Pyrolysis characteristic changes of poplar wood during natural decay

Author

TipengWangRunheZhangLiPengYinongAiQiangLu

National Engineering Laboratory for Biomass Power Generation Equipment, North China Electric Power University, 2 Beinong Lu, Beijing 102206, China

Received 1 June 2017, Revised 25 September 2017, Accepted 2 October 2017, Available online 4 October 2017.

Highlights

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Pyrolysis characteristic changes of poplar wood during natural decay were studied.

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With an increase of decay degree, the pyrolysis behaviors of PW were more and more close to that of the MWL.

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The E value decreased from 91.37 to 74.08 kJ/mol with an increase of decay degree from 0 to 60 wt.%.

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High decay degree was contributed to improve the pyrolysis selectivity of PW to phenols.

Abstract

To explore the pyrolysis characteristic changes of wood during natural decay, 4 different degrees of decay of poplar wood (PW) were chosen and pyrolysis behaviors were studied by TGA and Py-GC/MS. The results indicated that with an increase of decay degree from 0% to 60%, the contents of hemicellulose and cellulose decreased from 22.2 and 46.39 wt.% to 11.77 and 22.32 wt.%, and that of lignin and extractives increased from 23.9 and 6.60 wt.% to 39.85 and 20.84 wt.%, respectively. The pyrolysis processes mainly happened in two stages. Lower degrees of decay did not have much influence on the pyrolysis behaviors, but with an increase of the decay degree, the pyrolysis behaviors were much more similar to those of the milled wood lignin from PW. The changes of the physical and chemical structures resulted in the decrease of Activation Energy from 91.37 to 74.08 kJ/mol. Meanwhile, in the bio-oil, the contents of the ketones, carbonyls, sugars and furans changed slightly from 15.67%, 4.61%, 8.31% and 7.86% to 12.52%, 3.32%, 7.90% and 6.46%, respectively. However, the content of the acids decreased from 19.03% to 11.25%, and that of phenols significantly increased from 22.52% to 35.97%. Therefore rotten wood could be used as the feedstock of the selective pyrolysis to product the phenols.

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