Production of chemical products with reduced or negative carbon dioxide footprint from carbon dioxide

Abstract

A carbon dioxide negative emission process for preparing a polymer product, comprising the following steps: a) capturing carbon dioxide (1, 11.1, 11.2) from a gas comprising carbon dioxide, in particular from air or exhaust gas; b) converting (2, 12.1) at least a portion of the captured carbon dioxide to an intermediate product comprising olefins; c) optionally subjecting the olefins of the intermediate product to a derivatization reaction (3, 13.1, 13.2) to obtain an olefin derivative; d) further subjecting the olefins and / or olefin derivatives, in particular with at least one further monomer, to a polymerization reaction (4, 14.1, 14.2) in order to obtain a polymer product; wherein the energy required to carry out one or more process steps is provided in the form of renewable energy at least for step a), in particular at least for steps a) and b), in particular for all steps a) to d).

Description

Technical Field

[0001] The present invention relates to a process for producing polymer products, in particular a process with negative carbon dioxide emissions, and also to an apparatus for carrying out the corresponding process, in particular a chemical plant. Background Art

[0002] As the world continues to face the challenge of climate change, there is growing awareness of the importance of reducing carbon emissions across all economic sectors. To address this challenge, many companies are working to develop CO2-neutral chemical products that emit no net carbon dioxide into the atmosphere during their production, use, and disposal.

[0003] CO2-neutral chemicals are those produced using low-carbon or renewable energy and emit no net CO2 over their lifecycle. This means that the carbon emissions associated with their production and use are offset by removing an equivalent amount of CO2 from the atmosphere through activities such as carbon capture and storage or the use of renewable energy.

[0004] Examples of CO₂-neutral chemical products include bioplastics, which are made from renewable resources such as corn starch or sugar cane and can replace traditional petroleum-based plastics. Other examples include biofuels, which are made from renewable resources such as algae or waste vegetable oils and can be used as a replacement for fossil fuels in transportation and other applications.

[0005] For example, polyethylene terephthalate (PET) is currently produced primarily from the petroleum-derived components terephthalic acid and ethylene glycol. Replacing terephthalic acid with furandicarboxylic acid is known to be advantageous because one component can be produced from renewable raw materials. The other component, monoethylene glycol (MEG), can be produced from bioethanol. However, using 100% renewable raw materials and renewable energy can achieve climate neutrality at best.

[0006] Therefore, attempts have been made to produce so-called CO2-negative products. These are products or technologies that actively remove more CO2 from the atmosphere than is emitted during their production, use, and disposal. This means they have a net negative carbon footprint and can therefore help mitigate the effects of climate change.

[0007] In this regard, for example, approaches involving carbon negative emission fuel production include US

[0008] A method described in 2010 / 0311157A teaches the production of biofuels from algae as a feedstock. The method is said to be carbon negative due to the high CO2 absorption of algae.

[0009] While developing negative CO2 emissions products is an important step in reducing carbon emissions and mitigating the effects of climate change, there are several challenges associated with their creation. One of the main challenges is that implementing these technologies can be very expensive and can require significant investment in research and development.

[0010] Another challenge is scaling these technologies, as many currently known CO2-negative products are still in the early stages of development and may not be viable for large-scale production. Furthermore, the energy and resource requirements to produce CO2-negative products may offset their carbon-negative benefits, especially if they are not powered by renewable energy.

[0011] Therefore, there is still a need for improved solutions that at least partially overcome the above-mentioned disadvantages. Summary of the Invention

[0012] The object of the present invention is therefore to create an improved process for preparing chemical products, in particular polymer products, with the lowest possible carbon footprint. In particular, the process should be able to produce CO2-negative chemical products in a cost-effective, scalable and / or efficient manner.

[0013] Specifically, the core of the present invention is a process for preparing polymer products, especially a process for negative carbon dioxide emissions, comprising the following steps:

[0014] a) capturing carbon dioxide from gases comprising carbon dioxide, in particular from air or exhaust gases, in particular by direct air capture;

[0015] b) converting at least a portion of the captured carbon dioxide into intermediate products comprising or consisting of olefins, in particular ethylene and / or propylene; preferably, by:

[0016] (i) electrochemical reduction of carbon dioxide in the presence of water; and / or

[0017] (ii) hydrogenation of carbon dioxide with hydrogen to form methanol and subsequent conversion of the methanol to olefins, preferably by:

[0018] Methanol to olefins (MTO); and / or

[0019] ●Methanol to gasoline reaction (MTG);

[0020] c) optionally, subjecting the olefins of the intermediate product to a derivatization reaction to obtain olefin derivatives, such as diols and / or acrylonitrile;

[0021] d) further polymerizing the olefin and / or olefin derivative, in particular with at least one other monomer, to obtain a polymer product;

[0022] Therein, preferably, at least for step a), in particular at least for steps a) and b), and especially for all steps a) to d), the energy required for carrying out the process steps is provided in the form of renewable energy.

[0023] Most preferably, the process of the present invention is a negative carbon dioxide emission process. This means, in particular, that when the process is carried out and thereby during the production of the polymer product, the process removes more carbon dioxide from the environment (e.g., the atmosphere) than is emitted during the production of the polymer product.

[0024] In principle, however, the process can also be carried out in a non-CO2-negative manner, for example in a CO2-neutral manner, or in a manner such that more CO2 is emitted during the production of the polymer product than is removed from the environment, in particular the atmosphere, by the process.

[0025] The process of the present invention provides an efficient, inexpensive, sustainable and robust process for producing polymer products with a low or even negative carbon footprint. Thanks to the combination of process steps of the present invention, the process can be implemented without any fossil raw materials and fossil energy.

[0026] Furthermore, the process of the present invention is highly modular. This means that the individual process steps can be carried out in one and the same location or plant, or they can be carried out in different locations. For example, steps a) and b) can be carried out in an area with high solar radiation. The olefins produced in this manner can then be transported to other locations where existing facilities for carrying out further process steps are available.

[0027] The process of the invention can be carried out particularly advantageously in the Sun Belt, along the equator, between the Tropic of Cancer and the Tropic of Capricorn, and / or in deserts. In these locations, there is virtually unlimited solar energy available, i.e., solar radiation that can be harnessed using photovoltaic cells and / or solar thermal energy that can be harvested using solar thermal collectors.

[0028] Particularly preferably, the energy required for carrying out the process steps is in particular electrical and / or thermal energy. The required electrical energy is in particular generated by photovoltaic cells and / or wind power units, and / or the required thermal energy is in particular generated by solar thermal collectors. However, other forms of energy can also be used.

[0029] Therefore, in a further preferred embodiment, the process according to the invention comprises the further process step of generating renewable energy, in particular using photovoltaic units and / or wind power units and / or solar thermal collectors.

[0030] In particular, the required energy is generated at the same location, in particular in the same plant, where step a), in particular steps a) and b) or all steps are carried out.

[0031] The carbon dioxide captured in step a) is at least partially used to produce polymer products and / or other chemicals. In addition, if desired, a portion of the captured carbon dioxide can be further converted into solid carbon.

[0032] In particular, in step a), carbon dioxide is captured using a process known as "direct air capture" (DAC).

[0033] Direct air capture (DAC) is a technology that uses specialized machinery to remove carbon dioxide directly from ambient air. DAC technology typically involves passing air through filters and / or solutions that selectively capture CO2. The CO2 is then separated and stored and / or used in other processes.

[0034] In the context of the present invention, direct air capture proves to be particularly beneficial since it is cost-effective and CO2 can be captured directly from a point source such as a power plant or an industrial facility where step b) or further process steps are carried out.

[0035] Particularly preferably, the capture of carbon dioxide in step a) is effected using chemical absorbents or adsorbents, in particular alkaline substances, such as alkali metal or alkaline earth metal hydroxides in solid or liquid form.

[0036] Advantageously, in process step a), in a first stage, the gas comprising carbon dioxide is brought into contact with sodium hydroxide, in particular sodium hydroxide solution and / or solid sodium hydroxide, in order to absorb the carbon dioxide and form sodium carbonate.

[0037] In particular, the combination with carbon dioxide from ambient air and / or from waste gas streams with slightly higher carbon dioxide concentrations can be established by using low-cost sodium hydroxide, such as concentrated aqueous caustic soda that is readily available on the market and / or can be obtained in situ from seawater using desalination facilities and electrolysis processes.

[0038] In the context of the present invention, "caustic soda solution" or "caustic soda" refers to an aqueous sodium hydroxide solution. In particular, the caustic soda solution is a concentrated caustic soda solution, a saturated caustic soda solution or a supersaturated caustic soda solution.

[0039] A caustic soda solution with a sodium hydroxide concentration of at least 10 mol / L is also called a concentrated caustic soda solution. At room temperature, a saturated caustic soda solution has a sodium hydroxide concentration of approximately 32 mol / L, and a caustic soda solution with a higher concentration is called a supersaturated caustic soda solution. The saturation concentration varies at different temperatures.

[0040] For example, for the first stage in step a), the aqueous caustic soda solution or the sodium hydroxide solution has a sodium hydroxide concentration of 1-32 mol / L, in particular 10-19 mol / L, respectively.

[0041] In the second stage of step a), gaseous carbon dioxide and sodium hydroxide, in particular sodium hydroxide solution, can subsequently be formed from the sodium carbonate obtained in the first stage and / or the sodium bicarbonate converted from the sodium carbonate obtained in the first stage. Therefore, the second stage is carried out in particular at a temperature below 350° C., preferably below 250° C., for example between 50° C. and 200° C., more preferably between 90° C. and 200° C.

[0042] The process of the present invention may require the consumption of large amounts of energy at low temperatures in step a). Heat below 350°C can be obtained virtually in unlimited quantities from solar thermal energy, is CO₂ neutral, and is inexpensive. In this embodiment, the decomposition of sodium carbonate is carried out at low temperatures (below 350°C), preferably using heat from solar thermal energy and / or waste heat. However, other energy sources may also be used, such as heat generated by photovoltaic, wind, and / or other energy conversion.

[0043] In particular, the second phase of step a) is carried out according to one of the following procedures I, II and / or III:

[0044] I. the sodium carbonate obtained in the first stage is provided in a solid state and is at least partially thermally decomposed, thereby releasing gaseous carbon dioxide, and the sodium hydroxide obtained by the thermal decomposition is extracted, in particular in parallel with the thermal decomposition of the sodium carbonate, preferably by means of an extractant;

[0045] II. The sodium carbonate obtained in the first stage is provided as an aqueous solution and is at least partially thermally decomposed by heating the aqueous solution, in particular to a temperature below the boiling point of the aqueous solution, so that gaseous carbon dioxide is released from the solution.

[0046] III. The sodium carbonate obtained in the first stage is provided as an aqueous solution and is at least partially separated into sodium bicarbonate and sodium hydroxide by means of an ion-selective membrane device, wherein in a third stage, the sodium bicarbonate obtained is at least partially thermally decomposed into carbon dioxide and sodium carbonate.

[0047] In particular, in the process according to the invention, no calcium compounds, in particular no calcium hydroxide, are used in step a).

[0048] It is further preferred in the process according to the invention that no potassium compounds, in particular no potassium hydroxide, are used in step a).

[0049] Furthermore, preferably, no microporous hollow fiber membranes are used in step a).

[0050] In particular, the sodium carbonate obtained in the first stage of step a) can be temporarily stored, for example for at least one minute, at least one hour, at least one day, at least one week or at least one month, and then used in the second stage. Thus, sodium carbonate can be stored, for example, in solid form and / or in the form of an aqueous solution.

[0051] In particular, the first stage is carried out in such a way that water losses, in particular water losses to the atmosphere, are substantially avoided. This can be achieved in particular by a sufficiently high amount or proportion of sodium hydroxide.

[0052] In a first preferred embodiment, in a first stage, a gas comprising carbon dioxide is brought into contact with solid sodium hydroxide particles, in particular powdered sodium hydroxide.

[0053] Therefore, in particular, a gas containing carbon dioxide and moisture, in particular residual moisture, is used. This gas is usually provided, for example, when using air or exhaust gas as the carbon dioxide-containing gas in the first stage. This allows the in-situ production of an aqueous caustic soda solution that can react with the carbon dioxide in an efficient manner. Furthermore, under these conditions, no additional water is required.

[0054] However, if desired, the carbon dioxide-comprising gas can also be brought into contact with the solid sodium hydroxide particles, in particular pulverulent sodium hydroxide, in the presence of additional water vapor, in particular by humidifying the carbon dioxide-comprising gas.

[0055] In particular, solid sodium hydroxide particles are brought into contact with a gas containing moisture, in particular residual moisture, in particular to form an aqueous caustic soda solution, in particular a concentrated aqueous caustic soda solution, and during and / or after the formation of the aqueous caustic soda solution, the caustic soda obtained is brought into contact with a gas containing carbon dioxide in order to produce sodium carbonate. The gas containing moisture can be, for example, a gas containing carbon dioxide and / or another gas containing moisture that is brought into contact with the sodium hydroxide.

[0056] According to another very advantageous embodiment, in the first stage, the gas containing carbon dioxide is brought into contact with a sodium hydroxide solution, in particular an aqueous caustic soda solution, to form sodium carbonate. In particular, the aqueous caustic soda solution is a concentrated, saturated or supersaturated aqueous caustic soda solution.

[0057] In particular, the sodium hydroxide concentration of the caustic soda solution is 1-32 mol / L, in particular 10-19 mol / L. This is another possibility for obtaining sodium carbonate in an efficient manner. Therefore, the commercially available, low-cost caustic soda solution can be used directly without further treatment.

[0058] In the second stage of step a), gaseous carbon dioxide and a sodium hydroxide solution, in particular an aqueous solution of sodium hydroxide, are formed from the sodium carbonate obtained in the first stage and / or from the sodium bicarbonate converted from the sodium carbonate obtained in the first stage at a temperature of less than 350° C., preferably less than 250° C., more preferably between 90° C. and 200° C.

[0059] Preferably, the sodium hydroxide, in particular the sodium hydroxide solution, obtained in the second stage is returned to the first stage of step a) and reused in the first stage of step a). Preferably, the sodium hydroxide solution is concentrated before being returned. However, the sodium hydroxide can also be used for other purposes.

[0060] Very preferably, the thermal energy required in the second stage is provided in the form of heat from solar thermal collectors, solar thermal power plants and / or waste heat.

[0061] Therefore, in particular, the process of the present invention further comprises the step of obtaining heat from solar energy of solar collectors, solar thermal power plants and / or waste heat, and providing this heat in the second stage of step a) for the hot composition of sodium carbonate and / or sodium bicarbonate converted from the sodium carbonate obtained in the first stage.

[0062] In the second stage of process I, solid sodium carbonate is provided, for example by precipitation of sodium carbonate from caustic soda in the first stage, and the sodium carbonate is thermally decomposed to release gaseous carbon dioxide. Preferably, the sodium carbonate to be decomposed is in the form of a granular material, for example a powdered material.

[0063] In Procedure I, sodium hydroxide (NaOH) produced during the thermal decomposition of sodium carbonate (Na2CO3) is extracted. This extraction further drives the decomposition process, making complete decomposition possible.

[0064] In a preferred embodiment of Procedure I, water is used as the extractant, wherein preferably, sodium carbonate is at least partially precipitated, while sodium hydroxide remains in solution. In another preferred embodiment, an aqueous solution of a water-soluble alcohol is used as the extractant, the water-soluble alcohol being preferably a water-soluble primary alcohol, more preferably methanol, ethanol, n-propanol, n-butanol or a mixture thereof, and preferably, sodium carbonate is at least partially precipitated, while sodium hydroxide remains in solution.

[0065] In particular, during and / or after the extraction, the extractant with the sodium hydroxide dissolved therein is subjected to a separation process, in particular a distillation, in order to recover the sodium hydroxide and the extractant.

[0066] In summary, in the second stage procedure I for producing sodium hydroxide solution from sodium carbonate and releasing carbon dioxide, the release of carbon dioxide from solid sodium carbonate is preferably achieved by direct thermal decomposition, wherein the final product sodium hydroxide solution is preferably removed by extraction to enable further decomposition.

[0067] In procedure II of the second stage of step a), the sodium carbonate obtained in the first stage of step a) is provided as an aqueous solution and is at least partially thermally decomposed by heating the aqueous solution, in particular to a temperature below the boiling point of the aqueous solution, so that gaseous carbon dioxide is released from the solution, in particular by evaporation.

[0068] In particular, the decomposition of sodium carbonate is carried out by heating or boiling an aqueous solution of sodium carbonate to a temperature near the boiling point of the solution, preferably under normal pressure.

[0069] Although not required, the formation of water vapor bubbles at the bottom of a bottom-heated reaction vessel can significantly aid in the removal of carbon dioxide from solution.

[0070] Many small bubbles with a large surface area and a long residence time of the bubbles in the solution improve the emission. The water vapor is condensed again at the top of the vessel, preferably with heat recovery, and pure carbon dioxide is released. Pure carbon dioxide (wet) is preferably extracted from the gas phase and can then be dried and further processed.

[0071] According to a first preferred option, the solution obtained during the thermal decomposition process is diluted with water to promote the decomposition of the sodium carbonate. This provides a suitably diluted sodium carbonate solution during the heating and / or boiling process. Furthermore, a more concentrated sodium carbonate solution can be used and continuously diluted during the heating and / or boiling process. This prevents the release of carbon dioxide from ceasing.

[0072] For both variants, the conversion percentage can be controlled by final dilution.The diluted solution comprises mainly caustic soda and sodium carbonate residues and is suitable for direct reuse in the first stage of step a) after concentration, for example by distillation or reverse osmosis.

[0073] According to a second preferred option, an acidic ion exchange resin, in particular a weakly acidic ion exchange resin, is added to the solution to reduce the sodium ion concentration and thereby promote the decomposition of sodium carbonate. Therefore, in order to reduce the sodium ion concentration, a weakly acidic ion exchange resin is preferably used.

[0074] According to a third preferred option, an amphoteric metal compound, in particular an amphoteric metal oxide and / or an amphoteric metal hydroxide, is added to the solution in order to reduce the sodium ion concentration and thereby promote the decomposition of the sodium carbonate.

[0075] Amphoteric metal oxides and hydroxides are insoluble in water but can dissolve in sodium hydroxide solution. In doing so, they bind dissolved sodium ions, lowering the pH and promoting the formation of sodium carbonate. Amphoteric compounds dissolved in sodium hydroxide solution can be precipitated and hydrolyzed in a simple and energy-efficient manner to achieve a cyclic process, in contrast to protonic acids that form sodium salts as reaction products.

[0076] Many amphoteric compounds are known. Particularly preferred are aluminum hydroxide, zinc hydroxide, and / or silicon dioxide. These substances are preferred, inter alia, because they are readily available and non-toxic. However, other amphoteric compounds may also be used. Preferably, however, the amphoteric metal compound used is one or more of aluminum hydroxide, zinc hydroxide, and silicon dioxide.

[0077] Preferably, the metal hydroxide is aluminum hydroxide Al(OH)3 and / or zinc hydroxide Zn(OH)2. Hydroxides formed directly from the oxides in sodium carbonate solution can also be used. The amphoteric metal hydroxides combine with sodium ions from the solution to form sodium hydroxymetalates, for example, sodium tetrahydroxyaluminate Na[Al(OH)4] and sodium tetrahydroxyzincate Na2[Zn(OH)4].

[0078] In summary, a process for recovering carbon dioxide from a gas containing carbon dioxide, in particular from air or exhaust gases, by absorbing CO 2 in a sodium hydroxide solution and releasing CO 2 from the sodium carbonate formed is disclosed, when procedure II is followed in the second stage of step a), wherein in particular:

[0079] - using concentrated sodium hydroxide solution in the first stage of step a), so that sodium carbonate precipitates during the absorption process due to exceeding its solubility in concentrated sodium hydroxide solution,

[0080] Alternatively, use dilute sodium hydroxide solution and concentrate the solution until sodium carbonate precipitates.

[0081] The sodium carbonate obtained in the first stage of step a) is dissolved in water and at least partially thermally decomposed by heating and / or boiling in the second stage of step a) with the release of carbon dioxide.

[0082] - Optionally, the remaining solution is concentrated and returned to the first stage of step a).

[0083] In another aspect of the present invention, when following the procedure III of the second stage of step a), an absorption process for capturing carbon dioxide from a gas containing carbon dioxide, in particular from air or exhaust gases, is proposed for recovering the carbon dioxide by absorption in a sodium hydroxide solution followed by an electrochemically driven disproportionation reaction and thermal decomposition.

[0084] In particular, when following procedure III of the second stage, the sodium carbonate obtained in the first stage is converted into sodium bicarbonate and caustic soda by a disproportionation reaction in an electrochemical device.

[0085] In particular, the sodium carbonate obtained in the first stage is at least partially separated into sodium bicarbonate and sodium hydroxide by an ion-selective membrane, wherein the sodium bicarbonate obtained in the third stage is at least partially thermally decomposed into carbon dioxide and sodium carbonate. Therefore, in particular, the sodium carbonate used in the second stage is provided in the form of an aqueous solution.

[0086] The caustic soda or sodium hydroxide obtained in the second stage can be fed back to the first stage, while the electrochemically produced sodium bicarbonate can be thermally decomposed into sodium carbonate, carbon dioxide and water at temperatures up to 200° C. The resulting sodium carbonate produced in the third stage can again undergo an electrochemically driven disproportionation reaction.

[0087] In particular, in this method, the electrochemical treatment is carried out only on sodium carbonate to produce sodium bicarbonate and sodium hydroxide by disproportionation. The sodium bicarbonate obtained in this way is then heated in a known manner at low temperatures, for example at a temperature of 50° C. to 200° C., preferably using solar heat or waste heat.

[0088] In particular, the ion-selective membrane device is a membrane capacitive device, wherein preferably at least the cathode chamber, the intermediate chamber and the anode chamber are separated from one another by a cation-selective membrane.

[0089] Specifically, the membrane capacitive device includes a cathode chamber, an intermediate chamber, and an anode chamber, each separated from the other by a cation-selective membrane, wherein the intermediate chamber is filled with a first-stage sodium carbonate aqueous solution, and the cathode chamber and the anode chamber are supplied with a slurry of water and conductive particles (especially carbon particles). During operation, a voltage is applied through the electrodes so that the conductive particles in the cathode chamber have a negative charge to adsorb sodium ions in the intermediate chamber, and the carbon particles in the anode chamber have a positive charge to adsorb hydroxide ions, wherein the process is controlled so that sodium bicarbonate is mainly formed in the intermediate chamber.

[0090] The voltage is preferably adjusted in such a way that no gas is generated at the electrodes in order to avoid undesirable side reactions of the water electrolysis. The charge on the surface of the conductive particles (especially carbon particles) in the cathode chamber is at least partially neutralized by the sodium ions that migrate from the intermediate chamber via the cation-selective membrane (capacitive charging).

[0091] Preferably, the slurry of conductive particles loaded with sodium ions coming from the cathode chamber is mixed with the slurry of conductive particles loaded with hydroxide ions outside the device.

[0092] This produces a sodium hydroxide solution which is preferably reused in the first stage after settling of the conductive particles.

[0093] In another embodiment, the ion-selective membrane device is an electrodialysis device, in particular an electrodialysis device comprising only cation-selective membranes.

[0094] In particular, electrodialysis can be used to deplete sodium ions. In an electrodialysis unit, water electrolysis preferably takes place at the edge electrodes, whereby hydrogen and oxygen are produced, in contrast to capacitive membrane enrichment, where preferably no water electrolysis takes place at the electrodes.

[0095] In particular, the electrodialysis unit comprises several cation-selective membranes interposed between an anode and a cathode, each membrane separating adjacent compartments alternately loaded with water and sodium carbonate, such that compartments in which sodium hydroxide is formed alternate with compartments in which sodium bicarbonate is formed.

[0096] The anode chamber and the cathode chamber (the edge chamber with the electrodes) are preferably filled with an electrolyte, such as a sodium sulfate solution, to ensure good conductivity for electrolysis. To counteract the loss of sodium ions in the anode chamber and the accumulation of sodium ions in the cathode chamber, the anolyte and catholyte are preferably continuously pumped and mixed.

[0097] Preference is given here to using exclusively cation-selective membranes, which prevent the migration of carbonate ions towards the anode, in contrast to conventional electrodialysis, in which cation-selective membranes alternate with anion-selective membranes.

[0098] The solid sodium bicarbonate obtained with procedure III can be stored temporarily, used directly as a product, or used as a starting product, for example, for the electrochemical reduction of carbonates. When free carbon dioxide is required, a third stage can be carried out.

[0099] In the third stage, the sodium bicarbonate produced in the second stage is decomposed in a known manner at a temperature below 350° C., preferably below 250° C., for example between 50° C. and 200° C., more preferably between 90° C. and 200° C., with release of carbon dioxide. The sodium carbonate produced in the third stage can be dissolved again and reused in the second step.

[0100] In summary, a process for recovering carbon dioxide from a gas containing carbon dioxide, in particular from air or exhaust gases, by absorbing CO 2 in sodium hydroxide and releasing CO 2 from the sodium bicarbonate formed, when following procedure III in step a), is disclosed, wherein in particular:

[0101] - contacting a sodium hydroxide solution as absorbent with a gas comprising carbon dioxide, thereby forming sodium carbonate, which is preferably obtained due to its solubility product

[0102] Too large to precipitate, and preferably recovered as a solid by sedimentation, filtration or centrifugation;

[0103] and preferably, the sodium carbonate obtained is fed to an electrochemical device in which a consumption of up to preferably 50% by weight of sodium ions occurs in an electric field through an ion-selective membrane. This separates the sodium bicarbonate from the sodium hydroxide, both originating from the disproportionation reaction of the sodium carbonate;

[0104] - and preferably, returning the sodium hydroxide obtained in the electrochemical device to step a)

[0105] The concentration of the sodium hydroxide solution can be increased before circulation;

[0106] - and preferably, the dried sodium bicarbonate is used directly as a product or is subjected to thermal decomposition,

[0107] wherein high concentrations of carbon dioxide are released as a product of the process;

[0108] - and preferably, the sodium carbonate produced by the thermal decomposition is returned to the electrochemical device for use in the production of sodium hydroxide and sodium bicarbonate by disproportionation reaction.

[0109] In step b), at least a portion of the captured carbon dioxide is converted into an intermediate product comprising olefins.

[0110] Optionally, the intermediate product thus obtained can be subjected to a separation step to separate the olefins and / or other substances, such as by-products, contained in the intermediate product obtained. Suitable separation processes, such as (fractional) distillation, filtration, membrane separation processes, precipitation, chromatography, extraction, stripping, vapor-liquid separation, etc., are known per se to those skilled in the art.

[0111] In a preferred embodiment, step b) is carried out according to option (i) by electrochemical reduction of carbon dioxide in the presence of water to obtain a mixture comprising ethylene.

[0112] In particular, the electrochemical reduction is carried out using renewable energy, in particular using electrical energy generated by photovoltaic units and / or wind power units.

[0113] In particular, the mixture comprising ethylene further comprises at least one compound selected from oxygen, formic acid, formate, carbon monoxide, hydrogen, methane and / or lower alcohols. In particular, the formate is sodium formate. In the electrochemical reduction process of carbon dioxide, these by-products are generally produced. When using special reaction conditions, the proportion of by-products can be reduced. However, for the process of the present invention, this is not a requirement for allowing the electrochemical reduction to be operated in an efficient manner.

[0114] The climate-active methane produced as a by-product can be further converted into carbon (C) by recycling hydrogen (H2) to produce carbon that can be stored for a long time. This allows the entire process to produce not only CO2-neutral ethylene components but also CO2-overcompensated production.

[0115] Therefore, in a further preferred embodiment, the methane contained in the mixture comprising ethylene is decomposed into carbon and hydrogen.

[0116] Likewise, formic acid and / or formates are preferably decomposed into carbon monoxide and hydrogen, in particular by thermolysis.

[0117] Particularly preferably, hydrogen and carbon monoxide are reacted to give methanol, the carbon monoxide originating directly from a mixture comprising ethylene and / or from the decomposition of formic acid and / or formate, and / or wherein the hydrogen originates directly from a mixture comprising ethylene and / or from the decomposition of methane.

[0118] In particular, the reaction of hydrogen and carbon monoxide is carried out using a catalyst, in particular a Cu-based catalyst, in particular a Cu / ZnO / Al2O3 catalyst.

[0119] Thus, formic acid, formate, hydrogen and carbon monoxide can be converted into CO₂-negative methanol. The methanol thus obtained can be used as a feedstock and / or it can be converted into olefins, as described, for example, in step b)(ii). In this way, all the ethylene in the mixture comprising ethylene as well as all by-products can be recycled, converted into less problematic substances and / or used for further applications.

[0120] These reactions and the conditions required for carrying out the above reactions are known per se to those skilled in the art.

[0121] According to a further preferred embodiment, step b) is carried out according to option (ii). In particular, the hydrogenation of carbon dioxide and the subsequent conversion to olefins are carried out using renewable energy, in particular using energy produced by photovoltaic units, wind power units and / or solar thermal collectors.

[0122] Therefore, preferably, carbon dioxide is subjected to a catalytic hydrogenation reaction, wherein preferably, a Cu-based catalyst and / or an In2O3-based catalyst, in particular Cu / ZnO / Al2O3, is used. In particular, the reaction temperature is selected from 150-350°C and / or the pressure during the reaction is 0.1-10 MPa.

[0123] In particular, step b) is carried out according to option (ii) and the methanol obtained is converted into olefins, in particular ethylene and / or propylene, using a zeolite catalyst, in particular a silicoaluminophosphate zeolite catalyst, in a methanol to olefins reaction (MTO). A particularly preferred reaction temperature is in the range of 250-550°C.

[0124] The methanol-to-olefins reaction is a petrochemical process. This process and suitable reaction conditions are known in petrochemicals. Thus, in particular, a mixture of ethylene and propylene is formed from methanol via the intermediate dimethyl ether over a silicoaluminophosphate zeolite catalyst. The ratio of propylene (C3) to ethylene (C2) olefins can be varied by selecting the process conditions, for example from 0.77 in the ethylene mode to 1.33 in the propylene mode.

[0125] In another preferred embodiment, step b) is carried out according to option (ii) and the methanol obtained is converted into olefins, in particular ethylene and / or propylene, in a methanol to gasoline reaction (MTG) using an aluminosilicate catalyst, such as ZSM-5.

[0126] If step b) is carried out according to option (ii), steam cracking can be carried out, optionally after the methanol to gasoline (MTG) reaction. Thus, in particular, steam cracking is carried out using a silicoaluminophosphate molecular sieve catalyst.

[0127] The methanol-to-gasoline reaction is a petrochemical process. Such processes and suitable reaction conditions are well known in petrochemicals. The methanol-to-gasoline reaction is also known as the Mobil process. Typically, the reaction temperature is about 400°C.

[0128] Steam cracking is a petrochemical process in which saturated hydrocarbons are broken down into smaller, usually unsaturated hydrocarbons. Steam cracking is a robust method for producing olefins such as ethylene and / or propylene.

[0129] In particular, optional step c) is carried out. Thus, preferably, olefin derivatives are produced from the olefins of the intermediate products, in particular from ethylene and / or propylene. Derivatives are, for example, vinyl chloride, vinyl acetate, styrene, ethylene oxide, propylene oxide, monoethylene glycol, propylene glycol, acrylic acid, acrylic esters and / or acrylonitrile.

[0130] Derivatization is a technique used in chemistry to convert a compound into a product with a similar chemical structure (a reactive derivative), called a derivative. Typically, specific functional groups of the compound to be derivatized participate in the derivatization reaction, converting the compound into a derivative with different reactivity, solubility, boiling point, melting point, aggregation state, and / or chemical composition.

[0131] Derivatization reactions for obtaining the above derivatives are known to those skilled in the art. Derivatization reactions include, for example, oxidation, halogenation, hydrohalogenation, alkylation, and ammoxidation reactions.

[0132] In optional step c), it is particularly preferred to react the ethylene obtained in step b) with oxygen to produce ethylene oxide. The ethylene oxide thus obtained can then be reacted, in particular hydrolyzed, to produce monoethylene glycol (MEG). The MEG thus obtained can be CO₂-negative. In particular, MEG can be used as a feedstock for the production of other chemical products.

[0133] In another preferred embodiment, in step c), the propene obtained in step b) is subjected to an ammoxidation reaction to form a nitrile, in particular acrylonitrile. The nitrile thus obtained can also be CO2-negative.

[0134] The process according to the invention thus makes it possible to obtain widely used chemical raw materials, such as olefins, in particular ethylene and / or propylene, and also methanol and glycols, from carbon dioxide.

[0135] According to a very preferred embodiment, in step d), the obtained diol (especially monoethylene glycol) is polymerized with terephthalic acid or 2,5-furandicarboxylic acid to obtain polyethylene terephthalate (PET) or polyethylene furandicarboxylate (PEF) as the polymer product. Suitable polymerization initiators, chain transfer agents and polymerization conditions are known to those skilled in the art.

[0136] 2,5-Furandicarboxylic acid is therefore obtained in particular from biomass, preferably from fructose, in particular via the intermediate compound 5-hydroxymethylfurfural.

[0137] Likewise, the substances and / or monomers used in the process according to the invention, in particular in step c) and / or step d), are preferably at least partially bio-based, in particular completely bio-based substances and / or monomers.

[0138] Compounds from biomass have measurable 14 C isotope ratio. 14 C content, it is possible to clearly determine whether a compound such as 2,5-furandicarboxylic acid is biobased and in what proportion. Therefore, biobased compounds are distinguished from non-biobased compounds by 14Compounds produced from fossil feedstocks are not biobased and do not have a measurable ratio of carbon isotopes. 14 C content of raw materials 14 Carbon content and biobased content can be determined according to ASTM D6866 “Standard Test Method for Biobased Content of Solid, Liquid, and Gaseous Samples by Radiocarbon Analysis”.

[0139] When appropriate conditions are selected, the raw materials in steps a) to c) remove more CO₂ from the atmosphere during production than is released during combustion of the polymer product at the end of its life. This fact, in turn, applies to the polymer product (e.g., PET or PEF) and the consumer goods made from it, such as bottles. Thus, these polymer products can be produced with negative CO₂ emissions.

[0140] In another preferred embodiment, in step d), the olefins and / or diols are converted into polyethylene glycol (PEG), polypropylene (PP), and / or polyethylene (PE). Suitable polymerization initiators, chain transfer agents, and polymerization conditions are known to those skilled in the art. As described above for PEG and PEF, these polymer products can also be produced with negative CO2 emissions.

[0141] In another preferred embodiment, acrylonitrile is produced in step c), in particular by the Sohio process, and then in step d), the acrylonitrile is polymerized to form polyacrylonitrile. Likewise, the polymer can also be produced with negative CO2 emissions.

[0142] In another preferred embodiment, polyacrylonitrile is subjected to a pyrolysis reaction to form carbon fibers. In particular, the carbon fibers can be used in conjunction with other materials, such as polymer products obtained using the process of the present invention, to form composite materials or carbon fiber reinforced polymers.

[0143] Carbon fibers are widely used in applications in the aerospace industry, the automotive industry, and / or civil engineering. Being able to produce carbon fibers, composite materials, or carbon fiber reinforced polymers with negative CO₂ emissions would be highly beneficial, as it would reduce the carbon footprint of products containing the carbon fibers.

[0144] In particular, carbon fibers, in particular in the form of composite materials or carbon fiber reinforced polymers, can be mixed with processable building materials, in particular processable mortar or concrete materials, to produce building elements for buildings and / or infrastructure, for example foundations, supports, beams, walls, floors and / or ceilings.

[0145] The processable building material comprises in particular a binder, aggregate and water. The binder may be selected from cement and / or other binder materials, such as geopolymers.

[0146] In particular, processable building materials contain a geopolymer binder, in particular as the sole binder. Such building materials are particularly advantageous with regard to CO₂ balance. Furthermore, since the relatively low pH of such binders can pose problems with the use of metal reinforcements, the use of carbon fibers as reinforcement elements is particularly advantageous. The combination of a geopolymer binder with carbon fibers produced according to the process of the present invention is particularly advantageous with regard to CO₂ balance.

[0147] In a further preferred embodiment, the process of the invention additionally comprises a step of providing hydrogen and / or oxygen by hydrolysis of water. In particular, the hydrogen and / or oxygen thus obtained are subsequently used in step b) (ii) and / or step c).

[0148] In particular, the hydrolysis is carried out using renewable energy, in particular using electrical energy generated by photovoltaic units and / or wind power units.

[0149] Another aspect of the present invention relates to a construction element obtainable by the process described above. In particular, the construction element is, for example, a foundation, support, beam, wall, floor and / or ceiling of a building or infrastructure.

[0150] Another aspect relates to an apparatus, in particular a chemical plant, in particular an apparatus for carrying out the above process, comprising:

[0151] a) a capture unit, in particular an adsorption unit, configured for capturing carbon dioxide from a gas comprising carbon dioxide, in particular from air or exhaust gas, in particular by direct air capture;

[0152] b) a conversion unit configured for converting at least a portion of the carbon dioxide captured by the capture unit into an intermediate product comprising olefins, in particular ethylene and / or propylene; wherein the conversion unit preferably comprises:

[0153] - a reduction unit for the electrochemical reduction of carbon dioxide in the presence of water; and / or

[0154] a hydrogenation unit for the hydrogenation of carbon dioxide with hydrogen to form methanol and the subsequent conversion of the methanol into olefins;

[0155] c) optionally, a derivatization unit configured for derivatizing at least a portion of the olefins in the intermediate product into olefin derivatives;

[0156] d) Polymerization units for polymerizing olefins and / or olefin derivatives, in particular with at least one further monomer, to obtain polymer products.

[0157] In another preferred embodiment, the device further comprises at least one unit selected from the group consisting of

[0158] a decomposition unit in which formic acid and / or formates are decomposed into carbon monoxide and hydrogen,

[0159] - a decomposition unit, in which methane is decomposed into carbon and hydrogen, and

[0160] - a synthesis unit in which hydrogen and carbon monoxide are converted into methanol;

[0161] - a hydrolysis unit for producing hydrogen and / or oxygen from water.

[0162] Optionally, the apparatus further comprises a carbonization unit for producing carbon (C) from the captured carbon dioxide and hydrogen.

[0163] In particular, the carbonization can be carried out by means of the Bosch reaction, which is carried out in particular in two steps with quantitative removal of water, preferably in the presence of an iron, cobalt and / or nickel catalyst.

[0164] Furthermore, the plant preferably comprises an energy unit configured to generate renewable energy, in particular a photovoltaic unit, a wind power unit and / or a solar thermal unit, to generate the energy required for carrying out the process steps. In particular, the energy unit provides energy in the form of electricity and / or heat.

[0165] In particular, the plant is configured for capturing at least 200,000 tons of CO2 per year, preferably at least 500,000 tons of CO2 per year.

[0166] According to a very preferred embodiment, the device is part of a factory, in particular a chemical plant. However, the individual units of the device can be located at different locations. In this case, the chemical plant is a distributed chemical plant.

[0167] Another aspect of the invention relates to a combined power plant and chemical plant for reducing the carbon dioxide content in the atmosphere, in particular for reducing the carbon dioxide content in the atmosphere and reducing the proportion of carbon dioxide in water, preferably seawater, and for the production of polymer products.

[0168] In particular, combined power stations and chemical plants include:

[0169] - at least one electrolysis unit for producing oxygen, which is connected to at least one electrolysis unit for receiving a certain amount of water (M H2O ) of the water supply line and is suitable for converting the absorbed water (M H2O ) is electrolyzed into a portion of oxygen (M O2 ) and a partial amount of hydrogen component;

[0170] at least one conversion unit, in particular a conversion unit as described above, configured for converting at least a portion of the carbon dioxide captured by the carbon dioxide adsorption unit into intermediate products comprising olefins, in particular ethylene and / or propylene; wherein

[0171] The conversion unit preferably comprises:

[0172] - a reduction unit for the electrochemical reduction of carbon dioxide in the presence of water; and / or

[0173] a hydrogenation unit for the hydrogenation of carbon dioxide with hydrogen to form methanol and the subsequent conversion of the methanol into olefins;

[0174] - optionally, at least one derivatization unit for derivatizing at least a portion of the olefins of the intermediate product into olefin derivatives;

[0175] at least one polymerization unit for polymerizing olefins and / or olefin derivatives, in particular with at least one other monomer, to obtain a polymer product;

[0176] at least one hydrogen delivery device connecting the electrolysis unit to the carbonization unit for carbon synthesis and, preferably, also for connecting the electrolysis unit to the conversion unit,

[0177] In particular, a hydrogenation unit connected to a conversion unit;

[0178] at least one carbon dioxide adsorption unit, in particular as described above, configured for purifying ambient air of the external atmosphere surrounding the unit, at least one air inlet for supplying ambient air and ambient air, and at least one downstream adsorbent device adapted to extract a quantity of carbon dioxide from the ambient air, in particular as described above; and

[0179] at least one carbon dioxide delivery device connecting the carbon dioxide adsorption unit with the carbonization unit and the conversion unit,

[0180] wherein the electrolysis unit has at least one component for discharging oxygen (M O2 ), and the carbon dioxide adsorption unit has at least one air outlet for discharging purified ambient air, wherein the oxygen outlet and the air outlet are open to the external atmosphere, and the carbonization unit has a carbon outlet for removing carbon to remove carbon,

[0181] as well as

[0182] In this case, at least one power generation unit is provided for the self-sufficient power supply of the factory, which power generation unit has one or more, in particular dedicated, renewable energy sources for generating electricity.

[0183] In particular, the further features of the plant can be realized according to DE 10 2021 104 746 B3, the content of which is incorporated herein by reference.

[0184] For the above plant, the various units are configured for carrying out the process of the invention. Thus, in particular, the carbon dioxide adsorption unit and the adsorbent unit are connected to a solar thermal heat source and / or a waste heat source.

[0185] Further advantageous embodiments and combinations of features emerge from the following detailed description and the entire content of the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0186] The accompanying drawings, used to illustrate the embodiments, show:

[0187] Figure 1 A flow chart of the process of the present invention for producing a polymer product;

[0188] Figure 2 Show Figure 1 a flow chart illustrating an embodiment of the first step 1 of a process in which carbon dioxide is captured directly from a gas containing carbon dioxide using sodium hydroxide;

[0189] Figure 3 exist Figure 2 Schematic diagram of the membrane capacitive process for the disproportionation reaction of sodium carbonate in the process shown;

[0190] Figure 4 The process for producing polyethylene terephthalate and polyethylene furandicarboxylate is shown. Figure 1 A flow chart of an embodiment of a process;

[0191] Figure 5 Show Figure 4 Flow chart of a further embodiment of a process of , wherein in addition to polyethylene terephthalate and polyethylene furandicarboxylate, further intermediate products are used;

[0192] Figure 6 Flowchart showing the production of carbon fibers or carbon fiber reinforced polymers.

[0193] In the figures, the same components have the same reference numerals. DETAILED DESCRIPTION

[0194] Figure 1A flow chart of the process of the present invention for producing a polymer product is shown. Specifically, in capture unit 1 (implementing step a) of the present invention), carbon dioxide is captured from a gas containing carbon dioxide, in particular from air or exhaust gas. The carbon dioxide thus obtained is then passed through conversion units 2(i) and / or 2(ii) (implementing step b) of the present invention). In unit 2(i), at least a portion of the captured carbon dioxide is electrochemically reduced in the presence of water to obtain an intermediate product containing olefins, in particular ethylene and / or propylene. In unit 2(ii), the carbon dioxide is first hydrogenated with hydrogen to form methanol. Subsequently, the methanol is subjected to a methanol-to-olefins reaction MTO and / or a methanol-to-gasoline reaction MTG to obtain an intermediate product containing olefins, in particular ethylene and / or propylene.

[0195] In the optional derivatization unit 3 (optional step c) of the present invention), olefins can be subjected to a derivatization reaction to obtain olefin derivatives, such as diols and / or acrylonitrile. According to the derivatization reaction, reactants such as oxygen, water and / or ammonia are provided.

[0196] Subsequently, the olefin and / or olefin derivative, if desired with at least one further monomer, is subjected to a polymerization unit 4 to obtain the polymer product (carrying out step d) of the present invention).

[0197] The hydrogen used in unit 2(ii) and also the oxygen suitable for use in the derivatization unit 3 can be prepared from water in the optional hydrolysis unit 1a.

[0198] Figure 2 Shown in Figure 1 A flow diagram of the process is shown in unit 1 of the process wherein carbon dioxide is captured directly from a gas containing carbon dioxide using sodium hydroxide.

[0199] In a first step 11.1, a gas containing carbon dioxide (CO2) is brought into contact with sodium hydroxide (NaOH), for example, a sodium hydroxide solution and / or solid sodium hydroxide, to absorb the carbon dioxide. During step 11.1, sodium carbonate (Na2CO3) is formed. Depending on the embodiment of step 11.2, the sodium carbonate is provided in solid form (procedure I) or in the form of an aqueous solution (procedures II and III).

[0200] In the second step 11.2, gaseous carbon dioxide and a dilute sodium hydroxide solution, in particular a sodium hydroxide solution, are formed from the sodium carbonate obtained in the first step a) and / or the sodium bicarbonate converted from the sodium carbonate obtained in the first step a) at a temperature below 350° C., preferably below 250° C., for example between 50° C. and 200° C., more preferably between 90° C. and 200° C. Step 11.2 can thus be carried out according to at least one of procedures I, II and / or III.

[0201] In procedure I, the sodium carbonate obtained in step 11.1 is used in solid form and is at least partially thermally decomposed, for example, at a temperature between 90° C. and 200° C., thereby releasing gaseous carbon dioxide. The additional sodium hydroxide obtained by thermal decomposition is extracted by means of an extractant, for example water or an aqueous alcohol solution, in particular in parallel with the thermal decomposition of the sodium carbonate.

[0202] In procedure II, the sodium carbonate obtained in step 11.1 is used in the form of an aqueous solution which is at least partially thermally decomposed by heating the aqueous solution, in particular to a temperature below the boiling point of the aqueous solution, thereby releasing gaseous carbon dioxide from the solution.

[0203] In procedure III, the sodium carbonate obtained in step 11.1 is used in the form of an aqueous solution and is at least partially separated into sodium bicarbonate and sodium hydroxide by means of an ion-selective membrane device, wherein the sodium bicarbonate obtained in the third step is at least partially thermally decomposed into carbon dioxide and sodium carbonate. Figure 3 , an exemplary embodiment of an ion-selective membrane device is shown.

[0204] Figure 3 A schematic diagram of a membrane capacitive device and process for the disproportionation reaction of sodium carbonate that can be used in procedure III is shown. Here, a concentrated sodium carbonate solution (Na2CO3 aqueous solution) is introduced into a central chamber D from one end and pumped in a countercurrent manner to a slurry of conductive activated carbon particles flowing through a cathode chamber B and an anode chamber F. The central chamber D is defined by two cation selective membranes C and E. Sodium ions migrate into the cathode chamber B through membrane C, while protons from the anode chamber F migrate into the central chamber D through membrane E. The outside of the cathode chamber B is defined by an edge electrode A made of a conductive material (such as carbon or stainless steel), which is conductively connected to the negative pole of a current source (not shown). The outside of the anode chamber F is defined by an edge electrode G, which is conductively connected to the positive pole of an external current source. The slurry of conductive activated carbon is pumped in a countercurrent manner through the anode chamber F and the cathode chamber B to the central chamber D.

[0205] In the cathode chamber B, the charge of the activated carbon particles applied by the edge electrodes A is neutralized by sodium ions migrating from the central chamber D via the cation-selective membrane C. In the anode chamber F, the positive charge of the activated carbon particles applied by the edge electrodes G is balanced by hydroxide ions from the dissociation of water. The protons released in this process migrate in the electric field through the cation-selective membrane e into the intermediate chamber D.

[0206] After passing through cathode chamber B or anode chamber F, the carbon slurries from both chambers merge outside the chambers, where they form sodium hydroxide in a neutralization reaction after the electric field is removed. The carbon particles are discharged during this process. The discharged carbon particles I are separated from the caustic soda H by filtration or sedimentation, slurried with fresh water, and returned to chambers B and F. The caustic soda H is added to the absorption unit in step 11.1 of the process.

[0207] Figure 4 The process for producing polyethylene terephthalate and polyethylene furandicarboxylate is shown. Figure 1 Flowchart of an implementation method of the process.

[0208] In the presence of water, Figure 1 The captured carbon dioxide is subjected to an electrochemical reduction step 12.1 to obtain an intermediate product mixture. The product mixture is then subjected to a separation step 12.2 to separate the ethylene contained in the intermediate product mixture. Steps 12.1 and 12.2 are Figure 1 A specific embodiment of the transformation step 2(i) is shown.

[0209] The ethylene thus obtained is subsequently subjected to an oxidation step 13.1 to produce ethylene oxide, which is treated with water in a hydrolysis step 13.2 to produce monoethylene glycol as an ethylene derivative. Steps 13.1 and 13.2 are Figure 1 A specific embodiment of the optional derivatization step 3.

[0210] In the following, in a polymerization step 14.1, monoethylene glycol is polymerized with terephthalic acid to produce polyethylene terephthalate (PET), and / or in a polymerization step 14.2, monoethylene glycol is polymerized with 2,5-furandicarboxylic acid to produce polyethylene furandicarboxylate (PEF). Steps 14.1 and 14.2 are Figure 1 A specific embodiment of the optional polymerization step 4.

[0211] Figure 5 Shows the display Figure 4 Flow chart of a further embodiment of a process, in which, in addition to PET and PEF, ethylene in the ethylene-containing mixture as well as all by-products are recycled, converted into less problematic substances or used for further applications.

[0212] Specifically, in the presence of water, Figure 1The captured carbon dioxide is subjected to an electrochemical reduction step 12.1 to obtain an intermediate product mixture. The product mixture is then subjected to a separation step 12.2 to separate the ethylene, oxygen, formate, formic acid, carbon monoxide (CO), hydrogen, methane, and alcohols contained in the intermediate product mixture. Suitable methods for separating and isolating these substances are known to those skilled in the art.

[0213] The separated ethylene is then Figure 4 The same process is described to produce PET and / or PEF.

[0214] The oxygen may be used for the derivatization of ethylene in step 13.1 and / or it may be used for other applications.

[0215] Formate (which exists as sodium formate) can be decomposed when heated to >300°C, eliminating hydrogen and monoxide (1:1) and leaving Na2CO3, especially by thermolysis step 16. Formic acid can decompose into carbon dioxide and hydrogen and / or into carbon monoxide and water in step 16, depending on the temperature and the type of catalyst used. Both reactions are in equilibrium.

[0216] The products of the pyrolysis step 16 and additional carbon monoxide and hydrogen separated from the intermediate product mixture may be reacted in a hydrogenation step 17 to produce methanol.

[0217] Likewise, the methane separated from the intermediate product mixture can be decomposed into hydrogen and carbon (C) in a decomposition step 18. The carbon can be stored and thus removed from the atmosphere over the long term. The hydrogen obtained in this process can be reused in a hydrogenation step 17, or it can be used for other applications.

[0218] The alcohols contained in the intermediate product mixture are used, for example, in the chemical industry.

[0219] use Figure 5 According to the process shown, all components contained in the intermediate product mixture can be used as such and / or converted into other useful substances.

[0220] However, the present invention is not limited to the examples shown in the specific embodiments. For example, other polymeric substances can be produced instead of PET and PEF, such as polyethylene, polypropylene, polystyrene, polyacrylonitrile and more polymeric substances.

[0221] In addition, the polymeric substances produced by the process of the present invention can be further converted into other products. For example, polyacrylonitrile can be converted into carbon fibers, which can be used as reinforcing members in building materials and / or for industrial applications.

[0222] Figure 6A flow diagram showing the production of carbon fibers or carbon fiber reinforced polymers is shown. Thus, in the derivatization unit 3, the carbon fibers of the conversion units 2(i) or 2(ii) (see Figure 1 ) is converted into acrylonitrile. Subsequently, the acrylonitrile is polymerized in the polymerization unit 4 to form polyacrylonitrile.

[0223] In a further step, the polyacrylonitrile is decomposed to form carbon fibers in a pyrolysis unit 5. Optionally, the carbon fibers can be embedded in a polymeric material (which can also be produced using the process of the invention or other processes) to form a carbon fiber reinforced polymer.

[0224] The carbon fibers or carbon fiber-reinforced polymers thus obtained can, for example, be used for applications in the aerospace industry, the automotive industry and / or civil engineering, for example as reinforcement in construction materials such as mortar or concrete structures.

[0225] Carbon fibers and carbon fiber-reinforced polymers can be produced in a CO2-negative manner. This, in turn, can reduce the carbon footprint of products containing these ingredients.

Claims

1. A process for producing a polymer product with negative carbon dioxide emissions, comprising the following steps: a) capturing carbon dioxide from gases containing carbon dioxide, in particular from air or exhaust gases (1, 11.1, 11.2), in particular by direct air capture; b) converting at least a portion of the captured carbon dioxide (2, 12.1) into intermediate products comprising olefins, in particular ethylene and / or propylene; preferably, by: (i) electrochemical reduction of carbon dioxide in the presence of water (2i, 12.1); and / or (ii) hydrogenation of carbon dioxide (2ii) with hydrogen to form methanol and subsequent conversion of the methanol to olefins, preferably by: Methanol to olefins (MTO); and / or ●Methanol to gasoline reaction (MTG); c) optionally, subjecting the olefins of the intermediate product to a derivatization reaction (3, 13.1, 13.2) to obtain olefin derivatives, in particular diols and / or acrylonitrile; d) further polymerizing the olefin and / or olefin derivative, in particular with at least one other monomer (4, 14.1, 14.2) to obtain a polymer product; Therein, at least for step a), in particular at least for steps a) and b), and especially for all steps a) to d), the energy required for carrying out one or more process steps is provided in the form of renewable energy.

2. The process according to claim 1 , further comprising a step of generating said renewable energy, in particular using photovoltaic units and / or wind power units and / or solar thermal collectors, in particular, wherein said energy is generated in a plant where step a), in particular steps a) and b) or all steps are performed.

3. Process according to any of the preceding claims, wherein in process step a), in a first stage, the gas comprising carbon dioxide is contacted with sodium hydroxide, in particular a sodium hydroxide solution and / or solid sodium hydroxide, to absorb carbon dioxide and form sodium carbonate, and in a second stage, gaseous carbon dioxide and sodium hydroxide, in particular a sodium hydroxide solution, are formed from the sodium carbonate obtained in the first stage and / or the sodium bicarbonate converted from the sodium carbonate obtained in the first stage, in particular at a temperature below 350° C., preferably below 250° C., for example between 50° C. and 200° C., more preferably between 90° C. and 200° C.

4. The process according to claim 1 , wherein step b) is carried out according to option (i) to obtain a mixture comprising ethylene and at least one compound selected from the group consisting of oxygen, formic acid, formates, carbon monoxide, hydrogen, methane and / or lower alcohols.

5. The process according to claim 4, wherein formic acid and / or formates are decomposed into carbon monoxide and hydrogen.

6. A process according to any one of claims 4 to 5, wherein methane is decomposed into carbon and hydrogen.

7. The process according to claim 4 , wherein hydrogen is reacted with carbon monoxide to form methanol, the carbon monoxide originating directly from a mixture comprising ethylene and / or from the decomposition of formic acid and / or formate, and / or wherein the hydrogen originates directly from a mixture comprising ethylene and / or from the decomposition of methane.

8. Process according to any of the preceding claims, wherein step b) is carried out according to option (ii) and carbon dioxide is subjected to a catalytic hydrogenation reaction to obtain methanol, using a Cu-based catalyst and / or an In2O3-based catalyst, in particular Cu / ZnO / Al2O3.

9. The process according to claim 1 , wherein step b) is carried out according to option (ii) and the methanol obtained is converted into olefins, in particular ethylene and / or propylene, in a methanol to olefins reaction using a zeolite catalyst, in particular a silicoaluminophosphate zeolite catalyst.

10. Process according to any of the preceding claims, wherein step b) is carried out according to option (ii) and the methanol obtained is converted into olefins, in particular ethylene and / or propylene, in a methanol-to-gasoline reaction using an aluminosilicate catalyst, such as ZSM-5.

11. The process according to any one of the preceding claims, wherein in step c), the ethylene obtained in step b) is reacted with oxygen to obtain ethylene oxide, and the ethylene oxide thus obtained is reacted to give monoethylene glycol.

12. The process according to any of the preceding claims, wherein in step c), the propene obtained in step b) is subjected to an ammoxidation reaction to form a nitrile, in particular acrylonitrile.

13. The process according to claim 1 , wherein in step d), the diol obtained, in particular monoethylene glycol, is polymerized with terephthalic acid or 2,5-furandicarboxylic acid to obtain polyethylene terephthalate (PET) or polyethylene furandicarboxylate (PEF) as the polymer product.

14. Process according to claim 13, wherein the 2,5-furandicarboxylic acid is obtained from biomass, preferably from fructose, in particular via the intermediate compound 5-hydroxymethylfurfural.

15. The process according to any one of the preceding claims, wherein in step d) the olefin and / or the diol is converted into polyethylene glycol (PEG), polypropylene (PP) and / or polyethylene (PE).

16. A process according to any one of claims 12 to 15, wherein acrylonitrile is polymerised to form polyacrylonitrile.

17. The process of claim 16, wherein polyacrylonitrile is subjected to a pyrolysis reaction to form carbon fibers.

18. Process according to claim 17, wherein the carbon fibers, in particular in the form of composite materials and / or carbon fiber reinforced polymers, are mixed with a processable building material, in particular a processable mortar or concrete material, to produce building elements for buildings and / or infrastructure, such as foundations, supports, beams, walls, floors and / or ceilings.

19. The process of claim 18, wherein the processable building material comprises a geopolymer binder.

20. A building element obtainable by a process according to any one of claims 18 to 19.

21. An apparatus, in particular a chemical plant, in particular an apparatus for carrying out a process according to any one of claims 1 to 19, comprising: a) a capture unit (1), in particular a carbon dioxide adsorption unit, configured for capturing carbon dioxide from a gas comprising carbon dioxide, in particular from air or exhaust gas, in particular by direct air capture; b) a conversion unit (2) configured for converting at least a portion of the carbon dioxide captured by the capture unit into an intermediate product comprising olefins, in particular ethylene and / or propylene; Wherein the conversion unit preferably comprises: - a reduction unit (2i) for electrochemical reduction of carbon dioxide in the presence of water; and / or a hydrogenation unit (2ii) for hydrogenating carbon dioxide with hydrogen to form methanol and subsequently converting the methanol into olefins; c) an optional derivatization unit (3) for derivatizing at least a portion of the olefins in the intermediate product into olefin derivatives; d) a polymerization unit (4) for polymerizing the olefin and / or olefin derivative, in particular with at least one other monomer, to obtain a polymer product.

22. The device according to claim 21, further comprising an energy unit configured for generating renewable energy, in particular a photovoltaic unit, a solar thermal unit and / or a wind energy unit.

23. The device according to any one of claims 21 to 22, further comprising at least one unit selected from the following: a separation unit (12.2), in which by-products can be separated from the intermediate product comprising olefins, in particular at least one compound selected from the group consisting of oxygen, formic acid, formates, carbon monoxide, hydrogen, methane and / or lower alcohols; a decomposition unit (16) in which formic acid and / or formate are decomposed into carbon monoxide and hydrogen; - a decomposition unit (18) in which methane is decomposed into carbon and hydrogen; and - a synthesis unit (17) in which hydrogen and carbon monoxide are converted into methanol.

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