Local phase holdups in gas-solids fluidization and transport

✍ Scribed by Hsiaotao T. Bi; Peng-Cheng Su

• Publisher: American Institute of Chemical Engineers
• Year: 2001
• Tongue: English
• Weight: 197 KB
• Volume: 47
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690470913

✦ Synopsis

Abstract

A two‐phase structural model consisting of a dense phase and a dilute phase with allowance for the dense‐phase expansion and the solids holdup in the dilute phase was developed and successfully applied to the analysis of local voidage fluctuation signals. Such a model can be used to derive local‐phase holdups and voidage in each phase in both bubbling/slugging/turbulent fluidized beds and circulating fluidized‐bed risers without ambiguity in defining criteria for dividing phases used by previous researchers. Such a model can also explain the existence of a maximum standard deviation at a local voidage around 0.7, and why a maximum peak is observed in the radial profiles of standard deviation of local voidage fluctuations in high‐velocity fluidized‐bed columns.