Performance of Fe-Ni-W exchanged zeolite for NOx reduction with NH3 in a lab-scale circulating fluidized bed

Selective non-catalytic reduction of NOx (SNCR) with NH3 is commonly used in industrial facilities like circulating fluidized bed (CFB) furnaces. However, the strongly temperature-dependent de-NOx feature confines its applications in a specific temperature range (900-1050 degrees C). Here, we report a new strategy on using Fe-Ni-W exchanged zeolite (0.5FNW-H) as a catalyst to extend the SNCR temperature window. In the CFB reactor, a significant NOx conversion improvement ranging from 14.1% to 80.9% was achieved at 700 to 850 degrees C by applying the developed catalyst. Catalyst dosage of 4500 h(-1) (GHSV), a particle diameter of 0.1-0.3 mm, and NH3 injection position at the dense-phase zone were found preferred for NOx reduction with the highest efficiency of similar to 85% at 700 degrees C. The physicochemical properties of the catalysts remained stable after the circulating reactions in the CFB reactor. The developed catalyst is particularly applicable for improving the SNCR performance when the thermal power plants are operated at low loads.

Automated summary

A new catalyst (Fe-Ni-W exchanged zeolite) has been reported to extend the application range of SNCR at lower temperatures, increasing NOx conversion rates. Optimization of catalyst usage conditions has led to achieving maximum efficiency at 700 degrees Celsius.