Live High Temperature Repair of Vapour Tank

Overview

A vapour tank vessel had suffered chloride induced corrosion that required an urgent repair without the use of hot work. The design of the repair required a defect model that would reflect complete section loss of the welded connections for a series of nozzles, and the vessel head circumferential weld.

Scope

The tank had the following specifications:

Structure	Vapour tank vessel
Surface Preparation	Sa 2.5
Design Pressure	340 kPa
Design Temperature	2200C
Application Temperature	50-1100C
Design Life	5 years
Wrap Length	6.5 m
Vessel Diameter	2.0 m
Geometry	Vessel circumference, nozzles on dome end, lifting lugs on vessel side
Corrosion Type	External
Defect Details	3mm loss on circumferential weld and 25mm through-wall defect on nozzle welds

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Solution

• Technowrap 2K™ HT system with temperature capability up to 220°C
• A highly skilled team of wrapping specialists with experience in high temperature applications
• Vacuum bag consolidation for the component onto the dome ends
• Coverage of a large part of the vessel dome end - circumference weld line, nozzles and lifting lugs, supplementing steel with fibre reinforced epoxy

Benefits

• Repair completed without hot works
• No impact on production, tank remained live (at high temperature) during the repair
• Wide chemical resistance, capable of constant exposure to chloride in various forms
• Documented QA/QC procedures provide an excellent record of the repair materials and application process for future reference