Evaluation of the energy efficiency of an aluminum melting furnace for a Nigerian cast-coiled plant

Abstract

The energy efficiency of the aluminum melting furnace was evaluated for a Nigerian cast-coiled plant. The energy input was evaluated using the daily production data of the company while the energy output was determined through the second law of thermodynamics. The energy intensity for processing 876,357 kg of aluminum scrap was estimated as 6.07 MJ/kg. The energy efficiency of the melting furnace was evaluated as 18% in which the overall excess energy of the system was 82% (4.36 TJ) of the supplied energy. The heat released to the surrounding from the stack gas was significant, accounting for almost half of the energy output (46.2%) (2.4 TJ). The lost energy from the furnace is around 36% (1.9 TJ) of the total input energy. The installation of the recuperator and waste heat recovery systems was proposed to increase the energy efficiency of the reverberatory furnace. The results of this work has shown the area of energy wastage and the information would be beneficial for the designs of new furnace or for the modification of the existing one.

Keywords

• Aluminum
• Aluminum scrap
• Cast coil
• Combustion
• Energy efficiency
• Reverberatory furnaces