Microwave plasma apparatus and method for treating a feed material utilizing multiple microwave plasma applicators - Patents.com
Patent Information
- Application Number
- JP2024545916
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-02-02
- Filing Date
- 2023-01-26
- Publication Date
- 2025-03-05
Smart Images
Figure 2025505990000001_ABST
Abstract
Description
[Technical field]
[0001] This application is a joint venture of U.S. Provisional Application No. 63 / 267,470 (filed February 2, 2022). No. 6,313,635, the entire disclosure of which is incorporated herein by reference.
[0002] SUMMARY The present disclosure relates generally to microwave plasma devices that utilize multiple microwave plasma applicators within a single device to treat feed materials within a reaction chamber. [Background technology]
[0003] Plasma torches generate and provide a high temperature directed flow of plasma for a variety of purposes. Two main types of plasma torches are induction plasma torches and microwave plasma torches. In general, induction plasma suffers from plasma non-uniformity. This non-uniformity leads to limitations in the ability of induction plasma to process certain materials. Furthermore, there are significant differences between the microwave plasma devices described herein and other plasma generating torches, such as induction plasma. For example, microwave plasma is hotter inside the plasma plume, while induction plasma is hotter outside the plume. In particular, the outer region of induction plasma can reach approximately 10,000K, while the inner process region can only reach approximately 1,000K. This large temperature difference leads to material processing and feeding problems. Furthermore, induction plasma devices cannot process feed materials at a low enough temperature to avoid melting certain feed materials without extinguishing the plasma. Thus, the microwave plasma methods and systems described herein can solve the problems that exist in induction plasma systems.
[0004] Conventional microwave plasma torch systems use a single microwave plasma applicator to generate the microwave plasma. Materials are typically introduced from above the plasma applicator or through one or more openings below the applicator along with the generated plasma. These materials can be used in a variety of applications, including, for example, additive manufacturing and battery technology.
[0005] In a conventional single applicator microwave torch, a plasma is formed from a single applicator by superheating and ionizing the plasma gas, then pumping the plasma gas downward into a reaction chamber, and materials are provided to the plasma for processing. Conventional systems using a single applicator generate approximately 40KW of power integrated into the plasma gas to process materials. Although high power single microwave plasmas are provided, the amount of power of the single microwave plasma saturates at higher throughputs of feed materials. These high temperature plasmas allow for processing of various materials, for example, exposed to or provided to the plasma. One example of such processing is exposing or providing one or more materials of a particular size and shape to the plasma, and then processing or transforming the one or more materials to a different size or shape. However, these plasma systems are used with special tuning for various specific material properties.
[0006] In view of the need to better tailor material properties of final products and the inherent limitations of single applicator microwave plasma efficiency, improved microwave plasma devices and processes are required. Summary of the Invention [Means for solving the problem]
[0007] For the purpose of this summary, certain aspects, advantages, and novel features of the present invention are described herein. Not all advantages are necessarily provided in any particular embodiment of the present invention. Thus, for example, one skilled in the art may embody or implement the present invention to achieve one or more advantages taught herein without necessarily achieving other advantages that may be taught or suggested herein.
[0008] Some embodiments herein relate to a microwave plasma apparatus for processing materials, the microwave plasma apparatus comprising a reaction chamber, a plurality of microwave plasma applicators in communication with the reaction chamber, at least one microwave radiation source generating microwave radiation, at least one waveguide transmitting microwave radiation from the at least one microwave radiation source to the plurality of microwave plasma applicators, and a material delivery system in communication with the reaction chamber.
[0009] In some embodiments, each microwave plasma applicator of the plurality of microwave plasma applicators generates a plasma plume. In some embodiments, the plurality of microwave plasma applicators are positioned such that the plasma plumes generated by each microwave plasma applicator converge to form a compound plasma plume. In some embodiments, each microwave plasma applicator of the plurality of microwave plasma applicators is substantially parallel to the central axis. In some embodiments, each microwave plasma applicator of the plurality of microwave plasma applicators is angled toward the central axis, and each microwave plasma applicator of the plurality of microwave plasma applicators forms an angle between 0 degrees and 90 degrees with the central axis.
[0010] In some embodiments, the apparatus further comprises at least one gas supply system in communication with at least one microwave plasma applicator of the plurality of microwave plasma applicators, In some embodiments, the at least one microwave plasma applicator generates at least one plasma plume when gas is introduced from the at least one gas supply system to the at least one microwave plasma applicator.
[0011] In some embodiments, the microwave plasma apparatus has the same number of microwave radiation sources as the number of microwave plasma applicators and the same number of waveguides as the number of microwave plasma applicators. In some embodiments, the microwave plasma apparatus has half the number of microwave radiation sources as the number of microwave plasma applicators. In some embodiments, the microwave plasma apparatus has half the number of waveguides as the number of microwave plasma applicators.
[0012] In some embodiments, the plurality of microwave plasma applicators comprises two, three, or four microwave plasma applicators. In some embodiments, the plurality of microwave plasma applicators are arranged in a plane with respect to one another. In some embodiments, the plurality of microwave plasma applicators is comprised of three microwave plasma applicators. In some embodiments, each microwave plasma applicator of the three microwave plasma applicators is arranged in a plane at an angle of 120 degrees relative to at least one other microwave plasma applicator of the plurality of microwave plasma applicators. In some embodiments, the plurality of microwave plasma applicators is comprised of four microwave plasma applicators. In some embodiments, each microwave plasma applicator of the four microwave plasma applicators is arranged in a plane at an angle of 90 degrees relative to at least one other microwave plasma applicator of the plurality of microwave plasma applicators. In some embodiments, the plurality of microwave plasma applicators comprises two, three, or four microwave plasma applicators. In some embodiments, each microwave plasma applicator of the two, three, or four microwave plasma applicators is arranged in a plane at an angle of at least one other microwave plasma applicator of the plurality of microwave plasma applicators. At least one of the microwave plasma applicators is disposed in a plane at an angle of about 90 degrees, or about 120 degrees, or about 180 degrees relative to at least one other of the microwave plasma applicators. In some embodiments, the plurality of microwave plasma applicators is disposed in a plane with respect to one another. In some embodiments, the plurality of microwave plasma applicators comprises two microwave plasma applicators. In some embodiments, the plurality of microwave plasma applicators comprises four microwave plasma applicators. In some embodiments, each microwave plasma applicator of the four microwave plasma applicators is disposed in a plane at an angle of 90 degrees relative to at least one other of the plurality of microwave plasma applicators.
[0013] In some embodiments, the material supply system supplies the process material between the multiple microwave plasma applicators. In some embodiments, the reaction chamber has an outlet and the material supply system delivers the process material to the reaction chamber from a position above the outlet. In some embodiments, the reaction chamber has an outlet and the material supply system delivers the process material to the reaction chamber horizontally from below the outlet. In some embodiments, the apparatus further includes an extension tube that confines plasma generated by each microwave plasma applicator of the multiple microwave plasma applicators within the reaction chamber. [Brief description of the drawings]
[0014] The drawings depict exemplary embodiments and are not intended to limit the scope of the disclosure. The systems and methods disclosed herein will be understood by reference to the following description in conjunction with the accompanying drawings, in which:
[0015] [Figure 1] FIG. 1 illustrates an exemplary single applicator microwave plasma system. [Figure 2A] FIG. 2A shows an exemplary single applicator microwave plasma system with a side-feed hopper. [Figure 2B] FIG. 2B illustrates an exemplary single applicator microwave plasma system with a side-feed hopper. [Diagram 3] FIG. 3 illustrates an exemplary single applicator microwave plasma system. [Figure 4] FIG. 4 illustrates an exemplary multi-applicator microwave plasma system having two plasma applicators. [Diagram 5] FIG. 5 illustrates an exemplary multi-applicator microwave plasma system having three plasma applicators. [Figure 6] FIG. 6 illustrates an exemplary multi-applicator microwave plasma system having four plasma applicators. [Figure 7]FIG. 7 illustrates another embodiment of a multi-applicator microwave plasma system having four plasma applicators. [Figure 8] FIG. 8 illustrates another embodiment of a multi-applicator microwave plasma system having four plasma applicators. [Figure 9] FIG. 9 illustrates one embodiment of the downstream portion of a multiple applicator microwave plasma system with an extension tube. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] Although certain preferred embodiments and examples are disclosed below, the subject matter of the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and / or uses, as well as modifications and equivalents thereof. Accordingly, the claims appended hereto or hereafter presented are not limited by any of the specific embodiments described below. For example, in any method or process disclosed herein, the acts or operations in the method or process may be performed in any suitable order and are not necessarily necessarily sequential. The disclosed order is not limited to a specific order. Various operations are described in sequence as multiple separate operations in a manner that may be helpful in understanding some embodiments. However, the order of description does not imply that these operations must be in that order. Also, the structures, systems, and / or devices described herein may be embodied as integrated components or as separate components. For purposes of comparing various embodiments, certain aspects and advantages of these embodiments are described. However, not necessarily all aspects or advantages are achieved by any particular embodiment. Thus, for example, various embodiments may be performed in a manner that achieves or optimizes one or more advantages taught herein without necessarily achieving other aspects or advantages taught or suggested herein.
[0017] Certain exemplary embodiments will now be described to provide a general understanding of the principles of the structure, function, manufacture, and use of the devices and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will appreciate that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments, and the scope of the invention is defined only by the claims. Features illustrated or described in connection with one exemplary embodiment may be combined with features of other embodiments. Such modifications and variations are intended to be within the scope of the present technology.
[0018] Although a single microwave plasma can provide a large amount of power, the amount of power of a single microwave plasma saturates as the throughput of the feed material increases. In some embodiments, possible efficiency improvements can be made by increasing the number and arrangement of plasma applicators in the torch system to increase the throughput of the feed material. Increasing the number of plasma applicators in a single processing zone can increase the amount of power in the plasma without other changes to the device subsystem. Thus, higher system efficiency can be achieved by using multiple plasma torches.
[0019] Single applicator plasma torch systems generally function by using a single plasma applicator to generate a single directional plasma where chemical and / or physical reactions with the feed material occur. Various parameters (e.g., power, residence time, size of the feed material, type of plasma gas, etc.) can be adjusted to process a particular material in a specific manner depending on the desired outcome. One drawback of single applicator microwave plasma source torches is the non-uniform temperature gradient of the plasma generated. This non-uniform gradient, along with other process limitations (e.g., power saturation, plasma size, etc.), can reduce the ability of the single applicator microwave plasma torch to control a particular material synthesis parameter, reducing the efficiency of the microwave plasma system. To overcome these limitations, in some embodiments, plasma torches that utilize multiple microwave plasma applicators are useful. Also, in some embodiments, multiple applicators in the same torch can generate one or more plasmas with more uniform temperature gradients, increased power, and / or more adjustable size, thereby increasing overall process control. In some embodiments, various different geometric configurations of the multiple plasma applicators can provide, for example, a more uniform temperature distribution within the generated plasma and reaction space.
[0020] One advantage of using multiple plasma applicators in the same torch is that it allows for designs that allow for axial injection of material. In some embodiments, axial injection of material can be achieved using piezoelectric droplet makers that can produce droplets with high uniformity in size. Also, in some embodiments, high power microwave plasmas can be used to generate high uniformity temperature gradients. The loom is capable of producing highly uniform molten conditions that can produce highly homogeneous coatings and powders compared to related art.
[0021] In some embodiments, the use of multiple applicators within the same plasma torch enables microwave plasma devices to achieve plasma jet temperatures as high as 8000K, approximately twice the highest known achievable stoichiometric combustion temperature (i.e., 3000K for a hydrogen-oxygen flame). Thus, certain embodiments herein can achieve complete heating of material at higher rates and larger particle sizes over shorter distances than can be achieved using a single plasma oxy-fuel torch.
[0022] Disclosed herein are embodiments of microwave plasma system devices, assemblies, and apparatuses that use multiple microwave plasma applicators. As disclosed herein, multiple microwave plasma systems include systems having multiple microwave plasma applicators. In some embodiments, multiple plasma systems can be used to process materials by introducing materials into one or more of the microwave plasma generated by the multiple plasma applicators, one or more plasma plumes of the multiple plasma applicators, and / or one or more exhausts of the microwave plasma applicators. The feed position can be deflected depending on the desired material processing conditions, since the feed position can affect the residence time and thermal exposure of the material, as well as the latency of the material within one or more of the plasma, plume, and / or exhaust.
[0023] Some embodiments herein are directed to a microwave plasma torch having multiple microwave plasma applicators. In some embodiments, the microwave plasma applicators are arranged planarly relative to each other. In some embodiments, there may be 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 100, 200, 300, 400, 500, or up to 1000 (or any number between the above numbers) microwave plasma applicators, each of which may be arranged planarly relative to each other. In some embodiments, the multiple microwave plasma applicators are arranged planarly and / or symmetrically around a central axis. Also, in some embodiments, each plasma applicator can be positioned relative to the other plasma applicators at an angle of 180 degrees, 150 degrees, 130 degrees, 120 degrees, 90 degrees, 72 degrees, 60 degrees, 45 degrees, 30 degrees, 20 degrees, 15 degrees, 10 degrees, 5 degrees, and / or any angle between these values.
[0024] In some embodiments, a gas supply system can be provided in communication with one or more of the plasma applicators. In some embodiments, a plurality of gas supply systems can be provided, each gas supply system being connected to one of the plurality of plasma applicators. In some embodiments, each of the plurality of plasma applicators is configured to generate a plasma and / or a plasma plume upon introduction of gas from the gas supply system. In some embodiments, the gas in the gas supply system is hydrogen and / or oxygen gas. In other embodiments, the gas supplied is neon, argon, helium, or other inert and / or noble gas. In other embodiments, reactive plasma gases can be used. In some embodiments, methane gas or other hydrocarbons can be used. In some embodiments, nitrogen gas can be used.
[0025] In some embodiments, each microwave plasma applicator generates a microwave plasma plume, and in some embodiments, each plasma applicator generates a plasma plume that extends in a direction substantially parallel to each of the plasma plumes generated from each of the other plasma applicators. The multiple microwave plasma plumes are non-converging, and in some embodiments, the non-converging microwave plasma plumes result in more uniform temperature gradients between, around, above, and / or below the multiple plasma plumes.
[0026] Some embodiments herein are directed to a microwave plasma apparatus having multiple microwave applicators, and in some embodiments, the microwave plasma applicators are tilted away from one another such that plasma generated by the individual microwave plasma applicators do not converge, and in some embodiments, the microwave plasma applicators are tilted toward one another such that plasma generated by the individual microwave plasma applicators converge into a single plasma plume.
[0027] In some embodiments, the microwave plasma applicators are configured to surround a central axis. In some embodiments, the microwave plasma applicators extend parallel to the central axis. In other embodiments, the microwave plasma applicators are tilted toward the central axis. In some embodiments, tilting the microwave plasma applicators toward the central axis directs the plasma generated by the microwave plasma applicators toward the central axis and / or generates a plasma that converges to the central axis. In some embodiments, the angle between the plasma applicator and the central axis is 5 degrees, 10 degrees, 15 degrees, 20 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, or any other angle in the range of 0 degrees to 90 degrees. In some embodiments, tilting the microwave plasma applicators relative to the central axis causes the multiple plasma applicators to generate overlapping microwave plasma plumes at or near the central axis. In some embodiments, when multiple microwave plasmas overlap, they may converge into a single plasma. Also, in some embodiments, the focused single plasma provides desirable properties such as more uniform temperature gradients and higher power compared to microwave plasma generated from a single microwave plasma applicator.
[0028] In some embodiments, the microwave plasma applicator generates one or more plasma plumes. In some embodiments, the microwave plasma applicator generates microwave plasma plumes in a parallel direction. In some embodiments, the parallel microwave plasma plumes can overlap to form a single convergent plasma plume. In other embodiments, the parallel microwave plasma plumes do not overlap. In some embodiments, the overlapping plasmas overlap and converge into a single, convergent or combined plasma plume. A convergent or combined plasma plume is advantageous in that such a combination results in a larger, more powerful, and more homogeneous plasma. Such a larger plasma can enable faster throughput of feed material with higher efficiency, leading to reduced costs and time associated with processing.
[0029] In some embodiments, each microwave plasma applicator is connected to an individual waveguide such that there are an equal number of waveguides and microwave plasma applicators, and in some embodiments, each waveguide directs microwave radiation from a microwave radiation source to a plasma applicator, and in some embodiments, each waveguide is connected to multiple microwave plasma applicators, and in some embodiments, each waveguide is connected to a single microwave plasma applicator.
[0030] In some embodiments, the microwave radiation is generated by one or more microwave sources. Also, in some embodiments, a single microwave power source may include multiple plasma sources. In some embodiments, a single microwave power source provides microwave radiation to one of the plasma applicators, and in other embodiments, a single microwave power source provides microwave radiation to two or more of the plasma applicators, and in some embodiments, a single microwave power source provides microwave radiation to all of the plasma applicators.
[0031] In some embodiments, each microwave radiation source is connected to an individual waveguide that supplies the generated microwave radiation to the microwave plasma applicator, while in other embodiments, a single microwave radiation source is connected to two or more waveguides, each waveguide providing microwave radiation to one of the one or more microwave plasma applicators.
[0032] In some embodiments, the microwave source generates a frequency between about 500 megahertz (500 MHz) and about 100 gigahertz (100 GHz). Also, in some embodiments, the microwave source has a nominal generator rating of about 915 MHz, although the generator rating is not limited to such values. In some embodiments, the microwave source has an output power between about 5 kW and about 75 kW, although the output power is not limited to such values.
[0033] Some embodiments herein are directed to a microwave plasma apparatus for processing materials. In some embodiments, the apparatus includes a reaction chamber. In some embodiments, the reaction chamber is in communication with a plurality of plasma applicators. In some embodiments, the apparatus includes at least one waveguide for directing microwave radiation from at least one microwave radiation source to the plurality of plasma applicators. In some embodiments, a gas supply is in fluid communication with the plurality of plasma applicators. In some embodiments, the gas supply is configured to supply at least one gas to each plasma applicator of the plurality of plasma applicators, each plasma applicator generating a plasma plume upon being supplied with the at least one gas. In some embodiments, a material supply system is in communication with the reaction chamber, the material supply system directing process materials into the reaction chamber.
[0034] In some embodiments, the microwave plasma apparatus is configured for modular assembly. Also, in some embodiments, one or more microwave plasma applicators may be added to or removed from the plasma apparatus. Also, in some embodiments, one or more of the microwave plasma applicators may be removed between reaction processes. Such a modular configuration provides flexible use and application of the microwave plasma system.
[0035] In some embodiments, a gas injector is in communication with each plasma applicator. In some embodiments, the gas injector directs each plasma plume in a direction substantially parallel to an axis of the plasma chamber, such as the central axis. In some embodiments, the gas injector is used to ensure that the plasma generated from each of the microwave plasma applicators is not focused. Alternatively, in other embodiments, the gas injector can be used to focus the multiple generated plasmas.
[0036] Some embodiments herein relate to extending a microwave plasma generated by a microwave plasma applicator within a microwave plasma torch. Also, in some embodiments, extending the microwave plasma includes obtaining a plasma of sufficient length to process a feed material to produce a material having desired material properties. Also, in some embodiments, a microwave plasma apparatus according to embodiments herein may include an extension tube extending downwardly into a reaction chamber of the microwave plasma apparatus, which can extend the length of the extension tube that confines and directs the microwave plasma. Also, in some embodiments, the extension tube can extend a longer microwave plasma or multiple plasmas within the apparatus. The energy and power provided by the multiple plasma applicators can be concentrated to form the plasma, and in some embodiments, the extension tube can improve conditioning of the material by concentrating the energy and power of the multiple plasma applicators.
[0037] In conventional microwave plasma devices, the plasma is formed by superheating and ionizing the plasma gas and then directing the plasma downward into a reaction chamber where material is provided to the plasma and processed into a material. In conventional microwave plasma devices, the length of the plasma, plasma plume, or plasma exhaust is limited. For example, as the plasma extends downward away from the microwave plasma applicator in the reaction chamber, the plasma is cooled by the surrounding gas, which results in free electrons in the plasma recombining with the plasma gas atoms and terminating the plasma. Furthermore, as the plasma moves away from the power source, there is a lack of energy to the plasma gas, which causes the plasma to recombine and become a gas. Furthermore, the superheated plasma is less dense than the surrounding gas, and the plasma naturally rises above the surrounding gas, thus limiting the length of the plasma in the device. Furthermore, in conventional devices, the plasma does not maintain a fixed shape or volume, so the length and shape of the generated plasma is highly dynamic.
[0038] To address these limitations in plasma length and stability, the apparatus described herein employs extension tubes that extend downward from the microwave plasma applicators into the reaction chamber. In some embodiments, the extension tubes can concentrate the energy from the microwave plasma applicators into a smaller volume and extend and direct the plasma to generate plasmas longer than possible with conventional microwave plasma apparatus. In some embodiments, the length of the plasmas can be adjusted or changed by configuring one or more of the following parameters: power, plasma gas flow, gas type, extension tube material, reaction chamber or extension tube insulation level, extension tube coating level, extension tube geometry (e.g., tapered / stepped).
[0039] In some embodiments, the extension tubes described herein can extend downward into the reaction chamber of the microwave plasma device, and in some embodiments, the downward extension length of the extension tube can be at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 100%, or any value between these values, of the length of the reaction chamber.
[0040] In some embodiments, the reaction chamber may further include an exhaust port. In some embodiments, the exhaust port may be located below the multiple microwave plasma applicators. In some embodiments, the exhaust port may be positioned to surround the multiple or combined plasmas or plasmas. In some embodiments, the plasma plume of the multiple plasma applicators may extend beyond the exhaust port. In some embodiments, the material supply system may be configured to supply material from above the exhaust port. In other embodiments, the material supply system may be configured to supply material from below the exhaust port.
[0041] (Microwave plasma device) FIG. 1 illustrates an embodiment of a microwave plasma torch 100 that can be used to produce materials according to some embodiments of the present disclosure. In some embodiments, the materials are The material is introduced into the microwave plasma 104 via the material inlet 102. In some embodiments, a blowing gas flow and / or a sheath flow can be injected into the microwave plasma applicator 105 to create flow conditions within the plasma applicator prior to ignition of the plasma 104 via the microwave radiation source 106. In some embodiments, the blowing flow and the sheath flow are both axisymmetric and laminar, while in other embodiments the gas flow is swirling. In some embodiments, the material may be introduced into the microwave plasma torch 100, and the material may be blown by a gas flow that delivers the material to the plasma 104.
[0042] As mentioned above, the gas flow can include gases that fall into the noble gas column of the periodic table, such as helium, neon, argon, etc. Also, while the above gases can be used, various gases can be used depending on the desired materials and processing conditions. In some embodiments, physical and / or chemical transformations can be performed on the materials in the microwave plasma 104. The inlet 102 can be used to introduce process gases and to blow and accelerate the materials toward the plasma 104. Also, in some embodiments, a second gas flow can be generated to coat the inner walls of the plasma applicator 104 and the reaction chamber 110 to protect these structures from melting due to thermal radiation from the plasma 104.
[0043] Additionally, various parameters of the microwave plasma 104 generated by the plasma applicator 105 may be adjusted manually or automatically to achieve the desired material. These parameters include, for example, power, plasma gas flow rate, type of plasma gas, presence or absence of extension tubes, extension tube material, reaction chamber or extension tube insulation level, extension tube coating level, extension tube geometry (e.g., tapered / stepped), feed material size, feed material insertion rate, feed material inlet location, feed material inlet orientation, number of feed material inlets, plasma temperature, residence time, and cooling rate. Additionally, the resulting material exits the plasma and enters the enclosed chamber 112 where the material is quenched and then collected.
[0044] In some embodiments, material is injected after the microwave plasma applicator for processing in the "plume" or "exhaust" of the microwave plasma torch. Thus, the microwave plasma torch plasma is engaged at or downstream of the exit end of the plasma torch core tube 108. Also, in some embodiments, an adjustable downstream feed allows the feed material to be engaged with the downstream plasma plume at a temperature suitable for optimal melting of the feed material through precise targeting of temperature levels and residence times. Adjusting the inlet location and plasma characteristics can further customize the material properties. Additionally, in some embodiments, the length of the plasma plume can be adjusted by adjusting power, gas flow rates, pressure, and equipment configuration (e.g., introducing extension tubes).
[0045] In some embodiments, the feed configuration includes one or more individual feed nozzles that surround the plasma plume, and the feed material can be introduced into the plasma from any direction, and can be fed from 360 degrees around the plasma, depending on the placement and orientation of the inlets 102. Furthermore, by adjusting the placement of the inlets 102, material can be introduced into the plasma at specific locations along the length of the plasma 104 where specific temperatures can be measured and residence times estimated to obtain desired material properties.
[0046] In some embodiments, the angle of the inlet 102 relative to the plasma 104 may be adjusted such that the feed material is injected at any angle relative to the plasma 104. For example, the inlet 102 may be adjusted such that the material is injected at about 0 degrees, about 5 degrees, about 10 degrees, about 15 degrees, about 20 degrees, about 25 degrees, about 30 degrees, about 35 degrees, about 40 degrees, about 45 degrees, about 50 degrees, about 55 degrees, about The beam may be adjusted to be injected into the plasma at an angle of 60 degrees, about 65 degrees, about 70 degrees, about 75 degrees, about 80 degrees, about 85 degrees, about 90 degrees, or an angle between any of these angles.
[0047] In some embodiments, the downstream injection method may be implemented using a downstream vortex or quench, where a downstream vortex is an additional vortex component that can be introduced downstream from the plasma applicator to keep the powder away from the walls of the applicator 105, reaction chamber 110, and / or extension tube 114.
[0048] In some embodiments, the length of the reaction chamber 110 of the microwave plasma apparatus can be about 1 foot, about 2 feet, about 3 feet, about 4 feet, about 5 feet, about 6 feet, about 7 feet, about 8 feet, about 9 feet, about 10 feet, about 11 feet, about 12 feet, about 13 feet, about 14 feet, about 15 feet, about 16 feet, about 17 feet, about 18 feet, about 19 feet, about 20 feet, about 21 feet, about 22 feet, about 23 feet, about 24 feet, about 25 feet, about 26 feet, about 27 feet, about 28 feet, about 29 feet, about 30 feet, or any length in between these lengths.
[0049] Also, in some embodiments, the length of the plasma 104 can be extended by adjusting various process conditions and equipment configurations to about 1 foot, about 2 feet, about 3 feet, about 4 feet, about 5 feet, about 6 feet, about 7 feet, about 8 feet, about 9 feet, about 10 feet, about 11 feet, about 12 feet, about 13 feet, about 14 feet, about 15 feet, about 16 feet, about 17 feet, about 18 feet, about 19 feet, about 20 feet, about 21 feet, about 22 feet, about 23 feet, about 24 feet, about 25 feet, about 26 feet, about 27 feet, about 28 feet, about 29 feet, about 30 feet, or any length in between these lengths.
[0050] 2A and 2B show an exemplary microwave plasma torch with a side feed hopper that allows for downstream feeding. Thus, in this embodiment, material is injected into the rear of the microwave plasma torch applicator for processing in the "plume" or "exhaust" of the microwave plasma torch. Thus, the plasma of the microwave plasma torch is engaged at the exit end of the plasma torch, allowing for downstream feeding of the feed material as opposed to top feeding (or upstream feeding). This downstream feeding advantageously extends the life of the torch since the hot zone is protected indefinitely from any material deposits on the walls of the hot zone liner. Furthermore, this allows for the plasma plume to be engaged downstream at a temperature suitable for optimal melting of the powder through precise targeting of temperature levels and residence times. For example, there is the ability to adjust the length of the plume with the pressure in the quenching vessel that contains the microwave powder, gas flow, and plasma plume.
[0051] In general, downstream feeding can utilize two main hardware configurations to establish a stable plasma plume, such as the annular torch described in US Patent Publication No. 2018 / 0297122 (hereby incorporated by reference in its entirety) and the vortex torch described in US Patent No. 8,748,785 (hereby incorporated by reference in its entirety) and US Patent No. 9,932,673 (hereby incorporated by reference in its entirety). A feeding system closely coupled to the plasma plume at the exit of the plasma torch can be used to feed the powder axisymmetrically to maintain process homogeneity.
[0052] Other feed configurations include one or more independent feed nozzles surrounding the plasma plume. The powder can be introduced into the plasma from any direction, at a specific location, 360 degrees around the plasma. The powder can also be introduced into the plasma at any direction, at any location around the length of the plasma plume. The particles can be introduced into the plasma at specific locations along the length, allowing temperature measurements at those locations and an estimate of residence time for sufficient melting of the particles, and the molten particles exit the plasma into a sealed chamber where they are quenched and then collected.
[0053] The feed material 214 can be introduced into the microwave plasma applicator 202. The hopper 206 can be used to store the feed material 214 before delivering it to the microwave plasma applicator 202, the plume and / or the exhaust 218. The feed material 214 can be injected at any angle relative to the longitudinal direction of the plasma applicator 302, including angles of about 5 degrees, about 10 degrees, about 15 degrees, about 20 degrees, about 25 degrees, about 30 degrees, about 35 degrees, about 40 degrees, about 45 degrees, about 50 degrees, about 55 degrees. In some embodiments, the material can be injected at an angle greater than 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or 55 degrees. Also, in some embodiments, the material can be injected at an angle less than 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or 55 degrees. Also, in an alternative embodiment, the material may be injected along the longitudinal axis of the plasma torch.
[0054] Microwave radiation can be introduced into the plasma applicator 202 via a waveguide 204. A feed material 214 is fed into the plasma chamber 210 and positioned to contact the plasma generated by the plasma applicator 202. The feed material melts upon contact with the plasma, plasma plume, or plasma exhaust 218. The feed material 214 cools and solidifies while in the plasma chamber 210 and is then collected in a container 212. Alternatively, the feed material 214 can exit the plasma chamber 210 through an outlet 212 while in the molten phase and cool and solidify outside the plasma chamber. Also, in some embodiments, a quench chamber with or without positive pressure may be used. The embodiments of Figures 2A and 2B are described separately from Figure 1, but similar features and conditions to the embodiment of Figure 1 can be used.
[0055] (Multiple microwave plasma applicator configurations) Figure 3 illustrates a single microwave plasma applicator configuration that may be used in a microwave plasma torch according to one embodiment. In a single microwave plasma applicator torch, a single applicator 302 generates a microwave plasma 304. The single plasma applicator system illustrated in Figure 3 corresponds to the schematic diagram of the applicator system illustrated in Figures 1-2B.
[0056] 4 illustrates one embodiment of a multiple plasma applicator system. In some embodiments, the multiple applicator plasma system is comprised of two microwave applicators 402. The microwave plasma applicators 402 are capable of generating a microwave plasma 404 as described above. In some embodiments having two microwave plasma applicators 402, each microwave plasma applicator is aligned with respect to a central axis 406. Also, in some embodiments, the microwave plasma applicators 402 are arranged planar to one another such that they are substantially parallel to the central axis 406.
[0057] FIG. 5 illustrates one embodiment of a multiple plasma applicator system. In some embodiments, the multiple plasma applicator system is comprised of three microwave plasma applicators 502. In some embodiments, each microwave plasma applicator 502 can generate a microwave plasma plume 504. In some embodiments, each microwave plasma plume 504 converges to form a compound plasma at or near a central axis 506. In some embodiments, each microwave plasma plume 504 does not converge or overlap, instead, each generated microwave plasma plume 504 is parallel to one another. Also, in some embodiments, the three microwave plasma applicators 502 can generate a microwave plasma plume 504. In some embodiments, each microwave plasma plume 504 converges to form a compound plasma at or near a central axis 506. In some embodiments, each microwave plasma plume 504 does not converge or overlap, instead, each generated microwave plasma plume 504 is parallel to one another. The applicators 502 are arranged about a central axis 506. In some embodiments, each microwave plasma applicator 502 is arranged planar with respect to the other microwave plasma applicators 502.
[0058] FIG. 6 illustrates one embodiment of a multiple microwave plasma applicator system. In some embodiments, the multiple plasma applicator system is comprised of four microwave plasma applicators 602. In some embodiments, each microwave plasma applicator 602 can generate a microwave plasma plume 604. In some embodiments, each microwave plasma plume 604 converges to form a compound plasma. In some embodiments, each microwave plasma plume 604 does not converge or overlap, instead, each generated microwave plasma plume is parallel to each other. Also, in some embodiments, each of the four microwave plasma applicators 602 is disposed around a central axis 606. In some embodiments, each of the microwave plasma applicators 602 is parallel to the central axis 606.
[0059] 7 illustrates one embodiment of a multiple plasma applicator system. In some embodiments, the multiple plasma applicator system is comprised of four microwave plasma applicators 702. In some embodiments, each microwave plasma applicator 702 can generate a microwave plasma plume 704. In some embodiments, the feed material 706 can be moved or fed between the applicators 702. In some embodiments, the feed material 706 is introduced from above the microwave plasma applicators. In other embodiments, the feed material 706 is introduced horizontally relative to the microwave plasma applicators 702.
[0060] FIG. 8 illustrates an embodiment of a multiple plasma applicator system. In some embodiments, the multiple plasma applicator system is comprised of four microwave plasma applicators 802. In some embodiments, each microwave plasma applicator 802 can generate a microwave plasma plume 804. In some embodiments, each microwave plasma applicator is disposed around a central axis 808. The microwave plasma applicators 802 can be tilted relative to the central axis. As described above, each microwave plasma applicator 802 can be tilted toward or away from the central axis 808 such that the microwave plasma applicator 802 and the central axis 808 form a particular angle. In some embodiments, the angle between each microwave plasma applicator 802 and the central axis 808 can be between 0 degrees and 90 degrees. In some embodiments, the microwave plasma applicator 802 can be tilted toward the central axis 808 to focus the plasma exhaust / plume 804 at or near the central axis 808. In some embodiments, the feed material 806 can be moved or fed between the applicators 802. In some embodiments, the feed material 806 is introduced from above the microwave plasma applicators. In other embodiments, the feed material 806 is introduced horizontally relative to the microwave plasma applicators 802. Also, in some embodiments, as the feed material 806 is introduced between the plasma applicators 802, the feed material contacts each of the plasma plumes 804. Also, in some embodiments, the tilt of the plasma applicators 802 can cause the plasma plumes 804 to converge and form a compound plasma. In some embodiments, the feed material 806 can be introduced between the plasma applicators 802 to contact the compound plasma.
[0061] 9 illustrates one embodiment of a multiple plasma applicator system. In some embodiments, the multiple plasma applicator system can consist of four microwave plasma applicators 902. In some embodiments, each microwave plasma applicator The microwave plasma applicators 902 can be configured to generate a microwave plasma plume 904. In some embodiments, each microwave plasma applicator 902 is disposed about a central axis 908. The microwave plasma applicators 902 can be tilted toward the central axis 908. As described above, each microwave plasma applicator 902 can be tilted toward or away from the central axis 908 to form an angle between the microwave plasma applicator 902 and the central axis 908. In some embodiments, the angle between each microwave plasma applicator 902 and the central axis 908 can be between 0 degrees and 90 degrees. In some embodiments, tilting the microwave plasma applicators 902 toward the central axis 908 can reduce the plasma exhaust / plume. 904 can converge. In some embodiments, the feed material 910 can be directed or fed between the applicators 902. In some embodiments, the feed material 910 is introduced from above the microwave plasma applicators. In other embodiments, the feed material 910 is introduced horizontally relative to the microwave plasma applicators 902. In some embodiments, when the feed material 910 is introduced between the plasma applicators 902, the feed material contacts each of the plasma plumes 904. In some embodiments, the tilt of the plasma applicators 902 can cause the plasma plumes 904 to converge and form a compound plasma. In some embodiments, the feed material 910 can be introduced between the plasma applicators 902 to contact the compound plasma.
[0062] In some embodiments, the extension tube 906 may extend into the reaction chamber and surround and guide the plasma exhaust and / or exhaust 904. In some embodiments, the extension tube may be used with a single microwave plasma applicator and one microwave plasma. In some embodiments, the extension tube may be used with multiple microwave plasma applicators and one or more microwave plasmas. In some embodiments, the extension tube 906 extends downward from the microwave plasma applicator 902 into the reaction chamber. In some embodiments, the extension tube 906 may also focus the energy from the microwave power source into a smaller volume to extend the plasma longer than is possible with conventional microwave plasma devices. In some embodiments, the length of the plasma may be adjusted or changed by setting one or more of the following parameters: power, plasma gas flow, type of gas, extension tube material, insulation level of the reaction chamber or extension tube, coating level of the extension tube, and extension tube geometry (e.g., tapered / stepped).
[0063] In some embodiments, the extension tube 906 has one or more cylindrical volumes that the extension tube extends downward into the reaction chamber, with each successive cylindrical volume having a step shape such that the diameter of the successive cylindrical volumes is greater than the previous cylindrical volume as the extension tube extends downward into the reaction chamber. Also, in some embodiments, the extension tube 910 has a conical shape that tapers radially outward as it extends downward into the reaction chamber. Also, in some embodiments, the extension tube 910 may have a double conical shape, with a first conical shape tapering radially outward as it extends downward into the reaction chamber, and a second conical shape that is an inverse mirror image of the first conical shape, is connected to the end of the first conical shape, and tapers radially inward as it extends downward into the reaction chamber, as shown in FIG. Also, in some embodiments, the extension tube 910 has a single cylindrical volume. Also, in some embodiments, a feed inlet allows feed material to be inserted into the extension tube 906.
[0064] In some embodiments, the extension tube is about 1 foot in length, and in some embodiments, the extension tube is about 1 inch, about 2 inches, about 3 inches, about 4 inches, about 5 inches, about 6 inches, about 7 inches, about 8 inches, about 9 inches, about 10 inches, about 11 inches in length. , about 1 foot, about 2 feet, about 3 feet, about 4 feet, about 5 feet, about 6 feet, about 7 feet, about 8 feet, about 9 feet, about 10 feet, about 11 feet, about 12 feet, about 13 feet, about 14 feet, about 15 feet, about 16 feet, about 17 feet, about 18 feet, about 19 feet, about 20 feet, about 21 feet, about 22 feet, about 23 feet, about 24 feet, about 25 feet, about 26 feet, about 27 feet, about 28 feet, about 29 feet, about 30 feet, or any length in between these lengths.
[0065] In some embodiments, the material particles are exposed to a temperature distribution in the microwave plasma of 4,000-8,000 K. In some embodiments, the particles are exposed to a temperature distribution in the microwave plasma of 3,000-8,000 K. In some embodiments, one or more temperature sensors can be positioned in the microwave plasma torch to determine the temperature distribution of the plasmas.
[0066] (Microwave Plasma Treatment) In microwave plasma processing, materials are bubbled into an inert and / or reducing gas environment and may also be injected into the microwave plasma, microwave plasma plume, or microwave plasma exhaust. When injected into the high temperature plasma (or plasma plume or exhaust), the material undergoes physical and / or chemical transformation (e.g., spheroidization). The resulting material is discharged into a chamber filled with an inert gas and pumped into a hermetically sealed drum for storage. The process may be carried out at atmospheric pressure or at partial vacuum or pressures slightly above atmospheric pressure.
[0067] In alternative embodiments, the process can be performed in low, medium, or high vacuum environments. The process can also be performed batchwise or continuously, with drums being replaced as they are filled with processed material. By controlling process parameters such as cooling gas flow rate, residence time, plasma conditions, and cooling gas composition, various material properties can be controlled.
[0068] Also, adjusting the residence time of the particles within the hot zone of the plasma can provide control over the resulting material properties. That is, the time the particle is exposed to the plasma determines the degree of melting of the material particle (i.e., the surface of the particle is melted compared to the innermost portion or core of the particle). The residence time can be altered by adjusting such operating variables as particle injection rate and flow rate (as well as conditions such as laminar or turbulent flow) within the hot zone. Also, the equipment can be modified to adjust the residence time. For example, the residence time can be adjusted by changing the cross-sectional area of the plasma, e.g., by stretching the plasma. In some embodiments, stretching the plasma includes incorporating an extension tube into the microwave plasma device.
[0069] (Other embodiments) In the above specification, the present invention has been described with reference to specific embodiments. However, various modifications and changes can be made without departing from the broader technical spirit and scope of the present invention. Therefore, the specification and drawings should be regarded in an illustrative rather than a restrictive sense.
[0070] Indeed, while the invention has been disclosed in the context of certain embodiments and examples, it will be appreciated by those skilled in the art that the invention extends beyond the specifically disclosed embodiments to other alternative embodiments and / or uses of the invention and to obvious modifications and equivalents thereof. Also, while several variations of the embodiments of the invention have been shown and described in detail, it will be understood by those skilled in the art based on this disclosure that other modifications can be made which are within the scope of the invention. It will be readily apparent to those skilled in the art that various combinations or subcombinations of the specific features and aspects of the embodiments are also possible and still fall within the scope of the present invention. Also, various features and aspects of the disclosed embodiments can be combined with or substituted for one another to form various aspects of the disclosed inventive embodiments. Any method disclosed herein does not have to be performed in the order recited. Thus, the scope of the invention disclosed herein is not limited by the specific embodiments described above.
[0071] The systems and methods of the present disclosure each have several innovative aspects, no single one of which is solely related to or necessary for the desired attributes disclosed herein. The various features and processes described above can be used independently of one another or can be combined in various ways. All possible combinations and subcombinations thereof are within the scope of the present disclosure.
[0072] Certain features described herein in the context of individual embodiments may be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, even if features are described as functioning in a particular combination and are initially claimed as such, one or more features from the claimed combination may, in some cases, be deleted from the combination, and the claimed combination may be a subcombination or a variation of the subcombination. Additionally, no single feature or features are essential or essential to any embodiment.
[0073] Conditional language used herein, such as "can," "can be," "may," "may," "for example," and the like, generally means that some embodiments include some features while other embodiments do not include some features, unless specifically stated otherwise or understood otherwise within the context in which it is used. Thus, such conditional language does not generally intend that features, elements, and / or steps are in any way essential to one or more embodiments, or that one or more embodiments necessarily include logic for determining whether or not those features, elements, and / or steps should be included or performed in any particular embodiment, with or without manual input or prompting. The terms "comprise," "include," "have," and the like, are synonymous and are used inclusively, open-ended, and do not exclude additional elements, features, acts, operations, and the like. Additionally, the term "or" is used in its inclusive sense (not exclusive), and thus, for example, when used to connect a list of elements, the term "or" means one, some, or all of the elements in the list. Additionally, the numerals meaning "a" and the phrase "said" referring to such numerals as used in this application and the appended claims shall mean "one or more" or "at least one" unless otherwise specified. Similarly, although operations are depicted in the figures in a particular order, such operations need not be performed in the particular order depicted, or in sequential order, or all depicted operations need not be performed to achieve desirable results. Additionally, the figures may generally depict one or more exemplary processes in the form of a flow chart. However, other operations not depicted may be incorporated into the generally depicted exemplary methods and processes. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the depicted operations. Additionally, operations may be reordered in other embodiments. In some circumstances, multitasking and parallel processing may be employed as appropriate.Furthermore, the separation of various system components in the above embodiments does not require such separation in all embodiments, and the program components and methods described may be modified without departing from the spirit and scope of the present invention. The system may generally be integrated into a single software product or packaged into multiple software products. Moreover, other embodiments are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order to achieve desirable results.
[0074] Furthermore, the methods and apparatus described herein are susceptible to various modifications and alternative forms, specific examples of which are illustrated and described in detail herein. However, the present invention should not be limited to the specific forms or methods disclosed, but rather, the present invention covers all modifications, equivalents, and alternatives that fall within the spirit and scope of the various implementations described and the appended claims. Furthermore, any particular feature, aspect, method, property, characteristic, quality, attribute, element, etc., disclosed herein in connection with an implementation or embodiment may also be employed in all other implementations or embodiments described herein. Any method disclosed herein need not be performed in the order recited. The methods disclosed herein may include specific actions performed by a user. However, the methods may include any third-party instructions for their operation, either explicitly or implicitly. The scope of the disclosure herein encompasses various overlaps, partial ranges, and combinations thereof. Words such as "up to," "at least," "greater than," "less than," "between," and the like, include the recited numbers. Numbers marked with terms such as "about" or "approximately" are inclusive of the recited number and are to be interpreted according to the context of use (e.g., as precisely as reasonably possible under the circumstances, e.g., ±5%, ±10%, ±15%, etc.). For example, "about 3.5 mm" means " In addition, terms followed by terms such as "substantially" include the term in question. "Constant" shall be interpreted according to the context of use (e.g., as much as reasonably possible under the circumstances). For example, "substantially constant" includes "constant." Unless otherwise specified, all measurements are made at standard conditions, including temperature and pressure.
[0075] In this specification, the phrase "at least one of" a list of items includes a single item and any combination of the items. For example, "at least one of A, B, and C" includes "A", "B", "C", "A and B", "A and C", "B and C", and "A, B and C". In addition, the conjunction in the phrase "at least one of X, Y, and Z" is understood in the context in which it is generally used to mean that the items, terms, etc. are at least one of X, Y, and Z, unless otherwise specified. Thus, such conjunction generally does not mean that at least one X, at least one Y, and at least one Z are required in an embodiment. In addition, the headings in this specification are for convenience only and do not necessarily affect the scope or meaning of the devices and methods disclosed herein.
[0076] Thus, the scope of the claims is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the present disclosure and the principles and novel features disclosed herein.
Claims
1. 1. A microwave plasma device for processing a material, comprising: A reaction chamber; a plurality of microwave plasma applicators in communication with the reaction chamber; at least one microwave radiation source for generating microwave radiation; at least one waveguide that transmits the microwave radiation from the at least one microwave radiation source to the plurality of microwave plasma applicators; a material supply system in communication with the reaction chamber; A microwave plasma device comprising:
2. 2. The microwave plasma device of claim 1, wherein each microwave plasma applicator of the plurality of microwave plasma applicators generates a plasma plume.
3. The microwave plasma device of claim 2 , wherein the plurality of microwave plasma applicators are arranged so that the plasma plumes generated by each microwave plasma applicator do not converge.
4. 3. The microwave plasma device of claim 2, wherein the plurality of microwave plasma applicators are positioned such that the plasma plumes generated by each microwave plasma applicator converge to form a compound plasma plume.
5. 3. The microwave plasma apparatus of claim 2, wherein each microwave plasma applicator of the plurality of microwave plasma applicators is oriented in a direction substantially parallel to a central axis.
6. each microwave plasma applicator of the plurality of microwave plasma applicators is angled toward a central axis; Each of the microwave plasma applicators of the plurality of microwave plasma applicators forms an angle between 0 degrees and 90 degrees with the central axis.
3. The microwave plasma device according to claim 2.
7. 10. The microwave plasma apparatus of claim 1 further comprising at least one gas supply system in communication with at least one microwave plasma applicator of said plurality of microwave plasma applicators.
8. 8. The microwave plasma apparatus of claim 7, wherein the at least one microwave plasma applicator generates at least one plasma plume when gas is introduced from the at least one gas supply system to the at least one microwave plasma applicator.
9. 2. The microwave plasma apparatus of claim 1, wherein the microwave plasma apparatus comprises a number of microwave radiation sources equal to the number of the microwave plasma applicators, and a number of waveguides equal to the number of the microwave plasma applicators.
10. 2. The microwave plasma apparatus of claim 1, wherein the microwave plasma apparatus has half the number of microwave radiation sources as the number of the microwave plasma applicators.
11. The microwave plasma device has half the number of microwave plasma applicators.
2. The microwave plasma device according to claim 1, further comprising a waveguide.
12. 2. The microwave plasma device of claim 1, wherein the plurality of microwave plasma applicators comprises two, three, or four microwave plasma applicators.
13. 13. The microwave plasma apparatus of claim 12, wherein each of the two, three, or four microwave plasma applicators is disposed in a plane at an angle of about 90 degrees, about 120 degrees, or about 180 degrees relative to at least one other microwave plasma applicator.
14. 2. The microwave plasma device according to claim 1, wherein the microwave plasma applicators are arranged on a plane relative to one another.
15. 2. The microwave plasma apparatus according to claim 1, wherein the plurality of microwave plasma applicators comprises two microwave plasma applicators.
16. 2. The microwave plasma apparatus of claim 1, wherein the plurality of microwave plasma applicators comprises four microwave plasma applicators.
17. 17. The microwave plasma apparatus of claim 16, wherein each microwave plasma applicator of the four microwave plasma applicators is disposed in a plane at a 90 degree angle relative to at least one other microwave plasma applicator of the plurality of microwave plasma applicators.
18. The microwave plasma apparatus of claim 1 , wherein the material supply system supplies process material between the plurality of microwave plasma applicators.
19. the reaction chamber having an outlet; The material delivery system delivers process material horizontally below the outlet into the reaction chamber.
2. The microwave plasma device according to claim 1.
20. 2. The microwave plasma apparatus according to claim 1, further comprising an extension tube for confining plasma generated by each of the plurality of microwave plasma applicators within the reaction chamber.