Longitudinal mixing in fluidization

✍ Scribed by E. J. Cairns; J. M. Prausnitz

• Book ID: 102692962
• Publisher: American Institute of Chemical Engineers
• Year: 1960
• Tongue: English
• Weight: 716 KB
• Volume: 6
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690060311

✦ Synopsis

Abstract

Longitudinal mixing properties in liquid‐solid fluidized beds were investigated by means of a salt‐solution tracer technique. The electrical conductance breakthrough curves were measured with very small electrical conductivity probes for a step‐function input of salt‐solution tracer. Longitudinal eddy diffusivities were determined for 1.3‐ and 3.0‐mm. lead spheres and 3.2‐mm. glass spheres in 2‐ and 4‐in.–diameter beds at a distance of 5 bed diam. from the injector and for various radial positions.

The longitudinal mixing properties are strongly affected by particle concentration; maximum mixing occurs at a fraction voids of 0.7. Longitudinal eddy diffusivity increases with particle density and with decreasing d~p~/D ratio. Velocity profiles markedly influence the eddy‐diffusivity profiles.