Technical Engineering for Catalytic Reduction of Nitrous Oxide Emissions

Abstract

Production of nitric acid is the major emission source of the greenhouse gas nitrous oxide N2O. High temperature catalytic decomposition of N2O by installing a secondary catalyst has been applied at a nitric acid plant in Devnya, Bulgaria. A reconstruction of the ammonia burning reactors was done in august 2012 in order to increase the thickness of the secondary catalyst layer from 28 mm to 60 mm. Nitrous oxide concentration has been monitored for 5 year period – from 2010 to 2014. Monitoring results indicate that the effectiveness of N2O catalytic decomposition depends on the thickness of the secondary catalyst layer - increasing the layer thickness twice leads to over 60 % reduction of the maximum registered and annual average concentrations of N2O. Increasing the thickness of the secondary catalyst layer enhances the effectiveness of high temperature N2O decomposition, which is essential for the parties to the United Nations framework convention on climate change and the Kyoto protocol regarding the fulfillment of their quantitative commitments for greenhouse gas emission reduction.