(258c) Evaluation of Novel Mixing and Separation Apparatus for Liquid-Liquid Extraction

Motivated by the recently developed spiral medium gravity separator [1], a novel integrated spiral device that combines mixing and separation for liquid-liquid extraction is conceived [2]. In the first section of the device, the flow path design is used for enhancing the mixing of immiscible liquid streams that have different densities. In the second section that immediately follows, separation of liquid phases is achieved by flow through spiral curved channels that separates liquid streams based on their densities. In the flow regimes considered, the centrifugal force dominates either to facilitate mixing or separation depending on the flow path design.

In the mixing section, heavier liquid phase is introduced near the inner side of the inlet and the lighter phase is introduced at the outer side of the inlet. As the liquid streams travel down the curvature of a spiral turn, due to the induced centrifugal force, the heavier phase penetrates through the lighter phase reaching the outer wall and vice-versa. The spiral turn is followed by a counter spiral turn that causes the phenomenon to repeat again enabling greater mixing and contact among the phases. Several such turns and counter turns could be stacked to form intensive mixing as necessary. Once the desired solute extraction is achieved, the second section of the integrated device achieves the phase separation with the help of unidirectional spiral turns. At the exit, the streams are cut into two (or more) fractions separating the phases.

A multiphase CFD model based on the VOF approach is employed to simulate the flow inside the novel device. The assumed conditions are: the flow is steady, turbulent, and incompressible. The CFD simulations are carried out using ANSYS Fluent 16.0. Simulations confirm the expected flow patterns and predict much improved performance. A standard multi-phase multi-component system is chosen for studying the liquid-liquid extraction operation.

References:

[1] “PHASE SEPARATION APPARATUS AND METHOD" A Patent Application Filed at Indian Patent Office on 28 February, 2017. Application Number 201721006976 Inventors: Sivakumar Subramanian, Arjun Kumar Pukkella, and Raviraju Vysyaraju.

[2] “INTEGRATED APPARATUS FOR MIXING AND SEPARATING FLUID PHASES AND METHOD THEREFOR” A Patent Application Filed at Indian Patent Office on 14 March, 2018. Application Number 201822007888. Inventors: Arjun Kumar Pukkella, Sivakumar Subramanian and Raviraju Vysyaraju.