On-line deoxygenation of cellulose pyrolysis vapors in a staged autothermal reactor

Nils E. Persson, Samuel D. Blass, Corey Rosenthal, Aditya Bhan, Lanny D. Schmidt

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


We demonstrate the coupling of oxidative cellulose pyrolysis with zeolite-catalyzed upgrading of pyrolysis vapors in a staged autothermal reactor over bifunctional combinations of HZSM-5, HFER, or USY with Pt/γ-Al 2O3. The pyrolysis vapors formed from oxidative decomposition of cellulose passed through a downstream bifunctional zeolite stage to form a mixture of aromatics, C2-C4 olefins and paraffins, CO, CO2, and CH4. A comparison of the bifunctional staged reaction with that of monofunctional zeolite catalysts revealed a ∼13% increase in conversion of pyrolysis vapors to deoxygenated products. Of the pyrolysis vapor entering the zeolite catalyst, 24% was converted to aromatics while an additional 20% was converted to C 2-C4 olefins and paraffins. Complete conversion of cellulose to CO, CO2, light hydrocarbons and aromatics was obtained at 500 °C upon addition of Pt/γ-Al2O3 to HZSM-5. Deactivation of the catalysts reduced the conversion of pyrolysis vapors to deoxygenated products as indicated by an increase in the oxygenate yield with time-on-stream. Oxygenate yield measured after the zeolite stage increased to 6% after 30 minutes on stream over bifunctional HZSM-5/Pt, and increased from 13% to 31% at the same time-on-stream over monofunctional HZSM-5. Pt likely promoted hydrogenation of the coke precursors produced in the staged reactor while the 10-MR pore size of HZSM-5 limited the formation of polyaromatic species. A 6% increase in CO2 yield and 5% increase in CH4 yield was observed when Pt/γ-Al2O3 was added to each zeolite, indicating the possible presence of water-gas-shift and methanation reactions, respectively, over Pt sites. The small-scale high-throughput autothermal reactor that we describe here is capable of carrying out cellulose depolymerization and upgrading in a single-pipe process.

Original languageEnglish (US)
Pages (from-to)20163-20170
Number of pages8
JournalRSC Advances
Issue number43
StatePublished - Nov 21 2013


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