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首页> 外文期刊>Fire Safety Journal >Spontaneous combustion coal parameters for the Crossing-Point Temperature (CPT) method in a Temperature-Programmed System (TPS)
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Spontaneous combustion coal parameters for the Crossing-Point Temperature (CPT) method in a Temperature-Programmed System (TPS)

机译：程序升温系统（TPS）中的交叉点温度（CPT）方法的自燃煤参数

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摘要

Coal fires originate from coal spontaneous combustion caused by oxidation starting even at low temperatures. In order to evaluate the heating and oxidation of coal placed inside a container, a Temperature-Programmed System (TPS) is used under various flow and oxidation conditions for temperatures ranging from 40 to 250 degrees C. As the coal samples are heated in the container within the TPS, the concentration histories of the gaseous products are measured as well as the temperature history at the center of the container. The Crossing-point Temperature (CPT) is the temperature (temperature and corresponding time) at which the increasing coal temperature is equal to the increasing oven temperature within the TPS. We have developed energy and oxygen mass conservation equations for the coal pile in a container inside the TPS oven assuming uniform conditions for temperature and oxygen concentrations, both assumptions partially justified because the heating rate in the oven is very low (1 degrees C/min). By subtracting the convective heat from the thermal inertia of the coal pile in the energy equation, we have obtained from the experimental data the heat owing to oxygen reaction or moisture evaporation. From the oxygen conservation and measurements, we have determined apparent activation energy and pre-exponential factor for oxidation assuming that oxidation is proportional to oxygen concentration. This information is useful for the mathematical modeling of oxidation and heating in the present experiments. Subsequently, the energy and mass conservation equations were solved after being transformed to non dimensional form, which shows that four dimensionless parameters control the heating of coal in the present experiments. Only three of these parameters are examined in detail, namely a dimensionless flow time, a heat release parameter B, and a Damkohler number Da whereas a moisture parameter is discussed qualitatively. Based on the present analysis and data, four stages are identified: (I) initial heating with essentially no reaction or evaporation, (II) evaporation period with essentially no reaction, (III) an unsteady accelerated oxidation period during which crossover may occur and (IV) a heating late period where all the oxygen reacts inside the container.
机译：煤火源于即使在低温下也由氧化引起的煤自燃。为了评估放置在容器中的煤的加热和氧化，在各种流量和氧化条件下，温度程序控制系统（TPS）在40至250摄氏度的温度范围内使用。随着煤样品在容器中加热在TPS中，测量气态产物的浓度历史记录以及容器中心的温度历史记录。交叉点温度（CPT）是指升高的煤温度等于TPS内升高的炉温的温度（温度和相应的时间）。我们为TPS烤箱内的一个集装箱中的煤堆开发了能量和氧气质量守恒方程，假设温度和氧气浓度的条件相同，这两个假设部分成立，因为烤箱的加热速率非常低（1摄氏度/分钟） 。通过从能量方程中的煤堆热惯性中减去对流热，我们从实验数据中获得了由于氧反应或水分蒸发而产生的热。通过氧气的保存和测量，假设氧化与氧气浓度成正比，我们已经确定了氧化的表观活化能和指数前因子。该信息可用于本实验中氧化和加热的数学建模。随后，将能量守恒和质量守恒方程转化为无量纲形式后得到求解，表明本实验中四个无因次参数控制了煤的加热。仅详细检查了其中三个参数，即无因次流动时间，放热参数B和Damkohler数Da，而对水分参数进行了定性讨论。根据目前的分析和数据，确定了四个阶段：（I）基本上没有反应或没有蒸发的初始加热；（II）基本上没有任何反应的蒸发阶段；（III）可能发生交叉的不稳定的加速氧化阶段；以及IV）加热后期，所有氧气在容器内反应。

著录项

  • 来源
    《Fire Safety Journal》 |2017年第7期|147-154|共8页
  • 作者

    Xu Yong-liang; Wang Lan-yun; Tian Ning; Zhang Jian-ping; Yu Ming-gao; Delichatsios Michael A.;

  • 作者单位

    Henan Polytech Univ, Coll Safety Sci & Engn, Jiaozuo 454003, Peoples R China|Ulster Univ, Sch Built Environm, FireSERT, Newtownabbey BT37 0QB, North Ireland|Collaborat Innovat Ctr Coal Safety Prod Henan Pro, Jiaozuo 454003, Peoples R China;

    Henan Polytech Univ, Coll Safety Sci & Engn, Jiaozuo 454003, Peoples R China|Collaborat Innovat Ctr Coal Safety Prod Henan Pro, Jiaozuo 454003, Peoples R China;

    Ulster Univ, Sch Built Environm, FireSERT, Newtownabbey BT37 0QB, North Ireland;

    Ulster Univ, Sch Built Environm, FireSERT, Newtownabbey BT37 0QB, North Ireland;

    Henan Polytech Univ, Coll Safety Sci & Engn, Jiaozuo 454003, Peoples R China|Collaborat Innovat Ctr Coal Safety Prod Henan Pro, Jiaozuo 454003, Peoples R China;

    Ulster Univ, Newtownabbey BT37 0QB, North Ireland;

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  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    Spontaneous combustion of coal; Endothermic stages; Crossing Point Temperature; A Damkohler number;

    机译：煤炭自燃;吸热阶段;交点温度;Damkohler数;

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