Design and Evaluation of a Mesoscale Segmented Flow Reactor (KRAIC)

Abstract

The design and development of a mesoscale flow reactor is presented, together with initial performance evaluation. The custom-designed KRAIC (kinetically regulated automated input crystallizer) uses liquid-segmented flow to achieve plug flow and mixing throughout the reactor length while helping prevent encrustation issues experienced by other precipitation reactors and crystallizers. Evaluation of the reactor for production of solid-state particle products has been carried out using cooling crystallization of fast growing succinic acid to explore the potential of the KRAIC design to mediate blocking caused during the precipitation process. The segmented flow environment is successful in preventing encrustation during an unseeded 2 h cooling crystallization experiment.

Continuous Generation of Millimeter-Sized Glycine Crystals in Non-Seeded Millifluidic Slug Flow

“…Continuous crystallization has received increasing research interests in both academia and industry for controlling crystal qualities, including polymorphic form, size, and morphology [1][2][3][4][5][6][7][8][9][10][11][12][13]. Many types of continuous crystallizers have been designed to meet different product quality requirements, with representative examples: (a) multi-stage mixed-suspension mixed-product removal (MSMPR) crystallizers [14][15][16][17]; (b) fluidized bed crystallizers [18][19][20][21][22]; (c) oscillatory baffled crystallizers [23][24][25]; (d) unbaffled crystallizers with an interior tubing mixing enhancer [8] (such as static mixers [11,26,27]); and (e) segmented/slug-flow crystallizers [3,[26][27][28][29]. Stirred-tank based crystallizers (a) allow relatively longer residence time and spacious crystallization area.…”

Is zeroth order crystal structure prediction (CSP_0) coming to maturity? What should we aim for in an ideal crystal structure prediction code?

“…Perhaps g succinic acid will be found again, and it is in the CSD as a challenge to anyone who can design a method of nding it. The high-temperature a phase of succinic acid was once considered elusive at normal temperatures, but has been found as a contaminant aer grinding 44,45 and in liquid-(but not air-) segmented ow crystallisation 46 or by spray-drying from water. 47 This suggests that the a polymorph is observed when it forms rst and there has not been sufficient time for the solvent mediated transformation to b.…”

In situ non-invasive Raman spectroscopic characterisation of succinic acid polymorphism during segmented flow crystallisation

“…In situ crystallisation of SA in the KRAIC-R Succinic acid (1.01 M solution in water) was crystallised in a KRAIC set-up, under segmented flow conditions with a cooling gradient of 40-20°C over the 15 m length of the FEP tubing (1/8″ ID) as described in our previous work. 23 Flow rates and pump types employed are the same as those quoted in the slurry delivery section.…”