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Record 1 of 23
Thagard, SM; Mihalcioiu, A; Takashima, K; Mizuno, A. 2009. Analysis of the By-Products in the Ammonia Production From Urea by Dielectric Barrier Discharge. IEEE TRANSACTIONS ON PLASMA SCIENCE 37 (3):444-448, .
Times Cited 0
Abstract Ammonia, which is the main product of urea decomposition, is used as the reducing agent in the gas phase plasma NOx treatment. Urea, because of its cheap price and relatively low decomposition temperature (150 degrees C), represents an excellent direct source of ammonia. In a dielectric barrier discharge (DBD), such temperatures can be achieved within a few minutes of applying voltage. This paper deals with the chemical analysis of the by-products formed by urea decomposition at about 150 degrees C-200 degrees C in a DBD, since it is well known that, depending on the temperature, urea decomposition by-products can be quite different. It was found that 0.25 g of urea used can be completely decomposed in several minutes at a constant input applied voltage of 9 kV (10 kHz). The main by-products are ammonia, isocyanic acid, and cyanuric acid. Moreover, it was found that dry and humid air showed no difference in the by-products formed.
ISSN 0093-3813
DOI 10.1109/TPS.2008.2011132

Record 2 of 23
Medles, K; Senouci, K; Tilmatine, A; Bendaoud, A; Mihalcioiu, A; Dascalescu, L. 2009. Capability Evaluation and Statistical Control of Electrostatic Separation Processes. IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS 45 (3):1086-1094, .
Conference Title 40th Annual Meeting of the IEEE-Industry-Applications-Society
Conference Date OCT 02-06, 2005
Conference Location Hong Kong, PEOPLES R CHINA
Times Cited 0
Abstract The variability of the outcome is often deplored by the users of electrostatic separation equipment. A slight modification of the composition of the processed material, a change in the environmental conditions, or an alteration of the electrode configuration may cause objectionable fluctuation of product quality. Thus, the purity of the copper product recovered from electric cable wastes can easily diminish from 98%, which is fully acceptable for recycling purposes, to a value below the standard level of 97%. This paper is written with the aim of showing how statistical process control methods could contribute to the improvement of users' overall satisfaction. In order to validate a procedure for evaluating the short- and long-term capabilities of the electrostatic separation process, the authors carried out a series of experiments on subgroups of chopped electric cable wastes, which are similar to those currently processed in the recycling industry (95% polyvinyl chloride; 5% copper). The first set of experimental data showed that an "in-control" electrostatic separation process can easily satisfy the level of performance required by the customers (i.e., a capability index of > 1.33). The same set of data enabled the computation of the upper and lower limits of the R- and X-bar control charts. The second set of experiments was designed to evaluate the ability of these charts to detect the following typical situations of abnormal operation of the electrostatic separation equipment: 1) a change in the composition of the processed material; 2) a failed connection of the static electrode to the high-voltage supply; and 3) the accumulation of dust on the surface of the coroina electrode. Based on the authors' experience as consultants for the recycling industry, the following several recommendations have been formulated: 1) Evaluate the capability of the electrostatic separation process by performing no more than ten observations and making use of the confidence indexes; 2) use moving R- and X-bar control charts to obviate the difficulty of sampling; and 3) prepare a "Corrective Actions Guide" for the operators using control charts for monitoring.
ISSN 0093-9994
DOI 10.1109/TIA.2009.2018903

Record 3 of 23
Mihalcioiu, A; Takashima, K; Mizuno, A; Ohno, M; Ozawa, Y. 2009. Electrostatic Regeneration of Refrigerant. IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 16 (3):635-640, .
Times Cited 0
Abstract The ubiquity of air conditioning and cooling systems, the ban on refrigerant release to the environment, and the high energy required by the refrigerant decomposition process give good opportunity for a novel technology to deliver a "like new" recycled refrigerant. In this paper we present several electrostatic processes at the heart of this technology: tribocharging the recovered mix of oil and refrigerant; the oil is removed by an electrostatic filter; a Faraday ring sensor monitors filter efficiency. A portable system prototype incorporating these technologies was built..
ISSN 1070-9878

Record 4 of 23
Das, S; Medles, K; Mihalcioiu, A; Beleca, R; Dragan, C; Dascalescu, LGreen, N. 2009. Factors that Influence the Tribocharging of Pulverulent Materials in Compressed-air Devices - art. no. 012077. ELECTROSTATICS 2007 142 12077-12077.
Conference Title Electrostatics 2007 Conference
Conference Date MAR 25-29, 2007
Conference Location St Catherines Coll, Oxford, ENGLAND
Times Cited 0
Abstract Tribocharging of pulverulent materials in compressed-air devices is a typical multifactorial process. This paper aims at demonstrating the interest of using the design of experiments methodology in association with virtual instrumentation for quantifying the effects of various process varaibles and of their interactions, as a prerequisite for the development of new tribocharging devices for industrial applications. The study is focused on the tribocharging of PVC powders in compressed-air devices similar to those employed in electrostatic painting. A classical 2(3) full-factorial design (3 factors at two levels) was employed for conducting the experiments. The response function was the charge/mass ratio of the material collected in a modified Faraday cage, at the exit of the tribocharging device. The charge/mass ratio was found to increase with the injection pressure and the vortex pressure in the tribocharging device, and to decrease with the increasing of the feed rate. In the present study an in-house design of experiments software was employed for statistical analysis of experimental data and validation of the experimental model.
ISSN 1742-6588

Record 5 of 23
Dascalescu, L; Medles, K; Das, S; Younes, M; Caliap, L; Mihalcioiu, A. 2008. Using design of experiments and virtual instrumentation to evaluate the tribocharging of pulverulent materials in compressed-air devices. IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS 44 (1):3-8, .
Conference Title Joint Conference of the Electrostatics-Society-of-America/IEEE-Industrial-Applications-Society/Institute-of-Electrostatics-Japan/Societe-Francaise-of-Electrostatique
Conference Date JUN 06-09, 2006
Conference Location Berkeley, CA
Times Cited 2
Abstract Tribocharging of pulverulent materials in compressed-air devices is a typical multifactorial process. Quantification of the effects of the factors and of their interactions is a prerequisite for the development of new tribocharging devices for industrial applications. This paper aims at demonstrating the interest of using the design of experiments methodology in association with virtual instrumentation for the study of such processes, in view of their modeling and optimization. A classical 2(3) full-factorial design followed by a composite design were employed for conducting experiments simulating the tribocharging conditions of starch powder. The response function was the charge/mass ratio of the material collected in a modified Faraday cage, at the exit of the tribocharging device, the factors under investigation being the injection pressure, the dillution pressure, and the vortex pressure. The charge measurements were performed using a digital electrometer connected to a personal computer equiped with a data acquisition system. The data were processed by a custom-designed LabView virtual instrument. By using appropriate design of experiments software, it was possible to estimate the effects of these factors and then derive the model of the process as a quadratic polynomial function.
ISSN 0093-9994
DOI 10.1109/TIA.2007.912801

Record 6 of 23
Dascalescu, L; Mihalcioiu, A; Stochita, A; Notingher, PV. 2008. Charge-decay characteristics of granular materials forming monolayers at the surface of grounded electrodes. IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS 44 (1):20-24, .
Conference Title 40th Annual Meeting of the IEEE-Industry-Applications-Society
Conference Date OCT 02-06, 2005
Conference Location Hong Kong, PEOPLES R CHINA
Times Cited 1
Abstract Laboratory studies and in-field observations have shown that the charge-decay characteristics of the granular materials at the surface of the grounded roll electrode significantly influence the outcome of the electrostatic separation process. This paper validates an indirect method of charge-decay characterization, based on the measurement of the electrical potential at the surface of a monolayer of granular insulating material. The study was performed on three materials-polyvinyl chloride, polyethylene, and rubber-extracted from chopped electric wire wastes. The granules (characteristic size in the range 1-4 mm) were disposed on the surface of a grounded plate electrode (layer area: 100 mm x 100 mm; electrode area: 200 mm x 200 mm). A wire-type corona electrode, energized from a dc high-voltage supply, was employed for charging the granules. The potential due to the charge at the surface of the granular layer was measured with the capacitive probe of an electrostatic voltmeter connected to a personal computer. Data acquisition and processing were done using the LabView environment. The influence of particles characteristics and of ambient factors was studied. The findings enabled a more accurate modeling of discharging phenomena that affect the performances of electrostatic separators. The method can be easily adopted in electrostatic discharge studies for material characterization.
ISSN 0093-9994
DOI 10.1109/TIA.2007.912803

Record 7 of 23
Calin, L; Mihalcioiu, A; Das, S; Neamtu, V; Dragan, C; Dascalescu, L; Iuga, A. 2008. Controlling particle trajectory in free-fall electrostatic separators. IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS 44 (4):1038-1044, .
Conference Title Joint Conference of the Electrostatics-Society-of-America/IEEE-Industrial-Applications-Society/Institute-of-Electrostatics-Japan/Societe-Francaise-of-Electrostatique
Conference Date JUN 06-09, 2006
Conference Location Berkeley, CA
Times Cited 0
Abstract The purity and recovery of concentrates obtained in industrial free-fall electrostatic, separators can be increased by preventing the impacts between the particles and the electrodes. The aim of this paper is to analyze the possibility to control particle trajectories in such separators by modifying the conditions of particle admission in the interelectrode space. The parametric equations of a charged particle trajectory in the electric field between the electrodes of a free-fall separator served for writing a numerical modeling program in MATLAB. The ten control factors of the. free-fall electrostatic separation process were employed as input variables of this program: particle charge and dimension, trajectory start point coordinates, feed input angle and initial velocity, electrode length and inclination, interelectrode spacing, and applied high voltage. A custom-designed laboratory free-fall electrostatic separator (length of the electrodes: 1000 mm; standard interelectrode spacing: 300, mm; and nominal high voltage: 90 kV), provided with a fluidized-bed tribocharger, was employed for validating the conclusions of the numerical modeling. The geometrical data of this separator were taken into account for computing the initial velocity nu(o) of the particles entering the electric field zone. Another important parameter of the numerical model, which is the granule charge q, was attributed the value measured at the exit of the fluidized-bed tribocharger. The numerical simulations were performed for the two values of the feed input angle: alpha = 4 degrees and alpha = 8 degrees, considering polyethylene therephtalate (PET) and polyvinyl chloride (PVC) particles of different sizes. A good agreement was found between the theoretical predictions and the results of the experiments carried out with two binary mixtures: 50% PET/50% PVC and 10% PET/90% PVC. Both the numerical modeling and the experimental study demonstrated that the feed input angle alpha influences the outcome of the electrostatic separation to a great extent.
ISSN 0093-9994
DOI 10.1109/TIA.2008.926690

Record 8 of 23
Calin, L; Mihalcioiu, A; Iuga, A; Dascalescu, L. 2007. Fluidized bed device for plastic granules triboelectrification. PARTICULATE SCIENCE AND TECHNOLOGY 25 (2):205-211, .
Times Cited 2
Abstract The study of the triboelectrification process is the key factor to the successful industrial application of electrostatic separation in the field of plastics recycling. Therefore, the aim of the present work is to evaluate an original device for the laboratory study of this process. The original design of the fluidized bed type triboelectrification device has the following distinctive features: (i) transparent walls to observe the fluidization process and the particles moving in the triboelectrification module; (ii) air distributors with different mesh apertures correlated with granule size; (iii) quick replacement of the triboelectrification Plexiglas chamber with other metallic ( aluminium, copper) or nonmetallic chambers ( polyvinyl chloride - PVC, polyethylene - PE, and polyethylene terephthalate - PET); (iv) possibility of independent operation, for granule charge measurement or integrated operation, for the electrostatic separation experiments using a free-fall electrostatic separator. The results of charge measurement experiments pointed out the different triboelectric behaviour of two types of granules ( polystyrene and low-density polyethylene) in contact with the walls of the device. The electrostatic separation experiments carried out on a binary mixture of mm-size polystyrene/polyethylene granules confirmed the effectiveness of the triboelectrification device.
ISSN 0272-6351
DOI 10.1080/02726350701257782

Record 9 of 23
Mihalcioiu, A; Neamtu, V; Stochita, A; Dascalescu, L. 2007. High-voltage monitoring in electrostatic separators. IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS 43 (1):224-231, .
Conference Title 39th Annual Meeting of the IEEE-Industry-Applications-Society
Conference Date OCT 03-07, 2004
Conference Location Seattle, WA
Times Cited 1
Abstract High voltage is known to be one of the main control variables in any electrostatic-separation process. From this perspective, the aim of this paper is twofold: to develop an effective high-voltage monitoring system and to demonstrate that it can be a useful tool for controlling the overall operating conditions of an electrostatic-separator system. A custom-designed virtual instrument was employed for processing the experimental data provided by a high-voltage probe, the output of which was connected to an electrometer. In several experiments, the output of the high-voltage probe was also connected to a digital oscilloscope, in order to obtain a better understanding of the variation of the electrode potential after a spark discharge. The laps of time without corona. discharge and/or with low electric field intensities could thus lie accurately determined, and the impact of the spark discharges on the outcome of the separation process evaluated. The dispersion of high-voltage measured values was found to increase in the presence of the material. The statistical analysis of the data revealed a significant correlation between the standard deviation of the high-voltage and the concentration of metal in the processed material. The results of this paper could be helpful for those seeking the optimization of the operating conditions for the electrostatic separation applications, in which the metal content in the feed materials exhibits substantial fluctuation with time.
ISSN 0093-9994
DOI 10.1109/TIA.2006.887315

Record 10 of 23
Yoshida, K; Mihalcioiu, A; Okubo, M; Kuroki, T; Yamamoto, T. 2007. NOx Aftertreatment System for Diesel Engine Emission Using Thermal Desorption and Plasma Reduction Combined Process. CONFERENCE RECORD OF THE 2007 IEEE INDUSTRY APPLICATIONS CONFERENCE FORTY-SECOND IAS ANNUAL MEETING, VOLS. 1-5 1871-1876.
Conference Title 42nd Annual Meeting of the IEEE-Industry-Applications-Society
Conference Date SEP 23-27, 2007
Conference Location New Orleans, LA
Times Cited 0
Abstract In our previous studies, a novel NOx aftertreatment system using adsorption and reduction by nonthermal plasma desorption is proposed. In the present study, application of the system to a real stationary diesel engine generator is investigated. The NOx is first removed by adsorption, then the adsorbent is regenerated by thermal desorption using waste heat of the exhaust gas. In the regeneration process, hot exhaust gas passes through the heat exchange tubes surrounded by the adsorbent pellets. The desorbed NOx is subsequently reduced to N-2 by nitrogen nonthermal plasma. This system reduces around 50% of 245 similar to 270 ppm NOx emitted by the generator for 8 hours.
ISSN 0197-2618

Record 11 of 23
Mihalcioiu, A; Yoshida, K; Okubo, M; Kuroki, T; Yamamoto, T. 2007. Design Factors for NOx Reduction in Nitrogen Plasma. CONFERENCE RECORD OF THE 2007 IEEE INDUSTRY APPLICATIONS CONFERENCE FORTY-SECOND IAS ANNUAL MEETING, VOLS. 1-5 1877-1880.
Conference Title 42nd Annual Meeting of the IEEE-Industry-Applications-Society
Conference Date SEP 23-27, 2007
Conference Location New Orleans, LA
Times Cited 0
Abstract The aim of this paper is to analyze the influence of plasma discharge reactor unit geometries on the efficiency of dry NO, reduction process in nitrogen plasma environments. The experimental setup consists of the versatile plasma discharge reactor unit powered by 10 kHz pulse HV supply and supplied by mass flow controllers with a simulated (NO+N-2) gas under different concentrations and flowing rates. The measurements are obtained by the means of a gas analyzer for NO/NOx concentration and a digital oscilloscope supplied with HV and current probes for discharge power computation. The number of surface discharge electrodes, the distance between them, their active area, the gas flow rate and concentration are studied while aiming at 30 g(NO2)/kWh energy efficiency and higher reduction efficiencies. These targets are keys to industrial application of plasma discharge reactor, as a way of reducing NO, from the regeneration phase, in the next generation diesel exhaust aftertreatment system and the results proved successful.
ISSN 0197-2618

Record 12 of 23
Dascalescu, L; Samuila, A; Mihalcioiu, A; Bente, S; Tilmatine, A. 2005. Robust design of electrostatic separation processes. IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS 41 (3):715-720, .
Conference Title ESA-IEEE/IAS/EPC Joint Meeting 2003
Conference Date JUN 24-27, 2003
Conference Location Little Rock, AR
Times Cited 9
Abstract The aim of this paper is to analyze the robustness of the electrostatic separation process control. The objective was to reduce variation in the process outcome by finding operating conditions (high-voltage level, roll speed), under which uncontrollable variation in the noise factors (granule size, composition of the material to be separated) has minimal impact on the quantity (and the quality) of the recovered products. The experiments were carried out on a laboratory roll-type electrostatic separator, provided with a corona electrode and a tubular electrode, both connected to a dc high-voltage supply. The samples of processed material were prepared from genuine chopped electric wire wastes (granule size > 1 mm and < 5 mm) containing various proportions of copper and PVC. The design and noise factors were combined into one single experimental design, based on Taguchi's approach, and a regression model of the process was fitted. The impact of the noise factors could be estimated, as well as the interactions between the design and noise factors. The conditions of industry application of Taguchi's methodology are discussed, as well as the possibility of adapting it to other electrostatic processes.
ISSN 0093-9994
DOI 10.1109/TIA.2005.847308

Record 13 of 23
Dascalescu, L; Mihalcioiu, A; Stochita, A; Notingher, P. 2005. Charge-decay characteristics of granular materials forming mono-layers at the surface of grounded electrodes. Conference Record of the 2005 IEEE Industry Applications Conference, Vols 1-4 1414-1417.
Conference Title 40th Annual Meeting of the IEEE-Industry-Applications-Society
Conference Date OCT 02-06, 2005
Conference Location Hong Kong, PEOPLES R CHINA
Times Cited 0
Abstract Laboratory studies and in-field observations shown that the charge decay characteristics of the granular materials at the surface of the grounded roll electrode significantly influence the outcome of the electrostatic separation process. The present paper validates an indirect method of charge decay characterization, based on the measurement of the electrical potential at the surface of a monolayer of granular insulating material. The study was performed on three materials - PVC, PE and rubber - extracted from chopped electric wire wastes. The granules (characteristic size in the range 1 to 4 mm) were disposed on the surface of a grounded plate electrode (layer area: 100 mm x 100 mm; electrode area: 200 mm x 200 mm). A wire-type corona electrode, energized from a DC high-voltage supply, was employed for charging the granules. The potential due to the charge at the surface of the granular layer was measured with the capacitive probe of an electrostatic voltmeter connected to a personal computer. Data acquisition and processing were done using the LabView environment. The influence of particles characteristics and of ambient factors was studied. The findings enabled a more accurate modelling of discharging phenomena that affect the performances of electrostatic separators. The method can be easily adopted in ESD studies for material characterisation.
ISSN 0197-2618

Record 14 of 23
Iuga, A; Calin, L; Neamtu, V; Mihalcioiu, A; Dascalescu, L. 2005. Tribocharging of plastics granulates in a fluidized bed device. JOURNAL OF ELECTROSTATICS 63 (6-10):937-942, .
Conference Title 10th International Conference on Electrostatics
Conference Date JUN 15-17, 2005
Conference Location Espoo, FINLAND
Times Cited 12
Abstract The paper presents a modular fluidized bed device for the study of plastics tribocharging and electrostatic separation, with application in the field of plastic recycling. Evaluation of the device in independent operation for charge-to-mass ratio measurements pointed out the different triboelectric behaviour of six tribocharging chambers made of plastic (PVC, PP, PET, PE, PMMA) and aluminium. The electrostatic separation tests carried out on PET and PVC granulates confirmed the effectiveness of the fluidized bed tribocharging device integrated in a free fall separator. They pointed out three charging mechanisms by particle/particle and particle/walls collisions. (c) 2005 Elsevier B.V. All rights reserved.
ISSN 0304-3886
DOI 10.1016/j.elstat.2005.03.064

Record 15 of 23
Medles, K; Tilmatine, A; Bendaoud, A; Senouci, K; Das, S; Mihalcioiu, A; Dascalescu, L. 2005. Capability evaluation and statistic control of electrostatic separation processes. Conference Record of the 2005 IEEE Industry Applications Conference, Vols 1-4 2590-2596.
Conference Title 40th Annual Meeting of the IEEE-Industry-Applications-Society
Conference Date OCT 02-06, 2005
Conference Location Hong Kong, PEOPLES R CHINA
Times Cited 0
Abstract The variability of the outcome is often deplored by the users of electrostatic separation equipment. This paper is written with the aim of showing how statistical process control methods could contribute to the improvement of users' overall satisfaction. In order to validate a procedure for evaluating the short and long term capability of the electrostatic separation process, the authors carried out a series of experiments on subgroups of chopped electric cable wastes, similar to those currently processed in the recycling industry. The first set of experimental data enabled the computation of the upper and lower limits of two types of control charts. The second set of experiments was designed to evaluate the ability of these charts to detect typical situations of abnormal operation of the electrostatic separation equipment. Several recommendations have been formulated based on authors experience as consultants for the recycling industry.
ISSN 0197-2618

Record 16 of 23
Mihalcioiu, A; Dascalescu, L; Das, S; Medles, K; Munteanu, R. 2005. Virtual instrument for statistic control of powder tribo-charging processes. JOURNAL OF ELECTROSTATICS 63 (6-10):565-570, .
Conference Title 10th International Conference on Electrostatics
Conference Date JUN 15-17, 2005
Conference Location Espoo, FINLAND
Times Cited 6
Abstract The paper demonstrates that statistic process control (SPC) techniques could be of great use for monitoring the tribo-charging of pulverulent materials in compressed-air transportation systems or in electrostatic deposition devices. A virtual instrument was developed using LabView (c) in order to process the data acquired by an electrometer connected to a modified Faraday pail. By sampling the charge of the powder collected in the pail, it was possible to build up SPC charts that appropriately reflect the tribo-charging phenomena related to the processing of finely divided materials. (c) 2005 Elsevier B.V. All rights reserved.
ISSN 0304-3886
DOI 10.1016/j.elstat.2005.03.017

Record 17 of 23
Dascalescu, L; Mihalcioiu, A; Tilmatine, A; Mihailescu, M; Iuga, A; Samuila, A. 2004. Electrostatic separation processes - A linear-interaction optimization model using Taguchi's experimental design technique.. IEEE INDUSTRY APPLICATIONS MAGAZINE 10 (6):19-25, .
Times Cited 2
ISSN 1077-2618

Record 18 of 23
Dascalescu, L; Mihalcioiu, A; Tilmatine, A; Medles, K; Samuila, A. 2004. Effect of ambient humidity on the outcome of electrostatic separation processes. CONFERENCE RECORD OF THE 2004 IEEE INDUSTRY APPLICATIONS CONFERENCE, VOLS 1-4 1947-1953, .
Conference Title 39th Annual Meeting of the IEEE-Industry-Applications-Society
Conference Date OCT 03-07, 2004
Conference Location Seattle, WA
Times Cited 1
Abstract Taguchi's methodology has already been applied to the robust design of an electrostatic separation processes the outcome of which was affected by two hard-to-control "noise factors": granule size and composition of the materials to be selectively sorted. The aim of the present work was to expand that investigation to an additional "noise factor": the relative humidity of ambient air. The objective was to reduce variation in the process outcome by finding operating conditions (high-voltage level, roll speed, splitter position), under which uncontrollable variation in "noise factors" (ambient humidity, copper content in the feed) has minimal impact on the quantity (mass of middling fraction) and the quality (purity of the copper fraction) of the recovered products. The experiments were carried out on a laboratory roll-type electrostatic separator. The samples of processed material were prepared from genuine chopped electric wire wastes (granule size > 1 mm and < 2 mm) containing various proportions of copper (5%, 25%, and 45%) and PVC. The ambient relative humidity varied between 40 and 60%, at a temperature of 20 +/- 1degreesC. The design and noise factors were first analyzed using a classical Taguchi approach, then combined into one single experimental design, so that a regression model of. the process be fitted. Several additional experiments at lower (30%) or higher (70%) relative humidity have been performed, to asses the feasibility of electrostatic separation in less standard environmental conditions. The conditions of industry application of Taguchi's methodology are discussed.
ISSN 0197-2618

Record 19 of 23
Mihalcioiu, A; Neamtu, V; Stochita, A; Dascalescu, L. 2004. High-voltage monitoring in electrostatic separators. CONFERENCE RECORD OF THE 2004 IEEE INDUSTRY APPLICATIONS CONFERENCE, VOLS 1-41974-1980, .
Conference Title 39th Annual Meeting of the IEEE-Industry-Applications-Society
Conference Date OCT 03-07, 2004
Conference Location Seattle, WA
Times Cited 0
Abstract High voltage is known to be one of the main control variables of any electrostatic separation process. From this perspective, the aim of the present work is double: develop an effective high-voltage monitoring system, and demonstrate that it can be an useful tool for supervising the overall operating conditions of electrostatic separators. A custom-designed virtual instrument was employed for processing the experimental data provided by a high-voltage probe the outpot of which was connected to an electrometer. In several experiments, the output of the high-voltage probe was also connected to a digital oscilloscope, in order to obtain a better characterisation of the variation of the electrode potential after a spark discharge. The laps of time without corona discharge and/or with low electric field intensities could thus be rather accurately determined, and the impact of spark discharges on the outcome of the separation process evaluated. The dispersion of high-voltage measured values was found to increase in the presence of the material. The statistical analysis of the data revealed a significant correlation between the standard deviation of the high-voltage and the concentration of metal in the processed material. These findings could be helpful for the optimisation of the operating conditions of the electrostatic separation applications where the metal content in the feed materials is characterized by important fluctuations with time.
ISSN 0197-2618

Record 20 of 23
Samuila, A; Mihalcioiu, A; Urs, A; Dascalescu, LMorgan, H. 2004. Unipolar charging and contact discharging of insulating particles on the surface of a grounded electrode. ELECTROSTATICS 2003 (178):65-69, .
Conference Title 11th International Conference on Electrostatics
Conference Date MAR 23-27, 2003
Conference Location Heriot Watt Univ, Edinburgh, SCOTLAND
Times Cited 0
Abstract The study of the unipolar charging of insulating particles has been stimulated by the recent development of several important electrostatic technologies: precipitation of dusts, deposition of powders, separation of granular materials. The aim of the present work is to analyse the discharging conditions of insulating disks in contact with an electrode, after having been charged in a unipolar corona field. The experiments were carried out on a roll-type electrostatic separator that simulated the charging/discharging conditions in an industrial unit. The measured data show that the discharge process is a complex phenomenon, depending of at least the following factors: the conductivities of the respective bodies, the aspect of the contact, and the environmental conditions.
ISSN 0951-3248

Record 21 of 23
Urs, A; Samuila, A; Mihalcioiu, A; Dascalescu, L. 2004. Charging and discharging of insulating particles on the surface of a grounded electrode. IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS 40 (2):437-441, .
Conference Title Annual Meeting of the Industry-Applications-Society
Conference Date OCT 13-18, 2002
Conference Location PITTSBURGH, PA
Times Cited 3
Abstract The aim of the present paper is to analyze the corona. charging of millimeter-size insulating disks, as well as their discharging when they are no longer exposed to the action of an external electric field. The experiments were carried out on a roll-type electrostatic laboratory separator, equipped with a wire-type corona electrode, simulating the actual charging/discharging conditions in an industrial unit. Disks of various sizes were charged on the surface of the roll electrode, then the high voltage supplied to the corona electrode was turned off and the particles Were collected in a Faraday pail, connected to an electrometer. The charge measurements were performed at various time intervals from high-voltage turn-off. In this way, the charge decay could be recorded and the discharge process fully characterized. The measured data show that the discharge process depends on the nature, size, and shape of the particles, as well as on the contact conditions between the particles and the grounded roll electrode. These data could guide the design of the electrostatic separation experiments that precede any new industrial application of this technology.
ISSN 0093-9994
DOI 10.1109/TIA.2004.824500

Record 22 of 23
Dascalescu, L; Mihalcioiu, A; Tilmatine, A; Mihailescu, M; Iuga, A; Samuila, A. 2002. A linear-interaction model for electrostatic separation processes. CONFERENCE RECORD OF THE 2002 IEEE INDUSTRY APPLICATIONS CONFERENCE, VOLS 1-4 1412-1417, .
Conference Title 37th Annual Meeting of the Industry-Applications-Society
Conference Date OCT 12-18, 2002
Conference Location PITTSBURGH, PA
Times Cited 0
Abstract Previous studies based on Box-Wilson and response surface methods have proven that the design of experiments is a powerful tool in improving electrostatic separation performances by controlling the two main parameters of the process: the high-voltage level and the roll speed. The aim of the present paper is to analyze the possibility of deriving a mathematical model capable to reflect the effects of a larger number of factors, as well as their main interactions. At first, the main variables of the process were listed and classified in accordance with the ease of controlling them. Then two experimental designs were chosen, in accordance with Taguchi's methodology. The objective was to minintize the middling fraction. The experiments were carried out on a laboratory roll-type electrostatic separator, provided with a corona electrode and a tubular electrode, both connected to a d.c. high-voltage supply. The samples of processed material were prepared from genuine chopped electric wire wastes (granule size > 1 mm and < 2 mm) containing 25% copper and 75% PVC. The first experiment consisted of 16 tests, which enabled the derivation of a linear-interaction model comprising 7 variables and 8 interactions. The second experiment consisted of only 8 tests, as the corresponding model took into consideration 4 variables and 3 interactions. A good agreement was obtained between the two models.
ISSN 0197-2618

Record 23 of 23
Urs, A; Samuila, A; Mihalcioiu, A; Dascalescu, L. 2002. Charging and discharging of insulating particles on the surface of a grounded electrode. CONFERENCE RECORD OF THE 2002 IEEE INDUSTRY APPLICATIONS CONFERENCE, VOLS 1-4 990-994, .
Conference Title 37th Annual Meeting of the Industry-Applications-Society
Conference Date OCT 12-18, 2002
Conference Location PITTSBURGH, PA
Times Cited 1
Abstract The study of the ionic charging of insulating particles is intimately related to the technological developments in the field of electrostatic precipitation of dusts, deposition of powders, or separation of granular materials. The aim of the present paper is to analyze the corona charging of mm-size insulating disks, as well as their discharging when they are no longer exposed to the action of an external electric field. The experiments were carried out on a roll-type electrostatic laboratory separator, provided with a wire-type corona electrode, simulating the actual charging/discharging conditions in an industrial unit.. Particles of various sizes were charged on the surface of the roll electrode, then the high voltage supplied to the corona electrode was turned off and the particles collected in a Faraday pail, connected to an electrometer. The charge measurements were performed at various time intervals from high-voltage turn-off. In this way, the charge decay could be recorded and the discharge process fully characterized. The measured data show that the discharge process depends on the nature, size and shape of the particles, as well as on the contact conditions between the particles and the grounded roll electrode. These data could guide the design of the electrostatic separation experiments that proceed any new industrial application of this technology.
ISSN 0197-2618


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