Method for flue gas denitration with iron-carbon composite material as SNCR additive

Abstract

The invention discloses a method for applying a composite material containing iron and carbon as SNCR additive to an SNCR technology, belonging to the technical field of flue gas pollutant control. The method comprises the following steps: firstly, fully mixing 70%-75% of carbon, 15%-18% of Fe3O4 and 10%-12% of FeOOH, conducting calcining for 2 hours by using inert gas at a temperature of 200-300 DEG C to prepare the iron-carbon composite material, conducting cooling, performing drying for 24 hours at a temperature of 110 DEG C, carrying out granulating, screening particles with particle sizes in a range of 20-60 meshes, and sealing and storing the particles; and then removing NOx by using the iron-carbon composite material as the SNCR additive under the conditions that a temperature is 750-1000 DEG C, an oxygen concentration is 2 vol.% and a molar ratio of an NH3 concentration to an NO concentration is 0.5-1. According to the invention, CO and FeOOH generated by carbon in an anoxic environment can provide SNCR with active groups OH and H required by a reaction at low temperature and promote C and NH3 to generate a new reducing agent HCNO; and when the temperature reaches the oxidation temperature of Fe3O4, NO is adsorbed by active sites on the surface of Fe3O4, so reduction of NO to generate N2 is promoted. The iron-carbon composite material is adopted as the additive for SNCR denitration, and existing equipment of a factory does not need to be transformed, so investment cost is low, operation is easy, an SNCR denitration temperature window can be reduced, and meanwhile, a denitration rate can be increased.

Description

technical field [0001] The invention belongs to the technical field of flue gas pollutant control, and in particular relates to a method for using an iron-carbon composite material as an SNCR additive for denitrification. Background technique [0002] The emission of nitrogen oxides into the atmosphere will cause the formation of photochemical smog, which can irritate the human eyes and respiratory tract or induce various respiratory inflammations, endangering human health. A large amount of nitrogen oxides in the air is also an important cause of acid rain. Acid rain will lead to soil acidification, reduce soil fertility, reduce crop production and even become sick. Among the existing denitrification technologies, selective non-catalytic reduction (SNCR) has a short construction period, low investment, and can achieve a high denitrification rate under appropriate flue gas temperature conditions. Commonly used NOx emission reduction technologies. However, in the practical ...

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Problems solved by technology

[0003] From the mechanism of SNCR reaction, it can be seen that ammonia is prone to oxidation reaction at high temperature, which reduces the denitrification rate, so most researches focus on how to broaden the temperature window of SNCR denitrification

The key to the SNCR reaction is the active groups OH and H. Because there are not enough active groups at low temperature, it is impossible to reduce NO. x

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