Sectional circulating soot catalytic denitration process for sintering flue gas

Abstract

The invention relates to a sectional circulating soot catalytic denitration process for a sintering flue gas. According to the technical scheme, the process comprises the steps as follows: the sintering flue gas passes through a sintered material layer, a backing material, a bottom grate of a trolley of a sintering machine and an air bellow and enters a flue gas pipeline; the sintering machine is sequentially divided into an ignition segment, a machine head segment, a flue gas rapid heating segment and a machine tail segment along the advancing direction of the trolley; the flue gas pipeline comprises a main flue and a circulating flue gas main flue; the sintering flue gas collected by the machine tail segment, the flue gas rapid heating segment and the air bellow at the lower part of the ignition segment enters the main flue; and the sintering flue gas collected by the air bellow at the lower part of the machine head segment of the sintering machine enters the circulating flue gas main flue, is fed into a circulating flue gas hood at the upper part of the trolley at the machine tail segment and the flue gas rapid heating segment of the sintering machine after dust is removed through a circulating flue gas dust collector and then enters a sintered material layer again. The sectional circulating soot catalytic denitration process is simple in technological process; sintering soot autocatalytic denitration is achieved without outsourcing a denitration catalyst; and the sectional circulating soot catalytic denitration process is good in denitration effect, high in waste heat recovery rate, small in floor area, friendly to environment, low in denitration equipment investment and low in denitration operation cost.

Description

technical field [0001] The invention relates to a flue gas denitrification process in the field of environmental protection, in particular to a catalytic denitrification process for sintering flue gas partitioned circulating soot Background technique [0002] NOx emissions in the sintering process account for about 45-48% of the total NOx emissions in iron and steel plants. With the development of energy-saving technology for sintering process and the improvement of environmental protection requirements, the utilization of sintering waste heat and denitrification of sintering flue gas have become the key factors to reduce sintering energy consumption. And meet the top priority of environmental protection requirements. [0003] Sintering flue gas circulation is one of the effective means to promote the discharge of sintering flue gas pollutants. Its technical solution is to circulate part of the sintering flue gas from the branch pipe of the bellows or a part of the sintering...

AI Technical Summary

Problems solved by technology

In the sintering machine flue gas purification projects of Japan's Nippon Steel Sumitomo Metal, JFE, South Korea's Posco, and China's Taiyuan Iron and Steel Co., Ltd., there are application cases of activated carbon (coke) adsorption and purification of pollutants in sintering flue gas, but the operation practice shows that the Large technical investment, high operating costs, low denitrification efficiency, and difficult disposal of waste activated carbon seriously restrict the large-scale promotion of this technology.

Selective catalytic reduction (SCR) has high denitrification efficiency, but its one-time investment cost is high (the catalyst cost accounts for 30-40% of the total investment cost), and the existing SCR flue gas denitrification technology is generally 350- It is carried out at 450°C, which consumes a lot of heat energy to heat the flue gas after desulfurization, which additionally increases the operating cost of SCR denitrification

Low-temperature denitrification catalysts are mostly noble metals, which are more expensive and prone to oxygen inhibition and sulfur poisoning

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