MODELING OF PARTICULATE MATERIAL DRYING IN A FLUIDIZED BED
To develop rational designs of units and optimum modes of drying it is necessary to know the kinetic regularities of the process and the conditions of its modeling. Using two approaches for modeling a statistical model and a model in generalized coordinates of the particulate material drying in a fluidized bed were obtained. The advantages and disadvantages, as well as the application of the developed models are shown. The first model was developed using a semi-empirical zonal method of calculation and is valid for mathematical description of the kinetics of the studied object drying. The model is more accurate, while the number of significant figures in this equation is due to the required accuracy of approximation of experimental data. However, the result of the calculation when using this model in the maximum possible form is individualized. The mathematical model in generalized coordinates was developed for possible applying of research results on kinetics of drying to similar materials taking into account invariance of criteria and simplexes of similarity. It can be used in the design of rational fluidized bed dryers for transition from a laboratory scale to the industrial one with a sufficient degree of reliability. In this case, the final transfer to the data relating to an individual specific process takes place at the last stage of the investigation and is reduced to the substitution of the numerical values of the parameters in the dimensionless equation. A generalized equation is a more streamlined presentation of the results than empirical ones. The methods in which specific tasks are put in the numerical form have the dominant value because of the great complexity of the processes of heat transfer. The model generality remains a major problem due to the lack of basic data. Design, maintenance and optimization of industrial dryers require a comprehensive mathematical model synthesizing accuracy, generality and simplicity.