Synergetic NO reduction by biomass pyrolysis products simulating their reburning in circulating fluidized bed decoupling combustion

doi:10.1016/j.cjche.2018.07.002

Abstract

Abstract: The present work investigated the synergetic effect of pyrolysis-derived char, tar and gas (py-gas) on NO reduction, which may occur in circulating fluidized-bed decoupling combustion (CFBDC) system treating N-rich fuel. Experiments were carried out in a lab-scale drop-tube reactor for NO reduction by some binary mixtures of reagents including char/py-gas, tar/py-gas and tar/char. At a specified total mass rate of 0.15 g·min^-1 for NO-reduction reagent, the char/py-gas (binary reagent) enabled the best synergetic NO reduction in comparison with the others. There existed effective interactions between char and some species in py-gas (i.e., H₂, C_xH_y) during NO reduction by pyrolysis products, meanwhile the tar/py-gas or tar/char mixture only caused a positive effect when tar proportion was necessarily lowered to about 26%. On the other hand, the synergetic effects were not improved for all tested binary reagents by increasing the reaction temperature and residence time.

Key words: Biomass, Pyrolysis, Circulating fluidized bed, NO reduction, Synergetic effect, Decoupling combustion

摘要： The present work investigated the synergetic effect of pyrolysis-derived char, tar and gas (py-gas) on NO reduction, which may occur in circulating fluidized-bed decoupling combustion (CFBDC) system treating N-rich fuel. Experiments were carried out in a lab-scale drop-tube reactor for NO reduction by some binary mixtures of reagents including char/py-gas, tar/py-gas and tar/char. At a specified total mass rate of 0.15 g·min^-1 for NO-reduction reagent, the char/py-gas (binary reagent) enabled the best synergetic NO reduction in comparison with the others. There existed effective interactions between char and some species in py-gas (i.e., H₂, C_xH_y) during NO reduction by pyrolysis products, meanwhile the tar/py-gas or tar/char mixture only caused a positive effect when tar proportion was necessarily lowered to about 26%. On the other hand, the synergetic effects were not improved for all tested binary reagents by increasing the reaction temperature and residence time.

关键词: Biomass, Pyrolysis, Circulating fluidized bed, NO reduction, Synergetic effect, Decoupling combustion

Hai-Sam Do, Tuyet-Suong Tran, Zhennan Han, Xi Zeng, Shiqiu Gao, Guangwen Xu. Synergetic NO reduction by biomass pyrolysis products simulating their reburning in circulating fluidized bed decoupling combustion[J]. Chinese Journal of Chemical Engineering, 2019, 27(7): 1680-1689.

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