The influence mechanism of thermal invasion on spontaneous combustion of different coals using continuous adiabatic heating and non-isothermal oxidation method

IF 6.4 2区工程技术 Q1 THERMODYNAMICS

Case Studies in Thermal Engineering Pub Date : 2024-11-26 DOI:10.1016/j.csite.2024.105565

Xincheng Hu, Jiawen Cai, Yunquan Yao, Zhaoyang Yu, Jianguo Liu, Shanyang Wei, Zongqing Tang, Shengqiang Yang

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引用次数: 0

Abstract

Within deep coal mines, the elevated ground temperature has the potential to induce thermal invasion, thereby exacerbating coal spontaneous combustion (CSC). To investigate the influence mechanism of thermal invasion on CSC, experiments were conducted using coals of different metamorphic degrees (lignite, bitumite, and anthracite) with a continuous adiabatic heating and non-isothermal oxidation method in an oxidation furnace and an in-situ ESR spectrometer. Thermal invasion markedly enhanced the inherent susceptibility of spontaneous combustion of coals by increasing the oxygen consumption rate and lowering the apparent activation energy. This enhancement results from active free radicals generated during thermal invasion which accelerated coal-oxygen reactions during non-isothermal oxidation. These free radicals were found to be mainly carbon-centred radicals adjacent to an oxygen atom (alkyl radicals). An increase in both the g-factor value and free radical concentration was observed with thermal invasion temperature and invasion duration, especially in lignite, leading to a surge of free radical concentration during non-isothermal oxidation. The active free radicals generated during thermal invasion can easily react with oxygen, providing heat for coal-oxygen reactions and enabling rapid free radical generation. These findings offer insights for developing CSC evaluation and prevention strategies in deep mines where high ground temperatures are encountered.

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采用连续绝热加热和非等温氧化法研究了热侵入对不同煤自燃的影响机理

在深部煤矿中，地温升高有可能诱发热侵，从而加剧煤炭自燃。为了研究热侵入对CSC的影响机理，利用褐煤、烟煤和无烟煤等不同变质程度的煤，在氧化炉和原位ESR光谱仪上采用连续绝热加热和非等温氧化的方法进行了实验。热侵提高了煤的耗氧速率，降低了表观活化能，显著增强了煤的自燃固有易感性。这种增强是由于热侵入过程中产生的活性自由基加速了非等温氧化过程中的煤氧反应。这些自由基被发现主要是与氧原子相邻的碳中心自由基（烷基自由基）。g因子值和自由基浓度随热侵入温度和侵入时间的增加而增加，特别是在褐煤中，导致自由基浓度在非等温氧化过程中激增。热侵入过程中产生的活性自由基容易与氧反应，为煤氧反应提供热量，使自由基生成迅速。这些研究结果为在深部高温矿井中制定CSC评估和预防策略提供了见解。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Case Studies in Thermal Engineering Chemical Engineering-Fluid Flow and Transfer Processes

CiteScore

8.60

自引率

11.80%

发文量

812

审稿时长

76 days

期刊介绍： Case Studies in Thermal Engineering provides a forum for the rapid publication of short, structured Case Studies in Thermal Engineering and related Short Communications. It provides an essential compendium of case studies for researchers and practitioners in the field of thermal engineering and others who are interested in aspects of thermal engineering cases that could affect other engineering processes. The journal not only publishes new and novel case studies, but also provides a forum for the publication of high quality descriptions of classic thermal engineering problems. The scope of the journal includes case studies of thermal engineering problems in components, devices and systems using existing experimental and numerical techniques in the areas of mechanical, aerospace, chemical, medical, thermal management for electronics, heat exchangers, regeneration, solar thermal energy, thermal storage, building energy conservation, and power generation. Case studies of thermal problems in other areas will also be considered.