Towards a continuous pilot scale pyrolysis based biorefinery for production of biooil and biochar from sawdust

摘要

Sawdust was first pyrolysed in a fixed bed batch scale reactor at temperatures between 400 degrees C and 600 degrees C. Optimum temperature for pyrolysis of sawdust was found to be 500 degrees C; at which, bio-oil (34.9 wt%), bio-char (38.6 wt%) and pyro-gas (26.5 wt%) were obtained. Subsequently, the reaction was scaled-up using a vertical moving bed type continuous reactor (capacity 15 kg/hr) and at 500 degrees C, the obtained yields of products were 41.05 wt% of bio-oil, 27.59 wt% of bio-char and 31.36 wt% of pyro-gas (mixture of non-condensable gases). Bio-oil was characterized using H-1 and C-13 NMR, FT-IR and GC-MS. GC-MS analysis indicates that 71 chemical compounds are present in bio-oil. The bio-char was characterized using TGA, FT-IR and SEM; these analyses showed that, it is porous in nature and contain negligible amount of volatiles. In addition, the GC analysis of pyro-gas confirms that, different gases viz. H-2 (1.59 vol%), N-2 (13.61 vol%), O-2 (2.48 vol%), CO (54.23 vol%), CH4 (8.02 vol%) and CO2 (24.72 vol%) are present in it.Under optimized reaction condition, during batch pyrolysis, bio-oil yield was 34.9 wt% and bio-char yield was 38.6 wt%; whereas continuous pyrolysis gave 41.05 wt% and 27.59 wt% yields for bio-oil and bio-char respectively.