Systems including reactors with two fixed beds and methods of operation

Abstract

Exemplary systems and methods process carbonaceous feeds. Exemplary reactor systems include a reactor comprising two fixed beds: an upper fixed bed and a lower fixed bed. The upper fixed bed may comprise metal oxide particles in an oxidized state and the lower fixed bed may comprise metal oxide particles in a reduced state. Exemplary methods may include operating a reactor system in a first operational mode and a second operational mode. Exemplary first operational modes may include providing fluid carbonaceous feed to a reactor, generating a first gas output, and collecting a first gas output stream. Exemplary second operational modes may include providing an oxidizing gas stream to the reactor, providing an inert gas stream or a reducing gas stream to the reactor, generating a second gas output, and collecting a second gas output stream.

Description

Attorney Docket No. 029784-0014-W001SYSTEMS INCLUDING REACTORS WITH TWO EIXED BEDS AND METHODS OF OPERATIONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 744,081, filed on January 10, 2025, the entire contents of which are incorporated herein by reference.TECHNICAL FIELD

[0002] The instant disclosure relates to systems including reactors with two fixed beds and methods of operating the same.INTRODUCTION

[0003] The global energy landscape is rapidly transforming as demand for low-carbon alternatives grows. Fossil fuels such as coal, oil, and natural gas are depleting, prompting a shift toward non-conventional sources like biomass, biogas, and waste plastics. Combusting these renewable fuels produces heat that can be converted into energy. Although renewable, these fuels remain carbon-based and share characteristics with fossil fuels. Researchers are developing technologies to replace fossil-derived energy with renewables. However, renewable-based systems often face economic challenges that make them less competitive than established fossil fuel technologies.

[0004] One promising approach for efficient energy conversion uses redox-based processes to produce high-purity syngas (a mixture of hydrogen gas (H2) and carbon monoxide (CO)). These processes rely on lattice oxygen from metal oxides, which undergo cyclic oxidation and reduction reactions. Over time, various metal oxide formulations have been optimized for combustion, gasification, and pyrolysis. Reactor systems for these processes typically include two units: a reducer and a combustor. In the reducer, metal oxides oxidize the fuel while being reduced themselves. Depending on the operating mode, the fuel is either fully oxidized to carbon dioxide (CO2) (counter-current mode) or partially oxidized to syngas (co-current mode). The combustor then re-oxidizes the metal oxides using air, completing the cycle. Traditionally, reducers use moving beds, while combustors employ fluidized beds.Attorney Docket No. 029784-0014-W001SUMMARY

[0005] In one aspect, a reactor system is disclosed. An exemplary reactor system may comprise a reactor having an inner volume and comprising: an upper fixed bed comprising metal oxide particles in an oxidized state, the upper fixed bed occupying 10-90 volume percent (vol%) of the inner volume; a lower fixed bed comprising metal oxide particles in a reduced state, the lower fixed bed occupying 10-90 vol% of the inner volume, wherein the upper fixed bed and the lower fixed bed together occupy from 50 vol% to 99 vol% of the inner volume, and a volume ratio of the upper fixed bed to the lower fixed bed is between 1:9 and 9:1; and a separation layer positioned between the upper fixed bed and the lower fixed bed and comprising an inert material, the separation layer occupying 1-50 vol% of the inner volume; a feed inlet in fluid communication with a carbonaceous feedstock source comprising carbonaceous feed, the feed inlet configured to receive carbonaceous feed from the carbonaceous feedstock source and provide the carbonaceous feed to the upper fixed bed; a first gas outlet in fluid communication with the lower fixed bed, the first gas outlet configured to selectively discharge a first gas output stream comprising hydrogen gas (H2) and carbon monoxide (CO); a first gas inlet in fluid communication with a first gas source comprising an oxidizing gas, the first gas inlet configured to selectively provide an oxidizing gas stream to the separation layer; a second gas inlet in fluid communication with a second gas source comprising an inert gas or a reducing gas, the second gas inlet configured to selectively provide an inert gas stream or a reducing gas stream to the lower fixed bed; and a second gas outlet disposed near a top of the upper fixed bed, the second gas outlet configured to selectively discharge a second gas output stream.

[0006] In another aspect, a method of operating a reactor system is disclosed. An exemplary method may comprise operating the reactor system in a first operational mode and a second operational mode, the reactor system comprising a reactor comprising an upper fixed bed comprising metal oxide particles in an oxidized state, a lower fixed bed comprising metal oxide particles in a reduced state, and a separation layer positioned between the upper fixed bed and the lower fixed bed, the method comprising: in the first operational mode: providing fluid carbonaceous feed to a feed inlet of the reactor such that: the fluid carbonaceous feed contacts the metal oxide particles in the upper fixed bed, thereby reducing the metal oxide particles to a lower oxidation state and generating a gaseous product mixture; the gaseous product mixture flows to the lower fixed bed and contacts the metal oxide particles in the reduced state with the gaseousAttorney Docket No. 029784-0014-W001product mixture, thereby generating a first gas output comprising hydrogen gas (H2) and carbon monoxide (CO); and collecting a first gas output stream comprising hydrogen gas (H2) and carbon monoxide (CO) from a first gas outlet of the reactor; and in the second operational mode: providing an oxidizing gas stream to a first gas inlet of the reactor; providing an inert gas stream or a reducing gas stream to a second gas inlet of the reactor, such that: the inert gas stream or the reducing gas stream flows co-currently with the oxidizing gas stream; and the oxidizing gas stream contacts the metal oxide particles at the lower oxidation state, thereby regenerating the metal oxide particles to the oxidized state and generating a second gas output comprising hydrogen gas (H2) and / or carbon monoxide (CO); and collecting a second gas output stream comprising hydrogen gas (H2) and / or carbon monoxide (CO) from a second gas outlet of the reactor.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a schematic depiction of an exemplary reactor system.

[0008] FIG. 2A illustrates a first operational configuration of a first example reactor system. FIG. 2B illustrates a second operational configuration of the first example reactor system.

[0009] FIG. 3 A illustrates a first operational configuration of a second example reactor system. FIG. 3B illustrates a second operational configuration of the second example reactor system.

[0010] FIG. 4A illustrates a first operational configuration of a third example reactor system. FIG. 4B illustrates a second operational configuration of the third example reactor system.

[0011] FIG. 5A illustrates a first operational configuration of a fourth example reactor system. FIG. 5B illustrates a second operational configuration of the fourth example reactor system.

[0012] FIG. 6A illustrates a first operational configuration of a fifth example reactor system. FIG. 6B illustrates a second operational configuration of the fifth example reactor system. FIG.6C illustrates a third operational configuration of the fifth example reactor system.

[0013] FIG. 7 shows the bench-scale experimental setup used for biomass conversion in a ceramic tube reactor, as described in the experimental examples.

[0014] FIG. 8 shows an example gas concentration profile for a biomass gasification redox cycle, based on bench-scale experiments conducted with the setup shown in FIG. 7 and detailed in the experimental examples.

[0015] FIG. 9 presents a graph illustrating syngas purity as a function of temperature, based on bench-scale experiments conducted with the setup shown in FIG. 7 and detailed in theAttorney Docket No. 029784-0014-W001experimental examples.DETAILED DESCRIPTION

[0016] Despite the advantages of redox-based reactor systems comprising a reducer and a combustor that operate using moving and fluidized beds, these systems face technical challenges. Attrition of metal oxide particles reduces efficiency and increases costs. Stability and longevity of metal oxides are compromised in moving and fluidized beds. Handling solid fuels adds logistical complexity, and ash migration can disrupt performance. Fuel composition also varies significantly, affecting reaction dynamics. For example, coal typically contains 40-50% volatile matter, 35-45% char, and 5-20% ash, while biomass has 70-80% volatile matter, 15-20% char, and minimal ash (0-5%). Ash components such as silicates and alkali salts can react with metal oxides, rendering them inactive.

[0017] To address these challenges, the present disclosure provides systems with reactors comprising two fixed beds. The disclosed reactor systems and methods minimize particle attrition, enhance metal oxide stability, and simplify fuel handling while mitigating ash-related issues. Exemplary systems include a reactor comprising two fixed beds: an upper fixed bed and a lower fixed bed. In various implementations, the upper fixed bed comprises metal oxide particles in an oxidized state and the lower fixed bed comprises metal oxide particles in a reduced state.1. Definitions

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document, including definitions, will control. Methods and materials are described below, although methods and materials similar or equivalent to those described herein can be used in practice or testing of the present disclosure. All publications, patent applications, patents and other references mentioned herein are incorporated by reference in their entirety. The materials, methods, and examples disclosed herein are illustrative only and not intended to be limiting.

[0019] The terms “comprise(s),” “include(s),” “having,” “has,” “can,” “contain(s),” and variants thereof, as used herein, are intended to be open-ended transitional phrases, terms, or words that do not preclude the possibility of additional acts or structures. The singular forms “a,” “an” and “the” include plural references unless the context clearly dictates otherwise. The presentAttorney Docket No. 029784-0014-W001disclosure also contemplates other embodiments “comprising,” “consisting of’ and “consisting essentially of,” the embodiments or elements presented herein, whether explicitly set forth or not.

[0020] For the recitation of numeric ranges herein, each intervening number therebetween with the same degree of precision is contemplated. For example, for the range of 6-9, the numbers 7 and 8 are contemplated in addition to 6 and 9, and for the range 6.0-7.0, the numbers 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, and 7.0 are contemplated. For another example, when a pressure range is described as being between ambient pressure and another pressure, a pressure that is ambient pressure is expressly contemplated.

[0021] Definitions of specific functional groups and chemical terms are described in more detail below. For purposes of this disclosure, the chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75thEd., inside cover, and specific functional groups are generally defined as described therein. Additionally, general principles of organic chemistry, as well as specific functional moieties and reactivity, are described in Organic Chemistry, Thomas Sorrell, University Science Books, Sausalito, 1999; Smith and March March's Advanced Organic Chemistry, 5thEdition, John Wiley & Sons, Inc., New York, 2001; Larock, Comprehensive Organic Transformations, VCH Publishers, Inc., New York, 1989; Carruthers, Some Modern Methods of Organic Synthesis, 3rdEdition, Cambridge University Press, Cambridge, 1987; the entire contents of each of which are incorporated herein by reference.IL Exemplary Materials

[0022] Exemplary reactor systems and methods may receive, process, and generate various materials. Exemplary materials may include metal oxide particles, feed materials, separation materials, input gases, and output gases. Various aspects of exemplary metal oxide particles, feed materials, separation materials, input gases, and output gases are described below.A. Exemplary Metal Oxide Particles

[0023] Exemplary systems, methods, and techniques disclosed herein may use various metal oxide particles. Broadly, exemplary reactors described herein include two fixed beds, an upper fixed bed and a lower fixed bed, each containing metal oxide particles. In various implementations, the composition of the metal oxide particles in each fixed bed may be identical or may be distinct. At various times during operation, the oxidation state of the metal oxide particles in each fixed bedAttorney Docket No. 029784-0014-W001may be identical or may be different.

[0024] The metal oxide particles may comprise a metal or a metal oxide having a plurality of oxidation states and may exhibit catalytic activity. As used herein, “catalytic” refers to the ability of metal oxide particles to promote a reaction or transformation under conditions in which the reaction or transformation would not occur in the absence of the metal oxide particles, and wherein the composition of the metal oxide particles does not change.

[0025] Design considerations for exemplary metal oxide particles may include reactivity, recyclability, mechanical strength, and oxygen capacity. Exemplary metal oxide particles may undergo reduction / oxidation reactions that change the oxidation state of one or more species or reactions that change the solid phase of one or more species. Exemplary metal oxide particles may also provide high heat-carrying capacity through the combination of one or more active metal oxides and one or more support metal oxides, thereby maintaining heat balance across the system.

[0026] Aspects of different metal oxide particle compositions and metal oxide particle oxidation states are described below.1. Exemplary Metal Oxide Particle Compositions

[0027] Exemplary metal oxide particles may include one or more active metal oxides. Exemplary metal oxide composites may have at least one of the active metals as iron (Fe). Exemplary metal oxide composites may be a single phase or a mixture of multiple active phases. In various instances, the metal oxide composite comprises more than one active metal capable of undergoing a change in oxidation state under reducing or oxidizing conditions, or a phase change under a partial pressure of carbon dioxide (CO2).

[0028] Other transition metal oxide particles such as nickel oxide (NiO), copper oxide (CuO), cobalt oxide (CoO), and manganese oxide (MnO) may be an active metal oxide in conjunction with iron (Fe). Nickel oxide (NiO), copper oxide (CuO), and other transition metal oxide particles may be particularly suited because of their high oxygen-carrying capacity and good reactivity among all the transition metal oxide candidates. Group I and II metal oxide particles such as magnesium oxide (MgO), calcium oxide (CaO), sodium oxide (Na2O), etc., may also be considered as active metals / metal oxides because of their high affinity towards CO2 through carbonate formation.

[0029] The recyclability of exemplary metal oxide particles may be promoted by adding supportive oxides, also termed support materials, which may also affect the lattice oxygen ionAttorney Docket No. 029784-0014-W001diffusivity. The support material may be any support material known and used in the art. Nonlimiting examples of support materials include, but are not limited to, silica (SiCh), magnesia (MgO), alumina (AI2O3), ceria (CeCh), titania (TiCh), zirconia (ZrCh), or a combination comprising two or more of the aforementioned supports, such as magnesium aluminate spinel (MgAhC ).

[0030] The amount of support material may be 20 wt% to 80 wt% of the metal oxide particle. In various implementations, exemplary metal oxide particles may comprise 20 wt% to 80 wt%; 25 wt% to 75 wt%; 30 wt% to 70 wt%; 35 wt% to 65 wt%; 40 wt% to 60 wt%; 45 wt% to 55 wt%; 50 wt% to 80 wt%; 20 wt% to 50 wt%; 25 wt% to 50 wt%; or 30 wt% to 50 wt% support material. In some instances, the amount of support material may be no greater than 80 wt%; no greater than 75 wt%; no greater than 70 wt%; no greater than 65 wt%; no greater than 60 wt%; no greater than 55 wt%; or no greater than 50 wt%. In some instances, the amount of support material may be no less than 20 wt%; no less than 25 wt%; no less than 30 wt%; no less than 35 wt%; no less than 40 wt%; or no less than 45 wt%.

[0031] Inert carbonate materials such as potassium carbonate (K2CO3) may also be included as a part of the overall composite solid which may later combine with the carbonate phase to form a mixed metal carbonate.

[0032] In some implementations, the reactivity of metal oxide particles may be enhanced by low-concentration dopant modification. One or more dopants may comprise 0 wt% to about 5 wt% of the oxygen carrier particles. In various instances, metal oxide particles may comprise 0 wt% to 5 wt%; 0.5 wt% to 5 wt%; 1 wt% to 5 wt%; 1.5 wt% to 5 wt%; 2 wt% to 5 wt%; 2.5 wt% to 5 wt%; 3 wt% to 5 wt%; 3.5 wt% to 5 wt%; 4 wt% to 5 wt%; 0.5 wt% to 4.5 wt%; 1 wt% to 4 wt%; 1 wt% to 3 wt%; 1 wt% to 2 wt%; 2 wt% to 3 wt%; 2.5 wt% to 3.5 wt%; 3 wt% to 4 wt%; or 4 wt% to 4.5 wt% dopant. In some instances, the dopant concentration may be no greater than 5 wt%; no greater than 4.5 wt%; no greater than 4 wt%; no greater than 3.5 wt%; no greater than 3 wt%; or no greater than 2 wt%. In some instances, the dopant concentration may be no less than 0.5 wt%; no less than 1 wt%; no less than 1.5 wt%; no less than 2 wt%; no less than 2.5 wt%; or no less than 3 wt%.

[0033] Exemplary dopants may have one or more of the following impacts in reactivity enhancement of cyclic chemical looping redox reactions. Exemplary catalytic dopants may provide extra reaction sites during CO2 capture and hydrocarbon conversion in addition to the hostAttorney Docket No. 029784-0014-W001transition metal oxide particles such as iron oxide. The nature of aliovalent dopants, such as Cu2+, Co2+, Ni2+vs Fe3+, may result in an increase of oxygen vacancies, which may promote oxygen ion transport in methane partial oxidation and improve syngas quality. Exemplary catalytic dopants may lower the reaction energy barrier of CO2 capture and C-H activation with the host transition metal oxide particles.

[0034] Example catalytic transition metal dopants include, but are not limited to, nickel (Ni), cobalt (Co), copper (Cu), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), zinc (Zn), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), lutetium (Lu), hafnium (Elf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), and gold (Au).2. Exemplary Metal Oxide Particle Oxidation States

[0035] Metal oxide particles described herein may exhibit a plurality of oxidation states. The oxidation state of exemplary metal oxide particles may serve as an indicator of the solid phases present and the oxygen-carrying capacity of the particles. As used herein, the term “oxygencarrying capacity” refers to the maximum amount of oxygen that metal oxide particles may reversibly store and release during redox cycles under process conditions.

[0036] In some aspects, metal oxide particles may be provided at a first oxidation state and subsequently reduced to a second oxidation state, wherein the second oxidation state is more reduced than the first and has a lower oxygen content. In other aspects, metal oxide particles may be provided at a first oxidation state and subsequently oxidized to a second oxidation state, wherein the second oxidation state is more oxidized than the first and has a higher oxygen content. In further aspects, metal oxide particles may be provided at additional oxidation states, such as a third or fourth oxidation state.

[0037] Metal oxide particles at a lower oxidation state typically have a lower oxygen content, whereas particles at a higher oxidation state typically have a higher oxygen content. As used herein, “higher oxidation state” refers to a more oxidized state, higher oxygen content, or higher oxidation number, and “lower oxidation state” refers to a more reduced state, lower oxygen content, or lower oxidation number.

[0038] Exemplary metal oxide particles may change their oxidation state based on interactions with reducing gases and oxidizing gases. The oxidation state may be defined by equation (1),Attorney Docket No. 029784-0014-W001shown below:. .. . . mass of oxygen lost from metal oxide particle due to reduction „ >_ ... percent solids conversion = - x 100 (1)maximum oxygen loss potential

[0039] As an illustrative example, if an exemplary metal oxide particle comprises ferric oxide (Fe20s) as an active material, the percent reduction of Fe20s may be 0%, FesCh would be 11%, FeO would be 33%, and Fe would be 100%. Accordingly, reducing gases can extract oxygen from the metal oxide particle, increasing the percent solids (%solids) conversion, whereas oxidation decreases the %solids conversion.

[0040] The proposed process schemes may be applied such that metal oxide particles exhibit a %solids conversion value between 0% and 100%. In some instances, the %solids conversion may be 5% to 95%; 10% to 90%; 15% to 85%; 20% to 80%; 25% to 75%; 30% to 70%; 35% to 65%; 40% to 60%; or 45% to 55%. In some instances, the %solids conversion may be no greater than 95%; no greater than 90%; no greater than 85%; no greater than 80%; no greater than 75%; no greater than 70%; no greater than 65%; or no greater than 60%. In some instances, the %solids conversion may be no less than 5%; no less than 10%; no less than 15%; no less than 20%; no less than 25%; no less than 30%; no less than 35%; or no less than 40%. A reactor may increase or decrease the %solids conversion by a value between 0.1% and 99.9%, depending on process conditions, product requirements, and reaction kinetics.

[0041] The composition and / or oxidation state of the metal oxide particles may depend on the specific reactor configuration and / or fixed bed. For example, in various implementations, the reactor includes two fixed beds, wherein one fixed bed contains particles in an oxidized state and the other fixed bed contains particles in a reduced state.

[0042] Exemplary metal oxide particles in an oxidized state may comprise a metal oxide of iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), calcium (Ca), magnesium (Mg), sodium (Na), potassium (K), lithium (Li), strontium (Sr), barium (Ba), titanium (Ti), or a combination thereof. Examples of metal oxide particles in an oxidized state may include calcium ferrite (Ca2Fe2O5), iron (III) oxide (Fe2Ch), manganese (III) oxide (MmCh), cobalt (II, III) oxide (CO3O4), nickel oxide (NiO), and combinations thereof. These oxidized phases have a high lattice oxygen content and function as oxygen donors during reduction reactions. In some aspects, metal oxide particles in an oxidized state may be selected to provide high oxygen-carrying capacity and maintain structural integrity under process conditions. Such particles may also facilitate efficientAttorney Docket No. 029784-0014-W001oxygen transfer during cyclic redox operations.

[0043] Exemplary metal oxide particles in a reduced state may comprise a metal oxide of iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), calcium (Ca), magnesium (Mg), sodium (Na), potassium (K), lithium (Li), strontium (Sr), barium (Ba), titanium (Ti), or a combination thereof. Examples of metal oxide particles in a reduced state may include iron (II) oxide (FeO), manganese (II) oxide (MnO), cobalt (II) oxide (CoO), and combinations thereof.B. Exemplary Separation Layer Materials

[0044] Exemplary reactors described herein further include a separation layer comprising an inert material. The inert material for the separation layer may be selected to provide thermal stability, chemical inertness, and / or mechanical strength under operating conditions.

[0045] In some instances, example separation layer materials may include inert particles. In various implementations, the inert particles may comprise silica (SiCh), magnesia (MgO), quartz, sand, alumina (AI2O3), or a combination thereof.

[0046] In some instances, exemplary separation layers are structures extending across an inner volume of the reactor. In those implementations, exemplary separation layers may be perforated. Perforation size may be such that selected components pass through apertures defined by the separation layer. As a non-limiting example, perforations may be sized to allow gaseous components and small solids, such as ash, to pass through, but not allow metal oxide particles to pass through.C. Exemplary Feed Materials

[0047] Exemplary reactors described herein may be configured to receive and process various feed materials. In some instances, a reactor feed comprises a carbonaceous feed. In some instances, the carbonaceous feed is a fluid carbonaceous feed.

[0048] Exemplary fluid carbonaceous feeds include carbonaceous liquids and carbonaceous gases. Example carbonaceous liquids may include crude oil, gasoline, diesel, glycerol, and combinations thereof. Example carbonaceous gases may include biogas, natural gas, shale gas, gases generated by gasification of a solid fuel, industrial waste gases, and combinations thereof.

[0049] In some implementations, the solid fuel used for gasification may include coal, biomass, petroleum coke, solid waste, plastics, or a combination thereof.Attorney Docket No. 029784-0014-W001D. Exemplary Tnput Gases

[0050] Exemplary reactors described herein may be configured to receive various input gases. The selection of input gases may depend on factors such as reaction requirements, the desired oxidation state of metal oxide particles, and overall process conditions. Example input gases include oxidizing gases, reducing gases, and inert gases.

[0051] As used herein, the term “oxidizing gas” refers to any gaseous species capable of donating or supplying oxygen to a material, thereby increasing its oxidation state. Example oxidizing gases include molecular oxygen (O2), air, steam (H2O), carbon dioxide (CO2), and combinations thereof.

[0052] As used herein, the term “reducing gas” refers to any gaseous species capable of removing oxygen from a material, thereby decreasing its oxidation state. Example reducing gases include hydrogen gas (Eb), carbon monoxide (CO), methane (CH4), and combinations thereof.

[0053] As used herein, the term “inert gas” refers to any gaseous species that does not participate in oxidation or reduction reactions under process conditions. Example inert gases include nitrogen (N2), helium (He), argon (Ar), and combinations thereof.E. Exemplary Output Gases

[0054] In some implementations, the reactor may generate one or more output gases (i.e., gas outputs) during operation. The composition of the output gases may vary based on operating conditions, the oxidation state of the metal oxide particles, the composition of the fluid carbonaceous feed, and the selected input gases.

[0055] Exemplary output gases comprise carbon monoxide (CO) and / or hydrogen gas (H2). In various instances, the output gases comprise syngas (a mixture of H2 and CO).

[0056] Example output gases may contain syngas (CO + H2) in varying amounts. In various instances, each output gas independently comprises at least 80 volume percent (vol%) syngas (CO + H2). In some instances, each output gas independently comprises at least 80 vol%; at least 81 vol%; at least 82 vol%; at least 83 vol%; at least 84 vol%; at least 85 vol%; at least 86 vol%; at least 87 vol%; at least 88 vol%; at least 89 vol%; at least 90 vol%; at least 91 vol%; at least 92 vol%; at least 93 vol%; at least 94 vol%; at least 95 vol%; at least 96 vol%; at least 97 vol%; at least 98 vol%; or at least 99 vol% syngas (CO + H2).

[0057] Exemplary output gases may comprise carbon monoxide (CO) and hydrogen (H2) at various relative amounts. In various instances, each output gas independently comprises CO andAttorney Docket No. 029784-0014-W001H2 at a C0:H2 ratio of from 0 to 5: 1. Tn some instances, each output gas independently comprises CO and TL at a CO:H2ratio of from 0.01:1 to 4.99:1; 0.1:1 to 4.9:1; 0.25:1 to 4.75:1; 0.5:1 to 4.5:1; 0.75:1 to 4.25:1; 1:1 to 4:1; 1.25:1 to 3.75:1; 1.5:1 to 3.5:1; 1.75:1 to 3.25:1; 2:1 to 3:1; or 2.25:1 to 2.75:1. In some instances, each output gas independently comprises CO and H2 at a CO:H2 ratio of no greater than 5 : 1 ; no greater than 4.5:1; no greater than 4:1; no greater than 3.5:1; no greater than 3 : 1 ; no greater than 2.5:1; no greater than 2:1; no greater than 1.5:1; no greater than 1:1; no greater than 0.5:1; or no greater than 0.1:1. In some instances, each output gas independently comprises CO andH2 at a CO:H2 ratio of no less than 0.01:1; no less than 0.1:1; no less than 0.5:1; no less than 1:1; no less than 1.5:1; no less than 2:1; no less than 2.5:1; no less than 3:1; no less than 3.5:1; no less than 4:1; or no less than 4.5:1.

[0058] In some instances, the output gases may further include one or more minor components present at less than 10 vol%. Such minor components may include carbon dioxide (CO2), methane (CH4), and / or nitrogen (N2).III. Exemplary Reactor Systems

[0059] Various reactor systems may be used to perform exemplary methods and techniques described herein. FIG. l is a schematic illustration of an exemplary reactor system 100. As shown, reactor system 100 comprises a carbonaceous feedstock source 102, a reactor 104, a first gas source 106, and a second gas source 108. Optional components are shown in dotted lines. Exemplary optional components may include third gas source 116. Other embodiments may include more or fewer components.

[0060] Reactor system 100 may be configured to process fluid carbonaceous feed and generate product gas. In some instances, reactor system 100 is configured for autothermal operation. Other embodiments may include one or more external heat sources (not shown) to supplement or control the temperature of reactor 104.A. Exemplary System Components

[0061] As shown in FIG. 1, exemplary reactor system 100 comprises a carbonaceous feedstock source 102 in fluid communication with reactor 104. Reactor 104 comprises an upper fixed bed 110, a lower fixed bed 112, and a separation layer 114.

[0062] Upper fixed bed 110 is positioned in an upper (top) portion of reactor 104. Upper fixedAttorney Docket No. 029784-0014-W001bed 110 comprises metal oxide particles in an oxidized state 110A. Exemplary metal oxide particles in an oxidized state are described in greater detail above. The metal oxide particles in the oxidized state 110A are arranged to contact fluid carbonaceous feed received from carbonaceous feedstock source 102 during operation, thereby generating a gaseous product mixture. The gaseous product mixture then flows downward through a separation layer to the lower fixed bed 112.

[0063] In various implementations, the upper fixed bed 110 may occupy 10-90 volume percent (vol%) of an inner volume of reactor 104. In various implementations, upper fixed bed 110 occupies 12 vol% to 88 vol%; 15 vol% to 90 vol%; 20 vol% to 90 vol%; 25 vol% to 90 vol%; 30 vol% to 90 vol%; 35 vol% to 90 vol%; 40 vol% to 90 vol%; 45 vol% to 90 vol%; 50 vol% to 90 vol%; 10 vol% to 80 vol%; 15 vol% to 80 vol%; 20 vol% to 80 vol%; 25 vol% to 80 vol%; 30 vol% to 80 vol%; 35 vol% to 80 vol%; 40 vol% to 80 vol%; 45 vol% to 80 vol%; 50 vol% to 80 vol%; 20 vol% to 70 vol%; 25 vol% to 70 vol%; 30 vol% to 70 vol%; 35 vol% to 70 vol%; 40 vol% to 70 vol%; 45 vol% to 65 vol%; or 55 vol% to 65 vol% of the inner volume of reactor 104.In various implementations, upper fixed bed 110 occupies no less than 10 vol%; no less than 15 vol%; no less than 20 vol%; no less than 25 vol%; no less than 30 vol%; no less than 35 vol%; no less than 40 vol%; no less than 45 vol%; no less than 50 vol%; no less than 55 vol%; no less than 60 vol%; no less than 65 vol%; no less than 70 vol%; no less than 75 vol%; or no less than 80 vol% of the inner volume of reactor 104. In various implementations, upper fixed bed 110 occupies no greater than 90 vol%; no greater than 85 vol%; no greater than 80 vol%; no greater than 75 vol%; no greater than 70 vol%; no greater than 65 vol%; no greater than 60 vol%; no greater than 55 vol%; no greater than 50 vol%; no greater than 45 vol%; no greater than 40 vol%; no greater than 35 vol%; no greater than 30 vol%; no greater than 25 vol%; no greater than 20 vol%; or no greater than 15 vol% of the inner volume of reactor 104.

[0064] Lower fixed bed 112 is positioned in a lower (bottom) portion of reactor 104. Lower fixed bed 112 comprises metal oxide particles in a reduced state 112A. Exemplary metal oxide particles in a reduced state are described in greater detail above. The metal oxide particles in the reduced state 112A are arranged to contact the gaseous product mixture flowing from upper fixed bed 110 during operation, thereby generating a first gas output stream. Exemplary output gases are described in greater detail above.

[0065] In some implementations, the upper fixed bed 110 and the lower fixed bed 112 contain metal oxide particles having the same chemical composition but in different oxidation states. ForAttorney Docket No. 029784-0014-W001example, the upper fixed bed 110 may include iron (ITT) oxide (Fe2C>3)-based metal oxide particles in an oxidized state 110a, and the lower fixed bed 112 may include iron (II) oxide (FeO)-based metal oxide particles in a reduced state 112a.

[0066] In other implementations, the upper fixed bed 110 and the lower fixed bed 112 contain metal oxide particles having distinct chemical compositions, while each bed still maintains its respective oxidation state (oxidized for the upper fixed bed 110 and reduced for the lower fixed bed 112). For example, the upper fixed bed 110 may include iron (III) oxide (Fe2O3)-based metal oxide particles in an oxidized state 110a, and the lower fixed bed 112 may include manganese (II) oxide (MnO)-based metal oxide particles in a reduced state 112a.

[0067] In various implementations, the lower fixed bed 112 may occupy 10-90 vol% of an inner volume of reactor 104. In various implementations, lower fixed bed 112 occupies 12 vol% to 88 vol%; 15 vol% to 90 vol%; 20 vol% to 90 vol%; 25 vol% to 90 vol%; 30 vol% to 90 vol%; 35 vol% to 90 vol%; 40 vol% to 90 vol%; 45 vol% to 90 vol%; 50 vol% to 90 vol%; 10 vol% to 80 vol%; 15 vol% to 80 vol%; 20 vol% to 80 vol%; 25 vol% to 80 vol%; 30 vol% to 80 vol%; 35 vol% to 80 vol%; 40 vol% to 80 vol%; 45 vol% to 80 vol%; 50 vol% to 80 vol%; 20 vol% to 70 vol%; 25 vol% to 70 vol%; 30 vol% to 70 vol%; 35 vol% to 70 vol%; 40 vol% to 70 vol%; 45 vol% to 65 vol%; or 55 vol% to 65 vol% of the inner volume of reactor 104. In various implementations, lower fixed bed 112 occupies no less than 10 vol%; no less than 15 vol%; no less than 20 vol%; no less than 25 vol%; no less than 30 vol%; no less than 35 vol%; no less than 40 vol%; no less than 45 vol%; no less than 50 vol%; no less than 55 vol%; no less than 60 vol%; no less than 65 vol%; no less than 70 vol%; no less than 75 vol%; or no less than 80 vol% of the inner volume of reactor 104. In various implementations, lower fixed bed 112 occupies no greater than 90 vol%; no greater than 85 vol%; no greater than 80 vol%; no greater than 75 vol%; no greater than 70 vol%; no greater than 65 vol%; no greater than 60 vol%; no greater than 55 vol%; no greater than 50 vol%; no greater than 45 vol%; no greater than 40 vol%; no greater than 35 vol%; no greater than 30 vol%; no greater than 25 vol%; no greater than 20 vol%; or no greater than 15 vol% of the inner volume of reactor 104.

[0068] In various implementations, the upper fixed bed 110 and the lower fixed bed 112 together may occupy from 50 vol% to 99 vol% of an inner volume of reactor 104. In various implementations, the combined volume of the upper fixed bed 110 and the lower fixed bed 112 occupies 52 vol% to 99 vol%; 55 vol% to 99 vol%; 60 vol% to 99 vol%; 65 vol% to 99 vol%; 70Attorney Docket No. 029784-0014-W001vol% to 99 vol%; 75 vol% to 99 vol%; 80 vol% to 99 vol%; 85 vol% to 99 vol%; 90 vol% to 99 vol%; 50 vol% to 95 vol%; 55 vol% to 95 vol%; 60 vol% to 95 vol%; 65 vol% to 95 vol%; 70 vol% to 95 vol%; 75 vol% to 95 vol%; 80 vol% to 95 vol%; or 85 vol% to 90 vol% of the inner volume of reactor 104. In various implementations, the combined volume of the upper fixed bed 110 and the lower fixed bed 112 occupies no less than 50 vol%; no less than 55 vol%; no less than 60 vol%; no less than 65 vol%; no less than 70 vol%; no less than 75 vol%; no less than 80 vol%; no less than 85 vol%; or no less than 90 vol% of the inner volume of reactor 104. In various implementations, the combined volume of the upper fixed bed 110 and the lower fixed bed 112 occupies no greater than 99 vol%; no greater than 95 vol%; no greater than 90 vol%; no greater than 85 vol%; no greater than 80 vol%; no greater than 75 vol%; no greater than 70 vol%; no greater than 65 vol%; or no greater than 60 vol% of the inner volume of reactor 104.

[0069] In various implementations, a volume ratio of the upper fixed bed 110 to the lower fixed bed 112 is between 1:9 and 9:1. In various implementations, the volume ratio of the upper fixed bed 110 to the lower fixed bed 112 is 1:8.5 to 8.5:1; 1:8 to 8:1; 1:7 to 7:1; 1:6 to 6:1; 1:5 to 5:1; 1:4 to 4:1; 1:3 to 3:1; 1:2 to 2:1; or 1:1.5 to 1.5:1. In various implementations, the volume ratio of the upper fixed bed 110 to the lower fixed bed 112 is no less than 1:9; no less than 1:8; no less than 1:7; no less than 1:6; no less than 1:5; no less than 1:4; no less than 1:3; no less than 1:2; or no less than 1:1.5. In various implementations, the volume ratio of the upper fixed bed 110 to the lower fixed bed 112 is no greater than 9:1; no greater than 8:1; no greater than 7:1; no greater than 6:1; no greater than 5 : 1 ; no greater than 4: 1 ; no greater than 3:1; or no greater than 2:1.

[0070] Separation layer 114 is positioned between the upper fixed bed 110 and the lower fixed bed 112. Separation layer 114 comprises an inert material. Exemplary inert separation layer materials are described in greater detail above.

[0071] Separation layer 114 is configured to maintain separation between the upper fixed bed 110 and the lower fixed bed 112 while permitting gas flow between the two beds during operation. Exemplary separation layer 114 configurations include a bed of inert particles, a perforated ledge, or a perforated disc.

[0072] In various implementations, the separation layer 114 may occupy 1-50 vol% of an inner volume of reactor 104. In various implementations, separation layer 114 occupies 5 vol% to 50 vol%; 10 vol% to 50 vol%; 15 vol% to 50 vol%; 20 vol% to 50 vol%; 25 vol% to 50 vol%; 30 vol% to 50 vol%; 35 vol% to 50 vol%; 40 vol% to 50 vol%; 45 vol% to 50 vol%; 1 vol% to 45Attorney Docket No. 029784-0014-W001vol%; 1 vol% to 40 vol%; 5 vol% to 40 vol%; 10 vol% to 40 vol%; 15 vol% to 40 vol%; 20 vol% to 40 vol%; 10 vol% to 30 vol%; 15 vol% to 30 vol%; or 20 vol% to 30 vol% of the inner volume of reactor 104. In various implementations, separation layer 114 occupies no less than 1 vol%; no less than 5 vol%; no less than 10 vol%; no less than 15 vol%; no less than 20 vol%; no less than 25 vol%; no less than 30 vol%; no less than 35 vol%; or no less than 40 vol% of the inner volume of reactor 104. In various implementations, separation layer 114 occupies no greater than 50 vol%; no greater than 45 vol%; no greater than 40 vol%; no greater than 35 vol%; no greater than 30 vol%; no greater than 25 vol%; no greater than 20 vol%; no greater than 15 vol%; no greater than 10 vol%; or no greater than 5 vol% of the inner volume of reactor 104.

[0073] Carbonaceous feedstock source 102 is configured to provide carbonaceous feed to a feed inlet of reactor 104 (not shown). The feed inlet of reactor 104 is configured to receive carbonaceous feed from the carbonaceous feedstock source 102 and provide the carbonaceous feed to the upper fixed bed 110. Exemplary carbonaceous feeds are discussed in greater detail above.

[0074] In some implementations, reactor 104 may comprise a plurality of feed inlets arranged vertically along a side of the reactor, shown schematically in dashed lines in FIG. 1. In some implementations, the plurality of feed inlets may be configured receive fluid carbonaceous feed simultaneously to allow distributed contact with the metal oxide particles. In other implementations, the plurality of feed inlets may be configured to receive fluid carbonaceous feed sequentially for staged injection along the upper fixed bed.

[0075] In some implementations, carbonaceous feedstock source 102 comprises a gasifier. When present, the gasifier is configured to receive solid fuel, generate a carbonaceous gas and solid byproducts, separate the solid byproducts from the carbonaceous gas, and provide the carbonaceous gas to a feed inlet of the reactor 104.

[0076] Exemplary gasifiers comprise a solid fuel inlet, a carbonaceous gas outlet, and a solid byproducts outlet. The solid fuel inlet is in fluid communication with a solid carbonaceous feedstock source and is configured to receive solid fuel. Exemplary solid fuels are described in greater detail above. The carbonaceous gas outlet is in fluid communication with a feed inlet of the reactor 104 and is configured to provide a carbonaceous gas stream to the feed inlet. The solid byproducts outlet is configured to discharge solid byproducts. Exemplary solid byproducts may comprise ash and / or char.

[0077] Exemplary reactor system 100 further comprises a first gas source 106 in fluidAttorney Docket No. 029784-0014-W001communication with reactor 104. The first gas source 106 is configured to selectively provide an oxidizing gas stream to the separation layer 114. Exemplary oxidizing gases are described in greater detail above. Upon being provided to the separation layer 114, the oxidizing gas flows upward toward the upper fixed bed 110.

[0078] In various implementations, a first gas inlet is disposed near a side of separation layer 114 and is in fluid communication with the first gas source 106. The first gas inlet is configured to selectively provide an oxidizing gas stream from the first gas source 106 to the separation layer 114

[0079] Exemplary reactor system 100 further comprises a second gas source 108 in fluid communication with reactor 104. The second gas source 108 is configured to selectively provide an inert gas stream or a reducing gas stream to lower fixed bed 112. Exemplary inert gases and reducing gases are described in greater detail above.

[0080] In various implementations, a second gas inlet is positioned near a bottom portion of the reactor 104 and is in fluid communication with the second gas source 108. The second gas inlet is configured to selectively provide an inert gas stream or a reducing gas stream to the lower fixed bed 112.

[0081] In various implementations, a first gas outlet is positioned near a bottom portion of the reactor 104 and is in fluid communication with the lower fixed bed 112. The first gas outlet is configured to selectively discharge a first gas output stream.

[0082] In various implementations, a second gas outlet is disposed near a top of the upper fixed bed 110. The second gas outlet is configured to selectively discharge a second gas output stream.

[0083] In some implementations, the second gas outlet is in fluid communication with the second gas inlet and is configured to circulate the second gas output stream to the second gas inlet such that the second gas output stream is used as the reducing gas stream.

[0084] In some implementations, reactor system 100 further includes an optional third gas source 116 in fluid communication with reactor 104. When present, optional third gas source 116 is positioned on an opposite side of reactor 104 from first gas source 106. When present, optional third gas source 116 is configured to selectively provide an additional oxidizing gas stream to separation layer 114.B. Exemplary System Configurations

[0085] Exemplary reactor system 100 may be implemented in various configurations. VariousAttorney Docket No. 029784-0014-W001aspects of exemplary system configurations are discussed below with reference to FIGS. 2A-6C. Although the reactors shown in FIGS. 2A-6C schematically depict a larger upper fixed bed relative to the lower fixed bed, configurations having a larger lower fixed bed than the upper fixed bed are also contemplated.

[0086] FIGS. 2A-2B illustrate a first example reactor system, which, during typical operation, is configured to cycle between the operational configuration shown in FIG. 2A and the operational configuration shown in FIG. 2B. As shown in FIG. 2A, the first example reactor system includes a reactor in fluid communication with a gasifier. The reactor comprises an upper fixed bed, a lower fixed bed, and a separation layer. The gasifier is configured to receive solid fuel, generate a carbonaceous gas and solid byproducts, separate the solid byproducts from the carbonaceous gas, and provide the carbonaceous gas to a feed inlet of the reactor.

[0087] In the first operational configuration, shown in FIG. 2A, carbonaceous gas is provided to the upper fixed bed through the feed inlet of the reactor, whereupon the metal oxide particles in the oxidized state are reduced and a gaseous product mixture is generated. The gaseous product mixture flows to the lower fixed bed, where it contacts the metal oxide particles in the reduced state, thereby generating a first gas output stream.

[0088] In the second operational configuration, shown in FIG. 2B, an oxidizing gas stream is provided to the separation layer and flows upward through the upper fixed bed, thereby regenerating the metal oxide particles to the oxidized state and generating a second gas output stream. Simultaneously, an inert gas stream or a reducing gas stream is provided to the lower fixed bed and flows co-currently with the oxidizing gas stream.

[0089] FIGS. 3A-3B illustrate a second example reactor system, which, during typical operation, is configured to cycle between the two operational configurations shown. The second example reactor system is the same as the first example reactor system (FIGS. 2A-2B), except that the second example reactor system includes a plurality of feed inlets positioned vertically along a side of the reactor.

[0090] In the first operational configuration (FIG. 3A), carbonaceous gas is provided through the plurality of feed inlets, contacting metal oxide particles in the oxidized state at different vertical locations along the upper fixed bed, whereupon the metal oxide particles in the oxidized state are reduced and a gaseous product mixture is generated. The gaseous product mixture flows to the lower fixed bed, where it contacts the metal oxide particles in the reduced state, thereby generatingAttorney Docket No. 029784-0014-W001a first gas output stream.

[0091] In the second operational configuration (FIG. 3B), an oxidizing gas stream is provided to the separation layer and flows upward through the upper fixed bed, thereby regenerating the metal oxide particles to the oxidized state and generating a second gas output stream. Simultaneously, an inert gas stream or a reducing gas stream is provided to the lower fixed bed and flows co-currently with the oxidizing gas stream.

[0092] FIGS. 4A-4B illustrate a third example reactor system, which, during typical operation, is configured to cycle between the two operational configurations shown. The third example reactor system is the same as the first example reactor system (FIGS. 2A-2B), except that the second gas output stream is recycled to a second gas inlet, where the second gas output stream serves as the reducing gas stream.

[0093] In the first operational configuration (FIG. 4A), carbonaceous gas is provided to the upper fixed bed through a feed inlet of the reactor, whereupon the metal oxide particles in the oxidized state are reduced and a gaseous product mixture is generated. The gaseous product mixture flows to the lower fixed bed, where it contacts the metal oxide particles in the reduced state, thereby generating a first gas output stream. In the second operational configuration (FIG.4B), an oxidizing gas stream is provided to the separation layer and flows upward through the upper fixed bed, thereby regenerating the metal oxide particles to the oxidized state and generating a second gas output stream. The second gas output stream is recycled to the second gas inlet, such that the second gas output stream serves as a reducing gas stream that flows co-currently with the oxidizing gas stream.

[0094] FIGS. 5A-5B illustrate a fourth example reactor system, which, during typical operation, is configured to cycle between the two operational configurations shown. The fourth example reactor system is the same as the third example reactor system (FIGS. 4A-4B), except that the fourth example reactor system includes a plurality of feed inlets positioned vertically along a side of the reactor.

[0095] In the first operational configuration (FIG. 5A), carbonaceous gas is provided through the plurality of feed inlets, contacting metal oxide particles in the oxidized state at different vertical locations along the upper fixed bed, whereupon the metal oxide particles in the oxidized state are reduced and a gaseous product mixture is generated. The gaseous product mixture flows to the lower fixed bed, where it contacts the metal oxide particles in the reduced state, thereby generatingAttorney Docket No. 029784-0014-W001a first gas output stream.

[0096] In the second operational configuration, shown in FIG. 5B, an oxidizing gas stream is provided to the separation layer and flows upward through the upper fixed bed, thereby regenerating the metal oxide particles to the oxidized state and generating a second gas output stream. The second gas output stream is recycled to the second gas inlet, such that the second gas output stream serves as a reducing gas stream that flows co-currently with the oxidizing gas stream.

[0097] FIGS. 6A-6C illustrate a fifth example reactor system, which, during typical operation, is configured to cycle among the three operational configurations shown. The fifth example reactor system is the same as the fourth example reactor system (FIGS. 5A-5B), except that FIG. 6B and FIG. 6C, which correspond to the second operational configuration, illustrate variations in the second gas output stream based on the oxidizing gas employed. For example, when steam (H2O) is used as oxidizing gas, the second gas output stream may be enriched in hydrogen (H2). In contrast, when carbon dioxide (CO2) is used as the oxidizing gas, the second gas output stream may comprise a higher proportion of carbon monoxide (CO).IV. Exemplary Methods of Operation

[0098] Various methods may be employed to operate exemplary reactor systems contemplated herein. Broadly, example methods may comprise operating a reactor system in a first operational mode and a second operational mode. Exemplary reactor systems and materials described above may be used to implement one or more of the methods described below. Other embodiments may include more or fewer operations than those discussed below.A. Exemplary First Operational Modes

[0099] Operating a reactor system in a first operational mode may begin by providing fluid carbonaceous feed to a feed inlet of the reactor. The fluid carbonaceous feed may be provided such that it contacts the metal oxide particles in the upper fixed bed, thereby reducing the metal oxide particles to a lower oxidation state and generating a gaseous product mixture.

[0100] Exemplary fluid carbonaceous feeds are described in greater detail above. In some implementations, the fluid carbonaceous feed may be generated by a gasifier. A solid fuel may be received into the gasifier. Within the gasifier, the solid fuel may be converted to generate a carbonaceous gas and solid byproducts. The carbonaceous gas may then be separated from the solid byproducts and provided to the feed inlet of the reactor.Attorney Docket No. 029784-0014-W001

[0101] After providing the fluid carbonaceous feed to the reactor, the gaseous product mixture may flow to the lower fixed bed. Upon flowing to the lower fixed bed, the gaseous product mixture may contact the metal oxide particles in the reduced state, thereby generating a first gas output comprising hydrogen gas (H2) and carbon monoxide (CO).

[0102] Exemplary methods may further comprise collecting a first gas output stream from a first gas outlet of the reactor. The first gas output stream may comprise hydrogen gas (H2) and carbon monoxide (CO). The composition of the first gas output stream may depend on the carbonaceous feed composition. For example, feeds with higher hydrogen content may produce a first output gas stream having a greater proportion of hydrogen gas (H2), whereas feeds with higher carbon content may produce a first output gas stream having a greater proportion of carbon monoxide (CO). In various instances, the first gas output stream may comprise at least 80 vol% combined CO and H2. Exemplary output gases are described in greater detail above.

[0103] In various instances, operating a reactor system in a first operational mode may further comprise maintaining the reactor at a temperature of 300 °C to 1200 °C. In various instances, operating a reactor system in a first operational mode may comprise maintaining the reactor at a temperature of 350 °C to 1150 °C; 400 °C to 1100 °C; 450 °C to 1050 °C; 500 °C to 1000 °C; 550 °C to 950 °C; 600 °C to 900 °C; 650 °C to 850 °C; 700 °C to 800 °C; or 750 °C to 775 °C. In various instances, operating a reactor system in a first operational mode may comprise maintaining the reactor at a temperature of no greater than 1200 °C; no greater than 1100 °C; no greater than 1000 °C; no greater than 900 °C; no greater than 800 °C; no greater than 700 °C; no greater than 600 °C; no greater than 500 °C; or no greater than 400 °C. In various instances, operating a reactor system in a first operational mode may comprise maintaining the reactor at a temperature of no less than 300 °C; no less than 400 °C; no less than 500 °C; no less than 600 °C; no less than 700 °C; no less than 800 °C; no less than 900 °C; no less than 1000 °C; or no less than 1100 °C.

[0104] In various instances, operating a reactor system in a first operational mode may further comprise maintaining the reactor at a pressure of 0.1 MPa to 3 MPa. In some instances, operating a reactor system in a first operational mode may comprise maintaining the reactor at a pressure of 0.25 MPa to 2.75 MPa; 0.5 MPa to 2.5 MPa; 0.75 MPa to 2.25 MPa; 1 MPa to 2 MPa; 1.25 MPa to 1.75 MPa; or 1.25 MPa to 1.5 MPa. In some instances, operating a reactor system in a first operational mode may comprise maintaining the reactor at a pressure of no greater than 3 MPa; no greater than 2.75 MPa; no greater than 2.5 MPa; no greater than 2.25 MPa; no greater than 2 MPa;Attorney Docket No. 029784-0014-W001no greater than 1.75 MPa; no greater than 1.5 MPa; no greater than 1 MPa; or no greater than 0.5 MPa. In some instances, operating a reactor system in a first operational mode may comprise maintaining the reactor at a pressure of no less than 0.1 MPa; no less than 0.25 MPa; no less than 0.5 MPa; no less than 0.75 MPa; no less than 1 MPa; no less than 1.25 MPa; no less than 1.5 MPa; no less than 2 MPa; no less than 2.25 MPa; or no less than 2.5 MPa.

[0105] During the first operational mode, the fluid carbonaceous feed residence time in the reactor may vary. As used herein, the term “residence time” refers to the average duration that a fluid stream (e.g., carbonaceous feed, oxidizing gas, inert gas, or reducing gas) remains within the reactor’s inner volume under operating conditions before exiting through a designated outlet. Residence time is determined based on the effective reactor volume available for fluid flow and the volumetric flow rate of the stream at operating temperature and pressure. Mathematically, residence time (T) can be expressed as:

[0106] “ ^effective,” i.e., the effective reactor volume, refers to the portion of the reactor’s inner volume in which the stream contacts the fixed beds comprising metal oxide particles, “^operating,” i.e., “the operating volumetric flow rate” refers to the volumetric flow rate of the stream under reactor operating conditions, accounting for temperature and pressure.

[0107] In some instances, a fluid carbonaceous feed residence time in the reactor is 1 second to 10 seconds. In some instances, the fluid carbonaceous feed residence time in the reactor may be 1.25 seconds to 9 seconds; 1.5 seconds to 8 seconds; 1.75 seconds to 7.5 seconds; 2 seconds to 5 seconds; 2.25 seconds to 5.5 seconds; 2.5 seconds to 6 seconds; 2.75 seconds to 5.75 seconds; 3 seconds to 5.5 seconds; 3.25 seconds to 5.25 seconds; 3.5 seconds to 5 seconds; 3.75 seconds to 4.75 seconds; or 4 seconds to 4.5 seconds. In some instances, the fluid carbonaceous feed residence time in the reactor may be no greater than 10 seconds; no greater than 9 seconds; no greater than 8 seconds; no greater than 7.5 seconds; no greater than 7 seconds; no greater than 6.5 seconds; no greater than 6 seconds; no greater than 5.5 seconds; no greater than 5 seconds; no greater than 4.5 seconds; no greater than 4 seconds; no greater than 3.5 seconds; no greater than 3 seconds; no greater than 2.5 seconds; or no greater than 2 seconds. In some instances, the fluid carbonaceous feed residence time in the reactor may be no less than 1 second; no less than 1.25 seconds; no lessAttorney Docket No. 029784-0014-W001than 1.5 seconds; no less than 1.75 seconds; no less than 2 seconds; no less than 2.25 seconds; no less than 2.5 seconds; no less than 2.75 seconds; no less than 3 seconds; no less than 3.5 seconds; no less than 4 seconds; no less than 4.5 seconds; no less than 5 seconds; no less than 5.5 seconds; no less than 6 seconds; no less than 6.5 seconds; or no less than 7 seconds.

[0108] In various implementations, the reactor system may employ various criteria to determine when to transition from the first operational mode to the second operational mode.

[0109] The transition from the first operational mode to the second operational mode may be initiated when the concentration of a target chemical in the first output stream falls below a predetermined threshold, or when the oxidation state of the metal oxide particles in the upper fixed bed reaches a specified lower limit. In various implementations, the reactor system may monitor the composition of the first gas output stream, such as measuring hydrogen gas (H2) and / or carbon monoxide (CO) concentrations, or evaluate the reduction level of the metal oxide particles. Based on these monitored parameters, the system may switch to the second operational mode to regenerate the metal oxide particles to their oxidized state.

[0110] In some implementations, the transition from the first operational mode to the second operational mode may be initiated when the %solids conversion of the metal oxide particles in the upper fixed bed reaches a predetermined lower threshold. As described in greater detail above, %solids conversion refers to the proportion of oxygen lost from the metal oxide particles due to reduction, relative to their maximum oxygen loss potential. The reactor system may monitor the %solids conversion directly, or calculate the %solids conversion from the composition of the first gas output stream (e.g., concentrations of Fhand CO). When the %solids conversion indicates that the metal oxide particles have been sufficiently reduced, such as reaching a lower limit of 60% or another selected value, the system may switch to the second operational mode to regenerate the metal oxide particles to the oxidized state.B. Exemplary Second Operational Modes

[0111] Operating a reactor system in a second operational mode may begin by providing an oxidizing gas stream to a first gas inlet of the reactor. The oxidizing gas stream may be selectively provided to the separation layer from a first gas source comprising an oxidizing gas. Exemplary oxidizing gases are described in greater detail above.

[0112] While providing an oxidizing gas stream to the first gas inlet of the reactor, the methodAttorney Docket No. 029784-0014-W001may further comprise providing an inert gas stream or a reducing gas stream to a second gas inlet of the reactor. The inert gas stream or reducing gas stream may be selectively provided to the lower fixed bed from a second gas source comprising an inert gas or a reducing gas. Exemplary inert gases and reducing gases are described in greater detail above. The inert gas stream or reducing gas stream may be provided to the second gas inlet of the reactor such that the inert gas stream or the reducing gas stream flows co-currently with the oxidizing gas stream and the oxidizing gas stream contacts the metal oxide particles at the lower oxidation state, thereby regenerating the metal oxide particles to the oxidized state and generating a second gas output comprising hydrogen gas (H2) and / or carbon monoxide (CO).

[0113] Operating a reactor system in a second operational mode may further comprise collecting a second gas output stream from a second gas outlet of the reactor. The second gas output stream may comprise hydrogen gas (H2) and / or carbon monoxide (CO). In various instances, the first gas output stream may comprise at least 80 vol% combined CO and H2. The composition of the second gas output stream may depend on the oxidizing gas introduced during operation. For example, when steam (H2O) is used as the oxidizing gas, the second gas output stream may include a higher proportion of hydrogen gas (H2), whereas when carbon dioxide (CO2) is used as the oxidizing gas, the second gas output stream may include a higher proportion of carbon monoxide (CO). Exemplary output gases are described in greater detail above.

[0114] In some implementations, the second gas output stream may be recycled to the second gas inlet of the reactor such that the second gas output stream is used as the reducing gas stream.

[0115] In various instances, operating a reactor system in a second operational mode may further comprise maintaining the reactor at a temperature of 300 °C to 1200 °C. In various instances, operating a reactor system in a second operational mode may further comprise maintaining the reactor at a temperature of 350 °C to 1150 °C; 400 °C to 1100 °C; 450 °C to 1050 °C; 500 °C to 1000 °C; 550 °C to 950 °C; 600 °C to 900 °C; 650 °C to 850 °C; 700 °C to 800 °C; or 750 °C to 775 °C. In various instances, operating a reactor system in a second operational mode may further comprise maintaining the reactor at a temperature of no greater than 1200 °C; no greater than 1100 °C; no greater than 1000 °C; no greater than 900 °C; no greater than 800 °C; no greater than 700 °C; no greater than 600 °C; no greater than 500 °C; or no greater than 400 °C. In various instances, operating a reactor system in a second operational mode may further comprise maintaining the reactor at a temperature of no less than 300 °C; no less than 400 °C; noAttorney Docket No. 029784-0014-W001less than 500 °C; no less than 600 °C; no less than 700 °C; no less than 800 °C; no less than 900 °C; no less than 1000 °C; or no less than 1100 °C.

[0116] In various instances, operating a reactor system in a second operational mode may further comprise maintaining the reactor at a pressure of 0.1 MPa to 3 MPa. In some instances, operating a reactor system in a second operational mode may comprise maintaining the reactor at a pressure of 0.25 MPa to 2.75 MPa; 0.5 MPa to 2.5 MPa; 0.75 MPa to 2.25 MPa; 1 MPa to 2 MPa; 1.25 MPa to 1.75 MPa; or 1.25 MPa to 1.5 MPa. In some instances, operating a reactor system in a second operational mode may comprise maintaining the reactor at a pressure of no greater than 3 MPa; no greater than 2.75 MPa; no greater than 2.5 MPa; no greater than 2.25 MPa; no greater than 2 MPa; no greater than 1.75 MPa; no greater than 1.5 MPa; no greater than 1 MPa; or no greater than 0.5 MPa. In some instances, operating a reactor system in a second operational mode may comprise maintaining the reactor at a pressure of no less than 0.1 MPa; no less than 0.25 MPa; no less than 0.5 MPa; no less than 0.75 MPa; no less than 1 MPa; no less than 1.25 MPa; no less than 1.5 MPa; no less than 2 MPa; no less than 2.25 MPa; or no less than 2.5 MPa.

[0117] During the second operational mode, the oxidizing gas residence time in the reactor may vary. Exemplary methods for calculating residence time are described in greater detail above. In some instances, an oxidizing gas residence time in the reactor is 1 second to 10 seconds. In some instances, the oxidizing gas residence time in the reactor may be 1.25 seconds to 9 seconds; 1.5 seconds to 8 seconds; 1.75 seconds to 7.5 seconds; 2 seconds to 5 seconds; 2.25 seconds to 5.5 seconds; 2.5 seconds to 6 seconds; 2.75 seconds to 5.75 seconds; 3 seconds to 5.5 seconds; 3.25 seconds to 5.25 seconds; 3.5 seconds to 5 seconds; 3.75 seconds to 4.75 seconds; or 4 seconds to 4.5 seconds. In some instances, the oxidizing gas residence time in the reactor may be no greater than 10 seconds; no greater than 9 seconds; no greater than 8 seconds; no greater than 7.5 seconds; no greater than 7 seconds; no greater than 6.5 seconds; no greater than 6 seconds; no greater than 5.5 seconds; no greater than 5 seconds; no greater than 4.5 seconds; no greater than 4 seconds; no greater than 3.5 seconds; no greater than 3 seconds; no greater than 2.5 seconds; or no greater than 2 seconds. In some instances, the oxidizing gas residence time in the reactor may be no less than 1 second; no less than 1.25 seconds; no less than 1.5 seconds; no less than 1.75 seconds; no less than 2 seconds; no less than 2.25 seconds; no less than 2.5 seconds; no less than 2.75 seconds; no less than 3 seconds; no less than 3.5 seconds; no less than 4 seconds; no less than 4.5 seconds; no less than 5 seconds; no less than 5.5 seconds; no less than 6 seconds; no less than 6.5 seconds; orAttorney Docket No. 029784-0014-W001no less than 7 seconds.

[0118] In various implementations, the reactor system may employ various criteria to determine when to transition from the second operational mode back to the first operational mode.

[0119] The transition from the second operational mode to the first operational mode may be initiated when the concentration of a target chemical in the second output stream exceeds a predetermined threshold, or when the oxidation state of the metal oxide particles in the upper fixed bed reaches a specified upper limit. In various implementations, the reactor system may monitor the composition of the second gas output stream, such as measuring hydrogen gas (H2) and / or carbon monoxide (CO) concentrations, or evaluate the oxidation level of the metal oxide particles. Based on these monitored parameters, the system may switch to the first operational mode to resume conversion of carbonaceous feed.

[0120] In some implementations, transition from the second operational mode to the first operational mode may be initiated when the %solids conversion of the metal oxide particles in the upper fixed bed returns to a predetermined upper threshold. The reactor system may monitor the %solids conversion directly, or calculate the %solids conversion from the composition of the second gas output stream (e g., concentrations of H2 and CO). When the %solids conversion indicates that the metal oxide particles have been sufficiently regenerated, such as reaching an upper limit of 100% or another selected value, the system may switch to the first operational mode to continue conversion of carbonaceous feed.V. Experimental Examples

[0121] Various experimental examples were conducted and the results are discussed below.

[0122] The experiments were carried out in a dual-bed fixed bed ceramic tube reactor with an outer diameter (OD) of 1 inch and an inner diameter (ID) of 0.75 inch. The experimental setup is shown in FIG. 7. The reactor was heated to target temperatures of 800 °C, 900 °C, and 1000 °C at atmospheric pressure using a tube furnace with a ramp rate of 20°C / min. The carbonaceous feedstock (biomass feedstock) consisted of hardwood pellets milled to a size range of 1.7-2.32 mm. These pellets were provided into the reactor through a lock hopper system designed to prevent air contact by continuously purging nitrogen (N2). The N2 purge flow through the lock hopper was maintained at 50 mL / min, while an additional N2 flow of 100 mL / min was supplied through the top of the reactor along with water at 0.01 mL / min, delivered by a syringe pump for charAttorney Docket No. 029784-0014-W001conversion.

[0123] The gases exiting the reactor were diluted with 500 mL / min of N2 and passed through a desiccant column for moisture removal. The product gases were then analyzed using two gas analyzers, Calomat and Ultramat 23, connected in series. Ultramat 23 measured carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and oxygen (O2), while Calomat quantified hydrogen gas (H2). An example gas concentration profile for a biomass gasification redox cycle is shown in FIG. 8. The biomass feedstock was provided in multiple batches of 0.2 g each at 2-minute intervals. Upon entering the reactor, the pellets were pyrolyzed at high temperature, releasing volatiles that reacted with the metal oxide material to produce syngas.

[0124] For dual -bed fixed bed experiments, a bed of metal oxide particles in a reduced state (i.e., the lower fixed bed) was placed at the bottom of the reactor, topped with the oxidized bed (i.e., the upper fixed bed), separated by a quartz layer (i.e., the separation layer). In both configurations, the loading of metal oxide particles in an oxidized state was maintained at 30 g. The lower fixed bed maintained thermodynamic equilibrium between the outlet gases and the metal oxide particles, mimicking a co-current moving bed system. The results are shown in FIG.9.Exemplary Embodiments

[0125] For reasons of completeness, various aspects of the technology are set out in the following numbered embodiments.Embodiment 1. A reactor system, comprising:a reactor having an inner volume and comprising:an upper fixed bed comprising metal oxide particles in an oxidized state, the upper fixed bed occupying 10-90 volume percent (vol%) of the inner volume;a lower fixed bed comprising metal oxide particles in a reduced state, the lower fixed bed occupying 10-90 vol% of the inner volume,wherein the upper fixed bed and the lower fixed bed together occupy from 50 vol% to 99 vol% of the inner volume, and a volume ratio of the upper fixed bed to the lower fixed bed is between 1 :9 and 9:1; andAttorney Docket No. 029784-0014-W001a separation layer positioned between the upper fixed bed and the lower fixed bed and comprising an inert material, the separation layer occupying 1-50 vol% of the inner volume;a feed inlet in fluid communication with a carbonaceous feedstock source comprising carbonaceous feed, the feed inlet configured to receive carbonaceous feed from the carbonaceous feedstock source and provide the carbonaceous feed to the upper fixed bed;a first gas outlet in fluid communication with the lower fixed bed, the first gas outlet configured to selectively discharge a first gas output stream comprising hydrogen gas (H2) and carbon monoxide (CO);a first gas inlet in fluid communication with a first gas source comprising an oxidizing gas, the first gas inlet configured to selectively provide an oxidizing gas stream to the separation layer;a second gas inlet in fluid communication with a second gas source comprising an inert gas or a reducing gas, the second gas inlet configured to selectively provide an inert gas stream or a reducing gas stream to the lower fixed bed; anda second gas outlet disposed near a top of the upper fixed bed, the second gas outlet configured to selectively discharge a second gas output stream.Embodiment 2. The reactor system according to embodiment 1, wherein the second gas outlet is in fluid communication with the second gas inlet, the second gas outlet configured to circulate the second gas output stream to the first gas inlet such that the second gas output stream is used as the reducing gas stream.Embodiment 3. The reactor system according to embodiment 1 or 2, the reactor comprising a plurality of feed inlets arranged vertically along a side of the reactor.Embodiment 4. The reactor system according to any one of embodiments 1-3, wherein the carbonaceous feedstock source is a gasifier configured to:receive solid fuel;generate a carbonaceous gas and solid byproducts;Attorney Docket No. 029784-0014-W001separate the solid byproducts from the carbonaceous gas; andprovide the carbonaceous gas to the feed inlet of the reactor.Embodiment 5. The reactor system according to embodiment 4, wherein the gasifier comprises:a solid fuel inlet configured to receive solid fuel, the solid fuel inlet being in fluid communication with a solid carbonaceous feedstock source;a carbonaceous gas outlet in fluid communication with the feed inlet of the reactor, the carbonaceous gas outlet configured to provide a carbonaceous gas stream to the feed inlet; anda solid byproducts outlet configured to discharge solid byproducts, the solid byproducts comprising ash and / or char.Embodiment 6. The reactor system according to embodiment 4 or 5, wherein the solid fuel comprises coal, biomass, petroleum coke, solid waste, and / or plastics.Embodiment 7. The reactor system according to any one of embodiments 1-6, wherein the metal oxide particles in the oxidized state and the metal oxide particles in the reduced state each independently comprise a metal oxide of iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), calcium (Ca), magnesium (Mg), sodium (Na), potassium (K), lithium (Li), strontium (Sr), barium (Ba), titanium (Ti), or a combination thereof.Embodiment 8. The reactor system according to any one of embodiments 1-7, wherein the metal oxide particles in the oxidized state comprise calcium ferrite (Ca2Fe20s), iron (III) oxide (Fe20s), manganese (III) oxide (M Ch), cobalt (II, III) oxide (CO3O4), or a combination thereof.Embodiment 9. The reactor system according to any one of embodiments 1-8, wherein the metal oxide particles in the reduced state comprise iron (II) oxide (FeO), manganese (II) oxide (MnO), cobalt (II) oxide (CoO), or a combination thereof.Attorney Docket No. 029784-0014-W001Embodiment 10. The reactor system according to any one of embodiments 1-9, wherein the separation layer is a bed of inert particles, a perforated ledge, or a perforated disc.Embodiment 11. The reactor system according to embodiment 10, wherein the inert particles comprise silica (SiCh), magnesia (MgO), quartz, sand, alumina (AI2O3), or a combination thereof.Embodiment 12. A method of operating a reactor system in a first operational mode and a second operational mode, the reactor system comprising a reactor comprising an upper fixed bed comprising metal oxide particles in an oxidized state, a lower fixed bed comprising metal oxide particles in a reduced state, and a separation layer positioned between the upper fixed bed and the lower fixed bed, the method comprising:in the first operational mode:providing fluid carbonaceous feed to a feed inlet of the reactor such that:the fluid carbonaceous feed contacts the metal oxide particles in the upper fixed bed, thereby reducing the metal oxide particles to a lower oxidation state and generating a gaseous product mixture;the gaseous product mixture flows to the lower fixed bed and contacts the metal oxide particles in the reduced state with the gaseous product mixture, thereby generating a first gas output comprising hydrogen gas (H2) and carbon monoxide (CO); andcollecting a first gas output stream comprising hydrogen gas (H2) and carbon monoxide (CO) from a first gas outlet of the reactor; andin the second operational mode:providing an oxidizing gas stream to a first gas inlet of the reactor;providing an inert gas stream or a reducing gas stream to a second gas inlet of the reactor, such that:the inert gas stream or the reducing gas stream flows co-currently with the oxidizing gas stream; andthe oxidizing gas stream contacts the metal oxide particles at the lower oxidation state, thereby regenerating the metal oxide particles to the oxidized stateAttorney Docket No. 029784-0014-W001and generating a second gas output comprising hydrogen gas (Hs) and / or carbon monoxide (CO); andcollecting a second gas output stream comprising hydrogen gas (H2) and / or carbon monoxide (CO) from a second gas outlet of the reactor.Embodiment 13. The method according to embodiment 12, further comprising, in the first and second operational modes, maintaining the reactor at a temperature of 300 °C to 1200 °C and a pressure of 0.1 MPa to 3 MPa.Embodiment 14. The method according to embodiment 12 or 13, further comprising recycling the second gas output stream to the second gas inlet of the reactor such that the second gas output stream is used as the reducing gas stream.Embodiment 15. The method according to any one of embodiments 12-14, wherein:a fluid carbonaceous feed residence time in the reactor is 1-10 seconds; andan oxidizing gas residence time in the reactor is 1-10 seconds.Embodiment 16. The method according to any one of embodiments 12-15, wherein the oxidizing gas stream comprises air, oxygen (O2), steam (H2O), and / or carbon dioxide (CO2).Embodiment 17. The method according to any one of embodiments 12-16, wherein:the inert gas stream comprises nitrogen (N2), helium (He), and / or argon (Ar); and the reducing gas stream comprises hydrogen gas (H2), carbon monoxide (CO), and / or methane (CH4).Embodiment 18. The method according to any one of embodiments 12-17, wherein the first gas output stream comprises at least 80 vol% carbon monoxide (CO) and hydrogen gas (H2).Embodiment 19. The method according to any one of embodiments 12-18, wherein the fluid carbonaceous feed is generated by:Attorney Docket No. 029784-0014-W001receiving solid fuel in a gasifier;generating a carbonaceous gas and solid byproducts in the gasifier; andseparating the carbonaceous gas from the solid byproducts.Embodiment 20. The method according to any one of embodiments 12-19, wherein the fluid carbonaceous feed comprises:a carbonaceous liquid comprising crude oil, gasoline, diesel, glycerol, or a combination thereof; and / ora carbonaceous gas comprising biogas, natural gas, shale gas, a gas generated by gasification of a solid fuel, an industrial waste gas, or a combination thereof.

Claims

Attorney Docket No. 029784-0014-W001CLAIMS1. A reactor system, comprising:a reactor having an inner volume and comprising:an upper fixed bed comprising metal oxide particles in an oxidized state, the upper fixed bed occupying 10-90 volume percent (vol%) of the inner volume;a lower fixed bed comprising metal oxide particles in a reduced state, the lower fixed bed occupying 10-90 vol% of the inner volume,wherein the upper fixed bed and the lower fixed bed together occupy from 50 vol% to 99 vol% of the inner volume, and a volume ratio of the upper fixed bed to the lower fixed bed is between 1 :9 and 9:1; anda separation layer positioned between the upper fixed bed and the lower fixed bed and comprising an inert material, the separation layer occupying 1-50 vol% of the inner volume;a feed inlet in fluid communication with a carbonaceous feedstock source comprising carbonaceous feed, the feed inlet configured to receive carbonaceous feed from the carbonaceous feedstock source and provide the carbonaceous feed to the upper fixed bed;a first gas outlet in fluid communication with the lower fixed bed, the first gas outlet configured to selectively discharge a first gas output stream comprising hydrogen gas (H2) and carbon monoxide (CO);a first gas inlet in fluid communication with a first gas source comprising an oxidizing gas, the first gas inlet configured to selectively provide an oxidizing gas stream to the separation layer;a second gas inlet in fluid communication with a second gas source comprising an inert gas or a reducing gas, the second gas inlet configured to selectively provide an inert gas stream or a reducing gas stream to the lower fixed bed; anda second gas outlet disposed near a top of the upper fixed bed, the second gas outlet configured to selectively discharge a second gas output stream.

2. The reactor system according to claim 1, wherein the second gas outlet is in fluid communication with the second gas inlet, the second gas outlet configured to circulate the secondAttorney Docket No. 029784-0014-W001gas output stream to the first gas inlet such that the second gas output stream is used as the reducing gas stream.

3. The reactor system according to claim 1, the reactor comprising a plurality of feed inlets arranged vertically along a side of the reactor.

4. The reactor system according to claim 1, wherein the carbonaceous feedstock source is a gasifier configured to:receive solid fuel;generate a carbonaceous gas and solid byproducts;separate the solid byproducts from the carbonaceous gas; andprovide the carbonaceous gas to the feed inlet of the reactor.

5. The reactor system according to claim 4, wherein the gasifier comprises:a solid fuel inlet configured to receive solid fuel, the solid fuel inlet being in fluid communication with a solid carbonaceous feedstock source;a carbonaceous gas outlet in fluid communication with the feed inlet of the reactor, the carbonaceous gas outlet configured to provide a carbonaceous gas stream to the feed inlet; anda solid byproducts outlet configured to discharge solid byproducts, the solid byproducts comprising ash and / or char.

6. The reactor system according to claim 4, wherein the solid fuel comprises coal, biomass, petroleum coke, solid waste, and / or plastics.

7. The reactor system according to claim 1, wherein the metal oxide particles in the oxidized state and the metal oxide particles in the reduced state each independently comprise a metal oxide of iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), calcium (Ca), magnesium (Mg), sodium (Na), potassium (K), lithium (Li), strontium (Sr), barium (Ba), titanium (Ti), or a combination thereof.Attorney Docket No. 029784-0014-W0018. The reactor system according to claim 1 , wherein the metal oxide particles in the oxidized state comprise calcium ferrite (Ca2Fc20s), iron (III) oxide (Fe2O3), manganese (III) oxide (MmCh), cobalt (II, III) oxide (CO3O4), or a combination thereof.

9. The reactor system according to claim 1, wherein the metal oxide particles in the reduced state comprise iron (II) oxide (FeO), manganese (II) oxide (MnO), cobalt (II) oxide (CoO), or a combination thereof.

10. The reactor system according to claim 1, wherein the separation layer is a bed of inert particles, a perforated ledge, or a perforated disc.

11. The reactor system according to claim 10, wherein the inert particles comprise silica (SiCh), magnesia (MgO), quartz, sand, alumina (AI2O3), or a combination thereof.

12. A method of operating a reactor system in a first operational mode and a second operational mode, the reactor system comprising a reactor comprising an upper fixed bed comprising metal oxide particles in an oxidized state, a lower fixed bed comprising metal oxide particles in a reduced state, and a separation layer positioned between the upper fixed bed and the lower fixed bed, the method comprising:in the first operational mode:providing fluid carbonaceous feed to a feed inlet of the reactor such that:the fluid carbonaceous feed contacts the metal oxide particles in the upper fixed bed, thereby reducing the metal oxide particles to a lower oxidation state and generating a gaseous product mixture;the gaseous product mixture flows to the lower fixed bed and contacts the metal oxide particles in the reduced state with the gaseous product mixture, thereby generating a first gas output comprising hydrogen gas (H2) and carbon monoxide (CO); andcollecting a first gas output stream comprising hydrogen gas (H2) and carbon monoxide (CO) from a first gas outlet of the reactor; andin the second operational mode:Attorney Docket No. 029784-0014-W001providing an oxidizing gas stream to a first gas inlet of the reactor; providing an inert gas stream or a reducing gas stream to a second gas inlet of the reactor, such that:the inert gas stream or the reducing gas stream flows co-currently with the oxidizing gas stream; andthe oxidizing gas stream contacts the metal oxide particles at the lower oxidation state, thereby regenerating the metal oxide particles to the oxidized state and generating a second gas output comprising hydrogen gas (H2) and / or carbon monoxide (CO); andcollecting a second gas output stream comprising hydrogen gas (H2) and / or carbon monoxide (CO) from a second gas outlet of the reactor.

13. The method according to claim 12, further comprising, in the first and second operational modes, maintaining the reactor at a temperature of 300 °C to 1200 °C and a pressure of 0.1 MPa to 3 MPa.

14. The method according to claim 12, further comprising recycling the second gas output stream to the second gas inlet of the reactor such that the second gas output stream is used as the reducing gas stream.

15. The method according to claim 12, wherein:a fluid carbonaceous feed residence time in the reactor is 1-10 seconds; andan oxidizing gas residence time in the reactor is 1-10 seconds.

16. The method according to claim 12, wherein the oxidizing gas stream comprises air, oxygen (O2), steam (H2O), and / or carbon dioxide (CO2).

17. The method according to claim 12, wherein:the inert gas stream comprises nitrogen (N2), helium (He), and / or argon (Ar); and the reducing gas stream comprises hydrogen gas (H2), carbon monoxide (CO), and / or methane (CH4).Attorney Docket No. 029784-0014-W00118. The method according to claim 12, wherein the first gas output stream comprises at least 80 vol% carbon monoxide (CO) and hydrogen gas (H2).

19. The method according to claim 12, wherein the fluid carbonaceous feed is generated by:receiving solid fuel in a gasifier;generating a carbonaceous gas and solid byproducts in the gasifier; andseparating the carbonaceous gas from the solid byproducts.

20. The method according to claim 12, wherein the fluid carbonaceous feed comprises:a carbonaceous liquid comprising crude oil, gasoline, diesel, glycerol, or a combination thereof; and / ora carbonaceous gas comprising biogas, natural gas, shale gas, a gas generated by gasification of a solid fuel, an industrial waste gas, or a combination thereof.

Images