Thermochemical recycling of complex polymers: General decomposition pathways for pyrolysis of end-of-life-tires

Typ
Examensarbete för masterexamen
Master's Thesis
Program
Sustainable energy systems (MPSES), MSc
Publicerad
2024
Författare
Sköld, Adam
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
With an increasing population of the world, our reliance on tires in transportation and production of goods is following suit. As tires are relying on fossil fuels to produce both synthetic rubbers and the filler carbon black, recycling the material in end-of-life tires (ELTs) and closing the carbon loop is of great importance for continuing the production of tires in a sustainable fashion. Thermochemical conversion using pyrolysis is a viable option and has been proven to be commercially viable as the company Scandinavian Enviro System has shown by using the recovered carbon black in new tires, and the oils as feedstock to the petrochemical industry. To be able to predict the results from pyrolysis of ELTs, understanding the process is a must. In this work, the behaviour of the solid and volatile products was investigated using prior experiments, literature review and followed by modelling, done using both an empirical model as well as a simplified reactor model (SRM) using kinetics based radical reactions. The empirical model investigated the feasibility of using key species, i.e. species providing significant information about the process to be used in an implicit fashion to decrease the complexity of both models and analysis in experiments. The solid behaviour indicates the significance of how the particle is heated, as this dictates how if the particle is swelling or shattering as the volatile compounds are leaving the material. The interaction between the solid and volatile vapours leaving the sample was investigate further in a literature review, where the influence of heating rate was shown to affect the amount of carbonisation in the solid yield, where lower heating rates favoured carbonisation. The heating rate was also shown to influence the secondary reactions as yields of aromatic content increase with heating rate at the expense of aliphatic content, along with slightly higher gas production. The empirical model took heating rate into account when predicting the carbon conversion to species in both the oil and gas using a key specie. The models showed the promise of utilizing key species, while the species chosen, ethylene and styrene, should be investigated further in future research. By increasing the complexity in the simplified reactor model, additional insight regarding radical rearrangement could be gleaned, however, significant focus should be put on the kinetic parameters of the different reactions to create a more holistic decomposition model.
Beskrivning
Ämne/nyckelord
Tire pyrolysis , ELTs , Carbon black , Pyrolysis , Aromatic hydrocarbons , Empirical modelling
Citation
Arkitekt (konstruktör)
Geografisk plats
Byggnad (typ)
Byggår
Modelltyp
Skala
Teknik / material
Index