He Li,Shisheng Liang,Yucui Hou,Yupeng Wang,Shuhang Ren,Weize Wu
Direct coal liquefaction (DCL) is not only for fuel but also for chemicals, which shows high efficiencies in atom utilization and energy. The study on coal structure is important to select coal for direct liquefaction . Naomaohu coal is a kind of subbituminous coal and a typical coal for direct liquefaction . In this work, the structure of Naomaohu coal was investigated via alkali‑oxygen oxidation , ruthenium ion catalyzed oxidation and physical analyses and a representative structural model with a model size of 128,755 amu was constructed. The structural characteristics show that the ratio of single-, double-, triple-, and quadruple-aromatic rings is 149:164:102:63. The triple- and quadruple-rings aromatic structures are mainly connected by C C bonds of 2–4 carbon atoms. The single- or double-ring is connected on the triple- and quadruple-rings aromatic structures through ether or ester bonds , which can be broken easily under mild conditions. Long alkyl side chains with carbon atoms from 13 to 25 accounting for 0.91 wt%. The high H/C, high oxygen content (mainly weak bonds such as ether and ester bonds between aromatic clusters), abundant single-, double-, triple, and quadruple-aromatic rings, and alkyl bridge bonds of 2–4 carbon atoms are beneficial to the mild liquefaction of Naomaohu coal
Lulu Yan,Yahe Zhang,Hongyu Yan,Yu Fan,Xuxia Liu,Chao Ma,Quan Shi
A lignite was subjected to sequential solvent extraction via continuously reducing particle size from around 20 to more than 200 mesh. Five sets of n-hexane and methanol extracts from the particles were characterized by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) and gas chromatography–mass spectrometry. The total extract yield for lignite when using hexane and methanol as solvents could reach to 0.98 and 15.12%, respectively. The results showed that more molecules with a similar structure but different composition could be extracted by continuously reducing the particle size of the residues, indicating the nonuniform distribution of the low-solubility molecules trapped in the coal particles. The extracts were abundant in branched long-chain aliphatic moieties and oxygen-containing compounds. With the increasing of the extraction degree, the content of alkanes in the extracts decreased rapidly. On the contrary, the content of the compounds with higher condensation and more oxygen atoms increased. It should be noted that polycyclic aromatic hydrocarbons were almost steadily present in all the extraction steps. The molecular composition and distribution of organic molecules in the lignite provide clues to the understanding of coal structure, which is significant for the environmental emission and development of processing techniques for the clean and high value-added utilizations of such a low-rank and abundant coal resource.
危险品化学品经营许可证（带存储）