Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B1/00—Electrolytic production of inorganic compounds or non-metals
  • C25B1/01—Products
  • C25B1/02—Hydrogen or oxygen
  • C25B1/04—Hydrogen or oxygen by electrolysis of water
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B15/00—Operating or servicing cells
  • C25B15/08—Supplying or removing reactants or electrolytes; Regeneration of electrolytes
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
  • C25B9/60—Constructional parts of cells
  • C25B9/65—Means for supplying current; Electrode connections; Electric inter-cell connections
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
  • C25B9/70—Assemblies comprising two or more cells
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
  • C25B9/70—Assemblies comprising two or more cells
  • C25B9/73—Assemblies comprising two or more cells of the filter-press type
  • C25B9/77—Assemblies comprising two or more cells of the filter-press type having diaphragms

Definitions

• the present invention relates to a structure of a water electrolytic hydrogen production system, and particularly relates to a technique effective for application to a large-scale water electrolytic hydrogen production system configured by connecting a plurality of water electrolysis stacks in series.
• a large-scale water electrolytic hydrogen production system has a plurality of water electrolysis stacks within the system.
• a power supply is required for electrolysis of water in the water electrolysis stacks.
• PTL 1 discloses "a high-pressure container storage type water electrolytic hydrogen generation device with a simple configuration and ease of assembly, and that is capable of generating a large amount of hydrogen".
• PTL 1 describes a configuration in which a power supply is connected to each of a plurality of water electrolysis stacks (a water electrolysis tank in PTL 1) independently, and a configuration in which a single power supply is connected to the water electrolysis stacks connected in series.
• the power supply configuration is more simplified by the configuration in which the water electrolysis stacks are connected in series and one power supply is connected.
• PTL 2 discloses "a water electrolysis system capable of achieving high efficiency of the entire system with a simple and compact configuration without wastefully discarding hydrogen dissolved in high-pressure water".
• PTL 2 describes an internal configuration of a water electrolysis stacks (in PTL 2, an electrolysis stack), and an electrolysis portion in which a water electrolysis reaction actually occurs in the water electrolysis stacks (in PTL 2, a portion constituted by terminal portions 38a and 38b and a laminated portion of portion cells 30) is electrically insulated from other portions by an insulation (insulating plates 34a, 34b), and the insulation is provided inside the water electrolysis stack.
• the electrolysis portion is electrically grounded from the viewpoint of durability and reliability of the entire apparatus.
• the electrolysis portion is insulated from the other portions.
• the portions other than the electrolysis portion are electrically grounded in general, the potential is electrically uniform.
• the larger the number of water electrolysis stacks the larger the maximum potential difference (maximum voltage) between the electrolysis portion insulated in the water electrolysis stacks and the portions other than the electrolysis portion.
• an insulation inside does not have sufficient insulation performance for ensuring insulation with respect to a voltage generated in a large number of water electrolysis stacks connected in series.
• an object of the present invention is to provide a water electrolytic hydrogen production system configured by connecting a plurality of water electrolysis stacks in series, wherein the system is capable of ensuring sufficient insulation performance of each of the water electrolysis stacks.
• the present invention provides a water electrolytic hydrogen production system including a plurality of water electrolysis apparatuses, wherein each of the water electrolysis apparatuses includes: a water electrolysis stack configured to generate hydrogen and oxygen by electrolysis of water; a water supply portion configured to supply water to the water electrolysis stack; a water intake portion configured to take water into the water supply portion from outside; a hydrogen release portion configured to release hydrogen generated in the water electrolysis stack to outside; and an oxygen release portion configured to release oxygen generated in the water electrolysis stack to outside, the water electrolysis stacks of the plurality of water electrolysis apparatuses are electrically connected to each other in series, and an insulation member is disposed at a connecting portion of piping for supplying or releasing a fluid with outside of the apparatus, the piping including at least the water intake portion, the hydrogen release portion, and the oxygen release portion of each of the plurality of water electrolysis apparatuses.
• the present invention provides a water electrolytic hydrogen production system including a plurality of water electrolysis apparatuses, wherein each of the water electrolysis apparatuses includes: a water electrolysis stack configured to generate hydrogen and oxygen by electrolysis of water; a water supply portion configured to supply water to the water electrolysis stack; a water intake portion configured to take water into the water supply portion from outside; a hydrogen release portion configured to release hydrogen generated in the water electrolysis stack to outside; and an oxygen release portion configured to release oxygen generated in the water electrolysis stack to outside, the water electrolysis stacks of the plurality of water electrolysis apparatuses are electrically connected to each other in series, and an insulation member is disposed in piping between at least one of the water intake portion, the hydrogen release portion, and the oxygen release portion, and the water electrolysis stack.
• a water electrolytic hydrogen production system configured by connecting a plurality of water electrolysis stacks in series, wherein the system is capable of ensuring sufficient insulation performance of each of the water electrolysis stacks.
• FIG. 12 is a diagram showing a schematic configuration of a conventional multi-series water electrolytic hydrogen production system.
• FIG. 12 shows an example in which ten water electrolysis stacks 3 are connected in series.
• a conventional multi-series water electrolytic hydrogen production system is configured by electrically connecting water electrolysis stacks 3 in series.
• a power supply 12 is connected to both ends of the ten water electrolysis stacks 3 connected in series, and a voltage for the ten water electrolysis stacks is applied.
• the voltage for one water electrolysis stack is 0.5 kV
• a total voltage of 5.0 kV (0.5 kV/piece ⁇ 10 pieces) is applied to the entire ten water electrolysis stacks 3.
• a potential on the positive (+) side of a first one of the water electrolysis stacks 3 is 2.5 kV
• a potential on the negative (-) side of the first one of the water electrolysis stacks 3 is 2.0 kV.
• a potential on the positive (+) side of a tenth one of the water electrolysis stacks 3 is -2.0 kV
• a potential on the negative (-) side of the tenth one of the water electrolysis stacks 3 is -2.5 kV.
• Water (H 2 O) taken from outside through a water intake portion 4 is sent to a water supply portion 5 of the water electrolysis stack 3 by an electric motor 10 such as a water pump, and taken into the water electrolysis stack 3 through the water supply portion 5.
• Water (H 2 O) taken into the water electrolysis stack 3 is decomposed into hydrogen (H 2 ) and oxygen (O 2 ) by a water electrolysis reaction by a voltage (0.5 kV) corresponding to one water electrolysis stack applied to the water electrolysis stack 3, and is released outside through a hydrogen release portion 6 and an oxygen release portion 7, respectively.
• Oxygen (O 2 ) generated inside the water electrolysis stack 3 is released from the water electrolysis stack 3 as a mixture with water (H 2 O) which has not contributed to the reaction (O 2 , H 2 O), and therefore, after being separated into oxygen (O 2 ) and water (H 2 O) by a gas-liquid separator 11, oxygen (O 2 ) is released outside from the oxygen release portion 7, and water (H 2 O) is supplied inside of the water electrolysis stack 3 again through the water supply portion 5.
• an insulation 8 is disposed at a portion to which piping for supplying or releasing a fluid such as the water supply portion 5, the hydrogen release portion 6, and the oxygen release portion 7 is connected, and the water electrolysis stack 3 is insulated from outside except for an electrode portion to which the power supply 12 is connected.
• a portion other than the electrode portion to which the power supply 12 is connected is grounded (0 kV).
• a maximum potential difference of 2.5 kV with respect to the ground potential (0 kV) is generated in the first one of the water electrolysis stacks 3, and a maximum potential difference of -2.5 kV with respect to the ground potential (0 kV) is generated in the tenth one of the water electrolysis stacks 3.
• the insulation 8 in the water electrolysis stack 3 usually has an insulation performance capable of withstanding a selfgenerated voltage of 0.5 kV.
• FIG. 1 is a diagram showing a schematic configuration of a water electrolytic hydrogen production system 1 of the present embodiment.
• FIG. 2 is a diagram showing a structure of the water electrolysis stack 3 in FIG. 1 .
• FIG. 3 is a diagram illustrating a modification of the insulation member 9 in the water intake portion 4 in FIG. 1 .
• the water electrolytic hydrogen production system 1 of the present embodiment includes ten water electrolysis apparatuses 2 each having the water electrolysis stack 3.
• the water electrolysis stacks 3 of the water electrolysis apparatuses 2 are electrically connected to each other in series, and the power supply 12 is connected to an anode (positive electrode) side of a first water electrolysis stack 3 and a cathode (negative electrode) side of a tenth water electrolysis stack 3.
• Each of the water electrolysis apparatuses 2 mainly includes the water supply portion 5 that supplies water (H 2 O) to the water electrolysis stack 3, the water intake portion 4 that takes water (H 2 O) from outside into the water supply portion 5, the hydrogen release portion 6 that releases hydrogen (H 2 ) generated in the water electrolysis stack 3 to outside, the oxygen release portion 7 that releases oxygen (O 2 ) generated in the water electrolysis stack 3 to outside, and the gas-liquid separator 11 that separates a mixture (O 2 , H 2 O) of oxygen (O 2 ) and water (H 2 O) into oxygen (O 2 ) and water (H 2 O) .
• an insulation member 9 is disposed at a connecting portion of piping for supplying or releasing a fluid to or from the outside of the apparatus, the piping including the water intake portion 4, the hydrogen release portion 6, and the oxygen release portion 7.
• the water electrolysis stack 3 is held by fastening an electrolysis portion 13, power feed plates 15, and the insulation 8 integrally with end plates 14, and further includes a water supply port 16, a mixed discharge port 18, and a hydrogen outlet 17.
• the electrolysis portion 13 of the water electrolysis stack 3 includes a solid polymer film and a MEA (Membrane Electrode Assembly) in which an anode (positive electrode) and a cathode (negative electrode) are formed on both sides of the solid polymer film (none of them are shown), and water (H 2 O) is supplied to the anode (positive electrode) through the water supply port 16, and a current flows from one (left side in FIG. 2 ) of the pair of power feed plates 15 to the other (right side in FIG. 2 ), so that a water electrolysis reaction occurs in the electrolysis portion 13.
• MEA Membrane Electrode Assembly
• oxygen (O 2 ) generated at the anode (positive electrode) and water (H 2 O) that did not contribute to the reaction are released from the mixed discharge port 18 toward outside of the water electrolysis stack 3, and hydrogen (H 2 ) generated at the cathode (negative electrode) is released from the hydrogen outlet 17 to outside of the water electrolysis stack 3.
• pure water or ultrapure water having a specific resistance value of 1 to 10 M ⁇ cm or more is used as water (H 2 O) supplied from the water intake portion 4, and the specific resistance value of water in the water electrolytic hydrogen production system 1 is maintained by circulating the water through an ion exchange resin (not shown) in the system.
• the pair of power feed plates 15 and the electrolysis portion 13 of the water electrolysis stack 3 are electrically insulated from other constituent members such as the end plates 14 and pipes by the insulation 8.
• all the insulation members 9 can maintain sufficient insulation properties between inside and outside of the water electrolysis apparatus 2 even when a voltage of 5 kV, which is the difference between the maximum potential and the minimum potential of the water electrolysis stack 3, is applied.
• all the components inside the water electrolysis apparatus 2 are electrically insulated from outside by the insulation member 9 except for the power supply portion, and are electrically connected to the water electrolysis stack 3 weakly through water (H 2 O). Therefore, in each water electrolysis apparatus 2, the constituent members and the electrolysis portion 13 in the water electrolysis stack 3 are substantially equipotential.
• the potential on the anode (positive electrode) side of the water electrolysis stack 3 inside a first one of the water electrolysis apparatuses 2 is 2.5 kV, but a portion connected to the left side of the water electrolysis stack 3 such as the water supply portion 5 also has a potential of approximately 2.5 kV, and a portion connected to the right side of the water electrolysis stack 3 has a potential of 2.0 kV.
• the water intake portion 4 is configured by a water intake tank 19 having an air layer therein and an insulation member 20, and the amount of water taken from outside is controlled so that the water level in the water intake tank 19 is at a position equal to or lower than the insulation member 20, a situation where the water is electrically connected through water (H 2 O) is avoided.
• FIG. 4 is a diagram showing a schematic configuration of water electrolytic hydrogen production system 1 of the present embodiment.
• the water electrolytic hydrogen production system 1 of the present embodiment is different from that of the first embodiment ( FIG. 1 ) in that casings of all the water electrolysis apparatuses 2 are configured by insulation casings 21 instead of providing the insulation member 9 inside each of the water electrolysis apparatuses 2.
• Other configurations are the same as those of the first embodiment ( FIG. 1 ).
• the casings of all the water electrolysis apparatuses 2 are formed of an insulation member, and it is possible to maintain sufficient insulation properties even when the voltage of 5 kV, which is the difference between the maximum potential and the minimum potential of the water electrolysis stack 3, is applied between inside and outside of the water electrolysis apparatus 2.
• all the components inside the water electrolysis apparatus 2 are electrically insulated from outside by the insulation casing 21 of the water electrolysis apparatus 2, and are electrically connected to the water electrolysis stack 3 weakly through water (H 2 O). Therefore, in each water electrolysis apparatus 2, the constituent members and the electrolysis portion 13 in the water electrolysis stack 3 are substantially equipotential.
• a water electrolytic hydrogen production system according to a third embodiment of the present invention will be described with reference to FIGS. 5 and 6 .
• FIG. 5 is a diagram showing a schematic configuration of water electrolytic hydrogen production system 1 of the present embodiment.
• FIG. 6 is a diagram showing a structure of the water electrolysis stack 3 in FIG. 5 .
• the water electrolytic hydrogen production system 1 of the present embodiment is different from that of the first embodiment ( FIG. 1 ) in that, in addition to the configuration of the first embodiment ( FIG. 1 ), the water electrolysis stack 3 and the water supply portion 5 are electrically connected via a wiring 22 and the like. Other configurations are the same as those of the first embodiment ( FIG. 1 ).
• the water electrolysis stack 3 and the water supply portion 5 are electrically connected inside each of the water electrolysis apparatuses 2.
• FIG. 6 shows a specific connection portion between the water electrolysis stack 3 and the water supply portion 5.
• the power feed plate 15 on the anode (positive electrode) side is electrically connected to the water electrolysis stack 3 side, and the pipe (water supply port 16) near the connection portion with the water electrolysis stack 3 is electrically connected to the water supply portion 5 side.
• both ends of the insulation 8 inside the water electrolysis stack 3 are substantially equipotential.
• connection portion on the side of the water electrolysis stack 3 is sufficiently within the design range of the insulation 8 as long as it is either of the pair of power feed plates 15 and the electrolysis portion 13, and similar performance can be obtained, and thus, the connection portion does not exceed the scope of the present invention.
• the water intake portion 5 may be electrically connected to the power feed plate 15 or the electrolysis portion 13.
• FIG. 7 is a diagram showing a schematic configuration of water electrolytic hydrogen production system 1 of the present embodiment.
• the water electrolytic hydrogen production system 1 of the present embodiment is different from that of the first embodiment ( FIG. 1 ) in that, in addition to the configuration of the first embodiment ( FIG. 1 ), a potential setting portion 23 in which voltage sources that generate voltages equivalent to those of the respective water electrolysis stacks 3 are connected in series by the number that is less than the number of the water electrolysis stacks 3 by one is further provided.
• Other configurations are the same as those of the first embodiment ( FIG. 1 ).
• the potential setting portion 23 includes voltage sources for generating a voltage equal to that of the water electrolysis stacks 3 provided in the respective water electrolysis apparatuses 2 by the number that is less than the number of the water electrolysis apparatuses 2 (water electrolysis stacks 3) by one.
• the ten water electrolysis stacks 3 are connected in series, and the potential setting portion 23 includes nine voltage sources each generating a voltage of 0.5 kV.
• the voltage sources of the potential setting portion 23 are electrically connected to the water supply portions 5 of the water electrolysis apparatuses 2.
• the voltage between the water electrolysis stacks 3 is set, and both ends of the insulation 8 inside the water electrolysis stack 3 can be made substantially equipotential.
• the potential setting portion 23 can be configured by one voltage source and a plurality of (for example, nine) resistors, and equivalent performance can be obtained even for similar circuit deformation, and thus does not exceed the scope of the present invention.
• FIG. 8 is a diagram showing a schematic configuration of water electrolytic hydrogen production system 1 of the present embodiment.
• the water electrolytic hydrogen production system 1 of the present embodiment is different from that of the first embodiment ( FIG. 1 ) in that, in addition to the configuration of the first embodiment ( FIG. 1 ), an auxiliary machine power supply portion 24 that supplies power to an electric motor (water pump) 10 is further included separately from the power supply 12.
• an auxiliary machine power supply portion 24 that supplies power to an electric motor (water pump) 10 is further included separately from the power supply 12.
• Other configurations are the same as those of the first embodiment ( FIG. 1 ).
• the electric motor 10 such as a water pump is provided inside the water electrolysis apparatus 2, and is often driven at AC 200 V or AC 100 V.
• the casing of the electric motor 10 is connected to the components inside the water electrolysis apparatus 2 such as the water supply portion 5, the electric potential is substantially equal to that of the water electrolysis stack 3 in each water electrolysis apparatus 2. Therefore, when power is directly supplied from an external power supply to the electric motor 10, a large potential difference is generated between the external power supply and the housing of the electric motor 10.
• a power supply electrically insulated by a transformer 25 or the like is connected to the electric motor 10 such as a water pump.
• each transformer 25 To the coil on the primary side (AC power supply side in FIG. 8 ) of each transformer 25, 0.5 kV (the same voltage as that of the water electrolysis stack 3) is applied, and AC 200 V or AC 100 V (power supply voltage of the auxiliary machine) is generated in the coil on the secondary side (water electrolysis apparatus side in FIG. 8 ).
• FIG. 9 is a diagram showing a schematic configuration of water electrolytic hydrogen production system 1 of the present embodiment.
• FIG. 10 is a diagram showing a modification of the water electrolytic hydrogen production system 1 in FIG. 9 .
• the water electrolytic hydrogen production system 1 of the present embodiment is different from that of the first embodiment ( FIG. 1 ) in that the insulation member 9 is disposed in pipes between the water intake portion 4, the hydrogen release portion 6, and the oxygen release portion 7, and the water electrolysis stack 3 instead of being disposed in a connection portion of pipes that supply or release a fluid to and from outside of the apparatus.
• Other configurations are the same as those of the first embodiment ( FIG. 1 ).
• the insulation member 9 may be disposed in the vicinity of the water electrolysis stack 3 as shown in FIG. 9 .
• another insulation member 9 may be disposed in pipes between the water intake portion 4, the hydrogen release portion 6, and the oxygen release portion 7, and the water electrolysis stack 3.
• the insulation performance of the water electrolysis stack 3 can be further improved.
• FIG. 11 is a diagram showing a schematic configuration of the water electrolytic hydrogen production system 1 of the present embodiment.
• the water electrolytic hydrogen production system 1 of the present embodiment is different from that of the sixth embodiment ( FIG. 9 ) in that, in addition to the configuration of the sixth embodiment ( FIG. 9 ), the water electrolysis stack 3 and the water supply portion 5 are electrically connected via the wiring 22 and the like. Other configurations are similar to those of the sixth embodiment ( FIG. 9 ).
• the water electrolysis stack 3 and the water supply portion 5 are electrically connected.
• connection portion between the water electrolysis stack 3 and the water intake portion 4, the water supply portion 5, the hydrogen release portion 6, and the oxygen release portion 7 is the same as that of third embodiment ( FIG. 6 ). That is, the power feed plate 15 or the electrolysis portion 13 of the water electrolysis stack 3 is electrically connected to the water supply portion 5.
• both ends of the insulation 8 inside the water electrolysis stack 3 are substantially equipotential.
• the water electrolysis stack 3 may be electrically connected to any one of the insulation member 9 side portions of the water supply portion 5, the hydrogen release portion 6, and the oxygen release portion 7.
• the present invention is not limited to the above-described embodiments, and includes various modifications.
• the above-described embodiments have been described in detail in order to describe the present invention in an easy-to-understand manner, and are not necessarily intended to limit to those having all of the described configurations.
• a part of one configuration of a certain embodiment can be replaced with a configuration of a different embodiment, and a configuration of one embodiment can be added to a configuration of a different embodiment.

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• Inorganic Chemistry (AREA)
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• 2022
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