民用燃煤颗粒物及多环芳烃排放特性

Emissions of particulate matter and polycyclic aromatic hydrocarbons from household coal combustions

民用煤的不完全燃烧是大气中颗粒物及其多环芳烃的主要排放源之一,对大气环境和人体健康均造成了严重危害。为了评价不同"煤炉匹配"方式对16种优先控制的高毒性多环芳烃(PAHs)排放的影响,研究了烟煤块煤、烟煤型煤、无烟煤型煤和兰炭4种不同燃料在代表性的3种民用炉具(正烧炉、反烧炉和解耦燃烧炉)中的颗粒物(PM)及其PAHs的排放特性。根据实验结果进一步计算了毒性当量,并与有关文献报道数据进行了对比。在解耦燃烧炉中,烟煤型煤PM和PAHs的排放因子(EFPM和EFPAHs)(0.50 g/kg、403.2μg/kg)分别是烟煤块煤(3.65 g/kg、989.6μg/kg)、兰炭(1.08 g/kg、622.3μg/kg)、无烟煤型煤(2.10 g/kg、148.3μg/kg)的13.7%、46.3%、23.8%和42.3%、67.3%、282.3%,除了EFPAHs高于无烟煤型煤之外,EFPM和EFPAHs均明显低于其他煤种;以烟煤块煤为原料,在解耦炉中燃烧的EFPM和EFPAHs(3.65 g/kg、989.6μg/kg)分别是正烧炉(46.58 g/kg,16182.3μg/kg)和反烧炉(6.00 g/kg,11749.4μg/kg)的7.8%、60.8%和6.1%、8.4%,说明炉具燃烧形式对EFPM和EFPAHs的影响大于燃料种类;三种"煤炉匹配"方式(解耦炉+烟煤型煤、正烧炉+兰炭、正烧炉+无烟煤型煤)的EFPM和EFPAHs(0.50 g/kg、1.62 g/kg、1.32 g/kg和403.2μg/kg、1196.5μg/kg、66.5μg/kg)均低于传统正烧炉+烟煤块煤(46.58 g/kg,16182.3μg/kg)以及近年来大部分文献报道的数据(0.68~24.3 g/kg,680~137700μg/kg)。结果表明,炉具燃烧形式和煤质特性均是影响EFPM和EFPAHs的主要因素,但高效的燃烧方式能够大幅降低煤质特性对污染物排放造成的影响,通过对炉具的不断改进以及采用合适的"煤炉匹配"技术,能够对我国储量巨大的烟煤资源合理、有效和清洁地利用。

Incomplete combustion of household coal is one of the major emission sources of particulate matter(PM)and polycyclic aromatic hydrocarbons(PAHs), which have caused serious harmful impacts on the atmospheric environment and human health. To evaluate the effects of coal types and their combustion methods on the PM and PAHs emissions, four different coals, namely bituminous chunk coal, bituminous coal briquette, anthracite coal briquette and semi-coke were respectively combusted in three typical household cooking and heating coal stoves(i.e. updraft stove, downdraft stove and decoupling combustion stove). Based on the experimental results, the toxicity equivalents(TEs) were calculated and compared with the data reported in the literature. With the decoupling combustion stove, the emission factors of particulate matter(EFPM) and polycyclic aromatic hydrocarbons(EFPHAs)were measured to be 0.50 g/kg and 403.2 μg/kg for the bituminous coal briquette, 3.65 g/kg and 989.6 μg/kg for the bituminous chunk coal, 1.08 g/kg and 622.3 μg/kg for the semi-coke and 2.10 g/kg and 148.3 μg/kg for the anthracite coal briquette. Clearly, the bituminous coal briquette combustion produced significantly lower PM and PAHs than combustion of other coal types, except for the EFPAHsof the anthracite coal briquette. With the same bituminous chunk coal combusted, the EFPMand EFPHAswere determined as 3.65 g/kg, 989.6 μg/kg for the decoupling stove, 46.58 g/kg and 16182.3 μg/kg for the updraft stove, and 6.00 g/kg and 11749.4 μg/kg for the downdraft stove, strongly suggesting that the combustion methods have an even bigger impact than fuel type on the emissions of PM and PAHs. Furthermore, the experimental data showed that the decoupling stove burning the bituminous coal briquette produced the lowest PM and PAHs, with the EFPMand EFPHAs being 0.50 g/kg, 403.2 mg/kg,followed by the updraft stove burning the semi-coke(EFPM1.62 g/kg, EFPHAs1196.5 μg/kg) and the updraft stove burning the anthracite coal briquette( EFPM1.32 g/kg, EPPHAs66.5 μg/kg). All of these were significantly lower than the data from the updraft stove burning bituminous chunk coals, which were 46.58 g/kg and 16182.3 μg/kg from this study and 0.68-24.3 g/kg and 680-137700 μg/kg reported in the literature. The results indicated that the emissions of PM and PAHs were affected by both the combustion methods and the coal quality characteristics, and the efficient combustion played a greater role in reducing the emissions. The "coal stove matching" technology can make rational, effective and clean utilization of China’s huge reserves of bituminous coal resources.