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孟祥宁,梁运涛,郭宝龙,等. 卤盐阻化剂对煤自燃阻化作用的定量识别及机理[J]. 煤炭科学技术,2024,52(6):132−141. doi: 10.12438/cst.2023-1849
引用本文: 孟祥宁,梁运涛,郭宝龙,等. 卤盐阻化剂对煤自燃阻化作用的定量识别及机理[J]. 煤炭科学技术,2024,52(6):132−141. doi: 10.12438/cst.2023-1849
MENG Xiangning,LIANG Yuntao,GUO Baolong,et al. Quantitative identification and mechanism of spontaneous coal combustion inhibition by halogen inhibitor[J]. Coal Science and Technology,2024,52(6):132−141. doi: 10.12438/cst.2023-1849
Citation: MENG Xiangning,LIANG Yuntao,GUO Baolong,et al. Quantitative identification and mechanism of spontaneous coal combustion inhibition by halogen inhibitor[J]. Coal Science and Technology,2024,52(6):132−141. doi: 10.12438/cst.2023-1849

卤盐阻化剂对煤自燃阻化作用的定量识别及机理

Quantitative identification and mechanism of spontaneous coal combustion inhibition by halogen inhibitor

  • 摘要: 煤自燃灾害严重影响煤矿安全生产,卤盐阻化是防治煤自燃灾害的主要措施之一。优化阻化工艺、提高阻化效果的前提是掌握阻化剂的物理、化学阻化作用机制。为此,探究卤盐阻化剂对煤自燃的主要抑制方式,明确其物理、化学作用对煤层阻化的贡献比显得尤为重要。基于此,提出一种定量识别卤盐阻化剂阻化作用的方法。本次研究卤盐中具有代表性的MgCl2阻化剂,采用超声波清洗器多次反复冲洗阻化煤样和水洗煤样,得到水洗阻化煤样和水洗参考煤样。通过程序升温试验和红外光谱试验研究不同煤样的指标气体浓度、交叉点温度、阻化率和活性基团的变化规律,从宏微观角度研究卤盐阻化剂的物理、化学阻化作用。结果表明:水洗阻化煤样的产气浓度、交叉点温度、阻化率和活性基团含量明显低于原煤样,却高于阻化煤样,这说明MgCl2阻化剂对煤自燃起到协同抑制作用,具有物理化学双重阻化效果。煤氧化反应前期,物理阻化作用大于化学阻化作用,煤氧化反应后期,化学阻化作用占主导地位,明显高于物理阻化作用。MgCl2的化学抑制作用体现在能与煤中活性物质反应生成比较稳定的物质(ROCl)和镁络合物(Mg(OH)Cl),使得煤的活性下降,从而降低了煤的自热风险。MgCl2阻化剂物理、化学阻化作用对平庄褐煤的贡献比分别为56.37%和43.63%,对同忻烟煤的贡献比为57.91%和42.09%,对白芨沟无烟煤的贡献比为59.60%和40.40%。随着煤样变质程度的增加,物理阻化作用贡献比增加,化学阻化作用贡献比减小,平庄褐煤的化学阻化作用是白芨沟无烟煤的1.08倍。该研究有助于丰富卤盐阻化剂的阻化机理,并为优化防灭火工艺提供理论指导。

     

    Abstract: The spontaneous coal combustion seriously affects the safety production of coal mine, and halogenation is one of the main measures to prevent and control the spontaneous coal combustion. The prerequisite for optimizing the inhibition process and improving the inhibition effect is to master the physical and chemical inhibition mechanism of inhibitor. Therefore, it is particularly important to explore the main inhibition methods of spontaneous coal combustion by halogen inhibitor, and to determine the contribution ratio of the physical and chemical inhibition to coal seam. Based on this, a method was proposed to quantitatively identify the inhibition effect of halogen inhibitor. The representative MgCl2 inhibitor in halogenation was selected, the ultrasonic washer was used to repeatedly rinse the inhibiting and washing coal samples to obtain the experimental and reference coal samples. The change law of index gas concentration, cross point temperature, retarding rate and active functional group of different coal samples was investigated by temperature programmed experiments and infrared spectrum experiments. The physical and chemical retarding effect of halide retarder was studied from both macro and micro perspectives. The results indicated that the gas production concentration, cross-point temperature, inhibition rate and active functional group content of the washed and inhibited coal sample were significantly lower than those of the original coal sample, but higher than those of the inhibited coal sample. This suggested that the MgCl2 inhibitor had a synergistic effect on inhibiting the spontaneous coal combustion and possessed a dual physicochemical inhibition effect. In the initial stage of coal oxygen reaction, there was a greater physical resistance compared to chemical resistance. However, in the later stages of the reaction, the chemical resistance dominated and significantly surpassed the physical resistance. The chemical inhibition effect of MgCl2 was reflected in that it can react with the active substances in coal to form a relatively stable substance (ROCl) and magnesium complex (Mg(OH)Cl). This transformation significantly diminished the reactivity of coal, thereby mitigated the potential risk of coal self-heating. The contribution ratios of physical and chemical effects of MgCl2 inhibitors to Pingzhuang lignite were 56.37% and 43.63%, to Tongxin bituminous coal 57.91% and 42.09%, and to Baijigou anthracite 59.60% and 40.40%. With the increase of metamorphism degree of coal samples, the contribution ratio of physical resistance increased, and the contribution ratio of chemical resistance decreased. The chemical resistance ratio of Pingzhuang lignite was 1.08 times that of Baijigou anthracite. This paper was of great significance to the mechanism of the rich halide inhibitor and provides theoretical guidance for optimizing the fire prevention process.

     

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