NOVELTY - Removing a target gas component from a gas mixture (837) containing target gas and product gas components involves: conducting gas mixture to a turboexpander (821); conducting the lowered pressure gas mixture to a swing adsorption gas separation unit (841) having an adsorbent contactor; producing a product gas stream (815) having lower mol.% of target gas component and higher mol.% of product gas component than the mixture; collecting the product gas stream, desorbing a portion of adsorbed target gas component; and collecting waste gas stream (895).    USE - For removing a target gas component i.e. carbon dioxide, nitrogen or hydrogen sulfide from a gas mixture containing the target gas component and a product gas component i.e. methane (claimed).    ADVANTAGE - The process allows to recover methane more efficiently, at lower costs, and at higher yields. The process provides improvements in the recovery of methane from a gas mixture and removes impurities from natural gas streams, particularly high pressure natural gas streams and recover the methane-rich product stream at as high a pressure as practical for operability in natural gas processing. The process allows purification of high pressure gaseous streams, such as high-pressure natural gas streams containing significant amounts of CO2 and increases the recovery of the light component i.e. methane by conditioning the temperature and pressure of the gas fed to the contactor. This method can be used with or without a contactor having a low volume fraction of mesopores and macropores. Moreover, the process can be applied to improve the separation of molecular species from synthesis gas.    DETAILED DESCRIPTION - Removing a target gas component from a gas mixture (837) containing the target gas component and a product gas component involves: conducting the gas mixture to a turboexpander (821) where the volume of the gas mixture is expanded, thus lowering its pressure; conducting the lowered pressure gas mixture from the turboexpander to a swing adsorption gas separation unit (841) where the gas separation unit contains an adsorbent contactor comprised of an effective microporous adsorbent material for removing at least a portion of the target gas component from the gas mixture by adsorbing at least a portion of the target gas component onto the adsorbent material; producing a product gas stream (815) with a lower mol.% of the target gas component than the gas mixture and a higher mol.% of the product gas component than the gas mixture; collecting the product gas stream; desorbing at least a portion of the adsorbed target gas component from the adsorbent material, resulting in a waste gas stream which has a higher mol.% of the target gas component than the gas mixture; and collecting the waste gas stream (895).    DESCRIPTION OF DRAWING(S) - The figure shows a schematic diagram of an integrated process utilizing a turboexpander and a pressure swing adsorption process.    Product gas stream (815)    Turboexpander (821)    Gas mixture (837)    Swing adsorption gas separation unit (841)    Waste gas stream (895)