An active disturbance rejection control design for the distillation process with input saturation via quantitative feedback theory

Abstract

The distillation process is a major contributor to high energy consumption in the petrochemical industry. It is a complex multivariable system with input saturation, and its control problem is a critical factor that affects process energy efficiency. To address these control challenges, a new active disturbance rejection control (ADRC) design is proposed for the distillation process. The design includes a saturation compensation element with an integral structure and a nonlinear error feedback component with switched gain. The proposed control structure is effective in helping the system exit saturation in time, resulting in better dynamic performance than traditional ADRC. Additionally, a parameter tuning strategy based on quantitative feedback theory (QFT) is proposed to achieve the desired performance. The closed-loop stability conditions are analyzed using the describing functions technique to ensure the robust stability of the system. Finally, the proposed control structure and corresponding tuning strategy are applied to the distillation process. A numerical simulation and a simulation based on Aspen Plus confirm its superiority over traditional control structures. The proposed ADRC design with input saturation compensation has clear potential in the application of the distillation process.