Pilot scale oxidative fast pyrolysis of sawdust in a fluidized bed reactor: A biorefinery approach

Oxidative fast pyrolysis of sawdust was performed in a pilot scale fluidized bed system (3 kg/h) under stabilized experimental conditions (0.20 equivalence ratio and 550 degrees C). Experiments were performed in non-catalytic and catalytic (ZSM-5) mode. During non-catalytic fast pyrolysis, bio-oil (similar to 38 wt%), bio-char (similar to 12 wt%) and pyrogas (similar to 50 wt%) were obtained; in contrast, for catalytic fast pyrolysis bio-oil, bio-char and pyro-gas yields were similar to 44 wt%, similar to 4 wt% and similar to 52 wt% respectively. The obtained bio-oil was characterized through CHNSO, NMR (H-1 and C-13 NMR), FT-IR and GC-MS techniques. GC-MS analysis of the bio-oil shows it is a mixture of similar to 21 chemical compounds. Furthermore, NMR (H-1 and C-13 NMR) and FT-IR results indicates presence of hydrocarbon, alcohol, phenol and aldehyde in the bio-oil. The TGA of bio-char shows that it is stable up to 950 degrees C. The activation energies (Ea) of sawdust and bio-char are found to be 112.3 kJ/mol and 46.92 kJ/mol respectively. FT-IR analysis of bio-char clearly revealed removal of functionalized organic compounds during devolatilization of sawdust. In addition, GC analysis of pyro-gas suggests that it is a mixture of N-2 (35.55 vol%), CO (34.49 vol%), CO2 (16.80 vol%), H-2 (4.54 vol%), O-2 (4.25 vol%), and CH4 (4.41 vol%).