Research On Integrated Technology Of Flue Gas Desulfurization And Denitrification

Air pollution is one of the environmental problems that threaten the sustainable development of human beings. Among them, the sulfur dioxide and nitrogen oxides produced by fossil fuel combustion are the most common sources of pollution in the atmosphere, and the control of excessive emissions of fuel flue gas is the main means of environmental pollution in china. With the release and implementation of the new environmental standards, the demand for industrial flue gas desulfurization and denitration is getting higher and higher.In this paper, ozone (O3) as oxidant, urea, ammonium sulfite solution desulfurization and denitrification of the integration of the experimental conditions and absorption mechanism study:First of all, from the four aspects of gas-liquid mass transfer process, Gibbs function, thermodynamics and dynamics. It is proved that the application of urea and ammonium sulfite in the process of desulfurization and denitrification is feasible, and the reaction rate is high, the product is simple, no two pollution.Secondly, the pilot scale packed tower was designed by ourselves, and the calculation of the fluid mechanics was carried out for the two-stage cascade packed tower of the pilot scale. By the calculation of packed column gas velocity of flooding is 0.117 m·s-1, the empty tower gas proper speed is 1.36×10-3-9.36×10-2m·s-1,the minimum flow rate is 15.04 m3·(m2·h)-1, we can get the smallest fluid absorption from the normal gas ratio is 43.83 L·m-3.Thirdly, the mechanism of urea desulfurization and denitrification was analyzed, and the factors such as liquid flow rate, residence time, ozone consumption and pH were investigated. The experimental results show that the denitrification rate increases with the increase of ozone consumption and residence time. When the amount of liquid increased, the denitrification firstly increased and then became stable. With the increase of the pH value, the desulfurization firstly increased and then became stable, and the denitrification firstly increased and then decreased. When the pH was 7, the denitrification rate was the best. SO2 and NOx simultaneous removal of NOx removal efficiency of 5%-15% higher than separate denitrification, indicating that the existence of SO2 main material synergistic effects and increase the denitrification rate of denitrification for ammonium sulfite, adding suitable additives and helps to improve the denitrification efficiency. The desulfurization rate of urea was higher than that of ammonium sulfite, and the denitrification rate was lower than that of ammonium sulfite.Finally, in the design of the flue gas desulfurization denitrification integration process, when the liquid flow rate of 0.8 m3·h-1 and the residence time of 30 s, the urea solution concentration of 20%, the ammonium sulfite concentration of 0.1 mol·L-1, the concentration of A is 5 g·L-1,absorption temperature of 50 °C,n (O3): n (NO) =1:1, pH is 7, the removal rate of SO2 is 96.21%, NOx removal rate can reach 87.02%.