Stimulation effect of pulsed ultrasonic excitation on coal pores with full-scale pore sizes
LIN Haifei;QIU Yue;HAN Shuangze;GAO Haidong;YANG Erhao;WANG Ruizhe;YAN Min
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CO2吸附、低温N2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(
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 CO2 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.
pulsed ultrasonic wave;coal pore structure;stimulation effect;combination of pores with full-scale pore sizes
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