A system and method for desulfurization and denitrification of sintering flue gas

Abstract

A desulfurization and denitrification system and method for sintering flue gas, including a mixing and granulating device, a main smoke exhaust pipeline, an electrostatic precipitator, a ring cooler, a bypass valve, an activated carbon absorption tower, a bag filter, and an activated carbon storage bin and chimneys. Add an induced draft fan, heat recovery cover and hot air pipe above the ring cooler, and add a urea solution tank on the mixing and granulating device. Mix the urea solution into the sintering mixture at a ratio of 0.5 to 3%, and the NH produced by thermal decomposition of urea 3 and SO in the sintering flue gas 2 The reaction produces ammonium sulfate, and the excess NH 3 with SO 2 On the contrary, it is discharged along the main exhaust pipe; the induced draft fan transfers the recovered waste heat of the annular cooler into the pipeline between the electrostatic precipitator and the activated carbon absorption tower through the hot air pipe, and heats the sintering flue gas to above 150°C to accelerate the NH 3 Reaction efficiency with NOx in sintering flue gas. The invention can greatly improve the destocking efficiency, realize simultaneous desulfurization and denitrification of sintering flue gas, and make the concentration of nitrogen oxides in the outlet flue gas less than 300mg / m 3 .

Description

technical field [0001] The invention belongs to the field of flue gas treatment in iron and steel enterprises, and in particular relates to a system and method suitable for desulfurization and denitrification of sintering flue gas. Background technique [0002] In the "Twelfth Five-Year Plan", my country clarified the indicators for comprehensive control of nitrogen oxides (NOx), and the emission concentration of nitrogen oxides in sintering flue gas is required to be no more than 300mg / m 3 , SO in the sintering flue gas 2 And NOx emissions need to be treated in order to meet the emission standards. [0003] According to the characteristics of sintering flue gas, the concentration of nitrogen oxides is relatively low. Selective non-catalytic reduction denitrification process (SNCR) requires a high temperature above 950 °C, and it is unrealistic to reheat the sintering flue gas. Selective catalytic reduction denitrification process (SCR) also requires high temperature abov...

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Problems solved by technology

[0009] In summary, due to the low concentration of nitrogen oxides in sintering flue gas, although the existing desulfurization and denitrification devices and methods have their own strengths, none of them can fully adapt to the desulfurization and denitrification of sintering flue gas.

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