间歇结晶过程广泛应用于精细化工、医药、生物等过程,该过程的模拟将对产品质量和过程控制具有重要作用。本文建立了间歇结晶过程数学模型。该模型是一个包含双曲型偏微分方程(粒数衡算方程)及微分-积分方程的复杂方程组,其较强的非线性使得难以求得解析解。本文用数值方法计算了粒数密度分布函数、过饱和度、成核与生长速率等重要的过程参数,定义并计算了过程的产品质量评价指数。定量模拟了晶种对结晶过程的影响,以及结晶过程中成核和生长的竞争关系,同时,对上述现象和规律进行了理论分析。
Batch crystallization is widely used in fine chemicals, pharmacy and biological processes. The simulation of it is of importance to product quality and process control. A mathematical model for batch cooling crystallization is setup. The model is described by a set of integro-differential equations including a hyperbolic partial equation ( Population balance equation). Being strongly nonlinear, the problem does not possess an analytical solution. Numerical method is used to calculate process parameters such as the crystal density function, super saturation, nucleation rate and growth rate, and process product quality evaluation indices are defined and computed. The unseeded and seeded batch cooling crystallization processes are quantitatively simulated respectively to investigate the influence of crystal seeds. Competition between nucleation and growth in crystallization process is also simulated. Transient phenomena in these processes are given thorough explanation from theoretical aspect.