Factors affecting density transients in a fluidized bed

Abstract

Abstract The effects of five operating variables on the uniformity of fluidization in a 4‐in.‐diameter column were determined by a statistically designed experiment. Density fluctuations inside the bed were measured by a capacitance method. Certain parts of the experiment were repeated in a 24‐in.‐diameter column for comparison with the 4‐in.‐column data. In the 4‐in. column gas velocity had by far the greatest effect on uniformity, with uniformity generally decreasing with an increase in gas velocity. This is consistent with the theory that most gas introduced in excess of the rate for incipient fluidization passes through the bed in the form of various‐sized bubbles. Better uniformity at the lower bed level indicates that bubbles grow in size as they proceed up the column. An entirely different gas‐flow pattern was indicated in the 24‐in. column.