Physicochemical properties, combustion kinetics and thermodynamics of oxidized lignite

Mingqiang Gao, Cheng Cheng, Zhenyong Miao, Keji Wan and Qiongqiong He

Energy, 2023, vol. 268, issue C

Abstract: Lignite oxidizes easily during storage and transportation. Furthermore, the surface characteristics of lignite change during oxidation, affecting its thermal conversion process. Herein, the surface functional groups and pore structures of lignite oxidized at temperatures below 190 °C were investigated. Moreover, the kinetics and thermodynamics of the combustion of lignite were analyzed using thermogravimetric analysis. The relationship between the surface structure and combustion performance of oxidized lignite was established, and the effect of oxidation on the characteristics of the combustion process was evaluated. The results revealed that the value of CH3/CH2 increased considerably upon increasing oxidation temperature from 70 to 150 °C. The number of –OH groups decreased with increasing in oxidation temperature, whereas the number of CO groups decreased gradually, then increased significantly, and lastly decreased with increasing oxidation temperature. The mesoporous structure of lignite was severely damaged during oxidation, the specific surface area and pore volume of oxidized lignite were lower than those of raw coal, and the average pore diameter of oxidized lignite was significantly higher than that of raw lignite. The poor combustion performance of oxidized lignite was attributed to its low mesopore specific surface area and low pore volume. The activation energy (Ea) of lignite during combustion was calculated to be 35.29 kJ/mol using the Ginstling-Broushtein equation, and the Ea of oxidized lignite ranged between 40.53 and 45.93 kJ/mol. These results indicate that a large amount of energy was required to burn oxidized lignite. Therefore, the oxidation of lignite should be avoided during the storage process to damage the pore structure, thus affecting the combustion performance; the pore structure of oxidized lignite can be adjusted to enhance its combustion performance. This will effectively improve the utilization efficiency and economic value of lignite.

Keywords: Activation energy; Combustion; Kinetics and thermodynamics; Oxidized lignite; Pore structure (search for similar items in EconPapers)
Date: 2023
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (4)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0360544223000518
Full text for ScienceDirect subscribers only

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:eee:energy:v:268:y:2023:i:c:s0360544223000518

DOI: 10.1016/j.energy.2023.126657

Access Statistics for this article

Energy is currently edited by Henrik Lund and Mark J. Kaiser

More articles in Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().