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http://dx.doi.org/10.5855/ENERGY.2011.20.3.191

Comparative Study of Char Burn-Out and NOx Emissions in O2/N2 and O2/CO2 environments  

Lee, Chun-Sung (Graduate School of Mechanical Engineering, Pusan National University)
Kim, Seong-Gon (Graduate School of Mechanical Engineering, Pusan National University)
Lee, Byoung-Hwa (Graduate School of Mechanical Engineering, Pusan National University)
Chang, Young-June (School of Mechanical Engineering, Pusan National University)
Jeon, Chung-Hwan (School of Mechanical Engineering, Pusan National University)
Song, Ju-Hun (School of Mechanical Engineering, Pusan National University)
Publication Information
Journal of Energy Engineering / v.20, no.3, 2011 , pp. 191-199 More about this Journal
Abstract
The char burn-out and NOx emissions from sub-bituminous coal were investigated in drop tube furnace under $O_2/N_2$ and $O_2/CO_2$ environments with different $O_2$ concentrations of 12, 21 and 31%. Results show that the char burn-out rate is faster as $O_2$ concentration increases higher and char burn-out rate under $O_2/CO_2$ decreases due to the lower oxygen diffusion into coal surface through the $CO_2$ rich boundary layer. NO concentration increases with increasing $O_2$ concentration, but declines at $O_2$ concentration of 31%. Meanwhile, NO emission indexes decreases monotonically with increasing $O_2$ concentration, which indicates that more NO reduction occurs with higher $O_2$ concentration probably due to greater HCN formation. For all conditions of $O_2$ concentration, the NO concentration under $O_2/N_2$ maintains higher than those of $O_2/CO_2$ due to presence of thermal NO.
Keywords
Oxy fuel combustion; $O_2$ concentration; NO reduction; char burnout;
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