To inhibit catalyst degradation after a CO selective oxidizer is shut down.
The CO selective oxidizer 14 removes CO gas, which is contained in a hydrogen-rich reformed gas generated in a reformer 1, through an oxidation reaction and is equipped with a double cylindrical main body 19 having an outer cylinder 20 and an inner cylinder 21 that extend vertically and face each other at a prescribed distance, a cylindrical reform gas inlet part 15 that extends downward from the main body 19, an oxidation catalyst layer 22 located inside the inner cylinder 21 and a plurality of moisture-distributing pores 23 formed in a dispersed manner on a peripheral wall of the inner cylinder 21. When the CO selective oxidizer 14 is shutdown, the outer cylinder is cooled before the inner cylinder so that moisture-containing gas flows into the outer cylinder through the moisture-distributing pores, condenses on its inner wall, flows down the inner wall and is discharged into the reform gas inlet, and a portion of the condensed water formed thereby directly flows down to a bottom of the inner cylinder 21 and is discharged into the reform gas inlet part 15.
COPYRIGHT: (C)2008,JPO&INPIT
YOSHINO YASUSHI
ONO JUN
FUJISHIMA SHIRO
MOROISHI TAKUYA
