Effect of flotation fractions of long-flame coal on regulation of sulfur and coke reactivity during pyrolysis of high-sulfur coking coal
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摘要: 采用重介质分选法得到长焰煤不同密度级分选组分,利用红外、拉曼、热重、基式流动度、静态氮吸附仪、X射线衍射仪等手段分析研究了不同分选组分对高硫炼焦煤热解过程中硫变迁及焦反应性的影响。结果表明,低密度组分含有较多的脂肪侧链,结构有序度低,而矿物质和惰质组则富集于高密度组分中。低密度级组分由于碱性矿物质含量少,脂肪侧链多,与高硫炼焦煤共热解的脱硫率明显高于高密度组分。低密度组分中的中等分子量组分对胶质体的性质影响较小,高密度组分的矿物质和惰性组分对胶质体的劣化作用更加明显,同时使焦样的微晶结构有序度降低,缺陷位增多,粒焦的反应性升高。Abstract: The flotation fractions of a long-flame coal were obtained by heavy medium separation method, and its effect on regulation of sulfur and coke reactivity during pyrolysis of high-sulfur coking coal were investigated by FT-IR, Raman, TG, Gieseler fluidity, N2 adsorption, XRD. The results show that the low density fractions contain more aliphatic side chains and unstable aliphatic structure, while the high-density fractions show higher amount of minerals and inert components. Low density fractions have the highest sulfur removal rate due to lower content of alkaline minerals and more aliphatic side chains. The medium molecular weight component in the low density fractions has little effect on properties of metaplast. Higher minerals and inert components in high-density fractions deteriorate the metaplast more obviously. Meanwhile, order of the coke's microcrystalline structure is reduced and the defect sites increase, and consequently, reactivity of the coke increases.
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Key words:
- long-flame coal /
- flotation fraction /
- pyrolysis /
- coke reactivity /
- sulfur content
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表 1 实验用煤的分析数据
Table 1 Analysis parameter of coal samples
Sample Proximate analysis w/% Ultimate analysis w/% G Y/mm Mad Ad Vdaf Cdaf Hdaf Ndaf Sd O* LL 0.20 9.76 21.50 88.49 4.69 1.42 1.94 3.25 85.00 16.50 MHL 3.54 4.90 37.63 81.61 4.99 1.07 0.34 11.97 10.00 − note: ad: air dried basis; d: dry basis; daf: dry and ash-free basis; *: by difference 表 2 实验用煤的灰成分分析
Table 2 Ash composition of coal samples
Sample Ash composition w/% R SiO2 Al2O3 Fe2O3 CaO MgO TiO2 SO3 K2O Na2O P2O5 LL 48.70 38.96 4.79 1.80 0.18 1.52 1.16 0.16 0.22 0.72 0.08 MHL 26.58 13.26 11.27 21.76 3.13 0.50 19.61 0.21 0.31 0.07 0.92 表 3 MHL分选组分的基本分析数据及其收率
Table 3 Analysis parameter and yield of MHL flotation fractions
Sample Proximate analysis w/% Ultimate analysis w/% MCI/% Yield/% Mad Ad Vdaf Cdaf Hdaf Ndaf Sd O* MHL-1.30 2.38 0.90 39.62 81.66 5.28 1.16 0.16 11.73 0.64 54.40 MHL-1.35 2.34 1.12 38.87 81.96 5.21 1.16 0.16 11.50 0.71 79.56 MHL-1.45 2.26 1.84 37.54 82.16 5.14 1.13 0.17 11.40 1.07 90.88 MHL-Raw 3.54 4.90 37.63 81.61 4.99 1.07 0.34 11.97 4.83 100.00 note: ad: air dried basis; d: dry basis; daf: dry and ash-free basis; *: by difference 表 4 MHL分选组分的煤岩分析
Table 4 Petrographic analysis of MHL flotation fractions
Sample Vitrinite
/%Liptinite
/%Inertinite
/%Mineral
/%Rmax MHL-1.30 83.81 0.45 15.59 0.15 0.53 MHL-1.35 73.76 0.30 25.64 0.30 0.60 MHL-1.45 65.31 0.27 33.74 0.68 0.56 MHL-Raw 60.34 0.26 38.11 1.29 0.51 note: Rmax: mean maximum vitrinite reflectance 表 5 MHL分选组分红外和拉曼结构参数
Table 5 Structural parameters of FT-IR and Raman spectra of MHL flotation fractions
Sample fa I1 I2 I(Gr+Vl+Vr)/ID MHL-1.30 0.71 0.48 1.67 4.07 MHL-1.35 0.72 0.52 1.57 3.37 MHL-1.45 0.73 0.53 1.32 3.28 MHL-Raw 0.74 0.54 1.19 2.50 表 6 MHL分选组分与LL配煤的基氏流动度参数
Table 6 Gieseler fluidity parameters of coal blends of MHL flotation fractions and LL coal
Sample t1/℃ t2/℃ t3/℃ Δt/℃ Fmax/(dd·min−1) LL 432.1 474.9 511.5 79.4 244.7 BC-coal-1.30 432.1 472.9 502.0 69.9 18.3 BC-coal-1.35 427.3 474.3 504.8 76.5 19.4 BC-coal-1.45 428.1 471.4 501.9 73.8 15.9 BC-coal-Raw 429.5 468.2 500.5 71.0 9.9 note: t1: softening temperature; t2: max fluidity temperature; t3: resolidification temperature; Δt: plastic range; Fmax: maximum fluidity 表 7 MHL不同分选组分与LL煤配煤焦的气孔结构参数
Table 7 Pore structure parameters of coal blend cokes from pyrolysis of LL coal and MHL flotation fractions
Sample BC-coke-
1.30BC-coke-
1.35BC-coke-
1.45BC-coke-
RawSBET/(m2·g−1) 4.26 6.82 4.95 3.16 rBJH/nm 5.47 4.81 5.52 6.76 vBJH/(mm3·g−1) 1.79 1.77 2.32 1.79 -
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