KR20220095058A - Hydrogen purification apparatus in hydrogen generating system using water electrolysis - Google Patents

Abstract

The present invention relates to a hydrogen purification apparatus (500) in a hydrogen generating system using water electrolysis, which comprises: a mixer (501) which receives and heat-exchanges hydrogen containing moisture; a first adsorber (503) which receives hydrogen, from which a portion of moisture is removed after being cooled by the mixer, and completely adsorbs and removes moisture to increase the purity of hydrogen; a second adsorber (515) which receives a portion of the hydrogen purified by the first adsorber, drops the pressure thereof, and desorbs moisture adsorbed onto an adsorbent so that the supplied hydrogen contains moisture; an electrochemical hydrogen compressor (519) which compresses hydrogen containing low pressure and moisture by the second adsorber to a high pressure; a cooler (520) which cools the hydrogen compressed to high pressure by the electrochemical hydrogen compressor; and a water remover (521) which removes a portion of the moisture contained in the hydrogen cooled by the cooler and then supplies the same to the mixer. According to the present invention, it is possible to compress high-purity hydrogen to high pressure with low energy using an electrochemical hydrogen compressor.

Description

Hydrogen purification apparatus in hydrogen generating system using water electrolysis

The present invention relates to a hydrogen production system using water electrolysis (hereinafter, water electrolysis), and more particularly, to a hydrogen purification apparatus for purifying the produced hydrogen, purifying the produced hydrogen, and compressing it to high pressure.

In general, there are various methods of producing hydrogen, but the method of obtaining hydrogen by electrolysis of water using a power source and water using renewable energy does not generate CO ₂ during the hydrogen production process, so CO ₂ free hydrogen, or green Hydrogen has recently been in the spotlight as another name.

In order to commercialize a water electrolysis system that electrolyzes water, it is necessary to lower the energy consumption (higher efficiency) and lower the cost of the elements constituting the system.

1 to 3 show the basic principle of a typical electrochemical cell (electrochemical reactor) for obtaining hydrogen by electrolysis of water, a unit electrochemical cell, and a stack structure for electrochemistry.

1 is a conceptual diagram of a membrane electrode assembly 100 constituting 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 of the electrochemical reaction. is a component

The electrochemical cell for electrolysis that electrolyzes water (H ₂ 0) to produce oxygen gas (O ₂ ) and hydrogen gas (H ₂ ) is 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 . In this case, 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 a second electrochemical catalyst 116 and and a second carrier 118 .

The first diffusion layer 102 and the second diffusion layer 110 assist in transport of electrons and reactants or products to (or to) the first and second electrochemical catalysts 112 and 116 . The first and second electrochemical catalysts 112 and 116 are the most important materials for electrolysis or for making electrical energy, and the first and second carriers 114 and 118 are the first and second electrochemical catalysts 112 and 118 116) 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, the first and second electrochemical reaction layers 104 and 108 are formed by coating on the film 106 or on the first and second diffusion layers 102 and 110 . 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 applied to the membrane electrode assembly ( 100) (Membrane Electrode Assembly, hereinafter referred to as "MEA").

The interval between the first electrochemical reaction layer 104 and the second electrochemical reaction layer 108 formed in the MEA 100 has a thickness value of a physical film, and the first electrochemical reaction layer 104 and the second electrochemical reaction layer 104 Since bubbles do not exist in the reaction layer 108 , it is possible to operate at a low voltage and a high current. In addition, since the conductivity of the electrolyte is not used as in the alkaline electrochemical cell, water as a raw material can be used with high purity, and there is an advantage in that high purity hydrogen and oxygen can be obtained.

A process of electrolyzing water using the configuration shown in FIG. 1 will be described 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 the 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, water is generated by the first electrochemical catalyst 112 (oxidation catalyst, positive electrode active material, oxygen gas) In the electrode), a decomposition reaction occurs into oxygen gas (O ₂ ), electrons (e ^- ), and hydrogen ions (H ⁺ ) (protons) as shown in Reaction Equation 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 and the second electrochemical catalyst 116 ) (reduction catalyst, negative electrode active material, also referred to as a hydrogen gas generating electrode), and electrons (e ^- ) generated by the reaction are transferred from the first electrochemical catalyst 112 to the first diffusion layer 102 and an external circuit (not shown). city) through the second diffusion layer 110 and the second electrochemical catalyst 116 .

On the other hand, 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 . And, 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 together with the hydrogen gas (H ₂ ) to the outside of the electrolysis cell.

The electrochemical reaction that occurred in the first electrochemical catalyst 112 and the second electrochemical catalyst 116, respectively, is expressed as Scheme 1 and Scheme 2 below, and the overall reaction (general reaction) in the electrochemical cell is 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 for electrolyzing water with the MEA of FIG. 1 . 2, the electrochemical cell 200 is a first end plate 202 (End Plate), a first insulating plate 204, a first current supply plate 206, 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 DC power supply as a power converter 224 for supplying current to the electrochemical cell.

The first end plate 202 and the second end plate 220 provide bolt/nut fastening holes (not shown) for assembling a unit electrochemical cell, and passages of reactants and products (not shown), and the 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. The insulating function is performed, and the first current supply plate 206 and the second current supply plate 216 are connected to the power converter 224 to supply current required to the electrochemical cell 200 .

On the other hand, when the first electrochemical reaction layer 112 is located in the first electrochemical reaction chamber 210 and an oxidation reaction occurs, it becomes a space for movement of water as a reactant and oxygen as a product, and the film 106 is In the second electrochemical reaction chamber 212 located on the opposite side of the first electrochemical reaction chamber 210 to the center, for the movement of hydrogen generated by the reduction reaction and the water moved in 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 externally by the second electrochemical reaction chamber frame 214 . and is blocked In addition, gaskets (or packings) 222 for preventing external leakage of reactants and products are installed between the MEA 100 and the first electrochemical reaction chamber frame 208 and the second electrochemical reaction chamber frame 214 , respectively. .

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 include the inflow of reactants or products through the electrochemical cell and It has an appropriate hole for easy outflow, and the first electrochemical reaction chamber frame 208 and the second electrochemical reaction chamber frame 214 have a fluid (oxygen, hydrogen, water) flow path (a dotted line in FIG. 2A) indicated by ) is formed.

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

As shown in FIG. 3 , when the 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, the unit electrochemical cells are assembled by coupling the bolt 306 and the nut 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 integral plate and has the functions of an anode chamber and a cathode chamber.

4 is a diagram illustrating a system for producing hydrogen by electrolyzing water using an electrolysis stack having the same concept as the electrochemical stack of FIG. 3 . The hydrogen generator system 400 shown in FIG. 4 purifies the hydrogen gas generated from the electrolysis stack 420, a water treatment unit for processing water supplied to the electrolysis stack 420, and the electrolysis stack 420, and It consists of a gas processing unit that controls the pressure.

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

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 a temperature sensor 416 for monitoring the temperature in the discharge pipe s4 ) is installed. Oxygen separated in the oxygen-water separation tank 404 is discharged to the outside through the oxygen discharge pipe s5, and the water undergoes a recirculation process.

The hydrogen gas generated in the second electrochemical reaction chamber 422 is accompanied by water, and is moved to the hydrogen-water separation tank 424 through the discharge pipe s6 to separate the gas and water. The hydrogen-water separation tank 424 is provided with a level sensor 426 for water level detection for water level control. If, when the water level in the hydrogen-water separation tank 424 exceeds a predetermined value, the automatic valve 428 is opened (electrical signal e3) and 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 a gas pipe s7 to remove moisture contained in hydrogen. In general, a bed filled with a desiccant is applied to the hydrogen gas purifier 430 . Hydrogen that has passed through the hydrogen gas purifier 430 is supplied to a site requiring hydrogen through a high-purity hydrogen gas pipe s8. At this time, there is a pressure control valve 434 for controlling the pressure of hydrogen in the high-purity hydrogen gas pipe (s8), so that the pressure of hydrogen gas generated in the electrolysis stack 420 is adjusted. Pressure sensors 432 and 438 for measuring pressure are installed at the front and rear ends of the pressure control valve 434 , and a check valve 436 for maintaining the flow of gas in a certain direction is installed.

Korean Patent Registration No. 10-1357146 Korean Patent Publication No. 10-2008-0032962

The present invention provides a hydrogen purification device capable of purifying hydrogen through a purification process that removes moisture contained in hydrogen produced in the water electrolysis process, and compressing high-purity hydrogen to high pressure with low energy using an electrochemical hydrogen compressor It is intended to

This invention for achieving the above object is a hydrogen purification device in a hydrogen production system using water electrolysis, a mixer for receiving and heat exchange with hydrogen containing moisture, and some moisture is removed after cooling through the mixer A first adsorber that receives the supplied hydrogen and completely adsorbs and removes moisture to increase the purity of hydrogen, and a portion of hydrogen purified from the first adsorber is supplied to lower the pressure and desorbed moisture adsorbed to the adsorbent. A second adsorber for containing water in hydrogen, an electrochemical hydrogen compressor for compressing low pressure and high pressure hydrogen containing water by the second adsorber, and cooling the hydrogen compressed to high pressure in the electrochemical hydrogen compressor It is characterized in that it comprises a cooler, and a water remover for supplying to the mixer after removing a portion of the water contained in the hydrogen cooled in the cooler.

In addition, according to the present invention, the electrochemical hydrogen compressor includes a membrane electrode assembly, and the membrane electrode assembly is formed on one side of the polymer electrolyte membrane and the polymer electrolyte membrane to cause oxidation reaction. It may include a chemical reaction layer, and a second electrochemical reaction layer formed on the other side of the polymer electrolyte membrane to undergo a reduction reaction.

In addition, according to the present invention, the first and second electrochemical reaction layers each include an electrochemical catalyst, and the electrochemical catalyst is a platinum group element of platinum, palladium, ruthenium, iridium, rhodium, and osmium, iron, lead, It may be composed of any one of copper, chromium, cobalt, nickel, manganese, vanadium, molybdenum, gallium and aluminum, alloys thereof, oxides and double oxides thereof.

In addition, according to the present invention, the electrochemical catalyst preferably has a particle diameter of 0.5 to 20 nm.

In addition, according to the present invention, the first and second electrochemical reaction layers each include a carrier, and the carrier is selected from any one of titanium oxide, carbon black, graphite, graphite, activated carbon, carbon fiber, carbon nanotube, and fullerene. can be configured.

In addition, according to the present invention, the carrier preferably has a particle diameter of 10 ~ 1,000 nm.

This invention has the advantage of purifying hydrogen through a purification process that removes moisture contained in hydrogen produced in the water electrolysis process, and compressing high-purity hydrogen at low energy and high pressure using an electrochemical hydrogen compressor. That is, the present invention has the advantage that it is possible to replace the mechanical compressor applied to the existing hydrogen purification process with an electrochemical hydrogen compressor, so that the device can be compact and energy cost can be reduced.

1 is a conceptual diagram of an MEA, which is a 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 for electrolyzing water with the MEA of FIG. 1 .
3 is a conceptual diagram of a conventional general electrochemical stack.
FIG. 4 is a view showing a system for producing hydrogen by electrolyzing water using the electrochemical stack of FIG. 3 .
5 is a detailed view of a hydrogen purification apparatus according to an embodiment of the present invention.
6 is a view showing the principle of the electrochemical hydrogen compressor shown in FIG.
7 is a graph showing the performance of Inventive Example 1 according to the present invention.
8 is a graph showing the performance of Inventive Example 2 according to the present invention.

Hereinafter, with reference to the accompanying drawings, a preferred embodiment in which a person of ordinary skill in the art to which this invention pertains can easily practice this invention will be described in detail. However, when it is determined that a detailed description of a related well-known function or configuration may unnecessarily obscure the gist of the present invention in describing the operating principle of the preferred embodiment of the present invention in detail, the detailed description thereof will be omitted. In addition, the same reference numerals are used for parts having similar functions and actions throughout the drawings.

This invention is an improvement of the hydrogen gas purifier 430 constituting the hydrogen generator system 400 shown in FIG. 4 , and its configuration will be described in detail below. 5 is a detailed view of a hydrogen purification apparatus according to an embodiment of the present invention.

A method of purifying hydrogen is to remove water present in hydrogen using an adsorption method, and a dual bed adsorption process is generally used. The bed on one side performs dehumidification, and the bed on the other side is configured to perform regeneration.

Silica gel, alumina, or other inorganic porous solid is used as the material used as the adsorbent, and preferably, zeolite or molecular sieve having a regular and fine pore structure is suitable for obtaining high hydrogen purity (99.999%). The regeneration process can be operated by using heat or by lowering the pressure, but it is preferable to use heat in consideration of the characteristics of the electrolysis device (low operating pressure and high pressure gas method applied).

The adsorption-regeneration process using the hydrogen purifier shown in FIG. 5 will be described as follows. In FIG. 5 , the red color indicates not being operated, and the blue color indicates the operating state.

[refining process]

Hydrogen (FIG. 4, s7) generated in the second electrochemical reaction chamber (FIG. 4, 422) and separated in the hydrogen-water separation tank (FIG. 4, 424) contains a temperature of 80°C and 0.1% moisture, this hydrogen is supplied along the line s501 and cooled through the mixer 501 having a heat exchanger (30° C.), the condensed moisture is removed from the moisture eliminator 522 through the line s502, and the moisture is removed Hydrogen is supplied to the first adsorber 503 (refining process) through the first solenoid valve 502 through the line s503, and the remaining moisture is completely removed (adsorbed) to increase the purity of hydrogen, and desired high-purity hydrogen (99.999) %) is obtained. As such, the purified hydrogen satisfies the product standard, and the second solenoid valve 504, the first flow control valve 505, the first manual control valve 506 and the sampling valve 521 along the line s505. It can be used through

[Regeneration process]

On the other hand, a portion of the hydrogen flowing along the line (s505) passes through the second flow control valve 511, the third solenoid valve 512, and the fourth solenoid valve 514, and operates at a high temperature of 200° C. or higher. It is supplied to the adsorber 515 (regeneration process) to desorb moisture adsorbed from the adsorbent. Therefore, in the second adsorber 515 (regeneration process), the pressure of the supplied hydrogen is lowered and the moisture adsorbed to the adsorbent is desorbed to contain moisture in the supplied hydrogen.

[Hydrogen cycle process]

Hydrogen flowing along the line s512 after going through the regeneration process through the second adsorber 515 (regeneration process) has a pressure drop and has a large amount of moisture and hydrogen. Considering economic feasibility, hydrogen circulation is required. . Hydrogen having such a low pressure and moisture has 0.1% moisture as it passes through the fifth solenoid valve 518, electrochemical hydrogen compressor 519, cooler 520 and moisture remover 512, and having this moisture Hydrogen is supplied to the mixer 501 along a line s513.

[Operation of solenoid valve]

In FIG. 5 , the purification process is a process of removing moisture in the first adsorber 503 (purification process), and the regeneration process is a process of regeneration in the second adsorber 515 (regeneration process). The third solenoid valve 512 is a valve that supplies hydrogen for regeneration and is always in an operating state. On the other hand, the solenoid valve has an On (operational) or Off (operational stop) status for each cycle, and the operating state is as follows.

If the first group is On, the second group is Off, and when the first group is Off, the second group is On. The first group of solenoid valves are a first solenoid valve 502 , a second solenoid valve 504 , a fourth solenoid valve 514 , and a fifth solenoid valve 518 . The solenoid valves of the second group are a sixth solenoid valve 517 , a seventh solenoid valve 516 , an eighth solenoid valve 513 , and a ninth solenoid valve 523 .

6 is a view showing the principle of the electrochemical hydrogen compressor shown in FIG. As shown in FIG. 6, the electrochemical hydrogen compressor of this embodiment (FIGS. 5 and 519) electrochemically compresses hydrogen to produce high-pressure hydrogen gas, and is configured similarly to the principle of the water electrolysis reaction of FIG. will be.

The hydrogen compressor ( FIGS. 5 and 519 ) of this embodiment compresses the hydrogen gas (H ₂ ) having moisture, and includes a membrane electrode assembly 600 (hereinafter referred to as “MEA”). The membrane electrode assembly 600 includes a first electrochemical reaction layer 620 , a second electrochemical reaction layer 630 , a film 610 , a first diffusion layer 602 , and a second diffusion layer 612 . The first electrochemical reaction layer 620 is composed of a first electrochemical catalyst 604 (red) and a first carrier 606 (gray), and the second electrochemical reaction layer 630 is a second electrochemical catalyst ( 614, blue) and a second carrier 616, gray.

The first diffusion layer 602 and the second diffusion layer 612 assist in transport of electrons and reactants or products to (or to) the first and second electrochemical catalysts 604 and 614 . The first and second electrochemical catalysts 604 and 614) are the most important materials for performing electrolysis, and the first and second carriers 606 and 616 are the first and second electrochemical catalysts 604 and 614. It serves as a support and provides a path for electrons to move.

The first and second electrochemical catalysts 604 and 614 are mixed with the first and second carriers 606 and 616, a binder and a solvent to form a slurry or paste. After being made, the first and second electrochemical reaction layers 620 and 630 are formed by coating on the film 610 or on the first and second diffusion layers 602 and 612 . At this time, the "electrochemical reaction layer 620, 630 - film 610" or "electrochemical reaction layer 620, 630 - film 610 - diffusion layer 602, 612" made in this way is applied to the membrane electrode assembly ( Membrane Electrode Assembly, hereinafter referred to as "MEA").

A process of compressing hydrogen using the configuration shown in FIG. 6 will be described as follows. A place where the oxidation reaction takes place is the first electrochemical reaction layer 620 , and the place where the reduction reaction takes place is the second electrochemical reaction layer 630 , and the electrochemical reaction takes place at the same time as the oxidation reaction and the reduction reaction.

First, when hydrogen and impurities (H ₂ , H ₂ O) are supplied to the first electrochemical reaction layer 620 through the first diffusion layer 602 , hydrogen is produced in the first electrochemical catalyst 604 with the following Reaction Equation 4 and It is also decomposed into electrons (e ^- ) and hydrogen ions (H ⁺ ) (protons). Hydrogen ions (H ⁺ ) pass through the membrane 610 by the electric field and move to the second electrochemical catalyst 614, and the electrons (e ⁻ ) generated in Scheme 4 are first in the first electrochemical catalyst 604 . It moves to the second diffusion layer 612 and the second electrochemical catalyst 614 through the first diffusion layer 602 and an external circuit (not shown).

On the other hand, in the second electrochemical catalyst 614, hydrogen ions (H ⁺ ) and electrons (e ^- ) moved from the first electrochemical catalyst 604 react to generate hydrogen gas (H ₂ ) as shown in Reaction Equation 5. .

When the electrochemical reaction that occurred in the first electrochemical catalyst 604 and the second electrochemical catalyst 614, respectively, is expressed, the following Reaction Schemes 4 and 5 are the same, and the overall reaction (general reaction) in the electrochemical cell is Scheme 6 same as

[Scheme 4]

H ₂ → 2H ⁺ + 2e ^- (anode)

[Scheme 5]

2H ⁺ + 2e ^- → H ₂ (cathode)

[Scheme 6]

(low pressure, positive) H ₂ → H ₂ (high pressure, negative)

The membrane 610 of this embodiment may be one having hydrogen ion (proton) conductivity, and a fluorine-based polymer electrolyte or a hydrocarbon-based polymer electrolyte may be used. At this time, as a fluorine-based polymer membrane, for example, DuPont's Nafion (Nafion, registered trademark), Asahi Glass's Flemion (Flemion, registered trademark), Asahi Kasei's Aciplex (Aciplex, registered trademark) ), Gore's Gore Select (registered trademark), etc. can be used, and hydrocarbon-based polymer membranes include sulfonated polyetherketone, sulfonated polyethersulfone, sulfonated polyetherethersulfone, sulfonated polysulfide, An electrolyte membrane such as sulfonated polyphenylene may be used. Among these, it is suitable to use DuPont's Nafion (registered trademark)-based material as the polymer film.

The first and second electrochemical reaction layers 620 and 630 of this embodiment are formed on both sides of the film 610, and are formed using catalyst ink. The catalyst ink for the first electrochemical reaction layer 620 includes at least a first electrochemical catalyst 604 , a first carrier 606 , a polymer electrolyte and a solvent, and a catalyst ink for the second electrochemical reaction layer 630 . The catalyst ink includes at least a second electrochemical catalyst 614 , a second carrier 616 , a polyelectrolyte and a solvent.

As the polymer electrolyte included in the catalyst ink of this embodiment, a fluorine-based polymer electrolyte having proton conductivity, a hydrocarbon-based polymer electrolyte, or the like may be used. In addition, as the fluorine-based polymer electrolyte, for example, DuPont's Nafion (registered trademark)-based material may be used, and as the hydrocarbon-based polymer electrolyte, sulfonated polyetherketone, sulfonated polyethersulfone, and sulfonated polyetherether An electrolyte such as sulfone, sulfonated polysulfide, or sulfonated polyphenylene may be used. Among them, in consideration of adhesion to the first and second electrochemical reaction layers 620 and 630 , it is preferable to use the same material as that of the film 610 .

The first and second electrochemical catalysts 604 and 614 used in this embodiment include platinum group elements such as platinum, palladium, ruthenium, iridium, rhodium, and osmium, iron, lead, copper, chromium, cobalt, nickel, manganese, and vanadium. , metals such as molybdenum, gallium, and aluminum, or alloys thereof, or oxides, double oxides, etc. may be used, but platinum, palladium, It is preferable to use one or more metals or oxides selected from rhodium, ruthenium and iridium.

In the first and second electrochemical catalysts 604 and 614 of this embodiment, if the particle size is too large, the activity of the catalyst decreases, and if the particle size is too small, the stability of the catalyst decreases. Therefore, the particle size is preferably 0.5 to 20 nm, , more preferably 1 to 5 nm.

Meanwhile, as the carriers (or carriers) 606 and 616 for supporting the catalyst, titanium oxide and carbon particles are used as electronically conductive powders. These carriers are fine particles, have conductivity, and do not interfere with the catalyst. However, titanium oxide, carbon black, graphite, graphite, activated carbon, carbon fiber, carbon nanotubes, and fullerene are used. It is preferable to be

In addition, when the particle diameter of the carriers 606 and 616 is too small, it becomes difficult to form an electron conductive path. Therefore, as for a particle diameter, 10-1,000 nm is preferable, More preferably, it is 10-100 nm.

Hereinafter, a method for manufacturing an MEA according to an embodiment of the present invention will be described.

First process: pretreatment process of the film 610

The film 610 is immersed in a metal precursor solution for a predetermined time and then undergoes a reduction process to form a metal thin film layer having an electron conduction function on the film 610 . At this time, the thickness of the metal thin film layer is formed by repeating the deposition reduction process. A detailed process for this will be described later.

Second process: forming process of first and second electrochemical reaction layers 620 and 630

The second process is a process of forming the first and second electrochemical reaction layers 620 and 630 on the film 610 obtained in the first process. A catalyst synthesis process, a catalyst ink manufacturing process, a catalyst ink transfer process, and thermocompression bonding consists of processes. The catalyst synthesis process is a process of obtaining a mixed oxide through a reaction between a precursor of a desired catalyst and an oxidizing agent, and drying it to obtain an electrochemical catalyst having a powder structure, and the catalyst ink manufacturing process is performed with the electrochemical catalyst synthesized in the catalyst synthesis process This is a process of manufacturing a catalyst ink in which powder, dispersant, and a binder made of the film 610 are mixed. In addition, the catalyst ink transfer process is a process in which the catalyst ink prepared in the catalyst ink manufacturing process is transferred onto a Teflon sheet using a spray or the like and then dried, and the thermocompression bonding process is a catalyst on both sides of the membrane 610 obtained in the first process. After fixing the Teflon sheet obtained in the ink transfer process, it is a process of thermocompression bonding using a hot press or the like. A detailed process for this will be described later.

The structure of the electrochemical cell uses FIG. 2 . The electrochemical cell of this embodiment includes a first endplate, a first insulating plate, a first electrochemical reaction chamber frame, a first electrochemical reaction chamber, an MEA, a second electrochemical reaction chamber, a second electrochemical reaction chamber frame, a second It is composed of an insulating plate and a second end plate, and a DC power supply is used as a power converter to drive the electrochemical cell.

Hereinafter, a method for manufacturing a membrane electrode assembly for an electrochemical hydrogen compressor according to the invention examples of this embodiment will be described in detail, and experimental results will be described. However, this invention is not limited to the following invention examples.

[Invention Example 1]

After the production and evaluation of the electrochemical cell for hydrogen compression, it was applied to the hydrogen generator system 400 and the hydrogen purifier 500 of FIG. 5 .

1. Manufacture of electrochemical hydrogen compressor using general MEA process

(1) MEA (600) manufacturing process for hydrogen compressor

The process of forming the first and second electrochemical reaction layers 620 and 630 is a process of forming on the film 610 of the first process, and includes an ink manufacturing process, an ink transfer process, and a thermocompression bonding process.

(1-1) Synthesis process of the first and second electrochemical catalysts 604 and 614

As the first and second electrochemical catalysts 604 and 614, commercially available Pt/C (Premetek Co., Ltd., platinum loading mass of 30%) was used.

(1-2) Ink manufacturing process of the first and second electrochemical catalysts 604 and 614

Pt/C (Premetek, 30% platinum loading) as the first and second electrochemical catalysts 604 and 614, and Nafion solution (registered product, DuPont) were used as binders. The catalyst and Nafion solution used were mixed in an isopropyl alcohol solvent in a ratio of 1:7.5 based on the solid weight. For dispersion of the catalyst, stirring and ultrasonic waves were alternately treated twice for 1 hour each.

(1-3) Transfer process of the first and second electrochemical catalysts 604 and 614

An electrochemical catalyst layer was prepared by transferring the ink obtained in step 1-2 to a dedicated syringe for electrospray, transferring it to a carbon sheet, and drying it at 90° C. for 30 minutes in an atmospheric atmosphere. The thickness of the electrochemical reaction layer was adjusted so that the oxide catalyst loading amount was about 1 mg/cm 2 .

(1-4) Thermocompression bonding process

The first and second electrochemical catalysts 604 and 614 prepared above are subjected to thermocompression treatment for 2 minutes at a pressure of 10 MPa under a condition of 120 ° C. MEA (600) as shown in 6 was obtained.

2. Electrochemical cell and evaluation system for evaluation

In constituting the electrochemical cell for evaluation, carbon fiber fibers were attached to the MEA of Invention Example 1 so as to be supported by the first and second diffusion layers 602 and 612 .

As in FIG. 4, hydrogen generated in the electrolysis cell (or stack) was separated in the hydrogen-water separator 424 and then supplied to the electrochemical hydrogen compressor, and the temperature was maintained at 50° C. (416 temperature sensor in FIG. 4). and the current-voltage of the electrolysis cell, the hydrogen input, and the pressure at the hydrogen outlet were measured.

3. Measurement result

7 shows the hydrogen compression effect and the energy consumption during compression for the electrochemical hydrogen compressor manufactured according to Invention Example 1, respectively. As can be seen from (a) of FIG. 7 , it can be seen that the hydrogen pressure of the negative electrode is higher than the hydrogen pressure of the positive electrode. This means that when the electrochemical hydrogen compressor manufactured according to Invention Example 1 is used, the hydrogen compression effect is excellent. In addition, as can be seen from (B) of FIG. 7 , it can be seen that the change of the voltage value according to the change of the current is constant. This means that when the electrochemical hydrogen compressor manufactured according to Invention Example 1 is used, the electric energy consumption is constant, so that hydrogen can be compressed with low energy and high pressure.

[Invention Example 2]

1. Fabrication of an electrochemical hydrogen compressor using the MEA process in which a platinum layer is directly formed on a membrane

go. MEA (600) manufacturing

(1) First process: The film 610 is immersed in a platinum chloride ((NH ₃ ) ₄ PtCl ₂ *H ₂ O) precursor solution for 5 hours. The polymer electrolyte membrane that has undergone the deposition process is washed with pure water, and a NaBH ₄ solution is applied to reduce the metal precursor. The polymer electrolyte membrane having the reduced electron layer is treated by immersion in NaOH solution at 90° C. for 1 hour, then washed again with pure water.

2. Electrochemical cell and evaluation system for evaluation

Evaluation was carried out in the same manner as in Invention Example 1.

3. Measurement result

8 shows the hydrogen compression effect and the energy consumption during compression for the electrochemical hydrogen compressor manufactured according to Inventive Example 2, respectively. As can be seen from (A) of FIG. 8, it can be seen that the hydrogen pressure of the negative electrode is higher than the hydrogen pressure of the positive electrode. This means that when the electrochemical hydrogen compressor manufactured according to Inventive Example 2 is used, the hydrogen compression effect is excellent. Also, as can be seen from (B) of FIG. 8 , it can be seen that the change of the voltage value according to the change of the current is constant. This means that when the electrochemical hydrogen compressor manufactured according to Invention Example 2 is used, the electric energy consumption is constant, so that hydrogen can be compressed with low energy and high pressure.

As can be seen from the above-described inventions, in this invention, when an electrochemical hydrogen compressor is used, hydrogen can be compressed at a high pressure with low energy. It is possible to replace the mechanical compressor applied to the existing hydrogen purification process with the electrochemical hydrogen compressor of the present invention, thereby making it possible to compact the device and reduce energy costs.

In the above, the technical details of the hydrogen purification apparatus in the hydrogen production system using water electrolysis of the present invention have been described along with the accompanying drawings, but this is an exemplary description of the best embodiment of the present invention. Accordingly, the present invention is not limited to the above-described embodiments, and it is apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention, such modifications Examples or modifications will also fall within the scope of the claims of this invention.

500: hydrogen purification device 501: mixer
503: first adsorber 515: second adsorber
519: electrochemical hydrogen compressor
520: cooler 521: moisture remover
600: MEA 602: first diffusion layer
604: first electrochemical catalyst 606: first carrier
610: film 612: second diffusion layer
614: second electrochemical catalyst 616: second carrier
620: first electrochemical reaction layer 630: second electrochemical reaction layer

Claims (6)

As a hydrogen purification device in a hydrogen production system using water electrolysis,
A mixer that receives and heat exchanges hydrogen containing moisture,
A first adsorber that receives hydrogen from which some moisture has been removed after being cooled through the mixer to completely adsorb and remove moisture to increase the purity of hydrogen;
a second adsorber for receiving a portion of the purified hydrogen from the first adsorber and lowering the pressure and desorbing the water adsorbed on the adsorbent to contain water in the supplied hydrogen;
an electrochemical hydrogen compressor for compressing low pressure and moisture-containing hydrogen to high pressure by the second adsorber;
A cooler for cooling the hydrogen compressed to high pressure in the electrochemical hydrogen compressor, and
Hydrogen purification apparatus comprising a water remover for supplying to the mixer after removing a portion of the water contained in the hydrogen cooled in the cooler. The method according to claim 1,
The electrochemical hydrogen compressor includes a membrane electrode assembly,
The membrane electrode assembly includes a polymer electrolyte membrane, a first electrochemical reaction layer formed on one side of the polymer electrolyte membrane to cause an oxidation reaction, and a second electrochemical reaction layer formed on the other side of the polymer electrolyte membrane to undergo a reduction reaction Hydrogen purification apparatus, characterized in that. 3. The method according to claim 2,
The first and second electrochemical reaction layers each include an electrochemical catalyst,
The electrochemical catalyst is platinum, palladium, ruthenium, iridium, rhodium, platinum group elements of osmium, iron, lead, copper, chromium, cobalt, nickel, manganese, vanadium, molybdenum, any one metal of gallium and aluminum, alloys thereof , A hydrogen purification apparatus characterized in that it consists of any one of an oxide and a double oxide. 4. The method according to claim 3,
The electrochemical catalyst is a hydrogen purification apparatus, characterized in that having a particle diameter of 0.5 ~ 20㎚. 3. The method according to claim 2,
The first and second electrochemical reaction layers each include a carrier,
The carrier is a hydrogen purification apparatus, characterized in that consisting of any one of titanium oxide, carbon black, graphite, graphite, activated carbon, carbon fiber, carbon nanotubes and fullerene. 6. The method of claim 5,
The carrier is hydrogen purification apparatus, characterized in that it has a particle diameter of 10 ~ 1,000㎚.

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