Device and method for denitration on flue gas by coupling selective non catalytic reduction and catalytic reduction

Abstract

The invention discloses a device and a method for denitration on flue gas by coupling selective non catalytic reduction and catalytic reduction and relates to a technology for removing nitrogen oxides in burned flue gas of fossil fuels. The invention adopts a scheme 1 that the denitration device comprises a plurality of spray guns for spraying a reducing agent, economizer, a mesothermal catalyst and an air preheater, wherein the spray guns are arranged in a furnace in a layered mode; and the economizer, the mesothermal catalyst and the air preheater are arranged in a flue sequentially along the flowing direction of the flue gas. Compared with the prior art, the device and the method mainly utilize the denitration capacity of an SNCR (Selective Non Catalytic Reduction) system, utilize an SCR (Selective Catalytic Reduction) system as supplement and have the characteristics of high denitration efficiency, low ammonia escape rate, equipment conservation, investment reduction, space conservation and the like.

Description

technical field [0001] The invention relates to a method for removing nitrogen oxides in flue gas of fossil fuel combustion, in particular to a flue gas denitrification device coupled with a selective non-catalytic reduction SNCR reaction and a selective catalytic reduction SCR reaction and a method thereof. Background technique [0002] The flue gas produced by fossil fuel combustion contains a large amount of nitrogen oxides. As an acidic gas, nitrogen oxides are one of the air pollutants that form acid rain and acid fog, and have great harm to the ecological environment and human health. Under certain conditions, the nitrogen oxides in the flue gas can undergo a reduction reaction with a nitrogen-containing reducing agent to generate water and nitrogen that will not cause secondary pollution to the environment. This reduction reaction can occur at a relatively high temperature without catalyst catalysis. This process is called Selective Non-Catalytic Reduction Technology ...

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Problems solved by technology

[0003] SNCR technology has the advantages of convenient installation, simple equipment, and low investment cost, but it has disadvantages such as low denitrification efficiency, high ammonia escape rate, and secondary pollution.

The SCR technology has the advantages of high denitrification efficiency and low ammonia escape rate, but it requires a large amount of catalyst and the catalyst is expensive, and it also requires a large installation space, high investment and operating costs

In addition, due to the limitation of the original boiler site, it is very difficult to transform the old boiler into SCR

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