Experimental Investigation of the Thermal Expansion Characteristics of Anthracite Coal Induced by Gas Adsorption

Ran Wang, X. Su, Shiyao Yu, Linan Su, Jie Hou, Qian Wang
{"title":"Experimental Investigation of the Thermal Expansion Characteristics of Anthracite Coal Induced by Gas Adsorption","authors":"Ran Wang, X. Su, Shiyao Yu, Linan Su, Jie Hou, Qian Wang","doi":"10.1155/2023/5201794","DOIUrl":null,"url":null,"abstract":"The coal matrix can expand after gas adsorption, thus reducing the permeability of coal reservoirs and further affecting the coalbed methane production. Whether the heat released by coal adsorbing gas is a cause of the coal expansion has not yet been determined. Therefore, the anthracite coal with high gas adsorption capacity was used; under the conditions of 35°C and 1-6 MPa, the adsorption capacity and the adsorption heat of coal adsorbing CO2 and CH4 were tested. The specific heat capacity and thermal expansion coefficient of coal at 35°C were tested. The temperature change of the coal after being heated was calculated by combining the absorption heat and specific heat capacity; also, the thermal expansion rate was calculated by combining the temperature change and expansion coefficient. In addition, the cube law was used to calculate the permeability change of coal before and after the adsorption expansion. The results show that the changes in the gas adsorption capacity and adsorption heat of the coal obey the Langmuir equation, and those to CO2 are both higher than to CH4. The temperature of coal increases after the heat is released in the process of CO2 and CH4 adsorption, and the temperature change of coal adsorbing CO2 and CH4 reaches 102°C and 72°C, respectively, at 6 MPa. The thermal expansion rate of coal adsorbing CO2 and CH4 reaches 5.40% and 3.81%, at 6 MPa, respectively. It is found that a higher gas pressure could lead to a higher temperature change, a higher thermal expansion rate, as well as a higher thermal expansion and coal deformation. After the adsorption of CO2 and CH4, the coal permeability is reduced by 20.43% and 14.66%, respectively, at 6 MPa. Both the thermal expansion rate and the permeability change with the gas adsorption pressure obey the Langmuir equation. Therefore, the adsorption expansion of coal may be thermal expansion caused by the heat released by coal adsorbing gas.","PeriodicalId":7279,"journal":{"name":"Adsorption Science & Technology","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2023-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Adsorption Science & Technology","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1155/2023/5201794","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 1

Abstract

The coal matrix can expand after gas adsorption, thus reducing the permeability of coal reservoirs and further affecting the coalbed methane production. Whether the heat released by coal adsorbing gas is a cause of the coal expansion has not yet been determined. Therefore, the anthracite coal with high gas adsorption capacity was used; under the conditions of 35°C and 1-6 MPa, the adsorption capacity and the adsorption heat of coal adsorbing CO2 and CH4 were tested. The specific heat capacity and thermal expansion coefficient of coal at 35°C were tested. The temperature change of the coal after being heated was calculated by combining the absorption heat and specific heat capacity; also, the thermal expansion rate was calculated by combining the temperature change and expansion coefficient. In addition, the cube law was used to calculate the permeability change of coal before and after the adsorption expansion. The results show that the changes in the gas adsorption capacity and adsorption heat of the coal obey the Langmuir equation, and those to CO2 are both higher than to CH4. The temperature of coal increases after the heat is released in the process of CO2 and CH4 adsorption, and the temperature change of coal adsorbing CO2 and CH4 reaches 102°C and 72°C, respectively, at 6 MPa. The thermal expansion rate of coal adsorbing CO2 and CH4 reaches 5.40% and 3.81%, at 6 MPa, respectively. It is found that a higher gas pressure could lead to a higher temperature change, a higher thermal expansion rate, as well as a higher thermal expansion and coal deformation. After the adsorption of CO2 and CH4, the coal permeability is reduced by 20.43% and 14.66%, respectively, at 6 MPa. Both the thermal expansion rate and the permeability change with the gas adsorption pressure obey the Langmuir equation. Therefore, the adsorption expansion of coal may be thermal expansion caused by the heat released by coal adsorbing gas.
气体吸附诱导无烟煤热膨胀特性的实验研究
气体吸附后,煤基质会膨胀,从而降低煤储层的渗透率,进一步影响煤层气产量。煤吸附气体释放的热量是否是煤膨胀的原因还没有确定。因此,选用气体吸附能力高的无烟煤;在35℃、1 ~ 6 MPa条件下,测试了煤对CO2和CH4的吸附量和吸附热。测试了煤在35℃时的比热容和热膨胀系数。结合吸收热和比热容计算煤受热后的温度变化;并结合温度变化和膨胀系数计算了热膨胀率。此外,利用立方定律计算了吸附膨胀前后煤的渗透率变化。结果表明:煤的气体吸附量和吸附热的变化符合Langmuir方程,对CO2的吸附量和吸附热的变化均大于对CH4的吸附量。煤在吸附CO2和CH4过程中释放热量后温度升高,在6 MPa下吸附CO2和CH4时煤的温度变化分别达到102℃和72℃。在6 MPa条件下,煤吸附CO2和CH4的热膨胀率分别达到5.40%和3.81%。研究发现,瓦斯压力越高,煤的温度变化越大,热膨胀率越高,煤的热膨胀和变形也越大。吸附CO2和CH4后,在6 MPa下煤的渗透率分别降低20.43%和14.66%。热膨胀率和渗透率随气体吸附压力的变化均符合Langmuir方程。因此,煤的吸附膨胀可能是煤吸附气体放出的热量引起的热膨胀。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
自引率
0.00%
发文量
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信