Gasification and Pyrolyssis of plastic Waste under a Circular Economy perpective

Review on Gasification LCA. Presentation given by Cecilia Hofmann at Advanced Recycling Conference in Cologne, 2023.

1. Cecilia Hofmann [email protected]
T [phone]

2. Introduction
Environmental
Engineering
General
Engineering
Focus on economics
Research
internship
Consulting
internship
2020-2025 2022-20242020-2022 2023

3. Gasification and Pyrolysis of Plastic Waste under a
Circular Economy Perspective: a literature review
Pyrolysis
30%
Gasification
26%
Both
20%
No
specifity
24%
THEMES
7
19
31
21
0
10
20
30
40
1995-19992000-20092010-20192020-2023
STUDIES OVER THE
YEARSThe objectives of this work consist of a
bibliographic comparison of pyrolysis and
gasification methods for the recycling of
plastic waste into high-value
petrochemicals under a circular economy
focus.
More than 85 studies analysed
The report seeks to offer insights for policymakers, researchers,
and industries striving to develop sustainable plastic waste
management strategies.

4. Pyrolysis
Low temperature gasification
Syngas
Gasification
80%
54%
5%
32%
0%
50%
100%
PP, PE, PSPET
PRODUCT YIELD
LiquidSolid
Pyrolysis Oil
2260
172660
1000
2000
3000
GasSteelAshes
PRODUCT YIELD
Kg/tAnoxic process
Chemical IndistryEnergy SectorWaste-to-Product
Partial oxidation
Pyrolysis of plastic waste is a thermal decomposition process that occurs
in several stages and is typically conducted at elevated temperatures,
depending on the type of plastic and desired output. The output includes
solid residues (char), vaporized gas and pyrolysis liquid.
Gasification of plastic waste is an under-stoichiometric process that converts the
carbonaceous material in plastics into syngas in a controlled environment with a limited
supply of oxygen or steam. This syngas is composed mainly of hydrogen (H2) and
carbon monoxide (CO), along with smaller amounts of methane (CH4) and other gases.

5. Circular Economy
0
2
4
6
8
10
12
14
20062008201020122014201620182020
POST CONSUMER PLASTIC
WASTE TREATMENT
LandfillEnergy RecoveryRecycling
The goal is to transform plastics waste into new
resources, thereby reducing reliance on fossil-
based feedstocks and advancing the principles of
sustainability
“
”
Designing out waste and pollutionKeeping products and materials in useRegenerating natural systems

6. Comparison Criteria
Mass Balance
Energy Efficiency
Carbon Footprint
Mass balance refers to the accounting of inputs and outputs of a process to
ensure that all materials are properly accounted for, and no losses or gains
occur during the transformation.
Analyzing energy efficiency is key to enhancing recycling technologies for
a more sustainable approach. It guides improvements and comparisons
between chemical recycling methods, fostering a circular and resource-
efficient management of plastic waste.
In evaluating the feasibility of pyrolysis for chemical recycling of
plastic waste, the most commonly discussed criteria in literature include
product yields, energy efficiency, feedstock flexibility, environmental
impact, product quality and scalability.
Vital for the Circular Economy Transition, carbon footprint analysis
minimizes waste and boosts resource efficiency, meeting environmental
regulations and sustainability standards.
Explanning the criterias
Transform plastic waste into new resources
Reduce reliance on fossil-based feedstocks
Advance the principals of sustainability

7. Results and Conclusions
Uponcomparingpyrolysisandgasificationandthoroughlyexamining
variousaspects,ithasbeendeterminedthatrecyclingthrough
gasificationistheoptimalroutefortheaimsofthisproject.
Mass Balance
•Theuseofpyrolysisoilasafeedstockfornaphthacrackers,whichareemployedtoproduceolefinsandsubsequentlypolyolefins,hasposedsignificantchallenges.
Energy Efficiency
•Gasificationasaself-sufficientprocess,asitcanutilizetheheatgeneratedduringtheprocesstodrivethereactions
Carbon Footprint
•Gasificationshowedlowercarbonfootprintcomparedtopyrolysis,asconsequenceofitsrequirementforinputenergy

8. Results and Conclusions
Uponcomparingpyrolysisandgasificationandthoroughlyexamining
variousaspects,ithasbeendeterminedthatrecyclingthroughgasification
istheoptimalroutefortheaimsofthisproject.
Mass
Balance
•The use of pyrolysis oil as a
feedstock for naphtha crackers,
which are employed to produce
olefins and subsequently
polyolefins, has posed significant
challenges.
Mass balance analysis
Steam cracking
Reforming pyrolysis
Re-polymerization
Pyrolysis
products

9. Results and Conclusions
Uponcomparingpyrolysisandgasificationandthoroughlyexamining
variousaspects,ithasbeendeterminedthatrecyclingthroughgasification
istheoptimalroutefortheaimsofthisproject.
+713 kWh/t
-1337 kWh/t
Average of energy efficiency over the studies
Pyrolysis
GasificationEnergy
Efficiency
•Gasification as a self-sufficient
process, as it can utilize the heat
generated during the process to
drive the reactions

10. Results and Conclusions
1730
2558
1700
400
650580
0
500
1000
1500
2000
2500
3000
Kg of CO2/ tonne of plasteic treated
Xayachak, T.…Azamet al.…Perugini et…Khoo(2019)Cossuet al.…Chen etal…
Carbon Emition over the studies
Carbon
Footprint
•Gasification showed lower carbon
footprint compared to pyrolysis, as
consequence of its requirement for
input energy
Uponcomparingpyrolysisandgasificationandthoroughlyexamining
variousaspects,ithasbeendeterminedthatrecyclingthroughgasification
istheoptimalroutefortheaimsofthisproject.
Pyrolysis
Gasification

11. Final thoughts and Acknowledgments
Future work suggestions
•Heterogeneos Catalyts and co-
gasification
•Life Cycle Analysis (LCA)
•Cost-effectivenes and ScalabilityFlavio OrtigãoProf. Valdir Schalch