ARTICLE INFO Keywords: Oxy-fuel combustion Particle motion Heterogeneous reaction characteristics CFD modeling Surface Damko spexpressioncing diexpressioneresis hler number

Research and development of low-carbon combustion technology are necessary to satisfy the requirements of carbon neutrality. Oxy-fuel combustion technology is deemed a promising low-carbon technology it requires further investigation due to N-2 replacement by CO2. This study aims to investigate the effects of particle motion modes (i.e., translation and rotation) and their speeds on char reaction characteristics under air-and oxy-fuel combustion. The translational and rotational speeds are described by the particle Reynolds numbers R-ep and particle swirl Reynolds numbers Re-p,Re-w, respectively. The results indicated that the flame peak temperatures were reduced by 5.1% and 20.4%, and the particle temperatures were decreased by 13.1% and 9.2% under air-and oxy-fuel combustion, respectively, with an increase in the Rep values. However, the peak temperatures of the flame and particle were minimally affected by different Re-p,Re-w values. Char consumption rates and the reduced effects on the rates due to N-2 replacement by CO2 were enhanced when the Rep values increased. The rates remained nearly unchanged, and the reduced effects remained constant at ~20% with an increase in the Ree(p, w) values. The proportions of each heterogeneous reaction were nearly unaffected by the increase in the Re-p and Re-p,Re- w values, the proportion of gasification reaction increased with N-2 replacement by CO2, and the surface Damkohler numbers (Das) of oxidation and gasification reactions were predicted. The Da(s,oxi) and Da(s,gas) values decreased significantly with an increase in the Rep and Re-p,Re- w values from 0 to 150. The Das values affected by rotational motion speeds (Re-p,Re- w) were more significant than those affected by translational motion speeds (Re-p).

Automated summary

This study investigated the effects of particle motion modes and speeds on char reaction characteristics, revealing some impact on char consumption rates.