Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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-theanal 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 anclior molecules (e.g., ions). Plasma may be, but not limited to, a
thennal 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.).
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Date regue/Date received 2023-02-24
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
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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.
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[0011] 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
foiming material
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Date regue/Date received 2023-02-24
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).
100171 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 founing
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. IA 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
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Date regue/Date received 2023-02-24
[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 (TEM
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 regue/Date received 2023-02-24
DETAILED DESCRIPTION
100341 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
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Date regue/Date received 2023-02-24
contains certain errors necessarily resulting from the standard variation
found in their
respective testing measurements.
100391 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-thermal
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
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Date regue/Date received 2023-02-24
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 Ito 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%.
100441 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 nanostructures 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.
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Date regue/Date received 2023-02-24
[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-thermal 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
forming 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
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Date regue/Date received 2023-02-24
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.
100491 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.
100501 Referring to FIG. 1A, 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.
Date regue/Date received 2023-02-24
[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 ai 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.
100531 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
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Date regue/Date received 2023-02-24
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.
[0054] 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 reaution 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.
[0055] 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
12
Date regue/Date received 2023-02-24
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.
[0056] 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.
[0057] 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 formed, 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
13
Date regue/Date received 2023-02-24
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
14
Date regue/Date received 2023-02-24
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.
100611 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 (RF) 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.
100621 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 regue/Date received 2023-02-24
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.
100631 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
16
Date regue/Date received 2023-02-24
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 136ai
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 136ai. 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
17
Date regue/Date received 2023-02-24
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.
100661 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).
100671 Referring back to FIGS. EA, 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
18
Date regue/Date received 2023-02-24
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.
[0068] 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.
[0069] 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
19
Date regue/Date received 2023-02-24
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.
[0070] 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 I 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 1526 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 2023-02-24
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.
100721 Following interaction with the streamers 150a, the precursor
material 132a,
plasma forming material 130a, and/or streamers 150a foal' 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.
100731 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
21
Date regue/Date received 2023-02-24
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
22
Date regue/Date received 2023-02-24
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.
[0077] 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.
100781 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
23
Date regue/Date received 2023-02-24
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.
100791 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
Raining 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
24
Date regue/Date received 2023-02-24
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 regue/Date received 2023-02-24
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.
100841 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.
100851 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.
100861 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
204
100871 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 forming 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
26
Date regue/Date received 2023-02-24
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.
100881 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 foimed 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-theimal 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-theimal plasma 250 changes composition along a
distance of
the reaction zone 204
10088.1] 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.
100891 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-
theinial 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
27
Date regue/Date received 2023-02-24
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 regue/Date received 2023-02-24
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 configurationn 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 foiming 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
28
Date regue/Date received 2023-02-24
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-theimal 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 configurationn 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
29
Date regue/Date received 2023-02-24
[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 regue/Date received 2023-02-24
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.
100941 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
350
100951 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 regue/Date received 2023-02-24
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.
100961 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 nun-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 forming
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.
100971 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, (at)
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 (a2) and distance (X3) affect
a first travel
31
Date regue/Date received 2023-02-24
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.
100981 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.
32
Date regue/Date received 2023-02-24
[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-
themial
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.
33
Date regue/Date received 2023-02-24
[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 regue/Date received 2023-02-24
boundary 302a of vessel, and in one embodiment fifth boundary 328* 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.
1001021 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.
34
Date regue/Date received 2023-02-24
[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 regue/Date received 2023-02-24
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 forming
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.
100106] 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 ft:timing
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 (al) with respect to the
second conduit 122;
the second conduit 122 is positioned at a second angle (a7) 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, (al) 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
(a2) 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 (at) 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
36
Date regue/Date received 2023-02-24
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.
1001071 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.
37
Date regue/Date received 2023-02-24
[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
fainting 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.
101011 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.
101021 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
38
Date regue/Date received 2023-02-24
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.
101051 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
39
Date regue/Date received 2023-02-24
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.
[0107] 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 regue/Date received 2023-02-24
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
41
Date regue/Date received 2023-02-24
greater than the critical density and that is transmitted from the plasma
!bulling 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 TM04n). 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
fonned. 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
425
42
Date regue/Date received 2023-02-24
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
43
Date regue/Date received 2023-02-24
zone 504. In such an embodiment, the plasma Ruining 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.
[01171 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,
44
Date regue/Date received 2023-02-24
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.
101201 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 (CJI2n+2, CaHn, CaHn, where n=2
through 6),
nitrogen (N2) and hydrogen (H2) gases.
101211 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" to about 4.58E+06 hr', but can be as low as about 4 hr" to about
400 hr", and
about 400 hr4 to about 4.58e+04 hr". More preferably, the GHSV is about
5.00E+04 hr4to
about 5.00E+05 hr', and most preferably the GHSV is about 7.75E+04 hr' to
about
8.85E+05 hr-4. Specifically, in an embodiment the GHSV is about 8.27E5 hi.'
within the
reaction plasma region 425a.
101221 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 regue/Date received 2023-02-24
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
H3C-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-thermal 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-thermal
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-theimal 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
46
Date regue/Date received 2023-02-24
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
FIG 4
according to, but not limited to, the following reactions:
4 CH, ¨> CH3 + H
(2) CH4 +11 ¨> CH3 +112
(3) CH3 + Cl/3 ¨> C2I16
4 C2H6 ¨> C2/14 + H2
(5) C2H4 CH 2 + H2
(6) C2112 ¨> carbon based material + H2
7 CO2 + H2 C(S) + H20
[0127] 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
47
Date regue/Date received 2023-02-24
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.
101291 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).
101301 For example, the molar ratio of a CH4:112 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
48
Date regue/Date received 2023-02-24
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 H2 content and reduction in the amount of
amorphous
carbon particles. When increasing the H2: 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
H2: 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
49
Date regue/Date received 2023-02-24
relative weight percentages of amorphous particles, semi-graphitic particles,
and nano-
graphene sheets at this molar ratio was found to be about 00/h, about 50%, and
about 50%,
respectively.
[0134] 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 H2 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.
[0135] 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.
[0136] 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 regue/Date received 2023-02-24
[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
51
Date regue/Date received 2023-02-24
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).
[0141] 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 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. 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 forming
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.
[0142] 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
52
Date regue/Date received 2023-02-24
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-thermal 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.
53
Date regue/Date received 2023-02-24
[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 to about 1,000 hrl, but more preferably about 1,000 ht.' to about
10,000 hr-i. 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
1.0,000
Kelvin, more preferably about 500 Kelvin to about 1000 Kelvin.
[0151] 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 + 3112 -> 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
54
Date regue/Date received 2023-02-24
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 regue/Date received 2023-02-24
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
250
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.
101571 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
56
Date regue/Date received 2023-02-24
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-thermal 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
57
Date regue/Date received 2023-02-24
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.
[0163] 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
2.45
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-thermal micro-plasma.
[0164] 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
58
Date regue/Date received 2023-02-24
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.
[0166] 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.
[0167] The flow charts and block diagrams in the Figures illustrate
the architecture,
functionality, and operation of possible implementations of systems, methods,
and computer
59
Date regue/Date received 2023-02-24
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,
01681 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.
101691 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
101701 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 regue/Date received 2023-02-24
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.
61
Date regue/Date received 2023-02-24
