Optimisation of one stage electrostatic precipitator for welding fume filtration

AbstractIn addition to huge installations of electrostatic precipitators (ESP), as those employed for dust filtration in blast furnaces and cement factories, there are also small devices as the ones used for fume filtration in welding shops. The aim of this paper is to optimize the geometric characteristics and the electric operating conditions of a “one-stage” precipitator intended for the filtration of welding fumes. The experimental bench is composed of 2 units, each consisting in an horizontal wire (tungsten, diameter 0.1 mm), energized from a high-voltage supply (+15 kV, 5 mA), and equally distant from two vertical plate electrodes (aluminium, length 200 mm × variable width) connected to the ground. Two “one-factor-at-a-time” experiments paved the way for a composite experimental design that enabled the optimization of ESP geometry, i.e. the inter-electrode interval and width of the collecting electrodes

Experimental investigation of the dielectric barrier discharge using design of experiments

AbstractMany experimental and numerical studies were devoted to Dielectric Barrier Discharge (DBD) in air, but no mathematical models were proposed, either for current or for power. As they depend on several parameters, it is difficult to find a formula that considers many factors. The aim of this paper is first to make a brief comparison between surface and volume DBD, and second to model the current and power of a DBD in a “multipoints-plane” electrode system, using the methodology of experimental design. Three factors were considered: inter-electrode distance, distance between adjacent points, and thickness of the glass dielectric barrier. A double Composite Centred Faces experimental design (CCF) was carried out. The obtained results made it possible to propose mathematical models and, therefore to study interactions between various factors

Effect of shielded electrodes dimensions on corona charging systems

International audienceDual-type corona electrodes, consisting of a thin ionizing wire attached to a larger radius metallic cylinder, both connected to the same high-voltage supply, are widely used to generate corona discharges in several electrostatic processes such as charging granular materials in electrostatic separation and charging of fibrous media in the manufacturing processes of industrial air filters. The principal aim of this work is to experimentally investigate the effect of geometric dimensions (width and height) of a ground-shielded wire-type dual electrode on the current to a nearby metallic plate. The experimental results of this work clearly show that the current intensity generated by the corona electrode is higher using a narrower shield width. Otherwise, as long as the lower limits of the shield exceed the horizontal axis of the ionizing wire, the shield height does not affect significantly the current intensity produced by the discharge. These experimental results are validated by a series of corona-charging tests of insulating granules in the belt-type electrostatic separator. The quantities of particles recovered in the electro-separator are higher in presence of the shield, with well-chosen dimensions producing the highest possible corona current. These results may help to formulate some recommendations concerning the design of this type of electrode configuration. As the shield increases the output current of the electrode and broadens the ionized field, the proposed arrangement may be very useful for various industrial electrostatic processes

Neutralisation of electrically-charged insulating granular materials

International audienceDuring certain electrostatic process, diverse insulating granular materials acquire large amounts of charge, and retain it longer than necessary. The aim of this work was to model and optimize the elimination of the residual static charge of such materials. The triboelectric charging was assured by a propeller-type device. The neutralisation was carried out using a commercial-type air-assisted ionizer, located at various distances above a conveyor belt that transported the charged particles. The charge of the particles was measured before and after neutralisation using a Faraday cage. Neutralisation rates close to 100% could be achieved under optimal conditions

Distinct recovery of copper and aluminum from waste electric wires using a roll-type electrostatic separator

International audienceElectrostatic separators are commonly employed for the sorting of insulating and conducting fractions of granular mixtures. However, separation of the various metals that compose the conductive fraction still represents a major challenge for the recycling industry. The aim of this paper is to identify the conditions in which a roll-type electrostatic separator could be used for distinctly recover the copper and aluminum from waste electric wires. A numerical model of particle trajectories was employed to predefine these conditions and guide the experimental study. The electrostatic separation experiments were carried out using a reverse-S-type-plate high-voltage electrode. The visualization of particle trajectories using a high-speed camera paved the way to an original design. Thus, a metallic trap was attached to the high-voltage electrode, to facilitate the collection of the aluminum flake-like particles from a mixture that also contains copper strands. With a plastic trap replacing the metallic one, to avoid electric field modification, 68.6% of the copper was recovered with a purity attaining 99%

Multivariate Statistical Process Control of Electrostatic Separation Processes

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CALCULATION OF MAGNETIC FIELD FROM TRANSMISSION LINES WITH APPLICATION FOR FUTURE 400 KV ALGERIAN NETWORK

When designing of electric line, it is necessary to dimension these installations according to the high magnetic fields. This present paper gives a method to calculate and represent the magnetic field around a three-phase line; it proposes to bring to the originator and to the owner of these works the answers elements to problems raised by this constraint i.e. the determination of the intensities of magnetic fields to knowing their calculation and their measurement.  Certain spirits also worried about a possible physiological action of the magnetic fields; to appreciate such a possibility, it should be retained that the amplitude of the fields produced by the works of transport of energy is, on the surface of ground about (1 to 10 μTesla), i.e. of the same order of magnitude as the earth’s magnetic field, in other words it is the periodic character, at industrial frequency, which differentiates it from the natural earth’s field.  We present a calculation programme based on the MATLAB which makes it possible to better analyze and to represent the transverse profile of the magnetic field under the lines. We also give examples of application of the method and program particularly applied for future 400kv Algerian network

THE GROUND RESISTIVITY AND MEASUREMENT FREQUENCY INFLUENCES ON THE RADIONOISE DISTURBANCES LEVEL NEAR THE LINES HIGH VOLTAGE.

The principal objective of this paper is to present a determination calculation programme of the exact profile of the level of radio noise of existing lines V.H.V. and on a project, initially according to the resistivity of a ground and in the second phase according to the frequency.The method used for the determination of the disturbing field is an analytical method based on the theory of the modal propagation.We present a calculation programme based on MATLAB with examples of real lines. The principal objective of this paper is to present a determination calculation programme of the exact profile of the level of radio noise of existing lines V.H.V. and on a project, initially according to the resistivity of a ground and in the second phase according to the frequency.The method used for the determination of the disturbing field is an analytical method based on the theory of the modal propagation.We present a calculation programme based on MATLAB with examples of real lines