SCR选择性催化还原脱硝技术/Selective Catalytic Reduction (SCR) Denitration Technique
系统原理:

在锅炉尾部烟道中280℃~420℃的烟温部位,喷入氨气作为还原剂,与烟气充分混合,在特定催化剂作用下,还原剂有选择地将烟气中的NO、NO2还原成无毒无污染的N2和H2O,从而去除烟气中的NOX 。

其主要反映如下:
4NH3+4NO+O2→4N2+6H2O
4NH3+4NO+O2→3N2+6H2O

主要技术指标及求:
脱硝效率大于90%
逃逸氨小于3ppm SO2/SO3
氧化率小于1%
系统阻力小于1000Pa。

 
SCR烟气脱硝系统图   SCR Flue Gas Denitration System Figure
1 Boiler   2 Heat exchanger    3 Air     4  Electric precipitator  5 SO2 absorption tower  6 SCR reactor  7 Catalyst  8 Atomizer  9 Air& ammonia commingler   10 Ammonia tank

System principle:

Inject ammonia gas to the location with a temperature of 280℃to 420 ℃ in the tail flue of the boiler. The ammonia gas is used as reducing agent, and it’s fully mixed with the flue gas. Under the function of certain catalyst, reducing agent selectively restores the NO and NO2 in the flue gas into non-toxic, non-polluting N2 and H2O, thus removing the NOX in the flue gas. 

The main reactions are as follows:
4NH3+4NO+O2→4N2+6H2O
4NH3+4NO+O2→3N2+6H2O

Main technique indexes and requirements:
Denitration efficiency should be more than 90%
Ammonia escape should be less than 3ppm
Oxygenation rate of SO2 or SO3 should be less than 1%
System resistance should be less than 1000Pa
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