受振粒煤瓦斯扩散特性实验研究

Experimental study on gas diffusion characteristics of vibrating granular coal

为了探究机械振动对粒煤瓦斯扩散特性的影响,建立振动-吸附-解吸实验系统,选取桧树亭矿1~3 mm和0.25~0.3 mm粒径的贫煤,开展煤样瓦斯解吸-扩散实验,采用瓦斯气体扩散模型进行分析振动前后不同粒径的煤样的解吸-扩散情况。结果表明:施加振动能够提升粒煤的瓦斯扩散量和扩散速度,初始有效扩散系数在振动过程中也得到了提升。通过对比发现,小粒径煤样具有相对较小的扩散系数,在解吸前期拥有较大的扩散速度,振动对其扩散特性的影响较大。分析认为,一方面,小粒径煤样的振动作用的增强,导致振动产生的外力作用越明显,进而加剧了瓦斯扩散程度;另一方面,粒径大的煤样具有更大的表面积,与小粒径煤样相比,能够吸附的瓦斯更多,因此初始扩散速度较大。

In order to explore the influence of mechanical vibration on the gas diffusion characteristics of granular coal,the self-developed vibration-gas adsorption-desorption experimental platform was used to conduct the gas desorption-diffusion experiments of coal samples with different particle sizes before and after vibration.The dynamic diffusion coefficient model was used to select the lean coal of 1-3 mm and 0.25-0.3 mm in Guishuting Mine,respectively.The gas desorption-diffusion experiment of coal samples was carried out,and the vibration of coal samples with different particle sizes before and after was compared.The results show that the application of vibration can increase the gas diffusion amount and diffusion speed of granular coal,and the initial effective diffusion coefficient of gas desorption is also improved.The initial effective diffusion coefficient of small particle size coal sample is smaller than that of large particle size coal sample,but the early diffusion rate is larger,and the vibration has a greater impact on the diffusion characteristics.It is pointed out that,on the one hand,the enhancement of vibration effect of small-size coal samples leads to more obvious external force generated by vibration,which further aggravates the degree of gas diffusion.On the other hand,coal samples with large particle size have larger surface area,and can absorb more gas than coal samples with small particle size,so the initial diffusion rate is larger.