STAGNANT ZONES IN GRANULAR MOVING-BED FILTERS FOR FLUE-GAS CLEANUP

The flow patterns in three symmetric and two asymmetric louver-walled granular moving bed systems are studied experimentally. The flow patte rn histories of granular solids in moving beds were recorded by video camera throughout the whole test period. The image processing system i ncluding a frame grabber was used. Selected discrete images showing th e flow pattern development were digitized and stored in files. Individ ual granular flow frames show a development of quasi-stagnant tones cl ose to the louvered walls, the shear zones and a central flow region w ith width depending on the louver angle. The vertical shift of one or the other louvered wall in asymmetric configuration considerably influ ences the history of quasi-stagnant zones.