Bundles and towed installation

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Bundles and towed installation

INSULATION SYSTEMS USED FOR BUNDLES

ƒ High temperatures and low OHTCs required ƒ U better (less) than 1 W/m²/K (0.176 BTU/ft²/hr/F°) ƒ Possible systems are: ƒ Low density polyurethane foam ƒ Microporous silica ƒ Mineral or glass wool ƒ Syntactic polyurethane (SPU) ƒ Polypropylene (PP) ƒ Silica aerogels ƒ P-I-P with air gap ƒ Avoids half-shells Aerogel (solid smoke) FBE coated carrier pipe There are a number of possible solutions available using bundles to achieve very high insulation values. The following slides give typical properties: k values are based on a typical 219.1 mm (8 in) pipe. Even for a single pipe-in-pipe, the bundle option may be selected. However, if the insulation is not injected into the annulus of the P-I-P, and the outer sleeve can move, it is possible to avoid the use of half-shell welding at each of the 12 m (40 ft) joints. This is the case for all but the injected foamed products listed above. Foam can be applied in preformed cast sections or helically wrapped on. Where: OHTC = overall heat transfer coefficient LDPUF insulated flowline in P-I-P sleeve pipe

COMPARISONOFMATERIALS