杨娟, 许思雨, 戴俊, 魏建平, 王云刚. 活化过硫酸铵溶液对煤样氧化增透的实验研究[J]. 煤炭学报, 2020, 45(4). DOI: 10.13225/j.cnki.jccs.2019.0955
引用本文: 杨娟, 许思雨, 戴俊, 魏建平, 王云刚. 活化过硫酸铵溶液对煤样氧化增透的实验研究[J]. 煤炭学报, 2020, 45(4). DOI: 10.13225/j.cnki.jccs.2019.0955
YANG Juan, XU Siyu, DAI Jun, WEI Jianping, WANG Yungang. Experimental study on oxidative improving-permeability of coal samples with activated ammonium persulfate solution[J]. Journal of China Coal Society, 2020, 45(4). DOI: 10.13225/j.cnki.jccs.2019.0955
Citation: YANG Juan, XU Siyu, DAI Jun, WEI Jianping, WANG Yungang. Experimental study on oxidative improving-permeability of coal samples with activated ammonium persulfate solution[J]. Journal of China Coal Society, 2020, 45(4). DOI: 10.13225/j.cnki.jccs.2019.0955

活化过硫酸铵溶液对煤样氧化增透的实验研究

Experimental study on oxidative improving-permeability of coal samples with activated ammonium persulfate solution

  • 摘要: 为提高过硫酸铵(APS)水溶液氧化增透煤样的效果,采用自制的非均相钴基活化剂(Co-NCP)活化过硫酸铵对长焰煤、焦煤、无烟煤3种不同变质程度的煤样进行氧化改性,系统研究了Co-NCP/APS体系改性对煤样表面接触角θ(润湿性)、孔隙结构、气体吸附常数、瓦斯放散初速度及渗透率的影响规律。实验结果表明:经过Co-NCP/APS体系处理可显著降低煤表面接触角θ与吸附甲烷能力,改性后长焰煤、焦煤、无烟煤的吸附常数a值降幅分别为16.15%,10.21%,6.03%,b值降幅分别为44.97%,41.10%,28.32%,瓦斯放散初速度降幅分别为49.19%,33.33%,12.55%。同时,经Co-NCP/APS体系处理能改变煤样的孔隙结构,改性后煤样的孔隙度增大,其中大、中孔的孔容占比增加,小、微孔孔容占比减少,对于长焰煤、焦煤、无烟煤的孔隙度增幅分别为43.50%,35.50%,12.54%,孔容增幅分别为56.02%,45.54%,20.08%。活化的过硫酸铵体系可原位生成大量具有强氧化能力的硫酸根自由基(SO·-4),能对不同变质程度的煤样表面实现氧化溶蚀,使煤孔隙中有机小分子相被部分氧化溶出,疏通了被小分子物质占据或封堵的孔道,使煤样孔隙连通性变好;同时,产生大量新的裂隙与孔洞,表明煤样经Co-NCP/APS体系处理能起到“增孔”、“扩孔”、“疏孔”的作用,且对变质程度越低的煤样氧化增透效果越明显,处理后长焰煤、焦煤、无烟煤的渗透率平均增幅分别为620.15%,541.02%,334.42%。可见,非均相钴基活化剂活化过硫酸铵溶液能氧化改性不同变质程度的煤样,显著降低煤样的亲甲烷能力,改善煤体内孔隙连通性与瓦斯在煤体中的流动性,使得煤体赋存瓦斯能力显著降低,为过硫酸铵水溶液对煤层增透方面的应用提供理论依据和实验支撑。

     

    Abstract: In order to improve the effect of ammonium persulfate (APS) aqueous solution on the oxidative im-proving- permeability of coal samples,the self-made heterogeneous cobalt-based activator (Co-NCP) was used to activate am- monium persulfate to oxidize and modify three kinds of coal samples with different metamorphic grades,including long- flame coal,coking coal and anthracite coal. The influences of Co-NCP / APS oxidative system on the contact angle θ (wettability),pore structure,gas adsorption constant,initial velocity of gas emission and permeability of coal samples were systematically investigated. The experimental results show that the treatment with Co-NCP / APS system can sig- nificantly decrease the contact angle θ of coal surface and the adsorption capacity of methane. After treated by Co- NCP / APS system,the adsorption constant a of long-flame coal,coking coal and anthracite coal decreases by 16. 15% , 10. 21% ,and 6. 03% ,the adsorption constant b decreases by 44. 97% ,41. 10% ,and 28. 32% and the initial velocity of gas emission decreases by 49. 19% ,33. 33% ,and 12. 55% ,respectively. Meanwhile,the pore structure of the coal samples can be changed by Co-NCP / APS treatment. After modification, the porosity of coal samples increases, in which the proportion of pore volume of large and medium pores increases,and that of small and micro pores decreases. The porosity of long-flame coal,coking coal and anthracite coal increases by 43. 50% ,35. 50% and 12. 54% accord- ingly,and the pore volume increases by 56. 02% ,45. 54% ,and 20. 08% respectively. For the activated ammonium persulfate system,a large amount of sulfate radicals (SO4·- ) with strong oxidative ability are in-situ generated,which can oxidize and corrode the surface of coal samples with different metamorphic grades. The organic small molecular phase are partially oxidized and dissolved out of the pores of coal samples. The pores occupied or blocked by small molecules are dredged,consequently improving the pore connectivity. In the meantime,a large number of new cracks and holes are created,demonstrating that the oxidative modification with Co-NCP / APS system plays the role of “ in- creasing pore”,“expanding pore”,and “dredging pore”. Moreover,for the coal samples with lower metamorphism de- gree,the improvement effect of permeability is more significant. After treated by Co-NCP / APS system,the average in- creases of permeability are 620. 15% ,541. 02% ,and 334. 42% for long-flame coal,coking coal and anthracite coal, respectively. As a result,the heterogeneous cobalt-based activator (Co-NCP) can activate ammonium persulfate solu- tion to oxidize and modify coal samples with different metamorphic degrees. This oxidative modification can reduce the coal’s affinity for methane,improve the pore connectivity of coal samples and the fluidity of gas in coal body,which thus significantly decreases the gas storage capacity of coal body. This study provides the theoretical basis and experi- mental support for the application of ammonium persulfate solution in improving permeability of coal seam.

     

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