Electrochemical generation of carbon monoxide and valuable products

Abstract

Contemplated herein is a method of producing carbon monoxide 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 to the anode, the first stream comprising a fuel; and (c) introducing a second stream to the cathode, the second stream comprising carbon dioxide, where the carbon monoxide is electrochemically generated from the carbon dioxide; wherein the reactor does not generate or accept electricity. In one embodiment, the anode and cathode are separated by a membrane and both are exposed to a reducing environment during the entire time of operation.

Description

[Technical field]

[0001] The present invention relates generally to the production of carbon monoxide (CO) and related valuable products. More specifically, the present invention relates to the electrochemical production of carbon monoxide (CO) and related valuable products. [Background technology]

[0002] Carbon monoxide (CO) is a colorless, odorless, tasteless, and flammable gas that is slightly less dense than air. It is well known for its toxic effects, as it easily 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, for example, 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. As an example for making specialty compounds, CO is used in the production of 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 in the production of methanol or hydrochloric acid. Petrochemical plants require hydrogen for hydrocracking, hydrodesulfurization, and hydrodealkylation. Hydrogenation processes to increase the saturation levels of unsaturated fats and oils also require hydrogen. Hydrogen is also a reducing agent for metal ores. Hydrogen can be produced from electrolysis of water, steam reforming, laboratory-scale metal acid processes, thermochemical methods, or anaerobic corrosion. Many countries are aiming for a hydrogen economy.

[0004] In the Fischer-Tropsch process, both CO and H2 are essential building blocks and are often produced by converting carbon-rich feedstocks (e.g., coal). A mixture of CO and H2 syngas can be combined to produce various 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 ratio of CO / H2 is important 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 an increasing need and interest to develop new technology platforms for producing these building blocks and valuable products. The present disclosure contemplates the production of valuable products via an efficient electrochemical route. Furthermore, the methods and systems disclosed herein do not require extensive and expensive separation and purification processes as required in the prior art. Summary of the Invention

[0006] Contemplated herein is a method of producing carbon monoxide 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 to the anode, the first stream comprising a fuel; and (c) introducing a second stream to the cathode, the second stream comprising carbon dioxide, and the carbon monoxide being electrochemically generated from the carbon dioxide; wherein the reactor neither generates nor accepts electricity.

[0007] In one embodiment, the fuel comprises ammonia, syngas, hydrogen, methanol, carbon monoxide, or a combination thereof. In one embodiment, the cathode exhaust passes through a separator and the generated carbon monoxide is separated from the carbon dioxide. In one embodiment, the second stream comprises carbon monoxide, which is less than carbon dioxide. In some embodiments, the anode and cathode are separated by a membrane and both are exposed to a reducing environment during operation of the reactor. In some of these embodiments, both the anode and cathode are exposed to a reducing environment during the entire operation of the reactor. In others of these embodiments, both the anode and cathode are exposed to a reducing environment while carbon monoxide is produced from carbon dioxide at the cathode.

[0008] In one embodiment, the anode and cathode have the same elements. In one embodiment, the anode and cathode and the membrane have the same elements. In one embodiment, the anode and cathode and the membrane include Ni-YSZ or LaSrFeCr-SSZ or LaSrFeCr-SCZ. 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, CoCGO, and combinations thereof.

[0009] In one embodiment, the membrane comprises an electronically conductive phase and an ionically conductive phase. In one embodiment, the electronically conductive phase comprises doped lanthanum chromite or an electronically conductive metal, or a combination thereof. In one embodiment, 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.

[0010] 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 (scan diaceria stabilized zirconia), and LST comprises LaSrCaTiO3. In one embodiment, the film comprises nickel, copper, cobalt, or niobium doped zirconia.

[0011] Also contemplated herein is a method of producing valuable products comprising: (a) providing two electrochemical reactors, each having an anode, a cathode, and a mixed conducting membrane between the anode and the cathode; (b) introducing a fuel stream to each of the anodes; and (c) introducing a CO2-containing stream to the first cathode and an HO-containing stream to the second cathode, wherein carbon monoxide is electrochemically generated from carbon dioxide and hydrogen is electrochemically generated from water, and wherein the reactors do not generate or accept electricity.

[0012] In one embodiment, CO is separated from CO from a first cathode exhaust stream and H is separated from HO from a second cathode exhaust stream. In one embodiment, the method includes utilizing the separated CO and separated H to produce methanol, ethanol, hydrocarbons, plastic monomers, polyethylene, or combinations thereof.

[0013] In one embodiment, the anode and cathode are each separated by a membrane and all are exposed to a reducing environment during the entire time of operation.

[0014] 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 (scan diaceria stabilized zirconia), and LST comprises LaSrCaTiO3. In one embodiment, the film comprises nickel, copper, cobalt, or niobium doped zirconia.

[0015] Further aspects and embodiments are provided in the following drawings, detailed description, and claims. Unless otherwise specified, features described herein can be combined, and all such combinations are within the scope of the disclosure.

[0016] The following drawings are provided to illustrate certain embodiments described herein. The drawings are merely exemplary 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 description of the drawings]

[0017] [Figure 1] 1 illustrates an electrochemical (EC) reactor or electrochemical gas generator according to one 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 3A] 1 illustrates a CO production system having an electrochemical reactor, according to one embodiment of the present disclosure. [Figure 3B] 1 illustrates a chemical production system having two electrochemical reactors, according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] overview Unless otherwise defined 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 they would have within the context of this disclosure to one of ordinary skill in the art. In some cases, a term or phrase may be defined in the singular or plural. In such instances, it is understood that any term in the singular may include its plural counterpart, and vice versa, unless expressly indicated to the contrary.

[0019] 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, and so forth. As used herein, "for example," "for instance," "such as," or "including" are meant to introduce examples that further clarify a more general subject matter. Unless expressly indicated otherwise, these examples are provided only as an aid to understanding the embodiments illustrated in this disclosure and are not intended to be limiting in any way. Additionally, these phrases do not indicate any kind of preference to the disclosed embodiments.

[0020] As used herein, compositions and materials are used interchangeably unless otherwise specified. Each composition / material may have multiple elements, phases, and components. As used herein, heating refers to the active addition of energy to a composition or material.

[0021] 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.

[0022] In this disclosure, the absence of substantial amounts of H2 means that the volumetric 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.

[0023] 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:CeO2). Unless otherwise specified, CGO and GDC are used interchangeably. Syngas (i.e., synthesis gas) in this disclosure refers to a mixture consisting primarily of hydrogen, carbon monoxide, and carbon dioxide.

[0024] 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.

[0025] In this disclosure, the axial cross-section of the tubular portion is shown to be circular, but this is by way of example and not limitation, the axial cross-section of the tubular portion may be any suitable shape, such as a square, a square with rounded corners, a rectangle, a rectangle with rounded corners, a triangle, a hexagon, a pentagon, an ellipse, an irregular shape, etc., as known to those skilled in the art.

[0026] 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 oxide, including all oxidation states of chromium oxide.

[0027] As used herein, a layer or material that is impermeable refers to one that is impermeable to the flow of fluids. For example, an impermeable layer or material has a permeability of less than 1 microdarcy, or less than 1 nanodarcy.

[0028] In this disclosure, sintering refers to a process for forming a solid mass of a material by heat or pressure, or a combination thereof, without melting the material to the extent that it becomes liquid. For example, material particles are heated to coalesce into a solid or porous mass, and atoms within the material particles diffuse across the boundaries of the particles, fusing the particles together to form one solid piece.

[0029] The term "in situ" in this disclosure refers to a treatment (e.g., heating or decomposition) process that is carried out either at the same location or within the same device. For example, ammonia decomposition that occurs within an electrochemical reactor at the anode is considered in situ.

[0030] Electrochemistry is the branch of physical chemistry concerned with the relationship between electrical potential as a measurable and quantitative phenomenon and an identifiable chemical change, where the electrical potential is either the result of a particular chemical change or vice versa. These reactions involve electrons moving between electrodes through electronically conducting phases (typically, but not necessarily, an external electric circuit) separated by ionically conducting and electronically insulating membranes (or ionic species in solution). When a chemical reaction is influenced by a potential difference, such as during electrolysis, or when an electrical 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 the resulting ions) are not transferred directly between molecules, but through the aforementioned electronically and ionically conducting circuits, respectively. This phenomenon distinguishes electrochemical reactions from chemical reactions.

[0031] In connection with the electrochemical reactor and method of use, various components of the reactor, such as electrodes and membranes, are described, along with the materials of construction of the components. The following description details 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 that fall within the scope of the claimed invention. This description should be read from the perspective of one skilled in the art. Thus, information known to one skilled in the art is not necessarily included.

[0032] Interconnects in electrochemical devices (e.g., fuel cells) are often either metal or ceramic 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.

[0033] Electrochemical Reactors Unlike the past, electrochemical reactors have been found that include ionically conductive membranes that can electrochemically reform hydrocarbons or electrochemically perform a 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 forward water-gas shift reactions, or reverse water-gas shift reactions, or both. These differ from traditional reforming and water-gas shift reactions via chemical routes because they involve direct binding of reactants.

[0034] FIG. 1 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 includes H2, ammonia, syngas, or a combination thereof. The stream 104 does not contain oxygen. The second electrode 102 is configured to receive carbon dioxide (CO2), as shown at 105.

[0035] In one embodiment, the device 100 is configured to receive H2 (104) and produce H2O (106) at the first electrode (101), and the device 100 is also configured to receive CO2 (105) and produce CO (107) at the second electrode (102). In some cases, the second electrode also receives a small amount of CO. CO2 is considered the oxidant in this scenario because it provides the oxide ions (transported through the membrane) necessary to oxidize H2 at the opposite electrode. Reduction of CO2 produces CO. Thus, the first electrode 101 is performing an oxidation reaction in a reducing environment, and the second electrode 102 is performing a reduction reaction in a reducing environment. In some cases, such environments are nominally considered reducing environments. In various embodiments, both electrodes are exposed to a reducing environment during the production of carbon monoxide by the reactor. In some embodiments, both the anode and the cathode are exposed to reducing conditions during the entire operation of the reactor.

[0036] In various embodiments, 103 represents an oxide ion conducting membrane. In one embodiment, the first electrode 101 and the second electrode 102 comprise Ni-YSZ or NiO-YSZ. In one embodiment, the oxide ion conducting membrane 103 also conducts electrons. In various embodiments, the 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 the membrane 103 / electrode 101. The reformer is configured to perform steam reforming, dry reforming, or a combination thereof. The reformed gas is suitable as the feed stream 104.

[0037] In one embodiment, the anode and cathode and the membrane have the same elements. For example, the anode and cathode and the membrane include Ni-YSZ. In one embodiment, the anode and cathode and the membrane include LaSrFeCr (lanthanum strontium iron doped chromite)-SSZ (scandia stabilized zirconia). In one embodiment, the anode and cathode and the membrane include LaSrFeCr-SCZ (Sc and Ce stabilized zirconia).

[0038] In this disclosure, no oxygen means that there is no oxygen present 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 ingredient 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. Water also does not require 100% pure water, but includes this embodiment.

[0039] In various embodiments, the device does not contain a current collector. 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 the present disclosure. The membrane 103 is configured to conduct electrons and is therefore mixed conducting, i.e., both electronically and ionically conducting. In one embodiment, the membrane 103 conducts oxide ions and electrons. In one embodiment, the electrodes 101, 102 and membrane 103 are tubular (see, e.g., Figures 2A and 2B). In one embodiment, the electrodes 101, 102 and membrane 103 are planar. In these embodiments, the electrochemical reaction at the electrodes is spontaneous without the need to apply a potential / electricity to the reactor.

[0040] 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, the first electrode and the second electrode comprising a metal phase that does not contain platinum group metals 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 one embodiment, the second electrode is configured to receive CO2 (including small amounts of CO) and is configured to reduce CO2 to CO. In various embodiments, such reduction is performed electrochemically.

[0041] In one embodiment, the membrane comprises an electronically conductive phase containing doped lanthanum chromite, or an electronically conductive metal, or a combination thereof, and the membrane 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.

[0042] 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, 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. In one embodiment, the membrane 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, the LST comprises LaSrCaTiO3. In one embodiment, the membrane comprises nickel, copper, cobalt, or niobium doped zirconia.

[0043] In one embodiment, the membrane comprises cobalt-CGO (CoCGO), i.e., cobalt-doped CGO. In one embodiment, the membrane consists essentially of CoCGO. In one embodiment, the membrane consists of CoCGO. In one embodiment, the membrane comprises LST (lanthanum doped strontium titanate)-YSZ, or LST-SSZ, or LST-SCZ (scandiaceria stabilized zirconia). In one embodiment, the membrane consists essentially of LST-YSZ, or LST-SSZ, or LST-SCZ. In one embodiment, the membrane consists of LST-YSZ, or 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 interpenetrate. In this disclosure, LST-SSZ refers to a composite of LST and SSZ. In various embodiments, the LST and SSZ phases interpenetrate. In this disclosure, LST-SCZ refers to a composite of LST and SCZ. In various embodiments, the LST and SCZ phases interpenetrate each other. YSZ, SSZ, and SCZ are types of stabilized zirconia.

[0044] FIG. 2A illustrates a tubular electrochemical (EC) reactor or EC gas generator 200 (not to scale) 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 a cross-sectional view (not to scale) 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 fluid passage.

[0045] In one embodiment, the electrodes and membrane are tubular, the first electrode is outermost and the second electrode is innermost, and the second electrode is configured to receive CO. In one embodiment, the electrodes and membrane are tubular, the first electrode is innermost and the second electrode is outermost, and the second electrode is configured to receive CO. In one embodiment, the electrodes and membrane are tubular.

[0046] The electrochemical reactions occurring within the reactor include electrochemical half-cell reactions, which in various embodiments occur at a three-phase boundary, the three-phase boundary being the intersection of the electronically and ionically conducting phases with the pores.

[0047] 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 an interconnect.

[0048] Electrochemical CO generation An EC reactor as discussed above is suitable for producing CO from CO. In one embodiment, the reactor comprises porous electrodes 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 electrolysis device or from any fuel cell.

[0049] As illustrated in FIG. 3A, a CO generation system 300 is shown. The system 300 includes an EC rectifier 331, a fuel source 311, a carbon dioxide source 321, and a separator 341. 301 represents the anode in the reactor, and 302 represents the cathode in the reactor. 303 represents the membrane between the electrodes in the reactor. A first stream 392 containing fuel passes through the anode 301, is oxidized, and exits the anode as stream 393. A second stream 394 from the CO2 source 321 passes through the cathode 302, where CO2 is reduced to CO. A cathode exhaust stream 395 passes through the separator 341, where CO is separated from CO2. A product stream 396 exits the separator 341 and consists essentially of CO. A portion of stream 395 or stream 396 can be recycled to the cathode 302 (not shown in FIG. 3A). In some embodiments, both the anode and the cathode are exposed to the reducing environment during operation of the reactor. In some embodiments, both electrodes are exposed to the reducing environment simultaneously during production of carbon monoxide by the reactor. In various embodiments, both electrodes are exposed to the reducing environment during the entire time of operation.

[0050] The disclosed CO production process and system have various advantages: CO production from CO2 is desirable because it reduces greenhouse gas emissions. Producing CO on-site is inherently safer than transporting CO in pressurized vessels or conduits. The disclosed process utilizes an efficient electrochemical pathway yet does not require electricity. CO / CO2 separation from the cathode exhaust is easy and inexpensive. Thus, the disclosed method and system are cost-competitive in both capital equipment and operational costs.

[0051] Electrochemical generation of valuable products As illustrated in FIG. 3B, a chemical production system 300 is shown. The system 301 includes two EC rectifiers 331 and 332, a fuel source 311, a carbon dioxide source 321, a water source 322, a first separator 341, and a second separator 342. 301 represents the anode in the first reactor 331, and 302 represents the cathode in the first reactor 331. 303 represents the membrane between the electrodes 301 and 302 in the first reactor 331. 304 represents the anode in the second reactor 332, and 305 represents the cathode in the second reactor 332. 306 represents the membrane between the electrodes 304 and 305 in the second reactor 332.

[0052] A first fuel stream 313 containing a fuel passes through the anode 301, is oxidized, and exits as stream 315. A second fuel stream 312 containing a fuel passes through the anode 304, is oxidized, and exits as stream 314. In various embodiments, the fuel includes ammonia, syngas, hydrogen, methanol, carbon monoxide, or combinations thereof.

[0053] For the first reactor 331, stream 323 from a CO2 source 321 passes through the cathode 302 where CO2 is electrochemically reduced to CO. Cathode exhaust stream 343 passes through a first separator 341 where CO is separated from the CO2. Product stream 345 exits the first separator 341 and consists essentially of CO. A portion of stream 343 or a portion of stream 345 may be recycled to the cathode 302 (not shown in FIG. 3B).

[0054] For the second reactor 332, stream 324 from H2O source 322 passes through cathode 305 where H2O is electrochemically reduced to H2. Cathode exhaust stream 344 passes through second separator 342 where H2O is separated from H2O. Product stream 346 exits second separator 342 and consists essentially of H2. A portion of stream 344 or a portion of stream 346 may be recycled to cathode 305 (not shown in FIG. 3B). In some embodiments, the anode and cathode of both electrochemical reactors are both exposed to a reducing environment during operation of the reactor. In some embodiments, both electrodes of the first reactor are exposed to a reducing environment simultaneously during production of carbon monoxide by the reactor or during the entire operation of the first reactor. In some embodiments, both electrodes of the second reactor are exposed to a reducing environment simultaneously during production of hydrogen by the reactor or during the entire operation of the second reactor. In various embodiments, both electrodes of both EC reactors are exposed to a reducing environment during the entire time of operation.

[0055] The chemicals production system 301 may further comprise a chemicals generator selected from the group consisting of a Fischer-Tropsch reactor, a methanol generator, an ethanol generator, a hydrocarbon generator, a plastic monomer generator, and combinations thereof (not shown in FIG. 3B). The Fischer-Tropsch reactor may generate valuable products such as naphtha, gasoline, diesel, wax, etc. The generated methanol may be further converted to gasoline, ethylene, acetic acid, formaldehyde, methyl acetate, polyolefins, dimethyl ether (DME), or combinations thereof. In various embodiments, the chemicals generator is configured to receive carbon monoxide from the first separator and hydrogen from the second separator. Additionally, the system may comprise a polymerization unit for converting the plastic monomers into various types of plastics. Configurations and arrangements for utilizing the generated CO and H2 are known to those skilled in the art, and all such configurations and arrangements are within the scope of the present disclosure.

[0056] It is to be understood that the present disclosure describes exemplary embodiments for implementing different features, structures, or functions of the present invention. Although exemplary embodiments of components, arrangements, and configurations are described to simplify the present disclosure, these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the present invention. The embodiments as presented herein may be combined unless otherwise specified. Such combinations do not depart from the scope of the present disclosure.

[0057] Additionally, certain 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. Moreover, the terminology and naming conventions used herein are not intended to distinguish between components, features, and / or steps that differ in name but not function.

[0058] While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof are 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. A method for producing carbon monoxide, (a) To provide an electrochemical reactor having an anode, a cathode, and a mixed conductive film between the anode and the cathode, wherein both the anode and the cathode contain Ni; (b) Introducing a first flow into the anode, wherein the first flow contains fuel; (c) Introducing a second flow into the cathode, wherein the second flow contains carbon dioxide and carbon monoxide, the amount of carbon monoxide in the second flow is less than the amount of carbon dioxide, and the carbon monoxide is electrochemically generated from the carbon dioxide; A method comprising the reactor not generating electricity and not accepting electricity.

2. The method according to claim 1, wherein the fuel comprises ammonia, syngas, hydrogen, methanol, carbon monoxide, or a combination thereof.

3. The method according to claim 1, wherein the cathode generates cathode exhaust, the cathode exhaust passes through a separator, and the generated carbon monoxide is separated from carbon dioxide.

4. The method according to claim 1, wherein the anode and the cathode are separated by the membrane and both are exposed to a reducing environment for the entire duration of operation.

5. The method according to claim 1, wherein the anode and the cathode have the same element.

6. The method according to claim 1, wherein the anode, the cathode, and the film have the same elements.

7. The method according to claim 6, wherein the anode, the cathode, and the film include Ni-YSZ, LaSrFeCr-SSZ, or LaSrFeCr-SCZ.

8. The method according to claim 1, wherein the anode and the cathode each include Ni or NiO and a material selected from the group consisting of YSZ, CGO, SDC, SSZ, LSGM, CoCGO, and combinations thereof.

9. The method according to claim 1, wherein the film comprises an electronically conductive phase and an ionically conductive phase.

10. The method according to claim 9, wherein the electronically conductive phase includes doped lanthanum chromite or an electronically conductive metal, or a combination thereof, and the ionically conductive phase includes 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.

11. The method according to claim 1, wherein the film comprises CoCGO or LST (lanthanum-doped strontium titanate) stabilized zirconia.

12. The stabilized zirconia includes YSZ, SSZ, or SCZ (scandiacelia stabilized zirconia), and the LST is LaSrCaTiO ３ The method according to claim 11, including the method described in claim 11.

13. The method according to claim 1, wherein the film comprises nickel, copper, cobalt, or niobium-doped zirconia.

14. A method for producing valuable products, (a) To provide two electrochemical reactors, each having an anode, a cathode, and a mixed conductive film between the anode and the cathode, wherein both the anode and the cathode contain Ni; (b) Introducing a fuel flow into each of the anodes; (c) CO ２ The contained flow is introduced into the first cathode, H ２ Introducing an O-containing flow into a second cathode, where the first cathode generates a first cathode exhaust flow, the second cathode generates a second cathode exhaust flow, and the CO-2-containing flow introduced into the first cathode contains carbon monoxide, the amount of which is less than that of carbon dioxide; A method comprising the following: carbon monoxide is electrochemically generated from carbon dioxide, hydrogen is electrochemically generated from water, and the reactor does not generate or accept electricity.

15. CO from the first cathode exhaust flow ２ Separated from H ２ However, H from the second cathode exhaust flow ２ The method according to claim 14, wherein O is separated.

16. The separated CO and the separated H ２ The method according to claim 15, comprising using to produce methanol, ethanol, hydrocarbons, plastic monomers, polyethylene, or a combination thereof.

17. The method according to claim 14, wherein the anode and the cathode are separated by the membrane, and all are exposed to a reducing environment for the entire duration of operation.

18. The method according to claim 14, wherein the film comprises CoCGO or LST (lanthanum-doped strontium titanate) stabilized zirconia.

19. The stabilized zirconia includes YSZ, SSZ, or SCZ (scandiacelia stabilized zirconia), and the LST is LaSrCaTiO ３ The method according to claim 18, including the method described in claim 18.

20. The method according to claim 14, wherein the film comprises nickel, copper, cobalt, or niobium-doped zirconia.

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