Hydrocarbon pyrolysis via joule heating of powder

Abstract

Systems and methods for producing hydrogen, or gaseous mixtures containing a substantial proportion of hydrogen, by electrical pyrolysis of hydrocarbons, and, more particularly, electrical pyrolysis of methane to produce hydrogen or gaseous mixtures containing a substantial proportion of hydrogen via the use of joule heating of powders and gases. The systems and methods utilize joule heating of powders and gases to enable thermal decomposition of the gases in a volume of electrically conductive powder that is confined inside a joule heated reactor. The systems and methods can be used in the thermal decomposition of methane gas into at least hydrogen gas and carbon inside a reactor, wherein the methane is infused within a volume of gas permeable electrically conductive powder and the heat for the thermal decomposition is provided by joule heating the powder.

Description

HYDROCARBON PYROLYSIS VIA JOULE HEATING OF POWDERThis application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 629,967, which was filed on October 11, 2023.Field of the Invention

[0001] This invention relates to systems and methods for producing hydrogen, or gaseous mixtures containing a substantial proportion of hydrogen, by electrical pyrolysis of hydrocarbons, and, more particularly, electrical pyrolysis of methane to produce hydrogen or gaseous mixtures containing a substantial proportion of hydrogen via the use of joule heating of powders and gases.Description of the Related Art

[0002] Methane pyrolysis systems include molten salt pyrolysis, where methane gas is bubbled through a molten salt media and undergoes thermal decomposition of methane into hydrogen and carbon. Other methane pyrolysis systems include plasma or microwave induced pyrolysis in which the methane is cracked by plasma energy. Other methane pyrolysis systems include quartz tube ovens where the methane is heated indirectly by radiation from resistive wire filament. In many systems, there is a need for a catalyst to be present in the reactor to improve the efficiency of the methane cracking. In all such systems, methane pyrolysis is not energy efficient due to lack of good thermal energy transfer from the heater to the methane.

[0003] Methane pyrolysis can be done with three common methane paralysis systems and processes. Figure lA-left shows a hot filament pyrolysis system. With this apparatus, the gas flows in a closed reactor tube and the hot filament can either be outside of the tube or inside the tube. Such an approach is limited as it utilizes a very small hot surface area per unit volume of the reactor and lacks efficient heat transfer from the filament to the gas. Figure lA-middle shows molten media pyrolysis system. This approach utilizes molten salts and catalyst that have to be kept in liquid state and gas is then bubbled through the molten salt to crack the methane into hydrogen and carbon. Such an approach is limited as it experiences catalyst saturation and deactivation that require molten salt replenishment that is not easy to scale. In addition, theresulting carbon has low value because it is contaminated by the catalyst. Figure lA-right shows a plasma assisted pyrolysis system. This approach utilizes vacuumized reactors in which gas is turned into plasma with the help of electrical power. The methane in the plasma field then decomposes into hydrogen and carbon. Some limitations of this approach are the capital and operating costs, and the limited throughput constrained by the plasma reaction volume that can practically be constructed.

[0004] PCT International Publication No. WO / 2022 / 246325 to Wang et al. discloses a system wherein the heating element is placed inside an oven where the heat transfer between the heating element and the methane gas is improved locally. However, the heating element of this disclosure is a thin heating element made from carbon fibrils. A limitation of this system is that methane pyrolysis is restricted to localized areas near the heated thin element (carbon fibrils). Figure IB shows an embodiment of this methane pyrolysis apparatus and this system also lacks scalability.

[0005] A flash joule heating synthesis of graphene is disclosed in PCT International Publication No. WO 2020 / 051000 to Tour et al., where electrically conductive solid carbon material is flash joule heated with electrical power to convert the solid carbon into solid graphene. This disclosure does not teach methane pyrolysis, does not teach hydrocarbon pyrolysis, and does not teach gas pyrolysis.Summary Of The Invention

[0006] The current invention comprises gas pyrolysis using Joule Heating, in which material powders, including a conductive additive powder, and gases, are rapidly heated using Joule Heating, causing thermal decomposition of the gas, or thermally activated chemical reactions of the gas with at least some of the powder, or the combination of both, resulting in desired products, such as for example hydrogen and various carbon materials, that are then collected.

[0007] One embodiment of the current invention is a method for thermal decomposition of methane gas, comprising infusing the methane gas within a volume of gas permeableelectrically conductive powder and heating the conductive power by joule heating to cause the thermal decomposition.

[0008] Another exemplary embodiment of the current invention is a method for thermal decomposition of methane inside a sealed reactor wherein the methane decomposes into at least hydrogen and carbon as it flows through a volume of joule heated carbon-based powder.

[0009] Another exemplary embodiment of the current invention is a method for thermal decomposition of methane inside a sealed reactor wherein the methane decomposes into at least hydrogen and carbon as it flows through a volume of joule heated carbon-based powder while the powder is being mixed.

[0010] Another exemplary embodiment of the current invention is a method of joule heating a powder, comprising joule heating an electrically conductive powder in a vacuum inside a bucket reactor.

[0011] Another exemplary embodiment of the current invention is a system for thermal decomposition of gas comprising: a reactor capable of containing a volume of electrically conductive powder; a mechanism for flowing gases through said powder; and electrodes for joule heating said powder.

[0012] Another exemplary embodiment of the current invention is a system for joule heating powders, comprising: a graphite bucket reactor having ceramic bottom for holding conductive powder; and a stationary rotating electrode inserted into the bucket that can mix the powder, wherein electrical power can be applied between the electrode and the graphite bucket to joule heat the powder.

[0013] Another exemplary embodiment of the current invention is a system for joule heating of powders, comprising: a graphite bucket reactor for holding conductive powder comprising: a gas outlet port; a ceramic bottom; a gas tight lid that can slide over the bucket and that is electrically insulated from the bucket; and a moving electrode inserted into the bucket that can mix the powder; wherein electrical power can be applied between the electrode and the graphite bucket to joule heat the powder.

[0014] Another exemplary embodiment of the current invention is a system for joule heating powders, comprising: a graphite bucket reactor for holding conductive powder; and a rotating assembly comprising an electrode and electrically insulating stirring paddles, wherein the electrode is electrically insulated from the bucket bottom, and wherein the rotating assembly is inserted into the bucket to mix the powder, wherein electrical power can be applied between the electrode and the graphite bucket to joule heat the powder.

[0015] Another exemplary embodiment of the current invention is a system for joule heating powders, comprising: a graphite tube reactor for holding conductive powder, having a removable electrically insulating bottom; and a rotating assembly comprising of an electrode and electrically insulating stirring paddles, wherein the electrode is electrically insulated from the bucket bottom, and wherein the rotating assembly is inserted into the bucket to mix the powder, wherein electrical power can be applied between the electrode and the graphite bucket to joule heat the powder.

[0016] Another exemplary embodiment of the current invention is a system for joule heating powders, comprising: a graphite bucket reactor for holding conductive powder; and a movable graphite electrode, having an electrically insulating cup at its end, to insulate the electrode from the reactor bottom, the movable graphite electrode inserted into the reactor to mixthe powder, wherein electrical power can be applied between the electrode and the graphite reactor to joule heat the powder.

[0017] Another exemplary embodiment of the current invention is a system for joule heating powders, comprising: a graphite tube reactor for holding conductive powder, the graphite tube reactor having removable bottom; and a movable graphite electrode inserted into the reactor to mix the powder, wherein electrical power can be applied between the electrode and the graphite reactor to joule heat the powder.

[0018] Another exemplary embodiment of the current invention is a method for thermal decomposition of gas, comprising: providing a volume of electrically conductive powder; permeating the volume of electrically conductive powder with a gas; wherein the gas comprises hydrogen and carbon; and joule heating the electrically conductive powder.

[0019] Another exemplary embodiment of the current invention is a method for a thermally activated chemical reaction of gas and a reactant powder, using joule heating, comprising: combining the reactant powder with an electrically conductive powder; joule heating the combined reactant powder and electrically conductive powder; and flowing the gas through a volume of the combined reactant powder and electrically conductive powder; for the gas to undergo a thermally activated chemical reaction with the reactant powder.

[0020] The systems according to the present invention can comprise many different features as described below. These and other aspects and advantages of the invention will become apparent from the following detailed description and the accompanying drawings which illustrate by way of example the features of the invention.Brief Description of the Drawings

[0021] The drawings included herewith are for illustrating various examples of articles, methods, and systems of the present specification.

[0022] FIG. 1 shows a prior art methane pyrolysis apparatus.

[0023] FIG. 2 shows an example of methane pyrolysis per the invention, where the pyrolysis is enabled by joule heating of a volume of powder, confined within a tube reactor, permeated with the methane gas.

[0024] FIG. 3A shows a continuous batch process system for electrical methane pyrolysis, including the powder replenishing process steps.

[0025] FIG. 3B shows a continuous batch process system for electrical methane pyrolysis, including the electrical pyrolysis process step.

[0026] FIG. 4A shows a side view of an electrical methane pyrolysis system incorporating loose powder inside a conductive bucket reactor.

[0027] FIG. 4B shows a top view of an electrical methane pyrolysis system incorporating loose powder inside a conductive bucket reactor.

[0028] FIG. 5A shows a side view of an electrical methane pyrolysis system incorporating paddle-stirred loose powder inside a conductive bucket reactor.

[0029] FIG. 5B shows a simplified version of a side view of an electrical methane pyrolysis system incorporating paddle-stirred loose powder inside a conductive bucket reactor.

[0030] FIG. 5C shows a simplified version of a top view of an electrical methane pyrolysis system incorporating paddle-stirred loose powder inside a conductive bucket reactor.

[0031] FIG. 5D shows a side view of an electrical methane pyrolysis system incorporating a tube reactor, a removable bottom, and a powder stirring assembly.

[0032] FIG. 5E shows a simplified version of a top view of an electrical methane pyrolysis system incorporating a tube reactor, a removable bottom, and a powder stirring assembly.

[0033] FIG. 6 shows a side view of a continuous electrical methane pyrolysis system incorporating paddle-stirred loose powder in a conductive bucket reactor with continuous powder replenishment capability.

[0034] FIG. 7A shows a continuous electrical methane pyrolysis system incorporating paddle-stirred loose powder in a conductive bucket reactor with continuous powder replenishment capability. The figure shows the top view of the no-powder-flow shutter position.

[0035] FIG. 7B shows a continuous electrical methane pyrolysis system incorporating paddle-stirred loose powder in a conductive bucket reactor with continuous powder replenishment capability. The figure shows the top view of the powder-flow shutter position.

[0036] FIG. 8A shows a side view of an electrical methane pyrolysis system incorporating loose powder stirring with an independent paddle in a conductive bucket reactor.

[0037] FIG. 8B shows a top view of an electrical methane pyrolysis system incorporating loose powder stirring with an independent paddle in a conductive bucket reactor.

[0038] FIG. 9A shows an electrical methane pyrolysis system incorporating independent paddle loose powder stirring in a conductive bucket reactor with an offset round electrode.

[0039] FIG. 9B shows an electrical methane pyrolysis system incorporating independent paddle loose powder stirring in a conductive bucket reactor with an offset oval electrode.

[0040] FIG. 10A shows an electrical methane pyrolysis system incorporating a bucket reactor system with a moving capped electrode.

[0041] FIG. 10B shows an electrical methane pyrolysis system incorporating a removable bottom tube reactor system with a moving capped electrode.Detailed Description

[0042] Various systems or processes will be described below to provide examples of the claimed embodiments. No embodiment or embodiments described below are intended to limit any claimed embodiment, and any claimed embodiment may cover processes or system in addition to or that differ from those specifically described. The claimed embodiments are not limited to systems or processes having all of the features of any one system or process described, or to features common to some or all of the systems described.

[0043] The description of this disclosure teaches embodiments of innovative methods of gas pyrolysis, more specifically hydrocarbon pyrolysis, and even more specifically methane pyrolysis. Gas pyrolysis refers to the process of thermal decomposition of a gaseous molecule into smaller, simpler gas molecules by heating a gas in the absence of oxygen. Hydrocarbon pyrolysis is a thermal decomposition process where large hydrocarbon molecules are broken down into smaller, simpler hydrocarbon fragments by applying high temperatures in the absence of oxygen. Methane pyrolysis is a chemical process that breaks down methane (CH4) into hydrogen (H2) and solid carbon at high temperatures. This process is also known as methane cracking or methane decomposition. Embodiments of this innovation will be described with a methane pyrolysis as an example but the embodiments equally apply to thermal decomposition of hydrocarbons and other gases, including thermal decomposition of organic compound gas that also contains oxygen or nitrogen in addition to carbon and hydrogen.

[0044] The teaching of this disclosure enables the fabrication of all carbon nanostructures, including amorphous carbon, crystalline carbon, nanostructured sp2 carbonforms, such as graphene, fullerene, and carbon nanotubes, stacked graphene such as graphite, and their combinations and variations.

[0045] Graphene and graphite consists of sp2 carbon hexagonal networks of carbon atoms with covalent bonding between C atoms within a layer, and a weak van der Waals interaction between adjacent layers. Graphite is defined as 3-D layered material formed by stacking more than 10 single-layer graphene layers of 2-D graphene. In this disclosure, the term graphene refers to a layered crystalline carbon structure with up to 10 layers. Layered structures of more than 10 layers are referred to as graphite, as is well known to those experienced in the relevant art. Both graphene and graphite may be ordered (stacked) or disordered (turbostratic), referring to the order of adjacent layers in the structure. While this paragraph discusses the difference between graphene and graphite, and stacked and disordered carbon arrangements, it does not limit any embodiment disclosed herein to a specific arrangement.

[0046] Figure 2 illustrates one embodiment of this innovation in which methane gas, in direct contact with a volume of joule heated powder, is converted into hydrogen and carbon inside a sealed reactor. A sealed reactors refers to a reactor that is isolated from the outside environment, but may allow inlet and outlet of process gases. The heat for the thermal decomposition is provided by joule heating of the electrically conductive powder confined within the reactor. Bulk powder has low packing density such that it is gas permeable and allows the voids to be filled (infused) with gas such as methane. The volume of the powder can but does not have to completely fill the volume of the reactor, and may instead partially fill the reactor volume with powder. In one example, the powder can fill 75% of the reactor volume of Figure 2, leaving void space above the powder volume. One example of electrically conductive powder can comprise carbon powder. One example of a reactor can comprise a sealed quartz tube reactor.

[0047] The conversion of methane into hydrogen and carbon can also be described as pyrolysis. The pyrolysis conversion can also be applied to other hydrocarbons or mixture of hydrocarbons. The pyrolysis conversion can also be applied to other gaseous or vaporized liquid organic compounds of hydrocarbons. The pyrolysis of this embodiment can occur while the methane is static (does not flow) with respect to the volume of joule heated powder, or themethane can flow through the volume of joule heated powder. Static methane implies that a desired methane volume is pumped inside the reactor, such that the methane is being held inside the reactor with the inlet and outlet valves closed, while the thermal decomposition of the methane occurs, after which the hydrogen is released from the reactor by opening the outlet valve. These steps can be repeated as needed. The flow of methane can be continuous, variable, or intermittent. Continuous flow implies that prescribed rate of methane, for example in units of cubic centimeters per minute, moves continuously from the inlet valve of the reactor towards the outlet valve of the reactor while the methane undergoes thermal decomposition as its molecules travel through the reactor, and where both the inlet and outlet valves are open. The methane flow can also be variable, where the flow rate changes as a function of time or reactor temperature or some other metric, as may be convenient or needed for an efficient process. The methane flow can also be intermittent, where the methane flow can be stopped and then resumed, as may be convenient or needed for an efficient process.

[0048] In the embodiment shown in FIG. 2, a methane gas 201 is provided from an inlet into a gas feeder 202 that regulates the methane flow rates and can switch between inlet sources. Methane 201 is fed into reactor 206 via gas feedthrough 218. The reactor is filled with an electrically conductive powder 207 that is confined and compressed into tube reactor 206 by two graphite electrodes 204, one on each side of the tube. Powder compression can include compacting the powder. When the reactor is partially filled, the electrodes may rest at the open ends of the reactor and the powder is not compressed. O-ring 205 may be employed to better seal the inside of the reactor from the atmosphere and vice versa. Graphite electrodes 204 have an opening that allows the penetration of the inlet gas feedthrough 218 into the reactor and penetration of the outlet feedthrough 214 that allows the resulting gas / solids to be removed from the reactor. The graphite electrodes 204 are connected to electrical power sources 203 and 208 to provide power to joule heat the electrically conductive powder 207. Inside reactor 206, during the thermal decomposition process, the methane decomposes into hydrogen 217 and solid carbons 216, 219, 220. One result of the thermal decomposition process of methane may be solid carbon 216 that can deposit itself onto the carbon powder. Another carbon form from the process may be free solid carbon 220 that settles inside the reactor, and is not attached tothe carbon powder 207. Or it may form flowable solid carbon 219 (fine dust or "fines") that can flow with hydrogen gas 217. During normal operation, it may also be expected that some methane does not decompose and thus may leave the reactor as unprocessed methane 215. The resulting process components, hydrogen 217, flowable solid carbon 219 (fine dust or fines), and unprocessed methane 215, that may be called gas / fines stream, flow out from the reactor (or it is being pumped out) through outlet feedthrough 214 and into the optional carbon separator 209, where the fine solid carbon 219 is removed from the gas / fines stream using tools and techniques known in the art of exhaust treatment. It may then be sent to carbon outlet 213 and collected in a bin. One example of a fine carbon removal tool is a cyclone dust collector but others can be used. After the carbon is removed, the remaining gas stream now only comprises of hydrogen and small amounts of unprocessed methane, and may be piped to a hydrogen separator 210 where hydrogen is separated from unwanted hydrocarbons or other residual gases and is then sent to a collection tank via hydrogen outlet 211. The unprocessed methane 215 can optionally be sent back to gas feeder 202 for further reuse or it can be collected separately.

[0049] One advantage of having powder as the heating element instead of metal wire filaments, carbon paper, carbon cloth, or other bulk heating elements, is that powders have greater surface area per gram than wires, paper, or cloth. The typical surface area of carbon cloth is from 0.1 to 2 m2 / g while carbon powders have surface area from 1 to 100 m2 / g. Higher surface areas of the powder are also possible. The surface area of the direct contact between the methane and the powder is at least an order of magnitude greater, which allows, for example, for better heat transfer from the powder to the gas, better thermal efficiency, faster decomposition time, and greater volumetric utilization of the reactor volume.

[0050] Another advantage of a powder heater vs a classical heating element is that the heat transfer from the hot powder to the methane gas is due to local radiation heat and local conduction heat transfers. Because each grain is a micro-heater that radiates and conducts heat to the gas in its vicinity, powder heaters greatly improve the heat transfer efficiency.

[0051] Another advantage of a powder heater is that ohmic resistance between powder grains allows for lower bulk resistance which in turn helps improve the practical implementation of the joule heater operation. Other joule heating elements, such as carbon cloth, have very lowresistance that makes them operate at much higher currents. It is desirable for the powder to be electrically conductive in the order of 1 to 1000 Ohms (bulk resistance) in order to be joule heated using existing industrial utilities having 120 to 480 Volts and current rating of 1 to 1000 Amperes. Other voltages and current ratings are also applicable.

[0052] The conductive powder 207 may include carbon materials with low impurities (low ash, low sulfur, low volatiles) and may include at least one of the group comprised of, but not limited to: calcinated petroleum coke, metallurgical coke, carbon black, activated carbon, char, graphene, flash graphene, carbon nanotubes, carbon nanofibers, carbon fiber, or graphitized carbon fiber. The residue from these conductive powders will be minimal. Depending on the process temperature (controlled by the power of the joule heating) the low impurity conductive powders will improve their crystallinity and become more graphitized with each use. The applied joule heating power can be selected to be low so that it will not substantially change the carbon powder crystallinity. On the other hand, the applied joule heating power can be selected to induce substantial changes to the powder crystallinity. In another case, the powder crystallinity may already be already high so that even a high power joule heating will not substantially change the crystallinity. The amorphous carbon or partially graphitized carbon in the conductive powders may, for example, convert into graphite, turbostratic graphite, graphene, turbostratic graphene, polyhedral graphite, polyhedral graphene, turbostratic polyhedral graphite, turbostratic polyhedral graphene, carbon nanotubes and nanofibers, or graphitized fibers. For example, non-crystalline amorphous carbon may be changed to crystalline graphene orgraphite, or polycrystalline (partially crystallized) carbon black may be changed to crystalline (fully crystallized) graphene or graphite. A substantial change of crystallinity (graphitization) means changing from one crystallinity state to another (from one graphitization state to another), such as for example from amorphous to fully crystalline (from partially graphitized to fully graphitized). Not a substantial change of crystallinity (graphitization) means that the crystallinity state (graphitization state) remains largely unchanged.

[0053] The conductive powder 207 may also include carbon materials with higher impurities (ash, sulfur, volatiles) such as: anthracite coal, green petroleum coke, asphaltenes, recycled-tire carbon black, bio char, wood char, plant char, paralyzed cellulose, conductivepolymer, conductive plastic, plastic char, plastic ash, and a combination thereof. The residue from these conductive powders will be higher than the low purity carbon but that will not affect the hydrogen purity. Depending on the process temperature, the higher impurity conductive powders will improve their crystallinity and become more graphitized with each use, resulting in conversion to graphite, turbostratic graphite, graphene, turbostratic graphene, polyhedral graphite, polyhedral graphene, turbostratic polyhedral graphite, turbostratic polyhedral graphene, carbon nanotubes and nanofibers, or graphitized fibers.

[0054] The conductive powder 207 in the embodiments of the present invention can include all possible morphologies including for example: powder, grain, pellets, chunks, spherelike, hollow sphere-like, particles, spheres, nanospheres, microspheres, rods, nanotubes, nanowires, microwires, microfibers, matrix-forming structures, or any combination thereof. The conductive powder 207 includes all material structures, including for example: non-porous, porous, nanoporous, microporous, and having layered structures. The conductive powder 207 in the embodiments of the present invention can include all powder sizes, including for example from a few nanometers to a few millimeters. In one embodiment , the conductive powder 207 is Met Coke with grain sizes from 0.5 to 3 mm and surface area of 1-3 m2 / g, in another example the conductive powder 207 is Carbon Black with prime particle size of 30 nm and structure size of about 1 pm, and surface area of 20-40 m2 / g.

[0055] The carbon-based conductive powder 207 may also include a non-conductive filler that may decompose during the methane pyrolysis process and produce additional hydrogen, additional carbon formation and morphologies (graphite, graphene, nanotubes, nanofibers and any combination thereof), and additional oxygen or nitrogen byproducts. Examples of such non- conductive fillers include high density polyethylene, low density polyethylene, polypropylene, polystyrene, Styrofoam, polyethylene terephthalate (PET), polyacrylonitrile (PAN), plastics, waste plastics, cellulose, sugar, paraffins, urea, or any combination thereof. In addition, the carbon formations produced from the non-conductive fillers like plastics may form carbon composites with the carbons from the methane decomposition. Examples of connected carbon composites include, for example, graphite, graphene, and / or nanotubes from the methane decomposition and graphite, graphene, and / or nanotubes from the plastics.

[0056] The carbon-based conductive powder 207 may also comprise metal-based catalysts that can facilitate the synthesis (from the methane) of additional 2D and 3D carbon formation and morphologies (graphite, graphene, polyhedral graphene, nano-onions, or any combination thereof), and ID carbon formations with high aspect ratios (nanotubes, nanofibers, nanobelts, or any combination thereof), or improve the yield of the additional carbon formation morphologies. Catalysts include but are not limited to: Fe, Co, Ni, Cu, other transition metals, iron acetate, iron chloride, metal chlorides, chlorides, iron acetylacetonate, iron oxide, cobalt oxide, other transition metal oxide, iron hydroxide, nickel hydroxide, other transition metal hydroxide, or any combination thereof. In addition, the carbon formations with high aspect ratios may form composites with the 2D and 3D carbon formations.

[0057] The carbon-based conductive powder 207 may also comprise silicon-based additives such as silicon, silicon dioxide, silicon oxide (SiOx), silicon carbide, or any combination thereof. The silicon-based additives may be in the form of nanospheres, microspheres, nanotubes, nanowires as well as any combination thereof. The silicon-based additives can facilitate the synthesis of silicon-based composites, including nanostructures that are covered or decorated with graphene, nanotubes, nanofibers, polyhedral graphene, nano-onions or any combination thereof. One example of a silicon-based composite is a silicon-based particle wrapped in graphene layers. The particle can be a sphere, hollow sphere, rod, wire, or have any other morphology. Another example of a silicon-based composite is silicon carbide.

[0058] Carbon-based conductive powder 207, such as transition metal oxides, transition metal carbides, or metals that alloy with Li, such as aluminum, bismuth, cadmium, magnesium, tin, antimony, and any combination thereof, may also comprise other additives that may form new carbon composites.

[0059] The conductive powder 207 may also be metal conductive powder, such as iron, nickel, cobalt, copper steel, and any combination thereof. The powder may also include metal shavings.

[0060] The pyrolysis process of this invention can also be applied to other gaseous hydrocarbons besides methane. Hydrocarbons are any of a class of organic chemicals comprisingthe elements carbon and hydrogen. The carbon atoms join together to form the framework of the compound, and the hydrogen atoms can attach in many different configurations. Other hydrocarbons include, but are not limited to, acetylene (C2H2), ethylene (C2H4), ethane (C2H6), and propane (CjHs). The pyrolysis in embodiments of the present invention can also be applied to natural gas which is known to include gases other than hydrocarbons. The pyrolysis of embodiments of the present invention can also be applied to liquid hydrocarbons like crude oil. Liquid hydrocarbons can be first vaporized before injecting them into the joule heated reactor. Alternatively, liquid may be injected in liquid form that vaporizes as it enters the heated powder near the inlet feedthrough / nozzle, and therefore infuses the rest of the heated powder as vapor. The pyrolysis of this invention can also be applied to any organic compound that contains carbon and hydrogen. The pyrolysis of embodiments of the present invention can also be applied to any organic compound that also contains oxygen or nitrogen in addition to carbon and hydrogen. Alcohols are a class of organic compounds that have one or more hydroxyl groups attached to a carbon atom of a hydrocarbon chain. One example of a liquid organic compound is alcohol that can be vaporized and injected into the joule heated reactor. The use of inert gases 221, such as Nitrogen or Argon may be used optionally.

[0061] In one embodiment of the innovation as described in Figure 2, the reactor is a sealed quartz tube. The reactor may be constructed from other materials such as ceramic (Nitride bonded silicon carbide - NB SiC, silicon carbide - SiC, aluminum nitride - AIN), high temperature steels (Hastelloy alloy, Inconel alloy, Nickel based allows), cement, concrete, SiC based refractories and aluminum-based refractories. The size of the reactor (diameter and length) from Figure 2 can depend on the desired throughput and power availability. In one example the reactor is a quartz tube with 6 in. diameter and 3 ft length, having a volume of 22 L. The reactor shape may be other than a tube, such as for example oval or rectangular.

[0062] In one embodiment, the steps of pyrolysis of methane by joule heating of a powder can include the following steps, but it understood that in other embodiments other steps can be included and the following steps may be in different order:

[0063] Step 1. Filling reactor 206 with conductive powder 207. In one example about 14 kg of MC conductive powder can fit into a 22 L tube reactor. In one exemplary case of a partiallyfilled reactor, about 10 kg of MetCoke (MC) may be filled into the 22 L tube reactor, optionally leaving some void space above the volume of powder.

[0064] Step 2. Sealing tube reactor 206 with two graphite electrodes 204 and applying compression (such as for example compacting) to powder 207. For a higher compression force applied, the powder volume resistance will be lower. Thus, the compression can be used to adjust the resistance of the powder. The electrodes are being moved towards each other inside the reactor (or at least one moved and another one being fixed) to compress the powder. As the powder gets compressed / pushed the bulk resistance of the powder changes in a nonlinear manner. After some point, any further force applied to the electrodes will not compress the powder any further and the resistance will not be changed. During the joule heating, the powder may expand or contract, so it is desirable to have spring loaded electrodes to compensate for the powder volume changes. For partially filled reactors, where the powder is not compressed (compacted), the volume of the powder determines the bulk resistance of the powder. O-rings 205 help seal graphite electrodes 204 to tube reactor 206, preventing hydrogen 217 from escaping reactor 206, and preventing oxygen and moisture from entering reactor 206.

[0065] Step 3. Optionally removing air and moisture from powder 207 from inside the sealed reactor 206 before starting the flow of methane gas 201. The purpose of the air removal is to remove residual oxygen trapped within the reactor so as to reduce carbon-oxygen reactions that can increase the volatility of the reaction and also produce unwanted CO2 gas. However, after the initial methane flow, the residual air and oxygen will automatically be displaced by the methane gas. Depending on the design of the reactor and the density of the powder 207, the methane flow can be in the exemplary range from 1 to 10000 seem. A mechanical vacuum in the range of 20 to 500 mbar provides sufficient air removal. The same task can be achieved by flowing an inert gas 221, such as Nitrogen, before stopping the Nitrogen and turning on the methane 201. The pyrolysis can be conducted with the pump pulling vacuum as the methane flows, or with the pump not operating after the initial pump down.

[0066] Step 4. Applying electrical power (203 and 208) across the two graphite electrodes 204 to apply joule heating to the powder 207 that will keep the temperature at a target range with the help of a power controller. The power for joule heating may be AC, DC, modified AC orDC, or any combination thereof. In some embodiments the joule heating power is automatically adjusted with the help of a controller to achieve a desired decomposition temperature which is set as a target. The exemplary target range for pyrolysis of methane is from 700 to 1300 C but the joule heating of powder can achieve temperatures up to 3000 C. The electrical power can be steady over time or it can be applied in pulses. Due to the fast reaction time of the joule heating process, the powder temperature will also follow the electrical power profile, allowing more flexibility in improving the efficiency of the methane pyrolysis process. In some embodiments, the joule heating power or temperatures can follow a prescribed profile, and in other cases, the controller automatically adjusts to achieve other target set points.

[0067] Examples of other set points include consideration of hydrogen purity, yield, or pressure. In one example, the purity of the hydrogen is measured with a sensor that provides closed loop control feedback to the joule heating controller which adjusts its power output to achieve the desired hydrogen purity set point. The joule heating controller can also adjust the power output applied to the conductive powder inside the reactor based on other sensor inputs, such as hydrogen yield, or reactor pressure due to hydrogen and other gases. The joule heating controller can also be an adaptive controller, or one that uses artificial intelligence that takes input from multiple sensor and / or process models to compute optimal power output. The controller output may include adjusting Power (Watts), Voltage (Volts), Current (Amperes), duty cycle of an AC power (%), pulse width (ms or sec), pulse pattern, or any combination thereof to control the heating intensity of the conductive powder in the reactor.

[0068] Step 5. Flowing methane 201 gas through reactor 206 will expose the gas to heat from powder 207 and will result in thermal decomposition of methane 201 into hydrogen 217 and solid carbon species 216, 219, and 220. In one embodiment, the gas 201 infuses and flows through the volume of gas permeable powder 207. In Another exemplary embodiment, where the powder 207 partially fills the reactor 206, part of the gas 201 infuses and flows through the powder 207 volume and part of the gas flows outside the powder volume and through the void space volume above the powder 207. In some embodiments, the gas 201 flows predominately outside the powder volume. The solid carbon 216, 219, and 220 may include amorphous carbon, graphitized carbon, crystalline carbon, graphene, turbostratic graphene, graphite, turbostraticgraphite, AB stacked graphite, ABC stacked graphite, carbon nanotubes, and nanofibers, as well as any combination thereof. One carbon species is solid carbon 216 that can deposit itself onto carbon powder 207 and will stay trapped within the reactor. Another carbon species is free solid carbon 220 that is not deposited / attached to the carbon powder 207 and will settle within the powder 207 and will stay trapped within the reactor. For embodiments where the powder partially fills the reactor, in the unfilled portion of the reactor there is extra volume, which may be occupied by the solid carbon species 216 and 220 in addition to the void volume within the gas permeable powder. When conductive powder 207 comprises a metal-based catalysts, then the solid carbon 216, 219, and 220 may react with the metal-based catalysts and form carbides or metal-carbon hybrid structures, or it may coat the metal-based catalysts with a solid carbon layer. When conductive powder 207 comprises silicon-based additives, then the solid carbon 216, 219, and 220 may react with the silicon-based additives and form silicon carbides or siliconcarbon hybrid structures, or it may coat the silicon-based additives with the solid carbon layer. For the pyrolysis of methane, for every four hydrogen atoms (25.1% on mass basis), a carbon atom (74.9% on mass basis) is released, and some fraction of the carbon will stay within reactor 206. Therefore, after generating a certain mass of hydrogen 217, the volume of the carbon inside the reactor will increase and will reduce the available powder surface area and will reduce the flow of the methane gas, thus requiring a periodical replacement of the powder within the reactor. Powder requiring replacement may be referred to as spent powder. Yet another carbon species is flowable solid carbon 219 (fine dust or fines) that is exhausted with the hydrogen. Some methane may not decompose and may leave the reactor as unprocessed methane 215. In one mode of operation, methane 215 continuously or intermittently flows through the reactor 206 until the powder 207 is saturated with carbon and has to be replaced. In another mode of operation, methane 201 flows into the reactor 206 until it fills its volume set gas pressure, then the methane 201 flow is stopped such that the methane is static, and the powder 207 is joule heated to decompose the methane 201 within the reactor.

[0069] Step 6. The resulting methane pyrolysis process components, hydrogen 217, flowable solid carbon 219 (fines), and unprocessed methane 215, that flow out from the reactor, can be further processed. In one process, the outlet stream is fed through a carbon separator209, where the flowable solid carbon 219 is removed from the gas / fines stream, using tools and techniques known in the art of exhaust treatment, and is being collected in a bin that may be open or closed to the atmosphere. The flowable solid carbon 219 may include amorphous carbon, graphitized carbon, crystalline carbon, graphene, graphite, carbon nanotubes, and nanofibers, as well as any combination thereof. The flowable solid carbon 219 may include metal-based catalysts in its structure or it may include silicon-based additives in its structure.

[0070] Step 7. The gas stream that was filtered from its carbon fines may be further processed. In one process, the outlet stream is fed through a hydrogen separator 210 where hydrogen is separated from unwanted hydrocarbons or other residual gases and is sent to a collection tank. The unprocessed methane 215 can optionally be sent back to gas feeder 202 for further reuse or it can be collected separately.

[0071] Figure 2 further discloses a batch process embodiment, where after some number of cycles or after some process time, the total volume of all the carbons inside the reactor (spent carbon) may increase due to the solid carbon formation from methane pyrolysis, which may require a periodical replacement of the powder within the reactor. Spent carbon refers to the total volume of conductive carbon powder and solid carbon formations inside the reactor. For an embodiment with partially filled powder, there is higher capacityforsolid carbons to be stored before the spent carbon inside the reactor has to be replenished.

[0072] Figure 3 illustrates one embodiment of present invention in which the methane pyrolysis process can be done in a continuous batch mode of operation to increase the process throughput. Continuous batch mode means that there is: 1. A joule heated pyrolysis step, 2. A used powder removal step, and 3. A fresh powder replenishment step, that can be executed repeatedly in a continuous mode. The pyrolysis step can be a single pyrolysis operation, or a continuous methane flow and methane pyrolysis operation, until the conductive powder needs replacement. Figures 3A and 3B illustrate a system where the reactor tube 206 from Figure 2 has been modified to include modified reactor tube 306 that includes conical reactor extensions 309 and 310, that allow fresh (pre-process) electrically conductive powder 322 to be filled into the reactor body 306, and used (post-process or spent) electrically conductive powder 323 to be removed from the reactor 306. The conical reactor extensions 309 and 310 can be any othershape that enables powder filling and removal. Figure 3A shows the open (filling-in) position of inlet graphite electrode 302 that allows refill with fresh conductive powder 322, as well as open (removal) position of graphite inlet electrode 304 that allows removal of the used (spent) conductive powder 232. Figure 3B shows the closed (pyrolysis) position of graphite electrodes 302 and 304 that enables the pyrolysis process to take place. One orientation of the system from Figure 3 may be vertical where the inlet 302 and outlet 304 graphite electrodes are up and down respectively, where gravity enabled filling and removal of the powder is possible. The reactor of Figure 3 may also have a tilted orientation that allows gravity to aid the filling and removal of the powder. In one example of a tilted reactor, the reactor makes a 45 degrees angle with the horizontal axis, or it may have a 10 degree angle with the horizontal axes as another example. A tilted reactor of Figure 3 may support a partially filled reactor where the powder is in contact with both electrodes and there is a void space above the powder.

[0073] While embodiments of the present invention are described herein as reactors and systems for gas pyrolysis and in general reactors and systems for joule heating of a powdered material, the reactors and system in this disclosure are described in exemplary orientations, and it is understood that the present invention applies equally to any reactor and system orientation, including horizontal, vertical and tilted.

[0074] For the filling operation to take place, the inlet graphite electrode 302 can be lifted to create a gap between the inlet graphite electrode 302 and the inlet conical reactor extension 309 that allows pre-processed powder to be filled into reactor body 306. The inlet conical reactor extension 309 also acts as a funnel to guide the fresh powder 322 into reactor 306. During the filling process, the exit of the reactor should be closed by positioning the exit graphite electrode 304 with its o-ring 311 to seal the exit conical reactor extensions 310 to prevent loss of powder from the reactor. Automated fill of the pre-process powder 323 can be done with powder moving equipment such as for example Piab vacuum systems or automatic powder feeders.

[0075] For the removal operation to take place, the exit graphite electrode 304 is lowered to create a gap between the exit graphite electrode 304 and the exit conical reactor extension 310 that allows post-processed powder to be removed from the reactor body 306. During theremoval process, the inlet of the reactor can be opened (as for filling) or it can be closed by positioning the inlet graphite electrode 302 with its o-ring 305 to seal the inlet conical reactor extensions 309. The removed post-process powder 323 can be collected into a bin that may be open or closed to the atmosphere. Further automated transport of the post-process powder 323 can be done with powder moving equipment such as for example a Piab vacuum systems or automatic powder feeders.

[0076] For the pyrolysis operation to take place, both the inlet graphite electrode 302 and the exit graphite electrode 304 should be closed to seal the conductive powder 307 inside reactor 306. O-rings 305 and 311, which are in contact with conical reactor extensions 309 and 310, prevent hydrogen gas 317 from escaping reactor 306, and prevent oxygen and moisture from entering reactor 306.

[0077] Compression using graphite electrodes 302 and 304 can be used to adjust the resistance of the conductive powder 307 as needed for optimal joule heating of the powder. The electrodes can be moved towards each other (or one towards the other) inside the reactor to compress the powder. As the powder gets compressed / compacted, the bulk resistance of the powder changes in a nonlinear manner. After some point, any further force applied to the electrodes will not compress the powder any further, and the resistance will not change further. Since, during joule heating, the powder may expand or contract, it is desirable to have spring loaded electrodes to compensate for the powder volume changes.

[0078] Figure 3B shows an exemplary embodiment where air is removed from reactor 306 before starting the flow of methane gas 301, followed by applying electrical power 303 and 308 across the two graphite electrodes 302 and 304 to apply joule heating to powder 307 that will keep the temperature at a target range with the help of a power controller. Flowing methane gas 301 through reactor 306 exposes the gas to heat from powder 307 and results in the thermal decomposition of the methane 301 into hydrogen 317 and solid carbon species 316, which may include: (a) solid carbon that deposits itself onto the carbon powder, (b) free solid carbon that is not deposited / attached to the carbon powder but stays trapped within the reactor and (c) flowable solid carbon (fine dust) that is exhausted with the hydrogen. It may also be expected that some methane may not decompose and may leave the reactor as unprocessed methane315. The output hydrogen and carbon stream 324 can optionally be fed through a carbon separator, where the flowable solid carbon is removed from the stream 324, and / or optionally fed through a hydrogen separator system where hydrogen is separated from unwanted hydrocarbons or other residual gases and is sent to a collection tank. The unprocessed methane 315 can optionally be sent back to mix with methane 301 for further reuse or it can be collected separately.

[0079] Embodiments of this innovation disclosed in Figures 2 and 3 may include compressing / compacting the powder within two graphite electrodes to achieve an optimal bulk powder resistance for applying joule heating to the powder. It may be desirable to have a system where compression / compacting to the powder is not needed (loose powder), while still being able to apply joule heating to the powder.

[0080] Figure 4 illustrates Another exemplary embodiment of the present invention comprising an electrically conductive graphite bucket 406 with an electrically insulating bottom 413 and an electrically conductive electrode assembly 404 positioned such that it is aligned with the vertical axes of the bucket 406 and such that it reaches the insulating bottom 413 at the bottom of the bucket 406, where the conductive powder 407 partially fills the graphite bucket 406 and makes an electrical connection with the electrode assembly 404 and bucket electrode 406 without the need for powder 407 compression. However, the powder may also be compressed (compacted) or non-compressed (non-compacted). Without the powder compression, the powder 407 electrical resistance is generally higher than when the powder is compressed. Higher power resistance is beneficial for better control of the joule heating. The electrically insulating bottom 413 may be a quartz disk. The system of Figure 4 further comprises a gas tight electrically insulating bucket lid 411, and an inlet gas feedthrough 418 fixed to the lid 411 to flow methane gas 401 inside the powder 407 and an outlet feedthrough 414 also fixed to the lid 411 to remove the hydrogen and carbon stream 424 from the pyrolysis process. The gas tight lid 411 isolates the reactor 405 from the outside environment, but allows inlet and outlet of process gases through inlet 418 and outlet 414 feedthroughs. Alternatively, the inlet and outlet feedthroughs may be mounted on the reactor walls. Gas inlet feedthrough 418 comprises an electrically insulating gas tube (for example, a quartz tube) that is inserted into powder 407and its end is positioned substantially near the bottom of the reactor 406 or substantially near the insulator bottom 413 without blocking the gas flow. In one example, the tube end is 5 mm from the bottom, but it may be nearer or flush with the bottom. Positioning the feedthrough tube closer to the bottom of the powder causes the injected gas to travel the longest path through the hot powder and / or spend the longest time infused within the powder to optimize the thermal decomposition of the gas. The longer the resident time inside the reactor, the higher the probability that the gas molecule will thermally decompose. The gas outlet feedthrough 414 comprises a gas tube (electrically conductive or insulating) that is open to the gas tight reactor, and its end is positioned substantially near the top of the reactor 406 without being inserted into the conductive powder 407. In one example, the tube end may be even with the bottom of the lid. The electrically insulating gas tight bucket lid 411 may be a quartz or ceramic structure and may be constructed from several components. The electrically conductive bucket 406 may also be constructed from other high temperature metal materials as described previously. The electrically conductive bucket 406 may have many shapes including for example circular, oval, square, rectangular, or polygonal cross section profile. The electrically conductive bucket 406 may have sidewalls that are not parallel to each other, and / or not perpendicular to the bottom or top of the reactor. For example, the reactor may have conical walls.

[0081] The electrical power 403 and 408 for methane pyrolysis via joule heating is applied to the powder 407 through electrode assembly 404 and bucket electrode 406. The electrode assembly 404 may rotate (or have rotational rocking motion) or it may be static (does not rotate). The electrode assembly 404 may move within the bucket volume in XYZ axes (carrying with itself a lid that allows sliding on top of the bucket without losing contact or exposing the reactor to the environment - not shown in the figure), preferably without contacting the bucket reactor walls, or it may be stationary with respect to the bucket (does not move). The graphite electrode assembly 404 of the embodiment from Figure 4 can be a simple rod, from top to bottom, or a more complex electrode comprising of a rod top and oval shaped bottom part. The top rod of the electrode assembly penetrates the gas tight bucket lid 411, making a gas tight mechanical seal 410 that allows optional rotation of the electrode assembly 404 but does not allow gas from inside bucket 406 to escape into the atmosphere. Likewise, the gas tight bucket lid 411 and itso-ring 405 seal the bucket 406 from the atmosphere. A lid that allows a sliding motion does not have parts that are inserted into the reactor, and may have o-rings that allow lateral (sliding) motion between the lid and top reactor walls without losing contact or exposing the reactor to the environment (design not shown in the figure). In one embodiment, the electrode assembly 404 has a rod shape, is stationary, and is not rotated. The electrical current path in the rod electrode configuration is radial from the rod electrode to the walls of the graphite bucket, producing a radial current density profile where the current density is higher near the rod electrode than at the walls of the bucket. Since the powder resistance is generally uniform, the temperature profile from the joule heating will follow the current density profile. One function of the electrically insulating bottom 413 is to force the electrical current to propagate towards the bucket walls rather than towards to bottom of the bucket.

[0082] Referring again to Figure 4, it may be desirable to mix the powder 406 to produce a more uniform temperature profile for the pyrolysis process. Mixing can occur as the thermal decomposition process is ongoing, or the mixing can occur during process pauses, or a combination of each approach. Mixing the powder means that grains comprising the powder are moved with respect to each other to randomize their relative position with respect to each other, and their absolute position within the reactor. One way to achieve the powder mixing is with a paddle shaped oval electrode, as shown in Figure 4B, that rotates. Preferably, the electrode assembly is positioned near the center of the lid. Another way of mixing is to rotate the reactor with respect to the paddle. The rotating electrode / bucket embodiment can be used for gas pyrolysis and for general joule heating of a powder, including converting joule heated powder to another state of matter.

[0083] Alternatively, the shape and size of the rotating paddle electrode can be different than shown in Figure 4B, and it can be asymmetric. For this configuration, it is preferred that the electrode comprise a rod top part and oval shaped bottom part, so that the top rod can be rotated through the gas tight bucket lid 411 and the gas tight mechanical seal 410, while the oval shaped bottom part can mix the powder 407. The electrical current path in the oval electrode configuration is radial from the edges of the rod electrode to the walls of the graphite bucket, producing a radial current density profile where the current density is higher near the rodelectrode than at the walls of the bucket. In addition, with an oval electrode shape, the electrical current is more focused in the direction of the long axis of the oval electrode, providing current density that is higher than with a cylindrical rod. In addition, the oval electrode provides a rotating current density and therefore a rotating heat profile. The above advantages of the oval electrode provide a more uniform and more concentrated heat profile that improves the efficiency of the methane pyrolysis process.

[0084] In Another exemplary embodiment, mixing the powder can comprise move the electrode (for example, rod electrode) in the XY axes with respect to the bucket. Generally, the XY plane is the bottom of the bucket, and the Z axis is in the direction of the bucket height. Lifting and inserting the electrode, in Z axis, in the powder can also achieve mixing. Further, moving the reactor instead of the electrode is also possible. Further, to achieve powder mixing with a moving electrode in the presence of a lid is possible, for example, if the lid diameter is approximately 2x the diameter of a cylindrical bucket and wherein the lid can slide (move laterally) with respect to the bucket without allowing gas interaction with the outside environment. In further embodiments, other lid arrangements are possible which allow the bucket seal remains intact. The gas inlet and outlet ports for this embodiment may also be mounted on the bucket rather than the sliding lid. The moving electrode / bucket embodiment can be used for gas pyrolysis and for general joule heating of a powder, including converting joule heated powder to another state of matter. During the joule heating of the powder, the reactor may operate using a vacuum or it may be filled with an inert gas. One advantage of joule heating the powder in a vacuum is the prevention of undesired arcing or plasma generation (current flow being diverted from flowing through the powder) in or around the powder.

[0085] In one embodiment, where the electrode assembly 404 is static (not rotating), the power source 403 may be directly connected to the electrode assembly 404. In Another exemplary embodiment, where the electrode assembly is rotating 409, the power source 403 may be connected to the electrode assembly 404 via electrical connector 402 that can pass a high current while electrically connected to an electrode shaft undergoing rotational motion 409. The rotational speeds of the rotating electrode of these embodiments may be in the range from 0.1 revolutions per minute (rpm) to about 10 rpm. Other rotational speeds are possible. Examplesof such an electrical connector 402 are a brush connector, a spring loaded rolling bearings connector, or other types of sliding connectors. One concern with electrical connectors is the wear of the electrode due to friction. Figure 4 describes a rotating electrode shaft made from graphite but a combination of graphite, brass, and / or copper is also possible. In one example, the graphite shaft may be covered with a brass sleeve that is more durable than a graphite contact. Other protective conductive elements are also possible.

[0086] The operation of the pyrolysis embodiment as shown in Figure 4 may be similar to the operation of the pyrolysis as disclosed in Figures 2 and 3. In the process of Figure 4, air may be removed from graphite bucket 406 initially, or the vacuum pumping may continue throughout the pyrolysis process. The continuous vacuum pumping can assure that the gas tight bucket lid 411 stays in firm contact with the graphite bucket 406 and that the hydrogen and carbon outlet stream is being sucked through the outlet feedthrough 414 more efficiently than through passive gas flow. The flow of methane gas 401 can be initiated before electrical power 403 and 408 is applied, it can be initiated after electrical power 403 and 408 is applied, or it can be initiated concurrently with the electrical power. The electrical power 403 and 408 across the graphite electrode assembly 404 and the graphite electrode bucket 406 will produce joule heating to the powder 407 that will keep the temperature in a target range with the help of an optional power controller. Flowing methane 401 gas through bucket reactor 406 will expose the gas to heat from powder 407 and will result in thermal decomposition of methane 401 into hydrogen 417 and solid carbon species 416 that may include: (a) solid carbon that deposits itself onto the carbon powder, (b) free solid carbon that is not deposited / attached to the carbon powder but stays trapped within the reactor, and (c) flowable solid carbon (fine dust) that is exhausted with the hydrogen, or any combination thereof. It is also expected that some methane may not decompose and will leave the reactor as unprocessed methane 415. The output hydrogen and carbon stream 424 can optionally be fed through a carbon separator and through a hydrogen separator system where hydrogen is separated from unwanted hydrocarbons or other residual gases and may be sent to a collection tank. The unprocessed methane 415 can optionally be sent back to mix with methane 401 for further reuse, or it can be collected separately.

[0087] Figures 5A-C illustrate another exemplary embodiment of the present invention that offers important variations. One difference between embodiments from Figure 5A-C and Figure 4 is the design of the electrode assembly. Figures 5B and 5C do not show all system components, including powder 507, gas tight electrical insulator lid 511, and other system components, for clarity of the illustration. The embodiment from Figures 5A-C has a rotating assembly 504 which may be made from 4 parts: a hollow graphite electrode top shaft 520, an oval hollow bottom graphite electrode 519, a gas inlet feedthrough 518, and electrically insulating powder stirring paddles 522. The shaft 520 and the bottom electrode 519 can be made from a single piece of graphite. The hollow center of shaft 520 and bottom electrode 519 also serve as the gas inlet feedthrough 518 for the injection of methane 501 inside conductive powder 507 located inside the bucket reactor 506. The stirring paddles 522 are a separate component made from electrically insulating material and are attached under the bottom electrode 519 while also having a center hole that allows methane gas to flow to the bottom of reactor 506. The embodiments of Figure 5A-C does not need an electrically insulating bottom 513 since the electrode part 519 is electrically isolated from the bottom of the graphite reactor 506 by the stirring paddles assembly 522. Insulating bottom 513 is therefore optional. One exemplary advantage of the embodiment described in Figure 5A-C is the ability to provide centralized methane 501 injection within reactor 506 with fewer parts. The top 520 and bottom 519 electrodes double as a feedthrough for gas flow. Another advantage is the presence of powder stirring paddles 522 that can have better reach and mixing of the powder 507 than the oval shaped electrode 404. The bottom end of electrode 404 (close to the bottom of the reactor) may also have other shapes, including for example round. In one example of the stirring paddles assembly 522, shown in Figure 5C, the assembly is constructed from a quartz disk with a center hole to allow gas flow and further comprises 4 angled paddles that can plow through powder 507 and make its mixing very uniform. Alternatively, the shape and size of the stirring paddles assembly electrode can be different than shown in Figure 5C as long as it functions to stir the powder 507. These exemplary advantages of electrode assembly 504 provide a more uniform heat profile that improves the efficiency of the methane pyrolysis process. Another variation the embodiment shown in Figure 5A-C, is that the oval hollow bottom electrode 519 can also bea cylindrical hollow bottom electrode, having the same diameter as the hollow electrode top shaft 520 or a different diameter. For a symmetric electrode shape, there is no need to provide electrode assembly rotation 509 which further simplifies the system.

[0088] The operation of the pyrolysis as disclosed in Figure 5A-C may be similar to the operation of the pyrolysis as disclosed in Figure 4. In the process of Figure 5A-C, air may be removed from graphite bucket 506 initially, or the vacuum pumping may continue throughout the pyrolysis process. The flow of methane gas 501 can be initiated before, after, or concurrently with when electrical power 503 and 508 is applied. The electrical power across the graphite electrodes assembly 504 and the graphite electrode bucket 506 will produce joule heating to powder 507 that will keep the temperature at a target range, optionally with the help of a power controller. Flowing methane 501 gas through bucket reactor 506 will expose the gas to heat from powder 507 and will result in thermal decomposition of methane 501 into hydrogen and solid carbon species. The output hydrogen and carbon stream 524 can optionally be fed through a carbon separator, and a hydrogen separator system, where hydrogen is separated from unwanted hydrocarbons or other residual gases and may be sent to a collection tank.

[0089] Figures 4 and 5A-C further disclose a batch process, where, after some number of cycles or after some process time, the total volume of all the carbons inside the reactor may increase due to the solid carbon formation from methane pyrolysis, which may require a periodical replacement of the powder within the reactor.

[0090] Figures 5D and E show an embodiment of the present invention in which the methane pyrolysis process may be done in a batch mode, in a continuous batch mode, or in a continuous mode of operation to increase the process throughput. It is understood that other embodiments of this process can be done in different modes, and using different steps in different order.

[0091] Continuous mode means that all process steps are conducted continuously without significant pauses between process steps. Continuous batch mode means that some process steps are conducted continuously, and some are done in sequence. In the continuous batch embodiment of Figures 5D and E, the methane pyrolysis is continuous until the conductivepowder needs replenishment. In the next step, the pyrolysis is paused and the powder can be replenished. In the next step, the methane pyrolysis can be continued. In the continuous embodiment of Figures 5D and E, the methane pyrolysis and the powder removal and filling may be done simultaneously in a continuous manner, without significant pauses between the pyrolysis process step and the powder replenishment process steps.

[0092] Figures 5D and 5E illustrate embodiments that offer important variations of the embodiment on the invention in Figures 5A-C. One difference between embodiments may be the replacement of the graphite bucket bottom of Figure 5A for a sliding gate bottom made from electrically isolating materials as shown in Figure 5D. The sliding gate bottom makes a gas tight seal with the reactor walls. Another difference may be the design of the powder stirring assembly. The stirring assembly in embodiments 5A-C has a solid disk base that is substantially covering the bottom of the reactor, and on which multiple (for example four) stirring paddles may be mounted. This design prevents any powder from reaching the bottom of the reactor. The embodiment of Figures 5D and 5E has a paddles base that only partially covers the bottom of the reactor (see exemplary paddles base 523, as shown in Figure 5E). Other shapes of the paddles base are possible as long as the paddles base does not obstruct the powder from reaching the bottom of the reactor, and the removable base does allow spent carbon to be removed from the bottom. The paddles base allows the conductive powder to reach the reactor bottom which is an electrically isolating sliding gate plate that can be moved away to let the spent powder fall off via gravity, and that can then be closed and refilled with new conductive powder.

[0093] Figure 5D discloses an embodiment which has a tube-like graphite reactor 510 with an open bottom. The new bottom is a sliding gate 530 made from electrically isolating materials. The embodiment further comprises a modified stirring assembly having slim stirring paddles base 523 that does not fully obstruct the reactor bottom, and that may have two or more stirring paddles 522. The modified stirring assembly may be attached to the electrode assembly 519 and 520 that can be rotated to mix the conductive powder. The electrode shape can be cylindrical or oval or rectangular or any other shape. The electrode assembly further comprises gas inlet feedthrough 518 that passes through the center of the electrode assembly.

[0094] The continuous batch operation of the pyrolysis with the system of Figures 5D-E, when using gas tight lid 511 (not shown in Figures 5E-D), can be to first close the sliding gate bottom 530, fill in conductive powder with powder feeder 525 that penetrates the lid 511, apply rotation to the electrode assembly 519 and 520 that penetrates lid 511, wherein the electrode also rotates stirring assembly 522 and 523 which mixes the conductive powder within the reactor, apply electrical power across the graphite electrodes 519 and 520 and the graphite tube reactor walls 510 to produce joule heating of the powder. Methane gas can be injected through the gas inlet feedthrough 518 that passes through the centerof the electrode assembly to inject methane gas near the bottom of the reactor and the sliding gate bottom 530. Hydrogen and carbon can be collected from the top of the reactor (if no lid is present) or from a gas outlet port penetrating lid 511 (if a lid is present). Once the conductive carbon is spent, the joule heating can be paused, the paddles can still be rotated to remove the powder more efficiently, the sliding gate bottom 530 can be slid away (moving the bottom laterally to the tube reactor while still maintaining contact with the tube bottom, until the bottom opens away and powder can be removed) to dump the spent carbon through a powder dispenser 529. After complete or partial powder disposal, the sliding gate bottom 530 can be slid back to cover the bottom of the tube reactor 510. New powder can be inserted via the powder feeder 525 to continue with the pyrolysis process. Methane flow can resume and joule heating can resume. Alternatively, in a continuous mode of operation the sliding gate bottom 530 may be opened and some spent carbon powder may be removed from the reactor, and new carbon powder may be fed into the reactor, while the methane pyrolysis is ongoing, allowing for continuous operation of the process.

[0095] Figure 6 illustrates Another exemplary embodiment of the present invention in which the methane pyrolysis process can be done in a continuous mode of operation to increase the process throughput. Continuous mode means that the joule heated pyrolysis, the used powder removal, and the fresh powder replenishment steps can be done concurrently in a continuous mode. With this embodiment, the methane pyrolysis and the generation of hydrogen is continuous and the pyrolysis does not need to stop or pause for replacement of the powder.

[0096] Figure 6 further illustrates an embodiment of this innovation that offers variations of the embodiments disclosed in Figures 4 and 5. One main difference to the embodiments ofFigures 4 and 5A-C is the inclusion of a continuous powder replenishment system and the modified design of the electrode assembly. The embodiment of Figure 6 includes a powder feeder 625 positioned on top of reactor 606 and mounted to the gas tight electrical insulator lid 611 by penetrating the lid. The embodiment of Figure 6 also includes a powder dispenser 629 positioned on bottom of reactor 606 by penetrating the reactor. Powder feeder 625 enables fresh (pre-process) electrically conductive powder 626 to be filled into the reactor body 606 and powder dispenser 629 enables used (post-process) electrically conductive powder 627 to be removed from reactor 606. Powder feeder 625 and powder dispenser 629 can be any shape that enables powder filling and removal. Powder feeder 625 and powder dispenser 629 can be synchronized with respect to each other so as to prevent agglomeration of powder 607 or depletion of powder inside reactor 606. Powder feeder 625 may include a screw or functionally similar mechanism that helps with the efficient pre-process powder 626 feeding. After the pre- process powder 626 exits the feeder 625, it may fall into reactor 606 with the help of gravity or via a suitable mechanism as known in the art. Stirring paddles assembly 622, which rotate 609 together with the electrode assembly 604, mix the pre-process powder 626 with powder 607 already present in reactor 606. Powder dispenser 629 may include a screw or functionally similar mechanism that helps with efficient post-process powder 627 dispensing from the reactor 606. In one mode of operation, the methane pyrolysis process is in continuous operation while the powder feeder 625 and powder dispenser 629 are operated intermittently to keep replenishing the powder 607 without interrupting the methane pyrolysis process.

[0097] The embodiment of Figure 6 may also include a modified design of electrode assembly 604. Graphite electrode assembly 604 may comprise a top graphite electrode segment having a round shape so as to accommodate rotation 609 of the electrode assembly with respect to fixed lid 611 and fixed reactor 606. The graphite electrode assembly 604 may also be stationary (not rotating) or intermittently rotating. The graphite electrode assembly 604 may further comprise a bottom graphite electrode segment having either round shape, oval shape, or any other shape that enables its function as an electrode with respect to the inner walls of the bucket reactor 606. The top electrode part and the bottom electrode part preferably may be made from a single piece of graphite. The graphite electrode assembly 604 further comprises ahollow core that goes from the top electrode and bottom electrode segments so as to allow methane gas 601 to flow from outside reactor 606 to inside reactor 606. Thus, the hollow center of the electrodes may serve as the gas inlet feedthrough for injection of methane 601 inside conductive powder 607 located inside bucket reactor 606. The graphite electrode assembly 604 may further comprise gas nozzles 618 positioned on the bottom of a graphite electrode segment so as to distribute methane gas 601 from the hollow core of the electrode to reactor 606 in a uniform manner. In one example, gas nozzles 618 may include more than one hole drilled perpendicular to the long axes of the bottom electrode, and an intersection with the hollow core of the electrode 604 in a manner that enables gas 601 to percolate the conductive powder 607. The graphite electrode assembly 604 may further include stirring paddles assembly 622 which may be made from electrically insulating materials and may be attached under the bottom electrode of the electrode assembly 604. In one embodiment of the stirring paddles assembly 622, the assembly may include a paddle shutter 621, an opening on the stirring paddles assembly 622 that allows powder 607 to be removed from reactor 606, but only when the paddle shutter 621 is aligned with dispenser opening 628 that allows post-process powder 627 to be removed from reactor 606. In one embodiment, the powder dispenser 629 may be positioned so as to penetrate the bottom of the bucket reactor 606, and also may penetrate the electrical insulator bottom 613, thus providing a flow path for the post-process powder 627 to be removed. Electrical insulator bottom 613 prevents electrical current flow to the bottom of reactor 606, and enables electrical current flow from electrode 604 toward the walls of graphite reactor 606. In Another exemplary embodiment, there may be no electrical insulator bottom 613, and electrode 604 may be electrically isolated from the bottom of reactor 606 by electrically insulating stirring paddles assembly 622. A paddle shutter opening 621 in the stirring assembly 622 may create a conductive path between the electrode 604 and the bottom of reactor 606, but with higher electrical resistance than the electrode to the wall of the reactor 606 electrical path, making joule heating possible.

[0098] The operation of the pyrolysis process from Figure 6 may be similar to the operation of the pyrolysis process from Figure 5. After the initial filling of electrically conductive powder 607, and initial air removal from the sealed graphite bucket reaction and electrode 606,enabled by sealing the top of the bucket 606 with a gas tight electrical insulator lid 611, the system is ready for operation. The vacuum pumping may continue through the continuous pyrolysis process. Continuous vacuum pumping may ensure that gas tight bucket lid 611 stays in firm contact with graphite bucket 606, and that hydrogen and carbon outlet stream 624 is being sucked through the outlet feedthrough more efficiently than through passive gas flow. The flow of methane gas 601 can be initiated before electrical power 603 and 608 is applied, it can be initiated after electrical power 603 and 608 is applied, or concurrently with the electrical power. The electrical power 603 and 608 across graphite electrodes assembly 604 and graphite electrode bucket 606 may produce joule heating to the powder 607 that will keep the temperature at a target range with the optional help of a power controller. Flowing methane 601 gas through bucket reactor 606 exposes the gas to heat from powder 607 and results in thermal decomposition of methane 601 into hydrogen and solid carbon species that may include: (a) solid carbon that deposits itself onto the carbon powder 607, (b) free solid carbon that is not deposited / attached to the carbon powder 607 but stays trapped within the reactor 606, and (c) flowable solid carbon (fine dust) that may be exhausted with the hydrogen. Some methane may not decompose and will leave the reactor as unprocessed methane. After enough solid carbon mass (deposited and free) is left inside reactor 606, powder 607 may become post-process powder 627 and may have to be removed to make space for fresh pre-process powder 626. The feeding of pre-process powder 626, and dispensing of post-process powder 627, may be done once every rotation 609 period, or once every set time period, for example once per hour, or it can be done as needed, while the pyrolysis process can be done continuously, independent from the powder replenishment schedule and timing. In one embody, electrical power 603 and 608 may be synchronized with the electrode assembly rotation 609, so that when paddle shutter 621 is aligned with dispenser opening 628 and power dispenser 629, the electrical power is paused so as to avoid passing currents trough the post-process powder 627 and dispenser 629.

[0099] Output hydrogen and carbon stream 624 can optionally be fed through a carbon separator and / or through a hydrogen separator system where hydrogen is separated from unwanted hydrocarbons or other residual gases and may be sent to a collection tank. Theunprocessed methane can optionally be sent back to mix with methane 601 for further reuse or it can be collected separately.

[0100] Figure 7 shows one embodiment of a continuous process system for continuous electrical methane pyrolysis with the ability to continuously replenish the powder as illustrated in the embodiment described in regard to Figure 6. Figures 7A and 7B do not show the conductive powder, the full electrode assembly system, or certain other system components for clarity of the illustration. Figure 7 shows that hollow graphite electrode bottom 704 and stirring paddles assembly 722, which may be attached to the bottom side of the hollow graphite electrode bottom 704, are positioned concentrically with the graphite reactor walls and with electrode 706. Electrode 704 and stirring paddles assembly 722 may be configured to rotate with respect to bucket reactor 706. The graphite electrode may comprise a top graphite electrode segment (not shown) and bottom graphite electrode segment 704 which may be round shape, oval shape, or any other suitable shape as known in the art that enables its function as an electrode with respect to the inner walls of bucket reactor 706. The hollow center of the top and bottom 704 electrode segments may serve as gas inlet feedthrough 718 for injection of methane into the conductive powder located inside bucket reactor.

[0101] Stirring paddles assembly 722 may be made from electrically insulating materials. Stirring paddles assembly 722 may comprise 4 angled paddles 723 that can plow (or mix or move) through the conductive powder and mix the powder during the electrical pyrolysis process, and produce a substantially uniformly heated powder bed which will promote uniform pyrolysis of the methane. Alternatively, the number, shape, and size of stirring paddles 722 may be different than shown in Figure 7, as long as it functions to stir the conductive powder. Stirring paddles assembly 722 further comprises at least one paddle shutter 721. In one example, paddle shutter 721 is a single hole on stirring paddles assembly 722 as shown in Figure 7. Alternatively, paddle shutter 721 can have different shapes and sizes, including for example, a slit or a wedge opening.

[0102] The system of Figure 7 may further comprise a dispenser opening 728, comprising a hole on electrical insulator bottom 713 aligned to a hole on the bottom of bucket reactor 706. Dispenser opening 728 may be connected to the powder dispenser (not shown) to provide a mechanical path for post-process powder to be removed from reactor 706. Electrical insulatorbottom 713 prevents electrical current flow to the bottom of reactor 706, and enables electrical current flow from electrode 704 toward the walls of graphite reactor 706.

[0103] Figure 7A shows the rotational position of the stirring paddles assembly 722 with respect to the bottom of the bucket reactor 706, in which paddle shutter 721 is not aligned with dispenser opening 728 and thus post-processed powder cannot be dispensed from reactor 706. At one rotational position, shown in Figure 7B, the stirring paddles assembly 722, and in particular the paddle shutter 721, is aligned with dispenser opening 728 to enable post-processed powder to be transported (dispensed) from reactor 706. In some examples of operation, stirring paddle assembly 722 rotation is not uniform, and the paddle assembly spends more time in rotational position of Figure 7A (no powderflow) than rotation position Figure 7B (powder flow). In another example, the stirring paddle assembly 722 rotation is uniform until it reaches the rotational position of Figure 7B (powder flow), and dwells there to allow post-process powder to be removed. In yet another example, the stirring paddle assembly 722 rotation is uniform. These are only some examples and it is understood that the stirring paddles can operate in different ways to a similar effect.

[0104] Figure 8 illustrates another embodiment that may offer variations of the embodiments described in regard to Figures 5 and 6. One difference between the embodiment in Figure 8 to the embodiments in Figure 5 and Figure 6 may be the modification of the stirring paddles and of the electrode assemblies. Although Figure 8 illustrates a batch process system, the system components from Figure 6 that make the process continuous can easily be integrated in the system of Figure 8. Figure 8 does not show the conductive powder nor certain other system components for clarity of the illustration.

[0105] The embodiment from Figure 8 may have stirring paddles assembly 822 separate and independent from graphite electrode assembly 804. Stirring paddles assembly 822 may comprise of stirring paddles 823, stirring paddles base 826, and stirring paddles shaft 825. The stirring paddles assembly 822 may be positioned at the bottom of graphite reactor 806, separately from graphite electrode assembly 804, and may be connected to a drive mechanism (not shown) located at the bottom of graphite reactor 806 by a shaft 825 that penetrates an optional electrical insulator bottom 813 and the bottom of the graphite reactor 806. In theembodiment from Figure 8, the stirring paddles assembly 822 may be rotated 824 with respect to stationary graphite reactor 806 to stir the conductive powder to produce a more uniform heat distribution of the powder. Stirring paddles assembly 822 may be made from electrically insulating materials such as quartz or ceramic, or metal materials coated with insulating material coating. In some embodiments, shaft 825 may be made from electrically insulating materials, but base 826 and stirring paddles 823 may be made from graphite or metal. In other embodiments, shaft 825 and base 826 may be made from electrically insulating materials but stirring paddles 823 may be made from graphite or metal. In still other embodiments, shaft 825 and stirring paddles 823 may be made from electrically insulating materials but base 826 may be made from graphite or metal. Other combinations that use combination of electrically insulating materials and electrically conducting materials, but prevent the electrical current from flowing from stirring paddles assembly 822 to the shaft drive mechanism are also possible. Stirring paddles assembly 822 that is rotated 824 by an external drive mechanism (not shown), may comprise 4 angled paddles 823 that can plow (or mix or move) through the conductive powder and mix the powder during the electrical pyrolysis process, and produce a uniformly heated powder bed which will promote uniform pyrolysis of methane. Alternatively, the number, shape, and size of stirring paddles 822 may be different than shown in Figure 8, as long as it functions to stir the conductive powder.

[0106] The embodiment of Figure 8 may also include a modified design of electrode assembly 804. Graphite electrode assembly 804 may comprise a top graphite electrode segment having a round shape so as to accommodate optional rotation 809 of the electrode assembly with respect to the stationary bucket reactor lid (not shown). Graphite electrode assembly 804 may further comprise round hollow bottom graphite electrode segment 819 that may not have to be rotated because stirring paddles assembly 822 may move the conductive powder around the stationary graphite electrode assembly 804, thus enabling uniform joule heating of the powder. Eliminating electrode rotation may make the embodiment from Figure 8 simpler to operate. Additionally, the current density field between round electrode 819 and round bucket 806 may be symmetrical (as disclosed with embodiment of Figure 4), thus eliminating the need to rotate the electrode. Alternatively, bottom graphite electrode segment 819 may have an ovalshape, or any other complex shape known in the art, for producing a focused current density field between an oval electrode and round bucket (as disclosed with embodiment of Figure 4). However, the oval graphite electrode segment may not have to be rotated because the stirring paddles assembly 822 may move the conductive powder around the stationary oval graphite electrode assembly, thus enabling uniform joule heating of the powder. Optionally, a round or oval electrode of the embodiment shown in Figure 8 may be rotated. Graphite electrode assembly 804 may include a hollow center that may serve as gas inlet feedthrough 818 for injection of methane from the gas feeder, and may include at least one nozzle 817 that may distribute the methane gas within the volume of the conductive powder located inside bucket reactor 806.

[0107] Figure 9 illustrates additional modifications of the embodiment described in regard to in Figure 8. One difference between the embodiment in Figure 9 to the embodiments described in regard to Figure 8 is the modification of the electrode assembly. Although Figure 9 illustrates a batch process system, the system components from Figure 6 that make the process continuous may easily be integrated into the system of Figure 9. Figure 9 does not show the conductive powder nor certain other system components for clarity of the illustration.

[0108] The embodiment of Figure 9 may include a modified design of electrode assembly 904 and 905 that are independent from stirring paddles assembly 922, meaning that electrode assembly 904 and 905 may be independently rotated (or not rotated) from the stirring paddles assembly 922 and vice versa. The embodiment of Figure 9A shows independent offset round electrode assembly 904, while Figure 9B shows independent offset oval electrode assembly 905.

[0109] The independent graphite electrode assembly 904 and 905 does not have to be rotated because independent stirring paddles assembly 922 may move the conductive powder around the stationary graphite electrode assembly 904 and 905, thus enabling uniform joule heating of the powder. One advantage of offset (off-center) round 904 electrode is that with the offset electrode shape, the electrical current may be more focused in the direction of the offset, thus providing current density that is higher than with a centered round electrode. Higher current density may mean that the system may be operated at lower electrical current to achieve pyrolysis temperatures.

[0110] One advantage of offset (off-center) oval electrode 905 is that with the offset electrode shape the electrical current may be more focused in the direction of the long axis of the oval electrode, and additionally more focused in the direction of the offset, thus providing current density that is higher than with the centered oval electrode. Higher current density may mean that the system may be operated at lower electrical current to achieve pyrolysis temperatures.

[0111] Figure 10 shows another embodiment in which the methane pyrolysis process can be done in a batch mode (Figure 10A), or in a continuous batch mode (Figure 10B) of operation to increase the process throughput. Continuous batch mode means that some process steps are conducted continuously, and some are done in sequence. In the embodiment of Figure 10B, the methane pyrolysis is continuous until the conductive powder needs replenishment. In the next step, the pyrolysis is paused and the powder is replenished. In the next step, the methane pyrolysis is continued.

[0112] It may be desirable to have a joule heating design using a bucket reactor where the shortest path for the current to flow is from the electrode sidewalls to the bucket sidewalls to minimize localized hot spots and to expose much of the conductive powder to joule heating. If the shortest current path is between the electrode and the bucket bottom, then the majority of the current can go through this path, thus localizing the joule heating and potentially overheating the reactor bottom. In an embodiment described in regard to Figure 4, electrodebucket isolation may be achieved by inserting an electrically insulating bottom that substantially covered the bucket reactor bottom wherein the powder mixing was done by rotating the oval electrode. In an embodiment described in regard to Figures 5A and 5B, the electrode-bucket isolation may be achieved by inserting an electrically insulating stirring paddles assembly that substantially covered the bucket reactor bottom and also mixed the powder. In an embodiment described in regard to Figure 5D, the electrode-bucket isolation may be achieved by inserting removable electrically insulating bottom that may replace the electrically conductive bucket reactor bottom, wherein the removable bottom may also be utilized to remove the spent powder. In the embodiment described in regard to Figures 6 and 7, electrode-bucket isolation may be achieved by inserting an electrically insulating stirring paddles assembly and anelectrically insulating bottom where the paddles and the bottom can align to enable powder removal. In an embodiment described in regard to Figures 8 and 9, electrode-bucket isolation may be achieved by inserting an electrically insulating stirring paddles assembly that may be operated from the bottom of the reactor and may be independent from the electrode.

[0113] In the described single electrode designs, having an exposed electrode bottom in a conductive graphite bucket reactor may generate nonuniform biased current flow from the bottom of the electrode to the bottom of the bucket, creating a nonuniform heating profile in the bucket reactor. Having a rounded bottom end of the electrode (close to the bottom of the reactor) may improve the nonuniform current flow towards the bottom of the bucket. A better more uniform heating profile in the bucket reactor is achieved when the current flow is forced from the electrode towards the bucket reactor walls (the counter electrode).

[0114] Figure 10 illustrates embodiments of the present invention where the electrodebucket isolation is achieved by capping the bottom end of the electrode 1019 with an electrically insulating cup 1022. The electrically insulating cup can be made out of ceramic (or other insulating heat resistant) material, and can be optimized to cover the bottom portion of the electrode at least to a height that substantially directs current flow to the side walls of the reactor instead of the bottom. For example, the bottom 1 - 5% of the electrode tip could be covered by the cup to achieve this goal. The electrode cup may be implemented via a suitable insulating coating or any other method of insulation known in the art. This design allows the electrode to have full XYZ0 motion range 1018 while forcing the electrical current away from the reactor bottom and towards the reactor walls 1006 and 1010. The conductive powder 107 mixing is achieved by moving the electrode 1019 in XYZ space as well as having the capability to rotate the electrode in 0 space. The Figure 10 embodiments have a hollow electrode 1019 that double as gas feedthrough 1018 to inject methane gas near the bottom of the reactor 1006, 1010. The Figure 10B embodiment additionally has a sliding gate bottom that can be electrically insulating or electrically conducting and allows the spent powder to be easily removed from the reactor. The Figure 10 embodiments do not show gas tight electrical insulator lid and other system components for clarity of the illustration. Other system components comprising with the embodiments of Figure 10 are gas outlet port (not shown), power feeder 1025, and powerdispenser (Figure 1029 only). The Figure 10 embodiments can be used with and without a lid. In the absence of a lid, the function of the gas outlet port may be performed by an exhaust vent or any other conventional methods to capture gas. The Figure 10 embodiments can be used for gas pyrolysis and for general joule heating of a powder, including converting joule heated powder to another state of matter.

[0115] The embodiments of this innovation describe methods and systems for thermal decomposition of methane, hydrocarbons, organic compound gas, and other gases in general. However, the disclosed methods and systems also apply to a general method for thermally activated chemical reaction of a gas with a reactant powder that has an affinity for a chemical reaction with the gas at high temperatures, wherein reactant powder is combined (mixed) with an electrically conductive powder, and wherein the gas flows through a joule heated volume of the conductive and reactant powders. In one alternative embodiment, the thermally activated chemical reaction is chlorination of metal oxides and other metal compounds into metal chlorides, wherein the gas is chlorine, and the reactants comprise metal oxides or compounds that are combined (mixed) with the conductive powder. The chlorination process is commonly used in metallurgy for metal extraction from ores. The chlorination of the prior art may be conducted using fluidized bed reactors with indirect heat transfer from the heating elements to the metal oxides at exemplary temperatures ranging from 900 to 1300 C under the influence of chlorine gas. In one example, the ore is lithium containing ore that is mixed with a conductive carbon power like for example PetCoke, the gas may be chlorine, and the process temperature may be between 1300 to 1800 C. The resulting lithium chloride can be recovered as a coating deposited on the carbon powder grains that can be rinsed with water. Alternatively, gaseous lithium chloride can be collected from the gas outlet feedthrough and then condensed as solid lithium chloride in a cold trap. Rinsing the cold trap with water will recover the solid lithium chloride.

[0116] In one alternative embodiment of the invention, the thermally activated chemical reaction may be reduction of oxides with hydrogen gas, wherein reactant oxides are combined (mixed) with the conductive powder. In one example, the chemical reaction may be reduction of silicon dioxide into silicon, wherein the gas is hydrogen, and wherein the reactant silicondioxide is mixed with the conductive powder. In yet another example, there may be more than one chemical reaction of gases, wherein the first reaction is methane pyrolysis into hydrogen and carbon, and the second reaction is reduction of iron oxide into iron, with hydrogen from the methane pyrolysis. The reactant iron oxide powder is mixed with the conductive powder before heating the combined powder.

[0117] While the above description provides examples of various apparatuses, methods, and systems, other apparatuses, methods, or systems may be within the reasonable scope of the claims as interpreted by one of skill in the art.

Claims

I CLAIM:

1. A method for thermal decomposition of methane gas, comprising infusing the methane gas within a volume of gas permeable electrically conductive powder and heating the conductive power by joule heating in a reactor to cause the thermal decomposition.

2. The method of Claim 1, wherein the powder is carbon powder.

3. The method of Claim 1, wherein the reactor is sealed.

4. The method of Claim 1, wherein the powder is first heated, and the methane is then infused.

5. The method of Claim 1, wherein the methane is first infused and then the powder is heated.

6. The method of Claim 1, wherein the methane flow is static.

7. The method of Claim 1, wherein the methane flow is continuous.

8. The method of Claim 1, wherein the methane flow is intermittent.

9. The method of Claim 1, wherein infusion comprises methane flowing partially through the volume of the joule heated powder and partially outside the powder volume.

10. The method of Claim 1, wherein infusion comprises methane flowing outside the volume of the joule heated powder.

11. The method of Claim 1, wherein the applied voltage used for joule heating is AC, DC, modified AC or DC, or any combination thereof.

12. The method of Claim 2, wherein the carbon powder is joule heated by applying a voltage between 120 V and 480 V to the powder.

13. The method of Claim 2, wherein the surface area of the carbon powder is between 1 and 100 m2 / g.

14. The method of Claim 2, wherein the bulk electrical resistance of the carbon powder is between 1 to 1000 Ohms.

15. The method of Claim 1, wherein the heat transfers from the joule heated powder via radiation, conduction, or a combination thereof, to the methane gas.

16. The method of Claim 2, wherein the carbon includes at least one of amorphous carbon, graphitized carbon, crystalline carbon, graphene, turbostratic graphene, graphite, turbostratic graphite, AB stacked graphite, ABC stacked graphite, carbon nanotubes, and nanofibers.

17. The method of Claim 2, wherein the carbon includes at least one of solid carbon that deposits itself onto the carbon powder, free sold carbon that is settled within the carbon powder, and flowable sold carbon (fine dust or fines) that is exhausted with the hydrogen.

18. The method of Claim 2, wherein the carbon powder includes at least one of: calcinated petroleum coke, metallurgical coke, carbon black, activated carbon, char, graphene, flash graphene, carbon nanotubes, carbon nanofibers, carbon fiber, graphitized carbon fiber.

19. The method of Claim 2, wherein the carbon powder includes at least one of: anthracite coal, green petroleum coke, asphaltenes, recycled-tire carbon black, bio char, wood char, plant char, paralyzed cellulose, conductive polymer, conductive plastic, plastic char, plastic ash.

20. The method of Claim 2, wherein the carbon powder morphologies include: powder, grain, pellets, chunks, sphere-like, hollow sphere-like, particles, spheres, nanospheres, microspheres, rods, nanotubes, nanowires, and microwires, microfibers, matrix-forming structures, and any combination thereof.

21. The method of Claim 2, wherein the carbon powder material structures include: non-porous, porous, nanoporous, microporous, and layered structures, and any combination thereof.

22. The method of Claim 2, wherein the carbon powder has a size between 30 nm to 1 micron.

23. The method of Claim 2, wherein the carbon powder has a size between 1 microns to 5 mm.

24. The method of Claim 2, wherein the carbon powder crystallinity is not substantially changed.

25. The method of Claim 2, wherein the carbon powder crystallinity is substantially changed.

26. The method of Claim 16, wherein the carbon powder is converted to graphite, turbostratic graphite, graphene, turbostratic graphene, polyhedral graphite, polyhedral graphene, turbostratic polyhedral graphite, turbostratic polyhedral graphene, carbon nanotubes or nanofibers, graphitized fibers, or any combination thereof.

27. The method of Claim 2, wherein the carbon powder includes at least one non-conductive filler such as high density polyethylene, low density polyethylene, polypropylene, polystyrene, Styrofoam, polyethylene terephthalate (PET), polyacrylonitrile (PAN), plastics, waste plastics, cellulose, sugar, paraffins, urea, or any combination thereof.

28. The method of Claim 1 , wherein the non-conductive filler material is thermally decomposed by the heat from the joule heated carbon powder to produce hydrogen and carbon formations.

29. The method of Claim 28, wherein the carbon formations include graphite, graphene, nanotubes, nanofibers, or any combination thereof.

30. The method of Claim 28, wherein the carbon formations form at least one carbon composite with the carbons from the methane decomposition.

31. The method of Claim 30, wherein carbon composites include at least one of graphite, graphene, or nanotubes from the methane and graphite, graphene, or nanotubes from at least one decomposed non-conductive filler.

32. The method of Claim 2, wherein the carbon powder includes at least one metal-based catalyst to modify the methane decomposition to include formation of carbon with high aspect ratios (nanotube and nanofiber).

33. The method of Claim 32, wherein the carbon with high aspect ratios form at least one composite with 3D carbon fractions from the methane decomposition.

34. The method of Claim 32, wherein the metal-based catalyst includes at least one of: Fe, Co, Ni, Cu, other transition metals, iron acetate, iron chloride, metal chlorides, chlorides, iron acetylacetonate, iron oxide, cobalt oxide, other transition metal oxide, iron hydroxide, nickel hydroxide, other transition metal hydroxide, or a combination thereof.

35. The method of Claim 2, wherein the carbon powder includes at least one silicon-based additive to enable synthesis of silicon-based composites that are covered with or decorated with the carbon from the methane decomposition.

36. The method of Claim 35, wherein the silicon-based additive comprises at least one of silicon, silicon dioxide, silicon oxide (SiOx), silicon carbide, or their combination in the morphological form of nanospheres, microspheres, nanotubes, nanowires as well as any combination thereof.

37. The method of Claim 35, wherein the silicon-based composite is a silicon carbide.

38. The method of Claim 35, wherein the silicon-based composite is a silicon particle wrapped in graphene layers.

39. The method of Claim 2, wherein the temperature of the joule heated powder is between 700 to 1300 C during the thermal decomposition.

40. The method of Claim 2, wherein the electrical power of the joule heating is automatically adjusted to achieve a desired thermal decomposition temperature.

41. The method of Claim 2, wherein the electrical power of the joule heating is automatically adjusted to achieve desired gas parameters, including at least one of gas purity, yield, or pressure.

42. The method of Claim 1, wherein the reactor is a horizontally or vertically oriented quartz tube reactor.

43. The method of Claim 1, wherein the method comprises filling a tube reactor with electrically conductive powder, sealing the reactor ends with two graphite electrodes, purging the reactor with inert gas to remove moisture and air, applying electrical power across the two graphiteelectrodes from opposing sides of the powder that results in joule heating the powder, flowing methane gas through the joule heated powder that will result in thermal decomposition of the methane into hydrogen and carbon fractions, collecting the hydrogen and carbon fractions that flow out from the reactor, filtering the carbon fractions from the hydrogen with a carbon separator, and filtering the hydrogen from other hydrocarbons or other residual gases, and storing the hydrogen in a holding tank.

44. A method for thermal decomposition of methane inside a sealed reactor wherein the methane decomposes into at least hydrogen and carbon as it flows through a volume of joule heated carbon-based powder.

45. The method of Claim 44, wherein the reactor is a horizontal tube reactor.

46. The method of Claim 44, wherein the thermal decomposition system further comprises at least one of: gas feeder, carbon separator, hydrogen separator, and an unprocessed methane return line.

47. The method of Claim 46, wherein hydrogen or carbon or both are continuously removed from the reactor.

48. The method of Claim 47, wherein the removed carbon is filtered from the hydrogen with a carbon separator.

49. The method of Claim 48, wherein the removed carbon includes at least one of carbon black, graphite, graphene, nanotubes, nanofibers, carbon composites, and any combination thereof.

50. The method of Claim 48, wherein the removed hydrogen is filtered from the residual methane with a hydrogen separator.

51. The method of Claim 50, wherein the residual methane is returned back to the gas feeder.

52. The method of Claim 43, wherein the carbon-based powder is periodically replaced.

53. The method of Claim 52, wherein the replaced carbon based powder is filtered, and the filtrate comprises at least one of carbon black, graphite, graphene, nanotubes, nanofibers, and carbon composites.

54. The method of Claim 43, wherein the reactor is a vertical tube reactor with conical ends.

55. The method of Claim 43, wherein the method is a continuous batch operation that includes the steps of moving the electrodes away from the reactor, removing the spent carbon powder, filling in new carbon powder, inserting the electrodes into the reactor, and continuing with the thermal decomposition of methane.

56. The method of Claim 55, wherein the removed carbon comprises at least one of carbon black, graphite, graphene, nanotubes, nanofibers, and carbon composites.

57. A method for thermal decomposition of methane inside a sealed reactor wherein the methane decomposes into at least hydrogen and carbon as it flows through a volume of joule heated carbon-based powder while the powder is being mixed.

58. The method of Claim 57, wherein the method includes the steps of: inserting powder into a bucket reactor, closing a gas tight lid, mixing the powder while applying electrical power to the powder to joule heat the powder, flowing methane near the bottom of the bucket reactor, collecting hydrogen or carbon or both near the top of the bucket reactor, removing the lid, and removing some or all of the spent carbon powder.

59. The method of Claim 58, wherein hydrogen or carbon or both are continuously removed from the reactor.

60. The method of Claim 59, wherein carbon is filtered from the hydrogen with a carbon separator, wherein carbon comprises at least one of: carbon black, graphite, graphene, nanotubes, nanofibers, carbon composites, or any combination thereof.

61. The method of Claim 58, wherein at least one of carbon black, graphite, graphene, nanotubes, nanofibers, and carbon composites is filtered from the spent powder.

62. The method of Claim 57, wherein the method includes the steps of: inserting powder into a bucket reactor, mixing the powder while applying electrical power to the powder to joule heat the powder, flowing methane near the bottom of the bucket reactor, collecting hydrogen or carbon or both from the top of the bucket reactor, and removing at least some of the spent carbon powder.

63. The method of Claim 57, wherein hydrogen or carbon or both are collected from an outlet port penetrating a gas tight lid of a bucket reactor64. The method of Claim 57, wherein the powder is mixed with a rotating stirring paddle assembly.

65. The method of Claim 57, wherein the method includes the steps of: closing the removable reactor bottom, inserting powder into a bucket reactor, mixing the powder while applying electrical power to the powder to joule heat the powder, flowing methane near the bottom of the bucket reactor, collecting hydrogen or carbon or both from the top of the bucket reactor, opening the removable reactor bottom, removing spent carbon powder through the reactor bottom, and repeating the cycle.

66. The method of Claim 65, wherein the process is continuous.

67. The method of Claim 66, wherein the process is a continuous batch process.

68. The method of Claim 57, wherein the method includes the steps of: inserting powder into a bucket reactor through a feeder near the top of the reactor, mixing the powder while applying electrical power to the powder to joule heat the powder, flowing methane inside the bucket reactor, collecting hydrogen or carbon or both near the top of the bucket reactor, dispensing powder from the reactor through a dispenser at the bottom of the reactor, and repeating the cycle.

69. The method of Claim 68, wherein the process is continuous.

70. The method of Claim 57, further comprising inserting powder into a reactor, mixing the powder with a cupped electrode while applying electrical power to the powder to joule heat the powder, flowing methane near the bottom of the bucket reactor, collecting hydrogen or carbon or both from the top of the bucket reactor.

71. The method of Claim 70, wherein the spent carbon powder is removed by opening a removable bottom.

72. A method of joule heating a powder, comprising joule heating an electrically conductive powder in a vacuum inside a bucket reactor.

73. The method of claim 72, further comprising mixing the powder during the joule heating.

74. The method of claim 72, further comprising removing spend powder using a removable bottom.

75. A system for thermal decomposition of gas comprising: a reactor capable of containing a volume of electrically conductive powder; a mechanism for flowing gases through said powder; and electrodes for joule heating said powder.

76. The system of Claim 75, wherein the reactor is sealed from the atmosphere.

77. The system of Claim 75, where the reactor is capable of operating with non-compressed conductive powder.

78. The system of Claim 75, where the reactor is capable of operating with compressed conductive powder.

79. The system of Claim 76, wherein the system further comprises: a tube reactor for holding a carbon-based powder that can at least partially fill the tube reactor;graphite electrodes at each end of the tube reactor, wherein the electrodes can supply electrical power to the powder to joule heat the powder; a gas inlet feedthrough, wherein at least one gas can be injected into the reactor; a gas outlet feedthrough, wherein at least one decomposed gas can be removed from the reactor.

80. The system of Claim 79, wherein the system further comprises at least one of: a gas feeder, a carbon separator, a hydrogen separator, or an unprocessed methane return line.

81. The system of Claim 76, wherein the system further comprises: a tube reactor having conical ends; graphite electrodes at each end of the tube reactor, wherein the electrodes can supply electrical power to the powder to joule heat the powder; a gas inlet feedthrough, wherein at least one gas can be injected into the reactor; a gas outlet feedthrough, wherein at least one decomposed gas can be removed from the reactor; and a mechanical assembly that moves the electrodes away from the reactor, removes the spent carbon powder, fills in new carbon powder, and inserts the electrodes into the reactor.

81. The system of Claim 78, wherein the tube reactor is vertical or tilted.

82. The system of Claim 74, wherein the system further comprises: an electrically conductive bucket reactor for holding electrically conductive powder having an electrically insulating bottom and a removable gas tight lid that is electrically insulated from the bucket; a stationary electrically conductive electrode assembly inside the bucket, wherein the electrode is electrically insulated from the bucket and the lid, wherein the electrode penetrates the lid to make electrical contact with a power source, andwherein the electrode is electrically connected to the conductive powder wherein electrical power can be applied between the electrode and the walls of the bucket to joule heat the powder; a gas inlet feedthrough near the bottom of the reactor; and a gas outlet feedthrough near the top of the reactor.

83. The system of Claim 82, wherein at least one gas feedthrough penetrates the lid.

84. The system of Claim 83, wherein the gas inlet and outlet feedthroughs are positioned on opposing sides of the lid.

85. The system of Claim 82, wherein at least one gas feedthrough penetrates the bucket.

86. The system of Claim 85, wherein the gas inlet and outlet feedthroughs are positioned on opposing sides of the bucket.

87. The system of Claim 82, wherein the electrode can be rotated to mix the powder.

88. The system of Claim 87, wherein the electrode rotation can be a rotational rocking motion.

89. The system of Claim 82, wherein the electrode has an oval shaped portion for mixing the powder, and a shaft portion that penetrates the gas tight lid and allows for rotation of the electrode.

90. The system of Claim 82, wherein the stationary electrode assembly is positioned near the center of the lid.

91. The system of Claim 90, further comprising a brush connector or a spring loaded rolling bearings connector electrically connected to the rotating electrode.

92. The system of Claim 82, wherein the system further comprises: a graphite bucket reactor for holding a conductive powder, having ceramic bottom;a gas tight lid that is electrically insulated from the bucket; a stationary rotating electrode inserted into the bucket that can mix the powder, wherein electrical power can be applied between the electrode and the graphite bucket to joule heat the powder; a gas inlet near the bottom of the reactor; and a gas outlet near the top of the reactor.

93. The system of Claim 85, wherein the system further comprises: a graphite bucket reactor for holding a conductive powder, having a ceramic bottom; a gas tight lid that can slide over the bucket and that is electrically insulated from the bucket; a moving electrode inserted into the bucket that can mix the powder, wherein electrical power can be applied between the electrode and the graphite bucket to joule heat the powder; a gas inlet port near the bottom of the reactor; and a gas outlet port near the top of the reactor.

94. The system of Claim 84, wherein the system further comprises: an electrically conductive bucket reactor for holding electrically conductive powder; a rotating assembly inside the bucket comprising an electrically insulating powder-stirring paddle assembly substantially covering the reactor bottom; having a center hole and a hollow graphite electrode; wherein the hollow electrode and the stirring paddle assembly align to enable gas injection near the bottom of the reactor, wherein the graphite electrode is centered onto the stirring paddle assembly and is electrically insulated from the bucket bottom, wherein the electrode can be electrically connected to the conductive powder,wherein electrical power can applied between the electrode and the walls of the bucket to joule heat the powder.

95. The system of Claim 94, wherein the bucket has a gas tight lid that is electrically insulated from the bucket.

96. The system of Claim 95, wherein the electrode penetrates the lid to make electrical contact.

97. The system of Claim 94, wherein the electrode is oval shaped.

98. The system of Claim 95, wherein the lid includes a gas outlet port.

99. The system of Claim 94, wherein the powder stirring paddle assembly comprises multiple stirring paddles located near the bucket walls.

100. The system of Claim 94, wherein the powder stirring paddle assembly comprises a disk part and multiple paddles, wherein the multiple paddles are substantially perpendicular to the disk part.

101. The system of Claim 75, wherein the system further comprises: an electrically conductive tube reactor for holding electrically conductive powder, the reactor having electrically isolating sliding gate bottom; a rotating assembly inside the bucket comprising an electrically insulating powder-stirring paddle assembly partially covering the reactor bottom, having a center hole and a hollow graphite electrode, wherein the hollow electrode and the stirring paddle assembly align to enable gas injection near the bottom of the reactor, wherein the graphite electrode is centered onto the stirring paddle assembly, wherein the electrode can be electrically connected to the conductive powder, wherein electrical power can be applied between the electrode and the walls of the reactor to joule heat the powder, andwherein the sliding gate bottom may be opened to remove spent powder.

102. The system of Claim 101, further comprising a powder feeder and a powder dispenser.

103. The system of Claim 101, wherein system can be operated either in continuous mode or in continuous batch mode.

104. The system of Claim 101, wherein the reactor has a gas tight lid that is electrically insulated from the bucket.

105. The system of Claim 104, wherein the lid includes a gas outlet port.

106. The system of Claim 75, wherein the system further comprises: a graphite tube reactor for holding conductive powder, having a removable ceramic bottom, a rotating electrode, a rotating ceramic paddle partially covering the reactor bottom, wherein the electrode and paddle are connected and inserted into the bucket to mix the powder, wherein electrical power can be applied between the electrode and the graphite reactor to joule heat the powder.

107. The system of Claim 106, further comprising a powder feeder and a powder dispenser.

108. The system of Claim 106, wherein the system can be operated in a continuous mode.

109. The system of Claim 75, wherein the system further comprises: an electrically conductive bucket reactor for holding electrically conductive powder, having an opening at the reactor bottom, a gas tight lid that is electrically insulated from the bucket, a rotating assembly inside the bucket comprising of an electrically insulating powder-stirring paddle assembly substantially covering the reactor bottom, having an opening that aligns with the reactor opening once per revolution, a hollow graphite electrodewherein the graphite electrode enables gas injection inside the bucket, wherein the graphite electrode is centered onto the stirring paddle assembly and is electrically insulated from the bucket bottom, wherein the graphite electrode can be electrically connected to the conductive powder, wherein electrical power can be applied between the electrode and the walls of the bucket to joule heat the powder; and a gas outlet feedthrough near the top of the reactor.

110. The system of Claim 109, wherein the system further comprises: a powder feeder penetrating the lid, a powder dispenser positioned on the bottom of the reactor, wherein the dispenser is aligned with the opening at the reactor bottom.

111. The system of Claim 110, wherein the system can be operated in a continuous mode.

112. The system of Claim 75, wherein the system further comprises: an electrically conductive bucket reactor for holding electrically conductive powder; a rotating electrically insulating powder-stirring paddle assembly substantially covering the reactor bottom, wherein the paddle penetrates the bottom of the reactor with an extension shaft, and wherein the shaft and the paddles may be rotated from outside the reactor, a hollow graphite electrode, wherein the hollow electrode enables gas injection near the bottom of the reactor, wherein the graphite electrode is electrically insulated from the bucket bottom, wherein the electrode is electrically connected to the conductive powder, wherein electrical power can be applied between the electrode and the walls of the bucket to joule heat the powder.

113. The system of Claim 112, wherein the bucket has a gas tight lid that is electrically insulated from the bucket.

114. The system of Claim 112, wherein the electrode penetrates the lid to make electrical contact.

115. The system of Claim 112, wherein the electrode is cylinder shaped and centered within the reactor.

116. The system of Claim 112, wherein the electrode is cylinder shaped and positioned off-center with respect to the reactor.

117. The system of Claim 112, wherein the electrode is oval shaped and positioned off-center with respect to the reactor.

118. The system of Claim 112, wherein the lid includes a gas outlet port.

119. The system of Claim 75, wherein the system further comprises: an electrically conductive reactor for holding electrically conductive powder, a hollow graphite electrode, having an electrically insulating cup at the end inserted into the reactor, wherein the graphite electrode is electrically insulated from the bucket bottom by the cup, wherein the graphite electrode can move within the reactor, wherein the hollow electrode enables gas injection near the bottom of the reactor, wherein the electrode is electrically connected to the conductive powder, wherein electrical power can be applied between the electrode and the bucket to joule heat the powder.

120. The system of Claim 119, wherein the reactor is bucket shaped.

121. The system of Claim 119, wherein the reactor is tube shaped with a removable bottom.

122. The system of Claim 119, wherein the system further comprises: a gas tight lid, a powder feeder penetrating the lid, and a powder dispenser on the bottom of the reactor.

123. The system of Claim 124, wherein the system can be operated in a continuous mode.

124. A system for joule heating powders, comprising: a graphite bucket reactor having ceramic bottom for holding conductive powder; and a stationary rotating electrode inserted into the bucket that can mix the powder, wherein electrical power can be applied between the electrode and the graphite bucket to joule heat the powder.

125. The system of Claim 124, wherein the bucket has a gas tight lid that is electrically insulated from the bucket.

126. The system of Claim 125, wherein the lid includes a gas outlet port.

127. The system of claim 126, further comprising a vacuum pump.

128. A system for joule heating of powders, comprising: a graphite bucket reactor for holding conductive powder comprising: a gas outlet port; a ceramic bottom; a gas tight lid that can slide over the bucket and that is electrically insulated from the bucket; and a moving electrode inserted into the bucket that can mix the powder;wherein electrical power can be applied between the electrode and the graphite bucket to joule heat the powder.

129. A system for joule heating powders, comprising: a graphite bucket reactor for holding conductive powder; and a rotating assembly comprising an electrode and electrically insulating stirring paddles, wherein the electrode is electrically insulated from the bucket bottom, and wherein the rotating assembly is inserted into the bucket to mix the powder, wherein electrical power can be applied between the electrode and the graphite bucket to joule heat the powder.

130. A system for joule heating powders, comprising: a graphite tube reactor for holding conductive powder, having a removable electrically insulating bottom; and a rotating assembly comprising of an electrode and electrically insulating stirring paddles, wherein the electrode is electrically insulated from the bucket bottom, and wherein the rotating assembly is inserted into the bucket to mix the powder, wherein electrical power can be applied between the electrode and the graphite bucket to joule heat the powder.

131. A system for joule heating powders, comprising: a graphite bucket reactor for holding conductive powder; and a movable graphite electrode, having an electrically insulating cup at its end, to insulate the electrode from the reactor bottom, the movable graphite electrode inserted into the reactor to mix the powder, wherein electrical power can be applied between the electrode and the graphite reactor to joule heat the powder.

132. A system for joule heating powders, comprising: a graphite tube reactor for holding conductive powder, the graphite tube reactor having removable bottom; and a movable graphite electrode inserted into the reactor to mix the powder,wherein electrical power can be applied between the electrode and the graphite reactor to joule heat the powder.

133. The system of Claim 132, wherein the removable bottom is electrically insulating.

134. The system of Claim 132, wherein the graphite electrode has an electrically insulating cup at its end, to insulate the electrode from the reactor bottom.

135. A method for thermal decomposition of gas, comprising: providing a volume of electrically conductive powder; permeating the volume of electrically conductive powder with a gas; wherein the gas comprises hydrogen and carbon; and joule heating the electrically conductive powder.

136. The method of Claim 135, wherein the gas comprises hydrocarbon or a mixture of hydrocarbon gases.

137. The method of Claim 136, wherein the hydrocarbons include at least one of methane, acetylene, ethylene, ethane, and propane.

138. The method of Claim 135, wherein the gas comprises natural gas that includes gases other than hydrocarbons.

139. The method of Claim 135 wherein the gas includes vaporized liquid hydrocarbons.

140. The method of Claim 135, wherein the gas is an organic compound that comprises carbon and hydrogen.

141. The method of Claim 135, wherein the gas is an organic compound that contains oxygen or nitrogen or both, in addition to carbon and hydrogen.

142. The method of Claim 135, wherein the gas is an organic compound that contains vaporized liquid organic compounds of hydrocarbons.

143. The method of Claim 142, wherein the liquid organic compound includes crude oil.

144. The method of Claim 135, wherein the gas is an organic compound that contains hydroxyl groups.

145. The method of Claim 135, wherein the gas is methane, and the decomposed gas is hydrogen.

146. A method for a thermally activated chemical reaction of gas and a reactant powder, using joule heating, comprising: combining the reactant powder with an electrically conductive powder; joule heating the combined reactant powder and electrically conductive powder; and flowing the gas through a volume of the combined reactant powder and electrically conductive powder; for the gas to undergo a thermally activated chemical reaction with the reactant powder.

147. The method of Claim 146, wherein the gas is chlorine, and the chemical reaction is chlorination of metal oxide, metal compound, or a combination thereof, to metal chlorides, wherein the reactant powder comprises metal oxide, metal compound, or a combination thereof.

148. The method of Claim 146, wherein the gas is hydrogen, and the chemical reaction is reduction of oxides, wherein the reactant powder comprises oxides.

149. The method of Claim 146, wherein the gas is hydrogen, and the chemical reaction is reduction of silicon dioxide into silicon, wherein the reactant powder comprises silicon dioxide.

150. The method of Claim 146, wherein there is more than one chemical reaction, wherein a first reaction is methane pyrolysis into at least hydrogen and carbon, and a second reaction is reduction of iron oxide with hydrogen from the methane pyrolysis, wherein the iron oxide is reduced to iron, wherein the reactant comprises of iron oxide.

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