Distinctions between low density and high density circulating fluidized beds

J. ‐X Zhu, H. ‐T Bi

Research output: Journal PublicationComment/debate

95 Citations (Scopus)


While many fundamental studies have been carried out in relatively low density circulating fluidized beds (LDCFB), there has been little reported fundamental study of the high density (including high solids flux and/or high solids concentration) circulating fluidized bed (HDCFB), although many commercial CFB setups are operating under high density conditions. Catalytic gas‐phase reactions tend to require higher gas velocity and higher solids flux and/or concentration than gas‐solids reactions, and therefore it is necessary to make a distinction between the two types of operations. The study of hydrodynamics and other fundamentals of HDCFB will help in understanding the fundamentals and thus improving the design and operation of existing HDCFB reactors such as FCC risers, and may also lead to other applications requiring even higher solids/gas feed ratios and/or higher solids concentration in the riser. On the other hand, high density operation can only be achieved by properly choosing the gas blower, solids feeding system and CFB geometry to avoid the instabilities resulting from insufficient pressure head from the gas blower and downcomers.

Original languageEnglish
Pages (from-to)644-649
Number of pages6
JournalCanadian Journal of Chemical Engineering
Issue number5
Publication statusPublished - Oct 1995
Externally publishedYes


  • CFBC
  • FCC
  • circulating fluidized bed
  • high density/high flux operation

ASJC Scopus subject areas

  • Chemical Engineering (all)


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