Structural difference of gas coal separation components and its effect on sulfur transformation during pyrolysis of high sulfur coal
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摘要: 利用ZnCl2溶液将两种气煤分别分选为不同镜质组含量的四种组分，通过核磁共振波谱(13C NMR)、煤岩分析仪、X射线荧光光谱(XRF)和基氏流动仪等表征分析了分选组分的炭结构、显微岩相组成、灰成分和胶质体行为，结合X射线光电子能谱仪(XPS)探讨了不同气煤分选组分对高硫煤硫分热变迁行为及焦炭中形态硫分布的影响。结果表明，随着气煤中镜质组含量的增加，脂肪碳比例增大，热解过程中挥发分释放量增多，其中的氢自由基促进了形态硫的分解且及时稳定生成的硫自由基，形成含硫气体释放，使焦中硫含量降低；气煤中低密度组分的最大流动度最大、塑性区间最宽，与高硫煤共热解过程中胶质体稳定性最好；气煤中碱性矿物质主要富集在高密度组分中，导致共热解焦中硫化物硫和硫酸盐硫增加；共热解过程中，富集气煤中镜质组和选用碱性矿物质易脱除的煤种有利于焦中硫分的降低。Abstract: Two gas coals were respectively separated into four components with different vitrinite content using ZnCl2 solution. The carbon structure, composition of coal macerals and minerals, and plastic layer behavior of separating components were characterized by nuclear magnetic resonance spectrometer (13C NMR), coal rock analyzer, X-ray fluorescence spectrometry (XRF) and Gieseler fluidity. Combining with X-ray photoelectron spectroscopy (XPS), effect of different gas coal separation components on sulfur transformation behavior during pyrolysis of high-sulfur coal and distribution of sulfur forms in coke was investigated. The results show that with increase of vitrinite content in gas coal, the relative ratio of aliphatic carbon in coal increases, and the release amount of volatiles increases during pyrolysis; hydrogen free radicals in volatiles promote decomposition of sulfur, stabilize sulfur free radicals in time and release as sulfur-containing gases, and thus sulfur content in coke is reduced. Low density components in gas coal have the largest maximum fluidity and widest plastic range, and stability of plastic layer is the best during co-pyrolysis with high sulfur coal. The basic minerals in gas coal are mainly enriched in high density components, which leads to increase of sulfide sulfur and sulfate sulfur in the coke. For utilization of gas coal in coal-blending pyrolysis, enrichment of vitrinite and selection of coals with easier removal of alkaline minerals are beneficial for reducing sulfur in coke.
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Key words:
- gas coal /
- separation /
- high sulfur coal /
- sulfur transformation /
- plastic layer /
- alkaline minerals
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图 2 LL+HCG-D1焦样的XPS光谱分峰拟合图
Figure 2 XPS spectrum peak fitting diagram of LL+HCG-D1 coke
图 3 气煤分选组分的TG及DTG曲线
Figure 3 TG and DTG curves of gas coal and its separation components
图 4 不同配煤方案焦中硫含量和脱硫率
Figure 4 Sulfur content in coke and sulfur removal rate from different coal blending schemes
图 6 不同配煤焦中硫含量和热解脱硫率实验值与计算值的差值
Figure 6 DSD and SD from different coal blending schemes
表 1 煤样的工业分析、元素分析和形态硫分析
Table 1 Proximate, ultimate, and sulfur form analyses of coal samples
Sample Proximate analysis w/% Ultimate analysis w/% Sulfur form wd/% Mad Ad Vdaf Cdaf Hdaf Ndaf St,d O* Ss Sp So HCG-R 1.55 8.88 40.52 83.98 5.70 2.05 0.52 7.70 0.01 0.14 0.37 LN-R 1.40 6.10 37.63 84.96 5.44 1.13 0.52 7.91 0.01 0.28 0.23 LL 0.20 9.94 19.90 88.49 4.69 1.42 1.94 3.25 0.02 0.26 1.66 note: ad: air dried basis; d: dry basis; daf: dry and ash-free basis; St: total sulfur; Ss: sulfate sulfur; Sp: pyritic sulfur; So: organic sulfur; O*: by difference 
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表 2 气煤分选组分的工业分析和元素分析
Table 2 Proximate and ultimate analyses of separation fractions from the two gas coals
Sample Proximate analysis w/% Ultimate analysis w/% Mad Ad Vdaf Cdaf Hdaf Ndaf St,d O* HCG-D1 1.44 3.46 44.37 83.93 5.76 2.09 0.49 7.71 HCG -D2 1.47 8.85 37.29 84.19 5.56 1.96 0.48 7.76 HCG -D3 1.43 14.97 34.12 84.08 5.49 1.92 0.48 7.95 HCG -D4 1.29 23.84 31.57 82.88 5.55 1.88 0.50 9.03 LN-D1 1.20 3.14 39.47 84.65 5.57 1.15 0.29 8.33 LN-D2 1.24 5.64 33.66 85.35 5.15 1.08 0.38 8.01 LN-D3 1.20 9.62 31.86 84.63 5.04 1.08 0.57 8.61 LN-D4 1.14 17.48 30.41 83.51 4.95 1.05 0.92 9.37 note: ad: air dried basis; d: dry basis; daf: dry and ash-free basis; O*: by difference; St: total sulfur
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表 3 13C NMR中不同类性质碳对应的化学位移
Table 3 Chemical shifts corresponding to different types of carbons in 13C NMR
Chemical shift δ Carbon type Carbon structure Symbol 14−22 aliphatic methyl 
fala 22−26 aromatic methyl −CH2−CH2−CH3 fal1 26−37 methylene −CH2−CH2−CH2− fal2 37−50 quaternary sp3 C 
fal3 50−95 oxygen aliphatic carbon −CH2−O−, −CH−O− falO 95−129 protonated aromatic carbon 
faH 129−137 aromatic bridgehead carbon 
faB 137−149 aliphatic substituted aromatic carbon 
faS 149−164 oxygen aromatic carbon 
faO 164−190 carboxyl −COOH/R faC1 190−220 quinone and carbonyl carbon 
faC2
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表 4 不同煤样的灰成分分析
Table 4 Ash composition analyses of different coal samples
Sample Ash composition w/% MCI/% SiO2 Al2O3 Fe2O3 CaO MgO SO3 TiO2 K2O Na2O P2O5 HCG-R 56.98 26.61 5.50 3.23 1.42 1.48 1.10 1.08 0.77 0.22 0.03 HCG-D1 53.05 23.88 7.25 4.91 1.92 2.31 1.79 1.00 0.78 0.50 0.02 HCG-D2 58.68 25.55 5.61 2.14 1.47 1.02 1.17 1.11 0.59 0.26 0.03 HCG-D3 61.13 25.98 4.24 1.59 1.19 0.98 0.96 1.05 0.57 0.15 0.03 HCG-D4 61.17 28.20 3.38 1.23 0.95 0.87 0.83 1.09 0.44 0.12 0.04 LN-R 37.82 20.60 14.48 11.92 3.43 5.95 0.75 0.27 0.78 0.04 0.08 LN-D1 34.48 23.14 10.97 11.63 4.33 10.06 0.94 0.19 1.06 0.05 0.04 LN-D2 43.50 25.92 9.93 6.60 2.42 6.62 0.73 0.30 1.29 0.03 0.04 LN-D3 43.93 24.79 10.23 7.58 2.50 7.02 0.64 0.30 1.08 0.02 0.07 LN-D4 43.04 21.45 11.56 11.12 3.38 5.91 0.66 0.28 0.73 0.03 0.15
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表 5 气煤及其分选组分的煤岩分析和黏结指数
Table 5 Maceral analysis and caking index of gas coal and its separation components
Sample Maceral group/% Rmax/% G V I E M HCG-R 76.35 19.05 0.51 4.09 0.83 67.75 HCG-D1 86.96 10.70 0.49 1.85 0.80 83.14 HCG-D2 64.05 29.17 0.27 6.51 0.82 30.91 HCG-D3 53.09 33.72 0.17 13.02 0.82 18.24 HCG-D4 43.70 37.53 0.13 18.64 0.78 17.37 LN-R 61.22 34.65 0.83 3.30 0.71 46.88 LN-D1 69.37 29.09 0.84 0.70 0.71 66.29 LN-D2 45.51 51.72 0.26 2.51 0.76 17.47 LN-D3 41.33 55.73 0.40 2.54 0.79 15.95 LN-D4 39.02 56.78 0.27 3.93 0.82 15.14 note: V: vitrinite, I: inertinite, E: exinite, M is minerals, Rmax: average maximum vitrinite reflectance, G: caking index
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表 6 气煤及分选组分的焦产率和脱硫率
Table 6 Coke yield and sulfur removal rate of gas coal and separation components
Sample Coke yield/% Sulfur content in coke/% Total sulfur removal/% HCG-R 64.07 0.46 42.43 HCG-D1 61.58 0.41 47.72 HCG-D2 64.84 0.40 45.16 HCG-D3 67.37 0.37 47.31 HCG-D4 69.89 0.43 39.12 LN-R 64.95 0.53 32.90 LN-D1 63.10 0.38 17.03 LN-D2 67.98 0.42 23.66 LN-D3 69.89 0.51 37.14 LN-D4 71.11 0.99 22.30
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表 7 不同煤样 13C NMR波谱图拟合结果
Table 7 Fitting results of 13C NMR spectra of different coal samples
Carbon type/% HCG-R HCG-D1 HCG-D2 HCG-D3 HCG-D4 LN-R LN-D1 LN-D2 LN-D3 LN-D4 fala 5.89 8.01 7.31 4.30 5.10 6.50 5.99 4.70 5.28 6.35 fal1 8.91 9.16 4.98 9.33 6.46 5.25 6.76 4.95 4.64 2.44 fal2 8.36 7.18 13.20 10.00 11.93 10.14 9.25 10.65 8.69 11.89 fal3 14.63 14.42 12.16 11.48 13.05 11.91 12.72 10.56 11.19 8.86 falO 7.21 7.18 7.10 8.90 6.54 7.62 7.46 8.11 8.53 8.10 faH 4.86 4.64 4.92 8.47 4.58 5.52 5.72 5.74 5.44 6.40 fa B 25.24 25.04 25.54 22.65 26.90 26.66 26.64 28.94 30.13 29.88 faS 9.68 9.39 9.64 9.97 9.57 10.01 9.53 9.94 9.47 9.56 faO 4.61 4.51 4.57 4.40 4.54 4.89 4.66 4.35 4.31 4.16 faC1 7.58 7.52 7.69 7.37 8.19 8.28 8.16 9.17 9.49 9.31 faC2 3.03 2.93 2.90 3.13 3.14 3.22 3.10 2.89 2.83 3.06 fal 44.99 45.96 44.75 44.02 43.09 41.42 42.19 38.97 38.34 37.64 fa 44.40 43.59 44.66 45.48 45.59 47.08 46.55 48.97 49.34 49.99 farN 39.53 38.94 39.75 37.01 41.00 41.56 40.84 43.23 43.91 43.59
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表 8 不同单种煤的基氏流动度参数
Table 8 Gieseler fluidity parameters of different coal samples
Sample t1/℃ t2/℃ t3/℃ △t Fmax / (cm3·min−1) Area LL 419.6 473.1 509.6 90.0 302.9 7722.54 HCG-R 394.0 435.8 469.6 75.6 575.3 9757.81 HCG-D1 390.8 428.5 486.7 95.9 59984.8 602428.14 HCG-D2 400.9 443.8 474.9 74.0 211.8 3570.21 HCG-D3 401.9 438.5 470.6 68.7 78.6 1446.70 HCG-D4 408.4 438.8 467.9 59.5 39.5 619.91 LN-R 401.4 434.4 469.6 68.2 43.3 772.88 LN-D1 399.7 437.2 473.2 73.5 68.7 1244.43 LN-D2 407.0 431.3 464.8 57.8 9.5 223.87 LN-D3 415.9 432.6 462.4 46.5 3.9 97.75 LN-D4 418.6 432.5 462.5 43.9 2.7 67.17 note: t1: softening temperature, t2: maximum fluidity temperature, t3: resolidification temperature, △t: plastic range, Fmax: maximum fluidity
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表 9 不同配合煤的基氏流动度参数
Table 9 Gieseler fluidity parameters of different coal blends
Sample t1/℃ t2/℃ t3/℃ △t Fmax / ( cm3·min−1) Area HCG-R+LL 407.3 455.2 500.3 93.0 125.2 3132.27 HCG-D1+LL 406.2 451.6 497.7 91.5 181.0 4733.20 HCG-D2+LL 410.3 457.4 500.9 90.6 79.1 2250.22 HCG-D3+LL 415.3 462.3 503.2 87.9 64.0 1915.75 HCG-D4+LL 413.0 465.1 505.3 92.3 95.1 2721.85 LN-R+LL 413.4 460.6 503.9 90.5 26.1 878.86 LN-D1+LL 412.2 455.5 499.8 87.6 30.2 916.18 LN-D2+LL 413.4 459.8 500.4 87.0 19.2 726.01 LN-D3+LL 415.9 462.5 503.7 87.8 18.5 627.16 LN-D4+LL 417.5 470.0 503.3 85.8 26.4 798.26 note: t1: softening temperature, t2: maximum fluidity temperature, t3: resolidification temperature, △t: plastic range, Fmax: maximum fluidity
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