Modification and re-interpretation of Geldart's classification of powders

✍ Scribed by Wen-Ching Yang

• Book ID: 104088549
• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 582 KB
• Volume: 171
• Category: Article
• ISSN: 0032-5910
• DOI: 10.1016/j.powtec.2006.08.024

✦ Synopsis

In developing his powder classification, Geldart [D. Geldart, Powder Technol. 7 (1973) 285.] employed fluidization data obtained only at ambient temperature and pressure and from beds fluidized only with air. Unfortunately, industrial applications of fluidized bed technology invariably are at elevated pressure and temperature and with fluidizing gas other than air. Geldart classification of powders does not apply at elevated pressure and temperature. There are ample evidences reported in the literature indicating that normally Geldart Group B powders at ambient conditions, such as polymer particles, can behave like a Group A powder under polymerization conditions at elevated pressure and moderate temperature with substantial emulsion-phase expansion, relatively small bubbles, smooth fluidization, and reduced gas bypassing [