Liquid-liquid extraction intensification by micro-droplet rotation in a hydrocyclone

Abstract

The previous literature reports that using a hydrocyclone as an extractor intensifies the mass transfer and largely reduces the consumption of extractant from 1800–2000 kg h−1 to 30–90 kg h−1. However, the intensification mechanism has not been clear. This paper presents experimental and numerical methods to study the multi-scale motion of particles in hydrocyclones. In addition to the usually considered translational behavior, the high-speed rotation of dispersed micro-spheres caused by the anisotropic swirling shear flow is determined. The rotation speeds of the tested micro-spheres are above 1000 rad s−1, which are much larger than the instantaneous rotation speed in isotropic turbulence. Due to the conical structure of a hydrocyclone, the rotation speed maintains stability along the axial direction. Numerical results show that the particle Reynolds number of micro-droplets in a hydrocyclone is equal to that in conventional extractors, but the particles have high rotation speeds of up to 10,000 rad s−1 and long mixing lengths of more than 1000 mm. Both the rotation of micro-droplets along the spiral trajectories and the intense eddy diffusion in a hydrocyclone contribute to the extraction intensification.

Sustainability Challenges in Peptide Synthesis and Purification: From R&D to Production

“…A series of modifications of LLE have been developed over the years in order to maximize extraction efficiency and reduce solvent consumption and production costs. Relevant examples are liquid–liquid extraction in continuous flow system, , microdroplet rotation in a hydrocyclone, stirred/agitated extraction column and mixer settler . Nevertheless, these alternative LLE procedures have not been extensively applied to the synthesis of peptides or the results have not been published.…”

Soot elimination and heat recovery of industrial flue gas by heterogeneous condensation

“…5. In the cyclone separator, water molecules in the vapor collide combine with each other to form clusters under the action of a high-speed rotating gas flow field 29 . The high-speed rotating gas flow field can not only provide the centrifugal force for gas-solid separation, but also accelerate the self-rotation of particles.…”

Simultaneous Removal of SO2 and NO from the Flue Gas of Marine Ships with a Gas Cyclone–Liquid Jet Absorption Separator

“…When the high-speed flue gas flows into the GLAS, it impinges and breaks the injected liquid column into small droplets, which not only increases the mass transfer area but also increases the gas–liquid reaction rate. , The gas mixed with small droplets rotates in the GLAS at a high speed and produces a great centrifugal force field, which is much higher than the standard gravitational force field; it also forms a high-gravity field and enhances the mass transfer coefficient . In addition, the self-rotation and revolution of the droplets in the GLAS increase the update frequency of the droplet surface and finally increases the removal efficiency of NO and SO 2 . Then, the droplets that absorb SO 2 and NO are separated from the gas under the effect of the centrifugal force.…”