脫硫塔(ta)工(gong)作原理 
SCR煙(yan)氣(qi)(qi)脫硝裝置(zhi)布置(zhi)在鍋爐或窯爐之后，裝置(zhi)內溫度應控(kong)制在290℃-410℃之間(jian)。當含NOx煙(yan)氣(qi)(qi)進(jin)入(ru)到裝置(zhi)，通過(guo)催化(hua)裝置(zhi)時，與(yu)噴(pen)(pen)氨(an)(an)(an)(an)格柵噴(pen)(pen)出的(de)氨(an)(an)(an)(an)接觸，發生(sheng)催化(hua)還(huan)原反(fan)(fan)應。若采用液(ye)氨(an)(an)(an)(an)作(zuo)為還(huan)原劑，需將液(ye)氨(an)(an)(an)(an)蒸發成(cheng)(cheng)氣(qi)(qi)氨(an)(an)(an)(an)，與(yu)稀釋(shi)風機送(song)來的(de)空氣(qi)(qi)混(hun)合(he)成(cheng)(cheng)氨(an)(an)(an)(an)體積(ji)小于5%的(de)混(hun)合(he)氣(qi)(qi)體，通過(guo)噴(pen)(pen)氨(an)(an)(an)(an)格柵噴(pen)(pen)入(ru)煙(yan)氣(qi)(qi)中。若采用尿素作(zuo)為還(huan)原劑，尿素制成(cheng)(cheng)溶液(ye)噴(pen)(pen)入(ru)熱解(jie)器，與(yu)高溫空氣(qi)(qi)接觸，反(fan)(fan)應生(sheng)成(cheng)(cheng)氣(qi)(qi)氨(an)(an)(an)(an)，輸送(song)至噴(pen)(pen)氨(an)(an)(an)(an)格柵。 
方程(cheng)式為(wei)：4NH3+4NO+O2→4N2+6H2O 或 
尿素(su)熱解制氨方程(cheng)式：(NH2)2CO+H2O→2NH3+CO2 
   終(zhong)將NOx還(huan)原成N2排出。 
SNCR爐(lu)(lu)(lu)內脫(tuo)硝系統(tong)是(shi)(shi)在(zai)鍋爐(lu)(lu)(lu)或(huo)(huo)窯爐(lu)(lu)(lu)內噴入(ru)還(huan)原劑(ji)液(ye)氨或(huo)(huo)尿素溶(rong)液(ye)，在(zai)鍋爐(lu)(lu)(lu)內與NOx發(fa)生(sheng)氧化還(huan)原反(fan)應的一種脫(tuo)硝方法。這(zhe)種方法優點(dian)是(shi)(shi)：運行穩定(ding)、投資少;缺點(dian)是(shi)(shi)：還(huan)原劑(ji)的浪費比較多，脫(tuo)硝的效(xiao)率也相對偏低(di)，在(zai)40-60%，溫(wen)度范圍須控制在(zai)800-1200℃之間。