Experimental Research On Compact SCR For Reducing NO_x Emission

Ammonia selective catalytic reduction?SCR?is the most widely used and most efficient technology for NOx emission reduction.In this paper,The Compact SCR technology——combined with NO catalytic oxidation and SCR Technology was investagated,to control the emissions of nitrogen oxides from marine diesel engine.A series of Ru-based catalysts for NO oxidation were prepared by impregnation method.The effects of support,active component loading,calcination temperature and the modification of additive on the activity of the catalyst were investigated.The results showed that the catalyst prepared with TiO₂,and calcined at 450?exhibited the best activity.Considering the price and rare degree of precious metals,the Ru load is 0.5%.Additive?Ce?La?Pr?Ni?W?Mo?V?Sb?Cr?is no helpful for the activity of 0.5Ru/TiO₂ catalyst at low temperature.The influences of flue gas temperature,O₂content,NO content,space velocity and SO₂ were investigated.Experimental results showed that Ru/TiO₂ catalysts were susceptible to SO₂ poisoning,The activity decreased rapidly with the increase of time.A series of Cr-based catalysts for NO oxidation were prepared by impregnation method.The 10%Cr/TiO2?calcined at 350?catalyst exhibited the best activity.Adding Sb to 10Cr/TiO₂ catalyst,The result shows that 10Cr10Sb/TiO2 exhibited the best activity,it improves the NO oxidation activity at low temperature——NO conversion of 50%at 260?.Sulphur resistance test for 10Cr10Sb/TiO₂ catalyst shows that it has resistance to sulfur at 350?.In order to investigate the NO removal efficiency of compact SCR,10Cr10Sb/TiO₂ catalyst was selected as NO catalytic oxidant and V₂O₅/TiO₂ catalyst?made by laboratory?as SCR catalyst.The influence of NO oxidation rate and space velocity on compact SCR denitration efficiency is also investigated.The results show that the NO removal efficiency of compact SCR is greatly improved compared with standard SCR when the oxidation rate of NO is 46%.