Experimental and cfd simulation study of binary solid-liquid fluidized bed

Abstract

Solid liquid fluidization experiments were carried out for binary mixture of iron ore-quartz and chromite-quartz.All the experiments were performed with close size range particles to reduce the size and shape effect of the particles. It has been found that weight ratio of flotsam and jetsam affect the expansion of the fluidized bed. It was also found that particle density affect the bed expansion and other hydrodynamic characteristics. Also a feed for liquid/solid fluidization observed three types of binary system, (a) easily separable (b) difficult to separate (c) non separable. For an unstable binary fluidized bed system corresponding to a pure heavier particle bottom of the bed, lighter particles segregate at the top, and some particles neither segregate nor sink, and they missed place at the middle. Therefore knowing the physical properties of the mineral particles, an appropriate fluidization can be chosen.
The objective of the CFD analysis in this study is to investigate numerically the hydrodynamic behaviour of a liquid- solid fluidized bed. The methodology used in CFD to solve problems relating mass, momentum and heat transfer and the details about problem description and approach used in ANSYS FLEUNT 13.0 to get the solution. Finally results of simulation and comparison with experimental results are shown. CFD predicts the flow characteristics, bed hydrodynamics etc. The simulation is done for a column of 150cm height and 10cm diameter filled with 125µm iron ore, chromite and quartz mixture till a certain height. It is observed that the bed expands considerably with increase in water velocity.
Key Word: Liquid-solid fluidization, segregation, bed expansion, flotsam, jetsam, CFD