Performance prediction of the tangentially fired pulverised-Coal boiler furnace using a mathematical model and its validation

A simple thermodynamic model is developed for performance prediction for a tangentially fired pulverized-coal boiler furnace. For this purpose, the furnace is sliced into number of zones of rectangular parallelepiped. These zones are further divided into heat release zones and non-heat release zones. The major sub-routines of the program include framing equations for the definition of the heat release zones, a reasonably approximate flow model to simulate tangential firing, radiation formulation and equations for the calculation of emissivity of CO2 and H2O. A few of the inputs required for this model have been obtained from offline-CFD simulations. The solution for the model's equations is obtained using the Newton Raphson method. The outputs of the program include the variation of the heat flux along with the height of the boiler furnace and furnace exit gas temperature (FEGT). The influence of operating conditions on the furnace in terms of its performance is also studied. The FEGT predicted using the mathematical model is in fairly good agreement with the site measured data. The model can be used as an effective tool by powerplant operators to optimize the performance of the boiler furnace.