Characterization of the fluidization behavior of different solid types based on chaotic time series analysis of pressure signals

Results from a laboratory-scale fluidized bed are presented to show that chaotic time series analysis of pressure-drop measurements can be used to distinguish the behavior patterns of four different fluidizing solids belonging to groups A, B, and D. The fluidizing solids included fluidizing cracking catalyst (group A), 35x100 mesh stainless steel (group B), 18x50 mesh stainless steel (group D), and 5 mm com (group D). The results also show that chaotic time series analysis of pressure-drop measurements can be used to detect transitions in flow regime as gas velocity is increased for a given solid. The results are based on pressure-drop measurements from a room-temperature, atmospheric fluidized bed operated over a range of air flows and settled bed heights of 28 cm, 38 cm, and 48 cm. Pressure-drop measurements are taken at the wall at two different vertical locations in the fluidized bed. One location provides the overall pressure drop while the other provides the pressure drop across a 12.7 cm-high section located at 22.9 cm above the air distributor. It will be shown that chaotic time series analysis of pressure-drop signals offers great promise of becoming a valuable supplemental diagnostic tool for detecting anomalous or undesirable behavior such as defluidization and solid agglomeration in commercial fluidized bed reactors and combustors.