A DeepStar Joint Industry Program is under way to develop and demonstrate direct electrical heating of exernally insulated offshore pipelines and flowlines for the purpose of preventing or removing plugging due to hydrates or wax deposition. Two systems are being studied and tested: one requiring complete electrical insulation of the flowline from the seawater; the other requiring periodic electrical communication with the seawater through anodes or other measns. A theoretical model to predict electrical and thermal performance is being developed. Among the tests to be performed are combined bending and high voltage tests to determine insulation integrity at the field joints, and an offshore test of a 1/4-mile long section of 6" flowline to verify the predicted electrical and thermal performance of the two systems. The overall objective of the program is to provide a heated flowline up to 25 miles in length, with 25 year lifetime, which is capable of being installed in 10,000 feet of water.
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