Gas‐solids flow structures in a novel circulating‐turbulent fluidized bed

In this article a novel circulating-turbulent fluidized bed (C-TFB) featured by high solids holdup and high gross solids circulation has been introduced and tested. The purpose of the new design was to integrate conventional circulating and turbulent fluidized beds into a unique high-density fluidization system for more efficient gas-solid contact and significantly reduced solids backmixing. The hydrodynamic characteristics of the C-TFB were analyzed in terms of differential pressure, solids concentration, particle velocity, and local solids flux distributions. An axial homogeneous flow structure was easily obtained with cross-sectional average solids volume concentrations higher than 0.25 throughout the entire C-TFB. At all measuring positions there was no net downflow of solids and a good gas-solid mixing was observed. © 2008 American Institute of Chemical Engineers AIChE J, 2008

[1]  John R. Grace,et al.  Further measurements of flow dynamics in a high-density circulating fluidized bed riser , 2000 .

[2]  Hsiaotao Bi,et al.  Flow behavior and regime transition in a high-density circulating fluidized bed riser , 2004 .

[3]  Yong Jin,et al.  The axial distribution of the cross-sectionally averaged voidage in fast fluidized beds , 1992 .

[4]  J. Grace,et al.  Hydrodynamics of gas-solid fluidization , 1995 .

[5]  X. Bi.  Gas and Solid Mixing in High-Density CFB Risers , 2004 .

[6]  T. S. Pugsley,et al.  Radial solid mass flux profiles in a high-suspension density circulating fluidized bed , 2002 .

[7]  Hsiaotao Bi,et al.  Gas dispersion in fast fluidization and dense suspension upflow , 1999 .

[8]  Jesse Zhu,et al.  Characterizing particle aggregates in a high-density and high-flux CFB riser , 2002 .

[9]  Hsiaotao Bi,et al.  Situating the high‐density circulating fluidized bed , 1999 .

[10]  R. J. Dry,et al.  Gas—solids contact efficiency in a high-velocity fluidised bed , 1987 .

[11]  John R. Grace,et al.  Reflections on turbulent fluidization and dense suspension upflow , 2000 .

[12]  H. Bi,et al.  A State-of-the-Art Review of Gas-Solid Turbulent Fluidization , 2000 .

[13]  Jam Hans Kuipers,et al.  Measurements of solids concentration and axial solids velocity in gas-solid two-phase flows. , 1996 .

[14]  Joachim Werther,et al.  SOLIDS CONCENTRATION AND VELOCITY PATTERNS IN CIRCULATING FLUIDIZED BEDS , 1988 .

[15]  John R. Grace,et al.  Characteristics of gas-fluidized beds in different flow regimes , 1999 .

[16]  Maria Laura Mastellone,et al.  The effect of particle size and density on solids distribution along the riser of a circulating fluidized bed , 1999 .

[17]  Maurice A. Bergougnou,et al.  A novel calibration procedure for a fiber optic solids concentration probe , 1998 .

[18]  Mooson Kwauk,et al.  The Dynamics of Fast Fluidization , 1980 .

[19]  Joachim Werther,et al.  A comparison of laser Doppler and single-fibre reflection probes for the measurement of the velocity of solids in a gas-solid circulating fluidized bed , 1996 .

[20]  Jesse Zhu,et al.  Particle velocity and flow development in a long and high-flux circulating fluidized bed riser , 2001 .

[21]  Hsiaotao Bi,et al.  Suspension densities in a high-density circulating fluidized bed riser , 1999 .

[22]  Cor M. van den Bleek,et al.  Chaotic behavior of gas‐solids flow in the riser of a laboratory‐scale circulating fluidized bed , 1997 .

[23]  Nobuyoshi Nakagawa,et al.  Distinction between upward and downward flows in circulating fluidized beds , 1995 .

[24]  Near-wall hydrodynamics in a scale-model circulating fluidized bed , 1999 .

[25]  Hsiaotao Bi,et al.  Introduction to Circulating Fluidized Beds , 1997 .

[26]  Jesse Zhu,et al.  Axial and radial solids distribution in a long and high‐flux CFB riser , 2001 .

[27]  Jesse Zhu,et al.  Distinctions between low density and high density circulating fluidized beds , 1995 .

[28]  Michel Y. Louge,et al.  Pressure and voidage gradients in vertical gas-solid risers , 1990 .

[29]  Hsiaotao Bi,et al.  Static instability analysis of circulating fluidized beds and concept of high‐density risers , 1993 .

[30]  Jamal Chaouki,et al.  Characterization of dynamic gas–solid distribution in fluidized beds , 2000 .