Operating principle of membrane systems is based on the difference in gas components penetration rates through membrane substance. The driving force of the gas separation process is the diffidence in partial pressures on the membrane sides. The hollow-fiber membrane used by LGM consists of porous polymer fiber with the gas separation layer applied to its outer surface.

Structurally, a hollow-fiber membrane is configured as a cylindrical cartridge representing a spool with specifically reeled polymer fibers. Gas flow is pressurized into the bundle of membrane fibers. Separation of the gas mixture is achieved through the difference in partial pressures on the external and internal surfaces of the hollow-fiber membrane. ”Fast” gases easily penetrating the polymer membrane(e.g.H2、CO2 O2.water vapors)penetrate the fibers and exit the membrane cartridge through one of the outlet fittings. “Slow” gases, taking time to penetrate the membrane(e.g. CO,N2,CH4, Higher hydrocarbons)exit the membrane module through a second outlet fitting.