CA3132545C

CA3132545C - Method for conversion of hydrocarbons via microwave-generated non-thermal plasma

Info

Publication number: CA3132545C
Application number: CA3132545A
Authority: CA
Inventors: Evan T. Musselman; George L. Skoptsov; James J. Strohm; Kurt W. Zeller
Original assignee: H Quest Vanguard Inc
Current assignee: H Quest Vanguard Inc
Priority date: 2017-08-08
Filing date: 2018-08-07
Publication date: 2023-09-12
Anticipated expiration: 2038-08-07
Also published as: CA3071559C; CA3132545A1; CA3071559A1

Abstract

In one embodiment there is provided a method for non-thermal plasma conversion of a precursor material to a product. Plasma forming material and a hydrocarbon precursor material are provided to a reaction zone. The plasma forming material is exposed to microwave radiation within the reaction zone. The exposure selectively converts the plasma forming material to non-thermal plasma. The non-thermal plasma forms one or more streamers. The hydrocarbon precursor material is exposed to both the one or more streamers and the microwave radiation. The exposure of the hydrocarbon precursor material selectively converts the hydrocarbon precursor material to a product, which in one embodiment may be in the form of a carbon enriched material(s) and a hydrogen enriched material(s).

Description

METHOD FOR CONVERSION OF HYDROCARBONS VIA MICROWAVE-GENERATED NON-THERMAL PLASMA
RELATED APPLICATIONS AND CLAIMS OF PRIORITY
[0001] This document claims priority to United States Patent Application No.
15/671,584, filed August 8, 2017 (now United States Patent No. 9,987,611), United States Patent Application No. 15/671,603, filed August 8, 2017, and United States Patent Application No. 15/671,629, filed August 8, 2017. This patent document also claims priority to United States Patent Application No. 15/997,495, filed June 4, 2018, which claims priority to and is a continuation-in-part of, United States Patent Application No.
15/671,584, filed August 8, 2017.

[0002]
BACKGROUND

[0003] The present embodiments relate to utilizing non-thermal plasma for conversion of a precursor material into a product. More specifically, the embodiments relate to utilizing microwave radiation to generate the non-thermal plasma which facilitates the conversion of the hydrocarbons to a product.

[0004] Plasma is a state of matter which contains electrons and at least partially ionized atoms and/or molecules (e.g., ions). Plasma may be, but not limited to, a thermal plasma and a non-thermal plasma. The thermal plasma is in local thermodynamic equilibrium where the electrons, ions, atoms, and molecules of the thermal plasma have a similar temperature. The non-thermal plasma is not in thermodynamic equilibrium. In the non-thermal plasma, the electrons have high electron temperatures comparative to the atoms, molecules, and/or ions which have a relatively low temperature.

[0005] Organic materials can be converted into products by pyrolysis.
Plasma may be used to facilitate the pyrolysis of organic materials. However, utilizing plasma may have high capital costs, recurring costs, and resource utilization (e.g., power, cooling, etc.).

Date Recue/Date Received 2022-03-15 Additionally, plasma can quickly deteriorate components of a reactor due to high temperatures and undesired side reactions.
SUMMARY
100061 A system is provided for utilizing microwave radiation to generate non-thermal plasma which facilitates the conversion of feedstock materials to a product 100071 In one aspect, a system is provided for plasma based synthesis of graphitic materials. In an embodiment, the system may include a plasma forming zone configured to generate a plasma from radio-frequency radiation, an interface element configured to transmit the plasma from the plasma forming zone to a reaction zone, and a the reaction zone configured to receive the plasma. The reaction zone is further configured to receive feedstock material comprising a carbon containing species, and convert the feedstock material to a product comprising the graphitic materials in presence of the plasma. The radio-frequency radiation may be microwave radiation. The plasma may be non-thermal plasma comprising a plurality of streamers.
100081 In an embodiment, the plasma forming zone may include a radiation source, and a discharge tube coupled to the radiation source configured to receive a plasma forming material. The discharge tube may be made from a material that is transparent to the radio-frequency radiation. Optionally, the plasma forming material may include one or more of the following: argon, hydrogen, helium, neon, krypton, xenon, carbon dioxide, nitrogen, and water. A waveguide may be configured to couple the radiation source to the discharge tube.
Alternatively and/or additionally, the system may include a reaction tube configured to surround the discharge tube in the plasma forming zone to form an annulus. The feedstock material flows in the annulus through the plasma forming zone before entering the reaction zone. A dielectric strength of the plasma forming material is less than a dielectric strength of the feedstock material. Optionally, the feedstock material may be introduced directly into the reaction zone without being exposed to the radio-frequency radiation in the plasma forming zone.
100091 In one or more embodiments, the reaction zone may include a reaction vessel formed from material that is opaque to the radio-frequency radiation. The reaction vessel may also include a resonant cavity.
100101 In at least one embodiment, the plasma transmitted from the plasma forming zone to the reaction zone may form a dense plasma head that is configured to transmit the radio-frequency radiation from the plasma forming zone to the reaction zone.

Date Recue/Date Received 2021-10-01 100111 In an embodiment, the reaction zone is further configured to receive a process gas.
[0012] In one or more embodiments, the feedstock material also comprises molecular hydrogen. Optionally, a molar ratio of the carbon containing species to the molecular hydrogen in the feedstock material is about 5:1 to about 1:1. In an embodiment, the feedstock material may include one or more of: aromatic, alkylated aromatic, paraffinic, olefinic, cycloolefin, napthenic, alkane, alkene, alkyl cycloalkane, alkylated cycoalkane, alkyne, alcohol, and heteroatom hydrocarbons. Additionally and/or alternatively, the feedstock material may include: methane, ethane, propane, butane, syngas, natural gas, methanol, ethanol, propanol, butanol, carbon dioxide, hexane, benzene, paraffins, polyaromatics, naphthalene, or a combination thereof.
[0013] In certain embodiments, the plasma forming material may include one or more first materials selected from the group consisting of: argon, hydrogen, helium, neon, krypton, xenon, carbon dioxide, nitrogen, and water.
[0014] In an embodiment, the graphitic material may be nano-graphene sheets, semi-graphitic particles, amorphous particles, or a combination thereof. The lateral dimensions of the nano-graphene sheets may be about 50 nm to about 500 nm. Additionally and/or alternatively, concentration of the nano-graphene sheets in the product may be proportional to a concentration of molecular hydrogen in the feedstock material.
In another aspect, a method is provided for plasma based synthesis of graphitic materials. In an embodiment, the method may include delivering a plasma forming material into a plasma forming zone, exposing the plasma forming material to radio-frequency radiation to generate a plasma, transmitting the plasma from the plasma forming zone to a reaction zone, delivering feedstock material comprising a carbon containing species to the reaction zone, and converting the feedstock material to a product comprising graphitic materials in presence of the plasma.
[0015] In another aspect, a system is provided for non-thermal plasma conversion of a precursor material to a product. A vessel is provided in communication with a first conduit, a second conduit, and a radiation source. The first conduit is configured to receive a first flow of a hydrocarbon precursor material. The second conduit is configured to receive a second flow of a plasma forming material. The vessel receives the materials from the first and second flows. The radiation source generates microwave radiation and exposes the materials from the first and second flows to the microwave radiation, with the exposure taking place in the vessel The exposure selectively converts the plasma forming material Date Recue/Date Received 2021-10-01 into non-thermal plasma. The non-thermal plasma forms one or more streamers.
Within the vessel, the first flow is exposed to the one or more streamers. The exposure of the first flow to both the microwave radiation and the formed streamers selectively converts the hydrocarbon precursor material to a product, which in one embodiment may be in the form of a carbon enriched material(s) and a hydrogen enriched material(s).
100161 In yet another aspect, a method is provided for non-thermal plasma conversion of a precursor material to a product. Plasma forming material and a hydrocarbon precursor material are provided to a reaction zone. The plasma forming material is exposed to microwave radiation within the reaction zone. The exposure selectively converts the plasma forming material to non-thermal plasma. The non-thermal plasma forms one or more streamers. The hydrocarbon precursor material is exposed to both the one or more streamers and the microwave radiation. The exposure of the hydrocarbon precursor material selectively converts the hydrocarbon precursor material to a product, which in one embodiment may be in the form of a carbon enriched material(s) and a hydrogen enriched material(s).
[0017] In certain embodiments, a plasma forming material is also provided to the reaction zone. The plasma promoter material the exposed to microwave radiation within the reaction zone, wherein the exposure selectively converts the plasma forming material to non-thermal micro-plasma formed between the plasma promoter material particles.
100181 These and other features and advantages will become apparent from the following detailed description of the presently preferred embodiment(s), taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
100191 The subject matter which is regarded as embodiments is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification.
The foregoing and other features, and advantages of the embodiments are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
100201 FIG. 1A depicts a block diagram illustrating a system for processing a precursor material into a product utilizing a non-thermal plasma, according to an embodiment.
100211 FIG. 1B depicts a block diagram illustrating a system for processing a precursor material into a product utilizing a non-thermal plasma in the presence of a plasma promoter material, according to an embodiment Date Recue/Date Received 2021-10-01 [0022] FIG. 2 depicts a block diagram illustrating a system for processing the precursor material into a product utilizing non-thermal micro-plasma and streamers, according to another embodiment.
[0023] FIG. 3A depicts a block diagram illustrating a flow configuration for processing a precursor material into the product utilizing the non-thermal plasma.
[0024] FIG. 3B depicts a block diagram illustrating a flow configuration for processing the precursor material into the product utilizing the non-thermal plasma in the presence of a plasma promoter material.
[0025] FIG. 4 depicts a block diagram illustrating another embodiment of a system for processing a precursor material into a product utilizing a non-thermal plasma.
[0026] FIG. 5 depicts a block diagram illustrating a second embodiment for processing a precursor material into the product utilizing the non-thermal plasma.
[0027] FIG. 6 illustrates the transmission electron microscopy (TEM) images of graphitic materials obtained by processing of methane in the absence of H7, according to an embodiment (TEM images (A) NG sheets with (B) semi-graphitic particles. (C) and (D) represent the morphological variability).
[0028] FIG. 7 illustrates the TEM images of graphitic materials obtained by processing of methane in the presence of H2 at a molar ratio of 2.5:1, according to an embodiment (TEM images (A) amorphous spheres possessing internal structure (B) fused semi-graphitic polyhedral particles and NG sheets, (C) a polyhedral particle along the edge of an NG sheet with an amorphous edge and (D) folded NG sheets).
100291 FIG. 8 illustrates the TEM images of graphitic materials obtained by processing of methane in the presence of H2 at a molar ratio of 1:1, according to an embodiment (1EM
images (A) and (C) show the morphology of NG sheets. (B) and (D) show semi-graphitic polyhedral particles).
[0030] FIG. 9 depicts a flow chart illustrating a method for processing the precursor material into the product utilizing the non-thermal plasma, according to an embodiment.
[0031] FIG. 10 depicts a flow chart illustrating a method for processing the precursor material into the product utilizing the non-thermal plasma, according to an embodiment.
[0032] FIG. 11 depicts a graph illustrating the emission spectra of the non-thermal plasma with respect to a distance traversed through the reaction zone.
[0033] FIG. 12 depicts a graph illustrating the emission spectra of the non-thermal plasma with respect to a distance traversed through the reaction zone in the presence of a plasma promoter material.
Date Recue/Date Received 2021-10-01 DETAILED DESCRIPTION
[0034] It will be readily understood that the components of the present embodiments, as generally described and illustrated in the Figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the apparatus, system, and method of the present embodiments, as presented in the Figures, is not intended to limit the scope of the embodiments, as claimed, but is merely representative of selected embodiments.
[0035] Reference throughout this specification to "a select embodiment,"
"one embodiment," or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present embodiments. Thus, appearances of the phrases "a select embodiment," "in one embodiment," or "in an embodiment" in various places throughout this specification are not necessarily referring to the same embodiment.
[0036] The illustrated embodiments will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and illustrates certain selected embodiments of devices, systems, and processes that are consistent with the embodiments as claimed herein.
[0037] Other than in any operating examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification and claims are to be understood as being modified in all instances by the term "about". The modifier "about"
used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., includes the degree of error associated with measurement of the particular quantity). Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties to be obtained. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits by applying ordinary rounding techniques.
[0038] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the embodiments are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently

6 Date Recue/Date Received 2021-10-01 contains certain errors necessarily resulting from the standard variation found in their respective testing measurements.
[0039] Unless the meaning is clearly to the contrary, all references made herein to ranges are to be understood as inclusive of the endpoints of the ranges. Also, it should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of "1 to 10" is intended to include all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10.
[0040] Unless the meaning is clearly to the contrary, all references made herein to pressures, such as psi, are to be understood as relative to atmospheric pressure.
[0041] The term "graphitic materials" refers to carbon containing solids including but not limited to. amorphous and graphitic carbon blacks of varying crystallinity, carbon onions and rosettes, graphite, graphene, functionalized graphene, and graphitic and graphenic carbon structures (containing one or more layers of graphene sheets), carbon nanotubes, functionalized CNTs (or hybrid CNTs, denoted HNTs), and carbon fiber. The graphitic materials may be flat (completely flat and/or may include curved or curled sections), curved, curled, rosette shaped, spheroidal, or the like.
100421 Generally, the present embodiments relate to utilizing non-themial plasma for conversion of a precursor material into a product. More specifically, the embodiments relate to utilizing microwave radiation to generate non-thermal plasma which facilitates conversion of hydrogen and/or carbon-containing gases and/or other materials to products such as, without limitation, graphitic materials (including graphene), chemicals (e.g., ammonia) and/or hydrogen.
[0043] The current disclosure describes methods and systems for synthesis of graphitic materials that have unique structures and properties (described below).
Furthermore, the synthesis of graphene is scalable to different scales In general, the rate of production of desired material (kg/hr product produced) is a function of the microwave power consumed in the process (kW) divided by the energy requirement per unit feedstock converted (kWhr/kg feedstock converted), and multiplied by the product of feedstock conversion rate (%), product selectivity (%), and the molar mass ratio of product to feedstock. For example, the production rate of graphitic materials may be defined by the power absorbed (kW) divided by the energy per unit feedstock required (kWhr/kg methane converted), multiplied by the feedstock conversion rate (%), multiplied by the molar mass ratio of product to

7 Date Recue/Date Received 2021-10-01 feedstock (12.01 g/mol carbon divided by 16.04 g/mol methane). In an embodiment, the power consumed in the process is about 0.1 to about 1 kW. In another embodiment, the power consumed in the process is about 1 to about 15 kW. In another embodiment, the power consumed in the process is about 1 to about 100 kW. The of energy required per unit feedstock is about 1 Whr/kg to about 100 kWhr/kg of feedstock converted. In an embodiment, the power required per unit feedstock is about 1.24 to about 60 kWhr per kg of methane converted, and more preferably about 5 to about 15 kWhr per kg of methane converted, and most preferably about 9 to about 11 kWhr per kg of methane converted. In an embodiment, the conversion rate of feedstock material is about 0.1% to about 100%, more preferably about 50% to about 100%, and most preferably about 75% to about 99%. In an embodiment, the product selectivity is about .1% to about 100%, more preferably about 10% to about 80%, and most preferably about 70% to about 79%.
[0044] The graphitic materials can be synthesized at rates of about 1 g/hour to about 1 g/min, about 0.001 Kg/min to about 0.2 Kg/min, about 0,2 Kg/min to about 4.1 Kg/min, or more preferably about 0.7 Kg/min to about 2.4 Kg/min, or most preferably about 1.4 Kg/min to about 2.0 Kg/min. This synthesis of graphitic materials is achieved using a novel microwave plasma reactor, as discussed below. A non-thermal plasma environment provides conditions of high electron temperature and high reactivity near atmospheric pressures (about 0.9 - 1.1 bar) for decomposition of carbon-containing compounds resulting in a variety of graphitic materials including graphene sheets. Furthermore, one or more reactor zone parameters may be varied to selectively produce one or more types of graphitic materials. For example, molecular hydrogen may be introduced in the reaction zone for minimizing the formation of other carbon nanostmctures while increasing the yield of graphene sheets formed in the process. Similarly, the yield and quality of graphene sheets formed may be varied through varying the process parameters. Operation at near atmospheric pressures is desirable due to elimination of costly equipment such as compressors and vacuum pumps, and reduction of demands on reactor hardware (e.g.
reactor and piping material thickness and composition), thus resulting in overall reduction of capital costs. In order to achieve specific product types, selectivities, energy and/or conversion efficiencies, or product properties, the process may be operated at various pressures such as, without limitation, highly reduced (about 1 torr ¨ 100 torr), reduced (about 100 torr ¨ 0.9 bar), increased (about 1.1 bar ¨2 bar), high (about 2 bar ¨ 10 bar), and very high (about 10 bar ¨40 bar) pressures.

8 Date Recue/Date Received 2021-10-01 [0045] Plasma is a state of matter which contains electrons and at least partially ionized atoms and/or molecules (e.g., ions). Plasma may be, but not limited to, a thermal plasma and a non-thermal plasma. The thermal plasma is in local thermodynamic equilibrium where the electrons, ions, atoms, and molecules of the thermal plasma have a similar temperature. The non-thermal plasma is not in thermodynamic equilibrium.
[0046] Thermal plasma can be created by passing a gas, such as argon, through an electric arc. The electric arc will rapidly heat the gas by resistive and radiative heating to a high temperature (>9000 degrees Kelvin) within milliseconds of passing through the arc generating electrons and ions from the gas. The thermal plasma has electrons and ions which have similar energy distributions (e.g., in thermodynamic equilibrium).
However, the high temperature(s) may be detrimental to the reactants and/or products Moreover, generating thermal plasma(s) may have large energy requirements and capital costs.
Additionally, utilizing thermal plasma(s) to support conversion of a hydrocarbon results in production of low-value carbon (e.g., soot).
[0047] On the other hand, in the non-thermal plasma, the electrons have high electron temperatures comparative to the atoms, molecules, and/or ions which have a relatively low temperature. A non-thermal plasma can be created to have a density of electrons at or above the critical density. The critical density is defined as the electron density at which the electron frequency is equivalent to the electromagnetic driving frequency. At this condition, incident electromagnetic waves exponentially decay in energy magnitude as they propagate within the plasma structure. Additionally, electromagnetic energy is conducted along the surface of the plasma. Hence, the non-thetinal plasma may also act as a conduit for transmission of electromagnetic energy similarly to an antenna when it is at or above the critical density.
[0048] In certain embodiments, systems and methods are provided to efficiently generate non-thermal plasma for conversion of precursor materials to products while avoiding formation of reaction-disrupting deposits. More specifically, the non-thermal plasma (that may also act as a conduit for microwave radiation) and a precursor material are provided to the reaction zone of a vessel. The non-thermal plasma is created by exposing a plasma forming material to microwave radiation outside of the reaction zone.
The exposure of the plasma forming material to the microwave radiation selectively converts the plasma foiming material to the non-thermal plasma. In an embodiment, the non-thermal plasma may form one or more streamers. Alternatively and/or additionally, the non-thermal plasma may form diffused plasma (e.g., at high powers such as power > 4kW). The precursor

9 Date Recue/Date Received 2021-10-01 material is exposed to the non-thermal plasma in the reaction zone for selective conversion of the precursor material to a product comprising graphitic materials. The product may also include chemicals such as ammonia and/or hydrogen.
[0049] In one or more embodiments, a plasma promoter material is also provided to the reaction zone of a vessel. The reaction zone is exposed to microwave radiation, which exposes the plasma forming material, the precursor material, and the plasma promoter material to the microwave radiation. The exposure of the plasma forming material and the plasma promoter material to the microwave radiation selectively converts the plasma forming material to the non-thermal micro-plasma. As used herein, micro-plasma refers to a localized plasma region formed around a plasma promoter molecule. The exposure of the precursor material to the non-thermal micro-plasma and the microwave radiation selectively converts the precursor material to a product.
[0050] Referring to FIG. IA, a block diagram 100 is provided illustrating a system for processing a precursor material into a product utilizing the non-thermal plasma In the system shown herein, a vessel 102 is provided to facilitate processing of the precursor material. More specifically, the vessel 102 is configured with a cavity 110 and a reaction zone 104 within the cavity 110. The reaction zone 104 is configured to facilitate interaction of and/or mixing of various material(s) and generation of non-thermal plasma 150. The vessel is provided with a vessel boundary 102a (e.g., walls) to support and/or maintain the reaction zone 104. The size and/or location of the reaction zone 104 and/or non-thermal plasma 150 is for illustration purposes and is not limited to the identified region. The size and/or location of the reaction zone 104 and/or non-thermal plasma 150 may be dynamic.
For example, in one embodiment, the reaction zone 104 may extend to the vessel boundary.
The vessel boundary 102a may be comprised of any known or conceivable material capable of withstanding the heat, pressure(s), and chemical environments associated with generating and/or sustaining the non-thermal plasma. For example, the material of vessel boundary 102a may be a microwave radiation opaque material (e.g., limits penetration of microwave radiation through the material). The microwave radiation opaque material may be, but is not limited to ceramics and metals or metal alloys, such as brass, copper, steel, nickel, stainless steel, titanium, and aluminum. In one embodiment, the vessel boundary 102a is constructed of a microwave radiation reflective material. In one embodiment, the vessel 102 is operated at atmospheric pressure. Accordingly, the vessel 102 is configured to withstand the heat, pressure(s), and chemical environment(s) associated with processing the precursor material.
1.(31 Date Recue/Date Received 2021-10-01 [0051] As shown, the vessel 102 is provided with multiple conduits for controlling ingress and egress of materials to and from the cavity 110, and more specifically, controlling ingress and egress to and from the reaction zone 104. For example, a first conduit 120 and a second conduit 122 are provided in communication with a first side 106 of the vessel 102. The first conduit 120 is at a first angle al with respect to the vessel 102 and the second conduit is at a second angle az with respect to the vessel 102.
The positioning and orientation of the first and second conduits, 120 and 122, respectively, is for illustration purposes and should not be considered limiting. For example, in one embodiment, the first and second conduits, 120 and 122, respectively, may be provided in communication with different sides or boundaries of the vessel 102 and the first angle ai and second angle az may be the same or may be different.
[0052] Regardless of the positioning, the first and second conduits, 120 and 122, respectively, control and/or facilitate ingress of material(s) to the cavity 110 of vessel 102, including ingress of materials to the reaction zone 104. Namely, the first conduit 120 is operatively coupled to a first material source 130. For example, the first conduit 120 is shown herein to control and/or facilitate ingress of a plasma forming material 130a provided by the first material source 130 at a first flow rate to the reaction zone 104. In one embodiment, the first flow rate may have a gas hourly space velocity (GHSV) of 14,500 to 32,000 per hour, in another embodiment, the flow rate may have a GHSV of 100 to 14,500 per hour, and in another embodiment the flow rate may have a GHSV of 32,000 to 240,000 per hour. In one embodiment, the GHSV is measured at standard temperature and pressure STP (e.g., 273.15 degrees Kelvin and 1 atmosphere of pressure) based on a volume of the reaction zone 104.
[0053] As shown, the second conduit 122 is operatively coupled to a second material source 132. For example, the second conduit 122 is shown herein to control and/or facilitate ingress of a precursor material 132a provided by material source 132 at a second flow rate to the reaction zone 104. The second flow rate may have a GHSV of 100 to 14,500 per hour, in another embodiment, the second flow rate may have a GHSV of 14,500 to 32,000 per hour, and in another embodiment the second flow rate may have a GHSV of 32,000 to 240,000 per hour. In one embodiment, the first flow has a minimal flow rate (e.g. GHSV of less than 100 per hour) and the second flow has the bulk flow rate (e.g., GHSV
of greater than 1000 per hour and up to 240,000 per hour). In another embodiment, the flow rates may be reversed such that the first flow may has the bulk flow rate and the second flow has the minimal flow rate. In one embodiment, the first and/or second flow has solid particles Date Recue/Date Received 2021-10-01 entrained within the respective flow. In one embodiment, the first and second conduits, 120 and 122, respectively, may be, but are not limited to, a pipe, a tube, an orifice, a channel, a nozzle, an inlet, and combinations thereof. In one embodiment, the first and/or second conduits, 120 and 122, respectively, may be provided with a single injection port, or multiple injection ports. Accordingly, the first and second conduits, 120 and 122, respectively, control ingress of materials to the reaction zone 104.
100541 In another embodiment, a plasma promoter may be used to generate one or more micro-plasmas. As shown in FIG. 1B, at least one of the first conduit 120 and the second conduit 122 is operatively coupled to a third material source 136. For example, in one embodiment, the second conduit 122 may control and/or facilitate ingress of a plasma promoter material 136a provided by material source 132 at a third flow rate to the reaction zone 104. In one embodiment, the first conduit 120 may control and/or facilitate ingress of a plasma promoter material 136a provided by material source 132 at the third flow rate to the reaction zone 104. In one embodiment, the first and second conduits, 120 and 122, respectively, both control and/or facilitate ingress of the plasma promoter material 136a at the third flow rate to the reaction zone 104. In one embodiment, a sixth conduit (not shown) is operatively coupled to the third material source 136 and may control and/or facilitate ingress of the plasma promoter material 136a to the reaction zone 104.
Accordingly, the plasma promoter material 136a may be provided to the reaction zone 104 in a variety of different manners. The third flow rate may be 0.03 to 3.5 grams per liter of gas reactant flow (e.g., grams of plasma promoter material 136a per liter of plasma forming material 130a and/or precursor material 132a), in another embodiment, the third flow rate may be 3.5 to 10.0 grams per liter of gas reactant flow, and in another embodiment the third flow rate may be 10 to 35 grams per liter of gas reactant flow.
100551 The plasma promoter material 136a may comprise virtually any material that can be used to promote the generation of plasma, such as, but not limited to, the non-thermal plasma 150 including to promote the generation of micro-plasma 150a. For example, the plasma promoter material 136a may include, but is not limited to carbon black, coal, biochar, biomass, graphite, activated carbon, a transition metal, a supported transition metal, structured carbon, and combinations thereof. The transition metal may be, but is not limited to, iron, nickel, copper, molybdenum, tungsten, cobalt, palladium, and ruthenium. The transition metal may be supported on, but not limited to, carbon, alumina, silica, titanium oxide, magnesium oxide, carbon based materials, carbide based materials, and combinations thereof. It is understood that the plasma promoter material 136a may not be pure and may Date Recue/Date Received 2021-10-01 contain a variety of impurities as known in the art. In one embodiment, the plasma forming material 130a may include the precursor material 132a, and/or a recycled process gas containing an intermediate product, product 134a, plasma forming material 130a, and/or unreacted precursor material 132a. Accordingly, the plasma promoter material 136a facilitates the generation of the non-thermal plasma 150.
100561 The plasma promoter material 136a is dispersed into the reaction zone 104 in a manner such that particles (e.g., liquid droplets, solids, etc.) of the plasma promoter material 136a have a degree a separation as shown in the magnified view 104a of the reaction zone 104. For example, at least two portions of the plasma promoter material 136a are separated from one another by a secondary material such as, but not limited to, the plasma forming material 130a and the precursor material 132a. In one embodiment, the plasma promoter material 136a may contain solid particles 136a. The solid particles may be entrained within a gas flow. In one embodiment, the plasma promoter material 136a may be entrained within a flow of the plasma forming material 130a within the first conduit 120.
Similarly, in one embodiment, the plasma promoter material 136a may be entrained within a flow of the precursor material 132a within the second conduit 122. Similarly the plasma promoter material 136a may be fed into the reaction zone without being dispersed and upon exposure to the plasma forming material 130a and/or precursor material 132a within the reaction zone 104, the plasma promotor material 136a becomes dispersed within the plasma forming material 130a and/or precursor material 132a.
100571 As used herein, the term "precursor" refers to a substance from which a product 134a is formed. The precursor material 132a may comprise virtually any material, depending upon the desired composition of the product 134a to be foitned. The precursor material 132a may comprise a hydrocarbon(s), hereinafter referred to as a hydrocarbon precursor material. The precursor material 132a may be a hydrocarbon such as, but is not limited to, aromatic, alkylated aromatic, paraffinic, olefinic, cycloolefin, naphthenic, alkane, alkene, alkyl cycloalkane, alkylated cycoalkene, alkyne, alcohols, and a carbon and hydrogen based compound(s) containing one or more heteroatoms (e.g., a thiophene and a furan), and combinations thereof. For example, the precursor material 132a may be, but is not limited to, methane, ethane, propane, butane, syngas, natural gas, ethylene, acetylene, methanol, ethanol, propanol, butanol, hexane, benzene, paraffin, naphthalene, styrene, vinyl chloride, 1,2-dichloroethane, allyl alcohol, propionaldehyde, vinyl bromide, and combinations thereof. It is understood that the precursor material 132a may not be pure and can contain a variety of impurities as known in the art. For example, the precursor material Date Recue/Date Received 2021-10-01 132a can include the plasma forming material 130a and/or a recycled process gas containing an intermediate product, product 134a, plasma forming material 130a, and/or unreacted precursor material 132a.
[0058] The plasma forming material 130a may comprise virtually any material that can be used to generate plasma, such as, but not limited to, the non-thermal plasma 150. For example, the plasma forming material 130a may be, but is not limited to argon, hydrogen, helium, neon, krypton, xenon, carbon dioxide, nitrogen, synthesis gas, and water. It is understood that the plasma forming material 130a may not be pure and may contain a variety of impurities as known in the art. In one embodiment, the plasma forming material 130a may include precursor material 132a and/or a recycled process gas containing an intermediate product, product 134a, plasma forming material 130a, and/or unreacted precursor material 132a. In one embodiment, the plasma forming material 130a is chosen to have a first dielectric strength that is less than a second dielectric strength of the precursor material 132a. The lower dielectric strength of the plasma forming material 130a in comparison to the precursor material 132a facilitates non-thermal plasma 150 generation from the plasma forming material 130a. In one embodiment, the generation of the non-thermal plasma 150 from the plasma forming material 130a is initiated prior to plasma generation from the precursor material 132. Accordingly, the plasma forming material 130a is used to generate the non-thermal plasma 150.
[0059] The plasma forming material 130a, the precursor material 132a, and the plasma promoter material 136a (if present) are collectively referred to as reactants.
The temperature of the reactants may be individually and/or collectively controlled or uncontrolled (e.g., subject to environmental fluctuations in temperature) within the first and second conduits, 120 and 122, respectively. In one embodiment, the plasma forming material 130a is at a first temperature upon entering the first conduit 120, the precursor material 132a is at a second temperature upon entering the second conduit 122, and the plasma promoter material 136a is at a third temperature upon entering the first conduit 120 and/or second conduit 122.
In one embodiment, the first, second, and third temperatures are between 100 and 1,000 degrees Kelvin and more preferably between 250 and 500 degrees Kelvin.
Accordingly, the reactants may be provided to the vessel 102 with or without pre-heating and/or pre-cooling.
[0060] As shown, a third conduit 124 is provided in communication with a second side (108) of the vessel 102. The third conduit 124 controls and/or facilitates egress of material(s) from the cavity 110 of vessel 102, including egress of material(s) from the reaction zone 104. Namely, the third conduit 124 controls egress of a stream 134 from the Date Recue/Date Received 2021-10-01 reaction zone 104. The stream 134 may include, but is not limited to, the product 134a, the plasma forming material 130a (e.g., unconverted, extinguished non-thermal plasma, etc.), the precursor material 132a (e.g., unconverted, partially converted, etc.), the plasma promoter material 136a, and combinations thereof. In one embodiment, the third conduit 124 may be, but is not limited to, a pipe, a tube, an orifice, a channel, a nozzle, an outlet, and combinations thereof. The positioning of the third conduit 124 is for illustration purposes and should not be considered limiting. Accordingly, the third conduit 124 controls egress of materials from the reaction zone 104.
[0061] Each conduit 120, 122, and 124 is enclosed within a fixed boundary (e.g., walls).
For example, the first conduit 120 is shown with a first boundary 120a, the second conduit 122 is shown with a second boundary 122a, and the third conduit 124 is shown with a third boundary 124a. The boundaries, 120a, 122a, and 124a, may be constructed of the same material, or in one embodiment different materials. For example, the boundaries may be constructed of, but not limited to, a microwave radiation opaque material, microwave radiation reflective material, and a microwave radiation transparent material (e.g., allows microwave radiation to penetrate through the material). The material of the boundaries, 120a, 122a, and 124a, may be any known or conceivable material capable of withstanding the heat, pressure(s), and chemical environmental associated with transporting materials within the respective conduit and/or generating the non-thermal plasma 150.
For example, the boundaries, 120a, 122a, and 124a, may be may be comprised of a material such as, but are not limited to ceramics, glasses, and metals or metal alloys, such as brass, copper, steel, nickel, stainless steel, titanium, and aluminum. Accordingly, the materials of boundaries, 120a, 122a, and 124a, are capable of supporting transport of the reactants and the stream 134 within first, second, and third conduits, 120, 122, and 124, respectively.
As shown, a radiation source 140 is provided operatively coupled to the vessel 102. The radiation source 140 generates radio frequency (RE) radiation and/or microwave radiation, hereinafter referred to collectively as microwave radiation 140a. The frequencies of the microwave radiation 140a may be in the range from 36 megahertz (MHz) to 300 gigahertz (GHz), more preferably 40 MHz to 6 GHz, and most preferably 400 MHz to 3 GHz.
For example, the microwave radiation frequency may be, but is not limited to, 915 MHz and 2.45 GHz. The radiation source 140 may be, but is not limited to, a magnetron.
[0062] The operative coupling of the radiation source 140 to the vessel 102 facilitates subjecting the reaction zone 104 to the microwave radiation 140a, which facilitates a selective conversion of precursor material 132a to product 134a and generation of the non-Date Recue/Date Received 2021-10-01 thermal plasma 150 (and may include generation of a micro-plasma 150a). In one embodiment, the coupling between radiation source 140 and vessel 102 is direct. In one embodiment, a waveguide 142 is provided between and in communication with the radiation source 140 and the vessel 102. In one embodiment, there are a plurality of radiation sources 140. The plurality of radiation sources 140 may be coupled to a single waveguide 142 or a plurality of waveguides 142. Regardless of the coupling method, the microwave radiation 140a within the reaction zone 104 is at a concentration ranging from 100 watts (W) per liter to 300 Kilowatts (kW) per liter within the reaction zone 104, more preferably between 1 and 80 kW per liter within the reaction zone 104, and most preferably between 2 and 30 kW per liter within the reaction zone 104. In one embodiment, the microwave radiation 140a within the reaction zone 104 is at a concentration of less than 50 kW per liter, more preferably less than 30 kW per liter, and most preferably less than 15 kW
per liter. Accordingly, the reaction zone 104 is subjected to microwave radiation 140a generated by the radiation source 140.
[0063] Within the reaction zone 104, the reactants are subject to mixing and/or interaction with one another and exposed to the microwave radiation 140a. In one embodiment, the reactants traverse through the reaction zone 104 in flow direction 144. The exposure of at least one of the reactants to the microwave radiation 140a generates the non-thermal plasma 150. More specifically, adsorption of microwave energy 140a promotes electron and ion impacts/collisions within but not limited to a portion of atoms and/or molecules of the plasma forming material 130a and/or precursor material 132a, which results in ionization of the portion of atoms and/or molecules of the plasma forming material 130a and/or precursor material 132a. In one embodiment, the plasma forming material 130a is at least partially ionized (e.g., greater than 0 percent to 100 percent) and converted to the non-thermal plasma 150. Elastic and inelastic collisions between species, such as but not limited to electrons, non-thermal plasma 150, ions, atoms and/or molecules of plasma forming material 130a and/or precursor material 132a, radical species, product 134a, and/or intermediate product(s) present in the reaction zone 104 results in energy transfer either directly or indirectly to the plasma forming material 130a, precursor material 132a, product 134a, and/or intermediate product(s). Energy transfer can excite (and/or increase the energy level) vibrational, electronic, rotational, and translational energy state(s) of the atoms and/or molecules of the plasma forming 130a and/or precursor material 132a.
In one embodiment, transfer of energy to vibrational and electronic energy states is greater than transfer of energy to translational energy state within the non-thermal plasma 150. In Date Recue/Date Received 2021-10-01 one embodiment the energy states of the non-thermal plasma are not in thermodynamic equilibrium such that the electron and/or vibrational temperature are greater than rotational, ion, and/or translation temperatures. In one embodiment the measured temperature of various excited species present in the non-thermal plasma 150 are not equal.
For example, the plasma forming material 130a may have electrons at a first temperature which is different than a second temperature of C2 species present in the reaction zone 104 and/or different than a blackbody temperature of the reaction zone 104. In one embodiment, the precursor material 132a is at least partially converted to the non-thermal plasma 150.
Accordingly, the non-thermal plasma 150 is generated within the reaction zone 104 by the microwave radiation 140a.
100641 Referring to FIG. 1B, when the generation of plasma includes generation of a micro-plasma, the exposure of at least one of the reactants to the microwave radiation 140a generates the non-thermal plasma 150 including generates micro-plasma 150a More specifically, in one embodiment, upon subjecting the plasma promoter material 136a to the microwave radiation 140a, one or more particles, such as first particle 136ai, of the plasma promoter material 136a accumulate an electric charge. Upon accumulating a threshold electric charge (e.g., the dielectric strength of the plasma forming material 130a), the plasma forming material 130a becomes locally ionized proximally to the first particle 136a1 in the form of micro-plasma 150a. In one embodiment, the micro-plasma 150a may have a shape which encompasses a shape of the first particle 136a3. Accordingly, a single particle may ignite the micro-plasma 150a. The micro-plasma 150a may also be ignited between multiple particles. For example, upon subjecting the plasma promoter material 136a to the microwave radiation 140a, two or more particles, such as second and third particles, 136a2 and 136a3, respectively, of the plasma promoter material 136a accumulate an electric charge. In one embodiment, the second particle 136a2 is positively charged. In one embodiment, the second particle 136a2 is negatively charged. In one embodiment, the charge accumulation on the third particle 136a3 may be the same net charge as the second particle 136a2 (e.g., both negative or both positive), and the net charges of the second and third particles, 136a2 and 136a3, respectively, may have a localized charge differential(s) resulting in an electric potential differential between the second and third particles, 136a2 and 136a3, respectively. Regardless, of which type of charge the second particle 136a2 accumulates, the electric potential difference is created between the second and third particles, 136a2 and 136a3, respectively. In one embodiment, the plasma forming material 130a and/or precursor material 132a may act as an insulator between the second and third Date Recue/Date Received 2021-10-01 particles, 136a2 and 136a3, respectively. The insulator enables particles that are not touching but may be closely spaced to have varying electric charges. Accordingly, the type of charge and particles which accumulate the charge is for illustration purposed only and should not be considered limiting.
[0065] In one embodiment, upon subjecting the plasma forming material 130a to the microwave radiation 140a which meets or exceeds the dielectric strength of the plasma forming material 130a, a valence electron is activated and/or excited from a first atom and/or molecule in the plasma forming material 130a. Upon excitation, the valence electron is removed from the first atom and/or molecule within the plasma forming material 130a and accelerated in a select direction based on a first electric field 114 generated by the microwave radiation 140a within the vessel 102. The accelerated electron strikes a second atom and/or molecule within the plasma forming material 130a causing removal of an electron from the second atom and/or molecule. The electron removal process progresses through the reaction zone 104 in this manner and results in an electron avalanche. The electrons within the electron avalanche have a first electron temperature.
[0066] Each micro-plasma 150a may increase a second electrical potential difference between the particles utilized to form the micro-plasma 150a and a secondary adjacent particle(s) (not shown). Upon increasing of the second electric potential difference, a second micro-plasma (not-shown) is generated between the particles utilized to form the micro-plasma 150a and the secondary adjacent particle(s). The non-thermal plasma 150 and micro-plasma 150a generation process progresses through the reaction zone 104 in this manner. Accordingly, the micro-plasma 150a is formed locally between particles and may initiate other micro-plasma(s).
[0067] Referring back to FIGS. IA, 2A, and 3A, the electron avalanche comprises an ionized head region which is proximal to the direction of propagation of the electron avalanche and proximal to an adjacently positioned tail region. A space charge is produced by the electron avalanche causing a distortion of a second electric field 116 within the electron avalanche such that free electrons move towards the ionized head region, thereby increasing the strength of the second electric field 116 within the electron avalanche. The increase in the strength of the second electric field 116 facilitates additional electron avalanches to cumulate in the ionized head region causing the quantity of free electrons in the ionized head region to increase, which increases the strength of the second electric field 116. As the electron avalanche propagates, the positive ions (e.g., the atoms and/or molecules that have at least one electron removed) are left in the tail region of the electron Date Recue/Date Received 2021-10-01 avalanche. The tail region progresses through the reaction zone 104 slower than the ionized head region progresses through the reaction zone 104. An increase in free electrons in the ionized head region causes the first electric field 114 inside of the vessel 102 to increase in strength.
100681 As the electron avalanche progresses through the reaction zone 104 and the first electrical field 114 within the vessel 102 increases to a threshold charge, the ionized head region begins to decelerate and the electron temperature of the ionization head region decreases to a second electron temperature. In one embodiment, the second electron temperature is less than the first electron temperature. Following the deceleration, the electron avalanche transitions into a streamer discharge 150a, hereinafter referred to as a streamer. In one embodiment, the streamer 150a is a type of non-thermal plasma with an excess of free electrons Similarly, in one embodiment, the streamer 150a has a longitudinal size that exceeds its transverse radius. A distortion of the sizing of the streamer 150a results in a radiation intensity (e.g., degree of ionization, electron temperature, etc.) in the longitudinal direction of the streamer 150a that is higher than the radiation intensity in the radial direction of the streamer. In one embodiment, the longitudinal direction of the streamer 150a is relatively parallel to the flow direction 144 within the reaction zone 104. In one embodiment, the radial direction of the streamer is relatively perpendicular to the flow direction 144.
100691 Upon transition of the electron avalanche to the streamer 150a, the electron temperature within the streamer 150a continues to decrease to a third electron temperature.
In one embodiment, the third electron temperature is less than the second electron temperature. In one embodiment, the third electron temperature is between 800 and 6,000 degrees Kelvin, more preferably between 900 and 3,000 degrees Kelvin, and more preferably between 1,000 and 2,500 degrees Kelvin. In one embodiment, the third electron temperature is not subject to an increase in temperature after a threshold microwave radiation density is reached within the reaction zone 104. In one embodiment, the threshold microwave radiation density within the reaction zone 104 is 15 kW per liter, more preferably 9 kW per liter, and more preferably 4 kW per liter. It is understood that the threshold microwave radiation density may be dependent on the reactants introduced to the reaction zone 104 and/or configuration of the reaction zone 104, thus the threshold microwave radiation density may vary from the values illustrated.
Additionally, due to the increase of strength in the first and second electrical fields, 114 and 116, respectively, additional electron avalanche(s) are initiated resulting in additional streamers 150a. The Date Recue/Date Received 2021-10-01 additional electron avalanches may be negative charge directed (e.g., propagating towards a negative charge) and/or positively charge directed (e.g., propagating towards a positive charge). Alternatively and/or additionally the threshold microwave radiation density may be dependent on the space between particles of the plasma promoter material 136a.
100701 The streamers 150a and/or the non-thermal plasma 150 within reaction zone 104 are transient and dynamically changing. In one embodiment, any single streamer 150a is only present for a short period of time (e.g., less than 1 second). In one embodiment, the non-thermal plasma 150 has a non-uniform radiation intensity (e.g, degree of ionization, electron temperature, etc.) within the reaction zone 104. For example, there is an area(s) of high radiation intensity 152a (e.g., the streamers 150a), and an area(s) of low radiation intensity 152b (e.g., absence of streamers 150a). In one embodiment, the area(s) of high radiation intensity 152a is at the third electron temperature while the area(s) of low radiation intensity 152b is at fourth electron temperature. In one embodiment, the fourth electron temperature is lower than the third electron temperature.
Accordingly, the non-thermal plasma 150 may be constantly and/or dynamically changing within reaction zone 104. In another embodiment, the non-thermal plasma 150 is primarily formed from the plasma forming material 130a For example, on a molar basis, the non-thermal plasma 150 is comprised of at least 50 percent plasma forming material 130a, in another embodiment, the non-thermal plasma 150 is comprised of at least 75 percent plasma forming material 130a ions and electrons, and in another embodiment the non-thermal plasma 150 is comprised of at least 90 percent plasma forming material 130a ions and electrons. The non-thermal plasma 150, including the micro-plasma 150a, initiates and/or continues selective conversion of the precursor material 132a to the product 134a. For example, the micro-plasma 150a may act as an energy transfer catalyst activating the precursor material 132a.
The ions and electrons within the micro-plasma 150a collide with the precursor material 132a. The collisions result in energy transfer sufficient to promote cleavage of a bond (e.g., hydrogen atom to a carbon atom bond) of the precursor material 132a. For example, if the precursor material 132a is methane, the H3C-H bond is cleaved by the collisions [0071] In one embodiment, the streamers 150a are primarily formed from the plasma forming material 130a. For example, on a molar basis, the streamers are comprised of at least 50 percent plasma forming material 130a, in another embodiment, the streamers are comprised of at least 75 percent plasma forming material 130a ions and electrons, and in another embodiment the streamers are comprised of at least 90 percent plasma forming material 130a ions and electrons. The streamers 150a initiate and/or continue selective Date Recue/Date Received 2021-10-01 conversion of the precursor material 132a to the product 134a. For example, the streamers 150a may act as an energy transfer catalyst activating the precursor material 132a. The ions and electrons within the streamers 150a collide with the precursor material 132a. The collisions result in energy transfer sufficient to promote cleavage of a bond (e.g., hydrogen atom to a carbon atom bond) of the precursor material 132a. For example, if the precursor material 132a is methane, the H3C-H bond is cleaved by the collisions.
[0072] Following interaction with the streamers 150a, the precursor material 132a, plasma forming material 130a, and/or streamers 150a form a convergence point 150b within the non-thermal plasma 150. At the convergence point 150b, the non-thermal plasma 150 dynamically changes composition. For example, the streamers 150a formed from the plasma forming material 130a converge, and in one embodiment, begin to extinguish (e.g., become less ionized). In one embodiment, the precursor material 132a receives a threshold amount of energy from the collision(s) with the ions and electrons within the non-thermal plasma 150 and/or receives a threshold amount of energy from the microwave radiation 140a wherein the precursor material 132a is at least partially ionized (e.g., greater than 0 percent to 100 percent). After receiving the threshold amount of energy, the precursor material 132a selectively converts into a non-thermal plasma 150c within the convergence point 150b. In one embodiment, the non-thermal plasma 150c has a C2 species temperature range of 1,500 to 5,500 degrees Kelvin, and in one embodiment, a C2 species temperature range of 2,000 to 3,500 degrees Kelvin. In one embodiment, the radiation intensity of the non-thermal plasma 150 is more uniform at the convergence point 150b than at the streamers 150a. Accordingly, the non-thermal plasma 150 changes composition along a distance of the reaction zone 104.
[0073] Exposure of the precursor material 132a to the reaction zone 104 including exposure to the streamers 150a, microwave radiation 140a, and convergence point 150b, selectively converts the precursor material 132a into the product 134a. In one embodiment, the product 134a comprises a carbon enriched material and a hydrogen enriched material.
The carbon enriched material has a hydrogen atom to carbon atom ratio of less than or equal to one. For example, the carbon enriched material may include, but is not limited to, a graphitic material, amorphous carbon, structured carbon, and ordered carbon.
The carbon enriched material may include graphene and/or graphite. The hydrogen enriched material has a hydrogen atom to carbon atom ratio greater than 1. The hydrogen enriched material may include, but is not limited to, hydrogen, ethylene, acetylene, butadiene, butane, and combinations thereof. In one embodiment, the conversion percentage of the precursor Date Recue/Date Received 2021-10-01 material 132a to the product 134a on a molar basis may be, but is not limited to, at least 5 percent, at least 30 percent, at least 70 percent, at least 90 percent, and at least 99 percent.
For example, in one embodiment, the conversion percentage of the precursor material 132a to the product 134a on a molar basis of may be between 30 and 70 percent.
Accordingly, the precursor material 132a is selectively converted to the product 134a within reaction zone 104.
100741 In one embodiment, the microwave radiation 140a within the reaction zone 104 lowers the effective activation energy required for a chemical reaction, such as the selective conversion of the precursor material 132a to the product 134a. For example, the microwave radiation 140a can act locally on a microscopic scale by exciting electrons of a group of specific atoms in contrast to global heating of the entire cavity 110 of the vessel 102 which raises a bulk temperature of all materials (e.g., plasma forming material 130a, precursor material 132a, vessel boundary (102a, plasma promoter material 136a, etc.) within the cavity 110. In one embodiment, the micro-plasma can act locally on a microscopic scale by exciting electrons of a group of specific atoms. Raising the temperature of all materials within the cavity 110 of the vessel 102 may utilize more energy than the effective activation energy for the conversion of the precursor material 132a into the product 134a.
Accordingly, utilizing the non-thermal plasma 150 (including the micro-plasma) enables localized heating and/or energy transfer, which results in a decrease in the energy requirements to selectively convert the precursor material 132a to the product 134a.
100751 After the plasma forming material 130a, the unconverted precursor material 132a, and product 134a are subject to microwave radiation 140a below their respective dielectric strengths, the non-thermal plasma 150 is extinguished (e.g., the non-thermal plasma 150 transitions to non-ionized or minimally ionized state) The extinguished non-thermal plasma 150, remainder of the plasma forming material 130a, unconverted precursor material 132a, partially converted precursor material 132a, and product 134a egress from the reaction zone 104 into the third conduit 124 as components of the stream 134. In one embodiment, the bulk temperature of the stream 134 is between 350 and 3000 degrees Kelvin and more preferably between 500 and 1500 degrees Kelvin. In one embodiment, the bulk temperature of the stream 134 is obtained prior to cooling of the stream 134. In one embodiment, a residence time of the reactants within the reaction zone 104 is between 15 milliseconds and 30 seconds. In one embodiment, at least a portion and/or component of the Date Recue/Date Received 2021-10-01 stream 134 are returned to the reaction zone 104 through a fourth conduit (not shown) for recycling. The fourth conduit (not shown) is operatively coupled to the third conduit 126 and at least one of the first conduit 120 and second conduit 122. Accordingly, the stream 134 comprises effluent egressing from the reaction zone 104.
[0076] The third conduit 124 is operatively coupled to a container 112 to collect the product 134a. The container 112 may be any known or conceivable material capable of withstanding heat, pressure(s), and the chemical environment(s) associated with the product 134a. For example, the container 112 may be constructed of, but is not limited to ceramics, and metals or metal alloys, such as brass, copper, steel, nickel, stainless steel, titanium, and aluminum. In one embodiment, the vessel 102 is oriented such that particles (e.g., solids, liquids of product 134a, etc.) free-fall through the third conduit 124 (e.g., down-flow). In one embodiment, the vessel 102 is oriented such that particles (e.g., solids, liquids of products 134a, etc.) require an applied force to exit in stream 134 in the third conduit 124 (e.g., up-flow). In one embodiment, the vessel 102 is oriented for a horizontal flow.
Accordingly, the container 112 is configured to receive the product 134a from the third conduit 124.
100771 As shown in FIG. 1B, in one embodiment, the vessel 102 may be configured for counter flow of at least two of the precursor material 132a, plasma forming material 130a, and/or plasma promoter material 136a. Accordingly, the container 112 is configured to receive the product 134a from the third conduit 124.
[0078] In one embodiment, the plasma forming material 130a and/or precursor material 132a may include an additive such as, but are not limited to, carbon black, coal, biochar, biomass, graphite, coke, structured carbon, carbon dioxide, carbon monoxide, and hydrogen The additive may accelerate the conversion of the precursor material to the product. In one embodiment, the additive is exposed to the microwave radiation 140a and/or the non-thermal plasma 150. In one embodiment, the additive is upgraded to a third material responsive to the exposure. In one embodiment, the upgrading may change the chemical, physical, and/or structural properties of the additive. For example, conductivity of the additive can be increased through re-ordering and/or functionalization of the additive's surface or bulk structure (e.g., carbon black may be upgraded to conductive carbon black).
In one embodiment, the additive's surface area and/or porosity may be altered (carbon to activated carbon). In one embodiment, graphite may be upgraded to, but not limited to, a Date Recue/Date Received 2021-10-01 graphene sheet. In one embodiment, the additive increases conversion of the precursor material 132a to product 134a. Accordingly, an additive may be added to the system for accelerated and/or increased conversion of the precursor material 132a and/or generation of a third material.
[0079] Referring to FIG. 2, a block diagram 200 is provided illustrating an alternate system for processing a precursor material into a product utilizing non-thermal micro-plasma and streamers. As shown, a vessel 202 is provided with multiple conduits configured to control ingress and egress of materials to and from a reaction zone 204 within a cavity 210 of the vessel 202. For example, a first conduit 220 and a second conduit 222 are provided in communication with a first side (206) of the vessel 202. The first and second conduits, 220 and 222, control and/or facilitate ingress of material(s) to the cavity 210 of vessel 202, including ingress of material(s) to the reaction zone 204. The vessel is provided with a vessel boundary 202a (e.g., walls) to support and/or maintain the reaction zone 204.
Namely, the first conduit 220 is operatively coupled to a first material source 230, and the first conduit 220 controls and/or facilitates ingress of a plasma forming material 230a provided by the first material source 230 to the reaction zone 204. Similarly, the second conduit 222 is operatively coupled to a second material source 232, and the second conduit 222 controls and/or facilitates ingress of a precursor material 232a provided by the second material source 232 to the reaction zone 204. At least one of the first conduit 220 and the second conduit 222 is operatively coupled to a third material source 236.
Accordingly, a plurality of conduits control ingress of materials to the reaction zone 204.
[0080] The plasma forming material 230a, precursor material 232a, and plasma promoter material 236a enter the reaction zone 204 and are subjected to microwave radiation 240a from radiation source 240. A non-thermal micro-plasma 250 is generated from at least one of the plasma forming material 230a, precursor material 232a, and plasma promoter material 236a. For example, the plasma forming material 230a becomes locally ionized proximal to and/or between first and second particles, 236ai and 236a2, respectively, in the form of a micro-plasma 250a as shown in magnified view 204a of the reaction zone 204.
[0081] A plasma in the form of a streamer discharge 250c, hereinafter referred to as a streamer, may also be generated within the reaction zone 204. For example, upon subjecting the plasma forming material 230a to the microwave radiation 240a and/or non-thermal plasma 250 which meets or exceeds the dielectric strength of the plasma forming material 230a, a valence electron is activated and/or excited from a first atom and/or molecule in the plasma forming material 230a. Upon excitation, the valence electron is removed from the Date Recue/Date Received 2021-10-01 first atom and/or molecule within the plasma forming material 230a and accelerated in a select direction based on a first electric field 214 generated by the microwave radiation 240a within the vessel 202. The accelerated electron strikes a second atom and/or molecule within the plasma forming material 230a causing removal of an electron from the second atom and/or molecule. The electron removal process progresses through the reaction zone 204 in this manner and results in an electron avalanche. The electrons within the electron avalanche have a third electron temperature.
100821 The electron avalanche comprises an ionized head region which is proximal to the direction of propagation of the electron avalanche and proximal to an adjacently positioned tail region. A space charge is produced by the electron avalanche causing a distortion of a second electric field 216 within the electron avalanche such that free electrons move towards the ionized head region, thereby increasing the strength of the second electric field 216 within the electron avalanche. The increase in the strength of the second electric field 216 facilitates additional electron avalanches to cumulate in the ionized head region causing the quantity of free electrons in the ionized head region to increase, which increases the strength of the second electric field 216. As the electron avalanche propagates, the positive ions (e.g., the atoms and/or molecules that have at least one electron removed) are left in the tail region of the electron avalanche. The tail region progresses through the reaction zone 204 slower than the ionized head region progresses through the reaction zone 204. An increase in free electrons in the ionized head region causes the first electric field 214 inside of the vessel 202 to increase in strength.
100831 As the electron avalanche progresses through the reaction zone 204 and the first electrical field 214 within the vessel 202 increases to a threshold charge, the ionized head region begins to decelerate and the electron temperature of the ionization head region decreases to a fourth electron temperature. In one embodiment, the fourth electron temperature is less than the third electron temperature. Following the deceleration, the electron avalanche transitions into a streamer 250c. In one embodiment, the streamer 250c is a type of non-thermal plasma with an excess of free electrons Similarly, in one embodiment, the streamer 250c has a longitudinal size that exceeds its transverse radius. A
distortion of the sizing of the streamer 250c results in a radiation intensity (e.g., degree of ionization, electron temperature, etc.) in the longitudinal direction of the streamer 250c that is higher than the radiation intensity in the radial direction of the streamer. In one embodiment, the longitudinal direction of the streamer 250c is relatively parallel to the flow Date Recue/Date Received 2021-10-01 direction 244 within the reaction zone 204. In one embodiment, the radial direction of the streamer 250c is relatively perpendicular to the flow direction 244.
[0084] Upon transition of the electron avalanche to the streamer 250c, the electron temperature within the streamer 250c continues to decrease to a fifth electron temperature.
In one embodiment, the fifth electron temperature is less than the fourth electron temperature. In one embodiment, the fifth electron temperature is between 800 and 6,000 degrees Kelvin, more preferably between 900 and 3,000 degrees Kelvin, and more preferably between 1,000 and 2,500 degrees Kelvin.
[0085] Additionally, due to the increase of strength in the first and second electrical fields, 214 and 216, respectively, additional electron avalanche(s) are initiated resulting in an additional streamer(s) 250a and/or micro-plasma(s) 250a. The additional electron avalanches may be negative charge directed (e.g., propagating towards a negative charge) and/or positively charge directed (e.g., propagating towards a positive charge). Accordingly, the micro-plasma 250a and/or streamers 250c may initiated additional micro-plasma and/or streamers.
[0086] The streamers 250c within reaction zone 204 are transient and dynamically changing. In one embodiment, any single streamer 250c is only present for a short period of time (e.g., less than 1 second). In one embodiment, the non-thermal plasma 250 has a non-uniform radiation intensity (e.g., degree of ionization, electron temperature, etc.) within the reaction zone 204. For example, there is an area(s) of high radiation intensity 252a (e.g., the streamers 250c and/or micro-plasma 250a), and an area(s) of low radiation intensity 252b (e.g., absence of streamers 250c and/or micro-plasma 250a). In one embodiment, the area(s) of high radiation intensity 252a is at the fifth electron temperature while the area(s) of low radiation intensity 252b is at a sixth electron temperature. In one embodiment, the sixth electron temperature is lower than the fifth electron temperature.
Accordingly, the non-thermal plasma 250 may be constantly and/or dynamically changing within reaction zone [0087] In one embodiment, the streamers 250a are primarily formed from the plasma forming material 230a. For example, on a molar basis, the streamers 250c are comprised of at least 50 percent plasma foiming material 230a, in another embodiment, the streamers 250c are comprised of at least 75 percent plasma forming material 230a ions and electrons, and in another embodiment the streamers 250c are comprised of at least 90 percent plasma forming material 130a ions and electrons. The streamers 250c initiate and/or continue selective conversion of the precursor material 232a to the product 234a. For example, the Date Recue/Date Received 2021-10-01 streamers 250c may act as an energy transfer catalyst activating the precursor material 232a.
The ions and electrons within the streamers 250c collide with the precursor material 232a.
The collisions result in energy transfer sufficient to promote cleavage of a bond (e.g., hydrogen atom to a carbon atom bond) of the precursor material 232a. For example, if the precursor material 232a is methane, the H3C-H bond is cleaved by the collisions.
[0088] Following interaction with the non-thermal plasma 250, the precursor material 232a, plasma forming material 230a, micro-plasma 250a, and/or streamers 250c form a convergence point 250d within the non-thermal plasma 250. At the convergence point 250d, the non-thermal plasma 250 dynamically changes composition. For example, the micro-plasma 250a and/or streamers 250c formed from the plasma forming material 230a converge, and in one embodiment, begin to extinguish (e.g., become less ionized). In one embodiment, the precursor material 232a receives a threshold amount of energy from the collision(s) with the ions and electrons within the non-thermal plasma 250 and/or receives a threshold amount of energy from the microwave radiation 240a wherein the precursor material 232a is at least partially ionized (e.g., greater than 0 percent to 100 percent). After receiving the threshold amount of energy, the precursor material 232a selectively converts into a non-thermal plasma 250c within the convergence point 250d. In one embodiment, the non-thermal plasma 250c has a C2 species temperature range of 1,500 to 5,500 degrees Kelvin, and in one embodiment, a C2 species temperature range of 2,000 to 3,500 degrees Kelvin. In one embodiment, the radiation intensity of the non-thermal plasma 250 is more uniform at the convergence point 250d than at the streamers 250c and/or micro-plasma 250a. Accordingly, the non-thermal plasma 250 changes composition along a distance of the reaction zone 204 [0088.1] Similar to FIG. 1B above, a third conduit 224 is provided in communication with a second side (208) of the vessel 202. The third conduit 224 is operatively coupled to a container 212 to collect the product 234a. Each conduit 220, 222, and 224 is enclosed within a fixed boundary (e.g. walls). For example, the first conduit 120 is shown with a first boundary 220a, the second conduit 222 is shown with a second boundary 222a, and the third conduit 224 is shown with a third boundary 224a. Accordingly, the materials of boundaries, 120a, 122a, and 124a, are capable of supporting transport of the reactants and the stream 134 within first, second, and third conduits, 120, 122, and 124, respectively.
[0089] Referring to FIG. 3A, a block diagram 300 is provided illustrating a flow configuration for processing the precursor material into the product utilizing the non-thermal plasma. As shown, the vessel 302 is provided with multiple conduits configured in a flow configuration, referred to herein as configurationA. The conduits control ingress and Date Recue/Date Received 2021-10-01 egress of materials to and from a reaction zone 304 within a cavity 310 of vessel 302. For example, a first conduit 320 and a second conduit 322 are provided in communication with a first side 306 of the vessel 302. The first and second conduits, 320 and 322, control and/or facilitate ingress of material(s) to the cavity 310 of vessel 302, including ingress of material(s) to the reaction zone 304. Namely, in flow configurationA, the first conduit 320 is operatively coupled to a first material source 330, and the first conduit 320 controls and/or facilitates ingress of a plasma forming material 330a provided by the first material source 27a Date Recue/Date Received 2021-10-01 330 to the reaction zone 304. Similarly, in flow configurationA, the second conduit 322 is operatively coupled to a second material source 332, and the second conduit 322 controls and/or facilitates ingress of a precursor material 332a provided by the second material source 332 to the reaction zone 304. In one embodiment, the first and second conduits, 320 and 322 are configured in flow configurationB wherein the first and second material sources 330 and 332 are reversed. For example, in flow configurationn, the first material source 330 provides the plasma forming material 330a to the second conduit 320 and the second material source 332 provides the precursor material 332a to the first conduit 322.
Accordingly, the first and second conduits, 320 and 322, respectively, control ingress of materials to the reaction zone 304 in different flow configurations.
[0090] As shown, the first conduit 320 is positioned within the second conduit 322. The positioning includes forming an annulus 322c between a first surface 320b of the first boundary 320a and a second surface 322b of the second boundary 322a. In one embodiment, the first conduit 320 is positioned concentrically with respect to the second conduit 322. The material flow through the second conduit 322 passes through the annulus 322c. For example, the precursor material 332a received from second material source 332, in flow configurationA, flows through the annulus 322c in the second conduit 322 into the reaction zone 304. The plasma forming material 330a received from the first material source 330a, in flow configurationA, flows through a cavity 320c within the first conduit 320 into the reaction zone 304 Accordingly, the positioning of the first and second conduits, 320 and 322, respectively, directs the material flow from the second conduit 322 to encompass the material flow from the first conduit.
[0091] In one embodiment, a fifth conduit 328 is positioned within the cavity 310, with the fifth conduit 328 effectively extending through the reaction zone 304. The first and second conduits 320 and 322 are positioned in communication with the fifth conduit 328. In one embodiment, the fifth conduit 328 is an extension of the second conduit 322. The fifth conduit 328 receives the plasma forming material 330a and the precursor material 332a from the first and second conduits, 320 and 322, respectively. The fifth conduit 328 facilitates traversal of the reactants and any product(s), such as product 334a, through the reaction zone 304 into stream 324 of the third conduit 324. As shown, the fifth conduit 328 has fifth boundary 328a, which may be constructed of, but not limited to, a microwave radiation transparent material. The material of the fifth boundary 328a may be any known or conceivable material capable of withstanding the heat, pressure(s), and chemical environmental associated with transporting materials within the respective conduits and/or Date Recue/Date Received 2021-10-01 enabling generation of the non-thermal plasma 350. For example, the fifth boundary 328a may be, but are not limited to ceramics, and glasses. In one embodiment, the reaction zone 304 is limited to the fifth boundary 328a of the fifth conduit 328.
Accordingly, the fifth conduit 328 controls and facilitates the traversal of the reactants and product(s) through the reaction zone 304 into the third conduit 324. Similar to FIG. 2 above, a plasma in the form of a streamer discharge 350a, hereinafter referred to as a streamer, may also be generated within the reaction zone 304. Following interaction with the non-thermal plasma 350, the precursor material 332a, plasma forming material 330a, micro-plasma 350, and/or streamers 350a form a convergence point 350b within the non-thermal plasma 350.
[0092] In one embodiment, the precursor material 332a has a higher dielectric strength than the plasma forming gas 330a. In flow configurationA, the precursor material 332a encompasses the plasma forming material 330a through at least a portion of the reaction zone 304. The precursor material 330a may act as an energy shield (e.g., shielding material) protecting the vessel boundary 302a of vessel, and in one embodiment fifth boundary 328a of the fifth conduit 328a, from being directly exposed to the non-thermal plasma 350. The precursor material 330a absorbs the heat and/or energy escaping from the non-thermal plasma 350 and limits the heat and/or energy that is in communication with the vessel boundary 302a and/or 328a. In one embodiment, flow configurationA enables generation of the non-thermal plasma 350 in a position distal from the vessel boundary 302a wherein the highest temperature of the reaction zone 304 is not in communication with the vessel boundary 302a of the vessel 302. Positioning of the non-thermal plasma 350 distal from the vessel boundary 302a and/or the shielding effect of the precursor material 332a limits carbon formation on vessel boundary 302a and/or 328a. Carbon formed on the vessel boundary 302a and/or 328a may absorb microwave energy 340a before the microwave energy 340a can facilitate the selective conversion of the precursor material 324a thus decreasing the efficiency of the precursor processing system. In one embodiment, flow configurationA operates more efficiently (e.g., less energy and less routine maintenance) than flow configurationu due the limited carbon formation. Accordingly, the positioning of the first and second conduits, 320 and 322, enhances reactor efficiency and mitigates the need for an additional dedicated shielding gas to protect the vessel boundary 302a of the vessel 302 from carbon build up Date Recue/Date Received 2021-10-01 [0093] The exposure of the precursor material 332a to the microwave radiation 340a may be initiated prior to interacting with the plasma forming material 330a and/or non-thermal plasma 350. To support the initiation, the second conduit 322 extends a first distance (Xi) into the reaction zone 304 creating a first area 322d within the second conduit 322 that is within the reaction zone 304. In flow configurationA, while the precursor material 332a is within the first area 322d, the precursor material 332a is separate from the plasma forming material 330a. In one embodiment, the second conduit 322 has a second 29a Date Recue/Date Received 2021-10-01 boundary 322a comprised of a microwave transparent material. Thus, since the first area 304 is within the reaction zone 304, the precursor material 332a is subjected to microwave radiation 340a from radiation source 340 within the first area 322d. The first distance (Xi) may be configured to adjust the quantity of microwave radiation 340a the precursor material 332a is subjected to before exiting the second conduit 322 and interacting with the non-thermal plasma 350 and/or plasma forming material 330a. Accordingly, in flow configurationA, the first area 322d subjects the precursor material 332a to microwave energy 340a prior to the precursor material exiting the second conduit 322.
[0094] In the first area 322d of flow configurationA, the molecules and/or atoms of the precursor material 332a are excited rotationally and/or vibrationally through collisions with other molecules and/or atoms, non-thermal plasma, electrons, and/or ions generated by exposure to the microwave radiation 340a. In one embodiment, excitation of the precursor material 332a is at an energy level that is not sufficient to immediately rupture the bonds of the molecules and/or atoms within the precursor material 332a and generate ionic or free-radical states (e.g., generate ions and/or a plasma). In one embodiment, the microwave radiation 340a within the first area 322d indirectly excites energy states of atoms and/or molecules which lowers the effective activation energy required for a desired chemical reaction, such as a selective conversion of the precursor material 332a to the product 324a.
In one embodiment, the excited precursor material 332a interacts with itself, intermediate product(s), and/or a non-excited precursor material within the first area 322d to form higher hydrocarbon materials (e.g., a hydrocarbon having more carbon atoms than the original precursor material 332a). Subjecting the precursor material 332a to microwave radiation prior to exiting the second conduit 322 may enable a higher conversion rate of the precursor material 332a to product 324a and/or limit carbon build up on vessel boundary 302a of vessel 302. Accordingly, the precursor material 332a is subjected to microwave radiation 340a prior to interacting with plasma forming material 330a and/or non-thermal plasma [0095] Exposure of the plasma forming material 330a to the microwave radiation 340a may be initiated prior to interacting with the precursor material 332a. To support the initiation of the plasma forming material 330a, the first conduit 320 extends a second distance (X2) into the reaction zone 304 creating a second area 320d within the first conduit 320 that is within the reaction zone 304. In one embodiment, the first conduit 320 has a first boundary 320a comprised of a microwave transparent material. Thus, since the second area 320d is within the reaction zone 304, the plasma forming material 330a is subjected to Date Recue/Date Received 2021-10-01 microwave radiation 340a in the second area 320d. The second distance (X2) may be configured to adjust the quantity of microwave radiation 340a the plasma forming material 330a is subjected to before exiting the first conduit 320 and interacting with the precursor material 332a. Accordingly, in flow configurationA, the second area 320d subjects the plasma forming material 330a to microwave energy 340a prior to the plasma forming material 330a exiting the first conduit 320.
[0096] In the second area 320d, the molecules and/or atoms of the plasma forming material 332a are excited rotationally and/or vibrationally by collisions of ions, electrons or other species generated by exposure to the microwave radiation 340a. In one embodiment, the excitation of the plasma forming material 330a is at an energy level that is not sufficient to immediately rupture the bonds of the molecules and/or atoms within the plasma forming material 330a and generate ionic or free-radical states (e.g., generate ions and/or a plasma).
In one embodiment, the microwave radiation 340a within the second area 320d lowers the effective activation energy required for generating a plasma from the plasma forming material 330a. Subjecting the plasma forming material 330a to microwave radiation 340a prior to mixing with the precursor material 332a may enable the non-thermal plasma 350 to be generated more efficiently since collisions between electrons removed from the plasma forming material 330a and the molecules and/or atoms of the precursor material 332a are limited. Thus, the free electrons within the plasma forming material 330a may continue to progress into electrons avalanches with other atoms and/or molecules of the plasma foitning material 330a while avoiding potential quenching from atoms and/or molecules from the precursor material 332a. Accordingly, the plasma forming material 330a is subjected to microwave radiation 340a prior to interacting with precursor material 332a.
[0097] The reactants may be subjected to microwave energy prior to interaction with one another in a variety of configurations. For example, in FIG. 1A, the plasma forming material 130a and/or precursor material 132a may be subjected to microwave energy 140a prior to interacting with one another. As shown in FIG. 1A, the first conduit 120 is not positioned within the second conduit 122. However, the first conduit 120 is positioned at a first angle (cti) with respect to the second conduit 122; the second conduit 122 is positioned at a second angle (a2) with respect to the first conduit 120; and the first conduit 120 is positioned a distance (X3) from the second conduit 122. The first and second angles, (cu) and (a2), and distance (X.3) may affect a direction that the respective reactants flow and thereby the residence time of the reactants within the reaction zone 104 prior to interacting with one another. For example, the second angle (c2) and distance (X3) affect a first travel Date Recue/Date Received 2021-10-01 distance the precursor material 132a has to traverse within the reaction zone 104 after exiting the second conduit 122 and prior to interacting with plasma forming material 130a.
Similarly, the first angle (cti) and distance (X3) affect a second travel distance the plasma forming material 130a has to traverse within the reaction zone 104 after exiting the first conduit 120 and prior to interacting with precursor material 132a. The residence time of the reactants within the reaction zone 104 prior to communicating with and/or otherwise interacting with one another is based on the first and second travel distances, diffusive properties of the reactants, and velocity of the respective reactants.
Accordingly, the plasma forming material 130a and/or precursor material 132a may be subjected to microwave energy 140a prior to interacting with one another in a variety of different vessel configurations.
[0098] Referring to FIG. 3B, a block diagram 300 is provided illustrating a flow configuration for processing the precursor material into the product utilizing the non-thermal plasma along with a plasma promoter. As shown, the vessel 302 is provided with multiple conduits configured in a flow configuration, referred to herein as configurationA.
The conduits control ingress and egress of materials to and from a reaction zone 304 within a cavity 310 of vessel 302. For example, a first conduit 320 and a second conduit 322 are provided in communication with a first side 306 of the vessel 302. The first and second conduits, 320 and 322, control and/or facilitate ingress of material(s) to the cavity 310 of vessel 302, including ingress of material(s) to the reaction zone 304. Namely, in flow configurationA, the first conduit 320 is operatively coupled to a first material source 330, and the first conduit 320 controls and/or facilitates ingress of a plasma forming material 330a provided by the first material source 330 to the reaction zone 304.
Similarly, in flow configurationA, the second conduit 322 is operatively coupled to a second material source 332, and the second conduit 322 controls and/or facilitates ingress of a precursor material 332a provided by the second material source 332 to the reaction zone 304. In one embodiment, the first and second conduits, 320 and 322 are configured in flow configurationB wherein the first and second material sources 330 and 332 are reversed. For example, in flow configurationB, the first material source 330 provides the plasma forming material 330a to the second conduit 320 and the second material source 332 provides the precursor material 332a to the first conduit 322. Accordingly, the first and second conduits, 320 and 322, respectively, control ingress of materials to the reaction zone 304 in different flow configurations.

Date Recue/Date Received 2021-10-01 [0099] As shown, the first conduit 320 is positioned within the second conduit 322. The positioning includes forming an annulus 322c between a first boundary 320b of the first conduit 320 and a second boundary 322b of the second conduit 322. In one embodiment, the first conduit 320 is positioned concentrically with respect to the second conduit 322. The material flow through the second conduit 322 passes through the annulus 322c.
For example, the precursor material 332a received from second material source 332, in flow configurationA, flows through the annulus 322c in the second conduit 322 into the reaction zone 304. The plasma forming material 330a received from the first material source 330a, in flow configurationA, flows through a cavity 320c within the first conduit 320 into the reaction zone 304. Accordingly, the positioning of the first and second conduits, 320 and 322, respectively, directs the material flow from the second conduit 322 to encompass the material flow from the first conduit.
[00100] In one embodiment, a fifth conduit 328 is positioned within the cavity 310, with the fifth conduit 328 effectively extending through the reaction zone 304. The first and second conduits 320 and 322 are positioned in communication with the fifth conduit 328. In one embodiment, the fifth conduit 328 is an extension of the second conduit 322. The fifth conduit 328 receives the plasma forming material 330a, the precursor material 332a, and the plasma promoter material 336a (from material source 336) from the first and second conduits, 320 and 322, respectively. The fifth conduit 328 facilitates traversal of the reactants and any product(s), such as product 334a, through the reaction zone 304 into stream 334 of the third conduit 324 in fluid communication with the second side 308 of the vessel 302. As shown, the fifth conduit 328 has fifth boundary 328a, which may be constructed of, but not limited to, a microwave radiation transparent material. The material of the fifth boundary 328a may be any known or conceivable material capable of withstanding the heat, pressure(s), and chemical environmental associated with transporting materials within the respective conduits and/or enabling generation of the non-thermal micro-plasma 350. For example, the fifth boundary 328a may be, but is not limited to ceramics, and glasses. In one embodiment, the reaction zone 304 is limited to the fifth boundary 328a of the fifth conduit 328. Accordingly, the fifth conduit 328 controls and facilitates the traversal of the reactants and product(s) through the reaction zone 304 into the third conduit 324.

Date Recue/Date Received 2021-10-01 [00101] In one embodiment, the precursor material 332a has a higher dielectric strength than the plasma forming gas 330a. In flow configurationA, the precursor material 332a and plasma promoter material 336a encompasses the plasma forming material 330a through at least a portion of the reaction zone 304. The precursor material 330a and plasma promoter material 336a may act as an energy shield (e.g., shielding material) protecting the vessel 33a Date Recue/Date Received 2021-10-01 boundary 302a of vessel, and in one embodiment fifth boundary 328a of the fifth conduit 328a, from being directly exposed to the non-thermal plasma 350. The precursor material 330a absorbs the heat and/or energy escaping from the non-thermal plasma 350 and limits the heat and/or energy that is in communication with the vessel and fifth boundaries 302a and/or 328a, respectively. In one embodiment, flow configurationA enables generation of the non-thermal micro-plasma 350 in a position distal from the vessel boundary 302a wherein the highest temperature of the reaction zone 304 is not in communication with the vessel boundary 302a of the vessel 302. Positioning of the non-thermal plasma 350 distal from the vessel boundary 302a and/or the shielding effect of the precursor material 332a limits carbon formation on vessel and fifth boundaries, 302a and/or 328a, respectively.
Carbon formed on the vessel and fifth boundaries 302a and/or 328a, respectively, may absorb microwave energy 340a before the microwave energy 340a can facilitate the selective conversion of the precursor material 334a thus decreasing the efficiency of the precursor processing system. In one embodiment, flow configurationA operates more efficiently (e.g., less energy and less routine maintenance) than flow configurationB due the limited carbon formation. Accordingly, the positioning of the first and second conduits, 320 and 322, enhances reactor efficiency and mitigates the need for an additional dedicated shielding gas to protect the vessel boundary 302a of the vessel 302 from carbon build up.
[00102] The exposure of the precursor material 332a to the microwave radiation 340a may be initiated prior to interacting with the plasma forming material 330a and/or non-thermal micro-plasma 350. To support the initiation, the second conduit 322 extends a first distance (Xi) into the reaction zone 304 creating a first area 322d within the second conduit 322 that is within the reaction zone 304. In flow configurationA, while the precursor material 332a and/or plasma promoter material 336a is within the first area 322d, the precursor material 332a is separate from the plasma forming material 330a. In one embodiment, the second conduit 322 has a second boundary 322a comprised of a microwave transparent material. Thus, since the first area 304 is within the reaction zone 304, the precursor material 332a is subjected to microwave radiation 340a from radiation source 340 within the first area 322d. The first distance (Xi) may be configured to adjust the quantity of microwave radiation 340a the precursor material 332a is subjected to before exiting the second conduit 322 and interacting with the non-thermal micro-plasma 350 and/or plasma forming material 330a. Accordingly, in flow configurationA, the first area 322d subjects the precursor material 332a to microwave energy 340a prior to the precursor material exiting the second conduit 322.

Date Recue/Date Received 2021-10-01 [00103] In the first area 322d of flow configurationA, the molecules and/or atoms of the precursor material 332a are excited rotationally and/or vibrationally through collisions with other molecules and/or atoms, non-thermal plasma, electrons, and/or ions generated by exposure to the microwave radiation 340a. In one embodiment, excitation of the precursor material 332a is at an energy level that is not sufficient to immediately rupture the bonds of the molecules and/or atoms within the precursor material 332a and generate ionic or free-radical states (e.g., generate ions and/or a plasma). In one embodiment, the microwave radiation 340a within the first area 322d indirectly excites energy states of atoms and/or molecules which lowers the effective activation energy required for a desired chemical reaction, such as a selective conversion of the precursor material 332a to the product 334a.
In one embodiment, the excited precursor material 332a interacts with itself, intermediate product(s), and/or a non-excited precursor material within the first area 322d to form higher hydrocarbon materials (e.g., a hydrocarbon having more carbon atoms than the original precursor material 332a). Subjecting the precursor material 332a to microwave radiation prior to exiting the second conduit 322 may enable a higher conversion rate of the precursor material 332a to product 334a and/or limit carbon build up on vessel boundary 302a of vessel 302. Accordingly, the precursor material 332a is subjected to microwave radiation 340a prior to interacting with plasma forming material 330a and/or non-thermal plasma 350.
[00104] Exposure of the plasma forming material 330a to the microwave radiation 340a may be initiated prior to interacting with the precursor material 332a. To support the initiation of the plasma forming material 330a, the first conduit 320 extends a second distance (X2) into the reaction zone 304 creating a second area 320d within the first conduit 320 that is within the reaction zone 304. In one embodiment, the first conduit 320 has a first boundary 320a comprised of a microwave transparent material. Thus, since the second area 320d is within the reaction zone 304, the plasma forming material 330a is subjected to microwave radiation 340a in the second area 320d. The second distance (X2) may be configured to adjust the quantity of microwave radiation 340a the plasma forming material 330a is subjected to before exiting the first conduit 320 and interacting with the precursor material 332a. Accordingly, in flow configurationA, the second area 320d subjects the plasma forming material 330a to microwave energy 340a prior to the plasma forming material 330a exiting the first conduit 320.
[00105] In the second area 320d, the molecules and/or atoms of the plasma forming material 332a are excited rotationally and/or vibrationally by collisions of ions, electrons or Date Recue/Date Received 2021-10-01 other species generated by exposure to the microwave radiation 340a. In one embodiment, the excitation of the plasma forming material 330a is at an energy level that is not sufficient to immediately rupture the bonds of the molecules and/or atoms within the plasma forming material 330a and generate ionic or free-radical states (e.g., generate ions and/or a plasma).
In one embodiment, the microwave radiation 340a within the second area 320d lowers the effective activation energy required for generating a plasma from the plasma forming material 330a. Subjecting the plasma forming material 330a to microwave radiation 340a prior to mixing with the precursor material 332a may enable the non-thermal plasma 350 to be generated more efficiently since collisions between electrons removed from the plasma forming material 330a and the molecules and/or atoms of the precursor material 332a are limited. Thus, the free electrons within the plasma forming material 330a may continue to progress into electrons avalanches with other atoms and/or molecules of the plasma foi ming material 330a while avoiding potential quenching from atoms and/or molecules from the precursor material 332a. Accordingly, the plasma forming material 330a is subjected to microwave radiation 340a prior to interacting with precursor material 332a.
[00106] The reactants may be subjected to microwave energy prior to interaction with one another in a variety of configurations. For example, in FIG. 1B, the plasma Ruining material 130a, precursor material 132a, and/or plasma promoter material 136a may be subjected to microwave energy 140a prior to interacting with one another. As shown in FIG. 1, the first conduit 120 is not positioned within the second conduit 122.
However, the first conduit 120 is positioned at a first angle (cti) with respect to the second conduit 122;
the second conduit 122 is positioned at a second angle (co) with respect to the first conduit 120; and the first conduit 120 is positioned a distance (X3) from the second conduit 122.
The first and second angles, (au) and (a2), and distance (X3) may affect a direction that the respective reactants flow and thereby the residence time of the reactants within the reaction zone 104 prior to interacting with one another. For example, the second angle (co) and distance (X3) affect a first travel distance the precursor material 132a has to traverse within the reaction zone 104 after exiting the second conduit 122 and prior to interacting with plasma forming material 130a. Similarly, the first angle (c4) and distance (X3) affect a second travel distance the plasma forming material 130a has to traverse within the reaction zone 104 after exiting the first conduit 120 and prior to interacting with precursor material 132a. The residence time of the reactants within the reaction zone 104 prior to communicating with and/or otherwise interacting with one another is based on the first and second travel distances, diffusive properties of the reactants, and velocity of the respective Date Recue/Date Received 2021-10-01 reactants. Accordingly, the plasma forming material 130a and/or precursor material 132a may be subjected to microwave energy 140a prior to interacting with one another in a variety of different vessel configurations.
[00107] Referring now to FIG. 4, a block diagram illustrating a system 400 for processing a precursor material into a product comprising graphitic materials utilizing the non-thermal plasma is shown. As shown in FIG. 4, the system 400 includes a plasma forming zone 402 and a reaction zone 404 coupled via an interface element 410.
In an embodiment, the interface element may be a plasma nozzle.
[00108] In an embodiment, the plasma forming zone 402 may include a radiation source 422 and a waveguide 423 that directs radiation from the radiation source 422 into a discharge tube 424. The radiation source 422 (e.g., a microwave generator) generates radio frequency (RF) radiation and/or microwave radiation, hereinafter referred to collectively as microwave radiation. The frequencies of the microwave radiation may be in the range from 36 megahertz (MHz) to 300 gigahertz (GHz), more preferably 40 MHz to 6 GHz, and most preferably 400 MHz to 3 GHz. For example, the microwave radiation frequency may be, but is not limited to, 896 MHz, 945 MHz and 2.45 GHz. The radiation source may be, but is not limited to, a magnetron. While FIG. 4 shows a waveguide 423, coaxial, direct, antenna, or other types of couplings between the radiation source 422 and the discharge tube 424 are within the scope of this disclosure. In one embodiment, there is a plurality of radiation sources. The plurality of radiation sources may be coupled to a single waveguide or a plurality of waveguides. Regardless of the coupling method, the microwave radiation generates and sustains a non-thermal plasma within the discharge tube 424 is at a concentration ranging from 400 watts (W) per liter to 20,000 kilowatts (kW) per liter, more preferably between 4 and 300 kW per liter, and most preferably between 400 and 200 kW
per liter. In one embodiment, the microwave radiation within the discharge tube 424 is at a concentration less than 2000 kW per liter, more preferably greater than 30 kW
per liter, and most preferably greater than 450 kW per liter. At a microwave radiation density within the discharge tube 424 of about 400 kilowatts per liter and about 200 kilowatts per liter (kW/L), the non-thermal plasma transitions from filamentary discharges to diffuse glow discharge.
[00109] Examples of a waveguide may include, without limitation, a waveguide surfatron, a surfatron, or a surfaguide. In an example embodiment, a 4.5-6 kW
microwave magnetron operating at 2.45 GHz may be used, and the microwave power applied maybe about 3kW to about 6kW.

Date Recue/Date Received 2021-10-01 [0100] In an embodiment, the discharge tube 424 may be inserted into the waveguide 423 at a perpendicular angle. The discharge tube 424 may be a made of quartz, borosilicate glass, alumina, sapphire, or another suitable dielectric material that promotes the generation and sustenance of a non-thermal plasma 425 when a plasma forming material from a plasma forming material source 430 passes through the discharge tube 424 in the presence of microwave radiation. The inner diameter of the discharge tube 424 may be about 4 mm to about 60 cm, about 4 cm to about 50 cm, about 40 cm to about 40 cm, about 20 cm to about 30 cm. The inner diameter of the discharge tube 424 may vary with the power and frequency of the microwave input; a preferable diameter at a given frequency f can be estimated as between 40% and 20% of ratio cif, where c is the speed of light in vacuum. In an embodiment, the inner diameter of the discharge tube 424 may be about 0.425" to about 0.8", more preferably about 0.6" to about 0.8", most preferably about 0.67".
In another embodiment, the inner diameter of the discharge tube 424 may be about 0.335"
to about 2.68", more preferably about 4.6" to about 2.444", most preferably about 4.8". The plasma forming material may comprise virtually any material that can be used to generate plasma, such as, but not limited to, the non-thermal plasma 425. For example, the plasma founing material may be, but is not limited to argon, hydrogen, helium, neon, krypton, xenon, carbon dioxide, nitrogen, synthesis gas, and water vapor (or water in the form of droplets, aerosols, or steam). It is understood that the plasma forming material may not be pure and may contain a variety of impurities as known in the art.
[0101] In certain embodiments, an ignitor mechanism may be used to initiate the generation of the non-thermal plasma 425. Alternatively and/or additionally, a plasma initiation mechanism may be used to initiate the generation of the non-thermal plasma 425.
An initiation mechanism comprised of a conductive material may be introduced coaxially or otherwise to the inside or end of the discharge tube to provide a source of free electrons and initiate the non-thermal plasma. In certain embodiments, initiation of non-thermal plasma within the discharge tube may be also be facilitated through other means such as reduction of gas pressure within the discharge tube below 4 bar or more preferably below 0.5 bar or most preferably below 0.4 bar with subsequent reintroduction of gas to return to operational pressure. In certain embodiments, available free electrons may be sufficient to initiate plasma without an initiation mechanism.
[0102] In an embodiment, gas temperature (i.e., temperature of the non-thermal plasma) at the outlet of the plasma forming zone is about 300 to about 2,000 C, and the electron density within the discharge tube is above the critical density.
Specifically, the Date Recue/Date Received 2021-10-01 temperature is about 400 to about 4,500 C, about 500 to about 4200 C, about 600 to about 4000 C, or about 300 to about 500 C. The electron density may be increased by increasing gas pressure, reducing gas flow rates, decreasing discharge tube diameter, or increasing the incident microwave power absorbed by the plasma and/or plasma-forming material.
[0103] In an embodiment, absorption of microwave energy promotes electron and ion impacts/collisions within but not limited to a portion of atoms and/or molecules of the plasma forming material which results in ionization of the portion of atoms and/or molecules of the plasma forming material. In one embodiment, the plasma forming material is at least partially ionized (e.g., greater than 0 percent to 400 percent) and converted to the non-thermal plasma 425. Elastic and inelastic collisions between species, such as but not limited to electrons, non-thermal plasma 425, ions, atoms and/or molecules of plasma forming material, radical species, and/or intermediate product(s) present in the discharge tube 424 results in energy transfer either directly or indirectly to the plasma forming material. Energy transfer can excite (and/or increase the energy level) vibrational, electronic, rotational, and translational energy state(s) of the atoms and/or molecules of the plasma forming. In one embodiment, transfer of energy to vibrational and electronic energy states is greater than transfer of energy to translational energy state within the non-thermal plasma 425. In one embodiment, the energy states of the non-thermal plasma are not in thermodynamic equilibrium such that the electron and/or vibrational temperature are greater than rotational, ion, and/or translation temperatures.
[0104] In one embodiment, upon subjecting the plasma forming material to the microwave radiation which meets or exceeds the dielectric strength of the plasma forming material, a valence electron is activated and/or excited from a first atom and/or molecule in the plasma forming material. Upon excitation, the valence electron is removed from the first atom and/or molecule within the plasma forming material and accelerated in a select direction based on a first electric field generated by the microwave radiation within the discharge tube 424 The accelerated electron strikes a second atom and/or molecule within the plasma forming material causing removal of an electron from the second atom and/or molecule. The electron removal process progresses through the discharge tube 424 in this manner and results in an electron avalanche. The electrons within the electron avalanche have a first electron temperature.
[0105] The electron avalanche comprises an ionized head region which is proximal to the direction of propagation of the electron avalanche and proximal to an adjacently positioned tail region. A space charge is produced by the electron avalanche causing a Date Recue/Date Received 2021-10-01 distortion of a second electric field within the electron avalanche such that free electrons move towards the ionized head region, thereby increasing the strength of the second electric field within the electron avalanche. The increase in the strength of the second electric field facilitates additional electron avalanches to cumulate in the ionized head region causing the quantity of free electrons in the ionized head region to increase, which increases the strength of the second electric field. As the electron avalanche propagates, the positive ions (e.g., the atoms and/or molecules that have at least one electron removed) are left in the tail region of the electron avalanche. The tail region progresses through the discharge tube 424 slower than the ionized head region progresses through the discharge tube 424. An increase in free electrons in the ionized head region causes the first electric field inside of the discharge tube 424 to increase in strength.
[0106] As the electron avalanche progresses through the discharge tube 424 and the first electrical field discharge tube 424 increases to a threshold charge, the ionized head region begins to decelerate and the electron temperature of the ionization head region decreases to a second electron temperature. In one embodiment, the second electron temperature is less than the first electron temperature. Following the deceleration, the electron avalanche transitions into a streamer discharge, hereinafter referred to as a streamer. In one embodiment, a streamer is a type of non-thermal plasma with an excess of free electrons. Similarly, in one embodiment, the streamer has a longitudinal size that exceeds its transverse radius. A distortion of the sizing of the streamer results in a radiation intensity (e.g., degree of ionization, electron temperature, etc.) in the longitudinal direction of the streamer that is higher than the radiation intensity in the radial direction of the streamer. In one embodiment, the longitudinal direction of the streamer is relatively parallel to the flow direction of plasma forming material within the discharge tube 424. In one embodiment, the radial direction of the streamer is relatively perpendicular to the direction of microwave power propagation.
101071 Upon transition of the electron avalanche to the streamer, the electron temperature within the streamer continues to decrease to a third electron temperature. In one embodiment, the third electron temperature is less than the second electron temperature. In one embodiment, the third electron temperature is between 800 and 6,000 degrees Kelvin, more preferably between 900 and 3,000 degrees Kelvin, and more preferably between 4,000 and 2,500 degrees Kelvin. In one embodiment, the third electron temperature is not subject to an increase in temperature after a threshold microwave radiation density is reached within the discharge tube 424. In one embodiment, the threshold microwave radiation density Date Recue/Date Received 2021-10-01 within the discharge tube 424 is 45 kW per liter, more preferably 9 kW per liter, and more preferably 4 kW per liter. It is understood that the threshold microwave radiation density may be dependent on the reactants introduced to the discharge tube 424 and/or configuration of the discharge tube 424, thus the threshold microwave radiation density may vary from the values illustrated. Additionally, due to the increase of strength in the first and second electrical fields, additional electron avalanche(s) are initiated resulting in additional streamers. The additional electron avalanches may be negative charge directed (e.g., propagating towards a negative charge) and/or positively charge directed (e.g., propagating towards a positive charge).
101081 The streamers within the discharge tube 424 may be transient and dynamically changing, and may transform to diffuse glow plasma at higher power densities.
In one embodiment, any single streamer is only present for a short period of time (e.g., less than 4 second). In one embodiment, the non-thermal plasma 425 has a non-uniform radiation intensity (e.g., degree of ionization, electron temperature, etc.) within the discharge tube 424. For example, there is an area(s) of high radiation intensity (e.g., the streamers), and an area(s) of low radiation intensity (e.g., absence of streamers). In one embodiment, the area(s) of high radiation intensity is at the third electron temperature while the area(s) of low radiation intensity is at fourth electron temperature. In one embodiment, the fourth electron temperature is lower than the third electron temperature.
Accordingly, the non-thermal plasma 425 may be constantly and/or dynamically changing within the discharge tube 424 101091 The non-thermal plasma 425, which may include streamers and/or diffuse glow plasma, generated in the discharge tube 424 may be transmitted to the reaction zone 404 via an interface element 410, with the microwave radiation. Optionally, microwaves may not be transmitted to the reaction zone 404. Specifically, a dense plasma head 425(a) of the non-thermal plasma 425 extends into the reaction zone 404. In an embodiment, the interface element 410 may be a conduit configured to propagate plasma into the reaction zone 404 in a reaction vessel 442. The interface element 410 may also act as a conduit for conducting and emitting microwave energy into reaction zone 404. Additionally, the dense plasma may serve as an antenna or conduit to transmit additional microwaves into the reaction zone 404. Additionally and/or alternatively, any unreacted plasma forming material may also be transmitted into the reaction zone 404. As used herein, "dense plasma head"
(or "dense plasma") is the plasma portion that has an electron density that is equal to or Date Recue/Date Received 2021-10-01 greater than the critical density and that is transmitted from the plasma forming zone 402 to the reaction zone 404.
[0110] In one embodiment, the reaction vessel 442 may be configured to accept microwave energy via the dense plasma head 425(a) through impedance matching or by other means. Alternatively, the reaction vessel 442 may be configured to reject microwave energy via the dense plasma head 425(a) through restriction of the dense plasma head inlet diameter to less than 40% of the electromagnetic wavelength used to generate the non-thermal plasma 425.
[0111] In an embodiment, the reaction zone 404 may be included within a reaction tube (not shown here) of a reaction vessel 442. Alternatively, the reaction tube may be absent.
Specifically, in the system shown herein, a reaction vessel 442 is provided to facilitate processing of the feedstock material. More specifically, the reaction vessel 442 is configured with a resonant cavity 440 and a reaction zone 404 within the cavity 440. In an embodiment, the resonant cavity 440 may have a size such that it is configured to resonate with a fundamental mode shape. For example, the resonant cavity may have size such that it is configured to resonate with a transverse magnetic (TM) mode shape (e.g., a uniaxial transverse magnetic mode shape TMO4n). Such transverse magnetic mode shape may promote microwave propagation into the resonant cavity and prevent microwave reflection caused by impedance mismatch. Since the plasma antenna operates in the coaxial mode shape, it can deliver energy to a fundamental mode shape with an axial electric field component.
[0112] The reaction zone 404 is configured to facilitate interaction of and/or mixing of various material(s) including the feedstock material in the presence of the dense plasma head 425(a) and/or the microwave radiation. As used herein, the term ``precursor" or 'feedstock" refers to a substance from which a product comprising a graphitic material is formed. Optionally, the reaction tube may be absent.
[0113] In an embodiment, the reaction zone 404 may receive a fluidized bed of feedstock material and/or a process gas from a feedstock source 445 and/or a process gas source 446, respectively, and the dense plasma head 425(a) of the non-thermal plasma 425 from the interface element 410. In an embodiment, the interface element 410 may also transmit microwave radiation in the reaction zone 404. Alternatively, the dense plasma head 425(a) may act as a conduit for the microwave radiation. In the presence of the dense plasma head 425(a) of the non-thermal plasma 425 and the microwave radiation, the non-thermal plasma 425 may grow to fill the cavity 440. In this manner, non-thermal plasma Date Recue/Date Received 2021-10-01 may be sustained and controlled without discharging to conductive walls of the reaction vessel 442. Furthermore, this method of generating plasma outside of the reaction zone allows the reaction to take place outside of the dielectric containment (i.e., the discharge tube) and may reduce or prevent deposition of reaction by-products with non-zero loss tangent onto dielectric materials near the reaction.
[0114] The size and/or location of the reaction zone 404 and/or non-thermal dense plasma head 425(a) may be dynamic. For example, in one embodiment, the reaction zone 404 may extend to the reaction vessel boundary. The reaction vessel boundary may be comprised of any known or conceivable material capable of withstanding the heat, pressure(s), and chemical environments associated with generating and/or sustaining the non-thermal plasma.
For example, the material of vessel boundary may be a microwave radiation opaque material (e.g., limits penetration of microwave radiation through the material). The microwave radiation opaque material may be, but is not limited to ceramics, carbon-based materials and composites, and metals or metal alloys, such as brass, copper, steel, nickel, stainless steel, titanium, and aluminum, and alloys and combinations thereof. The microwave radiation opaque materials may additionally be coated with high-conductivity materials, including but not limited to silver, gold, carbon materials including graphene, and combinations thereof. In one embodiment, the vessel boundary is constructed of a microwave radiation reflective material. In one embodiment, the vessel is operated at atmospheric pressure.
Accordingly, the vessel is configured to withstand the heat, pressure(s), and chemical environment(s) associated with processing the feedstock material.
[0115] In an embodiment, the feedstock material in the form of a fluidized bed may be introduced into a reaction tube 444 operably connected to the reaction vessel 442 in the reaction zone 404 at or near the interface element 410 (as shown in FIG. 4).
In such an embodiment, the feedstock material is subjected to the dense plasma head 425(a) and associated microwave radiation in the reaction zone 404.
[0116] Alternatively and/or additionally, as shown in FIG. 5, the system 500 includes the discharge tube 524 (including the interface element 510) may be positioned within a reaction tube 541 operably connected to the reaction vessel 542. The positioning includes forming an annulus (520) between the discharge tube 524 and the reaction tube 541. In one embodiment, the discharge tube 524 is positioned concentrically within the reaction tube 541.
The feedstock flow through the reaction tube 541 passes through the annulus 520. For example, the feedstock material (and/or a process gas from a feedstock 545 and/or a process gas source 546) may flow through the annulus 520 in the reaction tube 541 into the reaction Date Recue/Date Received 2021-10-01 zone 504. In such an embodiment, the plasma _conning material (from a plasma forming material source 530) is chosen to have a first dielectric strength that is less than a second dielectric strength of the feedstock material. The lower dielectric strength of the plasma forming material in comparison to the feedstock material facilitates non-thermal plasma 525 generation from the plasma forming material in the plasma forming zone 502 while the feedstock material passes into the reaction zone 504 and is subjected to the dense plasma head 525(a) of the non-thermal plasma in the reaction zone 504 in addition to the microwaves transmitted by the dense plasma heard 525(a). In an embodiment, the feedstock material may be partially ionized by the microwave radiation received from the radiation source 522 via the waveguide 523 in the plasma forming zone 502.
[0117] The reaction vessel 442 may also include a static and/or fluidized catalytic bed (not shown here), such as various metals, metal oxide salts or powders, carbon material, or other metallic materials or organometallic species which may enhance the reaction caused by dense plasma head 425(a) as described below. Examples of catalysts may include materials containing iron, nickel, cobalt, molybdenum, carbon, copper, silica, oxygen, zeolites or other materials or combinations of any of these materials. Alternatively, the feedstock material may be supplemented with any suitable catalyst or supplemental material.
Alternatively, no catalyst may be used. In an embodiment, as the distance between a catalyst bed (in the reaction vessel) and the interface element 410 is increased and/or the diameter of the inlet of the dense plasma head is reduced, the transmitted microwave power intensity reduces, leading to a decrease in the proportion of ionized and activated species, as well as the concentration of free electrons. Thus, through modification of the above distance, diameter of the dense plasma head and/or other parameters, it is possible to vary (or reduce to zero) the exposure of a catalyst bed contained within reaction vessel to microwave radiation, degree of gas ionization, ratio of radical species, and/or other parameters in order to optimize conversion rate, energy efficiency, catalyst durability, and/or other performance metrics of the reaction.
[0118] One or more flow distributors may be used to create the fluidized bed of feedstock material and/or catalytic material in the reaction vessel 442. It will be understood that while FIGS. 4 and 2 illustrate a down-flow mode for the feedstock material, up-flow or parallel flow modes are within the scope of this disclosure.
[0119] The feedstock and/or catalytic materials may be in powder form (such as coal particles), optionally entrained in a gas such as a process gas (e.g., a mixture of natural gas, hydrogen or argon). In an embodiment, the feedstock material may include hydrogen and/or carbon containing gases, liquids, and other materials such as, without limitation, aromatic alkylated aromatic, paraffinic, olefinic, cycloolefin, napthenic, alkane, alkene, Date Recue/Date Received 2021-10-01 alkyl cycloalkane, alkylated cycoalkane, alkyne, or heteroatom hydrocarbons;
methane, ethane, propane, butane, acetylene, syngas, natural gas, hexane, benzene, paraffins, naphthalene, polyaromatics other hydrocarbon gases, hydrogen, carbon monoxide, carbon dioxide, water vapor, hydrogen sulfide, hydrogen cyanide, alcohols (ethanol, methanol, propanol, and others), phenolic, paraffinic, naphthenic, aromatic compounds, and or combinations thereof. The gas flow rate of the feedstock material may be about 40 standard liters per minute (SLPM) to about 400 SLPM, about 20 SLPM to about 90 SLPM, about 30 SLPM to about 70 SLPM, or about 40 SLPM to about 60 SLPM, or about 400 SLPM to about 20,000 SLPM. In certain embodiments, the feedstock may be in vapor phase, when process gas temperature is higher than the boiling point of the feedstock or feedstock fractions and compounds. It may also be in liquid form as an atomized spray, droplets, emulsions, or aerosols entrained in a process gas.
[0120] The process gas may include, for example, hydrogen, nitrogen, methane or other compounds of hydrogen and carbon. Multiple process gas sources may be available so that a combination of process gases is directed into the reaction zone. An example process gas combination includes an inert gas such as argon, helium, krypton, neon or xenon. The process gas also may include carbon monoxide (CO), carbon dioxide (CO2), water vapor (H20), methane (CH4), hydrocarbon gases (GH2n+2, Caln, where n=2 through 6), nitrogen (N2) and hydrogen (H2) gases.
[0121] In one embodiment, the gas hourly space velocity GHSV is measured at standard temperature and pressure STP (e.g., 273.45 degrees Kelvin and 4 atmosphere of pressure) based on a volume of the reaction plasma region 425a and is generally about 4.58E+04 hr-4to about 4.58E+06 hr-4, but can be as low as about 4 hf4to about 400 hr-4, and about 400 hr"4 to about 4.58e+04 hr-4. More preferably, the GHSV is about 5.00E+04 lif4 to about 5.00E+05 hr-4, and most preferably the GI-ISV is about 7.75E+04 hi-4 to about 8.85E+05 hr4. Specifically, in an embodiment the GHSV is about 8.27E5 hr-4 within the reaction plasma region 425a.
[0122] In an embodiment, the non-thermal plasma received in the reaction zone 404 initiates selective conversion of the feedstock material to the product comprising graphitic materials. Products may also include hydrogen and/or chemicals such as ammonia. For example, the streamers or diffused the non-thermal plasma may act as an energy transfer catalyst activating the feedstock material and enabling acceptance of additional microwave energy into the feedstock material. The ions and electrons within the streamers or diffuse non-thermal plasma 425 collide with the feedstock material to selectively activate particular Date Recue/Date Received 2021-10-01 molecular modes resulting in an overall increase in energy efficiency compared with traditional thermodynamic or thermal-catalytic chemical dissociation. The collisions result in energy transfer sufficient to promote cleavage of a bond (e.g., hydrogen atom to a carbon atom bond) of the feedstock material. For example, if the feedstock material is methane, the I-13C-H bond is cleaved by electron collisions.
101231 The interaction of streamers or diffuse plasma with the feedstock material occurs at a convergence point 455 within the non-thetinal plasma in the reaction zone 404.
At the convergence point 455, the non-thermal plasma dynamically changes composition.
At the convergence point 455, the non-thermal plasma dynamically changes composition.
For example, the streamers converge, and in one embodiment, begin to extinguish (e.g., become less ionized). In one embodiment, the feedstock material receives a threshold amount of energy from the collision(s) with the ions and electrons within the non-theitiial plasma and/or receives a threshold amount of energy from the microwave radiation wherein the feedstock material is at least partially ionized (e.g., greater than 0 percent to 400 percent). After receiving the threshold amount of energy, the feedstock material is also ionized forming a non-thermal plasma within the convergence point 455. In one embodiment, the non-thermal plasma formed from the feedstock material has a C2 species temperature range of 4,500 to 5,500 degrees Kelvin, and in one embodiment, a C2 species temperature range of 2,000 to 3,500 degrees Kelvin, and in one embodiment, a C2 species temperature range of 500 to 4,500 degrees Kelvin. In one embodiment, the radiation intensity of the non-thermal plasma 425 is more uniform at the convergence point 455 than at the streamers. Accordingly, the non-thermal plasma 425 changes composition along a distance of the reaction zone 404.
101241 In one embodiment, the feedstock material receives energy from collision(s) with the ions and electrons within the non-thermal plasma comprised of plasma-forming material to selectively dissociate the feedstock material. In a region outside of the dense plasma head region within the reaction zone 404 dissociated species are quenched and preferentially rejoin to form products. In one embodiment, the product comprises a carbon-enriched material and a hydrogen-enriched material. The carbon-enriched material has a hydrogen atom to carbon atom ratio of less than or equal to one. For example, the carbon-enriched material may include, but is not limited to, a graphitic material, amorphous carbon, structured carbon, and ordered carbon. The carbon-enriched material may include graphene of varying lateral dimension and atomic layers, amorphous and carbon blacks, and/or graphite. Carbon-enriched materials may include acetylene, benzene, and polyaromatic Date Recue/Date Received 2021-10-01 materials such as naphthalene, anthracene, phenanthrene, and others. The hydrogen enriched material may include, but is not limited to, hydrogen, ethylene, acetylene, butadiene, butane, and combinations thereof. In one embodiment, the conversion percentage of the feedstock material to the product on a molar basis may be, but is not limited to, at least 5 percent, at least 30 percent, at least 70 percent, at least 90 percent, and at least 99 percent. For example, in one embodiment, the conversion percentage of the feedstock material to the product on a molar basis of may be between 30 and 70 percent.
Accordingly, the feedstock material is selectively converted to the product within reaction zone 404.
[0125] In one embodiment, the dense plasma head 425(a) of the non-thermal plasma 425 within the reaction zone 404 lowers the effective activation energy required for a chemical reaction, such as the selective conversion of the feedstock material to the product.
[0126] In one embodiment, feedstock material is methane. The methane is selectively converted into a carbon enriched material utilizing the system of according to, but not limited to, the following reactions:
4 CH,, ¨> CH3 + H
(2) CH4 + H CH3 + H2 (3) CH3 + CH3 ¨> C2 H6 4 C2H6 ¨> C2H4 + H2 (5) C2H4 C2H2 + H2 (6) C2H2 ¨> carbon based material + H2 7 CO2 + H2 C (S) + H20 101271 In one embodiment, reactions 4-7 occur in the reaction zone 404 and at least one of the reactions 4-7 is facilitated by the dense plasma head 425(a) of the non-thermal plasma 425. The carbon enriched material produced from methane has a hydrogen atom to carbon atom ratio of less than or equal to one. For example, the carbon enriched material and/or solid carbon may include, but is not limited to, a graphitic material, amorphous carbon, structured carbon, and ordered carbon. The carbon enriched material may include graphene and/or graphite. Accordingly, methane may be selectively converted into graphene and/or graphite utilizing the non-thermal plasma 425.
[0128] With respect to reaction 7, in conventional chemistry, conversion of carbon dioxide and hydrogen into water and solid carbon is known as the Bosch reaction and proceeds according to the following reaction. CO2 + H2 -> C(s) + H20. This reaction may be carried out using the systems and methods disclosed in this disclosure for the production Date Recue/Date Received 2021-10-01 of solid carbon. In one embodiment, a feedstock gas comprising carbon-containing gas such as carbon dioxide or carbon monoxide, and a hydrogen-containing gas such as hydrogen, methane, ethane, acetylene, or mixture thereof is dissociated using the dense plasma head.
The radicals formed are then recombined within the reaction zone to form water vapor solid carbon. The feedstock gas may also include, without limitation, syngas, shale gas, or biogas.
In one embodiment, the reaction may be catalyzed using, for example, cobalt, nickel, or other transition metal on a support material to facilitate the reaction.
Alternatively, no catalyst is added.
[0129] In an embodiment, the graphitic materials include graphene sheets that have a size with an X-Y dimension of about 50-400 nm, about 50-500 nm, about 400-400 nm, about 450-350 nm, or about 200-300 nm (i.e., the graphene sheets are nano-graphene sheets). The nano-graphene sheets are formed as a stack of about 2 sheets to about 8 sheets, about 3 sheets to about 7 sheets, about 4 sheets to about 6 sheets, and/or a single sheet. The unique size and morphology of such nano-graphene sheets leads to improvement in barrier properties of the graphene sheets. Furthermore, the pure graphitic composition of the product leads to excellent electrical and thermal conductivity. Additionally and/or alternatively, the graphitic materials produced may also include amorphous and semi-graphitic carbon particles. The differentiation is based on relative oxidation rates, lamellae size and degree of order. In an embodiment, the relative yield of these three carbon "phases"
¨ nano-graphene, amorphous and semi graphitic particles may be controlled by controlling the reaction conditions. In an embodiment, specific graphitic material products are single or few-layer graphene platelets of a lateral dimension 400-200 nm. Graphene platelets may have flat edges. Graphene platelets may be 4-40 layers, more preferably 4-3 layers, or most preferably, single layer. Graphene platelets may be folded, scrolled, curved, flat, or etched.
Graphene platelets may be functionalized, chemically pure, or pristine. In another embodiment, graphene platelets are functionalized to include nitrogen, boron, oxygen, or other functional group to enhance dispersability within a media, conductivity, selective adsorbance, or other properties. Specifically, the reaction conditions may be varied to produce graphitic materials that primarily include single layer nano-graphene sheets having lateral have a size with an X-Y dimension of at least 400 nm, and that have flat edges (rather than scrolled and/or etched edges).
[0130] For example, the molar ratio of a Cf14:H2 in a feedstock material may be varied to vary the production yields of different graphitic materials (while the flow rate is maintained constant using, for example, argon as a process gas and varying the argon Date Recue/Date Received 2021-10-01 concentration). Increasing the ratio of added H2 in the feedstock material increases the graphitic nature of the products with pristine few-layer graphene sheets and graphitic particles seen at the highest feed Hz content and reduction in the amount of amorphous carbon particles. When increasing the Hz: CH4 ratio, carbon product distribution is observed to shift from more amorphous and/or generic carbon types toward more graphitic/graphenic carbon types. Specifically, selectivity of graphene nanoplatelets increases with increasing Hz: CH4 ratio. The molar ratio of CH4:H2 in a feedstock material may be between about 5:0 to about 4:4, about 4:4 to about 2:4, about 3:4 to about 2.5:4, or the like.
101311 In an example embodiment, in the absence of H2, the graphitic materials include amorphous spheres, semi-graphitic polyhedral particles, and nano-graphene sheets, observed in stacks of 6-40 layers. The amorphous particles appear together, partially fused or merged indicative of their continued growth past coalescence. The semi-graphitic particles have recognizable nanostructure ¨ defined lamellae of extended length and order, characteristic of graphitized forms of carbon blacks. The graphene sheet stacks define the particle boundary, leading to a polyhedral morphology and shell-like appearance. The nano-graphene stacks appear curled and/or co-mingled with these other forms. FIG. 6 illustrates the transmission electron microscopy (TEM) images of the graphitic materials obtained in the absence of H2. In an embodiment, the relative weight percentages of amorphous particles, semi-graphitic particles, and nano-graphene sheets in the absence of H2 was found to be about 30%, about 40%, and about 30%, respectively.
101321 In another example, a molar ratio of 2.5:4 for CH4:H2 in a feedstock material lead to an increase in the formation of semi-graphitic particles particularly fused to the edges of the nano-graphene sheets. Furthermore, the amorphous spheres were found to have increased level of internal structure (recognizable short lamellae), the semi-graphitic particles were found to have better lamellae definition, and the nano-graphene sheets were folded. FIG. 7 illustrates the TEM images of the graphitic materials obtained at the molar ratio of 2.5:4 for CH4:H2. In an embodiment, the relative weight percentages of amorphous particles, semi-graphitic particles, and nano-graphene sheets at this molar ratio was found to be about 20%, about 40%, and about 40%, respectively.
101331 In yet another example, at a molar ratio of 4:4 for CH4:H2 in a feedstock material lead to the disappearance of amorphous spheres and an overall increase in the graphitic content of the product. Furthermore, the number of nano-graphene layers in the stacks was found to be lesser (e.g., 2-6 layers). FIG. 8 illustrates the TEM
images of the graphitic materials obtained at the molar ratio of 4:4 for CH4:H2. In an embodiment, the Date Recue/Date Received 2021-10-01 relative weight percentages of amorphous particles, semi-graphitic particles, and nano-graphene sheets at this molar ratio was found to be about 0%, about 50%, and about 50%, respectively.
101341 As such, increasing the H2 ratio in the feedstock material lead to an increase in the graphitic content of the product as is evident from the high fraction of graphitic particles and absence of amorphous particles in the above example embodiments.

Furthermore, increasing the concentration of H2 in the feed stream increases both the phase purity and phase quality of graphene and graphitic particles in the product.
For example, as the hydrogen content in the feedstock material is increased, the nano-graphene sheets become relatively flatter with improved edge definition and stacking uniformity.
Furthermore, the number of layers in the stacks reduces leading of high crystallinity of the nano-graphene sheets. The sp2 character also increases with increasing IT2 in the feed stream which is an indication of improvement in the quality of nano-graphene formed.
Similarly, the internal structure (e.g., lamellae length) increases for the graphitic particles.
101351 Referring back to FIG. 4, a conduit 444 may be provided in communication with a side of the reaction vessel 442 that does not include the interface element 410. The conduit 444 may control and/or facilitate egress of material(s) from the reaction vessel 442, including egress of material(s) from the reaction zone 404. Namely, the conduit 444 controls egress of a stream 434 from the reaction zone 404. The stream 434 may include, but is not limited to, the product including graphitic materials, the plasma forming material (e.g., unconverted, extinguished non-thermal plasma, etc.), the feedstock material (e.g., unconverted, partially converted, etc.), and combinations thereof. In one embodiment, the conduit 424 may be, but is not limited to, a pipe, a tube, an orifice, a channel, a nozzle, an outlet, and combinations thereof. The positioning of the conduit 444 is for illustration purposes and should not be considered limiting. Accordingly, the conduit 444 controls egress of materials from the reaction zone 404.
101361 In one embodiment, the bulk temperature of the stream 434 may be about 75 to about 2800 C, about 200 to about 4300 C, about 300 to about 4000 C, or about 400 to about 700 C. In one embodiment, the bulk temperature of the stream 434 is obtained prior to cooling of the stream 434 and measured to be between 300 and 500 C. In one embodiment, a residence time of the reactants (i.e., the feedstock material and/or the process gas) within the reaction zone 404 is between 45 milliseconds and 30 seconds.
Date Recue/Date Received 2021-10-01 [0137] In one embodiment, at least a portion and/or a component of the stream 434 may be returned to the reaction zone 404 through a conduit (not shown) for recycling.
Accordingly, the stream 434 may include effluent egressing from the reaction zone 404.
[0138] The conduit 444 may be operatively coupled to a container 451 to collect the product. The container 451 may be any known or conceivable material capable of withstanding heat, pressure(s), and the chemical environment(s) associated with the product.
For example, the container 451 may be constructed of, but is not limited to ceramics, and metals or metal alloys, such as brass, copper, steel, nickel, stainless steel, titanium, and aluminum. In one embodiment, the vessel 442 is oriented such that particles (e.g., solids, liquids of product, etc.) free-fall through the conduit 444 (e.g., down-flow).
In one embodiment, the vessel 442 is oriented such that particles (e.g., solids, liquids of products, etc.) require an applied force to exit in stream 434 in the conduit 444 (e.g., up-flow). In one embodiment, the vessel 442 is oriented for a horizontal flow. Accordingly, the container 451 is configured to receive the product from the conduit 444.
[0139] Optionally, one or more conditioning devices, such as filters, membranes, settlers, centrifugal separators, distillation devices, or other processing devices may be provided between the vessel 442 and the contained 444 and/or after the container 444, described above. For example, a separator (e.g., a cyclone separator) and/or a filtration system may be used to collect entrained graphitic material particles before exhausting the remaining stream 434.
[0140] In one embodiment, the plasma forming material and/or feedstock material may include an additive such as, but are not limited to, carbon black, coal, biochar, biomass, graphite, coke, structured carbon, carbon dioxide, carbon monoxide, and hydrogen, nitrogen, lithium, and/or boron. The additive may accelerate the conversion of the feedstock material to the product, facilitate selectivity of a specific product, or facilitate improvement of the product by chemical, structural or other means. In one embodiment, the additive is exposed to the microwave radiation, the non-thermal plasma 125, and/or the dense plasma head 125(a). In one embodiment, the additive is upgraded to a third material responsive to the exposure. In one embodiment, the upgrading may change the chemical, physical, and/or structural properties of the additive. For example, conductivity of the additive can be increased through re-ordering and/or functionalization of the additive's surface or bulk structure (e.g., carbon black may be upgraded to conductive carbon black). In one embodiment, the additive's surface area and/or porosity may be altered (carbon to activated carbon). In one embodiment, graphite may be upgraded to, but not limited to, a graphene Date Recue/Date Received 2021-10-01 sheet. In one embodiment, the additive increases conversion of the feedstock material to product. Accordingly, an additive may be added to the system for accelerated and/or increased conversion of the feedstock material and/or generation of a third material. In one embodiment, the additive may prevent formation of particular structures (e.g.
amorphous carbon) facilitating an increase in production of more desirable structures (e.g. graphene platelets).
101411 Referring to FIG. 9, a flow chart (900) is provided illustrating a method for processing the precursor material into the product utilizing the non-thermal plasma. As shown, a plasma forming material is delivered (e.g., provided) to a reaction zone 902 and a precursor material is delivered (e.g., provided) to the reaction zone 904. The method may also include delivering a plasma promoter material to the reaction zone in 904. In one embodiment, at least one of the plasma foi ming material and the precursor material includes an additive such as, but not limited to, carbon black, coal, biochar, biomass, graphite, structured carbon, carbon dioxide, carbon monoxide, and hydrogen. The reaction zone is exposed to microwave radiation 906, including exposing the plasma forming material and the precursor material to the microwave radiation. The exposure of the plasma forming material to the microwave radiation selectively converts the plasma forming material to a non-thermal plasma including formation of one or more streamers 908. In one embodiment, the conversion of the plasma forming material to the non-thermal plasma is initiated prior to mixing the plasma forming material with the precursor material. In one embodiment, the plasma forming material is maintained separate from the plasma foiming material during initiation of exposure of the plasma forming material to the microwave radiation.
Accordingly, the non-thermal plasma, including the one or more streamers, is generated within the reaction zone from the plasma forming material.
101421 The precursor material interacts with the plasma forming material 910.
During the interaction the precursor material is exposed to the non-thermal plasma including exposure to the one or more streamers In one embodiment, the exposure of the precursor material to the microwave radiation is initiated prior to exposure of the precursor material to the non-thermal plasma. In one embodiment, the precursor material is maintained separate from the plasma forming material during initiation of the exposure of the precursor material to the microwave radiation. The exposure of the precursor material to the non-thermal plasma and the microwave radiation selectively converts the precursor material to a product 912. In one embodiment, the product comprises a carbon enriched material and a hydrogen enriched material. In one embodiment the conversion of the Date Recue/Date Received 2021-10-01 precursor material to the product is enhanced (e.g., activation energy is lowered and/or conversion yield increased) by the additive. In one embodiment, the additive is selectively converted to a third material from exposure of the additive to the microwave radiation and/or non-thermal plasma 914. Accordingly, the precursor material is selectively converted into the product by the non-thermal plasma.
[0143] Referring to FIG. 10, a flow chart 1000 is provided illustrating a method for processing the feedstock material into the product comprising graphitic materials utilizing the non-thermal plasma. While the processing method 1000 is described for the sake of convenience and not with an intent of limiting the disclosure as comprising a series and/or a number of steps, it is to be understood that the process does not need to be performed as a series of steps and/or the steps do not need to be performed in the order shown and described with respect to FIG. 10, but the process may be integrated and/or one or more steps may be performed together, or the steps may be performed in the order disclosed or in an alternate order.
[0144] At 1002, a plasma forming material may be delivered (e.g., provided) to a plasma forming zone and exposed to microwave radiation. The exposure of the plasma foiming material to the microwave radiation may selectively convert the plasma forming material to a non-thermal plasma including formation of one or more streamers and/or diffused plasma at 1004. Accordingly, the non-thermal plasma, including the one or more streamers, is generated within the reaction zone from the plasma forming material.
[0145] At 1006, the non-theimal plasma may be delivered to a reaction zone in the form of the dense plasma head via an interface element. At 1008, a feedstock material may be delivered (e.g., provided) to the reaction zone. In one embodiment, at least one of the plasma forming material and the precursor material includes an additive such as, but not limited to, carbon black, coal, biochar, biomass, graphite, structured carbon, carbon dioxide, carbon monoxide, and hydrogen.
[0146] The feedstock material may interact with the non-thermal plasma (1010).
During the interaction the feedstock material is exposed to the non-thermal plasma including exposure to the one or more streamers. In one embodiment, the exposure of the feedstock material to the microwave radiation is initiated prior to exposure of the feedstock material to the non-thermal plasma. The exposure of the feedstock material to the non-thermal plasma (and optionally the microwave radiation) selectively converts the feedstock material to a product comprising graphitic materials (1012). Accordingly, the feedstock material is selectively converted into the product by the non-thermal plasma.

Date Recue/Date Received 2021-10-01 [0147] It should be noted that while the above disclosure describes the conversion of feedstock material to products comprising graphitic materials, the systems and methods of the current disclosure may also be used for the production of other products such as, without limitation, products of acetylene hydrogenation, ammonia, or other types of chemicals.
[0148] Acetylene hydrogenation:
[0149] The systems and methods described above may be used for hydrogenation of acetylene to ethylene and other hydrogen-enriched carbon-based compounds. The reaction may be carried out in the presence or absence of a catalyst bed. In an embodiment, a catalyst bed may be added to the reaction vessel to promote or facilitate hydrogenation of a feedstock gas stream. The bed of catalyst material may include a transition metal, such as, without limitation, titanium, nickel, copper, zinc, gold, silver, platinum, palladium, or iron, on a support material. Examples of support material may include, without limitation, activated carbon, glass beads, alumina, and/or silicon dioxide pellets In an example embodiment, when a feedstock gas stream containing acetylene and hydrogen is passed into the reaction vessel containing a fluidized bed of catalyst (e.g., nickel supported by activated carbon), the acetylene may be hydrogenated in the presence of the dense plasma head into ethylene and other hydrogen-enriched carbon-based compounds. The ratio of the mass of transition metal to catalyst support material may be about 1% to about 100%, more preferably about 5% to about 50%, and most preferably about 10% to about 25%.
[0150] In one embodiment, the GHSV, for the hydrogenation reaction, calculated based on the volumetric flow rate divided by the un-packed volume of catalyst bed is about 100 hr-1 to about 1,000 hr-1, but more preferably about 1,000 hr-1 to about

10,000 hr'. In an embodiment, the bed of catalyst material may be heated by direct contact between the non-thermal plasma or by other means to a temperature about 500 Kelvin to about 10,000 Kelvin, more preferably about 500 Kelvin to about 1000 Kelvin.
101511 Ammonia Production:
[0152] In conventional chemistry, synthesis of ammonia is performed via the Haber-Bosch process and proceeds at relatively high pressures of 60-180 bar and relatively high temperatures of 673-773 Kelvin over a bed of metal catalyst material. The fundamental reaction can be described as: N2 + 3H2 -> 2NH3. It is well known that diatomic nitrogen (N2) is very unreactive due to the strength of its triple bond. As such, there is a need for systems and methods that can provide energies high enough for the disassociation of the triple bond. Non-thermal plasmas generated in the systems and methods of the current disclosure can be used for production of ammonia because non-thermal or non-equilibrium Date Recue/Date Received 2021-10-01 plasmas can readily achieve electron energies high enough to dissociate diatomic nitrogen (9.79 eV/bond at 298 Kelvin).
101531 In one embodiment, a nitrogen containing feedstock is used in conjunction with a hydrogen-containing feedstock for the synthesis of ammonia using non-thermal plasma. The molar ratio of nitrogen to hydrogen of may be about 1:1 to about 1:5, and preferably about 1:3. In one embodiment, for production of ammonia, nitrogen and/or hydrogen containing feedstock is dissociated via direct contact with the dense plasma head within the reaction zone, which are then recombined to form ammonia vapor. In one embodiment, the reaction vessel may include a catalyst capable of facilitating the recombination of ammonia from nitrogen and/or hydrogen-containing radicals. An example catalyst may include an iron-containing compound in addition to a promotor material such as, without limitation, potassium oxide, calcium oxide, silicon dioxide, aluminum oxide, and/or other oxides. In one embodiment, for the production of ammonia, the pressure in the reaction vessel is about 0.5 bar to about 1.5 bar. In another embodiment, the reaction vessel may be about 10 bar to about 100 bar, more preferably, about 1.5 bar to about 10 bar. In one embodiment, the temperature of reaction vessel is maintained between 500 Kelvin and 1000 Kelvin to facilitate ammonia recombination.
101541 Example 1 101551 In one example, a precursor processing system was configured similar to the configuration of the system in FIG. 2A to process methane into graphitic materials, such as graphene, utilizing non-thermal plasma. The system was in flow configurationA.
Namely, methane is the precursor material 232a and the second conduit 222 is configured to flow the methane through the annulus 222c between the second surface 222b of the second conduit 222 and the first surface 220b of the first conduit 220 into the reaction zone 204. The methane was 23% methane and 77% argon by volume. The methane was flowing through the reaction zone at a GHSV of 12,000 per hour. The plasma forming gas was argon and the first conduit 220 was configured to flow the argon into the reaction zone 204.
The argon was 99.9% argon by weight. The argon was flowing through the reaction zone at a GHSV
of 2,600 per hour. The argon and methane were introduced to the reaction zone 204 at a temperature between 280 degrees Kelvin and 310 degrees Kelvin and 1 atmosphere of pressure. Accordingly, the system was configured in flow configurationA with the methane encompassing the argon through at least a portion of the reaction zone.
101561 The vessel 204 was configured to generate streamers. Namely, the first, second, and third conduits, 220, 222, and 224 were comprised of quartz. The second conduit Date Recue/Date Received 2021-10-01 222 was an extension of the fifth conduit 228. The second conduit 222 was used within the cavity of the vessel to control and facilitate the traversal of the reactants and product(s) (e.g., graphene) through the reaction zone 204 into the third conduit 224. The reaction zone 204 was 2.2 centimeters in diameter by 15 centimeters in length. The vessel 202 was comprised of aluminum and the vessel 202 had a 9 centimeter internal diameter.
The radiation source 240 was a magnetron connected to the chamber 202 by a waveguide 242 comprised of aluminum. The microwave radiation 240a was at a frequency of 2.45 GHz at a concentration within the reaction zone of 9 kW per liter. Upon exposure of the reactants to the microwave radiation 240a, a non-thermal plasma 250 was generated within the reaction zone 204, including the generation of streamers 250a. The non-thermal plasma interacted with the reactants to form graphitic materials 234a, such as graphene. The conversion rate of methane to product(s) was measured to be 36% on a molar basis.
Accordingly, methane was processed into products including at least a portion of the product being graphene utilizing non-thermal plasma.
[0157] An Ocean Optics HR2000+ES ¨ Emission Spectrometer, hereinafter Spectrometer, was used to measure the emission spectra of the non-thermal plasma within the reaction zone. The Spectrometer has detectable range of 190-1100 nanometers and a 0.9 full width half maximum resolution. The emissions detected by the Spectrometer are excited and/or ionized species within the reaction zone. For example, ionized argon emissions appear between 650 and 900 nanometers (e.g., argon lines at 696 and 751 nanometers) while C2 emission bands are present between 400 and 600 nanometers. The C2 emission bands are indicative of graphitic compound formation such as graphene. Non-excited and non-ionized species may not be detected by the Spectrometer. The emission spectra of the non-thermal plasma were captured at varying distances along a length of the reaction zone.
Accordingly, the Spectrometer monitors the characteristics of the non-thermal plasma.
[0158] Referring to FIG. 11, a graph 1100 is provided illustrating an emission spectra of the non-thermal plasma with respect to a distance traversed through the reaction zone. The first emission spectrum 1102 was taken at a positioned closest to the inlet of the reaction zone 205. Each successive emission spectrum, 1106-1116, is positioned further from the inlet with the eighth emission spectrum 1116 being closest to an outlet of the reaction zone 204. As shown, at 0.95 to 3.0 centimeters from the inlet, primarily streamers 250a were visibly present. The first emission spectrum 1102, captured at 0.95 centimeters from the inlet, shows primarily ionized argon species emissions and minimal C2 emissions.
At 3 centimeters from the inlet, the convergence point 250b of non-thermal plasma 250 was Date Recue/Date Received 2021-10-01 visibly present. The second emission spectrum 1104, captured at 3 centimeters from the inlet, shows an increase in C2 emissions and a decrease in ionized argon species emissions compared to the first emission spectrum 1102. The changes in emissions indicate the streamers 250a are beginning to extinguish. At 4.8 centimeters from the inlet, the convergence point 250b of the non-thermal plasma 250 is visibly present. The third emission spectrum 1106, captured at 4.8 centimeters from the inlet, shows the C2 emissions continue to increase and the ionized argon species emissions are minimal.
Accordingly, as shown, the non-theimal plasma is dynamically changing within the reaction zone.
[0159] Additional emission spectra were captured throughout the length of the reaction zone 204. For example, a fourth emission spectrum 508 was captured at 6.7 centimeters from the inlet; a fifth emission spectrum 1110 was captured at 8.6 centimeters from the inlet; a sixth emission spectrum 1112 was captured at 10.5 centimeters from the inlet; a seventh emission spectrum 1114 was captured at 12.4 centimeters from the inlet; and the eighth emission spectrum 1116 was captured at 14.3 centimeters from the inlet. At distances, 6.7, 8.6, 10.5, 12.4, and 14.3 centimeters, the C2 emissions bands continue to remain present within the respective emission spectrum, 1108, 1110, 1112, 1114, and 1116 while the ionized argon species emission is minimal. Accordingly, the emission spectra of C2 band region of the reaction zone 204 are relatively unchanged after 6.7 centimeters from the inlet of the reaction zone 204 to the outlet of the reaction zone 204.
[0160] Example 2 [0161] In one example, a precursor processing system was configured similar to the configuration of the system in FIG. 3 to process methane into graphitic materials, such as graphene, utilizing non-thermal plasma. The system was in flow configurationA.
Namely, methane is the precursor material 332a and the second conduit 322 is configured to flow the methane through the annulus 322c between the second surface 322b of the second conduit 322 and the first surface 320b of the first conduit 320 into the reaction zone 304. The methane was 23% methane and 77% argon by volume. The methane was flowing through the reaction zone at a GHSV of 12,000 per hour.
[0162] The plasma forming gas was argon and the first conduit 320 was configured to flow the argon into the reaction zone 304. The argon was 99.9% argon by weight. The argon was flowing through the reaction zone at a GHSV of 2,600 per hour.
Carbon black is the plasma promoter material 336a and is entrained within the flow of argon through the first conduit 320. The carbon black was introduced to the reaction zone at 0.06 grams per liter of gas reactant flow (e.g., grams of carbon black per liter of gas flow (e.g., argon)).The Date Recue/Date Received 2021-10-01 argon, methane, and carbon black were introduced to the reaction zone 304 at a temperature between 280 degrees Kelvin and 310 degrees Kelvin and 1 atmosphere of pressure.
Accordingly, the system was configured in flow configurationA with the methane and carbon black encompassing the argon through at least a portion of the reaction zone.
101631 The vessel 304 was configured to generate micro-plasma and streamers.
Namely, the first, second, and third conduits, 320, 322, and 324 were comprised of quartz.
The second conduit 322 was an extension of the fifth conduit 328. The second conduit 322 was used within the cavity of the vessel to control and facilitate the traversal of the reactants and product(s) (e.g., graphene) through the reaction zone 304 into the third conduit 324. The reaction zone 304 was 2.2 centimeters in diameter by 15 centimeters in length.
The vessel 302 was comprised of aluminum and the vessel 302 had a 9 centimeter internal diameter.
The radiation source 340 was a magnetron connected to the chamber 302 by a waveguide 342 comprised of aluminum. The microwave radiation 340a was at a frequency of GHz at a concentration within the reaction zone of 9 kW per liter. Upon exposure of the reactants to the microwave radiation 340a, a non-thermal plasma 250 was generated within the reaction zone 304, including the generation of micro-plasma 250a and streamers 250c.
The non-thermal plasma 250 interacted with the reactants to form graphitic materials 334a, such as graphene. The conversion rate of methane to product(s) was measured to be 36% on a molar basis. Accordingly, methane was processed into products including at least a portion of the product being graphene utilizing non-theimal micro-plasma.
101641 An Ocean Optics HR2000+ES ¨ Emission Spectrometer, hereinafter Spectrometer, was used to measure the emission spectra of the non-thermal plasma within the reaction zone. The Spectrometer has detectable range of 190-1100 nanometers and a 0.9 full width half maximum resolution. The emissions detected by the Spectrometer are excited and/or ionized species within the reaction zone. For example, ionized argon emissions appear between 650 and 900 nanometers (e.g., argon lines at 696 and 751 nanometers) while C2 emission bands are present between 400 and 600 nanometers. The C2 emission bands are indicative of graphitic compound formation such as graphene and/or excitation of a plasma promoter material such as, but not limited to, carbon black. Non-excited and non-ionized species may not be detected by the Spectrometer. The emission spectra of the non-thermal plasma were captured at varying distances along a length of the reaction zone.
Accordingly, the Spectrometer monitors the characteristics of the non-thermal plasma.
101651 Referring to FIG. 12, a graph 1200 is provided illustrating an emission spectra of the non-thermal plasma with respect to a distance traversed through the reaction Date Recue/Date Received 2021-10-01 zone. The first emission spectrum 1202 was taken at a position closest to the inlet of the reaction zone 1204. Each successive emission spectrum, 1204-1216, is positioned further from the inlet with the eighth emission spectrum 1216 being closest to an outlet of the reaction zone 1204. As shown, the first emission spectrum 1202, captured at 0.912 centimeters from the inlet and the second emission spectrum 1204, captured at 3.0 centimeters from the inlet, show minimal excited species are present and blackbody radiation is present (e.g., increase in intensity of the spectra at greater than 550 nm) due to formation of micro-plasma 250a. At 3 centimeters from the inlet, the convergence point 250d of the micro-plasma 250a and the streamers 250c were visibly present and the reactants have begun to mix. The second emission spectrum 1204, captured at 3 centimeters from the inlet, shows an increase in C2 emissions compared to the first emission spectrum 1202. The change in emissions indicates the micro-plasma 250a is more intensive in the second emission spectrum 1204 as compared to the first emission spectrum 1202 and the conversion of the methane into products has been initialized. The micro-plasma 250a in the second emission spectrum 1204 is primarily composed of carbon species such as, but not limited to, C2. At 4.8 centimeters from the inlet, the convergence point 250d is visibly present. The third emission spectrum 1206, captured at 4.8 centimeters from the inlet, shows the C2 emissions increase to a maximum point and blackbody emissions are lower as compared to the first and second emission spectra, 1202 and 1204, respectively, indicating energy transfer from the micro-plasma 250a to the methane. Accordingly, as shown, the non-thermal plasma is dynamically changing within the reaction zone.
101661 Additional emission spectra were captured throughout the length of the reaction zone 304. For example, a fourth emission spectrum 1208 was captured at 6.7 centimeters from the inlet; a fifth emission spectrum 1210 was captured at 8.6 centimeters from the inlet; a sixth emission spectrum 1212 was captured at 10.6 centimeters from the inlet; a seventh emission spectrum 1214 was captured at 12.4 centimeters from the inlet; and the eighth emission spectrum 1216 was captured at 14.3 centimeters from the inlet At distances, 6.7, 8.6, 10.6, 12.4, and 14.3 centimeters, the C2 emissions bands continue to remain present within the respective emission spectrum, 1208, 1210, 1212, 1214, and 1216 while the ionized argon species emission is minimal. Accordingly, the emission spectra of C2 band region of the reaction zone 304 are relatively unchanged after 6.7 centimeters from the inlet of the reaction zone 304 to the outlet of the reaction zone 304.
101671 The flow charts and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer Date Recue/Date Received 2021-10-01 program products according to various embodiments. In this regard, each block in the flow charts or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flow chart illustration(s), and combinations of blocks in the block diagrams and/or flow chart illustration(s), can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
[0168] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises"
and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
[0169] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided, such as examples of agents, to provide a thorough understanding of the disclosed embodiments. One skilled in the relevant art will recognize, however, that the embodiments can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the embodiments [0170] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present embodiments has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the embodiments in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the Date Recue/Date Received 2021-10-01 embodiments. The embodiment was chosen and described in order to best explain the principles of the embodiments and the practical application, and to enable others of ordinary skill in the art to understand the embodiments for various embodiments with various modifications as are suited to the particular use contemplated. Microwave radiation is utilized to generate a non-thermal plasma including streamers to facilitate the conversion of the precursor material(s) to the product(s) while minimizing carbon build up and/or energy consumption. In one embodiment, the streamers enable the same (or higher) conversion rates and/or product selectivity than prior processes (e.g., thermal plasma) with a lower microwave radiation density within the reaction zone than the prior processes.
101711 It will be appreciated that, although specific embodiments have been described herein for purposes of illustration, various modifications may be made without departing from the spirit and scope of the embodiments. In particular, the vessel may be configured in a variety of flow configurations and orientations. For example, the first conduit may be in communication with a proximal side of the vessel that is oppositely positioned to a distal side of the vessel that the second conduit is in communication with.
Accordingly, the scope of protection of these embodiments is limited only by the following claims and their equivalents.

Date Recue/Date Received 2021-10-01

Claims

What is claimed is:

1. A method comprising: providing a plasma foiming material to a reaction zone; exposing the plasma forming material to microwave radiation, the exposure selectively converting the plasma forming material to a non-thermal plasma, the non-thermal plasma comprising one or more streamers; upon foimation of the non-thermal plasma, providing a hydrocarbon precursor material to the reaction zone; and exposing the hydrocarbon precursor material to the one or more streamers and the microwave radiation to form a convergence point within the non-thermal plasma where the hydrocarbon precursor material is at least partially ionized, such ionization selectively converting the hydrocarbon precursor material to a product including one or more carbon enriched materials and one or more hydrogen enriched materials, wherein the carbon enriched materials include one or more first materials selected from the group consisting of:
amorphous carbon, and structured carbon.

2. The method of claim 1, wherein the structured carbon is selected from the group consisting of graphene, graphite, and graphitic material.

3. The method of claim 1, wherein the hydrocarbon precursor material includes materials selected from the group consisting of: aromatic, alkylated aromatic, cycloolefin, napthenic, alkane, alkene, alkylated cycloalkane, alkyne, alcohol, and heteroatom.

4. The method of claim 1, further comprising providing an additive material for accelerating the conversion of the hydrocarbon precursor material to the product.

5. The method of claim 1, wherein the hydrocarbon precursor material includes materials selected from the group consisting of: methane, ethane, propane, butane, syngas, natural gas, methanol, ethanol, propanol, butanol, hexane, benzene, paraffin, and naphthalene.

6. The method of claim 1, wherein the plasma forming material includes materials selected from the group consisting of: argon, hydrogen, helium, neon, krypton, xenon, carbon dioxide, nitrogen, and water.

7. The method of claim 1, wherein at least one of the hydrocarbon precursor material and plasma forming material includes materials selected from the group consisting of:
carbon black, coal, coke, biochar, structured carbon, amorphous carbon, carbon dioxide, carbon monoxide, and hydrogen.

8. The method of claim 1, wherein the carbon enriched materials have a hydrogen atom to carbon atom ratio of less than or equal to 1.

9. The method of claim 1, wherein the hydrogen enriched materials have a hydrogen atom to carbon atom ratio of greater than 1.

10. The method of claim 1, wherein the hydrogen enriched materials include materials selected from the group consisting of: hydrogen, ethylene, acetylene, butadiene, and butane.

11. The method of claim 1, further comprising recycling an output of the reaction zone, including selectively returning at least one of an unconverted hydrocarbon precursor material and the plasma forming material to the reaction zone.

12. The method of claim 1, further comprising: positioning a first conduit and a second conduit proximal to the reaction zone, wherein the first conduit channels the plasma forming material;
and positioning the first conduit within the second conduit, the positioning including forming an annulus between a first surface of the first conduit and a second surface of the second conduit, wherein the annulus channels the hydrocarbon precursor material.

13. The method of claim 1, further comprising: orienting the reaction zone with respect to an outlet, wherein one or more solid particles free-fall through the outlet.

14. The method of claim 1, wherein the concentration of the microwave radiation is about 30 kilowatts per liter or less than 30 kilowatts per liter within the reaction zone.

15. The method of claim 1, wherein the temperature of the non-thermal plasma is less than 5,500 degrees Kelvin.

16. The method of claim 1, further comprising: initiating exposure of the hydrocarbon precursor material to the microwave radiation prior to exposing the hydrocarbon precursor material to the non-thermal plasma; and maintaining the hydrocarbon precursor material separate from the plasma forming material during the initiation of the exposure.

17. The method of claim 16, further comprising initiating exposure of the plasma forming material to the microwave radiation during the maintenance of the separation.

18. The method of claim 1, wherein the frequency of the microwave radiation is between 36 megahertz and 300 gigahertz.