A novel double loop control model design for chemical unstable processes.

Area of Science:

• Chemical Engineering
• Process Control

Background:

• Unstable processes in the chemical industry pose significant control challenges.
• Existing control schemes may lack robustness or optimal performance for these systems.

Purpose of the Study:

• To propose an improved double loop control model for unstable chemical processes.
• To enhance both set-point tracking and disturbance rejection capabilities.
• To provide a simple yet effective control strategy with clear physical interpretation.

Main Methods:

• An improved double loop control model based on the Smith predictor.
• Inner loop for stabilizing the unstable process and transforming it to a stable first-order plus dead-time system.
• Outer loop for set-point response enhancement and a separate disturbance controller for disturbance response improvement.

Main Results:

• The proposed control system demonstrates simplicity and clear physical meaning.
• Stabilization is achieved easily through the characteristic equation.
• Individual controllers are straightforward to design, yielding good performance for their respective closed-loop transfer functions.
• Robust stability analysis confirms the reliability of the scheme.

Conclusions:

• The improved double loop control model effectively stabilizes and enhances the performance of unstable chemical processes.
• Case studies confirm superior system performance compared to existing design methods.
• The proposed method offers a practical and efficient solution for industrial unstable process control.