Subsea fluid processing system having a canned motor stator filled with a dielectric fluid

A subsea process fluid processing system, comprising:

• an inlet;
• an outlet;
• an elongated impeller shaft;
• a set of impellers fixedly mounted to the elongated impeller shaft and positioned between the inlet and the outlet, the set of impellers configured to increase pressure of a process fluid when the elongated impeller shaft is rotated;
• an electric motor configured to impart torque on the elongated impeller shaft thereby causing the elongated impeller shaft to rotate about a main longitudinal axis, the electric motor comprising:
• a rotor fixedly mounted to the elongated impeller shaft;
• and
• a canned fluid filled stator, dimensioned and positioned to surround the rotor, and being filled with a dielectric stator fluid and sealed at least with a canning of non-metallic material on an inner surface facing the rotor;
• a plurality of radial bearings coupled to the elongated impeller shaft;
• a balance piston coupled to the elongated impeller shaft;
• wherein, during operation, a first fluid passes between the inner surface of the canned stator and the rotor, the first fluid being sourced, at least in part, from the process fluid comprising sea water in which the system is submerged;
• and
• a vent open to an outside environment through which the first fluid may pass, wherein the plurality of radial bearings and the balance piston are in fluid communication with the vent, such that the process fluid contacts the plurality of radial bearings and the balance piston.