Philip G. Rutberg

Plasma based waste treatment and energy production

During the past centuries, industrial processes and energy conversion plants have shown no or little care for environmental quality. The result is a huge accumulation of pollution and hazardous by-products, left as a heritage for the present and future generations. Recuperation of by-products or thermal energy is not only motivated by cost saving, but also by resource saving considerations. Environmental awareness is more than staying within the lines of the existing regulations.By the application of a plasma based system to a wide range of possible feedstocks which are CO2 neutral, a clean syngas of high caloric value is produced from the organic substances simultaneously with a non-leachable vitrified lava from the inorganic substances. The results will provide the advanced technology for the environmentally friendly treatment of hazardous wastes, biomass and low grade fuel. The driving force behind the task is to give priority to environmental quality at affordable costs. Thus, the investigation of ways to increase the efficiency of the process is very important. A plasma based remediation system is the only technology that prevents undesired pollution in the by-products and end product (such as syngas or other gases). The problem to be solved is twofold: recuperate clean energy from waste and renewables without pollution at affordable costs. Such a technique fulfils the objectives of sustainable development.Today, one of the main reasons that restricts the use of plasma based methods is the cost of electrical energy. The crucial element is the plasma torch performance. Hence, the physics of modern plasma torches is addressed in detail. The optimistic scenario holds the promise to provide 10?15% of the energy needs for the European Union (EU). Thus, the investigation of ways to increase the efficiency of the process is very important.

Electric Discharges and the Prolonged Microbial Resistance of Water

One of alternative methods of water disinfection is its treatment by pulsed electric discharges (PEDs). In this case, during the discharges, bacteria are destroyed by UV radiation with a significant share of energy in waves of 200-400 nm and by shock waves, which are formed at the initial stage of the discharge-column widening. This paper describes the electrophysical properties of PED in water, presents the results of an investigation of the physical, chemical, bactericidal, and fungicidal properties of treated water, and explains the prolonged microbial resistance of water (PMRW) - the phenomenon when bacteria continue to be destroyed for a long time (several months) after treatment by PED. The results of investigations make it possible to conclude that the PMRW is caused by the cooperative bactericidal action on microorganisms of both oxide nanoparticles of electrodes metal and positive ions emitted by the nanoparticles.

The Programmed Capacitor Storage Discharge and Other Factors Influencing on Launch Velocity and on Performance of an Electrodischarge Accelerator

Investigation of influence of some factors on launch velocity and efficiency of projectiles acceleration by means of the electrothermal and other accelerators supplying by electric energy is performed for a long time and gave many experimental results. Besides the next parameters of working gas as: pressure, temperature, molecular mass, degree of its contamination etc., the duration of the electric energy input in working gas (duration of the current pulse) influences on velocity and efficiency too. The changing of duration of the electric energy input by programming of capacitor storage discharge can be performed. The experiments, which were carried out, showed the next main results. The projectile velocity increases by 7-10% at the programmed discharge mode comparatively to the synchronous mode, although the energy inserted in the arc is equal for both modes. The efficiency of energy conversion from internal energy of working gas to the kinetic energy of the projectile at velocity of 2100 m/s increases from 15 to 17 %. Thus, to achieve equal projectile velocity the pulsed pressure at the programmed mode would be lower than the same parameter at the synchronous mode. That is very important, for example, at launching of projectiles containing penetrators of big elongation.

Investigation of anode and cathode jets influence on electric arc properties with current up to 500 kA

A number of phenomena connected with the formation of electrode jets in discharges in hydrogen at a current of 10/sup 5/-10/sup 6/ A, a current growth rate of 10/sup 10/ A/s, an initial pressure 0.1-4.0 MPa, and a discharge gap length of 5-40 mm were studied. After the secondary breakdown, the jets are observed through a discharge semitransparent channel, widening with velocity (4-7) /spl middot/ 10/sup 2/ m/s. Shockwave formation was detected at the interaction of jets with the surrounding gas and the opposite electrode. Plasma vapor pressure of metal near the end of the tungsten cathode 70 /spl mu/s after initiation of a discharge was 180 MPa. Thus, magnitude of brightness temperature was 59 /spl middot/ 10/sup 3/ K, with an average charge of ions-m~=3.1, and a concentration of metal vapors n=5.3/spl middot/10/sup 19/ cm/sup -3/. While those at the end of the anode 90 /spl mu/s after initiation of discharge: m~=2.6, n=7.4/spl middot/10/sup 19/ cm/sup -3/. Probable reasons of high-voltage drops near the electrodes (the summarized magnitude of which is /spl sim/1 kV) are discussed on the basis of experimental data. For the first time, the shadow method registered symmetric ejection of material from the all-cathode surface the maximum discharge current was observed.

Electric launch in Russia. A review of recent results

In this paper, we present some major research results in electric launch technology that have been obtained in Russia since 1996. The research program includes studies of the potential of railguns, electric discharge launchers, coil guns, and ETC guns. The main efforts of researchers are now focused on investigation of fundamental physical processes and phenomena that limit attainment of high velocities and acceptable efficiency of EM launchers.

Electrode Plasma Jets in Powerful Pulsed Discharge in High-Pressure Gas

Electrode plasma jets formation and structure in powerful pulsed gas discharge at high pressures were investigated. Typical experimental parameters were current amplitude of 100-700 kA, pulse duration of 150-500 μs, current rise rate of ~1010 A/s, initial gas pressure of 1-10 MPa under which intense electrode plasma jets is being formed. Discharge was initiated by wire explosion. The structure of jets was studied by different high-speed diagnostic methods. The jet is shown to consist of a central metal zone surrounded by a gas plasma sheath in which, gas in flowed from the surrounding discharge channel space. Electrode plasma jets play a major role in heat and mass transfer between discharge channel and the surrounding gas.

Improvements of Biomass Gasification Process by Plasma Technologies

The chapter is dedicated to a promising method of biomass treatment—plasma gasification. Increased temperatures and energy supply allows significantly increase the range of wastes and other carbonaceous materials which could be efficiently processed. Features of plasma usage in updraft and downdraft biomass gasification are described. Several promising renewable energy sources (wood, energy crops, wastes of livestock, and poultry industry) are examined for the usage in downdraft plasma gasification. The correlation of key parameters of biomass plasma gasification was studied in thermodynamic equilibrium approach along with syngas usage for liquid fuel production. Institute for Electrophysics and Electric Power RAS experimental installation is described. Its primary component is a downdraft plasma gasifier for processing of biomass and wastes. Its technical characteristics and functionality are described. A brief survey of existing pilot and industrial projects is given. Methods of energy supply into plasma chemical reactor are described. The review of powerful plasma torches for industrial application is represented. Experimental procedures and test results on biomass gasification by air-plasma are presented as well as the comparison with the calculated data.

Electric discharge parameters in high density gas

At the IPE RAS were continued the experiments on the two-stage facility to study the powerful electric discharge in high density hydrogen. Results of these investigations are very important for improvement of characteristics of pulsed plasma generators (PPG) which are the main part of electrodischarge, electrothermal and electrothermal-chemical launchers. In course of experiments the influence of current rise rate and initial particle density on arc parameters was investigated and bright temperature of arc outer layer was measured. These experiments were performed under the following conditions: charge voltage of capacitive storage -8.0-12.0 kV, stored energy -140-400 kJ, discharge current -200-600 kA, current rise rate -10/sup 9/-10/sup 10/ A/s. The maximum particle density n/sub max/, achieved after the adiabatic compression of gas was about 3.0/spl times/10/sup 22/ cm/sup -3/. It was revealed that increasing in current rise rate causes reducing of arc diameter and increasing of its temperature. Experiment results permit to define the electric parameters of arc (arc voltage, arc resistance and strength of field) sizes of arc channel and discharge current density. Obtained experimental data permit to calculate the main parameters of discharge such as: temperature of arc channel, plasma conductivity and density of charged particles in arc channel. It was shown that increasing in initial particle density and discharge current rise rate leads to the significant increasing of arc temperature.

X-Ray Flash Radiography System for High-Pressure Arc Diagnostic

The design of a new flash X-ray diagnostic system for the determination of metal vapor concentration in high-current discharges in high-pressure gas is presented. The system consists of a pulsed X-ray source with a hardness of 20-50 keV and an X-ray CCD camera. A high-voltage generator with a pulse duration of 50 ns was used. The new X-ray tube of through-target type was designed. Experimental research on the diagnostic of high-current discharges with a Z-pinch geometry was carried out. The parameters of the experiments are as follows: dJ/dt ~109 -1010 A/s, discharge current amplitudes up to 1 MA, and initial gas pressures of 2.5 kPa-35 MPa. Experimental data on the spatial metal vapor distribution in the discharge gap, provided by electrode erosion, were obtained.

Combined electro-discharge launcher working on hydrogen

The light-gas gun (LGG) is a standard tool for achieving high velocities. Its performance depends on the sound speed of a working gas, determined by its molecular weight and operational temperature. High temperature can be achieved by either adiabatic compression of the gas, or by electric arc heating. For high performance, the first requires seriously high pressure (more than 2000 MPa). The second has to heat the working gas to several thousands of degrees Kelvin, which can cause thermal erosion of launcher elements. We report new progress on a combined launcher, which employs a powder charge for first-stage adiabatic compression of a working gas, and subsequent electric arc heating. This operational mode provides higher system efficiency, and also reduced maximum gas temperature and pressure. A new model for the combined launcher, with improved mechanical strength and optical measurement windows, is described. Experiments employed a range of conditions: 10-15 MPa initial working gas pressure, 150-200 MPa predischarge pressure, maximum pulse pressure up to 500 MPa, and discharge currents of 300-500 kA at rates of dl/dt /spl sim/10/sup 10/A/s. Our best ballistic results were 2.5 km/s for a 7.5 gm projectile, and 4.2 km/s for a 1.7 gm projectile. Characteristics of electric discharge at hydrogen concentrations of (1.5-3.3)/spl times/10/sup 22/cm/sup -3/, and other test data, are presented.