Simultaneous mixed‐integer dynamic scheduling of processes and their energy systems

AIChE Journal, vol. 68

Abstract

Abstract Increasingly volatile electricity prices make simultaneous scheduling optimization desirable for production processes and their energy systems. Simultaneous scheduling needs to account for both process dynamics and binary on/off‐decisions in the energy system leading to challenging mixed‐integer dynamic optimization problems. We propose an efficient scheduling formulation consisting of three parts: a linear scale‐bridging model for the closed‐loop process output dynamics, a data‐driven model for the process energy demand, and a mixed‐integer linear model for the energy system. Process dynamics is discretized by collocation yielding a mixed‐integer linear programming (MILP) formulation. We apply the scheduling method to three case studies: a multiproduct reactor, a single‐product reactor, and a single‐product distillation column, demonstrating the applicability to multiple input multiple output processes. For the first two case studies, we can compare our approach to nonlinear optimization and capture 82% and 95% of the improvement. The MILP formulation achieves optimization runtimes sufficiently fast for real‐time scheduling.

Authors 3

1. Florian Joseph Baader Aachen Faculty of Mechanical Engineering

   RWTH Aachen University · Forschungszentrum Jülich

   Affiliation as printed

   Faculty of Mechanical Engineering RWTH Aachen University Aachen Germany

   Institute of Energy and Climate Research, Energy Systems Engineering (IEK‐10) Forschungszentrum Jülich GmbH Jülich Germany

   Institute of Energy and Climate Research, Energy Systems Engineering (IEK‐10) Forschungszentrum Jülich GmbH Jülich Germany

2. André Bardow Aachen Institute of Technical Thermodynamics

   RWTH Aachen University · ETH Zurich · Forschungszentrum Jülich

   Affiliation as printed

   Energy & Process Systems Engineering ETH Zürich Zürich Switzerland

   Institute of Energy and Climate Research, Energy Systems Engineering (IEK‐10) Forschungszentrum Jülich GmbH Jülich Germany

   Institute of Technical Thermodynamics RWTH Aachen University Aachen Germany

   Institute of Energy and Climate Research, Energy Systems Engineering (IEK‐10) Forschungszentrum Jülich GmbH Jülich Germany

3. Manuel Dahmen corresponding

   Forschungszentrum Jülich

   Affiliation as printed

   Institute of Energy and Climate Research, Energy Systems Engineering (IEK‐10) Forschungszentrum Jülich GmbH Jülich Germany