Gas dispersion in fast fluidization and dense suspension upflow

Liu Jinzhong, John R. Grace, Bi Hsiaotao, Hiroshi Morikawa, Zhu Jingxu

Research output: Journal PublicationArticlepeer-review

46 Citations (Scopus)


While gas dispersion has been determined in CFB risers operated at low solids fluxes, data are lacking with respect to the high-density conditions common in FCC risers and other catalytic processes. In this paper experimental results are reported showing gas residence time distributions obtained using helium tracer and FCC particles for a 76 mm diameter riser of height 5.6 m with net solids fluxes extending up to 480 kg/m2s. A radially non-uniform dispersion model is proposed and compard with the axially dispersed plug flow model to determine the gas dispersion coefficients. The results show that gas backmixing becomes small for dense suspension upflow conditions where there is no downflow of solids near the riser wall.

Original languageEnglish
Pages (from-to)5441-5449
Number of pages9
JournalChemical Engineering Science
Issue number22
Publication statusPublished - Nov 1999
Externally publishedYes


  • Axial dispersion
  • Circulating fluidized beds
  • Fluidization
  • Gas mixing
  • Residence time distribution
  • Suspensions

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering


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