煤与页岩中瓦斯解吸特性对比实验研究

Experimental Study on Desorption Characteristics of Gas in Coal and Shale

为了分析煤与页岩中瓦斯解吸特性,以四川盆地龙马溪组黑色页岩和重庆南桐煤矿无烟煤为研究对象,利用瓦斯吸附/解吸装置,开展了不同温度条件下的瓦斯解吸实验,研究结果表明:瓦斯初始解吸速率极快,随着时间的增加,解吸速率逐渐减小,解吸量最终达到最大值;随着温度的增加,瓦斯最终解吸量增大,煤的解吸量增幅明显大于页岩;同等条件下煤在瓦斯解吸量和解吸时间上大于页岩,但页岩的瓦斯解吸速率大于煤。基于渗透模型,通过引入曲率的概念,将瓦斯解吸过程划分为急速解吸、快速解吸、缓慢解吸、极缓解吸4个阶段。

In order to analyze the desorption characteristics of gas in coal and shale,taking black shale of Longmaxi in Sichuan basin and anthracite coal of Nantong Coal Mine in Chongqing as subjects,the adsorption/desorption device was used to the experimental research which was carried out under different temperatures. The results showed that the gas desorption rate is very fast at first but decreases slowly as time goes on,and the amount of desorption eventually reaches its maximum. With the increase of temperature,the final desorption of gas increases,the increase of coal desorption is obviously larger than that of shale. Desorption quantity and desorption time of coal are greater than shale under the same condition. On the contrary,the desorption rate of shale is faster than that of coal. Based on the permeability model,the desorption process was divided into four stages： very fast desorption,fast desorption,slow desorption and very slow desorption by introducing the concept of curvature.