Design and Implementation of Decoupling Controller of Wood Berry Distillation Column

Abstract

The purpose of a multivariable control involves maintaining various control variables at independent set points. The interactions present in the system affects more than onecontrolled variables because of the manipulated variable. Due to interaction or cross coupling in the multivariable systems, performance of a system is reduced. The dynamic and static decoupling are the two types of decoupling strategies.
In this thesis, our goal is to design a decoupler along with decentralized controller for wood berry distillation column system in order to reduce the interactions present between the manipulated variable and controlled variable. Initially, a decoupler has been designed from the plant matrix. Afterwards, depending upon the frequency response, for each of the decoupled process, a first order plus dead time model is obtained. In order to get the desired gain and phase margins, after getting the FOPDT model, a decentralized PI/PID controller for each reduced order decoupled model has been designed. All the three dynamic decoupling techniques i.e. simplified, ideal and inverted decoupling is carried out on Wood Berry distillation column system.
The characteristics like non-minimum phase and non-linear characteristics make the control of wood-berry distillation column system, a stand out amongst the most difficult benchmark control problem. Wood- Berry distillation column describes the dynamics of overhead and bottom composition of methanol and water in the column. Its main objective is to separate the methanol from water.
The decoupling effect of all the three dynamic decoupling techniques has been represented in MATLAB/Simulink. Comparison between the simplified, ideal, inverted is also been studied.