Approaches to controlling NOx emission have been investigated worldwide. Numerical simulation models describing gas-particle flow, heat transfer, and combustion processes are presented in this paper to provide reasonably accurate predictions of the flow field, temperature field, and the distribution of chemical species in a W-shaped furnace. The predictions indicate that the temperature field of model II is more uniform and the contour is lower due to the complement of nozzles. It results in the decrease of NOx formation. Comparison about NOx emission of two furnace models at different temperatures has been made, it shows that the furnace of model II is better in reducing the emission of NOx.