In designing fluidized bed, it has been the most difficult problem that the basic data obtained by the small scale apparatus are not applicable for the design of the large diameter commercial scale plant.
One of authors has proposed, as a scale-up method, to divide the large diameter fluidized bed into elementary compartments by internal vertical walls with holes of optimum area, so that each compartment can maintain the fluidization quality equal to the elementary small scale apparatus.
In this work, the scale up method was checked by the measurements of the rate of solids mixing. And the reproducibility in both elementary small scalle 6 ㎝ equivalent diameter apparatus and scaled up one was assured. This shows a possibility of practical use of this method in commercial scale plant design.