Failure analysis of fire resistant fluid (FRF) piping used in hydraulic control system at oil-fired thermal power generation plant

摘要

This is a case study regarding frequent forced outages in an oil-fired power generating station due to failure of fire resistant fluid (FRF) piping of material ASTM A-304. This analysis was done to find out the most probable cause of failure and to rectify the problem. Methods for finding and analyzing the cracks include nondestructive testing techniques such as visual testing (VT) and dye penetrant testing (PT) along with that periodic monitoring after rectification of problem. The study revealed that pitting and pit to crack transitions were formed in stainless steel piping containing high pressure (system pressure 115 bars) fire resistant fluid. However, after replacement of piping the pitting and cracking reoccurred. It was observed that due to possible exposure to chlorinated moisture in surrounding environment pitting was formed which then transformed into cracks. The research work discussed in this paper illustrates the procedure used in detection of the problem and measures taken to solve the problem.