民用燃煤不同燃烧阶段细颗粒物排放特征

研究了民用燃煤在不同燃烧阶段排放PM_2.5的质量浓度分布特征.结果表明，散煤与正烧炉在旺火阶段排放颗粒物粒径主要集中在0.2μm以下（d₅₀=0.15μm），加煤和封火阶段在0.2~0.5μm （d₅₀=0.38mm），质量占比46.6%~68.97%.型煤与正烧炉在各阶段排放的颗粒物均以0.2μm以下颗粒物为主，质量占比44.64%~56.24%.扫描电镜（SEM）观察到燃煤排放PM_2.5为大量超细颗粒物聚集形成的簇团状结构.用碳平衡法计算得到散煤加煤阶段的PM_2.5排放因子为4.72g/kg，分别是旺火和封火阶段的12和11倍.将散煤更换为型煤，能够使得加煤阶段的PM_2.5排放因子减少90.9%，从而显著降低PM_2.5排放.

Emission characteristics of fine particulate matter at different combustion phases of residential coal

The mass distribution characteristics of PM_2.5 particles during different combustion phases of residential coal were studied in this work. PM_2.5 particles during the flaming phase of burning bituminous coal in an over-fire stove were mainly particulate matters (PM) with diameter below 0.2μm (d₅₀=0.15μm) and peaked at 0.2~0.5μm (d₅₀=0.38μm) during the fuel-adding and smoldering phases. Their mass ratio was between 46.6% and 68.97%. On the other hand, PM emitted from the whole process of burning briquettes in an under-fire stove were mainly below 0.2μm, and the mass ratio was 44.64%~56.24%. The scanning electron microscopy (SEM) observation showed that the PM_2.5 particles emitted from coal-burning were cluster-like structure formed by the aggregation of a large number of ultrafine particles. Also, the emission factor (EF) of PM_2.5 calculated by the carbon balance approach of the bituminous and over-fire stove in the fuel-adding phase was 4.72g/kg, which was 12 and 11 times of that in the flaming and smoldering phases respectively. The replacement of bituminous to briquette will result in the reduction of PM_2.5 EFs by 90.9% during the fuel-adding phase, leading to a significant decrease in PM_2.5 emission.