Flow patterns in a pilot plant-scale turbulent fluidized bed reactor: Concurrent application of tracers and fiber optic sensors

Hydrodynamics of a turbulent fluidized bed is studied by means of the concurrent application of fiber optic sensors and a helium tracer. It is observed that in the vicinity of the column wall there is a high bubble activity region. Low bubble activity and negative bubble velocities are reported for the dense phase near the column centre-line region. A temperature increase from 22 to 145 degrees C results in a more homogeneous turbulent fluidized bed with smaller bubbles and more gas flowing through an expanded dense bed emulsion phase. Mass transfer coefficients between bubble-emulsion (k(be)) and babble-annulus (k(ba)) are evaluated. The dominant mass transfer path was the one from the bubbles to the annular region with k(ba) being several times greater than k(be).