EP4288589A1

EP4288589A1 - Method and system for producing hydrocarbons

Info

Publication number: EP4288589A1
Application number: EP22718200.3A
Authority: EP
Inventors: Markus Kinzl
Original assignee: Siemens Energy Global GmbH and Co KG
Current assignee: Siemens Energy Global GmbH and Co KG
Priority date: 2021-04-30
Filing date: 2022-03-25
Publication date: 2023-12-13
Also published as: CL2023003195A1; US20240286975A1; WO2022228793A1; CA3218074A1; AU2022264724A1

Abstract

The invention relates to a method for producing hydrocarbons (6), having the steps of: a) carrying out an electrolysis (3) of water, whereby hydrogen and oxygen are produced; b) generating a carbon source which has carbon dioxide and/or carbon monoxide or substantially consists of carbon dioxide and/or carbon monoxide; c) producing (5) the hydrocarbons (6) from the hydrogen produced in step a) and the carbon dioxide produced in step b), wherein at least some of the produced hydrocarbons are provided in the form of liquid hydrocarbons and an exhaust gas is formed together with the hydrocarbons (6), said exhaust gas having hydrogen, carbon dioxide, and/or carbon monoxide; d) separating the exhaust gas from the liquid hydrocarbons (6); and e) recycling (8) exhaust gas in that a reaction of the exhaust gas with the oxygen and/or water produced in step a) is carried out, whereby recycled products are formed which have carbon dioxide and/or carbon monoxide, water, and optionally hydrogen. The method is particularly advantageous for producing hydrocarbons with methanol as a preferred product from a methanol synthesis (13). The methanol can be further used as a starting material (reactant) or intermediate product for producing (19) additional high-quality liquid hydrocarbons.

Description

description

Process and plant for the production of hydrocarbons

The invention relates to a method and a plant for the manufacture of hydrocarbons.

Regenerative hydrocarbons are distinguished by the fact that they are produced using regenerative starting materials. The regenerative starting materials can include, for example, regenerative carbon dioxide, which is obtained from biomass, for example, and regenerative hydrogen, which is obtained, for example, by electrolysis of water, in particular using electricity generated from renewable sources. The production of the regenerative educts and also the conversion of the regenerative educts into the regenerative hydrocarbons are energy-intensive and therefore also cost-intensive. Currently, the cost of producing regenerative hydrocarbons is several times higher than that of producing the same hydrocarbons from fossil raw materials.

So far, there have been various routes that enable the production of regenerative hydrocarbons. At this point, only the most important routes, which are the Fischer-Tropsch synthesis, the alcohol-to-fuel routes, the methanol route and the TIGAS process, will be briefly presented.

The Fischer-Tropsch synthesis enables the production of various synthetic hydrocarbon fuels, in particular diesel, kerosene, petrol and liquid gas. However, this technology has two disadvantages: The first disadvantage is that the products mentioned are produced side by side and only with low selectivity, which entails the need to have to market all the products mentioned at the same time. The desired production of a specific product with the simultaneous creation of only small amounts of the other products is practically impossible to achieve using this route. rich. The second disadvantage of the Fischer-Tropsch synthesis is that carbon monoxide is required as a starting material. Regeneratively obtained carbon dioxide must therefore first be reduced to carbon monoxide, which is only possible using the two immature technologies reverse water gas shift (RWGS) and solid oxide electrolysis (SOEC). The high temperatures in the range of more than 800 °C associated with RWGS and SOEC place extreme demands on the required materials and catalysts. In addition, under these conditions, relatively rapid coking of the active surfaces is to be expected.

The alcohol-to-fuel routes are based on the production of ethanol by synthesis gas fermentation, in which carbon dioxide and/or carbon monoxide and hydrogen are microbiologically converted into ethanol. The ethanol is then dehydrated to ethylene, which is oligomerized to oligomers. The oligomers are then hydrogenated to the hydrocarbons. In this way, various hydrocarbons can be produced with comparatively high selectivities, such as kerosene. In addition to the typically low space-time yield of synthesis gas fermentation, various aspects of the scale-up are viewed critically. This raises the question of whether alcohol-to-fuel routes can play a dominant role on a large industrial scale in the future.

The methanol route, based on the production of methanol from carbon dioxide and hydrogen (CO2 + 3 H2 ^ CH3OH +

H2O) and/or from carbon monoxide and hydrogen (CO +

2 H2 ^ CH3OH) and the further processing of the methanol to form hydrocarbons is more selective than the Fischer-Tropsch synthesis, but less selective than the alcohol-to-fuel routes. The scale-up possibilities are viewed positively and the direct usability of renewable carbon dioxide is another major advantage of this route. A disadvantage of the prior art is the need to separate from the measurement carried out with carbon dioxide water of reaction produced during the methanol synthesis by means of an energy-intensive distillation. The methanol dewatered in this way can then be converted into various end products. The methanol-to-kerosene technology is still in the development stage (pilot plant scale). Methanol-to-olefin technologies aimed at the production of ethylene, propylene and butylene have been partially developed to production scale. The best known is the methanol-to-gasoline technology, which has already been applied to the large-scale production of synthetic gasoline. In addition to the main product, petrol, liquid gas and, in small quantities, a Ci/C2 hydrocarbon mixture are produced.

FIG. 1 shows the process according to the prior art methanol route. A mass flow 78 which has carbon dioxide and/or carbon monoxide and hydrogen or consists of carbon dioxide and/or carbon monoxide and hydrogen is fed to a synthesis of methanol 13 . This creates a mass flow 71 which has methanol, water and unreacted starting materials. Even with very high turnovers of more than 90%, the losses are not accepted. Therefore, a separation 14 of the mass flow 71 is carried out, the water and the methanol being separated from the unreacted starting materials by a condensation in the separation 14 . The unreacted reactants form a mass flow 72 which is fed back to the synthesis of methanol 13 . The mixture of methanol and water formed in the separation 14 is fed in a mass flow 73 to a distillation 15 in order to separate the metha nol from the water. The water can be fed to a waste water treatment 17 in a mass flow 75 . The methanol must be fed in a mass flow 74 to a condensation 16 (condenser at the top of the distillation column) and in a subsequent mass flow 76 to an evaporation 18 since the subsequent hydrocarbon synthesis 19 takes place in the gas phase. A part of the resulting in the condensation 16 condensate 16 can as a mass flow 79 to the be returned to the top of the column. In the separation 14 a first cooling 81 has to take place, in the distillation 15 a first heating 82 has to take place, in the condensation 16 a second cooling 83 has to take place and in the evaporation 18 a second heating 84 has to take place. This makes the process energy-intensive and therefore cost-intensive. It is nevertheless necessary to return the unreacted reactants in the mass flow 72, which becomes understandable when the high energy consumption in the regenerative production of these reactants is taken into account.

An alternative technology to the methanol-to-gasoline technology is the TIGAS process, in which a mixture is produced in the first step that mainly contains methanol, dimethyl ether and water. This mixture is converted directly into gasoline without separating the water. Despite this simplification and various technological and economic advantages, the TIGAS technology is currently not suitable for the production of regenerative hydrocarbons because, similar to the Fischer-Tropsch synthesis, the TIGAS process uses carbon monoxide as a starting material (3 CO + 3 H ₂ -> CH3-O-CH3 + C0 ₂₎ so that the described problem of the low maturity of the RWGS technology and SOEC technology also comes into play here.

In order to be able to produce the liquid hydrocarbons inexpensively, it is necessary in all processes that the starting materials used are used as completely as possible and/or that as little energy as possible is used in the process.

The object of the invention is therefore to create a method and a plant with which liquid hydrocarbons can be produced inexpensively.

The method according to the invention for producing hydrocarbons comprises the steps of: a) performing electrolysis of water, whereby hydrogen and oxygen are produced; b) Generating a carbon source containing coal comprises or consists essentially of carbon dioxide or carbon monoxide; c) Production of the hydrocarbons from the hydrogen produced in step a) and the carbon source produced in step b), wherein at least some of the hydrocarbons produced are present as liquid hydrocarbons and, in addition to the hydrocarbons, an exhaust gas is formed which contains hydrogen, carbon dioxide and comprises carbon monoxide or consists essentially of hydrogen and carbon dioxide or hydrogen and carbon monoxide and optionally comprises gaseous hydrocarbons; wherein in step c) methanol is produced in a first process stage in an equilibrium reaction (13) and the methanol, the hydrogen not converted in the equilibrium reaction and the carbon source not converted in the equilibrium reaction are fed to a second process stage in which the hydrocarbons ( 6) are produced from the methanol; d) separating the exhaust gas from the liquid hydrocarbons; e) performing an exhaust gas utilization (8), in which a reaction of the exhaust gas with the oxygen produced in step a) or with the oxygen produced in step a) and water or only with water Runaway leads, whereby utilization products are formed, the water , Have carbon dioxide and carbon monoxide, or consist essentially of water and carbon dioxide or essentially of water and carbon monoxide, and wherein the utilization products optionally each have hydrogen.

Exhaust gas utilization advantageously produces heat, which can also be utilized, for example by converting the heat into electricity, for example by carrying out the reaction in step e) in a gas turbine, and/or by using the heat, for example to carry out evaporation and/or distillation. By converting or using the heat to electricity, the process for producing the hydrocarbons is advantageously inexpensive. Exhaust gas recycling can be carried out by combustion of the exhaust gas with the oxygen produced in step a), which is particularly rich in energy due to its purity, is carried out. This has the additional advantage that the oxygen generated in step a) in the electrolysis is also utilized, making the process even cheaper. Alternatively, the exhaust gas utilization can be carried out by gasifying the exhaust gas by reacting it with the water. The gasification can be carried out without the addition of oxygen or with the addition of the oxygen produced in step a) in the electrolysis. Here, too, the utilization of the oxygen in the gasification process makes the process particularly cost-effective. By carrying out the reaction in step e) using the oxygen produced in step a) and not using air, it is also advantageously achieved that essentially no undesirable substances such as nitrogen and/or noble gases are present entered into the procedure at this point.

In order to achieve that part of the hydrocarbons produced is present as the liquid hydrocarbons, the reaction products produced in step c) can be cooled. The resulting liquid hydrocarbons can be marketed particularly well.

In step c), it is provided that in a first process stage, methanol is produced in an equilibrium reaction and the methanol and the hydrogen that has not reacted in the equilibrium reaction and the carbon source that has not reacted in the equilibrium reaction are fed to a second process stage, in which the hydrocarbons are produced from the methanol. In comparison to the process according to the prior art (see FIG. 1), the unreacted hydrogen and the unreacted carbon source are not recycled to the synthesis of methanol (see mass flow 72). This eliminates the energy-intensive separation of the methanol, which Process is particularly inexpensive. This is made possible by the fact that the unreacted hydrogen and the unreacted carbon source are converted to the recycling products in step e) after the second process stage in the waste gas recycling. With the design as a two-stage procedure in step c), a particularly efficient methanol synthesis is made possible with the inventions.

In step e) when carrying out an exhaust gas evaluation (8), various combinations of the reactants are advantageously and flexibly possible, which are brought together for a reaction with the exhaust gas. In this way it is possible to bring the exhaust gas together with the oxygen produced in step a). Furthermore, it is possible to bring the exhaust gas together with the oxygen generated in step a) and with water, in particular fresh water, for an exhaust gas utilization reaction. Finally, it is possible that the reaction of the exhaust gas is carried out only with water. As an alternative or in addition to the oxygen produced, water, in particular fresh water, is reacted with the exhaust gas.

In any case, utilization products are thereby formed which have water, carbon dioxide and carbon monoxide, or consist essentially of water and carbon dioxide or essentially of water and carbon monoxide, and the utilization products optionally each have hydrogen.

Different reaction paths are therefore possible on the product side.

It is particularly preferred that the equilibrium reaction of the first stage of the process produces water which is not separated from the methanol, the hydrogen which has not reacted in the equilibrium reaction and the carbon source which has not reacted in the equilibrium reaction. This also makes the method particularly cost-effective. That water formed in the equilibrium reaction of the first stage of the process can be removed in a step g). The hydrocarbons preferably contain saturated hydrocarbons and/or olefins or preferably consist of saturated hydrocarbons and/or olefins.

The liquid hydrocarbons, in particular the saturated hydrocarbons, can be, for example, gasoline, kerosene, diesel and/or liquid gas.

The specific reaction conditions in step c) for producing the hydrocarbons depend, for example, on which hydrocarbons are produced. For example, in the production of gasoline, the pressure can be from 20 bar to 30 bar, the temperature can be from 200°C to 400°C, in particular from 250°C to 400°C, and a heterogeneous catalyst can be present, such as for example a zeolite catalyst, in particular a ZSM-5 catalyst.

It is preferred that the process has the step: f) separating water from the utilization products. As a result, the recycling products essentially consist of carbon dioxide, carbon monoxide and/or hydrogen. As a result, the recycling products have a higher value than if the water were still contained in the recycling products.

The water separated off in step f) is preferably used in step a) for the electrolysis in order to produce hydrogen and oxygen therefrom, and/or used in step e) to carry out the reaction with the exhaust gas.

In contrast to fresh water, the water separated off in step f) is already demineralized. Therefore, the amount of fresh water to be fed to the process and to be demineralized beforehand can be reduced, making the process even more cost-effective. In addition, the method is also suitable for being carried out in regions in which only few fresh water resources are available. It is preferred that in step c) the hydrocarbons are also produced from the utilization products generated in step e). Advantageously, this means that little or no carbon is lost from the process, making the process even more cost-effective. It is particularly preferred here to separate off the water in step f), because the production of the hydrocarbons is an equilibrium reaction and water contained in the recycling products would reduce the yield of the liquid hydrocarbons in step c).

Heat generated in step e) is preferably fed partially or completely to an endothermic step or to a plurality of endothermic steps of the process. This can reduce the cost of performing the method. The endothermic step or steps can be, for example, evaporation and/or distillation.

It is preferred that the process is carried out continuously. This results in particular in a continuous mass flow of the liquid hydrocarbons, a continuous mass flow of the exhaust gas and a continuous mass flow of the utilization products.

It is preferred that in step c) some of the hydrocarbons produced are present as gaseous hydrocarbons and in step e) the reaction is also carried out with at least some of the gaseous hydrocarbons produced in step c). As a result, advantageously more heat is produced in step e) than if the reaction is only carried out with the carbon dioxide and/or the carbon monoxide and the hydrogen. This is particularly relevant when not enough heat is released in step e) to maintain endothermic processes of the process. It is particularly preferred that the reaction is gasification. It is preferred that in step c) the part of the gaseous hydrocarbons is formed as part of the exhaust gas and/or the part of the gaseous hydrocarbons is separated from the liquid hydrocarbons by distillation and then mixed with the exhaust gas.

The gaseous hydrocarbons particularly preferably contain Ci hydrocarbon, C ₂ hydrocarbon, C 3 hydrocarbon and/or C ₄ hydrocarbon or consist particularly preferably essentially of Ci hydrocarbon, C ₂ hydrocarbon, C ₃ hydrocarbon and/or C ₄ hydrocarbon. These hydrocarbons usually have a lower commercial value than the hydrocarbons that have longer chains. The Ci carbon and the C ₂ carbon may be contained in the exhaust gas. It is conceivable that the C 1 -hydrocarbon, the C ₂ -hydrocarbon, the C ₃ -hydrocarbon and/or the C ₄ -hydrocarbon are at least partially dissolved in the liquid hydrocarbons. It is conceivable that the C 1 -hydrocarbon and the C ₂ -hydrocarbon are separated off in a first distillation column and are then at least partially mixed with the exhaust gas. It is also conceivable that the C3 hydrocarbon and the C4 _hydrocarbon are separated off in a second distillation column and are then at least partially mixed with the exhaust gas.

Water is also formed in step c) and the process preferably comprises the step: g) separating the water from the exhaust gas and the hydrocarbons. This can be done, for example, by condensing the water and separating the phases from the liquid hydrocarbons. Since it is particularly preferred that the water separated off in step g) is used in step a) for the electrolysis in order to generate hydrogen and oxygen therefrom, and/or is used in step e) to react with to be carried out on the exhaust gas. In contrast to fresh water, the water separated off in step g) is already demineralized. ted. Therefore, the amount of fresh water to be fed to the process and to be demineralized beforehand can be reduced, making the process even more cost-effective. In addition, the method is also suitable for being carried out in regions in which there are only few fresh water resources. If the water separated off in step g) is used in step e) to carry out the reaction with the exhaust gas, there is the additional advantage that any hydrocarbons dissolved in the water are also gasified.

In step b), carbon dioxide is preferably extracted from air, biomass is burned, biomass is gasified and/or combustion exhaust gases are generated. Methods for extracting the carbon dioxide from the air are known by the term "direct air capture" (DAC). For example, the carbon dioxide is extracted from the air by means of adsorption or by a reaction with sodium hydroxide or potassium hydroxide before it is usually removed by feeding is desorbed again from energy and is thus made available for subsequent processes. By extracting the carbon dioxide from the air or from the biomass, the hydrocarbons can advantageously be obtained regeneratively, i.e. without the use of fossil carbon sources. Alternatively, it is conceivable If the carbon dioxide is extracted from the air, this has the advantage that essentially no undesirable substances such as nitrogen and/or noble gases enter the process.

It is preferred that the biomass is burned or gasified using the oxygen generated in step a). This advantageously ensures that essentially no unwanted substances, such as nitrogen and/or noble gases, get into the process. The system according to the invention is set up to carry out the method according to the invention or a preferred embodiment thereof.

The invention is explained in more detail below with reference to the attached schematic drawings. Show it

FIG. 1 shows a flow chart of a conventional method,

FIG. 2 shows a flow chart of the method according to the invention,

FIG. 3 shows a flow chart of a preferred embodiment of the method according to the invention.

As can be seen from Figure 2, a process for producing hydrocarbons comprises the steps of: a) performing electrolysis 3 of water, whereby hydrogen and oxygen are produced; b) generating a carbon source 4 comprising carbon dioxide and/or carbon monoxide or consisting essentially of carbon dioxide and/or carbon monoxide; c) Production 5 of the hydrocarbons from the hydrogen produced in step a) and the carbon source produced in step b), with at least part of the hydrocarbons produced being present as liquid hydrocarbons 6 and, in addition to the hydrocarbons 6, an exhaust gas also being formed which hydrogen, carbon dioxide and/or carbon monoxide; d) separating the exhaust gas from the liquid hydrocarbons 6; e) performing an exhaust gas utilization 8 in which a reaction of the exhaust gas with the oxygen generated in step a) and/or with water is carried out, whereby utilization products are formed which have carbon dioxide and/or carbon monoxide, water and optionally hydrogen.

Exhaust gas utilization can be carried out, for example, by incinerating the exhaust gas with the oxygen produced in step a). In another For example, the exhaust gas utilization can be performed by performing gasification of the exhaust gas through a reaction with the water. The gasification can be carried out without the addition of oxygen or with the addition of the oxygen produced in step a) in the electrolysis.

FIG. 2 shows that fresh water 1 can be supplied to electrolysis 3 in a mass flow 51 . The hydrogen produced in step a) can be fed in a mass flow 53 to a reactor in which the hydrocarbons 6 are produced in step c). The oxygen generated in step a) can be conducted in a mass flow 55 that is separate from the mass flow 53, so that the hydrogen and the oxygen cannot be mixed.

In order to provide the carbon source in step b), a carbonaceous starting material 2 can be provided in a mass flow 52 . The carbon source can be generated from the mass flow 52 and can be fed to the reactor in a mass flow 54 . For example, carbon dioxide can be extracted from air in step b), so that the carbonaceous starting material 2 is the air. In step b), biomass can be burned and/or gasified, as a result of which the carbon-containing starting material 2 is the biomass. If the biomass is burned, mainly carbon dioxide will be produced, if the biomass is gasified, mainly carbon monoxide will be produced. It is conceivable that the biomass is burned or gasified using the oxygen generated in step a). This has the advantage that no nitrogen or noble gases get into the process. For this purpose, the oxygen generated in step a) can be provided partially or completely in a mass flow 70 which is conducted separately from the mass flow 53, so that the oxygen cannot mix with the hydrogen. In another example, combustion exhaust gases can be generated, in particular by gasification and/or combustion of fossil fuels as the carbonaceous feedstock. The hydrocarbons can be produced in step c) at a temperature in the reactor of at least 200° C., in particular from 250° C. to 400° C. The pressure may be from 20 bar to 30 bar and a heterogeneous catalyst may be present, such as a zeolite catalyst, especially a ZSM-5 catalyst.

The exhaust gas separated off in step d) can be provided in a mass flow 58 and

- hydrogen,

- carbon dioxide and/or carbon monoxide,

- Optionally gaseous hydrocarbons, in particular Ci-hydrocarbon, C2-hydrocarbon, C3-hydrocarbon and / or C4-hydrocarbon, have or essentially

- hydrogen,

- carbon dioxide and/or carbon monoxide,

- Optional gaseous hydrocarbons, in particular Ci hydrocarbon, C2 hydrocarbon, C3 hydrocarbon and / or C4 hydrocarbon exist. In the event that water is also formed in step c), the method can have the following step: g) separating the water 7 from the exhaust gas and the liquid hydrocarbons 6. This results in a substantially pure mass flow 56 of the liquid Hydrocarbons 6. The water 7 can be separated from the exhaust gas by a condensation and a phase separation of the water 7 . The water 7 separated off in step g) can form a mass flow 57 and is used, for example, at least partially in step a) for the electrolysis 3 in order to produce the hydrogen and the oxygen therefrom. Alternatively, it is conceivable that the water 7 is cleaned and drained in a sewage treatment plant.

In the event that in step e) the combustion or the gasification with the oxygen generated in step a) is carried out, the mass flow 55 can be combined with the mass flow 58 be mixed to perform the exhaust gas utilization 8. In the event that the gasification is carried out in step e), the water 7 separated in step g) can be used at least partially in step e) to carry out the reaction with the exhaust gas, compare the mass flows 67 and 65. Alternatively or In addition, the gasification in step e) can be carried out using another fresh water 11, compare the mass flows 66 and 65.

In step e) when carrying out an exhaust gas evaluation 8, different combinations of the starting materials are advantageously and flexibly possible, which are brought together for a reaction with the exhaust gas. It is thus possible to combine the exhaust gas with the oxygen generated in step a). Furthermore, it is possible to combine the exhaust gas with the oxygen produced in step a) and with water, in particular fresh water, for an exhaust gas utilization reaction. Finally, it is possible that the reaction of the exhaust gas is carried out only with water. As an alternative or in addition to the oxygen produced, water, in particular with additional fresh water 11, is reacted with the exhaust gas.

Different reaction paths are therefore possible on the product side.

After step e), a mass flow 59 is produced which has carbon dioxide, carbon monoxide, hydrogen and/or water and/or consists essentially of carbon dioxide, carbon monoxide, hydrogen and/or water. If the combustion is carried out in step e), the in the Carbon contained in the exhaust gas is essentially converted to carbon dioxide. If the gasification is carried out in step e), the proportion of carbon monoxide in the mass flow 59 will be higher than the proportion of carbon dioxide. FIG. 2 also shows that the method can have the following step: f) separating 9 water 12 from the recycling products. The water 12 can be separated by condensing the water 12 . This creates a mass flow 63 which is formed by the water 12 separated off in step f). The water 12 separated in step f) can be used in step a) for the electrolysis 3 (compare mass flow 69) in order to generate the hydrogen and oxygen from it, and/or in step e) used to react with the perform exhaust gas. The portion of the mass flow 63 that is not used in the mass flow 69 can form a mass flow 64 . As an alternative to using the water 12 separated off in step f), the water 12 can also be cleaned and discharged in a sewage treatment plant.

FIG. 2 shows that in step c) the hydrocarbons can also be produced from the utilization products produced in step e). For this purpose, downstream of the separation 9 of the water 12, a mass flow 60, which has carbon dioxide, carbon monoxide and/or hydrogen or essentially consists of carbon dioxide, carbon monoxide and/or hydrogen, is fed in the direction of the reactor. Optionally, part of the mass flow 60 can be discharged in a mass flow 61 as a residual waste gas 10 in order to discharge any by-products that may occur and thus to prevent their accumulation in the process. A mass flow 62, which is optionally formed by the mass flow 60 minus the mass flow 61, is then fed to the reactor.

The process can be carried out continuously. This means, for example, that the mass flows 53, 54 and 58 in particular are continuous. Heat generated in step e) is preferably supplied partially or completely to an endothermic step or to a plurality of endothermic steps of the process, such as evaporation and/or distillation.

It is also conceivable that in step c) some of the hydrocarbons produced are present as gaseous hydrocarbons and in step e) the reaction is also carried out with at least some of the gaseous hydrocarbons 6 produced in step c). In step c), the part of the gaseous hydrocarbons can be formed as a part of the exhaust gas (this would mean that in Figure 2 already at the beginning of the mass flow 58 this has the part of the gaseous hydrocarbons) and/or the part of the gaseous hydrocarbons can be separated from the liquid hydrocarbons 6 as a mass flow 68 by distillation and then added to the exhaust gas, i.e. added to the mass flow 58. The gaseous hydrocarbons can contain Ci hydrocarbon, C2 hydrocarbon, C3 hydrocarbon and/or C4 hydrocarbon or consist essentially of Ci hydrocarbon, C2 hydrocarbon, C3 hydrocarbon and/or C4 hydrocarbon. The C 1 hydrocarbon and the C 2 hydrocarbon are preferably present at the beginning of the mass flow 58 and the C 3 hydrocarbon and the C 4 hydrocarbon are preferably present in the mass flow 68 and are added to the mass flow 58 after the beginning thereof.

As can be seen from FIG. 3, methanol can be produced in step c) in a first process stage in an equilibrium reaction and the methanol, the hydrogen not reacted in the equilibrium reaction and the carbon source not reacted in the equilibrium reaction can be fed to a second process stage , in which the hydrocarbons are produced from the methanol.

In order to produce the methanol 13, a mass flow 78 can be provided which has hydrogen and carbon has monoxide and/or carbon dioxide or consists essentially of hydrogen and consists of carbon monoxide and/or carbon dioxide. In the first stage of the process, the reaction conditions can include, for example: a temperature of 200° C. to 300° C., a pressure of at least 50 bar, in particular of 50 bar to 250 bar, and a metal oxide catalyst can be present.

The fact that the methanol is produced 13 results in a mass flow 71 which has methanol and hydrogen, as well as carbon monoxide and/or carbon dioxide and optionally water. The mass flow 71 is supplied without separating one of the aforementioned substances from a preparation 19 of hydrocarbons with methanol as the reactant, d. H. supplied to the second stage of the process. For example, in the second stage of the process, the pressure can be from 20 bar to 30 bar, the temperature can be from 200° C. to 400° C., in particular from 250° C. to 400° C., and a heterogeneous catalyst can be present, such as, for example a zeolite catalyst, especially a ZSM-5 catalyst. Steps d) and e) are carried out in the same way as in FIG. The exhaust gas can also have C 1 to C 4 hydrocarbons.

It is conceivable that in the equilibrium reaction of the first process stage, water is formed (if the methanol is produced with carbon dioxide as the starting material), which is fed to the second process stage. The water is only separated off in step d).

The process is operated particularly advantageously for the production of hydrocarbons with methanol as the preferred product from a methanol synthesis 13 . The methanol can in turn be reused as a valuable starting material (starting material) or as an intermediate product for the production (19) of other high-quality liquid hydrocarbons.

In the event that the hydrocarbons are Ci-hydrocarbon, C2-hydrocarbon, C3-hydrocarbon and/or C4- Have hydrocarbons, the C 1 -hydrocarbon, the C 2 -hydrocarbon, the C 3 -hydrocarbon and/or the C 4 -hydrocarbon can, for example, be recycled particularly easily if the process is carried out at a location where there is also a refinery. The C 1 hydrocarbon, the C 2 hydrocarbon, the C 3 hydrocarbon and/or the C 4 hydrocarbon can be used as starting material in the refinery. In the case of the refinery, for example, it can be a steam cracker. Ethylene can be produced in the steam cracker, which has a high commercial value.

The heat generated in step e) can also be marketed if the process is carried out at a location where other plants of the chemical or pharmaceutical industry are also located. The heat generated in step e) can be used, for example, to carry out an endothermic process, such as evaporation or distillation, in the other plants.

A system is set up to carry out the method.

Claims

patent claims

A method for producing hydrocarbons (6), comprising the steps of: a) performing electrolysis (3) of water, thereby producing hydrogen and oxygen; b) generating a carbon source (4) comprising carbon dioxide and carbon monoxide or consisting essentially of carbon dioxide or carbon monoxide; c) Production (5) of the hydrocarbons (6) from the hydrogen produced in step a) and the carbon source produced in step b), wherein at least some of the hydrocarbons produced are present as liquid hydrocarbons and, in addition to the hydrocarbons (6), also a Waste gas is formed which has hydrogen, carbon dioxide and carbon monoxide or consists essentially of hydrogen, carbon dioxide or hydrogen and carbon monoxide, wherein in step c) methanol is produced in a first process stage in an equilibrium reaction (13) and the methanol which in hydrogen which has not been converted to the equilibrium reaction and the carbon source which has not been converted in the equilibrium reaction are fed to a second process stage in which the hydrocarbons (6) are produced from the methanol; d) separating the exhaust gas from the liquid hydrocarbons fen (6); e) carrying out a waste gas utilization (8), in which a reaction of the waste gas is carried out with the oxygen produced in step a) or with the oxygen produced in step a) and water or with water, whereby utilization products are formed which contain water, Have carbon dioxide and carbon monoxide, or consist essentially of water and carbon dioxide or essentially of water and carbon monoxide, and wherein the utilization products optionally each have hydrogen.

2. The method according to claim 1, wherein in step c) in the equilibrium reaction water is formed, which is fed to the second stage of the process.

3. The method according to claim 1 or 2, with the step: f) separating (9) water (12) from the recycling products th.

4. The method according to claim 3, wherein the water (12) separated off in step f) is used in step a) for the electrolysis (3) in order to produce the hydrogen and the oxygen therefrom, and/or used in step e). is used to carry out the reaction with the exhaust gas.

5. The method according to any one of claims 1 to 4, wherein in step c) the hydrocarbons (6) are also produced from the utilization products generated in step e).

6. The method according to any one of claims 1 to 5, wherein the process is carried out continuously.

7. The method according to any one of claims 1 to 6, wherein in step c) a portion of the hydrocarbons produced is present as gaseous hydrocarbons and in step e) the reaction is also carried out with at least a portion of the gaseous hydrocarbons produced in step c).

8. The method according to claim 7, wherein in step c) the part of the gaseous hydrocarbons is formed as part of the exhaust gas and/or the part of the gaseous hydrocarbons is separated by distillation from the liquid hydrocarbons (6) and then added to the exhaust gas is mixed.

9. The method according to claim 7 or 8, wherein the part has Ci hydrocarbon, C2 hydrocarbon, C3 hydrocarbon and/or C4 hydrocarbon or consists essentially of Ci hydrocarbon, C2 hydrocarbon, C3 hydrocarbon and/or C4 hydrocarbon exists.

10. The method according to any one of claims 1 to 9, wherein in step c) water is also formed and the method comprises the step: g) separating the water (7) from the exhaust gas and the hydrocarbons (6).

11. The method according to claim 10, wherein the water (7) separated off in step g) is used in step a) for the electrolysis (3) in order to produce the hydrogen and the oxygen therefrom, and/or used in step e). is used to carry out the reaction with the exhaust gas.

12. The method according to any one of claims 1 to 11, wherein in step b) carbon dioxide is extracted from air, biomass is burned, biomass is gasified and/or combustion exhaust gases are generated.

13. The method according to claim 12, wherein the biomass is burned or gasified by means of the oxygen generated in step a).

14. Plant that is set up to carry out a method according to any one of claims 1 to 13.