KNO_3-H_2O溶液间歇结晶动力学

KINETIC PARAMETERS OF KNO_3 IN WATER FOR BATCH CRYSTALLIZATION PROCESS

基于ΔL定律推导了晶体线性生长速率的数学表达式 ,利用已建立的溶液间歇结晶动力学实验研究手段实现了溶液透光率和浓度的在线测量 .利用经验模型关联线性生长速率和相对过饱和度求取了生长动力学参数 ,并与文献值进行了比较 .结果发现 :对于自发成核结晶过程 ,综合动态透光率、过饱和度和经验模型可对成核和生长阶段进行定性识别 .

Based on the population balance model and AL law, a crystal growth rate equation was deduced, and an apparatus was built up and used to measure the on-line dynamic transmittance and concentration for the batch cooling crystallization process. The KNO3 in water was tested and its linear growth rate was also calculated with dynamic transmittance and concentration. When crystal growth was dominant in the later stage of crystallization, the KNO3 crystal growth kinetic parameters (kg and g) in the empirical model were obtained by correlating its linear growth rate with the relative supersaturation, and agreed well with those in the literature. For the spontaneous crystallization process, the nucleation and crystal growth stages could be identified qualitatively with the dynamic transmittance, supersaturation and the deduced linear growth rate equation. The growth rate equation and its solution in this paper would be further used for mechanism demonstrations and/or applications of the batch crystallization.