Multistage Crystallization of Plate-like Crystals: A Modeling and Experimental Study on Adipic Acid

Particles exhibiting a plate-like shape, encountered during crystallization, present challenges in downstream processing. Consequently, it is crucial to manipulate the size and shape of such populations. However, comprehensive studies addressing this issue are lacking due to the absence of monitoring tools capable of accurately characterizing the particle size and shape distribution (PSSD) systems with a complex morphology. Leveraging recent advancements in monitoring technology, this work investigates a multistage crystallization process, encompassing growth, wet milling, and dissolution, to modify the PSSD of plate-like crystals. Employing a combination of experimental and modeling approaches, with adipic acid in water as the system, the influence of key multistage process parameters on the PSSD and filtration performance is evaluated. A multidimensional population balance equation-based model is utilized to analyze the intricate interplay among growth, dissolution, and breakage kinetics. The findings demonstrate the efficacy of the multistage process in modifying the particle size and fines content and thereby reducing the filter cake resistance of the product, a key indicator of powder processability. The insights gained from this study will be instrumental in designing processes for manipulating the size and shape of crystalline powders, particularly exhibiting a complex morphology like the one studied here.