Collisional viscosity of FCC particles in a CFB

Gidaspow, Dimitri; Huilin, Lu

doi:10.1002/aic.690420910

Cited by 104 publications

(84 citation statements)

References 13 publications

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“…A video made previously by Miller (1992) shows that in the dense regime of interest in this study the particles at the wall undergo a vigorous up and down motion. It is basically this random particle motion that we measured with our CCD camera and converted into granular temperature (Gidaspow and Huilin, 1996). From it we had obtained a collisional viscosity that matched Miller and Gidaspow's (1992) reported viscosity obtained from pressure dropradial particle velocity measurements.…”

Section: Iit Circulating Fluidized Bedmentioning

confidence: 81%

“…The bed material was 530 micron glass beads with a density of 2.5 gr/cm 3 . The Particle Image Velocimetry method described elsewhere (Gidaspow and Huilin, 1996) was used to measure the axial and tangential velocities of the particles. Figure 2 shows a typical streak line generated on the computer screen.…”

Section: Discussionmentioning

confidence: 99%

“…At the present time there is no way of accurately estimating the restitution coefficient. Hence the granular temperature was experimentally measured for FCC particles using a CCD camera and the equation of state for particles was constructed using the measured solids pressure and the radial distribution functions of statistical mechanics Huilin, 1996 &1998). The kinetic theory model clearly explains why fluidized beds are such good heat transfer devices.…”

Section: A Solids Viscosity and Kinetic Theory Modelsmentioning

confidence: 99%

“…Granular temperatures were measured in the IIT CFB using a CCD camera (Gidaspow and Huilin, 1996). The technique involves a measurement of particle velocity distribution, in principle similar to that obtained much earlier by Carlos and Richardson (1968) using a photographic method.…”

Section: Particle Sonic Velocitymentioning

confidence: 99%

“…Fluid Bed Viscosity. The viscosity of the glass beads in the mixture was obtained in two ways: 1. from a direct measurement of the viscosity by a Brookfield viscometer and 2. from the measurement of the random particle velocity using the equation Gidaspow and Huilin (1996) have shown that these two methods give the same value of the viscosity for 75 micron FCC particles in a riser. The same result holds here, since the large viscosity of the 800 micron beads exceeds the viscosity of water and air.…”

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confidence: 99%

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Computational and Experimental Modeling of Slurry Bubble Column Reactors

Lam¹,

Gamwo²,

Gidaspow³

2002

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The objective of this study was to develop a predictive experimentally verified computational fluid dynamics (CFD) model for gas-liquid-solid flow. A three dimensional transient computer code for the coupled Navier-Stokes equations for each phase was developed and is appended in this report. The principal input into the model is the viscosity of the particulate phase which was determined from a measurement of the random kinetic energy of the 800 micron glass beads and a Brookfield viscometer. The details are presented in the attached paper titled "CFD Simulation of Flow and Turbulence in a Slurry Bubble Column". This phase of the work is in press in a refereed journal (AIChE Journal, 2002) and was presented at the Fourth International Conference on Multiphase Flow (ICMF 2001) in New Orleans, May 27-June 1, 2001 (Paper No. 909).The computed time averaged particle velocities and concentrations agree with Particle Image Velocimetry (PIV) measurements of velocities and concentrations, obtained using a combination of gamma-ray and X-ray densitometers, in a slurry bubble column, operated in the bubbly-coalesced fluidization regime with continuos flow of water. Both the experiment and the simulation show a down-flow of particles in the center of the column and up-flow near the walls and nearly uniform particle concentration.Normal and shear Reynolds stresses were constructed from the computed instantaneous particle velocities. The PIV measurement and the simulation produced instantaneous particle velocities. The PIV measurement and the simulation produced similar nearly flat horizontal profiles of turbulent kinetic energy of particles. To better understand turbulence we studied fluidization in a liquid-solid bed. This work was also presented at the Fourth International Conference on Multiphase Flow (ICMF 2001, Paper No. 910).To understand turbulence in risers, measurements were done in the IIT riser with 530 micron glass beads using a PIV technique. This report summarizes the measurements and simulations completed so far. This work will continue under the sponsorship of the National Science Foundation and Dow Corning Corporation. This phase of the work is part of the DOE/Industry/University Multiphase Fluid Dynamics Research Consortium.Optimization of the LaPorte pilot plant reactor was attempted by rearranging the heat exchangers. The paper accepted for presentation at the Sixth World Congress of Chemical Engineering, Melbourne, Australia, September 23-27, 2001 is a part of this report.ii Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency therefor, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, pro...

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Section: Iit Circulating Fluidized Bedmentioning

confidence: 81%

Section: Discussionmentioning

confidence: 99%

Section: A Solids Viscosity and Kinetic Theory Modelsmentioning

confidence: 99%

Section: Particle Sonic Velocitymentioning

confidence: 99%

mentioning

confidence: 99%

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Computational and Experimental Modeling of Slurry Bubble Column Reactors

Lam¹,

Gamwo²,

Gidaspow³

2002

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Measurement of granular temperature and stresses in risers

2004

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A computational fluid dynamics design of a carbon dioxide sorption circulating fluidized bed

2010

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A kinetic theory based hydrodynamic model with experimentally determined sorption rates for reaction of CO 2 with K 2 CO 3 solid sorbent is used to design a compact circulating fluidized bed sorption-regeneration system for CO 2 removal from flue gases. Because of high solids fluxes, the sorber does not require internal or external cooling. The output is verified by computing the granular temperatures, particle viscosities, dispersion, and mass transfer coefficients. These properties agree with reported measurement values except the radial dispersion coefficients, which are much higher due to the larger bed diameter. With the solid sorbent prepared according to published information, the CO 2 removal percentage at the riser top is 69.16%. To improve the CO 2 removal, an effort is needed to develop a better sorbent or to simply lower the inlet gas velocity to operate in a denser mode, leading to a larger system. Also, the effect of temperature rise on the removal efficiency is investigated.

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Collisional viscosity of FCC particles in a CFB

Cited by 104 publications

References 13 publications

Computational and Experimental Modeling of Slurry Bubble Column Reactors

Computational and Experimental Modeling of Slurry Bubble Column Reactors

Measurement of granular temperature and stresses in risers

A computational fluid dynamics design of a carbon dioxide sorption circulating fluidized bed

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