Plasma chemical purification of flue gases using pulsed electron beams

The article presents the study of the pulsed electron beam propagation in oxygen and nitrogen. The researches were performed using the TEA-500 pulsed electron accelerator and drift tube. Parameters of the TEA-500 pulsed electron accelerator are as follows: the electron energy (varies) is 200-450 keV, the beam current is 10 kA, the half-amplitude current pulse duration is 60 ns, the pulse repetition rate is up to 10 Hz (in the pulse burst). The accelerator is equipped with the necessary means of diagnostics of the beam parameters: particle energy, current and current density, the total energy transferred by the beam. The drift tube includes a chamber consisting of two sections of reverse current shunts located along the entire length of the drift tube. The following precursors used N2 and O2. The specified types of gases were chosen as they are among the main components of the flue gases, whose treatment has been widely reported recently

Propagation of the pulsed electron beam of nanosecond duration in gas composition of high pressure

This paper presents the results of the investigation of the propagation of an electron beam in the high-pressure gas compositions (50, 300, and 760 Torr): sulfur hexafluoride and hydrogen, sulfur hexafluoride and nitrogen, sulfur hexafluoride and argon. The experiments have been performed using the TEA-500 laboratory accelerator. The main parameters of the accelerator are as follows: an accelerating voltage of 500 kV; an electron beam current of 10 kA; a pulse width at half maximum of 60 ns; a pulse energy of 200 J; a pulse repetition rate of up to 5 pulses per second, a beam diameter of 5 cm. The pulsed electron beam was injected into a 55 cm metal drift tube. The drift tube is equipped with three reverse-current shunts with simultaneous detecting of signals. The obtained results of the investigation make it possible to conclude that the picture of the processes occurring in the interaction of an electron beam in the high-pressure gas compositions is different from that observed in the propagation of the electron beam in the low-pressure gas compositions (1 Torr)

Influence of Cathode Diameter on the Operation of a Planar Diode with an Explosive Emission Cathode

This paper presents the results of experimental investigations into the current-voltage characteristics of a planar diode with an explosive emission cathode made from graphite. Studies were performed using a TEU-500 pulsed electron accelerator (350–500 keV, 100 ns, 250 J per pulse). Duration of diode operation, in a mode when electron current is limited by the emissive ability of the graphite cathode, is 15–20 ns. The contribution of the cathode periphery to total electron current appears only as an increase in the emissive surface area due to an expansion of explosive plasma. Investigations of an ion diode with a graphite cathode (plane and focusing geometry) were also carried out. Experiments were performed using a TEMP-4M ion accelerator, which forms two nanosecond pulses: the first negative pulse (150–200 kV, 300–600 ns) followed by the second positive (250–300 kV, 150 ns). Total diode current in the first pulse is well described by the Child-Langmuir law for electron current at a constant rate of plasma expansion, equal to 1.3 cm/μs. It is shown that for an area of flat cathode over 25 cm2, the influence of edge contribution does not exceed measurement error of total diode electron current (10%)

Electrospark method for obtaining nanopowders

In the paper, a metallic FexOy nanopowder was obtained by the electrospark method. The used electrospark installation consists of the electrode system, mobility system, system for measuring processing parameters (oscilloscope and current sensor, HV voltage divider, manovacuum meter), source of current pulses, vacuum system (vacuum pump, gas cylinders with working gas, gas routes, gas taps). The specific feature of the installation is the use of a power supply circuit of two generators with different voltage levels operating for one interelectrode gap. This generator circuit makes it possible to change the treatment parameters in wide ranges (pulse duration 10–100 ?s, pulse energy 0.1–0.6 J, pulse repetition rate 0.1–5 kHz). It will enable to choose the optimal ratio between the energy expended and the maximum yield of the product, as well as to study the influence of treatment parameters on the composition and properties of the resulting powder. The morphology and phase composition of the FexOy synthesized metal powder was studied

Optical properties of SixTiyCzOw composite nanopowder obtained by pulsed plasma chemical method

This paper presents the results of an experimental investigation on the optical properties of the SixTi<yCzOw nanopowders, produced by the pulsed plasma chemical method. Pulsed plasma chemical synthesis is realized on the laboratory stand, including a plasma chemical reactor (6 l) and TEA-500 electron accelerator. The parameters of the electron beam are as follows: 400-450 keV electron energy, 60 ns half-amplitude pulse duration, up to 200 J pulse energy, and 5 cm beam diameter. The spectrum of the diffuse reflection coefficient R(hv) was measured using the AvaSpec-2048-2 (Avantes) spectrometer with the AvaLight-DHS light source (deuterium and halogen-tungsten lamp) and an integrating sphere. The band gap of the obtained composite is 2.03–3.12 eV

Pulsed plasma chemical synthesis of SixCyOz composite nanopowder

SixCyOz composite nanopowder with an average size of particles about 10-50 nm was produced using the pulsed plasma chemical method. The experiments on the synthesis of nanosized composite were carried out using a TEA-500 pulsed electron accelerator. To produce a composite, SiCl[4], O[2], and CH[4] were used. The major part of experiments was conducted using a plasma chemical reactor (quartz, 140 mm diameter, 6 l volume). The initial reagents were injected into the reactor, then a pulsed electron beam was injected which initiated the chemical reactions whose products were the SixCyOz composite nanopowder. To define the morphology of the particles, the JEOL-II-100 transmission electron microscope (TEM) with an accelerating voltage of 100 kV was used. The substances in the composition of the composite nanopowder were identified using the infrared absorption optical spectrum. To conduct this analysis, the Nicolet 5700 FT-IR spectrometer was used

Investigation of the effect of condensed phase on the energy conditions for the initiation of the plasma-chemical process of flue gas cleaning by a pulsed electron beam

This work investigates the processes of dissipation of the charge and energy of a pulsed electron beam in gas compositions (nitrogen, carbon dioxide and oxygen) in the presence of ammonium sulphate and nitrate. A pulsed electron beam generated by the TEA500 accelerator (Tomsk, Russia) with an electron energy of up to 410 keV, a beam current of up to 5 kA (I0), and a half-amplitude voltage pulse duration of 60 ns was injected into a 46 cm long drift chamber filled with a gas mixture. The pulsed electron beam current (IF?) passing through the drift chamber was registered using a sectioned calorimeter with beam charge monitor function, and the efficiency of the current passage of the beam was determined as the ratio qF?/q0, where q0 is the beam charge measured at the place of its injection into the chamber drift. The pressure in the drift chamber varied (375, 560 and 760 Torr, humidity value 15% ± 5% and 50% ± 5%). The geometric dimensions of the plasma-chemical reactor for initiating plasma-chemical reactions of flue gas cleaning were determined