Rotary kiln transport processes

✍ Scribed by John R. Ferron; Dilip K. Singh

• Book ID: 102696173
• Publisher: American Institute of Chemical Engineers
• Year: 1991
• Tongue: English
• Weight: 1021 KB
• Volume: 37
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690370512

✦ Synopsis

Slow rotation of a cylindrical kiln, partially filled with powder or granular solid, produces a planar interface between the bulk of the solid and the gas phase, tilted at the angle of repose. Particles cascade downward on this plane, moving relatively freely and randomly, prouiding the principal mechanism for particulate diffusion and mixing in the kiln. The plane is also the most favorable location for chemical reactions that require efficient gas-solid heat and mass transfer. Conservation equations are constructed forplanar and bulk regions, coupled by theparticulate exchange produced by rotation. Sample problems of mixing and heat exchange illustrate problem formulation and useful simplifications. A penetration model predicts wallto-bed heat transfer coefficients, leading to better agreement with experiment than is obtained when planar processes are omitted.

Top-Plane and Bulk-Phase Flows

Particle exchange rate

Prior studies have noted that movement of solid is quite regular both in axial flow and with rotation of the kiln. Packing