CHAPTER 5. Slug-flow Continuous Crystallization: Fundamentals and Process Intensification

Author(s):  
J. Carl Pirkle ◽  
Michael L. Rasche ◽  
Richard D. Braatz ◽  
Mo Jiang
Symmetry ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2092
Author(s):  
Niclas von Vietinghoff ◽  
David Hellmann ◽  
Jan Priebe ◽  
David W. Agar

Segmented slug flow systems in capillaries have already shown good potential for process intensification, due to their symmetry in the characteristic flow pattern. However, several challenges remain in this technology. For instance, in gas-consuming reactions, like Aliq + Bgas→Cliq, the gas droplets shrink and may even disappear, limiting the conversions and throughputs of capillary reactor systems. To overcome such shortcomings, an intermediate gas feed was developed. In order to maintain the well-defined slug flow characteristics, it is necessary to introduce the gas rapidly and precisely, in small aliquots of <10 µL. This allows us to preserve the well-defined alternating triphasic slug flow. A miniaturized electrolysis cell, together with a flow-observing system, was thus devised and implemented successfully as an intermediate gas feed. Feeding a new gas droplet into an existing liquid–liquid segmented flow had a success rate of up to 99%, whereas refilling an existing gas droplet is often limited by a lack of coalescence. Here, only at low volumetric flows, 70% of the gas bubbles were refilled by coalescence.


Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1449
Author(s):  
Anoj Winston Gladius ◽  
Simon Höving ◽  
Mehdy Mendelawi ◽  
Harikrishna Sreekumar Sheeba ◽  
David W. Agar

Liquid–liquid slug flow in a microcapillary, with its improved heat and mass transfer properties and narrow residence time, plays a vital role in process intensification. Knowledge of the flow properties in microchannels along variables’ controllability (e.g., phase ratio, slug length along with classical variables, such as pressure, temperature, and flow velocity) during operation is crucial. This work aids in this by using magnetofluidics to manipulate these parameters. A ferrofluid with reproducible properties is produced and, together with another phase, stable slug flow is generated. Micro-gear pumps and syringe pumps, with their traditional mechanical components, result in parts degrading over time due to fatigue caused by pressure differentials and corrosive chemicals. The microflow is also disturbed by the invasive nature of these pumps. A considerably energy-efficient, non-invasive alternative, with reduced mechanical interfacing is suggested in this work. It uses magnetic gradients to manipulate two-phase flow, one of which is a magnetically active phase. Conveying concepts using permanent magnets in the immediate vicinity of the flow are investigated. To operate this pump continuously and to be able to regulate the phase ratio, an electromagnetic non-invasive valve is developed. Phase separation is also carried out with an existing decanter design, modified using electromagnetism to work without a selective membrane, usually necessary for phase separation at this scale. This pump is then compared with similar pumps developed in the past.


Author(s):  
Kenshiro Muramatsu ◽  
Youngjik Youn ◽  
Youngbae Han ◽  
Keishi Yokoyama ◽  
Yosuke Hasegawa ◽  
...  

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