EP4298187A1 - System and process for producing synthetic fuels without emitting carbon dioxide - Google Patents

Abstract

The invention relates to a system for producing synthetic fuels, in particular aviation turbine fuel (kerosene), petroleum and/or diesel, the system comprising: a) a synthesis gas production device for producing a raw synthesis gas from methane, water and carbon dioxide, wherein the synthesis gas production device comprises at least one reaction portion in which methane, water and carbon dioxide react to form the raw synthesis gas, and at least one heat generation portion in which, by combusting fuel to form flue gas, the heat required for reacting methane and carbon dioxide to form the raw synthesis gas is generated; b) a separating device for separating carbon dioxide from the raw synthesis gas produced in the synthesis gas production device; c) a Fischer-Tropsch device for producing, by means of a Fischer-Tropsch process, hydrocarbons from the synthesis gas from which carbon dioxide was separated in the separating device; and d) a refining device for refining the hydrocarbons produced in the Fischer-Tropsch device to form the synthetic fuels; wherein the system further comprises: e1) a separating device for separating carbon dioxide from the flue gas removed from the synthesis gas production device via the removal line for flue gas; and/or e2) a flue gas recirculation line, which is connected to the heat generation portion of the synthesis gas production device; wherein i) the carbon dioxide separated from the flue gas, or, via the flue gas recirculation line, the flue gas and ii) the carbon dioxide separated from the raw synthesis gas are either directly fed to the synthesis gas production device or first fed to a carbon dioxide compressing device and fed from there to the synthesis gas production device; wherein the system also comprises an electrolysis device for separating water into hydrogen and oxygen; wherein the electrolysis device comprises a water supply line, an oxygen removal line and a hydrogen removal line; and wherein a line leads from the oxygen removal line into the supply line for oxygen-containing gas to the synthesis gas production device.

Description

Plant and process for the production of synthetic fuels without carbon dioxide emissions

The present invention relates to a plant and a method for producing synthetic fuels, in particular jet fuel, diesel and/or naphtha.

There are a number of different processes for producing fuels, such as jet fuel, diesel, naphtha or the like. Such methods are mainly based on the processing of fossil raw materials, such as the refining of crude oil, the liquefaction of coal or the synthesis of fuels from natural gas, water and oxygen. The synthesis of fuels from natural gas, water and oxygen is also known as the “gas-to-liquids” process. In this process, a synthesis gas comprising hydrogen and carbon monoxide is first produced from natural gas, water and oxygen, which is then converted into hydrocarbons in a Fischer-Tropsch synthesis, which consist primarily of long-chain normal paraffins. These hydrocarbons are then converted into synthetic fuels by cracking and isomerization.

A similar process is the conversion of electrical energy into synthetic fuels, known as “power-to-liquids”. For this purpose, water and carbon dioxide are converted into synthesis gas, which is then processed into synthetic fuels in a similar way to the "gas-to-liquids" process. An alternative process known as “power and biomass-to-liquids” uses biomass such as biomethane and biogas or synthetic methane as a carbon source in addition to carbon dioxide from the air or from point sources, thereby completely replacing fossil carbon sources such as petroleum or Natural gas. For example, in such a process, methane, water (vapor) and carbon dioxide are converted into synthesis gas, which is then further processed into synthetic fuels in a manner similar to the processes mentioned above.

A major disadvantage of the above methods is that significant amounts of carbon dioxide are generated and emitted. However, this is undesirable for environmental reasons and in particular for climate protection reasons. In addition, these processes require larger amounts of fresh water and generate large amounts of waste water. However, water of the required purity is an expensive raw material and large amounts of waste water are problematic for environmental reasons.

Based on this, the present invention was based on the object of providing a plant and a method for the production of synthetic fuels, which (s) can be operated with low energy requirements without carbon dioxide emissions or, if at all, with minimal carbon dioxide emissions, which only requires a small amount of fresh water supply required and can be operated with small amounts of waste water, and which can still be operated at least almost exclusively with electrical energy and biomass.

According to the invention, this object is achieved by a plant according to patent claim 1 and in particular by a plant for the production of synthetic fuels, in particular jet turbine fuel, diesel and/or naphtha, which comprises: a) a (first) synthesis gas production facility for producing a raw synthesis gas comprising carbon monoxide, hydrogen and carbon dioxide from methane, water and carbon dioxide, the synthesis gas production facility having at least one reaction section in which methane, water and carbon dioxide react to form the raw synthesis gas, and at least one heat generation section, in in which the heat required for the reaction of methane and carbon dioxide to form the raw synthesis gas is generated by burning fuel to form flue gas, the reaction section comprising a supply line for methane, a supply line for water, at least one supply line for carbon dioxide and a discharge line for raw synthesis gas, and the heat generation section comprises one Supply line for fuel, a supply line for oxygen-containing gas and a discharge line for flue gas, b) a separating device for separating carbon dioxide from the in the synthesis gas production unit ute with a discharge line for carbon dioxide and a discharge line for synthesis gas, c) a Fischer-Tropsch device for the production of hydrocarbons by a Fischer-Tropsch process from the synthesis gas, from which carbon dioxide was separated in the separation device, and d) a Refining device for refining the hydrocarbons produced in the Fischer-Tropsch device into the synthetic fuels, the plant further comprising: ei) a separating device for separating carbon dioxide from the flue gas discharged from the synthesis gas production device via the discharge line for flue gas, the separating device having a discharge line for carbon dioxide, the discharge line for carbon dioxide of the separating device for separating carbon dioxide from the discharge line for flue gas from the synthesis gas production device conducted flue gas and the discharge line for carbon dioxide of the separating device for separating carbon dioxide from the raw synthesis gas produced in the synthesis gas production device are either connected directly to one of the at least one supply line for carbon dioxide of the synthesis gas production device or the discharge line for carbon dioxide of the separating device for separating carbon dioxide from the via the discharge line flue gas discharged for flue gas from the synthesis gas production facility and the discharge line for carbon dioxide of the separating device for separating carbon dioxide from the raw synthesis gas produced in the synthesis gas production facility are connected to a carbon dioxide compression device which has a discharge line which is connected to one of the at least one supply line for carbon dioxide of the synthesis gas production facility, and or

Q2) a flue gas recirculation line connected to the flue gas discharge line of the synthesis gas production facility, the flue gas recirculation line and the carbon dioxide discharge line of the separation facility for separating carbon dioxide from the raw synthesis gas produced in the synthesis gas production facility being connected either directly to one of the at least one carbon dioxide supply line of the synthesis gas production facility or to the Flue gas recirculation line and the discharge line for carbon dioxide of the separating device for separating carbon dioxide from the raw synthesis gas produced in the synthesis gas production device are connected to a carbon dioxide compression device that has a discharge line that is connected to one of the at least one supply line for carbon dioxide of the synthesis gas production device, the plant also having an electrolysis device for separating water into hydrogen and oxygen, wob ei the electrolysis device a water supply line, an oxygen discharge line and a hydrogen discharge line and wherein a line leads from the oxygen discharge line into the oxygen-containing gas supply line to the synthesis gas production facility.

By not only separating the carbon dioxide remaining in the reaction product of the synthesis gas production facility, i.e. in the raw synthesis gas, in the plant according to the invention and in the method according to the invention and returning it to the synthesis gas production facility, but also that in the synthesis gas production facility - to provide the necessary for the strongly endothermic reaction Heat generated by combustion - flue gas is either completely returned to the synthesis gas production facility and / or the carbon dioxide contained therein is separated from the flue gas and then the separated carbon dioxide is returned to the synthesis gas production facility, the entire carbon dioxide is utilized in the process and carbon dioxide emissions are reliably avoided. In addition, according to the invention, at least part of the oxygen-containing gas required for burning the fuel in the heat generation section of the synthesis gas production device is covered by oxygen produced in the electrolysis device. In this way, the proportion of air used as combustion gas can be significantly reduced or even reduced to zero, namely by the oxygen produced by the water electrolysis, which is operated exclusively with electrical energy. Due to the reduced amount of air in the mixture of fuel, oxygen and air, the gas volume to be heated to the combustion temperature in the heat generation section of the synthesis gas production facility is significantly reduced because the nitrogen content (about 79% of the air) is substituted by the oxygen originating from the electrolysis proportion of air is omitted. This leads to a reduction in the fuel requirement, because significantly lower heat outputs have to be provided for the same reaction enthalpy, and thus to a reduction in the energy requirement of the plant. In addition, this leads to a reduction in the volume of carbon dioxide-containing flue gas that is produced during combustion. This not only reduces the amount of carbon dioxide that is released via the Flue gas must be circulated, reduced, which is why the cooling capacity for the flue gas can be significantly reduced, but in particular also increases the hydrogen-to-carbon monoxide ratio in the raw synthesis gas. As a result, the amount of hydrogen to be fed to the synthesis gas production device to set the desired hydrogen-to-carbon monoxide ratio in the raw synthesis gas, which hydrogen is preferably also produced in the electrolysis device, is reduced. Thus, according to the invention, a significant part of the oxygen-containing gas required to burn the fuel in the heat generation section of the synthesis gas production facility and preferably also the hydrogen required to set the desired hydrogen-to-carbon monoxide ratio in the raw synthesis gas is produced solely by electrical energy by means of water electrolysis. In principle, it is possible to cover all of the oxygen-containing gas required for burning the fuel in the heat generation section of the synthesis gas production facility solely with oxygen from the electrolysis facility, although in large-scale plants for safety reasons the synthesis gas production facility also uses a certain proportion of air or another suitable substance Gas, such as carbon dioxide, can be supplied so that the oxygen content of the combustion mixture and thus the combustion temperature is not too high. A further particular advantage of the system according to the invention and the method according to the invention is that the water required for the electrolysis can be produced from the waste water produced when carrying out the method according to the invention in the system according to the invention, as is explained further below in relation to particularly preferred embodiments of the The present invention is described, and as a result the use of fresh water can be dispensed with completely or at least as far as possible. Apart from that, the system according to the invention and the method according to the invention make it possible to significantly reduce the amount of unused exhaust gases and waste water, since the the process gases and the waste water in the individual parts of the plant, such as in the electrolysis device, can and are reused. In particular, biomethane or synthetic methane produced from green input materials is used as methane, and green electricity in particular is used as electrical energy. As an alternative to biomethane, methane from any other source can also be used and in particular any methane-containing gas mixture, such as biogas, can be used, which preferably contains 30 to 70% by volume of methane and 70 to 30% by volume of carbon dioxide and particularly preferably 40 to 60% by volume methane and 60 to 40% by volume carbon dioxide, such as about 50% by volume methane and about 50% by volume carbon dioxide. Consequently, the method according to the invention conserves resources, since natural and fossil raw materials such as crude oil, natural gas and the like are not required. Overall, the present invention enables the complete conversion of methane, carbon dioxide occurring in the process and water by means of electrical energy to synthetic fuels via fully integrated process units while avoiding any carbon dioxide emissions, without significant continuous amounts of exhaust gas and at most a minimized waste water flow to synthetic fuels such as jet fuel. Diesel and/or petroleum, for example kerosene (SAF - 'Sustainable Aviation Fuet'), petroleum and/or light petroleum. Finally, the method according to the invention is characterized by a comparatively low energy requirement. All of this is achieved through the synergistic interaction of the electrolysis device and the flue gas treatment in accordance with system features ei) and e2).

According to the invention, the separating device b) is designed to separate carbon dioxide from the raw synthesis gas produced in the synthesis gas production device, the Fischer-Tropsch device c) is designed to produce hydrocarbons by a Fischer-Tropsch process from the synthesis gas from which in the separating device b) Carbon dioxide was separated, designed, and the refining facility d) is designed to refine the hydrocarbons produced in the Fischer-Tropsch facility c) into synthetic fuels. This means that the separation device b) for separating carbon dioxide is connected to the synthesis gas production device a) via the discharge line for raw synthesis gas of the synthesis gas production device a), which is a Fischer-Tropsch device c) for the production of hydrocarbons by a Fischer-Tropsch process to the separation device b) via a synthesis gas feed line and the refining device d) is connected to the Fischer-Tropsch device d) via a hydrocarbon feed line.

As explained above, the core of the present invention is the synergistic interaction of the flue gas treatment according to the system features ei) or e2) and the electrolysis device. For this it is essential to separate all the carbon dioxide that occurs during the operation of the plant according to the invention or during the implementation of the method according to the invention and to return it to the synthesis gas production facility, i.e. not only to separate the carbon dioxide remaining in the reaction product of the synthesis gas production facility, i.e. in the raw synthesis gas, but in particular and above all also the flue gas produced in the synthesis gas production facility - to provide the heat required for the strongly endothermic reaction by burning - either completely returned to the synthesis gas production facility and/or to separate the carbon dioxide contained therein from the flue gas and then to transfer the separated carbon dioxide to the Attributed to synthesis gas production facility. It is therefore very particularly preferred according to the present invention that the system does not have a carbon dioxide discharge line or that no carbon dioxide is discharged during operation of the system. The method according to the invention therefore very particularly preferably has a completely neutral carbon dioxide balance. An essential part of the plant according to the invention is the synthesis gas production device b) for the production of a carbon monoxide, hydrogen and carbon dioxide-comprising raw synthesis gas from methane, water and carbon dioxide. In this context, production of a raw synthesis gas comprising carbon monoxide, hydrogen and carbon dioxide from methane, water and carbon dioxide means that the starting gas mixture contains methane, water and carbon dioxide, but can also contain other components. In particular, biogas can be used as a methane source, which contains 30 to 70% by volume of methane and 70 to 30% by volume of carbon dioxide and preferably 40 to 60% by volume of methane and 60 to 40% by volume of carbon dioxide, such as 50% by volume % methane and about 50% by volume carbon dioxide. The supply line for methane accordingly designates a supply line for a methane-containing gas, which can be biogas or pure methane, for example. The synthesis gas production facility b) is preferably a dry reformer. The dry reformer preferably contains a nickel oxide catalyst and can be operated at a pressure of from 10 to 50 bar and a temperature of from 700 to 1,200.degree. In addition to methane and steam, a dry reformer can also process carbon dioxide, with these reactions being very strongly endothermic. The dry reformer therefore requires appropriate heating in order to provide the energy or heat required for the endothermic reaction, which according to the invention is preferably achieved by burning fuel with an oxygen-containing gas, which is oxygen from the electrolysis and possibly air or another suitable gas is composed is achieved. According to a particularly preferred embodiment of the present invention, the fuel required for this purpose is provided completely or at least almost completely by exhaust gases or combustible gases and synthetic fuel generated during operation of the system, ie to manage without or at least almost without external fuel. The methane fed to the dry reformer can be freed from sulfur impurities beforehand, for example in a hydrogenation plant using hydrogen. For this purpose, it is proposed in a development of the inventive idea that the Fischer-Tropsch device or the refining device and particularly preferably the Fischer-Tropsch device and the refining device each have a gas discharge line which is/are connected to the supply line for fuel of the synthesis gas production device in order to so to use the waste gases produced in the Fischer-Tropsch reaction and in refining, which have a calorific value, as fuel or combustible gas for heating the synthesis gas production facility.

In addition, it is preferred that the refining facility has one or more synthetic fuel product discharge lines, wherein at least one of the one or more synthetic fuel product discharge lines is connected via a return line to the fuel supply line of the synthesis gas production facility, so that part of the fuel produced in the refining facility synthetic fuel, such as light gasoline in particular, can be conducted as fuel in the heat generation section of the synthesis gas production facility. Thus, if the exhaust gases generated in the Fischer-Tropsch facility and in the refining facility do not have a sufficient total calorific value to generate the heat required for the operation of the synthesis gas production facility when they are burned, the required residual amount of energy or heat can flow through Supplying a corresponding amount of synthetic fuel produced in the plant, such as light petrol in particular, are generated in order to be able to dispense with the supply of external fuel.

For example, the refining facility may have a kerosene (SAF) product discharge line, a naphtha product discharge line, and a light naphtha product discharge line, with the return line being derived from one or more of these product discharge lines and preferably the product discharge line for mineral spirits into the fuel supply line of the syngas production facility.

According to a further preferred embodiment of the present invention, it is provided that the plant comprises a control device which controls the amount of synthetic fuel fed into the heat generation section of the synthesis gas production device as fuel in such a way that no external fuel has to be supplied to the synthesis gas production device and preferably to the entire plant .

In a further development of the inventive idea, it is proposed that the synthesis gas production device, which is preferably designed as a dry reformer, comprises one or more tube bundle reactors, with the tubes of each tube bundle reactor forming the reaction section and the area outside the tubes forming the heat generation section. As a result, the educts methane, steam and carbon dioxide can be heated quickly, evenly and effectively to the temperature required for generating the raw synthesis gas in a structurally simple manner. One or more suitable nickel oxide catalysts are arranged in the tubes, such as SYNSPIRE™ G1-110 (BASF catalyst). During operation of the plant, the educts in the tubes of the dry reformer are heated by the combustion of the fuel in the heat generation section of the dry reformer, preferably at 10 to 50 bar, particularly preferably 20 to 40 bar, such as about 30 bar, to 700 to 1,200° C. particularly preferably 800 to 1100°C, more preferably 900 to 950°C, such as about 930°C. The conversion of the carbon dioxide in the dry reformer with methane and steam reaches only a maximum of 50% in practice, even under optimal conditions, so that the carbon dioxide concentration in the raw synthesis gas produced is about 30% by volume. This comparatively high concentration of carbon dioxide would heavily burden the Fischer-Tropsch synthesis, in which carbon dioxide is an inert gas, and the carbon dioxide would be recycled as part of the flue gas after the Fischer-Tropsch synthesis with the flue gas of the Fischer-Tropsch facility to the dry reformer, where it would reduce the combustion efficiency and enter the flue gas. In order to avoid all the associated disadvantages, the carbon dioxide is separated from the raw synthesis gas in the plant according to the invention in the separating device b).

Hydrogen is required for the iso-hydrocracker reactor preferably contained in the refining device and for the hydrogen stripper preferably also contained therein. For this purpose, it is proposed in a further development of the idea of the invention that hydrogen generated in the electrolysis device be used for this purpose. Therefore, a line preferably leads from the hydrogen discharge line of the electrolysis device to the Fischer-Tropsch device and/or a line to the refining device. A line preferably leads from the hydrogen discharge line of the electrolysis device to the Fischer-Tropsch device and a line to the refining device and preferably also a line to the synthesis gas compression device.

The electrolytic device preferably comprises one or more solid oxide electrolytic cells, one or more polymer electrolyte membrane electrolytic cells and/or one or more alkaline electrolytic cells. For example, hydrogen is produced by alkaline low-temperature, high-pressure water electrolysis.

According to the invention, the synthesis gas production device comprises a hydrogen supply line which is preferably connected to the hydrogen discharge line of the electrolysis device. As a result, hydrogen can be supplied to the synthesis gas production device during operation of the plant according to the invention and the H2/CO molar ratio of the raw synthesis gas produced in the synthesis gas production device can thereby be adjusted. This is why In this embodiment it is also preferred that the plant comprises a control device which controls the amount of hydrogen fed into the synthesis gas production facility in such a way that the H2/CO molar ratio in the raw synthesis gas produced in the synthesis gas production facility is 1.13 to 1.80 and preferably 1 1.15 to 1.50, such as 1.17, 1.39 or 1.43. Typically, the dry reformer operates with a H2/CO molar ratio of about 1.13. With a larger H2/CO molar ratio, however, the carbon dioxide requirement of the dry reformer decreases. In order to balance the amount of carbon dioxide present from separating the carbon dioxide from the flue gas and from the raw synthesis gas against the necessary requirement, it is preferred according to the invention to set the molar ratio (H 2 /CO) to the existing amount of separated CO 2 .

According to a particularly preferred embodiment of the present invention, it is provided that the system includes a complete water desalination device in which fresh water is desalinated and degassed in such a way that the water produced has a sufficiently high purity for the electrolysis of water. The complete water desalination device therefore preferably comprises a fresh water supply line and/or preferably a supply line for waste water produced in the plant, which has particularly preferably previously been cleaned of hydrocarbons, and a discharge line for desalinated water, the discharge line for desalinated water being connected to the water supply line of the electrolysis device. Particular preference is given to all of the fresh water or all or at least almost all of it, ie preferably more than 50% by weight, particularly preferably more than 80% by weight, very particularly preferably more than 90% by weight and most preferably all of it Process water produced in the plant, which has particularly preferably been cleaned beforehand, is fed to the water desalination device. Good results are achieved in particular if the desalination device is designed in such a way that the fresh water supplied is desalinated and degassed to such an extent that its conductivity is less than 20 pS/cm, preferably less than 10 pS/cm, particularly preferably less than 5 pS/cm and most preferably at most 2 pS/cm. For this purpose, the full desalination device preferably has one or more initial and cation exchangers and a membrane device for degassing. During degassing, carbon dioxide and oxygen are separated from the water. The regeneration of the initial and cation exchangers is preferably carried out using caustic soda or hydrochloric acid. The resulting waste water has approximately 6 times the ion concentration of the water before it is fed into the desalination facility and can be fed to a municipal waste water plant as neutral waste water due to the simultaneous regeneration of the pre- and cation exchanger.

In a development of the idea of the invention, it is proposed that the system includes a water purification device in which the process water occurring in the system is cleaned in such a way that it can be circulated. This reduces the fresh water requirement of the system to a minimum. In this embodiment, the plant preferably has a water supply line leading from the refining facility to the water purification facility and/or a water supply line leading from the Fischer-Tropsch facility to the water purification facility and/or a water supply line leading from the synthesis gas production facility to the water purification facility and/or a water supply line leading from the Carbon dioxide compression device leading to the water purification device water supply line respectively for cleaning process water occurring therein. In this embodiment, the plant preferably has a water supply line leading from the refining facility to the water purification facility and a water supply line leading from the Fischer-Tropsch facility to the water purification facility and a water supply line leading from the synthesis gas production facility to the water purification facility and preferably also one from the carbon dioxide compression facility to the water purification facility leading water supply line respectively for cleaning process water occurring therein. The water purification device can have, for example, one or more steam stripping units in which at least 95% of all hydrocarbons can be separated by steam stripping.

According to a particularly preferred embodiment of the present invention, the water purification device comprises an anaerobic reactor. In an anaerobic water purification reactor, the water to be purified is brought into contact with anaerobic microorganisms, which primarily break down the organic impurities contained in the water into carbon dioxide and methane.

In contrast to aerobic water purification, anaerobic water purification does not require oxygen to be introduced into the bioreactor, which requires a great deal of energy. Depending on the type and form of the biomass used, the reactors for anaerobic water purification are divided into contact sludge reactors, UASB reactors, EGSB reactors, fixed bed reactors and fluidized bed reactors. While the microorganisms in fixed-bed reactors adhere to stationary carrier materials and the microorganisms in fluidized-bed reactors to small, freely movable carrier material, the microorganisms in UASB and EGSB reactors are used in the form of so-called pellets. A particular advantage of using an anaerobic reactor as a water purification device in the plant according to the invention is that the process wastewater from the Fischer-Tropsch synthesis contains a wide variety of hydrocarbons, such as alcohols, aldehydes, carboxylic acids and the like, which cannot be removed via other water purification processes, such as a steam stripper , can be removed. Consequently, the water purification by an anaerobic reactor allows the water to be purified in such a way that it can be used in the plant, possibly after desalination in the preferred full water desalination device, for example in the electrolysis device. In addition, the water cleaned and desalinated/degassed in this way can be used as boiler storage water. This drastically reduces the need for fresh water, or even none at all Fresh water required. Finally, the biogas formed in the anaerobic reactor of the water purification facility, which consists primarily of carbon dioxide and methane, can be routed via a gas return line from the water purification facility to the heat generation section of the syngas production facility, where it acts as a fuel.

The water purification device is preferably connected to the water demineralization device via a line, so that water cleaned in the water purification device can be fed into the water demineralization device. In this way, the amount of desalinated and degassed water can be flexibly adapted to the needs, especially for the electrolysis device.

According to a further, particularly preferred embodiment of the present invention, the water purification device is connected directly or indirectly to the supply line for water of the synthesis gas production device in order to be able to supply purified process water as educt to the synthesis gas production device.

In this embodiment of the present invention, an evaporation device is preferably connected downstream of the water purification device, with the evaporation device being connected to the water purification device via a line and to the supply line for water of the synthesis gas production device for supplying water in the form of steam to the synthesis gas production device.

In addition, it is preferred that the plant comprises a control device which controls the amount of water purified in the water purification device fed into the reaction section of the synthesis gas production device in such a way that no fresh water is fed to the synthesis gas production device got to. This contributes to minimizing the fresh water requirement when operating the system according to the invention.

In a further development of the idea of the invention, it is proposed that the plant according to the invention also has a methane steam reformer as a second synthesis gas production device for producing a raw synthesis gas comprising hydrogen and carbon monoxide from methane, water and hydrogen. The methane steam reformer is preferably connected in parallel to the (first) synthesis gas production facility, which is particularly preferably designed as a dry reformer, with the raw synthesis gases produced in the two synthesis gas production facilities being mixed with one another before the raw synthesis gas mixture produced in this way is sent to the separation facility for separating carbon dioxide from the raw synthesis gas is supplied. An advantage of this embodiment is that the methane steam reformer yields raw syngas with a higher H2/CO molar ratio than the dry reformer. Consequently, the raw synthesis gas mixture of the raw synthesis gas produced in the dry reformer and the raw synthesis gas produced in the methane steam reformer has a higher H2/CO molar ratio than the raw synthesis gas produced in the dry reformer, so that in this embodiment with the combined use of a dry reformer and a Methane-steam reformers require less hydrogen or no hydrogen from the electrolysis device to set the desired H2/CO molar ratio in the raw synthesis gas fed to the separating device than when the dry reformer is used alone. The methane steam reformer preferably has a hydrogen supply line, a methane supply line, a water (steam) supply line, a discharge line for raw synthesis gas and a discharge line for water, the hydrogen supply line being connected to the hydrogen discharge line of the electrolysis device, the discharge line for raw synthesis gas being connected to the discharge line for raw synthesis gas is connected to the (first) synthesis gas production facility and preferably the discharge line for water is connected to the water purification device. The methane steam reformer is preferably completely electrically heated solely by means of induction, ie no carbon dioxide is emitted as a result of the inductive heating of the methane steam reformer. The methane steam reformer is preferably operable at low to moderate pressures of 1 to 20 bar, such as 10 to 15 bar, and reaction temperatures of up to 1,500° C., such as 1,000 to 1,200° C., in order to achieve a high yield To achieve synthesis gas (H2/CO) with the lowest possible carbon dioxide content. The carbon dioxide quantities from the heating of the dry reformer and from the process of the methane steam reformer are completely returned to the dry reformer, so that a completely carbon dioxide emission-free plant operation is possible. In order to absorb these amounts of carbon dioxide and to achieve the best possible H2/CO ratio of about 2 before the Fischer-Tropsch synthesis, a ratio between the dry reformer and the methane steam reformer of 30 to 60% to 40 to 65% is preferred. Based on the methane input, an H2/CO ratio in the raw synthesis gas produced in the dry reformer of 1.13 to 1.80 and preferably from 1.15 to 1.20, such as 1.17, and an H2/CO ratio in that raw synthesis gas produced in the methane steam reformer from 3.20 to 3.60 adjusted as 3.43. The ratio between the dry reformer and the methane-steam reformer is preferably adjusted via the amount of methane added to the methane-steam reformer, with the H2/CO ratio in the dry reformer being adjusted via the amount of carbon dioxide supplied and the H2/CO ratio in the methane-steam reformer via the amount of steam supplied takes place.

To separate the carbon dioxide from the raw synthesis gas, it is proposed in a development of the inventive concept that the corresponding separation device b) has an amine scrubber for separating carbon dioxide from the raw synthesis gas by absorption. In the amine scrubber, carbon dioxide is removed from the raw synthesis gas by absorption with at least one absorbent, which preferably consists of an amine compound such as monoethanolamine and/or diglycolamine and water, is separated and then returned directly or indirectly (e.g. via a desorber and a compressor) to the synthesis gas production facility.

Good results are achieved in particular if the separating device b) is followed by a compression device for compressing the synthesis gas to the pressure required in the Fischer-Tropsch synthesis, the compression device being connected to the separating device via a line and to the Fischer-Tropsch -Device is connected via a synthesis gas supply line. In the preferred compressor, the remaining synthesis gas is compressed to the pressure required in the Fischer-Tropsch synthesis before the synthesis gas compressed in this way is fed to the Fischer-Tropsch device. The synthesis gas fed to the Fischer-Tropsch device preferably contains 80 to 90% by mass of carbon monoxide and 10 to 15% by mass of hydrogen.

Hydrogen is preferably fed to the compression device in order to adjust the HiVCO mole ratio of the synthesis gas fed to the Fischer-Tropsch device to an optimum value. For this purpose, the compression device preferably has a hydrogen supply line which is connected to the electrolysis device. For example, the synthesis gas in the compression device is compressed to 30 to 60 bar, preferably 40 to 50 bar, such as about 45 bar, and adjusted to a temperature of 100 to 140°C, preferably 110 to 130°C, such as about 120°C . After the compression device, the synthesis gas is preferably also cleaned by means of adsorbents in a 3-stage process for cleaning off halogen, oxygen and sulfur compounds in the ppb range, which represent catalyst poisons for the Fischer-Tropsch synthesis. The purification takes place in three consecutive stages for the halogen, oxygen and sulfur separation in appropriate fixed-bed filters. actors. An activated carbon bed serves as an additional safety filter. The synthesis gas is fed to the fine cleaning system at a pressure of approx. 45 bar and a temperature of approx. 120°C. An alumina/sodium oxide adsorbent acts as a halogen scavenger. The synthesis gas freed from halogen is further heated under temperature control to the operating temperatures of the downstream reactors of 140 to 150°C. This heating takes place by applying medium-pressure steam to the synthesis gas preheater. An alumina/palladium oxide adsorbent is used in the oxygen purge reactor and acts as an oxygen scavenger. The synthesis gas, which is still contaminated with traces of sulfur compounds, flows through different adsorbent layers in the sulfur discharge reactor, namely first a layer with a zinc oxide/aluminum oxide/sodium oxide adsorbent, in which the main desulfurization takes place, and then a further safety layer with zinc oxide/copper oxide adsorbent, in which optionally residual sulfur is bound. An additional activated carbon bed serves as a further filter for further impurities.

In order to set the optimal H2/CO molar ratio of the synthesis gas fed to the Fischer-Tropsch device, it is preferred that the system comprises a control device which controls the amount of hydrogen fed into the compression device in such a way that the H2/CO molar ratio in the synthesis gas discharged from the compression device, which is fed to the Fischer-Tropsch device via the synthesis gas feed line, is more than 2.0.

The synthesis gas is then converted into hydrocarbons in the Fischer-Tropsch facility. The Fischer-Tropsch synthesis is preferably carried out in a reactor with a catalyst at a temperature of from 170 to 270°C, preferably from 190 to 250°C and most preferably from 210 to 230°C, such as 220°C. Particularly suitable catalysts are those selected from the group consisting of cobalt catalysts, such as preferably Co/MMT (Mont- morillonite) or C0/S1O2. The Fischer-Tropsch synthesis is preferably carried out in one or more tube bundle apparatus, the catalyst being located in the tubes, whereas the cooling medium, preferably boiler feed water, is conducted in the jacket space. The Fischer-Tropsch device preferably comprises one or two reactors in order to be able to carry out the Fischer-Tropsch synthesis in one or two stages. For reasons of cost, the Fischer-Tropsch synthesis is preferably carried out in one stage. For example, the Fischer-Tropsch synthesis is carried out at a pressure of 25 to 35 bar or preferably also at a higher pressure of, for example, 45 bar. The higher the pressure, the smaller the reactors can be built. The Fischer-Tropsch synthesis is preferably carried out in such a way that a carbon monoxide conversion of 92% or more is achieved. In the Fischer-Tropsch synthesis, condensates and waxes are obtained as liquid products, which are fed to the downstream refining facility. The cooling of the very strong exothermic process of the Fischer-Tropsch synthesis takes place via boiler feed water, which is conducted via a corresponding line from the water demineralization device and/or the water purification device and preferably from the water demineralization device into the Fischer-Tropsch device and is evaporated to cool the reactors . At least a large part of the vapor produced in the Fischer-Tropsch synthesis is preferably fed via a steam return line to the synthesis gas production device. The excess steam from the Fischer-Tropsch facility is preferably used for heating in the other plant units, so that no external steam is required.

In the refining facility, the products of the Fischer-Tropsch synthesis are refined into synthetic fuels, in particular aircraft turbine fuel (kerosene), diesel and/or naphtha, such as kerosene (SAF - "Sustainable Aviation Fuet"), naphtha and/or light naphtha. For the production of industrially usable kerosene, diesel and naphtha, it is necessary to convert the paraffinic product of the Fischer-Tropsch synthesis by hydro-isomerization and hydrocracking (iso-hydrocracking) in such a way that a high-quality jet turbine fuel with the required cold properties (preferably with a temperature limit of Filterability corresponding to "Cold Filtration Plugging Point (CFPP) of maximum -40°C) is produced. The heavy products are recirculated in the iso-hydrocracker reactor in such a way that only kerosene and naphtha are formed as products. The resulting light gases are routed as fuel to the heat generation section of the syngas manufacturing facility.

Therefore, it is preferred that the refining facility comprises one or more iso-hydrocracker reactors, preferably with a noble metal catalyst, such as preferably a platinum or palladium catalyst. Particularly preferred are noble metal catalysts that do not require sulfidation, as this avoids contamination of the reaction products with sulphur-containing components, which in turn allows the process gas produced during iso-hydrocracking, as well as the steam produced, to be recycled to the heat generation section of the syngas production facility. Iso-hydrocracking is a catalytic reaction in which, in particular, long-chain paraffinic hydrocarbons are produced into short-chain isomers with improved cold properties for the production of kerosene. The catalytic reaction preferably takes place in bed reactors which are cooled with hydrogen to ensure the maximum bed temperature. For example, these are operated at a pressure of at least 70 bar.

Furthermore, it is preferred that the refining facility comprises one or more hydrogen strippers for separating light hydrocarbons (namely C 1 to C 4 hydrocarbons). Finally, the refining facility includes preferably one or more distillation columns for separating the synthetic fuels into individual fractions such as jet fuel and diesel, jet fuel and naphtha, jet fuel, naphtha and diesel, or the like.

The hydrogen required for the operation of the iso-hydrocracker reactor and for the hydrogen stripper is fed to the refining device, as described above, preferably from the electrolysis device.

As described above, the process water generated in the Fischer-Tropsch synthesis, which has a high proportion of hydrocarbons, such as alcohols, aldehydes, carboxylic acids etc. in particular, with a chemical oxygen demand (COD) of approx. 40,000 mg/l, is preferred for the water purification device fed in to be cleaned there so that it can be circulated as process water.

In a development of the idea of the invention, it is proposed that the system according to the invention also includes a methanation device for converting carbon dioxide and hydrogen into methane and water. The methanation device preferably has a carbon dioxide supply line, a hydrogen supply line, which is preferably connected to the hydrogen discharge line of the electrolysis device, a methane discharge line and a water discharge line, the methane discharge line being connected to the methane supply line of the synthesis gas production device and preferably the water discharge line of the methanation device being connected to the water purification device . A partial line can also lead from the methane discharge line into the supply line for fuel in the synthesis gas production facility. Since both the carbon dioxide and the hydrogen are produced during the operation of the plant, in this embodiment the for the (first) synthesis gas production device, which is particularly preferably a dry reformer, the methane required can be generated inexpensively in the plant itself and does not have to be supplied from an external source. The reaction is very highly exothermic and also produces significant amounts of low and medium pressure steam which can be used in the plant. Due to the existing electrolysis device, the system concept according to the invention makes it possible to integrate a methanation device into the system without any problems, especially since the water produced during the methanation can be cleaned in the preferred water treatment device and thus fully desalinated in the preferred full desalination device and thus reused as starting material in the electrolysis or as boiler feed water can be. The methanation device is preferably a tube bundle reactor equipped with a nickel catalyst.

According to a first preferred embodiment of the present invention, the plant has a separating device ei) for separating carbon dioxide from the flue gas discharged from the synthesis gas production device via the discharge line for flue gas. The separation device preferably comprises an amine scrubber for separating carbon dioxide from the flue gas, with carbon dioxide being separated from the raw synthesis gas in the amine scrubber by absorption with at least one absorbent, which preferably consists of one or more amine compounds. The carbon dioxide separated off in this way can be fed directly to the synthesis gas production facility. However, it is preferred that the carbon dioxide separated in this way from the separating device - particularly preferably together with the carbon dioxide separated from the raw synthesis gas in the separating device b) - is first fed via a corresponding line to a carbon dioxide compression device, in which the carbon dioxide is compressed to a pressure of 25 to 40 bar and preferably from 30 to 35 bar before the carbon dioxide gas thus compressed is recycled to the synthesis gas production facility. According to a second preferred embodiment of the present invention, the flue gas produced in the synthesis gas production facility is completely returned—directly or indirectly—to the synthesis gas production facility. This embodiment is particularly useful when the heat generation section of the synthesis gas production device is supplied exclusively or at least primarily with oxygen from the electrolysis via the supply line for oxygen-containing gas, so that the flue gas does not contain any inert gases, such as nitrogen in particular, as is the case would be if air would be supplied for the . In this embodiment, the plant preferably has a flue gas recirculation line connected to the flue gas discharge line of the synthesis gas production facility, the flue gas recirculation line—and particularly preferably also the carbon dioxide discharge line of the separating device b) for separating carbon dioxide from the raw synthesis gas produced in the synthesis gas production facility—either directly with one of the at least one supply line for carbon dioxide of the synthesis gas production device are connected, or both lines are first fed to a carbon dioxide compression device in which the carbon dioxide is compressed to the pressure described above as preferred before the carbon dioxide gas compressed in this way is returned to the synthesis gas production device.

According to a third preferred embodiment of the present invention, the two aforementioned embodiments are combined, ie part of the flue gas is fed into a separator for separating carbon dioxide, in which the carbon dioxide is separated from the flue gas, whereas the rest of the flue gas without carbon dioxide separation together with the carbon dioxide separated off in the two separating devices is returned directly to the synthesis gas production device or is first fed to a carbon dioxide compression device in which the gas mixture is compressed to the pressure described above as being preferred before the gas mixture compressed in this way is returned to the synthesis gas production device. This embodiment is also particularly useful if the heat generation section of the synthesis gas production facility is supplied exclusively or at least primarily with oxygen from the electrolysis via the supply line for oxygen-containing gas, so that the flue gas does not contain any inert gases, such as nitrogen in particular, as is required by the Case would be if air would be supplied for that.

Another subject matter of the present patent application is a method for producing synthetic fuels, in particular jet turbine fuel (kerosene), naphtha and/or diesel, which is carried out in a previously described plant.

As explained above, the process according to the invention can be operated without removing carbon dioxide or without emitting carbon dioxide. For this reason it is preferred that no carbon dioxide is discharged in the process.

In a further development of the inventive idea, it is proposed that gas generated in the Fischer-Tropsch device, gas generated in the refining device and part of the synthetic fuels produced in the refining device are fed as fuel into the heat generation section of the synthesis gas production device, with the method preferably is controlled in such a way that no external fuel has to or is supplied to the synthesis gas production facility and preferably to the entire plant.

According to the invention, the system includes an electrolysis device for separating water into hydrogen and oxygen. According to the invention, at least part of the oxygen generated in the electrolysis device via the line for Oxygen-containing gas fed into the heat generation section of the synthesis gas production facility. In addition, at least part of the hydrogen produced in the electrolysis device can be fed to the reaction section of the synthesis gas production facility for desulfurization of the biomethane and in particular also for adjusting the H2/CO molar ratio in the raw synthesis gas produced in the reaction section in the synthesis gas production facility. The H2/CO molar ratio in the raw synthesis gas produced in the synthesis gas production facility is preferably set to 1.13 to 1.80 and preferably 1.15 to 1.50, such as 1.17, 1.39 and 1.43.

Good results are obtained in particular if the separating device b) is followed by a compression device for compressing the gas to the pressure required in the Fischer-Tropsch synthesis, with part of the hydrogen produced in the electrolysis device being fed to the compression device, with the amount of in the hydrogen sent to the compressor is controlled such that the H2/CO molar ratio in the synthesis gas discharged from the compressor and fed to the Fischer-Tropsch device is greater than 2.0.

In the method according to the invention, part of the hydrogen produced in the electrolysis device of the Fischer-Tropsch device for generating the required H2/CO ratio of more than 2.0 in the Fischer-Tropsch-Tropsch device, part of the hydrogen produced in the electrolysis device is fed to the refining facility and part of the hydrogen produced in the electrolysis device is fed to the synthesis gas compression device.

In order to reduce the required amount of combustion air to the synthesis gas production facility as much as possible, it is provided according to the invention that at least part of the oxygen generated during the electrolysis is fed into the synthesis gas production facility. Preferably 1 to 90% by volume, preferably 5 to 60% by volume, particularly preferably 10 to 50% by volume, very particularly preferably 20 to 40% by volume and most preferably 25 to 35% by volume of the oxygen required in the synthesis gas production facility is conducted from the electrolysis facility into the synthesis gas production facility. The remainder of the oxygen required in the synthesis gas production facility is preferably supplied to the synthesis gas production facility in the form of air. As further explained above, in large-scale applications it is not possible for the oxygen content of the combustion mixture to be higher.

In addition, it is preferred that the plant comprises a water purification facility to which is supplied water produced by the refining facility therein, water produced therein by the Fischer-Tropsch facility, and water from the synthesis gas production facility, the amount being purified in the water purification facility Water is controlled so that it is at least sufficient to cover the entire water requirement of the synthesis gas production facility. The water purification particularly preferably comprises at least one purification stage in an anaerobic reactor. The biogas formed in the anaerobic reactor of the water purification facility, which consists primarily of carbon dioxide and methane, can be conducted via a gas return line from the water purification facility into the heat generation section of the synthesis gas production facility in order to act as fuel in the heat generation section of the synthesis gas production facility.

Furthermore, it is preferred that the method is carried out in a system which includes a water demineralization device in which fresh water is desalinated and degassed in such a way that the water produced is one for the electrolysis of Water has sufficiently high purity. In the method according to the invention, the water in the desalination device is preferably purified to water with a conductivity of less than 20 pS/cm, preferably less than 10 pS/cm, particularly preferably less than 5 pS/cm and most preferably at most 2 gS/cm.

In a development of the idea of the invention, it is proposed that dry reforming be carried out in the synthesis gas production device, in which a nickel oxide catalyst is used. In addition, it is preferred that the dry reforming is operated at a pressure of 10 to 50 bar and a temperature of 700 to 1,200°C.

According to a particularly preferred embodiment of the present invention, the process also includes methane steam reforming. In methane steam reforming, a raw synthesis gas comprising hydrogen and carbon monoxide is preferably produced from methane, water and hydrogen, with the methane steam reformer being supplied with water (steam), methane and hydrogen from the electrolysis device, and raw synthesis gas and water being supplied from the methane steam reformer are discharged, the raw synthesis gas being fed to the separating device and preferably the water being fed to the water purification device. The methane steam reforming is preferably carried out at a pressure of 1 to 20 bar, preferably 5 to 15 bar and particularly preferably 10 to 15 bar and at a temperature of 800 to 1,500 C., preferably 900 to 1,300° C. and particularly preferably 1 . 000 to 1,200°C, such as at a pressure of about 12 bar and a temperature of about 1,100°C. The basic reaction is strongly endothermic, but the formation of CO2 cannot be completely ruled out. Preferably, a nickel catalyst is used for the methane steam reforming and the methane steam reforming is supplied methane in an upstream hydrogenation to remove the sulfur components with hydrogen, which preferably comes from the electrolysis device, hydrogenated, the hydrogenated sulfur components from separated from the methane. In the methane steam reformer, the syngas is preferably cooled by feedstock preheating and subsequent intermediate pressure steam generation. The steam produced can be used entirely as steam for the methane steam reformer in conjunction with the medium pressure steam from the dry reformer.

Good results are obtained in particular when dry reforming is carried out in the method in the synthesis gas production facility and the ratio between the dry reformer and the methane steam reformer is adjusted to 30 to 60% to 40 to 65%, based on the methane input. It is also preferred if the raw synthesis gas produced in the dry reformer has an H2/CO ratio of 1.13 to 1.80 and preferably 1.15 to 1.20, such as 1.17, and that produced in the methane steam reformer Raw synthesis gas has a H2/CO ratio of 3.20 to 3.60, such as 3.43.

Furthermore, it is preferred that in the method carbon dioxide and hydrogen supplied from the electrolysis device are converted into methane and water in a methanation device, the methane being fed to the synthesis gas production device and preferably the water being fed to the water purification device. A tube bundle reactor equipped with a nickel catalyst is preferably used as the methanation device. The methanation preferably takes place under a pressure of 10 to 50 bar and more preferably 30 to 40 bar, for example at about 35 bar, and at a temperature of 100 to 500° C., preferably 200 to 400° C. and particularly preferably from 250 to 350°C, such as from about 300°C. The very strongly exothermic reaction is preferably cooled by means of boiler feed water in the shell space of the tube bundle reactor by evaporation to generate low and medium-pressure steam, which can be used in other parts of the plant. The carbon dioxide conversion in the methanation is 80 to 85%, so that carbon dioxide remains in the product, but the (First) synthesis gas production facility or the dry reformer can be supplied without any problems.

In a further development of the idea of the invention, it is proposed that a purge gas flow is derived as fuel gas from the Fischer-Tropsch device. This reliably prevents the accumulation of inert gases such as nitrogen and argon in the synthesis gas production facility and in the Fischer-Tropsch facility.

Finally, it is preferred that the refining facility produces jet fuel, naphtha and/or diesel, and preferably both jet fuel and naphtha. For example, kerosene (SAF - "Sustainable Aviation Fuel"), crude petrol and light petrol are produced in the process according to the invention.

The present invention is described in more detail below with reference to the drawing, in which:

1 shows a schematic view of a for the production of synthetic fuels according to an embodiment.

FIG. 2 shows a schematic view of a synthetic fuel production line according to another embodiment. FIG.

3 shows a schematic view of a for the production of synthetic fuels according to a further embodiment.

The plant 10 shown in Figure 1 for the production of synthetic fuels includes: a) a synthesis gas production facility 12 for producing a raw synthesis gas comprising carbon monoxide, hydrogen and carbon dioxide from methane, water and carbon dioxide, the synthesis gas production facility 12 having at least one reaction section in which methane, water and carbon dioxide react to form the raw synthesis gas, and at least one heat generation section in which the heat required for the reaction of methane, water and carbon dioxide to form the raw synthesis gas is generated by burning fuel to form flue gas, the reaction section having a supply line 14 for methane, a supply line 16 for water, at least one supply line 18 for carbon dioxide and a discharge line 20 for raw synthesis gas and the heat generation section comprises a supply line 22 for fuel, a supply line 24 for oxygen-containing gas and a discharge line 26 for flue gas, b) a separator 28 for separating carbon dioxide from the in de r synthesis gas production device 12 with a discharge line 30 for carbon dioxide and a discharge line 32 for synthesis gas, c) a Fischer-Tropsch device 34 for the production of hydrocarbons by a Fischer-Tropsch process from the synthesis gas, from which carbon dioxide is separated in the separating device 28 and d) a refining device 36 for refining the hydrocarbons produced in the Fischer-Tropsch device 34 into the synthetic fuels, the system 10 further comprising: ei) a separating device 38 for separating carbon dioxide from the flue gas via the discharge line 26 from the synthesis gas production facility discharged flue gas, the separator 38 having a discharge line 40 for carbon dioxide, the discharge line 40 for carbon dioxide of the separator 38 for separating carbon dioxide from the The flue gas discharged via the discharge line 26 for flue gas from the synthesis gas production facility 12 and the discharge line 30 for carbon dioxide of the separating device 28 for separating carbon dioxide from the crude synthesis gas produced in the synthesis gas production facility 12 are connected to a carbon dioxide compression facility 42, which has a discharge line which is connected to the Supply line 18 for carbon dioxide of the synthesis gas production device 12 is connected.

The separating device 28 is followed by a synthesis gas compression device 43 for compressing the synthesis gas to the pressure required in the Fischer-Tropsch synthesis. The synthesis gas compression device 43 is connected to the separating device 28 via the discharge line 32 for synthesis gas and to the Fischer-Tropsch device 34 via a synthesis gas feed line 44 . The Fischer-Tropsch device 34 in turn is connected to the refining device 36 via the line 46, the refining device 36 having two product discharge lines 48', 48''.

A gas return line 50 leads from the Fischer-Tropsch device 34, a methane supply line 15 leads from the outside and a gas return line 52, a fuel return line 54 and a biogas return line 51 lead from the refining device 36 into the supply line 22 for fuel of the synthesis gas production device 12.

The system 10 also includes an electrolysis device 56 for generating hydrogen and oxygen from water, the electrolysis device 56 having a water supply line 58 , an oxygen discharge line 60 and a hydrogen discharge line 62 . A line 63 leads from the hydrogen discharge line 62 to the synthesis gas production device 12, a line 64 to the Fischer-Tropsch device 34, a line 65 to the synthesis gas compression device 43 and a line 66 to the refining device 36. From the Oxygen removal line 60 feeds an oxygen line 68 into the oxygen-containing gas feed line 24 of the syngas producer 12 and an oxygen product line 69 from the plant 10. Also feeding into the oxygen-containing gas feed line 24 of the syngas producer 12 is a combustion air feed line 25.

In addition, the system 10 includes a water desalination device 70 which has a fresh water supply line 72 and a discharge line 74 for fully desalinated water, the discharge line 74 for fully desalinated water being connected to the water supply line 58 of the electrolysis device 56 .

In addition, the system 10 includes a water purification device 76, in which process water occurring in the system is purified in such a way that it can be circulated. The water purification device 76 includes an anaerobic reactor in which the water to be purified is brought into contact with anaerobic microorganisms, which break down the organic impurities contained in the water primarily into carbon dioxide and methane. A process water supply line 78 coming from the Fischer-Tropsch facility 34, a process water supply line 80 coming from the refining facility 36, a process water supply line 81 coming from the carbon dioxide compression facility 42 and a process water supply line 82 coming from the synthesis gas production facility 12 lead to the water purification facility 76. The system also includes 10 an evaporation device 84, the evaporation device 84 being connected to the water purification device 76 via a process water line 86. In addition, the evaporation device 84 is connected to the supply line 16 for water vapor of the synthesis gas production device 12 via a line. Finally, a process water line 88 leads from the water purification device 76 to the water demineralization device 70 and a biogas return line 51 to the heat generation waste Section of the synthesis gas production device 12 for the biogas formed in the anaerobic reactor of the water purification device 76, which consists primarily of carbon dioxide and methane, for example in a ratio of about 1:1.

Finally, the separating device 38 for separating off the flue gas of the plant 10 includes a supply line 27 for boiler feed water, a discharge line 41 for nitrogen and a process water discharge line 83 which opens into the water purification device 76 . The water desalination device 70 also includes a supply line 71 for boiler condensate, a discharge line 73 for boiler feed water and a waste water discharge line 75 from the system 10.

During the operation of the plant 10, the reaction section of the synthesis gas production device 12 is supplied with methane via the supply line 14, water (steam) via the supply line 16 and carbon dioxide via the supply line 18, which react in the reaction section of the synthesis gas production device 12 to form raw synthesis gas. The energy or heat necessary for this highly endothermic reaction is generated by burning fuel in the heat generation section of the syngas manufacturing facility. For this purpose, fuel is fed to the heat generation section of the synthesis gas production device 12 via the feed line 22 and an oxygen-containing gas is fed via the feed line 24 . The fuel comes from waste gases or fuel produced in plant 10, namely from the waste gas from the Fischer-Tropsch facility 34, which is fed to the synthesis gas production facility 12 via the gas return line 50, from the waste gas from the refining facility 36, which is fed to the synthesis gas production facility 12 via the Gas return line 52 is supplied, from synthetic fuel (light petrol), which is fed to the synthesis gas production device 12 via the fuel return line 54, and from biogas, which is fed to the synthesis gas production device 12 via the biogas return line 51 from the water purification device 76. the Combustion of the fuel in the heat generation section of the synthesis gas production device 12 takes place, for example, at 1.5 bar and a temperature of 1,100°C. The raw synthesis gas generated in the reaction section of the synthesis gas production facility 12 is drawn off via the discharge line 20 and fed to the separation device 28, whereas the flue gas produced by combustion in the heat generation section of the synthesis gas production facility 12 is drawn off via the discharge line 26 and fed to the separation device 38. In the separating device 28 carbon dioxide is separated from the raw synthesis gas, which is conducted via the line 30 into the carbon dioxide compression device 42 . In addition, carbon dioxide is separated from the flue gas in the separating device 38 and is conducted via the line 40 into the carbon dioxide compression device. In the carbon dioxide compression device 42, the carbon dioxide is compressed to, for example, 32.5 bar before the compressed carbon dioxide is fed back to the synthesis gas production device 12 via the line 18. Carbon dioxide emissions can be dispensed with as a result of this procedure, since the carbon dioxide produced by the combustion of the fuel is used to replace the carbon dioxide consumed in the synthesis gas production. For this reason, the process according to the invention is carbon dioxide-neutral. In addition, as a result of this procedure, the supply of fuel from the outside can be dispensed with completely or at least almost completely.

The synthesis gas freed from carbon dioxide in the separating device 28 is fed via the line 32 to the synthesis gas compression device 43 , in which hydrogen is also fed in from the electrolysis device 56 via the line 65 . In the compression device, the synthesis gas is compressed to 42.5 bar, for example, and adjusted to a temperature of 120.degree. Furthermore, after the compression device, the synthesis gas is also cleaned with appropriate adsorbents, by means of which halogens, sulphur, nitrogen, oxygen, metals and other impurities are separated from the synthesis gas will. The amount of hydrogen fed to syngas compressor 43 is controlled so that the H2/CO mole ratio of the syngas is greater than 2.0. This synthesis gas is fed via line 44 into the Fischer-Tropsch device 34, in which the synthesis gas is converted into predominantly normal paraffinic hydrocarbons. These hydrocarbons are sent via line 46 to refiner 36 where they are hydro-isomerized and hydrocracked (iso-hydrocracked) to produce synthetic feedstocks which are then separated in the hydrogen stripper and in the one or more distillation columns of refiner 36 be separated into the fractions of light petrol, petroleum and kerosene (SAF- "Sustainable Aviation Fuel'), from which petroleum and kerosene are removed via lines 48 (petrol) and 48' (kerosene) from system 10 and from which light petrol via the Fuel return line 54 and ultimately via the fuel supply line 22 of the synthesis gas production device 12 is supplied. Water occurring in the Fischer-Tropsch device 34, in the refining unit 36, in the carbon dioxide compression device 42, in the separating device 38 for carbon dioxide and in the synthesis gas production device 12 is conducted via the process water lines 78, 80, 81, 82, 83 into the waste water purification device 76 , in which the waste water is cleaned by anaerobic microorganisms. A portion of the cleaned process water is fed via the process water line 86 to the evaporation device 84 in which the process water is completely vaporized, with the water vapor thus generated being fed to the synthesis gas production device 12 via the line 16 . The other part of the cleaned process water is fed to the complete water desalination device 70 via the process water line 88 .

The pure water required for the electrolysis device 56 is produced by the complete desalination of fresh water and purified process water in the water demineralization device 70 and is fed to the electrolysis device 56 via the line 58 . The hydrogen generated in the electrolysis device 56 is on the Lines 62, 63, 64, 65, 66 of the synthesis gas production device 12, the Fischer-Tropsch device 34, the synthesis gas compression device 43 and the refining device 36 are fed. A portion of the oxygen produced in the electrolyzer 56 is conducted via line 68 together with air supplied via line 25 as an oxygen-containing gas into the heat generating section of the synthesis gas production facility 12, while the other part of the oxygen produced in the electrolyzer 56 is discharged via line 69 from the Appendix 10 is discharged.

The system 10 shown in FIG. 2 corresponds to that shown in FIG. 1, except that the system 10 shown in FIG. 2 additionally includes a methanation device 11 for converting hydrogen and carbon dioxide into methane and water. The methanation device 11 has a carbon dioxide feed line 19, a hydrogen feed line 67, which is connected to the hydrogen discharge line 62 of the electrolysis device 56, a methane discharge line 17 and a water discharge line 87, the methane discharge line 17 being connected to the methane feed line 14 of the synthesis gas production device 12 and the Water discharge line 87 of the methanation device 11 is connected to the water purification device 76 . A partial line 15' also leads from the methane discharge line 1722 into the supply line for fuel in the synthesis gas production facility 12. Since both the carbon dioxide and the hydrogen are produced during the operation of the plant 10, in this embodiment this can be done for the (first) synthesis gas production facility 12, which is a Dry reformer is required methane be generated inexpensively in the plant 10 itself and does not have to be supplied from an external source. The reaction is very highly exothermic and also produces significant amounts of low and medium pressure steam which can be used in the plant. Due to the existing electrolysis device 56, the system concept according to the invention makes it possible to integrate the methanation device 11 into the system 10 without any problems. bind, especially since the water produced during the methanation can be cleaned in the water treatment device 76 and thus fully desalinated in the full desalination device 70 and can thus be reused as starting material in the electrolysis or as boiler feed water.

The system 10 shown in Figure 3 corresponds to that shown in Figure 1, except that the system 10 shown in Figure 3 also has a methane steam reformer 31 as a second synthesis gas production device for producing a carbon monoxide and hydrogen-comprising raw synthesis gas from methane, water and hydrogen having. The methane steam reformer 31 is preferably connected in parallel to the (first) synthesis gas production facility 12, which is designed as a dry reformer, with the raw synthesis gases produced in the two synthesis gas production facilities 12, 31 being mixed with one another before the raw synthesis gas mixture produced in this way is sent to the separating facility 28 for separating off Carbon dioxide is supplied from the raw synthesis gas. For this purpose, the methane steam reformer 31 has a hydrogen supply line 61, a methane supply line 13, a water (steam) supply line 23, a discharge line 21 for raw synthesis gas and a discharge line 85 for process water, with the hydrogen supply line 61 being connected to the hydrogen discharge line 62 of the electrolysis device 56. the discharge line 21 for raw synthesis gas is connected to the discharge line 20 for raw synthesis gas of the (first) synthesis gas production device 12 to the raw synthesis gas supply line 29 of the separating device 28 and the discharge line 85 for water is connected to the water purification device 76. The methane steam reformer 31 can be completely electrically heated solely by means of induction, ie no carbon dioxide is emitted as a result of the inductive heating of the methane steam reformer 31 . The methane steam reformer is operated at low to moderate pressures of 1 to 20 bar, such as 10 to 15 bar, and reaction temperatures of up to 1500°C, such as 1000 to 1200°C. An advantage of this embodiment is that the methane steam reformer 31 produces a raw synthesis gas with a higher H2/CO molar ratio than the dry reformer 12. Consequently, the raw synthesis gas mixture of the raw synthesis gas produced in the dry reformer 12 and the raw synthesis gas produced in the methane steam reformer 31 has a higher H2/CO molar ratio than the raw synthesis gas produced in the dry reformer 12, so that in this embodiment - in comparison to the sole use of the dry reformer 12 - with the combined use of a dry reformer 12 and a methane steam reformer 31, no hydrogen from the electrolysis device 56 is required to set the desired H2/CO molar ratio in the raw synthesis gas fed to the separating device 28. Finally, the system 10 also includes a discharge line 55 for fuel gases.

The present invention is described below using an example that is illustrative but not limiting of the invention. example 1

The method according to the invention was simulated in a plant shown in Figure 1 and described above with the process simulation software PRO/II (AVEVA) for the production of 144,456 liters per day of kerosene (SAF - "Sustainable Aviation Fuel) and 42,528 liters per day of crude petrol (naphtha). The following product flows were determined for the individual lines:

example 2

The process according to the invention was carried out in a plant shown in Figure 2 and described above with the process simulation software PRO/II (AVEVA) for the production of 145,827 liters per day of kerosene (SAF - "Sustainable Aviation Fuel") and 42,883 liters per day of crude petrol (naphtha ) simulated. The following product flows were determined for the individual lines:

Example 3

The process according to the invention was carried out in a plant shown in Figure 3 and described above with the process simulation software PRO/II (AVEVA) for the production of 148,096 liters per day of kerosene (SAF, Sustainable Aviation Fuel') and 43,130 liters per day of crude petrol (Naphtha ), as well as from 13,422 liters per day of light liquid hydrocarbons and 20.6 million liters per day of fuel gas are simulated. The following product flows were determined for the individual lines:

reference list

10 Plant for the production of synthetic fuels

11 methanation facility

12 (First) syngas manufacturing facility/dry reformer

13 Methane feed line to the methane steam reformer

14 Methane supply line to the synthesis gas production facility

15 methane feed line

15 branch line into the fuel supply line

16 supply line for steam to the synthesis gas production facility

17 methane discharge line of the methanation facility

18 Carbon dioxide supply line to the synthesis gas production facility

19 Carbon dioxide supply line to methanator

20 discharge line for raw synthesis gas

21 discharge line for raw synthesis gas from the methane steam reformer

22 fuel supply line

23 Methane steam reformer water (steam) feed line

24 Oxygen-containing gas supply line

25 Combustion air supply line

26 flue gas discharge duct

27 Boiler feed water supply line

28 Separator for separating carbon dioxide from raw synthesis gas

29 raw synthesis gas feed line 30 discharge line for carbon dioxide from the raw synthesis gas separator

31 Methane Steam Reformer (Second Syngas Manufacturing Facility)

32 Discharge line for synthesis gas 34 Fischer-T ropsch device 36 Refining device 38 Separation device for separating carbon dioxide from flue gas

40 discharge line for carbon dioxide from the flue gas separator

41 nitrogen discharge line

42 carbon dioxide compression device

43 synthesis gas compression device

44 Syngas feed line to the Fischer-Tropsch facility. 46 Feed line to the refiner

48, 48', 48" product discharge lines

50 Gas return line of the Fischer-Tropsch device

51 Biogas return line to the synthesis gas production facility

52 Refinery gas return line

53 Gas return line for light hydrocarbons

54 fuel return line

55 discharge line for fuel gas

56 Electrolyzer 58 Water supply line of the electrolyzer 60 Oxygen discharge line of the electrolyzer 61 Hydrogen supply line to the methane steam reformer 62 Hydrogen discharge line of the electrolyzer

63 Hydrogen supply line to the synthesis gas production facility

64 Hydrogen feed line to the Fischer-Tropsch facility 65 Hydrogen supply line to the carbon dioxide compressor

66 Hydrogen supply line to refiner

67 Hydrogen supply line to the methanator

68 oxygen line

69 oxygen product line

70 water desalination facility

71 Boiler condensate supply line

72 Fresh water supply line / water discharge line

73 Drain pipe for boiler feed water

74 Discharge line for deionized water

75 discharge line for waste water from the plant

76 water purification device

78 Process water discharge line from the Fischer-Tropsch facility

80 Process water discharge line from refining facility

81 Process water discharge discharge line from carbon dioxide compression facility

82 Process water discharge line from syngas manufacturing facility

83 Process water discharge line from the separation device for separating carbon dioxide

84 evaporation device

85 Methane steam reformer process water supply line

86 Process water supply pipe to the evaporator from the water purification facility

87 Process water discharge line of the methanation facility

88 Process water supply line of the water desalination facility from the water purification facility

Claims

Patent Claims: 1. Plant (10) for the production of synthetic fuels, in particular jet fuel (kerosene), crude petrol and/or diesel, comprising: a) a synthesis gas production facility (12) for producing a carbon monoxide, hydrogen and carbon dioxide-comprising raw synthesis gas from methane, water and carbon dioxide , wherein the synthesis gas production device (12) has at least one reaction section in which methane, water and carbon dioxide react to form the raw synthesis gas, and at least one heat generation section in which the heat required for the reaction of methane and carbon dioxide to form the raw synthesis gas is generated by burning fuel to form flue gas wherein the reaction section comprises a supply line (14) for methane, a supply line (16) for water, at least one supply line (18) for carbon dioxide and a discharge line (20) for raw synthesis gas and the heat generation section comprises a supply line (22) for fuel, a supply line for oxygen-containing gas (24) and a discharge line (26) for flue gas, b) a separating device (28) for separating carbon dioxide from the in the synthesis gas production device (12) produced raw synthesis gas with a discharge line (30) for carbon dioxide and a discharge line ( 32) for synthesis gas, c) a Fischer-Tropsch device (34) for the production of hydrocarbons by a Fischer-Tropsch process from the synthesis gas from which carbon dioxide has been separated in the separator (28), and d) a refining device (36) for refining the hydrocarbons produced in the Fischer-Tropsch device (34) into the synthetic fuels, the system (10) further comprising: ei) a separating device (38) for separating carbon dioxide from the the discharge line (26) for flue gas from the heat generation section of the synthesis gas production device (12) discharged flue gas, the separating device (28) having a discharge line (40) for carbon dioxide, the discharge line (40) for carbon dioxide of the separating device (38) and the discharge line ( 30) for carbon dioxide of the separating device (28) are either connected directly to one of the at least one feed line (18) for carbon dioxide of the synthesis gas production device (12) or the discharge line (40) for carbon dioxide of the separating device (38) and the discharge line (30) for carbon dioxide the separating device (28) are connected to a carbon dioxide compression device (42) which ei ne discharge line, which is connected to one of the at least one supply line (18) for carbon dioxide of the synthesis gas production facility (12), and/or e2) a flue gas return line connected to the discharge line (26) for flue gas of the synthesis gas production facility (12), the flue gas return line and the discharge line (30) for carbon dioxide of the separating device (28) is either connected directly to one of the at least one supply line (18) for carbon dioxide of the synthesis gas production device (12) or the flue gas return line and the discharge line (30) for carbon dioxide of the separating device (28) are connected to one Carbon dioxide compression device (42) are connected, which has a discharge line which is connected to one of the at least one supply line (18) for carbon dioxide of the synthesis gas production device (12), and wherein the plant (10) further comprises an electrolysis device (56) for separating water into hydrogen and oxygen, wherein the electrolyzer (56) has a water supply line (58), an oxygen discharge line (60) and a hydrogen discharge line (62), and wherein from the oxygen discharge line (60) a line (68) into the oxygen-containing gas supply line (24) to the synthesis gas production facility (12) leads. 2. Plant (10) according to claim 1, characterized in that the synthesis gas production device (12) also comprises a hydrogen supply line (63) which leads from the hydrogen discharge line (62) of the electrolysis device to the synthesis gas production device (12). 3. Plant (10) according to claim 1 or 2, characterized in that the synthesis gas production device (12) is a dry reformer which contains a nickel oxide catalyst and can be operated at a pressure of 10 to 50 bar and a temperature of 700 to 1,200°C. 4. Plant (10) according to at least one of the preceding claims, characterized in that the Fischer-Tropsch device (34) and/or the refining device (36) have a gas discharge line (50, 52) which is connected to the supply line (22) for fuel of the synthesis gas production facility (12) is / are connected. 5. Plant (10) according to at least one of the preceding claims, characterized in that the refining device (36) has one or more product discharge lines (48, 48′, 48″) for synthetic fuels has, wherein at least one of the one or more product discharge lines (48, 48', 48") for synthetic fuels is connected via a return line (54) to the supply line (22) for fuel of the synthesis gas production device (12), so that part of the in synthetic fuels produced by the refining facility (36) can be passed as fuel into the heat generation section of the syngas production facility (12). 6. Plant (10) according to claim 5, characterized in that it comprises a control device which controls the amount of synthetic fuel fed into the heat generation section of the synthesis gas production device (12) as fuel in such a way that the synthesis gas production device (12) and preferably the entire plant (10) no external fuel needs to be supplied. 7. Plant (10) according to at least one of the preceding claims, characterized in that from the hydrogen discharge line (62) of the electrolysis device (56) a line (64) to the Fischer-Tropsch device (34), from the hydrogen discharge line ( 62) a line (66) from the electrolysis device (56) to the refining device (36) and from the hydrogen discharge line (62) of the electrolysis device (56) a line (65) to the synthesis gas compression device (43). 8. Plant (10) according to at least one of the preceding claims, characterized in that it comprises a water desalination device (70) which has a fresh water supply line (72) and a discharge line (74) for desalinated water, the discharge line (74) for desalinated water Water is connected to the water supply line of the electrolysis device (56), the water desalination device (70) preferably having one or more anion and cation exchangers and a membrane device for degassing, which is designed in such a way that water can be desalinated and degassed to such an extent that its conductivity is less than 20 pS/cm, preferably less than 10 pS/cm, particularly preferably less than 5 pS/cm and most preferably a maximum of 2 pS /cm lies. 9. Plant (10) according to at least one of the preceding claims, characterized in that it comprises a water purification device (76) which has a water supply line (80) leading from the refining device (36) to the water purification device (76) and a water supply line (80) from the fishing Tropsch device (34), water supply line (78) leading to the water purification device (76) and water supply line (82) leading from the synthesis gas production device (12) to the water purification device (76), each for purification of water occurring therein and preferably also one from the carbon dioxide compression device (42) comprises the water supply line (81) leading to the water purification device (76), with the water purification device (76) preferably being connected to the water demineralisation device (70) via a line (88), so that water purified in the water purification device (76) is fed into the Water desalination device (70) passed who the can. 10. Plant (10) according to claim 9, characterized in that the water purification device (76) comprises an anaerobic reactor. 11. Plant (10) according to at least one of the preceding claims, characterized in that it has a methane steam reformer (31) as the second synthesis gas production device (31) for producing a hydrogen and carbon monoxide-comprising raw synthesis gas from methane, water and hydrogen, the methane -Steam reformer (31) a hydrogen supply line (61), a methane supply line (13), a Water (steam) supply line (23), a discharge line (21) for raw synthesis gas and a discharge line (85) for water, the hydrogen supply line (61) being connected to the hydrogen discharge line (62) of the electrolysis device (56), the discharge line (21) for raw synthesis gas is connected to the discharge line (20) for raw synthesis gas of the synthesis gas production device (12) and preferably the discharge line (85) for water is connected to the water purification device (76). 12. Plant (10) according to at least one of the preceding claims, characterized in that the separating device (28) is followed by a synthesis gas compression device (43) for compressing the gas to the pressure required in the Fischer-Tropsch synthesis, the synthesis gas compression device (43 ) is connected to the separating device (28) via a line (32) and to the Fischer-Tropsch device (34) via a synthesis gas feed line (44), the synthesis gas compression device (43) preferably having a hydrogen feed line (65) which is connected to the Electrolysis device (56) is connected. 13. Plant (10) according to at least one of the preceding claims, characterized in that it further comprises a methanation device (11) for converting carbon dioxide and hydrogen into methane and water, the methanation device (11) having a carbon dioxide supply line (19), a hydrogen supply line (67), which is connected to the hydrogen discharge line (62) of the electrolysis device (56), has a methane discharge line (17) and a water discharge line (87), the methane discharge line (17) being connected to the methane supply line (14) for the synthesis gas production device (12 ) is connected and preferably the water discharge line (85) of the methanation device (11) is connected to the water purification device (76). 14. A method for producing synthetic fuels, in particular jet turbine fuel (kerosene), naphtha and/or diesel, which is carried out in a plant (10) according to at least one of the preceding claims. 15. The method according to claim 14, characterized in that no carbon dioxide is discharged in the method. 16. The method according to claim 14 or 15, characterized in that gas produced in the Fischer-Tropsch facility (34), gas produced in the refining facility (36) and a portion of the synthetic fuels produced in the refining facility as fuel into the heat generation section of the synthesis gas production facility (12) are conducted, the process being controlled in such a way that no external fuel has to be supplied to the synthesis gas production device (12) and preferably to the entire plant (10). 17. The method according to at least one of claims 14 to 17, characterized in that part of the hydrogen generated in the electrolysis device (56) of the Fischer-Tropsch device (34), part of the hydrogen generated of the refining device (36) and part of the hydrogen produced in the electrolysis device (56) is fed to the synthesis gas production facility (12), the H2/CO molar ratio in the raw synthesis gas produced in the synthesis gas production facility (12) being controlled so that it is 1.15 to 1.80 and preferably 1 .15 to 1.50. 18. The method according to at least one of claims 14 to 17, characterized in that in the synthesis gas production device (12) a dry reforming is carried out, in which a nickel oxide catalyst is used, and the dry reforming is operated at a pressure of 10 to 50 bar and a temperature of 700 to 1,200°C. 19. The method according to at least one of claims 14 to 18, characterized in that a crude synthesis gas comprising carbon monoxide and hydrogen is produced from methane, water and hydrogen in a methane steam reformer (31), the methane steam reformer (31) receiving water (steam ), methane and hydrogen from the electrolysis device (56) are fed in and raw synthesis gas and water are removed from the methane steam reformer (31), the raw synthesis gas being fed to the separating device (28) and preferably the water being fed to the water purification device (76), wherein dry reforming is carried out in the synthesis gas production device (12), the ratio between the dry reformer and the methane steam reformer is adjusted to 30 to 60% to 40 to 65%, based on the methane input, in the raw synthesis gas produced in the dry reformer an H2/ CO ratio of 1.13 to 1.80 and preferably 1.15 to 1.50 is set and in which in the raw synthesis gas produced by the methane steam reformer is adjusted to a H2/CO ratio of 3.20 to 3.60. 20. The method according to at least one of claims 14 to 19, characterized in that carbon dioxide and hydrogen supplied from the electrolysis device (56) are also converted into methane and water in a methanation device (11), the methane being fed to the synthesis gas production device (12). and preferably the water is fed to the water purification device (76).