Direct electrical heat (DEH) trace single piping system, fully insulated with piggy back cable return
For this system design, the flowline is a single pipe fully jacketed with insulation that provides both a thermal barrier and electrical isolation from the surrounding seawater. Current is input to one end of pipe with electrical return by piggyback cable. The primary difference between this design and the Statoil/SINTEF design is that fully insulated design has wetted insulation that must provide complete electrical isolation of the electrified pipe from seawater while the Statoil/SINTEF design has the pipe in electrical contact with the surrounding seawater.
Direct electrical heat (DEH) trace single piping system with seawater return
For this system, the flowline is a single pipe in direct contact with the seawater. Current is input to one end of the pipe, flows through the pipe and returns via seawater. The seawater return takes the place of the piggy back cable.