Implementation of an integrated production and electricity optimization system in melt shop

Abstract The production of stainless steel begins by melting of scrap in melt shop that is known as one of the most electricity intensive processes. Volatile and uncertain renewable energy sources cause high fluctuations in electricity prices and thus usually higher costs for the final user such as a melt shop. This paper presents an integrated production and electricity optimization system that can help the melt shop to adjust its production schedule to volatile electricity prices and thus lower its costs. An existing production scheduling optimization system based on a continuous-time mixed-integer linear programming model has been further developed to account for electricity costs as well. It deploys an intelligent heuristics which decomposes the overall optimization problem into several sub-problems of smaller size in order to achieve faster and more robust solution. The electricity-aware optimization system has been successfully tested and implemented in a melt shop where it managed to reduce electricity costs by around 3%. At the same time, the system has improved coordination between different production stages, and thus made the entire melt shop more flexible, agile and responsive to unexpected events. The system has also been recognized as a very useful tool for running various simulations, what-if analysis and business scenarios on the melt shop in order to identify bottlenecks and further increase its production rate.

[1]  Christos T. Maravelias,et al.  General framework and modeling approach classification for chemical production scheduling , 2012 .

[2]  François Soumis,et al.  Hierarchical Approach to Steel Production Scheduling Under a Global Energy Constraint , 1988 .

[3]  Pedro M. Castro,et al.  Optimal maintenance scheduling of a gas engine power plant using generalized disjunctive programming , 2014 .

[4]  Manfred Morari,et al.  Electrical load tracking scheduling of a steel plant , 2010, Comput. Chem. Eng..

[5]  Iiro Harjunkoski,et al.  Flexible and Configurable Steel Plant Scheduling System , 2009 .

[6]  Ignacio E. Grossmann,et al.  Optimization of steel production scheduling with complex time-sensitive electricity cost , 2015, Comput. Chem. Eng..

[7]  Ignacio E. Grossmann,et al.  Optimal scheduling of industrial combined heat and power plants under time-sensitive electricity prices , 2013 .

[8]  Manfred Morari,et al.  Robust integer optimization and scheduling problems for large electricity consumers , 2012, 2012 American Control Conference (ACC).

[9]  Lin Li,et al.  Plant-level electricity demand response for combined manufacturing system and heating, venting, and air-conditioning (HVAC) system , 2016 .

[10]  Lixin Tang,et al.  A review of planning and scheduling systems and methods for integrated steel production , 2001, Eur. J. Oper. Res..

[11]  Christian Artigues,et al.  An hybrid CP/MILP method for scheduling with energy costs , 2010 .

[12]  S. Ashok,et al.  Peak-load management in steel plants , 2006 .

[13]  Stefano Di Gennaro,et al.  Modelling of electrical energy consumption in an electric arc furnace using artificial neural networks , 2016 .

[14]  Iiro Harjunkoski,et al.  Flexible and configurable MILP-models for meltshop scheduling optimization , 2008 .

[15]  Ignacio E. Grossmann,et al.  Enterprise‐wide optimization: A new frontier in process systems engineering , 2005 .

[16]  Zeyi Sun,et al.  Inventory control for peak electricity demand reduction of manufacturing systems considering the tradeoff between production loss and energy savings , 2014 .

[17]  Ignacio E. Grossmann,et al.  Optimal production planning under time-sensitive electricity prices for continuous power-intensive processes , 2012, Comput. Chem. Eng..

[18]  Christian Artigues,et al.  On electrical load tracking scheduling for a steel plant , 2011, Comput. Chem. Eng..

[19]  Víctor Manuel Fernandes Mendes,et al.  Self-scheduling and bidding strategies of thermal units with stochastic emission constraints , 2015 .

[20]  I. Grossmann,et al.  A decomposition approach for the scheduling of a steel plant production , 2001 .

[21]  Ignacio E. Grossmann,et al.  Incorporating scheduling in the optimal design of multiproduct batch plants , 1989 .

[22]  Zeyi Sun,et al.  Customer-side electricity load management for sustainable manufacturing systems utilizing combined heat and power generation system , 2015 .

[23]  Pedro M. Castro,et al.  Scope for industrial applications of production scheduling models and solution methods , 2014, Comput. Chem. Eng..

[24]  Steven H. Rich,et al.  Scheduling and sequencing of batch operations in a multipurpose plant , 1986 .

[25]  Iiro Harjunkoski,et al.  Resource–Task Network Formulations for Industrial Demand Side Management of a Steel Plant , 2013 .

[26]  Ulku Yetis,et al.  The environmental impacts of iron and steel industry: a life cycle assessment study , 2016 .