煤层对CO2、CH4和N2吸附/解吸规律研究

针对目前我国煤层气开发中存在的产气率低、煤层气开采理论规律研究欠缺等问题，根据试验对比分析了不同温度15、20、25、30℃时，CO2、CH4和N2在煤岩中的吸附／解吸规律。试验结果表明,当温度升高时，气体分子的平均自由程越大，气体吸附量变小；对同一种煤介，当压力相同时，临界温度高的气体，具有较强的吸附能力，煤层对CO2、CH4和N2吸附能力依次下降；压力升高时，煤层对气体的吸附量变大；降压解吸过程存在解吸滞后现象，温度降低显著，这与吸附、解吸表达式和吸热反应有关。

Study on CO2, CH4 and N2 Adsorption and Desorption Law of Seam

According to the low methane gas production rate,insufficient study on the coal bed methane mining theoretical law and other problems existed in China coal bed methane development,based on the test comparisons,the adsorption and desorption laws of CO₂,CH₄ and N₂ in coal and rock were analyzed with different temperatures of 15,20,25 and 30 ℃.The test results showed that when the temperature raised,the higher the mean free path of the gas molecules,the smaller the gas adsorption value would be.As for the same medium,when the pressure was the same,the gas with a high critical temperature would have a high adsorption capacity and the CO₂,CH₄ and N₂ adsorption capacity of the seam would reduce in sequence.When the pressure increased,the gas adsorption value of the seam would be increased.There was an desorption hysteresis existed in the pressure releasing and desorption process.When the temperature decreased,the desorption hysteresis would be obvious which was related to the adsorption and desorption expression and the endothermic reaction.