N2O catalytic decomposition – From laboratory experiment to industry reactor

Paper deals with design of pilot reactor for low temperature N2O decomposition in off-gases from HNO3 production. Pseudo-homogeneous one-dimensional model of an ideal plug flow reactor was used for modeling of N2O decomposition in a laboratory fixed bed reactor filled with grains or pellets of a Co–Mn–Al mixed oxide catalyst. Increase in inlet pressure up to 0.6 MPa did not influence the effective diffusion coefficient, but improved the achieved N2O conversion. Based on the laboratory data of N2O decomposition over Co–Mn–Al mixed oxide pellets, catalyst bed of 3400 kg was estimated for target 90% N2O conversion (30 000 m3 h−1 of exhaust gases from HNO3 plant containing 0.1 molar% N2O, 0.01 molar% NO, 0.01 molar% NO2, 3 molar% H2O, 5 molar% O2) at 420 °C and 600 kPa inlet pressure.

Graphical abstractCo–Mn–Al mixed oxide catalyst derived from layered double hydroxide was used to estimate the size of N2O decomposition reactor used for the exhaust gas purification in the nitric acid production unit.Figure optionsDownload full-size imageDownload high-quality image (170 K)Download as PowerPoint slideHighlights► N2O decomposition in simulated off-gas from HNO3 plant. ► Co–Mn–Al mixed oxide catalyst as grains or pellets. ► Pseudo-homogeneous one-dimensional model of N2O decomposition in fixed bed. ► Increase in inlet pressure up to 0.6 MPa improved the N2O conversion. ► Design of pilot reactor for N2O emissions abatement from HNO3 plant.