Energy Efficiency in Furnaces

Abstract

Furnaces are among the most energy-intensive units in industrial facilities. Processes such as melting, heat treatment, firing, drying, and tempering are carried out in furnaces. Natural gas and electricity are generally used as energy sources in furnaces. Annealing furnaces operating at high temperatures in industrial processes must operate in the most efficient way in terms of fuel consumption and reduce energy consumption. In addition, it is very important to carry out studies to increase energy efficiency in furnaces in order to minimize the damage to the environment, considering the pollution caused by waste gases discharged from the furnaces.Factors affecting energy efficiency in furnaces include incomplete combustion, fuel type, air/fuel ratio, furnace wall losses, loss of clearance, flue gas temperature, scale (oxide layer)/material characteristics, and cooling water losses. It is necessary to determine the savings points and required precautions to reduce energy consumption in furnaces. For example, energy-saving rates that can be realized according to melting technology and thermal efficiency can be listed as follows, preheating of filler 5–10%, cooling 5–10%, air preheating 10–20%, mixing molten metal 5–30%, improvement of operation 0–30%, oxygen enrichment technology 0–40%, respectively.