Reactors including self-cleaning rotating elements, and associated systems, devices, and methods

Abstract

To provide systems and methods for handling solid carbon buildup of carbon products or by-products in a chemical reactor.SOLUTION: Embodiments include a pyrolysis reactor comprising a rotating element including a first surface and a second surface, wherein, in operation, the first surface and / or the second surface is positioned to receive solid carbon, resulting in carbon buildup on the first surface and / or the second surface, and as the rotating element rotates, the first surface and / or the second surface is configured to remove at least a portion of the carbon buildup. Some embodiments include a pyrolysis system comprising a pyrolysis reactor, a regeneration oxidizer feed, and a mechanical removal mechanism. Some embodiments include a pyrolysis reactor comprising a first rotating tube including an outer surface, a second rotating tube including an inner surface, and a pyrolysis chamber between the outer surface and the inner surface, wherein rotation of the first rotating tube and the second rotating tube is configured to remove carbon buildup.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] (Related Applications) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 647,548, filed May 14, 2024, the entire contents of which are incorporated herein by reference.

[0002] FIELD OF THE INVENTION The present disclosure relates generally to reactors and reactor cleaning. More particularly, the present disclosure relates to pyrolysis reactors, regenerative pyrolysis reactors, and self-cleaning rotating elements of reactors configured to remove solid carbon products. [Background technology]

[0003] Certain chemical reactions produce solid carbon products or co-products from gaseous or liquid precursors. An example of such a reaction is a pyrolysis reaction. In the pyrolysis of hydrocarbons (e.g., natural gas, methane, propane, and / or other suitable hydrocarbons), the hydrocarbons dissociate into hydrogen gas (H) and solid carbon (C). For example, methane pyrolysis splits methane into hydrogen and solid carbon (CH → C + H). Other examples of chemical reactions that produce solid carbon products or co-products from gaseous or liquid precursors include propane pyrolysis, ethylene cracking, and dry reforming of methane, each of which can commonly encounter problems with coking and carbon buildup. Removing and cleaning this solid buildup so that chemical reactors can operate continuously without clogging presents significant design challenges. Solid deposition occurs both due to the accumulation of particles generated in gas-phase reactions and due to direct deposition reactions on hot surfaces (e.g., via chemical vapor deposition (CVD)). Therefore, there is a need in the art for a system and method for treating solid deposits of carbon products or co-products.

[0004] In addition to the design challenges of operating chemical reactors continuously without clogging, there are additional design challenges due to the nature of the chemical reactions that produce solid carbon products or co-products from gaseous or liquid precursors. For example, pyrolysis reactors can have very high operating temperatures, which can limit the types of components that can be used in the reactor (because the components must operate at high operating temperatures), cause wear on the components and the reactor, and make it difficult to operate the reactor continuously. Summary of the Invention

[0005] Generally, the present disclosure relates to reactors and reactor cleaning, and more particularly, to pyrolysis reactors, pyrolysis reactor regeneration, and self-cleaning rotating elements for pyrolysis reactors configured to remove solid carbon products. In one example, the present disclosure includes a pyrolysis reactor configured to generate a product stream from a system feed, the system feed including a hydrocarbon reactant, and the product stream including hydrogen gas and solid carbon. The reactor may include a rotating element including a first surface. The reactor may also include a second surface spaced a predetermined distance or less from the first surface, wherein during operation, the first surface and / or the second surface are positioned to receive solid carbon, resulting in carbon buildup on the first surface and / or the second surface, and the first surface and / or the second surface are configured to remove at least a portion of the carbon buildup as the rotating element rotates.

[0006] In another example, the present disclosure includes a thermal decomposition system. The thermal decomposition system may include a thermal decomposition reactor including a thermal decomposition chamber configured to generate a product stream from a system feed, the system feed including a hydrocarbon reactant, and the product stream including hydrogen gas and solid carbon. The thermal decomposition system may also include a regenerative oxidant feed, the thermal decomposition reactor configured to react the regenerative oxidant with carbon accumulation in the thermal decomposition chamber to generate a regenerated product stream output from the thermal decomposition reactor, the regenerative oxidant feed configured to remove a first portion of the carbon accumulation through oxidation. The thermal decomposition system may also include a mechanical removal mechanism configured to remove a second portion of the carbon accumulation.

[0007] In another example, the present disclosure includes a pyrolysis reactor configured to generate a product stream from a system feed, the system feed including a hydrocarbon reactant, and the product stream including hydrogen gas and solid carbon. The reactor may include a first rotary tube including an outer surface. The reactor may also include a second rotary tube including an inner surface, the first and second rotary tubes being coaxial and non-concentric. The reactor may also include a pyrolysis chamber between the outer surface of the first rotary tube and the inner surface of the second rotary tube, and pyrolysis of the system feed is configured to occur within the pyrolysis chamber. During operation, the first rotary tube is positioned to receive solid carbon that accumulates on the outer surface, and the second rotary tube is positioned to receive solid carbon that accumulates on the inner surface, resulting in carbon buildup on the outer and inner surfaces, and rotation of the first and second rotary tubes is configured to remove at least a portion of the carbon buildup.

[0008] The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will become apparent from the description and drawings, and from the claims. [Brief explanation of the drawings]

[0009] The following drawings illustrate certain embodiments of the present invention and, therefore, do not limit the scope of the invention. The drawings are not necessarily to scale (unless so noted) and are intended for use in conjunction with the explanations in the following detailed description. Embodiments of the present invention are hereinafter described in conjunction with the accompanying drawings, in which like numerals represent like elements.

[0010] [Figure 1] FIG. 1 is a schematic diagram of a reactor including a rotating element positioned to receive a solid product, according to one embodiment. [Figure 2] FIG. 1 is a schematic diagram of a reactor including multiple rotating elements positioned to receive a solid product, according to one embodiment. [Figure 3A] 1A-1C are schematic diagrams of rotating elements having various shapes, according to one embodiment. [Figure 3B] 1A-1C are schematic diagrams of rotating elements having various shapes, according to one embodiment. [Figure 3C] 1A-1C are schematic diagrams of rotating elements having various shapes, according to one embodiment. [Figure 3D] 1A-1C are schematic diagrams of rotating elements having various shapes, according to one embodiment. [Figure 3E] 1A-1C are schematic diagrams of rotating elements having various shapes, according to one embodiment. [Figure 4A] 1A-1C are schematic diagrams of cylindrical rotating elements having various shapes, according to one embodiment. [Figure 4B] 1A-1C are schematic diagrams of cylindrical rotating elements having various shapes, according to one embodiment. [Figure 4C] 1A-1C are schematic diagrams of cylindrical rotating elements having various shapes, according to one embodiment. [Figure 4D] 1A-1C are schematic diagrams of cylindrical rotating elements having various shapes, according to one embodiment. [Figure 4E] 1A-1C are schematic diagrams of cylindrical rotating elements having various shapes, according to one embodiment. [Figure 5A] 1A-1C are schematic diagrams of cylindrical rotating elements with various shapes within a housing, according to one embodiment. [Figure 5B] 1A-1C are schematic diagrams of cylindrical rotating elements with various shapes within a housing, according to one embodiment. [Figure 5C] 1A-1C are schematic diagrams of cylindrical rotating elements with various shapes within a housing, according to one embodiment. [Figure 5D] 1A-1C are schematic diagrams of cylindrical rotating elements with various shapes within a housing, according to one embodiment. [Figure 5E] 1A-1C are schematic diagrams of cylindrical rotating elements with various shapes within a housing, according to one embodiment. [Figure 6A] 1A-1C are different views of a schematic diagram of a helical rotating element, according to one embodiment. [Figure 6B] 1A-1C are different views of a schematic diagram of a helical rotating element, according to one embodiment. [Figure 7]1 is a plot of experimental data illustrating torque increase over time during reactor operation, according to one embodiment. [Figure 8A] 1A-1C are different views of a schematic diagram of a reactor including a rotating element positioned to receive a carbon product, according to one embodiment. [Figure 8B] 1A-1C are different views of a schematic diagram of a reactor including a rotating element positioned to receive a carbon product, according to one embodiment. [Figure 9A] FIG. 2 is a schematic diagram of rotating elements and various heat sources relative to the rotating elements, according to one embodiment. [Figure 9B] FIG. 2 is a schematic diagram of rotating elements and various heat sources relative to the rotating elements, according to one embodiment. [Figure 10] FIG. 1 is a flow diagram of a method for removing solid products produced in a reactor, according to one embodiment. [Figure 11] FIG. 1 is a schematic diagram of a pyrolysis system with regeneration, according to one embodiment. [Figure 12] FIG. 1 is a schematic diagram of a countercurrent pyrolysis system, according to one embodiment. [Figure 13] FIG. 1 is a schematic diagram of a pyrolysis system with regeneration, according to one embodiment. [Figure 14] FIG. 1 is a schematic diagram of a pyrolysis system with regeneration, according to one embodiment. [Figure 15] FIG. 1 is a schematic diagram showing the exterior of a pyrolysis reactor, according to one embodiment. [Figure 16] FIG. 16 is a simplified cross-sectional schematic diagram of the pyrolysis reactor of FIG. 15, according to one embodiment. [Figure 17] FIG. 1 is a simplified schematic diagram of a reactor having a two-tube arrangement, according to one embodiment. [Figure 18] FIG. 18 is a simplified schematic diagram of the reactor of FIG. 17 with a heat source, according to one embodiment. [Figure 19] FIG. 1 is a schematic diagram of an array of reactors, according to one embodiment. [Figure 20A] FIG. 1 is a schematic diagram of a metal end adapter assembly, according to one embodiment. [Figure 20B]FIG. 1 is a schematic diagram of a metal end adapter assembly, according to one embodiment. [Figure 21] FIG. 1 is a schematic diagram of a reaction load within a region of a reactor, according to one embodiment. [Figure 22] FIG. 1 is a free body diagram of a counter-rotating two-tube reactor, according to one embodiment. [Figure 23] FIG. 1 is a flow diagram of a method for removing carbon buildup from a reactor, according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following detailed description is exemplary in nature and is not intended to limit the scope, applicability, or configuration of the present invention in any way. Rather, the following description provides some practical illustrations for implementing exemplary embodiments of the present invention. Examples of configurations, materials, dimensions, and manufacturing processes are provided for selected elements, while all other elements use elements known to those skilled in the art of the present invention. Those skilled in the art will recognize that many of the described embodiments have various suitable alternatives.

[0012] A pyrolysis reactor heats hydrocarbon reactants (e.g., methane, natural gas, ethane, propane, butane, pentane, gasoline, diesel, kerosene, and / or the like) and breaks them down into hydrogen gas, solid carbon, and various products. For example, a pyrolysis reactor may crack the methane, ethane, propane, and other hydrocarbon components in natural gas to produce hydrogen gas. In the example of methane, the pyrolysis reaction is CH4 (gas) → C (solid) + 2 H2 (gas).

[0013] The hydrogen gas co-product (H) may substitute as fuel wherever natural gas would have been used. For example, the hydrogen gas may be consumed by various heating units (e.g., furnaces, hot water heaters, water heaters, steam boilers, etc.), combustion engines, fuel cells and / or generators (e.g., backup generators), combined heat and power systems, cooking units (e.g., gas stoves), and / or various other suitable applications. Additionally or alternatively, the hydrogen may be used in various industrial processes, such as the production of various ammonia-based products (e.g., ammonia fertilizer), providing process heat, and / or other chemical processing industries, and / or may be injected back into natural gas pipelines to partially decarbonize the natural gas in the pipeline. Meanwhile, the carbon co-product may be sequestered and / or utilized to decarbonize natural gas consumption. In some embodiments, the carbon co-product is sequestered by incorporating the carbon co-product into various carbon-containing products. By way of example only, the carbon co-product may supplement bitumen (or other binders) in asphalt and / or other paving products.

[0014] Pyrolysis systems may implement pyrolysis reactions to crack hydrocarbons (e.g., natural gas, pure methane, ethane, propane, butane, and / or other suitable hydrocarbons) into hydrogen gas and solid carbon. Examples of suitable pyrolysis systems are described in U.S. Non-Provisional Patent Application No. 17 / 337,326, filed June 2, 2021 (now published as U.S. Patent Application No. 11,897,768), U.S. Non-Provisional Patent Application No. 17 / 832,516, filed June 4, 2021 (now published as U.S. Patent Application Publication No. 2022 / 0387952), U.S. Non-Provisional Patent Application No. 17 / 503,187, filed October 15, 2021 (now published as U.S. Patent Application Publication No. 2022 / 0387952), and U.S. Non-Provisional Patent Application No. 17 / 503,187, filed October 15, 2021 (now published as U.S. Patent Application Publication No. 2022 / 0387952). No. 022 / 0120217, U.S. Nonprovisional Patent Application No. 17 / 710,810, filed March 3, 2022 (now published as U.S. Patent Application Publication No. 2022 / 0315424), U.S. Provisional Patent Application No. 63 / 592,904, filed October 24, 2023, and U.S. Provisional Patent Application No. 63 / 592,906, filed October 24, 2023, each of which is incorporated by reference herein in its entirety.

[0015] It is desirable to have continuous and / or near-continuous operation of the pyrolysis reactor because the machine has more uptime, which increases production of products including hydrogen gas and reduces the cost of the hydrogen produced due to the increased uptime and production. Furthermore, because hydrogen gas has numerous uses (described herein), including being recycled to the system, substituting as a fuel, and further increasing hydrogen production, it may allow more hydrogen gas to be used in these various applications, often as a more environmentally friendly alternative to other less environmentally friendly gases (e.g., natural gas, etc.).

[0016] However, as previously mentioned, carbon products can accumulate over time on operating components (e.g., of a pyrolysis system). For example, carbon products can accumulate in the pyrolysis chamber portion of a pyrolysis reactor and within the pyrolysis system. Therefore, in some cases, it may be necessary to shut down the pyrolysis reactor to remove the carbon buildup. Removing and cleaning this solid buildup can result in significant downtime and maintenance costs. This challenge can be particularly difficult for applications where it is desirable to reduce the emission intensity (CO2e / kg product) of the reaction. For example, if the solid product is carbon, it can be periodically combusted with air, steam, or oxygen and liberated as carbon oxides. However, this can result in unacceptable process emissions and process interruptions. Instead of burning the residual carbon (i.e., solid carbon buildup), the solid products can be physically or mechanically removed, but this is very challenging for several reasons, including: (i) the mechanical mechanisms must be compatible with continuous operation and / or high temperatures (e.g., for methane pyrolysis), (ii) the mechanical mechanisms must be able to withstand abrasion and wear from abrasive / reactive solid particles so as not to require frequent replacement, and (iii) if the reactor has internal structures developed for heat transfer, the mechanical mechanisms must be constructed to tight tolerances. By way of example, pyrolysis reactors may have operating temperatures of about 1000°C, about 1250°C, 1500°C, and / or about 2000°C.

[0017] For example, using a removable mechanical mechanism (such as, for example, a rod-like structure) to access a high-temperature reaction chamber can present various challenges and problems. For example, the removable mechanical mechanism can break tubes (within the reactor) as it operates more violently as solid carbon buildup increases. Seals (which prevent heat and process gases from escaping the reaction chamber while the removable mechanical mechanism accesses or exits the reactor) can also fail due to their inability to withstand the high reactor temperatures, which can result in the reactor being shut down for necessary repairs. Therefore, it is desirable to have a carbon buildup removal mechanism that is entirely internal to the reactor, minimizing the need for shutdowns and repairs, while having a structure that can withstand the forces associated with mechanical carbon removal without damaging the system.

[0018] Some embodiments of the present technology attempt to mitigate the above-mentioned problems from solid carbon buildup by utilizing one or more rotating elements, and in some instances, the carbon co-product itself, to remove the carbon co-product from the reactor and / or rotating elements. In doing so, the systems and methods disclosed herein provide a removal mechanism that is compatible with the reactor's demanding thermal design (e.g., high temperature and pressure) while also protecting the underlying machinery from wear. The rotating elements are a carbon buildup removal mechanism that is entirely internal to the reactor, including carbon rubbing against other rotating elements that already comprise the reaction chamber within the reactor. In some cases, the carbon is mechanically removed by friction or wear mechanisms, including, but not limited to, adhesive wear, abrasive wear, fretting, cracking, fatigue, chipping, or gouging. Furthermore, by utilizing entirely internal elements (i.e., rotating elements) as a removal mechanism, heat may be retained within the reactor, and the entirely internal nature of the rotating elements may eliminate / prevent additional challenges, such as the challenges of seals with periodically passing removable mechanisms (discussed above). Additionally, the rotating elements can operate while the reactor is operating, thus removing carbon buildup without the need to shut down the reactor and / or system. This allows for continuous operation of the reactor for extended periods of time without the need to turn off the system to clean the reaction chamber. Some embodiments of the technology utilize a regenerative oxidant, instead of or in addition to the rotating elements, to react with carbon products / buildup within the reactor's pyrolysis chamber and remove a portion of the carbon from the chamber.

[0019] In some embodiments, the systems and / or reactors described herein may include a rotating element comprising a first surface and a second surface spaced from the first surface by no more than a predetermined distance. The second surface may be a stationary surface or an outer surface of another rotating element. During operation, the rotating element is positioned to receive solid product that accumulates on the first surface while the rotating element rotates. Additionally, during operation, at least a portion of the solid product is removed via interaction (e.g., rubbing, scraping, and / or the like) with the second surface or solid product accumulated on the second surface as the rotating element rotates.

[0020] Embodiments of the technology may be used in a variety of applications and industries, including any application that produces a solid product on an element whose removal is desired. Particular applications may include chemical or pyrolysis reactors that produce hydrogen, acetylene, or other hydrocarbon species via the thermal decomposition of methane, natural gas, biogas, renewable natural gas, oil, or other hydrocarbons, and also produce carbon or other solid-state materials as co-products. Other applications include those that produce or use carbon as a primary product and / or those that involve grinding or polishing to produce desired properties in the resulting carbon particles. As an example, a system may use this technology to both synthesize graphite particles and spheroidize them in one step for lithium-ion battery applications. Yet another application may include stirring or agitating chemical reactors (e.g., plug flow reactors, fluidized bed reactors, etc.), which actively form and / or deposit solid materials (e.g., on rotating elements therein) that could clog the reactor.

[0021] 1 is a schematic diagram of a reactor or system 100 (herein referred to as reactor 100) including rotating elements 105 positioned to receive a solid product, according to one embodiment. Reactor 100 may include any reactor that produces a solid product that is deposited on the rotating elements of reactor 100. Additionally or alternatively, the solid product may include carbon (e.g., graphite or amorphous carbon), titanium oxide, or silicon dioxide. In some embodiments, reactor 100 may be a pyrolysis reactor and / or may be configured to receive a feed (e.g., hydrocarbons, methane, propane, natural gas, biogas, oil, mixtures thereof, etc.) and produce products (e.g., hydrogen, acetylene, and / or other hydrocarbon species) in addition to a solid product (e.g., solid carbon) and other partially reacted by-products.

[0022] 1, reactor 100 can include a rotating element 105 having an exterior surface 107 (e.g., a substrate or first surface) and a surface 110 (e.g., a second surface) spaced a predetermined distance D1 or less from exterior surface 107. In the case of a pyrolysis reactor, rotating element 105 can be located in a pyrolysis and / or heating zone and can be exposed to temperatures of at least 500 degrees Celsius (°C), 750°C, 1000°C, 1250°C, 1500°C, 2000°C, and / or in the range of 500-2000°C (or any range therebetween), and pressures of at least 0 barg, 1 barg, 2 barg, 3 barg, 4 barg, 5 barg, 10 barg, 15 barg, and / or in the range of 0-15 barg (or any range therebetween) and / or at least 1 bar, 2 bar, 3 bar, 4 bar, 5 bar, 10 bar, 15 bar (or any range therebetween). In some embodiments, D1 can be tailored to the type of reactor and / or the primary product being produced (e.g., hydrogen, acetylene, etc.), and in some embodiments, can be equal to or less than 500 millimeters (mm), 400 mm, 300 mm, 200 mm, 100 mm, 90 mm, 80 mm, 70 mm, 60 mm, 50 mm, 40 mm, 30 mm, 20 mm, 10 mm, 5 mm, 1 mm, 0.5 mm, and / or any range therebetween (e.g., 0.5 to 500 mm, 13 to 450 mm, etc.). In some embodiments, the predetermined distance can be movable (e.g., bringing the first surface and the second surface into contact with each other and removing the contact). The rotating element 105 may include or be coupled to other rotational components such as rotors, motors, gears, and the like, and may be configured to rotate clockwise or counterclockwise about an axis at an average speed of at least 0.1 revolutions per minute (RPM), 1 RPM, 5 RPM, 10 RPM, 100 RPM, 250 RPM, 500 RPM, 1000 RPM, and / or in the range of 1-1000 RPM (or any range therebetween). The rotating element 105 is positioned to receive solid product produced via the reaction supported by the reactor 100, such that as the rotating element 105 rotates, a buildup 108 of solid product (e.g., solid carbon, etc.) forms on the outer surface 107.Solid product accumulation 108 may be greater than D1 and equal to distance D2, which defines the effective boundary between the rotating element and the solid product during steady-state operation. The solid product may be deposited on exterior surface 107 (referred to herein as product deposition 112) via any number of processes, including, but not limited to, chemical vapor deposition (CVD). Deposition 112 may be uniform across the surface of rotating element 105, or may be non-uniform and / or directional. Rotating element 105 may be positioned horizontally, vertically, or at any angle between horizontal and vertical. In some embodiments, rotating element 105 is hollow and configured to receive gases or fluids used within reactor 100 (e.g., to preheat received gases to help improve the efficiency of reactor 100 and / or to combust received gases to provide heat to drive chemical reactions).

[0023] The rotating element 105 may be cylindrical, as shown in FIG. 1 , and / or may have a circular shape, or any other shape disclosed herein. In some embodiments, the rotating element 105 may include ceramic, metal, carbon-based material, composite material, and / or mixtures thereof. Ceramics may include silicon carbide, aluminum oxide, silicon nitride, boron nitride, aluminum nitride, zirconium oxide, mullite, titanium nitride, magnesium oxide, cordierite, all various compositions and stoichiometries thereof, and / or mixtures or coatings thereof. Metals may include tungsten, molybdenum, niobium, iron-chromium-aluminum alloy, steel, nickel, nickel-chromium alloy, iron-nickel-cobalt alloy, platinum, and / or mixtures or coatings thereof. Additionally or alternatively, metals may be coated with ceramic materials, or ceramics may be coated with metallic materials. Carbon-based materials may include graphite or composite materials designed for high-temperature operation, such as carbon / carbon (C / C) or carbon / silicon carbide (C / SiC) composites. Rotating element 105 may also include other materials configured to operate at the relevant reaction conditions (e.g., high temperatures and pressures) while being subjected to various forces within chemical reactor 100 and / or exhibiting chemical compatibility with the process. In some embodiments, rotating element 105 may be a rotating tube 105 within reactor 100, as further described herein.

[0024] In some embodiments, the rotating elements 105 may include a catalytic material. Advantageously, utilizing rotating elements 105 in the reactor 100 that include a catalytic material and / or are catalytic to the reaction may effectively remove and / or clean any solid-state material / products (such as buildup 108) that form on the catalyst surface during operation. Thus, in some embodiments, the catalyst or catalytic material can remain exposed to the reactants and continue to function, which is more effective compared to other catalytic rotating elements that become coated or unexposed and therefore ineffective over time. The catalytic material may include nickel, copper, tungsten, molybdenum, rubidium, platinum, iron, manganese, zinc, tin, carbon, zeolite, vanadium, oxides, and / or mixtures thereof.

[0025] During operation, as the rotating element 105 rotates, the solid product accumulation 108 contacts the second surface 110, causing a portion of the solid product to be removed (e.g., scraped) from the rotating element 105 as removed product 114 and directed elsewhere (e.g., to a collection vessel, etc.). In doing so, the effective boundary or amount of product accumulation 108 on the outer surface 107 decreases from distance D2 to distance D1. In some embodiments, as described further herein, the second surface 110 may be another surface and / or component within the reactor, such as, for example, a second tube. As more product accumulates on the outer surface 107 (via product deposition 112), and as the rotating element 105 rotates and reactions occur within the reactor 100, the effective boundary or amount of product accumulation 108 on the outer surface 107 increases from distance D1 to distance D2. This product accumulation 108 and removal 114 may continue throughout operation of the reactor 100.

[0026] Embodiments of the present technology, such as that shown in FIG. 1 , have several advantages over related conventional technologies or mechanisms for removing solid products (e.g., removed products 114) from a reactor. For example, by scraping the solid product off the rotating elements 105 without touching the outer surfaces 107 themselves, the outer surfaces 107 do not wear out, last longer, and have shorter maintenance intervals. Furthermore, because a portion of the solid product may remain coated on the outer surfaces of the rotating elements 105, the rotating elements 105 may be protected from abrasion and other mechanical wear, thereby improving the operating lifecycle of the rotating elements 105. Relatedly, because the operation of the rotating elements 105 can remove the solid product (i.e., removed products 114) without additional components, there may be more design space and flexibility for possible reactor geometries compared to other carbon removal methods. Additionally, or alternatively, because the removal mechanisms for embodiments of the present technology are less prone to clogging and may not require space for additional mechanical removal machinery, the diameter and / or cross-sectional dimensions of the rotating elements 105 may be reduced, thereby improving heat transfer. Relatedly, the smaller dimensions of the rotating element 105 may also allow any external machinery (e.g., gears, motors, etc.) required to drive the rotating element 105 to be more compact, thus enabling further design options. As another example, a buildup of solid material (e.g., buildup 108) on a rotating element (e.g., rotating element 105) narrows the channels between the outer surface (e.g., outer surface 107) of the rotating element and an adjacent surface (e.g., second surface 110, which in the illustrative case may be the surface of another rotating element). In doing so, gas flow through or around these channels has a higher velocity and / or a smaller hydraulic diameter, which generally can result in improved heat transfer between the gas and the corresponding surface, improving pyrolysis. These high-aspect-ratio channels may be difficult to form by machining or manufacturing. As yet another example, the rotating element 105 may use only rotary seals, which generally last longer than other seals (e.g., linear seals and / or linear and rotary seals).

[0027] FIG. 2 is a schematic diagram of a reactor 200 including multiple rotating elements 105 and 205 positioned to receive a solid product, according to one embodiment. Reactor 200 may include all of the features and functionality described and illustrated with respect to reactor 100 of FIG. 1 . As shown in FIG. 2 , reactor 200 may include rotating element 105 and an exterior surface 107 positioned to receive a solid product / solid carbon (e.g., through product pile 112), as described in FIG. 1 . Reactor 200 may also include a second rotating element 205 including an exterior surface 207 (e.g., second surface 110 of FIG. 1 ) positioned to receive a solid product / solid carbon (e.g., through product pile 212). Second rotating element 205 may include all of the features and functionality described and illustrated with respect to reactor 100 of FIG. 1 . As shown in FIG. 2 , exterior surface 107 of rotating element 105 may be spaced apart from exterior surface 207 of second rotating element 205 by a distance D1 or less, as previously described. In some embodiments, the rotating elements 105, 205 may have the same shape and the same cross-sectional dimensions, as shown in Figure 2. In some embodiments, the cross-sectional dimensions of the rotating elements 105, 205 may differ from one another.

[0028] In some embodiments, reactor 200 may include more than two rotating elements (e.g., three, four, five, ten, etc.), each of which may include similar features and / or unique features that are different from the other rotating elements. For example, the rotating elements may have different sizes and / or cross-sectional dimensions, different shapes, different clearances to adjacent surfaces, and / or different rotational speeds. Additionally or alternatively, the angular velocity of the rotating elements may not be constant. For example, periodically stopping, pausing, and restarting rotation may aid in material removal. In this regard, the design of reactor 200, or more specifically the design of the rotating elements and their arrangement, may be based on a desired end use or application.

[0029] During operation, as the rotating elements 105, 205 rotate, the solid product (e.g., solid carbon) buildup 108 on the exterior surface 107 contacts the solid product buildup 208 on the exterior surface 207, causing a portion of the solid product buildup 108, 208 on each of the exterior surfaces 107, 207 to be removed (e.g., scraped) from the rotating elements 105, 205 as removed product 114 and directed elsewhere (e.g., to a collection container). In doing so, the effective boundary or volume of the product buildup 108, 208 on the exterior surfaces 107, 207 decreases. As the rotating elements 105, 205 rotate and reaction occurs within the reactor 200, more product (e.g., carbon) deposits 112, 212 on the exterior surfaces 107, 207, and the effective boundary or volume of the product buildup 108, 208 on the exterior surfaces 107, 207 increases. This product accumulation (e.g., product accumulations 108 , 208 ) and removal (e.g., removed product 114 ) may continue throughout operation of reactor 200 .

[0030] The advantages discussed with reference to reactor 100 also apply to reactor 200. Furthermore, because the product reservoirs 108, 208 for each of the rotating elements 105, 205 are the only materials that contact and remove the product, there is no wear on any fixed surfaces of the equipment, thereby requiring even less maintenance and further increasing the uptime of reactor 200.

[0031] 3A-3E are schematic cross-sectional views of rotating element structures 300 having various shapes, according to some embodiments. In some embodiments, as shown in FIGS. 3A-3E, the rotating element structure 300 can include multiple rotating elements 305. The rotating elements 305 and rotating element structure 300 in FIGS. 3A-3E can include any of the features and functionality described and illustrated with respect to the rotating elements 105, 205 in FIGS. 1 and 2. FIG. 3A includes two rotating elements 305a and 305b (collectively referred to as 305), each having a bilobal, oval shape with two curved sides 304a, 304b (collectively referred to as 304) joining at end points (tips) 306a, 306b (collectively referred to as 306). The tip 306 of the shape can have a width (e.g., tip angle) that includes a tip angle (e.g., point) of 0. The cross-sectional dimension 316 of the individual rotating elements decreases circumferentially. As shown, in a configuration such as rotating element structure 300 shown in FIG. 3A, the orientations of rotating elements 305 can differ by approximately 90 degrees. For example, the orientation of rotating element 305a can differ by approximately 90 degrees from the orientation of rotating element 305b, and vice versa.

[0032] FIG. 3B includes a rotating element 305 similar to the rotating element of FIG. 3A, but is a trilobe with three tips arranged as three rotating elements 305a, 305b, and 305c. Each rotating element 305 in FIG. 3B can have an orientation that differs by 90 degrees from the rotating elements 305 that it is contacting. For example, rotating element 305a can be in contact with rotating elements 305b and 305c, and thus, rotating element 305a can have an orientation that differs by 90 degrees from both rotating element 305b and rotating element 305c. In the example shown in FIG. 3B, rotating elements 305b and 305c each contact (or at least nearly contact) only rotating element 305a, and therefore, rotating elements 305b and 305c can have an orientation that differs by 90 degrees from rotating element 305a, but need not have an orientation that differs by 90 degrees from each other. Thus, as shown in FIG. 3B, rotating elements 305b and 305c can have the same and / or similar orientations.

[0033] Figure 3C includes three rotating elements 305a, 305b, and 305c (collectively referred to as 305) having a triangular shape with curved sides 304a, 304b, and 304c (collectively referred to as 304) connecting at endpoints 306a, 306b, and 306c (collectively referred to as 306). Figure 3D includes four rotating elements 305a-d having the same / similar shape as rotating element 305 of Figures 3A and 3B. Figure 3E includes 16 rotating elements 305a-p having the same / similar shape as rotating element 305 of Figures 3A and 3B. Embodiments of the technology can include any number of rotating elements (e.g., 4, 5, 6, 7, 8, 10, 20, etc.) and patterns described herein, as well as any shape (e.g., bilobal, trilobal, multilobal, etc.). In some embodiments, the rotating shapes / elements 305 are constructed through specific geometries to create a self-cleaning effect for non-circular shapes. For example, for each number of leaves and for a given center-to-center distance, a shape can be constructed from connected arcs such that every point on the surface of a first element 305 is cleaned by the tip of another rotating element 305 during co-rotation. Additionally or alternatively, the outer housing of the reactor can be constructed from a union of enclosing circles surrounding the array of rotating elements such that the reactor walls are also thoroughly cleaned.

[0034] 4A-4E show schematic diagrams of rotating element structures 400 having cylindrical rotating elements 405 with various shapes, according to some embodiments. The rotating elements of FIGS. 4A-4E can include any of the features and functionality described and illustrated with respect to rotating elements 105, 205 of FIGS. 1 and 2 and rotating element 305 of FIGS. 3A-3E. Rotating element structure 400 of FIG. 4A includes two cylindrical rotating elements 405a, 405b similar to those described with respect to FIG. 2. FIGS. 4B, 4C, and 4E include three (405a-c), four (405a-d), and 36 (405a-jj) cylindrical rotating elements, respectively, each having the same or similar cross-sectional dimensions.

[0035] 4D includes twelve cylindrical rotating elements 405a-l, some of which have different cross-sectional dimensions than the other rotating elements. For example, FIG. 4D shows an example structure 400 in which rotating elements 405a, 405d, 405i, and 405l all have a similar cross-sectional dimension (e.g., a first cross-sectional dimension), and rotating elements 405b, 405c, 405e, 405f, 405g, 405h, 405j, and 405k all have a similar cross-sectional dimension (e.g., a second cross-sectional dimension). However, the first cross-sectional dimension and the second cross-sectional dimension can be different from one another (e.g., the first cross-sectional dimension can be larger than the second cross-sectional dimension). Embodiments of the technology may include any number of rotating elements 405, any pattern of rotating elements 405, and any combination of cross-sectional dimensions of the rotating elements 405.

[0036] 5A-5E show schematic diagrams of a rotating element structure 500 having cylindrical rotating elements 505 with various shapes within a housing 515, according to some embodiments. The rotating elements 505 in FIGS. 5A-5E can include any of the features and functionality described and illustrated with respect to the rotating elements 105, 205, 305, 405 of FIGS. 1-4E. The rotating element structure 500 in FIG. 5A includes a rotating element 505a having an outer surface 507, which resides within an inner surface 510 of a chamber / housing 515. In some embodiments, as shown in FIG. 5A, the housing 515 and its inner surface 510 can have a shape similar to the outer surface 507 of the rotating element 505a.

[0037] 5B-5E show other examples of rotating elements 505. For example, FIG. 5B shows a structure 500 having three rotating elements 505a-c within a housing 515. FIG. 5C shows a structure 500 having five rotating elements 505a-e of the same / similar size (e.g., same / similar cross-sectional dimensions) within a housing 515. FIG. 5D shows a structure having six rotating elements 505a-f of various sizes / cross-sectional dimensions within a housing 515 (e.g., rotating element 505f has a smaller cross-sectional dimension than rotating elements 505a-e). FIG. 5E shows a structure having seven rotating elements 505a-g (e.g., of the same / similar size and cross-sectional dimensions) within a housing 515.

[0038] In some embodiments, both the inner element (i.e., rotating element 505) and the inner surface 510 of the chamber / housing 515 are rotated to create relative motion between the inner rotating element 505 and the outer surface. The rotating element 505 and the housing 515 may counter-rotate, or may co-rotate if the two have different angular velocities. In some embodiments, the inner surface 510 of the chamber / housing 515 is held fixed, and the inner rotating element 505 may further orbit within the outer housing 515.

[0039] Figure 6A is a schematic diagram of a structure 600 having twisted or helical rotating elements 605a, 605b (collectively referred to as rotating elements 605), according to some embodiments, and Figure 6B is a cross-sectional view of the rotating element 605 of Figure 6A. The rotating element 605 may include any of the features and functionality described and illustrated with respect to the rotating elements of Figures 1-5E. The shape of the rotating element 605 may be shown (in Figures 6A and 6B) as being a bilobed oval shape similar to the shape shown in Figure 3A, although the rotating element 605 may have other shapes.

[0040] In some embodiments, the shape and / or geometry of the rotating elements 605 may generally have a larger surface area than other rotating element shapes (e.g., circular) and therefore may receive and subsequently remove deposited solid product at a higher rate. Furthermore, the relative amount of interface 621 between rotating elements 605 may be larger than that of other shapes of rotating elements due to their shape and / or geometry, which may also advantageously help remove deposited solid product at a higher rate. Additionally, or alternatively, twisting the rotating elements 605 may increase the path length of gas flowing down the length of contacting rotating elements, thus increasing heat transfer. In some embodiments, such shapes (e.g., twisted and / or helical shapes) are used when the carbon deposition source 622 (or other solid deposition source) is positioned circumferentially transverse to and / or along the length of the rotating elements 605.

[0041] 7 is a plot 700 of experimental data illustrating the relationship of increasing torque over time during operation of a reactor (such as a pyrolysis reactor), according to one embodiment. Plot 700 illustrates how the torque of a motor required to rotate one or more rotating elements (e.g., rotating elements 105, 205, 305, 405, 505, and / or 605) can change from start-up to steady-state operation of the reactor (e.g., reactor 100, 200) as solid product begins to accumulate on and be removed from the exterior surfaces of the one or more rotating elements. Time T1 generally corresponds to start-up of the reactor. As reaction occurs within the reactor, solid product is produced and accumulates on the exterior surfaces of the rotating elements (e.g., the same and / or similar to product deposits 112, 212 and product deposits 108, 208 shown in FIGS. 1 and / or 2). As buildup accumulates to the point where the accumulated product begins to contact an adjacent surface (e.g., a stationary surface, accumulated product on a stationary surface, a rotating surface, or accumulated product on a rotating surface), the torque required to rotate the rotating element increases (e.g., at time T2 or any time between T1 and T3) due to friction from the accumulated product. This torque increase continues until a maximum amount of product has accumulated on the exterior surface (e.g., time T3), at which point the torque may remain generally constant with less fluctuation because the rate of material removal generally matches (or is equal to) the rate of material deposition.

[0042] Torque measurements, rotating element deflection or strain measurements, load and / or force measurements, product gas composition measurements, gas pressure measurements, elapsed time, etc. collected during operation may be used as part of a control scheme for operating the reactor. For example, measurements of the torque supplied to a rotary self-cleaning element may be used as input to a control algorithm that may recommend and / or automatically adjust operating parameters such as reactant gas input flow rate or composition, the rate of heat delivery to the reactor, and / or the temperature profile of the reactor. For example, the power supplied by or the configuration of one or more burners or resistive electric heaters may be adjusted based on the torque measurements. Additionally or alternatively, based on one or more of these measurements (such as the measurements described above, sensor feedback, time intervals, and / or other measurements), the rotational speed of one or more of the rotating elements may be adjusted, the direction of rotation may be reversed, and / or rotation may be stopped.

[0043] Figure 8A illustrates a schematic diagram of reactor 800 including rotating elements 805a, 805b, 805c (collectively referred to as rotating elements 805) positioned to receive a solid product (e.g., solid carbon), and Figure 8B is a cross-sectional view (from cross section 802) of rotating element 805 of Figure 8A, according to some embodiments. Reactor 800 and / or rotating element 805 can include any of the features described and illustrated with respect to reactors 100, 200 and rotating elements 105, 205, 305, 405, 505, and / or 605, respectively, described herein.

[0044] 8A , reactor 800 may include a heat source 815 (e.g., a furnace, burner, combustion component, resistive electric heater, and / or a device that generates an electromagnetic field to deliver energy to reactants (e.g., an induction source or microwave source), as examples) configured to provide external heat to rotating elements 805, a drive system 825 operably coupled to and configured to rotate rotating elements 805, and a controller 820 operably coupled to heat source 815 and drive system 825. Controller 820 may be coupled to other sensors and / or various components of reactor 800 and, in some examples, may adjust operation of reactor 800 based on measurements from the sensors and / or components.

[0045] FIG. 9A is a schematic diagram of a rotating element 905 of a reactor 900 and various heat sources 915a, 915b, 915c, 915d, and 915e (collectively referred to as heat sources 915) relative to the rotating element 905, according to one embodiment. FIG. 9B illustrates a schematic diagram of the rotating element 905 and its corresponding centerlines / centerpoints 906, 911 within a tube 910. In some embodiments, the tube 910 may be a pyrolysis tube 910 and / or a pyrolysis chamber 910, and the pyrolysis reaction may occur within a passageway (depicted as passageway 914) formed between the tube 910 and the rotating element 905. The passageway 914 may constitute a volume in which the pyrolysis process and / or reaction is stabilized. In some embodiments, the passageway 914 may be a crescent-shaped passageway, as shown in FIG. 9A.

[0046] As shown in Figure 9A, the rotating element 905 may be disposed within an outer tube or bounding wall 910 (referred to herein as tube 910). In some embodiments, the tube 910 is the same as and / or similar to the housing 515 shown in Figures 5A-5E. In some embodiments, as depicted in Figures 9A and 9B, the rotating element 905 is disposed within the tube 910 such that the centerlines and / or center points 906, 911 of the rotating element 905 and the tube 910 are different from one another (i.e., offset 912). Figure 9B illustrates the center point 906 of the rotating element 905, the center point 911 of the tube 910, and their offset 912.

[0047] By offsetting 912 rotating element 905 and tube 910 (and their corresponding centerlines and / or center points 906, 911), solid product accumulated on outer diameter 907 and / or outer surface 907 of inner rotating element 905 rubs against solid product accumulated on inner diameter 908 and / or inner surface 908 of outer tube 910. In this illustrative example, the rub points are shown as rub points 909. As rotating element 905 and / or tube 910 rotate, rub points 909 may move along outer surface 907 and inner surface 908. In some embodiments, outer diameter / surface 907 of rotating element 905 is the same as and / or similar to outer surface 107 (FIGS. 1 and / or 2), outer surface 207 (FIG. 2), and / or outer surface 507 (FIGS. 5A-5E). In some embodiments, the inner diameter / surface 908 of the outer tube 910 is the same as and / or similar to the second surface 110 and / or the inner surface 510 (FIGS. 5A-5E). In other embodiments, the inner tube 905 is mechanically mounted such that the linear offset 912 can also be time-varying, so that the carbon buildup is periodically brought into and out of grinding contact at point 909 to facilitate carbon removal.

[0048] During rotation of the rotating element 905, a non-zero relative surface velocity may exist, which may be achieved by rotating both the inner rotating element 905 and the outer tube 910 (e.g., in opposite directions and / or at different relative angular velocities), or by rotating and orbiting one of the rotating element 905 or tube 910 relative to a stationary tube / object. These configurations are convenient for providing heat 916 from outside the outer encasing tube 910, which may allow flexibility in the size of the heat source 915 (e.g., without having to fit within the rotating element 905).

[0049] 9, heat 916 may be provided and / or generated within rotating element 905 (e.g., via heat source 915a), which may include or be a burner, combustion component, resistive electric heater, and / or a device that generates an electromagnetic field to deliver energy to the reactants (e.g., an induction or microwave source). Heat may also be provided or generated from outside tube 910 and rotating element 905 (e.g., via heat sources 915b, 915c, 915d, and / or 915e), which may include a burner, combustion component, resistive electric heater, and / or a device that generates an electromagnetic field to deliver energy to the reactants (e.g., an induction or microwave source). In some embodiments, when reactor 900 includes multiple rotating elements 905 (not shown), some of the rotating elements 905 may be internally heated (e.g., via internal heat sources 915a), while other rotating elements 905 may not be internally heated (may not include internal heat sources 915a). Advantageously, this may reduce complexity and / or the total number of combustion and / or other heat sources.

[0050] In some embodiments, solid product deposition (e.g., product deposition 112 and / or 212) on a rotating element (e.g., 105, 205, 305, 405, 505, 605, 805, and / or 905) can depend on the local heat flux and / or temperature from a heat source (e.g., 915). For example, carbon deposition is often a function of the temperature of pyrolysis. In such embodiments, the heat flux and temperature profiles of the rotating elements (e.g., 105, 205, 305, 405, 505, 605, 805, and / or 905) can be designed to control the deposition rate of material along the length of the rotating element to homogenize the deposition rate.

[0051] Furthermore, the use of friction to remove solid product / carbon (e.g., product buildup 108 and / or 208) from rotating elements (e.g., 105, 205, 305, 405, 505, 605, 805, and / or 905) is restorative in that heat generation from friction can be used to offset thermal energy that would otherwise need to be generated by an additional heat source. The energy used in the rotary drive system (e.g., 825) is similarly used to drive the reaction through heat generation, thereby increasing system efficiency. In some embodiments, local temperatures at contact areas (e.g., interface 621, rub points 909, etc.) can be substantially higher than the reactor average temperature, creating reaction “hot spots” and increasing reactor efficiency and reactant conversion. When friction is high, it is possible to provide all the necessary reaction heat through frictional dissipation (similar to how friction stir welding works). Furthermore, frictional dissipation and the wear rate of solid products can be increased by adding abrasive particles to the reactor feedstock input. For example, a portion of the carbon particles produced may be recycled to the reactor.

[0052] In some embodiments, reactor 900 is shown as having a single rotating element 905 within outer tube 910, although there may be multiple rotating elements 905 within outer tube 910. For example, rotating elements such as rotating element 805 (FIGS. 8A and 8B) may all be within a single outer tube, such as outer tube 910. As another example, in some examples, outer tube 910 may be the same as and / or similar to housing 515 (FIGS. 5A-5E). In this illustrative case, rotating element 905 may include one or more rotating elements, such as rotating element 505 shown in FIGS. 5A-5E. In some embodiments, these one or more rotating elements within a housing / outer tube (e.g., housing 515, outer tube 910, and / or another type of outer tube) may be of different quantities and / or sizes (e.g., rotating element 405 shown in FIGS. 4A-4E) and / or different shapes (e.g., rotating element 305 shown in FIGS. 3A-3E). In some embodiments, the helical rotating element (such as rotating element 605 (FIGS. 6A-6B)) can be within a single housing / outer tube (such as housing 515, outer tube 910, and / or another type of outer tube). When there are multiple rotating elements (e.g., rotating elements 305, 405, 505, 605, 805, etc.) within an outer tube / housing, the passageway (such as passageway 914) through which the pyrolysis reaction can occur is the space between the multiple rotating elements and the outer tube. In some embodiments, the interior of each rotating element and / or one or more of the rotating elements (e.g., rotating elements 305, 405, 505, 605, 805, 905, etc.) can be a heating element and / or combustion chamber to help generate sufficient heat for the pyrolysis reaction to occur within the passageway / volume between the rotating element and the outer tube / housing. In some embodiments, one or more of the rotating elements (e.g., rotating elements 305, 405, 505, 605, 805, 905, etc.) may not include a heating element or generate heat. For example, heat generation within the rotating elements may be optional. Heat may be provided from outside the housing / outer tube, from inside the tube and / or rotating element, or both.

[0053] Reactor 900, in some examples, may be the same as and / or similar to reactor 1500. For example, outer tube 910 may be the same as and / or similar to outer tube 1620, and inner tube 1610 may be the same as and / or similar to rotating element 905. Thus, in some embodiments, while reactor 1500 is shown and described herein as having a single inner tube 1610 (e.g., the same as and / or similar to having a single inner rotating element 905), there may be multiple inner tubes 1610 and / or rotating elements of other shapes, sizes, etc. within the outer tube (e.g., outer tube 1620, as described further herein) of the reactor (e.g., reactor 1500, as described further herein). For example, in some examples, an inner tube (e.g., inner tube 1610) may actually be one or more rotating elements (e.g., rotating elements 105, 205, 305, 405, 505, 605, 805, 905, etc.) within the outer tube of the reactor.

[0054] 10 is a block flow diagram of a method 1000 for removing solid products generated in a reactor, according to one embodiment. Method 1000 may include operation 1002 of providing a chemical reactor (e.g., reactor 100, 200, 800, etc.) comprising a first rotating element (e.g., rotating element 105, 305, 405, 505, 605, 805, and / or 905) including a first outer surface (e.g., outer surface 107, 507, and / or 907) and a second surface (e.g., surface 110, outer surface 207, inner surface 510 of housing 515, and / or inner surface 908 of outer tube 910) spaced from the first outer surface by a predetermined distance (e.g., distance D1) or less. Method 1000 may further include operation 1004 of accumulating solid products (e.g., carbon) generated by a reaction (e.g., a pyrolysis reaction) in the reactor on the first outer surface. The method 1000 may further include an operation 1006 of rotating the first rotating element such that carbon products accumulated on the first exterior surface are removed directly or indirectly through the second surface. For example, the accumulated products may be removed by the second surface itself or by solid products (e.g., carbon) accumulated on the second surface.

[0055] In some embodiments, other in-situ carbon removal methods, such as mechanical mechanisms and / or fluidization and / or erosion, may not completely remove all carbon buildup / accumulation that affects pyrolysis reactor operation; therefore, these methods may require periodic removal of any residual carbon deposits by completely shutting down and / or disassembling the pyrolysis reactor and / or pyrolysis system. Furthermore, in some embodiments, carbon may accumulate faster than it can be removed. This can cause plunging cutters to stall and / or deflect into old grooves, causing scraping due to rotation, and potentially causing components to seize and / or fail due to buildup. To help prevent complete shutdown and / or disassembly of the reactor and / or to prevent carbon from accumulating faster than it can be removed through other removal processes, a regeneration process may be utilized. Regeneration and / or regeneration, as referred to herein, may include introducing regeneration gas into components (such as the pyrolysis reactor and / or pyrolysis chamber) to help regenerate the reactor (e.g., restore full functionality). The regeneration gas (also referred to herein as a regenerative oxidant) can react with the carbon to help remove the carbon deposits and / or change the carbon structural properties (which, for example, can help loosen and / or weaken the carbon) so that the carbon may be removed using one or more other removal methods. For example, to help remove carbon deposits (e.g., carbon buildup) from the reactor, the regeneration gas can include oxygen, which can then react with the carbon to oxidize and remove it from the reactor, or change the carbon structural properties to enhance removal by the methods described herein (e.g., rotating elements, other mechanical removal methods, fluidization, erosion, and / or any other removal method).

[0056] As a non-limiting example, carbon buildup may be removed by first regenerating the reactor to alter the structural characteristics of the carbon (thus facilitating removal), and then mechanically removing the carbon buildup using rotating elements (e.g., 105, 205, 305, 405, 505, 605, 805, and / or 905). In another example, carbon buildup may be removed solely by regenerating the reactor or by using rotating elements described herein (e.g., 105, 205, 305, 405, 505, 605, 805, and / or 905). In yet another example, carbon buildup may be removed by regenerating the reactor and then performing another carbon removal operation to remove any residual carbon. In yet another example, carbon buildup may be removed by performing alternative operations to modify the structural properties of the carbon and / or to make it easier to remove, and then using rotating elements (e.g., 105, 205, 305, 405, 505, 605, 805, and / or 905) to remove the carbon buildup (or at least any remaining carbon buildup).

[0057] In some embodiments, a reactor (such as a pyrolysis reactor) can have a pyrolysis mode and a regeneration mode. In the pyrolysis mode, the system (including the pyrolysis reactor) can flow a system feed into the reactor. The system feed, in some examples, can be a hydrocarbon reactant (e.g., methane, natural gas, ethane, propane, butane, pentane, gasoline, diesel, kerosene, etc.), so that when fed to the pyrolysis reactor during the pyrolysis mode, the pyrolysis reactor can heat the system feed and decompose it into hydrogen gas, solid carbon, and various products. During the regeneration mode, the system can flow / feed a regenerative oxidant into the reactor to allow the regenerative oxidant to react with carbon products / accumulation in the reactor.

[0058] In some examples, the regeneration reaction (i.e., the reaction of the regenerative oxidant with the carbon buildup) may not uniformly etch away and / or remove the carbon, but instead may create more holes in certain areas than others, creating a rougher, more porous surface within the reactor, and / or mechanically weakening the overall carbon buildup / deposition. Thus, in some embodiments, the regeneration mode may be most effective in combination with another removal process (such as the removal processes described herein). For example, if the regeneration mode roughens and / or weakens the carbon buildup, then the carbon removal method (such as plunging a cutter into the carbon, scraping the carbon against another surface (such as a rotating element), and / or any other carbon removal method) has the potential to more effectively remove the carbon buildup (compared to either the regeneration mode or the carbon removal method alone).

[0059] For example, the regeneration process / mode may be performed for a relatively short, limited period of time, i.e., a period much shorter than that required to remove all carbon. This allows the regeneration mode to be performed long enough to change the structural characteristics of the carbon without completely removing it, so that the carbon may be more easily removed using another carbon removal method. This may help prevent excessive emissions of carbon monoxide and / or carbon dioxide, since performing regeneration for a relatively short, limited period of time will emit much less carbon monoxide and / or carbon dioxide than completely removing the carbon through regeneration. Therefore, removing carbon buildup from a reactor using a combination of regeneration and another removal process may reduce emissions and be a more environmentally friendly process. Furthermore, the regeneration process may be performed for a shorter duration (since less carbon needs to be removed), thereby reducing the time spent regenerating and allowing more time to be spent performing the desired reactions in the reactor. For example, a pyrolysis reactor may have to pause pyrolysis (e.g., hydrocarbon pyrolysis) while the reactor is being regenerated. However, various other carbon removal processes (such as the rotating elements and / or other carbon removal processes described herein) can be performed while the reactor is undergoing pyrolysis. By simply regenerating for a time sufficient to change the structural characteristics of the carbon (but not long enough to completely remove the carbon from the reactor), the reactor can be paused from the pyrolysis reaction for a shorter period of time, allowing for more continuous pyrolysis and more continuous hydrogen gas generation.

[0060] Instead of or in addition to regeneration, another possible removal process may involve cooling and / or heating the carbon above its normal pyrolysis temperature and then returning it to its normal pyrolysis temperature. This causes the carbon buildup to expand and / or contract relative to the surface to which it is attached due to the different thermal expansion of different materials. This may also cause cracking and / or other deformation of the carbon, facilitating removal. In some cases, the reactor may be cooled relative to nominal operating conditions to achieve the same effect. In an exemplary embodiment, cooling and / or heating the carbon above its normal pyrolysis temperature may be combined with regeneration and / or mechanical removal processes (such as rotating elements) to help improve removal of carbon buildup within the reactor.

[0061] In some embodiments, the regenerative oxidant (i.e., the oxygen-containing regeneration gas that can react with the carbon buildup in the reactor) is an oxygen-containing component such as air, oxygen, steam, carbon dioxide, and / or another regenerative oxidant. When the regenerative oxidant is oxygen and / or air, the regeneration reaction is 2 C (solid) + O (gas) → 2 CO (gas).

[0062] If the regenerating oxidant is steam, the regeneration reaction is C(solid) + O2(gas) → H2(gas) + CO(gas).

[0063] If the regenerating oxidant is carbon dioxide, the regeneration reaction is C (solid) + CO2 (gas) → 2 CO (gas).

[0064] While regenerative oxidants and regeneration reactions are beneficial in aiding in the removal of carbon buildup, processes using oxidation chemistry in combination with carbon may produce some carbon monoxide and / or carbon dioxide in the regeneration product (also referred to herein as the regeneration exhaust), as illustrated by the exemplary reaction above. One advantage of hydrocarbon pyrolysis is its low carbon dioxide emissions compared to other methods of producing hydrogen and carbon, so mitigating these emissions is important. At the high temperatures of methane pyrolysis, the primary regeneration product (from the regeneration reaction between the regenerative oxidant and carbon) is carbon monoxide, as illustrated by the exemplary reaction above. In some instances, the reaction may be reversed in a separate process step to aid in the removal of carbon from the carbon monoxide regeneration product. For example, if the regenerative oxidant is carbon dioxide, the regeneration reaction may be reversed in a separate process step (e.g., a Boudoir reaction) to remove up to half of the carbon in the carbon monoxide regeneration product / exhaust. The reverse / reversible reaction is 2 May contain CO (gas) ⇔ CO2 (gas) + C (solid).

[0065] In some instances, when carbon dioxide is used as the regenerative oxidant, it may be possible to implement enhanced oxidation regeneration without additional system carbon dioxide emissions because the regeneration and reverse reactions are completely symmetric when carbon dioxide is the oxidant. In these cases, the carbon can be gasified from the reactor and redeposited at a different location in the system (e.g., where it is easier to remove), and the resulting carbon dioxide can be stored before the regeneration process is repeated.

[0066] 11 shows an exemplary system 1100 with regeneration capabilities, according to one embodiment. The pyrolysis system 1100 includes a reactor 1110 (e.g., a pyrolysis reactor 1110). In some embodiments, during typical operation of the reactor 1110, a system feed 1102 may be supplied to the heated reactor 1110. For example, the system feed 1102 may be a hydrocarbon reactant (e.g., methane, natural gas, ethane, propane, butane, pentane, gasoline, diesel, kerosene, etc.), and once supplied to the reactor 1110, the pyrolysis reactor 1110 may heat and decompose the system feed 1102 into hydrogen gas, solid carbon, and various products. The resulting product stream (containing at least hydrogen gas and solid carbon) may be supplied to a standard exhaust component 1118 and / or a downstream component 1118, in some examples. For example, in some instances, the product stream output from reactor 1110 may be transferred to a separator to separate the product stream components (e.g., separate carbon from hydrogen gas, separate other by-products from the product stream, etc.), and may be transferred to a heat exchanger to cool and / or heat the product stream and / or any other components, endpoints, etc. These products / product streams from pyrolysis may be referred to herein as standard products, as they are products produced by reactor 1110 during standard operation (i.e., pyrolysis).

[0067] When a pyrolysis reaction is occurring within the reactor 1110, the reactor 1110 may be in a pyrolysis mode. As described herein, the pyrolysis of the system feed 1102 (e.g., containing hydrocarbons) may result in a product stream containing hydrogen gas and solid carbon. However, over time, the solid carbon may accumulate within the reactor 1110 (e.g., along the sidewalls and / or elsewhere within the reactor 1110) and may adversely affect the performance and / or functionality of the reactor 1110 (e.g., may even clog various areas of the reactor 1110). Therefore, instead of continuously operating the system 1100 in a pyrolysis mode, as may be the standard operation of the system 1100, the system feed 1102 may be paused (thus pausing the pyrolysis mode of the system 1100 and the reactor 1110). Although it can be continuous, operating the system 1100 in pyrolysis mode all the time may result in shorter runs, and the system 1100 / reactor 1110 would need to be stopped and / or shut down periodically to clean the system 1100 or to replace coked tubes with clean ones. Therefore, in some embodiments, other means (e.g., rotating elements (described herein), other mechanical removal mechanisms, other carbon removal methods, etc.) may be used to more effectively remove carbon buildup and / or regeneration techniques / operations may be used to help remove the carbon buildup and / or to help modify the carbon structural characteristics.

[0068] In some embodiments, to regenerate the reactor 1110 (referred to herein as the regeneration mode of the reactor 1110), a regenerative oxidant 1101 (e.g., air, oxygen, steam, carbon dioxide, and / or another oxygen-containing compound) may be supplied to the reactor 1110 to react with any carbon accumulation (from the pyrolysis reaction of the system feed 1102). When the solid carbon reacts with the regenerative oxidant 1101 (and the oxygen in the regenerative oxidant 1101) at elevated temperatures, the resulting carbon monoxide and / or carbon dioxide products (referred to herein as regeneration products and / or regeneration exhaust) may exit the reactor 1110 in the gas phase. In some examples, some carbon may be removed from the reactor 1110 via the regeneration products (i.e., carbon dioxide, carbon monoxide, etc.), but the carbon accumulation may not be uniformly and / or completely removed. Instead, in these examples, the carbon may exhibit pitting, etching, cracks, other surface features, and / or other altered structural properties to weaken the solid carbon accumulation formed within the reactor 1110. The flow pattern, velocity, pressure, temperature, and / or other flow characteristics may, in some instances, be adjusted to maximize this effect and / or to preferentially remove carbon in specific areas where carbon accumulates most. In some instances, the temperature of the reactor 1110 may also be adjusted to help further maximize this effect. As an example, it may be beneficial to lower the temperature so that any gasification reactions (e.g., regeneration reactions) are selective to etching deep pores in the carbon buildup and increasing its roughness. The thermal profile and / or gas flow rates of the reactor 1110 may also, in some instances, be modified to target specific zones / locations for maximum carbon removal rates. During and / or after regeneration, mechanical removal means (such as rotating elements and / or other mechanical removal mechanisms) or other carbon removal methods may be used to remove some or all of these weakened carbon solids (i.e., carbon buildup).

[0069] In some embodiments, the regeneration product may be supplied / transported from the reactor to a regeneration exhaust component / equipment 1115. The regeneration exhaust component / equipment 1115 may include an atmospheric vent, combustion equipment, other processing / processing equipment, and / or other components / equipment associated with the regeneration exhaust. By way of example, the regeneration product may be burned in a dedicated and / or shared steam combustor, flare, or thermal oxidizer. It may also be vented directly to the atmosphere. In some embodiments, prior to venting to the atmosphere, the regeneration product may undergo treatment to reduce concentrations of trace contaminants such as oxygen, carbon monoxide, carbon dioxide, nitrogen, hydrocarbon species (e.g., methane, ethane, ethylene, etc.), and / or nitrogen oxides. Treatment devices may include dust filters, solid adsorbent beds, controlled combustion, catalyst beds, selective catalytic reduction (SCR), wet scrubbers with or without selective chemical adsorbents, electrostatic precipitators, etc. In some embodiments, the regeneration product, after any necessary processing, may be combined with other pyrolysis product streams in a single stack. The location of the exhaust stack, including its orientation and height, may be selected to conform to applicable standards, safety, industrial hygiene, environmental regulations, and / or good engineering practices. In some embodiments, the regenerated product / exhaust may be fed / transported from the reactor to a standard exhaust / downstream component 1118. In these examples, the system 1100 may or may not include a regenerated exhaust component 1115.

[0070] In some embodiments (not shown in FIG. 11 ), the pyrolysis / standard products and / or regeneration products may be recycled to system 1100, and the carbon oxides may be captured for sequestration, or the regeneration gas may be sent to another facility (e.g., if it is syngas from steam regeneration). For example, the pyrolysis products may be fed back to reactor 1110, fed to reactor 1110 and / or other components of system 1100, used to power components of system 1100, and / or used for other purposes for the pyrolysis products within the system. Similarly, in some examples, the regeneration products may be recycled to the pyrolysis process, pyrolysis reactor 1110, and / or pyrolysis system 1100 for further use.

[0071] In some embodiments, regeneration in reactor 1110 can result in an oxidizing atmosphere within reactor 1110 and / or system 1100 because the regeneration gas 1101 (i.e., regeneration oxidant 1101) contains oxygen. However, if any of the regeneration oxidant 1101 mixes with the system feed 1102 in reactor 1110, it can be explosive because the flammable gas (i.e., system feed 1102), which is above its autoignition temperature (due to the high temperature of pyrolysis), mixes with the oxidizing atmosphere (due to the regeneration oxidant 1101). Therefore, it is desirable to keep the regeneration oxidant 1101 and the system feed 1102 separate and prevent them from mixing within reactor 1110, especially at high temperatures. After regeneration, system 1100 can return to pyrolysis mode.

[0072] To help remove oxygen, oxygen-containing compounds, and / or flammable gases from the reactor 1110, the system 1100, in some examples, may include an inert gas stream 1103. For example, in some examples, after the system feed 1102 is deactivated, the system 1100 may feed the inert gas 1103 through the reactor 1110 and, in some examples, the downstream components 1118 to remove flammable gases (e.g., the system feed 1102, hydrogen gas, by-products, etc.) from the reactor 1110 and / or downstream equipment / components 1118. Similarly, in some examples, after the regenerative oxidant 1101 is deactivated (i.e., the regeneration mode is deactivated / stopped), the inert gas 1103 may be fed through the reactor 1110 to remove oxygen and / or oxygen-containing compounds (e.g., the regenerative oxidant 1101, regeneration products, etc.) from the reactor 1110. This helps prevent explosive mixtures within the reactor 1110 and / or the system 1100. Inert gas stream 1103 is not always necessary and may be avoided if the operation is designed to avoid flammable conditions. Thus, system 1100 may not include inert gas stream 1103 in some instances. For example, if steam is used as the regeneration oxidant 1101, inert gas stream 1103 may not be needed before initiating the regeneration process / mode (i.e., after system feed 1102 is quiesced). Instead, steam may be fed / injected directly into reactor 1110. The steam may react with residual system feed 1102 gases that have not yet been converted to hydrogen gas (e.g., through a high-temperature steam methane reformer process and / or another applicable steam reaction) and may also react with high-temperature carbon buildup accumulated within reactor 1110 (e.g., on tubes within reactor 1110). These reactions may primarily form carbon monoxide and hydrogen gas, along with some residual hydrocarbons and carbon dioxide, resulting in a synthesis gas stream, a potentially carbon dioxide-free product stream.

[0073] In some embodiments, for example, when inert gas stream 1103 is fed through reactor 1110 after system feed 1102 is paused, the inert gas outlet (also referred to herein as inert gas purge because it may include inert gas 1103 as well as any other gases purged from reactor 1110) may be transferred / fed to standard exhaust / downstream component 1118. In some embodiments, for example, when inert gas stream 1103 is fed through reactor 1110 after regenerative oxidant 1101 is paused, the inert gas purge may be transferred / fed to regenerative exhaust component 1115. In some embodiments, the inert gas purge may have a separate outlet component and / or endpoint.

[0074] To help control various flows through the system 1100 and the reactor 1110, the system 1100, in some examples, may include various valves 1104. In an illustrative example, the system 1100 may include a valve 1104a for controlling the flow of regenerative oxidant 1101 to the reactor 1110, a valve 1104b for controlling the flow of system feed 1102 to the reactor 1110, and / or a valve 1104c for controlling the flow of inert gas 1103 to the reactor 1110. For example, when the system 1100 is in pyrolysis mode, the valve 1104a may be closed (stopping / preventing the flow of regenerative oxidant 1101 to the reactor 1110), the valve 1104b may be opened (allowing the flow of system feed 1102 to the reactor 1110), and the valve 1104c may be closed (stopping / preventing the flow of inert gas 1103 to the reactor 1110). As another example, when system 1100 is in regeneration mode, valve 1104a may be opened (allowing the flow of regenerative oxidant 1101 to reactor 1110), valve 1104b may be closed (stopping / preventing the flow of system feed 1102 to reactor 1110), and valve 1104c may be closed (stopping / preventing the flow of inert gas 1103 to reactor 1110). As yet another example, when system 1100 is performing an inert gas purge, valve 1104a may be closed (stopping / preventing the flow of regenerative oxidant 1101 to reactor 1110), valve 1104b may be closed (stopping / preventing the flow of system feed 1102 to reactor 1110), and valve 1104c may be opened (allowing the flow of inert gas 1103 to reactor 1110). As yet another example, if system 1100 is undergoing mechanical carbon removal (e.g., using rotating elements and / or another mechanical removal method described herein), system 1100 may also be in pyrolysis mode, with valves 1104a-c in the same / similar positions described herein to allow system feed 1102 to flow through reactor 1110. As described herein, pyrolysis may not need to be paused / stopped for mechanical carbon removal.In some embodiments, by way of example, the system 1100 may include a valve 1104d for controlling flow from the reactor 1110 to the regenerative exhaust component 1115 and / or the standard exhaust / downstream component 1118.

[0075] 11 are intended to be exemplary, and the quantity and / or location / arrangement of these valves 1104 may vary. For example, in some examples, system 1100 may have a different number and / or location of valves 1104. In some examples, system 1100 may not include valves 1104, but may have different components for controlling flow through the reactor (including, by way of non-limiting example, separate feeds (e.g., inlets and / or outlets from reactor 1110) for each inlet (1101, 1102, 1103)) to help avoid crossover. In some examples, one or more of the valves 1104 may include multiple valves 1104 in that location (and / or similar locations).

[0076] In some embodiments, system 1100 and / or any of the other systems described herein (including, for example, systems 1300, 1400, etc.) may include a controller that may communicate with one or more components of system 1100.

[0077] FIG. 12 shows a schematic diagram of a reverse flow 1200 of a pyrolysis system (such as, for example, pyrolysis system 1100), according to one embodiment. In some embodiments, the regeneration mode / stage may be modified by flowing in the reverse direction of the standard reactor / system flow (shown in FIG. 11). The reverse flow 1200 may, in some instances, flow from right to left (reverse of the left-to-right flow shown in FIG. 11), feeding regenerative oxidant 1101 to reactor 1110 and feeding regenerated products / exhaust from reactor 1110 to regenerative exhaust component 1115. While FIG. 12 depicts regenerative exhaust component 1115, the regenerated products may, in some instances, instead be fed / transferred to standard exhaust / downstream component 1118.

[0078] Another alternative for modifying the regeneration stage is to use separate ports (e.g., to the regeneration exhaust component 1115 and / or other components) for the regenerated oxidant 1101 flow and / or regenerated product flow that are not shared with the standard flow ports for the standard pyrolysis streams (e.g., system feed 1102 inlet, product outlet, and / or the like). In some examples, the regenerated oxidant 1101 flow / path can change direction during the regeneration stage / mode (so that the oxidant 1101 flows, for example, first in a forward direction and then in a reverse direction), or can flow in a different direction in subsequent regeneration stages / modes after the cycle is repeated. The reverse flow direction can be the direction shown in FIG. 12 in some examples. The gas flow rate and regeneration duration can be varied in some cases to achieve an optimal regeneration profile. For example, sometimes the regeneration period can be long enough to remove all residual / hard-to-remove carbon buildup.

[0079] The duration of each regeneration stage may be determined in various ways. For example, a set time period or a set total volumetric and / or mass flow rate may be used before proceeding to the next stage (e.g., inert gas mode (for inert gas purging), pyrolysis mode, etc.). As another example, sensors in the exhaust stream from reactor 1100 (e.g., flowing to components 1115, 1118, and / or other components) may be used to determine when to proceed to the next stage / mode. As yet another example, sensors on and / or within reactor 1100 may be used to determine the volume, mass, location, hardness, and / or other characteristics of solid carbon accumulation, and the determined characteristics may be used to determine when to proceed to the next stage / mode. These sensors may include deflection sensors, torque sensors, load sensors, and / or other sensors. As yet another example, carbon dioxide and / or carbon monoxide emissions may be calculated from the regeneration stage, and emissions limits may be used to determine when to stop the regeneration (e.g., when to stop supplying regenerative oxidant 1101 to reactor 1110). As yet another example, a temperature sensor may be used to determine when regeneration begins, when to change the flow of regeneration gas to control the process, and / or when regeneration is complete. Any of these examples may be used alone and / or in combination to help determine the duration of each regeneration stage / mode of the reactor 1110. For example, a minimum period / duration of the regeneration mode may be determined and / or predetermined, and the duration may continue longer if sensor readings indicate it should.

[0080] In some embodiments, a thermal cycle may be used instead of or in addition to a regeneration cycle. In one such embodiment, based on a fixed period of time, some measurement of the flow of the pyrolysis product stream and / or some measurement on and / or within the reactor 1110 may trigger the initiation of heating or cooling of the reactor 1110. During this thermal cycle, the system feed 1102 may continue, an inert gas flow 1103 may be used (i.e., fed through the reactor 1110), and / or a regenerative oxidant 1101 may be used. In some examples, the system feed 1102 may continue to be fed to the reactor 1110, but the flow rate may be varied. In some examples, nothing may be fed to the reactor 1110 during the thermal cycle. In some embodiments, in addition to and / or instead of heating or cooling the reactor 1110 by increasing or decreasing the heat supplied to the reactor 1110, adjusting the streams supplied to the reactor 1110 (e.g., regenerative oxidant 1101, system feed 1102, and / or inert gas stream 1103) can also be used to generate a thermal cycle (heating or cooling depending on the specific characteristics of the provided gas streams). In some embodiments, the thermal cycle can be determined by a fixed duration, a fixed target temperature, sensor readings (as described above), and / or any combination thereof. In some examples, mechanical removal (such as a rotating element and / or another mechanical removal process) can be performed during and / or after the thermal cycle. In some embodiments, some and / or all of the carbon gasified to carbon monoxide and / or carbon dioxide during the regeneration process can be captured within the system 1100 to further reduce direct carbon dioxide emissions.

[0081] In some embodiments, a pyrolysis system (such as system 1100) may include additional and / or alternative components. FIGS. 13 and 14 illustrate some such exemplary systems. For example, FIG. 13 is a schematic diagram of a pyrolysis system 1300 with regeneration, according to one embodiment. System 1300 may be similar to system 1100, but may additionally and / or alternatively include an exhaust treatment component 1316. In this exemplary embodiment, exhaust treatment component 1316 may use a reverse reaction to help decarbonize the regeneration products. As described herein, one exemplary reverse reaction is the Boudouin reaction (2 CO → C + CO). Another exemplary reverse reaction is the Bosch reaction (CO + 2 H → C + 2 H0). Which reaction (e.g., the Boudouin reaction or the Bosch reaction) is utilized may depend, in some examples, on the concentration of carbon monoxide and / or carbon dioxide generated in reactor 1110 during regeneration.

[0082] The Boudouid reaction may be facilitated by flowing the carbon monoxide (CO)-rich exhaust through high surface area carbon produced by the pyrolysis reactor 1110 itself. Similarly, the Bosch reaction may reduce any carbon dioxide (CO) using hydrogen produced by the pyrolysis reactor 1110 itself. In some examples, the exhaust treatment component 1316 may utilize additional heat input or other types of catalysts to increase its effectiveness, and any solid carbon produced may be sent to exemplary downstream components 1118 and / or the carbon treatment stream of the pyrolysis reactor 1110.

[0083] In some examples, the exhaust gas obtained from exhaust treatment component 1316 may be recycled to the original source of regenerative oxidant 1101, such as recycled to reactor 1110 as regenerative oxidant 1101. In some examples, recycling may occur when carbon dioxide is used as regenerative oxidant 1101 because the mass balance is closed and, in principle, no additional carbon dioxide emissions are produced.

[0084] In some embodiments, as an alternative to and / or in addition to processing the regeneration product stream of the high temperature steam regeneration cycle (which may consist primarily of carbon monoxide (e.g., about 40%) and hydrogen gas (e.g., about 50%)), the resulting exhaust gas may be used to heat the pyrolysis reactor 1110 (e.g., by being transferred to a burner, combustion system, and / or another heat source), which may help reduce product gas recycle and / or may be supplied to potential syngas customers and / or other uses.

[0085] In some embodiments, the pyrolysis system includes a heat source, such as a combustion system. FIG. 14 shows one such pyrolysis system 1400 with regeneration capabilities, according to one embodiment. System 1400 can be similar to systems 1100 and / or 1300, but with the addition of a heat source (such as, in some examples, a combustion system 1408). If system 1400 includes combustion system 1408 (or another heat source), the source of regenerative oxidant 1101 can, in some examples, be provided within the combustion system 1408 used to heat and / or power reactor 1110, rather than a separate source. In the exemplary embodiment shown in FIG. 14, pyrolysis system 1400 can include a fuel component 1407, which can be a source of a hydrogen / hydrocarbon mixture that is combusted with air in combustion system 1408 to generate thermal energy provided to reactor 1110. Flue gas products, in some examples, can be output from combustion system 1408 and directed / transported completely and / or partially to the regenerative oxidant 1101 source. The flue gas transported from the combustion system 1408 to the regenerative oxidation device 1101 source may consist of a mixture of steam, oxygen, and / or carbon dioxide, depending on the fuel / fuel components 1407 and the characteristics of the combustion system 1408 .

[0086] In exemplary embodiments, pyrolysis systems 1100, 1300, and / or 1400 may perform pyrolysis (e.g., run in pyrolysis mode) for a given period of time, such as until a given thickness of carbon accumulates in reactor 1110. In some examples, mechanical carbon removal (such as rotating elements and / or another mechanical removal process) may be performed during pyrolysis and may continue through various other operations (including regeneration, inert gas purging, etc.). In some embodiments, as described herein, inert gas 1103 may be supplied to reactor 1110 to purge reactor 1110 and safely insert oxygen-containing chemicals into reactor 1110. Reactor 1110 may also, in some examples, begin to cool due to reactor 1110 being turned off and / or heat input to reactor 1110 being reduced. After the reactor 1110 has been properly purged with the inert gas 1103, in exemplary cases, air and / or another regenerative oxidant 1101 may be introduced into the reactor 1110 in a forward direction (e.g., at a high flow rate). This helps to blow (i.e., pump) soft particulates out of the reactor 1110 and further helps to wash / clean the reactor 1110, and may be done for a defined period of time. In some examples, the flow of air and / or regenerative oxidant 1101 may be reversed, possibly at a lower flow rate, to help better counteract carbon buildup in hard-to-reach portions of the reactor 1110 (e.g., regions further back in the reactor 1110), since the regenerative oxidant 1101 in the forward flow path may be depleted (e.g., already turned into regenerative products (i.e., carbon monoxide and / or carbon dioxide) before reaching the carbon at the rear of the reactor). In some examples, the system may flow either a set amount of regenerative oxidant 1101 and / or an amount based on the carbon thickness sensor reading, then stop the flow of regenerative oxidant 1101 and stop the regeneration mode. The system may, in some examples, perform another inert gas 1103 purge after the regeneration mode. In some embodiments, after regeneration (and, in some examples, during the inert gas 1103 purge), the reactor 1110 may continue to cool until it reaches a target temperature, and then the reactor 1110 may be heated back up to standard operating conditions.The change from cooling to heating can occur while the regenerated oxidant 1101 is flowing, while the inert gas 1103 is flowing, after regeneration is complete, and / or while the system feed 1102 is flowing (i.e., after pyrolysis has resumed). The system may resume pyrolysis in some instances once the reactor 1110 has been purged of inert gas and oxygen and is at a temperature high enough to drive the desired reaction.

[0087] In some embodiments, for example, if the reactor 1110 has such a large thermal mass that little change in temperature can be achieved, thermal cycles (e.g., reactor cooling and heating) may be skipped. In some embodiments, carbon dioxide and / or carbon monoxide emission limits may be used to determine when to stop regeneration, even if carbon thickness and / or other sensor readings are still unsatisfactory. In these cases, the reactor 1110 may eventually have to be shut down for a maintenance cycle and / or a more traditional regeneration cycle in which the carbon may be more completely oxidized and reset the reactor 1110. The regeneration duty cycle may also be modified. As a non-limiting example, the system may have multiple short pyrolysis / regeneration cycles followed by a longer, more complete regeneration cycle. In some embodiments, additional and / or alternative methods may be used to weaken carbon buildup in the reactor 1110. Some exemplary methods include applying vibration and / or mechanical stress to the carbon, finding a liquid to react with the carbon buildup, using steam as the regenerative oxidant 1101, etc.

[0088] As described herein, the various embodiments described above can be part of a system that includes a reactor, such as a pyrolysis reactor. For example, rotating elements (e.g., 105, 205, 305, 405, 505, 605, 805, and / or 905) can be used within the reactor to remove carbon buildup from the reactor and its reaction chamber (e.g., the pyrolysis chamber). Alternatively or additionally, the reactor can include regeneration functionality such that a regenerative oxidant can be supplied to the reactor to react with the carbon buildup to aid in the removal of carbon and / or to make it easier to remove via other means (e.g., the rotating elements and / or alternative carbon removal methods).

[0089] In some embodiments, a reactor, as referred to herein, is an arrangement of elements that constitute a device capable of supporting the steady-state conversion of an input stream of hydrocarbons (e.g., methane, propane, biogas, natural gas, etc.) to an output stream (e.g., product stream) of hydrogen gas, solid carbon, and a combination of unreacted hydrocarbons and other intermediates (e.g., intermediate polycyclic aromatic hydrocarbons (PAHs)). In some embodiments, the hydrogen gas, solid carbon, and a combination of unreacted hydrocarbons and other intermediate PAHs can exit the reactor in a single product stream. In some embodiments, one or more of the hydrogen gas, solid carbon, and / or a combination of unreacted hydrocarbons and other intermediate PAHs can exit the reactor in different product streams. In intended applications for the reactor and / or corresponding system, the hydrogen gas and solid carbon, once separated from the unreacted hydrocarbons and PAHs, are saleable product streams. In some embodiments, the conversion can be achieved by high-temperature pyrolysis; thus, in some examples, the reactor can be a pyrolysis reactor. As described herein, reactors (e.g., pyrolysis reactors) and / or corresponding systems (e.g., pyrolysis systems) can be efficient, modular, self-contained, and scalable systems suitable for long-term operation in a wide range of industrial and process applications.

[0090] FIG. 15 shows an exterior view of one such exemplary pyrolysis reactor 1500, according to one embodiment. In some embodiments, as described further herein, the reactor 1500 may include a pair of coaxially arranged but non-concentric tubes capable of sustained operation at high temperatures (e.g., 600° C.-2000° C.). The pyrolysis reaction may, in some cases, occur in the space between the two tubes. To generate a suitable temperature for the pyrolysis reaction to occur, the reactor 1500 may include a heat source 1505. In some embodiments, as described further herein, the heat source 1505 may be within the inner tube (of the pair of tubes). In the exemplary embodiment shown in FIG. 15, the heat source 1505 may be a burner 1505 that extends beyond the pair of tubes but extends (within the reactor) to a region within the inner tube (of the pair of tubes). In some embodiments, although FIG. 15 shows a burner as heat source 1505, heat source 1505 can be a different heat source, such as a resistive electric heater, a combustion component, and / or a device that generates an electromagnetic field to deliver energy to the reactants (e.g., an induction source or a microwave source), and / or another type of heat source.

[0091] In some embodiments, reactor 1500 may include a feed manifold 1544 for receiving source hydrocarbons (e.g., system feed 1102, etc.), regenerative oxidant (e.g., regenerative oxidant 1101, etc.), and / or inert gas (e.g., inert gas 1103, etc.) into an inlet end 1544 of a crescent-shaped volume formed between two coaxial but non-concentric tubes (e.g., volume 1714 ( FIG. 17 ) described further herein). In some embodiments, feed manifold 1544 may include a first inlet 1503 a and a second inlet 1503 b, either or both of which may be used to receive hydrocarbons, regenerative oxidant 1101, or other fluids for purposes of cooling, heating, dilution, concentration, or catalysis. Other inlets may also be provided.

[0092] 15, reactor 1500 may include a collector plenum 1532a (also referred to as collector manifold 1532a) at the discharge end 1542 (also referred to as outlet end 1542) of the multi-tube reactor 1500 system positioned to receive the product stream (i.e., effluent hydrogen gas, solid carbon, and PAHs) from the pyrolysis process (occurring within the crescent-shaped volume formed between two coaxial, non-concentric tubes, such as crescent-shaped volume 1714). In some embodiments, the collector plenum may include an exhaust port through which at least hydrogen gas (and / or other components of the product stream) may be removed from reactor 1500. In some embodiments, manifold 1506 may be used to collect flue gas from heat source 1505, if present, and / or regeneration products from any regeneration cycle.

[0093] 19A , in some embodiments, an array of reactors 1900 can include an enclosure 1950 for housing the reactors 1500 and other components. In some examples, the enclosure 1950 can include a pair of support elements and / or plates 1532 a, b at each end of a central housing 1531. For example, a first end of the central housing 1531 (e.g., near the inlet end 1542 of the reactors 1500) can include a first support element 1532 a (also referred to as support plate 1532 a). A second end of the central housing 1531 (e.g., near the inlet end 1544 of the reactors 1500) can include a second support element 1532 b (also referred to as support plate 1532 b). In some embodiments, one or more of the support elements 1532 can include multiple support elements / plates 1532. For example, FIG. 15 shows a support element 1532 a having multiple support plates 1532 a. As another example not shown, the support element 1532b can include multiple support plates 1532b and / or the support element 1532a can have a single support plate 1532a. In some embodiments, the combination of the support element 1532 and the central housing 1950 forms an enclosed volume that can be filled with suitable insulation to mitigate heat loss from the pyrolysis reactor module mounted between the two end support elements 1532.

[0094] FIG. 16 shows a simplified cross-section (e.g., an XY plane cross-section) of a reactor 1500 having a two-tube arrangement as described herein, and FIG. 17 shows a simplified schematic diagram of another cross-section (e.g., a YZ plane cross-section) of the two-tube arrangement. For example, as shown in FIG. 16, the reactor 1500 can include at least two tubes, namely, tube 1610 and tube 1620. In some examples, tube 1610 may be referred to herein as an inner tube, and tube 1620 may be referred to herein as an outer tube. As described herein, tubes 1610 and 1620 can be a pair of coaxially arranged, non-concentric tubes 1610, 1620. As a result of the coaxial, non-concentric arrangement of tubes 1610, 1620, a crescent-shaped passage 1714 can be formed between tubes 1610, 1620. This passage can also be referred to as a crescent-shaped volume 1714, and passage 1714 can constitute a volume in which the pyrolysis process is stabilized. In some embodiments, tube 1610 and / or tube 1620 can be rotating elements (such as rotating elements 105, 205, 305, 405, 505, 605, 805, and / or 905). For example, tube 1610 and tube 1620 can be supported (e.g., within reactor 1500) so that they can rotate about their longitudinal axes. In some examples, the rotation of tubes 1610, 1620 can be in opposite and / or counter-rotating directions. The purpose of this rotation can be to generate opposing relative motion of tubes 1610, 1620, particularly at the position where tubes 1610, 1620 are closest to each other (as shown at position 1716 in FIG. 17 ). In some embodiments, tubes 1610 and 1620 can be the same as and / or similar to tubes 905 and 910 ( FIGS. 9A and 9B ).

[0095] In some embodiments, as described herein, the heat source 1805 can be located at the center of the inner tube 1610. This is shown in FIG. 18. In some embodiments, the heat source 1805 can be a resistive electric heater, a combustion component, a device that generates an electromagnetic field to deliver energy to the reactants (e.g., an induction or microwave source), a burner, and / or another heat source 1805. In some embodiments, at least a portion of the heat source 1805 can extend 1505 beyond the inner tube 1610, as shown in FIG.

[0096] 16 and 17, during pyrolysis operation (also referred to herein as pyrolysis mode), the tubes 1610, 1620 can be heated internally and / or externally while both tubes 1610, 1620 are driven to counter-rotate. In some examples, only one of the tubes 1610, 1620 may rotate. The heat source (heating the tubes 1610, 1620) can drive the temperature of the volume 1714 as high as 2000°C in some examples. In some examples, the heat source can be a resistive electric heater, a combustion component, a device that generates an electromagnetic field to deliver energy to the reactants (e.g., an induction source or a microwave source), a burner, and / or another heat source. While volume 1714 is being heated, a system feed (e.g., hydrocarbons) may be introduced at the inlet end 1504 of the reactor 1500 and may flow along a length (e.g., length 1617) of the crescent-shaped cross-sectional passage (e.g., volume 1714) formed between the two tubes 1610, 1620. As the system feed flows along this passage, it may receive heat from the tube 1610. As described herein, in some examples, the heat source may be at the center of the inner tube 1610. As the system feed approaches a midpoint (e.g., midpoint 1645) along the axial length of the space (e.g., volume 1714) between the two tubes 1610, 1620, the system feed may achieve its maximum temperature, the pyrolysis process (e.g., pyrolysis reaction) may proceed at its maximum rate, and substantially all of the system feed (e.g., hydrocarbons) may be converted to hydrogen gas, solid carbon, and / or PAHs.

[0097] In some embodiments, some of the carbon that is formed may flow as part of the product stream (e.g., with the hydrogen gas) and / or may precipitate on the surfaces of the tubes 1610, 1620 as a soft powder. The remainder of the carbon may accumulate, in some instances, by chemical vapor deposition (CVD) on the hot walls of the rotating inner and outer tubes 1610, 1620 (also referred to herein as rotating elements). The high surface temperatures of the walls of the tubes 1610, 1620 may cause a very hard, dense carbon layer to grow on these surfaces. This hard, dense carbon layer is referred to herein as carbon buildup. If the carbon buildup is not removed from the surfaces of the tubes 1610, 1620, it may gradually build up and eventually fill and block the entire space between the tubes (possibly including the crescent space 1714 and / or the smaller space at location 1716).

[0098] However, in a non-concentric arrangement of the two tubes 1610, 1620, the combination of the counter-rotation of the tubes 1610, 1620 and the narrow gap 1716 formed by the minimum spacing of the crescent-shaped cross-sections 1714 between the tubes 1610, 1620 creates a zone (which may be referred to herein as zone 1716) where hard carbon (i.e., carbon buildup) on the surface of the outer tube 1620 rubs against and / or grinds down the hard carbon on the surface of the inner tube 1610. In some examples, by appropriately selecting the diameter, speed, and carbon deposition rate of the tubes 1610, 1620, an equilibrium condition can be established where carbon buildup on the surfaces of the tubes 1610, 1620 is grinded down and removed (e.g., by the rotating tubes 1610, 1620 (also referred to herein as rotating elements)) at a rate equal to the rate at which it is formed. This condition is shown schematically in FIG. 2. As the carbon buildup is removed through this grinding process, it is reduced to a powder-like form that falls to a nadir 1718 on the crescent-shaped cross-sectional area 1714 between tubes 1610, 1620. The carbon powder that falls to nadir 1718 can then roll along this zone / area, driven by the rotation of tubes 1610, 1620, fluidization by the gas flow, or both, and can be conducted axially along the length (e.g., length 1617) of the gap / opening between tubes 1610, 1620, along with the hydrogen gas and PAHs. In other words, after being ground into a powder, the carbon accumulates powder, falls to nadir 1718, then flows through reactor 1500, and can then be carried out of reactor 1500 with the product stream (including hydrogen gas and PAHs) exiting reactor 1500. Finally, the product stream (including hydrogen gas, PAHs, and any unreacted hydrocarbons) along with the carbon accumulation powder (also referred to herein as solid carbon powder) exits the space between the tubes 1610, 1620 at the exit end 1544 and enters the collector plenum 1532a. Once in the collector plenum 1532a, the carbon powder may fall to the bottom of the collector 1504 where it may be removed from the reactor 1500, and the hydrogen gas may be removed from the reactor 1500 through the carbon collector plenum 1532a.

[0099] In some embodiments, the rubbing and / or grinding (of the rotating tubes 1610, 1620 and / or other rotating elements described herein) may occur for an extended period of time in an inert environment (i.e., the rotating tubes 1610, 1620 and / or other rotating elements described herein may have an extended period of grinding / rubbing in an inert environment). This increases the friction coefficient and / or carbon removal. Rubbing and / or grinding may refer to carbon rubbing due to the rotation of one or more tubes and / or rotating elements. In some embodiments, the inert environment is a non-reactive environment within the reactor 1500 and / or passageway 1714. As an exemplary embodiment, the inert environment may be established by an inert gas supply / flow (e.g., inert gas flow 1103, etc.).

[0100] As described herein, the wall temperatures (e.g., at least of the walls of tubes 1610 and 1620) required to adequately heat the system feed (e.g., hydrocarbons) to drive rapid pyrolysis (e.g., temperatures of 600°C to 2000°C) result in the accumulation of a dense, hard carbon coating or layer (referred to herein as carbon buildup) on the walls defining the pyrolysis zone (i.e., the outer wall of tube 1610 and the inner wall of tube 1620). The outer wall of tube 1610 and the inner wall of tube 1620 may, in some examples, be the same as and / or similar to outer surface 107 and second surface 110, respectively (FIG. 1), outer surface 507 and inner surface 510, respectively (FIG. 5A), outer surface 907 and inner surface 908, respectively (FIGS. 9A and 9B), etc. The accumulated hard carbon, along with powdered gas-borne carbon flowing with the product stream and / or hydrogen gas product, constitutes the total carbon production of reactor 1500 and / or the system. Although the gas-borne carbon powder can easily flow out of the reactor, an additional mechanism is required to continuously remove the hard carbon buildup from the walls of the reactor tubes 1610, 1620 and convert it into a form that can be easily and continuously discharged from the reactor 1500.

[0101] In some embodiments, the additional mechanism may be a rotating element / tube described herein (such as rotating elements 105, 205, 305, 405, 505, 605, 805, and / or 905 and / or rotating tubes 1610, 1620). Given the density and hardness of the hard carbon (i.e., carbon buildup) layer on the walls of the reactor tubes 1610, 1620, the reactor 1500 may remove the carbon buildup by rubbing one hard carbon coated surface against another surface (i.e., rubbing hard carbon (i.e., carbon buildup) against hard carbon (i.e., carbon buildup)). If the rates of buildup and removal of carbon buildup layers on the respective surfaces / walls of tubes 1610, 1620 can be approximately balanced, the reactor 1500 system and rotating element / tube configuration can provide an equilibrium and / or near-equilibrium state (e.g., a state in which the carbon buildup coating on both surfaces (i.e., the inner wall of tube 1620 and the outer wall of tube 1610) is continuously reduced to a powder-like form that can be easily removed from the reactor 1500 and supports continuous and / or near-continuous operation).

[0102] At an equilibrium state where the removal rate and deposition rate of carbon buildup are balanced, the scraping and / or grinding process (of the rotating tubes 1610, 1620) may require a normal or contact force between two surfaces (i.e., the inner wall of tube 1620 and the outer wall of tube 1610). This force may be generated by a bending deflection of the inner tube 1610 relative to the outer tube 1620. The bending load may be reacted by a bearing system, as described further herein.

[0103] In some embodiments, the bearing / bearing system support structure may be equipped with strain gauges or other suitable deflectometers to provide real-time feedback on the normal forces generated by the buildup of hard carbon on the tube walls (i.e., carbon buildup) and the spalling of the two hard carbon coated surfaces (i.e., the inner wall of tube 1620 and the outer wall of tube 1610). If the carbon buildup accumulates at a rate greater than it is removed, then the bending deflection of the tubes 1610, 1620 may exceed the strength of the tubes 1610, 1620, and one or both of the tubes 1610, 1620 may fail.

[0104] To help avoid excessive hard carbon buildup (i.e., excessive carbon accumulation), regeneration may be used in some examples. As described herein, regeneration may include flowing a regenerative oxidant through passageway 1714 (also referred to herein as the reaction chamber 1714 and / or the pyrolysis chamber) to react with the carbon buildup and change its structural properties. This may help remove the carbon buildup and / or make it easier to remove the carbon using the rotating tubes 1610, 1620. In some embodiments, to avoid excessive hard carbon accumulation, the reactor 1500 may switch from pyrolysis mode to regeneration mode when the normal force acting between the two counter-rotating tubes 1610, 1620 reaches a threshold level. In other words, when the normal force acting between the two counter-rotating tubes 1610, 1620 reaches a threshold level, the supply of the system feed may be terminated, and instead, a controlled supply of regenerative oxidant may be supplied to the reactor 1500. As the regenerative oxidant flows through the passage 1714 between the tubes 1610, 1620, the presence of oxygen can cause oxidation of the hard carbon buildup. This can result in at least a portion of the carbon buildup being consumed and removed via oxidation, and / or the carbon structural properties can change, making the carbon buildup easier to remove by the rotating tubes 1610, 1620. In some embodiments, real-time tube bending load measurement (for tubes 1610 and / or 1620) can be provided by strain gauges or deflectometers and can provide a control variable to limit the use of the regeneration process (also referred to herein as regeneration mode) as needed.

[0105] As described herein, regeneration may result in a decrease in system efficiency and an increase in carbon dioxide emissions due to the cessation of pyrolysis (to avoid explosive mixtures) and the production of regeneration products (which, as described herein, may include carbon dioxide). Nevertheless, periodic intermittent regeneration is an effective option for enabling long-term reliable system and reactor (e.g., reactor 1500) operation. Furthermore, as described herein, regeneration may be performed for a relatively short period of time such that the carbon buildup is not completely consumed / removed from oxidation, but instead the structural properties of the carbon buildup are altered to make it easier to remove the carbon. This may reduce the amount of decrease in system efficiency and the increase in carbon dioxide emissions due to regeneration, as regeneration is performed for a shorter period of time.

[0106] 19, an array of reactors 1900 is shown according to one embodiment. In some embodiments, as described herein, gas-borne carbon powder, and even carbon powder produced by a carbon-on-carbon grinding process (from the rotating tubes 1610, 1620 in each reactor 1500), may be convected along the length of the crescent-shaped ring / passage 1714 (such as length 1617 in FIG. 16 ) between the tubes 1610, 1620 by the incoming system feed (e.g., hydrocarbons) and the outgoing hydrogen gas. However, larger pieces of carbon that may be formed in the carbon-carbon grinding process may be large enough that they cannot (or are much more difficult to) convect out of the reactor 1500 by momentum exchange with the gas flow alone. Thus, in some examples, the arrangement of coaxial non-concentric rotating tubes 1610, 1620 (and / or the entire reactor 1500 arrangement) may be tilted 1918 at an appropriate angle relative to the horizontal to provide additional driving force to carry larger pieces of carbon buildup out of the reactor 1500. This creates an axially acting gravitational component that provides additional force to drive any larger pieces of carbon buildup out of the reactor tubes / chambers and into the collector plenum 1504.

[0107] In some embodiments, as shown in FIG. 19 , a system may include an array 1900 of reactors 1500 (also referred to herein as reactor modules 1500 and / or reactor assemblies 1500) mounted within a containment vessel 1950. This may increase hydrogen production and, in some instances, reduce system inefficiencies due to regeneration. For example, one or more reactors 1500 may be in a pyrolysis mode (i.e., undergoing pyrolysis and producing a product stream including hydrogen gas), while another one or more reactors 1500 are in a regeneration mode (i.e., undergoing regeneration). This may help prevent excessive carbon buildup while ensuring that at least one reactor 1500 is always producing hydrogen gas. In some embodiments, as shown in FIG. 19 , the array 1900 of reactors 1500, as well as the containment vessel 1950, may be tilted 1918 relative to the horizontal.

[0108] As described herein, high-temperature pyrolysis can reach very high temperatures (e.g., up to 2000°C). These high pyrolysis temperatures necessitate the use of materials capable of operating at very high temperatures. Therefore, in some embodiments, the inner and outer reactor module tubes (tubes 1610 and 1620, respectively) can be fabricated from materials such as engineered ceramics. Examples of engineered ceramics include alumina (Al2O3), mullite (Al2O3 + SiO2), silicon carbide (SiC), silicon nitride (Si3N4), ceramic matrix composites (CMCs), and / or other engineered ceramics. While these exemplary materials have the thermal capabilities necessary to support the pyrolysis process, the need to attach bearings, drive gears, and / or other mechanical features to the tubes 1610, 1620 necessitates a transition from the ceramic tubes 1610, 1620 to more conventional high-temperature metal alloys on each end of both the inner tube 1610 and the outer tube 1620. Attaching these metal ends and / or adapters to each end of the ceramic tubes 1610, 1620 is made difficult by the difference in coefficient of thermal expansion (CTE) between the ceramic material of the tubes 1610, 1620 and the appropriate high temperature alloy material of the metal ends / adapters.

[0109] Figures 20A and 20B show a metal end adapter assembly 2055 that can be attached to both ends of each tube 1610, 1620. Figure 20B shows a cross section through the metal end adapter assembly 2055 on one end of the tube 1620, highlighting the ceramic tube wall, the metal adapter, and an intermediate element between the adapter 2055 and the ceramic tube 1620. However, as described herein, the metal end adapter assembly 2055 can also be on the second end of the tube 1620 or on both ends of the tube 1610. Figure 20A shows the intermediate metal element 2058 on the end of the ceramic tube; the metal adapter is not shown for clarity.

[0110] In some embodiments, the metal end adapter assembly 2055 can be a two-component system of metal alloy parts that work together to accommodate the CTE mismatch between the ceramic reactor tubes (1610 and / or 1620) and a metal end adapter (e.g., metal end adapter assembly 2055), which can accommodate the attachment and integration of mechanical elements necessary to support and drive the reactor tubes 1610, 1620. The metal end adapter assembly 2055 can include an outer metal adapter sleeve 2056 made of a suitable alloy that can operate at high temperatures, in some examples, up to 300°C-800°C, and retain adequate strength (the temperatures in this region of the reactor 1500 can be high, but not as high as the pyrolysis region and pyrolysis operating temperatures). The sleeve 2056 can be concentrically disposed around the tube (in this illustrative example, tube 1620) with an annular gap between the outer wall of the tube 1620 and the inner wall of the metal adapter sleeve 2056.

[0111] A second metal alloy element 2058 (also referred to herein as an intermediate annular element 2058) may be disposed in the annular gap between the tube 1620 and the outer metal adapter sleeve 2056. The intermediate annular element 2058 may be designed to utilize its own thermal growth along the longitudinal axis of the tube. For example, as the intermediate annular element 2058 grows axially due to high temperature operation, the beveled features 2059 on each axial end of the metal end adapter assembly 2055 may engage corresponding beveled features formed on the outer walls of the tubes 1610, 1620. As axial thermal expansion of the intermediate annular element 2058 increasingly drives the intermediate annular element into contact with corresponding features on the tube (e.g., 1610 and / or 1620), the two ramped features (including 2059) cooperate to drive the intermediate annular element 2058 radially outward to continuously fill the growing gap between the tube (e.g., 1610 and / or 1620) and the outer metal adapter sleeve 2056. This can maintain a tight fit capable of transferring necessary loads from the tube (e.g., 1610 and / or 1620) into the metal end adapter assembly 2055.

[0112] In some embodiments, the intermediate annular element 2058 is formed with a circumferentially interrupted configuration, which allows the intermediate annular element 2058 to grow longitudinally and / or axially in response to increased operating temperatures, as described herein (e.g., to drive a desired interaction between the ramped features 2059 on the metal end adapter assembly 2055 and the corresponding ramped features on the walls of the tubes (1610 and / or 1620)). This interrupted configuration allows the intermediate annular element 2058 to avoid circumferential growth that would occur if the element 2058 were continuous in the circumferential dimension. In some embodiments, the metal end adapter assembly 2055 can be removed from one tube and replaceably installed on another tube in the event of tube failure.

[0113] FIG. 21 shows the location of reaction loads and associated bearing structures within reactor 1500, according to one embodiment. As described herein, reactor 1500 can include one or more rotating elements (e.g., rotating tubes 1610 and 1620). Internal load-supporting features of reactor 1500 can have an arrangement that supports counter-rotating reactor tubes 1610 and 1620. For example, to avoid difficult end-to-end alignment requirements for reactor 1500, the reactor assembly can be fully modular and structurally self-supporting. FIG. 21 shows the carbon outlet end of reactor 1500 with reaction loads F1 (2101), F2 (2102), and F3 (2103) acting at three radial bearing locations. In some embodiments, the opposite end of reactor 1500 can be a mirror image of this bearing arrangement. During operation, carbon buildup and the associated self-rubbing action between the reactor tubes 1610, 1620 (i.e., rotation / movement of the tubes 1610, 1620) creates a normal force (F c ) 2104. This normal force 2104 can create an internal expansion effect that can apply a bending load to the two reactor tubes 1610, 1620.

[0114] FIG. 22 shows a free body diagram of a counter-rotating, two-tube reactor 2200, according to one embodiment. In some embodiments, the reactor 2200 can be the same as and / or similar to the reactor 1500. As shown in FIG. 22, the reactor 2200 can include an inner tube 1610 and an outer tube 1620. Furthermore, as described herein and shown in FIG. 22, hard carbon 2208 can accumulate between the outer tube 1620 and the inner tube 1610 (i.e., carbon buildup 2208). In some embodiments, the inner tube 1610 assembly can extend beyond the end of the outer tube 1620 (indicated by arrow 2262). This can be necessitated in some instances by the concentration of high temperatures toward the center span of the reactor tubes 1610, 1620, as well as the physical space requirements to accommodate both the inflow of system feed (e.g., hydrocarbons) (at the inflow end 2242) and the outflow of carbon and hydrogen (at the outflow end 2244). This arrangement may result in the bearings (e.g., bearing support structure 2270) required to support the two counter-rotating reactor tubes 1610, 1620 being longitudinally or axially offset (e.g., 2271) from one another. This offset (2271) between the bearings 2270 can result in moments being applied to the bearing support structure 2270, which typically requires some form of external rigid support for the bearing support structure 2270, for example, rigidly fastening both bearing cartridges to a base element or alternatively to one another. This independent load path is a complex requirement for the design of an integrated system, coupling the reactor 1500 to some additional elements and / or assemblies.

[0115] In some embodiments, an alternative approach relying on statically indeterminate bearing arrangements may be employed, which complicates load analysis but eliminates the need for any external load paths between the bearing support structures 2270 at each end of the reactor 2200 (also referred to as reactor modules 2200). Eliminating the need for external load paths or connections to the bearing support structures 2270 may be a significant simplification of the design. Eliminating the need for external load paths / connections may mean that the bearing support structures 2270 on each end of the reactor 2200 need only be simple, non-rigid supports that can simply support the reactor 2200 against gravity loads. In the case of a system having an array of reactors / reactor modules 2200 mounted in a housing (in some examples, the same and / or similar to array 1900), this alternative approach may eliminate the need to maintain any careful alignment of support features at one end of the housing to features at the other end of the containment housing.

[0116] 22, reactor 2200 can include at least reaction force (R1) 2213, reaction load (F1) 2101, reaction force (R2) 2215, and reaction force 2217. In some embodiments, by way of example, reaction force 2217 can be between about 1,000 and 10,000 pounds.

[0117] In some reactor systems, support for inner tube 1610 and outer tube 1620 may each be achieved by rolling element bearings (including, but not limited to, some forms of ball, needle, and / or cylindrical element bearings). However, these types of bearings may require lubrication, which has operating temperature limitations and physical form factors that would make their integration into a pyrolysis reactor (e.g., reactor 1500, reactor 2200) difficult. Furthermore, the use of any type of conventional rolling element bearing requires some form of cooling. While this cooling may be achieved by active recirculation and cooling of the lubricant, the seals, lines, external coolers, and / or other auxiliary systems required to perform this function have an undesirable impact on the size and cost of the modular reactor assembly.

[0118] Therefore, to avoid these adverse effects on system cost and size, reactor 2200 (and, in some examples, reactor 1500) may include custom low-profile hybrid bearings 2270 (e.g., ceramic rolling elements and high-temperature metal races) to support both the inner and outer reactor tubes (tubes 1610 and 1620, respectively). It is recognized that hybrid and all-ceramic bearings may operate without conventional hydrodynamic lubrication, either completely unlubricated or using only dry film lubricants. Furthermore, hybrid and all-ceramic bearings are well-proven in high-temperature applications (desirable for high-temperature pyrolysis). In some embodiments, clean, cold buffered inert gas may be circulated through bearing 2270 to maintain the bearing at the desired operating temperature while simultaneously creating positive pressure within the bearing galleries to prevent the ingress of any product carbon powder, gases, and / or other contaminants.

[0119] In some embodiments, the various components described herein may operate at higher process pressures (e.g., up to 100 bar), with different cooling media (e.g., oil and / or other cooling media using process flow as the coolant), at lower temperatures with superalloy instead of ceramic heat exchange tubes, with reciprocating and / or helical motion of the tubes, and / or other additional or alternative operating variations.

[0120] Figure 23 shows an exemplary method for removing carbon buildup from a reactor, according to one embodiment. In some embodiments, method 2300 may be performed by systems and / or components such as those described herein in connection with Figures 1-22. In some embodiments, various systems described herein may include one or more controllers, and method 2300 may be performed by a controller of the system. Exemplary operations of method 2300 are described below, although method 2300 may include any of the removal methods and / or techniques described herein.

[0121] Method 2300 may include an operation 2310 of providing a pyrolysis system. In some embodiments, the pyrolysis system may include a pyrolysis reactor, a regenerative oxidant feed, and a mechanical removal mechanism. As described herein, the pyrolysis reactor may include a pyrolysis chamber configured to generate a product stream from a system feed, where the system feed includes a hydrocarbon reactant and the product stream includes hydrogen gas and solid carbon. In some embodiments, as described herein, a regenerative oxidant feed may be provided to the reactor with the intent of modifying the structural characteristics of the carbon buildup without completely removing it. This may help make carbon removal easier through mechanical means (i.e., the mechanical removal mechanism), while also preventing excessive carbon dioxide emissions due to a complete regeneration reaction and duration (since the regeneration mode may not be performed for the full duration). In some embodiments, the pyrolysis reactor may be a reactor, such as reactor 1500 and / or 2200, and may include a pair of coaxially arranged, but non-concentric, tubes (e.g., tubes 1610 and 1620). These tubes may, in some examples, be counter-rotating tubes. In some embodiments, the rotating tubes (e.g., 1610 and 1620) are the mechanical removal mechanism. In some embodiments, the pyrolysis system may include additional and / or alternative components, such as those described herein.

[0122] Method 2300 may include an operation 2315 for controlling the flow of the system feed through the pyrolysis reactor. As described herein, the system feed and regenerative oxidant should be avoided from being fed to the reactor simultaneously in most cases. Thus, in some examples, controlling the flow of the system feed may include feeding the system feed through the pyrolysis reactor when the pyrolysis system is in pyrolysis mode and stopping the flow of the system feed through the pyrolysis reactor when the pyrolysis system is in regeneration mode. In some examples, operation 2315 may include additional and / or alternative steps of controlling the flow of the system feed.

[0123] Method 2300 may include an operation 2320 for controlling the flow of the regenerative oxidant feed through the pyrolysis reactor. In some embodiments, controlling the flow of the regenerative oxidant feed may include stopping the flow of the regenerative oxidant feed through the pyrolysis reactor when the pyrolysis system is in pyrolysis mode and feeding the regenerative oxidant feed through the pyrolysis reactor when the pyrolysis system is in regeneration mode. This may help prevent explosive mixtures. In some examples, operation 2315 may include additional and / or alternative steps of controlling the flow of system feeds.

[0124] Method 2300 may, in optional embodiments, include operation 2325 for controlling an inert gas flow through the pyrolysis reactor. As described herein, an inert gas flow / purge may be used to purge oxygen-containing and / or flammable chemicals from the reactor to avoid explosive mixtures. However, as described herein, an inert gas purge may not always be necessary. Thus, in some examples, the system may not always include an inert gas flow and / or may not always supply inert gas through the reactor between stages (e.g., between pyrolysis mode and regeneration mode, or vice versa). If the system is purging the reactor, operation 2325 may include flowing an inert gas flow through the pyrolysis reactor between pyrolysis mode and regeneration mode and / or between regeneration mode and pyrolysis mode, where the inert gas flow purges gas from the pyrolysis reactor.

[0125] Method 2300 may include operation 2330 for controlling movement of a mechanical removal mechanism. As described herein, in some examples, regeneration may not be utilized to completely remove carbon buildup from the reactor, but instead to weaken the carbon so that it can be more effectively removed through mechanical means. In some embodiments, these mechanical means may include a mechanical removal mechanism, where movement of the mechanism removes at least a portion of the carbon buildup. Thus, in some embodiments, operation 2330 may include moving the mechanical removal mechanism when the pyrolysis system is in pyrolysis mode and when the pyrolysis system is in regeneration mode, since the mechanical removal mechanism may be implemented during pyrolysis and / or regeneration. In some embodiments, the mechanical removal mechanism may be a rotating element and / or tube described herein. In some embodiments, controlling the movement of the mechanical removal mechanism may include rotating one or more rotating elements / tubes. For example, if the system / reactor includes two rotating tubes (such as tubes 1610 and 1620), controlling the movement of the mechanical removal mechanism may include rotating the tubes in opposite and / or counter-rotating directions. In some examples, operation 2330 may include additional and / or alternative steps of controlling the flow of system feeds.

[0126] Advantages of embodiments disclosed herein may include effectively removing carbon buildup from a pyrolysis reactor without complete shutdown and / or decomposition and without interrupting hydrogen production using mechanical removal methods such as rotating elements; weakening the carbon buildup (by regeneration and / or thermal cycling) to increase the effectiveness of removal and prevent damage to the system, making it easier and more effective to remove by other removal methods; reducing and / or eliminating carbon dioxide emissions resulting from regeneration (through shorter duration of regeneration, downstream processing of regeneration products, etc.);

[0127] To facilitate an understanding of the subject matter described herein, many aspects are described in terms of sequences of actions. The description of any sequence of actions herein is not intended to imply that the particular order described must be followed to perform the sequence of actions. All methods described herein may be performed in any suitable order unless otherwise indicated herein or clearly contradicted by context.

[0128] The use of the terms "a," "an," and "the" and similar references in the context of describing the subject matter should be construed to encompass both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term "at least one" followed by a list of one or more items (e.g., "at least one of A and B") should be construed to mean one item selected from the listed items (A or B), or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. Furthermore, the scope of protection sought is defined by this application, and the foregoing description is illustrative only, not limiting. The use of any and all examples, or the use of exemplary language (e.g., "such as") provided herein is intended merely to better illustrate the subject matter and does not impose limitations on the scope of the subject matter. In both any claim and the written description, the use of the term "based on" and other similar phrases indicating a condition for producing a result is not intended to exclude any other conditions for producing that result. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of any claimed invention.

[0129] While specific examples are provided above, it is understood that the present invention may be applied with a wide variety of inputs, thresholds, ranges, and other factors, depending on the application. For example, while the time frames and ranges provided above are exemplary, one skilled in the art will understand that these time frames and ranges may change or even be dynamic and variable, depending on the implementation.

[0130] As those skilled in the art will appreciate, several modifications can be made in the disclosed embodiments without departing from the scope of the present disclosure. It should be noted that although features and elements are described in particular combinations, each feature or element can be used alone without other features and elements, or in various combinations with or without other features and elements. The provided methods or flowcharts can be implemented in a computer program, software, or firmware tangibly embodied in a computer-readable storage medium for execution by a general-purpose computer or processor.

[0131] Thus, embodiments of a pyrolysis system with effective carbon buildup removal are disclosed. Although the invention has been described in considerable detail with reference to certain disclosed embodiments, the disclosed embodiments are presented for purposes of illustration and not limitation, and other embodiments of the invention are possible. Those skilled in the art will appreciate that various changes, adaptations, and modifications can be made without departing from the spirit of the invention.

Claims

1. 1. A pyrolysis reactor configured to produce a product stream from a system feed, the system feed comprising a hydrocarbon reactant, the product stream comprising hydrogen gas and solid carbon, the reactor comprising: a rotating element including a first surface; a second surface spaced apart from the first surface by no more than a predetermined distance, wherein in operation: the first surface and / or the second surface are positioned to receive the solid carbon, resulting in carbon buildup on the first surface and / or the second surface; A pyrolysis reactor, wherein the first surface and / or the second surface are configured to remove at least a portion of the carbon buildup as the rotating element rotates.

2. 10. The reactor of claim 1, wherein the rotating element comprises a first rotating element and the pyrolysis reactor further comprises a second rotating element comprising the second surface.

3. 3. The reactor of claim 2, wherein during operation, the carbon buildup is received at the first surface and the second surface.

4. 3. The reactor of claim 2, wherein the first rotating element and the second rotating element are configured to rotate in the same direction.

5. 3. The reactor of claim 2, wherein the first rotating element and / or the second rotating element are configured to stop rotation and / or reverse direction of rotation based on at least one of sensor feedback and a time interval.

6. 3. The reactor of claim 2, wherein the first rotating element and the second rotating element have different cross-sectional dimensions.

7. 3. The reactor of claim 2, wherein the first rotating element and the second rotating element have different shapes.

8. 3. The reactor of claim 2, wherein rotation of the first rotating element and the second rotating element causes the carbon buildup to be removed from the first surface and the second surface, respectively.

9. 3. The reactor of claim 2, wherein the first rotating element and the second rotating element are helical rotating elements.

10. 2. The reactor of claim 1, wherein the predetermined distance is between 0.5 millimeters and 500 millimeters.

11. The reactor of claim 1 , wherein the predetermined distance is movable.

12. 10. The reactor of claim 1, wherein the rotating element is oriented horizontally or vertically.

13. 10. The reactor of claim 1, further comprising a regenerative oxidant feed configured to react with the carbon buildup.

14. 14. The reactor of claim 13, wherein the regenerative oxidant feed is configured to change a structural characteristic of the carbon buildup when reacted with the carbon buildup, thereby weakening the carbon buildup.

15. 14. The reactor of claim 13, wherein the first surface and / or the second surface are configured to remove at least a portion of the carbon buildup remaining after the regenerative oxidant supply.

16. 1. A pyrolysis system comprising: a pyrolysis reactor comprising a pyrolysis chamber configured to produce a product stream from a system feed, the system feed comprising a hydrocarbon reactant, and the product stream comprising hydrogen gas and solid carbon; a regenerative oxidant feed, the pyrolysis reactor configured to react the regenerative oxidant with carbon buildup in the pyrolysis chamber to produce a regenerated product stream output from the pyrolysis reactor, the regenerative oxidant feed configured to remove a first portion of the carbon buildup via oxidation; a mechanical removal mechanism, the mechanical removal mechanism configured to remove a second portion of the carbon buildup.

17. 17. The pyrolysis system of claim 16, wherein the regenerative oxidant changes the structural characteristics of the carbon buildup when reacted with the carbon buildup, resulting in a weakening of the carbon buildup.

18. 20. The system of claim 17, wherein only one of the system feed and the regenerative oxidant is configured to be in the pyrolysis reactor at a time.

19. 18. The system of claim 17, wherein the mechanical removal mechanism is configured to operate while the system feed is being supplied to the pyrolysis chamber and / or while the regenerative oxidant feed is being supplied to the pyrolysis chamber.

20. The mechanical removal mechanism includes: a rotating element including a first surface; a second surface spaced apart from the first surface, wherein in operation: the first surface and / or the second surface are positioned to receive the second portion of the carbon accumulation; 18. The system of claim 17, wherein the first surface and / or the second surface are configured to remove at least a portion of the second portion of the carbon buildup as the rotating element rotates.

21. 20. The system of claim 17, further comprising an exhaust treatment system downstream of the pyrolysis reactor, the exhaust treatment system configured to partially and / or completely decarbonize the regeneration product stream using a reverse regeneration reaction.

22. 20. The system of claim 17, further comprising a heat source configured to cool and / or heat the carbon accumulation in the pyrolysis reactor above a standard pyrolysis temperature and then return the carbon accumulation to the standard pyrolysis temperature.

23. 1. A pyrolysis reactor configured to produce a product stream from a system feed, the system feed comprising a hydrocarbon reactant, the product stream comprising hydrogen gas and solid carbon, the reactor comprising: a first rotatable tube including an outer surface; a second rotary tube including an inner surface, wherein the first rotary tube and the second rotary tube are coaxial and non-concentric; a pyrolysis chamber between the outer surface of the first rotary tube and the inner surface of the second rotary tube, wherein the pyrolysis of the system feed is configured to occur within the pyrolysis chamber, wherein during operation: the first rotary tube is positioned to receive the solid carbon that accumulates on the outer surface, and the second rotary tube is positioned to receive the solid carbon that accumulates on the inner surface, resulting in carbon buildup on the outer surface and the inner surface; The rotation of the first rotary tube and the second rotary tube is configured to remove at least a portion of the carbon buildup.

24. 24. The reactor of claim 23, wherein the first rotary tube and the second rotary tube are configured to rotate in opposite and / or counter-rotating directions.

25. 24. The reactor of claim 23, wherein the first rotating tube and / or the second rotating tube are configured to stop rotation and / or reverse direction of rotation based on at least one of sensor feedback and a time interval.

26. 24. The reactor of claim 23, wherein the pyrolysis chamber is a crescent-shaped volume.

27. the reactor comprises a heat source configured to heat the first rotary tube and the second rotary tube; heating the first rotary tube and the second rotary tube is configured to heat the pyrolysis chamber; 24. The reactor of claim 23, wherein the first rotary tube and the second rotary tube are configured to transfer heat to the system feed as the system feed flows along the length of the pyrolysis chamber.

28. 24. The reactor of claim 23, wherein at least a portion of the carbon buildup is removed in a narrow gap between the outer surface of the first rotary tube and the inner surface of the second rotary tube.

29. 24. The reactor of claim 23, wherein the first rotary tube and the second rotary tube are inclined at an angle relative to the horizontal.

30. 24. The reactor of claim 23, further comprising a metal end adapter assembly on each end of the first rotary tube and the second rotary tube, the metal end adapter assembly comprising a metal adapter sleeve and an intermediate annular element.

31. the metal adapter sleeve is concentrically disposed around the first rotary tube and / or the second rotary tube with an annular gap between the metal adapter sleeve and the first rotary tube and / or the second rotary tube; 31. The reactor of claim 30, wherein the intermediate annular element is disposed within the annular gap.

32. 24. The reactor of claim 23, wherein the first rotary tube and the second rotary tube comprise ceramic tubes comprising at least one of silicon carbide, alumina, mullite, and silicon nitride.

33. 24. The reactor of claim 23, wherein the first rotating tube and the second rotating tube are configured to rotate in an inert environment for an extended period of time.

34. 1. A method for removing carbon buildup from a pyrolysis system, the method comprising: providing a pyrolysis system, the pyrolysis system comprising: a pyrolysis reactor comprising a pyrolysis chamber configured to generate a product stream from a system feed, the system feed comprising a hydrocarbon reactant, the product stream comprising hydrogen gas and solid carbon, at least a portion of the solid carbon accumulating within the pyrolysis reactor resulting in carbon accumulation; a regenerative oxidant feed, the regenerative oxidant feed configured to react with the carbon buildup; a mechanical removal mechanism; controlling the flow of the system feed through the pyrolysis reactor; controlling the flow of the regenerated oxidant feed through the pyrolysis reactor; and controlling movement of the mechanical removal mechanism, wherein the movement of the mechanical removal mechanism removes at least a portion of the carbon buildup.

35. controlling the flow of the system feed comprises: providing the system feed to the pyrolysis reactor when the pyrolysis system is in a pyrolysis mode; stopping the flow of the system feed through the pyrolysis reactor when the pyrolysis system is in a regeneration mode; controlling the flow of the regenerative oxidant supply comprises: stopping the flow of the regenerated oxidant feed through the pyrolysis reactor when the pyrolysis system is in the pyrolysis mode; supplying the regenerated oxidant feed to the pyrolysis reactor when the pyrolysis system is in the regeneration mode; Controlling the movement of the mechanical removal mechanism comprises:

35. The method of claim 34, comprising moving the mechanical removal mechanism when the pyrolysis system is in the pyrolysis mode and / or when the pyrolysis system is in the regeneration mode.

36. controlling an inert gas flow through the pyrolysis reactor, wherein controlling the inert gas flow comprises:

36. The method of claim 35, further comprising flowing the inert gas stream through the pyrolysis reactor between the pyrolysis mode and the regeneration mode and / or between the regeneration mode and the pyrolysis mode, wherein the inert gas stream purges gas from the pyrolysis reactor.

37. The pyrolysis reactor comprises: a first rotatable tube including an outer surface; a second rotating tube including an inner surface, the pyrolysis chamber being between the outer surface and the inner surface; the mechanical removal mechanism comprises the first rotary tube and the second rotary tube; Controlling the movement of the mechanical removal mechanism comprises:

35. The method of claim 34, comprising rotating the first rotatable tube and the second rotatable tube in opposite and / or counter-rotating directions.

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