Dual bed catalytic system for the reduction of NOx

Abstract

The present invention relates to a dual bed catalytic system for the reduction of nitrogen oxides comprising silver-deposited alumina (Ag/Al 2 O 3 ) and zeolite (ZSM-5). The present dual bed catalytic system provides significantly improved NOx reducing efficiency as compared to the system using Ag/Al 2 O 3 or ZSM-5.

1 . A dual bed catalytic system for the reduction of nitrogen oxides (NO x ), which comprises:
 alumina-supported silver (Ag/Al 2 O 3 ) comprising 1-5 wt % of silver (Ag) and 95-99 wt % of alumina (Al 2 O 3 ); and   zeolite (ZSM-5) comprising 0-5 wt % of copper (Cu) and 95-100 wt % of zeolite (ZSM-5).   
   
   
       2 . The dual bed catalytic system as set forth in  claim 1 , wherein the Ag/Al 2 O 3  and the ZSM-5 are packed. 
   
   
       3 . The dual bed catalytic system as set forth in  claim 1 , wherein the ZSM-5 is a copper (Cu) deposited ZSM-5. 
   
   
       4 . The dual bed catalytic system as set forth in  claim 1 , wherein ratio of the Ag/Al 2 O 3  and the ZSM-5 is from 4:1 to 1:4 based on weight. 
   
   
       5 . The dual bed catalytic system as set forth in  claim 1 , wherein the Ag/Al 2 O 3  is located at the front part of the system and the ZSM-5 is located at the rear part of the system. 
   
   
       6 . The dual bed catalytic system as set forth in  claim 1 , which comprises a C 6 -C 16  hydrocarbon compound as a reductant of NO x .