现有挥发性有机物（VOCs）采样标准多针对简单环境与小分子化合物，缺乏针对燃煤烟气高湿、高尘及成分复杂这一特殊环境的采样方法。基于现有固定污染源吸附管采样标准HJ 734—2014《固定污染源废气 挥发性有机物的测定 固相吸附-热脱附/气相色谱-质谱法》，利用改进后的采样系统对丙酮、正己烷、甲苯、乙苯和1-癸烯5种VOCs标准样品和模拟燃煤烟气样品进行采样，研究了不同吸附剂、水分及其他烟气成分对VOCs采样分析的影响。结果表明：多孔聚合物吸附剂(Tenax TA)与硫分子筛吸附剂(Sulficarb)二合一填料填充的吸附管，相对标准偏差为0.01%～2.04%，加标平均回收率均大于80%，更适宜燃煤VOCs的采样。采样系统中除灰装置或除水装置对VOCs影响较小，能保证采样过程数据准确有效。未经过采样系统时，模拟烟气中水分、NO和SO2的存在均会对VOCs的质量和平均回收率产生负面影响，其中1-癸烯受烟气成分影响较大，平均回收率仅达到36%。当NO、SO2质量浓度分别为16～621 mg/m3与40～1 326 mg/m3时，本采样系统能很好地降低水分、NO与SO2对模拟燃煤烟气的影响，为实际燃煤电厂采样提供参考。

The existing volatile organic compounds (VOCs) sampling standards are mostly for simple environments and small molecular compounds,and lack sampling methods for coal-fired flue gas with high humidity,high dust and complex composition. Based on the existing sorbent adsorption-thermal desorption-gas chromatography mass spectrometry sampling standard HJ 734—2014 "Stationary source emission-determination of volatile organic compound-sorbent adsorption and thermal desorption gas chromatography mass spectrometry method"，five kinds of VOCs including acetone,hexane,toluene,ethylbenzene,and 1-decylene,and coal-fired simulated flue gas were sampled by the improved sampling system to investigate the effects of different sorbents,moisture and other flue gas components on VOCs sampling and analysis. The results show that the adsorbent tubes filled with porous polymer adsorbent (Tenax TA) and sulfur molecular sieve adsorbent (Sulficarb) have relative standard deviations of 0.01%-2.04%,and standard average recoveries are more than 80%,which are more suitable for the sampling of VOCs from coal combustion. The ash removal device or water removal device in the sampling system has little impact on VOCs,which can ensure the accuracy and effectiveness of the data in the sampling process. Without the sampling system,the presence of moisture,NO and SO2 in the simulated flue gas can have a negative impact on the average and weight recovery rate of VOCs,among which 1-decene is greatly affected by the flue gas environment and the average recovery rate only reaches 36%. When the mass concentrations of NO and SO2 vary from 16 to 621 mg/m3 and 40 to 1 326 mg/m3,respectively,the sampling system can well reduce the impact of moisture,NO and SO2 on the simulated flue gas,which can provide a reference for the sampling in actual coal-fired power plants.

0 引言

1 试验与分析方法

   1.1 标准样品

   1.2 吸附管

   1.3 采样系统

   1.4 试验仪器

   1.5 试验方案

2 结果与讨论

   2.1 标准曲线

   2.2 不同吸附管对VOCs测定结果的影响

   2.3 采样系统的准确性测试

   2.4 采样系统的必要性测试

   2.5 不同模拟燃煤烟气条件对VOCs测定的影响

3 结论与建议