This study examined the influence of particle sizes and adsorption equilibrium time (AET) on pore structure characterization using low pressure N₂ adsorption (LPGA-N₂) method. The results demonstrate that pore structures change with progressive crushing. The increase in pore volume in the minipore and mesopore with decreasing coal particle sizes was caused by creating additional large pores during the crushing. The tendency of decreasing at first and then increasing was observed for both the specific surface area (SSA) and micropore volume, demonstrating that the micropore structure was primarily damaged and then followed by additional micropores being created when the sample was broken down smaller than 80 mesh. It is difficult to choose a suitable coal particle size for LPGA-N₂ measurement to yield pore structure parameters closest to the “real” values due to the difficulty in evaluating the compound effect of crushing on pore structures. To make testing results closer to the coal structure under in situ conditions, we propose 1∼3 mm as the preferred coal particle size. Additionally, many replicate experiments were performed by adjusting the AET to ensure LPGA-N₂ isotherms in equilibrium states. The results indicate that a decrease in particle size did not reduce the time for reaching N₂ adsorption equilibrium. Comparison of pore size distributions under different AETs shows that the AETs' increase has a little influence on the measurement of minipore and mesopore but has a positive correlation with micropore, revealing that N₂ adsorption equilibrium is mainly influenced by the micropore whose volume is underestimated at small AETs. The optimal AET for LPGA-N₂ measurement was 8 min and its yielded data can more accurately characterize the pore structure parameters.

本研究使用低压N ₂吸附（LPGA-N ₂）方法研究了粒径和吸附平衡时间（AET）对孔结构表征的影响。结果表明，孔结构随着逐渐破碎而改变。小孔和中孔的孔体积随着煤颗粒尺寸的减小而增加，是由于在破碎过程中产生了额外的大孔而引起的。对于比表面积（SSA）和微孔体积，先观察到先减小然后增加的趋势，这表明微孔结构首先受到破坏，然后当样品破碎到小于80目时，会产生附加的微孔。 。很难为LPGA-N选择合适的煤粒度由于难以评估破碎对孔隙结构的复合作用，因此进行_2次测量以产生最接近“真实”值的孔隙结构参数。为了使测试结果更接近原位条件下的煤结构，我们建议使用1〜3 mm作为首选煤粒度。另外，通过调节AET以确保LPGA-N ₂等温线处于平衡状态，进行了许多重复实验。结果表明，减小粒径并没有减少达到N ₂吸附平衡的时间。比较不同AET的孔径分布表明，AET的增加对微孔和中孔的测量影响很小，但与微孔呈正相关，表明N ₂吸附平衡主要受微孔的影响，微孔的体积在小AET时被低估了。用于LPGA-N ₂测量的最佳AET为8分钟，其产生的数据可以更准确地表征孔结构参数。