Title: X-ray photoelectron spectroscopy study on the chemical forms of S, C and O in coal before and after microwave desulphurisation

Authors: Yancheng Yang; Xiuxiang Tao; Huan He; Ning Xu; Longfei Tang; Shiwei Wang; Jifeng Guo; Liang Chen; Zhao Yang

Addresses: School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116 Jiangsu, China ' School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116 Jiangsu, China; Key Laboratory of Coal Processing and Efficient Utilisation, Ministry of Education, China University of Mining and Technology, No. 1 Daxue Rd. South Lake Campus of CUMT, C.P. 221116, Xuzhou, Jiangsu, China ' School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116 Jiangsu, China; Key Laboratory of Coal Processing and Efficient Utilisation, Ministry of Education, China University of Mining and Technology, No. 1 Daxue Rd. South Lake Campus of CUMT, C.P. 221116, Xuzhou, Jiangsu, China ' School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116 Jiangsu, China ' School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116 Jiangsu, China ' School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116 Jiangsu, China ' School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116 Jiangsu, China ' School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116 Jiangsu, China ' School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116 Jiangsu, China

Abstract: The chemical forms of S, C and O of high-sulphur bituminous coal were analysed before and after microwave desulphurisation by using X-ray photoelectron spectroscopy (XPS). Sulphur existed as 17.908% mercaptan (sulfoether) and 62.160% thiophene before microwave irradiation and decreased to 4.644% mercaptan (sulfoether) and 49.483% thiophene after irradiation with assistance of alkali solution. On the contrary, sulphur that occurred in the chemical form of sulfone (sulfoxide) and sulphates increased from 7.516% and 12.416% to 14.697% and 31.176%, respectively. This increase may be due to the mobility of sulphur-containing species and the oxidisation effect of desulphurisation additive. After irradiation, the relative contents of C-H and C-C groups decreased while C=O and COO-groups in the coal increased. This shows that the organic carbon is oxidised to a higher valence state. These observed changes in functionalities led to a low coking quality of the desulphurised coal. [Received: February 5, 2015; Accepted: December 12, 2015]

Keywords: microwave desulphurisation; high-sulphur coal; X-ray photoelectron spectroscopy; XPS; chemical form; coking quality; migration mechanism.

DOI: 10.1504/IJOGCT.2017.084444

International Journal of Oil, Gas and Coal Technology, 2017 Vol.15 No.3, pp.267 - 286

Received: 02 Mar 2015
Accepted: 12 Dec 2015
Published online: 07 Jun 2017 *

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