Structural assessment for pressure vessel defects

Due to the shear size of the pressure vessel column, around 75m height, it was required that repairs were conducted with the column in situ, the consequence of failure would disable this expensive piece of equipment and potential cause catastrophic damage to the nearby site.

To reach these repair locations, significant towers or scaffolding were required, and these would require the support of the vessel to resist wind loads. To expedite repair operations to within the turnaround time scale multiple repairs would be conducted concurrently.

Several layers of analysis including linear and non-linear Finite Element Analysis (FEA) was then conducted to investigate possible repair options and the effects on the vessel during these repairs. This included evaluating the effect of wind loading on the sheeted scaffolding and the corresponding force transfer to the column while the vessel had holes cut out of its shell.

Regular correspondence was had with other sub-contractors to understand which repair strategies were feasible, providing the practical knowledge to help DOCAN optimize the proposed repair scheme. Welding simulation was used in Simufact Welding to determine the extent of the Heat Affected Zone (HAZ).