Abstract:

The design margin of chemical process is generally given by design experience or economic optimization. The design experience cannot guarantee the optimization of economic performance. And the economic optimization needs to solve a large-scale nonlinear optimization problem. The optimization calculation is often complicated for large-scale nonlinear optimization, and it is easy to fall into the local extreme point, and the design results sometimes is against the design experience. In this paper, the non-square relative gain array(NRGA) and the non-square relative energy gain array (NREGA) are used to describe the sensitivity relationship between independent variables and dependent variables in chemical process. The independent variables are divided into operation variables and design variables, and the dependent variables are divided into economic optimization variables and constraint variables. Because relative gain is dimensionless and normalized, operation variables and design variables can be prioritized according to the relative gains of economic optimization variables and constraint variables, and for process uncertainty, each operation variable and each design variable can be adjusted according to the priority. The margin design scheme can be found with the least impact on the process economic performance and the effectively moving of the operation point away from the constraint boundary. Finally, the series reactor is taken as an example to verify the design method. The results show that, compared with the margin design method for solving economic optimization problems, this design method obtains design results close to the economic performance, and the calculation is simple, and there is no need to solve the optimization problem.

Key words: process optimization, process design, design margin, relative gain, priority

摘要：

化工过程设计裕量一般是通过设计经验或经济优化给出的，设计经验无法保证经济性能的优化，而经济优化需要求解大规模非线性优化问题，计算复杂，容易陷入局部极值点，设计结果有时与设计经验违背。本文用非方相对增益阵和非方相对能量增益阵描述化工过程设计的自变量和因变量的灵敏度关系，将自变量划分为操作变量和设计变量，将因变量划分为经济指标和约束变量。相对增益具有无量纲化和归一化的优点，因此可根据经济指标和约束变量的相对增益对操作变量和设计变量划分优先级，针对过程不确定性的大小按照优先级依次调整各个操作变量和设计变量，找到对过程经济性能影响最小并有效移动操作点、远离约束边界的裕量设计方案。以串联反应釜为例对该设计方法进行了验证，结果表明，与求解经济最优化问题的裕量设计方法相比，本设计方法得到了经济性能与之接近的设计结果，计算简单，无须求解最优化问题。

关键词: 过程优化, 过程设计, 设计裕量, 相对增益, 优先级