超低排放燃煤机组SO3和NH3生成及迁移规律研究Research on the Formation and Migration Characteristics of SO3 and NH3 in Ultra-low Emission Coal-fired Units
李文华,吴贤豪,陈彪,胡剑利
LI Wenhua,WU Xianhao,CHEN Biao,HU Jianli
摘要(Abstract)：
研究不同机组负荷、还原剂制备方式下超低排放燃煤机组SO_3和NH_3生成及迁移规律,结果表明:负荷的升高促进SCR(选择性催化还原)系统内SO2转化为SO_3,也会促进氨逃逸上升;机组负荷的升高抑制SO_3和NH_3在空预器段迁移;3种还原剂制备方式的机组,SO_3迁移比例在空预器为1.5%～10.4%,在LLT-ESP(低低温电除尘器)为33.7%～53.9%,在FGD(脱硫塔)为17.0%～29.3%; NH_3在空预器和LLT-ESP的迁移比例分别为23%～50%和50%～67%,进入FGD量极少;还原剂制备方式短时对NH_3和SO_3生成及迁移影响不明显,长期运行可能造成氨逃逸上升,进而影响SO_3迁移。
In this paper, the formation and migration characteristics of SO_3 and NH_3 in ultra-low emission coal-fired units under different unit loads and reductant preparation methods are studied. The results show that load increase accelerates the conversion of SO2 to SO_3 in a selective catalytic reduction(SCR) system, and also increases the escaped ammonia. The increase of unit load inhibits the migration of SO_3 and NH_3 in the air preheater. The migration ratios of SO_3 in air pre-heater, LLT-ESP(low-low temperature electrostatic precipitator), and FGD(flue gas desulfurization) of different reductant preparation methods units are respectively 1.5%～10.4%, 33.7%～53.9%, and 17.0%～29.3% of the total SO_3. The migration ratios of NH_3 in air pre-heater and LLT-ESP of different reducing agent preparation methods units are 23% ～50% and 50% ～67% respectively with a small amount of NH_3 entering FGD. The preparation method of the reductant has no obvious impact on the generation and migration of NH_3 and SO_3 in a short time, but its long-term operation may cause ammonia escape increase, which in turn affects the SO_3 migration.
关键词(KeyWords)：
超低排放;燃煤机组;SO_3;NH_3;生成;迁移
ultra-low emission;coal-fired units;SO_3;NH_3;formation;migration
基金项目(Foundation): 浙江省能源集团2019年科技项目(ZNKJ-2019-032)
作者(Author):
李文华,吴贤豪,陈彪,胡剑利
LI Wenhua,WU Xianhao,CHEN Biao,HU Jianli
DOI: 10.19585/j.zjdl.202108014
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