煤中二元气体竞争吸附与置换解吸的差异性及其置换规律

煤对气体的吸附有强弱之分,多元气体之间存在竞争吸附和置换解吸。他们之间会不会因为气体进入的先后顺序不同而产生差异呢?为此进行了煤对CH4-CO2混合气体的竞争吸附和CO2置换煤中CH4的置换吸附对比实验。实验表明,煤对CH4-CO2二元气体的竞争吸附与置换解吸结果是一致的,理论分析表明煤对气体的吸附解吸与气体进入煤体先后顺序和过程无关,只与吸附前后的状态有关。气体置换煤中CH4的规律为:混合气体中强吸附性气体含量越大,置换效率越高;置换压力越大置换效率越高。最后对煤层注气措施提出了建议:应先将煤层瓦斯压力降到安全范围再实施注气措施。

Differences between competitive adsorption and replacement desorption of binary gases in coal and its replacement laws

Adsorption has some differences for multi-gases in coal,such as strong and weak adsorption.There are competitive adsorption and replacement desorption within multi-gases.Is there a different testing result between competitive adsorption and replacement desorption because the order of gases ejected coal? To answer the question,a couple of contrast tests were designed between competitive adsorption of CH4-CO2 binary mixture and replacement desorption by CO2 injection after CH4 adsorption equilibrium.The study indicates that the testing results of CH4-CO2 binary gas absorption in coal are coincident between the methods of competitive adsorption and replacement desorption.The theoretical analysis shows that there is no relation between gases adsorptive capacity and sequencing or process of gas into coal sample,however,a relation with the conditions of starting and ending of absorption.The laws of gases replacement methane in coal show:the more concentration of strong absorption gas,the more replaced methane content,and the higher replacement pressure,the higher replacement efficiency.The study suggests that the coalbed gas pressure should be reduced to a safety range by releasing or draining coalbed gas first,and then the gas injection measures should be taken.