(339d) Separation Efficiency and Design Optimization of Gravity Settlers – CFD Modeling and Experimental Investigation

Separation
efficiency and design optimization of gravity settlers – CFD modeling and
experimental investigation

E.
Charlafti¹, J.
Steinhoff², D. Leleu³, L. Reinecke⁴, A.
Pfennig³, H. -J. Bart², M. Kraume¹

¹TU
Berlin, Berlin, Germany, ²TU Kaiserslautern, Kaiserslautern, Germany,
³Université de Liège, Liège,
Belgium, ⁴Franken Filtertechnik KG, Hürth,
Germany

The separation of two-phase liquid/liquid dispersions through
gravity settlers is a fundamental and widely implemented process, thanks to its
simplicity and its cost and energy efficiency. The joint research project
ERICAA (‘Energy and resources saving
through innovative and CFD-based design of liquid/liquid gravity separators’),
funded by BMWi (Federal Ministry for Economic Affairs
and Energy), aims to optimize design standards for gravity settlers used
for industrial liquid/liquid separation applications.

The experimental approach of the project is based on a
continuous mixer-settler setup, where the separation of paraffin oil-in-water dispersions
is monitored. The separation efficiency is determined through precise measurements
of the dispersed phase at the inlet and outlet of a standard DN150 gravity settler.
In parallel to the continuous separation process, batch settling experiments
are carried out with the help of an inline calibration device, which provides
complementary data on the optimal residence time in the continuous settler, as
well as on the dispersion characteristics^[1].

Numerical
simulations of the DN150 gravity settler based on computational fluid dynamics (CFD) are performed, not only to predict the separation
efficiency of the continuous process in a more

cost-sustainable
way, but also to generate additional information about parameters which are not
easily measurable, such as the velocity field inside the vessel. The results of
the CFD simulations are compared to the experimental results and their validation
is discussed.