Failure analysis and life prediction of a large, complex plate fin heat exchanger

Abstract

Failure analysis and life prediction of a large, complex fin plate heat exchanger required metallurgical analysis, at the beginning of 1993, inter-stream leaks were found in two aluminium plate fin heat exchangers in parallel operation at a petrochemical plant. One of the exchangers could be repaired and was returned to service, the other was scrapped. The Council for Scientific and Industrial Research (CSIR) was approached to carry out a metallurgical investigation on a section of the scrapped heat exchanger, to determine the temperature and resulting stress distributions, and to perform a life assessment. The appraisal revealed that failure was due to design or manufacturing errors, excessive thermal loads, both steady and transient and freezing of condensed moisture in gas streams. Temporary and steady-state conditions were analysed. Three predetermined element models were tried before success was achieved.