Steam cracking of polypropylene for the production of light olefins in a fountain confined conical spouted bed reactor

This paper presents an alternative approach for plastic waste valorization in a fountain confined conical spouted bed reactor. The study evaluates the application of an upgraded spouted bed design for the steam cracking of polypropylene (PP) at 750 °C, focusing on high value added products. The highly efficient cracking process results in a high gas yield of 80.9 wt%. This stream is composed of H₂, CO, CO₂, C₁-C₄ paraffins and C₂-C₄ olefins, with the latter reaching a total yield of 49.2 wt%. Among the light olefins, propylene (21.8 wt%) and ethylene (16.5 wt%) are the most relevant. Interestingly, a remarkable yield of the valuable BTX fraction was obtained, 14.0 wt%, with benzene being the predominant compound. The reactor configuration and excellent control of process conditions enhanced light olefins yield by β-scission and radical mechanism, promoting the formation of light hydrocarbons, as well as minimizing secondary oligomerization and reforming reactions. This study is a proof of the viability of steam cracking in a fountain confined spouted bed reactor for converting PP into valuable chemical intermediates, as well as the viability of this technology for industrial application in waste plastic valorization.