A Computer Model for the Cement Kiln

A dynamic model for a cement rotary kiln is proposed. It is simple enough for computer application, yet takes into account all the operational parameters actually encountered in real practice, and thus is capable of identifying the effective controlling decisions in order to realize a desired gas temperature profile, essential for optimal clinker production. The model is built in two parts. The first represents the solid-gas interchange. Its solution yields the gas temperature profile needed for good clinkering. The second represents the gas-coal dust interchange. Its solution yields the operating parameters needed to realize the desired gas temperature with a good burning of coal dust and minimal coal waste. The first part of the model is made of two and the second part of three nonlinear partial differential equations, with the independent variables being the time t and the longitudinal position x along the kiln. Boundary conditions are dictated by the operating conditions. Initial conditions are obtained by solving the static model. An example is worked out to show how the model helps to choose the coal dust input, the coal dust diameters, and other operational parameters for a good operation of the kiln. It also shows to what extent the burning of coal dust and the resulting gas temperature profile are influenced by the various operational parameters.