Electrochemical simultaneous generation of hydrogen and carbon monoxide.

Abstract

Disclosed herein is a method for co-producing carbon monoxide and hydrogen, comprising: (a) providing an electrochemical reactor having an anode, a cathode, and a mixed conducting membrane between the anode and the cathode; (b) introducing a first stream comprising a fuel to the anode; and (c) introducing a second stream comprising carbon dioxide and water to the cathode, wherein carbon monoxide is electrochemically generated from the carbon dioxide and hydrogen is electrochemically generated from the water. In one embodiment, the anode and cathode are separated by a membrane and both are exposed to a reducing environment throughout the entire operation.

Description

[Technical Field]

[0001] The present invention relates generally to the co-production of hydrogen (H2) and carbon monoxide (CO). More specifically, the present invention relates to the electrochemical co-production of hydrogen (H2) and carbon monoxide (CO). [Background technology]

[0002] Carbon monoxide (CO) is a colorless, odorless, tasteless, and flammable gas that is slightly less dense than air. CO is well known for its toxic effects, as it readily combines with hemoglobin to produce carboxyhemoglobin, which is highly toxic above certain concentrations. However, CO is an important component in many chemical and industrial processes. CO has a wide range of functions across all areas of chemistry, including metal-carbonyl catalysis, radical chemistry, and cation and anion chemistry. Carbon monoxide is a strong reducing agent and has been used in pyrometallurgy for centuries to reduce metals from their ores. For example, CO is used to create specialty compounds, such as vitamin A.

[0003] The petroleum and chemical industries require large amounts of hydrogen (H2). For example, large amounts of hydrogen are used in upgrading fossil fuels and producing 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 by water electrolysis, steam reforming, laboratory-scale metal acid processes, thermochemical methods, or anaerobic corrosion. Many countries are aiming to become hydrogen economies.

[0004] In the Fischer-Tropsch process, both CO and H2 are essential building blocks, often produced by converting carbon-rich feedstocks (e.g., coal). The CO and H2 mixture (syngas) can be combined to produce a variety of liquid fuels, for example, via the Fischer-Tropsch process. Syngas can also be converted to lighter hydrocarbons, methanol, ethanol, or plastic monomers (e.g., ethylene). The CO / H2 ratio is critical in all such processes to produce the desired compounds. Conventional technologies require extensive and expensive separation and purification processes to obtain CO and H2 as building blocks.

[0005] Clearly, there is a growing need and interest in developing new technology platforms for producing these building blocks and valuable products. This disclosure discusses the co-production of CO and H via an efficient electrochemical pathway. Furthermore, the methods and systems disclosed herein do not require extensive and expensive separation and purification processes as required by conventional techniques. Summary of the Invention

[0006] Disclosed herein are methods for co-producing carbon monoxide and hydrogen, comprising: (a) providing an electrochemical reactor having an anode, a cathode, and a mixed conducting membrane between the anode and the cathode; (b) introducing a first stream comprising a fuel to the anode; and (c) introducing a second stream comprising carbon dioxide and water to the cathode, wherein carbon monoxide is electrochemically generated from the carbon dioxide and hydrogen is electrochemically generated from the water. In various embodiments, the second stream further comprises hydrogen or carbon monoxide to ensure a truly reducing environment at the cathode throughout operation of the reactor.

[0007] In one embodiment, the anode and cathode are separated by a membrane and both are exposed to a reducing environment throughout the entire operation. In one embodiment, the cathode comprises Ni or NiO and a material selected from the group consisting of YSZ, CGO, SDC, SSZ, LSGM, CoCGO, and combinations thereof. In one embodiment, the anode and cathode and the membrane have the same elements. In one embodiment, the anode and cathode and the membrane comprise Ni-YSZ or LaSrFeCr-SSZ or LaSrFeCr-SCZ or LST-SCZ.

[0008] In one embodiment, the anode comprises Ni or NiO and a material selected from the group consisting of YSZ, CGO, SDC, SSZ, LSGM, CoCGO, and combinations thereof. In one embodiment, the fuel comprises ammonia, syngas, hydrogen, methanol, carbon monoxide, or combinations thereof.

[0009] In one embodiment, the anode is liquid during operation. In one embodiment, the anode comprises tin (Sn), bismuth (Bi), cadmium (Cd), lead (Pb), antimony (Sb), indium (In), silver (Ag), Babbitt metal, or a combination thereof. In one embodiment, the anode comprises lithium carbonate, potassium carbonate, sodium carbonate, or a combination thereof. In one embodiment, the fuel comprises carbon, ammonia, syngas, hydrogen, methanol, carbon monoxide, hydrocarbons, biodiesel, renewable natural gas, biogas, biomass, biowaste, charcoal, petcoke, cooking oil, or a combination thereof.

[0010] In one embodiment, the anode comprises doped or undoped ceria and a material selected from the group consisting of Cu, CuO, Cu2O, Ag, Ag2O, Au, Au2O, Au2O3, Pt, Pd, Ru, Rh, Ir, LaCaCr, LaSrCrFe, YSZ, CGO, SDC, SSZ, LSGM, stainless steel, and combinations thereof. In one embodiment, the fuel comprises a hydrocarbon.

[0011] In one embodiment, the membrane comprises an electronically conductive phase and an ionically conductive phase, wherein the electronically conductive phase comprises doped lanthanum chromite or an electronically conductive metal, or a combination thereof, and the ionically conductive phase comprises 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 (SCZ), and combinations thereof.

[0012] In one embodiment, the film comprises CoCGO or LST (lanthanum doped strontium titanate) stabilized zirconia. In one embodiment, the stabilized zirconia comprises YSZ or SSZ or SCZ (scandiaceria stabilized zirconia). In one embodiment, LST comprises LaSrCaTiO3. In one embodiment, the film comprises nickel, copper, cobalt, or niobium doped zirconia.

[0013] In one embodiment, the cathode exhaust passes through a separator, and the generated carbon monoxide and hydrogen are separated from the exhaust. In one embodiment, the method includes utilizing the separated CO and H to produce methanol, ethanol, hydrocarbons, plastic monomers, polyethylene, or combinations thereof. In one embodiment, the reactor does not include interconnects or current collectors. In one embodiment, the reactor does not generate or receive electricity.

[0014] Further aspects and embodiments are provided in the following drawings, detailed description, and claims. Unless otherwise specified, features described herein may be combined, and all such combinations are within the scope of the present disclosure.

[0015] The following drawings are provided to illustrate certain embodiments described herein. The drawings are merely illustrative and are not intended to limit the scope of the claimed invention, nor are they intended to show every possible feature or embodiment of the claimed invention. The drawings are not necessarily drawn to scale, and in some instances, certain elements of the drawings may be enlarged relative to other elements of the drawings for illustrative purposes. [Brief explanation of the drawings]

[0016] [Figure 1A] 1 illustrates an electrochemical (EC) reactor or electrochemical gas generator according to one embodiment of the present disclosure. [Figure 1B] 1 illustrates an electrochemical (EC) reactor or electrochemical gas generator according to an alternative embodiment of the present disclosure. [Figure 2A] 1 illustrates a tubular electrochemical reactor according to one embodiment of the present disclosure. [Figure 2B] 1 illustrates a cross-sectional view of a tubular electrochemical reactor according to one embodiment of the present disclosure. [Figure 3] 1 illustrates a CO and H2 co-production system with an electrochemical reactor according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] overview The following terms and phrases have the meanings set forth below, unless otherwise specified herein. This disclosure may employ other terms and phrases not expressly defined herein. Such other terms and phrases shall have the meanings that one of ordinary skill in the art would have within the context of this disclosure. In some cases, a term or phrase may be defined in the singular or plural. In such cases, it is understood that the singular term may also include the plural, and vice versa, unless specifically stated to the contrary.

[0018] As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. For example, reference to a "substituent" includes a single substituent as well as two or more substituents, etc. As used herein, "for example," "for instance," "such as," or "including" is meant to introduce an example that further clarifies a more general subject matter. Unless expressly stated otherwise, such examples are provided merely as an aid in understanding the embodiments illustrated in this disclosure and are not intended to be limiting in any way. Furthermore, these terms do not imply any preference of any kind over the disclosed embodiments.

[0019] As used herein, unless otherwise specified, composition and material are used interchangeably. Each composition / material may have multiple elements, phases, and constituents. Heating, as used herein, refers to the active application of energy to a composition or material.

[0020] As used herein, YSZ refers to yttria-stabilized zirconia, SDC refers to samaria-doped ceria, SSZ refers to scandia-stabilized zirconia, and LSGM refers to lanthanum strontium gallate magnesite.

[0021] In this disclosure, the absence of substantial amounts of H2 means that the volumetric hydrogen content 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.

[0022] As used herein, CGO refers to gadolinium-doped ceria, alternatively known as gadolinia-doped ceria, gadolinium-doped cerium oxide, cerium(IV) oxide, gadolinium-doped, GDC, or GCO (formula Gd:CeO). CGO and GDC are used interchangeably unless otherwise specified. Syngas (i.e., synthesis gas) in this disclosure refers to a mixture consisting primarily of hydrogen, carbon monoxide, and carbon dioxide.

[0023] Mixed conducting membranes can transport both electrons and ions. Ionic conductivity includes ionic species such as oxygen ions (or oxide ions), protons, halide anions, chalcogenide anions, etc. In various embodiments, the mixed conducting membranes of the present disclosure include an electronically conducting phase and an ionically conducting phase.

[0024] In this disclosure, the axial cross section of the tubular body is shown as being circular, but this is by way of example only and not limitation, and the axial cross section of the tubular body may be any suitable shape known to those skilled in the art, such as a square, a rounded square, a rectangle, a rounded rectangle, a triangle, a hexagon, a pentagon, an ellipse, an irregular shape, etc.

[0025] As used herein, ceria refers to cerium oxide, also known as cerium oxide, cerium 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 oxide, including all oxidation states of chromium oxide.

[0026] As used herein, an impermeable layer or material refers to one that is impermeable to fluid flow, for example, an impermeable layer or material has a permeability of less than 1 microdarcy or less than 1 nanodarcy.

[0027] In this disclosure, sintering refers to a process of forming a solid mass of material by heat or pressure, or a combination thereof, without melting the material to the point of liquidity. For example, particles of a material are heated to agglomerate into a solid or porous mass, causing atoms within the material particles to diffuse across the particle boundaries and fuse the particles to form one solid piece.

[0028] The term "in situ" in this disclosure refers to a treatment (e.g., heating or cracking) process that occurs either in the same place or in the same device. For example, ammonia cracking that occurs in an electrochemical reactor at the anode is considered in situ.

[0029] Electrochemistry is the branch of physical chemistry concerned with the relationship between electric potential as a measurable and quantitative phenomenon and the electric potential resulting from a specific chemical change, or vice versa. These reactions involve electrons moving between electrodes through an electronically conducting phase (typically, but not necessarily, an external electric circuit) separated by an ionically conducting and electronically insulating membrane (or ionic species in solution). When a chemical reaction is driven by a potential difference, as in electrolysis, or when an electric potential arises from a chemical reaction, as in a battery or fuel cell, it is called an electrochemical reaction. Unlike chemical reactions, in electrochemical reactions, electrons (and the resulting ions) do not move directly between molecules, but rather through the aforementioned electronically and ionically conducting circuits, respectively. This phenomenon distinguishes electrochemical reactions from chemical reactions.

[0030] In connection with electrochemical reactors and methods of use thereof, various components of the reactor, such as electrodes and membranes, are described, along with the components' materials of construction. The following description lists various aspects and embodiments of the invention disclosed herein. The specific embodiments are not intended to define the scope of the invention. Rather, the embodiments provide non-limiting examples of various compositions and methods falling within the scope of the claimed invention. This description should be read from the perspective of one of ordinary skill in the art and, therefore, does not necessarily include information known to one of ordinary skill in the art.

[0031] Interconnects in electrochemical devices (e.g., fuel cells) are often either metal or ceramic that are placed between individual cells or repeating units. Their purpose is to connect each cell or repeating unit so that electricity can be distributed or combined. Interconnects are also referred to as bipolar plates in electrochemical devices. As used herein, an interconnect that is an impermeable layer refers to a layer that is impermeable to fluid flow.

[0032] Electrochemical Reactor Unlike conventional practice, electrochemical reactors have been found that include ion-conducting membranes that can electrochemically reform hydrocarbons or electrochemically perform the water-gas shift reaction. Electrochemical reforming reactions involve the exchange of ions across a membrane to oxidize hydrocarbons. Electrochemical reactions involve the exchange of ions across a membrane and include the forward water-gas shift reaction, the reverse water-gas shift reaction, or both. These differ from traditional reforming and water-gas shift reactions via chemical routes because they involve the direct coupling of reactants.

[0033] 1A illustrates an electrochemical reactor or electrochemical (EC) gas generator 100 according to one embodiment of the present disclosure. The electrochemical reactor (or EC gas generator) device 100 includes a first electrode 101, a membrane 103, and a second electrode 102. The first electrode 101 is configured to receive a fuel 104. For example, the stream 104 may include H, ammonia, syngas, or a combination thereof. The stream 104 does not contain oxygen. The second electrode 102 is configured to receive a stream 105 containing carbon dioxide (CO) and water (HO).

[0034] In one embodiment, the device 100 receives CO and H O; The second electrode (102) is configured to generate CO and H contained in stream 107. In some cases, the second electrode also receives small amounts of CO and / or H. CO and H are considered oxidants in this scenario because they provide the oxide ions (transported through the membrane) necessary to oxidize the fuel at the opposite electrode. The reduction of CO produces CO. The reduction of H produces H. Thus, the first electrode 101 is undergoing an oxidation reaction in a reducing environment, and the second electrode 102 is undergoing a reduction reaction in a reducing environment. In some cases, such environments are considered nominally reducing environments. In various embodiments, both electrodes are exposed to a reducing environment throughout the entire operating time.

[0035] In various embodiments, 103 represents an oxide-ion conducting membrane. In one embodiment, first electrode 101 and second electrode 102 comprise Ni-YSZ or NiO-YSZ. In one embodiment, oxide-ion conducting membrane 103 also conducts electrons. In various embodiments, electrodes 101 and 102 comprise Ni or NiO and a material selected from the group consisting of YSZ, CGO, SDC, SSZ, LSGM, CoCGO, and combinations thereof. Alternatively, the hydrocarbon-containing gas is reformed before contacting membrane 103 / electrode 101. The reformer is configured to perform steam reforming, dry reforming, or a combination thereof. The reformed gas is suitable as feed stream 104.

[0036] In one embodiment, the anode, cathode, and membrane have the same elements. For example, the anode, cathode, and membrane comprise Ni-YSZ. In one embodiment, the anode, cathode, and membrane comprise LaSrFeCr (lanthanum strontium iron doped chromite)-SSZ (scandia stabilized zirconia). In one embodiment, the anode, cathode, and membrane comprise LaSrFeCr-SCZ (Sc and Ce stabilized zirconia). In one embodiment, the anode, cathode, and membrane comprise LST (lanthanum doped strontium titanate)-SCZ.

[0037] In this disclosure, the absence of oxygen means that there is no oxygen at the first electrode 101, or at least not enough oxygen to interfere with the reaction. Also, in this disclosure, water means only that the intended raw material is water, and does not exclude trace elements or inherent components in water. For example, water containing salts or ions is considered to be within the scope of water only. Although water only does not require 100% pure water, this embodiment is included.

[0038] In various embodiments, the device does not include current collectors. In one embodiment, the device does not include interconnects. No electricity is required, and such a device is not an electrolyzer. This is a major advantage of the EC reactor of this disclosure. The membrane 103 is configured to conduct electrons and is itself mixed conducting, i.e., both electronically and ionically conductive. In one embodiment, the membrane 103 conducts oxide ions and electrons. In one embodiment, the electrodes 101, 102, and the membrane 103 are tubular (see Figures 2A and 2B). In one embodiment, the electrodes 101, 102, and the membrane 103 are planar. In these embodiments, the electrochemical reaction at the electrodes occurs spontaneously without the need to apply an electrical potential / electricity to the reactor.

[0039] In one embodiment, an electrochemical reactor (or EC gas generator) is a device comprising a first electrode, a second electrode, and a membrane between the electrodes, wherein the first electrode and the second electrode comprise a metallic phase that does not contain a platinum group metal during use of the device, and the membrane is oxide-ion conductive. In one embodiment, the first electrode is configured to receive a fuel. In one embodiment, the fuel comprises ammonia, syngas, hydrogen, methanol, carbon monoxide, or a combination thereof. In an embodiment, the second electrode is configured to receive CO and HO (with small amounts of CO or H, or both) and is configured to reduce CO to CO and HO to H. In various embodiments, such reduction occurs electrochemically.

[0040] FIG. 1B illustrates an electrochemical reactor or electrochemical (EC) generator 100 for the co-production of hydrogen and carbon monoxide according to one embodiment of the present disclosure. The EC reactor 100 includes a first electrode 101, a membrane 103, and a second electrode 102. In various embodiments, the first electrode 101 is a metal or carbonate configured to carry, suspend, or circulate a feedstock 104 when the reactor is operating, such that the metal or carbonate becomes a liquid. The metal includes tin (Sn), bismuth (Bi), cadmium (Cd), lead (Pb), antimony (Sb), indium (In), silver (Ag), babbitt metal, or a combination thereof. The carbonate includes lithium carbonate, potassium carbonate, sodium carbonate, or a combination thereof.

[0041] The feedstock 104 may include carbon, ammonia, syngas, hydrogen, methanol, carbon monoxide, hydrocarbons, biodiesel, renewable natural gas, biogas, biomass, biowaste, charcoal, petcoke, cooking oil, or combinations thereof. The carbon may be obtained from any source known to those skilled in the art, such as petroleum coke (coke or petcoke), carbon black, charcoal, graphite, coal, biowaste, or biomass. Examples of hydrocarbons are methane, ethane, propane, and butane. In various embodiments, the volume content of solid feedstock (e.g., carbon) in the first electrode is 30% by volume or less. At the first electrode 101, the feedstock 104 is oxidized via oxide ions transported through the membrane 103. For example, carbon is converted to carbon monoxide or carbon dioxide (i.e., carbon oxides). Stream 106 represents the exhaust from the first electrode.

[0042] The second electrode 102 is configured to receive water (e.g., steam) and carbon dioxide, as indicated at 105. In one embodiment, stream 105 also contains hydrogen or carbon monoxide, or both. At the second electrode 102, water is electrochemically reduced to hydrogen, and carbon dioxide is electrochemically reduced to carbon monoxide. Stream 107 represents exhaust from the second electrode. In this scenario, water or carbon dioxide is considered the oxidant because the water provides the oxide ions (transported through the membrane) necessary to oxidize the feedstock at the opposite electrode. Thus, the first electrode 101 is undergoing an oxidation reaction in a reducing environment, and the second electrode 102 is undergoing a reduction reaction in a reducing environment. In one embodiment, the second electrode 102 comprises Ni-YSZ or NiO-YSZ. In various embodiments, the electrode 102 comprises Ni or NiO and a material selected from the group consisting of YSZ, CGO, SDC, SSZ, LSGM, CoCGO, and combinations thereof. In various embodiments, both electrodes are exposed to a reducing environment during the entire run time.

[0043] In various embodiments, 103 represents an oxide-ion conducting membrane. In one embodiment, the oxide-ion conducting membrane 103 also conducts electrons. Thus, the reactor does not include current collectors or interconnects. No electricity is required, and such a reactor is not an electrolyzer. This is a major advantage of the EC reactor of this disclosure. The membrane 103 is configured to conduct electrons and is itself mixed conducting, i.e., both electronically and ionically conducting. In one embodiment, the membrane 103 conducts oxide ions and electrons. In these embodiments, the electrochemical reactions at the anode and cathode occur spontaneously without the need to apply an electrical potential / electricity to the reactor.

[0044] 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-doped ceria (CGO), samarium-doped ceria (SDC), yttria-stabilized zirconia (YSZ), lanthanum strontium gallate magnesite (LSGM), scandia-stabilized zirconia (SSZ), Sc- and Ce-doped zirconia, cobalt-doped gadolinium-doped ceria (CoCGO), and combinations thereof. In one embodiment, the doped lanthanum chromite comprises 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 comprises Ni, Cu, Ag, Au, Pt, Rh, or a combination thereof.

[0045] In one embodiment, the membrane comprises an electronically conductive phase and an ionically conductive phase. In some cases, the electronically conductive phase comprises doped lanthanum chromite, an electronically conductive metal, or a combination thereof, and the ionically conductive phase comprises 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 (SCZ), and combinations thereof. In one embodiment, the membrane comprises CoCGO or LST (lanthanum-doped strontium titanate)-stabilized zirconia. In one embodiment, the stabilized zirconia comprises YSZ, SSZ, or SCZ (scandiaceria-stabilized zirconia). In one embodiment, LST comprises LaSrCaTiO. In one embodiment, the membrane comprises nickel-, copper-, cobalt-, or niobium-doped zirconia.

[0046] In one embodiment, the film comprises cobalt-CGO (CoCGO), i.e., cobalt-doped CGO. 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, LST-SSZ, or LST-SCZ (scandiaceria-stabilized zirconia). In one embodiment, the film consists essentially of LST-YSZ, LST-SSZ, or LST-SCZ. In one embodiment, the film consists of LST-YSZ, LST-SSZ, or LST-SCZ. In this disclosure, LST-YSZ refers to a composite of LST and YSZ. In various embodiments, the LST and YSZ phases are interpenetrated. In this disclosure, LST-SSZ refers to a composite of LST and SSZ. In various embodiments, the LST and SSZ phases are interpenetrated. In this disclosure, LST-SCZ refers to a composite of LST and SCZ. In various embodiments, the LST and SCZ phases interpenetrate. YSZ, SSZ, and SCZ are types of stabilized zirconia.

[0047] FIG. 2A illustrates (not to 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 disposed between the inner tubular structure 202 and the outer tubular structure 204, respectively. The tubular generator 200 further includes a void space 208 for fluid passage. FIG. 2B illustrates (not to 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 disposed between the inner tubular structure 202 and the outer tubular structure 204. The tubular generator 200 further includes a void space 208 for fluid passage.

[0048] In one embodiment, the electrodes and membrane are tubular, with a first electrode being outermost and a second electrode being innermost, the second electrode being configured to receive HO and CO. In one embodiment, the electrodes and membrane are tubular, with a first electrode being innermost and a second electrode being outermost, the second electrode being configured to receive HO and CO. In one embodiment, the electrodes and membrane are planar.

[0049] The electrochemical reactions occurring within the reactor include electrochemical half-cell reactions. In various embodiments, the half-cell reactions occur at three-phase boundaries, which are the intersections of the pores with the electronically and ionically conducting phases.

[0050] In various embodiments, the ion-conducting membrane conducts protons or oxide ions. In various embodiments, the ion-conducting membrane comprises a solid oxide. 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 include interconnects.

[0051] Electrochemical co-generation of H2 and CO The EC reactor described above is suitable for the simultaneous electrochemical production of CO from CO and H from H O on the cathode side. In one embodiment, the reactor comprises porous electrodes including a metal phase and a ceramic phase, where the metal phase is electronically conductive and the ceramic phase is ionically conductive. In various embodiments, the electrodes do not have current collectors attached. In various embodiments, the reactor does not include any current collectors or interconnects. Clearly, such reactors are fundamentally different from electrolysis devices or fuel cells.

[0052] As illustrated in FIG. 3, a system (300) for the co-production of CO and H is shown. System 300 includes an EC reactor 331, a fuel source 311, a carbon dioxide and water source 321, and a separator 341. 301 represents the anode within the reactor, and 302 represents the cathode within the reactor. 303 represents the membrane between the electrodes within the reactor. A first stream 392 containing fuel passes through anode 301, is oxidized, and exits the anode as stream 393. A second stream 394 from source 321 passes through cathode 302, where CO is reduced to CO and H0 is reduced to H. Cathode exhaust stream 395 passes through separator 341, where CO is separated from CO and H0 is separated from H0. Product stream 396 exits separator 341 and consists essentially of CO and H. A portion of stream 395 or stream 396 may be recycled to cathode 302 (not shown in FIG. 3). In various embodiments, the cathode receives hydrogen or carbon monoxide in addition to steam and carbon dioxide to ensure a truly reducing environment throughout the reactor operation. In various embodiments, both electrodes are exposed to a reducing environment during the entire operation.

[0053] The disclosed CO and H co-production process and system have various advantages. CO generation from CO is desirable because it reduces greenhouse gas emissions. Local (on-site) production of CO and H is inherently safer than transporting CO and H in pressurized containers or vessels. The disclosed process utilizes an efficient electrochemical pathway but does not require electricity. CO / CO and H / H0 separation from the cathode exhaust is easy and inexpensive. Thus, the disclosed method and system are cost-competitive in both capital equipment and operating costs.

[0054] In various embodiments, the rate of H / CO co-production is controlled by varying the HO / CO input ratio, by varying the operating temperature, by varying the fuel composition, or a combination thereof. In this manner, the product from the separator is suitable for various downstream chemical production without the need for further purification or modification. This is another major advantage of the disclosed processes and systems.

[0055] Production of valuable products The production system 300 may further include a chemical producer (not shown in FIG. 3 ) selected from the group consisting of a Fischer-Tropsch reactor, a methanol producer, an ethanol producer, a hydrocarbon producer, a plastic monomer producer, and combinations thereof. The Fischer-Tropsch reactor may produce valuable products such as naphtha, gasoline, diesel, wax, etc. The produced methanol may be further converted to gasoline, ethylene, acetic acid, formaldehyde, methyl acetate, polyolefins, dimethyl ether (DME), or combinations thereof. In various embodiments, the chemical producer is configured to receive carbon monoxide and hydrogen from the separator. The system may further include a polymerization unit for converting the plastic monomers into various types of plastics. Configurations and arrangements for utilizing the produced CO and H are known to those skilled in the art, and all such configurations and arrangements are within the scope of the present disclosure.

[0056] It should be understood that this disclosure describes exemplary embodiments for implementing different features, structures, or functions of the present invention. To simplify the disclosure, exemplary embodiments of components, arrangements, and configurations are described; however, these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the present invention. Unless otherwise specified, the embodiments presented herein can be combined, and such combinations do not depart from the scope of the disclosure.

[0057] Additionally, specific terms are used throughout the description and claims to refer to particular components or steps. As one skilled in the art will appreciate, various entities may refer to the same component or process step by different names, and therefore, the naming conventions for elements described herein are not intended to limit the scope of the invention. Furthermore, the terminology and naming conventions used herein are not intended to distinguish between components, functions, and / or steps that differ in name but function.

[0058] While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and description. It should be understood, however, that the drawings and detailed description are not intended to limit the disclosure to the particular forms disclosed, but on the contrary, are intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure.

Claims

1. 1. A method for co-producing carbon monoxide and hydrogen, comprising: (a) providing an electrochemical reactor having an anode, a cathode, and a mixed conducting membrane between the anode and the cathode; (b) introducing a first stream comprising a fuel to the anode; and (c) introducing a second stream comprising carbon dioxide and water to the cathode, wherein carbon monoxide is electrochemically generated from the carbon dioxide and hydrogen is electrochemically generated from the water.

2. 10. The method of claim 1, wherein the anode and the cathode are separated by the membrane and both are exposed to a reducing environment during the entire operation period.

3. 10. The method of claim 1, wherein the cathode comprises Ni or NiO and a material selected from the group consisting of YSZ, CGO, SDC, SSZ, LSGM, CoCGO, and combinations thereof.

4. The method of claim 1 , wherein the anode and cathode and the membrane have the same elements.

5. The method of claim 4, wherein the anode and cathode and the membrane comprise Ni-YSZ or LaSrFeCr-SSZ or LaSrFeCr-SCZ or LST-SCZ.

6. 10. The method of claim 1, wherein the anode comprises Ni or NiO and a material selected from the group consisting of YSZ, CGO, SDC, SSZ, LSGM, CoCGO, and combinations thereof.

7. The method of claim 6 , wherein the fuel comprises ammonia, syngas, hydrogen, methanol, carbon monoxide, or a combination thereof.

8. 10. The method of claim 1, wherein the anode is liquid during operation and comprises tin (Sn), bismuth (Bi), cadmium (Cd), lead (Pb), antimony (Sb), indium (In), silver (Ag), babbitt metal, or a combination thereof, or the anode comprises lithium carbonate, potassium carbonate, sodium carbonate, or a combination thereof.

9. 10. The method of claim 8, wherein the fuel comprises carbon, ammonia, syngas, hydrogen, methanol, carbon monoxide, hydrocarbons, biodiesel, renewable natural gas, biogas, biomass, biowaste, charcoal, petcoke, cooking oil, or combinations thereof.

10. The anode is made of doped or undoped ceria and Cu, CuO, Cu ２ O, Ag, Ag ２ O, Au, Au ２ O, Au ２ O ３ , Pt, Pd, Ru, Rh, Ir, LaCaCr, LaSrCrFe, YSZ, CGO, SDC, SSZ, LSGM, stainless steel, and combinations thereof.

11. The method of claim 10 , wherein the fuel comprises a hydrocarbon.

12. The method of claim 1 , wherein the membrane comprises an electronically conductive phase and an ionically conductive phase.

13. 13. The method of claim 12, wherein the electronically conductive phase comprises doped lanthanum chromite or an electronically conductive metal, or a combination thereof, and the ionically conductive phase comprises 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 (SCZ), and combinations thereof.

14. The method of claim 1 , wherein the film comprises CoCGO or LST (lanthanum doped strontium titanate) stabilized zirconia.

15. The stabilized zirconia includes YSZ, SSZ, or SCZ (scandiaceria stabilized zirconia), and the LST is LaSrCaTiO ３ 15. The method of claim 14, comprising:

16. The method of claim 1 , wherein the film comprises nickel, copper, cobalt, or niobium doped zirconia.

17. 10. The method of claim 1, wherein the cathode exhaust is passed through a separator to separate the generated carbon monoxide and hydrogen from the exhaust.

18. The separated CO and H ２ 20. The method of claim 17, comprising utilizing a catalyst to produce methanol, ethanol, a hydrocarbon, a plastic monomer, polyethylene, or a combination thereof.

19. The method of claim 1 , wherein the reactor does not include an interconnect or a current collector.

20. 10. The method of claim 1, wherein the reactor does not generate or receive electricity.

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