| 摘要 |
The present invention relates to a method and a catalyst composite useful for reducing contaminants in exhaust gas streams, especially gaseous streams containing sulfur oxide contaminants. More specifically, the present invention is concerned with a method for removing NOX and SOX contaminants from a gaseous stream comprising providing a catalyst composite having a downstream section and upstream section. The downstreams section comprises a first support, a first platinum component, and a NOX sorbent component. The upstream section comprises a second support, a second platinum component, and a SOX sorbent component selected from the group consisting of oxides of Mg, Zn, Mn, Fe, and Ni. In a sorbing period, a lean gaseous stream comprising NOX and SOX is passed within a sorbing temperature range through the upstream section to sorb at least some of the SOX contaminants and thereby provide a SOX depleted gaseous stream exiting the upstream section and entering the downstream section. The downstream section sorbs and abates the NOX in the gaseous stream and thereby provides a NOX depleted gaseous stream exiting the downstream section. In a SOX desorbing period, the lean gaseous stream is converted to a rich gaseous stream and the temperature of the gaseous stream is raised to within a desorbing temperature range to thereby desorb and abate at least some of the SOX contaminants in the upstream section and thereby provide a SOX enriched gaseous stream exiting the upstream section and entering the downstream section. The desorbing temperature range is sufficiently high such that the SOX contaminant are substantially not sorbed in the downstream section. |
