Rate and grade transition control using PI controller based supervisory and regulatory layers: Diacetone alcohol...

Area of Science:

• Chemical Engineering
• Process Control
• Industrial Automation

Background:

• Process plants frequently face challenges during product rate and grade transitions due to economic demands and operational uncertainties.
• Current open-loop control of throughput manipulators (TPMs) for rate transitions leads to offsets and is sensitive to feed disturbances.

Purpose of the Study:

• To develop and evaluate a cost-effective supervisory control layer using a Proportional-Integral (PI) controller.
• To guide the plantwide regulatory layer for achieving product rate targets during grade transitions and mitigating feed disturbances.

Main Methods:

• Implementation of a PI-based supervisory control layer integrated with the existing plantwide regulatory layer.
• Simulation studies on a prototypical diacetone alcohol production process, including a reactor and distillation columns with recycle.

Main Results:

• The proposed PI-based supervisory control effectively guides the regulatory layer to achieve product rate targets.
• The control structure demonstrates improved performance during simulated rate/grade transitions and in the presence of feed disturbances.

Conclusions:

• A simple PI controller-based supervisory layer offers a viable and affordable solution for enhancing process plant operability during transitions.
• This approach obviates the need for expensive advanced process control (APC) systems, making it suitable for medium-to-small scale industries.