Preparation Of Activated Carbon Supported Copper-manganese Based Catalyst And Its Synergistic Control Of NO_x And CO In Coke Oven Flue Gas

In China’s energy structure,coal occupies an important position,but the control of coke oven flue gas is still in the preliminary exploration stage,so the development of coke oven flue gas control technology is very important,so it is imperative to carry out coke oven flue gas emission control technologies.In this paper,copper and manganese oxide were loaded on the surface of activated carbon（AC）to prepare composite catalysts.The NO_xas well as CO conversion was investigated;besides,the preparation methods and preparation conditions were optimized.The main purpose of this study is to develop a catalyst with high efficiency and low temperature catalytic activity for NO_xand CO removal.Firstly,the activated carbon was modified with nitric acid,and it was found that the pore size of the activated carbon after pretreatment with 10%HNO₃was the largest,up to 5.21 nm,which was more conducive to the loading of metal oxides.A series of Mn O₂/AC catalysts were prepared by impregnating the modified granular activated carbon in manganese nitrate solution.The effects of nitric acid pretreatment concentration,immersion concentration and roasting temperature on NOx removal were studied systematically.After optimization,the best nitric acid pretreatment concentration,impregnation concentration and calcination temperature was 10%,0.4 M and 400 ^oC.Under this conditions,the conversion rate of NO_xwas 78.7%（Reaction temperature 180 ^oC）.On the basis of manganese,the active component copper was further introduced,the Cu_yMn_zO_x/AC catalyst was successfully prepared and characterized.The effect of different copper-manganese ratios on NO_xremoval performance was optimized.When the ratio was 1:2,the catalyst presented the best NO_xconversion of 77.6%.In order to further improve the activity of the catalyst and the simultaneous removal of NO_xand CO,co-precipitation method was used to successfully load layered double hydroxide（LDH）on activated carbon powder,and then Cu_xMn_yAl₁-NO₃LDH/AC derived catalyst was prepared by calcination at 400 ^oC for 5 h.The effects of the ratio of copper to manganese in LDH and different ratios of LDH to AC（10:1,5:1,2:1,1:2,1:10）on NO_x,CO conversion and N₂selectivity were investigated.The results showed that when the ratio of copper to manganese in LDH was 1:2,the ratio of LDH to AC was 2:1,and the reaction temperature was 140 ^oC,the conversion rates of NO_xand CO are the highest,which can reach 91%and 98%,respectively.At the same time,it exhibited good N₂selectivity.In addition,the reaction activation energy is calculated from the perspective of reaction kinetics,it is found that the catalyst with the best catalytic activity has a lower activation energy,and the lower activation energy is easier to carry out the catalytic reaction.