Abstract: The waste heat recovery system of heating furnace in S Zorb unit is reconstructed by making use of the advantages of ultra-low temperature FAE exchanger. The problems of air leakage, corrosion, insufficient heat transfer area and potential hidden troubles of induced draft fan in the heat pipe air preheater of the original waste heat recovery system were solved after the reconstruction. Meanwhile, thermal efficiency of the heating furnace was increased from 91.5% to 94.3%, and considerable economic and social benefits were obtained. The combined ultra-low temperature FAE exchanger can be used not only in the old furnace reconstruction, but also in new devices. It has made certain contribution to the deep energy saving and emission reduction of heating furnace in petrochemical enterprises.

Key words: S Zorb, energy-saving reconstruction, FAE exchanger, plate preheater, dew point corrosion