Early warning of agglomeration in fluidized beds by attractor comparison

An enhanced monitoring method, based on pressure fluctuation measurements, for observing nonstationarities in fluidized-bed hydrodynamics is presented . Experiments show that it can detect small changes in the particle-size di stribution. Such a monitoring method is useful to give an early warning of the onset of agglomeration in a fluidized bed. In contrast to earlier metho ds, this method is insensitive to small changes in superficial gas velocity and can handle multiple signals, making it relevant to industrial applicat ion. By carefully choosing the measurement position, the method becomes als o insensitive to small bed mass variations. rt uses the attractor reconstru cted from a measured pressure signal, which is a "fingerprint" of the hydro dynamics of the fluidized bed for a certain set of conditions. Using this m ethod statistically the reconstructed attractor of a reference time series of pressure fluctuations (representing the desired fluidization behavior) i s compared with that of successive time series measured during the bed oper ation.