INTEGRITY MANAGEMENT OF A HIC-DAMAGED PIPELINE AND REFINERY PRESSURE VESSEL THROUGH HYDROGEN PERMEATION MEASUREMENTS

摘要

Hydrogen permeation measurements were used in the successful operation of a sour gas pipeline subsequent to a hydrogen-induced cracking (HIC) failure in September 1992. Two joints of HIC-resistant pipe were used to repair the failed section and adjacent cut-outs. The pipeline has been operated for five years with no further instances of HIC failure. Hydrogen permeation monitoring was chosen as an integrity management tool because no techniques are currently available to inspect for HIC damage in a pipeline this size. Self-powered electrochemical devices installed or the pipeline were employed to monitor and control the effectiveness of a batch inhibition program in maintaining diffusing hydrogen atom concentrations below the laboratory-measured threshold for initiation of HIC damage. Permeation monitoring of a HIC-damaged refinery pressure vessel indicated very high hydrogen atom flux, despite attempts to inhibit corrosion with ammonium polysulfide injection. In this instance it was decided that replacement of the vessel was necessary.