Numerical simulations were conducted to investigate the interplay of combustion and decomposition and the associated NOx conversion within a precalciner with burners.A multiple surface reactions model was used to char burning,with a particular focus on the mechanisms governing the combustion of pulverized coal.CO2 partial pressure's impact on raw meal decomposition was considered by customizing the reaction rate.The conversion of NOx was studied by analyzing CO and NO interaction.Simulation results were in reasonable agreement with engineering data.The results indicate that the presence of the burners makes pulverized coal near the wall and combustion along it,which is likely to damage precalciner wall.Notably,pulverized coal exhibits a high burnout rate,and the main combustion zone is located in the range of 2.53-7.73 m.The raw meal is decomposed rapidly at the height of 9.04 m after entering into the precalciner,with a final decomposition rate of 91.7％.Due to the initial decomposition site of the raw meal is higher than that of the main combustion zone of pulverized coal,pulverized coal combustion and the decomposition of the raw material is poorly coupled on the whole,and there are two obvious local high temperature zones in the precalciner.Furthermore,the combustion of pulverized coal from the graded coal pipe yields a substantial amount of CO,effectively reducing NO from the flue gas chamber,with a reduction rate of 57.5％.
维普
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