Related Applications

[0001] The present application claims priority to United States Provisional Patent Application 63/331 ,051 entitled “Systems and Methods for Generating Hydrogen by Pyrolysis in a Dielectrophoresis (DEP) Supported Fluidized Bed Reactor” filed April 14, 2022, the entire contents of which are hereby incorporated by reference herein.

Technical Field

[0002] This disclosure relates generally to systems and methods for generating hydrogen gas and, more specifically, to systems and methods for generating hydrogen gas by catalytic and/or electromagnetically enhanced pyrolysis in a fluidized bed reactor.

Background

[0003] Hydrogen gas (H2) is commonly produced from natural gas via steam methane reforming and is commonly used to produce commodity chemicals and as fuel. In the production of hydrogen gas by steam methane reforming, carbon dioxide (CO2) is also produced as a by-product. New methods of producing hydrogen gas are needed where harmful chemicals, such as but not limited to CO2, are not produced.

[0004] Light hydrocarbon gas (primarily methane) pyrolysis can be used to generate hydrogen gas and solid carbon concurrently from the breaking down of the carbon-to-hydrogen bonds in the molecules. The reaction is CH4 (g) 2H2 (g) + C (s), and it is highly endothermic with overall enthalpy of 74.8 kJ/mol at equilibrium. The biggest obstacle of methane decomposition is the high activation energy (312 to 450 kJ/mol) of the reaction, which requires the reaction to be in the range of 1 ,000 °C to 1 ,200 °C. Catalysts such as nickel, cobalt and iron are commonly used in the reaction as the metals can reduce the reaction temperature down to 600 °C - 900 °C range, as the catalysts decrease the reaction's activation energy. Due to the endothermic nature of methane pyrolysis, reaction temperature plays a vital role in maximizing methane conversion and reaction kinetics. The higher the reaction temperature, the higher the reaction rates and the higher the methane conversion to hydrogen gas and carbon. Besides that, according to Le Chatelier's principle, the reaction equilibrium will be shifted to the product side and ultimately promote methane conversion at low pressure as there is more hydrogen gas than methane in the reaction.

[0005] Pyrolysis, or the thermochemical decomposition of hydrocarbons, offers the potential for generating hydrogen gas because it can be performed in an inert environment, typically at temperatures ranging between 300°C and 1 ,200°C. In some examples of pyrolytic processes, hydrogen gas can be produced from the decomposition of methane. This process generally emits few greenhouse gases (GHGs) because the decomposition of methane to hydrogen gas yields only solid carbon and, notably, does not produce CO2.

[0006] Fluidized bed reactors, or just fluidized beds, are commonly used to carry out multiphase chemical reactions. In this type of reactor, a gas is passed through solid particles that act as a catalyst. When the gas passes through the particles at a flow rate that suspends the particles, the latter behaves like a fluid. The minimum velocity of the gas that results in the suspension of the particle is known as a minimum fluidization velocity or rate.

[0007] Fluidized beds comprising magnetic particles are often used to drive high- temperature chemical reactions. To produce a fluidized bed that contains magnetic particles, the magnetic particles are disposed upon a substrate and then sintered together. During the sintering process, however, the particles that form the substrate fuse together to produce a clump that has a very low surface area and that can no longer be fluidized.

[0008] Fluidized bed reactors offer great potential as systems for generating hydrogen gas. In a fluidized bed reactor system, the gas entering the system must have a velocity equal to or greater than a minimum fluidization value to achieve optimum mixing of the particles within the fluidized bed and the reactant gas entering the system. The minimum fluidization velocity is the superficial gas velocity at which the drag force of the upward moving gas becomes equal to the weight of the particles in the bed. At the minimum fluidization velocity, the fluidized bed particles start to mix around to achieve efficient solid-gas contact, which promotes an efficient reaction, such as but not limited to efficient methane decomposition. In many systems, further mixing is provided with gas bubbles that are created in the system at a higher gas velocity, often mentioned as minimum bubbling velocity. At velocities lower than the minimum fluidization rate, the bed, or particles therein, act like a fixed bed where the reaction efficiency is lower than desired. In contrast, at a higher velocity than the minimum fluidization rate, the particles will be fluidized within the system; however, the solid-gas contact on the face of the particles will not be as efficient as at the minimum fluidization rate due to a decreased residence time between the gas and catalyst particles.

[0009] Current methods that directly decompose hydrocarbons produce large amounts of solid carbon and require a high reaction temperature. Many strategies have been developed highlighting and assessing the methane decomposition technologies using solid catalysts, including metals, metal enhanced carbons, and activated carbons to reduce the reaction temperature. The conclusions lead to the rapid deactivation of solid catalysts, which requires a catalytic reaction and the high-power requirements and low pressures of hydrogen gas produced in plasma-type systems. For example: a) U.S. Pat. No. 10,991 ,490 teaches methods of creating a monolithic bed that comprises chains of a first particle that is magnetic or that can be influenced by a magnetic field (such as iron) and a second particle that is not influenced by a magnetic field (such as silica), an electrical field or a combination of magnetic fields and electrical fields. The iron and silica particles are fluidized in a fluidized bed reactor using steam as the fluid. Then, a magnetic field is applied to the fluidized bed reactor and freezes the iron particles into place according to the direction of the magnetic field while the non-magnetic particles are sandwiched in between the iron particles. The temperature of the fluidized bed reactor is then elevated to a temperature of about 600° C to promote sintering of the iron particles. By stabilizing and fluidizing the bed of iron particles using a uniform magnetic field and sintering the particles around the non-magnetic particles to form the monolithic solid, it forms a high porosity, high surface area monolithic solid that is very favorable for conducting high reactivity chemical reactions. b) U.S. Pat. App. Pub. No. 2018/0062190 discloses systems, apparatuses, and methods for generating electric power via conversion of water to hydrogen and oxygen by steam plasma electrolysis. The system also includes a boiler that boils the water to create steam. From there, the steam travels into a magnetic catalyst chamber. Condensates are trapped via a condensate trap. The steam that is not caught by the condensate trap proceeds to a rechargeable catalytic hydrogen fuel cell (RCHFC). The RCHFC contains a cellular fluidized bed for the reduction of alumina to recharge the aluminum gallium alloy catalyst. c) U.S. Pat. No. 8,092,778 discloses a method to generate hydrogen-enriched fuel and carbon nanotubes using microwave-assisted methane decomposition. d) W.O. Pat. App. Pub. No. 2021/195566 discloses systems and methods to generate hydrogen gas and carbon via methane pyrolysis by heating a fluidized bed. e) U.S. Pat. App. Pub. No. 2022/0073345 discloses a process of producing hydrogen gas in a ceramic-supported catalyst reactor where the catalyst is regenerated by using hydrogen to clean the carbon produced on the catalyst surface.

[0010] Accordingly, there is a need for improved systems and methods of producing hydrogen gas and carbon in a fluidized bed reactor that can continuously remove the produced carbon deposited on the catalyst surface and extend the catalyst's usability lifetime.

Summary

[0011] In accordance with a broad aspect, a system for generating hydrogen gas and solid carbon from a feed stream comprising a hydrocarbon gas is described herein. The system includes a fluidized bed reactor configured to receive the feed stream and direct the feed stream through a bed of particles therein to fluidize the bed of particles. The feed stream has a velocity of about or below the minimum fluidization velocity of the bed of particles in the reactor. The feed stream also has a temperature sufficient to initiate a pyrolytic reaction between the hydrocarbon gas and particles of the bed of particles to produce a product stream comprising hydrogen gas and solid carbon. The fluidized bed reactor includes a chamber housing the bed of particles therein, the bed of particles including dielectric particles. The fluidized bed reactor also includes a plurality of electrodes configured to generate a non-uniform electric field having a gradient of strength across the chamber. The gradient initiates dielectrophoresis on the dielectric particles within the chamber to promote fluidization of the dielectric particles.

[0012] In at least one embodiment, the hydrocarbon gas is methane or another light hydrocarbon gas.

[0013] In at least one embodiment, the reactor chamber comprises high-frequency solenoid coils surrounding the chamber housing the particles.

[0014] In at least one embodiment, the electrode is positioned within an outer wall of the reactor.

[0015] In at least one embodiment, the electrode is positioned within the chamber of the reactor.

[0016] In at least one embodiment, the electrodes are configured to generate a modulated electric field that controls movement of the particles within the chamber.

[0017] In at least one embodiment, the electrodes are embedded in one or more dielectric materials to facilitate uniform distribution of arcing.

[0018] In at least one embodiment, the feed stream has a velocity at about or below the minimum fluidization velocity of the bed of particles.

[0019] In at least one embodiment, the particles include catalyst particles and noncatalyst particles.

[0020] In at least one embodiment, the particles each have a solid sphere or sphere-like shape.

[0021] In at least one embodiment, the catalyst particles include a spherical shell and a catalyst material positioned on an outer surface of the shell. [0022] In at least one embodiment, the catalyst particles comprise one or more conductive materials.

[0023] In at least one embodiment, the catalyst particles comprise nickel (Ni), cobalt (Co), iron (Fe) and its alloys, or activated carbon.

[0024] In at least one embodiment, the non-catalyst particles are ceramic particles and comprise silicon carbide (SiC) or silicon nitride (SisN4).

[0025] In at least one embodiment, the non-catalyst particles remove carbon from the catalyst particles by means of collision and abrasive action.

[0026] In at least one embodiment, the catalyst particles are about 20 wt. % to about 50 wt. % of the particles.

[0027] In at least one embodiment, the non-catalyst particles are about 50 wt. % to about 80 wt. % of the particles.

[0028] In at least one embodiment, the catalyst particles have an average particle size in a range of about 30 pm to about 125 pm.

[0029] In at least one embodiment, the non-catalyst particles have an average particle size of about 50 pm to about 150 pm.

[0030] In at least one embodiment, the electrical current is modulated to control a temperature of the fluidized bed reactor and arcing conditions within the fluidized bed reactor.

[0031] In at least one embodiment, the particles are configured to initiate micro arcing when present in the electric field.

[0032] In at least one embodiment, the particles are directly heated by the electromagnet (EM) energy to achieve the reaction temperature.

[0033] In at least one embodiment, the fluidized bed reactor is at a temperature in a range of about 300 °C to about 1 ,200 °C.

[0034] In at least one embodiment, the fluidized bed reactor is at a temperature of about 600 °C, and the particles include catalyst particles comprising Ni. [0035] In at least one embodiment, the fluidized bed reactor is at a temperature of about 900 °C, and the particles include catalyst particles comprising Fe.

[0036] In at least one embodiment, the fluidized bed reactor is at a temperature of about 1 ,200 °C, and the particles comprising of silicon carbide.

[0037] In at least one embodiment, the system also includes a cyclone configured to receive the product stream and separate the product stream into a solids product stream comprising solid carbon and particles and a gas product stream comprising hydrogen gas.

[0038] In at least one embodiment, the system also includes a heat exchanger configured to receive an inlet hydrocarbon gas stream and the gas product stream and provide for heat from the gas product stream to transfer to the inlet hydrocarbon gas stream.

[0039] In at least one embodiment, the gas product stream has a temperature in a range of about 300 °C to about 1 ,600 °C.

[0040] In at least one embodiment, the system also includes a carbon separator configured to receive the solids product stream and separate the solids product stream into a solid carbon stream and a cleaned particles stream, the cleaned particles being subsequently directed into the fluidized bed reactor.

[0041] In at least one embodiment, the dielectrophoresis decreases a weight requirement of the particles to be suspended and fluidized in the reactor.

[0042] In at least one embodiment, the particles each have a spherical shell and are configured to have a volume-to-weight ratio that reduces the minimum fluidization velocity.

[0043] In at least one embodiment, the particles each have a spherical shell and are configured to have a volume-to-weight ratio that provides for the dielectrophoresis to primarily suspend and fluidize the particles in the reactor.

[0044] In at least one embodiment, the particles include: non-catalyst particles having a hollow, spherical shell; catalyst particles having a hollow, spherical shell and a catalyst material positioned on an outer surface of the hollow, spherical shell; non-catalyst particles having a solid spherical shape and made of a ceramic-metal matrix material; and non-catalyst particles having a hollow, spherical shape and made of a ceramic-metal matrix material.

[0045] In accordance with another broad aspect, a method of generating hydrogen from a feed stream comprising a hydrocarbon gas is described herein. The method includes: providing the feed stream to a fluidized bed reactor; directing the feed stream through particles within a chamber of the fluidized bed reactor at a rate sufficient to fluidize the particles within the chamber and at a temperature sufficient to initiate a pyrolytic reaction between the hydrocarbon gas and the particles that produces hydrogen gas and solid carbon, the particles including dielectric particles, the fluidized bed reactor having an electrode configured to generate a non-uniform electric field having a gradient of strength across the chamber, the gradient initiating dielectrophoresis on the dielectric particles within the chamber to promote fluidization of the dielectric particles; collecting a product stream comprising hydrogen gas and solid carbon; and separating the product stream comprising hydrogen gas and solid carbon into a hydrogen gas product stream and a carbon product stream.

[0046] These and other features and advantages of the present application will become apparent from the following detailed description taken together with the accompanying drawings. It should be understood, however, that the detailed description and the specific examples, while indicating preferred embodiments of the application, are given by way of illustration only, since various changes and modifications within the spirit and scope of the application will become apparent to those skilled in the art from this detailed description.

Brief Description of the Drawings

[0047] For a better understanding of the various embodiments described herein and to show more clearly how these various embodiments may be carried into effect, reference will be made, by way of example, to the accompanying drawings that show at least one example embodiment which are now described. The drawings are not intended to limit the scope of the teachings described herein.

[0048] FIG. 1 is a schematic diagram of a system for generating hydrogen, according to at least one embodiment described herein.

[0049] FIG. 2 is a schematic diagram of a portion of a fluidized bed reactor having an electrode of a system for generating hydrogen, according to at least one embodiment described herein.

[0050] FIG. 3 includes front views and cross-sectional views of particles of a fluidized bed reactor of a system generating hydrogen, according to at least one embodiment described herein.

[0051] FIG. 4 is a schematic diagram of a portion of an electrode of a system for generating hydrogen showing dynamic micro arcing between particles within a fluidized bed reactor, according to at least one embodiment described herein.

[0052] FIG. 5A is an example of a modulated electric field for use with the systems and methods of generating hydrogen described herein.

[0053] FIG. 5B is an example of a modulated electric field for use with the systems and methods of generating hydrogen described herein.

[0054] FIG. 50 is an example of a modulated electric field for use with the systems and methods of generating hydrogen described herein.

[0055] FIG. 6 is a schematic diagram of a portion of a fluidized bed reactor of a system generating hydrogen with a plurality of electrodes, according to at least one embodiment described herein.

[0056] FIG. 7 is a schematic diagram of a portion of an electrode of a system for generating hydrogen, according to at least one embodiment described herein.

[0057] FIG. 8 is a schematic diagram of a portion of another electrode of a system for generating hydrogen, according to at least one embodiment described herein. [0058] FIG. 9A is a top view of an asymmetric electrode of a system for generating hydrogen, according to at least one embodiment described herein.

[0059] FIG. 9B is a top view of another asymmetric electrode of a system for generating hydrogen, according to at least one embodiment described herein.

[0060] FIG. 90 is a top view of another asymmetric electrode of a system for generating hydrogen, according to at least one embodiment described herein.

[0061] FIG. 10 is a schematic diagram of a portion of a fluidized bed reactor of a system for generating hydrogen having a plurality of electrodes, according to at least one embodiment described herein.

[0062] FIG. 11 is a schematic diagram of a portion of a fluidized bed reactor of a system for generating hydrogen having a neutral electrode, according to at least one embodiment described herein.

[0063] FIG. 12 is a schematic diagram of a portion of a fluidized bed reactor of a system for generating hydrogen having a neutral electrode, according to at least one embodiment described herein.

[0064] Further aspects and features of the example embodiments described herein will appear from the following description taken together with the accompanying drawings.

Detailed Description

[0065] Various apparatuses, methods and compositions are described below to provide an example of at least one embodiment of the claimed subject matter. No embodiment described below limits any claimed subject matter, and any claimed subject matter may cover apparatuses and methods that differ from those described below. The claimed subject matter is not limited to apparatuses, methods and compositions having all the features of any one apparatus, method or composition described below or to features common to multiple or all the apparatuses, methods or compositions described below. It is possible that an apparatus, method, or composition described below is not an embodiment of any claimed subject matter. Any subject matter that is disclosed in an apparatus, method or composition described herein that is not claimed in this document may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicant(s), inventor(s) and/or owner(s) do not intend to abandon, disclaim, or dedicate to the public any such invention by its disclosure in this document.

[0066] Furthermore, it will be appreciated that for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth to provide a thorough understanding of the example embodiments described herein. However, it will be understood by those of ordinary skill in the art that the example embodiments described herein may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the example embodiments described herein. Also, the description is not to be considered as limiting the scope of the example embodiments described herein.

[0067] It should be noted that terms of degree such as "substantially," "about," and "approximately" as used herein mean a reasonable amount of deviation of the modified term such that the result is not significantly changed. These terms of degree should be construed as including a deviation of the modified term, such as 1 %, 2%, 5%, or 10%, for example, if this deviation does not negate the meaning of the term it modifies.

[0068] Furthermore, the recitation of any numerical ranges by endpoints herein includes all numbers and fractions subsumed within that range (e.g., 1 to 5 includes 1 , 1.5, 2, 2.75, 3, 3.90, 4, and 5). It is also to be understood that all numbers and fractions thereof are presumed to be modified by the term "about," which means a variation up to a certain amount of the number to which reference is being made, such as 1 %, 2%, 5%, or 10%, for example, if the result is not significantly changed.

[0069] It should also be noted that, as used herein, the wording “and/or” is intended to represent an inclusive - or. That is, “X and/or Y” is intended to mean X, Y or X and Y, for example. As a further example, “X, Y, and/or Z” is intended to mean X or Y or Z or any combination thereof. Also, the expression of A, B and C mean various combinations, including A; B; C; A and B; A and C; B and C; or A, B and C.

[0070] The following description is not intended to limit or define any claimed or yet unclaimed subject matter. Subject matter that may be claimed may reside in any combination or sub-combination of the elements or process steps disclosed in any part of this document, including its claims and figures. Accordingly, it will be appreciated by a person skilled in the art that an apparatus, system, or method disclosed in accordance with the teachings herein may embody any one or more of the features contained herein and that the features may be used in any combination or sub-combination that is physically feasible and realizable for its intended purpose.

[0071] Recently, there has been a growing interest in developing new systems and methods of generating hydrogen gas.

[0072] Herein, systems and methods for generating hydrogen are described. The systems and methods generally provide for transforming hydrocarbons (i.e., molecules comprised primarily of carbon and hydrogen atoms) to hydrogen molecules (H2) and elemental carbon (also referred to herein as solid carbon), which can be sequestered without the emission of carbon dioxide to the atmosphere.

[0073] In at least one embodiment, the systems and methods described herein utilize one or more electromagnetic fields to fluidize a fluidized bed reactor to convert hydrocarbons within a feed stream into hydrogen molecules.

[0074] In at least one embodiment, the systems and methods described herein utilize a fluidized bed reactor that includes particles that may include a mixture of catalyst particles and non-catalyst particles. In at least one embodiment, utilizing a mixture of catalyst particles and non-catalyst particles may provide for the catalyst particles to remain clean within a chamber of the fluidized bed reactor (e.g., the non-catalyst particles may rub against and/or encourage collisions between particles within the chamber and thereby remove materials from an outer surface of the catalyst particles within the fluidized bed reactor). [0075] In at least one embodiment, the systems and methods described herein utilize micro-arcing within the fluidized bed reactor to provide energy to initiate and/or maintain a reaction therein. Specifically, in at least one embodiment, the dynamic distribution of conductive and/or semi-conductive particles creates an arcing pattern within the fluidized bed reactor that is constantly changing. The arcing pattern may be created in the volume of the fluidized bed reactor rather than between two specific electrodes and fluid.

[0076] In at least one embodiment, the systems and methods described herein utilize particles within a fluidized bed reactor that are/remain fluidized at or near a minimum fluidized or bubbling velocity to obtain an optimum methane decomposition rate by optimizing a contact efficiency between methane from the feed stream and particles within the fluidized bed reactor. In at least one embodiment, the particles within the fluidized bed reactor include but are not limited to metal particles with catalytic properties, such as but not limited to nickel, cobalt, iron, and their alloy(s), that reduce the reaction temperature (e.g., in a range of about 300°C to 1 ,200°C). Herein, metal particles with catalytic properties are referred to as “catalyst particles.”

[0077] In at least one embodiment, in the systems and methods described herein, the catalyst (e.g., metal) particles experience rapid deactivation by carbon produced within the fluidized bed reactor.

[0078] In at least one embodiment, the systems and methods described herein utilize a non-uniform electric field and dielectrophoresis (DEP) applied to a bed of particles that are fluidized by a gas at or near a minimum fluidization velocity. DEP is a phenomenon in which a force is exerted on a dielectric particle when subjected to a non- uniform electric field. This force does not require the particle to be charged. All particles exhibit dielectrophoretic activity in the presence of inhomogeneous electric fields. DEP may increase the residence time of hydrocarbons (e.g., methane) within the fluidized bed reactor, therefore increasing contact with catalyst particles within a chamber of the fluidized bed reactor. Herein, the term “minimum fluidization velocity” refers to a superficial gas velocity at which a drag force of an upward moving gas becomes equal to a weight of the particles in the bed.

[0079] In at least one embodiment, the systems and methods described herein utilize dynamically changing micro arcs within a fluidized bed reactor to encourage the conversion of hydrocarbons into hydrogen gas.

[0080] In at least one embodiment, the systems and methods described herein utilize particles that may absorb heat from an electromagnetic (EM) field, thereby providing heat within the systems at selectable locations.

[0081] In at least one embodiment, the concept with DEP described herein relies on establishing a gradient of an electric field strength. The DEP force will align or counteralign with the gradient depending on the dielectric parameters of the particles within the chamber and background materials. In at least one embodiment, DEP may provide for “suspending” particles dynamically within the fluidized bed reactor. Herein, the term “dynamically” refers to the notion that the force suspending the particles can be adjusted by, for example, adjusting a strength of the electric field. Further, in dynamic suspension, utilizing DEP means that, as the particles are being subjected to this force, a gas flow (which is at approximately or close to the minimum fluidization velocity) keeps the particles within the fluidized bed reactor moving, colliding and mixing, which provides for maintaining the gas rate low enough to achieve high methane to hydrogen conversion. The introduction of the DEP will cause the particles to shake by imposing an envelope on the electromagnetic field that can modulate the electric field. For example, the field exists within a set of electrodes then proceeds to exist in another set of electrodes. In return, the fluidized bed particles will move up and down within the envelope of the electromagnetic (EM) field.

[0082] In at least one embodiment, at least some of the particles within the fluidized bed reactor may be formed of a material that is effective in removing carbon formation on the surface of the particle. For example, sintering may occur when metals are heated to a high enough temperature, which is undesirable. The fusion between two colliding particles may be inhibited by maintaining the particles in constant motion within the fluidized bed reactor.

[0083] In at least one embodiment, the systems and methods described herein include one or more electrodes that generate a non-uniform electric field. The non-uniform electric field may have a gradient pointing in a chosen direction. The non-uniform electric field having the gradient pointing in the chosen direction may be generated using an appropriately shaped electrode or a combination of appropriately shaped electrodes or the combination of variably shaped electrodes. The non-uniform electric field having the gradient pointing in the chosen direction may also be generated by establishing a resonant electromagnetic field in a cavity that creates appropriate electric field distribution.

[0084] Turning to the figures, one example of a system 100 for generating hydrogen gas is shown schematically in FIG. 1. In system 100, a feed stream 103 is provided to a fluidized bed reactor 104, having a chamber 105 therein.

[0085] Fluidized bed reactor 104 comprises one or more electrodes 106 for generating an electric field therein. As noted above, in at least one embodiment, electrode 106 is configured to generate a non-uniform electric field having a gradient.

[0086] Fluidized bed reactor 104 also comprises particles 108. Particles 108 are housed in chamber 105 of reactor 104 and are free to move therein. In at least one embodiment, high-frequency solenoid coils surround chamber 105.

[0087] The electric field generated by electrode 106 creates a DEP force that is exerted on each of the particles 108 housed in the fluidized bed reactor 104 due to the gradient of the electric field, which is present due to the non-uniform ity of the electric field. In at least one embodiment, the direction of the gradient of the electric field acting on the particles may be in any direction, provided that the gradient exerts a force onto the particles.

[0088] In at least one embodiment, the electric field may be an alternating current (AC) electric field. In at least one embodiment, the electric field may be a direct current (DC) electric field. In at least one embodiment, the electric field may be a combination of an AC electric field and a DC electric field. The AC electric field may have additional beneficial effects on the process as it could provide direct heating to the particles during the reaction, and the arcing initiated during the process may be controlled more easily in an AC electric field environment. A combination of AC and DC electric fields may leverage the properties of each electric field source in the reactor.

[0089] In at least one embodiment, reactor 104 may include means to elevate a temperature within the reactor 104 and/or to control a temperature within the reactor 104. In at least one embodiment, the means may provide for elevating and/or controlling the temperature within an entire volume of the reactor 104, or optionally directly within arcs. For example, the means may be provided by simple heating, by solenoid heating (such as but not limited to by high-frequency solenoid coils surrounding chamber 105), or through electromagnetic interaction of EM fields with particles 108 and/or any other reactor materials, as well as though the arcing process.

[0090] FIG. 2 shows one example of an electric field produced by an electrode 106, according to at least one embodiment described herein. In this example, the gradient is represented by the arrow pointed in the upward direction. Here, the strength of the gradient decreases in the upward direction as the electric field, represented by the gradient lines in FIG. 2, generated by the electrodes becomes more uniform or parallel.

[0091] In at least one embodiment, electrode 106 may be embedded in one or more dielectric materials to facilitate uniform distribution of arcing (e.g., similar to dielectric barrier discharge plasma), which also protects the electrodes.

[0092] In at least one embodiment, combining a DEP force generated by the gradient of the electric field with fluid flow of a gas (from feed stream 103), for example, at a minimum fluidization rate or below a minimum fluidization rate, from a lower end 106a of electrode 106, particles 108 within chamber 105 are fluidized (e.g., upwardly) in a controlled manner while increasing the gas-solid residence time for the reaction to take place between the hydrocarbons within the gas and the catalyst particles 108. [0093] In at least one embodiment, the particles 108 comprise catalyst particles and non-catalyst particles. In at least one embodiment, the particles 108 have the same size. In at least one embodiment, the particles 108 have variable sizes. In at least one embodiment, the particles 108 have a size in a range of about 1 pm to about 300 pm , or in a range of about 15 pm to about 200 pm , or in a range of about 30 pm to 125 pm. In at least one embodiment, the particles 108 are of different types and have variable sizes and masses. In at least one embodiment, the particles 108 have a combination of hollow ceramic spheres and catalyst coated hollow ceramic spheres. In at least one embodiment, the particles 108 are of solid and hollow ceramic metal matrix particles.

[0094] In at least one embodiment, as the particles 108 are fluidized, they rearrange themselves according to their size and/or weight and/or dielectric properties. For example, the particles 108 may rearrange so that larger particles move downwardly, and smaller particles move upwardly within chamber 105. Accordingly, this may result in the biggest particles being present at a lower end 105a of chamber 105 and the size of the particles 108 getting progressively smaller from the lower end 105a of chamber 105 towards the upper end 105b.

[0095] As noted above, particles 108 may comprise non-catalyst particles and catalyst particles.

[0096] In at least one embodiment, the non-catalyst particles may include ceramic particles, having for example, a spherical shape with radius, rd (see, for example, FIG. 3), comprising materials such as but not limited to silica carbide (SiC) or silicon nitride (Si3N4). As noted above, the non-catalyst particles may provide for abrasion of the particles within chamber 105 and breaking of micro arcs, for example.

[0097] In at least one embodiment, the catalyst particles, also having for example, a spherical shape with radius, r _c (see, for example, FIG. 3), may comprise materials such as but not limited to nickel (Ni), cobalt (Co), iron (Fe), and their alloys, or activated carbon. In at least one embodiment, the catalyst particles may be ceramic particles (as described above) that are coated with a metal such as but not limited to the metals noted above. In at least one embodiment, the catalyst particles may be hollow metal spheres. In at least one embodiment, the catalyst particles may be SiC particles.

[0098] By adjusting the radius rd and r _c or the composition of a shell of particles 108, the DEP force exerted by the gradient of the electric field may be controlled.

[0099] Some catalyst particles, such as but not limited to catalyst particles comprising Ni and/or Fe, may tend to exhibit loss (i.e., dissipate electromagnetic field power, and convert it to heat) when exposed to the electromagnetic field (e.g., the AC electric field) as the catalyst particles have at least one of high magnetic permeability, p, of non-zero, non-infinite electric conductivity. Further, some catalyst particles may be heated until they reach the Curie point temperature that stabilizes the electromagnetic, EM, absorption, as upon reaching the Currie point, their magnetic interaction will rapidly diminish. This may lead to self-regulation of the process. For example, catalyst particles interact in chamber 105 in two ways: i) directly with the hydrocarbons (e.g., methane) of the feed stream 103 to trigger methane decomposition at a reaction temperature, for example, about 600 °C with catalyst particles comprising Ni and about 900 °C with catalyst particles comprising Fe; and ii) through dynamic micro-arcing (DMA), which is shown in FIG. 4.

[00100] DMA between catalyst particles within chamber 105 may be controlled. For example, it may be controlled by controlling the movement of the particles 108, by controlling interactions between the particles 108, and by varying electric field parameters.

[0100] In at least one example, controlling the DMA may inhibit the melting of particles 108 and/or inhibit the sintering of particles 108 within chamber 105.

[0101] In at least one example, controlling the DMA may provide for controlling a reaction temperature of the particles 108 because particles 108 tend to absorb heat from the electric field to reach the reaction temperature.

[0102] It will also allow arcs to develop (further increase in temperature and direct pyrolysis through arc). Multiple processes require careful regulation and balancing. [0103] In at least one embodiment, particles 108 may have piezoelectric properties, and the interaction with the electric field may generate acoustic waves in the system 100, for example to that will serve to mix, create collisions and/or to break arcs.

[0104] In at least one embodiment, the system 100 may include one or more piezoelectric materials (e.g., one or more plates, meshes, gratings, etc.) within the one or more electrodes 106 and/or within chamber 105 of reactor 104.

[0105] In at least one embodiment, the electric field may be modulated with an envelope. Modulating the electric field may promote particle movement (“shaking”) to induce collisions between the particles and, in some instances, may promote cleaning of catalyst particles (e.g., by knocking off any carbon generated and collected on an outer surface of the catalyst particles). Examples of modulated electric fields are shown schematically in FIGs. 5A, 5B and 5C.

[0106] FIG. 6 shows an example arrangement of a plurality of electrodes 106a for generating more than one (e.g., two) electric fields. In this example, one electric field is generated by Ri - Li and one electric field is generated by R2 - L2. In this example, the two electric fields can operate simultaneously or separately. The two electric fields operating separately result in force changes and oscillations of particles 108 within the electric fields. In this example, generating two electric fields with different electrodes and operating them separately (e.g., turning on the electric field generated by R1 - Li when the electric field generated by R2 - L2 is off, and vice versa), result in “shaking” the particles 108. In other examples, the electric field generated by R1 - Li and the electric field generated by R2 - L2 do not need to be “on” and “off”, respectively. The shaking of the particles 108 may be achieved through any amplitude modulation. It should be noted that the square and circle shapes in FIG. 6 are for illustration only.

[0107] Again, as noted above, the shape of the electrode(s) 106 may take many different forms. For example, sharp edges on the electrode may be avoided, such as in the example shown in FIG. 7A, to avoid singular effects of the electric fields. This may also be done with symmetric electrode configuration, where the electrodes are disposed on the outside of the reactor or the inside. For example, FIG. 7A shows an example of an electrode 106 having a cylindrical outer shell 110 with a shaped core 1 12. The outer shell 110 is grounded, and the shaped core 112 does not contain any sharp edges. In at least one embodiment, the core 112 may be grounded. In at least one embodiment, the shell 110 may be shaped to not contain any sharp edges.

[0108] FIG. 8 shows an electrode 106 having a plurality of electrodes 106a therein generating a voltage between the shell 110 and shaped core 112. Herein, a plurality of voltages can be generated (designated with V1 , V2, V3, ... , VN). In one example, when V1 > V2 > V3 > ... > VN, a gradient of voltages can be generated. A gradient of voltages may be generated on the inside or on the outside of the electrode 106. Additionally, individual electrodes 106 may be individually shaped to maintain the gradient.

[0109] In at least one embodiment, electrode 106 may have an asymmetric shape that, for example, may add an electric field gradient in the form of hoops. For example, FIG. 9A shows one embodiment of electrode 106 having a plurality of lobes 116 where an asymmetric electric field gradient is generated. The asymmetric gradient is shown in FIG. 9A in dotted lines representing a circumferential direction. In this example, by carefully switching or phasing, particles 108 may circulate within chamber 105.

[0110] In at least one embodiment, one or more hooped gradients may be combined with one or more vertical gradients to initiate helical particle movement within chamber 105. In at least one embodiment, helical movement of particles 108 may also be achieved with appropriate distribution of electrodes and field excitation.

[0111] FIG. 9B shows another arrangement of an electrode 106 according to an exemplary embodiment. In FIG. 9B, electrode 106 is arranged in two phases having four poles labelled N, S, E and W. In this example, any pair of poles can be excited.

[0112] FIG. 9C shows another arrangement of an electrode 106 according to an exemplary embodiment. In FIG. 9C, electrode 106 is arranged in three phases having six poles labelled P1 , P2, P3, P4, P5, and P6. In this example, the excited pairs may include P1 - P4, P2 - P5 and P3 - P6. When electrode 106 is arranged in three phases, there is a 120-degree phase difference. With the 120-degree phase difference, a rotating electric field can be created by switching a pair at a time. The rotation of the pairs will create the rotating gradient corresponding to the swirling field. As a result, the shift in pair during the rotation will also shift the position of the particle. In a complete repeating cycle, the particles will circulate along the field. The same effect can be obtained by using different pairs which are operating at a different frequency. Other arrangements are also possible, such as but not limited to arrangements with a 6-degree phase difference or a 60-degree phase difference.

[0113] Additionally, according to at least one embodiment described herein, electrode 106 may be arranged to provide one or more lateral gradients to promote lateral movement of particles 108. One example of an electrode 106 having lateral gradients is shown in FIG. 10.

[0114] FIG. 10 also shows an example embodiment of electrode 106 having a mixed gradient. The dominant gradient is pointing upward and is represented by dotted lines generated from the square electrodes. However, FIG. 10 also shows that horizontal gradients that can be turned on and off can be introduced to add lateral movement and increase the path of interaction.

[0115] Additionally, an electrode may be introduced into the chamber 105 to further refine the shape of the electric field. One example of such an electrode 106 having a neutral core 117 is shown in FIG. 11. Note that both gradients can be created with the same electrode system by using different generators simultaneously. In FIG. 11 , electrode 106 may be made by including piezo-electric materials, which will be excited by the electric field. The electric field will create acoustic waves inside the chamber 105.

[0116] In at least one embodiment, both electrodes may be axially symmetric and connect the source between the electrodes, such as is shown in FIG. 7 and FIG. 8.

[0117] FIG. 12 shows another example of an electrode 106 of a system for generating hydrogen. Therein, a center ground conductor 118 is provided with a high potential electrode 119 positioned towards the outside of chamber 105. The center ground conductor 118 may be at a high potential (e.g., AC or DC or both) and grounded in the outer high potential electrode 119. [0118] Returning to the system 100 of FIG. 1 , feed stream 103 typically enters the reactor 104 at a bottom end 104a and the gas of feed stream 103 flows upwardly through chamber 105. In some cases, carbon may encapsulate some of the catalyst particles, which will affect the particle fluidization behaviour due to a change in mass of the particles within the chamber 105. With the change in mass and the decreasing hydrogen production due to catalyst deactivation, the system flow rate can be increased so that the particles can exit the reaction chamber 105 to be separated and cleaned, as shown in FIG. 1.

[0119] Specifically, carbon produced during the pyrolysis inside chamber 105 is lifted upwardly by the feed stream gas. The catalyst particles within chamber 105 and carbon can flow outwardly from a top end 104b of reactor 104 as product stream 120 into a cyclone 121 .

[0120] Cyclone 121 separates the catalyst particles and carbon as a solids product stream 122 and the H2, residual methane and other hydrocarbons as a gas product stream 124. The solids product stream 122 is passed to a carbon separator 125, producing a solid carbon stream 126 and a cleaned particles stream 127. The cleaned particles of the cleaned particle stream 127 can be recycled back to reactor 104.

[0121] Gas product stream 124 is optionally passed to a heat exchanger 128 that removes heat therefrom, provides heat to stream 102 and produces feed stream 103. Cooled gas product stream 129 is then passed to a gas separator 130 that separates the H2 from the residual methane and other hydrocarbons to produce an H2 product stream 131 and a residuals stream 132. Residuals stream 132 may optionally be fed back to reactor 104 (e.g., bottom end 104a thereof).

[0122] In an alternate embodiment, carbon produced in chamber 105 during pyrolysis may fall downwardly within chamber 105. In this case, feed stream 103 may be configured to enter reactor 104 from a side thereof, and a filter (not shown) may be provided within chamber 105 to provide for carbon to be collected at bottom end 104a of reactor 104. [0123] In another alternate embodiment, where the carbon produced does not encapsulate the catalyst particles but rather detaches itself from the particles after the reaction and floats together among the particles, electrode 106 could be switched off, and carbon could fall to the bottom of the reactor and be flowed out, leaving the catalyst particles in the reaction chamber.

[0124] While the applicant's teachings described herein are in conjunction with various embodiments for illustrative purposes, it is not intended that the applicant's teachings be limited to such embodiments as the embodiments described herein are intended to be examples. On the contrary, the applicant's teachings described and illustrated herein encompass various alternatives, modifications, and equivalents, without departing from the embodiments described herein, the general scope of which is defined in the appended claims.