The impact of temperature and particle size on minimum fluidizing velocity was studied and analyzed in a small pilot scale of bubbling fluidized bed reactor. This study was devoted to providing some data about fluidization to the literature under high temperature conditions. The experiments were carried out to evaluate the minimum fluidizing velocity over a vast range of temperature levels from 20℃ to 850℃ using silica sand with a particle size of 300-425 μm

425-500 μm

500-600 μm

and 600-710 μm. Furthermore

the variation in the minimum fluidized voidage was determined experimentally at the same conditions. The experimental data revealed that the

U

mf

directly varied with particle size and inversely with temperature

while

ε

mf

increases slightly with temperature based on the measurements of height at incipient fluidization. However

for all particle sizes used in this test

temperatures above 700℃ has a marginal effect on

U

mf

. The results were compared with many empirical equations

and it was found that the experimental result is still in an acceptable range of empirical

equations used. In which

our findings are not well predicted by the widely accepted correlations reported in the literature. Therefore

a new predicted equation has been developed that also accounts for the affecting of mean particle size in addition to other parameters. A good mean relative deviation of 5.473% between the experimental data and the predicted values was estimated from the correlation of the effective dimensionless group. Furthermore

the experimental work revealed that the minimum fluidizing velocity was not affected by the height of the bed even at high temperature.