MINLP Formulation for Simultaneous Planning, Scheduling, and Control of Short-Period Single-Unit Processing Systems

Abstract

A simultaneous strategy for solving the integrated planning, scheduling and control problem considering short-term periods is proposed in this paper. The problem is formulated as a mixed integer dynamic optimization problem. The main practical motivation to use a simultaneous, rather than a sequential solution strategy is to seek improved optimal solutions by considering the interactions among planning, scheduling and control. Integration of the three levels of the problem represents a challenge given the very different horizon times involved in the operations, resulting in growth of the problem in terms of the number of equations to be solved, and hence on computational requirements to carry it out. A full space approach was used rather than trying a decomposition strategy. Moreover, a nonlinear model predictive control strategy was also used to account for on-line product transition trajectories. The integrated planning, scheduling and control is formulated as a mixed integer dynamic optimization model, which is tested using the dynamic models of three continuous stirred tank reactors featuring different nonlinear behavior.

Economic Benefit from Progressive Integration of Scheduling and Control for Continuous Chemical Processes

“…Literature on ISC reactive to market fluctuations is relatively limited in scope. Gutierrez-Limon et al demonstrated integrated planning, scheduling, and control responsive to fluctuations in market demand on a CSTR benchmark application [36,37]. Pattison et al investigated ISC with an air separation unit (ASU) in fast-changing electricity markets, responding optimally to price fluctuations [42].…”

Combined Noncyclic Scheduling and Advanced Control for Continuous Chemical Processes

“…Benefit is demonstrated from using multi-objective approaches with Pareto fronts rather than combining economic and dynamic performance objectives into a single objective function. Gutierrez-Limon and Flores-Tlacuahuac also investigate simultaneous planning, scheduling, and control for continuous chemical processes using a large MINLP problem and NMPC [41]. Prata et al study the use of outer approximation methods for the solution of integrated scheduling and control problems [42].…”

Model-based multi-parametric programming strategies towards the integration of design, control and operational optimization

“…[70,119] Simultaneous/Decomposition (MI)DO schedule and P-PI-PID control [58,93,225,269] Simultaneous/Decomposition algorithms using control/dynamics aware scheduling models [42,122,370] Simultaneous/Decomposition algorithms via (MI)DO reformulation to (MI)NLP [161,183,184,277,335,336] Control theory in scheduling problems [146,147,277,362] Advanced control and (MI)NLP scheduling schemes [75,158,166,204,270] Scheduling under uncertainty [19,29,102,126,142,153] Review articles on scheduling and control and methodologies…”