Mathematical model on heat flux analysis of water wall in 1000MW USC boiler furnace combustion zone

In order to study the heat transfer between the flue gas and water wall, according to the 1000MW ultra super critical boiler, the flue gas temperature in the furnace, the heat flux in the water wall, the medium temperature in the tube, and ash fouling temperature in different conditions are calculated and compared with the date onsite based on the mathematic model in this paper. The model is composed with the coal combustion and radiation transfer in engineering simplification, and based on the Russia Power Station Boiler Thermodynamic Calculation Method Published in 1998. The results in different excess air coefficient conditions show that the flame temperature in the furnace and the maximum heat flux and ash fouling temperature on the water wall, and application of Air Staged Combustion Technology makes the flame radiation heat transfer distribute evenly and maximum value decrease so that NOx emission reduces and water wall safety is available. This model verified by the plant data can predict the maximum heat transfer position in the heat surface so that the tube overheating and explosion can be avoided which is important for the boiler running.