Cu-CHA/Fe-MFI mixed zeolite catalyst and process for the treatment of NO_xin gas streams

摘要

Described is a catalyst, preferably for use in selective catalytic reduction (SCR), said catalyst comprising one or more zeolites of the MFI structure type, and one or more zeolites of the CHA structure type, wherein at least part of the one or more zeolites of the MFI structure type contain iron (Fe), and wherein at least part of the one or more zeolites of the CHA structure type contain copper (Cu). An exhaust gas treatment system is described, comprising said catalyst as well as a process for the treatment of a gas stream comprising NOx using said catalyst as well.

主权项

1. A catalyst for use in selective catalytic reduction (SCR), said catalyst comprising:
one or more zeolites of the MFI structure type, and one or more zeolites of the CHA structure type, wherein at least part of the one or more zeolites of the MFI structure type contain iron (Fe), wherein at least part of the one or more zeolites of the CHA structure type contain copper (Cu), wherein the weight ratio of the one or more zeolites of the MFI structure type relative to the one or more zeolites of the CHA structure type ranges from 1:2 to 2:1, wherein the molar ratio of silica to alumina (SAR) in the one or more zeolites of the MFI structure type ranges from 20 to 50, wherein the molar ratio of silica to alumina (SAR) in the one or more zeolites of the CHA structure type ranges from 20 to 55, wherein the amount of Fe in the one or more zeolites of the MFI structure type ranges from 2.5 to 5.5 wt-% based on the weight of said one or more zeolites, and wherein the amount of Cu in the one or more zeolites of the CHA structure type ranges from 1.0 to 1.0 wt-% based on the weight of said one or more zeolites.