Emission reduction and device for NOx generated in sintering process

Abstract

The invention discloses an emission reduction and device for a NOx generated in a sintering process. The method comprises the three main steps of material preparation, mixing and granulation and sintering. According to the NOx emission reduction scheme, a new coke powder bin and a new lime bin are built, coke powder and some lime do not pass through a coke powder bin and a lime bin of a traditional material preparation chamber, directly enter the new coke powder bin and the new lime bin, enter a strong mixing machine to be mixed evenly, and are pelletized in a pelletizing disc to form a mixture, and the mixture is transferred into the certain position in a secondary cylinder mixing machine. By means of the emission reduction and device for the NOx generated in the sintering process, the purpose that NOx generated in the sintering process is reduced is achieved by adjusting the wrapping state of coke powder without greatly changing the current sintering technology.

Description

technical field

[0001] The invention belongs to the field of sintering emission reduction, in particular to a method and equipment for reducing NOx emission in a sintering process. Background technique

[0002] In the iron and steel industry, sintering is a major pollutant emitter, and NOx emitted by sintering accounts for 50% of the total emissions of the iron and steel industry. In recent years, with the country's gradual emphasis on sintering environmental protection, environmental protection standards have gradually tightened, especially for NOx, from <300mg / Nm3 in the national standard in 2012, to <50mg / Nm3 in 2018 for ultra-low emission drafts. This brings great challenges to the sinter plant. Many enterprises have begun to invest in SCR, activated carbon or oxidation to denitrify processes, which are all terminal treatments, and the input costs are relatively high. 90% of the NOx emission in the sintering process is brought by the coke powder, that is, fuel-ty...

Examples

Embodiment 1

[0030] In this embodiment, the mass ratio of coke powder 1 to coke powder 2 is 1:1, the mass ratio of lime 1 to lime 2 is 1:9, the mass ratio of coke powder 2 to lime 2 is 4:1, and the mass ratio of coke powder 1 and lime 2 is 1:1. The total mass of coke powder 2: the total mass of lime 1 and lime 2: the mass of limestone: the mass of dolomite: the mass of mixed ore: the mass of returned ore = 4:5:2:6:60:23. The residence time of the blend prepared in step (1) in the second mixing is 180s, that is, the second mixing granulation time is 240s, and the residence time of the spherical mixture prepared in step (2) in the secondary cylinder mixer for 30s. Finally, it is desintered together with the rest of the materials, and the NOx emission during the sintering process is 180mg / m 3 .

Embodiment 2

[0031] Embodiment 2: In this embodiment, the mass ratio of coke powder 1 to coke powder 2 is 0:1, the mass ratio of lime 1 to lime 2 is 1:9, and the mass ratio of coke powder 2 to lime 2 is 8:1. Total mass of coke powder 1 and coke powder 2: total mass of limestone 1 and limestone 2: mass of limestone: mass of dolomite: mass of mixed ore: mass of returned ore = 4:5:2:6:60:23. The second mixing granulation time is 20s. Finally, it is desintered together with the rest of the materials, and the NOx emission during the sintering process is 160mg / m 3 .

technical field

[0001] The invention belongs to the field of sintering emission reduction, in particular to a method and equipment for reducing NOx emission in a sintering process. Background technique

[0002] In the iron and steel industry, sintering is a major pollutant emitter, and NOx emitted by sintering accounts for 50% of the total emissions of the iron and steel industry. In recent years, with the country's gradual emphasis on sintering environmental protection, environmental protection standards have gradually tightened, especially for NOx, from <300mg / Nm3 in the national standard in 2012, to <50mg / Nm3 in 2018 for ultra-low emission drafts. This brings great challenges to the sinter plant. Many enterprises have begun to invest in SCR, activated carbon or oxidation to denitrify processes, which are all terminal treatments, and the input costs are relatively high. 90% of the NOx emission in the sintering process is brought by the coke powder, that is, fuel-ty...

Examples

Embodiment 1

[0030] In this embodiment, the mass ratio of coke powder 1 to coke powder 2 is 1:1, the mass ratio of lime 1 to lime 2 is 1:9, the mass ratio of coke powder 2 to lime 2 is 4:1, and the mass ratio of coke powder 1 and lime 2 is 1:1. The total mass of coke powder 2: the total mass of lime 1 and lime 2: the mass of limestone: the mass of dolomite: the mass of mixed ore: the mass of returned ore = 4:5:2:6:60:23. The residence time of the blend prepared in step (1) in the second mixing is 180s, that is, the second mixing granulation time is 240s, and the residence time of the spherical mixture prepared in step (2) in the secondary cylinder mixer for 30s. Finally, it is desintered together with the rest of the materials, and the NOx emission during the sintering process is 180mg / m 3 .

Embodiment 2

[0031] Embodiment 2: In this embodiment, the mass ratio of coke powder 1 to coke powder 2 is 0:1, the mass ratio of lime 1 to lime 2 is 1:9, and the mass ratio of coke powder 2 to lime 2 is 8:1. Total mass of coke powder 1 and coke powder 2: total mass of limestone 1 and limestone 2: mass of limestone: mass of dolomite: mass of mixed ore: mass of returned ore = 4:5:2:6:60:23. The second mixing granulation time is 20s. Finally, it is desintered together with the rest of the materials, and the NOx emission during the sintering process is 160mg / m 3 .

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