tribo-electrostatic beneficiation of recycled polymers...annual product volume (thousand tons /...

Tribo-Electrostatic Beneficiation of Recycled

PolymersReview of Past Work and Discussion of an Improved

Separation System

Rodger Butler, Kyle FlynnST Equipment & Technology, Needham MA

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?

ST Equipment & Technology LLC, Confidential

Outline

Conventional Electrostatic Separation (ESS)

New Technology - STET Tribo-electrostatic Belt Separator

Applications for The STET ESS

2

3

4

1

Review of Previous Work using ESS for Polymers


Conventional ESS Technology – High Tension Roll (HTR) Separators

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

Limitations

Elder and Yan, 2003


Conventional ESS Technology – Free Fall Separators

Elder and Yan, 2003

Physical footprint

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

Too large – No separation

Too small – Collects on Electrodes

Motion influenced by aerodynamics

Lower particle size limit of ~0.10 mm

Particle Size Effects

Limitations


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 -

1. G. Dodbiba, Magnetic and Electrical Separation, Vol. 11, No. 1-2, pp. 63-92 2. Hersh, S.P., and Montgomery, D.J., Text. Res. J., Vol. 25, pp. 279

• The Triboelectric series differs slightly based on the researcher reporting the work.

• The STET Separator relies on particle-to-particle charging, and is able to separate materials with small differences in work function.


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 (2001 – 2003)• 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


STET Electrostatic Separator



Small gap and intense agitationHigh electric field strength with moderate applied voltage (typ. 8 - 20 kV)High efficiency multi-stage separation through charging/recharging & internal recycle

Very low residence times ~1 sec

Wide particle size range <0.001 to ~0.5 mm

High capacity Up to 1,400 ft^3/hr


STET Electrostatic SeparatorPlant Location Country Separators Comission

DateNew England Power Somerset, MA 1 1995

Duke Energy Roxboro, NC 2 1997

CPSG Brandon Shores, MD 2 1999

Scottish Power Longannet, Scotland 1 2002

Jacksonville Electric SJRPP Jacksonville, FL 2 2003

SMEPA Morrow, MS 1 2004

NB Power Belledune, NB 1 2005

RWE Didcot, England 1 2005

PP&L Brunner Island, PA 2 2007

TECO Big Bend, FL 3 2008

RWE Aberthaw, Wales 1 2008

EDF Energy W. Burton, England 1 2008

ZGP Janikowo, Poland 1 2011

KOSEP YONG HEUNG 5 & 6 1 2014

Siekerki Poland 1 2016


Consistent Product from Variable Feed


Recommended Applications

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


Thank You!

Thank You!ST Equipment & Technology

101 Hampton Ave

Needham, MA 02494

+1-781-972-2300 www.steqtech.com

Kyle FlynnManager, Process Engineering

(+1) [email protected]

Rodger ButlerDirector Contract Administration

(+1) [email protected]


http://www.steqtech.com/

Backup Slides

• The Following Slides are Included as Supporting Material


STET Proven ResultsFe

ed

Resu

lts

Calcium Carbonate

9.5% SiO2

< 1% SiO2

89% CaCO3Recovery

Improved Brightness

Talc

58% Talc

42% Magnesite

95% Talc

77% Recovery

88% Talc

82% Recovery

Barite Fly Ash

200,000 TPY

82%BaSO4

3.78 (SG)

8 % - 25% LOI

92% BaSO4

4.21 SG

74% Recovery

Processed ash:

2.5% LOI



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Value Created (USD per ton product)

Economic Value

YESMaybe

NO


tribo-electrostatic beneficiation of recycled polymers...annual product volume (thousand tons /...

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