Study On Simultaneous Desulfurization And Denitration By Improved Double Alkali Method

In our country, the contamination caused by dioxide and nitrogen in coal-fired flue gas is very serious. The total emissions have been ranked first in the world and caused hundred billions economic losses every year. Because of quantity, wide range and imperfect desulfurization and denitration facilities, small and medium scale boilers pollution becoming the main source of air pollution. The existing desulfurization and denitration methods can not adapt to the requirements of small and medium scale boilers pollution neither in technology nor economy. Thus, it’s necessary to develop a method to remove SO2 and NOX for small and medium scale boilers.Based on the desulfurization method of double alkali method, by adding some chlorine dioxide into absorbent this paper looked forward to having the result of higher efficiencies of desulfurization and denitration. simultaneous desulfurization and denitrification experiments are conducted in the self-designed spray tower device. The effects of initial S02 and NO concentration, component of absorbent, reaction temperature and liquid/gas ratio on the removal efficiency of the pollutants were investigated. The results showed that the best absorbent are when NaOH concentration was 100mg/L and the ClO2 concentration (take effective chlorine as representation) was 152.44mg/L.when the flow rate of flue gas was 30 m3/h the absorbent volume was 10L and reaction temperature was 50 ℃, SO2 and NOx removal efficiency on simulated flue whose initial SO2 and NO concentration was 1300 mg/m3 and 600 mg/m3 could reached to 100% and 75.4% respectively.Moreover, this paper based on the experimental data of ion chromatography and five step iodometry method, assumed that the possible reaction mechanism reasonably.The improved double alkali method can both desulfurization and denitrification without adding equipment nor changing technology. In addition, this paper also affirmed the industrial extension property of the compound absorption based on the analysis of economic benefit.