Nox emission reduction system based on ignition and sintering of dry mixture

Abstract

The invention discloses a NOx emission reduction system based on ignition and sintering of a dry mixture. According to the technical scheme, the system comprises a sintering machine; bellows are arranged below trolleys of the sintering machine; the sintering is sequentially divided into four areas including a preheating and drying section, an ignition section, a flue gas quick-heating section and a tail section in the advancing direction of the trolleys; the bellows below the tail section are connected through fluidized bed reactors, a high-temperature flue gas main flue, a high-temperature flue gas dust remover, a high-temperature flue gas circulating fan and a high-temperature flue gas circulating pipe sequentially with a high-temperature circulating flue gas cover located above the preheating and drying section. With the system, the pollution emission amount is small, the recovery rate of waste heat of sintering flue gas is high, no outsourced denitration catalyst is used, and generation of NOx in the flue gas is effectively reduced.

Description

technical field [0001] The invention relates to the field of environmental protection, in particular to a NOx emission reduction system based on ignition and sintering of dry mixture. Background technique [0002] With the rapid development of the iron and steel industry, the output and quality of natural rich ore are far from meeting the requirements of blast furnace smelting. In order to meet the increasingly large-scale blast furnace production, the sintering technology of artificial lump ore has been greatly developed. Its material handling capacity accounts for about the second place in the iron and steel complex and has become an important production process in the modern iron and steel industry. However, due to the high energy consumption and large amount of pollutants generated in this process, the sustainable development of the iron and steel industry has been seriously restricted. The energy consumption of this process accounts for 10-20% of the total energy consu...

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Problems solved by technology

[0005] From the above technical and engineering cases, it can be seen that the treatment process of sintering flue gas pollutants is mostly concentrated on the combination of single technical units for single pollutant treatment. A series of problems such as complex control, large investment, and high operating costs have brought huge cost pressures to steel companies

Especially when the SCR denitrification technology, which is generally accepted at present, is applied in the treatment of sintering flue gas, because sulfur will cause catalyst poisoning, the SCR denitrification system is generally installed after the desulfurization system, resulting in a further decrease in flue gas temperature, which is much lower than the SCR denitrification temperature window

Therefore, in the current sintering flue gas SCR denitrification project case, additional energy needs to be provided to raise the temperature of the flue gas to reach the SCR denitrification temperature window, and the additional cost of denitrification

At the same time, the SCR denitrification catalyst contains precious metals, the manufacturing cost is high, and it is difficult to dispose after failure

[0006] In response to these problems, through the source of the sintering process and the whole process of process production, the development of sintering flue gas multi-pollutant whole-process control coupling technology has become a research hotspot in the reduction of pollution in the steel sintering process, such as Ninggang, Shagang and other domestic enterprises The engineering application of flue gas circulation technology to reduce the total amount of pollutant emissions has been carried out. Although the sintering flue gas circulation has certain energy-saving and emission reduction effects, the effect of reducing NOx emissions in the sintering flue gas is far from meeting the national environmental protection requirements. standard requirement

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