Foam Jacket Anticorrosion and Thermal Insulation Structure

The status and corrosion reason of foam jacket anticorrosion and thermal insulation structure used in oil pipelines are introduced.For bare steel pipes wrapped by polyurethane(PU) foam thermal insulation without anticorrosive coating,failure in coating joint,cleft and disfigurement of polyethylene(PE) layer and water penetration into the thermal insulation layer are main reasons that cause the pipe corrosion.The characteristics of common materials used for anticorrosive coating,thermal insulation and outer shield are compared.A new 3-layer anticorrosion and thermal insulation structure composed by fusion bonded epoxy(FBE) (coal tar enamel),PU foam thermal insulation and coal tar enamel is discussed and some issues related to applying this new structure are also discussed.