Direct Electrical Heating of a Flexible Pipe

This paper describes a new direct electrical heating method in flexible-pipe systems. The method effectively expands the operational envelope of flexible unbonded pipes by offering prevention and removal of hydrate plugs and mitigation of wax precipitation by distributed heating along the entire pipe length. The direct-electrical-heating solution is effectively operated as a coaxial cable, where electrical current is passed through the carcass and returned through the tensile-armor (TA) layers.

The Concept of Direct-Heated Flexible Pipes

The general structure of the flexible unbonded pipe is shown above. The inside of the pipe consists of a stainless, wound carcass surrounded by a polymeric pressure sheath defining the fluid barrier.