Lucien ELECTROSTATIC PROCESSES AND ENVIRONMENTAL PROTECTION DASCALESCU IEEE Fellow Distinguished Professor University of Poitiers FRANCE 1 APPLICATIONS OF HIGH-INTENSITY ELECTRIC FIELDS ELECTROSTATIC PROCESSES AND Industrial waste recycling Water treatment ENVIRONMENTAL PROTECTION Gas purification 2 Electrostatic processes OUTLINE Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration 3 APPLICATIONS OF ELECTROSTATIC PROCESSES Photocopying Air ionisation Electrostatic processes Applications to industrial waste recycling Water treatment Electrostatic separation of WEEE Water treatment Air filtration Separation ESD MEMS (Lab-on-a-chip) Micro-fluidics Cell manipulation EHD Gas filtration Spraying and Devices atomisation Environmental protection Biotechnologies Medicine 4 PARTICLE TRAJECTORIES Coulomb’s force : F = Q E Centrifugal force : Fc = m R w2 Weight : Fg = mg Electrostatic processes Applications to industrial waste recycling Vibratory feeder Rotating electrode Electrostatic Brush separation of WEEE Water treatment Air filtration Non-conducting particles Corona electrode Electrostatic electrode Conducting particles Collector Electric image force : Fi = Q2/[4p o (2r)2] 5 CORONA CHARGING OF GRANULAR MATERIALS HV Supply Electrostatic processes Applications to industrial waste recycling Corona electrode Grounded electrode Faraday’s cage Electrostatic separation of WEEE Water treatment Air filtration Electrometer 6 CORONA DISCHARGE Electrostatic processes Dual-type electrodes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration Distribution of corona current density 7 INDUSTRIAL WASTES Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration Grinding Micronisation Electrostatic sorting 8 CHOPPED ELECTRIC CABLES Electrostatic processes Applications to industrial waste recycling PVC Cu Electrostatic separation of WEEE Water treatment Air filtration 9 ELECTRIC CABLE PODS Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration 10 ELECTROSTATIC SEPARATION: A MULTIFACTORIAL PROCESS Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Corona electrode (high-voltage level) Vibratory feeder (feed rate, granule size) Electrostatic electrode (size, shape, positioning) Grounded roll-electrode (roll speed) Brush NC M C Splitter (splitter angle) Water treatment Air filtration 11 PROCESS OPTIMISATION EXPERIMENTAL DESIGN METHODOLOGY A D Voltage U a Electrostatic processes f s1 [mm] B U E [kV] e 34 50 F Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration 40 Electrode position C b d O H c s1, a1 G 30 30 40 α1 [°] Optimal operation point U = 34 kV 12 INDUSTRIAL ELECTROSTATIC SEPARATOR RECYCLING OF METALS AND PLASTICS FROM WASTES Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration HAMOS KWS 4 roll-electrodes, length: 1.500 mm fully automatic 3 shift operation throughput up to 1000 kg/h 13 WEEE = Waste Electric and Electronic Equipment Electrostatic processes Applications to industrial waste recycling “WEEE Man‖ Hight: 7 m Weight: 3,3 t Electrostatic separation of WEEE Water treatment Air filtration 14 PLASTICS IN WEEE : 30% Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration 2006: 109 PC in the world 15 1st Problem : REMOVAL OF METAL PARTICLES Electrostatic processes AlAl Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration Cu Cu 16 2 solutions : Electrostatic separators Electrostatic processes Roll-type Applications to industrial waste recycling Electrostatic separation of WEEE Plate-type Water treatment Air filtration 17 2nd Problem : SEPARATION OF MIXED GRANULAR PLASTICS Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration 18 1st solution : Roll-type corona-electrostatic separator Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration Dual type corona electrode R ++++ ++ + Corona discharge zone ac Fi NC a Q F e Non-conductive particles Grounded rotating roll electrode Fc Fg C Conductive particles 19 1st solution : Roll-type corona-electrostatic separator Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration Dual corona electrode Electrostatic Voltmeter TREK 370 U=19,5 kV Potential probe Granules 2 mm s 70 mm 20 mm Potential decay at the surface of a layer of granular material 20 1st solution : Roll-type corona-electrostatic separator Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration 3.5 [kV] surface potential Potentail Surface [kV] Electrostatic processes 3.0 PE S2 (PE) 2.5 2.0 1.5 Rubber 1.0 S3 (rubber) 0.5 0.0 0 1 2 3 4 5 6 7 8 time [s] Time [s] 21 1st solution : Roll-type corona-electrostatic separation Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration R =128 mm, 3 RPM, APPLICATION: Séparation PE/ caoutchouc PE [%] Rubber [%] Total [%] Feed 50 50 100 NC Product 75 29 52 C Product 25 71 48 22 INDUSTRIAL PVC/RUBBER SEPARATOR Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration 23 2nd solution : Tribo-electrostatic separator Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration 24 2nd solution : Tribo-electrostatic separator Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration PET concentrate obtained by electrostatic separation of the 90% PET & 10% PVC mixture 25 2nd solution : Tribo-electrostatic separator Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration Vibratory Tribocharging Device; 1: tribocharging tubes; 2: opening for the evacuation of the charged particles; 3: slider; 4: base plate; 5: tube-carrying plate; 6: eccentric wheel; 7: driving electric motor 26 2nd solution : Tribo-electrostatic separator Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration 1: HV supply 75kV; 2: electrodes; 3: separation chamber 4: Vibratory Tribocharging Device; 5: LV supply; 6: frequency meter; 7: control panel; 8: HV supply 50 kV; 27 9: collecting boxes. 2nd solution : Tribo-electrostatic separator Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment PET and PVC concentrates obtained by triboelectrostatic separation 28 3rd problem : SEPARATION OF PULVERULENT PLASTICS Electrostatic processes Compressed air Tribo-gun « SAMES » Faraday’s cage Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Electrometer 29 OZONE GENERATORS Electrostatic processes Applications to industrial waste recycling Dielectric barrier discharge Electrostatic separation of WEEE (Siemens) Water treatment Air filtration 30 DIRECT OZONIZATION OF LIQUIDS Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration Multi-point corona discharge device 1—AC high-voltage supply, 25 kV, 5 mA, 50 Hz; 2—Petri vessel; 3—active electrode; 4—treated liquid; 5—metallic contact between treated liquid and grounded electrode; 6—grounded electrode 31 OZONE GENERATION FOR WATER TREATMENT Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration I – Grounded liquid II – Liquid at floating potential 32 ELECTROSTATIC PRECIPITATORS Principle of operation Electrostatic processes F=QE Particle migration velocity v Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration Increase E et Q, by reducing D Reducing D => increase v => reduce Q 33 NEW MODELS OF ELECTROSTATIC PRECIPITATORS Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration (i) Better particle charging by intensifying the corona discharge in zone I (ii) Better particle collection by reducing the speed of the zone II 34 EXPERIMENTAL MODELS MODEL 1 (“classic”) Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration L = 198 mm D1 = 40 mm MODEL 2 (“modified”) L1 = 50 mm L2 = 15 mm D1 = 40 mm D2 = 30 mm 35 COLLECTION EFFICIENCY RESULTS ―classic‖ vs. ―modified‖ Model 2 (modified) Model 1 (classic) η [%] η [%] U = 0 kV, p = 1.7 bar 16,8 11,2 Electrostatic separation of WEEE U = 0 kV, p = 2.5 bar 11,1 7,2 U = 10 kV, p = 1.7 bar 98,8 96,8 Water treatment U = 10 kV, p = 2.5 bar 95,8 94,4 Electrostatic processes Applications to industrial waste recycling Air filtration Experimental conditions 36 CAR AIR FILTERS Increase the efficiency Electrostatic processes Applications to industrial waste recycling Electrostatic separation of WEEE Water treatment Air filtration Corona charging of non-woven filters 37 CHARGE AND DISCHARGE OF AIR FILTERS Electrostatic processes Applications to industrial waste recycling Surface potential decay measurement Conveyor Corona charge Sample Electrostatic separation of WEEE Water treatment Air filtration 38 SURFACE POTENTIAL DECAY High voltage 18 kV Electrostatic processes Electrostatic separation of WEEE Water treatment 20 mm 1.4 11 12 14 16 18 1.2 Surface potential (kV) Applications to industrial waste recycling 20 mm 1 kV kV kV kV kV 0.8 0.6 0.4 0.2 0 0 100 200 300 Time [s] 400 500 600 Time (sec) Air filtration 39 APPLICATIONS OF HIGH-INTENSITY ELECTRIC FIELDS ELECTROSTATIC PROCESSES AND ENVIRONMENTAL PROTECTION Perspectives of scientific co-operation Projet SAKURA - New micro-plasma devices for air/water treatment applications - improving the air filtration technologies 40 Doumoarigatou 41
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