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Pore structure characterization of coal particles via MIP, N2 and CO2 adsorption: Effect of coalification on nanopores evolution

Jiang, Jingyu, Yang, Weihua, Cheng, Yuanping, Zhao, Ke, Zheng, Shaojie
Powder technology 2019 v.354 pp. 136-148
adsorption, carbon dioxide, coal, fractal dimensions, mercury, micropores, nanopores, nitrogen, porosimetry, porosity, powders, China
To study the pore structure characteristics of middle-high rank coals (MHRC), five different kinds of coal samples from northern China were selected and pulverized, and the pore volume, pore size distribution, and fractal dimension were analyzed using N2/CO2 adsorption and mercury intrusion porosimetry. The results show that the nanopores size of MHRC tends to decrease with the increase of coal rank, especially the ultra-micropores dominate in semi-anthracite coal. In addition, the fractal dimensions of the adsorption pore (pores >0.5 nm and pores <0.5 nm) are calculated, respectively. Both of these fractal dimension-fitting curves exhibit a U-shaped parabolic relationship with the Ro. It can be found that the nanopores is affected by the coalification jumps by analyzing the relationship between the pore structure parameters and Ro. The third coalification jump has a turning effect on the micropores development, and the fifth coalification jump significantly promoted the mesopores volume.