Method and system for automated optimization of COX electrolysis reactors

Abstract

Methods and systems related to the field of carbon capture and utilization are disclosed. The disclosed method for controlling an electrolysis system using multiple electrolysis cells includes several steps. The electrolysis system is configured to generate CO x The method converts a fluid stream containing at least one chemical into at least one chemical. The method includes monitoring the plurality of electrolytic cells using at least one sensor. The method also includes identifying a depleted cell in the plurality of electrolytic cells by monitoring. The method also includes modifying an operational state of the plurality of electrolytic cells upon identifying the depleted cell while continuing to operate at least one other cell in the plurality of electrolytic cells.

Description

[Background technology]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Patent Application No. 17 / 403,453, filed August 16, 2021.

[0002] background Carbon dioxide (CO2) accumulation in the atmosphere is the main cause of global warming. Capturing it at emission point sources or directly from the air (by direct air capture) and converting it into useful chemicals and fuels using a decarbonized electricity source is a promising method to reduce its atmospheric concentration and provide a sustainable alternative to current fossil fuel-derived feedstocks. Among the envisaged conversion technologies, the polymer electrolyte membrane-based electrolytic reduction technology stands out by its versatility (possible use in a wide range of temperatures and pressures, possible intermittent use) and amenability to produce a wide range of products.

[0003] The electrolytic reduction of CO2 has been reported to generate carbon monoxide, CO, formic acid, ethylene, ethanol, ethane, propanol, propylene, and acetaldehyde, among other products. The potential of this technology has been covered by several reviews. The electrolytic reduction of CO2 favorably generates bicarbonate and carbonate ions (HCO3 - and CO3 2- ) is also being investigated. This is of particular interest since the primary CO2 capture technology involves contacting CO2 with aqueous alkaline solutions to form bicarbonate- and carbonate-containing compounds, such that their added value is limited. Finally, increasing attention is being paid to CO electroreduction. In combination with the first step of ensuring the conversion of CO2 to CO (by any means, such as, but not limited to, electroreduction, hydrogenation of CO2, or gasification of carbon-containing feedstocks, such as, but not limited to, waste, biomass, etc.), CO electroreduction has been reported as a potential economically viable means to produce certain commodities, such as ethylene. Other sources of CO2, such as, but not limited to, NH3, NO2, and NO3 -The co-electrolytic reduction of CO and N-containing reactants such as CO, CO(II), and CO(II) is also important for reinventing industrial chemical processes involving the creation of C-N bonds.

[0004] In the following disclosure, CO, CO, and other members of the oxocarbon family are collectively referred to as CO x It is called CO x Electrolysis reactors typically consist of one or more stacks, each containing at least one or more cells stacked on top of one another. In the stack, each individual cell comprises two half-cells, i.e., an anode compartment, where oxidation of water or an alternative reactant occurs, and an ionically conductive medium, such as, but not limited to, a polymer electrolyte membrane, interfaced by an ionically conductive medium. x and a cathode compartment where the reduction of the reactants to the target products takes place. Each half-cell consists of a flow field that ensures both electrical contact and the supply of reactants to a porous and electrically conductive support (such as a gas diffusion layer (GDL) or a porous metal support), the latter being in direct contact with a catalyst on whose surface the reaction takes place. The assembly formed by the two porous supports and the respective catalysts together with the central membrane or membranes is called a membrane electrode assembly (MEA). In the stack, the individual cells are physically supported on both sides by electrically conductive polar plates (either bipolar or monopolar). The bipolar plates support the flow fields of one cell and the next on both sides and ensure the series connection between the two adjacent cells. At each end of the stack, the terminal polar plates are called monopolar because they only support the flow fields and the adjacent cell on one of their sides. For the sake of brevity in the following, a cell refers to both the central catalyst assembly (such as, but not limited to, an MEA when the ionically conductive medium is membrane-based) including the two flow fields and the supporting polar plates.

[0005] Several other electrolysis reactor configurations are possible. Several prior art works report circular modular electrolysers and processes for converting carbon dioxide to gaseous products at high pressures and high conversion rates, or provide examples of rectangular electrolysers for gaseous carbon dioxide conversion. In all cases, the focus is on the architecture of the cell.

[0006] A wide variety of membrane electrode assemblies are also possible. Much effort has been devoted to the search for catalyst candidates that vary both in their chemistry (e.g., metal alloys, single metal site catalysts, molecular species, use of additives) and structure (e.g., nanoparticles, dendrites, films). In all cases, much effort has been devoted to chemically modifying the electrocatalytic systems to enhance their performance and stability.

[0007] CO x Electrolysis reactors are complex and therefore subject to frequent breakdowns and performance degradation. They can be difficult to maintain and are difficult to access for the human operators responsible for maintenance. These reasons above can lead to high operating costs. On the path to industrialization, there is currently a need to maximize reactor performance metrics as well as the capacity factor (i.e. the ratio between the actual speed at which the plant production runs and the maximum production rate). It is also desirable to limit the maintenance costs and reduce the maintenance time of electrolysis reactors with multiple electrolysis cells. The solution could be to find a way to maintain the performance of the stack for as long as possible before shutting down the system for maintenance operations and to minimize the duration of such maintenance operations. Summary of the Invention [Problem to be solved by the invention]

[0008] overview Methods and systems related to the field of carbon capture and utilization are disclosed. The methods and systems described in this disclosure are directed to the electrochemical reduction of CO2 stored in the atmosphere. x to other chemicals, such as beneficial and sustainable chemicals and / or fuels, as well as to automatically control and optimize the efficiency of an electrolysis system or electrolyzer, including an electrolysis stack. [Means for solving the problem]

[0009] Certain embodiments of the present invention relate to methods and systems for increasing the utilization time of an electrolysis system at a given performance level. The performance level of an electrolysis system may be reduced due to the effects of degraded cells and / or degraded stacks. As used herein, the term "degraded cells" includes cells predicted to degrade due to a detected operating condition of the cells, cells whose performance has been measurably degraded, and faulty cells whose performance has been degraded to the point that they are no longer substantially functional. Similarly, the term "degraded stacks" includes stacks predicted to degrade due to a detected operating condition of the stacks, stacks whose performance has been measurably degraded, and faulty stacks whose performance has been degraded to the point that they are no longer substantially functional. A degraded / faulty stack may include a stack that includes more than an acceptable number of degraded / faulty cells. Some of the methods described herein relate to monitoring the performance of an electrolysis system, identifying degraded and / or faulty conditions, and triggering measures to minimize degradation, avoid failure, and / or resolve failure. In this regard, methods are disclosed that include identifying degraded and / or faulty cells and / or stacks, and modifying the operating conditions of such cells and / or stacks to delay further degradation and eventual failure. Such a method may, for example, include modifying operating parameters in the system to extend cell and / or stack operation. The method may further include identifying faulty cells among the degraded cells (e.g., cells whose degradation exceeds a certain limit or cells that are not functioning at all). In these cases, modifying the operating state may include actually disabling the cells and / or stacks in the system. If the number of faulty cells exceeds an acceptable value, resulting in a large amount of converted CO x If the total amount is too low (e.g., because too many cells are disabled), a replacement step can be performed to change the failed cells as quickly and efficiently as possible via mechanical helpers such as, but not limited to, those illustrated in this disclosure.

[0010] In this disclosure, the term degraded cell includes cells whose operational characteristics, such as electrical resistance, differ from a reference value. Although the example of electrical resistance is generally used in this disclosure, those skilled in the art will recognize that other operational characteristics, such as those that depend directly or indirectly from electrical resistance (e.g., voltage and current), can be used to identify degraded or failed cells. The electrical resistance of a cell is defined as the ratio between the cell voltage (the potential difference between the two electrodes of the cell) and the current flowing through the cell. The electrical resistance of a cell can be obtained by different means, such as, but not limited to, using impedance spectroscopy techniques, or can be inferred from measurements of current and cell voltage. Alternatively, the electrical resistance of a cell can be inferred directly from cell voltage measurements and the current of one or more cells connected in series with the first cell.

[0011] The reference value may depend on multiple factors, including, but not limited to, the geometry of the system, the nature of the reaction, the type of target product, and the operating conditions. The reference value of the electrical resistance of a cell can be established based on knowledge of the expected behavior of the system or system components. It can also be defined in relation to the electrical resistance of other cells, for example, by comparing the electrical resistance of the cell to the average electrical resistance of a group of cells in a plurality of cells. The reference value can be a fixed value, or a correction factor can be integrated to account for the operating conditions of the system, such as the temperature difference between the cells. Different reference values ​​can then be used for different cells with different operating conditions. Based on the above definition, a degraded cell can be defined by an electrical resistance that differs relatively from its reference value. In certain embodiments of the present invention, the electrical resistance differs from its reference value by at least 0.1%. In certain embodiments of the present invention, the electrical resistance differs from its reference value by at least 0.5%. In certain embodiments of the present invention, the electrical resistance differs from its reference value by at least 1%. In certain embodiments of the present invention, the electrical resistance differs from its reference value by at least 1.5%. In certain embodiments of the present invention, the electrical resistance differs from its reference value by at least 3%. In certain embodiments of the invention, the electrical resistance differs from its reference value by at least 5%. In certain embodiments of the invention, the electrical resistance differs from its reference value by at least 10%. These differences can be either positive or negative. In certain embodiments of the invention, the thresholds used to define degraded cells can be adjusted by the system operator according to the desired performance level.

[0012] In certain embodiments of the invention, a degraded cell is a failed cell, which is a cell whose difference in a particular operating characteristic (e.g., electrical resistance) relative to a reference value exceeds a certain threshold. Thus, a failed cell can be defined by an electrical resistance that differs relatively from its reference value. In certain embodiments of the invention, the electrical resistance differs from its reference value by at least 3%. In certain embodiments of the invention, the electrical resistance differs from its reference value by at least 5%. In certain embodiments of the invention, the electrical resistance differs from its reference value by at least 10%. In certain embodiments of the invention, the electrical resistance differs from its reference value by at least 20%. In certain embodiments of the invention, the electrical resistance differs from its reference value by at least 30%. In certain embodiments of the invention, the electrical resistance differs from its reference value by at least 50%. These differences can be either positive or negative. In certain embodiments of the invention, the thresholds used to define a failed cell can be adjusted by the system operator according to the desired performance level.

[0013] By identifying degraded cells / stacks and then modifying the system's operating state accordingly (e.g., by changing the operating parameters to avoid further degradation), it may be possible to extend the system's lifespan. By identifying faulty cells / stacks and then modifying the system's operating state accordingly (e.g., by disabling such cells / stacks), it may also be possible to extend the system's lifespan even after failure. Furthermore, in case too many cells / stacks are disabled, the present invention further proposes a system and mechanism that allows for rapid replacement of cells without significant impact on the overall performance of the system.

[0014] Thus, certain embodiments of the present invention provide a means to extend the life of the electrolysis system, as well as a way to rapidly address cell and stack degradation, failure and replacement. This can be of great advantage in the field of the present invention, as the electrodes of the electrolysis system in certain applications disclosed herein may need to be replaced more frequently, as opposed to other applications where the electrodes are more stable. Similarly, bypassing or disabling may not be as important in other systems, for example when one cell is not producing as much power as it could, as it may be less harmful to the power generation system.

[0015] In certain embodiments of the present invention, a method for controlling an electrolysis system having a plurality of electrolysis cells is provided, the method comprising the steps of: x to at least one chemical. The method includes monitoring the plurality of electrolytic cells using at least one sensor. The method also includes identifying a depleted cell in the plurality of electrolytic cells via the monitoring. The method also includes modifying an operational state of the plurality of electrolytic cells upon identifying the depleted cell while continuing to operate at least one other cell in the plurality of electrolytic cells.

[0016] In certain embodiments of the present invention, an electrolysis system is provided. The system comprises: x receiving a fluid stream containing CO x to at least one chemical. The system also includes at least one sensor configured to monitor the plurality of electrolytic cells. The system also includes at least one processor and a non-transitory computer-readable medium accessible to the at least one processor and storing instructions that, when executed by the at least one processor, cause the system to monitor the plurality of electrolytic cells using the at least one sensor, identify a degraded cell in the plurality of electrolytic cells via the monitoring, and upon identifying the degraded cell, modify an operational state of the plurality of electrolytic cells while continuing to operate at least one other cell in the plurality of electrolytic cells.

[0017] In a particular embodiment of the invention, an electrolysis system is provided. The system comprises a stack of electrolysis cells. The cells of the stack of electrolysis cells include plates, such as, but not limited to, polarity plates. The system also comprises a first stack casing located at a first end of the stack of electrolysis cells. The system also comprises at least one locking mechanism for moving the plates and the first stack casing away from a second end of the stack under some compression. A portion of the stack, e.g., a group of cells, is further individually referred to as a "substack." [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a block diagram of an electrolysis system in accordance with certain embodiments of the invention disclosed herein. [Diagram 2] FIG. 1 includes an example of an electrolysis reactor comprising multiple cells arranged in multiple stacks, according to certain embodiments of the invention disclosed herein. [Diagram 3] FIG. 2 includes an illustration of an electrolysis stack and an open view of one cell according to certain embodiments of the invention disclosed herein. [Figure 4] FIG. 1 is a schematic diagram of a method for automating performance optimization of an electrolysis system for converting COx to chemicals, according to certain embodiments of the invention disclosed herein. [Diagram 5] FIG. 1 is a block diagram and flow chart of a method for mitigating the effects of depleted cells on an electrolysis stack in accordance with certain embodiments of the invention disclosed herein. [Figure 6] FIG. 1 is a block diagram and flow chart of a method for mitigating the impact of a degraded stack on an electrolysis reactor, according to certain embodiments of the invention disclosed herein. [Figure 7] FIG. 2 includes an example of a helper system according to certain embodiments of the invention disclosed herein. [Figure 8]8 includes an example of a perimeter sliding lock system for the helper system of FIG. 7, according to certain embodiments of the inventions disclosed herein. [Figure 9] FIG. 13 includes a helper system for maintaining compression of the two sub-stacks surrounding a central MEA that is replaced during depressurization of the entire stack and another example of its integration within the stack. [Figure 10] FIG. 1 includes a flowchart summarizing some of the methods described herein and the relationships between them, in accordance with certain embodiments of the inventions disclosed herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Detailed Description Certain embodiments of the present invention relate to an electrolysis system. x , or CO x The electrolysis system 100 may be for converting a fluid stream containing carbon dioxide (CO) or carbon monoxide (CO) into at least one chemical, for example, for converting carbon dioxide (CO) or carbon monoxide (CO) into a desired product, such as a carbon-based commodity. FIG. 1 includes a block diagram of an electrolysis system 100 according to certain embodiments of the invention. The electrolysis system 100 includes a CO electrolysis reactor, such as a CO or CO electrolysis reactor. x It comprises an electrolytic reactor 110 , one or more sensors 120 , one or more actuators 130 , a power source 140 , and a control system 150 .

[0020] In a particular embodiment of the present invention, the CO x CO of an electrolysis system such as the electrolysis reactor 110 x The electrolysis reactor receives a fluid stream (e.g., liquid and / or gas) and, upon application of electrical power, converts CO from the fluid stream into CO x The system may be comprised of a plurality of electrolysis cells configured to convert a chemical (such as CO or CO) into at least one chemical, such as an alternative product, which may be a desired and / or useful product (e.g., but not limited to, CO, an alkane, an alcohol, a carboxylic acid).

[0021] 2 includes an example of an electrolysis reactor comprising multiple cells arranged in multiple stacks. In this example, the electrolysis reactor includes a first electrolysis stack 202 comprising M1 electrolysis cells including cell 1, cell n, and cell M1 as shown. The electrolysis reactor represents electrolysis stacks j and N within the reactor, with M1 and M2 being the electrolysis stacks j and N, respectively. j Pieces and M N The reactor includes additional electrolysis stacks, such as electrolysis stacks 204 and 206, which include electrolysis cells. The reactor can include any number of stacks and / or cells, as represented by placeholders 203 and 205, which represent the fact that any other number of stacks can be provided in the reactor.

[0022] The electrolytic cells in the electrolytic reactor can be arranged in different configurations, as shown in FIG. 2. For example, one or several electrolytic cells can be arranged in series. In that case, the anode of a cell can be electrically connected to the cathode of the subsequent cell, and so on. Such an arrangement is called an electrolytic stack. One or several stacks can then be arranged in parallel. In that case, a voltage difference can be applied to the terminal electrodes of each electrolytic stack.

[0023] The cells may have a variety of shapes, including but not limited to circular, or polygonal, such as but not limited to rectangular, square, pentagonal, hexagonal, octagonal, etc. When the cells are arranged in an electrolytic stack, they may adopt similar or different shapes to the other elements of the stack.

[0024] 3 includes an illustration of an electrolysis stack 300 according to certain embodiments of the invention disclosed herein. The stack 300 includes end plates such as 302, monopolar plates such as 304, rigid bars such as 306, membrane electrode assemblies (MEAs) such as 308, flow fields such as 310, and bipolar plates such as 312. Additionally, the stack 300 includes an inlet 314 and outlet 316 for the anode stream, and a CO xIt includes an inlet 318 for the containing cathode stream and an outlet 320 for the cathode stream. Polar plates, such as monopolar plate 304 and bipolar plate 312, can be part of the cells in the stack.

[0025] In the electrolysis stack, the subsequent cells can be physically separated by a bipolar plate (BPP), such as the bipolar plate 312 in FIG. 3, which can ensure mechanical support for each of the electrolysis cells on both sides of the BPP. The BPP also ensures an electrical series connection between the subsequent electrolysis cells, allowing the introduction / removal of reactants / products, respectively. At the end of the stack, only one side of the plate can be in contact with the end cell. This is called a monopolar plate, such as the monopolar plate 304 in FIG. 3. At the end of the stack, a current collector can allow connection to an external power source that can be used for electrical monitoring of the stack, among other elements. The stack can be assembled in a stack casing, allowing its mechanical support and compression, as well as the supply and transport of reactant and product flows to and from the stack. The stack casing can be equipped with end plates that ensure electrical insulation of the stack and provide inlets and outlets for the reactant and product flows.

[0026] In certain embodiments of the invention, the plates (bipolar or monopolar) can include various materials and / or surface coatings. For example, the plates can include stainless steel (such as, but not limited to, 316L), titanium, graphite, or mixtures thereof. The plates can include one or more surface coatings (including, for example, Ti, Cr, Nb, Ni, Fe) on one or more faces of the polar plates that contact the one or more electrochemical cells to minimize contact resistance and improve chemical resistance (especially against corrosion).

[0027] In a particular embodiment of the present invention, the input fluid stream is - , CO3 2-, HO, N, Ar, and / or ion-containing aqueous solutions, such as electrolyte water in the presence of dissolved salts (or mixtures thereof). The input fluid stream may also include SO x OR NO x In certain embodiments of the invention, the anode stream, also referred to as anolyte, may include water in liquid form in the presence of dissolved salts (e.g., CsOH, KOH, CsHCO3, Cs2CO3, KHCO3, K2CO3, NaHCO3, Na2CO3). In certain embodiments of the invention, the cathode stream may include, among others, humidified CO2 and / or CO. For example, humidified CO2 or humidified CO may be used at the cathode, and an ion-containing aqueous solution may be used at the anode. As another example, the cathode stream may be diluted with an inert gas, such as N2 and Ar. HCO3 - and CO3 2- is the solubilized form of CO2 in alkaline media, so HCO3 - or CO3 2- In certain embodiments of the invention, the cathode stream may be composed of CO, CO, HCO3, - , CO3 2- , H2O, N2, Ar. The anode stream may comprise water, H2, an ion-containing aqueous solution. In certain embodiments of the invention, the input cathode fluid stream may also consist of flue gas, for example to value industrial CO2 (from industrial flue gas). In this case, the cathode fluid may contain, in addition to CO2 and / or CO, SO x and NO x In certain embodiments of the present invention, the input anode fluid stream may include wastewater.

[0028] An electrolytic cell is an electrochemical cell that allows for non-spontaneous reactions by using a power source. An electrolytic cell can include at least one of a flow field (e.g., to ensure electrical contact and transport of reactants and / or products), a porous electrode support, an electrode (cathode, anode, etc.), a catalyst (e.g., integral with and / or in contact with the electrode), an ion-conducting medium (e.g., but not limited to, one or more membranes, ion-conducting electrolytes, diaphragms, or oxide-conducting materials, e.g., ceramics). In certain embodiments of the present invention, the flow field can include a ladder, a single or multiple serpentines, an interdigitated pattern, a pillar, a bio-inspired leaf shape, or a mixture thereof. An electrolytic cell can also include polar plates as further discussed in this disclosure.

[0029] In a particular embodiment of the present invention, the porous electrode can be selected from a carbon-based porous support or a metal-based porous material. The carbon-based porous support can be based on carbon fiber, carbon cloth, carbon felt, etc., or a mixture thereof. The carbon-based porous support can be a gas diffusion layer with or without a microporous layer (for example, but not limited to, Sigracet 39BC, Sigracet 35BC, Sigracet 28BB, Sigracet 28BC, Toray paper, Freudenberg H23C6). The metal-based porous support can be selected from titanium, stainless steel, Ni, and can be in the form of a mesh, frit, foam or plate.

[0030] In a particular embodiment of the invention, the ionically conductive medium between the two cathodes and anodes, which ensures ion conduction between adjacent cathodes and anodes, can be made of one or more polymer electrolyte membranes pressed between the anodes and cathodes to form a membrane electrode assembly (MEA).

[0031] In certain embodiments of the present invention, the polymer electrolyte membrane may include, but is not limited to, anion exchange membrane, cation exchange membrane, and / or bipolar membrane. Anion exchange membrane may contain positively charged organic N-containing species such as pyridinium, imidazolium, piperidinium, and additional functional groups to improve mechanical / electronic stability such as styrene or other aromatic or crosslinked polymers. This may include structures that may be commercially available Sustainion, Piperion, Fumasep, or similar structures. Cation exchange membrane may contain anion functional groups such as sulfonic acid groups, phosphonic acid groups, or carboxylate groups. This may be supported on polymer containing aromatic, aliphatic, or fluorinated carbon chains. This may include structures that may be present in commercially available Aquivion, Nafion, or similar structures. Bipolar exchange membrane may include cation exchange membrane in addition to anion exchange membrane, and may be selected from Fumasep FBM, Xion, or may include combinations of structures described in the cation exchange membrane and anion exchange membrane mentioned above. These membranes may also include TiO2, IrO x or NiO x The present invention may include a central water dissociation layer having metal oxide particles such as

[0032] In certain embodiments of the present invention, the catalyst may comprise one or more molecular species, single metal site heterogeneous compounds, metal compounds, carbon-based compounds, polymer electrolytes (also called ionomers), metal organic frameworks, or any other additives. The molecular species may be selected from metal porphyrins, metal phthalocyanines, or metal bipyridine complexes. The metal compounds may be in the form of metal nanoparticles, nanowires, nanopowders, nanoarrays, nanoflakes, nanotubes, dendrites, films, layers, or mesoporous structures. The single metal site compounds may comprise metal doped carbon-based materials or metal-NC based compounds. The metal compounds may comprise Ag, Au, Zn, Cu, Ir, Pt, Fe, Ni, Co, Mn, Sn, Bi, Pd, Pb, Cd, Ru, Re, Rh, alloys of such metals, or mixtures thereof. The polymer electrolyte may be selected from the same materials used in the described membranes. The carbon-based compounds can include carbon nanofibers, carbon nanotubes, carbon black, graphite, boron doped diamond powder, diamond nanopowder, boron nitride, or combinations thereof. The additives can be halide-based compounds including F, Br, I, Cl. The additives can be specifically tailored for hydrophobic modification, such as treatment with polytetrafluoroethylene (PTFE) or carbon black.

[0033] In certain embodiments of the invention, a potential difference is applied to the electrodes to generate a current from the anode to the cathode to generate CO at the cathode. x It can facilitate the reduction of reactants (such as CO2 or CO) to chemicals and the oxidation of reactants at the anode (for example, but not limited to, the oxidation of water to oxygen or the partial oxidation of hydrocarbons or alcohols, the oxidation of organic waste, the oxidation of hydrogen, etc.). The anode reaction can include one or more of the following reactions, which can take place in an acidic / neutral environment (left column) or a neutral / alkaline environment (right column):

[0034] [Table 1]

[0035] The cathodic reaction may include one or more of the following reactions, which may take place in an acidic / neutral environment (left column) or a neutral / alkaline environment (right column):

[0036] [Table 2]

[0037] As a result, the anode stream can include O2 and / or CO2 and / or H2O (or mixtures thereof). The cathode stream can include CO and / or CO2 and / or hydrogen (H2) and / or water (H2O) and / or formic acid (HCOOH) and / or ethylene (C2H4) and / or ethane (C2H6) and / or ethanol (CH3CH2OH) and / or methane (CH4) and / or oxalic acid (COOH-COOH) and / or glyoxylic acid (COH-COOH) and / or propane (C3H8) and / or propene (C3H6) and / or propanol (C3H7OH).

[0038] 1, the electrolysis system 100 also includes a power source 140 that can serve to apply a voltage to the terminal electrodes (monopolar plates) of each electrolysis stack. The voltages applied to the different stacks can vary depending on the number of electrolysis cells in the stack and the operating conditions.

[0039] 1 also includes sensors 120 that can be configured to ensure monitoring of certain operating parameters of the electrolysis system. An operating parameter can be defined as a physical parameter of the electrolysis system that can be measured by a sensor, including, but not limited to, at least one potential difference of at least one electrolysis cell that constitutes the electrolysis reactor, at least one current flowing through at least one cell or stack that constitutes the electrolysis reactor, the molecular composition of the output stream of chemicals, including, but not limited to, the concentration or proportion of CO, CO2, H2, C2H4, CH3CH2OH, and other products (e.g., but not limited to, CO and / or CO2 and / or hydrogen (H2) and / or water (H2O) and / or formic acid (HCOOH) and / or can include, but are not limited to, the molecular composition of the cathode output stream of chemicals including the concentration or percentage of ethylene (C2H4) and / or ethane (C2H6) and / or ethanol (CH3CH2OH) and / or methane (CH4) and / or oxalic acid (COOH-COOH) and / or glyoxylic acid (COH-COOH) and / or propane (C3H8) and / or propene (C3H6) and / or propanol (C3H7OH), and / or the molecular composition of the anode output stream of chemicals including, but not limited to, the concentration or percentage of O2 and / or CO2 and / or H2O and / or H2. x Other operating parameters may also be considered, such as the temperature, humidity, pressure and flow rate of the contained stream or fluids such as water supplied at the anode, and the pH of the anolyte.

[0040] The electrolysis system of FIG. 1 also includes actuators 130 that can be configured to modify either the electrolysis system's operating parameters (including but not limited to temperature / pressure / humidity of the input flows at the cathode and / or anode, flow rates at the cathode and / or anode) or the electrolysis system configuration itself. These can be accomplished, for example, according to instructions provided by a control system described below. In this way, the operating state of the electrolysis system can be modified. Non-limiting examples of actuators are pumps, flow regulators, valves such as two-way valves, three-way valves, gas or liquid heating systems, heat exchangers, electrical contactors, etc.

[0041] The electrolysis system of FIG. 1 also includes a control system 150, which may comprise at least one memory and one processor, or multiple memories, processors and microcontrollers. The memory and processor may be distributed locally or may be hosted remotely, such as on a cloud or an external server, with such distribution being determined for optimal adjustment of the electrolysis system or according to the requirements / constraints of a particular system. The control system may be configured to execute one or more programs, for example, by executing instructions stored in the memory, which, when executed, may cause the system to perform a particular action. For example, the system may receive data transmitted by an operational parameter sensor, such as sensor 120. The data may include performance metrics, such as cell resistance. The data may be further used by the system for subsequent actions, for example, the data may be displayed for live monitoring of the electrolysis system configuration and / or may be stored (e.g., in the form of a time series) for further analysis. As another example, the system may control an actuator, such as actuator 130, to perform an adjustment of an operational parameter (such as temperature, flow rate, pressure, etc.). As another example, the system may analyze data transmitted by an operational parameter sensor. The data can be analyzed for various purposes, such as to provide a live estimate of one or several performance metrics of the electrolysis system. Time series or other data stored in the control system memory can also be analyzed locally or in the cloud or an external server, for example, to provide predictive capabilities of one or several operating parameters and / or performance metrics. As another example, the system can trigger actions such as, but not limited to, issuing an alert to inform an operator of the status of the electrolysis system or to plan maintenance, adapting operating parameter set points according to operator instructions or results of the aforementioned data analysis, modifying the electrolysis system configuration, for example by disabling one or several electrolysis cells and / or stacks, etc.

[0042] In this manner, as described in more detail in the examples below, a system such as system 100 of FIG. 1 can be configured to monitor the plurality of electrolytic cells, e.g., using sensor 120, and to identify, e.g., via monitoring, a cell in the plurality of electrolytic cells that has a particular behavior (e.g., a cell that has an unexpected electrical resistance, as in the case of a degraded cell). The control system can then be configured to modify the operating state of the plurality of electrolytic cells (e.g., by modifying the operating state of the degraded cell) by taking any of the actions described above or other actions. In certain embodiments of the invention, the modification of the operating state can be performed while at least one other cell in the plurality of electrolytic cells continues to operate.

[0043] CO x Electrolysis systems for converting CO2 into chemicals can be complex systems subject to frequent breakdowns and performance degradation. Also, maintenance of electrolysis systems can be complex (e.g., due to the large number of mechanical parts, high compression of bipolar / monopolar plates, etc.), time-consuming and therefore expensive. It may therefore be desirable to find ways to maintain the performance of the electrolysis system and maximize its capacity factor (i.e., the ratio between the actual rate at which the factory production is operated and the maximum production rate), for example by minimizing the duration of maintenance operations.

[0044] Certain embodiments of the present invention relate to methods for controlling electrolysis systems, such as the electrolysis system 100 described with reference to Fig. 1, and automating the performance optimization of such electrolysis systems. In certain embodiments, the described methods are, alternatively or in combination, among others, used to optimize the CO2 electrolysis process involving multiple cells over an extended period of time. x It is possible to provide a method for improving the performance of an electrolysis reactor involving the use of a sintered body of electrolysis cells, minimizing possible failures of electrolysis cells, minimizing the impact of failures of individual cells or groups of cells on the performance of the overall system, and minimizing maintenance time for repairing / replacing failed cells or groups of cells.

[0045] As used herein, the degradation of a cell / cell group / stack or electrolytic reactor, including a fault, can be understood as the degradation of at least one performance metric, such as its electrical resistance, compared to at least one reference value or threshold value. The reference value can be stored in memory for the control system to access it and use it in analyzing data from the sensor. Performance metrics that can be used include measured or calculated indicators of how the cell / cell group / stack or electrolytic reactor functions. Examples of alternative performance metrics (non-exhaustive list) include, among others, the potential difference (voltage) between the two electrodes of an electrolytic cell, the potential difference applied to the monopolar plate of a stack, the sum of the potential differences of a cell group, different stacks, or electrolytic reactors, the current flowing across electrolytic cells or cell groups assembled in series or stacks, the overpotential of an electrolytic cell for generating at least one useful product, defined as the difference between the measured potential difference across the two electrodes of the cell and the thermodynamic potential of the total reaction occurring in the electrolytic cell (the sum of the anodic and cathodic reactions), the overpotential of a cell group, stack, or electrolytic reactor, ... the electrical resistance of the stack or electrolytic reactor, the selectivity or faradaic efficiency of the production of at least one useful product, defined as the ratio of the measured molar amount of the useful product in the outlet fluid stream to the theoretical molar amount that could be achieved if only this useful product were formed in the electrolytic cell / cell group / stack / reactor, the energy efficiency of the electrolytic cell to produce at least one desired product chemical, defined as the faradaic efficiency multiplied by the ratio of the measured potential difference across the two electrodes of the electrolytic cell to the thermodynamic potential of the entire reaction occurring in the electrolytic cell, the energy efficiency of the cell group, stack or electrolytic reactor, the CO converted to the desired chemical x the amount of desired chemical formed, and the operating costs of the electrolysis reactor.

[0046] Based on the aforementioned list of performance metrics, some non-exhaustive examples of undesirable behavior such as failures can be given. For example, the presence of excess water at the anode or COx Flooding of the cell's cathode due to inadequate humidification of the containing cathode stream can result in the loss of CO to the cell's useful products due to increased water reduction to H2 at the cathode. x This can result in a loss of selectivity for reduction. This situation can reduce the resistance of the cell and cause, for example, degradation modes beyond a defined threshold. At the reactor level, it can reduce the production of the desired product in a flooding situation. As another example, the accumulation of impurities at one or other electrode of an electrolysis cell can result in a reduction in the current flowing across the cell, an increase in the cell's voltage / overvoltage and therefore an increase in the cell's resistance. As another example, excessive cooling of the electrolysis stack can result in a reduction in the current flowing across the stack / an increase in its electrical resistance.

[0047] Figure 4 shows the CO x 1 includes a schematic diagram of a method 400 for automating performance optimization of an electrolysis system, such as the electrolysis system 100 of FIG. 1, for converting carbon dioxide (such as CO2 and CO) into chemicals. As shown, the method 400 can be performed by the control system 150, for example, by one or more processors executing instructions stored in a memory.

[0048] The method 400 includes monitoring 402 at least one performance metric, such as cell resistance, of the different cells, possibly by monitoring cell voltages and currents and / or one or several operating parameters. As explained, an operating parameter can be defined as a physical parameter of the electrolysis system that can be measured by a sensor.

[0049] The method 400 further includes a step of detecting 404 the degradation, which may include, among other things, detecting 406 the failure of an electrolysis cell, cell group or stack. The detection 404 and / or 406 may be performed by comparing at least one performance metric, such as cell resistance, to its reference value. Upon detecting the degradation 404 or failure 406, the method may include a step of triggering 408 one or more actions, such as, but not limited to, initiating a numerical simulation 408a of the future performance of at least one cell, for example, by using a time series of past operating parameters as described below, modifying the operating parameters 408b in response to the degradation identification, issuing an alarm 408c to notify an operator of the electrolysis reactor that a threshold has been exceeded (which may indicate a degradation condition, including a fault condition), or that a threshold has been exceeded for at least one performance metric, such as cell resistance, based on the results of the numerical simulation 408a, electrically bypassing the failed cell / cell group or stack if a failure is identified 408d, and / or using a help mechanism 408e, for example, to facilitate cell maintenance in case of a failure identification. The actions mentioned are non-exhaustive and multiple other actions can be taken as indicated by the placeholder 408f. These actions can be taken to modify the operating condition of the system or a part of the system, such as a cell or a group of cells. The method 400 represents an overview of steps that can be taken depending on the desired outcome. Details and implementations of the method for automating the performance optimization of an electrolysis system outlined in FIG. 5 are provided below.

[0050] In certain embodiments of the invention, a control system, such as the control system 150 of FIG. 1, is configured to mitigate electrolysis failures. In an electrolysis system, it may be desirable to automate the mitigation of the effects of a degraded or failed cell, cell group or stack. This can ensure that the system can operate efficiently for longer periods of time without human intervention or maintenance. In this regard, certain embodiments of the invention relate to methods for mitigating the effects of a degraded cell on an electrolysis stack and methods for mitigating the effects of a degraded stack on an electrolysis reactor.

[0051] FIG. 5 includes a block diagram and a flow chart of a method 500 for mitigating the effect of a degraded (e.g., failed) cell on an electrolytic stack. The method 500 includes a step 502 of monitoring at least one cell voltage and / or stack current to infer the resistance of at least one cell. This step may include measuring at least one potential difference (voltage) between the anode and cathode of the electrolytic cell and / or measuring the current flowing across the stack. Optionally, this step may also include directly measuring the cell resistance using impedance spectroscopy techniques. The method 500 further includes a step 504 of detecting a failure, e.g., detecting a failure mode of at least one cell based on comparing at least one cell resistance to a reference value and, optionally, one or more other thresholds (e.g., to generate an alarm), as described above in this disclosure with reference to FIG. 4. The detection of the failure may include detection of a degraded and / or failed cell. As shown in FIG. 5 and with reference to FIG. 4, this step may be performed by the control system 150.

[0052] Method 500 further includes a step of (e.g., automatically) taking an action upon detection of the failure mode. As described with reference to FIG. 4, various actions can be performed by the system, which can be performed individually or in combination with each other. For example, once a cell is identified as exceeding a failure threshold, the cell can be electrically shorted, as represented by step 506. The electrical shorting of the cell can be performed by operation of a normally open electrical circuit located between two electrodes of the cell, which can be closed upon actuation of an actuator. The actuator can be an electronic device, such as a mechanical or solid-state relay, including, but not limited to, a transistor, a thyristor, an optocoupler, a coil-based electrical contactor, and the like. Optionally, a motor-based mechanical device can be used to close the normally open electrical short circuit.

[0053] As another example of an action that can be taken by the system, the voltage applied to the terminal electrodes of a stack containing a degraded cell can be modified, as represented by step 508. The voltage can be reduced to track the drop in electrical resistance of the stack following a cell short (energy efficiency optimization) or to reduce the voltage to track the drop in electrical resistance of the stack following a constant CO2 injection into the chemicals. x The conversion rate can be increased to ensure that the input CO x The flow rate can be modified accordingly, as represented by step 510. A warning can be generated to an operator, as represented by step 512. As described in more detail in this disclosure, other thresholds can be defined to warn an operator that a cell is degrading, and possibly initiate a simulation or take corrective action to prevent cell failure.

[0054] Methods for mitigating the impact of degraded (e.g., failed) cells on an electrolysis stack, such as the method 500 described with reference to FIG. 5, can ensure that electrolysis systems, such as the electrolysis system 100 of FIG. 1, operate efficiently for longer periods of time without human intervention or maintenance. One example of an advantage that can be achieved by shorting a failed cell is that energy loss in the form of heat due to the Joule effect (current flowing through a resistor dissipates energy in the form of heat, and the amount of energy dissipated is proportional to the resistance of the resistor) in the failed cell can be avoided. This advantage can be significant when the degradation is an increase in the resistance of the cell. Another example of an advantage that can be achieved by shorting a failed cell is that undesirable products can be avoided from being produced in the output stream of useful products when degradation causes a loss of selectivity. These and other scenarios are described in more detail below in this disclosure.

[0055] The method for mitigating the effect of a degraded (eg failed) cell on an electrolytic stack described with reference to FIG. 5 can be sequentially applied in a straightforward manner to mitigate the effect of groups of cells within a stack.

[0056] FIG. 6 includes a block diagram and flow chart of a method 600 for mitigating the impact of a degraded (e.g., faulty) stack on an electrolysis reactor. The method 600 can be applied simultaneously or sequentially to multiple stacks including multiple cells. Although FIG. 6 illustrates an example including stacks 650 and 660 including multiple cells such as cells 650a, 650b, 650c, 660a, 660b, 660c, the invention is not limited to such a configuration. If a significant percentage of cells fail within a stack, the stack itself may be considered a faulty stack. In that case, it may be desirable to minimize the impact of a degraded stack on the electrolysis system. The method 600 for mitigating the impact of a degraded stack on an electrolysis reactor includes a step 602 of applying a method for mitigating the impact of a degraded cell on an electrolysis stack to all stacks that make up the electrolysis reactor. Such a step may include performing the method 500 described with reference to FIG. 5.

[0057] The method 600 may further include a step 604 of detecting failures, e.g., detecting a failure mode of at least one stack based on a comparison of the number of shortened cells in the stack or other performance metric with a threshold (e.g., more than 20% of the cells in the stack are bypassed), or with two or more thresholds. For example, a stack may be considered to be faulty if the percentage of faulty cells in the stack exceeds 5%, 10%, 20%, 30%, 40%, and / or 50%. In embodiments in which degraded cells are not shorted by the method of mitigating the effect of degraded cells on the electrolytic stack, the suboptimal cells may remain electrically connected on the circuit. In that case, other performance metrics, such as the total electrical resistance of the stack, may be used to identify the failure mode of the stack. A faulty stack is then defined by an electrical resistance that differs relatively from its reference value by, for example, more than 3%, 5%, 10%, 20%, and / or 30%. This difference may be either positive or negative. Other performance metrics, such as, but not limited to, the energy efficiency and selectivity of the stack, may be used.

[0058] Method 600 further includes implementing (e.g., automatically implementing) one or more actions upon detection of a fault, such as upon detection of a threshold-dependent failure mode, as previously described in this disclosure. In certain embodiments of the invention, a threshold may be set to electrically bypass the stack, as represented by step 606. The electrical bypass may include applying a voltage at the terminal electrodes (monopolar plates) of the stack and bypassing the input CO x In certain embodiments of the invention, this can be done by stopping both the voltage applied to the terminal electrodes of the other stack as well as the input CO x Automatically increase flow rate to ensure consistent CO delivery to chemicals xAs previously described in this disclosure, other actions are possible upon detection of a failure, and other thresholds may be defined to alert an operator to a failure or potential failure, such as that the stack is gradually deteriorating, as represented by step 608.

[0059] In electrolysis systems that include multiple electrolysis stacks, by implementing methods to mitigate the effect of a degraded stack on the electrolysis reactor, the effect of a faulty stack on the operation of the entire system can be minimized, maximizing the performance of the electrolysis system. It can also minimize the maintenance or modifications of the system required to maintain a performance level, for example in terms of low power consumption or high carbon dioxide conversion rate. The voltage and input CO of a non-faulty stack can be reduced by 100%. x In embodiments that allow for automatic correction of flow rates, constant production of the desired product can be achieved.

[0060] Certain embodiments of the invention relate to predictive models for failure avoidance and / or automatic adjustment of operating parameters of degraded cells or stacks. The models may include artificial intelligence models. In electrolysis systems, it may be desirable to automatically adjust operating parameters to prevent or delay cell or stack failure before an actual failure occurs. This may increase the life and overall efficiency of the electrolysis system. In particular, the predictive function may be used to identify possible cell or stack failures, and the classification function may be used to identify the causes of possible cell or stack failures. Automatic adjustment of the electrolysis system operating parameters conditioned on the identification of possible cell or stack failures may then be used to prevent or delay cell or stack failures, as described above with reference to FIG. 4.

[0061] The method of adjusting the operating parameters of an electrolytic stack to prevent cell or stack failure generally can include various steps, such as measuring at least one potential difference (voltage) between the anode and cathode of the electrolytic cell and / or measuring the current flowing across the stack. The method also includes, but is not limited to, measuring the CO x The method may include measuring at least one operational parameter including the temperature, humidity, pressure and flow rate of the stream, or the temperature, humidity, pressure and flow rate of the fluid supplied at the anode, such as an ion-containing aqueous solution, the pH of the anolyte, the molecular composition of the output stream of chemicals, including, but not limited to, the concentrations or percentages of CO, CO2, H2, CH4, CH2H5OH, CH4, and other products as previously described in this disclosure. The method may also include storing the above-mentioned measurements in a control system memory, for example, in the form of a time series (or other data series) including at least two time steps. The method may also include predicting a future time series of at least one performance metric (e.g., cell resistance, cell voltage, stack current, or any other performance metric disclosed previously) using at least one model, such as, for example, a regression model based on an analysis of the stored measurements (e.g., time series) as described above. The method may also include using at least one classification model to predict possible failure modes of one or more cells in the stack based on the predicted future time series. The method may also include modifying at least one operational parameter associated with the operation of the stack in response to a prediction of a possible failure of one or more cells to mitigate a degraded cell before an actual failure occurs. Various examples of such methods and implementations are provided in this disclosure.

[0062] In a method for adjusting the operating parameters of an electrolytic stack to prevent cell or stack failure, different models (e.g., regression models) can be used, such as, but not limited to, linear regression, polynomial regression, kernel-based regression, neural networks, deep neural networks, decision trees, random forest regression, or any other machine learning inspired regression model, or a combination of these models. These models can take as input either only a measured time series of an output parameter (cell resistance and / or other performance metric), or several measured time series of different operating parameters and / or output parameters. The output of these models can be cell resistance, but also cell voltage, stack current, or any other performance metric. For example, an exponential smoothing model that takes only one cell resistance measured time series can be used to predict cell resistance without explicitly considering the effects of other operating parameters (temperature, pressure, humidity, etc.). Such models can be refined to predict cell resistance as a function of the input CO x The flow rate can be linearly or polynomially correlated with the cell temperature and humidity. In a specific embodiment of the invention, a neural network is used to measure the flow rate of the cell resistance, input CO x The stack current can be output based on the historical time series of flow humidity and pressure, and the average temperature of the stack.

[0063] Various classification models can be used to predict possible failures of one or more cells in the stack based on the predicted future time series, such as, but not limited to, threshold models, decision trees, k-means clustering models, support vector machine models, any machine learning inspired classification models, or combinations thereof. These models can be used to analyze the causes of failure modes and help the control system automatically modify the operating parameters to mitigate the degraded cells before failure occurs, thus extending their lifespan. For example, the failure modes of an electrolysis cell can be classified by a k-means clustering model with the degradation rate of the cell resistance as input. A rapid decrease in the predicted cell resistance can be attributed to possible holes in the formation of the membrane, while a slow increase in the predicted cell resistance can be attributed to CO2 emissions. x This may indicate a build-up of impurities on the electrode that inhibits the catalytic reduction of at least one product to the desired product. By using an additional concentration or percentage measurement of at least one product in the product chemical output stream, a flooding event (i.e., the undesirable presence of a large amount of water at the cathode) may be identified because this may increase the probability that water will be electrochemically reduced at the cathode and converted to a higher percentage of dihydrogen H2 in the product chemical output stream.

[0064] Upon classification of the failure mode, the operating parameters can be modified by the control system based on an intelligent understanding of the cause of the failure. For example, if a possible accumulation of impurities at the cathode catalytic site is predicted by a method to adjust the operating parameters of the electrolysis stack to prevent cell or stack failure, the control system can adjust the input CO xA cathode rinse procedure can be triggered by temporarily diverting the flow and injecting a rinse stream consisting of water. Similarly, if the formation of a membrane hole is predicted, a method for mitigating the impact of degraded cells on the electrolysis stack can be used to temporarily electrically short the cells and inject a membrane repair product into the cathode or anode stream. The voltage applied to the terminal electrodes of the stack can also be reduced to reduce the load on the cells. Other modifications of the operating parameters can include, among others, increasing the flow of the anode stream at the anode to cool the stack, decreasing or increasing the flow of the input gas while increasing or decreasing the pressure. Another example includes the detection of a flooding event, for example by measuring the concentration or percentage of H2 in the output stream of useful products, which can be used to adjust (e.g., automatically) the operating parameters of the electrolysis system, such as the humidity of the input CO2 or CO stream, to reduce the amount of water available at the cathode.

[0065] Certain embodiments of the present invention relate to mechanisms for repairing cells, for example, without complete disassembly. In electrolysis systems, such as the system 100 of FIG. 1, it may be desirable to find ways to maximize the capacity factor (i.e., the ratio between the actual rate at which the factory production is run and the maximum production rate), for example, by minimizing the duration of maintenance operations. Helper mechanisms, whether manually operated or automated, can provide a way to accomplish this task. This section describes two such helper mechanisms.

[0066] The electrolytic stack can be combined with a helper system to facilitate maintenance of the stack. This helper mechanical system, when combined with the stack, can maintain compression of a portion of the stack (e.g., a substack as defined above) around one or more cells while disassembling and replacing / regenerating a faulty cell. In certain embodiments, maintaining compression of well-functioning portions of the stack can be important to allow easy and fast maintenance by targeted localized disassembly while maintaining high performance of unmodified cells after such maintenance operations.

[0067] In certain circumstances, when the electrolysis system is restarted after correction of other stack components, it may be important to maintain the compression and alignment of non-degraded cells in order for the cells to retain their performance (similar to that obtained before the maintenance). In certain embodiments of the invention, the helper system may be automatically controlled by any means including the control system 150, an independent control system, or may be manually controlled by an operator. Various designs for the helper system and its interaction with the electrolysis stack may be envisioned to ensure the described characteristics. Two non-limiting examples are provided below.

[0068] The first example refers to a helper system based on a sliding peripheral sub-stack locking system. Figure 7 includes an example of a helper system 700, and Figure 8 includes an example of a peripheral sliding locking system of the helper system. Figures 7 and 8 show an example of a stack outer casing with end plates (705, 706) and rails (701a, 701b, 701c, 701d) that surround the central electrolytic stack (not shown here for clarity) and ensure its mechanical retention and compression determined by any kind of external fastening system 707. Figure 8 presents a peripheral sliding locking system 808 that surrounds a polar plate 810 (bipolar or monopolar) that mechanically attaches itself through lateral recesses (800a, 800b, 800c, 800d, 800f, 800e) by entering an indent machined in the thickness of the central plate 810. The peripheral sliding lock system 808 fits into a frame formed by rails (701a, 701b, 701c, 701d) located at its four corners and guides its movement along the thickness of the stack. It is attached to one of the end plates via a rigid bar (such as, but not limited to, a threaded rod, a ball screw based system, etc.) to allow applying pressure (through a recess) to the substack located between this end plate and the stack plate to which it is attached. Compression of this substack can be ensured by tightening the rigid bar to a target compression level, as monitored by any type of pressure sensor not shown here. Such tightening can be operated by a system such as a motor located on the end plate as exemplified by, but not limited to, 703a, 703b, 703c. Ports 704a, 704b, 704c, 704d represent manifolds for circulating fluids in the electrolytic stack. They are represented on the same end plate as an example, but can also be located on different end plates and / or in different locations on the plates.

[0069] The holes 811a, 811b, 811c of the represented peripheral sliding locking system can be designed to allow the passage of a rigid bar dedicated to the second peripheral sliding locking system. In this way, it is possible to maintain compression on the sub-stacks on each side of the faulty cell or series of cells by positioning a peripheral sliding locking system on the polarity plate on each side of the faulty cell or series of cells. By releasing the compression of the entire stack acting on 707, it may be possible to access one of the faulty cells or series of cells to realize a maintenance operation while keeping the rest of the stack intact. Once the maintenance operation is performed, the entire stack can be compressed again to a target compression level, which can be monitored by any kind of pressure sensor, and the peripheral sliding locking system can be separated from the plate by pulling the lateral recesses (800a, 800b, 800c, 800d, 800f, 800e) from the plate indentations.

[0070] 9 includes another example of a helper system and its integration within a stack to maintain compression of the two substacks surrounding the central MEA to be replaced during depressurization of the entire stack. For simplicity, only the two bipolar plates 901, 902 directly adjacent to the MEA 903 to be replaced are shown in view 900. Furthermore, the system can be designed to maintain compression of both substacks, including i) all polar plates (bipolar or monopolar) between the bipolar plate 901 and the end plate 904 and ii) all plates (bipolar or monopolar) between the bipolar plate 902 and the end plate 905, respectively.

[0071] An example of such a system includes a stack of electrolytic cells including cells, which may include the above-mentioned plates (monopolar plates that are part of one cell, bipolar plates that are part of two cells on either side). The electrolytic stack may also include a casing and locking mechanism (as described above) for at least a portion of the plates and stack casing to be maintained together under a degree of compression while moving or being moved outward from the remainder of the stack. The stack may include, for example, a guide for the plates and stack casing to move. The guide may be a separate guide or an integral guide. One or more additional locking mechanisms may also be included in the stack. For example, a locking mechanism may be provided for fixing a second plate of a cell (not the plate that is moving) against a portion of the stack under a degree of compression when the first plate is moving or being moved outward from that portion of the stack. The stack casing may include an end plate of the stack of electrolytic cells.

[0072] The plate may include an accessible interface, such as a laterally accessible interface, and a connector, such as a removable connector of a locking mechanism, that may be configured to mate with the laterally accessible interface. An actuator of the locking mechanism may be connected to the connector to impart a degree of compression, as described and illustrated with reference to element 707 of FIG. 7. For example, the laterally accessible interface may be a socket in the plate, while the removable connection may be a paddle. As another example, the removable connector may be configured to insert into one or more press-fits of the stack casing when mated with the laterally accessible interface. The locking mechanism described above may be operated by a control loop that may use data from a pressure sensor, for example, as at least a portion of the feedback signal of the control loop. In a particular embodiment of the invention, the locking mechanism may include an actuator and a threaded post extending through the first stack casing, as described above. The actuator may rotate the threaded post to impart a degree of compression.

[0073] In certain embodiments of the invention, using the helper system described above, the depleted cell can be replaced, for example, by moving the plate of the depleted cell together with the stack casing with the electrolysis cells. The other cells can be located between the plate and the stack casing, and they can continue to function as expected after the replacement has been performed. In certain embodiments, the cells can even be configured to continue to function during the replacement process.

[0074] In the helper system shown in FIG. 9, each bipolar plate includes one or more protrusions, such as, but not limited to, tappets 906, as illustrated herein. These may allow a U-shaped mechanism 907 to be inserted on each side of the substack (901) to maintain their respective compression by joining the end plates (e.g., 904) and the final plate, as shown in more detail in view 910. The compression of the substacks may be adjustable by a locking system 908. Once each substack is compressed, the entire stack may not be compressed, allowing for quick and easy extraction 909 of the MEA.

[0075] FIG. 10 includes a flowchart 1000 summarizing some of the methods described herein and the relationships between them. The flowchart 1000 begins with step 1001 of monitoring the electrolysis system. The monitoring step can be performed as described in any of the methods described above and can include monitoring cells, cell groups, and / or stack groups individually. The monitoring can be performed via at least one sensor. As previously described in this disclosure, operational characteristics can be monitored, including performance metrics and operational parameters.

[0076] Flowchart 1000 continues with step 1002 of identifying an undesirable condition. Identifying may include comparing measurements to reference values ​​or thresholds, as previously described in this disclosure. For example, step 1002 may include identifying degraded cells 1002a (e.g., cells whose performance metrics are approaching a failure threshold or not functioning as expected). Step 1002 may also include identifying faulty cells 1102b (e.g., cells that are not working or whose performance metrics have exceeded a failure threshold). Step 1002 may also include identifying degraded stacks 1002c (e.g., stacks with more than an acceptable number of degraded and / or faulty cells). Step 1002 may also include identifying faulty stacks 1002d (e.g., stacks that are not working or have more than an acceptable number of faulty cells). These are non-exhaustive examples of what step 1002 may entail. The idea is that the system can recognize both potential and actual failures and act accordingly.

[0077] Flowchart 1000 continues with step 1003 of modifying the operational state of the system (e.g., the operational state of a cell, a group of cells, a stack). The modification can be performed following the identification in step 1002 and while continuing to operate at least one other cell in the system. Various non-limiting examples of the modification step 1003 are shown in flow chart 1000 and include actions taken by the system as described for other methods described in this disclosure, such as triggering an alarm 1003c. Since the method is intended to identify both potential and actual failures, the modification step can be divided according to the desired remedy. For example, if the result of step 1002 is that there is a degraded cell or stack in the form of a cell that may fail but has not yet failed, the modification step 1003 can include step 1003a of preventing degradation. In this way, the life of the degraded cell / stack can be extended and actual failure can be avoided or at least delayed. If the outcome of step 1002 is that a degraded cell or stack in the form of a faulty cell or stack has been detected, the corrective step 1003 may include a step 1003b of resolving the fault.

[0078] Various examples for modifying the operating state of the system or parts thereof are given throughout this specification, for example, it may be possible to adjust the operating parameters 1004 of the system to extend the life of a degraded cell / stack. On the other hand, in case of a failure 1005, it may be possible to disable a cell, a group of cells, or a stack. In this way, the system can continue to operate despite the fact that some cells / stacks are faulty. This can be done by bypassing these cells / stacks, for example via an electrical bypass. For example, if a degraded cell is in parallel with another cell in the power circuit of the electrolysis system, disabling the degraded cell may include disconnecting the degraded cell from the power circuit of the electrolysis system. Disabling may be a state of not consuming energy, not producing energy, inactive, CO xThe disabling step may include any number of actions such as configuring the cell / stack to a state where no current is reduced, replacing the flow with a different flow, etc. If the cells are in series, the cells may be bypassed, for example by using a conductor. If the cells are in parallel, the cells may be open and flow will stop. In this way, various actions can be taken as part of the disabling step, such as opening a circuit so that no electricity flows through the stack to disable the stack, shorting the cells (e.g., with a conductive metal piece) to disable the cells, disabling individual cells one after the other to disable a group of cells, etc.

[0079] The next step may include the actual replacement 1006 of the cell / stack. This step may be accomplished if there are too many disabled cells in the system or if desired by the operator. The replacement of the cell may then include the use of a helper mechanism 1007 as described in the present disclosure to reduce maintenance time. In this manner, the combination of methods and systems disclosed herein helps to extend the life of the electrolysis system by providing a means not only for monitoring to identify degradation, but also, for example, for automatically implementing system changes upon detection of such degradation to slow degradation and failure. Additionally, the systems and methods provide a means to keep the system operating even if failures are detected, and a means to quickly and effectively repair those failures.

[0080] Although the present specification has been described in detail with respect to specific embodiments of the present invention, it will be appreciated that those skilled in the art, upon gaining an understanding of the foregoing, can readily conceive of modifications, variations, and equivalents of these embodiments. Any of the method steps described above may be performed by a processor operating with a computer-readable non-transitory medium storing instructions for those method steps. The computer-readable medium may be a memory within a personal user device or a network-accessible memory. These and other modifications and variations to the present invention may be implemented by those skilled in the art without departing from the scope of the present invention, which is more particularly set forth in the appended claims.

Claims

1. 1. A method for controlling an electrolysis system having a plurality of electrolysis cells, the electrolysis system comprising: x converting a fluid stream containing monitoring the plurality of electrolytic cells using at least one sensor; identifying a degraded cell within the plurality of electrolysis cells through said monitoring; and modifying an operational state of the plurality of electrolytic cells in response to the identification of the degraded cell while continuing to operate at least one other cell within the plurality of electrolytic cells.

2. The method of claim 1 , wherein the degraded cell is a cell whose electrical resistance differs from a reference value.

3. 3. The method of claim 2, wherein the reference value of the electrical resistance of the depleted cell is defined as an average electrical resistance of a group of cells within the plurality of electrolytic cells.

4. 2. The method of claim 1, wherein modifying the operating conditions of the plurality of electrolysis cells comprises at least one of: (i) modifying operating parameters of the depleted cells to extend the operation of the depleted cells; (ii) disabling the depleted cells; and (iii) replacing the depleted cells.

5. The method of claim 4 , wherein the disabling of the degraded cells comprises electrically disabling the degraded cells.

6. the depleted cell is in parallel with at least one other cell in the power circuit of the electrolysis system; 5. The method of claim 4, wherein the disabling of the depleted cell comprises disconnecting the depleted cell from the power circuit of the electrolysis system.

7. and further comprising identifying a set of depleted cells within the plurality of electrolytic cells prior to identifying the depleted cells through the monitoring. the depleted cell and the depleted cell set are in a stack of electrolytic cells; The method of claim 4 , wherein the disabling comprises disabling a stack of the electrolytic cells.

8. the depletion cell is in a stack of electrolysis cells; The method of claim 1 , wherein at least one other cell is in the stack of electrolytic cells.

9. said identifying said degraded cells further comprising: comparing the cell resistance of the degraded cell with a reference value; and 2. The method of claim 1, comprising one of: predicting the evolution of cell resistance of the degraded cell based on a plurality of past measurements of the cell resistance and an operating parameter of the plurality of electrolytic cells.

10. The method of claim 9 , wherein the predicting uses an artificial intelligence model.

11. The method of claim 1 further comprising generating a warning signal identifying the degraded cell.

12. The depleted cell, replacing the plate of the depleted cell by moving it together with a first stack casing of the stack of electrolysis cells; the plurality of electrolysis cells are in a stack of electrolysis cells; 2. The method of claim 1, wherein at least one other cell of the plurality of electrolytic cells is in the stack of electrolytic cells between the plate of the depleted cell and the first stack casing.

13. 1. An electrolysis system comprising: CO x receiving a fluid stream containing CO x a plurality of electrolysis cells configured to convert the at least one sensor configured to monitor the plurality of electrolysis cells; at least one processor; accessible to the at least one processor and, when executed by the at least one processor, providing the system with: monitoring the plurality of electrolysis cells using the at least one sensor; identifying a degraded cell within the plurality of electrolysis cells through said monitoring; modifying an operational state of the plurality of electrolytic cells in response to the identification of the degraded cell while continuing to operate at least one other cell within the plurality of electrolytic cells; and a non-transitory computer-readable medium storing instructions to cause the system to:

14. The system of claim 13 , wherein the degraded cell is a cell whose electrical resistance differs from a reference value.

15. 15. The system of claim 14, wherein the reference value of the electrical resistance of the depleted cell is defined as an average electrical resistance of a group of cells within the plurality of electrolytic cells.

16. 14. The system of claim 13, wherein modifying the operational state of the plurality of electrolysis cells includes at least one of (i) modifying operational parameters of the depleted cells to extend their operation, (ii) disabling the depleted cells, and (iii) using a helper mechanism to facilitate replacement of the depleted cells.

17. The system of claim 16 , wherein the disabling of the degraded cells comprises electrically disabling the degraded cells.

18. the depleted cell is in parallel with at least one other cell in the power circuit of the electrolysis system; 17. The system of claim 16, wherein the disabling of the depleted cell comprises disconnecting the depleted cell from the power circuit of the electrolysis system.

19. and further comprising identifying a depleted cell set within the plurality of electrolytic cells before identifying the depleted cell through the monitoring, wherein the depleted cell is not included in the depleted cell set; the depleted cell and the depleted cell set are in a stack of electrolytic cells; The system of claim 16 , wherein the disabling comprises disabling a stack of the electrolytic cells.

20. said identifying said degraded cells further comprising: comparing the cell resistance of the degraded cell with a reference value; and 14. The system of claim 13, further comprising one of: predicting the evolution of cell resistance of the degraded cell based on a plurality of past measurements of the cell resistance and an operating parameter of the plurality of electrolytic cells.

21. 21. The system of claim 20, wherein the predicting uses an artificial intelligence model.

22. A plate of the degradation cell; a stack of electrolysis cells; a first stack casing of the stack of electrolytic cells disposed at a first end of the stack of electrolytic cells; at least one locking mechanism for spacing the plate and the first stack casing from the second end of the stack of electrolysis cells under some compression; further comprising the plurality of electrolysis cells are in a stack of electrolysis cells; 14. The system of claim 13, wherein at least one other cell of the plurality of electrolytic cells is in the stack of electrolytic cells between the plate of the depleted cell and the first stack casing.

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