为了解不同容量燃煤机组烟气挥发性有机物(VOCs)的排放特性和不同尾部空气污染物控制设备(APCDs)对VOCs的控制作用,在福建省国投云顶湄洲湾电力公司400MW亚临界对冲燃烧机组和1 000 MW超超临界切圆燃烧机组进行在线法和离线法采样测试,获取烟气中甲烷、非甲烷总烃和其他VOCs的全流程浓度。结果表明,1 000 MW机组SCR前的非甲烷总烃质量浓度(24.66 mg/m3)低于400 MW机组(33.36 mg/m3)。由于1 000 MW机组负荷和炉膛温度高,且煤在切圆燃烧炉内比对冲燃烧停留时间长,故煤燃烧更彻底。两机组SCR系统均能脱除超过70%的非甲烷总烃,400 MW和1 000 MW机组的SCR脱除效果分别为88.43%和74.32%。而在静电除尘过程(ESP)中,高压静电场可能会导致飞灰释放部分VOCs,增加烟气VOCs浓度。经所有APCDs后,400 MW机组和1 000 MW机组的VOCs排放质量浓度分别为8.40和8.47 mg/m3,整体脱除率为73.98%和63.02%,几乎未检出甲烷。离线测试结果:印尼煤燃烧后VOCs主要为正己烷、苯系物和苯甲醛。各固体样品(如煤、灰、石膏)有机物浓度分析显示,VOCs种类与机组大小无明显关联。这些发现有助于深入理解燃煤电厂对空气质量影响及优化污染控制设备设计。燃煤电厂实际运营中需依具体情况优化污染控制设备,以达到最大脱除效果,也需考虑机组大小和运行效率,有效控制VOCs排放。

In order to understand the emission characteristics of volatile organic compounds (VOCs) in the flue gas of coal-fired units withdifferent capacities and the control effect of air pollutant control equipment (APCDs) in different tails on VOCs, online and offline samplingtests were carried out at the 400 MW subcritical offset combustion unit and 1 000 MW ultra-supercritical tangential combustion unit of Yunding Meizhou Bay Electric Power Company in Fujian Province. Theses tests aimed to obtain the whole-process concentrations of methane,non-methane total hydrocarbons and other VOCs in flue gas. The results show that the total non-methane hydrocarbon concentration before SCR of 1 000 MW unit (24.66 mg/ m3) is lower than that of 400 MW unit (33.36 mg/ m3). This disparity can be attributed to the higherload and furnace temperature of the 1 000 MW unit, along with the prolonged residence time of coal in the tangential combustion furnace, resulting in more thorough coal combustion. The SCR system of the two units can remove more than 70% of the total non-methane hydrocarbon, with removal rates of 88.43% for 400 MW unit and 74.32% for 1 000 MW unit, respectively. In the electrostatic dust removal (ESP)process, the high voltage electrostatic field may cause the fly ash to release some VOCs, thus increasing the VOCs concentration in theflue gas. Following the implementation of all APCDs, the VOCs emission concentration of 400 MW unit and 1 000 MW unit is 8.40 mg/ m3and 8.47 mg/ m3, respectively, with the overall removal rate of 73.98% and 63.02%. Notably, almost no methane is detected. The offline testresults show that the main components of VOCs after coal combustion in Indonesia are n-hexane, benzene series and benzaldehyde. The organic content analysis of various solid samples (such as coal, ash, gypsum) shows no obvious correlation between VOCs type and unit size.These findings have important significance for further understanding the impact of coal-fired power plants on air quality and optimizing thedesign of pollution control equipment. In actual operation of coal-fired power plants, pollution control equipment should be optimized according to specific conditions to achieve the maximum removal effect. It is also necessary to consider the unit size and operating efficiency to effectively control VOCs emissions.

0 引言

1 装置和方法

   1.1 电厂概况

   1.2 采样过程

   1.3 分析方法

   1.4 固体样品采样及分析方法

   1.5 质量控制

2 结果与讨论

   2.1 烟气中在线采样数据分析

   2.2 烟气中离线采样数据分析

   2.3 固体样品中甲烷和非甲烷总烃浓度

3 结论