Pellet roasting flue gas denitration and desulfurization device and method based on chain grate-rotary kiln

Abstract

The invention provides a pellet roasting flue gas denitration and desulfurization device and a method based on a chain grate-rotary kiln. The pellet roasting flue gas denitration and desulfurization device comprises a reaction system and a flue gas treatment system; the reaction system comprises a chain grate and a rotary kiln which are connected in sequence; the flue gas treatment system comprises an SNCR unit, an SCR unit, an ozone oxidation unit and a sulfur-nitrate absorption unit; a flue gas outlet of the rotary kiln is connected to a gas inlet of the chain grate after passing through theSNCR unit, and a gas outlet of the chain grate is sequentially connected with the SCR unit, the ozone oxidation unit and the sulfur-nitrate absorption unit. According to the device disclosed by the invention, a pellet production system and the flue gas treatment system are combined, and denitration and desulfurization treatment is sequentially carried out by utilizing the temperature and composition characteristics of roasting flue gas and heat exchange with the chain grate, so that the removal efficiency of flue gas pollutants is improved; the device is capable of increasing heat energy utilization efficiency, reducing energy consumption and operation cost through heat exchange with flue gas at different stages based on the temperature characteristics of different areas of the chain grate.

Description

technical field [0001] The invention belongs to the technical field of flue gas treatment, and relates to a pellet roasting flue gas denitrification and desulfurization device and method, in particular to a pellet roasting flue gas denitrification and desulfurization device and method based on a grate-rotary kiln. Background technique [0002] At present, in order to improve the technical and economic indicators of ironmaking, the main production enterprises in the iron and steel industry have adjusted the structure of the blast furnace, expanded the demand for pellets, and made the pellets develop better. Compared with sinter, pellets have uniform particle size, high iron content, good reducibility, and good low-temperature strength. The use of pellets can generally increase production and reduce coke ratio. [0003] The pellet production process mainly includes raw material preparation, batching, mixing, pelletizing, drying, roasting, cooling, and finished product screenin...

AI Technical Summary

Problems solved by technology

The flue gas processed by this system is mainly the flue gas in the second preheating section of the grate machine. The temperature of this part of the flue gas is relatively high, so it is difficult to directly perform SCR denitrification treatment, and the flue gas in the rotary kiln is not treated. Incomplete treatment

[0006] CN 206168206U discloses a grate-rotary kiln denitrification system, including a first preheating section and a second preheating section for heating pellets, and also includes a denitrification device for removing nitrogen oxides in flue gas, The denitrification device is installed in the inner cavity of the second preheating section; this device only uses the temperature of the second preheating section to perform SNCR treatment on the flue gas, but the processing time and efficiency of this stage are low, and it is difficult to meet the emission requirements. And only denitrification treatment is carried out, and sulfur oxides are not treated, so they cannot be discharged directly

Images