Carbon oxide electrolysis integrated with naphtha reforming

Abstract

A system includes a carbon dioxide reduction electrolyzer comprising a cathode configured to electrochemically reduce carbon dioxide, a liquid hydrocarbon synthesis system configured to produce naphtha and at least one other hydrocarbon fuel, a naphtha reforming unit, and optionally a gas purification unit.

Description

Docket No. OPUSP049WOCARBON OXIDE ELECTROLYSIS INTEGRATED WITH NAPHTHA REFORMINGINCORPORATION BY REFERENCE

[0001] A PCT Request Form is filed concurrently with this specification as part of the present application. Each application that the present application claims benefit of or priority to as identified in the concurrently filed PCT Request Form is incorporated by reference herein in their entireties and for all purposes.TECHNICAL FIELD

[0002] The present disclosure is related to carbon oxide electrolysis integrated with naphtha reforming. The subject matter of the present disclosure involves, in some cases, interrelated products, alternative solutions to a particular problem, and / or a plurality of different uses of one or more systems and / or articles.BACKGROUND

[0003] Typical systems for producing liquid hydrocarbons, such as sustainable aviation fuels, generally separate the desired product hydrocarbons from the less desirable by-product hydrocarbons, for example, by fractionation. Depending on market conditions, the by-products may be considerably less valuable as a product or ultimately burned off as waste or fuel gas.

[0004] Thus, there is a need for systems and methods of increasing the yield of the more desirable hydrocarbon products.SUMMARY

[0005] This summary is provided to introduce some concepts in simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter.

[0006] In certain aspects, a method is provided. In some embodiments, the method comprises electrochemically reducing carbon dioxide (CO2) to carbon monoxide (CO) using a carbon dioxide reduction electrolyzer; introducing hydrogen gas (H2) and at least a portion of the CO produced by the carbon dioxide reduction electrolyzer to a liquid hydrocarbon synthesis system to produce liquid hydrocarbon products, the liquid hydrocarbon products comprising naphtha and at least one other liquid hydrocarbon product; reforming at least a portion of the naphtha produced by the liquid hydrocarbon synthesis system in a naphtha reforming unit to produceDocket No. OPUSP049WO syngas; and introducing at least a portion of the syngas produced by the naphtha reforming unit to the liquid hydrocarbon synthesis system.

[0007] In certain aspects, an integrated system is provided. In some embodiments, the system comprises a carbon dioxide reduction electrolyzer configured to electrochemically reduce carbon dioxide (CO2) to carbon monoxide (CO); a liquid hydrocarbon synthesis system downstream the carbon dioxide reduction electrolyzer and configured to produce liquid hydrocarbon products from hydrogen gas (H2) and at least a portion of the CO produced by the carbon dioxide reduction electrolyzer, the liquid hydrocarbon products comprising naphtha and at least one other liquid hydrocarbon product; and a naphtha reforming unit downstream the liquid hydrocarbon synthesis system, wherein the naphtha reforming unit is configured to produce syngas from the naphtha produced by the liquid hydrocarbon synthesis system and transport at least a portion of the produced syngas to the liquid hydrocarbon synthesis system.

[0008] Any combination of the above features may be implemented together in the above method aspects of this disclosure.

[0009] These and other features of the disclosure will be described in detail below, sometimes with reference to associated figures.BRIEF DESCRIPTION OF THE FIGURES

[0010] Figure 1 is a flow chart representation of an embodiment of the method.

[0011] Figures 2A and 2B are a schematic representation of an embodiment of the system and a variation of the embodiment, respectively.

[0012] Figures 2C and 2D are schematic representations of a first and second example, respectively, of the embodiment of the system.

[0013] Figure 3 depicts a system including a carbon dioxide electrolyzer configured to produce syngas.

[0014] Figure 4A depicts a Fischer-Tropsch system configured to produce liquid hydrocarbons in which a source of carbon is a carbon oxide feedstock such as one containing carbon dioxide and / or carbon monoxide.

[0015] Figure 4B depicts a Fischer-Tropsch system configured to produce liquid hydrocarbons in which a source of carbon is a carbon oxide feedstock and tail gas from the system reformed to produce addition carbon monoxide and hydrogen.

[0016] Figure 5 depicts a system for purifying a carbon monoxide stream containing carbon dioxide and possibly other components such as hydrogen.Docket No. OPUSP049WO

[0017] Figure 6 illustrates a hybrid carbon monoxide purification system having a cryogenic preprocessing subsystem and a sorbent postprocessing subsystem.

[0018] Figure 7 depicts an integrated system employing a carbon dioxide reduction electrolyzer and water electrolyzer that may act in concert to produce a syngas that is provided to a Fischer-Tropsch reactor to produce a fuel such as an aviation turbine fuel.

[0019] Figure 8 depicts an integrated system, similar to that in Figure 7, for producing a fuel, but the integrated system additionally includes, inter alia, units for reforming tail gas to produce more syngas for the Fischer-Tropsch reactor.

[0020] Figure 9A depicts an integrated system employing a carbon oxide reduction electrolyzer, a liquid hydrocarbon synthesis system, and a naphtha reforming unit that may be employed to recycle the naphtha produced by the liquid hydrocarbon synthesis system.

[0021] Figure 9B depicts an integrated system employing a naphtha reforming unit utilizing an external heater for oxy-combustion.

[0022] Figure 9C depicts an integrated system employing a naphtha reforming unit utilizing an external heater for combustion using air as a feed.

[0023] Figure 10A depicts an integrated system, similar to that in Figure 7, for producing fuel, but the integrated system additionally includes, inter alia, units for reforming naphtha to produce more syngas for the Fischer-Tropsch reactor.

[0024] Figure 10B depicts an integrated system, similar to that in Figure 10A, for producing a fuel, but the integrated system additionally includes, inter alia, production and recycling of CO2 from the naphtha reforming unit to the carbon dioxide reduction electrolyzer.

[0025] Figure 10C depicts an integrated system, similar to that in Figure 10B, for producing a fuel, but the integrated system additionally includes, inter alia, gas purification units for purifying both syngas and CO2 produced from the naphtha reforming unit.

[0026] Figure 10D depicts an integrated system, similar to that in Figure 10A, for producing a fuel, but the integrated system additionally includes, inter alia, a unit for reforming tail gas and a unit for reforming naphtha to produce more syngas for the Fischer-Tropsch reactor.DESCRIPTION

[0027] The following description of the preferred embodiments is not intended to limit the disclosure to these embodiments, but rather to enable any person skilled in the art to make and use this disclosure.Docket No. OPUSP049WO1. Overview

[0028] A system and / or method for carbon dioxide reactor control may be configured to control aspects of reactor production, such as aspects relating to quantity, concentration, and / or ratios of reactor products. Electrochemical carbon oxide reduction cells may be integrated with any of various other chemical processing systems such as chemical reactors, chemical separation units, purification units, and the like, along with associated sensing and / or control systems. Integrated systems may employ an electrochemical carbon oxide reduction cell and another chemical processing system disposed upstream, downstream, or in parallel with the electrochemical carbon oxide reduction cell.

[0029] Examples of carbon oxide reactants include carbon dioxide and carbon monoxide, typically though not necessarily in gaseous form. Other examples of carbon oxide reactants include carbonate ions and compounds, and bicarbonate ions and compounds.

[0030] Typical systems and methods for carbon dioxide reactor control have focused on maximization of aspects relating to production of carbon monoxide (CO) and / or other carbon- containing products (CCPs) (e.g., carbon-containing species (CCSs)), such as maximizing ratios of CO to other reactor products (e.g., CO:H2 ratio), CO concentration, and / or total CO output or output rate.

[0031] However, for some applications, simply maximizing aspect values can be undesirable, and that arbitrary control of such aspects (e.g., dynamic or selective aspect control to meet a value within a range of target aspect values), rather than simple maximization, can be beneficial. For example, it can be desirable to selectively control the CO:H2 ratio of the reactor products (e.g., enabling arbitrary control within a spectrum from the highest CO:H2 ratio possible for a given system and / or process, down to approximately 1:3 CO:H2 or lower). With such control, the reactor output can be more effectively used (e.g., wherein the reactor outputs are directly fed to a subsequent input) for applications such as liquid hydrocarbon production via the Fischer-Tropsch process (e.g., controlling the reactor to produce an approximately 1:2 CO:H2 output ratio), chemical synthesis processes, and / or gas (e.g., syngas) fermentation processes (e.g., bioreactors).2. System

[0032] The system can include a carbon dioxide reactor, such as a reactor that generates carbon-containing products (e.g., CO, alkanes, alcohols, etc.) and / or hydrogen from an input (e.g., an input stream, such as a fluid stream) that includes carbon dioxide. Example carbon oxide electrolyzers are illustrated in Figures 2A-2D. The reactor may be configured to accept a gas-phase carbon dioxide input and / or performs the reaction(s) using gas-phase carbonDocket No. OPUSP049WO dioxide (e.g., is a gas-phase reactor), but can additionally or alternatively accept liquid-phase carbon dioxide, supercritical fluid-phase carbon dioxide, solid-phase carbon dioxide, and / or any other suitable carbon dioxide input. While the discussion herein focuses on carbon dioxide reactors, in many cases the discussion applies equally to carbon monoxide reactors (e.g., electrochemical carbon monoxide reduction reactors), and carbonate and / or bicarbonate reduction reactors. So, unless otherwise specified or clear from context, reference to carbon dioxide reactors is understood to more generally reference carbon oxide reactors. As indicated, the reactor may be an electrolyzer (e.g., electrochemical reactor), such as a gas-phase polymer- electrolyte membrane electrolyzer but can additionally or alternatively include any other suitable reactors.

[0033] The reactor may include one or more: electrodes (e.g., anode, cathode), catalysts (e.g., within and / or adjacent the cathode and / or anode), gas diffusion layers (e.g., adjacent the cathode and / or anode), and / or flow fields (e.g., defined within and / or adjacent the electrodes and / or gas diffusion layers, such as one or more channels defined opposing the cathode across the gas diffusion layer). In some embodiments, the reactor includes a membrane stack or membrane electrode assembly (MEA) having one or more polymer electrolyte membranes (PEMs), providing ionic communication between the anode and cathode of the reactor. In certain embodiments, the reactor includes a membrane stack including: a cathode layer including a reduction catalyst and an ion-conducting polymer; a PEM membrane (e.g., bipolar membrane, monopolar membrane, etc.; membrane including one or more anion conductors such as anion exchange membranes (AEMs), proton and / or cation conductors such as proton exchange membranes, and / or any other suitable ion-conducting polymers; membrane including one or more buffer layers, etc.); and an anode layer including an oxidation catalyst and an ionconducting polymer. The ion-conducting polymers of each layer can be the same or different ion-conducting polymers.

[0034] In some embodiments, one or more of the catalysts (e.g., reduction catalyst, oxidation catalyst) can include catalyst particles (e.g., defining a porous network of particles), such as nanoparticles. One or more of the catalysts can additionally or alternatively include one or more polymer electrolytes, optionally wherein the polymer electrolyte is mixed with the catalyst nanoparticles (e.g., arranged within the porous network, such as loaded into the open regions defined by the porous network). The catalyst nanoparticles can define one or more characteristic sizes (e.g., mean size, median size, minimum size, maximum size, size at a particular percentile of the particle size distribution, etc.), and / or the porous network can define a porosity (e.g., fraction of empty space within the network), density, circuitousness (e.g.,Docket No. OPUSP049WO characteristic path length per layer thickness, area, and / or volume, such as path through the empty spaces or path along interconnected particles, etc.), and / or any other suitable porous network metrics.

[0035] In some configurations, a bipolar MEA has the following stacked arrangement: cathode layer / cathode buffer layer (an anion conducting layer) / cation conductive layer (which may be a PEM) / anode layer. In some implementations, the bipolar MEA has a cathode layer containing an anion conductive polymer and / or an anode layer containing a cation conductive layer. In some implementations, the bipolar MEA has an anode buffer layer, which may contain a cation conductive material, between the cation conductive layer and the anode layer.

[0036] In some configurations, a bipolar MEA has the following stacked arrangement: cathode layer / cation conducting layer (which may be a PEM) / anion conductive layer / anode layer. In some applications, a bipolar MEA having this arrangement is configured in a system for reducing a carbonate and / or bicarbonate feedstock such as an aqueous solution of carbonate and / or bicarbonate.

[0037] In some configurations, an MEA has the following stacked arrangement: cathode layer / anion conducting layer / anode layer. In some implementations, this MEA has no cation conductive layers between the cathode layer and the anode layer. In some applications, an MEA containing only anion conductive material between the cathode and anode is configured in a system for reducing carbon monoxide feedstock.

[0038] In one example (“reactor configuration A”), the system includes: a carbon fiber paper gas diffusion layer (e.g., Sigracet 39BC); a catalyst layer including approximately 20% by weight of approximately 4 nm gold particles on Vulcan carbon and an anion-conducting polymer (e.g., Fumasep FAA-3); a bipolar PEM; and a flow field such as a single, double, triple, or quadruple serpentine flow field or an interdigitated flow field. In a specific example, the electrodes define an area of approximately 25 cm2, but can additionally or alternatively define any other suitable area.

[0039] In some embodiments, the reactor includes one or more elements such as described in U.S. Patent Application serial number 15 / 586,182, filed 03-MAY-2017 and titled “Reactor with Advanced Architecture for the Electrochemical Reaction of CO2, CO and Other Chemical Compounds”, which is hereby incorporated in its entirety by this reference. However, the reactor can additionally or alternatively include any other suitable elements in any suitable arrangement.

[0040] Additional information regarding optional embodiments and / or elements of the system and / or method are provided below, in US Patent Application Publication No. 2017 / 0321334,Docket No. OPUSP049WO filed May 3, 2017, and in US Provisional Patent Application No. 62 / 939,960, filed November 25, 2019, which are incorporated herein by reference in their entireties.

[0041] A carbon oxide reduction reactor may comprise more than one cells or MEAs. The multiple cells or MEAs may be arranged in a stack, electrically connected to one another in series and / or parallel. Unless otherwise indicated, all references herein to a carbon oxide reduction reactor, a carbon oxide electrolyzer, and the like embody single cell electrolyzers and multicell stacks of electrolyzers.

[0042] A carbon oxide reduction reactor may obtain carbon oxides from various sources. As mentioned, examples of carbon oxide reactants include carbon dioxide, carbon monoxide, carbonate, and / or bicarbonate. In certain embodiments, a carbonate or bicarbonate is provided in the form of an aqueous solution (e.g., an aqueous solution of potassium bicarbonate) that can be delivered to the cathode of a reduction cell. Carbonates and bicarbonates may be obtained from various sources (e.g., minerals) and / or by various reactions (e.g., reacting carbon dioxide with hydroxide).

[0043] A system may optionally include an upstream source of carbon dioxide input, connected to an input of a carbon dioxide reactor of the disclosure, including one or more of: a biogas production system; an ethanol fermentation system such as com ethanol production system, a beer production system, a wine production system; a natural gas processing system; a cement production system; a blast furnace system, for example a steel blast furnace system, capable of producing blast furnace gas; a coke gas production system; power plant systems, such as petroleum power plant systems, natural gas power plant systems, coal power plant systems; petroleum refinery systems; ethylene production systems; ammonia production systems; hydrogen production systems, such as water-gas shift systems; natural gas processing plants (e.g., Benfield processing); ethylene oxide production systems; aluminum smelting systems; liquified natural gas (LNG) production systems; solid feedstock gasifiers (e.g., municipal solid waste, biomass, or coal feedstocks); reformers (e.g., steam methane reformers, autothermal reformers); systems performing Boudouard reactions; direct air capture (DAC) of carbon dioxide process; atmospheres of planets or moons (e.g., the Martian atmosphere), soil of moons (e.g., the soil of the earth’s moon), and / or any other system capable of producing carbon dioxide. An upstream source of carbon dioxide may be connected directly to an input of a carbon dioxide reactor of the disclosure (e.g., serves as the input, such as connected to the reduction catalyst via the cathode flow field and / or gas diffusion layer, etc.) or alternatively the upstream source may be connected to a purification system; a gas compression system; or both a purification system and a gas compression system, in either order; which then connect to anDocket No. OPUSP049WO input of a carbon dioxide system of the disclosure. Multiple purification and / or gas compression systems (e.g., scrubbers, etc.) may be employed.

[0044] The carbon dioxide, carbon monoxide, or carbonate provided as input to a carbon oxide reduction reactor may, depending on the construction and operating conditions of the reactor, have a range of concentrations. In certain embodiments, carbon dioxide provided to a carbon dioxide reduction reactor has a concentration of at least about 20 mole percent, or at least about 40 mole percent, or at least about 75 mole percent, or at least about 90 mole percent. In certain embodiments, carbon dioxide provided to a carbon dioxide reduction reactor has a concentration of about 40 to 60 mole percent.

[0045] An upstream source of water for an electrolytic carbon oxide reduction reactor may come from any of various sources and in various forms such as purified tap water, purified sea water, a byproduct of direct air capture of water, optionally with capture of carbon dioxide, combustion processes that may also produce carbon dioxide feedstock, fuel cell byproduct, and the like.

[0046] A system may include an input of a downstream system, capable of transforming chemical outputs from a carbon dioxide reactor of the disclosure, connected to an output of a carbon dioxide reactor of the disclosure. As examples, a downstream system of the disclosure may include one or more of: a bioreactor system; a Fischer-Tropsch system; an anaerobic fermentation system; an aerobic fermentation system, a syngas fermentation system; a ketone and / or polyketone production system; a formate production system; a formate ester production system; a formamide production system; a hydroformylation system; a methanol synthesis system; an ethylene polymerization system; a phosgene production system, an isocyanate production system, a polymer (e.g., a polycarbonate, polyethylene terephthalate, or polyurethane) production system, a monoethylene glycol production system, a polyethylene glycol production system, and oxalic acid production system, and / or any other system capable of transforming chemical outputs from a carbon oxide reduction reactor. A carbon dioxide reactor output of the disclosure may be directly connected (e.g., via the cathode flow field and / or gas diffusion layer) to a downstream system, and / or the carbon dioxide reactor output may be connected to a purification system; a gas compression system; or both a purification system and a gas compression system, in either order; which then optionally connect to an input of a downstream system. Multiple purification systems and / or gas compression systems may be employed.

[0047] A downstream system may produce carbon dioxide output in addition to other product outputs. A system may further include a connection between a carbon dioxide-containingDocket No. OPUSP049WO output of a downstream system and an input of a carbon dioxide reactor. The carbon dioxide containing output of a downstream system may be directly connected to an input of a carbon dioxide reactor or alternatively the downstream carbon dioxide containing output may be connected to a purification system; a gas compression system; or both a purification system and a gas compression system, in either order; which then connect to an input of a carbon dioxide reactor of the disclosure. Multiple purification systems and / or gas compression systems may be employed.

[0048] A carbon dioxide reactor can make a range of products (for example, methane, ethylene, carbon monoxide (CO), molecular hydrogen (H2), ethanol, formate, formic acid, acetate, acetic acid, propanol, butanol, ethane, methanol) that can be used in downstream systems and processes. Different carbon dioxide reactors (e.g., including different layer stacks, catalysts and / or catalyst layers, PEMs, flow fields, gas diffusion layers, cell compression configurations, and / or any other suitable aspects, etc.) can be used to achieve different reduction products (e.g., product compositions such as HCR); however, different reduction products can additionally or alternatively be achieved by adjusting the operation parameters, and / or be otherwise achieved. Many possible downstream systems and processes release CO2 (examples include bioutilization of methane, bio-utilization of formic acid or formate, bio-utilization of acetic acid or acetate, Fischer-Tropsch processes, and methanol synthesis). A carbon dioxide recycling system sized appropriately for the specific application can be used in many of these cases to return CO2 from the downstream system output to an input of a carbon dioxide reactor of the disclosure to increase the carbon efficiency of the overall process.

[0049] A system may further include a source of electrical energy connected to a carbon dioxide reactor, the source of electrical energy comprising one or more of: a solar electrical energy production system; a wind electrical energy production system; a geothermal electrical energy production system; a fossil fuel electrical energy production system; or any other system capable of electrical energy production.

[0050] A system may be employed to store electrical energy in the form of chemical energy. For example, power producers may produce excess power during off-peak usage periods. Systems containing carbon oxide reduction reactors are able to respond quickly to a need to consume excess power. They do not need to warm up to operate, and they can be cycled between power on and power off states without deterioration of carbon dioxide reactors. The ability to respond quickly to power utilization needs allows systems to work well with intermittent sources of power such as solar electrical energy production systems, and wind electrical energy production systems.Docket No. OPUSP049WO

[0051] An embodiment of a system may include an upstream bioreactor, a carbon dioxide reactor, and an intermittent source of electrical energy. When electrical power is available from solar, wind, low off-peak demand, or other sources, a power availability detector may be used to start the carbon dioxide reactor. In addition, the system may boost the output of the upstream bioreactor by, for example, raising the temperature of the upstream bioreactor and increasing the flow of nutrients to the upstream bioreactor. For other upstream carbon dioxide sources, other means may be used as necessary to increase the flow of carbon dioxide to an input of a carbon dioxide reactor of the disclosure.

[0052] Any of the systems disclosed herein may include components (e.g., sensors, systems, etc.) to measure conditions, outputs, and inputs in the systems connected to a carbon dioxide reactor. Such components may include chemical property measurement systems such as gas chromatographs, mass spectrometers, infrared spectrometers, visible light spectrometers, and / or ultraviolet light spectrometers; temperature detectors; flow rate measurement sensors; electrical power availability detectors; and / or any other monitoring systems. The monitoring systems can monitor the parameters of the input and / or output streams, the parameters of a component of the input and / or output streams (e.g., the impurity concentration, the carbon dioxide concentration, the product concentration, etc.), and / or monitor any other suitable parameter(s) of the stream.

[0053] Any of the systems disclosed herein may include components for responding to conditions measured in systems connected to a carbon dioxide reactor. Such components may include systems for adjusting flow rates, temperatures, power consumption, or other system parameters. A system may include one or more carbon dioxide reactors. However, the system can additionally or alternatively include any other suitable elements in any suitable arrangement. In various embodiments, one or more monitoring or sensing components is used in conjunction with a control system including a controller with appropriately programmed or constructed logic (e.g., processors and memory) for determining that one or more operating conditions should be modified and causing such operating condition(s) to be modified. Feedforward and / or feedback control systems may be employed.3. Method

[0054] The method may be implemented using any of the components described above, including an electrochemical carbon oxide reduction reactor, but can additionally or alternatively be implemented using any other suitable system(s). The method optionally includes running the reactor under controlled process conditions (e.g., as described below in further detail) to produce the desired outputs (e.g., CO, H2, etc.) in the desired ratios (e.g.,Docket No. OPUSP049WO molecular hydrogen-to-CCP ratio (HCR) and / or CCP-to-molecular hydrogen ratio), and / or altering the process conditions to alter the outputs and / or output ratios (e.g., as shown in Figure 1).

[0055] Running the reactor can include: providing one or more inputs (e.g., gasses, liquids, solids, etc.), such as carbon dioxide, carbon monoxide, a carbon oxide source (e.g., waste gas), and / or water; causing all or some of the inputs to undergo reactions (e.g., by applying a voltage across the device electrodes), thereby generating products; and / or removing the products from the reactor (e.g., as an output gas stream). Such reactions can include, for example, reducing carbon dioxide and / or water to generate products such as CO (and / or other CCPs, such as formic acid, methanol, glyoxal, methane, acetic acid, glycolaldehyde, ethylene glycol, acetaldehyde, ethanol, ethylene, hydroxyacetone, acetone, allyl alcohol, propionaldehyde, n- propanol, etc.), and / or H2. However, running the reactor can additionally or alternatively include causing any other suitable reactions to occur, and / or can additionally or alternatively include any other suitable elements performed in any suitable manner.

[0056] The method can include controlling the system to achieve a desired set of process conditions (e.g., aspects), such as process conditions known to result in a desired output metric value (e.g., a desired CCP:H2 ratio, such as a CO:H2 ratio). The method can additionally or alternatively include altering process conditions, such as based on a difference between actual and desired outputs (e.g., to reduce or eliminate the difference). For example, the method can include: imposing an initial set of process conditions; monitoring one or more output metrics (e.g., CCP:H2 ratio); determining that an output metric differs from a target output metric (e.g., is greater than or less than the target); altering one or more process conditions to reduce the output metric difference (e.g., reducing or increasing a process condition value, such as a condition for which the output metric tends to increase or decrease along with an increasing process condition value); and optionally continuing to monitor the output metrics and / or alter the process conditions (e.g., implementing a closed-loop control of the process conditions based on the output metrics).

[0057] The method can optionally include determining the target output metric(s), which functions to determine which parameter(s) or aspect(s) to target (e.g., key parameter for a given application or downstream system). One or more target output metrics can be selected for a given process. The target output metric can be: the output metric associated with (e.g., predetermined for, dictated by, etc.) an application (e.g., applications described above, such as Fischer-Tropsch); randomly selected; empirically determined (e.g., through iterative testing and monitoring of downstream application performance); optimized (e.g., based onDocket No. OPUSP049WO downstream application operation parameters, reactor operation parameters, etc.); specified by a user; and / or otherwise determined.

[0058] The method can optionally include determining the target value for the target output metric, which functions to identify a value (from a range of values) to target. In some variations, the target value can be a maximum or minimum value (e.g., maximum or minimum practically achievable value, theoretical maximum or minimum, etc.). However, the target value can additionally or alternatively not be an extremal value (e.g., can be an intermediate value or range of values between the maximum and minimum). The target value can be: a value associated with the application (e.g., predetermined, pre- associated); randomly selected; empirically determined (e.g., through iterative target value selection, monitoring of downstream application performance, and target value adjustment based on the application performance); optimized (e.g., based on downstream application operation parameters, reactor operation parameters, etc.); or otherwise determined. However, the target value can be any other suitable value and can be determined in any suitable manner.

[0059] Under some conditions, the method may achieve carbon dioxide conversion (e.g., CO fractional yield) greater than 95% (e.g., up to 100%), such as wherein the system, run under such conditions, can achieve at least the threshold conversion metric. However, the method can additionally or alternatively include achieving carbon dioxide conversion greater than about 50%, greater than about 60%, greater than about 70%, greater than about 80%, greater than about 90%; or from about 10% to aboutl00%, from about 10% to about 40%, from about 30% to about 50%, from about 40% to about 60%, from about 50% to about 70%, from about 60% to about 75%, from about 70% to about 85%, from about 80% to about 95%, from about 90% to about 95%, from about 92% to about 98%, or from about 95% to about 100%; or any other suitable carbon dioxide conversion.

[0060] The method optionally includes providing the reactor products (or a subset thereof) to a downstream consumer of the products (e.g., as described above, such as regarding applications of the reactor output; as described below, such as in the example section; etc.). The method can optionally include altering the reactor products after they are produced (e.g., before feeding the altered products to a downstream consumer, etc.). Altering the reactor products can optionally include purifying the products (e.g., removing impurities, such as SOXand / or NOX, from a reactor output stream). Altering the reactor products can additionally or alternatively include mixing additional gases (and / or other substances) into a reactor output stream (and / or input stream), such as to achieve a desired output metric. In one variation, if the CO:H2 ratio of the reactor output differs from a desired value, the ratio can be adjusted byDocket No. OPUSP049WO mixing the reactor output with other gasses (e.g., substantially pure CO and / or H2; another mixture of CO and H2, such as previously produced and stored outputs of the reactor, the output of a second reactor, outputs and / or waste gasses of other systems, etc.). For example, the C0:H2 ratio of the output stream (and / or gases in any other portion of the reactor) can be monitored (e.g., continuously during reactor production), and deviations from the desired value can be compensated for by mixing in other gases (e.g., adding CO and / or a CO-rich mixture to increase the ratio, adding H2 and / or an H -rich mixture to decrease the ratio). This example may also include altering the process conditions in order to correct the reactor outputs (e.g., as described above regarding closed- loop control). In a second variation, in which an external gas supply (e.g., the outputs and / or waste gasses of one or more other system, such as a steel mill) is fed to a downstream consumer (e.g., a gas fermenter), the reactor products are used to alter the CCP:H2 ratio (e.g., COiFh ratio) of the external gas supply (e.g., if the CCPiFh ratio of the external gas supply differs from a desired value, mixing in the reactor products to achieve the desired value). For example, based on the deviation of the external gas supply from the desired value, the process conditions can be controlled to alter the COiFh ratio of the reactor products (e.g., increasing the ratio in response to a CO-poor external gas supply, decreasing the ratio in response to a CO-rich external gas supply), and / or the quantity of reactor product mixed into the external gas supply can be controlled (e.g., to achieve the desired value). However, the reactor output stream can additionally or alternatively be altered in any other suitable manner or can be used without alteration.

[0061] In some examples, the method includes determining one or more metrics (e.g., operation metrics) associated with the one or more upstream and / or downstream elements of the system (e.g., downstream reactors, upstream inputs, etc.). Such operation metrics can include, for example: reactor conditions such as temperature, pressure, etc.; downstream reactor and / or upstream source output metrics such as output quantity, composition, purity, etc.; metrics associated with other inputs for the downstream reactor(s), such as input quantity, composition, purity, etc.; reactor efficiency metrics; and / or any other suitable metrics. In such examples, the method may include altering carbon dioxide reactor operation based on the metrics (e.g., to improve and / or maintain operation of the downstream reactor; to improve and / or maintain operation of the carbon dioxide reactor, such as to accommodate changes in the upstream source; to improve and / or maintain a target output metric, such as HCR or reduction product concentration, such as given a varying carbon dioxide source; etc.), such as by altering the HCR of the carbon dioxide reactor output. However, the method canDocket No. OPUSP049WO additionally or alternatively include determining any other suitable metrics and / or acting (e.g., based on the metrics) in any other suitable manner.4. Process conditions

[0062] The process conditions can include, e.g., input carbon dioxide flow rate and / or pressure, input gas hydration, current density, voltage (e.g., maintained between about 1.5 V and 3 V, additionally or alternatively operated at less than about 1.5 V, between about 2 V-2.5 V, between about 2 V-4 V, greater than about 4 V, and / or at any other suitable voltage(s)), and / or temperature. The process conditions can additionally or alternatively include system configurations, such as gas diffusion layer aspects, catalyst aspects, flow field aspects, and / or PEM aspects. However, any other suitable process conditions can be controlled or targeted. The process condition can be uncontrolled (e.g., dictated by an upstream system), controlled to meet a target value (e.g., wherein the target value can be determined based on the application receiving the reactor output, the instantaneous or anticipated reactor operation parameters, or otherwise determined), or otherwise determined.

[0063] The process conditions may include a pressure (e.g., input gas pressure, reactor pressure, etc.) greater than atmospheric pressure (e.g., within and / or greater than a threshold pressure range, such as about 1-5, about 5-10, about 10-20, about 20-50, about 50-100, about 100-300, about 300-1000, about 1-10, about 5-50, about 10-100, about 20-500, and / or greater than about 1000 atm, about 14-50, about 50-150, about 100-300, about 200-500, about 500-1000, about 750-1500, about 1000-3000, about 3000-10,000, about 10,000-20,000, and / or greater than about 20,000 psi, etc.) and / or greater than pressures typically feasible in electrolyzers other than gas-phase electrolyzers, but can additionally or alternatively include pressures substantially equal to 1 atmosphere, less than about 1 atmosphere, and / or any other suitable pressures. The process conditions may include a temperature (e.g., reactor temperature) greater than typical room temperature (e.g., within and / or greater than a threshold temperature range, such as about 25-50, about 40-60, about 50-100, about 50-75, about 70- 100, and / or greater than about 100 °C, etc.) and / or greater than temperatures typically feasible in electrolyzers other than gas-phase electrolyzers, but can additionally or alternatively include temperatures substantially equal to room temperature (e.g., about 20-30 °C), less than room temperature, and / or any other suitable temperatures. However, the process conditions can additionally or alternatively include any other suitable process conditions.

[0064] A higher carbon dioxide flow rate can lead to increased production of CCPs such as CO (e.g., due to greater availability of carbon dioxide for reduction), and thus an increased CCP:H2 ratio (and correspondingly, a lower carbon dioxide flow rate can lead to decreasedDocket No. OPUSP049WOCCP production and CCP:H2 ratio). In some embodiments, a higher carbon dioxide flow rate can also result in reduced carbon dioxide conversion efficiency, thereby diluting the output stream (e.g., syngas output) with unreacted carbon dioxide. For example, carbon dioxide flow rate (e.g., measured at the reactor inlet) can be maintained at one or more values in the range of about 0.1-1000 sccm / cm2(e.g., about 0.1-1, about 1-10, about 10-100, and / or about 100- 1000 sccm / cm2).

[0065] In a first specific example of control based on input gas flow rate, reactor configuration A with a triple serpentine flow field is used, reactor pressure is substantially maintained at 120 psi, current density is substantially maintained at 500 mA / cm2, and reactor temperature is substantially maintained at 30 °C. In this specific example, substantially pure carbon dioxide gas is input at various flow rates, wherein input flow rates (e.g., measured at the reactor inlet) of 12 sccm / cm2, 20 sccm / cm2, and 40 sccm / cm2result in CO:H2 ratios of approximately 1:1, 2:1.1, and 4:1, respectively.

[0066] In a second specific example of control based on input gas flow rate, reactor configuration A with a serpentine flow field is used, reactor pressure is substantially maintained at 130 psi, and current density is substantially maintained at 500 mA / cm2. In this specific example, substantially pure carbon dioxide gas input at a 40 sccm / cm2flow rate results in a CO:H2 ratio of approximately 8:2, whereas a 12 sccm / cm2flow rate results in an approximately 1:1 ratio.

[0067] Higher carbon dioxide pressure can lead to increased CCP fractional yield and / or CCP:H2 ratio (and correspondingly, lower carbon dioxide pressure can lead to decreased CCP fractional yield and / or CCP:H2 ratio). First, increased carbon dioxide pressure can result in greater availability of carbon dioxide for reduction, thereby increasing the total production of CCPs. Second, higher pressure at the catalyst can reduce water ingress to the catalyst (e.g., from the cathode), thereby lowering the amount of water available for reduction, which can directly increase the CCP:H2 ratio and / or can reduce competition for catalyst reaction sites and / or reaction energy (e.g., thereby favoring reduction of carbon dioxide). Thus, in some embodiments (e.g., in which high CCP fractional yield and / or CCP:H2 ratio is desired), high reactor pressure (e.g., greater than 100 psi, up to but no greater than a carbon dioxide phase transition pressure, such as a critical pressure of 1070 psi, etc.) may be employed. For example, reactor pressure can be maintained at one or more values in the range of about 1-1100 psi (e.g., about 1-10, about 10-100, about 100-300, about 200-600, and / or about 500-1100 psi), and / or at any other suitable pressure.Docket No. OPUSP049WO

[0068] In a specific example of control based on reactor pressure, reactor configuration A with a single serpentine flow field is used, substantially pure carbon dioxide gas is input at about 100 sccm / cm2, current density is substantially maintained at about 150 mA / cm2, and reactor temperature is substantially maintained at about 20 °C. In this specific example, reactor pressure is substantially maintained at various pressures, wherein reactor pressures of 25, 50, 75, and 100 psi result in CO:H2 ratios of approximately 3:2, 2.4:1, 3:1, and 5:1 and CO fractional yields of approximately 59%, 69%, 75%, and 84%, respectively.

[0069] Increasing input gas hydration can lead to increased water reduction (e.g., due to greater availability of water for reduction), and thus to a decreased CCP:H2 ratio. For a substantially pure carbon dioxide input, only small amounts of water reach the catalyst (coming almost exclusively from the cathode side of the reactor), leading to a higher CCP:H2 ratio. In contrast, when hydrated input gas is used, significant amounts of water from the input gas can reach the catalyst and react. For example, input gas hydration (e.g., proportion of water vapor in the input gas) can be maintained at one or more values in the range of 0% (e.g., substantially pure carbon dioxide, substantially unhydrated input gas) to 100% (e.g., 0-1, 1-3, 3-5, 5-7, 7-10, 10-15, 15-25, 25-50, 50-75, and / or 75-100 percent).

[0070] In a specific example of control based on input gas hydration, reactor configuration A with a single serpentine flow field is used, current density is substantially maintained at 50 mA / cm2, reactor pressure is substantially maintained at 12 psi, and reactor temperature is substantially maintained at 20 °C. In this specific example, carbon dioxide gas with varying amounts of hydration is input at 100 sccm / cm2, wherein pure carbon dioxide input gas results in a CO:H2 ratio of approximately 3:2, input gas with 12.2% hydration results in a CChFh ratio of approximately 1:5.67, and intermediate hydration amounts result in CChFh ratios between these two values.

[0071] Reactors can exhibit different regimes of CCP and H2 production with respect to current density. In an idealized reactor, at low current densities, no water reduction occurs and all current goes to reducing carbon dioxide, resulting in a substantially linear dependence of CO production on current and substantially no H2 production; whereas at higher current densities, additional current (e.g., above a threshold current at which substantially all carbon dioxide is already being consumed) is used to reduce water, resulting in a substantially linear dependence of H2 production on the additional current and substantially constant CO production. In many typical reactors, these idealities are loosened, but the two general regimes are still exhibited: CO production increases much faster than H2 production in the low current density regime, then approaches a plateau in the higher current density regime while H2 production increasesDocket No. OPUSP049WO more rapidly. The method can include controlling CO and / or H2 production (e.g., controlling C0:H2 ratio) by operating at any or all of a wide range of current densities (e.g., controlling the reactor operation within the low and / or high current density regime, etc.). In some embodiments, the use of gas phase input carbon dioxide can enable relatively high current densities (whereas reactors using aqueous carbon dioxide may be limited to current densities of tens of mA / cm2or less). For example, the method can include operating at current densities between about 1 mA / cm2and 100 A / cm2(e.g., about 1-75 mA / cm2, about 50-100 mA / cm2, about 100-200 mA / cm2, about 200-500 mA / cm2, about 500-1000 mA / cm2, about 50-1000 mA / cm2, about 0.5-10 A / cm2, about 1-2 A / cm2, about 2-5 A / cm2, about 5-10 A / cm2, about 5-100 A / cm2, about 10-20 A / cm2, about 20-50 A / cm2, about 50-100 A / cm2, etc.; at, above, or below a threshold value such as about 50 mA / cm2, about 65 mA / cm2, about 80 mA / cm2, about 90 mA / cm2, about 100 mA / cm2, about 110 mA / cm2, about 120 mA / cm2, about 130 mA / cm2, about 140 mA / cm2, about 150 mA / cm2, about 200 mA / cm2, about 300 mA / cm2, about 500 mA / cm2, about 700 mA / cm2, about 1000 mA / cm2, about 1500 mA / cm2, etc.) and / or at any other suitable current densities.

[0072] In some embodiments, increased reactor temperature can result in a reduced CO:H2 ratio (e.g., due to increased ingress of water from the cathode, increased reactivity of water, etc.). The method can include controlling reactor temperature within an operation range, such as a range between a minimum temperature (e.g., a water freezing temperature such as 0 °C) and a maximum temperature (e.g., about 40 °C, about 50 °C, about 60 °C, about 75 °C, etc.; a water boiling temperature such as 100 °C), in order to control CO:H2 ratio and / or any other suitable output metrics.

[0073] In a specific example of control based on reactor temperature, reactor configuration A with a quadruple serpentine flow field is used, substantially pure carbon dioxide gas is input at 70 sccm / cm2, current density is substantially maintained at 150 mA / cm2, and reactor pressure is substantially maintained at 100 psi. In this specific example, reactor temperature is substantially maintained at various temperatures, wherein reactor temperatures of 26.7, 35, 38.7, and 41.9 °C result in CO:H2 ratios of approximately 1:0.4, 2:1, 1:1.8, and 1:3, respectively.

[0074] Characteristics of the gas diffusion layer (GDL) can additionally or alternatively be used to affect CCP and / or H2 production. For example, the GDL hydrophobicity can alter H2 production (e.g., by affecting water transport), wherein a more hydrophilic GDL favors H2 production (thereby reducing the CCP:H2 ratio) and a more hydrophobic GDL inhibits H2Docket No. OPUSP049WO production (thereby increasing the CCPiFh ratio). Other GDL characteristics, such as thickness and / or pore size, can also be used to alter the reactor output.

[0075] Characteristics of the membrane (e.g., polymer electrolyte membrane) can additionally or alternatively be used to affect CCP and / or H2 production. In examples, an anion exchange membrane, which favors CCP production, can be used to achieve high CCP:H2 ratios, a cation exchange membrane, which favors H2 production, can be used to achieve low CCP:H2 ratios, and hybrid membranes (e.g., enabling both anion and cation transport) exhibiting various anion and cation transport characteristics (e.g., mobilities) can be used to achieve various intermediate ratios (e.g., membranes favoring anion transport for higher ratios, membranes favoring cation transport for lower ratios).

[0076] Characteristics of the catalysts (e.g., particle size, catalyst species, etc.) can additionally or alternatively be used to affect CCP and / or H2 production. For example, larger catalyst particles can result in poor carbon dioxide transport, thereby inhibiting CCP production and reducing the CCP:H2 ratio, whereas smaller catalyst particles can favor CCP production, thereby increasing the ratio. The relative number of active sites with high turnover frequency for hydrogen evolution (“hydrogen sites”) and those with high turnover frequency for carbon dioxide reduction (“carbon dioxide sites”) can additionally or alternatively be dependent on catalyst particle size: larger catalyst particles typically have a higher ratio of hydrogen sites to carbon dioxide sites, favoring H2 production, whereas smaller catalyst particles typically have a lower ratio, favoring CO production. The catalyst type (e.g., catalyst species) can additionally or alternatively be used to control the reactor output, such as by employing a mixture of one or more catalyst materials, wherein a first set of catalyst materials (e.g., gold) favors carbon dioxide reduction and a second set of catalyst materials (e.g., platinum) favors water reduction. In examples, a substantially pure gold catalyst can be used to achieve high CCPiFh ratios, a substantially pure platinum catalyst can be used to achieve low CCPiFh ratios, and goldplatinum mixtures (e.g., alloyed particles, mixtures of gold particles and platinum particles, etc.) of varying composition can be used to achieve various intermediate ratios (e.g., more gold for higher ratios, more platinum for lower ratios). The catalyst can additionally or alternatively include V, Cr, Mn, Fe, Co, Ni, Cu, Sn, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Ir, Hg, Al, Si, In, Ga, Tl, Pb, Bi, Sb, Te, Sm, Tb, Ce, Nd, and / or combinations thereof. The catalyst can additionally or alternatively be associated with (e.g., attached to, supported by, embedded in, adjacent, in contact with, etc.) one or more support structures (e.g., support particles, support matrix, etc.), which may be conductive support structures such as carbon, boron-dopedDocket No. OPUSP049WO diamond, and / or fluorine-doped tin oxide. However, the catalyst can additionally or alternatively include any other suitable materials.

[0077] In a specific example of control based on catalyst particle size, variations of reactor configuration A with two catalyst particle sizes are used, both with reactor temperature substantially maintained at 30 °C, reactor pressure substantially maintained at 100 psi, an interdigitated flow field, substantially pure carbon dioxide gas input at 10 sccm / cm2, and current density substantially maintained at 500 mA / cm2. The first set of catalyst particles have a characteristic size of 4 nm (as in the standard reactor configuration A), resulting in an HCR of 1:1.6 and a voltage of 3.8 V. The second set of catalyst particles have a characteristic size of 20 nm, resulting in an HCR of 1:2.8 and a voltage of 4.2 V.

[0078] Characteristics of reactor cell compression can additionally or alternatively be used to affect CCP and / or H2 production. In a specific example of control based on reactor cell compression, reactor configuration A is used with two different gasket thicknesses (resulting in greater compression for a larger gasket thickness), both with reactor temperature substantially maintained at 30 °C, reactor pressure substantially maintained at 100 psi, a triple serpentine flow field, substantially pure carbon dioxide gas input at 40 sccm / cm2, and current density substantially maintained at 500 mA / cm2. The first gasket is 0.012 inches thick, resulting in an HCR of 1:4 and a voltage of 3.6 V. The second gasket is 0.010 inches thick, resulting in an HCR of 1:10.1 and a voltage of 3.8 V.

[0079] Characteristics of the flow field can additionally or alternatively be used to affect CCP and / or H2 production. In a first specific example of control based on flow field characteristics, reactor configuration A is used under two different sets of process conditions, both with reactor temperature substantially maintained at 30 °C and reactor pressure substantially maintained at 120 psi. In the first set of conditions, an interdigitated flow field is used, substantially pure carbon dioxide gas is input at 10 sccm / cm2, and current density is substantially maintained at 160 mA / cm2, resulting in a CO:H2 ratio of 1.6:1. In the second set of conditions, a quadruple serpentine flow field is used, substantially pure carbon dioxide gas is input at 40 sccm / cm2, and current density is substantially maintained at 120 mA / cm2, resulting in a CO:H2 ratio of 18.5: 1.

[0080] In a second specific example of control based on flow field characteristics, reactor configuration A is used under two different sets of process conditions, both with reactor temperature substantially maintained at 30 °C, reactor pressure substantially maintained at 100 psi, substantially pure carbon dioxide gas input at 40 sccm / cm2, and current density is substantially maintained at 500 mA / cm2. In the first set of conditions, an interdigitated flow field is used and a voltage of 3.6 V is substantially maintained, resulting in a CO:H2 ratio ofDocket No. OPUSP049WO1.6:1. In the second set of conditions, a triple serpentine flow field is used and a voltage of 3.8 V is substantially maintained, resulting in a C0:H2 ratio of 10.1:1.

[0081] However, any other suitable flow field can additionally or alternatively be employed to control the reactor outputs, the process conditions can additionally or alternatively include any other suitable reactor conditions, and the method can additionally or alternatively include controlling the reactor output in any suitable manner.5. Impurity tolerance

[0082] In some embodiments, such as embodiments in which the reactor is run at a high pressure and / or the catalyst is held at low voltage (e.g., negative voltage relative to the anode), the system and / or method may achieve high tolerance to impurities and / or dilute carbon dioxide inputs (e.g., as compared to other carbon dioxide reactors), such as tolerance to poisoning by impurities in the reactor input(s) and / or to inputs diluted by species such as methane, CO, O2, and / or N2. For example, the method can include determining target process conditions (e.g., reactor configuration such as PEM type, high target reactor pressure, etc.) to achieve impurity and / or dilute input tolerance (e.g., always selecting such process conditions; selecting such process conditions in response to a current and / or anticipated state of the reactor input, such as an impure and / or dilute state, etc.). These impurities can include species typically present in reactor input streams (e.g., products of coal and / or natural gas combustion, such as outputs from coal- or natural gas-fired power plants), such as SOXand / or NOX, and / or can include any other impurities such as ammonia, hydrogen sulfide, and mercury. In one example, the system and / or method are capable of functioning effectively using input streams including up to 4% CO, 6% O2, 10% N2, 800 ppm NOX, and / or 100 ppm SOX, with a sum of CO, O2, and N2 impurities, e.g., no greater than 10%.

[0083] In a specific example of dilute input tolerance, reactor configuration A with a single serpentine flow field is used, current density is substantially maintained at 160 mA / cm2, reactor pressure is substantially maintained at 110 psi, reactor temperature is substantially maintained at 20 °C, and carbon dioxide-containing gasses with various levels of dilution in methane or nitrogen are input at 200 sccm / cm2. In this specific example, reactor performance is highly tolerant of methane dilution up to at least 50% methane, wherein methane concentrations of 0%, 25%, and 50% result in CO:H2 ratios between 9.5:1 and 8.5:1 and CO fractional yields greater than 90%. More significant performance reduction is observed using 75% methane, with a reduction in CO fractional yield to approximately 84%. In this specific example, similar tolerance to nitrogen dilution is observed, wherein nitrogen concentrations of 0%, 25%, 50%, and 75% result in CO:H2 ratios between 9:1 and 8:1, and nitrogen concentrations up to 50%Docket No. OPUSP049WO result in CO fractional yields greater than 85% (with 75% nitrogen concentration resulting in a CO fractional yield of approximately 81%).

[0084] In a specific example of impurity tolerance, reactor configuration A with a single serpentine flow field is used, current density is substantially maintained at 150 mA / cm2, reactor pressure is substantially maintained at 100 psi, reactor temperature is substantially maintained between 20 °C and 25 °C, and carbon dioxide-containing gases with various impurities are input at 100 sccm / cm2. In this specific example, reactor output metrics (e.g., CO fractional yield) under the various impurity conditions are compared to baseline reactor performance under the same conditions but using a substantially impurity-free carbon dioxide input. In this specific example, reactor performance was shown not to deviate significantly from the baseline performance for CO concentrations of 4% or less, for NOXconcentrations of 800 ppm or less, for SOXconcentrations of 120 ppm or less, or for oxygen concentrations of 6% or less.

[0085] However, the system and / or method can additionally or alternatively exhibit any suitable tolerance to impure and / or dilute inputs or exhibit no such tolerance.

[0086] In certain embodiments, an impurity or multiple impurities pass through the carbon oxide reduction reactor to an output stream where they are (a) separated upstream of another chemical reactor, and / or (b) passed into another chemical reactor. In embodiments where impurities in an output stream are passed to another chemical reactor, impurities may be used by the other reactor in the chemical manipulation of that process. For example, hydrogen sulfide or other sulfur-containing impurities may be employed by microbial species in a downstream bioreactor.6. System configuration selection

[0087] One or more system configurations may be employed based on output HCR considerations, such as based on a desired output HCR (e.g., given a particular set of process conditions and / or a range of acceptable process conditions) and / or HCR range.

[0088] In some embodiments, this includes: at a first reactor (e.g., electrolyzer, such as a gasphase electrolyzer), accepting an input including a carbon oxide and electrochemically producing a first reduction product (e.g., including molecular hydrogen and / or one or more CCPs other than the carbon oxide input at a first HCR) from the input (e.g., under a first set of process conditions). The choice of the first reactor design and its operating conditions may include determining a desired HCR and / or HCR range (e.g., based on downstream reactor metrics, market price metrics, efficiency metrics, and / or any other suitable metrics) and selecting a system configuration (e.g., for a second reactor) based on the first HCR and / or the desired HCR (e.g., such that the second reactor will or can output a reduction product with anDocket No. OPUSP049WOHCR closer to the desired HCR relative to the first HCR, optionally substantially under the first set of process conditions but additionally or alternatively under any other suitable process conditions). For example, the configuration for the second reactor can be selected such that the second reactor would, under conditions substantially identical to those of the first reactor (e.g., while accepting the input under the first set of process conditions), produce a second reduction product from the input, wherein the second reduction product includes molecular hydrogen and the same CCSs as the first reduction product (e.g., includes substantially all species present in the first reduction product), wherein the second reduction product defines a second HCR substantially different from the first HCR, wherein the second HCR may be closer to the desired HCR than the first HCR. Substantial difference between the first HCR and second HCR, for this example and / or any other embodiment described herein, can include the second HCR: being closer to the desired HCR than the first HCR; differing from the first HCR (e.g., being greater or lesser than the first HCR) by at least 1%, 5%, 10%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 0.5-5%, 2-10%, 5-25%, 20-50%, 40-80%, and / or 75-100%; and / or otherwise differing from the first HCR.

[0089] In some embodiments, selecting system configurations can include selecting one or more aspects of a PEM, such as to alter the output HCR. Such selection can include selecting membrane compositions (e.g., different polymer species) and / or microstructures, selecting membrane layer thicknesses, and / or selecting any other suitable aspects of the PEM. In some examples, such selection includes selecting a thickness of an anion exchange membrane and / or proton exchange membrane (e.g., wherein a bipolar PEM with more AEM will tend to produce a lower output HCR than one with more proton exchange membrane). In a first specific example, selecting a thinner AEM (e.g., thinner than a reference AEM thickness such as a thickness of the first reactor AEM, thinner than an optimized AEM thickness substantially corresponding to optimal CCP production, etc.) can result in a reactor configured to produce a higher output HCR, whereas selecting a thicker AEM (e.g., thicker than the reference AEM thickness but optionally no thicker than the optimized AEM thickness) can result in a reactor configured to produce a lower output HCR.

[0090] Selecting system configurations can additionally or alternatively include selecting one or more aspects of reactor catalyst(s) (e.g., reduction catalyst, oxidation catalyst), such as to alter the output HCR. In some variations, selecting reactor catalyst aspects can include selecting a catalyst layer thickness (e.g., wherein a thicker reduction catalyst will tend to produce a higher HCR). In one example, selecting a thicker reduction catalyst layer (e.g., thicker than a reference reduction catalyst layer thickness such as a thickness of the first reactor reduction catalyst layer,Docket No. OPUSP049WO thicker than an optimized reduction catalyst layer thickness substantially corresponding to optimal CCP production, etc.) can result in a reactor configured to produce a higher output HCR, whereas selecting a thinner reduction catalyst layer (e.g., thinner than the reference reduction catalyst layer thickness but optionally no thinner than the optimized reduction catalyst layer thickness) can result in a reactor configured to produce a lower output HCR.

[0091] Selecting reactor catalyst aspects can additionally or alternatively include (e.g., in embodiments in which a catalyst layer includes catalyst particles, such as nanoparticles, defining a porous network) selecting a catalyst porosity (e.g., wherein a more porous reduction catalyst network will tend to produce a lower HCR). In one example, selecting a less porous reduction catalyst network (e.g., less porous than a reference reduction catalyst such as a porosity of the first reactor reduction catalyst network, less porous than an optimized reduction catalyst substantially corresponding to optimal CCP production, etc.) can result in a reactor configured to produce a higher output HCR, whereas selecting a more porous reduction catalyst (e.g., more porous than the reference reduction catalyst but optionally no more porous than the optimized reduction catalyst) can result in a reactor configured to produce a lower output HCR.

[0092] Selecting reactor catalyst aspects can additionally or alternatively include (e.g., in embodiments in which a catalyst layer includes catalyst particles, such as nanoparticles, and one or more polymer electrolytes, such as wherein the catalyst particles define a porous network that contains the polymer electrolyte and / or are mixed into a medium including the polymer electrolyte) selecting a catalyst-to-polymer electrolyte ratio (CPR) (e.g., wherein a higher reduction catalyst CPR will tend to produce a higher HCR), such as by selecting a degree of polymer electrolyte loading into a porous reduction catalyst network. In one example, selecting a higher reduction catalyst CPR (e.g., higher CPR than a reference reduction catalyst CPR such as a CPR of the first reactor reduction catalyst network, higher CPR than an optimized reduction catalyst substantially corresponding to optimal CCP production, etc.) can result in a reactor configured to produce a higher output HCR, whereas selecting a lower CPR reduction catalyst (e.g., lower CPR than the reference reduction catalyst but optionally no lower than the optimized reduction catalyst CPR) can result in a reactor configured to produce a lower output HCR.

[0093] Selecting reactor catalyst aspects can additionally or alternatively include (e.g., in embodiments in which a catalyst layer includes catalyst particles, such as nanoparticles) selecting a characteristic catalyst particle size (e.g., wherein a larger particle size will tend to produce a higher HCR). In one example, selecting a larger reduction catalyst particle size (e.g., larger than the particles of a reference reduction catalyst such as the first reactor reductionDocket No. OPUSP049WO catalyst, larger than an optimized reduction catalyst substantially corresponding to optimal CCP production, etc.) can result in a reactor configured to produce a higher output HCR, whereas selecting a smaller reduction catalyst particle size (e.g., smaller than the particles of the reference reduction catalyst but, e.g., no smaller than the particles of the optimized reduction catalyst) can result in a reactor configured to produce a lower output HCR. However, the method can additionally or alternatively include selecting any other suitable reactor catalyst aspects.

[0094] The method can additionally or alternatively include selecting a reactor cell compression (e.g., wherein lower compression will tend to result in higher HCR and higher compression will tend to result in lower HCR), a flow field, and / or any other suitable aspects of the system.

[0095] U.S. Provisional Application serial number 62 / 619,996, filed on 22-JAN-2018, U.S. Provisional Application serial number 62 / 620,109, filed on 22- JAN-2018, and U.S. Provisional Application serial number 62 / 685,771, filed on 15-JUN-2018, are each incorporated herein by reference in its entirety.

[0096] The electrolyzer design and operating conditions can be tuned for particular applications, and for producing a cathode output having specified compositions. In some implementations, one or more general principles may be applied to operate in a way that produces a required output stream composition.

[0097] 1. Restrict carbon dioxide reactant availability at the cathode active sites and / or increase current density at the cathode. These operating condition ranges tend to produce the following results: (a) initially, upon decreasing the carbon dioxide reactant availability and / or increasing the current density, the fraction of CO2 converted to CO increases (i.e., CO:CO2 in the output stream increases); (b) at some point, upon further decreasing the carbon dioxide reactant availability and / or increasing the current density, the hydrogen ion reduction reaction becomes more pronounced (i.e., H2:CO increases). Electrolyzers that can operate with relatively little carbon dioxide input / availability may have flow fields or gas diffusion components that restrict carbon dioxide from reaching active sites on the electrolyzer cathode. In certain embodiments, flow field designs that are not interdigitated, and such flow field designs that have long paths such as serpentine paths between the source of CO2 and the cathode result in higher ratios of CO:H2. Interdigitated flow field forces input gas (carbon oxide) to flow through the gas diffusion layer before exiting at a different location on the flow field. Non-interdigitated designs have long continuous paths for the carbon oxide feed gas to flow into and out of the cathode. Channels on the inlet side are spaced from the channels on the outlet side. In certainDocket No. OPUSP049WO embodiments, gas diffusion electrodes that are relatively thick restrict CO2 mass transport to the cathode active sites and therefore tend to increase the ratio of C0:C02 and / or H2:C0.

[0098] 2. Make hydrogen ions relatively more available at the cathode. Making hydrogen ions relatively more available at the cathode may produce a cathode product stream with a relatively high ratio of tkiCO. Electrolyzers configured in a way that provide a relatively hydrogen rich product may employ designs that (a) starve the cathode of carbon dioxide reactant (as described in 1), (b) permit a relatively high flux of hydrogen ions to be transported from the anode, where they are generated, to the cathode, and / or (c) operate at a relatively high cell temperature. Electrolyzers that can operate with a relatively high flux of hydrogen ions to the cathode may have MEAs with cation conducting polymers and / or mixed ion conducting polymers at the cathode. Alternatively or additionally, in MEAs including a cathode buffer layer, the layer is designed to be relatively thin and / or have a relatively high hydrogen ion transference number.

[0099] 3. Make hydrogen ions less available at the cathode. Making hydrogen ions relatively less at the cathode may produce a cathode product stream with relatively high ratios of CO:H2. Electrolyzers configured in a way that provides a relatively hydrogen poor product may employ designs that (a) provide the cathode with surplus carbon dioxide reactant for a given current density, (b) contain MEA designs that prevent hydrogen ions from reaching the cathode, and / or (c) operate at a relatively low cell temperature.High CO2 reduction product to CO2 ratio operating parameter regime

[0100] In certain embodiments, an electrolyzer is configured to produce, and when operating actually produces, an output stream having a CO:CO2 molar ratio of at least about 1:1 or at least about 1:2 or at least about 1:3. A high CO output stream may alternatively be characterized as having a CO concentration of at least about 25 mole %, or at least about 33 mole %, or at least about 50 mole %.

[0101] In certain embodiments, this high carbon monoxide output concentration is obtained by operating a carbon dioxide electrolyzer in a manner that produces any one of or any combination of the following operating conditions: a current density of at least about 300 mA / cm2, at the cathode, a CO2 stoichiometric flow rate (as described elsewhere herein) of at most about 4, or at most about 2.5, or at most about 1.5 a temperature of at most about 80 °C or at most about 65, a pressure range of about 75 to 400 psig, an anode water composition of about 0.1 to 50mM bicarbonate salt, and an anode water pH of at least about 1.Docket No. OPUSP049WO

[0102] In certain embodiments, the electrolyzer may be built to favor high CO:CO2 molar ratios or concentrations, as defined here, by using a carbon dioxide electrolyzer having any one of or any combination of the following properties: relatively small nanoparticle cathode catalysts (e.g., having largest dimensions of, on average, about 0.1-15nm), gold as the cathode catalyst material, a cathode catalyst layer thickness of about 5-20um, a cathode gas diffusion layer (GDL) with a microporous layer (MPL), a cathode GDL with PTFE present at about 1-20 wt%, or about 1-10 wt%, or about 1-5 wt%, a GDL that has a thickness of at least about 200umI bipolar MEA having an anion-exchange cathode buffer layer having a thickness of at least about 5um, and a cathode flow field having parallel and / or serpentine flow paths.High reduction product (H2+CO) to CO2 ratio operating parameter regime

[0103] In certain embodiments, an electrolyzer is configured to produce, and in operation actually produces, an output stream having a (H2+CO):CO2 molar ratio of at least about 2:1 or at least about 1:2 or at least about 1:3.

[0104] In certain embodiments, this high reduction product output concentration is obtained by operating a carbon dioxide electrolyzer in a manner that produces any one of or any combination of the following operating conditions: a current density of at least about 300 mA / cm2, a CO2 stoichiometric flow rate of at most about 4, or at most about 2.5, or at most about 1.5 a temperature of at most about 125°C, a pressure of at most about 800 psi, anode water composition of 0 to about 500mM bicarbonate salt, and an anode water pH of about 0-15.

[0105] In certain embodiments, the electrolyzer may be built to favor high (CO+H2):CO2 molar ratios or concentrations, as defined here, by using a carbon dioxide electrolyzer having any one of or any combination of the following properties: nanoparticle cathode catalysts (e.g., having a largest dimension, on average, of about 0.1-1000nm), a transition metal as a cathode catalyst material,Docket No. OPUSP049WO a cathode catalyst layer thickness of about 0.1-100um, a cathode gas diffusion layer with or without a microporous layer (MPL), a GDL with about 0-70wt% PTFE, a GDL that is about 10-1000 um thick, and a bipolar MEA having an anion-exchange cathode buffer layer that is about 0-100um thick.Hydrogen rich product stream operating parameter regime

[0106] In certain embodiments, a carbon dioxide electrolyzer is configured to produce, and when operating actually produces, an output stream having FEiCO in a molar ratio of at least about 1:1.

[0107] In certain embodiments, such hydrogen rich output concentration is obtained by operating a carbon dioxide electrolyzer in a manner that produces any one of or any combination of the following operating conditions: a current density of at least about 300 mA / cm2, a CO2 mass transfer stoichiometric flow rate to the cathode of up to about 2, a temperature of at least about 65°C or at least about 80 °C, a pressure range of about 75 to 500 psig, an anode water composition of pure water or at least about 50 mM bicarbonate salt, and an anode water pH of at most about 1.

[0108] In certain embodiments, the electrolyzer may be built to favor hydrogen rich molar ratios or concentrations, as defined here, by using a carbon dioxide electrolyzer having any one of or any combination of the following properties: relatively large nanoparticle cathode catalysts (e.g., having a largest dimension of, on average, at least about 80 nm) silver, palladium, or zinc as the cathode catalyst material, a cathode catalyst layer thickness of at most about 5 um or a thickness of at least about 25um, a cathode gas diffusion layer with no microporous layer (MPL), a cathode GDL with no PTEE present or at least about20wt% PTFE, a cathode GDL having a thickness that is at most about 200um or at least about 500um, and a bipolar MEA having an anion-exchange cathode buffer layer with a thickness that is about 0-5um.Docket No. OPUSP049WOHigh reduction product to hydrogen product stream operating parameter regime

[0109] In certain embodiments, a carbon dioxide electrolyzer is configured to produce, and when operating actually produces, an output stream having CO:H2 in a molar ratio of at least about 2:1.

[0110] In certain embodiments, such product rich output concentration is obtained by operating a carbon dioxide electrolyzer in a manner that produces any one of or any combination of the following operating conditions: a current density at the cathode of at least about 300 mA / cm2, a CO2 mass transfer stoichiometric flow rate to the cathode of at least about 1.5, or at least about 2.5, or at least about 4, a temperature of at most about 80 °C, a pressure in the range of about 75 to 400 psig, an anode water composition of about 0.1 mM to 50mM bicarbonate salt, and an anode water pH of greater than about 1.

[0111] In certain embodiments, the electrolyzer may be built to favor product-rich molar ratios or concentrations, as defined here, by using a carbon dioxide electrolyzer having any one of or any combination of the following properties: relatively small nanoparticle catalysts (e.g., having largest dimensions of, on average, about 0.1-15nm), gold as the cathode catalyst material, a cathode catalyst layer thickness of about 5-20um, a cathode gas diffusion layer with a microporous layer (MPL), a cathode GDL with PTFE present at about 1-20 wt%, or about 1-10 wt%, or about 1-5 wt%, a cathode GDL that has a thickness of at least about 200um, and a bipolar MEA having an anion-exchange layer with a thickness of at least about 5um.Stoichiometric flow rate

[0112] Given that a molar flow rate may be determined, at least in part, by the electrical current delivered to the cell, the molar flow rate may be tied to the current. As an example, the molar flow rate of carbon oxide in the input stream may be defined in terms of flow rate per unit of reaction expected for a given current. Herein, the term “stoichiometric” flow rate refers to a fraction or multiple of the flow rate of reactant carbon oxide required to fully utilize all current at the cathode, assuming that the reduction reaction of carbon oxide is 100% efficient at the cathode to a given reaction. A flow rate of carbon oxide having a stoichiometric value of “1”Docket No. OPUSP049WO is the flow rate required to consume all electrons provided at the cathode, and no more than that, in the given reduction reaction at the cathode. Stated another way, the stoichiometric flow rate is the amount of excess (or shortfall) reactant that is present beyond (or below) what could be theoretically reacted if the current efficiency for a given reaction were 100%.

[0113] For the carbon dioxide reduction reaction that produces carbon monoxide in an acidic environment (CO2 + 2H++ 2e-CO + H2O), a carbon dioxide flow rate with a stoichiometric value of 1 provides one mole of carbon dioxide for every two moles of electrons provided by the cell. Stated another way, a cell having a current providing 2 moles of electrons / second and a carbon dioxide flow rate providing 1 mole of carbon dioxide molecules / second would have a stoichiometric flow rate of 1. For the same current and a flow rate of 0.5 carbon dioxide moles / second, the cell would have a stoichiometric flow rate of 0.5. And, again for the same current but with a flow rate of 1.5 carbon dioxide moles / second, the cell would have a stoichiometric flow rate of 1.5. The molar flow rate needed to achieve a stoichiometric flow rate of 1 can be calculated:Stoichiometric Flow Rate (seem) = [60 (s / min) * Molar gas volume at STP (mL / mol)] / [Faraday’s constant (C / mol e-) * #e-‘s / mole CO2] * Amps of current fed to the electrolyzerTotal amps of current can be calculated from the current density, the area of the electrolyzer cell and the number of cells in the electrolyzer:Amps of current = current density * area of the electrolyzer cell * number of cells

[0114] In an example, a 100cm2electrolyzer with a current density of 500mA / cm2performing the electrochemical reduction of CO2 to CO has a total current of 50A and the reaction requires 2 moles of e- / mole CO produced, so the stoichiometric flow rate of 1 is:[60*22,413] / [9,6485 * 2] * 50 = 348.4 seemIn this example, a stoichiometric flow rate of 0.5 would be: 0.5 * 348.4 = 174.2 seemAnd a stoichiometric flow rate of 2 is:2 * 348.4 = 696.8 seem

[0115] In another example of a cell producing ethylene from carbon dioxide, 12 moles of electrons are needed to reduce 2 moles of carbon dioxide to 1 mole of ethylene. The stoichiometric flow rate for a 3 cell 1500cm2 electrolyzer with a current density of 300mA / cm2 is:[60*22,413] / [96,485 * 6] * 1350 = 3,136 seem.Docket No. OPUSP049WO

[0116] Various examples of the effects of certain electrolyzer design and operating parameters on the molar ratios of gases in a cathode output stream are presented in US Provisional Patent Application No. 63 / 263,567, filed November 4, 2021, which has been incorporated herein by reference in its entirety.

[0117] In various embodiments, oxygen produced at the anode of a carbon oxide electrolyzer is used in an integrated process. As examples, the electrolyzer-produced oxygen may be used in partial oxidation gasification processes, aerobic fermentation processes, electrolysis processes employing oxygen depolarization electrodes, etc. In one example of an integration scheme, a system having a Fischer-Tropsch reactor may employ a carbon dioxide electrolyzer configured to produce syngas as an input to the Fischer-Tropsch reactor and to produce oxygen as an input to reactor for gasification of biomass, which also produces syngas for input to the Fischer-Tropsch reactor.7. Integration Schemes

[0118] Additional information regarding optional embodiments and / or elements of the system and / or method are provided below.

[0119] A product gas from a carbon oxide reactor of the disclosure can be used in one or more downstream processes. For example, a carbon dioxide reactor of the disclosure configured for syngas production can output a stream of CO, H2, and / or CO2. Heat produced during operation of a carbon oxide electrolyzer may be used in one or more upstream and / or downstream processes that require heating.

[0120] Figure 3 depicts a system 501 including a carbon dioxide electrolyzer 503 configured to produce syngas. System 501 also includes an aerobic fermentation reactor 505 configured to produce syngas. System 501 is also configured to deliver oxygen produced at the anode of electrolyzer 503 to reactor 505. This oxygen may replace some of the oxygen normally provided from alternative sources such as air separation and therefore reducing the energy duty and scale of the air separation unit.

[0121] System 501 is configured to deliver the syngas produced by electrolyzer 503, the fermentation reactor 505, and potentially other sources to a downstream gasification unit or partial oxidation unit 507. System 501 may be configured to deliver some waste carbon dioxide from unit 507 to the cathode input stream of electrolyzer 503.Naphtha and Fuels

[0122] As indicated, Fischer-Tropsch reactions may be characterized by the following general expression:(2n+l)H2+ nCO -> CnH2n + nH2ODocket No. OPUSP049WO

[0123] While the following discussion focuses on Fischer-Tropsch (F-T) reactions, those of skill in the art appreciate that a class of related reactions may be employed to produce liquid hydrocarbons and mixtures thereof from input streams that include hydrogen and carbon monoxide. The class of reactions produces various compositions of liquid hydrocarbon mixtures, dependent on the composition of the input stream and the reaction conditions. While the term Fischer-Tropsch is used herein, it should be understood to cover any of a class of reactions that produce liquid hydrocarbons from a mixture including carbon monoxide and hydrogen. Generally, such reactions are exothermic.

[0124] In some embodiments, the naphtha comprises a mixture of hydrocarbons that may be produced as part of the output of a Fischer-Tropsch reaction or other reaction that produces liquid hydrocarbons from carbon monoxide, hydrogen, and optionally other inputs. In certain embodiments, at least 90 wt% (e.g., at least 92 wt%, at least 95 wt%, at least 97 wt%, at least 99 wt%, or all) of the hydrocarbons in naphtha have a size of about C4 to CIO (or about C4 to C9). In some embodiments, within naphtha, about 10 wt% to 40 wt%, about 15 wt% to 35 wt%, or about 20 wt% to 30 wt% of the hydrocarbons have a size of about C4 to C5. In some embodiments, within naphtha, about 50 wt% to 90 wt%, about 65 wt% to 85 wt%, or about 70 wt% to 80 wt% of the hydrocarbons have a size of about C6 to C9. In some embodiments, naphtha may be condensed at a temperature of about 35 °C to 50 °C, about 38 °C to 49 °C, or about 40 °C to 45 °C.

[0125] In various embodiments, the input stream to a Fischer-Tropsch reactor is about 1:2 molar ratio of CO:H2. To use CO2 as starting point for producing CO / H2 mixture (or other Fischer-Tropsch input), some conventional, non-electrolytic processes require two steps. For example, a conventional process employs a first process to produce CO2 + H2 (step 1) and then a reverse water gas shift (RWSG) reaction (step 2) to react CO2 + H2 and produce CO and water to result in a gas having a ratio close to the required 2:1 CO:H2. Thus, in a conventional process, only after obtaining the CO and hydrogen in the correct ratio can a Fischer-Tropsch reaction be employed to produce liquid hydrocarbons. Water shift (WSG) reaction and reverse water shift reaction catalysts can produce metal dust that is detrimental to downstream processes. Further, the water shift reactions require a feed of carbon monoxide and / or hydrogen.

[0126] Note that a conventional syngas process is sometimes used to directly produce CO + H2 mixture (rather than using a WSG and / or RWSG reaction or a carbon dioxide electrolyzer which may emphasize production of CO). However, syngas production often uses coal.Docket No. OPUSP049WO

[0127] A Fischer-Tropsch system that employs a carbon dioxide electrolyzer as a source of carbon monoxide has various advantages over the WSG or syngas routes. For example, unlike a RWSG reaction, a carbon dioxide electrolyzer does not produce metal dust. Additionally, in comparison to the RWGS reaction, a carbon dioxide electrolyzer provides a higher conversion of CO2to CO.

[0128] However, a carbon dioxide electrolyzer may not produce gas having the required approximately 1:2 molar ratio of CO:H2for a Fischer-Tropsch feed. In some cases, a carbon dioxide electrolyzer produces a CO-rich stream. Therefore, in some embodiments, a Fischer- Tropsch system, or any other system that requires a carbon monoxide and hydrogen mixture, may employ a water electrolyzer or other source of hydrogen that optionally works in conjunction with carbon dioxide electrolyzer. The water electrolyzer is configured to make gaseous hydrogen to supplement the CO-rich output of the carbon dioxide electrolyzer. In some embodiments, syngas that is relatively rich in hydrogen can be produced as part of coelectrolysis of carbon dioxide and water. To achieve an approximately 1:2 CO:H2feed concentration for a F-T reaction, the system may include sensors configured to determine the concentration of CO and H2coming through the gas separation unit from the CO2electrolyzer. Using the sensed information as feedback, the operating conditions of a water electrolyzer may be adjusted to deliver a hydrogen stream with the quantity of H2needed to bring the total stream to approximately 1:2 CO:H2concentration.

[0129] Alternatively, a single CO2electrolyzer can be used to produce a suitable Fischer- Tropsch CO and H2feed blend. This can be accomplished by operating the electrolyzer in a way that biases the output toward hydrogen production and / or by processing the electrolyzer output to adjust its composition prior to delivery to the Fischer-Tropsch reactor. In certain embodiments, a carbon dioxide electrolyzer includes an MEA that allows a relatively high proportion of H+ to reach the cathode. One way to promote a relatively high flux of H+ at the cathode is for a bipolar MEA to employ a relatively thin cathode buffer layer and / or to employ cathode and cathode buffer layers having polymers with a relatively high H+ transference number. In another approach, the carbon dioxide electrolyzer is constructed or operated in a way that starves it of carbon dioxide. In certain embodiments, the electrolyzer is operated at a relatively high current density, which tends to produce a higher ratio of hydrogen to carbon monoxide ratio. In some implementations, the electrolyzer employs both a relatively high current density and a relatively low carbon dioxide feed to the electrolyzer. Operating at a relatively high current density has the advantage of producing employing a relatively inexpensive electrolyzer for the cost of the equipment.Docket No. OPUSP049WO

[0130] The output of a CO2 electrolyzer contains product CO, byproduct H2, unreacted CO2, and water vapor. The system may be configured to remove the water vapor and separate the unreacted carbon dioxide. A gas separation unit may be used to separate the CO2 from the CO and H2 and / or otherwise concentrate the CO and H2. The system may include a recycle loop to recycle water to a water inlet of a CO2 or water electrolyzer. The unreacted and separated CO2 is then compressed and returned to the inlet of the CO2 electrolyzer. Examples of gas separation units are presented in Figures 5 and 6, and the associated description.

[0131] A F-T reactor may operate above about 300 psi and between about 150-300°C. If the output of a carbon dioxide electrolyzer and optional water electrolyzer is not at the required pressure, the system may employ a compressor to bring up the feed gas pressure before entering the F-T reactor. In the F-T reactor, the CO-H2 mixture is converted into raw F-T liquid and waxes. A system may include a separator following the F-T reactor to separate water, high melting point F-T liquid, medium melting point F-T liquid, and tail gas, a mixture of volatile hydrocarbons, CO2, CO, and H2. The F-T liquid may be further upgraded via hydrocracking. Distillation and separation of different fractions of the F-T liquid may result in jet fuel, diesel, and gasoline. Water from the F-T reactor can be filtered to remove impurities and fed to a water input of the CO2 and / or optional water electrolyzers.

[0132] A F-T system may be designed so that tail gas and / or volatile hydrocarbons (e.g. including methane) are recycled back to the CO2 electrolyzer. The system may be configured to separate the tail gas into CO2, which may be compressed and fed directly to the electrolyzer inlet and volatile hydrocarbons and unreacted CO and H2. The system may be designed or configured such that these products are fed to a combustion reactor to generate heat, energy, and CO2. The CO2 is then fed to the CO2 electrolyzer inlet. The O2 from the electrolyzer may be used as the oxygen source for combustion, resulting in a pure CO2 output stream. The combustion reactor may be run in “rich burn” mode utilizing an excess of fuel to oxygen to minimize the concentration of oxygen in the outlet stream. Water from the combustion reaction may be separated from the gas output and can be fed to the water input of the CO2 electrolyzer or water electrolyzer.

[0133] Because a Fischer-Tropsch reaction is exothermic, it produces heat that may be used for other purposes in a system. Examples of such other uses include separations (e.g., distillation of light hydrocarbons) and reactions. In conventional systems, such reactions are endothermic reactions for production of syngas such as reforming of fossil fuels, gasification of biomass, or production from carbon dioxide and hydrogen via reverse water gas shift. Hence, in conventional processing, all or a significant portion of the excess heat from a Fischer-Docket No. OPUSP049WOTropsch reaction is typically directed to the syngas production. In the present case, however, which produces syngas at a low temperature (e.g. less than about 100 °C) by processes such as carbon dioxide electrolysis optionally along with low temperature water electrolysis, there is more excess heat from the Fischer-Tropsch reaction available for other processes such as carbon dioxide capture, thereby reducing the overall external heat requirement of the system and improving carbon and energy efficiency of the carbon dioxide to fuel synthesis pathway.

[0134] In some embodiments, tail gas is fed to a reformer where methane or other gaseous hydrocarbon react with water to produce a mixture of hydrogen and carbon monoxide, a form of syngas. This may increase the yield of carbon from carbon dioxide in liquid hydrocarbon product. Depending on the composition of tail gas, the ratio of hydrogen to carbon monoxide may vary. In some embodiments, some amount of carbon dioxide and / or oxygen is present in reformer. In many cases, the reforming reaction is endothermic. In some embodiments, heat to drive the endothermic reaction is provided, at least in part, from excess heat generated during the Fischer-Tropsch reaction. In some embodiments, heat to drive the endothermic reaction is provided, at least in part, from excess heat generated during electrolysis of carbon dioxide by a carbon dioxide reduction electrolyzer. In some cases, some heat may be provided by combustion or direct electrical heat. For combustion-derived heat, oxygen (optionally from an electrolyzer) may be fed to the furnace to improve efficiency, and carbon dioxide emissions could be captured and fed to the electrolyzer.

[0135] Figure 4A depicts a system 601 configured to produce liquid hydrocarbons in which a primary or exclusive source of carbon is a carbon oxide feedstock such as one containing carbon dioxide and / or carbon monoxide. The system includes two primary reactors: an electrolytic carbon oxide reduction cell or electrolyzer 611 and a Fischer-Tropsch reactor 621.

[0136] The electrolyzer 611 is connected to a source of electricity and has one or more inlets for receiving reactants such as carbon dioxide and water. The electrolyzer 611 has one or more outlets on the anode side for removing oxygen and possibly trace impurities and one or more outlets on the cathode side for removing reduction products including at least carbon monoxide. Other compounds leaving the cathode side may include hydrogen, water, and carbon dioxide.

[0137] The cathode side outlet is connected to a purification unit such as a carbon monoxide purification unit 612 which is designed to separate or purify carbon monoxide from other components. In the depicted embodiment, purification unit 612 has one outlet for providing carbon monoxide and another outlet for providing carbon dioxide, hydrogen, and possibly some carbon monoxide. In certain embodiments, the carbon monoxide purification unit 612 may be a sorbent-based unit such as presented in Figures 5 and 6 and the associated description.Docket No. OPUSP049WO

[0138] In the system 601, carbon dioxide, possibly along with some hydrogen and carbon monoxide, are recycled from outlet of the CO purification unit 612 back to the inlet streams for the cathode side of electrolyzer 611.

[0139] The Fischer-Tropsch reactor 621 is configured to receive carbon monoxide and hydrogen in a pressurized feed stream and at a specified composition. In system 601, a compressor 624 compresses the carbon monoxide from the electrolyzer 611 along with hydrogen to an appropriate pressure for the Fischer-Tropsch reaction. A Fischer-Tropsch reaction may take place at a temperature of about 150-300 C and at a pressure of about one to several tens of atmospheres. The reaction is exothermic, so little or no heat is provided to the reactor 621.

[0140] As mentioned, the input to a Fischer-Tropsch reactor may have a CO:H ratio of about n:(2n+l), where n is the length in carbon atoms of the desired alkane product of the reaction. Thus, in various embodiments, the molar ratio of hydrogen to carbon monoxide provided to reactor 621 is about (2n+l) to n. To provide the desired inlet composition ratio of hydrogen to carbon monoxide for the Fischer-Tropsch reaction, a hydrogen source 614 may be coupled to the outlet of CO purification unit 612 or to the inlet of compressor 624. Alternatively, or in addition, the electrolyzer 611 may be designed or operated in a manner that produces a relatively high ratio of hydrogen to carbon dioxide. Reactor designs and operating conditions for accomplishing this ratio are described elsewhere herein. In some cases, a gas having a relatively high ratio of hydrogen to carbon monoxide is produced from reforming reaction, such as reaction using FT tail gas as an input.

[0141] As depicted, system is 601 is configured to provide the output of Fischer-Tropsch reactor 621 to a separator 623 configured to separate MFTL and HFTL Fischer-Tropsch liquids from water and tail gas. As depicted the Fischer-Tropsch water may be recycled back to the input of the CO purification unit 612 and / or the input of electrolyzer 611.

[0142] System 601 comprises a main recycle loop having a separation unit 631, a combustion chamber 632, and a water / gas separator 633. Separation unit 631 is configured to receive tail gas from separator 623 and remove carbon dioxide from volatile hydrocarbons. System 601 is configured to recycle carbon dioxide from unit 631 to a carbon dioxide feed stream to electrolyzer 611.

[0143] System 601 is configured to transport the various hydrocarbons from separation unit 631 to combustion unit 632, which is configured to bum the hydrocarbons using a source of oxygen from electrolyzer 611. In some cases, the hydrocarbons include naphtha, other liquid hydrocarbons, and / or methane, as described in more detail below. System 601 is configuredDocket No. OPUSP049WO to transport the combustion products from combustion unit 632 to gas / water separator unit 633, which is configured to separate carbon dioxide and water combustion products. System 601 is configured to transport the water to an anode inlet of electrolyzer 611 and transport the carbon dioxide to a cathode inlet of electrolyzer 611.

[0144] In certain embodiments, a carbon dioxide electrolyzer located upstream from a Fischer- Tropsch reactor is configured to operate in (a) a hydrogen rich product stream operating parameter regime as described herein, and / or (b) a high reduction product to CO2 ratio operating parameter regime as described herein.

[0145] In certain embodiments, system 601 comprises one or more carbon dioxide capture units containing a sorbent for capturing carbon dioxide during a first phase and releasing carbon dioxide during a second phase. Separation unit 631 and / or gas / water separator unit 633 may be configured to include or work in conjunction with such carbon dioxide capture unit. Examples Some principles of operation are provided in the description of direct air capture units described herein. In some embodiments, a Fischer-Tropsch system is configured to provide waste heat produced from an exothermic Fischer-Tropsch reaction to a carbon dioxide capture unit.

[0146] Figure 4B presents an example system 634 for producing a liquid hydrocarbon mixture from a carbon dioxide input stream 635 by using (a) a carbon dioxide electrolyzer 636 to produce carbon monoxide and hydrogen 637 and (b) a Fischer-Tropsch reactor 638 configured to receive carbon monoxide and hydrogen and produce liquid hydrocarbons. Carbon monoxide and hydrogen, at least some produced by electrolyzer 636 is preprocessed in syngas processing element 640 which may purify or otherwise modify the syngas (e.g., removal of unreacted CO2 from the electrolyzer as well as compression and / or heating or cooling of the syngas stream) prior to delivery prior to entering the Fischer-Tropsch reactor. Waste heat from electrolyzer 636 can be used in the purification or modification of syngas prior to entering the Fischer- Tropsch reactor. System 634 is further configured to provide processed gas from element 640 to Fischer-Tropsch reactor 638, which can produce a mixture light hydrocarbons and other components 642, which the system makes available to a product separation subsystem 643, which may include a feature for separating tail gas 641 from one or more liquid hydrocarbon streams 644. In the depicted embodiment, system 634 includes a reformer 645 and is configured to provide tail gas 641 to the reformer. The tail gas contains methane that can react with water (optionally also included in tail gas 641) by a methane reforming reaction to produce a hydrogen-rich mixture 647 of carbon monoxide and hydrogen. System 634 is also configured to deliver mixture 647 to syngas processing element 640, which prepares the gas forDocket No. OPUSP049WO introduction to the Fischer-Tropsch reactor 638. The methane reforming reaction is endothermic. In some embodiments, excess heat from the reaction in Fischer-Tropsch reactor 638 is provided to reformer 645. In some embodiments, excess heat from the reaction in electrolyzer 636 is provided to reformer 645.

[0147] In the embodiment depicted in Figure 4B, system 634 is optionally configured to provide oxygen 649 from electrolyzer 636 to a furnace 651, which is configured to burn fuel and produce additional heat for use with system 634 or elsewhere.Direct Air Capture of CO2

[0148] In certain embodiments, an electrolytic carbon dioxide reduction system uses carbon dioxide received directly from air. A system for such embodiments includes a direct air CO2 capture subsystem and a carbon dioxide reduction electrolyzer subsystem. The system is configured so that CO2 from the capture subsystem supplies CO2, directly or indirectly, to the cathode side of the electrolyzer subsystem.

[0149] Because air is often the only significant feedstock, an air capture CO2 electrolysis system may be deployed at any location where there is space for the system components. In some deployments, the system occupies a relatively unpopulated area. In some deployments, the system occupies a populated area. In some embodiments, the system is deployed, at least partially, on a vehicle or vessel. For example, an air capture unit may be provided on a vehicle or vessel while a carbon dioxide electrolyzer may be provided at a port or offshore platform. In some cases, the deployment location has a ready supply of energy, e.g., a location where solar and / or wind power is plentiful. In some cases, the deployment location is a desert. In some embodiments, the system is deployed in an extraterrestrial environment having a CO2- containing atmosphere. In some embodiments, the system is deployed on large vessel such as a cargo ship or military vessel such as an aircraft carrier. In some embodiments, the energy source is provided by a solar or windfarm associated with an offshore platform or port, while carbon dioxide capture unit is provided on a ship or other watercraft. A carbon dioxide electrolyzer may be provided on the offshore platform or port.

[0150] The system may be designed so that air or other gas is provided under specified conditions to the CO2 capture subsystem. In certain embodiments, fans, vacuum pumps, or simply wind are used to deliver air to a CO2 capture subsystem.

[0151] In certain embodiments, a carbon oxide is captured onboard a vessel or vehicle as fuel is combusted. The fuel may be used, for example, in an internal combustion engine to propel the vessel or vehicle. The fuel may be used for other purposes such as heating, electricity generation etc. The captured carbon oxide is provided to the cathode of a carbon oxideDocket No. OPUSP049WO electrolyzer, which produces a reduced product that is directly used, stored, or converted to a different product (e.g., a chemical, polymer, or fuel) by downstream processing. In embodiments, where the electrolyzer and associated downstream components are configured to produce fuel, the resulting fuel may be employed in the original vessel or vehicle, or in one or more other vessels or vehicles. In some implementations, both the carbon oxide capture subsystem and the electrolyzer, as well as an optional downstream processing subsystem, are provided on board, on the vehicle or vessel. In some implementations, only the carbon oxide capture subsystem is provided to the vehicle or vessel. In some cases, the captured carbon oxide is temporarily stored on the vehicle or vessel. For example, carbon dioxide may be stored in one or more tanks, pressurized containers, tanker ships, and the like. In other cases, the captured carbon oxide is stored off the vehicle or vessel such as in underground reservoirs, tanker ships, offshore platforms, and the like. In some cases, stored carbon oxide is offloaded from the vessel or vehicle where it is provided to a carbon oxide electrolyzer. Examples of locations where stored carbon oxide may be offloaded and / or where the electrolyzer is located include chemical plants, ports, and offshore platforms, including some located proximate a source of green energy such as a wind energy or solar energy. Examples of vessels and vehicles include ships, trucks, buses, passenger vehicles, aircraft, and other craft.

[0152] In certain embodiments, depending on the needs of the system, a carbon dioxide electrolyzer located downstream from a direct air CO2 capture subsystem is configured to operate in (a) a high reduction product to CO2 ratio operating parameter regime as described herein, (b) a hydrogen rich product stream operating parameter regime as described herein, or (c) a high reduction product to hydrogen product stream operating parameter regime as described herein.Purification Units

[0153] Various types of purification and / or separation units may be employed for purifying or otherwise concentrating carbon monoxide produced by a carbon dioxide electrolyzer. Examples include amine absorption units (used with, e.g., gas streams having about CO2 concentrations of about 20% by volume or lower), CO2 adsorption units that take advantage of CO2’s acidity, CO adsorption units (using, e.g., copper compounds), CO / CO2 separation compositions such as molecular sieves and metal organic frameworks, cryogenic system (e.g., flash distillation systems), and membrane permeation units. In certain embodiments, a CO purification unit is configured to operate at a pressure of about 100 to 400 psia. An amine- based CO2 absorption unit may employ an aqueous solution of an ethanol amine such as methyl diethanolamine MDEA, optionally with piperazine to enhance absorption kinetics. The amineDocket No. OPUSP049WO absorbent may be regenerated by application of heat. An example unit employs a water solution of about 30% (weight) MDEA and 1% (weight) piperazine.

[0154] Cryogenic systems work by cooling the gas mixture and then passing through a fractionation column to separate gases by boiling point. Multiple fractionation columns may be used in a single process to separate and deliver purified components of gas mixtures.

[0155] A membrane purification process uses membranes that retain the desired product gas but are highly permeable to the impurities in the gas stream. Membranes are packaged into modules where a high-pressure gas mixture is input at the inlet. The membrane retains the desired product gas at high pressure and allows the undesired impurity gases to leave in a separate low-pressure stream. For CO purification, the membrane retains CO, but allows H2 and CO2 to pass through. Pure CO will exit in the product stream. H2, CO2, and a small volume of CO will leave in the waste stream. The low-pressure waste stream can be repressurized by a compressor and passed through another membrane stage to increase the recovery of CO product. Greater than 99% pure CO can result from a membrane-based separation process.

[0156] A sorption process for removing CO may be employed. Sorption processes may employ pressure swing, temperature swing, vacuum swing, or changes in other operating conditions (e.g., humidity swing). Sorbents are typically solids or liquids with a high affinity for the desired gas molecule under one operating condition extreme and a low affinity for the gas molecule under the other extreme of operating condition. For example, sorbents for CO under high pressure conditions (e.g., about 300 kPa, and about 40-60C) can capture CO (about 60-70mol%) from a mixture of CO2 and H2. A system with 4 adsorption towers containing 8L each of sorbent results in a flow rate of about 5-10 Nm3 of 99-99.9% pure product CO. Use of larger towers or additional stages allows for about 20-30% CO-containing gas mixtures to be upgraded to about 99% or greater purity. Sorbents for CO adsorption have been developed by Kobe steel using copper dopants in a solid matrix such as carbon, alumina, or silica.

[0157] Figure 5 depicts a system 1901 for purifying a carbon monoxide stream containing carbon dioxide and possibly other components such as hydrogen. As depicted, system 1901 includes an absorber 1903 configured to selectively remove carbon dioxide by contacting the carbon dioxide containing gas with absorbent material such as an ethanolamine. Absorber 1903 includes a gas inlet 1905 for receiving an inlet gas stream such as a gas stream from a carbon dioxide electrolyzer (not shown). Absorber 1903 also includes a gas outlet 1907 for releasing purified carbon monoxide.Docket No. OPUSP049WO

[0158] Also, as depicted, absorber 1903 includes an inlet 1911 for receiving purified sorbent and an outlet 1909 for expelling loaded sorbent, e.g., sorbent containing higher concentrations of carbon dioxide than the sorbent entering the absorber 1903.

[0159] System 1901 also includes a regenerator 1913 configured to remove carbon dioxide expelled by absorber 1903 and thereby produce a regenerated sorbent material for reuse in the absorber 1903. In the depicted embodiment, the sorbent is regenerated by heating, which releases carbon dioxide. Heating occurs using a pre-heater 1915, and a reboiler 1917. In some embodiments, reboiler 1917 is configured to receive waste heat from the carbon dioxide electrolyzer (not shown). Preheater 1915 is configured to receive loaded sorbent from the outlet 1909 of absorber 1903 and deliver the preheated sorbent to an inlet 1919 of regenerator 1913. Preheater 1915 receives some heat from lean sorbent on its way to absorber 1903 from regenerator 1913.

[0160] System 1901 is configured to transport lean sorbent from an outlet 1923 of regenerator 1913, using a lean solvent pump 1921, to preheater 1915, where the sorbent loses some of its heat. System 1901 is also configured to transport lean sorbent from preheater 1915 to absorber inlet 1911 via a trim cooler 1925. Trim cooler 1925 is configured to further cool the sorbent to a temperature where it can effectively do its job of removing CO2 in absorber 1903. The trim cooler may be a water-cooled module.

[0161] As indicated, reboiler 1917 is configured to provide heat for regenerator 1913 to release carbon dioxide from loaded sorbent. As illustrated, reboiler 1917 is included in a recirculation loop that receives a fraction of the lean sorbent from regenerator outlet 1923 and returns heated lean sorbent to regenerator 1913 via an inlet 1927.

[0162] Additionally, system 1901 includes a recycle compressor 1931 configured to compress the carbon dioxide to, e.g., a pressure suitable for entering the carbon dioxide electrolyzer that produces the inlet carbon monoxide-containing stream.

[0163] System 1901 also includes a subsystem associated with regenerator 1913 that employs a condenser 1933 to condense some of the sorbent that may be included in the released carbon dioxide that exits regenerator 1913 through a gas outlet 1935. Note that condenser 1933 is configured to condense the sorbent and deliver it back to regenerator 1913 at a sorbent inlet 1937.

[0164] In some cases, a CO purifier is a hybrid system having two different purification subsystems connected in series. For example, a CO purifier may have a cryogenic subsystem upstream from sorbent subsystem. Hybrid systems may be used, for example, in systems whereDocket No. OPUSP049WO the input CO stream has a relatively low concentration carbon monoxide such as below about 70% molar.

[0165] Figure 6 illustrates a hybrid carbon monoxide purification system 2001 having a cryogenic preprocessing subsystem 2003 and a sorbent postprocessing subsystem 2005. The first phase of the system 2001 is the cryogenic subsystem 2003, which is configured to partially concentrate the carbon monoxide. In certain embodiments, the cryogenic subsystem is configured to concentrate carbon monoxide to a level of at least about 70% by volume.

[0166] As depicted, cryogenic preprocessing subsystem 2003 is configured to feed product gas from, e.g., a carbon dioxide electrolyzer (not shown) to a compressor 2007 which is configured to compress the gas to a defined pressure or density. System 2001 is configured to transport the compressed gas from compressor 2007 to a chiller 2011 configured to reduce the temperature of the compressed gas. Chiller 2011 is coupled to a refrigeration system 2009, configured to remove sufficient heat from Chiller 2011 to maintain the compressed gas at or below a desired temperature.

[0167] Chiller 2011 is configured to chill the compressed gas to a reduced temperature. Chiller 2011 is also configured to receive a CO2 slurry (which provides a reduced temperature) from a separator 2019 and release the CO2 to a trim vaporizer 2013 configured to release vaporized carbon dioxide. The vaporized carbon dioxide from trim vaporizer 2013 may be transported by system 2001 to a recycle compressor 2015, configured to provide pressurized carbon dioxide suitable for feed to the cathode side of the carbon dioxide electrolyzer.

[0168] In the depicted embodiment, cryogenic subsystem 2003 is configured to provide chilled and compressed from an output of chiller 2011 to a Joule Thompson valve 2017 configured to rapidly expand the compressed gas and thereby further cool the gas. This action may sufficiently cool the gas to convert some of the gaseous CO2 into liquid or solid or slurry. Regardless, the cold gas is provided to separator 2019 connected to the Joule Thompson valve 2017 and having a carbon dioxide slurry outlet 2021 and a partially purified carbon monoxide gas stream outlet 2023. In certain embodiments, the partially purified carbon monoxide stream has a concentration of at least about 50% molar or at least about 70% molar.

[0169] In the depicted embodiment, system 2001 is configured to provide the partially purified carbon monoxide gas stream from outlet 2023 to the sorbent postprocessing subsystem 2005, which in the depicted embodiment is configured similarly to the entire sorbent system 1901. As depicted, subsystem 2005 has an absorber 2033 configured to absorb carbon dioxide from the partially purified CO stream and output purified CO gas. Subsystem 2005 also has sorbent regenerator 2043. Other components of subsystem 2005 include a sorbent trim cooler, aDocket No. OPUSP049WO sorbent preheater, a lean sorbent pump, a sorbent reboiler, and a sorbent condenser. In some embodiments, the reboiler is configured to receive waste heat from the carbon dioxide electrolyzer (not shown).

[0170] While the discussion of Figures 5 and 6, as well as the other discussion of carbon monoxide purifiers describes cases that involve removal of carbon dioxide, carbon monoxide purifiers may additionally or alternatively be configured to remove other impurity gases such as sulfur containing gases (e.g., sulfur oxides).Supplemental Hydrogen Sources

[0171] In certain embodiments, an integrated system employing a carbon oxide electrolyzer includes an additional source of hydrogen (beyond that generated from the electrolyzer) or are configured to receive additional hydrogen from an external source. Examples of integrated systems that may employ additional sources of hydrogen include Fischer-Tropsch systems, polycarbonate production systems, ethylene glycol production systems, polyethylene terephthalate production systems, methanol, butanol, and / or other alcohol production systems, acetic acid production systems, isocyanate production systems, polyurethane production systems, and oxalic production systems. In certain embodiments, the additional source of hydrogen is a water electrolyzer such as a proton exchange membrane water electrolyzer. In some implementations, a water electrolyzer shares electrical infrastructure with a carbon oxide reduction electrolyzer. In certain embodiments, the additional source of hydrogen is a tank, canister, or other storage vessel external to the integrated system. In certain embodiments, the additional source of hydrogen is or comprises units configured to perform (a) steam reforming, thermal cracking, and / or partial oxidation of methane, fuel oil, petroleum coke, and / or other fossil fuels, coal gasification, (b) steam methane reforming, (c) gasification, pyrolysis, and / or other high temperature conversions of biomass, municipal solid waste, and / or other waste sources, (d) pressure swing adsorption of refinery waste streams, (e) separation of hydrogen byproduct from industrial reactions such as molten salt chlorine production, and / or (f) dissociation of water by, e.g., solar / thermal energy. In certain embodiments, methane or other simple hydrocarbons used in one or more of these units is derived from biogas.Recovery of Carbon Dioxide from Electrolyzer Output

[0172] In many implementations, the product gas exiting the cathode of a carbon dioxide electrolyzer includes a significant fraction of unreacted carbon dioxide. For example, the product gas may contain between about 10% and about 70% molar carbon dioxide. In certain embodiments, a system includes carbon dioxide recovery unit arranged to receive product gas from a carbon dioxide electrolyzer and produce a concentrated carbon dioxide product, whichDocket No. OPUSP049WO may optionally be recycled to the electrolyzer. In one example, carbon dioxide recovery unit comprises a direct air carbon dioxide recovery module such as described elsewhere herein. It should be understood that the product gas from a carbon dioxide electrolyzer may contain a much higher concentration of carbon dioxide than air. Therefore, a direct air capture unit used with an electrolyzer may have a modified configuration compared to a corresponding unit used for direct air capture. As examples, the direct air capture unit may employ temperature swing absorption, pressure swing absorption, or electro-swing absorption.Integration with the electrical grid

[0173] When the source of electrical energy for a grid is not directly controllable in response to demand, various problems may arise. Solar, wind, and certain other non-combustion-based sources of electrical energy are examples of sources where the energy generation is decoupled from energy demand.

[0174] When a renewable energy source is connected to an electrical grid, fluctuations in wind speed or sunlight intensity may lower the amount of power available on the grid to a point where the demand exceeds supply. This may lower the frequency of the grid, which can damage some electrical equipment and / or cause a brown out or black out.

[0175] To prevent this, a flexible power generator and consumer may be used in conjunction with a renewable power source. Such component may facilitate electrical grid load leveling system and be configured to draw a flexible load from the grid, reducing power demand when necessary to prevent demand from approaching the supply. This can provide frequency stabilization to the grid to allow it to operate with high amounts of renewable electricity.

[0176] Various approaches have been proposed to store the excess energy generated when supply outstrips demand. Examples include water reservoirs, batteries, and water electrolyzers. Using batteries, as an example, to store excess energy on a grid requires a large number of high-capacity batteries to provide sufficient capacity to store the maximum excess energy that energy sources on the grid may produce.

[0177] By comparison, a carbon oxide electrolyzer may store excess energy in the form of a liquid or a gas, which is relatively easy to store. And, compared to water electrolyzers, a carbon oxide reduction cell can be operated in a manner that produces liquid products rather than gaseous products. Liquid products may be easier to store, particularly given their relatively higher density.

[0178] The products of a carbon oxide electrolyzer can be used as fuel for generating electrical energy to put on the grid in periods where demand may exceed supply. The electrolyzer products may be combusted in a turbine or other mechanical source of electrical power and / orDocket No. OPUSP049WO electrochemically consumed in a fuel cell to directly produce electrical power. In certain embodiments, a carbon oxide electrolyzer output such as carbon monoxide or methanol is stored for later use in a fuel cell to directly inject electrical energy back into the grid. In certain embodiments, the fuel cell is a fuel cell configured to oxidize carbon-containing reactants (e.g., natural gas) such as a solid oxide fuel cell from Bloom Energy of Sunnyvale, CA.

[0179] CO2 electrolysis products can be gas (e.g., CO, methane, ethylene) or liquid phase (e.g., ethanol, methanol, ethylene glycol). Liquid products have the advantage of being easy to store for extended periods of time. Gas phase products can be converted to liquid-phase chemical compounds through a range of downstream processes, such as gas fermentation or thermochemical reactions. Gas and liquid phase products can also be used to make solid materials. For example, CO is one of the inputs needed to make polycarbonate or can react with potassium hydroxide to make potassium formate.

[0180] In these examples and throughout the disclosure, the described systems may be provided in a facility, a plant, or a complex of buildings. In some embodiments, all or many reactors and units and / or modules of a system are provided in a common factory, plant, or complex. For example, a system for producing a particular material such as a polycarbonate polymer or transportation fuel may comprise a carbon oxide electrolyzer and one or more other reactors that utilize a product of the electrolyzer and / or provide a reactant to the electrolyzer, and the electrolyzer and other reactors are provided in a single building or plant. In some cases, one or more system components is provided in the exterior environment. For example, a direct air capture unit may be provided outside, while a carbon dioxide electrolyzer is located inside a building, even though the system is configured to provide carbon dioxide from the direct air capture unit to the electrolyzer.Syngas Preparation

[0181] Embodiments described in this section pertain to making mixtures of carbon monoxide and hydrogen. Some of these mixtures may be referred to as syngas. The embodiments described here concern methods and systems configured to receive a mixture of carbon monoxide, carbon dioxide, and hydrogen and modify the mixture to produce a mixture of carbon monoxide and hydrogen having a particular composition. In some cases, the input is a gaseous mixture obtained from a carbon oxide electrolyzer such as one of the carbon oxide electrolyzers described herein.

[0182] A carbon monoxide and hydrogen mixture produced as described here may have various applications. For example, it can be used to produce liquid hydrocarbon composition such as may be produced by a Fischer-Tropsch process as described herein.Docket No. OPUSP049WO

[0183] Various embodiments for producing a mixture of carbon monoxide and hydrogen may employ carbon oxide separator system such as described herein.

[0184] A mixture of carbon monoxide and hydrogen may be produced by directly removing either CO or CO2 from an input stream. In embodiments that produce the mixture by directly separating CO from the input stream, hydrogen may be added to a purified CO stream downstream from a CO purification operation. For example, purified hydrogen may be prepared by separating it from CO2 in an operation that is downstream from the CO separation operation.

[0185] In some embodiments, a process of making a mixture of hydrogen and carbon monoxide may be characterized by the following operations:1. Separation of CO from the mixture by, e.g., ionic liquid absorption in a pressure swing absorption process2. Separate H2 from CO2 via, e.g., a membrane3. Mix H2 and CO

[0186] In certain embodiments for producing purified carbon monoxide directly from the input stream, an ionic liquid is used to strip the carbon monoxide from an input gas stream. During the separation, the ionic liquid contacts the input gas and selectively absorbs the carbon monoxide while allowing most of the hydrogen and carbon dioxide to pass (undissolved or unabsorbed). In some embodiments, the input stream contacts ionic liquid in an absorption column. After contacting, the input stream, a carbon monoxide rich stream of ionic liquid is fed to a stripper which operates under conditions that strip carbon monoxide from the ionic liquid. A resulting lean stream of ionic liquid may be recycled back to the component(s) that selectively absorb carbon monoxide.

[0187] In some implementations, a system configured to produce a mixture of carbon monoxide and hydrogen contains no components configured to cool an input or outstream below about 30° C or below about 20° C or below about 10° C. For example, the system does not include a compressor to chill the inlet gas below about 20° COxygen Production

[0188] A carbon oxide electrolyzer anode may produce oxygen from water. The oxygen may be employed in any of various integration schemes for the electrolyzer. In some cases, oxygen can be used in a combustion reaction with a fuel. In some cases, oxygen can be compressed and stored for later use. In certain embodiments, compressed oxygen is cooled and then passed through a throttle valve causing the oxygen to liquify. Cooling may be accomplished using a Freon-type cooler. In some cases, an oxygen stream is first cooled using a brine cooler (e.g.,Docket No. OPUSP049WO employing CaCh brine). For example, at 40 bars and -120 C, oxygen becomes liquid. In some implementations, the oxygen stream is cooled to about -70C or lower.Heat Produced by a Carbon Oxide Electrolyzer and Other Units

[0189] During normal operation, a carbon dioxide electrolyzer may generate heat. This is at least partially due to overpotential in carbon dioxide reduction reaction. This excess heat may be used in a desorption unit. In some cases, about 25 to 50% of the power supplied to a carbon oxide electrolyzer is converted to heat. Some or all the generated heat may be used in one or more downstream or upstream processes. In some embodiments, a carbon dioxide electrolyzer generates a gas and / or liquid stream containing heat energy. In some cases, the gas and / or liquid stream has a temperature of about 25-90C. In certain implementations, a carbon oxide electrolyzer generates a cathode output gas stream containing heat that may be supplied, by an integrated system, to one or more upstream or downstream units or subsystems. In some implementations, a carbon oxide electrolyzer generates an anode liquid output stream containing heat that may be supplied, by an integrated system, to one or more upstream or downstream units or subsystems. In some cases, a carbon oxide electrolyzer contains a dedicated heat transfer element such as a jacket and / or conduit(s) that, during operation, have coolant circulating. In some implementations, one or more bipolar plates of the electrolyzer are configured to have such coolant circulate through them. Heat transferred from the electrolyzer to the coolant may be supplied to other units or subsystems in an integrated system.

[0190] In some embodiments, heat generated by an electrolyzer is used to pre-heat an inlet stream to a subsystem such as a boiler. In some embodiments, heat generated by an electrolyzer is used in a heat swing process such as a direct process for capturing carbon dioxide, a carbon dioxide stripping process, and / or a carbon monoxide stripping process. In the integration embodiments described herein, any upstream or downstream unit operation that can utilize heat of the type produced by a carbon oxide electrolyzer in the integration embodiment may be configured to receive heat from the electrolyzer. Examples include driers, separators, and reactors, including those for making polymers or bulk chemicals such as any of those disclosed herein. Thus, during normal operation a system may deliver heat generated by a carbon oxide electrolyzer to one or more separate subsystems that make use of such heat to facilitate their operation.

[0191] As explained above, some integrated system embodiments employ a direct air capture (DAC) subsystem and a carbon oxide electrolyzer configured to deliver excess heat from the electrolyzer to the direct air capture subsystem. In temperature swing implementations, a CO2 capture unit (e.g., a DAC unit) requires heat energy to capture and release significant quantitiesDocket No. OPUSP049WO of carbon dioxide. As an example, a DAC unit may require at least about 1200kWh (4.32 GJ) of heat energy per ton of captured CO2. Further, with temperature swing, a DAC unit may desorb CO2 at elevated temperatures, which may be as low as about 70C.

[0192] Generally, any output of a CO2 electrolyzer can be used to supply heat to a DAC unit. Examples of such outputs include anode water and the gas output from the cathode side of the electrolyzer. As an example, some CO2 electrolyzers operate in a temperature range from about 20°C to about 110°C, and the anode water and / or the gas product stream may leave the electrolyzer at a temperature within this range.

[0193] In certain embodiments, the anode water leaving the electrolyzer is used to heat a component of a DAC unit. In certain embodiments, heat carried by anode water may contribute up to about 40% of the heat duty required by a DAC unit. Of course, the fractional contribution depends on various factors including the electrolyzer's operating temperature and electrolysis energy efficiency.

[0194] In some embodiments, the gas stream leaving the electrolyzer may contribute up to about 5% of the heat required by a DAC unit, again depending on the electrolyzer's operating temperature and electrolysis energy efficiency.

[0195] A temperature swing DAC unit may include a sorbent packed bed that, during operation, is held at a relatively low temperature such as ambient temperature when absorbing carbon dioxide and is elevated to a higher temperature when desorbing carbon dioxide. During desorption, the packed bed may be heated using an electrical heater, steam, or some other heating agent. In DAC embodiments described in this section, one or more heat exchangers may be employed to provide heat to the packed bed. In some embodiments, at least one such heat exchanger receives heat from an electrolyzer and / or from a reactor for an exothermic reaction. The positioning of such heat exchanger(s) depends on various design considerations. Notably, a DAC unit may have additional inlet and outlet pipes to accommodate streams produced by electrolyzers and / or other reactors. However, the DAC unit itself (packed bed, blowers, enclosed space, etc.) may remain unmodified.Shared CO2 Desorption Units

[0196] In certain embodiments, an integrated system includes a temperature swing CO2 capture system, a CO2 electrolyzer, and optionally one or more other units that generate heat via, e.g., an exothermic chemical reaction. Heat generated by the CO2 electrolyzer and / or other unit of the integrated system is provided to the CO2 capture system to facilitate release of purified CO2, which is provided as an inlet to the cathode of a CO2 electrolyzer.Docket No. OPUSP049WO

[0197] A temperature swing CO2 capture system may have absorption and desorption units. The absorption unit is configured to selectively remove CO2 from an impure CO2 gas stream. To accomplish this, the absorption unit may employ liquid sorbents such as amines (e.g., aqueous monoethanolamine (MEA)), polymer microcapsules composed of liquid carbonate cores and highly permeable silicone shells, etc. The desorption unit is configured to release CO2 from the sorbent by applying heat to the sorbent.

[0198] In some implementations, a CO2 capture system purifies at least two separate input streams of impure CO2. In some embodiments, a first stream is a CO2 feedstock for the CO2 electrolyzer of the integrated system. Examples of CO2 feedstocks include air, flue gas, etc. CO2 in the feedstock may be purified by removing other components such nitrogen before introduction to the cathode of the CO2 electrolyzer.

[0199] In some embodiments, a second stream of impure CO2 is provided from the CO2 electrolyzer’s cathode outlet stream, which contains a carbon-containing reaction product along with unreacted CO2. As an example, a CO2 electrolyzer may be 30% efficient in its conversion of CO2 to CO. The unreacted CO2 can be separated from the outlet stream by a CO2 capture system and then recycled to the cathode inlet of the CO2 electrolyzer. If the carbon-containing reduction product is CO, the outlet streams from a CO2 capture unit are purified CO and purified CO2.

[0200] In some embodiments, one of the streams of impure CO2 is a gas stream to be used by a reactor other than the CO2 electrolyzer. By removing CO2 from such a gas stream, the CO2 capture system not only produces a purified CO2 stream for input to the CO2 electrolyzer but also produces a purified reactant gas stream for the reactor. For example, the gas stream may contain hydrogen, CO, or mixture thereof (e.g., syngas) in addition to the CO2. Such a gas stream may be produced by a hydrocarbon reforming operation such as methane steam reforming or autothermal reforming. Alternatively, such a gas stream may be produced by water gas shift or reverse water gas shift reaction.

[0201] In some embodiments, the integrated system employs two or more absorption units for a temperature swing CO2 capture system and a single CO2 desorption unit shared by the two or more absorption units. In some implementations, a first absorption unit absorbs CO2 from a first source (e.g., a feedstock inlet stream such as air or flue gas), while a second absorption unit absorbs CO2 from a second source (e.g., an outlet stream of CO2 electrolyzer cathode). The desorption unit receives absorbent from both the first and second absorption units and desorbs CO2 from both sources. In some embodiments, the desorption unit mixes the absorbents from the two absorption units, while in other embodiments, the desorption unitDocket No. OPUSP049WO keeps the absorbents unmixed. Whether the system mixes the absorbents depends on factors such as the required loadings of the absorbents, the compositions of the absorbents (e.g., whether they use different amines), and the like.

[0202] To drive the desorption reaction, the desorption unit may utilize waste heat from the CO2 electrolyzer and / or one of the other heat-producing units in the integrated system. Examples of other heat-producing units include a water electrolyzer, a Fischer-Tropsch reactor, a methanol synthesis reactor, a methane or light hydrocarbon reformer such as an autothermal reformer, etc.

[0203] In some implementations, a vacuum may be applied to the desorption unit. Such implementations may be appropriate when the heat supplied from a unit operating at a relatively low temperature, e.g., below about 110°C. A CO2 electrolyzer sometimes operates in the range of about 65 to 90°C. Heat from an electrolyzer operating in this range may, in some implementations, be insufficient to desorb CO2 without application of a vacuum.Tail Gas Mediated CO2 Separation

[0204] In certain embodiments, an integrated system employs a liquid hydrocarbon synthesis reactor (e.g., a Fischer-Tropsch reactor), a pressure-mediated CO2 purification unit, and a CO2 electrolyzer. In some cases, a sweep gas produced by the liquid hydrocarbon synthesis reactor is used to facilitate release or separation of CO2 from the CO2 purification unit. As an example, the sweep gas may be a tail gas or related product from the reactor.

[0205] The general reaction of a Fischer-Tropsch reactor may be represented as:2H2+ CO H2O + -(CH2)- where the -(CH2)- is a mixture of liquid hydrocarbons.

[0206] This reaction produces some tail gas as a byproduct. The tail gas may include “light ends” such as methane, ethane, carbon dioxide, unreacted CO, unreacted H2, etc. Regardless of composition, the sweep gas may be employed to drive desorption or separation of CO2 during a CO / CO2 separation and / or a direct air capture of CO2. Purified CO2 from the CO2 separation unit may be provided to a cathode inlet of the CO2 electrolyzer.

[0207] In some embodiments, tail gas is used solely as the sweep gas. In some embodiments, tail gas is mixed with another component such as CO or other target gas produced by the CO2 electrolyzer. In some embodiments, the purification system employs some CO to first clean a pressure mediated module prior to switching to tail gas. In some cases, using tail gas alone can inhibit or poison a pressure-mediated separation unit, hence it can be useful to mix it with another gas for first expose the purification system membrane or other component with a gas that does not comprise tail gas (e.g., CO).Docket No. OPUSP049WO

[0208] In some implementations, the CO2 purification unit employs a membrane-based pressure swing CO2 capture unit. In such implementations, the unit employs a membrane that selectively passes or blocks CO2 when exposed to different CO2 partial pressures on opposite sides of the membrane. Tail gas may provide the pressure difference needed to drive this process.

[0209] In other implementations, the CO2 purification unit employs a sorbent-based pressure swing CO2 capture unit. The absorbent selectively absorbs CO2 at low pressure and releases CO2 when exposed to a sweep gas. Examples of solid sorbents include porous carbonaceous materials, zeolites, alumina, silica, and metal-organic frameworks (MOFs). A tail gas may be employed to provide a high pressure needed for CO2 desorption.

[0210] After the tail gas serves its purpose as a sweep gas for CO2 purification, it can be employed for another purpose in an integrated system. In one example, the tail gas is combusted to produce heat that can be used by a different reaction in the integrated system. In another example, the tail gas is used in a methane steam reforming reaction, an autothermal reforming reaction, etc. In still another example, CO2 produced by purifying the tail gas (optionally with the pressure-mediated CO2 purification unit) is employed as an input to the cathode of the CO2 electrolyzer.

[0211] In certain embodiments, tail gas used in the integrated system includes one or more light hydrocarbons (e.g., methane, ethane, and / or ethylene), unreacted hydrogen, unreacted carbon monoxide, carbon dioxide, or any combination thereof.Shared Infrastructure for CO2 Electrolysis and CO2 Separation

[0212] Certain aspects of this disclosure pertain to integrated systems having a carbon dioxide electrolyzer and a carbon dioxide separation unit such as a direct air capture (DAC) unit that share infrastructure such as a fan, a cooling tower, and the like. Some such integrated systems may additionally include a liquid hydrocarbon synthesis reactor that optionally shares infrastructure with the carbon dioxide electrolyzer and / or the DAC.

[0213] As an example, an integrated system may employ a fan for (a) cooling the electrolyzer and (b) drawing in air or other impure CO2 stream to a direct air capture unit. Fans for drawing in air are one of the main energy consumers of DACs. As explained, waste heat from a liquid hydrocarbon synthesis reactor and / or other components (e.g., CO2 electrolyzer, water electrolyzer, etc.) may be used to drive CO2 desorption in a DAC unit. In some cases, the waste heat provides up to about 99% of the energy required for DAC desorption. Thus, in some cases, the only additional energy cost for a DAC unit is electricity to run intake fan(s). In the embodiment described here, a fan for cooling an electrolyzer and / or a liquid hydrocarbonDocket No. OPUSP049WO synthesis reactor is also used for the DAC. Thus, the capital equipment cost for the DAC unit can be shared with the CO2 electrolyzer and / or the liquid hydrocarbon synthesis reactor.

[0214] As indicated, an integrated system may include a cooling tower that is shared by a DAC unit and a CO2 electrolyzer. In such systems, the cooling tower may serve to cool cooling water that circulates in a loop. Cooling water cools the process streams in some or all units within the system (e.g., a liquid hydrocarbon synthesis reactor such as a Fischer-Tropsch reactor, a CO2 electrolyzer, a water electrolyzer a DAC unit, or any combination of these). The cooling water gains heat while cooling process streams and then travels to cooling tower where it is cooled by, e.g., air. In some embodiments, a single cooling tower is configured to cool not only some or all process units within one integrated system, but even for co-located system within a building factory or other structure.Shared Infrastructure for CO2 Electrolysis and H2O Electrolysis

[0215] In some embodiments, an integrated system includes a CO2 electrolyzer and an H2O electrolyzer. The CO2 electrolyzer may be configured to produce CO, which may be combined with H2 produced by the H2O electrolyzer to produce syngas. The integrated system may additionally include a liquid hydrocarbon synthesis reactor configured to receive the syngas and produce liquid hydrocarbons.

[0216] In some embodiments, an integrated system is configured to use waste heat to heat water used as in put to an H2O electrolyzer. The waste heat may be generated by any of various elements in the integrated system. Examples include a carbon dioxide electrolyzer and any reactor that carries out an exothermic reaction (e.g., production of liquid hydrocarbons by a Fischer-Tropsch reactor).

[0217] Some H2O electrolyzers such as solid oxide electrolyzers require vaporized water to operate. Waste heat from, e.g., a Fischer-Tropsch reactor may be employed to vaporize the water. Waste a liquid hydrocarbon synthesis reactor may be provided via a stream of tail gas, a steam stream used to carry heat away from the reactor, etc. In some embodiments, the steam from the liquid hydrocarbon synthesis reactor is used as an input to the H2O electrolyzer. In some embodiments, the steam is purified before entering the H2O electrolyzer. Regardless, the steam can at least be used to heat the water electrolyzer or the water supplied to the electrolyzer as a reactant.

[0218] Electrical integration of multiple electrolyzers such as separate H2O and CO2 electrolyzers may employ shared electrical power infrastructure. Both H2O and CO2 electrolyzers employ DC power. So, in some embodiments, an electrical unit is configured to receive AC power from, e.g., an electrical grid, convert that power to lower AC or fully to DC,Docket No. OPUSP049WO and deliver AC power to both an H2O electrolyzer and a CO2 electrolyzer. The electrical unit may comprise DC bus that provides electrical power to multiple CO2 electrolyzer stacks. In some implementations, the electrical power infrastructure is configured to minimize the loss in an electrolyzer system that utilizes multiple stacks.

[0219] In some embodiments, a liquid hydrocarbon synthesis reactor and a water electrolyzer and / or a CO2 electrolyzer share one or more compressors. A Fischer-Tropsch reactor, for example, may employ two compressors, one for recycling tail gas and another for recompressing unreacted hydrogen from a hydrocracker. If the hydrogen outlet pressure from a water electrolyzer is less than about 520PSIG, it may need to be pressurized. In such cases, an inlet for providing hydrogen from an H2O electrolyzer and a hydrogen recycle stream can share a compressor.

[0220] In some embodiments, an integrated system is configured to capture water from air (or other impure CO2 source) via a DAC unit and supply that water as an input a CO2 electrolyzer, along with the purified CO2.

[0221] Further, in systems employing an H2O electrolyzer, a CO2 electrolyzer, and a DAC unit, a shared fan or fans is configured to provide not only input air for the DAC unit but cooling air for the H2O electrolyzer and optionally also the CO2 electrolyzer. This saves fan energy for the DAC unit and spreads the cost of the fan (s) among the DAC unit and at least an H2O electrolyzer or a CO2 electrolyzer.Integrated System with a Hydrocarbon Synthesis Reactor, a CO2 Electrolyzer, and an H2O Electrolyzer

[0222] Figures 7 and 8 illustrated integrated systems for producing a fuel such as jet fuel (i.e., aviation turbine fuel). The systems in these figures each comprise one or more carbon dioxide reduction electrolyzers, one or more water electrolyzers, and one or more Fischer-Tropsch reactors. Examples of the design, components, and operation of carbon dioxide electrolyzers and water electrolyzers are described elsewhere herein. Any of the features described elsewhere herein may be applied to implement the carbon dioxide and water electrolyzers described in Figures 7 and 8.

[0223] Figure 7 depicts an integrated system 2801 comprising, inter alia, a carbon dioxide electrolyzer unit 2820, a water electrolyzer unit 2830, and a Fischer-Tropsch reactor 2850. The carbon dioxide electrolyzer unit may comprise one or more carbon dioxide electrolyzer cells and / or stacks and various optional components, as described in more detail below. Similarly, the water electrolyzer unit may comprises one or more water electrolyzer cells and / or stacks in addition to various optional components, in some embodiments. Carbon dioxide electrolyzerDocket No. OPUSP049WO unit 2820 is configured to produce carbon monoxide by reducing carbon dioxide from a feed stream delivered via a conduit 2803, while water electrolyzer unit 2830 is configured to produce molecular hydrogen (H2) by reducing water from a feed stream delivered via a conduit 2805. The carbon monoxide produced by carbon dioxide electrolyzer unit 2820 is provided in an output stream via a conduit 2822, while the hydrogen produced by water electrolyzer unit 2830 is provided in an output stream via a conduit 2832.

[0224] The carbon monoxide in the output stream may contain some unreacted carbon dioxide along with molecular hydrogen. As depicted, integrated system 2801 includes a carbon monoxide purification unit 2840 configured to receive the output stream via conduit 2822 and separate its components into a first output stream comprising purified carbon monoxide and hydrogen and a second output stream comprising purified carbon dioxide. Carbon monoxide purification unit 2840 may have any conventional or custom design. For example, such purification units may employ separation technologies based on sorbent, membranes, or cryogenics. In certain embodiments, carbon monoxide purification unit 2840 is a sorbentbased unit of the type presented in Figures 5 and 6 and the associated description. In one embodiment, carbon monoxide purification unit 2840 is a sorbent-based pressure swing separator comprising a solid sorbent that (a) at high pressure, absorbs carbon dioxide from the gas stream in conduit 2822 while passing carbon monoxide and hydrogen as the first output stream, and (b) at lower pressure, releases the purified carbon dioxide as the second output stream. In certain embodiments, the solid sorbent in carbon monoxide purification unit 2840 is a zeolite.

[0225] Integrated system 2801 is configured to utilize the second output stream of purified carbon dioxide by recycling it to an input of carbon dioxide electrolyzer unit 2820 via a recycle conduit 2842. Integrated system 2801 is further configured to transport the first output stream of purified carbon monoxide and hydrogen stream via a conduit 2844. At least a portion of the hydrogen in output stream 2832 from water electrolyzer unit 2830 is combined with the carbon monoxide and hydrogen in conduit 2844 to form syngas and transport the syngas to an input of Fischer-Tropsch reactor 2850 via a conduit 2846. In certain embodiments, integrated system 2801 is configured to feed carbon monoxide and hydrogen in a defined ratio to Fischer-Tropsch reactor 2850. As examples, the hydrogen to carbon monoxide ratio may be about 1.5:1 to 2.5:1, or about 1.8:1 to 2.1:1, or about 2:1 to 2.3:1, or about 2:1 to 2.1:1, or about 2.05:1 to 2.1:1.

[0226] Fischer-Tropsch reactor 2850 is configured to convert syngas provided via conduit 2846 to liquid hydrocarbons and tail gas. More specifically, Fischer-Tropsch reactor 2850 is configured to produce a mix of hydrocarbons, and it is outfitted with outlet lines to provideDocket No. OPUSP049WO different fractions of these hydrocarbons. In the depicted embodiment, Fischer-Tropsch reactor 2850 has four outlines that comprise a tail gas or “vent” gas outlet conduit 2852, a light cut crude outlet conduit 2854, a heavy cut crude outlet conduit 2856, and oily wastewater outlet conduit.

[0227] Heavy and light cut crude fractions are understood to those of skill in the art to define physical and chemical properties such as density, boiling point, and chemical composition. The light cut crude is sometimes referred to as “light Fischer-Tropsch liquid” or LFTL. The heavy cut crude is sometimes referred to as heavy Fischer-Tropsch liquid (HFTL) or Fischer- Tropsch wax, which may comprise a saturated paraffin.

[0228] Vent gas outlet conduit 2852 connects to vent gas or flare system outlet 2858. A flare system may simply combust the tail gas or one or more components thereof. Optionally, as described elsewhere in this disclosure, combusted tail gas may be employed to provide carbon dioxide for recycle to a carbon dioxide electrolyzer, such as carbon dioxide electrolyzer unit 2820 and / or provide heat for one or more subsystems in the integrated system 2801.

[0229] In some implementations, Fischer-Tropsch reactor 2850 comprises a main reactor and a cooling region. In some embodiments, the main reactor of Fischer-Tropsch reactor 2850 is comprised of multiple tubes filled with catalyst inside a larger shell. The main reactor may comprise an iron-based and / or a cobalt-based metal catalyst. The exothermic Fischer-Tropsch reaction produces products substantially in the gas phase. The cooling region produces the liquid heavy cut crude and light cut crude fractions. The tail gas remains a gas phase product. In some embodiments, boiler feed water is fed to the reactor to control its temperature. In some embodiments, Fischer-Tropsch reactor 2850 includes a recycle loop with a compressor.

[0230] Light cut crude outlet conduit 2854 is configured to transport the light cut crude to a product fractionation unit 2865. Integrated system 2801 also includes a conduit 2862 for delivering cracked crude (described below) to product fractionation unit 2865. Product fractionation unit 2865 is configured to separate input hydrocarbons into a naphtha component, which may be transported in an outlet conduit 2867, a fuel component such as jet fuel, which may be transported in an outlet conduit 2869, and a heavy cut crude component, which may be transported in an outlet conduit 2871. In some configurations, integrated system 2801 may provide storage for naphtha provided via conduit 2867 and / or provide storage for fuel provided via conduit 2869.

[0231] In certain embodiments, product fractionation unit 2865 may be implemented as a distillation apparatus, whose temperature and / or pressure are controlled to output naphtha and jet fuel as separate streams. Regardless of how product fractionation unit 2865 is implemented,Docket No. OPUSP049WO it may be operated in manner that produces a fuel of appropriate physical and chemical characteristics such as carbon chain size, degree of isomerization / branching, boiling point, freezing point, viscosity, vapor pressure, or any combination thereof. In certain embodiments, the fuel output has properties falling with the ranges conventionally used for aviation turbine fuel. For example, see the standards defined by ASTM D7566 Annex 1 (2022), which is incorporated herein by reference in its entirety.

[0232] In some embodiments, the hydrocarbons in the jet fuel fraction have a size of about C8 to C15 and the hydrocarbons in the naphtha fraction have a size of about C5 to CIO. In some embodiments, a naphtha stream is a mixture of hydrocarbons lighter than jet fuel. In some depicted implementations, naphtha is separated from jet fuel and subsequently recycled to a reformer. In certain embodiments, at least 90 wt% (e.g., at least 92 wt% at least 95 wt%, at least 97 wt%, at least 99 wt%, or all) of the hydrocarbons in a naphtha stream have a size of about C4 to CIO (or about C4 to C9). In some embodiments, within a naphtha stream, about 10 wt% to 40 wt%, about 15 wt% to 35 wt%, or about 20 wt% to 30 wt% of the hydrocarbons have a size of about C4 to C5. In some embodiments, within a naphtha stream, about 50 wt% to 90 wt%, about 65 wt% to 85 wt%, or about 70 wt% to 80 wt% of the hydrocarbons have a size of about C6 to C9. In some embodiments, the naphtha stream may be condensed at a temperature of about 35 °C to 50 °C, about 38 °C to 49 °C, or about 40 °C to 45 °C. Understand that this description of “naphtha” may apply to, e.g., integrated systems such as described herein.

[0233] As illustrated, heavy cut crude transported via conduits 2856 and 2871 is provided to a hydro-processing unit 2860 configured to chemically modify the heavy cut crude. As illustrated, some hydrogen from water electrolyzer unit 2830 is provided to hydro-processing unit 2860 via conduit 2832. The hydrogen is fed to hydro-processing unit 2860 reactor both to serve as a reactant and for temperature management as unit 2860 produces exothermic reactions. In some implementations, integrated system 2801 also includes a hydrogen recycle loop with a compressor.

[0234] In certain embodiments, hydro-processing unit 2860 is configured to crack heavy cut crude to produce short chain hydrocarbons in the range of naphtha and jet fuel cuts. The cracking reaction may be a catalytic reaction between hydrogen and hydrocarbons of the heavy cut crude. In some implementations, hydro-processing unit 2860 comprises a catalytic cracking sub-unit and an isomerization sub-unit (not shown). The isomerization sub-unit isomerizes hydrocarbons such as the short chain hydrocarbons produced by cracking. In some implementations, the isomerization sub-unit increases the branching of short chainDocket No. OPUSP049WO hydrocarbons. Thus, in some embodiments, hydro-processing unit 2860 contains two types of catalyst, one for cracking (breaking long chains into smaller chains) and one for isomerization. The cracked crude produced by hydro-processing unit 2860 is transported via outlet conduit 2862 to product fractionation unit 2865.

[0235] Returning to carbon dioxide electrolyzer unit 2820, it has as feedstock inlets carbon dioxide conduit 2803 and a water inlet 2807, as well as an inlet for carbon dioxide recycle conduit 2842. Carbon dioxide electrolyzer unit 2820 has three primary outlets, carbon monoxide outlet conduit 2822, an oxygen outlet conduit 2809, and an acidic wastewater outlet 2811. In alternative embodiments, acidic water produced in carbon dioxide electrolyzer unit 2820 is treated in a manner that allows it to be recycled as anode water.

[0236] As noted above, the carbon dioxide electrolyzer unit may comprise one or a plurality of carbon dioxide electrolyzers (e.g., carbon dioxide electrolyzer stacks) and optional components. Optional components may include one or more components (e.g., support components, downstream processing components, etc.) described elsewhere herein, such as an upstream purification module(s), separation unit(s), gas separator(s), circulation pump(s), recycle line(s), etc.

[0237] For example, in one set of embodiments, carbon dioxide electrolyzer unit 2820 may comprise carbon dioxide reduction electrolyzer(s) configured to receive carbon dioxide from carbon dioxide conduit 2803 and recycle conduit 2842, and water from water inlet 2807. The carbon dioxide electrolyzer(s) may be configured to output a reduction product stream comprising CO, Eh, unreacted CO2, water, along with a small amount (if any) of byproducts (e.g., formic acid, ions, etc.) at the cathode outlet. The carbon dioxide electrolyzer(s) may also be configured to output an oxidation product stream comprising anode water and oxygen at the anode outlet. In some embodiments, the reduction product stream comprising CO, Eh, unreacted CO2, water, and byproducts may be introduced to a gas-liquid separator (e.g., a water knockout) so as to remove and / or separate liquids (e.g., water and / or byproducts such formic acid) from the gases (e.g., CO / H2 / CO2) in the reduction product stream. In some embodiments, the separated gases (e.g., CO / H2 / CO2) may be transported out of electrolyzer unit 2820 via outlet conduit 2822, and some of the separated liquids may be transported out of electrolyzer unit 2820 via acidic wastewater outlet 2811 as wastewater. In some embodiments, the oxidation product stream comprising anode water and oxygen may be separated from one another via a separation unit, so that some of the separated water optionally can be recycled back to the anode of the electrolyzers via an anode recirculation loop and the oxygen can be removed via oxygen outlet conduit 2809. In some embodiments, carbon dioxide electrolysisDocket No. OPUSP049WO unit 2801 may further comprise a salt dosing system configured to introduce salt and / or ions into the anode water introduced from water inlet 2807 so as to control the salt and / or ion concentration in the anode water fed to the electrolysis unit.

[0238] Returning to water electrolyzer unit 2830, as mentioned, it has water inlet conduit 2805 as a source of water feedstock. Water electrolyzer unit 2830 has three primary outlets, hydrogen outlet conduit 2832, an oxygen outlet conduit 2813, and a wastewater outlet 2815. Oxygen outlet conduits 2813 and 2809 transport oxygen out of integrated system 2801 to storage, a reactor, or, as illustrated, the atmosphere. In some embodiments, the water electrolyzer unit, in addition to comprising one or more water electrolyzers (e.g., water electrolyzer stack(s)), may also comprise various optional components described elsewhere herein, such as one or more of the optional components described with respect to carbon dioxide unit 2820. Non-limiting examples include separation unit, gas separator, circulation pump, electrical grid, transformer, rectifiers, variable supply, mass flow meter or controller, ion exchanger, anode water recirculation loop, etc. For example, in some embodiments, the water electrolyzer unit may comprise separation units (e.g., gas separators, condensers, driers, etc.) configured to remove and / or separate liquids or moisture from gases (e.g., hydrogen and / or oxygen) in the water electrolyzer outlet streams. Some of these separated liquids may be transported out of electrolysis unit 2830 via wastewater outlet 2815, in some embodiments.

[0239] As illustrated, wastewater conduits 2815 and 2811 transport wastewater out of integrated system 2801 to storage. Additionally, carbon monoxide purification unit 2840 comprises an acid wastewater outlet connected to a conduit 2815 configured to transport the acidic wastewater to the wastewater storage mentioned here. Still further, Fischer-Tropsch reactor 2850, hydro-processing unit 2860, and product fractionation unit 2865 all may produce wastewater that is ultimately provided to storage outside integrated system 2801.

[0240] Each of the Fischer-Tropsch reactor 2850, the hydro-processing unit 2860, and the product fractionation unit 2865 may produce vent gas, as illustrated, and the vent gas from these different units may be combined and delivered to the vent gas flare system 2858.

[0241] Various optional ancillary or support units or systems are not depicted in Figure 7. These may include feedstock storage such as storage of carbon dioxide and water. In certain embodiments, liquid carbon dioxide is stored as a feedstock. The liquid carbon dioxide storage is accompanied by a vaporizer to supply to the carbon dioxide as a gas to the carbon dioxide electrolyzer unit 2820. Alternatively, in some embodiments, the feed carbon dioxide can be directly stored and supplied in gaseous form.Docket No. OPUSP049WO

[0242] Also not shown are product storage units, such as product storage for fuel provided via conduit 2869 and naphtha provided via conduit 2867. Similarly, storage or disposal systems for wastewater such as oily wastewater and acidic wastewater are not shown. Also not shown in Figure 7 are utilities such as sources of electrical power and water. Also not shown are venting and / or flaring systems. A flaring system may be used to process waste gas streams and be available to bum the gases in emergency relief scenarios to allow safe shutdown of the plant. In some embodiments, integrated system 2801 employs an enclosed flare (so no open flame).

[0243] In some implementations, integrated system 2801 employs compressors for providing differing pressures to the components, optionally at different times. In one example, the integrated system 2801 includes a compressor to boost the carbon dioxide electrolyzer’s operating pressure and improve the performance carbon monoxide purification unit 2840, a compressor to boost the syngas up to pressure for the Fischer-Tropsch reactor, and a compressor to recycle carbon dioxide to the to the carbon dioxide electrolyzer.

[0244] Examples of utilities that may be available to integrated system 2801 include cooling water, nitrogen, instrument air, deionized water, and electrical power.

[0245] Figure 8 illustrates an integrated system 2901 that includes a carbon dioxide electrolyzer unit 2920, a water electrolyzer unit 2930, and a Fischer-Tropsch reactor 2950. Each of these reactors may be implemented and arranged as described elsewhere herein, such as in Figure 7.

[0246] As illustrated, associated with carbon dioxide electrolyzer unit 2920 is an anolyte processing and recycle system that includes (a) a feedstock reservoir 2910, which has a freshwater inlet 2903 and salt inlet 2905, (b) an anolyte recycle line 2907 configured to receive anolyte used during carbon dioxide electrolysis and provided as an output of carbon dioxide electrolyzer unit 2920, and (c) an anolyte feed line 2909 connecting feedstock reservoir 2910 to carbon dioxide electrolyzer unit 2920. Anolyte feedstock storage unit 2910 is configured to combine fresh salt and water with used anode water in a manner that produces carbon dioxide anolyte feed of appropriate composition which can be output via anolyte feed line 2909 and provided to carbon dioxide electrolyzer unit 2920.

[0247] A carbon dioxide feedline 2911 is connected to the cathode side of carbon dioxide electrolyzer unit 2920 and provides carbon dioxide feedstock. A water feedline 2913 is connected to and provides fresh water to water electrolyzer unit 2930. During operation, the anodes of both carbon dioxide electrolyzer unit 2920 and water electrolyzer unit 2930 generate oxygen, which is removed from the electrolyzers via conduits 2913 and 2915, respectively. During operation, both carbon dioxide electrolyzer unit 2920 and water electrolyzer unit 2930Docket No. OPUSP049WO generate wastewater, which is removed from the electrolyzers via conduits 2917 and 2919, respectively.

[0248] Integrated system 2901 also includes a carbon monoxide enrichment unit 2940, which may be designed or configured in a manner similar to that of carbon monoxide purification unit 2840 of Figure 7, including having an inlet configured to receive an output stream of carbon monoxide, carbon dioxide, and hydrogen from the cathode side of carbon dioxide electrolyzer unit 2920 via a conduit 2921. Carbon monoxide enrichment unit 2940 also includes two outlets, a first one connected to a conduit 2923 for delivering a stream of syngas to Fischer- Tropsch reactor 2950, and a second one connected to a recycle conduit 2925 for recycling purified carbon dioxide to the cathode side of carbon dioxide electrolyzer unit 2920. In some implementations, carbon monoxide enrichment unit 2940 is a sorbent-based, pressure swing separator.

[0249] Fischer-Tropsch reactor 2950 is configured with an inlet to receive syngas comprising(a) hydrogen provided via a conduit 2927 from the cathode side of water electrolyzer unit 2930,(b) a mixture of carbon monoxide and hydrogen provided via conduit 2923, and syngas produced by reforming (described later) and provided via a conduit 2929. During operation, Fischer-Tropsch reactor 2950 produces light cut crude output via a conduit 2931 and heavy cut crude output via a conduit 2933. As byproducts of the reaction, Fischer-Tropsch reactor 2950 produces tail gas that exits the reactor via a conduit 2955 and wastewater that exits the reactor via a conduit 2935. Fischer-Tropsch reactor 2950 may be implemented in a manner similar or identical to Fischer-Tropsch reactor 2840 of integrated system 2801.

[0250] Integrated system 2901 also includes a hydro-processing unit 2960 which has as inlets for receiving (a) heavy cut crude via conduit 2933 and a conduit 2945, and (b) hydrogen gas via conduit 2927. Hydro-processing unit 2960 may be designed or configured to operate in a manner identical to or similar to hydro-processing unit 2860 of Figure 7. Thus, it may catalytically crack heavy cut crude by reaction with hydrogen. It may also isomerize the cracked hydrocarbons. The outputs of hydro-processing unit 2860 include cracked crude (a conduit 2937), purge gas (a conduit 2939), tail gas (a conduit 2941), and wastewater (a conduit 2943).

[0251] Additionally, integrated system 2901 includes a product fractionation unit 2965, which has inputs for light cut crude (conduit 2931) and cracked crude (conduit 2937). Product fractionation unit 2965 has outputs for heavy cut crude (conduit 2945) to hydro-processing unit 2960, for providing naphtha (a conduit 2947) to storage, and for providing fuel (a conduit 2949) to storage. Product fractionation unit 2965 also has outlets for purge gas (a conduit 2951) andDocket No. OPUSP049WO wastewater (a conduit 2953). Product fractionation unit 2965 may be designed or configured in a manner identical to or similar to that described for product fractionation unit 2865 of Figure 7.

[0252] As illustrated, integrated system 2901 also comprises a reformer elements that are not present in the implementation illustrated in Figure 7. Specifically, integrated system, 2901 includes a methane reformer such as an auto thermal reformer 2970 and an auto thermal reformer cleanup unit 2975.

[0253] A reformer converts hydrocarbons such as methane present in tail gas from the Fischer- Tropsch and hydro-processing reactors and converts them, through a reforming process, to hydrogen, typically with some carbon monoxide, which can be used as syngas and input to the Fischer-Tropsch reactor. In this manner, a gaseous hydrocarbon outputs of the Fischer-Tropsch and hydro-processing reactors, which output would otherwise be wasted or combusted, are converted to a useful input, syngas, for reaction in the Fischer-Tropsch reactor and thereby increasing the overall efficiency of integrated system 2901.

[0254] Auto thermal reformer 2970 is configured to receive as inputs tail gas via lines 2955 and 2941. It is also configured to receive oxygen as an input via line 2915. Auto thermal reactor 2970 is configured to partially oxidize the tail gas in the presence of steam to produce syngas via a reforming reaction.

[0255] Syngas produced by auto thermal reformer 2970 is output via a conduit 2957, which delivers the syngas to auto thermal reformer cleanup unit 2975, which in turns cleans the gas using water provided via a conduit 2959. The resulting clean syngas exits via conduit 2929 and is thereby supplied as an input to Fischer-Tropsch reactor 2950. Auto thermal reformer cleanup unit 2975 also produces wastewater, which exits integrated system 2901 along with wastewater from various other units in the system. In some embodiments, auto thermal reformer cleanup unit 2975 may remove impurities such hydrogen cyanide and / or ammonia that could otherwise poison a catalyst in Fischer-Tropsch reactor 2950. In some embodiments, auto thermal reformer cleanup unit 2975 comprises an HCN reactor and wash tower with water. Integrated System with a Hydrocarbon Synthesis Reactor, a CO2 Electrolyzer, an H2O Electrolyzer, and a Naphtha Reforming Unit

[0256] In certain aspects, systems and methods directed to the integration of carbon oxide electrolyzer with naphtha reforming is disclosed herein. Non-limiting examples of such embodiments are illustrated in Figures 9A-10D.

[0257] In some embodiments, an integrated system comprising a carbon oxide reduction electrolyzer, a liquid hydrocarbon synthesis system downstream the carbon oxide reductionDocket No. OPUSP049WO electrolyzer, and a naphtha reforming unit downstream the liquid hydrocarbon synthesis system is described herein. In some embodiments, the carbon oxide reduction electrolyzer (e.g., carbon dioxide (CO2) reduction electrolyzer) may be configured to electrochemically reduce a carbon oxide (e.g., carbon dioxide (CO2)) into a carbon-containing reduction product (e.g., carbon monoxide (CO)). In some embodiments, the liquid hydrocarbon synthesis system may be configured to produce liquid hydrocarbon products from hydrogen gas (H2) from one or more hydrogen sources and at least a portion (e.g., at least 10%, at least 25%, at least 50%, and up to 75%, up to 90%, or up to 100%) of the carbon-containing reduction product (e.g., CO) produced by the carbon oxide reduction electrolyzer. The one or more hydrogen sources may include a water electrolyzer and / or a carbon oxide reduction electrolyzer. In some cases, the produced liquid hydrocarbon products may comprise naphtha and at least one other liquid hydrocarbon product, such as jet fuel, diesel, petroleum, etc. In some cases, the naphtha reforming unit may be configured to produce a syngas stream from the naphtha produced by the liquid hydrocarbon synthesis system. The naphtha reforming unit, according to some embodiments, may in turn transport at least a portion (e.g., at least 10%, at least 25%, at least 50%, and / or up to 75%, up to 90%, or up to 100%) of the produced syngas to the liquid hydrocarbon synthesis system as an additional source of feedstock for producing more fuel products (e.g., jet fuel, diesel, etc.).

[0258] Figure 9A can be used to illustrate the embodiment described above. For example, integrated system 1000 may comprise carbon oxide reduction electrolyzer(s) 1050, liquid hydrocarbon synthesis system 1100 downstream carbon oxide reduction electrolyzer(s) 1050, and naphtha reforming unit 1200 downstream the liquid hydrocarbon synthesis system. Carbon oxide reduction electrolyzer(s) 1050 (e.g., carbon dioxide (CO2) reduction electrolyzer(s)) may be configured to electrochemically reduce a carbon oxide (e.g., carbon dioxide (CO2)) into a carbon-containing reduction product (e.g., carbon monoxide (CO)). Liquid hydrocarbon synthesis system 1100 may in turn be configured to produce liquid hydrocarbon products (e.g., naphtha and at least one other liquid hydrocarbon product such as jet fuel) from hydrogen gas (H2) and at least a portion of the carbon-containing reduction product (e.g., CO) produced by carbon oxide reduction electrolyzer 1050. At least a portion of the hydrogen gas introduced into liquid hydrocarbon synthesis system 1100 may be produced by water electrolyzer 1150 and / or carbon oxide reduction electrolyzer 1050. Naphtha reforming unit 1200 may in turn be configured to produce syngas from the naphtha produced by liquid hydrocarbon synthesis system 1100 and transport at least a portion of the produced syngas to liquid hydrocarbonDocket No. OPUSP049WO synthesis system 1100 as an additional source of feedstock for producing more fuel products (e.g., jet fuel, diesel, etc.).

[0259] The carbon oxide reduction electrolyzer described herein may have any appropriate configuration and / or comprise one or more components described elsewhere herein. For example, the carbon oxide reduction electrolyzer may comprise a cathode layer having a reduction catalyst and an ion-conducting polymer in contact with a polymer electrolyte membrane for facilitating chemical reduction of the carbon dioxide to carbon monoxide. The carbon oxide reduction electrolyzer may also have any appropriate input and / or output as described elsewhere herein, such as an anode side input of water (e.g., salt water) and / or hydrogen gas, a cathode side input of carbon oxide (e.g., CO2), an anode side output of oxygen (e.g., O2), an cathode side output of CO and H2.

[0260] The naphtha reforming unit described herein (e.g., as shown in Figures 9A-10D) may include, according to some embodiments, a reformer reactor and an external heater or furnace, such as having a configuration illustrated in Figure 4B (e.g., reformer 645 and furnace 651). In some embodiments, while the reformer reactor reacts the naphtha to produce a syngas stream for recycling into the liquid hydrocarbon reactor (e.g., Fischer-Tropsch reactor), the external heater coupled to the reformer reactor may (i) produce an exhaust stream containing CO2 that can be recycled to the carbon oxide reduction electrolyzer, and (ii) provide heat to the reformer reactor, as described in more detail below. The naphtha reforming unit described herein may comprise one or more of an autothermal reformer, a naphtha steam reformer, a partial oxidation reformer, in some embodiments. In some cases, the naphtha reforming unit may comprise one or more of an external heater thermally coupled to the reformer reactor, such as a fired heater, an electrical heater, and / or a reformer furnace. In some embodiments, the naphtha reforming unit may include a naphtha steam reformer thermally coupled to an external heater. Alternatively, in some embodiments, the naphtha reforming unit may lack an external heater and may include one or more of a reformer described above (e.g., autothermal reformer, a partial oxidation reformer, etc.).

[0261] Figure 9B-9C can be used to illustrate a naphtha reforming unit (e.g., a steam naphtha reforming unit) comprising an external heater or furnace 651 thermally coupled to a naphtha reformer reactor 645 (e.g., a steam naphtha reformer). Similar to as described in Figure 4B, carbon oxide reduction electrolyzer 636 may be configured to electrochemically produce CO and / or syngas 637 for use in a liquid hydrocarbon synthesis reactor (e.g., Fischer-Tropsch reactor 638). Liquid hydrocarbon mixture 642 may be produced and separated into various liquid hydrocarbon products 644, e.g., including naphtha 642 and at least one other productsDocket No. OPUSP049WO(e.g., jet fuel), via fractionation or separation unit 643. The produced naphtha 642 (and tail gas 641 generated from Fischer-Tropsch reactor 638) may be provided to naphtha reforming reactor 641 to produce additional syngas 647 for use in Fischer-Tropsch reactor 638. Furnace 651, as shown, may be employed to combust a fuel with oxygen 649 (via oxy-combustion) to produce an exhaust stream containing CO2 (e.g., a high purity CCh-containing stream) and provide heat for reformer reactor 645. While at least a portion of the produced CO2 may be recycled to a cathode of carbon oxide reduction electrolyzer 636, at least a portion of the produced CO2 may be recirculated back to furnace 651 to control the flame temperature within furnace 651 to be within desired range. In some cases, the exhaust stream containing CO2 may be further purified via a gas purification unit 660 prior to being delivered to carbon oxide reduction electrolyzer 636. In some cases, at least a portion of the hydrocarbons (e.g., tail gas 641 and / or hydrocarbon products such as naphtha 642) produced by the hydrocarbon synthesis reactor may be optionally purified and then introduced as fuel 656 to furnace 651.

[0262] While Figure 9B illustrates an embodiment in which oxygen 649 produced from electrolysis is used for combustion in furnace 651, it should be understood that the disclosure is not so limited and that in certain embodiments, any appropriate oxy gen-containing stream may be employed as a feed. For example, as shown in Figure 9C, air may be fed into furnace 651 for combustion and an exhaust stream containing CO2 and impurities such as N2 and O2 may be produced. The exhaust stream may be released to the environment and subsequently captured using any appropriate method and / or system described elsewhere herein, such as via a direct air capture (DAC) unit 665. The captured CO2 may be recycled into carbon oxide reduction electrolyzer to produce additional CO and / or syngas, according to some embodiments.

[0263] Referring back to Figure 9A, liquid hydrocarbon synthesis system 1100 may include one or more reactors or units described elsewhere herein. For example, the liquid hydrocarbon synthesis system may comprise a liquid hydrocarbon synthesis reactor (e.g., a Fischer-Tropsch reactor), a hydro-processing unit downstream the liquid hydrocarbon synthesis reactor, and a fractionation unit downstream the hydro-processing unit. The one or more reactors may have any appropriate properties and / or arrangements as described elsewhere herein, such as units 2950, 2960, and 2965 as shown in Figure 8. In one set of embodiments, the liquid hydrocarbon synthesis reactor (e.g., Fischer-Tropsch reactor) may be configured to produce a liquid hydrocarbon mixture from hydrogen gas (H2) and at least a portion of the carbon-containing reduction product (e.g., CO) produced by carbon oxide reduction electrolyzer. The produced liquid hydrocarbon mixture may be subjected to hydro-processing and subsequently productDocket No. OPUSP049WO fractionation to produce different streams of separated (and purified) fuel cuts (e.g., naphtha, jet fuel, diesel, etc.).

[0264] In some embodiments, integrated system 1000 may comprise additional components, such as various upstream systems 1025 (e.g., DAC units), as well as a gas purification unit (not shown) positioned between carbon oxide reduction electrolyzer 1050 and liquid hydrocarbon synthesis system 1100. In some cases, the gas purification unit is a CO purification unit described elsewhere herein. The gas purification unit, according to some embodiment, is configured to purify one or more product streams (e.g., syngas, CO2-containing stream) produced by the naphtha reforming unit prior to recycling the product streams to various parts of the system, e.g., recycling the purified syngas the liquid hydrocarbon synthesis system and / or recycling the purified CO2 stream to the carbon oxide reduction electrolyzer. Examples of gas purification or separation units are presented in Figures 5, 6, 7, and 8, and the associated description. In some cases, the gas purification unit is a sorbent-based, pressure-swing purification unit.

[0265] Figure 10A illustrates an integrated system 3910A that includes a carbon dioxide electrolyzer unit 3920, a water electrolyzer unit 3930, a Fischer-Tropsch reactor 3950, and a naphtha reforming unit 3970. Each of these reactors and units may be implemented and arranged as described elsewhere herein.

[0266] As illustrated, associated with carbon dioxide electrolyzer unit 3920 is an anolyte processing and recycle system that includes (a) a feedstock reservoir 3910, which has a freshwater inlet 3903 and salt inlet 3905, (b), an anolyte system 3908, (c) an anolyte recycle line 3907 configured to receive anolyte used during carbon dioxide electrolysis and provided as an output of carbon dioxide electrolyzer unit 3920, and (d) an anolyte feed line 3909 connecting anolyte system 3908 to carbon dioxide electrolyzer unit 3920. Anolyte system 3908 is configured to combine brine and water with used anode water in a manner that produces carbon dioxide anolyte feed of appropriate composition which can be output via anolyte feed line 3909 to carbon dioxide electrolyzer unit 3920. In some cases, anolyte system 3908 may comprise an oxygen separator unit configured to separate water from oxygen, such that oxygen produced by carbon dioxide electrolyzer 3913 is separated for later use in naphtha reforming unit 3970 and the oxygen-poor water can be recycled to the carbon oxide electrolyzer unit.

[0267] A carbon dioxide feedline 3911 is connected to feedstock reservoir 3910, which is then connected via feedline 3908 to the cathode side of carbon dioxide electrolyzer unit 3920 to provide carbon dioxide feedstock. A water feedline 3913 from feedstock reservoir 3910 is connected to and provides fresh water to water electrolyzer unit 3930. During operation, theDocket No. OPUSP049WO anodes of both carbon dioxide electrolyzer unit 3920 and water electrolyzer unit 3930 generate oxygen, which is removed from the electrolyzers via conduits 3913 and 3915, respectively. During operation, both carbon dioxide electrolyzer unit 3920 and water electrolyzer unit 3930 generate wastewater, which is removed from the electrolyzers via conduits 3917 and 3919, respectively.

[0268] Integrated system 3901A also includes a carbon monoxide purification unit 3940, which may be designed or configured in a manner similar to that of carbon monoxide purification unit 2840 or 2940 of Figures 7-8, including having an inlet configured to receive an output stream of carbon monoxide, carbon dioxide, and hydrogen from the cathode side of carbon dioxide electrolyzer unit 3920 via a conduit 3921. Carbon monoxide purification unit 3940 also includes two outlets, a first one connected to a conduit 3923 for delivering a stream of CO (and H2) to a liquid hydrocarbon synthesis reactor (e.g., Fischer-Tropsch reactor 3950), and a second one connected to a recycle conduit 3925 for recycling purified carbon dioxide to the cathode side of carbon dioxide electrolyzer unit 3920. In some implementations, carbon monoxide purification unit 3940 is a sorbent-based, pressure swing separator.

[0269] Fischer-Tropsch reactor 3950 is configured with an inlet to receive syngas comprising(a) hydrogen provided via a conduit 3927 from the cathode side of water electrolyzer unit 3930,(b) a mixture of carbon monoxide and hydrogen provided via conduit 3923, and syngas produced by reforming of naphtha and tail gas (described later) and provided via a conduit 3929. The produced syngas stream 3929 may be rich in CO and / or syngas and may contain some amount of impurities (e.g., CO2). During operation, Fischer-Tropsch reactor 3950 produces light cut crude output via a conduit 3931 and heavy cut crude output via a conduit 3933. As byproducts of the reaction, Fischer-Tropsch reactor 3950 produces tail gas that exits the reactor via a conduit 3955 and wastewater that exits the reactor via a conduit 3935. Fischer- Tropsch reactor 3950 may be implemented in a manner similar or identical to Fischer-Tropsch reactor 2850 and 2950 of integrated systems 2801 and 2901.

[0270] Integrated system 3901 A also includes a hydro-processing unit 3960 which has an inlets for receiving (a) heavy cut crude via conduit 3933 and a conduit 3945, and (b) hydrogen gas via conduit 3927. Hydro-processing unit 3960 may be designed or configured to operate in a manner identical to or similar to hydro-processing unit 2880 or 2960 of Figures 7-8. Thus, it may catalytically crack heavy cut crude by reaction with hydrogen. It may also isomerize the cracked hydrocarbons. The outputs of hydro-processing unit 3860 include cracked crude (a conduit 3937), purge gas (a conduit 3939), tail gas (a conduit 3941), and wastewater (a conduit 3943).Docket No. OPUSP049WO

[0271] Additionally, integrated system 3901 includes a product fractionation unit 3965, which has inputs for light cut crude (conduit 3931) and cracked crude (conduit 3937). Product fractionation unit 3965 has outputs for heavy cut crude (conduit 3945) to hydro-processing unit 3960, for producing naphtha (via a conduit 3947) and providing at least a portion of the produced naphtha to naphtha reformer 3970 (via conduit 3971), and for producing and providing fuel (e.g., jet fuel) via a conduit 2949 to storage. Product fractionation unit 3965 also has outlets for purge gas (a conduit 3951) and wastewater (a conduit 3953). Product fractionation unit 3965 may be designed or configured in a manner identical to or similar to that described for product fractionation unit 2865 or 2965 of Figures 7-8.

[0272] As illustrated, integrated system 3901A also comprises a naphtha reforming unit 3970. A naphtha reformer converts naphtha 3971 (as well as other hydrocarbons such as methane present in tail gas 3941 and 3955) from the Fischer-Tropsch and hydro-processing reactors and converts them, through a reforming process, to hydrogen, typically with some carbon monoxide, which can be used as syngas and input to the Fischer-Tropsch reactor. In this manner, the gaseous hydrocarbon outputs of the Fischer-Tropsch and hydro-processing reactors, which would otherwise be wasted or combusted, are converted to a useful input, syngas, for reaction in the Fischer-Tropsch reactor and thereby increasing the overall efficiency of integrated system 3901A. During the reforming, depending on the type of reforming, additional inputs such as oxygen (e.g., oxygen 3913 produced from carbon dioxide electrolyzer unit 3920 and / or oxygen 3915 from water electrolyzer unit 3930) and / or steam (e.g., stream 3959) may be introduced to the naphtha reforming unit.

[0273] As shown in Figure 10A, in integrated system 3901A, liquid hydrocarbon synthesis system comprises a reactor inlet (e.g., inlet of Fischer-Tropsch reactor 3950) configured to receive H2 and CO via conduit 3924 and a reactor outlet (e.g., outlet of production fractionation unit 3965) configured to output naphtha 3947. As shown, naphtha reforming unit 3971 comprises a first reformer inlet fluidically connected to the reactor outlet, where the first reformer inlet is configured to receive at least a portion of naphtha 3971 from the reactor outlet. Naphtha reforming unit 3970 further comprises a first reformer outlet fluidically connected to the reactor inlet of Fischer-Tropsch reactor 3950, where the first reformer outlet is configured to output at least a portion of the syngas (via conduit 3929) produced by naphtha reforming unit 3970 to the reactor inlet of Fischer-Tropsch reactor 3950.

[0274] Integrated system 3901A may include additional components, such as an AC power distribution unit 3980 fluidically connected to DC power modules 3985. AC power distribution unit 3980 may be configured to supply AC power from utility (via power line 3981) to waterDocket No. OPUSP049WO electrolyzer unit 3930 and to DC power modules 3985, where AC power is converted to DC power for supplying power to carbon dioxide electrolyzer unit 3920.

[0275] While Figure 10A illustrates an integrated system in which syngas produced from the naphtha reformer is directly supplied to a portion of the liquid hydrocarbon synthesis system (e.g., Fischer-Tropsch reactor 3950), it should be understood that the disclosure is not so limited and that in certain embodiments, the syngas produced from the naphtha reformer may be first purified via a gas purification unit prior to being sent to the liquid hydrocarbon synthesis system. A non-limiting example of one such embodiment is shown in Figure 10B.

[0276] In some embodiments, depending on the type of naphtha reformer employed in the integrated system and the purity of the produced syngas, it may be advantageous to purify the produced syngas (by removing other components such as CO2) prior to recycling the syngas to the liquid hydrocarbon synthesis system. For example, as shown in integrated system 3901B in Figure 10B, at least a portion (e.g., at least 10%, at least 25%, at least 50%, and / or up to 75%, up to 90%, or up to 100%) of syngas 3929 produced by naphtha reforming unit 3970 may be sent to a gas purification unit (e.g., CO purification unit 3940) to produce a purified syngas stream prior to being sent to the liquid hydrocarbon synthesis reactor (e.g., Fischer-Tropsch reactor 3950). In some embodiments, one or more detectors may be employed to monitor the composition of the produced syngas 3929 to detect the concentration of CO and / or syngas relative to other components (e.g., CO2). Depending on the measured concentration, the produced syngas may be either introduced directly to the downstream liquid hydrocarbon synthesis reactor (e.g., as shown in Figure 10A) or purified by the gas purification unit prior to being sent to the liquid hydrocarbon synthesis reactor (e.g., as shown in Figure 10B).

[0277] In some embodiments, depending on the type and / or configuration of the naphtha reforming unit, the naphtha reforming unit may be further configured to produce a CO2 - containing stream (e.g., an exhaust stream). The CO2 - containing stream may be rich in CO2 relative to other components (e.g., CO, etc.), according to some embodiments. For example, in embodiments in which the naphtha reforming unit comprises an external heater or furnace, a CO2-rich exhaust stream may be produced from the external heater (e.g., as illustrated in Figures 9A-9C). As shown in Figure 10C, in addition to producing syngas 3920, naphtha reforming unit 3970 may also produce a CO2 - containing stream 3971 from the associated furnace. Naphtha reforming unit 3970, in addition to comprising a first reformer outlet for outputting syngas 3929, may also comprise a second reformer outlet configured to output CO2 - containing stream 3971. As shown, the second reformer outlet for outputting CO2 - containing stream 3971 may be fluidically connected to a cathode inlet of CO2 electrolyzer unit 3920.Docket No. OPUSP049WO

[0278] In some embodiments, as shown in Figure 10B, at least a portion of CO2 - containing stream 3971 may be recycled to the cathode of CO2 electrolyzer unit 3920 as a cathode side CO2 feedstock. In some cases, depending on the purity of CO2 within the CO2 - containing stream, the CO2 - containing stream may be either directly recycled to feedstock reservoir 3910 for use in carbon dioxide electrolyzer unit 3920, or sent to a purification unit to remove impurities prior to being recycled to carbon dioxide electrolyzer unit 3920, such as purification unit 660 as shown in Figure 9B. Alternatively or additionally, as shown in Figure 10C, at least a portion (e.g., at least 10%, at least 25%, at least 50%, and / or up to 75%, up to 90%, or up to 100%) of the CO2 - containing stream produced by naphtha reforming unit 3970 in integrated system 3910C may be introduced to a gas purification unit (e.g., purification unit 3940) to produce a purified CO2 stream prior to being introduced into carbon dioxide electrolyzer unit 3920.

[0279] In some embodiments, within the gas purification unit (e.g., CO purification unit), CO2 may be separated from CO (or syngas) to produce a purified CO2 stream and a purified CO (or syngas) stream. The gas purification unit may comprise a plurality of inlets configured to receive product streams from various upstream units. For example, as shown in Figure 10C, the gas purification unit (e.g., CO purification unit 3940) may comprise (i) a first inlet configured to receive cathode product stream 3921 comprising CO2, CO, and H2 from carbon dioxide electrolyzer unit 3920, and (ii) additional inlet(s) configured to receive syngas stream 3929 and / or CO2 - containing stream 3972 from various outlet(s) of naphtha reforming unit 3970. Within CO purification unit 3940, CO2 may be separated from CO (or syngas) to produce purified CO2 stream 3925 and purified syngas stream 3923. The gas purification unit may comprise a plurality of outlets configured to output purified streams to various downstream units. For example, as shown in Figure 10C, gas purification unit (e.g., CO purification unit 3940) may comprise (i) a first outlet fluidically connected to a cathode inlet of carbon dioxide electrolysis system 3920 and configured to recycle at least a portion of purified CO2 stream 3925 to the cathode inlet, and (ii) a second outlet fluidically connected to the reactor inlet of Fischer- Tropsch reactor 3950 and configured to provide at least a portion of purified syngas stream 3923 to the reactor inlet.

[0280] While Figures 10A-10C illustrate an embodiment in which the integrated system comprises a single reforming unit, it should be understood that the disclosure is not so limited and that in certain embodiments, the integrated system may comprise two or more reforming units. A non-limiting example of one such embodiment is shown in Figure 10D.Docket No. OPUSP049WO

[0281] As shown, integrated system 39 IOC comprises two reformers - a reforming unit 3970a configured to reform at least a portion of the tail gas (e.g., methane) from the liquid hydrocarbon synthesis system (e.g., tail gas 3955 and 3941 from Fischer-Tropsch reactor 3950 and hydro-processing unit 3960, respectively), and a naphtha reforming unit 3970b configured to reform at least a portion of naphtha 3971 produced by the liquid hydrocarbon synthesis system (e.g., naphtha 3947 from product fractionation unit 3965). Other feed such as oxygen (via conduit 3913) produced by carbon dioxide electrolyzer unit 3920 and / or steam (conduit 3914) may also be provided to reforming unit 3970b.

[0282] In some cases, each of reforming units 3970a and 3970b may be configured to produce syngas streams 3929a and 3929b, respectively, and provide these syngas streams to the liquid hydrocarbon synthesis reactor (e.g., Fischer-Tropsch reactor 3950). Although not shown, syngas streams 3929a and / or 3929b, according to some embodiments, may be first introduced into a gas purification unit (e.g., CO purification unit 3940) to become purified prior to being introduced into the liquid hydrocarbon synthesis reactor, similar to as described elsewhere herein. Additionally or alternatively, similar to naphtha reforming unit 3970 as shown in Figures 10B-10C, naphtha reforming unit 3970b may be configured to produce a CO2 - containing stream 3973 (e.g., an exhaust stream) that can be either (i) recycled directly to a cathode of the carbon dioxide electrolysis unit 3920 (e.g., as shown in Figure 10B), or (ii) first purified in a gas purification unit (e.g., purification unit 3940) and then recycled to carbon dioxide electrolyzer unit 3920 (e.g., as shown in Figure 10C).

[0283] In some embodiments, a method of reforming naphtha using the integrated systems described herein is disclosed. For example, as shown in Figure 10B, the method may first comprise chemically (e.g., electrochemically) reducing carbon dioxide (CO2) to carbon monoxide (CO) using a carbon dioxide electrolyzer unit 3920. Next, the method may comprise introducing hydrogen gas (H2) (e.g., from water electrolyzer unit 3930 and / or carbon oxide electrolyzer unit 3920) and at least a portion of the CO (via conduit 3921) produced by carbon dioxide electrolyzer unit 3920 to a liquid hydrocarbon synthesis system (e.g., Fischer-Tropsch reactor 3950) to produce liquid hydrocarbon products (e.g., naphtha 3947 and at least one other liquid hydrocarbon product such as jet fuel 3949). According to some embodiments, the method further comprises reforming at least a portion of naphtha 3971 produced by the liquid hydrocarbon synthesis system in naphtha reforming unit 3970 to produce syngas stream 3929 and optionally CC -containing stream 3971 (e.g., an exhaust stream). At least a portion of syngas stream 3929 produced by naphtha reforming unit 3970 may be introduced to the liquid hydrocarbon synthesis system (e.g., Fischer-Tropsch reactor 3950) to produce additional fuelsDocket No. OPUSP049WO(e.g., jet fuels). Alternatively or additionally, CCh-containing stream 3971 may be recycled to a cathode of carbon dioxide electrolyzer unit 3920. In some instances, as described elsewhere herein, syngas stream 3929 and optionally CCh-containing stream 3972 may be purified prior to being introduced to downstream units (e.g., purified syngas stream sent to Fischer-Tropsch reactor 3950 and purified CO2 sent to carbon dioxide electrolyzer unit, respectively).Reforming Tail Gas and / or Naphtha

[0284] In some implementations such as those depicted in Figures 9A-10D, a steam naphtha reformer may be employed. The steam naphtha reformer unit, according to some embodiments, may produce two CCh-containing streams (e.g., streams 3929 and 3972 in Figure 10B): (1) the tail gas, as described above, which comes from the reactor, and (2) flue gas (i.e., exhaust gas), which comes from the furnaces that are used to heat the reactor tubes and generate steam for the reaction. The tail gas may contain fairly high concentrations of carbon dioxide (e.g., about 15% before separation and then about 50% after separation). The flue gas may have a relatively lower concentration of carbon dioxide (e.g., only about 3-5% CO2 concentration). In various implementations, about two thirds of the carbon dioxide emissions are from the tail gas, and about one-third are from the flue gas. In some embodiments, one or more of the CO2- containing streams may be purified prior to being sent to downstream units (e.g., carbon oxide electrolyzer, Fischer-Tropsch, etc.). The steam naphtha reforming unit may have a configuration illustrated in Figures 9B-9C.

[0285] In some embodiments, one or more external heaters (e.g., a fired heater and / or reforming furnace) may be present in and / or associated with the naphtha reforming unit. In some embodiments, oxygen and steam may be fed into the fired heater, where reforming reaction occurs in the process side of the reactor to produce syngas and heating occurs on the other side of the reactor to produce an CO2 exhaust stream. The CO2 exhaust stream can be purified and recycled to be used as a feed for the CO2 electrolyzer, while the syngas can be sent to the Fischer-Tropsch reactor either directly or after being purified.

[0286] In some cases, an autothermal reforming (ATR) reactor may be employed as the naphtha reforming unit. An autothermal reformer may be configured to receive naphtha (and tail gas containing methane from, e.g., a Fischer-Tropsch reactor), and reform the hydrocarbons to syngas. An ATR reactor uses oxygen and carbon dioxide or steam in a reaction with naphtha (and tail gas) to form syngas. The reaction is exothermic. When an ATR reactor uses carbon dioxide, the FhiCO ratio produced is about 1:1; when an ATR reactor uses steam, the FhiCO ratio produced is about 2.5:1. The outlet temperature of the syngas is about 950 to 1100 °C, and the outlet pressure can be as high as about lOObar.Docket No. OPUSP049WO

[0287] In some embodiments, the output of an ATR reactor includes unreacted carbon dioxide. In such embodiments, an integrated system may be configured to remove or reduce the CO2 in the output stream from the ATR reactor before feeding the resulting syngas into the liquid hydrocarbon synthesis reactor. This design should be compared with designs that feed the CO2 into the liquid hydrocarbon synthesis reactor and allowing it to build up, which requires purging and therefore lower CO2 utilization.

[0288] In short, the sequence of operations includes: (a) receive tail gas and / or naphtha produced in a liquid hydrocarbon synthesis reactor in an ATR reactor, (b) react the tail gas to produce syngas that contains CO2, (c)(1) feed the syngas that includes CO2 to the liquid hydrocarbon production reactor, or (c)(2) feed the syngas that includes CO2 into a CO2 removal system, and (d) feed the purified into the liquid hydrocarbon production reactor. The path that includes (c)(2) and (d) results in less CO2 buildup and avoids the concomitant purge. A nonlimiting example of an ATR for naphtha reforming can be illustrated by reforming unit 3970 shown in Figures 10A-10B.

[0289] In certain embodiments, an integrated system comprises a liquid hydrocarbon synthesis reactor (e.g., a Fischer-Tropsch reactor) and a combustion furnace configured to combust tail gas produced by the liquid hydrocarbon synthesis reactor. In some implementations, discussed herein, tail gas is employed as a sweep gas in a pressure-mediated CO2 purification unit (e.g., a DAC unit). In such implementations, the spent tail gas may be combusted, and the resulting heat may be used in a different process. Examples of such other processes include creating steam, boiling water, etc.

[0290] Some integrated systems may employ a CO2 electrolyzer, a liquid hydrocarbon synthesis reactor, and partial oxidation reactor. A partial oxidation reaction may be thermal or catalytic. It uses sub- stoichiometric oxidant (e.g., oxygen) and can produce a CO-rich output stream. In some implementations, oxygen (optionally from the CO2 electrolyzer and / or an H2O electrolyzer) reacts with light hydrocarbons (e.g., methane) from a tail gas in partial oxidation reactor. Such systems may create CO that can supplement CO produced by a CO2 electrolyzer. A combined CO stream from the electrolyzer and the partial oxidation reactor can be directed to the liquid hydrocarbon production reactor. In some cases, partial oxidation reactor may be employed for naphtha reforming. In some such embodiments, oxygen is employed as a feed in addition to naphtha (and the tail gas from the Fischer-Tropsch) to produce a syngas stream comprising a relatively high amount of CO2. The syngas stream may be purified prior to being recycled into the CO2 electrolyzer unit, e.g., as shown in Figure 10B.Docket No. OPUSP049WO

[0291] In some embodiments, the integrated systems comprising carbon oxide electrolyzer unit integrated with the naphtha reforming unit may offer several advantages compared to systems without the naphtha reforming unit. For example, the presence of the naphtha reforming unit may allow for recycling and conversion of naphtha into higher value fuel products. This would increase the yield of higher value fuel products (e.g., jet fuel) over naphtha, leading to at least 10%, at least 20%, at least 50%, at least 70% increased production of higher value fuel products. Furthermore, the syngas produced from naphtha reforming may serve as an additional source of syngas (aside from the syngas produced by the carbon oxide electrolyzer unit), which would then allow the downstream liquid hydrocarbon synthesis reactor (e.g., Fischer-Tropsch reactor unit) and / or the integrated system to continue operating even if electrolysis is interrupted during operation. This may in turn allow for (i) better time-power matching with renewable energy without adverse effects to Fischer-Tropsch reactor operation, and (ii) safer shutdown in case of sudden power loss to the electrolyzer system. Specifically, current state-of-the-art Fischer-Tropsch reactors are unable to adequately follow the power availability of renewable energy such as wind and solar. Recycling of naphtha can increase the ability of the facility to load balance with the overall utility power supply and can allow for intermittent turndown of electrolyzer units while maintaining a steady supply of syngas feedstock.

[0292] Furthermore, having an additional syngas source may allow for better stability of the Fh:CO ratio (HCR), which is important for maintaining safe Fischer-Tropsch reactor operation, preventing runaway reaction, and preventing catalyst deactivation. Additionally, recycling naphtha into the reforming unit as an additional source of hydrocarbon (besides the tail gas from the Fischer-Tropsch reactor) can help reduce the compositional variability of the tail gas and increase the hydrocarbon content of feed provided to the reforming unit. This would, in turn, increase the operational stability and safety of the reforming unit. Furthermore, integration of naphtha reforming unit into the system can increase the efficiency of the system (in terms of the energetics). For example, such an integration would reduce the amount of CO2 emission relative to the amount of energy used to produce the higher value fuel product (e.g., jet fuel, diesel fuel, etc.).Controller Embodiments

[0293] In embodiments employing a controller or other logic for controlling operation of one or more reactors, pumps, separators, and / or other components of a system the controller or logic may employ program instructions such as executable instructions on computer-readable medium. The instructions may be executed by computer-executable components such as thoseDocket No. OPUSP049WO integrated with a communication system. The computer-readable medium may be stored on any suitable computer-readable media such as RAMs, ROMs, flash memory, EEPROMs, optical devices (CD or DVD), hard drives, floppy drives, or any suitable device. The computerexecutable component is optionally a processor, but the instructions may alternatively or additionally be executed by any suitable dedicated hardware device.

[0294] Although omitted for conciseness, embodiments of the system and / or method can include every combination and permutation of the various system components and the various method processes, wherein one or more instances of the method and / or processes described herein can be performed asynchronously (e.g., sequentially), concurrently (e.g., in parallel), or in any other suitable order by and / or using one or more instances of the systems, elements, and / or entities described herein.

[0295] The Figures illustrate the architecture, functionality and operation of possible implementations of systems, methods and computer program products according to disclosed embodiments, example configurations, and variations thereof. In this regard, each block in the flowchart or block diagrams may represent a module, segment, step, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block can occur out of the order noted in the FIGURES. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and / or flowchart illustration, and combinations of blocks in the block diagrams and / or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

[0296] As a person skilled in the art will recognize from the previous detailed description and from the figures and claims, modifications and changes can be made to the disclosed embodiments of the disclosure without departing from the scope of this disclosure defined in the following claims.

Claims

Docket No. OPUSP049WOCLAIMSWhat is claimed is:

1. A method, comprising: electrochemically reducing carbon dioxide (CO2) to carbon monoxide (CO) using a carbon dioxide reduction electrolyzer; introducing hydrogen gas (H2) and at least a portion of the CO produced by the carbon dioxide reduction electrolyzer to a liquid hydrocarbon synthesis system to produce liquid hydrocarbon products, the liquid hydrocarbon products comprising naphtha and at least one other liquid hydrocarbon product; reforming at least a portion of the naphtha produced by the liquid hydrocarbon synthesis system in a naphtha reforming unit to produce syngas; and introducing at least a portion of the syngas produced by the naphtha reforming unit to the liquid hydrocarbon synthesis system.

2. The method of claim 1, wherein prior to introducing at least a portion of the syngas in the liquid hydrocarbon synthesis system, further comprising introducing the at least a portion of the syngas to a gas purification unit to produce a purified syngas stream.

3. The method of any one of claims 1-2, further comprising producing an exhaust stream comprising CO2 from an external heater associated with the naphtha reforming unit.

4. The method of claim 3, further comprising introducing at least a portion of the CO2 contained within the exhaust stream to a cathode of the carbon dioxide reduction electrolyzer.

5. The method of any one of claims 3-4, further comprising purifying the exhaust stream to produce a purified CO2 stream prior to introducing the purified CO2 stream to the carbon dioxide reduction electrolyzer.

6. The method of any one of claims 2-5, further comprising introducing a cathode product stream comprising CO2, CO, and H2 into the gas purification unit.Docket No. OPUSP049WO7. The method of any one of claims 2-6, further comprising, within the gas purification unit, separating CO2 from syngas to produce a purified CO2 stream and a purified syngas stream.

8. The method of claim 7, further comprising introducing at least a portion of the purified CO2 stream to a cathode inlet of the carbon dioxide reduction electrolyzer.

9. The method of any one of claims 2-8, further comprising introducing at least a portion of the purified syngas stream from the gas purification unit to the liquid hydrocarbon synthesis system.

10. The method of any one of claims 1-9, wherein producing the liquid hydrocarbon products comprises performing a Fischer-Tropsch process to produce a liquid hydrocarbon mixture.

11. The method of claim 10, further comprising subjecting the liquid hydrocarbon mixture to a hydro-processing and / or fractionation process to produce the naphtha and the at least one other liquid hydrocarbon product.

12. The method of any one of claims 1-11, further comprising transporting at least a portion of a tail gas produced by the liquid hydrocarbon synthesis system to the naphtha reforming unit to produce syngas.

13. The method of any one of claims 1-12, wherein at least a portion of the H2 introduced to the liquid hydrocarbon synthesis system is produced by a water electrolyzer.

14. The method of any one of claims 1-13, further comprising introducing steam and / or oxygen (O2) to the naphtha reforming unit.

15. A system, comprising: a carbon dioxide reduction electrolyzer configured to electrochemically reduce carbon dioxide (CO2) to carbon monoxide (CO); a liquid hydrocarbon synthesis system downstream the carbon dioxide reduction electrolyzer and configured to produce liquid hydrocarbon products from hydrogen gas (H2)Docket No. OPUSP049WO and at least a portion of the CO produced by the carbon dioxide reduction electrolyzer, the liquid hydrocarbon products comprising naphtha and at least one other liquid hydrocarbon product; and a naphtha reforming unit downstream the liquid hydrocarbon synthesis system, wherein the naphtha reforming unit is configured to produce syngas from the naphtha produced by the liquid hydrocarbon synthesis system and transport at least a portion of the produced syngas to the liquid hydrocarbon synthesis system.

16. The system of claim 15, wherein the liquid hydrocarbon synthesis system comprises a Fischer-Tropsch reactor.

17. The system of any one of claims 15-16, wherein the liquid hydrocarbon synthesis system comprises a hydro-processing unit and / or fractionation unit downstream the Fischer-Tropsch reactor.

18. The system of any one of claims 15-17, wherein the liquid hydrocarbon synthesis system comprises a reactor inlet configured to receive Fh and CO and a reactor outlet configured to output naphtha.

19. The system of claim 18, wherein the naphtha reforming unit comprises a first reformer inlet fluidically connected to the reactor outlet, the first reformer inlet configured to receive at least a portion of the naphtha from the reactor outlet.

20. The system of any one of claims 18-19, wherein the naphtha reforming unit comprises a first reformer outlet fluidically connected to the reactor inlet, the first reformer outlet configured to output the syngas to the reactor inlet.

21. The system of any one of claims 15-20, wherein the naphtha reforming unit further comprises a second reformer outlet configured to output an exhaust stream containing CO2.

22. The system of claim 21, wherein the second reformer outlet is fluidically connected to a cathode inlet of the carbon dioxide reduction electrolyzer, wherein the carbonDocket No. OPUSP049WO dioxide electrolyzer is configured to accept at least a portion of the CO2 contained within the exhaust stream.

23. The system of any one of claims 15-22, further comprising a gas purification unit positioned between the carbon dioxide reduction electrolyzer and the liquid hydrocarbon synthesis system, wherein the gas purification unit is configured to separate CO2 from syngas to produce a purified CO2 stream and a purified syngas stream.

24. The system of claim 23, wherein the gas purification unit comprises a first inlet fluidically connected to a cathode outlet of the carbon dioxide reduction electrolyzer.

25. The system of any one of claims 20-24, wherein the gas purification unit comprises additional inlet(s) fluidically connected to the first and / or second reformer outlet, wherein the additional inlet(s) is configured to receive the exhaust stream containing CO2 and / or syngas produced by the naphtha reforming unit.

26. The system of any one of claims 23-25, wherein the gas purification unit comprises a first outlet fluidically connected to a cathode inlet of the carbon dioxide reduction electrolyzer, wherein the first outlet is configured to recycle at least a portion of the purified CO2 stream to the cathode inlet.

27. The system of any one of claims 23-26, wherein the gas purification unit comprises a second outlet fluidically connected to the reactor inlet of the liquid hydrocarbon synthesis system, wherein the second outlet is configured to provide at least a portion of the purified syngas stream to the reactor inlet.

28. The system of any preceding claim, further comprising a water electrolyzer configured to produce at least a portion of the hydrogen gas.

29. The method or system of any preceding claim, wherein the carbon dioxide reduction electrolyzer comprises a cathode layer having a reduction catalyst and an ionconducting polymer in contact with a polymer electrolyte membrane for facilitating chemical reduction of the carbon dioxide to carbon monoxide.Docket No. OPUSP049WO30. The method or system of any preceding claim, wherein the naphtha reforming unit comprises one or more of an autothermal reformer, a naphtha steam reformer, and / or a partial oxidation reformer.

31. The method or system of any preceding claim, wherein the naphtha reforming unit comprises an external heater thermally coupled to a naphtha reforming reactor.

32. The method or system of any preceding claim, wherein the external heater comprises a fired heater, an electrical heater, and / or a reformer furnace.

33. The method or system of any preceding claim, wherein the at least one other liquid hydrocarbon product comprises jet fuel.

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