Direct electric pipeline heating
AssigneeShell Oil Company
InventorsRonald Marshall Bass, Carl Gottlieb Langner
Life of this patent
Estimating the term…
Abstract
A system for direct electric heating of a subsea pipeline is disclosed in the form of a pipe-in-pipe flowline having an electrically conductive outer carrier pipe and an electrically conductive inner pipe or flowline arranged longitudinally, substantially concentrically within the outer pipe. An annulus is defined between the inner and outer pipes and a pipe insulating joint assembly structurally joins, but electrically insulates, the inner and outer pipes at a first end of the subsea pipeline. A power input provided on the surface facilities is electrically connected across the inner and outer pipes at the first end of the pipeline, and an electrical pathway completes the circuit by connecting the inner and outer pipes at the second end of the pipeline.
Claims19
A system for direct electric heating of a pipeline, comprising:
- a pipe-in-pipe flowline, comprising:
- an electrically conductive protective outer pipe;
- an electrically conductive inner pipe arranged longitudinally, substantially concentrically within the outer pipe;
- an annulus defined between the inner and outer pipes;
- a pipe insulating joint assembly which structurally joins but electrically insulates the inner and outer pipes at a first end of the pipeline;
- and
- an electrical pathway electrically connecting the inner and outer pipes at a second end of the pipeline;
- and
- a power input electrically connected across the inner and outer pipes at the first end of the pipeline.
A system for direct electric heating of a pipeline, comprising:
- a pipe-in-pipe flowline, comprising:
- an electrically conductive protective outer pipe;
- an electrically conductive inner pipe arranged longitudinally, substantially concentrically within the outer pipe;
- a thick, arc-resistant plastic coating on the outside of the inner pipe;
- an annulus defined between the inner and outer pipes;
- a plurality of thermally and electrically insulative centralizers spaced at intervals along the annulus to prevent electrical contact as well as to reduce conductive heat transfer between the inner and outer pipes;
- a plurality of low density, plastic foam insulators placed in the annulus around the inner pipe between the centralizers;
- a pipe insulating joint assembly which structurally joins but electrically insulates the inner and outer pipes at a first end of the pipeline;
- and
- an electrical pathway electrically connecting the inner and outer pipes at a second end of the pipeline;
- a power input electrically connected across the inner and outer pipes at the first end of the pipeline, comprising:
- an AC generator;
- an electrical penetrator in electrical communication with the inner pipe through the pipe insulating joint assembly;
- a first terminal electrically connected to the outer pipe at the first end of the pipeline;
- a second terminal electrically connected to the inner pipe through the electrical penetrator;
- and
- an electrical transformer having a primary coil connected to the AC generator and a secondary coil the first and second terminals at the first end of the pipeline.
Dependencies are inferred from the claim text.