Balance of plant for electrosynthesis or electroenergy liquid gas cells or cell stacks

Abstract

In one example, a gas equalization system (400-401) and method of operation for an electrosynthetic or electroenergy liquid gas cell or cell stack (210) is disclosed. The gas equalization system (400-401) comprises a first equalization tank (410) for partially containing a first liquid (470) and a first gas. The first gas is positioned above a first liquid level (471). A first gas conduit (430) is provided for transferring the first gas between the cell or cell stack (210) and the first equalization tank (410). In another example, a second equalization tank (420) may be provided for partially containing a second liquid (473) and a second gas positioned above a second liquid level (472). A second gas conduit (440) is then provided for transferring the second gas between the cell or cell stack (210) and the second equalization tank (420).

Description

Technical Field

[0001] The present invention relates generally to an electro-synthesis or electro-energy liquid gas cell, a cell stack, and / or a system or method for use with or operating an electro-synthesis or electro-energy liquid gas cell or cell stack. Exemplary embodiments relate to an engineering system, device, configuration or method, referred to as a "balance of plant", that supports and manages an electro-synthesis or electro-energy liquid gas cell or cell stack.

Background Art

[0002] An electro-energy cell is an electrochemical cell that generates electricity over a period of time for use outside the cell. An electro-energy cell is distinguished from other galvanic cells in that it requires a constant external supply of reactants. The products of the electrochemical reaction must also be continuously removed from such a cell. Unlike a battery, an electro-energy cell does not store chemical energy or electrical energy within the electro-energy cell.

[0003] Examples of electro-energy cells include, but are not limited to, polymer electrolyte membrane (PEM) hydrogen-oxygen fuel cells, hydrogen-oxygen alkaline fuel cells, ammonia fuel cells, and the like.

[0004] An electro-synthesis cell is likewise an electrochemical cell that produces one or more chemical substances over a period of time for use outside the cell. The chemical substances may be in the form of a gas, a liquid, or a solid. Similar to an electro-energy cell, an electro-synthesis cell also requires a constant supply of reactants and a constant removal of products. An electro-synthesis cell may generally further require a constant input of electrical energy.

[0005] Examples of electrosynthesis cells include, but are not limited to, electrochemical cells ("water electrolyzers") for producing hydrogen, chlorine ("chlor-alkali" cells), hydrogen peroxide, formic acid, ammonia, and many other industrial products.

[0006] Many electrosynthesis and electrical energy cells are also “liquid-gas” cells, which are cells in which at least one reactant or product is in the liquid phase and at least one reactant or product is in the gas phase. Examples of electrosynthesis cells that are also liquid-gas cells include, but are not limited to, water electrolytic cells that produce hydrogen and oxygen gases from liquid water when electrical energy is applied to the cell, and chlorine gases from liquid brine. Examples of electrical energy cells that are also liquid-gas cells include, but are not limited to, hydrogen-oxygen fuel cells in which hydrogen and oxygen gases are converted into liquid water as electrical energy is generated.

[0007] Another characteristic of electrosynthesis or electrical energy cells is the large volume of reactants and products typically involved in their operation. Such cells typically require a constant supply of a considerable amount of reactants, while simultaneously requiring the constant removal of a considerable volume of products.

[0008] Since large amounts of electrical energy can also be involved in the operation of electrosynthesis or electrical energy cells, a key challenge in their development is to maximize energy efficiency during operation. This can be achieved in part by minimizing their electrical impedance. Impedance is the resistance that a cell circuit imparts to the current. One well-known method of minimizing impedance is to use a cell architecture in which the anode and cathode electrodes of a cell are positioned as close to each other as possible and facing each other without contact (creating a short circuit). In this case, the gap between the two electrodes should also ideally be occupied by an electrolyte having the highest possible conductivity. Generally, liquid electrolytes have the highest conductivity of any electrolyte as a class. Interelectrode membranes / ionomers / diaphragms (also called "separators") may also be placed between the electrodes, typically to prevent contact and to keep the reactants consumed by each electrode and / or the products generated separate from each other. A separator can also prevent a gas generated or consumed on one side of the separator from moving through the separator to the other side, and the gas can mix with another gas generated or consumed by the other electrode. Such movement is called "gas crossover" and can constitute a safety hazard, for example, if one gas is hydrogen and the other gas is oxygen. A mixture of more than about 4% oxygen in a hydrogen body, or more than about 4% hydrogen in an oxygen body, can constitute an explosive mixture that poses a safety hazard at 80°C.

[0009] Another characteristic of industrial electrosynthesis and electroenergy liquid gas cells may be that they are often “stacked” electrically in series with other cells, thereby forming a “cell stack.” This is generally achieved within a so-called “filter press” configuration (also known as a “plate and frame” “filter press” configuration). In such a configuration, individual cells having substantially flat profiles may be stacked between two end plates compressed toward each other. This causes the intervening stacked cells to (i) maintain electrical contact with each other (electrically in series), (ii) be held firmly within the stack, thereby (iii) forming a single electrosynthesis or electroenergy device, i.e., a filter press type cell stack. The resulting cell stack is then effectively a single device having the product outputs from all the incorporated cells, as well as their combined reactant consumption. In this way, large quantities of reactants and products can be accumulated in a single external product and / or reactant flow that is easier to manage than multiple smaller flows.

[0010] Such an engineering system, apparatus, or configuration that supports, manages, and / or controls a single, external, reactant and product flow, as well as an electric current through a cell or cell stack, is known or may be called a “balance of plant” or “balance of system.”

[0011] The balance of plant for electrosynthesis or electroenergy liquid gas cells or cell stacks can consume considerable energy and thus include critical process engineering equipment that impacts the overall energy efficiency of the entire system. Furthermore, the balance of plant can be more expensive than the cells and cell stacks themselves and is an economically important component of the entire electrosynthesis or electroenergy system. The balance of plant can also be critical to ensuring that the cells / cell stacks operate reliably and safely and achieve their specified outputs.

[0012] Therefore, it is necessary to optimize or improve the balance of such plants, and / or the operation of electrosynthesis or electroenergy liquid gas cells or cell stacks, for example, with respect to the components used and their engineering architecture, and in particular their simplicity, efficiency, cost, reliability, and / or safety.

[0013] In many electroenergy liquid-gas cells, the liquid-gas-solid state boundary can exist within or on the electrodes during operation. This allows gaseous reactants to be directly supplied to the cell, where they are converted into liquid products at the liquid-gas-solid interface, for example, by crossing the boundary into the liquid phase. In other words, in many electroenergy liquid-gas cells, the liquid and gas phases of the material present within the cell can be separated relatively well and clearly.

[0014] In contrast, in many electrosynthetic liquid-gas cells, the gas exists in a form mixed with the liquid reactants. For example, the gas may be produced as bubbles of gas within the liquid-phase reactants, for instance, in the form of a “foam” or “bubble” mixture of the mixed gas-phase and liquid-phase substances. This requires removing the mixed two-phase mixture from the cell and separating the two phases elsewhere (i.e., liquid and gas). Such separation is typically carried out in a separation tank or engineering structure specifically designed to allow such a two-phase liquid-gas mixture to be fractionated into separate gas and liquid phases. These separate gas or liquid phases are also called “bulk” gas or liquid phases, and the term “bulk” indicates that the substance in question is substantially single-phase, e.g., gas phase (”bulk gas”) or liquid phase (“bulk liquid”). The balance of the plant usually plays a crucial role in such separation processes.

[0015] However, in recent years, electrosynthetic liquid-gas cells have been developed that maintain a clear separation of the liquid and gas phases. For example, electrosynthetic gas-liquid systems have been developed that directly convert liquid-phase reactants into gas-phase products within the cell. That is, the products are produced in the form of "bulk gas" substantially separated from the liquid-phase substances within the cell, without the need for separation tanks or the like. The liquid-gas-solid state boundary can exist at the electrodes of such a cell in the same way that such boundaries can exist in many electroenergy liquid-gas cells. An example of such a system is described in the scientific publication "The prospects of developing a highly energy-efficient water electrolyser by eliminating or mitigating bubble effects," Swiegers et al., published February 10, 2021, Sustainable Energy and Fuels, 2021, Vol. 5, pp. 1280-1310 (DOI: 10.1039 / d0se01886d). Another example is described in the later scientific publication "A high-performance capillary-fed electrolysis cell promises more cost-competitive renewable hydrogen," Hodges et al., published March 15, 2022, Nature Communications, 2022, Vol. 13, page 1304 (DOI: 10.1038 / s41467-022-28953-x).

[0016] Such electro-synthetic liquid gas systems may require a different balance of plant than conventional systems, and may be relevant for higher energy efficiency, lower costs, and / or improved reliability and safety. In such cases, a new and / or improved balance of plant is needed if the engineering configuration of the balance of plant is not yet established or is immature.

[0017] Another recent development involves detachably combining individual electrosynthesis liquid gas cell stacks into a modular “array” that helps provide reactants, remove products, and / or form the electrical connections of each cell stack. International Publication No. 2022195021 of “Modular Electrochemical Systems,” published on September 22, 2022, describes such an array of water electrolysis cell stacks. In such cases, too, a new and / or improved balance of plant is needed if the overall process engineering configuration of the balance of plant is not yet established or is still immature.

[0018] Any reference in this Specified Publication to any prior publication (or information derived therefrom) or any known matter shall not be construed, nor should be construed, as an acknowledgment, authorization, or any form of suggestion that the prior publication (or information derived therefrom) or known matter constitutes part of the common general knowledge in the field of effort to which this Specified Publication relates. [Overview of the Initiative] [Problems that the invention aims to solve]

[0019] This summary is provided to introduce, in a simplified form, a selection of concepts that will be further explained in the detailed description below. This summary is not intended to identify all of the important or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

[0020] In various exemplary embodiments, the embodiments are as follows: (1) Gas management, for example i. Gas pressure management; ii. Gas pressure equalization; iii. Gas pressure control; and / or iv. Gas circulation or recirculation, including during "standby" periods; (2) Management of liquids; (3) Stack cooling management; (4) Monitoring and managing the status of cells; (5) Configuration and management of cell stacks; and / or (6) Load following and / or grid balancing This relates to a balance of plant and operating method for electrosynthesis or electroenergy liquid gas cells or cell stacks that provides new and / or improved operation in relation to the present.

[0021] Preferably, but not exclusively, all of the following embodiments relate to a balance of plant or operating method in which the operation of sensors, valves, pumps, and other process engineering components is automated by computer control via one or more programmable logic controllers (PLCs) that can be used to operate the balance of plant without requiring human intervention. [Means for solving the problem]

[0022] In one exemplary embodiment, a gas pressure equalization system or method for an electrosynthesis or electroenergy liquid gas cell or cell stack is provided, wherein the cell or cell stack is configured to separate and retain a first gas in bulk form within the cell or cell stack. In a further exemplary embodiment, a gas pressure equalization system or method for an electrosynthesis or electroenergy liquid gas cell or cell stack is provided, wherein the cell or cell stack is configured to separate and retain a first gas in bulk form from a second gas in bulk form within the cell or cell stack.

[0023] In another exemplary embodiment, a gas pressure control system or method is provided for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a first gas in bulk form within the cell or cell stack. In yet another exemplary embodiment, a gas pressure control system or method is provided for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a first gas in bulk form from a second gas in bulk form within the cell or cell stack.

[0024] In another exemplary embodiment, a gas circulation or recirculation system or method is provided for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a first gas in bulk form within the cell or cell stack. In yet another exemplary embodiment, a gas circulation or recirculation system or method is provided for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a first gas in bulk form from a second gas in bulk form within the cell or cell stack.

[0025] In another exemplary embodiment, a liquid management system or method is provided for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a first gas in bulk form within the cell or cell stack. In yet another exemplary embodiment, a liquid management system or method is provided for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a first gas in bulk form from a second gas in bulk form within the cell or cell stack.

[0026] In another exemplary embodiment, a cooling management system or method is provided for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a first gas in bulk form within the cell or cell stack. In yet another exemplary embodiment, a cooling management system or method is provided for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a first gas in bulk form from a second gas in bulk form within the cell or cell stack.

[0027] In another exemplary embodiment, a monitoring or control system or method for an electrosynthesis or electroenergy liquid gas cell or cell stack is provided, which uses a computer chip or one or more computer chips within one or more individual cells in the cell or cell stack.

[0028] In another exemplary embodiment, an electrosynthesis or electroenergy liquid gas cell or cell stack configuration is provided, wherein the cell stack is configured to separate and retain a first gas in bulk form within the cell stack. In yet another exemplary embodiment, an electrosynthesis or electroenergy liquid gas cell or cell stack configuration is provided, wherein the cell stack is configured to separate and retain a first gas in bulk form from a second gas in bulk form within the cell stack.

[0029] In another exemplary embodiment, a load-following or grid-balancing system or method is provided for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a first gas in bulk form within the cell or cell stack. In yet another exemplary embodiment, a load-following or grid-balancing system and method are provided for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a first gas in bulk form from a second gas in bulk form within the cell or cell stack.

[0030] In various exemplary embodiments, the embodiments relate to a balance of plant or operating method for electrosynthesis or electroenergy liquid gas cells, cell stacks, and / or systems, with novel and / or improved gas pressure control.

[0031] In one exemplary embodiment, a balance of plant is provided for an electrosynthesis or electroenergy liquid gas cell or cell stack that can generate or consume a gas with a high absolute pressure, even though the outer wall of the cell or cell stack can only withstand a small internal-external pressure difference.

[0032] In exemplary embodiments, an electrosynthetic or electroenergy liquid gas cell or cell stack is provided, which is incorporated within a pressure vessel, and the cell or cell stack is surrounded by a liquid-phase or gaseous fluid that pressurizes the outer wall of the cell or cell stack. Preferably, the liquid-phase or gaseous fluid is pressurized to and / or has a pressure comparable to the pressure of the gas and / or liquid in the cell or cell stack. Preferably, during operation, the liquid-phase or gaseous fluid is always maintained at a pressure comparable to, close to, or slightly higher than, the pressure of the gas and / or liquid in the cell or cell stack. Preferably, but not exclusively, the pressure difference between the inside of the cell or cell stack and the surrounding liquid-phase or gaseous fluid outside the cell or cell stack is absolutely low, and / or lower than the absolute pressure of the gas and / or liquid in the cell or cell stack. The pressure vessel may surround the cell or cell stack.

[0033] Preferably, the cell or cell stack is sealed to exclude the liquid or gaseous fluid so that it does not penetrate the cell or cell stack and does not come into direct contact with the electrodes within the cell or cell stack. Preferably, but not exclusively, the liquid or gaseous fluid passes continuously through the space between the cell or cell stack and the pressure vessel wall. Optionally, the liquid or gaseous fluid is cooled or heated before passing through the space between the cell or cell stack and the pressure vessel wall, thereby controlling the temperature of the cell or cell stack. Preferably, but not exclusively, the liquid or gaseous fluid is not significantly conductive. Preferably, but not exclusively, the liquid or gaseous fluid is not significantly chemically corrosive.

[0034] In another exemplary embodiment, where the fluid surrounding the cell stack is a liquid-phase fluid ("annular liquid"), the liquid-phase fluid is pressurized using a pump before passing through a pressure vessel. In this exemplary embodiment, the pump may be controlled by a programmable logic controller (PLC) which can utilize pressure sensors to monitor the pressure in the liquid-phase fluid and in the cell or cell stack. The PLC can preferably turn the pump on and off, thereby ensuring that the liquid-phase fluid is pressurized to and / or has a pressure comparable to the pressure of the gas and / or liquid in the cell or cell stack.

[0035] In a further exemplary embodiment where the fluid surrounding the cell stack is a liquid-phase fluid, the liquid-phase fluid in the pressure vessel is pressurized by a gas in an attached expansion vessel. Optionally, the gas may be a gas generated by the cell or cell stack, or a gas used by the cell or cell stack. In doing so, the liquid-phase fluid is pressurized to and / or has a pressure comparable to the pressure of the gas and / or liquid in the cell or cell stack (provided that if there are two or more gases in the cell stack, they are maintained at approximately equal pressures).

[0036] In one non-limiting example where the fluid surrounding the cell stack is a liquid-phase fluid, the liquid-phase fluid is water, for example, deionized water. Preferably, but not exclusively, the water entering the pressure vessel is heated by the cell stack in the pressure vessel, which may be at ambient temperature, e.g., room temperature, and at a higher operating temperature, e.g., 80°C. Preferably, in doing so, the water cools the cell stack. Preferably, as the water passes through the pressure vessel and exits it, it removes heat from the cell stack. Preferably, the removed heat is transported elsewhere so that it is released when the water cools to ambient temperature. Preferably, the flow of water through the pressure vessel is regulated to maintain the temperature of the cell stack at or near the target operating temperature. Preferably, the cell stack has low cooling requirements so that this cooling mechanism is sufficient to manage and maintain the temperature of the cell stack.

[0037] Preferably, but not exclusively, in the case of an electrosynthetic liquid gas cell or cell stack where the liquid-phase fluid surrounding the cell stack is water, the water is makeup water that is later added separately to the system to replenish the water consumed during operation. Preferably, but not exclusively, in the case of an electrical energy cell or cell stack, the water is water that is produced by the cell or cell stack during operation and previously removed separately from the cell or cell stack.

[0038] In a further exemplary embodiment where the fluid surrounding the cells or cell stack within the pressure vessel is a gaseous fluid ("annular gas"), the gaseous fluid is preferably, but not exclusively, an inert gas such as nitrogen or argon in a sufficiently pure and dry form. Preferably, but not exclusively, the annular gas passes through the space between the cells or cell stack and the pressure vessel wall continuously, continuously, or periodically, preferably slowly. Preferably, but not exclusively, the annular gas leaving the pressure vessel is monitored to detect the presence of one or more contaminating gases that may have leaked from the cells or cell stack into the annular gas, thereby alerting the balance of plant safety systems to the presence of a gas leak from the inside to the outside of the cells or cell stack. That is, optionally, the annular gas leaves the pressure vessel and the exiting annular gas is monitored to detect the presence of one or more contaminating gases. Preferably, but not exclusively, if the product of the electrochemical reaction is a gas, the product gas is monitored by the balance of plant for contamination by the inert cyclic gas described above, thereby alerting the safety system to gas leaks from the outside to the inside of the cell or cell stack. Preferably, but not exclusively, a condensate trap or similar liquid capture device is installed at the bottom of the pressure vessel or at the outlet of the cyclic gas from the pressure vessel, thereby detecting and capturing any liquid that may have leaked from the cell or cell stack into the cyclic gas. In this way, the safety system may alert to the presence of liquid leaks from the inside to the cyclic gas from the inside to the outside of the cell or stack. Furthermore, such leaks may be contained and contained within the condensate trap or liquid capture device. Optionally, the cyclic gas is the reaction gas or product gas of the electrochemical reaction.

[0039] Preferably, the cell or cell stack can withstand an internal-to-external pressure difference across its walls of less than 0.1 bar, less than 0.15 bar, less than 0.2 bar, less than 0.3 bar, less than 0.4 bar, less than 0.5 bar, less than 0.75 bar, less than 1 bar, less than 1.5 bar, less than 2 bar, less than 3 bar, less than 4 bar, less than 5 bar, less than 7.5 bar, less than 10 bar, or less than 20 bar.

[0040] Preferably, the pressure difference between the pressure of the liquid phase fluid in the operating cell or cell stack and the pressure of the gas and / or liquid is less than 0.001 bar, less than 0.002 bar, less than 0.003 bar, less than 0.005 bar, less than 0.010 bar, less than 0.020 bar, less than 0.040 bar, less than 0.050 bar, less than 0.075 bar, less than 0.100 bar, less than 0.125 bar, less than 0.150 bar, less than 0.200 bar, less than 0.300 bar, less than 0.400 bar, less than 0.500 bar, less than 0.750 bar, less than 1 bar, less than 2 bar, less than 5 bar, or less than 10 bar.

[0041] In various exemplary embodiments, the embodiments relate to a balance of plant or operating method for an electrosynthesis or electroenergy liquid gas cell or cell stack, comprising novel and / or improved means for equalizing or substantially equalizing two or more gas pressures within a cell or cell stack.

[0042] In one exemplary embodiment, a pressure equalization system is provided for the balance of a plant of electrosynthesis or electroenergy liquid gas cells or cell stacks, the system containing two or more separate and distinct gases, each in “bulk” form, each occupying a separate and distinct volume portion within the cell or cell stack.

[0043] In an example of another embodiment, the balance of plant includes a single pressure equalization tank in which the tank is partially filled with liquid. Preferably, the single pressure equalization tank has a headspace above the liquid, and the headspace is occupied by one of the gases present in bulk form within a cell or cell stack. Preferably, the gas in the headspace of the single pressure equalization tank is connected via a gas conduit to a volume section containing the corresponding bulk gas within the cell or cell stack. Preferably, but not exclusively, the gas can pass through the headspace of the single pressure equalization tank on its way to and from the volume section in the cell or cell stack containing its corresponding bulk gas. Preferably, the pressure of the gas is controlled using a back pressure valve, and the headspace of the single pressure equalization tank and the gas conduit are located between the back pressure valve and the volume section of the corresponding bulk gas within the cell or cell stack. Preferably, the pressure of each of the other bulk gases within the cell or cell stack is controlled individually by additional back pressure valves located in gas conduits through which each of these gases enters and exits the cell or cell stack separately. Preferably, the pressures of two or more separate gases, each in bulk form, within a cell or cell stack are equalized or substantially equalized by adjusting each back pressure valve relative to the others. Preferably, the headspace of a single pressure equalization tank is provided with a buffer volume that significantly facilitates the equalization or substantially equalization of the gas pressures of two or more bulk gases within a cell or cell stack. Preferably, easier, more ready, more reliable, more stable (over time), and / or more rapid equalization of the pressures of two or more bulk gases within a cell or cell stack is achieved.

[0044] In another exemplary embodiment, the balance of plant includes two or more pressure equalization tanks, each partially filled with a liquid, which may be a different liquid in each tank or the same liquid in each tank. Preferably, the headspace above the liquid in each pressure equalization tank is occupied by a different gas selected from gases present in bulk form in a cell or cell stack. Preferably, the gas in the headspace of each pressure equalization tank is connected via a gas conduit to a volume section containing the corresponding bulk gas in a cell or cell stack. Preferably, each gas may pass through the headspace of its corresponding pressure equalization tank on its way to or from its volume section in a cell or cell stack. Preferably, the pressure of each gas is controlled using a back pressure valve, and the headspace of each pressure equalization tank and its gas conduit are located between the back pressure valve and the volume section of the corresponding bulk gas in the cell or cell stack. Preferably, the pressures of each separate gas in bulk form in a cell or cell stack are equalized or substantially equalized by adjusting each back pressure valve relative to the others. Preferably, the headspace of each pressure equalization tank is provided with a buffer volume that significantly facilitates the equalization or substantially equalization of the gas pressure of the bulk gas present in the cell or cell stack. Preferably, easier, more ready, more reliable, more stable (over time), and / or more rapid equalization of the pressure of the bulk gas in the cell or cell stack is achieved.

[0045] In another exemplary embodiment, the balance of plant includes two or more pressure equalization tanks, each partially filled with a liquid, which may be a different liquid in each tank or the same liquid in each tank. Preferably, the headspace above the liquid in each pressure equalization tank is occupied by a different gas selected from gases present in bulk form in a cell or cell stack. Preferably, the gas in the headspace of each pressure equalization tank is connected via a gas conduit to a volume section containing the corresponding bulk gas in the cell or cell stack. Preferably, each corresponding bulk gas can pass through the headspace of each pressure equalization tank on its way to and from the volume section of the corresponding bulk gas in the cell or cell stack. Preferably, the pressure equalization tanks are connected to each other via liquid-filled "connecting pipes" that allow the liquid in each pressure equalization tank to move easily and quickly to the other tanks without obstruction. Preferably, the liquid moves spontaneously between the pressure equalization tanks via the connecting pipes to balance, equalize, or substantially equalize the pressure of the headspace gases in each tank. Preferably, each pressure equalization tank has a fairly clearly defined and distinct liquid level, and the liquid is in contact with its gas in the headspace of the tank. Preferably, the liquid in the pressure equalization tank has a clearly defined and essentially constant density and compressibility during operation, for example, the liquid has a substantially constant density during operation.

[0046] In all of the above embodiments of the gas pressure equalization system, - Preferably, though not exclusive, the pressure equalizing tanks are "infrastructure" tanks, meaning they are below the level of the cells or cell stack relative to gravity (i.e., positioned below, beneath, or below). Preferably, the pressure equalizing tanks are positioned or positioned so that they are completely below, beneath, or below the cells or cell stack relative to gravity. - Preferably, each of the bulk gases dissolves only slightly (i.e., moderately or partially) in the liquid in the pressure equalization tank. - Preferably, the liquid in each pressure equalization tank has a large volume relative to the volume of its gas in the cell or cell stack and the rest of the balance of plant, thereby resulting in a greater equalization of the gas pressure difference. -If the liquid in the pressure equalization tank is also a liquid electrolyte circulated in the cell or cell stack, those liquid electrolytes preferably have the same or substantially the same pressure as each of the bulk gases. That is, preferably, though not exclusive, the pressure equalization system equalizes or substantially equalizes the pressures of several separate bulk gases, as well as the pressures of one or more liquid electrolytes in the cell or cell stack.

[0047] In one exemplary embodiment, a gas equalization system for an electrosynthetic or electroenergy liquid gas cell or cell stack is provided, wherein the cell or cell stack is configured to separate and retain a first gas in bulk form within the cell or cell stack. The gas equalization system comprises a first equalization tank for at least partially containing a first liquid having a first liquid level and for partially containing a first gas in bulk form. The first gas is positioned above the first liquid level. A first gas conduit is provided for transferring the first gas in bulk form between the cell or cell stack and the first equalization tank.

[0048] In another exemplary embodiment, a gas equalization system is provided for an electrosynthetic or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a bulk form of a first gas from a bulk form of a second gas within the cell or cell stack. The gas equalization system comprises a first equalization tank for at least partially containing a first liquid having a first liquid level and for partially containing a bulk form of the first gas. The first gas is positioned above the first liquid level. A first gas conduit is provided for transferring the bulk form of the first gas between the cell or cell stack and the first equalization tank.

[0049] In another exemplary embodiment, the cell or cell stack is configured to keep the bulk form of the first gas separate from the bulk form of the second gas within the cell or cell stack, and a second pressure equalization tank is additionally provided to contain at least partially the second liquid and the second gas having a second liquid level, the second gas being positioned above the second liquid level, and the second gas including the bulk gas also present within the cell or cell stack. A second gas conduit is provided to transfer the bulk form of the second gas between the cell or cell stack and the second pressure equalization tank.

[0050] In another exemplary embodiment, a connecting pipe is provided for transferring liquid between a first pressure equalization tank and a second pressure equalization tank. The first and second pressure equalization tanks are positioned below the cell or cell stack, preferably completely below the cell or cell stack, relative to gravity.

[0051] In another exemplary embodiment, a method is provided for operating a gas pressure equalization system for an electrosynthesis or electroenergy liquid gas cell or cell stack. The method comprises operating a cell or cell stack to produce or consume a first gas, wherein the cell or cell stack is configured to keep the first gas isolated in bulk form within the cell or cell stack. The method also includes the first gas flowing in or out in bulk form to a first pressure equalization tank via a first gas conduit. The first pressure equalization tank at least partially contains a first liquid having a first liquid level, and the first gas is positioned above the first liquid level.

[0052] In another exemplary embodiment, a method is provided for operating a gas pressure equalization system for an electrosynthesis or electroenergy liquid gas cell or cell stack. The method comprises operating a cell or cell stack to produce or consume a first gas and a second gas, wherein the cell or cell stack is configured such that the first gas in bulk form remains separated from the second gas in bulk form within the cell or cell stack. The method also includes a first gas flowing in or out in bulk form to a first pressure equalization tank via a first gas conduit. The first pressure equalization tank at least partially contains a first liquid having a first liquid level, and the first gas is positioned above the first liquid level.

[0053] In another exemplary embodiment, the first gas flows in or out of a first pressure equalization tank in bulk form via a first gas conduit connected to a cell or cell stack. The first pressure equalization tank contains at least partially a first liquid having a first liquid level, and the first gas is positioned above the first liquid level. The headspace volume of the first pressure equalization tank is provided with a buffer volume to facilitate the equalization or substantial equalization of the pressure of the first gas in the cell or cell stack. Preferably, the first liquid in the first pressure equalization tank has a large volume relative to the volume of its bulk gas (first gas) in the cell or cell stack and the rest of the balance of plant, thereby allowing for the rapid equalization of even larger gas pressure differences.

[0054] In another exemplary embodiment, the method includes operating a cell or cell stack to generate or consume a first gas and a second gas, wherein the cell or cell stack is configured to keep the first gas in bulk form separated from the second gas in bulk form within the cell or cell stack. A second gas is further provided to flow in or out in bulk form to a second pressure equalization tank via a second gas conduit connected to the cell or cell stack. The second pressure equalization tank at least partially contains a second liquid having a second liquid level, and the second gas is positioned above the second liquid level. The second gas flows in or out in bulk form to the second pressure equalization tank via a second gas conduit connected to the cell or cell stack. The headspace volume of the second pressure equalization tank is provided with a buffer volume to facilitate the equalization or substantial equalization of the pressures of the first and second gases in the cell or cell stack. Preferably, the second liquid in the second pressure equalization tank has a large volume relative to its bulk gas volume in the cell or cell stack and the rest of the balance of plant, thereby resulting in rapid equalization of even larger gas pressure differences. Preferably, the first liquid in the first pressure equalization tank is the same liquid as the second liquid in the second pressure equalization tank. Optionally, the first liquid in the first pressure equalization tank may be a different liquid from the second liquid in the second pressure equalization tank.

[0055] In another exemplary embodiment, a liquid-filled connecting pipe is further provided between the pressure equalization tanks. The first / second liquid flows between the first and second pressure equalization tanks via the connecting pipe when the pressure of the first gas in the first pressure equalization tank differs from the pressure of the second gas in the second pressure equalization tank. Preferably, the connecting pipe is positioned below, preferably completely below, the first and second liquid levels during operation. Preferably, the connecting pipe allows for the transfer of the first or second liquid between the first and second pressure equalization tanks. Preferably, the pressure difference between separate gases in a cell or cell stack is compensated for by the spontaneous flow of liquid between the two pressure equalization tanks until the gas pressures are equal. Preferably, clearly defined and distinct levels of the first / second liquid in each pressure equalization tank result in accurate and rapid equalization of the gas pressure. Preferably, clearly defined and essentially constant density and compressibility of the first / second liquid in the two pressure equalization tanks result in accurate and rapid equalization of the gas pressure. Preferably, the surface area of ​​the first / second liquid is large at its interface with its corresponding gas in each equalization tank relative to the volume of its corresponding gas in the cell or cell stack and the rest of the balance of plant. Such a configuration is desirable because it minimizes system perturbations during gas pressure equalization, with the speed of the associated action.

[0056] In another exemplary embodiment relating to the use of two pressure equalization tanks with a liquid-filled connecting pipe in between, the pressures of two or more gases in an electrosynthesized or electroenergy liquid gas cell or cell stack are preferably kept equal by maintaining the liquid levels in each pressure equalization tank at the same height.

[0057] In a further exemplary embodiment relating to the use of two pressure equalization tanks, the pressures of two or more gases in an electrosynthesizing or electroenergy liquid gas cell or cell stack are preferably maintained at a constant difference by maintaining a constant height difference in the liquid levels in those pressure equalization tanks.

[0058] In various exemplary embodiments, the embodiments relate to a balance of plant or operating method for electrosynthesis or electroenergy liquid gas cells or cell stacks, equipped with novel and / or improved gas pressure control.

[0059] In one exemplary embodiment, a gas pressure control system for the balance of a plant of electrosynthesis or electroenergy liquid gas cells or cell stacks is provided, which uses two valves positioned sequentially (i.e., in series) in a gas pipe to control the gas pressure within the installed cell or cell stack. Preferably, but not exclusively, the valves are back pressure control valves. Preferably, one valve is called a “coarse” control valve and is used to make relatively large adjustments to the gas pressure. Preferably, the other valve is called a “fine” control valve and is used to make relatively small adjustments to the gas pressure. Preferably, but not exclusively, the fine control valve is positioned closer to the cell or cell stack along the gas pipe than the coarse control valve. Preferably, but not exclusively, the coarse control valve is positioned at or near the outer end of the gas pipe. Preferably, but not exclusively, a buffer volume is included between the coarse control valve and the fine control valve. Preferably, though not exclusive, the coarse control valve and the fine control valve are controlled by a programmable logic controller (PLC) that monitors at least the following locations: (1) the gas pipe between the fine control valve and the coarse control valve, (2) the gas pipe between the fine control valve and the cell or cell stack, and (3) a pressure detector / sensor positioned within the cell or cell stack.

[0060] Preferably, the gas pipe between the microcontrol valve and the cell or cell stack is connected to the pressure P within the attached cell or cell stack. stack A pressure P that is close to or the same as P fine It is controlled to have. Preferably, the gas pipe between the fine control valve and the coarse control valve is P fine Pressure P may differ slightly but not significantly. coarse It is managed to have such a pressure difference ΔP = P across the microcontrol valve. coarse -P fineIt is preferable to manage the pressure inside the gas pipe so that it becomes smaller. Preferably, the fine control valve has the property that a small pressure difference (ΔP) across it enables adjustment of a more accurate pressure P than is possible with a larger pressure difference ΔP. That is, preferably, the fine control valve can open and close in a more controlled and accurate manner with a pressure difference (ΔP) smaller than a large pressure difference across it. Preferably, the more accurate adjustment of pressure P also results in a more accurate adjustment of the pressure P inside the cell or cell stack. Preferably, although not exclusively, a buffer volume portion is included between the coarse control valve and the fine control valve, thereby providing better control of the fine control valve and thereby better control of the gas pressure inside the cell or cell stack. fine Preferably, the fine control valve has the property that a small pressure difference (ΔP) across it enables adjustment of a more accurate pressure P than is possible with a larger pressure difference ΔP. That is, preferably, the fine control valve can open and close in a more controlled and accurate manner with a pressure difference (ΔP) smaller than a large pressure difference across it. Preferably, the more accurate adjustment of pressure P fine also results in a more accurate adjustment of the pressure P inside the cell or cell stack. stack Preferably, although not exclusively, a buffer volume portion is included between the coarse control valve and the fine control valve, thereby providing better control of the fine control valve and thereby better control of the gas pressure inside the cell or cell stack.

[0061] Preferably, the pressure difference across the fine control valve, i.e., ΔP = P coarse - P fine is less than 0.001 bar, less than 0.002 bar, less than 0.003 bar, less than 0.005 bar, less than 0.010 bar, less than 0.020 bar, less than 0.040 bar, less than 0.050 bar, less than 0.075 bar, less than 0.100 bar, less than 0.125 bar, less than 0.150 bar, less than 0.200 bar, less than 0.300 bar, less than 0.400 bar, less than 0.500 bar, less than 0.750 bar, less than 1 bar, less than 2 bar, less than 5 bar, less than 10 bar, or less than 20 bar.

[0062] Preferably, P fine and P stackThe pressure difference between the two is less than 0.001 bar, less than 0.002 bar, less than 0.003 bar, less than 0.005 bar, less than 0.010 bar, less than 0.020 bar, less than 0.040 bar, less than 0.050 bar, less than 0.075 bar, less than 0.100 bar, less than 0.125 bar, less than 0.150 bar, less than 0.200 bar, less than 0.300 bar, less than 0.400 bar, less than 0.500 bar, less than 0.750 bar, less than 1 bar, less than 2 bar, less than 5 bar, less than 10 bar, or less than 20 bar.

[0063] In various exemplary embodiments, embodiments relate to a balance of plant or operating method for an electrosynthesis or electroenergy liquid gas cell or cell stack that can circulate or recirculate gas through a cell or cell stack, with the purpose of maintaining a “standby” state, also known as a “hot standby” state. The “standby” state is an operating condition or state of an electrosynthesis or electroenergy liquid gas cell or cell stack, where the cell or cell stack is disconnected from the power connection and therefore cannot perform a liquid gas reaction. However, the cell or cell stack is maintained in a physical state that allows it to start operating and perform the reaction properly immediately after the power connection is re-established. Thus, the standby state is a state that allows for the immediate start of operation of the cell or cell stack without going through the steps and processes normally required during a “startup” procedure.

[0064] In one exemplary embodiment, a balance of plant for electrosynthesis or electroenergy liquid gas cells or cell stacks is provided, having a standby state in which the gas in the cell or cell stack is optionally recirculated, either continuously or intermittently, in bulk form, from the cell or cell stack back to the cell or cell stack through a “decontamination” unit. The decontamination unit is a process engineering device that removes contaminants from the recirculating gas, and the accumulation of such contaminants over time may constitute a safety hazard or make it impossible to immediately start the cell or cell stack operational without going through the steps normally required during the “startup” procedure. In some embodiments, such contaminants may move into the gas body by “gas crossover” through separators between electrodes in the cell or cell stack. In some embodiments, the decontamination unit may include a porous packed bed of catalyst that converts contaminants in the recirculating gas passing through it into water vapor.

[0065] Preferably, but not exclusively, gas circulation from the cell or cell stack to the decontamination unit is generated at least partially by an ejector, which is a device that uses a higher-pressure fluid source (powered fluid) to generate a lower-pressure region that induces movement within the fluid. The ejector may also be called an evactor, eductor, aspirator, vacuum ejector, venturi, venturi pump, jet pump, or exhaust device. Preferably, but not exclusively, gas circulation from the decontamination unit to the cell or cell stack may be generated by a fan, blower, compressor, or similar component capable of moving the gaseous fluid. Optionally, if the cell or cell stack contains two or more separate gas flows, the balance of plant can provide two or more separate recirculation loops, each incorporating a decontamination unit suitable for the contaminants involved. In such cases, both recirculation loops can be activated if the level of contaminating gas in the gas body poses a risk to them, for example, if the power connection to the cell or cell stack is disconnected. Preferably, though not mutually exclusive, both recirculation loops are stopped when the power connection of the cell or cell stack is engaged, or when the level of contaminated gas in the gas body has decreased sufficiently.

[0066] In one example, an electrosynthesis or electroenergy liquid gas cell or cell stack is a water electrolyzer or hydrogen-oxygen fuel cell, which includes two separate bulk gas flows entering and leaving the cell or cell stack, namely a flow of oxygen and a flow of hydrogen. In a water electrolyzer or hydrogen-oxygen fuel cell cell, a “gas crossover” may occur at a fixed rate between the two gas flows, hydrogen and oxygen. Such a gas crossover can typically persist even if the power connection to the cell or cell stack is disconnected. A continuous, uncontrolled gas crossover can lead to the formation of an oxygenated body containing more than about 4% hydrogen, or a hydrogenated body containing more than about 4% oxygen, both of which constitute explosive mixtures at the normal operating temperature of 80°C. Preferably, occasional, continuous, or ongoing recirculation of the separate gases through their respective decontamination units can safely maintain each gas flow by removing contaminated oxygen from the hydrogenated body and contaminated hydrogen from the oxygenated body. Preferably, a decontamination unit that removes contaminated hydrogen from the oxygenated gaseous body during standby is a “recombiner” that converts the contaminated hydrogen into water vapor. Preferably, but not exclusively, the decontamination unit that removes contaminated oxygen from the hydrogen gas during standby is a "deoxo" unit that converts the contaminated oxygen into water vapor.

[0067] Preferably, though not exclusive, the standby state is used in a water electrolyzer or hydrogen-oxygen fuel cell during "load following" or "grid balancing" of intermittent renewable energy sources, as described below.

[0068] In various exemplary embodiments, the embodiments relate to a balance of plant or operating method for electrosynthesis or electroenergy liquid gas cells or cell stacks, comprising novel and / or improved liquid management.

[0069] In one exemplary embodiment, a balance of plant is provided for an electrosynthesis or electroenergy liquid gas cell or cell stack incorporating a liquid circulation system through the cell or cell stack, where the liquid is drawn out of the cell stack by an ejector or similar component. That is, the liquid outlet pipe of the cell or cell stack is connected to a liquid circulation tank, and the liquid is drawn out of the cell or cell stack via the liquid outlet pipe by an ejector. The liquid drawn out of the cell or cell stack may be a liquid electrolyte or a coolant. Preferably, but not exclusively, gravity can assist the ejector or similar component in drawing the liquid out of the cell or cell stack. In other examples, the liquid may be pumped out of the cell or cell stack by a pump.

[0070] Preferably, but not exclusively, the liquid circulation system may also include a liquid circulation tank into which liquid drawn out by an ejector, pump, or similar component is deposited. Preferably, but not exclusively, the liquid circulation tank is an "infrastructure" tank, i.e., it is located below (i.e., below or beneath) the level of the cells and / or cell stack relative to gravity. Preferably, the liquid circulation tank is positioned or located completely below, below, or beneath the level of the cells and / or cell stack relative to gravity. The liquid circulation tank may be partially or completely filled with liquid. Preferably, but not exclusively, the liquid circulation system may further include a pump that pumps the liquid back from the liquid circulation tank to the cells or cell stack. In other examples, the liquid may be drawn out of the liquid circulation tank by an ejector and circulated back to the cells or cell stack.

[0071] Preferably, the liquid is added to or removed from the liquid circulation system by adding or removing it from the liquid circulation tank. Preferably, but not exclusively, the liquid is added to or removed from the liquid circulation system via a liquid addition / removal port on the liquid circulation tank.

[0072] When the liquid circulation tank is completely filled with liquid, the pressure of the liquid in the tank can preferably be controlled via a pressure port in the tank, which is in contact with a pressure control device, such as an expansion tank of the type described above. Optionally, the pressure port may be the same as the liquid addition / removal port.

[0073] If the liquid circulation tank is only partially filled with liquid, the headspace above the liquid level in the tank may preferably be filled with gas. Preferably, the pressure of the liquid in the liquid circulation tank is controlled by controlling the pressure of the gas in the headspace. Optionally, the gas in the headspace may also be gas that exists in bulk form in the cell or cell stack. Optionally, the headspace may be physically connected to the inlet or outlet of its gas in the cell or cell stack, and fluid connections may be provided for the gas in the headspace and the gas in the cell or cell stack. Optionally, the pressure of the gas in the headspace may be the same as or substantially the same as the pressure in the cell or cell stack. Optionally, the partially filled liquid circulation tank may also function as a gas equalization tank along the lines described above. Optionally, the pressure of the gas in the headspace may be controlled by coarse and fine control valves positioned sequentially (in series) on the installed gas pipes, as described above.

[0074] If the cell or cell stack includes two or more separate circulating liquid flows, e.g., an anode liquid flow and a cathode liquid flow, the balance of plant may optionally include two or more separate liquid circulation systems. Such a configuration is referred herein to as a “parallel liquid circulation system”. Preferably, but not exclusively, each liquid circulation system may incorporate a separate liquid circulation tank. Preferably, but not exclusively, each tank is an “infrastructure” tank. Each of the component liquid circulation systems may preferably, but not exclusively, incorporate a separate ejector or similar component to draw liquid from the cell or cell stack. Preferably, but not exclusively, each liquid circulation system may incorporate a separate pump to pump liquid back from the tank to the cell or cell stack. Optionally, each partially filled liquid circulation tank may also function as a gas equalization tank along the lines described above. Optionally, the gas pressure in the headspace of each partially filled liquid circulation tank can be controlled by coarse and fine control valves positioned sequentially (in series) on the installed gas pipes, as described above.

[0075] If there are two liquid circulation systems, each containing a separate partially filled liquid circulation tank whose headspace is filled with a separate gas fluid-connected to the same gas in bulk form inside the cell or cell stack, then the two liquid circulation tanks can function simultaneously as pressure equalization tanks if they contain the same liquid and are equipped with a "connecting pipe" filled with the liquid of the type described above. In such a case, the two liquid circulation tanks may also serve as a pressure equalization system. Preferably, but not exclusively, the liquid circulation tank that also serves as a pressure equalization tank is an infrastructure tank positioned below (i.e., below or beneath) the level of the cell and / or cell stack relative to gravity. Preferably, the liquid circulation tank that also serves as a pressure equalization tank is positioned or placed directly below, beneath, or beneath the level of the cell and / or cell stack relative to gravity.

[0076] In an alternative example, two liquid circulation flows in a parallel liquid circulation system may optionally be combined into a single liquid flow at a point along each liquid circulation path, and then separated again into two liquid flows at another point. For example, a single ejector or similar component may optionally draw both liquid flows from the cell or cell stack, thereby combining the flows at the point where they exit the cell or cell stack. Alternatively, or additionally, the two liquid flows may be combined into a single electrolyte flow at the point where each flow accumulates in a single liquid circulation tank. Alternatively, or additionally, the two liquid flows may be drawn from two liquid circulation tanks by a single pump that combines them into one. The combined liquid flow may similarly be separated again into two flows at a point along the liquid circulation path before re-entering the cell or cell stack.

[0077] Optionally, other parts of the liquid circulation system may also be partially filled with liquid. For example, the liquid outlet pipe of a cell or cell stack may be drawn out of the cell or cell stack by an ejector and may contain a gas headspace above the liquid level. Optionally, the gas in that headspace may also be gas that is present in bulk form within the cell or cell stack. Optionally, the headspace may be physically connected to the inlet or outlet of that gas within the cell or cell stack via an orifice, valve, or similar pressure-reducing device, providing a fluid connection for the gas in the headspace and the gas within the cell or cell stack.

[0078] For example, an electrosynthesis or electroenergy liquid gas cell or cell stack is a water electrolytic cell or hydrogen-oxygen fuel cell that includes two separate liquid flows, namely an oxygen-side liquid electrolyte flow and a hydrogen-side liquid electrolyte flow.

[0079] In this example, the balance of plant comprises two separate liquid circulation systems, one for the oxygen-side liquid electrolyte flow and one for the hydrogen-side liquid electrolyte flow, and each liquid circulation system separately incorporates an ejector or similar component to draw the liquid flow from the cell or cell stack, or a pump to pressurize the liquid flow from the cell or cell stack. Preferably, but not exclusively, each liquid circulation system also incorporates a separate partially filled liquid circulation tank, the headspace of which contains a gas fluid-connected to the corresponding bulk gas in the cell or cell stack via a gas conduit. That is, the gas in the headspace of the liquid circulation tank for the oxygen-side liquid electrolyte flow is preferably, but not exclusively, oxygen fluid-connected to bulk oxygen in the cell or cell stack via a gas conduit. The gas in the headspace of the liquid circulation tank for the hydrogen-side liquid electrolyte flow is preferably, but not exclusively, hydrogen fluid-connected to bulk hydrogen in the cell or cell stack via a gas conduit. Preferably, but not exclusively, the liquid pressure in each liquid circulation tank is set by the headspace gas pressure, which is comparable to the bulk gas pressure in the cell or cell stack. Preferably, but not exclusively, the gas pressure in each liquid circulation system is equalized by the aforementioned type of pressure equalization system and controlled by a gas pressure control system using the aforementioned type of fine and coarse control valves. Preferably, but not exclusively, the two liquid circulation tanks contain the same liquid electrolyte. Preferably, but not exclusively, the two separate liquid circulation tanks are infra-tanks, i.e., they are below, below, or beneath the level of the cell or cell stack relative to gravity, preferably completely below, below, or beneath.

[0080] In another example, the oxygen and hydrogen liquid flows merge into a single liquid flow and are deposited in a single partially filled liquid circulation tank. Preferably, the single liquid-filled circulation tank has a headspace containing a gas fluidized to the corresponding bulk gas in the cell or cell stack via a gas conduit. Preferably, but not exclusively, the headspace gas is oxygen, which is fluidized to bulk oxygen in the cell or cell stack via a gas conduit. Optionally, the headspace gas is hydrogen, which is fluidized to bulk hydrogen in the cell or cell stack via a gas conduit. Preferably, but not exclusively, a single ejector or similar component draws both the oxygen and hydrogen liquid flows from the cell or cell stack, thereby combining the flows within the cell or cell stack, or at the point where they exit the cell or cell stack. Alternatively or additionally, the oxygen and hydrogen liquid flows are drawn from a single liquid circulation tank by a single pump. The combined liquid flows may be separated again into two flows at some point in the liquid circulation path before or after re-entering the cell or cell stack.

[0081] In further examples, an electrosynthesis or electroenergy liquid gas cell or cell stack is a water electrolytic cell or hydrogen-oxygen fuel cell containing a single liquid flow, either an aqueous oxygen-side liquid flow or an aqueous hydrogen-side liquid flow. Preferably, the single liquid flow is deposited in a single partially filled liquid circulation tank. Preferably, the single liquid-filled circulation tank has a headspace containing a gas fluidized to the corresponding bulk gas in the cell or cell stack via a gas conduit. Preferably, but not exclusively, the headspace gas is oxygen, which is fluidized to bulk oxygen in the cell or cell stack via a gas conduit. Optionally, the headspace gas is hydrogen, which is fluidized to bulk hydrogen in the cell or cell stack via a gas conduit. Preferably, but not exclusively, a single ejector or similar component draws the liquid flow out of the cell or cell stack. Alternatively or additionally, the single liquid flow is drawn out of the single liquid circulation tank by a single pump.

[0082] Optionally, in the case of a water electrolytic cell, the water consumed by the reaction is replenished by adding "makeup" water to one or both of the liquid circulation tanks present. Optionally, the makeup water is deionized water that has passed between the cell stack and the wall of the pressure vessel surrounding it, as described above, before being added to the liquid circulation tanks. The pressure vessel preferably surrounds the cell or cell stack. Optionally, in the case of a fuel cell, the water produced by the reaction is removed from one or both of the liquid circulation systems by removing it from one or both of the liquid circulation tanks. The removal process may include, for example, the condensation of water vapor from the headspace gas, and the resulting liquid water is removed from the liquid circulation tanks. Alternatively, any other removal process may be used.

[0083] In various exemplary embodiments, the embodiments relate to a balance of plant or operating method for electrosynthesis or electroenergy liquid gas cells or cell stacks, equipped with novel and / or improved cell or cell stack cooling management. Such cooling systems may be particularly useful for cells or cell stacks with relatively small cooling requirements.

[0084] In one example, as described above, a cell or cell stack is provided which is cooled by passing an annular liquid, which is an annular cooling water, through the volume between the outer wall of the cell or cell stack and the wall of the pressure vessel surrounding it. In another example, a cell or cell stack is provided which has the liquid circulation system of the above type, and the cell or cell stack is cooled by cooling the liquid in a liquid circulation tank. The liquid in the liquid circulation tank can be cooled via a cooling system incorporated into the tank. Such a cooling system can use a circulating cooling fluid. Alternatively, if the liquid in the liquid circulation tank is water, the water in the liquid circulation tank may be cooled by adding cooling water to it. In a further example, the liquid in the liquid circulation tank can be cooled by condensing water vapor from the gas in the tank and removing the resulting liquid water from the tank, as described above.

[0085] In exemplary embodiments, the electrosynthesis or electroenergy liquid gas cell or cell stack is a water electrolytic cell or hydrogen-oxygen fuel cell that can include a single liquid flow or two separate liquid flows, namely an oxygen-side liquid electrolyte flow and / or a hydrogen-side liquid electrolyte flow. In the case of a water electrolytic cell, the cell or cell stack is preferably cooled, but not exclusively, by passing makeup water at ambient temperature between the cell or cell stack and the wall of the pressure vessel around it, as described above, and then by adding the makeup water to one or both of the liquid circulation tanks to replenish the water consumed in the reaction as described above. Optionally, the makeup water may be cooled between its outlet from the pressure vessel and its addition to the liquid circulation tanks. In the case of a hydrogen-oxygen fuel cell, the cell or cell stack is preferably cooled, but not exclusively, by condensing water vapor in one or both of the liquid circulation tanks, as described above, and then by removing the resulting liquid water from the tanks. Optionally, the removed water may be further cooled after leaving the liquid circulation tanks and then pass through the volume between the cell or cell stack and the wall of the pressure vessel around it, as described above.

[0086] In further exemplary embodiments, for example, one or more “phase change tubes” of a type commonly used in computer laptops may be placed in the above-mentioned liquid circulation tank to cool the circulating liquid therein, or may be used to cool the liquid passing along the liquid circulation tube.

[0087] In various exemplary embodiments, the embodiments relate to a balance of plant or operating method for electrosynthesis or electroenergy liquid gas cells or cell stacks, comprising novel and / or improved monitoring and control of the cell state.

[0088] In one exemplary embodiment, each cell in a cell stack includes a computer chip or one or more computer chips that communicate wirelessly with all other chips in other cells, or are connected to all other chips in other cells via a single common electrical connection or wire, thereby communicating with a PLC in the balance of plant, and one or more computer chips associated with each computer chip or cell transmit voltage and / or other information from that cell to the PLC. In this way, the need for multiple wires connecting the PLC to different cells present is avoided. This makes it practically possible for the PLC in the balance of plant to monitor the status of a large number of cells in an industrial cell stack, including, for example, 50, 100, 150, 200, 300, 400, 500 or more cells, in real time. Such monitoring can enable the PLC to better manage electrosynthesizing or electroenergy liquid gas cells or cell stacks.

[0089] Preferably, but not exclusively, a computer chip or one or more computer chips are embedded in each cell, for example, within the polymer cell frame of each cell. Preferably, but not exclusively, electrical connections or wires are similarly embedded in each cell, for example, within the polymer cell frame of each cell. Various different communication protocols can be used. In one exemplary protocol, each chip in each cell is programmed to repeatedly transmit its cell information to the PLC wirelessly or along a single common electrical connection or wire at different times, thereby enabling the PLC to receive the data and match the data with the location of the chip that transmitted it. In another exemplary protocol, each chip, or one or more computer chips associated with a cell, may transmit its information wirelessly or along a single common electrical connection or wire only when polled by the PLC, and the PLC may transmit a signal to this effect along the single common electrical connection or wire. Numerous other techniques may be provided for transmitting cell information to the PLC, and it should be understood that all such techniques are included within the scope of this specification.

[0090] In various exemplary embodiments, the embodiments relate to a balance of plant or operating method for electrosynthesis or electroenergy liquid gas cells or cell stacks, comprising novel and / or improved cell stack configurations and controls. In one example, multiple cell stacks are assembled into an "array" sharing a common manifold, which stores multiple separate gas and liquid flows from the attached cell stacks into a single separate external gas and liquid flow.

[0091] In one exemplary embodiment, cell stacks, each contained within a pressure vessel, i.e., cell or cell stacks surrounded by a pressure vessel, are mounted on a common manifold element that connects to the individual liquid and gas inlets / outlets of each mounted cell stack, with each manifold element accumulating the individual gas and liquid lines of its mounted cell stack into a single, overall separate external liquid and gas inlet / outlet. In this way, many individual liquid and gas inlets / outlets within a mounted cell stack can be reduced to a few overall separate external liquid and gas inlets / outlets. Furthermore, the manifold element can also incorporate or house wiring that provides cumulative or separate power connections to each of the mounted cell stacks. Preferably, but not exclusively, such an array includes cell stacks within a pressure vessel, with each end of each cell stack mounted on a different manifold element. When separate cables are used for each power connection in such an array, each cell stack is preferably, but not exclusively, electrically activated independently. When powering multiple cell stacks within such an array using a single cable, all connected cells can be electrically powered simultaneously.

[0092] In one example, the electrosynthesis or electroenergy liquid gas cell stack is that of a water electrolytic cell or hydrogen-oxygen fuel cell, comprising one or two liquid flows, namely an oxygen-side liquid electrolyte flow and / or a hydrogen-side liquid electrolyte flow. Preferably, but not exclusively, multiple cell stacks are arranged between two manifold elements, each connected to a different end of the cell stack. Preferably, but not exclusively, such a configuration provides a single global external hydrogen gas inlet on one manifold and a single global external hydrogen gas outlet on the other manifold, as well as a single global external oxygen gas inlet on one manifold and a single global external oxygen gas outlet on the other manifold. Preferably, but not exclusively, such an arranged water electrolytic cell or hydrogen-oxygen fuel cell may be configured to maintain a "standby" state by recirculating either or both of bulk forms of hydrogen and oxygen within the arranged cell stacks via the single global external hydrogen inlet and outlet, and / or single global external oxygen inlet and outlet, respectively, as described above.

[0093] Preferably, but not exclusively, the manifold elements of such a cell stack array further include a single global external oxygen-side liquid electrolyte inlet and a single global external oxygen-side liquid electrolyte outlet, as well as a single global external hydrogen-side liquid electrolyte inlet and a single global external hydrogen-side liquid electrolyte outlet. Preferably, but not exclusively, such an arranged water electrolytic cell or hydrogen-oxygen fuel cell may be configured to circulate the oxygen-side liquid electrolyte and / or hydrogen-side liquid electrolyte through the single global external oxygen-side liquid electrolyte inlet and outlet, and / or the single global external hydrogen-side liquid electrolyte inlet and outlet, respectively, as described herein.

[0094] Preferably, but not exclusively, each cell stack in this arrangement is separately electrically connected to a single power element capable of optional bidirectional power management, such as an inverter that can supply power to the cell stack (when operating as a water electrolyzer) or transmit power from the cell stack (when operating as a hydrogen-oxygen fuel cell). Preferably, but not exclusively, each such power element is managed by a PLC in the balance of plant, thereby enabling a rapid change in direction of operation.

[0095] Preferably, these features, in combination with other features described in the previous paragraphs, provide a balanced plant that enables bidirectional operation of the cell stack arranged as either a water electrolyzer or a hydrogen-oxygen fuel cell system, i.e., as a regenerative fuel cell-electrolyzer.

[0096] Embodiments further relate to manifold elements suitable for manifolding cell stacks into an array. Preferably, the manifold element can form either a parallel or series connection of separate gas and liquid flows of the attached cell stacks. Preferably, the manifold element may be composed of polymer material, fiber or filler-reinforced polymer material, composite material, metal, metal alloy, or other material. Preferably, the manifold element can be manufactured by machining, 3D printing, molding including but not limited to injection molding, or other manufacturing techniques. Optionally, the manifold element can be prefabricated by assembling and fixing together “manifold sub-elements,” which may in some cases be attached to only a single cell stack. For example, techniques such as those taught in U.S. Patent No. 5,405,528, filed April 19, 1991, “Modular Microporous Filter Assemblies,” which describes an assembly of manifold sub-elements titled “symmetrical headers,” thereby creating a manifold element for a filter system.

[0097] Embodiments further relate to combining cell stack arrays into larger arrays, which are referred to herein as “3D arrays.” Preferably, but not exclusively, cell stacks arranged as described above can be combined with other arrays of similar cell stacks to further store distinct liquid and gas flows in a larger 3D array of cell stacks. Such a 3D array of cell stacks stores multiple distinct gas and liquid flows of component arrays without using common manifold elements to connect the arrays.

[0098] In various exemplary embodiments, the embodiments relate to a balance of plant or operating method for electrosynthesis or electroenergy liquid gas cells or cell stacks having novel and / or improved capabilities to “load-follow” intermittent renewable energy sources or to “grid-balance” a power grid supplied by intermittent renewable energy sources. “Load-following” refers to the phenomenon in which an electrosynthesis or electroenergy cell or cell stack receives power from a renewable energy source whose energy output changes over time and requires a constant change in the rate of electrical operation of the cell or cell stack. “Grid-balancing” refers to the phenomenon in which an electroenergy or electrosynthesis cell or cell stack transmits power to a power grid connected to a renewable energy source whose energy output changes over time and requires a constant change in the rate at which the cell or cell stack transmits energy to the grid.

[0099] In one example, load following or grid balancing is preferably achieved by systematically disconnecting (and, if necessary, putting into standby mode) the power connections of individual cell stacks or sets of cell stacks within an array, or by engaging (and, if necessary, disengaging) the power connections.

[0100] In another example, load following or grid balancing is preferably achieved by systematically disconnecting (and, if necessary, putting into standby mode) or engaging (and, if necessary, disengaging) the power connections of individual arrays or sets of arrays within a 3D array of cell stacks.

[0101] In further examples, the electrosynthesis or electroenergy liquid gas cell stacks used for load following or grid balancing are water electrolyzers or hydrogen-oxygen fuel cells. Optionally, the cell stack and associated balance of plant may operate as either a water electrolyzer or a hydrogen-oxygen fuel cell, i.e., a regenerative fuel cell-electrolyzer.

[0102] Electrosynthetic liquid gas cells or cell stacks having the above characteristics include, but are not limited to, the following types of cells: (i) water electrolytic cells, (ii) chlor-alkali electrolytic cells, (iii) cells for ammonia production, or (iv) CO2 electrolytic cells including composite carbon capture and CO2 electrolytic cells.

[0103] Electrical energy liquid gas cells or cell stacks having the above characteristics include, but are not limited to, the following types of cells: (i) hydrogen-oxygen fuel cells including polymer electrolyte membrane (PEM) fuel cells or alkaline fuel cells; (ii) direct alcohol fuel cells including direct methanol or direct ethanol fuel cells; (iii) phosphoric acid fuel cells; or (iv) ammonia fuel cells.

[0104] Herein, exemplary embodiments will be described, merely as non-limiting examples, with reference to the accompanying drawings. Various exemplary embodiments will become apparent from the following description, given merely as examples, of at least one preferred but non-limiting embodiment described in relation to the accompanying drawings. [Brief explanation of the drawing]

[0105] [Figure 1]A schematic example of a conventional electrolytic cell stack and its balance of plant is shown. [Figure 2] A schematic example of a conventional electrolytic cell stack and its balance of plant in which bulk gas is directly generated within the electrolytic cell is shown. [Figure 3] A schematic diagram illustrates an exemplary electrosynthesis or electroenergy liquid gas cell stack surrounded by a liquid within a pressure vessel. [Figure 4] A schematic diagram illustrates an exemplary electrosynthesis or electroenergy liquid gas cell stack surrounded by liquid within a pressure vessel, which includes an expansion tank. [Figure 5] A schematic diagram illustrates an exemplary gas pressure equalization system in which a single tank is used for pressure equalization. [Figure 6] Another exemplary gas pressure equalization system in which multiple tanks are used for pressure equalization is schematically shown. [Figure 7] Another exemplary gas pressure equalization system is schematically shown, in which multiple tanks are used for pressure equalization along with connecting pipes. [Figure 8] Another exemplary gas pressure equalization system with gas pressure control and management system is schematically shown. [Figure 9] A schematic diagram of an exemplary gas recirculation system is shown. [Figure 10] A schematic diagram of an exemplary liquid circulation system is shown. [Figure 11] A schematic diagram illustrates the combination of an exemplary liquid circulation system and an exemplary gas pressure control and management system. [Figure 12] Figure 10 schematically shows the interface between the liquid circulation system and the gas pressure control and management system. [Figure 13] A schematic diagram illustrates an exemplary liquid circulation system and an exemplary gas pressure control and management system combination in a water electrolytic cell or hydrogen-oxygen fuel cell. [Figure 14] An exemplary array of electrosynthetic or electroenergy liquid gas cell stacks is shown. [Figure 15] An example of a "manifold sub-element" is shown. [Modes for carrying out the invention]

[0106] The following modes, features, or embodiments, given only as examples, are described to provide a more precise understanding of the subject matter of one or more preferred embodiments.

[0107] definition "Reactants" are chemical substances consumed during an electrochemical reaction.

[0108] "Products" are chemical substances that are generated during an electrochemical reaction.

[0109] A "liquid electrolyte" is a liquid containing dissolved ions that have the ability to conduct electricity.

[0110] "Room temperature" is defined here as 21°C.

[0111] An "electric energy cell" is an electrochemical cell that generates electricity continuously or sustainably over an indefinite period during operation for use outside the cell. An electric energy cell may require a constant external supply of reactants during operation. The products of the electrochemical reaction may also be removed from such a cell at all times during operation.

[0112] An "electrosynthesis cell" is an electrochemical cell that, for use outside the cell, continuously or indefinitely converts one or more reactants into products during operation. The reactants or products may be in gaseous, liquid, or solid form. An electrosynthesis cell requires a constant supply of reactants and a constant removal of products during operation. Generally, an electrosynthesis cell may also require a constant input of electrical energy during operation.

[0113] Unlike other types of electrochemical cells such as batteries and sensors, electrosynthesis and electroenergy cells do not incorporate all / some of the reactants necessary for their operation into the cell body, nor do they incorporate all / some of the products they generate during operation into the cell body. These are instead continuously brought in from the cell during operation or removed from the outside of the cell. For example, an electrosynthesis cell is distinguished from a galvanic cell in that it stores its reactants and products within the cell body. Similarly, some electrochemical sensors may consume reactants and produce a limited amount of products during sensing operation, but all / some of these are stored within the cell body itself.

[0114] A "liquid gas" cell is an electrochemical cell having at least one liquid-phase reactant or product and at least one gas-phase reactant or product. An electrosynthesis cell or electrical energy cell may also be a liquid gas cell. An example of an electrosynthesis liquid gas cell is a water electrolysis cell that converts liquid-phase water into hydrogen gas at the cathode and oxygen gas at the anode. An example of an electrical energy liquid gas cell is a hydrogen-oxygen fuel cell that converts gaseous hydrogen and gaseous oxygen into liquid-phase water.

[0115] "Electrode separator," "separator," "separator membrane," or "separator ionomer" as used herein refers to an electrically insulating material placed between two electrodes of an electrosynthesis or electrical energy cell. The purpose of such a material includes (i) preventing short circuits from occurring between the two electrodes, and (ii) minimizing the movement of gas from one electrode or half-cell (one side of the separator) to the other. A specific example of an electrode separator is a "porous capillary separator," also known as a "porous capillary spacer," which is defined in International Publication Nos. 2022056603, 2022056604, 2022056605, and 2022056606, which are incorporated herein by reference.

[0116] The term "gas crossover" is defined herein as the phenomenon in which a gas present in one electrode or half-cell moves across an inter-electrode separator to another electrode or half-cell within an electrosynthesis or electrical energy cell. In water electrolyzers or hydrogen-oxygen fuel cells, such movement can constitute a safety hazard, for example, if one gas is hydrogen and the other gas is oxygen. A mixture of more than about 4% oxygen in a hydrogen body, or more than about 4% hydrogen in an oxygen body, can constitute an explosive mixture that poses a safety hazard at 80°C.

[0117] A “two-phase” mixture is defined herein as a mixture of gaseous and liquid phase substances in the form of a “foam” or “bubble” type mixture of a mixed gaseous and liquid phase substance. Such a “two-phase” mixture may also be called a “liquid-gas” mixture or a “two-phase liquid-gas” mixture. The mixed two-phase mixture may be separated in a separation tank or engineering structure specially designed to allow such a two-phase liquid-gas mixture to be fractionated into separate gaseous and liquid phases.

[0118] A “single-phase” or “bulk” substance is defined herein as a substance that is substantially single-phase. For example, reactants provided substantially in the gas phase, or products produced substantially in the gas phase, are called “bulk gas” reactants or products, and reactants provided substantially in the liquid phase, or products produced substantially in the liquid phase, are called “bulk liquid” reactants or products.

[0119] The "energy efficiency" of an electrosynthesis cell or system is defined as the net energy present in a single unit output of a chemical product divided by the net energy consumed by the cell or system to produce the same unit output of the chemical product, and is expressed as a percentage. In this specification, the "energy efficiency" of an electrical energy cell or system is defined as the energy produced by the cell or system per unit time divided by the maximum theoretical energy that can be produced by the cell or system per unit time, expressed as a percentage.

[0120] A "cell stack" is defined as an assembly of two or more electrocombination cells or electrical energy cells, where the cells are stacked adjacent to each other or in contact with each other along a single-dimensional axis.

[0121] The cell stack can take the form of a “filter press” configuration, defined as a filter press cell stack, where the cells are substantially flat and are compressed between end plates during their assembly and / or operation.

[0122] A "gas conduit" is defined as a conduit, tube, pipe, or chamber that transports bulk gases, such as bulk gas reactants or products of electrochemical reactions.

[0123] A "header" is a channel, tube, pipe, chamber, conduit, or trough within a cell stack, formed by the combination of orifices of individual cells within the cell stack, for transporting fluid through the length of the cell stack.

[0124] A "manifold" is one or more pipes, tubes, chambers, conduits, or channels having multiple openings for transporting fluid. A header in a cell stack may also be a manifold.

[0125] The "Supra" components of a balance of plant are components positioned above the level of the cells and / or cell stacks. For example, a "Supra" tank is a tank that is positioned above the level of the cells and / or cell stacks with respect to the direction of gravity.

[0126] The "infrastructure" components of a balance of plant are those located below the level of the cells and / or cell stacks. For example, an "infrastructure" tank is a tank located below (i.e., below or beneath) the level of the cells and / or cell stacks with respect to the direction of gravity.

[0127] A "cyclic liquid" is defined as a liquid surrounding an electrosynthesis or electroenergy liquid gas cell or cell stack incorporated into or contained within a pressure vessel.

[0128] An annular gas is defined as a gas surrounding an electrosynthetic or electroenergy liquid gas cell or cell stack incorporated into or contained within a pressure vessel.

[0129] A "liquid capture device" is an engineering component that removes liquid-phase material from a gas-phase flow. Examples of liquid capture devices include, but are not limited to, liquid condensate traps, condensers and droplet condensers, and other liquid condensing devices.

[0130] A "connecting pipe" is defined here as a liquid-filling pipe that connects two or more pressure equalization tanks and facilitates the movement of liquid between two or more pressure equalization tanks during gas pressure equalization.

[0131] An "ejector" is a device that uses a higher-pressure fluid source (power fluid) to create a lower-pressure region, where the pressure is relative to the outlet or discharge port. Such a device can be used to pump fluid from the lower-pressure region to the outlet. The power fluid is accelerated through an orifice or nozzle, and then some of its momentum is transferred to the aspirated fluid as the two flows mix within the device. The outlet of the ejector generally includes a diffuser to recover some of the kinetic energy into fluid pressure. There are many variations and applications of these types of devices, which may also be known by terms or combinations of terms including, but not limited to, evactors, eductors, aspirators, vacuum ejectors, venturis, venturi pumps, jet pumps, or exhaust devices.

[0132] The “standby” state is an operating state or condition of an electrosynthesis or electroenergy liquid gas cell or cell stack. A cell or cell stack in the “standby” state is disconnected from the power connection and therefore cannot perform liquid gas reactions, but the cell or cell stack can immediately start operating and perform reactions and produce usable products once the power connection is established. In other words, a cell or cell stack in “standby” is ready to start operating without going through the steps and processes normally included in the “startup” procedure. If a cell or cell stack is operating and then placed in the “standby” state by disconnecting the power connection, the “standby” state allows for the immediate restart of the cell or cell stack without going through the steps and processes normally included in the startup procedure. Physical conditions that need to be maintained during “standby” may include, for example, minimum temperature, minimum pressure, minimum level of gas or liquid purity, or other physical conditions, or combinations of physical conditions.

[0133] The "startup" procedure is a series of steps that may be required to bring an electrosynthetic or electroenergy liquid gas cell or cell stack from its dormant state to full operation. Such steps may include (i) removing any inert gas (also known as purge gas) that may be present in the cell or cell stack when it is at rest; (ii) raising the cell or cell stack from ambient temperature or near ambient temperature to its operating temperature; and / or (iii) raising the cell or cell stack from atmospheric pressure or near atmospheric pressure to its operating pressure.

[0134] A “shutdown” procedure is a set of steps that may be required to bring an electrosynthetic or electroenergy liquid gas cell or cell stack from full operation to its dormant state. Such steps may include (i) filling the cell or cell stack with an inert gas (also known as “purging” the cell or cell stack), (ii) lowering the cell or cell stack from its operating temperature to ambient temperature or near ambient temperature, and / or (iii) lowering the cell or cell stack from its operating pressure to atmospheric pressure or near atmospheric pressure.

[0135] The "e-stop" procedure, also known as the "emergency stop" procedure, is an accelerated, rapid shutdown procedure initiated by the control system as a result of an emergency or potential emergency, usually involving the implementation of additional safety measures.

[0136] A "sensor" is a device that detects or measures physical characteristics and reports them to a control system, such as a programmable logic controller (PLC) that manages the balance of a plant.

[0137] A "decontamination unit" is a process engineering device that removes contaminants from a gas flow passing through it. Specific examples of decontamination units include a "recombiner" (to remove contaminated hydrogen from an oxygen flow by "recombining" hydrogen with oxygen in water) and a "deoxo" unit (to remove contaminated oxygen from a hydrogen flow). A decontamination unit may include a catalyst-filled bed through which the gas passes.

[0138] A "pressure reduction device" is a device that, when present in a pipe, causes a pressure change or pressure difference from one end to the other. Examples of pressure reduction devices include an "orifice," which is a small opening through which the flow of gas or liquid is restricted; a "restrictor," which is a narrow tube with many sharp bends, each of which generates a pressure drop as gas or liquid flows through it; and a valve, which can have a variablely small opening.

[0139] A “parallel liquid circulation system” for a cell or cell stack includes two separate liquid circulation systems in at least several parts outside the cell or cell stack.

[0140] A programmable logic controller (PLC) is an industrial computer designed for the automated control of operational and / or safety processes in the balance of a plant, including the control of process engineering devices such as valves, pumps, sensors, power devices, safety devices, water distribution devices, cooling devices, and any other types of machinery or devices present. A PLC can typically manage process variables such as pressure and temperature, as well as operational steps such as "start," "shutdown," "normal operation," "standby," "process fault diagnosis," "process fault resolution," "emergency stop," or any other necessary activities. Generally, a PLC must be highly reliable, easy to program, and capable of diagnosing and responding to process faults. PLCs are sometimes also called programmable controllers.

[0141] A “computer chip” or “chip” is an integrated circuit or small wafer made of semiconductor material in which an integrated circuit is embedded, and which can perform calculation instructions, including performing measurements and transmitting the obtained measurement information to a PLC attached via an electrical connection or wire.

[0142] A "manifold element" is a structure comprising a number of pipes, tubes, chambers, conduits, or channels for transporting separate fluids, each of which is configured to be fluidly connected to a corresponding inlet / outlet for separate fluids in a number of mounted cell stacks.

[0143] A "manifold sub-element" is a structure that, when correctly assembled with other manifold sub-elements, creates a manifold element. Some manifold sub-elements may only be able to be attached to one cell stack.

[0144] An "array" is a collection of two or more cell stacks that are connected via one or more manifold elements and operate together.

[0145] A "3D array" is a collection of two or more arrays, the individual arrays that make up the array, which do not share manifold elements with each other, but are still connected via piping and / or wiring and / or a common management / control system and operate together, or share a common decentralized balance of plant components (e.g., a water supply or cooling system).

[0146] "Load following" is a phenomenon in which the power consumption rate by electrosynthesis or electrical energy cells or cell stacks changes to match the power supplied by renewable energy sources whose energy output changes over time.

[0147] "Grid balancing" is a phenomenon in which the rate at which electrical energy, electrocombined cells, or cell stacks transmit power to the power grid changes in order to balance the total power available on the grid when power is supplied by renewable energy sources whose energy output changes over time.

[0148] Explanation and definition of the term "balance of plants" To clarify and define what the balance of plant is, Figure 1 (prior art) schematically shows the key components of a typical commercial alkaline water electrolytic cell serving as an illustrative example of an electrosynthetic liquid gas cell. The electrolytic cell uses electrical energy to convert liquid water into hydrogen and oxygen gases.

[0149] In most electrosynthetic liquid gas cells, the gaseous material within the cell is in a "two-phase" form, mixed with the liquid material (e.g., as gas bubbles in the liquid-phase reactant). This requires separation of the two phases, which is typically done using a balance-of-plant tank or engineering structure that separates such a two-phase mixture into separate gas and liquid phases. This is also true of the example shown in Figure 1.

[0150] The electrolytic cell in Figure 1 comprises a cell stack 10 (shown within the dashed box in Figure 1) and its balance of plant 20 (all outside the dashed box in Figure 1).

[0151] The cell stack 10, exemplarily, comprises five cells, each cell having an anode electrode (referred to as the "+" electrode, where oxygen (O2) gas is produced in the form of oxygen bubbles in the liquid electrolyte) and a cathode electrode (referred to as the "-" electrode, where hydrogen (H2) gas is produced in the form of hydrogen bubbles in the liquid electrolyte) separated by an interelectrode membrane / ionomer separator (referred to as "M") in Figure 1. The interelectrode membrane / ionomer separator ("M") divides each cell into two half-cells, an anode half-cell and a cathode half-cell. The cells are filled with a conductive liquid-phase aqueous electrolyte called the "anodic solution" (liquid electrolyte in the anode half-cell) and the "cathode solution" (liquid electrolyte in the cathode half-cell). Thus, in an aqueous electrolytic cell, the anode solution is the oxygen-side liquid electrolyte and the cathode solution is the hydrogen-side liquid electrolyte. (In a hydrogen-oxygen fuel cell, which converts hydrogen and oxygen gases into water while generating electrical energy, the anode liquid is the hydrogen-side liquid electrolyte, and the cathode liquid is the oxygen-side liquid electrolyte.)

[0152] The lower dashed box in Figure 1 schematically labels the electrodes in the upper dashed box and shows the voltages that can be applied to each electrode in the cell stack 10 when 10V is applied to the external electrical terminals indicated as "+" and "-" at each end of the cell stack 10 in Figure 1. The applied voltage causes current to flow through the cell, and the water in the cell is split into oxygen (O2) gas bubbles at the anode and hydrogen (H2) gas at the cathode.

[0153] A balance of plant is a process engineering system or apparatus around a cell stack that supports and manages the cell stack. In the example in Figure 1, the balance of plant includes a pump 30 that pumps liquid electrolyte in direction 32 along an "anode liquid pipe" 31 and directs the pumped flow to a junction 33 that runs in parallel through all of the anode half-cells. The mixture of oxygen (O2) bubbles and anode liquid in each anode half-cell is then carried along an anode liquid pipe 34 to an "oxygen separator tank" 35, where the bubbles are separated from the liquid anode liquid 35b, forming bulk oxygen gas 35a at the top of the tank 35. The bubble-free liquid anode liquid at the bottom of the tank is pumped back to the anode half-cell cells via the anode liquid pipe 31, while the "bulk" oxygen gas 35a separated from the top of the tank 35 passes through a scrubber 36, after which the oxygen gas is released at an outlet 37.

[0154] The hydrogen gas generated in the cathodes within the cell stack 10 is similarly collected and separated by the balance of plant. In this process, pump 40 pumps the liquid electrolyte in direction 42 along the "cathode liquid tube" 41, creating a junction 43 that directs the pumped flow in parallel through all of the cathode half-cells. The mixture of hydrogen (H2) bubbles and cathode liquid in each anode half-cell is then carried along the cathode liquid tube 44 to the "hydrogen separator tank" 45, where the bubbles are separated from the liquid cathode liquid, forming bulk hydrogen gas 45a at the top of the tank 45. The bubble-free liquid cathode liquid 45b at the bottom of the tank 45 is pumped back through the cathode half-cell cells via the cathode liquid tube 41, while the hydrogen gas 45a separated from the top of the tank 45 passes through the scrubber 46, after which the hydrogen gas is released at the outlet 47. Separator tanks 35 and 45 are positioned above the cell stack to avoid the risk of a "gas lock" forming somewhere within the liquid circulation system and the gas becoming trapped in the liquid circulation piping. Bubbles also tend to rise in the liquid medium (due to their buoyancy), which means it makes sense to position the gas tanks into which the gas is transported above the cells or cell stack. In other words, separator tanks 35 and 45 are "supra" tanks, positioned above the level of the cells and cell stack.

[0155] It should be noted that the tubes through which the liquid electrolyte flows, i.e., tubes 31, 34, 43, and 44, may be partially incorporated into the cell stack in the form of headers and / or manifolds that are physically positioned within the cell stack. In this case, the portion that is physically within the cell stack is considered here to be part of the cell stack, and the portion that is physically outside the cell stack is considered to be part of the balance of plant.

[0156] Since water electrolytic cells typically generate excess heat, a liquid-cooled chiller 48 can be used to drive a heat exchanger 49 that extracts heat from, for example, the cathode liquid tube 41.

[0157] During operation, it is necessary to replenish the water consumed in the cell stack 10 to generate hydrogen and oxygen. This is done by a pump 50 that pressurizes "makeup" water 51 through water replenishment pipes 52 in directions 53 and 54, respectively. The makeup water 51 is typically added to scrubbers 36 and 46, respectively, via valves indicated as "V" in Figure 1, from which the makeup water 51 drips into liquid bodies 35b and 45b in separator tanks 35 and 45, respectively.

[0158] The operation of valve "V," as well as the power supplies attached to the "+" and "-" terminals at the ends of pumps 30, 40, and 50, chiller 48, and cell stack 10, and other components in the balance of plant not shown in Figure 1, such as flow, temperature, and pressure sensors, is typically managed by a computerized automated control system in the form of at least one programmable logic controller (PLC), which also forms part of the balance of plant. It is crucial that the process engineering configuration of the balance of plant components and system architecture provides efficient, reliable, and safe automated operation when controlled by one or more PLCs.

[0159] The electrolytic cell in Figure 1 may be configured to operate under pressure. That is, the electrolytic cell can output the generated hydrogen and oxygen at a high pressure, for example, 1 bar higher than atmospheric pressure. This may be useful for applications requiring pressurized hydrogen. To generate such pressurized gas, the cell stack 10 is typically designed to contain and maintain additional pressure within the cell stack. In such a case, the balance of plant 20 must also necessarily be designed to limit and maintain the required pressure. That is, the tubing, tanks, pumps, valves, and other components of the balance of plant must be able to handle the required pressure.

[0160] A key challenge in the above type of system is to precisely balance the pressures of the hydrogen and oxygen produced, especially under pressure, at all times during operation. Any imbalance between the pressure of oxygen gas 35a in separator tank 35 and scrubber 36 and the pressure of hydrogen gas 45a in separator tank 45 and scrubber 46 is transmitted to each half-cell of the cell stack 10 via adjacent columns of liquid anode and cathode liquids in tubes 31 and 34 (anode liquid) or tubes 41 and 44 (cathode liquid), respectively. A large pressure imbalance on opposite sides of the interelectrode membrane / ionomer separator ("M" in Figure 1) within each cell of the cell stack 10 can blow out or tear the separator, or destroy or damage the electrolytic cell. Even smaller, short-lived, transient (temporal) pressure imbalances between the anode and cathode liquids on either side of each interelectrode membrane / ionomer separator increase the cell's "gas crossover," where O2 or H2 gas passes through the interelectrode membrane / ionomer separator ("M" in Figure 1) and mixes with the gas produced on the other side. Since oxygen containing more than approximately 4% hydrogen, or hydrogen containing more than approximately 4% oxygen, is an explosive mixture at the normal operating temperature of 80°C, such "gas crossovers" constitute a significant safety problem in electrolytic cells. Commercial electrolytic cells typically automatically perform an "emergency stop" shutdown procedure if the proportion of O2 in the H2 stream, or H2 in the O2 stream, exceeds 2%. Therefore, it is essential to always minimize the pressure difference between hydrogen and oxygen gases in the individual cells of the cell stack 10, as well as in the balance of plant during operation.

[0161] What makes pressure control and equalization particularly difficult is the fact that gas separation tanks 35 and 45 may not typically have a clearly defined liquid level within them. The boundary between the liquid (35b / 45b) and gas (35a / 45a) in these tanks is occupied by a mixed two-phase "foam" or "bubble," which includes disordered aggregates of bubbles and liquid. In other words, a clearly defined, distinct interface between the liquid and gas in tanks 35 and 45 may not typically exist.

[0162] Furthermore, the pressures of the hydrogen and oxygen gases are transmitted through the continuous liquid columns of tubes 34 and 44 to both sides of the interelectrode membrane / ionomer separator, referred to as "M" in Figure 1. These columns typically contain a two-phase mixture of gaseous and liquid electrolytes, which can have a wide range of rapidly fluctuating densities and compressibility. Thus, the pressures of the liquid electrolytes on both sides of the interelectrode separator membrane / ionomer ("M" in Figure 1) can experience large, transient pressure differences, which sequentially result in high gas crossover.

[0163] In recent years, electrosynthesis liquid gas systems have been developed that directly generate bulk gas-phase products within the cell. That is, unlike the cell in Figure 1, permanent liquid-gas-solid state boundaries can exist in such cells, for example, at the electrodes of such cells (just as such boundaries can exist at the electrodes of many electroenergy liquid gas cells). As previously mentioned herein, an example of such a system is described in the scientific publication "The prospects of developing a highly energy-efficient water electrolyser by eliminating or mitigating bubble effects," Swiegers et al., published February 10, 2021, Sustainable Energy and Fuels, 2021, Vol. 5, pp. 1280-1310 (DOI: 10.1039 / d0se01886d). Another example is described in the subsequent scientific publication, "A high-performance capillary-fed electrolysis cell pr13omises more cost-competitive renewable hydrogen," Hodges et al., published March 15, 2022, Nature Communications, 2022, Vol. 13, page 1304 (DOI: 10.1038 / s41467-022-28953-x).

[0164] Figure 2 (prior art) shows an exemplary schematic diagram of a cell stack for a capillary-fed alkaline electrolytic cell in which a permanent liquid-gas-solid state interface exists at each electrode. The operation of such a cell stack is further described in the following patent applications, International Patent Publication Nos. 2022056603, 2022056604, 2022056605, and 2022056606, which are incorporated herein by reference.

[0165] The electrolytic cell in Figure 2 includes a cell stack 100 (shown within the dashed box in Figure 2). The balance of plant 200 generally consists of all the process engineering equipment outside the dashed box in Figure 2.

[0166] The cell stack 100 in Figure 2 is shown in an exemplary schematic diagram that allows for a direct comparison with the cell stack 10 in Figure 1. The cell stack 100 in Figure 2 contains five cells, each having an anode electrode (101, 103, 105, 107, 109) that directly generates bulk oxygen (O2) gas, and a cathode electrode (102, 104, 106, 108, 100) that directly generates bulk hydrogen (H2) gas, pressed tightly against a porous capillary separator between the electrodes, designated "P" in Figure 2. The porous capillary separator membrane exhibits high-speed capillary action. The high-speed capillary action of the porous capillary separator "P" has the effect of drawing conductive liquid aqueous electrolyte from the liquid electrolyte reservoir 120 at the base of each cell. The drawn-up liquid wets each of the electrodes 101-110 with the liquid electrolyte. The gas is generated by electrodes 101-110 in bulk form, not as bubbles, and is therefore not mixed with the liquid in the two-phase mixture as shown in Figure 1. The gas flows from the cell along gas tubes 130 (oxygen, O2) and 140 (hydrogen, H2) in directions 131 and 141, respectively, and exits from positions 135 and 145, respectively.

[0167] Each electrode is electrically connected via a porous conductive gas diffusion layer structure (indicated as "G" in Figure 2) to either a bipolar plate separating the cells (indicated as "P" in Figure 2) or an end terminal plate (directly attached to the "+" or "-" electrical terminals at each end of the cell stack in Figure 2).

[0168] It should be noted that gas pipes 131 and 141 may be incorporated into the cell stack in the form of headers and / or manifolds within the cell stack. In that case, the portion physically located within the cell stack is considered part of the cell stack, while the portion physically outside the cell stack is considered part of the balance of plant.

[0169] The interelectrode membrane separator ("P") divides each cell into two half-cells: an anode half-cell (oxygen-producing half-cell) and a cathode half-cell (hydrogen-producing half-cell). The generated oxygen and hydrogen, each half of which is produced, are kept separate from each other by the interelectrode membrane separator ("P") and the liquid reservoir 120.

[0170] When 10V is applied to the external electrical terminals indicated as "+" and "-" at the ends of the cell stack in Figure 2, the same voltages as those shown in the lower schematic diagram of Figure 1 can be applied to each of the anodes and cathodes present in the cell stack 100. That is, the voltages at anode 1 (101), anode 2 (103), anode 3 (105), anode 4 (107), and anode 5 (109) may be the same as those shown for these anodes in the lower schematic diagram of Figure 1. Similarly, the voltages at cathode 1 (102), cathode 2 (104), cathode 3 (106), cathode 4 (108), and cathode 5 (110) may be the same as those shown for these cathodes in the lower schematic diagram of Figure 1.

[0171] In the example in Figure 2, replenishment water (to replenish the water consumed during operation) is supplied by an external water tank 150 and is delivered from where the water is pumped by the pump 151, along the liquid pipe 152 in direction 153, to a set of valves indicated by "V" at the top of the cell. These valves may be required to regulate the flow of water to the cell. A second set of valves "V" at the bottom of each cell may be required to regulate the flow of excess liquid from the cell (for example, if water or liquid electrolyte is circulating in each cell). Such water can exit the cell along the liquid pipe 154 in direction 155 and return to the external water tank 150.

[0172] It should be noted that the tubes through which the liquid electrolyte flows, i.e., tubes 152 (including the one in direction 153) and 154 (including the one in direction 155), may be partially physically incorporated into the cell stack in the form of headers and / or manifolds that are physically located within the cell stack. In this case, the portion that is physically located within the cell stack is considered here to be part of the cell stack, while the portion that is physically outside the cell stack is considered here to be part of the balance of plant.

[0173] The cell stack 100 in Figure 2 may also be configured to output the generated hydrogen and oxygen in bulk form at a high pressure, for example, 1 bar higher than atmospheric pressure. Similar to the conventional electrolytic cell in Figure 1, in order to generate such pressurized gas, the cell stack 100 in Figure 2 may need to be able to contain and maintain the required pressure within it. In both cases, the balance of plant 200 must also necessarily be able to contain and maintain the required pressure within it; that is, the tubing, tanks, pumps, valves, and other components of the balance of plant must be able to handle the required pressure.

[0174] Comparing Figure 1 and Figure 2, it will be clear that the liquid supply / circulation system in the electrolytic cell in Figure 2 is completely different from that in Figure 1. Since the gas is generated directly in bulk in the cells within the cell stack 100, there is no need to pump the bubble-filled liquid electrolyte to a hydrogen or oxygen gas separator, as required in the conventional system shown in Figure 1.

[0175] Therefore, the balance of plant required for cell stack 100 in Figure 2 is necessarily different from that required for cell stack 10 in Figure 1. In other words, the recent development of new electrosynthesis cells that directly generate bulk gaseous products within the cell creates a need for a new and / or improved balance of plant.

[0176] The preferred embodiments described below provide novel and / or improved configurations for balance-of-plant electrosynthesis cells or cell stacks where bulk gas is directly generated in the cell or cell stack itself, as shown in the example in Figure 2. However, it should be understood that the preferred embodiments described below are not limited to the types of cells or cell stacks shown in Figure 2 and the related description. The preferred embodiments described below may construct novel and / or improved configurations for balance-of-plant hosts of other electrosynthesis and electroenergy liquid gas cells or cell stacks not described herein.

[0177] Preferred Embodiment The inventors of this invention believe the following: (1) Gas management, for example i. Gas pressure management; ii. Gas pressure equalization; iii. Gas pressure control; and / or iv. Gas circulation or recirculation, including during "standby" periods; (2) Management of liquids; (3) Stack cooling management; (4) Monitoring and managing the status of cells; (5) Configuration and management of cell stacks; and / or (6) Load following and / or grid balancing In this regard, we have developed new and / or improved process engineering systems, apparatus, configurations and / or operating methods for the balance of plants of electrosynthesis or electroenergy liquid gas cells or cell stacks.

[0178] Each of the above embodiments will be described in more detail below. Each of the above embodiments may be implemented within an automated or PLC-controlled balance of plant, that is, each may be applied automatically, for example via a PLC, or operate passively in parallel with the automated management of the balance of plant.

[0179] Preferably, without exclusivity, the above embodiments relate to a balance of plant whose operation is automated by computer control by one or more programmable logic controllers (PLCs) that can utilize the sensors, valves, pumps, and other conventional components of the balance of plant to operate without active human intervention.

[0180] Any balance of plant incorporating one or more of these embodiments individually or in any combination is to be understood as being within the scope of this specification. Furthermore, it should be understood that many modifications, changes, substitutions, or alterations will be apparent to those skilled in the art without departing from the scope of this specification.

[0181] (1)(i) Gas management: Gas pressure management When investigating the operation of electrosynthetic or electroenergy liquid gas cells or cell stacks under pressure, the inventors recognized that such cells or cell stacks must be physically able to withstand the pressure difference between the inside and outside of the cell or cell stack. That is, cells and cell stacks typically require strong and thick outer walls, depending on the degree of the aforementioned pressure difference. However, assembling this type of cell into a cell stack that can handle and maintain the pressure difference is typically complex and demanding. In fact, while not always impossible, it can typically be extremely difficult, if not impossible, to assemble such cells into a cell stack with acceptable reliability using high-speed, high-volume industrial manufacturing processes.

[0182] The inventors recognize that this problem can be avoided by incorporating the cell or cell stack into a pressure vessel, where the annular volume between the outer wall of the cell or cell stack and the inner wall of the pressure vessel is filled with a liquid or gas, referred herein to as an annular liquid or annular gas, pressurized to a pressure similar to or slightly higher than the pressure inside the cell or cell stack. For example, in the case of annular liquids, since liquids and gases are generally easily compressed using a simple pump, the pressure of such annular liquid or annular gas can easily match, or be maintained close to or slightly higher than, the internal pressure of the cell. Such a configuration ensures that the pressure difference between the inside and outside of the cell or cell stack can always be small, thereby enabling the use of simpler cells with thinner walls that are more easily incorporated into cell stacks, including in high-speed, high-volume industrial manufacturing processes. Thus, such a configuration potentially enables high-speed, high-volume industrial manufacturing and assembly of cell stacks that can be used, for example, to generate or consume gases with high absolute pressures.

[0183] Figure 3 shows a system (i.e., process engineering configuration) 201 including a cell or cell stack 210 incorporated within a pressure vessel 220. The pressure vessel 220 surrounds the cell or cell stack 210. Liquid and gas pipes 230 and 240 from the cell or cell stack 210 penetrate the wall of the pressure vessel 220, allowing liquid and gas reactants and / or products to be delivered to / removed from the cell or cell stack 210, including under pressure. The annular volume between the cell or cell stack 210 and the wall of the pressure vessel 220 is occupied by an annular liquid 250 or annular gas 255. That is, the pressure vessel 220 contains the annular liquid 250 or annular gas 255. The annular liquid 250 or annular gas 255 can be passed into the pressure vessel 220 via an inlet port 251. From the inlet port 251, the annular liquid 250 or annular gas 255 flows around the cell or cell stack 210 and can fill the pressure vessel 220 until it reaches the outlet port 252, where the annular liquid 250 or annular gas 255 can exit the pressure vessel 220.

[0184] Preferably, the pressure difference between the gas and liquid inside the cell or cell stack 210 and the surrounding annular liquid 250 or annular gas 255 outside the cell or cell stack 210 is absolutely low and / or low relative to the absolute pressure of the gas and / or liquid inside the cell or cell stack 210. Preferably, the cell or cell stack 210 is sealed to exclude the annular liquid 250 or annular gas 255 so that it does not penetrate the cell or cell stack 210 and does not come into direct contact with the electrodes inside the cell or cell stack 210. Also, the gas and / or liquid inside the cell or cell stack 210 should not leak into the annular volume and mix with the annular liquid 250 or annular gas 255. Preferably, though not exclusive, the annular liquid 250 or annular gas 255 passes continuously, continuously, or periodically through the space between the cell or cell stack 210 and the wall of the pressure vessel 220. Optionally, the annular liquid 250 or annular gas 255 is cooled or heated before or during its passage through the space between the cell or cell stack 210 and the wall of the pressure vessel 220, thereby controlling the temperature of the cell or cell stack 210. Preferably, but not exclusively, the annular liquid 250 or annular gas 255 is not significantly conductive. Preferably, but not exclusively, the annular liquid 250 or annular gas 255 is not significantly corrosive.

[0185] In another exemplary embodiment, the annular liquid 250 in the pressure vessel 220 may be pressurized by a pump that pumps the liquid into the pressure vessel 220 via an inlet port 251. The pump may be controlled, preferably, by a programmable logic controller (PLC) in a balance of plant that controls or partially controls the system and monitors the pressure in the liquid 250 and inside the cell or cell stack 210 using pressure sensors. The PLC may, for example, turn the pump on and off to ensure that the liquid 250 in the pressure vessel 220 has a pressure close to the pressure of the gas and / or liquid inside the cell or cell stack 210.

[0186] In a non-limiting example, the annular liquid 250 is water, for example, deionized water. Preferably, but not exclusively, the annular liquid 250, which is water entering port 251, is at ambient temperature and is heated by the cell stack 210 in the pressure vessel 220. In this way, the incoming water (annular liquid 250) (through port 251) can act to cool the cell or cell stack 210. Then, as the heated annular liquid 250, i.e., heated water, exits the pressure vessel 220 through port 252, the heat removed from the cell or cell stack 210 is carried elsewhere so that it is released when the water cools to ambient temperature. Preferably, but not exclusively, the flow of the annular liquid 250 through the pressure vessel 220 is regulated to maintain the temperature of the cell or cell stack 210 at or near a target temperature. Preferably, but not exclusively, the cell or cell stack 210 has low cooling requirements, so this cooling mechanism is sufficient to maintain the operating temperature of the cell or cell stack 210 without requiring any other cooling mechanism.

[0187] Preferably, but not exclusively, if the cell or cell stack 210 is of an electro-synthetic liquid-gas process that consumes water, the annular liquid 250 passing through the pressure vessel 220 is makeup water that is later added separately to the system to replenish the water consumed during operation. Preferably, but not exclusively, if the cell or cell stack 210 is of an electro-energy liquid-gas process, the annular liquid 250 is water that is produced by the cell or cell stack 210 during operation and previously removed separately from the system.

[0188] In another exemplary embodiment, where the fluid surrounding the cells or cell stacks 210 within the pressure vessel 220 is an annular gas 255, the annular gas 255 is preferably, but not exclusively, an inert gas such as nitrogen or argon in a sufficiently pure and dry form. Preferably, but not exclusively, the annular gas 255 passes continuously, continuously, or periodically, and preferably slowly, through the annular space between the cells or cell stacks 210 and the inner wall of the pressure vessel 220. That is, the annular gas 255 passes through the space between the cells or cell stacks 210 and one or more walls of the pressure vessel 220. Preferably, but not exclusively, the annular gas 255 exiting the pressure vessel 220, for example, in a pipe 252, is continuously monitored to detect the presence of any contaminated gas that may have leaked from the cells or cell stacks 210 into the annular gas 255, thereby alerting the balance of plant safety system to the presence of a gas leak from the inside to the outside of the cells or cell stacks 210. That is, optionally, the annular gas 255 exits the pressure vessel 220, and the exiting annular gas is monitored to detect the presence of one or more contaminating gases. Preferably, but not exclusively, if the product of an electrochemical reaction is a gas output through either tube 230 or 240, the product gas is monitored by the balance of plant for contamination by the inert annular gas 255 described above, thereby alerting the safety system of gas leaks from the outside to the inside of the cell or cell stack. Preferably, but not exclusively, a condensate trap or similar liquid capture device is attached to the bottom of the pressure vessel 220 or to the outlet 252 of the annular gas 255 from the pressure vessel, thereby detecting and capturing any liquid that may have leaked from the cell or cell stack 220 into the annular gas 255. In this way, the safety system may alert to the presence of liquid leaks from the inside to the annular gas 255 of the cell or cell stack 210. Furthermore, such leaks may be contained and contained within the condensate trap or liquid capture device. Optionally, cyclic gas 255 is a reaction gas or product gas in an electrochemical reaction.

[0189] Preferably, the cell or cell stack 210 can withstand an internal-external pressure difference across its walls of less than 0.1 bar, less than 0.15 bar, less than 0.2 bar, less than 0.3 bar, less than 0.4 bar, less than 0.5 bar, less than 0.75 bar, less than 1 bar, less than 1.5 bar, less than 2 bar, less than 3 bar, less than 4 bar, less than 5 bar, less than 7.5 bar, or less than 10 bar.

[0190] Preferably, the pressure difference between the pressure of the operating annular liquid 250 or annular gas 255 and the pressure of the gas and / or liquid in the cell or cell stack 210 is less than 0.001 bar, less than 0.002 bar, less than 0.003 bar, less than 0.005 bar, less than 0.010 bar, less than 0.020 bar, less than 0.040 bar, less than 0.050 bar, less than 0.075 bar, less than 0.100 bar, less than 0.125 bar, less than 0.150 bar, less than 0.200 bar, less than 0.300 bar, less than 0.400 bar, less than 0.500 bar, less than 0.750 bar, less than 1 bar, less than 2 bar, less than 5 bar, less than 10 bar, or less than 20 bar.

[0191] The inventors have further recognized that, in the above configuration, gaseous bodies may become trapped in the pressure vessel 220 when the annular liquid 250 is first filled or during operation, for example, due to gas leakage from the cell or cell stack 210. To remove such gases, an arrangement within the pressure vessel, such as in the form of an expansion tank containing a liquid-gas interface, may be required.

[0192] Figure 4 schematically shows a system (i.e., a process engineering configuration) 300 in which a cell or cell stack 210 configured inside a pressure vessel 220 is surrounded by an annular liquid 250. The pressure vessel 220 surrounds the cell or cell stack 210. The annular liquid 250 can flow into the pressure vessel 220 through an inlet port 251 and out of the pressure vessel 220 through an outlet port 252. Liquid and gas pipes 230 and 240 from the cell or cell stack 210 penetrate the wall of the pressure vessel 220, allowing liquid and gaseous reactants and / or products to be delivered to / removed from the cell stack, including under pressure.

[0193] This configuration includes an expanded volume section / container 310 containing the body of the annular liquid 250, which is fluidly connected to the annular liquid 250 in the pressure vessel 220. The annular liquid 250 in the expanded volume section / container 310 has a level 320, above which there is headspace occupied by the gas 330. Preferably, but not exclusively, the expanded volume section / container 310 is positioned at a point on the pressure vessel 220 where any gas in the annular liquid 250 in the pressure vessel 220 accumulates. Preferably, but not exclusively, the expanded volume section / container 310 also provides a change in the volume of the annular liquid 250 in the pressure vessel 220 around the cell stack 210, for example, during temperature changes.

[0194] In a further exemplary embodiment, the annular liquid 250 in the pressure vessel 220 may be pressurized by a gas 330 in an attached expansion volume / container 310. Optionally, the gas 330 may be a gas generated by or used by a cell or cell stack 210. In doing so, the annular liquid 250 is pressurized to and / or has a pressure comparable to the pressure of the gas and / or liquid in the cell stack 210 (provided that if there are two or more gases in the cell stack, they are maintained at approximately equal pressures).

[0195] (1)(ii)(a) Gas management: Gas pressure equalization - Embodiment 1 In pressurized electrosynthesis or electroenergy liquid gas cells containing two gas-phase reactants and / or products, each existing in bulk form within its own separate volumetric sections within a cell or cell stack, techniques have been devised to equalize (balance) their pressures and maintain them equal during operation. Process engineering configurations and methods have been developed for improved or substantial equalization of gas pressures, including high absolute pressures for each gas.

[0196] Figures 5 and 6 illustrate embodiments of such a gas pressure equalization system 400. Figure 5 shows a first modification of system 400a in which a single pressure equalization tank is used, while Figure 6 shows a second modification 400b in which multiple pressure equalization tanks are used.

[0197] single pressure equalization tank In Figure 5, the electrosynthesis or electroenergy liquid gas cell or cell stack 210 is optionally incorporated into or enclosed within a pressure vessel 220, and optionally contains an annular liquid 250 or annular gas 255 between the outer wall of the cell or cell stack 210 and the inner wall of the pressure vessel 220 (not shown in Figure 5), as described in Figures 3-4 and related descriptions. The cell or cell stack 210 generates or consumes a first gas (gas 1) in bulk form within the cell or cell stack. The cell or cell stack 210 is configured to keep the first gas (gas 1) in bulk form separate within the cell or cell stack 210. Preferably, though not necessarily, the cell or cell stack 210 can generate or consume two different gases in bulk form, namely a first gas (gas 1) and a second gas (gas 2), within the cell or cell stack. In this particular example, the cell or cell stack 210 is configured such that the bulk form of the first gas (gas 1) remains separated from the bulk form of the second gas (gas 2) within the cell or cell stack 210. Each gas occupies its own distinct and separate volume within the cell or cell stack 210. The first gas (gas 1) enters or leaves the cell or cell stack 210 via a first gas conduit 430 connected to a first pressure equalization tank 410, which contains, or at least partially contains, a first liquid 470 that partially fills the first pressure equalization tank 410. The first headspace 450 of the first pressure equalization tank 410 is filled with the first gas (gas 1). The first pressure equalizing tank 410 further has an outlet / inlet gas port 431 (or gas pipe or gas conduit) for the first gas (gas 1), and along therefor preferably, not exclusively, a first valve (V) controls the pressure of the first gas (gas 1) within the first pressure equalizing tank 410 and within the operating cell or cell stack 210. A A valve (V) 480 (for example, a back pressure valve or back pressure regulator) is positioned. The first gas (gas 1) enters or leaves the first pressure equalization tank 410 via the first external gas conduit 432 (i.e., the first external gas pipe 432) which is connected to the first pressure equalization tank 410. Optionally, the first external gas conduit 432 has a valve (V) A ) Connected to one side of 480, the outlet / inlet gas port 431 is the first valve (VA It is connected to the other side of 480.

[0198] Accordingly, a gas equalization system 400a for an electrosynthetic or electroenergy liquid gas cell or cell stack 210 is provided, wherein the cell or cell stack 210 is configured to separate and retain a bulk form of a first gas (gas 1) within the cell or cell stack 210. In another example, preferably, the cell or cell stack 210 is configured to keep the bulk form of the first gas (gas 1) separate from the bulk form of a second gas (gas 2) within the cell or cell stack 210. The gas equalization system 400a comprises a first equalization tank 410 for at least partially containing a first liquid 470 having a first liquid level 471 and for partially containing a bulk form of the first gas (gas 1). The first gas (gas 1) is positioned above the first liquid level 471. A first gas conduit 430 is provided for transferring the bulk form of the first gas (gas 1) between the cell or cell stack 210 and the first equalization tank 410.

[0199] Preferably, the first pressure equalization tank 410 is positioned below, below, or below the cell or cell stack 210 relative to gravity, preferably completely below, below, or below. Preferably, the first gas conduit 430 is positioned above the first liquid level 471. Preferably, the first gas conduit 430 is positioned at or near the top (i.e., top surface) of the first pressure equalization tank 410. In another example, the first gas is partially held in the first headspace 450 above the first liquid level 471 of the first liquid 470 in the first pressure equalization tank 410. In another example, the first gas conduit 430 is positioned above the first liquid level 471. In another example, the first gas conduit 430 is positioned in the first headspace 450. In another example, the first gas conduit 430 is positioned at the top of the first pressure equalization tank 410. In another example, a first outlet / inlet gas port 431, provided for the transfer of a first gas from or into a first pressure equalization tank 410, is located above the first liquid level 471. In one example, the first pressure equalization tank 410 is partially filled with a first liquid 470. Preferably, the first gas (gas 1) is sparingly soluble in the first liquid 470.

[0200] The second gas (gas 2) also exists in bulk form within the cell or cell stack 210 and enters or leaves the cell or cell stack 210 via the second gas port 440 (or gas pipe or gas conduit), along which preferably, non-exclusively, a second valve (V) controls the pressure of the second gas (gas 2) in the cell or cell stack 210 during operation. B )490 (for example, a back pressure valve or regulator) is fixed in place.

[0201] The gas pressure equalization system 400a operates as follows: The pressures of the first gas (gas 1) and the second gas (gas 2) in the cell or cell stack are controlled by the back pressure valve V A and V B They are managed individually. Such management may be performed manually or automatically, for example, by a control PLC. Valve V A and V B These valves are repeatedly and systematically opened or closed relative to each other, thereby balancing the pressures of gas 1 and gas 2, respectively. That is, valve V A and V B By repeatedly and systematically opening and closing these gates relative to each other, the pressures of the first gas (gas 1) and the second gas (gas 2) can be equalized or substantially equalized during the operation of the electrosynthesis or electrical energy cell or cell stack.

[0202] Accordingly, a method is provided for operating a gas equalization system 400a for an electrosynthesis or electroenergy liquid gas cell or cell stack 210. The method comprises operating the cell or cell stack 210 to produce or consume a first gas (gas 1), wherein the cell or cell stack 210 is configured to keep the first gas (gas 1) in bulk form separate within the cell or cell stack 210. In another example, the method comprises operating the cell or cell stack 210 to produce or consume a first gas (gas 1) and then a second gas (gas 2), wherein the cell or cell stack 210 is configured to keep the first gas (gas 1) in bulk form separate from the second gas (gas 2) in bulk within the cell or cell stack 210. The method also includes a first gas (gas 1) flowing in or out of a first equalization tank 410 in bulk form via a first gas conduit 430. The first pressure equalization tank 410 contains at least partially a first liquid 470 having a first liquid level 471 and a first gas (gas 1) positioned above the first liquid level 471. In one example, the first liquid 470 has a substantially constant density during operation. In another example, the first liquid 470 does not contain or substantially contains bubbles during operation. Preferably, the first liquid 470 does not enter the cell or cell stack 210 during operation. Optionally, the first liquid 470 is the same as the liquid electrolyte of the electrochemical reaction occurring in the cell or cell stack 210. Optionally, the pressure of the first liquid 470 in the first pressure equalization tank 410 is substantially equalized with the pressure of the liquid electrolyte in the cell or cell stack 210. Optionally, this method includes adjusting the pressure of the first gas (gas 1) in the first pressure equalization tank 410 to maintain the first liquid level 471 at a certain height.

[0203] The inventors have surprisingly found that the headspace 450 of the first pressure equalization tank 410 functions as, or can be provided with, a buffer volume that significantly facilitates the equalization or substantial equalization of the pressures of the first gas (gas 1) and the second gas (gas 2) in the cell or cell stack during operation. Furthermore, the presence of the headspace 450 in the first pressure equalization tank 410 also makes it possible to achieve such equalization or substantial equalization, i.e., more ready, more reliable, more stable (over time), and / or more quickly.

[0204] Furthermore, if the first liquid 470 in the first pressure equalization tank 410 also contains a liquid electrolyte that is circulated and used within the cell or cell stack 210, then after their equalization or substantial equalization, the liquid electrolyte will have the same or substantially the same pressure as the first gas (gas 1) and the second gas (gas 2).

[0205] Therefore, the above method provides a means for equalizing or substantially equalizing the pressures of all individual and separate bulk gases (gas 1 and gas 2), as well as equalizing the pressure of the liquid electrolyte (470) in the cell or cell stack 210.

[0206] Furthermore, pressure is directly transmitted to the inter-electrode separator membrane / ionomer by gases, namely the first gas (gas 1) and the second gas (gas 2), and not through a column of two-phase mixtures of liquid electrolyte and gas, as seen in conventional electrolytic cells (see Figure 1 and related text). This avoids high gas crossover due to fluctuations and transient pressure differences across the separator.

[0207] Multi-pressure equalization tank Figure 6 shows a variation of the above embodiment using two or more pressure equalization tanks, for example, a separate pressure equalization tank can be used for each bulk gas present in a cell or cell stack.

[0208] In Figure 6, the electrosynthesis or electroenergy liquid gas cell or cell stack 210 is optionally incorporated into or enclosed within a pressure vessel 220, and optionally contains an annular liquid 250 or annular gas 255 between the outer wall of the cell or cell stack 210 and the inner wall of the pressure vessel 220 (not shown in Figure 6), as described in Figures 3-4 and related descriptions. The cell or cell stack 210 produces or consumes two different gases in bulk form, namely gas 1 (i.e., first gas) and gas 2 (i.e., second gas). Each gas occupies its own separate and distinct volume within the cell or cell stack 210. Gas 1 (in bulk form) exits from or enters the cell or cell stack 210 via a first gas conduit 430 connected to a first pressure equalization tank 410 for gas 1 (i.e., first gas). Gas 2 (in bulk form) enters or leaves the cell or cell stack 210 via a second gas conduit 440 connected to a second pressure equalization tank 420 for gas 2 (i.e., the second gas). The first pressure equalization tank 410 contains, or at least partially contains, a first liquid 470 that partially fills the first pressure equalization tank 410, and the second pressure equalization tank 420 contains, or at least partially contains, a second liquid 473 that partially fills the second pressure equalization tank 420. Optionally, the first liquid 470 in the first pressure equalization tank 410 may be a different liquid from the second liquid 473, or the first liquid 470 may be the same liquid as the second liquid 473. Preferably, though not necessarily, the first liquid 470 in the first pressure equalization tank 410 is the same liquid as the second liquid 473 in the second pressure equalization tank 420. Optionally, the first liquid 470 in the first pressure equalization tank 410 is a different liquid from the second liquid 473 in the second pressure equalization tank 420. Therefore, the first pressure equalization tank 410 contains at least partially a first liquid 470 having a first liquid level 471 and partially a first gas (gas 1) in bulk form. Therefore, the second pressure equalization tank 420 contains at least partially a second liquid 473 having a second liquid level 472 and partially a second gas (gas 2) in bulk form.

[0209] Preferably, gas 1 (i.e., first gas) entering and leaving the first pressure equalization tank 410 flows through a first headspace 450 above the first liquid level 471 of the first liquid 470 in the first pressure equalization tank 410. Preferably, gas 2 (i.e., second gas) entering and leaving the second pressure equalization tank 420 flows through a second headspace 460 above the second liquid level 472 of the second liquid 473 in the second pressure equalization tank 420. The first liquid level 471 and the second liquid level 472 in each pressure equalization tank 410 and 420 are preferably transparent and clearly defined (for example, if no bubbles are present in the first liquid 470 or the second liquid 473). The first pressure equalization tank 410 has a first outlet / inlet gas port 431 (or gas pipe or gas conduit) for gas 1, which optionally includes a first valve (V) that controls the pressure of gas 1 in the first pressure equalization tank 410, gas conduit 430, and cell or cell stack 210 during operation. A A valve 480 is installed. Gas 1 leaves or enters the first pressure equalization tank 410 (i.e., first gas) via a first external gas conduit 432 (i.e., first external gas pipe 432) which is connected to the first pressure equalization tank 410 for gas 1 (i.e., first gas). Optionally, the first external gas conduit 432 is connected to a first valve (V A ) Connected to one side of 480, the first outlet / inlet gas port 431 is connected to the first valve (V A The second pressure equalizing tank 420 is connected to the other side of 480. The second pressure equalizing tank 420 has a second outlet / inlet gas port 441 (or gas pipe or gas conduit) for gas 2, which optionally has a second valve (V) that controls the pressure of gas 2 in the second pressure equalizing tank 420, gas conduit 440, and cell stack 210 during operation. B A valve 490 is installed. Gas 2 exits from or enters the second pressure equalization tank 420 via a second external gas conduit 442 (i.e., second external gas pipe 442) which is connected to the second pressure equalization tank 420 for gas 2 (i.e., second gas). Optionally, the second external gas conduit 442 is connected to a second valve (V B )490 is connected to one side, and the second outlet / inlet gas port 441 is connected to the second valve (V B It is connected to the other side of )490. First valve (V A)480 and / or second valve (V B In cases where )490 is not used, the first external gas conduit 432 and the first outlet / inlet gas port 431 may be a single continuous gas conduit, pipe or line (i.e., the first external gas pipe), and / or the second external gas conduit 442 and the second outlet / inlet gas port 441 may be a single continuous gas conduit, pipe or line (i.e., the second external gas pipe).

[0210] Preferably, the first gas conduit 430 is located above the first liquid level 471. Preferably, the first gas conduit 430 is located at or near the top (i.e., top surface) of the first pressure equalization tank 410. Preferably, the second gas conduit 440 is located above the second liquid level 472. Preferably, the second gas conduit 440 is located at or near the top (i.e., top surface) of the second pressure equalization tank 420. Preferably, the first pressure equalization tank 410 and the second pressure equalization tank 420 are located below, below, or below the cell or cell stack 210 relative to gravity, preferably completely below, below, or below. In another example, the first gas is partially held in the first headspace above the first liquid level 471 of the first liquid 470 in the first pressure equalization tank. In another example, the first gas conduit 430 is located above the first liquid level 471. In another example, the first gas conduit 430 is located in the first headspace 450. In another example, the first gas conduit 430 is located at the top of the first pressure equalization tank 410. In another example, the first outlet / inlet gas port 431, provided for the transfer of the first gas from or into the first pressure equalization tank 410, is located above the first liquid level 471. In another example, the second gas is partially held in the second headspace 460 above the second liquid level 472 of the second liquid 473 in the second pressure equalization tank 420. In another example, the second gas conduit 440 is located above the second liquid level 472. In another example, the second gas conduit 440 is located in the second headspace 460. In another example, the second gas conduit 440 is located at the top of the second pressure equalization tank 420. In another example, the second outlet / inlet gas port 441, provided for the transfer of the second gas from or into the second pressure equalization tank 420, is located above the second liquid level 472. Preferably, the first gas (gas 1) is sparingly soluble in the first liquid 470, and / or the second gas (gas 2) is sparingly soluble in the second liquid 473.

[0211] The gas pressure equalization system 400b in Figure 6 operates as follows: The pressures of the first gas (gas 1) and the second gas (gas 2) in the cell or cell stack are controlled by the back pressure valve V A and V BThey are managed individually. Such management may be performed manually or automatically, for example, by a control PLC. Valve V A and V B These valves are repeatedly and systematically opened or closed relative to each other, thereby balancing the pressures of gas 1 and gas 2, respectively. That is, valve V A and V B By repeatedly and systematically opening and closing these gates relative to each other, the pressures of the first gas (gas 1) and the second gas (gas 2) can be equalized or substantially equalized during the operation of the electrosynthesis or electrical energy cell or cell stack.

[0212] Accordingly, a method is provided for operating a gas equalization system 400b for an electrosynthesis or electroenergy liquid gas cell or cell stack 210. The method comprises operating the cell or cell stack 210 to produce or consume a first gas (gas 1) and a second gas (gas 2), wherein the cell or cell stack 210 is configured such that the first gas (gas 1) in bulk form remains separated from the second gas (gas 2) in bulk form within the cell or cell stack 210. The method also includes the first gas (gas 1) flowing in or out of a first equalization tank 410 in bulk form via a first gas conduit 430. The first equalization tank 410 at least partially contains a first liquid 470 having a first liquid level 471 and the first gas (gas 1) positioned above the first liquid level 471. Furthermore, the method includes a second gas (gas 2) flowing in bulk into or out of a second pressure equalization tank 420 via a second gas conduit 440, the second pressure equalization tank 420 at least partially containing a second liquid 473 having a second liquid level 472, and the second gas (gas 2) being positioned above the second liquid level 472. In one example, the first liquid 470 and the second liquid 473 (if they are different liquids) have a substantially constant density during operation. In another example, the first liquid 470 and the second liquid 473 do not contain or substantially contain bubbles during operation. Preferably, the first liquid 470 and the second liquid 473 do not enter the cell or cell stack 210 during operation. Optionally, the first liquid 470 and / or the second liquid 473 are the same as the liquid electrolytes for the electrochemical reactions occurring within the cell or cell stack 210. Optionally, the pressure of the first liquid 470 in the first equalizing tank 410 and / or the pressure of the second liquid 473 in the second equalizing tank 420 are substantially equalized with the pressure of the liquid electrolyte in the cell or cell stack 210. Optionally, the method includes adjusting the pressure of the first gas (gas 1) in the first equalizing tank 410 to maintain the first liquid level 471 at a first height, and / or adjusting the pressure of the second gas (gas 2) in the second equalizing tank 420 to maintain the second liquid level 472 at a second height. Preferably, but not necessarily, the first height is equal to or substantially equal to the second height, or the first liquid level 471 is equal to or substantially equal to the second liquid level 472.Optionally, the first height may be different from the second height, or the first liquid level 471 may be different from the second liquid level 472.

[0213] The inventors have surprisingly found that the headspace 450 of the first equalizing tank 410 and the headspace 460 of the second equalizing tank 420 function as, or can be provided with, buffer volumes that significantly facilitate the equalization or substantial equalization of the pressures of the first gas (gas 1) and the second gas (gas 2) in the cell or cell stack during operation. Furthermore, the presence of the headspace 450 in the first equalizing tank 410 and the headspace 460 in the second equalizing tank 420 may enable such equalization or substantial equalization to be achieved more readily, more reliably, more stable (over time), and / or more quickly.

[0214] Furthermore, if the first liquid 470 in the first pressure equalization tank 410 and the second liquid 473 in the second pressure equalization tank 420 also contain liquid electrolytes that are circulated and used within the cell or cell stack 210, then these liquid electrolytes will have the same or substantially the same pressure as the first gas (gas 1) and the second gas (gas 2) after their equalization or substantial equalization.

[0215] Therefore, the above method provides a means for equalizing or substantially equalizing the pressures of all individual and separate bulk gases (gas 1 and gas 2), as well as equalizing the pressure of the liquid electrolyte in the cell or cell stack 210.

[0216] Furthermore, pressure is directly transmitted to the inter-electrode separator membrane / ionomer by gases, namely the first gas (gas 1) and the second gas (gas 2), and not through a column of two-phase mixtures of liquid electrolyte and gas, as seen in conventional electrolytic cells (see Figure 1 and related text). This avoids high gas crossover due to fluctuations and transient pressure differences across the separator.

[0217] However, it should be understood that different liquids 470 and 473 may be used in the first and second pressure equalization tanks 410 and 420, and that one or both of these liquids 470 and 473 may not be the same as the liquid electrolyte used in the cell or cell stack.

[0218] (1)(ii)(b) Gas management: Gas pressure equalization - Embodiment 2 Figure 7 shows a further embodiment of the gas pressure equalization system 401.

[0219] The electrosynthetic or electroenergy liquid gas cell or cell stack 210 is optionally incorporated into or enclosed within a pressure vessel 220, and optionally contains an annular liquid 250 or annular gas 255 between the outer wall of the cell or cell stack 210 and the inner wall of the pressure vessel 220 (not shown in Figure 7), as described in Figures 3-4 and related descriptions. The cell or cell stack 210 produces or consumes two different gases in bulk form, namely gas 1 (i.e., first gas) and gas 2 (i.e., second gas). Each gas occupies its own separate and distinct volume within the cell or cell stack 210. Gas 1 (in bulk form) exits from or enters the cell or cell stack 210 via a first gas conduit 430 connected to a first pressure equalization tank 410 for gas 1 (i.e., first gas). Gas 2 (in bulk form) enters or leaves the cell or cell stack 210 via a second gas conduit 440 connected to a second pressure equalization tank 420 for gas 2 (i.e., the second gas). The first pressure equalization tank 410 contains, or at least partially contains, a first liquid 470 that partially fills the first pressure equalization tank 410, and the second pressure equalization tank 420 contains, or at least partially contains, a second liquid 473 that partially fills the second pressure equalization tank 420. In this example, the first liquid 470 is preferably the same as the second liquid 473 (but not necessarily). The first pressure equalization tank 410 and the second pressure equalization tank 420 are in fluid communication with each other via a “connecting pipe” 415, which is similarly filled with the first liquid 470 / second liquid 473 (i.e., the same liquid in the preferred example). The connecting pipe 415 enables the transfer of the first liquid 470 or the second liquid 473 flowing between the first pressure equalization tank 410 and the second pressure equalization tank 420 via the connecting pipe 415.

[0220] Preferably, the connecting pipe 415 is a connecting pipe with a relatively large diameter. Preferably, during operation, the connecting pipe is completely filled with the first liquid 470 / second liquid 473. This ensures that the connecting pipe 415 is not transferred to a different pressure equalization tank with either the first or second gas. Thus, the headspace 450 of the first pressure equalization tank 410 is filled with only the first gas (gas 1), while the headspace 460 of the second pressure equalization tank 420 is filled with only the second gas (gas 2). The end of the connecting pipe 415 is located at or near the bottom of each pressure equalization tank. That is, the connecting pipe 415 for transferring the first liquid 470 / second liquid 473 is located at or near the bottom (i.e., bottom surface) of the first pressure equalization tank 410, and at or near the bottom (i.e., bottom surface) of the second pressure equalization tank 420. The first liquid 470 from the first pressure equalization tank 410 can easily pass through the connecting pipe 415 to the second pressure equalization tank 420, and vice versa. Preferably, the connecting pipe 415 is configured to be filled with the first liquid 470 / second liquid 473 during operation. The liquids, or different liquids in some examples, the first liquid 470 in the first pressure equalization tank 410, the second liquid 473 in the second pressure equalization tank 420, and the first liquid 470 / second liquid 473 (which may be the same liquid) in the connecting pipe 415, have an invariant density, the liquids are essentially incompressible under operating conditions, and the liquids do not contain bubbles that could induce changes in the density and compressibility of the liquids, for example. This property results in improved gas equalization characteristics (as described later).

[0221] Preferably, but not exclusively, the first pressure equalizing tank 410 and the second pressure equalizing tank 420 are positioned or located at a level lower (i.e., below or below) than the level (i.e., in height or position) of the cell or cell stack 210 relative to gravity; that is, the first pressure equalizing tank 410 and the second pressure equalizing tank 420 are “infrastructure” tanks located below (i.e., below or below) the level of the cell or cell stack 210. Preferably, the first pressure equalizing tank 410 and the second pressure equalizing tank 420 are positioned completely below, below or below the cell or cell stack 210 relative to gravity. For example, the first pressure equalizing tank 410 is the first pressure equalizing infrastructure tank, and the second pressure equalizing tank 420 is the second pressure equalizing infrastructure tank. Preferably, but not exclusively, the first pressure equalizing tank 410 is positioned completely below the cell or cell stack 210 relative to gravity. Preferably, but not exclusively, the second pressure equalizing tank 420 is positioned completely below the cell or cell stack 210 relative to gravity. Preferably, the first gas conduit 430 is located above the first liquid level 471. Preferably, the first gas conduit 430 is located at or near the top (i.e., the upper surface) of the first pressure equalization tank 410. Preferably, the second gas conduit 440 is located above the second liquid level 472. Preferably, the second gas conduit 440 is located at or near the top (i.e., the upper surface) of the second pressure equalization tank 420.

[0222] Preferably, gas 1 (i.e., first gas) entering and leaving the first pressure equalization tank 410 flows through a first headspace 450 above the first liquid level 471 of the first liquid 470 in the first pressure equalization tank 410. Preferably, gas 2 (i.e., second gas) entering and leaving the second pressure equalization tank 420 flows through a second headspace 460 above the second liquid level 472 of the second liquid 473 in the second pressure equalization tank 420. The first liquid level 471 and the second liquid level 472 in each pressure equalization tank 410 and 420 are preferably transparent and clearly defined (if no bubbles are present in the first liquid 470 or second liquid 473). The first pressure equalization tank 410 has a first outlet / inlet gas port 431 (or gas pipe or gas conduit) for gas 1, which optionally includes a first valve (V) that controls the pressure of gas 1 in the first pressure equalization tank 410, gas conduit 430, and cell or cell stack 210 during operation. A A valve 480 is installed. Gas 1 leaves or enters the first pressure equalization tank 410 (i.e., first gas) via a first external gas conduit 432 (i.e., first external gas pipe 432) which is connected to the first pressure equalization tank 410 for gas 1 (i.e., first gas). Optionally, the first external gas conduit 432 is connected to a first valve (V A ) Connected to one side of 480, the first outlet / inlet gas port 431 is connected to the first valve (V A The second pressure equalizing tank 420 is connected to the other side of 480. The second pressure equalizing tank 420 has a second outlet / inlet gas port 441 (or gas pipe or gas conduit) for gas 2, which optionally has a second valve (V) that controls the pressure of gas 2 in the second pressure equalizing tank 420, gas conduit 440, and cell stack 210 during operation. B A valve 490 is installed. Gas 2 exits from or enters the second pressure equalization tank 420 via a second external gas conduit 442 (i.e., second external gas pipe 442) which is connected to the second pressure equalization tank 420 for gas 2 (i.e., second gas). Optionally, the second external gas conduit 442 is connected to a second valve (V B )490 is connected to one side, and the second outlet / inlet gas port 441 is connected to the second valve (V B It is connected to the other side of )490. First valve (V A )480 and / or second valve (VB In cases where )490 is not used, the first external gas conduit 432 and the first outlet / inlet gas port 431 may be a single continuous gas conduit, pipe or line (i.e., the first external gas pipe), and / or the second external gas conduit 442 and the second outlet / inlet gas port 441 may be a single continuous gas conduit, pipe or line (i.e., the second external gas pipe).

[0223] Accordingly, this embodiment provides a gas equalization system 401 for an electrosynthesis or electroenergy liquid gas cell or cell stack 210. The gas equalization system 401 comprises a first equalization tank 410 for partially containing a first liquid 470 having a first liquid level 471 and for partially containing a first gas. The first gas is located in a headspace 450 above the first liquid level 471. A first gas conduit 430 is provided for transferring the first gas in bulk form between the cell or cell stack 210 and the first equalization tank 410. A second equalization tank 420 is provided for partially containing a second gas, for at least partially containing a second liquid 473 having a second liquid level 472 (which, in this example, is preferably the same as the first liquid 470, though not necessarily), and for partially containing a second gas, the second gas is located in a headspace 460 above the second liquid level 472. A second gas conduit 440 is provided for transferring the second gas in bulk form between the cell or cell stack 210 and the second equalization tank 420. A connecting pipe 415 is provided to transfer the first liquid 470 / second liquid 473 between the first pressure equalization tank 410 and the second pressure equalization tank 420. The first pressure equalization tank 410 and the second pressure equalization tank 420 are located below the cell or cell stack 210. Thus, the first pressure equalization tank 410 contains at least partially the first liquid 470 having a first liquid level 471 and partially contains the first gas (gas 1) in bulk form. Thus, the second pressure equalization tank 420 contains at least partially the second liquid 473 having a second liquid level 472 and partially contains the second gas (gas 2) in bulk form. Preferably, though not necessarily, the first liquid 470 in the first pressure equalization tank 410 is the same liquid as the second liquid 473 in the second pressure equalization tank 420.

[0224] Preferably, the connecting pipe 415 is located below the first liquid level 471 and the second liquid level 472, preferably entirely or completely below them. In one example, the connecting pipe 415 is located at or near the bottom of the first pressure equalization tank 410 and at or near the bottom of the second pressure equalization tank 420. In another example, the connecting pipe 415 is entirely filled with the first liquid 470 / second liquid 473 during operation. In yet another example, the first gas is partially held in the first headspace above the first liquid level 471 of the first liquid 470 in the first pressure equalization tank. In yet another example, the first gas conduit 430 is located above the first liquid level 471. In yet another example, the first gas conduit 430 is located in the first headspace 450. In yet another example, the first gas conduit 430 is located at the top of the first pressure equalization tank 410. In another example, a first outlet / inlet gas port 431, provided for the transfer of a first gas from or into the first pressure equalization tank 410, is located above the first liquid level 471. In yet another example, a second gas is partially held in a second headspace 460 above the second liquid level 472 of the second liquid 473 in the second pressure equalization tank 420. In yet another example, a second gas conduit 440 is located above the second liquid level 472. In yet another example, the second gas conduit 440 is located in the second headspace 460. In yet another example, the second gas conduit 440 is located at the top of the second pressure equalization tank 420. In yet another example, a second outlet / inlet gas port 441, provided for the transfer of a second gas from or into the second pressure equalization tank 420, is located above the second liquid level 472. In another example, the first pressure equalization tank 410 is partially filled with the first liquid 470, and the second pressure equalization tank 420 is partially filled with the second liquid 473, preferably the first liquid 470 is the same as the second liquid 473. In yet another example, if the pressure of the first gas (gas 1) in the first pressure equalization tank 410 is different from the pressure of the second gas (gas 2) in the second pressure equalization tank 420, the first liquid 470 or the second liquid 473 flows between the first pressure equalization tank 410 and the second pressure equalization tank 420 via the connecting pipe 415.

[0225] operation The gas pressure equalization system 401 in Figure 7 operates as follows: When the pressure of gas 1 (first gas) exceeds the pressure of gas 2 (second gas), gas 1 causes the first liquid 470 to flow out from the first pressure equalization tank 410 to the second pressure equalization tank 420 via the connecting pipe 415. In this way, the first liquid level 471 in the first pressure equalization tank 410 decreases, the volume of gas 1 increases, and the pressure of gas 1 decreases, while the second liquid level 472 in the second pressure equalization tank 420 rises, the volume of gas 2 decreases, and the pressure of gas 2 increases. The first liquid 470 flows between the first pressure equalization tank 410 and the second pressure equalization tank 420 until the pressures of gas 1 and gas 2 become equal, at which point the flow of liquid between the first pressure equalization tank 410 and the second pressure equalization tank 420 stops.

[0226] Similarly, if the pressure of gas 2 (second gas) exceeds the pressure of gas 1 (first gas), gas 2 causes the second liquid 473 to flow out of the second pressure equalizing tank 420 to the first pressure equalizing tank 410 via the connecting pipe 415. In doing so, the second liquid level 472 in the second pressure equalizing tank 420 decreases, the volume of gas 2 increases, and the pressure of gas 2 decreases, while the first liquid level 471 in the first pressure equalizing tank 410 rises, the volume of gas 1 decreases, and the pressure of gas 1 increases. The second liquid 473 flows between the second pressure equalizing tank 420 and the first pressure equalizing tank 410 until the pressures of gas 1 and gas 2 become equal, at which point the flow of liquid between the second pressure equalizing tank 420 and the first pressure equalizing tank 410 stops.

[0227] Placing or positioning both the first pressure equalization tank 410 and the second pressure equalization tank 420 below the height of the cell and / or cell stack 210, i.e., as "infrastructure" tanks, facilitates the operation of the system 401. Minimizing the number of turns of the first gas conduit 430 and the second gas conduit 440 also minimizes the pressure difference between (i) gas 1 and gas 2 in the first pressure equalization tank 410 and the second pressure equalization tank 420, and (ii) the bulk forms of gas 1 and gas 2 in the cell or cell stack 210, respectively.

[0228] Therefore, this configuration provides a passive but automatic means of equalizing the pressures of gas 1 and gas 2 at any given time. That is, the pressure difference between the pressures of gas 1 and gas 2 in the first headspace 450 and the second headspace 460 is spontaneously compensated by the flow of the first liquid 470 / second liquid 473 between the first equalizing tank 410 and the second equalizing tank 420 until the pressures of gas 1 and gas 2 are equal or substantially equal.

[0229] The absolute pressures of the first gas (gas 1) and the second gas (gas 2) in the cell or cell stack are controlled by the back pressure valve V A and V B Although it can be changed by adjusting, the passive pressure balancing provided by the above system then allows those pressures to spontaneously equalize. Back pressure valve V A and V B Such adjustments may be performed manually or automatically, for example, by a control PLC. Valve V A and V B These valves are opened and closed repeatedly and systematically relative to each other, thereby changing the pressure of gas 1 or gas 2, respectively. That is, valve V A and V B The pressures of the first gas (gas 1) and the second gas (gas 2) can be changed by repeatedly and systematically opening and closing them relative to each other, after which they are spontaneously equalized or substantially equalized by the passive equalization system described above. Such adjustments can be performed during the operation of electrosynthesis or an electrical energy cell or cell stack.

[0230] Preferably, the first liquid 470 and the second liquid 473 in the first equalizing tank 410 and the second equalizing tank 420 have a large surface area of ​​the liquid-gas interface at the first liquid level 471 and the second liquid level 472, respectively, relative to the volume of their respective gases in the cell or cell stack 210 and the rest of the balance of plant, thereby resulting in faster equalization of gas pressure. The larger the surface area of ​​the gas-liquid interface at the first liquid level 471 and the second liquid level 472 relative to the volume of each gas, the smaller the rise and fall of the first liquid level 471 and the second liquid level 472, respectively, required to equalize the pressures of gas 1 and gas 2 and speed up the equalization process. Preferably, the first liquid 470 and the second liquid 473 in the first equalizing tank 410 and the second equalizing tank 420 have a large volume relative to their corresponding gases in the cell or cell stack 210, the volume of gas 1 and gas 2, and the rest of the balance of plant, thereby resulting in even greater equalization of gas pressure differences. For example, the volume of the first liquid 470 in the first pressure equalization tank 410 is greater than the volume of the first gas in the cell or cell stack 210, as well as the first headspace 450 and the first gas conduit 430. Similarly, for example, the volume of the second liquid 473 in the second pressure equalization tank 420 is greater than the volume of the second gas in the cell or cell stack 210, as well as the second headspace 460 and the second gas conduit 440. The larger the volumes of the first liquid 470 and the second liquid 473 in the first pressure equalization tank 410 and the second pressure equalization tank 420 are relative to the volume of each gas, the smaller the rise and fall of the first liquid level 471 and the second liquid level 472, respectively, required to equalize the pressures of gas 1 and gas 2 and to speed up the equalization process.

[0231] Furthermore, if the first liquid 470 in the first pressure equalization tank 410 and the second liquid 473 in the second pressure equalization tank 420 each contain liquid electrolytes that are circulated and used within the cell or cell stack 210, then these liquid electrolytes will have the same or substantially the same pressure as the first gas (gas 1) and the second gas (gas 2) after their equalization or substantial equalization.

[0232] Therefore, the above method provides a means to equalize or substantially equalize all pressures of separate bulk gases (gas 1 and gas 2) and equalize the pressure of the liquid electrolyte in the cell or cell stack 210.

[0233] It should be noted that in System 401, pressure is directly transmitted to the inter-electrode separator membrane / ionomer by gas, namely the first and second gases, and not through a column of two-phase mixtures of liquid electrolyte and gas, as seen in conventional electrolytic cells (as described in Figure 1 and related text). This avoids high gas crossover due to fluctuations and transient pressure differences across the separator.

[0234] It should be further noted that system 401 in Figure 7 can be easily configured to be converted to system type 400a in Figure 5 or system type 400b in Figure 6 simply by including a flow valve in the connecting pipe 415. Closing the flow valve to stop the movement of liquid between tanks 410 and 420 converts the system to system type 400b in Figure 6. Furthermore, closing the flow valve and removing the second liquid 473 in tank 420 converts the system to system type 400a in Figure 5. Thus, a single engineering configuration can be used to enable all three of the above systems.

[0235] How it works Another example provides a method for operating a gas equalization system, which involves operating an electrosynthesis or electroenergy liquid gas cell or cell stack to produce or consume a first gas or a second gas. If the pressure of the first gas exceeds the pressure of the second gas, and the first and second gases are in bulk form, the first liquid is discharged from the first equalization tank and flowed into the second equalization tank via a connecting pipe, thereby lowering the first liquid level in the first equalization tank, thereby lowering the pressure of the first gas, raising the second liquid level in the second equalization tank, thereby raising the pressure of the second gas, and after the first liquid has stopped flowing, the first liquid is allowed to flow until the pressures of the first gas and the second gas are equal.

[0236] If the pressure of the second gas exceeds the pressure of the first gas, and both the first and second gases are in bulk form, the second liquid (which may be the same liquid as the first liquid) is discharged from the second pressure equalization tank and introduced into the first pressure equalization tank via a connecting pipe, thereby lowering the second liquid level in the second pressure equalization tank, thereby lowering the pressure of the second gas, raising the first liquid level in the first pressure equalization tank, thereby raising the pressure of the first gas, and after the liquid stops flowing, the second liquid is allowed to flow until the pressure of the second gas and the pressure of the first gas become equal. Preferably, the first liquid and / or the second liquid have a substantially constant density during operation. In another example, the first liquid and / or the second liquid do not contain bubbles during operation. In another example, the first liquid and / or the second liquid do not enter cells or cell stacks during operation.

[0237] In another exemplary embodiment, a method is provided for operating a gas equalization system 401 for an electrosynthesis or electroenergy liquid gas cell or cell stack 210. This method includes the step of operating the electrosynthesis or electroenergy liquid gas cell or cell stack 401 to produce or consume a first gas and a second gas. The first gas flows into or out of a first equalization tank 410 via a first gas conduit 430. The first equalization tank 410 at least partially contains a first liquid 470 having a first liquid level 471, and the first gas is positioned above the first liquid level 471. The second gas flows into or out of a second equalization tank 420 via a second gas conduit 440. The second equalization tank 420 at least partially contains a second liquid 473 having a second liquid level 472, and the second gas is positioned above the second liquid level 472. The first liquid 470 and the second liquid 473 may be the same liquid, and they flow between the first pressure equalization tank 410 and the second pressure equalization tank 420 via the connecting pipe 415 when the pressure of the first gas in the first pressure equalization tank 410 differs from the pressure of the second gas in the second pressure equalization tank 420. Preferably, the connecting pipe 415 is positioned below the first liquid level 471 and the second liquid level 472 during operation.

[0238] If the pressure of the first gas in the first pressure equalization tank exceeds the pressure of the second gas in the second pressure equalization tank, the first liquid will flow out of the first pressure equalization tank and into the second pressure equalization tank via the connecting pipe. This will cause the liquid level in the first pressure equalization tank to drop, thereby lowering the pressure of the first gas, and the liquid level in the second pressure equalization tank to rise, thereby increasing the pressure of the second gas. The first liquid will continue to flow until the pressures of the first and second gases become equal.

[0239] If the pressure of the second gas in the second pressure equalization tank exceeds the pressure of the first gas in the first pressure equalization tank, the second liquid will flow out of the second pressure equalization tank and into the first pressure equalization tank via the connecting pipe. This will cause the liquid level in the second pressure equalization tank to drop, thereby lowering the pressure of the second gas, and the liquid level in the first pressure equalization tank to rise, thereby increasing the pressure of the first gas. The second liquid will continue to flow until the pressure of the second gas and the pressure of the first gas become equal.

[0240] In one example, the first liquid and / or the second liquid flow spontaneously in response to any pressure difference between the pressure of the first gas in the first pressure equalizing tank and the pressure of the second gas in the second pressure equalizing tank. Another example involves adjusting the pressure of the first gas in the first pressure equalizing tank and / or adjusting the pressure of the second gas in the second pressure equalizing tank to maintain the first and second liquid levels at equal heights. In another example, a first outlet / inlet gas port for transferring the first gas to or from the first pressure equalizing tank is located above the first liquid level, and a first valve is connected to the first outlet / inlet gas port, and by operating the first valve, the pressure of the first gas in the first pressure equalizing tank is adjusted to change the height of the first liquid level. In yet another example, a second outlet / inlet gas port for transferring the second gas to or from the second pressure equalizing tank is located above the second liquid level, and a second valve is connected to the second outlet / inlet gas port, and by operating the second valve, the pressure of the second gas in the second pressure equalizing tank is adjusted to change the height of the second liquid level.

[0241] In another example, the first valve and / or the second valve can be operated automatically using one or more programmable logic controllers. One or more programmable logic controllers can also monitor the heights of the first and second liquid levels using one or more sensors. The pressures of the first gas and the second gas can be maintained at a constant differential pressure by maintaining a constant height difference between the first and second liquid levels. Preferably, the volume of the first liquid in the first pressure equalization tank is greater than the volume of the first gas in the cell or cell stack, as well as the first headspace of the first pressure equalization tank and the first gas conduit. Also preferably, the volume of the second liquid in the second pressure equalization tank is greater than the volume of the second gas in the cell or cell stack, as well as the second headspace of the second pressure equalization tank and the second gas conduit.

[0242] Exemplary Embodiments In one exemplary embodiment, the cell or cell stack 210 is an electrosynthetic liquid gas water electrolytic cell, where gas 1 (first gas) is oxygen and gas 2 (second gas) is hydrogen, both produced from water by the electrolytic cell. The gas equalization system 401 can provide very precise equalization in such an electrolytic cell, to the extent that it maintains an average pressure difference of about 1 millibar when the total absolute pressure of each gas is about 30 bar. This is thought to be partly because the first liquid 470 / second liquid 473 in each equalization tank has a clearly defined and essentially invariant density and compressibility during operation, unlike the gas-filled liquid, foam or foam in the separation tanks 35 and 45 discussed in the prior art example of Figure 1 and related descriptions. Furthermore, each of the first liquid level 471 and the second liquid level 472 is clearly defined and distinct at their interface with the gas in the headspaces 450, 460 of the first equalization tank 410 and the second equalization tank 420, respectively. This is in contrast to the "liquid level" in the separation tanks 35 and 45 described in the example of the conventional technology shown in Figure 1, where the liquid diffuses without being very defined due to the presence of numerous bubbles at the liquid-gas interface.

[0243] The well - defined and essentially invariant densities and compressibilities of the first liquid 470 / second liquid 473 provide a method for maintaining equal pressures of gas 1 and gas 2, together with well - defined and distinct first liquid level 471 and second liquid level 472 in the first equalizing tank 410 and second equalizing tank 420 respectively. The method includes maintaining the first liquid level 471 of the first liquid 470 and the second liquid level 472 of the second liquid 473 in the first equalizing tank 410 and the second equalizing tank 420 at equal heights. This is achieved by controlling the opening and closing of the first valve (V A ) 480 and the second valve (V B ) 490 so as to maintain the first liquid level 471 of the first liquid 470 and the second liquid level 472 of the second liquid 473 in the first equalizing tank 410 and the second equalizing tank 420 at equal heights. The operation of valves V A and V B may be automatically controlled, for example, by a balance - of - plant PLC that simultaneously monitors in real - time sensors that detect the heights of the first liquid level 471 and the second liquid level 472.

[0244] In another exemplary method, the pressure of gas 1 and the pressure of gas 2 are maintained at a fixed differential pressure by similarly maintaining the first liquid level 471 and the second liquid level 472 in the first equalizing tank 410 and the second equalizing tank 420 at a fixed height difference.

[0245] (1)(iii) Gas management: Gas pressure control In various exemplary aspects, embodiments relate to a balance - of - plant for an electrosynthesis or electro - energy liquid - gas cell or cell stack with novel and / or improved gas pressure control, or a method of operation.

[0246] In one example, referring to FIG. 8, a gas pressure control system 402 is provided for the balance of plant of an electro-synthesis or electro-energy liquid gas cell or cell stack 210, which uses two valves, a coarse adjustment valve and a fine adjustment valve, arranged in series (i.e., in-line) in an external inlet or outlet gas pipe to manage the gas pressure within the attached cell or cell stack. Preferably, the valves are controlled by an automatic control system, such as a PLC of the balance of plant.

[0247] FIG. 8 shows the pressure equalization system of FIG. 7, with two such valves attached in series to the gas pipes for each of gas 1 and gas 2. As seen in FIG. 8, the pressure control valves V A 480 (gas 1) and V B 490 (gas 2) are replaced, respectively, by two valves, namely, the "fine" control valves V F , 481 (gas 1) and the "fine" control valve V F , 491 (gas 2), that is, the "fine control valve for the first gas" 481 and the "fine control valve for the second gas" 491, which effect a relatively small adjustment of the gas pressure, and the "coarse" control valves V C , 482 (gas 1) and the "coarse" control valve V C , 492 (gas 2), that is, the "coarse control valve for the first gas" 482 and the "coarse control valve for the second gas" 492, which effect a relatively large adjustment of the gas pressure at each gas inlet / outlet. Between each fine control valve V F , 481 (gas 1) and 491 (gas 2) and the cell or cell stack, there also exists an adjacent gas volume, which is designated as having pressures P fine (gas 1) and P fine (gas 2). The pressures P [[ID=X]] fine (gas 1) and P fine (gas 2) are generally close to or the same as the respective pressures of gas 1 and gas 2 within the attached cell or cell stack, which pressures are respectively P stack (gas 1) and P stack(Gas 2) is called the first buffer gas volume section 432 (Gas 1) and the second buffer gas volume section 442 (Gas 2), respectively, which are called "buffer" volume sections. F , 481 (gas 1) and 491 (gas 2) and each coarse control valve V C Further exists between 482 (gas 1) and 492 (gas 2). The pressures within the buffer volume section, i.e., within the first buffer gas volume section 432 (gas 1) and the second buffer gas volume section 442 (gas 2), are P coarse (Gas 1) and P coarse This is called (gas 2). For each of gas 1 and gas 2, pressure P coarse Generally, P fine It may be to a similar degree, and does not have to be significantly different. That is, the pressure difference from one side to the other across each micro-control valve, i.e., ΔP = P coarse -P fine This can generally be small. The first buffer gas volume section 432 (gas 1) and the second buffer gas volume section 442 (gas 2) are shown as tubes in Figure 8, but they may be larger volume sections, for example, they may incorporate tanks, i.e., buffer tanks.

[0248] The inventors have found that a small pressure difference (ΔP) across a PLC-controlled valve can allow for more precise and accurate adjustment of the pressure on the cell stack side of the valve than a larger pressure difference across the same valve can. That is, the (fine) control valve in the above configuration can be opened and closed in a more controlled and precise manner under PLC control when there is a small pressure difference (ΔP) across it than when there is a large pressure difference across it. Such a small pressure difference can be created by placing another control valve—a (coarse) control valve—in series with the (fine) control valve, outside the cell stack. Therefore, by incorporating two control valves in series, namely a fine and a coarse control valve, at the external inlet / outlet of the gas pipe, the pressure P fine This can create the capability for more precise automatic adjustment. Furthermore, pressure P fine The ability to adjust the pressure P within the cell or cell stack for more precise adjustments is also important.stack This provides more precise adjustments.

[0249] In other words, the "fine" control valve V shown in Figure 8 is used to make relatively small adjustments to the gas pressure. F , 481 (gas 1) and 491 (gas 2) (i.e., "fine control valve for the first gas" 481 and "fine control valve for the second gas" 491), as well as "coarse" control valve V used to make relatively large adjustments to the gas pressure at each gas inlet / outlet. C The presence of 482 (gas 1) and 492 (gas 2) (i.e., “coordinate control valve for first gas” 482 and “coordinate control valve for second gas” 492) results in better control of the pressure of each gas in the electrosynthesis or electroenergy liquid gas cell or cell stack.

[0250] This can be achieved, for example, by a fully automated process using a programmable logic controller (PLC) that controls the fine control valve and the coarse control valve while simultaneously monitoring (i) the gas pipe between the fine control valve and the coarse control valve, (ii) the gas pipe between the fine control valve and the cell or cell stack, and (iii) pressure detectors / sensors positioned within the cell or cell stack.

[0251] Preferably, the pressure difference across one or both of the microcontrol valves, i.e., ΔP=P coarse -P fine This is less than 0.001 bar, less than 0.002 bar, less than 0.003 bar, less than 0.005 bar, less than 0.010 bar, less than 0.020 bar, less than 0.040 bar, less than 0.050 bar, less than 0.075 bar, less than 0.100 bar, less than 0.125 bar, less than 0.150 bar, less than 0.200 bar, less than 0.300 bar, less than 0.400 bar, less than 0.500 bar, less than 0.750 bar, less than 1 bar, less than 2 bar, less than 5 bar, less than 10 bar, or less than 20 bar.

[0252] Preferably, a fine control valve and a cell stack, P fine and P stackThe pressure difference between one or both is less than 0.001 bar, less than 0.002 bar, less than 0.003 bar, less than 0.005 bar, less than 0.010 bar, less than 0.020 bar, less than 0.040 bar, less than 0.050 bar, less than 0.075 bar, less than 0.100 bar, less than 0.125 bar, less than 0.150 bar, less than 0.200 bar, less than 0.300 bar, less than 0.400 bar, less than 0.500 bar, less than 0.750 bar, less than 1 bar, less than 2 bar, less than 5 bar, or less than 10 bar.

[0253] While the use of coarse and fine control valves has been described above, as applied to the pressure equalization system in Figure 7, it should be understood that this can be similarly applied to any other pressure equalization system, including, for example, the pressure equalization systems shown in Figures 5 and 6.

[0254] Furthermore, while the coarse control valve is positioned outside the fine control valve along the gas line in Figure 8, it should be understood that any order can be used. For example, the fine control valve may be positioned outside the coarse control valve in the exemplary gas line.

[0255] (1)(iv) Gas circulation or recirculation, including during “standby” All of the embodiments and examples described above had a single gas conduit route for each individual and separate gas entering and leaving the cell or cell stack. Since the gas entering through such a conduit has no route to leave the cell or cell stack, such a connection is referred to in the industry as a “dead end” connection. However, in many cases, particularly with many electrical energy cells, individual and separate gases need to circulate through the cell, and a “dead end” connection cannot be operated safely.

[0256] In various exemplary embodiments, embodiments relate to a balance of plant or operating method for an electrosynthesis or electroenergy liquid gas cell or cell stack that can circulate or recirculate gas through a cell or cell stack, including but not limited to the purpose of maintaining a “standby” state. “Standby” is a state in which the cell or cell stack is not operating but is available for immediate starting without going through the steps normally included in a starting procedure.

[0257] In many electroenergy liquid gas cells, when two or more separate gases in bulk form are introduced into the cell, contaminants begin to accumulate within those bulk gases in the cell. This can be due to gas crossover, where gas from one side of the inter-electrode separator membrane / ionomer moves to the other side, contaminating each gas on the other side. Such gas crossover can systematically accumulate contaminants in each gas over time. Similarly, in many electrosynthetic liquid gas cells containing two or more separate bulk gases, disconnecting the power connection to stop operation can cause contaminants to begin accumulating within those bulk gases in the cell. Contaminant accumulation can be problematic because, for example, (i) it creates a safety hazard, (ii) it violates gas purity specifications, making it unacceptable for the gas-supplied customer to have bulk gases in the cell or cell stack, and / or (iii) when the cell or cell stack is restarted, the bulk gases in the cell or cell stack may become excessively impure and unsuitable for use as reactants. In such cases, the accumulation of contaminants may effectively require a complete shutdown process in which the cell or cell stack is purged with an inert gas. This may then require a complete startup process before operation can be resumed.

[0258] A non-limiting example in this regard is the electrosynthesis liquid gas water electrolysis cell. As mentioned above, such a cell typically produces two gases, namely hydrogen (at the cathode) and oxygen (at the anode). The hydrogen and oxygen product streams are typically kept separate by a separator membrane / ionomer placed between the electrodes. Such a separator membrane or ionomer generally slows down, but does not stop, the rate at which hydrogen gas moves across the separator into the oxygen stream, and the rate at which oxygen gas moves across the separator into the hydrogen stream; this is known as gas crossover. When such a cell is disconnected from its power connection, it stops producing hydrogen and oxygen gases. However, the rate of gas crossover continues without reduction. Therefore, hydrogen contaminants in the bulk oxygen body within the cell can accumulate over time. Oxygen contaminants in the bulk hydrogen within the cell can also accumulate over time. As mentioned above, this can be problematic because oxygen containing more than about 4% hydrogen, or hydrogen containing more than about 4% oxygen, is an explosive mixture at the normal operating temperature of 80°C. This can be particularly problematic in water electrolysis cells, such as the type shown in Figure 2, which have permanent liquid-gas-solid state boundaries at each electrode. Large chunks of bulk hydrogen and bulk oxygen can be present inside such cells.

[0259] The inventors have found that by continuously, continuously, or periodically recirculating a separate bulk gas within the cell via an external device that removes contaminants, it is possible to constantly remove contaminants from the hydrogen and oxygen within the cell, thereby ensuring their safety even after power is cut off from such a cell. The device that removes hydrogen from an oxygenated body is referred to herein as a “recombiner.” The device that removes oxygen from a hydrogenated body is referred to herein as a “deoxo” unit.

[0260] Similarly, gases introduced into an electrical energy liquid gas cell, such as hydrogen and oxygen introduced into a hydrogen-oxygen fuel cell, can be safely maintained if both gases are continuously, continuously, or periodically recirculated through a device that removes pollutants originating from the gas crossover.

[0261] Therefore, a balance of plant or operating method is provided for an electrosynthesis or electroenergy liquid gas cell or cell stack that continuously, continuously, or periodically recirculates one or more bulk gases from the cell or cell stack through a "decontamination" unit back to the cell or cell stack. Such recirculation can enable the cell or cell stack to remain safe even when the balance of plant is in a "standby" state when the power connection is disconnected.

[0262] In some cases, the standby state may be implemented independently of the initiation of gas recirculation through the cell or cell stack. For example, gas recirculation through the cell or cell stack may be initiated only after the standby state is implemented if there is a risk that the level of contaminated gas in the gas body will become dangerous. Similarly, gas recirculation through the cell or cell stack may be stopped when the level of contaminated gas in the gas body has decreased sufficiently.

[0263] In other examples, gas recirculation through the cell or cell stack begins when the standby state is activated, i.e., when the power connection to the cell or cell stack is disconnected. In yet another example, gas recirculation through the cell or cell stack stops when the standby state is shut down, i.e., when the power connection to the cell or cell stack is engaged.

[0264] Figure 9 shows a gas recirculation system 500 of the type described above. An electrosynthesized or electroenergy liquid gas cell or cell stack 210 is optionally incorporated into a pressure vessel 220, which optionally contains an annular liquid 250 or annular gas 255 between the outer wall of the cell or cell stack 210 and the inner wall of the pressure vessel 220 (not shown in Figure 9), as described in Figures 3-4 and related text. The cell or cell stack 210 contains a bulk form of gas that is gradually contaminated, for example, when the cell or cell stack 210 is disconnected from its power connection during a “standby” state. To avoid the accumulation of contaminants, the bulk gas is preferably, but not exclusively, drawn out of the cell or cell stack 210 in direction 520a along a pipe 550 by an ejector, E, 560 or similar device. The gas then enters a “decontamination unit” 510 in direction 520a along a pipe 551. Preferably, but not exclusively, the decontamination unit 510 may include a porous packed bed of a catalyst or adsorbent 520 that removes contaminants from the circulating gas. As the gas passes through the decontamination unit 510, contaminants in the gas are removed by the catalyst or absorbent bed 520. The gas then exits the decontamination unit 510 into a pipe 540 in direction 520a. Preferably, but not exclusively, the gas is instead circulated back into the cell or cell stack 210 by a fan F, 530, which may be a blower, compressor, or any similar engineering component capable of moving a gaseous fluid. The gas is propelled in direction 520a through a pipe 541 and returns to the cell or cell stack 210.

[0265] In one example, the gas recirculation system 500 through the cell or cell stack 210 may be started when the electrosynthesis or electroenergy liquid gas cell or cell stack 210 is turned off, i.e., when its power connection is disconnected. Preferably, the gas recirculation through the cell or cell stack 210 is stopped when the power connection of the electrosynthesis or electroenergy liquid gas cell or cell stack 210 is engaged.

[0266] Optionally, if the cell or cell stack 210 includes two or more distinct gas streams, the balance of plant can provide two or more distinct recirculation loops, each incorporating a suitable contaminant removal unit and other components as described above. In such a case, preferably, but not exclusively, both recirculation loops may be turned on when the electrosynthesis or electroenergy liquid gas cell or cell stack 210 is turned off, i.e., when the power connection is disconnected. Preferably, but not exclusively, both recirculation loops can be stopped when the power connection of the electrosynthesis or electroenergy liquid gas cell or cell stack 210 engages.

[0267] In an exemplary embodiment, the electrosynthesis or electroenergy liquid gas cell or cell stack 210 is of a water electrolyzer or a hydrogen-oxygen fuel cell, which includes two distinct gas streams, namely a stream of oxygen and a stream of hydrogen. Preferably, but not exclusively, a contaminant removal unit called a recombiner continuously removes contaminant hydrogen that accumulates in the oxygen gas stream within the cell or cell stack 210 during standby, thereby ensuring that the oxygen stream remains safe. Preferably, but not exclusively, a contaminant removal unit called a deoxo unit continuously removes contaminant oxygen that accumulates in the hydrogen stream within the cell or cell stack 210 during standby, thereby ensuring that the hydrogen stream remains safe. Preferably, but not exclusively, as described in Section 6 below, standby is used in a water electrolyzer or a hydrogen-oxygen fuel cell during "load following" or "grid balancing".

[0268] (2) Liquid management In various exemplary aspects, embodiments relate to a balance of plant or method of operation for an electrosynthesis or electroenergy liquid gas cell or cell stack with novel and / or improved liquid management.

[0269] Pumps have been widely used to move liquids within electrosynthetic or electroenergy liquid gas cells and cell stacks, but the inventors have found that ejectors offer improved operation under certain circumstances. This is particularly true for cells that are not exclusively but only partially filled with liquid, such as the type of cell shown in Figure 2. Because such cells are not completely filled with liquid, the conventional method of using pumps to pressurize large amounts of liquid through the cell can be problematic, at least in terms of ensuring a constant liquid level within the cell. Using ejectors to draw liquid out of the cell while simultaneously using pumps to pressurize liquid into the cell can provide a more effective and controlled means of circulating liquid through such cells. In such cases, the tank through which the liquid circulates may be optimally positioned below the height of the cell and cell stack, rather than above it.

[0270] Accordingly, a liquid circulation system or method for the balance of a plant of electrosynthesis or electroenergy liquid gas cells or cell stacks is provided, wherein the liquid is circulated through the cells or cell stack by being drawn out of the cells or cell stack using an ejector or similar component. Preferably, gravity can assist the ejector or similar component in drawing the liquid out of the cells or cell stack, although this is not exclusive.

[0271] - Basic liquid circulation system Figure 10 shows a liquid circulation system 600 in which liquid is circulated through the cell or cell stack 210 by being drawn out of the cell or cell stack 210 using, for example, an ejector, E, 660, or a similar component such as a pump. The electrosynthesis or electroenergy liquid gas cell or cell stack 210 is optionally incorporated into a pressure vessel 220, and optionally, as described in Figures 3-4 and related text, an annular liquid 250, which may be water, for example a cooling liquid 250, or an annular gas 255, is incorporated between the outer wall of the cell or cell stack 210 and the inner wall of the pressure vessel 220 (not shown in Figure 10). That is, the liquid outlet pipe 650 of the cell or cell stack 210 is connected to a liquid circulation tank 610, and the liquid 620 is drawn out of the cell or cell stack 210 via the liquid outlet pipe 650 by the ejector E, 660. The liquid 620 drawn out of or pumped out of the cell or cell stack 210 may be a liquid electrolyte or a cooling liquid.

[0272] The cell or cell stack 210 contains a liquid 620, such as a liquid electrolyte or coolant, and the liquid is drawn out by an ejector E, 660 via a liquid outlet pipe 650. The liquid 620 travels along pipe 651 in direction 620a and enters a liquid circulation tank 610, which may be partially or completely filled with the liquid 620. From the liquid circulation tank 610, the liquid 620 can be pumped (or drawn in by an ejector) by a pump P, 630 and return to the cell or cell stack 210 in direction 620a via one or more pipes, such as pipes 640 and 641. Thus, the cell or cell stack 210 is provided with a liquid outlet pipe 650 connected to the liquid circulation tank 610, and the liquid 620 is drawn out of the cell or cell stack 210 by an ejector 660 or a pump. The liquid 620 is pumped back from the liquid circulation tank 610 to the cell or cell stack 210 via one or more pipes by a pump 630 or a similar component such as an ejector. The liquid circulation tank 610 is optionally located below the cell or cell stack 210.

[0273] The annular liquid 250 surrounding the cell or cell stack 210 can be similarly but separately circulated from the pressure vessel 220 to a separate liquid circulation tank and returned to the pressure vessel 220.

[0274] Preferably, liquid 620 is added to or removed from the liquid circulation system 600 by adding or removing liquid from the liquid circulation tank 610. The liquid added or removed may be the same as liquid 620, or a different liquid 690, for example, water added to or removed from the aqueous liquid electrolyte 620. Preferably, but not exclusively, liquid 620 or a different liquid 690 is added to or removed from the liquid circulation system 600 via the liquid addition / removal port 670 of the liquid circulation tank 610.

[0275] When the liquid circulation tank 610 is completely filled with liquid 620, the pressure of the liquid 620 in the liquid circulation tank 610 is preferably controlled via the pressure port 671 of the liquid circulation tank 610. Preferably, the pressure port 671 is in contact with a pressure control device that controls the pressure 680 applied to the liquid 620, such as an expansion tank of the type described in Figure 4 and related text. Optionally, the pressure port 671 may also be a liquid addition / removal port 670.

[0276] It should be understood that the pump P, 630 shown in Figure 10 can be replaced by the ejector E, 660, and vice versa. That is, the ejector E, 660 shown in Figure 10 can be replaced by the pump. Similarly, the pump P, 630 shown in Figure 10 can be replaced by the ejector.

[0277] - Liquid circulation system integrated with a gas pressure equalization system and a gas pressure control system. When the liquid circulation tank is only partially filled with liquid, the headspace is preferably filled with gas, and the pressure of the liquid in the tank is controlled by controlling the pressure of the gas in the headspace. Figure 11 shows an example of such a system 700, which also - A gas pressure equalization system utilizing the type of pressure equalization tank shown in Figures 5-6 and 7 and related text, and - A pressure control system utilizing the types of coarse and fine back pressure valves shown in Figure 8 and the related text. It will be incorporated into it. In other words, the liquid circulation tank includes a gas headspace of the type used for pressure equalization in Figures 5-6 and 7 and related text, and back pressure control utilizes fine and coarse valves as described in Figure 8 and related text.

[0278] The electrosynthetic or electroenergy liquid gas cell or cell stack 210 is optionally incorporated into a pressure vessel 220, and optionally, an annular liquid 250, which may be water, or an annular gas 255 is incorporated between the outer wall of the cell or cell stack 210 and the inner wall of the pressure vessel 220 (not shown in Figure 11), as described in Figures 3-4 and related text.

[0279] The liquid circulation system 700 includes a pipe 650 through which liquid 720 is drawn from the cell or cell stack 210 by an ejector E, 660 and guided along the pipe 651 in direction 620a into a liquid circulation tank 710 that is partially filled with liquid 720. In this case, the headspace of the liquid circulation tank 710 above the liquid level 721 is filled with gas 705, i.e., “circulation tank gas” 705, which is also present in bulk form inside the cell or cell stack 210. In this example, gas 705 may be a first gas or a second gas generated or consumed by the cell or cell stack 210. Gas 705 (i.e., “circulation tank gas” 705) can pass through the liquid 720 in the liquid circulation tank 710 on its way to or from the cell or cell stack 210. As the gas 705 passes between the cell or cell stack 210 and the headspace of the liquid circulation tank 710, it passes along the gas conduit 730 (including arm 730a) in one direction 705a. As the gas 705 passes between the headspace of the liquid circulation tank 710 and the external environment, it passes along the pipes 740, 741, and 742 via the fine control valve 750 and coarse control valve 760, which are arranged in series. The fine control valve 750 and coarse control valve 760 can control the pressure of the gas 705 in the headspace of the liquid circulation tank 710 above the liquid level 721. These valves can also control the pressure of the liquid 720 in the liquid circulation tank 710. The liquid in pipe 651 has the same pressure as the liquid 720 in the liquid circulation tank 710, including the point 721 where the liquid in pipe 651 enters the liquid circulation tank 710 (as the gas 705 passes through the headspace above the liquid level 721).

[0280] Therefore, this embodiment can be combined with a liquid circulation system, a pressure equalization system of the type described in Figures 5-6 and 7 and related text, and a pressure control system using coarse and fine back pressure valves of the type described in Figure 8 and related text. The pressure of the gas 705 in the cell or cell stack 210 can be controlled by the coarse and fine valves, and the headspace of the liquid tank 710 acts as a buffer volume to facilitate equalization of the pressure of the gas 705 with the pressure of another gas present in bulk form in the cell or cell stack 210. If the liquid 720 is also the liquid electrolyte in the cell or cell stack 210, the system 700 can facilitate equalization of the pressure of a separate bulk gas present in the cell or cell stack 210, as well as equalization with the pressure of the liquid electrolyte in the cell or cell stack 210.

[0281] Preferably, but not exclusively, the liquid circulation tank 710 is lower than the level of the cell or cell stack 210c relative to gravity, preferably completely lower, i.e., the liquid circulation tank 710 is preferably, but not exclusively, an "infrastructure" tank. Preferably, but not exclusively, the liquid passing along the pipe 651 in direction 620a falls into the tank 710 through the gas head space, as shown in 721.

[0282] Preferably, pressure is transmitted directly to the inter-electrode separator membrane / ionomer by the gas and not through a column of mixed liquid electrolyte and gas two-phase mixtures, as found in conventional electrolytic cells (as described in Figure 1 and related text). This avoids high gas crossover due to fluctuations and transient pressure differences across the separator.

[0283] Preferably, the liquid is added to or removed from the liquid circulation system in 700 by adding or removing liquid to or from the liquid circulation tank 710 via port 770. The liquid added or removed may be the same as liquid 720, or a different liquid 780, for example, water 780 added to or removed from the aqueous liquid electrolyte 720.

[0284] This example shows that the gas in headspace is the bulk gas, i.e., the primary or secondary gas, that is also present in the cell or cell stack. However, it should be understood that any gas, including a gas different from the gas present in the cell or cell stack, can be used in headspace.

[0285] - Parallel liquid circulation system If a cell or cell stack includes two or more separate liquid flows, such as an anode liquid flow and a cathode liquid flow, the balance of plant may optionally provide two or more separate liquid circulation systems. Such a configuration is referred to herein as a “parallel liquid circulation system”.

[0286] Each circulation system may optionally incorporate a separate ejector or similar component capable of moving the liquid phase fluid. Optionally, each liquid circulation system may also incorporate a separate liquid-filled tank or a partially filled tank from which the fluid can be pumped back into a cell or cell stack, preferably, but not exclusively, by a pump.

[0287] If a separate liquid circulation tank is included that is only partially filled with liquid, the headspace above the liquid level in each tank may be filled with gas. Optionally, the gas in each headspace may be a different gas from the gas present in the cell or cell stack, or the gas in each headspace may be the same gas as the gas present in bulk in the cell or cell stack. Optionally, the gas in each headspace may be fluidly connected to the same gas in the cell or cell stack via a gas conduit between the headspace and the inlet / outlet of the same gas in the cell or cell stack. Optionally, the pressure of the gas in each headspace may be the same as or substantially the same as the pressure of the same gas in the cell or cell stack. Optionally, the pressure of the gas in each headspace can be controlled by coarse and fine control valves positioned sequentially (in series) on gas lines attached to the liquid circulation tank, as described in Figure 8 and the related text.

[0288] If there are two separate, partially filled liquid circulation tanks, each of which has its headspace filled with a separate gas that is fluidly connected to the same gas in bulk form inside the cell or cell stack, then the two liquid circulation tanks can simultaneously function as equalizing tanks of the type described in Figure 6 and the related text. Furthermore, if the two liquid circulation tanks contain the same liquid electrolyte and are fitted with a "connecting pipe", they can function as an equalizing system of the type described in Figure 7 and the related text. In such cases, the two liquid circulation tanks may also serve as an equalizing system. Preferably, but not exclusively, the two separate liquid circulation tanks that also serve as equalizing tanks are "infrastructure" tanks, i.e., they are below the level of the cell and / or cell stack.

[0289] Optionally, two liquid circulation flows in a parallel liquid circulation system may be combined into a single liquid flow at a point along each liquid circulation path, and then separated again into two liquid flows at another point. For example, a single ejector or similar component can optionally draw both liquid flows from the cell or cell stack, thereby combining the flows at the point where they exit the cell or cell stack. Alternatively, or additionally, the two liquid flows may be combined into a single liquid flow at the point where each flow is fed into a single liquid circulation tank. Alternatively, or additionally, the two liquid flows may be drawn from two separate liquid circulation tanks by a single pump that combines them into one. The combined liquid flow may be separated again into two flows at a point along the liquid circulation path before re-entering the cell or cell stack.

[0290] - Gas head space of other parts of the liquid circulation system Optionally, the liquid outlet pipe 650a of the cell or cell stack 210 in Figure 11 is also connected to the ejector 660 at the other end and may contain a gas headspace. Optionally, the gas in that headspace may be gas 705, which is also present in the cell or cell stack 210. Optionally, the headspace of the liquid outlet pipe 650a of the cell or cell stack 210 may be physically connected to the inlet / outlet 730a of that gas 705 in the cell or cell stack 210 via a connecting gas pipe equipped with a suitable orifice or similar "pressure drop" device.

[0291] Figure 12 shows such a configuration in a schematic cross-sectional view. The liquid outlet pipe 650a of the cell or cell stack 210 contains the liquid 720 and the headspace of gas 705 above the liquid level 790. Due to the effect of ejector E, 660, the pressure in pipe 650a is necessarily lower than the pressure in pipe 730a when the configuration shown in Figure 11 is used. The gas 705 fills the headspace in pipe 650a above the liquid level 790 and fluidly connects to pipe 795, which connects the liquid outlet 650a to the gas inlet / outlet 730a of the cell stack 210, via an orifice 796 or similar "pressure reducer" 796. The orifice 796 or similar pressure reducer 796 is required because, due to the effect of ejector E, 660, the pressures of the liquid 720 and gas 705 inside pipe 650a are lower than the pressure of the gas 705 inside pipe 730a. Such a configuration can be used at either the end of a cell or a cell stack 210.

[0292] In another example, the gas 705 in the tube 650a and the liquid 720 can be mixed to create some bubbles of gas 705 in the liquid 720, that is, the tube 650a may be filled or partially filled with foam or bubbles of the mixed gas and liquid. In this case, preferably, there is no connecting gas tube 795 between the tube 650a and the tube 730a.

[0293] Gravity can partially assist the liquid at the bottom of the liquid outlet pipe 650a in falling downwards as the liquid 720 enters the pipe 650 in Figure 11.

[0294] - Exemplary embodiments of water electrolytic cells / hydrogen-oxygen fuel cells In exemplary embodiments, the electrosynthesis or electroenergy liquid gas cell or cell stack is a water electrolytic cell or hydrogen-oxygen fuel cell that can include two separate liquid flows, namely an oxygen-side liquid electrolyte flow and a hydrogen-side liquid electrolyte flow. Preferably, but not exclusively, the balance of plant includes two separate liquid circulation systems, one for the oxygen-side liquid electrolyte flow and one for the hydrogen-side liquid electrolyte flow, with each liquid circulation system separately incorporating an ejector or similar component. Preferably, but not exclusively, each liquid circulation system incorporates a separate liquid circulation tank partially filled with liquid, along with a headspace for containing the gas, where, in the case of the oxygen-side liquid electrolyte circulation tank, the gas is oxygen entering and leaving the cell or cell stack, and in the case of the hydrogen-side liquid electrolyte circulation tank, the gas is hydrogen entering and leaving the cell or cell stack.

[0295] Figure 13 schematically shows one of the above liquid circulation systems, which incorporates a gas control system and a water distribution / removal system, in an exemplary embodiment of a water electrolytic cell or fuel cell 800.

[0296] The cells or cell stack 210 of a water electrolytic cell or fuel cell are incorporated into a pressure vessel 220 containing annular liquid water 250 between the outer wall of the cell stack 210 and the inner wall of the pressure vessel 220. The liquid water 250 enters the pressure vessel 220 through an inlet 251 and exits the pressure vessel 220 through an outlet 252 which becomes a pipe 252a. The liquid water 250 may be pressurized to a pressure similar to that inside the cell stack 210.

[0297] The liquid circulation system in Figure 13, which is either an oxygen-side liquid electrolyte or a hydrogen-side liquid electrolyte, comprises a tube 650 including an arm 650a through which liquid 720 is drawn from the cell stack 210 by an ejector E, 660 and led along tube 651 in direction 620a to a liquid circulation tank 710 partially filled with liquid 720. The headspace of the liquid circulation tank 710 above the liquid level 721 is filled with gas 705, which is either hydrogen or oxygen, and is also present in the cell or cell stack 210. Gas 705 passes over the liquid 720 in the liquid circulation tank 710 on its way to or from the cell stack 210. As it passes between the cell or cell stack 210 and the headspace of the liquid circulation tank 710, the gas passes along gas conduits 730 and 730a in one direction 705a. As the gas passes between the headspace of the liquid circulation tank 710 and the external environment, it passes along pipes 740, 741, and 742 via fine control valves 750 and coarse control valves 760, which are arranged in series. The fine control valves 750 and coarse control valves 760 control the pressure of the gas 705 in the headspace of the liquid circulation tank 710 above the liquid level 721. At the same time, these valves also control the pressure of the liquid 720 in the liquid circulation tank 710, which is either the oxygen-side liquid electrolyte or the hydrogen-side liquid electrolyte.

[0298] In the case of a water electrolytic cell, makeup water to replenish the water consumed in the cell or cell stack 210 is preferably, but not exclusively, added to one or both of the oxygen-side or hydrogen-side liquid circulation tanks from water (i.e., annular liquid 250) passing between the cell or cell stack 210 and the wall of the pressure vessel 220. That is, the water (i.e., annular liquid 250) exits the pressure vessel 220 via pipes 252 and 252a in Figure 13 and is then distributed to the liquid circulation tank 710 to replenish the water consumed in the cell or cell stack 210.

[0299] In the case of a hydrogen-oxygen fuel cell, the water produced by the reaction is preferably, but not exclusively, removed from the liquid circulation tank 710 by a suitable process, such as steam condensation. Figure 13 shows a water removal container 830 attached to the liquid circulation tank 710, which includes a condenser column 840. Steam in the gas 705 condenses in the cooled condenser column 840 and is collected as liquid water (i.e., annular liquid 250) at location 850, where it exits the water removal container 830 (and the entire liquid circulation system) via a tube 860. Such water (i.e., annular liquid 250) can be cooled separately and then enter the pressure vessel 220 through port 251 to cool the cell or cell stack 210. Alternatively, any other water removal system may be used and should be understood to be still within the scope of this specification.

[0300] Figure 13 shows one of the liquid circulation systems and associated pressure equalization and pressure control systems in an exemplary embodiment of the water electrolytic cell or fuel cell described above. Figure 12 may show either a hydrogen-side liquid circulation system and hydrogen pressure equalization and pressure control system, or an oxygen-side liquid circulation system and oxygen pressure equalization and pressure control system, connected to a cell or cell stack 210 inside the pressure vessel 220. In either case, the other liquid circulation system and associated gas management system must also be connected to a cell or cell stack 210 in the pressure vessel 220. The other liquid circulation system and associated gas management system are identical to those shown in Figure 13, except that they preferably include the flow of other gases and their associated liquids, and the other liquid circulation tank (not shown in Figure 12). The same liquid electrolyte, for example, a 30 wt% aqueous KOH solution, is preferably circulated in both liquid circulation systems; that is, liquid 720 and the other liquid are preferably the same. Furthermore, the two liquid circulation tanks may be separated from each other to provide the type of pressure equalization described in Figure 5 and the related text, or the two liquid circulation tanks may be connected to each other by a liquid-filled “connecting pipe” to provide the type of pressure equalization described in Figure 7 and the related text. Thus, the two liquid circulation tanks preferably also function as pressure equalization tanks, maintaining the hydrogen gas pressure equal to the oxygen gas pressure in the cell or cell stack 210. The liquid pressures in the hydrogen-side liquid circulation system and the oxygen-side liquid circulation system can then also be equalized, or equalized to the gas pressure. That is, the liquid circulation tanks preferably also function as pressure equalization tanks, thereby providing economics in the utilization of components in the balance of the plant. Preferably, the two liquid circulation tanks, which are not exclusive but subsequently function as pressure equalization tanks, are “infrastructure” tanks below the level of the cell or cell stack 210, preferably completely below it.

[0301] A single liquid circulation tank can be used for both the hydrogen-side and oxygen-side liquid circulation systems, and it should be understood that the liquid flows merge before entering the tank and split after being removed from the tank. The headspace gas in such a single tank may be either oxygen or hydrogen, and the other gas is regulated via piping similar to components 440, 440a, and 490 in Figure 5 or components 441, 442, 443, 491, and 492 in Figure 8.

[0302] (3) Cooling management of cells or cell stacks In various exemplary embodiments, the embodiments relate to a balance of plant or operating method for electrosynthesis or electroenergy liquid gas cells or cell stacks, equipped with novel and / or improved cell or cell stack cooling management. Such novel cooling systems are particularly useful for cells or cell stacks with minimal cooling requirements, such as the cell in Figure 2, as they can potentially provide all or almost all of the cooling required for such systems.

[0303] In one example, the inventors have found that a cell or cell stack can be cooled using an annular liquid that passes between the cell or cell stack and the wall of the pressure vessel surrounding it, as described in Figures 3-4 and related text.

[0304] Specifically, referring to Figures 3 and 4, as explained in Figures 3 and 4, the simple operation of passing an annular liquid 250, such as water at ambient temperature, through port 251 into the pressure vessel 220, over the cell stack 210 operating at 80°C inside the pressure vessel 220, and then out of the pressure vessel 220 through port 252, can provide approximately 2–4 kW of cooling to the cell or cell stack 210. For a cell or cell stack 210 that requires only approximately 2–4 kW of cooling (e.g., as shown in Figure 2), such a configuration can potentially provide all the necessary cooling. If additional cooling is required, this can be achieved by actively cooling the annular liquid 250, such as water, before it flows into the pressure vessel 220 at port 251.

[0305] Furthermore, in the case of a water electrolytic cell or cell stack 210, the annular liquid 250, such as water, exiting from port 252 is heated to the operating temperature of the cell or cell stack 210 and can be added to the liquid circulation system without cooling, as shown at the bottom of tube 252a in Figure 13.

[0306] Alternatively or additionally, the inventors have found that the cell or cell stack 210 can be further cooled by cooling the circulating liquid in the liquid circulation tank 610 (Figure 10) or the liquid circulation tank 710 (Figures 11 and 13). This can be achieved by placing a cooling element within the liquid circulation tank.

[0307] In further exemplary embodiments, for example, one or more “phase change tubes” of a type commonly used in computer laptops may be placed in the above-mentioned liquid circulation tank to cool the circulating liquid therein (i.e., they may be placed in the liquid circulation tank 610 in Figure 10 or the liquid circulation tank 710 in Figures 11 and 13), or they may be used to cool the liquid passing along tubes 650, 651, 640, or 641 (Figures 10, 11 and / or 13).

[0308] In the case of hydrogen-oxygen fuel cells, which can typically generate more heat than electrolytic cells, further options include cooling the liquid 720 in the liquid circulation tank 610 (Figure 10) or liquid circulation tank 710 (Figures 11 and 13) by condensing the annular liquid 250, e.g., water, and removing the annular liquid 250, e.g., water, as described in the text related to Figure 13.

[0309] In examples of electrosynthesis or electroenergy liquid gas cells or cell stacks having two separate liquid circulation systems (e.g., a water electrolytic cell or a hydrogen-oxygen fuel cell or aqueous oxygen side electrolyte flow and an aqueous hydrogen side electrolyte flow in a cell stack), it should be understood that one or both of the liquid circulation systems can be used for cooling.

[0310] (4) Monitoring and management of cell status In various exemplary embodiments, the embodiments relate to a balance of plant or operating method for electrosynthesis or electroenergy liquid gas cells or cell stacks, comprising novel and / or improved means for monitoring and controlling the state of the cells.

[0311] Generally, it is desirable to monitor the state of each cell in a cell stack, for example, by measuring the voltage and / or other information of its electrodes in real time. This can be done, for example, by attaching a high-resistance wire to each electrode of each cell and then using that wire to measure the voltage of the attached electrodes. However, in cell stacks with many cells, for example 50 or more cells, this method creates a large number of wires that need to be connected and monitored.

[0312] The inventors have found that this problem can be overcome by incorporating a computer chip or one or more computer chips within each cell, for example, by embedding a computer chip or one or more computer chips within the polymer cell frame of each cell. The computer chips can then be connected to each electrode within the cell via short, high-resistance wires. Each computer chip in each cell can then be connected to all other computer chips in other cells in the stack, and to the PLC for balance of plant, using a single common wire. Alternatively, the computer chips can include antennas that enable them to communicate wirelessly with the PLC. Each computer chip in each cell can then transmit voltage and / or other information from its cell to the PLC mounted thereon. In doing so, the numerous wires previously required can be replaced by a single common wire, or no wires can be replaced at all, which is far easier and more practical, especially when manufacturing cell stacks containing many cells in high-speed, high-volume industrial manufacturing processes.

[0313] Communication protocols that may be used in such a configuration include: (1) Program one or more chips in the cell stack to repeatedly transmit their cell information to the PLC wirelessly along a single common wire or at different times. This allows the PLC to record the voltage information and match it along the cell stack to the location of the chip that transmitted the voltage information. (2) Program one or more chips in the cell stack to transmit their information along a single common wire, or wirelessly only when polled by the PLC. That is, the PLC sends an addressed signal to each chip in the stack, and the chips respond by sending their cell information back to the PLC.

[0314] Please understand that the above communication protocols are not exhaustive. Any other communication protocols that enable the above types of configurations are included within the scope of this specification.

[0315] (5) Cell stack configuration and management In various exemplary embodiments, the embodiments relate to a balance of plant or operating method for electrosynthesis or electroenergy liquid gas cells or cell stacks, comprising novel and / or improved cell stack configurations and controls.

[0316] In one example, a cell stack is attached to a common manifold element that connects to the separate liquid and gas flows of each attached cell stack, and each manifold element accumulates the separate gas and liquid flows of the attached cell stack into a single separate external liquid and gas flow. In this way, the many separate liquid and gas flows within the attached cell stack can be reduced to a few separate external liquid and gas flows. The collection of cell stacks connected in this manner is referred to here as an "array".

[0317] Figure 14 shows a non-limiting example where the electrosynthesis or electroenergy liquid gas battery stack is a stack of a water electrolytic cell or hydrogen-oxygen fuel cell having two separate liquid flows within each cell stack, an oxygen-side liquid electrolyte flow (referred to as liquid 1) and a hydrogen-side liquid electrolyte flow (referred to as liquid 2). In addition to separate inlets / outlets for liquids 1 and 2, each cell stack also has separate inlets / outlets for oxygen (O2) gas and hydrogen (H2) gas. Such separate inlets / outlets can be present at each end of each cell stack, thereby allowing the recirculation of each separate gas or liquid through the cell stack via the inlet at one end of the cell stack and the outlet at the other end of the cell stack.

[0318] Figure 14 shows five such cell stacks assembled in parallel on an array 900 positioned on a stand 920 (this is for illustrative purposes only, and any number of cell stacks can be used). Five pressure vessels 910 (not visible in Figure 14), each containing a cell stack inside, are attached at one end to a common first manifold element 901 and at the other end to a common second manifold element 902. Each manifold element contains within it pipes attached to each of the separate inlet and outlet pipes of each cell stack (penetrating the wall of each pressure vessel at each end). Fluids flow through these separate cell stack inlet / outlet pipes of each stack, effectively combine, and accumulate in a single separate external gas and liquid flow within the attached manifold element.

[0319] Therefore, the first manifold element 901 has a single external inlet / outlet pipe 940a for oxygen (O2) gas, which connects via an internal pipe within the manifold element 901 to all oxygen inlets / outlets on the right side of each stack in the five pressure vessels 910. Similarly, the first manifold element 901 has a single external inlet / outlet pipe 950a for hydrogen (H2) gas, which connects via an internal pipe within the first manifold element 901 to all hydrogen inlets / outlets on the right side of each stack in the five pressure vessels 910. Furthermore, the first manifold element 901 has a single external inlet / outlet pipe 960a for the first circulating liquid, i.e., liquid 1, which connects via an internal pipe within the first manifold element 901 to all inlets / outlets for liquid 1 on the right side of each stack in the five pressure vessels 910. The first manifold element 901 further has a single external inlet / outlet pipe 970a for liquid 2, which is a second circulating liquid (this is hidden by the pressure vessel 910 and therefore cannot be seen in Figure 14), which connects to all inlets / outlets of liquid 2 on the right side of each stack in the five pressure vessels 910 via an internal pipe within the first manifold element 901.

[0320] Similarly, the second manifold element 902 has a single external inlet / outlet pipe 940b for oxygen (O2) gas, which connects via an internal pipe within the second manifold element 902 to all oxygen inlets / outlets on the left side of each stack in the five pressure vessels 910. The second manifold element 902 also has a single external inlet / outlet pipe 950b for hydrogen (H2) gas, which connects via an internal pipe within the second manifold element 902 to all hydrogen inlets / outlets on the left side of each stack in the five pressure vessels 910. Furthermore, the second manifold element 902 has a single external inlet / outlet pipe 960b for circulating liquid 1, which connects via an internal pipe within the second manifold element 902 to all inlets / outlets for liquid 1 on the left side of each stack in the five pressure vessels 910. The second manifold element 902 also has a single external inlet / outlet pipe 970b for circulating liquid 2, which connects via an internal pipe within the second manifold element 902 to all inlets / outlets for liquid 2 on the left side of each stack in the five pressure vessels 910.

[0321] In the example shown in Figure 14, the separate pipes in the first manifold element 901 and the second manifold element 902 are configured to provide a parallel connection of flow paths. However, it should be understood that the pipes in the manifold elements 901 and 902 may alternatively be configured to provide a series connection of flow paths, or a combination of parallel and series connections of flow paths.

[0322] Furthermore, while Figure 14 shows a cell stack in a pressure vessel connected to manifold elements 901 and 902 at each end, it should be understood that the cell stack does not necessarily have to be inside the pressure vessel. Nor does it have to be attached to manifold elements 901 and 902 at each end. Numerous different array configurations may be conceivable, and all of them may constitute an array.

[0323] Furthermore, the manifold elements may also include, or at least incorporate, power connections / wiring that provide cumulative or separate power connections to each of the cell stacks in the array. For example, in Figure 14, the second manifold element 902 houses five power connections / wires 930 that go to the left side of each individual cell stack (via their respective pressure vessels 910). The first manifold element 901 similarly houses five power connections / wires 930 (not visible in Figure 14 as they are hidden by the first manifold element 901) that go to the right side of each individual cell stack (via their respective pressure vessels 910). When separate wires are used for each power connection to each cell stack in such an array, each individual cell stack is preferably electrically activated independently, but not exclusively. When a single cable is used to power multiple cell stacks in such an array, all connected cell stacks can be electrically activated simultaneously.

[0324] Preferably, though not exclusive, each cell stack in each pressure vessel 910 within the array 900 is electrically connected to either a single non-shared power element or a shared power element connected to multiple cell stacks. The power element is preferably an inverter or similar device capable of bidirectional power management and capable of supplying power to the cell stack (when operating as a water electrolyzer) or transmitting power from the cell stack (when operating as a hydrogen-oxygen fuel cell). Preferably, though not exclusive, each such power element is automatically managed, for example, by a PLC in the balance of plant, thereby enabling rapid changes in the direction of current flow. Preferably, though not exclusive, these features, in combination with other features described in the previous paragraphs, provide a balance of plant that enables bidirectional operation of the cell stacks arranged as either water electrolyzers or hydrogen-oxygen fuel cells, i.e., as a regenerative fuel cell-electrolyzer.

[0325] Preferably, though not exclusive, the array 900 of the water electrolyzer or hydrogen-oxygen fuel cell stack is configured to allow bulk hydrogen and / or oxygen to be circulated to the cells and stack, including for the purpose of maintaining a “standby” state. That is, as described in Section 1(iv) above, the accumulated oxygen flow may be recirculated via external oxygen inlets / outlets 940a-b on manifold elements 901 and 902, and the accumulated hydrogen flow may be recirculated separately via external hydrogen inlets / outlets 950a-b on manifold elements 901 and 902, respectively.

[0326] Preferably, though not exclusive, the array 900 of the water electrolytic cell or hydrogen-oxygen fuel cell stack is configured to circulate the oxygen-side liquid electrolyte (liquid 1) separately to the outside via external liquid 1 inlets / outlets 960a~b on manifold elements 901 and 902, and to circulate the hydrogen-side liquid electrolyte (liquid 2) to the outside via external liquid 2 inlets / outlets 970a~b on manifold elements 901 and 902, respectively, as described in Section 2 above.

[0327] Optionally, the array 900 is configured to use gases and liquids under pressure. Optionally, each pressure vessel 910 incorporates a pressurized annular liquid or annular gas between the outer wall of the cell stack and the inner wall of the pressure vessel, as described in Section 1(i) above. Optionally, oxygen and hydrogen gases pass through a gas equalization system of the type shown in Section 1(ii)(a)-(b) above, via inlets / outlets 940a-b and 950a-b, respectively. Optionally, the oxygen and hydrogen gas pressures in the cell stacks within the pressure vessels 910 are controlled via coarse and fine control valves incorporated at the outer ends of the oxygen and hydrogen gas lines, respectively, as described in Section 1(iii) above. Optionally, the cell stacks within the pressure vessels 910 within the array 900 are cooled as described in Section 3 above. Optionally, the state of each cell in the cell stacks within the pressure vessels 910 within the array 900 is monitored and controlled as described in Section 4 above.

[0328] The embodiments further relate to manifold elements suitable for manifolding cell stacks into arrays. Preferably, the manifold elements may consist of polymer materials, fiber or filler-reinforced polymer materials, composite materials, metals, metal alloys, or other materials. Preferably, the manifold elements can be manufactured by machining, 3D printing, molding including but not limited to injection molding, or other manufacturing techniques.

[0329] While the manifold elements 901 and 902 in Figure 14 are shown as single structures, each connecting to five cell stacks within five pressure vessels 910, it should be understood that there are techniques for pre-assembling such manifold elements from five or more separate manifold sub-elements, some of which can connect to only a single cell stack. For example, the technique taught in U.S. Patent No. 5,405,528 describes the assembly of manifold elements for a filter system by combining multiple identical manifold sub-elements, referred to in U.S. Patent No. 5,405,528 as “symmetric headers.”

[0330] Manifold elements 901 and 902 can similarly be manufactured by assembling the manifold sub-element 1000 shown in Figure 15. A cross-section 1000a of the manifold sub-element 1000 is also shown. The manifold sub-element 1000 may incorporate, for example, internal pipe 1001 (for hydrogen gas to enter and exit the attached stack), internal pipe 1002 (for hydrogen gas to enter and exit the attached stack via a second path within the attached stack), internal pipe 1003 (for oxygen gas to enter and exit the attached stack), internal pipe 1004 (for oxygen gas to enter and exit the attached stack via a second path within the attached stack), internal pipe 1005 (for the flow of liquid 1 into and out of the attached stack), and internal pipe 1006 (for the flow of liquid 2 into and out of the attached stack). The internal tubes 1001-1006, i.e., inlets / outlets, are positioned within or on the manifold sub-elements 1000 so that when the multiple manifold sub-elements 1000 are compressed laterally and horizontally to assemble the manifold element 901 or 902, the individual internal tubes 1001-1006 align into individual tubes as a single whole, and each individual flow path of the attached cell stack is accumulated.

[0331] Furthermore, while Figure 14 shows an example where manifold elements 901 and 902 are connected to and in contact with five cell stacks and associated pressure vessels 910, it should be understood that manifold elements can be connected to any number of cell stacks. Many arrangements of cell stacks and manifold elements are possible, all of which fall within the scope and definition of the array.

[0332] Furthermore, the cell stacks do not have to be manifolded only in the horizontal plane, as shown in Array 900 in Figure 14. Alternatively, they may be manifolded in the vertical plane, or they may be manifolded in both the horizontal and vertical planes. Many rearrangements of the cell stacks and manifold elements are possible, all of which fall within the scope and definition of the array.

[0333] The above types of arrays can be further combined into a "3D array," which is a collection of arrays, where each array is not connected to the next array by a shared common manifold element, but still shares common piping and / or wiring and / or a common management / control system and / or a common decentralized balance of plant components (e.g., water supply / removal systems, cooling systems, etc., but not limited to these).

[0334] Drain receiver design for vertically arranged cell stacks When multiple cell stacks 910 are arranged vertically to one another, a single vertical pipe (within the manifold element) that collects and discharges the “liquid outflow” from each cell stack may require several design considerations. This type of vertical drain pipe is referred to herein as a “drain receptacle.” Such drain receptacles generally rely on gravity for downward liquid flow. However, it may be important to design the drain receptacle so as to separate the downward-flowing (vertical) liquid column from the stationary body of gas present within it.

[0335] Therefore, the diameter of the drain receiver may generally need to be particularly larger than the diameter of the horizontal pipe supplying the liquid to the drain receiver. This may be necessary to prevent the formation of gas or liquid locks in the drain receiver. For example, if the vertical pipe 650 in Figure 11 functions as a drain receiver receiving liquid discharges from multiple pipes 650a from multiple cells or cell stacks 210 arranged vertically above and below each other, the diameter of pipe 650 may need to be particularly larger than the diameter of pipes 650a. The inner pipe wall of the vertical drain receiver 650 may need to include a helical flow channel structure to keep the flowing liquid separated from static gas. Such a helical structure may be used to facilitate the flow of liquid through the drain receiver along the pipe wall, allowing gas to occupy the center of the pipe.

[0336] The gas pressure in the drain receptacle may be controlled by the ejector 660. The ejector 660 may need to be able to shut down if the liquid level in tube 650 becomes too high and could enter the ejector 660. The pressure in the tube can be altered by changing the gas bleed through orifice 796 (Figure 12) in tube 650a. For example, instead of using a fixed orifice, a valve (i.e., an "active" orifice) whose aperture can be changed can be used at orifice 796. Several other design considerations may need to be taken into account.

[0337] (6) Load following or grid balancing "Load following" refers to the phenomenon in which electrosynthesis, electrical energy cells, or cell stacks consume electricity from renewable energy sources. This energy output changes over time and requires a constant change in the speed of their electrical operation. In other words, the energy consumption rate ("load") of electrosynthesis, electrical energy cells, or cell stacks follows changes in the energy output of renewable energy sources, which, for example, changes according to the brightness of sunlight in the case of a solar power generator, or according to the wind speed in the case of a wind power generator.

[0338] "Grid balancing" refers to the phenomenon in which electrical energy cells or cell stacks transmit a constantly changing level of power, thereby maintaining the total energy available on a power grid that receives power from renewable energy sources whose energy output changes over time. In other words, the rate of electrocombination or energy transmission by electrical energy cells or cell stacks to maintain the total energy available on the grid at any given time must constantly change to "balance" the fluctuations in power supplied to the grid by the associated renewable energy sources.

[0339] In various exemplary embodiments, the embodiments relate to a balance of plant for electrosynthesis or electroenergy liquid gas cells or cell stacks having a novel and / or improved ability to "load-follow" a renewable energy source or a "grid-balancing" electrical grid supplied by a renewable energy source, or a method of operation.

[0340] In one example, load following or grid balancing is achieved by systematically disconnecting power connections to put the system into standby mode, or by engaging power connections to remove individual stacks or sets of stacks within an array of electrosynthetic liquid gas cell stacks from standby mode.

[0341] In another example, load following or grid balancing is performed by systematically disconnecting power connections to put the system into standby mode, or by engaging power connections to remove individual arrays or sets of arrays within a 3D array of electrosynthetic liquid gas cell stacks from standby mode.

[0342] In further examples, electrosynthetic or electroenergy liquid gas cell stacks used for load following or grid balancing are those of water electrolyzers and / or hydrogen-oxygen fuel cells. Optionally, the cell stack and associated balance of plant may operate as either a water electrolyzer or a hydrogen-oxygen fuel cell, i.e., a regenerative fuel cell-electrolyzer.

[0343] Electrosynthesis and electrical energy liquid gas cells or cell stacks The electrosynthetic liquid gas cell or cell stack described above may preferably be (i) a water electrolytic cell, (ii) a chlor-alkali electrolytic cell, (iii) a cell for ammonia production, or (iv) a CO2 electrolytic cell including a composite carbon capture and CO2 electrolytic cell, or (v) any other type of liquid gas cell or cell stack that can be considered an electrosynthetic cell or cell stack. Optionally, the electrosynthetic liquid gas cell or cell stack described above may include combinations of the cell types described above.

[0344] The above-described electrical energy liquid gas cell or cell stack may preferably be (i) a hydrogen-oxygen fuel cell including a polymer electrolyte membrane (PEM) fuel cell or an alkaline fuel cell, (ii) a direct alcohol fuel cell including but not limited to a direct methanol fuel cell or a direct ethanol fuel cell, (iii) a phosphoric acid fuel cell, (iv) an ammonia fuel cell, or (v) any other type of liquid gas cell or cell stack that can be considered an electrical energy cell or cell stack. Optionally, the above-described electrical energy liquid gas cell or cell stack may include combinations of the above-described cell types.

[0345] combination of features According to various non-limiting exemplary embodiments, the following points disclose combinations of features that provide various exemplary systems and / or exemplary operating methods:

[0346] 1.1a. A gas pressure equalization system for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a primary gas in bulk form within the cell or cell stack.

[0347] 1.1b. A gas pressure equalization system for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a bulk form of a first gas from a bulk form of a second gas within the cell or cell stack.

[0348] 1.2a. A gas pressure equalization control system or method for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a primary gas in bulk form within the cell or cell stack.

[0349] 1.2b. A gas pressure equalization control system or method for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a first gas in bulk form from a second gas in bulk form within the cell or cell stack.

[0350] 1.3a. A gas circulation or recirculation system or method for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a primary gas in bulk form within the cell or cell stack.

[0351] 1.3b. A gas circulation or recirculation system or method for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a primary gas in bulk form from a secondary gas in bulk form within the cell or cell stack.

[0352] 1.4a. A liquid management system or method for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a primary gas in bulk form within the cell or cell stack.

[0353] 1.4b. A liquid management system or method for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a primary gas in bulk form from a secondary gas in bulk form within the cell or cell stack.

[0354] 1.5a. A cooling management system or method for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a primary gas in bulk form within the cell or cell stack.

[0355] 1.5b. A cooling management system or method for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a bulk form of a first gas from a bulk form of a second gas within the cell or cell stack.

[0356] 1.6. A monitoring or management system or method for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the monitoring or management system or method uses a computer chip or one or more computer chips within one or more individual cells in a cell or cell stack.

[0357] 1.7a. An electrosynthesis or electroenergy liquid gas cell or cell stack configuration, wherein the cell stack is configured to separate and retain a primary gas in bulk form within the cell stack.

[0358] 1.7b. An electrosynthesis or electroenergy liquid gas cell or cell stack configuration, wherein the cell stack is configured to separate and hold a bulk form of a first gas from a bulk form of a second gas within the cell stack.

[0359] 1.8a. A gas pressure equalization system for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and retain a primary gas in bulk form within the cell or cell stack, and the gas pressure equalization system is A first pressure equalizing tank for at least partially containing a first liquid having a first liquid level and partially containing a first gas in bulk form, wherein the first gas is located above the first liquid level, and A first gas conduit for transferring bulk gas between a cell or cell stack and a first pressure equalization tank. A gas pressure equalization system equipped with this system.

[0360] 1.8b. A gas pressure equalization system for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to separate and hold a bulk form of a first gas from a bulk form of a second gas within the cell or cell stack, and the gas pressure equalization system is A first pressure equalizing tank for at least partially containing a first liquid having a first liquid level and partially containing a first gas in bulk form, wherein the first gas is located above the first liquid level, and A first gas conduit for transferring bulk gas between a cell or cell stack and a first pressure equalization tank. A gas pressure equalization system equipped with this system.

[0361] 1.9a. A method for operating a gas pressure equalization system for electrosynthesis or electroenergy liquid gas cells or cell stacks, A step of operating a cell or cell stack to generate or consume a first gas, wherein the cell or cell stack is configured to keep the first gas in bulk form isolated within the cell or cell stack, and A step of discharging or flowing a first gas in bulk form into a first pressure equalizing tank via a first gas conduit, wherein the first pressure equalizing tank at least partially contains a first liquid having a first liquid level, and the first gas is positioned above the first liquid level. Methods that include...

[0362] 1.9b. A method for operating a gas pressure equalization system for electrosynthesis or electroenergy liquid gas cells or cell stacks, A step of operating a cell or cell stack to generate or consume a first gas and a second gas, wherein the cell or cell stack is configured to keep the first gas in bulk form separated from the second gas in bulk form within the cell or cell stack, and A step of discharging or flowing a first gas in bulk form into a first pressure equalizing tank via a first gas conduit, wherein the first pressure equalizing tank at least partially contains a first liquid having a first liquid level, and the first gas is positioned above the first liquid level. Methods that include...

[0363] 2. The first pressure equalization tank is located below any one or more of the preceding items, either a cell or a cell stack.

[0364] 3. The cell or cell stack is configured such that the bulk form of the first gas remains separated from the bulk form of the second gas within the cell or cell stack, and further, A second pressure equalizing tank for at least partially containing a second liquid having a second liquid level and partially containing a second gas in bulk form, wherein the second gas is located above the second liquid level, and Second gas conduit for transferring bulk form of the second gas between the cell or cell stack and the second pressure equalization tank. Any one or more of the preceding items, including further.

[0365] 4. One or more of the preceding items in which the second liquid is the same as the first liquid.

[0366] 5. The first and second pressure equalization tanks are located below the cell or cell stack, and are one or more of the preceding items.

[0367] 6. Connecting pipe for transferring the first or second liquid between the first pressure equalization tank and the second pressure equalization tank. Any one or more of the preceding items, including further.

[0368] 7. One or more of the preceding items, wherein the connecting pipe is positioned below the first liquid level and the second liquid level.

[0369] 8. The connecting pipes are located at or near the bottom of the first pressure equalization tank and at or near the bottom of the second pressure equalization tank, one or more of the preceding items.

[0370] 9. One or more of the preceding items in which the connecting tube is completely filled with liquid during operation.

[0371] 10. The first gas is partially held in the first headspace above the first liquid level of the first liquid in the first pressure equalization tank, one or more of the preceding items.

[0372] 11. One or more of the preceding items, wherein the first gas conduit is located above the first liquid level.

[0373] 12. One or more of the preceding items in which the first gas conduit is located in the first headspace.

[0374] 13. One or more of the preceding items, wherein the first gas pipeline is located above the first pressure equalization tank.

[0375] 14. Further including a first outlet / inlet gas port for transferring the first gas to or from the first pressure equalization tank, the first outlet / inlet gas port being located above the first liquid level, one or more of the preceding items.

[0376] 15. Any one or more of the preceding items, further including a first valve connected to the first outlet / inlet gas port.

[0377] 16. The second gas is partially held in the second headspace above the second liquid level of the second liquid in the second pressure equalization tank, one or more of the preceding items.

[0378] 17. One or more of the preceding items, wherein the second gas conduit is located above the second liquid level.

[0379] 18. One or more of the preceding items in which the second gas conduit is located in the second headspace.

[0380] 19. One or more of the preceding items, wherein the second gas pipeline is located above the second pressure equalization tank.

[0381] 20. Further including a second outlet / inlet gas port for transferring a second gas to or from the second pressure equalization tank, the second outlet / inlet gas port being located above the second liquid level, one or more of the preceding items.

[0382] 21. Any one or more of the preceding items, further including a second valve connected to the second outlet / inlet gas port.

[0383] 22. One or more preceding items configured to generate or consume a first gas or a second gas in a cell or cell stack.

[0384] 23. The first pressure equalization tank is partially filled with the first liquid, one or more of the preceding items.

[0385] 24. The second pressure equalization tank is partially filled with the second liquid, one or more of the preceding items.

[0386] 25. One or more of the preceding items, further including one or more programmable logic controllers for operating the first valve.

[0387] 26. One or more preceding items in which a pressure vessel surrounds a cell or cell stack.

[0388] 27. One or more of the preceding items in which the pressure vessel contains annular gas.

[0389] 28. Annular gas passing through the space between a cell or cell stack and one or more walls of a pressure vessel, one or more of the preceding items.

[0390] 29. Annular gas exits a pressure vessel, and the exiting annular gas is monitored for the presence of one or more of the preceding items for the detection of the presence of one or more contaminating gases.

[0391] 30. One or more of the preceding items in which a pressure vessel contains an annular liquid.

[0392] 31. One or more of the preceding items, wherein the liquid outlet pipe of a cell or cell stack is connected to a liquid circulation tank, and liquid is drawn out of the cell or cell stack through the liquid outlet pipe by an ejector or pump.

[0393] 32. The liquid drawn from the cell or cell stack is either a liquid electrolyte or a coolant, one or more of the preceding items.

[0394] 33. One or more of the preceding items, which are pumped or ejected from a liquid circulation tank into a cell or cell stack via one or more pipes.

[0395] 34. The liquid circulation tank is located below the cell or cell stack, one or more of the preceding items.

[0396] 35. The liquid circulation tank includes one or more of the preceding items, including the gas headspace.

[0397] 36. A step of operating a cell or cell stack to generate or consume a first gas and a second gas, wherein the cell or cell stack is configured to keep the first gas in bulk form separated from the second gas in bulk form within the cell or cell stack, and One or more of the preceding items, comprising the step of discharging or inflowing a first gas in bulk form into a first pressure equalizing tank via a first gas conduit, wherein the first pressure equalizing tank at least partially contains a first liquid having a first liquid level, and the first gas is positioned above the first liquid level.

[0398] 37. The first liquid is one or more of the preceding items, having a substantially constant density during operation.

[0399] 38. The first liquid is one or more of the preceding items that do not contain bubbles during operation.

[0400] 39. The first liquid is one or more of the preceding items that do not enter the cell or cell stack during operation.

[0401] 40. One or more of the preceding items in which the first liquid is the same as the liquid electrolyte of the electrochemical reaction occurring within the cell or cell stack.

[0402] 41. The pressure of the first liquid in the first pressure equalization tank is substantially equalized with the pressure of the liquid electrolyte in the cell or cell stack, one or more of the preceding items.

[0403] 42. The first pressure equalization tank is located below any one or more of the preceding items, either a cell or a cell stack.

[0404] 43. Any one or more of the preceding items, further comprising the step of adjusting the pressure of the first gas in the first pressure equalization tank in order to maintain the first liquid level at a certain height.

[0405] 44. A step of discharging or flowing a second gas in bulk form into a second pressure equalizing tank via a second gas conduit, wherein the second pressure equalizing tank at least partially contains a second liquid having a second liquid level, and the second gas is positioned above the second liquid level. Any one or more of the preceding items, including further.

[0406] 45. One or more of the preceding items in which the second liquid is the same as the first liquid.

[0407] 46. ​​A second pressure equalization tank is located below any one or more of the preceding items, either a cell or a cell stack.

[0408] 47. A connecting pipe is installed between the first pressure equalization tank and the second pressure equalization tank. Steps in which the first or second liquid flows between the first and second pressure equalizing tanks via a connecting pipe when the pressure of the first gas in the first pressure equalizing tank is different from the pressure of the second gas in the second pressure equalizing tank. Any one or more of the preceding items, including further.

[0409] 48. One or more of the preceding items in which the connecting pipe is positioned below the first liquid level and the second liquid level during operation.

[0410] 49. A step of operating an electrosynthesis or electroenergy liquid gas cell or cell stack to produce or consume a first gas or a second gas, wherein the first gas and the second gas are each in bulk form; If the pressure of the first gas exceeds the pressure of the second gas, The first step is to discharge the first liquid from the first pressure equalization tank and flow it into the second pressure equalization tank via a connecting pipe. A step of lowering the first liquid level in the first pressure equalization tank, thereby lowering the pressure of the first gas, The steps include raising the second liquid level in the second pressure equalization tank, thereby increasing the pressure of the second gas, and After the flow of the first liquid stops, the first liquid is allowed to flow again until the pressure of the first gas equals the pressure of the second gas. Any one or more of the preceding items, including further.

[0411] 50. A step of operating an electrosynthesis or electroenergy liquid gas cell or cell stack to produce or consume a first gas or a second gas, wherein the first gas and the second gas are each in bulk form; If the pressure of the second gas exceeds the pressure of the first gas, The step of discharging the second liquid from the second pressure equalization tank and flowing it into the first pressure equalization tank via a connecting pipe, A step of lowering the second liquid level in the second pressure equalization tank, thereby lowering the pressure of the second gas, A step of raising the first liquid level in the first pressure equalization tank, thereby increasing the pressure of the first gas, and, After the flow of the second liquid stops, the second liquid is allowed to flow until the pressure of the second gas equals the pressure of the first gas. Any one or more of the preceding items, including further.

[0412] 51. The first or second liquid is one or more of the preceding items, which spontaneously flow in response to any pressure difference between the pressure of the first gas in the first pressure equalization tank and the pressure of the second gas in the second pressure equalization tank.

[0413] 52. Any one or more of the preceding items, further comprising the steps of adjusting the pressure of a first gas in a first pressure equalizing tank and / or adjusting the pressure of a second gas in a second pressure equalizing tank, so as to maintain the first and second liquid levels at the same height.

[0414] 53. Any one or more of the preceding items, further comprising a first outlet / inlet gas port for transferring a first gas to or from a first pressure equalization tank, the first outlet / inlet gas port being positioned above the first liquid level, and further comprising a first valve connected to the first outlet / inlet gas port, the first valve being operated to adjust the pressure of the first gas in the first pressure equalization tank and change the height of the first liquid level.

[0415] 54. Any one or more of the preceding items, further including using one or more programmable logic controllers to automatically operate the first valve.

[0416] 55. Any one or more of the preceding items, further including a second outlet / inlet gas port for transferring a second gas to or from the second pressure equalization tank, the second outlet / inlet gas port being located above the second liquid level, and further including a second valve connected to the second outlet / inlet gas port, the second valve being operated to adjust the pressure of the second gas in the second pressure equalization tank and change the height of the second liquid level.

[0417] 56. Any one or more of the preceding items, further including using one or more programmable logic controllers to automatically operate a second valve.

[0418] 57. Any one or more of the preceding items, further including one or more programmable logic controllers that monitor the height of a first liquid level and / or a second liquid level using one or more sensors.

[0419] 58. Any one or more of the preceding items, further comprising the step of maintaining the pressure of the first gas and the pressure of the second gas at a constant differential pressure by maintaining the first liquid level and the second liquid level at a constant height difference.

[0420] 59. The first gas is sparingly soluble in the first liquid, one or more of the preceding items.

[0421] 60. The volume of the first liquid in the first pressure equalization tank is greater than the volume of the first gas in the cell or cell stack, and the first headspace of the first pressure equalization tank and the first gas conduit, one or more of the preceding items.

[0422] 61. The volume of the second liquid in the second pressure equalization tank is greater than the volume of the second gas in the cell or cell stack, and the second headspace of the second pressure equalization tank and the second gas conduit, one or more of the preceding items.

[0423] 62. Any one or more of the preceding items, wherein the cell or cell stack is an electrosynthetic liquid gas water electrolytic cell, the first gas is oxygen, and the second gas is hydrogen.

[0424] Throughout this specification and the appended claims, unless otherwise required by context, the word “comprise” and variations such as “comprises” or “comprising” are understood to mean that they include the integers or steps or groups of integers or steps described, but not any other integers or steps or groups of integers or steps.

[0425] Any optional embodiment may also be said to be broadly comprised of any or all combinations of two or more of the parts, elements, and features mentioned or indicated individually or collectively herein, and any particular integer having known equivalents in the art to which the invention relates is mentioned herein and such known equivalents are deemed to be incorporated herein as if they were described separately.

[0426] While preferred embodiments have been described in detail, it should be understood that many modifications, changes, substitutions, or alterations will be apparent to those skilled in the art without departing from the scope of the present invention.

Claims

1. A gas pressure equalization system for an electrosynthesis or electroenergy liquid gas cell or cell stack, wherein the cell or cell stack is configured to keep a primary gas in bulk form separated within the cell or cell stack, and the gas pressure equalization system is A first pressure equalizing tank for at least partially containing a first liquid having a first liquid level and for partially containing the first gas in bulk form, wherein the first gas is positioned above the first liquid level, and A first gas conduit for transferring the first gas in bulk form between the cell or cell stack and the first pressure equalization tank. A gas pressure equalization system equipped with this system.

2. The gas pressure equalization system according to claim 1, wherein the first pressure equalization tank is located below the cell or cell stack.

3. The cell or cell stack is configured such that the bulk form of the first gas remains separated from the bulk form of the second gas within the cell or cell stack. A second pressure equalizing tank for at least partially containing a second liquid having a second liquid level and for partially containing the second gas in bulk form, wherein the second gas is located above the second liquid level, and A second gas conduit for transferring the second gas in bulk form between the cell or cell stack and the second pressure equalization tank. The gas pressure equalization system according to claim 1 or 2, further comprising:

4. The gas pressure equalization system according to claim 3, wherein the second liquid is the same as the first liquid.

5. The gas pressure equalization system according to claim 3 or 4, wherein the first pressure equalization tank and the second pressure equalization tank are located below the cell or cell stack.

6. A connecting pipe for transferring the first liquid or the second liquid between the first pressure equalization tank and the second pressure equalization tank. The gas pressure equalization system according to claim 4 or 5, further comprising:

7. The gas pressure equalization system according to claim 6, wherein the connecting pipe is positioned below the first liquid level and the second liquid level.

8. The gas pressure equalization system according to claim 6 or 7, wherein the connecting pipe is located at or near the bottom of the first pressure equalization tank and at or near the bottom of the second pressure equalization tank.

9. The gas pressure equalization system according to any one of claims 6 to 8, wherein the connecting pipe is completely filled with liquid during operation.

10. The gas pressure equalization system according to any one of claims 1 to 9, wherein the first gas is partially held in a first headspace above the first liquid level of the first liquid in the first pressure equalization tank.

11. The gas pressure equalization system according to any one of claims 1 to 10, wherein the first gas conduit is positioned above the first liquid level.

12. The gas pressure equalization system according to claim 10, wherein the first gas conduit is located in the first headspace.

13. The gas pressure equalization system according to any one of claims 1 to 12, wherein the first gas conduit is located at the top of the first pressure equalization tank.

14. The gas pressure equalization system according to any one of claims 1 to 13, further comprising a first outlet / inlet gas port for transferring the first gas to or from the first pressure equalization tank, wherein the first outlet / inlet gas port is positioned above the first liquid level.

15. The gas pressure equalization system according to claim 14, further comprising a first valve connected to the first outlet / inlet gas port.

16. The gas pressure equalization system according to any one of claims 3 to 9, wherein the second gas is partially held in a second headspace above the second liquid level of the second liquid in the second pressure equalization tank.

17. The gas pressure equalization system according to claim 16, wherein the second gas conduit is positioned above the second liquid level.

18. The gas pressure equalization system according to claim 16 or 17, wherein the second gas conduit is located in the second headspace.

19. The gas pressure equalization system according to any one of claims 16 to 18, wherein the second gas conduit is located at the top of the second pressure equalization tank.

20. The gas pressure equalization system according to any one of claims 16 to 19, further comprising a second outlet / inlet gas port for transferring the second gas to or from the second pressure equalization tank, wherein the second outlet / inlet gas port is positioned above the second liquid level.

21. The gas pressure equalization system according to claim 20, further comprising a second valve connected to the second outlet / inlet gas port.

22. The gas pressure equalization system according to any one of claims 1 to 21, wherein the cell or cell stack is configured to generate or consume the first gas.

23. The gas pressure equalization system according to any one of claims 1 to 22, wherein the first pressure equalization tank is partially filled with the first liquid.

24. The gas pressure equalization system according to any one of claims 3 to 9, wherein the second pressure equalization tank is partially filled with the second liquid.

25. The gas pressure equalization system according to claim 15, further comprising one or more programmable logic controllers for operating the first valve.

26. The gas pressure equalization system according to any one of claims 1 to 25, wherein the pressure vessel surrounds the cell or cell stack.

27. The gas pressure equalization system according to claim 26, wherein the pressure vessel contains an annular gas.

28. The gas pressure equalization system according to claim 27, wherein the annular gas passes through the space between the cell or cell stack and one or more walls of the pressure vessel.

29. The gas pressure equalization system according to claim 27 or 28, wherein the annular gas exits the pressure vessel, and the exiting annular gas is monitored to detect the presence of one or more contaminating gases.

30. The gas pressure equalization system according to claim 26, wherein the pressure vessel contains an annular liquid.

31. The gas pressure equalization system according to any one of claims 1 to 30, wherein the liquid outlet pipe of the cell or cell stack is connected to a liquid circulation tank, and liquid is drawn out of the cell or cell stack via the liquid outlet pipe by an ejector or pump.

32. The gas pressure equalization system according to claim 31, wherein the liquid drawn from the cell or cell stack is a liquid electrolyte or a coolant.

33. The gas pressure equalization system according to claim 31 or 32, wherein the liquid is pumped from the liquid circulation tank into the cell or cell stack via one or more pipes by a pump or ejector.

34. The gas pressure equalization system according to any one of claims 31 to 33, wherein the liquid circulation tank is located below the cell or cell stack.

35. The gas pressure equalization system according to any one of claims 31 to 34, wherein the liquid circulation tank includes a gas head space.

36. A method for operating a gas pressure equalization system for electrosynthesis or electroenergy liquid gas cells or cell stacks, A step of operating the cell or cell stack to generate or consume a first gas, wherein the cell or cell stack is configured to keep the first gas in bulk form isolated within the cell or cell stack, and A step of discharging or flowing the first gas in bulk form into a first pressure equalizing tank via a first gas conduit, wherein the first pressure equalizing tank contains at least partially a first liquid having a first liquid level, and the first gas is positioned above the first liquid level. Methods that include...

37. The method according to claim 36, wherein the first liquid has a substantially constant density during operation.

38. The method according to claim 36 or 37, wherein the first liquid does not contain bubbles during operation.

39. The method according to any one of claims 36 to 38, wherein the first liquid does not enter the cell or cell stack during operation.

40. The method according to any one of claims 36 to 39, wherein the first liquid is the same as the liquid electrolyte of the electrochemical reaction occurring in the cell or cell stack.

41. The method according to claim 40, wherein the pressure of the first liquid in the first pressure equalization tank is substantially equalized with the pressure of the liquid electrolyte in the cell or cell stack.

42. The method according to any one of claims 36 to 41, wherein the first pressure equalization tank is located below the cell or cell stack.

43. The method according to any one of claims 36 to 42, further comprising the step of adjusting the pressure of the first gas in the first pressure equalization tank in order to maintain the first liquid level at a certain height.

44. The cell or cell stack is configured such that the bulk form of the first gas remains separated from the bulk form of the second gas within the cell or cell stack. A step of discharging or flowing the second gas in bulk form into a second pressure equalizing tank via a second gas conduit, wherein the second pressure equalizing tank at least partially contains a second liquid having a second liquid level, and the second gas is positioned above the second liquid level. The method according to any one of claims 36 to 43, further comprising:

45. The method according to claim 44, wherein the second liquid is the same as the first liquid.

46. The method according to claim 44 or 45, wherein the second pressure equalization tank is located below the cell or cell stack.

47. A connecting pipe is installed between the first pressure equalization tank and the second pressure equalization tank. The first liquid or the second liquid flows between the first and second pressure equalizing tanks via the connecting pipe when the pressure of the first gas in the first pressure equalizing tank is different from the pressure of the second gas in the second pressure equalizing tank. The method according to any one of claims 44 to 46, further comprising:

48. The method according to claim 47, wherein the connecting pipe is positioned below the first liquid level and the second liquid level during operation.

49. A step of operating the electrosynthesis or electroenergy liquid gas cell or cell stack to generate or consume the first gas or the second gas, wherein the first gas and the second gas are each in bulk form, and If the pressure of the first gas exceeds the pressure of the second gas, The steps of discharging the first liquid from the first pressure equalization tank and allowing it to flow into the second pressure equalization tank via the connecting pipe, A step of lowering the first liquid level in the first pressure equalization tank, thereby lowering the pressure of the first gas, The steps of raising the second liquid level in the second pressure equalization tank, thereby increasing the pressure of the second gas, and After the first liquid stops flowing, the first liquid is allowed to flow again until the pressure of the first gas and the pressure of the second gas become equal. A method for operating the gas pressure equalization system according to any one of claims 6 to 9, including the method described in any one of claims 6 to 9.

50. A step of operating the electrosynthesis or electroenergy liquid gas cell or cell stack to generate or consume the first gas or the second gas, wherein the first gas and the second gas are each in bulk form, and If the pressure of the second gas exceeds the pressure of the first gas, The steps of discharging the second liquid from the second pressure equalization tank and allowing it to flow into the first pressure equalization tank via the connecting pipe, A step of lowering the second liquid level in the second pressure equalization tank, thereby lowering the pressure of the second gas, The steps of raising the first liquid level in the first pressure equalization tank, thereby increasing the pressure of the first gas, and After the flow of the second liquid stops, the second liquid is allowed to flow until the pressure of the second gas becomes equal to the pressure of the first gas. A method for operating the gas pressure equalization system according to any one of claims 6 to 9, including the method described in any one of claims 6 to 9.

51. The method according to claim 49 or 50, wherein the first liquid or the second liquid flows spontaneously in response to the pressure difference between the pressure of the first gas in the first pressure equalization tank and the pressure of the second gas in the second pressure equalization tank.

52. The method according to any one of claims 49 to 51, further comprising the steps of adjusting the pressure of the first gas in the first pressure equalizing tank so as to maintain the first liquid level and the second liquid level at the same height, and / or adjusting the pressure of the second gas in the second pressure equalizing tank.

53. The method according to any one of claims 36 to 52, further comprising a first outlet / inlet gas port for transferring the first gas to or from the first pressure equalization tank, the first outlet / inlet gas port further comprising a first valve positioned above the first liquid level and connected to the first outlet / inlet gas port, the first valve being operated to adjust the pressure of the first gas in the first pressure equalization tank and change the height of the first liquid level.

54. The method according to claim 53, further comprising using one or more programmable logic controllers to automatically operate the first valve.

55. The method according to any one of claims 49 to 54, further comprising a second outlet / inlet gas port for transferring the second gas to or from the second pressure equalization tank, the second outlet / inlet gas port further comprising a second valve located above the second liquid level and connected to the second outlet / inlet gas port, the second valve being operated to adjust the pressure of the second gas in the second pressure equalization tank and change the height of the second liquid level.

56. The method according to claim 55, further comprising using one or more programmable logic controllers to automatically operate the second valve.

57. The method according to claim 54 or 56, further comprising the step of the one or more programmable logic controllers monitoring the height of the first liquid level and / or the height of the second liquid level using one or more sensors.

58. The method according to any one of claims 49 to 51, further comprising the step of maintaining the pressure of the first gas and the pressure of the second gas at a constant differential pressure by maintaining the first liquid level and the second liquid level at a constant height difference.

59. The method according to any one of claims 36 to 58, wherein the first gas is sparingly soluble in the first liquid.

60. The method according to any one of claims 36 to 59, wherein the volume of the first liquid in the first pressure equalization tank is greater than the volume of the first gas in the cell or cell stack, and the first headspace of the first pressure equalization tank and the first gas conduit.

61. The method according to any one of claims 49 to 60, wherein the volume of the second liquid in the second pressure equalization tank is greater than the volume of the second gas in the cell or cell stack, and the second headspace of the second pressure equalization tank and the second gas conduit.

62. The method according to any one of claims 44 to 52, wherein the cell or cell stack is an electrosynthetic liquid gas water electrolysis cell, the first gas is oxygen, and the second gas is hydrogen.

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