MONITORING THE FLUIDIZATION QUALITY IN A FLUIDIZED BED PASTE DRYING USING PRESSURE FLUCTUATION MEASUREMENTS
Flavia Tramontin Silveira Schaffka1; Carlos Alexandre Moreira da Silva2; Frederic Conrad Janzen3; Maria Regina Parise1
1 Federal University of Technology - Parana (UTFPR); 2 State University of Campinas; 3 Federal University of Technology- Paraná
doi:10.20906/CPS/COB-2015-1122
Resumo
In all gas-solid fluidized bed processes, it is necessary to maintain the fluidization quality, in order to assure the temperature and moisture uniformity, and the high rate of heat and mass transfer. For the paste drying process, for example, the injection of a paste in a fluidized bed can lead to local zones of poor mixing, and reduction in fluidization quality. Based on this fact, the purpose of the present work is to monitor the fluidization regime transitions during the course of the paste drying process using standard deviation and power spectrum analysis, which is based on pressure fluctuations measurements in the plenum. The experiments were conducted in the bench-scale fluidized bed unit constructed in Plexiglas acrylic of 0.11 m in inner diameter and 1.0 m in height, which was instrumented with a pressure transmitter connected to a data acquisition system in order to record the pressure fluctuations of the gas-solid flow. Aluminum beads with mean particle diameter of 1.55 mm were used as inert particles and the calcium carbonate suspension was used as a liquid paste sprayed onto the bed. The results showed that the fluidization quality can be monitored by the standard deviation and power spectrum techniques.
Palavras-chave: Gas-solid fluidized bed; Paste drying; Pressure fluctuation measurements