Effects of Vitrinite in Low-Rank Coal on the Structure and Combustion Reactivity of Pyrolysis Chars

Yanmei Xu; Qingyun Fu; Yingmin Hong; Ying Zhang; Liang Wang; Ke Bei; I-Ming Chou; Haoquan Hu; Zhiyan Pan

doi:10.1021/acsomega.0c01542

Effects of Vitrinite in Low-Rank Coal on the Structure and Combustion Reactivity of Pyrolysis Chars

ACS Omega. 2020 Jul 8;5(28):17314-17323. doi: 10.1021/acsomega.0c01542. eCollection 2020 Jul 21.

Authors

Yanmei Xu¹, Qingyun Fu¹, Yingmin Hong¹, Ying Zhang¹, Liang Wang¹, Ke Bei¹, I-Ming Chou², Haoquan Hu³, Zhiyan Pan¹

Affiliations

¹ College of Environment, Zhejiang University of Technology, Hangzhou, Zhejiang 310032, China.
² CAS Key Laboratory of Experimental Study Under Deep-sea Extreme Conditions, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan 572000, China.
³ State Key Laboratory of Fine Chemistry, Institute of Coal Chemical Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.

Abstract

Pyrolysis is a highly promising technology for the efficient utilization of low-rank coal. The structure of coal plays an important role in its utilization. In this paper, the evolution of the char structure during heat treatment (200-800 °C) of Naomaohu coal and its different vitrinite-rich fractions was studied. The functional group structure, aromatic ring structure, and crystallite size of chars were determined by Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and X-ray diffraction (XRD) spectroscopy, respectively. The results indicated that minerals inhibit the condensation reaction of aromatic rings during pyrolysis. The high vitrinite content in coal is conducive to the formation of larger char crystallite average sizes (L _a). The relationship between L _a (1.69-3.10 nm) and the Raman band area ratio A _{(G_R+V_L+V_R)}/A _D or A _D/A _all was established. In addition, the combustion performance and kinetics of chars were also investigated. The results showed that the char from high contents of the liptinite fraction has lower combustion reactivity, and demineralization treatment has significantly reduced the combustion reactivity of char.