Identification of the coke deposited on an HZSM-5 zeolite catalyst during the sequenced pyrolysis-cracking of HDPE

- Sequenced pyrolysis-cracking of HDPE using HZSM-5 zeolite yields 60 wt% of olefins.
- Catalyst is deactivated by coke; we report on pathways, equations and precursors.
- Waxes deposit on the mesopores of the catalyst and evolve towards condensed coke.
- Olefins form coke on the acid sites of the catalyst that plug the micropores.