TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Method: A majority of carbon dioxide in the feed gas inlet stream is adsorbed by the first and second adsorbent beds during the first and second feed/purge steps, respectively. The adsorbed carbon dioxide is removed from the first and second adsorbent beds by the purge gas inlet stream during the second and first feed/purge steps, respectively. The removed carbon dioxide is collected with the purge gas outlet stream at the second output during the second and first feed/purge steps. Carbon monoxide is collected together with hydrogen at the first output. A portion of water vapor in the feed gas inlet stream is adsorbed by the first and second adsorbent beds during the first and second feed/purge steps, respectively. The adsorbed water vapor is removed from the first and second adsorbent beds by the purge gas inlet stream during the second and first feed/purge steps, respectively. The removed water vapor is collected with the purge gas outlet stream at the second output during the second and first feed/purge steps. The feed gas inlet stream is not pressurized prior to being provided into the first and second adsorbent beds. In the first and second flush steps, the feed gas outlet stream is collected at the second output; and in the second feed/purge step, the purge gas outlet stream is collected at the second output. The duration of first and second feed/purge steps is greater than or equal to5 times as long as the duration of first and second flush steps.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Gases: The feed gas inlet stream comprises hydrogen, carbon dioxide, carbon monoxide and water vapor. The feed gas inlet stream may comprise portion(s) of a fuel exhaust stream from a solid oxide fuel cell stack. The purge gas inlet stream comprises air having less than or equal to50% relative humidity or dried air of less than or equal to50% relative humidity which has been dried using third and fourth adsorbent beds. The separated component collected at the first output comprises hydrogen. Preferred Adsorbent: The adsorbent material of first and second adsorbent beds is zeolite, silica gel, activated alumina, or preferably activated carbon.