The fluidization characteristics of large particles (1000-2000 pm) have been studied using bed depths up to 30 cm in equipment having a cross-section 61 x 61 cm. Results are compared with data obtained earlier using a two-dimensional bed.
The size of bubble eruptions, together with bubble frequencies and concentrations at the bed surface, were measured from tine film. Visible bubble flow rates were calculated using these data and found to be about 55 per cent of the excess gas flow. Empirical equations are presented relating these parameters with bed height and gas flow rate.
The velocities of single bubbles measured using an inductance probe and simultaneous tine photography, agreed well with the Davies-Taylor equation.
An unusual bubble formation mechanism gave rise to horizontally aligned swarms of bubbles. These appear to be peculiar to large particle systems and result in large vertical oscillations of the bed surface and severe vibration.
Another unusual feature of this large particle system was that non-coalescing bubbles were observed to expand rapidly as they rose through the two-dimensional bed. Q Q PDA,.,JD,~,~ 1.. L.. "MI._ *l-Y ."l-l n CFI n.tr)?--.*.d Y. VIIYc.I..