Synchronous denitration process based on wet ammonia process flue gas desulfurization

Abstract

The invention discloses a synchronous denitration process based on wet ammonia process flue gas desulfurization. The problems such as high operating cost and equipment investment cost, complex process and high energy consumption existing in an existing process are solved. According to the technical scheme, the process comprises the following steps: pressurizing flue gas, feeding the flue gas into a concentrating tower, allowing the flue gas to contact and react with a concentrated solution in the tower, feeding the flue gas out of the concentrating tower into an absorption tower to contact and react with absorption liquid in the tower, feeding a small amount of reacted concentrated solution at the bottom of the concentrating tower into an ammonium sulfate crystallization system, and adding a complexing agent EDTA-Fe (II) or adding EDTA-Na salt and ferrous sulfate according to a molar ratio of 1:1 into the absorption liquid in the absorption tower, so that the concentration of the EDTA-Fe (II &III) in the absorption liquid is 0.015-0.05mol/L; and feeding a small amount of absorption liquid in the absorption tower into the concentrating tower to be mixed with the concentrated solution. The synchronous denitration process disclosed by the invention has the advantages of simplicity, low operating cost and equipment investment, capacity of performing high-efficiency synchronous desulfurization and denitration and low energy consumption.

Description

technical field [0001] The invention relates to the field of flue gas purification, in particular to a synchronous denitrification process based on flue gas wet ammonia desulfurization. Background technique [0002] my country's iron and steel industry has developed rapidly since the 1990s, resulting in a large amount of air pollutants, among which SO 2 And NOx emissions are second only to power plant flue gas. my country's key statistical steel industry SO in 2011 2 The emission is 2.51 million tons, of which SO 2 The emissions reached 2.18 million tons, accounting for more than 87% of the total emissions of iron and steel enterprises, while SO 2 The treatment rate is only 32%. The characteristics of sintering flue gas are large flue gas volume, large amount of dust carried by flue gas, large changes in emission and concentration of sulfur dioxide, large fluctuations in flue gas temperature, complex flue gas components, and high moisture content in flue gas. Compared w...

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Problems solved by technology

[0008] However, on the one hand, although Fe(II)EDTA has high denitrification efficiency, it is expensive, and the formation of 2Fe 2+ It is very uneconomical not to recover the complexing agent after EDTA (NO), and the high cost will make it impossible to be industrially practical;

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