GPIC Ammonia & Methanol Reformers: Replacement of Pigtails

MCSC successfully completed the replacement of pigtails including the support systems on both the Ammonia and Methanol reformer during a major shutdown in March 2015.

The project was critical in terms of high chrome alloy steel welding during fabrication and installation, performing the pigtail tubes installation activities in locations with very limited access, replacement of pigtail tubes of both ammonia and methanol plant in a very short duration, insulation of tubes, post weld heat treatment and radiography examination requirements and commencing the production immediately after shutdown.

The pre-fabrication, NDE, PWHT and hydro test activities were carried out in MCSC workshop and all the items were dispatched to GPIC plant well ahead of schedule. The shutdown was completed on schedule in 19 days and plant was handed over on time. GPIC appreciated MCSC team for the completion of critical fabrication in workshop, installation at site, welding, PWHT, NDE, insulation and other associated activities in a professional way maintaining a high level of quality and safety

Project Highlights:


  • Prefabrication of 590 Nos. of pigtails of P91 alloy steel material and 12 Nos. of sub headers P11 alloy steel material. Special fixtures and clamps were designed and established to ease the fabrication work without distortions and maintaining workmanship.
  • Prefabrication of supports and their links.
  • Insulation in double layer and cladding of pigtails were completed prior to shut down.
  • Pigtail lifting methodology at site was established and trial was taken prior to shut down.


  • Replacement of the entire 555 pigtails at Ammonia (240 Nos.) and Methanol (315 Nos.) reformers with newly fabricated P91 material tubes.
  • Replace the 12 Nos. sub headers (P11) from the both reformers.
  • Replace/Modify the existing support system.
  • Install the double layer lagging and cladding.