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

Chapter 44.4.10 Combination of SCR and wet catalysisDescriptionExamples of such processes are the SNOX process and the Desonox process.After particulates removal with a fabric filter or an electrostatic precipitator, the flue-gas isheated in heat exchanger. In the catalytic DeNO x system, the nitrogen oxides in the flue-gas arereduced selectively with ammonia to yield nitrogen. In the subsequent SO 2 converter, the SO 2 isoxidised catalytically to SO 3 , which is recovered in a condenser as concentrated sulphuric acid.Ambient air preheated in the condenser is used as combustion air for the boiler. The combinedSCR/wet catalysis plant can be fully automated and can be operated from the main control roomof the power plant without requiring additional manpower. There is no hold-up of liquids orsolids and response to variations in boiler load is very fast.Achieved environmental benefits• enables the direct production of H 2 SO 4 from SO 2 in flue-gases• recovery of 95 % of the sulphur content from the flue-gas.Cross-media effectsNH 3 consumption.Operational dataNo specific information provided.ApplicabilityApplicable to low SO 2 content gases with high volume flows. Usually applied to tail gases fromthe combustion of fuels containing sulphur. The process is adaptable to new or to retrofitinstallations.EconomicsNo specific information provided.Driving force for implementationLower SO 2 emissions. Cost benefits from selling the co-product H 2 SO 4 can be assumed.References to literature and example plants[57, Austrian UBA, 2001, 66, Haldor Topsoe, 2000]188 Large Volume Inorganic Chemicals – Ammonia, Acids and Fertilisers