Hydrogen Induced Disbonding: from Laboratory Tests to Actual Field Conditions

Abstract Disbonding tests are often required during fabrication of hydrotreating vessels. However it is difficult to make the link between the testing conditions and the actual service conditions in the reactor wall. From numerical simulations of hydrogen profiles through disbonding test specimens and reactor walls it is possible to assess both the severity of disbonding tests and the actual risk of disbonding in service. It is shown that in-service temperature and hydrogen pressure are important parameters that control hydrogen distribution throughout the wall of a reactor, however, the influence of the wall thickness will also be underlined: the greaterer the thickness of the vessel, the greaterer the risk of disbonding. On the basis of a data bank of disbonding test results performed for fabricators world-wide, a proposal is made to adapt the severity of the test to the severity of the service conditions (pressure, temperature, wall thickness).