Tuning of Particle Size in a Helical Coil Reactor

Abstract

This study investigates the effect of initial reactant concentration, residence time, and flow on the particle size and particle size distribution produced by single-phase reactive precipitation between BaCl2 and Na2SO4 in a helical coil reactor. Helical coils offer enhanced mixing due to the secondary flow generated by the imbalance of centrifugal forces. The particles produced in a helical coil reactor are found to have smaller sizes and narrower size distribution compared to a straight tube reactor under similar process conditions. It is shown that the average particle size in a helical coil reactor decreases with increasing Dean number, and particle size distribution becomes narrower at higher Dean number. For a reactant concentration of 0.5 M with the reactant concentration ratio of one, the average size changed from 580 to 263 nm when Dean number changed from 64 to 370. The initial reactant concentration is defined in terms of supersaturation ratio, and a decreasing trend in size is also observed with increasing supersaturation ratio. The particle size distribution curve also became narrower at higher supersaturation ratio. The residence time is observed to have no visible effects on the particle mean size and particle size distribution for the range of residence time, from 6 to 34 s, studied for the helical coil in this work.

Continuous Antisolvent Crystallization Using Fluidic Devices: Fluidic Oscillator, Helical Coil, and Coiled Flow Inverter

“…These devices have been used as plug-flow crystallizers in continuous antisolvent crystallization. For example, Pal et al implemented reactive precipitation between BaCl 2 and Na 2 SO 4 using helical coils, and it was found that smaller particles can be produced using helical coils compared with straight tubes . Benitez-Chapa et al used CFIs to carry out continuous antisolvent crystallization of flufenamic acid, and it was found that the crystal mean size of the final product decreased as the number of 90° flow inverters increased .…”

“…For example, Pal et al implemented reactive precipitation between BaCl 2 and Na 2 SO 4 using helical coils, and it was found that smaller particles can be produced using helical coils compared with straight tubes. 15 Benitez-Chapa et al used CFIs to carry out continuous antisolvent crystallization of flufenamic acid, and it was found that the crystal mean size of the final product decreased as the number of 90°flow inverters increased. 16 Orehek et al (2022) utilized CFIs to implement multi-segment multi-addition continuous antisolvent crystallization of benzoic acid.…”

CFD Analysis of a Kenics Static Mixer with a Low Pressure Drop under Laminar Flow Conditions

“…Different static mixing elements and configurations − have been used to achieve fluid mixing depending on process requirements and pressure drop. Enhanced mixing in static mixers leads to improved heat transfer. ,, Furthermore, in crystallization studies, supersaturation gradients can be minimized with static mixers, which results in products with a narrower particle size distribution compared to devices without flow switching. − The ideal static mixer is one in which efficient mixing can be achieved with a low pressure drop.…”

3D investigations of microscale mixing in helically coiled capillaries

“…Investigating transport phenomena in helically coiled tubes is still of great interest [7,8,[21][22][23]. Especially non-invasive imaging approaches promise great insights and are crucial for the validation of numerical simulations [24].…”