Hydrodynamics in downflow fluidized beds (1): Solids concentration profiles and pressure gradient distributions

H. Zhang, J. X. Zhu, M. A. Bergougnou

Research output: Journal PublicationArticlepeer-review

97 Citations (Scopus)


In a 9.3 m high and 0.10 m i.d. gas-solids downflow fluidized bed (downer), the radial distributions of the local solids holdups and the pressure gradients along the downer column were measured to characterize the local and overall gas-solid low structure, using a fiber optical solids concentration probe and a series of pressure transducers. Results show that the radial solids holdup distribution in a downer reactor is much more uniform than that in a riser. Although the operating conditions do largely affect the hydrodynamics in the downer reactor, many common similarities still exist in the gas-solids flow patterns with the variation of the operating conditions. For most of the conditions tested, the radial profile of solids holdup reaches its fully developed state within 3-8 m from the top entrance. On the other hand, particles are fully accelerated within 1-4 m. However, under certain conditions, the development section can extend to as long as the downer itself.

Original languageEnglish
Pages (from-to)5461-5470
Number of pages10
JournalChemical Engineering Science
Issue number22
Publication statusPublished - Nov 1999
Externally publishedYes


  • Downer reactor
  • Flow development
  • Fluidized bed
  • Gas-solids cocurrent downflow
  • Hydrodynamics

ASJC Scopus subject areas

  • Chemistry (all)
  • Chemical Engineering (all)
  • Industrial and Manufacturing Engineering


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