某石化公司乙烯厂乙烯装置的核心设备第二急冷换热器于2018年5月突然发生泄漏，导致设备停车。检修发现本次泄漏主要发生在换热器壳体靠近上管板的第一节筒节,壳体失效位置存在贯穿性裂纹，裂纹已沿厚度方向完全开裂。为此，查阅了该设备的原始制造资料，进行了换热器筒体开裂现象的应力分析、宏观检查和取样分析。最终确定碱应力腐蚀是引起换热器筒体失效开裂的根本原因，并提出了相应的防止措施。

The second quench heat exchanger is the core equipment of the ethylene plant of a petrochemical company.There was a sudden leak in the heat exchanger in May 2018, causing the equipment to stop.Through the inspection it was found that the leakage mainly occurred in the first barrel section of the heat exchanger shell near the upper tube plate.There was a penetrating crack in the failure position of the cylinder, and the crack was completely cracked along the direction of thickness.For this, the original manufacturing data of the equipment were reviewed, and the stress analysis, macroscopic examination and sampling analysis of the cracking phenomenon of the cylinder of the heat exchanger were carried out.Results showed that alkali stress corrosion was the fundamental cause of heat exchanger cylinder failure and cracking, meanwhile the corresponding preventive measures were put forward.