AN INTEGRATED PRODUCTION PLANNING AND CONTROL SYSTEM FOR STEELMAKING FACILITIES WITH AN ENERGY CONSERVATION CRITERION

This research has attempted to include energy conservation criteria into the production planning and control function in an integrated steel plant. The energy sources in an integrated steel plant can be simply classified into two categories: outside supply source and inside co-generated energy. For short term scheduling, the plant usually assumes that there is a constant supply of externally supplied energy. Therefore, this research has concentrated its effort on optimizing the use of the co-generated energy. The production control strategy developed in this research is to make a weekly, energy efficient, production plan for each process by means of solving a mixed integer linear programming formulation which considers the entire plant. The weekly production plan will generate the weekly production level for each kind of product for each process. Then, each process can create a detailed schedule based on the production level set by the weekly production plant. However, the development of specific scheduling algorithms for each process is not included in this research. A simulation model which duplicates the configuration of an example integrated steel plant was developed to evaluate the developed strategy. Significant improvements were shown for numerous characteristics, such as unit energy measure and total potential marginal value of shipped final product as a result of applying this strategy. It is also concluded, based on a sensitivity analysis, that the improvement in unit energy measure by using the weekly production plan is an inverse proportion of the demand level