SLIDE 1
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agenda
motivation basic understanding coalescence modelling settler simulation
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Coalescence Modelling for Settler Design David Leleu, Andreas - - PowerPoint PPT Presentation
Coalescence Modelling for Settler Design David Leleu, Andreas - - PowerPoint PPT Presentation
Coalescence Modelling for Settler Design David Leleu, Andreas Pfennig dleleu@uliege.be Products, Environment, and Processes (PEPs) Department of Chemical Engineering Universit de Lige www.chemeng.uliege.be/Pfennig 1 agenda
SLIDE 2
SLIDE 3
gravity settler
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SLIDE 4
pilot-plant settler with internals
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SLIDE 5
stirring cell
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SLIDE 6
settling of dispersion
6 Henschke, 2002
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stirring-cell experiment
5 10 15 20 25 30 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18
stirring cell height in m time in s
sedimentation curve coalescence curve
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SLIDE 8
effect description influenced by frequency at which drops meet equipment type, fluid dynamics, holdup drops bounce at high relative velocity equipment type, fluid dynamics,
- perating conditions
time drops stay in contact, tcontact equipment type, fluid dynamics,
- perating conditions
characteristic time drops need to coalesce, tcoalescence material system, drop size
modelling coalescence of drops
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SLIDE 9
settling of dispersion
9 Henschke, 2002
SLIDE 10
close-packed zone
drops deformation film drainage
Arnaud Saint-Jalmes, 2006 10
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counterflow
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continuous flow droplets εΔh ΔPhydrostatic ΔPhydrodynamic v ΔPtotal = Δphydrostatic -ΔPhydrodynamic
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ReDrop (Representative Drop) simulation
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definition of the system
- material properties
- simulation parameters
time loop local holdup evaluated for each height element drop loop
- drop velocity
- update of the vertical position
- f each drop
- coalescence evaluation
SLIDE 13
iso-optical settling experiment
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SLIDE 14
experimental measurement of the holdup
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10 20 30 40 50 60 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18
time in s cell height in m
0.000 0.1250 0.2500 0.3750 0.5000 0.6250 0.7500 0.8750 1.000
measured hold up
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settling simulation
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20 40 60 80 100 120 20 40 60 80 100 120 140 160 180
time in s cell heigth in mm
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summary
consistent coalescence model calibrated setup for model validation simulation tool based on ReDrop model able to characterize settling
behavior for any system
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David Leleu, Andreas Pfennig dleleu@uliege.be Products, Environment, and Processes (PEPs) Department of Chemical Engineering Université de Liège www.chemeng.uliege.be/Pfennig
Coalescence Modelling for Settler Design
SLIDE 18
coalescence probability: fundamental
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pcoalescence,Coulaloglou&Tavlarides = exp − tcoalescence tcontact
Coulaloglou & Tavlarides, Chem. Eng. Sci., 1977
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coalescence probability: fundamental
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