低频振动对煤中瓦斯解吸特性的影响的实验及机理

低频振动对煤解吸特性的影响

李树刚1赵勇1张天军2许鸿杰2

(1.西安科技大学能源学院；2.西安科技大学基础课部；西安710054)

摘要：为研究低频振动对煤解吸瓦斯性能的影响，研制了瓦斯解吸激振与测试系统。试验研究发现：在低频振动作用下，随着频率降低，解吸量和解吸速度就越大。针对这一现象，采用振动理论和瓦斯解吸速度的相关知识，对实验结果进行了分析研究。研究认为：低频扰动会导致煤的孔隙性变小，不利于瓦斯分子的解吸。因此吸附伴生分子虽然受到脱附能，由于扩散阻力的增大，解吸速度就较慢，解吸量就小。无扰动作用时，煤样的孔隙性没有改变，虽然吸附伴生分子没有受到脱附能，解吸速度反而较快。这说明：低频振动使煤样的孔隙性减弱，增大了分子的自由程，导致分子在煤样中扩散变慢，同时增加了煤样的吸附位，从而减缓了在煤样中的解吸。

关键词:低频振动；解吸；分子自由程；吸附位

中图分类号：TD 712 文献标识码:A

Research the parse effect of experiment and mechanism which gas among coal in low oscillate frequency condition LI Shu-gang1,Zhao Yong1,Zhang Tian-jun2,Xu Hong-jie2

(1School of Energy, Xi'an University of Science and Technology; Xi'an 710054,China

2 Dept. of Basic Courses,Xi' an University of Science & Technology; Xi'an 710054,China) Abstract：In order to research the parse effect which gas among coal in low oscillate frequency condition,the author design a gas absorb vibrancy and testing system.The experiment research shows: the lower frequency of oscillation,the lower of frequency,the larger of disengage quantity and the slower of parse speed.Low frequency. without the oscillation, the bigness of disengage quantity and the faster of parse speed.Low . Aim at phenomenon,adoptting the vibrancy of engine theory and correlation knowledge about the desorption speed of gas. we expansion a series of research. The result show: with the disturb ,the hole of coal turn small ,disadvantage desorption. Therefore absorb parter molecule get miss out energy,because pervasion resistance turns large.the slower of parse speed and the smaller of disengage quantity.without the low frequency disturb, the hole of coal shape keep the same make for the gas desorption. absorb parter molecule does not get miss out energy. Parse speed show fast.It makes out that frequency oscillate reduce the hole density of coal model,increase the disengagement degree of firedamp molecule,that makes firedamp molecule’s diffusion slower,and increases the adsorption site of coal model at the same time,while the coal model’s disengage speed and disengage quantity become slower and smaller. Keywords: low oscillate frequency;disengage quantity;molecule diffusion degree;adsorption site. 1引言

煤层瓦斯解吸特性除了与煤体的孔隙性，煤质等煤体本身性质有关外，还受到地电场、地应力、地温、以及人为采掘活动影响。研究不同因素影响下煤体的瓦斯的解吸特征，对于认识煤层瓦斯的运移，以及瓦斯突出机理，煤层气开采等都具有重要意义。

国内外许多学者对于地电场、温度、地应力、电磁波等对煤层瓦斯解吸的影响规律做了大量的试验研究[1-3]，姜永东等研究超声振动对煤体解吸瓦斯规律的影响，发现超声波的振动作用使瓦斯气体在煤体上的附着力减弱, 同时煤体吸收的声能的一部分转化为热能,使瓦斯分子气与煤表面分子间的吸附作用减弱, 从而促进煤体中瓦斯气的解吸和扩散。目前，对低频振动作用下煤层瓦斯的解吸规律的研究还很少，然而煤炭采掘过程中所发生的煤与瓦斯突出事故大多与爆破、钻探等动态扰动载荷有关。为了研究这些低频扰动载荷对煤体解吸瓦斯的影响规律，自主研发了瓦斯吸附/解吸激振及测试系统，利用该装置对煤样在低频振动