煤对CO_2的解吸实验及热力学参数研究  

Desorption experiments and thermodynamic parameters of coal for CO_2

作　　者：邓军 任立峰[1,2] 吴明明 马砺[1,2] 翟小伟 DENG Jun;REN Li-Feng;WU Ming-ming;MA Li;ZHAI Xiao-wei(College of Safety Science and Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;Shaanxi Key Laboratory of Prevention and Control of Coal Fire,Xi’an University of Science and Technology,Xi’an 710054,China;Erdos City Yingpanhao Coal Co.,Ltd.,Ordos 017300,China)

机构地区：[1]西安科技大学安全科学与工程学院,陕西西安710054 [2]西安科技大学陕西省煤火灾害防治重点实验室,陕西西安710054 [3]鄂尔多斯市营盘壕煤炭有限公司,内蒙古鄂尔多斯017300

出　　处：《西安科技大学学报》2018年第5期697-704,共8页Journal of Xi’an University of Science and Technology

基　　金：国家自然科学基金(51204136;51574139;51674191)

摘　　要：为研究煤对CO_2的解吸过程及其热力学特性,采用吸附常数测定仪在303~343 K,解吸平衡压力从5 MPa到0. 1 MPa情况下进行煤对CO_2的解吸实验,得到了4种煤样对CO_2的解吸等温曲线。研究4种煤样在不同温度时对CO_2解吸等温线变化规律以及对应的吸附模型,并计算得到煤对CO_2解吸过程中的等量吸附热。结果表明:随解吸体系温度升高,CO_2对煤表面不均匀程度的敏感性逐渐降低。因此,温度在303~323 K之间时,4种煤样对CO_2的解吸过程符合Freundlich模型;在333~343 K时,煤样对CO_2的解吸等温线符合Langmuir模型。煤对CO_2解吸的特征温度分别为:270 K(LHG)、277 K(WW)、278 K(LG)和298 K(WJL),解吸特征温度随煤变质程度的升高而升高。煤对CO_2的解吸过程中等量吸附热在吸附量为0. 1 mmol/g时在-60^-90 kJ/mol之间变化; CO_2气体在煤表面解吸过程中的等量吸附热随吸附量的增加呈Qst=cln(N)+d的对数降低规律,煤对CO_2的解吸能力随吸附量的增加而逐渐增强。研究结果对CO_2在煤表面的吸附解吸机理的研究以及利用CO_2在增产煤层气方面的应用提供一定的参考。In order to study the desorption process and thermodynamic characteristics of coal for CO 2,CO 2 desorption experiment was conducted in 303~343 K and equilibrium pressure of desorption from 5~0.1 MPa by adsorption constants detector.Therefore,the desorption isotherms of four kinds of coal samples were obtained.The variation law of desorption isotherms of CO 2 and adsorption models of four coal samples at different temperatures were studied,and the isothermal adsorption heats of CO 2 during desorption were calculated.The results indicated that the increases of desorption temperature gradually decreases of sensitivity of CO 2 to the unevenness of coal surface.The desorption process of the four coal samples for CO 2 was in accordance with Freundlich model when the temperature was between 303~323 K.However,when desorption temperature was 333 K and 343 K,the desorption isotherms of coal samples for CO 2 complied with the Langmuir model.The characteristic temperatures of desorption of four kinds of coal samples for CO 2 were 270 K(LHG),277 K(WW),278 K(LG)and 298 K(WJL),respectively,which rose with the increase of coal rank.The isosteric heat of adsorption varied from-60~90 kJ/mol when the adsorption capacity was 0.1 mmol/g.The isosteric heat of adsorption of CO 2 desorbed on coal surface decreased logarithmically as Q st=c ln(N)+d with the increase of adsorption amount.The desorption capacity of CO 2 enhances gradually with the increase of adsorption capacity.The research results can provide cerain references for study on adsorption and desorption mechanism of CO 2 on coal surface and application of CO 2 in increasing production of coalbed methane.

关 键 词：煤 解吸 CO2 热力学 吸附热 

分 类 号：X936[环境科学与工程—安全科学]