A MODEL TO DESCRIBE THE TRAJECTORIES OF PACKING ELEMENTS IN A DRY- TURBULENT BED CONTACTOR

The trajectories of solid particles in a gas-solid flow through a Turbulent Bed Contactor (TBC) are modeled. The model column is a tower of one meter in height and 10 cm in diameter whilethe particles are hallow spherical balls of poly-ethylene with a diameter of 1 cm. Using Lagrangianapproach for the discrete particles phase, the motion of individual particles is obtained by solving the Newton's second law of motion while the continuum gas is simply assumed to have a uniform velocitydistribution at each cross sectional area of the column. The equations of motion for a system ofparticles are solved by the 4th order Runge-Kutta method and the trajectories of a string of four particles in the tower are obtained and drawn at different gas flow rates. The collisions of particles byeach other and to the top strainer of the column are also considered in the model. The model shows theminimum gas flow rate which is required to start fluidization and collisions of the particles in the tower while it is capable to present the reasons that cause bed expansion. The maximum gas flow rate which can cause collision of the particles with the top strainer is also predictable in the model. All of themodel predictions are consistent with the experimental observations of the previous investigators who were working on the hydrodynamics of turbulent bed contactors.

Keywords:

trajectory of packing elements , turbulent bed contactor , dry bed contactor