HAZRA , BODHISATWA and SINGH, DEEPENDRA PRATAP and CHAKRABORTY, PRASENJEET and DAS, HOMARGHA and SINGH, VIVEK and SAHU, SANTI GOPAL and SINGH, PRADEEP K (2022) Structural and thermal properties of vitrain lithotype in coal-inferences from TG-DTG-DSC, Rock-Eval and X-ray diAraction. Journal of Earth System Science, 131 (2). pp. 1-12. ISSN 0253-4126

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Abstract

Vitrain is one of the most important lithotype for the end utilization of humic coals in relevant industries. In this work, we examine the thermal, structural and pyrolysis properties of vitrains, manually isolated from coals of three distinct thermal maturity levels (rank). The high volatile bituminous (HvbA) vitrain showed highest moisture content and reactivity during combustion, while showing least Rock-Eval S2 Tmax and S4 Tpeak. On the other hand, the low volatile (Lvb) sample showed properties exact opposite to that of the HvbA sample. Thus, the rank of the vitrains was observed to directly control their behaviour. Owing to their inherently lower ash content, all the vitrains during thermogravimetric analysis developed smooth thermograms, indicating easy burning. Interlayer spacing (d002), obtained from XRD displayed a strong decrease with increasing coal rank, indicating formation of condensed stacking structures with increasing rank. On the other hand, other XRD parameters, viz., the crystallite height (Lc) and the crystallite diameter (La) were not correlated with the rank of the samples. Rock-Eval S2 pyrograms depicted distinctive responses for the vitrains. While smooth curves were observed for the HvbA vitrain, the pyrograms showed unevenness and spikes for the Mvb and Lvb vitrains. We interpret these spikes or ruggedness to be caused due to melt formation during pyrolysis of Lvb and Mvb vitrains, and concomitant gas/bubble-bursting. We back our results with distinctive observations from the Beld emission scanning electron microscope (FE-SEM) of the pyrolysis-residues of the vitrains. We interpret that the distinctive S2 signatures shown by coals can be useful in predicting their end usage

Item Type:	Article
Uncontrolled Keywords:	Vitrain Rock-Eval S2pyrograms crystallites thermogravimetry
Subjects:	Rock Testing
Divisions:	UNSPECIFIED
Depositing User:	Mr. B. R. Panduranga
Date Deposited:	26 Aug 2022 07:43
Last Modified:	26 Aug 2022 07:43
URI:	http://cimfr.csircentral.net/id/eprint/2522

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