KR102610119B1 - Water management unit in hydrogen generating system using water electrolysis - Google Patents

Abstract

This invention is a device that is placed in the water circulation line of a hydrogen production system using water electrolysis and manages water by removing impurities generated during the electrolysis and circulation process of water. It is an agent that removes radicals generated during the electrolysis of water. It includes a first reaction tower (500) and a second reaction tower (600) that removes metal ions generated in the water circulation process, and the first reaction tower (500) acts as a radical scavenger on the carrier (511). It is configured to include a charge 510 consisting of a catalyst 512.

Description

Water management unit in hydrogen generating system using water electrolysis}

This invention relates to a hydrogen production system using water electrolysis (hereinafter referred to as water electrolysis). More specifically, in order to secure the durability of the water electrolysis stack (electrochemical reactor), it is placed in the water circulation line of the hydrogen production system to produce water. This relates to a device that manages water by removing radicals and metal ions, which are impurities generated during the electrolysis process and circulation process.

In general, there are various ways to produce hydrogen, but the method of obtaining hydrogen by electrolyzing water using a power source using renewable energy and water does not generate CO ₂ during the hydrogen production process, making it CO ₂ free hydrogen, or green. Hydrogen, under another name, has recently been in the spotlight.

Figures 1 to 3 show the basic principles, unit electrochemical cell, and electrochemical stack structure of a typical electrochemical cell (electrochemical reactor) that obtains hydrogen by electrolyzing water.

Figure 1 is a conceptual diagram of a membrane electrode assembly 100 that constitutes a part of a typical electrochemical cell that electrochemically decomposes water to produce hydrogen gas and oxygen gas. The membrane electrode assembly 100 is the core where the electrochemical reaction occurs. It is a component.

An electrochemical cell for electrolysis that produces oxygen gas (O ₂ ) and hydrogen gas (H ₂ ) by electrolyzing water (H ₂ 0) includes a first electrochemical reaction layer 104, a second electrochemical reaction layer ( 108), a film 106, a first diffusion layer 102, and a second diffusion layer 110. At this time, the first electrochemical reaction layer 104 is composed of a first electrochemical catalyst 112 and a first carrier 114, and the second electrochemical reaction layer 108 is composed of a second electrochemical catalyst 116 and It consists of a second carrier (118).

The first diffusion layer 102 and the second diffusion layer 110 assist the movement of electrons and reactants or products to (or in) the first and second electrochemical catalysts 112 and 116. The first and second electrochemical catalysts (112, 116) are the most important materials for electrolysis or generating electrical energy, and the first and second carriers (114, 118) are the first and second electrochemical catalysts (112, 116). 116) serves as a support and provides a path for electrons to move.

The first and second electrochemical catalysts 112 and 116 are mixed with the first and second carriers 114 and 118, a binder and a solvent to form a slurry or paste. After being made, it is applied to the film 106 or to the first and second diffusion layers 102 and 110 to form the first and second electrochemical reaction layers 104 and 108. At this time, the “electrochemical reaction layer (104, 108)-membrane 106” or “electrochemical reaction layer (104, 108)-membrane 106-diffusion layer (102, 110)” made in this way is used as a membrane electrode assembly ( 100) (Membrane Electrode Assembly, hereinafter referred to as “MEA”).

The gap between the first electrochemical reaction layer 104 and the second electrochemical reaction layer 108 formed in the MEA 100 has a physical film thickness value, and the first electrochemical reaction layer 104 and the second electrochemical reaction layer 108 Since there are no bubbles in the reaction layer 108, low voltage and high current operation is possible. In addition, since the conductivity of the electrolyte is not used as in an alkaline electrochemical cell, water as a raw material can be used at high purity, and thus high purity hydrogen and oxygen can be obtained.

Using the configuration shown in Figure 1, the process of electrolyzing water is explained as follows. Here, the place where the oxidation reaction occurs is the first electrochemical reaction layer 104, and the place where the reduction reaction occurs is the second electrochemical reaction layer 108, and the oxidation reaction and reduction reaction occur simultaneously.

First, when water (H ₂ 0) is supplied to the first electrochemical reaction layer 104 through the first diffusion layer 102, the water is supplied to the first electrochemical catalyst 112 (oxidation catalyst, positive electrode active material, and oxygen gas generation). At the pole (also called the pole), a decomposition reaction occurs into oxygen gas (O ₂ ), electrons (e ^- ), and hydrogen ions (H ⁺ ) (protons) as shown in Reaction Formula 1 below. At this time, oxygen gas (O ₂ ) flows out of the electrochemical cell (electrolysis cell) by diffusion, and hydrogen ions (H ⁺ ) pass through the membrane 106 by an electric field to form the second electrochemical catalyst (116). ) (also called reduction catalyst, negative electrode active material, hydrogen gas generation electrode), and the electrons (e ^- ) generated by the reaction are transferred from the first electrochemical catalyst 112 to the first diffusion layer 102 and the external circuit (not shown). It moves to the second diffusion layer 110 and the second electrochemical catalyst 116.

Meanwhile, in the second electrochemical catalyst 116, hydrogen ions (H ⁺ ) and electrons (e ^- ) moved from the first electrochemical catalyst 112 react to generate hydrogen gas (H ₂ ) as shown in Scheme 2. . Also, some of the water supplied to the first electrochemical reaction layer 104 moves to the second electrochemical reaction layer 108 by the electric field and flows out of the electrolysis cell together with hydrogen gas (H ₂ ).

The electrochemical reactions that occurred in the first electrochemical catalyst 112 and the second electrochemical catalyst 116 are expressed as Scheme 1 and Scheme 2 below, and the overall reaction (overall reaction) in the electrochemical cell is shown in Scheme 3 Same as

[Scheme 1]

2H ₂ O → 4H ⁺ + 4e ^- + O ₂ (anode)

[Scheme 2]

4H ⁺ + 4e ^- → 2H ₂ (cathode)

[Scheme 3]

2H ₂ O → O ₂ (anode) + 2H ₂ (cathode)

FIG. 2 is a structural diagram of a typical electrochemical cell that electrolyzes water using the MEA of FIG. 1. As shown in Figure 2, the electrochemical cell 200 includes a first end plate 202 (End Plate), a first insulating plate 204, a first current supply plate 206, and a first electrochemical reaction chamber frame. (208), first electrochemical reaction chamber 210, MEA (100 in FIG. 1), second electrochemical reaction chamber 212, second electrochemical reaction chamber frame 214, second current supply plate 216 ), a second insulating plate 218, and a second end plate 220, and there is a direct current power supply device as a power conversion device 224 that supplies current to the electrochemical cell.

The first end plate 202 and the second end plate 220 provide bolt/nut fastening holes (not shown) for unit electrochemical cell assembly, passages for reactants and products (not shown), and are a first insulating plate. (204) and the second insulating plate 218 are electrically connected between the first end plate 202 and the first current supply plate 206 and between the second end plate 220 and the second current supply plate 216, respectively. It has an insulating function, and the first current supply plate 206 and the second current supply plate 216 are connected to the power conversion device 224 and serve to supply the necessary current to the electrochemical cell 200.

Meanwhile, when the first electrochemical reaction layer 104 is located in the first electrochemical reaction chamber 210 and an oxidation reaction occurs, it becomes a space for the movement of water as a reactant and oxygen as a product, and forms a film 106. The second electrochemical reaction chamber 212, located centrally on the opposite side of the first electrochemical reaction chamber 210, is used for the movement of hydrogen generated by the reduction reaction and water moved from the first electrochemical reaction chamber 210. Space is provided.

The first electrochemical reaction chamber 210 is blocked from the outside by the first electrochemical reaction chamber frame 208, and the second electrochemical reaction chamber 212 is blocked from the outside by the second electrochemical reaction chamber frame 214. and is blocked. In addition, a gasket (or packing) 222 is installed between the MEA 100, the first electrochemical reaction chamber frame 208, and the second electrochemical reaction chamber frame 214 to prevent external leakage of reactants and products. .

Among the components constituting the electrochemical cell 200, the first electrochemical reaction chamber frame 208, the second electrochemical reaction chamber frame 214, and the gasket 222 are used to prevent the inflow of reactants or products through the electrochemical cell. It has an appropriate hole to facilitate outflow, and the first electrochemical reaction chamber frame 208 and the second electrochemical reaction chamber frame 214 have a flow path (dotted line in (a) of FIG. 2) for fluid (oxygen, hydrogen, water). (indicated by ) is formed.

Figure 3 is a conceptual diagram of a typical conventional electrochemical stack. In order to obtain the desired amount of product from an electrolysis reaction, a plurality of unit electrochemical cells are required, and in this case, a collection of two or more electrochemical cells stacked is called an electrochemical stack.

As shown in FIG. 3, when electrochemical cells are stacked to form the electrochemical stack 300, a desired number of unit electrochemical cells are repeatedly installed between the basic electrochemical cells 200. In the electrochemical stack, unit electrochemical cells are assembled by combining bolts 306 and nuts 310 through holes formed at the edges of the first and second end plates 202 and 220.

A bipolar plate 304 in which the first electrochemical reaction chamber frame 208 and the second electrochemical reaction chamber frame 214 of FIG. 2 are integrated is applied to the electrochemical stack 300. The bipolar plate 304 is an integrated plate and functions as an anode chamber and a cathode chamber.

Figure 4 is a diagram showing a system for producing hydrogen by electrolyzing water using an electrolysis stack of the same concept as the electrochemical stack of Figure 3. The hydrogen production system 400 shown in FIG. 4 includes an electrolysis stack 420, a water treatment unit that processes the water supplied to the electrolysis stack 420, and purification of hydrogen gas generated in the electrolysis stack 420. It consists of a gas processing unit that controls pressure.

Water, which is the raw material used in the electrolysis stack 420, is pure water of 1 Mega ohm cm or higher. Pure water is supplied by controlling the automatic valve 402 installed in the pure water supply line (s1), and the automatic valve 402 is controlled by It is controlled by the level sensor 405 for detecting the water level of the oxygen-water separation tank 404 (dotted line e2). Water in the oxygen-water separation tank 404 is supplied to the electrolysis stack 420 by the circulation pump 406 installed in the circulation pipe s2, and is circulated in the hydrogen-water separator 424 through a circulation line s9. It is combined with a heat exchanger (408), a water quality sensor (410), and an ion exchange filter (412) installed through pipes to the first electrochemical reaction chamber (414, where the oxidation reaction occurs) of the electrolysis stack (420). supplied. Meanwhile, when direct current is supplied from the power conversion device 440 to the electrolysis stack 420 through the wire e1, a water decomposition reaction occurs.

The oxygen and unreacted water generated in the first electrochemical reaction chamber 414 are moved to the oxygen-water separation tank 404 through the discharge pipe s4, and the discharge pipe s4 is equipped with a temperature sensor 416 that monitors the temperature. ) is installed. The oxygen separated in the oxygen-water separation tank 404 is discharged to the outside through the oxygen discharge pipe s5, and the water goes through a recirculation process.

The hydrogen gas generated in the second electrochemical reaction chamber 422 is accompanied by water, and is moved through the discharge pipe s6 to the hydrogen-water separation tank 424, where the gas and water are separated. The hydrogen-water separation tank 424 is equipped with a level sensor 426 for detecting the water level to control the water level. If the water level in the hydrogen-water separation tank 424 exceeds a certain value, the automatic valve 428 opens (electrical signal e3) and the water is supplied to the circulation pipe (s2) through the circulation line (s9).

Meanwhile, the hydrogen gas separated in the hydrogen-water separation tank 424 is supplied to the hydrogen gas purifier 430 through the gas pipe s7 to remove moisture contained in the hydrogen. Generally, the hydrogen gas purifier 430 uses a bed filled with a desiccant. Hydrogen that has passed through the hydrogen gas purifier 430 is supplied to sites requiring hydrogen through the high-purity hydrogen gas pipe (s8). At this time, the high-purity hydrogen gas pipe s8 has a pressure control valve 434 that regulates the pressure of hydrogen, so that the pressure of hydrogen gas generated in the electrolysis stack 420 is controlled. Pressure sensors 432 and 438 that measure pressure are installed at the front and rear ends of the pressure control valve 434, and a check valve 436 is installed to maintain the flow of gas in a certain direction.

As described above, securing the long-term durability of the electrolysis stack 420, which is a core process in the process of producing hydrogen by electrolyzing water, is an important factor in lowering the hydrogen production price and system price.

Ka Hung Wong and Erik Kjeang, "The Electrochemical Society Macroscopic In-Situ Modeling of Chemical Membrane Degradation in Polymer Electrolyte Fuel Cells", Journal of The Electrochemical Society, 161 (9) F823-F832 (2014) Journal of Power Sources, Vol. 420, 54-62, 2019 Frensch SH, Serre G, Fouda-Onana F, Jensen HC, Christensen ML, Araya SS, Kaer SK DOI, "Impact of iron and hydrogen peroxide on membrane degradation for polymer electrolyte membrane water electrolysis: Computational and experimental investigation on fluoride emission", Journal of Power Sources, Vol.420, 54-62, 2019 Dae-jin Yoon, Yeon-seon Oh, Hyun Seo, Sang-bong Moon, and Jang-hoon Jeong, "Manufacturing and performance study according to ceria content of covalent cross-linked SPEEK/Cs-TSiA membrane for water electrolysis", Trans. of the Korean Hydrogen and New Energy Society (2015. 6), Vol. 26, no. 3, pp. 212~220 Zhiyan Rui, JianguoLiu, "Review Understanding of free radical scavengers used in highly durable proton exchange membranes", Progress in Natural Science: Materials International, Vol. 30, 2020, pp.732-742

This invention is placed in the water circulation line of a hydrogen production system using water electrolysis to ensure the durability of the water electrolysis stack (electrochemical reactor) to remove radicals and metal ions, which are impurities generated during the electrolysis and circulation process of water. The purpose is to provide a device for managing water.

This invention to achieve the above object is a device that is placed in the water circulation line of a hydrogen production system using water electrolysis and manages water by removing impurities generated during the electrolysis process and circulation process of water. It includes a first reaction tower that removes radicals generated in the reactor, and a second reaction tower that removes metal ions generated in the water circulation process, wherein the first reaction tower consists of a radical scavenger catalyst on a carrier. Characterized in that it contains a filler.

Additionally, according to this invention, the first reaction tower and the second reaction tower may be connected in series or parallel.

Additionally, according to this invention, the metal ion is preferably Fe ²⁺ or Cu ²⁺ ion.

Additionally, according to this invention, the carrier may be composed of any one of titanium oxide, carbon black, graphite, graphite, activated carbon, carbon fiber, carbon nanotube, fullerene, titanium carbide, silica gel, alumina, or other inorganic porous materials. there is.

Additionally, according to this invention, the radical scavenger catalyst is preferably CeO2, _ZrO2 , or a composite oxide thereof.

In addition, according to this invention, it is more preferable that the amount of the radical scavenger catalyst is in the range of 1 to 5% by weight relative to the weight of the carrier.

Additionally, according to this invention, the second reaction tower may include chelate resin.

This invention has the advantage of lowering the hydrogen production cost when producing hydrogen by securing the durability of the device by removing impurities that affect durability during long-term operation in the water electrolysis process. In other words, this invention is placed in the water circulation line of the hydrogen production system to remove radicals and metal ions, which are impurities generated during the electrolysis and circulation process of water, and secure the durability of the water electrolysis stack (electrochemical reactor) to produce hydrogen during hydrogen production. Manufacturing costs can be reduced.

Figure 1 is a conceptual diagram of an MEA, which is part of a typical electrochemical cell that electrochemically decomposes water to produce hydrogen gas and oxygen gas.
FIG. 2 is a structural diagram of a typical electrochemical cell that electrolyzes water using the MEA of FIG. 1.
Figure 3 is a conceptual diagram of a typical conventional electrochemical stack.
FIG. 4 is a diagram showing a system for producing hydrogen by electrolyzing water using the electrochemical stack of FIG. 3.
Figure 5 is a diagram showing a hydrogen production system using water electrolysis equipped with a water management device according to an embodiment of the present invention.
FIG. 6 is a conceptual diagram of the first reaction tower shown in FIG. 5.
Figure 7 is a structural diagram of the filling shown in Figure 6.
Figure 8 is a diagram showing a hydrogen production system using water electrolysis equipped with a water management device according to another embodiment of the present invention.
Figure 9 is a graph comparing the performance of Invention Example 1, Invention Example 2, and Comparative Example 1 according to this invention.

Hereinafter, with reference to the attached drawings, preferred embodiments by which a person skilled in the art can easily implement this invention will be described in detail. However, in explaining in detail the operating principle of the preferred embodiment of this invention, if it is judged that a detailed description of a related known function or configuration may unnecessarily obscure the gist of this invention, the detailed description will be omitted. In addition, the same reference numerals are used for parts that perform similar functions and actions throughout the drawings.

Figure 5 is a diagram showing a hydrogen production system using water electrolysis equipped with a water management device according to an embodiment of the present invention. As shown in FIG. 5, the water management device according to an embodiment of the present invention is disposed in the water circulation line of the hydrogen production system (400A) configured with the same concept as FIG. This is to manage water by removing impurities that affect the durability of the stack (electrochemical reactor). Therefore, in this embodiment, the description of the hydrogen production system having the same concept as that of FIG. 4 will be omitted and the same or similar reference numerals will be used.

As shown in FIG. 5, the water management device of this embodiment is configured to remove radicals generated during the electrolysis of water and metal ions generated during the water circulation process. That is, the water management device of this embodiment includes a first reaction tower 500 for removing radicals generated within the water electrolysis stack (FIG. 3), and Fe ²⁺ or Cu generated within the hydrogen production system (FIG. 4). A second reaction tower (600) is provided to remove ²⁺ ions, and the first reaction tower (500) and the second reaction tower (600) are provided in series. Here, it is preferable that the second reaction tower (adsorption tower) 600 uses a chelate resin that is generally used to remove commercially available heavy metals.

In order to confirm the necessity of developing a water management device according to this invention, the OH radical generation process will first be described as follows.

Oxygen gas (O ₂ ) and hydrogen ions (H ⁺ ) generated at the anode of the electrolysis cell generate hydrogen peroxide (H ₂ O ₂₎ (Reaction Scheme 4), and hydrogen peroxide is produced from the pipe (made of metal) of the hydrogen production system in Figure 4. It reacts with eluted Fe ²⁺ or Cu ²⁺ to generate OH radicals that affect the durability of the membrane 106 (cation exchange membrane) of FIG. 1 (Reaction Scheme 5). The OH radical generation reaction is known as the Fenton reaction.

[Scheme 4]

O ₂ + 2H ⁺ + 2e ^- → H ₂ O ₂

[Scheme 5]

H ₂ O ₂ + Fe ²⁺ → Fe ³⁺ + HO ^· + HO ^-

It is known that the OH radicals generated by Scheme 5 attack the polymer film 106 in the MEA of FIG. 1, a key component of the electrochemical cell, thereby weakening its durability.

FIGS. 6 and 7 are for removing OH radicals generated by Reaction Scheme 5. FIG. 6 is a conceptual diagram of the first reaction tower shown in FIG. 5, and FIG. 7 is a structural diagram of the charger shown in FIG. 6.

As shown in FIG. 6, the first reaction tower 500 is configured similarly to a commonly used water purification tower, and is composed of a charge 510 and a barrier 520 to prevent the charge 510 from leaking out. It is composed. Meanwhile, the filler 510 is composed of a catalyst 512 for a radical scavenger on a carrier 511, as shown in FIG. 7. As the carrier 511, titanium oxide, carbon black, graphite, graphite, activated carbon, carbon fiber, carbon nanotube, fullerene, titanium carbide, silica gel, alumina or other inorganic porous materials are used, and preferably have regular and fine pores. A titanium-based inorganic material having a structure is suitable. Meanwhile, the carrier 610 preferably has a particle diameter of 0.02 mm or more.

The radical scavenger catalyst 512 applied on the carrier 511 is preferably CeO2, _ZrO2 , or their composite oxides. The amount of radical scavenger catalyst 512 applied on the carrier 511 is preferably in the range of 1 to 5% by weight relative to the weight of the carrier 511. This is because at 1% by weight or less, the radical removal rate becomes low, and at 5% by weight or more, this is the inflection point where the radical removal amount becomes constant.

The process of forming the radical scavenger catalyst 512 on the carrier 511 can be obtained by mixing the carrier and the precursor, adsorbing the precursor on the carrier, and then sintering. The reaction formula for this process is as follows.

[Scheme 6]

Ce(NO ₃ ) ₃ 6H ₂ O (CeCl ₃ or CeCl ₄ )→ CeO ₂ + NO _x

The thermal decomposition temperature for Scheme 6 is preferably 225 to 400°C. This is because it is difficult to obtain CeO ₂ crystallinity below 225°C, and metal crystallinity is obtained above 400°C, which reduces catalytic activity.

Figure 8 is a diagram showing a hydrogen production system using water electrolysis equipped with a water management device according to another embodiment of the present invention. As shown in FIG. 8, the water management device according to this embodiment is installed in the hydrogen production system 400B configured with the same concept as FIG. 4, but includes a first reaction tower 500 having the same configuration relationship as above. The second reaction tower 600 is configured in parallel.

Below, the results according to embodiments of this invention will be described.

[Invention Example 1]

After manufacturing and evaluating the electrochemical cell for hydrogen production, it was applied to the hydrogen production system (400A) shown in FIG. 5.

(1) Manufacturing process of MEA (100)

It consists of a formation process of the first and second electrochemical reaction layers 104 and 108, a formation process on the film 106, an ink manufacturing process, an ink transfer process, and a thermocompression process.

(1-1) Synthesis process of first and second electrochemical catalysts (112, 116)

The first and second electrochemical catalysts 112 and 116 used commercially available Pt/C (Premetek, 30% platinum support).

(1-2) Ink manufacturing process of the first and second electrochemical catalysts (112, 116)

Pt/C (Premetek, 30% platinum support) was used as an electrochemical catalyst (112, 116), and Nafion solution (registered product, DuPont) was used as a binder. The used catalyst and Nafion solution were mixed in isopropyl alcohol solvent at a ratio of 1:7.5 relative to the solid weight. To disperse the catalyst, stirring and ultrasonic waves were alternately applied twice for 1 hour each.

(1-3) Transfer process of the first and second electrochemical catalysts (112, 116)

(1-2) The ink obtained in the process was transferred to a syringe dedicated for electrospinning, transferred to a carbon sheet, and dried at 90°C for 30 minutes in an air atmosphere to produce an electrochemical reaction layer. The thickness of the electrochemical reaction layer was adjusted so that the oxide catalyst loading amount was about 1 mg/cm2.

(1-4) Heat compression process

The electrochemical catalysts 112 and 116 prepared above were thermocompressed on the surfaces of one side and the opposite side of the membrane 106, respectively, at a condition of 120°C and a pressure of 10 MPa for 2 minutes to obtain MEA (100). .

(2) Configuration of water electrolysis system

After manufacturing the MEA according to the above procedure, a 1NM ³ H ₂ /hr electrochemical cell (or stack, 300) was manufactured, and a system 400 for producing hydrogen by electrolyzing water using the stack was configured as shown in FIG. did.

(3) Water purification process configuration

(3-1) Fabrication of the first reaction tower (500)

The carrier 511 used for the filling 510 was titanium oxide (P25, manufactured by Degussa), which has excellent durability. The purchased carrier was left in weak acid (sulfuric acid, 1Mole) and then washed with pure water. As a radical scavenger catalyst (512) applied on the carrier, 5% by weight of CeO ₂ and ZrO ₂ composite was applied. The molar ratio of CeO ₂ and ZrO ₂ formed on the carrier was 90:10.

The preparation consisted of a carrier (95% by weight) and CeO _{2 and} ZrO ₂ precursors CeCl ₄ and ZrCl ₄ in molar ratio, mixed with IPA, dried at 80°C overnight, and then sintered at 400°C for 2 hours to obtain a filler. The obtained charge was filled into the reaction tower to produce a first reaction tower.

(3-2) Fabrication of the second reaction tower (600)

Bio-rad's Chelex 100 for removing Fe ²⁺ or Cu ²⁺ ions was selected and applied.

(3-3) Process composition

As shown in Figure 5, the first reaction tower 500 and the second reaction tower 600 were operated in series.

(4) Evaluation method

The temperature of the electrochemical cell (or stack, 300) and system (400A) was maintained at 50°C (temperature sensor 416 in Figure 5), and the current density was 3A/cm ² (typical current density 1A/cm ² ), accelerating durability. The evaluation was performed and is shown in Figure 9.

[Invention Example 2]

After manufacturing and evaluating the electrochemical cell for hydrogen production, it was applied to the hydrogen production system (400B) shown in FIG. 8.

(1) Manufacturing process of MEA (100): The same as Invention Example 1 was applied.

(2) Configuration of water electrolysis system: The same was applied as Invention Example 1.

(3) Water purification process configuration

(3-1) Fabrication of the first reaction tower (500): The same method as Invention Example 1 was applied.

(3-2) Fabrication of the second reaction tower (600): The same method as Invention Example 1 was applied.

(3-3) Process configuration: As shown in FIG. 8, the first reaction tower (500) and the second reaction tower (600) were operated in parallel.

(4) Evaluation method

The temperature of the electrochemical cell (or stack, 300) and system (400B) was maintained at 50°C (temperature sensor 416 in FIG. 8), and the current density was 3A/cm ² (typical current density 1A/cm ² ), accelerating durability. The evaluation was performed and is shown as Invention Example 2 in FIG. 9.

[Comparative Example 1]

After manufacturing and evaluating the electrochemical cell for hydrogen production, it was applied to the hydrogen production system 400 shown in FIG. 4.

(1) MEA (100) manufacturing process: The same as Invention Example 1 was applied.

(2) Configuration of water electrolysis system: The same was applied as Invention Example 1.

(3) Water purification process configuration: It was configured as a general process without the first reaction tower (500) and the second reaction tower (600).

(4) Evaluation method

The temperature of the electrochemical cell (or stack, 300) and system 400 was maintained at 50°C (temperature sensor 416 in FIG. 4), and the current density was 3A/cm ² (typical current density 1A/cm ² ), accelerating durability. The evaluation was performed and is shown in Figure 9 as Comparative Example 1.

[result]

Figure 9 is a graph comparing the performance of Invention Example 1, Invention Example 2, and Comparative Example 1 according to this invention, and shows a comparative evaluation of durability through accelerated operation of the water electrolysis stack.

As shown in Figure 9, Invention Example 1 (when the first and second reaction towers (500, 600) are operated in series) and Invention Example 2 (when the first and second reaction towers (500, 600) are operated in parallel) It was confirmed that the durability of Comparative Example 1 (when operating) was improved by more than 1.5 times compared to the durability (about 800 hours) of Comparative Example 1 (without the first and second reaction towers 500 and 600).

As can be seen from the above-described invention examples applying the above acceleration experiment results, when the first and second reaction towers 500 and 600 are applied to the water treatment process, the durability of the stack in the water electrolysis system is improved, This makes it possible to lower the hydrogen production price.

100: MEA 200: Electrochemical cell
300: Electrochemical stack 400, 400A, 400B: Hydrogen production system
500: first reaction tower 510: charger
511: Carrier 512: Radical scavenger catalyst
520: Preventer 600: Second reaction tower

Claims (7)

It is a device placed in the water circulation line of a hydrogen production system using water electrolysis to manage water by removing impurities generated during the electrolysis and circulation process of water.
A first reaction tower that removes radicals generated during the electrolysis of water,
It includes a second reaction tower that removes metal ions generated during the water circulation process,
A water management device in a hydrogen production system using water electrolysis, wherein the first reaction tower includes a charge composed of a radical scavenger catalyst on a carrier. In claim 1,
A water management device in a hydrogen production system using water electrolysis, characterized in that the first reaction tower and the second reaction tower are connected in series or parallel. In claim 1,
A water management device in a hydrogen production system using water electrolysis, wherein the metal ion is Fe ²⁺ or Cu ²⁺ ion. In claim 1,
Water electrolysis, characterized in that the carrier is composed of any one of titanium oxide, carbon black, graphite, graphite, activated carbon, carbon fiber, carbon nanotube, fullerene, titanium carbide, silica gel, alumina, or other inorganic porous materials. Water management device in hydrogen production system. In claim 4,
A water management device in a hydrogen production system using water electrolysis, wherein the radical scavenger catalyst is CeO2, _ZrO2 , or a composite oxide thereof. In claim 5,
A water management device in a hydrogen production system using water electrolysis, characterized in that the amount of the radical scavenger catalyst is in the range of 1 to 5% by weight relative to the weight of the carrier. In claim 1,
A water management device in a hydrogen production system using water electrolysis, wherein the second reaction tower includes a chelate resin.

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