Modeling the steady-state thermodynamic operation point of top-spray fluidized bed processing

A thermodynamic computer model named Thermodynamic Operation Point Simulati on (Topsim) and programmed in Delphi, was developed to calculate the steady -state thermodynamic operation point of a fluidized bed process. The model was developed for a Glatt GPCG-1 fluidized bed unit in the top-spray config uration but the approach is perfectly transferable to other and bigger conf igurations. Convective and radiative heat losses were included in the calcu lation of thermodynamic response variables and because hear losses and outl et air thermodynamic properties are interrelated the strategy of varying th e wet-bulb temperature was developed. The principle of this calculation met hod involves a gradual decrease of the process wet-bulb temperature until t he heat loss appearing in the heat balance matches the actual heat losses. It was demonstrated that inclusion of heat losses improves clearly the mode l's performance and from validation experiments it was noticed that simulat ion of the thermodynamic operation point by Topsim is reliable. Hence, such a model helps in understanding the impact of process variables and ambient changes known as the so-called weather effect. Moreover the model can be a pplied in model predictive control of the thermodynamic operation point. (C ) 1999 Elsevier Science Ltd. All rights reserved.