A study of aggregative fluidization

The effects of size distribution on the expansion of a gas‐solid fluidized system have been studied by the fluidization of glass beads and char particles by air in a 2 1/4 inch diameter column. Log‐probability distributions of 5, 10, 25 and 100‐fold size variation, with an average size of 271 microns, were tested, and changes in the average diameter of the bed due to elutriation were obtained. Systematic tests with beds of closely sized particles ranging in size from 74 to 912 microns were also made. The results show that compared with the effect of particle diameter, size distribution has little influence on the shape of the bed expansion curves. Various correlations, and in particular that suggested by Zenz for particulate fluidization, have been tested using the single size measurements. It is concluded that up to the present time, no really satisfactory correlation for aggregative fluidization has been proposed.