On Liquid Flow Maldistribution through Investigation of Random Open-Structure Packings
Abstract
:1. Introduction
2. Materials and Methods
3. Results and Discussion
3.1. Uniform Initial Liquid Distribution
3.2. Peripheral Initial Liquid Distribution
3.3. Evaluation of the Liquid Radial Maldistribution
- 1.
- The maldistribution factor depends strongly on the liquid load and decreases with the increase in liquid load at low gas loads up to the loading point. On the contrary, at high gas loads above the loading point, the maldistribution increases with the increase in liquid load.
- 2.
- The maldistribution factor is almost independent of the gas load up to the loading point and it sharply increases with the further increase in the gas load to a maximal value in flooding conditions.
- 3.
- Below the loading point, the maldistribution slightly increases with the increase in packing height; however, after a certain height (above 2.5 m), it becomes constant and the liquid distribution assumes an equilibrium state. At gas loads above the loading point, the influence of the gas load is much stronger than that of the bed height and the data at different heights almost coincide.
4. Conclusions
- 1.
- In uniform initial irrigation, the liquid superficial velocity profiles in RSRP and RF are practically uniform in the column bulk and independent of the liquid load.
- 2.
- The relative wall flow in uniform initial distribution increases with the increase in nominal packing size, which leads to a higher value of the maldistribution factor. The relative wall flow and, consequently, the maldistribution factor decrease with the increase in liquid load except for a packed bed with a small height, where a small wall flow increase is observed in some packings.
- 3.
- The evaluation of the ability of the packings to return part of the wall flow in the column bulk in peripheral irrigation shows that the packings which retain more liquid in the wall flow are characterized by lower spreading capacity. The spreading capacity of the packing is independent of the liquid load and is evaluated by the spreading coefficients, calculated in point source initial distribution.
- 4.
- As expected, the large-scale liquid maldistribution in RSRP and RF is higher (Mf is two–three times higher) than in structured packings. However, there are operating conditions when Mf decreases close to the values of some structured packings.
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
Glossary
D | column diameter [m] |
Dr | liquid spreading coefficient [m] |
F0 | cross-section area of the column [m2] |
Fi | cross section area of the collection annulus i [m2] |
Fv | gas/vapor capacity factor [Pa0.5] |
h | axial coordinate [m] |
H | height of the packing layer [m] |
L0 | liquid load [m3m−2s−1] |
Li | local liquid superficial velocity in a collection annulus i [m3m−2s−1] |
Mf | liquid maldistribution factor [–] |
Q0 | total liquid flow rate [m3h−1] |
Qi | liquid flow rate in a collection annulus i [m3h−1] |
dimensionless radial cooridante, r = R/R0 [–] | |
R | radial coordinate [m] |
R0 | column radius [m] |
Ri | outer radius of a collection section [m] |
Abbreviations | |
CFD | Computational Fluid Dynamics |
IMTP | Intalox Metal Tower Packing |
RF | Ralu–Flow |
RMSR | Rauschert Metal Saddle Ring |
RSRM | metal Raschig Super-Ring |
RSRP | plastic Raschig Super-Ring |
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Collection Section | Ri [m] | Fi [m2] | |
---|---|---|---|
1 | 0.076 | 0.0181 | 10.5 |
2 | 0.105 | 0.0165 | 9.5 |
3 | 0.135 | 0.0226 | 13 |
4 | 0.165 | 0.0283 | 16.3 |
5 | 0.195 | 0.0339 | 19.6 |
6 | 0.230 | 0.0467 | 26.9 |
7 | 0.235 | 0.0730 | 4.2 |
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Dzhonova-Atanasova, D.; Stefanova, K.; Nakov, S. On Liquid Flow Maldistribution through Investigation of Random Open-Structure Packings. Designs 2023, 7, 47. https://doi.org/10.3390/designs7020047
Dzhonova-Atanasova D, Stefanova K, Nakov S. On Liquid Flow Maldistribution through Investigation of Random Open-Structure Packings. Designs. 2023; 7(2):47. https://doi.org/10.3390/designs7020047
Chicago/Turabian StyleDzhonova-Atanasova, Daniela, Konstantina Stefanova, and Svetoslav Nakov. 2023. "On Liquid Flow Maldistribution through Investigation of Random Open-Structure Packings" Designs 7, no. 2: 47. https://doi.org/10.3390/designs7020047