混合气体对煤中CH4置换效率的影响研究  

Study on the influence of mixed gas on CH4 replacement efficiency in coal

作　　者：吕宝艳 杨宏民[1,2] 吕晓来 邱向雷 LYU Baoyan;YANG Hongmin;LYU Xiaolai;QIU Xianglei(School of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo 454000,Henan,China;Engineering Research Center of the Ministry of Education for Coal Mine Disaster Prevention and Rescue and Disaster Relief,Jiaozuo 454000,Henan,China)

机构地区：[1]河南理工大学安全科学与工程学院,河南焦作454000 [2]煤矿灾害预防与抢险救灾教育部工程研究中心,河南焦作454000

出　　处：《河南理工大学学报（自然科学版）》2020年第4期20-26,共7页Journal of Henan Polytechnic University（Natural Science）

基　　金：国家自然科学基金资助项目(51174081);教育部创新团队发展支持计划项目(IRT-16R22);河南省高校科技创新团队支持计划项目(17IRTSTHN030)。

摘　　要：为了揭示混合气体对不同变质程度煤中CH4的置换效率及其影响因素,利用自建的多元气体置换吸附试验装置,在不同的环境温度、平衡压力、注入压力和注入气体组成比例等4个条件下,分别对无烟煤、瘦煤和气肥煤等3个典型煤种进行混合气体置换煤中CH4试验。结果表明:恒温条件下,随着平衡压力增加,混合气体的吸附/解吸能力呈现单调增加的变化,且混合气体的吸附/解吸能力表现出随置换气体的吸附能力和煤的变质程度的增加而增加,即VCO2>VCH4>VN2>VHe和V无烟煤>V瘦煤>V气肥煤;在一定平衡压力条件下,温度越高混合气体的吸附/解吸能力越小;在平衡压力和温度保持恒定时,随着注入压力的增加,纯CO2气体对CH4的置换效率会有所降低。与仅注入CO2相比,混合气体的置换效率则表现更好,即混合气体中含N2比例越高,对CH4的置换效率越好。该试验得出的启示是:井下煤层注气置换煤层CH4不一定追求高的注入压力,只要注气源配比合适,低注入压力也能获得更好的煤层瓦斯抽采率。In order to explore the replacement efficiency of CH4 and its influencing factors in different metamorphic coals,a self-built multi-gas replacement adsorption experimental device was used to carry out replacement CH4 experiments in coal by mixed gas.The experimental coal samples were selected from three typical coal types,such as anthracite,lean coal and gas-fat coal,under conditions of different adsorption temperatures,equilibrium pressures,injection pressures and composition ratio of injected gas.The results showed that under constant temperature conditions,with the increase of equilibrium pressure,the adsorption/desorption capacity of the mixed gas was of a monotonously increasing with increase of the adsorption strength of the replacement gas and the degree of coal metamorphism,i.e.,VCO2>VCH4>VN2>VHe and Vanthracite>Vlean coal>Vgas-fat coal;Under a certain equilibrium pressure condition,the higher the temperature was,the smaller the adsorption/desorption capacity of the mixed gas had got;When the equilibrium pressure and temperature remained constant,with the injection pressure increases,the replacement efficiency of pure CO2 gas for CH4 would decrease.Compared with the injection of CO2 gas,the replacement efficiency of the mixed gas was better,i.e.,the higher the nitrogen content in the mixed gas was,the better the replacement efficiency of methane was.The enlightenment obtained from this experiment was that underground coal seam gas injection to replace coal seam CH4 did not necessarily pursue its high injection pressure.As long as the gas injection source ratio was appropriate,low injection pressure could also achieve better coal seam gas recovery rate.

关 键 词：混合气体 温度 平衡压力 注入压力 煤中CH4 置换效率 

分 类 号：P618.11[天文地球—矿床学]