Differences in molecular composition of soluble organic species in two Chinese sub-bituminous coals with different reducibility
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摘要: 本研究首先利用等体积二硫化碳/丙酮溶剂对弱还原性淖毛湖次烟煤(NS)和强还原性不连沟次烟煤(BS)进行萃取得到萃取物和萃余物(ERs),再利用环己烷和甲醇对ERs进行连续热溶得到热溶物(SPs)。NS和BS的萃取物产率分别为10.6%和8.0%,在300℃下NS和BS热溶物的总收率分别为36.3%和11.5%,这说明NS中存在更多可溶有机质。NS和BS萃取物中化合物均以芳烃为主。与BS相比,NS热溶物中脂肪烃和酚类的相对含量明显较高,萃取物中化合物的相对分子量分布范围较宽,而热溶物中化合物的相对分子量分布范围较窄。Abstract: Naomaohu sub-bituminous (NS) with weak reducibility and Buliangou sub-bituminous (BS) with strong reducibility were extracted in isometric carbon disulfide/acetone mixed solvent to get extracts and extraction residues (ERs). The ERs were thermal dissolved in cyclohexane and methanol to get soluble portions (SPs). The yields of the extracts from NS (ENS) and BS (EBS) are 10.6% and 8.0%, respectively, and the total yields of the SPs from NS and BS at 300℃ are 36.3% and 11.5%, respectively, indicating the solubility of the organic species in NS are better than that in BS. Arenes are the dominated compounds both in ENS and EBS. The relative contents of aliphatic hydrocarbons and phenols in the SPs of NS are obvious higher than those of BS. The molecular weight distribution of the compounds in ENS is wider than that in EBS, while the molecular weight distribution of the compounds in the SPs from NS is narrower than that from BS.
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Key words:
- sub-bituminous coals /
- soluble organic species /
- molecular composition /
- thermal dissolution
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Table 1 Proximate and ultimate analyses of coal samples
Sample Proximate analysis w/% ultimate analysis wdaf/% GR, I Rmaxo/% Qgr, maf/(MJ·kg-1) Mad Ad Vdaf C H N S O* NS 6.36 5.37 44.21 68.51 3.66 1.08 0.57 26.18 0 0.36 25.59 BS 2.01 17.66 35.95 77.50 4.62 1.27 0.84 15.77 0 0.79 23.32 Mad: moisture (air dried base); Ad: ash (dry base, i.e., moisture-free base); Vdaf: volatile matter (dry and ash-free base); *: by difference; GR, I: caking index; Rmaxo: average vitrinite reflectance; Qgr, maf: gross calorific value (moist ash-free base) Wavenumber σ/cm-1 Assignment 3415 phenolic-OH groups stretching vibration 2925 asymmetric stretching vibration of aliphatic C-H 2852 symmetric stretching vibration of aliphatic C-H 1612 stretching vibration of aromatic nucleus C=C 1454 asymmetric bending vibration of aliphatic C-H 1373 symmetric bending vibration of aliphatic C-H 1213 asymmetric stretching vibration of C-O 1082 symmetric stretching vibration of C-O 815, 752 out-of-plane deformation vibration of aromatic C-H Table 3 Arenes identified by GC/MS in CSPs and MSPs
Compound RC/% CSPNS, 300 CSPBS, 300 MSPNS, 300 MSPBS, 300 Toluene 2.27 21.06 Ethyl-benzene 1.70 12.71 2.94 4.77 m-xylene 5.44 27.46 4.44 2.35 Isopropyl-benzene 0.87 0.48 1.34 Propyl-benzene 0.43 Ethylmethylbenzene 1.90 0.26 3.01 2.69 1, 2, 3-trimethyl-benzene 0.46 2.53 7.77 1.71 Indan 1.12 Butyl-benzene 0.18 0.22 1-ethyl-2, 3-dimethyl-benzene 1.01 2.48 But-2-enyl-benzene 0.6 But-1-enyl-benzene 0.57 2.97 (2-methyl-propenyl)-benzene 0.78 1, 2, 4, 5-tetramethyl-benzene 0.09 0.15 (1-methyl-allyl)-benzene 0.12 2.97 1.38 3-methyl-1H-indene 0.28 Azulene 0.26 (1-methyl-but-1-enyl)-benzene 0.25 Naphthalene 0.48 1.31 Cyclopentyl-benzene 0.10 2, 3-dimethyl-1H-indene 1.49 Methylnaphthalene 0.88 1.84 2.96 1, 8-dimethyl-1, 2, 3, 4-tetrahydro-naphthalene 0.39 Heptyl-benzene 0.44 1, 2, 3-trimethyl-1H-indene 0.23 1-ethyl-naphthalene 0.09 2, 6-dimethyl-naphthalene 1.07 1.49 2.81 1.61 Diphenylmethane 0.14 Octyl-benzene 0.80 1, 1, 4, 5, 6-pentamethyl-indan 0.58 Nonyl-benzene 0.29 9H-fluorene 0.86 2-methyl-9H-fluorene 0.17 0.65 3-methyl-biphenyl 0.22 7-isopropyl-1-methyl-naphthalene 0.17 Decyl-benzene 0.15 4-isopropyl-1, 6-dimethyl-naphthalene 0.16 0.11 1, 4, 5, 8-tetramethyl-naphthalene 0.4 Phenanthrene 0.15 9-methylene-9H-fluorene 0.15 1-methyl-anthracene 0.40 2-methyl-phenanthrene 0.25 Total 23.93 52.36 29.39 41.18 -
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