EFFECT OF SOLIDS ON HOMOGENEOUS-HETEROGENEOUS FLOW REGIME TRANSITION IN BUBBLE COLUMNS

Experiments were conducted to study the effect of the presence of the solid phase on the homogeneous–heterogeneous flow regime transition in a bubble column 0.14 m diameter. Air, distilled water and calcium alginate beads (2.1 mm, 1023 kg/m 3 ) at concentrations c = 0–30% (vol.) were the phases. The basic data were the voidage–gas flow rate dependences. The critical point, where the homogeneous regime loses stability and the transition begins, was evaluated by the drift flux model. The critical values of voidage and gas flow rate were the quantitative measures of the homogeneous regime stability. These were plotted against the solid phase concentration. It was found, that both the voidage and the critical values increased with the solid content at low solid loading, approx. c = 0–3%, and decreased at higher loading, c> 3%. The homogeneous regime was thus first stabilized and then destabilized. To explain this dual effect, possible physical mechanisms of the solid phase influence on the uniform bubble bed were discussed. 2005 Elsevier Ltd. All rights reserved.

[1]  Liang-Shih Fan,et al.  Fundamentals of gas‐liquid‐solid fluidization , 1985 .

[2]  Liang-Shih Fan,et al.  Bubble wake dynamics in liquids and liquid-solid suspensions , 1990 .

[3]  R. Krishna,et al.  Flow regime transition in bubble columns , 1999 .

[4]  R. S. Douek,et al.  Hydrodynamics of vertical co-current gas-liquid-solid flows , 1997 .

[5]  N. Cheng,et al.  Exponential formula for computing effective viscosity. , 2003 .

[6]  James A. Finch,et al.  Effect of solid particles on gas holdup in flotation columns—II. Investigation of mechanisms of gas holdup reduction in presence of solids , 1995 .

[7]  Wen Jianping,et al.  Local hydrodynamics in a gas-liquid-solid three-phase bubble column reactor , 1998 .

[8]  D. Guha,et al.  Suspension of solids in a bubbling liquid: Critical gas flow rates for complete suspension , 1964 .

[9]  Rajamani Krishna,et al.  A MODEL FOR GAS HOLDUP IN BUBBLE COLUMNS INCORPORATING THE INFLUENCE OF GAS DENSITY ON FLOW REGIME TRANSITIONS , 1991 .

[10]  Atsushi Tsutsumi,et al.  GAS-LIQUID MASS TRANSFER IN A THREE-PHASE REACTOR , 1993 .

[11]  S. Morooka,et al.  Axial distribution of solid holdup in bubble column for gas‐liquid‐solid systems , 1989 .

[12]  R. Krishna,et al.  Influence of gas density on the stability of homogeneous flow in bubble columns , 1993 .

[13]  Effect of bubble column dimensions on flow regime transition , 2001 .

[14]  B. G. Kelkar,et al.  Hydrodynamics and axial mixing in a three-phase bubble column , 1982 .

[15]  A. Liné,et al.  Stability analysis of a bubble column , 2001 .

[16]  N. H. Thomas,et al.  Homogeneous–heterogeneous regime transition in bubble columns , 2001 .

[17]  Liang-Shih Fan,et al.  High-pressure three-phase fluidization: Hydrodynamics and heat transfer , 1997 .

[18]  Jyeshtharaj B. Joshi,et al.  Effect of fine particles on gas hold-up in three-phase sparged reactors , 1990 .

[19]  Aniruddha B. Pandit,et al.  Three Phase Sparged Reactors — Some Design Aspects , 1984 .

[20]  A. Schumpe,et al.  Gas-liquid interfacial areas in a bubble column with suspended solids , 1984 .

[21]  Rajamani Krishna,et al.  Size, structure and dynamics of “large” bubbles in a two-dimensional slurry bubble column , 1996 .

[22]  O. Molerus,et al.  Principles of Flow in Disperse Systems , 1993 .

[23]  G. Wild,et al.  Hydrodynamics and mass transfer in a suspended solid bubble column with polydispersed high density particles , 1997 .

[24]  Rajamani Krishna,et al.  Analogous description of the hydrodynamics of gas-solid fluidized beds and bubble columns , 1993 .

[25]  Liang-Shih Fan,et al.  Bubble characteristics in three-phase systems used for pulp and paper processing , 1996 .

[26]  S. M. Ghiaasiaan,et al.  Flow regimes and gas holdup in paper pulp–water–gas three-phase slurry flow , 2003 .

[27]  M. Ityokumbul,et al.  Effect of fine solids and frother on gas hold-up and liquid mixing in a flotation column , 1995 .

[28]  L. Fan,et al.  On the rise velocity of bubbles in liquid-solid suspensions at elevated pressure and temperature , 1997 .

[29]  E. Barnea,et al.  A generalized approach to the fluid dynamics of particulate systems: Part 1. General correlation for fluidization and sedimentation in solid multiparticle systems , 1973 .

[30]  Liang-Shih Fan,et al.  Some aspects of high-pressure phenomena of bubbles in liquids and liquid–solid suspensions , 1999 .

[31]  Yasuo Kato,et al.  The Behavior of Suspended Solid Particles and Liquid in Bubble Columns (気液接触反応装置に関する研究) -- (気泡塔) , 1972 .

[32]  K. Koide,et al.  GAS HOLDUP AND VOLUMETRIC LIQUID-PHASE MASS TRANSFER COEFFICIENT IN SOLID-SUSPENDED BUBBLE COLUMNS , 1984 .

[33]  Koichi Terasaka,et al.  Behavior of bubble formation in suspended solution for an elevated pressure system , 1997 .

[34]  Aniruddha B. Pandit,et al.  Mass and heat transfer characteristics of three phase sparged reactors , 1986 .

[35]  P. Wilkinson,et al.  Design parameters estimation for scale‐up of high‐pressure bubble columns , 1992 .

[36]  František Kaštánek,et al.  Chemical reactors for gas-liquid systems , 1992 .

[37]  Dennis N. Smith,et al.  Dispersed solid dynamics in a slurry bubble column , 1985 .

[38]  G. Wallis.  One Dimensional Two-Phase Flow , 1969 .

[39]  H. Müller-Steinhagen,et al.  Effect of solid particles on gas hold‐up in bubble columns , 1991 .

[40]  H. Kumazawa,et al.  Gas holdup and mass-transfer characteristics in a three-phase bubble column , 1986 .

[41]  Shigeo Uchida,et al.  Flow structure and phase distributions in a slurry bubble column , 1997 .

[42]  James A. Finch,et al.  Effect of solid particles on gas holdup in flotation columns—I. Measurement , 1995 .

[43]  David G. Thomas.  Transport characteristics of suspension: VIII. A note on the viscosity of Newtonian suspensions of uniform spherical particles , 1965 .

[44]  Chun-Min Chang,et al.  Liquid velocity and gas holdup in three-phase internal loop airlift reactors with low-density particles , 1995 .

[45]  R. Worden,et al.  The effects of solids density and void fraction on the bubble rise velocity in a liquid-solid fluidized bed , 1992 .

[46]  Jyeshtharaj B. Joshi,et al.  CRITERIA FOR THE TRANSITION FROM THE HOMOGENEOUS TO THE HETEROGENEOUS REGIME IN TWO-DIMENSIONAL BUBBLE COLUMN REACTORS , 1992 .

[47]  M. Ruzicka,et al.  Buoyancy-driven instability of bubbly layers: analogy with thermal convection , 2003 .

[48]  Liang-Shih Fan,et al.  Single bubble formation in high pressure liquid—solid suspensions , 1998 .

[49]  John R. Grace,et al.  Flow regime identification in gas-liquid flow and three-phase fluidized beds , 1997 .

[50]  J. Drahoš,et al.  Effect of viscosity on homogeneous-heterogeneous flow regime transition in bubble columns , 2003 .

[51]  K. N. Clark.  The effect of high pressure and temperature on phase distributions in a bubble column , 1990 .

[52]  Robert W. Field,et al.  Bubble Column Reactors , 1991 .

[53]  M. Fialová,et al.  Duality of the gas-liquid flow regimes in bubble column reactors , 1997 .

[54]  Yatish T. Shah,et al.  Gas-liquid-solid reactor design , 1979 .

[55]  H. Kumazawa,et al.  Influences of suspended fine particles on gas holdup and mass transfer characteristics in a slurry bubble column , 1986 .

[56]  D. Scott,et al.  The role of gas phase momentum in determining gas holdup and hydrodynamic flow regimes in bubble column operations , 1994 .

[57]  R. Krishna,et al.  Gas holdup in slurry bubble columns: Effect of column diameter and slurry concentrations , 1997 .

[58]  Liang-Shih Fan,et al.  Suspension viscosity and bubble rise velocity in liquid-solid fluidized beds , 1997 .

[59]  Jyeshtharaj B. Joshi,et al.  Hydrodynamic stability of multiphase reactors , 2001 .

[60]  Maurice A. Bergougnou,et al.  Hydrodynamic behavior of slurry bubble column at high solids concentrations , 1999 .

[61]  B. G. Kelkar,et al.  Hydrodynamics and axial mixing in a three-phase bubble column. Effects of slurry properties , 1984 .