Application of the theory of Markov chains to theoretical study of processes in a circulating fluidized bed

Abstract

The objective of the study is to develop a simple yet informative model to investigate the features of the process of particulate flows formation in a circulating gas-solid fluidized bed. The proposed model is based on the theory of Markov chains. The riser is presented as a chain of perfectly mixed cells. The conversion of particles of a source material into particles of an end product occurs in these cells due to this or that chemical or thermo-physical process. The transportation of material over the chain is controlled by a matrix of transition probabilities. The return flow that comes from a separator is routed to the downer, which is described as a plug flow apparatus that has a time delay between the inflow and outflow issuing from it. The outflow is routed back into the riser. The numerical experiments were carried out for the batch fluidization. It is found that the batch circulating fluidization only has advantages over the dense bed under a small time delay in the downer and a relatively high gas flow velocity in the riser. The results of laboratory tests performed at the circulating fluidized bed demonstrated a good qualitative correlation with the theoretical data.