Process simulation and life cycle assessment of waste plastics: a comparison of pyrolysis and hydrocracking

Muhammad Usman Azam, Akshay Vete, Waheed Afzal* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)
6 Downloads (Pure)


Pyrolysis and hydrocracking of plastic waste can produce valuable products with manageable effects on the environment as compared to landfilling and incineration. This research focused on the process simulation and life cycle assessment of the pyrolysis and hydrocracking of high-density polyethylene. Aspen Plus was used as the simulator and Peng-Robinson thermodynamic model was employed as a fluid package. Also, the sensitivity analysis was done to optimize product distribution. Based on the simulation, the hydrocracking process produced values added fuels i.e., gasoline and natural gas. In contrast, pyrolysis generated a significant quantity of pyrolysis oil with a high amount of cyclo-compounds and char which are the least important to be utilized as fuels. Moreover, in the later part of the study, life cycle assessment (LCA) was adopted to investigate and quantify their impact on the environment using simulation inventory data, which facilitates finding a sustainable process. Simapro was used as a tool for LCA of the processes and materials used. The results demonstrate that hydrocracking is a better process in terms of environmental impact in 10 out of the 11 impact categories. Overall, the present study proposed a promising comparison based on the energy demands, product distribution and potential environmental impacts which will help to improve plastic waste management.
Original languageEnglish
Article number8084
Number of pages35
Issue number22
Early online date21 Nov 2022
Publication statusPublished - 21 Nov 2022

Bibliographical note

Acknowledgements: This study was funded by The LEVERHULME TRUST (Grant DS-017-0723). Muhammad Usman Azam, a Leverhulme Trust Doctoral Scholar, is part of the 15 PhD scholarships of the “Leverhulme Centre for Doctoral Training in Sustainable Production of Chemicals and Materials” at the University of Aberdeen (Scotland, United Kingdom).


  • process simulation
  • waste plastics
  • pyrolysis
  • hydrocracking
  • life cycle assessment


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