Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B1/00—Electrolytic production of inorganic compounds or non-metals
  • C25B1/01—Products
  • C25B1/02—Hydrogen or oxygen
  • C25B1/04—Hydrogen or oxygen by electrolysis of water
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/42—Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
  • B01D61/44—Ion-selective electrodialysis
  • B01D61/445—Ion-selective electrodialysis with bipolar membranes; Water splitting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/42—Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
  • B01D61/44—Ion-selective electrodialysis
  • B01D61/46—Apparatus therefor
  • B01D61/50—Stacks of the plate-and-frame type
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B1/00—Electrolytic production of inorganic compounds or non-metals
  • C25B1/01—Products
  • C25B1/14—Alkali metal compounds
  • C25B1/16—Hydroxides
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B1/00—Electrolytic production of inorganic compounds or non-metals
  • C25B1/01—Products
  • C25B1/23—Carbon monoxide or syngas
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B15/00—Operating or servicing cells
  • C25B15/08—Supplying or removing reactants or electrolytes; Regeneration of electrolytes
  • C25B15/081—Supplying products to non-electrochemical reactors that are combined with the electrochemical cell, e.g. Sabatier reactor
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B15/00—Operating or servicing cells
  • C25B15/08—Supplying or removing reactants or electrolytes; Regeneration of electrolytes
  • C25B15/087—Recycling of electrolyte to electrochemical cell
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
  • C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
  • C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2311/00—Details relating to membrane separation process operations and control
  • B01D2311/06—Specific process operations in the permeate stream
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2311/00—Details relating to membrane separation process operations and control
  • B01D2311/08—Specific process operations in the concentrate stream
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2311/00—Details relating to membrane separation process operations and control
  • B01D2311/26—Further operations combined with membrane separation processes
  • B01D2311/263—Chemical reaction
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P7/00—Preparation of oxygen-containing organic compounds
  • C12P7/02—Preparation of oxygen-containing organic compounds containing a hydroxy group
  • C12P7/04—Preparation of oxygen-containing organic compounds containing a hydroxy group acyclic
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P7/00—Preparation of oxygen-containing organic compounds
  • C12P7/40—Preparation of oxygen-containing organic compounds containing a carboxyl group including Peroxycarboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
  • C25B9/05—Pressure cells

Definitions

• the invention relates to a system to convert carbon dioxide. Further, the present invention provides a method to convert carbon dioxide electrochemically.
• EP3741864A1 describes an invention that relates to a method for production of organic acid and/or alcohol comprising the steps of: a) providing a basic, aqueous medium containing carbon dioxide in the form of hydrogen carbonate-anions and/or carbonate-anions; b) feeding the basic, aqueous medium containing the carbon dioxide of step (a) into a bipolar membrane electrodialysis unit comprising an anode, a cathode, an ion-selective anion- exchange membrane, and two water-dissociating bipolar membranes, capable of providing for an acidic compartment between the water-dissociating bipolar membrane on the anode side and the ion-selective anion-exchange membrane and for a basic compartment between the waterdissociating bipolar membrane on the cathode side and the ion-selective anion-exchange membrane; c) transporting the carbon dioxide in the form of hydrogen carbonate-anions and/or carbonate-anions across the ani
• Carbon capture technologies are known in the art. However, these technologies for carbon dioxide capture rely predominantly on absorption of carbon dioxide from flue gas. Flue gas or pollutants such as from the industry or automobiles may be a rich source of carbon. However, there is also carbon dioxide in the atmosphere and dissolved in the ocean. While it is of interest to capture the carbon dioxide from dilute sources, most prior art systems are configured to capture carbon dioxide from carbon rich sources and may not be as effective in capturing carbon dioxide from relatively dilute sources.
• Carbon dioxide in its gaseous form is non-reactive under ambient conditions.
• carbon monoxide is an important component (for example: synthesis gas, producer gas and water gas) for the manufacture of many hydrocarbons. Further, it is also an effective reducing agent for the reduction of metallic oxides to their base metals. Further, carbon monoxide is used in the manufacture of hydrocarbons and their oxygen derivatives from a combination of hydrogen and carbon monoxide.
• Carbon dioxide electrolyzers are known in the art and have been used to reduce captured carbon dioxide into carbon monoxide. However, this technology is still in its infancy and hence not sufficiently energy efficient to close the carbon cycle. Further, it may not be profitable to operate i.e. for the capture of carbon dioxide and producing industrially viable (and commercially profitable) end products.
• Drawbacks of a carbon dioxide electrolyzer using a vapor-phase CO2 may be water management of the gas diffusion electrode, and/or the relatively high crossover of carbonic species to the anolyte.
• a separate CO2 capture step, releasing the CO2 in gas state, and subsequent conversion in another reactor, may require substantial energy to release the CO2 from the capture medium.
• the present invention may have as object to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.
• the invention may be a system for providing carbon monoxide and hydrogen.
• the system may comprise an electrical cell comprising system.
• the electrical cell comprising system may comprise a carbon dioxide electrolysis unit.
• the carbon dioxide electrolysis unit may comprise an anode, a cathode, and an ion-exchange membrane.
• the ion-exchange membrane may further comprise a cation-exchange membrane (or “CEM”), or an anion-exchange membrane (or “AEM”), or a bipolar membrane.
• CEM cation-exchange membrane
• AEM anion-exchange membrane
• the carbon dioxide electrolysis unit may be configured to apply a potential difference selected from the range of 1-4V, such as especially 1.5-3V across the anode and the cathode of the carbon dioxide electrolysis unit.
• the system may be configured to convert in a first conversion process a carbon comprising stream to provide: (i) a carbon monoxide comprising stream, and (ii) an alkaline solution.
• the carbon comprising stream may comprise one or more of carbon dioxide (CO2), carbonate ions (CO3 2 ), and bicarbonate ions (HCO3 ) in an aqueous solution.
• the term “hydrogen carbonate ions” may also be used to refer to bicarbonate ions.
• the system may be configured to electrolyze water in a second conversion process to provide a hydrogen comprising stream. Further, in embodiments, the system may be configured to execute the first conversion process and the second conversion process in the electrical cell comprising system. In embodiments, the system may be configured to pressurize one or more of (i) the carbon comprising stream, and (ii) the carbon monoxide comprising stream within at least part of the electrical cell comprising system. In further embodiments, the carbon comprising stream and/or the carbon monoxide comprising stream may be compressed at a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• the system may be configured to provide carbon monoxide and (optionally) hydrogen.
• the system may be configured to provide (only) carbon monoxide.
• the system may be configured to execute (only) the first conversion process in the electrical cell comprising system (thus providing carbon monoxide).
• the system may be configured to provide carbon monoxide and hydrogen.
• the system may be configured to execute the first conversion process and the second conversion process in the electrical cell comprising system (thus providing carbon monoxide and hydrogen). More especially, the system may execute the first conversion process independent of the second conversion process, and vice versa.
• the system may provide carbon monoxide independent of the production of hydrogen.
• electrolysis of carbon dioxide in an aqueous medium may (also) electrolyze water.
• hydrogen may (also) be provided as a byproduct during the electrolysis of carbon dioxide.
• the system may comprise a water electrolysis unit, wherein the water electrolysis unit may be configured to provide a (separate) hydrogen comprising stream (see further below).
• the system may be configured to provide carbon monoxide and (optionally) hydrogen.
• the carbon dioxide electrolysis unit may be configured to apply a potential difference selected from the range of 1-4V, such as 1.5-3V across the anode and the cathode of the carbon dioxide electrolysis unit.
• the system may be configured to convert in a first conversion process a carbon comprising stream to provide: (i) a carbon monoxide comprising stream, and (ii) an alkaline solution.
• the carbon comprising stream may comprise one or more of carbon dioxide (CCE), carbonate ions (CO3 2 ), and bicarbonate ions (HCO3 ) in an aqueous solution.
• CCE carbon dioxide
• CO3 2 carbonate ions
• HCO3 bicarbonate ions
• the term “hydrogen carbonate ions” may also be used to refer to bicarbonate ions.
• the invention provides a system for providing carbon monoxide, wherein the system comprises an electrical cell comprising system, wherein the electrical cell comprising system comprises a carbon dioxide electrolysis unit; wherein the carbon dioxide electrolysis unit comprises an anode, a cathode, an anodic compartment, a cathodic compartment and an ion-exchange membrane further comprising a cation-exchange membrane, or an anion-exchange membrane, or a bipolar membrane; wherein the carbon dioxide electrolysis unit is configured to apply a potential difference selected from the range of 1.5-3V across the anode and the cathode; wherein the system is configured to convert in a first conversion process a carbon comprising stream to provide: (i) a carbon monoxide comprising stream, and (ii) an alkaline solution; wherein the carbon comprising stream comprises one or more of carbon dioxide, carbonate ions, and bicarbonate ions in an aqueous solution; wherein a carbon comprising stream is provided to the anodic compartment
• the invention provides a system for providing carbon monoxide and hydrogen.
• the system comprises an electrical cell comprising system.
• the electrical cell comprising system comprises a carbon dioxide electrolysis unit.
• the carbon dioxide electrolysis unit comprises an anode, a cathode, and an ion-exchange membrane further comprising a cation-exchange membrane, or an anion-exchange membrane, or a bipolar membrane.
• the carbon dioxide electrolysis unit is configured to apply a potential difference selected from the range of 1.5-3 V across the anode and the cathode.
• carbon refers to the carbon present in the (chemical) compounds comprising carbon.
• carbonic species refers to dissolved carbon dioxide (CO2), bicarbonate (or “hydrogen carbonate”) ions (HCO3 ), and carbonate ions (CO3 2 ).
• the present invention may be a system that integrates the carbon capture and conversion into a single chemical process, which may effectively provide a higher energy efficiency, compared to executing these steps independently. Further, while most of the existing technology may be focused on executing a single step of the process, the present invention focusses on the complete process for the conversion of the source of carbon to the production of the final carbon-based chemicals.
• the capture of carbon dioxide in prior art systems have been discussed in the context of removing carbon dioxide from dense sources such as pollutants from industry or automobiles. However, the present system addresses the capture of carbon dioxide not only from dense carbon dioxide sources but also from dilute sources. Carbon dioxide may be captured from dilute sources via a water phase, where carbon dioxide is captured via a pH-swing.
• pH-swing refers to capturing carbon dioxide in an aqueous medium (for example an alkaline medium) and recovering the captured carbon dioxide by altering the pH of the medium.
• aqueous medium for example an alkaline medium
• medium may essentially also refer to a solution and may be used interchangeably as such.
• pH is known to the skilled person as the potential of hydrogen and is a quantitative measure of how acidic or basic a given solution is.
• a pH-swing may be achieved electrochemically by means such as electrolysis or bipolar membrane electrodialysis. pH plays an important role in the thermodynamic equilibrium of carbon dioxide, also referred to as “the carbonate equilibrium”.
• the total concentration of dissolved inorganic carbon (or “DIC”) is in dependence of the pH of the solution comprising carbon dioxide.
• Acidification of the solution leads to carbon dioxide gas out-gassing from the solution comprising carbon. Basification of the solution (or having a high pH value) leads to absorption of carbon dioxide gas increasing the DIC.
• carbon dioxide in the solution may exist in a plurality of forms i.e. it may exist as carbon dioxide gas (CO2), carbonate ions (CO3 2 ), or bicarbonate ions (HCO3 ).
• the dominant carbonic species may exist as carbon dioxide in acidic pH, bicarbonate ions in around neutral pH and carbonate ions in alkaline pH. The transition between the different species (or “carbonic species”) may not necessarily be sharp.
• a plurality of species may also coexist, for example an acidic solution at a pH of around 5 may comprise both dissolved carbon dioxide gas and bicarbonate ions.
• the carbonate equilibrium is the principal concept that allows for the capture and recovery of carbon dioxide. Since carbon dioxide is highly soluble in an alkaline medium, it may thus be captured in an alkaline medium (and exists primarily as carbonate ions). Further, altering the pH of this medium to an acidic (or low) pH value can change the dominant carbonic species to carbon dioxide gas, which may be easily out-gassed (i.e. released as carbon dioxide gas) and recovered from the medium.
• the present invention in embodiments may pressurize carbon dioxide in the aqueous medium. The pressurized carbon dioxide reduction may not only help increase current density but may also improve the selectivity of the reaction. Current density here refers to the amount of electric current flowing through a unit cross-sectional area.
• reaction selectivity may refer to in broad terms as being the result of making a reaction energetically favorable i.e., the method can be used to reduce carbon dioxide to carbon monoxide (in the carbon dioxide electrolysis unit) in favor of other reactions that may occur simultaneously (in the carbon dioxide electrolysis unit).
• carbon dioxide has high solubility at high pressure, which may ensure that the carbon dioxide remains dissolved during the electrolysis process.
• using an aqueous solution with highly concentrated dissolved inorganic carbon the water management of the reactive surface may be better controlled, allowing a larger catalytically active surface area.
• the use of a liquid can aid in the temperature control of the reactor.
• pressurizing a liquid comprising gasses may also be less energy- intensive than pressurizing a gas. Therefore, in embodiments, pressurizing a carbon comprising liquid (or a carbon comprising stream) i.e., the use of a pressurized liquid comprising carbon dioxide during electrolysis may also increase the energy efficiency of the system. Further, by pressurizing the liquid stream comprising carbon dioxide, the produced gaseous carbon monoxide stream after electrolysis may already be pressurized, thus requiring no additional energy for compression (for example the compression of carbon monoxide gas).
• the system may provide carbon monoxide and hydrogen. Carbon monoxide and hydrogen are important compounds required for the manufacture of many hydrocarbons using a variety of methods.
• the system may comprise an electrical cell comprising system.
• the electrical cell comprising system may further comprise other systems, particularly to carry out electrochemical reactions.
• more than one electrochemical reaction may be executed in the plurality of systems comprised by the electrochemical system. This may provide the advantage of configuring these systems in an efficient manner. Efficient manner here may refer to the efficient spatial configuration such as placing multiple related system in the same space, which may be useful especially when these related systems may have similar requirements such as power lines, chimneys, flow channels, etc.
• the electrical cell comprising system may comprise a carbon dioxide electrolysis unit.
• the carbon monoxide comprising stream may optionally further comprise one or more of ethylene, formic acid, hydrogen and ethanol.
• unreacted carbon dioxide may be present in the carbon monoxide comprising stream.
• a ratio of a volume percentage of carbon monoxide of the carbon comprising stream to a volume percentage of carbon monoxide in the carbon monoxide comprising stream is ⁇ 0.1, such as ⁇ 0.01.
• the volume percentage of carbon monoxide of the carbon comprising stream may be essentially 0 vol.%.
• the carbon dioxide electrolysis unit may comprise an anode, a cathode, and an ion-exchange membrane.
• the carbon dioxide electrolysis unit may comprise two compartments, an anodic compartment, and a cathodic compartment.
• the anode may be configured in the anodic compartment and the cathode may be configured in the cathodic compartment.
• the anodic compartment and the cathodic compartment may be separated by means of an ion-exchange membrane.
• Ion-exchange membranes may be semi-permeable membranes that are selectively permeable to certain compounds.
• the ion-exchange membranes may contain pores that may limit the transfer of certain species of compounds or ions based on their molecular size.
• the ion-exchange membranes may be charged and hence may repel or attract certain charged species or ions.
• the ion-exchange membrane may help facilitate reactions by controlling the exposure of certain compounds or species to the cathode or the anode in the carbon dioxide electrolysis unit. This may provide the advantage of restricting certain compounds or ions to the anodic or cathodic compartments, thus improving reaction selectivity. Subsequently, this may provide the advantage of increasing the yield of certain desirable products, such as the production of carbon monoxide in the carbon dioxide electrolysis unit.
• the ion-exchange membranes may further comprise a cationexchange membrane, or an anion-exchange membrane, or a bipolar membrane.
• the carbon dioxide electrolysis unit may be configured to apply a potential difference selected from the range of 1.5-3 V across the anode and the cathode (of the carbon dioxide electrolysis unit).
• Carbon dioxide may be reduced to carbon monoxide according to the overall reaction CO2 — CO + 2O2, where at ambient conditions the minimum required cell potential for sustaining carbon dioxide reduction may vary in the range 1.5-3 V dependent on the partial pressures of the gases (CO2, CO, O2), temperature, pH, etc.
• this reaction is the overall reaction which comprises two other equations that are carried out at the cathode and at the anode.
• the reduction of carbon dioxide to carbon monoxide takes place at the cathode, according to the equation: CO2 + 2H + + 2e’ — >CO + H2O, and simultaneously, an oxygen evolution reaction (or “OER”) may take place at the anode according to the equation: H2O — V2O2 + 2H + + 2e'.
• OER oxygen evolution reaction
• oxygen may be produced at the anode of the carbon dioxide electrolysis unit. Especially, the (produced) oxygen may be removed from the carbon comprising stream. Especially, oxygen may be removed prior to the reduction of carbon dioxide to carbon monoxide. In embodiments, oxygen may be selectively removed from the carbon comprising stream by one or more of the following methods: a pressure reduction method, an inert gas purge method, a chemical method, a mechanical degasification method, a membrane degasification method (especially by means of a gas selective membrane permeable to oxygen), or any other suitable method for the removal of oxygen from aqueous streams.
• the anode furnishes H + ions that may acidify an incoming stream. Hence, this may be advantageous in shifting the pH of the medium to acidic, thus resulting in carbon dioxide being the dominant carbonic species.
• the anodic compartment may be configured to accept the carbon comprising stream.
• the carbon comprising stream in embodiments may be an alkaline medium comprising dissolved carbon. This is advantageous since an alkaline medium has a high solubility for carbon dioxide.
• the alkaline medium may be a metal hydroxide of the form MOH, where M may be a metal such as Na, K, Li, Ru, or Cs.
• the carbon comprising stream may be acidified in the anodic compartment.
• the acidified carbon comprising stream may be provided from the anodic compartment and accepted by the cathodic compartment. This is a necessary step, since the reduction of carbon dioxide to carbon monoxide takes place at the cathode.
• the ion-exchange membrane in the carbon dioxide electrolysis unit may be a cation-exchange membrane.
• the cation-exchange membrane is negatively charged and may provide the advantage of containing the carbonic species within the cathodic compartment, thus promoting the reduction of carbon dioxide to carbon monoxide.
• H + is consumed resulting in an abundance of OH' ions, which also leads to basification of the medium in the cathodic compartment.
• chamber may also be referred to as “compartment”.
• the metal ions M + may be reacted with the excess OH' to regenerate the alkaline medium MOH.
• the cathodic compartment may provide the carbon monoxide comprising stream from reduction of carbon dioxide and additionally regenerate the alkaline solution.
• the use of the cation-exchange membrane is essential to regenerating the alkaline solution.
• the regenerated alkaline solution may be reused for the capture of carbon dioxide.
• the conversion of carbon dioxide to carbon monoxide may be the first conversion process.
• the anodic compartment may be configured to accept the carbon comprising stream.
• the (first) carbon comprising stream may be provided to the anodic compartment via the anodic compartment inlet.
• the anodic compartment may comprise an anodic compartment outlet.
• a (second) carbon comprising stream may be provided via the anodic compartment outlet.
• the anodic compartment may comprise a first liquid.
• the first liquid may comprise carbon.
• the first liquid may comprise one or more of carbon dioxide gas (CO2), carbonate ions (CO3 2 ), or bicarbonate ions (HCO3 ).
• the cathodic compartment may be configured to receive the (second) carbon comprising stream, especially via a cathodic compartment inlet.
• the cathodic compartment may comprise a cathodic compartment outlet.
• the alkaline solution may be provided at the cathodic compartment outlet.
• the recirculation stream may be provided at the cathodic compartment outlet.
• the cathodic compartment in addition to the cathodic compartment outlet, the cathodic compartment may comprise a cathodic secondary outlet.
• the carbon monoxide comprising stream may be provided via the cathodic secondary outlet.
• the cathodic compartment may comprise a second liquid.
• the second liquid may comprise carbon.
• the second liquid may comprise one or more of carbon dioxide gas (CO2), carbonate ions (CO3 2 ), or bicarbonate ions (HCO3 ).
• CO2 carbon dioxide gas
• CO3 2 carbonate ions
• HCO3 bicarbonate ions
• the anodic compartment and the cathodic compartment may be separated by the ion-exchange membrane.
• the anodic compartment and the cathodic compartment may be separated by the cation-exchange membrane.
• the first liquid and the second liquid may comprise alkali metal ions M + .
• the ion-exchange membrane (such as the cation exchange membrane) may facilitate the transfer of metal alkali ions M + between the first liquid and the second liquid.
• the ion-exchange membrane of the carbon dioxide electrolysis unit comprises a cation-exchange membrane.
• the cation-exchange membrane may separate the anodic compartment and the cathodic compartment.
• the anodic compartment may be configured between the anode and the ion-exchange membrane.
• the cathodic compartment may be configured between the ion-exchange membrane and the cathode.
• the system may be configured such that, in operation, at least part of the first liquid from the anodic compartment is recirculated to the cathodic compartment. In further embodiments, the system may be configured such that, in operation, at least part of the second liquid from the cathodic compartment is recirculated to the anodic compartment (via a feed input system).
• the stream provided to the anodic compartment may especially be neutral or basic.
• the (first) carbon comprising stream may be provided to the anodic compartment.
• the alkaline solution may be provided to the anodic compartment.
• water may be electrolyzed at the anode of the carbon dioxide electrolysis unit to provide oxygen.
• the electrolysis of water may (also) furnish H + ions.
• the production of H + ions in the anodic compartment may especially acidify the first liquid, thus decreasing the pH of the first liquid.
• the pH of the first liquid in the anodic compartment may be changed from a (neutral) pH of at least 7 to an (acidic) pH of at most 5, such as a pH of at most 4, especially a pH of at most 3.
• the pH of the first liquid in the anodic compartment may be changed from a (basic) pH of at least 9 to an (acidic) pH of at most 5, such as a pH of at most 4, especially a pH of at most 3.
• the pH of the first liquid in the anodic compartment may be changed from a (basic) pH of at least 11 to an (acidic) pH of at most 5, such as a pH of at most 4, especially a pH of at most 3.
• the acidic pH of the anodic compartment may alter the dominant carbon species to aqueous carbon dioxide, thus converting the (first) carbon comprising stream (with CCh 2 ' and HCCh' as the dominant species in the DIC) to the (second) carbon comprising stream (with CC>2(aq) as the dominant species in the DIC).
• the stream exiting the anodic compartment may be acidic.
• the stream exiting the anodic compartment may comprise a pH of at most 5, such as at most 4, especially a pH of at most 3.
• the stream exiting the anodic compartment may comprise the (second) carbon comprising stream.
• the acidic (second) carbon comprising stream may be provided to the cathodic compartment.
• the stream provided to the cathodic compartment may especially be neutral or acidic.
• the (second) carbon comprising stream may be provided to the cathodic compartment.
• water may be electrolyzed at the cathode of the carbon dioxide electrolysis unit to provide hydrogen.
• the electrolysis of water may (also) furnish OH' ions.
• the production of OH' ions in the cathodic compartment may especially turn the second liquid basic, thus increasing the pH of the second liquid.
• the pH of the second liquid in the cathodic compartment may be changed from a (neutral) pH of at most 7 to a (basic) pH of at least 9, such as a pH of at least 10, especially a pH of at least 11.
• the pH of the second liquid in the cathodic compartment may be changed from an (acidic) pH of at most 5 to a (basic) pH of at least 9, such as a pH of at least 10, especially a pH of at least 11.
• the pH of the second liquid in the cathodic compartment may be changed from an (acidic) pH of at most 3 to a (basic) pH of at least 9, such as a pH of at least 10, especially a pH of at least 11.
• the stream exiting the cathodic compartment may be basic. Especially, the stream exiting the cathodic compartment may comprise a pH of at least 9, such as at least 10, especially a pH of at least 11. In further embodiments, the stream exiting the cathodic compartment may comprise the alkaline solution.
• the pH of the first liquid may change from at least 9 to at most 5.
• the pH of the second liquid may change from at most 5 to at least 9.
• the (second) carbon comprising stream provided at the anodic compartment outlet may be provided to the cathodic compartment inlet.
• a recirculation stream may be provided at the cathodic compartment outlet.
• water may be electrolyzed at the cathode.
• the electrolysis of water may provide hydrogen gas and OH' ions.
• the recirculation stream may comprise the (generated) OH'.
• the (generated OH') may especially be used to capture CO2. Therefore, the recirculation stream may facilitate further capture of carbon dioxide.
• the recirculation stream may especially facilitate recirculation of OH' ions, especially the recirculation of OH' within (at least part of) the electrical cell comprising system.
• the capture or the addition of DIC to the recirculation stream may enrich the DIC content in the recirculation stream.
• the recirculation stream may be converted to the (first) carbon stream.
• the recirculation stream may also be referred to as the “remainder stream”.
• the (first) carbon comprising stream may comprise a carbon dioxide content of cl wt.%.
• the (second) carbon comprising stream comprises a carbon dioxide content of c2 wt.%.
• c2 > cl especially in embodiments c2 > cl, such as c2 > 2*cl, especially c2 > 5*cl, even more especially c2 > 10*cl.
• the anodic compartment comprises a first liquid and the cathodic compartment comprises a second liquid, wherein the system is configured such that in operation: at least part of the (first) liquid from the anodic compartment is recirculated to the cathodic compartment; and at least part of the (second) liquid from the cathodic compartment is recirculated to the anodic compartment via a feed input system.
• the system may be configured to execute a second conversion process, comprising electrolyzing water to provide a hydrogen comprising stream.
• the electrolysis of water provides hydrogen and oxygen.
• oxygen may be produced as a byproduct of the second conversion process.
• the system may provide carbon monoxide by executing the first conversion process and the system may provide hydrogen by executing the second conversion process.
• the system may be configured to execute the first conversion process and the second conversion process in the electrical cell comprising system.
• the system may be configured to pressurize one or more of (i) the carbon comprising stream, and (ii) the carbon monoxide comprising stream within at least part of the electrical cell comprising system at a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• the system may comprise pumps that may be configured external or internal to the electrical cell comprising system. Especially for uncompressed systems, gaseous carbon dioxide may settle (as bubbles) on the cathode or on the ion-exchange membrane of the carbon dioxide electrolysis unit (especially when (locally) acidified). This may lead to localized hot spots of high current density. Pressurizing the carbon comprising streams may provide the advantage of preventing the out-gassing of bubbles.
• carbon dioxide remains dissolved due to the applied pressure resulting also in pressurized carbon monoxide, which may provide the advantage of providing a carbon monoxide comprising stream under pressure. Carbon dioxide may remain dissolved at the chosen concentrations for the electrolysis process. Further, the increased pressure may also aid the reaction in achieving near-unit selectivity. In embodiments, carbon monoxide may be separated by phase, collected, and used for subsequent hydrocarbon synthesis.
• the carbon dioxide electrolysis unit may comprise an anode selected from the group of Ni and Ti. In embodiments, the carbon dioxide electrolysis unit may comprise a carbon-based cathode. In further embodiments, the carbon dioxide electrolysis unit may comprise a catalyst selected from the group of an oxide of one or more of Ag, Cu, Au, Zn, Ru and Ir catalyst. In embodiments, the cathode, or the anode, or both may (already) comprise the catalyst. In further embodiments, the anode may comprise catalyst comprising Ru or Ir. In further embodiments, the cathode may comprise catalysts of Ag, Cu, Au, and Zn.
• the system may comprise a feed input system.
• the feed input system may be configured to contact air or flue gas with the alkaline solution to provide the carbon comprising stream.
• the alkaline solution may be recirculated within the system.
• the system comprises a feed input system, wherein the feed input system is configured to contact air or flue gas with the alkaline solution to provide the carbon comprising stream, wherein the alkaline solution is recirculated within the system.
• the alkaline solution may be used by the feed input system to capture carbon dioxide to provide a carbon comprising stream.
• the carbon comprising stream is provided to the electrical cell comprising system.
• the carbon dioxide electrolysis unit comprised by the electrical cell comprising system may be configured to provide the alkaline solution, thus regenerating the alkaline solution.
• the regenerated alkaline solution may be recirculated to the feed input system to facilitate further capture of carbon dioxide. This provides the advantage of reusing the (same) alkaline solution in the system.
• the alkalinity of the alkaline solution provides the advantage of capturing carbon dioxide by exploiting the high solubility of carbon dioxide in alkaline pH.
• Air or flue gas may be a rich source of gaseous carbon dioxide.
• the feed system may facilitate the capture of carbon from these gaseous sources.
• the alkaline solution (or medium) may be used as the capture solvent.
• the feed system may contact the gaseous carbon dioxide with the alkaline solution.
• the carbonic species upon contacting the alkaline solution in embodiments may be dissolved in an aqueous alkaline solution to provide the carbon comprising stream. Carbon dioxide concentration in the air or flue gas may vary. Hence, it may be necessary to increase the amount of captured carbon dioxide.
• the first conversion process recovers the alkaline solution from the carbon comprising stream.
• the alkaline solution may be reused to capture carbon dioxide, thereby increasing the captured carbon content in the system.
• the feed input system may comprise a membrane gas-liquid contactor, such as hollow fiber gas-liquid membrane contactors.
• a gas-liquid contactor provides a wide area of contact between the carbon dioxide blowing into the contactor and the capture solvent i.e. the alkaline solution.
• the feed system may be configured to pressurize the carbon dioxide to a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• the carbon dioxide comprising gas may be introduced into and moved through the feed input system by fans.
• a constant gas flow may be present in the feed input system.
• the carbon dioxide comprising gas may have atmospheric pressure.
• the carbon dioxide comprising gas may be pressurized, such as up to about 2 bar, or higher.
• the feed system may be configured to pressurize the carbon dioxide to a pressure of at maximum 2 bar or the feed system may be configured to operate under atmospheric pressure.
• the pH of the alkaline solution in the feed input system may be at least 7, such as at least 9, especially at least 11.
• the feed input system may comprise an absorber tower. In specific embodiments, the feed input system may comprise a contactor.
• the feed system may be configured to pressurize the alkaline solution and carbon comprising stream to a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• the system may comprise a pressurizer.
• the electrical cell comprising system may comprise a pressurizer.
• the carbon dioxide electrolysis unit may comprise the pressurizer.
• the pressurizer may be configured to pressurize one or more of the alkaline stream, the (first) carbon comprising stream and the (second) carbon comprising stream.
• the stream circulating from the anodic compartment to the cathodic compartment may be pressurized at a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• the stream circulating from the cathodic compartment to the anodic compartment may be pressurized at a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• the feed input system may be configured to receive sea water, and the carbon comprising stream may comprise sea water.
• the feed input system is configured to receive sea water, wherein the carbon comprising stream comprises sea water.
• the electrical cell comprising system may comprise a bipolar membrane electrodialysis unit.
• the bipolar membrane electrodialysis unit may comprise an anode, a cathode and one or more repeating cell units.
• the repeating cell unit may further comprise a combination of a cation-exchange membrane, an anion-exchange membrane, or a bipolar membrane.
• the system may be configured to apply a potential difference selected from the range of 0.6-2V per repeating cell unit, such as especially 1-1.5V per repeating cell unit.
• the system may be configured to provide the carbon comprising stream, and the alkaline solution.
• the electrical cell comprising system comprises a bipolar membrane electrodialysis unit (or “BPMED” unit), wherein the bipolar membrane electrodialysis unit comprises an anode, a cathode, an acidic compartment, a basic compartment and one or more repeating cell units, wherein the repeating cell unit further comprises a combination of a cation-exchange membrane, an anion-exchange membrane, and a bipolar membrane, wherein the bipolar membrane electrodialysis unit is configured to apply a potential difference selected from the range of 0.6-2V per repeating cell unit, wherein the bipolar membrane electrodialysis unit is configured to provide the carbon comprising stream, and the alkaline solution.
• BPMED bipolar membrane electrodialysis unit
• the BPMED may comprise a plurality of repeating cell units.
• the plurality of repeating cell units may be configured between the anode (of the BPMED unit) and the cathode (of the BPMED unit).
• the ion-exchange membranes may divide the BPMED unit into the plurality of repeating cell units.
• the ion-exchange membranes may further divide each repeating cell unit into one or more of the acidic compartment and the basic compartment.
• the one or more ion-exchange membranes divide the repeating cell unit into one or more of the acidic compartment and the basic compartment.
• each repeating cell unit may be adjacent to another repeating cell unit.
• one or more repeating cell units may share an ion-exchange membrane.
• two repeating cells units may share the same ion-exchange membrane. That is, in embodiments, the one or more repeating cell units may be bounded by the same ion-exchange membrane.
• the electrical cell comprising system may comprise a bipolar membrane electrodialysis unit, wherein the bipolar membrane electrodialysis unit comprises an anode, a cathode and one or more repeating cell units, wherein each repeating cell unit comprises a combination of a cation-exchange membrane, an anion-exchange membrane, and a bipolar membrane, which may divide the cell unit into an acidic compartment and a basic compartment.
• an acidic compartment of the bipolar membrane electrodialysis unit may be a compartment on the negatively charged side of the bipolar membrane, wherein the acidic compartment is bordered by a second ion-exchange membrane, wherein the second ion-exchange membrane may comprise an anion-exchange membrane or a cation-exchange membrane.
• a basic compartment of the bipolar membrane electrodialysis unit may be a compartment on the positively charged side of the bipolar membrane, wherein the basic compartment is bordered by a second ion-exchange membrane, wherein the second ion-exchange membrane may comprise an anion-exchange membrane or a cation-exchange membrane.
• the repeating cell unit may comprise the acidic compartment and basic compartment separated by the bipolar membrane.
• the bipolar membrane may especially split water to provide H + and OH' ions.
• the addition of H + ions to the acidic compartment may reduce the pH of the acidic compartment.
• the acidic compartment may comprise a pH of at most 7, such as a pH of at most 5, especially a pH of at most 3.
• the addition of OH' ions to the basic compartment may increase the pH of the basic compartment.
• the basic compartment may comprise a pH of at least 7, such as a pH of at least 9, especially a pH of at least 11.
• the acidic compartment and the basic compartment may be bounded by a combination of either (a) the anion-exchange membrane, or (b) the cation exchange membrane, and the bipolar membrane.
• the BPMED unit may be divided into one or more repeating cell units, wherein the ion exchange membranes may further divide each repeating cell unit into one or more of the acidic compartment and the basic compartment.
• the acidic compartment may be configured upstream of the cathodic compartment.
• the basic compartment may be configured upstream of the anodic compartment.
• the BPMED unit may comprise an acidic compartment inlet and an acidic compartment outlet.
• the carbon comprising stream i.e., the (first) carbon comprising stream
• the acidic compartment inlet may be provided to the acidic compartment via the acidic compartment inlet.
• the acidic pH for example a pH lower than 5
• the acidic pH may alter the dominant carbon species to aqueous carbon dioxide, thus converting the (first) carbon comprising stream (with CCh 2 ' and HCCh' as the dominant species in the DIC) to the (second) carbon comprising stream (with CO2(aq) as the dominant species in the DIC) .
• the cathodic compartment (comprised by the carbon dioxide electrolysis unit) may be configured downstream of the acidic compartment (comprised by the BPMED unit).
• the (second) carbon comprising stream may be provided to the cathodic compartment inlet (comprised by the carbon dioxide electrolysis unit).
• the BPMED unit may comprise a basic compartment inlet and a basic compartment outlet.
• the recirculation stream may be provided to the basic compartment inlet.
• the recirculation stream provided at the cathodic compartment outlet (comprised by the carbon dioxide electrolysis unit) may be provided to the basic compartment inlet (comprised by the BPMED unit).
• the OH' may be added to the recirculation stream in the basic compartment (thus lowering the pH of the recirculation stream). Further, in embodiments, the addition of OH' to the recirculation stream may convert the recirculation stream to the alkaline solution (in the basic compartment).
• the alkaline stream provided at the basic compartment outlet may be provided to the anodic compartment inlet, and subsequently from the anodic compartment outlet to the feed input system for the (further) capture of carbon dioxide.
• the feed input system may convert the alkaline stream to the (first) carbon comprising stream. Further, the (first) carbon comprising stream may be provided to the acidic compartment inlet (thus completing the flow loop).
• the addition of H + ions in the acidic compartment of the BPMED unit may acidify the first carbon comprising stream i.e., the pH of the first carbon comprising stream may be decreased. Further, in embodiments, the change in pH may result in a change in the dominant carbon species from CCh 2 ' and/or HCCfi' to CO2. Thus, in embodiments, the first carbon comprising stream may be converted to the second carbon comprising stream within the acidic compartment.
• the second carbon comprising stream provided at the acidic compartment outlet (to the cathodic compartment inlet) may have a pH of at most 7, such as a pH of at most 5, such as a pH of at most 4, especially a pH of at most 3.
• the addition of OH' ions in the basic compartment of the BPMED unit may increase the pH of the recirculation stream. Further, in embodiments, the concentration of the OH' ions in the recirculation stream may be increased within the basic compartment. Further, in embodiments, in this way, the alkaline solution may be regenerated.
• the alkaline solution provided at the basic compartment outlet (to the anodic compartment inlet) may especially have a pH of at least 7, such as a pH of at least 9, especially a pH of at least 11.
• the stream provided at the cathodic compartment inlet i.e., the (second) carbon comprising stream
• the stream provided at the anodic compartment inlet i.e., the alkaline solution
• the carbon dioxide electrolysis unit may comprise an ion-exchange membrane further comprising a cation exchange membrane, or an anion exchange membrane, or a bipolar membrane.
• the BPMED unit may already control the pH of the one or more streams at the cathodic compartment inlet and the anodic compartment inlet, an anion exchange membrane and a bipolar membrane may also be used (in addition to the cation exchange membrane).
• the choice of ion-exchange membrane may provide the advantage of further controlling the pH of the first liquid and the second liquid. Furthermore, the choice of the ion-exchange membrane may provide the advantage of selectivity in the ion species exchanged between the anodic compartment and the cathodic compartment. This may be particularly advantageous in improving efficiency by altering the system operating parameters in situations wherein a carbon feed to the system may vary in carbon content.
• the carbon feed may comprise one or more of sea water, flue gas, and air. Combinations of carbon feeds may also be used.
• seawater may be provided to the system, and during recirculation, flue gas may be contacted with the alkaline solution.
• the basic compartment may comprise a pH of at least 7, such as a pH of at least 9, especially a pH of at least 11.
• the acidic compartment may comprise a pH of at most 7, such as a pH of at most 5, such as a pH of at most 4, especially a pH of at most 3.
• the alkaline solution may comprise a carbon content of c3 wt.%.
• the recirculation stream may comprise a carbon content of c4 wt.%.
• the system may be configured such that in operation at least part of the liquid from the anodic compartment may be recirculated to the cathodic compartment via the feed input system and the bipolar membrane electrodialysis unit. In embodiments, the system may be configured such that in operation at least part of the liquid from the cathodic compartment may be recirculated to the anodic compartment via the bipolar membrane electrodialysis unit.
• the system is configured such that in operation at least part of the liquid from the anodic compartment is recirculated to the cathodic compartment via the feed input system and the bipolar membrane electrodialysis unit; and at least part of the liquid from the cathodic compartment is recirculated to the anodic compartment via the bipolar membrane electrodialysis unit.
• the carbon comprising stream may be pressurized at a pressure selected from the range of 10-70 bar.
• a recirculation stream is provided to the basic compartment, the recirculation stream may be pressurized at a pressure selected from the range of 10-70 bar.
• the system is configured to provide the carbon comprising steam and the alkaline solution, one or more of the carbon comprising stream and alkaline solution may be pressurized at a pressure selected from the range of 10-70 bar.
• the carbon dioxide electrolysis unit may contain a bipolar membrane, a cation-exchange membrane or an anion-exchange membrane.
• a bipolar membrane in the carbon dioxide electrolysis unit is that the produced alkalinity of the CO2 reduction reaction may be counteracted by the acid produced from the bipolar membrane, which keeps the (local) pH relatively constant, favoring the selectivity and stability of the system.
• the crossover of dissolved inorganic carbon species may be reduced when using a bipolar membrane compared to an anion-exchange membrane.
• the bipolar membrane electrodialysis unit may comprise the anode and the cathode.
• the cathode may comprise a combination of lithium and metals such as nickel, manganese, cobalt, and aluminum.
• anode materials may comprise graphite, platinum, and copper.
• the bipolar membrane electrodialysis unit in embodiments may comprise a container configured with the anode and the cathode on either end of the container. Further, in embodiments the container may be divided into compartments by means of ion-exchange membranes. In further embodiments, streams of solutions may be provided to each of these compartments.
• the ion-exchange membranes may be permeable to certain compounds or ions and hence, may facilitate the transfer of compounds or ions to neighboring compartments.
• the repeating cell units may comprise a combination of a pair or a triplet of membranes.
• the repeating cell unit in embodiments may comprise a combination of membranes selected from a cation-exchange membrane, an anion-exchange membrane and a bipolar membrane.
• a plurality of repeating cell units, each comprising a different combination of membranes may be used.
• the repeating cell unit may comprise in order a cation-exchange membrane, a bipolar membrane, and an anion-exchange membrane.
• the same specific embodiment may (also) comprise a repeating cell unit comprising in order an anion-exchange membrane, a bipolar membrane, and another anion-exchange membrane.
• the bipolar membrane splits water to furnish H + and OH' ions on either side of the membrane.
• a repeating cell unit comprising three membranes, where the bipolar membrane is the central membrane may divide the repeating cell unit into two compartments, an acidic compartment (rich in H + ions) and a basic compartment (rich in OH' ions).
• the bipolar membrane electrodialysis unit may comprise a plurality of repeating cell units (which may comprise different types of repeating cell units) such as 1-40 repeating cell units, such as especially 20-30 repeating cell units.
• the cell units may be selected and arranged between the anode and the cathode in the bipolar membrane electrodialysis unit such that they form an alternating series of acidic compartments and basic compartments.
• a potential difference selected from the range of 0.6-2V, such as especially 1-1.5 V may be applied per repeating cell unit between the anode and the cathode.
• a potential difference in the range 24-80V may be applied across the anode and the cathode of a bipolar membrane electrodialysis unit comprising 40 repeating cell units.
• a larger number of repeating cell units may provide the advantage of scaling the size of the bipolar membrane electrodialysis unit (by increasing the number of repeating cell units). Scaling of the size of the bipolar membrane electrodialysis unit may allow a large volume of the carbon comprising stream to be accommodated in the bipolar membrane electrodialysis unit.
• the application of the potential difference across the anode and the cathode promotes the migration of cations (positively charged chemical groups) and anions (negatively charged chemical groups) to the cathode and the anode, respectively.
• the flow of ions may be restricted by the presence of ion-exchange membranes, hence trapping ions between the membranes (or within compartments) of the repeating cell units.
• the bipolar membrane may furnish protons and hydroxide ions upon application of an electrical field.
• the varying concentration of protons and hydroxide ions in the streams between the membranes of the repeating cell unit may cause a significant change in the pH of the streams entering the compartments of the repeating cell unit.
• the bipolar membrane electrodialysis unit may be configured before the carbon dioxide electrolysis unit, i.e., the carbon comprising stream may first be provided to the bipolar membrane electrodialysis unit before being provided to the carbon dioxide electrolysis unit.
• the carbon comprising stream captured in an alkaline medium in the feed input system
• the acidic compartments of the bipolar membrane electrodialysis unit This may provide the advantage of acidifying the carbon comprising stream.
• the acidified carbon comprising stream in embodiments may then be provided to the cathodic compartment of the carbon dioxide electrolysis unit.
• Acidifying the stream results in carbon dioxide as the dominant carbonic species in the carbon comprising stream, which is advantageous as, in embodiments, carbon dioxide may be reduced to carbon monoxide in the carbon dioxide electrolysis unit.
• the carbon monoxide comprising stream may be provided by the cathodic compartment of the carbon dioxide electrolysis unit, and a remainder stream comprising metal ions may be provided.
• the remainder stream may be directed back to the basic compartment(s) of the bipolar membrane electrodialysis unit.
• the hydroxide ions furnished in the basic compartment of the bipolar membrane electrodialysis unit may be reacted with the alkali metal ions in the remainder stream to regenerate the alkaline solution.
• the regenerated alkaline solution in embodiments, may be routed through the anodic compartment of the carbon dioxide electrolysis unit back to the feed input system.
• the regenerated alkaline solution in embodiments, may be reused to capture carbon dioxide.
• the cation-exchange membrane may comprise negatively charged chemical groups.
• the anion-exchange membrane may comprise positively charged chemical groups.
• the bipolar membrane may comprise positively charged chemical groups and negatively charged chemical groups.
• An ion-exchange membrane is a semi-permeable membrane that transports certain dissolved ions, while blocking other ions or neutral molecules.
• An ion-exchange membrane may comprise organic or inorganic polymer with charged (ionic) side groups, such as ion-exchange resins.
• the anion- exchange membrane may contain fixed cationic groups with predominantly mobile anions. Since anions are the majority species, most of the conductivity is due to anion transport.
• the cation-exchange membrane may contain fixed anionic groups with predominantly mobile cations.
• Bipolar membranes are a special class of ion-exchange membranes comprising a cation-exchange membrane and an anion-exchange membrane, allowing the generation of protons and hydroxide ions via a water dissociation mechanism.
• the cationexchange membrane may be selected from the group of a natural or synthetic zeolite, or a sulfonated coal.
• the anion-exchange membrane may be a solid polymer electrolyte membrane comprising positive ionic groups such as quaternary ammonium (QA) functional groups and mobile negatively charged anions.
• the bipolar membrane may be further comprising a combination of the cation-exchange membrane and the anion-exchange membrane.
• the bipolar membrane may further comprise a water dissociation catalyst layer.
• the water dissociation catalyst may comprise A1 3+ O(OH), or Fe 3+ O(OH).
• the water dissociation catalyst may (also) comprise Al-silicates, or Ni-based catalyst.
• These water dissociation catalyst layers may be configured in embodiments as a part of the bipolar membrane.
• the water dissociation catalyst layer may be configured at the junction of the cation-exchange layer and the anion-exchange layers, which continuously takes in water into the junction and dissociates the feedwater into H + /0H' ion pairs. This may provide the advantage of lowering the energy barrier per HO-H bond. Further, it may provide the advantage of improving energy efficiency and faster acid-base generations. Acid-base generations refers to the acidification and basification of the acidic compartment and basic compartments, respectively.
• the electrical cell comprising system may comprise a water electrolysis unit.
• the water electrolysis unit may comprise an anode and a cathode.
• the water electrolysis unit may be configured to apply a potential difference selected from the range of 1.2-3V, such as especially 1.5-2V across the anode and the cathode.
• the water electrolysis unit may be configured to electrolyze water to provide the hydrogen comprising stream.
• a hydrogen comprising stream may also be required to manufacture hydrocarbon-based chemicals.
• water may be provided to the water electrolysis unit.
• the water electrolysis unit may be configured to apply a potential difference between the anode and the cathode of the water electrolysis unit.
• the hydrogen comprising stream may comprise hydrogen and oxygen, such as at least 40% hydrogen, such as at least 50% hydrogen, such as especially at least 60% hydrogen by volume.
• water may be oxidized at the anode to provide oxygen.
• water may be reduced to provide hydrogen at the cathode.
• oxygen may be extracted as a stream from the water electrolysis unit.
• oxygen may be used in the production of hydrocarbon-based compounds.
• the hydrogen evolved may be directed from the water electrolysis unit to provide the hydrogen comprising stream (in the second conversion process).
• the water electrolysis unit may comprise an anode selected from the group comprising one or more of RuOx-based, or IrOx-based, or RuIrOx-based, or Ni-based materials.
• the water electrolysis unit may comprise a metal-based cathode, wherein the metal is selected from the group comprising one or more of a Pt, Ru, and Ni.
• the water electrolysis unit may comprise a metal-based catalyst, wherein the metal is selected from the group comprising one or more of Ru, Rh, Pd, Ag, Os, Ir, Pt, Ni and Au.
• cathode material may comprise platinum electrodes coated with nickel and carbon.
• the anode material may be nickel, cobalt or iron.
• RuOx-based, IrOx-based, or RuIrOx-based may be deposited on the surface of the electrodes to promote the evolution of hydrogen or oxygen at the cathode and anode, respectively.
• Water has a low autoionization at ambient conditions and thus pure water may be a poor conductor of electricity. Thus, a high potential difference may be required for the electrolysis of pure water. Water electrolysis may require efficient catalysts to speed up the chemical reaction, while also preventing the recombination of hydrogen and oxygen.
• electrolytes may be added to reduce the potential difference required for the electrolysis of water.
• electrolytes may be cations of metals such as Li, Rb, K, Cs, Ba, Sr, Ca, Na and Mg.
• strong acids such as sulfuric acid and strong bases such as potassium hydroxide or sodium hydroxide may be added as electrolytes.
• an ion-exchange membrane such as a solid polymer electrolyte may be used.
• a Nafion membrane may effectively split water molecules on either side of the membrane at a potential difference of 1.4-1.6V.
• RuOx-based, IrOx-based, and RuIrOx refer to ruthenium oxide, iridium oxide, and ruthenium iridium oxide, respectively.
• the system may comprise a hydrocarbon synthesis unit.
• the hydrocarbon synthesis unit may be a methanol synthesis unit.
• the methanol synthesis unit may be configured to pressurize the carbon monoxide comprising stream and the hydrogen comprising stream to a pressure selected from the range of 50-100 bar, such as especially 60-80 bar.
• the methanol synthesis unit may be configured to heat a mixture of the carbon monoxide comprising stream and the hydrogen comprising stream to a temperature selected from the range of 250-300°C.
• Methanol synthesis may be a carbon monoxide hydrogenation reaction.
• methanol may be produced with high selectivity.
• the synthesis may be carried out at 250-300 °C.
• the synthesis may be carried out at a pressure selected from the range of 50-100 bar, such as especially 60-80 bar.
• the methanol synthesis unit may use copper-based catalysts for methanol synthesis.
• the dominant catalyst formulation for methanol synthesis may be Cu/ZnO and some alumina that act as structural promoter.
• the composition of the synthesis gas employed for methanol synthesis may contain hydrogen to carbon monoxide in the ratio larger than 2. This provides the advantage of conversion of trace amounts of carbon dioxide in the syngas. Further, this may provide the advantage of suppressing side reactions.
• the hydrocarbon synthesis unit may be configured to produce one or more, such as a range of, hydrocarbons according to the Fischer-Tropsch process.
• the Fischer-Tropsch process is well known in the art and may refer to a collection of chemical reactions that convert a mixture of carbon monoxide and hydrogen into hydrocarbons.
• the hydrocarbon synthesis unit may be configured to produce alkanes according to the reaction: (2n+l)H2 + nCO — C n H2n+2 + nFFO.
• the hydrocarbon synthesis unit may comprise a Fischer-Tropsch process reactor.
• the invention may be a method for providing carbon monoxide and hydrogen using the system.
• the method may comprise applying a potential difference selected from the range of 1-4V, such as especially 1.5-3V across the anode and the cathode of a carbon dioxide electrolysis unit.
• the method may comprise converting in a first conversion process a carbon comprising stream to provide: (i) a carbon monoxide comprising stream, and (ii) an alkaline solution.
• the carbon comprising stream may comprise one or more of carbon dioxide gas, carbonate ions, and bicarbonate ions in an aqueous solution.
• the method may comprise electrolyzing water in a second conversion process to provide a hydrogen comprising stream.
• the method may comprise executing the first conversion process and the second conversion process in an electrical cell comprising system.
• the method may comprise pressurizing one or more of (i) the carbon comprising stream, and (ii) the carbon monoxide comprising stream within at least part of the electrical cell comprising system at a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• the invention may be a method for providing carbon monoxide and (optionally) hydrogen.
• the method may be executed to provide (only) carbon monoxide.
• the method may comprise executing (only) the first conversion process in the electrical cell comprising system (thus providing carbon monoxide).
• the invention may be a method to provide carbon monoxide and hydrogen.
• the method may comprise executing the first conversion process and the second conversion process in the electrical cell comprising system (thus providing carbon monoxide and hydrogen). More especially, the method may comprise executing the first conversion process independent of the second conversion process, and vice versa.
• the invention may be a method to provide carbon monoxide independent of the production of hydrogen.
• the method may (also) comprise electrolyzing water to provide a hydrogen comprising stream (see further below).
• the invention may be a method to provide carbon monoxide and (optionally) hydrogen.
• the invention may be a method for providing carbon monoxide using the system.
• the method may comprise applying a potential difference selected from the range of 1-4V, such as especially 1.5-3V across the anode and the cathode of a carbon dioxide electrolysis unit.
• the method may comprise converting in a first conversion process a carbon comprising stream to provide: (i) a carbon monoxide comprising stream, and (ii) an alkaline solution.
• the carbon comprising stream may comprise one or more of carbon dioxide gas, carbonate ions, and bicarbonate ions in an aqueous solution.
• the method may comprise executing the first conversion process in an electrical cell comprising system.
• the invention may be a method for providing carbon monoxide using the system; comprising applying a potential difference selected from the range of 1.5-3 V across the anode and the cathode of the carbon dioxide electrolysis unit; comprising converting in a first conversion process a carbon comprising stream to provide: (i) a carbon monoxide comprising stream, and (ii) an alkaline solution; wherein the carbon comprising stream comprises one or more of carbon dioxide gas, carbonate ions, and bicarbonate ions in an aqueous solution; comprising executing the first conversion process in the electrical cell comprising system; and comprising pressurizing one or more of (i) the carbon comprising stream, and (ii) the carbon monoxide comprising stream within at least part of the electrical cell comprising system at a pressure selected from the range of 10-70 bar.
• the method may comprise applying a potential difference selected from the range of 1.5-3V across the anode and the cathode of the carbon dioxide electrolysis unit.
• converting in a first conversion process a carbon comprising stream to provide: (i) a carbon monoxide comprising stream, and (ii) an alkaline solution.
• electrolyzing water in a second conversion process to provide a hydrogen comprising stream.
• the method may comprise applying a potential difference selected from the range of 1.5-3V across the anode and the cathode (of the carbon dioxide electrolysis unit).
• the method may comprise reducing carbon dioxide to carbon monoxide at the cathode, according to the equation: CO2 + 2H + + 2e’ — >CO + H2O, and simultaneously, executing an oxygen evolution reaction (or “OER”) at the anode according to the equation: H2O — 2O2 + 2H + + 2e'.
• OER oxygen evolution reaction
• the method may comprise acidifying the carbon comprising stream in the anodic compartment and providing the acidified carbon comprising stream at the anodic compartment and accepting said strain at the cathodic compartment.
• the method may comprise recombining the metal ions M + with the excess OH' to regenerate the alkaline medium MOH (such as comprising NaOH or KOH).
• the method may comprise reducing carbon dioxide to carbon monoxide at the cathodic compartment and additionally regenerating the alkaline solution.
• method may comprise reusing the regenerated alkaline solution for the capture of carbon dioxide.
• the method may comprise converting carbon dioxide to carbon monoxide in a first conversion process.
• the method may comprise executing a second conversion process, comprising electrolyzing water to provide a hydrogen comprising stream.
• the method may comprise providing carbon monoxide by executing the first conversion process and providing hydrogen in the second conversion process.
• the method may comprise executing the first conversion process and the second conversion process in the electrical cell comprising system.
• the method may comprise pressurizing one or more of (i) the carbon comprising stream, and (ii) the carbon monoxide comprising stream within at least part of the electrical cell comprising system at a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• the method may comprise pressurizing the alkaline solution at a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• the method may comprise recirculating at least part of the first liquid from the anodic compartment to the cathodic compartment. In embodiments, the method may comprise recirculating at least part of the second liquid from the cathodic compartment to the anodic compartment. In embodiments, the method may comprise pressurizing the first liquid recirculating from the anodic compartment to the cathodic compartment at a pressure selected from the range of 10-70 bar, such as 30-50 bar. In embodiments, the method may comprise pressurizing the second liquid recirculating from the cathodic compartment to the anodic compartment at a pressure selected from the range of 10-70 bar, such as 30-50 bar.
• the invention may provide a method to provide carbon monoxide and (optionally) hydrogen.
• the method may comprise contacting air or flue gas with the alkaline solution to provide the carbon comprising stream, comprising recirculating the alkaline solution within the system.
• the method may comprise configuring the feed input system to receive sea water, and wherein sea water comprises the carbon comprising stream.
• the method may comprise recirculating at least part of a first liquid from the anodic compartment to the cathodic compartment and recirculating at least part of a second liquid from the cathodic compartment to the anodic compartment (via the feed input system).
• the method may comprise applying a potential difference selected from the range of 0.6-2V, such as especially 1-1.5V per repeating cell unit in a bipolar membrane electrodialysis unit.
• the method may comprise providing the carbon comprising stream, and the alkaline solution.
• the method may comprise providing streams of solutions to each acidic compartment and basic compartment in the bipolar membrane electrodialysis unit.
• the method may comprise applying a potential difference selected from the range of 0.6-2V per repeating cell unit between the anode and the cathode.
• the method may comprise applying a potential difference in the range 24-80V across the anode and the cathode of a bipolar membrane electrodialysis unit comprising 40 repeating cell units.
• the method may comprise configuring the bipolar membrane electrodialysis unit before the carbon dioxide electrolysis unit, i.e., the carbon comprising stream is first provided to the bipolar membrane electrodialysis unit before being provided to the carbon dioxide electrolysis unit.
• the method may comprise providing the carbon comprising stream captured in an alkaline medium (in the feed input system) to the acidic compartments of the bipolar membrane electrodialysis unit.
• the method may comprise providing the acidified carbon comprising stream to the cathodic compartment of the carbon dioxide electrolysis unit.
• the method may further comprise providing the carbon dioxide comprising stream to the cathodic compartment of the carbon dioxide electrolysis unit, and providing a remainder stream comprising metal ions.
• the method may comprise directing the remainder stream back to the basic compartments of the bipolar membrane electrodialysis unit.
• the method may comprise regenerating the alkaline solution by recombining the hydroxide ions furnished in the basic compartment of the bipolar membrane electrodialysis unit with the alkali metal ions in the remainder stream.
• the method may further comprise routing the regenerated alkaline solution through the anodic compartment of the carbon dioxide electrolysis unit back to the feed input system.
• the method may comprise reusing the alkaline solution to capture carbon dioxide.
• the invention may provide a method of providing carbon monoxide and (optionally) hydrogen, especially by means of a BPMED unit.
• the method may comprise applying a potential difference selected from the range of 0.6-2V per repeating cell unit in a bipolar membrane electrodialysis unit, the method comprising providing the carbon comprising stream, and the alkaline solution.
• the method may comprise increasing the pH within the basic compartment to at least 9 and lowering the pH in the acidic compartment to at most 5. More especially, the method may comprise flowing a liquid from the acidic compartment to the cathodic compartment, wherein the acidic compartment is configured upstream of the cathodic compartment and flowing a liquid from the basic compartment to the anodic compartment, wherein the basic compartment is configured upstream of the anodic compartment.
• the method may comprise recirculating at least part of the first liquid from the anodic compartment to the cathodic compartment via the feed input system and the bipolar membrane electrodialysis unit and recirculating at least part of the second liquid from the cathodic compartment to the anodic compartment via the bipolar membrane electrodialysis unit.
• the method may comprise applying a potential difference selected from the range of 1.2-3V across the anode and the cathode of a water electrolysis unit, wherein the water electrolysis unit comprises an anode and a cathode; the method comprising electrolyzing water in the water electrolysis unit to provide the hydrogen comprising stream.
• the method may comprise pressurizing one or more of the carbon comprising stream (especially the (first) carbon comprising stream and the (second) carbon comprising stream), recirculation stream, and alkaline solution within at least part of the system at a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• the method may comprise recirculation of at least part of the first liquid from the anodic compartment of the carbon dioxide electrolysis unit to the cathodic compartment of the carbon dioxide electrolysis unit via the feed input system and the bipolar membrane electrodialysis unit. Further, in embodiments, the method may comprise recirculation of at least part of the second liquid from the cathodic compartment of the carbon dioxide electrolysis unit to the anodic compartment of the carbon dioxide electrolysis unit via the bipolar membrane electrodialysis unit.
• the method may comprise executing a second conversion process, comprising electrolyzing water to provide a hydrogen comprising stream.
• the method may comprise providing hydrogen by executing the second conversion process.
• the method may comprise executing the second conversion process in the electrical cell comprising system.
• the method may comprise converting the carbon monoxide comprising stream and the hydrogen comprising stream to provide a methanol comprising stream at a pressure of 50-100 bar and 250-300°C.
• the carbon monoxide (comprised by the carbon monoxide comprising stream) and the hydrogen (comprised by the hydrogen comprising stream) are provided in 1 :2 volume ratio to the methanol synthesis unit.
• Methanol may be synthesized in a two-step process. The first step of the process may involve providing a mixture of high-pressure carbon monoxide and hydrogen in the ratio of 1 :2 by volume to produce synthesis gas. In the second step, synthesis gas may be converted to methanol at a temperature of 250-300 °C and a pressure of 50-100 bar.
• the method may comprise using catalysts selected from the group comprising one or more of Cu, ZnO, and AI2O3.
• the method may comprise reacting carbon monoxide with hydrogen according to the equation: CO + 2H2 — CH3OH.
• additional reactions may also take place in the methanol synthesis unit, such as (i) unreacted carbon dioxide in the carbon monoxide comprising stream may react with hydrogen (CO2 + 3H2 — CH3OH + H2O) to produce methanol and water, and (ii) carbon monoxide in the carbon monoxide comprising stream may react with water (CO + H2O — CO2 + H2).
• the methanol comprising stream may comprise methanol, steam, carbon dioxide, carbon monoxide, and hydrogen.
• methanol may be produced with high selectivity, where the methanol comprising stream may comprise at least 55% methanol, such as at least 65% methanol, such as at least 75% methanol.
• the invention provides a system to capture carbon dioxide in an aqueous solution. Further, the invention provides a system to capture carbon dioxide in an aqueous solution and convert the carbon dioxide. Further, the present invention provides a method to capture carbon dioxide in an aqueous solution and convert the carbon dioxide electrochemically.
• Fig. 1 schematically depicts an embodiment of the system 1000 to provide carbon monoxide and hydrogen
• Fig. 2 schematically depicts an embodiment of the system 1000 comprising a bipolar membrane electrodialysis unit 410 configured in the electrical cell comprising system 2000
• Fig. 3 schematically depicts an embodiment of the system 1000 to provide carbon monoxide and (optionally) hydrogen
• Fig. 4 schematically depicts an embodiment of the system 1000 comprising a bipolar membrane electrodialysis unit 410 configured in the electrical cell comprising system 2000.
• the schematic drawings are not necessarily to scale.
• Fig. 1 schematically depicts an embodiment of the system 1000.
• the system may provide carbon monoxide and hydrogen.
• the system 1000 may comprise an electrical cell comprising system 2000.
• the electrical cell comprising system 2000 may comprise a carbon dioxide electrolysis unit 430.
• the carbon dioxide electrolysis unit 430 may comprise an anode 431, a cathode 432, and an ion-exchange membrane 416 further comprising a cation-exchange membrane 413, or an anion-exchange 414 membrane, or a bipolar membrane 415.
• the carbon dioxide electrolysis unit 430 may be configured to apply a potential difference selected from the range of 1.5-3 V across the anode 431 and the cathode 432.
• the system 1000 may be configured to pressurize one or more of (i) the carbon comprising stream 210, 220, and (ii) the carbon monoxide comprising stream 230 within at least part of the electrical cell comprising system 2000 at a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• the invention provides a system 1000 for providing carbon monoxide.
• the system 1000 may comprise an electrical cell comprising system 2000.
• the electrical cell comprising system 2000 may comprise a carbon dioxide electrolysis unit 430.
• the carbon dioxide electrolysis unit 430 may comprise an anode 431, a cathode 432, an anodic compartment 4311, a cathodic compartment 4321 and an ion-exchange membrane 416.
• the ion exchange membrane 416 may further comprise a cation-exchange membrane 413, or an anion-exchange membrane 414, or a bipolar membrane 415.
• the carbon dioxide electrolysis unit 430 may be configured to apply a potential difference selected from the range of 1.5-3 V across the anode 431 and the cathode 432.
• the system 1000 may be configured to convert in a first conversion process a carbon comprising stream 210, 220 to provide: (i) a carbon monoxide comprising stream 230, and (ii) an alkaline solution 240. Especially, the system 1000 may be configured to execute the first conversion process in the electrical cell comprising system 2000.
• the carbon comprising stream 210, 220 i.e. the (first) carbon comprising stream 210 and the (second) carbon comprising stream 220
• a carbon comprising stream 210 may be provided to the anodic compartment 4311 of the carbon dioxide electrolysis unit 430 (especially, the (first) carbon comprising stream 210 may be provided to the anodic compartment 4311 via the anodic compartment inlet 4318). Furthermore, in embodiments, the carbon comprising stream 220 may be provided to the cathodic compartment 4321 of the carbon dioxide electrolysis unit 430 (especially, the (second) carbon comprising stream 220 may be provided to the cathodic compartment 4321 via the cathodic compartment inlet 4328).
• system 1000 may be configured to pressurize one or more of (i) the carbon comprising stream 210, 220, and (ii) the carbon monoxide comprising stream 230 within at least part of the electrical cell comprising system 2000 at a pressure selected from the range of 10-70 bar.
• system 1000 may be configured to pressurize the alkaline solution 240 within at least part of system 1000 at a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• the carbon comprising stream 210 may be provided to the anodic compartment 4311.
• the carbon comprising stream 210 is acidified in the anodic compartment 4311.
• the acidified carbon comprising stream 220 may be provided by the cathodic compartment 4321.
• the carbon comprising stream 220 may be provided to the cathodic compartment 4321 (via the cathodic compartment inlet 4328).
• the acidified carbon comprising stream 220 may be converted in a first conversion process to provide: (i) a carbon monoxide comprising stream 230, and (ii) an alkaline solution 240.
• protons may be consumed during the first conversion process.
• the consumption of protons may increase the pH in the cathodic compartment to at least 7, such as at least 9, such as at least 11.
• the (second) liquid comprised by the cathodic compartment may be basic, and may comprise the alkaline solution 240.
• the alkaline solution 240 may be provided to the feed input system 100 (especially, the alkaline solution may be provided to the feed input system 100 via the cathodic compartment outlet 4329).
• the alkaline solution 240 may be used to capture carbon dioxide in the feed input system 100.
• the feed input system 100 may provide the (first) carbon comprising stream 210.
• the system 1000 may be configured such that in operation at least part of the first liquid from the anodic compartment 4311 is recirculated to the cathodic compartment 4321. Further, in embodiments, the system 1000 may be configured such that in operation at least part of the second liquid from the cathodic compartment 4321 is recirculated to the anodic compartment 4311.
• the ion-exchange membrane 416 of the carbon dioxide electrolysis unit 430 may comprise a cation-exchange membrane 413.
• the anodic compartment 4311 may be the compartment between the anode 431 and the ion-exchange membrane 416.
• the cathodic compartment 4321 may be the compartment between the ion-exchange membrane 416 and the cathode 432.
• the system 1000 may comprise a feed input system 100.
• the feed input system 100 may be configured to contact air or flue gas with the alkaline solution 240 to provide the carbon comprising stream 210.
• the alkaline solution 240 may be recirculated within the system 1000.
• the feed input system 100 may be configured to receive sea water, and wherein the carbon comprising stream 210 may comprise the sea water.
• a carbon feed 101 may be provided to the feed input system 100.
• the carbon feed 101 may comprise sea water.
• the carbon feed 101 may be (directly) added to the alkaline solution 240 in the feed input system 100.
• the carbon feed 101 may comprise air or flue gas.
• the carbon feed 101 may be blown by means of fans to expose the alkaline solution 240 in the feed input system 100.
• the cation-exchange membrane 413 may comprise negatively charged chemical groups, wherein the anion-exchange membrane 414 may comprise positively charged chemical groups, wherein the bipolar membrane 415 may comprise positively charged chemical groups and negatively charged chemical groups.
• the cation-exchange membrane 413 may be selected from the group of a natural or synthetic zeolite, or a sulfonated coal; wherein the anion-exchange membrane 414 may comprise a solid polymer electrolyte membrane comprising positive ionic groups, selected from quaternary ammonium (QA) functional groups and mobile negatively charged anions, and wherein the bipolar membrane 415 may further comprise a combination of the cation-exchange membrane 413 and the anion-exchange membrane 414.
• QA quaternary ammonium
• the electrical cell comprising system 2000 may comprise a water electrolysis unit 420.
• the water electrolysis unit 420 may comprise an anode 421 and a cathode 422.
• the water electrolysis unit 420 may be configured to apply a potential difference selected from the range of 1.2-3V, such as especially 1.5-2V across the anode 421 and the cathode 422.
• the water electrolysis unit 420 may be configured to electrolyze water to provide the hydrogen comprising stream 250.
• the water electrolysis unit 420 may comprise an anode selected from the group comprising one or more of RuOx-based, or IrOx-based, or RuIrOx- based, or Ni-based materials.
• the water electrolysis unit 420 may comprise a metal-based cathode, wherein the metal is selected from the group comprising one or more of a Pt, Ru, and Ni.
• the water electrolysis unit 420 may comprise a metal-based catalyst, wherein the metal is selected from the group comprising one or more of Ru, Rh, Pd, Ag, Os, Ir, Pt, Ni and Au.
• the carbon dioxide electrolysis unit 430 may comprise an anode selected from the group of Ni or Ti, a carbon based cathode, and a catalyst selected from the group of an oxide of one or more of Ag, Cu, Au, Ru and Ir catalyst.
• the cathode, or the anode, or both may (already) comprise the catalyst.
• the anode may comprise catalyst comprising Ru or Ir.
• the cathode may comprise catalysts of Ag, Cu, Au, and Zn.
• the system may comprise a methanol synthesis unit 440.
• the methanol synthesis unit 440 may be configured to pressurize a mixture of the carbon monoxide comprising stream 230 and the hydrogen comprising stream 250 to a pressure selected from the range of 50-100 bar, heat the mixture of the carbon monoxide comprising stream 230 and the hydrogen comprising stream 250 to a temperature selected from the range of 250-300°C.
• the invention may be a method for providing a carbon monoxide and a hydrogen comprising stream using the system.
• the method may comprise applying a potential difference selected from the range of 1.5-3 V across the anode 431 and the cathode 432 of the carbon dioxide electrolysis unit 430.
• the method may comprise converting in a first conversion process a carbon comprising stream 210, 220 to provide: (i) a carbon monoxide comprising stream 230, and (ii) an alkaline solution 240; wherein the carbon comprising stream 210, 220 comprises one or more of carbon dioxide gas, carbonate ions, and bicarbonate ions in an aqueous solution.
• the method may comprise electrolyzing water in a second conversion process to provide a hydrogen comprising stream 250.
• the method may comprise executing the first conversion process and the second conversion process in the electrical cell comprising system 2000.
• the method may comprise pressurizing one or more of (i) the carbon comprising stream 210, and (ii) the carbon monoxide comprising stream 230 within at least part of the electrical cell comprising system 2000 at a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• the method may comprise converting the carbon monoxide comprising stream 230 and the hydrogen comprising stream 250 to provide a methanol comprising stream 260 at a pressure of 50-100 bar and 250-300°C.
• the method may comprise recirculating part of the first liquid from the anodic compartment 4311 to the cathodic compartment 4321. In embodiments, the method may comprise recirculating part of the second liquid from the cathodic compartment 4321 to the anodic compartment 4311, especially via the feed input system 100.
• the system may take one of two flow paths depending on the embodiment of the system.
• the first flow path may involve the capture of carbon dioxide from a carbon source such as air, flue gas or seawater using the feed input system 100.
• the feed input system 100 may use blowers to contact carbon dioxide with an alkaline solution 240.
• the carbon dioxide may be dissolved in the alkaline solution and may exist as carbonate ions or bicarbonate ions to provide the carbon comprising stream 210.
• the carbon comprising stream 210 may be provided to the anodic compartment of the carbon dioxide electrolysis unit 430.
• water may be oxidized to produce an oxygen stream 280.
• the oxygen stream 280 may be separated and used in a later stage of the process.
• the remainder comprises an alkaline medium comprising carbonate ions and bicarbonate ions.
• the stream exiting at the anodic compartment may be a slightly acidic to neutral stream comprising carbon i.e. the carbon comprising stream 220.
• the change in the pH of the stream may result in a change in the dominant carbonic species.
• the decrease in pH may result in carbon out-gassing as dissolved carbon dioxide in the carbon comprising stream 220.
• the carbon comprising stream may be provided to the cathodic chamber of the carbon dioxide electrolysis unit 430.
• the dissolved pressurized carbon dioxide may be reduced at the cathode 432 to provide a pressurized carbon monoxide comprising stream 230. Further, there may be migration of cations such as Na + and K + across the cation-exchange membrane 413 i.e. transport of ions from the anodic chamber to the cathodic chamber. Further, the cathode 432 may furnish hydroxide ions. The cations may react with the hydroxide ions to regenerate the alkaline solution 240. In embodiments, the alkaline solution 240 may be recirculated to the feed input system 100, for further carbon capture.
• cations such as Na + and K + across the cation-exchange membrane 413 i.e. transport of ions from the anodic chamber to the cathodic chamber.
• the cathode 432 may furnish hydroxide ions. The cations may react with the hydroxide ions to regenerate the alkaline solution 240. In embodiments, the alkaline solution
• Fig. 2 schematically depicts an embodiment of the system 1000 comprising a bipolar membrane electrodialysis unit 410 configured in the electrical cell comprising system 2000.
• the invention may be a system 1000 for providing carbon monoxide and hydrogen.
• the system 1000 may comprise an electrical cell comprising system 2000 further comprising a carbon dioxide electrolysis unit 430.
• the system 1000 may be configured to convert in a first conversion process a carbon comprising stream 210, 220 to provide: (i) a carbon monoxide comprising stream 230, and (ii) an alkaline solution 240.
• the system 1000 may be configured to electrolyze water in a second conversion process to provide a hydrogen comprising stream 250.
• the system 1000 may be configured to execute the first conversion process and the second conversion process in the electrical cell comprising system 2000.
• the electrical cell comprising system 2000 may comprise a bipolar membrane electrodialysis unit 410.
• the bipolar membrane electrodialysis unit 410 may comprise an anode 411, a cathode 412 and one or more repeating cell units 4110.
• each repeating cell unit 4110 may further comprise a combination of a cationexchange membrane 413, an anion-exchange membrane 414, and a bipolar membrane 415.
• the repeating cell unit 4110 may further comprise a combination of a cation-exchange membrane 413, an anion-exchange membrane 414, a bipolar membrane 415, an acidic compartment 531 and a basic compartment 532.
• the carbon comprising stream 210 may be provided to the acidic compartment 531.
• a recirculation stream 270 may be provided to the basic compartment 532.
• an acidic compartment 531 of the bipolar membrane electrodialysis unit 410 may be a compartment on the negatively charged side of the bipolar membrane 415, wherein the acidic compartment 531 is bordered by a second ion-exchange membrane, wherein the second ion-exchange membrane may comprise an anion-exchange membrane 414 or a cation-exchange membrane 413.
• a basic compartment 532 of the bipolar membrane electrodialysis unit 410 may be a compartment on the positively charged side of the bipolar membrane 415, wherein the basic compartment 532 is bordered by a second Ion-exchange membrane, wherein the second ion-exchange membrane may comprise an anion-exchange membrane 414 or a cation-exchange membrane 413.
• the bipolar membrane electrodialysis unit 410 may be configured to apply a potential difference selected from the range of 0.6-2V, such as especially 1-1.5V per repeating cell unit 4110. Further, in embodiments the bipolar membrane electrodialysis unit 410 may be configured to provide the carbon comprising stream 220, and the alkaline solution 240. In embodiments, the bipolar membrane electrodialysis unit 410 may further comprise a water dissociation catalyst layer, wherein the water dissociation catalyst comprises Al 3+ 0(0H), or Fe 3+ O(OH), or Al-silicates, or Ni-based catalyst. In embodiments, the electrical cell comprising system 2000 may comprise a water electrolysis unit 420.
• the streams comprised in the system may be configured to take a second flow path.
• carbon dioxide may be captured from a source such as air, flue gas or seawater using the feed input system 100.
• the feed input system 100 may use blowers to dissolve carbon dioxide in the alkaline solution 240 such as KOH and NaOH, which may act as the capture solvent.
• the alkaline nature of the capture solvent may allow the capture of carbon dioxide in the form of carbonate ions and bicarbonate ions. Further, these ions may be captured in the alkaline solution as metallic carbonates and metallic bicarbonates such as K2CO3, Na2COs, KHCO3, and NaHCCF.
• the alkaline medium (or solution) 240 with the dissolved ions may be the carbon comprising stream 210.
• the carbon comprising stream 210 may be pressurized to a pressure selected from the range of 10- 70 bar, such as specifically 30-50 bar.
• sea water comprising dissolved carbon may be used as the carbon comprising stream.
• the bipolar membrane electrodialysis unit 410 may comprise a number of repeating cell units 4110 further comprising a cation-exchange membrane 413, an anion-exchange membrane 414 and a bipolar membrane 415.
• the repeating cell units 4110 in embodiments, may comprise acidic compartment 531 and basic compartments 532.
• the carbon comprising stream 210 may be provided to the acidic compartment 531 which may be contained between a positively charged anion-exchange membrane 414 and a bipolar membrane 415.
• the basic compartment 532 may be between the cation-exchange membrane 413 and the bipolar membrane 415.
• the carbon comprising stream 220 may be rich in carbon dioxide (and carbonic acid), due to the acidic nature of the stream in the acidic compartment 531.
• the carbon comprising stream(s) 210, 220 may be pressurized and hence, the carbon dioxide may remain dissolved in the acidic stream.
• the carbon comprising stream 220 may be provided to the cathodic compartment of the carbon dioxide electrolysis unit 430.
• the dissolved carbon dioxide in embodiments, may be reduced electrochemically at the cathode 432 of the carbon dioxide electrolysis unit 430 to provide a high-pressure gaseous carbon monoxide comprising stream 230.
• the carbon monoxide comprising stream 230 may be extracted from the cathodic compartment.
• the (remainder) carbon comprising stream 220 may be provided back to the bipolar membrane electrodialysis unit 410.
• the (remainder) carbon comprising stream may be a stream that may especially be deficit in carbon content since carbon dioxide may be electrolytically reduced at the cathode of the carbon dioxide electrolysis unit.
• the (remainder) carbon comprising stream may be referred to herein as the recirculation stream 270.
• the recirculation stream 270 may comprise (at least a finite amount of) DIC and hence in some instances referred to as the (remainder) carbon comprising stream.
• this stream in embodiments, may be provided to the basic compartment(s) 532 of the bipolar membrane electrodialysis unit 410.
• the cations i.e. alkali metal ions such as Na + and K + may be reacted with the hydroxide ions furnished by the bipolar membrane(s) 415 to regenerate the alkaline solution 240.
• the alkaline solution 240 may be provided to the anodic compartment of the carbon dioxide electrolysis unit 430.
• water may be oxidized to produce a gaseous oxygen stream 280.
• the gaseous oxygen stream 280 may be separated and used in a later stage of the process.
• the alkaline solution 240 (exiting from the anodic compartment) may be recirculated to the feed input system 100 to capture carbon from the carbon source.
• the pressurized carbon monoxide comprising stream 230 may be used in the production of methanol in the subsequent methanol synthesis step.
• system 1000 may be configured to pressurize the alkaline solution 240 within at least part of system 1000 at a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• gaseous carbon monoxide stream 230 may be pressurized in at least part of the system 1000.
• system 1000 may be configured such that the acidic compartment 531 is configured upstream of the cathodic compartment 4321. Further, in embodiment, the system 1000 may be configured such that the basic compartment 532 is configured upstream of the anodic compartment 4311.
• the system 1000 may be configured such that in operation at least part of the first liquid from the anodic compartment 4311 is recirculated to the cathodic compartment 4321 via the feed input system 100 and the bipolar membrane electrodialysis unit 410. Further, in embodiments, the system 1000 may be configured such that in operation at least part of the second liquid from the cathodic compartment 4321 is recirculated to the anodic compartment 4311 via the bipolar membrane electrodialysis unit 410.
• the ion-exchange membrane 416 in the carbon dioxide electrolysis unit 430 is negatively charged.
• this membrane may also be positively charged.
• this membrane may comprise a bipolar membrane 415, and may thus have both negative and positive charges.
• a parallel process for the generation of the hydrogen comprising stream 250 may be executed in the water electrolysis unit 420. In embodiments, this may also be carried out under pressure selected from the range of 50-100 bar, such as especially 60-80 bar.
• the electrolysis of water may provide the pressurized hydrogen comprising stream 250 which may be necessary for the providing a methanol comprising stream 260 in the methanol synthesis unit 440.
• both the carbon monoxide comprising stream 230 and the hydrogen comprising stream 250 may be further pressurized to a pressure selected from the range of 50-100 bar.
• the carbon monoxide comprising stream 230 and the hydrogen comprising stream 250 may be heated to a temperature selected from the range of 250 - 300 °C. In embodiments, they may be combined in a 1 :2 ratio of carbon monoxide to hydrogen to form synthesis gas. Synthesis gas may be used to produce methanol in standard methanol synthesis process. In embodiments, the methanol synthesis unit 440 may use a copper-zinc based catalyst.
• the carbon dioxide electrolysis unit 430 may be configured to apply a potential difference selected from the range of 1.5-3V across the anode 431 and the cathode 432.
• the system 1000 may be configured to convert in a first conversion process a carbon comprising stream 210, 220 to provide: (i) a carbon monoxide comprising stream 230, and (ii) an alkaline solution 240.
• the carbon comprising stream 210, 220 may comprise one or more of carbon dioxide, carbonate ions, and bicarbonate ions in an aqueous solution.
• the system 1000 may be configured to execute the first conversion process in the electrical cell comprising system 2000.
• the system 1000 may be configured to pressurize one or more of (i) the carbon comprising stream 210, 220, and (ii) the carbon monoxide comprising stream 230 within at least part of the electrical cell comprising system 2000 at a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• the system 1000 may be configured to pressurize the alkaline solution 240 within at least part of the system 1000 at a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• the system 1000 according to any one of the preceding claims, may comprise a feed input system 100.
• the feed input system 100 may be configured to contact air or flue gas with the alkaline solution 240 to provide the carbon comprising stream 210.
• the alkaline solution 240 may be recirculated within the system 1000.
• the carbon dioxide comprising gas may be blown through the feed input system 100 by fans.
• the carbon dioxide comprising gas may (only) be pressurized to atmospheric pressure.
• the anodic compartment 4311 may be the compartment between the anode 431 and the ion-exchange membrane 416.
• the cathodic compartment 4321 may be the compartment between the ion-exchange membrane 416 and the cathode 432.
• the ion-exchange membrane 416 of the carbon dioxide electrolysis unit 430 may comprise a cation-exchange membrane 413.
• the (first) carbon comprising stream 210 may be provided to the anodic compartment 4311.
• the anodic compartment 4311 comprises an anodic compartment inlet 4318 and an anodic compartment outlet 4319.
• the (first) carbon comprising stream 210 may be provided to the anodic compartment 4311 via the anodic compartment inlet 4318.
• the carbon comprising stream 210 is acidified in the anodic compartment 4311.
• the acidified (second) carbon comprising stream 220 may be provided by the anodic compartment 4311.
• the (second) carbon comprising stream may exit the anodic compartment 4311 via the anodic compartment outlet 4319.
• the carbon comprising stream 220 may have a pH of at most 7, such as at most 5, such as at most 3.
• the carbon comprising stream 220 may be provided to the cathodic compartment 4321.
• the cathodic compartment 4321 may comprise a cathodic compartment inlet 4328 and a cathodic compartment outlet 4329.
• the (second) carbon comprising stream 220 may be provided to the cathodic compartment 4321 via the cathodic compartment inlet 4328.
• the acidified carbon comprising stream 220 in the cathodic compartment 4321, may be converted in a first conversion process to provide: (i) a carbon monoxide comprising stream 230, and (ii) an alkaline solution 240.
• the following reactions may occur at the cathode 432: CO (g) + H2O.
• the carbon monoxide stream 230 may be provided from the cathodic compartment 4321 via the cathodic secondary outlet 4327.
• the carbon monoxide comprising stream 230 provided at the cathodic secondary outlet 4327 may be pressurized.
• hydroxide ions may be produced and protons may be consumed during the first conversion process.
• the production of hydroxide ions and consumption of protons may increase the pH in the cathodic compartment to at least 7, such as at least 9, such as at least 11.
• the change in pH may result in a change in the dominant carbon species in the (first) carbon comprising stream and the (second) carbon comprising stream.
• the (first) carbon comprising stream 210 may comprise a carbon dioxide content of cl wt.%.
• the (second) carbon comprising stream 220 comprises a carbon dioxide content of c2 wt.%.
• c2 > cl such as c2 > 2*cl, especially c2 > 5*cl.
• the second liquid provided by the cathodic compartment may be basic, and may comprise the alkaline solution 240.
• the second liquid comprising the alkaline solution 240 may exit the cathodic compartment 4321 via the cathodic compartment outlet 4329.
• the alkaline solution 240 may be provided to the feed input system 100.
• the feed input system 100 may comprise a feed input system inlet 108 and a feed input system outlet 109.
• the alkaline solution 240 may be provided to the feed input system 100 via the feed input system inlet 108.
• the alkaline solution 240 may be used to capture carbon dioxide in the feed input system 100.
• the feed input system 100 may provide the (first) carbon comprising stream 210.
• the carbon comprising stream 210 may exit the feed input system 100 via the feed input system outlet 109.
• the system 1000 may be configured such that in operation at least part of the first liquid from the anodic compartment 4311 is recirculated to the cathodic compartment 4321. Further, in embodiments, the system 1000 may be configured such that in operation at least part of the second liquid from the cathodic compartment 4321 is recirculated to the anodic compartment 4311.
• the pH of the first liquid in the anodic compartment 4311 may be changed from at least 9 to at most 5. Further, in embodiments, the pH of the second liquid in the cathodic compartment 4321 may be changed from at most 5 to at least 9.
• the cation-exchange membrane 413 may comprise negatively charged chemical groups, wherein the anion-exchange membrane 414 may comprise positively charged chemical groups, wherein the bipolar membrane 415 may comprise positively charged chemical groups and negatively charged chemical groups.
• the cation-exchange membrane 413 may be selected from the group of a natural or synthetic zeolite, or a sulfonated coal; wherein the anion-exchange membrane 414 may comprise a solid polymer electrolyte membrane comprising positive ionic groups, selected from quaternary ammonium (QA) functional groups and mobile negatively charged anions, and wherein the bipolar membrane 415 may further comprise a combination of the cation-exchange membrane 413 and the anion-exchange membrane 414.
• QA quaternary ammonium
• the carbon dioxide electrolysis unit 430 may comprise an anode selected from the group of Ni or Ti, a carbon based cathode, and a catalyst selected from the group of an oxide of one or more of Ag, Cu, Au, Ru, and Ir catalyst.
• the cathode, or the anode, or both may (already) comprise the catalyst.
• the anode may comprise a catalyst comprising Ru or Ir.
• the cathode may comprise catalysts of Ag, Cu, Au, and Zn.
• the system may comprise a methanol synthesis unit 440.
• the methanol synthesis unit 440 may be configured to pressurize the carbon monoxide comprising stream 230 to a pressure selected from the range of 50-100 bar, heat the carbon monoxide comprising stream 230 to a temperature selected from the range of 250-300°C. In further embodiments, the methanol synthesis unit 440 may be configured to pressurize an external hydrogen comprising stream 250 to a pressure selected from the range of 50-100 bar, and heat the external hydrogen comprising stream 250 to a temperature selected from the range of 250-300°C.
• the invention may be a method for providing a carbon monoxide stream using the system described herein.
• the method may comprise applying a potential difference selected from the range of 1.5-3V across the anode 431 and the cathode 432 of the carbon dioxide electrolysis unit 430.
• the method may comprise converting in a first conversion process a carbon comprising stream 210, 220 to provide: (i) a carbon monoxide comprising stream 230, and (ii) an alkaline solution 240; wherein the carbon comprising stream 210, 220 comprises one or more of carbon dioxide gas, carbonate ions, and bicarbonate ions in an aqueous solution.
• the method may comprise executing the first conversion process in the electrical cell comprising system 2000.
• the method may comprise pressurizing one or more of (i) the carbon comprising stream 210, and (ii) the carbon monoxide comprising stream 230 within at least part of the electrical cell comprising system 2000 at a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• the method may comprise converting the carbon monoxide comprising stream 230 to provide a methanol comprising stream 260 at a pressure of 50-100 bar and 250-300°C.
• the method may comprise recirculating at least part of the first liquid from the anodic compartment 4311 to the cathodic compartment 4321. Further, in embodiments, the method may comprise recirculating at least part of the second liquid from the cathodic compartment 4321 is recirculated to the anodic compartment 4311.
• the invention may provide a method to provide carbon monoxide and (optionally) hydrogen.
• the method may comprise contacting air or flue gas with the alkaline solution 240 to provide the carbon comprising stream 210, comprising recirculating the alkaline solution 240 within the system 1000. Furthermore, in embodiments, the method may comprise configuring the feed input system 100 to receive sea water, and wherein sea water comprises the carbon comprising stream 210.
• the method may comprise recirculating at least part of a first liquid from the anodic compartment 4311 to the cathodic compartment 4321, and recirculating at least part of a second liquid from the cathodic compartment 4321 to the anodic compartment 4311 (via the feed input system 100).
• the method may comprise changing the pH of the first liquid in the anodic compartment 4311 from at least 9 to at most 5, and changing the pH of the second liquid in the cathodic compartment 4321 from at most 5 to at least 9.
• the system may take one of two flow paths depending on the embodiment of the system.
• the first flow path may involve the capture of carbon dioxide from a carbon source such as air, flue gas or seawater using the feed input system 100.
• the feed input system 100 may use blowers to contact carbon dioxide with an alkaline solution 240.
• the carbon dioxide may be dissolved in the alkaline solution and may exist as carbonate ions or bicarbonate ions to provide the carbon comprising stream 210.
• the carbon comprising stream 210 may be provided to the anodic compartment of the carbon dioxide electrolysis unit 430.
• water may be oxidized to produce oxygen stream 280.
• the oxygen stream 280 may be separated and used in a later stage of the process.
• the remainder comprises an alkaline medium comprising carbonate ions and bicarbonate ions.
• the stream exiting at the anodic compartment may be a slightly acidic to neutral stream comprising carbon i.e. the carbon comprising stream 220.
• the change in the pH of the stream may result in a change in the dominant carbonic species.
• the decrease in pH may result in carbon out-gassing as dissolved carbon dioxide in the carbon comprising stream 220.
• the carbon comprising stream may be provided to the cathodic chamber of the carbon dioxide electrolysis unit 430.
• the dissolved pressurized carbon dioxide may be reduced at the cathode 432 to provide a pressurized carbon monoxide comprising stream 230.
• the cathode 432 may furnish hydroxide ions.
• the cations may react with the hydroxide ions to regenerate the alkaline solution 240.
• the alkaline solution 240 may be recirculated to the feed input system 100, for further carbon capture.
• Fig. 4 schematically depicts an embodiment of the system 1000 comprising a bipolar membrane electrodialysis unit 410 configured in the electrical cell comprising system 2000.
• the invention may be a system 1000 for providing carbon monoxide.
• the system 1000 may comprise an electrical cell comprising system 2000 further comprising a carbon dioxide electrolysis unit 430.
• the system 1000 may be configured to convert in a first conversion process a carbon comprising stream 210, 220 to provide: (i) a carbon monoxide comprising stream 230, and (ii) an alkaline solution 240.
• the system 1000 may be configured to execute the first conversion process in the electrical cell comprising system 2000.
• the electrical cell comprising system 2000 may comprise a bipolar membrane electrodialysis unit 410.
• the bipolar membrane electrodialysis unit 410 may comprise an anode 411, a cathode 412 and one or more repeating cell units 4110.
• the repeating cell unit 4110 further may comprise a combination of a cation-exchange membrane 413, an anion-exchange membrane 414, a bipolar membrane 415, an acidic compartment 531 and a basic compartment 532.
• the carbon comprising stream 210 may be provided to the acidic compartment 531.
• a recirculation stream 270 may be provided to the basic compartment 532.
• the recycle stream may also be referred to as the remainder stream.
• an acidic compartment 531 of the bipolar membrane electrodialysis unit 410 may be a compartment on the negatively charged side of the bipolar membrane 415, wherein the acidic compartment 531 is bordered by a second ion-exchange membrane, wherein the second ion-exchange membrane may comprise an anion-exchange membrane 414 or a cation-exchange membrane 413.
• a basic compartment 532 of the bipolar membrane electrodialysis unit 410 may be a compartment on the positively charged side of the bipolar membrane 415, wherein the basic compartment 532 is bordered by a second ion-exchange membrane, wherein the second ion-exchange membrane may comprise an anion-exchange membrane 414 or a cation-exchange membrane 413.
• the bipolar membrane electrodialysis unit 410 may be configured to apply a potential difference selected from the range of 0.6-2V, such as especially 1-1.5V per repeating cell unit 4110. Further, in embodiments the bipolar membrane electrodialysis unit 410 may be configured to provide the carbon comprising stream 220, and the alkaline solution 240. In embodiments, the bipolar membrane electrodialysis unit 410 may further comprise a water dissociation catalyst layer, wherein the water dissociation catalyst comprises Al 3+ 0(0H), or Fe 3+ O(OH), or Al-silicates, or Ni-based catalyst.
• the potential difference applied across the bipolar membrane electrodialysis unit 410 may be larger than the potential difference applied across the carbon dioxide electrodialysis unit 430.
• the bipolar membrane electrodialysis unit 410 may produce more H + and OFF than the carbon dioxide electrolysis unit 430.
• the high production of OH' in the bipolar membrane electrodialysis unit 410 may increase the pH of the alkaline solution 240 provided by the basic compartment 532 to at least 7, such as at least 9, such as at least 11.
• the amount of OH' produced in the cathodic compartment 4321 may be less than the amount of H + produced in the acidic compartment 531.
• the recirculation stream 270 may have a pH of at most 7, such as at most 5, such as at most 3.
• an acidic compartment 531 of the bipolar membrane electrodialysis unit 410 may be a compartment on the negatively charged side of the bipolar membrane 415, wherein the acidic compartment 531 is bordered by a second ion-exchange membrane, wherein the second ion-exchange membrane may comprise an anion-exchange membrane 414 or a cation-exchange membrane 413.
• a basic compartment 532 of the bipolar membrane electrodialysis unit 410 may be a compartment on the positively charged side of the bipolar membrane 415, wherein the basic compartment 532 is bordered by a second Ion-exchange membrane, wherein the second ion-exchange membrane may comprise an anion-exchange membrane 414 or a cation-exchange membrane 413.
• the system may be configured to take a second flow path.
• carbon dioxide may be captured from a source such as air, flue gas or seawater using the feed input system 100.
• the feed input system 100 may use blowers to dissolve carbon dioxide in the alkaline solution 240 (for example the alkaline stream may comprise one or more of KOH and NaOH), which may act as the capture solvent.
• the alkaline nature of the capture solvent may allow the capture of carbon dioxide in the form of carbonate ions and bicarbonate ions. Further, these ions may be captured in the alkaline solution as metallic carbonates and metallic bicarbonates such as K2CO3, Na2COs, KHCO3, and NaHCCf.
• the alkaline medium (or solution) 240 with the dissolved ions may be the carbon comprising stream 210.
• the carbon comprising stream 210 may be pressurized to a pressure selected from the range of 10-70 bar, such as specifically 30-50 bar.
• sea water comprising dissolved carbon may be used as the carbon comprising stream.
• the bipolar membrane electrodialysis unit 410 may comprise a number of repeating cell units 4110 further comprising a cation-exchange membrane 413, an anion- exchange membrane 414 and a bipolar membrane 415.
• the repeating cell units 4110 in embodiments, may comprise acidic compartment 531 and basic compartments 532.
• the acidic compartment 531 may comprise an acidic compartment inlet 5318 and an acidic compartment outlet 5319.
• the basic compartments 532 may comprise a basic compartment inlet 5328 and a basic compartment outlet 5329.
• the (first) carbon comprising stream 210 may enter the acidic compartment(s) 531 via the acidic compartment inlet(s) 5318.
• the (first) carbon comprising stream 210 may be provided to the acidic compartment 531 which may be contained between a positively charged anion-exchange membrane 414 or a negatively charged cation-exchange membrane 413 and a bipolar membrane 415.
• the basic compartment 532 may be configured between the cation-exchange membrane 413 and the bipolar membrane 415.
• the (first) carbon comprising stream 210 may be converted into the (second) carbon comprising stream 220 within the acidic compartment 531.
• the (second) carbon comprising stream 220 may be rich in carbon dioxide (and carbonic acid), due to the acidic nature of the stream in the acidic compartment 531.
• the carbon comprising stream(s) 210, 220 may be pressurized and hence, the carbon dioxide may remain dissolved in the acidic stream.
• the (second) carbon comprising stream 220 may be provided to the cathodic compartment of the carbon dioxide electrolysis unit 430.
• the (second) carbon comprising stream 220 may flow from the acidic compartment outlet 5319 to the cathodic compartment inlet 4328.
• the dissolved carbon dioxide may be reduced electrochemically at the cathode 432 of the carbon dioxide electrolysis unit 430 to provide a high-pressure gaseous carbon monoxide comprising stream 230.
• the carbon monoxide comprising stream 230 may be extracted from the cathodic compartment.
• the carbon monoxide comprising stream 230 may exit the cathodic compartment via the cathodic compartment outlet 4329.
• the cathodic compartment outlet 4329 may also provide a liquid comprising the recirculation stream 270.
• the recirculation stream 270 may be provided back to the bipolar membrane electrodialysis unit 410.
• this stream (i.e., the recirculation stream 270) may in embodiments be provided to the basic compartment inlet(s) 5328 of the bipolar membrane electrodialysis unit 410.
• the cations i.e. alkali metal ions such as Na + and K + may be recombined with the hydroxide ions furnished by the bipolar membrane(s) 415 to regenerate the alkaline solution 240.
• the alkaline solution 240 may be provided to the anodic compartment of the carbon dioxide electrolysis unit 430.
• the alkaline solution 240 may flow from the basic compartment outlet(s) 5329 to the anodic compartment inlet 4318.
• water may be oxidized to produce gaseous oxygen stream 280.
• gaseous oxygen stream 280 may be separated and used in a later stage of the process.
• the alkaline solution 240 exiting from the anodic compartment
• the ion exchange membrane 416 of the carbon dioxide electrolysis unit 430 may comprise a cation exchange membrane 413, or an anion exchange membrane 414, or a bipolar membrane 415.
• the basic compartment 532 may comprise a pH of at least 7, such as a pH of at least 9, especially a pH of at least 11.
• the acidic compartment 531 may comprise a pH of at most 7, such as a pH of at most 5, especially a pH of at most 3.
• the alkaline solution 240 may comprise a carbon content of c3 wt.%.
• the recirculation stream 270 may comprise a carbon content of c4 wt.%.
• c4 > c3 such as c4 > 2*c3, especially c4 > 5*c3.
• the alkaline solution 240 may flow from the anodic compartment outlet 4319 to the feed input system inlet 108.
• the pressurized carbon monoxide comprising stream 230 may be used in the production of methanol in the subsequent methanol synthesis step.
• an external hydrogen stream 250 may be supplied to the methanol synthesis unit 440 for the production of methanol.
• system 1000 may be configured to pressurize the alkaline solution 240 within at least part of system 1000 at a pressure selected from the range of 10-70 bar, such as especially 30-50 bar.
• system 1000 may be configured such that the acidic compartment 531 is configured upstream of the cathodic compartment 4321. Further, in embodiment, the system 1000 may be configured such that the basic compartment 532 is configured upstream of the anodic compartment 4311.
• the system 1000 may be configured such that in operation at least part of the first liquid from the anodic compartment 4311 is recirculated to the cathodic compartment 4321 via the feed input system 100 and the bipolar membrane electrodialysis unit 410. Further, in embodiments, the system 1000 may be configured such that in operation at least part of the second liquid from the cathodic compartment 4321 is recirculated to the anodic compartment 4311 via the bipolar membrane electrodialysis unit 410.
• the ion-exchange membrane 416 of the carbon dioxide electrolysis unit 430 comprises a cation-exchange membrane 413, or an anion-exchange membrane 414, or a bipolar membrane 415.
• the invention may provide a method to provide carbon monoxide and (optionally) hydrogen, especially by means of the BPMED unit.
• the method may comprise applying a potential difference selected from the range of 0.6-2V per repeating cell unit 4110 in a bipolar membrane electrodialysis unit 410; the method comprising providing the carbon comprising stream 220, and the alkaline solution 240.
• the method may comprise increasing the pH within the basic compartment to at least 9, and lowering the pH in the acidic compartment to at most 5.
• the method may comprise flowing a liquid from the acidic compartment 531 to the cathodic compartment 4321, wherein the acidic compartment 531 is configured upstream of the cathodic compartment 4321; and the method comprising flowing a liquid from the basic compartment 532 to the anodic compartment 4311, wherein the basic compartment 532 is configured upstream of the anodic compartment 4311.
• the method may comprise recirculating at least part of the first liquid from the anodic compartment 4311 to the cathodic compartment 4321 via the feed input system 100 and the bipolar membrane electrodialysis unit 410, and the method comprising recirculating at least part of the second liquid from the cathodic compartment 4321 to the anodic compartment 4311 via the bipolar membrane electrodialysis unit 410.
• the method may comprise applying a potential difference selected from the range of 1.2-3V across the anode 421 and the cathode 422 of a water electrolysis unit 420, wherein the water electrolysis unit 420 comprises an anode 421 and a cathode 422, the method comprising electrolyzing water in the water electrolysis unit 420 to provide the hydrogen comprising stream 250.
• the electrolysis of carbon dioxide may provide the pressurized carbon monoxide comprising stream 230 which may be necessary for providing a methanol comprising stream 260 in the methanol synthesis unit 440.
• the carbon monoxide comprising stream 230 may be further pressurized to a pressure selected from the range of 50-100 bar.
• the carbon monoxide comprising stream 230 may be heated to a temperature selected from the range of 250 - 300 °C.
• carbon monoxide comprising stream 230 may be used to produce methanol in standard methanol synthesis process.
• the methanol synthesis unit 440 may use a copper-zinc based catalyst.
• the terms “substantially” or “essentially” herein, and similar terms, will be understood by the person skilled in the art.
• the terms “substantially” or “essentially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially or essentially may also be removed.
• the term “substantially” or the term “essentially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%.
• the terms “about” and “approximately” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%.
• the article "a” or “an” preceding an element does not exclude the presence of a plurality of such elements.
• the invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer.
• a device claim, or an apparatus claim, or a system claim enumerating several means, several of these means may be embodied by one and the same item of hardware.
• the mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
• the invention also provides a control system that may control the device, apparatus, or system, or that may execute the herein described method or process. Yet further, the invention also provides a computer program product, when running on a computer which is functionally coupled to or comprised by the device, apparatus, or system, controls one or more controllable elements of such device, apparatus, or system.
• the invention further applies to a device, apparatus, or system comprising one or more of the characterizing features described in the description and/or shown in the attached drawings.
• the invention further pertains to a method or process comprising one or more of the characterizing features described in the description and/or shown in the attached drawings.
• a method or an embodiment of the method is described being executed in a device, apparatus, or system, it will be understood that the device, apparatus, or system is suitable for or configured for (executing) the method or the embodiment of the method, respectively.

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