Denitration agent for oxidized flue gas and denitration process thereof

Abstract

The invention relates to a denitration agent for oxidized flue gas and a denitration process thereof. After the flue gas is oxidized by an oxidizing agent, part of NO is converted into NO2; the denitration agent is added to the bottom of a slaked lime bin or a circulating fluidized bed semi-dry reactor, the denitration agent comprises a Ca-based denitration agent and a modified Ca-based denitration agent, and the Ca-based denitration agent comprises four core components including calcium sulfite, calcium hydroxide, calcium carbonate and calcium sulfate; and according to the modified Ca-based denitration agent, a small amount of modifier, such as one or more of a sulfenyl denitration enhancer, a free radical trapping agent and a phase transfer agent, is added on the basis of the four core components. The synergistic effect of the four core components of the Ca-based denitration agent realizes removal of NO2 and NO, and compared with the traditional technology of simultaneous desulfurization and denitration of slaked lime, the method provided by the invention can significantly improve the removal effect of NO2 and remove part of NO, reduce the use amount and escape of O3, and improve the quality of desulfurization and denitration slag.

Description

technical field [0001] The invention belongs to the field of flue gas pollution control, and relates to a powdery Ca-based denitrification agent used for oxidized flue gas and a denitrification process thereof. Background technique [0002] Nitrogen oxides (NOx, including nitrogen dioxide (NO 2 ) and nitric oxide (NO)) cause a series of problems such as photochemical smog, acid rain and the hole in the ozone layer, causing huge damage to the environment. The country's emission requirements for nitrogen oxides are becoming more and more stringent, and a policy of ultra-low emission of nitrogen oxides has been proposed (NOx in outlet flue gas≤50mg / Nm 3 ). Ammonia Selective Catalytic Reduction Technology (NH 3 -SCR) to achieve ultra-low emissions. However, this technology is only suitable for flue gas at a temperature of 300-400°C. Nowadays, the flue gas temperature of sintering machines, industrial boilers, glass kilns, etc. is below 180 °C, which is not suitable for dire...

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Problems solved by technology

[0003] However, in the simultaneous desulfurization and denitration of flue gas oxidation + CFB semi-dry method, SO 2 Get better absorption, but NO 2 It is still difficult to absorb, and unoxidized NO is even more difficult to absorb. It is difficult for most projects to achieve ultra-low emissions of nitrogen oxides, accompanied by yellow smoke or even red smoke emissions (NO 2 color) phenomenon; some projects also have ultra-low emissions of nitrogen oxides, but, due to the NOx in the exhaust 2 Concentration>20mg / Nm 3 The phenomenon of yellow smoke appears; some projects also use a large amount of ozone to oxidize NO to N 2 o 5 , and then absorb N 2 o 5 achieve denitrification, however, O 3 The excess is serious, the operating cost is too high, and there are serious O 3 escape

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