Study Of Denitration By Wet Oxidation In A Rotating Packed Bed

The abatement of nitric oxides (NOx)is becoming one of the important challenges since NOx is the source of serious eco-environmental problems and people’s healthy problems. In another hand, the emission standards are increasing more stringenter than before. The status quo of denitration in China is very distinctive. The denitration method is adopted by the fully reinforced enterprise, while the wet denitration method is still used by the SMEs(small and medium-sized enterprises) who make a great percentage of this country. With the introduction of the latest emission standards, lots of denitration equipments’processing power cannot meet the requirement of national standards. New denitration technology and Secondary denitration equipment was necessary in this country. Considering social and economical factors, studies on the treatment of nitrogen oxides by wet process at normal pressure appear to be an increasingly important theoretical and practical significance for the prevention of environmental pollutants.A rotating packed bed (RPB, also called Higee device) is a novel equipment for the intensification of mass transfer and multiphase mixing. It is dozens to hundreds of times the mass transfer ability and multiphase mixing ability of RPB than other equipment. RPB has many advantages such as: simplify operation, high mobility, good stability, large processing capacity, small floor coverage and less investment. Because of those characters of RPB, it has been widely used in chemical processes. Such as absorption, gas treatment and so on. So a Research of wet denitration in RPB is valuable both in theory and in practice.Simulated flue gas containing NOx(instead of NO) was pre-oxidized by O3and absorbed by NaOH or H2O2solution in a rotating packed bed (RPB) in this study. The effects of different operation conditions and additives on denitration efficiency are investigated. On the basis of the experimental studies, the expression of the volumetric is given overall mass transfer coefficients. We also investigat the impacts of O3/NOx molar ratio, absorption solution, gas-liquid ratio, initial pH value of the absorption solution, initial concentration of NOX and the cycling time etc. on KGa.The best operation condition in the NaOH absorption system is determined as O3/NOx molar ratio of0.6, absorbent concentration of0.05mol/L, rotation speed of800r/min, and gas-liquid ratio of14:1. But for the H2O2absorption system, the best operation condition is as O3/NOx molar ratio of0.8, absorbent concentration of0.025mol/L, rotation speed of800r/min and gas-liquid ratio of14:1. The initial pH value of the H2O2absorption solution, the initial concentration of NOx and the cycling time also have an effect on denitration efficiencyIt is found that denitration efficiency is increased with O3/NOx molar ratio, absorbent concentration and liquid/gas ratio and decreased with initial pH value of the H2O2absorption solution, the initial concentration of NOx and the cycling time. And it is increased first and then decreased with an increasing rotation speed. The addition of KMnO4or H2O2in NaOH absorbent has a positive effect on the denitration effects. We need to undertake choosing according to the actual. The influence rule on KGa of the operation condition is equal to the influence rule on denitration efficiency. The results are tallying with the experimental results.