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Optimal design and operation of a Draft Tube Spouted Bed Reactor for a photocatalytic process David Follansbee , John Paccione, Lealon Martin. Environmental Division Fundamentals of Environmental Systems Engineering . Tuesday, November 6, 2007. Outline . Motivation for process
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David Follansbee, John Paccione, Lealon Martin
Fundamentals of Environmental
Tuesday, November 6, 2007
Motivation for process
Parameters and Problem statement
Conclusion and Future Work
Photocatalytic slurry reactors
Photocatalyst particle separation
Photocatalyst loading limitations
Photocatalytic fixed bed reactors
Cross sectional area limitations
Longer reactor length for increase throughput
High pressure drops
Mass transfer and kinetics are coupled
Photocatalyst coating of reactor walls
Cross sectional and mass transfer limitations
Decoupling of mass transfer from kinetics
Continual degradation of contaminant and regeneration of photocatalyst
Photocatalyst immobilized on large, dense particles
Clean water outlet
Dirty Water inlets
Counter current contact
Constant fluid properties
Costant particle size and density
Mass load :
Log mean concentration difference:
A.Y. Khan. Titanium dioxide coated activated carbon: Masters thesis, University of Florida, 2003.
V. Manousiouthakis and L. L. Martin. Computers & Chemical Engineering, 28(8):1237–1247, July 2004.
Mass flowrate of fluid:
Mass flow rate of particles:
Fluid-particle interphase drag coefficient:
Z.B. Grbavcic, R.V. Garic, D.V. Vukovic, D.E. Hadzismajlovic, H.Littman, M.H. Morgan, and S.D. Jovanovic. Powder Technology, 72(2):183–191, Oct. 1992.
Modeled as a PFR
Pseudo first order reaction
No mass transfer limitations
Mass flow rate:
Intensity (Lambert-Beer Law):
Reactive Red degradation
2 mm catalyst particles
TiO2/AC photocatalyst composites
Z.B. Grbavcic, R.V. Garic, D.V. Vukovic, D.E. Hadzismajlovic, H.Littman, M.H. Morgan, and S.D. Jovanovic. Hydrodynamic modeling of vertical liquid solids flow. Powder Technology, 72(2):183–191, Oct. 1992.
Adsorptive mass transfer rates
Contaminant degradation rates
The annular flowrate and inlet concentration
Height of annular bed is insensitive to change in mass flowrate.
Operating at a low mass flowrate (<0.1 kg/s) allows for the most robust performance.
For the test system of TiO2/AC UV cost is high
Motivates for optimization of catalyst properties
i.e. density, UV adsorption, and kinetics
Model must be experimentally validated
Specifically the kinetics and mass transfer models
Dr. Howard Littman
Dr. Joel Plawsky
Dr. David Dziewulski (DOH and SUNY school of Public health)
Martin Research Group
Department of Defense