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在化工分离过程设计中,共沸点预测的作用十分重要,目前常用的方法有牛顿迭代和牛顿同伦等,都需要求解大型非线性方程组,且牛顿迭代法易发散,本文提出修正UNIFAC模型的逐次代入法同时与折半搜索联合的算法,既克服牛顿迭代计算时因取初值不合适时而容易发散的缺点,又不需要求解大型非线性方程组,且计算速度快,计算中对逐次代入法进行改进,使温度初值的取法更简捷,且无发散现象,通过验证乙醇,苯等10多种二元混合物,计算过程均可在1MS以内完成,计算所得共沸点与文献所载实验值比较,平均误差<1%,共沸点组成与文献所载实验值比较,平均误差<2%,证明该法不但可用于二元混合物共沸点预测,又可在相应大型数据库中查找可产生共沸效果的混合物。
In the design of chemical separation process, the effect of azeotropic point prediction is very important. At present, the commonly used methods are Newton iteration and Newton homotopy, which all need to solve large-scale nonlinear equations and the Newton iteration method is easy to diverge. In this paper, we propose a modified UNIFAC model Successive substitution method and binary search combined algorithm, both to overcome the Newton iterative calculation due to improper initial time and easily divergent shortcomings, but also do not need to solve large-scale nonlinear equations, and the calculation speed, the calculation of successive substitution method The initial value of temperature is more simple and has no divergence. Through verifying more than 10 binary mixtures such as ethanol and benzene, the calculation process can be completed within 1MS. The calculated azeotropic point is in good agreement with the experimental data in the literature , The average error is less than 1%, the average boiling point is less than 2%, the average error is less than 2%, which proves that this method can not only be used to predict azeotropic boiling point of binary mixtures, but also can find azeotropic effect in the corresponding large database mixture.