Development of a Resource-Saving Technology of Catalysts for Medium-Temperature Conversion of Carbon Monoxide in Ammonia Production

Abstract

The physicochemical characteristics of modern catalysts for the medium-temperature conversion of carbon monoxide to hydrogen in the production of ammonia were studied by X-ray diffraction, scanning electron microscopy, gas chromatography, and thermogravimetric and laser dispersion analyses. It was shown that, along with iron oxide, the catalysts contained promoter additives of Cr, Cu, Ca, and Mn compounds in a total concentration of 1–9 wt%. The investigated commercial catalysts have a monodisperse porous structure with a pore size of up to 10 nm and a large surface area from 70 to 120 m2/g. The catalytic activity of the samples was estimated by the conversion of CO in a flow-type plant. At 2.2 MPa and 340 °C it was 89–91%. The drawback of the catalysts was that the condensate contained rather much ammonia (27.6–45.6 mg/L). It was established that using calcium and copper ferrites and nickel oxide as promoters makes it possible to obtain a catalyst that is not inferior in activity to commercial analogs but has a higher selectivity by reducing the ammonia content of the condensate by 20–30%.