The dynamic change of pore structure for low-rank coal under refined upgrading pretreatment temperatures

• 作者: Teng Li Cai-Fang Wu Zi-Wei Wang
• 来源期刊: 石油科学（英文版）
• 年，卷（期）: 2021,（2）
• 所属期刊栏目: PETROLEUM GEOLOGY & GEOPHYSICS
• 页码范围: 430-443
• 页数: 14页
• 语种: 英文

摘要

Pore structure characteristics are significant factor in the evaluation of the physical characteristics of low-rank coal.In this study,three low-rank coal samples were collected from the Xishanyao Formation,Santanghu Basin,and low-temperature liquid-nitrogen adsorption(LP-N2A)measurements were taken under various pretreatment temperatures.Owing to the continuous loss of water and volatile matter in low-rank coal,the total pore volume assumes a three-step profile with knee temperatures of 150℃and 240℃.However,the ash in the coal can protect the coal skeleton.Pore collapse mainly occurs for mesopores with aperture smaller than 20 nm.Mesopores with apertures smaller than 5 nm exhibit a continuous decrease in pore volume,whereas the pore volume of mesopores with apertures ranging from 5 to 10 nm increases at lower pretreatment temperatures(＜150℃)followed by a faint decrease.As for mesopores with apertures larger than 10 nm,the pore volume increases significantly when the pretreatment temperature reaches 300℃.The pore structure of low-rank coal features a significant heating effect,the pretreatment temperature should not exceed 150℃when the LP-N2A is used to evaluate the pore structure of low-rank coal to effectively evaluate the reservoir characteristics of low-rank coal.