Method and device for producing thermally non-equilibrium plasma in plasmachemical reactors

Abstract

FIELD: plasma technology.SUBSTANCE: invention relates to systems for producing thermally nonequilibrium plasma in plasma-chemical reactors. A device for generating thermally nonequilibrium plasma in plasma-chemical reactors comprises a solid-state pulse generator, including a controlled switch, a pulse transformer and a voltage source; a discharge oscillatory circuit, receiving energy from said generator and including a secondary winding of said pulse transformer, a separating capacitor and a load – a plasma-chemical reactor; an external control unit.EFFECT: obtaining a nonequilibrium plasma in any type of gas and their compounds, as well as obtaining a nonequilibrium plasma by regulating the level of pulsed power in the reactor.4 cl, 4 dwg

Description

[0001] Field of technology to which the invention relates

[0002] The invention relates to systems for producing thermally nonequilibrium plasma in plasma-chemical reactors. The claimed method and device enable the production of thermally nonequilibrium plasma in various gases and their compounds over a wide pressure range (from vacuum to atmosphere). The method and device can be used to create plasma-chemical generators.

[0003] Technology Level

[0004] The prior art discloses a solution under current patent No. 2553290 "DEVICE FOR PRODUCING NITRIC OXIDE", which relates to plasma chemistry, in particular to the technology of producing nitric oxide (NO) from a source gas containing at least nitrogen and oxygen using an electric discharge, and can be used in scientific research (experimental plasma studies), in biology (impact on biological objects) and medicine (inhalation NO therapy, as well as therapy for wound, inflammatory, vascular and other pathologies). The device for producing nitric oxide includes a discharge chamber, two high-voltage electrodes electrically insulated from each other, the first of which is made in the form of a disk with a central hole made with a thread for the inlet channel, and the second high-voltage electrode is made in the form of a wire loop installed along the axis of the discharge chamber, placed inside the discharge chamber in such a way,that between said electrodes there is an interelectrode space, an inlet and outlet channel, a gas filter, a pump of the source gas containing at least oxygen and nitrogen, an absorber, a gas analyzer, wherein the inlet of said pump is connected to the gas filter, the outlet of said pump is connected to the inlet channel, the inlet of said absorber is connected to the outlet channel, and the outlet of the absorber is connected to the gas analyzer, wherein a voltage pulse former with an adjustable repetition rate is additionally introduced, including a resonant inverter and electrically connected to the high-voltage electrodes and to the gas analyzer. The invention makes it possible to increase the reliability and simplify the device.

[0005] Also known is patent No. 2183474, "Method and Device for Generating an NO-Containing Gas Flow for Affecting a Biological Object," which has expired. The invention pertains to the field of medicine. The NO-containing gas flow is formed from a source gas containing at least oxygen and nitrogen, in a housing containing at least two electrodes insulated from each other, between which a stationary DC arc discharge is formed and maintained. The NO-containing gas flow is formed under the action of the arc discharge and is discharged through a cooled channel, which allows for the capture of nitric oxide in the flow, bringing the temperature of the outgoing flow and the NO content therein to values ​​​​necessary for an effective therapeutic effect on a biological object.

[0006] Also known is the invention under US Patent No. 6,955,790, "APPARATUS FOR PLASMA-CHEMICAL PRODUCTION OF NITROGEN MONOXIDE," which, unlike the proposed system, nitric oxide synthesis is accomplished in a barrier discharge plasma. The method and apparatus for plasma-chemical production of nitrogen monoxide are used to produce an inhalation gas enriched with nitrogen monoxide for medical purposes. Nitrogen monoxide production is achieved through the use of a dielectric barrier discharge created in a process gas containing nitrogen and oxygen.

[0007] Disclosure of invention

[0008] The technical result of the invention is the ability to generate nonequilibrium plasma in any type of gas and its compounds, as well as by regulating the pulsed power level in the reactor. Ionization of the medium in the plasma-chemical generator results in the dissociation of molecules into individual atoms and the formation of new compounds. The plasma-chemical generator is an element of a resonant oscillatory electrical circuit. Energy is introduced into the circuit in short pulses.

[0009] The technical result of the invention consists in the possibility of producing a nonequilibrium plasma by exciting high-frequency oscillations in a resonant circuit containing a reactor. The level of pulsed power determines the plasma-chemical reaction process. The kinetics of chemical transformations are determined by the interaction of particles and the statistics of their ensemble behavior. By varying the pulsed power introduced into the reactor, it is possible to control the dynamics of particle collisions and, consequently, the kinetics of chemical reactions. And by varying the pulse frequency, it is possible to change the percentage of new compounds in the plasma-chemical reaction products.

[0010] A plasma-chemical reactor is a closed-volume structure containing a system of electrodes. The number of electrodes, their size, and geometry can vary depending on the purpose and design of the plasma-chemical reactor. The reactor is equipped with a feedstock (source gases) input system and a reaction product output system. Depending on the design and type of electrodes, various discharge types (corona, barrier, arc, spark, etc.) can be implemented.

[0011] The novelty of this method lies in the energy input system into the discharge volume. To generate a thermally nonequilibrium plasma occupying the entire reactor volume, energy is introduced in pulses of a specific, variable duration. The type of plasma-chemical reaction and the feedstock determine the pulse duration and energy. The pulse repetition frequency can vary from 1 Hz to 10 kHz. The upper frequency limit is determined by many parameters, including gas type, pressure, flow rate, etc. The main condition for producing a thermally nonequilibrium plasma is complete deionization of the gaseous medium before the next pulse. Pulse energy varies from 1 to 100 mJ. Selecting the appropriate modes allows for the generation of thermally nonequilibrium plasma over a wide range of parameters, including geometry, pressure, flow rate, and gas type.

[0012] Implementation of the invention

[0013] When using the device, the first stage involves injecting energy into the circuit using a two-winding inductive element. This element is a pulse transformer with a non-magnetic gap. The injected energy is dosed and controlled with each pulse.

[0014] Energy is introduced into the circuit as follows. At time T1 (Fig. 1 and Fig. 2), the low-voltage winding L1 of the pulse transformer is connected to a voltage source U, the current through which begins to gradually increase to a certain, specified value (the current amplitude determines the amount of energy introduced into the discharge). There is no current on the secondary side, since the voltage appearing on the secondary winding (the voltage level is determined by the transformation ratio of the pulse transformer) is insufficient to breakdown the interelectrode gap. At time T2 (Fig. 2), the electrical circuit opens.

[0015] The next stage of the process occurs when the electronic switch in the primary circuit opens. Simultaneously, the voltage polarity on the secondary side of the pulse transformer reverses, and its level rises sharply. At this point, the discharge is absent, its active resistance is infinite, and the system represents a series oscillatory circuit, in which voltage resonance occurs in the discharge volume.

[0016] High-frequency megahertz current oscillations occur in the circuit (Fig. 3) against the background of an applied high-voltage pulse. Since the medium is gaseous, breakdown and discharge formation occur. The discharge occupies virtually the entire volume of the discharge gap, and energy is released in the discharge (Fig. 4).

Claims

1. A device for generating thermally nonequilibrium plasma in plasma-chemical reactors, comprising: a solid-state pulse generator that includes a controlled switch, a pulse transformer and a voltage source; a discharge oscillatory circuit receiving energy from the said generator and including the secondary winding of the said pulse transformer, a separating capacitor and a load - a plasma-chemical reactor; external control unit.

2. A device for generating thermally nonequilibrium plasma in plasma-chemical reactors according to paragraph 1, the external control unit of which is manual without a microcontroller.

3. A device for generating thermally nonequilibrium plasma in plasma-chemical reactors according to paragraph 1, the external control unit of which is automated with a microcontroller.

4. A method for generating high-voltage, high-frequency pulses in a gaseous medium using the device from paragraph 1, consisting of three stages: the first stage consists of introducing energy into the oscillatory circuit, namely, at a given moment the low-voltage winding of the pulse transformer is connected to a voltage source, the current through which begins to gradually increase to a certain specified value, the second stage is to create a breakout, The third stage involves exciting resonant oscillations in the circuit and releasing energy in the load, which allows the formation of a discharge.

Images