CIESC Journal ›› 2010, Vol. 18 ›› Issue (1): 66-79.

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A New Strategy of Integrated Control and On-line Optimization on High-purity Distillation Process

吕文祥1,2, 朱鹰1,2, 黄德先1,2, 江永亨1,2, 金以慧1,2   

  1. 1. Department of Automation, Tsinghua University, Beijing 100084, China;
    2. Tsinghua National Laboratory for Information Science and Technology, Beijing 100084, China
  • 收稿日期:2009-03-17 修回日期:2009-12-24 出版日期:2010-02-28 发布日期:2010-12-30
  • 通讯作者: HUANG Dexian, E-mail: huangdx@tsinghua.edu.cn
  • 作者简介:
  • 基金资助:
    Supported by the National High Technology Research and Development Program of China(2007AA04Z193);the National Natural Science Foundation of China(60974008,60704032)

A New Strategy of Integrated Control and On-line Optimization on High-purity Distillation Process

LüWenxiang1,2, ZHU Ying1,2, HUANG Dexian1,2, JIANG Yongheng1,2, JIN Yihui1,2   

  1. 1. Department of Automation, Tsinghua University, Beijing 100084, China;
    2. Tsinghua National Laboratory for Information Science and Technology, Beijing 100084, China
  • Received:2009-03-17 Revised:2009-12-24 Online:2010-02-28 Published:2010-12-30
  • Supported by:
    Supported by the National High Technology Research and Development Program of China(2007AA04Z193);the National Natural Science Foundation of China(60974008,60704032)

摘要: For high-purity distillation processes,it is difficult to achieve a good direct product quality control using traditional proportional-integral-differential(PID)control or multivariable predictive control technique due to some difficulties,such as long response time,many un-measurable disturbances,and the reliability and precision issues of product quality soft-sensors.In this paper,based on the first principle analysis and dynamic simulation of a distillation process,a new predictive control scheme is proposed by using the split ratio of distillate flow rate to that of bottoms as an essential controlled variable.Correspondingly,a new strategy with integrated control and on-line optimization is developed,which consists of model predictive control of the split ratio,surrogate model based on radial basis function neural network for optimization,and modified differential evolution optimization algorithm. With the strategy,the process achieves its steady state quickly,so more profit can be obtained.The proposed strategy has been successfully applied to a gas separation plant for more than three years,which shows that the strategy is feasible and effective.

关键词: distillation process control, split ratio, surrogate model optimization, modified differential evolution

Abstract: For high-purity distillation processes,it is difficult to achieve a good direct product quality control using traditional proportional-integral-differential(PID)control or multivariable predictive control technique due to some difficulties,such as long response time,many un-measurable disturbances,and the reliability and precision issues of product quality soft-sensors.In this paper,based on the first principle analysis and dynamic simulation of a distillation process,a new predictive control scheme is proposed by using the split ratio of distillate flow rate to that of bottoms as an essential controlled variable.Correspondingly,a new strategy with integrated control and on-line optimization is developed,which consists of model predictive control of the split ratio,surrogate model based on radial basis function neural network for optimization,and modified differential evolution optimization algorithm. With the strategy,the process achieves its steady state quickly,so more profit can be obtained.The proposed strategy has been successfully applied to a gas separation plant for more than three years,which shows that the strategy is feasible and effective.

Key words: distillation process control, split ratio, surrogate model optimization, modified differential evolution