基于双位Langmuir模型活性炭的CH4吸附特征  

Adsorption characteristics of CH4 on activated carbon based on the dual-site Langmuir model

作　　者：岳高伟[1] 王路 李敏敏[1] 蔺海晓[1] YUE Gaowei;WANG Lu;LI Minmin;LIN Haixiao(School of Civil Engineering,Henan Polytechnic University,Jiaozuo,Henan 454000,China)

机构地区：[1]河南理工大学土木工程学院

出　　处：《天然气工业》2020年第4期125-132,共8页Natural Gas Industry

基　　金：国家自然科学基金项目“冲击载荷下高阶煤的大分子结构及微观/纳观孔隙的动态响应特征及其机制”(编号:41772163)。

摘　　要：较之于压缩天然气存储和液化天然气存储,天然气吸附存储(ANG)方式具有能显著降低储存压力和运行成本的优点,然而,要将测定的吸附量转化为绝对吸附量,需要采用合适的模型。为了准确预测活性炭上甲烷的总储存量,采用双位Langmuir模型描述并准确预测了甲烷在活性炭上的吸附行为,误差在5%以内;进而解释了温度介于283.15~323.15 K、压力介于0.1~14.0 MPa条件下,活性炭上甲烷吸附平衡的临界点。研究结果表明:①在过剩吸附量超过极大值后,不同温度下的吸附等温线将出现交叉现象,在交叉点后,温度越高过剩吸附量越大;②甲烷的吸附相体积和气相密度,随平衡温度和压力的变化而变化,随着温度的升高,体积密度项对于绝对吸附量的贡献逐渐减小;③在343.15 K和14 MPa以下,实际吸附甲烷量超过86.9%,游离甲烷相含量低于13.1%,游离甲烷相含量的贡献率随温度的升高而逐渐增大。结论认为,该模型能快速、准确地预测真实的甲烷存储量,可以为大型天然气吸附存储技术的研究和开发提供帮助。Compared with compressed natural gas(CNG)storage and liquefied natural gas(LNG)storage,adsorbed natural gas(ANG)is more advantageous with lower storage pressure and operation cost.To convert the measured adsorption quantity to the absolute adsorption quantity,however,it is necessary to adopt an appropriate model.In order to accurately predict the total methane storage on activated carbon,this paper described and accurately predicted methane's adsorption behavior on activated carbon using the dual-site Langmuir model with the error no more than 5%.Then,the critical point corresponding to the methane adsorption equilibrium on activated carbon under the temperature of 283.15-323.15 K and the pressure of 0.1-14.0 MPa was interpreted.And the following research results were obtained.First,after the excess adsorption quantity is higher than the maximum value,crossover phenomenon will occur in the adsorption isotherm contours of different temperatures.And after the cross point,the excess adsorption quantity increases with the increase of temperature.Second,the adsorbed phase volume and the gas phase density of methane change with equilibrium temperature and pressure.And the contribution of the volume–density term to the absolute adsorption quantity gradually becomes less as the temperature increases.Third,under less than 343.15 K and 14 MPa,the actual adsorbed methane accounts for more than 86.9%,the content of free methane phase is less than 13.1%,and the contribution rate of the content of free methane phase increases gradually with the increase of temperature.In conclusion,this model can predict the real methane storage quickly and accurately,and can provide assistance for the research and development of large-scale natural gas storage technologies.

关 键 词：天然气吸附存储(ANG) 过剩吸附 绝对吸附 吸附量 温度 活性炭 双位Langmuir模型 精准预测 

分 类 号：P618.13[天文地球—矿床学]