Energy Research Institute of The Netherlands ECN, Hydrogen Technologies and Applied Catalysis, Postbus 1, NL-1755 ZG Petten, The Netherlands
Abstract:
The nitric acid industry is a source of both NOx and N2O. The simultaneous selective catalytic reduction of both compounds using propane as a reductant has been investigated. A stacked catalyst bed with first a Co-ZSM-5 catalyst and second a Pd/Fe-ZSM-5 catalyst gives >80% conversion of N2O and NOx above 300 °C at atmospheric pressure. At 4 bar absolute pressure (bara) the Co-ZSM-5 DeNOx catalyst shows higher NOx and propane conversion. This leaves not enough propane for the Pd/Fe-ZSM-5 DeN2O catalyst, which causes a ‘dip’ in N2O conversion. Reducing the space velocity (SV) of the first catalyst bed secures high NOx and N2O conversions from 300 °C and up at 4 bara.