Abstract:

A Chinese bituminous coal was firstly separated into three density fractions, heavy (>2.0 g·cm-3), medium (1.4—2.0 g·cm-3) and light (<14 g·cm-3) by using the floatsink methodNext,the combustion and pyrolysis of each density fraction were carried out in a laboratoryscale drop tube furnace to understand the emission, elemental composition and formation mechanism of inhalable particulate matter (PM10)PM10 was collected with a 13 stages low pressure impactor (LPI) having aerodynamic cutoff diameter ranging from 10.0 μm to 0.03 μm for a sizesegregated collectionThe experimental results indicated that density affected PM10 emission significantly in combustion,and decreasing coal density led to the formation of more PM10The mineral particle size of the light fraction was the smallest and that of the heavy fraction was the largestThe swelling ratio, total pore volume and BET surface area of char produced from each fraction were differentThose from the light fraction were the largest and those from the heavy fraction were the smallest.The elemental composition of PM10 collected from each density fraction had the same trendIn the submicron particulate matter (PM1): element S+alkali metals+others>refractory metals， in the supermicron particulate matter (PM1—10): the mass percent of refractory metals were greater than 80% and exceeded other three types of element.

摘要：

通过浮选实验先将典型烟煤分成高、中、低3个密度段，然后对3种不同密度原煤在沉降炉内进行热解和燃烧实验，研究原煤密度对颗粒物形成机理和特性的影响。实验采用低压撞击器（LPI）把颗粒物按不同粒径大小从0.03～10.0 μm共分13级，分别采集燃烧后的可吸入颗粒物。实验结果显示：低密度原煤对颗粒物形成的贡献最大，中密度次之，高密度最小，低密度原煤所含矿物质粒度最小，形成的焦的膨胀率、总孔体积和BET表面积最大，高密度原煤所含矿物质粒度最大，形成的焦的膨胀率、总孔体积和BET表面积最小，中密度原煤介于两者之间，3种密度原煤燃烧后形成的PM10颗粒物元素构成的相同点是：对于亚微米颗粒物，元素S＋碱金属元素＋其他元素>难熔元素，对于超微米颗粒物，难熔元素占80%以上，远远大于其他三类元素。