Influence of structural nonuniformity on features of thermal decomposition in coal

Authors: Ульянова Е. В., Малинникова О. Н., Пашичев Б. Н.

The structure of coal sampled from seams of the Kuznetsk Coal Basin and the features of thermal decomposition of coal substance in heating is studied. Thermal stability of components in the molecular structure of coal was analyzed based on the change in mass of a coal sample and the rate of this change versus temperature. The obtained dependences were compared with ignitability and outburst hazard of coal. With the help of digital images of scanning electron microscopy of surface of coal samples with thousand times magnification, the space complexity and information entropy are determined, and the statistics characteristics of the entropy–complexity values are calculated, which allows assessing spatial nonuniformity (orderliness) of structural elements in the test samples. Furthermore, it is shown that outburst-nonhazardous coal possesses a more ordered structure as against outburst-hazardous coal which, alongside with ordered regions, contains regions with more random structure of elements. It is also demonstrated that coal from selfignitable and outburst-hazardous seams have less ordered structure and features higher velocity of decomposition in pyrolysis without air access; moreover, self-ignitable coal looses mass at a rate two times higher than non-ignitable coal. In air the pyrolysis of coal with ordered structure runs at higher velocity. The conclusion is made that the thermal resistance of coal greatly depends on its structural orderliness.

Keywords: coal, thermo-gravimetric analysis, digital images of coal surface, information entropy, complexity, structural orderliness of elements, self-ignition, outburst hazard.
For citation:

Ulyanova E. V., Malinnikova O. N., Pashichev B. N. Influence of structural nonuniformity on features of thermal decomposition in coal. MIAB. Mining Inf. Anal. Bull. 2020;(2):71-81. [In Russ]. DOI: 10.25018/0236-1493-2020-2-0-71-81.

Acknowledgements:
Issue number: 2
Year: 2020
Page number: 71-81
ISBN: 0236-1493
UDK: 538.91:539.213.2
DOI: 10.25018/0236-1493-2020-2-0-71-81
Article receipt date: 09.07.2019
Date of review receipt: 09.12.2019
Date of the editorial board′s decision on the article′s publishing: 20.01.2020
About authors:

E.V. Ulyanova1, Dr. Sci. (Eng.), Leading Researcher, e-mail: ekaterina-ulyanova@yandex.ru,
O.N. Malinnikova1, Dr. Sci. (Eng.), Head of Laboratory, e-mail: olga_malinnikova@mail.ru,
B.N. Pashichev1, Graduate Student, Leading Engineer, e-mail: borisnik-pa@yandex.ru,
1 Institute of Problems of Comprehensive Exploitation of Mineral Resources of Russian Academy of Sciences, 111020, Moscow, Russia.

 

For contacts:

E.V. Ulyanova, e-mail: ekaterina-ulyanova@yandex.ru.

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