gas stream (7) is fed at least partly to a separating device (8) of the plant (2) for separating the synthesis gas stream (7) into the hydrogen stream (1) including hydrogen and a purge stream (9) including carbon oxides, wherein the plant (2) has a steam heater (13), which steam heater (13) has at least one superheating stage (14a, b) for obtaining a respective superheated output steam stream (15a, b) from a respective input steam stream (16a, b), which input steam stream (16a, b) is conducted through the steam heater (13) until the superheated output steam stream (15a, b) is obtained, and wherein the plant (2) includes a turbine arrangement (12) for generating electrical power, which turbine arrangement (12) is driven by at least one superheated output steam stream (15a, b), characterized in that the at least one superheating stage (14a, b) has at least two heating sections (17) in each case, which heating sections (17) are guided through an inner region (18) of the steam heater (13), in which inner region (18) the heating sections (17) are heated by a burner (19) of the steam heater (13), in that the at least one superheating stage (14a, b) has a quench section (20) which is arranged between the at least two heating sections (17) in terms of process technology, in which quench section (20) steam obtained in
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Description

[0001] Process and plant for generating a hydrogen stream

[0002] The invention relates to a method for obtaining a hydrogen stream with the features of the preamble of claim 1, a method for producing hydrogen with the features of the preamble of claim 18, and a plant for obtaining a hydrogen stream with the features of the preamble of claim 19.

[0003] The need to produce hydrogen with the lowest possible CO2 emissions is constantly increasing. This requirement also applies to the production of various substances that use hydrogen as a starting material, such as ammonia. One well-known method for producing hydrogen involves first converting an energy carrier stream, such as natural gas, into synthesis gas, for example, using an autothermal reformer (ATR). Such synthesis gas contains hydrogen, which can then be separated from it. However, energy is required for various processes in such a plant, and it is crucial to ensure that the provision of this energy generates as little CO2 emissions as possible, or ideally, none at all.

[0004] An ammonia plant operated exclusively with an ATR for synthesis gas production, in which a hydrogen stream is also generated for ammonia synthesis, can be designed to operate energy self-sufficiently, meaning that neither steam nor electricity needs to be imported or exported. If the CO2 separated in this process is stored underground, mineralized, or used for an EOR (Enhanced Oil Recovery) process, residual emissions of less than 0.03 t CO2 per t ammonia or less than 0.2 t CO2 per t hydrogen can be achieved. This is made possible by very high CO2 capture efficiencies (up to greater than 98%), which can also be used for the integrated steam-driven power generation.

[0005] A plant for the production of ammonia, in which the synthesis gas is obtained by an ATR, is disclosed in EP 4 269 332 Al as prior art. Based on such a plant and such a process for obtaining a hydrogen stream, the object of the invention is to further improve the CO2 balance.

[0006] With regard to a process for obtaining hydrogen according to the preamble of claim 1, this problem is solved by the features of the characterizing part of claim 1. With regard to a process for producing hydrogen according to the preamble of claim 18, this problem is solved by the features of the characterizing part of claim 18. With regard to a plant for obtaining hydrogen according to the preamble of claim 19, this problem is solved by the features of the characterizing part of claim 19.

[0007] The invention is based on the understanding that by modifying the fired heater (feedstock heater), the amount of steam generated in the process can be increased far beyond the plant's own requirements. This additional steam can be used to generate further electricity without increasing the already existing residual CO2 emissions. This automatically improves the CO2 balance. In total, it is possible to generate even more steam than needed for the plant's operation, more electricity than needed for the plant's operation, or even both.

[0008] There are several sensible ways to utilize this electricity and the additional steam. For example, this electricity can be used to power the compressors in the plant. It can also be exported, and since it was generated without any CO2 emissions, this results in hydrogen production with a negative CO2 balance. Furthermore, the excess steam generated in this way can be extracted from the plant and used, for instance, in another plant, thus eliminating the need to generate this steam there. In this way, the plant's overall calculated CO2 balance can be further reduced and potentially even brought below zero, provided the CO2 savings from the electricity mix used are taken into account.The respective preferred embodiments of subclaim 8 and subclaim 12 describe a way to increase the available heating power for superheating essentially without increasing CO2 emissions.

[0009] The preferred embodiment of dependent claim 15 provides for the use of the teaching to reduce CO2 emissions for the production of ammonia.

[0010] Further details, features, embodiments, objectives and advantages of the present invention are explained below with reference to the drawing, which merely illustrates exemplary embodiments. The drawing shows

[0011] Fig. 1 schematically shows the flow diagram of a proposed plant for carrying out the proposed method according to a first and a second embodiment.

[0012] Fig. 2 schematically shows a steam heater of the system of Fig. 1 according to the first embodiment and

[0013] Fig. 3 schematically shows a steam heater of the system of Fig. 2 according to the second embodiment.

[0014] The proposed method serves to generate a hydrogen stream 1 in a plant 2, wherein a carbon-containing energy carrier stream 3 and an oxygen stream 4 from an oxygen recovery arrangement 5 of plant 2 are fed to an ATR reactor arrangement 6a of plant 2 to generate a synthesis gas stream 7 containing hydrogen and carbon oxides. The energy carrier stream 3 is preferably a natural gas stream. The illustration in Fig. 1 relates to both the first and second embodiments of the proposed plant. Both are configured to carry out the proposed method.

[0015] In the proposed process, the ATR reactor assembly 6a obtains the synthesis gas stream 7 from the energy carrier stream 3 through autothermal reforming with the oxygen stream 4, such that a partial oxidation, particularly catalytic, provides the heat required for the endothermic reforming reactions. It has been found that a steam-to-carbon ratio of between 1.8 and 2.7 for the energy carrier stream 3 when fed to the ATR reactor assembly 6a is particularly advantageous. This ratio ensures a low methane slip. Methane in the synthesis gas can usually only be removed by circulating the gas, which, however, leads to CO2 emissions. Reducing the methane slip therefore reduces CO2 emissions from this source.

[0016] In the proposed process, the synthesis gas stream 7 is at least partially fed to a separation device 8 of plant 2 for separating the synthesis gas stream 7 into the hydrogen-containing hydrogen stream 1 and a purge stream 9 containing carbon oxides. Preferably, the synthesis gas stream 7 is fed substantially all of the way to the separation device 8. It is also preferred that the synthesis gas stream 7 is fed to a CO2 scrubber 34 of plant 2, which is located upstream of the separation device 8. In this way, the CO2 content of the purge stream 9 can be reduced, which in turn reduces CO2 emissions when the purge stream 9 is combusted. Preferably, plant 2 also includes at least one shift device 6c for a water-gas shift reaction, which is arranged upstream of the CO2 scrubber 34.With such a shift device 6c, CO in the synthesis gas stream 7 can be converted into CO2 before scrubbing. This prevents this CO from entering the purge stream 9 and subsequently contributing to CO2 emissions during combustion.

[0017] In the proposed method, the system 2 includes a steam heater 13. Such a steam heater 13 according to the first embodiment of the proposed method and according to the first embodiment of the proposed system 2 is shown in Fig. 2. A steam heater 13 according to the second embodiment of the proposed method and according to the second embodiment of the proposed system 2 is shown in Fig. 3.

[0018] The proposed method further provides that the steam heater 13 has at least one superheating stage 14a, b for obtaining a respective superheated output steam stream 15a, b from a respective input steam stream 16a, b, wherein the input steam stream 16a, b is passed through the steam heater 13 until the superheated output steam stream 15a, b is obtained. Preferably, the respective input steam stream 16a, b is saturated with steam.

[0019] In the proposed method, the system 2 includes a turbine arrangement 12 for generating electric current, which turbine arrangement 12 is driven by at least one superheated output steam stream 15a, b.

[0020] The proposed method is characterized in that the at least one superheating stage 14a, b each has at least two heating sections 17, which heating sections 17 are guided through an inner area 18 of the steam heater 13, in which inner area 18 the heating sections 17 are heated by a burner 19 of the steam heater.

[0021] The proposed method is characterized in that the at least one superheating stage 14a, b has a quench section 20 arranged between the at least two heating sections 17, in which boiler feedwater 21 generated in the plant is supplied to the incoming steam stream 16a for quenching. Boiler feedwater 21 is essentially any water that includes process condensate generated at any point in the plant and, if applicable, additionally supplied water. For example, the boiler feedwater 21 can be partially obtained from condensate 36 of the turbine assembly 12.

[0022] Such quenching allows the steam content to be further increased, which in turn increases the electricity yield of turbine arrangement 12 in plant 2. This electricity yield can be increased to such an extent that more electricity can be generated than is needed in plant 2. By exporting this electricity, the CO2 balance of plant 2 can even be reduced to below zero.

[0023] According to a preferred embodiment of the proposed method, the electrical current generated by the turbine arrangement 12 is at least partially exported from the system 2. In other words, at least a portion of the generated current is extracted from the system 2 and supplied to an electrical consumer outside the system 2. Such a consumer can also be an electrical energy storage device. In this way, the system 2 functions as a power plant and consequently serves as a source of electrical energy. It is also preferred that, alternatively or additionally, at least one superheated output steam stream 15a, b is at least partially extracted from the system 2. According to this variant, at least one superheated output steam stream 15a, b is thus at least partially exported outside the system 2.This export may consist, for example, of supplying the corresponding part of the at least one superheated output steam stream 15a, b to another plant and specifically to a consumer of steam in this other plant.

[0024] A preferred embodiment of the proposed method is characterized in that the boiler feedwater 21 is diverted downstream of a boiler feedwater pump 21a for quenching. In this way, the boiler feedwater 21 can be supplied at the increased pressure provided by the boiler feedwater pump 21a. Alternatively or additionally, the boiler feedwater 21 can be diverted downstream of a conditioning device 21b of the system 2 for conditioning with a phosphate before being supplied for quenching. Specifically, the conditioning in the conditioning device 21b can be carried out with sodium phosphate.In addition to the conditioning device 21b for conditioning with a phosphate, the system 2 can have further conditioning devices for conditioning the boiler feedwater 21, whereby the branch for the supply to quench can be made at basically any point in the process technology relative to these.

[0025] In principle, the respective incoming steam stream 16a, b can be of any origin. Preferably, the system 2 has a waste heat boiler 6b and the respective incoming steam stream 16a, b is heated in the waste heat boiler 6b. In particular, the waste heat boiler 6b can be located downstream of the ATR reactor arrangement 6a. Alternatively or additionally, the waste heat boiler 6b can be located upstream of the at least one shift device 6c. A preferred embodiment of the proposed method is characterized in that a multiple quench superheating stage 22 of the at least one superheating stage 14a, b has a plurality of quench sections 20, wherein each of the quench sections 20 is arranged between two respective heating sections 17 of the multiple quench superheating stage 22. As shown in the figure.In the first embodiment, the first superheating stage 14a is a multi-quench superheating stage 22. This multi-quench superheating stage 22 has a total of four quench sections 20 and five heating sections 17. In this way, the steam content in the initial steam stream 15a can be increased significantly.

[0026] Another preferred embodiment of the proposed method is characterized in that the steam heater 13 has a plurality of superheating stages 14a, b for obtaining a respective superheated output steam stream 15a, b from a respective input steam stream 16a, b. Both the steam heater 13 of the first embodiment according to Fig. 2 and the steam heater 13 of the second embodiment according to Fig. 3 each have two superheating stages 14a, b.

[0027] According to a preferred embodiment of the proposed method, each of the plurality of superheating stages 14a, b has a respective inlet steam flow 16a, b and a respective outlet steam flow 15a, b with a different steam pressure. It is further preferred that the steam pressure of the inlet steam flow 16a and the outlet steam flow 15a of a first superheating stage 14a of the plurality of superheating stages 14a, b is in a high-pressure range, and that the steam pressure of the inlet steam flow 16a and the outlet steam flow 15a of a second superheating stage 14b of the plurality of superheating stages 14a, b is in a medium-pressure range. This applies to both the first embodiment according to Fig. 2 and the second embodiment according to Fig.3. The inlet steam flow 16a of the first superheating stage 14a is a saturated high-pressure steam flow 23, and the inlet steam flow 16b of the second superheating stage 14b is a saturated medium-pressure steam flow 24. In particular, the high-pressure steam flow 23 has a pressure between 90 bar and 115 bar. Accordingly, the medium-pressure steam flow 24 can have a pressure between 30 bar and 50 bar.

[0028] According to a further preferred embodiment of the proposed method, the superheated output steam stream 15a, b has a mass flow rate of steam which is at least 120% of the mass flow rate of steam of the input steam stream 16a, b.

[0029] According to a preferred embodiment of the proposed method, the steam heater 13 is provided with a heat exchanger 37 for heating an oxygen-containing combustion gas 38 by means of a flue gas 39 as exhaust gas from the burner 19. This is illustrated in Figures 2 and 3. Preferably, the combustion gas 38 is ambient air. The combustion gas 38 is supplied to the burner 19 for its operation and thus feeds the burner 19. The flue gas 39 is produced as exhaust gas by the operation of the burner 19 and then escapes from the steam heater 13. By providing the heat exchanger 37, preheating of the combustion gas 38 is achieved.

[0030] A preferred embodiment of the proposed method is characterized in that the energy carrier flow 3 is supplied to a preheating stage 25 of the plant 2, which is upstream of the ATR reactor arrangement 6, for the preheating of the energy carrier flow 3.

[0031] It is preferred that the preheating stage 25 is supplied predominantly, and preferably exclusively, by the purge stream 9. In other words, the energy for the heat of the preheating stage 25 is obtained predominantly, and preferably exclusively, by combustion of the purge stream 9. It is also possible, as shown in Fig. 1, that the preheating stage 25 is supplied by both the hydrogen stream 1 and the purge stream 9. This variant is shown in Fig. 1. Alternatively, the preheating stage 25 can be supplied by a gas stream that has been diverted from the energy carrier stream 3.

[0032] Another preferred embodiment of the proposed method is characterized in that the separation device 8 is an adsorption device and is operated with an efficiency of approximately 90%, such that approximately 10% of the hydrogen in the synthesis gas stream 7 supplied to the adsorption device enters the purge stream 9. It is also possible for the separation device 8 to be operated with an efficiency between 90% and 70%, such that between 10% and 30% of the hydrogen in the synthesis gas stream 7 supplied to the adsorption device enters the purge stream 9. In this way, it can be ensured that a sufficiently high heating capacity can be provided with the purge stream 9 without increasing the CO2 emissions caused by the combustion of the purge stream. Here, it is further preferred that the adsorption device is a pressure-swing adsorption (PSA) device.

[0033] According to a preferred embodiment of the proposed method, the energy carrier stream 3 is supplied to a saturation stage 26 of the plant 2, which is located upstream of the ATR reactor arrangement 6, for saturation with steam, and the saturation stage 26 is fed with process condensate. In other words, process condensate obtained in the plant 2 provides at least partially, and preferably substantially, the steam for saturating the energy carrier stream 3.

[0034] According to a further preferred embodiment of the proposed method, the boiler feedwater 21 supplied to the inlet steam stream 16a, b in the respective quench section 20 is at least partially obtained from process condensate of the plant 2. Preferably, the supplied boiler feedwater 21 is predominantly obtained from process condensate of the plant 2.

[0035] A preferred embodiment of the proposed method is characterized in that the steam heater 13 has a steam generation stage 27 for generating an additional steam stream 28 heated to at least 290°C. Preferably, the steam generation stage 27 has an additional heating section 29, which is arranged in the interior 18 of the steam heater 13 opposite a heating section 17. This corresponds to the steam heater 13 of the second embodiment shown in Fig. 3. In particular, this steam generation stage 27 can have a steam drum 30 for generating the additional steam stream 28. Preferably, the additional steam stream 28 is fed to an inlet steam stream 16a before it is supplied to the superheating stage 14a. Fig. 3 shows how the additional steam stream is fed to the inlet steam stream 16a before the latter is supplied to the first superheating stage 14a.

[0036] Another preferred embodiment of the proposed method is characterized in that the steam heater 13 and, in particular, the burner 19 of the steam heater 13 is supplied with hydrogen, preferably with hydrogen from the hydrogen stream 1. In this way, the steam heater 13 can be operated without or at least with low CO2 emissions.

[0037] According to a preferred embodiment of the proposed method, the system 2 comprises a compressor arrangement 10 with at least one compressor lla-c. In the present embodiment, the compressor arrangement comprises a total of three compressors lla-c.

[0038] A first compressor 11a serves to increase the pressure of ambient air 35 before it is fed to the oxygen recovery arrangement 5. This is preferably an air separation arrangement. The second compressor 11b is a natural gas compressor for increasing the pressure of the energy carrier stream 3. The third compressor 11c is a purge gas compressor for increasing the pressure of the purge stream 9.

[0039] According to a preferred variant of the proposed method, the compressor arrangement 10 is at least partially operated with steam and the at least one superheated output steam stream 15a, b is supplied to the compressor arrangement 10.

[0040] According to a further preferred embodiment of the proposed method, the compressor arrangement is at least partially powered by electricity, and the electricity for operating the compressor arrangement 10 is generated at least partially, and in particular substantially entirely, by the turbine arrangement 12. Electrically operated compressors regularly require a large proportion of the total electricity consumed by the plant 2. If the steam for operating the turbine arrangement 12 can be generated with the lowest possible CO2 emissions, this significantly improves the overall CO2 balance of the plant 2. It is further preferred that substantially all of the electricity demand of the plant 2 is met by the turbine arrangement 12. In particular, it is even possible that the electrical power generated by the turbine arrangement 12 exceeds the electricity demand of the plant 2.In this way, a positive overall CO2 balance for plant 2 can in principle even be achieved.

[0041] A preferred embodiment of the proposed method is accordingly characterized in that the electricity generated by the turbine arrangement 12 is at least partially supplied by the plant 2. In other words, the plant 2 exports at least a portion of the electricity generated by the turbine arrangement 12. This electricity can, for example, be fed into a conventional power grid or used to operate another plant.

[0042] According to a further preferred embodiment of the proposed method, the system comprises an ammonia reactor arrangement 31, and the hydrogen stream 1 and a nitrogen stream 32 are supplied to the ammonia reactor arrangement 31 for the production of ammonia 33. Preferably, the nitrogen stream 32 is also provided by the oxygen recovery arrangement 5.

[0043] A preferred embodiment of the proposed method is characterized in that the energy carrier stream 3 comprises natural gas. Preferably, the energy carrier stream 3 consists essentially of natural gas.

[0044] The proposed plant 2 serves to generate a hydrogen stream 1 and comprises an oxygen recovery arrangement 5 for providing an oxygen stream 4 and an ATR reactor arrangement 6 for generating a synthesis gas stream 7 containing hydrogen and carbon oxides, wherein a carbon-containing energy carrier stream 3 and the oxygen stream 4 are supplied to the ATR reactor arrangement 6. In the proposed plant 2, the ATR reactor arrangement 6 is configured to generate the synthesis gas stream 7 from the energy carrier stream 3 by means of autothermal reforming with the oxygen stream 4, such that a partial oxidation, in particular catalytic, provides the heat required for the endothermic reforming reactions.

[0045] The proposed system 2 further comprises a separation device 8 for separating the synthesis gas stream 7 into the hydrogen-containing hydrogen stream 1 and into a purge stream 10 containing carbon oxides, to which the synthesis gas stream 7 is at least partially fed by the separation device 8.

[0046] The proposed system 2 also includes a compressor arrangement 10 with at least one compressor lla-c and a steam-driven turbine arrangement 12, which provides electrical current by which the compressor arrangement 10 is at least partially operated.

[0047] The proposed system 2 comprises a steam heater 13, wherein the steam heater 13 has at least one superheating stage 14a, b for obtaining a respective superheated output steam stream 15a, b from a respective input steam stream 16a, b, which input steam stream 16a, b is passed through the steam heater 13 until the superheated output steam stream 15a, b is obtained.

[0048] The proposed system 2 is characterized in that the at least one superheating stage 14a, b each has at least two heating sections 17, which heating sections 17 are guided through an inner area 18 of the steam heater 13, in which inner area 18 the heating sections 17 are heated by a burner 19 of the steam heater 13, wherein the at least one superheating stage 14a, b has a quench section 20 arranged between the at least two heating sections 17, in which quench section 20 steam generated in system 2 is supplied to the inlet steam stream 16a, b for quenching.

[0049] The preferred configurations, features and properties of the proposed method described above correspond to preferred configurations, features and properties of the proposed plant and vice versa.

Claims

Patent claims 1. A process for producing a hydrogen stream (1) in a plant (2), wherein a carbon-containing energy carrier stream (3) and an oxygen stream (4) from an oxygen recovery arrangement (5) of the plant (2) are fed to an ATR reactor arrangement (6) of the plant (2) for producing a synthesis gas stream (7) containing hydrogen and carbon oxides, wherein the ATR reactor arrangement (6) produces the synthesis gas stream (7) from the energy carrier stream (3) by autothermal reforming with the oxygen stream (4), such that a partial oxidation, in particular catalytic, provides the heat required for the endothermic reforming reactions, wherein the synthesis gas stream (7) is fed at least partially to a separation device (8) of the plant (2) for separating the synthesis gas stream (7) into the hydrogen-containing hydrogen stream (1) and into a purge stream (9) containing carbon oxides, wherein the plant (2) comprises a steam heater (13),which steam heater (13) has at least one superheating stage (14a, b) for obtaining a respective superheated output steam stream (15a, b) from a respective input steam stream (16a, b), which input steam stream (16a, b) is passed through the steam heater (13) until the superheated output steam stream (15a, b) is obtained, and wherein the system (2) has a turbine arrangement (12) for generating electric current, which turbine arrangement (12) is driven by at least one superheated output steam stream (15a, b), characterized in that the at least one superheating stage (14a, b) each has at least two heating sections (17), which heating sections (17) are guided through an inner area (18) of the steam heater (13), in which inner area (18) the heating sections (17) are heated by a burner (19) of the Steam heater (13) are heated so that at least one superheating stage (14a,b) has a quench section (20) arranged between the at least two heating sections (17) in which boiler feedwater (21) generated in the plant (2) is supplied to the incoming steam stream (16a, b) for quenching.

2. Method according to claim 1, characterized in that the electric current generated by the turbine arrangement (12) is at least partially exported from the system (2), preferably that at least one superheated output steam stream (15a, b) is at least partially discharged from the system (2).

3. Method according to claim 1 or 2, characterized in that a multiple quench superheating stage (22) of the at least one superheating stage (14a, b) has a plurality of quench sections (20), wherein each of the quench sections (20) is arranged process-wise between two respective heating sections (17) of the multiple quench superheating stage (22).

4. Method according to one of claims 1 to 3, characterized in that the steam heater (13) has a plurality of superheating stages (14a, b) for obtaining a respective superheated output steam stream (15a, b) from a respective input steam stream (16a, b).

5. Method according to claim 4, characterized in that each of the plurality of superheating stages (14a, b) has a respective inlet steam flow (16a, b) and a respective outlet steam flow (15a, b) with a different steam pressure, preferably that the steam pressure of the inlet steam flow (16a) and the outlet steam flow (15b) of a first superheating stage (14a) of the plurality of superheating stages (14a, b) is in a high-pressure range and that the steam pressure of the inlet steam flow (16b) and the outlet steam flow (15b) of a second superheating stage (14b) of the plurality of superheating stages (14a, b) is in a medium-pressure range.

6. Method according to any one of claims 1 to 5, characterized in that the superheated output steam stream (15a, b) has a mass flow rate of steam which is at least 120% of the mass flow rate of steam of the input steam stream (16a, b).

7. Method according to one of claims 1 to 6, characterized in that the energy carrier flow (3) of one of the ATR reactor arrangement (6) The process-technically upstream preheating stage (25) of the plant for preheating the energy carrier stream (3) is supplied, which preheating stage (25) is predominantly, preferably exclusively, supplied with the purge stream (9).

8. Method according to any one of claims 1 to 7, characterized in that the separation device (8) is an adsorption device and that the separation device (8) is operated with an efficiency of about 90%, such that about 10% of the hydrogen in the synthesis gas stream (7) supplied to the adsorption device enters the purge stream (9).

9. Method according to one of claims 1 to 8, characterized in that the energy carrier flow (3) is supplied to a saturation stage (26) of the plant (2) upstream of the ATR reactor (6) for saturation with steam and that the saturation stage (26) is fed with process condensate.

10. Method according to one of claims 1 to 9, characterized in that the boiler feedwater (21) supplied to the inlet steam stream (16a, b) in the respective quench section (20) is preferably obtained substantially entirely from process condensate of the plant (2).

11. Method according to one of claims 1 to 9, characterized in that the steam heater (13) has a steam generation stage (27) for generating an additional steam stream (28) heated to at least 290°C, preferably that the additional steam stream (28) is supplied to an inlet steam stream (16a, b) before being supplied to the superheating stage (14a, b).

12. Method according to one of claims 1 to 11, characterized in that the steam heater (13) is supplied with hydrogen, preferably from the hydrogen stream (1).

13. Method according to one of claims 1 to 12, characterized in that the system (2) comprises a compressor arrangement (10) with at least a compressor (11a-c), preferably that the compressor arrangement (10) is at least partially operated with steam and that at least one superheated output steam stream (15a, b) is supplied to the compressor arrangement (10).

14. according to claim 13, characterized in that the compressor arrangement (10) is at least partially powered by electricity and the electricity for operating the compressor arrangement (10) is generated at least partially, in particular substantially completely, by the turbine arrangement (12), preferably that substantially the entire electricity demand of the plant (2) is generated by the turbine arrangement (12), further in particular that an electrical power generated by the turbine arrangement (12) exceeds the electricity demand of the plant (2).

15. according to one of claims 1 to 14, characterized in that the system (2) has an ammonia reactor arrangement (31) and that the hydrogen stream (1) and a nitrogen stream (32) are supplied to the ammonia reactor arrangement (31) for the production of ammonia (33).

16. Method according to one of claims 1 to 15, characterized in that the energy carrier flow (3) comprises natural gas, preferably consisting substantially of natural gas.

17. Method according to one of claims 1 to 16, characterized in that the steam heater (13) has a heat exchanger (37) for heating an oxygen-containing combustion gas (38) by means of a flue gas (39) as exhaust gas of the burner (19).

18. Method for producing hydrogen, characterized in that the hydrogen is obtained from a hydrogen stream (1) which was obtained according to the method according to one of claims 1 to 17.

19. Plant (2) for obtaining a hydrogen stream (1), comprising an oxygen recovery arrangement (5) for providing an oxygen stream (4), comprising an ATR reactor arrangement (6) for obtaining a synthesis gas stream (7) with hydrogen and carbon oxides, wherein a carbon-containing energy carrier stream (3) and the oxygen stream (4) are supplied to the ATR reactor arrangement (6), wherein the ATR reactor arrangement (6) is configured to obtain the synthesis gas stream (7) from the energy carrier stream (3) by autothermal reforming with the oxygen stream (4), such that a particularly catalytic partial oxidation provides the heat required for the endothermic reforming reactions, and the plant (2) comprising a separation device (8) for separating the synthesis gas stream (7) into the hydrogen-containing hydrogen stream (1) and into a carbon oxide-containing purge stream (10), to which the synthesis gas stream (3) is at least partially supplied, wherein the plant (2) comprises a steam heater (13), wherein the steam heater (13) has at least one superheating stage (14a, b) for obtaining a respective superheated output steam stream (15a, b) from a respective input steam stream (16a,b) has which input steam flow (16a, b) is passed through the steam heater (13) until the superheated output steam flow (15a, b) is obtained, and wherein the system (2) has a turbine arrangement (12) for generating electric current, which turbine arrangement (12) is driven by at least one superheated output steam flow (15a, b), characterized in that the at least one superheating stage (14a, b) each has at least two heating sections (17), which heating sections (17) are guided through an inner area (18) of the steam heater (13), in which inner area (18) the heating sections (17) are heated by a burner (19) of the steam heater (13), wherein the at least one superheating stage (14a, b) has a quench section (20) arranged between the at least two heating sections (17), in which quench section (20) the incoming steam flow (16a,b) boiler feedwater (21) generated in the plant (2) is supplied for quenching.