Fluid separation assembly and method

An aircraft comprising:

• a fuselage;
• at least one fuel tank mounted to the fuselage;
• at least one fuel tank vent operatively connected to the fuel tank;
• and,
• an inert gas generating system for generating a non-permeate gas on board the aircraft, the inert gas generating system comprising:
• a fluid separation assembly comprising:
• a hollow fiber bundle comprising a plurality of hollow fiber membranes;
• a pair of tubesheets, each encapsulating respective ends of the hollow fiber bundle;
• a plurality of radial through openings formed along a circumference of one or both of the tubesheets and radially through a body portion in one or both of the tubesheets, the plurality of radial through openings comprising both center connected radial through openings and partial radial through openings both formed along the circumference and through the body portion in one or both of the pair of tubesheets, and the plurality of radial through openings intersecting each, or substantially each, of the hollow fiber membranes;
• and,
• a housing surrounding the hollow fiber bundle and the pair of tubesheets, the housing having a feed inlet port, a permeate outlet port, and a non-permeate outlet port, wherein the feed inlet port and the non-permeate outlet port are in parallel alignment with a longitudinal central axis of the housing,
• wherein a feed gas, a permeate gas, or a non-permeate gas are introduced into or removed from the plurality of hollow fiber membranes via the plurality of radial through openings formed in one or both of the tubesheets.

A method for reducing pressure drop in a fluid separation assembly, the method comprising:

• providing a fluid separation assembly comprising:
• a hollow fiber bundle consisting of a plurality of hollow fiber membranes;
• a pair of tubesheets, each encapsulating respective ends of the hollow fiber bundle;
• a housing surrounding the hollow fiber bundle and the pair of tubesheets, the housing having a feed inlet port, a permeate outlet port, and a non-permeate outlet port, wherein the feed inlet port and the non-permeate outlet port are in parallel alignment with a longitudinal central axis of the housing;
• forming a plurality of radial through openings along a circumference of one or both of the tubesheets and radially through a body portion in one or both of the tubesheets, such that the plurality of radial through openings intersect each, or substantially each, of the hollow fiber membranes, and wherein the plurality of radial through openings comprise both center connected radial through openings and partial radial through openings both formed along the circumference and through the body portion in one or both of the pair of tubesheets;
• introducing a feed gas into the fluid separation assembly via the feed inlet port;
• flowing the feed gas through the center connected radial through openings, around the circumference of the one or both tubesheets, and into the partial radial through openings, thereby reducing pressure drop in the fluid separation assembly;
• removing a permeate gas from the fluid separation assembly via the permeate outlet port;
• and,
• removing a non-permeate gas from the fluid separation assembly via the non-permeate outlet port.

A method of generating nitrogen enriched air comprising:

• forming a plurality of radial through openings in a first tubesheet, by cutting or drilling along a circumference of and radially through a body portion of the first tubesheet, the plurality of radial through openings comprising both center connected radial through openings and partial radial through openings, both formed along the circumference and through the body portion of the first tubesheet;
• cutting or drilling the plurality of radial through openings through a first end of a hollow fiber bundle of hollow fiber membranes encapsulated by the first tubesheet;
• introducing a feed gas comprising air, radially through the plurality of radial through openings formed in the first tubesheet;
• permeating a permeate gas comprising one or more of oxygen, carbon dioxide, and water through walls of the hollow fiber membranes;
• and,
• flowing out a non-permeate gas comprising nitrogen enriched air, from an opening of a second tubesheet encapsulating a second end of the hollow fiber bundle of hollow fiber membranes.