Influence of composite chloride salt retardant on the characteristics of coal spontaneous combustion and comprehensive evaluation methodology

ABSTRACT

In this study, we aimed to improve the efficacy and longevity of single inhibitors. NaCl, CaCl₂, MgCl₂, and layered double hydroxides (LDHs) were selected as the inhibitory components for experimental study. The impact of the composite inhibitors on the spontaneous combustion characteristics of the coal was studied through temperature programmed experiment, thermal analysis experiments, thermogravimetric mass spectrometry and entropy weight method, and the optimal inhibitor was determined. The findings indicate that the apparent activation energy (E_a) of the coal sample, with the addition of inhibitors during the oxidation stage, was improved. E_a of MgCl₂ +1.0 LDHs + Coal was the highest (127.28 kJ/mol), i.e. 35.99 kJ/mol higher than that of the original coal. The inclusion of the inhibitor increased the characteristic ignition temperatures of the coal samples compared with the original coal. The highest ignition temperature was observed for MgCl₂ +0.5 LDHs + Coal, reaching (323.98°C), i.e. 11.42°C higher than that of the original coal. The addition of inhibitors significantly inhibited the production of CO. Among the three chloride salts, MgCl₂ exhibited the strongest inhibitory effect on CO production. According to the entropy weight method, MgCl₂ +0.5 LDHs showed the best inhibitory effect. The results show that the composite halogen inhibitor can effectively inhibit the spontaneous combustion of coal.

KEYWORDS:

• Coal spontaneous combustion
• chloride salts
• LDHs
• composite inhibitor
• characterization parameters
• entropy method

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Data Availability Statement

Data will be made available on request.

CRediT authorship contribution statement

Lingjie Zhu: Methodology, Data curation, Writing – original draft. Xiaomeng Xu: Conceptualization, Methodology, Writing – review & editing, Supervision. Wanli Liu: Investigation, Writing – review & editing, Supervision. Wenwen Zhao: Conceptualization, Formal Analysis, Methodology. Jiang Lu: Data curation, Formal Analysis, Methodology. Jingwen Yan: Data curation, Investigation.

Additional information

Funding

This work was supported by the Fundamental Research Funds for Cultivation of Young Sci-tech Talents, China Jiliang University [Project Category A, 2022YW06] and Natural Science Foundation of Zhejiang Province [LY23E040001].