A powder containing spherical particles with mean volume
diameter (dVn) of 150 micrometre and
particle density of 2800 kg/m3 is fluidised by air of density 1.2
kg/m3 and viscosity 0.0184 cp in
a column of diameter 0.5 m. The mass of powder charged to the
column is 560 kg and the flow
rate of fluidising air is 140 m3/h. Previous experiments under the
same operating conditions
produced a bubbling fluidised bed with a mean bubble size of 10 mm
(dVn).
Calculate the following:
a. the minimum fluidisation velocity (Vmf) and the bed voidage at
incipient fluidisation (?mf);
b. the bed height (Lmf ) and frictional pressure drop at incipient
fluidisation;
c. the maximum allowable air flow rate (Qmax);
d. the minimum bubbling velocity (Vmb);
e. the visible bubble flow rate (QB);
f. the gas bubble volume fraction (?B);
g. the particulate (emulsion) phase voidage (?E);
h. the mean fluidised bed voidage ;
i. the mean fluidised bed height (Lf ) and pressure drop (?Pf
).