Metal scrap preheating using flue gas waste heat

The implementation of solid scrap preheating furnaces in the metal industry, powered by waste heat, has been a subject of interest due to the economic and energy saving benefits. Metal holding furnaces, keeping metal in a liquid state before casting, are powered by natural gas burners. Flue gases exit the furnaces at temperatures higher than the melting temperature of the metal, and it carries a significant amount of exergy that is considered as losses. By directing hot flue gases from the holding furnace to a metal scrap preheating furnace, one can heat up solid-scrap profiles, which are to be remelted, before putting them in the melting furnace. Adding a preheating step will reduce the melting time required while saving energy. The aim of this study is to look at the effectiveness of heating sow profiles with hot flue gases and find the optimal design considerations for a preheating furnace. Turbulent fluid flow and heat transfer physics are coupled in a CFD model to predict the sow average and maximum temperature with time for specific flue gas flow rate. (C) 2007 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license