Heat-integrated chemical looping of carbon and hydrogen

Abstract

The heat-integrated reaction process includes conducting one or more exothermic reactions to generate heat and form solid carbon from reactant gases including CO, hydrocarbons, and CO, transferring at least a portion of the heat from the one or more exothermic reactions to at least one endothermic reaction of one or more endothermic reactions, and conducting the one or more endothermic reactions using the heat transferred from the one or more exothermic reactions.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 481,720, entitled "HEAT INTEGRATED CHEMICAL LOOPING FORMATION OF CARBON AND HYDROGEN," filed January 26, 2023, the entire disclosure of which is incorporated herein by reference. [Background technology]

[0002] Industrial hydrogen can be primarily produced by reacting hydrocarbon feedstocks (e.g., CH4, naphtha, biomass, coal, etc.) with oxygen-containing species (e.g., O2, HO, CO2) to create the desired mixture of H2, CO2, and HO. Overall, the carbon input into the system exists as CO2, which is typically released into the environment or, in future scenarios, geologically sequestered. This results in significant additional costs arising from CO2 handling and sequestration process costs, carbon taxes, or negative externalities to society (e.g., climate change). Summary of the Invention

[0003] In some embodiments, the heat-integrated reaction process includes conducting one or more exothermic reactions to generate heat and form solid carbon from reactant gases including CO, hydrocarbons, and CO, transferring at least a portion of the heat from the one or more exothermic reactions to at least one endothermic reaction of one or more endothermic reactions, and conducting the one or more endothermic reactions using the heat transferred from the one or more exothermic reactions.

[0004] In some embodiments, a system for converting hydrocarbons to solid carbon and hydrogen includes a first reactor configured to at least partially convert the hydrocarbons with HO and / or CO into a first product stream comprising CO, CO, HO, and H, a second reactor configured to receive the first product stream and further convert the first product stream to produce a second product stream, and a third reactor configured to receive the second product stream and conduct an exothermic reaction to convert at least a portion of the CO and CO in the second product stream to solid carbon. At least a portion of the heat released in the exothermic reaction is transferred to the first reactor.

[0005] These and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims.

[0006] For a more complete understanding of the present disclosure, the following brief description, taken in conjunction with the accompanying figures and detailed description, is now set forth. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 shows a schematic diagram of the integration of exothermic and endothermic reactions according to some embodiments. [Figure 2] FIG. 2 illustrates a schematic of a carbon formation system according to some embodiments. [Figure 3] FIG. 3 illustrates a schematic diagram of another carbon formation system according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0008] Disclosed herein are systems and methods for integrating exothermic and endothermic reactions to produce solid carbon and / or metal carbides from carbon monoxide and / or carbon dioxide. The systems and methods described herein are based on converting hydrocarbon materials, such as natural gas or other molecules, or mixtures of molecules containing primarily hydrogen and carbon atoms, into a solid carbon product that can be easily handled and prevented from forming carbon oxides in the atmosphere, as well as gas phase by-products (e.g., hydrogen, unreacted hydrocarbons, other pyrolysis products, etc.) and water. In some embodiments, the gas phase by-product, hydrogen, can be used as a fuel or chemical.

[0009] A major challenge with the two-step process for producing solid carbon, hydrogen, and water from hydrocarbon feedstocks via intermediate carbon dioxide gases is that while hydrocarbon conversion reactions tend to be endothermic, all of the carbon-forming reactions from carbon dioxide gases are strongly exothermic. For example, the steam methane reforming and CO reduction reactions have standard heats of reaction of 206 kJ / mol CH4 and -131 kJ / mol CO, respectively. The overall energy efficiency of the process is low if the heat from the exothermic reaction is not used to drive the endothermic reaction first or for other beneficial uses (e.g., to generate steam to drive a turbine and generate electricity). Various considerations, including temperature and pressure for both reactions, catalyst use, and reactor design, must be taken into account to achieve sufficient reaction rates and thermodynamic equilibrium conversion so that the heat from the exothermic reaction can drive the endothermic conversion in a practical reactor design.

[0010] Disclosed herein are process designs for coupling an exothermic carbon production reaction from carbon oxide gas to one of several endothermic reactions. The exothermic carbon production reaction from carbon oxide gas may include:

number

[0011] The endothermic reaction may produce H and / or CO, which may be used to convert carbon oxides to carbon via one of the exothermic reactions. Endothermic reactions may include:

number

[0012] The thermal coupling of the exothermic reactant gas stream 1 and the endothermic reactant gas stream 2 is This can occur in one of several ways. First, stream 2 can pass through a conduit or tube in an exothermic reactor (e.g., a fluidized bed reactor), which allows heat from stream 1 and / or the medium in the reactor to be easily transferred to stream 2. An endothermic reaction can occur while and / or after heat is being transferred to the gas. In some cases, it can be advantageous to perform the endothermic reaction at a separate location, as the endothermic reaction can be kinetically slow and may require excessive volume in the exothermic reactor to achieve acceptable conversion.

[0013] Alternatively, after Stream 1 leaves the exothermic reactor, it can transfer heat to Stream 2 in any dedicated heat exchanger and / or in the vessel where the endothermic reaction is occurring. This can be advantageous when it is difficult to integrate tubing into the exothermic reactor.

[0014] 1 shows a schematic diagram of the thermal integration of one or more exothermic and one or more endothermic reactions that can form solid carbon from carbon-containing gases such as carbon monoxide, carbon dioxide, and / or hydrocarbons (e.g., methane). The exothermic reactions can use exothermic reactant and product stream 1, while the endothermic reactions can use endothermic reactant and product stream 2. Heat released by the exothermic reactions can be transferred to endothermic stream 2 within the exothermic reactor itself and / or within the endothermic reactor using heat exchangers external to the endothermic and exothermic reactors.

[0015] As described herein, the exothermic reaction can form solid carbon from carbon-containing gases such as hydrocarbons, carbon dioxide, and / or carbon monoxide. In some embodiments, the hydrocarbon gas can include methane and / or natural gas, although any suitable hydrocarbon can be used. For example, the hydrocarbon can include lower alkanes such as methane, ethane, natural gas, and other gaseous, liquid, solid hydrocarbons (e.g., alcohols, crude oil, vegetable oil, biomass, naphtha, etc.), and any mixture thereof. In some embodiments, a gasification reactor can be used to convert one or more hydrocarbon-containing species into a gaseous stream of hydrocarbons for further processing.

[0016] The exothermic reaction can occur under any suitable conditions and in any suitable reactor configuration. In some embodiments, the exothermic reaction can occur in a fluidized bed reactor, a moving bed reactor, an entrained bed reactor, a fixed bed reactor, etc. Generally, the exothermic reaction can occur at temperatures from about 400°C to about 1000°C, or from about 500°C to about 750°C, and at pressures from about 1 to 50 bar.

[0017] In some embodiments, heterogeneous catalysts may be used in exothermic reactors. Exothermic reactors may use catalysts that promote the reaction and formation of solid carbon. The catalytic material may include any material suitable for catalyzing the formation of a solid carbon material from carbon oxides and gaseous reduced materials. By way of example, the catalytic material may be an element from Group VI, Group VII, or Group VIII of the Periodic Table of the Elements (e.g., iron, manganese, silicon, magnesium, calcium, sodium, aluminum, titanium, nickel, molybdenum, platinum, palladium, rhodium, ruthenium, chromium, cobalt, tungsten, etc.), an actinide, a lanthanide, an oxide thereof, an alloy thereof, or a combination thereof. Any metal known to be subject to metal coking may also be suitable for use as a catalytic material.

[0018] The catalyst may be applied within the exothermic reactor (e.g., within the reaction chamber) as one or more solid structures (e.g., particles, wafers, cylinders, plates, sheets, spheres, pellets, mesh, fibers, etc.) and / or as at least a partial coating on another structure within the reactor vessel (e.g., particles of at least one material deposited on a structure such as a wafer, cylinder, plate, sheet, sphere, mesh, pellet, etc.). In some embodiments, the catalyst may be applied to the reaction chamber. The catalyst material may be applied to the exothermic reactor as a plurality of particles or particulates. The catalyst material may be fixed (e.g., as a catalyst bed) or mobile (e.g., as a fluidized bed) within the reactor. In some embodiments, a portion of the catalyst material may be mobile within the reactor and another portion of the catalyst material may be fixed within the reactor.

[0019] The exothermic reaction may include any reaction capable of forming solid carbon from a carbon-containing gas, such as a hydrocarbon, carbon monoxide, and / or carbon dioxide. Suitable exothermic reactions may include, but are not limited to, a CO reduction reaction, a Boudouard reaction, a CO reduction reaction, and / or a hydrocarbon oxidation reaction involving carbon formation (e.g., methane reacts with oxygen to produce solid carbon and carbon monoxide, carbon dioxide, and / or water).

[0020] As described herein, the endothermic reaction can occur using at least a portion of the heat provided by the exothermic reaction. In some embodiments, the endothermic reaction can produce one or more products used in the exothermic reaction to produce solid carbon. For example, an endothermic reaction can produce carbon monoxide, hydrogen, and water from reactants including a hydrocarbon, water, carbon dioxide, hydrogen, and solid carbon. When a hydrocarbon reactant is used in the endothermic reaction, the hydrocarbon can include any of those described herein and can be the same or different from the hydrocarbon used in the exothermic reaction.

[0021] The endothermic reaction(s) can occur under any suitable conditions and in any suitable reactor configuration. In some embodiments, the endothermic reaction can occur in a fluidized bed reactor, a moving bed reactor, an entrained bed reactor, a fixed bed reactor, etc. Generally, the endothermic reaction can occur at a temperature of about 400°C to about 1000°C, or about 500°C to about 750°C, and at a pressure of about 1 to 50 bar. In some embodiments, the endothermic reaction(s) can occur at a pressure higher, lower, or substantially the same as the pressure of the exothermic reaction(s).

[0022] Endothermic reactions may include, but are not limited to, steam methane reforming reactions, dry reforming reactions, hydrocarbon pyrolysis reactions, reverse water gas shift reactions, steam gasification of carbon, and / or reverse Boudouard reactions.

[0023] In some embodiments, the endothermic reaction(s) may include a steam methane reforming (SMR) reaction carried out in an SMR unit. The SMR unit may carry out a reaction of water with a hydrocarbon feed to form CO and H. An exemplary SMR reaction, using methane as an example, may proceed as follows: CH4+H2O⇔CO+3H2

[0024] The SMR unit can carry out the reforming reaction in a reactor vessel, which may contain a catalyst to improve the reforming reaction rate. The hydrocarbon feed can include any of the hydrocarbon feeds described herein, such as methane. The feed to the SMR unit can also include steam. In some embodiments, the reformer can include any suitable reactor, such as, for example, a tubular reactor, a multi-tubular reactor, or the like, or a combination thereof.

[0025] In certain embodiments, the SMR unit may include a nickel-based catalyst (e.g., a sulfur-sensitive nickel-based catalyst) and / or a sulfur-passivated nickel-based catalyst (to avoid carbon deposition). The reforming reaction for hydrocarbons such as methane may be endothermic, with the reaction rate dependent on temperature, pressure, and catalyst type. The endothermic nature of the reforming reaction may be balanced with an exothermic reaction based on the reaction of oxygen with the hydrocarbon, such that the overall reaction is autothermal or substantially autothermal. Hydrocarbons may undergo reforming reactions at high temperatures, but in the presence of a catalyst (e.g., a nickel-based catalyst), the temperature at which the hydrocarbons can be reformed may be reduced. The SMR reaction may be carried out at temperatures between about 700°C and about 1100°C, or between about 800°C and about 900°C. In embodiments, the reformer may be characterized by a reforming pressure of from about 1 bar to about 50 bar.

[0026] In some embodiments, the endothermic reaction can include the dry reforming of methane (DRM) reaction. Dry reforming of hydrocarbons occurs according to the following reaction: CH4 + CO2 ⇔ 2CO + 2H2

[0027] The DRM unit can carry out the reforming reaction in a reactor vessel, which may contain a catalyst to improve the reforming reaction rate. The reactor can take a wide variety of forms, including fixed-bed reactors, fluidized-bed reactors, and moving-bed reactors. The hydrocarbon feed can contain hydrocarbons, such as methane and carbon dioxide, in equimolar or near-equimolar amounts. Although described as containing methane, other hydrocarbon-containing streams can also be used, including any of those described herein. The DRM unit may operate water-free or substantially water-free.

[0028] The DRM unit may optionally operate in the presence of any suitable catalyst(s). Exemplary catalysts may include supported or bulk catalysts containing Group VIII (rows 8-10) metals that are catalytically active for reforming reactions. By way of example, catalysts based on nickel, rhodium, ruthenium, or platinum, or any combination thereof, may be used in dry methane reforming.

[0029] The reaction conditions in the DRM are a pressure of about 1 bar to about 50 bar, or about 1 bar to about 20 bar, a temperature of about 750°C to about 1100°C, or about 800°C to about 950°C, and a reaction rate of about 500 / h. ―1 ~About 100,000 / h ―1 In some embodiments, the conversion of hydrocarbons (e.g., methane, etc.) in the reaction may be from about 60% to about 80%. The hydrogen gas to carbon monoxide ratio (H2 / CO) in the product stream leaving the DRM unit may range from about 0.5 to about 1. Additionally, some amount of unreacted hydrocarbon gas and carbon dioxide may also be present, depending on the overall conversion.

[0030] In some embodiments, the endothermic reaction(s) may include a reverse water gas shift (rWHS) reaction. The rWHS reactor may convert CO to CO using H according to the following equation: CO2+H2⇔CO+H2O

[0031] The rWGS reaction can be operated in the presence of one or more catalysts. Suitable catalysts are ZnO, MnO x , alkaline earth metal oxides, complex (or mixed metal) oxides. Additional rWGS catalysts are known in the art.

[0032] The rWGS reaction can be carried out in one or more suitable reactors, such as adiabatic or heated reactors. Reactor vessels such as fixed-bed reactors, fluidized-bed reactors, and the like can be used. For example, the rWGS reactor can include a fixed-bed catalyst disposed in one or more tubular reactors configured in an adiabatic reactor or in a thermal reactor with an externally heated tubular reactor. The rWGS reactor can be operated at temperatures ranging from about 500°C to about 800°C and at any suitable pressure used in the system, e.g., from about 1 bar to about 50 bar, or between about 5 bar and about 20 bar. The efficiency of CO2 conversion to CO can exceed 30%.

[0033] In some embodiments, the endothermic reaction(s) may include a steam gasification reaction. Gasification involves the thermal treatment of a carbon feedstock with an oxidant stream to produce synthesis gas. Steam gasification may use water as an oxidant that reacts with carbon to produce carbon monoxide and hydrogen as a synthesis gas mixture. Steam gasification may be represented by the following equation: HO + C → CO + H Gasification can be carried out in any suitable reactor vessel. The reactor may be configured to accommodate gas velocities and configurations. The gasifier may be a fixed bed, fluidized bed, or entrained flow gasifier, or some variation thereof, based on the steam gasification process. The type and extent of reaction in the gasifier depends on the design and operating conditions of the gasifier. The temperature of the steam gasification process may be from about 800°C to about 1500°C.

[0034] In some embodiments, the endothermic reaction(s) may include a reverse Boudouard reaction. The reverse Boudouard reaction (RBR) may be used to produce CO from CO and solid carbon. The RBR may be represented by the following equation: CO2+C→2CO

[0035] RBR can be used in any suitable reactor and can employ a catalyst. In some embodiments, the RBR reaction can occur in a fluidized bed reactor, a moving bed reactor, a fixed bed reactor, or the like. Generally, the RBR reaction can occur at temperatures from about 600°C to about 1200°C.

[0036] In an RBR, CO2 can be combined with carbon and converted to carbon monoxide, which is thermodynamically favorable at high temperatures. Various catalysts can be used, such as iron-based catalysts, which can be deposited on elemental carbon supports. Alkali carbonates have also been used to catalyze char gasification with CO2. Additional catalysts can include mixed metal oxides with nickel, ceria, and zirconia. The overall RBR reaction can produce a carbon monoxide stream for further use in the system.

[0037] Although described as separate reactions, one or more of the endothermic reactions may occur simultaneously in the same reactor depending on the composition of reactants and products present, as well as the reaction conditions and catalyst, if any, used.

[0038] The integration of exothermic and endothermic reactions can be used in processes and systems for converting hydrocarbons to solid carbon and hydrogen. The processes and systems can use multiple reactors for carrying out the reactions. A first reactor can be used to convert a hydrocarbon-containing feed with HO and / or CO to CO, CO, HO, and H to produce a partially reacted product stream. A second reactor can be used to convert the partially reacted product stream from the first reactor to produce an intermediate stream. The intermediate stream can include water and hydrogen, among other components. Some portion of the water and hydrogen can optionally be removed from the intermediate stream before it can be transferred to the third reactor. In the third reactor, carbon monoxide and carbon dioxide can react exothermically to form solid carbon and other reaction products. The resulting heat released in the third reactor can then be used in the reaction in the first reactor. For example, the heat can be transferred to the first reactor itself and / or one or more streams entering the first reactor. In some embodiments, the second reactor can be heated using a combustion source, such as hydrogen produced in the system, thereby avoiding the formation of carbon oxides due to burning hydrocarbons.

[0039] The hydrocarbons used in the system can include any of the hydrocarbons or hydrocarbon mixtures described herein, such as lower alkanes such as methane and ethane, natural gas, and other gaseous, liquid, and solid hydrocarbons (e.g., alcohols, crude oil, vegetable oil, biomass, naphtha, etc.), and any mixtures thereof. The multiple reactors can be operated under any suitable conditions, for example, at pressures from about 1 bar to about 50 bar, or from about 5 bar to about 20 bar. In some embodiments, the first and second reactors can be operated at different pressures than the third reactor. The first and third reactors can be operated at temperatures from about 400°C to about 1000°C.

[0040] The third reactor may be a carbon-forming reactor, which may be configured in any suitable configuration. In some embodiments, the third reactor contains a moving bed of particles (e.g., In some embodiments, the third reactor may comprise a fluidized bed comprising catalyst particles. The catalyst may comprise one or more catalyst components including any of those described herein, such as Fe, Mn, Co, Ni, Si, Mg, Ca, Na, Al, Ti, Pt, Pd, Rh, and / or Ru. The first and second reactors may comprise catalysts for converting hydrocarbons, where the catalyst may be selected based on the particular endothermic reaction being performed, including any of those described herein for the particular reaction. In some embodiments, the first and / or second reactors may comprise a catalyst comprising one or more of Fe, Mn, Co, Ni, Si, Mg, Ca, Na, Al, Ti, Pt, Pd, Rh, and / or Ru.

[0041] An embodiment of a system and associated process for converting hydrocarbons to solid carbon and hydrogen is shown in FIG. 2. As shown, multiple reactors, such as a heat-integrated reactor 202 and a second reactor 214, can be coupled to enable the conversion of hydrocarbons to solid carbon along with the production of hydrogen. As shown, a hydrocarbon stream 201 containing one or more hydrocarbons, a water stream 203 containing water, and, optionally, a recycle stream 221 containing separated hydrocarbons, can be passed to a first reaction or reactor as part of the heat-integrated reactor 202, which can be used to form a product stream 205 containing CO, H, CO, and HO while still containing some amounts of unreacted components of the feed stream, such as the hydrocarbon(s) and water portions. The hydrocarbon stream can include any of the hydrocarbons described herein. The SMR reaction occurring in the heat-integrated reactor 202 can occur using the conditions, catalysts, and reactors described herein for the SMR process.

[0042] Heat-integrated reactor 202 is shown as a single reactor containing multiple reactor passes, such as an SMR conversion pass for converting a hydrocarbon feedstream containing HO and / or CO to CO, CO, HO, and H to produce a partially reacted product stream. A second reactor pass may include a carbon-forming reaction that produces solid carbon and hydrogen. While heat-integrated reactor 202 is shown as a single unit with two thermally coupled reactions, heat-integrated reactor 202 may include a single vessel with separate reactions and / or separate vessels that are thermally coupled using various heat exchanger configurations.

[0043] Product stream 205 may be transferred to second reactor 214, which may be used to further convert components of product stream 205 to produce intermediate stream 207. Intermediate stream 207 may include water and hydrogen, among other components. Second reactor 214 may perform an additional SMR reaction on product stream 205 to produce an intermediate stream. The SMR reaction performed by second reactor 214 may occur using the conditions, catalysts, and reactors described herein for the SMR process, and the conditions and catalysts within second reactor 214 may be the same or different from those occurring in the SMR reaction in heat-integrated reactor 202.

[0044] Because the reaction in second reactor 214 is endothermic, a heat source may be applied to add heat to the stream entering the reactor and / or within the reactor. In some embodiments, a combustion reaction may be used to combust a fuel source to generate heat for use in the endothermic reaction in second reactor 214. While shown in Figure 2 as burning hydrocarbons with air, other combustion sources may be used, such as using hydrogen, burning with air or an oxygen stream. Various sources for fuel may be used, such as unreacted hydrocarbons from optional hydrocarbon separation process 212 and / or separated hydrogen in stream 223.

[0045] The resulting intermediate stream 207 may be a mixture of at least a portion of the water in the intermediate stream 207. The intermediate stream 207 may be transferred to a condenser 216 for removal of the water. The condenser 216 may cool the intermediate stream 207 to between 0°C and 50°C, or below 30°C, to condense at least a portion of the water, which may be removed as a liquid stream.

[0046] The remaining gas phase constituents from condenser 216 may pass as stream 209 to compressor 218 and be compressed upstream of separation unit 220. The resulting compressed stream 211 may pass entirely to separator 220, or optionally, all or a portion of the stream may pass as bypass stream 213 to the inlet of the carbon-forming reaction in heat-integrated reactor 202.

[0047] Separator 220 may serve to separate at least a portion of any hydrogen in stream 211. Stream 211 may contain CO, H, CO, and unreacted hydrocarbons, along with small amounts of remaining water. The hydrogen in stream 211 may be removed in separator 220 to form hydrogen stream 223. As shown in FIG. 2, a pressure swing adsorption (PSA) unit may be used to separate at least a portion of the hydrogen from stream 211 from condenser 216. While shown as a PSA unit, other suitable separation units, such as temperature swing adsorption, membrane units, etc., may also be used to separate at least a portion of the hydrogen. In some embodiments, at least about 50%, at least about 60%, at least about 70%, at least about 80%, or at least about 90% of the hydrogen (by volume) in stream 211 from condenser 216 may be separated in separation unit 220 to form hydrogen product stream 223 and hydrogen-reduced stream 215.

[0048] Stream 215 may then pass through compressor 222 before moving to heat-integrated reactor 202. The stream leaving the compressor may contain primarily CO, CO, and unreacted hydrocarbons, with some remaining small amounts of hydrogen, water, and trace components. An optional amount of an intermediate stream taken downstream of condenser 216 and compressor 218 may be added into the stream from compressor 222 along with an amount of recycle stream 219 to form feed stream 217 to the carbon-forming reactor portion of heat-integrated reactor 202. The relative amounts of bypass stream 213 and recycle stream 219 added into the stream from compressor 222 may be based on the amounts of CO, CO, hydrocarbons, and H in each stream so that the relative amounts of each component can be controlled in the carbon-forming reaction.

[0049] Within the heat-integrated reactor 202, carbon monoxide and carbon dioxide may react exothermically to form solid carbon and other reaction products. The resulting heat released in the carbon-forming reactor may then be used in reactions in the SMR reaction as part of the heat-integrated reactor 202. For example, heat may be transferred to the first reactor itself and / or one or more streams entering the first reactor. The exothermic reaction in the carbon-forming reactor may include any of the exothermic reactions described herein, including the reaction conditions and catalysts described herein. The solid carbon may be removed using various downstream solid separators, such as a cyclone, baghouse, etc. Alternatively, all or a portion of the solids may be removed by gravity from the heat-integrated reactor 202. The gas-phase products may then be discharged from the heat-integrated reactor 202 for downstream processing.

[0050] The heat-integrated reactor 202 can include heat integration between the exothermic carbon-forming reaction and the endothermic SMR reaction. In some embodiments, the two reactions can be carried out at least partially within a single vessel. For example, the endothermic reaction can be carried out in a conduit or tube with the reaction vessel carrying out the exothermic carbon-forming reaction, or the exothermic reaction can occur in a conduit and tube while the SMR reaction occurs in the reaction vessel. In some embodiments, heat from the carbon-forming reaction is transferred to the endothermic reaction using a separate heat exchanger to separate the heat from the products of the exothermic reaction. Heat may be transferred to the reactants of the endothermic reaction before they enter the separate reactor vessel. In yet other configurations, heat from the carbon-forming reaction may be transferred to the endothermic reaction using heat exchange surfaces within the endothermic reactor, and heat from the products of the exothermic reaction may be transferred to the endothermic reactor vessel. In any of these configurations, heat from the exothermic reaction that produces solid carbon may be transferred to the endothermic reaction.

[0051] The gas phase products from the carbon-forming reaction may be discharged from the heat-integrated reactor 202 to a condenser 204, which may cool the product stream and condense at least a portion of the water. When any solids are present in the gas phase stream (e.g., solid carbon, catalyst particles, heat carrier particles, etc.), one or more solid separators may be used between the carbon-forming reaction and the condenser 204. The remaining gas phase products from the condenser may be transferred to an optional separation train and / or returned to the compressor to recompress the gas phase components before being returned to the inlet of the carbon-forming reactor in recycle stream 219.

[0052] When optional separation trains are used, all or a portion of the gas-phase product may be transferred to a CO separation unit 208. The separated CO may be recycled to compressor 206. The remaining gas-phase components may be transferred to a CO separation unit 210, which may return the captured CO to compressor 206. CO separation unit 208 and CO separation unit 210 may include any suitable units configured to separate CO and / or CO, where CO separation unit 208 and CO separation unit 210 may be combined into a single unit in some embodiments. Various units, such as a solvent-based contactor, may be used to separate CO and / or CO from the gas-phase product stream.

[0053] The remaining gas phase product may contain unreacted hydrocarbons along with some trace amounts of water, CO, CO, and H. A hydrocarbon separation unit 212 can be used to purify the hydrocarbons, which can then be used as fuel to the second reactor 214 and / or returned to the inlet of the process as feed to the first SMR reactor as part of the heat integrated reactor 202.

[0054] Overall, the system 200 and corresponding process shown in FIG. 2 can be used to convert hydrocarbons to solid carbon and hydrogen, integrating heat from one or more exothermic reactions that produce solid carbon with endothermic reactions used to produce intermediates in the conversion process.

[0055] A similar system 300 and corresponding process is shown in FIG. 3. Identical or similar units or components will not be described in detail again for the sake of brevity. Components with the same reference numbers may be the same or similar to those described with respect to FIG. 2. System 300 may be used to heat-integrate a system using a DRM reaction with a carbon-forming reaction that produces solid carbon and hydrogen. As shown, multiple reactors, such as heat-integrated reactor 302 and DRM reactor 314, may be coupled to enable the conversion of hydrocarbons to solid carbon with the production of hydrogen. As shown, a hydrocarbon stream 201 containing one or more hydrocarbons, an optional water stream 203 containing water, and optionally a recycle stream containing CO may be passed to a first reaction or reactor as part of heat-integrated reactor 302, which may contain some amounts of unreacted components of the feed stream, such as the hydrocarbon(s) and water portions, but may be used to form a product stream 305 containing CO, H, CO, and HO. The system is similar to system 200, except that a DRM reaction may be used instead of an SMR reaction. The hydrocarbon stream may contain any of the hydrocarbons described herein. The DRM reaction occurring in heat-integrated reactor 302 may be performed under the conditions, catalysts, and / or methods described herein for the DRM process. and reactors.

[0056] The heat-integrated reactor 302 is shown as a single reactor containing multiple reactor passes, such as a DRM conversion pass for converting a hydrocarbon feedstream containing CO to CO, CO, HO, and H to produce a partially reacted product stream. A second reactor pass may include a carbon-forming reaction that produces solid carbon and hydrogen. Although the heat-integrated reactor 302 is shown as a single unit with two thermally coupled reactions, the heat-integrated reactor 302 may include a single vessel with separate reactions and / or separate vessels that are thermally coupled using various heat exchanger configurations.

[0057] Product stream 305 may be transferred to second reactor 314, which may be used to further convert components of product stream 305 to produce intermediate stream 307. Intermediate stream 307 may include water and hydrogen (e.g., CO, CO, H, etc.), among other components. Second reactor 314 may perform a further DRM reactor on product stream 305 to produce intermediate stream 307. The DRM reaction performed by reactor 314 may occur using the conditions, catalysts, and reactors described herein for the DRM process, and the conditions and catalysts in reactor 314 may be the same or different from those occurring in the DRM reaction in heat-integrated reactor 302.

[0058] Because the reaction in reactor 314 is endothermic, a heat source can be applied to add heat to the stream entering the reactor and / or within the reactor. In some embodiments, a combustion reaction can be used to combust a fuel source to generate heat used in the endothermic reaction in reactor 314. While shown in Figure 3 as burning hydrocarbons with air, other combustion sources can also be used, such as burning with air or an oxygen stream, or using hydrogen. Various sources for fuel can be used, such as unreacted hydrocarbons remaining after CO and CO removal from the carbon-forming reaction and / or separated hydrogen in stream 323.

[0059] The resulting intermediate stream 307 may be passed to a condenser 216 to remove at least a portion of the water in the intermediate stream 307. The condenser 216 may cool the intermediate stream 307 to between 0°C and 5°C, or below 3°C, to condense at least a portion of the water, which may be removed as a liquid stream.

[0060] The remaining gas phase constituents from condenser 216 may pass as stream 309 to compressor 218 and be compressed upstream of separation unit 220. The resulting compressed stream 311 may pass entirely to separator 220, or optionally, all or a portion of the stream may pass as bypass stream 313 to the inlet of the carbon-forming reaction in heat-integrated reactor 302.

[0061] Separator 220 may serve to separate at least a portion of any hydrogen in stream 311. Stream 311 may contain CO, H, CO, and unreacted hydrocarbons, along with small amounts of remaining water. The hydrogen in stream 311 may be removed in separator 220 to form hydrogen stream 323. As shown in Figure 3, a PSA unit may be used to separate at least a portion of the hydrogen from stream 311 from condenser 216. While shown as a PSA unit, other suitable separation units, such as temperature swing adsorption, membrane units, etc., may also be used to separate at least a portion of the hydrogen.

[0062] Stream 315 may then pass through compressor 222 before moving to heat integrated reactor 302. The stream leaving compressor 222 is primarily CO, CO, and unreacted hydrocarbons, with some residual small amounts of hydrogen, water, and trace components. An optional amount of an intermediate stream taken downstream of condenser 216 and compressor 218 may be added into the stream from compressor 222 along with an amount of recycle stream 319 to form feed stream 317 to the carbon-forming reactor portion of heat-integrated reactor 302. The relative amounts of bypass stream 313 and recycle stream 319 added into the stream from compressor 222 may be based on the amount of CO, CO, hydrocarbons, and H in each stream so that the relative amounts of each component can be controlled in the carbon-forming reaction.

[0063] Within the heat-integrated reactor 302, carbon monoxide and carbon dioxide may react exothermically to form solid carbon and other reaction products. The resulting heat released in the carbon-forming reactor may then be used in reactions in the DRM reaction as part of the heat-integrated reactor 302. For example, heat may be transferred to the first reactor itself and / or one or more streams entering the first reactor. The exothermic reaction in the carbon-forming reactor may include any of the exothermic reactions described herein, including the reaction conditions and catalysts described herein. Solid carbon may be removed using various downstream solid separators, such as a cyclone, baghouse, etc. Alternatively, all or a portion of the solids may be removed by gravity from the heat-integrated reactor 302. The gas-phase products may then be discharged from the heat-integrated reactor 302 for downstream processing.

[0064] The heat-integrated reactor 302 can include heat integration between the exothermic carbon-forming reaction and the endothermic DRM reaction. In some embodiments, the two reactions can be carried out at least partially within a single vessel. For example, the endothermic reaction can be carried out in a conduit or tube with the reaction vessel carrying out the exothermic carbon-forming reaction, or the exothermic reaction can occur in a conduit and tube with the DRM reaction occurring in the reaction vessel. In some embodiments, heat from the carbon-forming reaction can be transferred to the endothermic reaction using a separate heat exchanger to transfer heat from the products of the exothermic reaction to the reactants of the endothermic reaction before the reactants enter the separate reactor vessel. In yet other configurations, heat from the carbon-forming reaction can be transferred to the endothermic reaction using a heat exchange surface within the endothermic reactor to transfer heat from the products of the exothermic reaction to the endothermic reactor vessel. In any of these configurations, heat from the exothermic reaction that produces solid carbon can be transferred to the endothermic reaction.

[0065] The gas phase products from the carbon-forming reaction may be discharged from the heat-integrated reactor 302 to a condenser 204, which may cool the product stream and condense at least a portion of the water. When any solids are present in the gas phase stream (e.g., solid carbon, catalyst particles, heat carrier particles, etc.), one or more solid separators may be used between the carbon-forming reaction and the condenser 204. The remaining gas phase products from the condenser may be transferred to an optional separation train and / or returned to the compressor to recompress the gas phase components before being returned to the inlet of the carbon-forming reactor in recycle stream 319.

[0066] When the optional separation train is used, all or a portion of the gas phase product may be transferred to CO separation unit 208. The separated CO may be recycled to compressor 206. The remaining gas phase components may be transferred to CO separation unit 210, which may return the captured CO to compressor 301 and then return the compressed CO to the feed to the DRM reaction in heat-integrated reactor 302. CO separation unit 208 and CO separation unit 210 may include any suitable units configured to separate CO and / or CO, where CO separation unit 208. Various units, such as solvent-based contactors, may be used to separate CO and / or CO from the gas phase product stream.

[0067] The remaining gas phase products may include unreacted hydrocarbons along with some trace amounts of water, CO, CO, and H. The stream may be combined with an oxygen source, such as air or an augmented oxygen stream, to enable combustion to provide heat for the endothermic reaction in the second reactor 314. The resulting mixture may be passed to the second reactor 314 as fuel stream 303.

[0068] Overall, the system 300 and corresponding process shown in FIG. 3 can be used to convert hydrocarbons to solid carbon and hydrogen, integrating heat from one or more exothermic reactions that produce solid carbon with endothermic reactions used to produce intermediates in the conversion process.

[0069] While various systems and methods have been described, certain aspects include, but are not limited to:

[0070] In a first embodiment, the heat-integrated reaction process includes: conducting one or more exothermic reactions to generate heat and form solid carbon from reactant gases including CO, hydrocarbons, and CO; transferring at least a portion of the heat from the one or more exothermic reactions to at least one endothermic reaction of one or more endothermic reactions; and conducting the one or more endothermic reactions using the heat transferred from the one or more exothermic reactions.

[0071] A second aspect may include the process according to the first aspect, wherein the one or more exothermic reactions comprises a CO reduction reaction.

[0072] A third aspect may include the process according to the first or second aspect, wherein the one or more exothermic reactions comprises a Boudouard reaction.

[0073] A fourth aspect may include the process of any one of the first to third aspects, wherein the one or more exothermic reactions comprises a CO2 reduction reaction.

[0074] A fifth aspect may include the process of any one of the first to fourth aspects, wherein the one or more exothermic reactions include hydrocarbons reacting with O to form solid carbon together with gaseous species including CO, CO, and HO.

[0075] A sixth aspect may include the process of any one of the first to fifth aspects, wherein the one or more exothermic reactions occur in a fluidized bed containing solid carbon, metal, metal oxide, and / or metal carbide.

[0076] A seventh aspect may include the process of the sixth aspect, wherein the metal of the metal, metal oxide, and / or metal carbide comprises at least one of Fe, Mn, Co, Ni, Si, Mg, Ca, Na, Al, Ti, Pt, Pd, Rh, Ru, or any combination thereof.

[0077] An eighth aspect may include the process of any one of the first to seventh aspects, wherein the one or more endothermic reactions include a steam methane reforming reaction.

[0078] A ninth aspect may include the process of any one of the first to eighth aspects, wherein the one or more endothermic reactions comprises a dry reforming of methane reaction.

[0079] A tenth aspect may include the process of any one of the first to ninth aspects, wherein the one or more endothermic reactions include a hydrocarbon pyrolysis reaction.

[0080] An eleventh aspect may include the process of any one of the first to tenth aspects, wherein the one or more endothermic reactions include a reverse water gas shift reaction.

[0081] A twelfth aspect may include the process of any one of the first to eleventh aspects, wherein the one or more endothermic reactions include a steam gasification of carbon reaction.

[0082] A thirteenth aspect may include the process of any one of the first to twelfth aspects, wherein the one or more endothermic reactions include a reverse Boudouard reaction.

[0083] A fourteenth aspect may include the process of any one of the first to thirteenth aspects, wherein the one or more exothermic reactions occur at a temperature of from 400 to 1000°C.

[0084] A fifteenth aspect may include the process of any one of the first to fourteenth aspects, wherein the one or more exothermic reactions occur at a pressure of about 1 to 50 bar.

[0085] A sixteenth aspect may include the process of any one of the first to fifteenth aspects, wherein the one or more endothermic reactions occur at a pressure of about 1 to 50 bar.

[0086] A seventeenth aspect may include the process of any one of the first to sixteenth aspects, wherein the one or more endothermic reactions occur at a pressure above the pressure at which the one or more exothermic reactions occur.

[0087] An eighteenth aspect may include the process of any one of the first to seventeenth aspects, wherein the one or more endothermic reactions occur at a pressure that is less than the pressure at which the one or more exothermic reactions occur.

[0088] A nineteenth aspect may include the process of any one of the first to eighteenth aspects, wherein the one or more endothermic reactions occur at about the same pressure as the one or more exothermic reactions.

[0089] A twentieth aspect may include the process of any one of the first to nineteenth aspects, wherein transferring heat to at least one endothermic reaction occurs in an exothermic reactor carrying out one or more exothermic reactions.

[0090] A twenty-first aspect may include the process of any one of the first to twentieth aspects, wherein transferring heat to at least one endothermic reaction occurs outside an exothermic reactor carrying out the one or more exothermic reactions.

[0091] In a twenty-second embodiment, a system for converting hydrocarbons to solid carbon and hydrogen includes: a first reactor configured to at least partially convert the hydrocarbons with HO and / or CO into a first product stream comprising CO, CO, HO, and H; a second reactor configured to receive the first product stream and further convert the first product stream to produce a second product stream; and a third reactor configured to receive the second product stream and conduct an exothermic reaction to convert at least a portion of the CO and CO in the second product stream to solid carbon, wherein at least a portion of the heat released in the exothermic reaction is transferred to the first reactor.

[0092] A twenty-third aspect may include the system of the twenty-second aspect, further including a water separation unit configured to separate at least a portion of the water in the second product stream; and a hydrogen separation unit configured to separate at least a portion of the hydrogen from the second product stream, wherein the second product stream having the portion of the removed water and the portion of the removed hydrogen forms the second product stream received by the third reactor.

[0093] A twenty-fourth aspect may include the system of the twenty-second or twenty-third aspect, wherein the second reactor is configured to be heated by burning H2.

[0094] A twenty-fifth aspect may include the system of any one of the twenty-second to twenty-fourth aspects, wherein the hydrocarbons include methane, natural gas, ethanol, naphtha, crude oil, biomass, or any combination thereof.

[0095] A twenty-sixth aspect may include the system of any one of the twenty-second to twenty-fifth aspects, wherein the first reactor, the second reactor, and the third reactor are each configured to operate at a pressure of 1 to 50 bar or about 5 to 20 bar.

[0096] A 27th aspect may include the system of any one of the 22nd to 26th aspects, wherein the first reactor and the second reactor are each configured to operate at a different pressure than the third reactor.

[0097] A 28th aspect may include the system according to any one of the 22nd to 27th aspects, wherein the first reactor and the second reactor are configured to operate at a temperature of 400°C to 1000°C.

[0098] A twenty-ninth aspect may include the system according to any one of the twenty-second to twenty-eighth aspects, wherein the third reactor includes a fluidized bed.

[0099] A thirtieth aspect may include the system according to any one of the twenty-second to twenty-ninth aspects, wherein the third reactor is a fluidized bed reactor containing a metal or metal carbide catalyst.

[0100] A thirty-first embodiment can include the system of the thirty-first embodiment, wherein the metal or metal carbide catalyst comprises Fe, Mn, Co, Ni, Si, Mg, Ca, Na, Al, Ti, Pt, Pd, Rh, Ru, or any combination thereof.

[0101] A thirty-second aspect may include the system of any one of the twenty-second to thirty-first aspects, wherein the first reactor, the second reactor, or both, comprise a catalyst, and the catalyst comprises Fe, Mn, Co, Ni, Si, Mg, Ca, Na, Al, Ti, Pt, Pd, Rh, Ru, or any combination thereof.

[0102] It should be further understood that this detailed description is not limited to the specific methodologies, compounds, materials, manufacturing techniques, uses, and applications described herein as they vary. It should also be understood that the terminology used herein is used for the purpose of describing particular embodiments only and is not intended to limit the scope of the present systems and methods. As used herein and in the appended claims (in this application, or any derivative thereof), it should be noted that the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, a reference to "an element" is a reference to one or more elements and includes equivalents thereof known to those skilled in the art. All conjunctions used should be understood in the most inclusive sense possible. Thus, the word "or" should be understood to have the definition of a logical "or" rather than a logical "exclusive or" definition unless the context clearly requires otherwise. Structures described herein should also be understood to refer to functional equivalents of such structures. Language that may be construed as expressing approximation should be so understood unless the context clearly dictates otherwise.

[0103] 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 to which this invention belongs. Although preferred methods, techniques, devices, and materials are described, Any methods, techniques, devices, or materials similar or equivalent to those described may be used in the practice or testing of the present systems and methods. It should be understood that structures described herein also refer to functional equivalents of such structures. The present systems and methods will now be described in detail with reference to embodiments thereof, as illustrated in the accompanying figures.

[0104] From a reading of the present disclosure, other variations and modifications will be apparent to persons skilled in the art, and may involve equivalent and other features which are already known in the art and which may be used instead of or in addition to features already described herein.

[0105] Although the claims may be formulated to a particular combination of features in the application or in this application or any further application derived therefrom, it should be understood that the scope of the disclosure also includes any novel feature or any novel combination of features disclosed herein, either explicitly or implicitly, or in any generalization thereof, whether or not it relates to the same system or method as actually claimed in any claim, and whether or not the system and method alleviates any or all of the same technical problems when implemented.

[0106] Features that are described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in a single embodiment may also be provided separately or in any suitable subcombination. Applicant hereby notifies that new claims may be formulated to such features and / or combinations of features upon prosecution of this application or any further application derived therefrom.

Claims

1. 1. A heat-integrated reaction process comprising: Carrying out one or more exothermic reactions to produce heat and CO, hydrocarbons, and CO ２ forming solid carbon from a reactant gas comprising: transferring at least a portion of the heat from the one or more exothermic reactions to at least one endothermic reaction of the one or more endothermic reactions; and using the heat from the one or more exothermic reactions to carry out the one or more endothermic reactions. The process comprising:

2. 10. The process of claim 1, wherein the one or more exothermic reactions comprises a CO reduction reaction.

3. 10. The process of claim 1, wherein the one or more exothermic reactions comprises a Boudouard reaction.

4. The one or more exothermic reactions ２ 10. The process of claim 1, comprising a reduction reaction.

5. The one or more exothermic reactions ２ reacts with CO, CO ２ , and H ２ 10. The process of claim 1, comprising a hydrocarbon in combination with an O-containing gaseous species to form said solid carbon.

6. 10. The process of claim 1, wherein the one or more exothermic reactions occur in a fluidized bed containing solid carbon, metal, metal oxide, and / or metal carbide.

7. 7. The process of claim 6, wherein the metal of the metal, metal oxide, and / or metal carbide comprises at least one of Fe, Mn, Co, Ni, Si, Mg, Ca, Na, Al, Ti, Pt, Pd, Rh, Ru, or any combination thereof.

8. 10. The process of claim 1, wherein the one or more endothermic reactions comprises a steam methane reforming reaction.

9. 10. The process of claim 1, wherein the one or more endothermic reactions comprises a dry reforming of methane reaction.

10. The process of claim 1 , wherein the one or more endothermic reactions comprise a hydrocarbon pyrolysis reaction.

11. 10. The process of claim 1, wherein the one or more endothermic reactions comprises a reverse water gas shift reaction.

12. 10. The process of claim 1, wherein the one or more endothermic reactions comprises a steam gasification of carbon reaction.

13. 10. The process of claim 1, wherein the one or more endothermic reactions comprises a reverse Boudouard reaction.

14. 10. The process of claim 1, wherein the one or more exothermic reactions occur at a temperature of 400 to 1000°C.

15. 10. The process of claim 1, wherein the one or more exothermic reactions occur at a pressure of about 1 to 50 bar.

16. 10. The process of claim 1, wherein the one or more endothermic reactions occur at a pressure of about 1 to 50 bar.

17. 10. The process of claim 1, wherein the one or more endothermic reactions occur at a pressure above the pressure at which the one or more exothermic reactions occur.

18. 10. The process of claim 1, wherein the one or more endothermic reactions occur at a pressure that is less than the pressure at which the one or more exothermic reactions occur.

19. 10. The process of claim 1, wherein the one or more endothermic reactions occur at about the same pressure as the one or more exothermic reactions.

20. 10. The process of claim 1, wherein said transferring heat to said at least one endothermic reaction occurs in an exothermic reactor carrying out said one or more exothermic reactions.

21. 10. The process of claim 1, wherein said transferring heat to said at least one endothermic reaction occurs outside an exothermic reactor carrying out said one or more exothermic reactions.

22. 1. A system for converting hydrocarbons into solid carbon and hydrogen, comprising: The hydrocarbon is ２ O and / or CO ２ By CO, CO ２ , H ２ O and H ２ a first reactor configured to at least partially convert the reactant gas into a first product stream comprising: a second reactor configured to receive the first product stream and further convert the first product stream to produce a second product stream; and receiving said second product stream and conducting an exothermic reaction to generate CO and CO in said second product stream; ２ a third reactor configured to convert at least a portion of the carbon dioxide gas into solid carbon, wherein at least a portion of the heat released in the exothermic reaction is transferred to the first reactor.

23. a water separation unit configured to separate at least a portion of the water in the second product stream; and a hydrogen separation unit configured to separate at least a portion of the hydrogen from the second product stream. wherein the second product stream having a portion of the water removed and a portion of the hydrogen removed forms the second product stream received by the third reactor.

24. The second reactor is ２ 23. The system of claim 22, wherein the system is configured to be heated by burning

25. 23. The system of claim 22, wherein the hydrocarbons comprise methane, natural gas, ethanol, naphtha, crude oil, biomass, or any combination thereof.

26. 23. The system of claim 22, wherein the first reactor, the second reactor, and the third reactor are each configured to operate at a pressure of 1 to 50 bar or about 5 to 20 bar.

27. 23. The system of claim 22, wherein the first reactor and the second reactor are each configured to operate at a different pressure than the third reactor.

28. 23. The system of claim 22, wherein the first reactor and the second reactor are configured to operate at a temperature between 400°C and 1000°C.

29. 23. The system of claim 22, wherein the third reactor comprises a fluidized bed.

30. 23. The system of claim 22, wherein the third reactor is a fluidized bed reactor containing a metal or metal carbide catalyst.

31. 31. The system of claim 30, wherein the metal or metal carbide catalyst comprises Fe, Mn, Co, Ni, Si, Mg, Ca, Na, Al, Ti, Pt, Pd, Rh, Ru, or any combination thereof.

32. 23. The system of claim 22, wherein the first reactor, the second reactor, or both, comprises a catalyst, the catalyst comprising Fe, Mn, Co, Ni, Si, Mg, Ca, Na, Al, Ti, Pt, Pd, Rh, Ru, or any combination thereof.

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