Method for removing nitrogen oxide in sintering flue gas

Abstract

The invention discloses a method for desulfurizing nitric oxides in the sintering flue gas, comprising adding ammoniation to the sinter mixture and then sintering. The said ammoniation is distilled waste water or cyanogen and amino group salt of chemical plant such as carbamide, ammonium salt, ammonia and coal plant. The level of addition of said ammoniation is X=n*[(XNOx+XSO#-[2]*2) / m]. The method for desulfurizing nitric oxides in the sintering flue gas in the invention adds low-cost ammoniation to the sinter mixture, transmutes the NOx exhaust in sintering process to be N2 without harm to the environment, and also desulfurizes the SO2 producted in the sintering process at the same time. The method can desulfurize NOx at a lower cost, the desulfurizing ratio of saltpetre can reach to 66.7 percent, and the desulfurizing ratio of SO2 can reach to 80-95 percent.

Description

technical field The invention relates to a method for removing nitrogen oxides, in particular to a method for removing nitrogen oxides in sintering flue gas. Background technique NOx is one of the main air pollutants, which is very harmful to the human body. These pollution factors reduce the growth rate of forests and crops, cause corrosion to metals and calcium carbonate-containing building materials, and form acid rain to produce serious air pollution. event. The NOx emission of the sintering plant accounts for more than 50% of the total emission of the long-process iron and steel plant, but none of the hundreds of sintering machines in my country has treated the NOx in the flue gas. At present, flue gas denitrification technologies include gas phase reaction method, liquid phase reaction method, adsorption method, liquid membrane method and microbial method. The gas phase reaction method is further divided into: (i) electron beam irradiation method and pulsed corona ...

AI Technical Summary

Problems solved by technology

The liquid phase absorption method is a method of removing NOx by oxidation, reduction or complexing agent, because the solubility of NOx is low, so the absorption rate is low, and it is difficult to deal with nitrate in the liquid phase

At present, the exhaust gas denitrification technology actually adopted by foreign sintering plants is selective catalytic reduction method, the denitrification effect is very good, the denitrification rate can reach about 80%, but the disadvantage is that the investment is too high, and the investment of a set of exhaust gas denitrification system is equivalent to a sintering plant. 60% to 70% of the machine investment, coupled with higher catalyst, liquid ammonia usage fees and operation and maintenance fees, will increase the cost of pig iron