Modular electrolyzer stack and process for converting carbon dioxide to gaseous products at high pressure and high conversion rates

Abstract

The present invention relates to the field of converting gaseous carbon dioxide to vapor phase products at high pressures and high conversion rates via electrolysis performed by novel multi-stack CO electrolyzer cells (100") having novel gas and fluid flow structures formed within the bipolar plate assemblies used to construct the individual stacks (40) of cells (100").

Description

[Technical field]

[0001] The present invention relates to the field of producing gas phase products at high pressure and with high conversion rates via electrolysis of gaseous carbon dioxide. The invention thus also relates to a novel modular electrolyser for carrying out the electrolysis and thus converting carbon dioxide gas into various gas phase products, preferentially ready to be used as feedstock in further industrial processes. stack Regarding. [Background technology]

[0002] Carbon dioxide (CO2) is a greenhouse gas, and thus its conversion into transportation fuels and commodity chemicals using renewable energies is a value-added approach to simultaneous product creation and environmental remediation of carbon emissions. The large amount of chemicals produced worldwide that could potentially be derived from the electrochemical reduction (and hydrogenation) of CO2 further highlights the importance of this strategy. Electrosynthesis of chemicals using renewable energies (e.g. solar or wind energy) contributes to a greener and more sustainable chemical industry. Polymer electrolyte membrane (PEM)-based electrolyzers are particularly attractive due to the diversity of possible CO2-derived products. Several industrial entities have shown interest in such technology, ranging from energy / utility companies to oil and gas companies, including cement production and processing companies.

[0003] Similar to PEM-based water electrolysers (i.e. H2 / O2 generators), a typical configuration of a PEM-based CO2 electrolyser consists of two flow paths, one for the anolyte and one for the catholyte, separated by an ion exchange membrane in direct contact with the catalyst. The cathode electrocatalyst is immobilized on a porous gas diffusion layer (GDL), which is typically in contact with the flowing liquid catholyte, while CO2 gas is pumped through the GDL. This arrangement overcomes some of the known problems in the field, namely: (i) current limitation due to low concentration of CO2 at the electrode, (ii) the inability to pass H2 from the anode through the membrane, and (iii) the inability to pass H2 from the anode through the membrane. +(iii) diffusion of the products to the anode, where they are oxidized (product crossover), resulting in acidification of the catholyte and consequent increase in H release selectivity. Although such equipment is not currently commercially available on an industrial scale, most of its components (i.e., GDL and catalyst), as well as a laboratory-sized setup (approximately 5 cm 2 Electrode sizes) are already available. Nevertheless, the design and operating conditions of PEM-based CO2 electrolysers have to be carefully optimized for CO2 electrolysis.

[0004] A comprehensive review on PEM-based CO2 electrolysis is provided, for example, in Progress in Energy and Combustion Science 62 (2017) pp.133-154, where the parameters influencing the performance of flow CO2 electrolyzers are discussed in detail. The analysis covers the basic design concept of the electrochemical cell (either microfluidic or membrane-based), the materials used (e.g. catalysts, supports, etc.), as well as the operating conditions (e.g. type of electrolyte, role of pressure, temperature, etc.).

[0005] European Patent Application Publication No. 3,375,907A1 is a single cell Disclosed is a carbon dioxide electrolysis device in the form of an electrolytic cell, which includes: an anode portion including an anode for oxidizing water or hydroxide ions to produce oxygen, a cathode for reducing carbon dioxide to produce carbon compounds, a cathode portion including a cathode solution flow path for supplying a cathode solution to the cathode and a gas flow path for supplying carbon dioxide to the cathode, a separator for separating the anode portion from the cathode portion, and a differential pressure control unit for controlling the differential pressure between the pressure of the cathode solution and the pressure of carbon dioxide so as to regulate the production amount of carbon dioxide produced by the reduction reaction in the cathode portion.

[0006] US Patent Application Publication No. 2018 / 0274109A1 discloses a single electrolytic cell including a refresh material supply unit including a gas supply unit for supplying a gaseous substance to at least one of an anode and a cathode, and a refresh control unit for stopping the supply of current from a power source and the supply of carbon dioxide and an electrolyte based on a required standard of the cell output of the electrolytic cell, and for operating the refresh material supply unit. cell This invention relates to carbon dioxide electrolysis devices.

[0007] US Patent Application Publication No. 2013 / 0105304A1 relates to methods and systems for the electrochemical conversion of carbon dioxide to organic products including formate and formic acid. One embodiment of the system includes a first electrochemical cell including a high surface area cathode and a cathode compartment including a bicarbonate-based liquid catholyte saturated with carbon dioxide. The system also includes an anode and an anode compartment including a liquid acidic anolyte. The first electrochemical cell is configured to generate a product stream upon application of an electrical potential between the anode and the cathode. Further embodiments of the system may include a separate second electrochemical cell similar to and in fluid communication with the first.

[0008] US 2016 / 0369415 A1 discloses a catalyst layer for use in electrochemical devices, particularly electrolyzers whose feed includes at least one of CO2 and H2O. The catalyst layer includes a catalytically active element and an ionically conductive polymer. The ionically conductive polymer includes positively charged cyclic amine groups. The ionically conductive polymer includes at least one of imidazolium, pyridinium, pyrazolium, pyrrolidinium, pyrrolium, pyrimidium, piperidinium, indolium, triazinium, and polymers thereof. The catalytically active elements include at least one of V, Cr, Mn, Fe, Co, Ni, Cu, Sn, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Ir, Pt, Au, Hg, Al, Si, In, Tl, Pb, Bi, Sb, Te, U, Sm, Tb, La, Ce, and Nd.

[0009] US Patent Application Publication No. 2017 / 0321334A1 is a CO x A membrane electrode assembly (MEA) for use in a reduction reactor is taught. The MEA has a cathode layer including a reduction catalyst and a first ion-conducting polymer, and an anode layer including an oxidation catalyst and a second ion-conducting polymer. A PEM including a third ion-conducting polymer is arranged between the anode layer and the cathode layer. The PEM provides ionic communication between the anode layer and the cathode layer. There is also a cathode buffer layer, a cathode buffer, between the cathode layer and the PEM including a fourth ion-conducting polymer. There are three classes of ion-conducting polymers: anion conductors, cation conductors, and cation and anion conductors. At least two of the first, second, third, and fourth ion-conducting polymers are from different classes of ion-conducting polymers.

[0010] WO 2017 / 176600A1 relates to an electrocatalytic process for CO2 conversion. The process employs a novel catalyst combination that aims to overcome one or more of the limitations of low rate, high overpotential and low electron conversion efficiency (i.e. selectivity), low rate for catalytic reactions and high power requirements for sensors. The catalyst combination or mixture comprises at least one catalytically active element in the form of supported or unsupported particles, the particles having an average particle size of about 0.6 nm to 100 nm, preferably 0.6 nm to 40 nm, most preferably 0.6 nm to 10 nm. The catalyst combination also comprises a helper polymer that can, for example, contain a positively charged cyclic amine group, e.g., imidazolium or pyridinium. The catalytic combination of catalytically active element and helper polymer serves as a single catalyst for the conversion of CO2 to various reaction products. One electric It is very useful when used in the cathode catalyst layer of a gas-chemical cell.

[0011] US Patent No. 10,208,385 B2 describes a single process for converting CO2 into various products, among others, CO. One electricA carbon dioxide electrolysis device is disclosed having a dissolution cell, the cell including a cathode, an anode, a carbon dioxide supply unit, an electrolyte supply unit, and a separator for separating the cathode and the anode from each other. Besides the cell, the carbon dioxide electrolysis device further includes a power source, a reaction control unit for causing reduction and oxidation reactions by passing a current from the power source to the anode and the cathode. The cell is supplied with gaseous CO2 on the cathode and liquid electrolyte at least on the anode side. The gas and liquid(s) are distributed in the cell through gas and liquid flow paths (formed in the cathode and anode current collectors), respectively.

[0012] As is evident from the above, most of the prior art in the field of CO2 electrolysis is cell The focus is on developing novel catalysts to enhance activity and product selectivity using structures. At the same time, in simple batch electrochemical cells, the maximum achievable rate for the reaction is often limited by the low solubility of CO2 in water (~30 mM). Similar problems arise when the solution (catholyte) is delivered to the cathode of a continuous-flow electrolyzer, so a direct CO2 gas feed (i.e., electrolyte-free) electrolyzer cell would be preferred.

[0013] Thus, it will be necessary to increase the CO2 conversion rate to a level of practical significance. In other words, a high conversion rate (e.g., at least 150 mA cm) is required to overcome mass transport limitations. -2 A continuous-flow, direct CO gas delivery setup and process to carry out electrochemical CO reduction with a current density of 1000 sq. m would be required.

[0014] There is widespread agreement in the art that in order to operate this process in an economically attractive manner, it is important to (i) produce as selectively as possible either product, (ii) product that has economic value, and (iii) product that is easily separated. Thus, to achieve these objectives, an electrolytic cell operating as follows: / stack You will need: High current density (leading to high reaction rates), High faradaic efficiency for the desired product(s) (i.e., a large proportion of the total current invested (Σ i j i ) is product formation (j product ), thus resulting in high selectivity towards a given product,

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[0015] Electrolyser Cell / stack If a process does not meet any of these criteria, it will not be able to compete with other non-electrochemical technologies on a practical scale.

[0016] Therefore, the new CO2 electrolyzer stack and processes are also needed, in this case to meet the above goals. stack The structure and operating parameters are optimized.

[0017] Furthermore, especially for industrial applications, large cell Base module CO2 electrolyser stack , i.e. more than one, preferably several electrolytic cells cell Multi consisting of cell electrolytic cell stack It would also be necessary to provide cell can be manufactured relatively easily and cheaply.

[0018] In most cases, industrial CO2 sources provide gaseous CO2 at high pressure. Moreover, industrial processes utilizing various gas-phase carbon-based substances, such as, for example, synthesis gas, carbon monoxide, methane, ethane, ethylene, etc., as feedstocks to produce other products require high pressure feedstocks, where hereinafter the term "high pressure" refers to differential pressure values ​​comprised in the range from about 0 bar up to about 30 bar. [Prior art documents] [Patent documents]

[0019] [Patent Document 1] European Patent Application Publication No. 3375907 [Patent Document 2] US Patent Application Publication No. 2018 / 0274109 [Patent Document 3] US Patent Application Publication No. 2013 / 0105304 [Patent Document 4] US Patent Application Publication No. 2016 / 0369415 [Patent Document 5] US Patent Application Publication No. 2017 / 0321334 [Patent Document 6] International Patent Application Publication No. 2017 / 176600 Brochure [Patent Document 7] U.S. Patent No. 10,208,385 Summary of the Invention [Problem to be solved by the invention]

[0020] Taking this into consideration, a CO2 electrolyser that can withstand high pressure, especially on its cathode side, is stack would clearly be needed.

[0021] A further object of the present invention is to provide a CO electrolyser that can be easily and simply rebuilt when changes in the required production rate or even in the type of product occur. stack The purpose of this project is to provide

[0022] Additional objects, as well as aspects, features and advantages of the present invention are set forth in the following description. [Means for solving the problem]

[0023] The above goal is to achieve a continuous flow multi- Cellular or multi-layer electrolytic cell stack This is achieved by the present invention. stack Further preferred embodiments of the invention are as set forth in claims 2 to 14 The object is to provide a process for converting starting gaseous carbon dioxide into final gas-phase product(s). 15 This is further achieved by the CO2 electrolyser setup according to the present invention. set up Preferred embodiments of are defined by claims 14 to 21. The above object is also achieved by a method for converting gaseous carbon dioxide, CO2, into at least one gas phase product according to claim 22. Preferred variants of this method are set out in claims 23 and 24. [Brief description of the drawings]

[0024] In the following, the invention will be described in detail with reference to the accompanying drawings.

[0025] [Figure 1] FIG. 1 shows a simplified operation of a carbon dioxide electrolyser set-up according to the present invention, in which (humidified) CO2 gas is used at the cathode side of the electrolyser cell / stack and conditioned anolyte is supplied at the anode side. [Figure 2A] FIG. 2 is a schematic cross-sectional view of a single layer electrolyzer cell that can be used in the carbon dioxide electrolyzer set-up shown in FIG. [Figure 2B] FIG. 2B is an enlarged view of a portion of the cell illustrated in FIG. 2A. [Figure 3A] A complete upper perspective view of a particular exemplary embodiment of an electrolytic cell stack according to the invention having three cells used to convert carbon dioxide gas into various gas phase products. [Figure 3B] A complete lower perspective view of a particular exemplary embodiment of an electrolytic cell stack according to the invention having three cells used to convert carbon dioxide gas into various gas phase products. [Figure 4] A partial exploded view of a multi-cell electrolytic cell stack according to the invention, including n cells, with one electrolytic cell exploded. [Diagram 5] A bottom view of a bipolar plate assembly consisting of two preferred components, used as the first (anode) component of the intermediate electrolytic cell (cell i + 1) of the stack and the second (cathode) part of the adjacent intermediate electrolytic cell (cell i) of the stack, where 0 < i < n - 1, and i and n are integers. [Figure 5A] A cross-sectional view of the bipolar plate assembly shown in FIG. 5 for the A - A cross-section. [Figure 5B] A cross-sectional view of the bipolar plate assembly shown in FIG. 5 for the B - B cross-section. [Figure 6] A cross-sectional view of a 3-cell stack for the A - A cross-section shown in FIG. 3A, assembled to achieve a parallel flow configuration from the perspective of the CO2 supply to the stack, where the system of flow paths and cavities shown in gray represents the path of the gas flow from the CO2 inlet to the CO2 and product outlet within the stack. [Figure 7] A cross-sectional view of a 3-cell stack for the A - A cross-section shown in FIG. 3A, assembled to achieve a series flow configuration from the perspective of the CO2 supply to the stack, where the system of flow paths and cavities shown in gray represents the path of the gas flow from the CO2 inlet to the CO2 and product outlet within the stack. [Figure 8]FIG. 3B is a cross-sectional view of a 3-cell stack taken along cross section B-B shown in FIG. 3A in a series / parallel configuration, where the system of channels and cavities shown in grey represent the fluid (i.e., anolyte) flow path within the stack from the anolyte inlet to the anolyte and anode product (particularly O2 if water is used as the anolyte) outlet. [Figure 9] 9 shows various flow patterns formed at the surface of the cathode current collector used in an electrolyser stack according to the present invention, where Figures 9(a) to (c) show some exemplary designs where CO2 is fed into the cell at the centre and CO2 is collected from the cell along an outer peripheral ring, while figure (d) shows a further exemplary design where CO2 is fed into the cell at the periphery of the cathode current collector and CO2 is also collected from the cell at the periphery of the cathode current collector after passing through a double helix pattern, but at a location opposite to the point where the CO2 is introduced. [Figure 10A] FIG. 13 shows a possible preferred embodiment of an anode side spacer element used to achieve a serial gas flow configuration between two adjacent cell / bipolar plate assemblies in a multi-cell electrolyzer stack upon assembly. [Figure 10B] FIG. 13 shows a possible preferred embodiment of an anode side spacer element used to achieve a parallel gas flow configuration between two adjacent cell / bipolar plate assemblies in a multi-cell electrolyzer stack upon assembly. [Figure 11A] FIG. 6 shows a possible preferred embodiment of the anode current collector, i.e., the anode portion of the bipolar plate assembly in FIG. 5, in a top view, formed with a flow pattern on one of its sides, highlighting the cavity formed for O-ring sealing. [Figure 11B] 5 shows a possible preferred embodiment of the anode current collector, i.e., the anode portion of the bipolar plate assembly in FIG. 5, in a bottom view, formed with a flow pattern on one of its sides, highlighting the cavity formed for O-ring sealing. [Figure 12A]FIG. 13 is an exploded view of a single cell in a multi-layer electrolyzer stack assembled in a series or parallel gas flow configuration. [Figure 12B] FIG. 13 is an exploded view of a single cell in a multi-layer electrolyzer stack assembled in a series or parallel gas flow configuration. [Figure 13] Figure 2 shows the effect of increasing the number of individual electrolyzer cells applied in an electrolyzer stack according to the invention assembled in either series or parallel gas flow configurations, in particular plot (a) plots the CO2 conversion during electrolysis at ΔU=-2.75 V / cell that can be achieved with a 1-cell and a 3-cell series connected electrolyzer at different CO2 feed rates, and plot (b) shows the CO2 conversion during electrolysis at different cell voltages that can be achieved with an electrolyzer stack composed of one cell or three cells connected in parallel (with identical cell normalized gas feed). [Figure 14] FIG. 1 shows current density vs. operating cell-voltage of a 3-cell CO2 electrolyzer stack according to the invention used for synthesis gas (H2 / CO mixture over Ag catalyst) or hydrocarbon (CH4 and C2H4 over Cu catalyst) formation recorded with a cathode gas diffusion electrode (GDE) containing different catalysts at a ν=10 mV s-1 sweep rate by linear sweep voltammetry (LSV). [Figure 15] FIG. 13 is a chronoamperometric curve obtained at ΔU=−3 V / cell for a 3-cell CO2 electrolyzer stack according to the present invention using a cathode GDE containing 1 mg cm-2 Ag fixed on Sigracet 39BC carbon paper by spray coating. [Figure 16] FIG. 1 shows gas chromatograms recorded during chronoamperometric measurements at ΔU=−2.75 V / cell performed with a 3-cell CO2 electrolyser stack according to the invention and using Ag catalyst [plot (a)] or Cu catalyst [plot (b)]. [Figure 17]The partial current densities (left ordinate) and the partial current density ratios (right ordinate) for CO and H2 formation at different stack voltages are shown (obtained by chronoamperometry and gas chromatography measurements). [Figure 18] Partial current densities for H2 and CO formation (left ordinate) and CO2 conversion (right ordinate) during electrolysis at ΔU=-2.75 V as a function of the amount of Ag catalyst in the cathode GDE. [Figure 19] Partial current densities for H2 and CO formation (left ordinate) and CO2 conversion (right ordinate) during electrolysis at ΔU=-2.75 V as a function of the applied cathode spacing. [Figure 20] FIG. 1 shows the partial current density for H2 and CO formation (left ordinate) and CO2 conversion (right ordinate) during electrolysis at ΔU=−2.75 V as a function of the depth of the flow pattern applied at the cathode side of the electrolyzer stack according to the invention. [Figure 21] FIG. 1 shows the partial current density (left ordinate) for H2 and CO formation during electrolysis at ΔU=−2.75 V as well as the CO2 conversion (right ordinate) as a function of the carbon dioxide flow rate (normalized with the surface area) in the cathode compartment of an electrolyzer stack according to the invention. [Figure 22] FIG. 1 shows the partial current density (left ordinate) for H2 and CO formation during electrolysis at ΔU=-2.75 V and CO2 conversion (right ordinate) as a function of anolyte (1 M KOH) temperature (at a feed rate of about 9 cm3 cm-2 min-1) occurring in an electrolyzer stack according to the invention. [Diagram 23] FIG. 1 shows LSV curves recorded at v=10 mV s-1 sweep rate under various CO2 differential pressures during electrolysis performed in an electrolyzer stack according to the present invention. [Figure 24] 1 shows the current density at different stack voltages (Plot A) and the partial current density ratio during electrolysis at ΔU=−2.75 V (Plot B) as a function of CO2 differential pressure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] In particular, the present invention provides a carbon dioxide electrolyser capable of operating at high differential pressures and high conversion rates. stack It relates to novel components and novel assemblies for electrochemical reduction of gaseous carbon dioxide to gas-phase products (see Table 1 below) and oxidation reactions (e.g., water oxidation, HO-2e) on the cathode and anode sides, respectively. - =2H + +0.5O2), the carbon dioxide used is preferentially humidified and then stack is sent inside.

[0027] [Table 1]

[0028] Due to the proposed technical novelty and modular construction, the proposed electrolyser stack The structure is highly scalable and flexible. stack maintains pressure resistance while maintaining its size / dimensions and the cell The number of CO2 electrolysis multilayer Based on a new concept of morphological composition, CO2 electrolyzer stack is constructed, in this case cell The number can even be up to 10 or more, preferably ranging from 2 to 7, more preferably from 3 to 6, and most preferably it is 3, or 4, or 5, or 6.

[0029] moreover, stack Depending on the structure, each electrolytic cell cell can be combined in parallel or in series or in a mixed manner from the gas management point of view. stack It has been found that by changing only one element of (and rearranging the others), the operation can be switched from series to parallel. Thus, stackcan be operated to achieve either exceptionally high conversion rates or conversion efficiencies as required. The catalysts, gas diffusion layers and ion exchange membranes employed allow flexibility in the production of different gas phase products. This allows the CO2 electrolyser according to the invention to stack The present invention allows for applications in various industries, such as the chemical, petroleum, and energy industries. stack With appropriate routine modifications, it can be used in other electrochemical setups (e.g., N2-reduction for ammonia production) without being limited to stack ) can be applied as well.

[0030] In the present invention, several cell The (electrocatalyst layers and membrane) are connected (electrically) in series and confined by a bipolar plate assembly, with one cell as the anode of the cell (similar to a PEM fuel cell or water electrolyser).

[0031] Specific Multi Cell Stack The structure is such that each of the electrolytic cells cell This is achieved by the application of a two-component bipolar plate assembly in the formation of a bipolar plate assembly, where the first component of a given bipolar plate assembly is cell and a second component of the bipolar plate assembly forms an anode portion of the cell Arranged next to cell In this way, a series of electrolytic cells cell can be formed, stack Some flow structure elements of the cathode / anode flow path in the cathode section, i.e., cavities and channels for gas flow for the cathode section, and stack Cavities and channels for liquid flow for the anode portion of the bipolar plate are provided on / in and between the opposing surfaces of the first and second components of the bipolar plate assembly.

[0032] Furthermore, the series / parallel flow channel configuration can be achieved by selectively forming ring-shaped spacer elements, i.e., anode side distances, which in effect stack When the electrolytic cell is assembled, stack The spacer elements support the subsequent bipolar plate assemblies with through channels within the electrolytic cell, and in particular in keeping with the modular structure, two different types of spacer elements are provided, the first type having a single internal gas transport channel at the periphery of the spacer element, and the second type having two gas transport channels located diametrically opposite each other at the periphery of the spacer element. stack When assembling the bipolar plate assemblies, the use of a first type of spacer element between subsequent bipolar plate assemblies stack This allows for the formation of continuous gas flow paths within the individual cell teeth stack In terms of gas management, the use of a second type of spacer element between subsequent bipolar plate assemblies stack The formation of gas flow passages having parallel sections within each cell Within each of cell Gas flow path stack (connected in parallel from the perspective of gas management). The use of the particular spacer element can equally include series and parallel sections. multilayer electrolytic cell stack It also becomes possible to establish structured gas flow paths within the

[0033] That is, the function of the bipolar plate assemblies and end units is complex: (i) they form current collectors in contact with the catalyst layer, and (ii) they serve as the reactants transporting the reactants to the catalyst layer through channels formed in these plates. stack (iii) responsible for the delivery of reactants to the active area and the proper exit of products; stack In addition, they contribute to the mechanical strength of the electrolytic cell. stackThey also play an important role in the thermal management of the element. To this end, a system of in-plane channels is formed on each of the elements within its surface to increase the surface area and aid the transport process. The channels are organized for the first time into various flow field designs of specific geometries that are specifically optimized.

[0034] CO2 electrolyser according to the present invention stack A further component used in is a custom-designed fabricated anode side structural element made of titanium (Ti) frit (Ti-frit). Said Ti-frit is made of Ti powders with different average particle sizes. The Ti-frit is actually manufactured by pressing Ti-particles. The anode catalyst is deposited directly on this Ti-frit, for example by wet chemical synthesis, or is synthesized separately and subsequently fixed on the Ti-frit.

[0035] CO2 electrolyser according to the present invention stack For the cathode catalyst applied in the present invention, it is fixed on a high surface area carbon support (i.e., GDL) that is in direct contact with the bipolar plate assembly. CO2 gas is delivered to the catalyst through this GDL. At the same time, the catalyst is in direct contact with the PEM, allowing easy ion transport.

[0036] CO2 electrolyser according to the present invention stack Further additional components employed within the present invention include both, i.e. stack The pressure chambers are formed in specific end units arranged at the cathode and anode ends of the cell provides adaptive pressure control on the cell This structure provides uniform pressure distribution throughout the stack It prevents deformation of the body, thus avoiding a reduction in the contact area between the internal components. This allows for stable operation even under high pressure. stack Importantly, the application of the terminal units stackThis eliminates the requirement for moving parts (e.g., pistons or valves) or elastic-plastic elements as a means of pressure control within the electrolytic cell. Furthermore, unlike external pressure control, the employment of a pressure chamber at the end unit is inherently safer, since the pressure within the pressure chamber can be controlled by the pressure in the electrolytic cell. cell In order to ensure electrochemical performance independent of pressure, the pressure chambers are applied in pairs, i.e. one for the electrolytic cell according to the invention, and the other for the electrolytic cell according to the invention. stack one is the cathode side and the other is the anode side.

[0037] FIG. 1 shows a cathode 101 on the cathode side, an anode 103 on the anode side, and a separator 102 for separating the cathode 101 and the anode 102 from each other. stack 100 CO2 electrolyzer (electrochemistry) used to produce gaseous products at high pressure and with high conversion by electrolysis of gaseous CO2 fed into the stack 1 shows an exemplary embodiment of a CO electrolyzer setup 200 including a separator 100, where the separator 102 is preferably a PEM element (e.g., an anion exchange membrane or a cation exchange membrane or a bipolar membrane). stack 100 is provided with at least one gas inlet 101a and at least one gas outlet 101b, both of which stack 100 and the cathode side of the gas-insulating gas supply device. stack 100 also includes at least one fluid inlet 103a and at least one fluid outlet 103b, both of which are stack The setup 200 includes a gaseous CO source 201, a humidifier 203 for humidifying the gaseous CO, an electrochemical stack A power source 220 that provides energy to the 100; stack an anolyte refresher unit 211 for regenerating the anolyte 213 used on the anode side of 100; stack a water separator 208 for removing water from the gaseous product(s) produced by electrolysis of gaseous CO2 on the cathode side of 100; stack Pressurize 100 stackIt further comprises a back pressure regulator 209 for maintaining high pressure (up to 30 bar, preferably up to 20 bar) within 100, as well as a gaseous product outlet 216 opening into a gas phase product vessel (not shown). As CO2 source 201, either a pure gaseous CO2 source or a source that supplies CO2 in the form of a gas mixture may be used. Optionally, the setup 200 comprises: stack a mass flow controller 202 for precisely controlling the mass flow of gaseous CO2 delivered to the cathode side of 100; and stack The CO2 source 201 further includes any suitable pressure gauge 210, 210' for characterizing the pressure prevailing within the CO2 source 201. stack 100 via a suitable pipe 204, while the product outlet 216 is stack 100 via a further pipe 207. As a result, a continuous flow path runs from the CO2 source 201 to the product outlet 216. stack A mass flow controller 202 is preferably inserted in pipe 204 downstream of the CO2 source 201. A humidifier 203 is preferably inserted in pipe 204 downstream of the mass flow controller 202 to humidify the gaseous CO2. stack The air is humidified before entering 100. The humidifier 203 is preferably a temperature-controlled ventilated humidifier, however, any other type of humidifier is also applicable here. Optionally, a pressure gauge 210 is also inserted in the pipe 204, stack The inlet pressure at 100 is continuously monitored. A water separator 208 is connected to pipe 207. stack 100. A back pressure regulator 209 is inserted in pipe 207 downstream of said water separator 208. As water separator 208 and back pressure regulator 209 any kind of water separator and pressure regulator may be used as would be clear to a person skilled in the art. Optionally, a further pressure gauge 210' is inserted in pipe 207. stack 100 and the back pressure regulating valve 209. stack The outlet pressure at 100 is continuously monitored. Thus, pressure gauges 210, 210′ ​​indicate stack The pressure drop through 100 may also be determined.

[0038] stack The anode side of 100 is fluidly connected through its fluid outlet 103b and pipe 205 to the inlet port 211a of an anolyte refresher unit 211. Further, stack The anode side of 100 is fluidly connected through its fluid inlet 103a and pipe 206 to the outlet port 211b of an anolyte refresher unit 211. Thus, a closed continuous flow path is formed. stack At the anode side of 100, an anolyte refresher unit 211 is formed between said anode side and the anolyte 213. Through this closed flow path, the anolyte 213 is pumped, preferably by means of a pump 215 inserted in the pipe 206, through a suitable system of fluid channels formed at the anode side and at the anode. stack The CO2 electrolyser setup 200 and thus the CO2 electrolyser setup 210 are also circulated to and from a refresher unit 211 which refreshes the spoiled anolyte (if necessary) occurring in the electrochemical reaction(s) on the anode side in 100. Furthermore, in order to provide aeration possibilities in said anolyte refresher unit 211, said unit is also equipped with venting means 214, through which excess gases accumulating in the refresher unit 211, separated from the spoiled anolyte 213 during the process of refreshment of the anolyte 213, can leave the unit. stack For optimal operation of 100, the anolyte refresher unit 211 is thermally coupled to suitable tempering means 212 for regulating the temperature, i.e., cooling / heating, of the anolyte 213. To achieve this purpose, any kind of tempering means, i.e., cooler / heater means, may be used, as will be apparent to one skilled in the art.

[0039] stack As far as the power supply of 100 is concerned, the negative terminal of the power supply 220 is stack 100, in particular the cathode contact plate, while the positive pole of the power supply 220 is stackIt is electrically connected to the anode side of 100, particularly the anode side contact plate (described in detail later). The power source 220 can be either the power grid itself or any local power source, i.e. solar, wind, nuclear source. Batteries, either disposable or secondary batteries, can equally be used as the power source 220.

[0040] In operation, carbon dioxide (pure or a gas mixture) is first humidified at a controlled temperature (preferentially ranging from about 20° C. to about 70° C.) and then stack 100 to the cathode side. Here, there is no solution feed to the cathode. If only humidified CO2 gas is fed to the cathode side, the reactant concentration remains very high on the catalyst, so high reaction rates (currents) can be achieved. Furthermore, since there is no solution feed, the reactants are not washed away unreacted by this stream. The reactant types are stack This modification in terms of the type of feed represents a significant difference compared to most prior art solutions, as it has a significant and complex effect on performance. In the presented CO electrolyser setup 200, only gas phase products are stack It is formed in the electrolysis reaction that occurs at 100. stack Depending on the catalyst used in 100 and the CO2 electrolysis reaction applied (see Table 1), various products can be obtained, of which (i) synthesis gas (a CO / H2 mixture with a controlled composition) and (ii) ethylene are mentioned here as examples. The gaseous products that form in the cathode section, i.e. in the system of channels made in the cathode side building blocks (described later), are stack The anolyte 213 (adopted as an aqueous solution, the type of which depends on the type of separator 102 used, i.e. the ion exchange membrane applied) is directly and continuously introduced into a water separator 208 where the water is removed. stack The anolyte 213 is then pumped to the anode side of the anode component 100 by a pump 215. The anolyte 213 is then pumped through a system of channels created in the anode component. stack 100 and collects the gaseous oxygen formed in the electrolysis reaction of CO2 along its path. stack When leaving 100, stack Before being recycled to 100, the oxygen content in the anolyte 213 is released into an anolyte refresher unit 211 and then discharged through the vent means 214. Notably, other value-added anode processes (other than water oxidation, e.g. chlorine formation or alcohol oxidation) can be coupled to the CO2 conversion, as will be apparent to those skilled in the art, and can be implemented in the setup 200 / stack The structure of 100 is not limited to hydroxylation at all. Furthermore, during operation of the setup 200, stack The pressure within 100 is continuously controlled by the back pressure regulator valve 209. Thus, in contrast to most prior art solutions, the electrolyser stack 100 actually operates under a continuous pressure differential.

[0041] FIG. 2A shows the CO2 electrolyzer shown in FIG. stack 100 / A single exemplary PEM electrolyzer that can be used in setup 200 cell FIG. 2B is a schematic cross-sectional view of the BB line shown in FIG. 2A. cell 1 is an enlarged view of a portion of the cell comprises a PEM, in particular an ion exchange membrane 7, 102, which is held in place by spacer elements 9(a, b) arranged along the peripheral edge portions of said membrane 7 on either side (i.e., on the cathode and anode sides). The membrane 7 functions as a separator element, which is cell The cathode 101 and anode 103 (i.e. cathode side and anode side) of the cathode 101 are separated from each other. On the cathode side, adjacent to and arranged in direct contact with the membrane 7, there is a (cathode) catalyst layer 6b. On top of the catalyst layer 6b, on its surface remote from the membrane 7, a gas diffusion layer 6a is arranged in direct contact with said catalyst layer 6b. On top of this gas diffusion layer 6a, a plate 5 of the cathode current collector is arranged in direct contact with said gas diffusion layer 6a.

[0042] Here, the membrane 7 is an anion exchange membrane, available for example under the trade names Fumasep, Selemion and Sustanion, to name just a few, which in operation exchanges hydroxide ions (OH - The movement of electrons (ions, charges, and therefore current) cell between the cathode and anode sides through its bulk, while water (H2O) diffusion through it from the anode side to the cathode side occurs on the cathode side in the electroreduction of CO2. In this case, since electrons are not transported through the membrane 7, the membrane 7 is actually cell It serves as an electrical insulating layer between the cathode and anode sides of the cation exchange membrane 7. As will be clear to those skilled in the art, depending on the electrolytic reaction carried out on the cathode side, cation exchange membranes, for example available under the trade names Nafion and Aquivion, or further bipolar membranes (for example Fumasep FBM) can equally be employed as membrane 7.

[0043] On the one hand, the cathode current collector 5 serves as a current distribution element, i.e. it distributes the current received from an external power source evenly onto the cathode side gas diffusion layer 6a through the cathode side contact plate (described below), while on the other hand it provides an appropriate space for compression of said cathode side gas diffusion layer 6a. The cathode current collector 5 comprises a system of in-plane channels 5″ of height M formed on / in the surface of the cathode current collector 5 facing the membrane 7, said system of channels 5″ corresponding to various geometrical patterns (see for example FIG. 9 ). The patterning of the channels 5″ allows an even distribution of gaseous CO2 on the cathode side gas diffusion layer 6a. The cathode current collector 5 also comprises inlets and inlets in the form of through openings for supplying gaseous CO2 to the gas diffusion layer 6a. cell At the cathode side, an outlet is provided for discharging gaseous products that form in the electrolysis reaction (reduction) of CO2.

[0044] The cathode-side gas diffusion layer 6a, in operation, allows the transport of CO2 to the cathode catalyst layer 6b in contact with the membrane 7, where the reduction reaction of gaseous CO2 takes place, thus forming the desired products. The gas diffusion layer 6a also serves to reduce the amount of said gaseous products (in the form of a mixture that also contains a certain amount of unconverted CO2) cell The cathode side gas diffusion layer 6a can be any of carbon cloth, carbon felt and carbon film, preferably modified with a microporous layer, as known to those skilled in the art, to provide effective transport properties. As the cathode catalyst 6b, multiple catalysts can be used, in which case the applied cathode catalysts are preferably Ag / C and Cu / C catalysts. The gas diffusion layer 6a and the cathode catalyst layer 6b have a total thickness H, as shown in FIG. 2B, which represents the cathode compartment spacing.

[0045] Now, on the anode side, adjacent to the membrane 7 and arranged in direct contact therewith is an anode catalyst layer 8b, in which IrO x , RuO x , NiO x , and TiO x is a highly preferred anode catalyst. On the anode catalyst layer 8b, on its surface remote from the membrane 7, an anode-side gas diffusion layer 8a is arranged in direct contact with said anode catalyst layer 8b. Said anode-side gas diffusion layer 8a is formed of a layer of titanium-frit (Ti-frit) in the form of pressed Ti powders of different average particle sizes (preferably in the range of 50-200 μm) or a layer of nickel-frit (Ni-frit) in the form of pressed Ni powders of different average particle sizes (preferably in the range of 50-200 μm), titanium-mesh (Ti-mesh) or nickel-mesh (Ni-mesh), both preferably with wire thickness and pore size in the range of 50-200 μm, to name a few. On the anode-side gas diffusion layer 8a, a plate 10 of an anode current collector is arranged in direct contact with said gas diffusion layer 8a. The anode current collector 10 also comprises a system of channels 5' formed on the surface of the anode current collector 10 facing the membrane 7.

[0046] On the one hand, the anode current collector 10 functions as a current distribution element, i.e., it distributes the current received from an external power source evenly over the anode side gas diffusion layer 8a through the anode side contact plate (described below), while providing an appropriate space for compression of the anode side gas diffusion layer 8a. The anode current collector 10 also has inlets, in the form of through openings, for supplying liquid anolyte to the anode side gas diffusion layer 8a and for the electrolysis reaction (oxidation) of the anolyte occurring on the anode side. cell An outlet is provided for discharging the mixture of liquid anolyte and anode products (eg, gaseous O 2 if the anolyte also contains water) emerging at the anode side of the reactor.

[0047] As will be apparent to those skilled in the art, the cathode side gas diffusion layer 6a, the cathode catalyst layer 6b, the membrane 7, the anode catalyst layer 8b and the anode side gas diffusion layer 8a can be combined into a single unit, i.e., a membrane / electrode assembly, and can be applied in the form of said assembly, which can be arranged between a cathode current collector 5 and an anode current collector 10 (both of which are in electrical contact and gas / fluid communication therewith), and the assembly can be suitably positioned by anode side spacer elements 9a, 9b to form a modular electrolyzer. cell is constructed. Here, the electrolytic cell thus obtained, shown in FIG. cell is essentially a zero gap electrolytic cell. cell and, as described below, this also corresponds to a modular multi- cell CO2 electrolyzer stack It should also be noted that the 100" can be used to construct a

[0048] Figures 3 and 4 show more than one electrolytic cell. cell An exemplary multi-module cell electrolytic cell stack In particular, FIGS. 3A and 3B show electrolytic cells stack100' shows top and bottom perspective views of three electrolyzers used to convert gaseous CO2 to gaseous products by electrolysis at high pressure and high conversion rates. cell FIG. 4 shows a multi- cell electrolytic cell stack This is an exploded view of a part of the 100" cell 40 (n is a positive integer), cell 1 electrolytic cell in 40 cell However, due to practical considerations, humans may choose a number n ranging from at least 1 to as much as 10 or more, and in particular cell The number n of electrolytic cells stack Per 100", preferably between 2 and 7, more preferably between 3 and 6, and most preferably 3, or 4, or 5, or 6.

[0049] As can be seen in Figures 3A, 3B and 4, the electrolytic cell stack 100' and 100" have modular structures, stack The components used to construct 100', 100" are provided in the form of plate-like elements of different functions. The plate-like elements can have any planar shape, and in the exemplary embodiment shown in Figs. 3A, 3B and 4, the elements are essentially circular. Furthermore, the components stack To aid in rapid assembly and / or reassembly of the plate-like components 100', 100", each is provided with an assembly aid recess 52 formed in its peripheral edge. The assembly aid recess 52 thus aids in determining how the components are to be properly assembled and / or reassembled. stack 10, the recesses 52 are aligned in the correct alignment / orientation of the components.

[0050] Assembling the components stack Then, we get stack are the individual electrolytic cells cellare arranged along the longitudinal direction. Here, and hereinafter, the term "longitudinal direction" refers to a direction that is essentially perpendicular to the surface of the plate-like component. Thus, as shown in FIGS. 3A, 3B, and 4, the plate-like component is provided with a plurality of through-holes along the longitudinal direction. Some of the holes function as opening holes 1a, and the components are assembled stack to receive the screw 1 having a shrink tube and a pad used to make 100’, 100”, and then the components are connected in a sealed manner by a screw-nut 14 having a pad that is screwed onto the screw 1 inserted into each individual opening hole 1a. The remaining part of the holes formed in the plate-like component, which is configured to be sealed by specific channel sealing means (detailed below) that can be properly aligned with each other and arranged around each of the holes and between the plate-like components, stack functions to form the longitudinal flow-through portions of the cathode and anode side transport channel structures within 100’, 100”. In particular, on the cathode side, one of the holes functions as a gas inlet 21 for introducing gaseous CO2 into stack an electrolyzer assembled in either a series or parallel (or mixed) configuration from the perspective of CO2 supply and transport within cell 40, while two other of the holes (i) function as a fluid inlet 23 for introducing liquid anode solution into an electrolyzer cell assembled in a series / parallel configuration and (ii) function as a fluid outlet 24 for discharging the deteriorated anode solution together with the gaseous anode product (e.g., O2) formed in the individual cell 40 during the anodic electrolysis reaction(s). Now, on the anode side, one of the holes functions as a gas outlet 22 for discharging the overly supplied unreacted CO2 together with the gaseous cathode product formed in cell 40 during the cathodic electrolysis of CO2.

[0051] Next, regarding FIG. 4, the multi cell CO2 electrolyzer according to the present invention stack100" is used to decompose gaseous CO2 by electrolysis and thus produce various gaseous products depending on the applied catalyst and anolyte. To this end, stack 100″ denotes a certain number n of electrolytic cells arranged adjacent to each other and in closed fluid / gas communication through the longitudinal portions of the cathode and anode side transport channel structures. cell 40. Furthermore, the electrolytic cell cell 40, each other, and stack 100″ electrical terminals, i.e., in series with the cathode and anode contact plates 4, 11. Thus, stack 100″ is a cross-sectional view of an interconnected intermediate unit sandwiched between a cathode end unit 26 and an anode end unit 27 arranged at the opposite end of the series along the longitudinal direction. cell A series of electrolytic cells consisting of cell Includes 40.

[0052] The cathode end unit 26 comprises a series of electrolytic cells. cell 40 stack The cathode end unit 26 is closed at the cathode side of the series at 100". The inner surface of the cathode end unit 26 is cell 40, whereas the outer surface of the cathode end unit 26 is in direct contact with the cathode contact plate 4, while the outer surface of the cathode end unit 26 is in fact exposed to the environment. The cathode end unit 26 has a modular structure itself, which comprises a cathode contact plate 4 with an associated inner surface, a cathode insulator 3 arranged on said cathode contact plate 4, and a cathode end plate 2 with an outer surface arranged on the cathode insulator 3. The cathode end plate 2 is respectively provided with: stack Openings in gas / fluid communication with the 100″ cathode and / or anode transport channel structures are provided through respective openings formed in the insulator 3 and contact plate 4 in proper alignment with the relevant openings, i.e., gas inlet 21 for CO2 supply, fluid inlet 23 for anolyte supply, and fluid outlet 24 for spoiled anolyte (and anode products) exhaust. stackIn the assembled condition of 100", the openings formed in the cathode end unit 26 in register with one another form continuous longitudinal closed flow passages, each of which is connected to a first electrolytic cell. cell 40. Here, sealing is performed between the end plate 2 and the insulating material 3, between the insulating material 3 and the contact plate 4, and between the contact plate 4 and the first cell This is achieved by appropriately sized sealing elements (in the form of O-rings 15, 16, 17, preferably made of a corrosion resistant plastic material, e.g. Viton®) arranged around each opening between the cathode end plate 2 and the cathode end plate 3, as mechanical strengthening elements, by through screws 1. stack The cathode side insulation 3 acts as an electrical insulator between the end plate 2 and the cathode side contact plate 4. The cathode side insulation 3 also houses the cathode side pressure chamber, which is stack When 100" is applied at the start of its operation, stack 100″ toward the cathode end plate 2. The pressure chamber is formed as a hollow cavity in the bulk of the cathode insulation 3, stack When the cathode terminal unit 100" is assembled, it extends over a portion of the cathode end plate 2. In such a case, the cathode pressure chamber is sealed by an O-ring 15 arranged in a circular groove around said cavity in the cathode insulation 3, between the insulation 3 and the end plate 2. Furthermore, the cathode contact plate 4 serves as an electrical connection to an external power source, and at the same time, transmits the current received from said power source through the inner surface of the cathode terminal unit 26 to a series of intermediate cell The very first in 40 cell The cathode contact plate 4 also functions as a current distribution element that distributes the gaseous CO2 evenly over the outermost surface of the cathode. stack 100" first electrolytic cell cell 40, and the liquid anolyte and spoiled anolyte, respectively. stack 100" first electrolytic cell cell 40. Serves for introduction and evacuation into and from the bloodstream.

[0053] The anode side terminal unit 27 is stack A series of electrolytic cells on the anode side of 100 cell 40 is closed. The inner surface of the anode end unit 27 is the last, i.e., nth, cell 40, whereas the outer surface of the anode end unit 27 is in fact exposed to the environment. The anode end unit 27 has a modular structure itself, which comprises an anode contact plate 11 with an associated inner surface, an anode insulator 12 arranged on said anode contact plate 11, and an anode end plate 13 with an outer surface arranged on the anode insulator 12. The anode end plate 13 has stack Openings in gas communication with the 100" cathode transport channel structure are provided through respective openings formed in the anode side insulation 12 and anode side contact plate 11 in proper alignment with the openings in question, i.e., gas outlets 22 for CO2 and cathode product exhaust. stack In the assembled condition of 100", the openings formed in the anode end unit 27 in register with one another form a continuous longitudinal closed flow passage which is connected to the final electrolytic cell. cell 40, where a sealing, preferably in the form of an O-ring, is provided in said last cell This is achieved by suitably sized sealing elements arranged around the openings between the anode contact plate 11, the anode contact plate 11 and the anode insulator 12, and the anode insulator 12 and the anode end plate 13, with associated O-rings similar / equivalent to the O-rings employed in the cathode terminal unit 26. Here, the anode contact plate 11 serves as the electrical connection to an external power source and at the same time transmits the current received from said power source through the inner surface of the anode terminal unit 27 to a series of intermediate cell The Real Last of 40 cell The anode contact plate 11 also functions as a current distribution element that distributes the gaseous CO2 mixed with the electrolysis products evenly over the outermost surface of the anode. stack The last electrolytic cell of 100 cellIt is useful for the discharge from 40. The anode-side insulator 12 functions as electrical insulation between the anode-side contact plate 11 and the anode-side end plate 13. The anode-side insulator 12 also houses the anode-side pressure chamber, which stack prevents possible movement towards the anode-side end plate 13 of the internal components of 100 when 100 is pressurized at the start of its operation. stack The pressure chamber is formed as a hollow cavity within the bulk of the anode-side insulator 12 and stack extends over a predetermined portion of the anode-side end plate 13 when 100 is assembled. In such a case, the anode-side pressure chamber is sealed by an O-ring 15 arranged between the insulator 12 and the anode-side end plate 13 within a circular groove around the cavity within the anode-side insulator 12. Further, the anode-side end plate 13, as a mechanical strengthening element, has a pad screwed onto a screw 1 inserted through the entire structure of 100 from the cathode-side end plate 2 at the opening hole 1a by a screw-nut 14, stack which functions to enhance the pressure resistance of 100. In harmony with convention, the cathode-side contact plate 4 and the anode-side contact plate 11 are electrically connected to the negative and positive electrodes of an external power source, respectively. stack

[0054] Hereinafter, FIGS. 5, 5A and 5B will be described. These show a bipolar plate assembly 40' consisting of two components in a bottom view, a cross-sectional view taken along line A-A and a cross-sectional view taken along line B-B, respectively. The first component 40a of the assembly 40' (i.e., the anode current collector 10 in a single cell ) and the second component 40b of the assembly 40' (i.e., the cathode current collector 5(a, b, c, d) in a single cell ) are provided on opposite surfaces together with certain elements having cathode and anode-side transport channel structures. In particular, the first component 40a has cellInlet / outlet ports are provided for the cathode and anode side flow path systems in the bipolar plate assembly 40'. The ports are: for cathode side gas supply and transport (i.e., CO2, the desired product) in the bipolar plate assembly 40'; cell Inlet gas transport channel 41 and cell An outlet gas transport channel 42, as well as a gas supply and transport channel 43 for fluid supply and transport (i.e., anolyte, spoiled anolyte and anode products, e.g., gaseous O2) on the anode side of the bipolar plate assembly 40'. cell anolyte inlet channel 48; cell anolyte outlet channel 49; cell An anolyte transport channel 43, and cell Anolyte and anode product transport channels 44. The first component 40a includes: stack On / in its side facing the cathode end unit, an in-plane system of fluid channels 5' of a certain geometry is further provided. Said ports lead from said side to the opposite side of the first component 40b, where each of said ports opens into an individual cavity that completely surrounds it, i.e. cavities 33a, 33b, 33c, 33d. Said cavities and ports provide fluid communication with individual longitudinal fluid channels 41', 42', 43', 44' formed in the second component 40b. Said second component 40b also includes a gas supply and transport (i.e. CO2, desired product) on the cathode side of the bipolar plate assembly 40'. cell Gas inlet channel 46 and cell A gas outlet channel 47 is provided, as well as an in-plane system of gas flow paths 5 ″ of a certain geometric shape (see FIG. 9 ). The cavity is equipped with suitable sealing members, in particular O-rings 16, 17, 17′, 19 made of a corrosion-resistant plastic material (for example Viton®), stack When assembled, the flow path is sealed and stack The pressure spreading within is maintained.

[0055] The first and second components 40a, 40b of the assembly 40' are electrically conductive. stack It is made of the same conductive compounds as other parts, such as titanium, stainless steel, different alloys and composite materials. The ports and cavities are formed by machining, especially CNC - milling.

[0056] As is apparent from Figure 4, the CO₂ electrolyzer according to the present invention stack After assembling the "100", the cathode - side and anode - side end units 26, 27 sandwich n actually identical intermediate electrolyzers cell 40, and the electrolyzers cell 40 are connected to each other (i) stack In series from the perspective of power (current) management of the "100", (ii) stack In parallel from the perspective of anode liquid supply and transport within the "100", and (iii) stack In series or in parallel, or in a mixed mode, from the perspective of CO₂ supply and transport within the "100". Each cell 40 is constructed from a bipolar membrane assembly 40' consisting of two components (see Figures 5A and 5B). In particular, each cell 40 includes the first (anode) component 40a of the i - th bipolar membrane assembly 40', the second (cathode) component 40b of the adjacent, i.e., (i - 1)-th bipolar membrane assembly 40' (where 1 < i < n, integer), the membrane / electrode assembly described above arranged between the first and second components 40a, 40b, and the anode - side spacer elements 9a, 9b inserted between the first and second components 40a, 40b of the bipolar membrane assembly 40' in its peripheral region. Feature (i) is stack The result of electrical contact between subsequent cell 40 within the "100". Feature (ii) is the physical structure, i.e., the number of longitudinal channels provided in the anode - side spacer elements 9a, 9b for gas transport on the cathode side, and the orientation in which certain spacer elements 9a, 9b are stack Actually arranged within the "100". In particular, as shown in Figure 10A, a single longitudinal channel 36 forms stack A series gas flow path on the cathode side of the "100" for two adjacent cellprovided in the spacer element 9a used when connecting cell The individual configurations of are shown in an exploded view in FIG. 12A. Moreover, as shown in FIG. 10B, two longitudinal channels 36 are stack Two adjacent gas flow passages extending in parallel on the cathode side of 100" cell is provided in spacer element 9b for use when connecting the two, where longitudinal channels 36 are formed at diametrically opposed positions of spacer element 9b. cell The individual configurations are shown in exploded view in FIG. 12B.

[0057] In the following, the cathode side gas management and the anode side fluid management are divided into three individual cell 40 or multi-plate assembly including bipolar plate assembly 40' cell electrolytic cell stack 100" in more detail. In particular, FIG. 6 shows the 3- cell electrolytic cell stack 100' is shown in cross section taken along line AA shown in FIG. 3A; stack The gas flow paths are shown in grey, where: stack 100' is stack From the perspective of CO2 supply and transportation within 100', each cell of 40 cell The gas flow paths are assembled in a parallel configuration. cell electrolytic cell stack 100' is shown in a cross-sectional view taken along line AA shown in FIG. 3A; stack The gas flow paths are again shown in grey, where: stack 100' is stack From the perspective of CO2 supply and transportation within 100', each cell of 40 cell Additionally, FIG. 8 shows a 3- cell electrolytic cell stack 100' is shown in a cross-sectional view taken along line BB shown in FIG. 3A; stack The fluid flow paths of are shown in grey, where: stack 100' is stackFrom the perspective of CO2 supply and transportation within 100', each cell Assembled in any of 40 series and parallel configurations, cell The fluid flow paths are aligned; stack In terms of anolyte supply and transport within 100', the parallel configuration stack The fluid flow path is formed.

[0058] FIG. 6 shows a schematic diagram of a cathode pressure chamber 31 formed in the cathode end unit, in particular in the cathode insulation 3, from the gas inlet 21 to the gas outlet 22, and then in the cathode current collector. cell 9 ) formed in the surface of the cathode current collector facing the cathode side gas diffusion layer. In cell 40 The first electrolytic cell is arranged as follows: cell 40 to cell A continuous gas inlet 46 extends through the gas inlet stack 1 shows the gas flow path. stack The gas flow passages are then formed between a cathode-side current collector and a cathode-side gas diffusion layer (which are in partial contact with each other). cell Within 40 cell The gas passage further extends to the first cell 40 is gas-connected to the sealed cavity 33b. cell The gas exits through gas outlet 47 and the cavity 33b is formed in the surface of the anode current collector. stack The gas flow path then extends from said cavity 33b through the outlet gas transport channel 35, then through holes formed in the anode side contact plate 11 and the anode side insulation 12 into the anode side termination unit, in particular into the anode side pressure chamber 32 formed in the anode side insulation 12, and then from said anode side pressure chamber 32 to the gas outlet 22. Here, the outlet gas transport channel 35 is formed in the cathode current collector. cellThe outlet gas transport channel 42' (see FIG. 9), the internal gas transport channel 36 of the anode spacer element 9b (see FIG. 10B) and the anode current collector are formed in cell It is formed by an outlet gas transport channel 42 (see, for example, FIG. 11A).

[0059] Additionally, CO2 may be added to the second and any subsequent cell To supply 40 stack The flow paths are from the cathode pressure chamber 31 through the inlet gas transport channel 34 to the individual cell 40 anode current collectors, each of which extends into a sealed cavity 33a formed in said surface of said anode current collector 40, cell of 40 cell 1 and 2. The gas inlet 46 is connected to the gas inlet 46. Thus, in operation, cell 40 are all in gas communication with the inlet gas transport channel 34, which stack 100'. The inlet gas transport channel 34 is formed in the cathode current collector. cell the inlet gas transport channel 41, the further internal gas transport channel 36 of the anode spacer element 9b and cell It is formed by an inlet gas channel 41 which terminates at an inlet gas transport channel end 34a, ie, a dead furrow.

[0060] FIG. 7 shows a continuous gas inlet 21 extending to a gas outlet 22. stack The gas flow path of the multi- cell electrolytic cell stack 100′, when assembled, is advantageous in that (i) the anode spacer member 9a has only a single internal gas transport channel 36 (instead of two), and (ii) the anode spacer member 9a is adjacent cell 1, due to the fact that the spacer elements 9a are arranged in an orientation that is rotated by exactly 180° about an axis perpendicular to their centers. stack The flow paths are connected in series as a result of the division of the inlet gas transport channel 34 and the outlet gas transport channel 35. cellThis results in a flow path for the flow channel (see FIG. 6).

[0061] FIG. 8 shows a flow path from the fluid inlet 23 to the fluid outlet 24, through a channel 43' in the cathode current collector, through a channel 38 in the spacer element, and into the electrolytic cell. cell through the channel 43 in the anode current collector, through the continuous inlet flow transport channel formed, and then cell Through closed cavity 33c in flow communication with fluid inlet 48, then through flow pattern 5', through channel 49 into closed cavity 33d, then through channel 44 in the anode current collector, through channel 39 in the spacer element and into the electrolytic cell. cell A continuous outlet flow channel extending from the cavity 33d in fluid communication with the continuous outlet flow channel formed through the channel 44' in the cathode current collector of the stack 1 shows the fluid flow path.

[0062] In the following, a single electrolytic cell constructed from a two-component bipolar plate assembly 40' will be described. cell 40, e.g., decomposed in Fig. 4 cell The structural components of what is shown as are described in more detail with reference to Figures 9 to 11.

[0063] In particular, FIG. 9 shows four possible embodiments of cathode current collectors 5a, 5b, 5c, 5d (which form the second component 40b of the two-component bipolar plate assembly used), each of which is provided with a certain in-plane flow channel configuration or flow pattern 5″. The flow pattern 5″ is cell This is an essential part of achieving uniform CO2 supply to and efficient product collection from the cathode side of the reactor, where the CO2 supply is cell Gas inlet occurs through a gas inlet channel 46, while product collection occurs through a gas inlet channel 46, which also extends longitudinally. cell9, gaseous CO2 is fed in the center, i.e. through the gas outlet channel 47. Between said inlet channel 46 and outlet channel 47, gaseous CO2 is transported and continuously participates in the cathodic electrolysis reaction and thus converted into gaseous products in the grooves 45 of the continuous flow pattern 5″, which are in contact with the membrane / electrode assembly (not shown). As can be seen in FIG. 9, in the three exemplary flow designs, i.e. the flow designs of FIGS. 5(a) to 5(c), which correspond to the labyrinth flow pattern, the offset circle flow pattern and the radial double helix flow pattern, respectively ... cell The gas inlet channel 46 is located at the center of the cathode current collector and collected over the outer ring, i.e. cell The gas outlet channels 47 are arranged around the periphery of the cathode current collector. Figure 5(d) shows a further such flow design, where CO2 is fed on the outer periphery of the cathode current collector and collected after passing through a double helix pattern, e.g., at the diametrically opposite position of the cathode current collector, i.e. cell Both gas inlet and outlet channels 46, 47 are located in the peripheral region of the cathode current collector. Surprisingly, it was found that, unlike fuel cells, the best performing flow patterns were always those in which CO2 was supplied at the center of the flow pattern.

[0064] Here, cathode current collectors 5a, 5b, 5c, 5d of different flow patterns 5″ are arranged together with the same anode current collector 10. Multi-layer stack It should be noted that for use in, or in other words for use of a second component 40b of a two-component bipolar plate 40' with a different flow pattern 5" of the single-type first component 40a (i.e. provided with a unique flow pattern 5'), the inlet gas transport channel 41 is specifically formed. In particular, the shape of said inlet gas transport channel 41 is circular on the side of the second component 40b having the flow pattern 5", whereas on the opposite side of the second component 40b, irrespective of the fact that it is formed in the center or in the peripheral area of ​​the second component 40b. cell It has a narrow elongated shape to cover the gas inlet channel 46 .

[0065] 10A and 10B show multiple configurations for achieving either series or parallel cathode gas flow channel configurations, respectively. cell electrolytic cell stack All 100' and 100" electrolytic cells cell At 40, a possible embodiment of the anode side spacer elements 9a, 9b arranged between the cathode current collector and the anode current collector is shown. The two types of anode side spacer elements 9a, 9b are practically identical, but differ in the number of longitudinally extending internal gas transport channels 36. With this unique choice of design, the anode side spacer elements are stack In the gas flow path of cell The spacer elements are configured to function as a means for selectively choosing the manner in which the flow channels are connected to each other. The anode side spacer elements 9a, 9b are made of an electrical insulator, preferably plastic or Teflon. Thus, the anode side spacer elements 9a, 9b can be easily and cheaply produced automatically, even on an industrial scale.

[0066] FIG. 11 shows a CO2 electrolysis cell according to the present invention. stack FIG. 11A illustrates an anode current collector 10 (forming a first component 40a of a two-component bipolar plate assembly) for use in a semiconductor laser, FIG. 11A being a top view, while FIG. 11B is a bottom view of the anode current collector 10; stack 1 highlights the cavities 33a, 33b, 33c, 33d provided for establishing a tight gas / fluid connection for the gas / fluid management of the device as well as for accommodating the required sealing elements, i.e. various O-rings.

[0067] Finally, FIGS. 12A and 12B show exploded views of a multi-cell gas turbine assembled in series and parallel cathode-side gas flow configurations, respectively. cell electrolytic cell stack Single cell12A and 12B also show the advantages of the applied modular structure. In particular, by replacing an anode spacer element 9a having only a single internal gas transport channel 36 with an anode spacer element 9b including two internal gas transport channels 36, the associated cell The flow configuration of 40 can be easily modified from series to parallel and vice versa. stack of cell Then, cell Disassemble either one of the above into components and replace the anode spacer element(s) with the anode spacer element(s) required for the desired cathode side gas flow configuration, and then cell is reassembled from the components, and then stack of cell Reassembly from the original allows for multiple gas flow management options cell electrolytic cell stack Therefore, according to the present invention, multilayer electrolytic cell stack can be easily and quickly adapted to operational requirements, practically in the field.

[0068] In the following, the invention and its advantages are presented in one cell Or three cell (in the latter case they are connected in series / parallel) stack Further discussion is based on the experimental measurements specifically performed above.

[0069] As already discussed, the CO2 electrolyser according to the present invention stack is at least one, preferably more than one cell That is, the cores, which perform the electrolysis of CO2, are electrically connected in series and stack From the gas management point of view, the individual electrolysers connected in series or parallel configuration cell Constructed from stack Used to build cellIndeed, the number can be up to 10 or more, preferably ranging from 2 to 7, more preferably from 3 to 6, and most preferably 3, or 4, or 5, or 6. EXAMPLES

[0070] <Example 1 - Operation> In this example, a 3-phase cascade was assembled in a series configuration and then in a parallel configuration (from the perspective of cathode side gas management). Cell Stack Some of the operating characteristics of Cell stacks (i.e. single cells) Compare with the one in the previous section.

[0071] FIG. 13 illustrates a gas turbine engine according to the present invention assembled in either a series or parallel gas flow configuration. stack The individual electrolytic cells used in the possible embodiments of cell The effect of increasing the number of CO2 feed rates is shown in plot (a). cell and 3- cell Series connection stack Achieved for ΔU=-2.75V / cell In plot (b), the CO2 conversion during electrolysis is plotted. cell One with a standardized gas supply cell Or three cell It consists of stack The CO2 conversion during electrolysis is shown at different cell voltages achieved for T = 50 °C. A series of measurements was performed with 1 M KOH anolyte (1.5 dm 3 min -1 The cathode catalyst layer was fed at a rate of 3 mg cm. -2 Ag was fixed onto Ziglarset 39BC carbon paper by spray coating. For the anode catalyst, 1 mg cm -2 Ir black was immobilized on a porous titanium frit. Both catalyst layers contained 15 wt% Sustanion ionomer. The cathode compartment was purged with humidified CO2 (in room temperature deionized water). In addition, the CO2 flow rate was 8.3 cm3 for the measurements shown in (b). 3 cm -2 min-1 was set to.

[0072] As is evident from plot (a), the three electrolytic cells cell When are connected in series (1- Cell Stack under the same conditions): CO2 conversion is improved This effect is more pronounced at higher flow rates, and Approximately 40% conversion is achieved.

[0073] As is evident from plot (b), the three electrolytic cells cell When are connected in parallel (1- Cell Stack under the same conditions): -Without changing the operating characteristics cell It is possible to increase the number of · stack Inside the CO2 stream is split equally as well as ·Conversion and CO partial current is 3- cell The morphology is similar, providing clear evidence of the scalability of the process.

[0074] FIG. 14 shows a 3-CO mixture according to the present invention used for synthesis gas (H2 / CO mixture over Ag catalyst) or hydrocarbon (CH4 and C2H4 over Cu catalyst) formation. cell CO2 electrolyzer stack Current density vs. operating cell -Voltage. The curves are measured by linear sweep voltammetry (LSV), ν=10mVs -1 A series of measurements was recorded using a cathodic gas diffusion electrode (GDE) containing different catalysts at a sweep rate. The measurements were performed at T = 50 °C. 1 M KOH anolyte was continuously introduced into the anode compartment (approximately 9 cm 3 cm -2 min -1 The experiment was carried out by supplying CO2 (at a feed rate of u = 2.5 cm) to the cathode compartment, while the cathode compartment was filled with humidified CO2 (in room temperature deionized water) at u = 2.5 cm 3 cm -2 min -1 The flow rate of the cathode catalyst layer was 1 mg cm.-2 Ag was fixed onto Ziglarset 39BC carbon paper by spray coating. Cu-containing GDE was formed by electrodeposition. For the anode catalyst layer, 1 mg cm -2 Ir black was immobilized on a porous titanium frit. Both catalyst layers contained 15 wt% Sustanion ionomer. stack were equipped with spacer elements having a thickness of 300 μm.

[0075] cell The electrochemistry of demonstrates low voltage requirements. Enhanced under pressure stack For excellent electrical coupling between the various components of stack The operating voltage of is rather low (2.5 to 3.0 V). This leads to good energy efficiency (40-50%). Syngas (H2 / CO mixture) formation was demonstrated over Ag / C catalyst, while ethylene production was demonstrated over Cu / C catalyst.

[0076] Figure 15 shows the electrolytic cell. stack The chronoamperometric curves shown demonstrate the stable operation of the 3- cell CO2 electrolyzer stack About 1 mg cm fixed by spray coating on Ziglar Set 39BC carbon paper -2 Using a GDE with a cathode containing Ag catalyst, ΔU = -3 V / cell For the anode, 1 mg cm -2 Ir black was immobilized on a porous titanium frit. Both catalyst layers contained 15 wt% Sustanion ionomer. stack The measurement was performed at T = 50 °C. 1 M KOH anolyte was continuously added to the anode compartment (approximately 9 cm 3 cm -2 min -1 The experiment was carried out by supplying CO2 (at a feed rate of u = 2.5 cm) to the cathode compartment while filling the cathode compartment with humidified CO2 (in room temperature deionized water) at u = 2.5 cm 3 cm -2 min -1 The mixture was purged at a flow rate of 1000 rpm.

[0077] FIG. 16 shows electrolytic cells with different catalysts. stack Figure 1 presents the formation of different gaseous CO2-reduction products produced using spray-coated, 3 mg cm -2 Using Ag-catalyst-containing GDE [plot (a)] and Cu-catalyst-containing GDE formed by electrodeposition of copper nanocubes on Ziglarset 39BC carbon paper [plot (b)], the 3- cell CO2 electrolyzer stack ΔU=-2.75V / cell Shown are gas chromatograms recorded during chronoamperometric measurements at 1 mg cm for the anode. -2 Ir black was immobilized on a porous titanium frit. The Ag-containing GDE and anode catalyst layers contained 15 wt% Sustanion ionomer. stack The anode compartment was fitted with a spacer element of 270 μm thickness. The measurements were carried out at T=50° C. by continuously feeding 1 M KOH anolyte into the anode compartment (approximately 9 cm 3 cm -2 min -1 while the cathode compartment was humidified (in room temperature deionized water) with CO at u = 2.5 cm 3 cm -2 min -1 The mixture was purged at a flow rate of 1000 rpm.

[0078] Example 2 - Voltage-dependent product distribution In this embodiment, the composition of the generated synthesis gas (H2 / CO ratio) is stack This proves that the voltage can be easily adjusted. stack The higher the voltage, the more H2 is produced.

[0079] FIG. 17 shows the results of different stack At voltage, 3 mg cm fixed by spray coating on Ziglar Set 39BC carbon paper -2Partial current densities (left ordinate) and partial current density ratios (right ordinate) for CO and H2 formation using Ag-containing cathode GDEs. For the anode, 1 mg cm -2 Ir black was immobilized on a porous titanium frit. Both catalyst layers contained 15 wt% Sustanion ionomer. stack The anode compartment was fitted with a spacer element of 300 μm thickness. The measurements were performed at T = 50 °C by continuously supplying 1 M KOH anolyte to the anode compartment (approximately 9 cm 3 cm -2 min -1 0.05 cm2) while the cathode compartment was filled with humidified (room temperature deionized water) CO2 at u = 2.5 cm2. 3 cm -2 min -1 The mixture was purged at a flow rate of 1000 rpm.

[0080] Example 3 - Effect of catalyst loading This example demonstrates that the carbon dioxide reduction rate is strongly dependent on the amount of fixed cathode catalyst: the partial current density for CO formation reaches a maximum at intermediate catalyst loadings.

[0081] FIG. 18 shows the partial current density (left ordinate) for H2 and CO formation during electrolysis at ΔU = -2.75 V as well as the CO2 conversion (right ordinate) as a function of the amount of Ag catalyst in the cathode GDE. The Ag cathode catalyst layer was fixed on Ziglarset 39BC carbon paper by spray coating. For the anode, 1 mg cm -2 Ir black was immobilized on a porous titanium frit. Both catalyst layers contained 15 wt% Sustanion ionomer. Measurements were performed at T = 50 °C by continuously feeding 1 M KOH anolyte into the anode compartment (approximately 9 cm 3 cm -2 min -1 0.05 cm2) while the cathode compartment was filled with humidified (room temperature deionized water) CO2 at u = 2.5 cm2. 3 cm -2 min -1 The mixture was purged at a flow rate of 1000 rpm.

[0082] Example 4 - Effect of cathode spacing (GDL compression) This embodiment is a method according to the present invention. stack This provides an additional benefit of the design. By simply changing one plastic element, the compression of the gas diffusion layer (GDL) can be varied. Notably, both product distribution and conversion are affected by this parameter. Importantly, if a different GDL must be used, stack can be quickly and easily fitted to it (unlike the fuel-cell-like setup, where gas-sealing and compression of the GDL is achieved by using a gasket of a given thickness, which must be carefully fitted to the GDE by hand).

[0083] FIG. 19 shows the partial current density (left ordinate) for H2 and CO formation during electrolysis at ΔU=-2.75 V and CO2 conversion (right ordinate) as a function of the applied cathode spacing. For the cathode, 1 mg cm -2 The Ag cathode catalyst layer was fixed on Ziglarset 39BC carbon paper by spray coating. For the anode, 1 mg cm -2 Ir black was immobilized on a porous titanium frit. Both catalyst layers contained 15 wt% Sustanion ionomer. Measurements were performed at T = 50 °C by continuously feeding 1 M KOH anolyte into the anode compartment (approximately 9 cm 3 cm -2 min -1 0.05 cm2) while the cathode compartment was filled with humidified (room temperature deionized water) CO2 at u = 1.25 cm2. 3 cm -2 min -1 The mixture was purged at a flow rate of 1000 rpm.

[0084] Example 5 - Effect of flow patterns applied in the cathode current collector This example shows that the flow pattern design (see FIG. 9) is stack The residence time of CO2 gas in the stackIt is clearly shown that groove depth M (see FIG. 2B) has a significant effect on the performance. Here, the effect of groove depth M (see FIG. 2B) is presented for the flow pattern of FIG. 9(a). According to this example, there exists an optimal groove depth and hence residence time, which ensures high conversion.

[0085] FIG. 20 shows the partial current densities for H2 and CO formation (left ordinate) and CO2 conversion (right ordinate) during electrolysis at ΔU=−2.75 V for an electrolyzer according to the invention. stack The flow rate of the applied flow pattern on the cathode side of the 3 mg cm 2 Cr-Al 2 O 3 ... -2 The Ag cathode catalyst layer was fixed on Ziglarset 39BC carbon paper by spray coating. For the anode, 1 mg cm -2 Ir black was immobilized on a porous titanium frit. Both catalyst layers contained 15 wt% Sustanion ionomer. Measurements were performed at T = 50 °C by continuously feeding 1 M KOH anolyte into the anode compartment (approximately 9 cm 3 cm -2 min -1 0.05 cm2) while the cathode compartment was filled with humidified (room temperature deionized water) CO2 at u = 2.5 cm2. 3 cm -2 min -1 The mixture was purged at a flow rate of 1000 rpm.

[0086] Example 6 - Electrolytic cell stack Effect of carbon dioxide flow rate on This example shows that as the CO2 flow rate increases, the electrolytic cell according to the invention stack The purpose of this study is to prove that the conversion rate (current density) of CO2 increases. At the same time, the relative ratio of converted CO2 to feed rate decreases (hence an optimum value for the CO2 flow rate must be found and used).

[0087] FIG. 21 shows the partial current densities for H2 and CO formation (left ordinate) and CO2 conversion (right ordinate) during electrolysis at ΔU=-2.75 V for an electrolyzer according to the invention. stackThe carbon dioxide flux in the cathode compartment is shown as a function of surface area normalized to the carbon dioxide flux in the cathode compartment of 3 mg cm. Again, for the cathode, -2 The Ag cathode catalyst layer was fixed on Ziglarset 39BC carbon paper by spray coating. For the anode, 1 mg cm -2 Ir black was immobilized on a porous titanium frit. Both catalyst layers contained 15 wt% Sustanion ionomer. Measurements were performed at T = 50 °C by continuously feeding 1 M KOH anolyte into the anode compartment (approximately 9 cm 3 cm -2 min -1 The experiment was carried out at a feed rate of 1000 rpm.

[0088] Example 7 - Anolyte ( stack )Effect of temperature> This example is presented to demonstrate that high reaction rates and selectivities can be achieved at high temperatures, which can be easily controlled by the anolyte temperature. stack The components of are designed to withstand exposure to hot (alkaline) solutions as exemplified in this case.

[0089] FIG. 22 shows the partial current densities for H2 and CO formation (left ordinate) and CO2 conversion (right ordinate) during electrolysis at ΔU=-2.75 V for an electrolyzer according to the invention. stack The temperature of the anolyte (1M KOH) occurring at 3 cm -2 min -1 The cathode compartment was filled with humidified (room temperature deionized water) CO2 at u = 2.5 cm as a function of CO2. 3 cm -2 min -1 Again, for the cathode, 3 mg cm -2 The Ag cathode catalyst layer was fixed on Ziglarset 39BC carbon paper by spray coating. For the anode, 1 mg cm -2 Ir black was immobilized on a porous titanium frit. Both catalyst layers contained 15 wt% Sustanion ionomer.

[0090] Example 8 - Electrolytic cell stack Effect of pressure on In this embodiment, the lower stack At higher voltages, CO2 reduction, on the other hand, is greater. stack The purpose of this study is to prove that at low voltages, water reduction becomes the dominant cathodic process. The crossover between the two processes is shifted to higher current densities by increasing the CO2 pressure, thereby allowing the CO2 electroreduction to proceed at a higher rate. stack The slope of the LSV curve at voltage gradually increases with CO2 pressure. stack To achieve the same current density under the applied pressure, stack A voltage is required. This is stack This is further highlighted by tracing the LSV curves - recorded at different CO2 pressures - at voltage.

[0091] FIG. 23 shows an electrolytic cell according to the present invention. stack During electrolysis carried out at ν=10 mVs -1 We present LSV curves recorded under various CO2 differential pressures ranging from 1 bar to 10 bar at a sweep rate. Again, for the cathode, 3 mg cm -2 The Ag cathode catalyst layer was fixed on Ziglarset 39BC carbon paper by spray coating. For the anode, 1 mg cm -2 The Ir black was fixed onto a porous titanium frit. The measurements were performed at T = 50 °C by continuously supplying 1 M KOH anolyte to the anode compartment (approximately 9 cm 3 cm -2 min -1 ) while the cathode compartment was filled with humidified (room temperature deionized water) CO at u = 12.5 cm 3 cm -2 min -1 The mixture was purged at a flow rate of 1000 rpm.

[0092] Furthermore, FIG. stackThe current density at voltage (plot A) and the partial current density ratio during electrolysis at ΔU = -2.75 V (plot B) are shown for the electrolyzer when operated continuously. stack As a function of the CO2 pressure differential prevailing at 3 mg cm -2 The Ag cathode catalyst layer was fixed on Ziglarset 39BC carbon paper by spray coating. For the anode, 1 mg cm -2 The Ir black was fixed onto a porous titanium frit. The measurements were performed at T = 50 °C by continuously supplying 1 M KOH anolyte to the anode compartment (approximately 9 cm 3 cm -2 min -1 ) while the cathode compartment was filled with humidified (room temperature deionized water) CO at u = 12.5 cm 3 cm -2 min -1 The mixture was purged at a flow rate of 1000 rpm.

[0093] Figure 24 suggests that the selectivity for CO production increases significantly with increasing CO2 pressure, thus allowing further control of the syngas product composition (H2 / CO ratio).

[0094] [overview] As is apparent from the above, the present invention provides / presents: Electrochemistry for efficient electrochemical conversion of carbon dioxide stack structure. Pressure handling up to 30 bar (preferably 20 bar) through cathode and anode side pressure chambers. Pressure resistance, i.e. electrolytic cell stack The pressure applied to the stack Improves the coordination of components, sealing elements and electrical contacts by compensating for the negative effects of imperfect matching of component dimensions due to fabrication, thus stack Increased performance is obtained. High mechanical strength components (e.g. stainless steel, titanium, metal alloys or composite frameworks). · A specific sealing system including O-rings and pressure chambers (both on the anode and cathode side) placed in recesses / grooves. Highly scalable stack Structure, both in terms of size or physical dimensions due to modular construction; cell in terms of number of and product yield. Multi-in-series and parallel gas supply cell Structure (important for scale-up): the initial CO2 gas stream is: (i) stack All are divided within cell (Parallel conversion is done in various ways.) cell (ii) the entire CO2 feed is cell one after the other (serial design). The above two scenarios (i.e., series or parallel gas management on the cathode side) have the same stack This is achieved by simply assembling the structural elements differently. stack This is ensured by the modular structure and the multifunctionality of the elements, in particular the anode side spacer element, which, due to its very specific design, stack This allows for series or parallel gas management. · stack Due to the modularity of the stack Inside, electrolytic cell cell It is possible to connect some of them in parallel while connecting others in series. Modularity also ensures the use of different ion exchange membranes, gas diffusion layers and catalysts without changing the overall structure (but still maintaining pressure resistance). High conversion rates as a result of: Direct gas supply, High pressure capability, Controlled residence time ( stack along with the geometry), · Specific flow pattern (central supply of CO2, radial collection of products). ·Electrolytic cell stack To facilitate gas and liquid transport within cell New design for connecting to each other. A wide variety of catalysts can be used in the electrolytic cell, including but not limited to Sn, Pb, Ag, Cu, Au, C, Fe, Co, Ni, Zn, Ti, Mn, Mo, Cr, Nb, Pt, Ir, Rh, Ru, and different binary compositions and oxides formed therefrom. · A number of different products formed with different compositions, for example but not limited to hydrogen, carbon monoxide, ethylene, methane. ·CO2 electrolyzer stack The ability to produce, for example, synthesis gas and ethylene even on an industrial scale using Ag / C and Cu / C catalysts, respectively. Operating parameters (input flow, humidification, pressure, stack Possibility to optimize the flow (temperature, flow pattern and its thickness, GDL compression). Adjustable syngas composition, simply stack This can be achieved by varying the voltage.

[0095] Moreover, as will also be clear to those skilled in the art, the solution of the present invention, whether considered alone or in any combination, is also applicable to the exemplified embodiment, i.e. an electrolytic cell for converting gaseous carbon dioxide. stack The present invention is not limited to this but can also be applied in other electrochemical setups (e.g., N2-reduction to ammonia, etc.).

[0096] Considering the above, from a technical point of view, Cell Stack Instead of a multi-layered structure, similar to that shown in Fig. 1, cell Assembling an electrolytic cell reduces capital investment costs because: stack The frame and anolyte circulation loop need only be constructed once, and further cell only requires an additional bipolar plate assembly, some sealing elements and an additional membrane / electrode assembly.

Claims

1. Gaseous carbon dioxide (gaseous CO ２ Electrolyser stack (100', 100") for converting 1,2-dichloroethane (CO2) into at least one gas phase product exiting the electrolyser stack (100', 100"), a cathode end unit (26) having a gas inlet (21), a fluid inlet (23), a fluid outlet (24) and electrical terminals; an anode end unit (27) having a gas outlet (22) and an electrical terminal; At least two electrolyzer cells (40) sandwiched between the cathode end unit (26) and the anode end unit (27); Each electrolyzer cell (40) comprises: A cathode current collector (5: 5a, 5b, 5c, 5d); an anode current collector (10); A membrane / electrode assembly, an ion exchange membrane (7) having a first side and a second side; a cathode catalyst layer (6b) arranged on said first side and in contact with said membrane (7); a cathode-side gas diffusion layer (6a) arranged on and in contact with the cathode catalyst layer (6b); an anode catalyst layer (8b) arranged on said second side and in contact with said membrane (7); an anode-side gas diffusion layer (8a) arranged on the anode catalyst layer (8b) in contact with the anode catalyst (8b); A membrane / electrode assembly comprising: a spacer element (9) arranged between the cathode current collector (5: 5a, 5b, 5c, 5d) and the anode current collector (10), the spacer element (9) is configured to sandwich and fix the membrane / electrode assembly between the cathode current collector (5:5a, 5b, 5c, 5d) and the anode current collector (10), and between the cathode current collector (5:5a, 5b, 5c, 5d) and the anode current collector (10); Where: the cathode side gas diffusion layer (6a) is in partial contact with the cathode current collector (5:5a, 5b, 5c, 5d) so as to form a cathode side internal flow structure (5″) therebetween; and the anode-side gas diffusion layer (8a) is in partial contact with the anode current collector (10) thereby forming an anode-side internal flow structure (5') therebetween; a spacer element (9) configured to separate the cathode current collectors (5:5a, 5b, 5c, 5d) and the anode current collectors (10) from each other; a closed continuous cell gas flow path extending through said cathode lateral inflow structure (5'') within said cell (40) between a cell gas inlet (46) and a cell gas outlet (47); a closed continuous cell fluid flow path extending through said anode side internal flow structure (5') within said cell (40) between a cell fluid inlet (48) and a cell fluid outlet (49); Including, Where: the electrical terminal of the cathode end unit (26), the at least two electrolyzer cells (40) and the electrical terminal of the anode end unit (27) are electrically connected in series; and a cell gas flow path in the electrolyzer cell (40) having gas transport channels (34, 35) extending through the cathode current collectors (5:5a, 5b, 5c, 5d), the spacer elements (9) and the anode current collectors (10) between adjacent cells (40) forms a continuous gas flow path extending from the gas inlet (21) to the gas outlet (22); ２ is supplied to each cathode side gas diffusion layer (6a), and the CO ２ is converted to said gas phase products via at least one cathodic electrolysis reaction occurring in said cathode lateral in-flow configuration (5'') of each electrolyzer cell (40), said products being discharged through said gas outlet (22); and an electrolyzer stack (100', 100"), wherein cell fluid flow paths in the electrolyzer cells (40) having fluid transport channels (38, 39) extending through the cathode current collectors (5:5a, 5b, 5c, 5d), the spacer elements (9) and the anode current collectors (10) between adjacent cells (40) form a continuous fluid flow path extending from the fluid inlet (23) to the fluid outlet (24), wherein liquid anolyte is supplied to each anode lateral flow structure (5') and the cathode electrolysis reaction is completed along with at least one anodic electrolysis reaction occurring in the anode lateral flow structure (5') of each electrolyzer cell (40), and the liquid anolyte and reaction product(s) forming in the anodic electrolysis reaction are discharged through the fluid outlet (24).

2. At least some of the cell gas flow paths of the electrolyzer cells (40) are connected in series with each other; or The electrolyzer stack (100', 100") of claim 1, wherein at least a portion of the cell gas flow paths of the electrolyzer cells (40) are connected in parallel with each other.

3. 3. The electrolytic cell stack (100', 100") of claim 2, wherein the spacer element (9) comprises internal gas transport channels (36) passing therethrough in a first peripheral region of the spacer element (9), the spacer element (9) further comprising a second peripheral region diametrically opposite the first peripheral region, the second peripheral region configured to function as a means for selectively choosing the manner in which two adjacent cell flow paths connect with each other in the gas flow paths of the electrolytic cell stack (100', 100"), the means being provided as a further internal gas transport means (36) in the second peripheral region.

4. 4. The electrolyzer stack (100', 100") according to any one of claims 1 to 3, wherein assembly aid recesses (52) are formed in peripheral edges of the cathode end unit (26), the anode end unit (27), and each of the cathode current collectors (5: 5a, 5b, 5c, 5d), the spacer elements (9) and the anode current collectors (10) of each electrolyzer cell (40) of the electrolyzer stack (100', 100") to aid in rapid and proper assembly and / or reassembly of the stack (100', 100").

5. A cathode pressure chamber (31) is formed in said cathode end unit (26); and An anode pressure chamber (32) is formed in the anode end unit (27); 5. The electrolyzer stack (100', 100") of any one of claims 1 to 4, wherein the gas flow paths are passed through the cathode side pressure chamber (31) and the anode side pressure chamber (32) to provide adaptive pressure control over the electrolyzer cells (40), thereby providing uniform pressure distribution throughout the electrolyzer cells (40).

6. said cathode current collector (5:5a, 5b, 5c, 5d) of each electrolyzer cell (40) is formed as the second component (40b) of a two-component bipolar plate assembly (40'); and 6. The electrolyzer stack (100', 100") of any one of claims 1 to 5, wherein the anode current collector (10) of each electrolyzer cell (40) is formed as a first component (40a) of the two-component bipolar plate assembly (40').

7. 7. The electrolyzer stack (100', 100") according to claim 6, wherein the second component (40b) of the two-component bipolar plate assembly (40') comprises a system of flow channels (5") in its surface facing the membrane (7) arranged to provide a uniform gas distribution over the cathode side gas diffusion layer (6a).

8. 8. The electrolyzer stack (100', 100") according to any one of claims 6 to 7, wherein the first component (40a) of the two-component bipolar plate assembly (40') comprises a system of flow channels (5') in its surface facing the membrane (7) arranged so as to provide a uniform fluid distribution over the anode side gas diffusion layer (8a) such that the anode current collector (10) of each electrolyzer cell (40)

9. 9. The electrolyzer stack (100', 100") according to any one of claims 6 to 8, wherein the first and second components (40a, 40b) of the two-component bipolar plate assembly (40') further comprise ports (41, 42, 43, 44, 46, 47, 48, 49) for fluid / gas communication between opposite surfaces of the first and second components (40a, 40b) and respective cavities (33a, 33b, 33c, 33d) completely surrounding the ports.

10. 10. The electrolytic cell stack (100', 100") of claim 9, wherein the cavities (33a, 33b, 33c, 33d) are sealed separately when the stack (100', 100") is assembled.

11. The electrolyzer stack (100', 100") according to any one of claims 1 to 10, wherein the anode side gas diffusion layer (8a) of each electrolyzer cell (40) is selected from the group consisting of Ti-frit in the form of pressed Ti powders of different particle sizes, Ni-frit in the form of pressed Ni powders of different particle sizes, Ti-mesh and Ni-mesh.

12. Electrolyser stack according to any one of claims 1 to 11, wherein the cathode catalyst (6b) is selected from the group consisting of Ag / C catalysts and Cu / C catalysts.

13. The anode catalyst (8b) is IrO ｘ , RuO ｘ , NiO ｘ and TiO ｘ 13. The electrolyser stack of any one of claims 1 to 12, selected from the group consisting of:

14. The electrolyzer stack (100', 100") according to any one of claims 1 to 13, wherein the number of electrolyzer cells (40) is at most ten.

15. Gaseous carbon dioxide (gaseous CO ２ 1. An electrolytic cell setup (200) for converting 1,2-dichloroethane (COOH) into at least one gas phase product, said setup (200) comprising: An electrolyser stack (100', 100") according to any one of claims 1 to 14, Gaseous CO ２ Source (201), A source of liquid anolyte (213); an external power source (220) having a first pole of a first charge and a second pole of a second charge, the second charge being of opposite sign compared to the first charge, the first pole being electrically coupled to the electrical terminal of the cathode end unit (26) of the electrolytic cell stack (100', 100") and the second pole being electrically coupled to the electrical terminal of the anode end unit (27) of the electrolytic cell stack (100', 100"); The gaseous CO ２ The gaseous CO ２ a cathode flow path assembly for flowing gas from a source (201) through the gas flow paths of the electrolyzer stack (100', 100") to at least one product vessel; an anode side flow path assembly for flowing the liquid anolyte (213) from the liquid anolyte (213) source through the fluid flow paths of the electrolyzer stack (100', 100"); Setup (200).

16. The cathode side flow passage assembly includes: ２ 16. The electrolytic cell setup (200) of claim 15, further comprising a humidifier (203) arranged upstream of the electrolytic cell stack (100′, 100″) for humidifying said electrolytic cell stack (100′, 100″) before feeding said electrolytic cell stack (100′, 100″).

17. 17. The electrolyzer setup (200) according to claim 15 or 16, wherein the cathode side flow path assembly further comprises a back pressure regulating valve (209) arranged downstream of the electrolyzer stack (100', 100") to increase the pressure differential prevailing in the electrolyzer stack (100', 100").

18. 18. The electrolyzer setup (200) of claim 17, wherein the cathode side flow path assembly further comprises a water separator (208) arranged downstream of the electrolyzer stack (100', 100") and upstream of a backpressure regulating valve (209) for removing water from the gas phase product(s).

19. 19. The electrolyzer setup (200) according to any one of claims 15 to 18, wherein the anode side flow path assembly also comprises a liquid anolyte refreshing unit (211) for regenerating the anolyte (213) and / or separating the reaction product(s) forming in the anodic electrolysis reaction(s) from the anolyte (213), if necessary.

20. 20. The electrolyzer setup (200) of claim 19, wherein the liquid anolyte refreshing unit (211) is thermally coupled to a regulating means (212) for regulating the temperature of the anolyte (213).

21. 21. The electrolytic cell setup (200) of any one of claims 15 to 20, wherein the anolyte is an aqueous KOH solution.

22. Gaseous carbon dioxide (gaseous CO ２ 1. A process for converting a benzene ring into at least one vapor phase product, comprising the steps of: Providing an electrolyser stack (100', 100") according to any one of claims 1 to 14, - assembling an electrolytic cell setup (200) according to any one of claims 15 to 21 by using said electrolytic cell stack (100', 100"), Gaseous CO ２ through the electrolytic cell stack (100', 100") of the electrolytic cell setup (200), CO ２ simultaneously flowing liquid anolyte (213) through the electrolytic cell stack (100', 100") of the electrolytic cell setup (200); and The CO ２ and conducting a cathode electrolysis reaction and an anode electrolysis reaction in the electrolyzer stack (100', 100") while flowing the anolyte; and ２ in a continuous flow to said at least one gas phase product; The at least one gas phase product is reacted with the gaseous CO ２ separating said Optionally, if necessary, regenerating the anolyte (213); and Discharging said at least one gas phase product from said electrolyzer setup (200). A method comprising:

23. 23. The method of claim 22, wherein a Ag / C cathode catalyst is used to produce a mixture of hydrogen and carbon monoxide as the gas phase products.

24. 23. The method of claim 22, wherein a Cu / C cathode catalyst is used to produce ethylene as the gas phase product.

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