BE1029714B1 - Ammonia synthesis with CO2-neutral hydrogen - Google Patents

Abstract

The present invention relates to a device and a method for the CO2-neutral production of hydrogen and subsequent further processing into ammonia.

Description

Ammonia synthesis with CO2-neutral hydrogen

The invention relates to a device and a method for CO2 neutralization

Hydrogen production and subsequent processing to ammonia.

Today, most of the hydrogen for ammonia synthesis is produced from methane using steam reforming. Due to the large volume of manufactured

Ammonia has a major impact on global CO2 emissions.

It is therefore desirable to reduce CO2 emissions. one discussed

One possibility is the production of hydrogen by means of electrolysis with electricity from renewable energy sources, for example from solar power. Because of the high

Due to the energy requirement for the electrochemical water splitting, however, this process is energetically unfavorable and therefore comparatively expensive. However, it has a high

Permission in the conversion of, for example, solar power, for example, in

Ammonia as an easy-to-store, easy-to-transport, and easy-to-recover form of energy storage.

However, in order to be able to meet the high demand, especially in the fertilizer industry, in a cost-sensitive manner, it makes sense to look for alternatives.

The thermal decomposition of hydrocarbons and the synthesis of ammonia is known from US Pat. No. 7,094,384 B1.

WO 2002 038 499 A1 discloses a method for producing ammonia from a

Known nitrogen-hydrogen mixture from natural gas.

The synthesis of ammonia is known from US 2019 0144768 A1.

The object of the invention is to provide an inexpensive but CO2-free hydrogen source for large-scale ammonia synthesis.

This object is achieved by the device specified in claim 1

Features and by the method with the features specified in claim 9.

° BE2021/5673

Advantageous developments result from the subclaims below

description and the drawings.

The ammonia synthesis device according to the invention is used to generate

hydrogen and to convert the hydrogen into ammonia. The

Ammonia synthesis device has a converter for converting nitrogen and

hydrogen to ammonia. Corresponding converters are known to those skilled in the art and usually run according to the Haber-Bosch process, ie at an increased

Temperature and high pressure on a corresponding catalyst. The

Ammonia synthesis device a separation device for separating the

Ammonia from the gas stream. This is also from the classic Haber-Bosch

procedure known. The ammonia synthesis device has a reactant inlet and a product outlet, and the separation device has a gas mixture inlet and a reactant gas outlet. The product output of

Ammonia synthesis device is connected to the gas mixture input

Separation device connected and the educt gas outlet

Separation device is connected to the educt input of the ammonia synthesis device. As a result, unreacted gas mixture of hydrogen and

nitrogen in a circle, like this one from the classic Haber-Bosch

procedure is known. The product outlet of the ammonia synthesis device is connected to the gas mixture inlet of the separation device via a first heat exchanger. In this way, the heat of the exothermic process generated during the ammonia synthesis can be dissipated.

According to the invention, the ammonia synthesis device has a pyrolysis reactor

Conversion of hydrocarbon into carbon and hydrogen. The

Pyrolysis reactor has a hydrocarbon inlet and a hydrogen outlet. The hydrogen output of the pyrolysis reactor is connected to the reactant input

Ammonia synthesis device connected. Next is the educt gas outlet

Separation device connected to the hydrocarbon inlet of the pyrolysis reactor. In a pyrolysis reactor, a hydrocarbon is converted into carbon (solid) and

Hydrogen (gaseous) separated. In contrast to the current process of steam reforming and a subsequent water-gas shift

Reaction no CO2, but carbon in solid form. This can be stored comparatively safely in order to safely avoid CO2 emissions. Likewise he can

Carbon can also be reused in a way that does not cause CO2 emissions. 5 Since the pyrolysis is not complete, a certain amount of hydrocarbons can remain in the hydrogen stream. Since then in the ammonia synthesis

If there is a circuit between the converter and the separation device, these hydrocarbons would accumulate over time. To solve this problem, a partial flow is separated between the separation device and the converter and returned to the pyrolysis reactor, where the hydrocarbons can be pyrolyzed. This results in a low but stable level of hydrocarbons in the

Ammonia synthesis cycle.

Another effect is that, in contrast to steam reforming, pyrolysis does not

carbon monoxide can form. It can therefore rely on a device for converting carbon monoxide into methane between the steam reformer and the actual

Haber-Bosch process can be dispensed with.

In a further embodiment of the invention, a methanizer is arranged after the pyrolysis reactor and before the converter. For example, if pure methane was used as the starting material, this step, which is usually necessary after steam reforming, would be unnecessary, since without oxygen, no carbon monoxide can form as a catalyst poison. However, there are natural gas deposits that contain carbon dioxide and/or carbon monoxide. When using such a starting material, it would make sense to use a methanizer to convert any carbon monoxide present with hydrogen to form methane and carbon dioxide, in order to protect the catalyst in the converter.

In a further embodiment of the invention, the ammonia synthesis reactant gas stream leaving the separation device is divided by means of a controllable valve into a first part stream to the converter and a second part stream to the pyrolysis reactor.

The controllable valve is particularly preferably connected to a control device, the control device being connected to an analysis device, the

Analysis device within the ammonia synthesis educt gas stream between the

* BE2021/5673

Separation device and the converter including the first partial flow or within the ammonia synthesis educt gas flow between the converter and the

Separating device is arranged. The analyzer is for quantitative

Detection of hydrocarbons trained. This includes for quantitative

Detection of hydrocarbons both a direct detection of the concentration of

Hydrocarbons as well as the detection of a size with the concentration of

Hydrocarbons is correlated, for example, the heat capacity. The higher the

The concentration of hydrocarbons within the Haber-Bosch cycle is the larger the proportion of the second partial flow is selected in relation to the first partial flow by the control device controlling the controllable valve accordingly.

In a further embodiment of the invention, the

Ammonia synthesis device on an air separation device. The

Air separation device has a nitrogen outlet, the nitrogen outlet of the air separation device being connected to the educt inlet of the ammonia synthesis device. The nitrogen outlet of the air separation device is preferably connected to the educt inlet of the ammonia synthesis device via a nitrogen compressor. The air separation device further includes an oxygen outlet.

The oxygen can either be used in other processes or simply attached to the

ambient air are released. Preferably, the air separation device has a

Membrane for air separation, as this is more energy efficient than air separation using the Linde process. Alternatively, for example, nitrogen from the

Evaporation of liquid nitrogen can be obtained.

In another embodiment of the invention, the nitrogen outlet is the

Air separation device connected to the educt inlet of the ammonia synthesis device via an oxygen filter device. Since after a pyrolysis process there is no guarantee that the hydrogen stream does not contain any hydrocarbons, it would be critical if oxygen was also introduced in a low concentration, as this would

Carbon monoxide could arise, which in turn is to be avoided as a catalyst poison. For example, an oxygen filter device may have a large surface area of a readily corrosive material, such as a base metal.

As a result, possible oxygen is chemically bound to the surface. The effect

) BE2021/5673 can be enhanced by a magnetic field since oxygen is paramagnetic and

nitrogen is diamagnetic.

In another embodiment of the invention, the nitrogen outlet is the

Air separation device via the first heat exchanger with the reactant input

Ammonia synthesis device connected. In this way, it is comparatively easy to bring the stream of nitrogen to the temperature at which it is

Feeding to the converter should have.

In a further embodiment of the invention, the first heat exchanger with a

Connected heat exchange fluid system. The nitrogen outlet of the

Air separation device is connected via the second heat exchanger to the educt inlet of the ammonia synthesis device. Next, the hydrocarbon input of the pyrolysis reactor is connected to a hydrocarbon source, wherein the

Hydrocarbon input of the pyrolysis reactor is connected via a third heat exchanger to a hydrocarbon source. The second heat exchanger and the third

Heat exchangers are connected to the heat exchange fluid system. This makes it possible on the first heat exchanger via a heat exchanger fluid to the second

To give heat exchanger and to the third heat exchanger and to heat both reactant streams.

In a further embodiment of the invention, the hydrocarbon input is

Pyrolysis reactor connected to a hydrocarbon source, wherein the

Hydrocarbon input of the pyrolysis reactor is connected via the first heat exchanger to a hydrocarbon source.

In a further embodiment of the invention, the hydrogen output is

Pyrolysis reactor via a first compressor with the reactant inlet

Ammonia synthesis device connected. Next is the educt gas outlet

Separation device via an expansion device with the

Hydrocarbon input connected to the pyrolysis reactor. The first compressor is coupled to the expansion device. The Haber-Bosch

Process under very high pressures to shift the equilibrium to the product ammonia. Pyrolysis, on the other hand, is often carried out at lower pressures. Around

° BE2021/5673 to use the energy given off by the gas returned to the pyrolysis reactor when it is brought from a high pressure to a lower pressure level of the pyrolysis reactor, the first compressor is coupled to the expansion device, for example via only one common axis.

In a further embodiment of the invention, the pyrolysis reactor is designed for a pressure of 1 bar to 20 bar and a temperature of 600°C to 1500°C. The pyrolysis reactor is particularly preferably designed for a pressure of 2 bar to 10 bar.

With regard to temperature, there are different optimal temperature ranges, which can be traced back to different types of pyrolysis. The pyrolysis reactor preferably has a molten metal, a moving bed or a plasma. These technologies of pyrolysis of hydrocarbons as technologically mature for large-scale

use exposed. Therefore, the pyrolysis reactor, for example, for a

be designed for a temperature range of 600 °C to 900 °C. This is optimal, for example, for a molten metal pyrolysis reactor. Alternatively, the pyrolysis reactor can be designed for a temperature range from 900°C to 1500°C, preferably from 1200°C to 1500°C.

The pyrolysis reactor can particularly preferably be designed according to WO 2019/145279 A1.

In a further embodiment of the invention, the pyrolysis reactor has an electrical heater. This makes it possible to avoid CO2 emissions for generating the energy required for pyrolysis by using electricity from renewable energy sources.

In a further aspect, the invention relates to a method for synthesizing ammonia from a hydrocarbon, the method having the following steps: a) feeding a hydrocarbon into a pyrolysis reactor, b) pyrolyzing the hydrocarbon to form carbon and hydrogen in the

Pyrolysis reactor, c) conducting the hydrogen from the pyrolysis reactor into a converter, d) supplying nitrogen to the converter, e) converting the hydrogen and the nitrogen into ammonia in the converter,

' BE2021/5673 f) cooling the ammonia synthesis product gas stream in a first

heat exchanger, g) separating the ammonia from the ammonia synthesis product gas stream in a

Separation device and receipt of an ammonia synthesis feed gas stream,

Ie) dividing the ammonia synthesis feed gas stream into a first part stream and a second part stream, ) passing the first part stream into the converter,

Î) Conducting the second partial flow into the pyrolysis reactor.

The method according to the invention is preferably carried out on a device according to the invention

device performed.

Through the process steps h) and j), part of the

Ammonia synthesis feed gas stream recycled to contained therein

Decompose hydrocarbons and thus prevent accumulation.

In a further embodiment of the invention, the pyrolysis in step b) takes place non-catalytically. A purely thermal pyrolysis therefore preferably takes place.

In a further embodiment of the invention, methane is pyrolyzed in step b).

On the one hand, the pyrolysis of methane is advantageous in itself, on the other hand, it is also mainly used in the steam reforming used today for ammonia synthesis

Methane used, so that a conversion to the method according to the invention is relatively easy and when using the existing ones

Supply infrastructure capable of significantly reducing CO2 emissions.

In a further embodiment of the invention, when feeding the

Hydrocarbon in step a) of this by means of the in the first heat exchanger

Ammonia synthesis product gas stream heats withdrawn energy.

In a further embodiment of the invention, when the nitrogen is supplied in

Step d) this by means of the heat exchanger in the first

Ammonia synthesis product gas stream heats withdrawn energy.

° BE2021/5673

In a further embodiment of the invention, the hydrogen stream is compressed when being passed from the pyrolysis reactor into the converter in step c).

In a further embodiment of the invention, the second partial flow is relaxed, with the energy gained through the relaxation being used to compress the

Hydrogen stream is used. This can preferably be done in that the first

Compressor and the relaxation device, for example, via a common

shaft are coupled.

In a further embodiment of the invention, the pyrolysis reactor and the

Converter operated at the same pressure. This embodiment is particularly preferred since energy losses through compression and decompression are avoided in this way. On the other hand, this embodiment represents very high

Requirements for the pyrolysis reactor in order to avoid soot formation in the gas phase, since the comparatively high pressure and the resulting lower average distance between the molecules in the gas phase means that there is a risk of the formation of

Carbon particles in the gas phase is comparatively high.

In a further embodiment of the invention, the sharing of the

Ammonia synthesis feed gas stream in step h) depending on the

Hydrocarbon content of the ammonia synthesis feed gas stream. In particular, the hydrocarbon content in the ammonia synthesis feed gas stream or in the

Ammonia synthesis product gas stream detected directly or indirectly. Direct detection would be possible, for example, using IR, and indirect detection would be possible, for example, using thermal conductivity measurement. The higher the recorded

Hydrocarbon content is, the higher the proportion of the second partial stream is set.

In a further embodiment of the invention, the pyrolysis reactor is electrically heated. This makes it particularly easy to use energy from a regenerative energy source and therefore without CO2 emissions. For this purpose, the ammonia synthesis device particularly preferably has a wind power plant, a solar plant and an energy store. Due to this energy mix and the intermediate storage

) BE2021/5673, continuous operation is relatively reliable. If necessary, electrical energy can be drawn from a public supply network.

In a further embodiment of the invention, the carbon which is produced in step b) is deposited, ie finally stored. In this way, an entry of carbon in the form of CO: into the atmosphere is avoided in the long term and safely.

The device according to the invention is explained in more detail below with reference to exemplary embodiments illustrated in the drawings.

Fig. 1 first embodiment

Fig. 2 second embodiment

Fig. 3 third embodiment

Fig. 4 fourth embodiment

Fig. 5 fifth embodiment

Fig. 6 sixth embodiment

The same components are in each case with the same in the following exemplary embodiments

provided with reference numbers.

The first exemplary embodiment is described in more detail below, and the differences are discussed in the further exemplary embodiments.

In Fig. 1 is a first embodiment of an inventive

Ammonia synthesizer 10 is shown. The ammonia synthesis device 10 has a hydrocarbon source 150, for example a connection to a

methane gas network. The hydrocarbon is conducted via a hydrocarbon inlet 100 into a pyrolysis reactor 90 and is converted there thermally, for example at 1200° C. to 1500° C., to form carbon and hydrogen. For example, is the

Pyrolysis reactor designed as a moving bed reactor, with cold hydrocarbon being introduced at the bottom. This rises while the hydrocarbon is heated by countercurrent carbon, which in turn cools the carbon. In the middle of the pyrolysis reactor 90, the carbon particles are electrically heated, which leads to pyrolysis of the hydrocarbon and thus to growth of the

carbon leads. As it continues to rise, the hydrogen heats the oncoming carbon, with the hydrogen preferentially growing to the size of the

Temperature of the Haber-Bosch process is cooled. The hydrogen leaves the

Pyrolysis reactor 90 through the hydrogen outlet 110. The hydrogen stream 190 is compressed with the first compressor 160 and fed to the educt inlet 40 of the converter 20. Since the hydrogen stream 190, in contrast to steam reforming, does not

Has nitrogen, the nitrogen is supplied separately. The

Ammonia synthesis device 10 an air separation device 120 on. The nitrogen leaves the air separation device 120 via the nitrogen outlet 130. The

In the example shown, a stream of nitrogen is routed via an optional oxygen filter device 140 to the educt inlet 40 of the converter 20 . In the converter 20 takes place

Conversion of nitrogen and hydrogen to ammonia. The ammonia synthesis product gas stream 210 leaves the converter 20 via the product outlet 50 and is fed into the separation device 30 via the first heat exchanger 80 via the

Gas mixture input 60 of the separation device 30 is fed. Here the product

Ammonia separated and via the ammonia outlet 230, for example, one

supplied to urea synthesis. What remains is a mixture of unreacted ones

Hydrogen and unreacted nitrogen, which optionally

May have hydrocarbons, which were not or not fully implemented in the pyrolysis reactor. This mixture leaves the separation device 30 as the ammonia synthesis reactant gas stream 200 via the reactant outlet 70. Most of the ammonia synthesis reactant gas stream 200 is fed back directly to the reactant inlet 40 of the converter 20 as the first substream 240. Another part of

Ammonia synthesis reactant gas stream 220 is separated as a second partial stream 250 at valve 270 and as a second partial stream 250 to the hydrocarbon inlet 100 of the

Pyrolysis reactor 90 fed back. Since the ammonia synthesis usually takes place under much higher pressures, the second partial stream 250 is a

Relaxation device 170 arranged, which is connected to the first compressor 160 via a coupling to use the released energy. To the

Discharging carbon from the pyrolysis reactor 90 has this one

carbon exit 260 on.

As already described, in the following only the differences to the first one will be mentioned

embodiment received.

The second exemplary embodiment shown in FIG. 2 differs by the first

Embodiment in that the stream of nitrogen directly through the first

Heat exchanger 80 is performed, and so directly by the process heat

Ammonia synthesis is heated.

3 shows the third exemplary embodiment, in which the hydrocarbon from the hydrocarbon source 150 is conducted directly through the first heat exchanger 80 and is thus heated. As a result, in particular the carbon emerging from the carbon outlet 260 can be comparatively warmer, which is why it could be used to heat the nitrogen flow 200, which is not shown here for the sake of simplicity.

The fourth embodiment shown in Fig. 4 has in addition to the first

Embodiment, a second heat exchanger 280 in the nitrogen stream 200 and a third heat exchanger 290 for heating the hydrocarbon between the

Hydrocarbon source 150 and the pyrolysis reactor 90 on. The first heat exchanger 80, the second heat exchanger 280 and the third heat exchanger 290 are one

Heat exchange fluid system interconnected, which is omitted here for simplicity. In this way, the process heat generated can be given off to both educt streams.

FIG. 5 shows a fifth exemplary embodiment, in which the pyrolysis reactor 90 operates at the same pressure level as the converter 20. For this purpose, the first compressor was moved from the hydrogen stream 190 and is now between the

Hydrocarbon source 150 and the pyrolysis reactor 90 arranged that

Relaxation device 170 and thus also the coupling 180 are omitted. In addition, a second compressor 300 is arranged in the nitrogen stream 200, which is preferably also present in the other exemplary embodiments.

The sixth embodiment is shown in Fig. 6 and differs from the first

Embodiment characterized in that the nitrogen stream does not flow into the hydrogen stream 190 and thus into the educt inlet 40 of the converter 20, but in the

Hydrocarbon input 100 of the pyrolysis reactor 90. The advantage of this

Embodiment is that thereby the probability of collision between

Hydrocarbon molecules and thus the formation of soot can be reduced.

The disadvantage of this is that the nitrogen also has to be heated to the pyrolysis temperature. However, this energy can be recovered again at the end of the pyrolysis reactor 90 .

Reference sign

Ammoniaksynthesevorrichtung 20 Konverter 10 30 —Abtrennungsvorrichtung 40 Edukteingang 50 Produktausgang 60 Gasgemischeingang 70 Eduktgasausgang 80 erste Wärmetauscher 90 Pyrolysereaktor 100 Kohlenwasserstoffeingang 110 Wasserstoffausgang 120 Luftzerlegungsvorrichtung 130 Stickstoffauslass 140 Sauerstofffiltervorrichtung 150 Kohlenwasserstoffquelle 160 erster Kompressor 170 Entspannungsvorrichtung 180 Kopplung 190 Wasserstoffstrom 200 Stickstoffstrom 210 Ammoniaksyntheseproduktgasstrom 220 Ammoniaksyntheseeduktgasstrom 230 Ammoniakausgang 240 first partial flow 250 second partial flow 260 carbon outlet 270 valve

280 second heat exchanger 290 third heat exchanger, 300 second compressor

Claims (15)

patent claims 1. Ammonia synthesis device (10) for generating hydrogen and for converting the hydrogen into ammonia, the ammonia synthesis device (10) having a converter (20) for converting nitrogen and hydrogen into ammonia, the ammonia synthesis device (10) having a separation device (30) for separating the ammonia from the gas stream, the ammonia synthesis device (10) having a reactant inlet (40) and a product outlet (50), the separation device (30) having a gas mixture inlet (60) and a reactant gas outlet (70), the product outlet (50) of the ammonia synthesis device (10) is connected to the gas mixture inlet (60) of the separation device (30), the reactant gas outlet (70) of the separation device (30) being connected to the reactant inlet (40) of the ammonia synthesis device, the product outlet (50) the ammonia synthesis device (10) is connected to the gas mixture inlet (60) of the separation device (30) via a first heat exchanger (80), characterized in that the ammonia synthesis device (10) has a pyrolysis reactor (90) for converting hydrocarbons into carbon and hydrogen, wherein the pyrolysis reactor (90) has a hydrocarbon inlet (100) and a hydrogen outlet (110), the hydrogen outlet (110) of the pyrolysis reactor (90) being connected to the reactant inlet (40) of the ammonia synthesis device (10), the reactant gas outlet (70) the separation device (30) is connected to the hydrocarbon inlet (100) of the pyrolysis reactor (90). 2. Ammonia synthesis device (10) according to claim 1, characterized in that the ammonia synthesis device (10) has an air separation device (120), the air separation device (120) having a nitrogen outlet (130), the nitrogen outlet (130) of the air separation device (120) is connected to the reactant inlet (40) of the ammonia synthesis device (10). 3. Ammonia synthesis device (10) according to claim 2, characterized in that the nitrogen outlet (130) of the air separation device (120) is connected to the reactant inlet (40) of the ammonia synthesis device (10) via an oxygen filter device (140). 4. Ammonia synthesis device (10) according to one of claims 2 to 3, characterized in that the nitrogen outlet (130) of the air separation device (120) is connected via the first heat exchanger (80) to the reactant inlet (40) of the ammonia synthesis device (10). 5. Ammonia synthesis device (10) according to any one of claims 2 to 3, characterized in that the first heat exchanger (80) is connected to a heat exchange fluid system, the nitrogen outlet (130) of the air separation device (120) being connected via the second heat exchanger (280) to the Educt inlet (40) of the ammonia synthesis device (10), the hydrocarbon inlet (100) of the pyrolysis reactor (90) being connected to a hydrocarbon source (150), the hydrocarbon inlet (100) of the pyrolysis reactor (90) being connected via a third heat exchanger (290) connected to a hydrocarbon source (150), the second heat exchanger (280) and the third heat exchanger (290) being connected to the heat exchange fluid system. 6. ammonia synthesis device (10) according to any one of claims 1 to 4, characterized in that the hydrocarbon inlet (100) of the pyrolysis reactor (90) is connected to a hydrocarbon source (150), the hydrocarbon inlet (100) of the pyrolysis reactor (90) via the first heat exchanger (80) is connected to a hydrocarbon source (150). 7. Ammonia synthesis device (10) according to one of the preceding claims, characterized in that the hydrogen outlet (110) of the pyrolysis reactor (90) is connected via a first compressor (160) to the reactant inlet (40) of the ammonia synthesis device (10), the reactant gas outlet (70) of the separation device (30) via an expansion device (170) with the hydrocarbon inlet (100) of Pyrolysis reactor (90) is connected, wherein the first compressor (160) is coupled to the expansion device (170). 8. ammonia synthesis device (10) according to any one of the preceding claims, characterized in that the pyrolysis reactor (90) is designed for a pressure of 1 bar to 20 bar and a temperature of 600 °C to 1500 °C. 9. A method of synthesizing ammonia from a hydrocarbon, the method comprising the steps of: a) feeding a hydrocarbon into a pyrolysis reactor (90), b) pyrolyzing the hydrocarbon into carbon and hydrogen in the pyrolysis reactor (90), c) passing the hydrogen from the pyrolysis reactor (90) into a converter (20), d) supplying nitrogen to the converter (20), e) converting the hydrogen and the nitrogen into ammonia in the converter (20), f) cooling the ammonia synthesis product gas stream (210) in a first heat exchanger (80), g) separating the ammonia from the ammonia synthesis product gas stream (210) in a separating device and obtaining an ammonia synthesis reactant gas stream (220), h) dividing the ammonia synthesis reactant gas stream (220) into a first part stream (240) and a second part stream ( 250), 1) passing the first partial flow (240) into the converter (20), j) passing the second partial flow (250) into the pyrolysis reactor (90). 10. The method according to claim 9, characterized in that when the hydrocarbon is fed in in step a), it is heated by means of the energy withdrawn from the ammonia synthesis product gas stream (210) in the first heat exchanger (80). 11. The method according to any one of claims 9 to 10, characterized in that when supplying the nitrogen in step d) of this by means of the first Heat exchanger (80) the ammonia synthesis product gas stream (210) withdrawn energy is heated. 12. The method according to any one of claims 9 to 11, characterized in that the hydrogen stream (190) is compressed when passing from the pyrolysis reactor (90) into a converter (20) in step c). 13. The method according to claim 12, characterized in that the second partial flow (250) is expanded, the energy obtained by the expansion being used to compress the hydrogen flow (190). 14. The method according to any one of claims 9 to 11, characterized in that the pyrolysis reactor (90) and the converter (20) are operated at the same pressure. 15. The method according to any one of claims 9 to 13, characterized in that the dividing of the ammonia synthesis feed gas stream (220) in step h) takes place depending on the hydrocarbon content of the ammonia synthesis feed gas stream (220).