Plastic Recycling Technology

Plastics Recycling

Sophea BeoutMaster’s Degree,

Mining and Petroleum Engineering,Faculty of Engineering,

Chulalongkork University

Mineral Resource Recycling Technology

November, 2015

Outline Previous Research

I. Introduction

II. Types of Plastic and application

III.Life Cycle of Plastic

IV.Plastic Recycling

- Recycling Process

- Plastic Recycling Technique

V. Conclusion

VI. Reference

Previous research of Plastic Processing

• Somsak, S., 2014, Separation of PVC from PET/PVC Mixture using flotation by Calcium Lignosulfonate Derpressant: Separation PVC from mixture of PET/PVC with different ratios of PET and PVC by using CaLS as

the depressant.• Gjergj, D., et al., 2006, Sorting Techniques for Plastics Recycling:

Three methods involving in separation ABS, PS and PP from mixture of PVC/PP, ABS/PS and PET/PE. The three methods used were Air Table for separation PVC from mixed PVC/PP. The second method was Triboelectric cyclone separator to remove ABS from mixed ABS/PS. The last method was sink-Float and froth flotation in separation PET from mixture of PET/PE.

• Gjergj, D., et al., 2003, Triboelectrostatic Separation of ABS, PS and PP Plastic Mixture: Using Triboelectrostatic to separate ABS, PS and PP plastic from mixture of ABS/PS/PP by

applying DC power to electrode up to ± 20 kV thus to produce electric field of 400kV/m.• Malcolm, R., et al., Enhanced Plastics Recycling by Cyclone Media Separation:

The separation focusing on different density of plastics types. The media separators used are Cylindrical and DMS cyclones as shown in APPENDIX D.

• Plastics-The Fact, 2010, 2011, 2012 and 2013: An analysis of European plastics production, demand and recovery.

Introduction

• Plastic is the general common term for a wide range of synthetic or semi-synthetic materials used in a huge, and growing, range of applications.

• The demand of plastics is increased every year; growth rate is 5-6% every year

• In 2015, the demand will reach 297.5 Mtonnes; and reach until 400 Mtonne in 2020 (GIA, 2014; Paddos, 1999).

• The main production countries: China, Japan, European and other countries

What is plastic?

Plastic-The Fact, 2010, 20111, 2012, 2013

Plastic-The Fact, 2013

Introduction

Different uses of plastic, (%)

What is plastic?


Types of Plastic and Application

• 7 types of Plastics• SPI have coded each type of plastic by number from 1 until 7• Every kind of Plastic can be recycled according to their

component and give different recycled products



Different type of Plastic with different needs


Life Cycle of Plastic—Water Bottle

• Water bottle– Mainly made from PET• The Life Cycle of Water Bottle:

Raw materials extractionManufacturing Production processProduct distribution and UsageEnd-of life

Reuse (some plastic can be reuse in appropriate of time) Recycle Landfill Energy recovery





In Europe, 2012

Plastic Recycling

Categories Number Recycled Product

Easiest 1-PET Fiberfil for coats, sleeping bed

2-HDPE Toys, piping

Less commonly 3-PVC Baby bottle nipples

4-LDPE Wrapping films, grocery, sandwich gabs

5-PP (not so acceptable for recycling)

Useful 6-PS Meat tray, packing peanuts…

Hardest 7-Others Most difficult to recycle

Categories for recycling

Plastic RecyclingRecycled Product

PET

PVCHDPE

Recycling Process

• Collection/Sellection• Separation• Processing

– Manual Sorting– Free of contamination

Plastic Recycling

Recycling ProcessPlastic Recycling

Plastic recycling, 2014 (http://biophysics.sbg.ac.at/waste/plastic.htm)

Recycling Process--VideoPlastic Recycling

Recycling Process--Extruder:Plastic Recycling

– The melting equipment of plastic– Melting system: Shear heating system

Recycling Process –Extruder videoPlastic Recycling

Recycling Techniques Plastic Recycling

• The purpose is to separate different kinds of plastic homogenously from mixture of plastic and other wastes

• Several techniques applied in recycling plastic: – Sink-float separation technique, – Electrostatic separation, – A dry separation technique that utilizes the

electrical charging of particles

Recycling Techniques –case examplesPlastic Recycling

• Separation of ABS,PVC and PP from mixture of PVC/PP, ABS/PS and PET/PE within 50%/50%– PVC/PP => Air Table– ABS/PS => Triboelectric cyclone separator– PET/PE => Combination of Sink-Float Separation

and Froth Flotation

Recycling Techniques – ABS, PS, PP separation processPlastic Recycling


Air Table:- Density of PVC = 1.4 g/ml; and PP = 0.9 g/ml- Velocity of airflow: 1.6m/s-Frequency of deck: 11.95/s-End slope α=4.4°; side slope β=2.5°-Sample size:2.38– 3.36 mm

PVC, high density => settle on the bed

PP, low density => Float on the top of the bed


Triboelectric cyclone separator• Separate ABS from ABS/PS• DC power supply• Based on the different charge of Plastic types• ABS goes to negative part, PS goes to Positive Part


Triboelectric cyclone separator


Sink-float and flotation:-PET’s density = 1.35 g/ml, PE’s density = 0.96 g/ml, lower than water’s.-Reagent Dodecylamine (DAA) = 0.02 kg/m3, for PE to float out and Pet is sink as hydrophilic stage. -Sample size: from 2.38– 3.36 mm, is the size after shredders

Recycling Techniques – ABS, PS, PP separation ResultPlastic Recycling

Types PVC from PVC/PP

ABS from ABS/PS PET from PET/PE

Method Air Table Triboelectric cyclone separator

Sink-float and Flotation

Recovery 97.1% PP; 99.5% PVC

100%PS; 74% ABS

90.3% PET

Grade 99.3% PP; 99.3% PVC

---- 99.7% PET

Result:

Recycling Techniques – Separation of PVC from PET/PVCPlastic Recycling

Method use: Flotation• Three mixture of samples are experimented• Ratio PET/PVC: 75:25, 50:50, 25:75• Depressant CaLS = 7.5 mg/l• pH ; 11-12• Time : 20 mn• Pipe oil : Frother agent, 10 drops• Size shape: 5x5 mm and thickness 0.3 mm.• Temperature = 60°C


Process of experiment:

- PET : sink- PVC : Float

Somsak, 2014


• Result Ratio of PET/PVC

%weight PET

CaLS (mg/l)

RecoveryPVC PET

75:25 74 7.5

100 100 (after 4th of Rougher)

50:50 48 7.5

100 100 (after 2th of Rougher)

25:75 24 7.5

100 100.(after 3th of Rougher)

Saving term-- Do you Know…?Plastic Recycling

Recycling plastic is making the balance of environmental, energy, and economic saving.

4% of natural oil, which is estimated about 2 million barrels of oil every day used to produce Plastic every year (The ImpEE, 2005; Recycling Fact, 2012)

Recycle Plastics need only 10% of total energy compared to production of plastic from virgin sources (Recycling Fact, 2012)

Saving term-- Do you Know…?Plastic Recycling

Comparison the energy use and resources price of virgin and recycled materials

Commodity

plastic

Energy, virgin

materials (MJ/kg)Price, virgin

materials ($/kg)

Energy, recycled

materials (MJ/kg)Price, recycled

materials ($/kg)

HDPE 77-85 1.9-2.0 ≈35-45 0.84-0.97

PP 75-83 1.8-1.85 ≈35-45 0.99-1.1

PET 79-88 2.0-2.1 ≈60-64 1.1-1.2

PS 96-105 1.5-1.6 ≈40-50 0.75-0.86

PVC 63-70 1.4-1.5 ≈35-40 0.77-0.99

(The ImpEE, 2005; Recycling Fact, 2012)

Conclusion

Plastic is widely used all around the world for everyday life, construction, automobile, electronic and other things to make life more modernity and convention, but in the same time, it cause environmental problem such as global greenhouse gases emission (methane gas).

Recycling Plastic is not only saving the petrochemical sources, but also saving the energy.

Some recycling technique such as air separation, density, electrical, sink-float and flotation are suitable with acceptable efficient of recovery, according to the previous researches.

Conclusion

Plastics are too valuable to through away!Each piece of plastics waste is money!Landfill plastic must be eliminated since it takes

hundreds of years to discompose and causes contamination to the surrounding communities.

Please, think a little bit that…

ConclusionPlease, think a little bit that…

References

[1] Somsak, S., 2014, Separation of PVC from PET/PVC Mixture using flotation by Calcium Lignosulfonate Depressant, Chulalongkorn University, Bankok, Thailand[2] Gjergj, D., et al., 2003, Triboelectrostatic Separation of ABS, PS and PP Plastic Mixture, University of Oviedo, Oviedo, Spain[3] Gjergj, D., et al., 2006, Sorting Techniques for Plastics Recycling, , University of Oviedo, Oviedo, Spain[3] Malcolm, R., et al., Enhanced Plastics Recycling by Cyclone Media Separation, University of Oviedo, Oviedo, Spain[4] Plastic-The Fact, 2010, 2011, 2012, 2013, An analysis of European latest plastics production, demand and waste data[5] Plastic recycling, 2014, (online), (www.biophysics.sbg.ac.at/waste/plastic)[6] The ImpEE Project, 2005, Recycling of Plastic, University of Cambridge. [7]Plastic Waste Management Institute, 2009, An Introduction to Plastic Recycling.

http://www.biophysics.sbg.ac.at/waste/plastic

http://www.biophysics.sbg.ac.at/waste/plastic

?