利用宏观形貌观察、化学成分分析、金相观察和X射线衍射等方法, 分析了某石化公司减压塔顶预冷板式空冷器的腐蚀失效原因。采用电化学测试对常用不锈钢在3.5% NaCl溶液和减顶冷凝水中的腐蚀性能进行对比研究。结果表明,316L不锈钢材料合格,预冷板式空冷器板束腐蚀失效是由于冷却水垢下腐蚀造成的。304和316L不锈钢均在减顶冷凝水中具有钝化膜自修复能力, 从经济效益考虑, 建议选用304不锈钢, 并进行钝化处理。

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.