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水分对CH4和CO2在煤中竞争吸附特性影响研究

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为研究水分对CH4 和CO2 及混合气体在煤中竞争吸附的影响,通过自主研发的含瓦斯煤多元气体竞争吸附试验系统进行不同含水率煤对CH4 和CO2 单组分吸附研究,试验结果表明:水分并没有改变CH4 和CO2 等温吸附曲线的基本规律,在相同条件下,水分也未影响煤对单组分气体吸附能力的排序,始终是煤对CO2 的吸附能力大于对CH4 的吸附能力.相同条件下,水分对CH4 的抑制率大于CO2 吸附量抑制率,说明水分对煤吸附弱吸附性气体的抑制程度更大.在进行水对混合气体的竞争吸附影响研究试验,发现:当注入煤体的气体比例保持不变时,在同一吸附平衡压力下,混合气体的吸附总量随着水分含量的升高而降低,并且吸附平衡后的CH4 吸附量和CO2 吸附量都随着煤体中水分含量的增大而减小;而当含水率不变时,同一注气比例下的气体吸附平衡压力越大,吸附平衡后的CH4 吸附量和CO2 吸附量越大.游离相中的CO2 的体积分数始终低于气源,而CH4 体积分数始终高于气源.不同条件下CO2/CH4 选择系数的数值均大于 1,范围处在 4.8~5.4,煤对CO2 的吸附亲和能力大于CH4.相同组分混合气体吸附条件下,CO2/CH4 选择系数均随着试验煤样含水率变大而降低.该研究进一步完善影响煤对气体吸附的因素的理论分析,以及为工程实践为井下注气促抽瓦斯技术提供理论依据.
Investigation on the impact of water on the competitive adsorption characteristics of CH4/CO2 in coal
In order to study the effect of water on the competitive adsorption of CH4/CO2 and mixed gases in coal,the self-developed multi-gas competitive adsorption experimental system of coal containing gas was used to conduct the research on the single component adsorp-tion of CH4 and CO2 by coal with different water content.The experimental results show that:Water does not change the basic law of the isothermal adsorption curve of CH4 and CO2,and under the same conditions,water does not affect the ordering of coal's adsorption capa-city for a single component of gas,and the adsorption capacity of coal for CO2 is always greater than that of CH4.Under the same condi-tions,the inhibition rate of water on CH4 is greater than that of CO2 adsorption capacity,indicating that the inhibition degree of water on coal's adsorption of weakly adsorbent gases is greater.The research on the effect of water on the competitive adsorption of mixed gas shows that:when the proportion of gas injected into the coal remains unchanged,under the same adsorption equilibrium pressure,the total adsorption of mixed gas decreases with the increase of water content,and the adsorption amount of CH4 and CO2 after adsorption equilibri-um decreases with the increase of water content in the coal.When the water content is unchanged,the greater the gas adsorption equilibri-um pressure under the same gas injection ratio,the greater the adsorption amount of CH4 and CO2 after adsorption equilibrium.The volume fraction of CO2 in the free phase is always lower than that of the gas source,while the volume fraction of CH4 is always higher than that of the gas source.Under different conditions,the values of CO2/CH4 selection coefficients are greater than 1,ranging from 4.8 to 5.4,and the adsorption affinity of coal for CO2 is greater than that of CH4.The selection coefficients of CO2/CH4 decrease with the in-crease of water content of coal samples under the same gas adsorption conditions.This study further improves the theoretical analysis of factors affecting coal gas adsorption,and provides a theoretical basis for engineering practice for underground gas injection and gas extrac-tion technology.

coalbed methanewater contentcompetitive adsorptionadsorption selectivitycoal absorbed gas

陈立伟、边乐、王东杰、郑浩阁、赵占川

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河南理工大学安全科学与工程学院,河南焦作 454000

煤炭安全生产与清洁高效利用省部共建协同创新中心,河南焦作 454000

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

煤层气 水分 竞争吸附 吸附选择性 煤吸附气体

国家自然科学基金河南省科技攻关计划

52074104222102320142

2024

煤炭科学技术
煤炭科学研究总院

煤炭科学技术

CSTPCD北大核心
影响因子:2.095
ISSN:0253-2336
年,卷(期):2024.52(4)
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