Catalytic conversion of model compounds of plastic pyrolysis oil over ZSM-5

• Published in: Applied catalysis. B, Environmental Environmental, 2023-05, Vol.324, p.122219, Article 122219
• Main Authors: Dong, Son, Li, Houqian, Bloede, Iris K., Al Abdulghani, Abdullah J., Lebrón-Rodríguez, Edgard A., Huber, George W., Hermans, Ive
• Format: Article
• Language: English
• Subjects: Catalytic cracking; Plastic; Pyrolysis; Zeolite; ZSM-5
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2022.122219

Mechanistic investigation of the catalytic conversion of model compounds for plastic pyrolysis oil (1-octene, octadiene, octane, and toluene) over ZSM-5 in a fixed-bed reactor was studied. 1-Octene breaks down into smaller olefins, which undergo further cracking, oligomerization, cyclization, and hydrogen transfer to eventually produce benzene, toluene, xylene (BTX), coke, and hydrogen. The effect of contact time on 1-octene conversion was further investigated and compared with thermodynamics analyses to elucidate the reaction network. Under the reaction conditions (500 °C, 1 atm), octadiene undergoes thermal coking, significantly contributing to reactor fouling. The products from octane cracking are similar to the products from 1-octene conversion whereas toluene undergoes disproportionation, dealkylation and coking. The analysis of spent catalyst showed long-chain hydrocarbons created by oligomerization reactions filled the pores and covered the surface of the catalyst. When mesoporous ZSM-5 is used instead of conventional, product selectivity is maintained for 70 h in time-on-stream experiments. [Display omitted] •Contact time can be used as a handle to choose olefin-rich or aromatic-rich product.•Octadiene leads to thermal coking, significantly contributing to reactor fouling.•Spent catalyst contains long-chain hydrocarbons created by oligomerization.•Mesoporous ZSM-5 maintains its product selectivity for 70 h.