Liquid–Liquid Dispersion and Selectivity of Chemical Reactions in the Inline Teethed High Shear Mixers

Abstract

The effects of various structural and operating parameters on liquid–liquid dispersion and selectivity of chemical reactions in inline single-row teethed high shear mixers (HSMs) were studied by a parallel competitive reaction system. The product distribution X S was applied to evaluate the mass transfer characteristics. The results show that X S decreases evidently at first in tandem with a slight increase as the rotor speed and flow rate rise. The results also indicate that the structural parameters of the rotors play a more important role in enhancing the mass transfer efficiency at higher rotor speed. Compared with adjusting other structural parameters, increasing the teeth number of the rotor can most significantly decrease both X S and Sauter mean drop size d 32. Computational fluid dynamics was applied to predict the flow and power characteristics. Furthermore, a dimensionless correlation for X S is established to provide references for the design and optimization of inline HSMs in liquid–liquid systems.

Novel Rotor-Stator Assembly Promotes the Emulsification Performance in an Inline High-Shear Mixer

“…As shown in Figure a, there is a significant circulating flow in the center of the toothed rotor at N = 12 000 rpm, which enhances the collision between the two phases and thus the turbulence in the mixer. Such backflow appears stronger at higher rotor speeds and may contribute to the larger span of RT-ST. There is also an obvious circulation loop between the stator teeth.…”

“…The SIMPLE algorithm is used to solve pressure-linked equations . In all cases, the ratio of the time step to the rotor revolution period is 1:200 . The convergence criteria is all the total normalized residuals below 10 –4 .…”

“…Emulsification processes have been used in a wide range of industries such as pharmaceuticals, cosmetics, and food, etc. − and have been involved in various unit operations such as extraction, chemical reactions, polymerization, and so on. − The average droplet size and droplet size distribution (DSD) of the products are pivotal parameters to evaluate the emulsion performance, owing to the significant effects on the available area of mass transfer, the stability, and the rheology. , …”

Evaluation on Micromixing of a Continuous Solid Particle Flow in In-Line HSMs by Experiments and Artificial Intelligence Approaches

“…Similarly, Jasińska et al , suggested that the backmixing of the reaction solution into the feed area of the feed pipe increased X s under a high rotor tip speed. Thus, the aggravation of backmixing with increasing the rotor tip speed led to the deterioration of micromixing . Therefore, at a low rotor tip speed, the effect of increasing the turbulent kinetic energy dissipation rate on improving micromixing was greater than the side effect of increasing backmixing, consequently resulting in the improvement of the micromixing.…”

“…Thus, the aggravation of backmixing with increasing the rotor tip speed led to the deterioration of micromixing. 50 Therefore, at a low rotor tip speed, the effect of increasing the turbulent kinetic energy dissipation rate on improving micromixing was greater than the side effect of increasing backmixing, consequently resulting in the improvement of the micromixing. However, the side effect of backmixing became serious with increasing the rotor tip speed, which weakened this strengthening effect on the micromixing.…”