不同粒径煤的瓦斯解吸扩散特性实验研究

Experimental studies on gas desorption and diffusion characteristics of coal with different particle sizes

为研究粒径大小对瓦斯解吸扩散特性的影响,选取粒径为0.18~0.25 mm、0.5~1 mm、1~1.25 mm的无烟煤、长焰煤,分别进行等温等压条件下煤的瓦斯解吸实验。结果表明,对于同一变质程度的煤样,其相同时间段内的瓦斯解吸量与粒径成反比,粒径对无烟煤的瓦斯解吸量影响比长焰煤明显。随着粒径的减小,煤样在外表面和敞开大孔隙表面的解吸量增加;扩散系数减小,瓦斯扩散过程减弱。随着粒径的增大,传质毕欧准数增大,瓦斯在煤粒内部扩散阻力增大,瓦斯扩散能力减弱。

In order to study the effect of particle size on gas desorption and diffusion characteristics,anthracite coal and long-flame coal with particle sizes as 0.18 to 0.25 mm,0.5 to 1 mm,1 to 1.25 mm are selected to conduct gas desorption experiments of coal under the conditions of same gas pressure and temperature.The results show that,for the same metamorphic degree of coal,the same amount of desorption time is inversely proportional to the particle size.The influence of particle size on gas desorption capacity of anthracite is more obvious than that of long-flame coal.And as the decrease of the particle size,coal sample outer surface and big pore surface desorption quantity increase.Simultaneously the diffusion coefficient decreases,and gas diffusion process weakened.With the increase of particle size,the mass transfer Bio quasi-number increases,the gas diffusion resistance in coal particles increases,the gas diffusion capacity weakened.