Preparation method of pellets for reducing emission of SO2 and NOx in sintering process

Abstract

The invention discloses a preparation method of pellets for reducing emission of SO2 and NOx in a sintering process, and belongs to the technical field of pollutant emission reduction in the sintering process. The preparation method comprises the following steps that firstly, inner-layer pellets are prepared from an inner-layer pelletizing material, an ammonia inhibitor is added in the preparation process of the inner-layer pellets, the ammonia inhibitor is decomposed by heating to release ammonia gas, the content of N element in the ammonia inhibitor is enabled to account for 0.02%-0.15% of the mass of the inner-layer pellets, and then the outer parts of the inner-layer pellets are coated with coating layers by means of an outer-layer pelletizing material; the wrapping layer outside the pellets can play a role in delaying the release rate of NH3, so that the NH3 is released stably in a centralized manner at the temperature of 600-800 DEG C, and NOx is discharged at the temperature of 650 DEG C and is consistent with the release temperature interval of the NH3, so that the NOx reacts with the NH3; and meanwhile, generation of dioxin can be inhibited in the cooling process until the temperature of the sintering flue gas is reduced to be lower than the dioxin synthesis temperature, and the emission reduction efficiency of SO2 and dioxin is improved.

Description

technical field [0001] The invention relates to the technical field of pollutant emission reduction in the sintering process, and more specifically, relates to a method for preparing pellets used for reducing SO2 and NOx emissions in the sintering process. Background technique [0002] With the increasingly serious environmental problems and the gradual enhancement of people's awareness of environmental protection, the iron and steel industry, as a major source of pollutant emissions, has received more and more attention from the national environmental protection department. In 2019, my country's Ministry of Ecology and Environment and other five ministries and commissions jointly issued the "Opinions on Promoting the Implementation of Ultra-Low Emissions in the Iron and Steel Industry", requiring iron and steel enterprises across the country to significantly reduce pollutant emission levels, and set the emission standards for sintering / pelletizing process pollutants as parti...

AI Technical Summary

Problems solved by technology

[0006] The present invention aims at adding ammonia inhibitors in the sintering material in the prior art, which will lead to SO in the sintering process 2 , NO X and dioxin and other pollutants, such as poor online emission reduction effect and high cost of flue gas treatment; provide a method for preparing pellets for reducing SO2 and NOx emissions in the sintering process, by preparing a double layer of pellets in the inner layer and the coating layer The layer structure wraps the ammonia inhibitor, adding it to the sintering material can effectively slow down the NH produced by the pellets at high sintering temperature 3 Release speed, so that it can fully react with the pollutants generated by sintering, so as to achieve the purpose of synergistic emission reduction

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