Nonlinear Model Predictive Control Based on Wave Model of High-Purity Internal Thermally Coupled Distillation Columns

Abstract

Although the internal thermally coupled distillation column (ITCDIC) is much more energy-efficient than the conventional distillation column, the complex dynamics stemming from thermal coupling between the rectifying column and the stripping column have restrained the achievement of control strategies and application in chemical industry. To reduce the difficulties, a novel nonlinear wave model of ITCDIC process is proposed based on the wave theory in the separation processes to simplify the mechanism model of ITCDIC. A nonlinear model predictive control based on the proposed wave model (NWMPC) of the ITCDIC process is further established to handle the multivariable interactions and improve the control performance. A dynamic optimization scheme characterized by an improved control parametrization method is introduced to solve the problem generated by the NWMPC model. An IMC controller is also explored as a comparison research. In the example of a benzene–toluene system, NWMPC presents great advantage over IMC in the servo and regulatory control.

Trade‐off between energy consumption and ethylene recovery rate for quasi‐plant wide operation optimization of the ethylene column with bottom circulatory system in ethylene complex

“…Cong and Liu presented a new model-based control strategy for the internal thermally coupled distillation column based on nonlinear wave theory. [30,31] Furthermore, an improved instant wave velocity is first derived for the heat-integrated air separation column, and the advantages of the proposed generalized generic model control scheme are confirmed. [32] On the other hand, aberrant conditions frequently occur in commercial processes, and relevant research remains challenging and limited.…”

Nonlinear Wave‐Based Measurement Location Design and Online Estimation of a High‐Purity Heat‐Integrated Distillation Column

“…It has been proven that the linearized model could hardly handle the difficulties in high‐purity HIDiC 17, 18. So an appropriate nonlinear model of HIDiC is necessary for the development of the controller.…”

Nonlinear dynamic behaviors and control based on simulation of high-purity heat integrated air separation column

“…It can be seen that HIASC is more complicated than HIDiC. In a sense, HIASC is a special HIDiC, applied in a cryogenic air separation process with a three-component system, which is different from those HIDiCs with a two-component system in an open literature, such as the benzene-toluene system of HIDiC [19,42,46].…”