Production and scheduling optimization of a steel plant

Iiro Harjunkoski*, Sleman Saliba, Matteo Biondi, Chaojun Xu, Heiner Termeer

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Abstract

This paper discusses production scheduling and optimization of a melt shop and hot-rolling mill of a steel plant. In both cases, the production schedule must comply with strict, often conflicting production rules derived from metallurgic and physical constraints. Manual planning is very challenging, since it requires years of experience and ability to efficiently react to unforeseen situations. Today, planning must be more agile than ever due to very volatile markets and increasing competition. Thus, improving the optimization of the production has become interesting to many companies. Typically, the steel-making process can be roughly divided into three parts: the melt shop, where melt steel is produced and cast into intermediate products (slabs), the hot rolling, in which slabs are formed by means of a mechanical and thermal process into coils or plates. At the end, coils are processed in a cold rolling mill and finishing lines to reach the different customers' specifications e.g. final dimensions, surface quality and mechanical properties. These production steps are highly interconnected. Therefore, the ideal situation would be to comprise all of them into one optimization model. However, this is very challenging, due to the different problem characteristics, as well as computational and modeling limitations. The presented approaches combine intelligently mathematical optimization methods with heuristics in finding optimal or close-to-optimal solutions for the melt-shop and hot rolling production. The solutions have been implemented in a flexible framework applying ISA-95 standards and web service interfaces. This allows an adjustable and configurable integration of the solutions. It opens the opportunity for finding further synergies to enable significant energy saving potential. This paper presents the main solution concepts, which have been implemented at a pilot customer plant. Main benefits are higher throughput, better customer due date reliability and predictability, fast, efficient and stable production schedules and improved visibility throughout the plant.

Original languageEnglish
Title of host publicationProceedings - European Metallurgical Conference, EMC 2011
Pages593-604
Number of pages12
Volume2
Publication statusPublished - 2011
MoE publication typeA4 Article in a conference publication
EventEuropean Metallurgical Conference - Dusseldorf, Germany
Duration: 26 Jun 201129 Jun 2011

Conference

ConferenceEuropean Metallurgical Conference
Abbreviated titleEMC
Country/TerritoryGermany
CityDusseldorf
Period26/06/201129/06/2011

Keywords

  • Enterprise-wide optimization
  • Hot rolling
  • ISA-95
  • Melt shop
  • Mixed integer linear programming
  • Scheduling
  • Steel plant

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