Cailiao Baohu (Sep 2022)
Corrosion Behavior of Steels Commonly Used in Heat Exchanger Tube in High - Temperature Medium of Condensate Water Containing Elemental Sulfur
Abstract
As the deposition of elemental sulfur may cause severe corrosion perforation risk in heat exchanger tube, it is necessary to clarify the suitability of commonly used heat exchanger tube materials in elemental sulfur - containing environments. In this paper, the corrosion behaviors under high - temperature environment containing elemental sulfur of three commonly used materials for heat exchanger tube, including 20# steel, 316L austenitic stainless steel and 2205 duplex stainless steel, were investigated by immersion test with the help of scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X - ray diffractometer (XRD). Results showed that: in the 220 ℃ medium of condensate water containing 2% (mass fraction ) elemental sulfur, the average corrosion rate of 20# steel could reach 10.520 mm/a, the pitting corrosion rate of 316L stainless steel could reach 0.470 mm/a, and the corrosion rate of 2205 duplex stainless steel was only 0.036 mm/a. In addition, the main corrosion product of all the three materials was FeS2. The corrosion film on the surface of 20# steel was loose and porous, thus could only provide a poor protection. The corrosion film of 316L stainless steel and 2205 duplex stainless steel had better uniformity and density than that of 20# steel. Furthermore, 2205 duplex stainless steel could meet the service requirements of heat exchanger tubes under the as - mentioned working condition.
Keywords
