MECHANISM OF FAST FLUIDIZATION AND VERTICAL PROFILE OF SOLID CONCENTRATION IN FAST FLUIDIZED-BEDS - (REGIME OF FAST FLUIDIZATION)

The gas velocity in the circulating fluidized beds of, for example, al uminum ore calciners, petroleum crackers and boilers is larger than th e particles' terminal velocity, We propose the growing chain model, in which the particles form vertical chains in the fluidized bed, in ord er to determine theoretically the regimes of fast fluidization. Compar ing the fluidization condition empirically recognized as the optimum o perating condition for the circulating fluidized bed in boilers, the m aximum fast fluidization gas velocity is found to coincide with the te rminal velocity of an infinitely long chain, which is about twice as h igh as that of a single particle.