淮南燃煤电厂烟气中颗粒相和气相中多环芳烃的赋存特征

Occurence of polycyclic aromatic hydrocarbons in PM_(10)-and gaseous phases of flue gases emitted from Huainan coal-fired power plant

采集安徽省淮南市3个燃煤发电锅炉排放的气态和颗粒态样品,通过GC-MS测定美国环保局优控的16种多环芳烃(PAHs),并对其残留、赋存和分配特征进行了分析研究.结果表明,PM_(10)相和气相中PAHs的质量浓度范围分别为2.9—7.5μg·m^(-3)和6.0—15.1μg·m^(-3),PAHs的质量浓度明显受到锅炉类型、装机容量与燃烧条件的影响,静电除尘器(ESP)对气相PAHs清除效率较低;PM_(10)相中PAHs主要为中分子量4环和高分子量5环,分别占总PAHs的35.8%—49.3%和16.2%—27.3%,与PM_(10)相相比,气相PAHs主要分布为2—3环,而4—6环PAHs含量较少.脱硫装置有效地提高了高分子PAHs的去除率;PM_(10)相及气相中PAHs分布不均衡,吸收作用主导了PM_(10)相与气相之间的PAHs分配;PAHs单体显示出不同的主导分配机制,主要由于它们之间不同的化学亲和力和蒸气压所导致的.

In this study,16 US EPA priority polycyclic aromatic hydrocarbons（PAHs） in PM10 and gaseous phases emitted from three coal-fired utility boilers in Huainan,Anhui Province were analyzed.The partitioning mechanisms of PAHs between PM10-and gaseous phases were investigated.Results indicate that the concentration ranges of PM10-and gas-phase PAHs in flue gas are 2.9 to 7.5 μg·m^-3 and 6.0 to 15.1 μg·m^-3,in addition,they are primarily influenced by boiler capacity and operation conditions.The removal efficiency of gas phase PAHs through Electrostatic precipitator（ESP） is lower.PM10-phase PAHs are predominated by 4-and 5-ring PAHs,accounting for 35.8%—49.3% and 16.2%—27.3% of total PAHs,respectively.Moreover,gas-phase PAHs are significantly depleted in 4-to 6-ring species and mostly characterized by 2-and 3-ring PAHs.The wet flue gas desulphurization（WFGD） had significant effect on the elimination of PAHs in bothPM10 and gaseous phases,especially for the high molecular weight PAHs.PAH partitioning between PM10 and gaseous phases was dominated by the absorption behavior.Individual PAHs exhibitd different dominant distribution due to their different chemical affinities and vapor pressures.