Studies On Removal Of Nitric Oxide By Iron And Ferrous Compounds Combined With Downstream Calcium Hydroxide Absorption

Nitrogen oxide is one of major air pollutants causing serious harm to environment,ecological and human health.A 10%reduction in total amount of NO_x emissions was determined in the“twelfth five-year plan”in China.These studies of nitrogen oxide abatement technologies have great academic value and practical significance.The removal rate of NO by iron and ferrous compounds were experimentally investigated in a tubular reactor,including two parts.The influence of opaeration parameters such as temperature,impot concentration and gas flow on the reduction of NO by iron in N₂ and the influence of oxygen were investigated in the first part.The removal of NO by FeCl₂ combined with downstream Ca?OH?₂ absorption was experimentally in the second part.Experimental results showed that the removal of NO in nitrogen gas increased with the increase of reaction temperature in N₂.The removal of NO decreased with the increase of NO import concentration.The increase of gas flow also led to the decrease of NO reduction.But with the presence of oxygen in the sample gas,the removal of NO was largely inhibited,and the greater the oxygen concentration was,the stronger the inhibition was.Besides,it was found that FeS?FeSO₄ and FeCl₂ were effective to remove NO in N₂,the highest removal ratio of NO was reaction with FeS and the lowest was FeSO₄.Meanwhile,the oxygen also had a negative effect on NO removal by FeS and FeSO₄.Experimental results also showed that FeCl₂ combined with Ca?OH?₂absorption was good for the NO removal.The removal of NO was above90%with the presence of 5%O₂ in sample gas steam at the temperature above 400?.XRD analysis showed that was finally oxidized to Fe₂O₃ and FeCl₃.And,NO was oxidized to NO₂ by reaction with the produced FeCl₃FeCl₂ from decomposition,which was removed by the downstream absorption of Ca?OH?₂.