Case Study of Optimal Byproduct Gas Distribution in Integrated Steel Mill Using Multi-Period Optimization

Abstract

Energy constitutes about 20 % of the total production cost in an integrated steel mill, and therefore energy efficiency is crucial for profitability within the environmental policy context. An integrated steel mill generates high calorific value byproduct gases at varying rates. The differences between gas generation and consumption rates are compensated with gas holders. However, under certain circumstances the imbalances can lead to the flaring of excessive gas or require the purchase of supplementary fuel. This presentation describes a steel mill energy management system with sophisticated monitoring, planning, and optimization tools. It models the complex energy interconnections between various processes of the mill and determines the optimal trade-off between gas holder level control, flare minimization, and optimization of electricity purchase versus internal power generation. The system reduces energy cost, improves energy efficiency, manages carbon footprint, and provides environmental reporting features.