NL2031327B1

NL2031327B1 - Carbon capture and conversion

Info

Publication number: NL2031327B1
Application number: NL2031327A
Authority: NL
Inventors: Wagterveld Martijn; Jorrit Bleeker Jan; Arie Vermaas David; Sharifian Rezvan
Original assignee: Univ Delft Tech
Priority date: 2022-03-18
Filing date: 2022-03-18
Publication date: 2023-09-29
Also published as: WO2023177298A3; WO2023177298A2

Abstract

The invention is a system (1000) for providing carbon monoxide and hydrogen. Especially, the system (1000) comprises an electrical cell comprising system (2000). Especially, the electrical cell comprising system (2000) comprises a carbon dioxide electrolysis unit (430). Further the carbon dioxide electrolysis unit (430) comprises an anode (431), a cathode (432), and an ion-exchange membrane further comprising a cation-exchange membrane (413), or an anion-exchange membrane (414), or a bipolar membrane (415), wherein the carbon dioxide electrolysis unit (430) is conﬁgured to apply a potential difference selected from the range of 1.5-3V across the anode (431) and the cathode (432). Especially, the system (1000) is 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), wherein the carbon comprising stream (210, 220) comprises one or more of carbon dioxide gas, carbonate ions, and bicarbonate ions in an aqueous solution. Especially, the system (1000) is conﬁgured to electrolyze water in a second conversion process to provide a hydrogen comprising stream (250). Further, the system (1000) is conﬁgured to execute the ﬁrst conversion process and the second conversion process in the electrical cell comprising system (2000). Yet further, the system (1000) is 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. 30

Description

Carbon capture and conversion

FIELD OF THE INVENTION

The invention relates to a system to convert carbon dioxide. Further, the present invention provides a method to convert carbon dioxide electrochemically.

BACKGROUND OF THE INVENTION

EP3741864A 1 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 water- dissociating bipolar membrane on the cathode side and the ion-selective anion-exchange membrane; ¢) transporting the carbon dioxide in the form of hydrogen carbonate-anions and/or carbonate-anions across the anion-exchange membrane from the basic compartment into the acidic compartment comprising an acidic, aqueous solution; d) contacting the carbon dioxide in the acidic, aqueous solution from step (c) and hydrogen with at least one acetogenic cell in an aqueous production medium under suitable conditions to produce at least one organic acid and/or alcohol from the carbon dioxide in the acidic, aqueous solution; and optionally e) recovering the organic acid and/or alcohol.

SUMMARY OF THE INVENTION

Development of carbon capture technology is paramount to achieving a net zero carbon dioxide emission. An integral part of controlling carbon dioxide emissions relates to achieving a “circular economy” i.e. it is not only important to capture carbon dioxide but it also important to do so sustainably and to utilize the captured carbon dioxide productively. 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. Further, these systems rely on regenerating carbon dioxide via energy-intensive temperature swings i.e, these systems utilize the variation in the solubility of carbon dioxide as a function of temperature to capture and regenerate carbon dioxide. This suffers from the drawback of being an energy intensive process. Moreover, capturing carbon dioxide using temperature swing absorption may not be sustainable, especially to capture carbon from dilute sources where the low yield of carbon captured does not justify the enormous cost (monetarily and in terms of energy) of using a temperature swing approach. Further, approximately 40% of the CO: emission is decentralized, which may increase further in the future when power plants and industry transition to using renewable energy. In such a context, there remains a massive challenge to close the carbon cycle.

Electrochemical methods of capturing carbon dioxide are promising especially for capturing carbon from dilute sources, however, most electrochemical methods currently available are in early stages of development and are still energy intensive.

Another facet of carbon capture technology is aimed at utilizing the captured carbon productively. In that vein, there is a necessity to transition from fossils fuels to renewable carbon sources for the production of carbon-based chemicals. Carbon dioxide is a viable sustainable alternative to fossil fuels as a source of carbon. Industrial effluents, atmospheric air, and dissolved carbon dioxide in the ocean are sources of carbon. Reusing the carbon in these sources may not only help as a feed for the production of these chemicals but may also reduce the dependence on fossil fuels. Hence, there has been development of carbon capture technologies, which allow carbon dioxide from the above-mentioned sources to be captured. Further, there have been developments of systems to convert the captured carbon into various chemical products. However, most of these systems operate independently and hence may suffer from a low overall efficiency. Presently, scaling energy storage using conventional energy technology (batteries) may be challenging. Alternatively, dense energy carriers store energy in the form of chemical bonds of hydrocarbons such as methane, ethanol, ethylene, and methanol.

Carbon dioxide in its gaseous form is non-reactive under ambient conditions.

However, alternatively 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 1s 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. Hence, achieving a global net zero greenhouse gasses emission requires further development of this technology. Drawbacks of a carbon dioxide electrolyzer using a vapor-phase CO; may be water management of the gas diffusion electrode, and/or the relatively high crossover of carbonic species to the anolyte. Moreover, a separate CO; capture step, releasing the CO: in gas state, and subsequent conversion in another reactor, may require substantial energy to release the CO: from the capture medium.

Hence, it 1s an aspect of the invention to provide an alternative system to provide carbon monoxide and hydrogen, which preferably further at least partly obviates one or more of above-described drawbacks. 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.

Hence, in a first aspect the invention may be a system for providing carbon monoxide and hydrogen. In embodiments, the system may comprise an electrical cell comprising system. In further embodiments, the electrical cell comprising system may comprise a carbon dioxide electrolysis unit. Especially, in embodiments, the carbon dioxide electrolysis unit may comprise an anode, a cathode, and an ion-exchange membrane. In embodiments, the ion-exchange membrane may further comprise a cation-exchange membrane (or “CEM”), or an anion-exchange membrane (or “AEM”), or a bipolar membrane. In embodiments, 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. In embodiments the system may be configured to convert in a first conversion process a carbon comprising stream to provide: (1) a carbon monoxide comprising stream, and (ii) an alkaline solution. Especially, in embodiments the carbon comprising stream may comprise one or more of carbon dioxide (COz), carbonate ions (CO;%), and bicarbonate ions (HCOs") in an aqueous solution. The term “hydrogen carbonate ions” may also be used to refer to bicarbonate ions. In embodiments, 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 (1) 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. More especially, in embodiments the invention provides a system for providing carbon monoxide and hydrogen. Especially, the system comprises an electrical cell comprising system. Especially, the electrical cell comprising system comprises a carbon dioxide electrolysis unit. Further, 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.

Especially, 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. Especially, the system is configured to convert in a first conversion process a carbon comprising stream to provide: (1) a carbon monoxide comprising stream, and (ii) an alkaline solution. Specifically, the carbon comprising stream comprises one or more of carbon dioxide, carbonate ions, and bicarbonate ions in an aqueous solution. Especially, the system is configured to electrolyze water in a second conversion process to provide a hydrogen comprising stream. Especially, the system is configured to execute the first conversion process and the second conversion process in the electrical cell comprising system. Further, the system is 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.

The term “carbon” refers to the carbon present in the (chemical) compounds comprising carbon. The term “carbonic species” refers to dissolved carbon dioxide (CO:), bicarbonate (or “hydrogen carbonate”) ions (HCO5"), and carbonate ions (CO).

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. The term “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. The term “medium” may essentially also refer to a solution and may be used interchangeably as such. The term “pH” is known to the skilled person as the 5 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 (or having a low pH value) leads to carbon dioxide gas out-gassing from the solution comprising carbon. Basification of the solution (or a having a high pH value) leads to absorption of carbon dioxide gas increasing the DIC. Further, 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*), or bicarbonate ions (HCO:"). 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.

It is desirable to have a larger current density, as this may be particularly advantageous in effectively scaling up electrochemical systems. 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).

Moreover, carbon dioxide has high solubility at high pressure, which may ensure that the carbon dioxide remains dissolved during the electrolysis process. Also, 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.

Moreover, the use of a liquid can aid in the temperature control of the reactor.

In embodiments, 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. In embodiments, the system may comprise an electrical cell comprising system. In embodiments, the electrical cell comprising system may further comprise other systems, particularly to carry out electrochemical reactions. In embodiments, 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. In further embodiments, the electrical cell comprising system may comprise a carbon dioxide electrolysis unit. The carbon dioxide electrolysis unit, in embodiments, may be configured to reduce carbon dioxide to carbon monoxide, hence facilitating the system to provide the carbon monoxide comprising stream. In embodiments, the carbon monoxide comprising stream may comprise carbon monoxide, such as at least 10 vol.%, more especially at least about 30 vol.%, like especially at least about. 50 vol. % carbon monoxide. In specific embodiments the carbon monoxide comprising stream may comprise carbon monoxide in an amount of at least 60 vol. % carbon monoxide, such as especially 70 vol. % carbon monoxide, such as especially 80 vol. % carbon monoxide. Hence, in embodiments, the carbon dioxide electrolysis unit may provide a mixed gas stream comprising carbon monoxide. The carbon monoxide comprising stream may optionally further comprise one or more of ethylene, formic acid, hydrogen and ethanol. Also, in embodiments, unreacted carbon dioxide may be present in the carbon monoxide comprising stream. In embodiments, a ratio of a volume percentage 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. In embodiments the of a volume percentage of carbon monoxide of the carbon comprising stream may be essentially 0 vol.%. In embodiments, the carbon dioxide electrolysis unit may comprise an anode, a cathode, and an ion-exchange membrane. In embodiments, the carbon dioxide electrolysis unit may comprise two compartments, an anodic compartment, and a cathodic compartment. Further, in embodiments, the anode may be configured in the anodic compartment and the cathode may be configured in the cathodic compartment. In yet further embodiments, 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. In embodiments, the ion- exchange membranes may contain pores that may limit the transfer of certain species of compounds or ions based on their molecular size. Further, in embodiments, the ion-exchange membranes may be charged and hence may repel or attract certain charged species or ions.

Hence, 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. In embodiments, the ion-exchange membranes may further comprise a cation-exchange membrane, or an anion-exchange membrane, or a bipolar membrane. Cation-exchange membranes are negatively charged membranes, anion-exchange membranes are positively charged membranes, and bipolar membranes are a combination of anion-exchange membranes and cation-exchange membranes.

In embodiments, the carbon dioxide electrolysis unit may be configured to apply a potential difference selected from the range of 1.5-3V 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 CO; — CO + 1/20,, 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 (CO, CO, O2), temperature, pH, etc. However, note that this reaction is the overall reaction which comprises two other equations that are carried out at the cathode and at the anode

In embodiments, the reduction of carbon dioxide to carbon monoxide takes place at the cathode, according to the equation: CO, + 2H" + 2e —CO + H;0, and simultaneously, an oxygen evolution reaction (or “OER”) may take place at the anode according to the equation:

H:0 — 1/20: + 2H" + 2¢". The combination of these two reactions results in the overall reaction of splitting or reducing carbon dioxide to carbon monoxide with the evolution of oxygen as a biproduct. In embodiments, 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. Hence, in embodiments, 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. In embodiments, the carbon comprising stream may be acidified in the anodic compartment. Especially, 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. In embodiments, 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. Further, at the cathode, H" is consumed resulting in an abundance of OH ions, which also leads to basification of the medium in the cathodic compartment. In embodiments, the cation-exchange membrane (being negatively charged) may promote the transfer of alkali metal ions M" across the cation- exchange membrane. The positively charged M" ions may be attracted towards the cathode and in embodiments, may be conducted across the cation-exchange membrane to the cathodic chamber. In embodiments, the metal ions M" may be reacted with the excess OH to regenerate the alkaline medium MOH. Thus, in embodiments, the cathodic compartment may provide the carbon monoxide comprising stream from reduction of carbon dioxide and additionally regenerate the alkaline solution. In embodiments, the use of the cation-exchange membrane is essential to regenerating the alkaline solution. In embodiments, the regenerated alkaline solution may be reused for the capture of carbon dioxide. In embodiments, the conversion of carbon dioxide to carbon monoxide may be the first conversion process. In embodiments, 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. Thus, in embodiments, oxygen may be produced as a biproduct of the second conversion process. Hence, in embodiments, the system may provide carbon monoxide by executing the first conversion process and the system may provide hydrogen by executing the second conversion process. In embodiments, the system may be configured to execute the first conversion process and the second conversion process in the electrical cell comprising system.

Further, 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 at a pressure selected from the range of 10- 70 bar, such as especially 30-50 bar. In embodiments, 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. This may also provide the advantage of decreasing the cell voltage applied across the carbon dioxide electrolysis unit. Further, in embodiments, 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.

In embodiments, 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. In embodiments, the system may comprise a feed input system. In further embodiments the feed input system may be configured to contact air or flue gas with the alkaline solution to provide the carbon comprising stream. In embodiments, the alkaline solution may be recirculated within the system. In embodiments, the alkaline solution may be used by the feed input system to capture carbon dioxide to provide a carbon comprising stream. Especially, the carbon comprising stream is provided to the electrical cell comprising system. Especially, 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. Hence, 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. Further, 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. In embodiments, the alkaline solution (or medium) may be used as the capture solvent. In embodiments, 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. In embodiments, the first conversion process recovers the alkaline solution from the carbon comprising stream. In further embodiments, the alkaline solution may be reused to capture carbon dioxide, thereby increasing the captured carbon content in the system. In embodiments, 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. In embodiments, 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.

In embodiments, the feed input system may be configured to receive sea water, and the carbon comprising stream may comprise sea water. Carbon dioxide dissolves in sea water and hence, may be a source of carbon. Further, the presence of salts in seawater may provide the advantage of being an abundant and cheap source of electrolyte. For these reasons, in embodiments, sea water may be directly used as the carbon comprising stream. Using seawater in the system may further provide the advantage of generating other useful compounds for the production of chemicals such as HCI, chlorine containing polymers and bleaching agents.

In embodiments, the electrical cell comprising system may comprise a bipolar membrane electrodialysis unit. In further embodiments, the bipolar membrane electrodialysis unit may comprise an anode, a cathode and one or more repeating cell units. In embodiments, the repeating cell unit may further comprise a combination of a cation-exchange membrane, an anion-exchange membrane, or a bipolar membrane. In embodiments, 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. In embodiments, the system may be configured to provide the carbon comprising stream, and the alkaline solution. In embodiments wherein the system comprises a bipolar membrane electrodialysis unit, the carbon dioxide electrolysis unit may contain a bipolar membrane, a cation-exchange membrane or an anion- exchange membrane. The advantage of using a bipolar membrane in the carbon dioxide electrolysis unit is that the produced alkalinity of the CO: 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. Moreover, the crossover of dissolved inorganic carbon species may be reduced when using a bipolar membrane compared to an anion-exchange membrane.

In embodiments, the bipolar electrodialysis unit may comprise the anode and the cathode. In embodiments, the cathode may comprise a combination of lithium and metals such as nickel, manganese, cobalt, and aluminum. In embodiments, anode materials may comprise graphite, platinum, and copper. The bipolar 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. In further embodiments, 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. In embodiments, 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. In embodiments, a plurality of repeating cell units, each comprising a different combination of membranes may be used. In specific embodiments, the repeating cell unit may comprise in order a cation-exchange membrane, a bipolar membrane, and an anion-exchange membrane. Further, 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. Hence, in embodiments 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’ 1ons). In embodiments, the bipolar 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. In embodiments, the cell units may be selected and arranged between the anode and the cathode in the bipolar electrodialysis unit such that they form an alternating series of acidic and basic compartments.

In embodiments, a potential difference selected from the range of 0.6-2V, such as especially 1-1.5V may be applied per repeating cell unit between the anode and the cathode.

For example, in embodiments, a potential difference in the range 24-80V may be applied across the anode and the cathode of a bipolar 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 electrodialysis unit (by increasing the number of repeating cell units). Scaling of the size of the bipolar 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. In embodiments, 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. Further, the bipolar membrane may furnish protons and hydroxide ions upon application of an electrical field. Yet further, 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.

In embodiments, 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 electrodialysis unit before being provided to the carbon dioxide electrolysis unit. In particular, in embodiments, the carbon comprising stream captured in an alkaline medium (in the feed input system) may be provided to 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. In such embodiments (where the bipolar membrane electrodialysis unit may be configured before 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. In embodiments, the remainder stream may be directed back to the basic compartment(s) of the bipolar electrodialysis unit. In embodiments, 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.

In embodiments, the cation-exchange membrane may comprise negatively charged chemical groups. In embodiments, the anion-exchange membrane may comprise positively charged chemical groups. In embodiments, 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.

Similarly, the cation-exchange membrane may contain fixed anionic groups with predominantly mobile cations. Further, most of the conductivity is the result of the cations transport. 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. In embodiments, the cation- exchange membrane may be selected from the group of a natural or synthetic zeolite, or a sulfonated coal. In embodiments, 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. In embodiments, the bipolar membrane further comprising a combination of the cation-exchange membrane and the anion- exchange membrane.

In embodiments, the bipolar membrane may further comprise a water dissociation catalyst layer. In further embodiments, the water dissociation catalyst may comprise AI**O(OH), or Fe’'O(OH). In yet further embodiments, 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. In embodiments, the water dissociation catalyst layer may be configured at the junction of cation- exchange layer and the anion-exchange layers, which continuously takes in water into the junction and dissociates the feedwater into H*/OH 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 and basic compartments, respectively.

In embodiments, the electrical cell comprising system may comprise a water electrolysis unit. In further embodiments, the water electrolysis unit may comprise an anode and a cathode. In embodiments, 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. In embodiments, the water electrolysis unit may be configured to electrolyze water to provide the hydrogen comprising stream. In addition to a source of carbon, a hydrogen comprising stream may also be required to manufacture hydrocarbon-based chemicals. In embodiments, water may be provided to the water electrolysis unit. In embodiments, the water electrolysis unit may be configured to apply a potential difference between the anode and the cathode of the water electrolysis unit. This may split water to provide hydrogen and oxygen. Thus, in embodiments 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. In embodiments, water may be oxidized at the anode to provide oxygen. In further embodiments, water may be reduced to provide hydrogen at the cathode. In embodiments, oxygen may be extracted as a stream from the water electrolysis unit. In further embodiments, oxygen may be used in the production of hydrocarbon-based compounds. In embodiments, the hydrogen evolved may be directed from the water electrolysis unit to provide the hydrogen comprising stream (in the second conversion process).

In embodiments, the water electrolysis unit may comprise an anode selected from the group comprising one or more of RuOx-based, or IrOx-based, or RulrOx-based, or

Ni-based materials. In embodiments, 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. In embodiments, 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. In embodiments, cathode material may comprise platinum electrodes coated with nickel and carbon. In embodiments, the anode material may be nickel, cobalt or iron. In embodiments, RuOx-based, IrOx-based, or RulrOx-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. In embodiments, electrolytes may be added to reduce the potential difference required for the electrolysis of water. In embodiments, electrolytes may be cations of metals such as Li, Rb, K,

Cs, Ba, Sr, Ca, Na and Mg. In further embodiments, strong acids such as sulfuric acid and strong bases such as potassium hydroxide or sodium hydroxide may be added as electrolytes.

In yet further embodiments, an ion-exchange membrane such as a solid polymer electrolyte may be used. For example, a Nafion membrane may effectively split water molecules on either side of the membrane at a potential difference of 1.4-1.6V.

The terms RuOx-based, IrOx-based, and RulrOx, refer to ruthenium oxide, iridium oxide, and ruthenium iridium oxide, respectively.

In embodiments, the system may comprise a hydrocarbon synthesis unit. In embodiments, the hydrocarbon synthesis unit may be a methanol synthesis unit. In further embodiments, 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. In further embodiments, 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. In embodiments, methanol may be produced with high selectivity. In embodiments, the synthesis may be carried out at 250-300 °C. In embodiments, the synthesis may be carried out at a pressure selected from the range of 50-100 bar, such as especially 60-80 bar. In embodiments, the methanol synthesis unit may use copper-based catalysts for methanol synthesis. In embodiments, 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. In further embodiments, 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. In embodiments, the hydrocarbon synthesis unit may be configured to produce alkanes according to the reaction: (2n+1)H2 + nCO — CyHan2 + nH>O. Hence, in embodiments, the hydrocarbon synthesis unit may comprise a Fischer-

Tropsch process reactor.

In a second aspect, the invention may be a method for providing carbon monoxide and hydrogen using the system. In embodiments, 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. In embodiments, 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. Especially, in embodiments the carbon comprising stream may comprise one or more of carbon dioxide gas, carbonate ions, and bicarbonate ions in an aqueous solution. In embodiments, the method may comprise electrolyzing water in a second conversion process to provide a hydrogen comprising stream.

In embodiments, the method may comprise executing the first conversion process and the second conversion process in an electrical cell comprising system. In embodiments, the method may comprise pressurizing one or more of (1) the carbon comprising stream, and (11) 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.

In embodiments, 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. Especially, converting in a first conversion process a carbon comprising stream to provide: (1) a carbon monoxide comprising stream, and (ii) an alkaline solution.

Especially, electrolyzing water in a second conversion process to provide a hydrogen comprising stream. Especially, executing the first conversion process and the second conversion process in the electrical cell comprising system and 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.

In embodiments, 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). In embodiments, the method may comprise reducing carbon dioxide to carbon monoxide at the cathode, according to the equation: CO; + 2H" + 2e —CO + H:O, and simultaneously, executing an oxygen evolution reaction (or “OER”) at the anode according to the equation: HaO — 40, + 2H" + 2e’. The combination of these two reactions results in the overall reaction of splitting or reducing carbon dioxide to carbon monoxide with the evolution of oxygen as a biproduct. In embodiments, 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. In embodiments, the method may comprise reacting the metal ions M* with the excess OH to regenerate the alkaline medium MOH (such as comprising NaOH or KOH). Thus, in embodiments, the method may comprise reducing carbon dioxide to carbon monoxide at the cathodic compartment and additionally regenerating the alkaline solution. In embodiments, method may comprise reusing the regenerated alkaline solution for the capture of carbon dioxide. In embodiments, the method may comprise converting carbon dioxide to carbon monoxide in a first conversion process. In embodiments, the method may comprise executing a second conversion process, comprising electrolyzing water to provide a hydrogen comprising stream. Hence, in embodiments, the method may comprise providing carbon monoxide by executing the first conversion process and providing hydrogen in the second conversion process. In embodiments, the method may comprise executing the first conversion process and the second conversion process in the electrical cell comprising system. Further, in embodiments 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.

In embodiments, 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. In embodiments, the method may comprise providing the carbon comprising stream, and the alkaline solution. In embodiments, the method may comprise providing streams of solutions to each acidic and basic compartment in the bipolar membrane electrodialysis unit. In embodiments, 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. For example, in embodiments, the method may comprise applying a potential difference in the range 24-80V across the anode and the cathode of a bipolar electrodialysis unit comprising 40 repeating cell units. In embodiments, 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 electrodialysis unit before being provided to the carbon dioxide electrolysis unit. In particular, in embodiments, 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. In embodiments, the method may comprise providing the acidified carbon comprising stream to the cathodic compartment of the carbon dioxide electrolysis unit. In such embodiments (where the bipolar membrane electrodialysis unit may be configured before the carbon dioxide electrolysis unit), the method may further comprise providing the carbon monoxide comprising stream to the cathodic compartment of the carbon dioxide electrolysis unit, and providing a remainder stream comprising metal ions. In embodiments, the method may comprise directing the remainder stream back to the basic compartments of the bipolar electrodialysis unit. In embodiments, the method may comprise regenerating the alkaline solution by reacting the hydroxide ions furnished in the basic compartment of the bipolar membrane electrodialysis unit with the alkali metal ions in the remainder stream. In embodiments, the method may further comprise routing the regenerated alkaline solution through the anodic compartment of the carbon dioxide electrolysis cell back to the feed input system. In further embodiments, the method may comprise reusing the alkaline solution to capture carbon dioxide.

In embodiments, 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 250C-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. In embodiments, the method may comprise using catalysts selected from the group comprising one or more of Cu, ZnO, and

Al;0:3. In embodiments, the method may comprise reacting carbon monoxide with hydrogen according to the equation: CO + 2H; — CH;0H. In embodiments, additional reactions may also take place in the methanol synthesis unit, such as (1) unreacted carbon dioxide in the carbon monoxide comprising stream may react with hydrogen (CO; + 3H, — CH30H + H;0) to produce methanol and water, and (ii) carbon monoxide in the carbon monoxide comprising stream may react with water (CO + HO — CO: + Hz). Hence, in embodiments, the methanol comprising stream may comprise methanol, steam, carbon dioxide, carbon monoxide, and hydrogen. In specific embodiments, 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.

In addition to producing carbon dioxide, it also important to store or utilize carbon in way that does not further add to the global carbon footprint. Electricity generation from sustainable sources such as solar energy or wind energy may help reduce green-house gas emissions. This energy may be used directly or stored, typically in a battery. However, conventional battery technology may only be able to store and provide power in the order of a few hours to a few days. Scaling up of conventional batteries faces additional challenges. A promising alternative to storing energy in batteries may be to store abundant energy in dense energy carriers. In the dense energy carriers the energy may be stored in the form of chemical bonds of chemicals such as methane, ethanol, ethylene, ammonia and methanol. Thus, electrochemical reduction of carbon dioxide to provide these chemicals may be particularly advantageous.

Hence, amongst others, 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.

BRIEF DESCRIPTION OF THE EMBODIMENTS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which: 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. The schematic drawings are not necessarily to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Fig. 1 schematically depicts an embodiment of the system 1000 to provide carbon monoxide and hydrogen. In embodiments, the system 1000 may comprise an electrical cell comprising system 2000. Especially, in embodiments the electrical cell comprising system 2000 may comprise a carbon dioxide electrolysis unit 430. Further, in embodiments the carbon dioxide electrolysis unit 430 may comprise an anode 431, a cathode 432, and an ion-exchange membrane further comprising a cation-exchange membrane 413, or an anion-exchange 414 membrane, or a bipolar membrane 415. In further embodiments, 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. In embodiments, the system 1000 may be configured to convert in a first conversion process a carbon comprising stream 210, 220 to provide: (1) a carbon monoxide comprising stream 230, and (11) an alkaline solution 240. In embodiments, the carbon comprising stream 210, 220 may comprise one or more of carbon dioxide, carbonate ions, and bicarbonate ions in an aqueous solution. In embodiments, the system 1000 may be configured to electrolyze water in a second conversion process to provide a hydrogen comprising stream 250. Further, in embodiments, the system 1000 may be configured to execute the first conversion process and the second conversion process in the electrical cell comprising system 2000. Especially in embodiments, 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. In embodiments, the system 1000 according to any one of the preceding claims, may comprise a feed input system 100. In embodiments, 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. In embodiments, the alkaline solution 240 may be recirculated within the system 1000. In alternative embodiments, the feed input system 100 may be configured to receive sea water, and wherein the carbon comprising stream 210 may comprise the sea water. Further, in embodiments, 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. In embodiments, 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. Additionally, in embodiments, the electrical cell comprising system 2000 may comprise a water electrolysis unit 420. In further embodiments, the water electrolysis unit 420 may comprise an anode 421 and a cathode 422. In embodiments, 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. In embodiments, the water electrolysis unit 420 may comprise an anode selected from the group comprising one or more of RuOx-based, or IrOx-based, or RulrOx-based, or Ni-based materials. In embodiments, 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. Especially, 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.

In embodiments, 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. 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. In embodiments, the system may comprise a methanol synthesis unit 440. In further embodiments, 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.

Further, the invention may be a method for providing a carbon monoxide and a hydrogen comprising stream using the system according to claim 1. In embodiments, 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. In embodiments, the method may comprise converting in a first conversion process a carbon comprising stream 210, 220 to provide: (1) 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. In embodiments, the method may comprise electrolyzing water in a second conversion process to provide a hydrogen comprising stream 250. In embodiments, the method may comprise executing the first conversion process and the second conversion process in the electrical cell comprising system 2000. In embodiments, 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. In embodiments, 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 250C-300°C.

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. In embodiments, 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. In embodiments, the carbon comprising stream 210 may be provided to the anodic compartment of the carbon dioxide electrolysis cell 430. In the anodic compartment, water may be oxidized to produce oxygen. In embodiments, the oxygen may be separated and used in a later stage of the process. The remainder comprises an alkaline medium comprising carbonate ions and bicarbonate ions. At the anode 431, there may be a release of protons, which may subsequently acidity the alkaline medium. Hence, 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.

In embodiments, the carbon comprising stream may be provided to the cathodic chamber of the carbon dioxide electrolysis unit 430. In the cathodic compartment, 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.

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. In embodiments, the invention may be a system 1000 for providing carbon monoxide and hydrogen. Especially, in embodiments the system 1000 may comprise an electrical cell comprising system 2000 further comprising a carbon dioxide electrolysis unit 430. In embodiments, 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 (it) an alkaline solution 240. In embodiments, the system 1000 may be configured to electrolyze water in a second conversion process to provide a hydrogen comprising stream 250.

Further, in embodiments, the system 1000 may be configured to execute the first conversion process and the second conversion process in the electrical cell comprising system 2000. In embodiments, the electrical cell comprising system 2000 may comprise a bipolar membrane electrodialysis unit 410. In embodiments, the bipolar membrane electrodialysis unit 410 may comprise an anode 411, a cathode 412 and one or more repeating cell units. Further, in embodiments the repeating cell unit further may comprise a combination of a cation-exchange membrane 413, an anion-exchange membrane 414, and a bipolar membrane 415. In embodiments, the bipolar membrane electrodialysis unit 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.

Further, in embodiments the bipolar membrane electrodialysis unit may be configured to provide the carbon comprising stream 220, and the alkaline solution 240. In embodiments, the bipolar membrane electrodialysis unit may further comprise a water dissociation catalyst layer,

wherein the water dissociation catalyst comprises AlI**O(OH), or Fe**O(OH), or Al-silicates, or Ni-based catalyst. In embodiments, the electrical cell comprising system 2000 may comprise a water electrolysis unit 420.

In embodiments, the streams comprised in the system may be configured to take a second flow path. In the second flow path, in embodiments, carbon dioxide may be captured from a source such as air, flue gas or seawater using the feed input system 100. In embodiments, for the capture of gaseous carbon dioxide, 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

K;CO3, Na2CO3, KHCO:, and NaHCO:. In embodiments, the alkaline medium (or solution) 240 with the dissolved 10ns may be the carbon comprising stream 210. In embodiments, 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. In other embodiments, sea water comprising dissolved carbon may be used as the carbon comprising stream. In embodiments, the bipolar membrane electrodialysis unit 410 may comprise a number of repeating cell units further comprising a cation-exchange membrane 413, an anion-exchange membrane 414 and a bipolar membrane 415. The repeating cell units, in embodiments, may comprise acidic and basic compartments.

The carbon comprising stream 210 may be provided to the acidic compartment which may be contained between a positively charged anion-exchange membrane 414 and a bipolar membrane 415. The basic compartment may be between the cation-exchange membrane 413 and the bipolar membrane 415. In embodiments, 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. In embodiments, the carbon comprising stream(s) 210, 220 may be pressurized and hence, the carbon dioxide may remain dissolved in the acidic stream. In embodiments, 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. In embodiments, the carbon monoxide comprising stream 230 may be extracted from the cathodic compartment. In embodiments, the (remainder) carbon comprising stream 220 may be provided back to the bipolar membrane electrodialysis unit 410. Especially, this stream in embodiments, may be provided to the basic compartment(s) of the bipolar membrane electrodialysis unit 410. In embodiments, 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. In embodiments, the alkaline solution 240 may be provided to the anodic compartment of the carbon dioxide electrolysis unit 430. At the anode 431, water may be oxidized to produce gaseous oxygen. In embodiments, the gaseous oxygen may be separated and used in a later stage of the process. In further embodiments, 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. In embodiments, the pressurized carbon monoxide comprising stream 230 may be used in the production of methanol in the subsequent methanol synthesis step.

In embodiments, regardless of the two flow paths, 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. In embodiments, 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. At this point in the process, in embodiments, 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. In further embodiments, 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 term “plurality” refers to two or more. Furthermore, the terms “a plurality of” and “a number of” may be used interchangeably.

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. Where applicable, 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%.

Moreover, 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%. For numerical values it is to be understood that the terms “substantially”, “essentially”,

“about”, and “approximately” may also relate to the range of 90% - 110%, such as 95%-105%, especially 99%-101% of the values(s) it refers to.

The term “comprise” also includes embodiments wherein the term “comprises” means “consists of”.

The term “and/or” especially relates to one or more of the items mentioned before and after “and/or”. For instance, a phrase “item 1 and/or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term "comprising" may in an embodiment refer to "consisting of" but may in another embodiment also refer to "containing at least the defined species and optionally one or more other species”.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

The devices, apparatus, or systems may herein amongst others be described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation, or devices, apparatus, or systems in operation.

The term “further embodiment” and similar terms may refer to an embodiment comprising the features of the previously discussed embodiment, but may also refer to an alternative embodiment.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, “include”, “including”, “contain”, “containing” and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.

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. In 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.

Moreover, if a method or an embodiment of the method is described being executed 1n 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.

The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.

Claims

Conclusions

1. A system (1000) for providing carbon monoxide and hydrogen; wherein the system (1000) comprises an electric cell system (2000); wherein the electric cell system (2000) comprises a carbon dioxide electrolysis unit (430); wherein: - the carbon dioxide electrolysis unit (430) comprises an anode (431), a cathode (432), and an ion exchange membrane further comprising a cation exchange membrane (413), or an anion exchange membrane (414), or a bipolar membrane (415); wherein the carbon dioxide electrolyzer (430) is 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) is configured to convert, in a first conversion process, a carbon-containing stream (210, 220) to provide: (1) a carbon monoxide stream (230), and (ii) an alkaline solution (240) ; wherein the carbon-containing stream (210, 220) comprises one or more of carbon dioxide, carbonate ions, and bicarbonate ions in an aqueous solution; and - the system (1000) is configured to electrolyze water in a second conversion process to provide a hydrogen-containing stream (250); - the system (1000) is configured to perform the first conversion process and the second conversion process in the electric cell system (2000); and - the system (1000) is configured to pressurize one or more of (i) the carbon-containing stream (210, 220) and (ii) the carbon monoxide-containing stream (230) within at least a portion of the electric cell comprising system (2000) at a pressure selected from the range 10-70 bar.

The system (1000) according to any preceding claim, comprising a power input system (100); wherein the feed input system (100) is configured to contact air or flue gas with the alkaline solution (240) to provide the carbon-containing stream (210); wherein the alkaline solution (240) is recirculated within the system (1000).

The system (1000) of claim 2, wherein the feed input system (100) is configured to receive seawater, and wherein the carbon-containing stream (210) comprises the seawater.

The system (1000) according to any one of the preceding claims, wherein the electric cell system (2000) comprises a bipolar membrane electrodialysis unit (410), wherein the bipolar membrane electrodialysis unit (410): - an anode (411), a cathode (412), and one or more repeating cell units; wherein the repeating cell unit further comprises a combination of a cation exchange membrane (413), an anion exchange membrane (414), and a bipolar membrane (415); - is configured to apply a potential difference selected from the range of 0.6-2V per repeating cell unit; - is configured to provide the carbon-containing stream (220) and the alkaline solution (240).

The system (1000) of any preceding claim, wherein the cation exchange membrane (413) comprises negatively charged chemical groups, wherein the anion exchange membrane (414) comprises positively charged chemical groups, wherein the bipolar membrane (415) positively charged chemical groups and negatively charged chemical groups.

The system (1000) according to any one of the preceding claims, wherein the cation exchange membrane (413) is selected from the group of a natural or synthetic zeolite, or a sulfonated carbon; wherein the anion exchange membrane (414) comprises 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) further comprises a combination of the cationic exchange membrane (413) and the anion exchange membrane (414).

The system (1000) of any preceding claim, wherein the bipolar membrane (415) further comprises a water dissociation catalyst layer, wherein the water dissociation catalyst is Al'*O(OH), or Fe)' O(OH), or Ai -silicates, or Ni-based catalyst.

The system (1000) according to any one of the preceding claims, wherein the electric cell system (2000) comprises a water electrolysis unit (420), the water electrolysis unit (420): - an anode (421) and a cathode (422) includes; - is configured to apply a potential difference selected from the range of 1.2-3V across the anode (421) and the cathode (422); - is configured to electrolyze water to provide the hydrogen-containing stream (250).

The system (1000) according to claim 8, wherein the water electrolysis unit (420) comprises: - an anode selected from the group comprising one or more RuOx-based, or IrOx-based, or RulrOx-based, or Ni-based materials; - a metal-based cathode, wherein the metal is selected from the group comprising one or more of Pt, Ru, Ir and Ni; and

- 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 system (1000) of claim 8, wherein the carbon dioxide electrolysis unit (430) comprises 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, Zn, Ru, and Ir catalysts.

The system (1000) according to any one of the preceding claims, comprising a methanol synthesis unit (440), wherein the methanol synthesis unit (440) is configured for: - pressurizing a mixture of the carbon monoxide stream (230 ) and the hydrogen-containing stream (250) to a pressure selected from the range of 50-100 bar; - heating the mixture to a temperature selected from the range of 250-300°C.

A method (1) for providing carbon monoxide and hydrogen using the system (1000) according to any one of the preceding claims, comprising: - 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); - converting a carbon-containing stream (210, 220) in a first conversion process to provide: (i) a carbon monoxide stream (230), and (ii) an alkaline solution (240); wherein the carbon-containing stream (210, 220) comprises one or more of carbon dioxide gas, carbonate ions and bicarbonate ions in an aqueous solution; and

- electrolyzing water in a second conversion process to provide a hydrogen-containing stream (250); - carrying out the first conversion process and the second conversion process in the electric cell system (2000); and - pressurizing one or more of (i) the carbon-comprising stream (210), and (ii) the carbon monoxide stream (230) within at least a portion of the electric cell system (2000) at a pressure selected from the range 10-70 bar.

The method according to the preceding claim, comprising: - applying a potential difference selected from the range of 0.6-2V per repeating cell unit in a bipolar membrane electrodialysis unit (430); - providing the carbon-containing stream (220), and the alkaline solution (240).

The method according to the preceding claim, comprising converting the carbon monoxide stream (230) and the hydrogen stream (250) to provide a methanol stream at a pressure of 50-100 bar and 250C-300°C.