Energy Efficiency Improvement by Measurement and Control: A Case Study of Reheating Furnaces in the Steel Industry

Abstract

The aim of this paper is to analyze the possibilities for energy efficiency improvements through utilization of measurement and automatic control; this includes both direct fuel savings and indirect savings due to product quality improvements. Focus is on energy use in steel reheating furnaces for rolling mills. The demands on the reheating process and the operational conditions that are essential for its control are described. An analysis is made of possible reductions in energy use as a result of improved control. A survey is included of furnace control systems in steel plants; such equipment has been designed and implemented in order to optimize the reheating process. Reports of achieved savings are presented, and demands on measurement and control systems for successful implementation are discussed. Economic analyses, in terms of life cycle costs and estimated savings, are made for three levels of measurement and control systems. Reductions in energy use of up to 20 percent can be expected for the type of process studied, as a result of investments in information technology; it is also concluded that such investments are cost-effective.