Devices, systems, and methods for electrochemically purifying hydrogen

Abstract

The present invention provides a hydrogen gas purifier electrochemical cell, a system for purifying hydrogen gas, and a method for purifying hydrogen gas. [Solution] The cell 10, system, and method utilize double membrane electrode (DMEA) electrochemical cells 24, 26 that enhance purification while avoiding the complexity and cost of conventional cells. The purity of the hydrogen gas produced by the cell, system, and method can be improved by removing at least some intermediate gas impurities from the cell. The purity of the hydrogen gas produced by the cell, system, and method can also be increased by introducing hydrogen gas into the cell to replenish any lost hydrogen. A water electrolytic electrochemical cell and a method for electrolyzing water to produce hydrogen gas are also disclosed.

Description

Technical Field

[0001] Cross-Reference to Related Applications

[0001] This application claims priority to pending U.S. Patent Application No. 17 / 934,341 filed on September 22, 2022, the disclosure of which is incorporated herein in its entirety by reference. Background Art

[0002] Background of the Invention Technical Field

[0002] The present invention generally relates to electrochemical purification and / or compression of hydrogen gas. Specifically, aspects of the present invention include electrochemical cells, systems, and methods for purifying and / or compressing hydrogen gas that use one or more membrane electrode assemblies (MEAs) within a single MEA cell, eliminating the need for external handling of gas flow between separate MEA cells.

[0003] Description of the Prior Art

[0003] As is known in the art, high-purity hydrogen, that is, hydrogen gas having a hydrogen content exceeding 99.99 volume percent, has many applications. However, hydrogen gas is generally often mixed with other undesirable gases, such as nitrogen, argon, carbon dioxide, oxygen, and carbon monoxide, among others. Accordingly, there is a need in the art for improved methods of separating hydrogen gas from undesirable gases to provide hydrogen gas in a purer form.

[0004]

[0004] Hydrogen purification is not easily achieved. Hydrogen gas is generally difficult to separate from other gases because, inter alia, hydrogen molecules are relatively small and hydrogen gas is flammable. Existing means for purifying hydrogen gas from undesirable non-hydrogen gases include molecular sieves, membranes, palladium membranes, and electrochemical hydrogen pumps (EHPs).

[0005]

[0005] Molecular sieves separate hydrogen molecules via selective adsorption, and preferentially retain certain molecules over others. However, in many cases, molecular sieve adsorption systems only have an undesirable minor effect on hydrogen gas purity. One such case is the separation of nitrogen gas (N₂) and hydrogen gas (H₂).

[0006]

[0006] Palladium selectively allows only hydrogen atoms to pass through, generating high-purity hydrogen. However, palladium is expensive, this process requires compressed gas, and a high hydrogen recovery rate requires high pressure and / or a large amount of palladium.

[0007]

[0007] Electrochemical hydrogen pumps (EHP) selectively extract hydrogen from a mixture of hydrogen gas and other gases such as nitrogen and argon. However, other undesirable gases typically diffuse across the pump membrane, which consequently limits the purity of the hydrogen gas. As a result, multiple individual electrochemical hydrogen pumps can be used, each EHP having an associated housing, cell stack, supply conduit, and exhaust conduit in series, among other separate hardware and control systems, to purify the hydrogen gas stream twice, thus attempting to increase hydrogen gas purity. However, such an arrangement requires multiple separate electrochemical pump cell stacks and multiple sets of electrochemical stack hardware connected to each other. This undesirably increases the complexity of the system and increases costs.

[0008]

[0008] Another approach for purifying hydrogen is to increase the membrane thickness in an electrochemical cell. However, increasing membrane thickness is typically only limited to reducing impurity diffusion across the membrane as a function of membrane thickness. Other approaches for purifying hydrogen gas suffer from undesirable gas pressure reduction, require a plurality of undesirable pumps, recover less hydrogen gas, consume more energy, and / or do not produce high-purity hydrogen gas required by today's hydrogen gas users such as the semiconductor industry.

[0009]

[0009] Therefore, there is a need in the art for improved hydrogen purification systems, methods, and devices. [Overview of the project] [Problems that the invention aims to solve]

[0010] Summary of the Invention

[0010] Embodiments of the present invention address this recognized need by providing improved hydrogen purification that can meet and exceed the hydrogen gas purity required by various applications in their various embodiments. Embodiments of the present invention utilize unique combinations of membrane electrode assemblies (MEAs) or "dual" MEAs (DMEAs), which are shown to provide the improved hydrogen gas purity required by today's users. [Means for solving the problem]

[0011]

[0011] One embodiment of the present invention is a hydrogen gas purifier cell comprising: a first membrane electrode assembly (MEA) comprising: a first anode disposed in contact with a first gas stream having a first hydrogen gas content and a first impurity gas content, the first anode containing a catalyst, for example, a platinum group catalyst, adapted to oxidize at least a portion of the first hydrogen gas content to produce hydrogen ions and electrons; a first electrolyte, for example, an acidic electrolyte, disposed and adapted to receive and transfer at least a portion of the hydrogen ions produced by the first anode; and a first cathode disposed to receive at least a portion of the hydrogen ions transferred by the first electrolyte, the first cathode containing a catalyst adapted to reduce at least a portion of the hydrogen ions to produce a second gas stream having a second hydrogen gas content greater than the first hydrogen gas content and a second impurity gas content less than the first impurity gas content; The second MEA comprises a first MEA, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second electrolyte, for example, an acidic electrolyte, a second electrolyte, a second anode, a second cathode anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode, a second anode

[0012]

[0012] In one embodiment, the purifier cell may further include at least one passage between the first electrolyte and the second electrolyte to discharge at least a portion of the second gas flow. For example, the at least one passage may be located between the first cathode and the second anode. In one embodiment, the at least one passage located between the first cathode and the second anode may include a space or void between the mating surfaces of the first cathode and the second anode. In another embodiment, the purifier cell may further include a gas permeable layer or gas diffusion layer (GDL) between the first cathode and the second anode, the GDL being at least a portion of the second gas flow This can also provide at least one passage for discharging a portion of the gas. In another embodiment, a gas distribution or flow field insert having or not having a GDL can be placed between the first cathode and the second anode to facilitate or enhance the distribution of the second gas flow across the surface of the second anode. The flow field insert may be a conductive porous or perforated plate, e.g., a porous or perforated metal plate, or a screen-like insert, e.g., a metal screen-like insert, arranged and adapted to provide at least a portion of the gas distribution around the surface of the second anode. In another embodiment, the at least one passage for discharging at least a portion of the second gas flow may be at least one channel adjacent to the first cathode, the second anode, or both.

[0013]

[0013] In another embodiment, the purifier cell may further include or comprise at least one passage between the first electrolyte and the second electrolyte for introducing a hydrogen-containing gas into the second gas flow. For example, at least one passage may be located between the first cathode and the second anode. In one embodiment, at least one passage may be the space or void between the mating surfaces of the first cathode and the second anode. In one embodiment, the purifier cell may further comprise a gas permeable layer or gas diffusion layer (GDL) between the first cathode and the second anode, the GDL providing at least one passage for introducing a hydrogen-containing gas into the second gas flow. In another embodiment, a gas distribution or flow field insert having or not having a GDL may be positioned between the first cathode and the second anode to facilitate or enhance the distribution of the second gas flow across the surface of the second anode. The flow field insert may be a porous or perforated plate, such as a porous or perforated metal plate, or a screen-like insert, such as a metal screen-like insert, which is arranged and fitted to provide at least some gas distribution around the surface of the second anode.

[0014]

[0014] In another embodiment, at least one passage for introducing hydrogen-containing gas into the second gas flow may comprise at least one channel adjacent to the first cathode, the second anode, or both.

[0015]

[0015] In one embodiment, the first gas flow may have a first gas pressure, and the third gas flow may have a third gas pressure, the third gas pressure being greater than the first gas pressure. In another embodiment, the third gas pressure may be lower than the first gas pressure.

[0016]

[0016] Another embodiment of the present invention is a hydrogen gas purification system comprising or including at least one hydrogen gas purification cell as disclosed herein and at least two conductive plates, one of which is attached to a first end of the at least one hydrogen gas purification cell and the other of which is attached to a second end of the at least one hydrogen gas purification cell on the opposite side of the first end. For example, in one embodiment, the at least one hydrogen gas purification cell may include a plurality of hydrogen gas purification cells, for example, a stack of hydrogen gas purification cells.

[0017]

[0017] Another embodiment of the present invention is a method for reducing the impurity gas content of a gas stream having a hydrogen gas content and an impurity gas content, the method comprising: introducing a first gas stream having a first hydrogen content and a first impurity gas content into a first anode containing a catalyst; catalytically oxidizing at least a portion of the first hydrogen gas content in the first anode to generate hydrogen ions and electrons; transferring at least a portion of the hydrogen ions and at least a portion of the impurity gas content through a first electrolyte to a first cathode containing a catalyst; and catalytically reducing at least a portion of the hydrogen ions transferred through the first electrolyte in the first cathode to a second hydrogen content greater than the first hydrogen content. The method comprises or includes: generating a second gas stream having a quantity and a second impurity gas content less than that of a first impurity gas content; introducing the second gas stream to a second anode having a catalyst; catalytically oxidizing at least a portion of the second hydrogen gas content in the second gas stream at the second anode to generate hydrogen ions and electrons; transferring at least a portion of the hydrogen ions generated at the second anode and at least a portion of the second impurity gas content to the second cathode through a second electrolyte; and catalytically reducing at least a portion of the hydrogen ions transferred through the second electrolyte at the second cathode to generate a third gas stream having a third hydrogen content greater than that of the first hydrogen content and a third impurity gas content less than that of the first impurity gas content.

[0018]

[0018] In one embodiment, the method may further include removing at least a portion of the second gas flow to produce a reformed gas flow having a non-hydrogen gas partial pressure lower than the non-hydrogen gas partial pressure in the second gas flow. In another embodiment, introducing the second gas flow to the second anode includes introducing the reformed gas flow to the second anode. In one embodiment, removing at least a portion of the second gas flow may be carried out by removing at least a portion of the second gas flow through a passage between the first electrolyte and the second electrolyte, for example, the passage may be located between the first cathode and the second anode. In one embodiment, the passage for removing at least a portion of the second gas flow may be the space or void between the mating surfaces of the first cathode and the second anode. In another embodiment, removing at least a portion of the second gas flow may be carried out by removing at least a portion of the second gas flow through a gas diffusion layer (GDL) and / or flow field insert located between the first cathode and the second anode. In another embodiment, the removal of at least a portion of the second gas flow may be carried out by removing at least a portion of the second gas flow through the first cathode, the second cathode, or at least one channel adjacent to both.

[0019]

[0019] In another embodiment, the method may further include introducing a portion of hydrogen gas into a second gas stream, for example, a “replenishment” gas stream. In one embodiment, introducing a portion of hydrogen gas into the second gas stream can replenish at least a portion of the hydrogen gas removed from the second gas stream. In one embodiment, the replenishment hydrogen gas stream may include at least a portion of a third gas stream having a third hydrogen content. For example, the third gas stream may be introduced into the second gas stream by diffusion through a second electrolyte. This diffusion through the second electrolyte may be referred to as “backdiffusion” of at least a portion of the third gas stream having a third hydrogen content into the second gas stream through the second electrolyte.

[0020]

[0020] In one embodiment, by employing the electrochemical cell and method disclosed herein, the purified hydrogen gas produced, for example, the content of a third impurity gas, may be at least 100 times lower by volume than the impurity content of the input gas, for example, the first impurity gas. In another embodiment, the impurity gas content of the produced hydrogen gas may be at least 1 / 1000, 1 / 10,000, 1 / 100,000, or even less than 1 / 100,000 of the impurity content of the first hydrogen gas stream.

[0021]

[0021] In one embodiment, for example, the impurity gas content of the hydrogen gas produced by any of the methods, cells, and systems of the present invention in the third gas stream may be up to parts per hundred million [ppm], i.e., the third gas stream may contain up to 100 ppm of impurity gas. In another embodiment of the present invention, the impurity gas content of the produced hydrogen gas may be up to 20 ppm, or up to 10 ppm, or up to 5 ppm, or up to 2 ppm, or up to 1 ppm. In yet another embodiment of the present invention, the impurity gas content of the produced hydrogen gas may be up to parts per billion [ppb] (i.e., up to 0.750 ppm), or up to 500 ppb, or up to 200 ppb, or even up to 100 ppb. As is known in the art, the impurity content of these generated hydrogen gases, for example, 1,000 times lower than the impurity gas content of the first gas stream, or impurity gas content in ppm or ppb units, is typically on a "dry basis." As is known in the art, "on a dry basis" means that some water vapor may still be present in the generated gas stream, for example, that has not yet been reduced or removed in a subsequent drying process.

[0022]

[0022] Another embodiment of the present invention is a method for reducing the impurity gas content of a gas stream having a hydrogen gas content and an impurity gas content, the method comprising: introducing a first gas stream having a first hydrogen content and a first impurity gas content into a first membrane electrode assembly (MEA) having a first anode containing a catalyst, a first electrolyte, and a first cathode containing a catalyst to generate a second gas stream having a second hydrogen gas content and a second impurity gas content; and passing the second gas stream directly through a second MEA having a second anode containing a catalyst, a second electrolyte, and a second cathode containing a catalyst to generate a third gas stream having a third hydrogen gas content greater than the first hydrogen content and a third impurity gas content less than the first impurity gas content.

[0023]

[0023] In one embodiment, the first MEA and the second MEA may be located within a hydrogen purification cell, and passing the second gas flow directly through the second MEA may include passing the second gas flow through the second MEA without allowing the second gas flow to leave the hydrogen purification cell.

[0024]

[0024] In one embodiment, the method may further include removing at least a portion of the second gas flow to produce a modified second gas flow having a reduced non-hydrogen gas partial pressure than the second gas flow, and then introducing the modified second gas flow having the reduced non-hydrogen gas partial pressure into the second MEA. In one embodiment, the method may further include introducing at least a portion of hydrogen gas into the second gas flow or the modified second gas flow.

[0025]

[0025] A further embodiment of the present invention is a hydrogen gas purifier cell comprising a membrane electrode assembly (MEA), the MEA comprising an anode positioned in contact with a first gas stream having a first hydrogen gas content and a first impurity gas content, and containing a catalyst adapted to oxidize at least a portion of the first hydrogen gas content to produce hydrogen ions and electrons; a first electrolyte positioned and adapted to receive and transfer at least a portion of the hydrogen ions received from the anode; and a double electrode positioned to receive at least a portion of the hydrogen ions transferred by the first electrolyte, the double cathode having a second hydrogen gas content by reducing at least a portion of the hydrogen ions The invention comprises or includes: a double electrode containing a catalyst adapted to generate a second gas flow and oxidize at least a portion of the second hydrogen gas content in the second gas flow to generate hydrogen ions and electrons; a second electrolyte arranged and adapted to receive and transfer at least a portion of the hydrogen ions received from the double electrode; and a cathode arranged to receive at least a portion of the hydrogen ions transferred by the second electrolyte, and containing a catalyst adapted to reduce at least a portion of the hydrogen ions to generate a third gas flow having a third hydrogen gas content greater than the first hydrogen gas content and a third impurity gas content less than the first impurity gas content.

[0026]

[0026] In one embodiment, the hydrogen gas purifier cell further includes at least one passage for removing at least a portion of the second gas stream. For example, the at least one passage for removing at least a portion of the second gas stream may be a double electrode, for example, a permeable gas-permeable diffusion layer of the double electrode, and / or a second electrolyte.

[0027]

[0027] In one embodiment, the hydrogen gas purifier cell converts at least a portion of the hydrogen gas into a second gas The system further includes at least one passage for introducing into the flow. For example, the at least one passage for introducing at least a portion of hydrogen gas may be a double electrode, e.g., a permeable, gas-permeable diffusion layer of the double electrode, and / or a second electrolyte via, for example, “reverse diffusion”.

[0028]

[0028] Further embodiments of the present invention are methods for purifying hydrogen gas, comprising: introducing a first gas stream having a first hydrogen gas content and a first impurity gas content into an anode containing a catalyst; catalytically oxidizing at least a portion of the first hydrogen gas content at the anode to generate hydrogen ions and electrons; transferring at least a portion of the hydrogen ions generated at the anode to a bielectrode through a first electrolyte; catalytically reducing at least a portion of the hydrogen ions transferred through the first electrolyte at the bielectrode to generate a second gas stream having a second hydrogen gas content; catalytically oxidizing at least a portion of the second hydrogen gas content in the second gas stream to generate hydrogen ions and electrons; transferring at least a portion of the hydrogen ions generated in the bielectrode to a cathode through a second electrolyte; and catalytically reducing at least a portion of the hydrogen ions transferred through the second electrolyte at the cathode to generate a third gas stream having a third hydrogen gas content greater than the first hydrogen gas content and a third impurity gas content less than the first impurity gas content.

[0029]

[0029] In one embodiment, the method may further include removing at least a portion of the second gas flow through, for example, at least one passage. For example, the at least one passage for removing at least a portion of the second gas flow may be a gas diffusion layer, a gas-permeable double electrode, and / or a second electrolyte via, for example, “reverse diffusion”.

[0030]

[0030] In one embodiment, the method may further include introducing at least a portion of hydrogen gas into the second gas stream, for example, through at least one passage. For example, the at least one passage for introducing at least a portion of hydrogen gas may pass through a gas diffusion layer, through a gas-permeable double electrode, and / or through the second electrolyte.

[0031]

[0031] A further embodiment of the present invention is a water electrolytic cell, comprising: a first membrane electrode assembly (MEA), a first anode disposed in contact with a first H2O-containing fluid stream, containing a catalyst adapted to oxidize at least a portion of the H2O in the first H2O-containing fluid stream to produce oxygen gas, hydrogen ions, and electrons; a first electrolyte disposed and adapted to receive and transfer at least a portion of the hydrogen ions produced by the first anode; and a first cathode disposed to receive at least a portion of the hydrogen ions transferred by the first electrolyte, containing a catalyst adapted to reduce at least a portion of the hydrogen ions to produce a second fluid stream containing hydrogen gas, the first ME A comprises or includes a second MEA, the second anode being configured to receive a second fluid flow containing hydrogen gas from a first cathode of the first MEA, the second anode containing a catalyst adapted to oxidize at least a portion of the hydrogen gas to produce hydrogen ions and electrons; a second electrolyte configured and adapted to receive and transfer at least a portion of the hydrogen ions produced by the second anode; and a second cathode being configured to receive at least a portion of the hydrogen ions transferred by the second electrolyte of the second MEA, the second cathode containing a catalyst adapted to reduce at least a portion of the hydrogen ions to produce a third fluid flow containing hydrogen gas.

[0032]

[0032] In one embodiment, the electrolytic cell may further include at least one passage between the first electrolyte and the second electrolyte to discharge at least a portion of the second fluid flow. For example, a passage for discharging a second fluid flow may be located between the first cathode and the second anode. For example, at least one passage located between the first cathode and the second anode may be a gap between the mating surfaces of the first cathode and the second anode, and / or a gas permeable layer (GDL) and / or flow field insert between the first cathode and the second anode.

[0033]

[0033] In another embodiment, the water electrolytic cell may further include at least one passage between the first electrolyte and the second electrolyte for introducing a hydrogen-containing gas into the second gas flow. For example, the passage for introducing hydrogen gas may be the gap between the mating surfaces of the first cathode and the second anode, and / or a GDL and / or flow field insert located between the first cathode and the second anode.

[0034]

[0034] Another embodiment of the present invention is a method for electrolyzing water, the method comprising: introducing a first H2O-containing fluid stream into a first anode containing a catalyst; catalytically oxidizing at least a portion of the H2O in the first H2O-containing fluid stream at the first anode to produce oxygen gas, hydrogen ions, and electrons; transferring at least a portion of the hydrogen ions through a first electrolyte to a first cathode containing a catalyst; and catalytically reducing at least a portion of the hydrogen ions that have moved through the first electrolyte at the first cathode to produce a second cathode containing hydrogen gas. The present invention comprises or includes generating a second fluid flow, introducing the second fluid flow containing hydrogen gas to a second anode containing a catalyst, catalytically oxidizing at least a portion of the hydrogen gas in the second fluid flow at the second anode to generate hydrogen ions and electrons, transferring at least a portion of the hydrogen ions generated at the second anode to the second cathode through a second electrolyte, and catalytically reducing at least a portion of the hydrogen ions that have moved through the second electrolyte at the second cathode to generate a third fluid flow containing hydrogen gas. According to embodiments of the present invention, the "fluid flow" may be a liquid flow, a gas flow, and / or a liquid and gas flow.

[0035]

[0035] In one embodiment, the method may further include removing at least a portion of the second fluid flow to produce a modified fluid flow having a non-hydrogen gas partial pressure lower than the partial pressure of non-hydrogen gas in the second fluid flow. The method may further include introducing the modified fluid flow to the second anode.

[0036]

[0036] In another embodiment, the method may further include introducing a portion of hydrogen gas into a second fluid flow, for example, the introduced hydrogen gas can replenish at least a portion of the hydrogen gas removed from the second fluid flow.

[0037]

[0037] A further embodiment of the present invention is a water electrolytic cell comprising or including a membrane electrode assembly (MEA), the MEA being an anode positioned in contact with a first H2O-containing fluid stream, the anode containing a catalyst adapted to oxidize at least a portion of the H2O in the first H2O-containing fluid stream to produce oxygen gas, hydrogen ions, and electrons; a first electrolyte positioned and adapted to receive and transfer at least a portion of the hydrogen ions produced by the anode; and a double electrode positioned to receive at least a portion of the hydrogen ions transferred by the first electrolyte, the double cathode being hydrogen A double electrode containing a catalyst adapted to reduce at least a portion of ON to generate a second gas stream having a second hydrogen gas content, and to oxidize at least a portion of the second hydrogen gas content in the second gas stream to generate hydrogen ions and electrons; a second electrolyte arranged and adapted to receive and transfer at least a portion of the hydrogen ions received from the double electrode; and a cathode arranged and adapted to receive at least a portion of the hydrogen ions transferred by the second electrolyte of the second MEA, and containing a catalyst adapted to reduce at least a portion of the hydrogen ions to generate a third fluid stream containing hydrogen gas. It is equipped with a cathode.

[0038]

[0038] Another embodiment of the present invention is a method for electrolyzing water, comprising: introducing a first H2O-containing fluid stream into an anode containing a catalyst; catalytically oxidizing at least a portion of the H2O in the first H2O-containing fluid stream at the anode to produce oxygen gas, hydrogen ions, and electrons; transferring at least a portion of the hydrogen ions produced at the anode to a bielectrode through a first electrolyte; catalytically reducing at least a portion of the hydrogen ions that have moved through the first electrolyte at the bielectrode to produce a second fluid stream having a second hydrogen gas content; catalytically oxidizing at least a portion of the second hydrogen gas content in the second gas stream to produce hydrogen ions and electrons; transferring at least a portion of the hydrogen ions produced in the bielectrode to a cathode through a second electrolyte; and catalytically reducing at least a portion of the hydrogen ions that have moved through the second electrolyte at the cathode to produce a third fluid stream having hydrogen gas.

[0039]

[0039] These and other aspects, features and advantages of the present invention will become apparent from the following detailed description of various aspects of the present invention in conjunction with the accompanying drawings.

[0040] Brief explanation of the drawing

[0040] Subject matter considered to be the present invention is specifically pointed out and explicitly claimed in the claims in the conclusions of this specification. The above and other objects, features and advantages of the present invention will be readily apparent from the following detailed description of embodiments of the invention in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0041] [Figure 1]

[0041] This is a schematic diagram of a hydrogen gas purification cell according to one aspect of the present invention. [Figure 2]

[0042] This is a schematic diagram of a hydrogen gas purification cell according to another aspect of the present invention. [Figure 3]

[0043] This is a schematic front view of a hydrogen purifier stack assembly having a hydrogen gas purifier cell shown in Figure 1 or Figure 2, according to an aspect of the present invention. [Figure 3A]

[0044] This is a detailed view of the hydrogen purifier stack assembly shown in Figure 3, identified by detail 3A shown in Figure 3. [Figure 3B]

[0045] This is a detailed view similar to Figure 3A, representing another aspect of the present invention. [Figure 4]

[0046] This is a schematic front view of a hydrogen purifier stack having a plurality of hydrogen purifier cells, as shown in Figure 1 and / or Figure 3, according to one aspect of the present invention. [Figure 5]

[0047] This is a schematic diagram of a hydrogen gas purification cell according to another aspect of the present invention. [Figure 6]

[0048] This is a schematic diagram of a hydrogen gas purification system having one or more hydrogen purifiers, each having one or more hydrogen purifier stacks, according to one aspect of the present invention, as shown in Figure 4. [Figure 7]

[0049] This is a schematic diagram of a water electrolytic cell according to another aspect of the present invention. [Figure 8]

[0050] This is a schematic diagram of a water electrolytic cell according to another aspect of the present invention. [Modes for carrying out the invention]

[0042] Detailed description of the invention

[0051] Figure 1 is a schematic diagram of a hydrogen gas purifier cell 10 according to one embodiment of the present invention. According to this embodiment, the purifier cell 10 receives a feed or first gas stream 12 having at least some hydrogen gas content 14 (i.e., diatomic hydrogen gas, H2) and at least some non-hydrogen gas 16, and is arranged and adapted to produce a gas stream 18 with a reduced non-hydrogen gas content, i.e., a gas stream 18 with a purer hydrogen gas content. The non-hydrogen gas 16 can typically include nitrogen (N2), argon (Ar), carbon monoxide (CO), methane (CH4), oxygen (O2), and / or carbon dioxide (CO2), among other gases. According to one embodiment of the present invention, the expression “non-hydrogen gas” can refer to a gas other than diatomic hydrogen gas H2. The gas stream 18 with a reduced hydrogen gas content is an exhaust gas This may be referred to as flow 18 or third gas flow 18. The third gas flow 18 may typically include an enhanced hydrogen gas content 20 and a reduced non-hydrogen gas content 22, for example, a higher purity hydrogen gas flow, e.g., a hydrogen gas flow having a non-hydrogen content of up to 100 ppm on a dry basis. In other embodiments of the present invention, the non-hydrogen content 22 of gas flow 18 may be up to 20 ppm, or up to 10 ppm, or up to 5 ppm, or up to 2 ppm, or up to 1 ppm. In addition to reducing the non-hydrogen gas content in gas flow 18, in embodiments of the present invention, gas flow 18 may typically have an increased hydrogen gas content 20, for example, in volume percentage, and an increased hydrogen gas pressure, for example, a pressure higher than the pressure of the supply gas flow 12. In one embodiment, the pressure of gas flow 18 may be lower than the pressure of gas flow 12. Since the desired function of the purifier cell 10 is to reduce or substantially eliminate the content of non-hydrogen gas 16, the non-hydrogen gas 16 may be referred to as “impurity gas” 16 or “first impurity gas” 16.

[0043]

[0052] As schematically shown in Figure 1, the hydrogen gas purifier cell 10 typically comprises a multilayer structure having components such as anodes and cathodes having thin planar or thin layered structures, and the structure shown in Figure 1 may include a side view or axial cross section of the purifier cell 10, which is not drawn to scale but is drawn to facilitate the disclosure of the present invention.

[0044]

[0053] According to aspects of the present invention, in order to provide a desired increased hydrogen gas content 20 and typically increased hydrogen gas pressure, the purifier cell 10 typically includes a first membrane electrode assembly (MEA) 24 and at least one second MEA 26. The first MEA 24 includes a first electrode 28, specifically a first "anode" 28 as referred to in the Art. The anode 28, and any anode disclosed herein, may typically be gas permeable, specifically hydrogen gas permeable, and at least a portion of the hydrogen gas content 14 and at least a portion of the non-hydrogen gas content 16 in the first gas stream 12 may pass through the anode 28, for example, in the axial direction as indicated by the arrows in the first gas stream 12. In addition, the anode 28, and any anode or cathode disclosed herein, may contain at least a portion of a catalyst, for example, hydrogen ions (H + A catalyst containing at least some platinum group metals, for example, a platinum-containing catalyst, which is capable of enhancing the oxidation of hydrogen to ), but in some embodiments, a non-platinum group metal-containing catalyst may be used for anode 28 and any anode or cathode disclosed herein. As is known in the art, a platinum group metal-containing catalyst may be a catalyst containing at least some nickel (Ni), at least some palladium (Pa), and / or at least some platinum (Pt).

[0045]

[0054] The first anode 28 is positioned to be in contact with a first gas stream 12 having a first hydrogen gas content 14 and a first impurity gas content 16. The relative content of the first hydrogen gas 14 and the first impurity gas content 16 in the first gas stream 12 is schematically shown in Figure 1 and other figures by a partial shading of an arrow identified as the first gas stream 12. This partial shading of the gas stream arrow 12 (and gas stream arrows 38 and 18 in Figure 1) is for illustrative purposes only and does not represent the actual relative gas content of these gas streams according to embodiments of the present invention.

[0046]

[0055] In one embodiment, a conductive gas diffusion layer (GDL), not shown in Figure 1, may be placed between the first gas flow 12 and the anode 28 to enhance the distribution of the first gas flow 12 around the surface of the anode 28. For example, the GDL may be applied to the surface of the anode 28 that is in contact with the first gas flow 12. In one embodiment, the GDL used in the cell 10, or the GDL layer used in any embodiment disclosed herein, may be a carbon fiber type GDL, for example, one provided by SGL Carbon GmBH, or an equivalent thereof. In another embodiment, gas distribution or flow field insert, with or without GDL A (as disclosed herein) can be placed on the anode 102 to facilitate or enhance the distribution of the first gas flow 12 across the surface of the anode 28.

[0047]

[0056] According to an aspect of the present invention, the catalyst contained in the first anode 28 is a hydrogen ion (H) according to formula 1, as is known in the art. + ) and electrons (e - To produce or generate ), the oxidation of at least hydrogen gas (H2) content 14 introduced into the anode 28 is promoted or enhanced. H2 => 2H + +2e - formula 1 Due to the permeability of anode 28, hydrogen gas (H2) enters anode 28, and due to the conductivity of anode 28, electrons (e -) is conducted from the anode 28, and according to an aspect of the present invention, hydrogen ions (H+) are introduced into the electrolyte 30. As is known in the art, hydrogen ion (H + ) is a proton. However, it is recognized in the art that at least some undesirable non-hydrogen gas 16 also passes through the anode 28.

[0048]

[0057] As is typical in the art, at least a portion of the input or first gas stream 12 does not need to be oxidized at the anode 28, and may be removed as a gas stream 13, for example, an "exhaust gas stream". Typically, due to the oxidation of hydrogen gas occurring within the first anode 28, the exhaust stream 13, which typically has a lower hydrogen gas content, is captured, directed for further processing through, for example, channels, manifolds, and ports, or may be disposed of as needed.

[0049]

[0058] The electrolyte 30 or the first electrolyte 30 is hydrogen ion (H + ) is arranged and adapted to receive and transfer at least a portion of the. Since the anode 28 is adjacent to the electrolyte 30, hydrogen ions (H + ) and non-hydrogen gas pass from the anode 28 to the electrolyte 30. The first electrolyte 30 includes a barrier between the first anode 28 and the electrode 32. The first electrolyte 30 is adapted to allow hydrogen ion (H +The electrolyte may include any material or substance that can transmit hydrogen ions (H+), i.e., protons, for example, from the first anode 28 to the electrode 32. That is, in one embodiment, the electrolyte 30 and any electrolyte disclosed herein may be referred to as a “proton-conducting material” while substantially preventing the flow of gases and electrons. The first electrolyte 30 and any electrolyte disclosed herein may typically be an acidic polymer containing an acid, for example, perfluorosulfonic acid (PFSA). In one embodiment, the electrolyte 30 and any electrolyte disclosed herein may be a membrane or equivalent commercially available under the trademark Nafion® by The Chemours Company in Wilmington, Delaware. In other embodiments, the electrolyte 30 and any electrolyte disclosed herein may contain any of the following acids, i.e., phosphoric acid [H3PO4], sulfuric acid [H2SO4], or any other hydrogen ions (H+). + ) may contain one or more conductive acids. In one embodiment, the first electrolyte 30 may include a proton exchange membrane (PEM), as is known in the art.

[0050]

[0059] As is known in the art, the passage of gas through electrolyte 30 and any electrolyte disclosed herein is driven, for example, by a partial pressure gradient of gas across the electrolyte from one side of electrolyte 30 to the other opposite side of electrolyte 30. Therefore, any undesirable non-hydrogen gas with a sufficient partial pressure gradient can also diffuse through electrolyte 30 and any electrolyte disclosed herein. In addition to pressure gradients across the electrolyte, defects in the electrolyte, such as small holes or voids in the electrolyte, can also undesirably allow gas to flow through electrolytes such as electrolyte 30.

[0051]

[0060] The electrode 32, sometimes referred to as the "cathode" 32 or first cathode 32 as is known in the art, is connected to hydrogen ions (H) transferred by the first electrolyte 30. +) is arranged to receive at least a portion of it. Similar to the first anode 28, the first Cathode 32 and any cathodes disclosed herein are typically, as known in the art, formed according to formula 2, with at least some electrons (e - By reacting with the first electrolyte 30, hydrogen ions (H) pass through the first electrolyte 30. + It contains a catalyst, such as a platinum group metal-containing catalyst, which is adapted to enhance at least some of the reactions (i.e., reductions) among the following. 2H + +2e - =>H2 formula 2

[0052]

[0061] The resulting or "generated" hydrogen gas (H2) 34, or second hydrogen gas content 34, and any non-hydrogen gas 36, or second impurity gas content 36, which are moved through the first cathode 32, are shown in Figure 1 as the gas flow 38, or second gas flow 38.

[0053]

[0062] In one embodiment, a gas diffusion layer (GDL) and / or flow field insert, not shown in Figure 1, may be placed between the first electrolyte 30 and the first cathode 32 to enhance the distribution of hydrogen gas around the surface of the first cathode 32. For example, the GDL and / or flow field insert may be applied to the surface of the first cathode 32.

[0054]

[0063] According to an aspect of the present invention, the second hydrogen gas content 34 is greater than the first hydrogen gas content 14, and the second impurity gas content 36 is less than the first impurity gas content 16.

[0055]

[0064] As shown in Figure 1, according to an embodiment of the present invention, a second gas stream 38 having a second hydrogen gas content 34 and a second impurity gas content 36 can then be introduced into a second MEA 26, specifically into the electrode 40 or second anode 40 of the second MEA 26. In the schematic diagram of the purifier cell 10 shown in Figure 1, the first MEA 24 is shown spaced apart from the second MEA 26 for the sake of illustrating and disclosing the present invention. However, according to an embodiment of the present invention, the space between the first MEA 24 and the second MEA 26 can be as small as, for example, the surface of the first cathode 32 can abut or contact the surface of the second anode 40. However, in one embodiment, there may be at least a small gap, for example, 0.1 millimeters [mm] to 0.5 mm, between the surface of the first cathode 32 and the surface of the second anode 40.

[0056]

[0065] According to an aspect of the present invention, in contrast to existing technologies, a second gas stream 38 having a second hydrogen gas content 34 and a second impurity gas content 36 can then be introduced into a second MEA 26 without removing or extracting the second gas stream 38 from the purifier cell 10. In other words, while some portion of the gas stream 38 may undesirably "escape" from the purifier cell 10, according to one aspect of the present invention, substantially all of the gas stream 38 generated at or diffused through the first cathode 32 is received by the second anode 40. For example, in one aspect, the second gas stream 38 can be allowed to pass from the first cathode 32 of the MEA 24 to the second anode 40 of the MEA 26 without any intervening handling or processing, for example, without passing outside the cell 10. In one embodiment, the generated hydrogen gas (H2) formed at the first cathode 32 can be oxidized substantially immediately to hydrogen ions (H+) at the second anode 40. In one embodiment, the second gas stream 38 can be passed directly from the first cathode 32 of the MEA 24 to the second anode 40 of the MEA 26 in the purifier cell 10, for example, without passing outside the cell 10 before reaching the second cathode 40.

[0057]

[0066] The second anode 40 is positioned to be in contact with a second gas flow 38 having a second hydrogen gas content 34 and a second impurity gas content 36. The second anode 40 of 6 may be similar to, if not identical to, the first anode 28 of MEA24. The second anode 40 may be permeable to hydrogen gas, and at least a portion of the hydrogen gas content 34 and at least a portion of the non-hydrogen gas content 36 in the second gas stream 38 may pass through the second anode 40 axially, for example, as indicated by the arrows in the second gas stream 38. Furthermore, the second anode 40 may be permeable to hydrogen gas hydrogen ions (H) as shown in Equation 1. + ) and electrons (e - The catalyst includes at least some catalysts, such as at least some platinum group metal-containing catalysts, which can enhance the oxidation to ).

[0058]

[0067] In one embodiment, a gas diffusion layer or GDL and / or flow field insert, not shown in Figure 1, may be placed between the first cathode 32 and the second anode 40 to enhance the distribution of the second gas flow 38 around the surface of the second anode 40. For example, the GDL and / or flow field insert may be applied to the surface of the second anode 40 that is in contact with the second gas flow 38.

[0059]

[0068] According to an aspect of the present invention, the catalyst contained in the second anode 40 promotes or enhances the oxidation of the hydrogen gas content 34 introduced into the second anode 40, thereby generating hydrogen ions (H) according to the above formula 1. + ) and electrons (e - ) produces or generates. In one embodiment, electrons (e) generated at the second anode 40 - The ) is directed back to the first cathode 32, as shown by arrow 41 in Figure 1, and according to Equation 2, hydrogen ions (H) are formed at the first cathode 32. + ) is used to reduce to hydrogen (H2) by electrons (e -At least a portion of ) can be supplied. Due to the permeability of the second anode 40, some impurity gases and any unoxidized hydrogen (H2) can pass through the second anode 40 and, according to aspects of the present invention, be introduced into or come into contact with the electrolyte 42.

[0060]

[0069] The electrolyte 42 of MEA26, or the second electrolyte 42, receives hydrogen ions (H) from the second anode 40. + The second electrolyte 42 is arranged and adapted to receive and transfer at least a portion of the first electrolyte 30. The second electrolyte 42 includes a gas barrier between the second anode 40 and the electrode 44. The second electrolyte 42 may be similar to the first electrolyte 30, if not substantially identical, and may contain any material or substance that can transfer hydrogen ions (H+), for example, hydrogen ions (H+), i.e., protons, from the second anode 40 to the electrode 44. In this case as with respect to the electrolyte 30, in one embodiment the electrolyte 42 may be referred to as a “proton-conducting material”. The second electrolyte 42 may typically be acidic and may contain, for example, one or more of the acids specified above with respect to the first electrolyte 30. However, in one embodiment the second electrolyte 42 may contain PEM, as is known in the art.

[0061]

[0070] Electrode 44, sometimes referred to as "cathode" 44 or second cathode 44 as is known in the art, is connected to hydrogen ions (H) transferred by the second electrolyte 42. + The second cathode 44 is typically arranged to receive at least some of the electrons (e) according to Equation 2 above. - ) using hydrogen ions (H +The electrolyte contains a catalyst adapted to enhance at least a portion of the reduction of the hydrogen gas (H2), such as a platinum group metal-containing catalyst. The hydrogen gas (H2) content 20, or third hydrogen gas content 20, and any non-hydrogen gas 22, or second impurity gas content 22, which have moved through the electrolyte 30, are shown in Figure 1 as the gas stream 18, or exhaust gas stream 18, or third gas stream 18.

[0062]

[0071] In one embodiment, hydrogen ions (H) around the surface of the second cathode 44 + To enhance the distribution of the electrolyte, a gas diffusion layer (GDL) and / or flow field insert, not shown in Figure 1, may be placed between the second electrolyte 42 and the second cathode 44, for example, the GDL and / or flow field insert on the surface of the second cathode 44. It may be applied.

[0063]

[0072] According to an embodiment of the present invention, the third hydrogen gas content 20 of the third gas stream 18 is greater than that of the first hydrogen gas content 14 and the second hydrogen gas content 34, and the third impurity gas content 22 is less than that of the first impurity gas content 16 and the second impurity gas content 36. However, typically, the third gas stream 18 may have a higher percentage purity than that of the first gas stream 12 on a "dry basis". For example, the third hydrogen gas content 20 in the third gas stream 18 may be at least 10 volume percent greater than that of the first hydrogen gas content 14 in the first gas stream 12. In one embodiment, the third hydrogen gas content 20 may be 20 to 30 volume percent greater than that of the first hydrogen gas content 14. Also, in one embodiment, the hydrogen in the third gas stream 18 may be at least 1,000 times purer by volume than that in the first gas stream 12. In one embodiment, the third gas stream 18 may be 10,000 to 10,000,000 [10 million] times purer in hydrogen by volume than the first gas stream 12. However, typically, the third gas stream 18 may be 100,000 to 2,000,000 [2 million] times purer in hydrogen by volume than the first gas stream 12. For example, in one embodiment, the purity of the third gas stream 18 may be at least 99.99 volume percent of hydrogen, or at least 99.999 (59) volume percent, or 99.9999 (69) volume percent. According to another embodiment of the present invention, the purity of the third gas stream 18 can be expressed based on the content of a third impurity gas 22. For example, in one embodiment, the content of the third impurity gas 22 may be up to 100 ppm of impurity gas. In other aspects of the present invention, the content 22 of the generated third impurity gas may be up to 20 ppm, or up to 10 ppm, up to 5 ppm, or up to 2 ppm, or up to 1 ppm. In other aspects of the present invention, the content 22 of the generated third impurity gas in the generated hydrogen gas 18 may be up to 750 ppb (i.e., up to 0.750 ppm), or up to 500 ppb, or up to 200 ppb, or even up to 100 ppb. As is known in the art, these impurity content values ​​of the generated hydrogen gas are typically on a "dry basis".

[0064]

[0073] According to aspects of the present invention, by passing a second gas stream 38 having a hydrogen gas content 34 through the first cathode 32 of the MEA 24 to the second anode 40 of the second MEA 26 in the purifier cell 10, it is possible to provide not only a more compact purifier but also a more efficient device and a purer hydrogen gas content 22 than in the prior art. In particular, the passage of the second gas stream 38 from the first cathode 32 to the second anode 40 avoids, for example, the addition of recognized components, loss of efficiency, and loss of hydrogen gas content that directly characterize the performance of the prior art hydrogen gas purifier.

[0065]

[0074] In addition, according to aspects of the present invention, the resulting gas flow, i.e., the third gas flow 18 having a higher hydrogen gas content 20, can typically be supplied at a pressure higher than the supply or the pressure of the first gas flow 12. For example, according to aspects of the present invention, if the first gas flow 12 may have a pressure of about 1 pound / square inch-gauge [psig], the third gas flow 18 may have a pressure of at least 150 psig. In one aspect, the pressure of the third gas flow 18 may be at least 120 psig, or at least 200 psig, or even at least 10,000 psig [10,000]. In other aspects of the present invention, the pressure of the third gas flow 18 may be less than or equal to the pressure of the supply or the first gas flow 12, and in one aspect, the pressure of the third gas flow 18 may be less than the pressure of the first gas flow 12.

[0066]

[0075] Figure 2 is a schematic diagram of a hydrogen gas purifier cell 50 according to another embodiment of the present invention. According to this embodiment, the purifier cell 50 may have many of the features of the purifier cell 10, but the purifier cell 50 further includes at least one gas outlet or discharge section between the MEAs. According to this embodiment, the test involves supplying at least a portion of the second gas flow (38 in Figure 2) to the purifier cell It has been shown that venting or releasing from 50 results in a higher hydrogen gas content compared to a purifier that does not allow the removal of at least a portion of the second gas flow between the MEAs. This venting of at least a portion of the second gas flow is thought to reduce the partial pressure of non-hydrogen gas between the MEAs and thus reduce the partial pressure gradient driving force of undesirable non-hydrogen gas passing through the second MEA. In a further embodiment, since a portion of the desired hydrogen gas is lost when a portion of the second gas flow is removed, at least a portion of the hydrogen gas can be introduced between the MEAs to act as "replenishment" hydrogen gas for the hydrogen gas that may be lost with the removal of a portion of the second gas flow.

[0067]

[0076] As shown in Figure 2, in a manner similar to that of the purifier cell 10, the purifier cell 50 is configured and adapted to receive the same or identical supply as the first gas flow 12 shown in Figure 1, or the first gas flow 12, and at least some non-hydrogen gas 16, and to produce a gas flow 52 with an increased hydrogen gas content and a reduced non-hydrogen gas content. The gas flow 52 may be referred to as the exhaust gas flow 52 or the third gas flow 52. Similar to the purifier cell 10, the third gas flow 52 may typically include an enhanced hydrogen gas content 54 and a reduced non-hydrogen gas content 56. Similar to the purifier cell 10, the hydrogen gas purifier cell 50 typically comprises a multilayer structure having components, for example, anodes and cathodes having thin planar or thin layered structures, and the structure shown in Figure 2 may include a side view or axial cross section of the purifier cell 50, which is not drawn to scale but is drawn to facilitate the disclosure of the present invention.

[0068]

[0077] In one embodiment, the hydrogen gas purifier cell 50 shown in Figure 2 may have a first MEA 24 substantially identical to that of the purifier cell 10, namely having a first anode 28, a first electrolyte 30, and a first cathode 32, and purifying the first gas stream 12 at least partially in substantially the same manner as the purifier cell 10 shown in Figure 1, to produce a second gas stream 38 having a hydrogen gas content 34 and a non-hydrogen gas content 36. As is typical in the art, the input or at least a portion of the first gas stream 12 may not diffuse through the anode 28 and may be removed as a gas stream 13, for example, an "exhaust gas stream". Furthermore, the hydrogen gas purifier cell 50 may have a second MEA 26 substantially identical to that of the purifier cell 10, having a second anode 40, a second electrolyte 42, and a second cathode 44, to purify the gas stream 38 at least partially to obtain a third gas stream 52 having a hydrogen gas content 54 and a non-hydrogen gas content 56. However, according to the embodiment of the present invention shown in Figure 2, the hydrogen gas purifier cell 50 includes at least one exhaust gas stream or replacement gas stream 58 having a non-hydrogen gas content 60 and a hydrogen gas content 62. It is recognized that the non-hydrogen gas content 60 and hydrogen gas content 62 of the exhaust gas stream 58 may be substantially the same as the non-hydrogen gas content 36 and hydrogen gas content 34 of the second gas stream 38.

[0069]

[0078] In one embodiment, one or more gas diffusion layers (GDLs) and / or flow field inserts, not shown in Figure 2, can be placed within the cell 50 to enhance the distribution of gas flow around the electrode surface. For example, the cell 50 may include GDLs and / or flow field inserts associated with the first anode 28, the first cathode 32, the second anode 40, and / or the second cathode 44.

[0070]

[0079] According to this embodiment, the first gas stream 12 is treated by the first MEA 24 to produce a second gas stream 38 having a hydrogen gas content 34 and a non-hydrogen gas content 36, after which at least a portion of the gas stream 38 is removed via gas stream 58. The removal of gas stream 58 from gas stream 38 results in a reformed or intermediate gas stream 64 having a hydrogen gas content 66 and a non-hydrogen gas content 68. It is recognized that the non-hydrogen gas content 68 and hydrogen gas content 66 of the reformed gas stream 64 may be substantially the same as the non-hydrogen gas content 36 and hydrogen gas content 34 of the second gas stream 38. According to an embodiment of the present invention, the removal of gas stream 58 results in a reformed gas This reduces the partial pressure of the non-hydrogen gas content 68 in flow 64, and this reduction in partial pressure reduces the partial pressure gradient of the non-hydrogen gas content 58 across the second MEA 26, which reduces the passage of the non-hydrogen gas content 68 through the second MEA 26 to the third gas flow 52. Therefore, according to an embodiment of the present invention, the non-hydrogen gas content 56 in the third gas flow 52 is reduced.

[0071]

[0080] The removal of the gas flow 58 having a non-hydrogen content 60 can be carried out by various means. In one embodiment, the gas flow 58 can be removed by simply exhausting at least a portion of the second gas flow 38, for example, through the inherent gap between the first MEA 24 and the second MEA 26, for example, through the inherent space or gap between the surface of the first cathode 32 and the second anode 40. In another embodiment, the gas flow 58 can be removed by providing a path, channel, or groove, for example, a radial or transverse channel or groove, in the mating surface of the first cathode 32, the mating surface of the second anode 40, or both the mating surfaces of the first cathode 32 and the second anode 40. In yet another embodiment, the gas flow 58 may be removed through a GDL and / or flow field insert positioned between the mating surface of the first cathode 32 and the mating surface of the second anode 40. As is known in the art, the gas flow (GDL) is typically a porous material such as carbon paper through which a gas flow 58 can pass. In another embodiment, the gas flow 58 may be removed by providing a path for the gas flow 58 by providing one or more spacers between the mating surface of the first cathode 32 and the mating surface of the second anode 40. In one embodiment, a vacuum source may be introduced to draw out at least a portion of the second gas flow 38 through the gas flow 58.

[0072]

[0081] According to another aspect of the present invention, after the first gas stream 12 is treated by the first MEA 24 to produce a second gas stream 38 having a hydrogen gas content 34 and a non-hydrogen gas content 36, at least some of the hydrogen gas can be introduced into the gas stream 38. As shown in Figure 2, in one aspect, the hydrogen gas can be introduced into the second gas stream 38 via a gas stream 59 (shown by dashed lines in Figure 2) to replace the hydrogen gas 62 lost from the second gas stream 38 via the gas stream 58 and produce a reformed gas stream 64. In one aspect, the gas stream 38 may be, for example, a high-purity hydrogen gas having at least a higher purity than the hydrogen content 14 of the first gas stream 12, but in other aspects, the gas stream 59 may be a hydrogen gas-containing stream having at least some of the hydrogen gas content, or it may have a non-hydrogen gas content.

[0073]

[0082] The introduction of a hydrogen-containing gas flow 59, for example, a "supplementary gas flow," may be carried out with or without the removal of the gas flow 58. The introduction of the gas flow 59 into the gas flow 38 may be carried out in any one or more convenient ways, for example, by introducing the hydrogen-containing gas flow 59 through a gas-permeable electrolyte 42 driven by a hydrogen gas partial pressure gradient, or through a gas-permeable first cathode 32, through a gas-permeable GDL and / or flow field insert, or through a channel in the first cathode 32, a channel in the second anode 40, or through channels in both the first cathode 32 and the second anode 40. Any channels that can be provided for the hydrogen-containing gas flow 59 may be located on one or both of the opposing surfaces of the first cathode 32 and the second anode 40, i.e., the surfaces of the space occupied by the second gas flow 38. In one embodiment, the supplementary hydrogen gas flow 59 may include at least a portion of the third gas flow 52 having a third hydrogen content 54. For example, at least a portion of the third gas flow 52 may be introduced into the second gas flow 38 by diffusion through the second electrolyte 42, as shown by the dashed line by gas flow 59A in Figure 2. This diffusion through the second electrolyte 42 may be referred to as "reverse diffusion" of at least a portion of the third gas flow 52 having a third hydrogen content 54 through the second electrolyte 42, for supplying at least a portion of the replenishment gas flow 59 to the second gas flow 38 or the reformed gas flow 64. The replenishment gas flow 59 may provide any one or more of these mechanisms.

[0074]

[0083] According to an aspect of the present invention, the third hydrogen gas content 54 of the third gas stream 52 is greater than that of the first hydrogen gas content 14 and the second hydrogen gas content 34, and the third impurity gas content 56 is less than that of the first impurity gas content 16 and the second impurity gas content 36. However, typically, the third gas stream 52 can have a higher percentage purity than that of the first gas stream 12 on a "dry basis". For example, in one aspect, the purity of the third hydrogen gas content 54 may be at least 99.99 volume percent, or at least 99.999 (five nines) volume percent, or 99.9999 (six nines) volume percent. According to another aspect of the present invention, the purity of the third gas stream 52 can be expressed based on the third impurity gas content 56. For example, in one aspect, the third impurity gas content 56 may be up to 100 ppm of impurity gas. In other aspects of the present invention, the content of the third impurity gas 56 produced may be up to 20 ppm, or up to 10 ppm, or up to 5 ppm, or up to 2 ppm, or up to 1 ppm. In other aspects of the present invention, the content of the third impurity gas 56 in the produced hydrogen gas may be up to 750 ppb (i.e., up to 0.750 ppm), or up to 500 ppb, or up to 200 ppb, or even up to 100 ppb. As is known in the art, these impurity content values ​​in the produced hydrogen gas are typically on a "dry basis".

[0075]

[0084] Figure 3 is a schematic front view of a hydrogen gas purifier stack assembly 80 having a hydrogen gas purifier cell 82, for example, a hydrogen gas purifier cell 10 or cell 50 disclosed herein, arranged between opposing conductive but gas-impermeable layers or plates 84 and 86 and conductive layers or busbars 88 and 90, according to one aspect of the present invention. The conductive but gas-impermeable layers or plates 84 and 86 may be referred to as “bipolar plates,” as is known in the art, since the plates 84 and 86 may typically contain passages or channels adapted to introduce or remove gas from the cell 82. The conductive layers or busbars 88 and 90 may also be referred to as “current collectors.” As shown, in one aspect, the cell 82 may include at least two MEAs, a first MEA92 and at least a second MEA94. However, according to aspects of the present invention, it is envisioned that cell 82 may include, for example, three or more MEA92,94, or five or more MEA92,94, arranged between busbars 88 and 90. In one embodiment, at least 10 MEA92,94 may be arranged between busbars 88 and 90.

[0076]

[0085] In one embodiment, the hydrogen gas purifier cell 82 may be referred to as a "double membrane electrode assembly" or "DMEA". The first MEA 92 includes a first anode 96, a first electrolyte 98, and a first cathode 90. The first anode 96 may be the same as, if not identical to, the first anode 28 disclosed herein, the first electrolyte 98 may be the same as, if not identical to, the first electrolyte 30 disclosed herein, and the first cathode 90 may be the same as, if not identical to, the first cathode 32 disclosed herein. The second MEA 94 includes a second anode 102, a second electrolyte 104, and a second cathode 106. The second anode 102 may be the same as, if not identical to, the second anode 40 disclosed herein, the second electrolyte 104 may be the same as, if not identical to, the second electrolyte 42 disclosed herein, and the second cathode 106 may be the same as, if not identical to, the second cathode 44 disclosed herein.

[0077]

[0086] The conductive, gas-impermeable layers or plates (or bipolar plates) 84 and 86 can typically be produced from a corrosion-resistant or non-oxidizing material for the electrochemistry of cell 82. While any conductive, substantially gas-impermeable, and substantially corrosion-resistant material, such as a metal, may be used for plates 84 and 86 in embodiments of the present invention, typically plates 84 and 86 can be made from a conductive, substantially gas-impermeable, and substantially corrosion-resistant graphite-containing material. For example, plates 84 and 86 may be made from graphite... They can be made from materials containing powders and resins. In one embodiment, the bipolar plates 84 and 86 may be made from a nonmetallic material, such as plastic, in which conductive inserts and / or particles are arranged to provide the desired conductivity.

[0078]

[0087] In one embodiment, the bipolar plates 84 and 86 may include at least semi-permeable portions to allow fluid permeability as needed for, for example, thermal and / or water management.

[0079]

[0088] According to one aspect of the present invention, the conductive current collectors 88 and 90 can have relatively high conductivity to, for example, plates 84 and 86. In one aspect, the current collectors 88 and 90 may be plated, for example, with gold or silver, to improve conductivity. For example, the current collectors 88 and 90 may include stainless steel plates, aluminum plates, or copper plates that can be plated with gold or silver.

[0080]

[0089] According to an aspect of the present invention, as shown in Figure 3, the first gas stream 108 containing hydrogen gas (H2) and a non-hydrogen gas may be introduced to the first anode 96 as disclosed herein, where at least a portion of the hydrogen gas (H2) is converted into hydrogen ions (H2) according to formula 1. +) and electrons (e-) are oxidized. The first gas flow 108 may be introduced to the first anode 96 by any conventional means, for example, through passages and / or channels in the bipolar plate 84. For example, as shown in Figure 3, the first gas flow 108 may be introduced to the first anode 96 through a plurality of transverse passages 110 communicating with a plurality of longitudinal passages or channels 112 that discharge onto the first anode 96. The first anode 96 may include GDLs and / or flow field inserts (not shown in Figure 3), such as carbon paper type GDLs, to enhance the distribution of the first gas flow 108 across the surface of the first anode 96.

[0081]

[0090] Upon introduction to anode 96, the reaction and fluid flow described with respect to Figures 1 and 2 are generated within MEA 92 and 94, specifically, according to embodiments of the present invention, a second gas flow 114 from the first cathode 100 (not shown in Figure 3) and a third gas flow 116 from the second cathode 106 are generated. As disclosed herein, the second anode 102 receives the second gas flow 114 (again, not shown in Figure 3). In one embodiment, the second anode 102 may include, or be accompanied by, a GDL and / or flow field insert (not shown in Figure 3), e.g., a carbon paper type GDL, to enhance the distribution of the second gas flow 114 across the surface of the second anode 102. The third gas flow 116 can be collected from the second cathode 106 by conventional means. For example, as shown in Figure 3, the third gas flow 116 may be removed from the second cathode 106 through a gas diffusion layer (not shown) or without passing through a gas diffusion layer (not shown) via a plurality of longitudinal passages or a plurality of transverse passages 118 communicating with a channel 120 that are in fluid communication with the second cathode 106. The plurality of transverse passages 118 may include a plurality of substantially parallel passages or a plurality of meandering passages within the bipolar plate 86. As is known in the art, the parallel or meandering passages within the bipolar plate 86 may be in fluid communication with one or more manifolds, for example, vertical or longitudinal manifolds, and the one or more manifolds may be in fluid communication with one or more ports for introducing, discharging, or redirecting the gas flow.

[0082]

[0091] According to aspects of the present invention, the third gas stream 116 may contain a higher hydrogen gas (H2) content and a lower non-hydrogen gas content than the first gas stream 108. For example, as disclosed herein, the non-hydrogen gas content of the third gas stream 116 may be up to 100 ppm, or up to 20 ppm, or up to 10 ppm, or up to 500 ppb of non-hydrogen gas "on a dry basis". In addition, the third gas stream 116 is typically the same as the first gas stream 108. In other embodiments, the third gas flow 116 may have a pressure higher than that of the first gas flow 108, although in other embodiments, the third gas flow 116 may have a pressure lower than that of the first gas flow 108.

[0083]

[0092] Figure 3A shows a schematic detail view of the interface between the first cathode 100 and the second anode 102 according to one aspect of the present invention. Figure 3A is a detail view of a part of the hydrogen purifier stack assembly 80 shown in Figure 3, as identified by detail 3A shown in Figure 3. As shown in Figure 3A, the second gas stream 114 having a hydrogen gas content 34 (see Figures 1 and 2) and a non-hydrogen gas content 36 exits the first cathode 100 and enters the space 101 between the mating surfaces of the first cathode 100 and the second anode 102. Between the first cathode 100 and the second anode 102, there is typically a space, void, or gap space 101 due to imperfections in the mating surfaces of the first cathode 100 and the second anode 102, and in particular due to imperfections and / or tolerances in production. These spaces or gaps 101 may be minute, but are typically located between the mating surfaces of the first cathode 100 and the second anode 102 and other mating electrodes disclosed herein, and are thought to provide a path for a gas flow, e.g., for the removal and / or introduction of a gas flow. According to embodiments of the present invention, the second gas flow 114 enters typically in contact with the second anode 102, either through direct contact or through the spaces 101, where catalytic oxidation of the hydrogen gas content 34 in the second gas flow 114 occurs, according to embodiments of the present invention described herein. In one embodiment, as shown in Figure 3B, a GDL 105 can be placed between the first cathode 100 and the second anode 102 to facilitate or enhance the distribution of the second gas flow 114 across the surface of the second anode 102. In another embodiment, to facilitate or enhance the distribution of the second gas flow 114 across the surface of the second anode 102, a gas distribution or flow field insert having or not having a GDL, as shown by GDL 105 in Figure 3B, may be placed between the first cathode 100 and the second anode 102 (or between any electrodes disclosed herein). The flow field insert may be a conductive, porous, or perforated plate, e.g., a porous or perforated metal plate, or a screen-like insert, e.g., a metal screen-like insert, arranged and adapted to provide at least some gas distribution around the surface of the second anode 102.Flow field inserts disclosed herein may also include channels or passages for enabling the introduction or removal of gas flow from or to adjacent electrodes.

[0084]

[0093] As disclosed herein, the gas purifier cell 82 may comprise the hydrogen gas purifier cell 10 disclosed and described with respect to Figure 1, or the hydrogen gas purifier cell 50 disclosed and described with respect to Figure 2. Detailed drawings shown in Figures 3A and 3B also illustrate these aspects of the present invention. Specifically, if the gas purifier cell 82 of Figure 3 comprises the purifier cell 10 as shown in Figure 3A, substantially all of the second gas flow 114 leaving the first cathode 100 passes to the second anode 102 (with or without GDL 105 and / or flow field insert) through direct contact or through space 101 for subsequent catalytic oxidation, as disclosed herein, for example, through direct contact.

[0085]

[0094] In an embodiment of the present invention in which the gas purifier cell 82 in Figure 3 includes the purifier cell 50, at least a portion of the second gas stream 114 leaving the first cathode 100 is removed as gas stream 58 (see Figure 2), as shown in Figures 3A and 3B. In this embodiment, the removed gas stream 58 may contain at least a portion of non-hydrogen gas, and once removed, the remaining reformed gas stream has a lower partial pressure relative to the non-hydrogen gas. The lower partial pressure of the non-hydrogen gas is less likely to be transmitted through the second electrolyte 104 to the output or third gas stream 116 (see Figure 3). As shown in Figure 3A, the removed or exhausted gas stream 58 may be passed through space 101, and / or, as shown in Figure 3B, the removed or exhausted gas stream 58 may be passed through GDL 105 and / or flow field inserts.

[0086]

[0095] Furthermore, as shown in Figures 3A and 3B, in one embodiment, a hydrogen-containing gas stream 59 (shown by dashed lines in Figures 3A and 3B) and / or 59A may also be introduced into the second gas stream 114, with or without the removal of gas stream 58. For example, as disclosed herein, the hydrogen-containing gas streams 59 and / or 59A may be provided to enhance the hydrogen gas content of the second gas stream 114 introduced into the second anode 102, for example, to enhance the hydrogen content in a third gas stream 116 (see Figure 3), i.e., the output stream 116, and / or to replace at least a portion of the hydrogen gas content removed in gas stream 58. As shown in Figures 3A and 3B, the introduction of the hydrogen-containing gas stream 59 and / or 59A into space 101 may be carried out together with or in the presence of the GDL 105, for example, as shown in Figure 3B, the hydrogen-containing gas stream 59 may be introduced through the gas-permeable GDL 105 and / or flow field insert.

[0087]

[0096] Figure 4 is a schematic front view of a hydrogen purifier stack 130 having a plurality of hydrogen purifier cells 132A to 132N, for example, two or more hydrogen purifier cells 10 as shown in Figure 1 and / or two or more hydrogen cells 50 as shown in Figure 2, according to one aspect of the present invention. According to an aspect of the present invention, "N" is the number of purifier cells that may be included in the hydrogen purifier stack 130 according to an aspect of the present invention. Specifically, N may range from 1 to 1,000 cells, but is typically assumed to be in the range of 40 to 100 cells, for example, 80 cells.

[0088]

[0097] According to this aspect of the present invention, each of the hydrogen purifier cells 132A to 132N includes a double MEA (DMEA) separated by a conductive and gas-impermeable layer or plate 134A to 134N+1, for example, a “bipolar plate,” as disclosed herein. The layer or plate 134A to 134N+1 is similar to and can have the same properties as the layers or plates 84 and 86 illustrated and described with respect to Figure 3. For example, the layer or plate 134A to 134N+1 may have one or more lateral passages and a plurality of axial passages or channels, for example, flow distribution passages, adapted and positioned to introduce a gas flow into and / or remove a gas flow from the hydrogen purifier cells 132A to 132N. According to aspects of the present invention, some plates 134A to 134N+1, for example, plate 134B shown in Figure 4, may include passages, such as isolated separate passages, adapted and located to both remove gas flow from the second cathode of DMEA 132A and introduce gas flow from the first anode of DMEA 132B. In contrast, terminal plate 134A may include a passage adapted and located to introduce gas flow only to the first anode of DMEA 132A, and terminal plate 134N+1 may include a passage adapted and located to remove gas flow only from the second cathode of DMEA 132N. In one embodiment, terminal plates 134A and / or terminal plates 134N+1 may not have passages; that is, they may lack passages.

[0089]

[0098] According to aspects of the present invention, as disclosed herein, the reduction reaction related to the cathode according to formula 2 is performed according to formula 1, for example, the electrons (e) for the oxidation reaction related to the previous or previous anode in the stack. - ) can be provided. In one embodiment, electrons (e) in the hydrogen purifier stack 130 -This flow is such that the DMEAs of the hydrogen purifier stack 130 are electrically in series. However, to facilitate the illustration and disclosure of this aspect of the present invention, for example, electrons (e) from the second anode to the first cathode of adjacent cells in the hydrogen purifier stack 130. - ) flow, and electrons (e) from the first anode to the second cathode - The flow of ) is omitted from Figure 4.

[0090]

[0099] The hydrogen purifier stack 130 also includes opposing busbars or current collectors 136 and 138, and end plates 137 and 139 (shown by dashed lines in Figure 4). Current collectors 136 and 138 are shown with respect to Figure 3 and may be similar in design, size, and structure to current collectors 88 and 90 disclosed. End plates 137 and 139 may be relatively thick metal plates that function to assist in compressing the stack 130, for example, via a plurality of mechanical fasteners (not shown) extending between end plates 137 and 139, as is known in the art. For example, end plates 137 and 139 may be associated with a plurality of threaded bolts having threaded nuts that, when the bolts are tightened, compress the stack 130 between plates 137 and 139.

[0091]

[0100] As shown in Figure 4, it has hydrogen gas (H2) content and non-hydrogen gas content. Multiple inputs or first gas flows 140A-140N can be introduced into DMEA 132A-132N via inlets and flow distribution passages within plates 134A-134N. As shown in Figure 4, the first gas flows 140A-140N can be supplied, for example, via one or more gas supply manifolds 141 (shown by dashed lines in Figure 4), such as a common gas supply manifold. Also, as shown in Figure 4, multiple discharges or third gas flows 142A-142N can be removed from DMEA 132A-132N, for example, via flow extraction passages and outlets within plates 134A-134N. As shown in Figure 4, the third gas flows 142A-142N can be discharged, for example, via one or more gas collection manifolds 143 (shown by dashed lines in Figure 4), such as a common gas collection manifold. As disclosed herein, each of the multiple outputs or third gas flows 142A to 142N has a higher hydrogen gas (H2) content and a lower non-hydrogen gas content than the multiple input gas flows 140A to 140N. For example, as disclosed herein, the non-hydrogen gas content of the third gas flows 142A to 142N may be up to 100 ppm, or up to 20 ppm, or up to 10 ppm, or up to 5 ppm, or up to 2 ppm, or up to 1 ppm "on a dry basis", or even up to 500 ppb "on a dry basis", or even up to 500 ppb "on a dry basis". According to aspects of the present invention, each of the gas flow flows from input flows 140A to 140N to output flows 142A to 142N may flow in parallel through DMEA 132A to 132N, for example, from one or more gas supply manifolds 141 to one or more gas collection manifolds 143.

[0092]

[0101] Although not shown in Figure 4 for the sake of facilitating the illustration and disclosure of the present invention, In an apparent embodiment, the hydrogen purifier stack 130 may typically include a plurality of anode exhaust ports, passages, and / or manifolds to allow excess source gas from flows 140A to 140N to be discharged from the hydrogen purifier stack 130.

[0093]

[0102] Furthermore, as shown in Figure 4, the hydrogen purifier stack 130 has a current collector 13 The stack 130 can be powered by a voltage ΔV and a current I between 6 and 138. The voltage ΔV may be supplied from an external source, for example, from one or more DC power sources, a local power grid, a fuel cell, solar power, and / or a wind turbine, and / or from an internal source, for example, from the electrochemical potential and reactions occurring in DMEA 132A~132N within the stack 130. In one embodiment, the voltage ΔV can be adjusted to adjust the current flowing through the stack 130. A higher current can enhance the chemical reactions within the stack 130 and increase the hydrogen gas production rate. The amount of amperage required to improve the output of the embodiments of the present invention depends, among other things, on the size of the purifier and the number of cells in the purifier.

[0094]

[0103] As shown in Figure 4, according to one aspect of the present invention, the hydrogen purifier stack 130 One or more of the DMEA132A~132N may include the purifier cell 50 shown and described with respect to Figure 2. That is, in one embodiment, one or more of the DMEA132A~132N, for example, all of the DMEA132A~132N, may include at least a portion of the gas flow generated from the first cathode of the DMEA132A~132N, for example, the second gas shown in Figure 2. It may be adapted to remove flow 38. This removal of at least a portion of the gas flow from the second gas flow of DMEA 132A-132N is shown by gas flow 144A-144N (shown by dashed lines) in Figure 4. Gas flow 144A-144N in Figure 4 corresponds to gas flow 58 in Figure 2. As disclosed herein, according to one aspect of the present invention, it is understood that the removal of gas flow 144A-144N having at least a portion of the non-hydrogen gas content reduces the partial pressure of the non-hydrogen gas introduced into the second anode of DMEA 132A-132N, and therefore reduces the passage of non-hydrogen gas through the second anode. According to one aspect, gas flow 144A-144N may be discharged from the hydrogen purifier stack 130 via an exhaust passage in the hydrogen purifier stack 130, for example, an exhaust gas manifold (not shown in Figure 4).

[0095]

[0104] In addition, some of the gas flow lines 144A~144N (dashed lines) in Figure 4 are Because it may contain a portion of hydrogen gas, in one embodiment, at least a portion of the hydrogen gas can be introduced into a second gas flow in DMEA 132A-132N (i.e., a second gas flow 38 shown in Figure 2) to replenish at least a portion of the lost hydrogen gas and improve the hydrogen gas content introduced into the second anode of DMEA 132A-132N. By replenishing any lost hydrogen gas via gas flow 144A-144N, embodiments of the present invention can improve the hydrogen content of the hydrogen gas produced by the hydrogen purifier stack 130. This introduction of at least a portion of the hydrogen gas into the second gas flow of DMEA 132A-132N is shown by gas flows 146A-146N (dummy lines) in Figure 4. According to one embodiment, gas flows 146A-146N can be introduced into the hydrogen purifier stack 130 via a passage in the hydrogen purifier stack 130, for example, a gas manifold (not shown in Figure 4).

[0096]

[0105] Figure 5 is a schematic diagram of a hydrogen gas purification cell 150 according to a further embodiment of the present invention. In this embodiment, the purifier cell 150 may have many of the features of the purifier cell 10 and purifier cell 50 disclosed herein. Specifically, the purifier cell 150 includes a DMEA 152, which is configured to receive an input or a first gas flow 154 having a first hydrogen gas content 156 and a first non-hydrogen gas content 158, and yields an output or a third gas flow 160 having an output greater than the first hydrogen gas content 156 or an output less than the third hydrogen gas content 162 and the first non-hydrogen gas content 158 ​​or a third non-hydrogen gas content 164. As is typical in the art, at least a portion of the input or first gas flow 154 may not be oxidized at the anode 166, but may be removed as a gas flow 155, e.g., an "exhaust gas flow". Typically, the exhaust gas flow 155 may be captured and directed to further processing, or disposed of as needed, for example, through channels, manifolds, and ports.

[0097]

[0106] Again, the output or third gas flow 160 is typically the input or first gas flow The pressure will be greater than that of 154, but the pressure may be lower than that of the first gas flow 154. However, according to this aspect of the present invention, the DMEA 152 of the purifier cell 150 comprises only three electrodes, the second electrode performing a dual function as both the first cathode and the second anode, as disclosed herein.

[0098]

[0107] Specifically, as shown in Figure 5, DMEA152 of the purifier cell 150 is It comprises an anode 166, a first electrolyte 168, a first cathode / second anode (or “dual electrode”) 170, a second electrolyte 172, and a second cathode 174. Similar to the components and operation of cells 10 and 50 disclosed herein, the first anode 166 may have all the features of the first anode disclosed herein, the first electrolyte 168 and the second electrolyte 172 may have all the features of the electrolyte disclosed herein, and the second cathode 174 may have all the features of the second cathode disclosed herein. That's good too.

[0099]

[0108] In addition, the dual electrode 170 of cell 150 is an anode or as disclosed herein. The cathode may have all the characteristics and properties of a cathode, for example, being conductive, gas permeable, and containing a catalyst. However, according to this aspect of the present invention, the double electrode 170 first receives hydrogen ions (H) that have moved through the first electrolyte 168 according to formula 2. + ) to electrons (e - ) is reduced to produce hydrogen gas (H2), and then, according to Equation 1, the hydrogen gas (H2) is oxidized to produce hydrogen ions (H + ) and electrons (e - It performs a dual function of generating electrons (e) in the oxidation of hydrogen gas (H2) within the double electrode 170. - ) is hydrogen ions (H) in the double electrode 170.+ The electrons (e) consumed in the reduction of ) - ) may be a source of electrons (e) in the double electrode 170 in DMEA152. - This internal movement of ) is represented by an electron loop 176, shown by a dashed line in Figure 5. According to an aspect of the present invention, one or more cells 150 can be used in cells 132A to 132N of the stack 130 shown in Figure 4.

[0100]

[0109] According to one aspect of the present invention, the exhaust gas flow (gas flow 58 in Figure 2) is in cell 150 The gas stream 178 may be removed from the double electrode 170, and / or a supplement gas stream (gas streams 59 and / or 59A in Figure 2) may be introduced into the double electrode 170. As shown in Figure 5, the gas stream 178 may be removed from the double electrode 170, for example, through the gas permeable structure of the double electrode 170, and may reduce the partial pressure of non-hydrogen gas passing through the first electrode 168, as disclosed herein. Also, with or without the removal of the gas stream 178, a supplement hydrogen (H2) gas-containing gas stream 180 (shown by dashed lines in Figure 5) may be introduced into the double electrode 170, for example, through the gas permeable structure of the double electrode 170, in order to replace or enhance the hydrogen gas (H2) content of the gas stream introduced into the second electrolyte 172, as disclosed herein. Similar to other aspects of the present invention, the supplement hydrogen (H2) gas-containing gas stream 180 can be introduced into the double electrode 170 by "back diffusion," in which at least a portion of the gas stream 160 returns to the double electrode 170 through the second electrode 172.

[0101]

[0110] In one embodiment, the gas flow around the electrode surface and / or hydrogen ions (H + ) distribution To enhance this, one or more gas diffusion layers (GDLs) not shown in Figure 5, and / or flow field inserts as described with respect to Figure 3B, can be placed within cell 150. For example, cell 150 may include GDLs and / or flow field inserts associated with a first anode 166, a dual electrode 170, and / or a second cathode 174.

[0102]

[0111] As in other aspects of the present invention, only the three electrodes 166, 170, and 174 are used. However, the third hydrogen gas content 162 of the third gas stream 160 of the hydrogen purifier cell 150 is greater than the first hydrogen gas content 156, and the third impurity gas content 164 is less than the first impurity gas content 158. For example, the third gas stream 160 can have a higher percentage purity than the purity of the first hydrogen gas content 156 of the first gas stream 154 on a "dry basis". For example, in one embodiment, the purity of the third gas stream 160 may be at least 99.99 volume percent of hydrogen, or at least 99.999 (59) volume percent, or 99.9999 (69) volume percent. According to another embodiment of the present invention, the purity of the third gas stream 160 may be expressed based on the third impurity gas content 164. For example, in one embodiment, the third impurity gas content 164 may be up to 100 ppm of impurity gas. In another aspect of the present invention, the content of the third impurity gas 164 produced may be up to 20 ppm, or up to 10 ppm, or up to 5 ppm, or up to 2 ppm, or up to 1 ppm. In another aspect of the present invention, the content of the third impurity gas 164 in the produced hydrogen gas may be up to 750 ppb (i.e., up to 0.750 ppm), or up to 500 ppb, or up to 200 ppb, or even up to 100 ppm. It may also be pb. As is known in the art, the content of these impurities in the generated hydrogen gas is typically on a "dry basis".

[0103]

[0112] In addition, according to an aspect of the present invention, the resulting gas flow, i.e., higher hydrogen The third gas stream 160 in Figure 5, having a gas content 162 and a lower impurity gas content 164, can typically be supplied at a pressure higher than the supply or the pressure of the first gas stream 154. For example, according to an aspect of the present invention, if the first gas stream 154 can have a maximum pressure of 1 psig, the third gas stream 160 can have a pressure of at least 150 psig. In one aspect, the pressure of the third gas stream 160 may be at least 120 psig, or at least 200 psig, or even at least 10,000 psig. In another aspect of the present invention, the pressure of the third gas stream 160 may be less than or equal to the pressure of the supply or the first gas stream 154, and in one aspect, the pressure of the third gas stream 160 may be less than the pressure of the first gas stream 154.

[0104]

[0113] Figure 6 shows one or more hydrogen purifiers shown in Figure 4 according to one aspect of the present invention. This is a schematic diagram of a hydrogen gas purification system 200 having one or more hydrogen purifiers 202 having a stack 130. The one or more hydrogen purifier stacks 130 may include any one or more of the hydrogen purifier cells disclosed herein, for example, one or more cells 10, one or more cells 50, and / or one or more cells 150, or a combination thereof. The one or more hydrogen purifier stacks 130 may be contained by end plates 204 and 206, as well as end plates 137 and 139 shown in Figure 4, for example.

[0105]

[0114] As shown in Figure 6, the hydrogen gas purification system 200 has one or more conduits or The system includes a hydrogen-containing gas source 208 operably connected to one or more hydrogen purifiers 202 via a pipe 210. The hydrogen-containing gas source 208 may be a storage tank, another gas purifier 202, one or more fuel cells, or one of various industrial processes. As disclosed herein, the hydrogen-containing gas source 208 typically contains at least some non-hydrogen or impurity gases such as nitrogen (N2), argon (Ar), carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), and / or oxygen (O2). As shown in Figure 6, the flow gas from the hydrogen-containing gas source 208 can be regulated by one or more flow control valves 212, e.g., manual or automatic valves controlled by a suitable control system (not shown), and / or a pressure regulator 213. In one embodiment, the hydrogen-containing gas 208 may be introduced into the system 200 under pressure by a gas pressurizing device (not shown), e.g., one or more blowers, fans, or compressors. In another embodiment, the hydrogen-containing gas 208 may be drawn into the system 200 by one or more gas decompression devices or vacuum devices (not shown), such as blowers, fans, or compressors. For example, a vacuum source may be operably connected to one or more conduits or pipes 214, one or more discharge conduits 220, and / or one or more discharge conduits 221 in Figure 6.

[0106]

[0115] As disclosed herein, the introduction of hydrogen-containing gas from source 208 and After appropriate oxidation and reduction, higher purity hydrogen gas is discharged from one or more hydrogen purifier stacks 202 into one or more conduits or pipes 214 and sent to storage or further processing 216. For example, further processing 216 may be a dryer or desiccator for removing at least some water vapor and / or for further purification, for example, for removing at least some trace impurities, if present. The purification process may include a pressure swing adsorption (PSA) system, a temperature swing adsorption (TSA), a "getter" gas purifier, or another gas purifier system 200. In one embodiment, further processing 216 may include a liquefaction device, such as a cryocooler. As shown in Figure 6, the flow of gas from one or more hydrogen purifier stacks 202 may be regulated by one or more flow control valves 218, for example, manual or automatic valves controlled by a suitable control system (not shown).

[0107]

[0116] As shown in Figure 6, typically, hydrogen-containing gas from source 208 Typically, the gas introduced into the storage unit 216 after passing through one or more hydrogen purification stacks 202 may have a pressure or a first pressure P1, and may typically have a higher pressure than the first pressure P1 or a third or output pressure P2, as disclosed herein. Pressure P2 may be any one of the output pressures disclosed herein. In one embodiment, pressure P2 may be lower than pressure P1, for example, when the hydrogen-containing gas 208 is drawn into the system 200, for example by vacuum.

[0108]

[0117] Furthermore, as shown in Figure 6, in one embodiment, one or more hydrogen purification stacks 20 2 may include one or more purifier cells 50 (and disclosed and described with respect to Figure 2) having an exhaust gas stream or replacement gas stream 58 and, possibly, a hydrogen-containing gas stream 59. As shown in Figure 6, the gas purifier system 200 includes one or more discharge conduits 220 for removing the gas stream 58 (Figure 2) and one or more discharge conduits 221 for removing anode exhaust gas (e.g., anode gas stream 13 shown in Figure 1) from one or more hydrogen purifier stacks 202, and the exhaust gas stream in the conduits 220 and / or exhaust gas stream in the conduits 221 can be directed to other processing, storage, or disposal 222. Other processing of the gas streams in the conduits 220 and 221 may include, for example, purification via another system 200, aeration to the atmosphere, combustion via a "flare," or other processing. As shown in Figure 6, the flow of gas discharged from one or more hydrogen purifier stacks 202 through the conduit 220 can be regulated by one or more flow control valves 224, for example, manual or automatic valves controlled by an appropriate control system (not shown). In one embodiment, at least a portion of the exhaust gas flow (flow 58 in Figure 2) may be introduced into a purifier 200, such as the purifier 200 shown in Figure 6 or another purifier 200, to recover and / or purify any hydrogen gas in the exhaust gas in the conduit 220. For example, as shown in Figure 6, at least a portion of the exhaust gas in the conduit 220 (flow 58 in Figure 2) can be sent to an input conduit 210 via a conduit or pipe 223 (shown by dashed lines in Figure 6). The flow in the conduit 223 may include appropriate flow control and / or pressure control (not shown), as disclosed herein.

[0109]

[0118] In one embodiment, one or more purifier cells 50 receive, for example, from a supply source 226. A hydrogen-containing "replenishment" gas flow 59 (see, for example, Figure 2) may be provided from a discharge conduit 214 from either or another system 200 or another hydrogen gas supply source via one or more conduits or pipes 228. The flow of "replenishment" gas through one or more conduits 228 to one or more hydrogen purifier stacks 202 may be regulated by one or more flow control valves 230, for example, manual or automatic valves controlled by a suitable control system (not shown). In one embodiment, the flow of "replenishment" gas to the cells of one or more hydrogen purifier stacks 202 may be regulated to control or "adjust" the purity of the hydrogen gas produced and transferred, for example, to storage or further processing 216. For example, the flow of “supplement” gas can be controlled to control the purity of the hydrogen gas produced, among other methods, by controlling one or more flow control valves 230, by adjusting the pressure in one or more stacks 202 (e.g., as detected by a pressure sensor 236), by introducing a flow control orifice (e.g., into a conduit 228), and / or by adjusting the “backdiffusion” of hydrogen gas through the membrane in the cells of the stack 202. In one embodiment, the flow of supplement gas (flow 59 in Figure 2) does not have to be supplied from an external source as shown in Figure 6, but may be supplied and delivered from within the stack 130, for example, from one or more cells 50 (see Figure 2) to one or more cells 50, and its flow may be adjusted and controlled based on flow and / or pressure.

[0110]

[0119] According to one aspect of the present invention, one or more gas purification systems 200 The temperature of the hydrogen purifier stack 130 is, in particular, important for the DMEA purification performance of stack 130. The temperature of the stack 130 can be adjusted and controlled to optimize and / or to avoid overheating of the stack 130. For example, in one embodiment, the temperature of the stack 130 can be maintained at least 30°C, but typically in the range of 50°C to 80°C. It is understood that reducing the operating temperature of the electrolyte in the cells of the stack 130 to, for example, 45°C to 55°C can improve the purity of the hydrogen gas produced while requiring more reasonable power consumption. In one embodiment, as shown in Figure 6, the temperature of one or more hydrogen purifier stacks 130 may be monitored and adjusted by one or more temperature sensors 232. The temperature of one or more hydrogen purifier stacks 130 detected by the temperature sensors 232 can be controlled by one or more heating or cooling circuits adjusted and controlled by a suitable control system (not shown). The heating or cooling circuits of one or more hydrogen purifier stacks 130 may include passages within the one or more hydrogen purifier stacks 130 through which a heating or cooling fluid can be passed to adjust the temperature of one or more hydrogen purifier stacks 130.

[0111]

[0120] According to one aspect of the present invention, the pressure of one or more hydrogen purifier stacks 130, The pressure of the gas from the supply source 208 and / or the pressure of the exhaust gas from the gas purification system 200 can, in particular, be adjusted and controlled to optimize the performance of the reaction in the DMEA of the stack 130. For example, in one embodiment, the pressure of the hydrogen gas produced by one or more stacks 130 can be monitored and adjusted by one or more pressure sensors 234. In some embodiments, it is understood that the pressure of the hydrogen gas produced in the system 200 may affect the purity of the hydrogen gas produced. The pressure of the produced hydrogen gas detected by the pressure sensors 234 can be adjusted and controlled by an appropriate control system (not shown).

[0112]

[0121] In addition, in one embodiment, the pressure of one or more stacks 130 is The performance of the DMEA, for example, efficiency, can be adjusted and controlled. In one embodiment, the pressure of the first cathode and / or second anode of one or more hydrogen purifier stacks 130 can be adjusted and controlled to improve the performance of the DMEA of the stacks 130, for example, efficiency. In one embodiment, as shown in Figure 6, the pressure of one or more stacks 130, for example, the pressure of the first cathode and / or second anode, may be monitored and adjusted by one or more pressure sensors 236. The pressure of one or more hydrogen purifier stacks 130 detected by the pressure sensors 236 can be controlled by a suitable control system (not shown).

[0113]

[0122] Figure 7 is a schematic diagram of a water electrolytic cell 250 according to another embodiment of the present invention. In some embodiments, the water electrolytic cell 250 comprises an electrochemical cell for electrolyzing water to generate hydrogen gas, specifically hydrogen gas with low levels of undesirable impurities such as oxygen (O2). As shown in Figure 7, the water electrolytic cell 250 is arranged and adapted to receive a water-containing feed or a first fluid flow 252. The first fluid flow 252 may contain liquid water and / or gaseous water (i.e., steam). (It should be understood that any reference to “fluid” in this specification may refer to a liquid fluid, a gaseous fluid, or both a liquid fluid and a gaseous fluid.) In some embodiments of the present invention, the cell 250 is adapted to produce a hydrogen gas flow or a third gas flow 254 that contains little or no oxygen gas and little or no gaseous impurities. The third gas flow 254 may be referred to as the exhaust gas flow 254.

[0114]

[0123] As schematically shown in Figure 7, the water electrolytic cell 250 is disclosed herein. Similar to hydrogen gas purifier cells, the water electrolytic cell 250 may have a multilayer structure, typically comprising components such as anodes and cathodes having thin planar or thin layered structures, and the structure shown in Figure 7, although not drawn to scale, may be a side view or axial cross section of the water electrolytic cell 250, drawn to facilitate the disclosure of the present invention.

[0115]

[0124] According to an aspect of the present invention, to provide the desired hydrogen gas 254, a water electrolytic cell Cell 250 typically includes a first MEA 256 and at least one second MEA 258. The first MEA 256 includes a first anode 260, which, in a manner similar to other anodes disclosed herein, is typically fluid-permeable, specifically water or gas-permeable, and at least a portion of the water in the first fluid flow 252 may pass through the anode 260, for example, in the axial direction as indicated by the arrows in the first fluid flow 252. In addition, the anode 260 may be permeable to gaseous oxygen (O2), hydrogen ions (H2), for example, according to Equation 3. + ), and electrons (e - The catalyst includes at least some catalysts, such as at least some platinum group metal-containing or iridium-containing catalysts, which are capable of enhancing the oxidation of water to ). H2O => 1 / 2O2 + 2e - +2H + formula 3

[0116]

[0125] In one embodiment, the distribution of the first fluid flow 252 around the surface of the anode 260 is strengthened. To achieve this, a conductive gas diffusion layer (GDL) and / or flow field insert, not shown in Figure 7, may be placed between the first fluid flow 252 and the anode 260. For example, the GDL may be applied to the surface of the anode 260 that is in contact with the first fluid flow 252. In one embodiment, the GDL used in the cell 250, or the GDL layer used in any embodiment disclosed herein, may be a metallic GDL, such as a platinum-coated titanium GDL, or an equivalent thereof.

[0117]

[0126] Due to the permeability of anode 260, water (H2O) enters anode 260. Due to the conductivity of anode 260, electrons (e -The hydrogen ions (H+) are conducted away from the anode 260, and according to an aspect of the present invention, the hydrogen ions (H+) generated at the anode 260 are introduced into the electrolyte 262. The electrolyte 262 may be any other electrolyte disclosed herein, for example, the electrolyte 262 may be an acidic electrolyte.

[0118]

[0127] As is typical in this art, at least the input or the first fluid flow 252 Some of the fluid may not diffuse through the anode 260 but may be removed as a fluid flow 264, for example, an "exhaust gas flow". Typically, the exhaust gas flow 264 may be captured and directed for further processing, or disposed of as needed, for example, through channels, manifolds, and ports.

[0119]

[0128] Electrolyte 262 or the first electrolyte 262 contains hydrogen ions (H + ) at least It is positioned and adapted to receive and move a portion of the ions. Because the anode 260 is in close proximity to the electrolyte 262, hydrogen ions (H + The hydrogen ions (H) move from the anode 260 to the electrolyte 262. The first electrolyte 262 includes a barrier between the first anode 260 and the electrode 266. The first electrolyte 262 contains hydrogen ions (H + The electrolyte can be any material or substance capable of selectively transferring hydrogen ions (H+), i.e., protons, from the first anode 260 to the electrode 266. That is, in one embodiment, the electrolyte 262, and any electrolyte disclosed herein, can be referred to as a “proton-conducting material” while substantially preventing gas flow. The first electrolyte 262 is typically an acidic polymer containing an acid, for example, perfluorosulfonic acid (PFSA). In one embodiment, the electrolyte 262 is a membrane or equivalent commercially available from The Chemours Company in Wilmington, Delaware under the trademark Nafion®. In other embodiments, the electrolyte 262 is any other acid, i.e., phosphoric acid [H3PO4], sulfuric acid [H2SO4], or any other hydrogen ions (H+ ) may contain one or more conductive acids. In one embodiment, the first electrolyte 262 may include a proton exchange membrane (PEM), as is known in the art.

[0120]

[0129] As is known in the art, "cathode" 266 or first cathode 2 Electrode 266, sometimes referred to as 66, receives hydrogen transferred by the first electrolyte 262. On (H + It is arranged to receive at least a portion of the electrons (e) according to formula 4, as is known in the art. - By reacting with the first electrolyte 262, hydrogen ions (H) pass through the electrolyte 262. + The catalyst contains, for example, a platinum group metal-containing catalyst, which is adapted to enhance at least some of the reactions (i.e., reductions) of the ) 2H + +2e - =>H2 formula 4

[0121]

[0130] As a result, or "generated," hydrogen gas (H2) 268, or hydrogen gas The second fluid flow 268 containing s(H2) is transported through the gas-permeable first cathode 266, as shown in Figure 7 as the gas flow 268 or second fluid flow 268.

[0122]

[0131] In one embodiment, the distribution of hydrogen gas (H2) around the surface of the second anode 270 To enhance this, a gas diffusion layer (GDL) and / or flow field insert, not shown in Figure 7, may be placed between the first cathode 266 and the second anode 270. For example, the GDL and / or flow field insert may be applied to the surface of the second anode 270.

[0123]

[0132] As shown in Figure 7, according to an embodiment of the present invention, a hydrogen gas (H2) is contained in the The fluid flow 268 can then be introduced into the second MEA 258, specifically into the electrode 270 or the second anode 270 of the second MEA 258. In the schematic diagram of the electrolytic cell 250 shown in Figure 7, the first MEA 256 is shown spaced apart from the second MEA 258 to facilitate the illustration and disclosure of the present invention. However, according to aspects of the present invention, the distance between the first MEA 256 and the second MEA 270 can be as small as, for example, the surface of the first cathode 266 can abut or contact the surface of the second anode 270. However, in one aspect, there may be at least some space, for example 0.1 millimeters [mm] to 0.5 mm, between the surface of the first cathode 266 and the surface of the second anode 270.

[0124]

[0133] According to an aspect of the present invention, in contrast to existing technologies, it has hydrogen gas (H2) The second fluid flow 268 can then be introduced into the second MEA 258 without removing or extracting the second fluid flow 268 from the electrolytic cell 250. In other words, while some portion of the second fluid flow 268 may undesirably "escape" from the electrolytic cell 250, according to one aspect of the present invention, substantially all of the second fluid flow 268 generated at the first cathode 266 is received by the second anode 270. For example, in one aspect, the second fluid flow 268 can be allowed to pass from the first cathode 266 of the MEA 258 to the second anode 270 of the MEA 258 without any intervening handling or processing, for example, without passing outside the electrolytic cell 250. In one aspect, the generated hydrogen gas (H2) formed at the first cathode 266 is substantially immediately converted into hydrogen ions (H2) at the second anode 270. + ) can be oxidized to ). In one embodiment, the second fluid flow 268 may be allowed to pass directly from the first cathode 266 of the MEA 258 in the electrolytic cell 250 to the second anode 270 of the MEA 258 without passing outside the electrolytic cell 250 before reaching the second cathode 270.

[0125]

[0134] The second anode 270 is connected to the second fluid flow 268 containing hydrogen gas (H2). Therefore, they are positioned to be in contact. The second anode 270 of the second MEA258 may be similar to, if not identical to, the first anode 260 of the MEA256. The second anode 270 may be permeable to hydrogen gas, and at least a portion of the hydrogen gas in the second fluid flow 268 may pass through the second anode 40 axially, for example, as indicated by the arrows in the second fluid flow 268. In addition, the second anode 270 is permeable to hydrogen ions (H) of the hydrogen gas, as shown by Equation 1 reproduced below. + Enhances oxidation to ) This includes at least some catalysts, for example, at least some platinum-containing catalysts. H2 => 2H + +2e - formula 1

[0126]

[0135] In one embodiment, the fraction of the second fluid flow 268 around the surface of the second anode 270 To enhance the distribution, a gas diffusion layer or GDL and / or flow field insert, not shown in Figure 7, may be placed between the second fluid flow 268 and the second anode 270. For example, the GDL and / or flow field insert may be applied to the surface of the second anode 270 that is in contact with the second fluid flow 268.

[0127]

[0136] According to an aspect of the present invention, the catalyst contained in the second anode 270 is the second flow The oxidation of hydrogen gas in body flow 268 is promoted or enhanced, and hydrogen ions (H) are produced according to formula 1 above. + ) and electrons (e - ) produces or generates. In one embodiment, electrons (e) generated at the second anode 270 - The first cathode 266 is directed back to the first cathode 266, as indicated by arrow 272 in Figure 7, and according to Equation 4, hydrogen ions (H) are released at the first cathode 266. + ) is used to reduce to hydrogen (H2) by electrons (e -At least a portion of ) can be supplied. Due to the permeability of the second anode 270, at least a portion of the hydrogen gas (H2) generated in the second anode 270 can pass through the second anode 270 and, according to an embodiment of the present invention, is introduced into or comes into contact with the electrolyte 274.

[0128]

[0137] The electrolyte 274 of MEA258 or the second electrolyte 274 is the second anode 2 Hydrogen ions (H) received from 70 + The second electrolyte 274 is arranged and adapted to receive and move at least a portion of the hydrogen ions (H). The second electrolyte 274 includes a gas barrier between the second anode 270 and the cathode 276. The second electrolyte 274 may be similar to the first electrolyte 262, if not substantially identical, and may contain hydrogen ions (H). + ) can transmit, for example, hydrogen ions (H + ), that is, it may include any material or substance that can selectively transfer protons from the second anode 270 to the cathode 276. In this case as described with respect to the first electrolyte 262, in one embodiment the second electrolyte 274 may be referred to as a “proton-conducting material”. The second electrolyte 274 is typically an acid, for example, containing one or more of the acids specified herein. However, in one embodiment the second electrolyte 274 may include PEM as is known in the art.

[0129]

[0138] The electrode 276 or second cathode 276 moves due to the second electrolyte 274. Hydrogen ions (H + The second cathode 276 is typically transparent and, according to Equation 2 reproduced below, receives at least some of the electrons (e). - ) using at least some hydrogen ions (H + The catalyst, for example, a platinum-containing catalyst, is adapted to enhance the reduction of ). 2H + +2e -=>H2 formula 2 The resulting or "generated" hydrogen gas (H2), or a third fluid flow 254 containing hydrogen gas (H2), is produced by the electrolytic cell 250.

[0130]

[0139] In one embodiment, hydrogen ions (H) around the surface of the second cathode 276 + ) portion To enhance the distribution, a gas diffusion layer (GDL) or flow field insert, not shown in Figure 7, may be placed between the second electrolyte 274 and the second cathode 276. For example, the GDL and / or flow field insert may be applied to the surface of the second cathode 276. In one embodiment, to enhance the removal of the third fluid flow 254, a GDL or flow field insert, not shown in Figure 7, may be placed adjacent to the downstream surface of the second cathode 276.

[0131]

[0140] According to an aspect of the present invention, the third fluid flow 254 of the electrolytic cell 250 is typically It may contain little to no undesirable impurity gases, for example, hydrogen gas (H2) that contains little to no oxygen gas.

[0132]

[0141] According to an aspect of the present invention, in the electrolytic cell 250, the second fluid flow 268 is M By passing the fluid from the first anode 266 of EA256 to the second cathode 270 of the second MEA258, a more efficient device can be provided that delivers purer hydrogen gas than conventional technology. In particular, the passage of the second fluid flow 268 from the first cathode 266 to the second anode 270 minimizes the content of impurities in the third fluid flow 254, such as oxygen gas impurities, for example.

[0133]

[0142] Figure 8 is a schematic diagram of a water electrolytic cell 300 according to another embodiment of the present invention. In some embodiments, the electrolytic cell 300 may have many of the features of the electrolytic cell 250, but further include at least one gas discharge or release between the MEAs. This reduction in the second fluid flow content is thought to reduce the partial pressure of non-hydrogen gases between the MEAs, for example, the partial pressure of oxygen, and thus reduce the driving force of the partial pressure gradient of undesirable non-hydrogen gases passing through the second MEA. In further embodiments, since some of the desired hydrogen gas is lost when a portion of the second fluid flow is removed, at least some hydrogen gas can be introduced between the MEAs to function as "replenishment" hydrogen gas for the hydrogen gas that may be lost with the removal of a portion of the second fluid flow.

[0134]

[0143] As shown in Figure 8, the water electrolytic cell 300 is supplied to the electrolytic cell 300 or The cell 300 is positioned and adapted to receive a first fluid flow 302. According to aspects of the present invention, the cell 300 is adapted to produce a hydrogen gas flow or a third fluid flow 304 that contains little or no oxygen gas and little gas impurities. The third gas flow 254 may be referred to as the exhaust gas flow 254. Similar to the electrolytic cell 250 as shown in Figure 8, the electrolytic cell 300 typically has a multilayer structure having components such as anodes and cathodes having thin planar or thin layered structures, and the structure shown in Figure 8 may be a side front view or an axial cross section view of the electrolytic cell 300, although it is not drawn to scale but is drawn to facilitate the disclosure of the present invention.

[0135]

[0144] In one embodiment, the electrolytic cell 300 shown in Figure 8 is substantially the same as the electrolytic cell 250. It is possible to have essentially the same first MEA306, that is, having a first anode 308, a first electrolyte 310, and a first cathode 312 to oxidize and reduce a first fluid flow 302 to produce a second fluid flow 314 containing hydrogen gas (H2), in substantially the same manner as the MEA256 of the electrolytic cell 250 shown in Figure 7. As is typical in the art, the input or at least a portion of the first fluid flow 302 may not be oxidized at the first anode 308 but may be removed as a fluid flow 303, for example, an "exhaust fluid flow". In addition, the electrolytic cell 300 may have a substantially identical second MEA 316 having a second anode 318, a second electrolyte 320, and a second cathode 322 in substantially the same manner as the electrolytic cell 250 shown in Figure 7, in order to oxidize and reduce the second fluid flow 314 and produce a third fluid flow 304 containing hydrogen gas (H2). However, according to the embodiment of the present invention shown in Figure 8, the electrolytic cell 300 includes at least one exhaust gas flow or replacement gas flow 324 having hydrogen gas and a non-hydrogen gas such as oxygen.

[0136]

[0145] In one embodiment, in order to enhance the distribution of gas flow around the electrode surface, as shown in Figure 8 One or more gas diffusion layers (GDLs) and / or gas distribution media that are not present can be placed within the electrolytic cell 300. For example, the electrolytic cell 300 may be associated with a first anode 308, a first cathode 312, a second anode 318, and / or a second cathode 322. This may include a GDL and / or flow field insert.

[0137]

[0146] According to this embodiment, the first fluid flow 302 is processed and the first MEA 306 After passing through and generating a second fluid flow 314 having a hydrogen gas content and a non-hydrogen gas content 36, at least a portion of the second fluid flow 314 is removed via fluid flow 324. The removal of fluid flow 324 from fluid flow 314 results in a modified or intermediate fluid flow 326. According to an aspect of the present invention, the removal of fluid flow 324 reduces the partial pressure of non-hydrogen gas in the modified fluid flow 326, and this reduction in partial pressure reduces the partial pressure gradient across the second MEA 316 of the non-hydrogen gas content, which reduces the passage of non-hydrogen gas to the third fluid flow 304 through the second MEA 316. Thus, according to an aspect of the present invention, the non-hydrogen gas content of the third fluid flow 304, for example, the oxygen gas content, is reduced, providing a purer hydrogen gas flow.

[0138]

[0147] The removal of the fluid flow 324 can be carried out by various means. One embodiment Alternatively, the fluid flow 324 may be removed by simply exhausting at least a portion of the second fluid flow 314, for example, through the inherent gap between the first MEA 306 and the second MEA 316, for example, through the inherent space or gap between the surface of the first cathode 312 and the second anode 318. In another embodiment, the fluid flow 324 may be removed by providing a path, channel, or groove, for example, a radial or transverse channel or groove, in the mating surface of the first cathode 312, the mating surface of the second anode 318, or both the mating surfaces of the first cathode 312 and the second anode 318. In yet another embodiment, the fluid flow 324 may be removed through a GDL and / or flow field insert positioned between the mating surface of the first cathode 312 and the mating surface of the second anode 318. As is known in the art, the GDL is typically a porous material such as carbon paper through which the gas flow 324 can pass. In another embodiment, the fluid flow 324 can be removed by providing a path for the fluid flow 324 by providing one or more spacers between the mating surface of the first cathode 312 and the mating surface of the second anode 318. In one embodiment, a near-atmospheric pressure source, i.e., a vacuum, can be introduced to draw out at least a portion of the second fluid flow 314 through the fluid flow 324.

[0139]

[0148] According to another aspect of the present invention, the first fluid flow 302 is processed and the first MEA After passing through 306 to generate a second fluid flow 314, at least some hydrogen gas can be introduced into the second fluid flow 314. As shown in Figure 8, in one embodiment, hydrogen gas can be introduced into the second fluid flow 314 via fluid flow 324 (shown by dashed lines in Figure 8) to replace the hydrogen gas lost from the second fluid flow 314 via fluid flow 328, thereby generating a reformed fluid flow 326. In one embodiment, fluid flow 328 may be, for example, high-purity hydrogen gas having at least a higher purity than the hydrogen content of the first fluid flow 302, but in other embodiments, fluid flow 328 may be a hydrogen gas-containing flow having at least some hydrogen gas content, or it may have a non-hydrogen gas content.

[0140]

[0149] Introduction of a hydrogen-containing gas flow 328 to the electrolytic cell 300, for example, a "supplement gas flow". This may be carried out with or without the removal of the fluid flow 324. The introduction of the fluid flow 328 into the second fluid flow 314 can be carried out in any one or more convenient ways by introducing the hydrogen gas-containing flow 328, for example, through a gas-permeable electrolyte 310 driven by a hydrogen gas partial pressure gradient, or through a gas-permeable first cathode 312, through a gas-permeable GDL and / or flow field insert, or through a channel in the first cathode 312, a channel in the second anode 318, or through channels in both the first cathode 312 and the second anode 318. Any channels that can be provided for the hydrogen gas-containing flow 328 may be located on one or both of the opposing surfaces of the first cathode 312 and the second anode 318.

[0141]

[0150] In one embodiment, the supplement hydrogen gas flow 328 is a third fluid flow 3 having a hydrogen content. This may include at least a portion of 04. For example, at least a portion of the third fluid flow 304 may be introduced into the second fluid flow 314 by diffusion through the second electrolyte 320, as shown by the dashed line by the gas flow 328A in Figure 8. This diffusion through the second electrolyte 320 may be referred to as “reverse diffusion” of at least a portion of the third fluid flow 304 having at least a portion of hydrogen gas (H2). The supplement gas flow 328 may be provided by any one or more of these sources or mechanisms.

[0142]

[0151] In another aspect of the present invention, the three-electrode cell 150 shown in Figure 5 also functions as an electrolytic cell. This is possible. For example, as shown in Figure 5, the DMEA 152 of the purifier cell 150 includes a first anode 166, a first electrolyte 168, a first cathode / second anode (or “dual electrode”) 170, a second electrolyte 172, and a second cathode 174. Similar to the components and operation of the electrolytic cell 250 shown in Figure 7, in the electrolytic cell 150 shown in Figure 5, the anode 166 may have all the features of the first anode disclosed herein, the first electrolyte 168 and the second electrolyte 172 may have all the features of the electrolyte disclosed herein, and the second cathode 174 may have all the features of the second cathode disclosed herein. In this aspect of the present invention, the components and fluid flow of the electrolytic cell 150 shown in Figure 5 may have all the functions and features of the purifier cell 150 disclosed herein, including oxidation at the first anode 166 according to Formula 3 and reduction at the second cathode 174 according to Formula 4. However, in the case of the electrolytic cell 150, the first fluid flow 154 in Figure 5 may contain liquid water and / or gaseous water (i.e., vapor). (It should be understood that any reference to “fluid” in this specification may refer to a liquid fluid, a gaseous fluid, or both a liquid fluid and a gaseous fluid.) According to aspects of the present invention, the electrolytic cell 150 in Figure 5 may be adapted to produce a hydrogen gas flow or a third fluid flow 160 that contains little or no oxygen gas and little or no gaseous impurities.

[0143]

[0152] According to an aspect of the present invention, one or more water electrolysis cells 250 and 300 are provided, High-purity hydrogen gas can be generated. In one embodiment, a water electrolysis stack having one or more electrolytic cells 250 and / or 300, for example, a water electrolysis stack similar to the hydrogen purifier stack 130 shown in Figure 4, may be provided. In another embodiment, a water electrolysis cell system having one or more electrolytic cell stacks having one or more electrolytic cells 250 and / or 300, for example, a water electrolysis similar to the hydrogen purifier system 200 shown in Figure 6, may be provided.

[0144]

[0153] As disclosed above, embodiments of the present invention, in many of their forms, The present invention provides improved hydrogen purification and water electrolysis that can meet and exceed the hydrogen gas purity requirements of hydrogen gas users. Embodiments of the present invention utilize a unique combination of membrane electrode assemblies (MEAs) or double MEAs (DMEAs) that have been shown to provide the required high hydrogen gas purity.

[0145]

[0154] The terms used herein are for the sole purpose of describing specific embodiments. and is not intended to limit this disclosure. Where used herein, the singular forms "a," "an," and "the" are intended to include the plural form unless the context explicitly indicates otherwise. "comprises" and / or "comprising" It will be further understood that, when used herein, the term ) specifies the existence of the described feature, integer, step, action, element, and / or component, but does not exclude the existence or addition of one or more other features, integers, steps, actions, elements, components, and / or groups thereof.

[0146]

[0155] All meanings or step plus funks in the following claims The corresponding structures, materials, actions, and equivalents of the Combination elements are intended to include any structures, materials, or actions for performing a function in combination with other claimed elements specifically claimed. The descriptions in this disclosure are presented for illustrative and explanatory purposes, but are not intended to be exhaustive or to limit the disclosure to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of this disclosure. The embodiments have been selected and described to best illustrate the principles and practical applications of this disclosure and to enable others skilled in the art to understand this disclosure in terms of various embodiments with various modifications suitable for the particular use intended.

[0147]

[0156] Although several aspects of the present invention have been described and illustrated herein, the same objective is Those skilled in the art can implement alternative embodiments to achieve this. Therefore, the appended claims are intended to encompass all such alternative embodiments that fall within the true spirit and scope of the invention.

Claims

1. A hydrogen gas purification cell (10, 50, 150), A first membrane electrode assembly (MEA) (24), A first anode (28) is positioned in contact with a first gas stream (12) having a first hydrogen gas content and a first impurity gas content, and contains a catalyst adapted to oxidize at least a portion of the first hydrogen gas content to generate hydrogen ions and electrons, A first electrolyte (30) is positioned and adapted to receive and transfer at least a portion of the hydrogen ions generated by the first anode (28), A first MEA (24) comprising: a first cathode (32) disposed to receive at least a portion of the hydrogen ions moved by the first electrolyte (30), and containing a catalyst adapted to reduce the at least portion of the hydrogen ions to produce a second gas stream (38) having a second hydrogen gas content greater than the first hydrogen gas content and a second impurity gas content less than the first impurity gas content; The second MEA (26), A second anode (40) is configured to receive the second gas stream (38) from the first cathode (32) of the first MEA, and contains a catalyst adapted to oxidize at least a portion of the second hydrogen gas content in the second gas stream (38) to generate hydrogen ions and electrons, A second electrolyte (42) is positioned and adapted to receive and transfer at least a portion of the hydrogen ions generated by the second anode (40), A second MEA (26) comprising: a second cathode (44) disposed to receive at least a portion of the hydrogen ions moved by the second electrolyte (42) of the second MEA, and containing a catalyst adapted to reduce the at least portion of the hydrogen ions to produce a third gas stream (18, 52) having a third hydrogen gas content greater than the first hydrogen gas content and a third impurity gas content less than the first impurity gas content; A hydrogen gas purification cell (10, 50, 150) is provided.

2. The hydrogen gas purifier cell (10, 50, 150) according to claim 1, further comprising at least one passage between the first electrolyte (30) and the second electrolyte (42) for discharging at least a portion of the second gas flow (38).

3. The hydrogen gas purifier cell (10, 50, 150) according to claim 2, wherein the at least one passage is located between the first cathode (32) and the second anode (40).

4. The hydrogen gas purifier cell (10, 50, 150) according to claim 3, wherein the at least one passage located between the first cathode and the second anode includes a gap (101) between the mating surfaces of the first cathode and the second anode.

5. The hydrogen gas purifier cell (10, 50, 150) according to claim 3, further comprising a gas permeable layer (GDL) (105) between the first cathode and the second anode, wherein the GDL provides the at least one passage located between the first cathode and the second anode.

6. The hydrogen gas purifier cell (10, 50, 150) according to claim 5, wherein the GDL (105) includes a carbon-based gas permeable layer.

7. The hydrogen gas purifier cell (10, 50, 150) according to any one of claims 2 to 6, wherein the at least one passage comprises at least one channel adjacent to at least one of the first cathode and the second anode.

8. The hydrogen gas purifier cell (10, 50, 150) according to any one of claims 1 to 7, further comprising at least one passage between the first electrolyte and the second electrolyte for introducing a hydrogen-containing gas into the second gas stream.

9. The hydrogen gas purifier cell (10, 50, 150) according to claim 8, wherein the at least one passage is located between the first cathode and the second anode.

10. The hydrogen gas purifier cell (10, 50, 150) according to claim 9, wherein the at least one passage located between the first cathode and the second anode includes a gap between the mating surfaces of the first cathode and the second anode.

11. The hydrogen gas purifier cell (10, 50, 150) according to claim 9, further comprising a gas permeable layer (GDL) (105) between the first cathode and the second anode, wherein the GDL provides the at least one passage located between the first cathode and the second anode.

12. The hydrogen gas purifier cell (10, 50, 150) according to any one of claims 8 to 11, wherein the at least one passage comprises at least one channel on the surface of at least one of the first cathode and the second anode.

13. A hydrogen gas purifier cell (10, 50, 150) according to any one of claims 1 to 12, wherein the first gas flow includes a first gas pressure, and the third gas flow includes a third gas pressure, the third gas pressure being greater than the first gas pressure.

14. A hydrogen gas purifier cell (10, 50, 150) according to any one of claims 1 to 13, wherein the catalyst in the first anode, the first cathode, the second anode, and the second cathode comprises a platinum group metal-containing catalyst.

15. The hydrogen gas purifier cell (10, 50, 150) according to any one of claims 1 to 14, wherein the first electrolyte and the second electrolyte include at least an acidic electrolyte.

16. A method for reducing the impurity gas content of a gas stream (12) having a hydrogen gas content (14) and an impurity gas content (16), Introducing a first gas stream (12) having a first hydrogen content and a first impurity gas content into a first anode (28) containing a catalyst, In the first anode (28), at least a portion of the first hydrogen gas content is catalytically oxidized to generate hydrogen ions and electrons, To move at least a portion of the hydrogen ions and diffuse at least a portion of the impurity gas content through the first electrolyte (30) to the first cathode (32) containing the catalyst, In the first cathode (32), at least a portion of the hydrogen ions that have moved through the first electrolyte (30) are catalytically reduced to generate a second gas stream (38) having a second hydrogen content (34) greater than the first hydrogen content and a second impurity gas content (36) less than the first impurity gas content. The second gas flow (38) is introduced into the second anode (40) having a catalyst, In the second anode (40), at least a portion of the second hydrogen gas content in the second gas stream (38) is catalytically oxidized to generate hydrogen ions and electrons, To move at least a portion of the hydrogen ions generated at the second anode (40) and to diffuse at least a portion of the second impurity gas content (36) to the second cathode (44) through the second electrolyte (42), In the second cathode (44), at least a portion of the hydrogen ions that have moved through the second electrolyte (42) are catalytically reduced to generate a third gas stream (18, 52) having a third hydrogen content (54) greater than the first hydrogen content and a third impurity gas content (56) less than the first impurity gas content. Methods that include...

17. The method according to claim 16, further comprising removing at least a portion of the second gas flow (38) to generate a reformed gas flow (66) having a non-hydrogen gas partial pressure lower than the non-hydrogen gas partial pressure in the second gas flow.

18. The method according to claim 17, wherein introducing the second gas flow to the second anode includes introducing the reformed gas flow (66) to the second anode.

19. The method according to claim 17 or 18, wherein removing at least a portion of the second gas flow (38) includes removing at least a portion of the second gas flow through a passage between the first electrolyte and the second electrolyte.

20. The method according to claim 19, wherein the passage is located between the first cathode and the second anode.

21. The method according to claim 20, wherein the passage located between the first cathode and the second anode includes a gap (101) between the mating surfaces of the first cathode and the second anode.

22. The method according to claim 20 or 21, wherein removing at least a portion of the second gas flow (38) includes removing at least a portion of the second gas flow through a gas diffusion layer (GDL) (105) disposed between the first cathode and the second anode.

23. The method according to any one of claims 20 to 22, wherein removing the at least portion of the second gas flow includes removing the at least portion of the second gas flow through at least one channel in the surface of at least one of the first cathode and the second anode.

24. The method according to any one of claims 16 to 23, further comprising introducing a portion of hydrogen gas (59) into the second gas stream.

25. The method according to claim 24, wherein introducing a portion of hydrogen gas into the second gas flow replenishes at least a portion of the hydrogen gas (59A) removed from the second gas flow.

26. The method according to any one of claims 16 to 25, wherein the third hydrogen content is at least 99.999 volume percent of hydrogen on a dry basis.

27. The third impurity gas content is a maximum of 10 ppm on a dry basis, claims 16-2 The method described in any one of item 6.

28. A method for reducing the impurity gas content of a gas stream (12) having a hydrogen gas content (14) and an impurity gas content (16), A first gas stream (12) having a first hydrogen content (14) and a first impurity gas content (14) is introduced into a first membrane electrode assembly (MEA) (24) having a first anode (28) containing a catalyst, a first electrolyte (30), and a first cathode (32) to generate a second gas stream (38) having a second hydrogen gas content (34) and a second impurity gas content (36). The second gas stream (38) is passed directly through a second MEA (26) having a second anode (40) containing a catalyst, a second electrolyte (42), and a second cathode (44) to generate a third gas stream (18, 52) having a third hydrogen gas content (20, 54) greater than the first hydrogen content and a third impurity gas content (22, 56) less than the first impurity gas content. A method that includes this.

29. The method according to claim 28, wherein the first MEA (24) and the second MEA (26) are arranged within a hydrogen purification cell (10, 50, 150), and passing the second gas flow directly through the second MEA (26) is to pass the second gas flow through the second MEA without allowing the second gas flow to leave the hydrogen purification cell.

30. The method according to claim 28 or 29, further comprising removing at least a portion of the second gas flow (38) to produce a modified second gas flow (66) having a reduced non-hydrogen gas partial pressure than the second gas flow.

31. The method according to claim 30, further comprising introducing at least a portion of hydrogen gas (59, 59A) into the second gas stream.

32. A hydrogen gas purification system (200), The at least one hydrogen gas purification cell (10, 50, 150) according to claim 1, At least two conductive plates (204, 206), one of which is attached to a first end of the at least one hydrogen gas purifier cell (10), and the other of which is attached to a second end of the at least one hydrogen gas purifier cell on the opposite side of the first end, A hydrogen gas purification system (200) equipped with [the following].

33. The hydrogen gas purification system (200) according to claim 32, wherein the at least one hydrogen gas purification cell comprises a plurality of hydrogen gas purification cells (10, 50, 150).

34. The hydrogen gas purification system (200) according to claim 32 or 33, wherein the plurality of hydrogen gas purification cells include a stack of hydrogen gas purification cells.

35. The hydrogen gas purification system (200) according to any one of claims 32 to 34, further comprising a power supply adapted to provide voltage and current to the at least one hydrogen gas purification cell.

36. The hydrogen gas purification system (200) according to claim 35, wherein the power supply includes a DC power supply.

37. A hydrogen gas purification system (200), The at least one hydrogen gas purification cell (10, 50, 150) according to claim 2, At least two conductive plates (204, 206), one of which is attached to the first end of the at least one hydrogen gas purifier cell (10, 50, 150), and one of which is attached to the second end of the at least one hydrogen gas purifier cell on the opposite side of the first end, A hydrogen gas purification system (200) equipped with [the following].

38. The hydrogen gas purification system (200) according to claim 37, further comprising at least one manifold (143) operably connected to the at least one passage for discharging at least a portion of the second gas flow.

39. The hydrogen gas purification system (200) according to claim 38, wherein the at least one manifold (143) is operably connected to a conduit having a control valve adapted to regulate the flow of at least a portion of the discharge of the second gas flow.

40. The hydrogen gas purification system (200) according to claim 39, further comprising a conduit for directing at least a portion of the flow of the discharged second gas stream to the inlet of the at least one hydrogen gas purification cell.

41. A hydrogen gas purification cell (10, 50, 150), The device comprises a membrane electrode assembly (MEA) (152), and the MEA (152) is an anode (166) disposed in contact with a first gas stream (154) having a first hydrogen gas content (156) and a first impurity gas content (158), the anode (166) containing a catalyst adapted to oxidize at least a portion of the first hydrogen gas content to generate hydrogen ions and electrons, A first electrolyte (168) arranged and adapted to receive and transfer at least a portion of the hydrogen ions received from the anode, A double electrode (170) is arranged to receive at least a portion of the hydrogen ions moved by the first electrolyte, wherein the double cathode contains a catalyst adapted to reduce at least a portion of the hydrogen ions to generate a second gas stream having a second hydrogen gas content, and to oxidize at least a portion of the second hydrogen gas content in the second gas stream to generate hydrogen ions and electrons, A second electrolyte (172) is positioned and adapted to receive and transfer at least a portion of the hydrogen ions received from the double electrode, A cathode (174) arranged to receive at least a portion of the hydrogen ions transferred by the second electrolyte, comprising a catalyst adapted to reduce at least a portion of the hydrogen ions and electrons to produce a third gas stream (160) having a third hydrogen gas content (162) greater than the first hydrogen gas content and a third impurity gas content (164) less than the first impurity gas content, A hydrogen gas purification cell (10, 50, 150) is provided.

42. The hydrogen gas purifier cell (10, 50, 150) according to claim 41, further comprising at least one passage for removing at least a portion of the second gas flow.

43. The hydrogen gas purifier cell (10, 50, 150) according to claim 42, wherein the at least one passage includes the double electrode (170).

44. The hydrogen according to claim 43, wherein the at least one passage includes permeability of the double electrode. Gas purification cells (10, 50, 150).

45. The hydrogen gas purifier cell (10, 50, 150) according to any one of claims 42 to 44, wherein the at least one passage includes a gas-permeable diffusion layer.

46. The hydrogen gas purifier cell (10, 50, 150) according to any one of claims 42 to 45, wherein the at least one passage contains the second electrolyte.

47. The hydrogen gas purifier cell (10, 50, 150) according to any one of claims 41 to 46, further comprising at least one passage for introducing at least a portion of hydrogen gas into the second gas flow.

48. The hydrogen gas purifier cell (10, 50, 150) according to claim 47, wherein the at least one passage includes the double electrode.

49. The hydrogen gas purifier cell (10, 50, 150) according to any one of claims 42 to 48, wherein the at least one passage includes a gas-permeable diffusion layer.

50. The hydrogen gas purifier cell (10, 50, 150) according to any one of claims 42 to 49, wherein the at least one passage contains the second electrolyte.

51. A method for purifying hydrogen gas, A first gas stream (154) having a first hydrogen gas content (156) and a first impurity gas content (158) is introduced into an anode (160) containing a catalyst. In the anode (160), at least a portion of the first hydrogen gas content is catalytically oxidized to generate hydrogen ions and electrons, At least a portion of the hydrogen ions generated at the anode are transferred to the double electrode (170) through the first electrolyte (168), In the double electrode (170), at least a portion of the hydrogen ions that have moved through the first electrolyte is catalytically reduced to generate a second gas stream having a second hydrogen gas content, and at least a portion of the second hydrogen gas content in the second gas stream is catalytically oxidized to generate hydrogen ions and electrons. At least a portion of the hydrogen ions generated in the double electrode are transferred to the cathode (174) through the second electrolyte (172), In the cathode (174), at least a portion of the hydrogen ions that have moved through the second electrolyte are catalytically reduced to generate a third gas stream (160) having a third hydrogen gas content (162) greater than the first hydrogen gas content and a third impurity gas content (164) less than the first impurity gas content. Methods that include...

52. The method according to claim 51, further comprising removing at least a portion of the second gas flow.

53. The method according to claim 52, wherein the MEA further comprises a gas diffusion layer, and removing the at least portion of the second gas flow includes removing the at least portion of the second gas flow through the gas diffusion layer.

54. The method according to claim 51 or 52, wherein the double electrode (170) comprises a gas-permeable electrode, and removing at least a portion of the second gas flow includes removing at least a portion of the second gas flow through the gas-permeable double electrode.

55. The method according to any one of claims 52 to 54, wherein removing the at least portion of the second gas flow includes removing the at least portion of the second gas flow through the second electrolyte.

56. The method according to any one of claims 51 to 55, further comprising introducing at least a portion of hydrogen gas (180) into the second gas stream.

57. The method according to claim 56, wherein the MEA further comprises a gas diffusion layer, and introducing the at least portion of the hydrogen gas (180) into the second gas flow includes introducing the at least portion of the hydrogen gas into the second gas flow through the gas diffusion layer.

58. The method according to claim 56 or 57, wherein the double electrode (170) comprises a gas-permeable electrode, and the introduction of at least a portion of the hydrogen gas (180) into the second gas flow includes introducing the at least portion of the hydrogen gas into the second gas flow through the gas-permeable double electrode.

59. The method according to any one of claims 56 to 58, wherein introducing at least a portion of the hydrogen gas (180) into the second gas flow includes introducing at least a portion of the hydrogen gas into the second gas flow through the second electrolyte.

60. The method according to any one of claims 51 to 59, wherein the third impurity gas content (164) includes a maximum of 10 ppm of impurity gas on a dry basis.

61. A water electrolytic cell (250), A first membrane electrode assembly (MEA) (256), The first H ２ A first anode (260) arranged to be in contact with the O-containing fluid flow (252), wherein the first H ２ The H in the O-containing fluid flow ２ A first anode (260) containing a catalyst adapted to oxidize at least a portion of O to produce oxygen gas, hydrogen ions, and electrons, A first electrolyte (262) is positioned and adapted to receive and transfer at least a portion of the hydrogen ions generated by the first anode (260), A first MEA (256) comprising: a first cathode (266) arranged to receive at least a portion of the hydrogen ions moved by the first electrolyte (262), and containing a catalyst adapted to reduce the at least a portion of the hydrogen ions to produce a second fluid flow (268) containing hydrogen gas; The second MEA (258), A second anode (270) is configured to receive the second fluid flow (268) containing hydrogen gas from the first cathode of the first MEA, and contains a catalyst adapted to oxidize at least a portion of the hydrogen gas to produce hydrogen ions and electrons, A second electrolyte (274) is positioned and adapted to receive and transfer at least a portion of the hydrogen ions generated by the second anode, A second MEA (258) comprising: a second cathode (276) arranged to receive at least a portion of the hydrogen ions transferred by the second electrolyte of the second MEA, and containing a catalyst adapted to reduce the at least a portion of the hydrogen ions to produce a third fluid flow containing hydrogen gas; A water electrolytic cell (250) equipped with the above.

62. The water electrolytic cell (250) according to claim 61, further comprising at least one passage between the first electrolyte and the second electrolyte for discharging at least a portion of the second fluid flow.

63. The water electrolytic cell (250) according to claim 62, wherein the at least one passage is located between the first cathode and the second anode.

64. The water electrolytic cell purifier cell (250) according to claim 63, wherein the at least one passage located between the first cathode and the second anode includes a gap (101) between the mating surfaces of the first cathode and the second anode.

65. The water electrolytic cell (250) according to claim 63 or 64, further comprising a gas permeable layer (GDL) (105) between the first cathode and the second anode, wherein the GDL provides the at least one passage located between the first cathode and the second anode.

66. The water electrolytic cell (250) according to any one of claims 61 to 65, further comprising at least one passage between the first electrolyte and the second electrolyte for introducing a hydrogen-containing gas into the second gas flow.

67. The water electrolytic cell (250) according to claim 66, wherein the at least one passage is located between the first cathode and the second anode.

68. The water electrolytic cell (250) according to claim 67, wherein the at least one passage located between the first cathode and the second anode includes a gap between the mating surfaces of the first cathode and the second anode.

69. The water electrolytic cell (250) according to claim 67 or 68, further comprising a gas permeable layer (GDL) between the first cathode and the second anode, wherein the GDL provides the at least one passage located between the first cathode and the second anode.

70. The water electrolytic cell (250) according to any one of claims 61 to 69, wherein the at least one passage comprises at least one channel on the surface of at least one of the first cathode and the second anode.

71. A method for electrolyzing water, The first H ２ Introducing an O-containing fluid flow (252) into a first anode (260) containing a catalyst, In the first anode (260), the first H ２ The H in the O-containing fluid flow ２ Catalytically oxidizing at least a portion of O to produce oxygen gas, hydrogen ions, and electrons, Transferring at least a portion of the hydrogen ions to a first cathode (266) containing a catalyst through a first electrolyte (262), In the first cathode (266), at least a portion of the hydrogen ions that have moved through the first electrolyte are catalytically reduced to generate a second gas stream containing hydrogen gas, The second gas stream containing the hydrogen gas is introduced into the second anode (270) having a catalyst. In the second anode (270), at least a portion of the hydrogen gas in the second gas stream is catalytically oxidized to generate hydrogen ions and electrons, Transferring at least a portion of the hydrogen ions generated at the second anode to the second cathode (276) through the second electrolyte (274), In the second cathode (276), at least a portion of the hydrogen ions that have moved through the second electrolyte are catalytically reduced to generate a third gas stream (254) containing hydrogen gas, Methods that include...

72. The method according to claim 71, further comprising removing at least a portion of the second gas flow (268) to generate a reformed gas flow having a non-hydrogen gas partial pressure.

73. The method according to claim 72, wherein introducing the second gas flow (268) to the second anode (270) includes introducing the reformed gas flow to the second anode.

74. The method according to claim 73, wherein removing at least a portion of the second gas flow (268) includes removing at least a portion of the second gas flow through a passage between the first electrolyte and the second electrolyte.

75. The method according to claim 74, wherein the passage is located between the first cathode and the second anode.

76. The method according to claim 75, wherein the passage located between the first cathode and the second anode includes a gap between the mating surfaces of the first cathode and the second anode.

77. The method according to claim 75 or 76, wherein removing at least a portion of the second gas flow includes removing at least a portion of the second gas flow through a gas diffusion layer (GDL) positioned between the first cathode and the second anode.

78. The method according to any one of claims 75 to 77, wherein removing the at least portion of the second gas flow includes removing the at least portion of the second gas flow through at least one channel in the surface of at least one of the first cathode and the second anode.

79. The method according to any one of claims 71 to 78, further comprising introducing a portion of hydrogen gas into the second gas flow (268).

80. The method according to any one of claims 72 to 79, further comprising introducing a portion of hydrogen gas into the second gas flow (268) to replenish at least a portion of the hydrogen gas removed from the second gas flow.

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