NO is the main component of nitrogen oxides in the flue gas, accounting for about 95%. The dissolution rate of NO in water is very low,But NO2 and N2O5 are easy to dissolve in the water to produce HNO2 and HNO3, which can be absorbed with SO2, so that can achieve simultaneous desulfurization and denigration.
Ozone as a kind of clean and strong oxidizing agent can quickly and effectively oxidize NO2 into NO, N2O3 and N2O5. While the electron beam method and pulse corona method can produce strong oxidizing agent, such as·OH,·HO2 and so on, the working environment is harsh, the free radical survival time is very short and energy consumption is high. But the O3 life cycle is relatively long. By ionizing a small amount of oxygen or air to produce ozone, the ozone is mixed with flue gas, and then using the alkali absorption, NOx is converted to nitrate and N2. NOx removal rate reached 95% and desulfurization rate reached 100%, reducing energy consumption significantly.
Compared with the traditional SCR and SNCR method, the ozone desulfurization and denitrification method does not produce NH3 leakage; thus, there are no security risk and pollution problems.
Tianjin iron and steel plant engineering case
The project put ozone and other strong oxidizing agent into the desulfurization tower, the NO in the flue gas is oxidized into NOx, then in the desulfurizing tower with alkaline water spraying boiler flue gas, removal from flue gas SO2, NOx and CO2. At the same time, the process has high removal performance of mercury, can reach more than 95% of the desulfurization rate and more than 85% of the denitrification and decarburization rate.