Fuel oxygen reduction unit with bleed driven boost impeller

A fuel delivery system for a gas turbine engine comprising:

• a fuel source;
• a draw pump downstream of the fuel source for generating a liquid fuel flow from the fuel source;
• a main fuel pump downstream of the draw pump;
• and
• a fuel oxygen reduction unit downstream of the draw pump and upstream of the main fuel pump, the fuel oxygen reduction unit comprising:
• a stripping gas line;
• a contactor in fluid communication with the stripping gas line and the draw pump for forming a fuel/gas mixture, wherein the contactor receives an inlet fuel flow from the draw pump;
• a separator in fluid communication with the contactor, the separator receives the fuel/gas mixture and separates the fuel/gas mixture into an outlet stripping gas flow and an outlet fuel flow at a location upstream of the main fuel pump;
• an impeller disposed downstream of the separator and upstream of the contactor, wherein the impeller circulates a stripping gas to the contactor;
• and
• a turbine coupled to the impeller.

A method for operating a fuel delivery system comprising:

• using a fuel oxygen reduction unit to reduce an oxygen content of a fuel flow through the fuel delivery system, wherein using the fuel oxygen reduction unit comprises
• operating a gas pump in fluid communication with a stripping gas flowpath of the fuel oxygen reduction unit at a first speed;
• and
• operating a separator in fluid communication with the stripping gas flowpath of the fuel oxygen reduction unit and a fuel flowpath of the fuel delivery system at a second speed that is different than the first speed.