摘要
燃煤电厂石灰石-石膏湿法脱硫系统出口的净烟气为45℃~55℃的饱和湿烟气,经烟囱排入环境中会形成白雾,采用循环冷却水直接喷淋净烟气可以有效降低烟气温度,使烟气中的气态水冷凝为液滴进入循环水系统从而减缓白雾,但烟气冷凝水进入循环水会对水系统产生一定的影响。以天津某2×500 MW超临界燃煤发电机组为例,采用现场测试喷淋系统进出口水质方法定量计算了烟气冷凝水带入循环水系统中的H^(+)离子总量,分析了烟气冷凝水对循环水水质(如碱度、SO_(4)^(2-)、氨氮、氯离子、铁和浊度等)的影响。结果表明,燃煤发电机组负荷329 MW~453 MW,喷淋系统循环水量800 m^(3)/h,循环水碱度下降0.22 mmol/L~0.63 mmol/L,烟气中酸性组分溶于循环水引入的H^(+)离子量约176 mol/h~504 mol/h,循环水氨氮浓度增加0.14 mg/L~0.55 mg/L,氨氮在循环水发生硝化反应产生的H^(+)离子量约16 mol/h~63 mol/h,循环冷却水直接喷淋净烟气引入循环水系统的H^(+)离子总量为230 mol/h~567 mol/h;烟气冷凝水对循环水氯离子、硬度、浊度和铁基本无影响。通过对喷淋系统进出口水质定量计算提出循环冷却水系统运行控制方案,根据库水来水水质,通过调节弱酸水和库水的补水比例来实现控制循环水系统补水碱度约为1.0mmol/L,并通过现场试验进行了验证。
The net flue gas at the outlet of limestone gypsum wet desulfurization system of coal-fired power plant is saturated wet flue gas of 45℃~55℃,which will form white fog when discharged into the environment through the chimney.Direct spraying of the net flue gas with circulating cooling water can effectively reduce the flue gas temperature,so that the gaseous water in the flue gas can be cooled and condensed into droplets into the circulating water system to eliminate the white fog.However,the flue gas condensate entering the circulating water system will have a certain impact on the water system.Taking a 2×500MW supercritical coal-fired unit in Tianjin as an example,the total amount of H+ions brought into the circulating water system by flue gas condensate was quantitatively calculated by using the method of on-site testing the water quality at the inlet and outlet of the spray system,and the impact of flue gas condensate on the circulating water quality(such as alkalinity,SO_(4)^(2-),ammonia nitrogen,chloride ion,iron and turbidity)was analyzed.The results showed that under different load range(329 MW-453 MW),the circulating water volume of spray system was 800 m^(3)/h.The alkalinity of the circulating water in the plume control system decreased by 0.22mmol/L to 0.63mmol/L,and the H^(+)amount of the acid components dissolved in the flue gas introduced by the circulating water was about 176 mol/h~504 mol/h.The ammonia concentration in the circulating water of the air tower spray system increased by 0.14mg/L to 0.55 mg/L,and the amount of H^(+)generated by nitrification of ammonia nitrogen in the circulating water was about 16 mol/h-63 mol/h.The total amount of H^(+)introduced into the circulating water system by the plume control system was 230 mol/h-567 mol/h.The average value was about 365 mol/h.Flue gas condensate had little effect on chloride ion,hardness,turbidity and iron in circulating water.Based on the water quality of the inlet and outlet of the spray system in the air tower,the acid amount of plume condensed water brought into the circulating cooling water system was calculated,and the operation control strategy of the circulating cooling water system was put forward.According to the water quality of reservoir water,the water refill basicity of the circulating water system was controlled to be about 1.0mmol/L by adjusting the water refill ratio of weak acid water and reservoir water,which was verified by field test.
作者
张宁
张翠伶
张利权
于学斌
余耀宏
姜琪
胡大龙
ZHANG Ning;ZHANG Cuiling;ZHANG Liquan;YU Xuebin;YU Yaohong;JIANG Qi;HU Dalong(Xi'an TPRI Water Management&Environment Protection Co.,Ltd.,Xi’an TPRI Water-Management&Environmental Protection Co.,Ltd.,State Key Laboratory of High-Efficiency Flexible Coal Power Generationand Carbon Capture Utilizationand Storage,Shannxi Xi'an 710054,China;Xi'an Yitong Thermal Technology Service Co.,Ltd.Shannxi Xi'an 710054,China;Tianjin Guohua Panshan Power Generation Co.LTD.,Tianjin 301900)
出处
《电力科技与环保》
2022年第6期525-532,共8页
Electric Power Technology and Environmental Protection
基金
中国华能集团有限公司科技项目(HNKJ21-HF327)。
关键词
烟气冷凝水
碱度
循环水
控制方案
condensed flue gas
alkalinity
circulating cooling water
operation strategy
