Abstract: In the previous paper, a new plate-to-plate method was successfully used by the proper selection of iterative variables for performance prediction of ideal systems. In the present paper, similar method is used for calculating extractive distillation processes. The mole fraction of solvent in the bottom product XEB, as well as mole fraction ratios of components to be seperated on various plates vijs are selected as iteractive variables. An outer loop iteration and an inner loop iteration are involved in. The outer loop iteration is for the solvent. The mole fraction of solvent is calculated from the bottom upward and is matched at the top; XEB is then relaxed with the match tolerance. The inner loop iteration is for the components to be seperated. The subsequent set of vijs is calculated using the program proposed in the previous paper with ralative volatilities αijs obtained from the stagewise calculation. The inner loop iteration is carried out with fixed αijs and much less computer time is needed. The outer-loop consists of a single strong loop together with a number of comparatively insignificant ones. Therefore, this multivariable system is transferred into a single variable like system as mentioned in the previous paper.

摘要： 本文将萃取精馏模拟计算的迭代过程分解为外层萃取剂迭代和内层被分离组分迭代二个迭代过程.内层迭代无需调用热力学程序,因而只占用很少的计算时间.外层迭代回路由单一的强回路同若干弱回路组成,可以得到充分加速.通过这种分层迭代的方法使逐板计算法成功地应用于多元萃取精馏过程的操作型计算,获得了均匀快速的收敛.