The Experimental Study Based On Catalytic Removal NO From Flue Gas In A Novel Fluidized Reactor

The nitrogen oxide （NOx） is one of the main atmosphere pollutants in ourcountry, and its most important source is the emission of coal-fired power plant.The NOxcan not only cause various environmental problems including acid rain,photochemical smog and ozone depletion,but also imposes seriously threat on people’shealth and the ecological environment. Selective Catalytic Reduction （SCR） use NH₃as reductant is currently the most widely used denitrification technology in coal-firedpower plant.While the preparation of SCR catalyst is the core of the technology. SCRreactor in Low temperature NH₃-SCR technology can be arranged at the back of thedust removal and desulfurization in order to avoid the toxic effects of smoke and SO₂,and this technology is more practical, effective and easy to popularize. Therefore, theresearch and development of SCR catalyst with high efficiency and stable performanceat low temperature has become a hot topic in the research of the technical field.Choosing a suitable low temperature catalyst is the most important part of SCR.In MnO_x, there are plenty of lattice oxygen which are benefical to the redox reaction.Mn is considered to have a very prominent low-temperature catalytic property, andAnd research results show that the effect of composite catalyst is better than any singlecomponent. In the practical application, the MnO_x is often be set on the surfce of othermetallic oxide to produce MnO_x/TiO₂, MnO_x/γ-Al₂O₃. So, it is a great significance ofresearching and developing a high performance Mn based catalyst.First of all, this thesis point at the preparation conditions of Mn-based catalystcarrier. The experiments using sol-gel to prepared MnO_x/γ-Al₂O₃MnO_x/TiO₂, andfilter catalyst carrier which is suitable to load MnO_x by characterization anddenitrification experiment.After analysising the result of test,it is turn out thatphysical and chemical properties of MnO_x/γ-Al₂O₃and MnO_x/TiO₂catalyst havetheir own advantages, anyway, denitrification experiment also proves that TiO₂is more suitable as a carrier for MnO_xcatalyst under the condition of low temperature.Next,three groups of Mn catalysts were prepared in the experiment.It is researched theinfluence of MnO_x loading amount（Mn/Ti=0.2,0.3,0.4,0.5）, the calcinationtemperature （450℃,500℃,550℃,600℃）, and different additives （Ce, Cu,Fe,Ni）on the surface properties and denitrification activity of catalysts.In the wholetemperature range,the result show that when the Mn/Ti ratio is0.4, the catalyst have abest performance on surface properties and denitration efficiency;500℃is the mostsuitable calcination temperature of Mn-based catalyst;In the four kinds of additivesdoped catalysts, the performance of MnO_x-Ce/TiO₂catalyst is particularly prominent,so, the transition metal doped Mn-based catalyst has broad prospects.In the end, denitration experiment was carried out by using the self-made newtype fluidization reactor, and screened excellent working conditions. At the same time,this paper made preliminary study on the reaction kinetics model of fluidized reactor.The active test of MnO_x/TiO₂has studied under the different temperature and thedifferent speed of flow and the different oxygen concentration, to study the conversionof NOx. The results will further optimization of SCR reaction conditions. When thereaction temperature reached180℃, the activity of the catalyst gradually achieve thebest state;The entrance of the flue gas flow rate is smaller, the greater the conversionrate of the catalyst for NO. When the entrance speed of flow establishment is800mL/min, the NOx conversion rate could reach93.8%. When the concentration ofO₂is lower than800ppm, O₂has great effect on the denitrification activity. When theO₂concentration is higher than800ppm, the influence of O₂concentration can beignored.