Process Intensification in Nitric Acid Plants by Catalytic Oxidation of Nitric Oxide

Abstract

We have evaluated the kinetics of the catalytic oxidation of NO to NO2 using a Pt/alumina catalyst, under conditions relevant to industrial nitric acid production: NO and steam contents up to 5% and 20%, respectively, with temperatures from 250 to 350 °C, and pressures up to 4.7 bar. The objective is to replace the current homogeneous oxidation process, which requires cooling of the process gas and a long residence time, with a more intensive heterogeneous oxidation process, allowing the heat of reaction (114 kJ/mol) to be recovered. This may give a 10% improvement in overall heat recovery and, additionally, lead to reduced capital expenditure (CAPEX) and footprint of new build plants. With world production of nitric acid of 60 million tonnes per annum, the transformation from the homogeneous oxidation of NO to a heterogeneous oxidation can lead to significant environmental benefits and cost reduction.