Hao Jianchi, Wen Hu, Ma Li, Fei Jinbiao, Ren Lifeng
College of Safety Science and Engineering, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China.
Ministry of Education Key Laboratory of Western Mine Exploration and Hazard Prevention, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China.
ACS Omega. 2021 May 17;6(20):13275-13283. doi: 10.1021/acsomega.1c00957. eCollection 2021 May 25.
Adsorption characteristics of CO by coal are an important reservoir parameter to determine the CO storage capacity of the coal seam. The Langmuir isotherm adsorption model is commonly used to describe the isothermal adsorption line of coal. However, we cannot predict the CO adsorption capacity at other temperatures by using the Langmuir model based on the experimental data at a fixed temperature. This paper analyzes the ε- adsorption characteristic curves of three coal samples over a range of temperatures and pressures. The study demonstrates that the adsorption characteristic curves of CO gas are independent of temperature and depend mainly on the dispersion force between coal and the CO molecules. In addition, the adsorption potential of CO gas has a negative correlation with the volume of the adsorbed phase. Hence, the CO adsorption characteristic curve of coal conforms to the logarithmic function. Based on the adsorption potential theory, the prediction model of CO adsorption by coal is derived. The deviation analysis from measured data shows that the average relative deviation of the three coal samples is ∼5%, and the prediction results are accurate and reliable. Under different temperature and pressure conditions of the three coal samples, the results from the prediction model of CO adsorption by coal and the Langmuir model have a strong correlation with the experimental results. In comparison with the Langmuir model, the prediction model of CO adsorption by coal can predict the adsorption capacity under different temperature and pressure conditions. Hence, it has a wide range of applications when compared to that of the Langmuir model. In practical applications, better results are achieved with a significant reduction in experimental time and labor.
煤对CO的吸附特性是确定煤层CO储存能力的一个重要储层参数。Langmuir等温吸附模型常用于描述煤的等温吸附线。然而，基于固定温度下的实验数据，我们无法用Langmuir模型预测其他温度下的CO吸附容量。本文分析了三种煤样在一定温度和压力范围内的ε-吸附特性曲线。研究表明，CO气体的吸附特性曲线与温度无关，主要取决于煤与CO分子之间的色散力。此外，CO气体的吸附势与吸附相体积呈负相关。因此，煤的CO吸附特性曲线符合对数函数。基于吸附势理论，推导了煤对CO吸附的预测模型。与实测数据的偏差分析表明，三种煤样的平均相对偏差约为5%，预测结果准确可靠。在三种煤样的不同温度和压力条件下，煤对CO吸附的预测模型和Langmuir模型的结果与实验结果具有很强的相关性。与Langmuir模型相比，煤对CO吸附的预测模型可以预测不同温度和压力条件下的吸附容量。因此，与Langmuir模型相比，它具有更广泛的应用范围。在实际应用中，可显著减少实验时间和人力，取得更好的效果。
