Evaporation system modeling of the utility boiler aiming at real-time estimation of the heat flux into water walls

A lumped-parameter model for natural circulation drum-boilers is proposed to calculate the heat flux transferred into water wall tubes. The complicated dynamics of the entire evaporation system is described, including drum, downcomers and riser components. Based on the mass and energy balances, the model is characterized by only a few physical parameters. The heat flux into water wall tubes can be determined without any combustion conditions of the furnace. The model validation is carried out by using the industrial data of a coal fired power plant. The dynamic properties of the heat flux may be captured over a wide range of operating, which may potentially be applied for real time estimation of heat generation in the furnace and lower heating value (LHV) of the coal.