Investigation on the structural features of Hecaogou subbituminous coal and its residues by multiple technical strategies. (1st February 2022)

• Record Type: Journal Article
• Authors: Kang, Yu-Hong; Ma, Ze-Yu; Zhang, Xiao-Qi; Wei, Xian-Yong; Li, Yan-Jun; Liu, Guang-Hui; Wang, Ai-Min; Ma, Xiang-Rong; Yan, Long; Zong, Zhi-Min; Bai, Hong-Cun
• Is Part Of: Fuel. Volume 309(2022)
• Publication Date: 2022-02-01
• Subjects: Subbituminous coal -- Residues -- Molecular structure -- Non-destructive tools -- Flash pyrolysis; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2021.122111
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: Extraction and subsequent E can release many SSs from HSBC and IEP. The predominant CS in HSBC and its R s are aliphatic and aromatic carbons. The main oxygen occurrence are >C-OH and >C-O- moieties in HSBC and its R s. R S, especially RIEP, can be further used in pyrolysis or porous material precursors. Abstract: The structural features (SFs) of Hecaogou subbituminous coal (HSBC) and its residues ( R s) were investigated with non-destructive tools, including scanning electron microscope (SEM), solid-state 13 C nuclear magnetic resonance (SS 13 C NMR), Fourier transform infrared spectrometer (FTIRS), and X-ray photoelectron spectrometer (XRPES), combined with thermogravimetric analyzer (TGA) and flash pyrolysis (FP). SS 13 C NMR analysis shows that both HSBC and its R s consist of aliphatic, aromatic, and carbonyl carbon species. The total content of aliphatic carbon species in the R s is lower than that in HSBC, but the content of carbonyl carbon species is basically unchanged. In both HSBC and its R s, aliphatic linkages connect 3–5 aromatic rings (ARs) and the number of substituents on each AR is up to 2 on average. Based on the semi-quantitative analysis with FTIRS and TGA, cleavaging weak- and medium-strength covalent bonds (>Cal -X-, X denotes H, N, S, or >Cal ) should be the main reactions during the ethanolysis of HSBC and its inextractable portion. The analysis with XRPES indicates that the main oxygen-, nitrogen-, and sulfur-containing moieties are >C-O- groups, pyrrolic, and aromatic and sulfonic sulfurs, respectively, on the surface of HSBC and its R s. Considerable amounts of alkanes and alkenes were released and non-substituted arenes are the main arenes released from the FP of HSBC and its R s.