Comparison of decoupling methods for analyzing pressure fluctuations in gas-fluidized beds

Authors

  • Yongmin Zhang,

    1. State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, P.R. China
    Search for more papers by this author
  • Hsiaotao T. Bi,

    Corresponding author
    1. Fluidization Research Centre, Dept. of Chemical and Biological Engineering, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
    • Fluidization Research Centre, Dept. of Chemical and Biological Engineering, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
    Search for more papers by this author
  • John R. Grace,

    1. Fluidization Research Centre, Dept. of Chemical and Biological Engineering, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
    Search for more papers by this author
  • Chunxi Lu

    1. State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, P.R. China
    Search for more papers by this author

Abstract

Two methods of decoupling pressure fluctuations in fluidized beds by using the incoherent part (IOP) of absolute pressure (AP) and differential pressure (DP) fluctuations are evaluated in this study. Analysis is conducted first to demonstrate their similarities, differences, and drawbacks. Then, amplitudes, power spectral densities, mean frequencies, coherence functions, and filtering indices of the IOP of AP and DP fluctuations are calculated and compared based on experimental data from a two-dimensional fluidized column of FCC particles. Derived bubble sizes are also compared with the sizes of bubbles viewed in the two-dimensional bed. The results demonstrate the similarity of these two methods in filtering out global compression wave components from absolute pressure fluctuations, especially those generated from oscillations of fluidized particles and gas flow rate fluctuations. However, both methods are imperfect. Neither can filter out all the compression wave components and retain all the useful bubble-related wave components. Their amplitudes can be used to characterize global bubble property and quality of gas–solids contacting in bed, but they do not give accurate measurement of bubble sizes. © 2009 American Institute of Chemical Engineers AIChE J, 2010

Ancillary