Gas separation membrane cartridge with clamshell retainer

A cartridge for non-cryogenically separating a gas into components includes a plurality of hollow polymeric fibers, the fibers being anchored by a pair of tubesheets, each tubesheet being adjacent to a head, the tubesheet and head being joined by a clamshell retainer. The cartridge does not have a core tube. The fibers are enclosed within a sleeve, the sleeve being sufficiently thin so as to be a non-structural element. The cartridge may be inserted within a larger pressure vessel. The cartridge of the present invention can accommodate more fibers than comparable cartridges of the prior art, and therefore has greater throughput.