联立模块法对环氧乙烷生产过程的模拟

应用联立模块法的模拟策略,对多循环回路、多控制变量的乙烯氧化制环氧乙烷过程进行了稳态、操作型数学模拟。在Upadbye和Grens准则基础上,提出了同一断裂族中具体断裂流股的实用选择方法。通过适当地选择已知对应函数关系的一些流股作为断裂流股,使得待求的非线性方程组的维数大大降低,从而明显地减少了计算时间和所需的计算机内存空间。针对化工过程非线性强的特点,采用了一种交替使用离散牛顿法和拟牛顿法,作为一维不完全搜索的非线性方程组的求解方法。一维搜索使用新的初始步长限制方法。系统模拟计算表明,这种算法是成功的,计算结果与生产实际相符。

Simulation of Ethylene Oxide Production Process with Simultaneous-Modular Approach

The process of producing ethylene oxide through ethylene oxidation is simulated by a operation-type steady flowsheeting technique with a simultaneous-modular approach. Based on Upadhye and Grens rule, a practical method of selecting some tear streams in the same tear group is presented. By choosing properly as tear ones some streams whose corresponding functional relationship is known, the number of dimensions of a system of nonlinear equations is sharply reduced; thus the computation time and storage requirement are decreased apparently. In accordance with the characteristic strong non-linearity of chemical processes, we present the algorithm in which the discrete Newton method and QuasiNewton method are used alternatively as the one-dimensional incomplete searching method to solve the system of non-linear equations. Meanwhile a new method of calculating initial step size in one-dimensional searching is suggested. The system simulation shows that the algorithm works well and the calculated results agree with the measured data.