Study On Simultaneous Desulfurization And Denitration By Urea/Chlorine Dioxide Compound Absorbent

In recent years,industrial coal-fired boilers in our country have these characteristics such as large volume,high consumption of coal,high pollution intensity and imperfect desulfurization and denitration facilities.In industrial coal-fired boilers,it is very common to see that desulfurization and denitration facilities are not in running station and flue gas discharged arbitrarily.The main reason of the situation is that the existing desulfurization and denitration methods cannot fully meet the industrial boiler's flue gas pollution control requirements.Besides,those methods also got the problems of high investments,high operating cost and inconvenient to operate,so they are difficult to accept for the enterprises.To develop a method that is easier to operate,have lower operating cost and can remove SO2 and NOx at the same time is very necessary for industrial boilers,especially for small and medium scale boilers.Based on the desulfurization and denitration method of urea solution,via adding some chlorine dioxide into urea solution,this paper looked forward to having the result of higher efficiencies of desulfurization and denitration.First,conduct several experiments to ascertain fortified concentration of chlorine dioxide and obtain the impact of pH,temperature and time on the concentration of effective chlorine.Then,in different experimental conditions,do several simultaneous desulfurization and denitrification experiments in the self-designed spray tower device.According to the comprehensive consideration of experimental results,the optimal operating parameters are confirmed:when initial concentration of NOx is 600mg/m3 and initial concentration of SO2 is 900mg/m3,the concentration of chlorine dioxide is 200mg/L,n(ClO2):n((NH2)2CO)=1:4,gas flow is 30m3/h,the L/G is 19L/m3 and the reaction temperature is 40 ?.Under the optimal test condition,the efficiencies of desulfurization and denitration could retain 100%and 93.9%respectively.Moreover,this paper based on the experimental data of ion chromatography and five step iodometry method,assumed that the possible reaction mechanism of urea/chlorine dioxide compound absorption liquid reasonably.Through to calculate ?G??K???H? of reaction and analysis SO2,NOx partial pressure under different temperature,proved that this method can remove SO2 and NOx at the same time,and the reaction between compound absorption and SO2,NOx is deeply spontaneous.In addition,this paper also affirmed the industrial extension property of the compound absorption based on the analysis of economic benefit.The new method of simultaneous desulfurization and denitrification by urea/chlorine dioxide compound absorption this paper suggested,has high efficiencies of desulfurization and denitration,yet with advantages of low-cost absorbent,plain equipment,simple process,and easy to operate.It is sure of that this new method will have a very good industrial application prospect.