Evaluation of continuous pyrolysis and in-line catalytic dry reforming of commodity plastics for syngas production

• Continuous pyrolysis dry reforming allows for plastics conversion into syngas. • Process performance is affected by the composition and reactivity of pyrolysis volatiles. • Catalyst space time determines the extent of conversion and the final syngas composition. • Polyolefins exhibited the highest hydrogen and syngas yields, and highest H 2 /CO ratios. The role played by plastic composition in the pyrolysis and in-line dry reforming process was analysed. A continuous unit combining a conical spouted bed reactor for plastics fast pyrolysis and a fluidized bed reactor for dry reforming was used. This study includes five different polymers, i.e., three polyolefins (HDPE, LDPE and PP), PS and PET. The pyrolysis step was carried out at 550 °C. The product stream composition obtained in the fast pyrolysis greatly varied depending on the polymer in the feed. Thus, these products were mainly olefins and paraffins in the pyrolysis of polyolefins, and aromatic hydrocarbons and oxygenates in the case of PS and PET, respectively. The dry reforming process was performed at 650 °C with a CO 2 /C molar ratio of 1.5 and space time values of 5 and 20 g cat min g volatiles -1 . The performance in the reforming of pyrolysis volatiles also differed depending on the polymer treated. Thus, polyolefins led to promising results in terms of syngas production and suitable H 2 /CO ratio. Furthermore, the pyrolysis stream derived from polyolefins proved to be more reactive. However, PS and, especially, PET showed a poorer performance in terms of syngas quality and yield, as well as their pyrolysis stream reactivity.