Desulfurization and denitrification system and method by adopting ozone oxidation in cooperation with ammonia method

Abstract

The invention provides a desulfurization and denitrification system and method by adopting ozone oxidation in cooperation with an ammonia method. The desulfurization and denitrification system comprises a first absorption device and a second absorption device which are sequentially communicated in the flue gas flow direction. An ozone generation device is connected into an inlet flue of the firstabsorption device; the interior of the second absorption device is sequentially divided into a circulating spraying area and at least two layers of multi-effect spraying areas from bottom to top in the flue gas flowing direction, the circulating spraying area is externally connected with at least two absorbent storage tanks, the absorbent storage tanks are independently connected into the multi-effect spraying areas respectively, and the absorbent storage tanks supply absorbents to the circulating spraying area and the multi-effect spraying areas respectively; and the circulating spraying areais externally connected with a recovery unit. By adopting a double-tower structure for absorption, the retention time of the absorbent in the tower is prolonged, the contact time with flue gas is prolonged, and the desulfurization and denitrification efficiency is improved. A mixed absorbent of ammonia water and a calcium-based absorbent is adopted, and NOx in the flue gas is converted into chemical fertilizer and gypsum with higher additional value.

Description

technical field [0001] The invention belongs to the technical field of desulfurization and denitrification, and relates to a desulfurization and denitrification system and method, in particular to a desulfurization and denitrification system and method of ozone oxidation and ammonia method. Background technique [0002] In recent years, flue gas SO in my country's iron and steel, coking, metallurgy and other non-electric industries 2 , NO x The emission reduction has received widespread attention. National and local governments continue to introduce increasingly stringent emission standards, which puts the industry under enormous pressure to reduce emissions. Taking steel and coking industries as examples, sintering flue gas and coke oven flue gas are the main SO 2 and NO x Emission source. The emission temperature of these flue gases is generally low (150-250°C), which cannot meet the temperature window of the traditional SCR process. Therefore, the SCR denitrification...

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Problems solved by technology

[0006] However, there are still some problems in ammonia desulfurization at present: the circulating fluid contains 2 Ammonium sulfite with absorption function also contains a large amount of ammonium sulfate, which causes a large amount of energy consumption and waste of circulating liquid pump power; ammonia absorbent consumes a lot and has the problem of ammonia escape; the outlet flue gas is easy to carry small droplets and aerosol, it is difficult to remove completely; the quality of the by-product ammonium sulfate is not high, the overall equipment investment and operating costs are relatively high, etc.

[0011] When there are sulfur dioxide and nitrogen oxides in the flue gas at the same time, there are a series of problems such as the mutual influence of the two processes, high energy consumption and operating costs, large floor area, and high equipment investment for the separate treatment of sulfur dioxide and nitrogen oxides.

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