Abstract: An apparatus for purifying and liquifying an input gas containing natural gas and air. The apparatus comprises a plurality of molecular sieve assemblies operatable to clean the gas on a gas cleaning mode and to be regenerated on a heating mode and a cooling mode. A first assembly cleans the gas while a second sieve assembly is being regenerated. A three position valve associated with each molecular sieve assembly changes the modes of the sieve assemblies. A two position valve supplies hot air for heating the sieve assemblies during the heating mode, supplies cool air for cooling the sieve assemblies when the sieve assemblies are at a temperature above 400.degree. F. and supplies cool gas for cooling the sieve assemblies when the sieve assemblies are at a temperature below 400.degree. F.

Abstract: An apparatus and a process for cleaning and liquifying an input gas. An engine operates on a portion of cleaned gas and discharges exhaust gases. A heat exchanger transfers heat from the exhaust gases to the portion of the cleaned gas. Apparatus for liquifying the cleaned gas is powered by the engines. Molecular sieves clean the input gas to produce the cleaned gas and are regenerated by the portion of the cleaned gas.