脉冲超声波激励对煤的孔隙全尺度改造效应  

Stimulation effect of pulsed ultrasonic excitation on coal pores with full-scale pore sizes

作　　者：林海飞 仇悦[1] 韩双泽 高海东 杨二豪 王瑞哲 严敏 LIN Haifei;QIU Yue;HAN Shuangze;GAO Haidong;YANG Erhao;WANG Ruizhe;YAN Min(College of Safety Science and Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;Key Laboratory of Western Mine Exploitation and Hazard Prevention,Ministry of Education,Xi’an 710054,China;Shaanxi Huangling No.2 Coal Mine Co.,Ltd.,Huangling 727307,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]教育部西部矿井开采及灾害防治重点实验室,陕西西安710054 [3]陕西黄陵二号煤矿有限公司,陕西黄陵727307

出　　处：《煤田地质与勘探》2023年第8期139-149,共11页Coal Geology & Exploration

基　　金：国家自然科学基金面上项目(52174207);陕西省杰出青年科学基金项目(2020JC-48);陕西省自然科学基金项目(2019JLP-02)。

摘　　要：为深入研究脉冲超声波激励对煤体孔隙结构的改造效应,利用含瓦斯煤体超声波激励实验系统,开展超声波功率800和1 000 W持续、交互脉冲下煤的超声波激励实验,综合低压CO_(2)吸附、低温N_(2)吸附和高压压汞等实验,研究煤的大孔(>50 nm)、介孔(2~50 nm)、微孔(<2 nm)全孔径段的孔隙参数演化规律。实验结果表明:脉冲超声波对煤的孔隙具有扩孔效应,煤的孔容占比以微孔和大孔为主,介孔占比最小,煤中各孔径段比表面积大小为:微孔>介孔>大孔;与未超声、持续超声激励煤样相比,脉冲超声波激励煤的各孔径段孔容和比表面积均有所提高;随脉冲次数增加,煤的孔容增幅和比表面积增幅呈正线性增大,其中大孔的孔容和比表面积增幅较为显著。脉冲超声波激励煤样形成水锤压力阶段和滞止压力阶段的持续转换,增加了煤的孔隙结构损伤程度。研发脉冲超声波发射器结合水力化技术,可提高煤的孔隙发育程度,增加煤体渗透性,提高瓦斯抽采效率。This study aims to further investigate the stimulation effect of pulsed ultrasonic excitation on coal pore structures.Using an ultrasonic excitation test system for gas-containing coals,this study conducted ultrasonic excitation tests on coals under continuous and interactive pulses with ultrasonic power of 800 W and 1000 W.Through low-pressure CO_(2) adsorption tests,low-temperature nitrogen adsorption tests,and the mercury injection capillary pressure(MICP)tests,this study explored the evolutionary patterns of parameters of various coal pores with full-scale pore sizes,including macropores(>50 nm),mesopores(2‒50 nm),and micropores(<2 nm).The test results are as follows:(1)Pulsed ultrasonic waves can expand coal pores.The pore volume of coals was primarily provided by micropores and macropores,with mesopores representing a small proportion.The specific surface area of various coal pores was in the order of micropores>mesopores>macropores.(2)Compared with those having undergone continuous or no ultrasonic excitation,coal samples that experienced pulsed ultrasonic excitation exhibited increased pore volumes and specific surface areas of various core pores.(3)With an increase in the number of pulsed ultrasonic excitation,the increased amplitude of the pore volume and specific surface area of coal pores increased linearly.Most especially,macropores presented significantly high increased amplitude.Pulsed ultrasonic excitation caused the continuous transformation between the water hammer pressure stage and the stagnation pressure stage,which increased the level of damage to coal pore structures.Developing pulsed ultrasonic emitters,combined with hydraulic technology,can improve the developmental degree of coal pores,coal permeability,and gas drainage efficiency.

关 键 词：脉冲超声波 煤的孔隙结构 改造效应 联孔分布 

分 类 号：TD712[矿业工程—矿井通风与安全]