煤田地质与勘探2024，Vol.52Issue(7)：46-53,8.DOI:10.12363/issn.1001-1986.23.12.0825
富油煤热解特性及其孔裂隙结构演化规律
Pyrolysis characteristics and pore-fracture evolutionary patterns of tar-rich coals
摘要
Abstract
[Objective]Extracting coal-based oil and gas from tar-rich coal through in situ pyrolysis plays a significant role in counteracting the shortage of China's oil and gas resources and enhancing the utilization efficiency of coal re-sources,representing a new trend for the efficient exploitation of tar-rich coals.During the in situ pyrolysis of tar-rich coals,the internal heat transfer,as well as the migration and production of pyrolysis products,is directly influenced by the oil and gas production characteristics and the characteristics of pores and fractures.Hence,it is particularly critical to identify the pyrolysis characteristics and pore-fracture evolutionary patterns of tar-rich coals.[Methods]Using a self-de-veloped pyrolysis test device,alongside a specific surface area and pore size analyzer,a three-dimensional microscope,and a simultaneous thermal analyzer,this study recorded the gas production regularities of tar-rich coals under different pyrolysis temperatures,determined the microscopic pore structures and pore size distributions of tar-rich coals after pyrolysis,and analyzed the fracture evolutionary patterns and surface fracture parameters,ultimately revealing the mech-anisms behind the responses of coal structures and pyrolysis products to the pyrolysis temperature.[Results and Con-clusions]The results show that the total gas production and the maximum gas production rate of tar-rich coals through pyrolysis increased with temperature.When the temperature exceeded 300℃,the pyrolysis reactions became violent,accompanied by significantly increased gas production.The comparison of the pore and fracture structures under differ-ent pyrolysis temperatures revealed that the pore structure types changed with 300℃as a threshold.Below 300℃,the pore types after pyrolysis were dominated by small bottlenecks and fractures/wedge-shaped pores,which were primarily mesopores.With an increase in the temperature,the predominant pore types transitioned to parallel slits,micropores in-creased,and mesopores and macropores further propagated and interconnected,forming microfractures.Compared to coal samples subjected to low temperatures,coal samples at high temperatures manifested elevated fracture aperture,fracture network density,and surface fracture ratio,as well as macroscopically damaged structures and reduced integrity.The evolution of pore-fracture structures during the pyrolysis of tar-rich coals was attributed to the combined effects of water evaporation,the desorption and precipitation of adsorbed gas,uneven thermal expansion,the pyrolysis of organic matter,and the escape of pyrolysis gas.The findings of this study serve as a useful reference for selecting parameters for in situ pyrolysis of tar-rich coals.关键词
富油煤/热解/产气规律/孔裂隙演化/热力学分析Key words
tar-rich coal/pyrolysis/gas production regularity/pore-fracture evolution/thermodynamic analysis分类
化学化工引用本文复制引用
耿济世,王双明,孙强,侯恩科,杨玉茹,胡鑫,薛圣泽..富油煤热解特性及其孔裂隙结构演化规律[J].煤田地质与勘探,2024,52(7):46-53,8.基金项目
陕西省"两链"融合重点专项项目(2023-LL-QY-05) （2023-LL-QY-05）
国家自然科学基金项目(42330808,42272209) （42330808,42272209）
陕西省自然科学基础研究计划项目(2024JC-YBQN-0289) （2024JC-YBQN-0289）
陕西省博士后科研项目(2023BSHEDZZ304) （2023BSHEDZZ304）
