Electrical conversion of gaseous carbon dioxide via reduction in molten salt solution

Abstract

Sequestration and conversion of carbon dioxide by reduction in a metal-salt solution. A carbon dioxide raw material is passed through a reactor containing solvated electrons in a metal-salt solution. The solvated electrons react with carbon dioxide to form various carbon products. The solvated electrons can be regenerated simultaneously for continuous operation of the metal-salt reactor. In one embodiment, the embodiment relates to a method for forming carbon products from carbon dioxide. The method comprises the steps of passing carbon dioxide through a solution containing a metal that dissolves to produce solvated electrons, and regenerating the solvated electrons in the solution, the solvated electrons react with carbon dioxide to form at least one product containing carbon.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims the benefit and priority of U.S. Provisional Patent Application No. 63 / 581,212 filed on 7 September 2023, and the entire disclosure of that U.S. Provisional Patent Application is incorporated herein by reference in the same manner as if it were contained in its entirety.

[0002] Technical field The embodiments described herein generally relate to the capture, utilization, and sequestration of carbon dioxide, and more specifically, but are not limited to, the capture, utilization, and sequestration of carbon dioxide via reduction by solvated electrons in a molten salt solution, as well as the regeneration of solvated electrons in a molten salt solution. [Background technology]

[0003] background Decarbonization requires carbon capture, utilization, and sequestration technologies that are effective, economical, and technologically scalable. Plasma and aqueous chemical approaches are limited by low space-time yields and high activation energy dynamics, requiring high power consumption. Agricultural biological sequestration has enormous process times and does not capture carbon emissions at the source. Geological sequestration or mineralization requires large amounts of calcium or other reagents, which is uneconomical at the scale needed to address climate change.

[0004] Therefore, a technology for reducing carbon dioxide at a point source using renewable catalysts and reagents, and with favorable space-time yield and activation energy dynamics, is desirable. [Overview of the Initiative] [Means for solving the problem]

[0005] overview This summary is provided to introduce a set of simplified concepts, which will be further described in the following detailed sections. This summary is not intended to identify or exclude any major or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0006] In one embodiment, the embodiment relates to a method for forming carbon products from carbon dioxide. The method comprises the steps of passing carbon dioxide through a solution containing a metal that dissolves to generate solvated electrons, and regenerating the solvated electrons in the solution, the solvated electrons reacting with carbon dioxide to form at least one product containing carbon.

[0007] In some embodiments, solvated electrons are regenerated while carbon dioxide is flowing through the solution.

[0008] In some embodiments, solvated electrons are generated from the application of an electric current to the solution.

[0009] In some embodiments, the current is applied using at least one of the following: an immersion electrode, a plasma electrode, a Tesla coil, an electron beam generator, or an X-ray generator.

[0010] In some embodiments, solvated electrons arise from the dissolution of the electron donor.

[0011] In some embodiments, the electron donor is at least one of alkali metals, alkaline earth metals, or rare earth metals.

[0012] In some embodiments, the electron donor is one or more of sodium or barium.

[0013] In some embodiments, the solvated electron-containing solution comprises one or more of the following: sodium dissolved in sodium chloride, sodium dissolved in sodium bromide, sodium dissolved in sodium iodide, barium dissolved in barium chloride, barium dissolved in barium bromide, or barium dissolved in barium iodide.

[0014] In some embodiments, the current is applied using a plurality of immersion electrodes, and the method further includes the step of monitoring the voltage between at least two of the electrodes to detect the formation of undesirable by-products.

[0015] In some embodiments, the carbon-containing product is one or more of carbon monoxide, amorphous carbon, graphite, graphene, diamond, carbon nanotubes, hydrocarbons, or any other allotropes of carbon or carbon and oxygen.

[0016] In some embodiments, the method further includes the step of forming at least one byproduct containing oxygen.

[0017] In another embodiment, an embodiment of the present invention includes an apparatus for producing carbon products from carbon dioxide. The apparatus may comprise a reactor for a solution containing a metal and solvated electrons; a source of solvated electrons; and a bubbler for passing carbon dioxide through the solution, wherein the solvated electrons react with carbon dioxide to form at least one product containing carbon.

[0018] In some embodiments, the source of solvated electrons is operated while carbon dioxide is flowing through the solution.

[0019] In some embodiments, the source of solvated electrons is an electric current source.

[0020] In some embodiments, the current source is at least one of an immersion electrode, a plasma electrode, a Tesla coil, an electron beam generator, or an X-ray generator.

[0021] In some embodiments, the source of solvated electrons is a dissolved electron donor.

[0022] In some embodiments, the electron donor is at least one of an alkali metal, an alkaline earth metal, or a rare earth metal.

[0023] In some embodiments, the electron donor is one or more of sodium or barium.

[0024] In some embodiments, the solution containing solvated electrons comprises one or more of sodium dissolved in sodium chloride, sodium dissolved in sodium bromide, sodium dissolved in sodium iodide, barium dissolved in barium chloride, barium dissolved in barium bromide, or barium dissolved in barium iodide.

[0025] In some embodiments, the current source is a plurality of immersed electrodes, and the apparatus further comprises a voltmeter configured to measure a voltage between at least two of said electrodes to detect formation of undesirable by-products.

[0026] In some embodiments, the at least one carbon-containing product is one or more of carbon monoxide, amorphous carbon, graphite, graphene, diamond, carbon nanotubes, hydrocarbons, or any other allotrope of carbon or carbon and oxygen.

[0027] In some embodiments, solvated electrons react with carbon dioxide to form at least one oxygen-containing by-product.

[0028] Non-limiting and non-exhaustive embodiments of the present disclosure are described with reference to the following drawings, wherein like reference numerals refer to like parts throughout the various figures unless otherwise specified. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] [Figure 1]Figure 1 is a flowchart illustrating one embodiment of a method for reducing carbon dioxide in metal and salt solutions.

[0030] [Figure 2] Figure 2 is a block diagram showing one embodiment of an apparatus for reducing carbon dioxide in metal and salt solutions.

[0031] [Figure 3] Figure 3 is a process flow diagram showing the reactor operation along with the regeneration of solvated electrons. [Modes for carrying out the invention]

[0032] Detailed explanation Various embodiments are described more fully with reference to the accompanying drawings, which form part of this specification and illustrate specific exemplary embodiments. However, the concepts of this disclosure can be practiced in many different forms and should not be construed as being limited to the embodiments described herein. Rather, these embodiments are provided as part of a thorough and complete disclosure to fully convey to those skilled in the art the concepts, technology and scope of practice of this disclosure. Embodiments can be practiced as methods, systems or devices. Accordingly, the following detailed description should not be construed as restrictive.

[0033] Any reference in this specification to “one embodiment” or “a particular embodiment” means that certain features, structures, or characteristics described in relation to that embodiment are included in at least one exemplary embodiment or technique provided by this disclosure. The phrase “in one embodiment” appearing in various parts of this specification does not necessarily refer to the same embodiment.

[0034] Furthermore, the language used herein has been selected, in principle, for readability and teaching purposes, and not to define or delineate the disclosed subject matter. Accordingly, this disclosure is intended to be illustrative and not to limit the scope of the concepts discussed herein. definition

[0035] Unless otherwise specified, the following terms, when used herein, shall have the meanings set forth below.

[0036] The term "carbon dioxide feedstock" refers to feedstock for a process that contains at least partially carbon dioxide (CO2). The feedstock can be a stream containing at least partially CO2 in any phase.

[0037] The term “carbon products” or “carbon-containing products” refers to any partially reduced allotrope of carbon. This definition excludes CO2 but includes carbon monoxide (CO), carbonates, hydrocarbons, any carbon-oxygen compounds or polymers having at least one hydrogen or other functional group, as well as allotropes of carbon, including but not limited to graphite, graphene, diamond, and carbon nanotubes.

[0038] The term "metal halide" refers to a class of salts containing at least one metal cation species and at least one halide anion species. The metal species can be selected from any group of metals on the periodic table, but particularly from alkali metals, alkaline earth metals, and rare earth metals. Examples of halide anion species, though not limited to these, include fluorides, chlorides, bromides, and iodides. Metal halides are generally given the formula MX i This can be explained by the formula, where M refers to a metal cation species, X refers to a halide anion species, and an integer i is chosen to equilibrium the charge of the compound.

[0039] The term "metal-salt solution" refers to a solution formed from at least one metal halide species and at least one metal species. The solution may be heated to be in a liquid or molten state. The metals are selected to dissolve in the metal salt solution and form free cationic metal species and solvated electrons.

[0040] The term "solvated electrons" refers to free electrons in a metal-salt solution formed from the dissolution of at least one metal species.

[0041] The term "reactor" refers to any suitable process unit or reactor that brings a carbon dioxide raw material into contact with a metal-salt solution for the reduction of CO2. Embodiment

[0042] Embodiments of the present invention include methods and apparatus configurations aimed at converting carbon dioxide (CO2) into carbon products via reduction in a metal-salt solution.

[0043] Figure 1 is a flowchart illustrating one embodiment of a process 100 for reducing carbon dioxide in a metal-salt solution. In outline, a carbon dioxide raw material is flowed through a metal-salt solution 104. By dissolving the metal in the same metal-salt solution, solvated electrons are generated 108. The solvated electrons react with carbon dioxide to form a carbon-containing product 112.

[0044] Figure 2 is a flowchart illustrating the apparatus 200 for carrying out the method of Figure 1. A metal-salt solution is introduced into the reactor 204. Solvated electrons are generated in the metal-salt solution via the current source 208. A type of injector 212 introduces carbon dioxide raw material into the solution. The reactor is then maintained under process conditions that facilitate the reaction between the carbon dioxide raw material and the solvated electrons in the solution.

[0045] Figure 3 shows a process flow diagram of the apparatus of Figure 2 that achieves the reduction of carbon dioxide in a metal halide solution. The metal halide solution 308 and the metal 312 are introduced into the reactor 204. An electric current is applied to the solution, for example using one or more immersion electrodes, to generate solvated electrons 316. The carbon dioxide raw material is bubbling into the reactor 320. After reaction with the solvated electrons, the carbon dioxide is reduced to at least carbon monoxide and other carbon products 324. The metal halide solution may be recycled 328. The metal is oxidized to produce metal oxide products 332. raw material

[0046] In embodiments of this process, a feedstock containing at least partially CO2 is selected. The feedstock can be any phase, including solid, liquid, and gaseous phases. The feedstock may be pure CO2, or it may be a mixed stream of CO2 and other gases or liquids. For example, gas effluents from reactors containing CO2, other combustion products containing carbon, and other gaseous species such as nitrogen are all suitable feedstocks. If necessary, the other gases and liquids may be inert and nonreactive with the chemicals in the process.

[0047] In embodiments of the present invention, the raw materials are introduced into the reactor by a suitable method based on the phase of the raw materials. In embodiments where the raw materials are gaseous or vapor phase effluents, the raw materials can be bubbling through a liquid or molten metal-salt solution. In embodiments where the raw materials are liquid, the raw materials may be flowed through or mixed in a metal-salt solution. Metal-salt solution

[0048] In embodiments of this process, a metal-salt solution is formed by adding a certain amount of a suitable metal to a salt solution. A metal that dissolves at least partially in the salt solution is preferred. This dissolution generates metal cation species and solvated free electrons, thus causing the metal to act as an electron donor.

[0049] In some embodiments, the electron donor metal is at least one of alkali metals, alkaline earth metals, or rare earth metals. Preferred rare earth metals include yttrium (Y) and lanthanides. In other embodiments, any preferred metal from the s-, p-, d-, and f- blocks of the periodic table can be used as an electron donor, provided that process conditions are selected so that the metal can dissolve in the salt solution.

[0050] In some embodiments, the electron donor metal is at least one of sodium (Na), potassium (K), calcium (Ca), barium (Ba), bismuth (Bi), strontium (Sr), lanthanum (La), praseodymium (Pr), and neodymium (Nd).

[0051] In some embodiments, the salt solution is formed by selecting a metal halide salt in which the metal species matches the electron-donating metal, and the halide is at least one of fluoride, chloride, bromide, or iodide.

[0052] In some embodiments, the metal-salt solution may be heated to a liquid state. The operating temperature of the metal-salt solution may be selected to facilitate the dissolution of the metal into solvated metal cations and solvated electrons. The salt may be heated, if necessary, until it forms a liquid solution. In some embodiments, the salt solution may be liquid or held under temperature and pressure process conditions that allow for the dissolution of the electron-donating metal. In some embodiments, the metal may be a solid dispersed in the liquid salt solution.

[0053] In some embodiments, the salt solution may consist of an alkali or alkaline earth salt, such as at least one of NaCl, KCl, CaCl2, or NaI, but not limited to these. In other embodiments, the salt solution may consist of another metal halide salt, such as at least one of BaCl2, BiCl3, and BaI2. A mixture of metal halides may be used to regulate the temperature at which the solution melts and increases the solubility of the electron-donating metal. For example, a combination of at least two of metal chlorides, metal bromides, and metal iodides may be present.

[0054] In other embodiments, the liquid solution may contain ammonia (NH3) or another solvent, insofar as it is compatible with the selected metal species. Compatibility is determined by whether the metal dissolves in the solvent to generate solvated electrons, and whether undesirable byproducts are produced by the reaction of the solvent with either the metal or carbon raw material.

[0055] In some embodiments, the metal-salt solution is composed of metallic Na dissolved in molten NaCl, where metallic Na is in a solution of NaCl. + It dissolves in cations and solvated electrons. In some embodiments, the metal-salt solution consists of metallic Ca and molten CaCl2, and dissolved Ca 2+ and solvated electrons are formed. In some embodiments, the metal-salt solution consists of metallic Bi and molten BiCl3, and dissolved Bi 3+ and solvated electrons are formed. In some embodiments, the metal-salt solution consists of metallic Ba and molten BaCl2, and dissolved Ba 2+ and solvated electrons are formed. In some embodiments, the metal-salt solution consists of metallic Na and molten NaI, and dissolved Na + And they form solvated electrons. Carbon conversion

[0056] In embodiments of the present invention, the carbon dioxide raw material is passed through a metal-salt solution containing solvated electrons.

[0057] In some embodiments, the process of flowing carbon dioxide through a metal-salt solution involves bubbling gaseous or vapor-phase carbon dioxide through a liquid metal-salt solution. Other embodiments may involve flowing carbon dioxide onto or through a metal-salt solution. In yet other embodiments, a mixer or other method of stirring and mixing the carbon dioxide source and the metal-salt solution may be used.

[0058] In solution, solvated electrons react with CO2 to form carbon-containing products. In some embodiments, the primary chemical phenomenon is the reduction of carbon dioxide (CO2) to carbon monoxide (CO). Oxygen reacts with metal cation species to form metal oxides. In some embodiments, the metal oxides may precipitate as solids. In some embodiments, the metal oxides may be soluble.

[0059] In various embodiments, the product may include carbon monoxide; carbonates and any other allotropes of carbon and oxygen; and elemental carbon, including amorphous carbon, graphite, graphene, diamond, carbon nanotubes, hydrocarbons, or any other allotropes of carbon.

[0060] In some embodiments, the above combination of products can be produced in a single pass through the reactor.

[0061] In some embodiments, these carbon products may then be intermediates and may be further used as raw materials for the production of other carbon products such as graphite, graphene, carbon nanotubes, and synthetic diamond. By-products

[0062] In some embodiments, byproducts may be generated from the reaction of solvated electrons with carbon dioxide raw materials or other chemical species present in the metal-salt solution. While metal oxides may be the main byproducts, additional oxygen-containing intermediate products such as metal carbonate species may also be produced.

[0063] In some embodiments, the soluble metal oxide product consists of a metal cation and a dissolved oxygen anion (O2- can be redissolved in ). When an electric current is applied to the solution, O at the anode 2- can be converted into oxygen gas (O2), and metal cations can be reduced to elemental metal at the cathode.

[0064] In embodiments where water is present in the solution, byproducts including aldehydes, carboxylic acids, and other hydrocarbons may be produced. Regeneration of solvated electrons

[0065] In some embodiments, solvated electrons can be regenerated during the conversion of carbon dioxide to enable a continuous process.

[0066] In some embodiments, the metal may be added continuously or periodically during operation, and dissolution of the metal into the solution regenerates the supply of solvated electrons.

[0067] In some embodiments, solvated electrons can be regenerated through a Faradaic reaction. An electric current is applied to the solution at a potential greater than the activation energy required to reduce metal ions to metal. The potential may also be selected to be less than the activation energy for undesirable side reactions such as decomposition of metal halides.

[0068] For example, in embodiments where a Ba-BaCl2 metal-salt solution is used with an immersion electrode, reduction of CO2 to CO results in the formation of BaO as a product. BaO is soluble in BaCl2, and Ba 2+ cations and O 2- anions are formed. Application of a current at a suitable voltage allows reduction of Ba 2+ to Ba metal at the cathode, and oxidation of O 2- to O2 gas at the anode.

[0069] In some embodiments, the current is applied using at least one of an immersion electrode, a plasma electrode, a Tesla coil, an electron beam generator, or an X-ray generator. The electrode material may be graphite, titanium diboride, platinum, or any other chemically inert material.

[0070] In some embodiments, a pressure swing adsorption reaction may be used to regenerate solvated electrons.

[0071] In some embodiments, a degassing reaction may be used to regenerate solvated electrons. In this embodiment, argon (Ar) or another inert gas may be bubbled through the CO product to carry CO out of the reactor and release solvated electrons.

[0072] In some embodiments, high-voltage electrodes may be used to generate plasma by applying a high voltage to a solution or a gas adjacent to a solution. The plasma can generate free radicals and solvated free electrons.

[0073] In some embodiments, any type of electron beam can introduce fresh solvated electrons into a metal-salt solution. Process control

[0074] In some embodiments, the temperature of the solution is maintained by the heat of the effluent bubbling into the solution.

[0075] In some embodiments, the temperature of the liquid solution is maintained by waste heat generated by applying an electric current to the liquid solution.

[0076] In some embodiments, the current applied to the metal-salt solution is monitored, and the voltage between electrodes is used to detect when undesirable byproducts may form. The applied potential may be limited to prevent the formation of such byproducts. For example, the applied potential may be set within a range that promotes the dissolution of the metal into solvated electrons but is below the applied potential required to decompose the metal halide constituting the salt solution.

[0077] In some embodiments, the measurement may be performed on carbon products generated by the reactor, such as but not limited to CO. This data can be used to control the input to the regeneration reaction in order to maintain a desired concentration of solvated electrons. others

[0078] In some embodiments, catalysts, additional solvents, and other solubilants may be present as needed to increase the solvated electron concentration. In some embodiments, catalysts, additional solvents, and other solubilants may be present as needed to promote the formation of specific carbon products.

[0079] Embodiments of the present invention also include systems, machines, and controls for achieving the above method. Equivalents

[0080] The methods, systems, and devices discussed above are examples. Various configurations may be made by omitting, substituting, or adding various procedures or components as appropriate. For example, in an alternative configuration, the method may be performed in a different order than described, and various steps may be added, omitted, or combined. Also, features described for a particular configuration may be combined for various other configurations. Different aspects and elements of a configuration may be combined in a similar manner. Furthermore, technology is advancing, and therefore many of the elements are examples and do not limit the scope of this disclosure or the claims.

[0081] For example, embodiments of the present disclosure are described above with reference to block diagrams and / or operation diagrams of methods, systems, and computer program products according to embodiments of the present disclosure. The functions / actions described in the blocks may be performed in an order other than that shown in any flowchart. For example, depending on the functions / actions involved, two consecutively shown blocks may actually be executed substantially simultaneously, or the blocks may be executed in reverse order. Additionally or alternatively, not all of the blocks shown in any flowchart must be performed and / or executed. For example, if a given flowchart has five blocks containing functions / actions, only three of the five blocks may be performed and / or executed. In this example, any three of the five blocks may be performed and / or executed.

[0082] The statement that a value exceeds (or is greater than) a first threshold is equivalent to the statement that the value satisfies or exceeds a second threshold that is slightly greater than the first threshold, for example, the second threshold being one value higher than the first threshold in the resolution of the relevant system. The statement that a value is less than (or less than) a first threshold is equivalent to the statement that the value is less than or equal to a second threshold that is slightly lower than the first threshold, for example, the second threshold being one value lower than the first threshold in the resolution of the relevant system.

[0083] Certain details are provided in the description to provide a thorough understanding of the exemplary configurations (including their implementation). However, the configurations can be implemented without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques are shown without unnecessary details to avoid obscuring the configurations. This description provides only exemplary configurations and does not limit the claims, applicability, or configurations. Rather, the foregoing description of configurations provides to those skilled in the art a feasible explanation for implementing the described techniques. Various modifications to the function and arrangement of elements may be made without departing from the spirit or scope of this disclosure.

[0084] While several exemplary configurations have been described, various modifications, alternative structures, and equivalents can be used without departing from the spirit of this disclosure. For example, the elements described above may be components of a larger system, other rules may take precedence over various implementations or applications of the technology of this disclosure, or they may be modified in other ways. Also, several steps may be taken before, during, or after the elements described above are considered.

Claims

1. A method for forming carbon products from carbon dioxide, wherein the method is The steps include: passing carbon dioxide through a solution containing a metal that dissolves and generates solvated electrons; A step of regenerating the solvated electrons in the solution. A method comprising a solvated electron reacting with carbon dioxide to form at least one product containing carbon.

2. The method according to claim 1, wherein the solvated electrons are regenerated while carbon dioxide is flowing through the solution.

3. The method according to claim 1, wherein the solvated electrons are generated from the application of an electric current to the solution.

4. The method according to claim 3, wherein the current is applied using at least one of an immersion electrode, a plasma electrode, a Tesla coil, an electron beam generator, or an X-ray generator.

5. The method according to claim 1, wherein the solvated electrons are generated from the dissolution of the electron donor.

6. The method according to claim 5, wherein the electron donor is at least one of alkali metals, alkaline earth metals, or rare earth metals.

7. The method according to claim 5, wherein the electron donor is one or more of sodium or barium.

8. The method according to claim 7, wherein the solvated electron-containing solution comprises one or more of the following: sodium dissolved in sodium chloride, sodium dissolved in sodium bromide, sodium dissolved in sodium iodide, barium dissolved in barium chloride, barium dissolved in barium bromide, or barium dissolved in barium iodide.

9. The method according to claim 4, wherein the current is applied using a plurality of immersion electrodes, and the method further includes the step of monitoring the voltage between at least two of the electrodes to detect the formation of an undesirable by-product.

10. The method according to claim 1, wherein the at least one carbon-containing product is one or more of carbon monoxide, amorphous carbon, graphite, graphene, diamond, carbon nanotubes, hydrocarbons, or any other allotropes of carbon or oxygen.

11. The method according to claim 1, further comprising the step of forming at least one by-product containing oxygen.

12. An apparatus for producing carbon products from carbon dioxide, wherein the apparatus is Reactors for solutions containing metals and solvated electrons; The source of the solvated electrons; A bubbler for flowing carbon dioxide through the aforementioned solution An apparatus comprising the solvated electrons reacting with the carbon dioxide to form at least one product containing carbon.

13. The apparatus according to claim 12, wherein the source of solvated electrons is operated while carbon dioxide is flowing through the solution.

14. The apparatus according to claim 12, wherein the source of solvated electrons is a current source.

15. The apparatus according to claim 14, wherein the current source is at least one of an immersion electrode, a plasma electrode, a Tesla coil, an electron beam generator, or an X-ray generator.

16. The apparatus according to claim 12, wherein the source of solvated electrons is a dissolved electron donor.

17. The apparatus according to claim 16, wherein the electron donor is at least one of alkali metals, alkaline earth metals, or rare earth metals.

18. The apparatus according to claim 16, wherein the electron donor is one or more of sodium or barium.

19. The method according to claim 18, wherein the solvated electron-containing solution comprises one or more of the following: sodium dissolved in sodium chloride, sodium dissolved in sodium bromide, sodium dissolved in sodium iodide, barium dissolved in barium chloride, barium dissolved in barium bromide, or barium dissolved in barium iodide.

20. The apparatus according to claim 15, wherein the current source is a plurality of immersion electrodes, and the apparatus further comprises a voltmeter configured to measure the voltage between at least two of the electrodes to detect the formation of undesirable by-products.

21. The apparatus according to claim 12, wherein the at least one carbon-containing product is one or more of carbon monoxide, amorphous carbon, graphite, graphene, diamond, carbon nanotubes, hydrocarbons, or any other allotropes of carbon or oxygen.

22. The apparatus according to claim 12, wherein the solvated electrons react with carbon dioxide to form at least one byproduct containing oxygen.

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