晋城煤粉中硫的形态、分布及对煤灰熔融性影响的研究

选取山西晋城煤研究煤粉中硫存在形态、分布规律及其对煤灰熔融性的影响。采用浮沉法将煤粉分选成<1.6、1.6-1.7、1.7-2.0和>2.0 g/cm³四个密度级别子样,分析各子样的硫含量、赋存形态及分布规律;测定了不同密度子样煤灰熔融性,并将>2.0 g/cm³密度级别子样加热到450、815、1000和1300℃,研究煤粉中硫受热挥发及其对灰熔融温度的影响规律,并通过XRD和XRF分析进行机理研究。结果表明,晋城煤粉中硫在各密度子样中分布不均匀,在>2.0 g/cm³密度级中含量最高;随密度提高,各子样中有机硫含量快速下降,而硫酸盐硫、硫铁矿硫含量均显著上升。随灰化温度提高,原煤及各密度级别子样硫含量均下降,其中,450℃挥发87%,1300℃基本挥发完全。不同密度子样熔融温度不同,>2.0 g/cm³样品灰熔融温度最低;随灰化温度提高煤灰熔融温度升高。机理研究表明,不同密度子样灰熔融温度发生分化主要是其化学组成不同造成的,而>2.0 g/cm³

Form and distribution of sulfur in pulverized Jincheng coal and their influence on its ash fusibility

Forms and distribution of sulfur in pulverzied Jincheng coal were analyzed, and their influence on ash fusion temperature (AFT) was studied. With the float-sink method, the whole coal was separated into four density fractions, i.e. <1.6, 1.6-1.7, 1.7-2.0 and >2.0 g/cm³. The distribution of sulfur content and their forms were analyzed. SO₃ content and AFT of the coal samples ashed at 450, 815, 1000, and 1300℃ were determined. XRF and XRD were used to reveal the mechanism. The results show that sulfur in pulverized Jincheng coal is not evenly distributed in different density fractions, mainly concentrated in >2.0 g/cm³. With increase of the density, content of organic sulfur decreases rapidly, while those of sulphate sulfur and pyrite increase significantly. With increasing ashing temperature, sulfur contents in the whole coal and density fractions decrease. At 450℃, 87% sulfur is vaporized and at 1300℃ almost all sulfur is vaporized. Different density fraction shows different AFT, with >2.0 g/cm³ having the lowest AFT. Besides, AFT of >2.0 g/cm³ increases with rising ashing temperature. Mechanism study shows that the differentiation of AFT in different density fraction can be attributed to their chemical composition. The increase of AFT of >2.0 g/cm³ with ashing temperature is mainly due to sulfur SO₃ content in the ash residual.