Effect of the Pore Structure on Adsorption and Diffusion Migration of Different Rank Coal Samples,Energy & Fuels

当前位置： X-MOL 学术 › Energy Fuels › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Effect of the Pore Structure on Adsorption and Diffusion Migration of Different Rank Coal Samples
Energy & Fuels ( IF 5.2 ) Pub Date : 2020-09-21 , DOI: 10.1021/acs.energyfuels.0c02587
Lin Wang _{1,

2,

3} , Guixin Zhang ₁ , Jun Liu _{1,

2,

3} , Xiangjun Chen _{1,

2,

3} , Zhiqiang Li _{1,

2,

3}

Affiliation

Existing experimental equipment was used to conduct high-temperature and -pressure diffusion tests on four coal samples with different low, middle, and high ranks. Then, the characteristics of the diffusion kinetics of coal samples under different temperatures and pressures are discussed by using the results. Meanwhile, a high-temperature and -pressure methane diffusion model was derived and established by combining with the molecular simulation of methane adsorption and diffusion. Finally, the mechanism of methane diffusion in coal samples is discussed by combining the pore structure and heterogeneity of coal samples. The results show that the adsorption capacity and isosteric heat of adsorption calculated by molecular simulation gradually decrease as the temperature increases. Comparing the methane self-diffusion coefficient and corrected diffusion coefficient with the transfer diffusion coefficient of coal samples at different temperatures, it can be seen that the values of three diffusion coefficients all increase with the increase of temperature. Under the same temperature and different pressures, the initial diffusion coefficient calculated by the new model gradually increases with the increase of pressure. With the increase of temperature, the attenuation coefficient by using new models first increases and then decreases under the conditions of 2, 6, and 12 MPa; it gradually decreases under the condition of 20 MPa. As the degree of coal rank increases, the diffusion coefficient, specific surface area, and fractal dimension all first decrease and then increase later. Then, the diffusion coefficient gradually increases with the increase of the fractal dimension, and there is a positive correlation between the two parameters. It shows that the more complex the pore structure of coal and the rougher the surface, the greater the impact on the methane diffusion coefficient.

中文翻译：

孔隙结构对不同煤阶吸附和扩散迁移的影响

现有的实验设备被用来对四个低，中，高等级的煤样品进行高温和高压扩散测试。然后，利用结果讨论了煤样品在不同温度和压力下的扩散动力学特征。同时，结合甲烷吸附扩散过程的分子模拟，建立并建立了高温高压甲烷扩散模型。最后，结合煤样的孔隙结构和非均质性，探讨了煤样中甲烷的扩散机理。结果表明，随着温度的升高，分子模拟计算得到的吸附容量和等排热逐渐降低。将甲烷自扩散系数和校正后的扩散系数与煤在不同温度下的传递扩散系数进行比较，可以看出三个扩散系数的值均随温度的升高而增加。在相同温度和不同压力下，新模型计算出的初始扩散系数随着压力的增加而逐渐增加。随着温度的升高，使用新模型的衰减系数在2、6和12 MPa的条件下先增大然后减小。在20MPa的条件下逐渐降低。随着煤等级的增加，扩散系数，比表面积和分形维数都先下降，然后再增加。然后，扩散系数随分形维数的增加而逐渐增加，且两个参数之间呈正相关。结果表明，煤的孔隙结构越复杂，表面越粗糙，对甲烷扩散系数的影响就越大。

更新日期：2020-10-16

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11