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Study on the Change of Dielectric Properties and Chemical-Mechanism during Coal Low-Temperature Oxidation

The study aims to investigate the variation of the coal dielectric properties during coal low-temperature oxidation and the effect of oxidation product on the coal dielectric properties. Four different types of coal were prepared under low-temperature oxidation condition, and the coal dielectric pro...

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Autores principales: Zhu, Hongqing, Wang, Haoran, Wang, Wei, Liu, Jiuli
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7069977/
https://www.ncbi.nlm.nih.gov/pubmed/32170158
http://dx.doi.org/10.1038/s41598-020-61584-0
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author Zhu, Hongqing
Wang, Haoran
Wang, Wei
Liu, Jiuli
author_facet Zhu, Hongqing
Wang, Haoran
Wang, Wei
Liu, Jiuli
author_sort Zhu, Hongqing
collection PubMed
description The study aims to investigate the variation of the coal dielectric properties during coal low-temperature oxidation and the effect of oxidation product on the coal dielectric properties. Four different types of coal were prepared under low-temperature oxidation condition, and the coal dielectric properties were measured with an impedance analyzer at frequencies ranging between 20 Hz and 30 MHz. The oxygen-containing functional groups in oxidized coal samples were semi-quantitatively evaluated using Fourier transform infrared spectroscopy. Low-temperature oxidation stage of coal spontaneous combustion could be predicted according to the change of coal dielectric properties in the process of temperature rise. It was found that the dielectric constant of coal with high water content decreased exponentially with temperature. For coal sample with low water content, the dielectric properties changed piecewise linearly with temperature. Coal dehydration was considered to be the reason for the decrease of the dielectric constant from 30 °C to 120 °C. The increase of the relative content of oxygen-containing functional groups, especially carbonyl compounds, could be the reason for the rise of the coal dielectric constant from T(2) to T(3).
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spelling pubmed-70699772020-03-22 Study on the Change of Dielectric Properties and Chemical-Mechanism during Coal Low-Temperature Oxidation Zhu, Hongqing Wang, Haoran Wang, Wei Liu, Jiuli Sci Rep Article The study aims to investigate the variation of the coal dielectric properties during coal low-temperature oxidation and the effect of oxidation product on the coal dielectric properties. Four different types of coal were prepared under low-temperature oxidation condition, and the coal dielectric properties were measured with an impedance analyzer at frequencies ranging between 20 Hz and 30 MHz. The oxygen-containing functional groups in oxidized coal samples were semi-quantitatively evaluated using Fourier transform infrared spectroscopy. Low-temperature oxidation stage of coal spontaneous combustion could be predicted according to the change of coal dielectric properties in the process of temperature rise. It was found that the dielectric constant of coal with high water content decreased exponentially with temperature. For coal sample with low water content, the dielectric properties changed piecewise linearly with temperature. Coal dehydration was considered to be the reason for the decrease of the dielectric constant from 30 °C to 120 °C. The increase of the relative content of oxygen-containing functional groups, especially carbonyl compounds, could be the reason for the rise of the coal dielectric constant from T(2) to T(3). Nature Publishing Group UK 2020-03-13 /pmc/articles/PMC7069977/ /pubmed/32170158 http://dx.doi.org/10.1038/s41598-020-61584-0 Text en © The Author(s) 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Zhu, Hongqing
Wang, Haoran
Wang, Wei
Liu, Jiuli
Study on the Change of Dielectric Properties and Chemical-Mechanism during Coal Low-Temperature Oxidation
title Study on the Change of Dielectric Properties and Chemical-Mechanism during Coal Low-Temperature Oxidation
title_full Study on the Change of Dielectric Properties and Chemical-Mechanism during Coal Low-Temperature Oxidation
title_fullStr Study on the Change of Dielectric Properties and Chemical-Mechanism during Coal Low-Temperature Oxidation
title_full_unstemmed Study on the Change of Dielectric Properties and Chemical-Mechanism during Coal Low-Temperature Oxidation
title_short Study on the Change of Dielectric Properties and Chemical-Mechanism during Coal Low-Temperature Oxidation
title_sort study on the change of dielectric properties and chemical-mechanism during coal low-temperature oxidation
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7069977/
https://www.ncbi.nlm.nih.gov/pubmed/32170158
http://dx.doi.org/10.1038/s41598-020-61584-0
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