DE102022213277B3 - Process and system for producing an educt gas mixture containing or consisting of hydrogen and nitrogen - Google Patents

Abstract

A process and a system for producing an educt gas mixture containing or consisting of hydrogen and nitrogen are provided. The process and the system are characterized by the fact that only a maximum of two solid oxide electrolysis cell stacks (solid oxide electrolysis cell stack = SOEC stack) are used, no air is supplied to the first SOEC stack, and one Burner between the two SOEC stacks on the one hand air and on the other hand water vapor is supplied at a temperature in the range of 100 ° C to 150 ° C. With the process and the system it is possible to produce a reactant gas mixture that contains or consists of hydrogen and nitrogen in a small space and in a more energy-efficient and cost-effective manner, while also minimizing the risk of downtime.

Description

A process and a system for producing an educt gas mixture containing or consisting of hydrogen and nitrogen are provided. The process and the system are characterized by the fact that only a maximum of two solid oxide electrolysis cell stacks (solid oxide electrolysis cell stack = SOEC stack) are used, no air is supplied to the first SOEC stack, and one Burner between the two SOEC stacks on the one hand air and on the other hand water vapor is supplied at a temperature in the range of 100 ° C to 150 ° C. With the process and the system it is possible to produce a reactant gas mixture that contains or consists of hydrogen and nitrogen in a small space and in a more energy-efficient and cost-effective manner, while also minimizing the risk of downtime.

For the sustainable, emission-free production of ammonia (NH ₃ ), substitution of the fossil raw material base with renewable energies is essential. With regard to the process-related CO ₂ emissions that cannot be avoided in the conventional Haber-Bosch process, this primarily affects the process stage of educt gas production. Within this, a gas mixture of hydrogen (H ₂ ) and nitrogen (N ₂ ) is generated, which is converted into NH ₃ in the downstream synthesis. The use of renewable energy, realized through the integration of electrolysis into the synthesis process, results in profound changes to the process chain, as conventional processes for producing educt gas are no longer applicable.

In principle, both low-temperature processes and high-temperature electrolysis can be used to integrate renewable energy using electrolysis. Depending on the process management, an additional process stage for providing N ₂ may be necessary.

A solution known in the prior art for electrolyte-based educt gas production is based on a separate production of H ₂ from H ₂ O and N ₂ from air with subsequent merging and reaction of the material streams to form NH ₃ . The processes of alkaline electrolysis, PEM electrolysis and high-temperature electrolysis can be used for H ₂ O electrolysis. N ₂ is obtained directly from the air in air separation using low-temperature rectification (cryogenic air separation unit = ASU), pressure swing adsorption (PSA) or membrane technology. Due to the high purity of the gases produced by electrolysis or air separation, the subsequent cleaning of the educt gas is limited to the removal of unreacted H ₂ O. Furthermore, a very low proportion of inert gas results in the downstream synthesis cycle. Educt gas production designed in this way can be operated entirely with electrical energy. If this is obtained from renewable sources, emission-free NH ₃ production can be achieved. A simplified flow diagram of this known process is in 1 shown.

Another method for electrolysis-based educt gas production is known in the prior art. This is based on a series connection or cascade of at least two SOEC stacks with intermediate air supply (see WO 2019/ 072 608 A1 ). This process requires the use of high-temperature electrolysis in at least two, especially eight, SOEC stacks. The advantage of this process is that, unlike the previously described process, there is no need for separate air separation. However, this method has the first disadvantage that it requires more than two (especially 8) SOEC stacks for a sufficiently high nitrogen input. Furthermore, in an endothermic electrolysis operation, as provided for in the process, a large cell area is required, ie the use of materials is very high and high investment costs are incurred. In addition, in this process, the first SOEC stack is supplied with a mixture that contains both water vapor and air, which increases the energy consumption of the process. Apart from that, during high-temperature electrolysis, the SOEC stacks must be brought to and maintained at a very high temperature, which, with a large number of stacks, entails a high heat input and, due to a high temperature gradient to the environment, high heat losses during the implementation of the process. The implementation of the process could therefore be energy-saving and cost-effective (ie more economical and ecological).

The DE 10 2016 213 360 A1 discloses a method and a system for producing ammonia by electrolysis using at least one electrolysis cell, wherein a) nitrogen is fed into the electrolysis cell as the first educt and b) water in the form of water vapor is used as the second educt for the electrolysis, the extraction the educts of the ammonia electrolysis are connected upstream.

The EP 0 058 784 A1 discloses a method and a system for producing nitrogen oxide (NO) by combining H ₂ O vapor electrolysis (cathode side) with NH ₃ oxidation (anode side) in a combined high-temperature electrolysis cell, which is used together with a Haber-Bosch NH ₃ -Synthesis apparatus forms an integrated overall system, with a cathode-side fall hydrogen is used together with atmospheric nitrogen for NH ₃ synthesis and oxygen occurring on the anode side is used for NH ₃ oxidation.

Based on this, the object of the present invention was to provide a process and a system for producing hydrogen (H ₂ ) and nitrogen (N ₂ ) which do not have the disadvantages of the prior art. In particular, the process and the system should allow H ₂ and N ₂ to be produced in a more energy-efficient and cost-effective manner (ie more ecological and economical).

The task is solved by the method with the features of claim 1 and the system with the features of claim 10. The dependent claims show advantageous developments.

1. a) Einleiten von einem Gas, das Wasserdampf, aber keine Luft, enthält oder daraus besteht, in eine Kathode eines ersten SOEC-Stacks, der eine Anode und eine Kathode aufweist, wobei in dem ersten SOEC-Stack aus dem Wasserdampf teilweise Sauerstoff und Wasserstoff hergestellt wird und Sauerstoff und Wasserstoff räumlich getrennt werden, wobei mindestens 20 Vol.-% des Wasserdampfs, in Bezug auf ein Gesamtvolumen des Wasserdampfs, nicht zu Sauerstoff und Wasserstoff umgesetzt werden;
2. b) Ausleiten des Sauerstoffs aus der Anode des ersten SOEC-Stacks als Abgas;
3. c) Ausleiten eines Gemischs, das Wasserstoff und nicht umgesetzten Wasserdampf enthält oder daraus besteht, aus der Kathode des ersten SOEC-Stacks in einen Brenner, wobei in den Brenner zusätzlich Luft und zusätzlich Wasserdampf eingeleitet wird, wobei der zusätzlich eingeleitete Wasserdampf eine Temperatur im Bereich von 100 °C bis 150 °C aufweist, wobei in dem Brenner aus dem Gemisch, der zusätzlich eingeleiteten Luft und dem zusätzlich eingeleiteten Wasserdampf ein Gas entsteht, das Wasserdampf, Stickstoff und mindestens 5 Vol.-% Wasserstoff, in Bezug auf das Gesamtvolumen des Gases, enthält oder daraus besteht;
4. d) Einleiten des Gases aus dem Brenner in eine Kathode eines zweiten SOEC-Stacks, der eine Anode und eine Kathode aufweist, wobei in dem zweiten SOEC-Stack aus dem Wasserdampf des Gases Sauerstoff und Wasserstoff hergestellt wird und Sauerstoff und Wasserstoff räumlich getrennt werden, wobei mindestens 20 Vol.-% des Wasserdampfs, in Bezug auf ein Gesamtvolumen des Wasserdampfs, nicht zu Sauerstoff und Wasserstoff umgesetzt werden;
5. e) Ausleiten von Sauerstoff aus der Anode des zweiten SOEC-Stacks als Abgas; und
6. f) Ausleiten eines Gemischs, das Wasserstoff, Stickstoff und nicht umgesetzten Wasserdampf enthält oder daraus besteht, aus der Kathode des zweiten SOEC-Stacks in eine Kühlvorrichtung, wobei in der Kühlvorrichtung der nicht umgesetzte Wasserdampf zu Wasser kondensiert und das kondensierte Wasser vom Gemisch abgetrennt wird, wobei ein Eduktgasgemisch enthaltend oder bestehend aus Wasserstoff und Stickstoff entsteht;

wobei in dem Verfahren nicht mehr als zwei SOEC-Stacks eingesetzt werden.According to the invention, a process for producing an educt gas mixture containing or consisting of hydrogen and nitrogen is provided, comprising the following steps:

1. a) Introducing a gas that contains or consists of water vapor, but no air, into a cathode of a first SOEC stack, which has an anode and a cathode, the water vapor in the first SOEC stack being partly oxygen and hydrogen is produced and oxygen and hydrogen are spatially separated, with at least 20% by volume of the water vapor, based on a total volume of the water vapor, not being converted into oxygen and hydrogen;
2. b) removing the oxygen from the anode of the first SOEC stack as exhaust gas;
3. c) Discharging a mixture that contains or consists of hydrogen and unreacted water vapor from the cathode of the first SOEC stack into a burner, with additional air and additional water vapor being introduced into the burner, the additionally introduced water vapor having a temperature in the range from 100 ° C to 150 ° C, a gas being formed in the burner from the mixture, the additionally introduced air and the additionally introduced water vapor, which contains water vapor, nitrogen and at least 5% by volume of hydrogen, in relation to the total volume of the gas, contains or consists of;
4. d) introducing the gas from the burner into a cathode of a second SOEC stack, which has an anode and a cathode, oxygen and hydrogen being produced in the second SOEC stack from the water vapor of the gas and oxygen and hydrogen being spatially separated, wherein at least 20% by volume of the water vapor, based on a total volume of the water vapor, is not converted to oxygen and hydrogen;
5. e) discharging oxygen from the anode of the second SOEC stack as exhaust gas; and
6. f) Discharging a mixture containing or consisting of hydrogen, nitrogen and unreacted water vapor from the cathode of the second SOEC stack into a cooling device, the unreacted water vapor condensing into water in the cooling device and the condensed water being separated from the mixture , whereby an educt gas mixture containing or consisting of hydrogen and nitrogen is formed;

whereby no more than two SOEC stacks are used in the process.

The term “SOEC stack” refers to a stack of solid oxide electrolytic cells, i.e. a solid oxide electrolytic cell stack.

In the method according to the invention, only two SOEC stacks are used, which makes it possible to produce an approximately stoichiometric educt gas mixture in only a two-stage arrangement, i.e. with a low system complexity and the smallest possible cell area.

A first essential feature of the method is that the first SOEC stack is supplied with a gas that contains or consists of water vapor, but not air. This reduces the proportion that has to be recycled from the reactant gas that has already been produced to a technically necessary minimum, which is advantageous both in terms of energy and in terms of the dimensioning of the components. In the method according to the invention, nitrogen is therefore only integrated after the first SOEC stack (i.e. between the two SOEC stacks in a burner) by supplying air.

A second essential feature of the method is that, in addition to air, water vapor, which has a temperature in the range from 100 ° C to 150 ° C, is introduced into the burner, which is arranged between the first and second SOEC stack. With this additional water vapor, it is possible to efficiently cool (ie "quench") the gas mixture created in the burner, which has a very high temperature due to the combustion of hydrogen with the oxygen from the air, and at the same time to heat the supplied water vapor, so that the resulting Gas mixture to an ideal working temperature for the second SOEC stack (ie a temperature of 700 °C to 900 °C) is conditioned.

Firstly, this measure allows the first SOEC stack and/or second SOEC stack to be operated exothermically. The advantage here is that the first and second SOEC stacks for electrolysis have a significantly smaller cell area than with processes from the prior art (e.g. the process of WO 2019/ 072 608 A1 ), which significantly reduces process costs and minimizes downtime.

Secondly, this measure allows a gas mixture with a high nitrogen content to be produced upstream of the second SOEC stack, since the cooling effect of the steam introduced into the burner allows more air to be introduced into the burner located upstream of the second SOEC stack than in known burners Process from the prior art. The reason for this is that when hydrogen is burned through a large amount of air (or the oxygen portion of the air), a large amount of heat energy is created, but this heat energy is absorbed by the water vapor, which is also introduced into the burner and has an inlet temperature in the range of 100 to 150 ° C, so that even with a very large air supply (and thus nitrogen supply), the gas can be tempered to an optimal operating temperature of the second SOEC stack.

In known processes from the prior art (e.g. the process of WO 2019/ 072 608 A1 ), a comparable amount of air (and nitrogen) supplied upstream of the second SOEC stack would cause the temperature of the gas to rise too much, i.e. increase to a temperature that is significantly higher than the permissible inlet temperature of the second SOEC stack (T » 900 °C). For example, in order to achieve a comparably high input of nitrogen via air in the process from the WO 2019/ 072 608 A1 To allow this, significantly more than two (e.g. eight) SOEC stacks connected in series would have to be used and the air would have to be supplied (in stages) between these respective stacks. However, this requires more space to carry out the process and makes the process more energy-intensive, costly and error-prone.

It is therefore possible with the method according to the invention to produce an educt gas mixture containing or consisting of hydrogen and nitrogen in a compact space in a more energy-saving, cost-effective and less error-prone manner (ie more economical and ecological). The process is suitable as a starting process for the sustainable production of ammonia (NH ₃ ). Ammonia is currently one of the most important bulk chemicals and will continue to play an important role in the future as a raw material for the chemical industry and fertilizer production as well as as a carbon-free energy source.

The gas introduced into the cathode of the first SOEC stack may have a temperature of ≥800 °C.

In order to produce an educt gas mixture with an H ₂ /N ₂ ratio of approximately 3, the material flow of the gas that is introduced into the cathode of the first SOEC stack can amount to approximately 17.5% of the material flow of a educt gas mixture that is with should be provided (or is provided) for the process (standardized material flow).

Apart from this, the gas that is introduced into the cathode of the first SOEC stack can be introduced into the cathode of the first SOEC stack via a first countercurrent heat exchanger, preferably also via a second countercurrent heat exchanger, particularly preferably also via a first heating device, whereby Gas is heated in the first countercurrent heat exchanger, the second countercurrent heat exchanger and / or the first heating device, preferably to a temperature of at least 800 ° C. The advantage here is that the process is more energy efficient because the heat generated in the process can be used to preheat the gas.

The first SOEC stack and/or the second SOEC stack can have a temperature of 700°C to 900°C, preferably 750°C to 850°C, in particular 800°C. A temperature in this range is advantageous for the partial production of oxygen and hydrogen from the water vapor and to prevent at least 20% by volume of the water vapor from being converted into oxygen and hydrogen.

The oxygen can be discharged from the anode of the first SOEC stack and/or from the anode of the second SOEC stack as exhaust gas via a second countercurrent heat exchanger, optionally also via a third countercurrent heat exchanger, with the oxygen in the second and/or third Countercurrent heat exchanger is cooled, the countercurrent heat exchangers preferably each having a degree of 100 ° C. The advantage here is that the waste heat from the oxygen can be used to preheat the gas that is introduced into the cathode of the first SOEC stack and/or can be used to preheat the additional water vapor that is additionally introduced into the burner.

In the process, the mixture, which contains or consists of hydrogen and unreacted water vapor, can be fed to the burner at a temperature of 700 to 900 ° C, preferably 750 ° C to 850 ° C, in particular 800 ° C.

Furthermore, the burner can be supplied with additional air at a temperature of 20 °C to 30 °C.

In order to produce an educt gas mixture with an H ₂ /N ₂ ratio of approximately 3, the material flow of the additional air can amount to approximately 33% of the material flow of the educt gas mixture that is to be provided (or is provided) by the process (standardized material flow ).

In order to produce an educt gas mixture with an H ₂ /N ₂ ratio of approximately 3, the material flow of the additional water vapor can amount to approximately 83% of the material flow of the educt gas mixture that is to be provided (or is provided) by the process (normalized material flow ).

In addition, the additional water vapor (which has a temperature in the range from 100 ° C to 150 ° C) can be supplied to the burner via a fourth countercurrent heat exchanger, particularly preferably also a third countercurrent heat exchanger, in particular also via a second heating device, the additional water vapor is heated in the fourth countercurrent heat exchanger, the third countercurrent heat exchanger and / or the second heating device, particularly preferably from a temperature of 100 ° C to a temperature in the range of >100 ° C to 150 ° C. The advantage is that the process is more energy efficient because the heat generated in the process can be used to preheat the additional steam.

The gas from the burner, which is introduced into the cathode of the second SOEC stack, can have a temperature in the range from 700 to 900 °C, preferably 750 °C to 850 °C, in particular 800 °C.

The removal of the mixture, which contains or consists of hydrogen, nitrogen and at least 20% by volume of water vapor, based on the total volume of the gas, from the cathode of the second SOEC stack, can be done via a first countercurrent heat exchanger, optionally also via a fourth Countercurrent heat exchanger, the mixture being cooled in the first and/or fourth countercurrent heat exchanger, the countercurrent heat exchangers preferably each having a degree of 100 ° C. The advantage is that the waste heat from the mixture can be used to preheat the water vapor and/or the additional water vapor.

A portion of the mixture discharged from the cathode of the second SOEC stack (in particular its proportion of hydrogen and nitrogen) can be introduced back into the cathode of the first SOEC stack, preferably via a first countercurrent heat exchanger, particularly preferably also via a second countercurrent heat exchanger particularly preferably also via a first heating device, wherein the mixture is heated in the first countercurrent heat exchanger, the second countercurrent heat exchanger and / or the first heating device, preferably to a temperature of at least 800 ° C. This procedure ensures a reducing atmosphere at the inlet of the first SOEC stack, which may be technically necessary to prevent oxidation of the first SOEC stack. Without recirculation, additional provision of hydrogen may be necessary.

In the process, a mixture of hydrogen, nitrogen and ammonia, which was discharged from a Haber-Bosch cycle, can be fed to the anode of the first SOEC stack, preferably via a third heating device, the mixture of hydrogen, nitrogen and ammonia being in the third heating device is heated, preferably to a temperature of ≥ 750 ° C. The chemically bound energy of the purge current of the Haber-Bosch cycle is converted into thermal energy within the first SOEC stack. In addition, anode depolarization occurs, which increases the electrical efficiency of electrolysis. These effects are beneficial for the efficiency of the process. Furthermore, the anode of the first SOEC stack is rinsed and the resulting oxygen is removed, which increases the service life of the first SOEC stack.

Furthermore, in the process, a mixture of hydrogen, nitrogen and ammonia, which was discharged from a Haber-Bosch cycle, can be fed to the anode of the second SOEC stack, preferably via a fourth heating device, the mixture of hydrogen, nitrogen and ammonia is heated in the fourth heating device, preferably to a temperature of ≥ 750 ° C. The chemically bound energy of the purge current of the Haber-Bosch cycle is converted into thermal energy within the second SOEC stack. In addition, anode depolarization occurs, which increases the electrical efficiency of electrolysis. These effects are beneficial for the efficiency of the process. Furthermore, the anode of the second SOEC stack is rinsed and the resulting oxygen is removed, which increases the service life of the second SOEC stack.

In order to produce an educt gas mixture with an H ₂ /N ₂ ratio of approximately 3, the material flow of the mixture of hydrogen, nitrogen and ammonia can amount to approximately 5.5% of the material flow of the educt gas mixture that is to be provided by the process (or . is provided) (standardized material flow). The material flow of the exhaust gas (oxygen) can be approx. 47% of the material flow of the educt gas mixture that is to be provided (or is provided) by the process (standardized material flow) and the material flow of water (which emerges from the cooling device) can be approx 26.5% of the material flow of the educt gas mixture that is to be provided (or is provided) by the process (standardized material flow).

1. a) einen ersten SOEC-Stack, der eine Anode und eine Kathode aufweist und konfiguriert ist, aus Wasserdampf teilweise Sauerstoff und Wasserstoff herzustellen und dabei räumlich zu trennen und mindestens 20 Vol.-% des Wasserdampfs, in Bezug auf ein Gesamtvolumen des Wasserdampfs, nicht zu Sauerstoff und Wasserstoff umzusetzen;
2. b) einen Brenner, der konfiguriert ist, aus einem Gemisch, das aus dem ersten SOEC-Stack ausgeleitet wird sowie zusätzlicher Luft und zusätzlichem Wasserdampf ein Gas herzustellen, das Wasserdampf, Stickstoff und mindestens 5 Vol.-% Wasserstoff, in Bezug auf das Gesamtvolumen des Gases, enthält oder daraus besteht;
3. c) einen zweiten SOEC-Stack, der eine Anode und eine Kathode aufweist und konfiguriert ist, aus Wasserdampf teilweise Sauerstoff und Wasserstoff herzustellen und dabei räumlich zu trennen und mindestens 20 Vol.-% des Wasserdampfs, in Bezug auf ein Gesamtvolumen des Wasserdampfs, nicht zu Sauerstoff und Wasserstoff umzusetzen;
4. d) eine Kühlvorrichtung, die konfiguriert ist, aus einem Gemisch, das aus dem zweiten SOEC-Stack ausgeleitet wird, Wasser aus zu kondensieren und ein Eduktgas herzustellen, das Wasserstoff und Stickstoff enthält oder daraus besteht;

wobei die Anlage nicht mehr als zwei SOEC-Stacks enthält,
wobei die Anlage konfiguriert ist,
ein Gas, das Wasserdampf, aber keine Luft, enthält oder daraus besteht, in die Kathode des ersten SOEC-Stacks einzuleiten,
Sauerstoff aus der Anode des ersten SOEC-Stacks als Abgas auszuleiten;
ein Gemisch, das Wasserstoff und (nicht umgesetzten) Wasserdampf enthält oder daraus besteht, aus der Kathode des ersten SOEC-Stacks in den Brenner zu leiten und zusätzlich Luft und zusätzlich Wasserdampf in den Brenner zu leiten, wobei der zusätzliche Wasserdampf eine Temperatur im Bereich von 100 °C bis 150 °C aufweist,
ein Gas aus dem Brenner in den zweiten SOEC-Stack zu leiten,
Sauerstoff aus der Anode des zweiten SOEC-Stacks als Abgas auszuleiten; und ein Gemisch, das Wasserstoff, Stickstoff und (nicht umgesetzten) Wasserdampf enthält oder daraus besteht, aus der Kathode des zweiten SOEC-Stacks in die Kühlvorrichtung zu leiten.According to the invention, a system for producing an educt gas mixture containing or consisting of hydrogen and nitrogen is also provided

1. a) a first SOEC stack that has an anode and a cathode and is configured to partially produce oxygen and hydrogen from water vapor while spatially separating them and at least 20% by volume of the water vapor, in relation to a total volume of the water vapor convert to oxygen and hydrogen;
2. b) a burner configured to produce a gas comprising water vapor, nitrogen and at least 5% by volume of hydrogen, based on the total volume, from a mixture discharged from the first SOEC stack and additional air and additional water vapor of the gas, contains or consists of;
3. c) a second SOEC stack that has an anode and a cathode and is configured to partially produce oxygen and hydrogen from water vapor while spatially separating them and at least 20% by volume of the water vapor, based on a total volume of the water vapor convert to oxygen and hydrogen;
4. d) a cooling device configured to condense water from a mixture discharged from the second SOEC stack and produce a reactant gas containing or consisting of hydrogen and nitrogen;

whereby the system contains no more than two SOEC stacks,
where the system is configured,
to introduce a gas that contains or consists of water vapor, but not air, into the cathode of the first SOEC stack,
Expelling oxygen from the anode of the first SOEC stack as exhaust gas;
a mixture containing or consisting of hydrogen and (unreacted) water vapor from the cathode of the first SOEC stack into the burner and additional air and additional water vapor into the burner, the additional water vapor having a temperature in the range of 100 °C to 150 °C,
to direct a gas from the burner into the second SOEC stack,
Expelling oxygen from the anode of the second SOEC stack as exhaust gas; and directing a mixture containing or consisting of hydrogen, nitrogen and (unreacted) water vapor from the cathode of the second SOEC stack into the cooling device.

The system has the advantage that it can be used to produce an educt gas mixture containing or consisting of hydrogen and nitrogen in a compact space (i.e. in a compact design) in a more energy-saving, cost-effective and less error-prone manner (i.e. more economical and ecological).

The system can be configured via a control unit of the system,
to introduce the gas, which contains or consists of water vapor but no air, into the cathode of the first SOEC stack,
Expelling oxygen from the anode of the first SOEC stack as exhaust gas;
the mixture containing or consisting of hydrogen and (unreacted) water vapor from the cathode of the first SOEC stack into the burner and additional air and additional water vapor into the burner, the additional water vapor having a temperature in the range of 100 °C to 150 °C,
to direct the gas from the burner into the second SOEC stack,
Expelling oxygen from the anode of the second SOEC stack as exhaust gas; and directing the mixture containing or consisting of hydrogen, nitrogen and (unreacted) water vapor from the cathode of the second SOEC stack into the cooling device.

In a preferred embodiment, the system is configured (optionally controlled via a control unit of the system) to operate the first SOEC stack and/or second SOEC stack exothermically.

The system can be configured to introduce the gas, which contains or consists of water vapor but not air, into the cathode of the first SOEC stack at a temperature of ≥800 °C. The gas may have arisen from a mixture of water and water vapor that is so strong was heated so that the water contained in it had completely evaporated into water vapor.

Furthermore, the system can be configured to introduce the gas, which contains or consists of water vapor but no air, into the cathode of the first SOEC stack with a material stream which is approximately 17.5% of the material flow of an educt gas mixture, which is with should be provided (or is provided) for the system.

In addition, the system can be configured to transfer the gas, which contains or consists of water vapor but no air, into the cathode of the first SOEC via a first countercurrent heat exchanger, preferably also via a second countercurrent heat exchanger, particularly preferably also via a first heating device -Initiate stacks, wherein the first countercurrent heat exchanger, the second countercurrent heat exchanger and / or the first heating device are configured to heat the gas, preferably to a temperature of at least 800 ° C.

The first SOEC stack and/or the second SOEC stack of the system can be configured to have a temperature of 700 °C to 900 °C, preferably 750 °C to 850 °C, in particular 800 °C.

The system can be configured to discharge the oxygen from the anode of the first SOEC stack and/or from the anode of the second SOEC stack as exhaust gas via a second countercurrent heat exchanger, optionally also via the third countercurrent heat exchanger, of the system, the second countercurrent heat exchanger and / or third countercurrent heat exchanger is configured to cool the oxygen, the countercurrent heat exchangers preferably each having a degree of 100 ° C.

The system can be configured to supply the burner with the mixture from the first SOEC stack at a temperature of 700 to 900 °C, preferably 750 °C to 850 °C, in particular 800 °C.

Furthermore, the system can be configured to supply the burner with additional air at a temperature of 20 °C to 30 °C.

Apart from this, the system can be configured to supply the burner with the additional air with a material flow that is approximately 33% of the material flow of a reactant gas mixture that is to be provided (or is provided) with the system.

In addition, the system can be configured to supply the burner with the additional water vapor (i.e. the water vapor that has a temperature in the range from 100 ° C to 150 ° C) with a material flow that is approximately 83% of the material flow of a reactant gas mixture should be provided (or is provided) with the system.

In addition, the system can be configured to supply the burner with the additional water vapor (i.e. the water vapor that has a temperature in the range from 100 ° C to 150 ° C) via a fourth countercurrent heat exchanger, particularly preferably also via a third countercurrent heat exchanger, in particular also via a second heating device, to supply the system, wherein the fourth countercurrent heat exchanger, the third countercurrent heat exchanger and / or the second heating device are configured to heat a mixture containing water and water vapor so that water contained in the mixture completely evaporates to water vapor, particularly preferably to a temperature of >100 °C to 150 °C.

The system can be configured to introduce the gas from the burner into the cathode of the second SOEC stack at a temperature in the range from 700 to 900 °C, preferably 750 °C to 850 °C, in particular 800 °C.

Furthermore, the system can be configured to discharge the mixture, which contains or consists of hydrogen, nitrogen and water vapor, from the cathode of the second SOEC stack via a first countercurrent heat exchanger, optionally also via a fourth countercurrent heat exchanger, of the system, wherein the first countercurrent heat exchanger and / or fourth countercurrent heat exchangers are preferably configured to cool the mixture, the countercurrent heat exchangers preferably each having a degree of 100 ° C.

Apart from this, the system can be configured to direct part of the hydrogen and nitrogen discharged from the cathode of the second SOEC stack back into the cathode of the first SOEC stack, preferably via a first countercurrent heat exchanger, particularly preferably also via a second countercurrent heat exchanger particularly preferably also via a first heating device, the system, wherein the first countercurrent heat exchanger, the second countercurrent heat exchanger and / or the first heating device are configured to heat the hydrogen and nitrogen, preferably to a temperature of at least 800 ° C.

The system can be configured to supply a mixture of hydrogen, nitrogen and ammonia, which was discharged from a Haber-Bosch cycle, to the anode of the first SOEC stack, preferably via a third heating device tion of the system, wherein the third heating device is configured to heat the mixture of hydrogen, nitrogen and ammonia, preferably to a temperature of ≥ 750 ° C.

Furthermore, the system can be configured to supply a mixture of hydrogen, nitrogen and ammonia, which was discharged from a Haber-Bosch cycle, to the anode of the second SOEC stack, preferably via a fourth heating device of the system, the fourth heating device of the system is configured to heat the mixture of hydrogen, nitrogen and ammonia, preferably to a temperature of ≥ 750 ° C.

The system is in particular configured to carry out the method according to the invention.

• 1 zeigt ein Fließschema eines im Stand der Technik bekannten Verfahrens zur elektrolysebasierten Eduktgaserzeugung und Eduktgasreinigung mit getrennter Bereitstellung von H₂ und N₂ zur nachgelagerten Synthese von NH₃. Die nachgelagerte Synthese von NH₃ ist nicht mehr dargestellt.
• 2 zeigt ein Fließbild eines erfindungsgemäßen Verfahrens zur Herstellung eines Eduktgasgemisches enthaltend oder bestehend aus Wasserstoff und Stickstoff. Es wird ein Gas, das Wasserdampf 1, aber keine Luft, enthält oder daraus besteht, in eine Kathode eines ersten SOEC-Stacks 2, der eine Anode und eine Kathode aufweist, eingeleitet, wobei in dem ersten SOEC-Stack 2 aus dem Wasserdampf 1 teilweise Sauerstoff und Wasserstoff hergestellt wird und Sauerstoff und Wasserstoff räumlich getrennt werden, wobei mindestens 20 Vol.-% des Wasserdampfes, in Bezug auf ein Gesamtvolumen des Wasserdampfs, nicht zu Sauerstoff und Wasserstoff umgesetzt werden. Aus der Anode des ersten SOEC-Stacks 2 wird Sauerstoff 3 als Abgas ausgeleitet. Ein Gemisch 4 enthaltend oder bestehend aus Wasserstoff und nicht umgesetzten Wasserdampf wird aus der Kathode des ersten SOEC-Stacks 2 in einen Brenner 5 eingeleitet, wobei in den Brenner 5 zusätzlich Luft 6 und zusätzlicher Wasserdampf 7 eingeleitet wird, wobei der zusätzliche Wasserdampf 7 eine Temperatur im Bereich von 100 °C bis 150 °C aufweist. In dem Brenner 5 entsteht aus dem Gemisch 4, der Luft 6 und dem zusätzlichen Wasserdampf 7 ein Gas 8, das Wasserdampf, Stickstoff und mindestens 5 Vol.-% Wasserstoff, in Bezug auf das Gesamtvolumen des Gases, enthält oder daraus besteht. Dieses Gas 8 wird aus dem Brenner 5 in eine Kathode eines zweiten SOEC-Stacks 9 eingeleitet, der eine Anode und eine Kathode aufweist, wobei in dem zweiten SOEC-Stack 9 aus dem Wasserdampf des Gases 8 Sauerstoff und Wasserstoff hergestellt wird und Sauerstoff und Wasserstoff räumlich getrennt werden. Der Sauerstoff 10 wird als Abgas aus der Anode des zweiten SOEC-Stacks 9 ausgeleitet und ein Gemisch 11, das Wasserstoff, Stickstoff und nicht umgesetzten Wasserdampf enthält oder daraus besteht, wird aus der Kathode des zweiten SOEC-Stacks 9 ausgeleitet. Das Gemisch 11 wird in eine Kühlvorrichtung 20 eingeleitet, wobei in der Kühlvorrichtung 20 Wasserdampf zu Wasser kondensiert und das kondensierte Wasser vom Gemisch abgetrennt wird, wobei ein Eduktgasgemisches enthaltend oder bestehend aus Wasserstoff und Stickstoff entsteht. In dem Verfahren werden nicht mehr als der erste SOEC-Stack 2 und der zweite SOEC-Stack 9 eingesetzt. In der 2 ist ebenfalls die Anordnung und Verwendung des ersten Gegenstromwärmetauschers 12, des zweiten Gegenstromwärmetauschers 13, des dritten Gegenstromwärmetausches 14 und des vierten Gegenstromwärmetauscher 15 illustriert. Ferner ist die Anordnung und Verwendung der ersten Heizvorrichtung 16, der zweiten Heizvorrichtung 17, der dritten Heizvorrichtung 18 und der vierten Heizvorrichtung 19 dargestellt. Abgesehen davon ist die optionale Ausführungsform ersichtlich, bei der ein Gemisch 21 aus Wasserstoff, Stickstoff und Ammoniak, das aus einem Haber-Bosch-Kreisprozess ausgeschleußt wurde, der Anode des ersten SOEC-Stacks 2 über die dritte Heizvorrichtung 18 zugeführt wird und der Anode des zweiten SEOC-Stacks 9 über eine vierte Heizvorrichtung 19 zugeführt wird.
• 3 zeigt einen auf einer Evaluation beruhenden Vergleich des spezifischen Energiebedarfs (ε), der Investitionskosten (TCI) sowie der Produktionskosten (TPC) zwischen dem erfindungsgemäßen Verfahrens, das nur mit zwei SOEC-Stacks auskommt, und einem bekannten Verfahren aus dem Stand der Technik, das acht SOEC-Stacks einsetzt (siehe WO 2019/ 072 608 A1 ) für den Fall einer Produktion von einer Menge an Wasserstoff und Stickstoff, die eine Produktionskapazität von 1000 tNH₃/Tag erlauben. Die Evaluation umfasste sowohl eine Prozesssimulation als auch eine Wirtschaftlichkeitsrechnung für ein sog. „2050 Szenario“. Die zur Wirtschaftlichkeitsbetrachtung angewandte Methodik ist ausführlich beschrieben in HERZ, Gregor [et al.]: Economic assessment of Power-to-Liquid processes - Influence of electrolysis technology and operating conditions. In: Applied Energy, Vol. 292, 2021, Artikelnummer: 116655 (18 S.) . - ISSN 0306-2619 (p); 1872-9118 (e). DOI: 10.1016/j.apenergy.2011.116655 und JACOBASCH, Eric [et al.]: Economic evaluation of low-carbon steelmaking via coupling of electrolysis and direct reduction. In: Journal of Cleaner Production, Vol. 328, 2021, Artikelnummer: 129502 (21 S.). - ISSN 0959-6526 (p); 1879-1786 (e). DOI: 10.1016/j.jclepro.2021.129502 und wurde für das erfindungsgemäße Verfahren und das im Stand der Technik bekannte Verfahren in identischer Weise durchgeführt. Eine ausschließliche Betrachtung der Eduktgaserzeugung war an dieser Stelle nicht zielführend, da insbesondere die Wärmeintegration zwischen Ammoniaksynthese und Eduktgaserzeugung bedeutend sind für die Energieeffizienz und die Wirtschaftlichkeit des Verfahrens. Es wird aus dieser Figur ersichtlich, dass das erfindungsgemäße Verfahren insbesondere in wirtschaftlicher Hinsicht erhebliche Vorteile im Vergleich zum bekannten Verfahren aus dem Stand der Technik aufweist. Sowohl die Investitionskosten als auch die Produktionskosten sind signifikant geringer.

The subject matter according to the invention will be explained in more detail using the following figures, without wishing to limit it to the specific embodiments shown here.

• 1 shows a flow diagram of a process known in the prior art for electrolysis-based educt gas production and educt gas purification with separate provision of H ₂ and N ₂ for the downstream synthesis of NH ₃ . The downstream synthesis of NH ₃ is no longer shown.
• 2 shows a flow diagram of a method according to the invention for producing an educt gas mixture containing or consisting of hydrogen and nitrogen. A gas that contains or consists of water vapor 1, but no air, is introduced into a cathode of a first SOEC stack 2, which has an anode and a cathode, with water vapor 1 in the first SOEC stack 2 oxygen and hydrogen are partially produced and oxygen and hydrogen are spatially separated, with at least 20% by volume of the water vapor, in relation to a total volume of the water vapor, not being converted into oxygen and hydrogen. Oxygen 3 is discharged as exhaust gas from the anode of the first SOEC stack 2. A mixture 4 containing or consisting of hydrogen and unreacted water vapor is introduced from the cathode of the first SOEC stack 2 into a burner 5, with additional air 6 and additional water vapor 7 being introduced into the burner 5, the additional water vapor 7 having a temperature in the range from 100 °C to 150 °C. In the burner 5, a gas 8 is created from the mixture 4, the air 6 and the additional water vapor 7, which contains or consists of water vapor, nitrogen and at least 5% by volume of hydrogen, based on the total volume of the gas. This gas 8 is introduced from the burner 5 into a cathode of a second SOEC stack 9, which has an anode and a cathode, oxygen and hydrogen being produced in the second SOEC stack 9 from the water vapor of the gas 8 and oxygen and hydrogen be spatially separated. The oxygen 10 is discharged as exhaust gas from the anode of the second SOEC stack 9 and a mixture 11, which contains or consists of hydrogen, nitrogen and unreacted water vapor, is discharged from the cathode of the second SOEC stack 9. The mixture 11 is introduced into a cooling device 20, with water vapor condensing into water in the cooling device 20 and the condensed water being separated from the mixture, forming an educt gas mixture containing or consisting of hydrogen and nitrogen. No more than the first SOEC stack 2 and the second SOEC stack 9 are used in the method. In the 2 The arrangement and use of the first countercurrent heat exchanger 12, the second countercurrent heat exchanger 13, the third countercurrent heat exchanger 14 and the fourth countercurrent heat exchanger 15 are also illustrated. Furthermore, the arrangement and use of the first heating device 16, the second heating device 17, the third heating device 18 and the fourth heating device 19 are shown. Apart from this, the optional embodiment can be seen in which a mixture 21 of hydrogen, nitrogen and ammonia, which was discharged from a Haber-Bosch cycle, is supplied to the anode of the first SOEC stack 2 via the third heating device 18 and to the anode of the second SEOC stack 9 is fed via a fourth heating device 19.
• 3 shows a comparison based on an evaluation of the specific energy requirement (ε), the investment costs (TCI) and the production costs (TPC) between the method according to the invention, which only requires two SOEC stacks, and a known method from the prior art, which uses eight SOEC stacks (see WO 2019/ 072 608 A1 ) in the case of production of an amount of hydrogen and nitrogen that allows a production capacity of 1000 tNH ₃ /day. The evaluation included both a process simulation and a cost-effectiveness calculation for a so-called “2050 scenario”. The methodology used to assess economic viability is described in detail in HERZ, Gregor [et al.]: Economic assessment of Power-to-Liquid processes - Influence of electrolysis technology and operating conditions. In: Applied Energy, Vol. 292, 2021, article number: 116655 (18 p.) . - ISSN 0306-2619 (p); 1872-9118 (e). DOI: 10.1016/j.apenergy.2011.116655 and JACOBASCH, Eric [et al.]: Economic evaluation of low-carbon steelmaking via coupling of electrolysis and direct reduction. In: Journal of Cleaner Production, Vol. 328, 2021, article number: 129502 (21 pages). - ISSN 0959-6526 (p); 1879-1786 (e). DOI: 10.1016/j.jclepro.2021.129502 and was carried out in an identical manner for the method according to the invention and the method known in the prior art. An exclusive consideration of the educt gas production was not helpful at this point, since the heat integration between ammonia synthesis and educt gas production is particularly important for the energy efficiency and economic viability of the process. It can be seen from this figure that the method according to the invention has significant advantages, particularly from an economic point of view, compared to the known method from the prior art. Both the investment costs and the production costs are significantly lower.

Reference symbol list

1

Steam;

2

first SOEC stack;

3

Oxygen as exhaust gas from the first SOEC stack;

4

Mixture containing or consisting of hydrogen and unreacted water vapor;

5

Burner;

6

Air;

7

additional water vapor (temperature in the range of 100 to 150 °C);

8th

Gas containing or consisting of water vapor, nitrogen and at least 5% hydrogen by volume of the total volume of the gas;

9

second SOEC stack;

10

Oxygen as exhaust gas from the second SOEC stack;

11

Mixture containing or consisting of hydrogen, nitrogen and unreacted water vapor;

12

first countercurrent heat exchanger;

13

second countercurrent heat exchanger;

14

third countercurrent heat exchanger;

15

fourth countercurrent heat exchanger;

16

first heating device;

17

second heater;

18

third heater;

19

fourth heater;

20

cooling device;

21

Mixture of hydrogen, nitrogen and ammonia that was removed from a Haber-Bosch cycle.

Claims (18)

Process for producing an educt gas mixture containing or consisting of hydrogen and nitrogen, comprising the following steps: a) introducing a gas which contains or consists of water vapor (1) but no air (6) into a cathode of a first SOEC Stack (2), which has an anode and a cathode, wherein in the first SOEC stack (2) oxygen and hydrogen are partially produced from the water vapor (1) and oxygen and hydrogen are spatially separated, with at least 20% by volume of the water vapor (1), in relation to a total volume of the water vapor (1), is not converted into oxygen and hydrogen; b) removing the oxygen from the anode of the first SOEC stack (2) as exhaust gas (3); c) discharging a mixture (4), which contains or consists of hydrogen and unreacted water vapor, from the cathode of the first SOEC stack (2) into a burner (5), with additional air (6) being fed into the burner (5). and additional water vapor (7) is introduced, the additionally introduced water vapor (7) having a temperature of 100 ° C to 150 ° C, in which the burner (5) consists of the mixture (4), the additionally introduced air (6) and the additionally introduced water vapor (7) creates a gas (8) which contains or consists of water vapor, nitrogen and at least 5% by volume of hydrogen, in relation to the total volume of the gas (8); d) introducing the gas (8) from the burner (5) into a cathode of a second SOEC stack (9), which has an anode and a cathode, wherein in the second SOEC stack (9) the water vapor of the gas ( 8) oxygen and hydrogen are produced and oxygen and hydrogen are spatially separated, with at least 20% by volume of the water vapor, based on a total volume of the water vapor, not being converted into oxygen and hydrogen; e) discharging oxygen from the anode of the second SOEC stack (9) as exhaust gas (10); and f) discharging a mixture (11) containing or consisting of hydrogen, nitrogen and unreacted water vapor from the cathode of the second SOEC stack (9) into a cooling device (20), wherein water vapor is condensed into water in the cooling device (20) and the condensed water is separated from the mixture (11), resulting in an educt gas mixture containing or consisting of hydrogen and nitrogen; wherein no more than two SOEC stacks (2, 9) are used in the method. Method according to the preceding claim, characterized in that the gas introduced into the cathode of the first SOEC stack (2) i) has a temperature of ≥800 °C; and/or ii) is introduced into the cathode of the first SOEC stack (2) with a material stream which amounts to 17.5% of the material flow of an educt gas mixture that is to be provided by the method; and/or iii) is introduced into the cathode of the first SOEC stack (2) via a first countercurrent heat exchanger (12), preferably also via a second countercurrent heat exchanger (13), particularly preferably also via a first heating device (16), whereby the Gas is heated in the first countercurrent heat exchanger (12), the second countercurrent heat exchanger (13) and / or the first heating device (16), preferably to a temperature of at least 800 ° C. Method according to one of the preceding claims, characterized in that the first SOEC stack (2) and/or second SOEC stack (9) has a temperature of 700 °C to 900 °C, preferably 750 °C to 850 °C, in particular 800 °C. Method according to one of the preceding claims, characterized in that the removal of the oxygen from the anode of the first SOEC stack (2) and/or from the anode of the second SOEC stack (9) as exhaust gas (3, 10) via a second Countercurrent heat exchanger (13), optionally also via a third countercurrent heat exchanger (14), the oxygen being cooled in the second and/or third countercurrent heat exchanger (13, 14), the countercurrent heat exchangers (13, 14) preferably each having a degree of 100 °C. Method according to one of the preceding claims, characterized in that the burner (5) i) is supplied with the mixture (4), which contains or consists of hydrogen and unreacted water vapor (1), at a temperature of 700 to 900 ° C, preferably 750 °C to 850 °C, in particular 800 °C, is supplied; and/or ii) the additional air (6) is supplied at a temperature of 20 °C to 30 °C; and/or iii) the additional air (6) is supplied with a stream which amounts to 33% of the stream of a reactant gas mixture that is to be provided by the process; and/or iv) the additional water vapor (7) is supplied with a stream which amounts to 83% of the stream of an educt gas mixture that is to be provided by the process; and/or v) the additional water vapor (7) is supplied via a fourth countercurrent heat exchanger (15), particularly preferably also a third countercurrent heat exchanger (14), in particular also via a second heating device (17), the additional water vapor (7) being supplied in the fourth countercurrent heat exchanger (15), the third countercurrent heat exchanger (14) and / or the second heating device (17), particularly preferably from a temperature of 100 ° C to a temperature of >100 ° C to 150 ° C. Method according to one of the preceding claims, characterized in that the gas (8) from the burner (5), which is introduced into the cathode of the second SOEC stack (9), preferably has a temperature in the range of 700 to 900 °C 750 ° C to 850 ° C, in particular 800 ° C. Method according to one of the preceding claims, characterized in that discharging the mixture (11) containing or consisting of hydrogen, nitrogen and at least 20% by volume of water vapor, with respect to the total volume of the gas, from the cathode of the second SOEC -Stacks (9), via a first countercurrent heat exchanger (12), optionally also via a fourth countercurrent heat exchanger (15), the mixture (11) being cooled in the first and/or fourth countercurrent heat exchanger (12, 15), the Countercurrent heat exchangers (12, 15) preferably each have a degree of 100 ° C. Method according to one of the preceding claims, characterized in that a part of the mixture (11) discharged from the cathode of the second SOEC stack (9) is introduced back into the cathode of the first SOEC stack (2), preferably via a first countercurrent heat exchanger (12), particularly preferably also via a second countercurrent heat exchanger (13), very particularly preferably also via a first heating device (16), the mixture (11) being in the first countercurrent heat exchanger (12), the second countercurrent heat exchanger (13) and/or the first heating device (16) is heated, preferably to a temperature of at least 800 ° C. Method according to one of the preceding claims, characterized in that a mixture (21) of hydrogen, nitrogen and Ammonia, which was discharged from a Haber-Bosch cycle, i) is fed to the anode of the first SOEC stack (2), preferably via a third heating device (18), the mixture (21) of hydrogen, nitrogen and ammonia in the third heating device (18) is heated, preferably to a temperature of >_ 750 ° C; and/or ii) is supplied to the anode of the second SOEC stack (9), preferably via a fourth heating device (19), wherein the mixture (21) of hydrogen, nitrogen and ammonia is heated in the fourth heating device (19), preferably to a temperature of ≥ 750 °C. Plant for producing an educt gas mixture containing or consisting of hydrogen and nitrogen a) a first SOEC stack (2), which has an anode and a cathode and is configured to partially produce oxygen and hydrogen from a gas that contains or consists of water vapor (1) but no air (6), and to separate spatially and not to convert at least 20% by volume of the water vapor (1), in relation to a total volume of the water vapor (1), into oxygen and hydrogen; b) a burner (5) which is configured to produce a gas (8) from a mixture (4) which is discharged from the first SOEC stack (2) as well as additional air (6) and additional water vapor (7), which contains or consists of water vapor, nitrogen and at least 5% by volume of hydrogen, based on the total volume of the gas (8); c) a second SOEC stack (9), which has an anode and a cathode and is configured to partially produce oxygen and hydrogen from water vapor and thereby spatially separate and at least 20% by volume of the water vapor, in relation to a total volume of the water vapor, not to convert into oxygen and hydrogen; d) a cooling device (20) configured to produce condensed water and a reactant gas containing or consisting of hydrogen and nitrogen from a mixture (11) discharged from the second SOEC stack (9); wherein the system contains no more than two SOEC stacks (2, 9), the system being configured, to introduce a gas that contains or consists of water vapor (1) but no air (6) into the cathode of the first SOEC stack (2), to discharge oxygen from the anode of the first SOEC stack (2) as exhaust gas (3); a mixture (4) which contains or consists of hydrogen and unreacted water vapor (1) from the cathode of the first SOEC stack (2) into the burner (5) and additionally air (6) and additionally water vapor (7 ) into the burner (5), the additional water vapor (7) having a temperature in the range of 100 ° C to 150 ° C, to discharge oxygen from the anode of the second SOEC stack (9) as exhaust gas (10); and a mixture (11) containing or consisting of hydrogen, nitrogen and unreacted water vapor from the cathode of the second SOEC stack (9) into the cooling device (20). Annex according to Claim 10 , characterized in that the system is configured, the gas containing or consisting of water vapor (1), but no air (6), i) at a temperature of ≥800 ° C into the cathode of the first SOEC stack ( 2) initiate; and/or ii) to introduce a material flow into the cathode of the first SOEC stack (2) which amounts to 17.5% of the material flow of a reactant gas mixture that is to be provided with the system; and/or iii) via a first countercurrent heat exchanger (12), preferably also via a second countercurrent heat exchanger (13), particularly preferably also via a first heating device (16), to introduce the system into the cathode of the first SOEC stack (2), whereby the first countercurrent heat exchanger (12), the second countercurrent heat exchanger (13) and/or the first heating device (16) are configured to heat the gas, preferably to a temperature of at least 800 °C. Installation according to one of the Claims 10 or 11 , characterized in that the first SOEC stack (2) and / or the second SOEC stack (9) is configured to have a temperature of 700 ° C to 900 ° C, preferably 750 ° C to 850 ° C, in particular 800 ° C, to have. Installation according to one of the Claims 10 until 12 , characterized in that the system is configured to extract the oxygen from the anode of the first SOEC stack (2) and/or from the anode of the second SOEC stack (9) as exhaust gas (3, 10) via a second countercurrent heat exchanger (13 ), optionally also via the third countercurrent heat exchanger (14), the system, wherein the second countercurrent heat exchanger (12) and / or third countercurrent heat exchanger (14) is configured to cool the oxygen, the countercurrent heat exchangers (12, 13, 14) preferably each have a temperature of 100 °C. Installation according to one of the Claims 10 until 13 , characterized in that the system is configured to supply the burner (5) i) the mixture (4) from the first SOEC stack (2) at a temperature of 700 to 900 ° C, preferably 750 ° C to 850 ° C, in particular 800 ° C; and/or ii) the additional air (6) with a temperature of 20 °C to 30 °C; iii) supplying the additional air (6) with a material flow which amounts to 33% of the material flow of an educt gas mixture that is to be provided with the system; and/or iv) to supply the additional water vapor (7) with a material stream which amounts to 83% of the material flow of an educt gas mixture that is to be provided with the system; and/or v) supplying the additional water vapor (7) to the system via a fourth countercurrent heat exchanger (15), particularly preferably also via a third countercurrent heat exchanger (14), in particular also via a second heating device (17), the fourth countercurrent heat exchanger (15 ), the third countercurrent heat exchanger (14) and / or the second heating device (17) are configured to heat a mixture containing water and steam (7) so that water contained in the mixture completely evaporates to water vapor (7), particularly preferably to one Temperature from >100 °C to 150 °C. Installation according to one of the Claims 10 until 14 , characterized in that the system is configured to feed the gas (8) from the burner (5) into the cathode at a temperature in the range from 700 to 900 °C, preferably 750 °C to 850 °C, in particular 800 °C of the second SOEC stack (9). Installation according to one of the Claims 10 until 15 , characterized in that the system is configured to discharge the mixture (11), which contains or consists of hydrogen, nitrogen and water vapor (1), from the cathode of the second SOEC stack (9) via a first countercurrent heat exchanger (12), optionally also via a fourth countercurrent heat exchanger (15), the system, wherein the first countercurrent heat exchanger (12) and / or fourth countercurrent heat exchanger (15) are preferably configured to cool the mixture (11), the countercurrent heat exchangers (12, 15) preferably each have a temperature of 100 °C. Installation according to one of the Claims 10 until 16 , characterized in that the system is configured to direct part of the hydrogen and nitrogen discharged from the cathode of the second SOEC stack (9) back into the cathode of the first SOEC stack (2), preferably via a first countercurrent heat exchanger (12 ), particularly preferably also via a second countercurrent heat exchanger (13), very particularly preferably also via a first heating device (16), of the system, wherein the first countercurrent heat exchanger (12), the second countercurrent heat exchanger (12) and / or the first heating device (16 ) are configured to heat the hydrogen and nitrogen, preferably to a temperature of at least 800 ° C. Installation according to one of the Claims 10 until 17 , characterized in that the system is configured to supply a mixture (21) of hydrogen, nitrogen and ammonia, which was discharged from a Haber-Bosch cycle, i) to the anode of the first SOEC stack (2), preferably via a third heating device (18) of the system, wherein the third heating device (18) is configured to heat the mixture (21) of hydrogen, nitrogen and ammonia, preferably to a temperature of ≥ 750 ° C; and/or ii) to supply the anode of the second SOEC stack (9), preferably via a fourth heating device (19) of the system, wherein the fourth heating device (19) of the system is configured to supply the mixture (21) of hydrogen, nitrogen and Heating ammonia, preferably to a temperature of ≥ 750 °C.

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