Prediction of NOx during pulverized coal combustion:Parameter database and CFD application

In the previous work,a new NOx prediction model for pulverized coal combustion has been developed;the concentrations of CO and H2 were used to represent the fraction of CHi to quantitatively describe NOx gas phase reduc- tion;by making codes,the new NOx model and char burning model considering gasification reactions were implemented with Fluent. Based on this,a drop tube furnace (DTF) and a one-dimensional furnace were updated and the combus- tion experiments of different coals under different conditions were conducted to collect experimental data of high quali- ty. The parameter database of the new NOx model was built via the simulations of such basic experiments. Finally,the developed NOx model was successfully applied in the CFD simulations of tangential-fired boiler,opposed firing boiler and W-shaped flame boiler. Simulation results of three types of boilers under different operational conditions indicate that the new NOx model is able to accurately simulate the effects of different coals,different boiler types and different operational conditions on NOx evolution. This work provides a model basis for the further design,modification and opti- mization of low-NOx burner and boiler.