燃煤电厂烟气中氨脱除及分布机理研究

doi:10.12096/j.2096-4528.pgt.21127

摘要/Abstract

摘要：

在燃煤电厂选择性催化还原(selective catalytic reduction，SCR)脱硝高浓度逃逸氨条件下，对氨在脱硝下游设备中的脱除效率、粉煤灰和浆液中的富集浓度及其分布机理进行研究。对350 MW及600 MW机组分别进行取样分析，结果表明：空预器、电除尘器和湿法脱硫系统对逃逸氨的脱除效率分别为3.37%~6.63%、75.14%~83.28%和36.36%~46.38%，这些下游环保设备对氨的脱除效率高，烟囱入口氨浓度相对脱硝出口氨浓度下降明显；飞灰中的氨含量与飞灰粒径成反比；脱硫净烟气中的氨浓度随原烟气中氨浓度的增大而增大；脱硫系统对氨的脱除效率随浆液pH值的增大而降低。研究结果对机组的环保和经济运行具有重要意义。

关键词: 燃煤电厂, 选择性催化还原(SCR), 逃逸氨

Abstract:

The removal efficiency of ammonia in denitrification downstream equipment, concentration and distribution mechanism of ammonia in fly ash and slurry were studied under the condition of high concentration of ammonia escaping from denitrification by selective catalytic reduction (SCR) in coal-fired power plants. Through sampling analysis of 350 MW and 600 MW units, the results show that: the escaping ammonia removal efficiencies of air preheater, electrostatic precipitator and wet desulphurization system are 3.37%-6.63%, 75.14%-83.28% and 36.36%-46.38%, respectively. The ammonia removal efficiencies of these downstream environmental protection equipment are high, and the ammonia concentration at chimney entrance decreases obviously compared with that at denitrification outlet. The ammonia content in fly ash is inversely proportional to the particle size of fly ash. Ammonia concentration in desulfurized flue gas increases with the increase of ammonia concentration in original flue gas. The removal efficiency of ammonia in desulphurization system decreases with the increase of slurry pH value. The results have great significance to the units’ environmental protection and economic running.

Key words: coal-fired power plant, selective catalytic reduction (SCR), ammonia slip

中图分类号:

TK 09

吉攀. 燃煤电厂烟气中氨脱除及分布机理研究[J]. 发电技术, 2023, 44(3): 392-398.

Pan JI. Study on Removal and Distribution Mechanism of Ammonia in Flue Gas of Coal-fired Power Plant[J]. Power Generation Technology, 2023, 44(3): 392-398.

图/表 10

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参数	1号机组	2号机组
灰分质量分数A_ar/%	27.37	24.53
挥发分质量分数V_ad/%	12.28	12.80
硫分质量分数S_{t， ad}/%	1.68	1.72
低位发热量Q_{net， ar}/(MJ/kg)	20.21	20.77

参数	1号机组	2号机组
灰分质量分数A_ar/%	27.37	24.53
挥发分质量分数V_ad/%	12.28	12.80
硫分质量分数S_{t， ad}/%	1.68	1.72
低位发热量Q_{net， ar}/(MJ/kg)	20.21	20.77

机组编号	负荷/MW	SCR入口NO _x 质量浓度/(mg/m³)	SCR出口NO _x 质量浓度/(mg/m³)
1	300	632	12
1	300	617	36
2	550	696	11
2	550	688	41

机组编号	负荷/MW	SCR入口NO _x 质量浓度/(mg/m³)	SCR出口NO _x 质量浓度/(mg/m³)
1	300	632	12
1	300	617	36
2	550	696	11
2	550	688	41

机组编号	工况	采样点位置
机组编号	工况	SCR出口	APH出口	ESP出口	WESP出口
1	1	17.83	17.23	2.88	1.72
1	2	7.91	7.59	1.65	1.05
2	1	16.44	15.41	3.04	1.63
2	2	5.73	5.35	1.33	0.75