Experimental study of gas and particle behavior in the grid zone of a jetting fluidized bed cold model

The local behavior of gas and solids in a grid zone was investigated using a jetting fluidized bed cold model. Spherical alumina particles (440 μm, 1500 kg/m3) were used as bed material. A pair of optical fiber sensors, an AD converter and a personal computer were used to measure particle velocity in the jet, jet diameter and jet height. Tracer gas introduced from a center nozzle was sampled from various points in the grid zone and its concentration was measured by gas chromatography to investigate gas interchange between the jet and the annulus, and the gas dispersion in the annulus region. The effects of operational conditions, i.e., the shape of the gas distributor, nozzle diameter and gas flow rates, on the gas and particle behavior are discussed. It was considered that many more particles entered into the jet when a cone-shaped distributor rather than a flat distributor was employed. Employment of a narrower nozzle caused an increase in particle velocity at the bottom of the bed.

[1]  T. Mamuro,et al.  FLOW PATTERN OF FLUID IN SPOUTED BEDS , 1968 .

[2]  Takashi Akehata,et al.  A new method for evaluating the size of moving particles with a fiber optic probe , 1975 .

[3]  R. W. Lyczkowski,et al.  Hydrodynamics of fluidization in a semicircular bed with a jet , 1984 .

[4]  C. Wen,et al.  A generalized method for predicting the minimum fluidization velocity , 1966 .

[5]  Leo A. Behie,et al.  The grid region in a fluidized bed reactor , 1973 .

[6]  O. Levenspiel,et al.  Fluidization engineering, 2nd edition , 1991 .

[7]  N. Freychet,et al.  Gas transfer between a central jet and a large two-dimensional gas-fluidized bed , 1988 .

[8]  M. H. Morgan,et al.  Prediction of the maximum spoutable height and the average spout to inlet tube diameter ratio in spouted beds of spherical particles , 1979 .

[9]  Masayuki Horio,et al.  PARTICLE MOVEMENT ON A PERFORATED PLATE DISTRIBUTOR OF FLUIDIZED BED , 1980 .

[10]  T. Kojima,et al.  Development of numerical model for reactions in fluidized bed grid zone -application to chemical vapor deposition of polycrystalline silicon by monosilane pyrolysis- , 1990 .

[11]  Dimitri Gidaspow,et al.  Fluidization in Two-Dimensional Beds with a Jet. 2. Hydrodynamic Modeling , 1983 .

[12]  Masayuki Horio,et al.  GAS MOTION AND BUBBLE FORMATION AT THE DISTRIBUTOR OF A FLUIDIZED BED , 1990 .

[13]  Wen-Ching Yang,et al.  Estimating the Jet Penetration Depth of Multiple Vertical Grid Jets , 1979 .

[14]  Hugo S. Caram,et al.  Solid flow in the annular region of a spouted bed , 1989 .

[15]  Jam Hans Kuipers,et al.  Experimental and theoretical porosity profiles in a two-dimensional gas-fluidized bed with a central jet , 1992 .

[16]  W. B. Whiting,et al.  A technique for measurement of jet penetration in hot fluidized beds with a modified Pitot-tube probe , 1988 .