NOVELTY - A reformer system (100) comprises an exhaust treatment device; reformer (20) disposed upstream of and in fluid communication with the exhaust treatment device, where the reformer is capable of producing reformate containing hydrogen and optionally carbon monoxide; either oxygen storage device (24) disposed upstream of and in fluid communication with the reformer or reformate storage device disposed downstream of and in fluid communication with the reformer; and fluid moving device (26) disposed upstream of and in fluid communication with the oxygen storage device/reformate storage device.    USE - As a reformer system (claimed) in fuel cell systems such as solid oxide fuel cell system and proton exchange membrane system; in internal combustion engine system such as engine system fueled with diesel fuel and gasoline; and in chemical processes employing hydrogen as reactant.    ADVANTAGE - The storage device having reduced size reduces equipment cost, peak power budget and operating costs associated with the reformer system. The system allows oxygen to be stored under pressure in the oxygen storage device, and dispersed on demand to the reformer; can provide a reduction in the size, mass, and peak power budget of at least the first fluid moving device compared to systems that do not employ an oxygen storage device; has reduced equipment costs and operating (power) costs. The system allows greater than 50% reduction in the size of a reformer substrate as compared to systems that do not operate continuously and/or do not employ a reformate storage device that is capable of storing reformate under pressure.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for operating a reformer system involving: generating an exhaust gas; treating the exhaust gas in an exhaust treatment device; generating reformate in a reformer disposed in fluid communication with the exhaust treatment device, where the reformate comprises hydrogen and carbon monoxide; storing the reformate under pressure in a reformate storage device disposed downstream of and in fluid communication with the reformer; and releasing reformate from the reformate storage device to regenerate the exhaust treatment device.    DESCRIPTION OF DRAWING(S) - The figure shows schematic illustration of reformer system.    exhaust gas source (12)    in-line oxidation catalyst device (14)    adsorber device (16)    filter (18)    reformer (20)    exhaust conduit (22)    oxygen storage device (24)    first fluid moving device (26)    reformer system. (100)