燃煤电厂烟气中SO3排放控制中试研究

燃煤电厂SO₃排放造成严重环境问题，本文利用某电厂污染物脱除中试平台对神华煤燃烧烟气中的SO₃的生成和脱除特性进行了系统研究。结果表明，采用选择性催化还原法（selective catalytic reduction，SCR）的脱硝反应器中烟气SO₂/SO₃的转化率随反应器入口烟气温度的增大而增大。低低温电除尘器（low-low temperature electrostatic precipitator，LLT-ESP）对SO₃的脱除效率随入口烟气温度的增加而减小；湿法脱硫系统（wet flue gas desulfurization，WFGD）的喷淋量达到一定程度后，继续增加喷淋量对提升烟气中SO₃的脱除效果并不明显。当SCR反应器、LLT-ESP入口烟气温度分别为290℃和130℃，WFGD系统3层喷淋层运行时，SO₃的脱除效率稳定在75%~80%，此时，NO_x和SO₂排放浓度远低于超低排放要求。

A Pilot-scale Research on SO3 Control in Flue Gas of Coal Fired Power Plant

SO₃ emission from coal fired power plant causes serious environment issues. In this paper, the generation and removal of SO₃ in flue gas was investigated on a pilot-scale platform of multi-pollutant removal in a Beijing power plant where the Shenhua coal was combusted. The results showed that increasing the inlet temperature of Selective Catalytic Reduction (SCR) reactor led to an increase in the conversion rate of SO₂/SO₃. The SO₃ removal efficiency of low-low temperature electrostatic precipitator (LLT-ESP) decreases with the increase of inlet flue gas temperature. No obvious effect on improving the removal efficiency of SO₃ with a further increase in the amount of the slurry of the wet flue gas desulfurization (WFGD) system. SO₃ removal efficiency could be maintained in 75 % and 80 % when 3 circulating pumps was in operation and the inlet temperature of SCR and LLT-ESP were 290℃ and 130℃ respectively. Under this circumstance, the emission concentrations of NO_x and SO₂ were far below the ultra-low emission requirements.