Test and analysis of coal adsorption volume of CH4
JIANG Yanhang , BAI Gang , ZHOU Xihua , WANG Yuxi , FU Tianyu, HU Kun
煤层中 CH4 主要以游离态和吸附态赋存,煤吸附 CH4 性能往往受煤阶、温度、压力、粒径 和含水率等多种因素共同影响,为研究多因素耦合对煤吸附 CH4 的 Langmuir 体积影响规律,选取山 西长治地区常村和赵庄煤矿煤样,利用 HCA–1 高压吸附装置测定不同环境温度、煤样粒径、含水率 的煤样吸附 CH4 体积,然后以赵庄矿煤样试验结果为基础,通过 Design Expert 软件设计 Box Behnken 试验,构建煤吸附 CH4 体积 2 次回归响应曲面模型,分析温度、粒径、含水率 3 种因素耦 合作用时对煤吸附 CH4 体积影响程度,并对不同条件下煤吸附 CH4 体积进行预测与验证,并探讨了 试验结果的工程应用启示。结果表明:CH4 吸附量随温度、粒径增加及含水率升高而降低;环境温 度由 15 ℃ 增加至 40 ℃ 时,常村及赵庄煤 CH4 吸附量分别降低 37.09%,37.5%;煤样粒径由 0.15 mm 增加至 0.3 mm 时,CH4 吸附量分别降低 14.87%、15.52%;常村煤样含水率由 0.08% 增至 4.21%, CH4 吸附量降低 10.61%,赵庄煤样含水率由 0.04% 增至 3.62%,CH4 吸附量降低 16.31%;温度、粒 径、含水率单因素作用均对 CH4 吸附量表现为极显著影响 (P<0.000 1),3 个因素对 CH4 吸附量的影 响程度为:温度 (F=2 307.95)>煤样粒径 (F=346.64)>含水率 (F=133.32);各交互项对 CH4 吸附量影 响程度为:粒径和含水率 (F=21.31)>温度和粒径 (F=6.33)>温度和含水率 (F=3.65),粒径与含水率交 互作用极显著 (P=0.002 4),温度和煤样粒径交互作用显著 (P=0.040 1),温度和含水率交互作用不显 著 (P=0.097 8);编码区间外试验值与模型预测值的偏差最大为 3.98%,最小为 2.01%,平均误差率 为 3.315%;井下回采过程中,温度、含水率、煤样粒径等多因素变化时,首先实时监测温度变化, 防止温度骤变引发瓦斯大量解吸,导致瓦斯超限甚至发生煤与瓦斯突出事故。
CH4 in coal seams mainly occurs in free state and adsorbed state. The performance of coal adsorption of CH4 is often affected by various factors such as coal rank, temperature, pressure, particle size and moisture content. In order to study the influence of multi-factor coupling on the Langmuir volume of coal adsorbing CH4 According to the law, coal samples from changcun and zhaozhuang Coal mines in Changzhi area of Shanxi are selected, and the HCA–1 high-pressure adsorption device is used to determine the volume of CH4 adsorbed by coal samples with different ambient temperature, coal sample size and water content, and then the test results of Zhaozhuang Coal mine Based on the design of the Box Behnken test using Design Expert software, a quadratic regression response surface model of coal adsorption CH4 volume was constructed to analyze the influence of temperature, particle size, and moisture content on the volume of coal adsorp- tion CH4 when the three factors are coupled. The volume of coal adsorbed CH4 was predicted and verified, and the engineering application enlightenment of the test results was discussed. The results show that the amount of CH4 adsorption decreases with the increase of temperature, particle size and moisture content; when the ambient temperature increases from 15 ℃ to 40 ℃, the amount of CH4 adsorption of Changcun and Zhaozhuang Coals decreases by 37.09% and 37.5%, respectively; coal samples When the particle size increases from 0.15 mm to 0.3 mm, the CH4 adsorption capacity decreases by 14.87% and 15.52%, respectively; the water content of the Changcun coal sample increases from 0.08% to 4.21%, the CH4 adsorption capacity decreases by 10.61%, and the water content of the Zhaozhuang coal sample decreases from Increased from 0.04% to 3.62%, the amount of CH4 adsorption decreased by 16.31%; the single factors of temperature, particle size, and water content all had a very significant impact on the amount of CH4 adsorption (P<0.000 1), and the degree of influence of the three factors on the amount of CH4 adsorption It is: temperature (F=2 307.95)> coal sample particle size (F=346.64)> water content (F=133.32); the degree of influence of each interaction item on the amount of CH4 adsorption is: particle size and water content (F=21.31)> temperature And particle size (F=6.33)>temperature and water content (F=3.65), the interaction between particle size and water content is extremely significant (P=0.002 4), and the interaction between temperature and coal sample particle size is significant (P=0.040 1). The interaction with water cut is not significant (P=0.097 8); the maximum deviation between the test value and the model prediction value outside the coding interval is 3.98%, the minimum is 2.01%, and the average error rate is 3.315%; during downhole recovery, temperature and water cut when the coal sample particle size and other factors change, firstly monitor the temperature change in real time to prevent the sudden change in temperature from causing a large amount of gas desorption, leading to excessive gas limit and even coal and gas outburst accidents.
coal; CH4 adsorption capacity; temperature; moisture content; particle size; response surface method
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会