Generally, the temperature of flue gases at the furnace outlet is not measured. Therefore, a special computation procedure is needed to determine it. This paper presents a method for coordination of the numerical model of a pulverised fuel boiler furnace chamber with the measuring data in a situation when CFD calculations are made in regard to the furnace only. This paper recommends the use of the classical 0-dimensional balance model of a boiler, based on the use of measuring data. The average temperature of flue gases at the furnace outlet tk" obtained using the model may be considered as highly reliable. The numerical model has to show the same value of tk" . This paper presents calculations for WR-40 boiler. The CFD model was matched to the 0-dimensional tk" value by means of a selection of the furnace wall emissivity. As a result of CFD modelling, the flue gas temperature and the concentration of CO, CO2, O2 and NOx were obtained at the furnace chamber outlet. The results of numerical modelling of boiler combustion based on volumetric reactions and using the Finite-Rate/Eddy-Dissipation Model are presented.

Power boilers should be characterized by high flexibility in terms of loads, which results from the demand for electricity. In addition to the flexibility of the boiler, it is also important for the boiler to operate under technical minimum conditions while maintaining harmful emissions standards. A boiler operating with a technical minimum should also exhibit a stable combustion process. The paper presents the results of numerical combustion research for the minimum load of the two-pass ultrasupercritical boiler with front wall swirl burners system. The combustion stability for the minimum boiler load of 40% for the three mill system configurations has been demonstrated. Based on the numerical tests carried out in terms of obtaining the most favourable combustion conditions and the emission of harmful substances, the most favourable of them cases was indicated.

The primary methods of reducing nitrogen oxides, despite the development of more advanced technologies, will continue to be the basis for NOx reduction. This paper presents the results of multivariate numerical studies on the impact of air staging on the flue gas temperature and composition, as well as on NOx emissions in a OP 230 boiler furnace. A numerical model of the furnace and the platen superheater was validated based on measurements using a 0-dimensional model of the boiler. Numerical simulations were performed using the ANSYS Workbench package. It is shown that changes in the distribution of air to OFA nozzles, the angle of the air outflow from the nozzles and the nozzle location involve a change in the flue gas temperature and in the volume of NOx and CO emissions at the furnace outlet.