氧浓度与风量对煤热物性参数影响的实验研究

摘要

In order to study the influence of oxygen concentration and blowing rate on heat transfer characteristics in the process of coal spontaneous combustion,laser thermal analysis experiments were carried out to identify specific heat,thermal diffusion coefficient and thermal conductivity characteris-tics under the conditions of different oxygen concentrations and blowing rates.The thermal conductivity of the coal sample showed a downward trend with the rising of temperature,yet heat capacity increased linearly.The coefficient of thermal conductivity was slowly nonlinear growth with the increasing of the temperature.The thermal diffusion coefficient of coal under pure oxygen condition was slightly higher than that at air atmosphere,and the specific heat capacity was lower than that at air temperature,resul-ting in comprehensive performance of nonobvious effect on the thermal conductivity of coal during the heating process of coal.The increase of bolwing rate significantly reduced the thermal diffusion coeffi-cient and specific heat capacity of the coal samples,leading to the reducing of thermal conductivity of coal.The results show that oxygen concentration has little impact on heat transfer characteristics in coal oxidation process,but blowing rate affects the thermal conductivity significantly,which is the important factor of heat transfer during coal spontaneous combustion.%为了研究氧浓度与风量对煤自燃过程传热特性的影响,采用激光导热分析仪,研究了不同氧浓度与风量条件下煤的热扩散系数、比热容与导热系数变化特征,发现煤样的热扩散系数随温度的升高总体呈下降趋势,而比热容表现为线性增加,导热系数随着温度的升高呈缓慢的非线性增长特征;纯氧条件下煤的热扩散系数略高于空气气氛,比热容则低于空气气氛,综合效应表现为氧浓度对煤升温过程中导热系数无明显影响;而供风量的增加明显降低了煤样的热扩散系数与比热容,综合表现为导热系数的降低.结果表明:氧浓度对煤氧化升温过程传热特性影响较小,而风量对实验煤样导热系数的变化具有显著影响,是煤自燃传热过程研究应考虑的重要因素.