Abstract

The dependence of the diameter of a porous carbon particle on stationary temperature at various gas mixture pressures is analyzed. The cases of particle self-ignition in a heated nitrogen–oxygen mixture and forced ignition in a cold nitrogen–oxygen mixture that lead to quasi-stationary combustion, followed by spontaneous extinction, are considered. It is shown that the combustion temperature of small particles with a diameter \(d<200\) \(\mu\)m, which are characterized by a transient regime of chemical reactions, increases with increasing pressure of the gas mixture. An analytical dependence qualitatively describing this dynamics is obtained. The greatest increase is observed in the pressure range 0.1–0.3 MPa. A similar analysis is performed for particles of various coals. The dependence of the critical oxygen concentrations corresponding to ignition and extinction on carbon particle diameter was obtained analytically taking into account the internal reaction. It is shown that increasing the mixture pressure leads to a decrease in the critical oxygen concentrations.

中文翻译：

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混合气体压力对不同多态性煤炭自燃，自燃和自熄的影响

摘要

分析了在各种气体混合物压力下，多孔碳颗粒的直径与固定温度的关系。考虑了在加热的氮气-氧气混合物中发生粒子自燃以及在冷的氮气-氧气混合物中进行强制点燃的情况，这些燃烧会导致准静态燃烧，然后自然熄灭。结果表明，直径为\（d <200 \） \（\ mu \）的小颗粒的燃烧温度 m以化学反应的瞬态形式为特征，随气体混合物压力的增加而增加。获得定性描述这种动力学的分析依赖性。在0.1-0.3 MPa的压力范围内观察到最大的增加。对各种煤的颗粒进行了类似的分析。考虑到内部反应，通过分析获得了对应于着火和消光的临界氧浓度对碳粒径的依赖性。结果表明，增加混合物压力会导致临界氧浓度降低。