Application of the Numerical Techniques for Modelling Fluidization Process Within Industrial Scale Boilers

The numerical simulation of the large scale industrial circulating fluidized bed (CFB) boilers, working under air- and oxy-fuel combustion are presented in this paper. Moreover, two-dimensional experimental rig used for numerical model validation is described. For three-dimensional numerical simulations two industrial compact CFB boilers were selected installed in Polish Power Plants. Numerical simulations were carried out using three-dimensional model where the dense particulate transport phenomenon was simultaneously modelled with combustion process. The fluidization process was modelled using the hybrid Euler-Lagrange approach. Within the paper, readers can find information about used computational technique and a number of reference to specific work. The impact of radiative heat transfer on predicted temperature profile within the CFB boiler was investigated in presented work. Moreover, the novel model for retrieving radiative properties of gases under oxy-fuel combustion process was used. The evaluated temperature and pressure profiles during numerical simulations were compared against measured data collected during boiler air-fuel operation. Collected data was also used for validating numerical model of the oxy-fuel combustion model. Stability of the model and its sensitivity on changes of composition of the oxidizer were studied. This simulations were evaluated to check the response of the numerical model on changing the combustion conditions from air- to oxy-fuel combustion process. The comparison of the pressure and temperature profiles for all considered cases gave comparable trends in contrary to measured data.