Reactor and electrolyzer apparatus with controllable gravitational flow of electrolyte fluid between stacked reactors

Abstract

An electrolyzer includes a plurality of vertically stacked electrolysis cells, with one or more electrolyte supply tubes adjacent to said plurality of electrolysis cells and having a plurality of fluid outlets configured to discharge an electrolyte solution from said one or more electrolyte supply tubes to each of said plurality of electrolysis cells. Each of the cells is provided with one or more drain assemblies, each drain assembly comprising a drain basin equipped, with a drain valve, such that some or all drain valves in a given set of assemblies are engaged by a. common control member configured and operable to actuate each of the drain valves between a closed and an open position. A plurality of electrodes is connectable to one or more electrical power sources and configured to pass electric current through the electrolyte solution introduced into said electrolysis cells via said outlets.

Description

[0001] REACTOR AND ELECTROLYZER APPARATUS WITH CONTROLLABLE GRAVITATIONAL FLOW OF ELECTROLYTE FLUID BETWEEN STACKED REACTORS

[0002] RELATED APPLICATIONS

[0003] This Application claims priority to U.S. Provisional Patent Application No. 63 / 658,137, filed June 10, 2024, entitled “Reactor and Electrolyzer Apparatus,” the contents of which are hereby incorporated by reference as if fully set forth herein.

[0004] TECHNOLOGICAL FIELD

[0005] The invention generally contemplates a reactor and systems implementing same, and more specifically, but not exclusively, to an apparatus featuring vertically stacked reactors, wherein an electrolyte solution does not flow between the electrolysis cells in the stacks during filling and discharging, and the stacks are separated by a gas layer during electrolysis, thereby preventing shunt currents.

[0006] BACKGROUND OF THE INVENTION

[0007] Electrolyzers are electrochemical devices that are used to separate water into hydrogen and oxygen. Construction of an electrolyzer as a cell stack operating in an electrical series arrangement typically requires presence of bipolar elements. As the electrolyte is a good electrical conductor, some of the electrical current applied to the stack may follow a path through the fluid rather than through the electrolytic cells, resulting in a reduction in the electrolyzer’s efficiency. These undesired currents are called “stray currents” or “shunt currents”.

[0008] Various solutions have been proposed for reducing such shunt currents in flowbased systems such as electrolyzers, fuel cells and flow batteries. A bipolar plate that is typically used serves as a common current collector by creating a physical barrier between the cells.

[0009] A way to avoid use of a bipolar plate has been implemented in a system [1] configured such that an electrolyte is allowed to flow uninterruptedly through a bipolar connector that is not a bipolar plate, positioned between any two electrochemical cells, or any two stacks of electrochemical cells, while maintaining a cell activity in terms of totally avoiding or minimizing leakage currents.

[0010] System [2] discloses a different solution for minimizing shunt currents, in which electrolyte flow from one electrochemical cell to a second electrochemical cell is accomplished through generation of drops and flowing of the drops through a perforated plate. The separation of the electrolyte into drops prevents continuous uninterrupted flow of the electrolyte solution, thereby ensuring electrical isolation. When the electrolyte solution is fed through the perforated plate into each cell, a cascaded gravitational flow of drops of the solution is achieved, ensuring gas isolation and minimization or elimination of the shunt currents.

[0011] In addition, known electrolyzer systems often are constructed in a manner that causes released gases to flow through the electrolyte solution. This configuration ultimately hinders the efficiency of the gas production, and may result in undesired mixing of the released hydrogen and oxygen.

[0012] PUBLICATIONS

[0013] [1] International Publication No. WO2022 / 269602.

[0014] [2] International Publication No. W02024 / 257090.

[0015] SUMMARY OF THE INVENTION

[0016] The inventors of the technology disclosed herein have developed a novel gravitational electrolyzer. The electrolyzer is structured of a plurality of vertically stacked (coaxially arranged) electrolysis cells, each independently designed to receive an electrolyte solution through gravitational flow, and to drain simultaneously through gravitational flow.

[0017] Each of the cells is provided with a drain, with the drains of vertically aligned cells being vertically aligned with each other. In some embodiments, the vertically aligned drains are aligned along a common axis and share a common control member. The control member may be a screw or a bolt that extends a distance between the topmost drain (or plate) and the lowest drain (or plate) and is configured to engage each drain in the stack. The control member is preferably configured and operable to actuate each drain in the stack between an open and a closed position, such that when the member is in the closed position the cells contain an amount of the electrolyte solution and when in the open position the cells empty through the drain by gravity. All cells in each stack may be drained simultaneously. As such, at no point during the operation of the electrolyzer is there a continuous uninterrupted flow of the electrolyte solution from cell to cell. Thus, the mechanism of draining avoids entirely a situation in which a shunt current could form.

[0018] In addition, during gas production, each stack is separated from horizontally and vertically adjacent stacks by a gas (either hydrogen or oxygen), which prevents electrical shunt currents from flowing from one stack to an adjacent stack.

[0019] Beyond the prevention of shunt currents, the electrolyzer of the present disclosure has numerous additional advantages. The electrolyzer is operated such that the chemical environment, namely temperature, pressure and gas / fluid ratio, remains uniform in all stacks or cells. The environment is maintained throughput the production process of either gas. Furthermore, the separation of the produced gases is enabled through an external channel, leading to a more effective gas separation, preventing hydrogen and oxygen mixing by gravitational draining of the fluid from the stacks inside the reactors. This configuration also provides a lower thermal mass of the reactor, enabling a possible thermal swing in the electrochemical-thermally activated chemical (E-TAC) operation sequence (e.g., a transition from room temperature operation to heated operation, or vice versa, for shifting between production of hydrogen and oxygen).

[0020] Thus, in a first of its aspects, the invention provides an electrolyzer (or an electrolysis apparatus) comprising:

[0021] -a plurality of horizontally separated stacks in trays that are vertically stacked electrolysis cells (or cells) and one or more electrolyte supply tubes passing through or next to said plurality of electrolysis cells and having a plurality of fluid outlets configured to gravitationally (and separately) discharge an electrolyte solution (or an electrolyte) from said one or more electrolyte supply tubes to each of said plurality of electrolysis cells;

[0022] -one or more drain assemblies arranged as coaxially aligned sets of assemblies; each drain assembly comprises a drain basin equipped with a drain valve, such that some or all drain valves in a given set of assemblies are engaged by a common control member configured and operable to actuate each of the drain valves between a closed and an open position, wherein each drain assembly is associated with at least one cell; and

[0023] -a plurality of electrodes (wherein each cell comprises an electrode assembly of a cathode and an anode) connectable to one or more electrical power sources and configured to pass electric current through the electrolyte solution introduced into said electrolysis cells via said outlets.

[0024] Each layer of electrolysis cells may comprise several stacks in trays, with each cell being in its own isolated electrolyte container. The cells are connected in series or in parallel. All stacks in a given tray and throughout the column of trays may be filled and drained simultaneously.

[0025] In some embodiments, the electrolyzer may comprise one or a plurality of horizontal sections, each containing one or a plurality of electrolysis cells that may be connected in series, wherein, optionally, each section is independently provided with an electrolyte solution, and having a fluid outlet configured to gravitationally discharge the solution from the respective section. In some such examples, the horizontal sections may be arranged in a polygonal configuration, with the drain assemblies being configured within the polygon and the electrolyte supply tubes being configured exterior to the polygon.

[0026] The electrolysis apparatus is typically provided in a housing that is configured to accommodate the plurality of the electrolysis cells that are connected in series. The cells are stacked one on top of the other and, optionally, one beside the other horizontally, and provided with one or more electrolyte supply tubes. The supply tubes may pass through respective one or more bores which are provided in each of the electrolysis cells, or may otherwise be configured adjacent to the electrolysis cells. The supply tubes separately supply each of the cells with the electrolyte solution, through operation of gravity.

[0027] Each of the cells is provided with one or more drain assemblies. Each of the assemblies comprises a drain basin that is fluidically connected with the cell, a drain valve that is normally closed and a control member that is operable to actuate all drain valves in the same set of assemblies from a closed position to an open position.

[0028] Each drain valve comprises a threaded (and movable) valve member.

[0029] Each of the drain assemblies is external to the cells yet fluidically capable of receiving an overflow or an amount of the electrolyte solution and is configured and operable to empty any amount of the electrolyte solution in the cells or its complete volume (namely to completely empty the cells). In some embodiments, all drains within a given set are aligned along a common vertical axis and are fluidically coupled together to define a drainage conduit. This arrangement allows gravitational drainage of the electrolyte solution from some or all cells through one or more common drainage conduit, at once.

[0030] In some cases, each of the cells is configured to receive the electrolyte solution using a pump that forces a flow through one or more common pipes. Each pipe has outlets (i.e. holes) above each electrode tray. The outlets are configured to allow the fluid to flow downward in a similar flow rate into each tray, considering that the pressure in the lower trays is slightly higher than the pressure in the upper trays due to the larger hydrostatic pressure at the lower section of the column during the filling operation.

[0031] The electrolyte solution cannot flow into the cells in any other way.

[0032] Each container holding a stack of electrodes has an opening at a top section that defines a maximum amount or volume of liquid electrolyte each stack is immersed in. Once the container is full or exceeds this maximum amount or volume, the overflow fluid flows gravitationally from said top opening into the common drain conduit towards the bottom of the tray assembly.

[0033] An electrolyzer of the invention may implement one or more electrolysis cells, each configured to receive an electrolyte solution from one or a plurality of supply tubes passing therethrough and may comprise an electrode assembly that is connectable to one or more electrical power sources and configured to pass electric current through the electrolyte solution present in the cell. As the cell arrangement dictates, the electrode assembly (comprising an anode and a cathode) is fully contained within the cell.

[0034] Each of the cells may be shaped as a cup or a vessel and have a size and shape dictated by the dimensions of the apparatus or system or by the volume of electrolyte it is configured to contain.

[0035] In some embodiments, an apparatus of the invention comprises one or more stacked electrolysis cells comprising one or more electrolyte supply tubes, wherein each of the one or more stacked electrolysis cells is a cup-shaped vessel having one or more bores each configured for passage of an electrolyte supply tube therethrough; one or more electrodes connectable to one or more electrical power sources and configured to pass electric current through electrolyte introduced into said electrolysis cell via one or more fluid outlets provided in said electrolyte supply tubes; each of the cells being provided with one or a plurality of assemblies of side drains or a single central drain, as disclosed.

[0036] In some embodiments, an apparatus of the invention comprises one or more stacked electrolysis cells arranged with two or more common electrolyte supply tubes, each positioned at a different location of the cell, wherein each of the one or more stacked electrolysis cells is a cup-shaped vessel having one or more bores each configured for passage of a electrolyte supply tube therethrough; each of the cells being provided with one or a plurality of sets of side drain basins, each basin equipped with a drain valve, such that all drain valves is a given set are coaxially aligned and engaged by a common control member configured and operable to activate each of the drains valves within the set to gravitationally empty the cells from the electrolyte solution.

[0037] The electrolysis apparatus of the invention may be an electrochemical thermally activated chemical cell (E-TAC) or system comprising a plurality of electrochemical cells, as disclosed herein. However, the electrolysis apparatus may also be a conventional (E-E) apparatus in which both charging and discharging of the electrodes is achieved electrically by changing the polarity on the electrodes. In the system, each of the cells may be configured to allow generation of electrolysis products in the form of hydrogen gas and / or oxygen gas in temporally separated steps. Cells and / or systems of the inventions and methods described herein for operating these cells and / or systems permit control of the type of gases that would be produced, i.e., either hydrogen gas or oxygen gas.

[0038] As stated herein, each of the cells is provided with one or a plurality of drains, each drain being equipped with a drain valve, such that all drain valves in a given set are coaxially aligned and engaged by a common control member configured and operable to activate each of the drain valves within the set to gravitationally empty the cells from the electrolyte solution. The drains allow the electrolyte solution to exit the electrolytic cells in a controlled manner without the necessity of a pump. When filled with the electrolyte solution, the cell has a volume of electrolyte having a predetermined depth. The drain basin has a predetermined size to empty the cells at a rate that allows for the rapid cycle of draining and refilling of the cells without interfering with the flow from other cells lower in the vertical stack. The sizing of the drains is dependent on the volume of the electrolytic cell and the number of cells in a stack.

[0039] The drains may be located at a bottom end of each cell or on the cell’s side. The drains are configured to empty most of the electrolyte (given sufficient time) or a substantial portion of the electrolyte volume in the cell in a short, time. Clearly during drainage, some of the electrolyte will remain on the electrodes and inner walls, hence complete fluid drainage is impossible in a finite time or is not required. In some configurations, each cell in the stack has the same number of drains. In each cell, one or more drains may be in the same predetermined location.

[0040] Each set of drains comprises for each cell a drain basin that is equipped with a drain valve. The drain valve may be a. bail valve, gate valve, needle valve, butterfly valve, globe valve, pinch valve, clapper valve or any other valve as known in the art. All drain valves in a given set are coaxially aligned and engaged by a common control member configured and operable to activate each of the drain valves within the set to allow the electrolyte solution within the drain basins to gravitationally empty or flow out. The valve may be actuated by a push-pull action, rotating action or any form of an electromechanical or magnetic actuation.

[0041] The control member may be a threaded member such as a screw or bolt or a rotating shaft and may have a length to engage each drain. In one configuration, the threaded control member is configured to engage a drain valve that is a threaded member. The threaded member has a thread that engages with the control member and thus rotates to allow flow of the solution from the basins. The same threaded member can be configured to open more than one solution basin. The control member may alternatively engage a clapper valve.

[0042] Optionally, the electrolyte supply tubes have outlets sized so as to provide a substantially equal volume of electrolyte fluid to cells at different heights in the stack.

[0043] Optionally, the vertically stacked electrolysis cells are arranged in levels having a polygonal configuration, with the drain assemblies arranged at an interior of the polygon and the electrolyte supply tubes arranged at an exterior of the polygon.

[0044] Optionally, in such embodiments, each electrolyte supply tube may feed more than one, or two or more, or two adjacent, drain assemblies. Optionally, in such embodiments, every' two adjacent electrolysis cells share a drain basin and drain valve.

[0045] Optionally, in such embodiments, the common control member comprises a shaft, wherein each of the drain valves in a given level is arranged on a cylinder, and rotation of the control member causes rotation of the cylinder, thereby opening or closing the valves. Further optionally, the drain valves of all levels are aligned and are arranged on respective cylinders, and the rotation of the control member causes rotation of each of the cylinders simultaneously, thereby opening or closing each of the valves in all levels.

[0046] The invention further provides a method comprising obtaining a system having one or more electrolyte supply tubes configured and operable for filling or supplying electrolyte solution into vertically stacked electrolysis cells of an electrolyzer, wherein said filling is by discharging the electrolyte solution from one or more vertically oriented electrolyte supply tubes that are adjacent to the electrolysis cells into the respective electrolysis cells, and wherein each cell is filled directly from the electrolyte supply tubes without diverting electrolyte solution from cell to cell; activating electrical power sources to thereby pass electric current through the electrolyte solution introduced into said electrolysis cells, thereby producing at least one of hydrogen or oxygen; and following production of at least one of hydrogen or oxygen, simultaneously gravitationally draining the electrolyte solution from the electrolysis cells into a common drain, without diverting electrolyte solution between cells.

[0047] In another implementation, the method includes filling electrolyte solution from one or more electrolyte supply tubes into vertically stacked electrolysis cells of an electrolyzer, wherein said filling is performed by discharging the electrolyte solution from one or more vertically oriented electrolyte supply tubes that are adjacent to the electrolysis cells into the respective electrolysis cells, and wherein each cell is filled directly from the electrolyte supply tubes without diverting electrolyte solution from cell to cell; activating electrical power sources to thereby pass electric current through the electrolyte solution introduced into said electrolysis cells, thereby producing at least one of hydrogen or oxygen; and following production of at least one of hydrogen or oxygen, simultaneously gravitationally draining the electrolyte solution from the electrolysis cells into a common drain, without diverting electrolyte solution between cells.

[0048] In some embodiments, each of the steps is performed on an array of stacks of electrolysis cells, and the method further comprises, during production of the at least one of hydrogen or oxygen, forming a gas barrier of hydrogen or oxygen between horizontally adjacent stacks, to thereby preventing shunt currents from flowing from one stack to an adjacent stack.

[0049] In further embodiments, the method comprising maintaining a ratio of fluid to gas identical in any given stack of the electrolyzer by capturing the gas generated at any given stack of the electrolyzer without passing the generated gas through a different stack of the electrolyzer.

[0050] As discussed, each of the cells is provided with one or more drain assemblies. Each drain assembly includes a drain basin equipped with a drain valve. In some embodiments, some or all drain valves in a given set of assemblies are engaged by a common control member, and the draining step comprises actuating the common control member to thereby transition the drain valves from a closed position to an open position.

[0051] In some embodiments, drains within a given set are aligned along a common vertical axis and are fluidicallv coupled together to define a drainage conduit, and the method comprises draining electrolyte solution from each cell into one or more of the drainage conduits.

[0052] In some embodiments, each drain valve comprises a threaded valve member, and wherein the common control member is a threaded member having a length to engage a threaded valve member of each drain, and wherein the method further comprises rotating the common control member to thereby move the valve member of each drain and open the valves.

[0053] In alternative embodiments, the common control member comprises a shaft, wherein each of the valve members in a given level is arranged on a cylinder, and rotation of the control member causes rotation of the cylinder, thereby opening or closing the valves. In such embodiments, the drain valves of all levels are aligned and are arranged on respective cylinders, and the rotation of the control member causes rotation of each of the cylinders simultaneously, and the method further comprises rotating the control member to thereby open each of the valves in all levels.

[0054] The invention further provides:

[0055] An electrolyzer comprising:

[0056] -a plurality of vertically stacked electrolysis cells;

[0057] -one or more electrolyte supply tubes adjacent to said plurality of electrolysis cells and having a plurality' of fluid outlets configured to discharge an electrolyte solution from said one or more electrolyte supply tubes to each of said plurality of electrolysis cells; and

[0058] -each of the cells being provided with one or more drain assemblies, each drain assembly comprising a drain basin equipped with a drain valve, such that some or all drain valves in a given set of assemblies are engaged by a common control member configured and operable to actuate each of the drain val ves between a closed and an open position.

[0059] The electrolyzer further comprises a plurality of electrodes connectable to one or more electrical power sources and configured to pass electric current through the electrolyte solution introduced into said electrolysis cells via said outlets. In some configurations of an electrolyzer accoridng to the invention, each of the drain assemblies is external to the cells and is configured and operable to empty an amount of the electrolyte solution in the cells or its complete volume.

[0060] In some configurations of an electrolyzer accoridng to the invention, the vertically stacked electrolysis cells have overflow slots for control of the electrolyte level in each tray and allow excess fluid to flow into the common drain assemblies.

[0061] In some configurations of an electrolyzer accoridng to the invention, the drains within a given set are aligned along a common vertical axis and are fluidically coupled together to define a drainage conduit.

[0062] In some configurations of an electrolyzer accoridng to the invention, the drain valves of different cells are coaxially aligned and engaged by a common control member configured and operable to activate each of the drains valves within the set to allow the electrolyte solution within the drain basins to gravitationally empty or flow out.

[0063] In some configurations of an electrolyzer accoridng to the invention, the common control member is a threaded member having a length to engage a threaded valve member of each drain, such that rotation of the common control member causes rotation of the threaded valve member, thereby moving the valve member and opening the valve.

[0064] In some configurations of an electrolyzer accoridng to the invention, the electrolyte supply tubes have outlets sized so as to provide a substantially equal volume of electrolyte fluid to cells at different heights in the stack.

[0065] In some configurations of an electrolyzer accoridng to the invention, the vertically stacked electrolysis cells are arranged in levels having a polygonal configuration, with the drain assemblies arranged at an interior of the polygon and the electrolyte supply tubes arranged at an exterior of the polygon.

[0066] In some configurations of an electrolyzer accoridng to the invention, each electrolyte supply tube feeds two adjacent drain assemblies.

[0067] In some configurations of an electrolyzer accoridng to the invention, every two adjacent electrolysis cells share a drain basin and drain valve.

[0068] In some configurations of an electrolyzer accoridng to the invention, the common control member comprises a shaft, wherein each of the valve members in a given level is arranged on a cylinder, and rotation of the control member causes rotation of the cylinder, thereby opening or closing the valves. In some configurations of an electrolyzer accoridng to the invention, the valve members of all levels are aligned and are arranged on respective cylinders, and the rotation of the control member causes rotation of each of the cylinders simultaneously, thereby opening or closing each of the valves in all levels.

[0069] In some configurations of an electrolyzer accoridng to the invention, the vertically stacked electrolysis cells are arranged in levels having a polygonal configuration, with overflow slots that control the electrolyte level in each tray and allow excess fluid to flow into the common drain assemblies arranged at an interior of the polygon.

[0070] A method of electrolysis is also disclosed, the method comprising: filling electrolyte solution from one or more electrolyte supply tubes into vertically stacked electrolysis cells of an electrolyzer, wherein said filling is performed by discharging the electrolyte solution from one or more vertically oriented electrolyte supply tubes that are adjacent to the electrolysis cells into the respective electrolysis cells, and wherein each cell is filled directly from the electrolyte supply tubes without diverting electrolyte solution from cell to cell, activating electrical power sources to thereby pass electric current through the electrolyte solution introduced into said electrolysis cells, thereby producing at least one of hydrogen or oxygen; and following production of at least one of hydrogen or oxygen, simultaneously gravitationally draining the electrolyte solution from the electrolysis cells into a common drain, without diverting electrolyte solution between cells.

[0071] In some configurations of a method accoridng to the invention, the method further comprising performing each of the steps on an array of stacks of electrolysis cells, and further comprising, during production of the at least one of hydrogen or oxygen, forming a gas barrier of hydrogen or oxygen between horizontally adjacent stacks, to thereby prevent shunt currents from flowing from one stack to an adjacent stack.

[0072] In some configurations of a method accoridng to the invention, the method further comprising maintaining a ratio of fluid to gas identical in any given stack of the electrolyzer by capturing gas generated at any given stack of the electrolyzer without passing the generated gas through a different stack of the electrolyzer.

[0073] In some configurations of a method accoridng to the invention, each of the cells is provided with one or more drain assemblies, each drain assembly comprising a drain basin equipped with a drain valve, such that some or all drain valves in a given set of assemblies are engaged by a common control member, and the draining step comprises actuating the common control member to thereby transition the drain valves from a closed position to an open position.

[0074] In some configurations of a method accoridng to the invention, drains within a given set are aligned along a common vertical axis and are fluidically coupled together to define a drainage conduit, and the method comprises draining electrolyte solution from each ceil into one or more of the drainage conduits.

[0075] In some configurations of a method accoridng to the invention, the common control member is a threaded member having a length to engage a threaded valve member of each drain, and wherein the method further comprises rotating the common control member to thereby move the valve member of each drain and open the valves.

[0076] In some configurations of a method accoridng to the invention, the common control member comprises a shaft, wherein each of the valve members in a given level is arranged on a cylinder, and rotation of the control member causes rotation of the cylinder, thereby opening or closing the valves.

[0077] In some configurations of a method accoridng to the invention, the drain valves of all levels are aligned and are arranged on respective cylinders, and the rotation of the common control member causes rotation of each of the cylinders simultaneously, and the method further comprises rotating the control member to thereby open each of the valves in all levels.

[0078] BRIEF DESCRIPTION OF DRAWINGS

[0079] In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0080] Fig i is a perspective view of a first embodiment of a vertically stacked electrolysis system, according to embodiments of the present disclosure;

[0081] Fig. 2 is a perspective view of the electrolysis system of Fig. 1 with the case removed;

[0082] Fig. 3 illustrates a single layer of the electrolysis system of Fig. 1;

[0083] Fig. 4 illustrates a vertical cross section of the electrolysis system of Fig. 1; Fig- 5 illustrates a single container for housing one of the electrolysis cells of the electrolysis system of Fig. 1;

[0084] Fig- 6 illustrates a perspective view of a second embodiment of a vertically stacked electrolysis system, according to embodiments of the present disclosure;

[0085] Fig. 7 illustrates a bottom view of the electrolysis system of Fig. 6;

[0086] Fig. 8 illustrates a cross-section view of the electrolysis system of Fig. 6;

[0087] Fig. 9 illustrates an interior ring of the electrolysis system of Fig. 6; and

[0088] Fig. 10 illustrates a single container for housing one level of the electrolysis cells of the electrolysis system of Fig. 6.

[0089] DETAILED DESCRIPTION OF EMBODIMENTS

[0090] Figs. 1-5 depict a system 100 comprising stacked electrolysis cells 103. Fig. 1 depicts a perspective view of the system including an exterior case; Fig. 2 depicts the same system with the case removed; Fig. 3 illustrates one level of the stack; Fig. 4 illustrates a cross-section view of the system, and Fig. 5 depicts a tray for a single level of the electrolysis system.

[0091] In the illustrated embodiment 100, there are three stacked cells. The depiction of three cells is merely illustrative; there may also be as few as two cells, and as many as tens, or even a greater number, of cells in the stack. In addition, in the illustrated embodiment, only a single cell is present on each horizontal level. In alternative embodiments, multiple cells may be present on each horizontal level, with the cells on each level being connected in series or in parallel.

[0092] Cells 103 are contained in case 101. Each cell is contained within a tray 104 (illustrated in Fig. 5). The cells 103 contain two electrodes, as known to those of skill in the art. In particular embodiments, the electrodes are those that would be commonly used in E-TAC or E-E systems. In the presence of electrolyte fluid, and for E-TAC systems, the cells may produce hydrogen or oxygen, depending on the temperature of the electrolyte fluid and environmental factors, as is known from previous descriptions of E- TAC systems. Alternatively, the cells may be operated by reversing the polarity to produce oxygen.

[0093] The cells 103 have electrolyte supply tubes 113 that run the full height of the stack. Supply tubes 113 have outlets (not shown) near the top of each cell 103. The outlets supply each cell with a volume of an electrolyte solution. Electrolyte solution may be pumped into supply tubes 113 from the top thereof. The electrolyte solution that enters the supply tubes 113 allowed to exit each supply tube 113 through the outlets to fill the cells 103 on each level. The outlets are sized to allow the fluid to flow in a similar flow rate into each tray, considering that the pressure in the lower trays is slightly higher than the pressure in the upper trays due to the larger hydrostatic pressure at the lower section of the column during the filling operation. Thus, for example, the outlets may be slightly smaller in diameter at lower levels of the stack and larger in diameter at upper levels of the stack. Once the trays are filled with electrolyte solution, the supply tubes are closed to electrolyte solution, and may be used to capture and guide released gases (hydrogen or oxygen) up and out of the system.

[0094] In the event that a cell is overfilled with electrolyte solution, each tray has an overflow slot that controls the fluid level in the tray. The extra fluid flows out of the tray into the drain sets 111.

[0095] System 100 is equipped with one or more side drain sets 111. In the illustrated embodiment, there are two side drain sets 111 for each cell 103, although more or fewer could be provided. Each side drain set 111 is provided with a side drain basin 105 for each level, wherein each cell 103 is fluidically connected to a side drain basin 105 aligned in each set. All drain basins 105 in a set 111 are aligned along a common axis. Each drain set 111 is provided with a drain valve (not shown).

[0096] In the exemplified configuration, each drain valve has a threaded valve member 110. The valves are operated by a control member 107 that in this example is a screw with threads that engages the threaded member of the drain valves. The control member 107 in this example is aligned along a vertical axis, engaging each valve stack, and may operate each of the valves in unison. When it is desired to drain the electrolyte fluid, the control member 107 is operated, thereby rotating the threaded members 110 of the valves and opening the drain valves (now shown). The fluid drains into each side drain basin 105 simultaneously. The flow rate of the draining fluid may be controlled by varying the diameter of the drain valves as well as the size of the drain basins and relative to the volume of electrolyte fluid in each cell. Because the side drain basins 105 are arranged on a periphery of each of the cells 103, and share a common axis, all of the electrolyte fluid drains out via the side drain basins, without reentering different cells 103 in the stack. As a result, no shunt currents may form between adjacent cells. Following draining of the cells, the electrolyte fluid is collected from below. The electrolyte fluid then may be recycled by being pumped back into the electrolysis system, optionally at a different temperature, as desired.

[0097] Each of the cells 103 has a plurality of electrodes connectable to one or more electrical power sources and configured to pass electric current through the electrolyte solution introduced into said electrolysis cells via said outlets. When the electric current is operational, the cell 103 hydrolyzes water to produce hydrogen or oxygen, depending on the temperature and environmental conditions of the cell and electrolyte, as is known to those of skill in the art. The cells may be arranged with a small vertical space therebetween (e.g. around 10 mm) to enable the gases to exit the cells from above, and either ri se via the empty electrolyte supply tubes 113 or within the space between the cells 103 and the exterior case 101.

[0098] Fig- 2 illustrates a path 121 of electrolyte fluid that drains through a drain set 111, from the uppermost electrolysis cell through the respective side drain basins 105 and valves of the lower cells 103. The drains within a given set 111 are aligned along a common vertical axis and are fluidically coupled together to define a drainage conduit. Although, for clarity, only the path of electrolyte fluid from the uppermost cell is illustrated, it is understood that electrolyte flows from the other cells in the same manner. Once the electrolyte has existed the cells, it may be recycled and pumped back into the cells via electrolyte supply tubes 113.

[0099] Figs. 6-10 depict a second embodiment of a vertically stacked electrolysis system 200. Fig. 6 depicts an upper perspective view, Fig. 7 depicts a lower perspective view, Fig. 8 depicts a cross-section view and illustrates operation of the control member, Fig. 9 is a close-up view of the drain system, and Fig. 10 illustrates the tray for holding each of the cells within a given level.

[0100] The operation of system 200 is fundamentally similar to that of system 100, including the separation between supply tubes and drains, the absence of any flow of electrolyte from one cell to another cell during operation thereof, the separation between levels allowing for capture of gases without flowing of the gases through other cells, and the simultaneous filling and discharge of electrolyte fluid for all cells in the stack. The differences between system 200 and system 100 relate to the configuration of the cells, drains, and filling tubes on each level of the stack. In the embodiment of Figs. 6-10, the cells are arranged in levels having a polygonal configuration. While the term “polygonal” is used here in its conventional understanding of having multiple sides, it is understood that the sides need not be drawn in straight lines and may also be arranged as curves. The drain assemblies are arranged at an interior of the polygon, where they are controlled by a single control member. The electrolyte supply tubes are arranged at an exterior of the polygon. Each layer of electrolysis cells may consist of several stacks in a single tray, each in its own isolated electrolyte container, that may be electrically connected either in series or in parallel. All stacks in a given tray and throughout the column of trays are filled and drained simultaneously.

[0101] Referring to Figs. 6-10, electrolysis system 200 includes a plurality of cells 203. Electrodes 219 are illustrated in each cell 203. The cells are arranged in a vertical stack having more than one level (two levels are shown in the present embodiment). In addition, there are multiple cells 203 on each horizontal level. In the illustrated embodiment, there are eight cells on each level. Although not shown, this embodiment may also have an exterior case, which may be used to trap produced hydrogen and oxygen. In addition, there are a plurality of supply tubes 213. In the illustrated embodiment, there are four supply tubes 213 for the eight cells 203, with each supply tube 213 having two outlets 214 on each level, each directed to a different cell 203. As discussed above, the outlets may have slightly different diameters depending on the height of the level, so as to ensure even filling of all levels.

[0102] The cells 203 share a common drain system 211 configured at an interior of each level of cells 203. The drain system includes a series of drain basins 205 which draw electrolyte fluid from the electrolysis cells 203 to a common central drain. More specifically, each cell has an exit 229 (shown in Fig. 10) which leads to a shared drain 209 for two adjacent cells. The shared drain 209 is closed by a valve member 210, which is mounted on ring 223. Cylinder 223 is rotatable through operation of control member 207. When it is desired to open the drains, control member 207 is rotated, as illustrated in Fig. 8. The rotation of the control member causes rotation of the cylinder 223, which thereby moves the valve members 210 from the outlets of the shared drains 209. As a result, electrolyte fluid is emptied into the interior cavity. The electrolyte fluid may be collected from the bottom of the interior cavity and pumped back into the supply tubes 213 for re-use, as desired.

[0103] Each cell has a top opening that controls the level of fluid in the respective tray. The excess fluid flows into the common drain of all the trays. Fig- 8 illustrates a path 231 of electrolyte fluid, from a cell 203, through an opening 229 in the tray 227, to a shared drain 209, through the opened valve, and downward into the cavity.

[0104] In the illustrated embodiment, a single control member 207 opens all drains on all levels. In alternative embodiments, there may be multiple control members, with each of the control members controlling only a portion of the valves for the respective drains.

[0105] In the illustrated embodiment, the drain assemblies are at an interior of the polygon forming the electrolyzer stack and the electrolyte supply tubes are at an exterior of the polygon forming the electrolyzer stack. Advantageously, in this embodiment, all of the drain assemblies may be controlled by a single control member. Theoretically, however, it is possible to switch this arrangement, with the drain assemblies being configured on the outside and the supply tubes being configured on the inside.

[0106] In the illustrated embodiments, the method of operation of the control member for the drain assemblies is entirely mechanical. In alternative embodiments, the control member may be operated with an electromagnet, or via any other system for controlling the opening or closing of valves.

[0107] An electrolysis production location may include an array of stacks such as those of Figs. 1-5 or Figs. 6-10. Each stack is separated by a gas (either hydrogen or oxygen, depending on which gas is being produced), which prevents electrical shunt currents from flowing from one stack to its neighbor.

[0108] In addition, the above embodiment provides the exact same chemical environment in all the stacks in a given reactor. All the stacks are at the same temperature and the same pressure. Furthermore, the gas produced in any given stack does not pass through a different stack within the reactor. Hence the ratio of fluid to gas in any given stack within the reactor is identical. Finally, the reactor consisting of plurality of stacks, serves as a gas - liquid separator in the whole system, alleviating the need for a gas-liquid separator.

[0109] In both the embodiments of Figs. 1-5 and the embodiments of Figs. 6-10, the volume of the cup or tray forming the electrolysis cell is selected so as to allow extra electrolyte surrounding the electrodes, so that the temperature rise in each cell is limited to the level determined optimal for the electrode operation. Typical temperature rise in the electrodes may be 5 - 10 degrees during charging and discharging operation.

[0110] The disclosed apparatuses may be used as part of (E-TAC) production cycle, in which electrolyte is sequentially pumped into each electrolysis cell at different temperatures so as to produce different gases at different points in the cycle. Alternatively, the disclosed apparatuses may be used as part of a (E-E) production cycle that uses reverse polarity, so as to produce different gases at different points in the cycle. Each time it is desired to flow a different temperature electrolyte into the cells, the cells may be drained and refilled, while avoiding shunt currents, due to the presence of gas in between cells during operation, and due to the simultaneous filling and draining of all cells.

Claims

CLAIMS:

1. An electrolyzer comprising:-a plurality of vertically stacked electrolysis cells;-one or more electrolyte supply tubes adjacent to said plurality of electrolysis cells and having a plurality of fluid outlets configured to discharge an electrolyte solution from said one or more electrolyte supply tubes to each of said plurality of electrolysis cells; and-each of the cells being provided with one or more drain assemblies, each drain assembly comprising a drain basin equipped with a drain valve, such that some or all drain valves in a given set of assemblies are engaged by a common control member configured and operable to actuate each of the drain valves between a closed and an open position.

2. The electrolyzer according to claim 1, wherein each of the drain assemblies is external to the cells and is configured and operable to empty an amount of the electrolyte solution in the cells or its complete volume.

3. The electrolyzer according to claim 1, wherein the vertically stacked electrolysis cells have overflow slots for control of the electrolyte level in each tray and allow excess fluid to flow into the common drain assemblies.

4. The electrolyzer according to claim 1, wherein the drains within a given set are aligned along a common vertical axis and are fluidically coupled together to define a drainage conduit.

5. The electrolyzer according to claim 1, wherein the drain valves of different cells are coaxially aligned and engaged by a common control member configured and operable to activate each of the drains valves within the set to allow the electrolyte solution within the drain basins to gravitationally empty or flow out.

6. The electrolyzer according to claim 5, wherein each drain valve comprises a threaded (movable) valve member, and wherein the common control member is a threaded member having a length to engage a threaded valve member of each drain, such that rotation of the common control member causes rotation of the threaded valve member, thereby moving the valve member and opening the valve.

7. The electrolyzer according to claim 1, wherein the electrolyte supply tubes have outlets sized so as to provide a substantially equal volume of electrolyte fluid to cells at different heights in the stack.

8. The electrolyzer according to claim 1, wherein the vertically stacked electrolysis cells are arranged in levels having a polygonal configuration, with the drain assemblies arranged at an interior of the polygon and the electrolyte supply tubes arranged at an exterior of the polygon.

9. The electrolyzer according to claim 8, wherein each electrolyte supply tube feeds two adjacent drain assemblies.

10. The electrolyzer according to claim 8, wherein every two adjacent electrolysis cells share a drain basin and drain valve.

11. The electrolyzer according to claim 6, wherein the common control member comprises a shaft, wherein each drain valve comprises a movable valve member, wherein each of the valve members in a given level is arranged on a cylinder, and rotation of the control member causes rotation of the cylinder, thereby opening or closing the valves.

12. The electrolyzer according to claim 11, wherein the valve members of all levels are aligned and are arranged on respective cylinders, and the rotation of the control member causes rotation of each of the cylinders simultaneously, thereby opening or closing each of the valves in all levels.

13. The electrolyzer according to claim 1, wherein the vertically stacked electrolysis cells are arranged in levels having a polygonal configuration, with overflow7slots that control the electrolyte level in each tray and allow excess fluid to flow into the common drain assemblies arranged at an interior of the polygon.

14. A method of electrolysis, the method comprising: filling electrolyte solution from one or more electrolyte supply tubes into vertically stacked electrolysis cells of an electrolyzer, wherein said filling is performed by discharging the electrolyte solution from one or more vertically oriented electrolyte supply tubes that are adjacent to the electrolysis cells into the respective electrolysis cells, and wherein each cell is filled directly from the electrolyte supply tubes without diverting electrolyte solution from cell to cell; activating electrical power sources to thereby pass electric current through the electrolyte solution introduced into said electrolysis cells, thereby producing at least one of hydrogen or oxygen; and following production of at least one of hydrogen or oxygen, simultaneously gravitationally draining the electrolyte solution from the electrolysis cells into a common drain, without diverting electrolyte solution between cells.

15. The method according to claim 14, further comprising performing each of the steps on an array of stacks of electrolysis cells, and further comprising, during production of the at least one of hydrogen or oxygen, forming a gas barrier of hydrogen or oxygen between horizontally adjacent stacks, to thereby prevent shunt currents from flowing from one stack to an adjacent stack.

16. The method according to claim 14, further comprising maintaining a ratio of fluid to gas identical in any given stack of the electrolyzer by capturing gas generated at any given stack of the electrolyzer without passing the generated gas through a different stack of the electrolyzer.

17. The method according to claim 14, wherein each of the cells i s provided with one or more drain assemblies, each drain assembly comprising a drain basin equipped with a drain valve, such that some or all drain valves in a given set of assemblies are engaged by a common control member, and the draining step comprises actuating the common control member to thereby transition the drain valves from a closed position to an open position.

18. The method according to claim 17, wherein drains within a given set are aligned along a common vertical axis and are fluidically coupled together to define a drainage conduit, and the method comprises draining electrolyte solution from each cell into one or more of the drainage conduits.

19. The method according to claim 18, wherein each drain valve comprises a threaded valve member, the common control member is a threaded member having a length to engage the threaded valve member of each drain, and wherein the method further comprises rotating the common control member to thereby move the valve member of each drain and open the valves.

20. The method according to claim 14, wherein each drain valve comprises a movable valve member, the common control member comprises a shaft, wherein each of the valve members in a given level is arranged on a cylinder, and rotation of the control member causes rotation of the cylinder, thereby opening or closing the valves.

21. The method according to claim 20, wherein the drain valves of all levels are aligned and are arranged on respective cylinders, and the rotation of the common control member causes rotation of each of the cylinders simultaneously, and the method further comprises rotating the control member to thereby open each of the valves in all levels.

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