1. RECYCLYING AND RECOVERY ROUTES OF
PLASTIC SOLID WASTE(PSW)
PRESENTED BY, GUIDED BY,
SHAHAN P P Ms. SITHARA S
H7652 Assistant Professor
1

2. CONTENTS
 Scope
 Introduction
 PSW treatment options
 Re-extrusion
 Mechanical recycling
 Chemical recycling
 Energy recovery
 Thermolysis
 Pyrolysis
 Gasification
 Hydrogenation 2

3. SCOPE
SOLUTION TO THE MOUNTINGS
PROBLEM OF PLASTIC SOLID WASTE.
 EXPLORE RECYCLING AND RECOVERY
ROUTES.
3

4. INTRODUCTION
 Plastics are light-weight, durable, and versatile
 Disposal has become a major worldwide environmental
problem.
 Non Biodegradable
 New sustainable processes have emerged
 Account for the use of 4% - 8% of the global oil
production
 The most appropriate recovery method is chosen
considering the environmental, economic and social
impact of a particular technique.
4

5. 5

6. RE-EXTRUTION
 Re-introduction of scrap, industrial or single-polymer
plastic edges.
 Only feasible with semi-clean scrap.
 Rarely possess the required quality.
 Main source are households.
 Need of selective and segregated collection.
6

7. MECHANICAL RECYCLING
 PSW are recycled into “new” raw materials
 No change in the basic structure of the material.
 Performed on single- polymer, eg.PE,PP,PS etc
 Grocery bags, pipes, window & door profiles etc
 Costly and an energy intense process.
 Involves lot of steps.
 First step is size reduction to pellets,powder or flakes.
7

8. MECHANICAL RECYCLYING STEPS
8

9. THERMO-CHEMICAL RECYCLING
 Advanced technology.
 Convert into smaller molecules, usually liquids or
gases suitable for use as a feedstock for the
production of new petrochemicals and plastics.
 De- polymerisation.
 High product yield and minimun residual waste
 Chemical recycling
Method of producing various hydrocarbon
fractions from PSW.
1. pyrolysis,
2. Gasification
3. catalytic degradation
9

10. THERMOLYSIS
 Treatment of PSW in the presence of heat at controlled
temperatures and environment.
 Divided into,
1. Pyrolysis
2. Gasification
3. Hydrogenation
Pyrolysis
• Thermal degradation of plastics in the absence of
oxygen.
10

11.  Applied to PET , PS , PMMA and certain polyamides
such as nylon.
 Advanced conversion technology that has the ability
to produce a clean, high calorific value gas.
 Hydrocarbon content of the waste is converted into a
gas, which is suitable for utilization in gas engines or
in boiler applications
 Calorific value of 22–30 MJ/m3
 Polyolefins:potential pyrolysis feedstock for fuel
(gasoline) production.
11

12. BASF PROCESS
 Main pyrolysis technologies ever commissioned.
 Mixed PSW is grinded, and separated from metals and
agglomerated materials.
 HCl separated out is absorbed and processed in the
HCl production plant.
12

13. GASIFICATION
 Partial oxidation of plastic waste.
 Operated at high temperatures (600°C- 800°C).
 Air or oxygen- gasification agent.
 Primary product : mixture of CO, H2 with minor
percentages of gaseous hydrocarbons.
 This mixture is syngas.
 Attractive alternative to direct incineration.
13

14. CONVENTIONAL TECHNOLOGIES?
14

15. Any material that contains carbon can be gasified.
Advantage of using air instead of O2 alone is to simplify the process and
to reduce the cost.
Disadvantage is N2 being present causing the reduction in the calorific value
of resulting syngas.
15

16. DISPOSAL METHODS
Burning
thermal
processing in the
absence of air or
oxygen
thermal
processing with a
limited amount of
air or oxygen
INCINERATION
PYROLYSIS
GASIFICATION
16

17. AUTOMOTIVE SHREDDER RESIDUE
 Aggregate that remains after a vehicle has been
shredded.
 Practical value as recyclables.
 Eg.plastics, rubber, fiber, glass, residual metal etc
 Recent devolopment involves the gasification of ASR.
17

18. TEXACO GASIFICATION PROCESS
 Consists of two parts,
 Liquefaction step
o Plastic waste is mildly thermally cracked.
o Synthetic heavy oil and some condensable and non-
condensable gas fractions.
o Non-condensable gases are reused in the liquefaction
as fuel
 Entrained bed gasifier
o Oil and condensed gas produced are injected to the
entrained gasifier.
o 1200°C - 1500°C.
o After cleaning processes ,clean and dry synthesis gas
formed consisting predominantly of CO and H2.
18

19. 19

20. HYDROGENATION
 Addition of hydrogen (H2) by chemical reaction
through unit operation.
 Veba Combi-Cracking- most robust, commercially
proven hydrogen addition technologies available in
the marketplace today.
 Process refinery residues, heavy crude oil and coal.
20

21. ENERGY RECOVERY
 Burning waste to produce energy in the form of heat,
steam and electricity.
 Sensible way of waste treatment, when material
recovery processes fail.
 Plastic materials possess a very high calorific value.
 High heating value of plastics make it a convenient
energy source.
 Producing H2O and CO2 upon combustion make them
similar to other petroleum based fuel. 21

22. CALORIFIC VALUE OF SOME MAJOR PLASTICS COMPARED
WITH COMMON FUELS…..
Item Calorific value (MJ kg−1)
Polyethylene 43.3–46.5
Polypropylene 46.50
Polystyrene 41.90
Kerosene 46.50
Gas oil 45.20
Heavy oil 42.50
Petroleum 42.3
Household PSW mixture 31.8
22

23. CONCLUSIONS
 Recycling technologies of PSW have contributed greatly to
the eco-image of waste management.
 Certain disadvantages appear when mechanical recycling
is chosen.
 Tertiary treatment of waste plastic articles is by far a more
sustainable solution.
 (PSW) is derived from oil and has a recoverable energy, in
some cases comparable to other energy sources.
 Many tertiary and quaternary technologies appear to be
robust to warrant further research and development in the
near future. 23

24. REFERENCES
 Gasification of plastic waste as waste-to-energy or waste-to-syngas
recovery route Vol.5, No.6, 695-704 (2013)
http://dx.doi.org/10.4236/ns.2013.56086
 Baeyens, J., Brems, A. and Dewil, R., (2010) Recovery and recycling of post-
consumer waste materials—Part 2. Target wastes (glass beverage bottles,
plastics, scrap metal and steel cans, end-of-life tyres, batteries and house-
hold hazardous waste). International Journal of Sustainable Engineering, 3,
232-245. doi:10.1080/19397038.2010.507885.
 Al-Salem, S.M., Lettieri, P. and Baeyens, J. Recycling and recovery routes of
plastic solid waste (PSW): A review. Waste Management, 29, 2625-2643.
doi:10.1016/j.wasman.2009.06.004
 Harder, M.K. and Forton, O.T. A critical review of developments in the
pyrolysis of automotive shredder residue. Journal of Analytical and Applied
Pyrolysis, 79, 387-394. doi:10.1016/j.jaap.2006.12.015.
24

25. THANK YOU…..
25