Experimental Study On Sulphur Dioxide And Nitric Oxide Control Technology By Oxidation In Gas Phase And Absorption In Liquid Phase

Although the traditional coal-fired flue gas desulfurization and denitrification technology has been widely used in industry,there still exist some problems such as non-ideal removal effect,only one kind of pollutant removed,and high land occupancy.With the continuous improved requirement of air pollutant discharge standards in our country,the development of efficient economic desulfurization and denitrification integration techniques,has become an important emerging research areas.In this paper,a set of technological process about chlorine dioxide gas phase oxidation,hydrogen peroxide/sodium hydroxide liquid phase absorption is developed.In this paper,the experiments of chlorine dioxide gas phase oxidation process,hydrogen peroxide/sodium hydroxide liquid phase absorption process and two process coupled desulfurization and denitrification were carried out by self-made and highly automated double-tower continuous operation of small test equipment.Main conclusions as follows:1.In the process of chlorine dioxide gas phase oxidation of sulfur dioxide and nitric oxide,the temperature is conducive to oxidation of sulfur dioxide,but not conducive to oxidation of nitric oxide.When the reaction temperature is 80?,the total reaction time is 4s and the molar ratio[ClO2]:[SO2]:[NO]?1.6:0.7:1,the oxidation rate of nitric oxide in simulated flue gas is 95%,the oxidation rate of sulfur dioxide is 85%.2.In the hydrogen peroxide/sodium hydroxide liquid phase absorption of sulfur dioxide and nitric oxide process,the high concentration of HO2-is conducive to the oxidation of pollutants.When in 50 ?,the condition of[HO2-]:[H2O2]=50%is that the OH-concentration must reach 0.0104 mol·L-1 or more and the pH minimum is 11.26.Without considering the effect of carbon dioxide,when the absorption of hydrogen peroxide 0.6mol·L-1,sodium hydroxide 0.1mol·L-1,the simulated flue gas nitric oxide absorption rate of 80%,sulfur dioxide absorption rate of 99%.3.In the gas phase oxidation-liquid phase absorption desulfurization and denitrification process,set the simulated flue gas sulfur dioxide concentration of less than 3.5ppm,nitric oxide concentration of less than 14.6ppm of the highest emission standards as the goal.Based on the uniform experimental design,the concentration of the flue gas in the oxidation tower was 8.7NL-min-1,the concentration of sulfur dioxide was 700ppm and the concentration of nitric oxide was 975ppm.the key conditions for the discharge of the flue gas were as follows:the concentration of chlorine dioxide in the oxidation tower is about 2500ppm,absorption tower liquid flow 40 ml·min-1,hydrogen peroxide concentration of 1.0 mol·L-1,sodium hydroxide concentration of 1.0 mol·L-1.All the research shows that the gas phase oxidation-liquid phase absorption combined desulfurization and denitrification process has the characteristics of high efficiency,green environmental protection,convenient operation,wide range of removal and continuous stability.In addition,on-site preparation of oxidants and absorbent liquid cost low,spend less freight.In the new situation,the technology development potential is great.