US 12,313,202 B2
Method and system for direct electric heating of a double-walled pipe for transporting fluids
Raymond Hallot, Voisins le Bretonneux (FR)
Assigned to SAIPEM S.A., Montigny le Bretonneux (FR)
Appl. No. 17/259,363
Filed by SAIPEM S.A., Montigny le Bretonneux (FR)
PCT Filed Jun. 24, 2019, PCT No. PCT/FR2019/051536
§ 371(c)(1), (2) Date Jan. 11, 2021,
PCT Pub. No. WO2020/016498, PCT Pub. Date Jan. 23, 2020.
Claims priority of application No. 1856544 (FR), filed on Jul. 16, 2018.
Prior Publication US 2021/0301964 A1, Sep. 30, 2021
Int. Cl. F16L 53/37 (2018.01); F16L 59/14 (2006.01)
CPC F16L 53/37 (2018.01) [F16L 59/143 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A Direct Electrical Heating system of a Pipe-In-Pipe pipeline for transporting fluids, the pipeline comprising a steel inner shell intended to transport fluids and a steel outer shell positioned around the inner shell while being coaxial therewith to delimit an annular space therewith, the system comprising:
a plurality of mechanical links between the inner shell and the outer shell which are positioned at different intervals of the pipeline;
an electrical and thermal insulation between the inner shell and the outer shell which is positioned over an entire length of the pipeline;
an alternating electric current generator applied between an outer surface of the inner shell and an inner surface of the outer shell over the entire length of the pipeline so as to heat the inner shell of the pipeline by Joule effect;
at least one layer made of resistive and ferromagnetic material positioned on the outer surface of the inner shell over the entire length of the pipeline so as to increase a ratio of electric power transmitted to the inner shell; and
a jacket made of conductive and non-magnetic material positioned on the inner surface of the outer shell over the entire length of the pipeline;
wherein electrical resistivity to magnetic permeability product for the inner shell is increased and electrical resistivity to magnetic permeability product for the outer shell is decreased; and
wherein the jacket is arranged to be split and closed for insertion within the outer shell of the pipeline, and then released once placed in the outer shell to allow the jacket to lie against the inner surface of the outer shell.