Study On Denitrification Performance Of Carbon Based Carrier Composite Catalyst

NH₃-SCR is one of the most widely used and effective method to remove NOx.However,the dust,SO₂ and water vapor contained in the flue gas would affect the denitrification process with high temperature of 350?⁴50?.There are a series of problems in waste gas treatment with Vanadium-titanium denitrification catalysts,such as leaching toxicity and other dangerous characteristics.So low-temperature,environmental-friendly SCR catalysts have attracted a broad attention with higher efficiency and good resistance.In this paper,the different compositions of Mn/AC catalysts were studied,and the effects of Fe,Ce and Cu on the denitrification efficiency and sulfur resistance of Mn/AC catalysts were compared.Through characterization and analysis of the specific surface area,particle size,component crystal ine phase and element morphology of the catalyst,the modification rules of different metals on the catalyst were discussed.At the same time,the optimum composition ratio and preparation methods were obtained.The economic analysis of the catalysts provided the support for the selection of catalyst carrier and active components in the future.The specific conclusions were as follows:The volume fraction of NO,NH₃,O₂ in simulated flue gas were 0.1%,0.1%,8%respectively,and high purity N₂ was used as equilibrium gas under the airspeed of 8000h^-1.Mn/AC had good denitrification activity,and the highest denitrification efficiency of87.12%was obtained at 200?with the loading of 10 wt.%Mn.The addition of Fe,Ce and Cu based on Mn/AC improved the denitrification efficiency and sulfur resistance?Fe>Ce>Cu?.It showed a better modified effect when the loading of Fe was 15 wt.%.The denitrification efficiency of Fe?15?Mn?10?/AC catalyst was 67.17%at 80?,and a higher denitrification efficiency of 99.81%was realized with Fe?15?Mn?10?/AC at 200?.Characterized by means of SEM,BET,XRD,the addition of appropriate amount of metals could increase the specific surface area and ful y contact with the treated gas which was contributed to enhance the denitrification efficiency.The Mn/AC catalyst had a bad sulfur resistance.The denitrification efficiency of the Mn/AC was only 5.70%after the ventilation with SO₂.Under the influence of SO₂,ammonium bisulfate and ammonium sulfate would be formed on the surface of the catalyst during the denitrification process.Those agglomerate particles could block catalyst channels and reduce denitrification efficiency.At the same time,the decomposition temperature of ammonium bisulfate and ammonium sulfate was rather high,it was difficult to remove them at low temperature,which resulted in the irreversible deactivation of low temperature catalyst.Compared pure Mn/AC with those of Mn/AC modified by other metals,the modified Mn/AC had a better denitrification efficiency.The sulfur resistance was in the order of Fe>Cu>Ce.Influenced by SO₂,the denitrification efficiency of the Fe?15?Mn?10?/AC catalyst was 70.50%.The catalyst activity could recover after the regeneration process for sulfur resistant catalyst,the denitrification efficiency of the Fe-Mn?r?/AC catalyst was 99.8%.Through the economic analysis of catalyst cost,Fe?15?Mn?10?/AC spent the lowest cost in the series of catalysts?Ce>Mn>Cu>Fe?.Among the economic cost components of catalysts,active sites accounted for the largest proportion about 71%of the total cost,followed by carriers and binders.It found that the active sites with low price and good catalytic performance for denitrification should be selected in controlling the cost of catalysts.