A numerical model for the gas-particle flow dynamics has been combined with a NOx- chemistry post-processor to predict the formation of nitric oxide in a three-dimensional, W-shaped boiler furnace burning pulverized fuel. The model includes the complex interaction of gas-particle turbulent flow, heat transfer, gaseous chemical reaction, coal combustion, and NOx reaction chemistry. Because the fuel nitrogen is released in proportion to the burnout of the pulverized coal particles, the particles are treated in a Lagrangian framework in order to track burning pulverized coal particles through the gas continuum. The results show the capability of the model for describing NOx emissions under different operating conditions for full and partial load.