Feed Water Knock Out Drum - Project


The Free Water Knock Out (FWKO) Drum located in Ninian Central Platform is a three phase separator. The vessel had been out of service as a result of several anomalies in vessel body and nozzles. It was required to refurbish the vessel and bring it back into service for the remaining life of the platform (circa 10 years). Various inspection including visual, radiographic and ultrasonic test have been carried out to identify and monitor the anomalies on the shell, domes, nozzles, welded internals and flange faces. As part of this project 44 inspection reports were reviewed and the anomalies were addressed. An ASME Sec.VIII-Div.1 code calculation and API 579 Level 1 FFS assessment were performed to ascertain whether the defected components were still fit for service or remedial work was required. Several areas were found unacceptable which would require repair for continued safe operation of the vessel. The following I the summary of the findings and recommendation:

A summary of the required works is:

  • Weld overlay repair on 12 internal surface anomalies
  • Replacement of 11 nozzles
  • Replacement of 2 flanges
  • Polymer repair on 26 flange faces
  • NDT on weld repairs as instructed
  • Pressure test
  • Re-instating of internal coating and external paint touch-up
  • Re-instating of sand removal system if required
  • Fitment of new sacrificial anodes
  • Re-establishment of earthing boss cables