In this paper, aiming at the difficulty of gas extraction in low permeability coal seam in China, the influence of nitric acid acidification technology on gas desorption characteristics of coal body is studied. Taking lignite in Qinshui Basin as a sample, through different concentrations of nitric acid acidification treatment, combined with gas isothermal desorption experiment and initial velocity test, the influence mechanism of acidification on gas desorption amount, desorption rate and initial velocity was systematically analyzed. The results show that nitric acid acidification can dissolve the mineral impurities in the pores and fissures of coal and improve the pore connectivity. Under the same adsorption pressure, the cumulative gas desorption amount of coal samples after acidification increases with the increase of nitric acid concentration. The initial desorption rate of acidified coal samples increased significantly, and the desorption rate increased with the increase of nitric acid concentration. Acidification reduces the initial velocity of gas emission Δp, indicating that acidification may inhibit the initial rapid release of gas by increasing the complexity of pore structure. This study provides a theoretical basis for the application of nitric acid acidification technology in coal seam permeability enhancement and gas efficient extraction.
李朋峰1,李 斌2,蒋李进3. 硝酸酸化对煤体瓦斯解吸特征的影响[J]. 煤炭与化工, 2025, 48(11): 100-104,110..
Li Pengfeng 1, Li Bin 2, Jiang Lijin 3. Effect of nitric acid acidification on gas desorption characteristics of coal. CCI, 2025, 48(11): 100-104,110..
[ 15 ] RN Lieberman, X Querol, N Moreno, Y Mastai, H Cohen. Physical and chemical changes in coal fly ash during acidic or neutral wastes treatment, and its’ effect on the fixation process. Fuel, 2016, 184: 69 - 80.
[ 16 ] 李海涛,邓少贵,牛云峰,等. 低孔渗砂岩孔隙结构分类方法研究[ J ]. CT理论与应用研究,2018,27( 5 ):551 - 560.
[ 17 ] 蔺亚兵,贾雪梅,马东民. 基于液氮吸附法对煤的孔隙特征研究与应用[ J ]. 煤炭科学技术,2016,44( 3 ):135 - 140.
[ 18 ] Wang ZY, Cheng YP, Qi YX, Wang RP, Wang L, Jiang JY. Expe-
rimental study of pore structure and fractal characteristics of pulverized intact coal and tectonic coal by low temperature nitrogen adsorption. Powder Technology, 2019, 350: 15 - 25.
[ 19 ] Wang ZY, Cheng YP, Qi YX, Wang RP, Wang L, Jiang JY. Expe-
rimental study of pore structure and fractal characteristics of pulverized intact coal and tectonic coal by low temperature nitrogen adsorption. Powder Technology, 2019, 350: 15 - 25.
[ 20 ] Li PP, Zhang XD, Zhang S. Structures and fractal characteristics of pores in low volatile bituminous deformed coals by low-temperature N2 adsorption after di?erent solvents treatments. Fuel, 2018, 24: 661 - 675.