Coal mill model considering heat transfer effect on mass equations with estimation of moisture

A nonlinear dynamic model considering the effect of heat transfer on outlet pulverized coal mass flow is established based on the principles of conservation laws. Raw coal moisture estimation which is connected to coal mass and internal energy in coal mills is included in the model. The model has proved to have good predictions and reflects the dynamics of the coal mill by verifications on historical data and dynamic simulation tests. Results show that the mean absolute error of mill differential pressure, mill electric current and outlet primary air temperature are 3.08%, 3.05% and 0.05% on validation operation data, respectively. The predictions fit the curves of the measured data that cover the whole operation of coal mill from starting up to shutting down.