Estudo de caso de falha em equipamento pressurizado por corrosão sob isolamento (CUI)

Abstract

Welding and corrosion present considerable challenges in pressurized equipment, such as pressure vessels, which require a high level of reliability and safety. Corrosion under insulation (CUI) is a significant issue that can compromise the integrity of equipment, regardless of the installation’s age. The repair of pressure components is fundamental and requires specific techniques, such as the welding of insert plates. The objective of this work is to design a repair and verify the quality and integrity of the welds, as well as to ensure the integrity of the equipment after it has suffered damage due to corrosion under insulation. During a scheduled shutdown for inspection and maintenance of a heat exchanger, CUI was detected due to the failure of the thermal insulation seal, resulting in considerable damage. A structural repair was carried out with insert plates welded butt-to-butt, in accordance with ASME PCC-2 and ASME BPVC Section VIII Division 1 standards. After the repair was completed, non-destructive testing and a hydrostatic test were performed, which indicated satisfactory conditions. The equipment was inspected, considered safe to operate, and approved for return to service, ensuring the quality and safety of the welding and inspection process.