Plasma reactors and plasma chemical reactions

Abstract

We provide systems and technologies for performing plasma chemical reactions, offering various improvements. [Solution] A method and device are provided for stimulating endothermic reactions in a gas phase with a highly active barrier by nanosecond pulsed discharge. This can be used, for example, for CO2 functionalization of methane, H2S dissociation, hydrogen and synthesis gas production, ammonia synthesis and dissociation, etc. Several embodiments provide a plasma chemical reactor with nanosecond pulsed discharge generation, comprising one or more cylindrical channels 900 having a gas injection and gas exhaust system, a high-voltage positive electrode 902 and a high-voltage negative electrode 901 in each channel, and a gas swirling system in each channel for increasing the local tangential gas velocity near the electrode ends, the frequency of pulsed discharge generation being f, and the tangential gas velocity being f × 5 × 10 -3 Faster than m / s

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims priority to U.S. Provisional Patent Application No. 63 / 061939, filed on 6 August 2020, the entire contents of which are incorporated herein by reference.

[0002] This disclosure provides methods and devices for stimulating endothermic reactions in a gas phase with a highly active barrier by nanosecond pulsed discharge, relating to the field of chemistry. These can be used, for example, in the CO2 functionalization of methane, H2S dissociation, hydrogen and synthesis gas production, ammonia synthesis and dissociation, and the like. Some embodiments include methods and devices relating to stimulating plasma chemical reactions by nanosecond pulsed discharge in the presence of a gas flow. [Background technology]

[0003] Plasma can be seen as a powerful tool for facilitating chemical reactions with high activation energies, for example, in the production of synthetic natural gas and the conversion of CO2 and H2S. Plasma-based technologies can generate plasma chemical reactions that produce non-equilibrium plasma by utilizing barrier discharges and pulsed discharges, electric arcs, or microwave discharges. The name non-equilibrium plasma comes from the fact that gas molecules may remain relatively cold (the temperature of the gas molecules may not rise or may not rise significantly), while electrons in the plasma have enough energy to dissociate and ionize the molecules.

[0004] Plasma parameters for generating plasma chemical reactions can be selected to reduce energy consumption while increasing the yield of the desired product. To stimulate a direct chemical reaction, the plasma can dissociate or excite reagent molecules to generate radicals or other active particles, which then react with each other to produce the desired product.

[0005] Various techniques for producing such reactions are described herein.

[0006] In the first case, source molecules can be dissociated by direct collision with electrons that have sufficient energy. In this case, a key property of the plasma is the electric field voltage, and more specifically, the ratio of the electric field voltage to the gas concentration. This ratio determines whether the energy gained by electrons in the electric field during collisions with gas molecules is sufficient for the desired process of forming radicals or active particles.

[0007] Such techniques can be used to generate non-equilibrium plasmas via barrier discharges, including intermittent barrier discharges, as described, for example, in the paper "DBD in burst mode: solution for more efficient CO2 conversion" by Oskan et al. (see Plasma Sources Science and Technology, IOP Publishing, 2016, 25(5), p.055005), published at https: / / hal.sorbonne-universite.fr / hal-01367345.

[0008] This technology can also be applied to pulsed discharges, such as those described in the paper "Nanosecond-Pulsed Discharge Plasma Splitting of Carbon Dioxide" by Moon Soo Bak et al. (see IEEE TRANSACTIONS ON PLASMA SCIENCE, Vol. 43, No. 4, April 2015, pp. 1002-1007).

[0009] However, the barrier discharge and pulsed discharge technologies described may result in low conversion process efficiency.

[0010] One problem with non-equilibrium plasmas is that all types of energy losses (including collisions and molecular vibrational excitations) that result in the heating of the gas are irreversible. Unfortunately, these types of losses are usually much larger than the molecular dissociation energy and even larger than the thermal effect (enthalpy) of the reaction. For this reason, the energy efficiency of non-equilibrium plasmas (the proportion of thermal effect to the total energy loss of the process) is usually low, around 10% to 20%.

[0011] An alternative is to heat the gas molecules in a special reaction chamber to a temperature high enough for them to overcome the activation barrier of the reaction. In this case, heating is a useful process, and the process that generates more heat is not a loss.

[0012] However, if the reaction chamber is heated, another problem arises. Specifically, all molecules are heated, and energy is used not only for heating and dissociating the required reagents, but also for heating and dissociating the final reaction product. In this case, significant problems arise from the reverse reaction, which reduces the conversion rate and the energy efficiency of the process.

[0013] One solution to this problem is to remove the reaction products from the high-temperature region after their formation (for example, as soon as possible after formation). This method, which suppresses the reverse reaction, can increase the yield of the desired product and the energy efficiency of the plasma chemical process. This approach can be called quenching of the products of a plasma chemical reaction.

[0014] A technique for performing a plasma chemical reaction is described in U.S. Patent Application Publication No. 2012 / 0090985(A1), published on April 19, 2012. This technique involves a special plasma chemical reactor that uses a gliding arc moving through a gas flow structured as a reverse vortex. The shape of the gliding arc discharge is shown in Figure 1. The plasma arc filament formed after the first dielectric breakdown begins to move and extend due to the gas flow and arc extension, causing an increase in the operating voltage and power of the reactor. Here, (100) is the plasma chemical reactor, 100a is the ground electrode, 100b is the high-voltage electrode, 101 indicates the point of total extinction, 102 indicates the point of the gliding arc generated when maximum energy is transferred, 103 indicates the gliding arc ignition point, 104 indicates the DC power supply, 105 indicates the gas inlet, 106 indicates the reactor, and 107 indicates the plasma filament extension due to the gas flow.

[0015] After applying a voltage to the electrodes, dielectric breakdown occurs in the narrowest gap. Thereafter, the electric arc generated after the dielectric breakdown begins to move through the gas flow from the location where the gap is the narrowest, and as a result, the arc filament elongates. The voltage applied to this arc filament increases because the filament length increases. When this voltage becomes sufficient for a new dielectric breakdown at the location where the gap is the narrowest, a secondary dielectric breakdown occurs, and the process continues repeatedly. This repetitive mode is characteristic of different types of gliding arcs, such as the rotating gliding arc (see "Co-generation of hydrogen and carbon aerosol from coalbed methane surrogate using rotating gliding arc plasma" by Angjian Wu, Xiaodong Li, Jianhua Yan, Jian Yang, Changming Du, Fengsen Zhu, Jinyuan Qian, Applied Energy, Vol. 195, June 1, 2017, pp67 - 79). The voltage and current waveforms of the rotating gliding arc are shown in Figure 2. Note that the rotating gliding arc can also function in the stationary arc length mode.

[0016] The gliding arc plasma reactor can partially solve the problem of quenching the product by passing the product through the plasma channel, but this solution also has some drawbacks resulting from the fact that the velocity of the plasma channel with respect to the gas (slip velocity) is relatively slow, about 1 meter / second. Therefore, at least a portion of the reaction product will undergo secondary treatment, which leads to a significant contribution of the reverse reaction and reduces the conversion rate and energy efficiency of the process.

[0017] On the one hand, there is a need for a system that provides appropriate gas conversion conditions in the high-temperature zone and, at the same time, provides effective quenching of the reaction products. Such a system can significantly enhance the conversion efficiency and energy efficiency. One such system is described in the specification of international application PCT / RU2019 / 000696. One of the objectives of the described system is to increase the efficiency of the process of converting a gas / gas mixture into the desired product by stimulating the forward reaction and minimizing the reverse reaction.

[0018] To achieve this effect, a plasma chemical gas / gas mixture conversion process is disclosed, which includes generating a pulsed discharge in the flow of the gas / gas mixture moving through the reaction chamber at a given speed and generating a plasma channel connecting the electrodes arranged in the reaction chamber.

[0019] The disclosed method reduces the quenching of the reaction products generated in the high-temperature plasma channel. The flow of the gas / gas mixture moving through the reaction chamber at a given speed supplies a new portion of the reagent for conversion and, at the same time, helps to quickly extinguish the just-formed plasma channel, thereby limiting its duration.

[0020] The high-voltage power supply unit generates a pulsed discharge between the electrodes in the form of a high-temperature plasma channel that lasts for about 10 - 500 nanoseconds and has a frequency of about 20 - 300 kHz.

[0021] This solution is very efficient, but further improvement is still needed. For example, the systems and techniques described herein that can address this need further provide various improvements, especially from the perspective of energy efficiency, including the energy efficiency of energy transfer from the power supply to the plasma, the electrode life, and the system scalability. These problems can be addressed, for example, by improving the reactor design and by controlling the mode of controlling the gas flow rate and direction inside the reactor. Summary of the Invention

[0022] Methods and apparatus are disclosed for stabilizing pulsed discharge in a gas flow, improving energy efficiency, including the efficiency of energy transfer from the power source to the plasma, and scalability of plasma chemical reactors. Controlling plasma parameters by controlling the gas flow velocity and direction within the reactor presents several important challenges. In contrast to gliding arc discharges, where the plasma filament is stretched by the gas flow, increasing the voltage and decreasing the current, in nanosecond pulsed discharge systems, the plasma filament exists for only about 100 nanoseconds, and the plasma filament is absent during the time between pulses, so the gas flow has little effect on the plasma filament (Figures 2 and 3). In Figure 2, 201 corresponds to the continuously present plasma filament stretched by the gas flow, 202 corresponds to the moment when the old plasma filament disappears and a new plasma filament is generated, 203 corresponds to the dielectric breakdown point, 204 corresponds to the new arc, and 205 corresponds to the stretching. In Figure 3, 301 corresponds to the time when the plasma is absent. The plasma filament exists only during nanosecond dielectric breakdown times such as 302. The displacement of gas molecules during this time due to the gas flow velocity is negligible. In this case, one solution is to move the high-temperature excited gas trace after the plasma filament has been extinguished, rather than moving the plasma filament itself. The location of the next dielectric breakdown in a nanosecond high-temperature plasma discharge is determined (or at least influenced) by the residual trace of high-temperature and excited gas remaining after the preceding pulse. By moving such a trace, the location of the subsequent dielectric breakdown can be controlled (Figure 4). Figure 4 shows a part of a plasma reaction system. This system includes an anode 401 and a cathode 402. In the system described, the gas may flow along direction 403 as an axial gas flow, resulting in a first dielectric breakdown 404, which may result in a high-temperature and excited gas trace 405. In the system described, the gas may flow along direction 406 as a tangential gas flow.High-temperature and excited gas traces (405, 407, 409) can move under the influence of tangential gas flow (406, 408, 410), and a second dielectric breakdown may occur at a new location (411).

[0023] If the discharge gap differs at different locations, the breakdown voltage can be controlled by moving the preceding pulse trace in the direction of the longer gap (Figure 5). Figure 5 shows a portion of a plasma reaction system, which includes an anode (501) and a cathode (502). In the system described, the gas may flow along direction 503 as an axial gas flow, resulting in a first breakdown 504, which may result in a hot and excited gas trace 505. In the system described, the gas may flow along direction 506 as a tangential gas flow. The hot and excited gas traces (505, 507, 509) can move under the influence of the tangential gas flow (506, 508, 510), and a second breakdown may occur at a new location (511).

[0024] To achieve such control, some disclosed embodiments may include plasma reactor design elements capable of generating a tangential gas velocity in a specific region within the reactor. This tangential gas velocity can be used to induce and control the displacement of a hot and excited gas trace in order to control the location of subsequent dielectric breakdown. Disclosed embodiments may also include plasma channel designs that include devices for inducing and / or controlling gas swirl in a region within the plasma channel.

[0025] The disclosed embodiments may further include a multi-channel design to enhance system scalability and improve electrical efficiency. [Brief explanation of the drawing]

[0026] [Figure 1] This figure shows the gliding arc shape and the plasma filament extension mechanism. [Figure 2]This figure shows the gliding arc voltage and current waveforms. [Figure 3] This figure shows a nanosecond high-temperature plasma pulse discharge in a gas stream. [Figure 4] This figure shows an embodiment in which the dielectric breakdown position of a nanosecond high-temperature plasma pulse discharge is controlled using a tangential gas flow. [Figure 5] This figure shows an embodiment of controlling the dielectric breakdown voltage of a nanosecond high-temperature plasma pulse discharge using a tangential gas flow. [Figure 6] These are photographs of several consecutive pulses of nanosecond high-temperature plasma pulse discharges affected by tangential gas flow. [Figure 7] This figure shows an anode design having an auger-shaped isolator for nanosecond high-temperature plasma pulse discharge with tangential gas flow, according to an exemplary embodiment of the disclosed embodiment. [Figure 8] This figure shows a cathode design having a variable pin length and an auger-shaped isolator for nanosecond high-temperature plasma pulse discharge with tangential gas flow, according to an exemplary embodiment of the disclosed embodiment. [Figure 9] This figure shows a plasma channel having an anode-cathode assembly for nanosecond high-temperature plasma pulse discharge with tangential gas flow, according to an exemplary embodiment of the disclosed embodiment. [Figure 10] This figure shows a plasma reactor having four channels of nanosecond high-temperature plasma pulse discharge with tangential gas flow, according to an exemplary embodiment of the disclosed embodiment. [Figure 11] This figure shows a plasma reactor having 97 channels of nanosecond high-temperature plasma pulse discharge with tangential gas flow, according to an exemplary embodiment of the disclosed embodiment. [Figure 12] This figure shows a plasma reactor having one channel of nanosecond high-temperature plasma pulse discharge according to an exemplary embodiment of the disclosed embodiment. [Figure 13] This is a schematic diagram of a plasma reactor having four channels for nanosecond high-temperature plasma pulse discharge, according to an exemplary embodiment of the disclosed embodiment. [Figure 14]This figure shows the anode, cathode, and total voltage waveforms for an exemplary embodiment disclosed. [Figure 15] The diagram shows the total voltage waveform for a design having an auger-shaped electrode, an additional gas swirl system, and a variable-length cathode pin, according to an exemplary embodiment of the disclosed embodiment, and also the total voltage waveform for a design without these modifications. [Figure 16] This figure shows a plasma chemical reactor according to several embodiments. [Figure 17] This is a diagram illustrating an exemplary electrode configuration. [Figure 18] These are discharge images according to several embodiments. [Figure 19] This figure shows experimental results of CO2 dissociation in an exemplary plasma converter. [Figure 20] This figure shows experimental results of CO2 / CH4 mixture conversion in an exemplary plasma converter. [Figure 21] This figure shows solid sulfur scale deposited on the reactor wall during an exemplary H2S dissociation test. [Figure 22] This figure shows an exemplary plasma reactor and its associated components. [Figure 23] This figure shows an exemplary plasma reactor and its associated components. [Modes for carrying out the invention]

[0027] Further development of plasma chemical reactors based on high-temperature plasma pulse discharge in a gas flow presents several challenges related to energy efficiency, including energy efficiency of energy transfer from power source to plasma, electrode life, and system scalability. Among other potential features, the disclosed embodiments and techniques may provide the ability to jump the plasma filament from one electrode point to another with each pulse, stabilize the breakdown voltage at a sufficiently high level, provide efficient energy transfer from power source to plasma, and / or scale the plasma reactor to any desired capacity. The disclosed embodiments may also provide significantly improved electrode life.

[0028] To stimulate the displacement of a new plasma filament to a new position (relative to the position of a preceding plasma filament), the disclosed embodiments may allow the movement of a hot and excited gas trace after the extinction of the plasma filament. The position and parameters associated with the trace from the preceding plasma filament determine (or influence) the position and breakdown voltage associated with the next plasma filament. For example, if the first breakdown due to a low-temperature gas occurs at a voltage of about 30 kV, the next breakdown may occur at one-third the voltage (about 10 kV) due to the presence of a hot and excited gas trace. Therefore, controlling the hot and excited gas trace from the preceding pulse may be important for controlling the parameters and position of the subsequent plasma filament. Such control may allow the plasma filament to jump from one electrode point to another with each pulse to prevent overheating and melting of a particular electrode point, which can significantly extend electrode life. Furthermore, such control may be important for stabilizing the breakdown voltage, as localized gas overheating can cause fluctuations (e.g., a decrease) in the breakdown voltage associated with the location where such localized gas overheating occurs. An example of such plasma filament behavior is shown in Figure 6.

[0029] One element for controlling the location of a new dielectric breakdown in a nanosecond high-temperature plasma discharge, which is influenced by a residual high-temperature and excited gas trace after a preceding pulse, is to move this trace a certain distance before the next dielectric breakdown occurs. In some cases, this movement may include a parallel movement perpendicular to the preceding filament. To generate such a movement, the disclosed embodiments may generate a perpendicular tangential gas velocity in a particular region of the plasma channel. In some cases, this tangential velocity V tang V tang >f×10 -3 Faster than m / s, where f is the discharge pulse frequency and displacement 10 -3 m is the characteristic distance between adjacent electrode pins. The disclosed embodiments can generate a tangential velocity of about 50 m / s at a typical frequency of 50 kHz. The disclosed embodiments may include a swirling device within the plasma channel to generate this velocity. Optionally, a gas swirling system may be included at the inlet and outlet of the channel. The disclosed embodiments may include any suitable design for generating the described tangential gas velocity. Optionally, electrode isolators having an auger shape may be used as anode and cathode isolators (see Figures 7 and 8).

[0030] Another configuration for enabling and controlling gas swirling within the plasma channel may include a tangential hole (701) in the anode electrode itself, as shown in Figure 7. Such a configuration can generate a desirable tangential velocity at locations that may be important when controlling the movement of the plasma filament position between pulses (such as near the electrode end).

[0031] Some disclosed embodiments may also include electrode configurations that enable voltage control (e.g., maintaining a specific minimum breakdown voltage level, avoiding significant drops in breakdown voltage) and stabilization. In some cases, such configurations may include variable-length electrode pins. An exemplary cathode including variable-length electrode pins (801) is shown in Figure 8. An example of a cathode including variable-length pins (901) and an anode including tangential holes (902) assembled on an auger-shaped isolator in a cylindrical plasma channel (900) is shown in Figure 9. Such configurations can generate a stable voltage, among other operating characteristics that are advantageous for stimulating plasma chemical reactions.

[0032] In particular, features of the disclosed embodiments, including multi-channel reactors, may enable scaling up to any desired capacity. Such multi-channel reactors may include any of the features and operating characteristics described herein for one or more of the channels within the multi-channel reactor. In some cases, many similar parallel channels with common flow inlets and outlets may be employed to provide any desired reactor capacity. An example of a four-channel reactor is shown in Figure 10. Each channel has a gas injection system with tangential holes configured to facilitate the equalization of the gas flow through each channel.

[0033] The number of channels in a multi-channel reactor can be increased to provide reactor modules with any suitable / desired capacity. Further scaling can be achieved by increasing the number of modules used to form the reactor. One exemplary configuration of a plasma reactor module with 97 plasma channels is shown in Figure 11.

[0034] For example, stabilization of the dielectric breakdown voltage supplied during the operation of the disclosed plasma chemical reactor by a gas swirling element associated with the plasma channel (e.g., directly installed) can have several advantages. In some cases, such stabilization can significantly increase energy efficiency, including the energy efficiency of energy transfer from the power source to the plasma. In some cases, in addition to the other techniques described herein, the dielectric breakdown voltage can be stabilized at least partially by using a charge matching circuit provided between a high-voltage transformer and electrodes. Such a circuit is schematically represented in Figure 12. In Figure 12, 1201 represents the driver, 1202 represents the variac (110V, 20A), 1203 represents the driver signal, 1204 represents the diode bridge (4X60EPF12), 1205 represents the capacitor (6x820μF, 200V), 1206 is +500V, 1207 represents the 3-turn primary winding, 1208 represents the power module, and 1209 is 220 turns The diagram shows the secondary winding, 1210 shows an inductor (5.5 mHn), 1211 shows a capacitor (550 pF), 1212 shows capacitors (500 pF each), 1213 shows a plasma channel, 12014 shows a high-voltage rectifier / current stabilizer, 1215 shows an IGBT module (CM200DU-24NFH), and 1216 shows an IGBT module (CM200DU-24NFH). As illustrated, this circuit may include an inductor and capacitors loaded on two half-wave rectifiers connected in series, each containing a high-voltage diode and a capacitor. In some cases, one rectifier may contain a positively charged anode and the other a negatively charged cathode. The charging of such a matched circuit may generate voltage oscillations on the flat top of the rectangular pulse of voltage generated by the high-voltage transformer. Such oscillations can gradually generate quasi-continuous charging at characteristic frequencies higher than the frequency of the voltage signal in the high-voltage transformer (e.g., more than 10 times higher). This quasi-continuous charging can reduce or prevent charging energy loss (Figure 14). In Figure 14, 1400 is a voltage-time plot, 1401 corresponds to the total voltage, 1402 corresponds to the anode voltage, and 1403 corresponds to the cathode voltage.In some cases, it may be desirable to achieve a discharge breakdown frequency at least twice the operating frequency of the transformer. As shown in Figure 14, the transformer's operating frequency is approximately 25 kHz, but the discharge breakdown stabilizes at approximately 50 kHz. The quasi-continuous charging process described can reduce or minimize charging energy loss. In the schematic diagram shown in Figure 14, a high-voltage transformer powered by an IGBT bridge was used. However, other examples may include flyback and / or push-pull semi-bridge configurations. Furthermore, other transistor types can also be used.

[0035] The described matching circuit between the high-voltage transformer and the electrodes can also be used to divide power from one high-voltage transformer and inverter into a desired number of channels. An example of such a division configuration (e.g., division into four channels) is shown in Figure 15. In Figure 15, 1501 shows a plot of voltage against time corresponding to a design without modifications to the gas swirling and boosting system, and 1502 shows a plot of voltage against time corresponding to a designed auger-shaped electrode, an additional gas swirling system, and a variable-length cathode pin. The example shown in Figure 15 involves a division into four channels, but other numbers of channels may be provided similarly. The stabilization and control of the dielectric breakdown voltage of the described plasma channels, associated with the described configuration for facilitating gas swirling in the plasma channels, can significantly improve the operational efficiency (among other advantages) of simultaneous operation of several different plasma channels powered by a single high-voltage transformer and inverter. Furthermore, the configurations and techniques described can facilitate dielectric breakdown voltage stabilization, reduce or minimize charge energy loss, enable system capacity scalability to any desired number of plasma channels, and improve the efficiency of the plasma chemical reactor.

[0036] Embodiments of this disclosure may also include one or more features or be used in one or more processes, as described in the following sections.

[0037] Plasma can provide powerful instruments for carrying out chemical reactions with high activation energies, such as synthesis gas production, CO2 dissociation, and H2S dissociation. However, conventional plasma technologies, such as electric arcs or microwave discharges, can have some drawbacks for plasma chemistry applications. For example, these types of systems can have challenges in maintaining conditions for direct chemical reactions (e.g., chemical reactions that transfer an initial reagent to a substance) while avoiding reverse chemical reactions. In plasma chemistry, this is called quenching and involves the rapid removal of reaction products from the high-temperature reaction zone.

[0038] The disclosed approach may provide an efficient solution for quenching. This type of discharge may involve a series of electrical breakdowns of the gas, which can be observed, for example, as a fine needle appearing and disappearing each time in a new location. In this way, the initial reagent can be processed to generate the desired product and substantially avoid reverse chemical reactions by rapidly eliminating the plasma channel. The frequency of such breakdowns is below 100 kHz, which is sufficient for efficient processing of high-flow gases.

[0039] Figure 16 shows an exemplary plasma chemical reactor based on the principle of generation and extinction of a high-temperature plasma channel between the anode and cathode at high frequency. Figure 16 shows a gas injection module (1), anode (2), anode high-voltage connector (3), discharge box (4), cathode (5), cathode high-voltage connector (6), gas exhaust module (7), and a high-voltage power supply with special electrical properties.

[0040] The cathode and / or anode may have a disk shape as shown in Figure 17(9). In some cases, the anode and cathode may have a disk shape with sharp edges or a disk shape with several needles.

[0041] A plasma chemical reactor based on the principle of generating and extinguishing a high-temperature plasma channel between a high-frequency anode and cathode may include a gas injection module (Figure 16(1)), an anode (Figure 16(2)), an anode high-voltage connector (Figure 16(3)), a discharge box (Figure 16(4)), a cathode (Figure 16(5)), a cathode high-voltage connector (Figure 16(6)), a gas exhaust module (Figure 16(7)), and a high-voltage power supply with an output capacitor C having a capacitance (nF) > average current (A) × 100 or greater.

[0042] In addition, the exemplary system disclosed may recirculate the gas by an additional gas pump to increase the gas velocity through the discharge zone, independently of the supply gas flow.

[0043] The disclosed system may include an additional high-voltage capacitor connected in parallel to the power supply output connector in Figure 16(8).

[0044] The exemplary system disclosed can direct the flow of working gas from the anode to the cathode (or vice versa).

[0045] Figure 18 shows a discharge image according to an exemplary embodiment disclosed.

[0046] In the exemplary systems disclosed, the shape and material of either or both of the cathode and anode may include one or more of the following in various combinations: ·disk, • Discs with sharp edges, • A disc with several needles, and • Cone with a through hole

[0047] In some embodiments, bronze BRX, tungsten, titanium, and molybdenum can be used as electrode materials.

[0048] The exemplary system setups disclosed may include any combination of the following: - A step of adjusting the flow rate of the working gas passing through the spark discharger. • A step of adjusting the operating gas pressure in the discharge device. • A step of changing the distance between electrodes, • A step of changing the discharge voltage between electrodes. Exemplary features of the disclosed plasma reactor include high electrical efficiency, improved energy efficiency of plasma chemical processes (minimal energy costs), a robust and reliable electrode design that can extend lifespan and reduce the need for component replacement, and an extremely compact plasma reactor design.

[0049] Exemplary uses of the disclosed system include CO2 dissociation. Figure 19 shows CO2 dissociation in an exemplary plasma converter. Exemplary CO2 dissociation processes may be used for reducing CO2 in exhaust gases (e.g., CO2 emission reduction), converting CO2 to liquid fuels (e.g., CO2 emission reduction), oxygen production from CO2 in space applications, and hydrogen production (replacing electrolysis processes).

[0050] Methods for producing synthesis gas (e.g., from a CH4 / CO2 mixture) are also disclosed. Exemplary processes may be used for CO2 / CH4 conversion for hydrogen production and / or CO2 conversion to liquid fuels using electrical energy and methane. Synthesis gas may be produced from a CH4 / CO2 mixture.

[0051] Figure 20 shows experimental results of the conversion of an exemplary CO2 / CH4 mixture to CO and H2 in a plasma converter, and the dependence of energy costs on flow rate for different mixture compositions. In Figure 20, 2001 corresponds to a CH4 / CO2 ratio of 1.46, 2002 corresponds to a CH4 / CO2 ratio of 0.45, 2003 corresponds to a CH4 / CO2 ratio of 0.95, and 2004 corresponds to a CH4 / CO2 ratio of 0.67.

[0052] Methods for hydrogen sulfide (H2S) dissociation are also disclosed. H2S conversion is one of the important processes in oil and gas refining plants. Conventional techniques based on the Kraus process have significant drawbacks (the main product generated for the process, namely hydrogen, is converted to H2O and consequently lost). On the other hand, exemplary plasma processes for H2S dissociation into hydrogen and sulfur may be more efficient when the energy cost of dissociation is about 1 eV / H2S molecule. In some embodiments, the plasma process converts H2S into two useful products, namely hydrogen (which can be recovered) and solid sulfur. After hydrogen sulfide (H2S) dissociation, the solid sulfur can be melted off from the reactor wall. Sulfur can be removed from the gas flow by electrostatic precipitation. Figure 21 shows solid sulfur scaled onto the reactor wall during an H2S dissociation test.

[0053] The technology of plasma conversion of gas mixtures can provide an effective means for many potential applications, including CO2 utilization (such as CO2 emission reduction) and hydrogen production. The illustrated system disclosed can offer the following advantages: • Energy efficiency • Operating costs • Simple, reliable, and compact design

[0054] The exemplary systems disclosed may also be used, for example, to convert ethane to ethylene or propane to propylene according to C2H6 → C2H4 + H2 and C3H8 → C3H6 + H2.

[0055] Furthermore, the exemplary systems disclosed may be used to convert butane and / or isobutene to butylene and isobutylene. For example, C4H 10 → C4H8 + H2

[0056] Furthermore, the disclosed system may be used to synthesize acetylene, for example, CH4 (generally C x H 2x+2 ) → C2H2 + 2H2.

[0057] In some embodiments, the disclosed system may be used to produce hydrogen gas (for example, for use when refueling a hydrogen fuel cell).

[0058] The plasma reactors disclosed herein may have a variety of configurations. In some embodiments, the plasma reactor may be associated with, or include, various components for providing one or more aspects of the functionality of the plasma reactor. Such components may include, but are not limited to, one or more power supply units, power supply circuits, gas flow regulators, sensors, etc. Such components may also include one or more processing units (e.g., microcontrollers or other types of logic devices) for automatically controlling or performing one or more functions of the plasma reactor. Such processing units may control plasma filament generation and / or plasma filament timing by automatic control of various power supply components (e.g., based on feedback received by the control unit), circuit elements, gas flow regulators, etc. While the disclosed plasma reactors may be automatically controlled using one or more logic-based controllers, in some embodiments, the disclosed plasma reactors may be implemented using analog electronic components. One such embodiment for generating and extinguishing the plasma filaments described is shown in Figure 22. In Figure 22, 2201 represents a high-voltage transformer, 2202 a high-voltage diode bridge, 2203 a rectifier capacitor, 2204 a high-voltage resistor, 2205 a pulse output capacitor, and 2206 a plasma chemical reactor.

[0059] In this example in Figure 22, a high-voltage transformer and diode bridge can generate a high voltage across the rectifier capacitor. A high-voltage resistor can control or provide a desired level of current for charging the pulse output capacitor. After charging to a voltage sufficient to cause dielectric breakdown of the electrodes of the plasma chemical reactor, the pulse output capacitor can discharge through the plasma channels within the plasma chemical reactor to form a plasma filament. When the polarity changes, the plasma filament can be extinguished by the gas flow. The process of plasma filament generation and subsequent extinguishing can be repeated continuously for any desired period of time.

[0060] Various voltages and resistances can be used in the plasma reactor and associated electronic components described above. In one example, the experimental setup included the use of a 60kV output voltage applied to a rectifier capacitor. The high-voltage resistor was 100kΩ. The pulse output capacitor was 350pF. Using these components, the resulting plasma filament generation / extinction cycle had a frequency of approximately 60kHz. The effective inductance of the circuit for discharging the pulse output capacitor through the plasma chemical reactor was 0.5μHn. The current pulse duration and plasma filament lifetime were approximately 150 nanoseconds.

[0061] Another example of a plasma reactor and related components is shown in Figure 23. In Figure 23, 2301 is a high-voltage high-frequency transformer, 2302 is a voltage amplifier, 2303 is a high-voltage diode, 2304 is a high-voltage capacitor, 2305 is a pulse output capacitor, and 2306 is a plasma chemical reactor.

[0062] A high-voltage transformer and voltage amplifier scheme based on diodes and capacitors can provide the desired current charge to a pulse output capacitor. After charging to a voltage sufficient for dielectric breakdown, the plasma chemical reactor pulse output capacitor can discharge through the plasma channel to form a plasma filament. At the moment of polarity change (or at some point after the signal polarity change), the plasma filament can be extinguished by the gas flow. The process can be repeated continuously.

[0063] In one example, the experimental setup included a 100pF multiplier capacitor. A high-frequency high-voltage transformer was operated at frequencies of 30kHz and 60Hz, respectively. The pulse output capacitor was 300pF. As a result, the plasma pulse frequencies were 30kHz and 60kHz, respectively. The effective inductances of the discharge circuit of the pulse output capacitor through the plasma chemical reactor were 0.5μHn, 0.125μHn, and 0.03μHn, respectively. The current pulse duration and plasma filament lifetime were 180 nanoseconds, 80 nanoseconds, and 30 nanoseconds, respectively.

[0064] Some further exemplary embodiments include: An exemplary reactor with an off-time longer than the on-time.

[0065] In some embodiments, the plasma reactor may repeatedly generate and extinguish plasma filaments such that the dwell time (off time) when no plasma filaments are present is significantly longer than the plasma discharge interval (on time) when plasma filaments are present. In some embodiments, the longer off time may be important to allow subsequent filaments to follow a different path than their preceding filaments (leading to improved efficiency).

[0066] In some embodiments, a plasma reactor is provided for converting at least one chemical species into one or more reaction products, comprising: an electrode pair; a gas inlet configured to deliver a gas to the location of the electrode pair; and a power supply configured to generate a time-varying voltage between the electrode pair, wherein the time-varying voltage is configured to cause the generation of plasma filaments between the electrode pair during each of a plurality of continuous discharge intervals such that each of a plurality of continuous discharge intervals is temporally separated from another discharge interval among the plurality of discharge intervals by a dwell interval in which no plasma filaments are present between the electrode pair, and the average dwell interval time is at least 10 times the average discharge interval time.

[0067] In some embodiments, a plasma reactor is provided for converting at least one chemical species into one or more reaction products, comprising: an electrode pair; a gas inlet configured to deliver a gas to the location of the electrode pair; a power supply configured to generate a time-varying voltage between the electrode pair; and at least one processor configured to control the power supply to generate plasma filaments between the electrode pair during each of a plurality of consecutive discharge intervals such that each of a plurality of discharge intervals is temporally separated from another discharge interval among the plurality of discharge intervals by a dwell interval in which no plasma filaments are present between the electrode pair, wherein the average dwell interval time is at least 10 times the average discharge interval time.

[0068] In some embodiments, at least one processor is configured to control the energy supply to the electrode pair in order to ignite and extinguish the plasma filament at least 50,000 times per second for at least 10 minutes.

[0069] In some embodiments, the duration of each of the multiple discharge intervals is substantially the same.

[0070] In some embodiments, the ratio of the average duration of the dwell interval to the average duration of the discharge interval is at least 50.

[0071] In some embodiments, the ratio of the average duration of the dwell interval to the average duration of the discharge interval is at least 100.

[0072] In some embodiments, the duration of at least one of the multiple discharge intervals is different from the duration of another of the multiple discharge intervals.

[0073] In some embodiments, at least one processor is configured to control the power supply so that the average duration of a plurality of discharge intervals is about 50 nanoseconds to 200 nanoseconds, and the average duration of a dwell interval is about 500 nanoseconds to 15,000 nanoseconds.

[0074] In some embodiments, the distance between a pair of electrodes is approximately 2 cm to 10 cm.

[0075] In some embodiments, the distance between a pair of electrodes is approximately 5 cm to 7 cm.

[0076] In some embodiments, the average diameter of the plasma filaments generated between each discharge interval is approximately 50 to 1000 micrometers.

[0077] In some embodiments, at least one electrode of an electrode pair includes one or more needle structures extending from the surface of its distal end.

[0078] In some embodiments, at least one of the pair of electrodes contains hafnium. Exemplary plasma filament deactivation for reducing reverse reaction

[0079] In some embodiments, after the plasma filament has undergone a chemical reaction, the plasma filament is extinguished for a sufficient period of time to prevent a reverse reaction from occurring.

[0080] In some embodiments, including a plasma generator for accelerating a chemical reaction, the plasma generator may include a reaction chamber, an anode and a cathode within the reaction chamber, connected to a circuit for delivering energy between the anode and cathode, a gas inlet for supplying at least one reaction gas to the regions of the anode and cathode, a valve for controlling the flow of reaction gas through the gas inlet, configured to adjust the amount of reaction gas flowing into the regions of the anode and cathode, and a power supply configured to deliver energy to the circuit and to limit the reverse reaction following the chemical reaction by adjusting the energy delivery in the cycle such that a first average cycle time when no energy is delivered to the circuit is sufficiently longer than a second average cycle time when energy is delivered to the circuit.

[0081] In some embodiments including a plasma generator for accelerating a chemical reaction, the plasma generator may include a reaction chamber; an anode and a cathode within the reaction chamber, connected to a circuit for delivering energy between the anode and cathode; a gas inlet for supplying at least one reaction gas to the regions of the anode and cathode; a valve for controlling the flow of reaction gas through the gas inlet; a power supply configured to deliver energy to the circuit; and at least one processor configured to control the valve to adjust the amount of reaction gas flowing into the regions of the anode and cathode, and to adjust the energy delivery in cycles from the power supply to the circuit such that a first average cycle time when no energy is delivered to the circuit is sufficiently longer than a second average cycle time when energy is delivered to the circuit, thereby limiting the reverse reaction following the chemical reaction.

[0082] In some embodiments, the first average cycle time is at least 50 times longer than the second average cycle time.

[0083] In some embodiments, the second average cycle time is less than approximately 200 nanoseconds. Exemplary high-frequency plasma discharge with intervening dwell time

[0084] In some embodiments, the disclosed plasma reactor may operate at a high frequency (e.g., above 50 kHz or 100 kHz) but interleave dwell times between generated plasma filament events to repeatedly generate and extinguish plasma filaments. In some embodiments, high-frequency operation and interleaved dwell times may be key factors in improving performance compared to other systems that maintain a continuous plasma discharge (e.g., microwave plasma systems). For example, high frequency and relatively long dwell times may result in rapid quenching of gaseous reaction products, which can lead to improved efficiency.

[0085] In some embodiments, a plasma reactor is provided for converting at least one chemical species into one or more reaction products, comprising: an electrode pair; a gas inlet configured to deliver a gas to the location of the electrode pair; and a power supply configured to generate a time-varying voltage between the electrode pair to generate a series of periodic plasma discharge events between the electrode pair that are temporally separated from each other by a dwell time during which no plasma discharge occurs between the electrode pair, and to generate periodic plasma discharge events at a frequency of at least 50 kHz.

[0086] In some embodiments, a plasma reactor is provided for converting at least one chemical species into one or more reaction products, comprising: an electrode pair; a gas inlet configured to deliver a gas to the location of the electrode pair; a power supply; and at least one processor configured to generate a time-varying voltage between the electrode pair to generate a series of periodic plasma discharge events between the electrode pair that are temporally separated from each other by a dwell time during which no plasma discharge occurs between the electrode pair; and to generate periodic plasma discharge events at a frequency of at least 50 kHz.

[0087] In some embodiments, at least one processor is configured to generate periodic plasma discharge events at a frequency of at least 100 kHz.

[0088] In some embodiments, at least one processor is configured to make the dwell time duration at least 10 times the average duration of each plasma discharge event.

[0089] In some embodiments, at least one processor is configured to make the dwell time duration at least 100 times the average duration of each plasma discharge event.

[0090] In some embodiments, at least one processor is configured to have an average duration of about 50 nanoseconds to about 150 nanoseconds for each plasma discharge event, and a dwell time duration of at least 1500 nanoseconds.

[0091] In some embodiments, the average duration of each plasma discharge event is approximately 50 nanoseconds to approximately 150 nanoseconds, and the dwell time duration is at least 10,000 nanoseconds.

[0092] In some embodiments, the distance between a pair of electrodes is approximately 2 cm to 10 cm.

[0093] In some embodiments, the distance between a pair of electrodes is approximately 5 cm to 7 cm.

[0094] In some embodiments, at least one processor is configured such that each plasma discharge event generates a plasma filament between electrode pairs, with an average radius of the plasma filament being approximately 50 to 1000 micrometers. Exemplary control of filament instability to generate intervening dwell time

[0095] In some embodiments, periodic instability may be introduced in the disclosed plasma reactor to extinguish plasma filaments. The instability is generated by a change in the polarity of a voltage signal applied to an electrode pair, which makes it possible to extinguish the filaments, for example, by a gas flowing through the reaction chamber.

[0096] Some embodiments provide a plasma reactor for converting at least one chemical species into one or more reaction products, comprising: a reaction chamber; an electrode pair within the reaction chamber; a power supply configured to vary at least one of voltage and current between the electrode pair between positive and negative polarity to initiate plasma ignition during the positive polarity period and to introduce instability in the generated plasma filament during each negative polarity period; and at least one gas conduit configured to direct gas to a region of the generated plasma filament such that the generated plasma filament is maintained during each positive polarity period of the applied voltage and extinguished during each negative polarity period and after the occurrence of instability in the generated plasma filament.

[0097] Some embodiments provide a plasma reactor for converting at least one chemical species into one or more reaction products, comprising: a reaction chamber; an electrode pair within the reaction chamber; a power supply; at least one processor configured to vary at least one of voltage and current between the electrode pair between positive and negative polarity to initiate plasma ignition during the positive polarity period and to introduce instability in the generated plasma filament during each negative polarity period; and at least one gas conduit configured to direct gas to a region of the generated plasma filament such that the generated plasma filament is maintained during each positive polarity period of the applied voltage and extinguished during each negative polarity period and after the occurrence of instability in the generated plasma filament.

[0098] In some embodiments, at least one processor is configured to initiate instability of the generated plasma filaments when the voltage between electrode pairs changes from positive to negative polarity.

[0099] In some embodiments, the fluctuating voltage is periodic, and a single cycle of the fluctuating voltage includes a positive polarity portion and a negative polarity portion.

[0100] In some embodiments, the generated plasma filament is maintained for the duration of the discharge, at least partially within the positive polarity portion, and during the dwell time, which includes the negative polarity portion and part of the positive polarity portion, the plasma filament is not present between the electrode pair, and the dwell time is longer than the discharge time.

[0101] In some embodiments, the generated plasma filament is maintained for a discharge time shorter than the dwell time during which the plasma filament is not present between the electrode pair.

[0102] In some embodiments, the dwell time is at least 10 times the discharge time.

[0103] In some embodiments, the dwell time is at least 100 times the discharge time.

[0104] In some embodiments, the fluctuating voltage has a sawtooth waveform.

[0105] In some embodiments, the gas directed towards the region of the generated plasma filament has a flow rate of 0.1 to 50 liters / minute. Exemplary gas flow rates for controlling filament ignition and extinction

[0106] In some disclosed embodiments, the gas flow rate may be important for enabling repeated plasma filament ignition and extinction. In some embodiments, if the gas flow rate is too high, the filament will not ignite, and if the gas flow rate is too low, the filament will not extinguish. Thus, the gas flow can be controlled.

[0107] In some embodiments, a plasma reactor is provided for converting at least one chemical species into one or more reaction products, comprising: a reaction chamber; an electrode pair; a power supply configured to generate a time-varying voltage between the electrode pair that periodically varies between a maximum and a minimum value; and at least one gas conduit controlled to direct a gas into the region of the electrode pair at a flow rate selected to enable the generation of plasma filaments and to cause the extinguishing of the generated plasma filaments between consecutive maximum values ​​of the time-varying voltage.

[0108] In some embodiments, a plasma reactor is provided for converting at least one chemical species into one or more reaction products, comprising: a reaction chamber; an electrode pair; at least one processor configured to control a power supply that generates a time-varying voltage between the electrode pair that periodically varies between a maximum and a minimum value; and at least one gas conduit controlled to direct a gas into the region of the electrode pair at a flow rate selected to enable the generation of plasma filaments and to cause the extinguishing of the generated plasma filaments between consecutive maximum values ​​of the time-varying voltage.

[0109] In some embodiments, the reactor further comprises a gas valve associated with a gas conduit, and at least one processor is configured to control the gas valve to deliver gas at a flow rate that causes repeated filament generation and extinguishing.

[0110] In some embodiments, the reactor further includes sensors that detect at least one of filament generation and extinguishing and provide an output to a processor to adjust a valve.

[0111] In some embodiments, the reactor further includes sensors that detect the gas flow rate and provide an output to a processor to adjust the valve.

[0112] In some embodiments, the gas directed towards the region of the generated plasma filament has a flow rate of 0.1 to 50 liters / minute.

[0113] In some embodiments, the time-varying voltage has a frequency of at least 50 kHz.

[0114] In some embodiments, plasma filament generation occurs at a rate of at least 50 kHz.

[0115] In some embodiments, the time-varying voltage has a frequency of at least 100 kHz.

[0116] In some embodiments, plasma filament generation occurs at a rate of at least 100 kHz. Exemplary rotating gas flow for improving efficiency

[0117] In some embodiments, the gas flow may have a rotational component in addition to the primary axial component of motion. This rotational component can be important for the system's efficiency, potentially resulting in up to five times (or more) the efficiency of a tubular reactor system that relies solely on laminar flow.

[0118] In some embodiments, a plasma reactor is provided for converting at least one chemical species into one or more reaction products, comprising: a reaction chamber; an electrode pair within the reaction chamber; a power supply electrically connected to the electrode pair and configured to generate periodic plasma discharge events between the electrode pair in response to a time-varying voltage applied between the electrode pair, which are temporally separated by a dwell time period during which no plasma discharge occurs; and at least one gas conduit configured to direct a gas flow into the region of the electrode pair such that the gas flow includes both longitudinal and rotational components of motion with respect to an axis passing through the electrode pair.

[0119] In some embodiments, a plasma reactor is provided for converting at least one chemical species into one or more reaction products, comprising: a reaction chamber; an electrode pair within the reaction chamber; a power supply electrically connected to the electrode pair; at least one processor configured to control the power supply to generate periodic plasma discharge events between the electrode pair in response to a time-varying voltage applied to the electrode pair, which are temporally separated by a dwell time period during which no plasma discharge occurs; and at least one gas conduit configured to direct a gas flow into the region of the electrode pair such that the gas flow includes both longitudinal and rotational components of motion with respect to an axis passing through the electrode pair.

[0120] In some embodiments, the reactor further comprises at least one valve associated with a gas conduit for adjusting the gas flow rate.

[0121] In some embodiments, at least one processor is configured to control at least one valve to produce a gas flow having a longitudinal velocity of 0.1 liters / min to 50 liters / min.

[0122] In some embodiments, the rotational component of the motion is sufficient to displace molecules in the gas flow by a distance greater than or equal to the average diameter of the plasma filaments generated during a periodic plasma discharge event.

[0123] In some embodiments, the rotational component of the gas flow motion causes the plasma filaments generated during a periodic plasma discharge event to travel along a spline-like path.

[0124] In some embodiments, the dwell time is at least 10 times the discharge time associated with the periodic plasma discharge event.

[0125] In some embodiments, the dwell time is at least 100 times the discharge time associated with the periodic plasma discharge event.

[0126] In some embodiments, periodic plasma discharge events occur at a frequency of at least 50 kHz.

[0127] In some embodiments, periodic plasma discharge events occur at a frequency of at least 100 kHz. Exemplary subsequent filament following a new path

[0128] In some embodiments, by making the off-time longer than the on-time, each new plasma filament can follow a different path than the preceding filament. This feature helps ensure that each generated filament is exposed to more unreacted reactants than quenched reaction products, which can increase reactor efficiency.

[0129] Some embodiments provide a plasma reactor for converting at least one chemical species into one or more reaction products, comprising a reaction chamber, an electrode pair within the reaction chamber, and a power supply configured to generate a time-varying voltage between the electrode pair, the time-varying voltage being configured to generate plasma filaments between the electrode pair during each of a plurality of discharge intervals such that each of a plurality of discharge intervals is temporally separated from another of the plurality of discharge intervals by a dwell interval in which no plasma filaments are present between the electrode pair, and the duration of the dwell interval is sufficient to cause subsequent plasma filaments generated during a subsequent discharge interval to follow a different path than that of preceding plasma filaments generated during a preceding discharge interval.

[0130] Some embodiments provide a plasma reactor for converting at least one chemical species into one or more reaction products, comprising: a reaction chamber; an electrode pair within the reaction chamber; a power supply; and at least one processor configured to control the power supply to generate a time-varying voltage between the electrode pair, which is configured to generate plasma filaments between the electrode pair between each of a plurality of discharge intervals; to control the power supply so that each of the plurality of discharge intervals is temporally separated from another discharge interval among the plurality of discharge intervals by a dwell interval in which no plasma filaments are present between the electrode pair; and to control the power supply so that the duration of the dwell interval is sufficient to cause subsequent plasma filaments generated during a subsequent discharge interval to follow a different path than that of preceding plasma filaments generated during a preceding discharge interval.

[0131] In some embodiments, the average dwell interval is at least 10 times the average discharge interval.

[0132] In some embodiments, the average dwell interval is at least 50 times the average discharge interval.

[0133] In some embodiments, the average dwell interval is at least 100 times the average discharge interval.

[0134] In some embodiments, the duration of the average discharge interval is 50 nanoseconds to 150 nanoseconds, and the duration of the average dwell interval is at least 2500 nanoseconds.

[0135] In some embodiments, the duration of the average dwell interval is at least 10,000 nanoseconds.

[0136] In some embodiments, the duration of the average dwell interval is at least 15,000 nanoseconds.

[0137] In some embodiments, the discharge interval occurs at a frequency of at least 50 kHz.

[0138] In some embodiments, the discharge interval occurs at a frequency of at least 100 kHz. Exemplary gas flow monitoring and improvement measures

[0139] In some embodiments, the gas flow rate may be a critical parameter for several aspects of the disclosed reactor. Therefore, a control system for monitoring the gas flow rate and taking one or more corrective actions if the flow rate is outside a predetermined range may be critical to the operation and performance of the reactor.

[0140] In some embodiments, a control system for a plasma reactor is configured to periodically ignite and extinguish plasma filaments in conjunction with a gas flow through the plasma reactor, and the control system comprises at least one processor configured to receive an instruction for the gas flow rate through the plasma reactor, determine whether the received instruction for the gas flow rate indicates a current gas flow rate that is below a threshold sufficient to allow the periodic extinguishing of the plasma filaments, and if it is determined that the current gas flow rate is below the threshold, initiate at least one corrective action.

[0141] In some embodiments, the corrective action includes issuing a warning.

[0142] In some embodiments, the warning includes at least one of an audible warning or a visual warning.

[0143] In some embodiments, the improvement measures include increasing the gas flow rate in the plasma reactor.

[0144] In some embodiments, the improvement measures include increasing the operating speed of at least one pump.

[0145] In some embodiments, the corrective measures include shutting down the plasma reactor. Example: Parallel path reactor

[0146] In some embodiments, a plasma reactor having multiple parallel gas channels, each containing at least one pair of electrodes, can offer significantly higher stability than a single-channel reactor. Such a reactor may be less susceptible to adverse effects caused by fluctuations in gas flow, for example.

[0147] In some embodiments, a plasma reactor is provided for converting at least one chemical species into one or more reaction products, comprising: a reactor having a reactor flow path; a first gas flow chamber in the flow path defining a first sub-flow path in the reactor flow path; a first electrode pair disposed in the first gas flow chamber; at least one second gas flow chamber in the reactor flow path defining a second sub-flow path in the reactor flow path, wherein the first and second sub-flow paths are substantially parallel; at least one second electrode pair disposed in the at least one second gas flow chamber; and at least one power supply configured to generate at least one time-varying voltage on each of the first and second electrode pairs to enable the continuous generation and extinguishing of plasma filaments in each of the first and at least second gas flow chambers.

[0148] In some embodiments, a plasma reactor is provided for converting at least one chemical species into one or more reaction products, comprising: a reactor having a reactor flow path; a first gas flow chamber in the flow path defining a first subflow path in the reactor flow path; a first electrode pair disposed in the first gas flow chamber; at least one second gas flow chamber in the reactor flow path defining a second subflow path in the reactor flow path, wherein the first and second subflow paths are substantially parallel; at least one second electrode pair disposed in at least one second gas flow chamber; at least one power supply; and at least one processor configured to generate at least one time-varying voltage on each of the first and second electrode pairs to enable the continuous generation and extinction of plasma filaments in each of the first and second gas flow chambers.

[0149] In some embodiments, at least one of the first electrode pair or the second electrode pair is oriented with respect to each gas flow chamber such that the electric field axis between the first electrode pair or the second electrode pair is aligned parallel to the flow path of each gas flow chamber.

[0150] In some embodiments, at least one of the first electrode pair or the second electrode pair is oriented with respect to each gas flow chamber such that the electric field axis between the first electrode pair or the second electrode pair is positioned at a non-zero angle with respect to the flow path of each gas flow chamber.

[0151] In some embodiments, at least one of the first electrode pair or the second electrode pair is oriented with respect to each gas flow chamber such that the electric field axis between the first electrode pair or the second electrode pair is positioned at an angle of about 90 degrees with respect to the flow path of each gas flow chamber.

[0152] In some embodiments, the plasma reactor includes at least three gas flow chambers whose longitudinal axes are substantially parallel and located at the vertices of a triangle.

[0153] In some embodiments, the plasma reactor includes a plurality of gas flow chambers arranged in a hexagonal close-packed configuration, with their longitudinal axes substantially parallel to one another. Exemplary CO 2 dissociation device

[0154] In some embodiments, potentially important use cases of the disclosed plasma reactor may include the dissociation of carbon dioxide, well-known industrial pollutants, and greenhouse gases. Not only can the disclosed reactor be used to reduce carbon dioxide emissions from various sources, but the system can also provide efficiencies of less than 4 eV / mol, which is not possible with current technology.

[0155] In some embodiments, a plasma reactor is provided for dissociating carbon dioxide into carbon monoxide and oxygen, comprising: a carbon dioxide reaction chamber defining a gas flow path; an inlet within the reaction chamber configured to supply carbon dioxide to the gas flow path; an electrode pair positioned within the gas flow path; a power supply configured to generate a voltage between the electrode pair to enable the generation of plasma filaments between the electrode pair, and also configured to control the voltage supplied between the electrode pair over time to repeatedly form and extinguish plasma filaments between the electrodes, so that when the plasma filaments are present between the electrode pair, the plasma filaments interact with carbon dioxide and cause the dissociation of carbon dioxide into carbon monoxide and oxygen; and at least one outlet within the reaction chamber configured to discharge carbon monoxide and oxygen from the reaction chamber.

[0156] In some embodiments, a plasma reactor is provided for dissociating carbon dioxide into carbon monoxide and oxygen, comprising: a carbon dioxide reaction chamber defining a gas flow path; an inlet within the reaction chamber configured to supply carbon dioxide to the gas flow path; an electrode pair positioned within the gas flow path; a power supply; at least one processor configured to generate a voltage between the electrode pair to enable the generation of plasma filaments between the electrode pair, and to control the voltage supplied between the electrode pair over time to repeatedly form and extinguish plasma filaments between the electrodes, so that when the plasma filaments are present between the electrode pair, the plasma filaments interact with carbon dioxide and cause the dissociation of carbon dioxide into carbon monoxide and oxygen; and at least one outlet within the reaction chamber configured to discharge carbon monoxide and oxygen from the reaction chamber.

[0157] In some embodiments, at least one processor is configured to control filament formation and filament destruction such that the period during which no filament is present between the electrode pairs is longer than the period during which the filament is present between the electrode pairs.

[0158] In some embodiments, at least one processor is further configured to temporally separate continuous filament discharge intervals by interleaving dwell intervals in which plasma filaments are not present between electrode pairs, such that the average length of the interleaved dwell intervals is at least 10 times the average duration of the multiple discharge intervals.

[0159] In some embodiments, at least one processor is configured to control the supply rate of carbon dioxide so that it has a longitudinal flow rate of 0.1 liters / min to 50 liters / min.

[0160] In some embodiments, the reactor further includes at least one gas flow control element configured to impart a rotational component of motion to the carbon dioxide supply, the rotational component of motion being sufficient to displace carbon dioxide molecules in the carbon dioxide supply by a distance greater than or equal to the average diameter of the plasma filaments generated between a plurality of plasma discharge intervals.

[0161] In some embodiments, the average length of the interleaved dwell interval is at least 50 times the average duration of the filament formation interval.

[0162] In some embodiments, the average length of the interleaved dwell interval is at least 100 times the average duration of the multiple filament formation intervals.

[0163] In some embodiments, the generation of plasma filaments occurs at a rate of at least 50 kHz.

[0164] In some embodiments, the generation of plasma filaments occurs at a rate of at least 100 kHz. CO 2 Exemplary reuse of surplus energy to reduce emissions

[0165] In some embodiments, a plasma generator may be installed at the outlet of an industrial plant to power a plasma generator that decomposes CO2 using surplus energy from the industrial plant.

[0166] In some embodiments, a system is provided for using surplus energy in an industrial process to reduce carbon dioxide emissions generated by the industrial process, comprising: a plasma generator including an electrode pair that is connectable to a surplus energy source and electrically connected to a power source; an inlet that links the plasma generator to a carbon dioxide outlet of the industrial process, allowing carbon dioxide emissions from the industrial process to flow into the region of the electrode pair; and a power source configured to supply energy to the plasma generator to cause a series of plasma filaments to form and interrupt each filament by extinguishing it before another filament can form, thereby converting the carbon dioxide in the region of the electrode pair into carbon and oxygen.

[0167] In some embodiments, a system is provided for using surplus energy in an industrial process to reduce carbon dioxide emissions generated by the industrial process, comprising: a plasma generator including an electrode pair that is connectable to a surplus energy source and electrically connected to a power source; an inlet that associates the plasma generator with a carbon dioxide outlet of the industrial process to allow carbon dioxide emissions from the industrial process to flow into the region of the electrode pair; and at least one processor for controlling the supply of energy to the plasma generator to cause a series of plasma filaments to form and interrupt each filament by extinguishing it before another filament is formed, thereby converting the carbon dioxide in the region of the electrode pair into carbon and oxygen.

[0168] In some embodiments, the time between the disappearance of the first filament and the formation of the second filament is at least 50 times the duration of the first or second filament. Exemplary plasma generation XeF 2

[0169] In some embodiments, a potentially important use case for the disclosed plasma reactor is the production of xenon fluoride by a plasma-assisted combination of methane and xenon.

[0170] In some embodiments, a plasma reactor is provided for producing xenon fluoride, comprising: a xenon fluoride reaction chamber defining a gas flow path; at least one inlet within the reaction chamber configured to supply amounts of carbon fluoride gas and xenon gas to the gas flow path; an electrode pair positioned within the gas flow path; a power supply configured to generate a time-varying voltage between the electrode pair, configured to enable the generation of plasma filaments between the electrode pair, and to control the voltage supplied between the electrode pair in a time-varying manner to repeatedly form and extinguish plasma filaments between the electrodes, such that the plasma filaments interact with the xenon gas and carbon fluoride gas when the plasma filaments are present between the electrode pair, and the interaction causes the formation of xenon fluoride; and at least one outlet within the reaction chamber configured to discharge xenon fluoride from the reaction chamber.

[0171] In some embodiments, a plasma reactor is provided for producing xenon fluoride, comprising: a xenon fluoride reaction chamber defining a gas flow path; at least one inlet within the reaction chamber configured to supply amounts of carbon fluoride gas and xenon gas to the gas flow path; an electrode pair positioned within the gas flow path; a power supply; at least one processor configured to generate a time-varying voltage between the electrode pair, configured to enable the generation of plasma filaments between the electrode pair, and to control the voltage supplied between the electrode pair in a time-varying manner to repeatedly form and extinguish plasma filaments between the electrodes, such that the plasma filaments interact with the xenon gas and carbon fluoride gas when the plasma filaments are present between the electrode pair, and the interaction causes the formation of xenon fluoride; and at least one outlet within the reaction chamber configured to discharge xenon fluoride from the reaction chamber.

[0172] In some embodiments, the generated xenon fluoride contains XeF2.

[0173] In some embodiments, the supply of carbon fluoride gas includes CF4 (tetrafluorocarbon).

[0174] In some embodiments, at least one processor is further configured to control the flow of a gas mixture including a supply of xenon gas and a supply of carbon fluoride gas having a longitudinal flow velocity along a gas channel of 0.1 liters / min to 50 liters / min.

[0175] In some embodiments, the reactor further includes at least one gas flow control element configured to impart a rotational component of motion to a gas mixture including a supply of xenon gas and a supply of carbon fluoride gas, the rotational component of motion being sufficient to displace molecules in the gas mixture by a distance greater than or equal to the average diameter of the plasma filaments generated between a plurality of plasma discharge intervals.

[0176] In some embodiments, at least one processor is further configured to temporally separate continuous filament formation intervals by interleaving dwell intervals in which plasma filaments are not present between electrode pairs, such that the average length of the interleaved dwell intervals is at least 10 times the average duration of the multiple filament formation intervals.

[0177] In some embodiments, the average length of the interleaved dwell interval is at least 50 times the average duration of the multiple discharge intervals.

[0178] In some embodiments, the average length of the interleaved dwell interval is at least 100 times the average duration of the multiple discharge intervals.

[0179] In some embodiments, the generation of plasma filaments occurs at a rate of at least 50 kHz.

[0180] In some embodiments, the generation of plasma filaments occurs at a rate of at least 100 kHz. Example plasma-generated synthesis gas

[0181] In some embodiments, a further potentially important use case for the disclosed plasma reactor is synthesis gas production, which uses about half the energy of current microwave systems.

[0182] In some embodiments, a plasma reactor is provided for generating synthesis gas, comprising: a synthesis gas reaction chamber defining a gas flow path; at least one inlet within the reaction chamber configured to supply into the gas flow path a supply of a first gas containing carbon and oxygen and a second gas containing hydrogen; an electrode pair positioned within the gas flow path; a power supply configured to generate and vary a voltage between the electrode pair over time, causing the plasma filament to repeatedly form and extinguish between the electrodes when the plasma filament is present between the electrode pair, such that the plasma filament interacts with the first and second gases, and the interaction causes the synthesis gas to form; and at least one outlet within the reaction chamber configured to discharge the synthesis gas from the reaction chamber.

[0183] In some embodiments, a plasma reactor is provided for generating synthesis gas, comprising: a synthesis gas reaction chamber defining a gas flow path; at least one inlet within the reaction chamber configured to supply into the gas flow path a supply of a first gas containing carbon and oxygen and a second gas containing hydrogen; an electrode pair positioned within the gas flow path; a power supply; at least one processor configured to change the voltage between the electrodes and generate a voltage over time such that the plasma filament interacts with the first and second gases when the plasma filament is present between the electrode pair, causing the plasma filament to repeatedly form and extinguish between the electrodes, the interaction causing the synthesis gas to form; and at least one outlet within the reaction chamber configured to discharge the synthesis gas from the reaction chamber.

[0184] In some embodiments, the first gas includes CO2.

[0185] In some embodiments, the second gas includes CH4.

[0186] In some embodiments, the synthesis gas includes a mixture of carbon monoxide and hydrogen.

[0187] In some embodiments, the mixture of the first gas and the second gas has a longitudinal flow velocity of 0.1 liters / min to 50 liters / min along the gas flow path.

[0188] In some embodiments, at least one processor is further configured to temporally separate continuous filament formation intervals by interleaving dwell intervals in which plasma filaments are not present between electrode pairs, such that the average length of the interleaved dwell intervals is at least 10 times the average duration of the multiple filament formation intervals.

[0189] In some embodiments, the reactor further includes at least one gas flow control element configured to impart a rotational component of motion to a gas mixture comprising a first gas and a second gas, the rotational component of motion being sufficient to displace molecules in the gas mixture by a distance greater than or equal to the average diameter of the plasma filaments generated between a plurality of plasma discharge intervals.

[0190] In some embodiments, the average length of the interleaved dwell interval is at least 50 times the average duration of the multiple filament formation intervals.

[0191] In some embodiments, the average length of the interleaved dwell interval is at least 100 times the average duration of the multiple filament formation intervals.

[0192] In some embodiments, the generation of plasma filaments occurs at a rate of at least 50 kHz.

[0193] In some embodiments, the generation of plasma filaments occurs at a rate of at least 100 kHz.

[0194] The following description presents some additional examples according to embodiments of the present disclosure. Example 1

[0195] An exemplary process for converting CO2 to CO and oxygen, such as CO2 → CO + 1 / 2O2, was demonstrated using a pulsed plasma chemical reactor. First, CO2 was injected into a plasma reactor having two electrodes (anode and cathode) coaxially inserted into a quartz cylinder. Both electrodes had the shape shown in FIG. 17(11). Each electrode was fabricated as a copper cylinder having a tungsten rod. In both electrodes, the gas flow passes through the central hole of the copper part.

[0196] The power output section was connected to the electrodes. The output capacitor was 300 pF. In this way, the repetitive formation and disappearance of high-temperature plasma filaments were obtained. The lifetime of the plasma filaments was about 300 nanoseconds. The repetition frequency was 60 kHz. The desired gas velocity in the reactor was achieved by using a recirculating gas pump.

[0197] The parameters of the experiment are as follows.

[0198] Injected CO2 flow rate: 1.2 m 3 / h

[0199] Power output of the power supply: 900 W

[0200] Recirculating pump flow rate: 30 m 3 / h

[0201] Inner diameter of the quartz chamber: 40 mm

[0202] The concentration of the generated gas is as follows.

[0203] CO: 15%

[0204] O2: 7.5% Example 2

[0205] An exemplary process for converting CO2 to CO and oxygen in reactions such as CO2 → CO + 1 / 2O2 was demonstrated using a pulsed plasma chemical reactor. Initial CO2 was injected into a plasma reactor having two electrodes (anode and cathode) coaxially inserted into a quartz cylinder. Both electrodes had the shape shown in Figure 17(10). Each electrode was made of copper. In both electrodes, the gas flow passed through the central hole of the copper portion. The power output was connected to the electrodes. The output capacitor was 300 pF. In this way, repeated formation and extinction of high-temperature plasma filaments were obtained. The lifetime of the plasma filaments was approximately 300 nanoseconds. The repetition frequency was 60 kHz. The desired gas velocity in the reactor was achieved by using a recirculation gas pump.

[0206] The experimental parameters are as follows:

[0207] Injection CO2 flow rate: 1.2m 3 / h

[0208] Power output: 1200W

[0209] Recirculation pump flow rate: 30 m³ 3 / h

[0210] Quartz chamber inner diameter: 40 mm

[0211] The concentrations of the generated gases are as follows:

[0212] CO: 13%

[0213] O2: 6.5% Example 3

[0214] A process for converting CO2 to CO and oxygen in the reaction CO2 → CO + 1 / 2O2 was demonstrated using a pulsed plasma chemical reactor. Initial CO2 was injected into a plasma reactor having two electrodes (anode and cathode) coaxially inserted into a quartz cylinder. The cathode electrode had the shape shown in Figure 17(10). The cathode was made of copper. The anode had the shape shown in Figure 17(11). The anode was fabricated as a copper cylinder with a tungsten rod. In both electrodes, the gas flow passed through the central hole of the copper portion. The power output was connected to the electrodes. The output capacitor was 300 pF. In this way, repeated formation and extinction of high-temperature plasma filaments were obtained. The lifetime of the plasma filaments was approximately 300 nanoseconds. The repetition frequency was 60 kHz. The desired gas velocity in the reactor was achieved by using a recirculation gas pump.

[0215] The experimental parameters are as follows:

[0216] Injection CO2 flow rate: 1.2m 3 / h

[0217] Power output: 950W

[0218] Recirculation pump flow rate: 30 m³ 3 / h

[0219] Quartz chamber inner diameter: 40 mm

[0220] The concentrations of the generated gases are as follows:

[0221] CO: 14%

[0222] O2:7% Example 4

[0223] A process for converting CO2 to CO and oxygen in the reaction CO2 → CO + 1 / 2O2 was demonstrated using a pulsed plasma chemical reactor. Initial CO2 was injected into a plasma reactor having two electrodes (anode and cathode) coaxially inserted into a quartz cylinder. Both electrodes had the shape shown in Figure 17(11). Each electrode was fabricated as a copper cylinder with a tungsten rod. In both electrodes, the gas flow passed through the central hole of the copper portion. The power output was connected to the electrodes. The output capacitor was 300 pF. In this way, repeated formation and extinction of high-temperature plasma filaments were obtained. The lifetime of the plasma filament was approximately 300 nanoseconds. The repetition frequency was 60 kHz. The desired gas velocity in the reactor was achieved by using a recirculation gas pump.

[0224] The experimental parameters are as follows:

[0225] Injection CO2 flow rate: 1.2m 3 / h

[0226] Power output: 930W

[0227] Recirculation pump flow rate: 20 m³ 3 / h

[0228] Quartz chamber inner diameter: 40 mm

[0229] The concentrations of the generated gases are as follows:

[0230] CO: 15%

[0231] O2: 7.5% Example 5

[0232] A process for converting CO2 to CO and oxygen in the reaction CO2 → CO + 1 / 2O2 was demonstrated using a pulsed plasma chemical reactor. Initial CO2 was injected into a plasma reactor having two electrodes (anode and cathode) coaxially inserted into a quartz cylinder. Both electrodes had the shape shown in Figure 17(11). Each electrode was fabricated as a copper cylinder with a tungsten rod. In both electrodes, the gas flow passed through the central hole of the copper portion. The power output was connected to the electrodes. The output capacitor was 300 pF. In this way, repeated formation and extinction of high-temperature plasma filaments were obtained. The lifetime of the plasma filament was approximately 300 nanoseconds. The repetition frequency was 60 kHz. The desired gas velocity in the reactor was achieved by using a recirculation gas pump.

[0233] The experimental parameters are as follows:

[0234] Injection CO2 flow rate: 1.2m 3 / h

[0235] Power output: 1000W

[0236] Recirculation pump flow rate: 15 m³ 3 / h

[0237] Quartz chamber inner diameter: 40 mm

[0238] The concentrations of the generated gases are as follows:

[0239] CO: 14%

[0240] O2: 7.0% Example 6

[0241] A process for converting CO2 to CO and oxygen in the reaction CO2 → CO + 1 / 2O2 was demonstrated using a pulsed plasma chemical reactor. Initial CO2 was injected into a plasma reactor having two electrodes (anode and cathode) coaxially inserted into a quartz cylinder. Both electrodes had the shape shown in Figure 17(11). Each electrode was fabricated as a copper cylinder with a tungsten rod. In both electrodes, the gas flow passed through the central hole of the copper portion. The power output was connected to the electrodes. The output capacitor was 300 pF. In this way, repeated formation and extinction of high-temperature plasma filaments were obtained. The lifetime of the plasma filament was approximately 300 nanoseconds. The repetition frequency was 60 kHz. The desired gas velocity in the reactor was achieved by using a recirculation gas pump.

[0242] The experimental parameters are as follows:

[0243] Injection CO2 flow rate: 1.2m 3 / h

[0244] Power output: 900W

[0245] Recirculation pump flow rate: 30 m³ 3 / h

[0246] Quartz chamber inner diameter: 40 mm

[0247] The concentrations of the generated gases are as follows:

[0248] CO: 15%

[0249] O2: 7.5% Example 7

[0250] Process of converting a mixture of 50% CO2 and 50% CH4 into synthesis gas (mixture of CO and H2) in the reaction CO2 + CH4 → 2CO + 2H2 using a pulsed plasma chemical reactor. First, CO2 was injected into a plasma reactor having two electrodes (anode and cathode) coaxially inserted into a quartz cylinder. Both electrodes had the shape shown in Fig. 17(11). Each electrode was fabricated as a copper cylinder having a tungsten rod. In both electrodes, the gas flow passed through the central hole of the copper part. The power output section was connected to the electrodes. The output capacitor was 300 pF. In this way, repetitive formation and disappearance of high-temperature plasma filaments were obtained. The lifetime of the plasma filaments was about 200 nanoseconds. The repetition frequency was 60 kHz. The desired gas velocity in the reactor was achieved by using a recirculation gas pump.

[0251] The parameters of the experiment are as follows.

[0252] Injected CO2 flow rate: 1.2 m 3 / h

[0253] Injected CH4 flow rate: 1.2 m 3 / h

[0254] Power output of the power supply: 1300 W

[0255] Recirculation pump flow rate: 30 m 3 / h

[0256] Inner diameter of the quartz chamber: 40 mm

[0257] The concentration of the generated gas is as follows.

[0258] CO: 15%

[0259] H2: 15% Example 8

[0260] Using a pulsed plasma chemical reactor, we demonstrated a process to convert a mixture of 50% CO2 and 50% CH4 into synthesis gas (a mixture of CO and H2) in the reaction CO2 + CH4 → 2CO + 2H2. The initial CO2 was injected into a plasma reactor having two electrodes (anode and cathode) coaxially inserted into a quartz cylinder. Both electrodes had the shape shown in Figure 17(11). Each electrode was fabricated as a copper cylinder with a tungsten rod. In both electrodes, the gas flow passed through the central hole of the copper portion. The power output was connected to the electrodes. The output capacitor was 300 pF. In this way, repeated formation and extinction of high-temperature plasma filaments were obtained. The lifetime of the plasma filament was approximately 200 nanoseconds. The repetition frequency was 60 kHz. The desired gas velocity in the reactor was achieved by using a recirculation gas pump.

[0261] The experimental parameters are as follows:

[0262] Injection CO2 flow rate: 1.2m 3 / h

[0263] Injection CH4 flow rate: 1.2m 3 / h

[0264] Power output: 1100W

[0265] Recirculation pump flow rate: 20 m³ 3 / h

[0266] Quartz chamber inner diameter: 40 mm

[0267] The concentrations of the generated gases are as follows:

[0268] CO: 15%

[0269] H2:15% Example 9

[0270] Using a pulsed plasma chemical reactor, the process of converting a mixture of 50% CO2 and 50% CH4 into syngas (a mixture of CO and H2) in the reaction CO2 + CH4 → 2CO + 2H2 was demonstrated. First, the initial CO2 was injected into a plasma reactor having two electrodes (anode and cathode) coaxially inserted into a quartz cylinder. Both electrodes were assumed to have the shape shown in Fig. 17(11). Each electrode was fabricated as a copper cylinder having a tungsten rod. In both electrodes, the gas flow passes through the central hole of the copper part. The power output section was connected to the electrodes. The output capacitor was 300 pF. In this way, the formation and disappearance of repetitive high-temperature plasma filaments were obtained. The lifetime of the plasma filament was about 200 nanoseconds. The repetition frequency was 60 kHz. The desired gas velocity in the reactor was achieved by using a recycle gas pump.

[0271] The parameters of the experiment are as follows.

[0272] Injected CO2 flow rate: 1.2 m 3 / h

[0273] Injected CH4 flow rate: 1.2 m 3 / h

[0274] Power output of the power supply: 900 W

[0275] Recycle pump flow rate: 10 m 3 / h<00 / / h

[0276] Inner diameter of the quartz chamber: 40 mm

[0277] The concentration of the generated gas is as follows.

[0278] CO: 15%

[0279] H2: 15% Example 10

[0280] Using a pulsed plasma chemical reactor, we demonstrated a process to convert a mixture of 50% CO2 and 50% CH4 into synthesis gas (a mixture of CO and H2) in the reaction CO2 + CH4 → 2CO + 2H2. The initial CO2 was injected into a plasma reactor having two electrodes (anode and cathode) coaxially inserted into a quartz cylinder. Both electrodes had the shape shown in Figure 17(11). Each electrode was fabricated as a copper cylinder with a tungsten rod. At both electrodes, the gas flow passed through an additional tangential hole to generate a swirling flow. The central hole was closed.

[0281] The power supply output was connected to the electrodes. The output capacitor was set to 300 pF. In this manner, the repeated formation and extinction of high-temperature plasma filaments was achieved. The lifetime of the plasma filaments was approximately 200 nanoseconds. The repetition frequency was 60 kHz. The desired gas velocity in the reactor was achieved by using a recirculation gas pump.

[0282] The experimental parameters are as follows:

[0283] Injection CO2 flow rate: 1.2m 3 / h

[0284] Injection CH4 flow rate: 1.2m 3 / h

[0285] Power output: 1100W

[0286] Recirculation pump flow rate: 30 m³ 3 / h

[0287] Quartz chamber inner diameter: 40 mm

[0288] The concentrations of the generated gases are as follows:

[0289] CO: 15%

[0290] H2:15% Example 11

[0291] Using a pulsed plasma chemical reactor, we demonstrated a process to convert a mixture of 50% CO2 and 50% CH4 into synthesis gas (a mixture of CO and H2) in the reaction CO2 + CH4 → 2CO + 2H2. The initial CO2 was injected into a plasma reactor having two electrodes (anode and cathode) coaxially inserted into a quartz cylinder. Both electrodes had the shape shown in Figure 17(11). Each electrode was fabricated as a copper cylinder with a tungsten rod. At both electrodes, the gas flow passed through an additional tangential hole to generate a swirling flow. The central hole was closed. The power output was connected to the electrodes. The output capacitor was 300 pF. In this way, repeated formation and extinction of high-temperature plasma filaments were obtained. The lifetime of the plasma filament was approximately 200 nanoseconds. The repetition frequency was 60 kHz. The desired gas velocity in the reactor was achieved by using a recirculation gas pump.

[0292] The experimental parameters are as follows:

[0293] Injection CO2 flow rate: 1.2m 3 / h

[0294] Injection CH4 flow rate: 1.2m 3 / h

[0295] Power output: 900W

[0296] Recirculation pump flow rate: 20 m³ 3 / h

[0297] Quartz chamber inner diameter: 40 mm

[0298] The concentrations of the generated gases are as follows:

[0299] CO: 15%

[0300] H2:15%

[0301] Examples of reactor configurations and operating parameters (along with exemplary results obtained during experiments) are shown in the following sections. Example 12

[0302] We demonstrated the production of acetylene from a 70 / 30 methane / hydrogen mixture at atmospheric pressure.

[0303] The gas flow rate (recirculation line) was set to 20 m / h. The cathode had a tungsten pin with a variable length that decreased in the direction of tangential flow. The anode had six tangential holes, each with a diameter of 6 mm. The dielectric breakdown frequency was set to 52 kHz. The gap between the cathode pin and the anode pin was set to 40 mm. The calculated tangential velocity of the gas in the electrode zone was 30 m / s, which is f × 5 × 10⁻¹⁰. -4 Faster than 25 m / s

[0304] The power supply is based on an IGBT bridge circuit diagram and a high-voltage transformer mounted on a pair of half-wave rectifiers having high-voltage diodes and capacitors, with one rectifier positively charging the positive terminal and the other negatively charging the negative terminal, and an inductor and capacitor are installed in series with the rectifiers (Figure 12).

[0305] During the experiment, plasma position rotation was observed, and the stable dielectric breakdown voltage was within the 9-10 kV range. The energy transfer efficiency from the power source to the plasma was 82%. The plasma energy cost for acetylene molecule generation was 8 eV per molecule. Example 13

[0306] We demonstrated the production of acetylene from a 70 / 30 methane / hydrogen mixture at atmospheric pressure.

[0307] The gas flow rate (recirculation line) was set to 10 m / h. The cathode had a tungsten pin with a variable length that decreased in the direction of tangential flow. The anode had six tangential holes, each with a diameter of 6 mm. The dielectric breakdown frequency was set to 52 kHz. The gap between the cathode pin and the anode pin was set to 40 mm. The calculated tangential velocity of the gas in the electrode zone was 15 m / s, which is f × 5 × 10⁻¹⁰. -4 Slower than 25 m / s

[0308] The power supply is based on an IGBT bridge circuit diagram and a high-voltage transformer mounted on a pair of half-wave rectifiers having high-voltage diodes and capacitors, with one rectifier positively charging the positive terminal and the other negatively charging the negative terminal, and an inductor and capacitor are installed in series with the rectifiers (Figure 12).

[0309] During the experiment, no rotation of the plasma position was observed, and adhesion of plasma filaments to the electrode pins was detected. The dielectric breakdown voltage was in the range of 6-10 kV. The energy transfer efficiency from the power source to the plasma was 65%. The plasma energy cost for acetylene molecule generation was 8.5 eV per molecule. Example 14

[0310] The dissociation of CO2 at atmospheric pressure was demonstrated. The gas flow rate (recirculation line) was set to 20 m / h. The cathode had a tungsten pin with a variable length that decreased in the direction of tangential flow. The anode had six tangential holes, each with a diameter of 6 mm. The dielectric breakdown frequency was set to 52 kHz. The gap between the cathode pin and the anode pin was set to 40 mm. The calculated tangential velocity of the gas in the electrode zone was 30 m / s, which is f × 5 × 10⁻¹⁰. -4 Faster than 25 m / s

[0311] The power supply was based on an IGBT semibridge circuit diagram and a high-voltage transformer with a primary winding having an intermediate point. The transformer was mounted on a pair of half-wave rectifiers having high-voltage diodes and capacitors, with one rectifier positively charging its positive terminal and the other negatively charging its negative terminal, and an inductor and capacitor were installed in series with the rectifiers (Figure 12).

[0312] During the experiment, plasma position rotation was observed, and no adhesion of plasma filaments to the electrode pins was detected. The dielectric breakdown voltage was in the range of 8-9 kV. The energy transfer efficiency from the power source to the plasma was 80%. The plasma energy cost for CO generation was 4.2 eV per molecule. Example 15

[0313] The dissociation of CO2 at atmospheric pressure was demonstrated. The discharge chamber had four channels (Figure 10). The gas flow rate (recirculation line) was 20 m / h. The cathode had a tungsten pin with a variable length that decreased in the direction of tangential flow. The anode had six tangential holes, each with a diameter of 6 mm. The dielectric breakdown frequency was 12 kHz. The gap between the cathode pin and the anode pin was 40 mm. The calculated tangential velocity of the gas in the electrode zone was 8 m / s, which is f × 5 × 10⁻¹⁰. -4 Faster than 6 m / s

[0314] The power supply was based on an IGBT semibridge circuit diagram and a high-voltage transformer with a primary winding having an intermediate point. The transformer was mounted on four pairs of half-wave rectifiers, each having a high-voltage diode and a capacitor. One rectifier in each pair positively charged its positive terminal, and the other rectifier negatively charged its negative terminal. An inductor and a capacitor were connected in series with each pair of rectifiers (Figure 13). In Figure 13, 1301 represents an inductor (5.5 mHn), 1302 represents the -30 kV point, 1303 represents the +30 kV point, 1304 represents a power module, 1305 represents a secondary winding (220 turns), 1306 represents a primary winding (3 turns), 1307 represents the +500 V point, 1308 represents an IGBT module (CM200DU-24NFH), 1309 represents an IGBT module (CM200DU-24NFH), 1310 represents a capacitor (6 x 820 μF, 200 V), 1311 represents a diode bridge (4 x 60 EPF12), 1312 represents a driver, and 1313 represents a variac (110 V, 20 A).

[0315] During the experiment, plasma position rotation was observed, and no adhesion of plasma filaments to the electrode pins was detected. The dielectric breakdown voltage was in the range of 8-9 kV. The energy transfer efficiency from the power source to the plasma was 81%. The plasma energy cost for CO generation was 4.1 eV per molecule. Example 16

[0316] The dissociation of NH4 at atmospheric pressure was demonstrated. The gas flow rate (recirculation line) was set to 20 m / h. The cathode had a tungsten pin with a variable length that decreased in the direction of tangential flow. The anode had six tangential holes, each with a diameter of 6 mm. The dielectric breakdown frequency was set to 52 kHz. The gap between the cathode pin and the anode pin was set to 40 mm. The calculated tangential velocity of the gas in the electrode zone was 30 m / s, which is f × 5 × 10⁻¹⁰. -4 Faster than 25 m / s

[0317] The power supply was based on an IGBT semibridge circuit diagram and a high-voltage transformer having a primary winding with an intermediate point. The transformer was mounted on a pair of half-wave rectifiers consisting of high-voltage diodes and capacitors, with one rectifier positively charging its positive terminal and the other negatively charging its negative terminal, and an inductor and capacitor were installed in series with the rectifiers (Figure 12).

[0318] During the experiment, plasma position rotation was observed, and no adhesion of plasma filaments to the electrode pins was detected. The dielectric breakdown voltage was in the range of 9–10 kV. The energy transfer efficiency from the power source to the plasma was 80%. The plasma energy cost for NH4 dissociation was 3.5 eV per molecule.

Claims

1. A plasma chemical reactor that generates nanosecond pulsed discharges, One or more cylindrical channels having a gas injection and gas discharge system, High-voltage positive electrode and high-voltage negative electrode within each channel, It comprises a gas swirling system within each channel for increasing the local tangential gas velocity near the electrode end, The frequency of the pulse discharge generation is f. The tangential gas velocity is f × 5 × 10 －３ A plasma chemical reactor operating at speeds faster than m / s.

2. The gas swirling system according to claim 1, comprising an auger-shaped electrode isolator, tangential channels in one or more electrodes, and tangential channels in the gas injection system and / or the gas discharge system.

3. The system according to claim 1, wherein each positive electrode and each negative electrode has a cylindrical shape, and at least one electrode has a tangential channel within the electrode body and a circular row of rods of equal length on a flat end, and at least one electrode that does not have a tangential channel has a circular row of rods having a length decreasing along the direction of gas rotation.

4. The system according to claim 1, wherein the power supply provides an AC voltage to the positive and negative terminals of each N channel by N pairs of half-wave rectifiers having high-voltage diodes and capacitors, one rectifier of each pair positively charges the positive terminal and the other rectifier negatively charges the negative terminal.

5. The system according to claim 4, wherein a high-voltage inductor and / or a high-voltage capacitor are connected in series with the diode of each half-wave rectifier.

6. The power supply includes a half-wave flyback, according to claim 4.

7. The system according to claim 5, wherein the power supply includes a full-wave push-pull circuit having an insulated-gate bipolar transistor (IGBT) semibridge.

8. The system according to claim 5, wherein the power supply is a full-wave push-pull circuit having an IGBT semibridge with an intermediate point transformer primary winding.

9. The system according to claim 5, wherein the power supply is a full-wave push-pull having an IGBT bridge.

10. The system according to claim 1, wherein a CO2-containing gas is supplied to the inlet of the plasma chemical reactor, and the CO2 is converted into CO and oxygen by the plasma.

11. The system according to claim 1, wherein a gas containing a mixture of CO2 and methane is supplied to the inlet of the plasma chemical reactor, and the CO2 and methane are converted into a synthesis gas.

12. The system according to claim 1, wherein a methane-containing gas is supplied to the inlet of the plasma chemical reactor, and the methane is converted into acetylene and hydrogen.

13. The system according to claim 1, wherein an H2S-containing gas is supplied to the inlet of the plasma chemical reactor, and the H2S is converted into sulfur and hydrogen.

14. The system according to claim 1, wherein an ammonia-containing gas is supplied to the inlet of the plasma chemical reactor, and the ammonia is converted into nitrogen and hydrogen.

15. The system according to claim 1, wherein a gas containing a mixture of nitrogen and hydrogen is supplied to the inlet of the plasma chemical reactor, and the nitrogen and hydrogen are converted into ammonia.

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