Abstract: Sucrose is classified as a strategic national reserve resource. As a foodstuff, it rapidly supplies the energy required by the human body, while also serving as a vital industrial raw material. Within the industrial production of sucrose, the crystallisation process constitutes a core stage of sugar manufacturing. By adjusting the addition of seed crystals, the concentration of the sugar solution, the system temperature, and the stirring rate, it is possible to achieve an ideal crystal morphology and particle size distribution. This, in turn, enhances the quality and yield of the final product. Research into the crystallisation characteristics and kinetics of sucrose is of significant importance for improving the efficiency of industrial sugar production, reducing energy consumption, and enhancing product quality. The unique properties of sucrose solutions, such as high viscosity and poor conductivity, limit characterisation methods during crystallisation. Traditional offline sampling techniques struggle to monitor particle changes in real time. However, focused beam reflectance measurement (FBRM) enables direct immersion of the probe into the sugar solution environment to record particle chord length distributions, facilitating real-time monitoring of the crystallisation process. This study employed FBRM for on-line monitoring of sucrose crystallisation. The nucleation process was initiated by adding seed crystals to a low-supersaturated sucrose solution. Real-time recording of variations in sucrose particle chord length distributions during crystallisation was conducted to investigate the effects of varying seed crystal addition amounts, temperatures, supersaturation levels, and stirring speeds on sucrose crystallisation. Statistical analysis of the sucrose particle chord length distribution yielded crystallisation kinetics data, including nucleation and growth rates under specific conditions. These data were fitted to a secondary nucleation empirical equation, thereby enhancing the fundamental dataset for sucrose crystallisation and providing a theoretical foundation for optimising industrial production processes.

Key words: sucrose, FBRM, chord length distribution, crystallisation kinetics, secondary nucleation empirical formula

摘要： 蔗糖属于国家战略储备资源，作为食物能够快速提供人体所需的能量，同时也是重要的工业原料之一。在蔗糖的工业生产过程中，蔗糖结晶工序属于制糖的核心环节，通过调节晶种添加量、糖液浓度、体系温度及搅拌速率，可得到理想的晶体形貌、粒径分布，进而提高最终产品的质量和产量。研究蔗糖结晶特性及结晶动力学对提高工业制糖效率、降低能耗、提高产品质量有着重要意义。由于蔗糖溶液具有黏度高、导电性差等性质，因此蔗糖结晶过程中的表征手段有限，传统离线取样检测方法难以实时监测过程中颗粒的变化，而聚焦光束反射测量技术(FBRM)能够直接将探头浸入糖液环境中记录颗粒的弦长分布，实现蔗糖结晶过程的实时监测。本工作使用FBRM在线监测了蔗糖的结晶过程，起晶操作是向低过饱和度蔗糖溶液中加入晶种，以此诱发结晶过程，实时记录结晶过程中蔗糖颗粒的弦长分布变化，研究不同晶种添加量、温度、过饱和度及搅拌速率对蔗糖结晶的影响。本工作统计并分析了蔗糖颗粒的弦长分布变化数据，得到特定条件下的晶体成核率和晶体生长率等结晶动力学数据，并将结晶动力学数据拟合出二次成核经验式，完善了蔗糖结晶的基础数据，为蔗糖工业生产优化提供理论基础。

关键词: 蔗糖, FBRM, 弦长分布, 结晶动力学, 二次成核经验式