CFD Simulation of Inverse Fluidization
The term 'fluidization' is associated with two or three phase systems, in which the solid particles are fluidized by a liquid or gas stream flowing in the direction opposite to that of gravity. Fluidization, where the liquid is a continuous phase is commonly conducted with an upward flow of the liquid in liquid-solid systems or with an upward co-current flow of the gas and the liquid in three phase systems. Under these conditions, a bed of particles with a density greater than that of the liquid is fluidized with an upward flow of the liquid counter to the net gravitational force of the particles. Fluidization can be achieved by downward flow of the liquid when the particles have lessdensity than the continuous liquid medium and this phenomenon is termed as inverse fluidization. The inverse fluidization system has gained significant importance during the last decade in the field of environmental, biochemical engineering and oil–water separation. The minimum fluidization velocity is lower in this case. Also, it takes lessenergy to pump a fluid to force the particles. Hence, at the industrial level, it can save a lot of energy. Such energy efficient processes are the need of today when energy crisis is at its peak. The application of inverse fluidization technique in biotechnology is one of the most important areas in bioreactor engineering. In this report various hydrodynamic characteristics of the inverse fluidized bed is studied based on literature and CFD is applied on the system for further analysis.
Key Words - Fluidization, inverse fluidization, three phase systems, oil-water separation and CFD simulation