"elemento de membrana para tratar uma corrente de gás natural"

A membrane filter element includes at least two cylindrical-shaped, fiber bundles, one of the fiber bundles containing first fibers fabricated to provide a selected first gas selectivity, a selected first gas permeability, or a selected first gas selectivity and permeability performance and arranged so a first gas permeate exits the membrane element; another of the fiber bundles containing second fibers fabricated to provide a selected second, different gas selectivity, a selected second different gas permeability, or a selected second gas selectivity and permeability performance and arranged so a second different gas permeate exits the membrane element. The different performance characteristics can reduce the number of membrane elements required for gas separation and to improve gas separation performance due to changing gas composition as the gas travels through the membrane element.