The structure of bubble-free gas fluidized beds of fine fluid cracking catalyst particles

✍ Scribed by L. Massimilla; G. Donsì; C. Zucchini

• Publisher: Elsevier Science
• Year: 1972
• Tongue: English
• Weight: 921 KB
• Volume: 27
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(72)87059-3

✦ Synopsis

Batches of commercial fluid cracking catalyst of broad and narrow particle size ranges were particulately fluidized by air in a 140 mm i.d. semicircular column with a transparent flat wall, and their expansion behaviour compared. The batches of narrow size range varied from 125-104 to 45-40 CL.

Cavities were discovered through a microscopic observation of the expanded beds, and a photographic study made to find out their average size, size distribution, shape and orientation. These findings were related to the observed expansion at different fluidizing velocities by means of a statistical analysis of the data.

A cellular structure was proposed, consistent with the observed lack of solids mobility in the bed. This was tested against the drag vs. particle Reynolds number relationship, for both fluidization experiments and previous experiments with regular arrays of spheres at comparable voidage.