MILP performance improvement strategies for short-term batch production scheduling: a chemical industry use case

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

Abstract

This paper presents the development and mathematical implementation of a production scheduling model utilizing mixed-integer linear programming (MILP). A simplified model of a real-world multi-product batch plant constitutes the basis. The paper shows practical extensions to the model, resulting in a digital twin of the plant. Apart from sequential arrangement, the final model contains maintenance periods, campaign planning and storage constraints to a limited extend. To tackle weak computational performance and missing model features, a condensed mathematical formulation is introduced at first. After stating that these measures do not suffice for applicability in a restrained time period, a novel solution strategy is proposed. The overall non-iterative algorithm comprises a multi-step decomposition approach, which starts with a reduced scope and incrementally complements the schedule in multiple subproblem stages. Each of those optimizations holds less decision variables and makes use of warmstart information obtained from the predecessor model. That way, a first feasible solution accelerates the subsequent improvement process. Furthermore, the optimization focus can be shifted beneficially leveraging the Gurobi solver parameters. Findings suggest that correlation may exist between certain characteristics of the scheduling scope and ideal parameter settings, which yield potential for further investigation. Another promising area for future research addresses the concurrent multi-processing of independent MILPs on a single machine. First observations indicate that significant performance gains can be achieved in some cases, though sound dependencies were not discovered yet.

Details

Original languageEnglish
Article number87
Journal SN applied sciences
Volume4
Issue number4
Publication statusPublished - 2 Mar 2022
Peer-reviewedYes

External IDs

ORCID /0000-0002-1484-7187/work/173054718
unpaywall 10.1007/s42452-022-04969-2
Mendeley 1513bec2-36cd-3d49-be86-61168ba77a2d

Keywords

Keywords

  • Batch scheduling, Chemical industry, Gurobi, Makespan minimization, MILP performance, Mixed integer linear programming, Multi-product plant, Multi-stage, Parallel units