Chemical Recycling of Mixed Plastic Waste …...Institute for Technical Chemistry (ITC) Department Pyrolysis / Gas Treatment 2 09.10.2019 Chemical Recycling of Mixed Plastic WasteFeedstock

Institute for Technical Chemistry (ITC)Department Pyrolysis / Gas Treatment

1 09.10.2019 Chemical Recycling of Mixed Plastic Waste Feedstock with Screw Pyrolysis TechnologyHans Leibold et al.

KIT – The Research University in the Helmholtz Association

Institute for Technical Chemistry

www.kit.edu

Chemical Recycling of Mixed Plastic Waste Feedstockwith Screw Pyrolysis Technology

Hans Leibold, Marco Tomasi Morgano, Frank Richter

Chicago, ILOctober 9th 2019



Plastic waste in Germany 2017

Source: Stoffstrombild Kunststoffe in Deutschland 2017

Total

Post-Consumer

Post-Producer



Pyrolysis of plastic materials

Decomposition Gas

Vapors

Condensates

SolidsDegradation

Melting Decomposition

Shrinkage Melting

Pretreated

Plastic

Waste

Materials



STYX Pyrolysis reactor

Integrated Pyrolysis Reactor

Feedstock I

Pyrolysis Condensates

Pyrolysis vapors

PyrolysisGas

Condensation

N2

Electrical heating

Solids

Additives,Sorbents, Catalysts

N2

321

Filter elements

Reactor temperature < 500 °CResidence time solids < 60 minMass flow rate feedstock < 5 kg/hReactor length heated 2000 mmScrew Ø 150 mmHot vapor filtration 6 filterIn-situ sorption solid sorbents



Feedstock investigated

Polyethylen/Polypropylen mixture PE/PP

Post-consumer mixed plastic waste (model) MPW

Acrylnitrile-Butadien-Polyamide ABS

Polycarbonate

Polyamide

Sorting residue SR



Pretreatment of feedstock

00%

20%

40%

60%

80%

100%

120%

0 50 100 150 200 250 300

Temperature in °C

EPS#2EPS#3

0%

20%

40%

60%

80%

100%

120%

0 50 100 150 200 250 300 350 400Temperature in °C

PP#1PP#3

0%20%40%60%80%

100%120%140%160%

0 50 100 150 200 250 300 350 400Temperature in °C

PE#2PE#3

E-Polystyrene

Polyethylene Polypropylene

Hot stage microscope data

Swelling of specimen at the meltingpoint

Structure breakdown far above themelting point

Breakdown depends on plastic type



Pyrolysis PE/PP Mass Balance

0

5000

10000

15000

20000

25000

30000

35000

Mas

s [g

]

Input

Output

TREACTOR = 500°C

tR-PLASTICS = 30 min

ṁPLASTICS = 1 kg/h

tFEED = 5 h



Analysis of the PE/PP pyrolysis products

Valuable olefine fraction in the pyrolysis gas

Hydrocarbons < C21 in wax/ condensate product by GC

Staged condensation of hydrocarbons can be optimized

0.00.20.40.60.81.01.21.4

Con

cent

ratio

n [m

g/m

l]

PE-C1C2-0,8/3,2/30minPE-C3ESP-0,8/3,2/30min

05

10152025303540

Mas

s [%

]

PE-PP / 50-501,0/4,2/30min

Condensate

Pyrolysis gas



MPW - Post-consumer plastic wasteMass and carbon partitioning

Products: Condensate, permanent gas, solids – no wax

Condensate contains about 1.0 wt.% water from sorption reactions

Most of the aromatics are converted into coke HCl removal from vapors > 99.0 %

→ Cl- 343 mg/kg in condensate→ HCl 225 mg/m3 in pyrolysis gas (N2–free)

0

10

20

30

40

50

60

Solids Liquids Waxes Gas Loss

Yiel

ds [m

ass

%] Mass

Carbon

MPW + Ca(OH)2

T = 500°CτS = 30 min

ṁS = 0.8 kg/h



ABS - Mixed plastic waste Mass and carbon partitioning

Condensate > 66 wt.% on total input basis

Carbon loss due to larger hydrocarbons in gas + very low concentration in solids

Concentration Cl- in condensate < 150 mg/kg

Qualitative analysis of pollutants in gas indicates presence of HCl, HBr and HCN

01020304050607080

Solids Liquids Waxes Gas Loss

Yiel

ds [m

ass

%]

MassCarbon

ABS + Ca(OH)2

T = 500°CτS = 30 min

ṁS = 0.9 kg/h

Polycarbonate

Acrylonitrile butadiene styrene

Polyamide



MPW and ABS Plastic waste Gas analysis

Heating values similar to natural gas and superior to biogas

Chemicals recovery from the permanent gas: (ethylene and propylene)

Not all the species are quantitatively measured (C5+) → additional recovery of chemicals

Removal of trace components such as HCN from ABS and halogens HCl and HBrfrom PVC and from flame retardants in scrubber

MPW LHV: 42.2 MJ/kg

ABS LHV: 24.8 MJ/kg



ABS CondensateGC-MS and refining tests

Content Unit

Alkane < 5 wt.%

Alkene 10 wt.%

Cycloalkane < 1 wt.%

Aromatics 30 wt.%

Naphthalenes < 5 wt.%

Phenols 50 wt.%

Nitriles 5 wt.%

Others < 1 wt.%Hydrocarbons Phenols Others

Refining Technology Gasification+



SR – Sorting residueCatalytic upgrading

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Plastics Condensate Gas Residue Loss

thermalCatalyst ACatalyst BCatalyst C

Liquids Solids

Mass Balance

Steam Cracking



PyrolysisCore process of plastic circular economy

Mixed plastic waste

Pyrolysis

Refining Technology

Steam Cracking

Fluid Catalytic Cracking

Entrained Flow Gasification

Chemicals

Olefins

Gasoline

Syngas

Gas

Solids



Ecological balance pyrolysisSubstitution primary energy Base 1 t model mixture post-consumer plastic waste

Thinkstep 2018-45,000

-40,000

-35,000

-30,000

-25,000

-20,000

-15,000

-10,000

-5,000

0-41.798 -20.908 -20.399 -40.148 -26.329

ARCUS BestCase

ARCUS StandAlone

ARCUS WorstCase

MechanicalRecycling Incineration

Prim

ary

ener

gy [M

J]

Best Case Stand alone Worst CasePlastics Pyrolysis



Summary and outlook

Pyrolysis of mixed plastic waste materials with different thermal properties.

Particle-free liquid and gaseous products for chemical recycling ofplastic waste.

Pretreatment and adapted pyrolysis process are mandatory.

Selective removal of chlorine by dry in-situ sorption with alkali/earthalkali compounds.

Catalytic pyrolysis enables advanced pyrolysis products.

Ecological evaluation with mechanical recycling and combustionreveals the potential of plastics pyrolysis.

Refining of products according to FCC and steam cracker requirements.



Post-consumer mixed plastic waste - MPW

Plastics 2013 Plastic wastetotal

Plastic wastePost-Consumer

Plastic wastePost-Industrial

kt

Modelmixture

kt % kt % Producer Processor %PE-LD/LLD 1446 25,5 1310 27,6 11 125 30,0PE-HD/MD 750 13,2 631 13,3 6 110 15,0PP 955 16,8 797 16,8 13 145 15,0PS 290 5,1 263 5,5 2 25 10,0PS-E 117 2,1 91 1,9 3 23 0,0PVC 647 11,4 520 11,0 13 114 10,0ABS, ASA, SAN 98 1,7 74 1,6 1 23 10,0PMMA 32 0,6 26 0,5 1 5 0,0PA 84 1,5 59 1,2 4 21 0,0PET 568 10,0 520 11,0 3 45 10,0Misc. Thermoplastics 129 2,3 89 1,9 6 34 0,0PUR 243 4,3 182 3,8 6 55 0,0Misc. Plastics 320 5,6 185 3,9 2 133 0,0Total 5679 100,0 4747 100,0 74 858 100,0

Source: Analyse/Beschreibung der derzeitigen Situation der stofflichen und energetischen Verwertung von Kunststoffabfällen in DeutschlandConsultic Marketing & Industrieberatung GmbH für ITAD, April 2015

PE PP PS PVC ABS PET



Ecological balance pyrolysisCO2 foot print Base 1 t model mixture post-consumer plastic waste

140

1391 1380

-177

1376

-400

-200

0

200

400

600

800

1000

1200

1400

1600

ARCUS BestCase

ARCUS StandAlone

ARCUS WorstCase

MechanicalRecycling

Incineration

kg C

O2

eq.

Best Case

Plastics Pyrolysis

Thinkstep 2018

Stand alone Worst Case

Documents

Chemical Recycling of Mixed Plastic Waste …...Institute for Technical Chemistry (ITC) Department Pyrolysis / Gas Treatment 2 09.10.2019 Chemical Recycling of Mixed Plastic WasteFeedstock