Catalytic removal of N2O in model flue gases of a nitric acid plant using a promoted Fe zeolite

Three options for removal of N2O using a promoted Fe-ZSM-5 catalyst have been explored under conditions representative for the off gases of a nitric acid plant: catalytic decomposition and selective catalytic reduction (SCR) using propane or methane as a reductant. Catalytic decomposition of N2O takes place at temperatures above 400°C at a space velocity of 10,000 h−1. The addition of propane lowers the temperature for N2O conversion with about 100°C. In propane-assisted SCR of N2O, the emissions of unreacted hydrocarbons and of CO are low and also NOx reduction takes place. Methane is more difficult to be activated by the catalyst, which causes lower N2O destruction efficiency and the output of unreacted methane. In all cases, N2O conversion is higher at elevated pressure.