TY - JOUR
T1 - Analysis and modeling of char particle combustion with heat and multicomponent mass transfer
AU - Umetsu, Hiroki
AU - Watanabe, Hiroaki
AU - Kajitani, Shiro
AU - Umemoto, Satoshi
N1 - Funding Information:
The experiments carried out for the comparison with the simulations in this study were funded by New Energy and Industrial Technology Development Organization (NEDO) programmed “Innovative Zero-emission Coal Gasification Power Generation Project”, P08020. I would like to express my gratitude to NEDO for their financial support.
PY - 2014/8
Y1 - 2014/8
N2 - A char combustion model suitable for a large-scale boiler/gasifier simulation, which considers the variation of physical quantities in the radial direction of char particles, is developed and examined. The structural evolution within particles is formulated using the basic concept of the random pore model while simultaneously considering particle shrinkage. To reduce the computational cost, a new approximate analytical boundary condition is applied to the particle surface, which is approximately derived from the Stefan-Maxwell equations. The boundary condition showed reasonably good agreement with direct numerical integration with a fine grid resolution by the finite difference method under arbitrary conditions. The model was applied to combustion in a drop tube furnace and showed qualitatively good agreement with experiments, including for the burnout behavior in the late stages. It is revealed that the profiles of the oxygen mole fraction, conversion, and combustion rate have considerably different characteristics in small and large particles. This means that a model that considers one total conversion for each particle is insufficient to describe the state of particles. Since our char combustion model requires only one fitting parameter, which is determined from information on the internal geometry of char particles, it is useful for performing numerical simulations.
AB - A char combustion model suitable for a large-scale boiler/gasifier simulation, which considers the variation of physical quantities in the radial direction of char particles, is developed and examined. The structural evolution within particles is formulated using the basic concept of the random pore model while simultaneously considering particle shrinkage. To reduce the computational cost, a new approximate analytical boundary condition is applied to the particle surface, which is approximately derived from the Stefan-Maxwell equations. The boundary condition showed reasonably good agreement with direct numerical integration with a fine grid resolution by the finite difference method under arbitrary conditions. The model was applied to combustion in a drop tube furnace and showed qualitatively good agreement with experiments, including for the burnout behavior in the late stages. It is revealed that the profiles of the oxygen mole fraction, conversion, and combustion rate have considerably different characteristics in small and large particles. This means that a model that considers one total conversion for each particle is insufficient to describe the state of particles. Since our char combustion model requires only one fitting parameter, which is determined from information on the internal geometry of char particles, it is useful for performing numerical simulations.
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U2 - 10.1016/j.combustflame.2014.01.029
DO - 10.1016/j.combustflame.2014.01.029
M3 - Article
AN - SCOPUS:84902378540
VL - 161
SP - 2177
EP - 2191
JO - Combustion and Flame
JF - Combustion and Flame
SN - 0010-2180
IS - 8
ER -