Bridging Planning, Scheduling, and Real-Time Operations: Expanding the Horizon of APC with Multiperiod Optimization

The paper presents a transformative technology redefining the process industry's Advanced Process Control (APC) boundaries through multiperiod optimization.

This innovative approach consolidates planning, scheduling, and real-time operations into a cohesive optimization framework, facilitating swift adaptations to fluctuating market conditions and increasing operational resilience. Enhancing adaptability, the methodology ensures synchronized orchestration across various process units, promoting just-in-time production and strategic maneuverability in response to process changes, from blending lineups to feed composition switches.

Users can harness models from pre-existing multivariable predictive control (MPC) applications to illustrate linear interrelationships between variables. This approach capitalizes on the substantial investments previously made in advanced process control. Additionally, users have the flexibility to create custom models, employing both linear and non-linear equations to define relationships between variables. For instance, non-linear blending functions can be applied to tank compositions, while reactor models can utilize non-linear yield functions. Furthermore, the model possesses the capability to interface with the planning and scheduling system. This facilitates the integration of financial values, updates on present and anticipated tank line-ups, as well as modifications in operational modes.

With its local and short-term optimization focus, conventional APC often falls short in addressing broader operational challenges. In contrast, this technology boldly broadens the optimization horizon and significantly expands its scope. This allows us to obtain more benefits than conventional APC applications.

The increased scope and horizon allow for the inclusion of planning and scheduling objectives and constraints that can be solved simultaneously.

The paper includes practical case studies in refinery kerosene blending and ethylene cracker units that clearly illustrate this optimization methodology's efficacy and strategic superiority.