Corrosion Failure Analysis and Suggestion of Plate Cooler on Top of Decompression Device

The corrosion failure of a plate cooler on the top of decompression device in a petrochemical corporation was analyzed by macro-morphology observation, chemical composition analysis, metallographic observation and X-ray diffraction. Electrochemical behaviors of the used stainless steel were tested in 3.5% NaCl solution and condensate water. The results indicated that 316L stainless steel was qualified and the plate corrosion failure of the pre-cooling air cooler was due to the corrosion under the scale. Both 304 and 316L stainless steels used in air coolers can be passivatied in condensate water. From the point of view of ecomony it is suggested to use 304 stainless steel with passivation treatment.