Synergic removal method for multiphase contaminant in sintering flue gas

Abstract

The invention relates to a synergic removal method for a multiphase contaminant in sintering flue gas. The method comprises the following steps: performing primary dust removal on the sintering flue gas, pressurizing the dust removed sintering flue gas, and partially oxidizing the gas; performing catalytic oxidation on the oxidized flue gas to generate nitric acid and sulfuric acid, neutralizing nitric acid and sulfuric acid with ammonia water to generate ammonium sulfate and ammonium nitrate, and conveying a mixed solution of ammonium sulfate and ammonium nitrate to an ammonium sulfate evaporative crystallization system; demisting the flue gas subjected to catalytic oxidation, performing chemical agglomeration and secondary dust removal and purification on the gas, and discharging the purified flue gas. The method not only can treat the multiphase contaminant in the sintering flue gas, but also can obtain the high-quality byproducts.

Description

technical field [0001] The invention relates to the field of environmental protection, in particular to a method for synergistic removal of multiphase pollutants from sintering flue gas. Background technique [0002] Sintering flue gas contains a variety of pollutants, such as sulfur dioxide and nitrogen oxides in the gas phase, dust and heavy metals, dioxins and other substances adhering to the dust in the solid phase, and some soluble inorganic salts will be carried by the moisture in the flue gas. Sintering flue gas also has the characteristics that the amount of flue gas and flue gas characteristics vary drastically with the type of ore and production load. The existing flue gas treatment system mainly deals with single pollutants. For such complex flue gas characteristics, the flue gas treatment system is also very complicated, and it is difficult to respond to load changes in time. [0003] For the removal of sulfur dioxide, limestone-gypsum method or ammonia-ammonium...

AI Technical Summary

Problems solved by technology

The existing flue gas treatment system mainly deals with single pollutants. For such complex flue gas characteristics, the flue gas treatment system is also very complicated, and it is difficult to respond to load changes in time.

[0003] For the removal of sulfur dioxide, limestone-gypsum method or ammonia-ammonium sulfate method are commonly used in engineering, but neither of these two systems can handle nitrogen oxides, and the treated solution contains dust and other impurities, which have an impact on the quality of by-products

The FeII (EDCA) method or other catalytic removal systems for the simultaneous removal of sulfur dioxide and nitrogen oxides also have the problem that the treated solution contains dust and other impurities, which affect the quality of by-products

Moreover, the above-mentioned systems all have the problem of carrying a large amount of water and by-products in the flue gas, which not only reduces the output of by-products, but also increases the consumption of process water, and more importantly, it is easy to cause secondary pollution

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