The Efficiency of Fe/MFI Additives in Reducing NOx in Cracking Catalyst Regeneration Flue Gas

A series of additives based on an iron-modified MFI zeolite were investigated for their ability to reduce NOx in cracking catalyst regeneration flue gases. Their efficiency was dependent on the iron loading, the zeolite SiO2/Al2O3 ratio, and the initial cationic form used for modification. The Fe/MFI additives prepared from an NH4-form zeolite with a low SiO2/Al2O3 ratio (23) demonstrated excellent performance. Under industrially relevant catalyst regeneration conditions, the additive with an optimized iron oxide content (within a tested range of 0.5 to 2.5 wt %) reached a NOx reduction efficiency of 45.4%.