A common objective of various crystallization procedures is to produce polymorphic pure crystals that have a narrow size distribution and a specific average crystal size. A cooling continuous slug-flow crystallizer with silicone oil as the continuous phase and with separate nucleation and growth zones is developed for glycine crystallization. A supersaturation of 1.5–2.75, residence times of 8 and 11 min, and two crystallizer configurations were utilized for crystal production. The crystallizer can produce crystals with an average crystal size ranging from 70 to 350 μm, with up to 83% yield. The residence time, feed concentration, and temperature of the nucleation and growth zones are the major operational parameters regulated to produce the desired crystals without the need for crystal seeding. Experimental and computational validation confirmed that increasing the temperature in the growth zone resulted in the formation of crystals with a narrow size distribution. Consistent and continuous operation for several hours was achieved using the crystallizer. Thus, pure α-glycine crystals of the desired crystal size with narrow size distribution can be produced continuously using the slug-flow crystallizer design presented in this study.

中文翻译：

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甘氨酸在双区连续段状流结晶器中结晶以改善晶体尺寸分布


各种结晶程序的共同目标是生产具有窄尺寸分布和特定平均晶体尺寸的多晶型纯晶体。开发了一种冷却连续段状流结晶器，以硅油为连续相，具有单独的成核区和生长区，用于甘氨酸结晶。采用 1.5–2.75 的过饱和度、8 和 11 分钟的停留时间以及两种结晶器配置进行晶体生产。该结晶器可以生产平均晶体尺寸为 70 至 350 μm 的晶体，收率高达 83%。成核区和生长区的停留时间、进料浓度和温度是调节的主要操作参数，无需晶体晶种即可生产所需的晶体。实验和计算验证证实，提高生长区的温度会导致形成尺寸分布较窄的晶体。使用结晶器实现了数小时的一致和连续运行。因此，使用本研究中提出的段状流结晶器设计可以连续生产所需晶体尺寸且尺寸分布窄的纯 α-甘氨酸晶体。