共沸精馏隔壁塔与萃取精馏隔壁塔的控制研究

Control of azeotropic dividing wall column and extractive dividing wall column

针对多元共沸物或近沸点混合物的分离,采用共沸精馏隔壁塔和萃取精馏隔壁塔两种流程,分别建立稳态模型,并进行了温度灵敏板的选择。针对共沸精馏隔壁塔建立若干两点温度控制结构,针对萃取精馏隔壁塔建立若干三点(及四点)温度控制结构。通过添加进料流量和组成扰动进行测试分析,分别为两种流程挑选了能有效抵抗进料扰动的温度控制结构。1共沸精馏隔壁塔最优控制结构:Q_(MC)/F控制TMC,13;Q_(RC)/F控制TRC,5。2萃取精馏隔壁塔最优控制结构:RRM控制TMC1,3;Q_r/F控制TMC1,12;RR_R控制TRC1,3;αv控制TMC1,9。最后通过分析两种最优控制结构的相似性,总结得出:带有再沸器与进料量比值(Q_r/F)控制的温度控制结构,可有效降低共沸精馏隔壁塔及萃取精馏隔壁塔体系的余差及超调量。

Azeotropic and extractive dividing wall column were used for the separation of multiple azeotrope mixture or closing-boiling mixture. Steady-state simulation of the two processes was established by Aspen Plus. The different matching relationships between manipulate variables and control variables were determined through the sensitive analysis of steady state relative gain. Then,some two-point temperature control structures for azeotropic dividing wall column while several three-point（or four-point） temperature control structures for extractive dividing wall column were proposed in Aspen Dynamics. After adding dynamic disturbance,it chose the best one for each process：（1） best control structure for azeotropic dividing wall column：Q（MC）/F control TMC,13,Q（RC）/F control TRC,5,and（2） best control structure for extractive dividing wall column： RRM control TMC1,3,Qr/F control TMC1,12,RRR control TRC1,3,αv control TMC1,9. Finally,through the analysis of the similarity of the best control structures,it showed that the control structure with the ratio of reboiler duty and mixture feed rate（Qr/F） can achieve reasonable control performance,which reduced the overshoot of product purities and residual error of these two systerms.