Abstract. In this paper, a numerical study of the formation of nitrogen oxides in the combustion chamber based on the model created by Mitchell and Terbellom. The distribution of the height of the furnace temperature and the concentration of nitrogen oxides, as well as a comparison of numerical results with the data of field experiment.Outdoor air pollution is one of the major problems of our time due to the imperfect human activities. Artificial man-made sources of air pollution are the most dangerous, and primarily related to the combustion processes of natural fuels [1]. Approximately 40% of the total air pollutants nitrogen oxides generated by thermal power plants, burning the fossil fuels. Predicting the formation of harmful substances from fossil fuel-fired thermal power plants is one of the major challenges for the energy sector. The use of numerical methods to study not only facilitates the solution of problems, but also allows you to work out a few options of the problem, to assess structural changes and optimization of engineering solutions for these objects.In this paper we use numerical simulation of the generation of nitrogen oxides during the combustion of coal dust on the model created by Mitchell and Tarbell om [2]. This kinetic model is simple to use, as includes 13 reactions take into account the processes of exit and volatile combustion, combustion of coke particles. Model [2] gives the modern idea of aeromechanics processes leading to the generation of nitrogen oxides from the combustion of pulverized fuel [3].Analytic study of the model-Mitchell-Tarbell held in the furnace boiler BKZ 320-140 followed by verification of the results obtained with the experimental data of field experiment [4].Boiler BKZ 320-140 (see Fig. 1) burns brown coal Kansk-Achinsk [4]. Boiler designed monohull performance U-shaped layout with liquid slag removal. At around 11400 m from zero is to "survive", which separates the combustion chamber and the cooling chamber. Each of the two octagonal furnace extensions that make up the combustion chamber is equipped with four slot burners [4].Calculations were performed using: aerothermodynamic and temperature fields obtained with the application package FIRE 3D [5]; the concentration of nitrogen oxides -application package FIRE 3D-NO x [6], depending on the fuel supply speed under constant excess air at the exit of the furnace and a load of 1,27 boiler 300 t/h. As an indicator of the organization staged combustion accepted ratio = B