(99g) Verification of a Binary Mixing Process of Particulate Solids in a Fluidized Bed Predicted with the Theory of Markov Chains

Experimental investigation has been carried out to study the evolution of concentration of components in a binary mixture of particulate solids in a laboratory cylindrical fluidized bed. The fluidized bed is 250 mm in diameter and 800 mm in height. It was initially loaded with two kinds of particulate solids in layers. The particulate solids used were almost spherical, but varied in size and/or density. The fluidization bed was operated with different gas flow rates; meanwhile, samples were taken at some designated locations in four levels along the fluidization column with a predefined interval. The components of solids in samples were measured with image processing and/or sieving technique; and the evolution of concentration of particulate solids (i.e. the mixing process of material) was therefore investigated.

A mathematical model to describe the process was also proposed. In the model, the volume of fluidized bed is represented as a sequence of perfectly mixed cells along the bed height, the mixing process of solids was modeled based on the theory of Markov chains. Comparisons were made between the results predicted with the mathematical model and the experimental data obtained. The model is subjected to further improvement, at the same time the processing of binary mixing in a fluidization bed was addressed with regard to the density and size of particulate solids.