The influence of gas pulses on bubble size in a dual distributor fluidized bed

The goal of this work was to investigate the effect of gas pulses on bed hydrodynamics, especially on the bubble size by way of monitoring and analyzing pressure fluctuations within the dense region of fluidized bed. Experiments were performed in a laboratory scale (0.255 m ID, 1.680 m height) Plexiglas dual distributor fluidized bed reactor with sand particles of Geldart B type.; The distribution of gas pulses at the required direction and location into the dense region of a fluidized bed was achieved by designing and fabricating a combination of multiorifice and nozzle type distributor plate. Distributor plate has an open area of 2.3% where 297 orifices of 2 mm in diameter were drilled onpitch circles equal to radial pitches. Four nozzles with 11 mm inside diameter each of them having 5 orifices of 5 mm in diameter are mounted in a distributor plate in a distance of 98 mm from the plate center. The gas pulses has been introduced into the dense bed at seven different combinations. The maximum number of orifices that could be opened at the same time for each nozzle was two. Other three were screwed and were opened according to the experiment be made. The duration of the gas pulses was 0.5 second and was achieved using a home made high-speed valve.; To evaluate the influence of the gas pulses on bubble size within the fluidized bed a high-speed low-pressure computer controlled data acquisition system was developed. Pressure fluctuations were monitored and analyzed to evaluate the performance of the gas pulses. Data were acquired using low dead volume. (Abstract shortened by UMI.)...