Among different gasification technologies, Circulating Fluidized Bed (CFB) is ascertained to be appropriate for the gasification of the Indian coal. The gasification process involves a mixture of particles which differ in size or shape or density (eg. coal and inerts). The physical and chemical processes taking place simultaneously may further lead to the formation of different size, shape, and density of the particles (eg. unreacted coal, ash and, clinker) in the bed giving rise to a complex flow behavior which is unsteady. Such inherently unsteady flow influences the heat transfer, mass transfer and reaction performance of a fluidized bed. The performance of such fluidized bed gasifier can be improved by understanding the complex interaction between the gas and solid phases. In the literature the CFD models on fluidized bed gasifier predict the outlet species composition and temperature reasonably well, but prediction of unsteady flow dynamics is still a challenge. Therefore predicting the phases distribution and velocity profiles are a prerequiste for predicting the species composition and temperature profiles. To validate such CFD model rigorously, spatial and time-resolved measurements of local solid hold-up and velocities are important. These experimental measurements are also crucial in characterizing the binary fluidization behaviour.

         In the present work, the dynamics of binary fluidization is being characterized by the local solid volume fraction fluctuations measured using ECT in the fluidized bed. The CFD model at cold flow conditions will be validated with these experimental measurements and the gasification kinetics of Indian coal will be included into the experimentally validated CFD model.