Effect of Solvent Treatment on the Composition and Structure of Santanghu Long Flame Coal and Its Rapid Pyrolysis Products

Jia Guo; Meixia Zhu; Wenlong Mo; Yanxiong Wang; Junrong Yuan; Ronglan Wu; Junmin Niu; Kongjun Ma; Wencang Guo; Xianyong Wei; Xing Fan; Naeem Akram

doi:10.3390/molecules28207074

Effect of Solvent Treatment on the Composition and Structure of Santanghu Long Flame Coal and Its Rapid Pyrolysis Products

Molecules. 2023 Oct 13;28(20):7074. doi: 10.3390/molecules28207074.

Authors

Jia Guo^{1

2}, Meixia Zhu², Wenlong Mo^{1

2}, Yanxiong Wang², Junrong Yuan², Ronglan Wu², Junmin Niu¹, Kongjun Ma², Wencang Guo¹, Xianyong Wei^{2

3}, Xing Fan², Naeem Akram⁴

Affiliations

¹ Xinjiang Energy Co., Ltd., Urumqi 830000, China.
² State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources and Key Laboratory of Coal Clean Conversion & Chemical Engineering Process (Xinjiang Uyghur Autonomous Region), School of Chemical Engineering and Technology, Xinjiang University, Urumqi 830046, China.
³ Key Laboratory of Coal Processing and Efficient Utilization, Ministry of Education, China University of Mining & Technology, Xuzhou 221116, China.
⁴ School of Chemical Engineering, Minhaj University Lahore, Lahore 54000, Pakistan.

Abstract

Easily soluble organic components in Santanghu long flame coal (SLFC) from Hami (Xinjiang, China) were separated by CS₂ and acetone mixed solvent (v/v = 1:1) under ultrasonic condition, and the extract residue was stratified by carbon tetrachloride to obtain the light raffinate component (SLFC-L). The effect of solvent treatment on the composition and structure of the coal and its rapid pyrolysis products was analyzed. Solvent treatment can reduce the moisture content in coal from 9.48% to 6.45% and increase the volatile matter from 26.59% to 28.78%, while the macromolecular structure of the coal changed slightly, demonstrating the stability of coal's complex organic structure. Compared with raw coal, the relative contents of oxygen-containing functional groups and aromatic groups in SLFC-L are higher, and the weight loss rates of both SLFC and SLFC-L reached the maximum at about 450 °C. In contrast, the loss rate of SLFC-L is more obvious, being 33.62% higher than that of SLFC. Pyrolysis products from SLFC at 450 °C by Py-GC/MS are mainly aliphatic hydrocarbons and oxygenated compounds, and the relative contents of aliphatic hydrocarbons decreased from 48.48% to 36.13%, while the contents of oxygenates increased from 39.07% to 44.95%. Overall, the composition and functional group in the coal sample were changed after solvent treatment, resulting in a difference in the composition and distribution of its pyrolysis products.

Keywords: Py-GC/MS; coal structure; products distribution; solvent treatment.

Grants and funding

This research was funded by the special project for regional collaborative innovation of Xinjiang Uyghur Autonomous Region (2022E01057), the National Natural Science Foundation of China (22068035), the science and technology project of Hami (hmkjjh202307) and the Scientific Research Program of Xinjiang Energy Co., Ltd. “Composition/structure characteristics and catalytic cracking of organic matter in the middle–low-rank coal in Xinjiang”, “Composition and structure analysis of low-middle rank coal in Xinjiang and its thermochemical transformation”, and “Testing, identification, and analysis of organic matter composition and structure in medium and low-rank coal”.