Apparatus and method for producing hydrogen and electric power

Abstract

A hydrogen and power production apparatus according to one aspect of the present invention comprises a unit cell comprising a cathode, an anode, and a ceramic membrane, which is an oxygen ion conductor, disposed between the cathode and the anode, wherein a by-product gas containing carbon monoxide is supplied to the anode, water is supplied to the cathode, hydrogen is generated at the cathode of the unit cell by an electrochemical reaction of the water, and electric power can be generated in an external circuit electrically connecting a cathode-side current collector and an anode-side current collector of the unit cell.

Description

Hydrogen and power generation device and production method

[0001] The present invention relates to a hydrogen and power generation device and a method for production, and more specifically, to a hydrogen and power generation device and a method for production that enables the simultaneous production of hydrogen and power and allows the amount of hydrogen produced to be controlled.

[0002] Representative hydrogen production technologies include water-methane reforming, coal gasification, water electrolysis, and biomass gasification. However, water-methane reforming has limitations due to the generation of large amounts of carbon dioxide, and coal gasification also poses a significant environmental burden. While water electrolysis is receiving considerable attention as an eco-friendly method for the commercial production of hydrogen, a clean energy source, it still faces difficulties in commercialization due to its low hydrogen production per unit area.

[0003] Meanwhile, thermochemical cycle technology is a technology that simultaneously produces hydrogen and electricity. Thermochemical cycle technology utilizes chemical intermediate reactants to decompose water in multiple stages to produce hydrogen and oxygen, and generates electricity by utilizing the high-temperature thermal energy produced during this process.

[0004] Hydrogen production and power generation technologies have developed as independent technologies, remaining at the level of generating electricity by converting the thermal energy produced during hydrogen production into mechanical energy or by consuming hydrogen as a raw material.

[0005] According to one embodiment of the present invention, a production apparatus and a production method capable of producing both hydrogen and electricity may be provided.

[0006] According to another embodiment of the present invention, a production apparatus and a production method capable of controlling the production amount of hydrogen may be provided.

[0007] The problems of the present invention are not limited to those described above. A person skilled in the art to which the present invention pertains will have no difficulty understanding additional problems of the present invention from the overall contents of this specification.

[0008] A hydrogen and power generation device according to one embodiment of the present invention comprises a unit cell including a cathode, an anode, and a ceramic membrane which is an oxygen ion conductor interposed between the cathode and the anode, wherein a byproduct gas containing carbon monoxide is supplied to the anode and water is supplied to the cathode, hydrogen is generated by an electrochemical reaction of the water at the cathode of the unit cell, and power is generated in an external circuit that electrically connects the cathode-side current collector and the anode-side current collector of the unit cell.

[0009] In one embodiment, the unit cell is flat, and the production device may include a stack in which a separator, a current collector, a unit cell, and a current collector are sequentially and repeatedly stacked.

[0010] In one embodiment, the byproduct gas may include byproduct gas generated at a steel mill.

[0011] In one embodiment, the external circuit may further include a current control unit that controls the amount of current flowing between the cathode-side current collector and the anode-side current collector.

[0012] In one embodiment, the amount of hydrogen generated at the cathode can be controlled by the current control unit.

[0013] In one embodiment, the ceramic membrane may comprise gadolinium-doped ceria (CGO), samaria-doped ceria (SDC), yttria-stabilized zirconia (YSZ), lanthanum-strontium-gallate-magnesite (LSGM), scandia-stabilized zirconia (SSZ), cerium-doped zirconia, or a mixture thereof or a composite thereof.

[0014] A method for producing hydrogen and electricity according to one embodiment of the present invention supplies a gas containing water to a cathode that is electrically connected to an anode by an external circuit to produce hydrogen by an electrochemical reaction of water, and supplies a byproduct gas containing carbon monoxide to the anode to generate carbon dioxide and electrons by a reaction between the carbon monoxide and oxygen ions conducted through a ceramic membrane, which is an oxygen ion conductor interposed between the cathode and the anode.

[0015] In one embodiment, the byproduct gas may include byproduct gas generated at a steel mill.

[0016] In one embodiment, the amount of hydrogen generated at the cathode can be controlled by adjusting the current flowing through the external circuit.

[0017] In one embodiment, a flat unit cell comprising the cathode, the anode, and the ceramic membrane may be included, and a separator, a current collector, a flat unit cell, and a current collector may be sequentially and repeatedly stacked.

[0018] A production apparatus and a production method according to one embodiment can simultaneously produce hydrogen and electricity.

[0019] A production device and production method according to another specific example can produce hydrogen and electricity from waste gas and water generated at an industrial site.

[0020] In another specific embodiment, the production apparatus and production method can control the production amount of hydrogen simply by adjusting the current.

[0021] The various and beneficial advantages and effects of the present invention are not limited to those described above and will be more easily understood in the process of explaining specific embodiments of the present invention.

[0022] FIG. 1 is a configuration diagram of a production device according to one embodiment.

[0023] FIG. 2 is a diagram showing another configuration of a production device according to one embodiment.

[0024] FIG. 3 is another configuration diagram of a production device according to one embodiment.

[0025] Preferred embodiments of the present invention will be described below with reference to the attached drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

[0026] In addition, embodiments of the present invention are provided to more fully explain the present invention to those with average knowledge in the relevant technical field.

[0027] In drawings, the shapes and sizes of elements may be exaggerated for clearer explanation.

[0028] In describing the embodiments of the present invention, if it is determined that a detailed description of known technology related to the present invention may unnecessarily obscure the essence of the present invention, such detailed description will be omitted. Furthermore, the terms described below are defined considering their functions in the present invention, and these may vary depending on the intentions or conventions of the user or operator. Therefore, such definitions should be based on the content throughout this specification. The terms used in the detailed description are merely for describing the embodiments of the present invention and should not be limited in any way. Unless explicitly stated otherwise, expressions in the singular form include the meaning of the plural form.

[0029] In this description, expressions such as “include” or “equipped” are intended to refer to certain characteristics, numbers, steps, actions, elements, parts or combinations thereof, and should not be interpreted to exclude the existence or possibility of one or more other characteristics, numbers, steps, actions, elements, parts or combinations thereof other than those described.

[0030] Unless otherwise specifically defined in the specification of the present invention, % units mean weight %.

[0031] In this specification, terms such as 'top', 'upper', 'upper surface', 'lower', 'lower surface', 'lower surface', and 'side surface' are based on the drawings and may actually vary depending on the direction in which the elements or components are arranged.

[0032] Additionally, throughout the specification, when it is said that one part is 'connected' to another part, this includes not only cases where they are 'directly connected,' but also cases where they are 'indirectly connected' with other elements in between.

[0033] The present invention will be described in detail below through each embodiment or example of the invention. It should be noted that each embodiment or example described in this specification is not limited to a single embodiment or example, but may also be combined with other embodiments or examples. Accordingly, the citation of claims in the patent claims is merely an example of an embodiment, and the technical concept of the present invention should not be interpreted as being limited only to a combination with the cited claims; rather, combinations with various claims are also included within the scope of the technical concept of the present invention.

[0034] A production device according to the start of work includes a unit cell comprising a cathode, an anode, and a ceramic membrane which is an oxygen ion conductor interposed between the cathode and the anode. A byproduct gas containing carbon monoxide is supplied to the anode of the unit cell, and water is supplied to the cathode. Hydrogen is produced by an electrochemical reaction of water at the cathode of the unit cell, and power is generated through an external circuit that electrically connects the cathode-side current collector and the anode-side current collector of the unit cell.

[0035] As described above, hydrogen can be produced by the electrochemical reaction of water supplied to the cathode, carbon monoxide supplied to the anode electrochemically reacts with oxygen ions conducted through a ceramic membrane, which is an oxygen ion conductor, to produce carbon dioxide and electrons, and the produced electrons flow through an external circuit between the cathode and the anode to produce electricity.

[0036] FIG. 1 is a cross-sectional view illustrating a unit cell (100), a current collector (200, 300), and an external circuit (400) in a production apparatus according to one embodiment. In FIG. 1, the supply gas and the generated gas are illustrated with arrows, and the electrochemical reaction occurring at each electrode is indicated on the corresponding electrode.

[0037] As shown in the example illustrated in FIG. 1, the unit cell (100) may include a cathode (110), an anode (120), and a ceramic membrane (130) interposed between the cathode (110) and the anode (120). A cathode-side current collector (200) may be located on the cathode (110) side of the unit cell (100), and an anode-side current collector (300) may be located on the anode (120) side.

[0038] A supply gas containing water, specifically steam, is supplied to the cathode (110) side to generate hydrogen through an electrochemical reaction.

[0039] A byproduct gas containing carbon monoxide is supplied to the anode (120), and the supplied carbon monoxide can electrochemically react with oxygen ions conducted through a ceramic membrane (130) that selectively conducts oxygen ions (only) to produce carbon dioxide and electrons.

[0040] A cathode (110) that generates hydrogen and an anode (120) that generates electrons are electrically connected by an external circuit (400), so that electrons generated at the anode (120) move to the cathode (110) through the external circuit (400) and can produce power through a load.

[0041] The anode (120) may contain a catalytic material known to promote the oxidation reaction of carbon monoxide and an oxygen ion conductor, and in detail, may contain a composite of the catalytic material and the oxygen ion conductor. In this case, if the catalytic material has oxygen ion conductivity, it is not necessary to contain an oxygen ion conductor. Representative examples of the catalytic material for the carbon monoxide oxidation reaction include metallic nickel, metallic copper, nickel oxide (NiO, etc.), copper oxide (CuO, Cu2O, etc.), ceria (CeO2), LaCrO₃, or mixtures thereof or composites thereof, and representative examples of the oxygen ion conductor may include gadolinium-doped ceria (CGO), samaria-doped ceria (SDC), yttria-stabilized zirconia (YSZ), lanthanum-strontium-gallate-magnesite (LSGM), scandia-stabilized zirconia (SSZ), cerium-doped zirconia, or mixtures thereof. As a practical and representative example, the cathode (110) may include a Ni and / or NiO-yttria-stabilized zirconia composite, a Cu-ceria composite, etc.

[0042] The cathode (110) may contain a catalytic material known to promote an electrochemical reaction that reduces water to hydrogen and an oxygen ion conductor, and in detail, may contain a composite of the catalytic material and the oxygen ion conductor. In this case, if the catalytic material has oxygen ion conductivity, it is not necessary to contain an oxygen ion conductor. Representative examples of catalytic materials for such electrochemical reactions include strontium-doped lanthanum manganese oxide (LSM), strontium-doped lanthanum iron oxide (LSF), strontium-doped lanthanum cobalt oxide (LSC), strontium and cobalt-doped lanthanum iron oxide (LSCF), nickel, nickel oxide, cerium oxide, cobalt oxide, iron oxide, ceria gadolinium oxide (CGO), samaria-doped ceria (SDC), scandia-stabilized zirconia (SSZ), lanthanum strontium gallate magnesite (LSGM), or mixtures thereof or complexes thereof. Representative examples of oxygen ion conductors may include gadolinium-doped ceria (CGO), samaria-doped ceria (SDC), yttria-stabilized zirconia (YSZ), lanthanum-strontium-gallate-magnesite (LSGM), scandia-stabilized zirconia (SSZ), cerium-doped zirconia, or mixtures thereof. A substantial and representative example is that the cathode (110) may be a Ni and / or NiO-yttria-stabilized zirconia composite, or a Cu-ceria composite. A substantial and representative example is that the anode (120) may be a Ni and / or NiO-yttria-stabilized zirconia composite, etc.

[0043] The ceramic membrane (130) may be an oxygen ion conductor that does not conduct electrons but conducts oxygen ions. The material of the ceramic membrane is sufficient to be an oxygen ion conductive material commonly used to conduct oxygen ions in the field of water electrolysis or fuel cells. Practical examples of oxygen ion conductors include gadolinium-doped ceria (CGO), samaria-doped ceria (SDC), yttria-stabilized zirconia (YSZ), lanthanum-strontium-gallate-magnesite (LSGM), scandia-stabilized zirconia (SSZ), cerium-doped zirconia, or mixtures thereof or composites thereof. The ceramic membrane (130) may contain an oxygen ion conductor, and as a more practical example, the ceramic membrane (130) may contain only an oxygen ion conductor as the component involved in conduction.

[0044] The current collector (200, 300) has a porous structure so that the supply gas or byproduct gas can come into smooth contact with the electrode, and it is sufficient to be an electrochemically stable conductive material in an environment of electrochemical reaction of water and / or reduction reaction of carbon monoxide. Specifically, the current collector (200, 300) may have a porous structure such as a porous mesh, grid, or foam, and may be a high heat-resistant metal such as nickel, silver-platinum, cobalt-nickel, cobalt-manganese, copper-manganese, cobalt-nickel-manganese, or cobalt-copper-manganese, or a conductive ceramic.

[0045] The production device receives carbon monoxide-containing byproduct gas through the anode of the unit cell and water (steam) through the cathode, and can discharge carbon dioxide-containing product gas from the anode side and hydrogen-containing product gas from the cathode side. In addition, the anode and cathode are electrically connected through an external circuit that can be connected to an external load, thereby generating electricity.

[0046] As described above, the production device can simultaneously produce hydrogen and electricity, which are clean energy, from carbon monoxide-containing byproduct gas, which is a waste gas. The byproduct gas may be byproduct gas generated at a steel mill, and advantageously, it may be blast furnace gas, converter gas, coke oven gas, or a mixture thereof with a high carbon monoxide content.

[0047] The unit cell may be a planar unit cell comprising a planar anode, a planar ceramic membrane, and a planar cathode. The planar unit cell is more effective at collecting electricity and is advantageous because it has high reaction activity per unit area.

[0048] The production device can generate hydrogen and electricity through a stack structure in which multiple flat unit cells are stacked. This stack structure is advantageous as it enables improved power density, increased output voltage, device miniaturization, and ensures thermal uniformity.

[0049] In detail, as shown in FIG. 2, the production device may include a stack in which a separator (500), a current collector (e.g., an anode-side current collector, 300), a unit cell (100), and a current collector (e.g., a cathode-side current collector, 200) are sequentially and repeatedly stacked. At this time, it goes without saying that a separator (500') may be additionally stacked during the last stacking.

[0050] The separator plate (500) can separate the gas and form a flow path so that the supply gas containing steam and the byproduct gas are not mixed with each other and can flow to the anode and cathode separately, and can be a support body capable of mechanically supporting the stacked structures. FIG. 2 illustrates an example in which a flow path is formed by the lip structure of the separator plate (500), but it goes without saying that the present invention cannot be limited by the specific shape and structure of the flow path provided by the separator plate (500).

[0051] Additionally, the separator (500) can electrically connect two unit cells located above and below the separator (500). When the separator electrically connects (series connection) adjacent unit cells, the separator may correspond to a conventional bipolar plate.

[0052] However, the present invention is not limited to a structure in which unit cells within a stack are electrically connected by a separator (500). For example, the separator may provide a gaseous flow path supplied to each electrode and perform the role of separating the gases from each other, and the current collector in contact with each unit cell may be electrically drawn out so that the unit cells within the stack can be connected in series, parallel, or series / parallel through an external circuit.

[0053] The example of FIG. 2 illustrates an example in which adjacent unit cells are electrically connected by a separator (500). In this case, the external circuit (400) is connected to the anode-side collector (300) at the bottom and the cathode-side collector (200) at the top to form a current path (electrical closed circuit) and can produce power.

[0054] FIG. 3 is another configuration diagram illustrating a stack and an external circuit in a production device according to one embodiment, and may further include a current control unit (410) that controls the amount of current flowing between a cathode-side current collector (200) and an anode-side current collector (300) in the external circuit (400). In the absence of the external circuit (400), the hydrogen production amount is determined by the electrochemical potential difference of oxygen applied to the ceramic membrane (300). In this case, not only is power production impossible, but the hydrogen production amount per unit area is significantly reduced, and since the hydrogen production amount cannot be variably controlled, only a predetermined amount of hydrogen can be produced unless the stack itself is newly manufactured.

[0055] However, according to one embodiment, when electron transfer between the cathode side and the anode side is achieved through an external circuit, not only is power production possible, but the amount of hydrogen produced can also be controlled by a current control unit (410) that controls the amount of current. Specifically, the current control unit (410) can control the amount of current flowing (supplied) to a unit cell or a stack in which unit cells are connected in series, parallel, or series / parallel through a variable resistor member such as a potentiometer or a rheostat. When the demand for hydrogen increases or decreases, the amount of hydrogen produced by the production device can be controlled to meet the demand through the current control unit (410).

[0056] The operating temperature of a unit cell (including unit cells within a stack) may be 600 to 1000°C. During initial operation, the unit cell may be heated to the operating temperature by means of by-product gas generated at the steel mill, heating by an electric heater, and / or heating by a burner. Since the net reaction H2O + CO → H2 + CO2 occurring in the unit cell upon reaching the operating temperature is an exothermic reaction, heating by an external heat source may be stopped during normal operation of the production device. Natural cooling may be achieved by means of cooling by gas injected into the anode and cathode, or by air cooling, thereby maintaining the operating temperature. However, if necessary, a cooling unit may be additionally provided to maintain a constant operating temperature of the stack during normal operation. Cooling may include cooling by water and / or a refrigerant, or cooling by a heat exchanger.

[0057] Water may be supplied to the cathode as steam by heat exchange with the exhaust gas (product gas containing hydrogen or product gas containing carbon dioxide) discharged from the unit cell, but it goes without saying that the present invention is not limited by specific methods or devices for steaming.

[0058] The present invention includes a method for producing hydrogen and electricity using the aforementioned hydrogen and electricity production device.

[0059] A method for producing hydrogen and electricity according to the start of work involves supplying a gas containing steam to a cathode that is electrically connected to an anode by an external circuit to produce hydrogen by the electrolysis of water, and supplying a byproduct gas containing carbon monoxide to the anode to produce carbon dioxide and electrons through a reaction between oxygen ions conducted through a ceramic membrane, which is an oxygen ion conductor, interposed between the cathode and the anode.

[0060] Specifically, the anode-side current collector and the cathode-side current collector can be electrically connected by an external circuit, and electrons generated by the oxidation reaction of carbon monoxide at the anode can move through the external circuit to produce power.

[0061] As described above, the production method according to one embodiment can produce both hydrogen, which is clean energy, and electric power, which is electrical energy, by utilizing byproduct gas, which is waste gas.

[0062] The byproduct gas supplied to the anode may be a carbon monoxide-containing byproduct gas generated at a steel mill, and advantageously may be blast furnace gas, converter gas, coke oven gas, or a mixture thereof with a high carbon monoxide content.

[0063] Water (steam) can be supplied to the cathode, and hydrogen and oxygen ions can be generated at the cathode through the electrochemical reaction of water. Oxygen ions have oxygen ion conductivity and can move to the anode through a ceramic membrane interposed between the anode and the cathode.

[0064] The ceramic membrane may be an oxygen ion conductor that does not conduct electrons but conducts oxygen ions. Practical examples of oxygen ion conductors include gadolinium-doped ceria (CGO), samaria-doped ceria (SDC), yttria-stabilized zirconia (YSZ), lanthanum-strontium-gallate magnesite (LSGM), scandia-stabilized zirconia (SSZ), cerium-doped zirconia, or mixtures or complexes thereof. The ceramic membrane may contain an oxygen ion conductor, and as a more practical example, the ceramic membrane may contain only an oxygen ion conductor as the component involved in conduction.

[0065] In a production method according to one embodiment, hydrogen and electricity can be produced in a stack structure in which a separator, a current collector, a unit cell, and a current collector are sequentially and repeatedly stacked, using a stack of the aforementioned cathode, an anode, and a ceramic membrane which is an oxygen ion conductor interposed between the cathode and the anode as a unit cell. At this time, it is obvious that separator plates may be further stacked so that the separator plates are positioned at both ends of the stack structure. At this time, the unit cell may be a flat unit cell.

[0066] In a stack structure, unit cells located in the stack can be connected in series, parallel, or series / parallel by external connections through separators or current collectors, and a gas containing water (steam) and a byproduct gas can be supplied to the cathode-side flow path and the anode-side flow path provided by the separator, respectively.

[0067] When unit cells are connected in series, the external circuit is connected to two current collectors located at both ends of the serially connected unit cells, providing an electron movement path through the outside of the stack and simultaneously providing power through the moving electrons.

[0068] When unit cells are connected in parallel, the external circuit is connected to the parallel-connected anode-side current collectors and the parallel-connected cathode-side current collectors, providing an electron movement path through the outside of the stack and simultaneously providing power through the moving electrons.

[0069] A production method according to an advantageous example can control the amount of hydrogen produced in a unit cell or stack by adjusting the current flowing through an external circuit. Specifically, the cathode half-reaction for producing hydrogen is H2O + 2e - → H2 + O 2- Accordingly, the reaction can be controlled by the electron supply, and thus, the hydrogen production volume can be controlled by adjusting the amount of current through the external circuit. The control of the current amount in the external circuit can be achieved through a variable resistor located in the current path.

[0070] The operating temperature of a unit cell (including a unit cell within a stack) may be 600 to 1000°C, and the unit cell (or stack) may be heated to the operating temperature by by-product gas (high-temperature waste gas) generated at a steel mill or by a burner and / or heater. During normal operation of the unit cell (or stack), the operating temperature of the unit cell (or stack) can be stably maintained through cooling by gas supplied to the unit cell, cooling by a refrigerant, or cooling by heat exchange. Of course, the water supplied to the unit cell may be heated by heat exchange with the stack or by heat exchange with exhaust gas (hydrogen-containing gas, carbon dioxide-containing gas) produced and discharged from the unit cell, and supplied as steam.

[0071] The present invention is not limited to the examples described above but can be implemented in various different forms, and those skilled in the art will understand that the invention can be implemented in other specific forms without altering the technical concept or essential features of the invention. Therefore, the examples described above should be understood as illustrative in all respects and not restrictive.

[0072] *Explanation of symbols*

[0073] 110 : Cathode

[0074] 120 : Anode

[0075] 130 : Ceramic membrane

[0076] 100 : Unit cell

[0077] 200 : Cathode entire house

[0078] 300 : Anode entire house

[0079] 400 : External circuit

[0080] 410: Current regulator

[0081] 500, 500' : Separator

Claims

1. A unit cell comprising a cathode, an anode, and a ceramic membrane which is an oxygen ion conductor interposed between the cathode and the anode, and A byproduct gas containing carbon monoxide is supplied to the anode, and water is supplied to the cathode. Hydrogen is generated by the electrochemical reaction of water at the cathode of the above unit cell, and A hydrogen and power generation device in which power is generated in an external circuit that electrically connects the cathode-side current collector and the anode-side current collector of the above unit cell.

2. In Paragraph 1, A hydrogen and power generation device comprising a unit cell that is flat, and a production device that includes a stack in which a separator, a current collector, a unit cell, and a current collector are sequentially and repeatedly stacked.

3. In Paragraph 1, A hydrogen and power generation device comprising by-product gas generated in a steel mill.

4. In Paragraph 1, The above external circuit further includes a current control unit that controls the amount of current flowing between the cathode-side current collector and the anode-side current collector, a hydrogen and power generation device.

5. In Paragraph 4, A hydrogen and power generation device in which the amount of hydrogen generated at the cathode is controlled by the current control unit.

6. In Paragraph 4, A hydrogen and power generation device comprising a ceramic membrane comprising gadolinium-doped ceria (CGO), samaria-doped ceria (SDC), yttria-stabilized zirconia (YSZ), lanthanum-strontium-gallate-magnesite (LSGM), scandia-stabilized zirconia (SSZ), cerium-doped zirconia, or a mixture thereof or a composite thereof.

7. A gas containing water is supplied to a cathode electrically connected to an anode by an external circuit to produce hydrogen through the electrochemical reaction of water, and A method for producing hydrogen and electricity, wherein a byproduct gas containing carbon monoxide is supplied to the anode, and carbon dioxide and electrons are produced by a reaction between the carbon monoxide and oxygen ions conducted through a ceramic membrane, which is an oxygen ion conductor interposed between the cathode and the anode.

8. In Paragraph 7, A method for producing hydrogen and electricity, wherein the above-mentioned byproduct gas includes byproduct gas generated in a steel mill.

9. In Paragraph 7, A method for producing hydrogen and electricity, controlling the amount of hydrogen produced at the cathode by adjusting the current flowing through the external circuit.

10. In Paragraph 7, A method for producing hydrogen and electricity, comprising a flat unit cell including the cathode, the anode, and the ceramic membrane, wherein a separator, a current collector, a flat unit cell, and a current collector are sequentially and repeatedly stacked.

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