Abstract
Sandwich packings represent new separation column internals, with a potential to intensify mass transfer. They comprise two conventional structured packings with different specific geometrical surface areas. In this work, the complex fluid dynamics in sandwich packings is modeled using a novel approach based on a one-dimensional, steady momentum balance of the liquid and gas phases. The interactions between the three present phases (gas, liquid, and solid) are considered by closures incorporated into the momentum balance. The formulation of these closures is derived from two fluid-dynamic analogies for the film and froth flow patterns. The adjustable parameters in the closures are regressed for the film flow using dry pressure drop measurements and liquid hold-up data in trickle flow conditions. For the froth flow, the tuning parameters are fitted to overall pressure drop measurements and local liquid hold-up data acquired from ultra-fast X-ray tomography (UFXCT). The model predicts liquid hold-up and pressure drop data with an average relative deviation of 16.4 % and 19 %, respectively. Compared to previous fluid dynamic models for sandwich packings, the number of adjustable parameters could be reduced while maintaining comparable accuracy.
Funding source: Deutsche Forschungsgemeinschaft
Award Identifier / Grant number: KE 837/26-3, HA 3088/10-3
Acknowledgments
The authors are grateful to the Deutsche Forschungsgemeinschaft (DFG) for financial support. Furthermore, the comprehensive discussions with Prof. Faical Larachi and Dr. Ion Iliuta from Laval University are highly appreciated.
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Research ethics: Not applicable.
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Author contributions: Patrick Franke: Conceptualization, Methodology, Software, Validation, Writing – Original Draft, Iman Shabanilemraski: Conceptualization, Markus Schubert: Supervision, Uwe Hampel: Supervision, Eugeny Kenig: Conceptualization, Writing – Review & Editing, Supervision, The author(s) have accepted responsibility for the entire content of this manuscript and approved its submission.
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Competing interests: The authors state no conflict of interest.
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Research funding: Deutsche Forschungsgemeinschaft (DFG) (research project KE 837/26-3, HA 3088/10-3).
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Data availability: Not applicable.
Nomenclature
- Symbols
- a
-
specific surface area [m2 m−3]
- Bo
-
Bond number [–]
- d
-
diameter [m]
- E
-
Ergun constant [–]
- F
-
interaction force [N m−3]
- g
-
gravitational constant [m s−2]
- h
-
hold-up [m3 m−3]
- L
-
length [m]
- ∆p
-
pressure drop [mbar]
- ΔpH
-
specific pressure drop [mbar m-1]
- Re
-
Reynolds number [–]
- s
-
slit width [m]
- SPR
-
froth number [–]
- t
-
slit depth [m]
- u
-
superficial velocity [m s−1]
- v
-
interstitial velocity [m s−1]
- We
-
Weber number [–]
- w
-
slit width [m]
- z
-
vertical coordinate axis [m]
- Greek symbols
- α
-
angle [°]
- ε
-
void fraction [–]
- θ
-
inclination angle [°]
- η
-
viscosity [Pa s]
- ρ
-
density [kg m−3]
- σ
-
surface tension [N m−1]
- υ
-
volumetric fraction [m3 m−3]
- ψ
-
wetting efficiency [–]
- Subscripts
- C
-
column
- d
-
droplet
- G
-
gas
- L
-
liquid
- DC
-
downcomer
- DL
-
de-entrainment layer
- GL
-
gas-liquid
- GS
-
gas-solid
- LS
-
liquid-solid
- HL
-
hold-up layer
- geo
-
geometrical
- spec
-
specific
- Superscripts
- conv
-
conventional
- eff
-
effective
- FP
-
flooding point
- LP
-
loading point
- sl
-
slit
- super
-
superimposed
- Abbreviations
- ARD
-
average relative deviation
- UFXCT
-
ultra-fast X-ray tomography
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