Simulation of N2O abatement in waste gases by its decomposition over a K-promoted Co-Mn-Al mixed oxide catalyst

Abstract

Intrinsic data of N2O catalytic decomposition over a K-promoted Co-Mn-Al mixed oxide prepared by the thermal treatment of a layered double hydroxide was used for the design of a pilot reactor for the abatement of N2O emissions from the off-gases in HNO3 production. A pseudo-homogeneous one-dimensional model of an ideal plug flow reactor under an isothermal regime (450 °C) was used for reactor design. A catalyst particle diameter of 3 mm is a compromise size because increasing the size of the catalyst particle leads to a decrease in the reaction rate because of an internal diffusion limitation, and particles with a smaller diameter cause a large pressure drop. A catalyst bed of 11.5 m3 was estimated for the target N2O conversion of 90% upon the treatment of 30000 m3/h of exhaust gas (0.1 mol% N2O, 0.005 mol% NO, 0.9 mol% H2O, 5 mol% O2) at 450 °C and 130 kPa.