Experimental Study On Oxidation Of Denitration By Chlorine Dioxide And Reaction Kinetics

At present, the nitrogen pollution presents a growing trend. Coal combustion is a major source of nitrogen oxides and large coal-fired industrial boiler NO_x emissions of nearly 2 million tons. To develop a kind of economic efficiency, suitable for middle and small coal-fired boiler flue gas denitration technology in China is necessary. This articl everified the feasibility of wet denitration process through reaction kinetics of the sulfurous acid ions with NO₂ and studied both the oxidation of NO and NO₂ absorption process by the building of membrane reactor system.This paper carried out the sulfite absorption NO₂ reaction kinetics study by adopting double the stirred tank reactor system. Study found that 30℃, the reaction of NO₂ was first order reaction for concentration of NO₂ interface, responsed to Na₂SO₃ as well. The absorption rate of NO₂ over the entrance of NO₂ partial pressure increases and the approximate linear proportional relationship. NO generation increased with the NO₂ inlet concentration. Amount of NO in NaHSO₃ solution produced greater than the NO₂ in Na₂SO₃ solution absorption quantity.And then, studied the influence of various parameters on the chlorine dioxide oxidation of NO rules, main parameters including reaction temperature, concentration and residence time of the entry NO. The results showed that chlorine dioxide oxidation NO efficiency decreased with the reaction temperature, but the overall reduction was small.Reaction temperature from70℃ to 98℃, NO oxidation efficiency wasfrom 82% to 73%.The ability of ClO₂ oxidation reduced gradually bymolar ratio of ClO₂ and NO dropping from 1.2 to 1.2. With the increase of residence time, oxidation rate increased and under the condition of excessive ClO₂, oxidation efficiency was at high level, reflecting the reaction rate fast.Finally, the article studied operation parameters and operation parameters influence on absorption denitration efficiencywith the aid of liquid falling film reactors. Liquid phase on the impact of operating parameters on the denitration process research has shown that Na₂SO₃ effect is best in different absorption liquid. The absorptive capacity of NO₂ along the range from 0.25 to 1.0m in the tower, MgSO₃> CaSO₃, along the 1.0 2.0 m, CaSO₃> MgSO₃. As the liquid gas ratiofrom 19.8 L/m3 to 2.7 L/m3, NO₂ absorption rate increased, according to the flow characteristics divided into the laminar flow area and intending to laminar flow area. With the increase of absorbing liquid concentration, denitration rate are on the rise. Gas phase on the impact of operating parameters on the denitration process research has shown that under the condition of experiment with improving the tower gas velocity, due to the increase in gas liquid mass transfer coefficient, mass transfer issignificantly enhanced.With NO₂ concentration increased, the denitration rised firstly then a fall. O₂ content exceeds 4%, the effects of O₂ on NO₂ is limited.