The effects of contact time and coking on the catalytic fast pyrolysis of cellulose

• Published in: Green chemistry : an international journal and green chemistry resource : GC Vol. 19; no. 1; pp. 286 - 297
• Main Authors: Yang, Haiping, Coolman, Robert, Karanjkar, Pranav, Wang, Haoyi, Dornath, Paul, Chen, Hanping, Fan, Wei, Conner, William Curtis, Mountziaris, T J, Huber, George
• Format: Journal Article
• Language: English
• Published: 2017
• Subjects: Catalysis; Catalysts; Cellulose; Coke; Coking; Contact; Deactivation; Pyrolysis
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/c6gc02239a

The effects of catalyst contact time (WHSV-1) and coking on catalytic fast pyrolysis of cellulose with ZSM-5 were studied in a bubbling fluidized bed reactor. Because coke interferes with catalyst activity, the effect of catalyst contact time was studied at coke loadings known not to deactivate the catalyst. CO and CH4 are favored at low catalyst contact times (<1000 s), oxygenated and unidentified species at medium catalyst contact times (1000 s-10 000 s), and aromatics and CO2 at high catalyst contact times (>10 000 s). At increased time on stream, the catalyst lost activity due to coking. The majority aromatic-producing activity was lost after site turnovers of 95 (cellulose monomers to Broensted sites) corresponding to a weight turnover of 2.0 (feed weight to catalyst weight). Accumulated coke deactivates the catalyst by both filling the micropores and blocking the acid sites.