AITESA was responsible for the design, supply and assembly supervision of a convection recuperator for a walking beam furnace at a steel plant in Gijón (Spain). Heat recuperators allow the preheating of combustion air by means of the very high temperature gases which are produced in steelmaking furnaces, glass melting furnaces, waste solvent incinerators and H2 petrochemical furnaces. These heat recuperators can be convection or radiation type.

In this case, heat transfer between the primary and secondary fluids is by convection. When the temperature of the fumes is very high, dilution air is used to reduce it and avoid damaging the materials. The convection recuperator receives the hot gases from the furnace at 850ºC, and by means of the transferred heat raises the combustion air temperature to 550ºC, for a total transferred power of 10MWt.

With combustion air preheating, a significant improvement in furnace efficiency is achieved.