Integrated hydrogen production method and system

Abstract

Discussed herein is a method for producing hydrogen, comprising introducing a metal smelter effluent gas or a basic oxygen furnace (BOF) effluent gas or a mixture thereof into an electrochemical (EC) reactor, the EC reactor comprising a mixed conducting membrane. In one embodiment, the method comprises introducing steam into the EC reactor on one side of the membrane, with the effluent gas on the opposite side of the membrane, and the effluent gas and the steam separated by the membrane and not in contact with each other.

Description

Technical Field

[0001] The present invention generally relates to hydrogen production. More specifically, the present invention relates to an electrochemical hydrogen production method and system.

Background Art

[0002] In the petroleum and chemical industries, large amounts of hydrogen are required. For example, large amounts of hydrogen are used in the improvement of fossil fuels and the production of ammonia or methanol or hydrochloric acid. Petrochemical plants require hydrogen for hydrocracking, hydrodesulfurization, and hydrodealkylation. Hydrogen is also required for hydrogenation processes to increase the saturation level of unsaturated fats and oils. Hydrogen is also a reducing agent for metal ores. Hydrogen can be produced from the electrolysis of water, steam reforming, laboratory-scale metal acid processes, thermochemical methods, or anaerobic corrosion. Many countries aim for a hydrogen economy.

[0003] It is clear that the need and interest in developing new technology platforms for hydrogen production are increasing. The present disclosure discusses hydrogen production using an efficient electrochemical pathway. Electrochemical reactors and methods of performing such reactions are also discussed. In particular, the present disclosure includes a discussion of methods and systems for hydrogen production integrated with a blast furnace or a basic oxygen furnace (BOF).

Summary of the Invention

[0004] A method of producing hydrogen is discussed herein, including introducing a blast furnace off-gas or a basic oxygen furnace (BOF) off-gas or a mixture thereof into an electrochemical (EC) reactor, the EC reactor comprising a mixed conducting membrane. In one embodiment, the method includes introducing steam into the EC reactor on one side of the membrane, the off-gas being on the opposite side of the membrane, the off-gas and the steam being separated by the membrane and not contacting each other.

[0005] In one embodiment, the EC reactor comprises an anode on the exhaust gas side and a cathode on the vapor side, the anode and cathode being separated by a membrane and each in contact with the membrane. In one embodiment, the anode and cathode are separated by a membrane and both are exposed to a reducing environment. In one embodiment, the anode and cathode include Ni or NiO and a material selected from the group consisting of YSZ, CGO, SDC, SSZ, LSGM, and combinations thereof. In one embodiment, at least a portion of the cathode exhaust gas is recirculated and enters the EC reactor on the cathode side.

[0006] In one embodiment, the film comprises an electronically conductive phase containing doped lanthanum chromite or an electronically conductive metal or a combination thereof, and the film comprises an ionically conductive phase containing a material selected from the group consisting of gadolinium or samarium-doped ceria, yttria-stabilized zirconia (YSZ), lanthanum strontium gallate magnesite (LSGM), scandia-stabilized zirconia (SSZ), Sc and Ce-doped zirconia, and combinations thereof. In one embodiment, the doped lanthanum chromite includes strontium-doped lanthanum chromite, iron-doped lanthanum chromite, strontium and iron-doped lanthanum chromite, lanthanum calcium chromite, or a combination thereof, and the conductive metal includes Ni, Cu, Ag, Au, Pt, Rh, Co, Ru, or a combination thereof. In one embodiment, the film comprises CoCGO. In one embodiment, the film comprises LST (lanthanum-doped strontium titanate)-YSZ or LST-SSZ.

[0007] In one embodiment, the reactor does not include interconnects. In one embodiment, the vapor is reduced to hydrogen on the cathode side. In one embodiment, the effluent gas contains CO and CO2, and the CO / CO2 molar ratio is 1 / 5 or more, or 1 / 4 or more, or 1 / 3 or more.

[0008] Furthermore, this specification discusses an integrated hydrogen production system comprising a metal blast furnace or a basic oxygen converter (BOF) and an electrochemical reactor equipped with a mixed conductive membrane that is both ionic and electronically conductive, the reactor capable of electrochemically carrying out a water-gas shift reaction, the electrochemical water-gas shift reaction involving the exchange of ions through the membrane, and including a forward water-gas shift reaction, a reverse water-gas shift reaction, or both.

[0009] In one embodiment, the reactor comprises first and second porous electrodes comprising a metal phase and a ceramic phase, the metal phase being electronically conductive and the ceramic phase being ionically conductive. In one embodiment, the porous electrodes do not have current collectors attached to them. In one embodiment, the porous electrodes are separated by a mixed conductive film and both are exposed to a reducing environment.

[0010] In one embodiment, the reactor is configured to receive effluent gas from a metal blast furnace or a BOF, or both. In one embodiment, the system includes a gas holder between the reactor and the metal blast furnace or BOF, the gas holder being configured to take effluent gas from the metal blast furnace or BOF, or both, and to introduce the effluent gas into the reactor. In one embodiment, the system includes a steam generator, a first porous electrode configured to receive steam from the steam generator, and a second porous electrode configured to receive effluent gas, with the steam and effluent gas being separated by a mixed conductive membrane and not in contact with each other.

[0011] Further aspects and embodiments are provided in the following drawings, detailed description, and claims. Unless otherwise specified, the features described herein are combinatorial, and all such combinations are within the scope of this disclosure.

[0012] The following drawings are provided to illustrate specific embodiments described herein. The drawings are illustrative only and are not intended to limit the scope of the claimed invention, nor are they intended to show all potential features or embodiments of the claimed invention. The drawings are not necessarily drawn to exact scale, and in some examples, certain elements of the drawings may be enlarged relative to other elements of the drawings for illustrative purposes. [Brief explanation of the drawing]

[0013] [Figure 1] An electrochemical (EC) reactor or electrochemical gas generator according to one embodiment of the present disclosure will be illustrated. [Figure 2A] A tubular electrochemical reactor according to one embodiment of this disclosure will be illustrated as an example. [Figure 2B] A cross-sectional view of a tubular electrochemical reactor according to one embodiment of this disclosure is illustrated. [Figure 3] An example of an integrated hydrogen generation system discussed herein, according to an embodiment of this disclosure, is illustrated. [Figure 4A] This example illustrates a simplified process flow diagram (PFD) of a conventional steel manufacturing process. [Figure 4B] This disclosure illustrates a simplified PFD for steelmaking using an integrated hydrogen production system having a conversion electrochemical process for H2 production, which can increase the efficiency of hydrogen used in a blast furnace (BF) and reduce CO2 emissions into the atmosphere, according to one embodiment of this disclosure. [Modes for carrying out the invention]

[0014] overview The disclosure herein describes electrochemical (EC) reactors or EC gas generators capable of carrying out water-gas shift reactions via an electrochemical pathway. EC reactors can also carry out chemical water-gas shift reactions. Such reactors have a variety of applications. For example, EC reactors utilize high-temperature electrochemical processes that are well-suited for producing H2 directly from water using waste gases from BF and BOF. This produced H2 can be used directly in blast furnace processes to reduce the need for coal / petroleum coke and thus substantially reduce net carbon dioxide emissions from the steelmaking process.

[0015] The following description details various aspects and embodiments of the invention disclosed herein. No particular embodiment is intended to define the scope of the invention. Rather, the embodiments provide non-limiting examples of various compositions and methods that fall within the scope of the claimed invention. This description should be read from the perspective of those skilled in the art. Therefore, it does not necessarily contain information that is well known to those skilled in the art.

[0016] Unless otherwise specified herein, the following terms and phrases have the meanings set forth below. This disclosure may use other terms and phrases not expressly defined herein. Such other terms and phrases shall have the meanings that a person skilled in the art would have in the context of this disclosure. In some cases, a term or phrase may be defined in the singular or plural form. In such examples, unless expressly indicated otherwise, any singular term may include its plural counterparts and vice versa.

[0017] Where used herein, the singular forms “a,” “an,” and “the” include multiple references unless the context expressly indicates otherwise. For example, a reference to “substituent” includes a single substituent, as well as two or more substituents, and so on. Where used herein, “for example,” “for instance,” “such as,” or “including” means introducing examples that further clarify a more general subject. Unless expressly indicated otherwise, such examples are provided solely as an aid to understanding the embodiments shown herein and are not intended to limit them in any way. Furthermore, these phrases do not imply any priority of any kind over the disclosed embodiments.

[0018] As used herein, compositions and materials are interchangeable unless otherwise specified. Each composition / material may have multiple elements, phases, and components. As used herein, heating refers to the active application of energy to a composition or material.

[0019] In this disclosure, the absence of substantial amounts of H2 means that the volume content of hydrogen is 5% or less, or 3% or less, or 2% or less, or 1% or less, or 0.5% or less, or 0.1% or less, or 0.05% or less.

[0020] As used herein, CGO refers instead to gadolinium-doped ceria, gadolinium-doped cerium oxide, cerium(IV) oxide, gadolinium-doped GDC, or gadolinium-doped ceria also known as GCO (formula Gd:CeO2). Unless otherwise specified, CGO and GDC are used interchangeably. Syngas (i.e., synthesis gas) in this disclosure refers primarily to a mixture consisting of hydrogen, carbon monoxide, and carbon dioxide.

[0021] As used herein, ceria refers to cerium oxide, also known as ceric oxide, ceric dioxide, or cerium dioxide, which is an oxide of the rare earth metal cerium. Doped ceria refers to ceria doped with other elements such as samaria-doped ceria (SDC), or gadolinium-doped ceria (GDC or CGO). As used herein, chromite refers to chromium oxides including all oxidation states of chromium oxide.

[0022] As used herein, a layer or material that is impermeable refers to the fact that it is impermeable to the flow of a fluid. For example, an impermeable layer or material has a permeability of less than 1 microdarcy, or less than 1 nanodarcy.

[0023] In the present disclosure, sintering refers to a process of forming a solid mass of a material by heat or pressure, or a combination thereof, without melting the material to the extent of liquefaction. For example, material particles are agglomerated into a solid or porous mass by being heated, and atoms within the material particles diffuse across the particle boundaries, and the particles fuse together to form a single solid piece.

[0024] Electrochemical reactor Electrochemistry is a field of physical chemistry that relates to the relationship between potential as a measurable and quantitative phenomenon and distinguishable chemical changes, where the potential is either the result of a particular chemical change or vice versa. These reactions involve electrons moving between electrodes via an electronically conductive phase (typically, but not necessarily, an external electrical circuit) separated by an ion-conductive and electronically insulating membrane (or ionic species in solution). When a chemical reaction is affected by a potential difference, such as in electrolysis, or a potential arises from a chemical reaction, such as in a battery or fuel cell, it is called an electrochemical reaction. Unlike chemical reactions, in electrochemical reactions, electrons (and necessarily the resulting ions) are not transferred directly between molecules but are transferred via the aforementioned electronically conductive circuit and ion-conductive circuit respectively. This phenomenon distinguishes electrochemical reactions from chemical reactions.

[0025] Contrary to conventional implementations, an electrochemical reactor with an ion-conductive membrane has been found, which can electrochemically perform the water-gas shift reaction, and the electrochemical water-gas shift reaction includes the exchange of ions through the membrane and includes the forward water-gas shift reaction, or the reverse water-gas shift reaction, or both. This is different from the water-gas shift reaction via a chemical pathway because the chemical water-gas shift reaction involves direct bonding of reactants.

[0026] In one embodiment, the reactor comprises a porous electrode including a metal phase and a ceramic phase, the metal phase being electronically conductive and the ceramic phase being ionically conductive. In various embodiments, the electrodes do not have current collectors attached to them. In various embodiments, the reactor does not contain any current collectors. Clearly, such a reactor is fundamentally different from any electrolyzer or fuel cell.

[0027] In one embodiment, one of the electrodes in the reactor is an anode configured to be exposed to a reducing environment while electrochemically performing an oxidation reaction. In various embodiments, the electrode includes Ni or NiO and a material selected from the group consisting of YSZ, CGO, SDC, SSZ, LSGM, and combinations thereof.

[0028] The electrochemical water-gas shift reaction that occurs in the reactor includes electrochemical half-cell reactions, which are as follows: [ka]

[0029] In various embodiments, the half-cell reaction takes place at a three-phase boundary, which is the intersection of the electron conduction phase and the ionic conduction phase with the pore. Furthermore, the reactor can also carry out a chemical water-gas shift reaction.

[0030] In various embodiments, the ion-conducting membrane conducts protons or oxide ions. In various embodiments, the ion-conducting membrane contains solid oxides. In various embodiments, the ion-conducting membrane is impermeable to fluid flow. In various embodiments, the ion-conducting membrane also conducts electrons, and the reactor does not contain interconnects.

[0031] In one embodiment, the film comprises an electronically conductive phase containing doped lanthanum chromite or an electronically conductive metal or a combination thereof, and the film comprises an ionically conductive phase containing a material selected from the group consisting of gadolinium or samarium-doped ceria, yttria-stabilized zirconia (YSZ), lanthanum strontium gallate magnesite (LSGM), scandia-stabilized zirconia (SSZ), Sc and Ce-doped zirconia, and combinations thereof. In one embodiment, the doped lanthanum chromite includes strontium-doped lanthanum chromite, iron-doped lanthanum chromite, strontium and iron-doped lanthanum chromite, lanthanum calcium chromite, or a combination thereof, and the conductive metal includes Ni, Cu, Ag, Au, Pt, Rh, or a combination thereof.

[0032] Furthermore, this specification discusses a reactor comprising a bifunctional layer and a mixed conductive film, wherein the bifunctional layer and the mixed conductive film are in contact with each other, and the bifunctional layer catalyzes a reverse water-gas shift (RWGS) reaction and functions as an anode in an electrochemical reaction. In one embodiment, the bifunctional layer as an anode is exposed to a reducing environment, and the electrochemical reaction occurring in the bifunctional layer is oxidation. In one embodiment, the current collector is not attached to the bifunctional layer. In one embodiment, the bifunctional layer comprises Ni or NiO and a material selected from the group consisting of YSZ, CGO, SDC, SSZ, LSGM, and combinations thereof.

[0033] In one embodiment, the film comprises an electronically conductive phase containing doped lanthanum chromite or an electronically conductive metal or a combination thereof, and the film comprises an ionically conductive phase containing a material selected from the group consisting of gadolinium or samarium-doped ceria, yttria-stabilized zirconia (YSZ), lanthanum strontium gallate magnesite (LSGM), scandia-stabilized zirconia (SSZ), Sc and Ce-doped zirconia, and combinations thereof. In one embodiment, the doped lanthanum chromite includes strontium-doped lanthanum chromite, iron-doped lanthanum chromite, strontium and iron-doped lanthanum chromite, lanthanum calcium chromite, or a combination thereof, and the conductive metal includes Ni, Cu, Ag, Au, Pt, Rh, or a combination thereof.

[0034] Such reactors have a variety of applications. In one embodiment, the reactor is used to produce carbon monoxide by hydrogenating carbon dioxide. In another embodiment, the reactor is used to adjust the syngas composition (i.e., the H2 / CO ratio) by converting H2 to CO or CO to H2. In the following discussion, hydrogen production is given as an example, but the applications of the reactor are not limited to hydrogen production.

[0035] Figure 1 shows an electrochemical reactor or electrochemical (EC) gas generator 100 according to one embodiment of the present disclosure. The EC gas generator apparatus 100 comprises a first electrode 101, a membrane 103, and a second electrode 102. The first electrode 101 (also referred to as the anode or bifunctional layer) is configured to receive fuel 104. The flow 104 is oxygen-free. The second electrode 102 is configured to receive water (e.g., steam), as shown by 105.

[0036] In one embodiment, the apparatus 100 is configured to receive CO, i.e., carbon monoxide (104), and generate CO / CO2 (106) at a first electrode (101). The apparatus 100 is also configured to receive water or steam (105) and generate hydrogen (107) at a second electrode (102). In some cases, the second electrode receives a mixture of steam and hydrogen. In this scenario, water is considered the oxidizing agent because it provides the oxide ions (transported through the membrane) necessary to oxidize the CO at the opposite electrode. Thus, the first electrode 101 carries out the oxidation reaction in a reducing environment. In various embodiments, 103 represents an oxide ion conductive membrane. In one embodiment, the first electrode 101 and the second electrode 102 contain Ni-YSZ or NiO-YSZ. In one embodiment, the oxide ion conductive membrane 103 also conducts electrons.

[0037] In one embodiment, the apparatus 100 is configured to simultaneously produce hydrogen 107 from the second electrode 102 and syngas 106 from the first electrode 101. In one embodiment, 104 represents methane and water, or methane and carbon dioxide, entering the apparatus 100. In other embodiments, 103 represents an oxide ion conductive film. In one embodiment, the first electrode 101 and the second electrode 102 may include Ni-YSZ or NiO-YSZ. Arrow 104 represents the inflow of hydrocarbons and water, or hydrocarbons and carbon dioxide. Arrow 105 represents the inflow of water or water and hydrogen. In some embodiments, electrode 101 includes Cu-CGO, or optionally further includes CuO, Cu2O, or a combination thereof. Electrode 102 includes Ni-YSZ or NiO-YSZ. Arrow 104 represents an inflow of hydrocarbons with little to no water, no carbon dioxide, and no oxygen, while 105 represents an inflow of water or water and hydrogen. In this scenario, water is considered the oxidizing agent because it provides the oxide ions (transported through the membrane) necessary to oxidize the hydrocarbons / fuel at the opposite electrode.

[0038] In this disclosure, the absence of oxygen means that oxygen is not present in the first electrode 101, or at least not enough oxygen to prevent the reaction. Also in this disclosure, water means only that the intended raw material is water and does not exclude trace elements or intrinsic components in water. For example, water containing salts or ions is considered to be within the range of water only. Water only does not require 100% pure water, but this embodiment includes such requirements. In the embodiment, the hydrogen produced from the second electrode 102 is pure hydrogen, meaning that hydrogen is the main component in the gas phase produced from the second electrode. In some cases, the hydrogen content is 99.5% or higher. In some cases, the hydrogen content is 99.9% or higher. In some cases, the hydrogen produced from the second electrode is of the same purity as that produced from the electrolysis of water.

[0039] In one embodiment, the first electrode 101 is configured to receive methane and water, or methane and carbon dioxide. In one embodiment, the fuel includes hydrocarbons having a carbon number in the range of 1 to 12, 1 to 10, or 1 to 8. Most preferably, the fuel is methane or natural gas, mainly methane. In one embodiment, the device does not generate electricity and is not a fuel cell.

[0040] In various embodiments, the apparatus does not include a current collector. In one embodiment, the apparatus does not include interconnects. It does not require electricity, and such an apparatus is not an electrolyzer. The membrane 103 is configured to conduct electrons and is therefore mixed conductive, i.e., both electronic and ionic conductive. In one embodiment, the membrane 103 conducts oxide ions and electrons. In one embodiment, electrodes 101, 102 and membrane 103 are tubular (see, for example, Figures 2A and 2B). In one embodiment, electrodes 101, 102 and membrane 103 are planar. In these embodiments, the electrochemical reactions at the anode and cathode occur spontaneously without the need to apply potential / electricity to the reactor.

[0041] In one embodiment, the electrochemical reactor (or EC gas generator) is an apparatus comprising a first electrode, a second electrode, and a membrane between the electrodes, wherein the first and second electrodes contain a metallic phase that does not contain platinum group metals during use of the apparatus, and the membrane is oxide ion conductive. In one embodiment, the first electrode comprises Ni or NiO and a material selected from the group consisting of YSZ, CGO, Samaria-doped ceria (SDC), Scandia-stabilized zirconia (SSZ), LSGM, and combinations thereof. In one embodiment, the first electrode is configured to receive a fuel. In one embodiment, the aforementioned fuel includes hydrocarbons, hydrogen, carbon monoxide, ammonia, or combinations thereof.

[0042] In one embodiment, the second electrode comprises Ni or NiO and a material selected from the group consisting of yttria-stabilized zirconia (YSZ), ceria-gadolinium oxide (CGO), samaria-doped ceria (SDC), scandia-stabilized zirconia (SSZ), lanthanum-strontium gallate-magnesite (LSGM), and combinations thereof. In one embodiment, the second electrode is configured to receive water and hydrogen and to reduce water to hydrogen. In various embodiments, such reduction is carried out electrochemically.

[0043] In one embodiment, the film comprises an electronically conductive phase containing doped lanthanum chromite or an electronically conductive metal or a combination thereof, and the film comprises an ionically conductive phase containing a material selected from the group consisting of gadolinium or samarium-doped ceria, yttria-stabilized zirconia (YSZ), lanthanum strontium gallate magnesite (LSGM), scandia-stabilized zirconia (SSZ), Sc and Ce-doped zirconia, and combinations thereof. In one embodiment, the doped lanthanum chromite includes strontium-doped lanthanum chromite, iron-doped lanthanum chromite, strontium and iron-doped lanthanum chromite, lanthanum calcium chromite, or a combination thereof, and the conductive metal includes Ni, Cu, Ag, Au, Pt, Rh, or a combination thereof.

[0044] Figure 2A shows (not to exact scale) a tubular electrochemical (EC) reactor or EC gas generator 200 according to one embodiment of the present disclosure. The tubular generator 200 includes an inner tubular structure 202, an outer tubular structure 204, and a membrane 206 positioned between the inner tubular structure 202 and the outer tubular structure 204. The tubular generator 200 further includes a void space 208 for a fluid passage. Figure 2B shows (not to exact scale) a cross-sectional view of the tubular generator 200 according to one embodiment of the present disclosure. The tubular generator 200 includes a first inner tubular structure 202, a second outer tubular structure 204, and a membrane 206 between the inner tubular structure 202 and the outer tubular structure 204. The tubular generator 200 further includes a void space 208 for a fluid passage.

[0045] In one embodiment, the electrodes and membrane are tubular, with the first electrode being the outermost and the second electrode being the innermost, and the second electrode being configured to receive water and hydrogen. In one embodiment, the electrodes and membrane are tubular, with the first electrode being the innermost and the second electrode being the outermost, and the second electrode being configured to receive water and hydrogen. In one embodiment, the electrodes and membrane are tubular, and the first and second electrodes contain Ni-YSZ or NiO-YSZ.

[0046] In one embodiment, the reactor includes a catalyst that facilitates a chemical reverse water-gas shift (RWGS) reaction. In one embodiment, the catalyst is a high-temperature RWGS catalyst. In one embodiment, the catalyst is part of the anode in the reactor. In one embodiment, the catalyst is configured to be outside the anode. For example, a Ni-Al2O3 pellet as such a catalyst is placed in a reactor surrounding a tube, as shown in Figures 2A and 2B. In one embodiment, the catalyst includes Ni, Cu, Fe, Pt group metals, or combinations thereof. In one embodiment, the catalyst includes Pt, Cu, Rh, Ru, Fe, Ni, or combinations thereof.

[0047] Hydrogen generation system and method A method disclosed herein provides an apparatus comprising a first electrode, a second electrode, and a membrane between the electrodes, and includes introducing a first flow to the first electrode, introducing a second flow to the second electrode, and extracting hydrogen from the second electrode, wherein the first and second electrodes contain a metallic phase that does not contain platinum group metals during use of the apparatus. In one embodiment, the membrane is oxide ion conductive.

[0048] In one embodiment, the device operates at a temperature of 500°C or higher, or 600°C or higher, or 700°C or higher, or 750°C or higher, or 800°C or higher, or 850°C or higher, or 900°C or higher, or 950°C or higher, or 1000°C or higher. In various embodiments, the pressure difference between the first electrode and the second electrode is 2 psi or less, or 1.5 psi or less, or 1 psi or less. In one embodiment, the first flow enters the device at a pressure of 10 psi or less, or 5 psi or less, or 3 psi or less. In one embodiment, the second flow enters the device at a pressure of 10 psi or less, or 5 psi or less, or 3 psi or less.

[0049] In one embodiment, the first flow includes a fuel. In one embodiment, the aforementioned fuel includes a hydrocarbon, hydrogen, carbon monoxide, ammonia, or a combination thereof. In one embodiment, the first flow is introduced directly to the first electrode, or the second flow is introduced directly to the second electrode, or both. In one embodiment, the method includes providing a reformer or catalytic partial oxidation (CPOX) reactor upstream of the first electrode, wherein the first flow passes through the reformer or CPOX reactor before being introduced to the first electrode, and the first electrode contains Ni or NiO. In one embodiment, the reformer is a steam reformer or a self-heating reformer.

[0050] In one embodiment, the first flow contains fuel. In one embodiment, the fuel contains hydrocarbons, hydrogen, carbon monoxide, ammonia, or a combination thereof. In one embodiment, the second flow consists of water and hydrogen. In one embodiment, the aforementioned first flow contains carbon monoxide and does not contain significant amounts of hydrogen, hydrocarbons, or water. In such cases, an upstream reformer is not required. In this disclosure, the absence of significant amounts of hydrogen, hydrocarbons, or water means that the volume content of hydrogen, hydrocarbons, or water is 5% or less, or 3% or less, or 2% or less, or 1% or less, or 0.5% or less, or 0.1% or less, or 0.05% or less.

[0051] In various embodiments, the first flow contains 50% or more by volume of CO, or 60% or more by volume of CO, or 70% or more by volume of CO, or 80% or more by volume of CO, or 90% or more by volume of CO. In one embodiment, the first flow contains CO2. In one embodiment, the first flow contains syngas (CO and H2). In one embodiment, the first flow contains an inert gas such as argon or nitrogen. In one embodiment, the second flow consists of water and hydrogen.

[0052] In one embodiment, the method involves using the extracted hydrogen in one of the following: a Fischer-Tropsch (FT) reaction, a dry reforming reaction, a nickel-catalyzed Sabatier reaction, a Bosch reaction, a reverse water-gas shift reaction, an electrochemical reaction for generating electricity, ammonia production, fertilizer production, an electrochemical compressor for hydrogen storage, an energy supply hydrogen vehicle or hydrogenation reaction, or a combination thereof.

[0053] This specification discloses a method for producing hydrogen, comprising providing an electrochemical reactor, introducing a first flow containing fuel into the apparatus, introducing a second flow containing water into the apparatus, reducing the water in the second flow to hydrogen, and extracting hydrogen from the apparatus, wherein the first and second flows do not come into contact with each other within the apparatus. In various embodiments, the reduction from water to hydrogen is carried out electrochemically. In one embodiment, the first flow does not come into contact with hydrogen. In one embodiment, the first and second flows are separated by a membrane within the apparatus.

[0054] In one embodiment, the fuel includes hydrocarbons, hydrogen, carbon monoxide, ammonia, or a combination thereof. In one embodiment, the second flow includes hydrogen. In one embodiment, the first flow includes fuel. In one embodiment, the fuel consists of carbon monoxide. In one embodiment, the first flow consists of carbon monoxide and carbon dioxide. In one embodiment, the second flow consists of water and hydrogen. In one embodiment, the second flow consists of steam and hydrogen.

[0055] An integrated hydrogen production system 300 is shown, illustrated in Figure 3. The system comprises a metal blast furnace or BOF 310, a steam generator 330, and an electrochemical (EC) reactor or gas generator 320. In various embodiments, the metal blast furnace is used to produce iron or steel. BOF (Basic Oxygen Converter) is known as the basic oxygen steelmaking process, and this process is often called BOS, BOP, or OSM. This process is also known as Linz-Donawitz steelmaking or the oxygen converter process, in which carbon-rich molten pig iron is made into steel. The gas generator / EC reactor 320 generates a first product flow 324 (at the anode) containing CO and CO2, and a second product flow 322 (at the cathode) containing H2 and H2O, the two product flows not in contact with each other. The exhaust flow 323 from the metal blast furnace or BOF enters the gas generator / EC reactor 320 and is used as fuel at the reactor anode (e.g., CO contained in flow 323). The anode exhaust flow 324 has a higher CO2 content compared to flow 323 and potentially contains a certain amount of unreacted CO. The steam generator 330 provides steam 321 to the EC reactor or gas generator 320. Flow 323 and steam 321 do not come into contact with each other within the EC reactor and are separated by a membrane inside the reactor.

[0056] In some cases, the system 300 includes a carbon capture unit 340, and at least a portion of the first productive flow 324 is sent to the carbon capture unit 340 to sequestrate CO2. In one embodiment, a portion of the first productive flow is used to generate steam from water, which is optionally combined with carbon capture upstream of the carbon capture unit, for example. In some cases, a portion of the second productive flow 322 is recirculated and enters an EC reactor (cathode side). In one embodiment, the steam in the second productive flow 322 is condensed and separated as water (e.g., flow 326) and hydrogen is extracted. In some cases, at least a portion of the extracted hydrogen is used in a metal blast furnace or BOF 310, as represented by flow 325 in Figure 3. In various embodiments, the EC reactor 320 includes an ion-conducting membrane (not shown in Figure 3), which, together with the anode, enables the reactor to perform an electrochemical water-gas shift reaction, which involves the exchange of ions through the membrane and includes a forward water-gas shift reaction, a reverse water-gas shift reaction, or both. The reactor can also perform a chemical water-gas shift reaction using the anode.

[0057] In various embodiments, the EC reactor oxidizes the effluent in a reducing environment to produce a first productive flow containing CO and CO2, and the EC reactor electrochemically reduces the vapor to hydrogen to generate a second productive flow containing H2 and H2O. In various embodiments, a membrane separates the first and second productive flows. In various embodiments, at least a portion of the first productive flow is used to produce vapor from water. In various embodiments, at least a portion of the first productive flow is sent to a carbon capture unit to sequester CO2. In various embodiments, at least a portion of the second productive flow is recycled and enters the EC reactor. In one embodiment, water is condensed and separated from the second productive flow to extract hydrogen. The extracted hydrogen is used in various applications as previously discussed herein. In addition, the extracted hydrogen is used to reduce metal ores. For example, hydrogen is used in blast furnaces or direct reduction processes.

[0058] A steam generator produces steam from water. In one embodiment, the steam entering the electrochemical reactor has a temperature of 600°C or higher, or 700°C or higher, or 800°C or higher, or 850°C or higher, or 900°C or higher, or 950°C or higher, or 1000°C or higher, or 1100°C or higher. In one embodiment, the steam entering the electrochemical reactor has a pressure of 10 psi or less, or 5 psi or less, or 3 psi or less.

[0059] Therefore, hydrogen is produced by introducing vapor and / or effluent from a metal blast furnace or BOF into an electrochemical (EC) reactor, wherein the effluent and / or vapor do not come into contact with each other within the EC reactor. The EC reactor is equipped with an ion-conducting membrane, and the reactor can carry out a water-gas shift reaction electrochemically, which involves ion exchange through the membrane and includes a forward water-gas shift reaction, a reverse water-gas shift reaction, or both. Furthermore, the membrane separates the effluent flow from the vapor. In various embodiments, the pressure difference between the product flow side and the vapor side is 2 psi or less, or 1.5 psi or less, or 1 psi or less.

[0060] In one embodiment, at least a portion of the anode exhaust gas is used to generate steam from water. In one embodiment, at least a portion of the anode exhaust gas is sent to a carbon capture unit. In one embodiment, at least a portion of the cathode exhaust gas is recirculated and enters the EC reactor on the cathode side. In one embodiment, at least a portion of the cathode exhaust gas is dehydrated to separate water from hydrogen.

[0061] In one embodiment, the film comprises an electronically conductive phase containing doped lanthanum chromite or an electronically conductive metal or a combination thereof, and the film comprises an ionically conductive phase containing a material selected from the group consisting of gadolinium or samarium-doped ceria, yttria-stabilized zirconia (YSZ), lanthanum strontium gallate magnesite (LSGM), scandia-stabilized zirconia (SSZ), Sc and Ce-doped zirconia, and combinations thereof. In one embodiment, the doped lanthanum chromite includes strontium-doped lanthanum chromite, iron-doped lanthanum chromite, strontium and iron-doped lanthanum chromite, lanthanum calcium chromite, or a combination thereof, and the conductive metal includes Ni, Cu, Ag, Au, Pt, Rh, Co, Ru, or a combination thereof.

[0062] In one embodiment, the film comprises cobalt CGO (CoCGO). In one embodiment, the film consists essentially of CoCGO. In one embodiment, the film consists of CoCGO. In one embodiment, the film comprises LST (lanthanum-doped strontium titanate)-YSZ or LST-SSZ. In this disclosure, LST-YSZ refers to a composite of LST and YSZ. In various embodiments, the LST phase and YSZ phase permeate each other. In this disclosure, LST-SSZ refers to a composite of LST and SSZ. In various embodiments, the LST phase and SSZ phase permeate each other. In one embodiment, the film consists essentially of LST-YSZ or LST-SSZ. In one embodiment, the film consists of LST-YSZ or LST-SSZ.

[0063] In one embodiment, the reactor does not include interconnects. In one embodiment, the effluent gas contains CO and CO2, and the CO / CO2 molar ratio is 1 / 5 or more, or 1 / 4 or more, or 1 / 3 or more. In one embodiment, the effluent gas has a temperature of 700°C or more, or 800°C or more, or 900°C or more.

[0064] In one embodiment, the steam is reduced to hydrogen on the cathode side. In one embodiment, the method includes using hydrogen to reduce a metal ore. In one embodiment, the method includes dehydrating the cathode flue gas before using hydrogen to reduce the metal ore. In one embodiment, the hydrogen is used in a blast furnace or direct reduction process.

[0065] Furthermore, this specification discusses an integrated hydrogen production system comprising a metal blast furnace or a basic oxygen converter (BOF) and an electrochemical reactor equipped with a mixed conductive membrane, the reactor capable of electrochemically carrying out a water-gas shift reaction, the electrochemical water-gas shift reaction involving the exchange of ions through the membrane, and including a forward water-gas shift reaction, a reverse water-gas shift reaction, or both.

[0066] In various embodiments, the reactor is configured to receive effluent gases from a metal blast furnace, a BOF, or both. In some embodiments, a gas holder (not shown in Figure 3) is located between the reactor and the metal blast furnace or BOF. The gas holder contains effluent gases from the metal blast furnace or BOF, or both, and is configured to deliver the effluent gases to the reactor. In various embodiments, the gas holder can maintain the gases within a desired temperature range (e.g., above 700°C).

[0067] In one embodiment, the reactor comprises porous electrodes containing a metallic phase and a ceramic phase, where the metallic phase is electronically conductive and the ceramic phase is ionically conductive. In one embodiment, the electrodes do not have current collectors attached to them. In one embodiment, the electrodes are separated by a film and both are exposed to a reducing environment. In one embodiment, the electrodes include Ni or NiO and a material selected from the group consisting of YSZ, CGO, SDC, SSZ, LSGM, and combinations thereof.

[0068] In one embodiment, the electrochemical water-gas shift reaction includes an electrochemical half-cell reaction, which is as follows: [ka]

[0069] In one embodiment, the half-cell reaction takes place at the three-phase boundary, which is the intersection of the electron conduction phase and the ionic conduction phase with the pore.

[0070] In one embodiment, the reactor can also carry out a chemical water-gas shift reaction. In one embodiment, the ion-conducting membrane conducts protons or oxide ions. In one embodiment, the ion-conducting membrane contains a metal oxide. In one embodiment, the ion-conducting membrane is impermeable to fluid flow.

[0071] In one embodiment, the film comprises an electronically conductive phase containing doped lanthanum chromite or an electronically conductive metal or a combination thereof, and the film comprises an ionically conductive phase containing a material selected from the group consisting of gadolinium or samarium-doped ceria, yttria-stabilized zirconia (YSZ), lanthanum strontium gallate magnesite (LSGM), scandia-stabilized zirconia (SSZ), Sc and Ce-doped zirconia, and combinations thereof. In one embodiment, the doped lanthanum chromite includes strontium-doped lanthanum chromite, iron-doped lanthanum chromite, strontium and iron-doped lanthanum chromite, lanthanum calcium chromite, or a combination thereof, and the conductive metal includes Ni, Cu, Ag, Au, Pt, Rh, Co, Ru, or a combination thereof.

[0072] In one embodiment, the ion-conducting membrane also conducts electrons, and the reactor does not contain interconnects. In one embodiment, the membrane contains cobalt CGO (CoCGO). In one embodiment, the membrane consists essentially of CoCGO. In one embodiment, the membrane consists of CoCGO. In one embodiment, the membrane contains LST (lanthanum-doped strontium titanate)-YSZ or LST-SSZ. In one embodiment, the membrane consists essentially of LST-YSZ or LST-SSZ. In one embodiment, the membrane consists of LST-YSZ or LST-SSZ. [Examples]

[0073] Figure 4A illustrates a typical steelmaking process. Iron ore (401) and coke (402) are sent to a blast furnace (BF, 410) to produce pig iron (404), which is then sent to a basic oxygen converter (BOF, 420) with an oxygen inflow (405) to convert the pig iron into steel. CO and CO2 are produced from both the BF and BOF. CO and CO2 (403, 406, 407) are sent to a steam boiler (430) to generate steam (432) from water using air (431) as an oxidizer. CO2 and N2 are discharged from the steam boiler as exhaust gas (433). In contrast, Figure 4B illustrates a simplified PFD for steelmaking using an integrated hydrogen production system, where the steam boiler 430 in Figure 4A is replaced by the EC reactor / gas generator 440 in Figure 4B. According to one embodiment of the present disclosure, the reactor / generator has a conversion electrochemical process for H2 production in which hydrogen (442) is used in a blast furnace (BF, 410) to increase efficiency and reduce CO2 emissions into the atmosphere. As shown in Figure 4B, CO / CO2 streams (403, 406, 407) from the BF and BOF are sent to the EC reactor / gas generator (440) as fuel on the anode side. Steam (441) is sent to the EC reactor / gas generator 440 on the cathode side. The anode product gas (or anode exhaust, 443) is ready for carbon capture to sequestrate CO2. The cathode product gas (or cathode exhaust, 442) is dehydrated, and the generated hydrogen is sent to the BF to reduce iron ore. The hydrogen used in the BF reduces the amount of coke required, resulting in a reduction of more than 11 tons of CO2 emissions per ton of H2.

[0074] High-CO (e.g., 50%–90% CO content) off-gases from BF and / or BOF are suitable for use with the EC reactor of this disclosure. The EC reactor requires little to no auxiliary electricity or fuel. In particular, this integrated process / system converts CO in BF and BOF gases into high-purity CO2 without the addition of N2, resulting in an exhaust flow of CO2 purity sufficient to enable economic CO2 sequestration. For example, 17 of the top 18 steel plants in the United States with BOF are located directly above or near saline aquifers suitable for CO2 sequestration. The potential emission reductions from CO2 sequestration are estimated to be in the range of 30–90 tons of CO2 per ton of H21 produced for BOF and BF, respectively. Implementing this technology in the top 15 CO2-emitting steel plants in the United States would reduce and / or sequestrate more than 20 million tons of CO2 annually. By using waste streams from BOF and BF, the amount of energy required to manufacture steel is reduced, thereby improving the overall energy efficiency of the manufacturing process.

[0075] It should be understood that this disclosure describes exemplary embodiments for implementing different features, structures, or functions of the present invention. Exemplary embodiments of components, arrangements, and configurations are described for the sake of brevity of this disclosure, but these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the invention. The embodiments presented herein may be combined unless otherwise specified. Such combinations do not depart from the scope of this disclosure.

[0076] Furthermore, certain terms are used throughout the description and claims to refer to specific components or steps. As those skilled in the art will understand, various entities may refer to the same component or process step by different names, and therefore the naming conventions of the elements described herein are not intended to limit the scope of the invention. Furthermore, the terms and naming conventions used herein are not intended to distinguish components, features, and / or steps that have different names but do not differ in function.

[0077] This disclosure is susceptible to various modifications and alternative forms, although specific embodiments are shown as examples in the drawings and description. However, it should be understood that the drawings and detailed description are not intended to limit this disclosure to any particular form, but rather to encompass all modifications, equivalents, and alternatives that fall within the spirit and scope of this disclosure.

Claims

1. A method for producing hydrogen, comprising introducing effluent gas from a metal blast furnace or a basic oxygen converter (BOF), or a mixture thereof, into an electrochemical (EC) reactor, The aforementioned EC reactor, In response to the aforementioned leaked gas containing CO, ２ A first electrode configured to generate, A second electrode configured to receive water or water vapor and generate hydrogen, A mixed conductive film having both electronic and ionic conductivity is located between the first electrode and the second electrode, Equipped with, The aforementioned mixed conductive film includes, as a material having both electronic and ionic conductivity, CoCGO (cobalt-doped CGO, where CGO is gadolinium-doped ceria), LST (lanthanum-doped strontium titanate)-YSZ (yttria-stabilized zirconia), or LST-SSZ (scandia-stabilized zirconia). The mixed conductive film contains oxide ions (O) between the first electrode and the second electrode. ２－ ) and electrons are configured to be transported through the mixed conductive film, A method wherein the EC reactor is configured to operate without the supply of electricity or potential from an external source.

2. The method according to claim 1, comprising introducing steam into the EC reactor on the second electrode side of the mixed conductive membrane, wherein the steam and the outflow gas on the first electrode side of the mixed conductive membrane are separated by the mixed conductive membrane and do not come into contact with each other.

3. The method according to claim 1, wherein the first electrode and the second electrode are separated by the mixed conductive film and each is in contact with the mixed conductive film.

4. The method according to claim 1, wherein the first electrode and the second electrode are separated by the mixed conductive film and both are exposed to a reducing environment.

5. The method according to claim 1, wherein the first electrode and the second electrode each include Ni or NiO and a material selected from the group consisting of yttria-stabilized zirconia (YSZ), gadolinium-doped ceria (CGO), samaria-doped ceria (SDC), scandia-stabilized zirconia (SSZ), lanthanum strontium gallate magnesite (LSGM), and combinations thereof.

6. The method according to claim 1, wherein at least a portion of the exhaust gas on the second electrode side discharged from the EC reactor is recirculated and enters the EC reactor on the second electrode side of the mixed conductive membrane.

7. The method according to claim 1, wherein the water vapor is reduced to hydrogen on the second electrode side.

8. The aforementioned leaked gas is CO and CO ２ Including CO / CO ２ The method according to claim 1, wherein the molar ratio is 1 / 5 or more, or 1 / 4 or more, or 1 / 3 or more.

9. A metal blast furnace or a basic oxygen converter (BOF), An integrated hydrogen production system comprising an electrochemical (EC) reactor capable of performing a water-gas shift reaction in the forward, reverse, or both directions, The EC reactor is configured to receive effluent gas from the metal blast furnace, the BOF, or both. The aforementioned EC reactor is In response to the aforementioned leaked gas containing CO, ２ A first electrode configured to generate, A second electrode configured to receive water or water vapor and generate hydrogen, A mixed conductive film having both electronic and ionic conductivity is located between the first electrode and the second electrode, Equipped with, The aforementioned mixed conductive film includes, as a material having both electronic and ionic conductivity, CoCGO (cobalt-doped CGO, where CGO is gadolinium-doped ceria), LST (lanthanum-doped strontium titanate)-YSZ (yttria-stabilized zirconia), or LST-SSZ (scandia-stabilized zirconia). The mixed conductive film contains oxide ions (O) between the first electrode and the second electrode. ２－ ) and electrons are configured to be transported through the mixed conductive film, An integrated hydrogen production system in which the EC reactor is configured to operate without the need for an external supply of electricity or potential.

10. The system according to claim 9, wherein each of the first electrode and the second electrode of the EC reactor is a porous electrode comprising a metal phase and a ceramic phase, the metal phase being electronically conductive and the ceramic phase being ionically conductive.

11. The system according to claim 9, wherein no current collectors are attached to the first electrode and the second electrode.

12. The system according to claim 9, wherein the first electrode and the second electrode are separated by the mixed conductive film and both are exposed to a reducing environment.

13. The system according to claim 9, wherein a gas holder is provided between the EC reactor and the metal blast furnace or the BOF, and the gas holder is configured to receive the effluent gas and introduce the effluent gas into the EC reactor.

14. The system according to claim 9, comprising a steam generator, wherein the second electrode is configured to receive steam from the steam generator, and the steam and the outflow gas received by the first electrode are separated by the mixed conductive membrane and do not come into contact with each other.

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