LU103206B1 - Process and plant for the production of ammonia with autothermal reformer - Google Patents

Abstract

The present invention relates to a process for producing ammonia, comprising the steps of providing three reactant gases, namely a hydrocarbon-containing reactant gas, an air-based reactant gas and a steam-containing reactant gas, heating at least one of the three reactant gases with a fired burner device, wherein at least one heated reactant gas is obtained, feeding the at least one heated reactant gas and the remaining three reactant gases into an autothermal reformer, autothermally reforming the three reactant gases, wherein a reformed gas mixture is obtained, feeding the reformed gas mixture into an ammonia synthesis cycle with a synthesis cycle gas, converting the synthesis cycle gas in a converter, wherein ammonia is generated in the synthesis cycle gas, and dividing the synthesis cycle gas into a first partial stream and a second partial stream, characterized in that the first partial stream is fed to the fired burner device as hydrogen-containing fuel gas. Furthermore, the invention relates to a corresponding ammonia synthesis plant and a method for converting an ammonia synthesis plant.

Description

' LU103206

Process and plant for the production of ammonia with autothermal reformer

The invention is in the field of chemical plant engineering and relates to a

A process for producing ammonia, comprising the steps of providing three

Educt gases, namely a hydrocarbon-containing educt gas, an air-based

reactant gas and a vapor-containing reactant gas, heating at least one of the three reactant gases with a fired burner device, wherein at least one heated

Educt gas is obtained, feeding the at least one heated educt gas and the remaining three educt gases into an autothermal reformer, autothermal

Reforming the three reactant gases to obtain a reformed gas mixture, 11 feeding the reformed gas mixture into an ammonia synthesis cycle with a synthesis cycle gas, converting the synthesis cycle gas in a converter to produce ammonia in the synthesis cycle gas, and splitting the

Synthesis cycle gas into a first partial stream and a second partial stream.

The invention further relates to an ammonia synthesis plant with a

Synthesis gas generation device for generating a reformed reactant gas from a hydrocarbon-containing reactant gas, with an ammonia synthesis circuit for

Production of ammonia from a product conveyed in a synthesis cycle direction

Synthesis cycle gas, as well as a feed for feeding the reformed

reactant gas into the synthesis cycle gas, wherein the synthesis gas generation device and the ammonia synthesis cycle are fluidically connected via the feed, wherein the synthesis gas generation device has an autothermal

Reformer for producing the reformed reactant gas from an air-based

reactant gas, a vapor-containing reactant gas and the hydrocarbon-containing reactant gas as well as a gas heater with a fired burner device for heating the

reactant gas before feeding into the autothermal reformer, whereby the

Ammonia synthesis cycle a converter to produce a converted

Synthesis cycle gas from the synthesis cycle gas and a separation to

Separating the converted synthesis cycle gas into two partial streams, wherein the separation is connected to a discharge line for discharging one of the two partial streams zo. Finally, the invention relates to a method for converting a

Ammonia synthesis plant with a synthesis gas generation device for generating a reformed gas mixture using three reactant gases, namely a 230627P00LU hydrocarbon-containing reactant gas, an air-based reactant gas and a steam-containing reactant gas, an ammonia synthesis cycle for generating

Ammonia in a synthesis cycle direction conveyed

Synthesis cycle gas, as well as a feed for feeding the reformed

gas mixture into the synthesis cycle gas, whereby the

Synthesis gas generation device and the ammonia synthesis circuit are fluidically connected via the feed, whereby the

Synthesis gas generation device, an autothermal reformer for generating the reformed gas mixture using the three reactant gases and a gas heater

With a fired burner device for heating at least one of the three

reactant gases before feeding into the autothermal reformer, whereby the

Ammonia synthesis cycle a converter to produce ammonia in

Synthesis cycle gas.

Ammonia is one of the most important industrial chemicals with a worldwide

Annual production of more than 150 million tons, most of which is in the

For more than a century, ammonia has been produced on an industrial scale, primarily using the Haber-Bosch process, in which

Hydrogen and nitrogen are reacted with each other in a fixed-bed reactor over a catalyst. Since this is an equilibrium reaction, the

equilibrium is not on the side of the products, the reaction mixture with the unreacted gas components is transported to a

Ammonia synthesis cycle circulates. From this ammonia synthesis cycle (synthesis cycle, synthesis loop), ammonia is separated and unreacted

Hydrogen and nitrogen within the ammonia synthesis cycle are again

The amount of ammonia removed from the ammonia synthesis cycle as ammonia is replaced by a corresponding amount of hydrogen and nitrogen, which is fed into the ammonia synthesis cycle as fresh gas ("make-up gas"). Traditionally, the hydrogen required for the reaction is produced from natural gas, which is why a considerable amount of carbon dioxide is produced. zo In recent years, there has been increasing interest in a process that is as sustainable as possible.

Ammonia production. The focus here is particularly on "green ammonia," i.e., ammonia whose production does not release additional carbon dioxide into the atmosphere and does not use fossil fuels. 230627P00LU

In order to produce green ammonia, the hydrogen required must also be “green” and produced without additional carbon dioxide release and without the use of fossil fuels.

Fuels are produced. The production of green hydrogen is therefore typically carried out by electrolysis of water, for which the energy demand is met from renewable/regenerative energies. Given the currently available infrastructure for the generation of electrical energy from renewable

However, it is foreseeable that the energy demand of such an energy-intensive

technology cannot yet be fully covered worldwide using renewable energy sources exclusively. Therefore, at least temporarily, in addition to the production of green ammonia, other climate-optimised

Technologies are being used to sustainably reduce environmental impacts. One way to achieve this goal is the production of so-called "blue ammonia."

Blue ammonia is also released into the atmosphere without significant release of carbon dioxide.

Atmosphere, however, unlike the production of green ammonia, fossil fuels are used to produce hydrogen by reforming hydrocarbons. The resulting carbon dioxide is not released into the atmosphere, but captured and stored in carbon dioxide storage facilities. In this way, bluer

Hydrogen is obtained, which can be converted into blue ammonia. Therefore, in the production of blue ammonia, no significant amount of

Carbon dioxide is released, so that this method also results in a relatively climate-neutral

Production is possible (even in the production of blue ammonia,

Carbon dioxide is emitted, but the proportion of carbon dioxide that enters the

atmosphere, significantly lower than in conventional production of

Ammonia, in some cases 70-95% of the carbon dioxide that would otherwise be released is avoided).

Hydrogen is traditionally produced from natural gas in reformers, typically by steam reforming in multi-stage steam reformers or by partial oxidation. A combination of both processes is offered by autothermal

Reforming, which increases the efficiency of both processes.

In this process, part of the natural gas is oxidized substoichiometrically and the resulting

Reaction heat is used for catalytic steam reforming, which requires a controlled supply of the reactant streams (natural gas, air — or another oxidant — and steam). In autothermal reforming, the

Educt streams are preheated, for which purpose, in addition to the use of process waste heat — for example from the reformed gas — fired burners are also used, which are operated with a fuel gas. The fuel gas for the fired

Natural gas is typically used in the burner device.

Carbon dioxide is released, which must be captured in order to achieve a climate-neutral

To ensure the production of ammonia. The waste heat from the flue gas of the fired burner can also be used for preheating.

The object of the invention is to preheat the reactant streams for the

Ammonia production in the autothermal reformer can reduce the additional carbon dioxide release into the atmosphere without requiring significant additional effort in removing carbon dioxide.

This task is solved by a process for the production of ammonia with the

Claim 1, by an ammonia synthesis plant with the features specified in

Claim 8 and by a method for converting a

Ammonia synthesis plant with the features specified in claim 15. Advantageous

Further developments arise from the subclaims, the following

Description and drawings.

Such a method therefore comprises the steps a) providing three reactant gases, namely a hydrocarbon-containing reactant gas, an air-based reactant gas and a steam-containing reactant gas, b) heating at least one of the three

Educt gases with a fired burner device, wherein at least one heated

reactant gas is obtained, c) feeding the at least one heated reactant gas and the remaining three reactant gases into an autothermal reformer, d) autothermal

Reforming the three reactant gases to obtain a reformed gas mixture, e)

Feeding the reformed gas mixture into an ammonia synthesis cycle with a synthesis cycle gas, f) converting the synthesis cycle gas in a

converter, whereby ammonia is produced in the synthesis cycle gas, and g) dividing the synthesis cycle gas into a first partial stream and a second partial stream.

A characteristic feature is that the first partial flow of the fired burner device (burner, fired burner) is supplied as hydrogen-containing fuel gas. 230627P00LU

A process for the production of ammonia is a process in which starting materials

Ammonia is produced. Such a process is typically carried out in a

Ammonia synthesis plant. An ammonia synthesis plant is a plant designed to produce ammonia from hydrogen and nitrogen. Such a plant has an ammonia synthesis cycle (synthesis cycle), i.e. a section which is at least partially designed to be cyclically circulated for the reaction gas mixture and is designed so that within this

The synthesis of ammonia takes place in the ammonia synthesis cycle. As an essential functional element, the ammonia synthesis cycle has a converter (ammonia converter, synthesis reactor, ammonia synthesis reactor), which is designed to catalytically convert nitrogen and hydrogen at least partially to

Ammonia, usually according to the Haber-Bosch process. In the Haber-Bosch process

In this process, the reaction is typically carried out in the presence of an iron catalyst at

Temperatures in a range of approximately 350 °C to approximately 550 °C and at a pressure of more than 100 bar according to the reaction equation 3 Hz + Na = 2 NHs + 92.28 kJ/mol. The gas mixture circulating as synthesis cycle gas (cycle gas) has nitrogen, hydrogen, and ammonia as its main components, but may also contain other components if necessary. It is used in the

Converter, comes into contact with the catalyst and is discharged from the converter, whereby the discharged gas mixture in production operation has a higher ammonia content than the introduced gas mixture (and accordingly a lower nitrogen content and a lower

hydrogen content than the introduced gas mixture). Often a multi-stage

Converter is used in which the synthesis cycle gas is passed successively through two, three or more reaction chambers or reaction vessels, between which, to remove the heat generated during the reaction,

Heat exchangers are arranged, by means of which the synthesis cycle gas to be introduced into the individual reaction chambers or reaction vessels is passed through the

The synthesis cycle gas flowing out of the reaction chamber is preheated. In the ammonia synthesis cycle, the gas mixture is preheated with the help of a compressor in the

The compressor is designed and arranged to cyclically convey the gas mixture in the ammonia synthesis cycle in one conveying direction, the synthesis cycle direction. The conveying is carried out by 230627P00LU.

Pressure differences across the compressor, which are built up by the compressor; typically the synthesis cycle gas is delivered at a pressure of about 170 bar to about 300 bar, in particular from 190 bar to 210 bar. Consequently, the

The compressor has a suction side and a pressure side. The suction side takes in

Compressor absorbs the gas mixture from the ammonia synthesis cycle and releases it back to the ammonia synthesis cycle via the pressure side. For this purpose, the inlet of the converter is fluidically connected to the pressure side of the compressor and the outlet of the converter is fluidically connected to the suction side of the compressor. "Flow-connected" means that there is a connection through which a fluid medium such as a gas or liquid can flow (here between the

pressure side of the compressor and the inlet of the converter or the

Outlet of the converter and the suction side of the compressor), whereby this does not exclude the possibility of further functional elements being located within the flow-through section (conveying section), including those by means of which this connection

Can be diverted or otherwise regulated or even blocked.

Downstream of the converter (the terms “downstream” and “upstream” refer to the synthesis cycle direction in the ammonia synthesis cycle, i.e. the

Conveying direction of the gas mixture within the ammonia synthesis cycle), during production operation - especially during operation at full load, i.e. at a capacity of 100% - ammonia is removed from the ammonia synthesis cycle in an ammonia separator (typically cryogenically in a refrigeration system, for example an ammonia refrigeration system, in which the gas mixture is cooled, whereby ammonia condenses out in liquid form and can be separated from the gas stream, but in principle other partially selective processes for

Gas separation is possible, for example a pressure swing adsorption / “Pressure

Swing adsorption or separation using selectively permeable membranes).

Due to the flow-through process, often only a portion of the ammonia is removed from the ammonia synthesis cycle in the ammonia separator, leaving a certain residual portion in the synthesis cycle gas. Downstream of or in the ammonia separator, reactants (particularly hydrogen and nitrogen) are added to the gas stream in the ammonia synthesis cycle (as fresh gas) before the gas stream is reintroduced into the converter. 230627P00LU

In addition to the feed, the conveyor, the converter and the

Ammonia separator, the ammonia synthesis cycle can have further functional

elements, such as cooling devices for cooling the gas mixture after it has been heated as a result of the heat produced during the reaction (in particular

cooler, heat recovery steam generator or steam superheater), heating devices to

Heating the gas mixture upstream of the converter to a temperature required to ensure the conversion of the reactants to the product ammonia in the converter (in particular electrical heating devices) and/or combined heating/cooling devices to use excess thermal energy of the gas mixture after leaving the converter to heat the gas mixture before it enters the converter (in particular gas-gas heat exchangers).

The fresh gas, which is fed into the ammonia synthesis cycle (backend), is provided in the ammonia synthesis plant by a synthesis gas generation device (frontend) via the feed as synthesis gas, i.e. as a gas mixture which is used for the synthesis of ammonia and which mainly contains nitrogen and

Contains hydrogen. In the synthesis gas generation device, the synthesis gas is produced from three different reactant gases: a hydrocarbon-containing reactant gas, an oxidant, and water. These gases are fed into a reformer, where they react with each other. Depending on the reaction regime, different processes can take place in the reformer.

In steam reforming, hydrocarbons are catalytically converted with steam in an endothermic process allothermically (or autothermally) to

reaction, typically at temperatures of about 700 °C to 900 °C and a pressure of about 25 bar to 80 bar, while in a partial oxidation

Hydrocarbons are reacted thermally or catalytically in an exothermic process with a deficit of oxygen, in both cases producing molecular hydrogen. In autothermal reforming,

Steam reforming and partial oxidation are combined so that part of the

Hydrocarbons are oxidized substoichiometrically and the resulting heat is used for steam reforming. Carbon monoxide produced during reforming can be used as part of a carbon oxide

Conversion (carbon oxide conversion, carbon monoxide conversion, water gas

Shift reaction) with water to form carbon dioxide and hydrogen, thereby increasing the hydrogen yield. In this case, this is an autothermal reforming process.

During reforming, depending on the origin of the hydrocarbon-containing reactant gas, a pre-reforming treatment or a post-treatment of the reformed gas mixture obtained during reforming may be required before autothermal reforming, for example hydrogenation (hydrogenation) for hydrocarbon-containing reactant gases with a high content of unsaturated

Compounds and/or pre-desulfurization for hydrocarbon-containing

Educt gases with high sulfur content (typically this is done catalytically in a defined temperature range typically from about 320 °C to about 400 °C, so that part of the preheating - including heating with the fired

burner device - can also be carried out before the pre-desulfurization). In

In addition to carbon oxide conversion, measures are usually taken during post-treatment to reduce the oxygen content of the synthesis gas (reformed gas mixture), since even traces of oxygen can impair the activity of the catalyst or even damage it during the downstream reaction of the synthesis gas to ammonia.

Carbon dioxide obtained from carbon oxide conversion is removed from the reformed gas mixture, for example by means of a basic carbon dioxide scrubber or a

Methanol wash, remaining traces of carbon monoxide and carbon dioxide in a

Methanizer is converted to methane as part of a methanation process and any

Residual moisture is removed by drying, for example with the help of suitable

Molecular sieves. Furthermore, it is possible to add water in the

ammonia synthesis cycle; If the reformed gas mixture is fed into the

If the ammonia synthesis cycle is fed upstream of the ammonia separator, the water contained in the reformed gas mixture can also be cryogenically separated from the synthesis cycle gas.

Any gas containing hydrocarbons can be used as the reactant gas which

Contains hydrocarbons and is suitable for autothermal reforming, i.e., in particular (natural) natural gas and/or synthetic gas mixtures similar to natural gas. Natural gas is a gas mixture that mostly consists of methane. Depending on its origin, it may contain other long-chain components, such as ethane, propane, butane, ethylene, pentane, and other 230627P00LU

Components such as water, hydrogen sulfide and organic

Sulphur compounds, nitrogen, carbon dioxide and noble gases. Examples of

Gas mixtures that are similar to natural gas include synthetic natural gas (SNG) and non-synthetic biogas.

The oxidant is typically an air-based reactant gas, i.e., a gas that contains atmospheric oxygen as the oxidant. Instead of air, another oxidant can also be used. This was demonstrated in the presentation "Decarbonize with blue ammonia" by Ameet Kakoti and Per Juul Dahl, which was presented on September 13, 2022, at the 66th Annual

Safety in Ammonia Plants and Related Facilities Symposium of the AIChE in Chicago, a process for producing ammonia was described in which the synthesis gas is generated in an autothermal reformer. Pure oxygen, obtained from a cryogenic air separation unit, is used as the oxidant for the autothermal reforming. This air separation unit also produces pure nitrogen, which is mixed with the synthesis gas before being fed into the ammonia synthesis cycle. An advantage of this reaction procedure is that the synthesis cycle gas contains only small amounts of inert gases such as argon or methane, so that purging is rarely necessary, which results in a

Ammonia production, the circulation amount of synthesis cycle gas and thus also the

The total amount of oxygen used in the autothermal

The amount of oxygen required for reforming is obtained by the air separation plant, which is why the air separation plant must have a relatively high capacity for this reaction, which is associated with high costs. Since nitrogen can be considered a chemically inert component in reforming, the use of pure oxygen is not mandatory. There are also other processes in which

The oxidizing agent used is air, which is enriched with oxygen;

The use of oxygen-enriched air is preferred here. This makes it possible to significantly reduce the costs of constructing the air separation plant, since the plant then only needs to be designed for the amount of oxygen with which the air is to be enriched. The required amount of oxygen is determined by first calculating the amount of air based on the amount of oxygen required for ammonia production.

The amount of nitrogen is determined and the required for the respective plant

The amount of oxygen is calculated from the heat demand of the plant and other factors 230627P00LU (for example, the ratio of sulfur to oxygen in the hydrocarbon-containing feed gas or the target carbon dioxide emission).

Difference between the required amount of oxygen and the amount specified in the

The oxygen contained in the air must be added in the form of (pure) oxygen. A vapor-containing reactant gas is used as steam, i.e., a gas mixture containing water vapor, or even pure water vapor; this can, for example, be generated in advance in a steam boiler or saturator, to which water is added in liquid form. Accordingly, the three reactant gases—an air-based reactant gas, a vapor-containing reactant gas, and a hydrocarbon-containing reactant gas—are provided. These can each be provided individually or as

Gas mixtures in which two or more of these reactant gases are provided together. It is also possible that one of these reactant gases is provided by another, for example, by passing the hydrocarbon-containing reactant gas through liquid water in a saturator and, on its way through the water,

absorbs moisture in the form of vapor, whereby the resulting gas mixture is both the hydrocarbon-containing reactant gas and the vapor-containing reactant gas.

Depending on the specific process, in addition to the three reactant gases, other

Educt gases are used, for example as a fourth educt gas or as a further

Educt gases. The educt gases are typically provided in compressed form or compressed during the process.

The second step of the ammonia production process involves

Heating at least one of the three reactant gases with a fired

Burner device, wherein at least one heated reactant gas is obtained. For example, the hydrocarbon-containing reactant gas can be heated, or the steam-containing reactant gas or the air-based reactant gas or two of the aforementioned

Educt gases, for example the hydrocarbon-containing educt gas and the steam-containing

reactant gas, or all three reactant gases. The fired burner device is a fired

Burner, i.e. a device to which a liquid or gaseous fuel is fed, which is burned with flame formation and thereby releases thermal energy zo (heat). With the help of such a fired burner device, the

outside of a pipe or container in which the material to be heated is

Educt gas is located or through which it flows, whereby the educt gas absorbs the thermal energy via the wall of the pipe or container and is heated. 230627P00LU In the fired burner device, the fuel gas does not come into direct contact with the educt stream, but only into thermal contact.

Preheating in the autothermal process, which uses the fired

burner device differs significantly from the conventional

Steam reforming, since in the latter case not only the feed lines of the inlet streams are heated, but the reformer itself is arranged in a furnace box (combustion chamber, fire box) and is thus directly fired, whereby the heat transfer from the

The heat transfer from the furnace box to the reformer is usually done via radiation. Unlike the classic

In steam reforming, a separate firing of the reformer is not required in an autothermal reaction, since the required heat energy is generated by the ongoing reaction itself. In autothermal reforming, such a fired burner device is primarily used to heat the reactant gases (or at least one of them); in addition, the heat generated by the fired

The heat generated by the burner device can also be used separately to heat other process streams, for example boiler feedwater and steam. If the fired burner device is used to heat more than one reactant gas, the respective reactant gas streams are either mixed with each other before they reach the fired burner device (they are therefore in the same pipeline during heating) or they reach the fired burner device in different pipelines and are consequently

The reactant gas streams are mixed together either in the burner or downstream of the burner. Furthermore, it is also possible for the reactant gas streams to be mixed together in the autothermal reformer. The heating must take place before the reactants enter the actual

Reformers are initiated.

In the third step of the process, at least one heated reactant gas and the remaining three reactant gases are fed into an autothermal reformer. Two or all three reactant gases can be combined to form a common

Educt gas stream, which is then fed into the autothermal reformer as a common educt gas stream, or can be fed individually into the autothermal reformer. Feeding can be done in any way, for example, as a radial

Feed or via several ring-shaped inlet nozzles, the latter providing better heat distribution with less volume participation and thus defined 230627P00LU

Reaction conditions are possible. If more than one reactant gas has been heated, then more than one heated reactant gas is fed into the autothermal reformer.

In the fourth step, the three feed gases are autothermally reformed, i.e. they are subjected to an autothermal reaction in the autothermal reformer.

A reformed gas mixture is obtained whose total hydrogen content is higher and whose total content of hydrocarbons as well as water (steam) and oxygen is lower than that of the gas mixture before autothermal reforming.

For autothermal reforming, all common and suitable

Processes are considered as long as the reaction is carried out autothermally (in an autothermal reaction, an exothermic and an endothermic reaction take place).

reaction takes place in parallel, so that the resulting exothermic reaction

Reaction heat can be used for the endothermic reaction without the

The entire process requires further external heat input). Such an autothermal reaction differs fundamentally from an allothermal

Reaction procedure in which an external heat supply is required to carry out an endothermic reaction; the latter, for example, in a

Steam reforming. The reformer can be designed as a single-stage or multi-stage autothermal reformer, optionally with a heat exchanger between the reformer stages to cool the reformed or partially reformed gas mixture.

In the fifth step, the reformed gas mixture is fed into an ammonia synthesis cycle with a synthesis cycle gas. The reformed gas mixture is mixed with the synthesis cycle gas, typically in any of the

Elements of the ammonia synthesis cycle can take place, for example in the

Converter, in the separation, in the compressor, in the ammonia separator or in any other elements, for example in heat exchangers on or in

Pipelines through which the functional elements are connected.

Feeding into the synthesis cycle, which in the synthesis cycle direction after the

Reacting in the converter but before removing ammonia from the

Synthesis cycle gas (i.e. at a point between the converter and the ammonia separator, i.e. downstream of the converter and upstream of the ammonia separator in the flow direction) offers the advantage that part of the cooling of the synthesis cycle gas required for cryogenic separation of ammonia

synthesis cycle gas is effected by supplying the fresh gas, at the same time 230627P00LU any residual amounts of vaporous water which may be present in the reformed

gas mixture (for example as a reaction product of methanation in a methanizer during processing), together with the ammonia, are removed from the reformed gas mixture before it is introduced into the converter

Is. Feeding into the synthesis cycle, which takes place in the synthesis cycle direction after the removal of ammonia from the synthesis cycle gas (i.e. at a point between the ammonia separator and the converter, i.e. downstream of the ammonia separator and upstream of the converter in the flow direction), offers the

The advantage is that the amount of gas that is released upstream from the

Ammonia separator must be cooled and reheated upstream of the ammonia separator.

If the feed is made in the pipelines, a

A connecting piece is used, for example a T-shaped connecting piece (pipe connection) or a Y-shaped connecting piece. Alternatively, a separate mixing chamber can be used to introduce the reformed gas mixture into the

Synthesis cycle gas is intended for this purpose.

The reformed gas mixture fed into the ammonia synthesis cycle is used as fresh gas, replacing the reactant gases consumed during the reaction, so that during production operation the synthesis cycle gas enters the

Converter in each pass of the ammonia synthesis cycle can have an at least substantially similar composition. Typical composition for the reformed gas mixture fed in is, for example, from about 65 vol.% to about 80 vol.% hydrogen, from about 20 vol.% to about 30 vol.% nitrogen, from 0 vol.% to about 5 vol.% methane, from 0 vol.% to about 2 vol.% argon and traces of

Carbon monoxide, carbon dioxide and water, with the proportions adding up to 100 vol%.

In the sixth step, the synthesis cycle gas is converted in a converter, where

Ammonia is produced in the synthesis cycle gas. In principle, any suitable reaction and corresponding reaction conditions can be selected for this purpose, but a Haber-Bosch process is often used. In this process, elemental hydrogen reacts with elemental nitrogen in a catalytic

Equilibrium reaction with formation of ammonia, where hydrogen and nitrogen do not react completely to form ammonia, which is why the reaction procedure is a 230627P00LU

recirculation of the synthesis cycle gas, typically after the largest

Part of the ammonia is separated from the synthesis cycle gas (this happens in the

Production operation; in a partial load operation or in a so-called “hot

In "hot stand-by" mode, ammonia separation can be omitted in order to allow the cycle gas to circulate in the ammonia synthesis cycle without net conversion, so that the temperatures required for the reaction are maintained and no lengthy heating-up is required when transitioning to production mode or to full-load operation.

In the seventh step, the synthesis cycle gas is split into a first substream and a second substream. The first substream is quantitatively smaller than the second substream; typically, a first substream of about 5 vol.% to 12 vol.% of the total synthesis cycle gas stream is separated, typically about 10 vol.%, so that (when split into only two substreams) a second

Partial stream of approximately 88 vol.% to 95 vol.% of the total synthesis cycle gas stream

In the ammonia synthesis cycle, typically about 90 vol.% remains. In principle, this split can take place anywhere within the ammonia synthesis cycle, for example downstream of the converter and upstream of the feed or downstream of the converter and upstream of the ammonia separation, depending on

However, the division can also be carried out at all other positions of the ammonia synthesis cycle, for example downstream of the feed and upstream of the converter, downstream of the feed and upstream of the compressor, downstream of the

Ammonia separation and upstream of the feed, downstream of the

Ammonia separation and upstream of the converter, downstream of the

Ammonia separation and upstream of the compressor, downstream of the

Compressor and upstream of the converter and the like, each arrangement having certain advantages and disadvantages.

During the splitting (including separation), a partial flow from the

Synthesis cycle gas is branched off and removed from the ammonia synthesis cycle. zo Of course, it is also possible to branch off more than one partial stream from the synthesis cycle gas, if necessary at different positions of the

synthesis cycle, for example a partial flow downstream of the converter and upstream of the feed, another partial flow downstream of the 230627P00LU

Ammonia separation and upstream of the feed. It is possible to divide the synthesis cycle gas into just two partial streams or into more than two partial streams, for example three or four partial streams, which can be used for different purposes (these can therefore be used as

Fuel gas can be fed to the fired burner device or fed back to the converter for recirculation. In addition, other uses are also possible, such as introducing the diverted partial flow into a storage tank - for example, to create a reserve that is only fed back into the ammonia synthesis cycle at a later time - or feeding the diverted

partial stream to another chemical plant where the composition is used as a reactant, possibly after prior processing).

Synthesis cycle gas is divided into more than two partial streams, then these can be

Depending on the flow direction of the respective partial stream downstream of the branch, it can be separated, recombined or forwarded separately. In these cases, it is possible that the separate partial streams have different

Post-processing; for example, it is possible that the

The partial streams discharged from the synthesis cycle gas or the partial stream continued as synthesis cycle gas can be cooled differently using different heat exchangers and/or used to preheat other gas streams. Since the synthesis cycle gas is cooled at different positions within the

Since the ammonia synthesis cycle can have different compositions as well as different pressures and temperatures, by splitting off several partial streams a branched synthesis cycle gas can be obtained which is particularly suitable for the desired purpose.

The branching can be regulated or unregulated, for example via simple connecting pieces such as T-shaped connecting pieces or Y-shaped connecting pieces, which are designed to be open throughout or can be locked with appropriate closure means, for example with

valves or the like. Typically, such a portion of the gas stream is branched off as purge gas (normally from about 5 vol.% to about 15 vol.%, typically about 8 vol.%, of the ammonia synthesis cycle circulating gas).

synthesis cycle gas stream, so that about 85 vol.% to about 95 vol.%, typically about 92 vol.%, of the synthesis cycle gas remains in the ammonia synthesis cycle), 230627P00LU to prevent inert components of the synthesis cycle gas from accumulating there during repeated passage through the ammonia synthesis cycle and the

Influence the reaction process (for example, argon, which is present in the reformed

gas mixture if nitrogen is not supplied as a pure gas — for example, obtained from pressure swing adsorption — but in the form of air, which contains almost 1 vol% argon). In a simple conventional

In the process, the vent gas is diverted from the ammonia synthesis cycle and released into the atmosphere either diluted or undiluted. In addition, improved conventional processes exist in which the load on the

The environmental impact is reduced by first burning the exhaust gas (for example, flaring it, for example at the flare head of a chimney-like pipe on which a burner is arranged) before the resulting flue gas is released into the

atmosphere. In an allothermal process, for example in a steam reformer, the gas produced in a conventional process can

Heat generated by post-combustion in a furnace box can be used to directly heat the reformer and maintain the endothermic reforming.

This is not provided for in the method according to the invention. Instead, the first

Partial flow of the fired burner device is fed as hydrogen-containing fuel gas.

This means that the diverted exhaust gas is used to operate a burner that is located in the

The hydrogen contained in the synthesis cycle gas — typically from about 45 vol.% to about 60 vol.% — serves as fuel, through the combustion of which the burner of the fired burner device preheats at least one of the three reactant gases before feeding it into the autothermal reformer. Since the hydrogen is required in the vent gas, in contrast to conventional processes, the present process requires a

Hydrogen recovery from the vent gas (for example using

membrane technology) is therefore not particularly sensible. In addition, any

The methane contained in the synthesis cycle gas is also used as a fuel (although this results in the formation and release of small amounts of carbon dioxide).

In this way, it is possible to operate the fired burner device with a fuel gas that does not contain hydrocarbons (or at most traces of them), so that an additional emission of carbon dioxide into the atmosphere due to the

Firing can be avoided by means of the fired burner device. It is advantageous if the first partial stream, after separation from the second partial stream 230627P00LU, is first subjected to ammonia separation, for example in a

In this way, the target product is also obtained from the first partial flow

Ammonia is extracted, while at the same time preventing ammonia from being released into the atmosphere with the exhaust gas from the fired burner device. This amount can be significantly reduced if the first partial stream is separated from the synthesis cycle gas downstream of the ammonia separator and upstream of the converter, since the synthesis cycle gas there contains only a small amount of ammonia - and consequently also the first partial stream branched off from it at this point. Preferably, such a proportion of the synthesis cycle gas is separated as the first partial stream that the hydrogen it contains is sufficient to operate the fired burner device without additional fuel. If this is not practical or possible, additional synthesis gas, which also contains hydrogen, can be taken from the

Synthesis gas generation equipment can be diverted and fed to the fired burner to supplement the first partial flow of fuel gas. In principle, it is also possible to replace any missing fuel in the fuel gas with a hydrocarbon-containing fuel gas; however, this is disadvantageous because it results in the formation and release of additional carbon dioxide. However, the amount of carbon dioxide released is significantly lower than when using a hydrocarbon-based fuel gas such as methane alone.

In an advantageous embodiment of the method according to the invention, it is provided in particular that it further comprises the steps h) returning the second

partial flow for feeding the reformed gas mixture and i) removing

Ammonia from the synthesis cycle gas. By recycling the second

Partial flow for feeding the reformed gas mixture, a part of the

Synthesis cycle gas downstream from the converter back to the inlet of the

converter (and thus to a position upstream of the converter) and undergoes another conversion, creating a real

At the same time, ammonia is extracted from the

Synthesis cycle gas is removed — for economic reasons, this is often done as part of a (fractional) separation in a refrigeration plant, typically a

Ammonia refrigeration system, which uses ammonia as a refrigerant, but other systems for separating gases can also be used, for example a

Pressure swing adsorption to achieve more than one 230627P00LU

component of the cycle gas. By separating ammonia from the synthesis cycle gas before it re-enters the converter, a

A composition is obtained which does not correspond to the equilibrium composition existing at the respective pressure and temperature, so that when the mixture passes through the converter again, a corresponding amount of ammonia is formed and the overall ammonia yield is increased; this configuration is particularly advantageous in the context of a Haber-Bosch process.

In a further advantageous embodiment of the method according to the invention, it is particularly provided that the air-based reactant gas is air which is

was enriched with oxygen, in particular with oxygen from air separation.

A total proportion of oxygen in the enriched air from a

Range of about 20 vol% to about 50 vol%, particularly preferably from a range of about 35 vol% to about 48 vol%. In contrast to the regular

Unlike steam reforming, which uses air as the oxidant, autothermal reforming typically uses pure oxygen as the oxidant. This has the disadvantage that autothermal reforming requires a separate plant to produce pure oxygen. In the present case, however, synthesis gas production using autothermal reforming can also be

Use air that has been enriched with oxygen. Here, too, the oxygen is typically supplied from a suitable system for providing pure

Oxygen is obtained, for example, from a cryogenic air separation plant, a

Pressure swing adsorption plant or a membrane plant, but it can also come from a tank or the pipeline of an oxygen supply system. However, since in this embodiment of the present process the required oxidant does not consist entirely of pure oxygen and the purified oxygen represents only a part of the total oxidant, it is possible to reduce the capacity of such a plant for providing pure oxygen compared to the capacity of conventional plants, typically to about one third of the otherwise required capacity. In a further advantageous embodiment of the process according to the invention, it is provided in particular that the reformed gas mixture is additionally

Feeding into the synthesis cycle gas is subjected to a carbon oxide conversion in which carbon monoxide reacts to carbon dioxide, followed by a 230627P00LU

Carbon dioxide separation, in which carbon dioxide is removed from the reformed gas mixture, followed by methanation, in which carbon oxides in the reformed gas mixture are converted into methane. Especially when using the Haber-Bosch process, it is important to remove all oxygen-containing compounds from the reformed gas mixture - especially oxygen, water, carbon monoxide and

Carbon dioxide - because the activity of the substances used in this process

Catalysts decrease upon contact with oxygen-containing compounds. In autothermal reforming, the ratio of hydrocarbons to oxygen is typically chosen substoichiometrically, since the hydrocarbons are not intended to be completely oxidized; rather, hydrogen is to be produced.

This ensures that the reformed

Gas mixture no longer contains molecular oxygen. In the carbon oxide

Conversion (water gas conversion reaction, water gas shift reaction) then carbon monoxide reacts (possibly in several stages) with the gas mixture

Water vapor to carbon dioxide and hydrogen, thereby reducing the carbon monoxide content in the reformed gas mixture and simultaneously increasing the hydrogen content.

At least a portion of the water contained in the gas mixture can be separated as process condensate. The carbon dioxide obtained during carbon oxide conversion, as well as the carbon dioxide already present in the gas mixture, is separated from the reformed gas mixture, typically using a scrubber, such as a gas scrubber with an alkaline aqueous scrubbing liquid or a neutral aqueous scrubbing liquid, optionally also with alkaline organic solvents.

Washing liquids or other suitable washing liquids.

The process control for carbon oxide conversion is usually chosen so that the

Carbon monoxide is converted as completely (quantitatively) as possible to carbon dioxide, and the process for carbon dioxide separation is usually chosen so that the

Carbon dioxide is separated as completely as possible from the reformed gas mixture, whereby a scrubbing liquid loaded with carbon dioxide is obtained (in this

Scrub liquid may also contain water from the reformed gas mixture, which is produced as process condensate during carbon dioxide separation if it has not been separated separately beforehand. In practice, however, it is unavoidable that small traces of carbon monoxide and carbon dioxide still enter the

ammonia synthesis cycle, but depending on the catalyst material, these must not exceed a certain limit, typically a maximum of 20 ppm 230627P00LU

Oxygen from oxygen-containing molecules. To reduce the proportion of traces of

To reduce carbon monoxide and carbon dioxide, the reformed gas mixture freed from carbon dioxide is additionally subjected to methanation in a methanizer (methanation device, methanation), in which the carbon monoxide and carbon dioxide not removed from the reformed gas mixture react with hydrogen and are converted to methane and water.

The water that accumulates in the gas mixture must also be removed, which can be done, for example, by drying with suitable adsorbents (molecular sieves, molecular sieves) or by condensation (e.g. in a refrigeration system such as a

Ammonia refrigeration system, for which an ammonia separator arranged in the ammonia synthesis circuit can be used, provided that the reformed

Gas mixture is fed into the ammonia synthesis cycle in such a way that the

Synthesis cycle gas first passes through the ammonia separator after being fed in before it reaches the converter, i.e. downstream of the

converter and upstream of the ammonia separator). The methane obtained during methanation behaves in the subsequent conversion in the

Ammonia synthesis cycle as an inert gas and can therefore be used as a component of the reformed

Gas mixture is fed into the ammonia synthesis cycle.

As a rule, the washing liquid loaded with carbon dioxide is processed and

Carbon dioxide is removed so that the washing liquid can be reused.

Carbon dioxide can be made available as a raw material for further processes, for example for carbonating drinks for the beverage industry (since the origin of the gas offers an extremely high purity in food quality), so that this carbon dioxide is ultimately released into the atmosphere, but the release does not occur immediately, but the carbon dioxide is used as a raw material beforehand (so that this carbon dioxide does not have to be produced elsewhere).

After its use elsewhere, this carbon dioxide would be released anyway, so this process would not result in the emission of additional

carbon dioxide, but only from carbon dioxide that would be released into the atmosphere anyway. In order to use the separated carbon dioxide as a raw material for further

To provide procedures, it is usually a

carbon dioxide pipeline system. In addition, the carbon dioxide 230627P00LU can be subjected to further processes after separation, for example

Compression in a compressor.

Advantageously, it can additionally be provided that the carbon dioxide removed from the reformed gas mixture is fed into a carbon dioxide storage facility. This can be any system suitable for the temporary or permanent physical or chemical storage of compressed carbon dioxide, for example a storage tank or a storage system in which carbon dioxide sequestration is implemented according to the concept of "Carbon Capture and Storage" (CCS) technology, in which the stored carbon dioxide is stored underground. In the latter CCS storage system, at least a portion of the carbon dioxide that would otherwise be released into the atmosphere is stored, which is why this

How “blue” ammonia can be produced.

In a further advantageous embodiment of the method according to the invention, it is provided in particular that the reformed gas mixture is additionally divided into two partial streams before being fed into the synthesis cycle gas, one of which is fed into the synthesis cycle gas and the other

Partial flow of the fired burner device in addition to the first partial flow from the

Synthesis cycle gas is supplied as hydrogen-containing fuel gas, wherein in particular the hydrogen-containing fuel gas of the fired burner device consists of the first partial flow of the synthesis cycle gas and the partial flow of the reformed gas mixture. Accordingly, a partial flow of the reformed

Gas mixture, which is actually intended for feeding into the

Ammonia synthesis cycle is separated before feeding and fed to the burner in addition to the partial stream which is separated from the synthesis cycle gas. This is particularly advantageous if the partial stream discharged to discharge the inert components of the synthesis cycle gas is not sufficient as fuel gas to operate the fired burner device without additional fuel gas. In this case, the missing fuel gas quantity can be replaced by the reformed

gas mixture which has a relatively high hydrogen content zo. This makes it neither necessary to add additional fuel gas to the

ammonia synthesis cycle (which also results in a certain

Amount of ammonia would be removed), nor is it necessary to use additional fuel gas in the form of hydrocarbon-containing compounds. In this way, the ammonia yield can be increased without releasing significant amounts of additional carbon dioxide into the environment.

In a further advantageous embodiment of the process according to the invention, it is particularly provided that the hydrocarbon-containing reactant gas is additionally pre-reformed before being fed into the autothermal reformer. This typically takes place in a reaction with steam, which is added to the hydrocarbon-containing

Educt gas is added as steam-containing educt gas in a pre-reformer or even before entering the pre-reformer. Pre-reforming is a process that precedes the actual autothermal reforming and in which higher

Hydrocarbon components of the hydrocarbon-containing reactant gas, in particular long-chain hydrocarbons and/or cyclic hydrocarbons therein, after addition of steam under relatively mild conditions into methane,

Carbon dioxide, carbon monoxide and hydrogen to avoid the deposition of coke and carbonaceous residues during preheating of the hydrocarbon-containing educt gas as well as during entry into the autothermal reformer and exit from the autothermal reformer. Typically, a catalyst is used for this purpose.

Use, for example, a catalyst containing nickel. This not only reduces the load on the autothermal reformer, but can also

Reforming reduces the steam-to-carbon ratio and increases the preheating temperature. Furthermore, pre-reforming allows the use of different raw materials from different sources.

In addition to the previously described

Embodiments naturally also comprise the process measures described below in connection with the ammonia synthesis plant according to the invention, in particular insofar as these result from the structural design of the ammonia synthesis plant.

The above-mentioned object is also achieved by an ammonia synthesis plant, in particular for carrying out the above-mentioned process.

In addition to the structural configurations described below, the ammonia synthesis plant can, of course, also have the structural configurations described in connection with the process according to the invention, in particular insofar as these result from the process. 230627P00LU

This is an ammonia synthesis plant with a

Synthesis gas generation device for generating a reformed gas mixture using three reactant gases, namely a hydrocarbon-containing reactant gas, an air-based reactant gas and a steam-containing reactant gas, a

Ammonia synthesis cycle for producing ammonia in a

synthesis cycle gas conveyed in the synthesis cycle direction and a feed for feeding the reformed gas mixture into the synthesis cycle gas. The

The synthesis gas generation device and the ammonia synthesis cycle are fluidically connected via the feed. The 11 synthesis gas generation device has an autothermal reformer for generating the reformed gas mixture using the three reactant gases and a

Gas heater for heating at least one of the three reactant gases before feeding it into the autothermal reformer. The gas heater has a burner device fired with a fuel gas. The ammonia synthesis cycle has a converter for generating ammonia in the synthesis cycle gas and a

Separation for separating the synthesis cycle gas into a first partial stream and a second partial stream. The separation is connected to a discharge line for discharging the first partial stream. According to the invention, the discharge line of the separation is fluidically connected to the fired burner device for supplying the first partial stream as fuel gas to the fired burner device.

A synthesis gas generation device is a part of the plant in which a

Synthesis gas is produced, i.e. a gas mixture that is used for synthesis.

In this case, the synthesis gas is used for the synthesis of ammonia.

As a result, a gas mixture (the reformed gas mixture) is produced in the synthesis gas generation device, which has nitrogen and

As previously described, the reformed gas mixture is made up of three

Educt gases are generated, the hydrocarbon-containing educt gas, the air-based

reactant gas and the vapor-containing reactant gas.

The essential functional element of the synthesis gas generation device is an autothermal reformer for generating the reformed gas mixture using the three reactant gases. This autothermal reformer can basically be designed in any way, for example as a single-stage or multi-stage autothermal reformer, in which the introduction of the three reactant gases can take place individually or jointly, for example via a single nozzle, for example in an axial arrangement in a ceiling section of the

reformer wall, or via several nozzles, for example in a radial-circular

Arrangement on the Reformer wall. Furthermore, the

Synthesis gas generation device a gas heater with a fired

Burner device that can be operated with a fuel gas, i.e. a combustible

Gas which is suitable as a starting material for combustion reactions. With the help of the fired burner device of the gas heater, at least one of the three

Educt gases are heated before being fed into the autothermal reformer without the

Burner exhaust gases come into direct contact with the reactant gases. Typically, the fired burner device is located within the gas heater and the reactant gases are individually or mixed with each other spatially separated from the fired

Burner device passed separately past this, for example within

Pipes separated by the pipe wall or within a separate room separated by partition walls, for example plate walls. In the fired burner device ı5 the fuel gas is burned and the generated heat energy preheats at least one reactant gas. In addition, the

Synthesis gas generation device naturally contains other elements such as piping, shut-off elements such as valves and measuring devices for

Monitoring of the process flow or other functional elements such as a hydrogenation upstream of the autothermal reformer, a sulfur separation upstream of the autothermal reformer, a

Reformer downstream carbon dioxide converters, a carbon dioxide separation or a methanizer downstream of the carbon dioxide separation, gas drying (e.g. with the help of molecular sieves) as well as heat exchangers and the like.

The synthesis gas generation device and the ammonia synthesis circuit are fluidically connected via the feed. Any device used to introduce a gas from one part of the plant (here the synthesis gas generation device) into another part of the plant (here the

ammonia synthesis circuit), for example a mixing room (which is located in the ammonia synthesis circuit and which may contain mixing elements for

Mixing of the supplied gas streams, wherein the

Synthesis cycle gas can flow through it and this additionally

introduction of the reformed gas mixture) or a three-way 230627P00LU

Pipe connection, for example a T-shaped connector or a Y-shaped

The inlet can also be used as part of a functional

Element of the ammonia synthesis cycle, for example the

compressor, converter or ammonia separator, so that the introduction takes place within this functional element.

As already described, the ammonia synthesis cycle has the converter as an essential functional element, through which the synthesis cycle gas in the

Synthesis cycle direction is cyclically passed through with the help of a compressor.

This can be designed as desired, for example single-stage or multi-stage, such as two-stage, three-stage or four-stage, whereby the different stages can be housed in different housings or in the same housing (the different stages can be connected fluidically one after the other or in parallel). Between individual stages, additional elements such as heat exchangers can be provided to dissipate heat energy generated during the reaction. Downstream of the compressor (which in a circuit also means upstream of the compressor), the

Ammonia synthesis cycle has an ammonia separator (typically under

Use of a refrigeration system, for example an ammonia refrigeration system). In addition to the

In addition to the feed, the conveyor, the converter and the ammonia separator, the ammonia synthesis cycle can include further functional elements, such as

Cooling devices for cooling the gas mixture after it has been heated as a result of the

reaction was heated (especially coolers,

Waste heat steam generators or steam superheaters), heating devices to heat the gas mixture upstream of the converter to a temperature required to ensure the conversion of the reactants to the product ammonia in the converter (in particular electrical heating devices) and/or combined heating/cooling devices to use excess thermal energy of the gas mixture after leaving the converter to heat the gas mixture before entering the converter (in particular gas-gas heat exchangers). In addition, the ammonia synthesis cycle has a separation for separating the

synthesis cycle gas into a first partial stream and a second partial stream. The

Separation can be carried out in any way, whereby the first partial flow and the second

Partial flow can be diverted away from each other. The separation can be designed, for example, as a 230627P00LU separate separation chamber, if necessary with flow guide elements to deflect the gas flow in the desired direction, or as

Three-way pipe connection, for example, a T-shaped connector or a Y-shaped connector. The separator can also be designed as part of another functional element, for example, the compressor, the converter, or the ammonia separator. The separator is connected to a drain line to

The discharge line of the separation is connected to the fired

Burner device connected, whereby the first partial flow is used as fuel gas of the fired

Burner device can be fed.

In an advantageous embodiment of the ammonia synthesis plant according to the invention, it is provided in particular that the synthesis gas generation device further comprises at least three reactant gas feeds, namely a

Hydrocarbon feed to provide the hydrocarbon-containing

reactant gas, an oxidant supply to provide the air-based

reactant gas and a steam supply for providing the steam-containing reactant gas, wherein the gas heater is fluidically connected between at least one

reactant gas supply and the autothermal reformer, whereby the fired

Burner device has a fuel gas line for supplying the first partial flow as hydrogen-containing fuel gas, which is fluidically connected to the discharge line, wherein the ammonia synthesis cycle has a compressor for conveying the synthesis cycle gas in the synthesis cycle direction and a

Ammonia separator for removing ammonia from the synthesis cycle gas, wherein the separation is connected in addition to the discharge line to a return line for returning the second partial stream to the feed. The reactant gases are thus fed to the synthesis gas generation device through at least three

Educt gas feeds are provided, in addition, further

Educt gas feeds may be provided. For example, it is possible to

Feeding of educt gas via several educt gas feeds, for example, the zo hydrocarbon-containing educt gas can be fed via more than one feed, whereby the same hydrocarbon-containing

Educt gas or another hydrocarbon-containing educt gas can be supplied, so that it is possible to supply different hydrocarbon-containing educt gases 230627P00LU; the same applies to the oxidant supply and the

Steam supply. The reactant gases can be supplied to the synthesis gas generation device separately or mixed with each other, for example by

Educt gas supply for the hydrocarbon-containing educt gas and the steam-containing

Educt gas or for the hydrocarbon-containing educt gas and the air-based

Educt gas or for the air-based educt gas and the vapor-containing educt gas or for all three educt gases flow into a common pipeline before it is

gas heater or the autothermal reformer (or also the

Pre-reformer); typically, the air-based reactant gas is fed to the autothermal reformer alone and, in particular, is neither mixed with the hydrocarbon-containing reactant gas nor with the pre-reformed gas mixture in order to avoid transporting explosive gas mixtures in the pipelines.

With the help of the gas heater, the reactant gases of the respective feed can be heated, whereby at least one of the reactant gases is heated, if necessary two reactant gases or all three reactant gases. If more reactant gases than one

reactant gas, they can be mixed together or heated separately, for example in separate pipelines.

The burner device of the gas heater is typically designed as a gas burner, for example as a hydrogen burner or combined hydrogen-methane burner, and has a fuel gas line via which the fuel gas of the fired

Burner device as fuel. This fuel gas line is fluidically connected to the discharge line, so that the discharge line merges directly or indirectly into the fuel gas line or — in a particularly compact

Arrangement — is identical to this one. In the fuel gas line, the

The oxidizing agent required for the combustion process can be mixed with the fuel gas, but this can also be fed separately into the fired burner device.

In addition to the compressor, which can be designed in any suitable way, for example as

The ammonia synthesis cycle has a return line between the turbocompressor (turbo compressor) and the ammonia separator, which can also be designed in any suitable way, such as a refrigeration system, typically as an ammonia refrigeration system. In the return line, the second partial stream of the synthesis cycle gas, which was separated from the first partial stream in the separation, is returned to the feed (or to a position upstream of the converter) – and thus to the 230627P00LU

converter, which enables the actual recycling of the synthesis cycle gas. By recycling the second partial stream to feed the reformed

Gas mixture, part of the synthesis cycle gas is returned downstream of the converter to the inlet of the converter and again passes through a

Conversion. As a result of the separation of ammonia from the synthesis cycle gas before it re-enters the converter, a composition is obtained which does not correspond to the equilibrium composition at the respective pressure and temperature, so that when it passes through the converter again, a corresponding amount of ammonia is formed, thereby increasing the overall ammonia yield; this design is particularly suitable within the framework of a Haber-

Bosch process is advantageous.

In a further advantageous embodiment of the inventive

Ammonia synthesis plant is particularly intended to further separate the

Synthesis cycle direction downstream of the converter and upstream of the ı5 feed. This design ensures that the reformed gas mixture introduced into the ammonia synthesis cycle before the

Separation first passes through the converter (instead of a portion of the supplied

reactant is already removed from the ammonia synthesis cycle before conversion), so that this reactant continues to be available for the reaction to ammonia

is available (which can then also be separated from the first partial stream, for example in a membrane separation). This increases the ammonia yield.

In a further advantageous embodiment of the inventive

Ammonia synthesis plant, it is particularly intended that the

Synthesis gas generation device an air separation for providing with

oxygen-enriched air as the air-based reactant gas. As already explained, the required oxidant does not consist entirely of pure

Oxygen, the purified oxygen is only a part of the total

oxidizer. This can reduce the capacity of a plant for providing high-purity oxygen, for example, an air separation plant, compared to the capacity of conventional plants. 230627P00LU

In a further advantageous embodiment of the inventive

Ammonia synthesis plant, it is particularly intended that the

Synthesis gas generation device between the autothermal reformer and the

Feeding a carbon oxide converter to convert the carbon monoxide to

Carbon dioxide, a carbon dioxide separation to remove carbon dioxide from the reformed gas mixture and a methanizer to convert

Carbon oxides (i.e. carbon monoxide and carbon dioxide and, where appropriate,

carbon suboxides) in the reformed gas mixture in methane, whereby the

Carbon oxide converter fluidically with the autothermal reformer and the

Carbon dioxide separation is connected, the carbon dioxide separation is fluidically connected to the carbon oxide converter and the methanizer and the

Methanizer is fluidically connected to the carbon dioxide separation and the feed. As already explained, this makes it possible to

Process control is particularly adapted to the requirements of a Haber-Bosch process, in which oxygen components can lead to catalyst deactivation. Advantageously, it can additionally be provided that the carbon dioxide separation is fluidically connected to the carbon dioxide storage for storing the carbon dioxide removed from the reformed gas mixture. The carbon dioxide storage can be any suitable

device or arrangement, for example a storage tank, a

A pipeline through which the carbon dioxide is transferred for another use, or a CCS storage system in which the stored carbon dioxide can be stored underground, for example. This makes it possible to produce "blue" ammonia.

In a further advantageous embodiment of the inventive

Ammonia synthesis plant, it is particularly intended that the

Synthesis gas generation device in the conveying direction of the reformed gas mixture downstream of the autothermal reformer and upstream of the feed

Divider for dividing the reformed gas mixture into two partial streams, wherein the divider comprises a line for feeding one partial stream of the reformed

gas mixture into the synthesis cycle gas, which is fluidly connected to the inlet, and a branch line for supplying the other partial stream of the reformed gas mixture in addition to the first partial stream from the 230627P00LU

Synthesis cycle gas as fuel gas to the fired burner device, wherein the branch line is fluidically connected to the fired burner device. Such a division can basically be carried out in a similar way to the separation for separating the synthesis cycle gas into a first partial stream and a second

Partial flow may be formed or different from it. If the amount of

If the synthesis cycle gas, which is withdrawn from the ammonia synthesis cycle via the discharge line as the first partial stream, is not sufficient to operate the fired burner device, additional fuel gas must be made available; this is usually done by additionally supplying the fired burner device with a hydrocarbon-containing fuel gas to replace the missing amount of fuel gas. As already explained, the withdrawal of reformed gas mixture to replace the missing amount of fuel gas offers the advantage that the amount of gas withdrawn from the ammonia synthesis cycle via the discharge line can be reduced without significantly increasing the amount of carbon dioxide being released into the atmosphere, since the carbon dioxide from the reformed gas mixture also serves as additional

The fuel gas branched off partial stream contains hydrogen as a main component.

In a further advantageous embodiment of the inventive

Ammonia synthesis plant, it is particularly intended that the

Synthesis gas generation device in the conveying direction of the hydrocarbon-containing

reactant gas upstream of the autothermal reformer a pre-reformer to

Pre-reforming of the hydrocarbon-containing feed gas, which is fluidically connected to the autothermal reformer. During pre-reforming, higher hydrocarbon components of the hydrocarbon-containing

reactant gas, especially long-chain hydrocarbons, under relatively mild

conditions into methane, carbon dioxide, carbon monoxide and hydrogen.

As already explained, this allows different raw materials from different sources to be used, coke formation in the

Synthesis gas generation device is prevented and the load of the autothermal

Reformer is reduced, moreover the steam to carbon ratio in autothermal reforming can be reduced and the temperature during preheating can be increased.

Finally, the aforementioned problem is solved by a method for converting an ammonia synthesis plant. This conversion method can, of course, also include the previously described method measures and design configurations in addition to the method measures described below.

In the process for converting an ammonia synthesis plant with a

Synthesis gas generation device for generating a reformed gas mixture using three reactant gases, namely a hydrocarbon-containing reactant gas, an air-based reactant gas and a steam-containing reactant gas, a

Ammonia synthesis cycle for producing ammonia in a

Synthesis cycle gas conveyed in the synthesis cycle direction, as well as with a

Feed for feeding the reformed gas mixture into the

Synthesis cycle gas, wherein the synthesis gas generating device and the

Ammonia synthesis cycle are fluidically connected via the feed, wherein the synthesis gas generation device comprises an autothermal reformer for

Generation of the reformed gas mixture using the three reactant gases and a

Gas heater with a fired burner device for heating at least one of the three reactant gases before feeding into the autothermal reformer, wherein the

Ammonia synthesis cycle a converter to produce ammonia in

synthesis cycle gas, a discharge line is installed that discharges the

Ammonia synthesis cycle with the fired burner device for supplying a discharged partial stream as hydrogen-containing fuel gas to the fired

The installation of such a vent line is equivalent to connecting an existing vent line, such as that used to remove purge gas from the synthesis cycle gas, to the fired

burner device, in particular with the fuel gas line of the fired

Burner device. This provides a particularly simple way to reduce carbon dioxide emissions from an existing ammonia synthesis plant.

In detail, there are numerous possibilities for designing and developing the method and system according to the invention. Reference is made to the claims subordinate to claims 1 and 8, as well as to the following description of preferred

Examples of implementation in conjunction with the drawings, with the help of which the

The invention is explained in more detail below. The schematic drawings show 230627P00LU

Fig. 1 is a schematic representation of a conventional ammonia synthesis plant,

Fig. 2 is a schematic representation of a first embodiment of an ammonia synthesis plant according to the invention,

Fig. 3 is a schematic representation of a second embodiment of an ammonia synthesis plant according to the invention,

Fig. 4 is a schematic representation of a third embodiment of an ammonia synthesis plant according to the invention,

Fig. 5 is a schematic representation of a fourth embodiment of an ammonia synthesis plant according to the invention and

Fig. 6 is a schematic representation of a fifth embodiment of an ammonia synthesis plant according to the invention.

Fig. 1 shows a schematic representation of an ammonia synthesis plant from the

State of the art. The plant comprises a synthesis gas generation device 1 as

Frontend and an ammonia synthesis cycle 3 as backend, both are connected via the

Feed 2. In the synthesis gas generation device 1 there are three feeds for the Edukigase, namely the

Hydrocarbon feed 4 for the hydrocarbon-containing reactant gas, the

Steam supply 7 for the steam-containing reactant gas and the oxidant supply 8 for the air-based reactant gas. From the hydrocarbon supply 4, a

Pipeline, which is connected via a T-shaped connector to a pipeline leading from the steam supply 7, so that the hydrocarbon-containing reactant gas and the steam-containing reactant gas are mixed there, whereby a hydrocarbon-containing steam-containing gas mixture is obtained. The T-shaped connector is fluidically connected to the pre-reformer 13, in which the hydrocarbon-containing steam-containing

The outlet of the pre-reformer 13 is fluidly connected to the gas heater 5, in which the pre-reformed

The gas heater 5 has a fired

Burner device 5.1 with a hydrocarbon burner, to which natural gas is supplied as hydrocarbon-containing fuel gas via the fuel gas line 5.2; the 230627P00LU

Natural gas, which is fed to the fired burner device 5.1, is already mixed with air as the oxidant. The gas heater 5 is fluidically connected to the autothermal reformer 6. Furthermore, the autothermal reformer 6 is connected to the oxidant supply 8, via which the air-based reactant gas is fed to the autothermal reformer 6. The air-based reactant gas is in this

In this case, oxygen-enriched air, namely air that is mixed with pure oxygen, which is obtained from the air separation 18 that is fluidically connected to the oxidant supply 8. In the autothermal reformer 6, the three

Educt gases are reformed in an autothermal reaction. The reformed gas mixture thus obtained is introduced into the carbon oxide converter 9, which is fluidically connected to the autothermal reformer 6. After undergoing a water gas shift reaction in the carbon oxide converter 9, the converted reformed gas mixture is fed to the carbon dioxide separation 10, which is fluidically connected to the carbon oxide converter 9. In the

Carbon dioxide separation 10, carbon dioxide is separated by gas scrubbing and passed on to a carbon dioxide storage 12, which is connected to the carbon dioxide separation 10. The converted reformed gas mixture, freed from carbon dioxide, is introduced into the methanizer 11, where traces of carbon monoxide and

Carbon dioxide is converted into methane. The methanizer 11 is located between the carbon dioxide separation 10 and the feed 2, with which it is fluidly connected.

Via the feed 2, the reformed gas mixture obtained in the synthesis gas generation device 1 (which in this case is the methanized gas from

Carbon dioxide-free converted reformed gas mixture) as fresh gas to the

Synthesis cycle gas is fed into the return line 17 of the

Ammonia synthesis cycle 3 is fed into a position located downstream of the ammonia separator and upstream of the compressor 19. The resulting synthesis cycle gas, supplemented with fresh gas, is conveyed within the cycle in the synthesis cycle direction d and reaches the

Compressor 19, which is fluidically connected to the feed 2. In

Compressor, the synthesis cycle gas is compressed and conveyed to the converter 14, which is located downstream of the compressor 19 and is fluidly connected to the

Compressor 19 is connected. In converter 14 the reaction of the 230627P00LU

synthesis cycle gas to a synthesis cycle gas in which the

Ammonia concentration ideally corresponds to the equilibrium concentration of ammonia (depending on the activity of the specific catalyst used, the

ammonia concentration may also deviate from the equilibrium ammonia concentration). The output of the converter 14 is fluidically connected to the separation 15, in which the synthesis cycle gas stream is divided into two

The resulting second partial stream (which is larger in quantity) is fed back into the synthesis circuit via the return line 17, while the first partial stream is fed into the drain line 16 as purge gas and is removed from the

Ammonia synthesis cycle 3. The first partial stream can be used in the

Discharge line 16 is first fed to an ammonia separation (not shown), which may be based on fractional condensation (cryogenic) or membrane technology, and/or a hydrogen separation (not shown), which may be based on membrane technology; as a result, ammonia fractions contained in the first partial flow can be used as a product or can be used in the first

The hydrogen contained in the partial stream is returned to the synthesis cycle. The remaining vent gas is then

Flare and the resulting combustion gases of the first partial stream are released into the atmosphere. Separation 15 is fluidically connected to the

Ammonia separator 20, into which the second partial flow is fed via the

return line 17. In the ammonia separator 20, the

Synthesis cycle gas is cooled so that ammonia is produced in liquid form and is

Synthesis cycle gas can be separated and thus becomes available as a product. The remaining synthesis cycle gas is recycled from the ammonia separator 20 via the return line 17 to the feed 2.

Fig. 2 shows a schematic representation of a first embodiment of an ammonia synthesis plant according to the invention, on the basis of which in particular the

Implementation of a first embodiment of the process for producing ammonia zo is illustrated. The first embodiment differs from the conventional plant shown in Fig. 1 mainly in that in the plant shown in Fig. 2

Ammonia synthesis plant 1, the first partial stream separated from the synthesis cycle gas in the separation 15 is not discharged from the 230627P00LU

ammonia synthesis plant, but rather the fired

Burner device 5.1 as hydrogen-containing fuel gas. In addition, in the first embodiment shown in Fig. 2, the hydrocarbon-containing

Educt gas and the steam-containing educt gas are mixed together only in the pre-reformer 13 and not before entering the pre-reformer 13. Apart from these differences, the elements of the first embodiment shown in Fig. 2 are

Essentially identical to the conventional one shown in Fig. 1

Ammonia synthesis plant (identical = reference symbols describe corresponding components).

The plant shown in Fig. 2 also has a synthesis gas generation device 1 as a front end and an ammonia synthesis circuit 3 as a back end, which are connected via the

Feed 2 are connected to each other. The synthesis gas generation device 1 has three feeds for the reactant gases - the hydrocarbon feed 4, the steam feed 7 and the oxidant feed 8. These three

Educt gas feeds provide the educt gases, namely the hydrocarbon-containing

Educt gas, the air-based educt gas and the vapor-containing educt gas.

The hydrocarbon-containing reactant gas is provided via hydrocarbon feed 4.

This is fluidically connected to the pre-reformer 13, so that the hydrocarbon-containing reactant gas is introduced into the pre-reformer 13. Likewise, the steam supply 7, via which the steam-containing reactant gas is provided, is fluidically connected to the pre-reformer 13, so that the steam-containing

Educt gas is introduced into the pre-reformer 13. As steam-containing educt gas

Steam is used, which is provided here by a steam generator; however, this can also be generated in any other device.

Pre-reformer 13 is under relatively mild reform conditions at the

Pre-reforming converts at least a portion of the long-chain hydrocarbons of the hydrocarbon-containing feed gas into methane. The hydrocarbon-containing feed gas can also be subjected to prior processing before being introduced into the pre-reformer 13, for example, hydrogenation and/or desulfurization and/or preheating in a heat exchanger.

The pre-reformed gas mixture, which then mainly contains methane as

Containing hydrocarbons, is introduced into the gas heater 5. In this case, the pre-reformed gas mixture flows through the gas heater through a pipe whose 230627P00LU

The outside is heated via the fired burner device 5.1, resulting in a preheated, pre-reformed gas mixture. Instead of a tube, any other geometry is possible, for example, a hollow plate, as long as it is ensured that the gas mixture does not come into direct contact with the burner flame.

In addition, other reactant gas streams can also be preheated by the gas heater 5 by passing them through the gas heater 5 via pipes, hollow plates or the like.

Gas heaters, for example, the air-based reactant gas; the reactant gas streams to be heated can be passed individually or mixed with each other through the gas heater 5 and thereby heated (whereby, for reasons of explosion protection, it is typically refrained from passing the hydrocarbon-containing reactant gas or the pre-reformed gas mixture mixed with the air-based reactant gas through pipelines). In the fired

Burner device 5.1 in this case is a

Hydrogen burner, to which a hydrogen-containing fuel gas is supplied via the fuel gas line 5.2 (this is mixed with an oxidizing agent, in this case with

Air, whereby the oxidant and the fuel gas can also be fed to the burner separately and only then come into contact with each other in the combustion nozzle). In the present case, the fuel gas is the first partial flow of the synthesis cycle gas branched off in the separation 15, which is led out of the ammonia synthesis cycle 3 as purge gas via the purge line 16 and fed to the fuel gas line 5.2 (in the present case, the

Discharge line 16 into the fuel gas line 5.2, so that both lines are fluidically connected; however, both lines can also be identical, so that the discharge line 16 itself forms the fuel gas line 5.2.). The heat energy required to preheat the pre-reformed gas mixture is generated by combustion of the

Fuel gas is produced, which mainly contains hydrogen as fuel and only

Contains traces of methane.

The preheated pre-reformed gas mixture is used as well as the air-based

Educt gas from the oxidant feed 8 is fed directly into the autothermal reformer 6. The air-based educt gas used is air, which has been enriched with pure oxygen in a mixing device (not shown). The pure oxygen required for this purpose was extracted from air in an air separation unit 18, which is located upstream of the oxidant feed 8 and thus connected to it.

The gases supplied to the autothermal reformer 6 are first mixed with each other in nozzles in the autothermal reformer 6 and the resulting gas mixture is fed through a large number of nozzles into the interior of the autothermal

The gases are introduced into the autothermal reformer 6, in this case via several nozzles arranged radially and circularly on the reformer wall. Alternatively, the gases can also be introduced into the autothermal reformer 6 via separate nozzles without prior mixing.

The nozzle arrangement can also deviate from this arrangement, for example it is possible to introduce the individual gases or the gas mixture into the autothermal

Reformer 6, which is arranged centrally in a ceiling section of the autothermal reformer 6.

The resulting reformed gas mixture, which contains hydrogen, nitrogen,

Water, carbon monoxide, carbon dioxide and argon, also contains small amounts of oxygen and methane, is led out of the autothermal reformer 6 and the

Carbon oxide conversion 9. In this, the reformed gas mixture is subjected to a catalytic water gas shift reaction, whereby its content of

Carbon monoxide and water decreases and its content of carbon dioxide and

Hydrogen increases accordingly. The resulting carbon dioxide-enriched

Gas mixture is introduced into the carbon dioxide separation 10. The

Carbon dioxide separation 10 contains a gas scrubber in which the carbon dioxide-enriched gas mixture is mixed with a stream of alkaline

scrubbing liquid, which absorbs the carbon dioxide and removes it from the gas mixture, so that a gas mixture low in carbon dioxide is obtained.

At the same time, upon contact with the scrubbing liquid, part of the water vapor contained as a by-product in the carbon dioxide-enriched gas mixture is cooled, whereby this condenses out as process condensate and is also removed from the

The resulting carbon dioxide-laden

Washing liquid is led out of the gas scrubber and processed, whereby the

Carbon dioxide is extracted in gaseous form. The carbon dioxide is compressed and fed into a carbon dioxide storage facility 12, where it is compressed underground in deep sediment layers in a supercritical state as part of a CCS storage process, or stored in the form of carbonates or sorbed onto coal in coal seams. Alternatively, the carbon dioxide can be fed for further use via a pipeline system, for example, as an additive for carbonized 230627P00LU

Beverages in the food industry; in addition, any other form of

Storage of carbon dioxide is possible, which ensures that at least the

Most of the carbon dioxide stored in this way is not released (or at least only after a long

time) into the atmosphere.

The reformed gas mixture obtained from the gas scrubbing process, freed from carbon dioxide, still contains small amounts of carbon monoxide and carbon dioxide. Therefore, it is fed into a methanizer 11, where the carbon oxides are reduced to methane. A small portion of the

Hydrogen from the reformed gas mixture is used as a reducing agent. The resulting gas mixture contains hydrogen and nitrogen, only small amounts

Amounts of argon, methane and possibly traces of carbon dioxide, carbon monoxide and

Oxygen and is passed on to the feed 2, which in this case is a T-shaped pipe section, through which the oxygen from the

Synthesis gas generation device 1 originating (refined) reformed

Gas mixture is fed directly into the synthesis cycle gas, which is

Ammonia synthesis circuit 3 circulates. Instead of a T-shaped pipe section, all other suitable connections are possible, for example a Y-shaped pipe section or a mixing chamber, for example a cavity with internal baffles, in which the two gas streams meet and are swirled with the help of the baffles.

And thus mixed together.

The reformed gas mixture is fed into the ammonia synthesis circuit 3 into the return line 17 at a position which is located in

Synthesis cycle direction d downstream of the ammonia separator 20 and upstream of the compressor. The reformed gas mixture is added as fresh gas to the synthesis cycle gas of the ammonia synthesis cycle 3 and passes via the return line 17 to the suction side of the compressor 19, located downstream of the feed in the synthesis cycle direction d, in which it is compressed and via whose pressure side it is then discharged in the synthesis cycle direction d. From the compressor 19, the synthesis cycle gas is fed into the converter 14, which is located downstream of the compressor in the synthesis cycle direction d. Upstream of the compressor, the synthesis cycle gas can be preheated, for example via one or more heat exchangers, in which the thermal energy of the

Converter 14 outflowing synthesis cycle gas to preheat the 230627P00LU

Converter 14 incoming synthesis cycle gas can be used. In

Converter 14 is the site of the ammonia formation reaction, which occurs in equilibrium (or at least close to equilibrium), so that the conversion of nitrogen and

Hydrogen is not complete. In this case, converter 14 is a converter in which ammonia is produced according to the Haber-Bosch process. It is a three-stage converter (triple-bed converter) of approximately cylindrical shape (cylindrical shape), in which the introduced gas stream is successively passed through three

catalyst beds, whereby between two successive

A heat exchanger is arranged in each catalyst bed, so that after passing through the respective reactor stage, excess reaction heat of the exothermic

Formation reaction is removed from the synthesis cycle gas. Within the

Converter 14 has three catalyst beds arranged one above the other in an axial direction, with each of the three catalyst beds being designed as a cylindrical shell (i.e., in the form of a hollow cylinder) through which the synthesis cycle gas flows in a radial direction. Instead, other converter types can also be used as converter 14, for example, single-stage catalytic converters or multi-stage (e.g., two-stage, three-stage, or four-stage) converters, in which the individual

Converter stages are provided in the form of individual converters or in the form of

Converter beds, of which more than one is arranged in each converter housing, wherein the individual converter stages or converter beds are passed through by the synthesis cycle gas (in synthesis cycle direction d) sequentially and/or in parallel and the catalyst arrangements therein can have any suitable spatial structure and can be arranged, for example, in a radial or axial

direction can be traversed.

Downstream of the compressor 19 in the synthesis cycle direction d is the separation 15, in which the synthesis cycle gas is divided into two partial streams, the first partial stream and the second partial stream. The second partial stream represents the largest

Part of the synthesis cycle gas; this is transported in the synthesis cycle direction d by the

Return line 17 to feed 2, forming the circular zo synthesis cycle. In the return line 17, downstream of the separation 15 in the synthesis cycle direction d, the ammonia separator 20 is arranged, which is an ammonia refrigeration system that uses ammonia as

In this system, the ammonia is cooled to a temperature at which ammonia condenses out of the synthesis cycle and is thus used as

Target product in the form of liquid ammonia NHs is discharged from the ammonia synthesis cycle; other ammonia separators are possible, for example a

Refrigeration system operated with a refrigerant other than ammonia. s Downstream of the ammonia separator 20, the synthesis cycle gas with the reduced ammonia content is fed back to the feed 2 in the synthesis cycle direction d.

As already described, the first substream of the original

Synthesis cycle gas from the separation 15 via the discharge line 16 from the

Ammonia synthesis circuit 3 as purge gas and

Fuel gas line 5.2 of the fired burner device 5.1 as hydrogen-containing

It is possible to subject the first partial flow to ammonia separation (e.g. cryogenic or by means of

membrane technology) to remove the sludge contained in the first partial stream

Ammonia content can also be used as a product and at the same time to avoid that after the combustion of the fuel gas in the fired

Burner device 5.2 ammonia is released into the atmosphere. In principle, it would be possible to use the first partial stream in the ammonia plant according to the invention as in the ammonia synthesis plant according to the prior art, which was previously described in

connection with Fig. 1 — additionally subjected to hydrogen separation (e.g. by means of membrane technology) so that the hydrogen contained therein

Hydrogen content can be fed back into the synthesis cycle, however, for the vent gas which, according to the present invention, is derived from the

Ammonia synthesis cycle 3 is particularly advantageous if it has a higher hydrogen content, since this vent gas is to be used here as fuel gas, for which a certain proportion of hydrogen is required.

Fig. 3 shows a schematic representation of a second embodiment of an ammonia synthesis plant according to the invention, by means of which in particular the

Implementation of a second embodiment of the process for producing zo ammonia is illustrated. The second embodiment differs from the first embodiment shown in Fig. 2 in that in the embodiment shown in Fig. 3

Ammonia synthesis plant, the synthesis gas generation device 1 does not have a pre-reformer, that the hydrocarbon-containing reactant gas is mixed with the steam-containing reactant gas 230627P00LU only in the autothermal reformer 6 (and not already in a pre-reformer) and that in the ammonia synthesis plant shown in Fig. 3, the separation 15 between the ammonia separator 20 and the compressor 19 in

Synthesis circuit direction d is arranged upstream of the compressor 19. Apart from these differences, the elements of the second

Design essentially identical to the first shown in Fig. 2

Design (identical reference numerals describe corresponding

components), which particularly concerns the optional and alternative designs.

It is possible to dispense with a pre-reformer because the type of natural gas used as the hydrocarbon-containing feed gas already has a particularly high proportion of methane and a particularly low proportion of long-chain

hydrocarbons, so pre-reforming is not necessary. In this

In this case, the hydrocarbon-containing reactant gas is fed from the hydrocarbon feed 4 directly into the gas heater 5, through which it is passed in a tube heated by the fired burner device 5.1. Since pre-reforming is omitted, it is possible to add the steam-containing reactant gas to the hydrocarbon-containing reactant gas only in the autothermal reformer 6.

Separation 15 is arranged between the feed 2 and the compressor 19 and thus downstream of the ammonia separator 20. As a result of the

Arrangement downstream of the ammonia separator 20 and upstream of the

Converter 14, the synthesis cycle gas circulating through the return line 17 has a very low ammonia content, so that in the separation 15 with the first

Partial flow only a small amount of ammonia is discharged from the ammonia synthesis circuit 3 as vent gas and is lost as a product; a separate ammonia separation in the

Drain line 16 is therefore not required. Due to the arrangement upstream of the

Compressor 19, the first partial flow is already branched off from the synthesis cycle gas when the synthesis cycle gas enters the compressor 19 and is therefore not

Compressor 19 compresses. Consequently, it is possible to make compressor 19 slightly smaller.

Fig. 4 shows a schematic representation of a third embodiment of an ammonia synthesis plant according to the invention, by means of which in particular the

Implementation of a third embodiment of the process for producing ammonia 230627P00LU. The third embodiment differs from the second embodiment shown in Fig. 2 in that in the embodiment shown in Fig. 4

Ammonia synthesis plant the hydrocarbon-containing reactant gas and the steam-containing

Educt gas are mixed together before entering the pre-reformer 13 (and not only in the pre-reformer 13), so that the synthesis gas generation device 1 does not

Carbon oxide converter and no methanizer, that the branch line 21 is provided to branch off a partial flow of the reformed gas mixture upstream of the feed 2 before being introduced into the ammonia synthesis cycle and to the fuel gas line 5.2 as additional fuel gas of the fired

burner device 5.1 and that the separation 15 between the

Compressor 19 and the converter 14 is arranged here in the synthesis cycle direction d upstream of the converter 14. Apart from these differences, the

Elements of the third embodiment shown in Fig. 4 are essentially identical to the first embodiment shown in Fig. 2 (identical reference numerals describe

Corresponding components in each case), which particularly also applies to the optional and alternative designs.

The hydrocarbon-containing reactant gas and the steam-containing reactant gas are therefore combined upstream of the pre-reformer 13 and thus also upstream of the gas heater 5 and fed as a combined gas mixture through a common pipeline to the pre-reformer 13. In this way, the pre-reformer 13 takes over part of the process load of the autothermal reformer 6. By using a particularly efficient

Carbon dioxide separation 10, for example using multi-stage pressure swing adsorption, makes it possible to quantitatively separate the small amounts of carbon monoxide as well as the total carbon dioxide, so that methanation is also not necessary.

From the connecting line, which fluidically connects the carbon dioxide separation 10 with the feed 2, another line branches off, branch line 21. Via branch line 21, a part of the processed reformed gas mixture is still in the synthesis gas generation device 1 and thus before being introduced into the

Ammonia synthesis circuit branched off as a partial stream. Branch line 21 is connected to the zo discharge line 16, so that the two partial streams, which are connected via the respective

Lines are led away, combined with each other and together into the

Fuel gas line 5.2. This means that both partial flows of the fired

Burner device 5.1 as hydrogen-containing fuel gases, the partial stream 230627P00LU with the processed reformed gas mixture as well as the first partial stream with the branched synthesis cycle gas. In this way, it is possible to dispense with an additional fuel gas supply in the fired burner device 5.1, for example via a supply of natural gas. Finally, the separation 15 is provided between the compressor 19 and the converter 14. Just as in the second embodiment shown in Fig. 3, the discharge gas from the

Ammonia synthesis circuit 3 discharged first partial flow a small

ammonia content, so that in the drain line 16 a separate

Ammonia separation for ammonia recovery can be dispensed with.

At the same time, however, the branched first partial flow is already compressed and thus has a higher pressure than the partial flow discharged via the branch line 21. In this way, the connection between the discharge line 16 and the branch line 21, which are continued together in the fuel gas line 5.2, can be designed as a jet pump, in which the first partial flow conducted via the discharge line 16 from the

Synthesis cycle gas as the driving medium for the branch line 21

partial stream from the reformed gas mixture, which enables precise mixing of the latter partial stream to the former partial stream.

Fig. 5 shows a schematic representation of a fourth embodiment of an ammonia synthesis plant according to the invention, by means of which in particular the

Implementation of a fourth embodiment of the process for producing ammonia is illustrated. The fourth embodiment differs from the second embodiment shown in Fig. 2 in that in the embodiment shown in Fig. 5

Ammonia synthesis plant, the synthesis gas generation device 1 has no pre-reformer and no air separation, that the steam-containing reactant gas is fed into the gas heater 5 (and not into the pre-reformer), that within the

Ammonia synthesis circuit 3, the order of converter 14 and separation 15 was reversed (so that converter 14 is now located downstream of separation 15 and upstream of ammonia separator 20) and feed 2 was located between converter 14 and ammonia separator 20. Apart from these differences, the elements of the fourth

Design essentially identical to the first shown in Fig. 2

Design (identical reference numerals describe corresponding 230627P00LU

components), which particularly concerns the optional and alternative designs.

As in the second embodiment shown in Fig. 3, here a

Pre-reformer is dispensed with and the hydrocarbon-containing reactant gas is

Hydrocarbon feed 4 is fed directly to the gas heater 5, which it is heated in a

pipe, which is heated by the fired burner device 5.1. The

Furthermore, the steam-containing reactant gas is supplied to the gas heater from the steam supply 7, which the steam-containing reactant gas also passes through in a pipe which is different from the pipe in which the hydrocarbon-containing reactant gas is passed through the gas heater 5 and which is also connected to the fired

burner device 5.1. At the outlet of the gas heater 5, the two

Pipes are brought together and the hydrocarbon-containing reactant gas is mixed with the steam-containing reactant gas, so that they are fed to the autothermal reformer 6 via a common pipeline. The oxidant feed 8 is connected to the autothermal reformer 6, so that the air-based reactant gas is fed separately to the autothermal reformer 6. The air-based reactant gas here is a

Gas mixture obtained from air, from which nitrogen has been removed and which is supplied via a gas pipeline, which is why direct connection to an air separation unit is not necessary. Due to the different arrangement of the

Components of the ammonia synthesis cycle 3, the synthesis cycle gas passes through the components of the ammonia synthesis cycle 3 in a different order, namely such that the synthesis cycle gas in the synthesis cycle direction d after

Reaching the feed 2, it first enters the ammonia separator 20 and then the compressor 19, before it enters the separation 15 and subsequently the

Converter 14 and finally reaches the feed 2 again. This removes water contained in the reformed gas mixture (also a gas mixture without a separate

Water separation in the synthesis gas generation device 1) after feeding into the ammonia synthesis circuit 3 in the ammonia separator 20 from the

Synthesis cycle gas is removed before the synthesis cycle gas is fed to the converter 14 zo.

Fig. 6 shows a schematic representation of a fifth embodiment of an ammonia synthesis plant according to the invention, by means of which in particular the

Implementation of a fifth embodiment of the process for producing ammonia 230627P00LU. The fifth embodiment differs from the third embodiment shown in Fig. 4 in that in the embodiment shown in Fig. 6

Ammonia synthesis plant, the separation 15 is not arranged between the compressor 19 and the converter 14, but is arranged between the ammonia separator 20 and the compressor 19 in the synthesis cycle direction d upstream of the compressor 19. Apart from these differences, the elements of the fifth embodiment shown in Fig. 6 are essentially identical to the third embodiment shown in Fig. 4 (identical reference numerals describe corresponding components), which in particular also includes the optional and alternative

Regarding designs.

As in the third embodiment shown in Fig. 4, the three

Educt gases are mixed together before being introduced into the pre-reformer 13 and fed to it via a common pipeline. As in the third embodiment shown in Fig. 4, neither a carbon oxide converter nor a methanizer are provided here, and branch line 21 branches off from the connecting line between carbon dioxide separation 10 and feed 2. The separation 15, in which the first partial stream is branched off from the synthesis cycle gas in order to feed it to the fired burner device 5.1, is here, however, between the

Ammonia separator 20 and feed 2, i.e. downstream of the

Ammonia feed 20 and upstream of feed 2. This arrangement offers the advantage that the branched first partial flow of the synthesis cycle gas also contains only little ammonia, but in addition the fresh gas has not yet been fed into the synthesis cycle gas, so that the loss of hydrogen and

Nitrogen for the ammonia synthesis circuit 3 is lower. The drain line 16 and the branch line 21 are - if necessary with the help of a pressure reducer -

To equalize the different pressures of both partial gas streams, they are combined and flow into the fuel gas line 5.2, via which they are fed to the fired burner device 5.1. 230627P00LU

List of reference symbols 1 Synthesis gas generation device 2 Feed 3 Ammonia synthesis circuit 4 Hydrocarbon feed 5 Gas heater 5.1 Fired burner device 5.2 Fuel gas line 6 Autothermal reformer 0 7 Steam feed 8 Oxidant feed 9 Carbon oxide converter

Carbon dioxide separation 11 Methanizer 12 Carbon dioxide storage 13 Pre-reformer 14 Converter 15 Separation 16 Discharge line 17 Return line 18 Air separation 19 Compressor 20 Ammonia separator 21 Branch line dd Synthesis cycle direction 230627P00LU

Claims (16)

' LU103206 Claims 1. A process for producing ammonia, comprising the steps of a) providing three reactant gases, namely a hydrocarbon-containing reactant gas, an air-based reactant gas, and a steam-containing reactant gas, b) heating at least one of the three reactant gases with a fired burner device (5.1), whereby at least one heated reactant gas is obtained, c) feeding the at least one heated reactant gas and the remaining three reactant gases into an autothermal reformer (6), d) autothermally reforming the three reactant gases, whereby a reformed gas mixture is obtained, e) feeding the reformed gas mixture into an ammonia synthesis cycle with a synthesis cycle gas, f) converting the synthesis cycle gas in a converter (14), whereby ammonia is generated in the synthesis cycle gas, and g) dividing the synthesis cycle gas into a first partial stream and a second partial stream, characterized in that the first partial stream of the fired burner device (5.1) is supplied as hydrogen-containing fuel gas. 2. The process of claim 1, further comprising the steps of h) recycling the second partial stream to feed the reformed gas mixture, and i) removing ammonia from the synthesis cycle gas. 3. The method according to claim 1 or 2, wherein the air-based reactant gas is air which has been enriched with oxygen, in particular with oxygen from an air separation (18). 4. A process according to any one of claims 1 to 3, wherein the reformed gas mixture is subjected to a carbon oxide 230627P00LU Conversion, in which carbon monoxide reacts to form carbon dioxide, followed by carbon dioxide separation, in which carbon dioxide is removed from the reformed gas mixture, followed by methanation, in which carbon oxides in the reformed gas mixture are converted to methane. 5. The method according to claim 4, wherein the carbon dioxide removed from the reformed gas mixture is fed to a carbon dioxide storage (12). 6. The method according to any one of claims 1 to 5, wherein the reformed gas mixture is divided into two partial streams before being fed into the synthesis cycle gas, one partial stream of which is fed into the synthesis cycle gas and the other partial stream of which is fed to the fired burner device (5.1) in addition to the first partial stream of the synthesis cycle gas as hydrogen-containing fuel gas, wherein in particular the hydrogen-containing fuel gas of the fired burner device (5.1) consists of the first partial stream of the synthesis cycle gas and of the partial stream of the reformed gas mixture. 7. The method according to any one of claims 1 to 6, wherein the hydrocarbon-containing reactant gas is pre-reformed before being fed into the autothermal reformer (6). 8. Ammonia synthesis plant, in particular for carrying out a process according to one of claims 1 to 7, with a synthesis gas generation device (1) for generating a reformed gas mixture using three reactant gases, namely a hydrocarbon-containing reactant gas, an air-based reactant gas and a steam-containing reactant gas, an ammonia synthesis circuit (3) for generating ammonia in a synthesis circuit gas conveyed in a synthesis circuit direction (d), and a feed (2) for feeding the reformed gas mixture into the synthesis circuit gas, wherein the synthesis gas generation device (1) and the ammonia synthesis circuit (3) are fluidically connected via the feed (2), wherein the synthesis gas generation device (1) has an autothermal reformer (6) 230627P00LU for generating the reformed gas mixture using the three reactant gases and a gas heater (5) for heating at least one of the three Educt gases before being fed into the autothermal reformer (6), wherein the gas heater (5) has a fired burner device (5.1) which can be operated with a fuel gas, wherein the ammonia synthesis cycle (3) has a converter (14) for generating ammonia in the synthesis cycle gas and a separator (15) for separating the synthesis cycle gas into a first partial stream and a second partial stream, wherein the separator (15) is connected to a discharge line (16) for discharging the first partial stream, characterized in that the discharge line (16) of the separator (15) is fluidically connected to the fired burner device (5.1) for supplying the first partial stream as fuel gas to the fired burner device (5.1). 9. Ammonia synthesis plant according to claim 8, wherein the synthesis gas generation device (1) has at least three reactant gas feeds, namely a hydrocarbon feed (4) for providing the hydrocarbon-containing reactant gas, an oxidant feed (8) for providing the air-based reactant gas and a steam feed (7) for providing the steam-containing reactant gas, wherein the gas heater (5) is fluidically arranged between at least one reactant gas feed and the autothermal reformer (6), wherein the fired burner device (5.1) has a fuel gas line (5.2) for supplying the first partial stream as hydrogen-containing fuel gas, which is fluidically connected to the discharge line (16), wherein the ammonia synthesis circuit (3) has a compressor (19) for conveying the synthesis cycle gas in the synthesis cycle direction (d) and an ammonia separator (20) for removing ammonia from the synthesis cycle gas wherein the separation (15) is connected, in addition to the discharge line (16), to a return line (17) for returning the second partial flow to the feed (2). 230627P00LU 10. Ammonia synthesis plant according to one of claims 8 or 9, wherein the separation (15) is arranged downstream of the converter (14) and upstream of the feed (2) in the synthesis cycle direction (d). 11. Ammonia synthesis plant according to one of claims 8 to 10, wherein the synthesis gas generation device (1) has an air separation (18) for providing oxygen-enriched air as air-based reactant gas. 12. Ammonia synthesis plant according to one of claims 8 to 11, wherein the synthesis gas generation device (1) has, between the autothermal reformer (6) and the feed (2), a carbon oxide converter (9) for converting the carbon monoxide to carbon dioxide, a carbon dioxide separation (10) for removing carbon dioxide from the reformed gas mixture and a methanizer (11) for converting carbon oxides in the reformed gas mixture into methane, wherein the carbon oxide converter (9) is fluidically connected to the autothermal reformer (6) and the carbon dioxide separation (10), the carbon dioxide separation (10) is fluidically connected to the carbon oxide converter (9) and the methanizer (11), and the methanizer (11) is fluidically connected to the carbon dioxide separation (10) and the feed (2). 13. Ammonia synthesis plant according to claim 12, wherein the carbon dioxide separation (10) is fluidly connected to the carbon dioxide storage (12) for storing the carbon dioxide removed from the reformed gas mixture. 14. Ammonia synthesis plant according to one of claims 8 to 13, wherein the synthesis gas generation device (1) has, in the conveying direction of the reformed gas mixture, downstream of the autothermal reformer (6) and upstream of the feed (2), a divider for dividing the reformed gas mixture into two partial streams, wherein the divider has a line for feeding one partial stream of the reformed gas mixture into the synthesis cycle gas, which is fluidically connected to the inlet, and a branch line (21) for supplying the other partial stream of the reformed gas mixture in addition to the first partial stream from the synthesis cycle gas as fuel gas to the 230627P00LU fired burner device (5.1), wherein the branch line (21) is fluidically connected to the fired burner device (5.1). 15. Ammonia synthesis plant according to one of claims 8 to 14, wherein the synthesis gas generating device (1) has, upstream of the autothermal reformer (6) in the conveying direction of the hydrocarbon-containing reactant gas, a pre-reformer (13) for pre-reforming the hydrocarbon-containing reactant gas, which is fluidically connected to the autothermal reformer (6). 16. Method for converting an ammonia synthesis plant with a synthesis gas generation device (1) for generating a reformed gas mixture using three reactant gases, namely a hydrocarbon-containing reactant gas, an air-based reactant gas and a steam-containing reactant gas, an ammonia synthesis circuit (3) for generating ammonia in a synthesis circuit gas conveyed in a synthesis circuit direction (d), and with a feed (2) for feeding the reformed gas mixture into the synthesis circuit gas, wherein the synthesis gas generation device (1) and the ammonia synthesis circuit (3) are fluidically connected via the feed (2), wherein the synthesis gas generation device (1) has an autothermal reformer (6) for generating the reformed gas mixture using the three reactant gases and a gas heater (5) with a fired burner device (5.1) for heating at least one of the three reactant gases before feeding into the autothermal reformer (6), wherein the ammonia synthesis cycle (3) has a converter (14) for generating ammonia in the synthesis cycle gas, characterized in that a discharge line (16) is installed which connects the ammonia synthesis cycle with the fired burner device (5.1) for supplying a discharged partial flow as hydrogen-containing fuel gas to the fired burner device (5.1) connects. 230627P00LU