SCC in Oil Refineries. Monoethanolamine
(MEA) is an absorbent used to remove acid gases
containing H2S and CO2 in oil refining operations.
Recent failures in several refineries have
shown that cracks can be parallel or normal to
welds, depending on the orientation of principal
tensile stresses. Cracking has been reported to
be both transgranular and intergranular.
Before 1978, postweld stress relief of carbon
steel weldments in MEA systems was performed
only when the metal temperature of the equipment
was expected to exceed 65 C (150 F)
and the acid gas contained more than 80% CO2
or when temperatures were expected to exceed
95 C (200 F) in any acid gas concentration