The heat exchanger is a U-tube bundle, placed in an internally insulated casing. Fully welded tubular type exchanger, using bare tubes (stainless steel 1.4828). The hot gas is flowing outside the U-tubes in cross / counter flow with the cold air which is flowing in 2 passes inside the tubes. The stainless steel transition ducts on the air side as well as the carbon steel internally insulated transition ducts on the flue gas side were scope of supply. Flue gas is cooled from 900 to 560 degrees Celsius, and combustion air is heated from 20 to 430 degrees Celsius. This project is supplied to Mexico, to an American customer.