化工过程大范围工况变化的工况迁移控制策略判定

化工过程出现大范围的工况变化时,复杂的迁移控制策略会带来一定的操作不确定性,因此需要对控制策略进行选择判定。考虑到直接估计工况变化过程生产指标变化量带来的判定误差,引入了中间变量,提出了基于中间变量的控制策略选择判定方法,并分析给出了构建中间变量的基本准则。进而通过对某实际乙烯精馏塔工况变化过程的仿真研究,说明了中间变量的引入能够很大程度地降低对生产指标的估计误差,验证了基于中间变量的控制策略选择判定方法的可用性。

Judgement of process transition control strategies for large-range conditions change of chemical processes

When the chemical process changes in a wide range of working conditions, the complex migration control strategy will bring certain operational uncertainty, so it is necessary to make a selection decision on the control strategy. Intuitively, the simplest approach for the judgment of control strategies is mapping the relationship between the production index and the factors which cause the process transition. The fitting error of the mapping relationship is obvious for complicated chemical processes. The intermediate variables are introduced for decreasing fitting error, and intermediate variables based judgment method is proposed for complicated chemical processes. In details, there are three basic principles for building the intermediate variables. Firstly, the intermediate variables consist of measurable process variables; secondly, the intermediate variables are insensitive to the type of process transition factors; thirdly, the intermediate variables are sensitive to the production index of the process system. Furthermore, based on the simulation of a commercial ethylene column, the introduction of the intermediate variables is beneficial to decrease the estimation error of production index. The usability of the intermediate variables based judgment method is verified for the control of large-range conditions change.