间歇蒸馏的优化操作

本文研究了间歇蒸馏操作的最佳经济收益问题.在二元物系的系统模型中考虑了塔板的持液及冷凝器的持液,并考虑了塔板效率.用多项式拟合相平衡关系.选择回流比作为控制函数,应用最优控制理论导出计算步骤,用数值方法叠代出使经济收益函数最大的回流比函数.将解出的最优操作方案与两种传统的操作方案进行了比较.为检验最优操作方案的可实施性,在一筛板塔上进行了实验,证明优于传统操作.

Optimal Operation of Batch Distillation

The maximum profit policy in the operation of a batch distillation column separating a binary mixture has been studied. A generalized mathematical model was derived with consideration of tray efficiency and liquid hold-up in the plates and the condenser. The optimal scheme of reflux control was worked out by a digital method. Computation showed that the proposed optimal control scheme could lead to much higher profit than the conventional mode of operation using constant reflux ratio or constant overhead composition. To demonstrate the practical usefulness of the proposed scheme, experimental work was conducted for the separation of ethanol-water mixture in a 0.17 meter diameter batch distillation column which was operated both under the optimal reflux control scheme and according to the conventional mode of constant reflux ratio. The economic profit obtained from the former operation was found to be 207% higher than that from the latter, the theoretically predicted value being 220%.