Large Volume Inorganic Chemicals - Ammonia ... - ammk-rks.net

Chapter 3Operational dataVarious catalysts are actually available, e.g.1. Catalyst developed by Yara [109, Lenoir, 2006]:• cerium oxide-based catalyst with cobalt as the active component• multicored cylindrical pellets 9 x 9 mm• bulk density of 1.1 – 1.3 g/m 3• radial crushing strength >20 Newton• increasing efficiency with increasing pressure and temperature• no losses in NO yield.2. Catalyst developed by BASF [111, NCIC, 2004, 149, BASF, 2006]:• various types available, “O3-85”-types• composition (w/w): CuO 20 %, ZnO 16 %, plus Al 2 O 3 and promoters• various shapes• operational for low, medium and high pressure oxidation• no measurable loss in NO yield.3. Catalyst developed by Heraeus [113, Sasol, 2006, 116, Jantsch, 2006]:• precious metal deposited over ceramic• no measurable effect on NO yield• N 2 O level adjustable by variation of the catalyst layer thickness.ApplicabilityApplicable to new and existing plants. Table 3.12 shows example plants.In atmospheric pressure plants, the extra pressure drop in the reactor reduces the plant capacity[149, BASF, 2006].Depending on the particular case, limitations for the application of a N 2 O decompositioncatalyst might arise with respect to the following factors [149, BASF, 2006]:• some plants might require modifications to build in a basket• basket design and actual basket condition• available height in the burner basket for filling with a De-N 2 O catalyst, heights might varyfrom about 5 – 14 cm• potential for gas slip at the reactor wall• gas temperature, pressure and velocity• additional pressure drop, depending on the catalyst size and shape• additional load on the statics of the reactor through added weight and additional pressuredrop.Economics• additional costs for the catalyst• easy and cost-effective to install, using the existing basket without any further modifications• an NO x abatement system is still required in most cases.124 Large Volume Inorganic Chemicals – Ammonia, Acids and Fertilisers