Study On High Efficiency Removal Of NO By Microwave Catalytic At Low Temperature

NOx is the primary air pollutant and the main reason of the formation of photo-chemical smog and acid rain.It can directly combine with haemoglobin and results in ills of respiratory system.The emitted amount of NOx is also tremendous though the emitted of NOx is controlled by government in recent years.Eco-system and human health are seriously threatened by NOx in exhaust gas.Therefore,efficiently removal of NOx has become a key project in atmospheric environmental protection.Selective catalytic reduction and direct catalytic decomposition are the most interesting denitration methods.NH3-SCR is the most widely used denitrification technology in industry.However,there are still some problems such as narrow reaction temperature range,risk of storage and transportation of reducing agent NH3,secondary pollution,and formation(NH4)2SO4 in the presence of SO2.Direct catalytic decomposition of NO is considered to be the most promising method for denitrification because needn't addition reductant and decomposition products is non-poisonous and harmless N2 and O2.However,direct catalytic decomposition need high reaction temperature and exist serious oxygen hindrance phenomenon.Many researchers are devoted to development of low temperature and high efficiency,environment-friendly denitrification technology.AC has the advantage of cheap and rich source without the problem of production,transportation and store.In addition,AC as good catalyst support and reductant has many characteristics,such as relativity larger specific surface area and microporous structure.Hence,this paper selection solid AC as reducing agents replace NH3 SCR removal of NOx.However,SCR of NO using AC-SCR need high reaction temperatures in the CRM,AC is seriously consume and the effect of denitrification is not ideal.Microwave can accelerate chemical reaction and selective activated polar reactant molecules.Therefore,this paper was develop the microwave catalytic SCR denitrification method using solid AC as reductant and prepared MeOx-CeO2/AC(Me=Fe,Mn,Ni),Ni/AC and MeSx/AC(Me=Ni,Co)microwave catalysts,and investigated the performance of AC-SCR with microwave irradiation.In the MCRM,NO conversion almost reached 100%over Ni/AC and NiSx/AC catalysts at 250 ?,NiOx-CeO2/AC catalyst at 300 ?,MeOx-CeO2/AC(Me=Fe,Mn)and CoSx/AC catalyst at 350 ?.The NiOx-CeO2/AC?Ni/AC and NiSx/AC catalysts catalytic activity almost are not influenced by the O2 concentration and water vapour in exhaust gas in the MCRM.In the presence of SO2,the activated component metal Ni of Ni/AC catalyst and NiSx of NiSx/AC catalyst reacts with SO2 formation NiO lead to catalysts lost activity in the durability test of AC reductants SCR of NO in the MCRM.Microwave can effectively improve the denitrification performance of SCR at low temperature.Therefore,this paper is reported directly decomposition of NO over LaSrBO4(B=Cu,Ni,Co)catalysts with microwave irradiation.The highest NO conversion is 94.6%over LaSrCuO4 at 350 ?,91%over LaSrCoO4 at 250 ?,91.2%over LaSrNiO4 at 300 ? in the MCRM.The LaSrCuO4 catalyst catalytic activity of decomposition NO almost is not influenced bythe O2 in exhaust gas in the MCRM.This paper is revealed microwave catalytic effect and microwave selective effect through the research of removal of NO with microwave irradiation.Microwave irradiation exhibits microwave catalytic effect,the reaction temperature could be efficiently decreased and the catalysts catalytic could be efficiently improved with microwave irradiation.However,microwave irradiation exhibits microwave selective effect,the main reaction products is polar molecules and almost haven't non-polar molecules by-products with microwave irradiation.Furthermore,the catalytic process almost is not influenced by the non-polar molecules in exhaust gas with microwave irradiation.