DL-malic acid for inhibiting the re-ignition of long-flame coal and its micro-reaction mechanism

IF 16.4 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Accounts of Chemical Research Pub Date : 2024-01-23 DOI:10.1002/apj.3027

Yun-chuan Bu, Hui-yong Niu, Hai-yan Wang, Tian Qiu, Yan-xiao Yang

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Abstract

To study the metal ion chelating agent (DL-malic acid) inhibiting oxidation characteristics of residual coal in goaf, the microscopic thermal transformation characteristics of the treated coal samples were obtained using apparent morphology, infrared spectroscopy, free radical testing, and thermal analysis. The results demonstrate that after the addition of malic acid, the sphericity and roundness of the coal samples decrease, and the small fractured particles accumulate in the pores of the oxidized coal samples and, thereby, reduce the number of coal–oxygen contact sites. The addition of 10% malic acid promotes the conversion of functional groups (FG) and free radicals in pre-oxidized coal, inhibits the catalytic effect of metal ions, generates more active sites, and increases the total heat release during the combustion process. There are strong endothermic points in the malic acid-treated coal samples, and the free water evaporation blocked by small particles in the holes delays the initial heat release temperature of the coal samples. Pre-oxidation can promote changes in the valence state of metal ions in coal, increase the adhesion between broken pre-oxidized coal particles via malic acid chelation, and lose the catalytic effect of metal ions; this inhibits the process of oxidative re-ignition of coal samples.

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抑制长焰煤复燃的 DL-苹果酸及其微反应机理

为了研究金属离子螯合剂（DL-苹果酸）抑制残煤在煤层中氧化的特性，采用表观形态学、红外光谱、自由基测试和热分析等方法获得了处理后煤样的微观热变特性。结果表明，添加苹果酸后，煤样的球度和圆度降低，氧化煤样的孔隙中积聚了细小的断裂颗粒，从而减少了煤与氧气的接触点。10% 苹果酸的加入促进了预氧化煤中官能团（FG）和自由基的转化，抑制了金属离子的催化作用，产生了更多的活性位点，增加了燃烧过程中的总放热量。经苹果酸处理的煤样存在较强的内热点，孔中的小颗粒阻挡了自由水的蒸发，延迟了煤样的初始放热温度。预氧化可促进煤中金属离子价态的变化，通过苹果酸螯合作用增加预氧化煤颗粒间的粘附力，使金属离子失去催化作用，从而抑制煤样的氧化复燃过程。

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来源期刊

Accounts of Chemical Research 化学-化学综合

CiteScore

31.40

自引率

1.10%

发文量

312

审稿时长

2 months

期刊介绍： Accounts of Chemical Research presents short, concise and critical articles offering easy-to-read overviews of basic research and applications in all areas of chemistry and biochemistry. These short reviews focus on research from the author’s own laboratory and are designed to teach the reader about a research project. In addition, Accounts of Chemical Research publishes commentaries that give an informed opinion on a current research problem. Special Issues online are devoted to a single topic of unusual activity and significance. Accounts of Chemical Research replaces the traditional article abstract with an article "Conspectus." These entries synopsize the research affording the reader a closer look at the content and significance of an article. Through this provision of a more detailed description of the article contents, the Conspectus enhances the article's discoverability by search engines and the exposure for the research.