复采煤层孔隙结构变化及自燃特性研究

Study on the Pore Structure Change and Spontaneous Combustion Characteristics of Repeated Coal Seam

为了研究复采煤层的自燃发火规律,采用程序升温实验与低温液氮吸附实验,对复采与原生煤样的孔隙结构和自燃特性进行实验研究。研究表明,由于复采煤样前期的开采破坏,复采煤样的微孔以及小孔所占百分比增大4.395%,比表面积是原生煤样的1.48倍。复采与原生煤样均出现滞后现象,但在相同压力时,复采煤样剩余吸附量与吸附量之差要大于原生煤样,复采煤样最大吸附量也要多于原生煤样。此外,复采煤样也拥有更多墨水瓶孔,最终导致复采煤样吸附氧的能力要大于原生煤样,氧化反应更加剧烈,更易自燃发火。宏观表现为复采煤样产生的CO浓度以及耗氧速率均高于原生煤样。

In order to study the spontaneous combustion law of the repeated seam,the pore structure and spontaneous combustion characters of the repeated and the original coal samples are studied by the programmed temperature experiment and the low temperature liquid nitrogen adsorption experiment. The results show that the percentage of micro-pores and pores in the coal samples increases by 4. 395% and the specific surface area is 1. 48 times of the original coal samples due to the early production machinery cutting. The hysteresis of both repeated and original coal samples is observed. Compared with the original coal,the difference of residual adsorption capacity and adsorption capacity of the repeated coal samples is larger and the maximum adsorption capacity of repeated samples is more than that of the original samples. In addition,repeated coal samples also have more ink bottle holes,and ultimately lead to more coal mining capacity to absorb oxygen than the original coal sample and the oxidation reaction is more intense and more spontaneous combustion. The CO concentration and oxygen consumption rate of repeated coal samples are higher than those of the primary coal samples.