Analysis of internal cracks in Type 304 austenitic stainless steel cladding wall of regenerator column in amine treating unit

The present study aims at investigating the incidence of internal cracks in Type 304 austenitic stainless steel cladding wall of Methyldiethanolamine (MDEA) regenerator column in amine treating unit. The toxicity of hydrogen sulfide (H2S) makes it difficult to reproduce the exact service conditions in regenerator column; therefore, it was substituted with thiosulfate solution. Slow strain rate testing (SSRT) was performed on specimens in simulated process environment of MDEA regenerator at 83 + 3 °C. In order to analyze and compare the data which collected, constant load (CL) and fracture mechanics (FM) techniques were applied by the researchers. After the failing, the fracture surfaces were observed through a scanning electron microscope (SEM) and were chemically analyzed using energy dispersive X-ray (EDXs) techniques. The results revealed that elongation ratio (ER), reduction in area ratio (RAR) and time to failure ratio (TTFR) increased rapidly in corrosive solution in the presence of 5%MDEA compared with the absence of MDEA. In addition, the specimen tested in thiosulfate solution (corrosive solution) without MDEA indicated a brittle type of failure, whereas those in the MDEA solution showed a ductile fracture.