For this purpose, a partial flow of the sintered exhaust gas was branched off and fed to an experimental installation. On the basis of the findings of the pilot tests the design of the large-scale DeNOx plant was carried out. This works as follows: the sintering gas coming from the MEROS system (Maximized Emission Reduction Of Sintering) flows in the first step via a heat exchanger, whereupon it is then heated to 280 ° C. by means of a gas burner. Subsequently, ammonia is injected before the exhaust gas flows through the catalyst plane. The nitrogen oxides (NOx) are reduced to harmless nitrogen (N2) and water (H20). This method is called SCR (selective catalytic reduction).
The plant has been in operation since December 2012 and initial experiences and results show that the investment contributes significantly to environmental protection. By commissioning the denitrification plant, the nitrogen oxides can be reduced by a further 400 tonnes per year, which is more than 10% of the annual 3,600 tonnes of nitrogen oxide emissions and about one third of the total nitrogen oxide emissions of the sinter plant. The system is already attracting great interest internationally.
Nitrogen oxides (NOx) are gaseous nitrogen compounds. They are generated during combustion processes in motor vehicles, power plants and in industry as well as microbiological degradation processes in the soil. Also open fire (gas stove, candles) and smoking cause NOx. Nitrogen oxides irritate and injure the respiratory organs, form aggressive ground-level ozone and greenhouse gases. The main cause for NOx is road traffic, especially diesel engines.