Tribo-Electrostatic Beneficiation of Recycled Polymers

Transcription

1 Tribo-Electrostatic Beneficiation of Recycled Polymers Review of Past Work and Discussion of an Improved Separation System Rodger Butler, Kyle Flynn ST Equipment & Technology, Needham MA

2 Motivation Dry Processing of Recycled Polymers (Recycled Carpet) for Beneficial Use Recovery of Nylon with Ash Content Less than 5% Removal of Calcium Carbonate Separation of Nylon from Polypropylene Others?

3 Outline Conventional Electrostatic Separation (ESS) Review of Previous Work using ESS for Polymers New Technology - STET Tribo-electrostatic Belt Separator Applications for The STET ESS

4 Conventional ESS Technology High Tension Roll (HTR) Separators Limitations Separates conductors from non-conductors (metal from plastic) All particles must contact drum surface Feed rates <5 TPH/m drum width Lower particle size limit: ~0.075 mm Elder and Yan, 2003

5 Conventional ESS Technology Free Fall Separators Physical footprint Limitations Single stage separation Must maintain laminar flow Avoid particle-to-particle contact in separation zone Large electrode gap High applied voltage Low particle loading Low throughput / capacity Elder and Yan, 2003 Particle Size Effects Too large No separation Too small Collects on Electrodes Motion influenced by aerodynamics Lower particle size limit of ~0.10 mm

6 Triboelectric Series for Plastics Triboelectric Series for Plastic Positive End + Acrylonitrile-Butadiene- Styrene ABS Polypropylene PP Polycarbonate PC Polyamide (Nylon) PA Polyethylene Terephthalate (Polyester) PET Polystyrene PS Polyethylene PE Polyvinyl Chloride PVC Polytetrafluoroethylene PTFE Negative End - The Triboelectric series differs slightly based on the researcher reporting the work. The STET Separator relies on particle-toparticle charging, and is able to separate materials with small differences in work function. 1. G. Dodbiba, Magnetic and Electrical Separation, Vol. 11, No. 1-2, pp Hersh, S.P., and Montgomery, D.J., Text. Res. J., Vol. 25, pp. 279

7 Summary of Past Work I.I. Inculet Inst. Phys. Conf., (1991) Used a fluidized bed tribo-charging device Separated Acrylic, Nylon, PE or PVC achieving 95% purity. G. Dodbiba Akita University, Japan ( ) Air cyclone particles charged by contact with cyclone Separated PET from PE with grade higher than 95% Separated ABS, PS and PP with grades of 85 92% C. Xiao American Plastics Council Rotating drum charging device with free fall separator Separation of PC from PVC

8 STET Electrostatic Separator

9 STET Electrostatic Separator Small gap and intense agitation High electric field strength with moderate applied voltage (typ kv) High efficiency multi-stage separation through charging/recharging & internal recycle Very low residence times Wide particle size range High capacity ~1 sec <0.001 to ~0.5 mm Up to 1,400 ft^3/hr

10 STET Electrostatic Separator Plant Location Country Separators Comission Date New England Power Somerset, MA Duke Energy Roxboro, NC CPSG Brandon Shores, MD Scottish Power Longannet, Scotland Jacksonville Electric SJRPP Jacksonville, FL SMEPA Morrow, MS NB Power Belledune, NB RWE Didcot, England PP&L Brunner Island, PA TECO Big Bend, FL RWE Aberthaw, Wales EDF Energy W. Burton, England ZGP Janikowo, Poland KOSEP YONG HEUNG 5 & Siekerki Poland

11 Consistent Product from Variable Feed

12 Recommended Applications Completely Liberated Material Ideally a Two Component Mixture Dry and Free Flowing Fine - 100% less than 500 microns

13 Thank You! Thank You! ST Equipment & Technology 101 Hampton Ave Needham, MA Rodger Butler Director Contract Administration (+1) Kyle Flynn Manager, Process Engineering (+1)

14 Backup Slides The Following Slides are Included as Supporting Material

15 STET Proven Results Calcium Carbonate Talc Barite Fly Ash 200,000 TPY 8 % - 25% LOI Feed 9.5% SiO 2 58% Talc 42% Magnesite 82%BaSO (SG) < 1% SiO 2 95% Talc 92% BaSO4 Processed ash: 77% Recovery 4.21 SG 2.5% LOI Results 89% CaCO 3 Recovery Improved Brightness 88% Talc 82% Recovery 74% Recovery

16 STET Electrostatic Separator Economic Value Annual Product Volume (thousand tons / year) NO Maybe YES 0 $0 $20 $40 $60 $80 $100 $120 $140 $160 $180 $200 $220 $240 $260 $280 $300 Value Created (USD per ton product)

17 STET Electrostatic Separator