The Temperature Field Evolution and Water Migration Law of Coal under Low-Temperature Freezing Conditions

Bo Li, Li Li, Laisheng Huang and Xiaoquan Lv
Additional contact information
Bo Li: School of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China
Li Li: School of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China
Laisheng Huang: School of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China
Xiaoquan Lv: School of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China

IJERPH, 2021, vol. 18, issue 24, 1-17

Abstract: This study examines the evolution law of the coal temperature field under low-temperature freezing conditions. The temperature inside coal samples with different water contents was measured in real-time at several measurement points in different locations inside the sample under the condition of low-temperature medium (liquid nitrogen) freezing. The temperature change curve was then used to analyse the laws of temperature propagation and the movement of the freezing front of the coal, which revealed the mechanism of internal water migration in the coal under low-temperature freezing conditions. The results indicate that the greater the water content of the coal sample, the greater the temperature propagation rate. The reasons for this are the phase change of ice and water inside the coal during the freezing process; the increase in the contact area of the ice and coal matrix caused by the volume expansion; and the joint action of the two. The process of the movement of the freezing front is due to the greater adsorption force of the ice lens than that of the coal matrix. Thus, the water molecules adsorbed in the unfrozen area of the coal matrix migrate towards the freezing front and form a new ice lens. Considering the temperature gradient and water content of the coal samples, Darcy’s permeation equation and water migration equation for the inside of the coal under freezing conditions were derived, and the segregation potential and matrix potential were analysed. The obtained theoretical and experimental results were found to be consistent. The higher the water content of the coal samples, the smaller the matrix potential for the hindrance of water migration. Furthermore, the larger the temperature gradient, the larger the segregation potential, and the faster the water migration rate.

Keywords: low-temperature freezing; temperature propagation; freezing front; water migration; coal (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2021
References: View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.mdpi.com/1660-4601/18/24/13188/pdf (application/pdf)
https://www.mdpi.com/1660-4601/18/24/13188/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jijerp:v:18:y:2021:i:24:p:13188-:d:702353

Access Statistics for this article

IJERPH is currently edited by Ms. Jenna Liu

More articles in IJERPH from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().