Membrane separation technology is a cutting-edge technology rapidly developing worldwide. Its fundamental principle involves the separation of two or more gas mixtures through a polymer membrane. This is due to the varying solubility and diffusion coefficients of gases in the membrane, resulting in different relative permeation rates. Under the driving force of pressure difference across the membrane, gases with relatively fast permeation rates such as water vapor, H₂, He, H2S, CO2, etc., preferentially permeate through the membrane and are enriched. Meanwhile, gases with relatively slower permeation rates such as CH₄, N₂, CO, etc., are enriched on the retentive side of the membrane, achieving the separation of mixed gases.