板翅式换热器接管封头连接部位开裂探讨

Analysis of Cracks on the Juncture of the Nozzle and the Head of the Plate Fin Heat Exchanger

本文采用有限单元法对合成氨装置空分工段引进的切换式换热器上封头和接管连接部位进行应力分析、疲劳计算。经过计算发现该部位 ,如果只校核单个设备 ,强度无问题 ,但由于 3个设备捆在一起引起附加应力 。

Cracks of different lengths were found on the outer surface of the juncture of the connecting nozzle and the head of the plate fin heat exchanger in Zhen Hai Petrochemical Complex. The causes of the cracks were investigated by conducting stress analysis for the relevant parts of the heat exchanger. Finite element method was used for the stress analysis. It is found that the axial temperature difference induces higher stress level than the internal pressure. Since the heat exchanger is 'three in one', therefore additional stresses are induced when the heat exchangers are subjected to axial temperature difference.