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温氧双变量驱动下煤耗氧与CO生成动力学模型

Kinetic model of coal oxygen consumption and CO generation driven by temperature and oxygen as dual variables

  • 摘要: 在煤矿开采与存储过程中存在煤自燃风险,可能引发CO(一氧化碳)中毒等事故,煤氧化速率是影响煤自燃进程的重要因素,而环境氧体积分数和温度是影响煤氧化速率和CO生成速率的关键参数。为探究煤的耗氧速率(\phi )、CO生成速率(\varphi )与环境氧体积分数、温度之间的内在联系,以红庆梁煤样为研究对象开展封闭耗氧实验。通过控制温度在20~70 ℃(煤自燃潜伏期)范围,同步监测并记录了氧气体积分数(c)和CO体积分数(g)随时间变化的曲线,提出了因实验条件差异导致的不同空气/煤体积比的耗氧系数(\lambda _\mathrmc)与CO生成系数(\lambda _\mathrmc\left( \mathrmCO \right) )的修正方法,并通过回归分析,推导出不同氧体积分数及温度条件下煤的耗氧速率(\phi )与CO生成速率(\varphi )的二元函数关系式。结果表明:关系式中耗氧系数(\lambda _\mathrmc)、CO生成系数(\lambda _\mathrmc\left( \mathrmCO \right) )、耗氧临界氧体积分数(\varepsilon _\mathrmb)和CO极限体积分数(\varepsilon _\mathrmb\left( \mathrmCO \right) )均是关于温度的函数。当温度从20℃升至70℃时,耗氧系数(\lambda _\mathrmc)和CO生成系数(\lambda _\mathrmc\left( \mathrmCO \right) )随温度升高呈现指数变化规律,耗氧临界氧体积分数(\varepsilon _\mathrmb)呈线性下降趋势,CO极限体积分数(\varepsilon _\mathrmb\left( \mathrmCO \right) )呈线性上升趋势。最终,基于实验数据与分析结果,建立了以氧气体积分数和温度为变量的耗氧速率(\phi )及CO生成速率(\varphi )函数模型。研究成果进一步丰富了煤自燃理论,可以为煤自燃相关数值模拟提供理论指导,为煤矿防灭火提供科学依据。

     

    Abstract: There is a risk of coal spontaneous combustion during coal mining and storage, which may cause accidents such as CO (carbon monoxide) poisoning. Coal oxidation rate is an important factor affecting the process of coal spontaneous combustion, while ambient oxygen volume fraction and temperature are key parameters affecting coal oxidation rate and CO generation rate. In order to explore the intrinsic relationship between coal oxygen consumption rate (\phi ), CO generation rate(\varphi ), ambient oxygen volume fraction and temperature, a closed oxygen consumption experiment is carried out with Hongqingliang coal samples as the research object. By controlling the temperature in the range of 20~70 ℃ (the latent period of coal spontaneous combustion), the curves of oxygen volume fraction (c) and CO volume fraction (g) changing with time are synchronously monitored and recorded. The correction method for oxygen consumption coefficient (\lambda _\mathrmc) and CO generation coefficient (\lambda _\mathrmc\left( \mathrmCO \right) ) of different air/coal volume ratios caused by experimental conditions is proposed; and the binary function relationship between oxygen consumption rate (\phi ) and CO generation rate (\varphi ) of coal under different oxygen volume fractions and temperature conditions is derived through regression analysis. The results show that: the oxygen consumption coefficient (\lambda _\mathrmc), CO generation coefficient (\lambda _\mathrmc\left( \mathrmCO \right) ), critical oxygen volume fraction of oxygen consumption (\varepsilon _\mathrmb), and CO limit volume fraction (\varepsilon _\mathrmb\left( \mathrmCO \right) ) in the equation are all functions of temperature. When the temperature rises from 20 °C to 70 °C, the oxygen consumption coefficient (\lambda _\mathrmc) and the CO generation coefficient (\lambda _\mathrmc\left( \mathrmCO \right) ) show an exponential change pattern with the increase of temperature; the critical oxygen volume fraction of oxygen consumption (\varepsilon _\mathrmb) shows a linear downward trend; and the CO limit volume fraction (\varepsilon _\mathrmb\left( \mathrmCO \right) ) shows a linear upward trend. Finally, based on the experimental data and analysis results, the function model for the oxygen consumption rate (\phi ) and the CO generation rate (\varphi ) is established, with oxygen volume fraction and temperature as variables. The research results further enrich the theory of coal spontaneous combustion, which can provide theoretical guidance for numerical simulations related to coal spontaneous combustion; this provides also scientific evidence for fire prevention and control in coal mines.

     

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