温度冲击作用参数对泥岩甲烷吸附解吸特性的影响正交试验研究

    An orthogonal experimental study on the effect of temperature shock parameters on methane adsorption and desorption properties of mudstone

    • 摘要: 为研究温度冲击作用参数对泥岩甲烷吸附解吸特性的影响,采用正交试验的方法,对寺河煤矿15号煤层15303工作面上顶板粉砂质泥岩进行温度冲击改性试验;正交试验中的3因素4水平分别为热冲击温度50、100、150、200 ℃,冷冲击温度−10、−30、−50、−70 ℃,冲击循环次数1、3、5、7次;采用容量法测定泥岩的吸附解吸特征参数,并从孔隙结构、表面性质等方面去探究其影响机理。研究结果表明:在不同作用参数改性后泥岩甲烷吸附与解吸能力提高,对泥岩饱和吸附量、Langmuir压力、比表面积与最可几孔径影响效果顺序为热冲击温度>循环次数>冷冲击温度;对解吸率、扩散系数与孔容的影响效果顺序为:循环次数>冷冲击温度>热冲击温度;饱和吸附量分别在热冲击温度200 ℃、冷冲击温度−50 ℃、冲击循环次数3次时提高最多,分别为23.29%,15.60%、19.15%;最终解吸率分别在热冲击温度150 ℃、冷冲击温度−70 ℃、冲击循环次数5次时提高最多,分别为7.15%、11.54%、11.14%;在孔隙结构方面,泥岩的饱和吸附量与比表面积、最可几孔径有较好的线性关系,解吸率与孔容有较好的线性关系,而改性后泥岩的比表面积与孔容提高、最可几孔径降低导致泥岩的甲烷吸附与解吸能力提高;在表面性质方面,改性后泥岩的表面粗糙度降低,泥岩-水接触角增大,表面能减小。

       

      Abstract: In order to investigate the effect of temperature shock action parameters on the methane adsorption and desorption of mudstone, a temperature shock modification test was conducted on the mudstone in the roof of 15303 working face of 15# coal seam in Sihe Coal Mine using orthogonal test method. The 3 factors and 4 levels were hot shock temperature of 50, 100, 150 and 200 ℃, cold shock temperature of −10, −30, −50 and −70 ℃, and the number of shock cycles of 1, 3, 5 and 7. The volumetric method was used to determine the characteristic parameters of adsorption and desorption of mudstone under different action parameters and to investigate the influence mechanism in terms of pore structure. The results showed that the mudstone methane adsorption and desorption capacity increased after modification with different action parameters, and the effects on the saturation adsorption capacity, Langmuir pressure, specific surface area and most probable pore size were in the following order: heat shock temperature > number of cycles > cold shock temperature; the effects on the desorption rate, diffusion coefficient and pore volume were in the following order: number of cycles > cold shock temperature > heat shock temperature. The saturation adsorption capacity increased the most at the heat shock temperature of 200 ℃, the cold shock temperature of −50 ℃ and the number of shock cycles of 3 times, 23.29%, 15.60% and 19.15% respectively; the final desorption rate increased the most at the heat shock temperature of 150 ℃, the cold shock temperature of −70 ℃ and the number of shock cycles of 5 times, 7.15%, 11.54% and 11.14% respectively. In terms of pore structure, the saturated adsorption capacity of the mudstone has a good linear relationship with the specific surface area and the most available pore size, and the desorption rate has a good linear relationship with the pore capacity, while the specific surface area and pore volume of the modified mudstone are increased and the most probable pore size is reduced resulting in increased methane adsorption and desorption capacity of the mudstone. In terms of surface properties, the modification reduces the surface roughness, increases the mudstone-water contact angle and reduces the surface energy.

       

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