Metal Heating Furnace with Flue Gas Condensation. A Thermoeconomic Analysis

Abstract

The heat treating furnaces are one of the largest energy consumers in the manufacturing sector and therefore many techniques to improve their energy efficiency have been developed. One of them focuses on the recovery of the heat contained in exhaust gases and its use to preheat combustion air/charge or to generate steam. The maximum amount of recovered heat is obtained when the flue gases are cooled down below dew point temperature in order to recover the latent heat of water vapor in flue gases. The use of a condensing economizer in a 70 t/h heat treating furnace allows the decrease of the cost of heated metal bars by 0.32%, which means a cost saving of 158 lei/h.