State-of-the-art composite technologies for internal repair

A number of innovations and new composite technologies are now available for pipeline repair in deep water projects in the oil and gas industry (Stringfellow et al., 2006). Generally, composite pipes for gas distribution systems arc classified based on the maximum allowable operating pressure (Beech, 2009), as listed in Table 13.2. 

Less than 40 Local transmission lines (medium pressure) 

Rehabilitation of Pipelines Using Fiber-reinforced Polymer (FRP) Conqtosites 

Rehabilitation of pipes by CIPP, with thermoset polyester resins and polyester felt, usually requires satisfying predetermined specificalions for both materials and installation. With CIPP, a tubular hner is saturated with a resin, which is then inserted into the damaged pipe and cured via heat and/or ambient or ultra violet light. The pipe defect is initially identified and located, usually by means of a closed circuit television survey or PIG. The resin saturated liner is then inserted into the pipe and inflated against the wall of the pipe by air or water pressure. The resin cures and hardens into a smooth structure and a new composite pipe is created within the old pipe. The materials used to manufacture the components are chosen to suit the function of the repaired pipeline. The combination of the hner, resin, the method of installation and the chosen curing method will determine the overall quality of the end product. 

The flexible, tubular hner of a CIPP is typically made of polyester fabric that is a needled, woven or knitted reinforced fibre sheet using carbon, glass or aramid fibres or a combination of both. Depending on its application, the hner is coated with an impervious film such as polyethylene for the transport of drinking water or polyester for gas pipes. Other coatings include urethane and polyvinyl chloride (PVC). The final smooth surface reduces the surface friction and provides an additional corrosion barrier for the pipe. Liner tube sizes range from 100 to 2500 mm in diameter with 

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