Two-stage selective non-catalytic reduction (SNCR) denitrification system and two-stage SNCR denitrification method

Abstract

The invention provides a two-stage selective non-catalytic reduction (SNCR) denitrification system and a two-stage SNCR denitrification method. The system and the method can effectively prolong the residence time of a reductant in a furnace, enhance a mixing effect of the reductant and flue gas, and promote a reduction reaction to be rapidly carried out at a low-temperature section, thereby greatly improving the denitrification efficiency of SNCR and having considerable economic and environmental benefits. The system comprises a boiler; two stages of cyclone separators are arranged on a horizontal flue behind a furnace arch of the boiler in a way of series connection; a first stage SNCR denitrification reactor and a second stage SNCR denitrification reactor are respectively arranged in front of the two stages of cyclone separators; an outlet end of the later cyclone separator is connected with an exit flue; the first stage denitrification reactor is internally provided with a pluralityof main spray guns, and the main spray guns are evenly arranged on the cross section of the horizontal flue in multiple layers; the second stage denitrification reactor is internally provided with ammonia supplement spray guns, and the ammonia supplement spray guns are arranged along the cross section of the horizontal flue.

Description

technical field [0001] The invention relates to the layout of boilers and SNCR denitration devices, in particular to a two-stage SNCR denitration system and method. Background technique [0002] Nitrogen oxides are one of the main pollutants emitted by coal-fired boilers. In recent years, the Ministry of Environmental Protection has imposed stricter requirements on the emission standards of nitrogen oxides. Relying solely on low-nitrogen combustion technology cannot meet environmental protection requirements. It is urgent to find a high-efficiency And economical flue gas denitrification program. [0003] Currently commonly used flue gas denitrification technologies mainly include SCR flue gas denitrification method and SNCR flue gas denitrification method. The SCR flue gas denitrification method uses ammonia as a reducing agent under the action of a catalyst to undergo a reduction reaction with nitrogen oxides in the temperature range of 300-400 ° C, thereby removing nitrog...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the problem of low denitrification efficiency in the existing SNCR denitrification technology, the present invention provides a two-stage SNCR denitrification system and method, which can effectively increase the residence time of the reducing agent in the furnace, improve the mixing effect of the reducing agent and flue gas, and Promote the rapid reduction reaction in the low temperature section, thereby greatly improving the denitrification efficiency of SNCR, which has considerable economic and environmental benefits

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