The Dynamic Simulation Of The Combustion System In The 440t/h CFB

Circulating Fluidised Bed(CFB) boiler is widely used in the world, because of the characteristics of fuel flexibility, high combustion efficiency and low pollution emissions. At present, CFB is heading for the large-scale. But the CFB, which is running now, is almost in miniature. There is a barrier to develop CFB capability, since little design technology and the dynamic characteristics are known for large CFB. Since that, it's necessary to know more about the running characteristics of the large-scale CFB, to resolve this problem. It has been proved that the computer simulation is a convenience and fast way to roundly know the dynamic characteristics of the large CFB based on the practical experiment. As one part of the Visual Modelling Simulation system of large scale CFB, a dynamic mathematical model of the combustion system about the large scale CFB is developed in this paper. The characters of the gas and solid flowing, the voltage releasing and combusting, the coke combusting, the forming and reducing of the pollution, the abrasion of the solid and the heat transfer are all adequately considered in this model. And the distribution character of the thermal parameter is also considered by the cell model in the direction of axial, and the core-annulus structure in the direction of radial. Based on the mass conservation law, the energy conservation law and some empirical equations, the dynamic model is built. This simulating model is developed by the method of object-oriented module. Considering the universal and the easily programming of the model, the Fortran90 is chosen as the programming language. Considering the stiff of the model equation, decided by the system character, the Gear method is chosen to differentiate, as solving the equations. Some simulation experiments on the dynamic character of large-scale CFB are made using the 440t/h CFB as an object by the software VMS. The model is verified by the data of the experiment. The model provided an easy and fast experimenting method for designing and operating the large CFB.